+++ /dev/null
-/* Data flow analysis for GNU compiler.
- Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001 Free Software Foundation, Inc.
-
-This file is part of GCC.
-
-GCC is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 2, or (at your option) any later
-version.
-
-GCC is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY; without even the implied warranty of MERCHANTABILITY or
-FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-for more details.
-
-You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
-
-/* This file contains the data flow analysis pass of the compiler. It
- computes data flow information which tells combine_instructions
- which insns to consider combining and controls register allocation.
-
- Additional data flow information that is too bulky to record is
- generated during the analysis, and is used at that time to create
- autoincrement and autodecrement addressing.
-
- The first step is dividing the function into basic blocks.
- find_basic_blocks does this. Then life_analysis determines
- where each register is live and where it is dead.
-
- ** find_basic_blocks **
-
- find_basic_blocks divides the current function's rtl into basic
- blocks and constructs the CFG. The blocks are recorded in the
- basic_block_info array; the CFG exists in the edge structures
- referenced by the blocks.
-
- find_basic_blocks also finds any unreachable loops and deletes them.
-
- ** life_analysis **
-
- life_analysis is called immediately after find_basic_blocks.
- It uses the basic block information to determine where each
- hard or pseudo register is live.
-
- ** live-register info **
-
- The information about where each register is live is in two parts:
- the REG_NOTES of insns, and the vector basic_block->global_live_at_start.
-
- basic_block->global_live_at_start has an element for each basic
- block, and the element is a bit-vector with a bit for each hard or
- pseudo register. The bit is 1 if the register is live at the
- beginning of the basic block.
-
- Two types of elements can be added to an insn's REG_NOTES.
- A REG_DEAD note is added to an insn's REG_NOTES for any register
- that meets both of two conditions: The value in the register is not
- needed in subsequent insns and the insn does not replace the value in
- the register (in the case of multi-word hard registers, the value in
- each register must be replaced by the insn to avoid a REG_DEAD note).
-
- In the vast majority of cases, an object in a REG_DEAD note will be
- used somewhere in the insn. The (rare) exception to this is if an
- insn uses a multi-word hard register and only some of the registers are
- needed in subsequent insns. In that case, REG_DEAD notes will be
- provided for those hard registers that are not subsequently needed.
- Partial REG_DEAD notes of this type do not occur when an insn sets
- only some of the hard registers used in such a multi-word operand;
- omitting REG_DEAD notes for objects stored in an insn is optional and
- the desire to do so does not justify the complexity of the partial
- REG_DEAD notes.
-
- REG_UNUSED notes are added for each register that is set by the insn
- but is unused subsequently (if every register set by the insn is unused
- and the insn does not reference memory or have some other side-effect,
- the insn is deleted instead). If only part of a multi-word hard
- register is used in a subsequent insn, REG_UNUSED notes are made for
- the parts that will not be used.
-
- To determine which registers are live after any insn, one can
- start from the beginning of the basic block and scan insns, noting
- which registers are set by each insn and which die there.
-
- ** Other actions of life_analysis **
-
- life_analysis sets up the LOG_LINKS fields of insns because the
- information needed to do so is readily available.
-
- life_analysis deletes insns whose only effect is to store a value
- that is never used.
-
- life_analysis notices cases where a reference to a register as
- a memory address can be combined with a preceding or following
- incrementation or decrementation of the register. The separate
- instruction to increment or decrement is deleted and the address
- is changed to a POST_INC or similar rtx.
-
- Each time an incrementing or decrementing address is created,
- a REG_INC element is added to the insn's REG_NOTES list.
-
- life_analysis fills in certain vectors containing information about
- register usage: REG_N_REFS, REG_N_DEATHS, REG_N_SETS, REG_LIVE_LENGTH,
- REG_N_CALLS_CROSSED and REG_BASIC_BLOCK.
-
- life_analysis sets current_function_sp_is_unchanging if the function
- doesn't modify the stack pointer. */
-
-/* TODO:
-
- Split out from life_analysis:
- - local property discovery (bb->local_live, bb->local_set)
- - global property computation
- - log links creation
- - pre/post modify transformation
-*/
-\f
-#include "config.h"
-#include "system.h"
-#include "tree.h"
-#include "rtl.h"
-#include "tm_p.h"
-#include "hard-reg-set.h"
-#include "basic-block.h"
-#include "insn-config.h"
-#include "regs.h"
-#include "flags.h"
-#include "output.h"
-#include "function.h"
-#include "except.h"
-#include "toplev.h"
-#include "recog.h"
-#include "expr.h"
-#include "ssa.h"
-#include "timevar.h"
-
-#include "obstack.h"
-#include "splay-tree.h"
-
-#define obstack_chunk_alloc xmalloc
-#define obstack_chunk_free free
-
-/* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
- the stack pointer does not matter. The value is tested only in
- functions that have frame pointers.
