@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-@c 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+@c 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+@c Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
@ignore
+@c man begin INCLUDE
+@include gcc-vers.texi
+@c man end
+
@c man begin COPYRIGHT
-Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
-1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
+under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``GNU General Public License'' and ``Funding
Free Software'', the Front-Cover texts being (a) (see below), and with
[@option{-I}@var{dir}@dots{}] [@option{-L}@var{dir}@dots{}]
[@option{-D}@var{macro}[=@var{defn}]@dots{}] [@option{-U}@var{macro}]
[@option{-f}@var{option}@dots{}] [@option{-m}@var{machine-option}@dots{}]
- [@option{-o} @var{outfile}] @var{infile}@dots{}
+ [@option{-o} @var{outfile}] [@@@var{file}] @var{infile}@dots{}
Only the most useful options are listed here; see below for the
remainder. @samp{g++} accepts mostly the same options as @samp{gcc}.
@c man end
@c man begin SEEALSO
gpl(7), gfdl(7), fsf-funding(7),
-cpp(1), gcov(1), g77(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1)
-and the Info entries for @file{gcc}, @file{cpp}, @file{g77}, @file{as},
+cpp(1), gcov(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1)
+and the Info entries for @file{gcc}, @file{cpp}, @file{as},
@file{ld}, @file{binutils} and @file{gdb}.
@c man end
@c man begin BUGS
For instructions on reporting bugs, see
-@w{@uref{http://gcc.gnu.org/bugs.html}}. Use of the @command{gccbug}
-script to report bugs is recommended.
+@w{@value{BUGURL}}.
@c man end
@c man begin AUTHOR
See the Info entry for @command{gcc}, or
@cindex options, GCC command
@c man begin DESCRIPTION
-
When you invoke GCC, it normally does preprocessing, compilation,
assembly and linking. The ``overall options'' allow you to stop this
process at an intermediate stage. For example, the @option{-c} option
@cindex options, grouping
The @command{gcc} program accepts options and file names as operands. Many
options have multi-letter names; therefore multiple single-letter options
-may @emph{not} be grouped: @option{-dr} is very different from @w{@samp{-d
--r}}.
+may @emph{not} be grouped: @option{-dv} is very different from @w{@samp{-d
+-v}}.
@cindex order of options
@cindex options, order
You can mix options and other arguments. For the most part, the order
-you use doesn't matter. Order does matter when you use several options
-of the same kind; for example, if you specify @option{-L} more than once,
-the directories are searched in the order specified.
+you use doesn't matter. Order does matter when you use several
+options of the same kind; for example, if you specify @option{-L} more
+than once, the directories are searched in the order specified. Also,
+the placement of the @option{-l} option is significant.
Many options have long names starting with @samp{-f} or with
-@samp{-W}---for example, @option{-fforce-mem},
-@option{-fstrength-reduce}, @option{-Wformat} and so on. Most of
+@samp{-W}---for example,
+@option{-fmove-loop-invariants}, @option{-Wformat} and so on. Most of
these have both positive and negative forms; the negative form of
@option{-ffoo} would be @option{-fno-foo}. This manual documents
only one of these two forms, whichever one is not the default.
@xref{Option Index}, for an index to GCC's options.
@menu
-* Option Summary:: Brief list of all options, without explanations.
+* Option Summary:: Brief list of all options, without explanations.
* Overall Options:: Controlling the kind of output:
an executable, object files, assembler files,
or preprocessed source.
-* Invoking G++:: Compiling C++ programs.
+* Invoking G++:: Compiling C++ programs.
* C Dialect Options:: Controlling the variant of C language compiled.
* C++ Dialect Options:: Variations on C++.
-* Objective-C Dialect Options:: Variations on Objective-C.
+* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C
+ and Objective-C++.
* Language Independent Options:: Controlling how diagnostics should be
formatted.
* Warning Options:: How picky should the compiler be?
* Code Gen Options:: Specifying conventions for function calls, data layout
and register usage.
* Environment Variables:: Env vars that affect GCC.
+* Precompiled Headers:: Compiling a header once, and using it many times.
* Running Protoize:: Automatically adding or removing function prototypes.
@end menu
@table @emph
@item Overall Options
@xref{Overall Options,,Options Controlling the Kind of Output}.
-@gccoptlist{
--c -S -E -o @var{file} -pipe -pass-exit-codes -x @var{language} @gol
--v -### --help --target-help --version}
+@gccoptlist{-c -S -E -o @var{file} -combine -pipe -pass-exit-codes @gol
+-x @var{language} -v -### --help@r{[}=@var{class}@r{[},@dots{}@r{]]} --target-help @gol
+--version -wrapper@@@var{file}}
@item C Language Options
@xref{C Dialect Options,,Options Controlling C Dialect}.
-@gccoptlist{
--ansi -std=@var{standard} -aux-info @var{filename} @gol
--fno-asm -fno-builtin -fno-builtin-@var{function} @gol
--fhosted -ffreestanding @gol
+@gccoptlist{-ansi -std=@var{standard} -fgnu89-inline @gol
+-aux-info @var{filename} @gol
+-fno-asm -fno-builtin -fno-builtin-@var{function} @gol
+-fhosted -ffreestanding -fopenmp -fms-extensions @gol
-trigraphs -no-integrated-cpp -traditional -traditional-cpp @gol
--fallow-single-precision -fcond-mismatch @gol
+-fallow-single-precision -fcond-mismatch -flax-vector-conversions @gol
-fsigned-bitfields -fsigned-char @gol
--funsigned-bitfields -funsigned-char @gol
--fwritable-strings}
+-funsigned-bitfields -funsigned-char}
@item C++ Language Options
@xref{C++ Dialect Options,,Options Controlling C++ Dialect}.
-@gccoptlist{
--fno-access-control -fcheck-new -fconserve-space @gol
--fno-const-strings -fdollars-in-identifiers @gol
+@gccoptlist{-fabi-version=@var{n} -fno-access-control -fcheck-new @gol
+-fconserve-space -ffriend-injection @gol
-fno-elide-constructors @gol
--fno-enforce-eh-specs -fexternal-templates @gol
--falt-external-templates @gol
+-fno-enforce-eh-specs @gol
-ffor-scope -fno-for-scope -fno-gnu-keywords @gol
-fno-implicit-templates @gol
-fno-implicit-inline-templates @gol
-fno-nonansi-builtins -fno-operator-names @gol
-fno-optional-diags -fpermissive @gol
-frepo -fno-rtti -fstats -ftemplate-depth-@var{n} @gol
--fuse-cxa-atexit -fvtable-gc -fno-weak -nostdinc++ @gol
--fno-default-inline -Wabi -Wctor-dtor-privacy @gol
+-fno-threadsafe-statics -fuse-cxa-atexit -fno-weak -nostdinc++ @gol
+-fno-default-inline -fvisibility-inlines-hidden @gol
+-fvisibility-ms-compat @gol
+-Wabi -Wctor-dtor-privacy @gol
-Wnon-virtual-dtor -Wreorder @gol
--Weffc++ -Wno-deprecated @gol
+-Weffc++ -Wstrict-null-sentinel @gol
-Wno-non-template-friend -Wold-style-cast @gol
-Woverloaded-virtual -Wno-pmf-conversions @gol
--Wsign-promo -Wsynth}
-
-@item Objective-C Language Options
-@xref{Objective-C Dialect Options,,Options Controlling Objective-C Dialect}.
-@gccoptlist{
--fconstant-string-class=@var{class-name} @gol
--fgnu-runtime -fnext-runtime -gen-decls @gol
--Wno-protocol -Wselector}
+-Wsign-promo}
+
+@item Objective-C and Objective-C++ Language Options
+@xref{Objective-C and Objective-C++ Dialect Options,,Options Controlling
+Objective-C and Objective-C++ Dialects}.
+@gccoptlist{-fconstant-string-class=@var{class-name} @gol
+-fgnu-runtime -fnext-runtime @gol
+-fno-nil-receivers @gol
+-fobjc-call-cxx-cdtors @gol
+-fobjc-direct-dispatch @gol
+-fobjc-exceptions @gol
+-fobjc-gc @gol
+-freplace-objc-classes @gol
+-fzero-link @gol
+-gen-decls @gol
+-Wassign-intercept @gol
+-Wno-protocol -Wselector @gol
+-Wstrict-selector-match @gol
+-Wundeclared-selector}
@item Language Independent Options
@xref{Language Independent Options,,Options to Control Diagnostic Messages Formatting}.
-@gccoptlist{
--fmessage-length=@var{n} @gol
--fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]}}
+@gccoptlist{-fmessage-length=@var{n} @gol
+-fdiagnostics-show-location=@r{[}once@r{|}every-line@r{]} @gol
+-fdiagnostics-show-option}
@item Warning Options
@xref{Warning Options,,Options to Request or Suppress Warnings}.
-@gccoptlist{
--fsyntax-only -pedantic -pedantic-errors @gol
--w -W -Wall -Waggregate-return @gol
--Wcast-align -Wcast-qual -Wchar-subscripts -Wcomment @gol
--Wconversion -Wno-deprecated-declarations @gol
--Wdisabled-optimization -Wdiv-by-zero -Werror @gol
--Wfloat-equal -Wformat -Wformat=2 @gol
--Wformat-nonliteral -Wformat-security @gol
--Wimplicit -Wimplicit-int @gol
--Wimplicit-function-declaration @gol
--Werror-implicit-function-declaration @gol
--Wimport -Winline @gol
--Wlarger-than-@var{len} -Wlong-long @gol
--Wmain -Wmissing-braces @gol
--Wmissing-format-attribute -Wmissing-noreturn @gol
--Wmultichar -Wno-format-extra-args -Wno-format-y2k @gol
--Wno-import -Wpacked -Wpadded @gol
--Wparentheses -Wpointer-arith -Wredundant-decls @gol
+@gccoptlist{-fsyntax-only -pedantic -pedantic-errors @gol
+-w -Wextra -Wall -Waddress -Waggregate-return -Warray-bounds @gol
+-Wno-attributes -Wno-builtin-macro-redefined @gol
+-Wc++-compat -Wc++0x-compat -Wcast-align -Wcast-qual @gol
+-Wchar-subscripts -Wclobbered -Wcomment @gol
+-Wconversion -Wcoverage-mismatch -Wno-deprecated @gol
+-Wno-deprecated-declarations -Wdisabled-optimization @gol
+-Wno-div-by-zero -Wempty-body -Wenum-compare -Wno-endif-labels @gol
+-Werror -Werror=* @gol
+-Wfatal-errors -Wfloat-equal -Wformat -Wformat=2 @gol
+-Wno-format-contains-nul -Wno-format-extra-args -Wformat-nonliteral @gol
+-Wformat-security -Wformat-y2k @gol
+-Wframe-larger-than=@var{len} -Wignored-qualifiers @gol
+-Wimplicit -Wimplicit-function-declaration -Wimplicit-int @gol
+-Winit-self -Winline @gol
+-Wno-int-to-pointer-cast -Wno-invalid-offsetof @gol
+-Winvalid-pch -Wlarger-than=@var{len} -Wunsafe-loop-optimizations @gol
+-Wlogical-op -Wlong-long @gol
+-Wmain -Wmissing-braces -Wmissing-field-initializers @gol
+-Wmissing-format-attribute -Wmissing-include-dirs @gol
+-Wmissing-noreturn -Wno-mudflap @gol
+-Wno-multichar -Wnonnull -Wno-overflow @gol
+-Woverlength-strings -Wpacked -Wpacked-bitfield-compat -Wpadded @gol
+-Wparentheses -Wpedantic-ms-format -Wno-pedantic-ms-format @gol
+-Wpointer-arith -Wno-pointer-to-int-cast @gol
+-Wredundant-decls @gol
-Wreturn-type -Wsequence-point -Wshadow @gol
--Wsign-compare -Wswitch -Wsystem-headers @gol
--Wtrigraphs -Wundef -Wuninitialized @gol
--Wunknown-pragmas -Wunreachable-code @gol
+-Wsign-compare -Wsign-conversion -Wstack-protector @gol
+-Wstrict-aliasing -Wstrict-aliasing=n @gol
+-Wstrict-overflow -Wstrict-overflow=@var{n} @gol
+-Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol
+-Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol
+-Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol
-Wunused -Wunused-function -Wunused-label -Wunused-parameter @gol
--Wunused-value -Wunused-variable -Wwrite-strings}
+-Wunused-value -Wunused-variable @gol
+-Wvariadic-macros -Wvla @gol
+-Wvolatile-register-var -Wwrite-strings}
-@item C-only Warning Options
-@gccoptlist{
--Wbad-function-cast -Wmissing-declarations @gol
--Wmissing-prototypes -Wnested-externs @gol
--Wstrict-prototypes -Wtraditional}
+@item C and Objective-C-only Warning Options
+@gccoptlist{-Wbad-function-cast -Wmissing-declarations @gol
+-Wmissing-parameter-type -Wmissing-prototypes -Wnested-externs @gol
+-Wold-style-declaration -Wold-style-definition @gol
+-Wstrict-prototypes -Wtraditional -Wtraditional-conversion @gol
+-Wdeclaration-after-statement -Wpointer-sign}
@item Debugging Options
@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
-@gccoptlist{
--d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol
--fdump-unnumbered -fdump-translation-unit@r{[}-@var{n}@r{]} @gol
+@gccoptlist{-d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol
+-fdbg-cnt-list -fdbg-cnt=@var{counter-value-list} @gol
+-fdump-noaddr -fdump-unnumbered @gol
+-fdump-translation-unit@r{[}-@var{n}@r{]} @gol
-fdump-class-hierarchy@r{[}-@var{n}@r{]} @gol
--fdump-tree-original@r{[}-@var{n}@r{]} -fdump-tree-optimized@r{[}-@var{n}@r{]} @gol
--fdump-tree-inlined@r{[}-@var{n}@r{]} @gol
--fmem-report -fpretend-float @gol
--fprofile-arcs -fsched-verbose=@var{n} @gol
--ftest-coverage -ftime-report @gol
--g -g@var{level} -gcoff -gdwarf -gdwarf-1 -gdwarf-1+ -gdwarf-2 @gol
+-fdump-ipa-all -fdump-ipa-cgraph -fdump-ipa-inline @gol
+-fdump-statistics @gol
+-fdump-tree-all @gol
+-fdump-tree-original@r{[}-@var{n}@r{]} @gol
+-fdump-tree-optimized@r{[}-@var{n}@r{]} @gol
+-fdump-tree-cfg -fdump-tree-vcg -fdump-tree-alias @gol
+-fdump-tree-ch @gol
+-fdump-tree-ssa@r{[}-@var{n}@r{]} -fdump-tree-pre@r{[}-@var{n}@r{]} @gol
+-fdump-tree-ccp@r{[}-@var{n}@r{]} -fdump-tree-dce@r{[}-@var{n}@r{]} @gol
+-fdump-tree-gimple@r{[}-raw@r{]} -fdump-tree-mudflap@r{[}-@var{n}@r{]} @gol
+-fdump-tree-dom@r{[}-@var{n}@r{]} @gol
+-fdump-tree-dse@r{[}-@var{n}@r{]} @gol
+-fdump-tree-phiopt@r{[}-@var{n}@r{]} @gol
+-fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
+-fdump-tree-copyrename@r{[}-@var{n}@r{]} @gol
+-fdump-tree-nrv -fdump-tree-vect @gol
+-fdump-tree-sink @gol
+-fdump-tree-sra@r{[}-@var{n}@r{]} @gol
+-fdump-tree-fre@r{[}-@var{n}@r{]} @gol
+-fdump-tree-vrp@r{[}-@var{n}@r{]} @gol
+-ftree-vectorizer-verbose=@var{n} @gol
+-fdump-tree-storeccp@r{[}-@var{n}@r{]} @gol
+-feliminate-dwarf2-dups -feliminate-unused-debug-types @gol
+-feliminate-unused-debug-symbols -femit-class-debug-always @gol
+-fmem-report -fpre-ipa-mem-report -fpost-ipa-mem-report -fprofile-arcs @gol
+-frandom-seed=@var{string} -fsched-verbose=@var{n} @gol
+-fsel-sched-verbose -fsel-sched-dump-cfg -fsel-sched-pipelining-verbose @gol
+-ftest-coverage -ftime-report -fvar-tracking @gol
+-g -g@var{level} -gcoff -gdwarf-2 @gol
-ggdb -gstabs -gstabs+ -gvms -gxcoff -gxcoff+ @gol
+-fno-merge-debug-strings -fno-dwarf2-cfi-asm @gol
+-fdebug-prefix-map=@var{old}=@var{new} @gol
+-femit-struct-debug-baseonly -femit-struct-debug-reduced @gol
+-femit-struct-debug-detailed@r{[}=@var{spec-list}@r{]} @gol
-p -pg -print-file-name=@var{library} -print-libgcc-file-name @gol
-print-multi-directory -print-multi-lib @gol
-print-prog-name=@var{program} -print-search-dirs -Q @gol
+-print-sysroot -print-sysroot-headers-suffix @gol
-save-temps -time}
@item Optimization Options
@xref{Optimize Options,,Options that Control Optimization}.
@gccoptlist{
--falign-functions=@var{n} -falign-jumps=@var{n} @gol
--falign-labels=@var{n} -falign-loops=@var{n} @gol
--fbounds-check @gol
--fbranch-probabilities -fcaller-saves -fcprop-registers @gol
--fcse-follow-jumps -fcse-skip-blocks -fdata-sections @gol
--fdelayed-branch -fdelete-null-pointer-checks @gol
--fexpensive-optimizations -ffast-math -ffloat-store @gol
--fforce-addr -fforce-mem -ffunction-sections @gol
--fgcse -fgcse-lm -fgcse-sm @gol
--finline-functions -finline-limit=@var{n} -fkeep-inline-functions @gol
--fkeep-static-consts -fmerge-constants -fmerge-all-constants @gol
--fmove-all-movables -fno-branch-count-reg @gol
--fno-default-inline -fno-defer-pop @gol
--fno-function-cse -fno-guess-branch-probability @gol
--fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol
--funsafe-math-optimizations -fno-trapping-math @gol
--fomit-frame-pointer -foptimize-register-move @gol
--foptimize-sibling-calls -fprefetch-loop-arrays @gol
--freduce-all-givs -fregmove -frename-registers @gol
--frerun-cse-after-loop -frerun-loop-opt @gol
--fschedule-insns -fschedule-insns2 @gol
--fno-sched-interblock -fno-sched-spec @gol
--fsched-spec-load -fsched-spec-load-dangerous @gol
--fsingle-precision-constant -fssa -fssa-ccp -fssa-dce @gol
--fstrength-reduce -fstrict-aliasing -fthread-jumps @gol
--ftrapv -funroll-all-loops -funroll-loops @gol
+-falign-functions[=@var{n}] -falign-jumps[=@var{n}] @gol
+-falign-labels[=@var{n}] -falign-loops[=@var{n}] -fassociative-math @gol
+-fauto-inc-dec -fbranch-probabilities -fbranch-target-load-optimize @gol
+-fbranch-target-load-optimize2 -fbtr-bb-exclusive -fcaller-saves @gol
+-fcheck-data-deps -fconserve-stack -fcprop-registers -fcrossjumping @gol
+-fcse-follow-jumps -fcse-skip-blocks -fcx-fortran-rules -fcx-limited-range @gol
+-fdata-sections -fdce -fdce @gol
+-fdelayed-branch -fdelete-null-pointer-checks -fdse -fdse @gol
+-fearly-inlining -fexpensive-optimizations -ffast-math @gol
+-ffinite-math-only -ffloat-store -fforward-propagate @gol
+-ffunction-sections -fgcse -fgcse-after-reload -fgcse-las -fgcse-lm @gol
+-fgcse-sm -fif-conversion -fif-conversion2 -findirect-inlining @gol
+-finline-functions -finline-functions-called-once -finline-limit=@var{n} @gol
+-finline-small-functions -fipa-cp -fipa-cp-clone -fipa-matrix-reorg -fipa-pta @gol
+-fipa-pure-const -fipa-reference -fipa-struct-reorg @gol
+-fipa-type-escape -fira-algorithm=@var{algorithm} @gol
+-fira-region=@var{region} -fira-coalesce -fno-ira-share-save-slots @gol
+-fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
+-fivopts -fkeep-inline-functions -fkeep-static-consts @gol
+-floop-block -floop-interchange -floop-strip-mine @gol
+-fmerge-all-constants -fmerge-constants -fmodulo-sched @gol
+-fmodulo-sched-allow-regmoves -fmove-loop-invariants -fmudflap @gol
+-fmudflapir -fmudflapth -fno-branch-count-reg -fno-default-inline @gol
+-fno-defer-pop -fno-function-cse -fno-guess-branch-probability @gol
+-fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol
+-fno-sched-interblock -fno-sched-spec -fno-signed-zeros @gol
+-fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol
+-fomit-frame-pointer -foptimize-register-move -foptimize-sibling-calls @gol
+-fpeel-loops -fpredictive-commoning -fprefetch-loop-arrays @gol
+-fprofile-correction -fprofile-dir=@var{path} -fprofile-generate @gol
+-fprofile-generate=@var{path} @gol
+-fprofile-use -fprofile-use=@var{path} -fprofile-values @gol
+-freciprocal-math -fregmove -frename-registers -freorder-blocks @gol
+-freorder-blocks-and-partition -freorder-functions @gol
+-frerun-cse-after-loop -freschedule-modulo-scheduled-loops @gol
+-frounding-math -frtl-abstract-sequences -fsched2-use-superblocks @gol
+-fsched2-use-traces -fsched-spec-load -fsched-spec-load-dangerous @gol
+-fsched-stalled-insns-dep[=@var{n}] -fsched-stalled-insns[=@var{n}] @gol
+-fschedule-insns -fschedule-insns2 -fsection-anchors -fsee @gol
+-fselective-scheduling -fselective-scheduling2 @gol
+-fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
+-fsignaling-nans -fsingle-precision-constant -fsplit-ivs-in-unroller @gol
+-fsplit-wide-types -fstack-protector -fstack-protector-all @gol
+-fstrict-aliasing -fstrict-overflow -fthread-jumps -ftracer @gol
+-ftree-builtin-call-dce -ftree-ccp -ftree-ch -ftree-copy-prop @gol
+-ftree-copyrename -ftree-dce @gol
+-ftree-dominator-opts -ftree-dse -ftree-fre -ftree-loop-im @gol
+-ftree-loop-distribution @gol
+-ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
+-ftree-parallelize-loops=@var{n} -ftree-pre -ftree-reassoc @gol
+-ftree-sink -ftree-sra -ftree-switch-conversion @gol
+-ftree-ter -ftree-vect-loop-version -ftree-vectorize -ftree-vrp @gol
+-funit-at-a-time -funroll-all-loops -funroll-loops @gol
+-funsafe-loop-optimizations -funsafe-math-optimizations -funswitch-loops @gol
+-fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
+-fwhole-program @gol
--param @var{name}=@var{value}
-O -O0 -O1 -O2 -O3 -Os}
@item Preprocessor Options
@xref{Preprocessor Options,,Options Controlling the Preprocessor}.
-@gccoptlist{
--$ -A@var{question}=@var{answer} -A-@var{question}@r{[}=@var{answer}@r{]} @gol
+@gccoptlist{-A@var{question}=@var{answer} @gol
+-A-@var{question}@r{[}=@var{answer}@r{]} @gol
-C -dD -dI -dM -dN @gol
-D@var{macro}@r{[}=@var{defn}@r{]} -E -H @gol
-idirafter @var{dir} @gol
-include @var{file} -imacros @var{file} @gol
-iprefix @var{file} -iwithprefix @var{dir} @gol
-iwithprefixbefore @var{dir} -isystem @var{dir} @gol
--M -MM -MF -MG -MP -MQ -MT -nostdinc -P -remap @gol
--trigraphs -undef -U@var{macro} -Wp,@var{option}}
+-imultilib @var{dir} -isysroot @var{dir} @gol
+-M -MM -MF -MG -MP -MQ -MT -nostdinc @gol
+-P -fworking-directory -remap @gol
+-trigraphs -undef -U@var{macro} -Wp,@var{option} @gol
+-Xpreprocessor @var{option}}
@item Assembler Option
@xref{Assembler Options,,Passing Options to the Assembler}.
-@gccoptlist{
--Wa,@var{option}}
+@gccoptlist{-Wa,@var{option} -Xassembler @var{option}}
@item Linker Options
@xref{Link Options,,Options for Linking}.
-@gccoptlist{
-@var{object-file-name} -l@var{library} @gol
--nostartfiles -nodefaultlibs -nostdlib @gol
+@gccoptlist{@var{object-file-name} -l@var{library} @gol
+-nostartfiles -nodefaultlibs -nostdlib -pie -rdynamic @gol
-s -static -static-libgcc -shared -shared-libgcc -symbolic @gol
--Wl,@var{option} -Xlinker @var{option} @gol
+-T @var{script} -Wl,@var{option} -Xlinker @var{option} @gol
-u @var{symbol}}
@item Directory Options
@xref{Directory Options,,Options for Directory Search}.
-@gccoptlist{
--B@var{prefix} -I@var{dir} -I- -L@var{dir} -specs=@var{file}}
+@gccoptlist{-B@var{prefix} -I@var{dir} -iquote@var{dir} -L@var{dir}
+-specs=@var{file} -I- --sysroot=@var{dir}}
@item Target Options
@c I wrote this xref this way to avoid overfull hbox. -- rms
@xref{Target Options}.
-@gccoptlist{
--b @var{machine} -V @var{version}}
+@gccoptlist{-V @var{version} -b @var{machine}}
@item Machine Dependent Options
@xref{Submodel Options,,Hardware Models and Configurations}.
+@c This list is ordered alphanumerically by subsection name.
+@c Try and put the significant identifier (CPU or system) first,
+@c so users have a clue at guessing where the ones they want will be.
-@emph{M680x0 Options}
-@gccoptlist{
--m68000 -m68020 -m68020-40 -m68020-60 -m68030 -m68040 @gol
--m68060 -mcpu32 -m5200 -m68881 -mbitfield -mc68000 -mc68020 @gol
--mfpa -mnobitfield -mrtd -mshort -msoft-float -mpcrel @gol
--malign-int -mstrict-align}
-
-@emph{M68hc1x Options}
-@gccoptlist{
--m6811 -m6812 -m68hc11 -m68hc12 @gol
--mauto-incdec -mshort -msoft-reg-count=@var{count}}
-
-@emph{VAX Options}
-@gccoptlist{
--mg -mgnu -munix}
-
-@emph{SPARC Options}
-@gccoptlist{
--mcpu=@var{cpu-type} @gol
--mtune=@var{cpu-type} @gol
--mcmodel=@var{code-model} @gol
--m32 -m64 @gol
--mapp-regs -mbroken-saverestore -mcypress @gol
--mfaster-structs -mflat @gol
--mfpu -mhard-float -mhard-quad-float @gol
--mimpure-text -mlive-g0 -mno-app-regs @gol
--mno-faster-structs -mno-flat -mno-fpu @gol
--mno-impure-text -mno-stack-bias -mno-unaligned-doubles @gol
--msoft-float -msoft-quad-float -msparclite -mstack-bias @gol
--msupersparc -munaligned-doubles -mv8}
-
-@emph{Convex Options}
-@gccoptlist{
--mc1 -mc2 -mc32 -mc34 -mc38 @gol
--margcount -mnoargcount @gol
--mlong32 -mlong64 @gol
--mvolatile-cache -mvolatile-nocache}
-
-@emph{AMD29K Options}
-@gccoptlist{
--m29000 -m29050 -mbw -mnbw -mdw -mndw @gol
--mlarge -mnormal -msmall @gol
--mkernel-registers -mno-reuse-arg-regs @gol
--mno-stack-check -mno-storem-bug @gol
--mreuse-arg-regs -msoft-float -mstack-check @gol
--mstorem-bug -muser-registers}
+@emph{ARC Options}
+@gccoptlist{-EB -EL @gol
+-mmangle-cpu -mcpu=@var{cpu} -mtext=@var{text-section} @gol
+-mdata=@var{data-section} -mrodata=@var{readonly-data-section}}
@emph{ARM Options}
-@gccoptlist{
--mapcs-frame -mno-apcs-frame @gol
--mapcs-26 -mapcs-32 @gol
+@gccoptlist{-mapcs-frame -mno-apcs-frame @gol
+-mabi=@var{name} @gol
-mapcs-stack-check -mno-apcs-stack-check @gol
-mapcs-float -mno-apcs-float @gol
-mapcs-reentrant -mno-apcs-reentrant @gol
-msched-prolog -mno-sched-prolog @gol
-mlittle-endian -mbig-endian -mwords-little-endian @gol
--malignment-traps -mno-alignment-traps @gol
--msoft-float -mhard-float -mfpe @gol
+-mfloat-abi=@var{name} -msoft-float -mhard-float -mfpe @gol
-mthumb-interwork -mno-thumb-interwork @gol
--mcpu=@var{name} -march=@var{name} -mfpe=@var{name} @gol
+-mcpu=@var{name} -march=@var{name} -mfpu=@var{name} @gol
-mstructure-size-boundary=@var{n} @gol
--mbsd -mxopen -mno-symrename @gol
-mabort-on-noreturn @gol
-mlong-calls -mno-long-calls @gol
-msingle-pic-base -mno-single-pic-base @gol
-mpic-register=@var{reg} @gol
-mnop-fun-dllimport @gol
+-mcirrus-fix-invalid-insns -mno-cirrus-fix-invalid-insns @gol
-mpoke-function-name @gol
-mthumb -marm @gol
-mtpcs-frame -mtpcs-leaf-frame @gol
--mcaller-super-interworking -mcallee-super-interworking }
-
-@emph{MN10200 Options}
-@gccoptlist{
--mrelax}
-
-@emph{MN10300 Options}
-@gccoptlist{
--mmult-bug -mno-mult-bug @gol
--mam33 -mno-am33 @gol
--mno-crt0 -mrelax}
-
-@emph{M32R/D Options}
-@gccoptlist{
--m32rx -m32r -mcode-model=@var{model-type} -msdata=@var{sdata-type} @gol
--G @var{num}}
-
-@emph{M88K Options}
-@gccoptlist{
--m88000 -m88100 -m88110 -mbig-pic @gol
--mcheck-zero-division -mhandle-large-shift @gol
--midentify-revision -mno-check-zero-division @gol
--mno-ocs-debug-info -mno-ocs-frame-position @gol
--mno-optimize-arg-area -mno-serialize-volatile @gol
--mno-underscores -mocs-debug-info @gol
--mocs-frame-position -moptimize-arg-area @gol
--mserialize-volatile -mshort-data-@var{num} -msvr3 @gol
--msvr4 -mtrap-large-shift -muse-div-instruction @gol
--mversion-03.00 -mwarn-passed-structs}
-
-@emph{RS/6000 and PowerPC Options}
-@gccoptlist{
--mcpu=@var{cpu-type} @gol
--mtune=@var{cpu-type} @gol
--mpower -mno-power -mpower2 -mno-power2 @gol
--mpowerpc -mpowerpc64 -mno-powerpc @gol
--maltivec -mno-altivec @gol
--mpowerpc-gpopt -mno-powerpc-gpopt @gol
--mpowerpc-gfxopt -mno-powerpc-gfxopt @gol
--mnew-mnemonics -mold-mnemonics @gol
--mfull-toc -mminimal-toc -mno-fp-in-toc -mno-sum-in-toc @gol
--m64 -m32 -mxl-call -mno-xl-call -mpe @gol
--msoft-float -mhard-float -mmultiple -mno-multiple @gol
--mstring -mno-string -mupdate -mno-update @gol
--mfused-madd -mno-fused-madd -mbit-align -mno-bit-align @gol
--mstrict-align -mno-strict-align -mrelocatable @gol
--mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol
--mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol
--mcall-aix -mcall-sysv -mcall-netbsd @gol
--maix-struct-return -msvr4-struct-return @gol
--mabi=altivec -mabi=no-altivec @gol
--mprototype -mno-prototype @gol
--msim -mmvme -mads -myellowknife -memb -msdata @gol
--msdata=@var{opt} -mvxworks -G @var{num} -pthread}
-
-@emph{RT Options}
-@gccoptlist{
--mcall-lib-mul -mfp-arg-in-fpregs -mfp-arg-in-gregs @gol
--mfull-fp-blocks -mhc-struct-return -min-line-mul @gol
--mminimum-fp-blocks -mnohc-struct-return}
-
-@emph{MIPS Options}
-@gccoptlist{
--mabicalls -march=@var{cpu-type} -mtune=@var{cpu=type} @gol
--mcpu=@var{cpu-type} -membedded-data -muninit-const-in-rodata @gol
--membedded-pic -mfp32 -mfp64 -mfused-madd -mno-fused-madd @gol
--mgas -mgp32 -mgp64 @gol
--mgpopt -mhalf-pic -mhard-float -mint64 -mips1 @gol
--mips2 -mips3 -mips4 -mlong64 -mlong32 -mlong-calls -mmemcpy @gol
--mmips-as -mmips-tfile -mno-abicalls @gol
--mno-embedded-data -mno-uninit-const-in-rodata @gol
--mno-embedded-pic -mno-gpopt -mno-long-calls @gol
--mno-memcpy -mno-mips-tfile -mno-rnames -mno-stats @gol
--mrnames -msoft-float @gol
--m4650 -msingle-float -mmad @gol
--mstats -EL -EB -G @var{num} -nocpp @gol
--mabi=32 -mabi=n32 -mabi=64 -mabi=eabi @gol
--mfix7000 -mno-crt0 -mflush-func=@var{func} -mno-flush-func}
-
-@emph{i386 and x86-64 Options}
-@gccoptlist{
--mcpu=@var{cpu-type} -march=@var{cpu-type} -mfpmath=@var{unit} @gol
--masm=@var{dialect} -mno-fancy-math-387 @gol
--mno-fp-ret-in-387 -msoft-float -msvr3-shlib @gol
--mno-wide-multiply -mrtd -malign-double @gol
--mpreferred-stack-boundary=@var{num} @gol
--mmmx -msse -msse2 -m3dnow @gol
--mthreads -mno-align-stringops -minline-all-stringops @gol
--mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol
--m96bit-long-double -mregparm=@var{num} -momit-leaf-frame-pointer @gol
--mno-red-zone@gol
--mcmodel=@var{code-model} @gol
--m32 -m64}
+-mcaller-super-interworking -mcallee-super-interworking @gol
+-mtp=@var{name} @gol
+-mword-relocations @gol
+-mfix-cortex-m3-ldrd}
-@emph{HPPA Options}
-@gccoptlist{
--march=@var{architecture-type} @gol
--mbig-switch -mdisable-fpregs -mdisable-indexing @gol
--mfast-indirect-calls -mgas -mjump-in-delay @gol
--mlong-load-store -mno-big-switch -mno-disable-fpregs @gol
--mno-disable-indexing -mno-fast-indirect-calls -mno-gas @gol
--mno-jump-in-delay -mno-long-load-store @gol
--mno-portable-runtime -mno-soft-float @gol
--mno-space-regs -msoft-float -mpa-risc-1-0 @gol
--mpa-risc-1-1 -mpa-risc-2-0 -mportable-runtime @gol
--mschedule=@var{cpu-type} -mspace-regs}
+@emph{AVR Options}
+@gccoptlist{-mmcu=@var{mcu} -msize -mno-interrupts @gol
+-mcall-prologues -mno-tablejump -mtiny-stack -mint8}
+
+@emph{Blackfin Options}
+@gccoptlist{-mcpu=@var{cpu}@r{[}-@var{sirevision}@r{]} @gol
+-msim -momit-leaf-frame-pointer -mno-omit-leaf-frame-pointer @gol
+-mspecld-anomaly -mno-specld-anomaly -mcsync-anomaly -mno-csync-anomaly @gol
+-mlow-64k -mno-low64k -mstack-check-l1 -mid-shared-library @gol
+-mno-id-shared-library -mshared-library-id=@var{n} @gol
+-mleaf-id-shared-library -mno-leaf-id-shared-library @gol
+-msep-data -mno-sep-data -mlong-calls -mno-long-calls @gol
+-mfast-fp -minline-plt -mmulticore -mcorea -mcoreb -msdram @gol
+-micplb}
-@emph{Intel 960 Options}
-@gccoptlist{
--m@var{cpu-type} -masm-compat -mclean-linkage @gol
--mcode-align -mcomplex-addr -mleaf-procedures @gol
--mic-compat -mic2.0-compat -mic3.0-compat @gol
--mintel-asm -mno-clean-linkage -mno-code-align @gol
--mno-complex-addr -mno-leaf-procedures @gol
--mno-old-align -mno-strict-align -mno-tail-call @gol
--mnumerics -mold-align -msoft-float -mstrict-align @gol
--mtail-call}
+@emph{CRIS Options}
+@gccoptlist{-mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol
+-mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol
+-metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol
+-mstack-align -mdata-align -mconst-align @gol
+-m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol
+-melf -maout -melinux -mlinux -sim -sim2 @gol
+-mmul-bug-workaround -mno-mul-bug-workaround}
+
+@emph{CRX Options}
+@gccoptlist{-mmac -mpush-args}
+
+@emph{Darwin Options}
+@gccoptlist{-all_load -allowable_client -arch -arch_errors_fatal @gol
+-arch_only -bind_at_load -bundle -bundle_loader @gol
+-client_name -compatibility_version -current_version @gol
+-dead_strip @gol
+-dependency-file -dylib_file -dylinker_install_name @gol
+-dynamic -dynamiclib -exported_symbols_list @gol
+-filelist -flat_namespace -force_cpusubtype_ALL @gol
+-force_flat_namespace -headerpad_max_install_names @gol
+-iframework @gol
+-image_base -init -install_name -keep_private_externs @gol
+-multi_module -multiply_defined -multiply_defined_unused @gol
+-noall_load -no_dead_strip_inits_and_terms @gol
+-nofixprebinding -nomultidefs -noprebind -noseglinkedit @gol
+-pagezero_size -prebind -prebind_all_twolevel_modules @gol
+-private_bundle -read_only_relocs -sectalign @gol
+-sectobjectsymbols -whyload -seg1addr @gol
+-sectcreate -sectobjectsymbols -sectorder @gol
+-segaddr -segs_read_only_addr -segs_read_write_addr @gol
+-seg_addr_table -seg_addr_table_filename -seglinkedit @gol
+-segprot -segs_read_only_addr -segs_read_write_addr @gol
+-single_module -static -sub_library -sub_umbrella @gol
+-twolevel_namespace -umbrella -undefined @gol
+-unexported_symbols_list -weak_reference_mismatches @gol
+-whatsloaded -F -gused -gfull -mmacosx-version-min=@var{version} @gol
+-mkernel -mone-byte-bool}
@emph{DEC Alpha Options}
-@gccoptlist{
--mno-fp-regs -msoft-float -malpha-as -mgas @gol
+@gccoptlist{-mno-fp-regs -msoft-float -malpha-as -mgas @gol
-mieee -mieee-with-inexact -mieee-conformant @gol
-mfp-trap-mode=@var{mode} -mfp-rounding-mode=@var{mode} @gol
-mtrap-precision=@var{mode} -mbuild-constants @gol
-mbwx -mmax -mfix -mcix @gol
-mfloat-vax -mfloat-ieee @gol
-mexplicit-relocs -msmall-data -mlarge-data @gol
+-msmall-text -mlarge-text @gol
-mmemory-latency=@var{time}}
@emph{DEC Alpha/VMS Options}
-@gccoptlist{
--mvms-return-codes}
-
-@emph{Clipper Options}
-@gccoptlist{
--mc300 -mc400}
+@gccoptlist{-mvms-return-codes}
+
+@emph{FR30 Options}
+@gccoptlist{-msmall-model -mno-lsim}
+
+@emph{FRV Options}
+@gccoptlist{-mgpr-32 -mgpr-64 -mfpr-32 -mfpr-64 @gol
+-mhard-float -msoft-float @gol
+-malloc-cc -mfixed-cc -mdword -mno-dword @gol
+-mdouble -mno-double @gol
+-mmedia -mno-media -mmuladd -mno-muladd @gol
+-mfdpic -minline-plt -mgprel-ro -multilib-library-pic @gol
+-mlinked-fp -mlong-calls -malign-labels @gol
+-mlibrary-pic -macc-4 -macc-8 @gol
+-mpack -mno-pack -mno-eflags -mcond-move -mno-cond-move @gol
+-moptimize-membar -mno-optimize-membar @gol
+-mscc -mno-scc -mcond-exec -mno-cond-exec @gol
+-mvliw-branch -mno-vliw-branch @gol
+-mmulti-cond-exec -mno-multi-cond-exec -mnested-cond-exec @gol
+-mno-nested-cond-exec -mtomcat-stats @gol
+-mTLS -mtls @gol
+-mcpu=@var{cpu}}
+
+@emph{GNU/Linux Options}
+@gccoptlist{-muclibc}
@emph{H8/300 Options}
-@gccoptlist{
--mrelax -mh -ms -mint32 -malign-300}
+@gccoptlist{-mrelax -mh -ms -mn -mint32 -malign-300}
-@emph{SH Options}
-@gccoptlist{
--m1 -m2 -m3 -m3e @gol
--m4-nofpu -m4-single-only -m4-single -m4 @gol
--m5-64media -m5-64media-nofpu @gol
--m5-32media -m5-32media-nofpu @gol
--m5-compact -m5-compact-nofpu @gol
--mb -ml -mdalign -mrelax @gol
--mbigtable -mfmovd -mhitachi -mnomacsave @gol
--mieee -misize -mpadstruct -mspace @gol
--mprefergot -musermode}
+@emph{HPPA Options}
+@gccoptlist{-march=@var{architecture-type} @gol
+-mbig-switch -mdisable-fpregs -mdisable-indexing @gol
+-mfast-indirect-calls -mgas -mgnu-ld -mhp-ld @gol
+-mfixed-range=@var{register-range} @gol
+-mjump-in-delay -mlinker-opt -mlong-calls @gol
+-mlong-load-store -mno-big-switch -mno-disable-fpregs @gol
+-mno-disable-indexing -mno-fast-indirect-calls -mno-gas @gol
+-mno-jump-in-delay -mno-long-load-store @gol
+-mno-portable-runtime -mno-soft-float @gol
+-mno-space-regs -msoft-float -mpa-risc-1-0 @gol
+-mpa-risc-1-1 -mpa-risc-2-0 -mportable-runtime @gol
+-mschedule=@var{cpu-type} -mspace-regs -msio -mwsio @gol
+-munix=@var{unix-std} -nolibdld -static -threads}
-@emph{System V Options}
-@gccoptlist{
--Qy -Qn -YP,@var{paths} -Ym,@var{dir}}
+@emph{i386 and x86-64 Options}
+@gccoptlist{-mtune=@var{cpu-type} -march=@var{cpu-type} @gol
+-mfpmath=@var{unit} @gol
+-masm=@var{dialect} -mno-fancy-math-387 @gol
+-mno-fp-ret-in-387 -msoft-float @gol
+-mno-wide-multiply -mrtd -malign-double @gol
+-mpreferred-stack-boundary=@var{num}
+-mincoming-stack-boundary=@var{num}
+-mcld -mcx16 -msahf -mrecip @gol
+-mmmx -msse -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -msse4 -mavx @gol
+-maes -mpclmul @gol
+-msse4a -m3dnow -mpopcnt -mabm -msse5 @gol
+-mthreads -mno-align-stringops -minline-all-stringops @gol
+-minline-stringops-dynamically -mstringop-strategy=@var{alg} @gol
+-mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol
+-m96bit-long-double -mregparm=@var{num} -msseregparm @gol
+-mveclibabi=@var{type} -mpc32 -mpc64 -mpc80 -mstackrealign @gol
+-momit-leaf-frame-pointer -mno-red-zone -mno-tls-direct-seg-refs @gol
+-mcmodel=@var{code-model} @gol
+-m32 -m64 -mlarge-data-threshold=@var{num} @gol
+-mfused-madd -mno-fused-madd -msse2avx}
-@emph{ARC Options}
-@gccoptlist{
--EB -EL @gol
--mmangle-cpu -mcpu=@var{cpu} -mtext=@var{text-section} @gol
--mdata=@var{data-section} -mrodata=@var{readonly-data-section}}
+@emph{IA-64 Options}
+@gccoptlist{-mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol
+-mvolatile-asm-stop -mregister-names -mno-sdata @gol
+-mconstant-gp -mauto-pic -minline-float-divide-min-latency @gol
+-minline-float-divide-max-throughput @gol
+-minline-int-divide-min-latency @gol
+-minline-int-divide-max-throughput @gol
+-minline-sqrt-min-latency -minline-sqrt-max-throughput @gol
+-mno-dwarf2-asm -mearly-stop-bits @gol
+-mfixed-range=@var{register-range} -mtls-size=@var{tls-size} @gol
+-mtune=@var{cpu-type} -mt -pthread -milp32 -mlp64 @gol
+-mno-sched-br-data-spec -msched-ar-data-spec -mno-sched-control-spec @gol
+-msched-br-in-data-spec -msched-ar-in-data-spec -msched-in-control-spec @gol
+-msched-ldc -mno-sched-control-ldc -mno-sched-spec-verbose @gol
+-mno-sched-prefer-non-data-spec-insns @gol
+-mno-sched-prefer-non-control-spec-insns @gol
+-mno-sched-count-spec-in-critical-path}
-@emph{TMS320C3x/C4x Options}
-@gccoptlist{
--mcpu=@var{cpu} -mbig -msmall -mregparm -mmemparm @gol
--mfast-fix -mmpyi -mbk -mti -mdp-isr-reload @gol
--mrpts=@var{count} -mrptb -mdb -mloop-unsigned @gol
--mparallel-insns -mparallel-mpy -mpreserve-float}
+@emph{M32R/D Options}
+@gccoptlist{-m32r2 -m32rx -m32r @gol
+-mdebug @gol
+-malign-loops -mno-align-loops @gol
+-missue-rate=@var{number} @gol
+-mbranch-cost=@var{number} @gol
+-mmodel=@var{code-size-model-type} @gol
+-msdata=@var{sdata-type} @gol
+-mno-flush-func -mflush-func=@var{name} @gol
+-mno-flush-trap -mflush-trap=@var{number} @gol
+-G @var{num}}
-@emph{V850 Options}
-@gccoptlist{
--mlong-calls -mno-long-calls -mep -mno-ep @gol
--mprolog-function -mno-prolog-function -mspace @gol
--mtda=@var{n} -msda=@var{n} -mzda=@var{n} @gol
--mv850 -mbig-switch}
+@emph{M32C Options}
+@gccoptlist{-mcpu=@var{cpu} -msim -memregs=@var{number}}
-@emph{NS32K Options}
-@gccoptlist{
--m32032 -m32332 -m32532 -m32081 -m32381 @gol
--mmult-add -mnomult-add -msoft-float -mrtd -mnortd @gol
--mregparam -mnoregparam -msb -mnosb @gol
--mbitfield -mnobitfield -mhimem -mnohimem}
+@emph{M680x0 Options}
+@gccoptlist{-march=@var{arch} -mcpu=@var{cpu} -mtune=@var{tune}
+-m68000 -m68020 -m68020-40 -m68020-60 -m68030 -m68040 @gol
+-m68060 -mcpu32 -m5200 -m5206e -m528x -m5307 -m5407 @gol
+-mcfv4e -mbitfield -mno-bitfield -mc68000 -mc68020 @gol
+-mnobitfield -mrtd -mno-rtd -mdiv -mno-div -mshort @gol
+-mno-short -mhard-float -m68881 -msoft-float -mpcrel @gol
+-malign-int -mstrict-align -msep-data -mno-sep-data @gol
+-mshared-library-id=n -mid-shared-library -mno-id-shared-library @gol
+-mxgot -mno-xgot}
-@emph{AVR Options}
-@gccoptlist{
--mmcu=@var{mcu} -msize -minit-stack=@var{n} -mno-interrupts @gol
--mcall-prologues -mno-tablejump -mtiny-stack}
+@emph{M68hc1x Options}
+@gccoptlist{-m6811 -m6812 -m68hc11 -m68hc12 -m68hcs12 @gol
+-mauto-incdec -minmax -mlong-calls -mshort @gol
+-msoft-reg-count=@var{count}}
@emph{MCore Options}
-@gccoptlist{
--mhardlit -mno-hardlit -mdiv -mno-div -mrelax-immediates @gol
+@gccoptlist{-mhardlit -mno-hardlit -mdiv -mno-div -mrelax-immediates @gol
-mno-relax-immediates -mwide-bitfields -mno-wide-bitfields @gol
-m4byte-functions -mno-4byte-functions -mcallgraph-data @gol
-mno-callgraph-data -mslow-bytes -mno-slow-bytes -mno-lsim @gol
-mlittle-endian -mbig-endian -m210 -m340 -mstack-increment}
-@emph{MMIX Options}
-@gccoptlist{
--mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
--mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol
--melf -mbranch-predict -mno-branch-predict -mbase-addresses @gol
--mno-base-addresses}
-
-@emph{IA-64 Options}
-@gccoptlist{
--mbig-endian -mlittle-endian -mgnu-as -mgnu-ld -mno-pic @gol
--mvolatile-asm-stop -mb-step -mregister-names -mno-sdata @gol
--mconstant-gp -mauto-pic -minline-divide-min-latency @gol
--minline-divide-max-throughput -mno-dwarf2-asm @gol
--mfixed-range=@var{register-range}}
-
-@emph{D30V Options}
-@gccoptlist{
--mextmem -mextmemory -monchip -mno-asm-optimize @gol
--masm-optimize -mbranch-cost=@var{n} -mcond-exec=@var{n}}
+@emph{MIPS Options}
+@gccoptlist{-EL -EB -march=@var{arch} -mtune=@var{arch} @gol
+-mips1 -mips2 -mips3 -mips4 -mips32 -mips32r2 @gol
+-mips64 -mips64r2 @gol
+-mips16 -mno-mips16 -mflip-mips16 @gol
+-minterlink-mips16 -mno-interlink-mips16 @gol
+-mabi=@var{abi} -mabicalls -mno-abicalls @gol
+-mshared -mno-shared -mplt -mno-plt -mxgot -mno-xgot @gol
+-mgp32 -mgp64 -mfp32 -mfp64 -mhard-float -msoft-float @gol
+-msingle-float -mdouble-float -mdsp -mno-dsp -mdspr2 -mno-dspr2 @gol
+-mfpu=@var{fpu-type} @gol
+-msmartmips -mno-smartmips @gol
+-mpaired-single -mno-paired-single -mdmx -mno-mdmx @gol
+-mips3d -mno-mips3d -mmt -mno-mt -mllsc -mno-llsc @gol
+-mlong64 -mlong32 -msym32 -mno-sym32 @gol
+-G@var{num} -mlocal-sdata -mno-local-sdata @gol
+-mextern-sdata -mno-extern-sdata -mgpopt -mno-gopt @gol
+-membedded-data -mno-embedded-data @gol
+-muninit-const-in-rodata -mno-uninit-const-in-rodata @gol
+-mcode-readable=@var{setting} @gol
+-msplit-addresses -mno-split-addresses @gol
+-mexplicit-relocs -mno-explicit-relocs @gol
+-mcheck-zero-division -mno-check-zero-division @gol
+-mdivide-traps -mdivide-breaks @gol
+-mmemcpy -mno-memcpy -mlong-calls -mno-long-calls @gol
+-mmad -mno-mad -mfused-madd -mno-fused-madd -nocpp @gol
+-mfix-r4000 -mno-fix-r4000 -mfix-r4400 -mno-fix-r4400 @gol
+-mfix-r10000 -mno-fix-r10000 -mfix-vr4120 -mno-fix-vr4120 @gol
+-mfix-vr4130 -mno-fix-vr4130 -mfix-sb1 -mno-fix-sb1 @gol
+-mflush-func=@var{func} -mno-flush-func @gol
+-mbranch-cost=@var{num} -mbranch-likely -mno-branch-likely @gol
+-mfp-exceptions -mno-fp-exceptions @gol
+-mvr4130-align -mno-vr4130-align}
-@emph{S/390 and zSeries Options}
-@gccoptlist{
--mhard-float -msoft-float -mbackchain -mno-backchain @gol
--msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol
--m64 -m31 -mdebug -mno-debug}
+@emph{MMIX Options}
+@gccoptlist{-mlibfuncs -mno-libfuncs -mepsilon -mno-epsilon -mabi=gnu @gol
+-mabi=mmixware -mzero-extend -mknuthdiv -mtoplevel-symbols @gol
+-melf -mbranch-predict -mno-branch-predict -mbase-addresses @gol
+-mno-base-addresses -msingle-exit -mno-single-exit}
-@emph{CRIS Options}
-@gccoptlist{
--mcpu=@var{cpu} -march=@var{cpu} -mtune=@var{cpu} @gol
--mmax-stack-frame=@var{n} -melinux-stacksize=@var{n} @gol
--metrax4 -metrax100 -mpdebug -mcc-init -mno-side-effects @gol
--mstack-align -mdata-align -mconst-align @gol
--m32-bit -m16-bit -m8-bit -mno-prologue-epilogue -mno-gotplt @gol
--melf -maout -melinux -mlinux -sim -sim2}
+@emph{MN10300 Options}
+@gccoptlist{-mmult-bug -mno-mult-bug @gol
+-mam33 -mno-am33 @gol
+-mam33-2 -mno-am33-2 @gol
+-mreturn-pointer-on-d0 @gol
+-mno-crt0 -mrelax}
@emph{PDP-11 Options}
-@gccoptlist{
--mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 @gol
+@gccoptlist{-mfpu -msoft-float -mac0 -mno-ac0 -m40 -m45 -m10 @gol
-mbcopy -mbcopy-builtin -mint32 -mno-int16 @gol
-mint16 -mno-int32 -mfloat32 -mno-float64 @gol
-mfloat64 -mno-float32 -mabshi -mno-abshi @gol
-mbranch-expensive -mbranch-cheap @gol
-msplit -mno-split -munix-asm -mdec-asm}
+@emph{picoChip Options}
+@gccoptlist{-mae=@var{ae_type} -mvliw-lookahead=@var{N}
+-msymbol-as-address -mno-inefficient-warnings}
+
+@emph{PowerPC Options}
+See RS/6000 and PowerPC Options.
+
+@emph{RS/6000 and PowerPC Options}
+@gccoptlist{-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mpower -mno-power -mpower2 -mno-power2 @gol
+-mpowerpc -mpowerpc64 -mno-powerpc @gol
+-maltivec -mno-altivec @gol
+-mpowerpc-gpopt -mno-powerpc-gpopt @gol
+-mpowerpc-gfxopt -mno-powerpc-gfxopt @gol
+-mmfcrf -mno-mfcrf -mpopcntb -mno-popcntb -mfprnd -mno-fprnd @gol
+-mcmpb -mno-cmpb -mmfpgpr -mno-mfpgpr -mhard-dfp -mno-hard-dfp @gol
+-mnew-mnemonics -mold-mnemonics @gol
+-mfull-toc -mminimal-toc -mno-fp-in-toc -mno-sum-in-toc @gol
+-m64 -m32 -mxl-compat -mno-xl-compat -mpe @gol
+-malign-power -malign-natural @gol
+-msoft-float -mhard-float -mmultiple -mno-multiple @gol
+-msingle-float -mdouble-float -msimple-fpu @gol
+-mstring -mno-string -mupdate -mno-update @gol
+-mavoid-indexed-addresses -mno-avoid-indexed-addresses @gol
+-mfused-madd -mno-fused-madd -mbit-align -mno-bit-align @gol
+-mstrict-align -mno-strict-align -mrelocatable @gol
+-mno-relocatable -mrelocatable-lib -mno-relocatable-lib @gol
+-mtoc -mno-toc -mlittle -mlittle-endian -mbig -mbig-endian @gol
+-mdynamic-no-pic -maltivec -mswdiv @gol
+-mprioritize-restricted-insns=@var{priority} @gol
+-msched-costly-dep=@var{dependence_type} @gol
+-minsert-sched-nops=@var{scheme} @gol
+-mcall-sysv -mcall-netbsd @gol
+-maix-struct-return -msvr4-struct-return @gol
+-mabi=@var{abi-type} -msecure-plt -mbss-plt @gol
+-misel -mno-isel @gol
+-misel=yes -misel=no @gol
+-mspe -mno-spe @gol
+-mspe=yes -mspe=no @gol
+-mpaired @gol
+-mgen-cell-microcode -mwarn-cell-microcode @gol
+-mvrsave -mno-vrsave @gol
+-mmulhw -mno-mulhw @gol
+-mdlmzb -mno-dlmzb @gol
+-mfloat-gprs=yes -mfloat-gprs=no -mfloat-gprs=single -mfloat-gprs=double @gol
+-mprototype -mno-prototype @gol
+-msim -mmvme -mads -myellowknife -memb -msdata @gol
+-msdata=@var{opt} -mvxworks -G @var{num} -pthread}
+
+@emph{S/390 and zSeries Options}
+@gccoptlist{-mtune=@var{cpu-type} -march=@var{cpu-type} @gol
+-mhard-float -msoft-float -mhard-dfp -mno-hard-dfp @gol
+-mlong-double-64 -mlong-double-128 @gol
+-mbackchain -mno-backchain -mpacked-stack -mno-packed-stack @gol
+-msmall-exec -mno-small-exec -mmvcle -mno-mvcle @gol
+-m64 -m31 -mdebug -mno-debug -mesa -mzarch @gol
+-mtpf-trace -mno-tpf-trace -mfused-madd -mno-fused-madd @gol
+-mwarn-framesize -mwarn-dynamicstack -mstack-size -mstack-guard}
+
+@emph{Score Options}
+@gccoptlist{-meb -mel @gol
+-mnhwloop @gol
+-muls @gol
+-mmac @gol
+-mscore5 -mscore5u -mscore7 -mscore7d}
+
+@emph{SH Options}
+@gccoptlist{-m1 -m2 -m2e -m3 -m3e @gol
+-m4-nofpu -m4-single-only -m4-single -m4 @gol
+-m4a-nofpu -m4a-single-only -m4a-single -m4a -m4al @gol
+-m5-64media -m5-64media-nofpu @gol
+-m5-32media -m5-32media-nofpu @gol
+-m5-compact -m5-compact-nofpu @gol
+-mb -ml -mdalign -mrelax @gol
+-mbigtable -mfmovd -mhitachi -mrenesas -mno-renesas -mnomacsave @gol
+-mieee -mbitops -misize -minline-ic_invalidate -mpadstruct -mspace @gol
+-mprefergot -musermode -multcost=@var{number} -mdiv=@var{strategy} @gol
+-mdivsi3_libfunc=@var{name} -mfixed-range=@var{register-range} @gol
+-madjust-unroll -mindexed-addressing -mgettrcost=@var{number} -mpt-fixed @gol
+-minvalid-symbols}
+
+@emph{SPARC Options}
+@gccoptlist{-mcpu=@var{cpu-type} @gol
+-mtune=@var{cpu-type} @gol
+-mcmodel=@var{code-model} @gol
+-m32 -m64 -mapp-regs -mno-app-regs @gol
+-mfaster-structs -mno-faster-structs @gol
+-mfpu -mno-fpu -mhard-float -msoft-float @gol
+-mhard-quad-float -msoft-quad-float @gol
+-mimpure-text -mno-impure-text -mlittle-endian @gol
+-mstack-bias -mno-stack-bias @gol
+-munaligned-doubles -mno-unaligned-doubles @gol
+-mv8plus -mno-v8plus -mvis -mno-vis
+-threads -pthreads -pthread}
+
+@emph{SPU Options}
+@gccoptlist{-mwarn-reloc -merror-reloc @gol
+-msafe-dma -munsafe-dma @gol
+-mbranch-hints @gol
+-msmall-mem -mlarge-mem -mstdmain @gol
+-mfixed-range=@var{register-range}}
+
+@emph{System V Options}
+@gccoptlist{-Qy -Qn -YP,@var{paths} -Ym,@var{dir}}
+
+@emph{V850 Options}
+@gccoptlist{-mlong-calls -mno-long-calls -mep -mno-ep @gol
+-mprolog-function -mno-prolog-function -mspace @gol
+-mtda=@var{n} -msda=@var{n} -mzda=@var{n} @gol
+-mapp-regs -mno-app-regs @gol
+-mdisable-callt -mno-disable-callt @gol
+-mv850e1 @gol
+-mv850e @gol
+-mv850 -mbig-switch}
+
+@emph{VAX Options}
+@gccoptlist{-mg -mgnu -munix}
+
+@emph{VxWorks Options}
+@gccoptlist{-mrtp -non-static -Bstatic -Bdynamic @gol
+-Xbind-lazy -Xbind-now}
+
+@emph{x86-64 Options}
+See i386 and x86-64 Options.
+
+@emph{i386 and x86-64 Windows Options}
+@gccoptlist{-mconsole -mcygwin -mno-cygwin -mdll
+-mnop-fun-dllimport -mthread -mwin32 -mwindows}
+
@emph{Xstormy16 Options}
-@gccoptlist{
--msim}
+@gccoptlist{-msim}
@emph{Xtensa Options}
-@gccoptlist{
--mbig-endian -mlittle-endian @gol
--mdensity -mno-density @gol
--mmac16 -mno-mac16 @gol
--mmul16 -mno-mul16 @gol
--mmul32 -mno-mul32 @gol
--mnsa -mno-nsa @gol
--mminmax -mno-minmax @gol
--msext -mno-sext @gol
--mbooleans -mno-booleans @gol
--mhard-float -msoft-float @gol
--mfused-madd -mno-fused-madd @gol
--mserialize-volatile -mno-serialize-volatile @gol
--mtext-section-literals -mno-text-section-literals @gol
--mtarget-align -mno-target-align @gol
--mlongcalls -mno-longcalls}
+@gccoptlist{-mconst16 -mno-const16 @gol
+-mfused-madd -mno-fused-madd @gol
+-mserialize-volatile -mno-serialize-volatile @gol
+-mtext-section-literals -mno-text-section-literals @gol
+-mtarget-align -mno-target-align @gol
+-mlongcalls -mno-longcalls}
+
+@emph{zSeries Options}
+See S/390 and zSeries Options.
@item Code Generation Options
@xref{Code Gen Options,,Options for Code Generation Conventions}.
-@gccoptlist{
--fcall-saved-@var{reg} -fcall-used-@var{reg} @gol
--ffixed-@var{reg} -fexceptions @gol
+@gccoptlist{-fcall-saved-@var{reg} -fcall-used-@var{reg} @gol
+-ffixed-@var{reg} -fexceptions @gol
-fnon-call-exceptions -funwind-tables @gol
-fasynchronous-unwind-tables @gol
-finhibit-size-directive -finstrument-functions @gol
--fno-common -fno-ident -fno-gnu-linker @gol
--fpcc-struct-return -fpic -fPIC @gol
--freg-struct-return -fshared-data -fshort-enums @gol
--fshort-double -fshort-wchar -fvolatile @gol
--fvolatile-global -fvolatile-static @gol
--fverbose-asm -fpack-struct -fstack-check @gol
+-finstrument-functions-exclude-function-list=@var{sym},@var{sym},@dots{} @gol
+-finstrument-functions-exclude-file-list=@var{file},@var{file},@dots{} @gol
+-fno-common -fno-ident @gol
+-fpcc-struct-return -fpic -fPIC -fpie -fPIE @gol
+-fno-jump-tables @gol
+-frecord-gcc-switches @gol
+-freg-struct-return -fshort-enums @gol
+-fshort-double -fshort-wchar @gol
+-fverbose-asm -fpack-struct[=@var{n}] -fstack-check @gol
-fstack-limit-register=@var{reg} -fstack-limit-symbol=@var{sym} @gol
--fargument-alias -fargument-noalias @gol
--fargument-noalias-global -fleading-underscore}
+-fno-stack-limit -fargument-alias -fargument-noalias @gol
+-fargument-noalias-global -fargument-noalias-anything @gol
+-fleading-underscore -ftls-model=@var{model} @gol
+-ftrapv -fwrapv -fbounds-check @gol
+-fvisibility}
@end table
@menu
or preprocessed source.
* C Dialect Options:: Controlling the variant of C language compiled.
* C++ Dialect Options:: Variations on C++.
-* Objective-C Dialect Options:: Variations on Objective-C.
+* Objective-C and Objective-C++ Dialect Options:: Variations on Objective-C
+ and Objective-C++.
* Language Independent Options:: Controlling how diagnostics should be
formatted.
* Warning Options:: How picky should the compiler be?
@section Options Controlling the Kind of Output
Compilation can involve up to four stages: preprocessing, compilation
-proper, assembly and linking, always in that order. The first three
-stages apply to an individual source file, and end by producing an
-object file; linking combines all the object files (those newly
-compiled, and those specified as input) into an executable file.
+proper, assembly and linking, always in that order. GCC is capable of
+preprocessing and compiling several files either into several
+assembler input files, or into one assembler input file; then each
+assembler input file produces an object file, and linking combines all
+the object files (those newly compiled, and those specified as input)
+into an executable file.
@cindex file name suffix
For any given input file, the file name suffix determines what kind of
C++ source code which should not be preprocessed.
@item @var{file}.m
-Objective-C source code. Note that you must link with the library
-@file{libobjc.a} to make an Objective-C program work.
+Objective-C source code. Note that you must link with the @file{libobjc}
+library to make an Objective-C program work.
@item @var{file}.mi
Objective-C source code which should not be preprocessed.
+@item @var{file}.mm
+@itemx @var{file}.M
+Objective-C++ source code. Note that you must link with the @file{libobjc}
+library to make an Objective-C++ program work. Note that @samp{.M} refers
+to a literal capital M@.
+
+@item @var{file}.mii
+Objective-C++ source code which should not be preprocessed.
+
@item @var{file}.h
-C header file (not to be compiled or linked).
+C, C++, Objective-C or Objective-C++ header file to be turned into a
+precompiled header.
@item @var{file}.cc
@itemx @var{file}.cp
@itemx @var{file}.cxx
@itemx @var{file}.cpp
+@itemx @var{file}.CPP
@itemx @var{file}.c++
@itemx @var{file}.C
C++ source code which must be preprocessed. Note that in @samp{.cxx},
the last two letters must both be literally @samp{x}. Likewise,
@samp{.C} refers to a literal capital C@.
+@item @var{file}.mm
+@itemx @var{file}.M
+Objective-C++ source code which must be preprocessed.
+
+@item @var{file}.mii
+Objective-C++ source code which should not be preprocessed.
+
+@item @var{file}.hh
+@itemx @var{file}.H
+@itemx @var{file}.hp
+@itemx @var{file}.hxx
+@itemx @var{file}.hpp
+@itemx @var{file}.HPP
+@itemx @var{file}.h++
+@itemx @var{file}.tcc
+C++ header file to be turned into a precompiled header.
+
@item @var{file}.f
@itemx @var{file}.for
-@itemx @var{file}.FOR
-Fortran source code which should not be preprocessed.
+@itemx @var{file}.ftn
+Fixed form Fortran source code which should not be preprocessed.
@item @var{file}.F
+@itemx @var{file}.FOR
@itemx @var{file}.fpp
@itemx @var{file}.FPP
-Fortran source code which must be preprocessed (with the traditional
+@itemx @var{file}.FTN
+Fixed form Fortran source code which must be preprocessed (with the traditional
preprocessor).
-@item @var{file}.r
-Fortran source code which must be preprocessed with a RATFOR
-preprocessor (not included with GCC)@.
+@item @var{file}.f90
+@itemx @var{file}.f95
+@itemx @var{file}.f03
+@itemx @var{file}.f08
+Free form Fortran source code which should not be preprocessed.
-@xref{Overall Options,,Options Controlling the Kind of Output, g77,
-Using and Porting GNU Fortran}, for more details of the handling of
-Fortran input files.
+@item @var{file}.F90
+@itemx @var{file}.F95
+@itemx @var{file}.F03
+@itemx @var{file}.F08
+Free form Fortran source code which must be preprocessed (with the
+traditional preprocessor).
@c FIXME: Descriptions of Java file types.
@c @var{file}.java
generic, or subprogram renaming declaration). Such files are also
called @dfn{specs}.
-@itemx @var{file}.adb
+@item @var{file}.adb
Ada source code file containing a library unit body (a subprogram or
package body). Such files are also called @dfn{bodies}.
@c Pascal:
@c @var{file}.p
@c @var{file}.pas
+@c Ratfor:
+@c @var{file}.r
@item @var{file}.s
Assembler code.
@item @var{file}.S
+@itemx @var{file}.sx
Assembler code which must be preprocessed.
@item @var{other}
(rather than letting the compiler choose a default based on the file
name suffix). This option applies to all following input files until
the next @option{-x} option. Possible values for @var{language} are:
-@example
-c c-header cpp-output
-c++ c++-cpp-output
-objective-c objc-cpp-output
+@smallexample
+c c-header c-cpp-output
+c++ c++-header c++-cpp-output
+objective-c objective-c-header objective-c-cpp-output
+objective-c++ objective-c++-header objective-c++-cpp-output
assembler assembler-with-cpp
ada
-f77 f77-cpp-input ratfor
+f77 f77-cpp-input f95 f95-cpp-input
java
-@end example
+@end smallexample
@item -x none
Turn off any specification of a language, so that subsequent files are
phase of the compiler returns a non-success return code. If you specify
@option{-pass-exit-codes}, the @command{gcc} program will instead return with
numerically highest error produced by any phase that returned an error
-indication.
+indication. The C, C++, and Fortran frontends return 4, if an internal
+compiler error is encountered.
@end table
If you only want some of the stages of compilation, you can use
sort of output is being produced, whether it be an executable file,
an object file, an assembler file or preprocessed C code.
-Since only one output file can be specified, it does not make sense to
-use @option{-o} when compiling more than one input file, unless you are
-producing an executable file as output.
-
-If @option{-o} is not specified, the default is to put an executable file
-in @file{a.out}, the object file for @file{@var{source}.@var{suffix}} in
-@file{@var{source}.o}, its assembler file in @file{@var{source}.s}, and
-all preprocessed C source on standard output.
+If @option{-o} is not specified, the default is to put an executable
+file in @file{a.out}, the object file for
+@file{@var{source}.@var{suffix}} in @file{@var{source}.o}, its
+assembler file in @file{@var{source}.s}, a precompiled header file in
+@file{@var{source}.@var{suffix}.gch}, and all preprocessed C source on
+standard output.
@item -v
@opindex v
the assembler is unable to read from a pipe; but the GNU assembler has
no trouble.
+@item -combine
+@opindex combine
+If you are compiling multiple source files, this option tells the driver
+to pass all the source files to the compiler at once (for those
+languages for which the compiler can handle this). This will allow
+intermodule analysis (IMA) to be performed by the compiler. Currently the only
+language for which this is supported is C@. If you pass source files for
+multiple languages to the driver, using this option, the driver will invoke
+the compiler(s) that support IMA once each, passing each compiler all the
+source files appropriate for it. For those languages that do not support
+IMA this option will be ignored, and the compiler will be invoked once for
+each source file in that language. If you use this option in conjunction
+with @option{-save-temps}, the compiler will generate multiple
+pre-processed files
+(one for each source file), but only one (combined) @file{.o} or
+@file{.s} file.
+
@item --help
@opindex help
Print (on the standard output) a description of the command line options
understood by @command{gcc}. If the @option{-v} option is also specified
then @option{--help} will also be passed on to the various processes
invoked by @command{gcc}, so that they can display the command line options
-they accept. If the @option{-W} option is also specified then command
-line options which have no documentation associated with them will also
-be displayed.
+they accept. If the @option{-Wextra} option has also been specified
+(prior to the @option{--help} option), then command line options which
+have no documentation associated with them will also be displayed.
@item --target-help
@opindex target-help
-Print (on the standard output) a description of target specific command
-line options for each tool.
+Print (on the standard output) a description of target-specific command
+line options for each tool. For some targets extra target-specific
+information may also be printed.
+
+@item --help=@{@var{class}@r{|[}^@r{]}@var{qualifier}@}@r{[},@dots{}@r{]}
+Print (on the standard output) a description of the command line
+options understood by the compiler that fit into all specified classes
+and qualifiers. These are the supported classes:
+
+@table @asis
+@item @samp{optimizers}
+This will display all of the optimization options supported by the
+compiler.
-@item --version
-@opindex version
-Display the version number and copyrights of the invoked GCC.
+@item @samp{warnings}
+This will display all of the options controlling warning messages
+produced by the compiler.
+
+@item @samp{target}
+This will display target-specific options. Unlike the
+@option{--target-help} option however, target-specific options of the
+linker and assembler will not be displayed. This is because those
+tools do not currently support the extended @option{--help=} syntax.
+
+@item @samp{params}
+This will display the values recognized by the @option{--param}
+option.
+
+@item @var{language}
+This will display the options supported for @var{language}, where
+@var{language} is the name of one of the languages supported in this
+version of GCC.
+
+@item @samp{common}
+This will display the options that are common to all languages.
@end table
-@node Invoking G++
-@section Compiling C++ Programs
+These are the supported qualifiers:
-@cindex suffixes for C++ source
-@cindex C++ source file suffixes
-C++ source files conventionally use one of the suffixes @samp{.C},
-@samp{.cc}, @samp{.cpp}, @samp{.c++}, @samp{.cp}, or @samp{.cxx};
-preprocessed C++ files use the suffix @samp{.ii}. GCC recognizes
-files with these names and compiles them as C++ programs even if you
-call the compiler the same way as for compiling C programs (usually with
-the name @command{gcc}).
+@table @asis
+@item @samp{undocumented}
+Display only those options which are undocumented.
-@findex g++
-@findex c++
-However, C++ programs often require class libraries as well as a
-compiler that understands the C++ language---and under some
-circumstances, you might want to compile programs from standard input,
-or otherwise without a suffix that flags them as C++ programs.
-@command{g++} is a program that calls GCC with the default language
-set to C++, and automatically specifies linking against the C++
-library. On many systems, @command{g++} is also
-installed with the name @command{c++}.
+@item @samp{joined}
+Display options which take an argument that appears after an equal
+sign in the same continuous piece of text, such as:
+@samp{--help=target}.
-@cindex invoking @command{g++}
-When you compile C++ programs, you may specify many of the same
-command-line options that you use for compiling programs in any
-language; or command-line options meaningful for C and related
-languages; or options that are meaningful only for C++ programs.
-@xref{C Dialect Options,,Options Controlling C Dialect}, for
-explanations of options for languages related to C@.
-@xref{C++ Dialect Options,,Options Controlling C++ Dialect}, for
-explanations of options that are meaningful only for C++ programs.
+@item @samp{separate}
+Display options which take an argument that appears as a separate word
+following the original option, such as: @samp{-o output-file}.
+@end table
-@node C Dialect Options
-@section Options Controlling C Dialect
-@cindex dialect options
-@cindex language dialect options
-@cindex options, dialect
+Thus for example to display all the undocumented target-specific
+switches supported by the compiler the following can be used:
-The following options control the dialect of C (or languages derived
-from C, such as C++ and Objective-C) that the compiler accepts:
+@smallexample
+--help=target,undocumented
+@end smallexample
-@table @gcctabopt
-@cindex ANSI support
-@cindex ISO support
-@item -ansi
-@opindex ansi
-In C mode, support all ISO C89 programs. In C++ mode,
-remove GNU extensions that conflict with ISO C++.
+The sense of a qualifier can be inverted by prefixing it with the
+@samp{^} character, so for example to display all binary warning
+options (i.e., ones that are either on or off and that do not take an
+argument), which have a description the following can be used:
-This turns off certain features of GCC that are incompatible with ISO
-C89 (when compiling C code), or of standard C++ (when compiling C++ code),
+@smallexample
+--help=warnings,^joined,^undocumented
+@end smallexample
+
+The argument to @option{--help=} should not consist solely of inverted
+qualifiers.
+
+Combining several classes is possible, although this usually
+restricts the output by so much that there is nothing to display. One
+case where it does work however is when one of the classes is
+@var{target}. So for example to display all the target-specific
+optimization options the following can be used:
+
+@smallexample
+--help=target,optimizers
+@end smallexample
+
+The @option{--help=} option can be repeated on the command line. Each
+successive use will display its requested class of options, skipping
+those that have already been displayed.
+
+If the @option{-Q} option appears on the command line before the
+@option{--help=} option, then the descriptive text displayed by
+@option{--help=} is changed. Instead of describing the displayed
+options, an indication is given as to whether the option is enabled,
+disabled or set to a specific value (assuming that the compiler
+knows this at the point where the @option{--help=} option is used).
+
+Here is a truncated example from the ARM port of @command{gcc}:
+
+@smallexample
+ % gcc -Q -mabi=2 --help=target -c
+ The following options are target specific:
+ -mabi= 2
+ -mabort-on-noreturn [disabled]
+ -mapcs [disabled]
+@end smallexample
+
+The output is sensitive to the effects of previous command line
+options, so for example it is possible to find out which optimizations
+are enabled at @option{-O2} by using:
+
+@smallexample
+-Q -O2 --help=optimizers
+@end smallexample
+
+Alternatively you can discover which binary optimizations are enabled
+by @option{-O3} by using:
+
+@smallexample
+gcc -c -Q -O3 --help=optimizers > /tmp/O3-opts
+gcc -c -Q -O2 --help=optimizers > /tmp/O2-opts
+diff /tmp/O2-opts /tmp/O3-opts | grep enabled
+@end smallexample
+
+@item --version
+@opindex version
+Display the version number and copyrights of the invoked GCC@.
+
+@item -wrapper
+@opindex wrapper
+Invoke all subcommands under a wrapper program. It takes a single
+comma separated list as an argument, which will be used to invoke
+the wrapper:
+
+@smallexample
+gcc -c t.c -wrapper gdb,--args
+@end smallexample
+
+This will invoke all subprograms of gcc under "gdb --args",
+thus cc1 invocation will be "gdb --args cc1 ...".
+
+@include @value{srcdir}/../libiberty/at-file.texi
+@end table
+
+@node Invoking G++
+@section Compiling C++ Programs
+
+@cindex suffixes for C++ source
+@cindex C++ source file suffixes
+C++ source files conventionally use one of the suffixes @samp{.C},
+@samp{.cc}, @samp{.cpp}, @samp{.CPP}, @samp{.c++}, @samp{.cp}, or
+@samp{.cxx}; C++ header files often use @samp{.hh}, @samp{.hpp},
+@samp{.H}, or (for shared template code) @samp{.tcc}; and
+preprocessed C++ files use the suffix @samp{.ii}. GCC recognizes
+files with these names and compiles them as C++ programs even if you
+call the compiler the same way as for compiling C programs (usually
+with the name @command{gcc}).
+
+@findex g++
+@findex c++
+However, the use of @command{gcc} does not add the C++ library.
+@command{g++} is a program that calls GCC and treats @samp{.c},
+@samp{.h} and @samp{.i} files as C++ source files instead of C source
+files unless @option{-x} is used, and automatically specifies linking
+against the C++ library. This program is also useful when
+precompiling a C header file with a @samp{.h} extension for use in C++
+compilations. On many systems, @command{g++} is also installed with
+the name @command{c++}.
+
+@cindex invoking @command{g++}
+When you compile C++ programs, you may specify many of the same
+command-line options that you use for compiling programs in any
+language; or command-line options meaningful for C and related
+languages; or options that are meaningful only for C++ programs.
+@xref{C Dialect Options,,Options Controlling C Dialect}, for
+explanations of options for languages related to C@.
+@xref{C++ Dialect Options,,Options Controlling C++ Dialect}, for
+explanations of options that are meaningful only for C++ programs.
+
+@node C Dialect Options
+@section Options Controlling C Dialect
+@cindex dialect options
+@cindex language dialect options
+@cindex options, dialect
+
+The following options control the dialect of C (or languages derived
+from C, such as C++, Objective-C and Objective-C++) that the compiler
+accepts:
+
+@table @gcctabopt
+@cindex ANSI support
+@cindex ISO support
+@item -ansi
+@opindex ansi
+In C mode, this is equivalent to @samp{-std=c89}. In C++ mode, it is
+equivalent to @samp{-std=c++98}.
+
+This turns off certain features of GCC that are incompatible with ISO
+C90 (when compiling C code), or of standard C++ (when compiling C++ code),
such as the @code{asm} and @code{typeof} keywords, and
predefined macros such as @code{unix} and @code{vax} that identify the
type of system you are using. It also enables the undesirable and
ISO standard doesn't call for; this is to avoid interfering with any
programs that might use these names for other things.
-Functions which would normally be built in but do not have semantics
+Functions that would normally be built in but do not have semantics
defined by ISO C (such as @code{alloca} and @code{ffs}) are not built-in
-functions with @option{-ansi} is used. @xref{Other Builtins,,Other
+functions when @option{-ansi} is used. @xref{Other Builtins,,Other
built-in functions provided by GCC}, for details of the functions
affected.
@item -std=
@opindex std
-Determine the language standard. This option is currently only
-supported when compiling C@. A value for this option must be provided;
-possible values are
+Determine the language standard. @xref{Standards,,Language Standards
+Supported by GCC}, for details of these standard versions. This option
+is currently only supported when compiling C or C++.
+
+The compiler can accept several base standards, such as @samp{c89} or
+@samp{c++98}, and GNU dialects of those standards, such as
+@samp{gnu89} or @samp{gnu++98}. By specifying a base standard, the
+compiler will accept all programs following that standard and those
+using GNU extensions that do not contradict it. For example,
+@samp{-std=c89} turns off certain features of GCC that are
+incompatible with ISO C90, such as the @code{asm} and @code{typeof}
+keywords, but not other GNU extensions that do not have a meaning in
+ISO C90, such as omitting the middle term of a @code{?:}
+expression. On the other hand, by specifying a GNU dialect of a
+standard, all features the compiler support are enabled, even when
+those features change the meaning of the base standard and some
+strict-conforming programs may be rejected. The particular standard
+is used by @option{-pedantic} to identify which features are GNU
+extensions given that version of the standard. For example
+@samp{-std=gnu89 -pedantic} would warn about C++ style @samp{//}
+comments, while @samp{-std=gnu99 -pedantic} would not.
+
+A value for this option must be provided; possible values are
@table @samp
@item c89
@itemx iso9899:1990
-ISO C89 (same as @option{-ansi}).
+Support all ISO C90 programs (certain GNU extensions that conflict
+with ISO C90 are disabled). Same as @option{-ansi} for C code.
@item iso9899:199409
-ISO C89 as modified in amendment 1.
+ISO C90 as modified in amendment 1.
@item c99
@itemx c9x
@itemx iso9899:1999
@itemx iso9899:199x
ISO C99. Note that this standard is not yet fully supported; see
-@w{@uref{http://gcc.gnu.org/gcc-3.1/c99status.html}} for more information. The
+@w{@uref{http://gcc.gnu.org/gcc-4.4/c99status.html}} for more information. The
names @samp{c9x} and @samp{iso9899:199x} are deprecated.
@item gnu89
-Default, ISO C89 plus GNU extensions (including some C99 features).
+GNU dialect of ISO C90 (including some C99 features). This
+is the default for C code.
@item gnu99
-@item gnu9x
-ISO C99 plus GNU extensions. When ISO C99 is fully implemented in GCC,
+@itemx gnu9x
+GNU dialect of ISO C99. When ISO C99 is fully implemented in GCC,
this will become the default. The name @samp{gnu9x} is deprecated.
-@end table
+@item c++98
+The 1998 ISO C++ standard plus amendments. Same as @option{-ansi} for
+C++ code.
-Even when this option is not specified, you can still use some of the
-features of newer standards in so far as they do not conflict with
-previous C standards. For example, you may use @code{__restrict__} even
-when @option{-std=c99} is not specified.
+@item gnu++98
+GNU dialect of @option{-std=c++98}. This is the default for
+C++ code.
-The @option{-std} options specifying some version of ISO C have the same
-effects as @option{-ansi}, except that features that were not in ISO C89
-but are in the specified version (for example, @samp{//} comments and
-the @code{inline} keyword in ISO C99) are not disabled.
+@item c++0x
+The working draft of the upcoming ISO C++0x standard. This option
+enables experimental features that are likely to be included in
+C++0x. The working draft is constantly changing, and any feature that is
+enabled by this flag may be removed from future versions of GCC if it is
+not part of the C++0x standard.
-@xref{Standards,,Language Standards Supported by GCC}, for details of
-these standard versions.
+@item gnu++0x
+GNU dialect of @option{-std=c++0x}. This option enables
+experimental features that may be removed in future versions of GCC.
+@end table
+
+@item -fgnu89-inline
+@opindex fgnu89-inline
+The option @option{-fgnu89-inline} tells GCC to use the traditional
+GNU semantics for @code{inline} functions when in C99 mode.
+@xref{Inline,,An Inline Function is As Fast As a Macro}. This option
+is accepted and ignored by GCC versions 4.1.3 up to but not including
+4.3. In GCC versions 4.3 and later it changes the behavior of GCC in
+C99 mode. Using this option is roughly equivalent to adding the
+@code{gnu_inline} function attribute to all inline functions
+(@pxref{Function Attributes}).
+
+The option @option{-fno-gnu89-inline} explicitly tells GCC to use the
+C99 semantics for @code{inline} when in C99 or gnu99 mode (i.e., it
+specifies the default behavior). This option was first supported in
+GCC 4.3. This option is not supported in C89 or gnu89 mode.
+
+The preprocessor macros @code{__GNUC_GNU_INLINE__} and
+@code{__GNUC_STDC_INLINE__} may be used to check which semantics are
+in effect for @code{inline} functions. @xref{Common Predefined
+Macros,,,cpp,The C Preprocessor}.
@item -aux-info @var{filename}
@opindex aux-info
@code{inline} is a standard keyword in ISO C99.
@item -fno-builtin
-@itemx -fno-builtin-@var{function} @r{(C and Objective-C only)}
+@itemx -fno-builtin-@var{function}
@opindex fno-builtin
@cindex built-in functions
Don't recognize built-in functions that do not begin with
may become inline copy loops. The resulting code is often both smaller
and faster, but since the function calls no longer appear as such, you
cannot set a breakpoint on those calls, nor can you change the behavior
-of the functions by linking with a different library.
-
-In C++, @option{-fno-builtin} is always in effect. The @option{-fbuiltin}
-option has no effect. Therefore, in C++, the only way to get the
-optimization benefits of built-in functions is to call the function
-using the @samp{__builtin_} prefix. The GNU C++ Standard Library uses
-built-in functions to implement many functions (like
-@code{std::strchr}), so that you automatically get efficient code.
-
-With the @option{-fno-builtin-@var{function}} option, not available
-when compiling C++, only the built-in function @var{function} is
+of the functions by linking with a different library. In addition,
+when a function is recognized as a built-in function, GCC may use
+information about that function to warn about problems with calls to
+that function, or to generate more efficient code, even if the
+resulting code still contains calls to that function. For example,
+warnings are given with @option{-Wformat} for bad calls to
+@code{printf}, when @code{printf} is built in, and @code{strlen} is
+known not to modify global memory.
+
+With the @option{-fno-builtin-@var{function}} option
+only the built-in function @var{function} is
disabled. @var{function} must not begin with @samp{__builtin_}. If a
-function is named this is not built-in in this version of GCC, this
+function is named that is not built-in in this version of GCC, this
option is ignored. There is no corresponding
@option{-fbuiltin-@var{function}} option; if you wish to enable
built-in functions selectively when using @option{-fno-builtin} or
@xref{Standards,,Language Standards Supported by GCC}, for details of
freestanding and hosted environments.
+@item -fopenmp
+@opindex fopenmp
+@cindex openmp parallel
+Enable handling of OpenMP directives @code{#pragma omp} in C/C++ and
+@code{!$omp} in Fortran. When @option{-fopenmp} is specified, the
+compiler generates parallel code according to the OpenMP Application
+Program Interface v2.5 @w{@uref{http://www.openmp.org/}}. This option
+implies @option{-pthread}, and thus is only supported on targets that
+have support for @option{-pthread}.
+
+@item -fms-extensions
+@opindex fms-extensions
+Accept some non-standard constructs used in Microsoft header files.
+
+Some cases of unnamed fields in structures and unions are only
+accepted with this option. @xref{Unnamed Fields,,Unnamed struct/union
+fields within structs/unions}, for details.
+
@item -trigraphs
@opindex trigraphs
Support ISO C trigraphs. The @option{-ansi} option (and @option{-std}
@item -no-integrated-cpp
@opindex no-integrated-cpp
-Invoke the external cpp during compilation. The default is to use the
-integrated cpp (internal cpp). This option also allows a
-user-supplied cpp via the @option{-B} option. This flag is applicable
-in both C and C++ modes.
+Performs a compilation in two passes: preprocessing and compiling. This
+option allows a user supplied "cc1", "cc1plus", or "cc1obj" via the
+@option{-B} option. The user supplied compilation step can then add in
+an additional preprocessing step after normal preprocessing but before
+compiling. The default is to use the integrated cpp (internal cpp)
-We do not guarantee to retain this option in future, and we may change
-its semantics.
+The semantics of this option will change if "cc1", "cc1plus", and
+"cc1obj" are merged.
@cindex traditional C language
@cindex C language, traditional
@item -traditional
-@opindex traditional
-Attempt to support some aspects of traditional C compilers.
-Specifically:
-
-@itemize @bullet
-@item
-All @code{extern} declarations take effect globally even if they
-are written inside of a function definition. This includes implicit
-declarations of functions.
-
-@item
-The newer keywords @code{typeof}, @code{inline}, @code{signed}, @code{const}
-and @code{volatile} are not recognized. (You can still use the
-alternative keywords such as @code{__typeof__}, @code{__inline__}, and
-so on.)
-
-@item
-Comparisons between pointers and integers are always allowed.
-
-@item
-Integer types @code{unsigned short} and @code{unsigned char} promote
-to @code{unsigned int}.
-
-@item
-Out-of-range floating point literals are not an error.
-
-@item
-Certain constructs which ISO regards as a single invalid preprocessing
-number, such as @samp{0xe-0xd}, are treated as expressions instead.
-
-@item
-String ``constants'' are not necessarily constant; they are stored in
-writable space, and identical looking constants are allocated
-separately. (This is the same as the effect of
-@option{-fwritable-strings}.)
-
-@cindex @code{longjmp} and automatic variables
-@item
-All automatic variables not declared @code{register} are preserved by
-@code{longjmp}. Ordinarily, GNU C follows ISO C: automatic variables
-not declared @code{volatile} may be clobbered.
-
-@item
-@cindex @samp{\x}
-@cindex @samp{\a}
-@cindex escape sequences, traditional
-The character escape sequences @samp{\x} and @samp{\a} evaluate as the
-literal characters @samp{x} and @samp{a} respectively. Without
-@w{@option{-traditional}}, @samp{\x} is a prefix for the hexadecimal
-representation of a character, and @samp{\a} produces a bell.
-@end itemize
-
-This option is deprecated and may be removed.
-
-You may wish to use @option{-fno-builtin} as well as @option{-traditional}
-if your program uses names that are normally GNU C built-in functions for
-other purposes of its own.
-
-You cannot use @option{-traditional} if you include any header files that
-rely on ISO C features. Some vendors are starting to ship systems with
-ISO C header files and you cannot use @option{-traditional} on such
-systems to compile files that include any system headers.
-
-The @option{-traditional} option also enables @option{-traditional-cpp}.
-
-@item -traditional-cpp
+@itemx -traditional-cpp
@opindex traditional-cpp
-Attempt to support some aspects of traditional C preprocessors.
-See the GNU CPP manual for details.
+@opindex traditional
+Formerly, these options caused GCC to attempt to emulate a pre-standard
+C compiler. They are now only supported with the @option{-E} switch.
+The preprocessor continues to support a pre-standard mode. See the GNU
+CPP manual for details.
@item -fcond-mismatch
@opindex fcond-mismatch
third arguments. The value of such an expression is void. This option
is not supported for C++.
+@item -flax-vector-conversions
+@opindex flax-vector-conversions
+Allow implicit conversions between vectors with differing numbers of
+elements and/or incompatible element types. This option should not be
+used for new code.
+
@item -funsigned-char
@opindex funsigned-char
Let the type @code{char} be unsigned, like @code{unsigned char}.
declaration does not use either @code{signed} or @code{unsigned}. By
default, such a bit-field is signed, because this is consistent: the
basic integer types such as @code{int} are signed types.
-
-However, when @option{-traditional} is used, bit-fields are all unsigned
-no matter what.
-
-@item -fwritable-strings
-@opindex fwritable-strings
-Store string constants in the writable data segment and don't uniquize
-them. This is for compatibility with old programs which assume they can
-write into string constants. The option @option{-traditional} also has
-this effect.
-
-Writing into string constants is a very bad idea; ``constants'' should
-be constant.
-
-@item -fallow-single-precision
-@opindex fallow-single-precision
-Do not promote single precision math operations to double precision,
-even when compiling with @option{-traditional}.
-
-Traditional K&R C promotes all floating point operations to double
-precision, regardless of the sizes of the operands. On the
-architecture for which you are compiling, single precision may be faster
-than double precision. If you must use @option{-traditional}, but want
-to use single precision operations when the operands are single
-precision, use this option. This option has no effect when compiling
-with ISO or GNU C conventions (the default).
@end table
@node C++ Dialect Options
regardless of what language your program is in. For example, you
might compile a file @code{firstClass.C} like this:
-@example
+@smallexample
g++ -g -frepo -O -c firstClass.C
-@end example
+@end smallexample
@noindent
In this example, only @option{-frepo} is an option meant
Here is a list of options that are @emph{only} for compiling C++ programs:
@table @gcctabopt
+
+@item -fabi-version=@var{n}
+@opindex fabi-version
+Use version @var{n} of the C++ ABI@. Version 2 is the version of the
+C++ ABI that first appeared in G++ 3.4. Version 1 is the version of
+the C++ ABI that first appeared in G++ 3.2. Version 0 will always be
+the version that conforms most closely to the C++ ABI specification.
+Therefore, the ABI obtained using version 0 will change as ABI bugs
+are fixed.
+
+The default is version 2.
+
@item -fno-access-control
@opindex fno-access-control
Turn off all access checking. This switch is mainly useful for working
@item -fcheck-new
@opindex fcheck-new
Check that the pointer returned by @code{operator new} is non-null
-before attempting to modify the storage allocated. The current Working
-Paper requires that @code{operator new} never return a null pointer, so
-this check is normally unnecessary.
-
-An alternative to using this option is to specify that your
-@code{operator new} does not throw any exceptions; if you declare it
-@samp{throw()}, G++ will check the return value. See also @samp{new
-(nothrow)}.
+before attempting to modify the storage allocated. This check is
+normally unnecessary because the C++ standard specifies that
+@code{operator new} will only return @code{0} if it is declared
+@samp{throw()}, in which case the compiler will always check the
+return value even without this option. In all other cases, when
+@code{operator new} has a non-empty exception specification, memory
+exhaustion is signalled by throwing @code{std::bad_alloc}. See also
+@samp{new (nothrow)}.
@item -fconserve-space
@opindex fconserve-space
This option is no longer useful on most targets, now that support has
been added for putting variables into BSS without making them common.
-@item -fno-const-strings
-@opindex fno-const-strings
-Give string constants type @code{char *} instead of type @code{const
-char *}. By default, G++ uses type @code{const char *} as required by
-the standard. Even if you use @option{-fno-const-strings}, you cannot
-actually modify the value of a string constant, unless you also use
-@option{-fwritable-strings}.
-
-This option might be removed in a future release of G++. For maximum
-portability, you should structure your code so that it works with
-string constants that have type @code{const char *}.
-
-@item -fdollars-in-identifiers
-@opindex fdollars-in-identifiers
-Accept @samp{$} in identifiers. You can also explicitly prohibit use of
-@samp{$} with the option @option{-fno-dollars-in-identifiers}. (GNU C allows
-@samp{$} by default on most target systems, but there are a few exceptions.)
-Traditional C allowed the character @samp{$} to form part of
-identifiers. However, ISO C and C++ forbid @samp{$} in identifiers.
+@item -fno-deduce-init-list
+@opindex fno-deduce-init-list
+Disable deduction of a template type parameter as
+std::initializer_list from a brace-enclosed initializer list, i.e.
+
+@smallexample
+template <class T> auto forward(T t) -> decltype (realfn (t))
+@{
+ return realfn (t);
+@}
+
+void f()
+@{
+ forward(@{1,2@}); // call forward<std::initializer_list<int>>
+@}
+@end smallexample
+
+This option is present because this deduction is an extension to the
+current specification in the C++0x working draft, and there was
+some concern about potential overload resolution problems.
+
+@item -ffriend-injection
+@opindex ffriend-injection
+Inject friend functions into the enclosing namespace, so that they are
+visible outside the scope of the class in which they are declared.
+Friend functions were documented to work this way in the old Annotated
+C++ Reference Manual, and versions of G++ before 4.1 always worked
+that way. However, in ISO C++ a friend function which is not declared
+in an enclosing scope can only be found using argument dependent
+lookup. This option causes friends to be injected as they were in
+earlier releases.
+
+This option is for compatibility, and may be removed in a future
+release of G++.
@item -fno-elide-constructors
@opindex fno-elide-constructors
@item -fno-enforce-eh-specs
@opindex fno-enforce-eh-specs
-Don't check for violation of exception specifications at runtime. This
-option violates the C++ standard, but may be useful for reducing code
-size in production builds, much like defining @samp{NDEBUG}. The compiler
-will still optimize based on the exception specifications.
-
-@item -fexternal-templates
-@opindex fexternal-templates
-
-Cause @samp{#pragma interface} and @samp{implementation} to apply to
-template instantiation; template instances are emitted or not according
-to the location of the template definition. @xref{Template
-Instantiation}, for more information.
-
-This option is deprecated.
-
-@item -falt-external-templates
-@opindex falt-external-templates
-Similar to @option{-fexternal-templates}, but template instances are
-emitted or not according to the place where they are first instantiated.
-@xref{Template Instantiation}, for more information.
-
-This option is deprecated.
+Don't generate code to check for violation of exception specifications
+at runtime. This option violates the C++ standard, but may be useful
+for reducing code size in production builds, much like defining
+@samp{NDEBUG}. This does not give user code permission to throw
+exceptions in violation of the exception specifications; the compiler
+will still optimize based on the specifications, so throwing an
+unexpected exception will result in undefined behavior.
@item -ffor-scope
@itemx -fno-for-scope
@item -fpermissive
@opindex fpermissive
-Downgrade messages about nonconformant code from errors to warnings. By
-default, G++ effectively sets @option{-pedantic-errors} without
-@option{-pedantic}; this option reverses that. This behavior and this
-option are superseded by @option{-pedantic}, which works as it does for GNU C@.
+Downgrade some diagnostics about nonconformant code from errors to
+warnings. Thus, using @option{-fpermissive} will allow some
+nonconforming code to compile.
@item -frepo
@opindex frepo
(@samp{dynamic_cast} and @samp{typeid}). If you don't use those parts
of the language, you can save some space by using this flag. Note that
exception handling uses the same information, but it will generate it as
-needed.
+needed. The @samp{dynamic_cast} operator can still be used for casts that
+do not require runtime type information, i.e.@: casts to @code{void *} or to
+unambiguous base classes.
@item -fstats
@opindex fstats
endless recursions during template class instantiation. ANSI/ISO C++
conforming programs must not rely on a maximum depth greater than 17.
+@item -fno-threadsafe-statics
+@opindex fno-threadsafe-statics
+Do not emit the extra code to use the routines specified in the C++
+ABI for thread-safe initialization of local statics. You can use this
+option to reduce code size slightly in code that doesn't need to be
+thread-safe.
+
@item -fuse-cxa-atexit
@opindex fuse-cxa-atexit
Register destructors for objects with static storage duration with the
destructors, but will only work if your C library supports
@code{__cxa_atexit}.
-@item -fvtable-gc
-@opindex fvtable-gc
-Emit special relocations for vtables and virtual function references
-so that the linker can identify unused virtual functions and zero out
-vtable slots that refer to them. This is most useful with
-@option{-ffunction-sections} and @option{-Wl,--gc-sections}, in order to
-also discard the functions themselves.
+@item -fno-use-cxa-get-exception-ptr
+@opindex fno-use-cxa-get-exception-ptr
+Don't use the @code{__cxa_get_exception_ptr} runtime routine. This
+will cause @code{std::uncaught_exception} to be incorrect, but is necessary
+if the runtime routine is not available.
+
+@item -fvisibility-inlines-hidden
+@opindex fvisibility-inlines-hidden
+This switch declares that the user does not attempt to compare
+pointers to inline methods where the addresses of the two functions
+were taken in different shared objects.
+
+The effect of this is that GCC may, effectively, mark inline methods with
+@code{__attribute__ ((visibility ("hidden")))} so that they do not
+appear in the export table of a DSO and do not require a PLT indirection
+when used within the DSO@. Enabling this option can have a dramatic effect
+on load and link times of a DSO as it massively reduces the size of the
+dynamic export table when the library makes heavy use of templates.
+
+The behavior of this switch is not quite the same as marking the
+methods as hidden directly, because it does not affect static variables
+local to the function or cause the compiler to deduce that
+the function is defined in only one shared object.
+
+You may mark a method as having a visibility explicitly to negate the
+effect of the switch for that method. For example, if you do want to
+compare pointers to a particular inline method, you might mark it as
+having default visibility. Marking the enclosing class with explicit
+visibility will have no effect.
+
+Explicitly instantiated inline methods are unaffected by this option
+as their linkage might otherwise cross a shared library boundary.
+@xref{Template Instantiation}.
+
+@item -fvisibility-ms-compat
+@opindex fvisibility-ms-compat
+This flag attempts to use visibility settings to make GCC's C++
+linkage model compatible with that of Microsoft Visual Studio.