- No definition is equivalent to always zero. */
-#ifndef EXIT_IGNORE_STACK
-#define EXIT_IGNORE_STACK 0
-#endif
-
-#ifndef HAVE_epilogue
-#define HAVE_epilogue 0
-#endif
-#ifndef HAVE_prologue
-#define HAVE_prologue 0
-#endif
-#ifndef HAVE_sibcall_epilogue
-#define HAVE_sibcall_epilogue 0
-#endif
-
-#ifndef LOCAL_REGNO
-#define LOCAL_REGNO(REGNO) 0
-#endif
-#ifndef EPILOGUE_USES
-#define EPILOGUE_USES(REGNO) 0
-#endif
-#ifndef EH_USES
-#define EH_USES(REGNO) 0
-#endif
-
-#ifdef HAVE_conditional_execution
-#ifndef REVERSE_CONDEXEC_PREDICATES_P
-#define REVERSE_CONDEXEC_PREDICATES_P(x, y) ((x) == reverse_condition (y))
-#endif
-#endif
-
-/* Nonzero if the second flow pass has completed. */
-int flow2_completed;
-
-/* Maximum register number used in this function, plus one. */
-
-int max_regno;
-
-/* Indexed by n, giving various register information */
-
-varray_type reg_n_info;
-
-/* Size of a regset for the current function,
- in (1) bytes and (2) elements. */
-
-int regset_bytes;
-int regset_size;
-
-/* Regset of regs live when calls to `setjmp'-like functions happen. */
-/* ??? Does this exist only for the setjmp-clobbered warning message? */
-
-regset regs_live_at_setjmp;
-
-/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
- that have to go in the same hard reg.
- The first two regs in the list are a pair, and the next two
- are another pair, etc. */
-rtx regs_may_share;
-
-/* Callback that determines if it's ok for a function to have no
- noreturn attribute. */
-int (*lang_missing_noreturn_ok_p) PARAMS ((tree));
-
-/* Set of registers that may be eliminable. These are handled specially
- in updating regs_ever_live. */
-
-static HARD_REG_SET elim_reg_set;
-
-/* Holds information for tracking conditional register life information. */
-struct reg_cond_life_info
-{
- /* A boolean expression of conditions under which a register is dead. */
- rtx condition;
- /* Conditions under which a register is dead at the basic block end. */
- rtx orig_condition;
-
- /* A boolean expression of conditions under which a register has been
- stored into. */
- rtx stores;
-
- /* ??? Could store mask of bytes that are dead, so that we could finally
- track lifetimes of multi-word registers accessed via subregs. */
-};
-
-/* For use in communicating between propagate_block and its subroutines.
- Holds all information needed to compute life and def-use information. */
-
-struct propagate_block_info
-{
- /* The basic block we're considering. */
- basic_block bb;
-
- /* Bit N is set if register N is conditionally or unconditionally live. */
- regset reg_live;
-
- /* Bit N is set if register N is set this insn. */
- regset new_set;
-
- /* Element N is the next insn that uses (hard or pseudo) register N
- within the current basic block; or zero, if there is no such insn. */
- rtx *reg_next_use;
-
- /* Contains a list of all the MEMs we are tracking for dead store
- elimination. */
- rtx mem_set_list;
-
- /* If non-null, record the set of registers set unconditionally in the
- basic block. */
- regset local_set;
-
- /* If non-null, record the set of registers set conditionally in the
- basic block. */
- regset cond_local_set;
-
-#ifdef HAVE_conditional_execution
- /* Indexed by register number, holds a reg_cond_life_info for each
- register that is not unconditionally live or dead. */
- splay_tree reg_cond_dead;
-
- /* Bit N is set if register N is in an expression in reg_cond_dead. */
- regset reg_cond_reg;
-#endif
-
- /* The length of mem_set_list. */
- int mem_set_list_len;
-
- /* Non-zero if the value of CC0 is live. */
- int cc0_live;
-
- /* Flags controling the set of information propagate_block collects. */
- int flags;
-};
-
-/* Maximum length of pbi->mem_set_list before we start dropping
- new elements on the floor. */
-#define MAX_MEM_SET_LIST_LEN 100
-
-/* Forward declarations */
-static int verify_wide_reg_1 PARAMS ((rtx *, void *));
-static void verify_wide_reg PARAMS ((int, basic_block));
-static void verify_local_live_at_start PARAMS ((regset, basic_block));
-static void notice_stack_pointer_modification_1 PARAMS ((rtx, rtx, void *));
-static void notice_stack_pointer_modification PARAMS ((rtx));
-static void mark_reg PARAMS ((rtx, void *));
-static void mark_regs_live_at_end PARAMS ((regset));
-static int set_phi_alternative_reg PARAMS ((rtx, int, int, void *));
-static void calculate_global_regs_live PARAMS ((sbitmap, sbitmap, int));
-static void propagate_block_delete_insn PARAMS ((basic_block, rtx));
-static rtx propagate_block_delete_libcall PARAMS ((rtx, rtx));
-static int insn_dead_p PARAMS ((struct propagate_block_info *,