+
+The flag makes these changes to GCC's linkage model:
+
+@enumerate
+@item
+It sets the default visibility to @code{hidden}, like
+@option{-fvisibility=hidden}.
+
+@item
+Types, but not their members, are not hidden by default.
+
+@item
+The One Definition Rule is relaxed for types without explicit
+visibility specifications which are defined in more than one different
+shared object: those declarations are permitted if they would have
+been permitted when this option was not used.
+@end enumerate
+
+In new code it is better to use @option{-fvisibility=hidden} and
+export those classes which are intended to be externally visible.
+Unfortunately it is possible for code to rely, perhaps accidentally,
+on the Visual Studio behavior.
-This optimization requires GNU as and GNU ld. Not all systems support
-this option. @option{-Wl,--gc-sections} is ignored without @option{-static}.
+Among the consequences of these changes are that static data members
+of the same type with the same name but defined in different shared
+objects will be different, so changing one will not change the other;
+and that pointers to function members defined in different shared
+objects may not compare equal. When this flag is given, it is a
+violation of the ODR to define types with the same name differently.
@item -fno-weak
@opindex fno-weak
functions will have linkage like inline functions; they just won't be
inlined by default.
-@item -Wabi @r{(C++ only)}
+@item -Wabi @r{(C, Objective-C, C++ and Objective-C++ only)}
@opindex Wabi
+@opindex Wno-abi
Warn when G++ generates code that is probably not compatible with the
-vendor-neutral C++ ABI. Although an effort has been made to warn about
-all such cases, there are probably some cases that are not warned about,
+vendor-neutral C++ ABI@. Although an effort has been made to warn about
+all such cases, there are probably some cases that are not warned about,
even though G++ is generating incompatible code. There may also be
cases where warnings are emitted even though the code that is generated
will be compatible.
concerned about the fact that code generated by G++ may not be binary
compatible with code generated by other compilers.
-The known incompatibilites at this point include:
+The known incompatibilities at this point include:
@itemize @bullet
@noindent
In this case, G++ will place @code{B::f2} into the same byte
-as@code{A::f1}; other compilers will not. You can avoid this problem
+as@code{A::f1}; other compilers will not. You can avoid this problem
by explicitly padding @code{A} so that its size is a multiple of the
byte size on your platform; that will cause G++ and other compilers to
layout @code{B} identically.
alignment (ignoring virtual base classes); that will cause G++ and other
compilers to layout @code{C} identically.
+@item
+Incorrect handling of bit-fields with declared widths greater than that
+of their underlying types, when the bit-fields appear in a union. For
+example:
+
+@smallexample
+union U @{ int i : 4096; @};
+@end smallexample
+
+@noindent
+Assuming that an @code{int} does not have 4096 bits, G++ will make the
+union too small by the number of bits in an @code{int}.
+
+@item
+Empty classes can be placed at incorrect offsets. For example:
+
+@smallexample
+struct A @{@};
+
+struct B @{
+ A a;
+ virtual void f ();
+@};
+
+struct C : public B, public A @{@};
+@end smallexample
+
+@noindent
+G++ will place the @code{A} base class of @code{C} at a nonzero offset;
+it should be placed at offset zero. G++ mistakenly believes that the
+@code{A} data member of @code{B} is already at offset zero.
+
+@item
+Names of template functions whose types involve @code{typename} or
+template template parameters can be mangled incorrectly.
+
+@smallexample
+template <typename Q>
+void f(typename Q::X) @{@}
+
+template <template <typename> class Q>
+void f(typename Q<int>::X) @{@}
+@end smallexample
+
+@noindent
+Instantiations of these templates may be mangled incorrectly.
+
+@end itemize
+
+It also warns psABI related changes. The known psABI changes at this
+point include:
+
+@itemize @bullet
+
+@item
+For SYSV/x86-64, when passing union with long double, it is changed to
+pass in memory as specified in psABI. For example:
+
+@smallexample
+union U @{
+ long double ld;
+ int i;
+@};
+@end smallexample
+
+@noindent
+@code{union U} will always be passed in memory.
+
@end itemize
-@item -Wctor-dtor-privacy @r{(C++ only)}
+@item -Wctor-dtor-privacy @r{(C++ and Objective-C++ only)}
@opindex Wctor-dtor-privacy
-Warn when a class seems unusable, because all the constructors or
-destructors in a class are private and the class has no friends or
+@opindex Wno-ctor-dtor-privacy
+Warn when a class seems unusable because all the constructors or
+destructors in that class are private, and it has neither friends nor
public static member functions.
-@item -Wnon-virtual-dtor @r{(C++ only)}
+@item -Wnon-virtual-dtor @r{(C++ and Objective-C++ only)}
@opindex Wnon-virtual-dtor
-Warn when a class declares a non-virtual destructor that should probably
-be virtual, because it looks like the class will be used polymorphically.
+@opindex Wno-non-virtual-dtor
+Warn when a class has virtual functions and accessible non-virtual
+destructor, in which case it would be possible but unsafe to delete
+an instance of a derived class through a pointer to the base class.
+This warning is also enabled if -Weffc++ is specified.
-@item -Wreorder @r{(C++ only)}
+@item -Wreorder @r{(C++ and Objective-C++ only)}
@opindex Wreorder
+@opindex Wno-reorder
@cindex reordering, warning
@cindex warning for reordering of member initializers
Warn when the order of member initializers given in the code does not
@};
@end smallexample
-Here the compiler will warn that the member initializers for @samp{i}
-and @samp{j} will be rearranged to match the declaration order of the
-members.
+The compiler will rearrange the member initializers for @samp{i}
+and @samp{j} to match the declaration order of the members, emitting
+a warning to that effect. This warning is enabled by @option{-Wall}.
@end table
The following @option{-W@dots{}} options are not affected by @option{-Wall}.
@table @gcctabopt
-@item -Weffc++ @r{(C++ only)}
+@item -Weffc++ @r{(C++ and Objective-C++ only)}
@opindex Weffc++
+@opindex Wno-effc++
Warn about violations of the following style guidelines from Scott Meyers'
@cite{Effective C++} book:
@end itemize
-and about violations of the following style guidelines from Scott Meyers'
-@cite{More Effective C++} book:
+Also warn about violations of the following style guidelines from
+Scott Meyers' @cite{More Effective C++} book:
@itemize @bullet
@item
@end itemize
-If you use this option, you should be aware that the standard library
-headers do not obey all of these guidelines; you can use @samp{grep -v}
+When selecting this option, be aware that the standard library
+headers do not obey all of these guidelines; use @samp{grep -v}
to filter out those warnings.
-@item -Wno-deprecated @r{(C++ only)}
-@opindex Wno-deprecated
-Do not warn about usage of deprecated features. @xref{Deprecated Features}.
+@item -Wstrict-null-sentinel @r{(C++ and Objective-C++ only)}
+@opindex Wstrict-null-sentinel
+@opindex Wno-strict-null-sentinel
+Warn also about the use of an uncasted @code{NULL} as sentinel. When
+compiling only with GCC this is a valid sentinel, as @code{NULL} is defined
+to @code{__null}. Although it is a null pointer constant not a null pointer,
+it is guaranteed to be of the same size as a pointer. But this use is
+not portable across different compilers.
-@item -Wno-non-template-friend @r{(C++ only)}
+@item -Wno-non-template-friend @r{(C++ and Objective-C++ only)}
@opindex Wno-non-template-friend
+@opindex Wnon-template-friend
Disable warnings when non-templatized friend functions are declared
-within a template. With the advent of explicit template specification
+within a template. Since the advent of explicit template specification
support in G++, if the name of the friend is an unqualified-id (i.e.,
@samp{friend foo(int)}), the C++ language specification demands that the
friend declare or define an ordinary, nontemplate function. (Section
could be interpreted as a particular specialization of a templatized
function. Because this non-conforming behavior is no longer the default
behavior for G++, @option{-Wnon-template-friend} allows the compiler to
-check existing code for potential trouble spots, and is on by default.
+check existing code for potential trouble spots and is on by default.
This new compiler behavior can be turned off with
@option{-Wno-non-template-friend} which keeps the conformant compiler code
but disables the helpful warning.
-@item -Wold-style-cast @r{(C++ only)}
+@item -Wold-style-cast @r{(C++ and Objective-C++ only)}
@opindex Wold-style-cast
+@opindex Wno-old-style-cast
Warn if an old-style (C-style) cast to a non-void type is used within
-a C++ program. The new-style casts (@samp{static_cast},
-@samp{reinterpret_cast}, and @samp{const_cast}) are less vulnerable to
-unintended effects, and much easier to grep for.
+a C++ program. The new-style casts (@samp{dynamic_cast},
+@samp{static_cast}, @samp{reinterpret_cast}, and @samp{const_cast}) are
+less vulnerable to unintended effects and much easier to search for.
-@item -Woverloaded-virtual @r{(C++ only)}
+@item -Woverloaded-virtual @r{(C++ and Objective-C++ only)}
@opindex Woverloaded-virtual
+@opindex Wno-overloaded-virtual
@cindex overloaded virtual fn, warning
@cindex warning for overloaded virtual fn
Warn when a function declaration hides virtual functions from a
@end smallexample
the @code{A} class version of @code{f} is hidden in @code{B}, and code
-like this:
+like:
@smallexample
B* b;
will fail to compile.
-@item -Wno-pmf-conversions @r{(C++ only)}
+@item -Wno-pmf-conversions @r{(C++ and Objective-C++ only)}
@opindex Wno-pmf-conversions
+@opindex Wpmf-conversions
Disable the diagnostic for converting a bound pointer to member function
to a plain pointer.
-@item -Wsign-promo @r{(C++ only)}
+@item -Wsign-promo @r{(C++ and Objective-C++ only)}
@opindex Wsign-promo
+@opindex Wno-sign-promo
Warn when overload resolution chooses a promotion from unsigned or
-enumeral type to a signed type over a conversion to an unsigned type of
+enumerated type to a signed type, over a conversion to an unsigned type of
the same size. Previous versions of G++ would try to preserve
unsignedness, but the standard mandates the current behavior.
-@item -Wsynth @r{(C++ only)}
-@opindex Wsynth
-@cindex warning for synthesized methods
-@cindex synthesized methods, warning
-Warn when G++'s synthesis behavior does not match that of cfront. For
-instance:
-
@smallexample
struct A @{
operator int ();
(const A&);}, while cfront will use the user-defined @samp{operator =}.
@end table
-@node Objective-C Dialect Options
-@section Options Controlling Objective-C Dialect
+@node Objective-C and Objective-C++ Dialect Options
+@section Options Controlling Objective-C and Objective-C++ Dialects
+
+@cindex compiler options, Objective-C and Objective-C++
+@cindex Objective-C and Objective-C++ options, command line
+@cindex options, Objective-C and Objective-C++
+(NOTE: This manual does not describe the Objective-C and Objective-C++
+languages themselves. See @xref{Standards,,Language Standards
+Supported by GCC}, for references.)
-@cindex compiler options, Objective-C
-@cindex Objective-C options, command line
-@cindex options, Objective-C
This section describes the command-line options that are only meaningful
-for Objective-C programs; but you can also use most of the GNU compiler
-options regardless of what language your program is in. For example,
-you might compile a file @code{some_class.m} like this:
+for Objective-C and Objective-C++ programs, but you can also use most of
+the language-independent GNU compiler options.
+For example, you might compile a file @code{some_class.m} like this:
-@example
+@smallexample
gcc -g -fgnu-runtime -O -c some_class.m
-@end example
+@end smallexample
@noindent
-In this example, only @option{-fgnu-runtime} is an option meant only for
-Objective-C programs; you can use the other options with any language
-supported by GCC@.
+In this example, @option{-fgnu-runtime} is an option meant only for
+Objective-C and Objective-C++ programs; you can use the other options with
+any language supported by GCC@.
+
+Note that since Objective-C is an extension of the C language, Objective-C
+compilations may also use options specific to the C front-end (e.g.,
+@option{-Wtraditional}). Similarly, Objective-C++ compilations may use
+C++-specific options (e.g., @option{-Wabi}).
Here is a list of options that are @emph{only} for compiling Objective-C
-programs:
+and Objective-C++ programs:
@table @gcctabopt
@item -fconstant-string-class=@var{class-name}
@opindex fconstant-string-class
Use @var{class-name} as the name of the class to instantiate for each
literal string specified with the syntax @code{@@"@dots{}"}. The default
-class name is @code{NXConstantString}.
+class name is @code{NXConstantString} if the GNU runtime is being used, and
+@code{NSConstantString} if the NeXT runtime is being used (see below). The
+@option{-fconstant-cfstrings} option, if also present, will override the
+@option{-fconstant-string-class} setting and cause @code{@@"@dots{}"} literals
+to be laid out as constant CoreFoundation strings.
@item -fgnu-runtime
@opindex fgnu-runtime
@item -fnext-runtime
@opindex fnext-runtime
Generate output compatible with the NeXT runtime. This is the default
-for NeXT-based systems, including Darwin and Mac OS X@.
+for NeXT-based systems, including Darwin and Mac OS X@. The macro
+@code{__NEXT_RUNTIME__} is predefined if (and only if) this option is
+used.
+
+@item -fno-nil-receivers
+@opindex fno-nil-receivers
+Assume that all Objective-C message dispatches (e.g.,
+@code{[receiver message:arg]}) in this translation unit ensure that the receiver
+is not @code{nil}. This allows for more efficient entry points in the runtime
+to be used. Currently, this option is only available in conjunction with
+the NeXT runtime on Mac OS X 10.3 and later.
+
+@item -fobjc-call-cxx-cdtors
+@opindex fobjc-call-cxx-cdtors
+For each Objective-C class, check if any of its instance variables is a
+C++ object with a non-trivial default constructor. If so, synthesize a
+special @code{- (id) .cxx_construct} instance method that will run
+non-trivial default constructors on any such instance variables, in order,
+and then return @code{self}. Similarly, check if any instance variable
+is a C++ object with a non-trivial destructor, and if so, synthesize a
+special @code{- (void) .cxx_destruct} method that will run
+all such default destructors, in reverse order.
+
+The @code{- (id) .cxx_construct} and/or @code{- (void) .cxx_destruct} methods
+thusly generated will only operate on instance variables declared in the
+current Objective-C class, and not those inherited from superclasses. It
+is the responsibility of the Objective-C runtime to invoke all such methods
+in an object's inheritance hierarchy. The @code{- (id) .cxx_construct} methods
+will be invoked by the runtime immediately after a new object
+instance is allocated; the @code{- (void) .cxx_destruct} methods will
+be invoked immediately before the runtime deallocates an object instance.
+
+As of this writing, only the NeXT runtime on Mac OS X 10.4 and later has
+support for invoking the @code{- (id) .cxx_construct} and
+@code{- (void) .cxx_destruct} methods.
+
+@item -fobjc-direct-dispatch
+@opindex fobjc-direct-dispatch
+Allow fast jumps to the message dispatcher. On Darwin this is
+accomplished via the comm page.
+
+@item -fobjc-exceptions
+@opindex fobjc-exceptions
+Enable syntactic support for structured exception handling in Objective-C,
+similar to what is offered by C++ and Java. This option is
+unavailable in conjunction with the NeXT runtime on Mac OS X 10.2 and
+earlier.
+
+@smallexample
+ @@try @{
+ @dots{}
+ @@throw expr;
+ @dots{}
+ @}
+ @@catch (AnObjCClass *exc) @{
+ @dots{}
+ @@throw expr;
+ @dots{}
+ @@throw;
+ @dots{}
+ @}
+ @@catch (AnotherClass *exc) @{
+ @dots{}
+ @}
+ @@catch (id allOthers) @{
+ @dots{}
+ @}
+ @@finally @{
+ @dots{}
+ @@throw expr;
+ @dots{}
+ @}
+@end smallexample
+
+The @code{@@throw} statement may appear anywhere in an Objective-C or
+Objective-C++ program; when used inside of a @code{@@catch} block, the
+@code{@@throw} may appear without an argument (as shown above), in which case
+the object caught by the @code{@@catch} will be rethrown.
+
+Note that only (pointers to) Objective-C objects may be thrown and
+caught using this scheme. When an object is thrown, it will be caught
+by the nearest @code{@@catch} clause capable of handling objects of that type,
+analogously to how @code{catch} blocks work in C++ and Java. A
+@code{@@catch(id @dots{})} clause (as shown above) may also be provided to catch
+any and all Objective-C exceptions not caught by previous @code{@@catch}
+clauses (if any).
+
+The @code{@@finally} clause, if present, will be executed upon exit from the
+immediately preceding @code{@@try @dots{} @@catch} section. This will happen
+regardless of whether any exceptions are thrown, caught or rethrown
+inside the @code{@@try @dots{} @@catch} section, analogously to the behavior
+of the @code{finally} clause in Java.
+
+There are several caveats to using the new exception mechanism:
+
+@itemize @bullet
+@item
+Although currently designed to be binary compatible with @code{NS_HANDLER}-style
+idioms provided by the @code{NSException} class, the new
+exceptions can only be used on Mac OS X 10.3 (Panther) and later
+systems, due to additional functionality needed in the (NeXT) Objective-C
+runtime.
+
+@item
+As mentioned above, the new exceptions do not support handling
+types other than Objective-C objects. Furthermore, when used from
+Objective-C++, the Objective-C exception model does not interoperate with C++
+exceptions at this time. This means you cannot @code{@@throw} an exception
+from Objective-C and @code{catch} it in C++, or vice versa
+(i.e., @code{throw @dots{} @@catch}).
+@end itemize
+
+The @option{-fobjc-exceptions} switch also enables the use of synchronization
+blocks for thread-safe execution:
+
+@smallexample
+ @@synchronized (ObjCClass *guard) @{
+ @dots{}
+ @}
+@end smallexample
+
+Upon entering the @code{@@synchronized} block, a thread of execution shall
+first check whether a lock has been placed on the corresponding @code{guard}
+object by another thread. If it has, the current thread shall wait until
+the other thread relinquishes its lock. Once @code{guard} becomes available,
+the current thread will place its own lock on it, execute the code contained in
+the @code{@@synchronized} block, and finally relinquish the lock (thereby
+making @code{guard} available to other threads).
+
+Unlike Java, Objective-C does not allow for entire methods to be marked
+@code{@@synchronized}. Note that throwing exceptions out of
+@code{@@synchronized} blocks is allowed, and will cause the guarding object
+to be unlocked properly.
+
+@item -fobjc-gc
+@opindex fobjc-gc
+Enable garbage collection (GC) in Objective-C and Objective-C++ programs.
+
+@item -freplace-objc-classes
+@opindex freplace-objc-classes
+Emit a special marker instructing @command{ld(1)} not to statically link in
+the resulting object file, and allow @command{dyld(1)} to load it in at
+run time instead. This is used in conjunction with the Fix-and-Continue
+debugging mode, where the object file in question may be recompiled and
+dynamically reloaded in the course of program execution, without the need
+to restart the program itself. Currently, Fix-and-Continue functionality
+is only available in conjunction with the NeXT runtime on Mac OS X 10.3
+and later.
+
+@item -fzero-link
+@opindex fzero-link
+When compiling for the NeXT runtime, the compiler ordinarily replaces calls
+to @code{objc_getClass("@dots{}")} (when the name of the class is known at
+compile time) with static class references that get initialized at load time,
+which improves run-time performance. Specifying the @option{-fzero-link} flag
+suppresses this behavior and causes calls to @code{objc_getClass("@dots{}")}
+to be retained. This is useful in Zero-Link debugging mode, since it allows
+for individual class implementations to be modified during program execution.
@item -gen-decls
@opindex gen-decls
Dump interface declarations for all classes seen in the source file to a
file named @file{@var{sourcename}.decl}.
-@item -Wno-protocol
-@opindex Wno-protocol
-Do not warn if methods required by a protocol are not implemented
-in the class adopting it.
+@item -Wassign-intercept @r{(Objective-C and Objective-C++ only)}
+@opindex Wassign-intercept
+@opindex Wno-assign-intercept
+Warn whenever an Objective-C assignment is being intercepted by the
+garbage collector.
-@item -Wselector
+@item -Wno-protocol @r{(Objective-C and Objective-C++ only)}
+@opindex Wno-protocol
+@opindex Wprotocol
+If a class is declared to implement a protocol, a warning is issued for
+every method in the protocol that is not implemented by the class. The
+default behavior is to issue a warning for every method not explicitly
+implemented in the class, even if a method implementation is inherited
+from the superclass. If you use the @option{-Wno-protocol} option, then
+methods inherited from the superclass are considered to be implemented,
+and no warning is issued for them.
+
+@item -Wselector @r{(Objective-C and Objective-C++ only)}
@opindex Wselector
-Warn if a selector has multiple methods of different types defined.
-
-@c not documented because only avail via -Wp
-@c @item -print-objc-runtime-info
+@opindex Wno-selector
+Warn if multiple methods of different types for the same selector are
+found during compilation. The check is performed on the list of methods
+in the final stage of compilation. Additionally, a check is performed
+for each selector appearing in a @code{@@selector(@dots{})}
+expression, and a corresponding method for that selector has been found
+during compilation. Because these checks scan the method table only at
+the end of compilation, these warnings are not produced if the final
+stage of compilation is not reached, for example because an error is
+found during compilation, or because the @option{-fsyntax-only} option is
+being used.
+
+@item -Wstrict-selector-match @r{(Objective-C and Objective-C++ only)}
+@opindex Wstrict-selector-match
+@opindex Wno-strict-selector-match
+Warn if multiple methods with differing argument and/or return types are
+found for a given selector when attempting to send a message using this
+selector to a receiver of type @code{id} or @code{Class}. When this flag
+is off (which is the default behavior), the compiler will omit such warnings
+if any differences found are confined to types which share the same size
+and alignment.
+
+@item -Wundeclared-selector @r{(Objective-C and Objective-C++ only)}
+@opindex Wundeclared-selector
+@opindex Wno-undeclared-selector
+Warn if a @code{@@selector(@dots{})} expression referring to an
+undeclared selector is found. A selector is considered undeclared if no
+method with that name has been declared before the
+@code{@@selector(@dots{})} expression, either explicitly in an
+@code{@@interface} or @code{@@protocol} declaration, or implicitly in
+an @code{@@implementation} section. This option always performs its
+checks as soon as a @code{@@selector(@dots{})} expression is found,
+while @option{-Wselector} only performs its checks in the final stage of
+compilation. This also enforces the coding style convention
+that methods and selectors must be declared before being used.
+
+@item -print-objc-runtime-info
+@opindex print-objc-runtime-info
+Generate C header describing the largest structure that is passed by
+value, if any.
@end table
prefix) for physical lines that result from the process of breaking
a message which is too long to fit on a single line.
+@item -fdiagnostics-show-option
+@opindex fdiagnostics-show-option
+This option instructs the diagnostic machinery to add text to each
+diagnostic emitted, which indicates which command line option directly
+controls that diagnostic, when such an option is known to the
+diagnostic machinery.
+
+@item -Wcoverage-mismatch
+@opindex Wcoverage-mismatch
+Warn if feedback profiles do not match when using the
+@option{-fprofile-use} option.
+If a source file was changed between @option{-fprofile-gen} and
+@option{-fprofile-use}, the files with the profile feedback can fail
+to match the source file and GCC can not use the profile feedback
+information. By default, GCC emits an error message in this case.
+The option @option{-Wcoverage-mismatch} emits a warning instead of an
+error. GCC does not use appropriate feedback profiles, so using this
+option can result in poorly optimized code. This option is useful
+only in the case of very minor changes such as bug fixes to an
+existing code-base.
+
@end table
@node Warning Options
are not inherently erroneous but which are risky or suggest there
may have been an error.
-You can request many specific warnings with options beginning @samp{-W},
-for example @option{-Wimplicit} to request warnings on implicit
-declarations. Each of these specific warning options also has a
-negative form beginning @samp{-Wno-} to turn off warnings;
-for example, @option{-Wno-implicit}. This manual lists only one of the
-two forms, whichever is not the default.
-
-The following options control the amount and kinds of warnings produced
-by GCC; for further, language-specific options also refer to
-@ref{C++ Dialect Options} and @ref{Objective-C Dialect Options}.
+The following language-independent options do not enable specific
+warnings but control the kinds of diagnostics produced by GCC.
@table @gcctabopt
@cindex syntax checking
@opindex fsyntax-only
Check the code for syntax errors, but don't do anything beyond that.
+@item -w
+@opindex w
+Inhibit all warning messages.
+
+@item -Werror
+@opindex Werror
+@opindex Wno-error
+Make all warnings into errors.
+
+@item -Werror=
+@opindex Werror=
+@opindex Wno-error=
+Make the specified warning into an error. The specifier for a warning
+is appended, for example @option{-Werror=switch} turns the warnings
+controlled by @option{-Wswitch} into errors. This switch takes a
+negative form, to be used to negate @option{-Werror} for specific
+warnings, for example @option{-Wno-error=switch} makes
+@option{-Wswitch} warnings not be errors, even when @option{-Werror}
+is in effect. You can use the @option{-fdiagnostics-show-option}
+option to have each controllable warning amended with the option which
+controls it, to determine what to use with this option.
+
+Note that specifying @option{-Werror=}@var{foo} automatically implies
+@option{-W}@var{foo}. However, @option{-Wno-error=}@var{foo} does not
+imply anything.
+
+@item -Wfatal-errors
+@opindex Wfatal-errors
+@opindex Wno-fatal-errors
+This option causes the compiler to abort compilation on the first error
+occurred rather than trying to keep going and printing further error
+messages.
+
+@end table
+
+You can request many specific warnings with options beginning
+@samp{-W}, for example @option{-Wimplicit} to request warnings on
+implicit declarations. Each of these specific warning options also
+has a negative form beginning @samp{-Wno-} to turn off warnings; for
+example, @option{-Wno-implicit}. This manual lists only one of the
+two forms, whichever is not the default. For further,
+language-specific options also refer to @ref{C++ Dialect Options} and
+@ref{Objective-C and Objective-C++ Dialect Options}.
+
+@table @gcctabopt
@item -pedantic
@opindex pedantic
Issue all the warnings demanded by strict ISO C and ISO C++;
Like @option{-pedantic}, except that errors are produced rather than
warnings.
-@item -w
-@opindex w
-Inhibit all warning messages.
+@item -Wall
+@opindex Wall
+@opindex Wno-all
+This enables all the warnings about constructions that some users
+consider questionable, and that are easy to avoid (or modify to
+prevent the warning), even in conjunction with macros. This also
+enables some language-specific warnings described in @ref{C++ Dialect
+Options} and @ref{Objective-C and Objective-C++ Dialect Options}.
+
+@option{-Wall} turns on the following warning flags:
+
+@gccoptlist{-Waddress @gol
+-Warray-bounds @r{(only with} @option{-O2}@r{)} @gol
+-Wc++0x-compat @gol
+-Wchar-subscripts @gol
+-Wimplicit-int @gol
+-Wimplicit-function-declaration @gol
+-Wcomment @gol
+-Wformat @gol
+-Wmain @r{(only for C/ObjC and unless} @option{-ffreestanding}@r{)} @gol
+-Wmissing-braces @gol
+-Wnonnull @gol
+-Wparentheses @gol
+-Wpointer-sign @gol
+-Wreorder @gol
+-Wreturn-type @gol
+-Wsequence-point @gol
+-Wsign-compare @r{(only in C++)} @gol
+-Wstrict-aliasing @gol
+-Wstrict-overflow=1 @gol
+-Wswitch @gol
+-Wtrigraphs @gol
+-Wuninitialized @gol
+-Wunknown-pragmas @gol
+-Wunused-function @gol
+-Wunused-label @gol
+-Wunused-value @gol
+-Wunused-variable @gol
+-Wvolatile-register-var @gol
+}
+
+Note that some warning flags are not implied by @option{-Wall}. Some of
+them warn about constructions that users generally do not consider
+questionable, but which occasionally you might wish to check for;
+others warn about constructions that are necessary or hard to avoid in
+some cases, and there is no simple way to modify the code to suppress
+the warning. Some of them are enabled by @option{-Wextra} but many of
+them must be enabled individually.
+
+@item -Wextra
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+This enables some extra warning flags that are not enabled by
+@option{-Wall}. (This option used to be called @option{-W}. The older
+name is still supported, but the newer name is more descriptive.)
+
+@gccoptlist{-Wclobbered @gol
+-Wempty-body @gol
+-Wignored-qualifiers @gol
+-Wmissing-field-initializers @gol
+-Wmissing-parameter-type @r{(C only)} @gol
+-Wold-style-declaration @r{(C only)} @gol
+-Woverride-init @gol
+-Wsign-compare @gol
+-Wtype-limits @gol
+-Wuninitialized @gol
+-Wunused-parameter @r{(only with} @option{-Wunused} @r{or} @option{-Wall}@r{)} @gol
+}
+
+The option @option{-Wextra} also prints warning messages for the
+following cases:
+
+@itemize @bullet
+
+@item
+A pointer is compared against integer zero with @samp{<}, @samp{<=},
+@samp{>}, or @samp{>=}.
+
+@item
+(C++ only) An enumerator and a non-enumerator both appear in a
+conditional expression.
+
+@item
+(C++ only) Ambiguous virtual bases.
+
+@item
+(C++ only) Subscripting an array which has been declared @samp{register}.
+
+@item
+(C++ only) Taking the address of a variable which has been declared
+@samp{register}.
-@item -Wno-import
-@opindex Wno-import
-Inhibit warning messages about the use of @samp{#import}.
+@item
+(C++ only) A base class is not initialized in a derived class' copy
+constructor.
+
+@end itemize
@item -Wchar-subscripts
@opindex Wchar-subscripts
+@opindex Wno-char-subscripts
Warn if an array subscript has type @code{char}. This is a common cause
of error, as programmers often forget that this type is signed on some
machines.
+This warning is enabled by @option{-Wall}.
@item -Wcomment
@opindex Wcomment
+@opindex Wno-comment
Warn whenever a comment-start sequence @samp{/*} appears in a @samp{/*}
comment, or whenever a Backslash-Newline appears in a @samp{//} comment.
+This warning is enabled by @option{-Wall}.
@item -Wformat
@opindex Wformat
+@opindex Wno-format
+@opindex ffreestanding
+@opindex fno-builtin
Check calls to @code{printf} and @code{scanf}, etc., to make sure that
the arguments supplied have types appropriate to the format string
specified, and that the conversions specified in the format string make
sense. This includes standard functions, and others specified by format
attributes (@pxref{Function Attributes}), in the @code{printf},
@code{scanf}, @code{strftime} and @code{strfmon} (an X/Open extension,
-not in the C standard) families.
+not in the C standard) families (or other target-specific families).
+Which functions are checked without format attributes having been
+specified depends on the standard version selected, and such checks of
+functions without the attribute specified are disabled by
+@option{-ffreestanding} or @option{-fno-builtin}.
The formats are checked against the format features supported by GNU
-libc version 2.2. These include all ISO C89 and C99 features, as well
+libc version 2.2. These include all ISO C90 and C99 features, as well
as features from the Single Unix Specification and some BSD and GNU
extensions. Other library implementations may not support all these
features; GCC does not support warning about features that go beyond a
since those are not in any version of the C standard). @xref{C Dialect
Options,,Options Controlling C Dialect}.
+Since @option{-Wformat} also checks for null format arguments for
+several functions, @option{-Wformat} also implies @option{-Wnonnull}.
+
@option{-Wformat} is included in @option{-Wall}. For more control over some
-aspects of format checking, the options @option{-Wno-format-y2k},
-@option{-Wno-format-extra-args}, @option{-Wformat-nonliteral},
-@option{-Wformat-security} and @option{-Wformat=2} are available, but are
-not included in @option{-Wall}.
+aspects of format checking, the options @option{-Wformat-y2k},
+@option{-Wno-format-extra-args}, @option{-Wno-format-zero-length},
+@option{-Wformat-nonliteral}, @option{-Wformat-security}, and
+@option{-Wformat=2} are available, but are not included in @option{-Wall}.
-@item -Wno-format-y2k
+@item -Wformat-y2k
+@opindex Wformat-y2k
@opindex Wno-format-y2k
-If @option{-Wformat} is specified, do not warn about @code{strftime}
+If @option{-Wformat} is specified, also warn about @code{strftime}
formats which may yield only a two-digit year.
+@item -Wno-format-contains-nul
+@opindex Wno-format-contains-nul
+@opindex Wformat-contains-nul
+If @option{-Wformat} is specified, do not warn about format strings that
+contain NUL bytes.
+
@item -Wno-format-extra-args
@opindex Wno-format-extra-args
+@opindex Wformat-extra-args
If @option{-Wformat} is specified, do not warn about excess arguments to a
@code{printf} or @code{scanf} format function. The C standard specifies
that such arguments are ignored.
warning if the unused arguments are all pointers, since the Single
Unix Specification says that such unused arguments are allowed.
+@item -Wno-format-zero-length @r{(C and Objective-C only)}
+@opindex Wno-format-zero-length
+@opindex Wformat-zero-length
+If @option{-Wformat} is specified, do not warn about zero-length formats.
+The C standard specifies that zero-length formats are allowed.
+
@item -Wformat-nonliteral
@opindex Wformat-nonliteral
+@opindex Wno-format-nonliteral
If @option{-Wformat} is specified, also warn if the format string is not a
string literal and so cannot be checked, unless the format function
takes its format arguments as a @code{va_list}.
@item -Wformat-security
@opindex Wformat-security
+@opindex Wno-format-security
If @option{-Wformat} is specified, also warn about uses of format
functions that represent possible security problems. At present, this
warns about calls to @code{printf} and @code{scanf} functions where the
@item -Wformat=2
@opindex Wformat=2
+@opindex Wno-format=2
Enable @option{-Wformat} plus format checks not included in
@option{-Wformat}. Currently equivalent to @samp{-Wformat
--Wformat-nonliteral -Wformat-security}.
-
-@item -Wimplicit-int
-@opindex Wimplicit-int
-Warn when a declaration does not specify a type.
+-Wformat-nonliteral -Wformat-security -Wformat-y2k}.
-@item -Wimplicit-function-declaration
-@itemx -Werror-implicit-function-declaration
-@opindex Wimplicit-function-declaration
-@opindex Werror-implicit-function-declaration
-Give a warning (or error) whenever a function is used before being
-declared.
+@item -Wnonnull @r{(C and Objective-C only)}
+@opindex Wnonnull
+@opindex Wno-nonnull
+Warn about passing a null pointer for arguments marked as
+requiring a non-null value by the @code{nonnull} function attribute.
-@item -Wimplicit
-@opindex Wimplicit
-Same as @option{-Wimplicit-int} and @option{-Wimplicit-function-declaration}.
+@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It
+can be disabled with the @option{-Wno-nonnull} option.
-@item -Wmain
-@opindex Wmain
-Warn if the type of @samp{main} is suspicious. @samp{main} should be a
-function with external linkage, returning int, taking either zero
-arguments, two, or three arguments of appropriate types.
+@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)}
+@opindex Winit-self
+@opindex Wno-init-self
+Warn about uninitialized variables which are initialized with themselves.
+Note this option can only be used with the @option{-Wuninitialized} option.
+
+For example, GCC will warn about @code{i} being uninitialized in the
+following snippet only when @option{-Winit-self} has been specified:
+@smallexample
+@group
+int f()
+@{
+ int i = i;
+ return i;
+@}
+@end group
+@end smallexample
+
+@item -Wimplicit-int @r{(C and Objective-C only)}
+@opindex Wimplicit-int
+@opindex Wno-implicit-int
+Warn when a declaration does not specify a type.
+This warning is enabled by @option{-Wall}.
+
+@item -Wimplicit-function-declaration @r{(C and Objective-C only)}
+@opindex Wimplicit-function-declaration
+@opindex Wno-implicit-function-declaration
+Give a warning whenever a function is used before being declared. In
+C99 mode (@option{-std=c99} or @option{-std=gnu99}), this warning is
+enabled by default and it is made into an error by
+@option{-pedantic-errors}. This warning is also enabled by
+@option{-Wall}.
+
+@item -Wimplicit
+@opindex Wimplicit
+@opindex Wno-implicit
+Same as @option{-Wimplicit-int} and @option{-Wimplicit-function-declaration}.
+This warning is enabled by @option{-Wall}.
+
+@item -Wignored-qualifiers @r{(C and C++ only)}
+@opindex Wignored-qualifiers
+@opindex Wno-ignored-qualifiers
+Warn if the return type of a function has a type qualifier
+such as @code{const}. For ISO C such a type qualifier has no effect,
+since the value returned by a function is not an lvalue.
+For C++, the warning is only emitted for scalar types or @code{void}.
+ISO C prohibits qualified @code{void} return types on function
+definitions, so such return types always receive a warning
+even without this option.
+
+This warning is also enabled by @option{-Wextra}.
+
+@item -Wmain
+@opindex Wmain
+@opindex Wno-main
+Warn if the type of @samp{main} is suspicious. @samp{main} should be
+a function with external linkage, returning int, taking either zero
+arguments, two, or three arguments of appropriate types. This warning
+is enabled by default in C++ and is enabled by either @option{-Wall}
+or @option{-pedantic}.
@item -Wmissing-braces
@opindex Wmissing-braces
+@opindex Wno-missing-braces
Warn if an aggregate or union initializer is not fully bracketed. In
the following example, the initializer for @samp{a} is not fully
bracketed, but that for @samp{b} is fully bracketed.
int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @};
@end smallexample
+This warning is enabled by @option{-Wall}.
+
+@item -Wmissing-include-dirs @r{(C, C++, Objective-C and Objective-C++ only)}
+@opindex Wmissing-include-dirs
+@opindex Wno-missing-include-dirs
+Warn if a user-supplied include directory does not exist.
+
@item -Wparentheses
@opindex Wparentheses
+@opindex Wno-parentheses
Warn if parentheses are omitted in certain contexts, such
as when there is an assignment in a context where a truth value
is expected, or when operators are nested whose precedence people
often get confused about.
+Also warn if a comparison like @samp{x<=y<=z} appears; this is
+equivalent to @samp{(x<=y ? 1 : 0) <= z}, which is a different
+interpretation from that of ordinary mathematical notation.
+
Also warn about constructions where there may be confusion to which
@code{if} statement an @code{else} branch belongs. Here is an example of
such a case:
@end group
@end smallexample
-In C, every @code{else} branch belongs to the innermost possible @code{if}
-statement, which in this example is @code{if (b)}. This is often not
-what the programmer expected, as illustrated in the above example by
-indentation the programmer chose. When there is the potential for this
-confusion, GCC will issue a warning when this flag is specified.
-To eliminate the warning, add explicit braces around the innermost
-@code{if} statement so there is no way the @code{else} could belong to
-the enclosing @code{if}. The resulting code would look like this:
+In C/C++, every @code{else} branch belongs to the innermost possible
+@code{if} statement, which in this example is @code{if (b)}. This is
+often not what the programmer expected, as illustrated in the above
+example by indentation the programmer chose. When there is the
+potential for this confusion, GCC will issue a warning when this flag
+is specified. To eliminate the warning, add explicit braces around
+the innermost @code{if} statement so there is no way the @code{else}
+could belong to the enclosing @code{if}. The resulting code would
+look like this:
@smallexample
@group
@end group
@end smallexample
+This warning is enabled by @option{-Wall}.
+
@item -Wsequence-point
@opindex Wsequence-point
+@opindex Wno-sequence-point
Warn about code that may have undefined semantics because of violations
-of sequence point rules in the C standard.
-
-The C standard defines the order in which expressions in a C program are
-evaluated in terms of @dfn{sequence points}, which represent a partial
-ordering between the execution of parts of the program: those executed
-before the sequence point, and those executed after it. These occur
-after the evaluation of a full expression (one which is not part of a
-larger expression), after the evaluation of the first operand of a
+of sequence point rules in the C and C++ standards.
+
+The C and C++ standards defines the order in which expressions in a C/C++
+program are evaluated in terms of @dfn{sequence points}, which represent
+a partial ordering between the execution of parts of the program: those
+executed before the sequence point, and those executed after it. These
+occur after the evaluation of a full expression (one which is not part
+of a larger expression), after the evaluation of the first operand of a
@code{&&}, @code{||}, @code{? :} or @code{,} (comma) operator, before a
function is called (but after the evaluation of its arguments and the
expression denoting the called function), and in certain other places.
It is not specified when between sequence points modifications to the
values of objects take effect. Programs whose behavior depends on this
-have undefined behavior; the C standard specifies that ``Between the
-previous and next sequence point an object shall have its stored value
-modified at most once by the evaluation of an expression. Furthermore,
-the prior value shall be read only to determine the value to be
-stored.''. If a program breaks these rules, the results on any
+have undefined behavior; the C and C++ standards specify that ``Between
+the previous and next sequence point an object shall have its stored
+value modified at most once by the evaluation of an expression.
+Furthermore, the prior value shall be read only to determine the value
+to be stored.''. If a program breaks these rules, the results on any
particular implementation are entirely unpredictable.
Examples of code with undefined behavior are @code{a = a++;}, @code{a[n]
result, but in general it has been found fairly effective at detecting
this sort of problem in programs.
-The present implementation of this option only works for C programs. A
-future implementation may also work for C++ programs.
-
-The C standard is worded confusingly, therefore there is some debate
+The standard is worded confusingly, therefore there is some debate
over the precise meaning of the sequence point rules in subtle cases.
Links to discussions of the problem, including proposed formal
-definitions, may be found on our readings page, at
+definitions, may be found on the GCC readings page, at
@w{@uref{http://gcc.gnu.org/readings.html}}.
+This warning is enabled by @option{-Wall} for C and C++.
+
@item -Wreturn-type
@opindex Wreturn-type
-Warn whenever a function is defined with a return-type that defaults to
-@code{int}. Also warn about any @code{return} statement with no
-return-value in a function whose return-type is not @code{void}.
+@opindex Wno-return-type
+Warn whenever a function is defined with a return-type that defaults
+to @code{int}. Also warn about any @code{return} statement with no
+return-value in a function whose return-type is not @code{void}
+(falling off the end of the function body is considered returning
+without a value), and about a @code{return} statement with a
+expression in a function whose return-type is @code{void}.
For C++, a function without return type always produces a diagnostic
message, even when @option{-Wno-return-type} is specified. The only
exceptions are @samp{main} and functions defined in system headers.
+This warning is enabled by @option{-Wall}.
+
@item -Wswitch
@opindex Wswitch
-Warn whenever a @code{switch} statement has an index of enumeral type
+@opindex Wno-switch
+Warn whenever a @code{switch} statement has an index of enumerated type
and lacks a @code{case} for one or more of the named codes of that
enumeration. (The presence of a @code{default} label prevents this
warning.) @code{case} labels outside the enumeration range also
provoke warnings when this option is used.
+This warning is enabled by @option{-Wall}.
+
+@item -Wswitch-default
+@opindex Wswitch-default
+@opindex Wno-switch-default
+Warn whenever a @code{switch} statement does not have a @code{default}
+case.
+
+@item -Wswitch-enum
+@opindex Wswitch-enum
+@opindex Wno-switch-enum
+Warn whenever a @code{switch} statement has an index of enumerated type
+and lacks a @code{case} for one or more of the named codes of that
+enumeration. @code{case} labels outside the enumeration range also
+provoke warnings when this option is used.
+
+@item -Wsync-nand @r{(C and C++ only)}
+@opindex Wsync-nand
+@opindex Wno-sync-nand
+Warn when @code{__sync_fetch_and_nand} and @code{__sync_nand_and_fetch}
+built-in functions are used. These functions changed semantics in GCC 4.4.
@item -Wtrigraphs
@opindex Wtrigraphs
+@opindex Wno-trigraphs
Warn if any trigraphs are encountered that might change the meaning of
the program (trigraphs within comments are not warned about).
+This warning is enabled by @option{-Wall}.
@item -Wunused-function
@opindex Wunused-function
+@opindex Wno-unused-function
Warn whenever a static function is declared but not defined or a
-non\-inline static function is unused.
+non-inline static function is unused.
+This warning is enabled by @option{-Wall}.
@item -Wunused-label
@opindex Wunused-label
+@opindex Wno-unused-label
Warn whenever a label is declared but not used.
+This warning is enabled by @option{-Wall}.
To suppress this warning use the @samp{unused} attribute
(@pxref{Variable Attributes}).
@item -Wunused-parameter
@opindex Wunused-parameter
+@opindex Wno-unused-parameter
Warn whenever a function parameter is unused aside from its declaration.
To suppress this warning use the @samp{unused} attribute
@item -Wunused-variable
@opindex Wunused-variable
+@opindex Wno-unused-variable
Warn whenever a local variable or non-constant static variable is unused
-aside from its declaration
+aside from its declaration.
+This warning is enabled by @option{-Wall}.
To suppress this warning use the @samp{unused} attribute
(@pxref{Variable Attributes}).
@item -Wunused-value
@opindex Wunused-value
-Warn whenever a statement computes a result that is explicitly not used.
+@opindex Wno-unused-value
+Warn whenever a statement computes a result that is explicitly not
+used. To suppress this warning cast the unused expression to
+@samp{void}. This includes an expression-statement or the left-hand
+side of a comma expression that contains no side effects. For example,
+an expression such as @samp{x[i,j]} will cause a warning, while
+@samp{x[(void)i,j]} will not.
-To suppress this warning cast the expression to @samp{void}.
+This warning is enabled by @option{-Wall}.
@item -Wunused
@opindex Wunused
-All all the above @option{-Wunused} options combined.
+@opindex Wno-unused
+All the above @option{-Wunused} options combined.
In order to get a warning about an unused function parameter, you must
-either specify @samp{-W -Wunused} or separately specify
-@option{-Wunused-parameter}.
+either specify @samp{-Wextra -Wunused} (note that @samp{-Wall} implies
+@samp{-Wunused}), or separately specify @option{-Wunused-parameter}.
@item -Wuninitialized
@opindex Wuninitialized
-Warn if an automatic variable is used without first being initialized or
-if a variable may be clobbered by a @code{setjmp} call.
-
-These warnings are possible only in optimizing compilation,
-because they require data flow information that is computed only
-when optimizing. If you don't specify @option{-O}, you simply won't
-get these warnings.
-
-These warnings occur only for variables that are candidates for
-register allocation. Therefore, they do not occur for a variable that
-is declared @code{volatile}, or whose address is taken, or whose size
-is other than 1, 2, 4 or 8 bytes. Also, they do not occur for
-structures, unions or arrays, even when they are in registers.
+@opindex Wno-uninitialized
+Warn if an automatic variable is used without first being initialized
+or if a variable may be clobbered by a @code{setjmp} call. In C++,
+warn if a non-static reference or non-static @samp{const} member
+appears in a class without constructors.
+
+If you want to warn about code which uses the uninitialized value of the
+variable in its own initializer, use the @option{-Winit-self} option.
+
+These warnings occur for individual uninitialized or clobbered
+elements of structure, union or array variables as well as for
+variables which are uninitialized or clobbered as a whole. They do
+not occur for variables or elements declared @code{volatile}. Because
+these warnings depend on optimization, the exact variables or elements
+for which there are warnings will depend on the precise optimization
+options and version of GCC used.
Note that there may be no warning about a variable that is used only
to compute a value that itself is never used, because such
you use that never return as @code{noreturn}. @xref{Function
Attributes}.
-@item -Wreorder @r{(C++ only)}
-@opindex Wreorder
-@cindex reordering, warning
-@cindex warning for reordering of member initializers
-Warn when the order of member initializers given in the code does not
-match the order in which they must be executed. For instance:
+This warning is enabled by @option{-Wall} or @option{-Wextra}.
@item -Wunknown-pragmas
@opindex Wunknown-pragmas
+@opindex Wno-unknown-pragmas
@cindex warning for unknown pragmas
@cindex unknown pragmas, warning
@cindex pragmas, warning of unknown
for unknown pragmas in system header files. This is not the case if
the warnings were only enabled by the @option{-Wall} command line option.
-@item -Wall
-@opindex Wall
-All of the above @samp{-W} options combined. This enables all the
-warnings about constructions that some users consider questionable, and
-that are easy to avoid (or modify to prevent the warning), even in
-conjunction with macros.
+@item -Wno-pragmas
+@opindex Wno-pragmas
+@opindex Wpragmas
+Do not warn about misuses of pragmas, such as incorrect parameters,
+invalid syntax, or conflicts between pragmas. See also
+@samp{-Wunknown-pragmas}.
+
+@item -Wstrict-aliasing
+@opindex Wstrict-aliasing
+@opindex Wno-strict-aliasing
+This option is only active when @option{-fstrict-aliasing} is active.
+It warns about code which might break the strict aliasing rules that the
+compiler is using for optimization. The warning does not catch all
+cases, but does attempt to catch the more common pitfalls. It is
+included in @option{-Wall}.
+It is equivalent to @option{-Wstrict-aliasing=3}
+
+@item -Wstrict-aliasing=n
+@opindex Wstrict-aliasing=n
+@opindex Wno-strict-aliasing=n
+This option is only active when @option{-fstrict-aliasing} is active.
+It warns about code which might break the strict aliasing rules that the
+compiler is using for optimization.
+Higher levels correspond to higher accuracy (fewer false positives).
+Higher levels also correspond to more effort, similar to the way -O works.
+@option{-Wstrict-aliasing} is equivalent to @option{-Wstrict-aliasing=n},
+with n=3.
+
+Level 1: Most aggressive, quick, least accurate.
+Possibly useful when higher levels
+do not warn but -fstrict-aliasing still breaks the code, as it has very few
+false negatives. However, it has many false positives.
+Warns for all pointer conversions between possibly incompatible types,
+even if never dereferenced. Runs in the frontend only.
+
+Level 2: Aggressive, quick, not too precise.
+May still have many false positives (not as many as level 1 though),
+and few false negatives (but possibly more than level 1).
+Unlike level 1, it only warns when an address is taken. Warns about
+incomplete types. Runs in the frontend only.
+
+Level 3 (default for @option{-Wstrict-aliasing}):
+Should have very few false positives and few false
+negatives. Slightly slower than levels 1 or 2 when optimization is enabled.
+Takes care of the common punn+dereference pattern in the frontend:
+@code{*(int*)&some_float}.
+If optimization is enabled, it also runs in the backend, where it deals
+with multiple statement cases using flow-sensitive points-to information.
+Only warns when the converted pointer is dereferenced.
+Does not warn about incomplete types.
+
+@item -Wstrict-overflow
+@itemx -Wstrict-overflow=@var{n}
+@opindex Wstrict-overflow
+@opindex Wno-strict-overflow
+This option is only active when @option{-fstrict-overflow} is active.
+It warns about cases where the compiler optimizes based on the
+assumption that signed overflow does not occur. Note that it does not
+warn about all cases where the code might overflow: it only warns
+about cases where the compiler implements some optimization. Thus
+this warning depends on the optimization level.
+
+An optimization which assumes that signed overflow does not occur is
+perfectly safe if the values of the variables involved are such that
+overflow never does, in fact, occur. Therefore this warning can
+easily give a false positive: a warning about code which is not
+actually a problem. To help focus on important issues, several
+warning levels are defined. No warnings are issued for the use of
+undefined signed overflow when estimating how many iterations a loop
+will require, in particular when determining whether a loop will be
+executed at all.
-@item -Wdiv-by-zero
+@table @gcctabopt
+@item -Wstrict-overflow=1
+Warn about cases which are both questionable and easy to avoid. For
+example: @code{x + 1 > x}; with @option{-fstrict-overflow}, the
+compiler will simplify this to @code{1}. This level of
+@option{-Wstrict-overflow} is enabled by @option{-Wall}; higher levels
+are not, and must be explicitly requested.
+
+@item -Wstrict-overflow=2
+Also warn about other cases where a comparison is simplified to a
+constant. For example: @code{abs (x) >= 0}. This can only be
+simplified when @option{-fstrict-overflow} is in effect, because
+@code{abs (INT_MIN)} overflows to @code{INT_MIN}, which is less than
+zero. @option{-Wstrict-overflow} (with no level) is the same as
+@option{-Wstrict-overflow=2}.
+
+@item -Wstrict-overflow=3
+Also warn about other cases where a comparison is simplified. For
+example: @code{x + 1 > 1} will be simplified to @code{x > 0}.
+
+@item -Wstrict-overflow=4
+Also warn about other simplifications not covered by the above cases.
+For example: @code{(x * 10) / 5} will be simplified to @code{x * 2}.
+
+@item -Wstrict-overflow=5
+Also warn about cases where the compiler reduces the magnitude of a
+constant involved in a comparison. For example: @code{x + 2 > y} will
+be simplified to @code{x + 1 >= y}. This is reported only at the
+highest warning level because this simplification applies to many
+comparisons, so this warning level will give a very large number of
+false positives.
+@end table
+
+@item -Warray-bounds
+@opindex Wno-array-bounds
+@opindex Warray-bounds
+This option is only active when @option{-ftree-vrp} is active
+(default for -O2 and above). It warns about subscripts to arrays
+that are always out of bounds. This warning is enabled by @option{-Wall}.
+
+@item -Wno-div-by-zero
@opindex Wno-div-by-zero
@opindex Wdiv-by-zero
-Warn about compile-time integer division by zero. This is default. To
-inhibit the warning messages, use @option{-Wno-div-by-zero}. Floating
-point division by zero is not warned about, as it can be a legitimate
-way of obtaining infinities and NaNs.
-
-@item -Wmultichar
-@opindex Wno-multichar
-@opindex Wmultichar
-Warn if a multicharacter constant (@samp{'FOOF'}) is used. This is
-default. To inhibit the warning messages, use @option{-Wno-multichar}.
-Usually they indicate a typo in the user's code, as they have
-implementation-defined values, and should not be used in portable code.
+Do not warn about compile-time integer division by zero. Floating point
+division by zero is not warned about, as it can be a legitimate way of
+obtaining infinities and NaNs.
@item -Wsystem-headers
@opindex Wsystem-headers
+@opindex Wno-system-headers
@cindex warnings from system headers
@cindex system headers, warnings from
Print warning messages for constructs found in system header files.
code. However, note that using @option{-Wall} in conjunction with this
option will @emph{not} warn about unknown pragmas in system
headers---for that, @option{-Wunknown-pragmas} must also be used.
-@end table
-
-The following @option{-W@dots{}} options are not implied by @option{-Wall}.
-Some of them warn about constructions that users generally do not
-consider questionable, but which occasionally you might wish to check
-for; others warn about constructions that are necessary or hard to avoid
-in some cases, and there is no simple way to modify the code to suppress
-the warning.
-
-@table @gcctabopt
-@item -W
-@opindex W
-Print extra warning messages for these events:
-
-@itemize @bullet
-@item
-A function can return either with or without a value. (Falling
-off the end of the function body is considered returning without
-a value.) For example, this function would evoke such a
-warning:
-
-@smallexample
-@group
-foo (a)
-@{
- if (a > 0)
- return a;
-@}
-@end group
-@end smallexample
-
-@item
-An expression-statement or the left-hand side of a comma expression
-contains no side effects.
-To suppress the warning, cast the unused expression to void.
-For example, an expression such as @samp{x[i,j]} will cause a warning,
-but @samp{x[(void)i,j]} will not.
-
-@item
-An unsigned value is compared against zero with @samp{<} or @samp{<=}.
-
-@item
-A comparison like @samp{x<=y<=z} appears; this is equivalent to
-@samp{(x<=y ? 1 : 0) <= z}, which is a different interpretation from
-that of ordinary mathematical notation.
-
-@item
-Storage-class specifiers like @code{static} are not the first things in
-a declaration. According to the C Standard, this usage is obsolescent.
-
-@item
-The return type of a function has a type qualifier such as @code{const}.
-Such a type qualifier has no effect, since the value returned by a
-function is not an lvalue. (But don't warn about the GNU extension of
-@code{volatile void} return types. That extension will be warned about
-if @option{-pedantic} is specified.)
-
-@item
-If @option{-Wall} or @option{-Wunused} is also specified, warn about unused
-arguments.
-
-@item
-A comparison between signed and unsigned values could produce an
-incorrect result when the signed value is converted to unsigned.
-(But don't warn if @option{-Wno-sign-compare} is also specified.)
-
-@item
-An aggregate has a partly bracketed initializer.
-For example, the following code would evoke such a warning,
-because braces are missing around the initializer for @code{x.h}:
-
-@smallexample
-struct s @{ int f, g; @};
-struct t @{ struct s h; int i; @};
-struct t x = @{ 1, 2, 3 @};
-@end smallexample
-
-@item
-An aggregate has an initializer which does not initialize all members.
-For example, the following code would cause such a warning, because
-@code{x.h} would be implicitly initialized to zero:
-
-@smallexample
-struct s @{ int f, g, h; @};
-struct s x = @{ 3, 4 @};
-@end smallexample
-@end itemize
@item -Wfloat-equal
@opindex Wfloat-equal
+@opindex Wno-float-equal
Warn if floating point values are used in equality comparisons.
The idea behind this is that sometimes it is convenient (for the
programmer) to consider floating-point values as approximations to
infinitely precise real numbers. If you are doing this, then you need
-to compute (by analysing the code, or in some other way) the maximum or
+to compute (by analyzing the code, or in some other way) the maximum or
likely maximum error that the computation introduces, and allow for it
when performing comparisons (and when producing output, but that's a
different problem). In particular, instead of testing for equality, you
this is done with the relational operators, so equality comparisons are
probably mistaken.
-@item -Wtraditional @r{(C only)}
+@item -Wtraditional @r{(C and Objective-C only)}
@opindex Wtraditional
+@opindex Wno-traditional
Warn about certain constructs that behave differently in traditional and
ISO C@. Also warn about ISO C constructs that have no traditional C
equivalent, and/or problematic constructs which should be avoided.
constants.) Note, these suffixes appear in macros defined in the system
headers of most modern systems, e.g.@: the @samp{_MIN}/@samp{_MAX} macros in @code{<limits.h>}.
Use of these macros in user code might normally lead to spurious
-warnings, however gcc's integrated preprocessor has enough context to
+warnings, however GCC's integrated preprocessor has enough context to
avoid warning in these cases.
@item
Conversions by prototypes between fixed/floating point values and vice
versa. The absence of these prototypes when compiling with traditional
C would cause serious problems. This is a subset of the possible
-conversion warnings, for the full set use @option{-Wconversion}.
+conversion warnings, for the full set use @option{-Wtraditional-conversion}.
+
+@item
+Use of ISO C style function definitions. This warning intentionally is
+@emph{not} issued for prototype declarations or variadic functions
+because these ISO C features will appear in your code when using
+libiberty's traditional C compatibility macros, @code{PARAMS} and
+@code{VPARAMS}. This warning is also bypassed for nested functions
+because that feature is already a GCC extension and thus not relevant to
+traditional C compatibility.
@end itemize
+@item -Wtraditional-conversion @r{(C and Objective-C only)}
+@opindex Wtraditional-conversion
+@opindex Wno-traditional-conversion
+Warn if a prototype causes a type conversion that is different from what
+would happen to the same argument in the absence of a prototype. This
+includes conversions of fixed point to floating and vice versa, and
+conversions changing the width or signedness of a fixed point argument
+except when the same as the default promotion.
+
+@item -Wdeclaration-after-statement @r{(C and Objective-C only)}
+@opindex Wdeclaration-after-statement
+@opindex Wno-declaration-after-statement
+Warn when a declaration is found after a statement in a block. This
+construct, known from C++, was introduced with ISO C99 and is by default
+allowed in GCC@. It is not supported by ISO C90 and was not supported by
+GCC versions before GCC 3.0. @xref{Mixed Declarations}.
+
@item -Wundef
@opindex Wundef
+@opindex Wno-undef
Warn if an undefined identifier is evaluated in an @samp{#if} directive.
+@item -Wno-endif-labels
+@opindex Wno-endif-labels
+@opindex Wendif-labels
+Do not warn whenever an @samp{#else} or an @samp{#endif} are followed by text.
+
@item -Wshadow
@opindex Wshadow
+@opindex Wno-shadow
Warn whenever a local variable shadows another local variable, parameter or
global variable or whenever a built-in function is shadowed.
-@item -Wlarger-than-@var{len}
-@opindex Wlarger-than
+@item -Wlarger-than=@var{len}
+@opindex Wlarger-than=@var{len}
+@opindex Wlarger-than-@var{len}
Warn whenever an object of larger than @var{len} bytes is defined.
+@item -Wframe-larger-than=@var{len}
+@opindex Wframe-larger-than
+Warn if the size of a function frame is larger than @var{len} bytes.
+The computation done to determine the stack frame size is approximate
+and not conservative.
+The actual requirements may be somewhat greater than @var{len}
+even if you do not get a warning. In addition, any space allocated
+via @code{alloca}, variable-length arrays, or related constructs
+is not included by the compiler when determining
+whether or not to issue a warning.
+
+@item -Wunsafe-loop-optimizations
+@opindex Wunsafe-loop-optimizations
+@opindex Wno-unsafe-loop-optimizations
+Warn if the loop cannot be optimized because the compiler could not
+assume anything on the bounds of the loop indices. With
+@option{-funsafe-loop-optimizations} warn if the compiler made
+such assumptions.
+
+@item -Wno-pedantic-ms-format @r{(MinGW targets only)}
+@opindex Wno-pedantic-ms-format
+@opindex Wpedantic-ms-format
+Disables the warnings about non-ISO @code{printf} / @code{scanf} format
+width specifiers @code{I32}, @code{I64}, and @code{I} used on Windows targets
+depending on the MS runtime, when you are using the options @option{-Wformat}
+and @option{-pedantic} without gnu-extensions.
+
@item -Wpointer-arith
@opindex Wpointer-arith
+@opindex Wno-pointer-arith
Warn about anything that depends on the ``size of'' a function type or
of @code{void}. GNU C assigns these types a size of 1, for
convenience in calculations with @code{void *} pointers and pointers
-to functions.
-
-@item -Wbad-function-cast @r{(C only)}
+to functions. In C++, warn also when an arithmetic operation involves
+@code{NULL}. This warning is also enabled by @option{-pedantic}.
+
+@item -Wtype-limits
+@opindex Wtype-limits
+@opindex Wno-type-limits
+Warn if a comparison is always true or always false due to the limited
+range of the data type, but do not warn for constant expressions. For
+example, warn if an unsigned variable is compared against zero with
+@samp{<} or @samp{>=}. This warning is also enabled by
+@option{-Wextra}.
+
+@item -Wbad-function-cast @r{(C and Objective-C only)}
@opindex Wbad-function-cast
+@opindex Wno-bad-function-cast
Warn whenever a function call is cast to a non-matching type.
For example, warn if @code{int malloc()} is cast to @code{anything *}.
+@item -Wc++-compat @r{(C and Objective-C only)}
+Warn about ISO C constructs that are outside of the common subset of
+ISO C and ISO C++, e.g.@: request for implicit conversion from
+@code{void *} to a pointer to non-@code{void} type.
+
+@item -Wc++0x-compat @r{(C++ and Objective-C++ only)}
+Warn about C++ constructs whose meaning differs between ISO C++ 1998 and
+ISO C++ 200x, e.g., identifiers in ISO C++ 1998 that will become keywords
+in ISO C++ 200x. This warning is enabled by @option{-Wall}.
+
@item -Wcast-qual
@opindex Wcast-qual
+@opindex Wno-cast-qual
Warn whenever a pointer is cast so as to remove a type qualifier from
the target type. For example, warn if a @code{const char *} is cast
to an ordinary @code{char *}.
@item -Wcast-align
@opindex Wcast-align
+@opindex Wno-cast-align
Warn whenever a pointer is cast such that the required alignment of the
target is increased. For example, warn if a @code{char *} is cast to
an @code{int *} on machines where integers can only be accessed at
@item -Wwrite-strings
@opindex Wwrite-strings
+@opindex Wno-write-strings
When compiling C, give string constants the type @code{const
-char[@var{length}]} so that
-copying the address of one into a non-@code{const} @code{char *}
-pointer will get a warning; when compiling C++, warn about the
-deprecated conversion from string constants to @code{char *}.
-These warnings will help you find at
-compile time code that can try to write into a string constant, but
-only if you have been very careful about using @code{const} in
-declarations and prototypes. Otherwise, it will just be a nuisance;
-this is why we did not make @option{-Wall} request these warnings.
+char[@var{length}]} so that copying the address of one into a
+non-@code{const} @code{char *} pointer will get a warning. These
+warnings will help you find at compile time code that can try to write
+into a string constant, but only if you have been very careful about
+using @code{const} in declarations and prototypes. Otherwise, it will
+just be a nuisance. This is why we did not make @option{-Wall} request
+these warnings.
+
+When compiling C++, warn about the deprecated conversion from string
+literals to @code{char *}. This warning is enabled by default for C++
+programs.
+
+@item -Wclobbered
+@opindex Wclobbered
+@opindex Wno-clobbered
+Warn for variables that might be changed by @samp{longjmp} or
+@samp{vfork}. This warning is also enabled by @option{-Wextra}.
@item -Wconversion
@opindex Wconversion
-Warn if a prototype causes a type conversion that is different from what
-would happen to the same argument in the absence of a prototype. This
-includes conversions of fixed point to floating and vice versa, and
-conversions changing the width or signedness of a fixed point argument
-except when the same as the default promotion.
-
-Also, warn if a negative integer constant expression is implicitly
-converted to an unsigned type. For example, warn about the assignment
-@code{x = -1} if @code{x} is unsigned. But do not warn about explicit
-casts like @code{(unsigned) -1}.
+@opindex Wno-conversion
+Warn for implicit conversions that may alter a value. This includes
+conversions between real and integer, like @code{abs (x)} when
+@code{x} is @code{double}; conversions between signed and unsigned,
+like @code{unsigned ui = -1}; and conversions to smaller types, like
+@code{sqrtf (M_PI)}. Do not warn for explicit casts like @code{abs
+((int) x)} and @code{ui = (unsigned) -1}, or if the value is not
+changed by the conversion like in @code{abs (2.0)}. Warnings about
+conversions between signed and unsigned integers can be disabled by
+using @option{-Wno-sign-conversion}.
+
+For C++, also warn for conversions between @code{NULL} and non-pointer
+types; confusing overload resolution for user-defined conversions; and
+conversions that will never use a type conversion operator:
+conversions to @code{void}, the same type, a base class or a reference
+to them. Warnings about conversions between signed and unsigned
+integers are disabled by default in C++ unless
+@option{-Wsign-conversion} is explicitly enabled.
+
+@item -Wempty-body
+@opindex Wempty-body
+@opindex Wno-empty-body
+Warn if an empty body occurs in an @samp{if}, @samp{else} or @samp{do
+while} statement. This warning is also enabled by @option{-Wextra}.
+
+@item -Wenum-compare @r{(C++ and Objective-C++ only)}
+@opindex Wenum-compare
+@opindex Wno-enum-compare
+Warn about a comparison between values of different enum types. This
+warning is enabled by default.
@item -Wsign-compare
@opindex Wsign-compare
+@opindex Wno-sign-compare
@cindex warning for comparison of signed and unsigned values
@cindex comparison of signed and unsigned values, warning
@cindex signed and unsigned values, comparison warning
Warn when a comparison between signed and unsigned values could produce
an incorrect result when the signed value is converted to unsigned.
-This warning is also enabled by @option{-W}; to get the other warnings
-of @option{-W} without this warning, use @samp{-W -Wno-sign-compare}.
+This warning is also enabled by @option{-Wextra}; to get the other warnings
+of @option{-Wextra} without this warning, use @samp{-Wextra -Wno-sign-compare}.
+
+@item -Wsign-conversion
+@opindex Wsign-conversion
+@opindex Wno-sign-conversion
+Warn for implicit conversions that may change the sign of an integer
+value, like assigning a signed integer expression to an unsigned
+integer variable. An explicit cast silences the warning. In C, this
+option is enabled also by @option{-Wconversion}.
+
+@item -Waddress
+@opindex Waddress
+@opindex Wno-address
+Warn about suspicious uses of memory addresses. These include using
+the address of a function in a conditional expression, such as
+@code{void func(void); if (func)}, and comparisons against the memory
+address of a string literal, such as @code{if (x == "abc")}. Such
+uses typically indicate a programmer error: the address of a function
+always evaluates to true, so their use in a conditional usually
+indicate that the programmer forgot the parentheses in a function
+call; and comparisons against string literals result in unspecified
+behavior and are not portable in C, so they usually indicate that the
+programmer intended to use @code{strcmp}. This warning is enabled by
+@option{-Wall}.
+
+@item -Wlogical-op
+@opindex Wlogical-op
+@opindex Wno-logical-op
+Warn about suspicious uses of logical operators in expressions.
+This includes using logical operators in contexts where a
+bit-wise operator is likely to be expected.
@item -Waggregate-return
@opindex Waggregate-return
+@opindex Wno-aggregate-return
Warn if any functions that return structures or unions are defined or
called. (In languages where you can return an array, this also elicits
a warning.)
-@item -Wstrict-prototypes @r{(C only)}
+@item -Wno-attributes
+@opindex Wno-attributes
+@opindex Wattributes
+Do not warn if an unexpected @code{__attribute__} is used, such as
+unrecognized attributes, function attributes applied to variables,
+etc. This will not stop errors for incorrect use of supported
+attributes.
+
+@item -Wno-builtin-macro-redefined
+@opindex Wno-builtin-macro-redefined
+@opindex Wbuiltin-macro-redefined
+Do not warn if certain built-in macros are redefined. This suppresses
+warnings for redefinition of @code{__TIMESTAMP__}, @code{__TIME__},
+@code{__DATE__}, @code{__FILE__}, and @code{__BASE_FILE__}.
+
+@item -Wstrict-prototypes @r{(C and Objective-C only)}
@opindex Wstrict-prototypes
+@opindex Wno-strict-prototypes
Warn if a function is declared or defined without specifying the
argument types. (An old-style function definition is permitted without
a warning if preceded by a declaration which specifies the argument
types.)
-@item -Wmissing-prototypes @r{(C only)}
+@item -Wold-style-declaration @r{(C and Objective-C only)}
+@opindex Wold-style-declaration
+@opindex Wno-old-style-declaration
+Warn for obsolescent usages, according to the C Standard, in a
+declaration. For example, warn if storage-class specifiers like
+@code{static} are not the first things in a declaration. This warning
+is also enabled by @option{-Wextra}.
+
+@item -Wold-style-definition @r{(C and Objective-C only)}
+@opindex Wold-style-definition
+@opindex Wno-old-style-definition
+Warn if an old-style function definition is used. A warning is given
+even if there is a previous prototype.
+
+@item -Wmissing-parameter-type @r{(C and Objective-C only)}
+@opindex Wmissing-parameter-type
+@opindex Wno-missing-parameter-type
+A function parameter is declared without a type specifier in K&R-style
+functions:
+
+@smallexample
+void foo(bar) @{ @}
+@end smallexample
+
+This warning is also enabled by @option{-Wextra}.
+
+@item -Wmissing-prototypes @r{(C and Objective-C only)}
@opindex Wmissing-prototypes
+@opindex Wno-missing-prototypes
Warn if a global function is defined without a previous prototype
declaration. This warning is issued even if the definition itself
provides a prototype. The aim is to detect global functions that fail
@item -Wmissing-declarations
@opindex Wmissing-declarations
+@opindex Wno-missing-declarations
Warn if a global function is defined without a previous declaration.
Do so even if the definition itself provides a prototype.
Use this option to detect global functions that are not declared in
-header files.
+header files. In C++, no warnings are issued for function templates,
+or for inline functions, or for functions in anonymous namespaces.
+
+@item -Wmissing-field-initializers
+@opindex Wmissing-field-initializers
+@opindex Wno-missing-field-initializers
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+Warn if a structure's initializer has some fields missing. For
+example, the following code would cause such a warning, because
+@code{x.h} is implicitly zero:
+
+@smallexample
+struct s @{ int f, g, h; @};
+struct s x = @{ 3, 4 @};
+@end smallexample
+
+This option does not warn about designated initializers, so the following
+modification would not trigger a warning:
+
+@smallexample
+struct s @{ int f, g, h; @};
+struct s x = @{ .f = 3, .g = 4 @};
+@end smallexample
+
+This warning is included in @option{-Wextra}. To get other @option{-Wextra}
+warnings without this one, use @samp{-Wextra -Wno-missing-field-initializers}.
@item -Wmissing-noreturn
@opindex Wmissing-noreturn
+@opindex Wno-missing-noreturn
Warn about functions which might be candidates for attribute @code{noreturn}.
Note these are only possible candidates, not absolute ones. Care should
be taken to manually verify functions actually do not ever return before
@item -Wmissing-format-attribute
@opindex Wmissing-format-attribute
+@opindex Wno-missing-format-attribute
@opindex Wformat
-If @option{-Wformat} is enabled, also warn about functions which might be
-candidates for @code{format} attributes. Note these are only possible
-candidates, not absolute ones. GCC will guess that @code{format}
-attributes might be appropriate for any function that calls a function
-like @code{vprintf} or @code{vscanf}, but this might not always be the
+@opindex Wno-format
+Warn about function pointers which might be candidates for @code{format}
+attributes. Note these are only possible candidates, not absolute ones.
+GCC will guess that function pointers with @code{format} attributes that
+are used in assignment, initialization, parameter passing or return
+statements should have a corresponding @code{format} attribute in the
+resulting type. I.e.@: the left-hand side of the assignment or
+initialization, the type of the parameter variable, or the return type
+of the containing function respectively should also have a @code{format}
+attribute to avoid the warning.
+
+GCC will also warn about function definitions which might be
+candidates for @code{format} attributes. Again, these are only
+possible candidates. GCC will guess that @code{format} attributes
+might be appropriate for any function that calls a function like
+@code{vprintf} or @code{vscanf}, but this might not always be the
case, and some functions for which @code{format} attributes are
-appropriate may not be detected. This option has no effect unless
-@option{-Wformat} is enabled (possibly by @option{-Wall}).
+appropriate may not be detected.
+
+@item -Wno-multichar
+@opindex Wno-multichar
+@opindex Wmultichar
+Do not warn if a multicharacter constant (@samp{'FOOF'}) is used.
+Usually they indicate a typo in the user's code, as they have
+implementation-defined values, and should not be used in portable code.
+
+@item -Wnormalized=<none|id|nfc|nfkc>
+@opindex Wnormalized=
+@cindex NFC
+@cindex NFKC
+@cindex character set, input normalization
+In ISO C and ISO C++, two identifiers are different if they are
+different sequences of characters. However, sometimes when characters
+outside the basic ASCII character set are used, you can have two
+different character sequences that look the same. To avoid confusion,
+the ISO 10646 standard sets out some @dfn{normalization rules} which
+when applied ensure that two sequences that look the same are turned into
+the same sequence. GCC can warn you if you are using identifiers which
+have not been normalized; this option controls that warning.
+
+There are four levels of warning that GCC supports. The default is
+@option{-Wnormalized=nfc}, which warns about any identifier which is
+not in the ISO 10646 ``C'' normalized form, @dfn{NFC}. NFC is the
+recommended form for most uses.
+
+Unfortunately, there are some characters which ISO C and ISO C++ allow
+in identifiers that when turned into NFC aren't allowable as
+identifiers. That is, there's no way to use these symbols in portable
+ISO C or C++ and have all your identifiers in NFC@.
+@option{-Wnormalized=id} suppresses the warning for these characters.
+It is hoped that future versions of the standards involved will correct
+this, which is why this option is not the default.
+
+You can switch the warning off for all characters by writing
+@option{-Wnormalized=none}. You would only want to do this if you
+were using some other normalization scheme (like ``D''), because
+otherwise you can easily create bugs that are literally impossible to see.
+
+Some characters in ISO 10646 have distinct meanings but look identical
+in some fonts or display methodologies, especially once formatting has
+been applied. For instance @code{\u207F}, ``SUPERSCRIPT LATIN SMALL
+LETTER N'', will display just like a regular @code{n} which has been
+placed in a superscript. ISO 10646 defines the @dfn{NFKC}
+normalization scheme to convert all these into a standard form as
+well, and GCC will warn if your code is not in NFKC if you use
+@option{-Wnormalized=nfkc}. This warning is comparable to warning
+about every identifier that contains the letter O because it might be
+confused with the digit 0, and so is not the default, but may be
+useful as a local coding convention if the programming environment is
+unable to be fixed to display these characters distinctly.
+
+@item -Wno-deprecated
+@opindex Wno-deprecated
+@opindex Wdeprecated
+Do not warn about usage of deprecated features. @xref{Deprecated Features}.
@item -Wno-deprecated-declarations
@opindex Wno-deprecated-declarations
-Do not warn about uses of functions, variables, and types marked as
-deprecated by using the @code{deprecated} attribute.
-(@pxref{Function Attributes}, @pxref{Variable Attributes},
-@pxref{Type Attributes}.)
+@opindex Wdeprecated-declarations
+Do not warn about uses of functions (@pxref{Function Attributes}),
+variables (@pxref{Variable Attributes}), and types (@pxref{Type
+Attributes}) marked as deprecated by using the @code{deprecated}
+attribute.
+
+@item -Wno-overflow
+@opindex Wno-overflow
+@opindex Woverflow
+Do not warn about compile-time overflow in constant expressions.
+
+@item -Woverride-init @r{(C and Objective-C only)}
+@opindex Woverride-init
+@opindex Wno-override-init
+@opindex W
+@opindex Wextra
+@opindex Wno-extra
+Warn if an initialized field without side effects is overridden when
+using designated initializers (@pxref{Designated Inits, , Designated
+Initializers}).
+
+This warning is included in @option{-Wextra}. To get other
+@option{-Wextra} warnings without this one, use @samp{-Wextra
+-Wno-override-init}.
@item -Wpacked
@opindex Wpacked
+@opindex Wno-packed
Warn if a structure is given the packed attribute, but the packed
attribute has no effect on the layout or size of the structure.
Such structures may be mis-aligned for little benefit. For
@end group
@end smallexample
+@item -Wpacked-bitfield-compat
+@opindex Wpacked-bitfield-compat
+@opindex Wno-packed-bitfield-compat
+The 4.1, 4.2 and 4.3 series of GCC ignore the @code{packed} attribute
+on bit-fields of type @code{char}. This has been fixed in GCC 4.4 but
+the change can lead to differences in the structure layout. GCC
+informs you when the offset of such a field has changed in GCC 4.4.
+For example there is no longer a 4-bit padding between field @code{a}
+and @code{b} in this structure:
+
+@smallexample
+struct foo
+@{
+ char a:4;
+ char b:8;
+@} __attribute__ ((packed));
+@end smallexample
+
+This warning is enabled by default. Use
+@option{-Wno-packed-bitfield-compat} to disable this warning.
+
@item -Wpadded
@opindex Wpadded
+@opindex Wno-padded
Warn if padding is included in a structure, either to align an element
of the structure or to align the whole structure. Sometimes when this
happens it is possible to rearrange the fields of the structure to
@item -Wredundant-decls
@opindex Wredundant-decls
+@opindex Wno-redundant-decls
Warn if anything is declared more than once in the same scope, even in
cases where multiple declaration is valid and changes nothing.
-@item -Wnested-externs @r{(C only)}
+@item -Wnested-externs @r{(C and Objective-C only)}
@opindex Wnested-externs
+@opindex Wno-nested-externs
Warn if an @code{extern} declaration is encountered within a function.
@item -Wunreachable-code
@opindex Wunreachable-code
+@opindex Wno-unreachable-code
Warn if the compiler detects that code will never be executed.
This option is intended to warn when the compiler detects that at
@item -Winline
@opindex Winline
+@opindex Wno-inline
Warn if a function can not be inlined and it was declared as inline.
+Even with this option, the compiler will not warn about failures to
+inline functions declared in system headers.
+
+The compiler uses a variety of heuristics to determine whether or not
+to inline a function. For example, the compiler takes into account
+the size of the function being inlined and the amount of inlining
+that has already been done in the current function. Therefore,
+seemingly insignificant changes in the source program can cause the
+warnings produced by @option{-Winline} to appear or disappear.
+
+@item -Wno-invalid-offsetof @r{(C++ and Objective-C++ only)}
+@opindex Wno-invalid-offsetof
+@opindex Winvalid-offsetof
+Suppress warnings from applying the @samp{offsetof} macro to a non-POD
+type. According to the 1998 ISO C++ standard, applying @samp{offsetof}
+to a non-POD type is undefined. In existing C++ implementations,
+however, @samp{offsetof} typically gives meaningful results even when
+applied to certain kinds of non-POD types. (Such as a simple
+@samp{struct} that fails to be a POD type only by virtue of having a
+constructor.) This flag is for users who are aware that they are
+writing nonportable code and who have deliberately chosen to ignore the
+warning about it.
+
+The restrictions on @samp{offsetof} may be relaxed in a future version
+of the C++ standard.
+
+@item -Wno-int-to-pointer-cast @r{(C and Objective-C only)}
+@opindex Wno-int-to-pointer-cast
+@opindex Wint-to-pointer-cast
+Suppress warnings from casts to pointer type of an integer of a
+different size.
+
+@item -Wno-pointer-to-int-cast @r{(C and Objective-C only)}
+@opindex Wno-pointer-to-int-cast
+@opindex Wpointer-to-int-cast
+Suppress warnings from casts from a pointer to an integer type of a
+different size.
+
+@item -Winvalid-pch
+@opindex Winvalid-pch
+@opindex Wno-invalid-pch
+Warn if a precompiled header (@pxref{Precompiled Headers}) is found in
+the search path but can't be used.
@item -Wlong-long
@opindex Wlong-long
@option{-Wlong-long} and @option{-Wno-long-long} are taken into account
only when @option{-pedantic} flag is used.
+@item -Wvariadic-macros
+@opindex Wvariadic-macros
+@opindex Wno-variadic-macros
+Warn if variadic macros are used in pedantic ISO C90 mode, or the GNU
+alternate syntax when in pedantic ISO C99 mode. This is default.
+To inhibit the warning messages, use @option{-Wno-variadic-macros}.
+
+@item -Wvla
+@opindex Wvla
+@opindex Wno-vla
+Warn if variable length array is used in the code.
+@option{-Wno-vla} will prevent the @option{-pedantic} warning of
+the variable length array.
+
+@item -Wvolatile-register-var
+@opindex Wvolatile-register-var
+@opindex Wno-volatile-register-var
+Warn if a register variable is declared volatile. The volatile
+modifier does not inhibit all optimizations that may eliminate reads
+and/or writes to register variables. This warning is enabled by
+@option{-Wall}.
+
@item -Wdisabled-optimization
@opindex Wdisabled-optimization
+@opindex Wno-disabled-optimization
Warn if a requested optimization pass is disabled. This warning does
not generally indicate that there is anything wrong with your code; it
merely indicates that GCC's optimizers were unable to handle the code
complex; GCC will refuse to optimize programs when the optimization
itself is likely to take inordinate amounts of time.
-@item -Werror
-@opindex Werror
-Make all warnings into errors.
+@item -Wpointer-sign @r{(C and Objective-C only)}
+@opindex Wpointer-sign
+@opindex Wno-pointer-sign
+Warn for pointer argument passing or assignment with different signedness.
+This option is only supported for C and Objective-C@. It is implied by
+@option{-Wall} and by @option{-pedantic}, which can be disabled with
+@option{-Wno-pointer-sign}.
+
+@item -Wstack-protector
+@opindex Wstack-protector
+@opindex Wno-stack-protector
+This option is only active when @option{-fstack-protector} is active. It
+warns about functions that will not be protected against stack smashing.
+
+@item -Wno-mudflap
+@opindex Wno-mudflap
+Suppress warnings about constructs that cannot be instrumented by
+@option{-fmudflap}.
+
+@item -Woverlength-strings
+@opindex Woverlength-strings
+@opindex Wno-overlength-strings
+Warn about string constants which are longer than the ``minimum
+maximum'' length specified in the C standard. Modern compilers
+generally allow string constants which are much longer than the
+standard's minimum limit, but very portable programs should avoid
+using longer strings.
+
+The limit applies @emph{after} string constant concatenation, and does
+not count the trailing NUL@. In C89, the limit was 509 characters; in
+C99, it was raised to 4095. C++98 does not specify a normative
+minimum maximum, so we do not diagnose overlength strings in C++@.
+
+This option is implied by @option{-pedantic}, and can be disabled with
+@option{-Wno-overlength-strings}.
@end table
@node Debugging Options
@item -g
@opindex g
Produce debugging information in the operating system's native format
-(stabs, COFF, XCOFF, or DWARF)@. GDB can work with this debugging
+(stabs, COFF, XCOFF, or DWARF 2)@. GDB can work with this debugging
information.
On most systems that use stabs format, @option{-g} enables use of extra
crash or
refuse to read the program. If you want to control for certain whether
to generate the extra information, use @option{-gstabs+}, @option{-gstabs},
-@option{-gxcoff+}, @option{-gxcoff}, @option{-gdwarf-1+}, @option{-gdwarf-1},
-or @option{-gvms} (see below).
+@option{-gxcoff+}, @option{-gxcoff}, or @option{-gvms} (see below).
-Unlike most other C compilers, GCC allows you to use @option{-g} with
+GCC allows you to use @option{-g} with
@option{-O}. The shortcuts taken by optimized code may occasionally
produce surprising results: some variables you declared may not exist
at all; flow of control may briefly move where you did not expect it;
produces stabs debugging output which is not understood by DBX or SDB@.
On System V Release 4 systems this option requires the GNU assembler.
+@item -feliminate-unused-debug-symbols
+@opindex feliminate-unused-debug-symbols
+Produce debugging information in stabs format (if that is supported),
+for only symbols that are actually used.
+
+@item -femit-class-debug-always
+Instead of emitting debugging information for a C++ class in only one
+object file, emit it in all object files using the class. This option
+should be used only with debuggers that are unable to handle the way GCC
+normally emits debugging information for classes because using this
+option will increase the size of debugging information by as much as a
+factor of two.
+
@item -gstabs+
@opindex gstabs+
Produce debugging information in stabs format (if that is supported),
refuse to read the program, and may cause assemblers other than the GNU
assembler (GAS) to fail with an error.
-@item -gdwarf
-@opindex gdwarf
-Produce debugging information in DWARF version 1 format (if that is
-supported). This is the format used by SDB on most System V Release 4
-systems.
-
-@item -gdwarf+
-@opindex gdwarf+
-Produce debugging information in DWARF version 1 format (if that is
-supported), using GNU extensions understood only by the GNU debugger
-(GDB)@. The use of these extensions is likely to make other debuggers
-crash or refuse to read the program.
-
@item -gdwarf-2
@opindex gdwarf-2
Produce debugging information in DWARF version 2 format (if that is
-supported). This is the format used by DBX on IRIX 6.
+supported). This is the format used by DBX on IRIX 6. With this
+option, GCC uses features of DWARF version 3 when they are useful;
+version 3 is upward compatible with version 2, but may still cause
+problems for older debuggers.
@item -gvms
@opindex gvms
Request debugging information and also use @var{level} to specify how
much information. The default level is 2.
+Level 0 produces no debug information at all. Thus, @option{-g0} negates
+@option{-g}.
+
Level 1 produces minimal information, enough for making backtraces in
parts of the program that you don't plan to debug. This includes
descriptions of functions and external variables, but no information
present in the program. Some debuggers support macro expansion when
you use @option{-g3}.
-Note that in order to avoid confusion between DWARF1 debug level 2,
-and DWARF2, neither @option{-gdwarf} nor @option{-gdwarf-2} accept
-a concatenated debug level. Instead use an additional @option{-g@var{level}}
-option to change the debug level for DWARF1 or DWARF2.
-
-@cindex @code{prof}
+@option{-gdwarf-2} does not accept a concatenated debug level, because
+GCC used to support an option @option{-gdwarf} that meant to generate
+debug information in version 1 of the DWARF format (which is very
+different from version 2), and it would have been too confusing. That
+debug format is long obsolete, but the option cannot be changed now.
+Instead use an additional @option{-g@var{level}} option to change the
+debug level for DWARF2.
+
+@item -feliminate-dwarf2-dups
+@opindex feliminate-dwarf2-dups
+Compress DWARF2 debugging information by eliminating duplicated
+information about each symbol. This option only makes sense when
+generating DWARF2 debugging information with @option{-gdwarf-2}.
+
+@item -femit-struct-debug-baseonly
+Emit debug information for struct-like types
+only when the base name of the compilation source file
+matches the base name of file in which the struct was defined.
+
+This option substantially reduces the size of debugging information,
+but at significant potential loss in type information to the debugger.
+See @option{-femit-struct-debug-reduced} for a less aggressive option.
+See @option{-femit-struct-debug-detailed} for more detailed control.
+
+This option works only with DWARF 2.
+
+@item -femit-struct-debug-reduced
+Emit debug information for struct-like types
+only when the base name of the compilation source file
+matches the base name of file in which the type was defined,
+unless the struct is a template or defined in a system header.
+
+This option significantly reduces the size of debugging information,
+with some potential loss in type information to the debugger.
+See @option{-femit-struct-debug-baseonly} for a more aggressive option.
+See @option{-femit-struct-debug-detailed} for more detailed control.
+
+This option works only with DWARF 2.
+
+@item -femit-struct-debug-detailed@r{[}=@var{spec-list}@r{]}
+Specify the struct-like types
+for which the compiler will generate debug information.
+The intent is to reduce duplicate struct debug information
+between different object files within the same program.
+
+This option is a detailed version of
+@option{-femit-struct-debug-reduced} and @option{-femit-struct-debug-baseonly},
+which will serve for most needs.
+
+A specification has the syntax
+[@samp{dir:}|@samp{ind:}][@samp{ord:}|@samp{gen:}](@samp{any}|@samp{sys}|@samp{base}|@samp{none})
+
+The optional first word limits the specification to
+structs that are used directly (@samp{dir:}) or used indirectly (@samp{ind:}).
+A struct type is used directly when it is the type of a variable, member.
+Indirect uses arise through pointers to structs.
+That is, when use of an incomplete struct would be legal, the use is indirect.
+An example is
+@samp{struct one direct; struct two * indirect;}.
+
+The optional second word limits the specification to
+ordinary structs (@samp{ord:}) or generic structs (@samp{gen:}).
+Generic structs are a bit complicated to explain.
+For C++, these are non-explicit specializations of template classes,
+or non-template classes within the above.
+Other programming languages have generics,
+but @samp{-femit-struct-debug-detailed} does not yet implement them.
+
+The third word specifies the source files for those
+structs for which the compiler will emit debug information.
+The values @samp{none} and @samp{any} have the normal meaning.
+The value @samp{base} means that
+the base of name of the file in which the type declaration appears
+must match the base of the name of the main compilation file.
+In practice, this means that
+types declared in @file{foo.c} and @file{foo.h} will have debug information,
+but types declared in other header will not.
+The value @samp{sys} means those types satisfying @samp{base}
+or declared in system or compiler headers.
+
+You may need to experiment to determine the best settings for your application.
+
+The default is @samp{-femit-struct-debug-detailed=all}.
+
+This option works only with DWARF 2.
+
+@item -fno-merge-debug-strings
+@opindex fmerge-debug-strings
+@opindex fno-merge-debug-strings
+Direct the linker to not merge together strings in the debugging
+information which are identical in different object files. Merging is
+not supported by all assemblers or linkers. Merging decreases the size
+of the debug information in the output file at the cost of increasing
+link processing time. Merging is enabled by default.
+
+@item -fdebug-prefix-map=@var{old}=@var{new}
+@opindex fdebug-prefix-map
+When compiling files in directory @file{@var{old}}, record debugging
+information describing them as in @file{@var{new}} instead.
+
+@item -fno-dwarf2-cfi-asm
+@opindex fdwarf2-cfi-asm
+@opindex fno-dwarf2-cfi-asm
+Emit DWARF 2 unwind info as compiler generated @code{.eh_frame} section
+instead of using GAS @code{.cfi_*} directives.
+
+@cindex @command{prof}
@item -p
@opindex p
Generate extra code to write profile information suitable for the
-analysis program @code{prof}. You must use this option when compiling
+analysis program @command{prof}. You must use this option when compiling
the source files you want data about, and you must also use it when
linking.
-@cindex @code{gprof}
+@cindex @command{gprof}
@item -pg
@opindex pg
Generate extra code to write profile information suitable for the
-analysis program @code{gprof}. You must use this option when compiling
+analysis program @command{gprof}. You must use this option when compiling
the source files you want data about, and you must also use it when
linking.
Makes the compiler print some statistics about permanent memory
allocation when it finishes.
+@item -fpre-ipa-mem-report
+@opindex fpre-ipa-mem-report
+@item -fpost-ipa-mem-report
+@opindex fpost-ipa-mem-report
+Makes the compiler print some statistics about permanent memory
+allocation before or after interprocedural optimization.
+
@item -fprofile-arcs
@opindex fprofile-arcs
-Instrument @dfn{arcs} during compilation to generate coverage data
-or for profile-directed block ordering. During execution the program
-records how many times each branch is executed and how many times it is
-taken. When the compiled program exits it saves this data to a file
-called @file{@var{sourcename}.da} for each source file.
-
-For profile-directed block ordering, compile the program with
-@option{-fprofile-arcs} plus optimization and code generation options,
-generate the arc profile information by running the program on a
-selected workload, and then compile the program again with the same
-optimization and code generation options plus
+Add code so that program flow @dfn{arcs} are instrumented. During
+execution the program records how many times each branch and call is
+executed and how many times it is taken or returns. When the compiled
+program exits it saves this data to a file called
+@file{@var{auxname}.gcda} for each source file. The data may be used for
+profile-directed optimizations (@option{-fbranch-probabilities}), or for
+test coverage analysis (@option{-ftest-coverage}). Each object file's
+@var{auxname} is generated from the name of the output file, if
+explicitly specified and it is not the final executable, otherwise it is
+the basename of the source file. In both cases any suffix is removed
+(e.g.@: @file{foo.gcda} for input file @file{dir/foo.c}, or
+@file{dir/foo.gcda} for output file specified as @option{-o dir/foo.o}).
+@xref{Cross-profiling}.
+
+@cindex @command{gcov}
+@item --coverage
+@opindex coverage
+
+This option is used to compile and link code instrumented for coverage
+analysis. The option is a synonym for @option{-fprofile-arcs}
+@option{-ftest-coverage} (when compiling) and @option{-lgcov} (when
+linking). See the documentation for those options for more details.
+
+@itemize
+
+@item
+Compile the source files with @option{-fprofile-arcs} plus optimization
+and code generation options. For test coverage analysis, use the
+additional @option{-ftest-coverage} option. You do not need to profile
+every source file in a program.
+
+@item
+Link your object files with @option{-lgcov} or @option{-fprofile-arcs}
+(the latter implies the former).
+
+@item
+Run the program on a representative workload to generate the arc profile
+information. This may be repeated any number of times. You can run
+concurrent instances of your program, and provided that the file system
+supports locking, the data files will be correctly updated. Also
+@code{fork} calls are detected and correctly handled (double counting
+will not happen).
+
+@item
+For profile-directed optimizations, compile the source files again with
+the same optimization and code generation options plus
@option{-fbranch-probabilities} (@pxref{Optimize Options,,Options that
Control Optimization}).
-The other use of @option{-fprofile-arcs} is for use with @code{gcov},
-when it is used with the @option{-ftest-coverage} option.
+@item
+For test coverage analysis, use @command{gcov} to produce human readable
+information from the @file{.gcno} and @file{.gcda} files. Refer to the
+@command{gcov} documentation for further information.
+
+@end itemize
With @option{-fprofile-arcs}, for each function of your program GCC
creates a program flow graph, then finds a spanning tree for the graph.
@need 2000
@item -ftest-coverage
@opindex ftest-coverage
-Create data files for the @command{gcov} code-coverage utility
-(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}).
-The data file names begin with the name of your source file:
-
-@table @gcctabopt
-@item @var{sourcename}.bb
-A mapping from basic blocks to line numbers, which @code{gcov} uses to
-associate basic block execution counts with line numbers.
-
-@item @var{sourcename}.bbg
-A list of all arcs in the program flow graph. This allows @code{gcov}
-to reconstruct the program flow graph, so that it can compute all basic
-block and arc execution counts from the information in the
-@code{@var{sourcename}.da} file.
-@end table
-
-Use @option{-ftest-coverage} with @option{-fprofile-arcs}; the latter
-option adds instrumentation to the program, which then writes
-execution counts to another data file:
-
-@table @gcctabopt
-@item @var{sourcename}.da
-Runtime arc execution counts, used in conjunction with the arc
-information in the file @code{@var{sourcename}.bbg}.
-@end table
-
-Coverage data will map better to the source files if
-@option{-ftest-coverage} is used without optimization.
+Produce a notes file that the @command{gcov} code-coverage utility
+(@pxref{Gcov,, @command{gcov}---a Test Coverage Program}) can use to
+show program coverage. Each source file's note file is called
+@file{@var{auxname}.gcno}. Refer to the @option{-fprofile-arcs} option
+above for a description of @var{auxname} and instructions on how to
+generate test coverage data. Coverage data will match the source files
+more closely, if you do not optimize.
+
+@item -fdbg-cnt-list
+@opindex fdbg-cnt-list
+Print the name and the counter upperbound for all debug counters.
+
+@item -fdbg-cnt=@var{counter-value-list}
+@opindex fdbg-cnt
+Set the internal debug counter upperbound. @var{counter-value-list}
+is a comma-separated list of @var{name}:@var{value} pairs
+which sets the upperbound of each debug counter @var{name} to @var{value}.
+All debug counters have the initial upperbound of @var{UINT_MAX},
+thus dbg_cnt() returns true always unless the upperbound is set by this option.
+e.g. With -fdbg-cnt=dce:10,tail_call:0
+dbg_cnt(dce) will return true only for first 10 invocations
+and dbg_cnt(tail_call) will return false always.
@item -d@var{letters}
+@itemx -fdump-rtl-@var{pass}
@opindex d
Says to make debugging dumps during compilation at times specified by
-@var{letters}. This is used for debugging the compiler. The file names
-for most of the dumps are made by appending a pass number and a word to
-the source file name (e.g. @file{foo.c.00.rtl} or @file{foo.c.01.sibling}).
-Here are the possible letters for use in @var{letters}, and their meanings:
+@var{letters}. This is used for debugging the RTL-based passes of the
+compiler. The file names for most of the dumps are made by appending a
+pass number and a word to the @var{dumpname}. @var{dumpname} is generated
+from the name of the output file, if explicitly specified and it is not
+an executable, otherwise it is the basename of the source file. These
+switches may have different effects when @option{-E} is used for
+preprocessing.
+
+Debug dumps can be enabled with a @option{-fdump-rtl} switch or some
+@option{-d} option @var{letters}. Here are the possible
+letters for use in @var{pass} and @var{letters}, and their meanings:
-@table @samp
-@item A
+@table @gcctabopt
+
+@item -fdump-rtl-alignments
+@opindex fdump-rtl-alignments
+Dump after branch alignments have been computed.
+
+@item -fdump-rtl-asmcons
+@opindex fdump-rtl-asmcons
+Dump after fixing rtl statements that have unsatisfied in/out constraints.
+
+@item -fdump-rtl-auto_inc_dec
+@opindex fdump-rtl-auto_inc_dec
+Dump after auto-inc-dec discovery. This pass is only run on
+architectures that have auto inc or auto dec instructions.
+
+@item -fdump-rtl-barriers
+@opindex fdump-rtl-barriers
+Dump after cleaning up the barrier instructions.
+
+@item -fdump-rtl-bbpart
+@opindex fdump-rtl-bbpart
+Dump after partitioning hot and cold basic blocks.
+
+@item -fdump-rtl-bbro
+@opindex fdump-rtl-bbro
+Dump after block reordering.
+
+@item -fdump-rtl-btl1
+@itemx -fdump-rtl-btl2
+@opindex fdump-rtl-btl2
+@opindex fdump-rtl-btl2
+@option{-fdump-rtl-btl1} and @option{-fdump-rtl-btl2} enable dumping
+after the two branch
+target load optimization passes.
+
+@item -fdump-rtl-bypass
+@opindex fdump-rtl-bypass
+Dump after jump bypassing and control flow optimizations.
+
+@item -fdump-rtl-combine
+@opindex fdump-rtl-combine
+Dump after the RTL instruction combination pass.
+
+@item -fdump-rtl-compgotos
+@opindex fdump-rtl-compgotos
+Dump after duplicating the computed gotos.
+
+@item -fdump-rtl-ce1
+@itemx -fdump-rtl-ce2
+@itemx -fdump-rtl-ce3
+@opindex fdump-rtl-ce1
+@opindex fdump-rtl-ce2
+@opindex fdump-rtl-ce3
+@option{-fdump-rtl-ce1}, @option{-fdump-rtl-ce2}, and
+@option{-fdump-rtl-ce3} enable dumping after the three
+if conversion passes.
+
+@itemx -fdump-rtl-cprop_hardreg
+@opindex fdump-rtl-cprop_hardreg
+Dump after hard register copy propagation.
+
+@itemx -fdump-rtl-csa
+@opindex fdump-rtl-csa
+Dump after combining stack adjustments.
+
+@item -fdump-rtl-cse1
+@itemx -fdump-rtl-cse2
+@opindex fdump-rtl-cse1
+@opindex fdump-rtl-cse2
+@option{-fdump-rtl-cse1} and @option{-fdump-rtl-cse2} enable dumping after
+the two common sub-expression elimination passes.
+
+@itemx -fdump-rtl-dce
+@opindex fdump-rtl-dce
+Dump after the standalone dead code elimination passes.
+
+@itemx -fdump-rtl-dbr
+@opindex fdump-rtl-dbr
+Dump after delayed branch scheduling.
+
+@item -fdump-rtl-dce1
+@itemx -fdump-rtl-dce2
+@opindex fdump-rtl-dce1
+@opindex fdump-rtl-dce2
+@option{-fdump-rtl-dce1} and @option{-fdump-rtl-dce2} enable dumping after
+the two dead store elimination passes.
+
+@item -fdump-rtl-eh
+@opindex fdump-rtl-eh
+Dump after finalization of EH handling code.
+
+@item -fdump-rtl-eh_ranges
+@opindex fdump-rtl-eh_ranges
+Dump after conversion of EH handling range regions.
+
+@item -fdump-rtl-expand
+@opindex fdump-rtl-expand
+Dump after RTL generation.
+
+@item -fdump-rtl-fwprop1
+@itemx -fdump-rtl-fwprop2
+@opindex fdump-rtl-fwprop1
+@opindex fdump-rtl-fwprop2
+@option{-fdump-rtl-fwprop1} and @option{-fdump-rtl-fwprop2} enable
+dumping after the two forward propagation passes.
+
+@item -fdump-rtl-gcse1
+@itemx -fdump-rtl-gcse2
+@opindex fdump-rtl-gcse1
+@opindex fdump-rtl-gcse2
+@option{-fdump-rtl-gcse1} and @option{-fdump-rtl-gcse2} enable dumping
+after global common subexpression elimination.
+
+@item -fdump-rtl-init-regs
+@opindex fdump-rtl-init-regs
+Dump after the initialization of the registers.
+
+@item -fdump-rtl-initvals
+@opindex fdump-rtl-initvals
+Dump after the computation of the initial value sets.
+
+@itemx -fdump-rtl-into_cfglayout
+@opindex fdump-rtl-into_cfglayout
+Dump after converting to cfglayout mode.
+
+@item -fdump-rtl-ira
+@opindex fdump-rtl-ira
+Dump after iterated register allocation.
+
+@item -fdump-rtl-jump
+@opindex fdump-rtl-jump
+Dump after the second jump optimization.
+
+@item -fdump-rtl-loop2
+@opindex fdump-rtl-loop2
+@option{-fdump-rtl-loop2} enables dumping after the rtl
+loop optimization passes.
+
+@item -fdump-rtl-mach
+@opindex fdump-rtl-mach
+Dump after performing the machine dependent reorganization pass, if that
+pass exists.
+
+@item -fdump-rtl-mode_sw
+@opindex fdump-rtl-mode_sw
+Dump after removing redundant mode switches.
+
+@item -fdump-rtl-rnreg
+@opindex fdump-rtl-rnreg
+Dump after register renumbering.
+
+@itemx -fdump-rtl-outof_cfglayout
+@opindex fdump-rtl-outof_cfglayout
+Dump after converting from cfglayout mode.
+
+@item -fdump-rtl-peephole2
+@opindex fdump-rtl-peephole2
+Dump after the peephole pass.
+
+@item -fdump-rtl-postreload
+@opindex fdump-rtl-postreload
+Dump after post-reload optimizations.
+
+@itemx -fdump-rtl-pro_and_epilogue
+@opindex fdump-rtl-pro_and_epilogue
+Dump after generating the function pro and epilogues.
+
+@item -fdump-rtl-regmove
+@opindex fdump-rtl-regmove
+Dump after the register move pass.
+
+@item -fdump-rtl-sched1
+@itemx -fdump-rtl-sched2
+@opindex fdump-rtl-sched1
+@opindex fdump-rtl-sched2
+@option{-fdump-rtl-sched1} and @option{-fdump-rtl-sched2} enable dumping
+after the basic block scheduling passes.
+
+@item -fdump-rtl-see
+@opindex fdump-rtl-see
+Dump after sign extension elimination.
+
+@item -fdump-rtl-seqabstr
+@opindex fdump-rtl-seqabstr
+Dump after common sequence discovery.
+
+@item -fdump-rtl-shorten
+@opindex fdump-rtl-shorten
+Dump after shortening branches.
+
+@item -fdump-rtl-sibling
+@opindex fdump-rtl-sibling
+Dump after sibling call optimizations.
+
+@item -fdump-rtl-split1
+@itemx -fdump-rtl-split2
+@itemx -fdump-rtl-split3
+@itemx -fdump-rtl-split4
+@itemx -fdump-rtl-split5
+@opindex fdump-rtl-split1
+@opindex fdump-rtl-split2
+@opindex fdump-rtl-split3
+@opindex fdump-rtl-split4
+@opindex fdump-rtl-split5
+@option{-fdump-rtl-split1}, @option{-fdump-rtl-split2},
+@option{-fdump-rtl-split3}, @option{-fdump-rtl-split4} and
+@option{-fdump-rtl-split5} enable dumping after five rounds of
+instruction splitting.
+
+@item -fdump-rtl-sms
+@opindex fdump-rtl-sms
+Dump after modulo scheduling. This pass is only run on some
+architectures.
+
+@item -fdump-rtl-stack
+@opindex fdump-rtl-stack
+Dump after conversion from GCC's "flat register file" registers to the
+x87's stack-like registers. This pass is only run on x86 variants.
+
+@item -fdump-rtl-subreg1
+@itemx -fdump-rtl-subreg2
+@opindex fdump-rtl-subreg1
+@opindex fdump-rtl-subreg2
+@option{-fdump-rtl-subreg1} and @option{-fdump-rtl-subreg2} enable dumping after
+the two subreg expansion passes.
+
+@item -fdump-rtl-unshare
+@opindex fdump-rtl-unshare
+Dump after all rtl has been unshared.
+
+@item -fdump-rtl-vartrack
+@opindex fdump-rtl-vartrack
+Dump after variable tracking.
+
+@item -fdump-rtl-vregs
+@opindex fdump-rtl-vregs
+Dump after converting virtual registers to hard registers.
+
+@item -fdump-rtl-web
+@opindex fdump-rtl-web
+Dump after live range splitting.
+
+@item -fdump-rtl-regclass
+@itemx -fdump-rtl-subregs_of_mode_init
+@itemx -fdump-rtl-subregs_of_mode_finish
+@itemx -fdump-rtl-dfinit
+@itemx -fdump-rtl-dfinish
+@opindex fdump-rtl-regclass
+@opindex fdump-rtl-subregs_of_mode_init
+@opindex fdump-rtl-subregs_of_mode_finish
+@opindex fdump-rtl-dfinit
+@opindex fdump-rtl-dfinish
+These dumps are defined but always produce empty files.
+
+@item -fdump-rtl-all
+@opindex fdump-rtl-all
+Produce all the dumps listed above.
+
+@item -dA
@opindex dA
Annotate the assembler output with miscellaneous debugging information.
-@item b
-@opindex db
-Dump after computing branch probabilities, to @file{@var{file}.14.bp}.
-@item B
-@opindex dB
-Dump after block reordering, to @file{@var{file}.29.bbro}.
-@item c
-@opindex dc
-Dump after instruction combination, to the file @file{@var{file}.16.combine}.
-@item C
-@opindex dC
-Dump after the first if conversion, to the file @file{@var{file}.17.ce}.
-@item d
-@opindex dd
-Dump after delayed branch scheduling, to @file{@var{file}.31.dbr}.
-@item D
+
+@item -dD
@opindex dD
Dump all macro definitions, at the end of preprocessing, in addition to
normal output.
-@item e
-@opindex de
-Dump after SSA optimizations, to @file{@var{file}.04.ssa} and
-@file{@var{file}.07.ussa}.
-@item E
-@opindex dE
-Dump after the second if conversion, to @file{@var{file}.26.ce2}.
-@item f
-@opindex df
-Dump after life analysis, to @file{@var{file}.15.life}.
-@item F
-@opindex dF
-Dump after purging @code{ADDRESSOF} codes, to @file{@var{file}.09.addressof}.
-@item g
-@opindex dg
-Dump after global register allocation, to @file{@var{file}.21.greg}.
-@item h
-@opindex dh
-Dump after finalization of EH handling code, to @file{@var{file}.02.eh}.
-@item k
-@opindex dk
-Dump after reg-to-stack conversion, to @file{@var{file}.28.stack}.
-@item o
-@opindex do
-Dump after post-reload optimizations, to @file{@var{file}.22.postreload}.
-@item G
-@opindex dG
-Dump after GCSE, to @file{@var{file}.10.gcse}.
-@item i
-@opindex di
-Dump after sibling call optimizations, to @file{@var{file}.01.sibling}.
-@item j
-@opindex dj
-Dump after the first jump optimization, to @file{@var{file}.03.jump}.
-@item k
-@opindex dk
-Dump after conversion from registers to stack, to @file{@var{file}.32.stack}.
-@item l
-@opindex dl
-Dump after local register allocation, to @file{@var{file}.20.lreg}.
-@item L
-@opindex dL
-Dump after loop optimization, to @file{@var{file}.11.loop}.
-@item M
-@opindex dM
-Dump after performing the machine dependent reorganisation pass, to
-@file{@var{file}.30.mach}.
-@item n
-@opindex dn
-Dump after register renumbering, to @file{@var{file}.25.rnreg}.
-@item N
-@opindex dN
-Dump after the register move pass, to @file{@var{file}.18.regmove}.
-@item r
-@opindex dr
-Dump after RTL generation, to @file{@var{file}.00.rtl}.
-@item R
-@opindex dR
-Dump after the second scheduling pass, to @file{@var{file}.27.sched2}.
-@item s
-@opindex ds
-Dump after CSE (including the jump optimization that sometimes follows
-CSE), to @file{@var{file}.08.cse}.
-@item S
-@opindex dS
-Dump after the first scheduling pass, to @file{@var{file}.19.sched}.
-@item t
-@opindex dt
-Dump after the second CSE pass (including the jump optimization that
-sometimes follows CSE), to @file{@var{file}.12.cse2}.
-@item w
-@opindex dw
-Dump after the second flow pass, to @file{@var{file}.23.flow2}.
-@item X
-@opindex dX
-Dump after SSA dead code elimination, to @file{@var{file}.06.ssadce}.
-@item z
-@opindex dz
-Dump after the peephole pass, to @file{@var{file}.24.peephole2}.
-@item a
-@opindex da
-Produce all the dumps listed above.
-@item m
+
+@item -dH
+@opindex dH
+Produce a core dump whenever an error occurs.
+
+@item -dm
@opindex dm
Print statistics on memory usage, at the end of the run, to
standard error.
-@item p
+
+@item -dp
@opindex dp
Annotate the assembler output with a comment indicating which
pattern and alternative was used. The length of each instruction is
also printed.
-@item P
+
+@item -dP
@opindex dP
Dump the RTL in the assembler output as a comment before each instruction.
Also turns on @option{-dp} annotation.
-@item v
+
+@item -dv
@opindex dv
-For each of the other indicated dump files (except for
-@file{@var{file}.00.rtl}), dump a representation of the control flow graph
-suitable for viewing with VCG to @file{@var{file}.@var{pass}.vcg}.
-@item x
+For each of the other indicated dump files (@option{-fdump-rtl-@var{pass}}),
+dump a representation of the control flow graph suitable for viewing with VCG
+to @file{@var{file}.@var{pass}.vcg}.
+
+@item -dx
@opindex dx
Just generate RTL for a function instead of compiling it. Usually used
-with @samp{r}.
-@item y
+with @option{-fdump-rtl-expand}.
+
+@item -dy
@opindex dy
Dump debugging information during parsing, to standard error.
@end table
+@item -fdump-noaddr
+@opindex fdump-noaddr
+When doing debugging dumps, suppress address output. This makes it more
+feasible to use diff on debugging dumps for compiler invocations with
+different compiler binaries and/or different
+text / bss / data / heap / stack / dso start locations.
+
@item -fdump-unnumbered
@opindex fdump-unnumbered
-When doing debugging dumps (see @option{-d} option above), suppress instruction
-numbers and line number note output. This makes it more feasible to
-use diff on debugging dumps for compiler invocations with different
-options, in particular with and without @option{-g}.
+When doing debugging dumps, suppress instruction numbers and address output.
+This makes it more feasible to use diff on debugging dumps for compiler
+invocations with different options, in particular with and without
+@option{-g}.
-@item -fdump-translation-unit @r{(C and C++ only)}
-@itemx -fdump-translation-unit-@var{options} @r{(C and C++ only)}
+@item -fdump-translation-unit @r{(C++ only)}
+@itemx -fdump-translation-unit-@var{options} @r{(C++ only)}
@opindex fdump-translation-unit
Dump a representation of the tree structure for the entire translation
unit to a file. The file name is made by appending @file{.tu} to the
@var{options} controls the details of the dump as described for the
@option{-fdump-tree} options.
-@item -fdump-tree-@var{switch} @r{(C++ only)}
-@itemx -fdump-tree-@var{switch}-@var{options} @r{(C++ only)}
+@item -fdump-ipa-@var{switch}
+@opindex fdump-ipa
+Control the dumping at various stages of inter-procedural analysis
+language tree to a file. The file name is generated by appending a switch
+specific suffix to the source file name. The following dumps are possible:
+
+@table @samp
+@item all
+Enables all inter-procedural analysis dumps.
+
+@item cgraph
+Dumps information about call-graph optimization, unused function removal,
+and inlining decisions.
+
+@item inline
+Dump after function inlining.
+
+@end table
+
+@item -fdump-statistics-@var{option}
+@opindex -fdump-statistics
+Enable and control dumping of pass statistics in a separate file. The
+file name is generated by appending a suffix ending in @samp{.statistics}
+to the source file name. If the @samp{-@var{option}} form is used,
+@samp{-stats} will cause counters to be summed over the whole compilation unit
+while @samp{-details} will dump every event as the passes generate them.
+The default with no option is to sum counters for each function compiled.
+
+@item -fdump-tree-@var{switch}
+@itemx -fdump-tree-@var{switch}-@var{options}
@opindex fdump-tree
Control the dumping at various stages of processing the intermediate
language tree to a file. The file name is generated by appending a switch
specific suffix to the source file name. If the @samp{-@var{options}}
form is used, @var{options} is a list of @samp{-} separated options that
-control the details of the dump. Not all options are applicable to all
-dumps, those which are not meaningful will be ignored. The following
+control the details of the dump. Not all options are applicable to all
+dumps, those which are not meaningful will be ignored. The following
options are available
@table @samp
@item address
Print the address of each node. Usually this is not meaningful as it
-changes according to the environment and source file. Its primary use
+changes according to the environment and source file. Its primary use
is for tying up a dump file with a debug environment.
@item slim
Inhibit dumping of members of a scope or body of a function merely
-because that scope has been reached. Only dump such items when they
-are directly reachable by some other path.
+because that scope has been reached. Only dump such items when they
+are directly reachable by some other path. When dumping pretty-printed
+trees, this option inhibits dumping the bodies of control structures.
+@item raw
+Print a raw representation of the tree. By default, trees are
+pretty-printed into a C-like representation.
+@item details
+Enable more detailed dumps (not honored by every dump option).
+@item stats
+Enable dumping various statistics about the pass (not honored by every dump
+option).
+@item blocks
+Enable showing basic block boundaries (disabled in raw dumps).
+@item vops
+Enable showing virtual operands for every statement.
+@item lineno
+Enable showing line numbers for statements.
+@item uid
+Enable showing the unique ID (@code{DECL_UID}) for each variable.
+@item verbose
+Enable showing the tree dump for each statement.
@item all
-Turn on all options.
+Turn on all options, except @option{raw}, @option{slim}, @option{verbose}
+and @option{lineno}.
@end table
The following tree dumps are possible:
@table @samp
+
@item original
Dump before any tree based optimization, to @file{@var{file}.original}.
+
@item optimized
Dump after all tree based optimization, to @file{@var{file}.optimized}.
-@item inlined
-Dump after function inlining, to @file{@var{file}.inlined}.
+
+@item gimple
+@opindex fdump-tree-gimple
+Dump each function before and after the gimplification pass to a file. The
+file name is made by appending @file{.gimple} to the source file name.
+
+@item cfg
+@opindex fdump-tree-cfg
+Dump the control flow graph of each function to a file. The file name is
+made by appending @file{.cfg} to the source file name.
+
+@item vcg
+@opindex fdump-tree-vcg
+Dump the control flow graph of each function to a file in VCG format. The
+file name is made by appending @file{.vcg} to the source file name. Note
+that if the file contains more than one function, the generated file cannot
+be used directly by VCG@. You will need to cut and paste each function's
+graph into its own separate file first.
+
+@item ch
+@opindex fdump-tree-ch
+Dump each function after copying loop headers. The file name is made by
+appending @file{.ch} to the source file name.
+
+@item ssa
+@opindex fdump-tree-ssa
+Dump SSA related information to a file. The file name is made by appending
+@file{.ssa} to the source file name.
+
+@item alias
+@opindex fdump-tree-alias
+Dump aliasing information for each function. The file name is made by
+appending @file{.alias} to the source file name.
+
+@item ccp
+@opindex fdump-tree-ccp
+Dump each function after CCP@. The file name is made by appending
+@file{.ccp} to the source file name.
+
+@item storeccp
+@opindex fdump-tree-storeccp
+Dump each function after STORE-CCP@. The file name is made by appending
+@file{.storeccp} to the source file name.
+
+@item pre
+@opindex fdump-tree-pre
+Dump trees after partial redundancy elimination. The file name is made
+by appending @file{.pre} to the source file name.
+
+@item fre
+@opindex fdump-tree-fre
+Dump trees after full redundancy elimination. The file name is made
+by appending @file{.fre} to the source file name.
+
+@item copyprop
+@opindex fdump-tree-copyprop
+Dump trees after copy propagation. The file name is made
+by appending @file{.copyprop} to the source file name.
+
+@item store_copyprop
+@opindex fdump-tree-store_copyprop
+Dump trees after store copy-propagation. The file name is made
+by appending @file{.store_copyprop} to the source file name.
+
+@item dce
+@opindex fdump-tree-dce
+Dump each function after dead code elimination. The file name is made by
+appending @file{.dce} to the source file name.
+
+@item mudflap
+@opindex fdump-tree-mudflap
+Dump each function after adding mudflap instrumentation. The file name is
+made by appending @file{.mudflap} to the source file name.
+
+@item sra
+@opindex fdump-tree-sra
+Dump each function after performing scalar replacement of aggregates. The
+file name is made by appending @file{.sra} to the source file name.
+
+@item sink
+@opindex fdump-tree-sink
+Dump each function after performing code sinking. The file name is made
+by appending @file{.sink} to the source file name.
+
+@item dom
+@opindex fdump-tree-dom
+Dump each function after applying dominator tree optimizations. The file
+name is made by appending @file{.dom} to the source file name.
+
+@item dse
+@opindex fdump-tree-dse
+Dump each function after applying dead store elimination. The file
+name is made by appending @file{.dse} to the source file name.
+
+@item phiopt
+@opindex fdump-tree-phiopt
+Dump each function after optimizing PHI nodes into straightline code. The file
+name is made by appending @file{.phiopt} to the source file name.
+
+@item forwprop
+@opindex fdump-tree-forwprop
+Dump each function after forward propagating single use variables. The file
+name is made by appending @file{.forwprop} to the source file name.
+
+@item copyrename
+@opindex fdump-tree-copyrename
+Dump each function after applying the copy rename optimization. The file
+name is made by appending @file{.copyrename} to the source file name.
+
+@item nrv
+@opindex fdump-tree-nrv
+Dump each function after applying the named return value optimization on
+generic trees. The file name is made by appending @file{.nrv} to the source
+file name.
+
+@item vect
+@opindex fdump-tree-vect
+Dump each function after applying vectorization of loops. The file name is
+made by appending @file{.vect} to the source file name.
+
+@item vrp
+@opindex fdump-tree-vrp
+Dump each function after Value Range Propagation (VRP). The file name
+is made by appending @file{.vrp} to the source file name.
+
+@item all
+@opindex fdump-tree-all
+Enable all the available tree dumps with the flags provided in this option.
@end table
+@item -ftree-vectorizer-verbose=@var{n}
+@opindex ftree-vectorizer-verbose
+This option controls the amount of debugging output the vectorizer prints.
+This information is written to standard error, unless
+@option{-fdump-tree-all} or @option{-fdump-tree-vect} is specified,
+in which case it is output to the usual dump listing file, @file{.vect}.
+For @var{n}=0 no diagnostic information is reported.
+If @var{n}=1 the vectorizer reports each loop that got vectorized,
+and the total number of loops that got vectorized.
+If @var{n}=2 the vectorizer also reports non-vectorized loops that passed
+the first analysis phase (vect_analyze_loop_form) - i.e.@: countable,
+inner-most, single-bb, single-entry/exit loops. This is the same verbosity
+level that @option{-fdump-tree-vect-stats} uses.
+Higher verbosity levels mean either more information dumped for each
+reported loop, or same amount of information reported for more loops:
+If @var{n}=3, alignment related information is added to the reports.
+If @var{n}=4, data-references related information (e.g.@: memory dependences,
+memory access-patterns) is added to the reports.
+If @var{n}=5, the vectorizer reports also non-vectorized inner-most loops
+that did not pass the first analysis phase (i.e., may not be countable, or
+may have complicated control-flow).
+If @var{n}=6, the vectorizer reports also non-vectorized nested loops.
+For @var{n}=7, all the information the vectorizer generates during its
+analysis and transformation is reported. This is the same verbosity level
+that @option{-fdump-tree-vect-details} uses.
+
+@item -frandom-seed=@var{string}
+@opindex frandom-string
+This option provides a seed that GCC uses when it would otherwise use
+random numbers. It is used to generate certain symbol names
+that have to be different in every compiled file. It is also used to
+place unique stamps in coverage data files and the object files that
+produce them. You can use the @option{-frandom-seed} option to produce
+reproducibly identical object files.
+
+The @var{string} should be different for every file you compile.
+
@item -fsched-verbose=@var{n}
@opindex fsched-verbose
On targets that use instruction scheduling, this option controls the
amount of debugging output the scheduler prints. This information is
-written to standard error, unless @option{-dS} or @option{-dR} is
-specified, in which case it is output to the usual dump
-listing file, @file{.sched} or @file{.sched2} respectively. However
-for @var{n} greater than nine, the output is always printed to standard
-error.
+written to standard error, unless @option{-fdump-rtl-sched1} or
+@option{-fdump-rtl-sched2} is specified, in which case it is output
+to the usual dump listing file, @file{.sched} or @file{.sched2}
+respectively. However for @var{n} greater than nine, the output is
+always printed to standard error.
For @var{n} greater than zero, @option{-fsched-verbose} outputs the
-same information as @option{-dRS}. For @var{n} greater than one, it
-also output basic block probabilities, detailed ready list information
-and unit/insn info. For @var{n} greater than two, it includes RTL
-at abort point, control-flow and regions info. And for @var{n} over
-four, @option{-fsched-verbose} also includes dependence info.
-
-@item -fpretend-float
-@opindex fpretend-float
-When running a cross-compiler, pretend that the target machine uses the
-same floating point format as the host machine. This causes incorrect
-output of the actual floating constants, but the actual instruction
-sequence will probably be the same as GCC would make when running on
-the target machine.
+same information as @option{-fdump-rtl-sched1} and @option{-fdump-rtl-sched2}.
+For @var{n} greater than one, it also output basic block probabilities,
+detailed ready list information and unit/insn info. For @var{n} greater
+than two, it includes RTL at abort point, control-flow and regions info.
+And for @var{n} over four, @option{-fsched-verbose} also includes
+dependence info.
@item -save-temps
@opindex save-temps
preprocessed @file{foo.i} output file even though the compiler now
normally uses an integrated preprocessor.
+When used in combination with the @option{-x} command line option,
+@option{-save-temps} is sensible enough to avoid over writing an
+input source file with the same extension as an intermediate file.
+The corresponding intermediate file may be obtained by renaming the
+source file before using @option{-save-temps}.
+
@item -time
@opindex time
Report the CPU time taken by each subprocess in the compilation
# as 0.00 0.01
@end smallexample
-The first number on each line is the ``user time,'' that is time spent
-executing the program itself. The second number is ``system time,''
+The first number on each line is the ``user time'', that is time spent
+executing the program itself. The second number is ``system time'',
time spent executing operating system routines on behalf of the program.
Both numbers are in seconds.
+@item -fvar-tracking
+@opindex fvar-tracking
+Run variable tracking pass. It computes where variables are stored at each
+position in code. Better debugging information is then generated
+(if the debugging information format supports this information).
+
+It is enabled by default when compiling with optimization (@option{-Os},
+@option{-O}, @option{-O2}, @dots{}), debugging information (@option{-g}) and
+the debug info format supports it.
+
@item -print-file-name=@var{library}
@opindex print-file-name
Print the full absolute name of the library file @var{library} that
This is useful when you use @option{-nostdlib} or @option{-nodefaultlibs}
but you do want to link with @file{libgcc.a}. You can do
-@example
+@smallexample
gcc -nostdlib @var{files}@dots{} `gcc -print-libgcc-file-name`
-@end example
+@end smallexample
@item -print-search-dirs
@opindex print-search-dirs
Print the name of the configured installation directory and a list of
-program and library directories gcc will search---and don't do anything else.
+program and library directories @command{gcc} will search---and don't do anything else.
-This is useful when gcc prints the error message
+This is useful when @command{gcc} prints the error message
@samp{installation problem, cannot exec cpp0: No such file or directory}.
To resolve this you either need to put @file{cpp0} and the other compiler
-components where gcc expects to find them, or you can set the environment
+components where @command{gcc} expects to find them, or you can set the environment
variable @env{GCC_EXEC_PREFIX} to the directory where you installed them.
-Don't forget the trailing '/'.
+Don't forget the trailing @samp{/}.
@xref{Environment Variables}.
+@item -print-sysroot
+@opindex print-sysroot
+Print the target sysroot directory that will be used during
+compilation. This is the target sysroot specified either at configure
+time or using the @option{--sysroot} option, possibly with an extra
+suffix that depends on compilation options. If no target sysroot is
+specified, the option prints nothing.
+
+@item -print-sysroot-headers-suffix
+@opindex print-sysroot-headers-suffix
+Print the suffix added to the target sysroot when searching for
+headers, or give an error if the compiler is not configured with such
+a suffix---and don't do anything else.
+
@item -dumpmachine
@opindex dumpmachine
Print the compiler's target machine (for example,
@opindex dumpspecs
Print the compiler's built-in specs---and don't do anything else. (This
is used when GCC itself is being built.) @xref{Spec Files}.
+
+@item -feliminate-unused-debug-types
+@opindex feliminate-unused-debug-types
+Normally, when producing DWARF2 output, GCC will emit debugging
+information for all types declared in a compilation
+unit, regardless of whether or not they are actually used
+in that compilation unit. Sometimes this is useful, such as
+if, in the debugger, you want to cast a value to a type that is
+not actually used in your program (but is declared). More often,
+however, this results in a significant amount of wasted space.
+With this option, GCC will avoid producing debug symbol output
+for types that are nowhere used in the source file being compiled.
@end table
@node Optimize Options
@cindex optimize options
@cindex options, optimization
-These options control various sorts of optimizations:
+These options control various sorts of optimizations.
+
+Without any optimization option, the compiler's goal is to reduce the
+cost of compilation and to make debugging produce the expected
+results. Statements are independent: if you stop the program with a
+breakpoint between statements, you can then assign a new value to any
+variable or change the program counter to any other statement in the
+function and get exactly the results you would expect from the source
+code.
+
+Turning on optimization flags makes the compiler attempt to improve
+the performance and/or code size at the expense of compilation time
+and possibly the ability to debug the program.
+
+The compiler performs optimization based on the knowledge it has of the
+program. Compiling multiple files at once to a single output file mode allows
+the compiler to use information gained from all of the files when compiling
+each of them.
+
+Not all optimizations are controlled directly by a flag. Only
+optimizations that have a flag are listed.
@table @gcctabopt
@item -O
Optimize. Optimizing compilation takes somewhat more time, and a lot
more memory for a large function.
-Without @option{-O}, the compiler's goal is to reduce the cost of
-compilation and to make debugging produce the expected results.
-Statements are independent: if you stop the program with a breakpoint
-between statements, you can then assign a new value to any variable or
-change the program counter to any other statement in the function and
-get exactly the results you would expect from the source code.
-
With @option{-O}, the compiler tries to reduce code size and execution
time, without performing any optimizations that take a great deal of
compilation time.
+@option{-O} turns on the following optimization flags:
+@gccoptlist{
+-fauto-inc-dec @gol
+-fcprop-registers @gol
+-fdce @gol
+-fdefer-pop @gol
+-fdelayed-branch @gol
+-fdse @gol
+-fguess-branch-probability @gol
+-fif-conversion2 @gol
+-fif-conversion @gol
+-finline-small-functions @gol
+-fipa-pure-const @gol
+-fipa-reference @gol
+-fmerge-constants
+-fsplit-wide-types @gol
+-ftree-builtin-call-dce @gol
+-ftree-ccp @gol
+-ftree-ch @gol
+-ftree-copyrename @gol
+-ftree-dce @gol
+-ftree-dominator-opts @gol
+-ftree-dse @gol
+-ftree-fre @gol
+-ftree-sra @gol
+-ftree-ter @gol
+-funit-at-a-time}
+
+@option{-O} also turns on @option{-fomit-frame-pointer} on machines
+where doing so does not interfere with debugging.
+
@item -O2
@opindex O2
Optimize even more. GCC performs nearly all supported optimizations
-that do not involve a space-speed tradeoff. The compiler does not
-perform loop unrolling or function inlining when you specify @option{-O2}.
+that do not involve a space-speed tradeoff.
As compared to @option{-O}, this option increases both compilation time
and the performance of the generated code.
-@option{-O2} turns on all optional optimizations except for loop unrolling,
-function inlining, and register renaming. It also turns on the
-@option{-fforce-mem} option on all machines and frame pointer elimination
-on machines where doing so does not interfere with debugging.
+@option{-O2} turns on all optimization flags specified by @option{-O}. It
+also turns on the following optimization flags:
+@gccoptlist{-fthread-jumps @gol
+-falign-functions -falign-jumps @gol
+-falign-loops -falign-labels @gol
+-fcaller-saves @gol
+-fcrossjumping @gol
+-fcse-follow-jumps -fcse-skip-blocks @gol
+-fdelete-null-pointer-checks @gol
+-fexpensive-optimizations @gol
+-fgcse -fgcse-lm @gol
+-findirect-inlining @gol
+-foptimize-sibling-calls @gol
+-fpeephole2 @gol
+-fregmove @gol
+-freorder-blocks -freorder-functions @gol
+-frerun-cse-after-loop @gol
+-fsched-interblock -fsched-spec @gol
+-fschedule-insns -fschedule-insns2 @gol
+-fstrict-aliasing -fstrict-overflow @gol
+-ftree-switch-conversion @gol
+-ftree-pre @gol
+-ftree-vrp}
Please note the warning under @option{-fgcse} about
invoking @option{-O2} on programs that use computed gotos.
@item -O3
@opindex O3
-Optimize yet more. @option{-O3} turns on all optimizations specified by
-@option{-O2} and also turns on the @option{-finline-functions} and
-@option{-frename-registers} options.
+Optimize yet more. @option{-O3} turns on all optimizations specified
+by @option{-O2} and also turns on the @option{-finline-functions},
+@option{-funswitch-loops}, @option{-fpredictive-commoning},
+@option{-fgcse-after-reload} and @option{-ftree-vectorize} options.
@item -O0
@opindex O0
-Do not optimize.
+Reduce compilation time and make debugging produce the expected
+results. This is the default.
@item -Os
@opindex Os
do not typically increase code size. It also performs further
optimizations designed to reduce code size.
+@option{-Os} disables the following optimization flags:
+@gccoptlist{-falign-functions -falign-jumps -falign-loops @gol
+-falign-labels -freorder-blocks -freorder-blocks-and-partition @gol
+-fprefetch-loop-arrays -ftree-vect-loop-version}
+
If you use multiple @option{-O} options, with or without level numbers,
the last such option is the one that is effective.
@end table
Options of the form @option{-f@var{flag}} specify machine-independent
flags. Most flags have both positive and negative forms; the negative
-form of @option{-ffoo} would be @option{-fno-foo}. In the table below,
-only one of the forms is listed---the one which is not the default.
-You can figure out the other form by either removing @samp{no-} or
-adding it.
-
-@table @gcctabopt
-@item -ffloat-store
-@opindex ffloat-store
-Do not store floating point variables in registers, and inhibit other
-options that might change whether a floating point value is taken from a
-register or memory.
+form of @option{-ffoo} would be @option{-fno-foo}. In the table
+below, only one of the forms is listed---the one you typically will
+use. You can figure out the other form by either removing @samp{no-}
+or adding it.
-@cindex floating point precision
-This option prevents undesirable excess precision on machines such as
-the 68000 where the floating registers (of the 68881) keep more
-precision than a @code{double} is supposed to have. Similarly for the
-x86 architecture. For most programs, the excess precision does only
-good, but a few programs rely on the precise definition of IEEE floating
-point. Use @option{-ffloat-store} for such programs, after modifying
-them to store all pertinent intermediate computations into variables.
+The following options control specific optimizations. They are either
+activated by @option{-O} options or are related to ones that are. You
+can use the following flags in the rare cases when ``fine-tuning'' of
+optimizations to be performed is desired.
+@table @gcctabopt
@item -fno-default-inline
@opindex fno-default-inline
Do not make member functions inline by default merely because they are
the compiler normally lets arguments accumulate on the stack for several
function calls and pops them all at once.
-@item -fforce-mem
-@opindex fforce-mem
-Force memory operands to be copied into registers before doing
-arithmetic on them. This produces better code by making all memory
-references potential common subexpressions. When they are not common
-subexpressions, instruction combination should eliminate the separate
-register-load. The @option{-O2} option turns on this option.
+Disabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fforward-propagate
+@opindex fforward-propagate
+Perform a forward propagation pass on RTL@. The pass tries to combine two
+instructions and checks if the result can be simplified. If loop unrolling
+is active, two passes are performed and the second is scheduled after
+loop unrolling.
-@item -fforce-addr
-@opindex fforce-addr
-Force memory address constants to be copied into registers before
-doing arithmetic on them. This may produce better code just as
-@option{-fforce-mem} may.
+This option is enabled by default at optimization levels @option{-O2},
+@option{-O3}, @option{-Os}.
@item -fomit-frame-pointer
@opindex fomit-frame-pointer
whether a target machine supports this flag. @xref{Registers,,Register
Usage, gccint, GNU Compiler Collection (GCC) Internals}.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -foptimize-sibling-calls
@opindex foptimize-sibling-calls
Optimize sibling and tail recursive calls.
-@item -ftrapv
-@opindex ftrapv
-This option generates traps for signed overflow on addition, subtraction,
-multiplication operations.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
@item -fno-inline
@opindex fno-inline
is used to keep the compiler from expanding any functions inline.
Note that if you are not optimizing, no functions can be expanded inline.
+@item -finline-small-functions
+@opindex finline-small-functions
+Integrate functions into their callers when their body is smaller than expected
+function call code (so overall size of program gets smaller). The compiler
+heuristically decides which functions are simple enough to be worth integrating
+in this way.
+
+Enabled at level @option{-O2}.
+
+@item -findirect-inlining
+@opindex findirect-inlining
+Inline also indirect calls that are discovered to be known at compile
+time thanks to previous inlining. This option has any effect only
+when inlining itself is turned on by the @option{-finline-functions}
+or @option{-finline-small-functions} options.
+
+Enabled at level @option{-O2}.
+
@item -finline-functions
@opindex finline-functions
Integrate all simple functions into their callers. The compiler
declared @code{static}, then the function is normally not output as
assembler code in its own right.
+Enabled at level @option{-O3}.
+
+@item -finline-functions-called-once
+@opindex finline-functions-called-once
+Consider all @code{static} functions called once for inlining into their
+caller even if they are not marked @code{inline}. If a call to a given
+function is integrated, then the function is not output as assembler code
+in its own right.
+
+Enabled at levels @option{-O1}, @option{-O2}, @option{-O3} and @option{-Os}.
+
+@item -fearly-inlining
+@opindex fearly-inlining
+Inline functions marked by @code{always_inline} and functions whose body seems
+smaller than the function call overhead early before doing
+@option{-fprofile-generate} instrumentation and real inlining pass. Doing so
+makes profiling significantly cheaper and usually inlining faster on programs
+having large chains of nested wrapper functions.
+
+Enabled by default.
+
@item -finline-limit=@var{n}
@opindex finline-limit
-By default, gcc limits the size of functions that can be inlined. This flag
-allows the control of this limit for functions that are explicitly marked as
-inline (ie marked with the inline keyword or defined within the class
-definition in c++). @var{n} is the size of functions that can be inlined in
-number of pseudo instructions (not counting parameter handling). The default
-value of @var{n} is 600.
-Increasing this value can result in more inlined code at
-the cost of compilation time and memory consumption. Decreasing usually makes
-the compilation faster and less code will be inlined (which presumably
-means slower programs). This option is particularly useful for programs that
-use inlining heavily such as those based on recursive templates with C++.
+By default, GCC limits the size of functions that can be inlined. This flag
+allows coarse control of this limit. @var{n} is the size of functions that
+can be inlined in number of pseudo instructions.
+
+Inlining is actually controlled by a number of parameters, which may be
+specified individually by using @option{--param @var{name}=@var{value}}.
+The @option{-finline-limit=@var{n}} option sets some of these parameters
+as follows:
+
+@table @gcctabopt
+@item max-inline-insns-single
+is set to @var{n}/2.
+@item max-inline-insns-auto
+is set to @var{n}/2.
+@end table
+
+See below for a documentation of the individual
+parameters controlling inlining and for the defaults of these parameters.
+
+@emph{Note:} there may be no value to @option{-finline-limit} that results
+in default behavior.
@emph{Note:} pseudo instruction represents, in this particular context, an
-abstract measurement of function's size. In no way, it represents a count
+abstract measurement of function's size. In no way does it represent a count
of assembly instructions and as such its exact meaning might change from one
release to an another.
@item -fkeep-inline-functions
@opindex fkeep-inline-functions
-Even if all calls to a given function are integrated, and the function
-is declared @code{static}, nevertheless output a separate run-time
-callable version of the function. This switch does not affect
-@code{extern inline} functions.
+In C, emit @code{static} functions that are declared @code{inline}
+into the object file, even if the function has been inlined into all
+of its callers. This switch does not affect functions using the
+@code{extern inline} extension in GNU C89@. In C++, emit any and all
+inline functions into the object file.
@item -fkeep-static-consts
@opindex fkeep-static-consts
optimization is turned on, use the @option{-fno-keep-static-consts} option.
@item -fmerge-constants
+@opindex fmerge-constants
Attempt to merge identical constants (string constants and floating point
-constants) accross compilation units.
+constants) across compilation units.
-This option is default for optimized compilation if assembler and linker
-support it. Use @option{-fno-merge-constants} to inhibit this behavior.
+This option is the default for optimized compilation if the assembler and
+linker support it. Use @option{-fno-merge-constants} to inhibit this
+behavior.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
@item -fmerge-all-constants
+@opindex fmerge-all-constants
Attempt to merge identical constants and identical variables.
This option implies @option{-fmerge-constants}. In addition to
-@option{-fmerge-constants} this considers e.g. even constant initialized
+@option{-fmerge-constants} this considers e.g.@: even constant initialized
arrays or initialized constant variables with integral or floating point
-types. Languages like C or C++ require each non-automatic variable to
-have distinct location, so using this option will result in non-conforming
+types. Languages like C or C++ require each variable, including multiple
+instances of the same variable in recursive calls, to have distinct locations,
+so using this option will result in non-conforming
behavior.
+@item -fmodulo-sched
+@opindex fmodulo-sched
+Perform swing modulo scheduling immediately before the first scheduling
+pass. This pass looks at innermost loops and reorders their
+instructions by overlapping different iterations.
+
+@item -fmodulo-sched-allow-regmoves
+@opindex fmodulo-sched-allow-regmoves
+Perform more aggressive SMS based modulo scheduling with register moves
+allowed. By setting this flag certain anti-dependences edges will be
+deleted which will trigger the generation of reg-moves based on the
+life-range analysis. This option is effective only with
+@option{-fmodulo-sched} enabled.
+
@item -fno-branch-count-reg
@opindex fno-branch-count-reg
Do not use ``decrement and branch'' instructions on a count register,
This option is only meaningful on architectures that support such
instructions, which include x86, PowerPC, IA-64 and S/390.
+The default is @option{-fbranch-count-reg}.
+
@item -fno-function-cse
@opindex fno-function-cse
Do not put function addresses in registers; make each instruction that
that alter the assembler output may be confused by the optimizations
performed when this option is not used.
-@item -ffast-math
-@opindex ffast-math
-Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations}, and @*
-@option{-fno-trapping-math}.
-
-This option causes the preprocessor macro @code{__FAST_MATH__} to be defined.
-
-This option should never be turned on by any @option{-O} option since
-it can result in incorrect output for programs which depend on
-an exact implementation of IEEE or ISO rules/specifications for
-math functions.
-
-@item -fno-math-errno
-@opindex fno-math-errno
-Do not set ERRNO after calling math functions that are executed
-with a single instruction, e.g., sqrt. A program that relies on
-IEEE exceptions for math error handling may want to use this flag
-for speed while maintaining IEEE arithmetic compatibility.
-
-This option should never be turned on by any @option{-O} option since
-it can result in incorrect output for programs which depend on
-an exact implementation of IEEE or ISO rules/specifications for
-math functions.
-
-The default is @option{-fmath-errno}.
-
-@item -funsafe-math-optimizations
-@opindex funsafe-math-optimizations
-Allow optimizations for floating-point arithmetic that (a) assume
-that arguments and results are valid and (b) may violate IEEE or
-ANSI standards. When used at link-time, it may include libraries
-or startup files that change the default FPU control word or other
-similar optimizations.
-
-This option should never be turned on by any @option{-O} option since
-it can result in incorrect output for programs which depend on
-an exact implementation of IEEE or ISO rules/specifications for
-math functions.
-
-The default is @option{-fno-unsafe-math-optimizations}.
-
-@item -fno-trapping-math
-@opindex fno-trapping-math
-Compile code assuming that floating-point operations cannot generate
-user-visible traps. Setting this option may allow faster code
-if one relies on ``non-stop'' IEEE arithmetic, for example.
-
-This option should never be turned on by any @option{-O} option since
-it can result in incorrect output for programs which depend on
-an exact implementation of IEEE or ISO rules/specifications for
-math functions.
-
-The default is @option{-ftrapping-math}.
-
-@item -fbounds-check
-@opindex fbounds-check
-For front-ends that support it, generate additional code to check that
-indices used to access arrays are within the declared range. This is
-currenly only supported by the Java and Fortran 77 front-ends, where
-this option defaults to true and false respectively.
-
-@end table
-
-The following options control specific optimizations. The @option{-O2}
-option turns on all of these optimizations except @option{-funroll-loops}
-and @option{-funroll-all-loops}. On most machines, the @option{-O} option
-turns on the @option{-fthread-jumps} and @option{-fdelayed-branch} options,
-but specific machines may handle it differently.
-
-You can use the following flags in the rare cases when ``fine-tuning''
-of optimizations to be performed is desired.
-
-Not all of the optimizations performed by GCC have @option{-f} options
-to control them.
-
-@table @gcctabopt
-@item -fstrength-reduce
-@opindex fstrength-reduce
-Perform the optimizations of loop strength reduction and
-elimination of iteration variables.
+The default is @option{-ffunction-cse}
+
+@item -fno-zero-initialized-in-bss
+@opindex fno-zero-initialized-in-bss
+If the target supports a BSS section, GCC by default puts variables that
+are initialized to zero into BSS@. This can save space in the resulting
+code.
+
+This option turns off this behavior because some programs explicitly
+rely on variables going to the data section. E.g., so that the
+resulting executable can find the beginning of that section and/or make
+assumptions based on that.
+
+The default is @option{-fzero-initialized-in-bss}.
+
+@item -fmudflap -fmudflapth -fmudflapir
+@opindex fmudflap
+@opindex fmudflapth
+@opindex fmudflapir
+@cindex bounds checking
+@cindex mudflap
+For front-ends that support it (C and C++), instrument all risky
+pointer/array dereferencing operations, some standard library
+string/heap functions, and some other associated constructs with
+range/validity tests. Modules so instrumented should be immune to
+buffer overflows, invalid heap use, and some other classes of C/C++
+programming errors. The instrumentation relies on a separate runtime
+library (@file{libmudflap}), which will be linked into a program if
+@option{-fmudflap} is given at link time. Run-time behavior of the
+instrumented program is controlled by the @env{MUDFLAP_OPTIONS}
+environment variable. See @code{env MUDFLAP_OPTIONS=-help a.out}
+for its options.
+
+Use @option{-fmudflapth} instead of @option{-fmudflap} to compile and to
+link if your program is multi-threaded. Use @option{-fmudflapir}, in
+addition to @option{-fmudflap} or @option{-fmudflapth}, if
+instrumentation should ignore pointer reads. This produces less
+instrumentation (and therefore faster execution) and still provides
+some protection against outright memory corrupting writes, but allows
+erroneously read data to propagate within a program.
@item -fthread-jumps
@opindex fthread-jumps
second branch or a point immediately following it, depending on whether
the condition is known to be true or false.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fsplit-wide-types
+@opindex fsplit-wide-types
+When using a type that occupies multiple registers, such as @code{long
+long} on a 32-bit system, split the registers apart and allocate them
+independently. This normally generates better code for those types,
+but may make debugging more difficult.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3},
+@option{-Os}.
+
@item -fcse-follow-jumps
@opindex fcse-follow-jumps
-In common subexpression elimination, scan through jump instructions
+In common subexpression elimination (CSE), scan through jump instructions
when the target of the jump is not reached by any other path. For
example, when CSE encounters an @code{if} statement with an
@code{else} clause, CSE will follow the jump when the condition
tested is false.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fcse-skip-blocks
@opindex fcse-skip-blocks
This is similar to @option{-fcse-follow-jumps}, but causes CSE to
@option{-fcse-skip-blocks} causes CSE to follow the jump around the
body of the @code{if}.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -frerun-cse-after-loop
@opindex frerun-cse-after-loop
Re-run common subexpression elimination after loop optimizations has been
performed.
-@item -frerun-loop-opt
-@opindex frerun-loop-opt
-Run the loop optimizer twice.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
@item -fgcse
@opindex fgcse
@emph{Note:} When compiling a program using computed gotos, a GCC
extension, you may get better runtime performance if you disable
-the global common subexpression elmination pass by adding
+the global common subexpression elimination pass by adding
@option{-fno-gcse} to the command line.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fgcse-lm
@opindex fgcse-lm
When @option{-fgcse-lm} is enabled, global common subexpression elimination will
allows a loop containing a load/store sequence to be changed to a load outside
the loop, and a copy/store within the loop.
+Enabled by default when gcse is enabled.
+
@item -fgcse-sm
@opindex fgcse-sm
-When @option{-fgcse-sm} is enabled, A store motion pass is run after global common
-subexpression elimination. This pass will attempt to move stores out of loops.
-When used in conjunction with @option{-fgcse-lm}, loops containing a load/store sequence
-can be changed to a load before the loop and a store after the loop.
+When @option{-fgcse-sm} is enabled, a store motion pass is run after
+global common subexpression elimination. This pass will attempt to move
+stores out of loops. When used in conjunction with @option{-fgcse-lm},
+loops containing a load/store sequence can be changed to a load before
+the loop and a store after the loop.
+
+Not enabled at any optimization level.
+
+@item -fgcse-las
+@opindex fgcse-las
+When @option{-fgcse-las} is enabled, the global common subexpression
+elimination pass eliminates redundant loads that come after stores to the
+same memory location (both partial and full redundancies).
+
+Not enabled at any optimization level.
+
+@item -fgcse-after-reload
+@opindex fgcse-after-reload
+When @option{-fgcse-after-reload} is enabled, a redundant load elimination
+pass is performed after reload. The purpose of this pass is to cleanup
+redundant spilling.
+
+@item -funsafe-loop-optimizations
+@opindex funsafe-loop-optimizations
+If given, the loop optimizer will assume that loop indices do not
+overflow, and that the loops with nontrivial exit condition are not
+infinite. This enables a wider range of loop optimizations even if
+the loop optimizer itself cannot prove that these assumptions are valid.
+Using @option{-Wunsafe-loop-optimizations}, the compiler will warn you
+if it finds this kind of loop.
+
+@item -fcrossjumping
+@opindex fcrossjumping
+Perform cross-jumping transformation. This transformation unifies equivalent code and save code size. The
+resulting code may or may not perform better than without cross-jumping.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fauto-inc-dec
+@opindex fauto-inc-dec
+Combine increments or decrements of addresses with memory accesses.
+This pass is always skipped on architectures that do not have
+instructions to support this. Enabled by default at @option{-O} and
+higher on architectures that support this.
+
+@item -fdce
+@opindex fdce
+Perform dead code elimination (DCE) on RTL@.
+Enabled by default at @option{-O} and higher.
+
+@item -fdse
+@opindex fdse
+Perform dead store elimination (DSE) on RTL@.
+Enabled by default at @option{-O} and higher.
+
+@item -fif-conversion
+@opindex fif-conversion
+Attempt to transform conditional jumps into branch-less equivalents. This
+include use of conditional moves, min, max, set flags and abs instructions, and
+some tricks doable by standard arithmetics. The use of conditional execution
+on chips where it is available is controlled by @code{if-conversion2}.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fif-conversion2
+@opindex fif-conversion2
+Use conditional execution (where available) to transform conditional jumps into
+branch-less equivalents.
+
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
@item -fdelete-null-pointer-checks
@opindex fdelete-null-pointer-checks
@option{-fno-delete-null-pointer-checks} to disable this optimization
for programs which depend on that behavior.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fexpensive-optimizations
@opindex fexpensive-optimizations
Perform a number of minor optimizations that are relatively expensive.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -foptimize-register-move
@itemx -fregmove
@opindex foptimize-register-move
Attempt to reassign register numbers in move instructions and as
operands of other simple instructions in order to maximize the amount of
register tying. This is especially helpful on machines with two-operand
-instructions. GCC enables this optimization by default with @option{-O2}
-or higher.
+instructions.
Note @option{-fregmove} and @option{-foptimize-register-move} are the same
optimization.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fira-algorithm=@var{algorithm}
+Use specified coloring algorithm for the integrated register
+allocator. The @var{algorithm} argument should be @code{priority} or
+@code{CB}. The first algorithm specifies Chow's priority coloring,
+the second one specifies Chaitin-Briggs coloring. The second
+algorithm can be unimplemented for some architectures. If it is
+implemented, it is the default because Chaitin-Briggs coloring as a
+rule generates a better code.
+
+@item -fira-region=@var{region}
+Use specified regions for the integrated register allocator. The
+@var{region} argument should be one of @code{all}, @code{mixed}, or
+@code{one}. The first value means using all loops as register
+allocation regions, the second value which is the default means using
+all loops except for loops with small register pressure as the
+regions, and third one means using all function as a single region.
+The first value can give best result for machines with small size and
+irregular register set, the third one results in faster and generates
+decent code and the smallest size code, and the default value usually
+give the best results in most cases and for most architectures.
+
+@item -fira-coalesce
+@opindex fira-coalesce
+Do optimistic register coalescing. This option might be profitable for
+architectures with big regular register files.
+
+@item -fno-ira-share-save-slots
+@opindex fno-ira-share-save-slots
+Switch off sharing stack slots used for saving call used hard
+registers living through a call. Each hard register will get a
+separate stack slot and as a result function stack frame will be
+bigger.
+
+@item -fno-ira-share-spill-slots
+@opindex fno-ira-share-spill-slots
+Switch off sharing stack slots allocated for pseudo-registers. Each
+pseudo-register which did not get a hard register will get a separate
+stack slot and as a result function stack frame will be bigger.
+
+@item -fira-verbose=@var{n}
+@opindex fira-verbose
+Set up how verbose dump file for the integrated register allocator
+will be. Default value is 5. If the value is greater or equal to 10,
+the dump file will be stderr as if the value were @var{n} minus 10.
+
@item -fdelayed-branch
@opindex fdelayed-branch
If supported for the target machine, attempt to reorder instructions
to exploit instruction slots available after delayed branch
instructions.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fschedule-insns
@opindex fschedule-insns
If supported for the target machine, attempt to reorder instructions to
by allowing other instructions to be issued until the result of the load
or floating point instruction is required.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fschedule-insns2
@opindex fschedule-insns2
Similar to @option{-fschedule-insns}, but requests an additional pass of
especially useful on machines with a relatively small number of
registers and where memory load instructions take more than one cycle.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
@item -fno-sched-interblock
@opindex fno-sched-interblock
Don't schedule instructions across basic blocks. This is normally
sense when scheduling before register allocation, i.e.@: with
@option{-fschedule-insns} or at @option{-O2} or higher.
-@item -ffunction-sections
-@itemx -fdata-sections
-@opindex ffunction-sections
-@opindex fdata-sections
-Place each function or data item into its own section in the output
-file if the target supports arbitrary sections. The name of the
-function or the name of the data item determines the section's name
-in the output file.
-
-Use these options on systems where the linker can perform optimizations
-to improve locality of reference in the instruction space. HPPA
-processors running HP-UX and Sparc processors running Solaris 2 have
-linkers with such optimizations. Other systems using the ELF object format
-as well as AIX may have these optimizations in the future.
-
-Only use these options when there are significant benefits from doing
-so. When you specify these options, the assembler and linker will
-create larger object and executable files and will also be slower.
-You will not be able to use @code{gprof} on all systems if you
-specify this option and you may have problems with debugging if
-you specify both this option and @option{-g}.
+@item -fsched-stalled-insns
+@itemx -fsched-stalled-insns=@var{n}
+@opindex fsched-stalled-insns
+Define how many insns (if any) can be moved prematurely from the queue
+of stalled insns into the ready list, during the second scheduling pass.
+@option{-fno-sched-stalled-insns} means that no insns will be moved
+prematurely, @option{-fsched-stalled-insns=0} means there is no limit
+on how many queued insns can be moved prematurely.
+@option{-fsched-stalled-insns} without a value is equivalent to
+@option{-fsched-stalled-insns=1}.
+
+@item -fsched-stalled-insns-dep
+@itemx -fsched-stalled-insns-dep=@var{n}
+@opindex fsched-stalled-insns-dep
+Define how many insn groups (cycles) will be examined for a dependency
+on a stalled insn that is candidate for premature removal from the queue
+of stalled insns. This has an effect only during the second scheduling pass,
+and only if @option{-fsched-stalled-insns} is used.
+@option{-fno-sched-stalled-insns-dep} is equivalent to
+@option{-fsched-stalled-insns-dep=0}.
+@option{-fsched-stalled-insns-dep} without a value is equivalent to
+@option{-fsched-stalled-insns-dep=1}.
+
+@item -fsched2-use-superblocks
+@opindex fsched2-use-superblocks
+When scheduling after register allocation, do use superblock scheduling
+algorithm. Superblock scheduling allows motion across basic block boundaries
+resulting on faster schedules. This option is experimental, as not all machine
+descriptions used by GCC model the CPU closely enough to avoid unreliable
+results from the algorithm.
+
+This only makes sense when scheduling after register allocation, i.e.@: with
+@option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsched2-use-traces
+@opindex fsched2-use-traces
+Use @option{-fsched2-use-superblocks} algorithm when scheduling after register
+allocation and additionally perform code duplication in order to increase the
+size of superblocks using tracer pass. See @option{-ftracer} for details on
+trace formation.
+
+This mode should produce faster but significantly longer programs. Also
+without @option{-fbranch-probabilities} the traces constructed may not
+match the reality and hurt the performance. This only makes
+sense when scheduling after register allocation, i.e.@: with
+@option{-fschedule-insns2} or at @option{-O2} or higher.
+
+@item -fsee
+@opindex fsee
+Eliminate redundant sign extension instructions and move the non-redundant
+ones to optimal placement using lazy code motion (LCM).
+
+@item -freschedule-modulo-scheduled-loops
+@opindex freschedule-modulo-scheduled-loops
+The modulo scheduling comes before the traditional scheduling, if a loop
+was modulo scheduled we may want to prevent the later scheduling passes
+from changing its schedule, we use this option to control that.
+
+@item -fselective-scheduling
+@opindex fselective-scheduling
+Schedule instructions using selective scheduling algorithm. Selective
+scheduling runs instead of the first scheduler pass.
+
+@item -fselective-scheduling2
+@opindex fselective-scheduling2
+Schedule instructions using selective scheduling algorithm. Selective
+scheduling runs instead of the second scheduler pass.
+
+@item -fsel-sched-pipelining
+@opindex fsel-sched-pipelining
+Enable software pipelining of innermost loops during selective scheduling.
+This option has no effect until one of @option{-fselective-scheduling} or
+@option{-fselective-scheduling2} is turned on.
+
+@item -fsel-sched-pipelining-outer-loops
+@opindex fsel-sched-pipelining-outer-loops
+When pipelining loops during selective scheduling, also pipeline outer loops.
+This option has no effect until @option{-fsel-sched-pipelining} is turned on.
@item -fcaller-saves
@opindex fcaller-saves
This option is always enabled by default on certain machines, usually
those which have no call-preserved registers to use instead.
-For all machines, optimization level 2 and higher enables this flag by
-default.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fconserve-stack
+@opindex fconserve-stack
+Attempt to minimize stack usage. The compiler will attempt to use less
+stack space, even if that makes the program slower. This option
+implies setting the @option{large-stack-frame} parameter to 100
+and the @option{large-stack-frame-growth} parameter to 400.
+
+@item -ftree-reassoc
+@opindex ftree-reassoc
+Perform reassociation on trees. This flag is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-pre
+@opindex ftree-pre
+Perform partial redundancy elimination (PRE) on trees. This flag is
+enabled by default at @option{-O2} and @option{-O3}.
+
+@item -ftree-fre
+@opindex ftree-fre
+Perform full redundancy elimination (FRE) on trees. The difference
+between FRE and PRE is that FRE only considers expressions
+that are computed on all paths leading to the redundant computation.
+This analysis is faster than PRE, though it exposes fewer redundancies.
+This flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-copy-prop
+@opindex ftree-copy-prop
+Perform copy propagation on trees. This pass eliminates unnecessary
+copy operations. This flag is enabled by default at @option{-O} and
+higher.
+
+@item -fipa-pure-const
+@opindex fipa-pure-const
+Discover which functions are pure or constant.
+Enabled by default at @option{-O} and higher.
+
+@item -fipa-reference
+@opindex fipa-reference
+Discover which static variables do not escape cannot escape the
+compilation unit.
+Enabled by default at @option{-O} and higher.
+
+@item -fipa-struct-reorg
+@opindex fipa-struct-reorg
+Perform structure reorganization optimization, that change C-like structures
+layout in order to better utilize spatial locality. This transformation is
+affective for programs containing arrays of structures. Available in two
+compilation modes: profile-based (enabled with @option{-fprofile-generate})
+or static (which uses built-in heuristics). Require @option{-fipa-type-escape}
+to provide the safety of this transformation. It works only in whole program
+mode, so it requires @option{-fwhole-program} and @option{-combine} to be
+enabled. Structures considered @samp{cold} by this transformation are not
+affected (see @option{--param struct-reorg-cold-struct-ratio=@var{value}}).
+
+With this flag, the program debug info reflects a new structure layout.
+
+@item -fipa-pta
+@opindex fipa-pta
+Perform interprocedural pointer analysis. This option is experimental
+and does not affect generated code.
+
+@item -fipa-cp
+@opindex fipa-cp
+Perform interprocedural constant propagation.
+This optimization analyzes the program to determine when values passed
+to functions are constants and then optimizes accordingly.
+This optimization can substantially increase performance
+if the application has constants passed to functions.
+This flag is enabled by default at @option{-O2}, @option{-Os} and @option{-O3}.
+
+@item -fipa-cp-clone
+@opindex fipa-cp-clone
+Perform function cloning to make interprocedural constant propagation stronger.
+When enabled, interprocedural constant propagation will perform function cloning
+when externally visible function can be called with constant arguments.
+Because this optimization can create multiple copies of functions,
+it may significantly increase code size
+(see @option{--param ipcp-unit-growth=@var{value}}).
+This flag is enabled by default at @option{-O3}.
+
+@item -fipa-matrix-reorg
+@opindex fipa-matrix-reorg
+Perform matrix flattening and transposing.
+Matrix flattening tries to replace a m-dimensional matrix
+with its equivalent n-dimensional matrix, where n < m.
+This reduces the level of indirection needed for accessing the elements
+of the matrix. The second optimization is matrix transposing that
+attempts to change the order of the matrix's dimensions in order to
+improve cache locality.
+Both optimizations need the @option{-fwhole-program} flag.
+Transposing is enabled only if profiling information is available.
+
+
+@item -ftree-sink
+@opindex ftree-sink
+Perform forward store motion on trees. This flag is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-ccp
+@opindex ftree-ccp
+Perform sparse conditional constant propagation (CCP) on trees. This
+pass only operates on local scalar variables and is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-switch-conversion
+Perform conversion of simple initializations in a switch to
+initializations from a scalar array. This flag is enabled by default
+at @option{-O2} and higher.
+
+@item -ftree-dce
+@opindex ftree-dce
+Perform dead code elimination (DCE) on trees. This flag is enabled by
+default at @option{-O} and higher.
+
+@item -ftree-builtin-call-dce
+@opindex ftree-builtin-call-dce
+Perform conditional dead code elimination (DCE) for calls to builtin functions
+that may set @code{errno} but are otherwise side-effect free. This flag is
+enabled by default at @option{-O2} and higher if @option{-Os} is not also
+specified.
+
+@item -ftree-dominator-opts
+@opindex ftree-dominator-opts
+Perform a variety of simple scalar cleanups (constant/copy
+propagation, redundancy elimination, range propagation and expression
+simplification) based on a dominator tree traversal. This also
+performs jump threading (to reduce jumps to jumps). This flag is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-dse
+@opindex ftree-dse
+Perform dead store elimination (DSE) on trees. A dead store is a store into
+a memory location which will later be overwritten by another store without
+any intervening loads. In this case the earlier store can be deleted. This
+flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-ch
+@opindex ftree-ch
+Perform loop header copying on trees. This is beneficial since it increases
+effectiveness of code motion optimizations. It also saves one jump. This flag
+is enabled by default at @option{-O} and higher. It is not enabled
+for @option{-Os}, since it usually increases code size.
+
+@item -ftree-loop-optimize
+@opindex ftree-loop-optimize
+Perform loop optimizations on trees. This flag is enabled by default
+at @option{-O} and higher.
+
+@item -ftree-loop-linear
+@opindex ftree-loop-linear
+Perform linear loop transformations on tree. This flag can improve cache
+performance and allow further loop optimizations to take place.
+
+@item -floop-interchange
+Perform loop interchange transformations on loops. Interchanging two
+nested loops switches the inner and outer loops. For example, given a
+loop like:
+@smallexample
+DO J = 1, M
+ DO I = 1, N
+ A(J, I) = A(J, I) * C
+ ENDDO
+ENDDO
+@end smallexample
+loop interchange will transform the loop as if the user had written:
+@smallexample
+DO I = 1, N
+ DO J = 1, M
+ A(J, I) = A(J, I) * C
+ ENDDO
+ENDDO
+@end smallexample
+which can be beneficial when @code{N} is larger than the caches,
+because in Fortran, the elements of an array are stored in memory
+contiguously by column, and the original loop iterates over rows,
+potentially creating at each access a cache miss. This optimization
+applies to all the languages supported by GCC and is not limited to
+Fortran. To use this code transformation, GCC has to be configured
+with @option{--with-ppl} and @option{--with-cloog} to enable the
+Graphite loop transformation infrastructure.
+
+@item -floop-strip-mine
+Perform loop strip mining transformations on loops. Strip mining
+splits a loop into two nested loops. The outer loop has strides
+equal to the strip size and the inner loop has strides of the
+original loop within a strip. For example, given a loop like:
+@smallexample
+DO I = 1, N
+ A(I) = A(I) + C
+ENDDO
+@end smallexample
+loop strip mining will transform the loop as if the user had written:
+@smallexample
+DO II = 1, N, 4
+ DO I = II, min (II + 3, N)
+ A(I) = A(I) + C
+ ENDDO
+ENDDO
+@end smallexample
+This optimization applies to all the languages supported by GCC and is
+not limited to Fortran. To use this code transformation, GCC has to
+be configured with @option{--with-ppl} and @option{--with-cloog} to
+enable the Graphite loop transformation infrastructure.
+
+@item -floop-block
+Perform loop blocking transformations on loops. Blocking strip mines
+each loop in the loop nest such that the memory accesses of the
+element loops fit inside caches. For example, given a loop like:
+@smallexample
+DO I = 1, N
+ DO J = 1, M
+ A(J, I) = B(I) + C(J)
+ ENDDO
+ENDDO
+@end smallexample
+loop blocking will transform the loop as if the user had written:
+@smallexample
+DO II = 1, N, 64
+ DO JJ = 1, M, 64
+ DO I = II, min (II + 63, N)
+ DO J = JJ, min (JJ + 63, M)
+ A(J, I) = B(I) + C(J)
+ ENDDO
+ ENDDO
+ ENDDO
+ENDDO
+@end smallexample
+which can be beneficial when @code{M} is larger than the caches,
+because the innermost loop will iterate over a smaller amount of data
+that can be kept in the caches. This optimization applies to all the
+languages supported by GCC and is not limited to Fortran. To use this
+code transformation, GCC has to be configured with @option{--with-ppl}
+and @option{--with-cloog} to enable the Graphite loop transformation
+infrastructure.
+
+@item -fcheck-data-deps
+@opindex fcheck-data-deps
+Compare the results of several data dependence analyzers. This option
+is used for debugging the data dependence analyzers.
+
+@item -ftree-loop-distribution
+Perform loop distribution. This flag can improve cache performance on
+big loop bodies and allow further loop optimizations, like
+parallelization or vectorization, to take place. For example, the loop
+@smallexample
+DO I = 1, N
+ A(I) = B(I) + C
+ D(I) = E(I) * F
+ENDDO
+@end smallexample
+is transformed to
+@smallexample
+DO I = 1, N
+ A(I) = B(I) + C
+ENDDO
+DO I = 1, N
+ D(I) = E(I) * F
+ENDDO
+@end smallexample
+
+@item -ftree-loop-im
+@opindex ftree-loop-im
+Perform loop invariant motion on trees. This pass moves only invariants that
+would be hard to handle at RTL level (function calls, operations that expand to
+nontrivial sequences of insns). With @option{-funswitch-loops} it also moves
+operands of conditions that are invariant out of the loop, so that we can use
+just trivial invariantness analysis in loop unswitching. The pass also includes
+store motion.
+
+@item -ftree-loop-ivcanon
+@opindex ftree-loop-ivcanon
+Create a canonical counter for number of iterations in the loop for that
+determining number of iterations requires complicated analysis. Later
+optimizations then may determine the number easily. Useful especially
+in connection with unrolling.
+
+@item -fivopts
+@opindex fivopts
+Perform induction variable optimizations (strength reduction, induction
+variable merging and induction variable elimination) on trees.
+
+@item -ftree-parallelize-loops=n
+@opindex ftree-parallelize-loops
+Parallelize loops, i.e., split their iteration space to run in n threads.
+This is only possible for loops whose iterations are independent
+and can be arbitrarily reordered. The optimization is only
+profitable on multiprocessor machines, for loops that are CPU-intensive,
+rather than constrained e.g.@: by memory bandwidth. This option
+implies @option{-pthread}, and thus is only supported on targets
+that have support for @option{-pthread}.
+
+@item -ftree-sra
+@opindex ftree-sra
+Perform scalar replacement of aggregates. This pass replaces structure
+references with scalars to prevent committing structures to memory too
+early. This flag is enabled by default at @option{-O} and higher.
+
+@item -ftree-copyrename
+@opindex ftree-copyrename
+Perform copy renaming on trees. This pass attempts to rename compiler
+temporaries to other variables at copy locations, usually resulting in
+variable names which more closely resemble the original variables. This flag
+is enabled by default at @option{-O} and higher.
+
+@item -ftree-ter
+@opindex ftree-ter
+Perform temporary expression replacement during the SSA->normal phase. Single
+use/single def temporaries are replaced at their use location with their
+defining expression. This results in non-GIMPLE code, but gives the expanders
+much more complex trees to work on resulting in better RTL generation. This is
+enabled by default at @option{-O} and higher.
+
+@item -ftree-vectorize
+@opindex ftree-vectorize
+Perform loop vectorization on trees. This flag is enabled by default at
+@option{-O3}.
+
+@item -ftree-vect-loop-version
+@opindex ftree-vect-loop-version
+Perform loop versioning when doing loop vectorization on trees. When a loop
+appears to be vectorizable except that data alignment or data dependence cannot
+be determined at compile time then vectorized and non-vectorized versions of
+the loop are generated along with runtime checks for alignment or dependence
+to control which version is executed. This option is enabled by default
+except at level @option{-Os} where it is disabled.
+
+@item -fvect-cost-model
+@opindex fvect-cost-model
+Enable cost model for vectorization.
+
+@item -ftree-vrp
+@opindex ftree-vrp
+Perform Value Range Propagation on trees. This is similar to the
+constant propagation pass, but instead of values, ranges of values are
+propagated. This allows the optimizers to remove unnecessary range
+checks like array bound checks and null pointer checks. This is
+enabled by default at @option{-O2} and higher. Null pointer check
+elimination is only done if @option{-fdelete-null-pointer-checks} is
+enabled.
+
+@item -ftracer
+@opindex ftracer
+Perform tail duplication to enlarge superblock size. This transformation
+simplifies the control flow of the function allowing other optimizations to do
+better job.
@item -funroll-loops
@opindex funroll-loops
Unroll loops whose number of iterations can be determined at compile
-time or upon entry to the loop. @option{-funroll-loops} implies both
-@option{-fstrength-reduce} and @option{-frerun-cse-after-loop}. This
-option makes code larger, and may or may not make it run faster.
+time or upon entry to the loop. @option{-funroll-loops} implies
+@option{-frerun-cse-after-loop}. This option makes code larger,
+and may or may not make it run faster.
@item -funroll-all-loops
@opindex funroll-all-loops
@option{-funroll-all-loops} implies the same options as
@option{-funroll-loops},
+@item -fsplit-ivs-in-unroller
+@opindex fsplit-ivs-in-unroller
+Enables expressing of values of induction variables in later iterations
+of the unrolled loop using the value in the first iteration. This breaks
+long dependency chains, thus improving efficiency of the scheduling passes.
+
+Combination of @option{-fweb} and CSE is often sufficient to obtain the
+same effect. However in cases the loop body is more complicated than
+a single basic block, this is not reliable. It also does not work at all
+on some of the architectures due to restrictions in the CSE pass.
+
+This optimization is enabled by default.
+
+@item -fvariable-expansion-in-unroller
+@opindex fvariable-expansion-in-unroller
+With this option, the compiler will create multiple copies of some
+local variables when unrolling a loop which can result in superior code.
+
+@item -fpredictive-commoning
+@opindex fpredictive-commoning
+Perform predictive commoning optimization, i.e., reusing computations
+(especially memory loads and stores) performed in previous
+iterations of loops.
+
+This option is enabled at level @option{-O3}.
+
@item -fprefetch-loop-arrays
@opindex fprefetch-loop-arrays
If supported by the target machine, generate instructions to prefetch
memory to improve the performance of loops that access large arrays.
-@item -fmove-all-movables
-@opindex fmove-all-movables
-Forces all invariant computations in loops to be moved
-outside the loop.
-
-@item -freduce-all-givs
-@opindex freduce-all-givs
-Forces all general-induction variables in loops to be
-strength-reduced.
-
-@emph{Note:} When compiling programs written in Fortran,
-@option{-fmove-all-movables} and @option{-freduce-all-givs} are enabled
-by default when you use the optimizer.
-
-These options may generate better or worse code; results are highly
+This option may generate better or worse code; results are highly
dependent on the structure of loops within the source code.
-These two options are intended to be removed someday, once
-they have helped determine the efficacy of various
-approaches to improving loop optimizations.
-
-Please let us (@w{@email{gcc@@gcc.gnu.org}} and @w{@email{fortran@@gnu.org}})
-know how use of these options affects
-the performance of your production code.
-We're very interested in code that runs @emph{slower}
-when these options are @emph{enabled}.
+Disabled at level @option{-Os}.
@item -fno-peephole
@itemx -fno-peephole2
are implemented in the compiler; some targets use one, some use the
other, a few use both.
-@item -fbranch-probabilities
-@opindex fbranch-probabilities
-After running a program compiled with @option{-fprofile-arcs}
-(@pxref{Debugging Options,, Options for Debugging Your Program or
-@command{gcc}}), you can compile it a second time using
-@option{-fbranch-probabilities}, to improve optimizations based on
-the number of times each branch was taken. When the program
-compiled with @option{-fprofile-arcs} exits it saves arc execution
-counts to a file called @file{@var{sourcename}.da} for each source
-file The information in this data file is very dependent on the
-structure of the generated code, so you must use the same source code
-and the same optimization options for both compilations.
-
-With @option{-fbranch-probabilities}, GCC puts a @samp{REG_EXEC_COUNT}
-note on the first instruction of each basic block, and a
-@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}.
-These can be used to improve optimization. Currently, they are only
-used in one place: in @file{reorg.c}, instead of guessing which path a
-branch is mostly to take, the @samp{REG_BR_PROB} values are used to
-exactly determine which path is taken more often.
+@option{-fpeephole} is enabled by default.
+@option{-fpeephole2} enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
@item -fno-guess-branch-probability
@opindex fno-guess-branch-probability
-Do not guess branch probabilities using a randomized model.
-
-Sometimes gcc will opt to use a randomized model to guess branch
-probabilities, when none are available from either profiling feedback
-(@option{-fprofile-arcs}) or @samp{__builtin_expect}. This means that
-different runs of the compiler on the same program may produce different
-object code.
-
-In a hard real-time system, people don't want different runs of the
-compiler to produce code that has different behavior; minimizing
-non-determinism is of paramount import. This switch allows users to
-reduce non-determinism, possibly at the expense of inferior
-optimization.
+Do not guess branch probabilities using heuristics.
+
+GCC will use heuristics to guess branch probabilities if they are
+not provided by profiling feedback (@option{-fprofile-arcs}). These
+heuristics are based on the control flow graph. If some branch probabilities
+are specified by @samp{__builtin_expect}, then the heuristics will be
+used to guess branch probabilities for the rest of the control flow graph,
+taking the @samp{__builtin_expect} info into account. The interactions
+between the heuristics and @samp{__builtin_expect} can be complex, and in
+some cases, it may be useful to disable the heuristics so that the effects
+of @samp{__builtin_expect} are easier to understand.
+
+The default is @option{-fguess-branch-probability} at levels
+@option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -freorder-blocks
+@opindex freorder-blocks
+Reorder basic blocks in the compiled function in order to reduce number of
+taken branches and improve code locality.
+
+Enabled at levels @option{-O2}, @option{-O3}.
+
+@item -freorder-blocks-and-partition
+@opindex freorder-blocks-and-partition
+In addition to reordering basic blocks in the compiled function, in order
+to reduce number of taken branches, partitions hot and cold basic blocks
+into separate sections of the assembly and .o files, to improve
+paging and cache locality performance.
+
+This optimization is automatically turned off in the presence of
+exception handling, for linkonce sections, for functions with a user-defined
+section attribute and on any architecture that does not support named
+sections.
+
+@item -freorder-functions
+@opindex freorder-functions
+Reorder functions in the object file in order to
+improve code locality. This is implemented by using special
+subsections @code{.text.hot} for most frequently executed functions and
+@code{.text.unlikely} for unlikely executed functions. Reordering is done by
+the linker so object file format must support named sections and linker must
+place them in a reasonable way.
+
+Also profile feedback must be available in to make this option effective. See
+@option{-fprofile-arcs} for details.
+
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os}.
@item -fstrict-aliasing
@opindex fstrict-aliasing
-Allows the compiler to assume the strictest aliasing rules applicable to
+Allow the compiler to assume the strictest aliasing rules applicable to
the language being compiled. For C (and C++), this activates
optimizations based on the type of expressions. In particular, an
object of one type is assumed never to reside at the same address as an
@code{void*} or a @code{double}. A character type may alias any other
type.
-Pay special attention to code like this:
-@example
+@anchor{Type-punning}Pay special attention to code like this:
+@smallexample
union a_union @{
int i;
double d;
@};
int f() @{
- a_union t;
+ union a_union t;
t.d = 3.0;
return t.i;
@}
-@end example
+@end smallexample
The practice of reading from a different union member than the one most
recently written to (called ``type-punning'') is common. Even with
@option{-fstrict-aliasing}, type-punning is allowed, provided the memory
is accessed through the union type. So, the code above will work as
-expected. However, this code might not:
-@example
+expected. @xref{Structures unions enumerations and bit-fields
+implementation}. However, this code might not:
+@smallexample
int f() @{
- a_union t;
+ union a_union t;
int* ip;
t.d = 3.0;
ip = &t.i;
return *ip;
@}
-@end example
+@end smallexample
+
+Similarly, access by taking the address, casting the resulting pointer
+and dereferencing the result has undefined behavior, even if the cast
+uses a union type, e.g.:
+@smallexample
+int f() @{
+ double d = 3.0;
+ return ((union a_union *) &d)->i;
+@}
+@end smallexample
-Every language that wishes to perform language-specific alias analysis
-should define a function that computes, given an @code{tree}
-node, an alias set for the node. Nodes in different alias sets are not
-allowed to alias. For an example, see the C front-end function
-@code{c_get_alias_set}.
+The @option{-fstrict-aliasing} option is enabled at levels
+@option{-O2}, @option{-O3}, @option{-Os}.
+
+@item -fstrict-overflow
+@opindex fstrict-overflow
+Allow the compiler to assume strict signed overflow rules, depending
+on the language being compiled. For C (and C++) this means that
+overflow when doing arithmetic with signed numbers is undefined, which
+means that the compiler may assume that it will not happen. This
+permits various optimizations. For example, the compiler will assume
+that an expression like @code{i + 10 > i} will always be true for
+signed @code{i}. This assumption is only valid if signed overflow is
+undefined, as the expression is false if @code{i + 10} overflows when
+using twos complement arithmetic. When this option is in effect any
+attempt to determine whether an operation on signed numbers will
+overflow must be written carefully to not actually involve overflow.
+
+This option also allows the compiler to assume strict pointer
+semantics: given a pointer to an object, if adding an offset to that
+pointer does not produce a pointer to the same object, the addition is
+undefined. This permits the compiler to conclude that @code{p + u >
+p} is always true for a pointer @code{p} and unsigned integer
+@code{u}. This assumption is only valid because pointer wraparound is
+undefined, as the expression is false if @code{p + u} overflows using
+twos complement arithmetic.
+
+See also the @option{-fwrapv} option. Using @option{-fwrapv} means
+that integer signed overflow is fully defined: it wraps. When
+@option{-fwrapv} is used, there is no difference between
+@option{-fstrict-overflow} and @option{-fno-strict-overflow} for
+integers. With @option{-fwrapv} certain types of overflow are
+permitted. For example, if the compiler gets an overflow when doing
+arithmetic on constants, the overflowed value can still be used with
+@option{-fwrapv}, but not otherwise.
+
+The @option{-fstrict-overflow} option is enabled at levels
+@option{-O2}, @option{-O3}, @option{-Os}.
@item -falign-functions
@itemx -falign-functions=@var{n}
Some assemblers only support this flag when @var{n} is a power of two;
in that case, it is rounded up.
-If @var{n} is not specified, use a machine-dependent default.
+If @var{n} is not specified or is zero, use a machine-dependent default.
+
+Enabled at levels @option{-O2}, @option{-O3}.
@item -falign-labels
@itemx -falign-labels=@var{n}
make code slower, because it must insert dummy operations for when the
branch target is reached in the usual flow of the code.
+@option{-fno-align-labels} and @option{-falign-labels=1} are
+equivalent and mean that labels will not be aligned.
+
If @option{-falign-loops} or @option{-falign-jumps} are applicable and
are greater than this value, then their values are used instead.
-If @var{n} is not specified, use a machine-dependent default which is
-very likely to be @samp{1}, meaning no alignment.
+If @var{n} is not specified or is zero, use a machine-dependent default
+which is very likely to be @samp{1}, meaning no alignment.
+
+Enabled at levels @option{-O2}, @option{-O3}.
@item -falign-loops
@itemx -falign-loops=@var{n}
executed many times, which will make up for any execution of the dummy
operations.
-If @var{n} is not specified, use a machine-dependent default.
+@option{-fno-align-loops} and @option{-falign-loops=1} are
+equivalent and mean that loops will not be aligned.
+
+If @var{n} is not specified or is zero, use a machine-dependent default.
+
+Enabled at levels @option{-O2}, @option{-O3}.
@item -falign-jumps
@itemx -falign-jumps=@var{n}
bytes like @option{-falign-functions}. In this case, no dummy operations
need be executed.
-If @var{n} is not specified, use a machine-dependent default.
+@option{-fno-align-jumps} and @option{-falign-jumps=1} are
+equivalent and mean that loops will not be aligned.
-@item -fssa
-@opindex fssa
-Perform optimizations in static single assignment form. Each function's
-flow graph is translated into SSA form, optimizations are performed, and
-the flow graph is translated back from SSA form. Users should not
-specify this option, since it is not yet ready for production use.
+If @var{n} is not specified or is zero, use a machine-dependent default.
-@item -fssa-ccp
-@opindex fssa-ccp
-Perform Sparse Conditional Constant Propagation in SSA form. Requires
-@option{-fssa}. Like @option{-fssa}, this is an experimental feature.
+Enabled at levels @option{-O2}, @option{-O3}.
-@item -fssa-dce
-@opindex fssa-dce
-Perform aggressive dead-code elimination in SSA form. Requires @option{-fssa}.
-Like @option{-fssa}, this is an experimental feature.
+@item -funit-at-a-time
+@opindex funit-at-a-time
+This option is left for compatibility reasons. @option{-funit-at-a-time}
+has no effect, while @option{-fno-unit-at-a-time} implies
+@option{-fno-toplevel-reorder} and @option{-fno-section-anchors}.
-@item -fsingle-precision-constant
-@opindex fsingle-precision-constant
-Treat floating point constant as single precision constant instead of
-implicitly converting it to double precision constant.
+Enabled by default.
-@item -frename-registers
-@opindex frename-registers
-Attempt to avoid false dependencies in scheduled code by making use
-of registers left over after register allocation. This optimization
-will most benefit processors with lots of registers. It can, however,
-make debugging impossible, since variables will no longer stay in
-a ``home register''.
+@item -fno-toplevel-reorder
+@opindex fno-toplevel-reorder
+Do not reorder top-level functions, variables, and @code{asm}
+statements. Output them in the same order that they appear in the
+input file. When this option is used, unreferenced static variables
+will not be removed. This option is intended to support existing code
+which relies on a particular ordering. For new code, it is better to
+use attributes.
+
+Enabled at level @option{-O0}. When disabled explicitly, it also imply
+@option{-fno-section-anchors} that is otherwise enabled at @option{-O0} on some
+targets.
-@item -fno-cprop-registers
-@opindex fno-cprop-registers
+@item -fweb
+@opindex fweb
+Constructs webs as commonly used for register allocation purposes and assign
+each web individual pseudo register. This allows the register allocation pass
+to operate on pseudos directly, but also strengthens several other optimization
+passes, such as CSE, loop optimizer and trivial dead code remover. It can,
+however, make debugging impossible, since variables will no longer stay in a
+``home register''.
+
+Enabled by default with @option{-funroll-loops}.
+
+@item -fwhole-program
+@opindex fwhole-program
+Assume that the current compilation unit represents whole program being
+compiled. All public functions and variables with the exception of @code{main}
+and those merged by attribute @code{externally_visible} become static functions
+and in a affect gets more aggressively optimized by interprocedural optimizers.
+While this option is equivalent to proper use of @code{static} keyword for
+programs consisting of single file, in combination with option
+@option{--combine} this flag can be used to compile most of smaller scale C
+programs since the functions and variables become local for the whole combined
+compilation unit, not for the single source file itself.
+
+This option is not supported for Fortran programs.
+
+@item -fcprop-registers
+@opindex fcprop-registers
After register allocation and post-register allocation instruction splitting,
we perform a copy-propagation pass to try to reduce scheduling dependencies
and occasionally eliminate the copy.
-@item --param @var{name}=@var{value}
-@opindex param
-In some places, GCC uses various constants to control the amount of
-optimization that is done. For example, GCC will not inline functions
-that contain more that a certain number of instructions. You can
-control some of these constants on the command-line using the
-@option{--param} option.
-
-In each case, the @var{value} is an integer. The allowable choices for
-@var{name} are given in the following table:
-
-@table @gcctabopt
-@item max-delay-slot-insn-search
-The maximum number of instructions to consider when looking for an
-instruction to fill a delay slot. If more than this arbitrary number of
-instructions is searched, the time savings from filling the delay slot
-will be minimal so stop searching. Increasing values mean more
-aggressive optimization, making the compile time increase with probably
-small improvement in executable run time.
-
-@item max-delay-slot-live-search
-When trying to fill delay slots, the maximum number of instructions to
-consider when searching for a block with valid live register
-information. Increasing this arbitrarily chosen value means more
-aggressive optimization, increasing the compile time. This parameter
-should be removed when the delay slot code is rewritten to maintain the
-control-flow graph.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
-@item max-gcse-memory
-The approximate maximum amount of memory that will be allocated in
-order to perform the global common subexpression elimination
-optimization. If more memory than specified is required, the
-optimization will not be done.
+@item -fprofile-correction
+@opindex fprofile-correction
+Profiles collected using an instrumented binary for multi-threaded programs may
+be inconsistent due to missed counter updates. When this option is specified,
+GCC will use heuristics to correct or smooth out such inconsistencies. By
+default, GCC will emit an error message when an inconsistent profile is detected.
-@item max-gcse-passes
-The maximum number of passes of GCSE to run.
+@item -fprofile-dir=@var{path}
+@opindex fprofile-dir
-@item max-pending-list-length
-The maximum number of pending dependencies scheduling will allow
-before flushing the current state and starting over. Large functions
-with few branches or calls can create excessively large lists which
-needlessly consume memory and resources.
+Set the directory to search the profile data files in to @var{path}.
+This option affects only the profile data generated by
+@option{-fprofile-generate}, @option{-ftest-coverage}, @option{-fprofile-arcs}
+and used by @option{-fprofile-use} and @option{-fbranch-probabilities}
+and its related options.
+By default, GCC will use the current directory as @var{path}
+thus the profile data file will appear in the same directory as the object file.
-@item max-inline-insns
-If an function contains more than this many instructions, it
-will not be inlined. This option is precisely equivalent to
-@option{-finline-limit}.
+@item -fprofile-generate
+@itemx -fprofile-generate=@var{path}
+@opindex fprofile-generate
-@end table
-@end table
+Enable options usually used for instrumenting application to produce
+profile useful for later recompilation with profile feedback based
+optimization. You must use @option{-fprofile-generate} both when
+compiling and when linking your program.
-@node Preprocessor Options
-@section Options Controlling the Preprocessor
-@cindex preprocessor options
-@cindex options, preprocessor
+The following options are enabled: @code{-fprofile-arcs}, @code{-fprofile-values}, @code{-fvpt}.
-These options control the C preprocessor, which is run on each C source
-file before actual compilation.
+If @var{path} is specified, GCC will look at the @var{path} to find
+the profile feedback data files. See @option{-fprofile-dir}.
-If you use the @option{-E} option, nothing is done except preprocessing.
-Some of these options make sense only together with @option{-E} because
-they cause the preprocessor output to be unsuitable for actual
-compilation.
+@item -fprofile-use
+@itemx -fprofile-use=@var{path}
+@opindex fprofile-use
+Enable profile feedback directed optimizations, and optimizations
+generally profitable only with profile feedback available.
-@opindex Wp
-You can use @option{-Wp,@var{option}} to bypass the compiler driver
-and pass @var{option} directly through to the preprocessor. If
-@var{option} contains commas, it is split into multiple options at the
-commas. However, many options are modified, translated or interpreted
-by the compiler driver before being passed to the preprocessor, and
-@option{-Wp} forcibly bypasses this phase. The preprocessor's direct
-interface is undocumented and subject to change, so whenever possible
-you should avoid using @option{-Wp} and let the driver handle the
-options instead.
+The following options are enabled: @code{-fbranch-probabilities}, @code{-fvpt},
+@code{-funroll-loops}, @code{-fpeel-loops}, @code{-ftracer}
-@include cppopts.texi
+By default, GCC emits an error message if the feedback profiles do not
+match the source code. This error can be turned into a warning by using
+@option{-Wcoverage-mismatch}. Note this may result in poorly optimized
+code.
-@node Assembler Options
-@section Passing Options to the Assembler
+If @var{path} is specified, GCC will look at the @var{path} to find
+the profile feedback data files. See @option{-fprofile-dir}.
+@end table
-@c prevent bad page break with this line
-You can pass options to the assembler.
+The following options control compiler behavior regarding floating
+point arithmetic. These options trade off between speed and
+correctness. All must be specifically enabled.
@table @gcctabopt
-@item -Wa,@var{option}
-@opindex Wa
-Pass @var{option} as an option to the assembler. If @var{option}
-contains commas, it is split into multiple options at the commas.
-@end table
-
-@node Link Options
-@section Options for Linking
-@cindex link options
-@cindex options, linking
+@item -ffloat-store
+@opindex ffloat-store
+Do not store floating point variables in registers, and inhibit other
+options that might change whether a floating point value is taken from a
+register or memory.
-These options come into play when the compiler links object files into
-an executable output file. They are meaningless if the compiler is
-not doing a link step.
+@cindex floating point precision
+This option prevents undesirable excess precision on machines such as
+the 68000 where the floating registers (of the 68881) keep more
+precision than a @code{double} is supposed to have. Similarly for the
+x86 architecture. For most programs, the excess precision does only
+good, but a few programs rely on the precise definition of IEEE floating
+point. Use @option{-ffloat-store} for such programs, after modifying
+them to store all pertinent intermediate computations into variables.
-@table @gcctabopt
-@cindex file names
-@item @var{object-file-name}
-A file name that does not end in a special recognized suffix is
-considered to name an object file or library. (Object files are
-distinguished from libraries by the linker according to the file
-contents.) If linking is done, these object files are used as input
-to the linker.
+@item -ffast-math
+@opindex ffast-math
+Sets @option{-fno-math-errno}, @option{-funsafe-math-optimizations},
+@option{-ffinite-math-only}, @option{-fno-rounding-math},
+@option{-fno-signaling-nans} and @option{-fcx-limited-range}.
-@item -c
-@itemx -S
-@itemx -E
-@opindex c
-@opindex S
-@opindex E
-If any of these options is used, then the linker is not run, and
-object file names should not be used as arguments. @xref{Overall
-Options}.
+This option causes the preprocessor macro @code{__FAST_MATH__} to be defined.
-@cindex Libraries
-@item -l@var{library}
-@itemx -l @var{library}
-@opindex l
-Search the library named @var{library} when linking. (The second
-alternative with the library as a separate argument is only for
-POSIX compliance and is not recommended.)
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
-It makes a difference where in the command you write this option; the
-linker searches and processes libraries and object files in the order they
-are specified. Thus, @samp{foo.o -lz bar.o} searches library @samp{z}
-after file @file{foo.o} but before @file{bar.o}. If @file{bar.o} refers
-to functions in @samp{z}, those functions may not be loaded.
+@item -fno-math-errno
+@opindex fno-math-errno
+Do not set ERRNO after calling math functions that are executed
+with a single instruction, e.g., sqrt. A program that relies on
+IEEE exceptions for math error handling may want to use this flag
+for speed while maintaining IEEE arithmetic compatibility.
-The linker searches a standard list of directories for the library,
-which is actually a file named @file{lib@var{library}.a}. The linker
-then uses this file as if it had been specified precisely by name.
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
-The directories searched include several standard system directories
-plus any that you specify with @option{-L}.
+The default is @option{-fmath-errno}.
-Normally the files found this way are library files---archive files
-whose members are object files. The linker handles an archive file by
-scanning through it for members which define symbols that have so far
-been referenced but not defined. But if the file that is found is an
-ordinary object file, it is linked in the usual fashion. The only
-difference between using an @option{-l} option and specifying a file name
-is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a}
-and searches several directories.
+On Darwin systems, the math library never sets @code{errno}. There is
+therefore no reason for the compiler to consider the possibility that
+it might, and @option{-fno-math-errno} is the default.
-@item -lobjc
-@opindex lobjc
-You need this special case of the @option{-l} option in order to
-link an Objective-C program.
+@item -funsafe-math-optimizations
+@opindex funsafe-math-optimizations
-@item -nostartfiles
-@opindex nostartfiles
-Do not use the standard system startup files when linking.
-The standard system libraries are used normally, unless @option{-nostdlib}
-or @option{-nodefaultlibs} is used.
+Allow optimizations for floating-point arithmetic that (a) assume
+that arguments and results are valid and (b) may violate IEEE or
+ANSI standards. When used at link-time, it may include libraries
+or startup files that change the default FPU control word or other
+similar optimizations.
-@item -nodefaultlibs
-@opindex nodefaultlibs
-Do not use the standard system libraries when linking.
-Only the libraries you specify will be passed to the linker.
-The standard startup files are used normally, unless @option{-nostartfiles}
-is used. The compiler may generate calls to memcmp, memset, and memcpy
-for System V (and ISO C) environments or to bcopy and bzero for
-BSD environments. These entries are usually resolved by entries in
-libc. These entry points should be supplied through some other
-mechanism when this option is specified.
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
+Enables @option{-fno-signed-zeros}, @option{-fno-trapping-math},
+@option{-fassociative-math} and @option{-freciprocal-math}.
-@item -nostdlib
-@opindex nostdlib
-Do not use the standard system startup files or libraries when linking.
-No startup files and only the libraries you specify will be passed to
-the linker. The compiler may generate calls to memcmp, memset, and memcpy
-for System V (and ISO C) environments or to bcopy and bzero for
-BSD environments. These entries are usually resolved by entries in
-libc. These entry points should be supplied through some other
-mechanism when this option is specified.
+The default is @option{-fno-unsafe-math-optimizations}.
-@cindex @option{-lgcc}, use with @option{-nostdlib}
-@cindex @option{-nostdlib} and unresolved references
-@cindex unresolved references and @option{-nostdlib}
-@cindex @option{-lgcc}, use with @option{-nodefaultlibs}
-@cindex @option{-nodefaultlibs} and unresolved references
-@cindex unresolved references and @option{-nodefaultlibs}
-One of the standard libraries bypassed by @option{-nostdlib} and
-@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines
-that GCC uses to overcome shortcomings of particular machines, or special
-needs for some languages.
-(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler
-Collection (GCC) Internals},
-for more discussion of @file{libgcc.a}.)
-In most cases, you need @file{libgcc.a} even when you want to avoid
-other standard libraries. In other words, when you specify @option{-nostdlib}
-or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well.
-This ensures that you have no unresolved references to internal GCC
-library subroutines. (For example, @samp{__main}, used to ensure C++
-constructors will be called; @pxref{Collect2,,@code{collect2}, gccint,
-GNU Compiler Collection (GCC) Internals}.)
+@item -fassociative-math
+@opindex fassociative-math
-@item -s
-@opindex s
-Remove all symbol table and relocation information from the executable.
+Allow re-association of operands in series of floating-point operations.
+This violates the ISO C and C++ language standard by possibly changing
+computation result. NOTE: re-ordering may change the sign of zero as
+well as ignore NaNs and inhibit or create underflow or overflow (and
+thus cannot be used on a code which relies on rounding behavior like
+@code{(x + 2**52) - 2**52)}. May also reorder floating-point comparisons
+and thus may not be used when ordered comparisons are required.
+This option requires that both @option{-fno-signed-zeros} and
+@option{-fno-trapping-math} be in effect. Moreover, it doesn't make
+much sense with @option{-frounding-math}.
-@item -static
-@opindex static
-On systems that support dynamic linking, this prevents linking with the shared
-libraries. On other systems, this option has no effect.
+The default is @option{-fno-associative-math}.
-@item -shared
-@opindex shared
-Produce a shared object which can then be linked with other objects to
-form an executable. Not all systems support this option. For predictable
-results, you must also specify the same set of options that were used to
-generate code (@option{-fpic}, @option{-fPIC}, or model suboptions)
-when you specify this option.@footnote{On some systems, @samp{gcc -shared}
-needs to build supplementary stub code for constructors to work. On
-multi-libbed systems, @samp{gcc -shared} must select the correct support
-libraries to link against. Failing to supply the correct flags may lead
-to subtle defects. Supplying them in cases where they are not necessary
-is innocuous.}
+@item -freciprocal-math
+@opindex freciprocal-math
-@item -shared-libgcc
-@itemx -static-libgcc
-@opindex shared-libgcc
-@opindex static-libgcc
-On systems that provide @file{libgcc} as a shared library, these options
-force the use of either the shared or static version respectively.
-If no shared version of @file{libgcc} was built when the compiler was
-configured, these options have no effect.
+Allow the reciprocal of a value to be used instead of dividing by
+the value if this enables optimizations. For example @code{x / y}
+can be replaced with @code{x * (1/y)} which is useful if @code{(1/y)}
+is subject to common subexpression elimination. Note that this loses
+precision and increases the number of flops operating on the value.
-There are several situations in which an application should use the
-shared @file{libgcc} instead of the static version. The most common
-of these is when the application wishes to throw and catch exceptions
-across different shared libraries. In that case, each of the libraries
-as well as the application itself should use the shared @file{libgcc}.
+The default is @option{-fno-reciprocal-math}.
-Therefore, the G++ and GCJ drivers automatically add
-@option{-shared-libgcc} whenever you build a shared library or a main
-executable, because C++ and Java programs typically use exceptions, so
-this is the right thing to do.
+@item -ffinite-math-only
+@opindex ffinite-math-only
+Allow optimizations for floating-point arithmetic that assume
+that arguments and results are not NaNs or +-Infs.
-If, instead, you use the GCC driver to create shared libraries, you may
-find that they will not always be linked with the shared @file{libgcc}.
-If GCC finds, at its configuration time, that you have a GNU linker that
-does not support option @option{--eh-frame-hdr}, it will link the shared
-version of @file{libgcc} into shared libraries by default. Otherwise,
-it will take advantage of the linker and optimize away the linking with
-the shared version of @file{libgcc}, linking with the static version of
-libgcc by default. This allows exceptions to propagate through such
-shared libraries, without incurring relocation costs at library load
-time.
+This option is not turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions. It may, however, yield faster code for programs
+that do not require the guarantees of these specifications.
-However, if a library or main executable is supposed to throw or catch
-exceptions, you must link it using the G++ or GCJ driver, as appropriate
-for the languages used in the program, or using the option
-@option{-shared-libgcc}, such that it is linked with the shared
-@file{libgcc}.
+The default is @option{-fno-finite-math-only}.
-@item -symbolic
-@opindex symbolic
-Bind references to global symbols when building a shared object. Warn
-about any unresolved references (unless overridden by the link editor
-option @samp{-Xlinker -z -Xlinker defs}). Only a few systems support
-this option.
+@item -fno-signed-zeros
+@opindex fno-signed-zeros
+Allow optimizations for floating point arithmetic that ignore the
+signedness of zero. IEEE arithmetic specifies the behavior of
+distinct +0.0 and @minus{}0.0 values, which then prohibits simplification
+of expressions such as x+0.0 or 0.0*x (even with @option{-ffinite-math-only}).
+This option implies that the sign of a zero result isn't significant.
-@item -Xlinker @var{option}
-@opindex Xlinker
-Pass @var{option} as an option to the linker. You can use this to
-supply system-specific linker options which GCC does not know how to
-recognize.
+The default is @option{-fsigned-zeros}.
-If you want to pass an option that takes an argument, you must use
-@option{-Xlinker} twice, once for the option and once for the argument.
-For example, to pass @option{-assert definitions}, you must write
-@samp{-Xlinker -assert -Xlinker definitions}. It does not work to write
-@option{-Xlinker "-assert definitions"}, because this passes the entire
-string as a single argument, which is not what the linker expects.
+@item -fno-trapping-math
+@opindex fno-trapping-math
+Compile code assuming that floating-point operations cannot generate
+user-visible traps. These traps include division by zero, overflow,
+underflow, inexact result and invalid operation. This option requires
+that @option{-fno-signaling-nans} be in effect. Setting this option may
+allow faster code if one relies on ``non-stop'' IEEE arithmetic, for example.
-@item -Wl,@var{option}
-@opindex Wl
-Pass @var{option} as an option to the linker. If @var{option} contains
-commas, it is split into multiple options at the commas.
+This option should never be turned on by any @option{-O} option since
+it can result in incorrect output for programs which depend on
+an exact implementation of IEEE or ISO rules/specifications for
+math functions.
-@item -u @var{symbol}
-@opindex u
-Pretend the symbol @var{symbol} is undefined, to force linking of
-library modules to define it. You can use @option{-u} multiple times with
-different symbols to force loading of additional library modules.
-@end table
+The default is @option{-ftrapping-math}.
-@node Directory Options
-@section Options for Directory Search
-@cindex directory options
-@cindex options, directory search
-@cindex search path
+@item -frounding-math
+@opindex frounding-math
+Disable transformations and optimizations that assume default floating
+point rounding behavior. This is round-to-zero for all floating point
+to integer conversions, and round-to-nearest for all other arithmetic
+truncations. This option should be specified for programs that change
+the FP rounding mode dynamically, or that may be executed with a
+non-default rounding mode. This option disables constant folding of
+floating point expressions at compile-time (which may be affected by
+rounding mode) and arithmetic transformations that are unsafe in the
+presence of sign-dependent rounding modes.
+
+The default is @option{-fno-rounding-math}.
+
+This option is experimental and does not currently guarantee to
+disable all GCC optimizations that are affected by rounding mode.
+Future versions of GCC may provide finer control of this setting
+using C99's @code{FENV_ACCESS} pragma. This command line option
+will be used to specify the default state for @code{FENV_ACCESS}.