- rtx, int, rtx));
-static int libcall_dead_p PARAMS ((struct propagate_block_info *,
- rtx, rtx));
-static void mark_set_regs PARAMS ((struct propagate_block_info *,
- rtx, rtx));
-static void mark_set_1 PARAMS ((struct propagate_block_info *,
- enum rtx_code, rtx, rtx,
- rtx, int));
-static int find_regno_partial PARAMS ((rtx *, void *));
-
-#ifdef HAVE_conditional_execution
-static int mark_regno_cond_dead PARAMS ((struct propagate_block_info *,
- int, rtx));
-static void free_reg_cond_life_info PARAMS ((splay_tree_value));
-static int flush_reg_cond_reg_1 PARAMS ((splay_tree_node, void *));
-static void flush_reg_cond_reg PARAMS ((struct propagate_block_info *,
- int));
-static rtx elim_reg_cond PARAMS ((rtx, unsigned int));
-static rtx ior_reg_cond PARAMS ((rtx, rtx, int));
-static rtx not_reg_cond PARAMS ((rtx));
-static rtx and_reg_cond PARAMS ((rtx, rtx, int));
-#endif
-#ifdef AUTO_INC_DEC
-static void attempt_auto_inc PARAMS ((struct propagate_block_info *,
- rtx, rtx, rtx, rtx, rtx));
-static void find_auto_inc PARAMS ((struct propagate_block_info *,
- rtx, rtx));
-static int try_pre_increment_1 PARAMS ((struct propagate_block_info *,
- rtx));
-static int try_pre_increment PARAMS ((rtx, rtx, HOST_WIDE_INT));
-#endif
-static void mark_used_reg PARAMS ((struct propagate_block_info *,
- rtx, rtx, rtx));
-static void mark_used_regs PARAMS ((struct propagate_block_info *,
- rtx, rtx, rtx));
-void dump_flow_info PARAMS ((FILE *));
-void debug_flow_info PARAMS ((void));
-static void add_to_mem_set_list PARAMS ((struct propagate_block_info *,
- rtx));
-static void invalidate_mems_from_autoinc PARAMS ((struct propagate_block_info *,
- rtx));
-static void invalidate_mems_from_set PARAMS ((struct propagate_block_info *,
- rtx));
-static void delete_dead_jumptables PARAMS ((void));
-static void clear_log_links PARAMS ((sbitmap));
-\f
-
-void
-check_function_return_warnings ()
-{
- if (warn_missing_noreturn
- && !TREE_THIS_VOLATILE (cfun->decl)
- && EXIT_BLOCK_PTR->pred == NULL
- && (lang_missing_noreturn_ok_p
- && !lang_missing_noreturn_ok_p (cfun->decl)))
- warning ("function might be possible candidate for attribute `noreturn'");
-
- /* If we have a path to EXIT, then we do return. */
- if (TREE_THIS_VOLATILE (cfun->decl)
- && EXIT_BLOCK_PTR->pred != NULL)
- warning ("`noreturn' function does return");
-
- /* If the clobber_return_insn appears in some basic block, then we
- do reach the end without returning a value. */
- else if (warn_return_type
- && cfun->x_clobber_return_insn != NULL
- && EXIT_BLOCK_PTR->pred != NULL)
- {
- int max_uid = get_max_uid ();
-
- /* If clobber_return_insn was excised by jump1, then renumber_insns
- can make max_uid smaller than the number still recorded in our rtx.
- That's fine, since this is a quick way of verifying that the insn
- is no longer in the chain. */
- if (INSN_UID (cfun->x_clobber_return_insn) < max_uid)
- {
- /* Recompute insn->block mapping, since the initial mapping is
- set before we delete unreachable blocks. */
- if (BLOCK_FOR_INSN (cfun->x_clobber_return_insn) != NULL)
- warning ("control reaches end of non-void function");
- }
- }
-}
-\f
-/* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
- note associated with the BLOCK. */
-
-rtx
-first_insn_after_basic_block_note (block)
- basic_block block;
-{
- rtx insn;
-
- /* Get the first instruction in the block. */
- insn = block->head;
-
- if (insn == NULL_RTX)
- return NULL_RTX;
- if (GET_CODE (insn) == CODE_LABEL)
- insn = NEXT_INSN (insn);
- if (!NOTE_INSN_BASIC_BLOCK_P (insn))
- abort ();
-
- return NEXT_INSN (insn);
-}
-\f
-/* Perform data flow analysis.
- F is the first insn of the function; FLAGS is a set of PROP_* flags
- to be used in accumulating flow info. */
-
-void
-life_analysis (f, file, flags)
- rtx f;
- FILE *file;
- int flags;
-{
-#ifdef ELIMINABLE_REGS
- int i;
- static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
-#endif
-
- /* Record which registers will be eliminated. We use this in
- mark_used_regs. */
-
- CLEAR_HARD_REG_SET (elim_reg_set);
-
-#ifdef ELIMINABLE_REGS
- for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
- SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
-#else
- SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
-#endif
-
- if (! optimize)
- flags &= ~(PROP_LOG_LINKS | PROP_AUTOINC | PROP_ALLOW_CFG_CHANGES);
-
- /* The post-reload life analysis have (on a global basis) the same
- registers live as was computed by reload itself. elimination
- Otherwise offsets and such may be incorrect.
-
- Reload will make some registers as live even though they do not
- appear in the rtl.