+
+@item -frtl-abstract-sequences
+@opindex frtl-abstract-sequences
+It is a size optimization method. This option is to find identical
+sequences of code, which can be turned into pseudo-procedures and
+then replace all occurrences with calls to the newly created
+subroutine. It is kind of an opposite of @option{-finline-functions}.
+This optimization runs at RTL level.
+
+@item -fsignaling-nans
+@opindex fsignaling-nans
+Compile code assuming that IEEE signaling NaNs may generate user-visible
+traps during floating-point operations. Setting this option disables
+optimizations that may change the number of exceptions visible with
+signaling NaNs. This option implies @option{-ftrapping-math}.
+
+This option causes the preprocessor macro @code{__SUPPORT_SNAN__} to
+be defined.
+
+The default is @option{-fno-signaling-nans}.
+
+This option is experimental and does not currently guarantee to
+disable all GCC optimizations that affect signaling NaN behavior.
-These options specify directories to search for header files, for
-libraries and for parts of the compiler:
+@item -fsingle-precision-constant
+@opindex fsingle-precision-constant
+Treat floating point constant as single precision constant instead of
+implicitly converting it to double precision constant.
-@table @gcctabopt
-@item -I@var{dir}
-@opindex I
-Add the directory @var{dir} to the head of the list of directories to be
-searched for header files. This can be used to override a system header
-file, substituting your own version, since these directories are
-searched before the system header file directories. However, you should
-not use this option to add directories that contain vendor-supplied
-system header files (use @option{-isystem} for that). If you use more than
-one @option{-I} option, the directories are scanned in left-to-right
-order; the standard system directories come after.
+@item -fcx-limited-range
+@opindex fcx-limited-range
+When enabled, this option states that a range reduction step is not
+needed when performing complex division. Also, there is no checking
+whether the result of a complex multiplication or division is @code{NaN
++ I*NaN}, with an attempt to rescue the situation in that case. The
+default is @option{-fno-cx-limited-range}, but is enabled by
+@option{-ffast-math}.
-If a standard system include directory, or a directory specified with
-@option{-isystem}, is also specified with @option{-I}, the @option{-I}
-option will be ignored. The directory will still be searched but as a
-system directory at its normal position in the system include chain.
-This is to ensure that GCC's procedure to fix buggy system headers and
-the ordering for the include_next directive are not inadvertantly changed.
-If you really need to change the search order for system directories,
-use the @option{-nostdinc} and/or @option{-isystem} options.
+This option controls the default setting of the ISO C99
+@code{CX_LIMITED_RANGE} pragma. Nevertheless, the option applies to
+all languages.
-@item -I-
-@opindex I-
-Any directories you specify with @option{-I} options before the @option{-I-}
-option are searched only for the case of @samp{#include "@var{file}"};
-they are not searched for @samp{#include <@var{file}>}.
+@item -fcx-fortran-rules
+@opindex fcx-fortran-rules
+Complex multiplication and division follow Fortran rules. Range
+reduction is done as part of complex division, but there is no checking
+whether the result of a complex multiplication or division is @code{NaN
++ I*NaN}, with an attempt to rescue the situation in that case.
-If additional directories are specified with @option{-I} options after
-the @option{-I-}, these directories are searched for all @samp{#include}
-directives. (Ordinarily @emph{all} @option{-I} directories are used
-this way.)
+The default is @option{-fno-cx-fortran-rules}.
-In addition, the @option{-I-} option inhibits the use of the current
-directory (where the current input file came from) as the first search
-directory for @samp{#include "@var{file}"}. There is no way to
-override this effect of @option{-I-}. With @option{-I.} you can specify
-searching the directory which was current when the compiler was
-invoked. That is not exactly the same as what the preprocessor does
-by default, but it is often satisfactory.
+@end table
-@option{-I-} does not inhibit the use of the standard system directories
-for header files. Thus, @option{-I-} and @option{-nostdinc} are
-independent.
+The following options control optimizations that may improve
+performance, but are not enabled by any @option{-O} options. This
+section includes experimental options that may produce broken code.
-@item -L@var{dir}
-@opindex L
-Add directory @var{dir} to the list of directories to be searched
-for @option{-l}.
-
-@item -B@var{prefix}
-@opindex B
-This option specifies where to find the executables, libraries,
-include files, and data files of the compiler itself.
+@table @gcctabopt
+@item -fbranch-probabilities
+@opindex fbranch-probabilities
+After running a program compiled with @option{-fprofile-arcs}
+(@pxref{Debugging Options,, Options for Debugging Your Program or
+@command{gcc}}), you can compile it a second time using
+@option{-fbranch-probabilities}, to improve optimizations based on
+the number of times each branch was taken. When the program
+compiled with @option{-fprofile-arcs} exits it saves arc execution
+counts to a file called @file{@var{sourcename}.gcda} for each source
+file. The information in this data file is very dependent on the
+structure of the generated code, so you must use the same source code
+and the same optimization options for both compilations.
-The compiler driver program runs one or more of the subprograms
-@file{cpp}, @file{cc1}, @file{as} and @file{ld}. It tries
-@var{prefix} as a prefix for each program it tries to run, both with and
-without @samp{@var{machine}/@var{version}/} (@pxref{Target Options}).
+With @option{-fbranch-probabilities}, GCC puts a
+@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}.
+These can be used to improve optimization. Currently, they are only
+used in one place: in @file{reorg.c}, instead of guessing which path a
+branch is mostly to take, the @samp{REG_BR_PROB} values are used to
+exactly determine which path is taken more often.
-For each subprogram to be run, the compiler driver first tries the
-@option{-B} prefix, if any. If that name is not found, or if @option{-B}
-was not specified, the driver tries two standard prefixes, which are
-@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc-lib/}. If neither of
-those results in a file name that is found, the unmodified program
-name is searched for using the directories specified in your
-@env{PATH} environment variable.
+@item -fprofile-values
+@opindex fprofile-values
+If combined with @option{-fprofile-arcs}, it adds code so that some
+data about values of expressions in the program is gathered.
-The compiler will check to see if the path provided by the @option{-B}
-refers to a directory, and if necessary it will add a directory
-separator character at the end of the path.
+With @option{-fbranch-probabilities}, it reads back the data gathered
+from profiling values of expressions and adds @samp{REG_VALUE_PROFILE}
+notes to instructions for their later usage in optimizations.
-@option{-B} prefixes that effectively specify directory names also apply
-to libraries in the linker, because the compiler translates these
-options into @option{-L} options for the linker. They also apply to
-includes files in the preprocessor, because the compiler translates these
-options into @option{-isystem} options for the preprocessor. In this case,
-the compiler appends @samp{include} to the prefix.
+Enabled with @option{-fprofile-generate} and @option{-fprofile-use}.
-The run-time support file @file{libgcc.a} can also be searched for using
-the @option{-B} prefix, if needed. If it is not found there, the two
-standard prefixes above are tried, and that is all. The file is left
-out of the link if it is not found by those means.
+@item -fvpt
+@opindex fvpt
+If combined with @option{-fprofile-arcs}, it instructs the compiler to add
+a code to gather information about values of expressions.
-Another way to specify a prefix much like the @option{-B} prefix is to use
-the environment variable @env{GCC_EXEC_PREFIX}. @xref{Environment
-Variables}.
+With @option{-fbranch-probabilities}, it reads back the data gathered
+and actually performs the optimizations based on them.
+Currently the optimizations include specialization of division operation
+using the knowledge about the value of the denominator.
-As a special kludge, if the path provided by @option{-B} is
-@file{[dir/]stage@var{N}/}, where @var{N} is a number in the range 0 to
-9, then it will be replaced by @file{[dir/]include}. This is to help
-with boot-strapping the compiler.
+@item -frename-registers
+@opindex frename-registers
+Attempt to avoid false dependencies in scheduled code by making use
+of registers left over after register allocation. This optimization
+will most benefit processors with lots of registers. Depending on the
+debug information format adopted by the target, however, it can
+make debugging impossible, since variables will no longer stay in
+a ``home register''.
-@item -specs=@var{file}
-@opindex specs
-Process @var{file} after the compiler reads in the standard @file{specs}
-file, in order to override the defaults that the @file{gcc} driver
-program uses when determining what switches to pass to @file{cc1},
-@file{cc1plus}, @file{as}, @file{ld}, etc. More than one
-@option{-specs=@var{file}} can be specified on the command line, and they
-are processed in order, from left to right.
-@end table
+Enabled by default with @option{-funroll-loops}.
-@c man end
+@item -ftracer
+@opindex ftracer
+Perform tail duplication to enlarge superblock size. This transformation
+simplifies the control flow of the function allowing other optimizations to do
+better job.
-@node Spec Files
-@section Specifying subprocesses and the switches to pass to them
-@cindex Spec Files
-@command{gcc} is a driver program. It performs its job by invoking a
-sequence of other programs to do the work of compiling, assembling and
-linking. GCC interprets its command-line parameters and uses these to
-deduce which programs it should invoke, and which command-line options
-it ought to place on their command lines. This behavior is controlled
-by @dfn{spec strings}. In most cases there is one spec string for each
-program that GCC can invoke, but a few programs have multiple spec
-strings to control their behavior. The spec strings built into GCC can
-be overridden by using the @option{-specs=} command-line switch to specify
-a spec file.
+Enabled with @option{-fprofile-use}.
-@dfn{Spec files} are plaintext files that are used to construct spec
-strings. They consist of a sequence of directives separated by blank
-lines. The type of directive is determined by the first non-whitespace
-character on the line and it can be one of the following:
+@item -funroll-loops
+@opindex funroll-loops
+Unroll loops whose number of iterations can be determined at compile time or
+upon entry to the loop. @option{-funroll-loops} implies
+@option{-frerun-cse-after-loop}, @option{-fweb} and @option{-frename-registers}.
+It also turns on complete loop peeling (i.e.@: complete removal of loops with
+small constant number of iterations). This option makes code larger, and may
+or may not make it run faster.
-@table @code
-@item %@var{command}
-Issues a @var{command} to the spec file processor. The commands that can
-appear here are:
+Enabled with @option{-fprofile-use}.
-@table @code
-@item %include <@var{file}>
-@cindex %include
-Search for @var{file} and insert its text at the current point in the
-specs file.
+@item -funroll-all-loops
+@opindex funroll-all-loops
+Unroll all loops, even if their number of iterations is uncertain when
+the loop is entered. This usually makes programs run more slowly.
+@option{-funroll-all-loops} implies the same options as
+@option{-funroll-loops}.
-@item %include_noerr <@var{file}>
-@cindex %include_noerr
-Just like @samp{%include}, but do not generate an error message if the include
-file cannot be found.
+@item -fpeel-loops
+@opindex fpeel-loops
+Peels the loops for that there is enough information that they do not
+roll much (from profile feedback). It also turns on complete loop peeling
+(i.e.@: complete removal of loops with small constant number of iterations).
-@item %rename @var{old_name} @var{new_name}
-@cindex %rename
-Rename the spec string @var{old_name} to @var{new_name}.
+Enabled with @option{-fprofile-use}.
-@end table
+@item -fmove-loop-invariants
+@opindex fmove-loop-invariants
+Enables the loop invariant motion pass in the RTL loop optimizer. Enabled
+at level @option{-O1}
-@item *[@var{spec_name}]:
-This tells the compiler to create, override or delete the named spec
-string. All lines after this directive up to the next directive or
-blank line are considered to be the text for the spec string. If this
-results in an empty string then the spec will be deleted. (Or, if the
-spec did not exist, then nothing will happened.) Otherwise, if the spec
-does not currently exist a new spec will be created. If the spec does
-exist then its contents will be overridden by the text of this
-directive, unless the first character of that text is the @samp{+}
-character, in which case the text will be appended to the spec.
+@item -funswitch-loops
+@opindex funswitch-loops
+Move branches with loop invariant conditions out of the loop, with duplicates
+of the loop on both branches (modified according to result of the condition).
-@item [@var{suffix}]:
-Creates a new @samp{[@var{suffix}] spec} pair. All lines after this directive
-and up to the next directive or blank line are considered to make up the
-spec string for the indicated suffix. When the compiler encounters an
-input file with the named suffix, it will processes the spec string in
-order to work out how to compile that file. For example:
+@item -ffunction-sections
+@itemx -fdata-sections
+@opindex ffunction-sections
+@opindex fdata-sections
+Place each function or data item into its own section in the output
+file if the target supports arbitrary sections. The name of the
+function or the name of the data item determines the section's name
+in the output file.
-@smallexample
-.ZZ:
-z-compile -input %i
-@end smallexample
+Use these options on systems where the linker can perform optimizations
+to improve locality of reference in the instruction space. Most systems
+using the ELF object format and SPARC processors running Solaris 2 have
+linkers with such optimizations. AIX may have these optimizations in
+the future.
-This says that any input file whose name ends in @samp{.ZZ} should be
-passed to the program @samp{z-compile}, which should be invoked with the
-command-line switch @option{-input} and with the result of performing the
-@samp{%i} substitution. (See below.)
+Only use these options when there are significant benefits from doing
+so. When you specify these options, the assembler and linker will
+create larger object and executable files and will also be slower.
+You will not be able to use @code{gprof} on all systems if you
+specify this option and you may have problems with debugging if
+you specify both this option and @option{-g}.
-As an alternative to providing a spec string, the text that follows a
-suffix directive can be one of the following:
+@item -fbranch-target-load-optimize
+@opindex fbranch-target-load-optimize
+Perform branch target register load optimization before prologue / epilogue
+threading.
+The use of target registers can typically be exposed only during reload,
+thus hoisting loads out of loops and doing inter-block scheduling needs
+a separate optimization pass.
+
+@item -fbranch-target-load-optimize2
+@opindex fbranch-target-load-optimize2
+Perform branch target register load optimization after prologue / epilogue
+threading.
+
+@item -fbtr-bb-exclusive
+@opindex fbtr-bb-exclusive
+When performing branch target register load optimization, don't reuse
+branch target registers in within any basic block.
+
+@item -fstack-protector
+@opindex fstack-protector
+Emit extra code to check for buffer overflows, such as stack smashing
+attacks. This is done by adding a guard variable to functions with
+vulnerable objects. This includes functions that call alloca, and
+functions with buffers larger than 8 bytes. The guards are initialized
+when a function is entered and then checked when the function exits.
+If a guard check fails, an error message is printed and the program exits.
+
+@item -fstack-protector-all
+@opindex fstack-protector-all
+Like @option{-fstack-protector} except that all functions are protected.
+
+@item -fsection-anchors
+@opindex fsection-anchors
+Try to reduce the number of symbolic address calculations by using
+shared ``anchor'' symbols to address nearby objects. This transformation
+can help to reduce the number of GOT entries and GOT accesses on some
+targets.
-@table @code
-@item @@@var{language}
-This says that the suffix is an alias for a known @var{language}. This is
-similar to using the @option{-x} command-line switch to GCC to specify a
-language explicitly. For example:
+For example, the implementation of the following function @code{foo}:
@smallexample
-.ZZ:
-@@c++
+static int a, b, c;
+int foo (void) @{ return a + b + c; @}
@end smallexample
-Says that .ZZ files are, in fact, C++ source files.
-
-@item #@var{name}
-This causes an error messages saying:
+would usually calculate the addresses of all three variables, but if you
+compile it with @option{-fsection-anchors}, it will access the variables
+from a common anchor point instead. The effect is similar to the
+following pseudocode (which isn't valid C):
@smallexample
-@var{name} compiler not installed on this system.
+int foo (void)
+@{
+ register int *xr = &x;
+ return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
+@}
@end smallexample
-@end table
-GCC already has an extensive list of suffixes built into it.
-This directive will add an entry to the end of the list of suffixes, but
-since the list is searched from the end backwards, it is effectively
-possible to override earlier entries using this technique.
+Not all targets support this option.
-@end table
+@item --param @var{name}=@var{value}
+@opindex param
+In some places, GCC uses various constants to control the amount of
+optimization that is done. For example, GCC will not inline functions
+that contain more that a certain number of instructions. You can
+control some of these constants on the command-line using the
+@option{--param} option.
-GCC has the following spec strings built into it. Spec files can
-override these strings or create their own. Note that individual
-targets can also add their own spec strings to this list.
+The names of specific parameters, and the meaning of the values, are
+tied to the internals of the compiler, and are subject to change
+without notice in future releases.
-@smallexample
-asm Options to pass to the assembler
-asm_final Options to pass to the assembler post-processor
-cpp Options to pass to the C preprocessor
-cc1 Options to pass to the C compiler
-cc1plus Options to pass to the C++ compiler
-endfile Object files to include at the end of the link
-link Options to pass to the linker
-lib Libraries to include on the command line to the linker
-libgcc Decides which GCC support library to pass to the linker
-linker Sets the name of the linker
-predefines Defines to be passed to the C preprocessor
-signed_char Defines to pass to CPP to say whether @code{char} is signed
- by default
-startfile Object files to include at the start of the link
-@end smallexample
+In each case, the @var{value} is an integer. The allowable choices for
+@var{name} are given in the following table:
-Here is a small example of a spec file:
+@table @gcctabopt
+@item sra-max-structure-size
+The maximum structure size, in bytes, at which the scalar replacement
+of aggregates (SRA) optimization will perform block copies. The
+default value, 0, implies that GCC will select the most appropriate
+size itself.
+
+@item sra-field-structure-ratio
+The threshold ratio (as a percentage) between instantiated fields and
+the complete structure size. We say that if the ratio of the number
+of bytes in instantiated fields to the number of bytes in the complete
+structure exceeds this parameter, then block copies are not used. The
+default is 75.
+
+@item struct-reorg-cold-struct-ratio
+The threshold ratio (as a percentage) between a structure frequency
+and the frequency of the hottest structure in the program. This parameter
+is used by struct-reorg optimization enabled by @option{-fipa-struct-reorg}.
+We say that if the ratio of a structure frequency, calculated by profiling,
+to the hottest structure frequency in the program is less than this
+parameter, then structure reorganization is not applied to this structure.
+The default is 10.
+
+@item predictable-branch-cost-outcome
+When branch is predicted to be taken with probability lower than this threshold
+(in percent), then it is considered well predictable. The default is 10.
+
+@item max-crossjump-edges
+The maximum number of incoming edges to consider for crossjumping.
+The algorithm used by @option{-fcrossjumping} is @math{O(N^2)} in
+the number of edges incoming to each block. Increasing values mean
+more aggressive optimization, making the compile time increase with
+probably small improvement in executable size.
+
+@item min-crossjump-insns
+The minimum number of instructions which must be matched at the end
+of two blocks before crossjumping will be performed on them. This
+value is ignored in the case where all instructions in the block being
+crossjumped from are matched. The default value is 5.
+
+@item max-grow-copy-bb-insns
+The maximum code size expansion factor when copying basic blocks
+instead of jumping. The expansion is relative to a jump instruction.
+The default value is 8.
+
+@item max-goto-duplication-insns
+The maximum number of instructions to duplicate to a block that jumps
+to a computed goto. To avoid @math{O(N^2)} behavior in a number of
+passes, GCC factors computed gotos early in the compilation process,
+and unfactors them as late as possible. Only computed jumps at the
+end of a basic blocks with no more than max-goto-duplication-insns are
+unfactored. The default value is 8.
-@smallexample
-%rename lib old_lib
+@item max-delay-slot-insn-search
+The maximum number of instructions to consider when looking for an
+instruction to fill a delay slot. If more than this arbitrary number of
+instructions is searched, the time savings from filling the delay slot
+will be minimal so stop searching. Increasing values mean more
+aggressive optimization, making the compile time increase with probably
+small improvement in executable run time.
-*lib:
---start-group -lgcc -lc -leval1 --end-group %(old_lib)
-@end smallexample
+@item max-delay-slot-live-search
+When trying to fill delay slots, the maximum number of instructions to
+consider when searching for a block with valid live register
+information. Increasing this arbitrarily chosen value means more
+aggressive optimization, increasing the compile time. This parameter
+should be removed when the delay slot code is rewritten to maintain the
+control-flow graph.
-This example renames the spec called @samp{lib} to @samp{old_lib} and
-then overrides the previous definition of @samp{lib} with a new one.
-The new definition adds in some extra command-line options before
-including the text of the old definition.
+@item max-gcse-memory
+The approximate maximum amount of memory that will be allocated in
+order to perform the global common subexpression elimination
+optimization. If more memory than specified is required, the
+optimization will not be done.
-@dfn{Spec strings} are a list of command-line options to be passed to their
-corresponding program. In addition, the spec strings can contain
-@samp{%}-prefixed sequences to substitute variable text or to
-conditionally insert text into the command line. Using these constructs
-it is possible to generate quite complex command lines.
+@item max-gcse-passes
+The maximum number of passes of GCSE to run. The default is 1.
-Here is a table of all defined @samp{%}-sequences for spec
-strings. Note that spaces are not generated automatically around the
-results of expanding these sequences. Therefore you can concatenate them
-together or combine them with constant text in a single argument.
+@item max-pending-list-length
+The maximum number of pending dependencies scheduling will allow
+before flushing the current state and starting over. Large functions
+with few branches or calls can create excessively large lists which
+needlessly consume memory and resources.
-@table @code
-@item %%
-Substitute one @samp{%} into the program name or argument.
+@item max-inline-insns-single
+Several parameters control the tree inliner used in gcc.
+This number sets the maximum number of instructions (counted in GCC's
+internal representation) in a single function that the tree inliner
+will consider for inlining. This only affects functions declared
+inline and methods implemented in a class declaration (C++).
+The default value is 450.
+
+@item max-inline-insns-auto
+When you use @option{-finline-functions} (included in @option{-O3}),
+a lot of functions that would otherwise not be considered for inlining
+by the compiler will be investigated. To those functions, a different
+(more restrictive) limit compared to functions declared inline can
+be applied.
+The default value is 90.
+
+@item large-function-insns
+The limit specifying really large functions. For functions larger than this
+limit after inlining, inlining is constrained by
+@option{--param large-function-growth}. This parameter is useful primarily
+to avoid extreme compilation time caused by non-linear algorithms used by the
+backend.
+The default value is 2700.
+
+@item large-function-growth
+Specifies maximal growth of large function caused by inlining in percents.
+The default value is 100 which limits large function growth to 2.0 times
+the original size.
+
+@item large-unit-insns
+The limit specifying large translation unit. Growth caused by inlining of
+units larger than this limit is limited by @option{--param inline-unit-growth}.
+For small units this might be too tight (consider unit consisting of function A
+that is inline and B that just calls A three time. If B is small relative to
+A, the growth of unit is 300\% and yet such inlining is very sane. For very
+large units consisting of small inlineable functions however the overall unit
+growth limit is needed to avoid exponential explosion of code size. Thus for
+smaller units, the size is increased to @option{--param large-unit-insns}
+before applying @option{--param inline-unit-growth}. The default is 10000
+
+@item inline-unit-growth
+Specifies maximal overall growth of the compilation unit caused by inlining.
+The default value is 30 which limits unit growth to 1.3 times the original
+size.
-@item %i
-Substitute the name of the input file being processed.
+@item ipcp-unit-growth
+Specifies maximal overall growth of the compilation unit caused by
+interprocedural constant propagation. The default value is 10 which limits
+unit growth to 1.1 times the original size.
+
+@item large-stack-frame
+The limit specifying large stack frames. While inlining the algorithm is trying
+to not grow past this limit too much. Default value is 256 bytes.
+
+@item large-stack-frame-growth
+Specifies maximal growth of large stack frames caused by inlining in percents.
+The default value is 1000 which limits large stack frame growth to 11 times
+the original size.
+
+@item max-inline-insns-recursive
+@itemx max-inline-insns-recursive-auto
+Specifies maximum number of instructions out-of-line copy of self recursive inline
+function can grow into by performing recursive inlining.
+
+For functions declared inline @option{--param max-inline-insns-recursive} is
+taken into account. For function not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled and @option{--param max-inline-insns-recursive-auto} is used. The
+default value is 450.
+
+@item max-inline-recursive-depth
+@itemx max-inline-recursive-depth-auto
+Specifies maximum recursion depth used by the recursive inlining.
+
+For functions declared inline @option{--param max-inline-recursive-depth} is
+taken into account. For function not declared inline, recursive inlining
+happens only when @option{-finline-functions} (included in @option{-O3}) is
+enabled and @option{--param max-inline-recursive-depth-auto} is used. The
+default value is 8.
+
+@item min-inline-recursive-probability
+Recursive inlining is profitable only for function having deep recursion
+in average and can hurt for function having little recursion depth by
+increasing the prologue size or complexity of function body to other
+optimizers.
+
+When profile feedback is available (see @option{-fprofile-generate}) the actual
+recursion depth can be guessed from probability that function will recurse via
+given call expression. This parameter limits inlining only to call expression
+whose probability exceeds given threshold (in percents). The default value is
+10.
+
+@item inline-call-cost
+Specify cost of call instruction relative to simple arithmetics operations
+(having cost of 1). Increasing this cost disqualifies inlining of non-leaf
+functions and at the same time increases size of leaf function that is believed to
+reduce function size by being inlined. In effect it increases amount of
+inlining for code having large abstraction penalty (many functions that just
+pass the arguments to other functions) and decrease inlining for code with low
+abstraction penalty. The default value is 12.
+
+@item min-vect-loop-bound
+The minimum number of iterations under which a loop will not get vectorized
+when @option{-ftree-vectorize} is used. The number of iterations after
+vectorization needs to be greater than the value specified by this option
+to allow vectorization. The default value is 0.
+
+@item max-unrolled-insns
+The maximum number of instructions that a loop should have if that loop
+is unrolled, and if the loop is unrolled, it determines how many times
+the loop code is unrolled.
+
+@item max-average-unrolled-insns
+The maximum number of instructions biased by probabilities of their execution
+that a loop should have if that loop is unrolled, and if the loop is unrolled,
+it determines how many times the loop code is unrolled.
+
+@item max-unroll-times
+The maximum number of unrollings of a single loop.
+
+@item max-peeled-insns
+The maximum number of instructions that a loop should have if that loop
+is peeled, and if the loop is peeled, it determines how many times
+the loop code is peeled.
+
+@item max-peel-times
+The maximum number of peelings of a single loop.
+
+@item max-completely-peeled-insns
+The maximum number of insns of a completely peeled loop.
+
+@item max-completely-peel-times
+The maximum number of iterations of a loop to be suitable for complete peeling.
+
+@item max-unswitch-insns
+The maximum number of insns of an unswitched loop.
+
+@item max-unswitch-level
+The maximum number of branches unswitched in a single loop.
+
+@item lim-expensive
+The minimum cost of an expensive expression in the loop invariant motion.
+
+@item iv-consider-all-candidates-bound
+Bound on number of candidates for induction variables below that
+all candidates are considered for each use in induction variable
+optimizations. Only the most relevant candidates are considered
+if there are more candidates, to avoid quadratic time complexity.
+
+@item iv-max-considered-uses
+The induction variable optimizations give up on loops that contain more
+induction variable uses.
+
+@item iv-always-prune-cand-set-bound
+If number of candidates in the set is smaller than this value,
+we always try to remove unnecessary ivs from the set during its
+optimization when a new iv is added to the set.
+
+@item scev-max-expr-size
+Bound on size of expressions used in the scalar evolutions analyzer.
+Large expressions slow the analyzer.
+
+@item omega-max-vars
+The maximum number of variables in an Omega constraint system.
+The default value is 128.
+
+@item omega-max-geqs
+The maximum number of inequalities in an Omega constraint system.
+The default value is 256.
-@item %b
-Substitute the basename of the input file being processed.
-This is the substring up to (and not including) the last period
-and not including the directory.
-
-@item %B
-This is the same as @samp{%b}, but include the file suffix (text after
-the last period).
+@item omega-max-eqs
+The maximum number of equalities in an Omega constraint system.
+The default value is 128.
-@item %d
-Marks the argument containing or following the @samp{%d} as a
-temporary file name, so that that file will be deleted if GCC exits
-successfully. Unlike @samp{%g}, this contributes no text to the
-argument.
+@item omega-max-wild-cards
+The maximum number of wildcard variables that the Omega solver will
+be able to insert. The default value is 18.
-@item %g@var{suffix}
-Substitute a file name that has suffix @var{suffix} and is chosen
-once per compilation, and mark the argument in the same way as
-@samp{%d}. To reduce exposure to denial-of-service attacks, the file
-name is now chosen in a way that is hard to predict even when previously
-chosen file names are known. For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
-might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}. @var{suffix} matches
-the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
-treated exactly as if @samp{%O} had been preprocessed. Previously, @samp{%g}
-was simply substituted with a file name chosen once per compilation,
-without regard to any appended suffix (which was therefore treated
-just like ordinary text), making such attacks more likely to succeed.
+@item omega-hash-table-size
+The size of the hash table in the Omega solver. The default value is
+550.
-@item %u@var{suffix}
-Like @samp{%g}, but generates a new temporary file name even if
-@samp{%u@var{suffix}} was already seen.
+@item omega-max-keys
+The maximal number of keys used by the Omega solver. The default
+value is 500.
-@item %U@var{suffix}
-Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
-new one if there is no such last file name. In the absence of any
-@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
-the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
-would involve the generation of two distinct file names, one
-for each @samp{%g.s} and another for each @samp{%U.s}. Previously, @samp{%U} was
-simply substituted with a file name chosen for the previous @samp{%u},
-without regard to any appended suffix.
+@item omega-eliminate-redundant-constraints
+When set to 1, use expensive methods to eliminate all redundant
+constraints. The default value is 0.
-@item %j@var{SUFFIX}
-Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
-writable, and if save-temps is off; otherwise, substitute the name
-of a temporary file, just like @samp{%u}. This temporary file is not
-meant for communication between processes, but rather as a junk
-disposal mechanism.
+@item vect-max-version-for-alignment-checks
+The maximum number of runtime checks that can be performed when
+doing loop versioning for alignment in the vectorizer. See option
+ftree-vect-loop-version for more information.
-@item %.@var{SUFFIX}
-Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
-when it is subsequently output with @samp{%*}. @var{SUFFIX} is
-terminated by the next space or %.
+@item vect-max-version-for-alias-checks
+The maximum number of runtime checks that can be performed when
+doing loop versioning for alias in the vectorizer. See option
+ftree-vect-loop-version for more information.
-@item %w
-Marks the argument containing or following the @samp{%w} as the
-designated output file of this compilation. This puts the argument
-into the sequence of arguments that @samp{%o} will substitute later.
+@item max-iterations-to-track
-@item %o
-Substitutes the names of all the output files, with spaces
-automatically placed around them. You should write spaces
-around the @samp{%o} as well or the results are undefined.
-@samp{%o} is for use in the specs for running the linker.
-Input files whose names have no recognized suffix are not compiled
-at all, but they are included among the output files, so they will
-be linked.
+The maximum number of iterations of a loop the brute force algorithm
+for analysis of # of iterations of the loop tries to evaluate.
-@item %O
-Substitutes the suffix for object files. Note that this is
-handled specially when it immediately follows @samp{%g, %u, or %U},
-because of the need for those to form complete file names. The
-handling is such that @samp{%O} is treated exactly as if it had already
-been substituted, except that @samp{%g, %u, and %U} do not currently
-support additional @var{suffix} characters following @samp{%O} as they would
-following, for example, @samp{.o}.
+@item hot-bb-count-fraction
+Select fraction of the maximal count of repetitions of basic block in program
+given basic block needs to have to be considered hot.
-@item %p
-Substitutes the standard macro predefinitions for the
-current target machine. Use this when running @code{cpp}.
+@item hot-bb-frequency-fraction
+Select fraction of the maximal frequency of executions of basic block in
+function given basic block needs to have to be considered hot
-@item %P
-Like @samp{%p}, but puts @samp{__} before and after the name of each
-predefined macro, except for macros that start with @samp{__} or with
-@samp{_@var{L}}, where @var{L} is an uppercase letter. This is for ISO
-C@.
+@item max-predicted-iterations
+The maximum number of loop iterations we predict statically. This is useful
+in cases where function contain single loop with known bound and other loop
+with unknown. We predict the known number of iterations correctly, while
+the unknown number of iterations average to roughly 10. This means that the
+loop without bounds would appear artificially cold relative to the other one.
-@item %I
-Substitute a @option{-iprefix} option made from @env{GCC_EXEC_PREFIX}.
+@item align-threshold
-@item %s
-Current argument is the name of a library or startup file of some sort.
-Search for that file in a standard list of directories and substitute
-the full name found.
+Select fraction of the maximal frequency of executions of basic block in
+function given basic block will get aligned.
-@item %e@var{str}
-Print @var{str} as an error message. @var{str} is terminated by a newline.
-Use this when inconsistent options are detected.
+@item align-loop-iterations
-@item %|
-Output @samp{-} if the input for the current command is coming from a pipe.
+A loop expected to iterate at lest the selected number of iterations will get
+aligned.
-@item %(@var{name})
-Substitute the contents of spec string @var{name} at this point.
+@item tracer-dynamic-coverage
+@itemx tracer-dynamic-coverage-feedback
+
+This value is used to limit superblock formation once the given percentage of
+executed instructions is covered. This limits unnecessary code size
+expansion.
+
+The @option{tracer-dynamic-coverage-feedback} is used only when profile
+feedback is available. The real profiles (as opposed to statically estimated
+ones) are much less balanced allowing the threshold to be larger value.
+
+@item tracer-max-code-growth
+Stop tail duplication once code growth has reached given percentage. This is
+rather hokey argument, as most of the duplicates will be eliminated later in
+cross jumping, so it may be set to much higher values than is the desired code
+growth.
+
+@item tracer-min-branch-ratio
+
+Stop reverse growth when the reverse probability of best edge is less than this
+threshold (in percent).
+
+@item tracer-min-branch-ratio
+@itemx tracer-min-branch-ratio-feedback
+
+Stop forward growth if the best edge do have probability lower than this
+threshold.
+
+Similarly to @option{tracer-dynamic-coverage} two values are present, one for
+compilation for profile feedback and one for compilation without. The value
+for compilation with profile feedback needs to be more conservative (higher) in
+order to make tracer effective.
+
+@item max-cse-path-length
+
+Maximum number of basic blocks on path that cse considers. The default is 10.
+
+@item max-cse-insns
+The maximum instructions CSE process before flushing. The default is 1000.
+
+@item max-aliased-vops
+
+Maximum number of virtual operands per function allowed to represent
+aliases before triggering the alias partitioning heuristic. Alias
+partitioning reduces compile times and memory consumption needed for
+aliasing at the expense of precision loss in alias information. The
+default value for this parameter is 100 for -O1, 500 for -O2 and 1000
+for -O3.
+
+Notice that if a function contains more memory statements than the
+value of this parameter, it is not really possible to achieve this
+reduction. In this case, the compiler will use the number of memory
+statements as the value for @option{max-aliased-vops}.
+
+@item avg-aliased-vops
+
+Average number of virtual operands per statement allowed to represent
+aliases before triggering the alias partitioning heuristic. This
+works in conjunction with @option{max-aliased-vops}. If a function
+contains more than @option{max-aliased-vops} virtual operators, then
+memory symbols will be grouped into memory partitions until either the
+total number of virtual operators is below @option{max-aliased-vops}
+or the average number of virtual operators per memory statement is
+below @option{avg-aliased-vops}. The default value for this parameter
+is 1 for -O1 and -O2, and 3 for -O3.
+
+@item ggc-min-expand
+
+GCC uses a garbage collector to manage its own memory allocation. This
+parameter specifies the minimum percentage by which the garbage
+collector's heap should be allowed to expand between collections.
+Tuning this may improve compilation speed; it has no effect on code
+generation.
+
+The default is 30% + 70% * (RAM/1GB) with an upper bound of 100% when
+RAM >= 1GB@. If @code{getrlimit} is available, the notion of "RAM" is
+the smallest of actual RAM and @code{RLIMIT_DATA} or @code{RLIMIT_AS}. If
+GCC is not able to calculate RAM on a particular platform, the lower
+bound of 30% is used. Setting this parameter and
+@option{ggc-min-heapsize} to zero causes a full collection to occur at
+every opportunity. This is extremely slow, but can be useful for
+debugging.
+
+@item ggc-min-heapsize
+
+Minimum size of the garbage collector's heap before it begins bothering
+to collect garbage. The first collection occurs after the heap expands
+by @option{ggc-min-expand}% beyond @option{ggc-min-heapsize}. Again,
+tuning this may improve compilation speed, and has no effect on code
+generation.
+
+The default is the smaller of RAM/8, RLIMIT_RSS, or a limit which
+tries to ensure that RLIMIT_DATA or RLIMIT_AS are not exceeded, but
+with a lower bound of 4096 (four megabytes) and an upper bound of
+131072 (128 megabytes). If GCC is not able to calculate RAM on a
+particular platform, the lower bound is used. Setting this parameter
+very large effectively disables garbage collection. Setting this
+parameter and @option{ggc-min-expand} to zero causes a full collection
+to occur at every opportunity.
+
+@item max-reload-search-insns
+The maximum number of instruction reload should look backward for equivalent
+register. Increasing values mean more aggressive optimization, making the
+compile time increase with probably slightly better performance. The default
+value is 100.
+
+@item max-cselib-memory-locations
+The maximum number of memory locations cselib should take into account.
+Increasing values mean more aggressive optimization, making the compile time
+increase with probably slightly better performance. The default value is 500.
+
+@item reorder-blocks-duplicate
+@itemx reorder-blocks-duplicate-feedback
+
+Used by basic block reordering pass to decide whether to use unconditional
+branch or duplicate the code on its destination. Code is duplicated when its
+estimated size is smaller than this value multiplied by the estimated size of
+unconditional jump in the hot spots of the program.
+
+The @option{reorder-block-duplicate-feedback} is used only when profile
+feedback is available and may be set to higher values than
+@option{reorder-block-duplicate} since information about the hot spots is more
+accurate.
+
+@item max-sched-ready-insns
+The maximum number of instructions ready to be issued the scheduler should
+consider at any given time during the first scheduling pass. Increasing
+values mean more thorough searches, making the compilation time increase
+with probably little benefit. The default value is 100.
+
+@item max-sched-region-blocks
+The maximum number of blocks in a region to be considered for
+interblock scheduling. The default value is 10.
+
+@item max-pipeline-region-blocks
+The maximum number of blocks in a region to be considered for
+pipelining in the selective scheduler. The default value is 15.
+
+@item max-sched-region-insns
+The maximum number of insns in a region to be considered for
+interblock scheduling. The default value is 100.
+
+@item max-pipeline-region-insns
+The maximum number of insns in a region to be considered for
+pipelining in the selective scheduler. The default value is 200.
+
+@item min-spec-prob
+The minimum probability (in percents) of reaching a source block
+for interblock speculative scheduling. The default value is 40.
+
+@item max-sched-extend-regions-iters
+The maximum number of iterations through CFG to extend regions.
+0 - disable region extension,
+N - do at most N iterations.
+The default value is 0.
+
+@item max-sched-insn-conflict-delay
+The maximum conflict delay for an insn to be considered for speculative motion.
+The default value is 3.
+
+@item sched-spec-prob-cutoff
+The minimal probability of speculation success (in percents), so that
+speculative insn will be scheduled.
+The default value is 40.
+
+@item sched-mem-true-dep-cost
+Minimal distance (in CPU cycles) between store and load targeting same
+memory locations. The default value is 1.
+
+@item selsched-max-lookahead
+The maximum size of the lookahead window of selective scheduling. It is a
+depth of search for available instructions.
+The default value is 50.
+
+@item selsched-max-sched-times
+The maximum number of times that an instruction will be scheduled during
+selective scheduling. This is the limit on the number of iterations
+through which the instruction may be pipelined. The default value is 2.
+
+@item selsched-max-insns-to-rename
+The maximum number of best instructions in the ready list that are considered
+for renaming in the selective scheduler. The default value is 2.
+
+@item max-last-value-rtl
+The maximum size measured as number of RTLs that can be recorded in an expression
+in combiner for a pseudo register as last known value of that register. The default
+is 10000.
+
+@item integer-share-limit
+Small integer constants can use a shared data structure, reducing the
+compiler's memory usage and increasing its speed. This sets the maximum
+value of a shared integer constant. The default value is 256.
+
+@item min-virtual-mappings
+Specifies the minimum number of virtual mappings in the incremental
+SSA updater that should be registered to trigger the virtual mappings
+heuristic defined by virtual-mappings-ratio. The default value is
+100.
+
+@item virtual-mappings-ratio
+If the number of virtual mappings is virtual-mappings-ratio bigger
+than the number of virtual symbols to be updated, then the incremental
+SSA updater switches to a full update for those symbols. The default
+ratio is 3.
+
+@item ssp-buffer-size
+The minimum size of buffers (i.e.@: arrays) that will receive stack smashing
+protection when @option{-fstack-protection} is used.
+
+@item max-jump-thread-duplication-stmts
+Maximum number of statements allowed in a block that needs to be
+duplicated when threading jumps.
+
+@item max-fields-for-field-sensitive
+Maximum number of fields in a structure we will treat in
+a field sensitive manner during pointer analysis. The default is zero
+for -O0, and -O1 and 100 for -Os, -O2, and -O3.
+
+@item prefetch-latency
+Estimate on average number of instructions that are executed before
+prefetch finishes. The distance we prefetch ahead is proportional
+to this constant. Increasing this number may also lead to less
+streams being prefetched (see @option{simultaneous-prefetches}).
+
+@item simultaneous-prefetches
+Maximum number of prefetches that can run at the same time.
+
+@item l1-cache-line-size
+The size of cache line in L1 cache, in bytes.
+
+@item l1-cache-size
+The size of L1 cache, in kilobytes.
+
+@item l2-cache-size
+The size of L2 cache, in kilobytes.
+
+@item use-canonical-types
+Whether the compiler should use the ``canonical'' type system. By
+default, this should always be 1, which uses a more efficient internal
+mechanism for comparing types in C++ and Objective-C++. However, if
+bugs in the canonical type system are causing compilation failures,
+set this value to 0 to disable canonical types.
+
+@item switch-conversion-max-branch-ratio
+Switch initialization conversion will refuse to create arrays that are
+bigger than @option{switch-conversion-max-branch-ratio} times the number of
+branches in the switch.
+
+@item max-partial-antic-length
+Maximum length of the partial antic set computed during the tree
+partial redundancy elimination optimization (@option{-ftree-pre}) when
+optimizing at @option{-O3} and above. For some sorts of source code
+the enhanced partial redundancy elimination optimization can run away,
+consuming all of the memory available on the host machine. This
+parameter sets a limit on the length of the sets that are computed,
+which prevents the runaway behavior. Setting a value of 0 for
+this parameter will allow an unlimited set length.
+
+@item sccvn-max-scc-size
+Maximum size of a strongly connected component (SCC) during SCCVN
+processing. If this limit is hit, SCCVN processing for the whole
+function will not be done and optimizations depending on it will
+be disabled. The default maximum SCC size is 10000.
+
+@item ira-max-loops-num
+IRA uses a regional register allocation by default. If a function
+contains loops more than number given by the parameter, only at most
+given number of the most frequently executed loops will form regions
+for the regional register allocation. The default value of the
+parameter is 100.
+
+@item ira-max-conflict-table-size
+Although IRA uses a sophisticated algorithm of compression conflict
+table, the table can be still big for huge functions. If the conflict
+table for a function could be more than size in MB given by the
+parameter, the conflict table is not built and faster, simpler, and
+lower quality register allocation algorithm will be used. The
+algorithm do not use pseudo-register conflicts. The default value of
+the parameter is 2000.
+
+@item loop-invariant-max-bbs-in-loop
+Loop invariant motion can be very expensive, both in compile time and
+in amount of needed compile time memory, with very large loops. Loops
+with more basic blocks than this parameter won't have loop invariant
+motion optimization performed on them. The default value of the
+parameter is 1000 for -O1 and 10000 for -O2 and above.
-@item %[@var{name}]
-Like @samp{%(@dots{})} but put @samp{__} around @option{-D} arguments.
+@end table
+@end table
-@item %x@{@var{option}@}
-Accumulate an option for @samp{%X}.
+@node Preprocessor Options
+@section Options Controlling the Preprocessor
+@cindex preprocessor options
+@cindex options, preprocessor
-@item %X
-Output the accumulated linker options specified by @option{-Wl} or a @samp{%x}
-spec string.
+These options control the C preprocessor, which is run on each C source
+file before actual compilation.
-@item %Y
-Output the accumulated assembler options specified by @option{-Wa}.
+If you use the @option{-E} option, nothing is done except preprocessing.
+Some of these options make sense only together with @option{-E} because
+they cause the preprocessor output to be unsuitable for actual
+compilation.
-@item %Z
-Output the accumulated preprocessor options specified by @option{-Wp}.
+@table @gcctabopt
+@item -Wp,@var{option}
+@opindex Wp
+You can use @option{-Wp,@var{option}} to bypass the compiler driver
+and pass @var{option} directly through to the preprocessor. If
+@var{option} contains commas, it is split into multiple options at the
+commas. However, many options are modified, translated or interpreted
+by the compiler driver before being passed to the preprocessor, and
+@option{-Wp} forcibly bypasses this phase. The preprocessor's direct
+interface is undocumented and subject to change, so whenever possible
+you should avoid using @option{-Wp} and let the driver handle the
+options instead.
-@item %v1
-Substitute the major version number of GCC@.
-(For version 2.9.5, this is 2.)
+@item -Xpreprocessor @var{option}
+@opindex Xpreprocessor
+Pass @var{option} as an option to the preprocessor. You can use this to
+supply system-specific preprocessor options which GCC does not know how to
+recognize.
-@item %v2
-Substitute the minor version number of GCC@.
-(For version 2.9.5, this is 9.)
+If you want to pass an option that takes an argument, you must use
+@option{-Xpreprocessor} twice, once for the option and once for the argument.
+@end table
-@item %v3
-Substitute the patch level number of GCC@.
-(For version 2.9.5, this is 5.)
+@include cppopts.texi
-@item %a
-Process the @code{asm} spec. This is used to compute the
-switches to be passed to the assembler.
+@node Assembler Options
+@section Passing Options to the Assembler
-@item %A
-Process the @code{asm_final} spec. This is a spec string for
-passing switches to an assembler post-processor, if such a program is
-needed.
+@c prevent bad page break with this line
+You can pass options to the assembler.
-@item %l
-Process the @code{link} spec. This is the spec for computing the
-command line passed to the linker. Typically it will make use of the
-@samp{%L %G %S %D and %E} sequences.
+@table @gcctabopt
+@item -Wa,@var{option}
+@opindex Wa
+Pass @var{option} as an option to the assembler. If @var{option}
+contains commas, it is split into multiple options at the commas.
-@item %D
-Dump out a @option{-L} option for each directory that GCC believes might
-contain startup files. If the target supports multilibs then the
-current multilib directory will be prepended to each of these paths.
+@item -Xassembler @var{option}
+@opindex Xassembler
+Pass @var{option} as an option to the assembler. You can use this to
+supply system-specific assembler options which GCC does not know how to
+recognize.
-@item %M
-Output the multilib directory with directory separators replaced with
-@samp{_}. If multilib directories are not set, or the multilib directory is
-@file{.} then this option emits nothing.
+If you want to pass an option that takes an argument, you must use
+@option{-Xassembler} twice, once for the option and once for the argument.
-@item %L
-Process the @code{lib} spec. This is a spec string for deciding which
-libraries should be included on the command line to the linker.
+@end table
-@item %G
-Process the @code{libgcc} spec. This is a spec string for deciding
-which GCC support library should be included on the command line to the linker.
+@node Link Options
+@section Options for Linking
+@cindex link options
+@cindex options, linking
-@item %S
-Process the @code{startfile} spec. This is a spec for deciding which
-object files should be the first ones passed to the linker. Typically
-this might be a file named @file{crt0.o}.
+These options come into play when the compiler links object files into
+an executable output file. They are meaningless if the compiler is
+not doing a link step.
-@item %E
-Process the @code{endfile} spec. This is a spec string that specifies
-the last object files that will be passed to the linker.
+@table @gcctabopt
+@cindex file names
+@item @var{object-file-name}
+A file name that does not end in a special recognized suffix is
+considered to name an object file or library. (Object files are
+distinguished from libraries by the linker according to the file
+contents.) If linking is done, these object files are used as input
+to the linker.
-@item %C
-Process the @code{cpp} spec. This is used to construct the arguments
-to be passed to the C preprocessor.
+@item -c
+@itemx -S
+@itemx -E
+@opindex c
+@opindex S
+@opindex E
+If any of these options is used, then the linker is not run, and
+object file names should not be used as arguments. @xref{Overall
+Options}.
-@item %c
-Process the @code{signed_char} spec. This is intended to be used
-to tell cpp whether a char is signed. It typically has the definition:
-@smallexample
-%@{funsigned-char:-D__CHAR_UNSIGNED__@}
-@end smallexample
+@cindex Libraries
+@item -l@var{library}
+@itemx -l @var{library}
+@opindex l
+Search the library named @var{library} when linking. (The second
+alternative with the library as a separate argument is only for
+POSIX compliance and is not recommended.)
-@item %1
-Process the @code{cc1} spec. This is used to construct the options to be
-passed to the actual C compiler (@samp{cc1}).
+It makes a difference where in the command you write this option; the
+linker searches and processes libraries and object files in the order they
+are specified. Thus, @samp{foo.o -lz bar.o} searches library @samp{z}
+after file @file{foo.o} but before @file{bar.o}. If @file{bar.o} refers
+to functions in @samp{z}, those functions may not be loaded.
-@item %2
-Process the @code{cc1plus} spec. This is used to construct the options to be
-passed to the actual C++ compiler (@samp{cc1plus}).
+The linker searches a standard list of directories for the library,
+which is actually a file named @file{lib@var{library}.a}. The linker
+then uses this file as if it had been specified precisely by name.
-@item %*
-Substitute the variable part of a matched option. See below.
-Note that each comma in the substituted string is replaced by
-a single space.
+The directories searched include several standard system directories
+plus any that you specify with @option{-L}.
-@item %@{@code{S}@}
-Substitutes the @code{-S} switch, if that switch was given to GCC@.
-If that switch was not specified, this substitutes nothing. Note that
-the leading dash is omitted when specifying this option, and it is
-automatically inserted if the substitution is performed. Thus the spec
-string @samp{%@{foo@}} would match the command-line option @option{-foo}
-and would output the command line option @option{-foo}.
+Normally the files found this way are library files---archive files
+whose members are object files. The linker handles an archive file by
+scanning through it for members which define symbols that have so far
+been referenced but not defined. But if the file that is found is an
+ordinary object file, it is linked in the usual fashion. The only
+difference between using an @option{-l} option and specifying a file name
+is that @option{-l} surrounds @var{library} with @samp{lib} and @samp{.a}
+and searches several directories.
-@item %W@{@code{S}@}
-Like %@{@code{S}@} but mark last argument supplied within as a file to be
-deleted on failure.
+@item -lobjc
+@opindex lobjc
+You need this special case of the @option{-l} option in order to
+link an Objective-C or Objective-C++ program.
-@item %@{@code{S}*@}
-Substitutes all the switches specified to GCC whose names start
-with @code{-S}, but which also take an argument. This is used for
-switches like @option{-o}, @option{-D}, @option{-I}, etc.
-GCC considers @option{-o foo} as being
-one switch whose names starts with @samp{o}. %@{o*@} would substitute this
-text, including the space. Thus two arguments would be generated.
+@item -nostartfiles
+@opindex nostartfiles
+Do not use the standard system startup files when linking.
+The standard system libraries are used normally, unless @option{-nostdlib}
+or @option{-nodefaultlibs} is used.
-@item %@{^@code{S}*@}
-Like %@{@code{S}*@}, but don't put a blank between a switch and its
-argument. Thus %@{^o*@} would only generate one argument, not two.
+@item -nodefaultlibs
+@opindex nodefaultlibs
+Do not use the standard system libraries when linking.
+Only the libraries you specify will be passed to the linker.
+The standard startup files are used normally, unless @option{-nostartfiles}
+is used. The compiler may generate calls to @code{memcmp},
+@code{memset}, @code{memcpy} and @code{memmove}.
+These entries are usually resolved by entries in
+libc. These entry points should be supplied through some other
+mechanism when this option is specified.
-@item %@{@code{S}*&@code{T}*@}
-Like %@{@code{S}*@}, but preserve order of @code{S} and @code{T} options
-(the order of @code{S} and @code{T} in the spec is not significant).
-There can be any number of ampersand-separated variables; for each the
-wild card is optional. Useful for CPP as @samp{%@{D*&U*&A*@}}.
+@item -nostdlib
+@opindex nostdlib
+Do not use the standard system startup files or libraries when linking.
+No startup files and only the libraries you specify will be passed to
+the linker. The compiler may generate calls to @code{memcmp}, @code{memset},
+@code{memcpy} and @code{memmove}.
+These entries are usually resolved by entries in
+libc. These entry points should be supplied through some other
+mechanism when this option is specified.
-@item %@{<@code{S}@}
-Remove all occurrences of @code{-S} from the command line. Note---this
-command is position dependent. @samp{%} commands in the spec string
-before this option will see @code{-S}, @samp{%} commands in the spec
-string after this option will not.
+@cindex @option{-lgcc}, use with @option{-nostdlib}
+@cindex @option{-nostdlib} and unresolved references
+@cindex unresolved references and @option{-nostdlib}
+@cindex @option{-lgcc}, use with @option{-nodefaultlibs}
+@cindex @option{-nodefaultlibs} and unresolved references
+@cindex unresolved references and @option{-nodefaultlibs}
+One of the standard libraries bypassed by @option{-nostdlib} and
+@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines
+that GCC uses to overcome shortcomings of particular machines, or special
+needs for some languages.
+(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler
+Collection (GCC) Internals},
+for more discussion of @file{libgcc.a}.)
+In most cases, you need @file{libgcc.a} even when you want to avoid
+other standard libraries. In other words, when you specify @option{-nostdlib}
+or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well.
+This ensures that you have no unresolved references to internal GCC
+library subroutines. (For example, @samp{__main}, used to ensure C++
+constructors will be called; @pxref{Collect2,,@code{collect2}, gccint,
+GNU Compiler Collection (GCC) Internals}.)
-@item %@{@code{S}*:@code{X}@}
-Substitutes @code{X} if one or more switches whose names start with
-@code{-S} are specified to GCC@. Note that the tail part of the
-@code{-S} option (i.e.@: the part matched by the @samp{*}) will be substituted
-for each occurrence of @samp{%*} within @code{X}.
+@item -pie
+@opindex pie
+Produce a position independent executable on targets which support it.
+For predictable results, you must also specify the same set of options
+that were used to generate code (@option{-fpie}, @option{-fPIE},
+or model suboptions) when you specify this option.
+
+@item -rdynamic
+@opindex rdynamic
+Pass the flag @option{-export-dynamic} to the ELF linker, on targets
+that support it. This instructs the linker to add all symbols, not
+only used ones, to the dynamic symbol table. This option is needed
+for some uses of @code{dlopen} or to allow obtaining backtraces
+from within a program.
-@item %@{@code{S}:@code{X}@}
-Substitutes @code{X}, but only if the @samp{-S} switch was given to GCC@.
+@item -s
+@opindex s
+Remove all symbol table and relocation information from the executable.
-@item %@{!@code{S}:@code{X}@}
-Substitutes @code{X}, but only if the @samp{-S} switch was @emph{not} given to GCC@.
+@item -static
+@opindex static
+On systems that support dynamic linking, this prevents linking with the shared
+libraries. On other systems, this option has no effect.
-@item %@{|@code{S}:@code{X}@}
-Like %@{@code{S}:@code{X}@}, but if no @code{S} switch, substitute @samp{-}.
+@item -shared
+@opindex shared
+Produce a shared object which can then be linked with other objects to
+form an executable. Not all systems support this option. For predictable
+results, you must also specify the same set of options that were used to
+generate code (@option{-fpic}, @option{-fPIC}, or model suboptions)
+when you specify this option.@footnote{On some systems, @samp{gcc -shared}
+needs to build supplementary stub code for constructors to work. On
+multi-libbed systems, @samp{gcc -shared} must select the correct support
+libraries to link against. Failing to supply the correct flags may lead
+to subtle defects. Supplying them in cases where they are not necessary
+is innocuous.}
-@item %@{|!@code{S}:@code{X}@}
-Like %@{!@code{S}:@code{X}@}, but if there is an @code{S} switch, substitute @samp{-}.
+@item -shared-libgcc
+@itemx -static-libgcc
+@opindex shared-libgcc
+@opindex static-libgcc
+On systems that provide @file{libgcc} as a shared library, these options
+force the use of either the shared or static version respectively.
+If no shared version of @file{libgcc} was built when the compiler was
+configured, these options have no effect.
-@item %@{.@code{S}:@code{X}@}
-Substitutes @code{X}, but only if processing a file with suffix @code{S}.
+There are several situations in which an application should use the
+shared @file{libgcc} instead of the static version. The most common
+of these is when the application wishes to throw and catch exceptions
+across different shared libraries. In that case, each of the libraries
+as well as the application itself should use the shared @file{libgcc}.
-@item %@{!.@code{S}:@code{X}@}
-Substitutes @code{X}, but only if @emph{not} processing a file with suffix @code{S}.
+Therefore, the G++ and GCJ drivers automatically add
+@option{-shared-libgcc} whenever you build a shared library or a main
+executable, because C++ and Java programs typically use exceptions, so
+this is the right thing to do.
-@item %@{@code{S}|@code{P}:@code{X}@}
-Substitutes @code{X} if either @code{-S} or @code{-P} was given to GCC@. This may be
-combined with @samp{!} and @samp{.} sequences as well, although they
-have a stronger binding than the @samp{|}. For example a spec string
-like this:
+If, instead, you use the GCC driver to create shared libraries, you may
+find that they will not always be linked with the shared @file{libgcc}.
+If GCC finds, at its configuration time, that you have a non-GNU linker
+or a GNU linker that does not support option @option{--eh-frame-hdr},
+it will link the shared version of @file{libgcc} into shared libraries
+by default. Otherwise, it will take advantage of the linker and optimize
+away the linking with the shared version of @file{libgcc}, linking with
+the static version of libgcc by default. This allows exceptions to
+propagate through such shared libraries, without incurring relocation
+costs at library load time.
-@smallexample
-%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
-@end smallexample
+However, if a library or main executable is supposed to throw or catch
+exceptions, you must link it using the G++ or GCJ driver, as appropriate
+for the languages used in the program, or using the option
+@option{-shared-libgcc}, such that it is linked with the shared
+@file{libgcc}.
-will output the following command-line options from the following input
-command-line options:
+@item -symbolic
+@opindex symbolic
+Bind references to global symbols when building a shared object. Warn
+about any unresolved references (unless overridden by the link editor
+option @samp{-Xlinker -z -Xlinker defs}). Only a few systems support
+this option.
-@smallexample
-fred.c -foo -baz
-jim.d -bar -boggle
--d fred.c -foo -baz -boggle
--d jim.d -bar -baz -boggle
-@end smallexample
+@item -T @var{script}
+@opindex T
+@cindex linker script
+Use @var{script} as the linker script. This option is supported by most
+systems using the GNU linker. On some targets, such as bare-board
+targets without an operating system, the @option{-T} option may be required
+when linking to avoid references to undefined symbols.
+
+@item -Xlinker @var{option}
+@opindex Xlinker
+Pass @var{option} as an option to the linker. You can use this to
+supply system-specific linker options which GCC does not know how to
+recognize.
+
+If you want to pass an option that takes a separate argument, you must use
+@option{-Xlinker} twice, once for the option and once for the argument.
+For example, to pass @option{-assert definitions}, you must write
+@samp{-Xlinker -assert -Xlinker definitions}. It does not work to write
+@option{-Xlinker "-assert definitions"}, because this passes the entire
+string as a single argument, which is not what the linker expects.
+
+When using the GNU linker, it is usually more convenient to pass
+arguments to linker options using the @option{@var{option}=@var{value}}
+syntax than as separate arguments. For example, you can specify
+@samp{-Xlinker -Map=output.map} rather than
+@samp{-Xlinker -Map -Xlinker output.map}. Other linkers may not support
+this syntax for command-line options.
+@item -Wl,@var{option}
+@opindex Wl
+Pass @var{option} as an option to the linker. If @var{option} contains
+commas, it is split into multiple options at the commas. You can use this
+syntax to pass an argument to the option.
+For example, @samp{-Wl,-Map,output.map} passes @samp{-Map output.map} to the
+linker. When using the GNU linker, you can also get the same effect with
+@samp{-Wl,-Map=output.map}.
+
+@item -u @var{symbol}
+@opindex u
+Pretend the symbol @var{symbol} is undefined, to force linking of
+library modules to define it. You can use @option{-u} multiple times with
+different symbols to force loading of additional library modules.
@end table
-The conditional text @code{X} in a %@{@code{S}:@code{X}@} or
-%@{!@code{S}:@code{X}@} construct may contain other nested @samp{%} constructs
-or spaces, or even newlines. They are processed as usual, as described
-above.
+@node Directory Options
+@section Options for Directory Search
+@cindex directory options
+@cindex options, directory search
+@cindex search path
-The @option{-O}, @option{-f}, @option{-m}, and @option{-W}
-switches are handled specifically in these
-constructs. If another value of @option{-O} or the negated form of a @option{-f}, @option{-m}, or
-@option{-W} switch is found later in the command line, the earlier switch
-value is ignored, except with @{@code{S}*@} where @code{S} is just one
-letter, which passes all matching options.
+These options specify directories to search for header files, for
+libraries and for parts of the compiler:
-The character @samp{|} at the beginning of the predicate text is used to indicate
-that a command should be piped to the following command, but only if @option{-pipe}
-is specified.
+@table @gcctabopt
+@item -I@var{dir}
+@opindex I
+Add the directory @var{dir} to the head of the list of directories to be
+searched for header files. This can be used to override a system header
+file, substituting your own version, since these directories are
+searched before the system header file directories. However, you should
+not use this option to add directories that contain vendor-supplied
+system header files (use @option{-isystem} for that). If you use more than
+one @option{-I} option, the directories are scanned in left-to-right
+order; the standard system directories come after.
-It is built into GCC which switches take arguments and which do not.
-(You might think it would be useful to generalize this to allow each
-compiler's spec to say which switches take arguments. But this cannot
-be done in a consistent fashion. GCC cannot even decide which input
-files have been specified without knowing which switches take arguments,
-and it must know which input files to compile in order to tell which
-compilers to run).
+If a standard system include directory, or a directory specified with
+@option{-isystem}, is also specified with @option{-I}, the @option{-I}
+option will be ignored. The directory will still be searched but as a
+system directory at its normal position in the system include chain.
+This is to ensure that GCC's procedure to fix buggy system headers and
+the ordering for the include_next directive are not inadvertently changed.
+If you really need to change the search order for system directories,
+use the @option{-nostdinc} and/or @option{-isystem} options.
-GCC also knows implicitly that arguments starting in @option{-l} are to be
-treated as compiler output files, and passed to the linker in their
-proper position among the other output files.
+@item -iquote@var{dir}
+@opindex iquote
+Add the directory @var{dir} to the head of the list of directories to
+be searched for header files only for the case of @samp{#include
+"@var{file}"}; they are not searched for @samp{#include <@var{file}>},
+otherwise just like @option{-I}.
-@c man begin OPTIONS
+@item -L@var{dir}
+@opindex L
+Add directory @var{dir} to the list of directories to be searched
+for @option{-l}.
-@node Target Options
-@section Specifying Target Machine and Compiler Version
-@cindex target options
-@cindex cross compiling
-@cindex specifying machine version
-@cindex specifying compiler version and target machine
-@cindex compiler version, specifying
-@cindex target machine, specifying
+@item -B@var{prefix}
+@opindex B
+This option specifies where to find the executables, libraries,
+include files, and data files of the compiler itself.
-By default, GCC compiles code for the same type of machine that you
-are using. However, it can also be installed as a cross-compiler, to
-compile for some other type of machine. In fact, several different
-configurations of GCC, for different target machines, can be
-installed side by side. Then you specify which one to use with the
-@option{-b} option.
+The compiler driver program runs one or more of the subprograms
+@file{cpp}, @file{cc1}, @file{as} and @file{ld}. It tries
+@var{prefix} as a prefix for each program it tries to run, both with and
+without @samp{@var{machine}/@var{version}/} (@pxref{Target Options}).
-In addition, older and newer versions of GCC can be installed side
-by side. One of them (probably the newest) will be the default, but
-you may sometimes wish to use another.
+For each subprogram to be run, the compiler driver first tries the
+@option{-B} prefix, if any. If that name is not found, or if @option{-B}
+was not specified, the driver tries two standard prefixes, which are
+@file{/usr/lib/gcc/} and @file{/usr/local/lib/gcc/}. If neither of
+those results in a file name that is found, the unmodified program
+name is searched for using the directories specified in your
+@env{PATH} environment variable.
-@table @gcctabopt
-@item -b @var{machine}
-@opindex b
-The argument @var{machine} specifies the target machine for compilation.
-This is useful when you have installed GCC as a cross-compiler.
+The compiler will check to see if the path provided by the @option{-B}
+refers to a directory, and if necessary it will add a directory
+separator character at the end of the path.
-The value to use for @var{machine} is the same as was specified as the
-machine type when configuring GCC as a cross-compiler. For
-example, if a cross-compiler was configured with @samp{configure
-i386v}, meaning to compile for an 80386 running System V, then you
-would specify @option{-b i386v} to run that cross compiler.
+@option{-B} prefixes that effectively specify directory names also apply
+to libraries in the linker, because the compiler translates these
+options into @option{-L} options for the linker. They also apply to
+includes files in the preprocessor, because the compiler translates these
+options into @option{-isystem} options for the preprocessor. In this case,
+the compiler appends @samp{include} to the prefix.
-When you do not specify @option{-b}, it normally means to compile for
-the same type of machine that you are using.
+The run-time support file @file{libgcc.a} can also be searched for using
+the @option{-B} prefix, if needed. If it is not found there, the two
+standard prefixes above are tried, and that is all. The file is left
+out of the link if it is not found by those means.
-@item -V @var{version}
-@opindex V
-The argument @var{version} specifies which version of GCC to run.
-This is useful when multiple versions are installed. For example,
-@var{version} might be @samp{2.0}, meaning to run GCC version 2.0.
+Another way to specify a prefix much like the @option{-B} prefix is to use
+the environment variable @env{GCC_EXEC_PREFIX}. @xref{Environment
+Variables}.
-The default version, when you do not specify @option{-V}, is the last
-version of GCC that you installed.
-@end table
+As a special kludge, if the path provided by @option{-B} is
+@file{[dir/]stage@var{N}/}, where @var{N} is a number in the range 0 to
+9, then it will be replaced by @file{[dir/]include}. This is to help
+with boot-strapping the compiler.
-The @option{-b} and @option{-V} options actually work by controlling part of
-the file name used for the executable files and libraries used for
-compilation. A given version of GCC, for a given target machine, is
-normally kept in the directory @file{/usr/local/lib/gcc-lib/@var{machine}/@var{version}}.
-
-Thus, sites can customize the effect of @option{-b} or @option{-V} either by
-changing the names of these directories or adding alternate names (or
-symbolic links). If in directory @file{/usr/local/lib/gcc-lib/} the
-file @file{80386} is a link to the file @file{i386v}, then @option{-b
-80386} becomes an alias for @option{-b i386v}.
-
-In one respect, the @option{-b} or @option{-V} do not completely change
-to a different compiler: the top-level driver program @command{gcc}
-that you originally invoked continues to run and invoke the other
-executables (preprocessor, compiler per se, assembler and linker)
-that do the real work. However, since no real work is done in the
-driver program, it usually does not matter that the driver program
-in use is not the one for the specified target. It is common for the
-interface to the other executables to change incompatibly between
-compiler versions, so unless the version specified is very close to that
-of the driver (for example, @option{-V 3.0} with a driver program from GCC
-version 3.0.1), use of @option{-V} may not work; for example, using
-@option{-V 2.95.2} will not work with a driver program from GCC 3.0.
-
-The only way that the driver program depends on the target machine is
-in the parsing and handling of special machine-specific options.
-However, this is controlled by a file which is found, along with the
-other executables, in the directory for the specified version and
-target machine. As a result, a single installed driver program adapts
-to any specified target machine, and sufficiently similar compiler
-versions.
-
-The driver program executable does control one significant thing,
-however: the default version and target machine. Therefore, you can
-install different instances of the driver program, compiled for
-different targets or versions, under different names.
-
-For example, if the driver for version 2.0 is installed as @command{ogcc}
-and that for version 2.1 is installed as @command{gcc}, then the command
-@command{gcc} will use version 2.1 by default, while @command{ogcc} will use
-2.0 by default. However, you can choose either version with either
-command with the @option{-V} option.
+@item -specs=@var{file}
+@opindex specs
+Process @var{file} after the compiler reads in the standard @file{specs}
+file, in order to override the defaults that the @file{gcc} driver
+program uses when determining what switches to pass to @file{cc1},
+@file{cc1plus}, @file{as}, @file{ld}, etc. More than one
+@option{-specs=@var{file}} can be specified on the command line, and they
+are processed in order, from left to right.
-@node Submodel Options
-@section Hardware Models and Configurations
-@cindex submodel options
-@cindex specifying hardware config
-@cindex hardware models and configurations, specifying
-@cindex machine dependent options
+@item --sysroot=@var{dir}
+@opindex sysroot
+Use @var{dir} as the logical root directory for headers and libraries.
+For example, if the compiler would normally search for headers in
+@file{/usr/include} and libraries in @file{/usr/lib}, it will instead
+search @file{@var{dir}/usr/include} and @file{@var{dir}/usr/lib}.
-Earlier we discussed the standard option @option{-b} which chooses among
-different installed compilers for completely different target
-machines, such as VAX vs.@: 68000 vs.@: 80386.
+If you use both this option and the @option{-isysroot} option, then
+the @option{--sysroot} option will apply to libraries, but the
+@option{-isysroot} option will apply to header files.
-In addition, each of these target machine types can have its own
-special options, starting with @samp{-m}, to choose among various
-hardware models or configurations---for example, 68010 vs 68020,
-floating coprocessor or none. A single installed version of the
-compiler can compile for any model or configuration, according to the
-options specified.
+The GNU linker (beginning with version 2.16) has the necessary support
+for this option. If your linker does not support this option, the
+header file aspect of @option{--sysroot} will still work, but the
+library aspect will not.
-Some configurations of the compiler also support additional special
-options, usually for compatibility with other compilers on the same
-platform.
+@item -I-
+@opindex I-
+This option has been deprecated. Please use @option{-iquote} instead for
+@option{-I} directories before the @option{-I-} and remove the @option{-I-}.
+Any directories you specify with @option{-I} options before the @option{-I-}
+option are searched only for the case of @samp{#include "@var{file}"};
+they are not searched for @samp{#include <@var{file}>}.
-These options are defined by the macro @code{TARGET_SWITCHES} in the
-machine description. The default for the options is also defined by
-that macro, which enables you to change the defaults.
+If additional directories are specified with @option{-I} options after
+the @option{-I-}, these directories are searched for all @samp{#include}
+directives. (Ordinarily @emph{all} @option{-I} directories are used
+this way.)
-@menu
-* M680x0 Options::
-* M68hc1x Options::
-* VAX Options::
-* SPARC Options::
-* Convex Options::
-* AMD29K Options::
-* ARM Options::
-* MN10200 Options::
-* MN10300 Options::
-* M32R/D Options::
-* M88K Options::
-* RS/6000 and PowerPC Options::
-* RT Options::
-* MIPS Options::
-* i386 and x86-64 Options::
-* HPPA Options::
-* Intel 960 Options::
-* DEC Alpha Options::
-* DEC Alpha/VMS Options::
-* Clipper Options::
-* H8/300 Options::
-* SH Options::
-* System V Options::
-* TMS320C3x/C4x Options::
-* V850 Options::
-* ARC Options::
-* NS32K Options::
-* AVR Options::
-* MCore Options::
-* IA-64 Options::
-* D30V Options::
-* S/390 and zSeries Options::
-* CRIS Options::
-* MMIX Options::
-* PDP-11 Options::
-* Xstormy16 Options::
-* Xtensa Options::
-@end menu
-
-@node M680x0 Options
-@subsection M680x0 Options
-@cindex M680x0 options
+In addition, the @option{-I-} option inhibits the use of the current
+directory (where the current input file came from) as the first search
+directory for @samp{#include "@var{file}"}. There is no way to
+override this effect of @option{-I-}. With @option{-I.} you can specify
+searching the directory which was current when the compiler was
+invoked. That is not exactly the same as what the preprocessor does
+by default, but it is often satisfactory.
-These are the @samp{-m} options defined for the 68000 series. The default
-values for these options depends on which style of 68000 was selected when
-the compiler was configured; the defaults for the most common choices are
-given below.
+@option{-I-} does not inhibit the use of the standard system directories
+for header files. Thus, @option{-I-} and @option{-nostdinc} are
+independent.
+@end table
-@table @gcctabopt
-@item -m68000
-@itemx -mc68000
-@opindex m68000
-@opindex mc68000
-Generate output for a 68000. This is the default
-when the compiler is configured for 68000-based systems.
+@c man end
-Use this option for microcontrollers with a 68000 or EC000 core,
-including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.
+@node Spec Files
+@section Specifying subprocesses and the switches to pass to them
+@cindex Spec Files
-@item -m68020
-@itemx -mc68020
-@opindex m68020
-@opindex mc68020
-Generate output for a 68020. This is the default
-when the compiler is configured for 68020-based systems.
+@command{gcc} is a driver program. It performs its job by invoking a
+sequence of other programs to do the work of compiling, assembling and
+linking. GCC interprets its command-line parameters and uses these to
+deduce which programs it should invoke, and which command-line options
+it ought to place on their command lines. This behavior is controlled
+by @dfn{spec strings}. In most cases there is one spec string for each
+program that GCC can invoke, but a few programs have multiple spec
+strings to control their behavior. The spec strings built into GCC can
+be overridden by using the @option{-specs=} command-line switch to specify
+a spec file.
-@item -m68881
-@opindex m68881
-Generate output containing 68881 instructions for floating point.
-This is the default for most 68020 systems unless @option{--nfp} was
-specified when the compiler was configured.
+@dfn{Spec files} are plaintext files that are used to construct spec
+strings. They consist of a sequence of directives separated by blank
+lines. The type of directive is determined by the first non-whitespace
+character on the line and it can be one of the following:
-@item -m68030
-@opindex m68030
-Generate output for a 68030. This is the default when the compiler is
-configured for 68030-based systems.
+@table @code
+@item %@var{command}
+Issues a @var{command} to the spec file processor. The commands that can
+appear here are:
-@item -m68040
-@opindex m68040
-Generate output for a 68040. This is the default when the compiler is
-configured for 68040-based systems.
+@table @code
+@item %include <@var{file}>
+@cindex %include
+Search for @var{file} and insert its text at the current point in the
+specs file.
-This option inhibits the use of 68881/68882 instructions that have to be
-emulated by software on the 68040. Use this option if your 68040 does not
-have code to emulate those instructions.
+@item %include_noerr <@var{file}>
+@cindex %include_noerr
+Just like @samp{%include}, but do not generate an error message if the include
+file cannot be found.
-@item -m68060
-@opindex m68060
-Generate output for a 68060. This is the default when the compiler is
-configured for 68060-based systems.
+@item %rename @var{old_name} @var{new_name}
+@cindex %rename
+Rename the spec string @var{old_name} to @var{new_name}.
-This option inhibits the use of 68020 and 68881/68882 instructions that
-have to be emulated by software on the 68060. Use this option if your 68060
-does not have code to emulate those instructions.
+@end table
-@item -mcpu32
-@opindex mcpu32
-Generate output for a CPU32. This is the default
-when the compiler is configured for CPU32-based systems.
+@item *[@var{spec_name}]:
+This tells the compiler to create, override or delete the named spec
+string. All lines after this directive up to the next directive or
+blank line are considered to be the text for the spec string. If this
+results in an empty string then the spec will be deleted. (Or, if the
+spec did not exist, then nothing will happened.) Otherwise, if the spec
+does not currently exist a new spec will be created. If the spec does
+exist then its contents will be overridden by the text of this
+directive, unless the first character of that text is the @samp{+}
+character, in which case the text will be appended to the spec.
-Use this option for microcontrollers with a
-CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334,
-68336, 68340, 68341, 68349 and 68360.
+@item [@var{suffix}]:
+Creates a new @samp{[@var{suffix}] spec} pair. All lines after this directive
+and up to the next directive or blank line are considered to make up the
+spec string for the indicated suffix. When the compiler encounters an
+input file with the named suffix, it will processes the spec string in
+order to work out how to compile that file. For example:
-@item -m5200
-@opindex m5200
-Generate output for a 520X ``coldfire'' family cpu. This is the default
-when the compiler is configured for 520X-based systems.
+@smallexample
+.ZZ:
+z-compile -input %i
+@end smallexample
-Use this option for microcontroller with a 5200 core, including
-the MCF5202, MCF5203, MCF5204 and MCF5202.
+This says that any input file whose name ends in @samp{.ZZ} should be
+passed to the program @samp{z-compile}, which should be invoked with the
+command-line switch @option{-input} and with the result of performing the
+@samp{%i} substitution. (See below.)
+As an alternative to providing a spec string, the text that follows a
+suffix directive can be one of the following:
-@item -m68020-40
-@opindex m68020-40
-Generate output for a 68040, without using any of the new instructions.
-This results in code which can run relatively efficiently on either a
-68020/68881 or a 68030 or a 68040. The generated code does use the
-68881 instructions that are emulated on the 68040.
+@table @code
+@item @@@var{language}
+This says that the suffix is an alias for a known @var{language}. This is
+similar to using the @option{-x} command-line switch to GCC to specify a
+language explicitly. For example:
-@item -m68020-60
-@opindex m68020-60
-Generate output for a 68060, without using any of the new instructions.
-This results in code which can run relatively efficiently on either a
-68020/68881 or a 68030 or a 68040. The generated code does use the
-68881 instructions that are emulated on the 68060.
+@smallexample
+.ZZ:
+@@c++
+@end smallexample
-@item -mfpa
-@opindex mfpa
-Generate output containing Sun FPA instructions for floating point.
+Says that .ZZ files are, in fact, C++ source files.
-@item -msoft-float
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not available for all m68k
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this can't be done directly in cross-compilation. You must
-make your own arrangements to provide suitable library functions for
-cross-compilation. The embedded targets @samp{m68k-*-aout} and
-@samp{m68k-*-coff} do provide software floating point support.
+@item #@var{name}
+This causes an error messages saying:
-@item -mshort
-@opindex mshort
-Consider type @code{int} to be 16 bits wide, like @code{short int}.
+@smallexample
+@var{name} compiler not installed on this system.
+@end smallexample
+@end table
-@item -mnobitfield
-@opindex mnobitfield
-Do not use the bit-field instructions. The @option{-m68000}, @option{-mcpu32}
-and @option{-m5200} options imply @w{@option{-mnobitfield}}.
+GCC already has an extensive list of suffixes built into it.
+This directive will add an entry to the end of the list of suffixes, but
+since the list is searched from the end backwards, it is effectively
+possible to override earlier entries using this technique.
-@item -mbitfield
-@opindex mbitfield
-Do use the bit-field instructions. The @option{-m68020} option implies
-@option{-mbitfield}. This is the default if you use a configuration
-designed for a 68020.
+@end table
-@item -mrtd
-@opindex mrtd
-Use a different function-calling convention, in which functions
-that take a fixed number of arguments return with the @code{rtd}
-instruction, which pops their arguments while returning. This
-saves one instruction in the caller since there is no need to pop
-the arguments there.
+GCC has the following spec strings built into it. Spec files can
+override these strings or create their own. Note that individual
+targets can also add their own spec strings to this list.
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
+@smallexample
+asm Options to pass to the assembler
+asm_final Options to pass to the assembler post-processor
+cpp Options to pass to the C preprocessor
+cc1 Options to pass to the C compiler
+cc1plus Options to pass to the C++ compiler
+endfile Object files to include at the end of the link
+link Options to pass to the linker
+lib Libraries to include on the command line to the linker
+libgcc Decides which GCC support library to pass to the linker
+linker Sets the name of the linker
+predefines Defines to be passed to the C preprocessor
+signed_char Defines to pass to CPP to say whether @code{char} is signed
+ by default
+startfile Object files to include at the start of the link
+@end smallexample
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including @code{printf});
-otherwise incorrect code will be generated for calls to those
-functions.
+Here is a small example of a spec file:
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
+@smallexample
+%rename lib old_lib
-The @code{rtd} instruction is supported by the 68010, 68020, 68030,
-68040, 68060 and CPU32 processors, but not by the 68000 or 5200.
+*lib:
+--start-group -lgcc -lc -leval1 --end-group %(old_lib)
+@end smallexample
-@item -malign-int
-@itemx -mno-align-int
-@opindex malign-int
-@opindex mno-align-int
-Control whether GCC aligns @code{int}, @code{long}, @code{long long},
-@code{float}, @code{double}, and @code{long double} variables on a 32-bit
-boundary (@option{-malign-int}) or a 16-bit boundary (@option{-mno-align-int}).
-Aligning variables on 32-bit boundaries produces code that runs somewhat
-faster on processors with 32-bit busses at the expense of more memory.
+This example renames the spec called @samp{lib} to @samp{old_lib} and
+then overrides the previous definition of @samp{lib} with a new one.
+The new definition adds in some extra command-line options before
+including the text of the old definition.
-@strong{Warning:} if you use the @option{-malign-int} switch, GCC will
-align structures containing the above types differently than
-most published application binary interface specifications for the m68k.
+@dfn{Spec strings} are a list of command-line options to be passed to their
+corresponding program. In addition, the spec strings can contain
+@samp{%}-prefixed sequences to substitute variable text or to
+conditionally insert text into the command line. Using these constructs
+it is possible to generate quite complex command lines.
-@item -mpcrel
-@opindex mpcrel
-Use the pc-relative addressing mode of the 68000 directly, instead of
-using a global offset table. At present, this option implies @option{-fpic},
-allowing at most a 16-bit offset for pc-relative addressing. @option{-fPIC} is
-not presently supported with @option{-mpcrel}, though this could be supported for
-68020 and higher processors.
+Here is a table of all defined @samp{%}-sequences for spec
+strings. Note that spaces are not generated automatically around the
+results of expanding these sequences. Therefore you can concatenate them
+together or combine them with constant text in a single argument.
-@item -mno-strict-align
-@itemx -mstrict-align
-@opindex mno-strict-align
-@opindex mstrict-align
-Do not (do) assume that unaligned memory references will be handled by
-the system.
+@table @code
+@item %%
+Substitute one @samp{%} into the program name or argument.
-@end table
+@item %i
+Substitute the name of the input file being processed.
-@node M68hc1x Options
-@subsection M68hc1x Options
-@cindex M68hc1x options
+@item %b
+Substitute the basename of the input file being processed.
+This is the substring up to (and not including) the last period
+and not including the directory.
-These are the @samp{-m} options defined for the 68hc11 and 68hc12
-microcontrollers. The default values for these options depends on
-which style of microcontroller was selected when the compiler was configured;
-the defaults for the most common choices are given below.
+@item %B
+This is the same as @samp{%b}, but include the file suffix (text after
+the last period).
-@table @gcctabopt
-@item -m6811
-@itemx -m68hc11
-@opindex m6811
-@opindex m68hc11
-Generate output for a 68HC11. This is the default
-when the compiler is configured for 68HC11-based systems.
+@item %d
+Marks the argument containing or following the @samp{%d} as a
+temporary file name, so that that file will be deleted if GCC exits
+successfully. Unlike @samp{%g}, this contributes no text to the
+argument.
-@item -m6812
-@itemx -m68hc12
-@opindex m6812
-@opindex m68hc12
-Generate output for a 68HC12. This is the default
-when the compiler is configured for 68HC12-based systems.
+@item %g@var{suffix}
+Substitute a file name that has suffix @var{suffix} and is chosen
+once per compilation, and mark the argument in the same way as
+@samp{%d}. To reduce exposure to denial-of-service attacks, the file
+name is now chosen in a way that is hard to predict even when previously
+chosen file names are known. For example, @samp{%g.s @dots{} %g.o @dots{} %g.s}
+might turn into @samp{ccUVUUAU.s ccXYAXZ12.o ccUVUUAU.s}. @var{suffix} matches
+the regexp @samp{[.A-Za-z]*} or the special string @samp{%O}, which is
+treated exactly as if @samp{%O} had been preprocessed. Previously, @samp{%g}
+was simply substituted with a file name chosen once per compilation,
+without regard to any appended suffix (which was therefore treated
+just like ordinary text), making such attacks more likely to succeed.
-@item -mauto-incdec
-@opindex mauto-incdec
-Enable the use of 68HC12 pre and post auto-increment and auto-decrement
-addressing modes.
+@item %u@var{suffix}
+Like @samp{%g}, but generates a new temporary file name even if
+@samp{%u@var{suffix}} was already seen.
-@item -mshort
-@opindex mshort
-Consider type @code{int} to be 16 bits wide, like @code{short int}.
+@item %U@var{suffix}
+Substitutes the last file name generated with @samp{%u@var{suffix}}, generating a
+new one if there is no such last file name. In the absence of any
+@samp{%u@var{suffix}}, this is just like @samp{%g@var{suffix}}, except they don't share
+the same suffix @emph{space}, so @samp{%g.s @dots{} %U.s @dots{} %g.s @dots{} %U.s}
+would involve the generation of two distinct file names, one
+for each @samp{%g.s} and another for each @samp{%U.s}. Previously, @samp{%U} was
+simply substituted with a file name chosen for the previous @samp{%u},
+without regard to any appended suffix.
-@item -msoft-reg-count=@var{count}
-@opindex msoft-reg-count
-Specify the number of pseudo-soft registers which are used for the
-code generation. The maximum number is 32. Using more pseudo-soft
-register may or may not result in better code depending on the program.
-The default is 4 for 68HC11 and 2 for 68HC12.
+@item %j@var{suffix}
+Substitutes the name of the @code{HOST_BIT_BUCKET}, if any, and if it is
+writable, and if save-temps is off; otherwise, substitute the name
+of a temporary file, just like @samp{%u}. This temporary file is not
+meant for communication between processes, but rather as a junk
+disposal mechanism.
-@end table
+@item %|@var{suffix}
+@itemx %m@var{suffix}
+Like @samp{%g}, except if @option{-pipe} is in effect. In that case
+@samp{%|} substitutes a single dash and @samp{%m} substitutes nothing at
+all. These are the two most common ways to instruct a program that it
+should read from standard input or write to standard output. If you
+need something more elaborate you can use an @samp{%@{pipe:@code{X}@}}
+construct: see for example @file{f/lang-specs.h}.
-@node VAX Options
-@subsection VAX Options
-@cindex VAX options
+@item %.@var{SUFFIX}
+Substitutes @var{.SUFFIX} for the suffixes of a matched switch's args
+when it is subsequently output with @samp{%*}. @var{SUFFIX} is
+terminated by the next space or %.
-These @samp{-m} options are defined for the VAX:
+@item %w
+Marks the argument containing or following the @samp{%w} as the
+designated output file of this compilation. This puts the argument
+into the sequence of arguments that @samp{%o} will substitute later.
-@table @gcctabopt
-@item -munix
-@opindex munix
-Do not output certain jump instructions (@code{aobleq} and so on)
-that the Unix assembler for the VAX cannot handle across long
-ranges.
+@item %o
+Substitutes the names of all the output files, with spaces
+automatically placed around them. You should write spaces
+around the @samp{%o} as well or the results are undefined.
+@samp{%o} is for use in the specs for running the linker.
+Input files whose names have no recognized suffix are not compiled
+at all, but they are included among the output files, so they will
+be linked.
-@item -mgnu
-@opindex mgnu
-Do output those jump instructions, on the assumption that you
-will assemble with the GNU assembler.
+@item %O
+Substitutes the suffix for object files. Note that this is
+handled specially when it immediately follows @samp{%g, %u, or %U},
+because of the need for those to form complete file names. The
+handling is such that @samp{%O} is treated exactly as if it had already
+been substituted, except that @samp{%g, %u, and %U} do not currently
+support additional @var{suffix} characters following @samp{%O} as they would
+following, for example, @samp{.o}.
-@item -mg
-@opindex mg
-Output code for g-format floating point numbers instead of d-format.
-@end table
+@item %p
+Substitutes the standard macro predefinitions for the
+current target machine. Use this when running @code{cpp}.
-@node SPARC Options
-@subsection SPARC Options
-@cindex SPARC options
+@item %P
+Like @samp{%p}, but puts @samp{__} before and after the name of each
+predefined macro, except for macros that start with @samp{__} or with
+@samp{_@var{L}}, where @var{L} is an uppercase letter. This is for ISO
+C@.
-These @samp{-m} switches are supported on the SPARC:
+@item %I
+Substitute any of @option{-iprefix} (made from @env{GCC_EXEC_PREFIX}),
+@option{-isysroot} (made from @env{TARGET_SYSTEM_ROOT}),
+@option{-isystem} (made from @env{COMPILER_PATH} and @option{-B} options)
+and @option{-imultilib} as necessary.
-@table @gcctabopt
-@item -mno-app-regs
-@itemx -mapp-regs
-@opindex mno-app-regs
-@opindex mapp-regs
-Specify @option{-mapp-regs} to generate output using the global registers
-2 through 4, which the SPARC SVR4 ABI reserves for applications. This
-is the default.
+@item %s
+Current argument is the name of a library or startup file of some sort.
+Search for that file in a standard list of directories and substitute
+the full name found.
-To be fully SVR4 ABI compliant at the cost of some performance loss,
-specify @option{-mno-app-regs}. You should compile libraries and system
-software with this option.
+@item %e@var{str}
+Print @var{str} as an error message. @var{str} is terminated by a newline.
+Use this when inconsistent options are detected.
-@item -mfpu
-@itemx -mhard-float
-@opindex mfpu
-@opindex mhard-float
-Generate output containing floating point instructions. This is the
-default.
+@item %(@var{name})
+Substitute the contents of spec string @var{name} at this point.
-@item -mno-fpu
-@itemx -msoft-float
-@opindex mno-fpu
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not available for all SPARC
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation. The embedded targets @samp{sparc-*-aout} and
-@samp{sparclite-*-*} do provide software floating point support.
+@item %[@var{name}]
+Like @samp{%(@dots{})} but put @samp{__} around @option{-D} arguments.
-@option{-msoft-float} changes the calling convention in the output file;
-therefore, it is only useful if you compile @emph{all} of a program with
-this option. In particular, you need to compile @file{libgcc.a}, the
-library that comes with GCC, with @option{-msoft-float} in order for
-this to work.
+@item %x@{@var{option}@}
+Accumulate an option for @samp{%X}.
-@item -mhard-quad-float
-@opindex mhard-quad-float
-Generate output containing quad-word (long double) floating point
-instructions.
+@item %X
+Output the accumulated linker options specified by @option{-Wl} or a @samp{%x}
+spec string.
-@item -msoft-quad-float
-@opindex msoft-quad-float
-Generate output containing library calls for quad-word (long double)
-floating point instructions. The functions called are those specified
-in the SPARC ABI@. This is the default.
+@item %Y
+Output the accumulated assembler options specified by @option{-Wa}.
-As of this writing, there are no sparc implementations that have hardware
-support for the quad-word floating point instructions. They all invoke
-a trap handler for one of these instructions, and then the trap handler
-emulates the effect of the instruction. Because of the trap handler overhead,
-this is much slower than calling the ABI library routines. Thus the
-@option{-msoft-quad-float} option is the default.
+@item %Z
+Output the accumulated preprocessor options specified by @option{-Wp}.
-@item -mno-flat
-@itemx -mflat
-@opindex mno-flat
-@opindex mflat
-With @option{-mflat}, the compiler does not generate save/restore instructions
-and will use a ``flat'' or single register window calling convention.
-This model uses %i7 as the frame pointer and is compatible with the normal
-register window model. Code from either may be intermixed.
-The local registers and the input registers (0--5) are still treated as
-``call saved'' registers and will be saved on the stack as necessary.
+@item %a
+Process the @code{asm} spec. This is used to compute the
+switches to be passed to the assembler.
-With @option{-mno-flat} (the default), the compiler emits save/restore
-instructions (except for leaf functions) and is the normal mode of operation.
+@item %A
+Process the @code{asm_final} spec. This is a spec string for
+passing switches to an assembler post-processor, if such a program is
+needed.
-@item -mno-unaligned-doubles
-@itemx -munaligned-doubles
-@opindex mno-unaligned-doubles
-@opindex munaligned-doubles
-Assume that doubles have 8 byte alignment. This is the default.
+@item %l
+Process the @code{link} spec. This is the spec for computing the
+command line passed to the linker. Typically it will make use of the
+@samp{%L %G %S %D and %E} sequences.
-With @option{-munaligned-doubles}, GCC assumes that doubles have 8 byte
-alignment only if they are contained in another type, or if they have an
-absolute address. Otherwise, it assumes they have 4 byte alignment.
-Specifying this option avoids some rare compatibility problems with code
-generated by other compilers. It is not the default because it results
-in a performance loss, especially for floating point code.
+@item %D
+Dump out a @option{-L} option for each directory that GCC believes might
+contain startup files. If the target supports multilibs then the
+current multilib directory will be prepended to each of these paths.
-@item -mno-faster-structs
-@itemx -mfaster-structs
-@opindex mno-faster-structs
-@opindex mfaster-structs
-With @option{-mfaster-structs}, the compiler assumes that structures
-should have 8 byte alignment. This enables the use of pairs of
-@code{ldd} and @code{std} instructions for copies in structure
-assignment, in place of twice as many @code{ld} and @code{st} pairs.
-However, the use of this changed alignment directly violates the Sparc
-ABI@. Thus, it's intended only for use on targets where the developer
-acknowledges that their resulting code will not be directly in line with
-the rules of the ABI@.
+@item %L
+Process the @code{lib} spec. This is a spec string for deciding which
+libraries should be included on the command line to the linker.
-@item -mv8
-@itemx -msparclite
-@opindex mv8
-@opindex msparclite
-These two options select variations on the SPARC architecture.
+@item %G
+Process the @code{libgcc} spec. This is a spec string for deciding
+which GCC support library should be included on the command line to the linker.
-By default (unless specifically configured for the Fujitsu SPARClite),
-GCC generates code for the v7 variant of the SPARC architecture.
+@item %S
+Process the @code{startfile} spec. This is a spec for deciding which
+object files should be the first ones passed to the linker. Typically
+this might be a file named @file{crt0.o}.
-@option{-mv8} will give you SPARC v8 code. The only difference from v7
-code is that the compiler emits the integer multiply and integer
-divide instructions which exist in SPARC v8 but not in SPARC v7.
+@item %E
+Process the @code{endfile} spec. This is a spec string that specifies
+the last object files that will be passed to the linker.
-@option{-msparclite} will give you SPARClite code. This adds the integer
-multiply, integer divide step and scan (@code{ffs}) instructions which
-exist in SPARClite but not in SPARC v7.
+@item %C
+Process the @code{cpp} spec. This is used to construct the arguments
+to be passed to the C preprocessor.
-These options are deprecated and will be deleted in a future GCC release.
-They have been replaced with @option{-mcpu=xxx}.
+@item %1
+Process the @code{cc1} spec. This is used to construct the options to be
+passed to the actual C compiler (@samp{cc1}).
-@item -mcypress
-@itemx -msupersparc
-@opindex mcypress
-@opindex msupersparc
-These two options select the processor for which the code is optimized.
+@item %2
+Process the @code{cc1plus} spec. This is used to construct the options to be
+passed to the actual C++ compiler (@samp{cc1plus}).
-With @option{-mcypress} (the default), the compiler optimizes code for the
-Cypress CY7C602 chip, as used in the SparcStation/SparcServer 3xx series.
-This is also appropriate for the older SparcStation 1, 2, IPX etc.
+@item %*
+Substitute the variable part of a matched option. See below.
+Note that each comma in the substituted string is replaced by
+a single space.
-With @option{-msupersparc} the compiler optimizes code for the SuperSparc cpu, as
-used in the SparcStation 10, 1000 and 2000 series. This flag also enables use
-of the full SPARC v8 instruction set.
+@item %<@code{S}
+Remove all occurrences of @code{-S} from the command line. Note---this
+command is position dependent. @samp{%} commands in the spec string
+before this one will see @code{-S}, @samp{%} commands in the spec string
+after this one will not.
-These options are deprecated and will be deleted in a future GCC release.
-They have been replaced with @option{-mcpu=xxx}.
+@item %:@var{function}(@var{args})
+Call the named function @var{function}, passing it @var{args}.
+@var{args} is first processed as a nested spec string, then split
+into an argument vector in the usual fashion. The function returns
+a string which is processed as if it had appeared literally as part
+of the current spec.
-@item -mcpu=@var{cpu_type}
-@opindex mcpu
-Set the instruction set, register set, and instruction scheduling parameters
-for machine type @var{cpu_type}. Supported values for @var{cpu_type} are
-@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite},
-@samp{hypersparc}, @samp{sparclite86x}, @samp{f930}, @samp{f934},
-@samp{sparclet}, @samp{tsc701}, @samp{v9}, and @samp{ultrasparc}.
+The following built-in spec functions are provided:
-Default instruction scheduling parameters are used for values that select
-an architecture and not an implementation. These are @samp{v7}, @samp{v8},
-@samp{sparclite}, @samp{sparclet}, @samp{v9}.
+@table @code
+@item @code{getenv}
+The @code{getenv} spec function takes two arguments: an environment
+variable name and a string. If the environment variable is not
+defined, a fatal error is issued. Otherwise, the return value is the
+value of the environment variable concatenated with the string. For
+example, if @env{TOPDIR} is defined as @file{/path/to/top}, then:
-Here is a list of each supported architecture and their supported
-implementations.
+@smallexample
+%:getenv(TOPDIR /include)
+@end smallexample
+
+expands to @file{/path/to/top/include}.
+
+@item @code{if-exists}
+The @code{if-exists} spec function takes one argument, an absolute
+pathname to a file. If the file exists, @code{if-exists} returns the
+pathname. Here is a small example of its usage:
@smallexample
- v7: cypress
- v8: supersparc, hypersparc
- sparclite: f930, f934, sparclite86x
- sparclet: tsc701
- v9: ultrasparc
+*startfile:
+crt0%O%s %:if-exists(crti%O%s) crtbegin%O%s
@end smallexample
-@item -mtune=@var{cpu_type}
-@opindex mtune
-Set the instruction scheduling parameters for machine type
-@var{cpu_type}, but do not set the instruction set or register set that the
-option @option{-mcpu=@var{cpu_type}} would.
+@item @code{if-exists-else}
+The @code{if-exists-else} spec function is similar to the @code{if-exists}
+spec function, except that it takes two arguments. The first argument is
+an absolute pathname to a file. If the file exists, @code{if-exists-else}
+returns the pathname. If it does not exist, it returns the second argument.
+This way, @code{if-exists-else} can be used to select one file or another,
+based on the existence of the first. Here is a small example of its usage:
-The same values for @option{-mcpu=@var{cpu_type}} can be used for
-@option{-mtune=@var{cpu_type}}, but the only useful values are those
-that select a particular cpu implementation. Those are @samp{cypress},
-@samp{supersparc}, @samp{hypersparc}, @samp{f930}, @samp{f934},
-@samp{sparclite86x}, @samp{tsc701}, and @samp{ultrasparc}.
+@smallexample
+*startfile:
+crt0%O%s %:if-exists(crti%O%s) \
+%:if-exists-else(crtbeginT%O%s crtbegin%O%s)
+@end smallexample
-@end table
+@item @code{replace-outfile}
+The @code{replace-outfile} spec function takes two arguments. It looks for the
+first argument in the outfiles array and replaces it with the second argument. Here
+is a small example of its usage:
-These @samp{-m} switches are supported in addition to the above
-on the SPARCLET processor.
+@smallexample
+%@{fgnu-runtime:%:replace-outfile(-lobjc -lobjc-gnu)@}
+@end smallexample
-@table @gcctabopt
-@item -mlittle-endian
-@opindex mlittle-endian
-Generate code for a processor running in little-endian mode.
-
-@item -mlive-g0
-@opindex mlive-g0
-Treat register @code{%g0} as a normal register.
-GCC will continue to clobber it as necessary but will not assume
-it always reads as 0.
-
-@item -mbroken-saverestore
-@opindex mbroken-saverestore
-Generate code that does not use non-trivial forms of the @code{save} and
-@code{restore} instructions. Early versions of the SPARCLET processor do
-not correctly handle @code{save} and @code{restore} instructions used with
-arguments. They correctly handle them used without arguments. A @code{save}
-instruction used without arguments increments the current window pointer
-but does not allocate a new stack frame. It is assumed that the window
-overflow trap handler will properly handle this case as will interrupt
-handlers.
-@end table
+@item @code{print-asm-header}
+The @code{print-asm-header} function takes no arguments and simply
+prints a banner like:
-These @samp{-m} switches are supported in addition to the above
-on SPARC V9 processors in 64-bit environments.
+@smallexample
+Assembler options
+=================
-@table @gcctabopt
-@item -mlittle-endian
-@opindex mlittle-endian
-Generate code for a processor running in little-endian mode.
+Use "-Wa,OPTION" to pass "OPTION" to the assembler.
+@end smallexample
-@item -m32
-@itemx -m64
-@opindex m32
-@opindex m64
-Generate code for a 32-bit or 64-bit environment.
-The 32-bit environment sets int, long and pointer to 32 bits.
-The 64-bit environment sets int to 32 bits and long and pointer
-to 64 bits.
+It is used to separate compiler options from assembler options
+in the @option{--target-help} output.