-
- We don't want to create new auto-incs after reload, since they
- are unlikely to be useful and can cause problems with shared
- stack slots. */
- if (reload_completed)
- flags &= ~(PROP_REG_INFO | PROP_AUTOINC);
-
- /* We want alias analysis information for local dead store elimination. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- init_alias_analysis ();
-
- /* Always remove no-op moves. Do this before other processing so
- that we don't have to keep re-scanning them. */
- delete_noop_moves (f);
- purge_all_dead_edges (false);
-
- /* Some targets can emit simpler epilogues if they know that sp was
- not ever modified during the function. After reload, of course,
- we've already emitted the epilogue so there's no sense searching. */
- if (! reload_completed)
- notice_stack_pointer_modification (f);
-
- /* Allocate and zero out data structures that will record the
- data from lifetime analysis. */
- allocate_reg_life_data ();
- allocate_bb_life_data ();
-
- /* Find the set of registers live on function exit. */
- mark_regs_live_at_end (EXIT_BLOCK_PTR->global_live_at_start);
-
- /* "Update" life info from zero. It'd be nice to begin the
- relaxation with just the exit and noreturn blocks, but that set
- is not immediately handy. */
-
- if (flags & PROP_REG_INFO)
- memset (regs_ever_live, 0, sizeof (regs_ever_live));
- update_life_info (NULL, UPDATE_LIFE_GLOBAL, flags);
-
- /* Clean up. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- end_alias_analysis ();
-
- if (file)
- dump_flow_info (file);
-
- free_basic_block_vars (1);
-
-#ifdef ENABLE_CHECKING
- {
- rtx insn;
-
- /* Search for any REG_LABEL notes which reference deleted labels. */
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- {
- rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
-
- if (inote && GET_CODE (inote) == NOTE_INSN_DELETED_LABEL)
- abort ();
- }
- }
-#endif
-
- rebuild_jump_labels (get_insns ());
-
- /* Removing dead insns should've made jumptables really dead. */
- delete_dead_jumptables ();
-}
-
-/* A subroutine of verify_wide_reg, called through for_each_rtx.
- Search for REGNO. If found, return 2 if it is not wider than
- word_mode. */
-
-static int
-verify_wide_reg_1 (px, pregno)
- rtx *px;
- void *pregno;
-{
- rtx x = *px;
- unsigned int regno = *(int *) pregno;
-
- if (GET_CODE (x) == REG && REGNO (x) == regno)
- {
- if (GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD)
- return 2;
- return 1;
- }
- return 0;
-}
-
-/* A subroutine of verify_local_live_at_start. Search through insns
- of BB looking for register REGNO. */
-
-static void
-verify_wide_reg (regno, bb)
- int regno;
- basic_block bb;
-{
- rtx head = bb->head, end = bb->end;
-
- while (1)
- {
- if (INSN_P (head))
- {
- int r = for_each_rtx (&PATTERN (head), verify_wide_reg_1, ®no);
- if (r == 1)
- return;
- if (r == 2)
- break;
- }
- if (head == end)
- break;
- head = NEXT_INSN (head);
- }
-
- if (rtl_dump_file)
- {
- fprintf (rtl_dump_file, "Register %d died unexpectedly.\n", regno);
- dump_bb (bb, rtl_dump_file);
- }
- abort ();
-}
-
-/* A subroutine of update_life_info. Verify that there are no untoward
- changes in live_at_start during a local update. */
-
-static void
-verify_local_live_at_start (new_live_at_start, bb)
- regset new_live_at_start;
- basic_block bb;
-{
- if (reload_completed)
- {
- /* After reload, there are no pseudos, nor subregs of multi-word
- registers. The regsets should exactly match. */
- if (! REG_SET_EQUAL_P (new_live_at_start, bb->global_live_at_start))
- {
- if (rtl_dump_file)
- {
- fprintf (rtl_dump_file,
- "live_at_start mismatch in bb %d, aborting\nNew:\n",
- bb->index);
- debug_bitmap_file (rtl_dump_file, new_live_at_start);
- fputs ("Old:\n", rtl_dump_file);
- dump_bb (bb, rtl_dump_file);
- }
- abort ();
- }
- }
- else
- {
- int i;
-
- /* Find the set of changed registers. */
- XOR_REG_SET (new_live_at_start, bb->global_live_at_start);
-
- EXECUTE_IF_SET_IN_REG_SET (new_live_at_start, 0, i,
- {
- /* No registers should die. */
- if (REGNO_REG_SET_P (bb->global_live_at_start, i))
- {
- if (rtl_dump_file)
- {
- fprintf (rtl_dump_file,
- "Register %d died unexpectedly.\n", i);
- dump_bb (bb, rtl_dump_file);
- }
- abort ();
- }
-
- /* Verify that the now-live register is wider than word_mode. */
- verify_wide_reg (i, bb);
- });
- }
-}
-
-/* Updates life information starting with the basic blocks set in BLOCKS.
- If BLOCKS is null, consider it to be the universal set.
-
- If EXTENT is UPDATE_LIFE_LOCAL, such as after splitting or peepholeing,
- we are only expecting local modifications to basic blocks. If we find
- extra registers live at the beginning of a block, then we either killed
- useful data, or we have a broken split that wants data not provided.
- If we find registers removed from live_at_start, that means we have
- a broken peephole that is killing a register it shouldn't.
-
- ??? This is not true in one situation -- when a pre-reload splitter
- generates subregs of a multi-word pseudo, current life analysis will
- lose the kill. So we _can_ have a pseudo go live. How irritating.