+@end table
-@item -mcmodel=medlow
-@opindex mcmodel=medlow
-Generate code for the Medium/Low code model: the program must be linked
-in the low 32 bits of the address space. Pointers are 64 bits.
-Programs can be statically or dynamically linked.
+@item %@{@code{S}@}
+Substitutes the @code{-S} switch, if that switch was given to GCC@.
+If that switch was not specified, this substitutes nothing. Note that
+the leading dash is omitted when specifying this option, and it is
+automatically inserted if the substitution is performed. Thus the spec
+string @samp{%@{foo@}} would match the command-line option @option{-foo}
+and would output the command line option @option{-foo}.
-@item -mcmodel=medmid
-@opindex mcmodel=medmid
-Generate code for the Medium/Middle code model: the program must be linked
-in the low 44 bits of the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
+@item %W@{@code{S}@}
+Like %@{@code{S}@} but mark last argument supplied within as a file to be
+deleted on failure.
-@item -mcmodel=medany
-@opindex mcmodel=medany
-Generate code for the Medium/Anywhere code model: the program may be linked
-anywhere in the address space, the text segment must be less than
-2G bytes, and data segment must be within 2G of the text segment.
-Pointers are 64 bits.
+@item %@{@code{S}*@}
+Substitutes all the switches specified to GCC whose names start
+with @code{-S}, but which also take an argument. This is used for
+switches like @option{-o}, @option{-D}, @option{-I}, etc.
+GCC considers @option{-o foo} as being
+one switch whose names starts with @samp{o}. %@{o*@} would substitute this
+text, including the space. Thus two arguments would be generated.
-@item -mcmodel=embmedany
-@opindex mcmodel=embmedany
-Generate code for the Medium/Anywhere code model for embedded systems:
-assume a 32-bit text and a 32-bit data segment, both starting anywhere
-(determined at link time). Register %g4 points to the base of the
-data segment. Pointers are still 64 bits.
-Programs are statically linked, PIC is not supported.
+@item %@{@code{S}*&@code{T}*@}
+Like %@{@code{S}*@}, but preserve order of @code{S} and @code{T} options
+(the order of @code{S} and @code{T} in the spec is not significant).
+There can be any number of ampersand-separated variables; for each the
+wild card is optional. Useful for CPP as @samp{%@{D*&U*&A*@}}.
-@item -mstack-bias
-@itemx -mno-stack-bias
-@opindex mstack-bias
-@opindex mno-stack-bias
-With @option{-mstack-bias}, GCC assumes that the stack pointer, and
-frame pointer if present, are offset by @minus{}2047 which must be added back
-when making stack frame references.
-Otherwise, assume no such offset is present.
-@end table
+@item %@{@code{S}:@code{X}@}
+Substitutes @code{X}, if the @samp{-S} switch was given to GCC@.
-@node Convex Options
-@subsection Convex Options
-@cindex Convex options
+@item %@{!@code{S}:@code{X}@}
+Substitutes @code{X}, if the @samp{-S} switch was @emph{not} given to GCC@.
-These @samp{-m} options are defined for Convex:
+@item %@{@code{S}*:@code{X}@}
+Substitutes @code{X} if one or more switches whose names start with
+@code{-S} are specified to GCC@. Normally @code{X} is substituted only
+once, no matter how many such switches appeared. However, if @code{%*}
+appears somewhere in @code{X}, then @code{X} will be substituted once
+for each matching switch, with the @code{%*} replaced by the part of
+that switch that matched the @code{*}.
-@table @gcctabopt
-@item -mc1
-@opindex mc1
-Generate output for C1. The code will run on any Convex machine.
-The preprocessor symbol @code{__convex__c1__} is defined.
-
-@item -mc2
-@opindex mc2
-Generate output for C2. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C2.
-The preprocessor symbol @code{__convex_c2__} is defined.
-
-@item -mc32
-@opindex mc32
-Generate output for C32xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C32.
-The preprocessor symbol @code{__convex_c32__} is defined.
-
-@item -mc34
-@opindex mc34
-Generate output for C34xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C34.
-The preprocessor symbol @code{__convex_c34__} is defined.
-
-@item -mc38
-@opindex mc38
-Generate output for C38xx. Uses instructions not available on C1.
-Scheduling and other optimizations are chosen for max performance on C38.
-The preprocessor symbol @code{__convex_c38__} is defined.
-
-@item -margcount
-@opindex margcount
-Generate code which puts an argument count in the word preceding each
-argument list. This is compatible with regular CC, and a few programs
-may need the argument count word. GDB and other source-level debuggers
-do not need it; this info is in the symbol table.
-
-@item -mnoargcount
-@opindex mnoargcount
-Omit the argument count word. This is the default.
-
-@item -mvolatile-cache
-@opindex mvolatile-cache
-Allow volatile references to be cached. This is the default.
-
-@item -mvolatile-nocache
-@opindex mvolatile-nocache
-Volatile references bypass the data cache, going all the way to memory.
-This is only needed for multi-processor code that does not use standard
-synchronization instructions. Making non-volatile references to volatile
-locations will not necessarily work.
+@item %@{.@code{S}:@code{X}@}
+Substitutes @code{X}, if processing a file with suffix @code{S}.
-@item -mlong32
-@opindex mlong32
-Type long is 32 bits, the same as type int. This is the default.
+@item %@{!.@code{S}:@code{X}@}
+Substitutes @code{X}, if @emph{not} processing a file with suffix @code{S}.
-@item -mlong64
-@opindex mlong64
-Type long is 64 bits, the same as type long long. This option is useless,
-because no library support exists for it.
-@end table
+@item %@{,@code{S}:@code{X}@}
+Substitutes @code{X}, if processing a file for language @code{S}.
-@node AMD29K Options
-@subsection AMD29K Options
-@cindex AMD29K options
+@item %@{!,@code{S}:@code{X}@}
+Substitutes @code{X}, if not processing a file for language @code{S}.
-These @samp{-m} options are defined for the AMD Am29000:
+@item %@{@code{S}|@code{P}:@code{X}@}
+Substitutes @code{X} if either @code{-S} or @code{-P} was given to
+GCC@. This may be combined with @samp{!}, @samp{.}, @samp{,}, and
+@code{*} sequences as well, although they have a stronger binding than
+the @samp{|}. If @code{%*} appears in @code{X}, all of the
+alternatives must be starred, and only the first matching alternative
+is substituted.
-@table @gcctabopt
-@item -mdw
-@opindex mdw
-@cindex DW bit (29k)
-Generate code that assumes the @code{DW} bit is set, i.e., that byte and
-halfword operations are directly supported by the hardware. This is the
-default.
+For example, a spec string like this:
-@item -mndw
-@opindex mndw
-Generate code that assumes the @code{DW} bit is not set.
+@smallexample
+%@{.c:-foo@} %@{!.c:-bar@} %@{.c|d:-baz@} %@{!.c|d:-boggle@}
+@end smallexample
-@item -mbw
-@opindex mbw
-@cindex byte writes (29k)
-Generate code that assumes the system supports byte and halfword write
-operations. This is the default.
+will output the following command-line options from the following input
+command-line options:
-@item -mnbw
-@opindex mnbw
-Generate code that assumes the systems does not support byte and
-halfword write operations. @option{-mnbw} implies @option{-mndw}.
-
-@item -msmall
-@opindex msmall
-@cindex memory model (29k)
-Use a small memory model that assumes that all function addresses are
-either within a single 256 KB segment or at an absolute address of less
-than 256k. This allows the @code{call} instruction to be used instead
-of a @code{const}, @code{consth}, @code{calli} sequence.
-
-@item -mnormal
-@opindex mnormal
-Use the normal memory model: Generate @code{call} instructions only when
-calling functions in the same file and @code{calli} instructions
-otherwise. This works if each file occupies less than 256 KB but allows
-the entire executable to be larger than 256 KB@. This is the default.
-
-@item -mlarge
-@opindex mlarge
-Always use @code{calli} instructions. Specify this option if you expect
-a single file to compile into more than 256 KB of code.
-
-@item -m29050
-@opindex m29050
-@cindex processor selection (29k)
-Generate code for the Am29050.
-
-@item -m29000
-@opindex m29000
-Generate code for the Am29000. This is the default.
-
-@item -mkernel-registers
-@opindex mkernel-registers
-@cindex kernel and user registers (29k)
-Generate references to registers @code{gr64-gr95} instead of to
-registers @code{gr96-gr127}. This option can be used when compiling
-kernel code that wants a set of global registers disjoint from that used
-by user-mode code.
-
-Note that when this option is used, register names in @samp{-f} flags
-must use the normal, user-mode, names.
-
-@item -muser-registers
-@opindex muser-registers
-Use the normal set of global registers, @code{gr96-gr127}. This is the
-default.
+@smallexample
+fred.c -foo -baz
+jim.d -bar -boggle
+-d fred.c -foo -baz -boggle
+-d jim.d -bar -baz -boggle
+@end smallexample
-@item -mstack-check
-@itemx -mno-stack-check
-@opindex mstack-check
-@opindex mno-stack-check
-@cindex stack checks (29k)
-Insert (or do not insert) a call to @code{__msp_check} after each stack
-adjustment. This is often used for kernel code.
-
-@item -mstorem-bug
-@itemx -mno-storem-bug
-@opindex mstorem-bug
-@opindex mno-storem-bug
-@cindex storem bug (29k)
-@option{-mstorem-bug} handles 29k processors which cannot handle the
-separation of a mtsrim insn and a storem instruction (most 29000 chips
-to date, but not the 29050).
-
-@item -mno-reuse-arg-regs
-@itemx -mreuse-arg-regs
-@opindex mno-reuse-arg-regs
-@opindex mreuse-arg-regs
-@option{-mno-reuse-arg-regs} tells the compiler to only use incoming argument
-registers for copying out arguments. This helps detect calling a function
-with fewer arguments than it was declared with.
-
-@item -mno-impure-text
-@itemx -mimpure-text
-@opindex mno-impure-text
-@opindex mimpure-text
-@option{-mimpure-text}, used in addition to @option{-shared}, tells the compiler to
-not pass @option{-assert pure-text} to the linker when linking a shared object.
+@item %@{S:X; T:Y; :D@}
+
+If @code{S} was given to GCC, substitutes @code{X}; else if @code{T} was
+given to GCC, substitutes @code{Y}; else substitutes @code{D}. There can
+be as many clauses as you need. This may be combined with @code{.},
+@code{,}, @code{!}, @code{|}, and @code{*} as needed.
-@item -msoft-float
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not part of GCC@.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
-@item -mno-multm
-@opindex mno-multm
-Do not generate multm or multmu instructions. This is useful for some embedded
-systems which do not have trap handlers for these instructions.
@end table
-@node ARM Options
-@subsection ARM Options
-@cindex ARM options
+The conditional text @code{X} in a %@{@code{S}:@code{X}@} or similar
+construct may contain other nested @samp{%} constructs or spaces, or
+even newlines. They are processed as usual, as described above.
+Trailing white space in @code{X} is ignored. White space may also
+appear anywhere on the left side of the colon in these constructs,
+except between @code{.} or @code{*} and the corresponding word.
-These @samp{-m} options are defined for Advanced RISC Machines (ARM)
-architectures:
+The @option{-O}, @option{-f}, @option{-m}, and @option{-W} switches are
+handled specifically in these constructs. If another value of
+@option{-O} or the negated form of a @option{-f}, @option{-m}, or
+@option{-W} switch is found later in the command line, the earlier
+switch value is ignored, except with @{@code{S}*@} where @code{S} is
+just one letter, which passes all matching options.
-@table @gcctabopt
-@item -mapcs-frame
-@opindex mapcs-frame
-Generate a stack frame that is compliant with the ARM Procedure Call
-Standard for all functions, even if this is not strictly necessary for
-correct execution of the code. Specifying @option{-fomit-frame-pointer}
-with this option will cause the stack frames not to be generated for
-leaf functions. The default is @option{-mno-apcs-frame}.
+The character @samp{|} at the beginning of the predicate text is used to
+indicate that a command should be piped to the following command, but
+only if @option{-pipe} is specified.
-@item -mapcs
-@opindex mapcs
-This is a synonym for @option{-mapcs-frame}.
+It is built into GCC which switches take arguments and which do not.
+(You might think it would be useful to generalize this to allow each
+compiler's spec to say which switches take arguments. But this cannot
+be done in a consistent fashion. GCC cannot even decide which input
+files have been specified without knowing which switches take arguments,
+and it must know which input files to compile in order to tell which
+compilers to run).
-@item -mapcs-26
-@opindex mapcs-26
-Generate code for a processor running with a 26-bit program counter,
-and conforming to the function calling standards for the APCS 26-bit
-option. This option replaces the @option{-m2} and @option{-m3} options
-of previous releases of the compiler.
+GCC also knows implicitly that arguments starting in @option{-l} are to be
+treated as compiler output files, and passed to the linker in their
+proper position among the other output files.
-@item -mapcs-32
-@opindex mapcs-32
-Generate code for a processor running with a 32-bit program counter,
-and conforming to the function calling standards for the APCS 32-bit
-option. This option replaces the @option{-m6} option of previous releases
-of the compiler.
+@c man begin OPTIONS
-@ignore
-@c not currently implemented
-@item -mapcs-stack-check
-@opindex mapcs-stack-check
-Generate code to check the amount of stack space available upon entry to
-every function (that actually uses some stack space). If there is
-insufficient space available then either the function
-@samp{__rt_stkovf_split_small} or @samp{__rt_stkovf_split_big} will be
-called, depending upon the amount of stack space required. The run time
-system is required to provide these functions. The default is
-@option{-mno-apcs-stack-check}, since this produces smaller code.
+@node Target Options
+@section Specifying Target Machine and Compiler Version
+@cindex target options
+@cindex cross compiling
+@cindex specifying machine version
+@cindex specifying compiler version and target machine
+@cindex compiler version, specifying
+@cindex target machine, specifying
-@c not currently implemented
-@item -mapcs-float
-@opindex mapcs-float
-Pass floating point arguments using the float point registers. This is
-one of the variants of the APCS@. This option is recommended if the
-target hardware has a floating point unit or if a lot of floating point
-arithmetic is going to be performed by the code. The default is
-@option{-mno-apcs-float}, since integer only code is slightly increased in
-size if @option{-mapcs-float} is used.
+The usual way to run GCC is to run the executable called @file{gcc}, or
+@file{<machine>-gcc} when cross-compiling, or
+@file{<machine>-gcc-<version>} to run a version other than the one that
+was installed last. Sometimes this is inconvenient, so GCC provides
+options that will switch to another cross-compiler or version.
-@c not currently implemented
-@item -mapcs-reentrant
-@opindex mapcs-reentrant
-Generate reentrant, position independent code. The default is
-@option{-mno-apcs-reentrant}.
-@end ignore
+@table @gcctabopt
+@item -b @var{machine}
+@opindex b
+The argument @var{machine} specifies the target machine for compilation.
-@item -mthumb-interwork
-@opindex mthumb-interwork
-Generate code which supports calling between the ARM and Thumb
-instruction sets. Without this option the two instruction sets cannot
-be reliably used inside one program. The default is
-@option{-mno-thumb-interwork}, since slightly larger code is generated
-when @option{-mthumb-interwork} is specified.
+The value to use for @var{machine} is the same as was specified as the
+machine type when configuring GCC as a cross-compiler. For
+example, if a cross-compiler was configured with @samp{configure
+arm-elf}, meaning to compile for an arm processor with elf binaries,
+then you would specify @option{-b arm-elf} to run that cross compiler.
+Because there are other options beginning with @option{-b}, the
+configuration must contain a hyphen, or @option{-b} alone should be one
+argument followed by the configuration in the next argument.
-@item -mno-sched-prolog
-@opindex mno-sched-prolog
-Prevent the reordering of instructions in the function prolog, or the
-merging of those instruction with the instructions in the function's
-body. This means that all functions will start with a recognizable set
-of instructions (or in fact one of a choice from a small set of
-different function prologues), and this information can be used to
-locate the start if functions inside an executable piece of code. The
-default is @option{-msched-prolog}.
+@item -V @var{version}
+@opindex V
+The argument @var{version} specifies which version of GCC to run.
+This is useful when multiple versions are installed. For example,
+@var{version} might be @samp{4.0}, meaning to run GCC version 4.0.
+@end table
-@item -mhard-float
-@opindex mhard-float
-Generate output containing floating point instructions. This is the
-default.
+The @option{-V} and @option{-b} options work by running the
+@file{<machine>-gcc-<version>} executable, so there's no real reason to
+use them if you can just run that directly.
-@item -msoft-float
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not available for all ARM
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation.
+@node Submodel Options
+@section Hardware Models and Configurations
+@cindex submodel options
+@cindex specifying hardware config
+@cindex hardware models and configurations, specifying
+@cindex machine dependent options
-@option{-msoft-float} changes the calling convention in the output file;
-therefore, it is only useful if you compile @emph{all} of a program with
-this option. In particular, you need to compile @file{libgcc.a}, the
-library that comes with GCC, with @option{-msoft-float} in order for
-this to work.
+Earlier we discussed the standard option @option{-b} which chooses among
+different installed compilers for completely different target
+machines, such as VAX vs.@: 68000 vs.@: 80386.
+
+In addition, each of these target machine types can have its own
+special options, starting with @samp{-m}, to choose among various
+hardware models or configurations---for example, 68010 vs 68020,
+floating coprocessor or none. A single installed version of the
+compiler can compile for any model or configuration, according to the
+options specified.
+
+Some configurations of the compiler also support additional special
+options, usually for compatibility with other compilers on the same
+platform.
+
+@c This list is ordered alphanumerically by subsection name.
+@c It should be the same order and spelling as these options are listed
+@c in Machine Dependent Options
+
+@menu
+* ARC Options::
+* ARM Options::
+* AVR Options::
+* Blackfin Options::
+* CRIS Options::
+* CRX Options::
+* Darwin Options::
+* DEC Alpha Options::
+* DEC Alpha/VMS Options::
+* FR30 Options::
+* FRV Options::
+* GNU/Linux Options::
+* H8/300 Options::
+* HPPA Options::
+* i386 and x86-64 Options::
+* i386 and x86-64 Windows Options::
+* IA-64 Options::
+* M32C Options::
+* M32R/D Options::
+* M680x0 Options::
+* M68hc1x Options::
+* MCore Options::
+* MIPS Options::
+* MMIX Options::
+* MN10300 Options::
+* PDP-11 Options::
+* picoChip Options::
+* PowerPC Options::
+* RS/6000 and PowerPC Options::
+* S/390 and zSeries Options::
+* Score Options::
+* SH Options::
+* SPARC Options::
+* SPU Options::
+* System V Options::
+* V850 Options::
+* VAX Options::
+* VxWorks Options::
+* x86-64 Options::
+* Xstormy16 Options::
+* Xtensa Options::
+* zSeries Options::
+@end menu
+
+@node ARC Options
+@subsection ARC Options
+@cindex ARC Options
+
+These options are defined for ARC implementations:
+
+@table @gcctabopt
+@item -EL
+@opindex EL
+Compile code for little endian mode. This is the default.
+
+@item -EB
+@opindex EB
+Compile code for big endian mode.
+
+@item -mmangle-cpu
+@opindex mmangle-cpu
+Prepend the name of the cpu to all public symbol names.
+In multiple-processor systems, there are many ARC variants with different
+instruction and register set characteristics. This flag prevents code
+compiled for one cpu to be linked with code compiled for another.
+No facility exists for handling variants that are ``almost identical''.
+This is an all or nothing option.
+
+@item -mcpu=@var{cpu}
+@opindex mcpu
+Compile code for ARC variant @var{cpu}.
+Which variants are supported depend on the configuration.
+All variants support @option{-mcpu=base}, this is the default.
+
+@item -mtext=@var{text-section}
+@itemx -mdata=@var{data-section}
+@itemx -mrodata=@var{readonly-data-section}
+@opindex mtext
+@opindex mdata
+@opindex mrodata
+Put functions, data, and readonly data in @var{text-section},
+@var{data-section}, and @var{readonly-data-section} respectively
+by default. This can be overridden with the @code{section} attribute.
+@xref{Variable Attributes}.
+
+@item -mfix-cortex-m3-ldrd
+@opindex mfix-cortex-m3-ldrd
+Some Cortex-M3 cores can cause data corruption when @code{ldrd} instructions
+with overlapping destination and base registers are used. This option avoids
+generating these instructions. This option is enabled by default when
+@option{-mcpu=cortex-m3} is specified.
+
+@end table
+
+@node ARM Options
+@subsection ARM Options
+@cindex ARM options
+
+These @samp{-m} options are defined for Advanced RISC Machines (ARM)
+architectures:
+
+@table @gcctabopt
+@item -mabi=@var{name}
+@opindex mabi
+Generate code for the specified ABI@. Permissible values are: @samp{apcs-gnu},
+@samp{atpcs}, @samp{aapcs}, @samp{aapcs-linux} and @samp{iwmmxt}.
+
+@item -mapcs-frame
+@opindex mapcs-frame
+Generate a stack frame that is compliant with the ARM Procedure Call
+Standard for all functions, even if this is not strictly necessary for
+correct execution of the code. Specifying @option{-fomit-frame-pointer}
+with this option will cause the stack frames not to be generated for
+leaf functions. The default is @option{-mno-apcs-frame}.
+
+@item -mapcs
+@opindex mapcs
+This is a synonym for @option{-mapcs-frame}.
+
+@ignore
+@c not currently implemented
+@item -mapcs-stack-check
+@opindex mapcs-stack-check
+Generate code to check the amount of stack space available upon entry to
+every function (that actually uses some stack space). If there is
+insufficient space available then either the function
+@samp{__rt_stkovf_split_small} or @samp{__rt_stkovf_split_big} will be
+called, depending upon the amount of stack space required. The run time
+system is required to provide these functions. The default is
+@option{-mno-apcs-stack-check}, since this produces smaller code.
+
+@c not currently implemented
+@item -mapcs-float
+@opindex mapcs-float
+Pass floating point arguments using the float point registers. This is
+one of the variants of the APCS@. This option is recommended if the
+target hardware has a floating point unit or if a lot of floating point
+arithmetic is going to be performed by the code. The default is
+@option{-mno-apcs-float}, since integer only code is slightly increased in
+size if @option{-mapcs-float} is used.
+
+@c not currently implemented
+@item -mapcs-reentrant
+@opindex mapcs-reentrant
+Generate reentrant, position independent code. The default is
+@option{-mno-apcs-reentrant}.
+@end ignore
+
+@item -mthumb-interwork
+@opindex mthumb-interwork
+Generate code which supports calling between the ARM and Thumb
+instruction sets. Without this option the two instruction sets cannot
+be reliably used inside one program. The default is
+@option{-mno-thumb-interwork}, since slightly larger code is generated
+when @option{-mthumb-interwork} is specified.
+
+@item -mno-sched-prolog
+@opindex mno-sched-prolog
+Prevent the reordering of instructions in the function prolog, or the
+merging of those instruction with the instructions in the function's
+body. This means that all functions will start with a recognizable set
+of instructions (or in fact one of a choice from a small set of
+different function prologues), and this information can be used to
+locate the start if functions inside an executable piece of code. The
+default is @option{-msched-prolog}.
+
+@item -mfloat-abi=@var{name}
+@opindex mfloat-abi
+Specifies which floating-point ABI to use. Permissible values
+are: @samp{soft}, @samp{softfp} and @samp{hard}.
+
+Specifying @samp{soft} causes GCC to generate output containing
+library calls for floating-point operations.
+@samp{softfp} allows the generation of code using hardware floating-point
+instructions, but still uses the soft-float calling conventions.
+@samp{hard} allows generation of floating-point instructions
+and uses FPU-specific calling conventions.
+
+Using @option{-mfloat-abi=hard} with VFP coprocessors is not supported.
+Use @option{-mfloat-abi=softfp} with the appropriate @option{-mfpu} option
+to allow the compiler to generate code that makes use of the hardware
+floating-point capabilities for these CPUs.
+
+The default depends on the specific target configuration. Note that
+the hard-float and soft-float ABIs are not link-compatible; you must
+compile your entire program with the same ABI, and link with a
+compatible set of libraries.
+
+@item -mhard-float
+@opindex mhard-float
+Equivalent to @option{-mfloat-abi=hard}.
+
+@item -msoft-float
+@opindex msoft-float
+Equivalent to @option{-mfloat-abi=soft}.
@item -mlittle-endian
@opindex mlittle-endian
big-endian ARM processors generated by versions of the compiler prior to
2.8.
-@item -malignment-traps
-@opindex malignment-traps
-Generate code that will not trap if the MMU has alignment traps enabled.
-On ARM architectures prior to ARMv4, there were no instructions to
-access half-word objects stored in memory. However, when reading from
-memory a feature of the ARM architecture allows a word load to be used,
-even if the address is unaligned, and the processor core will rotate the
-data as it is being loaded. This option tells the compiler that such
-misaligned accesses will cause a MMU trap and that it should instead
-synthesise the access as a series of byte accesses. The compiler can
-still use word accesses to load half-word data if it knows that the
-address is aligned to a word boundary.
-
-This option is ignored when compiling for ARM architecture 4 or later,
-since these processors have instructions to directly access half-word
-objects in memory.
-
-@item -mno-alignment-traps
-@opindex mno-alignment-traps
-Generate code that assumes that the MMU will not trap unaligned
-accesses. This produces better code when the target instruction set
-does not have half-word memory operations (i.e.@: implementations prior to
-ARMv4).
-
-Note that you cannot use this option to access unaligned word objects,
-since the processor will only fetch one 32-bit aligned object from
-memory.
-
-The default setting for most targets is @option{-mno-alignment-traps}, since
-this produces better code when there are no half-word memory
-instructions available.
-
-@item -mshort-load-bytes
-@itemx -mno-short-load-words
-@opindex mshort-load-bytes
-@opindex mno-short-load-words
-These are deprecated aliases for @option{-malignment-traps}.
-
-@item -mno-short-load-bytes
-@itemx -mshort-load-words
-@opindex mno-short-load-bytes
-@opindex mshort-load-words
-This are deprecated aliases for @option{-mno-alignment-traps}.
-
-@item -mbsd
-@opindex mbsd
-This option only applies to RISC iX@. Emulate the native BSD-mode
-compiler. This is the default if @option{-ansi} is not specified.
-
-@item -mxopen
-@opindex mxopen
-This option only applies to RISC iX@. Emulate the native X/Open-mode
-compiler.
-
-@item -mno-symrename
-@opindex mno-symrename
-This option only applies to RISC iX@. Do not run the assembler
-post-processor, @samp{symrename}, after code has been assembled.
-Normally it is necessary to modify some of the standard symbols in
-preparation for linking with the RISC iX C library; this option
-suppresses this pass. The post-processor is never run when the
-compiler is built for cross-compilation.
-
@item -mcpu=@var{name}
@opindex mcpu
This specifies the name of the target ARM processor. GCC uses this name
@samp{arm620}, @samp{arm7}, @samp{arm7m}, @samp{arm7d}, @samp{arm7dm},
@samp{arm7di}, @samp{arm7dmi}, @samp{arm70}, @samp{arm700},
@samp{arm700i}, @samp{arm710}, @samp{arm710c}, @samp{arm7100},
-@samp{arm7500}, @samp{arm7500fe}, @samp{arm7tdmi}, @samp{arm8},
+@samp{arm720},
+@samp{arm7500}, @samp{arm7500fe}, @samp{arm7tdmi}, @samp{arm7tdmi-s},
+@samp{arm710t}, @samp{arm720t}, @samp{arm740t},
@samp{strongarm}, @samp{strongarm110}, @samp{strongarm1100},
+@samp{strongarm1110},
@samp{arm8}, @samp{arm810}, @samp{arm9}, @samp{arm9e}, @samp{arm920},
-@samp{arm920t}, @samp{arm940t}, @samp{arm9tdmi}, @samp{arm10tdmi},
-@samp{arm1020t}, @samp{xscale}.
-
-@itemx -mtune=@var{name}
+@samp{arm920t}, @samp{arm922t}, @samp{arm946e-s}, @samp{arm966e-s},
+@samp{arm968e-s}, @samp{arm926ej-s}, @samp{arm940t}, @samp{arm9tdmi},
+@samp{arm10tdmi}, @samp{arm1020t}, @samp{arm1026ej-s},
+@samp{arm10e}, @samp{arm1020e}, @samp{arm1022e},
+@samp{arm1136j-s}, @samp{arm1136jf-s}, @samp{mpcore}, @samp{mpcorenovfp},
+@samp{arm1156t2-s}, @samp{arm1176jz-s}, @samp{arm1176jzf-s},
+@samp{cortex-a8}, @samp{cortex-a9},
+@samp{cortex-r4}, @samp{cortex-r4f}, @samp{cortex-m3},
+@samp{cortex-m1},
+@samp{xscale}, @samp{iwmmxt}, @samp{iwmmxt2}, @samp{ep9312}.
+
+@item -mtune=@var{name}
@opindex mtune
This option is very similar to the @option{-mcpu=} option, except that
instead of specifying the actual target processor type, and hence
assembly code. This option can be used in conjunction with or instead
of the @option{-mcpu=} option. Permissible names are: @samp{armv2},
@samp{armv2a}, @samp{armv3}, @samp{armv3m}, @samp{armv4}, @samp{armv4t},
-@samp{armv5}, @samp{armv5t}, @samp{armv5te}.
-
-@item -mfpe=@var{number}
+@samp{armv5}, @samp{armv5t}, @samp{armv5e}, @samp{armv5te},
+@samp{armv6}, @samp{armv6j},
+@samp{armv6t2}, @samp{armv6z}, @samp{armv6zk}, @samp{armv6-m},
+@samp{armv7}, @samp{armv7-a}, @samp{armv7-r}, @samp{armv7-m},
+@samp{iwmmxt}, @samp{iwmmxt2}, @samp{ep9312}.
+
+@item -mfpu=@var{name}
+@itemx -mfpe=@var{number}
@itemx -mfp=@var{number}
+@opindex mfpu
@opindex mfpe
@opindex mfp
-This specifies the version of the floating point emulation available on
-the target. Permissible values are 2 and 3. @option{-mfp=} is a synonym
-for @option{-mfpe=}, for compatibility with older versions of GCC@.
+This specifies what floating point hardware (or hardware emulation) is
+available on the target. Permissible names are: @samp{fpa}, @samp{fpe2},
+@samp{fpe3}, @samp{maverick}, @samp{vfp}, @samp{vfpv3}, @samp{vfpv3-d16} and
+@samp{neon}. @option{-mfp} and @option{-mfpe}
+are synonyms for @option{-mfpu}=@samp{fpe}@var{number}, for compatibility
+with older versions of GCC@.
+
+If @option{-msoft-float} is specified this specifies the format of
+floating point values.
@item -mstructure-size-boundary=@var{n}
@opindex mstructure-size-boundary
The size of all structures and unions will be rounded up to a multiple
-of the number of bits set by this option. Permissible values are 8 and
-32. The default value varies for different toolchains. For the COFF
-targeted toolchain the default value is 8. Specifying the larger number
-can produce faster, more efficient code, but can also increase the size
-of the program. The two values are potentially incompatible. Code
-compiled with one value cannot necessarily expect to work with code or
-libraries compiled with the other value, if they exchange information
-using structures or unions.
+of the number of bits set by this option. Permissible values are 8, 32
+and 64. The default value varies for different toolchains. For the COFF
+targeted toolchain the default value is 8. A value of 64 is only allowed
+if the underlying ABI supports it.
+
+Specifying the larger number can produce faster, more efficient code, but
+can also increase the size of the program. Different values are potentially
+incompatible. Code compiled with one value cannot necessarily expect to
+work with code or libraries compiled with another value, if they exchange
+information using structures or unions.
@item -mabort-on-noreturn
@opindex mabort-on-noreturn
the compiler generates code to handle function calls via function
pointers.
-@item -mnop-fun-dllimport
-@opindex mnop-fun-dllimport
-Disable support for the @code{dllimport} attribute.
-
@item -msingle-pic-base
@opindex msingle-pic-base
Treat the register used for PIC addressing as read-only, rather than
Specify the register to be used for PIC addressing. The default is R10
unless stack-checking is enabled, when R9 is used.
+@item -mcirrus-fix-invalid-insns
+@opindex mcirrus-fix-invalid-insns
+@opindex mno-cirrus-fix-invalid-insns
+Insert NOPs into the instruction stream to in order to work around
+problems with invalid Maverick instruction combinations. This option
+is only valid if the @option{-mcpu=ep9312} option has been used to
+enable generation of instructions for the Cirrus Maverick floating
+point co-processor. This option is not enabled by default, since the
+problem is only present in older Maverick implementations. The default
+can be re-enabled by use of the @option{-mno-cirrus-fix-invalid-insns}
+switch.
+
@item -mpoke-function-name
@opindex mpoke-function-name
Write the name of each function into the text section, directly
@item -mthumb
@opindex mthumb
-Generate code for the 16-bit Thumb instruction set. The default is to
+Generate code for the Thumb instruction set. The default is to
use the 32-bit ARM instruction set.
+This option automatically enables either 16-bit Thumb-1 or
+mixed 16/32-bit Thumb-2 instructions based on the @option{-mcpu=@var{name}}
+and @option{-march=@var{name}} options.
@item -mtpcs-frame
@opindex mtpcs-frame
compiled for interworking or not. There is a small overhead in the cost
of executing a function pointer if this option is enabled.
-@end table
-
-@node MN10200 Options
-@subsection MN10200 Options
-@cindex MN10200 options
-These @option{-m} options are defined for Matsushita MN10200 architectures:
-@table @gcctabopt
-
-@item -mrelax
-@opindex mrelax
-Indicate to the linker that it should perform a relaxation optimization pass
-to shorten branches, calls and absolute memory addresses. This option only
-has an effect when used on the command line for the final link step.
+@item -mtp=@var{name}
+@opindex mtp
+Specify the access model for the thread local storage pointer. The valid
+models are @option{soft}, which generates calls to @code{__aeabi_read_tp},
+@option{cp15}, which fetches the thread pointer from @code{cp15} directly
+(supported in the arm6k architecture), and @option{auto}, which uses the
+best available method for the selected processor. The default setting is
+@option{auto}.
+
+@item -mword-relocations
+@opindex mword-relocations
+Only generate absolute relocations on word sized values (i.e. R_ARM_ABS32).
+This is enabled by default on targets (uClinux, SymbianOS) where the runtime
+loader imposes this restriction, and when @option{-fpic} or @option{-fPIC}
+is specified.
-This option makes symbolic debugging impossible.
@end table
-@node MN10300 Options
-@subsection MN10300 Options
-@cindex MN10300 options
-These @option{-m} options are defined for Matsushita MN10300 architectures:
-
-@table @gcctabopt
-@item -mmult-bug
-@opindex mmult-bug
-Generate code to avoid bugs in the multiply instructions for the MN10300
-processors. This is the default.
+@node AVR Options
+@subsection AVR Options
+@cindex AVR Options
-@item -mno-mult-bug
-@opindex mno-mult-bug
-Do not generate code to avoid bugs in the multiply instructions for the
-MN10300 processors.
+These options are defined for AVR implementations:
-@item -mam33
-@opindex mam33
-Generate code which uses features specific to the AM33 processor.
+@table @gcctabopt
+@item -mmcu=@var{mcu}
+@opindex mmcu
+Specify ATMEL AVR instruction set or MCU type.
-@item -mno-am33
-@opindex mno-am33
-Do not generate code which uses features specific to the AM33 processor. This
-is the default.
+Instruction set avr1 is for the minimal AVR core, not supported by the C
+compiler, only for assembler programs (MCU types: at90s1200, attiny10,
+attiny11, attiny12, attiny15, attiny28).
-@item -mno-crt0
-@opindex mno-crt0
-Do not link in the C run-time initialization object file.
+Instruction set avr2 (default) is for the classic AVR core with up to
+8K program memory space (MCU types: at90s2313, at90s2323, attiny22,
+at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515,
+at90c8534, at90s8535).
-@item -mrelax
-@opindex mrelax
-Indicate to the linker that it should perform a relaxation optimization pass
-to shorten branches, calls and absolute memory addresses. This option only
-has an effect when used on the command line for the final link step.
+Instruction set avr3 is for the classic AVR core with up to 128K program
+memory space (MCU types: atmega103, atmega603, at43usb320, at76c711).
-This option makes symbolic debugging impossible.
-@end table
+Instruction set avr4 is for the enhanced AVR core with up to 8K program
+memory space (MCU types: atmega8, atmega83, atmega85).
+Instruction set avr5 is for the enhanced AVR core with up to 128K program
+memory space (MCU types: atmega16, atmega161, atmega163, atmega32, atmega323,
+atmega64, atmega128, at43usb355, at94k).
-@node M32R/D Options
-@subsection M32R/D Options
-@cindex M32R/D options
-
-These @option{-m} options are defined for Mitsubishi M32R/D architectures:
+@item -msize
+@opindex msize
+Output instruction sizes to the asm file.
-@table @gcctabopt
-@item -m32rx
-@opindex m32rx
-Generate code for the M32R/X@.
+@item -mno-interrupts
+@opindex mno-interrupts
+Generated code is not compatible with hardware interrupts.
+Code size will be smaller.
-@item -m32r
-@opindex m32r
-Generate code for the M32R@. This is the default.
+@item -mcall-prologues
+@opindex mcall-prologues
+Functions prologues/epilogues expanded as call to appropriate
+subroutines. Code size will be smaller.
-@item -mcode-model=small
-@opindex mcode-model=small
-Assume all objects live in the lower 16MB of memory (so that their addresses
-can be loaded with the @code{ld24} instruction), and assume all subroutines
-are reachable with the @code{bl} instruction.
-This is the default.
+@item -mno-tablejump
+@opindex mno-tablejump
+Do not generate tablejump insns which sometimes increase code size.
+The option is now deprecated in favor of the equivalent
+@option{-fno-jump-tables}
-The addressability of a particular object can be set with the
-@code{model} attribute.
+@item -mtiny-stack
+@opindex mtiny-stack
+Change only the low 8 bits of the stack pointer.
-@item -mcode-model=medium
-@opindex mcode-model=medium
-Assume objects may be anywhere in the 32-bit address space (the compiler
-will generate @code{seth/add3} instructions to load their addresses), and
-assume all subroutines are reachable with the @code{bl} instruction.
+@item -mint8
+@opindex mint8
+Assume int to be 8 bit integer. This affects the sizes of all types: A
+char will be 1 byte, an int will be 1 byte, an long will be 2 bytes
+and long long will be 4 bytes. Please note that this option does not
+comply to the C standards, but it will provide you with smaller code
+size.
+@end table
-@item -mcode-model=large
-@opindex mcode-model=large
-Assume objects may be anywhere in the 32-bit address space (the compiler
-will generate @code{seth/add3} instructions to load their addresses), and
-assume subroutines may not be reachable with the @code{bl} instruction
-(the compiler will generate the much slower @code{seth/add3/jl}
-instruction sequence).
+@node Blackfin Options
+@subsection Blackfin Options
+@cindex Blackfin Options
-@item -msdata=none
-@opindex msdata=none
-Disable use of the small data area. Variables will be put into
-one of @samp{.data}, @samp{bss}, or @samp{.rodata} (unless the
-@code{section} attribute has been specified).
-This is the default.
+@table @gcctabopt
+@item -mcpu=@var{cpu}@r{[}-@var{sirevision}@r{]}
+@opindex mcpu=
+Specifies the name of the target Blackfin processor. Currently, @var{cpu}
+can be one of @samp{bf512}, @samp{bf514}, @samp{bf516}, @samp{bf518},
+@samp{bf522}, @samp{bf523}, @samp{bf524}, @samp{bf525}, @samp{bf526},
+@samp{bf527}, @samp{bf531}, @samp{bf532}, @samp{bf533},
+@samp{bf534}, @samp{bf536}, @samp{bf537}, @samp{bf538}, @samp{bf539},
+@samp{bf542}, @samp{bf544}, @samp{bf547}, @samp{bf548}, @samp{bf549},
+@samp{bf561}.
+The optional @var{sirevision} specifies the silicon revision of the target
+Blackfin processor. Any workarounds available for the targeted silicon revision
+will be enabled. If @var{sirevision} is @samp{none}, no workarounds are enabled.
+If @var{sirevision} is @samp{any}, all workarounds for the targeted processor
+will be enabled. The @code{__SILICON_REVISION__} macro is defined to two
+hexadecimal digits representing the major and minor numbers in the silicon
+revision. If @var{sirevision} is @samp{none}, the @code{__SILICON_REVISION__}
+is not defined. If @var{sirevision} is @samp{any}, the
+@code{__SILICON_REVISION__} is defined to be @code{0xffff}.
+If this optional @var{sirevision} is not used, GCC assumes the latest known
+silicon revision of the targeted Blackfin processor.
+
+Support for @samp{bf561} is incomplete. For @samp{bf561},
+Only the processor macro is defined.
+Without this option, @samp{bf532} is used as the processor by default.
+The corresponding predefined processor macros for @var{cpu} is to
+be defined. And for @samp{bfin-elf} toolchain, this causes the hardware BSP
+provided by libgloss to be linked in if @option{-msim} is not given.
-The small data area consists of sections @samp{.sdata} and @samp{.sbss}.
-Objects may be explicitly put in the small data area with the
-@code{section} attribute using one of these sections.
+@item -msim
+@opindex msim
+Specifies that the program will be run on the simulator. This causes
+the simulator BSP provided by libgloss to be linked in. This option
+has effect only for @samp{bfin-elf} toolchain.
+Certain other options, such as @option{-mid-shared-library} and
+@option{-mfdpic}, imply @option{-msim}.
-@item -msdata=sdata
-@opindex msdata=sdata
-Put small global and static data in the small data area, but do not
-generate special code to reference them.
+@item -momit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+Don't keep the frame pointer in a register for leaf functions. This
+avoids the instructions to save, set up and restore frame pointers and
+makes an extra register available in leaf functions. The option
+@option{-fomit-frame-pointer} removes the frame pointer for all functions
+which might make debugging harder.
-@item -msdata=use
-@opindex msdata=use
-Put small global and static data in the small data area, and generate
-special instructions to reference them.
+@item -mspecld-anomaly
+@opindex mspecld-anomaly
+When enabled, the compiler will ensure that the generated code does not
+contain speculative loads after jump instructions. If this option is used,
+@code{__WORKAROUND_SPECULATIVE_LOADS} is defined.
+
+@item -mno-specld-anomaly
+@opindex mno-specld-anomaly
+Don't generate extra code to prevent speculative loads from occurring.
+
+@item -mcsync-anomaly
+@opindex mcsync-anomaly
+When enabled, the compiler will ensure that the generated code does not
+contain CSYNC or SSYNC instructions too soon after conditional branches.
+If this option is used, @code{__WORKAROUND_SPECULATIVE_SYNCS} is defined.
+
+@item -mno-csync-anomaly
+@opindex mno-csync-anomaly
+Don't generate extra code to prevent CSYNC or SSYNC instructions from
+occurring too soon after a conditional branch.
+
+@item -mlow-64k
+@opindex mlow-64k
+When enabled, the compiler is free to take advantage of the knowledge that
+the entire program fits into the low 64k of memory.
+
+@item -mno-low-64k
+@opindex mno-low-64k
+Assume that the program is arbitrarily large. This is the default.
+
+@item -mstack-check-l1
+@opindex mstack-check-l1
+Do stack checking using information placed into L1 scratchpad memory by the
+uClinux kernel.
+
+@item -mid-shared-library
+@opindex mid-shared-library
+Generate code that supports shared libraries via the library ID method.
+This allows for execute in place and shared libraries in an environment
+without virtual memory management. This option implies @option{-fPIC}.
+With a @samp{bfin-elf} target, this option implies @option{-msim}.
+
+@item -mno-id-shared-library
+@opindex mno-id-shared-library
+Generate code that doesn't assume ID based shared libraries are being used.
+This is the default.
-@item -G @var{num}
-@opindex G
-@cindex smaller data references
-Put global and static objects less than or equal to @var{num} bytes
-into the small data or bss sections instead of the normal data or bss
-sections. The default value of @var{num} is 8.
-The @option{-msdata} option must be set to one of @samp{sdata} or @samp{use}
-for this option to have any effect.
+@item -mleaf-id-shared-library
+@opindex mleaf-id-shared-library
+Generate code that supports shared libraries via the library ID method,
+but assumes that this library or executable won't link against any other
+ID shared libraries. That allows the compiler to use faster code for jumps
+and calls.
+
+@item -mno-leaf-id-shared-library
+@opindex mno-leaf-id-shared-library
+Do not assume that the code being compiled won't link against any ID shared
+libraries. Slower code will be generated for jump and call insns.
+
+@item -mshared-library-id=n
+@opindex mshared-library-id
+Specified the identification number of the ID based shared library being
+compiled. Specifying a value of 0 will generate more compact code, specifying
+other values will force the allocation of that number to the current
+library but is no more space or time efficient than omitting this option.
+
+@item -msep-data
+@opindex msep-data
+Generate code that allows the data segment to be located in a different
+area of memory from the text segment. This allows for execute in place in
+an environment without virtual memory management by eliminating relocations
+against the text section.
+
+@item -mno-sep-data
+@opindex mno-sep-data
+Generate code that assumes that the data segment follows the text segment.
+This is the default.
-All modules should be compiled with the same @option{-G @var{num}} value.
-Compiling with different values of @var{num} may or may not work; if it
-doesn't the linker will give an error message---incorrect code will not be
-generated.
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Tells the compiler to perform function calls by first loading the
+address of the function into a register and then performing a subroutine
+call on this register. This switch is needed if the target function
+will lie outside of the 24 bit addressing range of the offset based
+version of subroutine call instruction.
+This feature is not enabled by default. Specifying
+@option{-mno-long-calls} will restore the default behavior. Note these
+switches have no effect on how the compiler generates code to handle
+function calls via function pointers.
+
+@item -mfast-fp
+@opindex mfast-fp
+Link with the fast floating-point library. This library relaxes some of
+the IEEE floating-point standard's rules for checking inputs against
+Not-a-Number (NAN), in the interest of performance.
+
+@item -minline-plt
+@opindex minline-plt
+Enable inlining of PLT entries in function calls to functions that are
+not known to bind locally. It has no effect without @option{-mfdpic}.
+
+@item -mmulticore
+@opindex mmulticore
+Build standalone application for multicore Blackfin processor. Proper
+start files and link scripts will be used to support multicore.
+This option defines @code{__BFIN_MULTICORE}. It can only be used with
+@option{-mcpu=bf561@r{[}-@var{sirevision}@r{]}}. It can be used with
+@option{-mcorea} or @option{-mcoreb}. If it's used without
+@option{-mcorea} or @option{-mcoreb}, single application/dual core
+programming model is used. In this model, the main function of Core B
+should be named as coreb_main. If it's used with @option{-mcorea} or
+@option{-mcoreb}, one application per core programming model is used.
+If this option is not used, single core application programming
+model is used.
+
+@item -mcorea
+@opindex mcorea
+Build standalone application for Core A of BF561 when using
+one application per core programming model. Proper start files
+and link scripts will be used to support Core A. This option
+defines @code{__BFIN_COREA}. It must be used with @option{-mmulticore}.
+
+@item -mcoreb
+@opindex mcoreb
+Build standalone application for Core B of BF561 when using
+one application per core programming model. Proper start files
+and link scripts will be used to support Core B. This option
+defines @code{__BFIN_COREB}. When this option is used, coreb_main
+should be used instead of main. It must be used with
+@option{-mmulticore}.
+
+@item -msdram
+@opindex msdram
+Build standalone application for SDRAM. Proper start files and
+link scripts will be used to put the application into SDRAM.
+Loader should initialize SDRAM before loading the application
+into SDRAM. This option defines @code{__BFIN_SDRAM}.
+
+@item -micplb
+@opindex micplb
+Assume that ICPLBs are enabled at runtime. This has an effect on certain
+anomaly workarounds. For Linux targets, the default is to assume ICPLBs
+are enabled; for standalone applications the default is off.
@end table
-@node M88K Options
-@subsection M88K Options
-@cindex M88k options
+@node CRIS Options
+@subsection CRIS Options
+@cindex CRIS Options
-These @samp{-m} options are defined for Motorola 88k architectures:
+These options are defined specifically for the CRIS ports.
@table @gcctabopt
-@item -m88000
-@opindex m88000
-Generate code that works well on both the m88100 and the
-m88110.
-
-@item -m88100
-@opindex m88100
-Generate code that works best for the m88100, but that also
-runs on the m88110.
-
-@item -m88110
-@opindex m88110
-Generate code that works best for the m88110, and may not run
-on the m88100.
-
-@item -mbig-pic
-@opindex mbig-pic
-Obsolete option to be removed from the next revision.
-Use @option{-fPIC}.
-
-@item -midentify-revision
-@opindex midentify-revision
-@cindex identifying source, compiler (88k)
-Include an @code{ident} directive in the assembler output recording the
-source file name, compiler name and version, timestamp, and compilation
-flags used.
-
-@item -mno-underscores
-@opindex mno-underscores
-@cindex underscores, avoiding (88k)
-In assembler output, emit symbol names without adding an underscore
-character at the beginning of each name. The default is to use an
-underscore as prefix on each name.
-
-@item -mocs-debug-info
-@itemx -mno-ocs-debug-info
-@opindex mocs-debug-info
-@opindex mno-ocs-debug-info
-@cindex OCS (88k)
-@cindex debugging, 88k OCS
-Include (or omit) additional debugging information (about registers used
-in each stack frame) as specified in the 88open Object Compatibility
-Standard, ``OCS''@. This extra information allows debugging of code that
-has had the frame pointer eliminated. The default for DG/UX, SVr4, and
-Delta 88 SVr3.2 is to include this information; other 88k configurations
-omit this information by default.
-
-@item -mocs-frame-position
-@opindex mocs-frame-position
-@cindex register positions in frame (88k)
-When emitting COFF debugging information for automatic variables and
-parameters stored on the stack, use the offset from the canonical frame
-address, which is the stack pointer (register 31) on entry to the
-function. The DG/UX, SVr4, Delta88 SVr3.2, and BCS configurations use
-@option{-mocs-frame-position}; other 88k configurations have the default
-@option{-mno-ocs-frame-position}.
-
-@item -mno-ocs-frame-position
-@opindex mno-ocs-frame-position
-@cindex register positions in frame (88k)
-When emitting COFF debugging information for automatic variables and
-parameters stored on the stack, use the offset from the frame pointer
-register (register 30). When this option is in effect, the frame
-pointer is not eliminated when debugging information is selected by the
--g switch.
-
-@item -moptimize-arg-area
-@opindex moptimize-arg-area
-@cindex arguments in frame (88k)
-Save space by reorganizing the stack frame. This option generates code
-that does not agree with the 88open specifications, but uses less
-memory.
-
-@itemx -mno-optimize-arg-area
-@opindex mno-optimize-arg-area
-Do not reorganize the stack frame to save space. This is the default.
-The generated conforms to the specification, but uses more memory.
-
-@item -mshort-data-@var{num}
-@opindex mshort-data
-@cindex smaller data references (88k)
-@cindex r0-relative references (88k)
-Generate smaller data references by making them relative to @code{r0},
-which allows loading a value using a single instruction (rather than the
-usual two). You control which data references are affected by
-specifying @var{num} with this option. For example, if you specify
-@option{-mshort-data-512}, then the data references affected are those
-involving displacements of less than 512 bytes.
-@option{-mshort-data-@var{num}} is not effective for @var{num} greater
-than 64k.
+@item -march=@var{architecture-type}
+@itemx -mcpu=@var{architecture-type}
+@opindex march
+@opindex mcpu
+Generate code for the specified architecture. The choices for
+@var{architecture-type} are @samp{v3}, @samp{v8} and @samp{v10} for
+respectively ETRAX@w{ }4, ETRAX@w{ }100, and ETRAX@w{ }100@w{ }LX@.
+Default is @samp{v0} except for cris-axis-linux-gnu, where the default is
+@samp{v10}.
-@item -mserialize-volatile
-@opindex mserialize-volatile
-@itemx -mno-serialize-volatile
-@opindex mno-serialize-volatile
-@cindex sequential consistency on 88k
-Do, or don't, generate code to guarantee sequential consistency
-of volatile memory references. By default, consistency is
-guaranteed.
-
-The order of memory references made by the MC88110 processor does
-not always match the order of the instructions requesting those
-references. In particular, a load instruction may execute before
-a preceding store instruction. Such reordering violates
-sequential consistency of volatile memory references, when there
-are multiple processors. When consistency must be guaranteed,
-GCC generates special instructions, as needed, to force
-execution in the proper order.
-
-The MC88100 processor does not reorder memory references and so
-always provides sequential consistency. However, by default, GCC
-generates the special instructions to guarantee consistency
-even when you use @option{-m88100}, so that the code may be run on an
-MC88110 processor. If you intend to run your code only on the
-MC88100 processor, you may use @option{-mno-serialize-volatile}.
-
-The extra code generated to guarantee consistency may affect the
-performance of your application. If you know that you can safely
-forgo this guarantee, you may use @option{-mno-serialize-volatile}.
-
-@item -msvr4
-@itemx -msvr3
-@opindex msvr4
-@opindex msvr3
-@cindex assembler syntax, 88k
-@cindex SVr4
-Turn on (@option{-msvr4}) or off (@option{-msvr3}) compiler extensions
-related to System V release 4 (SVr4). This controls the following:
+@item -mtune=@var{architecture-type}
+@opindex mtune
+Tune to @var{architecture-type} everything applicable about the generated
+code, except for the ABI and the set of available instructions. The
+choices for @var{architecture-type} are the same as for
+@option{-march=@var{architecture-type}}.
-@enumerate
-@item
-Which variant of the assembler syntax to emit.
-@item
-@option{-msvr4} makes the C preprocessor recognize @samp{#pragma weak}
-that is used on System V release 4.
-@item
-@option{-msvr4} makes GCC issue additional declaration directives used in
-SVr4.
-@end enumerate
+@item -mmax-stack-frame=@var{n}
+@opindex mmax-stack-frame
+Warn when the stack frame of a function exceeds @var{n} bytes.
-@option{-msvr4} is the default for the m88k-motorola-sysv4 and
-m88k-dg-dgux m88k configurations. @option{-msvr3} is the default for all
-other m88k configurations.
+@item -metrax4
+@itemx -metrax100
+@opindex metrax4
+@opindex metrax100
+The options @option{-metrax4} and @option{-metrax100} are synonyms for
+@option{-march=v3} and @option{-march=v8} respectively.
-@item -mversion-03.00
-@opindex mversion-03.00
-This option is obsolete, and is ignored.
-@c ??? which asm syntax better for GAS? option there too?
+@item -mmul-bug-workaround
+@itemx -mno-mul-bug-workaround
+@opindex mmul-bug-workaround
+@opindex mno-mul-bug-workaround
+Work around a bug in the @code{muls} and @code{mulu} instructions for CPU
+models where it applies. This option is active by default.
-@item -mno-check-zero-division
-@itemx -mcheck-zero-division
-@opindex mno-check-zero-division
-@opindex mcheck-zero-division
-@cindex zero division on 88k
-Do, or don't, generate code to guarantee that integer division by
-zero will be detected. By default, detection is guaranteed.
-
-Some models of the MC88100 processor fail to trap upon integer
-division by zero under certain conditions. By default, when
-compiling code that might be run on such a processor, GCC
-generates code that explicitly checks for zero-valued divisors
-and traps with exception number 503 when one is detected. Use of
-@option{-mno-check-zero-division} suppresses such checking for code
-generated to run on an MC88100 processor.
-
-GCC assumes that the MC88110 processor correctly detects all instances
-of integer division by zero. When @option{-m88110} is specified, no
-explicit checks for zero-valued divisors are generated, and both
-@option{-mcheck-zero-division} and @option{-mno-check-zero-division} are
-ignored.
+@item -mpdebug
+@opindex mpdebug
+Enable CRIS-specific verbose debug-related information in the assembly
+code. This option also has the effect to turn off the @samp{#NO_APP}
+formatted-code indicator to the assembler at the beginning of the
+assembly file.
-@item -muse-div-instruction
-@opindex muse-div-instruction
-@cindex divide instruction, 88k
-Use the div instruction for signed integer division on the
-MC88100 processor. By default, the div instruction is not used.
-
-On the MC88100 processor the signed integer division instruction
-div) traps to the operating system on a negative operand. The
-operating system transparently completes the operation, but at a
-large cost in execution time. By default, when compiling code
-that might be run on an MC88100 processor, GCC emulates signed
-integer division using the unsigned integer division instruction
-divu), thereby avoiding the large penalty of a trap to the
-operating system. Such emulation has its own, smaller, execution
-cost in both time and space. To the extent that your code's
-important signed integer division operations are performed on two
-nonnegative operands, it may be desirable to use the div
-instruction directly.
-
-On the MC88110 processor the div instruction (also known as the
-divs instruction) processes negative operands without trapping to
-the operating system. When @option{-m88110} is specified,
-@option{-muse-div-instruction} is ignored, and the div instruction is used
-for signed integer division.
-
-Note that the result of dividing @code{INT_MIN} by @minus{}1 is undefined. In
-particular, the behavior of such a division with and without
-@option{-muse-div-instruction} may differ.
-
-@item -mtrap-large-shift
-@itemx -mhandle-large-shift
-@opindex mtrap-large-shift
-@opindex mhandle-large-shift
-@cindex bit shift overflow (88k)
-@cindex large bit shifts (88k)
-Include code to detect bit-shifts of more than 31 bits; respectively,
-trap such shifts or emit code to handle them properly. By default GCC
-makes no special provision for large bit shifts.
-
-@item -mwarn-passed-structs
-@opindex mwarn-passed-structs
-@cindex structure passing (88k)
-Warn when a function passes a struct as an argument or result.
-Structure-passing conventions have changed during the evolution of the C
-language, and are often the source of portability problems. By default,
-GCC issues no such warning.
-@end table
+@item -mcc-init
+@opindex mcc-init
+Do not use condition-code results from previous instruction; always emit
+compare and test instructions before use of condition codes.
-@c break page here to avoid unsightly interparagraph stretch.
-@c -zw, 2001-8-17
-@page
+@item -mno-side-effects
+@opindex mno-side-effects
+Do not emit instructions with side-effects in addressing modes other than
+post-increment.
-@node RS/6000 and PowerPC Options
-@subsection IBM RS/6000 and PowerPC Options
-@cindex RS/6000 and PowerPC Options
-@cindex IBM RS/6000 and PowerPC Options
+@item -mstack-align
+@itemx -mno-stack-align
+@itemx -mdata-align
+@itemx -mno-data-align
+@itemx -mconst-align
+@itemx -mno-const-align
+@opindex mstack-align
+@opindex mno-stack-align
+@opindex mdata-align
+@opindex mno-data-align
+@opindex mconst-align
+@opindex mno-const-align
+These options (no-options) arranges (eliminate arrangements) for the
+stack-frame, individual data and constants to be aligned for the maximum
+single data access size for the chosen CPU model. The default is to
+arrange for 32-bit alignment. ABI details such as structure layout are
+not affected by these options.
-These @samp{-m} options are defined for the IBM RS/6000 and PowerPC:
-@table @gcctabopt
-@item -mpower
-@itemx -mno-power
-@itemx -mpower2
-@itemx -mno-power2
-@itemx -mpowerpc
-@itemx -mno-powerpc
-@itemx -mpowerpc-gpopt
-@itemx -mno-powerpc-gpopt
-@itemx -mpowerpc-gfxopt
-@itemx -mno-powerpc-gfxopt
-@itemx -mpowerpc64
-@itemx -mno-powerpc64
-@opindex mpower
-@opindex mno-power
-@opindex mpower2
-@opindex mno-power2
-@opindex mpowerpc
-@opindex mno-powerpc
-@opindex mpowerpc-gpopt
-@opindex mno-powerpc-gpopt
-@opindex mpowerpc-gfxopt
-@opindex mno-powerpc-gfxopt
-@opindex mpowerpc64
-@opindex mno-powerpc64
-GCC supports two related instruction set architectures for the
-RS/6000 and PowerPC@. The @dfn{POWER} instruction set are those
-instructions supported by the @samp{rios} chip set used in the original
-RS/6000 systems and the @dfn{PowerPC} instruction set is the
-architecture of the Motorola MPC5xx, MPC6xx, MPC8xx microprocessors, and
-the IBM 4xx microprocessors.
+@item -m32-bit
+@itemx -m16-bit
+@itemx -m8-bit
+@opindex m32-bit
+@opindex m16-bit
+@opindex m8-bit
+Similar to the stack- data- and const-align options above, these options
+arrange for stack-frame, writable data and constants to all be 32-bit,
+16-bit or 8-bit aligned. The default is 32-bit alignment.
-Neither architecture is a subset of the other. However there is a
-large common subset of instructions supported by both. An MQ
-register is included in processors supporting the POWER architecture.
+@item -mno-prologue-epilogue
+@itemx -mprologue-epilogue
+@opindex mno-prologue-epilogue
+@opindex mprologue-epilogue
+With @option{-mno-prologue-epilogue}, the normal function prologue and
+epilogue that sets up the stack-frame are omitted and no return
+instructions or return sequences are generated in the code. Use this
+option only together with visual inspection of the compiled code: no
+warnings or errors are generated when call-saved registers must be saved,
+or storage for local variable needs to be allocated.
-You use these options to specify which instructions are available on the
-processor you are using. The default value of these options is
-determined when configuring GCC@. Specifying the
-@option{-mcpu=@var{cpu_type}} overrides the specification of these
-options. We recommend you use the @option{-mcpu=@var{cpu_type}} option
-rather than the options listed above.
+@item -mno-gotplt
+@itemx -mgotplt
+@opindex mno-gotplt
+@opindex mgotplt
+With @option{-fpic} and @option{-fPIC}, don't generate (do generate)
+instruction sequences that load addresses for functions from the PLT part
+of the GOT rather than (traditional on other architectures) calls to the
+PLT@. The default is @option{-mgotplt}.
-The @option{-mpower} option allows GCC to generate instructions that
-are found only in the POWER architecture and to use the MQ register.
-Specifying @option{-mpower2} implies @option{-power} and also allows GCC
-to generate instructions that are present in the POWER2 architecture but
-not the original POWER architecture.
+@item -melf
+@opindex melf
+Legacy no-op option only recognized with the cris-axis-elf and
+cris-axis-linux-gnu targets.
-The @option{-mpowerpc} option allows GCC to generate instructions that
-are found only in the 32-bit subset of the PowerPC architecture.
-Specifying @option{-mpowerpc-gpopt} implies @option{-mpowerpc} and also allows
-GCC to use the optional PowerPC architecture instructions in the
-General Purpose group, including floating-point square root. Specifying
-@option{-mpowerpc-gfxopt} implies @option{-mpowerpc} and also allows GCC to
-use the optional PowerPC architecture instructions in the Graphics
-group, including floating-point select.
+@item -mlinux
+@opindex mlinux
+Legacy no-op option only recognized with the cris-axis-linux-gnu target.
-The @option{-mpowerpc64} option allows GCC to generate the additional
-64-bit instructions that are found in the full PowerPC64 architecture
-and to treat GPRs as 64-bit, doubleword quantities. GCC defaults to
-@option{-mno-powerpc64}.
+@item -sim
+@opindex sim
+This option, recognized for the cris-axis-elf arranges
+to link with input-output functions from a simulator library. Code,
+initialized data and zero-initialized data are allocated consecutively.
+
+@item -sim2
+@opindex sim2
+Like @option{-sim}, but pass linker options to locate initialized data at
+0x40000000 and zero-initialized data at 0x80000000.
+@end table
+
+@node CRX Options
+@subsection CRX Options
+@cindex CRX Options
+
+These options are defined specifically for the CRX ports.
+
+@table @gcctabopt
+
+@item -mmac
+@opindex mmac
+Enable the use of multiply-accumulate instructions. Disabled by default.
+
+@item -mpush-args
+@opindex mpush-args
+Push instructions will be used to pass outgoing arguments when functions
+are called. Enabled by default.
+@end table
+
+@node Darwin Options
+@subsection Darwin Options
+@cindex Darwin options
+
+These options are defined for all architectures running the Darwin operating
+system.
+
+FSF GCC on Darwin does not create ``fat'' object files; it will create
+an object file for the single architecture that it was built to
+target. Apple's GCC on Darwin does create ``fat'' files if multiple
+@option{-arch} options are used; it does so by running the compiler or
+linker multiple times and joining the results together with
+@file{lipo}.
+
+The subtype of the file created (like @samp{ppc7400} or @samp{ppc970} or
+@samp{i686}) is determined by the flags that specify the ISA
+that GCC is targetting, like @option{-mcpu} or @option{-march}. The
+@option{-force_cpusubtype_ALL} option can be used to override this.
+
+The Darwin tools vary in their behavior when presented with an ISA
+mismatch. The assembler, @file{as}, will only permit instructions to
+be used that are valid for the subtype of the file it is generating,
+so you cannot put 64-bit instructions in an @samp{ppc750} object file.
+The linker for shared libraries, @file{/usr/bin/libtool}, will fail
+and print an error if asked to create a shared library with a less
+restrictive subtype than its input files (for instance, trying to put
+a @samp{ppc970} object file in a @samp{ppc7400} library). The linker
+for executables, @file{ld}, will quietly give the executable the most
+restrictive subtype of any of its input files.
+
+@table @gcctabopt
+@item -F@var{dir}
+@opindex F
+Add the framework directory @var{dir} to the head of the list of
+directories to be searched for header files. These directories are
+interleaved with those specified by @option{-I} options and are
+scanned in a left-to-right order.
+
+A framework directory is a directory with frameworks in it. A
+framework is a directory with a @samp{"Headers"} and/or
+@samp{"PrivateHeaders"} directory contained directly in it that ends
+in @samp{".framework"}. The name of a framework is the name of this
+directory excluding the @samp{".framework"}. Headers associated with
+the framework are found in one of those two directories, with
+@samp{"Headers"} being searched first. A subframework is a framework
+directory that is in a framework's @samp{"Frameworks"} directory.
+Includes of subframework headers can only appear in a header of a
+framework that contains the subframework, or in a sibling subframework
+header. Two subframeworks are siblings if they occur in the same
+framework. A subframework should not have the same name as a
+framework, a warning will be issued if this is violated. Currently a
+subframework cannot have subframeworks, in the future, the mechanism
+may be extended to support this. The standard frameworks can be found
+in @samp{"/System/Library/Frameworks"} and
+@samp{"/Library/Frameworks"}. An example include looks like
+@code{#include <Framework/header.h>}, where @samp{Framework} denotes
+the name of the framework and header.h is found in the
+@samp{"PrivateHeaders"} or @samp{"Headers"} directory.
+
+@item -iframework@var{dir}
+@opindex iframework
+Like @option{-F} except the directory is a treated as a system
+directory. The main difference between this @option{-iframework} and
+@option{-F} is that with @option{-iframework} the compiler does not
+warn about constructs contained within header files found via
+@var{dir}. This option is valid only for the C family of languages.
+
+@item -gused
+@opindex gused
+Emit debugging information for symbols that are used. For STABS
+debugging format, this enables @option{-feliminate-unused-debug-symbols}.
+This is by default ON@.
+
+@item -gfull
+@opindex gfull
+Emit debugging information for all symbols and types.
+
+@item -mmacosx-version-min=@var{version}
+The earliest version of MacOS X that this executable will run on
+is @var{version}. Typical values of @var{version} include @code{10.1},
+@code{10.2}, and @code{10.3.9}.
+
+If the compiler was built to use the system's headers by default,
+then the default for this option is the system version on which the
+compiler is running, otherwise the default is to make choices which
+are compatible with as many systems and code bases as possible.
+
+@item -mkernel
+@opindex mkernel
+Enable kernel development mode. The @option{-mkernel} option sets
+@option{-static}, @option{-fno-common}, @option{-fno-cxa-atexit},
+@option{-fno-exceptions}, @option{-fno-non-call-exceptions},
+@option{-fapple-kext}, @option{-fno-weak} and @option{-fno-rtti} where
+applicable. This mode also sets @option{-mno-altivec},
+@option{-msoft-float}, @option{-fno-builtin} and
+@option{-mlong-branch} for PowerPC targets.
+
+@item -mone-byte-bool
+@opindex mone-byte-bool
+Override the defaults for @samp{bool} so that @samp{sizeof(bool)==1}.
+By default @samp{sizeof(bool)} is @samp{4} when compiling for
+Darwin/PowerPC and @samp{1} when compiling for Darwin/x86, so this
+option has no effect on x86.
+
+@strong{Warning:} The @option{-mone-byte-bool} switch causes GCC
+to generate code that is not binary compatible with code generated
+without that switch. Using this switch may require recompiling all
+other modules in a program, including system libraries. Use this
+switch to conform to a non-default data model.
+
+@item -mfix-and-continue
+@itemx -ffix-and-continue
+@itemx -findirect-data
+@opindex mfix-and-continue
+@opindex ffix-and-continue
+@opindex findirect-data
+Generate code suitable for fast turn around development. Needed to
+enable gdb to dynamically load @code{.o} files into already running
+programs. @option{-findirect-data} and @option{-ffix-and-continue}
+are provided for backwards compatibility.
+
+@item -all_load
+@opindex all_load
+Loads all members of static archive libraries.
+See man ld(1) for more information.
+
+@item -arch_errors_fatal
+@opindex arch_errors_fatal
+Cause the errors having to do with files that have the wrong architecture
+to be fatal.
+
+@item -bind_at_load
+@opindex bind_at_load
+Causes the output file to be marked such that the dynamic linker will
+bind all undefined references when the file is loaded or launched.
+
+@item -bundle
+@opindex bundle
+Produce a Mach-o bundle format file.
+See man ld(1) for more information.
+
+@item -bundle_loader @var{executable}
+@opindex bundle_loader
+This option specifies the @var{executable} that will be loading the build
+output file being linked. See man ld(1) for more information.
+
+@item -dynamiclib
+@opindex dynamiclib
+When passed this option, GCC will produce a dynamic library instead of
+an executable when linking, using the Darwin @file{libtool} command.
+
+@item -force_cpusubtype_ALL
+@opindex force_cpusubtype_ALL
+This causes GCC's output file to have the @var{ALL} subtype, instead of
+one controlled by the @option{-mcpu} or @option{-march} option.
+
+@item -allowable_client @var{client_name}
+@itemx -client_name
+@itemx -compatibility_version
+@itemx -current_version
+@itemx -dead_strip
+@itemx -dependency-file
+@itemx -dylib_file
+@itemx -dylinker_install_name
+@itemx -dynamic
+@itemx -exported_symbols_list
+@itemx -filelist
+@itemx -flat_namespace
+@itemx -force_flat_namespace
+@itemx -headerpad_max_install_names
+@itemx -image_base
+@itemx -init
+@itemx -install_name
+@itemx -keep_private_externs
+@itemx -multi_module
+@itemx -multiply_defined
+@itemx -multiply_defined_unused
+@itemx -noall_load
+@itemx -no_dead_strip_inits_and_terms
+@itemx -nofixprebinding
+@itemx -nomultidefs
+@itemx -noprebind
+@itemx -noseglinkedit
+@itemx -pagezero_size
+@itemx -prebind
+@itemx -prebind_all_twolevel_modules
+@itemx -private_bundle
+@itemx -read_only_relocs
+@itemx -sectalign
+@itemx -sectobjectsymbols
+@itemx -whyload
+@itemx -seg1addr
+@itemx -sectcreate
+@itemx -sectobjectsymbols
+@itemx -sectorder
+@itemx -segaddr
+@itemx -segs_read_only_addr
+@itemx -segs_read_write_addr
+@itemx -seg_addr_table
+@itemx -seg_addr_table_filename
+@itemx -seglinkedit
+@itemx -segprot
+@itemx -segs_read_only_addr
+@itemx -segs_read_write_addr
+@itemx -single_module
+@itemx -static
+@itemx -sub_library
+@itemx -sub_umbrella
+@itemx -twolevel_namespace
+@itemx -umbrella
+@itemx -undefined
+@itemx -unexported_symbols_list
+@itemx -weak_reference_mismatches
+@itemx -whatsloaded
+@opindex allowable_client
+@opindex client_name
+@opindex compatibility_version
+@opindex current_version
+@opindex dead_strip
+@opindex dependency-file
+@opindex dylib_file
+@opindex dylinker_install_name
+@opindex dynamic
+@opindex exported_symbols_list
+@opindex filelist
+@opindex flat_namespace
+@opindex force_flat_namespace
+@opindex headerpad_max_install_names
+@opindex image_base
+@opindex init
+@opindex install_name
+@opindex keep_private_externs
+@opindex multi_module
+@opindex multiply_defined
+@opindex multiply_defined_unused
+@opindex noall_load
+@opindex no_dead_strip_inits_and_terms
+@opindex nofixprebinding
+@opindex nomultidefs
+@opindex noprebind
+@opindex noseglinkedit
+@opindex pagezero_size
+@opindex prebind
+@opindex prebind_all_twolevel_modules
+@opindex private_bundle
+@opindex read_only_relocs
+@opindex sectalign
+@opindex sectobjectsymbols
+@opindex whyload
+@opindex seg1addr
+@opindex sectcreate
+@opindex sectobjectsymbols
+@opindex sectorder
+@opindex segaddr
+@opindex segs_read_only_addr
+@opindex segs_read_write_addr
+@opindex seg_addr_table
+@opindex seg_addr_table_filename
+@opindex seglinkedit
+@opindex segprot
+@opindex segs_read_only_addr
+@opindex segs_read_write_addr
+@opindex single_module
+@opindex static
+@opindex sub_library
+@opindex sub_umbrella
+@opindex twolevel_namespace
+@opindex umbrella
+@opindex undefined
+@opindex unexported_symbols_list
+@opindex weak_reference_mismatches
+@opindex whatsloaded
+These options are passed to the Darwin linker. The Darwin linker man page
+describes them in detail.
+@end table
+
+@node DEC Alpha Options
+@subsection DEC Alpha Options
+
+These @samp{-m} options are defined for the DEC Alpha implementations:
+
+@table @gcctabopt
+@item -mno-soft-float
+@itemx -msoft-float
+@opindex mno-soft-float
+@opindex msoft-float
+Use (do not use) the hardware floating-point instructions for
+floating-point operations. When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} will be used to perform floating-point
+operations. Unless they are replaced by routines that emulate the
+floating-point operations, or compiled in such a way as to call such
+emulations routines, these routines will issue floating-point
+operations. If you are compiling for an Alpha without floating-point
+operations, you must ensure that the library is built so as not to call
+them.
+
+Note that Alpha implementations without floating-point operations are
+required to have floating-point registers.
+
+@item -mfp-reg
+@itemx -mno-fp-regs
+@opindex mfp-reg
+@opindex mno-fp-regs
+Generate code that uses (does not use) the floating-point register set.
+@option{-mno-fp-regs} implies @option{-msoft-float}. If the floating-point
+register set is not used, floating point operands are passed in integer
+registers as if they were integers and floating-point results are passed
+in @code{$0} instead of @code{$f0}. This is a non-standard calling sequence,
+so any function with a floating-point argument or return value called by code
+compiled with @option{-mno-fp-regs} must also be compiled with that
+option.
+
+A typical use of this option is building a kernel that does not use,
+and hence need not save and restore, any floating-point registers.
+
+@item -mieee
+@opindex mieee
+The Alpha architecture implements floating-point hardware optimized for
+maximum performance. It is mostly compliant with the IEEE floating
+point standard. However, for full compliance, software assistance is
+required. This option generates code fully IEEE compliant code
+@emph{except} that the @var{inexact-flag} is not maintained (see below).
+If this option is turned on, the preprocessor macro @code{_IEEE_FP} is
+defined during compilation. The resulting code is less efficient but is
+able to correctly support denormalized numbers and exceptional IEEE
+values such as not-a-number and plus/minus infinity. Other Alpha
+compilers call this option @option{-ieee_with_no_inexact}.
+
+@item -mieee-with-inexact
+@opindex mieee-with-inexact
+This is like @option{-mieee} except the generated code also maintains
+the IEEE @var{inexact-flag}. Turning on this option causes the
+generated code to implement fully-compliant IEEE math. In addition to
+@code{_IEEE_FP}, @code{_IEEE_FP_EXACT} is defined as a preprocessor
+macro. On some Alpha implementations the resulting code may execute
+significantly slower than the code generated by default. Since there is
+very little code that depends on the @var{inexact-flag}, you should
+normally not specify this option. Other Alpha compilers call this
+option @option{-ieee_with_inexact}.
+
+@item -mfp-trap-mode=@var{trap-mode}
+@opindex mfp-trap-mode
+This option controls what floating-point related traps are enabled.
+Other Alpha compilers call this option @option{-fptm @var{trap-mode}}.
+The trap mode can be set to one of four values:
+
+@table @samp
+@item n
+This is the default (normal) setting. The only traps that are enabled
+are the ones that cannot be disabled in software (e.g., division by zero
+trap).
+
+@item u
+In addition to the traps enabled by @samp{n}, underflow traps are enabled
+as well.
+
+@item su
+Like @samp{u}, but the instructions are marked to be safe for software
+completion (see Alpha architecture manual for details).
+
+@item sui
+Like @samp{su}, but inexact traps are enabled as well.
+@end table
+
+@item -mfp-rounding-mode=@var{rounding-mode}
+@opindex mfp-rounding-mode
+Selects the IEEE rounding mode. Other Alpha compilers call this option
+@option{-fprm @var{rounding-mode}}. The @var{rounding-mode} can be one
+of:
+
+@table @samp
+@item n
+Normal IEEE rounding mode. Floating point numbers are rounded towards
+the nearest machine number or towards the even machine number in case
+of a tie.
+
+@item m
+Round towards minus infinity.
+
+@item c
+Chopped rounding mode. Floating point numbers are rounded towards zero.
+
+@item d
+Dynamic rounding mode. A field in the floating point control register
+(@var{fpcr}, see Alpha architecture reference manual) controls the
+rounding mode in effect. The C library initializes this register for
+rounding towards plus infinity. Thus, unless your program modifies the
+@var{fpcr}, @samp{d} corresponds to round towards plus infinity.
+@end table
+
+@item -mtrap-precision=@var{trap-precision}
+@opindex mtrap-precision
+In the Alpha architecture, floating point traps are imprecise. This
+means without software assistance it is impossible to recover from a
+floating trap and program execution normally needs to be terminated.
+GCC can generate code that can assist operating system trap handlers
+in determining the exact location that caused a floating point trap.
+Depending on the requirements of an application, different levels of
+precisions can be selected:
+
+@table @samp
+@item p
+Program precision. This option is the default and means a trap handler
+can only identify which program caused a floating point exception.
+
+@item f
+Function precision. The trap handler can determine the function that
+caused a floating point exception.
+
+@item i
+Instruction precision. The trap handler can determine the exact
+instruction that caused a floating point exception.
+@end table
+
+Other Alpha compilers provide the equivalent options called
+@option{-scope_safe} and @option{-resumption_safe}.
+
+@item -mieee-conformant
+@opindex mieee-conformant
+This option marks the generated code as IEEE conformant. You must not
+use this option unless you also specify @option{-mtrap-precision=i} and either
+@option{-mfp-trap-mode=su} or @option{-mfp-trap-mode=sui}. Its only effect
+is to emit the line @samp{.eflag 48} in the function prologue of the
+generated assembly file. Under DEC Unix, this has the effect that
+IEEE-conformant math library routines will be linked in.
+
+@item -mbuild-constants
+@opindex mbuild-constants
+Normally GCC examines a 32- or 64-bit integer constant to
+see if it can construct it from smaller constants in two or three
+instructions. If it cannot, it will output the constant as a literal and
+generate code to load it from the data segment at runtime.
+
+Use this option to require GCC to construct @emph{all} integer constants
+using code, even if it takes more instructions (the maximum is six).
+
+You would typically use this option to build a shared library dynamic
+loader. Itself a shared library, it must relocate itself in memory
+before it can find the variables and constants in its own data segment.
+
+@item -malpha-as
+@itemx -mgas
+@opindex malpha-as
+@opindex mgas
+Select whether to generate code to be assembled by the vendor-supplied
+assembler (@option{-malpha-as}) or by the GNU assembler @option{-mgas}.
+
+@item -mbwx
+@itemx -mno-bwx
+@itemx -mcix
+@itemx -mno-cix
+@itemx -mfix
+@itemx -mno-fix
+@itemx -mmax
+@itemx -mno-max
+@opindex mbwx
+@opindex mno-bwx
+@opindex mcix
+@opindex mno-cix
+@opindex mfix
+@opindex mno-fix
+@opindex mmax
+@opindex mno-max
+Indicate whether GCC should generate code to use the optional BWX,
+CIX, FIX and MAX instruction sets. The default is to use the instruction
+sets supported by the CPU type specified via @option{-mcpu=} option or that
+of the CPU on which GCC was built if none was specified.
+
+@item -mfloat-vax
+@itemx -mfloat-ieee
+@opindex mfloat-vax
+@opindex mfloat-ieee
+Generate code that uses (does not use) VAX F and G floating point
+arithmetic instead of IEEE single and double precision.
+
+@item -mexplicit-relocs
+@itemx -mno-explicit-relocs
+@opindex mexplicit-relocs
+@opindex mno-explicit-relocs
+Older Alpha assemblers provided no way to generate symbol relocations
+except via assembler macros. Use of these macros does not allow
+optimal instruction scheduling. GNU binutils as of version 2.12
+supports a new syntax that allows the compiler to explicitly mark
+which relocations should apply to which instructions. This option
+is mostly useful for debugging, as GCC detects the capabilities of
+the assembler when it is built and sets the default accordingly.
+
+@item -msmall-data
+@itemx -mlarge-data
+@opindex msmall-data
+@opindex mlarge-data
+When @option{-mexplicit-relocs} is in effect, static data is
+accessed via @dfn{gp-relative} relocations. When @option{-msmall-data}
+is used, objects 8 bytes long or smaller are placed in a @dfn{small data area}
+(the @code{.sdata} and @code{.sbss} sections) and are accessed via
+16-bit relocations off of the @code{$gp} register. This limits the
+size of the small data area to 64KB, but allows the variables to be
+directly accessed via a single instruction.
+
+The default is @option{-mlarge-data}. With this option the data area
+is limited to just below 2GB@. Programs that require more than 2GB of
+data must use @code{malloc} or @code{mmap} to allocate the data in the
+heap instead of in the program's data segment.
+
+When generating code for shared libraries, @option{-fpic} implies
+@option{-msmall-data} and @option{-fPIC} implies @option{-mlarge-data}.
+
+@item -msmall-text
+@itemx -mlarge-text
+@opindex msmall-text
+@opindex mlarge-text
+When @option{-msmall-text} is used, the compiler assumes that the
+code of the entire program (or shared library) fits in 4MB, and is
+thus reachable with a branch instruction. When @option{-msmall-data}
+is used, the compiler can assume that all local symbols share the
+same @code{$gp} value, and thus reduce the number of instructions
+required for a function call from 4 to 1.
+
+The default is @option{-mlarge-text}.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set and instruction scheduling parameters for
+machine type @var{cpu_type}. You can specify either the @samp{EV}
+style name or the corresponding chip number. GCC supports scheduling
+parameters for the EV4, EV5 and EV6 family of processors and will
+choose the default values for the instruction set from the processor
+you specify. If you do not specify a processor type, GCC will default
+to the processor on which the compiler was built.
+
+Supported values for @var{cpu_type} are
+
+@table @samp
+@item ev4
+@itemx ev45
+@itemx 21064
+Schedules as an EV4 and has no instruction set extensions.
+
+@item ev5
+@itemx 21164
+Schedules as an EV5 and has no instruction set extensions.
+
+@item ev56
+@itemx 21164a
+Schedules as an EV5 and supports the BWX extension.
+
+@item pca56
+@itemx 21164pc
+@itemx 21164PC
+Schedules as an EV5 and supports the BWX and MAX extensions.
+
+@item ev6
+@itemx 21264
+Schedules as an EV6 and supports the BWX, FIX, and MAX extensions.
+
+@item ev67
+@itemx 21264a
+Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
+@end table
+
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mcpu=native} has no effect if GCC does not recognize
+the processor.
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set only the instruction scheduling parameters for machine type
+@var{cpu_type}. The instruction set is not changed.
+
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-mtune=native} has no effect if GCC does not recognize
+the processor.
+
+@item -mmemory-latency=@var{time}
+@opindex mmemory-latency
+Sets the latency the scheduler should assume for typical memory
+references as seen by the application. This number is highly
+dependent on the memory access patterns used by the application
+and the size of the external cache on the machine.
+
+Valid options for @var{time} are
+
+@table @samp
+@item @var{number}
+A decimal number representing clock cycles.
+
+@item L1
+@itemx L2
+@itemx L3
+@itemx main
+The compiler contains estimates of the number of clock cycles for
+``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3 caches
+(also called Dcache, Scache, and Bcache), as well as to main memory.
+Note that L3 is only valid for EV5.
+
+@end table
+@end table
+
+@node DEC Alpha/VMS Options
+@subsection DEC Alpha/VMS Options
+
+These @samp{-m} options are defined for the DEC Alpha/VMS implementations:
+
+@table @gcctabopt
+@item -mvms-return-codes
+@opindex mvms-return-codes
+Return VMS condition codes from main. The default is to return POSIX
+style condition (e.g.@: error) codes.
+@end table
+
+@node FR30 Options
+@subsection FR30 Options
+@cindex FR30 Options
+
+These options are defined specifically for the FR30 port.
+
+@table @gcctabopt
+
+@item -msmall-model
+@opindex msmall-model
+Use the small address space model. This can produce smaller code, but
+it does assume that all symbolic values and addresses will fit into a
+20-bit range.
+
+@item -mno-lsim
+@opindex mno-lsim
+Assume that run-time support has been provided and so there is no need
+to include the simulator library (@file{libsim.a}) on the linker
+command line.
+
+@end table
+
+@node FRV Options
+@subsection FRV Options
+@cindex FRV Options
+
+@table @gcctabopt
+@item -mgpr-32
+@opindex mgpr-32
+
+Only use the first 32 general purpose registers.
+
+@item -mgpr-64
+@opindex mgpr-64
+
+Use all 64 general purpose registers.
+
+@item -mfpr-32
+@opindex mfpr-32
+
+Use only the first 32 floating point registers.
+
+@item -mfpr-64
+@opindex mfpr-64
+
+Use all 64 floating point registers
+
+@item -mhard-float
+@opindex mhard-float
+
+Use hardware instructions for floating point operations.
+
+@item -msoft-float
+@opindex msoft-float
+
+Use library routines for floating point operations.
+
+@item -malloc-cc
+@opindex malloc-cc
+
+Dynamically allocate condition code registers.
+
+@item -mfixed-cc
+@opindex mfixed-cc
+
+Do not try to dynamically allocate condition code registers, only
+use @code{icc0} and @code{fcc0}.
+
+@item -mdword
+@opindex mdword
+
+Change ABI to use double word insns.
+
+@item -mno-dword
+@opindex mno-dword
+
+Do not use double word instructions.
+
+@item -mdouble
+@opindex mdouble
+
+Use floating point double instructions.
+
+@item -mno-double
+@opindex mno-double
+
+Do not use floating point double instructions.
+
+@item -mmedia
+@opindex mmedia
+
+Use media instructions.
+
+@item -mno-media
+@opindex mno-media
+
+Do not use media instructions.
+
+@item -mmuladd
+@opindex mmuladd
+
+Use multiply and add/subtract instructions.
+
+@item -mno-muladd
+@opindex mno-muladd
+
+Do not use multiply and add/subtract instructions.
+
+@item -mfdpic
+@opindex mfdpic
+
+Select the FDPIC ABI, that uses function descriptors to represent
+pointers to functions. Without any PIC/PIE-related options, it
+implies @option{-fPIE}. With @option{-fpic} or @option{-fpie}, it
+assumes GOT entries and small data are within a 12-bit range from the
+GOT base address; with @option{-fPIC} or @option{-fPIE}, GOT offsets
+are computed with 32 bits.
+With a @samp{bfin-elf} target, this option implies @option{-msim}.
+
+@item -minline-plt
+@opindex minline-plt
+
+Enable inlining of PLT entries in function calls to functions that are
+not known to bind locally. It has no effect without @option{-mfdpic}.
+It's enabled by default if optimizing for speed and compiling for
+shared libraries (i.e., @option{-fPIC} or @option{-fpic}), or when an
+optimization option such as @option{-O3} or above is present in the
+command line.
+
+@item -mTLS
+@opindex TLS
+
+Assume a large TLS segment when generating thread-local code.
+
+@item -mtls
+@opindex tls
+
+Do not assume a large TLS segment when generating thread-local code.
+
+@item -mgprel-ro
+@opindex mgprel-ro
+
+Enable the use of @code{GPREL} relocations in the FDPIC ABI for data
+that is known to be in read-only sections. It's enabled by default,
+except for @option{-fpic} or @option{-fpie}: even though it may help
+make the global offset table smaller, it trades 1 instruction for 4.
+With @option{-fPIC} or @option{-fPIE}, it trades 3 instructions for 4,
+one of which may be shared by multiple symbols, and it avoids the need
+for a GOT entry for the referenced symbol, so it's more likely to be a
+win. If it is not, @option{-mno-gprel-ro} can be used to disable it.
+
+@item -multilib-library-pic
+@opindex multilib-library-pic
+
+Link with the (library, not FD) pic libraries. It's implied by
+@option{-mlibrary-pic}, as well as by @option{-fPIC} and
+@option{-fpic} without @option{-mfdpic}. You should never have to use
+it explicitly.
+
+@item -mlinked-fp
+@opindex mlinked-fp
+
+Follow the EABI requirement of always creating a frame pointer whenever
+a stack frame is allocated. This option is enabled by default and can
+be disabled with @option{-mno-linked-fp}.
+
+@item -mlong-calls
+@opindex mlong-calls
+
+Use indirect addressing to call functions outside the current
+compilation unit. This allows the functions to be placed anywhere
+within the 32-bit address space.
+
+@item -malign-labels
+@opindex malign-labels
+
+Try to align labels to an 8-byte boundary by inserting nops into the
+previous packet. This option only has an effect when VLIW packing
+is enabled. It doesn't create new packets; it merely adds nops to
+existing ones.
+
+@item -mlibrary-pic
+@opindex mlibrary-pic
+
+Generate position-independent EABI code.
+
+@item -macc-4
+@opindex macc-4
+
+Use only the first four media accumulator registers.
+
+@item -macc-8
+@opindex macc-8
+
+Use all eight media accumulator registers.
+
+@item -mpack
+@opindex mpack
+
+Pack VLIW instructions.
+
+@item -mno-pack
+@opindex mno-pack
+
+Do not pack VLIW instructions.
+
+@item -mno-eflags
+@opindex mno-eflags
+
+Do not mark ABI switches in e_flags.
+
+@item -mcond-move
+@opindex mcond-move
+
+Enable the use of conditional-move instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-cond-move
+@opindex mno-cond-move
+
+Disable the use of conditional-move instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mscc
+@opindex mscc
+
+Enable the use of conditional set instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-scc
+@opindex mno-scc
+
+Disable the use of conditional set instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mcond-exec
+@opindex mcond-exec
+
+Enable the use of conditional execution (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-cond-exec
+@opindex mno-cond-exec
+
+Disable the use of conditional execution.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mvliw-branch
+@opindex mvliw-branch
+
+Run a pass to pack branches into VLIW instructions (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-vliw-branch
+@opindex mno-vliw-branch
+
+Do not run a pass to pack branches into VLIW instructions.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mmulti-cond-exec
+@opindex mmulti-cond-exec
+
+Enable optimization of @code{&&} and @code{||} in conditional execution
+(default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-multi-cond-exec
+@opindex mno-multi-cond-exec
+
+Disable optimization of @code{&&} and @code{||} in conditional execution.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mnested-cond-exec
+@opindex mnested-cond-exec
+
+Enable nested conditional execution optimizations (default).
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -mno-nested-cond-exec
+@opindex mno-nested-cond-exec
+
+Disable nested conditional execution optimizations.
+
+This switch is mainly for debugging the compiler and will likely be removed
+in a future version.
+
+@item -moptimize-membar
+@opindex moptimize-membar
+
+This switch removes redundant @code{membar} instructions from the
+compiler generated code. It is enabled by default.
+
+@item -mno-optimize-membar
+@opindex mno-optimize-membar
+
+This switch disables the automatic removal of redundant @code{membar}
+instructions from the generated code.
+
+@item -mtomcat-stats
+@opindex mtomcat-stats
+
+Cause gas to print out tomcat statistics.
+
+@item -mcpu=@var{cpu}
+@opindex mcpu
+
+Select the processor type for which to generate code. Possible values are
+@samp{frv}, @samp{fr550}, @samp{tomcat}, @samp{fr500}, @samp{fr450},
+@samp{fr405}, @samp{fr400}, @samp{fr300} and @samp{simple}.
+
+@end table
+
+@node GNU/Linux Options
+@subsection GNU/Linux Options
+
+These @samp{-m} options are defined for GNU/Linux targets:
+
+@table @gcctabopt
+@item -mglibc
+@opindex mglibc
+Use the GNU C library instead of uClibc. This is the default except
+on @samp{*-*-linux-*uclibc*} targets.
+
+@item -muclibc
+@opindex muclibc
+Use uClibc instead of the GNU C library. This is the default on
+@samp{*-*-linux-*uclibc*} targets.
+@end table
+
+@node H8/300 Options
+@subsection H8/300 Options
+
+These @samp{-m} options are defined for the H8/300 implementations:
+
+@table @gcctabopt
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}. @xref{H8/300,, @code{ld} and the H8/300,
+ld, Using ld}, for a fuller description.
+
+@item -mh
+@opindex mh
+Generate code for the H8/300H@.
+
+@item -ms
+@opindex ms
+Generate code for the H8S@.
+
+@item -mn
+@opindex mn
+Generate code for the H8S and H8/300H in the normal mode. This switch
+must be used either with @option{-mh} or @option{-ms}.
+
+@item -ms2600
+@opindex ms2600
+Generate code for the H8S/2600. This switch must be used with @option{-ms}.
+
+@item -mint32
+@opindex mint32
+Make @code{int} data 32 bits by default.
+
+@item -malign-300
+@opindex malign-300
+On the H8/300H and H8S, use the same alignment rules as for the H8/300.
+The default for the H8/300H and H8S is to align longs and floats on 4
+byte boundaries.
+@option{-malign-300} causes them to be aligned on 2 byte boundaries.
+This option has no effect on the H8/300.
+@end table
+
+@node HPPA Options
+@subsection HPPA Options
+@cindex HPPA Options
+
+These @samp{-m} options are defined for the HPPA family of computers:
+
+@table @gcctabopt
+@item -march=@var{architecture-type}
+@opindex march
+Generate code for the specified architecture. The choices for
+@var{architecture-type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA
+1.1, and @samp{2.0} for PA 2.0 processors. Refer to
+@file{/usr/lib/sched.models} on an HP-UX system to determine the proper
+architecture option for your machine. Code compiled for lower numbered
+architectures will run on higher numbered architectures, but not the
+other way around.
+
+@item -mpa-risc-1-0
+@itemx -mpa-risc-1-1
+@itemx -mpa-risc-2-0
+@opindex mpa-risc-1-0
+@opindex mpa-risc-1-1
+@opindex mpa-risc-2-0
+Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively.
+
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables. Use this option only if
+the assembler/linker complain about out of range branches within a switch
+table.
+
+@item -mjump-in-delay
+@opindex mjump-in-delay
+Fill delay slots of function calls with unconditional jump instructions
+by modifying the return pointer for the function call to be the target
+of the conditional jump.
+
+@item -mdisable-fpregs
+@opindex mdisable-fpregs
+Prevent floating point registers from being used in any manner. This is
+necessary for compiling kernels which perform lazy context switching of
+floating point registers. If you use this option and attempt to perform
+floating point operations, the compiler will abort.
+
+@item -mdisable-indexing
+@opindex mdisable-indexing
+Prevent the compiler from using indexing address modes. This avoids some
+rather obscure problems when compiling MIG generated code under MACH@.
+
+@item -mno-space-regs
+@opindex mno-space-regs
+Generate code that assumes the target has no space registers. This allows
+GCC to generate faster indirect calls and use unscaled index address modes.
+
+Such code is suitable for level 0 PA systems and kernels.
+
+@item -mfast-indirect-calls
+@opindex mfast-indirect-calls
+Generate code that assumes calls never cross space boundaries. This
+allows GCC to emit code which performs faster indirect calls.
+
+This option will not work in the presence of shared libraries or nested
+functions.
+
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use. This is
+useful when compiling kernel code. A register range is specified as
+two registers separated by a dash. Multiple register ranges can be
+specified separated by a comma.
+
+@item -mlong-load-store
+@opindex mlong-load-store
+Generate 3-instruction load and store sequences as sometimes required by
+the HP-UX 10 linker. This is equivalent to the @samp{+k} option to
+the HP compilers.
+
+@item -mportable-runtime
+@opindex mportable-runtime
+Use the portable calling conventions proposed by HP for ELF systems.
+
+@item -mgas
+@opindex mgas
+Enable the use of assembler directives only GAS understands.
+
+@item -mschedule=@var{cpu-type}
+@opindex mschedule
+Schedule code according to the constraints for the machine type
+@var{cpu-type}. The choices for @var{cpu-type} are @samp{700}
+@samp{7100}, @samp{7100LC}, @samp{7200}, @samp{7300} and @samp{8000}. Refer
+to @file{/usr/lib/sched.models} on an HP-UX system to determine the
+proper scheduling option for your machine. The default scheduling is
+@samp{8000}.
+
+@item -mlinker-opt
+@opindex mlinker-opt
+Enable the optimization pass in the HP-UX linker. Note this makes symbolic
+debugging impossible. It also triggers a bug in the HP-UX 8 and HP-UX 9
+linkers in which they give bogus error messages when linking some programs.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all HPPA
+targets. Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation. You must make
+your own arrangements to provide suitable library functions for
+cross-compilation.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option. In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -msio
+@opindex msio
+Generate the predefine, @code{_SIO}, for server IO@. The default is
+@option{-mwsio}. This generates the predefines, @code{__hp9000s700},
+@code{__hp9000s700__} and @code{_WSIO}, for workstation IO@. These
+options are available under HP-UX and HI-UX@.
+
+@item -mgnu-ld
+@opindex gnu-ld
+Use GNU ld specific options. This passes @option{-shared} to ld when
+building a shared library. It is the default when GCC is configured,
+explicitly or implicitly, with the GNU linker. This option does not
+have any affect on which ld is called, it only changes what parameters
+are passed to that ld. The ld that is called is determined by the
+@option{--with-ld} configure option, GCC's program search path, and
+finally by the user's @env{PATH}. The linker used by GCC can be printed
+using @samp{which `gcc -print-prog-name=ld`}. This option is only available
+on the 64 bit HP-UX GCC, i.e.@: configured with @samp{hppa*64*-*-hpux*}.
+
+@item -mhp-ld
+@opindex hp-ld
+Use HP ld specific options. This passes @option{-b} to ld when building
+a shared library and passes @option{+Accept TypeMismatch} to ld on all
+links. It is the default when GCC is configured, explicitly or
+implicitly, with the HP linker. This option does not have any affect on
+which ld is called, it only changes what parameters are passed to that
+ld. The ld that is called is determined by the @option{--with-ld}
+configure option, GCC's program search path, and finally by the user's
+@env{PATH}. The linker used by GCC can be printed using @samp{which
+`gcc -print-prog-name=ld`}. This option is only available on the 64 bit
+HP-UX GCC, i.e.@: configured with @samp{hppa*64*-*-hpux*}.
+
+@item -mlong-calls
+@opindex mno-long-calls
+Generate code that uses long call sequences. This ensures that a call
+is always able to reach linker generated stubs. The default is to generate
+long calls only when the distance from the call site to the beginning
+of the function or translation unit, as the case may be, exceeds a
+predefined limit set by the branch type being used. The limits for
+normal calls are 7,600,000 and 240,000 bytes, respectively for the
+PA 2.0 and PA 1.X architectures. Sibcalls are always limited at
+240,000 bytes.
+
+Distances are measured from the beginning of functions when using the
+@option{-ffunction-sections} option, or when using the @option{-mgas}
+and @option{-mno-portable-runtime} options together under HP-UX with
+the SOM linker.
+
+It is normally not desirable to use this option as it will degrade
+performance. However, it may be useful in large applications,
+particularly when partial linking is used to build the application.
+
+The types of long calls used depends on the capabilities of the
+assembler and linker, and the type of code being generated. The
+impact on systems that support long absolute calls, and long pic
+symbol-difference or pc-relative calls should be relatively small.
+However, an indirect call is used on 32-bit ELF systems in pic code
+and it is quite long.
+
+@item -munix=@var{unix-std}
+@opindex march
+Generate compiler predefines and select a startfile for the specified
+UNIX standard. The choices for @var{unix-std} are @samp{93}, @samp{95}
+and @samp{98}. @samp{93} is supported on all HP-UX versions. @samp{95}
+is available on HP-UX 10.10 and later. @samp{98} is available on HP-UX
+11.11 and later. The default values are @samp{93} for HP-UX 10.00,
+@samp{95} for HP-UX 10.10 though to 11.00, and @samp{98} for HP-UX 11.11
+and later.
+
+@option{-munix=93} provides the same predefines as GCC 3.3 and 3.4.
+@option{-munix=95} provides additional predefines for @code{XOPEN_UNIX}
+and @code{_XOPEN_SOURCE_EXTENDED}, and the startfile @file{unix95.o}.
+@option{-munix=98} provides additional predefines for @code{_XOPEN_UNIX},
+@code{_XOPEN_SOURCE_EXTENDED}, @code{_INCLUDE__STDC_A1_SOURCE} and
+@code{_INCLUDE_XOPEN_SOURCE_500}, and the startfile @file{unix98.o}.