-
- Including PROP_REG_INFO does not properly refresh regs_ever_live
- unless the caller resets it to zero. */
-
-void
-update_life_info (blocks, extent, prop_flags)
- sbitmap blocks;
- enum update_life_extent extent;
- int prop_flags;
-{
- regset tmp;
- regset_head tmp_head;
- int i;
- int stabilized_prop_flags = prop_flags;
-
- tmp = INITIALIZE_REG_SET (tmp_head);
-
- timevar_push ((extent == UPDATE_LIFE_LOCAL || blocks)
- ? TV_LIFE_UPDATE : TV_LIFE);
-
- /* Changes to the CFG are only allowed when
- doing a global update for the entire CFG. */
- if ((prop_flags & PROP_ALLOW_CFG_CHANGES)
- && (extent == UPDATE_LIFE_LOCAL || blocks))
- abort ();
-
- /* Clear log links in case we are asked to (re)compute them. */
- if (prop_flags & PROP_LOG_LINKS)
- clear_log_links (blocks);
-
- /* For a global update, we go through the relaxation process again. */
- if (extent != UPDATE_LIFE_LOCAL)
- {
- for ( ; ; )
- {
- int changed = 0;
-
- calculate_global_regs_live (blocks, blocks,
- prop_flags & (PROP_SCAN_DEAD_CODE
- | PROP_ALLOW_CFG_CHANGES));
-
- if ((prop_flags & (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
- != (PROP_KILL_DEAD_CODE | PROP_ALLOW_CFG_CHANGES))
- break;
-
- /* Removing dead code may allow the CFG to be simplified which
- in turn may allow for further dead code detection / removal. */
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb = BASIC_BLOCK (i);
-
- COPY_REG_SET (tmp, bb->global_live_at_end);
- changed |= propagate_block (bb, tmp, NULL, NULL,
- prop_flags & (PROP_SCAN_DEAD_CODE
- | PROP_KILL_DEAD_CODE));
- }
-
- /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to
- subsequent propagate_block calls, since removing or acting as
- removing dead code can affect global register liveness, which
- is supposed to be finalized for this call after this loop. */
- stabilized_prop_flags
- &= ~(PROP_SCAN_DEAD_CODE | PROP_KILL_DEAD_CODE);
-
- if (! changed)
- break;
-
- /* We repeat regardless of what cleanup_cfg says. If there were
- instructions deleted above, that might have been only a
- partial improvement (see MAX_MEM_SET_LIST_LEN usage).
- Further improvement may be possible. */
- cleanup_cfg (CLEANUP_EXPENSIVE);
- }
-
- /* If asked, remove notes from the blocks we'll update. */
- if (extent == UPDATE_LIFE_GLOBAL_RM_NOTES)
- count_or_remove_death_notes (blocks, 1);
- }
-
- if (blocks)
- {
- EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
-
- COPY_REG_SET (tmp, bb->global_live_at_end);
- propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
-
- if (extent == UPDATE_LIFE_LOCAL)
- verify_local_live_at_start (tmp, bb);
- });
- }
- else
- {
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb = BASIC_BLOCK (i);
-
- COPY_REG_SET (tmp, bb->global_live_at_end);
-
- propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags);
-
- if (extent == UPDATE_LIFE_LOCAL)
- verify_local_live_at_start (tmp, bb);
- }
- }
-
- FREE_REG_SET (tmp);
-
- if (prop_flags & PROP_REG_INFO)
- {
- /* The only pseudos that are live at the beginning of the function
- are those that were not set anywhere in the function. local-alloc
- doesn't know how to handle these correctly, so mark them as not
- local to any one basic block. */
- EXECUTE_IF_SET_IN_REG_SET (ENTRY_BLOCK_PTR->global_live_at_end,
- FIRST_PSEUDO_REGISTER, i,
- { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
-
- /* We have a problem with any pseudoreg that lives across the setjmp.
- ANSI says that if a user variable does not change in value between
- the setjmp and the longjmp, then the longjmp preserves it. This
- includes longjmp from a place where the pseudo appears dead.
- (In principle, the value still exists if it is in scope.)
- If the pseudo goes in a hard reg, some other value may occupy
- that hard reg where this pseudo is dead, thus clobbering the pseudo.
- Conclusion: such a pseudo must not go in a hard reg. */
- EXECUTE_IF_SET_IN_REG_SET (regs_live_at_setjmp,
- FIRST_PSEUDO_REGISTER, i,
- {
- if (regno_reg_rtx[i] != 0)
- {
- REG_LIVE_LENGTH (i) = -1;
- REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
- }
- });
- }
- timevar_pop ((extent == UPDATE_LIFE_LOCAL || blocks)
- ? TV_LIFE_UPDATE : TV_LIFE);
-}
-
-/* Free the variables allocated by find_basic_blocks.
-
- KEEP_HEAD_END_P is non-zero if basic_block_info is not to be freed. */
-
-void
-free_basic_block_vars (keep_head_end_p)
- int keep_head_end_p;
-{
- if (! keep_head_end_p)
- {
- if (basic_block_info)
- {
- clear_edges ();
- VARRAY_FREE (basic_block_info);
- }
- n_basic_blocks = 0;
-
- ENTRY_BLOCK_PTR->aux = NULL;
- ENTRY_BLOCK_PTR->global_live_at_end = NULL;
- EXIT_BLOCK_PTR->aux = NULL;
- EXIT_BLOCK_PTR->global_live_at_start = NULL;
- }
-}
-
-/* Delete any insns that copy a register to itself. */
-
-void
-delete_noop_moves (f)
- rtx f ATTRIBUTE_UNUSED;
-{
- int i;
- rtx insn, next;
- basic_block bb;
-
- for (i = 0; i < n_basic_blocks; i++)
- {
- bb = BASIC_BLOCK (i);
- for (insn = bb->head; insn != NEXT_INSN (bb->end); insn = next)
- {
- next = NEXT_INSN (insn);
- if (INSN_P (insn) && noop_move_p (insn))
- {
- rtx note;
-
- /* If we're about to remove the first insn of a libcall
- then move the libcall note to the next real insn and
- update the retval note. */
- if ((note = find_reg_note (insn, REG_LIBCALL, NULL_RTX))
- && XEXP (note, 0) != insn)
- {
- rtx new_libcall_insn = next_real_insn (insn);
- rtx retval_note = find_reg_note (XEXP (note, 0),
- REG_RETVAL, NULL_RTX);
- REG_NOTES (new_libcall_insn)
- = gen_rtx_INSN_LIST (REG_LIBCALL, XEXP (note, 0),
- REG_NOTES (new_libcall_insn));
- XEXP (retval_note, 0) = new_libcall_insn;
- }
-
- /* Do not call delete_insn here since that may change
- the basic block boundaries which upsets some callers. */
- PUT_CODE (insn, NOTE);
- NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (insn) = 0;
- }
- }
- }
-}
-
-/* Delete any jump tables never referenced. We can't delete them at the
- time of removing tablejump insn as they are referenced by the preceding
- insns computing the destination, so we delay deleting and garbagecollect
- them once life information is computed. */
-static void
-delete_dead_jumptables ()
-{
- rtx insn, next;
- for (insn = get_insns (); insn; insn = next)
- {
- next = NEXT_INSN (insn);
- if (GET_CODE (insn) == CODE_LABEL
- && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
- && GET_CODE (next) == JUMP_INSN
- && (GET_CODE (PATTERN (next)) == ADDR_VEC
- || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
- {
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Dead jumptable %i removed\n", INSN_UID (insn));
- delete_insn (NEXT_INSN (insn));
- delete_insn (insn);
- next = NEXT_INSN (next);
- }
- }
-}
-
-/* Determine if the stack pointer is constant over the life of the function.
- Only useful before prologues have been emitted. */
-
-static void
-notice_stack_pointer_modification_1 (x, pat, data)
- rtx x;
- rtx pat ATTRIBUTE_UNUSED;
- void *data ATTRIBUTE_UNUSED;
-{
- if (x == stack_pointer_rtx
- /* The stack pointer is only modified indirectly as the result
- of a push until later in flow. See the comments in rtl.texi
- regarding Embedded Side-Effects on Addresses. */
- || (GET_CODE (x) == MEM
- && GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == 'a'
- && XEXP (XEXP (x, 0), 0) == stack_pointer_rtx))
- current_function_sp_is_unchanging = 0;
-}
-
-static void
-notice_stack_pointer_modification (f)
- rtx f;
-{
- rtx insn;
-
- /* Assume that the stack pointer is unchanging if alloca hasn't
- been used. */
- current_function_sp_is_unchanging = !current_function_calls_alloca;
- if (! current_function_sp_is_unchanging)
- return;
-
- for (insn = f; insn; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- {
- /* Check if insn modifies the stack pointer. */
- note_stores (PATTERN (insn), notice_stack_pointer_modification_1,
- NULL);
- if (! current_function_sp_is_unchanging)
- return;
- }
- }
-}
-
-/* Mark a register in SET. Hard registers in large modes get all
- of their component registers set as well. */
-
-static void
-mark_reg (reg, xset)
- rtx reg;
- void *xset;
-{
- regset set = (regset) xset;
- int regno = REGNO (reg);
-
- if (GET_MODE (reg) == BLKmode)
- abort ();
-
- SET_REGNO_REG_SET (set, regno);
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (reg));
- while (--n > 0)
- SET_REGNO_REG_SET (set, regno + n);
- }
-}
-
-/* Mark those regs which are needed at the end of the function as live
- at the end of the last basic block. */
-
-static void
-mark_regs_live_at_end (set)
- regset set;
-{
- unsigned int i;
-
- /* If exiting needs the right stack value, consider the stack pointer
- live at the end of the function. */
- if ((HAVE_epilogue && reload_completed)
- || ! EXIT_IGNORE_STACK
- || (! FRAME_POINTER_REQUIRED
- && ! current_function_calls_alloca
- && flag_omit_frame_pointer)
- || current_function_sp_is_unchanging)
- {
- SET_REGNO_REG_SET (set, STACK_POINTER_REGNUM);
- }
-
- /* Mark the frame pointer if needed at the end of the function. If
- we end up eliminating it, it will be removed from the live list
- of each basic block by reload. */
-
- if (! reload_completed || frame_pointer_needed)
- {
- SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM);
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- /* If they are different, also mark the hard frame pointer as live. */
- if (! LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
- SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM);
-#endif
- }
-
-#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
- /* Many architectures have a GP register even without flag_pic.