+
+It is @emph{important} to note that this option changes the interfaces
+for various library routines. It also affects the operational behavior
+of the C library. Thus, @emph{extreme} care is needed in using this
+option.
+
+Library code that is intended to operate with more than one UNIX
+standard must test, set and restore the variable @var{__xpg4_extended_mask}
+as appropriate. Most GNU software doesn't provide this capability.
+
+@item -nolibdld
+@opindex nolibdld
+Suppress the generation of link options to search libdld.sl when the
+@option{-static} option is specified on HP-UX 10 and later.
+
+@item -static
+@opindex static
+The HP-UX implementation of setlocale in libc has a dependency on
+libdld.sl. There isn't an archive version of libdld.sl. Thus,
+when the @option{-static} option is specified, special link options
+are needed to resolve this dependency.
+
+On HP-UX 10 and later, the GCC driver adds the necessary options to
+link with libdld.sl when the @option{-static} option is specified.
+This causes the resulting binary to be dynamic. On the 64-bit port,
+the linkers generate dynamic binaries by default in any case. The
+@option{-nolibdld} option can be used to prevent the GCC driver from
+adding these link options.
+
+@item -threads
+@opindex threads
+Add support for multithreading with the @dfn{dce thread} library
+under HP-UX@. This option sets flags for both the preprocessor and
+linker.
+@end table
+
+@node i386 and x86-64 Options
+@subsection Intel 386 and AMD x86-64 Options
+@cindex i386 Options
+@cindex x86-64 Options
+@cindex Intel 386 Options
+@cindex AMD x86-64 Options
+
+These @samp{-m} options are defined for the i386 and x86-64 family of
+computers:
+
+@table @gcctabopt
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Tune to @var{cpu-type} everything applicable about the generated code, except
+for the ABI and the set of available instructions. The choices for
+@var{cpu-type} are:
+@table @emph
+@item generic
+Produce code optimized for the most common IA32/AMD64/EM64T processors.
+If you know the CPU on which your code will run, then you should use
+the corresponding @option{-mtune} option instead of
+@option{-mtune=generic}. But, if you do not know exactly what CPU users
+of your application will have, then you should use this option.
+
+As new processors are deployed in the marketplace, the behavior of this
+option will change. Therefore, if you upgrade to a newer version of
+GCC, the code generated option will change to reflect the processors
+that were most common when that version of GCC was released.
+
+There is no @option{-march=generic} option because @option{-march}
+indicates the instruction set the compiler can use, and there is no
+generic instruction set applicable to all processors. In contrast,
+@option{-mtune} indicates the processor (or, in this case, collection of
+processors) for which the code is optimized.
+@item native
+This selects the CPU to tune for at compilation time by determining
+the processor type of the compiling machine. Using @option{-mtune=native}
+will produce code optimized for the local machine under the constraints
+of the selected instruction set. Using @option{-march=native} will
+enable all instruction subsets supported by the local machine (hence
+the result might not run on different machines).
+@item i386
+Original Intel's i386 CPU@.
+@item i486
+Intel's i486 CPU@. (No scheduling is implemented for this chip.)
+@item i586, pentium
+Intel Pentium CPU with no MMX support.
+@item pentium-mmx
+Intel PentiumMMX CPU based on Pentium core with MMX instruction set support.
+@item pentiumpro
+Intel PentiumPro CPU@.
+@item i686
+Same as @code{generic}, but when used as @code{march} option, PentiumPro
+instruction set will be used, so the code will run on all i686 family chips.
+@item pentium2
+Intel Pentium2 CPU based on PentiumPro core with MMX instruction set support.
+@item pentium3, pentium3m
+Intel Pentium3 CPU based on PentiumPro core with MMX and SSE instruction set
+support.
+@item pentium-m
+Low power version of Intel Pentium3 CPU with MMX, SSE and SSE2 instruction set
+support. Used by Centrino notebooks.
+@item pentium4, pentium4m
+Intel Pentium4 CPU with MMX, SSE and SSE2 instruction set support.
+@item prescott
+Improved version of Intel Pentium4 CPU with MMX, SSE, SSE2 and SSE3 instruction
+set support.
+@item nocona
+Improved version of Intel Pentium4 CPU with 64-bit extensions, MMX, SSE,
+SSE2 and SSE3 instruction set support.
+@item core2
+Intel Core2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3
+instruction set support.
+@item k6
+AMD K6 CPU with MMX instruction set support.
+@item k6-2, k6-3
+Improved versions of AMD K6 CPU with MMX and 3dNOW!@: instruction set support.
+@item athlon, athlon-tbird
+AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW!@: and SSE prefetch instructions
+support.
+@item athlon-4, athlon-xp, athlon-mp
+Improved AMD Athlon CPU with MMX, 3dNOW!, enhanced 3dNOW!@: and full SSE
+instruction set support.
+@item k8, opteron, athlon64, athlon-fx
+AMD K8 core based CPUs with x86-64 instruction set support. (This supersets
+MMX, SSE, SSE2, 3dNOW!, enhanced 3dNOW!@: and 64-bit instruction set extensions.)
+@item k8-sse3, opteron-sse3, athlon64-sse3
+Improved versions of k8, opteron and athlon64 with SSE3 instruction set support.
+@item amdfam10, barcelona
+AMD Family 10h core based CPUs with x86-64 instruction set support. (This
+supersets MMX, SSE, SSE2, SSE3, SSE4A, 3dNOW!, enhanced 3dNOW!, ABM and 64-bit
+instruction set extensions.)
+@item winchip-c6
+IDT Winchip C6 CPU, dealt in same way as i486 with additional MMX instruction
+set support.
+@item winchip2
+IDT Winchip2 CPU, dealt in same way as i486 with additional MMX and 3dNOW!@:
+instruction set support.
+@item c3
+Via C3 CPU with MMX and 3dNOW!@: instruction set support. (No scheduling is
+implemented for this chip.)
+@item c3-2
+Via C3-2 CPU with MMX and SSE instruction set support. (No scheduling is
+implemented for this chip.)
+@item geode
+Embedded AMD CPU with MMX and 3dNOW! instruction set support.
+@end table
+
+While picking a specific @var{cpu-type} will schedule things appropriately
+for that particular chip, the compiler will not generate any code that
+does not run on the i386 without the @option{-march=@var{cpu-type}} option
+being used.
+
+@item -march=@var{cpu-type}
+@opindex march
+Generate instructions for the machine type @var{cpu-type}. The choices
+for @var{cpu-type} are the same as for @option{-mtune}. Moreover,
+specifying @option{-march=@var{cpu-type}} implies @option{-mtune=@var{cpu-type}}.
+
+@item -mcpu=@var{cpu-type}
+@opindex mcpu
+A deprecated synonym for @option{-mtune}.
+
+@item -mfpmath=@var{unit}
+@opindex march
+Generate floating point arithmetics for selected unit @var{unit}. The choices
+for @var{unit} are:
+
+@table @samp
+@item 387
+Use the standard 387 floating point coprocessor present majority of chips and
+emulated otherwise. Code compiled with this option will run almost everywhere.
+The temporary results are computed in 80bit precision instead of precision
+specified by the type resulting in slightly different results compared to most
+of other chips. See @option{-ffloat-store} for more detailed description.
+
+This is the default choice for i386 compiler.
+
+@item sse
+Use scalar floating point instructions present in the SSE instruction set.
+This instruction set is supported by Pentium3 and newer chips, in the AMD line
+by Athlon-4, Athlon-xp and Athlon-mp chips. The earlier version of SSE
+instruction set supports only single precision arithmetics, thus the double and
+extended precision arithmetics is still done using 387. Later version, present
+only in Pentium4 and the future AMD x86-64 chips supports double precision
+arithmetics too.
+
+For the i386 compiler, you need to use @option{-march=@var{cpu-type}}, @option{-msse}
+or @option{-msse2} switches to enable SSE extensions and make this option
+effective. For the x86-64 compiler, these extensions are enabled by default.
+
+The resulting code should be considerably faster in the majority of cases and avoid
+the numerical instability problems of 387 code, but may break some existing
+code that expects temporaries to be 80bit.
+
+This is the default choice for the x86-64 compiler.
+
+@item sse,387
+@itemx sse+387
+@itemx both
+Attempt to utilize both instruction sets at once. This effectively double the
+amount of available registers and on chips with separate execution units for
+387 and SSE the execution resources too. Use this option with care, as it is
+still experimental, because the GCC register allocator does not model separate
+functional units well resulting in instable performance.
+@end table
+
+@item -masm=@var{dialect}
+@opindex masm=@var{dialect}
+Output asm instructions using selected @var{dialect}. Supported
+choices are @samp{intel} or @samp{att} (the default one). Darwin does
+not support @samp{intel}.
+
+@item -mieee-fp
+@itemx -mno-ieee-fp
+@opindex mieee-fp
+@opindex mno-ieee-fp
+Control whether or not the compiler uses IEEE floating point
+comparisons. These handle correctly the case where the result of a
+comparison is unordered.
+
+@item -msoft-float
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not part of GCC@.
+Normally the facilities of the machine's usual C compiler are used, but
+this can't be done directly in cross-compilation. You must make your
+own arrangements to provide suitable library functions for
+cross-compilation.
+
+On machines where a function returns floating point results in the 80387
+register stack, some floating point opcodes may be emitted even if
+@option{-msoft-float} is used.
+
+@item -mno-fp-ret-in-387
+@opindex mno-fp-ret-in-387
+Do not use the FPU registers for return values of functions.
+
+The usual calling convention has functions return values of types
+@code{float} and @code{double} in an FPU register, even if there
+is no FPU@. The idea is that the operating system should emulate
+an FPU@.
+
+The option @option{-mno-fp-ret-in-387} causes such values to be returned
+in ordinary CPU registers instead.
+
+@item -mno-fancy-math-387
+@opindex mno-fancy-math-387
+Some 387 emulators do not support the @code{sin}, @code{cos} and
+@code{sqrt} instructions for the 387. Specify this option to avoid
+generating those instructions. This option is the default on FreeBSD,
+OpenBSD and NetBSD@. This option is overridden when @option{-march}
+indicates that the target cpu will always have an FPU and so the
+instruction will not need emulation. As of revision 2.6.1, these
+instructions are not generated unless you also use the
+@option{-funsafe-math-optimizations} switch.
+
+@item -malign-double
+@itemx -mno-align-double
+@opindex malign-double
+@opindex mno-align-double
+Control whether GCC aligns @code{double}, @code{long double}, and
+@code{long long} variables on a two word boundary or a one word
+boundary. Aligning @code{double} variables on a two word boundary will
+produce code that runs somewhat faster on a @samp{Pentium} at the
+expense of more memory.
+
+On x86-64, @option{-malign-double} is enabled by default.
+
+@strong{Warning:} if you use the @option{-malign-double} switch,
+structures containing the above types will be aligned differently than
+the published application binary interface specifications for the 386
+and will not be binary compatible with structures in code compiled
+without that switch.
+
+@item -m96bit-long-double
+@itemx -m128bit-long-double
+@opindex m96bit-long-double
+@opindex m128bit-long-double
+These switches control the size of @code{long double} type. The i386
+application binary interface specifies the size to be 96 bits,
+so @option{-m96bit-long-double} is the default in 32 bit mode.
+
+Modern architectures (Pentium and newer) would prefer @code{long double}
+to be aligned to an 8 or 16 byte boundary. In arrays or structures
+conforming to the ABI, this would not be possible. So specifying a
+@option{-m128bit-long-double} will align @code{long double}
+to a 16 byte boundary by padding the @code{long double} with an additional
+32 bit zero.
+
+In the x86-64 compiler, @option{-m128bit-long-double} is the default choice as
+its ABI specifies that @code{long double} is to be aligned on 16 byte boundary.
+
+Notice that neither of these options enable any extra precision over the x87
+standard of 80 bits for a @code{long double}.
+
+@strong{Warning:} if you override the default value for your target ABI, the
+structures and arrays containing @code{long double} variables will change
+their size as well as function calling convention for function taking
+@code{long double} will be modified. Hence they will not be binary
+compatible with arrays or structures in code compiled without that switch.
+
+@item -mlarge-data-threshold=@var{number}
+@opindex mlarge-data-threshold=@var{number}
+When @option{-mcmodel=medium} is specified, the data greater than
+@var{threshold} are placed in large data section. This value must be the
+same across all object linked into the binary and defaults to 65535.
+
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions that
+take a fixed number of arguments return with the @code{ret} @var{num}
+instruction, which pops their arguments while returning. This saves one
+instruction in the caller since there is no need to pop the arguments
+there.
+
+You can specify that an individual function is called with this calling
+sequence with the function attribute @samp{stdcall}. You can also
+override the @option{-mrtd} option by using the function attribute
+@samp{cdecl}. @xref{Function Attributes}.
+
+@strong{Warning:} this calling convention is incompatible with the one
+normally used on Unix, so you cannot use it if you need to call
+libraries compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code will be generated for calls to those
+functions.
+
+In addition, seriously incorrect code will result if you call a
+function with too many arguments. (Normally, extra arguments are
+harmlessly ignored.)
+
+@item -mregparm=@var{num}
+@opindex mregparm
+Control how many registers are used to pass integer arguments. By
+default, no registers are used to pass arguments, and at most 3
+registers can be used. You can control this behavior for a specific
+function by using the function attribute @samp{regparm}.
+@xref{Function Attributes}.
+
+@strong{Warning:} if you use this switch, and
+@var{num} is nonzero, then you must build all modules with the same
+value, including any libraries. This includes the system libraries and
+startup modules.
+
+@item -msseregparm
+@opindex msseregparm
+Use SSE register passing conventions for float and double arguments
+and return values. You can control this behavior for a specific
+function by using the function attribute @samp{sseregparm}.
+@xref{Function Attributes}.
+
+@strong{Warning:} if you use this switch then you must build all
+modules with the same value, including any libraries. This includes
+the system libraries and startup modules.
+
+@item -mpc32
+@itemx -mpc64
+@itemx -mpc80
+@opindex mpc32
+@opindex mpc64
+@opindex mpc80
+
+Set 80387 floating-point precision to 32, 64 or 80 bits. When @option{-mpc32}
+is specified, the significands of results of floating-point operations are
+rounded to 24 bits (single precision); @option{-mpc64} rounds the
+significands of results of floating-point operations to 53 bits (double
+precision) and @option{-mpc80} rounds the significands of results of
+floating-point operations to 64 bits (extended double precision), which is
+the default. When this option is used, floating-point operations in higher
+precisions are not available to the programmer without setting the FPU
+control word explicitly.
+
+Setting the rounding of floating-point operations to less than the default
+80 bits can speed some programs by 2% or more. Note that some mathematical
+libraries assume that extended precision (80 bit) floating-point operations
+are enabled by default; routines in such libraries could suffer significant
+loss of accuracy, typically through so-called "catastrophic cancellation",
+when this option is used to set the precision to less than extended precision.
+
+@item -mstackrealign
+@opindex mstackrealign
+Realign the stack at entry. On the Intel x86, the @option{-mstackrealign}
+option will generate an alternate prologue and epilogue that realigns the
+runtime stack if necessary. This supports mixing legacy codes that keep
+a 4-byte aligned stack with modern codes that keep a 16-byte stack for
+SSE compatibility. See also the attribute @code{force_align_arg_pointer},
+applicable to individual functions.
+
+@item -mpreferred-stack-boundary=@var{num}
+@opindex mpreferred-stack-boundary
+Attempt to keep the stack boundary aligned to a 2 raised to @var{num}
+byte boundary. If @option{-mpreferred-stack-boundary} is not specified,
+the default is 4 (16 bytes or 128 bits).
+
+@item -mincoming-stack-boundary=@var{num}
+@opindex mincoming-stack-boundary
+Assume the incoming stack is aligned to a 2 raised to @var{num} byte
+boundary. If @option{-mincoming-stack-boundary} is not specified,
+the one specified by @option{-mpreferred-stack-boundary} will be used.
+
+On Pentium and PentiumPro, @code{double} and @code{long double} values
+should be aligned to an 8 byte boundary (see @option{-malign-double}) or
+suffer significant run time performance penalties. On Pentium III, the
+Streaming SIMD Extension (SSE) data type @code{__m128} may not work
+properly if it is not 16 byte aligned.
+
+To ensure proper alignment of this values on the stack, the stack boundary
+must be as aligned as that required by any value stored on the stack.
+Further, every function must be generated such that it keeps the stack
+aligned. Thus calling a function compiled with a higher preferred
+stack boundary from a function compiled with a lower preferred stack
+boundary will most likely misalign the stack. It is recommended that
+libraries that use callbacks always use the default setting.
+
+This extra alignment does consume extra stack space, and generally
+increases code size. Code that is sensitive to stack space usage, such
+as embedded systems and operating system kernels, may want to reduce the
+preferred alignment to @option{-mpreferred-stack-boundary=2}.
+
+@item -mmmx
+@itemx -mno-mmx
+@itemx -msse
+@itemx -mno-sse
+@itemx -msse2
+@itemx -mno-sse2
+@itemx -msse3
+@itemx -mno-sse3
+@itemx -mssse3
+@itemx -mno-ssse3
+@itemx -msse4.1
+@itemx -mno-sse4.1
+@itemx -msse4.2
+@itemx -mno-sse4.2
+@itemx -msse4
+@itemx -mno-sse4
+@itemx -mavx
+@itemx -mno-avx
+@itemx -maes
+@itemx -mno-aes
+@itemx -mpclmul
+@itemx -mno-pclmul
+@itemx -msse4a
+@itemx -mno-sse4a
+@itemx -msse5
+@itemx -mno-sse5
+@itemx -m3dnow
+@itemx -mno-3dnow
+@itemx -mpopcnt
+@itemx -mno-popcnt
+@itemx -mabm
+@itemx -mno-abm
+@opindex mmmx
+@opindex mno-mmx
+@opindex msse
+@opindex mno-sse
+@opindex m3dnow
+@opindex mno-3dnow
+These switches enable or disable the use of instructions in the MMX,
+SSE, SSE2, SSE3, SSSE3, SSE4.1, AVX, AES, PCLMUL, SSE4A, SSE5, ABM or
+3DNow!@: extended instruction sets.
+These extensions are also available as built-in functions: see
+@ref{X86 Built-in Functions}, for details of the functions enabled and
+disabled by these switches.
+
+To have SSE/SSE2 instructions generated automatically from floating-point
+code (as opposed to 387 instructions), see @option{-mfpmath=sse}.
+
+GCC depresses SSEx instructions when @option{-mavx} is used. Instead, it
+generates new AVX instructions or AVX equivalence for all SSEx instructions
+when needed.
+
+These options will enable GCC to use these extended instructions in
+generated code, even without @option{-mfpmath=sse}. Applications which
+perform runtime CPU detection must compile separate files for each
+supported architecture, using the appropriate flags. In particular,
+the file containing the CPU detection code should be compiled without
+these options.
+
+@item -mcld
+@opindex mcld
+This option instructs GCC to emit a @code{cld} instruction in the prologue
+of functions that use string instructions. String instructions depend on
+the DF flag to select between autoincrement or autodecrement mode. While the
+ABI specifies the DF flag to be cleared on function entry, some operating
+systems violate this specification by not clearing the DF flag in their
+exception dispatchers. The exception handler can be invoked with the DF flag
+set which leads to wrong direction mode, when string instructions are used.
+This option can be enabled by default on 32-bit x86 targets by configuring
+GCC with the @option{--enable-cld} configure option. Generation of @code{cld}
+instructions can be suppressed with the @option{-mno-cld} compiler option
+in this case.
+
+@item -mcx16
+@opindex mcx16
+This option will enable GCC to use CMPXCHG16B instruction in generated code.
+CMPXCHG16B allows for atomic operations on 128-bit double quadword (or oword)
+data types. This is useful for high resolution counters that could be updated
+by multiple processors (or cores). This instruction is generated as part of
+atomic built-in functions: see @ref{Atomic Builtins} for details.
+
+@item -msahf
+@opindex msahf
+This option will enable GCC to use SAHF instruction in generated 64-bit code.
+Early Intel CPUs with Intel 64 lacked LAHF and SAHF instructions supported
+by AMD64 until introduction of Pentium 4 G1 step in December 2005. LAHF and
+SAHF are load and store instructions, respectively, for certain status flags.
+In 64-bit mode, SAHF instruction is used to optimize @code{fmod}, @code{drem}
+or @code{remainder} built-in functions: see @ref{Other Builtins} for details.
+
+@item -mrecip
+@opindex mrecip
+This option will enable GCC to use RCPSS and RSQRTSS instructions (and their
+vectorized variants RCPPS and RSQRTPS) with an additional Newton-Raphson step
+to increase precision instead of DIVSS and SQRTSS (and their vectorized
+variants) for single precision floating point arguments. These instructions
+are generated only when @option{-funsafe-math-optimizations} is enabled
+together with @option{-finite-math-only} and @option{-fno-trapping-math}.
+Note that while the throughput of the sequence is higher than the throughput
+of the non-reciprocal instruction, the precision of the sequence can be
+decreased by up to 2 ulp (i.e. the inverse of 1.0 equals 0.99999994).
+
+@item -mveclibabi=@var{type}
+@opindex mveclibabi
+Specifies the ABI type to use for vectorizing intrinsics using an
+external library. Supported types are @code{svml} for the Intel short
+vector math library and @code{acml} for the AMD math core library style
+of interfacing. GCC will currently emit calls to @code{vmldExp2},
+@code{vmldLn2}, @code{vmldLog102}, @code{vmldLog102}, @code{vmldPow2},
+@code{vmldTanh2}, @code{vmldTan2}, @code{vmldAtan2}, @code{vmldAtanh2},
+@code{vmldCbrt2}, @code{vmldSinh2}, @code{vmldSin2}, @code{vmldAsinh2},
+@code{vmldAsin2}, @code{vmldCosh2}, @code{vmldCos2}, @code{vmldAcosh2},
+@code{vmldAcos2}, @code{vmlsExp4}, @code{vmlsLn4}, @code{vmlsLog104},
+@code{vmlsLog104}, @code{vmlsPow4}, @code{vmlsTanh4}, @code{vmlsTan4},
+@code{vmlsAtan4}, @code{vmlsAtanh4}, @code{vmlsCbrt4}, @code{vmlsSinh4},
+@code{vmlsSin4}, @code{vmlsAsinh4}, @code{vmlsAsin4}, @code{vmlsCosh4},
+@code{vmlsCos4}, @code{vmlsAcosh4} and @code{vmlsAcos4} for corresponding
+function type when @option{-mveclibabi=svml} is used and @code{__vrd2_sin},
+@code{__vrd2_cos}, @code{__vrd2_exp}, @code{__vrd2_log}, @code{__vrd2_log2},
+@code{__vrd2_log10}, @code{__vrs4_sinf}, @code{__vrs4_cosf},
+@code{__vrs4_expf}, @code{__vrs4_logf}, @code{__vrs4_log2f},
+@code{__vrs4_log10f} and @code{__vrs4_powf} for corresponding function type
+when @option{-mveclibabi=acml} is used. Both @option{-ftree-vectorize} and
+@option{-funsafe-math-optimizations} have to be enabled. A SVML or ACML ABI
+compatible library will have to be specified at link time.
+
+@item -mpush-args
+@itemx -mno-push-args
+@opindex mpush-args
+@opindex mno-push-args
+Use PUSH operations to store outgoing parameters. This method is shorter
+and usually equally fast as method using SUB/MOV operations and is enabled
+by default. In some cases disabling it may improve performance because of
+improved scheduling and reduced dependencies.
+
+@item -maccumulate-outgoing-args
+@opindex maccumulate-outgoing-args
+If enabled, the maximum amount of space required for outgoing arguments will be
+computed in the function prologue. This is faster on most modern CPUs
+because of reduced dependencies, improved scheduling and reduced stack usage
+when preferred stack boundary is not equal to 2. The drawback is a notable
+increase in code size. This switch implies @option{-mno-push-args}.
+
+@item -mthreads
+@opindex mthreads
+Support thread-safe exception handling on @samp{Mingw32}. Code that relies
+on thread-safe exception handling must compile and link all code with the
+@option{-mthreads} option. When compiling, @option{-mthreads} defines
+@option{-D_MT}; when linking, it links in a special thread helper library
+@option{-lmingwthrd} which cleans up per thread exception handling data.
+
+@item -mno-align-stringops
+@opindex mno-align-stringops
+Do not align destination of inlined string operations. This switch reduces
+code size and improves performance in case the destination is already aligned,
+but GCC doesn't know about it.
+
+@item -minline-all-stringops
+@opindex minline-all-stringops
+By default GCC inlines string operations only when destination is known to be
+aligned at least to 4 byte boundary. This enables more inlining, increase code
+size, but may improve performance of code that depends on fast memcpy, strlen
+and memset for short lengths.
+
+@item -minline-stringops-dynamically
+@opindex minline-stringops-dynamically
+For string operation of unknown size, inline runtime checks so for small
+blocks inline code is used, while for large blocks library call is used.
+
+@item -mstringop-strategy=@var{alg}
+@opindex mstringop-strategy=@var{alg}
+Overwrite internal decision heuristic about particular algorithm to inline
+string operation with. The allowed values are @code{rep_byte},
+@code{rep_4byte}, @code{rep_8byte} for expanding using i386 @code{rep} prefix
+of specified size, @code{byte_loop}, @code{loop}, @code{unrolled_loop} for
+expanding inline loop, @code{libcall} for always expanding library call.
+
+@item -momit-leaf-frame-pointer
+@opindex momit-leaf-frame-pointer
+Don't keep the frame pointer in a register for leaf functions. This
+avoids the instructions to save, set up and restore frame pointers and
+makes an extra register available in leaf functions. The option
+@option{-fomit-frame-pointer} removes the frame pointer for all functions
+which might make debugging harder.
+
+@item -mtls-direct-seg-refs
+@itemx -mno-tls-direct-seg-refs
+@opindex mtls-direct-seg-refs
+Controls whether TLS variables may be accessed with offsets from the
+TLS segment register (@code{%gs} for 32-bit, @code{%fs} for 64-bit),
+or whether the thread base pointer must be added. Whether or not this
+is legal depends on the operating system, and whether it maps the
+segment to cover the entire TLS area.
+
+For systems that use GNU libc, the default is on.
+
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+Enable automatic generation of fused floating point multiply-add instructions
+if the ISA supports such instructions. The -mfused-madd option is on by
+default. The fused multiply-add instructions have a different
+rounding behavior compared to executing a multiply followed by an add.
+
+@item -msse2avx
+@itemx -mno-sse2avx
+@opindex msse2avx
+Specify that the assembler should encode SSE instructions with VEX
+prefix. The option @option{-mavx} turns this on by default.
+@end table
+
+These @samp{-m} switches are supported in addition to the above
+on AMD x86-64 processors in 64-bit environments.
+
+@table @gcctabopt
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits and
+generates code that runs on any i386 system.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits and generates code for AMD's x86-64 architecture. For
+darwin only the -m64 option turns off the @option{-fno-pic} and
+@option{-mdynamic-no-pic} options.
+
+@item -mno-red-zone
+@opindex no-red-zone
+Do not use a so called red zone for x86-64 code. The red zone is mandated
+by the x86-64 ABI, it is a 128-byte area beyond the location of the
+stack pointer that will not be modified by signal or interrupt handlers
+and therefore can be used for temporary data without adjusting the stack
+pointer. The flag @option{-mno-red-zone} disables this red zone.
+
+@item -mcmodel=small
+@opindex mcmodel=small
+Generate code for the small code model: the program and its symbols must
+be linked in the lower 2 GB of the address space. Pointers are 64 bits.
+Programs can be statically or dynamically linked. This is the default
+code model.
+
+@item -mcmodel=kernel
+@opindex mcmodel=kernel
+Generate code for the kernel code model. The kernel runs in the
+negative 2 GB of the address space.
+This model has to be used for Linux kernel code.
+
+@item -mcmodel=medium
+@opindex mcmodel=medium
+Generate code for the medium model: The program is linked in the lower 2
+GB of the address space. Small symbols are also placed there. Symbols
+with sizes larger than @option{-mlarge-data-threshold} are put into
+large data or bss sections and can be located above 2GB. Programs can
+be statically or dynamically linked.
+
+@item -mcmodel=large
+@opindex mcmodel=large
+Generate code for the large model: This model makes no assumptions
+about addresses and sizes of sections.
+@end table
+
+@node IA-64 Options
+@subsection IA-64 Options
+@cindex IA-64 Options
+
+These are the @samp{-m} options defined for the Intel IA-64 architecture.
+
+@table @gcctabopt
+@item -mbig-endian
+@opindex mbig-endian
+Generate code for a big endian target. This is the default for HP-UX@.
+
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a little endian target. This is the default for AIX5
+and GNU/Linux.
+
+@item -mgnu-as
+@itemx -mno-gnu-as
+@opindex mgnu-as
+@opindex mno-gnu-as
+Generate (or don't) code for the GNU assembler. This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-as}
+@c is used.
+
+@item -mgnu-ld
+@itemx -mno-gnu-ld
+@opindex mgnu-ld
+@opindex mno-gnu-ld
+Generate (or don't) code for the GNU linker. This is the default.
+@c Also, this is the default if the configure option @option{--with-gnu-ld}
+@c is used.
+
+@item -mno-pic
+@opindex mno-pic
+Generate code that does not use a global pointer register. The result
+is not position independent code, and violates the IA-64 ABI@.
+
+@item -mvolatile-asm-stop
+@itemx -mno-volatile-asm-stop
+@opindex mvolatile-asm-stop
+@opindex mno-volatile-asm-stop
+Generate (or don't) a stop bit immediately before and after volatile asm
+statements.
+
+@item -mregister-names
+@itemx -mno-register-names
+@opindex mregister-names
+@opindex mno-register-names
+Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for
+the stacked registers. This may make assembler output more readable.
+
+@item -mno-sdata
+@itemx -msdata
+@opindex mno-sdata
+@opindex msdata
+Disable (or enable) optimizations that use the small data section. This may
+be useful for working around optimizer bugs.
+
+@item -mconstant-gp
+@opindex mconstant-gp
+Generate code that uses a single constant global pointer value. This is
+useful when compiling kernel code.
-If you specify both @option{-mno-power} and @option{-mno-powerpc}, GCC
-will use only the instructions in the common subset of both
-architectures plus some special AIX common-mode calls, and will not use
-the MQ register. Specifying both @option{-mpower} and @option{-mpowerpc}
-permits GCC to use any instruction from either architecture and to
-allow use of the MQ register; specify this for the Motorola MPC601.
+@item -mauto-pic
+@opindex mauto-pic
+Generate code that is self-relocatable. This implies @option{-mconstant-gp}.
+This is useful when compiling firmware code.
-@item -mnew-mnemonics
-@itemx -mold-mnemonics
-@opindex mnew-mnemonics
-@opindex mold-mnemonics
-Select which mnemonics to use in the generated assembler code. With
-@option{-mnew-mnemonics}, GCC uses the assembler mnemonics defined for
-the PowerPC architecture. With @option{-mold-mnemonics} it uses the
-assembler mnemonics defined for the POWER architecture. Instructions
-defined in only one architecture have only one mnemonic; GCC uses that
-mnemonic irrespective of which of these options is specified.
+@item -minline-float-divide-min-latency
+@opindex minline-float-divide-min-latency
+Generate code for inline divides of floating point values
+using the minimum latency algorithm.
-GCC defaults to the mnemonics appropriate for the architecture in
-use. Specifying @option{-mcpu=@var{cpu_type}} sometimes overrides the
-value of these option. Unless you are building a cross-compiler, you
-should normally not specify either @option{-mnew-mnemonics} or
-@option{-mold-mnemonics}, but should instead accept the default.
+@item -minline-float-divide-max-throughput
+@opindex minline-float-divide-max-throughput
+Generate code for inline divides of floating point values
+using the maximum throughput algorithm.
-@item -mcpu=@var{cpu_type}
-@opindex mcpu
-Set architecture type, register usage, choice of mnemonics, and
-instruction scheduling parameters for machine type @var{cpu_type}.
-Supported values for @var{cpu_type} are @samp{rios}, @samp{rios1},
-@samp{rsc}, @samp{rios2}, @samp{rs64a}, @samp{601}, @samp{602},
-@samp{603}, @samp{603e}, @samp{604}, @samp{604e}, @samp{620},
-@samp{630}, @samp{740}, @samp{7400}, @samp{7450}, @samp{750},
-@samp{power}, @samp{power2}, @samp{powerpc}, @samp{403}, @samp{505},
-@samp{801}, @samp{821}, @samp{823}, and @samp{860} and @samp{common}.
+@item -minline-int-divide-min-latency
+@opindex minline-int-divide-min-latency
+Generate code for inline divides of integer values
+using the minimum latency algorithm.
-@option{-mcpu=common} selects a completely generic processor. Code
-generated under this option will run on any POWER or PowerPC processor.
-GCC will use only the instructions in the common subset of both
-architectures, and will not use the MQ register. GCC assumes a generic
-processor model for scheduling purposes.
+@item -minline-int-divide-max-throughput
+@opindex minline-int-divide-max-throughput
+Generate code for inline divides of integer values
+using the maximum throughput algorithm.
-@option{-mcpu=power}, @option{-mcpu=power2}, @option{-mcpu=powerpc}, and
-@option{-mcpu=powerpc64} specify generic POWER, POWER2, pure 32-bit
-PowerPC (i.e., not MPC601), and 64-bit PowerPC architecture machine
-types, with an appropriate, generic processor model assumed for
-scheduling purposes.
+@item -minline-sqrt-min-latency
+@opindex minline-sqrt-min-latency
+Generate code for inline square roots
+using the minimum latency algorithm.
-The other options specify a specific processor. Code generated under
-those options will run best on that processor, and may not run at all on
-others.
+@item -minline-sqrt-max-throughput
+@opindex minline-sqrt-max-throughput
+Generate code for inline square roots
+using the maximum throughput algorithm.
+
+@item -mno-dwarf2-asm
+@itemx -mdwarf2-asm
+@opindex mno-dwarf2-asm
+@opindex mdwarf2-asm
+Don't (or do) generate assembler code for the DWARF2 line number debugging
+info. This may be useful when not using the GNU assembler.
-The @option{-mcpu} options automatically enable or disable other
-@option{-m} options as follows:
+@item -mearly-stop-bits
+@itemx -mno-early-stop-bits
+@opindex mearly-stop-bits
+@opindex mno-early-stop-bits
+Allow stop bits to be placed earlier than immediately preceding the
+instruction that triggered the stop bit. This can improve instruction
+scheduling, but does not always do so.
-@table @samp
-@item common
-@option{-mno-power}, @option{-mno-powerc}
-
-@item power
-@itemx power2
-@itemx rios1
-@itemx rios2
-@itemx rsc
-@option{-mpower}, @option{-mno-powerpc}, @option{-mno-new-mnemonics}
-
-@item powerpc
-@itemx rs64a
-@itemx 602
-@itemx 603
-@itemx 603e
-@itemx 604
-@itemx 620
-@itemx 630
-@itemx 740
-@itemx 7400
-@itemx 7450
-@itemx 750
-@itemx 505
-@option{-mno-power}, @option{-mpowerpc}, @option{-mnew-mnemonics}
-
-@item 601
-@option{-mpower}, @option{-mpowerpc}, @option{-mnew-mnemonics}
-
-@item 403
-@itemx 821
-@itemx 860
-@option{-mno-power}, @option{-mpowerpc}, @option{-mnew-mnemonics}, @option{-msoft-float}
-@end table
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use. This is
+useful when compiling kernel code. A register range is specified as
+two registers separated by a dash. Multiple register ranges can be
+specified separated by a comma.
-@item -mtune=@var{cpu_type}
+@item -mtls-size=@var{tls-size}
+@opindex mtls-size
+Specify bit size of immediate TLS offsets. Valid values are 14, 22, and
+64.
+
+@item -mtune=@var{cpu-type}
@opindex mtune
-Set the instruction scheduling parameters for machine type
-@var{cpu_type}, but do not set the architecture type, register usage, or
-choice of mnemonics, as @option{-mcpu=@var{cpu_type}} would. The same
-values for @var{cpu_type} are used for @option{-mtune} as for
-@option{-mcpu}. If both are specified, the code generated will use the
-architecture, registers, and mnemonics set by @option{-mcpu}, but the
-scheduling parameters set by @option{-mtune}.
+Tune the instruction scheduling for a particular CPU, Valid values are
+itanium, itanium1, merced, itanium2, and mckinley.
-@item -maltivec
-@itemx -mno-altivec
-@opindex maltivec
-@opindex mno-altivec
-These switches enable or disable the use of built-in functions that
-allow access to the AltiVec instruction set. You may also need to set
-@option{-mabi=altivec} to adjust the current ABI with AltiVec ABI
-enhancements.
+@item -mt
+@itemx -pthread
+@opindex mt
+@opindex pthread
+Add support for multithreading using the POSIX threads library. This
+option sets flags for both the preprocessor and linker. It does
+not affect the thread safety of object code produced by the compiler or
+that of libraries supplied with it. These are HP-UX specific flags.
+
+@item -milp32
+@itemx -mlp64
+@opindex milp32
+@opindex mlp64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits. These are HP-UX specific flags.
+
+@item -mno-sched-br-data-spec
+@itemx -msched-br-data-spec
+@opindex mno-sched-br-data-spec
+@opindex msched-br-data-spec
+(Dis/En)able data speculative scheduling before reload.
+This will result in generation of the ld.a instructions and
+the corresponding check instructions (ld.c / chk.a).
+The default is 'disable'.
+
+@item -msched-ar-data-spec
+@itemx -mno-sched-ar-data-spec
+@opindex msched-ar-data-spec
+@opindex mno-sched-ar-data-spec
+(En/Dis)able data speculative scheduling after reload.
+This will result in generation of the ld.a instructions and
+the corresponding check instructions (ld.c / chk.a).
+The default is 'enable'.
+
+@item -mno-sched-control-spec
+@itemx -msched-control-spec
+@opindex mno-sched-control-spec
+@opindex msched-control-spec
+(Dis/En)able control speculative scheduling. This feature is
+available only during region scheduling (i.e.@: before reload).
+This will result in generation of the ld.s instructions and
+the corresponding check instructions chk.s .
+The default is 'disable'.
+
+@item -msched-br-in-data-spec
+@itemx -mno-sched-br-in-data-spec
+@opindex msched-br-in-data-spec
+@opindex mno-sched-br-in-data-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the data speculative loads before reload.
+This is effective only with @option{-msched-br-data-spec} enabled.
+The default is 'enable'.
+
+@item -msched-ar-in-data-spec
+@itemx -mno-sched-ar-in-data-spec
+@opindex msched-ar-in-data-spec
+@opindex mno-sched-ar-in-data-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the data speculative loads after reload.
+This is effective only with @option{-msched-ar-data-spec} enabled.
+The default is 'enable'.
+
+@item -msched-in-control-spec
+@itemx -mno-sched-in-control-spec
+@opindex msched-in-control-spec
+@opindex mno-sched-in-control-spec
+(En/Dis)able speculative scheduling of the instructions that
+are dependent on the control speculative loads.
+This is effective only with @option{-msched-control-spec} enabled.
+The default is 'enable'.
+
+@item -msched-ldc
+@itemx -mno-sched-ldc
+@opindex msched-ldc
+@opindex mno-sched-ldc
+(En/Dis)able use of simple data speculation checks ld.c .
+If disabled, only chk.a instructions will be emitted to check
+data speculative loads.
+The default is 'enable'.
+
+@item -mno-sched-control-ldc
+@itemx -msched-control-ldc
+@opindex mno-sched-control-ldc
+@opindex msched-control-ldc
+(Dis/En)able use of ld.c instructions to check control speculative loads.
+If enabled, in case of control speculative load with no speculatively
+scheduled dependent instructions this load will be emitted as ld.sa and
+ld.c will be used to check it.
+The default is 'disable'.
+
+@item -mno-sched-spec-verbose
+@itemx -msched-spec-verbose
+@opindex mno-sched-spec-verbose
+@opindex msched-spec-verbose
+(Dis/En)able printing of the information about speculative motions.
+
+@item -mno-sched-prefer-non-data-spec-insns
+@itemx -msched-prefer-non-data-spec-insns
+@opindex mno-sched-prefer-non-data-spec-insns
+@opindex msched-prefer-non-data-spec-insns
+If enabled, data speculative instructions will be chosen for schedule
+only if there are no other choices at the moment. This will make
+the use of the data speculation much more conservative.
+The default is 'disable'.
+
+@item -mno-sched-prefer-non-control-spec-insns
+@itemx -msched-prefer-non-control-spec-insns
+@opindex mno-sched-prefer-non-control-spec-insns
+@opindex msched-prefer-non-control-spec-insns
+If enabled, control speculative instructions will be chosen for schedule
+only if there are no other choices at the moment. This will make
+the use of the control speculation much more conservative.
+The default is 'disable'.
+
+@item -mno-sched-count-spec-in-critical-path
+@itemx -msched-count-spec-in-critical-path
+@opindex mno-sched-count-spec-in-critical-path
+@opindex msched-count-spec-in-critical-path
+If enabled, speculative dependencies will be considered during
+computation of the instructions priorities. This will make the use of the
+speculation a bit more conservative.
+The default is 'disable'.
-@item -mfull-toc
-@itemx -mno-fp-in-toc
-@itemx -mno-sum-in-toc
-@itemx -mminimal-toc
-@opindex mfull-toc
-@opindex mno-fp-in-toc
-@opindex mno-sum-in-toc
-@opindex mminimal-toc
-Modify generation of the TOC (Table Of Contents), which is created for
-every executable file. The @option{-mfull-toc} option is selected by
-default. In that case, GCC will allocate at least one TOC entry for
-each unique non-automatic variable reference in your program. GCC
-will also place floating-point constants in the TOC@. However, only
-16,384 entries are available in the TOC@.
+@end table
-If you receive a linker error message that saying you have overflowed
-the available TOC space, you can reduce the amount of TOC space used
-with the @option{-mno-fp-in-toc} and @option{-mno-sum-in-toc} options.
-@option{-mno-fp-in-toc} prevents GCC from putting floating-point
-constants in the TOC and @option{-mno-sum-in-toc} forces GCC to
-generate code to calculate the sum of an address and a constant at
-run-time instead of putting that sum into the TOC@. You may specify one
-or both of these options. Each causes GCC to produce very slightly
-slower and larger code at the expense of conserving TOC space.
+@node M32C Options
+@subsection M32C Options
+@cindex M32C options
-If you still run out of space in the TOC even when you specify both of
-these options, specify @option{-mminimal-toc} instead. This option causes
-GCC to make only one TOC entry for every file. When you specify this
-option, GCC will produce code that is slower and larger but which
-uses extremely little TOC space. You may wish to use this option
-only on files that contain less frequently executed code.
+@table @gcctabopt
+@item -mcpu=@var{name}
+@opindex mcpu=
+Select the CPU for which code is generated. @var{name} may be one of
+@samp{r8c} for the R8C/Tiny series, @samp{m16c} for the M16C (up to
+/60) series, @samp{m32cm} for the M16C/80 series, or @samp{m32c} for
+the M32C/80 series.
-@item -maix64
-@itemx -maix32
-@opindex maix64
-@opindex maix32
-Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit
-@code{long} type, and the infrastructure needed to support them.
-Specifying @option{-maix64} implies @option{-mpowerpc64} and
-@option{-mpowerpc}, while @option{-maix32} disables the 64-bit ABI and
-implies @option{-mno-powerpc64}. GCC defaults to @option{-maix32}.
+@item -msim
+@opindex msim
+Specifies that the program will be run on the simulator. This causes
+an alternate runtime library to be linked in which supports, for
+example, file I/O@. You must not use this option when generating
+programs that will run on real hardware; you must provide your own
+runtime library for whatever I/O functions are needed.
+
+@item -memregs=@var{number}
+@opindex memregs=
+Specifies the number of memory-based pseudo-registers GCC will use
+during code generation. These pseudo-registers will be used like real
+registers, so there is a tradeoff between GCC's ability to fit the
+code into available registers, and the performance penalty of using
+memory instead of registers. Note that all modules in a program must
+be compiled with the same value for this option. Because of that, you
+must not use this option with the default runtime libraries gcc
+builds.
-@item -mxl-call
-@itemx -mno-xl-call
-@opindex mxl-call
-@opindex mno-xl-call
-On AIX, pass floating-point arguments to prototyped functions beyond the
-register save area (RSA) on the stack in addition to argument FPRs. The
-AIX calling convention was extended but not initially documented to
-handle an obscure K&R C case of calling a function that takes the
-address of its arguments with fewer arguments than declared. AIX XL
-compilers access floating point arguments which do not fit in the
-RSA from the stack when a subroutine is compiled without
-optimization. Because always storing floating-point arguments on the
-stack is inefficient and rarely needed, this option is not enabled by
-default and only is necessary when calling subroutines compiled by AIX
-XL compilers without optimization.
+@end table
-@item -mpe
-@opindex mpe
-Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE)@. Link an
-application written to use message passing with special startup code to
-enable the application to run. The system must have PE installed in the
-standard location (@file{/usr/lpp/ppe.poe/}), or the @file{specs} file
-must be overridden with the @option{-specs=} option to specify the
-appropriate directory location. The Parallel Environment does not
-support threads, so the @option{-mpe} option and the @option{-pthread}
-option are incompatible.
+@node M32R/D Options
+@subsection M32R/D Options
+@cindex M32R/D options
-@item -msoft-float
-@itemx -mhard-float
-@opindex msoft-float
-@opindex mhard-float
-Generate code that does not use (uses) the floating-point register set.
-Software floating point emulation is provided if you use the
-@option{-msoft-float} option, and pass the option to GCC when linking.
+These @option{-m} options are defined for Renesas M32R/D architectures:
-@item -mmultiple
-@itemx -mno-multiple
-@opindex mmultiple
-@opindex mno-multiple
-Generate code that uses (does not use) the load multiple word
-instructions and the store multiple word instructions. These
-instructions are generated by default on POWER systems, and not
-generated on PowerPC systems. Do not use @option{-mmultiple} on little
-endian PowerPC systems, since those instructions do not work when the
-processor is in little endian mode. The exceptions are PPC740 and
-PPC750 which permit the instructions usage in little endian mode.
+@table @gcctabopt
+@item -m32r2
+@opindex m32r2
+Generate code for the M32R/2@.
-@item -mstring
-@itemx -mno-string
-@opindex mstring
-@opindex mno-string
-Generate code that uses (does not use) the load string instructions
-and the store string word instructions to save multiple registers and
-do small block moves. These instructions are generated by default on
-POWER systems, and not generated on PowerPC systems. Do not use
-@option{-mstring} on little endian PowerPC systems, since those
-instructions do not work when the processor is in little endian mode.
-The exceptions are PPC740 and PPC750 which permit the instructions
-usage in little endian mode.
+@item -m32rx
+@opindex m32rx
+Generate code for the M32R/X@.
-@item -mupdate
-@itemx -mno-update
-@opindex mupdate
-@opindex mno-update
-Generate code that uses (does not use) the load or store instructions
-that update the base register to the address of the calculated memory
-location. These instructions are generated by default. If you use
-@option{-mno-update}, there is a small window between the time that the
-stack pointer is updated and the address of the previous frame is
-stored, which means code that walks the stack frame across interrupts or
-signals may get corrupted data.
+@item -m32r
+@opindex m32r
+Generate code for the M32R@. This is the default.
-@item -mfused-madd
-@itemx -mno-fused-madd
-@opindex mfused-madd
-@opindex mno-fused-madd
-Generate code that uses (does not use) the floating point multiply and
-accumulate instructions. These instructions are generated by default if
-hardware floating is used.
+@item -mmodel=small
+@opindex mmodel=small
+Assume all objects live in the lower 16MB of memory (so that their addresses
+can be loaded with the @code{ld24} instruction), and assume all subroutines
+are reachable with the @code{bl} instruction.
+This is the default.
+
+The addressability of a particular object can be set with the
+@code{model} attribute.
+
+@item -mmodel=medium
+@opindex mmodel=medium
+Assume objects may be anywhere in the 32-bit address space (the compiler
+will generate @code{seth/add3} instructions to load their addresses), and
+assume all subroutines are reachable with the @code{bl} instruction.
+
+@item -mmodel=large
+@opindex mmodel=large
+Assume objects may be anywhere in the 32-bit address space (the compiler
+will generate @code{seth/add3} instructions to load their addresses), and
+assume subroutines may not be reachable with the @code{bl} instruction
+(the compiler will generate the much slower @code{seth/add3/jl}
+instruction sequence).
+
+@item -msdata=none
+@opindex msdata=none
+Disable use of the small data area. Variables will be put into
+one of @samp{.data}, @samp{bss}, or @samp{.rodata} (unless the
+@code{section} attribute has been specified).
+This is the default.
+
+The small data area consists of sections @samp{.sdata} and @samp{.sbss}.
+Objects may be explicitly put in the small data area with the
+@code{section} attribute using one of these sections.
+
+@item -msdata=sdata
+@opindex msdata=sdata
+Put small global and static data in the small data area, but do not
+generate special code to reference them.
+
+@item -msdata=use
+@opindex msdata=use
+Put small global and static data in the small data area, and generate
+special instructions to reference them.
+
+@item -G @var{num}
+@opindex G
+@cindex smaller data references
+Put global and static objects less than or equal to @var{num} bytes
+into the small data or bss sections instead of the normal data or bss
+sections. The default value of @var{num} is 8.
+The @option{-msdata} option must be set to one of @samp{sdata} or @samp{use}
+for this option to have any effect.
+
+All modules should be compiled with the same @option{-G @var{num}} value.
+Compiling with different values of @var{num} may or may not work; if it
+doesn't the linker will give an error message---incorrect code will not be
+generated.
+
+@item -mdebug
+@opindex mdebug
+Makes the M32R specific code in the compiler display some statistics
+that might help in debugging programs.
+
+@item -malign-loops
+@opindex malign-loops
+Align all loops to a 32-byte boundary.
+
+@item -mno-align-loops
+@opindex mno-align-loops
+Do not enforce a 32-byte alignment for loops. This is the default.
+
+@item -missue-rate=@var{number}
+@opindex missue-rate=@var{number}
+Issue @var{number} instructions per cycle. @var{number} can only be 1
+or 2.
+
+@item -mbranch-cost=@var{number}
+@opindex mbranch-cost=@var{number}
+@var{number} can only be 1 or 2. If it is 1 then branches will be
+preferred over conditional code, if it is 2, then the opposite will
+apply.
+
+@item -mflush-trap=@var{number}
+@opindex mflush-trap=@var{number}
+Specifies the trap number to use to flush the cache. The default is
+12. Valid numbers are between 0 and 15 inclusive.
+
+@item -mno-flush-trap
+@opindex mno-flush-trap
+Specifies that the cache cannot be flushed by using a trap.
+
+@item -mflush-func=@var{name}
+@opindex mflush-func=@var{name}
+Specifies the name of the operating system function to call to flush
+the cache. The default is @emph{_flush_cache}, but a function call
+will only be used if a trap is not available.
+
+@item -mno-flush-func
+@opindex mno-flush-func
+Indicates that there is no OS function for flushing the cache.
+
+@end table
+
+@node M680x0 Options
+@subsection M680x0 Options
+@cindex M680x0 options
-@item -mno-bit-align
-@itemx -mbit-align
-@opindex mno-bit-align
-@opindex mbit-align
-On System V.4 and embedded PowerPC systems do not (do) force structures
-and unions that contain bit-fields to be aligned to the base type of the
-bit-field.
+These are the @samp{-m} options defined for M680x0 and ColdFire processors.
+The default settings depend on which architecture was selected when
+the compiler was configured; the defaults for the most common choices
+are given below.
-For example, by default a structure containing nothing but 8
-@code{unsigned} bit-fields of length 1 would be aligned to a 4 byte
-boundary and have a size of 4 bytes. By using @option{-mno-bit-align},
-the structure would be aligned to a 1 byte boundary and be one byte in
-size.
+@table @gcctabopt
+@item -march=@var{arch}
+@opindex march
+Generate code for a specific M680x0 or ColdFire instruction set
+architecture. Permissible values of @var{arch} for M680x0
+architectures are: @samp{68000}, @samp{68010}, @samp{68020},
+@samp{68030}, @samp{68040}, @samp{68060} and @samp{cpu32}. ColdFire
+architectures are selected according to Freescale's ISA classification
+and the permissible values are: @samp{isaa}, @samp{isaaplus},
+@samp{isab} and @samp{isac}.
+
+gcc defines a macro @samp{__mcf@var{arch}__} whenever it is generating
+code for a ColdFire target. The @var{arch} in this macro is one of the
+@option{-march} arguments given above.
+
+When used together, @option{-march} and @option{-mtune} select code
+that runs on a family of similar processors but that is optimized
+for a particular microarchitecture.
-@item -mno-strict-align
-@itemx -mstrict-align
-@opindex mno-strict-align
-@opindex mstrict-align
-On System V.4 and embedded PowerPC systems do not (do) assume that
-unaligned memory references will be handled by the system.
+@item -mcpu=@var{cpu}
+@opindex mcpu
+Generate code for a specific M680x0 or ColdFire processor.
+The M680x0 @var{cpu}s are: @samp{68000}, @samp{68010}, @samp{68020},
+@samp{68030}, @samp{68040}, @samp{68060}, @samp{68302}, @samp{68332}
+and @samp{cpu32}. The ColdFire @var{cpu}s are given by the table
+below, which also classifies the CPUs into families:
+
+@multitable @columnfractions 0.20 0.80
+@item @strong{Family} @tab @strong{@samp{-mcpu} arguments}
+@item @samp{51qe} @tab @samp{51qe}
+@item @samp{5206} @tab @samp{5202} @samp{5204} @samp{5206}
+@item @samp{5206e} @tab @samp{5206e}
+@item @samp{5208} @tab @samp{5207} @samp{5208}
+@item @samp{5211a} @tab @samp{5210a} @samp{5211a}
+@item @samp{5213} @tab @samp{5211} @samp{5212} @samp{5213}
+@item @samp{5216} @tab @samp{5214} @samp{5216}
+@item @samp{52235} @tab @samp{52230} @samp{52231} @samp{52232} @samp{52233} @samp{52234} @samp{52235}
+@item @samp{5225} @tab @samp{5224} @samp{5225}
+@item @samp{5235} @tab @samp{5232} @samp{5233} @samp{5234} @samp{5235} @samp{523x}
+@item @samp{5249} @tab @samp{5249}
+@item @samp{5250} @tab @samp{5250}
+@item @samp{5271} @tab @samp{5270} @samp{5271}
+@item @samp{5272} @tab @samp{5272}
+@item @samp{5275} @tab @samp{5274} @samp{5275}
+@item @samp{5282} @tab @samp{5280} @samp{5281} @samp{5282} @samp{528x}
+@item @samp{5307} @tab @samp{5307}
+@item @samp{5329} @tab @samp{5327} @samp{5328} @samp{5329} @samp{532x}
+@item @samp{5373} @tab @samp{5372} @samp{5373} @samp{537x}
+@item @samp{5407} @tab @samp{5407}
+@item @samp{5475} @tab @samp{5470} @samp{5471} @samp{5472} @samp{5473} @samp{5474} @samp{5475} @samp{547x} @samp{5480} @samp{5481} @samp{5482} @samp{5483} @samp{5484} @samp{5485}
+@end multitable
+
+@option{-mcpu=@var{cpu}} overrides @option{-march=@var{arch}} if
+@var{arch} is compatible with @var{cpu}. Other combinations of
+@option{-mcpu} and @option{-march} are rejected.
+
+gcc defines the macro @samp{__mcf_cpu_@var{cpu}} when ColdFire target
+@var{cpu} is selected. It also defines @samp{__mcf_family_@var{family}},
+where the value of @var{family} is given by the table above.
+
+@item -mtune=@var{tune}
+@opindex mtune
+Tune the code for a particular microarchitecture, within the
+constraints set by @option{-march} and @option{-mcpu}.
+The M680x0 microarchitectures are: @samp{68000}, @samp{68010},
+@samp{68020}, @samp{68030}, @samp{68040}, @samp{68060}
+and @samp{cpu32}. The ColdFire microarchitectures
+are: @samp{cfv1}, @samp{cfv2}, @samp{cfv3}, @samp{cfv4} and @samp{cfv4e}.
+
+You can also use @option{-mtune=68020-40} for code that needs
+to run relatively well on 68020, 68030 and 68040 targets.
+@option{-mtune=68020-60} is similar but includes 68060 targets
+as well. These two options select the same tuning decisions as
+@option{-m68020-40} and @option{-m68020-60} respectively.
+
+gcc defines the macros @samp{__mc@var{arch}} and @samp{__mc@var{arch}__}
+when tuning for 680x0 architecture @var{arch}. It also defines
+@samp{mc@var{arch}} unless either @option{-ansi} or a non-GNU @option{-std}
+option is used. If gcc is tuning for a range of architectures,
+as selected by @option{-mtune=68020-40} or @option{-mtune=68020-60},
+it defines the macros for every architecture in the range.
+
+gcc also defines the macro @samp{__m@var{uarch}__} when tuning for
+ColdFire microarchitecture @var{uarch}, where @var{uarch} is one
+of the arguments given above.
-@item -mrelocatable
-@itemx -mno-relocatable
-@opindex mrelocatable
-@opindex mno-relocatable
-On embedded PowerPC systems generate code that allows (does not allow)
-the program to be relocated to a different address at runtime. If you
-use @option{-mrelocatable} on any module, all objects linked together must
-be compiled with @option{-mrelocatable} or @option{-mrelocatable-lib}.
+@item -m68000
+@itemx -mc68000
+@opindex m68000
+@opindex mc68000
+Generate output for a 68000. This is the default
+when the compiler is configured for 68000-based systems.
+It is equivalent to @option{-march=68000}.
-@item -mrelocatable-lib
-@itemx -mno-relocatable-lib
-@opindex mrelocatable-lib
-@opindex mno-relocatable-lib
-On embedded PowerPC systems generate code that allows (does not allow)
-the program to be relocated to a different address at runtime. Modules
-compiled with @option{-mrelocatable-lib} can be linked with either modules
-compiled without @option{-mrelocatable} and @option{-mrelocatable-lib} or
-with modules compiled with the @option{-mrelocatable} options.
+Use this option for microcontrollers with a 68000 or EC000 core,
+including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356.
-@item -mno-toc
-@itemx -mtoc
-@opindex mno-toc
-@opindex mtoc
-On System V.4 and embedded PowerPC systems do not (do) assume that
-register 2 contains a pointer to a global area pointing to the addresses
-used in the program.
+@item -m68010
+@opindex m68010
+Generate output for a 68010. This is the default
+when the compiler is configured for 68010-based systems.
+It is equivalent to @option{-march=68010}.
-@item -mlittle
-@itemx -mlittle-endian
-@opindex mlittle
-@opindex mlittle-endian
-On System V.4 and embedded PowerPC systems compile code for the
-processor in little endian mode. The @option{-mlittle-endian} option is
-the same as @option{-mlittle}.
+@item -m68020
+@itemx -mc68020
+@opindex m68020
+@opindex mc68020
+Generate output for a 68020. This is the default
+when the compiler is configured for 68020-based systems.
+It is equivalent to @option{-march=68020}.
-@item -mbig
-@itemx -mbig-endian
-@opindex mbig
-@opindex mbig-endian
-On System V.4 and embedded PowerPC systems compile code for the
-processor in big endian mode. The @option{-mbig-endian} option is
-the same as @option{-mbig}.
+@item -m68030
+@opindex m68030
+Generate output for a 68030. This is the default when the compiler is
+configured for 68030-based systems. It is equivalent to
+@option{-march=68030}.
-@item -mcall-sysv
-@opindex mcall-sysv
-On System V.4 and embedded PowerPC systems compile code using calling
-conventions that adheres to the March 1995 draft of the System V
-Application Binary Interface, PowerPC processor supplement. This is the
-default unless you configured GCC using @samp{powerpc-*-eabiaix}.
+@item -m68040
+@opindex m68040
+Generate output for a 68040. This is the default when the compiler is
+configured for 68040-based systems. It is equivalent to
+@option{-march=68040}.
-@item -mcall-sysv-eabi
-@opindex mcall-sysv-eabi
-Specify both @option{-mcall-sysv} and @option{-meabi} options.
+This option inhibits the use of 68881/68882 instructions that have to be
+emulated by software on the 68040. Use this option if your 68040 does not
+have code to emulate those instructions.
-@item -mcall-sysv-noeabi
-@opindex mcall-sysv-noeabi
-Specify both @option{-mcall-sysv} and @option{-mno-eabi} options.
+@item -m68060
+@opindex m68060
+Generate output for a 68060. This is the default when the compiler is
+configured for 68060-based systems. It is equivalent to
+@option{-march=68060}.
-@item -mcall-aix
-@opindex mcall-aix
-On System V.4 and embedded PowerPC systems compile code using calling
-conventions that are similar to those used on AIX@. This is the
-default if you configured GCC using @samp{powerpc-*-eabiaix}.
+This option inhibits the use of 68020 and 68881/68882 instructions that
+have to be emulated by software on the 68060. Use this option if your 68060
+does not have code to emulate those instructions.
-@item -mcall-solaris
-@opindex mcall-solaris
-On System V.4 and embedded PowerPC systems compile code for the Solaris
-operating system.
+@item -mcpu32
+@opindex mcpu32
+Generate output for a CPU32. This is the default
+when the compiler is configured for CPU32-based systems.
+It is equivalent to @option{-march=cpu32}.
-@item -mcall-linux
-@opindex mcall-linux
-On System V.4 and embedded PowerPC systems compile code for the
-Linux-based GNU system.
+Use this option for microcontrollers with a
+CPU32 or CPU32+ core, including the 68330, 68331, 68332, 68333, 68334,
+68336, 68340, 68341, 68349 and 68360.
-@item -mcall-gnu
-@opindex mcall-gnu
-On System V.4 and embedded PowerPC systems compile code for the
-Hurd-based GNU system.
+@item -m5200
+@opindex m5200
+Generate output for a 520X ColdFire CPU@. This is the default
+when the compiler is configured for 520X-based systems.
+It is equivalent to @option{-mcpu=5206}, and is now deprecated
+in favor of that option.
-@item -mcall-netbsd
-@opindex mcall-netbsd
-On System V.4 and embedded PowerPC systems compile code for the
-NetBSD operating system.
+Use this option for microcontroller with a 5200 core, including
+the MCF5202, MCF5203, MCF5204 and MCF5206.
+
+@item -m5206e
+@opindex m5206e
+Generate output for a 5206e ColdFire CPU@. The option is now
+deprecated in favor of the equivalent @option{-mcpu=5206e}.
+
+@item -m528x
+@opindex m528x
+Generate output for a member of the ColdFire 528X family.
+The option is now deprecated in favor of the equivalent
+@option{-mcpu=528x}.
+
+@item -m5307
+@opindex m5307
+Generate output for a ColdFire 5307 CPU@. The option is now deprecated
+in favor of the equivalent @option{-mcpu=5307}.
+
+@item -m5407
+@opindex m5407
+Generate output for a ColdFire 5407 CPU@. The option is now deprecated
+in favor of the equivalent @option{-mcpu=5407}.
+
+@item -mcfv4e
+@opindex mcfv4e
+Generate output for a ColdFire V4e family CPU (e.g.@: 547x/548x).
+This includes use of hardware floating point instructions.
+The option is equivalent to @option{-mcpu=547x}, and is now
+deprecated in favor of that option.
-@item -maix-struct-return
-@opindex maix-struct-return
-Return all structures in memory (as specified by the AIX ABI)@.
+@item -m68020-40
+@opindex m68020-40
+Generate output for a 68040, without using any of the new instructions.
+This results in code which can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040. The generated code does use the
+68881 instructions that are emulated on the 68040.
-@item -msvr4-struct-return
-@opindex msvr4-struct-return
-Return structures smaller than 8 bytes in registers (as specified by the
-SVR4 ABI)@.
+The option is equivalent to @option{-march=68020} @option{-mtune=68020-40}.
-@item -mabi=altivec
-@opindex mabi=altivec
-Extend the current ABI with AltiVec ABI extensions. This does not
-change the default ABI, instead it adds the AltiVec ABI extensions to
-the current ABI@.
+@item -m68020-60
+@opindex m68020-60
+Generate output for a 68060, without using any of the new instructions.
+This results in code which can run relatively efficiently on either a
+68020/68881 or a 68030 or a 68040. The generated code does use the
+68881 instructions that are emulated on the 68060.
-@item -mabi=no-altivec
-@opindex mabi=no-altivec
-Disable AltiVec ABI extensions for the current ABI.
+The option is equivalent to @option{-march=68020} @option{-mtune=68020-60}.
-@item -mprototype
-@itemx -mno-prototype
-@opindex mprototype
-@opindex mno-prototype
-On System V.4 and embedded PowerPC systems assume that all calls to
-variable argument functions are properly prototyped. Otherwise, the
-compiler must insert an instruction before every non prototyped call to
-set or clear bit 6 of the condition code register (@var{CR}) to
-indicate whether floating point values were passed in the floating point
-registers in case the function takes a variable arguments. With
-@option{-mprototype}, only calls to prototyped variable argument functions
-will set or clear the bit.
+@item -mhard-float
+@itemx -m68881
+@opindex mhard-float
+@opindex m68881
+Generate floating-point instructions. This is the default for 68020
+and above, and for ColdFire devices that have an FPU@. It defines the
+macro @samp{__HAVE_68881__} on M680x0 targets and @samp{__mcffpu__}
+on ColdFire targets.
-@item -msim
-@opindex msim
-On embedded PowerPC systems, assume that the startup module is called
-@file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and
-@file{libc.a}. This is the default for @samp{powerpc-*-eabisim}.
-configurations.
+@item -msoft-float
+@opindex msoft-float
+Do not generate floating-point instructions; use library calls instead.
+This is the default for 68000, 68010, and 68832 targets. It is also
+the default for ColdFire devices that have no FPU.
-@item -mmvme
-@opindex mmvme
-On embedded PowerPC systems, assume that the startup module is called
-@file{crt0.o} and the standard C libraries are @file{libmvme.a} and
-@file{libc.a}.
+@item -mdiv
+@itemx -mno-div
+@opindex mdiv
+@opindex mno-div
+Generate (do not generate) ColdFire hardware divide and remainder
+instructions. If @option{-march} is used without @option{-mcpu},
+the default is ``on'' for ColdFire architectures and ``off'' for M680x0
+architectures. Otherwise, the default is taken from the target CPU
+(either the default CPU, or the one specified by @option{-mcpu}). For
+example, the default is ``off'' for @option{-mcpu=5206} and ``on'' for
+@option{-mcpu=5206e}.
-@item -mads
-@opindex mads
-On embedded PowerPC systems, assume that the startup module is called
-@file{crt0.o} and the standard C libraries are @file{libads.a} and
-@file{libc.a}.
+gcc defines the macro @samp{__mcfhwdiv__} when this option is enabled.
-@item -myellowknife
-@opindex myellowknife
-On embedded PowerPC systems, assume that the startup module is called
-@file{crt0.o} and the standard C libraries are @file{libyk.a} and
-@file{libc.a}.
+@item -mshort
+@opindex mshort
+Consider type @code{int} to be 16 bits wide, like @code{short int}.
+Additionally, parameters passed on the stack are also aligned to a
+16-bit boundary even on targets whose API mandates promotion to 32-bit.
-@item -mvxworks
-@opindex mvxworks
-On System V.4 and embedded PowerPC systems, specify that you are
-compiling for a VxWorks system.
+@item -mno-short
+@opindex mno-short
+Do not consider type @code{int} to be 16 bits wide. This is the default.
-@item -memb
-@opindex memb
-On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags
-header to indicate that @samp{eabi} extended relocations are used.
+@item -mnobitfield
+@itemx -mno-bitfield
+@opindex mnobitfield
+@opindex mno-bitfield
+Do not use the bit-field instructions. The @option{-m68000}, @option{-mcpu32}
+and @option{-m5200} options imply @w{@option{-mnobitfield}}.
-@item -meabi
-@itemx -mno-eabi
-@opindex meabi
-@opindex mno-eabi
-On System V.4 and embedded PowerPC systems do (do not) adhere to the
-Embedded Applications Binary Interface (eabi) which is a set of
-modifications to the System V.4 specifications. Selecting @option{-meabi}
-means that the stack is aligned to an 8 byte boundary, a function
-@code{__eabi} is called to from @code{main} to set up the eabi
-environment, and the @option{-msdata} option can use both @code{r2} and
-@code{r13} to point to two separate small data areas. Selecting
-@option{-mno-eabi} means that the stack is aligned to a 16 byte boundary,
-do not call an initialization function from @code{main}, and the
-@option{-msdata} option will only use @code{r13} to point to a single
-small data area. The @option{-meabi} option is on by default if you
-configured GCC using one of the @samp{powerpc*-*-eabi*} options.
+@item -mbitfield
+@opindex mbitfield
+Do use the bit-field instructions. The @option{-m68020} option implies
+@option{-mbitfield}. This is the default if you use a configuration
+designed for a 68020.
-@item -msdata=eabi
-@opindex msdata=eabi
-On System V.4 and embedded PowerPC systems, put small initialized
-@code{const} global and static data in the @samp{.sdata2} section, which
-is pointed to by register @code{r2}. Put small initialized
-non-@code{const} global and static data in the @samp{.sdata} section,
-which is pointed to by register @code{r13}. Put small uninitialized
-global and static data in the @samp{.sbss} section, which is adjacent to
-the @samp{.sdata} section. The @option{-msdata=eabi} option is
-incompatible with the @option{-mrelocatable} option. The
-@option{-msdata=eabi} option also sets the @option{-memb} option.
+@item -mrtd
+@opindex mrtd
+Use a different function-calling convention, in which functions
+that take a fixed number of arguments return with the @code{rtd}
+instruction, which pops their arguments while returning. This
+saves one instruction in the caller since there is no need to pop
+the arguments there.
-@item -msdata=sysv
-@opindex msdata=sysv
-On System V.4 and embedded PowerPC systems, put small global and static
-data in the @samp{.sdata} section, which is pointed to by register
-@code{r13}. Put small uninitialized global and static data in the
-@samp{.sbss} section, which is adjacent to the @samp{.sdata} section.
-The @option{-msdata=sysv} option is incompatible with the
-@option{-mrelocatable} option.
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
-@item -msdata=default
-@itemx -msdata
-@opindex msdata=default
-@opindex msdata
-On System V.4 and embedded PowerPC systems, if @option{-meabi} is used,
-compile code the same as @option{-msdata=eabi}, otherwise compile code the
-same as @option{-msdata=sysv}.
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including @code{printf});
+otherwise incorrect code will be generated for calls to those
+functions.
-@item -msdata-data
-@opindex msdata-data
-On System V.4 and embedded PowerPC systems, put small global and static
-data in the @samp{.sdata} section. Put small uninitialized global and
-static data in the @samp{.sbss} section. Do not use register @code{r13}
-to address small data however. This is the default behavior unless
-other @option{-msdata} options are used.
+In addition, seriously incorrect code will result if you call a
+function with too many arguments. (Normally, extra arguments are
+harmlessly ignored.)
-@item -msdata=none
-@itemx -mno-sdata
-@opindex msdata=none
-@opindex mno-sdata
-On embedded PowerPC systems, put all initialized global and static data
-in the @samp{.data} section, and all uninitialized data in the
-@samp{.bss} section.
+The @code{rtd} instruction is supported by the 68010, 68020, 68030,
+68040, 68060 and CPU32 processors, but not by the 68000 or 5200.
-@item -G @var{num}
-@opindex G
-@cindex smaller data references (PowerPC)
-@cindex .sdata/.sdata2 references (PowerPC)
-On embedded PowerPC systems, put global and static items less than or
-equal to @var{num} bytes into the small data or bss sections instead of
-the normal data or bss section. By default, @var{num} is 8. The
-@option{-G @var{num}} switch is also passed to the linker.
-All modules should be compiled with the same @option{-G @var{num}} value.
+@item -mno-rtd
+@opindex mno-rtd
+Do not use the calling conventions selected by @option{-mrtd}.
+This is the default.
-@item -mregnames
-@itemx -mno-regnames
-@opindex mregnames
-@opindex mno-regnames
-On System V.4 and embedded PowerPC systems do (do not) emit register
-names in the assembly language output using symbolic forms.
+@item -malign-int
+@itemx -mno-align-int
+@opindex malign-int
+@opindex mno-align-int
+Control whether GCC aligns @code{int}, @code{long}, @code{long long},
+@code{float}, @code{double}, and @code{long double} variables on a 32-bit
+boundary (@option{-malign-int}) or a 16-bit boundary (@option{-mno-align-int}).
+Aligning variables on 32-bit boundaries produces code that runs somewhat
+faster on processors with 32-bit busses at the expense of more memory.
-@item -pthread
-@opindex pthread
-Adds support for multithreading with the @dfn{pthreads} library.
-This option sets flags for both the preprocessor and linker.
+@strong{Warning:} if you use the @option{-malign-int} switch, GCC will
+align structures containing the above types differently than
+most published application binary interface specifications for the m68k.
-@end table
+@item -mpcrel
+@opindex mpcrel
+Use the pc-relative addressing mode of the 68000 directly, instead of
+using a global offset table. At present, this option implies @option{-fpic},
+allowing at most a 16-bit offset for pc-relative addressing. @option{-fPIC} is
+not presently supported with @option{-mpcrel}, though this could be supported for
+68020 and higher processors.
-@node RT Options
-@subsection IBM RT Options
-@cindex RT options
-@cindex IBM RT options
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+Do not (do) assume that unaligned memory references will be handled by
+the system.
-These @samp{-m} options are defined for the IBM RT PC:
+@item -msep-data
+Generate code that allows the data segment to be located in a different
+area of memory from the text segment. This allows for execute in place in
+an environment without virtual memory management. This option implies
+@option{-fPIC}.
-@table @gcctabopt
-@item -min-line-mul
-@opindex min-line-mul
-Use an in-line code sequence for integer multiplies. This is the
-default.
+@item -mno-sep-data
+Generate code that assumes that the data segment follows the text segment.
+This is the default.
-@item -mcall-lib-mul
-@opindex mcall-lib-mul
-Call @code{lmul$$} for integer multiples.
-
-@item -mfull-fp-blocks
-@opindex mfull-fp-blocks
-Generate full-size floating point data blocks, including the minimum
-amount of scratch space recommended by IBM@. This is the default.
-
-@item -mminimum-fp-blocks
-@opindex mminimum-fp-blocks
-Do not include extra scratch space in floating point data blocks. This
-results in smaller code, but slower execution, since scratch space must
-be allocated dynamically.
-
-@cindex @file{varargs.h} and RT PC
-@cindex @file{stdarg.h} and RT PC
-@item -mfp-arg-in-fpregs
-@opindex mfp-arg-in-fpregs
-Use a calling sequence incompatible with the IBM calling convention in
-which floating point arguments are passed in floating point registers.
-Note that @code{varargs.h} and @code{stdarg.h} will not work with
-floating point operands if this option is specified.
-
-@item -mfp-arg-in-gregs
-@opindex mfp-arg-in-gregs
-Use the normal calling convention for floating point arguments. This is
-the default.
-
-@item -mhc-struct-return
-@opindex mhc-struct-return
-Return structures of more than one word in memory, rather than in a
-register. This provides compatibility with the MetaWare HighC (hc)
-compiler. Use the option @option{-fpcc-struct-return} for compatibility
-with the Portable C Compiler (pcc).
-
-@item -mnohc-struct-return
-@opindex mnohc-struct-return
-Return some structures of more than one word in registers, when
-convenient. This is the default. For compatibility with the
-IBM-supplied compilers, use the option @option{-fpcc-struct-return} or the
-option @option{-mhc-struct-return}.
-@end table
+@item -mid-shared-library
+Generate code that supports shared libraries via the library ID method.
+This allows for execute in place and shared libraries in an environment
+without virtual memory management. This option implies @option{-fPIC}.
-@node MIPS Options
-@subsection MIPS Options
-@cindex MIPS options
+@item -mno-id-shared-library
+Generate code that doesn't assume ID based shared libraries are being used.
+This is the default.
-These @samp{-m} options are defined for the MIPS family of computers:
+@item -mshared-library-id=n
+Specified the identification number of the ID based shared library being
+compiled. Specifying a value of 0 will generate more compact code, specifying
+other values will force the allocation of that number to the current
+library but is no more space or time efficient than omitting this option.
+
+@item -mxgot
+@itemx -mno-xgot
+@opindex mxgot
+@opindex mno-xgot
+When generating position-independent code for ColdFire, generate code
+that works if the GOT has more than 8192 entries. This code is
+larger and slower than code generated without this option. On M680x0
+processors, this option is not needed; @option{-fPIC} suffices.
+
+GCC normally uses a single instruction to load values from the GOT@.
+While this is relatively efficient, it only works if the GOT
+is smaller than about 64k. Anything larger causes the linker
+to report an error such as:
+
+@cindex relocation truncated to fit (ColdFire)
+@smallexample
+relocation truncated to fit: R_68K_GOT16O foobar
+@end smallexample
-@table @gcctabopt
+If this happens, you should recompile your code with @option{-mxgot}.
+It should then work with very large GOTs. However, code generated with
+@option{-mxgot} is less efficient, since it takes 4 instructions to fetch
+the value of a global symbol.
-@item -march=@var{cpu-type}
-@opindex march
-Assume the defaults for the machine type @var{cpu-type} when generating
-instructions. The choices for @var{cpu-type} are @samp{r2000}, @samp{r3000},
-@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400},
-@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000},
-and @samp{orion}. Additionally, the @samp{r2000}, @samp{r3000},
-@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as
-@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc.
+Note that some linkers, including newer versions of the GNU linker,
+can create multiple GOTs and sort GOT entries. If you have such a linker,
+you should only need to use @option{-mxgot} when compiling a single
+object file that accesses more than 8192 GOT entries. Very few do.
-@item -mtune=@var{cpu-type}
-@opindex mtune
-Assume the defaults for the machine type @var{cpu-type} when scheduling
-instructions. The choices for @var{cpu-type} are @samp{r2000}, @samp{r3000},
-@samp{r3900}, @samp{r4000}, @samp{r4100}, @samp{r4300}, @samp{r4400},
-@samp{r4600}, @samp{r4650}, @samp{r5000}, @samp{r6000}, @samp{r8000},
-and @samp{orion}. Additionally, the @samp{r2000}, @samp{r3000},
-@samp{r4000}, @samp{r5000}, and @samp{r6000} can be abbreviated as
-@samp{r2k} (or @samp{r2K}), @samp{r3k}, etc. While picking a specific
-@var{cpu-type} will schedule things appropriately for that particular
-chip, the compiler will not generate any code that does not meet level 1
-of the MIPS ISA (instruction set architecture) without a @option{-mipsX}
-or @option{-mabi} switch being used.
+These options have no effect unless GCC is generating
+position-independent code.
-@item -mcpu=@var{cpu-type}
-@opindex mcpu
-This is identical to specifying both @option{-march} and @option{-mtune}.
+@end table
-@item -mips1
-@opindex mips1
-Issue instructions from level 1 of the MIPS ISA@. This is the default.
-@samp{r3000} is the default @var{cpu-type} at this ISA level.
+@node M68hc1x Options
+@subsection M68hc1x Options
+@cindex M68hc1x options
-@item -mips2
-@opindex mips2
-Issue instructions from level 2 of the MIPS ISA (branch likely, square
-root instructions). @samp{r6000} is the default @var{cpu-type} at this
-ISA level.
+These are the @samp{-m} options defined for the 68hc11 and 68hc12
+microcontrollers. The default values for these options depends on
+which style of microcontroller was selected when the compiler was configured;
+the defaults for the most common choices are given below.
-@item -mips3
-@opindex mips3
-Issue instructions from level 3 of the MIPS ISA (64-bit instructions).
-@samp{r4000} is the default @var{cpu-type} at this ISA level.
+@table @gcctabopt
+@item -m6811
+@itemx -m68hc11
+@opindex m6811
+@opindex m68hc11
+Generate output for a 68HC11. This is the default
+when the compiler is configured for 68HC11-based systems.
-@item -mips4
-@opindex mips4
-Issue instructions from level 4 of the MIPS ISA (conditional move,
-prefetch, enhanced FPU instructions). @samp{r8000} is the default
-@var{cpu-type} at this ISA level.
+@item -m6812
+@itemx -m68hc12
+@opindex m6812
+@opindex m68hc12
+Generate output for a 68HC12. This is the default
+when the compiler is configured for 68HC12-based systems.
-@item -mfp32
-@opindex mfp32
-Assume that 32 32-bit floating point registers are available. This is
-the default.
+@item -m68S12
+@itemx -m68hcs12
+@opindex m68S12
+@opindex m68hcs12
+Generate output for a 68HCS12.
-@item -mfp64
-@opindex mfp64
-Assume that 32 64-bit floating point registers are available. This is
-the default when the @option{-mips3} option is used.
+@item -mauto-incdec
+@opindex mauto-incdec
+Enable the use of 68HC12 pre and post auto-increment and auto-decrement
+addressing modes.
-@item -mfused-madd
-@itemx -mno-fused-madd
-@opindex mfused-madd
-@opindex mno-fused-madd
-Generate code that uses (does not use) the floating point multiply and
-accumulate instructions, when they are available. These instructions
-are generated by default if they are available, but this may be
-undesirable if the extra precision causes problems or on certain chips
-in the mode where denormals are rounded to zero where denormals
-generated by multiply and accumulate instructions cause exceptions
-anyway.
+@item -minmax
+@itemx -nominmax
+@opindex minmax
+@opindex mnominmax
+Enable the use of 68HC12 min and max instructions.
-@item -mgp32
-@opindex mgp32
-Assume that 32 32-bit general purpose registers are available. This is
-the default.
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Treat all calls as being far away (near). If calls are assumed to be
+far away, the compiler will use the @code{call} instruction to
+call a function and the @code{rtc} instruction for returning.
-@item -mgp64
-@opindex mgp64
-Assume that 32 64-bit general purpose registers are available. This is
-the default when the @option{-mips3} option is used.
+@item -mshort
+@opindex mshort
+Consider type @code{int} to be 16 bits wide, like @code{short int}.
-@item -mint64
-@opindex mint64
-Force int and long types to be 64 bits wide. See @option{-mlong32} for an
-explanation of the default, and the width of pointers.
+@item -msoft-reg-count=@var{count}
+@opindex msoft-reg-count
+Specify the number of pseudo-soft registers which are used for the
+code generation. The maximum number is 32. Using more pseudo-soft
+register may or may not result in better code depending on the program.
+The default is 4 for 68HC11 and 2 for 68HC12.
-@item -mlong64
-@opindex mlong64
-Force long types to be 64 bits wide. See @option{-mlong32} for an
-explanation of the default, and the width of pointers.
+@end table
-@item -mlong32
-@opindex mlong32
-Force long, int, and pointer types to be 32 bits wide.
-
-If none of @option{-mlong32}, @option{-mlong64}, or @option{-mint64} are set,
-the size of ints, longs, and pointers depends on the ABI and ISA chosen.
-For @option{-mabi=32}, and @option{-mabi=n32}, ints and longs are 32 bits
-wide. For @option{-mabi=64}, ints are 32 bits, and longs are 64 bits wide.
-For @option{-mabi=eabi} and either @option{-mips1} or @option{-mips2}, ints
-and longs are 32 bits wide. For @option{-mabi=eabi} and higher ISAs, ints
-are 32 bits, and longs are 64 bits wide. The width of pointer types is
-the smaller of the width of longs or the width of general purpose
-registers (which in turn depends on the ISA)@.
+@node MCore Options
+@subsection MCore Options
+@cindex MCore options
-@item -mabi=32
-@itemx -mabi=o64
-@itemx -mabi=n32
-@itemx -mabi=64
-@itemx -mabi=eabi
-@opindex mabi=32
-@opindex mabi=o64
-@opindex mabi=n32
-@opindex mabi=64
-@opindex mabi=eabi
-Generate code for the indicated ABI@. The default instruction level is
-@option{-mips1} for @samp{32}, @option{-mips3} for @samp{n32}, and
-@option{-mips4} otherwise. Conversely, with @option{-mips1} or
-@option{-mips2}, the default ABI is @samp{32}; otherwise, the default ABI
-is @samp{64}.
-
-@item -mmips-as
-@opindex mmips-as
-Generate code for the MIPS assembler, and invoke @file{mips-tfile} to
-add normal debug information. This is the default for all
-platforms except for the OSF/1 reference platform, using the OSF/rose
-object format. If the either of the @option{-gstabs} or @option{-gstabs+}
-switches are used, the @file{mips-tfile} program will encapsulate the
-stabs within MIPS ECOFF@.
+These are the @samp{-m} options defined for the Motorola M*Core
+processors.
-@item -mgas
-@opindex mgas
-Generate code for the GNU assembler. This is the default on the OSF/1
-reference platform, using the OSF/rose object format. Also, this is
-the default if the configure option @option{--with-gnu-as} is used.
+@table @gcctabopt
-@item -msplit-addresses
-@itemx -mno-split-addresses
-@opindex msplit-addresses
-@opindex mno-split-addresses
-Generate code to load the high and low parts of address constants separately.
-This allows GCC to optimize away redundant loads of the high order
-bits of addresses. This optimization requires GNU as and GNU ld.
-This optimization is enabled by default for some embedded targets where
-GNU as and GNU ld are standard.
-
-@item -mrnames
-@itemx -mno-rnames
-@opindex mrnames
-@opindex mno-rnames
-The @option{-mrnames} switch says to output code using the MIPS software
-names for the registers, instead of the hardware names (ie, @var{a0}
-instead of @var{$4}). The only known assembler that supports this option
-is the Algorithmics assembler.
+@item -mhardlit
+@itemx -mno-hardlit
+@opindex mhardlit
+@opindex mno-hardlit
+Inline constants into the code stream if it can be done in two
+instructions or less.
-@item -mgpopt
-@itemx -mno-gpopt
-@opindex mgpopt
-@opindex mno-gpopt
-The @option{-mgpopt} switch says to write all of the data declarations
-before the instructions in the text section, this allows the MIPS
-assembler to generate one word memory references instead of using two
-words for short global or static data items. This is on by default if
-optimization is selected.
-
-@item -mstats
-@itemx -mno-stats
-@opindex mstats
-@opindex mno-stats
-For each non-inline function processed, the @option{-mstats} switch
-causes the compiler to emit one line to the standard error file to
-print statistics about the program (number of registers saved, stack
-size, etc.).
+@item -mdiv
+@itemx -mno-div
+@opindex mdiv
+@opindex mno-div
+Use the divide instruction. (Enabled by default).
-@item -mmemcpy
-@itemx -mno-memcpy
-@opindex mmemcpy
-@opindex mno-memcpy
-The @option{-mmemcpy} switch makes all block moves call the appropriate
-string function (@samp{memcpy} or @samp{bcopy}) instead of possibly
-generating inline code.
-
-@item -mmips-tfile
-@itemx -mno-mips-tfile
-@opindex mmips-tfile
-@opindex mno-mips-tfile
-The @option{-mno-mips-tfile} switch causes the compiler not
-postprocess the object file with the @file{mips-tfile} program,
-after the MIPS assembler has generated it to add debug support. If
-@file{mips-tfile} is not run, then no local variables will be
-available to the debugger. In addition, @file{stage2} and
-@file{stage3} objects will have the temporary file names passed to the
-assembler embedded in the object file, which means the objects will
-not compare the same. The @option{-mno-mips-tfile} switch should only
-be used when there are bugs in the @file{mips-tfile} program that
-prevents compilation.
+@item -mrelax-immediate
+@itemx -mno-relax-immediate
+@opindex mrelax-immediate
+@opindex mno-relax-immediate
+Allow arbitrary sized immediates in bit operations.
-@item -msoft-float
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not part of GCC@.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
+@item -mwide-bitfields
+@itemx -mno-wide-bitfields
+@opindex mwide-bitfields
+@opindex mno-wide-bitfields
+Always treat bit-fields as int-sized.
-@item -mhard-float
-@opindex mhard-float
-Generate output containing floating point instructions. This is the
-default if you use the unmodified sources.
+@item -m4byte-functions
+@itemx -mno-4byte-functions
+@opindex m4byte-functions
+@opindex mno-4byte-functions
+Force all functions to be aligned to a four byte boundary.
-@item -mabicalls
-@itemx -mno-abicalls
-@opindex mabicalls
-@opindex mno-abicalls
-Emit (or do not emit) the pseudo operations @samp{.abicalls},
-@samp{.cpload}, and @samp{.cprestore} that some System V.4 ports use for
-position independent code.
+@item -mcallgraph-data
+@itemx -mno-callgraph-data
+@opindex mcallgraph-data
+@opindex mno-callgraph-data
+Emit callgraph information.
-@item -mlong-calls
-@itemx -mno-long-calls
-@opindex mlong-calls
-@opindex mno-long-calls
-Do all calls with the @samp{JALR} instruction, which requires
-loading up a function's address into a register before the call.
-You need to use this switch, if you call outside of the current
-512 megabyte segment to functions that are not through pointers.
-
-@item -mhalf-pic
-@itemx -mno-half-pic
-@opindex mhalf-pic
-@opindex mno-half-pic
-Put pointers to extern references into the data section and load them
-up, rather than put the references in the text section.
-
-@item -membedded-pic
-@itemx -mno-embedded-pic
-@opindex membedded-pic
-@opindex mno-embedded-pic
-Generate PIC code suitable for some embedded systems. All calls are
-made using PC relative address, and all data is addressed using the $gp
-register. No more than 65536 bytes of global data may be used. This
-requires GNU as and GNU ld which do most of the work. This currently
-only works on targets which use ECOFF; it does not work with ELF@.
+@item -mslow-bytes
+@itemx -mno-slow-bytes
+@opindex mslow-bytes
+@opindex mno-slow-bytes
+Prefer word access when reading byte quantities.
-@item -membedded-data
-@itemx -mno-embedded-data
-@opindex membedded-data
-@opindex mno-embedded-data
-Allocate variables to the read-only data section first if possible, then
-next in the small data section if possible, otherwise in data. This gives
-slightly slower code than the default, but reduces the amount of RAM required
-when executing, and thus may be preferred for some embedded systems.
+@item -mlittle-endian
+@itemx -mbig-endian
+@opindex mlittle-endian
+@opindex mbig-endian
+Generate code for a little endian target.
+
+@item -m210
+@itemx -m340
+@opindex m210
+@opindex m340
+Generate code for the 210 processor.
-@item -muninit-const-in-rodata
-@itemx -mno-uninit-const-in-rodata
-@opindex muninit-const-in-rodata
-@opindex mno-uninit-const-in-rodata
-When used together with @option{-membedded-data}, it will always store uninitialized
-const variables in the read-only data section.
+@item -mno-lsim
+@opindex no-lsim
+Assume that run-time support has been provided and so omit the
+simulator library (@file{libsim.a)} from the linker command line.
-@item -msingle-float
-@itemx -mdouble-float
-@opindex msingle-float
-@opindex mdouble-float
-The @option{-msingle-float} switch tells gcc to assume that the floating
-point coprocessor only supports single precision operations, as on the
-@samp{r4650} chip. The @option{-mdouble-float} switch permits gcc to use
-double precision operations. This is the default.
+@item -mstack-increment=@var{size}
+@opindex mstack-increment
+Set the maximum amount for a single stack increment operation. Large
+values can increase the speed of programs which contain functions
+that need a large amount of stack space, but they can also trigger a
+segmentation fault if the stack is extended too much. The default
+value is 0x1000.
-@item -mmad
-@itemx -mno-mad
-@opindex mmad
-@opindex mno-mad
-Permit use of the @samp{mad}, @samp{madu} and @samp{mul} instructions,
-as on the @samp{r4650} chip.
+@end table
-@item -m4650
-@opindex m4650
-Turns on @option{-msingle-float}, @option{-mmad}, and, at least for now,
-@option{-mcpu=r4650}.
+@node MIPS Options
+@subsection MIPS Options
+@cindex MIPS options
-@item -mips16
-@itemx -mno-mips16
-@opindex mips16
-@opindex mno-mips16
-Enable 16-bit instructions.
+@table @gcctabopt
-@item -mentry
-@opindex mentry
-Use the entry and exit pseudo ops. This option can only be used with
-@option{-mips16}.
+@item -EB
+@opindex EB
+Generate big-endian code.
@item -EL
@opindex EL
-Compile code for the processor in little endian mode.
-The requisite libraries are assumed to exist.
+Generate little-endian code. This is the default for @samp{mips*el-*-*}
+configurations.
-@item -EB
-@opindex EB
-Compile code for the processor in big endian mode.
-The requisite libraries are assumed to exist.
+@item -march=@var{arch}
+@opindex march
+Generate code that will run on @var{arch}, which can be the name of a
+generic MIPS ISA, or the name of a particular processor.
+The ISA names are:
+@samp{mips1}, @samp{mips2}, @samp{mips3}, @samp{mips4},
+@samp{mips32}, @samp{mips32r2}, @samp{mips64} and @samp{mips64r2}.
+The processor names are:
+@samp{4kc}, @samp{4km}, @samp{4kp}, @samp{4ksc},
+@samp{4kec}, @samp{4kem}, @samp{4kep}, @samp{4ksd},
+@samp{5kc}, @samp{5kf},
+@samp{20kc},
+@samp{24kc}, @samp{24kf2_1}, @samp{24kf1_1},
+@samp{24kec}, @samp{24kef2_1}, @samp{24kef1_1},
+@samp{34kc}, @samp{34kf2_1}, @samp{34kf1_1},
+@samp{74kc}, @samp{74kf2_1}, @samp{74kf1_1}, @samp{74kf3_2},
+@samp{loongson2e}, @samp{loongson2f},
+@samp{m4k},
+@samp{octeon},
+@samp{orion},
+@samp{r2000}, @samp{r3000}, @samp{r3900}, @samp{r4000}, @samp{r4400},
+@samp{r4600}, @samp{r4650}, @samp{r6000}, @samp{r8000},
+@samp{rm7000}, @samp{rm9000},
+@samp{r10000}, @samp{r12000}, @samp{r14000}, @samp{r16000},
+@samp{sb1},
+@samp{sr71000},
+@samp{vr4100}, @samp{vr4111}, @samp{vr4120}, @samp{vr4130}, @samp{vr4300},
+@samp{vr5000}, @samp{vr5400}, @samp{vr5500}
+and @samp{xlr}.
+The special value @samp{from-abi} selects the
+most compatible architecture for the selected ABI (that is,
+@samp{mips1} for 32-bit ABIs and @samp{mips3} for 64-bit ABIs)@.
+
+Native Linux/GNU toolchains also support the value @samp{native},
+which selects the best architecture option for the host processor.
+@option{-march=native} has no effect if GCC does not recognize
+the processor.
+
+In processor names, a final @samp{000} can be abbreviated as @samp{k}
+(for example, @samp{-march=r2k}). Prefixes are optional, and
+@samp{vr} may be written @samp{r}.
+
+Names of the form @samp{@var{n}f2_1} refer to processors with
+FPUs clocked at half the rate of the core, names of the form
+@samp{@var{n}f1_1} refer to processors with FPUs clocked at the same
+rate as the core, and names of the form @samp{@var{n}f3_2} refer to
+processors with FPUs clocked a ratio of 3:2 with respect to the core.
+For compatibility reasons, @samp{@var{n}f} is accepted as a synonym
+for @samp{@var{n}f2_1} while @samp{@var{n}x} and @samp{@var{b}fx} are
+accepted as synonyms for @samp{@var{n}f1_1}.
+
+GCC defines two macros based on the value of this option. The first
+is @samp{_MIPS_ARCH}, which gives the name of target architecture, as
+a string. The second has the form @samp{_MIPS_ARCH_@var{foo}},
+where @var{foo} is the capitalized value of @samp{_MIPS_ARCH}@.
+For example, @samp{-march=r2000} will set @samp{_MIPS_ARCH}
+to @samp{"r2000"} and define the macro @samp{_MIPS_ARCH_R2000}.
+
+Note that the @samp{_MIPS_ARCH} macro uses the processor names given
+above. In other words, it will have the full prefix and will not
+abbreviate @samp{000} as @samp{k}. In the case of @samp{from-abi},
+the macro names the resolved architecture (either @samp{"mips1"} or
+@samp{"mips3"}). It names the default architecture when no
+@option{-march} option is given.
+
+@item -mtune=@var{arch}
+@opindex mtune
+Optimize for @var{arch}. Among other things, this option controls
+the way instructions are scheduled, and the perceived cost of arithmetic
+operations. The list of @var{arch} values is the same as for
+@option{-march}.
-@item -G @var{num}
-@opindex G
-@cindex smaller data references (MIPS)
-@cindex gp-relative references (MIPS)
-Put global and static items less than or equal to @var{num} bytes into
-the small data or bss sections instead of the normal data or bss
-section. This allows the assembler to emit one word memory reference
-instructions based on the global pointer (@var{gp} or @var{$28}),
-instead of the normal two words used. By default, @var{num} is 8 when
-the MIPS assembler is used, and 0 when the GNU assembler is used. The
-@option{-G @var{num}} switch is also passed to the assembler and linker.
-All modules should be compiled with the same @option{-G @var{num}}
-value.
+When this option is not used, GCC will optimize for the processor
+specified by @option{-march}. By using @option{-march} and
+@option{-mtune} together, it is possible to generate code that will
+run on a family of processors, but optimize the code for one
+particular member of that family.
-@item -nocpp
-@opindex nocpp
-Tell the MIPS assembler to not run its preprocessor over user
-assembler files (with a @samp{.s} suffix) when assembling them.
+@samp{-mtune} defines the macros @samp{_MIPS_TUNE} and
+@samp{_MIPS_TUNE_@var{foo}}, which work in the same way as the
+@samp{-march} ones described above.
-@item -mfix7000
-@opindex mfix7000
-Pass an option to gas which will cause nops to be inserted if
-the read of the destination register of an mfhi or mflo instruction
-occurs in the following two instructions.
+@item -mips1
+@opindex mips1
+Equivalent to @samp{-march=mips1}.
-@item -no-crt0
-@opindex no-crt0
-Do not include the default crt0.
+@item -mips2
+@opindex mips2
+Equivalent to @samp{-march=mips2}.
-@item -mflush-func=@var{func}
-@itemx -mno-flush-func
-@opindex mflush-func
-Specifies the function to call to flush the I and D caches, or to not
-call any such function. If called, the function must take the same
-arguments as the common @code{_flush_func()}, that is, the address of the
-memory range for which the cache is being flushed, the size of the
-memory range, and the number 3 (to flush both caches). The default
-depends on the target gcc was configured for, but commonly is either
-@samp{_flush_func} or @samp{__cpu_flush}.
-@end table
+@item -mips3
+@opindex mips3
+Equivalent to @samp{-march=mips3}.
-These options are defined by the macro
-@code{TARGET_SWITCHES} in the machine description. The default for the
-options is also defined by that macro, which enables you to change the
-defaults.
+@item -mips4
+@opindex mips4
+Equivalent to @samp{-march=mips4}.
-@node i386 and x86-64 Options
-@subsection Intel 386 and AMD x86-64 Options
-@cindex i386 Options
-@cindex x86-64 Options
-@cindex Intel 386 Options
-@cindex AMD x86-64 Options
+@item -mips32
+@opindex mips32
+Equivalent to @samp{-march=mips32}.
-These @samp{-m} options are defined for the i386 and x86-64 family of
-computers:
+@item -mips32r2
+@opindex mips32r2
+Equivalent to @samp{-march=mips32r2}.
-@table @gcctabopt
-@item -mcpu=@var{cpu-type}
-@opindex mcpu
-Tune to @var{cpu-type} everything applicable about the generated code, except
-for the ABI and the set of available instructions. The choices for
-@var{cpu-type} are @samp{i386}, @samp{i486}, @samp{i586}, @samp{i686},
-@samp{pentium}, @samp{pentium-mmx}, @samp{pentiumpro}, @samp{pentium2},
-@samp{pentium3}, @samp{pentium4}, @samp{k6}, @samp{k6-2}, @samp{k6-3},
-@samp{athlon}, @samp{athlon-tbird}, @samp{athlon-4}, @samp{athlon-xp}
-and @samp{athlon-mp}.
+@item -mips64
+@opindex mips64
+Equivalent to @samp{-march=mips64}.
-While picking a specific @var{cpu-type} will schedule things appropriately
-for that particular chip, the compiler will not generate any code that
-does not run on the i386 without the @option{-march=@var{cpu-type}} option
-being used. @samp{i586} is equivalent to @samp{pentium} and @samp{i686}
-is equivalent to @samp{pentiumpro}. @samp{k6} and @samp{athlon} are the
-AMD chips as opposed to the Intel ones.
+@item -mips64r2
+@opindex mips64r2
+Equivalent to @samp{-march=mips64r2}.
-@item -march=@var{cpu-type}
-@opindex march
-Generate instructions for the machine type @var{cpu-type}. The choices
-for @var{cpu-type} are the same as for @option{-mcpu}. Moreover,
-specifying @option{-march=@var{cpu-type}} implies @option{-mcpu=@var{cpu-type}}.
-
-@item -m386
-@itemx -m486
-@itemx -mpentium
-@itemx -mpentiumpro
-@opindex m386
-@opindex m486
-@opindex mpentium
-@opindex mpentiumpro
-These options are synonyms for @option{-mcpu=i386}, @option{-mcpu=i486},
-@option{-mcpu=pentium}, and @option{-mcpu=pentiumpro} respectively.
-These synonyms are deprecated.
+@item -mips16
+@itemx -mno-mips16
+@opindex mips16
+@opindex mno-mips16
+Generate (do not generate) MIPS16 code. If GCC is targetting a
+MIPS32 or MIPS64 architecture, it will make use of the MIPS16e ASE@.