- Assume the pic register is not in use, or will be handled by
- other means, if it is not fixed. */
- if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
- && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
- SET_REGNO_REG_SET (set, PIC_OFFSET_TABLE_REGNUM);
-#endif
-
- /* Mark all global registers, and all registers used by the epilogue
- as being live at the end of the function since they may be
- referenced by our caller. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i] || EPILOGUE_USES (i))
- SET_REGNO_REG_SET (set, i);
-
- if (HAVE_epilogue && reload_completed)
- {
- /* Mark all call-saved registers that we actually used. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (regs_ever_live[i] && ! LOCAL_REGNO (i)
- && ! TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
- SET_REGNO_REG_SET (set, i);
- }
-
-#ifdef EH_RETURN_DATA_REGNO
- /* Mark the registers that will contain data for the handler. */
- if (reload_completed && current_function_calls_eh_return)
- for (i = 0; ; ++i)
- {
- unsigned regno = EH_RETURN_DATA_REGNO(i);
- if (regno == INVALID_REGNUM)
- break;
- SET_REGNO_REG_SET (set, regno);
- }
-#endif
-#ifdef EH_RETURN_STACKADJ_RTX
- if ((! HAVE_epilogue || ! reload_completed)
- && current_function_calls_eh_return)
- {
- rtx tmp = EH_RETURN_STACKADJ_RTX;
- if (tmp && REG_P (tmp))
- mark_reg (tmp, set);
- }
-#endif
-#ifdef EH_RETURN_HANDLER_RTX
- if ((! HAVE_epilogue || ! reload_completed)
- && current_function_calls_eh_return)
- {
- rtx tmp = EH_RETURN_HANDLER_RTX;
- if (tmp && REG_P (tmp))
- mark_reg (tmp, set);
- }
-#endif
-
- /* Mark function return value. */
- diddle_return_value (mark_reg, set);
-}
-
-/* Callback function for for_each_successor_phi. DATA is a regset.
- Sets the SRC_REGNO, the regno of the phi alternative for phi node
- INSN, in the regset. */
-
-static int
-set_phi_alternative_reg (insn, dest_regno, src_regno, data)
- rtx insn ATTRIBUTE_UNUSED;
- int dest_regno ATTRIBUTE_UNUSED;
- int src_regno;
- void *data;
-{
- regset live = (regset) data;
- SET_REGNO_REG_SET (live, src_regno);
- return 0;
-}
-
-/* Propagate global life info around the graph of basic blocks. Begin
- considering blocks with their corresponding bit set in BLOCKS_IN.
- If BLOCKS_IN is null, consider it the universal set.
-
- BLOCKS_OUT is set for every block that was changed. */
-
-static void
-calculate_global_regs_live (blocks_in, blocks_out, flags)
- sbitmap blocks_in, blocks_out;
- int flags;
-{
- basic_block *queue, *qhead, *qtail, *qend;
- regset tmp, new_live_at_end, call_used;
- regset_head tmp_head, call_used_head;
- regset_head new_live_at_end_head;
- int i;
-
- tmp = INITIALIZE_REG_SET (tmp_head);
- new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
- call_used = INITIALIZE_REG_SET (call_used_head);
-
- /* Inconveniently, this is only readily available in hard reg set form. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
- if (call_used_regs[i])
- SET_REGNO_REG_SET (call_used, i);
-
- /* Create a worklist. Allocate an extra slot for ENTRY_BLOCK, and one
- because the `head == tail' style test for an empty queue doesn't
- work with a full queue. */
- queue = (basic_block *) xmalloc ((n_basic_blocks + 2) * sizeof (*queue));
- qtail = queue;
- qhead = qend = queue + n_basic_blocks + 2;
-
- /* Queue the blocks set in the initial mask. Do this in reverse block
- number order so that we are more likely for the first round to do
- useful work. We use AUX non-null to flag that the block is queued. */
- if (blocks_in)
- {
- /* Clear out the garbage that might be hanging out in bb->aux. */
- for (i = n_basic_blocks - 1; i >= 0; --i)
- BASIC_BLOCK (i)->aux = NULL;
-
- EXECUTE_IF_SET_IN_SBITMAP (blocks_in, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
- *--qhead = bb;
- bb->aux = bb;
- });
- }
- else
- {
- for (i = 0; i < n_basic_blocks; ++i)
- {
- basic_block bb = BASIC_BLOCK (i);
- *--qhead = bb;
- bb->aux = bb;
- }
- }
-
- /* We clean aux when we remove the initially-enqueued bbs, but we
- don't enqueue ENTRY and EXIT initially, so clean them upfront and
- unconditionally. */
- ENTRY_BLOCK_PTR->aux = EXIT_BLOCK_PTR->aux = NULL;
-
- if (blocks_out)
- sbitmap_zero (blocks_out);
-
- /* We work through the queue until there are no more blocks. What
- is live at the end of this block is precisely the union of what
- is live at the beginning of all its successors. So, we set its
- GLOBAL_LIVE_AT_END field based on the GLOBAL_LIVE_AT_START field
- for its successors. Then, we compute GLOBAL_LIVE_AT_START for
- this block by walking through the instructions in this block in
- reverse order and updating as we go. If that changed
- GLOBAL_LIVE_AT_START, we add the predecessors of the block to the
- queue; they will now need to recalculate GLOBAL_LIVE_AT_END.