+
+MIPS16 code generation can also be controlled on a per-function basis
+by means of @code{mips16} and @code{nomips16} attributes.
+@xref{Function Attributes}, for more information.
+
+@item -mflip-mips16
+@opindex mflip-mips16
+Generate MIPS16 code on alternating functions. This option is provided
+for regression testing of mixed MIPS16/non-MIPS16 code generation, and is
+not intended for ordinary use in compiling user code.
+
+@item -minterlink-mips16
+@itemx -mno-interlink-mips16
+@opindex minterlink-mips16
+@opindex mno-interlink-mips16
+Require (do not require) that non-MIPS16 code be link-compatible with
+MIPS16 code.
+
+For example, non-MIPS16 code cannot jump directly to MIPS16 code;
+it must either use a call or an indirect jump. @option{-minterlink-mips16}
+therefore disables direct jumps unless GCC knows that the target of the
+jump is not MIPS16.
-@item -mfpmath=@var{unit}
-@opindex march
-generate floating point arithmetics for selected unit @var{unit}. the choices
-for @var{unit} are:
+@item -mabi=32
+@itemx -mabi=o64
+@itemx -mabi=n32
+@itemx -mabi=64
+@itemx -mabi=eabi
+@opindex mabi=32
+@opindex mabi=o64
+@opindex mabi=n32
+@opindex mabi=64
+@opindex mabi=eabi
+Generate code for the given ABI@.
-@table @samp
-@item 387
-Use the standard 387 floating point coprocessor present majority of chips and
-emulated otherwise. Code compiled with this option will run almost everywhere.
-The temporary results are computed in 80bit precesion instead of precision
-specified by the type resulting in slightly different results compared to most
-of other chips. See @option{-ffloat-store} for more detailed description.
+Note that the EABI has a 32-bit and a 64-bit variant. GCC normally
+generates 64-bit code when you select a 64-bit architecture, but you
+can use @option{-mgp32} to get 32-bit code instead.
-This is the default choice for i386 compiler.
+For information about the O64 ABI, see
+@w{@uref{http://gcc.gnu.org/projects/mipso64-abi.html}}.
-@item sse
-Use scalar floating point instructions present in the SSE instruction set.
-This instruction set is supported by Pentium3 and newer chips, in the AMD line
-by Athlon-4, Athlon-xp and Athlon-mp chips. The earlier version of SSE
-instruction set supports only single precision arithmetics, thus the double and
-extended precision arithmetics is still done using 387. Later version, present
-only in Pentium4 and the future AMD x86-64 chips supports double precision
-arithmetics too.
+GCC supports a variant of the o32 ABI in which floating-point registers
+are 64 rather than 32 bits wide. You can select this combination with
+@option{-mabi=32} @option{-mfp64}. This ABI relies on the @samp{mthc1}
+and @samp{mfhc1} instructions and is therefore only supported for
+MIPS32R2 processors.
-For i387 you need to use @option{-march=@var{cpu-type}}, @option{-msse} or
-@option{-msse2} switches to enable SSE extensions and make this option
-effective. For x86-64 compiler, these extensions are enabled by default.
+The register assignments for arguments and return values remain the
+same, but each scalar value is passed in a single 64-bit register
+rather than a pair of 32-bit registers. For example, scalar
+floating-point values are returned in @samp{$f0} only, not a
+@samp{$f0}/@samp{$f1} pair. The set of call-saved registers also
+remains the same, but all 64 bits are saved.
-The resulting code should be considerably faster in majority of cases and avoid
-the numerical instability problems of 387 code, but may break some existing
-code that expects temporaries to be 80bit.
+@item -mabicalls
+@itemx -mno-abicalls
+@opindex mabicalls
+@opindex mno-abicalls
+Generate (do not generate) code that is suitable for SVR4-style
+dynamic objects. @option{-mabicalls} is the default for SVR4-based
+systems.
-This is the default choice for x86-64 compiler.
+@item -mshared
+@itemx -mno-shared
+Generate (do not generate) code that is fully position-independent,
+and that can therefore be linked into shared libraries. This option
+only affects @option{-mabicalls}.
+
+All @option{-mabicalls} code has traditionally been position-independent,
+regardless of options like @option{-fPIC} and @option{-fpic}. However,
+as an extension, the GNU toolchain allows executables to use absolute
+accesses for locally-binding symbols. It can also use shorter GP
+initialization sequences and generate direct calls to locally-defined
+functions. This mode is selected by @option{-mno-shared}.
+
+@option{-mno-shared} depends on binutils 2.16 or higher and generates
+objects that can only be linked by the GNU linker. However, the option
+does not affect the ABI of the final executable; it only affects the ABI
+of relocatable objects. Using @option{-mno-shared} will generally make
+executables both smaller and quicker.
+
+@option{-mshared} is the default.
+
+@item -mplt
+@itemx -mno-plt
+@opindex mplt
+@opindex mno-plt
+Assume (do not assume) that the static and dynamic linkers
+support PLTs and copy relocations. This option only affects
+@samp{-mno-shared -mabicalls}. For the n64 ABI, this option
+has no effect without @samp{-msym32}.
+
+You can make @option{-mplt} the default by configuring
+GCC with @option{--with-mips-plt}. The default is
+@option{-mno-plt} otherwise.
+
+@item -mxgot
+@itemx -mno-xgot
+@opindex mxgot
+@opindex mno-xgot
+Lift (do not lift) the usual restrictions on the size of the global
+offset table.
+
+GCC normally uses a single instruction to load values from the GOT@.
+While this is relatively efficient, it will only work if the GOT
+is smaller than about 64k. Anything larger will cause the linker
+to report an error such as:
+
+@cindex relocation truncated to fit (MIPS)
+@smallexample
+relocation truncated to fit: R_MIPS_GOT16 foobar
+@end smallexample
-@item sse,387
-Attempt to utilize both instruction sets at once. This effectivly double the
-amount of available registers and on chips with separate execution units for
-387 and SSE the execution resources too. Use this option with care, as it is
-still experimental, because gcc register allocator does not model separate
-functional units well resulting in instable performance.
-@end table
+If this happens, you should recompile your code with @option{-mxgot}.
+It should then work with very large GOTs, although it will also be
+less efficient, since it will take three instructions to fetch the
+value of a global symbol.
-@item -masm=@var{dialect}
-@opindex masm=@var{dialect}
-Output asm instructions using selected @var{dialect}. Supported choices are
-@samp{intel} or @samp{att} (the default one).
+Note that some linkers can create multiple GOTs. If you have such a
+linker, you should only need to use @option{-mxgot} when a single object
+file accesses more than 64k's worth of GOT entries. Very few do.
-@item -mieee-fp
-@itemx -mno-ieee-fp
-@opindex mieee-fp
-@opindex mno-ieee-fp
-Control whether or not the compiler uses IEEE floating point
-comparisons. These handle correctly the case where the result of a
-comparison is unordered.
+These options have no effect unless GCC is generating position
+independent code.
+
+@item -mgp32
+@opindex mgp32
+Assume that general-purpose registers are 32 bits wide.
+
+@item -mgp64
+@opindex mgp64
+Assume that general-purpose registers are 64 bits wide.
+
+@item -mfp32
+@opindex mfp32
+Assume that floating-point registers are 32 bits wide.
+
+@item -mfp64
+@opindex mfp64
+Assume that floating-point registers are 64 bits wide.
+
+@item -mhard-float
+@opindex mhard-float
+Use floating-point coprocessor instructions.
@item -msoft-float
@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not part of GCC@.
-Normally the facilities of the machine's usual C compiler are used, but
-this can't be done directly in cross-compilation. You must make your
-own arrangements to provide suitable library functions for
-cross-compilation.
+Do not use floating-point coprocessor instructions. Implement
+floating-point calculations using library calls instead.
-On machines where a function returns floating point results in the 80387
-register stack, some floating point opcodes may be emitted even if
-@option{-msoft-float} is used.
+@item -msingle-float
+@opindex msingle-float
+Assume that the floating-point coprocessor only supports single-precision
+operations.
-@item -mno-fp-ret-in-387
-@opindex mno-fp-ret-in-387
-Do not use the FPU registers for return values of functions.
+@item -mdouble-float
+@opindex mdouble-float
+Assume that the floating-point coprocessor supports double-precision
+operations. This is the default.
-The usual calling convention has functions return values of types
-@code{float} and @code{double} in an FPU register, even if there
-is no FPU@. The idea is that the operating system should emulate
-an FPU@.
+@item -mllsc
+@itemx -mno-llsc
+@opindex mllsc
+@opindex mno-llsc
+Use (do not use) @samp{ll}, @samp{sc}, and @samp{sync} instructions to
+implement atomic memory built-in functions. When neither option is
+specified, GCC will use the instructions if the target architecture
+supports them.
+
+@option{-mllsc} is useful if the runtime environment can emulate the
+instructions and @option{-mno-llsc} can be useful when compiling for
+nonstandard ISAs. You can make either option the default by
+configuring GCC with @option{--with-llsc} and @option{--without-llsc}
+respectively. @option{--with-llsc} is the default for some
+configurations; see the installation documentation for details.
+
+@item -mdsp
+@itemx -mno-dsp
+@opindex mdsp
+@opindex mno-dsp
+Use (do not use) revision 1 of the MIPS DSP ASE@.
+@xref{MIPS DSP Built-in Functions}. This option defines the
+preprocessor macro @samp{__mips_dsp}. It also defines
+@samp{__mips_dsp_rev} to 1.
+
+@item -mdspr2
+@itemx -mno-dspr2
+@opindex mdspr2
+@opindex mno-dspr2
+Use (do not use) revision 2 of the MIPS DSP ASE@.
+@xref{MIPS DSP Built-in Functions}. This option defines the
+preprocessor macros @samp{__mips_dsp} and @samp{__mips_dspr2}.
+It also defines @samp{__mips_dsp_rev} to 2.
+
+@item -msmartmips
+@itemx -mno-smartmips
+@opindex msmartmips
+@opindex mno-smartmips
+Use (do not use) the MIPS SmartMIPS ASE.
+
+@item -mpaired-single
+@itemx -mno-paired-single
+@opindex mpaired-single
+@opindex mno-paired-single
+Use (do not use) paired-single floating-point instructions.
+@xref{MIPS Paired-Single Support}. This option requires
+hardware floating-point support to be enabled.
+
+@item -mdmx
+@itemx -mno-mdmx
+@opindex mdmx
+@opindex mno-mdmx
+Use (do not use) MIPS Digital Media Extension instructions.
+This option can only be used when generating 64-bit code and requires
+hardware floating-point support to be enabled.
+
+@item -mips3d
+@itemx -mno-mips3d
+@opindex mips3d
+@opindex mno-mips3d
+Use (do not use) the MIPS-3D ASE@. @xref{MIPS-3D Built-in Functions}.
+The option @option{-mips3d} implies @option{-mpaired-single}.
+
+@item -mmt
+@itemx -mno-mt
+@opindex mmt
+@opindex mno-mt
+Use (do not use) MT Multithreading instructions.
-The option @option{-mno-fp-ret-in-387} causes such values to be returned
-in ordinary CPU registers instead.
+@item -mlong64
+@opindex mlong64
+Force @code{long} types to be 64 bits wide. See @option{-mlong32} for
+an explanation of the default and the way that the pointer size is
+determined.
-@item -mno-fancy-math-387
-@opindex mno-fancy-math-387
-Some 387 emulators do not support the @code{sin}, @code{cos} and
-@code{sqrt} instructions for the 387. Specify this option to avoid
-generating those instructions. This option is the default on FreeBSD,
-OpenBSD and NetBSD@. This option is overridden when @option{-march}
-indicates that the target cpu will always have an FPU and so the
-instruction will not need emulation. As of revision 2.6.1, these
-instructions are not generated unless you also use the
-@option{-funsafe-math-optimizations} switch.
+@item -mlong32
+@opindex mlong32
+Force @code{long}, @code{int}, and pointer types to be 32 bits wide.
+
+The default size of @code{int}s, @code{long}s and pointers depends on
+the ABI@. All the supported ABIs use 32-bit @code{int}s. The n64 ABI
+uses 64-bit @code{long}s, as does the 64-bit EABI; the others use
+32-bit @code{long}s. Pointers are the same size as @code{long}s,
+or the same size as integer registers, whichever is smaller.
+
+@item -msym32
+@itemx -mno-sym32
+@opindex msym32
+@opindex mno-sym32
+Assume (do not assume) that all symbols have 32-bit values, regardless
+of the selected ABI@. This option is useful in combination with
+@option{-mabi=64} and @option{-mno-abicalls} because it allows GCC
+to generate shorter and faster references to symbolic addresses.
-@item -malign-double
-@itemx -mno-align-double
-@opindex malign-double
-@opindex mno-align-double
-Control whether GCC aligns @code{double}, @code{long double}, and
-@code{long long} variables on a two word boundary or a one word
-boundary. Aligning @code{double} variables on a two word boundary will
-produce code that runs somewhat faster on a @samp{Pentium} at the
-expense of more memory.
+@item -G @var{num}
+@opindex G
+Put definitions of externally-visible data in a small data section
+if that data is no bigger than @var{num} bytes. GCC can then access
+the data more efficiently; see @option{-mgpopt} for details.
+
+The default @option{-G} option depends on the configuration.
+
+@item -mlocal-sdata
+@itemx -mno-local-sdata
+@opindex mlocal-sdata
+@opindex mno-local-sdata
+Extend (do not extend) the @option{-G} behavior to local data too,
+such as to static variables in C@. @option{-mlocal-sdata} is the
+default for all configurations.
+
+If the linker complains that an application is using too much small data,
+you might want to try rebuilding the less performance-critical parts with
+@option{-mno-local-sdata}. You might also want to build large
+libraries with @option{-mno-local-sdata}, so that the libraries leave
+more room for the main program.
+
+@item -mextern-sdata
+@itemx -mno-extern-sdata
+@opindex mextern-sdata
+@opindex mno-extern-sdata
+Assume (do not assume) that externally-defined data will be in
+a small data section if that data is within the @option{-G} limit.
+@option{-mextern-sdata} is the default for all configurations.
+
+If you compile a module @var{Mod} with @option{-mextern-sdata} @option{-G
+@var{num}} @option{-mgpopt}, and @var{Mod} references a variable @var{Var}
+that is no bigger than @var{num} bytes, you must make sure that @var{Var}
+is placed in a small data section. If @var{Var} is defined by another
+module, you must either compile that module with a high-enough
+@option{-G} setting or attach a @code{section} attribute to @var{Var}'s
+definition. If @var{Var} is common, you must link the application
+with a high-enough @option{-G} setting.
+
+The easiest way of satisfying these restrictions is to compile
+and link every module with the same @option{-G} option. However,
+you may wish to build a library that supports several different
+small data limits. You can do this by compiling the library with
+the highest supported @option{-G} setting and additionally using
+@option{-mno-extern-sdata} to stop the library from making assumptions
+about externally-defined data.
-@strong{Warning:} if you use the @option{-malign-double} switch,
-structures containing the above types will be aligned differently than
-the published application binary interface specifications for the 386
-and will not be binary compatible with structures in code compiled
-without that switch.
+@item -mgpopt
+@itemx -mno-gpopt
+@opindex mgpopt
+@opindex mno-gpopt
+Use (do not use) GP-relative accesses for symbols that are known to be
+in a small data section; see @option{-G}, @option{-mlocal-sdata} and
+@option{-mextern-sdata}. @option{-mgpopt} is the default for all
+configurations.
-@item -m128bit-long-double
-@opindex m128bit-long-double
-Control the size of @code{long double} type. i386 application binary interface
-specify the size to be 12 bytes, while modern architectures (Pentium and newer)
-prefer @code{long double} aligned to 8 or 16 byte boundary. This is
-impossible to reach with 12 byte long doubles in the array accesses.
+@option{-mno-gpopt} is useful for cases where the @code{$gp} register
+might not hold the value of @code{_gp}. For example, if the code is
+part of a library that might be used in a boot monitor, programs that
+call boot monitor routines will pass an unknown value in @code{$gp}.
+(In such situations, the boot monitor itself would usually be compiled
+with @option{-G0}.)
-@strong{Warning:} if you use the @option{-m128bit-long-double} switch, the
-structures and arrays containing @code{long double} will change their size as
-well as function calling convention for function taking @code{long double}
-will be modified.
+@option{-mno-gpopt} implies @option{-mno-local-sdata} and
+@option{-mno-extern-sdata}.
-@item -m96bit-long-double
-@opindex m96bit-long-double
-Set the size of @code{long double} to 96 bits as required by the i386
-application binary interface. This is the default.
+@item -membedded-data
+@itemx -mno-embedded-data
+@opindex membedded-data
+@opindex mno-embedded-data
+Allocate variables to the read-only data section first if possible, then
+next in the small data section if possible, otherwise in data. This gives
+slightly slower code than the default, but reduces the amount of RAM required
+when executing, and thus may be preferred for some embedded systems.
-@item -msvr3-shlib
-@itemx -mno-svr3-shlib
-@opindex msvr3-shlib
-@opindex mno-svr3-shlib
-Control whether GCC places uninitialized local variables into the
-@code{bss} or @code{data} segments. @option{-msvr3-shlib} places them
-into @code{bss}. These options are meaningful only on System V Release 3.
+@item -muninit-const-in-rodata
+@itemx -mno-uninit-const-in-rodata
+@opindex muninit-const-in-rodata
+@opindex mno-uninit-const-in-rodata
+Put uninitialized @code{const} variables in the read-only data section.
+This option is only meaningful in conjunction with @option{-membedded-data}.
-@item -mrtd
-@opindex mrtd
-Use a different function-calling convention, in which functions that
-take a fixed number of arguments return with the @code{ret} @var{num}
-instruction, which pops their arguments while returning. This saves one
-instruction in the caller since there is no need to pop the arguments
-there.
+@item -mcode-readable=@var{setting}
+@opindex mcode-readable
+Specify whether GCC may generate code that reads from executable sections.
+There are three possible settings:
-You can specify that an individual function is called with this calling
-sequence with the function attribute @samp{stdcall}. You can also
-override the @option{-mrtd} option by using the function attribute
-@samp{cdecl}. @xref{Function Attributes}.
+@table @gcctabopt
+@item -mcode-readable=yes
+Instructions may freely access executable sections. This is the
+default setting.
+
+@item -mcode-readable=pcrel
+MIPS16 PC-relative load instructions can access executable sections,
+but other instructions must not do so. This option is useful on 4KSc
+and 4KSd processors when the code TLBs have the Read Inhibit bit set.
+It is also useful on processors that can be configured to have a dual
+instruction/data SRAM interface and that, like the M4K, automatically
+redirect PC-relative loads to the instruction RAM.
+
+@item -mcode-readable=no
+Instructions must not access executable sections. This option can be
+useful on targets that are configured to have a dual instruction/data
+SRAM interface but that (unlike the M4K) do not automatically redirect
+PC-relative loads to the instruction RAM.
+@end table
-@strong{Warning:} this calling convention is incompatible with the one
-normally used on Unix, so you cannot use it if you need to call
-libraries compiled with the Unix compiler.
+@item -msplit-addresses
+@itemx -mno-split-addresses
+@opindex msplit-addresses
+@opindex mno-split-addresses
+Enable (disable) use of the @code{%hi()} and @code{%lo()} assembler
+relocation operators. This option has been superseded by
+@option{-mexplicit-relocs} but is retained for backwards compatibility.
+
+@item -mexplicit-relocs
+@itemx -mno-explicit-relocs
+@opindex mexplicit-relocs
+@opindex mno-explicit-relocs
+Use (do not use) assembler relocation operators when dealing with symbolic
+addresses. The alternative, selected by @option{-mno-explicit-relocs},
+is to use assembler macros instead.
+
+@option{-mexplicit-relocs} is the default if GCC was configured
+to use an assembler that supports relocation operators.
+
+@item -mcheck-zero-division
+@itemx -mno-check-zero-division
+@opindex mcheck-zero-division
+@opindex mno-check-zero-division
+Trap (do not trap) on integer division by zero.
+
+The default is @option{-mcheck-zero-division}.
+
+@item -mdivide-traps
+@itemx -mdivide-breaks
+@opindex mdivide-traps
+@opindex mdivide-breaks
+MIPS systems check for division by zero by generating either a
+conditional trap or a break instruction. Using traps results in
+smaller code, but is only supported on MIPS II and later. Also, some
+versions of the Linux kernel have a bug that prevents trap from
+generating the proper signal (@code{SIGFPE}). Use @option{-mdivide-traps} to
+allow conditional traps on architectures that support them and
+@option{-mdivide-breaks} to force the use of breaks.
+
+The default is usually @option{-mdivide-traps}, but this can be
+overridden at configure time using @option{--with-divide=breaks}.
+Divide-by-zero checks can be completely disabled using
+@option{-mno-check-zero-division}.
+
+@item -mmemcpy
+@itemx -mno-memcpy
+@opindex mmemcpy
+@opindex mno-memcpy
+Force (do not force) the use of @code{memcpy()} for non-trivial block
+moves. The default is @option{-mno-memcpy}, which allows GCC to inline
+most constant-sized copies.
+
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Disable (do not disable) use of the @code{jal} instruction. Calling
+functions using @code{jal} is more efficient but requires the caller
+and callee to be in the same 256 megabyte segment.
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including @code{printf});
-otherwise incorrect code will be generated for calls to those
-functions.
+This option has no effect on abicalls code. The default is
+@option{-mno-long-calls}.
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
+@item -mmad
+@itemx -mno-mad
+@opindex mmad
+@opindex mno-mad
+Enable (disable) use of the @code{mad}, @code{madu} and @code{mul}
+instructions, as provided by the R4650 ISA@.
-@item -mregparm=@var{num}
-@opindex mregparm
-Control how many registers are used to pass integer arguments. By
-default, no registers are used to pass arguments, and at most 3
-registers can be used. You can control this behavior for a specific
-function by using the function attribute @samp{regparm}.
-@xref{Function Attributes}.
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Enable (disable) use of the floating point multiply-accumulate
+instructions, when they are available. The default is
+@option{-mfused-madd}.
-@strong{Warning:} if you use this switch, and
-@var{num} is nonzero, then you must build all modules with the same
-value, including any libraries. This includes the system libraries and
-startup modules.
+When multiply-accumulate instructions are used, the intermediate
+product is calculated to infinite precision and is not subject to
+the FCSR Flush to Zero bit. This may be undesirable in some
+circumstances.
-@item -mpreferred-stack-boundary=@var{num}
-@opindex mpreferred-stack-boundary
-Attempt to keep the stack boundary aligned to a 2 raised to @var{num}
-byte boundary. If @option{-mpreferred-stack-boundary} is not specified,
-the default is 4 (16 bytes or 128 bits), except when optimizing for code
-size (@option{-Os}), in which case the default is the minimum correct
-alignment (4 bytes for x86, and 8 bytes for x86-64).
+@item -nocpp
+@opindex nocpp
+Tell the MIPS assembler to not run its preprocessor over user
+assembler files (with a @samp{.s} suffix) when assembling them.
-On Pentium and PentiumPro, @code{double} and @code{long double} values
-should be aligned to an 8 byte boundary (see @option{-malign-double}) or
-suffer significant run time performance penalties. On Pentium III, the
-Streaming SIMD Extension (SSE) data type @code{__m128} suffers similar
-penalties if it is not 16 byte aligned.
+@item -mfix-r4000
+@itemx -mno-fix-r4000
+@opindex mfix-r4000
+@opindex mno-fix-r4000
+Work around certain R4000 CPU errata:
+@itemize @minus
+@item
+A double-word or a variable shift may give an incorrect result if executed
+immediately after starting an integer division.
+@item
+A double-word or a variable shift may give an incorrect result if executed
+while an integer multiplication is in progress.
+@item
+An integer division may give an incorrect result if started in a delay slot
+of a taken branch or a jump.
+@end itemize
-To ensure proper alignment of this values on the stack, the stack boundary
-must be as aligned as that required by any value stored on the stack.
-Further, every function must be generated such that it keeps the stack
-aligned. Thus calling a function compiled with a higher preferred
-stack boundary from a function compiled with a lower preferred stack
-boundary will most likely misalign the stack. It is recommended that
-libraries that use callbacks always use the default setting.
+@item -mfix-r4400
+@itemx -mno-fix-r4400
+@opindex mfix-r4400
+@opindex mno-fix-r4400
+Work around certain R4400 CPU errata:
+@itemize @minus
+@item
+A double-word or a variable shift may give an incorrect result if executed
+immediately after starting an integer division.
+@end itemize
-This extra alignment does consume extra stack space, and generally
-increases code size. Code that is sensitive to stack space usage, such
-as embedded systems and operating system kernels, may want to reduce the
-preferred alignment to @option{-mpreferred-stack-boundary=2}.
+@item -mfix-r10000
+@itemx -mno-fix-r10000
+@opindex mfix-r10000
+@opindex mno-fix-r10000
+Work around certain R10000 errata:
+@itemize @minus
+@item
+@code{ll}/@code{sc} sequences may not behave atomically on revisions
+prior to 3.0. They may deadlock on revisions 2.6 and earlier.
+@end itemize
-@item -mmmx
-@itemx -mno-mmx
-@item -msse
-@itemx -mno-sse
-@item -msse2
-@itemx -mno-sse2
-@item -m3dnow
-@itemx -mno-3dnow
-@opindex mmmx
-@opindex mno-mmx
-@opindex msse
-@opindex mno-sse
-@opindex m3dnow
-@opindex mno-3dnow
-These switches enable or disable the use of built-in functions that allow
-direct access to the MMX, SSE and 3Dnow extensions of the instruction set.
+This option can only be used if the target architecture supports
+branch-likely instructions. @option{-mfix-r10000} is the default when
+@option{-march=r10000} is used; @option{-mno-fix-r10000} is the default
+otherwise.
-@xref{X86 Built-in Functions}, for details of the functions enabled
-and disabled by these switches.
+@item -mfix-vr4120
+@itemx -mno-fix-vr4120
+@opindex mfix-vr4120
+Work around certain VR4120 errata:
+@itemize @minus
+@item
+@code{dmultu} does not always produce the correct result.
+@item
+@code{div} and @code{ddiv} do not always produce the correct result if one
+of the operands is negative.
+@end itemize
+The workarounds for the division errata rely on special functions in
+@file{libgcc.a}. At present, these functions are only provided by
+the @code{mips64vr*-elf} configurations.
+
+Other VR4120 errata require a nop to be inserted between certain pairs of
+instructions. These errata are handled by the assembler, not by GCC itself.
+
+@item -mfix-vr4130
+@opindex mfix-vr4130
+Work around the VR4130 @code{mflo}/@code{mfhi} errata. The
+workarounds are implemented by the assembler rather than by GCC,
+although GCC will avoid using @code{mflo} and @code{mfhi} if the
+VR4130 @code{macc}, @code{macchi}, @code{dmacc} and @code{dmacchi}
+instructions are available instead.
+
+@item -mfix-sb1
+@itemx -mno-fix-sb1
+@opindex mfix-sb1
+Work around certain SB-1 CPU core errata.
+(This flag currently works around the SB-1 revision 2
+``F1'' and ``F2'' floating point errata.)
+
+@item -mr10k-cache-barrier=@var{setting}
+@opindex mr10k-cache-barrier
+Specify whether GCC should insert cache barriers to avoid the
+side-effects of speculation on R10K processors.
+
+In common with many processors, the R10K tries to predict the outcome
+of a conditional branch and speculatively executes instructions from
+the ``taken'' branch. It later aborts these instructions if the
+predicted outcome was wrong. However, on the R10K, even aborted
+instructions can have side effects.
+
+This problem only affects kernel stores and, depending on the system,
+kernel loads. As an example, a speculatively-executed store may load
+the target memory into cache and mark the cache line as dirty, even if
+the store itself is later aborted. If a DMA operation writes to the
+same area of memory before the ``dirty'' line is flushed, the cached
+data will overwrite the DMA-ed data. See the R10K processor manual
+for a full description, including other potential problems.
+
+One workaround is to insert cache barrier instructions before every memory
+access that might be speculatively executed and that might have side
+effects even if aborted. @option{-mr10k-cache-barrier=@var{setting}}
+controls GCC's implementation of this workaround. It assumes that
+aborted accesses to any byte in the following regions will not have
+side effects:
-To have SSE/SSE2 instructions generated automatically from floating-point code,
-see @option{-mfpmath=sse}.
+@enumerate
+@item
+the memory occupied by the current function's stack frame;
-@item -mpush-args
-@itemx -mno-push-args
-@opindex mpush-args
-@opindex mno-push-args
-Use PUSH operations to store outgoing parameters. This method is shorter
-and usually equally fast as method using SUB/MOV operations and is enabled
-by default. In some cases disabling it may improve performance because of
-improved scheduling and reduced dependencies.
+@item
+the memory occupied by an incoming stack argument;
-@item -maccumulate-outgoing-args
-@opindex maccumulate-outgoing-args
-If enabled, the maximum amount of space required for outgoing arguments will be
-computed in the function prologue. This is faster on most modern CPUs
-because of reduced dependencies, improved scheduling and reduced stack usage
-when preferred stack boundary is not equal to 2. The drawback is a notable
-increase in code size. This switch implies @option{-mno-push-args}.
+@item
+the memory occupied by an object with a link-time-constant address.
+@end enumerate
-@item -mthreads
-@opindex mthreads
-Support thread-safe exception handling on @samp{Mingw32}. Code that relies
-on thread-safe exception handling must compile and link all code with the
-@option{-mthreads} option. When compiling, @option{-mthreads} defines
-@option{-D_MT}; when linking, it links in a special thread helper library
-@option{-lmingwthrd} which cleans up per thread exception handling data.
+It is the kernel's responsibility to ensure that speculative
+accesses to these regions are indeed safe.
-@item -mno-align-stringops
-@opindex mno-align-stringops
-Do not align destination of inlined string operations. This switch reduces
-code size and improves performance in case the destination is already aligned,
-but gcc don't know about it.
+If the input program contains a function declaration such as:
-@item -minline-all-stringops
-@opindex minline-all-stringops
-By default GCC inlines string operations only when destination is known to be
-aligned at least to 4 byte boundary. This enables more inlining, increase code
-size, but may improve performance of code that depends on fast memcpy, strlen
-and memset for short lengths.
+@smallexample
+void foo (void);
+@end smallexample
-@item -momit-leaf-frame-pointer
-@opindex momit-leaf-frame-pointer
-Don't keep the frame pointer in a register for leaf functions. This
-avoids the instructions to save, set up and restore frame pointers and
-makes an extra register available in leaf functions. The option
-@option{-fomit-frame-pointer} removes the frame pointer for all functions
-which might make debugging harder.
-@end table
+then the implementation of @code{foo} must allow @code{j foo} and
+@code{jal foo} to be executed speculatively. GCC honors this
+restriction for functions it compiles itself. It expects non-GCC
+functions (such as hand-written assembly code) to do the same.
-These @samp{-m} switches are supported in addition to the above
-on AMD x86-64 processors in 64-bit environments.
+The option has three forms:
@table @gcctabopt
-@item -m32
-@itemx -m64
-@opindex m32
-@opindex m64
-Generate code for a 32-bit or 64-bit environment.
-The 32-bit environment sets int, long and pointer to 32 bits and
-generates code that runs on any i386 system.
-The 64-bit environment sets int to 32 bits and long and pointer
-to 64 bits and generates code for AMD's x86-64 architecture.
+@item -mr10k-cache-barrier=load-store
+Insert a cache barrier before a load or store that might be
+speculatively executed and that might have side effects even
+if aborted.
-@item -mno-red-zone
-@opindex no-red-zone
-Do not use a so called red zone for x86-64 code. The red zone is mandated
-by the x86-64 ABI, it is a 128-byte area beyond the location of the
-stack pointer that will not be modified by signal or interrupt handlers
-and therefore can be used for temporary data without adjusting the stack
-pointer. The flag @option{-mno-red-zone} disables this red zone.
-
-@item -mcmodel=small
-@opindex mcmodel=small
-Generate code for the small code model: the program and its symbols must
-be linked in the lower 2 GB of the address space. Pointers are 64 bits.
-Programs can be statically or dynamically linked. This is the default
-code model.
+@item -mr10k-cache-barrier=store
+Insert a cache barrier before a store that might be speculatively
+executed and that might have side effects even if aborted.
-@item -mcmodel=kernel
-@opindex mcmodel=kernel
-Generate code for the kernel code model. The kernel runs in the
-negative 2 GB of the address space.
-This model has to be used for Linux kernel code.
+@item -mr10k-cache-barrier=none
+Disable the insertion of cache barriers. This is the default setting.
+@end table
-@item -mcmodel=medium
-@opindex mcmodel=medium
-Generate code for the medium model: The program is linked in the lower 2
-GB of the address space but symbols can be located anywhere in the
-address space. Programs can be statically or dynamically linked, but
-building of shared libraries are not supported with the medium model.
+@item -mflush-func=@var{func}
+@itemx -mno-flush-func
+@opindex mflush-func
+Specifies the function to call to flush the I and D caches, or to not
+call any such function. If called, the function must take the same
+arguments as the common @code{_flush_func()}, that is, the address of the
+memory range for which the cache is being flushed, the size of the
+memory range, and the number 3 (to flush both caches). The default
+depends on the target GCC was configured for, but commonly is either
+@samp{_flush_func} or @samp{__cpu_flush}.
-@item -mcmodel=large
-@opindex mcmodel=large
-Generate code for the large model: This model makes no assumptions
-about addresses and sizes of sections. Currently GCC does not implement
-this model.
+@item mbranch-cost=@var{num}
+@opindex mbranch-cost
+Set the cost of branches to roughly @var{num} ``simple'' instructions.
+This cost is only a heuristic and is not guaranteed to produce
+consistent results across releases. A zero cost redundantly selects
+the default, which is based on the @option{-mtune} setting.
+
+@item -mbranch-likely
+@itemx -mno-branch-likely
+@opindex mbranch-likely
+@opindex mno-branch-likely
+Enable or disable use of Branch Likely instructions, regardless of the
+default for the selected architecture. By default, Branch Likely
+instructions may be generated if they are supported by the selected
+architecture. An exception is for the MIPS32 and MIPS64 architectures
+and processors which implement those architectures; for those, Branch
+Likely instructions will not be generated by default because the MIPS32
+and MIPS64 architectures specifically deprecate their use.
+
+@item -mfp-exceptions
+@itemx -mno-fp-exceptions
+@opindex mfp-exceptions
+Specifies whether FP exceptions are enabled. This affects how we schedule
+FP instructions for some processors. The default is that FP exceptions are
+enabled.
+
+For instance, on the SB-1, if FP exceptions are disabled, and we are emitting
+64-bit code, then we can use both FP pipes. Otherwise, we can only use one
+FP pipe.
+
+@item -mvr4130-align
+@itemx -mno-vr4130-align
+@opindex mvr4130-align
+The VR4130 pipeline is two-way superscalar, but can only issue two
+instructions together if the first one is 8-byte aligned. When this
+option is enabled, GCC will align pairs of instructions that it
+thinks should execute in parallel.
+
+This option only has an effect when optimizing for the VR4130.
+It normally makes code faster, but at the expense of making it bigger.
+It is enabled by default at optimization level @option{-O3}.
@end table
-@node HPPA Options
-@subsection HPPA Options
-@cindex HPPA Options
+@node MMIX Options
+@subsection MMIX Options
+@cindex MMIX Options
-These @samp{-m} options are defined for the HPPA family of computers:
+These options are defined for the MMIX:
@table @gcctabopt
-@item -march=@var{architecture-type}
-@opindex march
-Generate code for the specified architecture. The choices for
-@var{architecture-type} are @samp{1.0} for PA 1.0, @samp{1.1} for PA
-1.1, and @samp{2.0} for PA 2.0 processors. Refer to
-@file{/usr/lib/sched.models} on an HP-UX system to determine the proper
-architecture option for your machine. Code compiled for lower numbered
-architectures will run on higher numbered architectures, but not the
-other way around.
+@item -mlibfuncs
+@itemx -mno-libfuncs
+@opindex mlibfuncs
+@opindex mno-libfuncs
+Specify that intrinsic library functions are being compiled, passing all
+values in registers, no matter the size.
-PA 2.0 support currently requires gas snapshot 19990413 or later. The
-next release of binutils (current is 2.9.1) will probably contain PA 2.0
-support.
+@item -mepsilon
+@itemx -mno-epsilon
+@opindex mepsilon
+@opindex mno-epsilon
+Generate floating-point comparison instructions that compare with respect
+to the @code{rE} epsilon register.
-@item -mpa-risc-1-0
-@itemx -mpa-risc-1-1
-@itemx -mpa-risc-2-0
-@opindex mpa-risc-1-0
-@opindex mpa-risc-1-1
-@opindex mpa-risc-2-0
-Synonyms for @option{-march=1.0}, @option{-march=1.1}, and @option{-march=2.0} respectively.
+@item -mabi=mmixware
+@itemx -mabi=gnu
+@opindex mabi-mmixware
+@opindex mabi=gnu
+Generate code that passes function parameters and return values that (in
+the called function) are seen as registers @code{$0} and up, as opposed to
+the GNU ABI which uses global registers @code{$231} and up.
-@item -mbig-switch
-@opindex mbig-switch
-Generate code suitable for big switch tables. Use this option only if
-the assembler/linker complain about out of range branches within a switch
-table.
+@item -mzero-extend
+@itemx -mno-zero-extend
+@opindex mzero-extend
+@opindex mno-zero-extend
+When reading data from memory in sizes shorter than 64 bits, use (do not
+use) zero-extending load instructions by default, rather than
+sign-extending ones.
-@item -mjump-in-delay
-@opindex mjump-in-delay
-Fill delay slots of function calls with unconditional jump instructions
-by modifying the return pointer for the function call to be the target
-of the conditional jump.
+@item -mknuthdiv
+@itemx -mno-knuthdiv
+@opindex mknuthdiv
+@opindex mno-knuthdiv
+Make the result of a division yielding a remainder have the same sign as
+the divisor. With the default, @option{-mno-knuthdiv}, the sign of the
+remainder follows the sign of the dividend. Both methods are
+arithmetically valid, the latter being almost exclusively used.
-@item -mdisable-fpregs
-@opindex mdisable-fpregs
-Prevent floating point registers from being used in any manner. This is
-necessary for compiling kernels which perform lazy context switching of
-floating point registers. If you use this option and attempt to perform
-floating point operations, the compiler will abort.
+@item -mtoplevel-symbols
+@itemx -mno-toplevel-symbols
+@opindex mtoplevel-symbols
+@opindex mno-toplevel-symbols
+Prepend (do not prepend) a @samp{:} to all global symbols, so the assembly
+code can be used with the @code{PREFIX} assembly directive.
+
+@item -melf
+@opindex melf
+Generate an executable in the ELF format, rather than the default
+@samp{mmo} format used by the @command{mmix} simulator.
+
+@item -mbranch-predict
+@itemx -mno-branch-predict
+@opindex mbranch-predict
+@opindex mno-branch-predict
+Use (do not use) the probable-branch instructions, when static branch
+prediction indicates a probable branch.
-@item -mdisable-indexing
-@opindex mdisable-indexing
-Prevent the compiler from using indexing address modes. This avoids some
-rather obscure problems when compiling MIG generated code under MACH@.
+@item -mbase-addresses
+@itemx -mno-base-addresses
+@opindex mbase-addresses
+@opindex mno-base-addresses
+Generate (do not generate) code that uses @emph{base addresses}. Using a
+base address automatically generates a request (handled by the assembler
+and the linker) for a constant to be set up in a global register. The
+register is used for one or more base address requests within the range 0
+to 255 from the value held in the register. The generally leads to short
+and fast code, but the number of different data items that can be
+addressed is limited. This means that a program that uses lots of static
+data may require @option{-mno-base-addresses}.
-@item -mno-space-regs
-@opindex mno-space-regs
-Generate code that assumes the target has no space registers. This allows
-GCC to generate faster indirect calls and use unscaled index address modes.
+@item -msingle-exit
+@itemx -mno-single-exit
+@opindex msingle-exit
+@opindex mno-single-exit
+Force (do not force) generated code to have a single exit point in each
+function.
+@end table
-Such code is suitable for level 0 PA systems and kernels.
+@node MN10300 Options
+@subsection MN10300 Options
+@cindex MN10300 options
-@item -mfast-indirect-calls
-@opindex mfast-indirect-calls
-Generate code that assumes calls never cross space boundaries. This
-allows GCC to emit code which performs faster indirect calls.
+These @option{-m} options are defined for Matsushita MN10300 architectures:
-This option will not work in the presence of shared libraries or nested
-functions.
+@table @gcctabopt
+@item -mmult-bug
+@opindex mmult-bug
+Generate code to avoid bugs in the multiply instructions for the MN10300
+processors. This is the default.
-@item -mlong-load-store
-@opindex mlong-load-store
-Generate 3-instruction load and store sequences as sometimes required by
-the HP-UX 10 linker. This is equivalent to the @samp{+k} option to
-the HP compilers.
+@item -mno-mult-bug
+@opindex mno-mult-bug
+Do not generate code to avoid bugs in the multiply instructions for the
+MN10300 processors.
-@item -mportable-runtime
-@opindex mportable-runtime
-Use the portable calling conventions proposed by HP for ELF systems.
+@item -mam33
+@opindex mam33
+Generate code which uses features specific to the AM33 processor.
-@item -mgas
-@opindex mgas
-Enable the use of assembler directives only GAS understands.
+@item -mno-am33
+@opindex mno-am33
+Do not generate code which uses features specific to the AM33 processor. This
+is the default.
-@item -mschedule=@var{cpu-type}
-@opindex mschedule
-Schedule code according to the constraints for the machine type
-@var{cpu-type}. The choices for @var{cpu-type} are @samp{700}
-@samp{7100}, @samp{7100LC}, @samp{7200}, and @samp{8000}. Refer to
-@file{/usr/lib/sched.models} on an HP-UX system to determine the
-proper scheduling option for your machine.
+@item -mreturn-pointer-on-d0
+@opindex mreturn-pointer-on-d0
+When generating a function which returns a pointer, return the pointer
+in both @code{a0} and @code{d0}. Otherwise, the pointer is returned
+only in a0, and attempts to call such functions without a prototype
+would result in errors. Note that this option is on by default; use
+@option{-mno-return-pointer-on-d0} to disable it.
-@item -mlinker-opt
-@opindex mlinker-opt
-Enable the optimization pass in the HPUX linker. Note this makes symbolic
-debugging impossible. It also triggers a bug in the HPUX 8 and HPUX 9 linkers
-in which they give bogus error messages when linking some programs.
+@item -mno-crt0
+@opindex mno-crt0
+Do not link in the C run-time initialization object file.
-@item -msoft-float
-@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries are not available for all HPPA
-targets. Normally the facilities of the machine's usual C compiler are
-used, but this cannot be done directly in cross-compilation. You must make
-your own arrangements to provide suitable library functions for
-cross-compilation. The embedded target @samp{hppa1.1-*-pro}
-does provide software floating point support.
+@item -mrelax
+@opindex mrelax
+Indicate to the linker that it should perform a relaxation optimization pass
+to shorten branches, calls and absolute memory addresses. This option only
+has an effect when used on the command line for the final link step.
-@option{-msoft-float} changes the calling convention in the output file;
-therefore, it is only useful if you compile @emph{all} of a program with
-this option. In particular, you need to compile @file{libgcc.a}, the
-library that comes with GCC, with @option{-msoft-float} in order for
-this to work.
+This option makes symbolic debugging impossible.
@end table
-@node Intel 960 Options
-@subsection Intel 960 Options
+@node PDP-11 Options
+@subsection PDP-11 Options
+@cindex PDP-11 Options
-These @samp{-m} options are defined for the Intel 960 implementations:
+These options are defined for the PDP-11:
@table @gcctabopt
-@item -m@var{cpu-type}
-@opindex mka
-@opindex mkb
-@opindex mmc
-@opindex mca
-@opindex mcf
-@opindex msa
-@opindex msb
-Assume the defaults for the machine type @var{cpu-type} for some of
-the other options, including instruction scheduling, floating point
-support, and addressing modes. The choices for @var{cpu-type} are
-@samp{ka}, @samp{kb}, @samp{mc}, @samp{ca}, @samp{cf},
-@samp{sa}, and @samp{sb}.
-The default is
-@samp{kb}.
-
-@item -mnumerics
-@itemx -msoft-float
-@opindex mnumerics
-@opindex msoft-float
-The @option{-mnumerics} option indicates that the processor does support
-floating-point instructions. The @option{-msoft-float} option indicates
-that floating-point support should not be assumed.
-
-@item -mleaf-procedures
-@itemx -mno-leaf-procedures
-@opindex mleaf-procedures
-@opindex mno-leaf-procedures
-Do (or do not) attempt to alter leaf procedures to be callable with the
-@code{bal} instruction as well as @code{call}. This will result in more
-efficient code for explicit calls when the @code{bal} instruction can be
-substituted by the assembler or linker, but less efficient code in other
-cases, such as calls via function pointers, or using a linker that doesn't
-support this optimization.
-
-@item -mtail-call
-@itemx -mno-tail-call
-@opindex mtail-call
-@opindex mno-tail-call
-Do (or do not) make additional attempts (beyond those of the
-machine-independent portions of the compiler) to optimize tail-recursive
-calls into branches. You may not want to do this because the detection of
-cases where this is not valid is not totally complete. The default is
-@option{-mno-tail-call}.
-
-@item -mcomplex-addr
-@itemx -mno-complex-addr
-@opindex mcomplex-addr
-@opindex mno-complex-addr
-Assume (or do not assume) that the use of a complex addressing mode is a
-win on this implementation of the i960. Complex addressing modes may not
-be worthwhile on the K-series, but they definitely are on the C-series.
-The default is currently @option{-mcomplex-addr} for all processors except
-the CB and CC@.
-
-@item -mcode-align
-@itemx -mno-code-align
-@opindex mcode-align
-@opindex mno-code-align
-Align code to 8-byte boundaries for faster fetching (or don't bother).
-Currently turned on by default for C-series implementations only.
-
-@ignore
-@item -mclean-linkage
-@itemx -mno-clean-linkage
-@opindex mclean-linkage
-@opindex mno-clean-linkage
-These options are not fully implemented.
-@end ignore
-
-@item -mic-compat
-@itemx -mic2.0-compat
-@itemx -mic3.0-compat
-@opindex mic-compat
-@opindex mic2.0-compat
-@opindex mic3.0-compat
-Enable compatibility with iC960 v2.0 or v3.0.
-
-@item -masm-compat
-@itemx -mintel-asm
-@opindex masm-compat
-@opindex mintel-asm
-Enable compatibility with the iC960 assembler.
-
-@item -mstrict-align
-@itemx -mno-strict-align
-@opindex mstrict-align
-@opindex mno-strict-align
-Do not permit (do permit) unaligned accesses.
-
-@item -mold-align
-@opindex mold-align
-Enable structure-alignment compatibility with Intel's gcc release version
-1.3 (based on gcc 1.37). This option implies @option{-mstrict-align}.
+@item -mfpu
+@opindex mfpu
+Use hardware FPP floating point. This is the default. (FIS floating
+point on the PDP-11/40 is not supported.)
-@item -mlong-double-64
-@opindex mlong-double-64
-Implement type @samp{long double} as 64-bit floating point numbers.
-Without the option @samp{long double} is implemented by 80-bit
-floating point numbers. The only reason we have it because there is
-no 128-bit @samp{long double} support in @samp{fp-bit.c} yet. So it
-is only useful for people using soft-float targets. Otherwise, we
-should recommend against use of it.
+@item -msoft-float
+@opindex msoft-float
+Do not use hardware floating point.
-@end table
+@item -mac0
+@opindex mac0
+Return floating-point results in ac0 (fr0 in Unix assembler syntax).
-@node DEC Alpha Options
-@subsection DEC Alpha Options
+@item -mno-ac0
+@opindex mno-ac0
+Return floating-point results in memory. This is the default.
-These @samp{-m} options are defined for the DEC Alpha implementations:
+@item -m40
+@opindex m40
+Generate code for a PDP-11/40.
-@table @gcctabopt
-@item -mno-soft-float
-@itemx -msoft-float
-@opindex mno-soft-float
-@opindex msoft-float
-Use (do not use) the hardware floating-point instructions for
-floating-point operations. When @option{-msoft-float} is specified,
-functions in @file{libgcc.a} will be used to perform floating-point
-operations. Unless they are replaced by routines that emulate the
-floating-point operations, or compiled in such a way as to call such
-emulations routines, these routines will issue floating-point
-operations. If you are compiling for an Alpha without floating-point
-operations, you must ensure that the library is built so as not to call
-them.
+@item -m45
+@opindex m45
+Generate code for a PDP-11/45. This is the default.
-Note that Alpha implementations without floating-point operations are
-required to have floating-point registers.
+@item -m10
+@opindex m10
+Generate code for a PDP-11/10.
-@item -mfp-reg
-@itemx -mno-fp-regs
-@opindex mfp-reg
-@opindex mno-fp-regs
-Generate code that uses (does not use) the floating-point register set.
-@option{-mno-fp-regs} implies @option{-msoft-float}. If the floating-point
-register set is not used, floating point operands are passed in integer
-registers as if they were integers and floating-point results are passed
-in @code{$0} instead of @code{$f0}. This is a non-standard calling sequence,
-so any function with a floating-point argument or return value called by code
-compiled with @option{-mno-fp-regs} must also be compiled with that
-option.
+@item -mbcopy-builtin
+@opindex bcopy-builtin
+Use inline @code{movmemhi} patterns for copying memory. This is the
+default.
-A typical use of this option is building a kernel that does not use,
-and hence need not save and restore, any floating-point registers.
+@item -mbcopy
+@opindex mbcopy
+Do not use inline @code{movmemhi} patterns for copying memory.
-@item -mieee
-@opindex mieee
-The Alpha architecture implements floating-point hardware optimized for
-maximum performance. It is mostly compliant with the IEEE floating
-point standard. However, for full compliance, software assistance is
-required. This option generates code fully IEEE compliant code
-@emph{except} that the @var{inexact-flag} is not maintained (see below).
-If this option is turned on, the preprocessor macro @code{_IEEE_FP} is
-defined during compilation. The resulting code is less efficient but is
-able to correctly support denormalized numbers and exceptional IEEE
-values such as not-a-number and plus/minus infinity. Other Alpha
-compilers call this option @option{-ieee_with_no_inexact}.
+@item -mint16
+@itemx -mno-int32
+@opindex mint16
+@opindex mno-int32
+Use 16-bit @code{int}. This is the default.
-@item -mieee-with-inexact
-@opindex mieee-with-inexact
-This is like @option{-mieee} except the generated code also maintains
-the IEEE @var{inexact-flag}. Turning on this option causes the
-generated code to implement fully-compliant IEEE math. In addition to
-@code{_IEEE_FP}, @code{_IEEE_FP_EXACT} is defined as a preprocessor
-macro. On some Alpha implementations the resulting code may execute
-significantly slower than the code generated by default. Since there is
-very little code that depends on the @var{inexact-flag}, you should
-normally not specify this option. Other Alpha compilers call this
-option @option{-ieee_with_inexact}.
+@item -mint32
+@itemx -mno-int16
+@opindex mint32
+@opindex mno-int16
+Use 32-bit @code{int}.
-@item -mfp-trap-mode=@var{trap-mode}
-@opindex mfp-trap-mode
-This option controls what floating-point related traps are enabled.
-Other Alpha compilers call this option @option{-fptm @var{trap-mode}}.
-The trap mode can be set to one of four values:
+@item -mfloat64
+@itemx -mno-float32
+@opindex mfloat64
+@opindex mno-float32
+Use 64-bit @code{float}. This is the default.
-@table @samp
-@item n
-This is the default (normal) setting. The only traps that are enabled
-are the ones that cannot be disabled in software (e.g., division by zero
-trap).
+@item -mfloat32
+@itemx -mno-float64
+@opindex mfloat32
+@opindex mno-float64
+Use 32-bit @code{float}.
-@item u
-In addition to the traps enabled by @samp{n}, underflow traps are enabled
-as well.
+@item -mabshi
+@opindex mabshi
+Use @code{abshi2} pattern. This is the default.
-@item su
-Like @samp{su}, but the instructions are marked to be safe for software
-completion (see Alpha architecture manual for details).
+@item -mno-abshi
+@opindex mno-abshi
+Do not use @code{abshi2} pattern.
-@item sui
-Like @samp{su}, but inexact traps are enabled as well.
-@end table
+@item -mbranch-expensive
+@opindex mbranch-expensive
+Pretend that branches are expensive. This is for experimenting with
+code generation only.
-@item -mfp-rounding-mode=@var{rounding-mode}
-@opindex mfp-rounding-mode
-Selects the IEEE rounding mode. Other Alpha compilers call this option
-@option{-fprm @var{rounding-mode}}. The @var{rounding-mode} can be one
-of:
+@item -mbranch-cheap
+@opindex mbranch-cheap
+Do not pretend that branches are expensive. This is the default.
-@table @samp
-@item n
-Normal IEEE rounding mode. Floating point numbers are rounded towards
-the nearest machine number or towards the even machine number in case
-of a tie.
+@item -msplit
+@opindex msplit
+Generate code for a system with split I&D@.
-@item m
-Round towards minus infinity.
+@item -mno-split
+@opindex mno-split
+Generate code for a system without split I&D@. This is the default.
-@item c
-Chopped rounding mode. Floating point numbers are rounded towards zero.
+@item -munix-asm
+@opindex munix-asm
+Use Unix assembler syntax. This is the default when configured for
+@samp{pdp11-*-bsd}.
-@item d
-Dynamic rounding mode. A field in the floating point control register
-(@var{fpcr}, see Alpha architecture reference manual) controls the
-rounding mode in effect. The C library initializes this register for
-rounding towards plus infinity. Thus, unless your program modifies the
-@var{fpcr}, @samp{d} corresponds to round towards plus infinity.
+@item -mdec-asm
+@opindex mdec-asm
+Use DEC assembler syntax. This is the default when configured for any
+PDP-11 target other than @samp{pdp11-*-bsd}.
@end table
-@item -mtrap-precision=@var{trap-precision}
-@opindex mtrap-precision
-In the Alpha architecture, floating point traps are imprecise. This
-means without software assistance it is impossible to recover from a
-floating trap and program execution normally needs to be terminated.
-GCC can generate code that can assist operating system trap handlers
-in determining the exact location that caused a floating point trap.
-Depending on the requirements of an application, different levels of
-precisions can be selected:
+@node picoChip Options
+@subsection picoChip Options
+@cindex picoChip options
-@table @samp
-@item p
-Program precision. This option is the default and means a trap handler
-can only identify which program caused a floating point exception.
+These @samp{-m} options are defined for picoChip implementations:
-@item f
-Function precision. The trap handler can determine the function that
-caused a floating point exception.
+@table @gcctabopt
+
+@item -mae=@var{ae_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling
+parameters for array element type @var{ae_type}. Supported values
+for @var{ae_type} are @samp{ANY}, @samp{MUL}, and @samp{MAC}.
+
+@option{-mae=ANY} selects a completely generic AE type. Code
+generated with this option will run on any of the other AE types. The
+code will not be as efficient as it would be if compiled for a specific
+AE type, and some types of operation (e.g., multiplication) will not
+work properly on all types of AE.
+
+@option{-mae=MUL} selects a MUL AE type. This is the most useful AE type
+for compiled code, and is the default.
+
+@option{-mae=MAC} selects a DSP-style MAC AE. Code compiled with this
+option may suffer from poor performance of byte (char) manipulation,
+since the DSP AE does not provide hardware support for byte load/stores.
+
+@item -msymbol-as-address
+Enable the compiler to directly use a symbol name as an address in a
+load/store instruction, without first loading it into a
+register. Typically, the use of this option will generate larger
+programs, which run faster than when the option isn't used. However, the
+results vary from program to program, so it is left as a user option,
+rather than being permanently enabled.
+
+@item -mno-inefficient-warnings
+Disables warnings about the generation of inefficient code. These
+warnings can be generated, for example, when compiling code which
+performs byte-level memory operations on the MAC AE type. The MAC AE has
+no hardware support for byte-level memory operations, so all byte
+load/stores must be synthesized from word load/store operations. This is
+inefficient and a warning will be generated indicating to the programmer
+that they should rewrite the code to avoid byte operations, or to target
+an AE type which has the necessary hardware support. This option enables
+the warning to be turned off.
-@item i
-Instruction precision. The trap handler can determine the exact
-instruction that caused a floating point exception.
@end table
-Other Alpha compilers provide the equivalent options called
-@option{-scope_safe} and @option{-resumption_safe}.
+@node PowerPC Options
+@subsection PowerPC Options
+@cindex PowerPC options
-@item -mieee-conformant
-@opindex mieee-conformant
-This option marks the generated code as IEEE conformant. You must not
-use this option unless you also specify @option{-mtrap-precision=i} and either
-@option{-mfp-trap-mode=su} or @option{-mfp-trap-mode=sui}. Its only effect
-is to emit the line @samp{.eflag 48} in the function prologue of the
-generated assembly file. Under DEC Unix, this has the effect that
-IEEE-conformant math library routines will be linked in.
+These are listed under @xref{RS/6000 and PowerPC Options}.
-@item -mbuild-constants
-@opindex mbuild-constants
-Normally GCC examines a 32- or 64-bit integer constant to
-see if it can construct it from smaller constants in two or three
-instructions. If it cannot, it will output the constant as a literal and
-generate code to load it from the data segment at runtime.
+@node RS/6000 and PowerPC Options
+@subsection IBM RS/6000 and PowerPC Options
+@cindex RS/6000 and PowerPC Options
+@cindex IBM RS/6000 and PowerPC Options
-Use this option to require GCC to construct @emph{all} integer constants
-using code, even if it takes more instructions (the maximum is six).
+These @samp{-m} options are defined for the IBM RS/6000 and PowerPC:
+@table @gcctabopt
+@item -mpower
+@itemx -mno-power
+@itemx -mpower2
+@itemx -mno-power2
+@itemx -mpowerpc
+@itemx -mno-powerpc
+@itemx -mpowerpc-gpopt
+@itemx -mno-powerpc-gpopt
+@itemx -mpowerpc-gfxopt
+@itemx -mno-powerpc-gfxopt
+@itemx -mpowerpc64
+@itemx -mno-powerpc64
+@itemx -mmfcrf
+@itemx -mno-mfcrf
+@itemx -mpopcntb
+@itemx -mno-popcntb
+@itemx -mfprnd
+@itemx -mno-fprnd
+@itemx -mcmpb
+@itemx -mno-cmpb
+@itemx -mmfpgpr
+@itemx -mno-mfpgpr
+@itemx -mhard-dfp
+@itemx -mno-hard-dfp
+@opindex mpower
+@opindex mno-power
+@opindex mpower2
+@opindex mno-power2
+@opindex mpowerpc
+@opindex mno-powerpc
+@opindex mpowerpc-gpopt
+@opindex mno-powerpc-gpopt
+@opindex mpowerpc-gfxopt
+@opindex mno-powerpc-gfxopt
+@opindex mpowerpc64
+@opindex mno-powerpc64
+@opindex mmfcrf
+@opindex mno-mfcrf
+@opindex mpopcntb
+@opindex mno-popcntb
+@opindex mfprnd
+@opindex mno-fprnd
+@opindex mcmpb
+@opindex mno-cmpb
+@opindex mmfpgpr
+@opindex mno-mfpgpr
+@opindex mhard-dfp
+@opindex mno-hard-dfp
+GCC supports two related instruction set architectures for the
+RS/6000 and PowerPC@. The @dfn{POWER} instruction set are those
+instructions supported by the @samp{rios} chip set used in the original
+RS/6000 systems and the @dfn{PowerPC} instruction set is the
+architecture of the Freescale MPC5xx, MPC6xx, MPC8xx microprocessors, and
+the IBM 4xx, 6xx, and follow-on microprocessors.
-You would typically use this option to build a shared library dynamic
-loader. Itself a shared library, it must relocate itself in memory
-before it can find the variables and constants in its own data segment.
+Neither architecture is a subset of the other. However there is a
+large common subset of instructions supported by both. An MQ
+register is included in processors supporting the POWER architecture.
-@item -malpha-as
-@itemx -mgas
-@opindex malpha-as
-@opindex mgas
-Select whether to generate code to be assembled by the vendor-supplied
-assembler (@option{-malpha-as}) or by the GNU assembler @option{-mgas}.
+You use these options to specify which instructions are available on the
+processor you are using. The default value of these options is
+determined when configuring GCC@. Specifying the
+@option{-mcpu=@var{cpu_type}} overrides the specification of these
+options. We recommend you use the @option{-mcpu=@var{cpu_type}} option
+rather than the options listed above.
-@item -mbwx
-@itemx -mno-bwx
-@itemx -mcix
-@itemx -mno-cix
-@itemx -mfix
-@itemx -mno-fix
-@itemx -mmax
-@itemx -mno-max
-@opindex mbwx
-@opindex mno-bwx
-@opindex mcix
-@opindex mno-cix
-@opindex mfix
-@opindex mno-fix
-@opindex mmax
-@opindex mno-max
-Indicate whether GCC should generate code to use the optional BWX,
-CIX, FIX and MAX instruction sets. The default is to use the instruction
-sets supported by the CPU type specified via @option{-mcpu=} option or that
-of the CPU on which GCC was built if none was specified.
+The @option{-mpower} option allows GCC to generate instructions that
+are found only in the POWER architecture and to use the MQ register.
+Specifying @option{-mpower2} implies @option{-power} and also allows GCC
+to generate instructions that are present in the POWER2 architecture but
+not the original POWER architecture.
-@item -mfloat-vax
-@itemx -mfloat-ieee
-@opindex mfloat-vax
-@opindex mfloat-ieee
-Generate code that uses (does not use) VAX F and G floating point
-arithmetic instead of IEEE single and double precision.
+The @option{-mpowerpc} option allows GCC to generate instructions that
+are found only in the 32-bit subset of the PowerPC architecture.
+Specifying @option{-mpowerpc-gpopt} implies @option{-mpowerpc} and also allows
+GCC to use the optional PowerPC architecture instructions in the
+General Purpose group, including floating-point square root. Specifying
+@option{-mpowerpc-gfxopt} implies @option{-mpowerpc} and also allows GCC to
+use the optional PowerPC architecture instructions in the Graphics
+group, including floating-point select.
-@item -mexplicit-relocs
-@itemx -mno-explicit-relocs
-@opindex mexplicit-relocs
-@opindex mno-explicit-relocs
-Older Alpha assemblers provided no way to generate symbol relocations
-except via assembler macros. Use of these macros does not allow
-optimial instruction scheduling. GNU binutils as of version 2.12
-supports a new syntax that allows the compiler to explicitly mark
-which relocations should apply to which instructions. This option
-is mostly useful for debugging, as GCC detects the capabilities of
-the assembler when it is built and sets the default accordingly.
+The @option{-mmfcrf} option allows GCC to generate the move from
+condition register field instruction implemented on the POWER4
+processor and other processors that support the PowerPC V2.01
+architecture.
+The @option{-mpopcntb} option allows GCC to generate the popcount and
+double precision FP reciprocal estimate instruction implemented on the
+POWER5 processor and other processors that support the PowerPC V2.02
+architecture.
+The @option{-mfprnd} option allows GCC to generate the FP round to
+integer instructions implemented on the POWER5+ processor and other
+processors that support the PowerPC V2.03 architecture.
+The @option{-mcmpb} option allows GCC to generate the compare bytes
+instruction implemented on the POWER6 processor and other processors
+that support the PowerPC V2.05 architecture.
+The @option{-mmfpgpr} option allows GCC to generate the FP move to/from
+general purpose register instructions implemented on the POWER6X
+processor and other processors that support the extended PowerPC V2.05
+architecture.
+The @option{-mhard-dfp} option allows GCC to generate the decimal floating
+point instructions implemented on some POWER processors.
-@item -msmall-data
-@itemx -mlarge-data
-@opindex msmall-data
-@opindex mlarge-data
-When @option{-mexplicit-relocs} is in effect, static data is
-accessed via @dfn{gp-relative} relocations. When @option{-msmall-data}
-is used, objects 8 bytes long or smaller are placed in a @dfn{small data area}
-(the @code{.sdata} and @code{.sbss} sections) and are accessed via
-16-bit relocations off of the @code{$gp} register. This limits the
-size of the small data area to 64KB, but allows the variables to be
-directly accessed via a single instruction.
+The @option{-mpowerpc64} option allows GCC to generate the additional
+64-bit instructions that are found in the full PowerPC64 architecture
+and to treat GPRs as 64-bit, doubleword quantities. GCC defaults to
+@option{-mno-powerpc64}.
-The default is @option{-mlarge-data}. With this option the data area
-is limited to just below 2GB. Programs that require more than 2GB of
-data must use @code{malloc} or @code{mmap} to allocate the data in the
-heap instead of in the program's data segment.
+If you specify both @option{-mno-power} and @option{-mno-powerpc}, GCC
+will use only the instructions in the common subset of both
+architectures plus some special AIX common-mode calls, and will not use
+the MQ register. Specifying both @option{-mpower} and @option{-mpowerpc}
+permits GCC to use any instruction from either architecture and to
+allow use of the MQ register; specify this for the Motorola MPC601.
-When generating code for shared libraries, @option{-fpic} implies
-@option{-msmall-data} and @option{-fPIC} implies @option{-mlarge-data}.
+@item -mnew-mnemonics
+@itemx -mold-mnemonics
+@opindex mnew-mnemonics
+@opindex mold-mnemonics
+Select which mnemonics to use in the generated assembler code. With
+@option{-mnew-mnemonics}, GCC uses the assembler mnemonics defined for
+the PowerPC architecture. With @option{-mold-mnemonics} it uses the
+assembler mnemonics defined for the POWER architecture. Instructions
+defined in only one architecture have only one mnemonic; GCC uses that
+mnemonic irrespective of which of these options is specified.
+
+GCC defaults to the mnemonics appropriate for the architecture in
+use. Specifying @option{-mcpu=@var{cpu_type}} sometimes overrides the
+value of these option. Unless you are building a cross-compiler, you
+should normally not specify either @option{-mnew-mnemonics} or
+@option{-mold-mnemonics}, but should instead accept the default.
@item -mcpu=@var{cpu_type}
@opindex mcpu
-Set the instruction set and instruction scheduling parameters for
-machine type @var{cpu_type}. You can specify either the @samp{EV}
-style name or the corresponding chip number. GCC supports scheduling
-parameters for the EV4, EV5 and EV6 family of processors and will
-choose the default values for the instruction set from the processor
-you specify. If you do not specify a processor type, GCC will default
-to the processor on which the compiler was built.
+Set architecture type, register usage, choice of mnemonics, and
+instruction scheduling parameters for machine type @var{cpu_type}.
+Supported values for @var{cpu_type} are @samp{401}, @samp{403},
+@samp{405}, @samp{405fp}, @samp{440}, @samp{440fp}, @samp{464}, @samp{464fp},
+@samp{505}, @samp{601}, @samp{602}, @samp{603}, @samp{603e}, @samp{604},
+@samp{604e}, @samp{620}, @samp{630}, @samp{740}, @samp{7400},
+@samp{7450}, @samp{750}, @samp{801}, @samp{821}, @samp{823},
+@samp{860}, @samp{970}, @samp{8540}, @samp{e300c2}, @samp{e300c3},
+@samp{e500mc}, @samp{ec603e}, @samp{G3}, @samp{G4}, @samp{G5},
+@samp{power}, @samp{power2}, @samp{power3}, @samp{power4},
+@samp{power5}, @samp{power5+}, @samp{power6}, @samp{power6x}, @samp{power7}
+@samp{common}, @samp{powerpc}, @samp{powerpc64}, @samp{rios},
+@samp{rios1}, @samp{rios2}, @samp{rsc}, and @samp{rs64}.
-Supported values for @var{cpu_type} are
+@option{-mcpu=common} selects a completely generic processor. Code
+generated under this option will run on any POWER or PowerPC processor.
+GCC will use only the instructions in the common subset of both
+architectures, and will not use the MQ register. GCC assumes a generic
+processor model for scheduling purposes.
-@table @samp
-@item ev4
-@item ev45
-@itemx 21064
-Schedules as an EV4 and has no instruction set extensions.
+@option{-mcpu=power}, @option{-mcpu=power2}, @option{-mcpu=powerpc}, and
+@option{-mcpu=powerpc64} specify generic POWER, POWER2, pure 32-bit
+PowerPC (i.e., not MPC601), and 64-bit PowerPC architecture machine
+types, with an appropriate, generic processor model assumed for
+scheduling purposes.
-@item ev5
-@itemx 21164
-Schedules as an EV5 and has no instruction set extensions.
+The other options specify a specific processor. Code generated under
+those options will run best on that processor, and may not run at all on
+others.
-@item ev56
-@itemx 21164a
-Schedules as an EV5 and supports the BWX extension.
+The @option{-mcpu} options automatically enable or disable the
+following options:
-@item pca56
-@itemx 21164pc
-@itemx 21164PC
-Schedules as an EV5 and supports the BWX and MAX extensions.
+@gccoptlist{-maltivec -mfprnd -mhard-float -mmfcrf -mmultiple @gol
+-mnew-mnemonics -mpopcntb -mpower -mpower2 -mpowerpc64 @gol
+-mpowerpc-gpopt -mpowerpc-gfxopt -msingle-float -mdouble-float @gol
+-msimple-fpu -mstring -mmulhw -mdlmzb -mmfpgpr}
-@item ev6
-@itemx 21264
-Schedules as an EV6 and supports the BWX, FIX, and MAX extensions.
+The particular options set for any particular CPU will vary between
+compiler versions, depending on what setting seems to produce optimal
+code for that CPU; it doesn't necessarily reflect the actual hardware's
+capabilities. If you wish to set an individual option to a particular
+value, you may specify it after the @option{-mcpu} option, like
+@samp{-mcpu=970 -mno-altivec}.
-@item ev67
-@item 21264a
-Schedules as an EV6 and supports the BWX, CIX, FIX, and MAX extensions.
-@end table
+On AIX, the @option{-maltivec} and @option{-mpowerpc64} options are
+not enabled or disabled by the @option{-mcpu} option at present because
+AIX does not have full support for these options. You may still
+enable or disable them individually if you're sure it'll work in your
+environment.
@item -mtune=@var{cpu_type}
@opindex mtune
-Set only the instruction scheduling parameters for machine type
-@var{cpu_type}. The instruction set is not changed.
-
-@item -mmemory-latency=@var{time}
-@opindex mmemory-latency
-Sets the latency the scheduler should assume for typical memory
-references as seen by the application. This number is highly
-dependent on the memory access patterns used by the application
-and the size of the external cache on the machine.
-
-Valid options for @var{time} are
-
-@table @samp
-@item @var{number}
-A decimal number representing clock cycles.
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the architecture type, register usage, or
+choice of mnemonics, as @option{-mcpu=@var{cpu_type}} would. The same
+values for @var{cpu_type} are used for @option{-mtune} as for
+@option{-mcpu}. If both are specified, the code generated will use the
+architecture, registers, and mnemonics set by @option{-mcpu}, but the
+scheduling parameters set by @option{-mtune}.
-@item L1
-@itemx L2
-@itemx L3
-@itemx main
-The compiler contains estimates of the number of clock cycles for
-``typical'' EV4 & EV5 hardware for the Level 1, 2 & 3 caches
-(also called Dcache, Scache, and Bcache), as well as to main memory.
-Note that L3 is only valid for EV5.
+@item -mswdiv
+@itemx -mno-swdiv
+@opindex mswdiv
+@opindex mno-swdiv
+Generate code to compute division as reciprocal estimate and iterative
+refinement, creating opportunities for increased throughput. This
+feature requires: optional PowerPC Graphics instruction set for single
+precision and FRE instruction for double precision, assuming divides
+cannot generate user-visible traps, and the domain values not include
+Infinities, denormals or zero denominator.
-@end table
-@end table
+@item -maltivec
+@itemx -mno-altivec
+@opindex maltivec
+@opindex mno-altivec
+Generate code that uses (does not use) AltiVec instructions, and also
+enable the use of built-in functions that allow more direct access to
+the AltiVec instruction set. You may also need to set
+@option{-mabi=altivec} to adjust the current ABI with AltiVec ABI
+enhancements.
-@node DEC Alpha/VMS Options
-@subsection DEC Alpha/VMS Options
+@item -mvrsave
+@itemx -mno-vrsave
+@opindex mvrsave
+@opindex mno-vrsave
+Generate VRSAVE instructions when generating AltiVec code.
+
+@item -mgen-cell-microcode
+@opindex mgen-cell-microcode
+Generate Cell microcode instructions
+
+@item -mwarn-cell-microcode
+@opindex mwarn-cell-microcode
+Warning when a Cell microcode instruction is going to emitted. An example
+of a Cell microcode instruction is a variable shift.
+
+@item -msecure-plt
+@opindex msecure-plt
+Generate code that allows ld and ld.so to build executables and shared
+libraries with non-exec .plt and .got sections. This is a PowerPC
+32-bit SYSV ABI option.
+
+@item -mbss-plt
+@opindex mbss-plt
+Generate code that uses a BSS .plt section that ld.so fills in, and
+requires .plt and .got sections that are both writable and executable.
+This is a PowerPC 32-bit SYSV ABI option.
+
+@item -misel
+@itemx -mno-isel
+@opindex misel
+@opindex mno-isel
+This switch enables or disables the generation of ISEL instructions.
+
+@item -misel=@var{yes/no}
+This switch has been deprecated. Use @option{-misel} and
+@option{-mno-isel} instead.
+
+@item -mspe
+@itemx -mno-spe
+@opindex mspe
+@opindex mno-spe
+This switch enables or disables the generation of SPE simd
+instructions.
-These @samp{-m} options are defined for the DEC Alpha/VMS implementations:
+@item -mpaired
+@itemx -mno-paired
+@opindex mpaired
+@opindex mno-paired
+This switch enables or disables the generation of PAIRED simd
+instructions.
-@table @gcctabopt
-@item -mvms-return-codes
-@opindex mvms-return-codes
-Return VMS condition codes from main. The default is to return POSIX
-style condition (e.g.@ error) codes.
-@end table
+@item -mspe=@var{yes/no}
+This option has been deprecated. Use @option{-mspe} and
+@option{-mno-spe} instead.
-@node Clipper Options
-@subsection Clipper Options
+@item -mfloat-gprs=@var{yes/single/double/no}
+@itemx -mfloat-gprs
+@opindex mfloat-gprs
+This switch enables or disables the generation of floating point
+operations on the general purpose registers for architectures that
+support it.
-These @samp{-m} options are defined for the Clipper implementations:
+The argument @var{yes} or @var{single} enables the use of
+single-precision floating point operations.
-@table @gcctabopt
-@item -mc300
-@opindex mc300
-Produce code for a C300 Clipper processor. This is the default.
-
-@item -mc400
-@opindex mc400
-Produce code for a C400 Clipper processor, i.e.@: use floating point
-registers f8--f15.
-@end table
+The argument @var{double} enables the use of single and
+double-precision floating point operations.
-@node H8/300 Options
-@subsection H8/300 Options
+The argument @var{no} disables floating point operations on the
+general purpose registers.
-These @samp{-m} options are defined for the H8/300 implementations:
+This option is currently only available on the MPC854x.
-@table @gcctabopt
-@item -mrelax
-@opindex mrelax
-Shorten some address references at link time, when possible; uses the
-linker option @option{-relax}. @xref{H8/300,, @code{ld} and the H8/300,
-ld.info, Using ld}, for a fuller description.
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for 32-bit or 64-bit environments of Darwin and SVR4
+targets (including GNU/Linux). The 32-bit environment sets int, long
+and pointer to 32 bits and generates code that runs on any PowerPC
+variant. The 64-bit environment sets int to 32 bits and long and
+pointer to 64 bits, and generates code for PowerPC64, as for
+@option{-mpowerpc64}.
-@item -mh
-@opindex mh
-Generate code for the H8/300H@.
+@item -mfull-toc
+@itemx -mno-fp-in-toc
+@itemx -mno-sum-in-toc
+@itemx -mminimal-toc
+@opindex mfull-toc
+@opindex mno-fp-in-toc
+@opindex mno-sum-in-toc
+@opindex mminimal-toc
+Modify generation of the TOC (Table Of Contents), which is created for
+every executable file. The @option{-mfull-toc} option is selected by
+default. In that case, GCC will allocate at least one TOC entry for
+each unique non-automatic variable reference in your program. GCC
+will also place floating-point constants in the TOC@. However, only
+16,384 entries are available in the TOC@.
-@item -ms
-@opindex ms
-Generate code for the H8/S@.
+If you receive a linker error message that saying you have overflowed
+the available TOC space, you can reduce the amount of TOC space used
+with the @option{-mno-fp-in-toc} and @option{-mno-sum-in-toc} options.
+@option{-mno-fp-in-toc} prevents GCC from putting floating-point
+constants in the TOC and @option{-mno-sum-in-toc} forces GCC to
+generate code to calculate the sum of an address and a constant at
+run-time instead of putting that sum into the TOC@. You may specify one
+or both of these options. Each causes GCC to produce very slightly
+slower and larger code at the expense of conserving TOC space.
-@item -ms2600
-@opindex ms2600
-Generate code for the H8/S2600. This switch must be used with @option{-ms}.
+If you still run out of space in the TOC even when you specify both of
+these options, specify @option{-mminimal-toc} instead. This option causes
+GCC to make only one TOC entry for every file. When you specify this
+option, GCC will produce code that is slower and larger but which
+uses extremely little TOC space. You may wish to use this option
+only on files that contain less frequently executed code.
-@item -mint32
-@opindex mint32
-Make @code{int} data 32 bits by default.
+@item -maix64
+@itemx -maix32
+@opindex maix64
+@opindex maix32
+Enable 64-bit AIX ABI and calling convention: 64-bit pointers, 64-bit
+@code{long} type, and the infrastructure needed to support them.
+Specifying @option{-maix64} implies @option{-mpowerpc64} and
+@option{-mpowerpc}, while @option{-maix32} disables the 64-bit ABI and
+implies @option{-mno-powerpc64}. GCC defaults to @option{-maix32}.
-@item -malign-300
-@opindex malign-300
-On the H8/300H and H8/S, use the same alignment rules as for the H8/300.
-The default for the H8/300H and H8/S is to align longs and floats on 4
-byte boundaries.
-@option{-malign-300} causes them to be aligned on 2 byte boundaries.
-This option has no effect on the H8/300.
-@end table
+@item -mxl-compat
+@itemx -mno-xl-compat
+@opindex mxl-compat
+@opindex mno-xl-compat
+Produce code that conforms more closely to IBM XL compiler semantics
+when using AIX-compatible ABI@. Pass floating-point arguments to
+prototyped functions beyond the register save area (RSA) on the stack
+in addition to argument FPRs. Do not assume that most significant
+double in 128-bit long double value is properly rounded when comparing
+values and converting to double. Use XL symbol names for long double
+support routines.
+
+The AIX calling convention was extended but not initially documented to
+handle an obscure K&R C case of calling a function that takes the
+address of its arguments with fewer arguments than declared. IBM XL
+compilers access floating point arguments which do not fit in the
+RSA from the stack when a subroutine is compiled without
+optimization. Because always storing floating-point arguments on the
+stack is inefficient and rarely needed, this option is not enabled by
+default and only is necessary when calling subroutines compiled by IBM
+XL compilers without optimization.
-@node SH Options
-@subsection SH Options
+@item -mpe
+@opindex mpe
+Support @dfn{IBM RS/6000 SP} @dfn{Parallel Environment} (PE)@. Link an
+application written to use message passing with special startup code to
+enable the application to run. The system must have PE installed in the
+standard location (@file{/usr/lpp/ppe.poe/}), or the @file{specs} file
+must be overridden with the @option{-specs=} option to specify the
+appropriate directory location. The Parallel Environment does not
+support threads, so the @option{-mpe} option and the @option{-pthread}
+option are incompatible.
-These @samp{-m} options are defined for the SH implementations:
+@item -malign-natural
+@itemx -malign-power
+@opindex malign-natural
+@opindex malign-power
+On AIX, 32-bit Darwin, and 64-bit PowerPC GNU/Linux, the option
+@option{-malign-natural} overrides the ABI-defined alignment of larger
+types, such as floating-point doubles, on their natural size-based boundary.
+The option @option{-malign-power} instructs GCC to follow the ABI-specified
+alignment rules. GCC defaults to the standard alignment defined in the ABI@.
-@table @gcctabopt
-@item -m1
-@opindex m1
-Generate code for the SH1.
+On 64-bit Darwin, natural alignment is the default, and @option{-malign-power}
+is not supported.
-@item -m2
-@opindex m2
-Generate code for the SH2.
+@item -msoft-float
+@itemx -mhard-float
+@opindex msoft-float
+@opindex mhard-float
+Generate code that does not use (uses) the floating-point register set.
+Software floating point emulation is provided if you use the
+@option{-msoft-float} option, and pass the option to GCC when linking.
-@item -m3
-@opindex m3
-Generate code for the SH3.
+@item -msingle-float
+@itemx -mdouble-float
+@opindex msingle-float
+@opindex mdouble-float
+Generate code for single or double-precision floating point operations.
+@option{-mdouble-float} implies @option{-msingle-float}.
-@item -m3e
-@opindex m3e
-Generate code for the SH3e.
+@item -msimple-fpu
+@opindex msimple-fpu
+Do not generate sqrt and div instructions for hardware floating point unit.
-@item -m4-nofpu
-@opindex m4-nofpu
-Generate code for the SH4 without a floating-point unit.
+@item -mfpu
+@opindex mfpu
+Specify type of floating point unit. Valid values are @var{sp_lite}
+(equivalent to -msingle-float -msimple-fpu), @var{dp_lite} (equivalent
+to -mdouble-float -msimple-fpu), @var{sp_full} (equivalent to -msingle-float),
+and @var{dp_full} (equivalent to -mdouble-float).
-@item -m4-single-only
-@opindex m4-single-only
-Generate code for the SH4 with a floating-point unit that only
-supports single-precision arithmetic.
+@item -mxilinx-fpu
+@opindex mxilinx-fpu
+Perform optimizations for floating point unit on Xilinx PPC 405/440.
-@item -m4-single
-@opindex m4-single
-Generate code for the SH4 assuming the floating-point unit is in
-single-precision mode by default.
+@item -mmultiple
+@itemx -mno-multiple
+@opindex mmultiple
+@opindex mno-multiple
+Generate code that uses (does not use) the load multiple word
+instructions and the store multiple word instructions. These
+instructions are generated by default on POWER systems, and not
+generated on PowerPC systems. Do not use @option{-mmultiple} on little
+endian PowerPC systems, since those instructions do not work when the
+processor is in little endian mode. The exceptions are PPC740 and
+PPC750 which permit the instructions usage in little endian mode.
-@item -m4
-@opindex m4
-Generate code for the SH4.
+@item -mstring
+@itemx -mno-string
+@opindex mstring
+@opindex mno-string
+Generate code that uses (does not use) the load string instructions
+and the store string word instructions to save multiple registers and
+do small block moves. These instructions are generated by default on
+POWER systems, and not generated on PowerPC systems. Do not use
+@option{-mstring} on little endian PowerPC systems, since those
+instructions do not work when the processor is in little endian mode.
+The exceptions are PPC740 and PPC750 which permit the instructions
+usage in little endian mode.
-@item -mb
-@opindex mb
-Compile code for the processor in big endian mode.
+@item -mupdate
+@itemx -mno-update
+@opindex mupdate
+@opindex mno-update
+Generate code that uses (does not use) the load or store instructions
+that update the base register to the address of the calculated memory
+location. These instructions are generated by default. If you use
+@option{-mno-update}, there is a small window between the time that the
+stack pointer is updated and the address of the previous frame is
+stored, which means code that walks the stack frame across interrupts or
+signals may get corrupted data.
-@item -ml
-@opindex ml
-Compile code for the processor in little endian mode.
+@item -mavoid-indexed-addresses
+@item -mno-avoid-indexed-addresses
+@opindex mavoid-indexed-addresses
+@opindex mno-avoid-indexed-addresses
+Generate code that tries to avoid (not avoid) the use of indexed load
+or store instructions. These instructions can incur a performance
+penalty on Power6 processors in certain situations, such as when
+stepping through large arrays that cross a 16M boundary. This option
+is enabled by default when targetting Power6 and disabled otherwise.
-@item -mdalign
-@opindex mdalign
-Align doubles at 64-bit boundaries. Note that this changes the calling
-conventions, and thus some functions from the standard C library will
-not work unless you recompile it first with @option{-mdalign}.
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating point multiply and
+accumulate instructions. These instructions are generated by default if
+hardware floating is used.
-@item -mrelax
-@opindex mrelax
-Shorten some address references at link time, when possible; uses the
-linker option @option{-relax}.
+@item -mmulhw
+@itemx -mno-mulhw
+@opindex mmulhw
+@opindex mno-mulhw
+Generate code that uses (does not use) the half-word multiply and
+multiply-accumulate instructions on the IBM 405, 440 and 464 processors.
+These instructions are generated by default when targetting those
+processors.
-@item -mbigtable
-@opindex mbigtable
-Use 32-bit offsets in @code{switch} tables. The default is to use
-16-bit offsets.
+@item -mdlmzb
+@itemx -mno-dlmzb
+@opindex mdlmzb
+@opindex mno-dlmzb
+Generate code that uses (does not use) the string-search @samp{dlmzb}
+instruction on the IBM 405, 440 and 464 processors. This instruction is
+generated by default when targetting those processors.
-@item -mfmovd
-@opindex mfmovd
-Enable the use of the instruction @code{fmovd}.
+@item -mno-bit-align
+@itemx -mbit-align
+@opindex mno-bit-align
+@opindex mbit-align
+On System V.4 and embedded PowerPC systems do not (do) force structures
+and unions that contain bit-fields to be aligned to the base type of the
+bit-field.
-@item -mhitachi
-@opindex mhitachi
-Comply with the calling conventions defined by Hitachi.
+For example, by default a structure containing nothing but 8
+@code{unsigned} bit-fields of length 1 would be aligned to a 4 byte
+boundary and have a size of 4 bytes. By using @option{-mno-bit-align},
+the structure would be aligned to a 1 byte boundary and be one byte in
+size.
-@item -mnomacsave
-@opindex mnomacsave
-Mark the @code{MAC} register as call-clobbered, even if
-@option{-mhitachi} is given.
+@item -mno-strict-align
+@itemx -mstrict-align
+@opindex mno-strict-align
+@opindex mstrict-align
+On System V.4 and embedded PowerPC systems do not (do) assume that
+unaligned memory references will be handled by the system.
-@item -mieee
-@opindex mieee
-Increase IEEE-compliance of floating-point code.
+@item -mrelocatable
+@itemx -mno-relocatable
+@opindex mrelocatable
+@opindex mno-relocatable
+On embedded PowerPC systems generate code that allows (does not allow)
+the program to be relocated to a different address at runtime. If you
+use @option{-mrelocatable} on any module, all objects linked together must
+be compiled with @option{-mrelocatable} or @option{-mrelocatable-lib}.
-@item -misize
-@opindex misize
-Dump instruction size and location in the assembly code.
+@item -mrelocatable-lib
+@itemx -mno-relocatable-lib
+@opindex mrelocatable-lib
+@opindex mno-relocatable-lib
+On embedded PowerPC systems generate code that allows (does not allow)
+the program to be relocated to a different address at runtime. Modules
+compiled with @option{-mrelocatable-lib} can be linked with either modules
+compiled without @option{-mrelocatable} and @option{-mrelocatable-lib} or
+with modules compiled with the @option{-mrelocatable} options.
-@item -mpadstruct
-@opindex mpadstruct
-This option is deprecated. It pads structures to multiple of 4 bytes,
-which is incompatible with the SH ABI@.
+@item -mno-toc
+@itemx -mtoc
+@opindex mno-toc
+@opindex mtoc
+On System V.4 and embedded PowerPC systems do not (do) assume that
+register 2 contains a pointer to a global area pointing to the addresses
+used in the program.
-@item -mspace
-@opindex mspace
-Optimize for space instead of speed. Implied by @option{-Os}.
+@item -mlittle
+@itemx -mlittle-endian
+@opindex mlittle
+@opindex mlittle-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in little endian mode. The @option{-mlittle-endian} option is
+the same as @option{-mlittle}.
-@item -mprefergot
-@opindex mprefergot
-When generating position-independent code, emit function calls using
-the Global Offset Table instead of the Procedure Linkage Table.
+@item -mbig
+@itemx -mbig-endian
+@opindex mbig
+@opindex mbig-endian
+On System V.4 and embedded PowerPC systems compile code for the
+processor in big endian mode. The @option{-mbig-endian} option is
+the same as @option{-mbig}.
-@item -musermode
-@opindex musermode
-Generate a library function call to invalidate instruction cache
-entries, after fixing up a trampoline. This library function call
-doesn't assume it can write to the whole memory address space. This
-is the default when the target is @code{sh-*-linux*}.
-@end table
+@item -mdynamic-no-pic
+@opindex mdynamic-no-pic
+On Darwin and Mac OS X systems, compile code so that it is not
+relocatable, but that its external references are relocatable. The
+resulting code is suitable for applications, but not shared
+libraries.
+
+@item -mprioritize-restricted-insns=@var{priority}
+@opindex mprioritize-restricted-insns
+This option controls the priority that is assigned to
+dispatch-slot restricted instructions during the second scheduling
+pass. The argument @var{priority} takes the value @var{0/1/2} to assign
+@var{no/highest/second-highest} priority to dispatch slot restricted
+instructions.
-@node System V Options
-@subsection Options for System V
+@item -msched-costly-dep=@var{dependence_type}
+@opindex msched-costly-dep
+This option controls which dependences are considered costly
+by the target during instruction scheduling. The argument
+@var{dependence_type} takes one of the following values:
+@var{no}: no dependence is costly,
+@var{all}: all dependences are costly,
+@var{true_store_to_load}: a true dependence from store to load is costly,
+@var{store_to_load}: any dependence from store to load is costly,
+@var{number}: any dependence which latency >= @var{number} is costly.
+
+@item -minsert-sched-nops=@var{scheme}
+@opindex minsert-sched-nops
+This option controls which nop insertion scheme will be used during
+the second scheduling pass. The argument @var{scheme} takes one of the
+following values:
+@var{no}: Don't insert nops.
+@var{pad}: Pad with nops any dispatch group which has vacant issue slots,
+according to the scheduler's grouping.
+@var{regroup_exact}: Insert nops to force costly dependent insns into
+separate groups. Insert exactly as many nops as needed to force an insn
+to a new group, according to the estimated processor grouping.
+@var{number}: Insert nops to force costly dependent insns into
+separate groups. Insert @var{number} nops to force an insn to a new group.
-These additional options are available on System V Release 4 for
-compatibility with other compilers on those systems:
+@item -mcall-sysv
+@opindex mcall-sysv
+On System V.4 and embedded PowerPC systems compile code using calling
+conventions that adheres to the March 1995 draft of the System V
+Application Binary Interface, PowerPC processor supplement. This is the
+default unless you configured GCC using @samp{powerpc-*-eabiaix}.
-@table @gcctabopt
-@item -G
-@opindex G
-Create a shared object.
-It is recommended that @option{-symbolic} or @option{-shared} be used instead.
+@item -mcall-sysv-eabi
+@opindex mcall-sysv-eabi
+Specify both @option{-mcall-sysv} and @option{-meabi} options.
-@item -Qy
-@opindex Qy
-Identify the versions of each tool used by the compiler, in a
-@code{.ident} assembler directive in the output.
+@item -mcall-sysv-noeabi
+@opindex mcall-sysv-noeabi
+Specify both @option{-mcall-sysv} and @option{-mno-eabi} options.
-@item -Qn
-@opindex Qn
-Refrain from adding @code{.ident} directives to the output file (this is
-the default).
+@item -mcall-solaris
+@opindex mcall-solaris
+On System V.4 and embedded PowerPC systems compile code for the Solaris
+operating system.
-@item -YP,@var{dirs}
-@opindex YP
-Search the directories @var{dirs}, and no others, for libraries
-specified with @option{-l}.
+@item -mcall-linux
+@opindex mcall-linux
+On System V.4 and embedded PowerPC systems compile code for the
+Linux-based GNU system.
-@item -Ym,@var{dir}
-@opindex Ym
-Look in the directory @var{dir} to find the M4 preprocessor.
-The assembler uses this option.
-@c This is supposed to go with a -Yd for predefined M4 macro files, but
-@c the generic assembler that comes with Solaris takes just -Ym.
-@end table
+@item -mcall-gnu
+@opindex mcall-gnu
+On System V.4 and embedded PowerPC systems compile code for the
+Hurd-based GNU system.
-@node TMS320C3x/C4x Options
-@subsection TMS320C3x/C4x Options
-@cindex TMS320C3x/C4x Options
+@item -mcall-netbsd
+@opindex mcall-netbsd
+On System V.4 and embedded PowerPC systems compile code for the
+NetBSD operating system.
-These @samp{-m} options are defined for TMS320C3x/C4x implementations:
+@item -maix-struct-return
+@opindex maix-struct-return
+Return all structures in memory (as specified by the AIX ABI)@.
-@table @gcctabopt
+@item -msvr4-struct-return
+@opindex msvr4-struct-return
+Return structures smaller than 8 bytes in registers (as specified by the
+SVR4 ABI)@.
-@item -mcpu=@var{cpu_type}
-@opindex mcpu
-Set the instruction set, register set, and instruction scheduling
-parameters for machine type @var{cpu_type}. Supported values for
-@var{cpu_type} are @samp{c30}, @samp{c31}, @samp{c32}, @samp{c40}, and
-@samp{c44}. The default is @samp{c40} to generate code for the
-TMS320C40.
+@item -mabi=@var{abi-type}
+@opindex mabi
+Extend the current ABI with a particular extension, or remove such extension.
+Valid values are @var{altivec}, @var{no-altivec}, @var{spe},
+@var{no-spe}, @var{ibmlongdouble}, @var{ieeelongdouble}@.
-@item -mbig-memory
-@item -mbig
-@itemx -msmall-memory
-@itemx -msmall
-@opindex mbig-memory
-@opindex mbig
-@opindex msmall-memory
-@opindex msmall
-Generates code for the big or small memory model. The small memory
-model assumed that all data fits into one 64K word page. At run-time
-the data page (DP) register must be set to point to the 64K page
-containing the .bss and .data program sections. The big memory model is
-the default and requires reloading of the DP register for every direct
-memory access.
-
-@item -mbk
-@itemx -mno-bk
-@opindex mbk
-@opindex mno-bk
-Allow (disallow) allocation of general integer operands into the block
-count register BK@.
-
-@item -mdb
-@itemx -mno-db
-@opindex mdb
-@opindex mno-db
-Enable (disable) generation of code using decrement and branch,
-DBcond(D), instructions. This is enabled by default for the C4x. To be
-on the safe side, this is disabled for the C3x, since the maximum
-iteration count on the C3x is @math{2^{23} + 1} (but who iterates loops more than
-@math{2^{23}} times on the C3x?). Note that GCC will try to reverse a loop so
-that it can utilise the decrement and branch instruction, but will give
-up if there is more than one memory reference in the loop. Thus a loop
-where the loop counter is decremented can generate slightly more
-efficient code, in cases where the RPTB instruction cannot be utilised.
-
-@item -mdp-isr-reload
-@itemx -mparanoid
-@opindex mdp-isr-reload
-@opindex mparanoid
-Force the DP register to be saved on entry to an interrupt service
-routine (ISR), reloaded to point to the data section, and restored on
-exit from the ISR@. This should not be required unless someone has
-violated the small memory model by modifying the DP register, say within
-an object library.
-
-@item -mmpyi
-@itemx -mno-mpyi
-@opindex mmpyi
-@opindex mno-mpyi
-For the C3x use the 24-bit MPYI instruction for integer multiplies
-instead of a library call to guarantee 32-bit results. Note that if one
-of the operands is a constant, then the multiplication will be performed
-using shifts and adds. If the @option{-mmpyi} option is not specified for the C3x,
-then squaring operations are performed inline instead of a library call.
-
-@item -mfast-fix
-@itemx -mno-fast-fix
-@opindex mfast-fix
-@opindex mno-fast-fix
-The C3x/C4x FIX instruction to convert a floating point value to an
-integer value chooses the nearest integer less than or equal to the
-floating point value rather than to the nearest integer. Thus if the
-floating point number is negative, the result will be incorrectly
-truncated an additional code is necessary to detect and correct this
-case. This option can be used to disable generation of the additional
-code required to correct the result.
-
-@item -mrptb
-@itemx -mno-rptb
-@opindex mrptb
-@opindex mno-rptb
-Enable (disable) generation of repeat block sequences using the RPTB
-instruction for zero overhead looping. The RPTB construct is only used
-for innermost loops that do not call functions or jump across the loop
-boundaries. There is no advantage having nested RPTB loops due to the
-overhead required to save and restore the RC, RS, and RE registers.
-This is enabled by default with @option{-O2}.
-
-@item -mrpts=@var{count}
-@itemx -mno-rpts
-@opindex mrpts
-@opindex mno-rpts
-Enable (disable) the use of the single instruction repeat instruction
-RPTS@. If a repeat block contains a single instruction, and the loop
-count can be guaranteed to be less than the value @var{count}, GCC will
-emit a RPTS instruction instead of a RPTB@. If no value is specified,
-then a RPTS will be emitted even if the loop count cannot be determined
-at compile time. Note that the repeated instruction following RPTS does
-not have to be reloaded from memory each iteration, thus freeing up the
-CPU buses for operands. However, since interrupts are blocked by this
-instruction, it is disabled by default.
-
-@item -mloop-unsigned
-@itemx -mno-loop-unsigned
-@opindex mloop-unsigned
-@opindex mno-loop-unsigned
-The maximum iteration count when using RPTS and RPTB (and DB on the C40)
-is @math{2^{31} + 1} since these instructions test if the iteration count is
-negative to terminate the loop. If the iteration count is unsigned
-there is a possibility than the @math{2^{31} + 1} maximum iteration count may be
-exceeded. This switch allows an unsigned iteration count.
-
-@item -mti
-@opindex mti
-Try to emit an assembler syntax that the TI assembler (asm30) is happy
-with. This also enforces compatibility with the API employed by the TI
-C3x C compiler. For example, long doubles are passed as structures
-rather than in floating point registers.
-
-@item -mregparm
-@itemx -mmemparm
-@opindex mregparm
-@opindex mmemparm
-Generate code that uses registers (stack) for passing arguments to functions.
-By default, arguments are passed in registers where possible rather
-than by pushing arguments on to the stack.
-
-@item -mparallel-insns
-@itemx -mno-parallel-insns
-@opindex mparallel-insns
-@opindex mno-parallel-insns
-Allow the generation of parallel instructions. This is enabled by
-default with @option{-O2}.
-
-@item -mparallel-mpy
-@itemx -mno-parallel-mpy
-@opindex mparallel-mpy
-@opindex mno-parallel-mpy
-Allow the generation of MPY||ADD and MPY||SUB parallel instructions,
-provided @option{-mparallel-insns} is also specified. These instructions have
-tight register constraints which can pessimize the code generation
-of large functions.
+@item -mabi=spe
+@opindex mabi=spe
+Extend the current ABI with SPE ABI extensions. This does not change
+the default ABI, instead it adds the SPE ABI extensions to the current
+ABI@.
-@end table
+@item -mabi=no-spe
+@opindex mabi=no-spe
+Disable Booke SPE ABI extensions for the current ABI@.
-@node V850 Options
-@subsection V850 Options
-@cindex V850 Options
+@item -mabi=ibmlongdouble
+@opindex mabi=ibmlongdouble
+Change the current ABI to use IBM extended precision long double.
+This is a PowerPC 32-bit SYSV ABI option.
-These @samp{-m} options are defined for V850 implementations:
+@item -mabi=ieeelongdouble
+@opindex mabi=ieeelongdouble
+Change the current ABI to use IEEE extended precision long double.
+This is a PowerPC 32-bit Linux ABI option.
-@table @gcctabopt
-@item -mlong-calls
-@itemx -mno-long-calls
-@opindex mlong-calls
-@opindex mno-long-calls
-Treat all calls as being far away (near). If calls are assumed to be
-far away, the compiler will always load the functions address up into a
-register, and call indirect through the pointer.
+@item -mprototype
+@itemx -mno-prototype
+@opindex mprototype
+@opindex mno-prototype
+On System V.4 and embedded PowerPC systems assume that all calls to
+variable argument functions are properly prototyped. Otherwise, the
+compiler must insert an instruction before every non prototyped call to
+set or clear bit 6 of the condition code register (@var{CR}) to
+indicate whether floating point values were passed in the floating point
+registers in case the function takes a variable arguments. With
+@option{-mprototype}, only calls to prototyped variable argument functions
+will set or clear the bit.
-@item -mno-ep
-@itemx -mep
-@opindex mno-ep
-@opindex mep
-Do not optimize (do optimize) basic blocks that use the same index
-pointer 4 or more times to copy pointer into the @code{ep} register, and
-use the shorter @code{sld} and @code{sst} instructions. The @option{-mep}
-option is on by default if you optimize.
+@item -msim
+@opindex msim
+On embedded PowerPC systems, assume that the startup module is called
+@file{sim-crt0.o} and that the standard C libraries are @file{libsim.a} and
+@file{libc.a}. This is the default for @samp{powerpc-*-eabisim}
+configurations.
-@item -mno-prolog-function
-@itemx -mprolog-function
-@opindex mno-prolog-function
-@opindex mprolog-function
-Do not use (do use) external functions to save and restore registers at
-the prolog and epilog of a function. The external functions are slower,
-but use less code space if more than one function saves the same number
-of registers. The @option{-mprolog-function} option is on by default if
-you optimize.
+@item -mmvme
+@opindex mmvme
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libmvme.a} and
+@file{libc.a}.
-@item -mspace
-@opindex mspace
-Try to make the code as small as possible. At present, this just turns
-on the @option{-mep} and @option{-mprolog-function} options.
+@item -mads
+@opindex mads
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libads.a} and
+@file{libc.a}.
-@item -mtda=@var{n}
-@opindex mtda
-Put static or global variables whose size is @var{n} bytes or less into
-the tiny data area that register @code{ep} points to. The tiny data
-area can hold up to 256 bytes in total (128 bytes for byte references).
+@item -myellowknife
+@opindex myellowknife
+On embedded PowerPC systems, assume that the startup module is called
+@file{crt0.o} and the standard C libraries are @file{libyk.a} and
+@file{libc.a}.
-@item -msda=@var{n}
-@opindex msda
-Put static or global variables whose size is @var{n} bytes or less into
-the small data area that register @code{gp} points to. The small data
-area can hold up to 64 kilobytes.
+@item -mvxworks
+@opindex mvxworks
+On System V.4 and embedded PowerPC systems, specify that you are
+compiling for a VxWorks system.
-@item -mzda=@var{n}
-@opindex mzda
-Put static or global variables whose size is @var{n} bytes or less into
-the first 32 kilobytes of memory.
+@item -memb
+@opindex memb
+On embedded PowerPC systems, set the @var{PPC_EMB} bit in the ELF flags
+header to indicate that @samp{eabi} extended relocations are used.
-@item -mv850
-@opindex mv850
-Specify that the target processor is the V850.
+@item -meabi
+@itemx -mno-eabi
+@opindex meabi
+@opindex mno-eabi
+On System V.4 and embedded PowerPC systems do (do not) adhere to the
+Embedded Applications Binary Interface (eabi) which is a set of
+modifications to the System V.4 specifications. Selecting @option{-meabi}
+means that the stack is aligned to an 8 byte boundary, a function
+@code{__eabi} is called to from @code{main} to set up the eabi
+environment, and the @option{-msdata} option can use both @code{r2} and
+@code{r13} to point to two separate small data areas. Selecting
+@option{-mno-eabi} means that the stack is aligned to a 16 byte boundary,
+do not call an initialization function from @code{main}, and the
+@option{-msdata} option will only use @code{r13} to point to a single
+small data area. The @option{-meabi} option is on by default if you
+configured GCC using one of the @samp{powerpc*-*-eabi*} options.
-@item -mbig-switch
-@opindex mbig-switch
-Generate code suitable for big switch tables. Use this option only if
-the assembler/linker complain about out of range branches within a switch
-table.
-@end table
+@item -msdata=eabi
+@opindex msdata=eabi
+On System V.4 and embedded PowerPC systems, put small initialized
+@code{const} global and static data in the @samp{.sdata2} section, which
+is pointed to by register @code{r2}. Put small initialized
+non-@code{const} global and static data in the @samp{.sdata} section,
+which is pointed to by register @code{r13}. Put small uninitialized
+global and static data in the @samp{.sbss} section, which is adjacent to
+the @samp{.sdata} section. The @option{-msdata=eabi} option is
+incompatible with the @option{-mrelocatable} option. The
+@option{-msdata=eabi} option also sets the @option{-memb} option.
-@node ARC Options
-@subsection ARC Options
-@cindex ARC Options
+@item -msdata=sysv
+@opindex msdata=sysv
+On System V.4 and embedded PowerPC systems, put small global and static
+data in the @samp{.sdata} section, which is pointed to by register
+@code{r13}. Put small uninitialized global and static data in the
+@samp{.sbss} section, which is adjacent to the @samp{.sdata} section.
+The @option{-msdata=sysv} option is incompatible with the
+@option{-mrelocatable} option.
+
+@item -msdata=default
+@itemx -msdata
+@opindex msdata=default
+@opindex msdata
+On System V.4 and embedded PowerPC systems, if @option{-meabi} is used,
+compile code the same as @option{-msdata=eabi}, otherwise compile code the
+same as @option{-msdata=sysv}.
-These options are defined for ARC implementations:
+@item -msdata=data
+@opindex msdata=data
+On System V.4 and embedded PowerPC systems, put small global
+data in the @samp{.sdata} section. Put small uninitialized global
+data in the @samp{.sbss} section. Do not use register @code{r13}
+to address small data however. This is the default behavior unless
+other @option{-msdata} options are used.
-@table @gcctabopt
-@item -EL
-@opindex EL
-Compile code for little endian mode. This is the default.
+@item -msdata=none
+@itemx -mno-sdata
+@opindex msdata=none
+@opindex mno-sdata
+On embedded PowerPC systems, put all initialized global and static data
+in the @samp{.data} section, and all uninitialized data in the
+@samp{.bss} section.
-@item -EB
-@opindex EB
-Compile code for big endian mode.
+@item -G @var{num}
+@opindex G
+@cindex smaller data references (PowerPC)
+@cindex .sdata/.sdata2 references (PowerPC)
+On embedded PowerPC systems, put global and static items less than or
+equal to @var{num} bytes into the small data or bss sections instead of
+the normal data or bss section. By default, @var{num} is 8. The
+@option{-G @var{num}} switch is also passed to the linker.
+All modules should be compiled with the same @option{-G @var{num}} value.
-@item -mmangle-cpu
-@opindex mmangle-cpu
-Prepend the name of the cpu to all public symbol names.
-In multiple-processor systems, there are many ARC variants with different
-instruction and register set characteristics. This flag prevents code
-compiled for one cpu to be linked with code compiled for another.
-No facility exists for handling variants that are ``almost identical''.
-This is an all or nothing option.
+@item -mregnames
+@itemx -mno-regnames
+@opindex mregnames
+@opindex mno-regnames
+On System V.4 and embedded PowerPC systems do (do not) emit register
+names in the assembly language output using symbolic forms.
-@item -mcpu=@var{cpu}
-@opindex mcpu
-Compile code for ARC variant @var{cpu}.
-Which variants are supported depend on the configuration.
-All variants support @option{-mcpu=base}, this is the default.
+@item -mlongcall
+@itemx -mno-longcall
+@opindex mlongcall
+@opindex mno-longcall
+By default assume that all calls are far away so that a longer more
+expensive calling sequence is required. This is required for calls
+further than 32 megabytes (33,554,432 bytes) from the current location.
+A short call will be generated if the compiler knows
+the call cannot be that far away. This setting can be overridden by
+the @code{shortcall} function attribute, or by @code{#pragma
+longcall(0)}.
+
+Some linkers are capable of detecting out-of-range calls and generating
+glue code on the fly. On these systems, long calls are unnecessary and
+generate slower code. As of this writing, the AIX linker can do this,
+as can the GNU linker for PowerPC/64. It is planned to add this feature
+to the GNU linker for 32-bit PowerPC systems as well.
+
+On Darwin/PPC systems, @code{#pragma longcall} will generate ``jbsr
+callee, L42'', plus a ``branch island'' (glue code). The two target
+addresses represent the callee and the ``branch island''. The
+Darwin/PPC linker will prefer the first address and generate a ``bl
+callee'' if the PPC ``bl'' instruction will reach the callee directly;
+otherwise, the linker will generate ``bl L42'' to call the ``branch
+island''. The ``branch island'' is appended to the body of the
+calling function; it computes the full 32-bit address of the callee
+and jumps to it.
+
+On Mach-O (Darwin) systems, this option directs the compiler emit to
+the glue for every direct call, and the Darwin linker decides whether
+to use or discard it.
+
+In the future, we may cause GCC to ignore all longcall specifications
+when the linker is known to generate glue.
-@item -mtext=@var{text-section}
-@itemx -mdata=@var{data-section}
-@itemx -mrodata=@var{readonly-data-section}
-@opindex mtext
-@opindex mdata
-@opindex mrodata
-Put functions, data, and readonly data in @var{text-section},
-@var{data-section}, and @var{readonly-data-section} respectively
-by default. This can be overridden with the @code{section} attribute.
-@xref{Variable Attributes}.
+@item -pthread
+@opindex pthread
+Adds support for multithreading with the @dfn{pthreads} library.
+This option sets flags for both the preprocessor and linker.
@end table
-@node NS32K Options
-@subsection NS32K Options
-@cindex NS32K options
+@node S/390 and zSeries Options
+@subsection S/390 and zSeries Options
+@cindex S/390 and zSeries Options
-These are the @samp{-m} options defined for the 32000 series. The default
-values for these options depends on which style of 32000 was selected when
-the compiler was configured; the defaults for the most common choices are
-given below.
+These are the @samp{-m} options defined for the S/390 and zSeries architecture.
@table @gcctabopt
-@item -m32032
-@itemx -m32032
-@opindex m32032
-@opindex m32032
-Generate output for a 32032. This is the default
-when the compiler is configured for 32032 and 32016 based systems.
-
-@item -m32332
-@itemx -m32332
-@opindex m32332
-@opindex m32332
-Generate output for a 32332. This is the default
-when the compiler is configured for 32332-based systems.
-
-@item -m32532
-@itemx -m32532
-@opindex m32532
-@opindex m32532
-Generate output for a 32532. This is the default
-when the compiler is configured for 32532-based systems.
-
-@item -m32081
-@opindex m32081
-Generate output containing 32081 instructions for floating point.
-This is the default for all systems.
-
-@item -m32381
-@opindex m32381
-Generate output containing 32381 instructions for floating point. This
-also implies @option{-m32081}. The 32381 is only compatible with the 32332
-and 32532 cpus. This is the default for the pc532-netbsd configuration.
-
-@item -mmulti-add
-@opindex mmulti-add
-Try and generate multiply-add floating point instructions @code{polyF}
-and @code{dotF}. This option is only available if the @option{-m32381}
-option is in effect. Using these instructions requires changes to
-register allocation which generally has a negative impact on
-performance. This option should only be enabled when compiling code
-particularly likely to make heavy use of multiply-add instructions.
-
-@item -mnomulti-add
-@opindex mnomulti-add
-Do not try and generate multiply-add floating point instructions
-@code{polyF} and @code{dotF}. This is the default on all platforms.
-
-@item -msoft-float
+@item -mhard-float
+@itemx -msoft-float
+@opindex mhard-float
@opindex msoft-float
-Generate output containing library calls for floating point.
-@strong{Warning:} the requisite libraries may not be available.
-
-@item -mnobitfield
-@opindex mnobitfield
-Do not use the bit-field instructions. On some machines it is faster to
-use shifting and masking operations. This is the default for the pc532.
-
-@item -mbitfield
-@opindex mbitfield
-Do use the bit-field instructions. This is the default for all platforms
-except the pc532.
-
-@item -mrtd
-@opindex mrtd
-Use a different function-calling convention, in which functions
-that take a fixed number of arguments return pop their
-arguments on return with the @code{ret} instruction.
-
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
-
-Also, you must provide function prototypes for all functions that
-take variable numbers of arguments (including @code{printf});
-otherwise incorrect code will be generated for calls to those
-functions.
-
-In addition, seriously incorrect code will result if you call a
-function with too many arguments. (Normally, extra arguments are
-harmlessly ignored.)
+Use (do not use) the hardware floating-point instructions and registers
+for floating-point operations. When @option{-msoft-float} is specified,
+functions in @file{libgcc.a} will be used to perform floating-point
+operations. When @option{-mhard-float} is specified, the compiler
+generates IEEE floating-point instructions. This is the default.
-This option takes its name from the 680x0 @code{rtd} instruction.
+@item -mhard-dfp
+@itemx -mno-hard-dfp
+@opindex mhard-dfp
+@opindex mno-hard-dfp
+Use (do not use) the hardware decimal-floating-point instructions for
+decimal-floating-point operations. When @option{-mno-hard-dfp} is
+specified, functions in @file{libgcc.a} will be used to perform
+decimal-floating-point operations. When @option{-mhard-dfp} is
+specified, the compiler generates decimal-floating-point hardware
+instructions. This is the default for @option{-march=z9-ec} or higher.
+@item -mlong-double-64
+@itemx -mlong-double-128
+@opindex mlong-double-64
+@opindex mlong-double-128
+These switches control the size of @code{long double} type. A size
+of 64bit makes the @code{long double} type equivalent to the @code{double}
+type. This is the default.
-@item -mregparam
-@opindex mregparam
-Use a different function-calling convention where the first two arguments
-are passed in registers.
+@item -mbackchain
+@itemx -mno-backchain
+@opindex mbackchain
+@opindex mno-backchain
+Store (do not store) the address of the caller's frame as backchain pointer
+into the callee's stack frame.
+A backchain may be needed to allow debugging using tools that do not understand
+DWARF-2 call frame information.
+When @option{-mno-packed-stack} is in effect, the backchain pointer is stored
+at the bottom of the stack frame; when @option{-mpacked-stack} is in effect,
+the backchain is placed into the topmost word of the 96/160 byte register
+save area.
+
+In general, code compiled with @option{-mbackchain} is call-compatible with
+code compiled with @option{-mmo-backchain}; however, use of the backchain
+for debugging purposes usually requires that the whole binary is built with
+@option{-mbackchain}. Note that the combination of @option{-mbackchain},
+@option{-mpacked-stack} and @option{-mhard-float} is not supported. In order
+to build a linux kernel use @option{-msoft-float}.
+
+The default is to not maintain the backchain.
+
+@item -mpacked-stack
+@itemx -mno-packed-stack
+@opindex mpacked-stack
+@opindex mno-packed-stack
+Use (do not use) the packed stack layout. When @option{-mno-packed-stack} is
+specified, the compiler uses the all fields of the 96/160 byte register save
+area only for their default purpose; unused fields still take up stack space.
+When @option{-mpacked-stack} is specified, register save slots are densely
+packed at the top of the register save area; unused space is reused for other
+purposes, allowing for more efficient use of the available stack space.
+However, when @option{-mbackchain} is also in effect, the topmost word of
+the save area is always used to store the backchain, and the return address
+register is always saved two words below the backchain.
+
+As long as the stack frame backchain is not used, code generated with
+@option{-mpacked-stack} is call-compatible with code generated with
+@option{-mno-packed-stack}. Note that some non-FSF releases of GCC 2.95 for
+S/390 or zSeries generated code that uses the stack frame backchain at run
+time, not just for debugging purposes. Such code is not call-compatible
+with code compiled with @option{-mpacked-stack}. Also, note that the
+combination of @option{-mbackchain},
+@option{-mpacked-stack} and @option{-mhard-float} is not supported. In order
+to build a linux kernel use @option{-msoft-float}.
+
+The default is to not use the packed stack layout.
-This calling convention is incompatible with the one normally
-used on Unix, so you cannot use it if you need to call libraries
-compiled with the Unix compiler.
+@item -msmall-exec
+@itemx -mno-small-exec
+@opindex msmall-exec
+@opindex mno-small-exec
+Generate (or do not generate) code using the @code{bras} instruction
+to do subroutine calls.
+This only works reliably if the total executable size does not
+exceed 64k. The default is to use the @code{basr} instruction instead,
+which does not have this limitation.
-@item -mnoregparam
-@opindex mnoregparam
-Do not pass any arguments in registers. This is the default for all
-targets.
+@item -m64
+@itemx -m31
+@opindex m64
+@opindex m31
+When @option{-m31} is specified, generate code compliant to the
+GNU/Linux for S/390 ABI@. When @option{-m64} is specified, generate
+code compliant to the GNU/Linux for zSeries ABI@. This allows GCC in
+particular to generate 64-bit instructions. For the @samp{s390}
+targets, the default is @option{-m31}, while the @samp{s390x}
+targets default to @option{-m64}.
-@item -msb
-@opindex msb
-It is OK to use the sb as an index register which is always loaded with
-zero. This is the default for the pc532-netbsd target.
+@item -mzarch
+@itemx -mesa
+@opindex mzarch
+@opindex mesa
+When @option{-mzarch} is specified, generate code using the
+instructions available on z/Architecture.
+When @option{-mesa} is specified, generate code using the
+instructions available on ESA/390. Note that @option{-mesa} is
+not possible with @option{-m64}.
+When generating code compliant to the GNU/Linux for S/390 ABI,
+the default is @option{-mesa}. When generating code compliant
+to the GNU/Linux for zSeries ABI, the default is @option{-mzarch}.
-@item -mnosb
-@opindex mnosb
-The sb register is not available for use or has not been initialized to
-zero by the run time system. This is the default for all targets except
-the pc532-netbsd. It is also implied whenever @option{-mhimem} or
-@option{-fpic} is set.
+@item -mmvcle
+@itemx -mno-mvcle
+@opindex mmvcle
+@opindex mno-mvcle
+Generate (or do not generate) code using the @code{mvcle} instruction
+to perform block moves. When @option{-mno-mvcle} is specified,
+use a @code{mvc} loop instead. This is the default unless optimizing for
+size.
-@item -mhimem
-@opindex mhimem
-Many ns32000 series addressing modes use displacements of up to 512MB@.
-If an address is above 512MB then displacements from zero can not be used.
-This option causes code to be generated which can be loaded above 512MB@.
-This may be useful for operating systems or ROM code.
+@item -mdebug
+@itemx -mno-debug
+@opindex mdebug
+@opindex mno-debug
+Print (or do not print) additional debug information when compiling.
+The default is to not print debug information.
-@item -mnohimem
-@opindex mnohimem
-Assume code will be loaded in the first 512MB of virtual address space.
-This is the default for all platforms.
+@item -march=@var{cpu-type}
+@opindex march
+Generate code that will run on @var{cpu-type}, which is the name of a system
+representing a certain processor type. Possible values for
+@var{cpu-type} are @samp{g5}, @samp{g6}, @samp{z900}, @samp{z990},
+@samp{z9-109}, @samp{z9-ec} and @samp{z10}.
+When generating code using the instructions available on z/Architecture,
+the default is @option{-march=z900}. Otherwise, the default is
+@option{-march=g5}.
+@item -mtune=@var{cpu-type}
+@opindex mtune
+Tune to @var{cpu-type} everything applicable about the generated code,
+except for the ABI and the set of available instructions.
+The list of @var{cpu-type} values is the same as for @option{-march}.
+The default is the value used for @option{-march}.
+
+@item -mtpf-trace
+@itemx -mno-tpf-trace
+@opindex mtpf-trace
+@opindex mno-tpf-trace
+Generate code that adds (does not add) in TPF OS specific branches to trace
+routines in the operating system. This option is off by default, even
+when compiling for the TPF OS@.
+@item -mfused-madd
+@itemx -mno-fused-madd
+@opindex mfused-madd
+@opindex mno-fused-madd
+Generate code that uses (does not use) the floating point multiply and
+accumulate instructions. These instructions are generated by default if
+hardware floating point is used.
+
+@item -mwarn-framesize=@var{framesize}
+@opindex mwarn-framesize
+Emit a warning if the current function exceeds the given frame size. Because
+this is a compile time check it doesn't need to be a real problem when the program
+runs. It is intended to identify functions which most probably cause
+a stack overflow. It is useful to be used in an environment with limited stack
+size e.g.@: the linux kernel.
+
+@item -mwarn-dynamicstack
+@opindex mwarn-dynamicstack
+Emit a warning if the function calls alloca or uses dynamically
+sized arrays. This is generally a bad idea with a limited stack size.
+
+@item -mstack-guard=@var{stack-guard}
+@itemx -mstack-size=@var{stack-size}
+@opindex mstack-guard
+@opindex mstack-size
+If these options are provided the s390 back end emits additional instructions in
+the function prologue which trigger a trap if the stack size is @var{stack-guard}
+bytes above the @var{stack-size} (remember that the stack on s390 grows downward).
+If the @var{stack-guard} option is omitted the smallest power of 2 larger than
+the frame size of the compiled function is chosen.
+These options are intended to be used to help debugging stack overflow problems.
+The additionally emitted code causes only little overhead and hence can also be
+used in production like systems without greater performance degradation. The given
+values have to be exact powers of 2 and @var{stack-size} has to be greater than
+@var{stack-guard} without exceeding 64k.
+In order to be efficient the extra code makes the assumption that the stack starts
+at an address aligned to the value given by @var{stack-size}.
+The @var{stack-guard} option can only be used in conjunction with @var{stack-size}.
@end table
-@node AVR Options
-@subsection AVR Options
-@cindex AVR Options
+@node Score Options
+@subsection Score Options
+@cindex Score Options
-These options are defined for AVR implementations:
+These options are defined for Score implementations:
@table @gcctabopt
-@item -mmcu=@var{mcu}
-@opindex mmcu
-Specify ATMEL AVR instruction set or MCU type.
+@item -meb
+@opindex meb
+Compile code for big endian mode. This is the default.
-Instruction set avr1 is for the minimal AVR core, not supported by the C
-compiler, only for assembler programs (MCU types: at90s1200, attiny10,
-attiny11, attiny12, attiny15, attiny28).
+@item -mel
+@opindex mel
+Compile code for little endian mode.
-Instruction set avr2 (default) is for the classic AVR core with up to
-8K program memory space (MCU types: at90s2313, at90s2323, attiny22,
-at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515,
-at90c8534, at90s8535).
+@item -mnhwloop
+@opindex mnhwloop
+Disable generate bcnz instruction.
-Instruction set avr3 is for the classic AVR core with up to 128K program
-memory space (MCU types: atmega103, atmega603, at43usb320, at76c711).
+@item -muls
+@opindex muls
+Enable generate unaligned load and store instruction.
-Instruction set avr4 is for the enhanced AVR core with up to 8K program
-memory space (MCU types: atmega8, atmega83, atmega85).
+@item -mmac
+@opindex mmac
+Enable the use of multiply-accumulate instructions. Disabled by default.
-Instruction set avr5 is for the enhanced AVR core with up to 128K program
-memory space (MCU types: atmega16, atmega161, atmega163, atmega32, atmega323,
-atmega64, atmega128, at43usb355, at94k).
+@item -mscore5
+@opindex mscore5
+Specify the SCORE5 as the target architecture.
-@item -msize
-@opindex msize
-Output instruction sizes to the asm file.
+@item -mscore5u
+@opindex mscore5u
+Specify the SCORE5U of the target architecture.
-@item -minit-stack=@var{N}
-@opindex minit-stack
-Specify the initial stack address, which may be a symbol or numeric value,
-@samp{__stack} is the default.
+@item -mscore7
+@opindex mscore7
+Specify the SCORE7 as the target architecture. This is the default.
-@item -mno-interrupts
-@opindex mno-interrupts
-Generated code is not compatible with hardware interrupts.
-Code size will be smaller.
+@item -mscore7d
+@opindex mscore7d
+Specify the SCORE7D as the target architecture.
+@end table
-@item -mcall-prologues
-@opindex mcall-prologues
-Functions prologues/epilogues expanded as call to appropriate
-subroutines. Code size will be smaller.
+@node SH Options
+@subsection SH Options
-@item -mno-tablejump
-@opindex mno-tablejump
-Do not generate tablejump insns which sometimes increase code size.
+These @samp{-m} options are defined for the SH implementations:
-@item -mtiny-stack
-@opindex mtiny-stack
-Change only the low 8 bits of the stack pointer.
-@end table
+@table @gcctabopt
+@item -m1
+@opindex m1
+Generate code for the SH1.
-@node MCore Options
-@subsection MCore Options
-@cindex MCore options
+@item -m2
+@opindex m2
+Generate code for the SH2.
-These are the @samp{-m} options defined for the Motorola M*Core
-processors.
+@item -m2e
+Generate code for the SH2e.
-@table @gcctabopt
+@item -m3
+@opindex m3
+Generate code for the SH3.
-@item -mhardlit
-@itemx -mhardlit
-@itemx -mno-hardlit
-@opindex mhardlit
-@opindex mhardlit
-@opindex mno-hardlit
-Inline constants into the code stream if it can be done in two
-instructions or less.
+@item -m3e
+@opindex m3e
+Generate code for the SH3e.
-@item -mdiv
-@itemx -mdiv
-@itemx -mno-div
-@opindex mdiv
-@opindex mdiv
-@opindex mno-div
-Use the divide instruction. (Enabled by default).
+@item -m4-nofpu
+@opindex m4-nofpu
+Generate code for the SH4 without a floating-point unit.
-@item -mrelax-immediate
-@itemx -mrelax-immediate
-@itemx -mno-relax-immediate
-@opindex mrelax-immediate
-@opindex mrelax-immediate
-@opindex mno-relax-immediate
-Allow arbitrary sized immediates in bit operations.
+@item -m4-single-only
+@opindex m4-single-only
+Generate code for the SH4 with a floating-point unit that only
+supports single-precision arithmetic.
-@item -mwide-bitfields
-@itemx -mwide-bitfields
-@itemx -mno-wide-bitfields
-@opindex mwide-bitfields
-@opindex mwide-bitfields
-@opindex mno-wide-bitfields
-Always treat bit-fields as int-sized.
+@item -m4-single
+@opindex m4-single
+Generate code for the SH4 assuming the floating-point unit is in
+single-precision mode by default.
-@item -m4byte-functions
-@itemx -m4byte-functions
-@itemx -mno-4byte-functions
-@opindex m4byte-functions
-@opindex m4byte-functions
-@opindex mno-4byte-functions
-Force all functions to be aligned to a four byte boundary.
+@item -m4
+@opindex m4
+Generate code for the SH4.
+
+@item -m4a-nofpu
+@opindex m4a-nofpu
+Generate code for the SH4al-dsp, or for a SH4a in such a way that the
+floating-point unit is not used.
+
+@item -m4a-single-only
+@opindex m4a-single-only
+Generate code for the SH4a, in such a way that no double-precision
+floating point operations are used.
-@item -mcallgraph-data
-@itemx -mcallgraph-data
-@itemx -mno-callgraph-data
-@opindex mcallgraph-data
-@opindex mcallgraph-data
-@opindex mno-callgraph-data
-Emit callgraph information.
+@item -m4a-single
+@opindex m4a-single
+Generate code for the SH4a assuming the floating-point unit is in
+single-precision mode by default.
-@item -mslow-bytes
-@itemx -mslow-bytes
-@itemx -mno-slow-bytes
-@opindex mslow-bytes
-@opindex mslow-bytes
-@opindex mno-slow-bytes
-Prefer word access when reading byte quantities.
+@item -m4a
+@opindex m4a
+Generate code for the SH4a.
-@item -mlittle-endian
-@itemx -mlittle-endian
-@itemx -mbig-endian
-@opindex mlittle-endian
-@opindex mlittle-endian
-@opindex mbig-endian
-Generate code for a little endian target.
+@item -m4al
+@opindex m4al
+Same as @option{-m4a-nofpu}, except that it implicitly passes
+@option{-dsp} to the assembler. GCC doesn't generate any DSP
+instructions at the moment.
-@item -m210
-@itemx -m210
-@itemx -m340
-@opindex m210
-@opindex m210
-@opindex m340
-Generate code for the 210 processor.
-@end table
+@item -mb
+@opindex mb
+Compile code for the processor in big endian mode.
-@node IA-64 Options
-@subsection IA-64 Options
-@cindex IA-64 Options
+@item -ml
+@opindex ml
+Compile code for the processor in little endian mode.
-These are the @samp{-m} options defined for the Intel IA-64 architecture.
+@item -mdalign
+@opindex mdalign
+Align doubles at 64-bit boundaries. Note that this changes the calling
+conventions, and thus some functions from the standard C library will
+not work unless you recompile it first with @option{-mdalign}.
-@table @gcctabopt
-@item -mbig-endian
-@opindex mbig-endian
-Generate code for a big endian target. This is the default for HPUX@.
+@item -mrelax
+@opindex mrelax
+Shorten some address references at link time, when possible; uses the
+linker option @option{-relax}.
-@item -mlittle-endian
-@opindex mlittle-endian
-Generate code for a little endian target. This is the default for AIX5
-and Linux.
+@item -mbigtable
+@opindex mbigtable
+Use 32-bit offsets in @code{switch} tables. The default is to use
+16-bit offsets.
-@item -mgnu-as
-@itemx -mno-gnu-as
-@opindex mgnu-as
-@opindex mno-gnu-as
-Generate (or don't) code for the GNU assembler. This is the default.
-@c Also, this is the default if the configure option @option{--with-gnu-as}
-@c is used.
+@item -mbitops
+@opindex mbitops
+Enable the use of bit manipulation instructions on SH2A.
-@item -mgnu-ld
-@itemx -mno-gnu-ld
-@opindex mgnu-ld
-@opindex mno-gnu-ld
-Generate (or don't) code for the GNU linker. This is the default.
-@c Also, this is the default if the configure option @option{--with-gnu-ld}
-@c is used.
+@item -mfmovd
+@opindex mfmovd
+Enable the use of the instruction @code{fmovd}.
-@item -mno-pic
-@opindex mno-pic
-Generate code that does not use a global pointer register. The result
-is not position independent code, and violates the IA-64 ABI@.
+@item -mhitachi
+@opindex mhitachi
+Comply with the calling conventions defined by Renesas.
-@item -mvolatile-asm-stop
-@itemx -mno-volatile-asm-stop
-@opindex mvolatile-asm-stop
-@opindex mno-volatile-asm-stop
-Generate (or don't) a stop bit immediately before and after volatile asm
-statements.
+@item -mrenesas
+@opindex mhitachi
+Comply with the calling conventions defined by Renesas.
-@item -mb-step
-@opindex mb-step
-Generate code that works around Itanium B step errata.
+@item -mno-renesas
+@opindex mhitachi
+Comply with the calling conventions defined for GCC before the Renesas
+conventions were available. This option is the default for all
+targets of the SH toolchain except for @samp{sh-symbianelf}.
-@item -mregister-names
-@itemx -mno-register-names
-@opindex mregister-names
-@opindex mno-register-names
-Generate (or don't) @samp{in}, @samp{loc}, and @samp{out} register names for
-the stacked registers. This may make assembler output more readable.
+@item -mnomacsave
+@opindex mnomacsave
+Mark the @code{MAC} register as call-clobbered, even if
+@option{-mhitachi} is given.
-@item -mno-sdata
-@itemx -msdata
-@opindex mno-sdata
-@opindex msdata
-Disable (or enable) optimizations that use the small data section. This may
-be useful for working around optimizer bugs.
+@item -mieee
+@opindex mieee
+Increase IEEE-compliance of floating-point code.
+At the moment, this is equivalent to @option{-fno-finite-math-only}.
+When generating 16 bit SH opcodes, getting IEEE-conforming results for
+comparisons of NANs / infinities incurs extra overhead in every
+floating point comparison, therefore the default is set to
+@option{-ffinite-math-only}.
+
+@item -minline-ic_invalidate
+@opindex minline-ic_invalidate
+Inline code to invalidate instruction cache entries after setting up
+nested function trampolines.
+This option has no effect if -musermode is in effect and the selected
+code generation option (e.g. -m4) does not allow the use of the icbi
+instruction.
+If the selected code generation option does not allow the use of the icbi
+instruction, and -musermode is not in effect, the inlined code will
+manipulate the instruction cache address array directly with an associative
+write. This not only requires privileged mode, but it will also
+fail if the cache line had been mapped via the TLB and has become unmapped.
-@item -mconstant-gp
-@opindex mconstant-gp
-Generate code that uses a single constant global pointer value. This is
-useful when compiling kernel code.
+@item -misize
+@opindex misize
+Dump instruction size and location in the assembly code.
-@item -mauto-pic
-@opindex mauto-pic
-Generate code that is self-relocatable. This implies @option{-mconstant-gp}.
-This is useful when compiling firmware code.
+@item -mpadstruct
+@opindex mpadstruct
+This option is deprecated. It pads structures to multiple of 4 bytes,
+which is incompatible with the SH ABI@.
-@item -minline-divide-min-latency
-@opindex minline-divide-min-latency
-Generate code for inline divides using the minimum latency algorithm.
+@item -mspace
+@opindex mspace
+Optimize for space instead of speed. Implied by @option{-Os}.
-@item -minline-divide-max-throughput
-@opindex minline-divide-max-throughput
-Generate code for inline divides using the maximum throughput algorithm.
+@item -mprefergot
+@opindex mprefergot
+When generating position-independent code, emit function calls using
+the Global Offset Table instead of the Procedure Linkage Table.
-@item -mno-dwarf2-asm
-@itemx -mdwarf2-asm
-@opindex mno-dwarf2-asm
-@opindex mdwarf2-asm
-Don't (or do) generate assembler code for the DWARF2 line number debugging
-info. This may be useful when not using the GNU assembler.
+@item -musermode
+@opindex musermode
+Don't generate privileged mode only code; implies -mno-inline-ic_invalidate
+if the inlined code would not work in user mode.
+This is the default when the target is @code{sh-*-linux*}.
+
+@item -multcost=@var{number}
+@opindex multcost=@var{number}
+Set the cost to assume for a multiply insn.
+
+@item -mdiv=@var{strategy}
+@opindex mdiv=@var{strategy}
+Set the division strategy to use for SHmedia code. @var{strategy} must be
+one of: call, call2, fp, inv, inv:minlat, inv20u, inv20l, inv:call,
+inv:call2, inv:fp .
+"fp" performs the operation in floating point. This has a very high latency,
+but needs only a few instructions, so it might be a good choice if
+your code has enough easily exploitable ILP to allow the compiler to
+schedule the floating point instructions together with other instructions.
+Division by zero causes a floating point exception.
+"inv" uses integer operations to calculate the inverse of the divisor,
+and then multiplies the dividend with the inverse. This strategy allows
+cse and hoisting of the inverse calculation. Division by zero calculates
+an unspecified result, but does not trap.
+"inv:minlat" is a variant of "inv" where if no cse / hoisting opportunities
+have been found, or if the entire operation has been hoisted to the same
+place, the last stages of the inverse calculation are intertwined with the
+final multiply to reduce the overall latency, at the expense of using a few
+more instructions, and thus offering fewer scheduling opportunities with
+other code.
+"call" calls a library function that usually implements the inv:minlat
+strategy.
+This gives high code density for m5-*media-nofpu compilations.
+"call2" uses a different entry point of the same library function, where it
+assumes that a pointer to a lookup table has already been set up, which
+exposes the pointer load to cse / code hoisting optimizations.
+"inv:call", "inv:call2" and "inv:fp" all use the "inv" algorithm for initial
+code generation, but if the code stays unoptimized, revert to the "call",
+"call2", or "fp" strategies, respectively. Note that the
+potentially-trapping side effect of division by zero is carried by a
+separate instruction, so it is possible that all the integer instructions
+are hoisted out, but the marker for the side effect stays where it is.
+A recombination to fp operations or a call is not possible in that case.
+"inv20u" and "inv20l" are variants of the "inv:minlat" strategy. In the case
+that the inverse calculation was nor separated from the multiply, they speed
+up division where the dividend fits into 20 bits (plus sign where applicable),
+by inserting a test to skip a number of operations in this case; this test
+slows down the case of larger dividends. inv20u assumes the case of a such
+a small dividend to be unlikely, and inv20l assumes it to be likely.
+
+@item -mdivsi3_libfunc=@var{name}
+@opindex mdivsi3_libfunc=@var{name}
+Set the name of the library function used for 32 bit signed division to
+@var{name}. This only affect the name used in the call and inv:call
+division strategies, and the compiler will still expect the same
+sets of input/output/clobbered registers as if this option was not present.
@item -mfixed-range=@var{register-range}
@opindex mfixed-range
useful when compiling kernel code. A register range is specified as
two registers separated by a dash. Multiple register ranges can be
specified separated by a comma.
+
+@item -madjust-unroll
+@opindex madjust-unroll
+Throttle unrolling to avoid thrashing target registers.
+This option only has an effect if the gcc code base supports the
+TARGET_ADJUST_UNROLL_MAX target hook.
+
+@item -mindexed-addressing
+@opindex mindexed-addressing
+Enable the use of the indexed addressing mode for SHmedia32/SHcompact.
+This is only safe if the hardware and/or OS implement 32 bit wrap-around
+semantics for the indexed addressing mode. The architecture allows the
+implementation of processors with 64 bit MMU, which the OS could use to
+get 32 bit addressing, but since no current hardware implementation supports
+this or any other way to make the indexed addressing mode safe to use in
+the 32 bit ABI, the default is -mno-indexed-addressing.
+
+@item -mgettrcost=@var{number}
+@opindex mgettrcost=@var{number}
+Set the cost assumed for the gettr instruction to @var{number}.
+The default is 2 if @option{-mpt-fixed} is in effect, 100 otherwise.
+
+@item -mpt-fixed
+@opindex mpt-fixed
+Assume pt* instructions won't trap. This will generally generate better
+scheduled code, but is unsafe on current hardware. The current architecture
+definition says that ptabs and ptrel trap when the target anded with 3 is 3.
+This has the unintentional effect of making it unsafe to schedule ptabs /
+ptrel before a branch, or hoist it out of a loop. For example,
+__do_global_ctors, a part of libgcc that runs constructors at program
+startup, calls functions in a list which is delimited by @minus{}1. With the
+-mpt-fixed option, the ptabs will be done before testing against @minus{}1.
+That means that all the constructors will be run a bit quicker, but when
+the loop comes to the end of the list, the program crashes because ptabs
+loads @minus{}1 into a target register. Since this option is unsafe for any
+hardware implementing the current architecture specification, the default
+is -mno-pt-fixed. Unless the user specifies a specific cost with
+@option{-mgettrcost}, -mno-pt-fixed also implies @option{-mgettrcost=100};
+this deters register allocation using target registers for storing
+ordinary integers.
+
+@item -minvalid-symbols
+@opindex minvalid-symbols
+Assume symbols might be invalid. Ordinary function symbols generated by
+the compiler will always be valid to load with movi/shori/ptabs or
+movi/shori/ptrel, but with assembler and/or linker tricks it is possible
+to generate symbols that will cause ptabs / ptrel to trap.
+This option is only meaningful when @option{-mno-pt-fixed} is in effect.
+It will then prevent cross-basic-block cse, hoisting and most scheduling
+of symbol loads. The default is @option{-mno-invalid-symbols}.
@end table
-@node D30V Options
-@subsection D30V Options
-@cindex D30V Options
+@node SPARC Options
+@subsection SPARC Options
+@cindex SPARC options
-These @samp{-m} options are defined for D30V implementations:
+These @samp{-m} options are supported on the SPARC:
@table @gcctabopt
-@item -mextmem
-@opindex mextmem
-Link the @samp{.text}, @samp{.data}, @samp{.bss}, @samp{.strings},
-@samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections into external
-memory, which starts at location @code{0x80000000}.
-
-@item -mextmemory
-@opindex mextmemory
-Same as the @option{-mextmem} switch.
-
-@item -monchip
-@opindex monchip
-Link the @samp{.text} section into onchip text memory, which starts at
-location @code{0x0}. Also link @samp{.data}, @samp{.bss},
-@samp{.strings}, @samp{.rodata}, @samp{.rodata1}, @samp{.data1} sections
-into onchip data memory, which starts at location @code{0x20000000}.
-
-@item -mno-asm-optimize
-@itemx -masm-optimize
-@opindex mno-asm-optimize
-@opindex masm-optimize
-Disable (enable) passing @option{-O} to the assembler when optimizing.
-The assembler uses the @option{-O} option to automatically parallelize
-adjacent short instructions where possible.
-
-@item -mbranch-cost=@var{n}
-@opindex mbranch-cost
-Increase the internal costs of branches to @var{n}. Higher costs means
-that the compiler will issue more instructions to avoid doing a branch.
-The default is 2.
+@item -mno-app-regs
+@itemx -mapp-regs
+@opindex mno-app-regs
+@opindex mapp-regs
+Specify @option{-mapp-regs} to generate output using the global registers
+2 through 4, which the SPARC SVR4 ABI reserves for applications. This
+is the default.
-@item -mcond-exec=@var{n}
-@opindex mcond-exec
-Specify the maximum number of conditionally executed instructions that
-replace a branch. The default is 4.
+To be fully SVR4 ABI compliant at the cost of some performance loss,
+specify @option{-mno-app-regs}. You should compile libraries and system
+software with this option.
+
+@item -mfpu
+@itemx -mhard-float
+@opindex mfpu
+@opindex mhard-float
+Generate output containing floating point instructions. This is the
+default.
+
+@item -mno-fpu
+@itemx -msoft-float
+@opindex mno-fpu
+@opindex msoft-float
+Generate output containing library calls for floating point.
+@strong{Warning:} the requisite libraries are not available for all SPARC
+targets. Normally the facilities of the machine's usual C compiler are
+used, but this cannot be done directly in cross-compilation. You must make
+your own arrangements to provide suitable library functions for
+cross-compilation. The embedded targets @samp{sparc-*-aout} and
+@samp{sparclite-*-*} do provide software floating point support.
+
+@option{-msoft-float} changes the calling convention in the output file;
+therefore, it is only useful if you compile @emph{all} of a program with
+this option. In particular, you need to compile @file{libgcc.a}, the
+library that comes with GCC, with @option{-msoft-float} in order for
+this to work.
+
+@item -mhard-quad-float
+@opindex mhard-quad-float
+Generate output containing quad-word (long double) floating point
+instructions.
+
+@item -msoft-quad-float
+@opindex msoft-quad-float
+Generate output containing library calls for quad-word (long double)
+floating point instructions. The functions called are those specified
+in the SPARC ABI@. This is the default.
+
+As of this writing, there are no SPARC implementations that have hardware
+support for the quad-word floating point instructions. They all invoke
+a trap handler for one of these instructions, and then the trap handler
+emulates the effect of the instruction. Because of the trap handler overhead,
+this is much slower than calling the ABI library routines. Thus the
+@option{-msoft-quad-float} option is the default.
+
+@item -mno-unaligned-doubles
+@itemx -munaligned-doubles
+@opindex mno-unaligned-doubles
+@opindex munaligned-doubles
+Assume that doubles have 8 byte alignment. This is the default.
+
+With @option{-munaligned-doubles}, GCC assumes that doubles have 8 byte
+alignment only if they are contained in another type, or if they have an
+absolute address. Otherwise, it assumes they have 4 byte alignment.
+Specifying this option avoids some rare compatibility problems with code
+generated by other compilers. It is not the default because it results
+in a performance loss, especially for floating point code.
+
+@item -mno-faster-structs
+@itemx -mfaster-structs
+@opindex mno-faster-structs
+@opindex mfaster-structs
+With @option{-mfaster-structs}, the compiler assumes that structures
+should have 8 byte alignment. This enables the use of pairs of
+@code{ldd} and @code{std} instructions for copies in structure
+assignment, in place of twice as many @code{ld} and @code{st} pairs.
+However, the use of this changed alignment directly violates the SPARC
+ABI@. Thus, it's intended only for use on targets where the developer
+acknowledges that their resulting code will not be directly in line with
+the rules of the ABI@.
+
+@item -mimpure-text
+@opindex mimpure-text
+@option{-mimpure-text}, used in addition to @option{-shared}, tells
+the compiler to not pass @option{-z text} to the linker when linking a
+shared object. Using this option, you can link position-dependent
+code into a shared object.
+
+@option{-mimpure-text} suppresses the ``relocations remain against
+allocatable but non-writable sections'' linker error message.
+However, the necessary relocations will trigger copy-on-write, and the
+shared object is not actually shared across processes. Instead of
+using @option{-mimpure-text}, you should compile all source code with
+@option{-fpic} or @option{-fPIC}.
+
+This option is only available on SunOS and Solaris.
+
+@item -mcpu=@var{cpu_type}
+@opindex mcpu
+Set the instruction set, register set, and instruction scheduling parameters
+for machine type @var{cpu_type}. Supported values for @var{cpu_type} are
+@samp{v7}, @samp{cypress}, @samp{v8}, @samp{supersparc}, @samp{sparclite},
+@samp{f930}, @samp{f934}, @samp{hypersparc}, @samp{sparclite86x},
+@samp{sparclet}, @samp{tsc701}, @samp{v9}, @samp{ultrasparc},
+@samp{ultrasparc3}, @samp{niagara} and @samp{niagara2}.
+
+Default instruction scheduling parameters are used for values that select
+an architecture and not an implementation. These are @samp{v7}, @samp{v8},
+@samp{sparclite}, @samp{sparclet}, @samp{v9}.
+
+Here is a list of each supported architecture and their supported
+implementations.
+
+@smallexample
+ v7: cypress
+ v8: supersparc, hypersparc
+ sparclite: f930, f934, sparclite86x
+ sparclet: tsc701
+ v9: ultrasparc, ultrasparc3, niagara, niagara2
+@end smallexample
+
+By default (unless configured otherwise), GCC generates code for the V7
+variant of the SPARC architecture. With @option{-mcpu=cypress}, the compiler
+additionally optimizes it for the Cypress CY7C602 chip, as used in the
+SPARCStation/SPARCServer 3xx series. This is also appropriate for the older
+SPARCStation 1, 2, IPX etc.
+
+With @option{-mcpu=v8}, GCC generates code for the V8 variant of the SPARC
+architecture. The only difference from V7 code is that the compiler emits
+the integer multiply and integer divide instructions which exist in SPARC-V8
+but not in SPARC-V7. With @option{-mcpu=supersparc}, the compiler additionally
+optimizes it for the SuperSPARC chip, as used in the SPARCStation 10, 1000 and
+2000 series.
+
+With @option{-mcpu=sparclite}, GCC generates code for the SPARClite variant of
+the SPARC architecture. This adds the integer multiply, integer divide step
+and scan (@code{ffs}) instructions which exist in SPARClite but not in SPARC-V7.
+With @option{-mcpu=f930}, the compiler additionally optimizes it for the
+Fujitsu MB86930 chip, which is the original SPARClite, with no FPU@. With
+@option{-mcpu=f934}, the compiler additionally optimizes it for the Fujitsu
+MB86934 chip, which is the more recent SPARClite with FPU@.
+
+With @option{-mcpu=sparclet}, GCC generates code for the SPARClet variant of
+the SPARC architecture. This adds the integer multiply, multiply/accumulate,
+integer divide step and scan (@code{ffs}) instructions which exist in SPARClet
+but not in SPARC-V7. With @option{-mcpu=tsc701}, the compiler additionally
+optimizes it for the TEMIC SPARClet chip.
+
+With @option{-mcpu=v9}, GCC generates code for the V9 variant of the SPARC
+architecture. This adds 64-bit integer and floating-point move instructions,
+3 additional floating-point condition code registers and conditional move
+instructions. With @option{-mcpu=ultrasparc}, the compiler additionally
+optimizes it for the Sun UltraSPARC I/II/IIi chips. With
+@option{-mcpu=ultrasparc3}, the compiler additionally optimizes it for the
+Sun UltraSPARC III/III+/IIIi/IIIi+/IV/IV+ chips. With
+@option{-mcpu=niagara}, the compiler additionally optimizes it for
+Sun UltraSPARC T1 chips. With @option{-mcpu=niagara2}, the compiler
+additionally optimizes it for Sun UltraSPARC T2 chips.
+
+@item -mtune=@var{cpu_type}
+@opindex mtune
+Set the instruction scheduling parameters for machine type
+@var{cpu_type}, but do not set the instruction set or register set that the
+option @option{-mcpu=@var{cpu_type}} would.
+
+The same values for @option{-mcpu=@var{cpu_type}} can be used for
+@option{-mtune=@var{cpu_type}}, but the only useful values are those
+that select a particular cpu implementation. Those are @samp{cypress},
+@samp{supersparc}, @samp{hypersparc}, @samp{f930}, @samp{f934},
+@samp{sparclite86x}, @samp{tsc701}, @samp{ultrasparc},
+@samp{ultrasparc3}, @samp{niagara}, and @samp{niagara2}.
+
+@item -mv8plus
+@itemx -mno-v8plus
+@opindex mv8plus
+@opindex mno-v8plus
+With @option{-mv8plus}, GCC generates code for the SPARC-V8+ ABI@. The
+difference from the V8 ABI is that the global and out registers are
+considered 64-bit wide. This is enabled by default on Solaris in 32-bit
+mode for all SPARC-V9 processors.
+
+@item -mvis
+@itemx -mno-vis
+@opindex mvis
+@opindex mno-vis
+With @option{-mvis}, GCC generates code that takes advantage of the UltraSPARC
+Visual Instruction Set extensions. The default is @option{-mno-vis}.
@end table
-@node S/390 and zSeries Options
-@subsection S/390 and zSeries Options
-@cindex S/390 and zSeries Options
-
-These are the @samp{-m} options defined for the S/390 and zSeries architecture.
+These @samp{-m} options are supported in addition to the above
+on SPARC-V9 processors in 64-bit environments:
@table @gcctabopt
-@item -mhard-float
-@itemx -msoft-float
-@opindex mhard-float
-@opindex msoft-float
-Use (do not use) the hardware floating-point instructions and registers
-for floating-point operations. When @option{-msoft-float} is specified,
-functions in @file{libgcc.a} will be used to perform floating-point
-operations. When @option{-mhard-float} is specified, the compiler
-generates IEEE floating-point instructions. This is the default.
+@item -mlittle-endian
+@opindex mlittle-endian
+Generate code for a processor running in little-endian mode. It is only
+available for a few configurations and most notably not on Solaris and Linux.
-@item -mbackchain
-@itemx -mno-backchain
-@opindex mbackchain
-@opindex mno-backchain
-Generate (or do not generate) code which maintains an explicit
-backchain within the stack frame that points to the caller's frame.
-This is currently needed to allow debugging. The default is to
-generate the backchain.
+@item -m32
+@itemx -m64
+@opindex m32
+@opindex m64
+Generate code for a 32-bit or 64-bit environment.
+The 32-bit environment sets int, long and pointer to 32 bits.
+The 64-bit environment sets int to 32 bits and long and pointer
+to 64 bits.
-@item -msmall-exec
-@itemx -mno-small-exec
-@opindex msmall-exec
-@opindex mno-small-exec
-Generate (or do not generate) code using the @code{bras} instruction
-to do subroutine calls.
-This only works reliably if the total executable size does not
-exceed 64k. The default is to use the @code{basr} instruction instead,
-which does not have this limitation.
+@item -mcmodel=medlow
+@opindex mcmodel=medlow
+Generate code for the Medium/Low code model: 64-bit addresses, programs
+must be linked in the low 32 bits of memory. Programs can be statically
+or dynamically linked.
-@item -m64
-@itemx -m31
-@opindex m64
-@opindex m31
-When @option{-m31} is specified, generate code compliant to the
-Linux for S/390 ABI@. When @option{-m64} is specified, generate
-code compliant to the Linux for zSeries ABI@. This allows GCC in
-particular to generate 64-bit instructions. For the @samp{s390}
-targets, the default is @option{-m31}, while the @samp{s390x}
-targets default to @option{-m64}.
+@item -mcmodel=medmid
+@opindex mcmodel=medmid
+Generate code for the Medium/Middle code model: 64-bit addresses, programs
+must be linked in the low 44 bits of memory, the text and data segments must
+be less than 2GB in size and the data segment must be located within 2GB of
+the text segment.
-@item -mmvcle
-@itemx -mno-mvcle
-@opindex mmvcle
-@opindex mno-mvcle
-Generate (or do not generate) code using the @code{mvcle} instruction
-to perform block moves. When @option{-mno-mvcle} is specifed,
-use a @code{mvc} loop instead. This is the default.
+@item -mcmodel=medany
+@opindex mcmodel=medany
+Generate code for the Medium/Anywhere code model: 64-bit addresses, programs
+may be linked anywhere in memory, the text and data segments must be less
+than 2GB in size and the data segment must be located within 2GB of the
+text segment.
-@item -mdebug
-@itemx -mno-debug
-@opindex mdebug
-@opindex mno-debug
-Print (or do not print) additional debug information when compiling.
-The default is to not print debug information.
+@item -mcmodel=embmedany
+@opindex mcmodel=embmedany
+Generate code for the Medium/Anywhere code model for embedded systems:
+64-bit addresses, the text and data segments must be less than 2GB in
+size, both starting anywhere in memory (determined at link time). The
+global register %g4 points to the base of the data segment. Programs
+are statically linked and PIC is not supported.
+@item -mstack-bias
+@itemx -mno-stack-bias
+@opindex mstack-bias
+@opindex mno-stack-bias
+With @option{-mstack-bias}, GCC assumes that the stack pointer, and
+frame pointer if present, are offset by @minus{}2047 which must be added back
+when making stack frame references. This is the default in 64-bit mode.
+Otherwise, assume no such offset is present.
@end table
-@node CRIS Options
-@subsection CRIS Options
-@cindex CRIS Options
-
-These options are defined specifically for the CRIS ports.
+These switches are supported in addition to the above on Solaris:
@table @gcctabopt
-@item -march=@var{architecture-type}
-@itemx -mcpu=@var{architecture-type}
-@opindex march
-@opindex mcpu
-Generate code for the specified architecture. The choices for
-@var{architecture-type} are @samp{v3}, @samp{v8} and @samp{v10} for
-respectively ETRAX@w{ }4, ETRAX@w{ }100, and ETRAX@w{ }100@w{ }LX.
-Default is @samp{v0} except for cris-axis-linux-gnu, where the default is
-@samp{v10}.
-
-@item -mtune=@var{architecture-type}
-@opindex mtune
-Tune to @var{architecture-type} everything applicable about the generated
-code, except for the ABI and the set of available instructions. The
-choices for @var{architecture-type} are the same as for
-@option{-march=@var{architecture-type}}.
-
-@item -mmax-stack-frame=@var{n}
-@opindex mmax-stack-frame
-Warn when the stack frame of a function exceeds @var{n} bytes.
+@item -threads
+@opindex threads
+Add support for multithreading using the Solaris threads library. This
+option sets flags for both the preprocessor and linker. This option does
+not affect the thread safety of object code produced by the compiler or
+that of libraries supplied with it.
+
+@item -pthreads
+@opindex pthreads
+Add support for multithreading using the POSIX threads library. This
+option sets flags for both the preprocessor and linker. This option does
+not affect the thread safety of object code produced by the compiler or
+that of libraries supplied with it.
-@item -melinux-stacksize=@var{n}
-@opindex melinux-stacksize
-Only available with the @samp{cris-axis-aout} target. Arranges for
-indications in the program to the kernel loader that the stack of the
-program should be set to @var{n} bytes.
-
-@item -metrax4
-@itemx -metrax100
-@opindex metrax4
-@opindex metrax100
-The options @option{-metrax4} and @option{-metrax100} are synonyms for
-@option{-march=v3} and @option{-march=v8} respectively.
+@item -pthread
+@opindex pthread
+This is a synonym for @option{-pthreads}.
+@end table
-@item -mpdebug
-@opindex mpdebug
-Enable CRIS-specific verbose debug-related information in the assembly
-code. This option also has the effect to turn off the @samp{#NO_APP}
-formatted-code indicator to the assembler at the beginning of the
-assembly file.
+@node SPU Options
+@subsection SPU Options
+@cindex SPU options
-@item -mcc-init
-@opindex mcc-init
-Do not use condition-code results from previous instruction; always emit
-compare and test instructions before use of condition codes.
+These @samp{-m} options are supported on the SPU:
-@item -mno-side-effects
-@opindex mno-side-effects
-Do not emit instructions with side-effects in addressing modes other than
-post-increment.
+@table @gcctabopt
+@item -mwarn-reloc
+@itemx -merror-reloc
+@opindex mwarn-reloc
+@opindex merror-reloc
+
+The loader for SPU does not handle dynamic relocations. By default, GCC
+will give an error when it generates code that requires a dynamic
+relocation. @option{-mno-error-reloc} disables the error,
+@option{-mwarn-reloc} will generate a warning instead.
+
+@item -msafe-dma
+@itemx -munsafe-dma
+@opindex msafe-dma
+@opindex munsafe-dma
+
+Instructions which initiate or test completion of DMA must not be
+reordered with respect to loads and stores of the memory which is being
+accessed. Users typically address this problem using the volatile
+keyword, but that can lead to inefficient code in places where the
+memory is known to not change. Rather than mark the memory as volatile
+we treat the DMA instructions as potentially effecting all memory. With
+@option{-munsafe-dma} users must use the volatile keyword to protect
+memory accesses.
+
+@item -mbranch-hints
+@opindex mbranch-hints
+
+By default, GCC will generate a branch hint instruction to avoid
+pipeline stalls for always taken or probably taken branches. A hint
+will not be generated closer than 8 instructions away from its branch.
+There is little reason to disable them, except for debugging purposes,
+or to make an object a little bit smaller.
+
+@item -msmall-mem
+@itemx -mlarge-mem
+@opindex msmall-mem
+@opindex mlarge-mem
+
+By default, GCC generates code assuming that addresses are never larger
+than 18 bits. With @option{-mlarge-mem} code is generated that assumes
+a full 32 bit address.
+
+@item -mstdmain
+@opindex mstdmain
+
+By default, GCC links against startup code that assumes the SPU-style
+main function interface (which has an unconventional parameter list).
+With @option{-mstdmain}, GCC will link your program against startup
+code that assumes a C99-style interface to @code{main}, including a
+local copy of @code{argv} strings.
-@item -mstack-align
-@itemx -mno-stack-align
-@itemx -mdata-align
-@itemx -mno-data-align
-@itemx -mconst-align
-@itemx -mno-const-align
-@opindex mstack-align
-@opindex mno-stack-align
-@opindex mdata-align
-@opindex mno-data-align
-@opindex mconst-align
-@opindex mno-const-align
-These options (no-options) arranges (eliminate arrangements) for the
-stack-frame, individual data and constants to be aligned for the maximum
-single data access size for the chosen CPU model. The default is to
-arrange for 32-bit alignment. ABI details such as structure layout are
-not affected by these options.
+@item -mfixed-range=@var{register-range}
+@opindex mfixed-range
+Generate code treating the given register range as fixed registers.
+A fixed register is one that the register allocator can not use. This is
+useful when compiling kernel code. A register range is specified as
+two registers separated by a dash. Multiple register ranges can be
+specified separated by a comma.
-@item -m32-bit
-@itemx -m16-bit
-@itemx -m8-bit
-@opindex m32-bit
-@opindex m16-bit
-@opindex m8-bit
-Similar to the stack- data- and const-align options above, these options
-arrange for stack-frame, writable data and constants to all be 32-bit,
-16-bit or 8-bit aligned. The default is 32-bit alignment.
+@item -mdual-nops
+@itemx -mdual-nops=@var{n}
+@opindex mdual-nops
+By default, GCC will insert nops to increase dual issue when it expects
+it to increase performance. @var{n} can be a value from 0 to 10. A
+smaller @var{n} will insert fewer nops. 10 is the default, 0 is the
+same as @option{-mno-dual-nops}. Disabled with @option{-Os}.
+
+@item -mhint-max-nops=@var{n}
+@opindex mhint-max-nops
+Maximum number of nops to insert for a branch hint. A branch hint must
+be at least 8 instructions away from the branch it is effecting. GCC
+will insert up to @var{n} nops to enforce this, otherwise it will not
+generate the branch hint.
+
+@item -mhint-max-distance=@var{n}
+@opindex mhint-max-distance
+The encoding of the branch hint instruction limits the hint to be within
+256 instructions of the branch it is effecting. By default, GCC makes
+sure it is within 125.
+
+@item -msafe-hints
+@opindex msafe-hints
+Work around a hardware bug which causes the SPU to stall indefinitely.
+By default, GCC will insert the @code{hbrp} instruction to make sure
+this stall won't happen.
-@item -mno-prologue-epilogue
-@itemx -mprologue-epilogue
-@opindex mno-prologue-epilogue
-@opindex mprologue-epilogue
-With @option{-mno-prologue-epilogue}, the normal function prologue and
-epilogue that sets up the stack-frame are omitted and no return
-instructions or return sequences are generated in the code. Use this
-option only together with visual inspection of the compiled code: no
-warnings or errors are generated when call-saved registers must be saved,
-or storage for local variable needs to be allocated.
+@end table
-@item -mno-gotplt
-@itemx -mgotplt
-@opindex mno-gotplt
-@opindex mgotplt
-With @option{-fpic} and @option{-fPIC}, don't generate (do generate)
-instruction sequences that load addresses for functions from the PLT part
-of the GOT rather than (traditional on other architectures) calls to the
-PLT. The default is @option{-mgotplt}.
+@node System V Options
+@subsection Options for System V
-@item -maout
-@opindex maout
-Legacy no-op option only recognized with the cris-axis-aout target.
+These additional options are available on System V Release 4 for
+compatibility with other compilers on those systems:
-@item -melf
-@opindex melf
-Legacy no-op option only recognized with the cris-axis-elf and
-cris-axis-linux-gnu targets.
+@table @gcctabopt
+@item -G
+@opindex G
+Create a shared object.
+It is recommended that @option{-symbolic} or @option{-shared} be used instead.
-@item -melinux
-@opindex melinux
-Only recognized with the cris-axis-aout target, where it selects a
-GNU/linux-like multilib, include files and instruction set for
-@option{-march=v8}.
+@item -Qy
+@opindex Qy
+Identify the versions of each tool used by the compiler, in a
+@code{.ident} assembler directive in the output.
-@item -mlinux
-@opindex mlinux
-Legacy no-op option only recognized with the cris-axis-linux-gnu target.
+@item -Qn
+@opindex Qn
+Refrain from adding @code{.ident} directives to the output file (this is
+the default).
-@item -sim
-@opindex sim
-This option, recognized for the cris-axis-aout and cris-axis-elf arranges
-to link with input-output functions from a simulator library. Code,
-initialized data and zero-initialized data are allocated consecutively.
+@item -YP,@var{dirs}
+@opindex YP
+Search the directories @var{dirs}, and no others, for libraries
+specified with @option{-l}.
-@item -sim2
-@opindex sim2
-Like @option{-sim}, but pass linker options to locate initialized data at
-0x40000000 and zero-initialized data at 0x80000000.
+@item -Ym,@var{dir}
+@opindex Ym
+Look in the directory @var{dir} to find the M4 preprocessor.
+The assembler uses this option.
+@c This is supposed to go with a -Yd for predefined M4 macro files, but
+@c the generic assembler that comes with Solaris takes just -Ym.
@end table
-@node MMIX Options
-@subsection MMIX Options
-@cindex MMIX Options
+@node V850 Options
+@subsection V850 Options
+@cindex V850 Options
-These options are defined for the MMIX:
+These @samp{-m} options are defined for V850 implementations:
@table @gcctabopt
-@item -mlibfuncs
-@itemx -mno-libfuncs
-@opindex mlibfuncs
-@opindex mno-libfuncs
-Specify that intrinsic library functions are being compiled, passing all
-values in registers, no matter the size.
-
-@item -mepsilon
-@itemx -mno-epsilon
-@opindex mepsilon
-@opindex mno-epsilon
-Generate floating-point comparison instructions that compare with respect
-to the @code{rE} epsilon register.
+@item -mlong-calls
+@itemx -mno-long-calls
+@opindex mlong-calls
+@opindex mno-long-calls
+Treat all calls as being far away (near). If calls are assumed to be
+far away, the compiler will always load the functions address up into a
+register, and call indirect through the pointer.
-@item -mabi=mmixware
-@itemx -mabi=gnu
-@opindex mabi-mmixware
-@opindex mabi=gnu
-Generate code that passes function parameters and return values that (in
-the called function) are seen as registers @code{$0} and up, as opposed to
-the GNU ABI which uses global registers @code{$231} and up.
+@item -mno-ep
+@itemx -mep
+@opindex mno-ep
+@opindex mep
+Do not optimize (do optimize) basic blocks that use the same index
+pointer 4 or more times to copy pointer into the @code{ep} register, and
+use the shorter @code{sld} and @code{sst} instructions. The @option{-mep}
+option is on by default if you optimize.
-@item -mzero-extend
-@itemx -mno-zero-extend
-@opindex mzero-extend
-@opindex mno-zero-extend
-When reading data from memory in sizes shorter than 64 bits, use (do not
-use) zero-extending load instructions by default, rather than
-sign-extending ones.
+@item -mno-prolog-function
+@itemx -mprolog-function
+@opindex mno-prolog-function
+@opindex mprolog-function
+Do not use (do use) external functions to save and restore registers
+at the prologue and epilogue of a function. The external functions
+are slower, but use less code space if more than one function saves
+the same number of registers. The @option{-mprolog-function} option
+is on by default if you optimize.
-@item -mknuthdiv
-@itemx -mno-knuthdiv
-@opindex mknuthdiv
-@opindex mno-knuthdiv
-Make the result of a division yielding a remainder have the same sign as
-the divisor. With the default, @option{-mno-knuthdiv}, the sign of the
-remainder follows the sign of the dividend. Both methods are
-arithmetically valid, the latter being almost exclusively used.
+@item -mspace
+@opindex mspace
+Try to make the code as small as possible. At present, this just turns
+on the @option{-mep} and @option{-mprolog-function} options.
-@item -mtoplevel-symbols
-@itemx -mno-toplevel-symbols
-@opindex mtoplevel-symbols
-@opindex mno-toplevel-symbols
-Prepend (do not prepend) a @samp{:} to all global symbols, so the assembly
-code can be used with the @code{PREFIX} assembly directive.
+@item -mtda=@var{n}
+@opindex mtda
+Put static or global variables whose size is @var{n} bytes or less into
+the tiny data area that register @code{ep} points to. The tiny data
+area can hold up to 256 bytes in total (128 bytes for byte references).
-@item -melf
-@opindex melf
-Generate an executable in the ELF format, rather than the default
-@samp{mmo} format used by the @command{mmix} simulator.
+@item -msda=@var{n}
+@opindex msda
+Put static or global variables whose size is @var{n} bytes or less into
+the small data area that register @code{gp} points to. The small data
+area can hold up to 64 kilobytes.
-@item -mbranch-predict
-@itemx -mno-branch-predict
-@opindex mbranch-predict
-@opindex mno-branch-predict
-Use (do not use) the probable-branch instructions, when static branch
-prediction indicates a probable branch.
+@item -mzda=@var{n}
+@opindex mzda
+Put static or global variables whose size is @var{n} bytes or less into
+the first 32 kilobytes of memory.
-@item -mbase-addresses
-@itemx -mno-base-addresses
-@opindex mbase-addresses
-@opindex mno-base-addresses
-Generate (do not generate) code that uses @emph{base addresses}. Using a
-base address automatically generates a request (handled by the assembler
-and the linker) for a constant to be set up in a global register. The
-register is used for one or more base address requests within the range 0
-to 255 from the value held in the register. The generally leads to short
-and fast code, but the number of different data items that can be
-addressed is limited. This means that a program that uses lots of static
-data may require @option{-mno-base-addresses}.
-@end table
+@item -mv850
+@opindex mv850
+Specify that the target processor is the V850.
-@node PDP-11 Options
-@subsection PDP-11 Options
-@cindex PDP-11 Options
+@item -mbig-switch
+@opindex mbig-switch
+Generate code suitable for big switch tables. Use this option only if
+the assembler/linker complain about out of range branches within a switch
+table.
-These options are defined for the PDP-11:
+@item -mapp-regs
+@opindex mapp-regs
+This option will cause r2 and r5 to be used in the code generated by
+the compiler. This setting is the default.
-@table @gcctabopt
-@item -mfpu
-@opindex mfpu
-Use hardware FPP floating point. This is the default. (FIS floating
-point on the PDP-11/40 is not supported.)
+@item -mno-app-regs
+@opindex mno-app-regs
+This option will cause r2 and r5 to be treated as fixed registers.
-@item -msoft-float
-@opindex msoft-float
-Do not use hardware floating point.
+@item -mv850e1
+@opindex mv850e1
+Specify that the target processor is the V850E1. The preprocessor
+constants @samp{__v850e1__} and @samp{__v850e__} will be defined if
+this option is used.
-@item -mac0
-@opindex mac0
-Return floating-point results in ac0 (fr0 in Unix assembler syntax).
+@item -mv850e
+@opindex mv850e
+Specify that the target processor is the V850E@. The preprocessor
+constant @samp{__v850e__} will be defined if this option is used.
-@item -mno-ac0
-@opindex mno-ac0
-Return floating-point results in memory. This is the default.
+If neither @option{-mv850} nor @option{-mv850e} nor @option{-mv850e1}
+are defined then a default target processor will be chosen and the
+relevant @samp{__v850*__} preprocessor constant will be defined.
-@item -m40
-@opindex m40
-Generate code for a PDP-11/40.
+The preprocessor constants @samp{__v850} and @samp{__v851__} are always
+defined, regardless of which processor variant is the target.
-@item -m45
-@opindex m45
-Generate code for a PDP-11/45. This is the default.
+@item -mdisable-callt
+@opindex mdisable-callt
+This option will suppress generation of the CALLT instruction for the
+v850e and v850e1 flavors of the v850 architecture. The default is
+@option{-mno-disable-callt} which allows the CALLT instruction to be used.
-@item -m10
-@opindex m10
-Generate code for a PDP-11/10.
+@end table
-@item -mbcopy-builtin
-@opindex bcopy-builtin
-Use inline @code{movstrhi} patterns for copying memory. This is the
-default.
+@node VAX Options
+@subsection VAX Options
+@cindex VAX options
-@item -mbcopy
-@opindex mbcopy
-Do not use inline @code{movstrhi} patterns for copying memory.
+These @samp{-m} options are defined for the VAX:
-@item -mint16
-@itemx -mno-int32
-@opindex mint16
-@opindex mno-int32
-Use 16-bit @code{int}. This is the default.
+@table @gcctabopt
+@item -munix
+@opindex munix
+Do not output certain jump instructions (@code{aobleq} and so on)
+that the Unix assembler for the VAX cannot handle across long
+ranges.
-@item -mint32
-@itemx -mno-int16
-@opindex mint32
-@opindex mno-int16
-Use 32-bit @code{int}.
+@item -mgnu
+@opindex mgnu
+Do output those jump instructions, on the assumption that you
+will assemble with the GNU assembler.
-@item -mfloat64
-@itemx -mno-float32
-@opindex mfloat64
-@opindex mno-float32
-Use 64-bit @code{float}. This is the default.
+@item -mg
+@opindex mg
+Output code for g-format floating point numbers instead of d-format.
+@end table
-@item -mfloat32
-@item -mno-float64
-@opindex mfloat32
-@opindex mno-float64
-Use 32-bit @code{float}.
+@node VxWorks Options
+@subsection VxWorks Options
+@cindex VxWorks Options
-@item -mabshi
-@opindex mabshi
-Use @code{abshi2} pattern. This is the default.
+The options in this section are defined for all VxWorks targets.
+Options specific to the target hardware are listed with the other
+options for that target.
-@item -mno-abshi
-@opindex mno-abshi
-Do not use @code{abshi2} pattern.
+@table @gcctabopt
+@item -mrtp
+@opindex mrtp
+GCC can generate code for both VxWorks kernels and real time processes
+(RTPs). This option switches from the former to the latter. It also
+defines the preprocessor macro @code{__RTP__}.
+
+@item -non-static
+@opindex non-static
+Link an RTP executable against shared libraries rather than static
+libraries. The options @option{-static} and @option{-shared} can
+also be used for RTPs (@pxref{Link Options}); @option{-static}
+is the default.
-@item -mbranch-expensive
-@opindex mbranch-expensive
-Pretend that branches are expensive. This is for experimenting with
-code generation only.
+@item -Bstatic
+@itemx -Bdynamic
+@opindex Bstatic
+@opindex Bdynamic
+These options are passed down to the linker. They are defined for
+compatibility with Diab.
+
+@item -Xbind-lazy
+@opindex Xbind-lazy
+Enable lazy binding of function calls. This option is equivalent to
+@option{-Wl,-z,now} and is defined for compatibility with Diab.
+
+@item -Xbind-now
+@opindex Xbind-now
+Disable lazy binding of function calls. This option is the default and
+is defined for compatibility with Diab.
+@end table
-@item -mbranch-cheap
-@opindex mbranch-cheap
-Do not pretend that branches are expensive. This is the default.
+@node x86-64 Options
+@subsection x86-64 Options
+@cindex x86-64 options
-@item -msplit
-@opindex msplit
-Generate code for a system with split I&D.
+These are listed under @xref{i386 and x86-64 Options}.
-@item -mno-split
-@opindex mno-split
-Generate code for a system without split I&D. This is the default.
+@node i386 and x86-64 Windows Options
+@subsection i386 and x86-64 Windows Options
+@cindex i386 and x86-64 Windows Options
-@item -munix-asm
-@opindex munix-asm
-Use Unix assembler syntax. This is the default when configured for
-@samp{pdp11-*-bsd}.
+These additional options are available for Windows targets:
-@item -mdec-asm
-@opindex mdec-asm
-Use DEC assembler syntax. This is the default when configured for any
-PDP-11 target other than @samp{pdp11-*-bsd}.
+@table @gcctabopt
+@item -mconsole
+@opindex mconsole
+This option is available for Cygwin and MinGW targets. It
+specifies that a console application is to be generated, by
+instructing the linker to set the PE header subsystem type
+required for console applications.
+This is the default behaviour for Cygwin and MinGW targets.
+
+@item -mcygwin
+@opindex mcygwin
+This option is available for Cygwin targets. It specifies that
+the Cygwin internal interface is to be used for predefined
+preprocessor macros, C runtime libraries and related linker
+paths and options. For Cygwin targets this is the default behaviour.
+This option is deprecated and will be removed in a future release.
+
+@item -mno-cygwin
+@opindex mno-cygwin
+This option is available for Cygwin targets. It specifies that
+the MinGW internal interface is to be used instead of Cygwin's, by
+setting MinGW-related predefined macros and linker paths and default
+library options.
+This option is deprecated and will be removed in a future release.
+
+@item -mdll
+@opindex mdll
+This option is available for Cygwin and MinGW targets. It
+specifies that a DLL - a dynamic link library - is to be
+generated, enabling the selection of the required runtime
+startup object and entry point.
+
+@item -mnop-fun-dllimport
+@opindex mnop-fun-dllimport
+This option is available for Cygwin and MinGW targets. It
+specifies that the dllimport attribute should be ignored.
+
+@item -mthread
+@opindex mthread
+This option is available for MinGW targets. It specifies
+that MinGW-specific thread support is to be used.
+
+@item -mwin32
+@opindex mwin32
+This option is available for Cygwin and MinGW targets. It
+specifies that the typical Windows pre-defined macros are to
+be set in the pre-processor, but does not influence the choice
+of runtime library/startup code.
+
+@item -mwindows
+@opindex mwindows
+This option is available for Cygwin and MinGW targets. It
+specifies that a GUI application is to be generated by
+instructing the linker to set the PE header subsystem type
+appropriately.
@end table
+See also under @ref{i386 and x86-64 Options} for standard options.
+
@node Xstormy16 Options
@subsection Xstormy16 Options
@cindex Xstormy16 Options
@subsection Xtensa Options
@cindex Xtensa Options
-The Xtensa architecture is designed to support many different
-configurations. The compiler's default options can be set to match a
-particular Xtensa configuration by copying a configuration file into the
-GCC sources when building GCC@. The options below may be used to
-override the default options.
+These options are supported for Xtensa targets:
@table @gcctabopt
-@item -mbig-endian
-@itemx -mlittle-endian
-@opindex mbig-endian
-@opindex mlittle-endian
-Specify big-endian or little-endian byte ordering for the target Xtensa
-processor.
-
-@item -mdensity
-@itemx -mno-density
-@opindex mdensity
-@opindex mno-density
-Enable or disable use of the optional Xtensa code density instructions.
-
-@item -mmac16
-@itemx -mno-mac16
-@opindex mmac16
-@opindex mno-mac16
-Enable or disable use of the Xtensa MAC16 option. When enabled, GCC
-will generate MAC16 instructions from standard C code, with the
-limitation that it will use neither the MR register file nor any
-instruction that operates on the MR registers. When this option is
-disabled, GCC will translate 16-bit multiply/accumulate operations to a
-combination of core instructions and library calls, depending on whether
-any other multiplier options are enabled.
-
-@item -mmul16
-@itemx -mno-mul16
-@opindex mmul16
-@opindex mno-mul16
-Enable or disable use of the 16-bit integer multiplier option. When
-enabled, the compiler will generate 16-bit multiply instructions for
-multiplications of 16 bits or smaller in standard C code. When this
-option is disabled, the compiler will either use 32-bit multiply or
-MAC16 instructions if they are available or generate library calls to
-perform the multiply operations using shifts and adds.
-
-@item -mmul32
-@itemx -mno-mul32
-@opindex mmul32
-@opindex mno-mul32
-Enable or disable use of the 32-bit integer multiplier option. When
-enabled, the compiler will generate 32-bit multiply instructions for
-multiplications of 32 bits or smaller in standard C code. When this
-option is disabled, the compiler will generate library calls to perform
-the multiply operations using either shifts and adds or 16-bit multiply
-instructions if they are available.
-
-@item -mnsa
-@itemx -mno-nsa
-@opindex mnsa
-@opindex mno-nsa
-Enable or disable use of the optional normalization shift amount
-(@code{NSA}) instructions to implement the built-in @code{ffs} function.
-
-@item -mminmax
-@itemx -mno-minmax
-@opindex mminmax
-@opindex mno-minmax
-Enable or disable use of the optional minimum and maximum value
-instructions.
-
-@item -msext
-@itemx -mno-sext
-@opindex msext
-@opindex mno-sext
-Enable or disable use of the optional sign extend (@code{SEXT})
-instruction.
-
-@item -mbooleans
-@itemx -mno-booleans
-@opindex mbooleans
-@opindex mno-booleans
-Enable or disable support for the boolean register file used by Xtensa
-coprocessors. This is not typically useful by itself but may be
-required for other options that make use of the boolean registers (e.g.,
-the floating-point option).
-
-@item -mhard-float
-@itemx -msoft-float
-@opindex mhard-float
-@opindex msoft-float
-Enable or disable use of the floating-point option. When enabled, GCC
-generates floating-point instructions for 32-bit @code{float}
-operations. When this option is disabled, GCC generates library calls
-to emulate 32-bit floating-point operations using integer instructions.
-Regardless of this option, 64-bit @code{double} operations are always
-emulated with calls to library functions.
+@item -mconst16
+@itemx -mno-const16
+@opindex mconst16
+@opindex mno-const16
+Enable or disable use of @code{CONST16} instructions for loading
+constant values. The @code{CONST16} instruction is currently not a
+standard option from Tensilica. When enabled, @code{CONST16}
+instructions are always used in place of the standard @code{L32R}
+instructions. The use of @code{CONST16} is enabled by default only if
+the @code{L32R} instruction is not available.
@item -mfused-madd
@itemx -mno-fused-madd
every cross-file call, not just those that really will be out of range.
@end table
+@node zSeries Options
+@subsection zSeries Options
+@cindex zSeries options
+
+These are listed under @xref{S/390 and zSeries Options}.
+
@node Code Gen Options
@section Options for Code Generation Conventions
@cindex code generation conventions
it.
@table @gcctabopt
+@item -fbounds-check
+@opindex fbounds-check
+For front-ends that support it, generate additional code to check that
+indices used to access arrays are within the declared range. This is
+currently only supported by the Java and Fortran front-ends, where
+this option defaults to true and false respectively.
+
+@item -ftrapv
+@opindex ftrapv
+This option generates traps for signed overflow on addition, subtraction,
+multiplication operations.
+
+@item -fwrapv
+@opindex fwrapv
+This option instructs the compiler to assume that signed arithmetic
+overflow of addition, subtraction and multiplication wraps around
+using twos-complement representation. This flag enables some optimizations
+and disables others. This option is enabled by default for the Java
+front-end, as required by the Java language specification.
+
@item -fexceptions
@opindex fexceptions
Enable exception handling. Generates extra code needed to propagate
that needs this handling would enable it on your behalf.
@item -fasynchronous-unwind-tables
-@opindex funwind-tables
+@opindex fasynchronous-unwind-tables
Generate unwind table in dwarf2 format, if supported by target machine. The
table is exact at each instruction boundary, so it can be used for stack
unwinding from asynchronous events (such as debugger or garbage collector).
code that is not binary compatible with code generated without that switch.
Use it to conform to a non-default application binary interface.
-@item -fshared-data
-@opindex fshared-data
-Requests that the data and non-@code{const} variables of this
-compilation be shared data rather than private data. The distinction
-makes sense only on certain operating systems, where shared data is
-shared between processes running the same program, while private data
-exists in one copy per process.
-
@item -fno-common
@opindex fno-common
-In C, allocate even uninitialized global variables in the data section of the
-object file, rather than generating them as common blocks. This has the
-effect that if the same variable is declared (without @code{extern}) in
-two different compilations, you will get an error when you link them.
-The only reason this might be useful is if you wish to verify that the
-program will work on other systems which always work this way.
+In C code, controls the placement of uninitialized global variables.
+Unix C compilers have traditionally permitted multiple definitions of
+such variables in different compilation units by placing the variables
+in a common block.
+This is the behavior specified by @option{-fcommon}, and is the default
+for GCC on most targets.
+On the other hand, this behavior is not required by ISO C, and on some
+targets may carry a speed or code size penalty on variable references.
+The @option{-fno-common} option specifies that the compiler should place
+uninitialized global variables in the data section of the object file,
+rather than generating them as common blocks.
+This has the effect that if the same variable is declared
+(without @code{extern}) in two different compilations,
+you will get a multiple-definition error when you link them.
+In this case, you must compile with @option{-fcommon} instead.
+Compiling with @option{-fno-common} is useful on targets for which
+it provides better performance, or if you wish to verify that the
+program will work on other systems which always treat uninitialized
+variable declarations this way.
@item -fno-ident
@opindex fno-ident
Ignore the @samp{#ident} directive.
-@item -fno-gnu-linker
-@opindex fno-gnu-linker
-Do not output global initializations (such as C++ constructors and
-destructors) in the form used by the GNU linker (on systems where the GNU
-linker is the standard method of handling them). Use this option when
-you want to use a non-GNU linker, which also requires using the
-@command{collect2} program to make sure the system linker includes
-constructors and destructors. (@command{collect2} is included in the GCC
-distribution.) For systems which @emph{must} use @command{collect2}, the
-compiler driver @command{gcc} is configured to do this automatically.
-
@item -finhibit-size-directive
@opindex finhibit-size-directive
Don't output a @code{.size} assembler directive, or anything else that
extra information to be omitted and is useful when comparing two assembler
files.
-@item -fvolatile
-@opindex fvolatile
-Consider all memory references through pointers to be volatile.
-
-@item -fvolatile-global
-@opindex fvolatile-global
-Consider all memory references to extern and global data items to
-be volatile. GCC does not consider static data items to be volatile
-because of this switch.
-
-@item -fvolatile-static
-@opindex fvolatile-static
-Consider all memory references to static data to be volatile.
+@item -frecord-gcc-switches
+@opindex frecord-gcc-switches
+This switch causes the command line that was used to invoke the
+compiler to be recorded into the object file that is being created.
+This switch is only implemented on some targets and the exact format
+of the recording is target and binary file format dependent, but it
+usually takes the form of a section containing ASCII text. This
+switch is related to the @option{-fverbose-asm} switch, but that
+switch only records information in the assembler output file as
+comments, so it never reaches the object file.
@item -fpic
@opindex fpic
the GOT size for the linked executable exceeds a machine-specific
maximum size, you get an error message from the linker indicating that
@option{-fpic} does not work; in that case, recompile with @option{-fPIC}
-instead. (These maximums are 16k on the m88k, 8k on the Sparc, and 32k
+instead. (These maximums are 8k on the SPARC and 32k
on the m68k and RS/6000. The 386 has no such limit.)
Position-independent code requires special support, and therefore works
but not for the Sun 386i. Code generated for the IBM RS/6000 is always
position-independent.
+When this flag is set, the macros @code{__pic__} and @code{__PIC__}
+are defined to 1.
+
@item -fPIC
@opindex fPIC
If supported for the target machine, emit position-independent code,
suitable for dynamic linking and avoiding any limit on the size of the
-global offset table. This option makes a difference on the m68k, m88k,
-and the Sparc.
+global offset table. This option makes a difference on the m68k,
+PowerPC and SPARC@.
Position-independent code requires special support, and therefore works
only on certain machines.
+When this flag is set, the macros @code{__pic__} and @code{__PIC__}
+are defined to 2.
+
+@item -fpie
+@itemx -fPIE
+@opindex fpie
+@opindex fPIE
+These options are similar to @option{-fpic} and @option{-fPIC}, but
+generated position independent code can be only linked into executables.
+Usually these options are used when @option{-pie} GCC option will be
+used during linking.
+
+@option{-fpie} and @option{-fPIE} both define the macros
+@code{__pie__} and @code{__PIE__}. The macros have the value 1
+for @option{-fpie} and 2 for @option{-fPIE}.
+
+@item -fno-jump-tables
+@opindex fno-jump-tables
+Do not use jump tables for switch statements even where it would be
+more efficient than other code generation strategies. This option is
+of use in conjunction with @option{-fpic} or @option{-fPIC} for
+building code which forms part of a dynamic linker and cannot
+reference the address of a jump table. On some targets, jump tables
+do not require a GOT and this option is not needed.
+
@item -ffixed-@var{reg}
@opindex ffixed
Treat the register named @var{reg} as a fixed register; generated code
This flag does not have a negative form, because it specifies a
three-way choice.
-@item -fpack-struct
+@item -fpack-struct[=@var{n}]
@opindex fpack-struct
-Pack all structure members together without holes.
+Without a value specified, pack all structure members together without
+holes. When a value is specified (which must be a small power of two), pack
+structure members according to this value, representing the maximum
+alignment (that is, objects with default alignment requirements larger than
+this will be output potentially unaligned at the next fitting location.
@strong{Warning:} the @option{-fpack-struct} switch causes GCC to generate
code that is not binary compatible with code generated without that switch.
-Additionally, it makes the code suboptimial.
+Additionally, it makes the code suboptimal.
Use it to conform to a non-default application binary interface.
@item -finstrument-functions
function, so the call site information may not be available to the
profiling functions otherwise.)
-@example
+@smallexample
void __cyg_profile_func_enter (void *this_fn,
void *call_site);
void __cyg_profile_func_exit (void *this_fn,
void *call_site);
-@end example
+@end smallexample
The first argument is the address of the start of the current function,
which may be looked up exactly in the symbol table.
cannot safely be called (perhaps signal handlers, if the profiling
routines generate output or allocate memory).
+@item -finstrument-functions-exclude-file-list=@var{file},@var{file},@dots{}
+@opindex finstrument-functions-exclude-file-list
+
+Set the list of functions that are excluded from instrumentation (see
+the description of @code{-finstrument-functions}). If the file that
+contains a function definition matches with one of @var{file}, then
+that function is not instrumented. The match is done on substrings:
+if the @var{file} parameter is a substring of the file name, it is
+considered to be a match.
+
+For example,
+@code{-finstrument-functions-exclude-file-list=/bits/stl,include/sys}
+will exclude any inline function defined in files whose pathnames
+contain @code{/bits/stl} or @code{include/sys}.
+
+If, for some reason, you want to include letter @code{','} in one of
+@var{sym}, write @code{'\,'}. For example,
+@code{-finstrument-functions-exclude-file-list='\,\,tmp'}
+(note the single quote surrounding the option).
+
+@item -finstrument-functions-exclude-function-list=@var{sym},@var{sym},@dots{}
+@opindex finstrument-functions-exclude-function-list
+
+This is similar to @code{-finstrument-functions-exclude-file-list},
+but this option sets the list of function names to be excluded from
+instrumentation. The function name to be matched is its user-visible
+name, such as @code{vector<int> blah(const vector<int> &)}, not the
+internal mangled name (e.g., @code{_Z4blahRSt6vectorIiSaIiEE}). The
+match is done on substrings: if the @var{sym} parameter is a substring
+of the function name, it is considered to be a match.
+
@item -fstack-check
@opindex fstack-check
Generate code to verify that you do not go beyond the boundary of the
detected on nearly all systems if there is only one stack.
Note that this switch does not actually cause checking to be done; the
-operating system must do that. The switch causes generation of code
-to ensure that the operating system sees the stack being extended.
+operating system or the language runtime must do that. The switch causes
+generation of code to ensure that they see the stack being extended.
+
+You can additionally specify a string parameter: @code{no} means no
+checking, @code{generic} means force the use of old-style checking,
+@code{specific} means use the best checking method and is equivalent
+to bare @option{-fstack-check}.
+
+Old-style checking is a generic mechanism that requires no specific
+target support in the compiler but comes with the following drawbacks:
+
+@enumerate
+@item
+Modified allocation strategy for large objects: they will always be
+allocated dynamically if their size exceeds a fixed threshold.
+
+@item
+Fixed limit on the size of the static frame of functions: when it is
+topped by a particular function, stack checking is not reliable and
+a warning is issued by the compiler.
+
+@item
+Inefficiency: because of both the modified allocation strategy and the
+generic implementation, the performances of the code are hampered.
+@end enumerate
+
+Note that old-style stack checking is also the fallback method for
+@code{specific} if no target support has been added in the compiler.
@item -fstack-limit-register=@var{reg}
@itemx -fstack-limit-symbol=@var{sym}
@item -fargument-alias
@itemx -fargument-noalias
@itemx -fargument-noalias-global
+@itemx -fargument-noalias-anything
@opindex fargument-alias
@opindex fargument-noalias
@opindex fargument-noalias-global
+@opindex fargument-noalias-anything
Specify the possible relationships among parameters and between
parameters and global data.
each other, but may alias global storage.@*
@option{-fargument-noalias-global} specifies that arguments do not
alias each other and do not alias global storage.
+@option{-fargument-noalias-anything} specifies that arguments do not
+alias any other storage.
Each language will automatically use whatever option is required by
the language standard. You should not need to use these options yourself.
generate code that is not binary compatible with code generated without that
switch. Use it to conform to a non-default application binary interface.
Not all targets provide complete support for this switch.
+
+@item -ftls-model=@var{model}
+@opindex ftls-model
+Alter the thread-local storage model to be used (@pxref{Thread-Local}).
+The @var{model} argument should be one of @code{global-dynamic},
+@code{local-dynamic}, @code{initial-exec} or @code{local-exec}.
+
+The default without @option{-fpic} is @code{initial-exec}; with
+@option{-fpic} the default is @code{global-dynamic}.
+
+@item -fvisibility=@var{default|internal|hidden|protected}
+@opindex fvisibility
+Set the default ELF image symbol visibility to the specified option---all
+symbols will be marked with this unless overridden within the code.
+Using this feature can very substantially improve linking and
+load times of shared object libraries, produce more optimized
+code, provide near-perfect API export and prevent symbol clashes.
+It is @strong{strongly} recommended that you use this in any shared objects
+you distribute.
+
+Despite the nomenclature, @code{default} always means public ie;
+available to be linked against from outside the shared object.
+@code{protected} and @code{internal} are pretty useless in real-world
+usage so the only other commonly used option will be @code{hidden}.
+The default if @option{-fvisibility} isn't specified is
+@code{default}, i.e., make every
+symbol public---this causes the same behavior as previous versions of
+GCC@.
+
+A good explanation of the benefits offered by ensuring ELF
+symbols have the correct visibility is given by ``How To Write
+Shared Libraries'' by Ulrich Drepper (which can be found at
+@w{@uref{http://people.redhat.com/~drepper/}})---however a superior
+solution made possible by this option to marking things hidden when
+the default is public is to make the default hidden and mark things
+public. This is the norm with DLL's on Windows and with @option{-fvisibility=hidden}
+and @code{__attribute__ ((visibility("default")))} instead of
+@code{__declspec(dllexport)} you get almost identical semantics with
+identical syntax. This is a great boon to those working with
+cross-platform projects.
+
+For those adding visibility support to existing code, you may find
+@samp{#pragma GCC visibility} of use. This works by you enclosing
+the declarations you wish to set visibility for with (for example)
+@samp{#pragma GCC visibility push(hidden)} and
+@samp{#pragma GCC visibility pop}.
+Bear in mind that symbol visibility should be viewed @strong{as
+part of the API interface contract} and thus all new code should
+always specify visibility when it is not the default ie; declarations
+only for use within the local DSO should @strong{always} be marked explicitly
+as hidden as so to avoid PLT indirection overheads---making this
+abundantly clear also aids readability and self-documentation of the code.
+Note that due to ISO C++ specification requirements, operator new and
+operator delete must always be of default visibility.
+
+Be aware that headers from outside your project, in particular system
+headers and headers from any other library you use, may not be
+expecting to be compiled with visibility other than the default. You
+may need to explicitly say @samp{#pragma GCC visibility push(default)}
+before including any such headers.
+
+@samp{extern} declarations are not affected by @samp{-fvisibility}, so
+a lot of code can be recompiled with @samp{-fvisibility=hidden} with
+no modifications. However, this means that calls to @samp{extern}
+functions with no explicit visibility will use the PLT, so it is more
+effective to use @samp{__attribute ((visibility))} and/or
+@samp{#pragma GCC visibility} to tell the compiler which @samp{extern}
+declarations should be treated as hidden.
+
+Note that @samp{-fvisibility} does affect C++ vague linkage
+entities. This means that, for instance, an exception class that will
+be thrown between DSOs must be explicitly marked with default
+visibility so that the @samp{type_info} nodes will be unified between
+the DSOs.
+
+An overview of these techniques, their benefits and how to use them
+is at @w{@uref{http://gcc.gnu.org/wiki/Visibility}}.
+
@end table
@c man end
@cindex environment variables
@c man begin ENVIRONMENT
-
This section describes several environment variables that affect how GCC
operates. Some of them work by specifying directories or prefixes to use
when searching for various kinds of files. Some are used to specify other
national conventions. GCC inspects the locale categories
@env{LC_CTYPE} and @env{LC_MESSAGES} if it has been configured to do
so. These locale categories can be set to any value supported by your
-installation. A typical value is @samp{en_UK} for English in the United
-Kingdom.
+installation. A typical value is @samp{en_GB.UTF-8} for English in the United
+Kingdom encoded in UTF-8.
The @env{LC_CTYPE} environment variable specifies character
classification. GCC uses it to determine the character boundaries in
tries looking in the usual places for the subprogram.
The default value of @env{GCC_EXEC_PREFIX} is
-@file{@var{prefix}/lib/gcc-lib/} where @var{prefix} is the value
+@file{@var{prefix}/lib/gcc/} where @var{prefix} is the prefix to
+the installed compiler. In many cases @var{prefix} is the value
of @code{prefix} when you ran the @file{configure} script.
Other prefixes specified with @option{-B} take precedence over this prefix.
In addition, the prefix is used in an unusual way in finding the
directories to search for header files. For each of the standard
-directories whose name normally begins with @samp{/usr/local/lib/gcc-lib}
+directories whose name normally begins with @samp{/usr/local/lib/gcc}
(more precisely, with the value of @env{GCC_INCLUDE_DIR}), GCC tries
replacing that beginning with the specified prefix to produce an
alternate directory name. Thus, with @option{-Bfoo/}, GCC will search
@file{foo/bar} where it would normally search @file{/usr/local/lib/bar}.
These alternate directories are searched first; the standard directories
-come next.
+come next. If a standard directory begins with the configured
+@var{prefix} then the value of @var{prefix} is replaced by
+@env{GCC_EXEC_PREFIX} when looking for header files.
@item COMPILER_PATH
@findex COMPILER_PATH
@c man end
+@node Precompiled Headers
+@section Using Precompiled Headers
+@cindex precompiled headers
+@cindex speed of compilation
+
+Often large projects have many header files that are included in every
+source file. The time the compiler takes to process these header files
+over and over again can account for nearly all of the time required to
+build the project. To make builds faster, GCC allows users to
+`precompile' a header file; then, if builds can use the precompiled
+header file they will be much faster.
+
+To create a precompiled header file, simply compile it as you would any
+other file, if necessary using the @option{-x} option to make the driver
+treat it as a C or C++ header file. You will probably want to use a
+tool like @command{make} to keep the precompiled header up-to-date when
+the headers it contains change.
+
+A precompiled header file will be searched for when @code{#include} is
+seen in the compilation. As it searches for the included file
+(@pxref{Search Path,,Search Path,cpp,The C Preprocessor}) the
+compiler looks for a precompiled header in each directory just before it
+looks for the include file in that directory. The name searched for is
+the name specified in the @code{#include} with @samp{.gch} appended. If
+the precompiled header file can't be used, it is ignored.
+
+For instance, if you have @code{#include "all.h"}, and you have
+@file{all.h.gch} in the same directory as @file{all.h}, then the
+precompiled header file will be used if possible, and the original
+header will be used otherwise.
+
+Alternatively, you might decide to put the precompiled header file in a
+directory and use @option{-I} to ensure that directory is searched
+before (or instead of) the directory containing the original header.
+Then, if you want to check that the precompiled header file is always
+used, you can put a file of the same name as the original header in this
+directory containing an @code{#error} command.
+
+This also works with @option{-include}. So yet another way to use
+precompiled headers, good for projects not designed with precompiled
+header files in mind, is to simply take most of the header files used by
+a project, include them from another header file, precompile that header
+file, and @option{-include} the precompiled header. If the header files
+have guards against multiple inclusion, they will be skipped because
+they've already been included (in the precompiled header).
+
+If you need to precompile the same header file for different
+languages, targets, or compiler options, you can instead make a
+@emph{directory} named like @file{all.h.gch}, and put each precompiled
+header in the directory, perhaps using @option{-o}. It doesn't matter
+what you call the files in the directory, every precompiled header in
+the directory will be considered. The first precompiled header
+encountered in the directory that is valid for this compilation will
+be used; they're searched in no particular order.
+
+There are many other possibilities, limited only by your imagination,
+good sense, and the constraints of your build system.
+
+A precompiled header file can be used only when these conditions apply:
+
+@itemize
+@item
+Only one precompiled header can be used in a particular compilation.
+
+@item
+A precompiled header can't be used once the first C token is seen. You
+can have preprocessor directives before a precompiled header; you can
+even include a precompiled header from inside another header, so long as
+there are no C tokens before the @code{#include}.
+
+@item
+The precompiled header file must be produced for the same language as
+the current compilation. You can't use a C precompiled header for a C++
+compilation.
+
+@item
+The precompiled header file must have been produced by the same compiler
+binary as the current compilation is using.
+
+@item
+Any macros defined before the precompiled header is included must
+either be defined in the same way as when the precompiled header was
+generated, or must not affect the precompiled header, which usually
+means that they don't appear in the precompiled header at all.
+
+The @option{-D} option is one way to define a macro before a
+precompiled header is included; using a @code{#define} can also do it.
+There are also some options that define macros implicitly, like
+@option{-O} and @option{-Wdeprecated}; the same rule applies to macros
+defined this way.
+
+@item If debugging information is output when using the precompiled
+header, using @option{-g} or similar, the same kind of debugging information
+must have been output when building the precompiled header. However,
+a precompiled header built using @option{-g} can be used in a compilation
+when no debugging information is being output.
+
+@item The same @option{-m} options must generally be used when building
+and using the precompiled header. @xref{Submodel Options},
+for any cases where this rule is relaxed.
+
+@item Each of the following options must be the same when building and using
+the precompiled header:
+
+@gccoptlist{-fexceptions}
+
+@item
+Some other command-line options starting with @option{-f},
+@option{-p}, or @option{-O} must be defined in the same way as when
+the precompiled header was generated. At present, it's not clear
+which options are safe to change and which are not; the safest choice
+is to use exactly the same options when generating and using the
+precompiled header. The following are known to be safe:
+
+@gccoptlist{-fmessage-length= -fpreprocessed -fsched-interblock @gol
+-fsched-spec -fsched-spec-load -fsched-spec-load-dangerous @gol
+-fsched-verbose=<number> -fschedule-insns -fvisibility= @gol
+-pedantic-errors}
+
+@end itemize
+
+For all of these except the last, the compiler will automatically
+ignore the precompiled header if the conditions aren't met. If you
+find an option combination that doesn't work and doesn't cause the
+precompiled header to be ignored, please consider filing a bug report,
+see @ref{Bugs}.
+
+If you do use differing options when generating and using the
+precompiled header, the actual behavior will be a mixture of the
+behavior for the options. For instance, if you use @option{-g} to
+generate the precompiled header but not when using it, you may or may
+not get debugging information for routines in the precompiled header.
+
@node Running Protoize
@section Running Protoize
applies only to @code{protoize}.
@item -c @var{compilation-options}
-Use @var{compilation-options} as the options when running @code{gcc} to
+Use @var{compilation-options} as the options when running @command{gcc} to
produce the @samp{.X} files. The special option @option{-aux-info} is
-always passed in addition, to tell @code{gcc} to write a @samp{.X} file.
+always passed in addition, to tell @command{gcc} to write a @samp{.X} file.
Note that the compilation options must be given as a single argument to
@code{protoize} or @code{unprotoize}. If you want to specify several
-@code{gcc} options, you must quote the entire set of compilation options
+@command{gcc} options, you must quote the entire set of compilation options
to make them a single word in the shell.
-There are certain @code{gcc} arguments that you cannot use, because they
+There are certain @command{gcc} arguments that you cannot use, because they
would produce the wrong kind of output. These include @option{-g},
@option{-O}, @option{-c}, @option{-S}, and @option{-o} If you include these in
the @var{compilation-options}, they are ignored.
Work quietly. Most warnings are suppressed.
@item -v
-Print the version number, just like @option{-v} for @code{gcc}.
+Print the version number, just like @option{-v} for @command{gcc}.
@end table
If you need special compiler options to compile one of your program's
source files, then you should generate that file's @samp{.X} file
-specially, by running @code{gcc} on that source file with the
+specially, by running @command{gcc} on that source file with the
appropriate options and the option @option{-aux-info}. Then run
@code{protoize} on the entire set of files. @code{protoize} will use
the existing @samp{.X} file because it is newer than the source file.
For example:
-@example
+@smallexample
gcc -Dfoo=bar file1.c -aux-info file1.X
protoize *.c
-@end example
+@end smallexample
@noindent
You need to include the special files along with the rest in the
projects / msp430-gcc.git / blobdiff