-
- We are guaranteed to terminate, because GLOBAL_LIVE_AT_START
- never shrinks. If a register appears in GLOBAL_LIVE_AT_START, it
- must either be live at the end of the block, or used within the
- block. In the latter case, it will certainly never disappear
- from GLOBAL_LIVE_AT_START. In the former case, the register
- could go away only if it disappeared from GLOBAL_LIVE_AT_START
- for one of the successor blocks. By induction, that cannot
- occur. */
- while (qhead != qtail)
- {
- int rescan, changed;
- basic_block bb;
- edge e;
-
- bb = *qhead++;
- if (qhead == qend)
- qhead = queue;
- bb->aux = NULL;
-
- /* Begin by propagating live_at_start from the successor blocks. */
- CLEAR_REG_SET (new_live_at_end);
-
- if (bb->succ)
- for (e = bb->succ; e; e = e->succ_next)
- {
- basic_block sb = e->dest;
-
- /* Call-clobbered registers die across exception and
- call edges. */
- /* ??? Abnormal call edges ignored for the moment, as this gets
- confused by sibling call edges, which crashes reg-stack. */
- if (e->flags & EDGE_EH)
- {
- bitmap_operation (tmp, sb->global_live_at_start,
- call_used, BITMAP_AND_COMPL);
- IOR_REG_SET (new_live_at_end, tmp);
- }
- else
- IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
-
- /* If a target saves one register in another (instead of on
- the stack) the save register will need to be live for EH. */
- if (e->flags & EDGE_EH)
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (EH_USES (i))
- SET_REGNO_REG_SET (new_live_at_end, i);
- }
- else
- {
- /* This might be a noreturn function that throws. And
- even if it isn't, getting the unwind info right helps
- debugging. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (EH_USES (i))
- SET_REGNO_REG_SET (new_live_at_end, i);
- }
-
- /* The all-important stack pointer must always be live. */
- SET_REGNO_REG_SET (new_live_at_end, STACK_POINTER_REGNUM);
-
- /* Before reload, there are a few registers that must be forced
- live everywhere -- which might not already be the case for
- blocks within infinite loops. */
- if (! reload_completed)
- {
- /* Any reference to any pseudo before reload is a potential
- reference of the frame pointer. */
- SET_REGNO_REG_SET (new_live_at_end, FRAME_POINTER_REGNUM);
-
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- /* Pseudos with argument area equivalences may require
- reloading via the argument pointer. */
- if (fixed_regs[ARG_POINTER_REGNUM])
- SET_REGNO_REG_SET (new_live_at_end, ARG_POINTER_REGNUM);
-#endif
-
- /* Any constant, or pseudo with constant equivalences, may
- require reloading from memory using the pic register. */
- if (PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
- && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
- SET_REGNO_REG_SET (new_live_at_end, PIC_OFFSET_TABLE_REGNUM);
- }
-
- /* Regs used in phi nodes are not included in
- global_live_at_start, since they are live only along a
- particular edge. Set those regs that are live because of a
- phi node alternative corresponding to this particular block. */
- if (in_ssa_form)
- for_each_successor_phi (bb, &set_phi_alternative_reg,
- new_live_at_end);
-
- if (bb == ENTRY_BLOCK_PTR)
- {
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
- continue;
- }
-
- /* On our first pass through this block, we'll go ahead and continue.
- Recognize first pass by local_set NULL. On subsequent passes, we
- get to skip out early if live_at_end wouldn't have changed. */
-
- if (bb->local_set == NULL)
- {
- bb->local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- bb->cond_local_set = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- rescan = 1;
- }
- else
- {
- /* If any bits were removed from live_at_end, we'll have to
- rescan the block. This wouldn't be necessary if we had
- precalculated local_live, however with PROP_SCAN_DEAD_CODE
- local_live is really dependent on live_at_end. */
- CLEAR_REG_SET (tmp);
- rescan = bitmap_operation (tmp, bb->global_live_at_end,
- new_live_at_end, BITMAP_AND_COMPL);
-
- if (! rescan)
- {
- /* If any of the registers in the new live_at_end set are
- conditionally set in this basic block, we must rescan.
- This is because conditional lifetimes at the end of the
- block do not just take the live_at_end set into account,
- but also the liveness at the start of each successor
- block. We can miss changes in those sets if we only
- compare the new live_at_end against the previous one. */
- CLEAR_REG_SET (tmp);
- rescan = bitmap_operation (tmp, new_live_at_end,
- bb->cond_local_set, BITMAP_AND);
- }
-
- if (! rescan)
- {
- /* Find the set of changed bits. Take this opportunity
- to notice that this set is empty and early out. */
- CLEAR_REG_SET (tmp);
- changed = bitmap_operation (tmp, bb->global_live_at_end,
- new_live_at_end, BITMAP_XOR);
- if (! changed)
- continue;
-
- /* If any of the changed bits overlap with local_set,
- we'll have to rescan the block. Detect overlap by
- the AND with ~local_set turning off bits. */
- rescan = bitmap_operation (tmp, tmp, bb->local_set,
- BITMAP_AND_COMPL);
- }
- }
-
- /* Let our caller know that BB changed enough to require its
- death notes updated. */
- if (blocks_out)
- SET_BIT (blocks_out, bb->index);
-
- if (! rescan)
- {
- /* Add to live_at_start the set of all registers in
- new_live_at_end that aren't in the old live_at_end. */
-
- bitmap_operation (tmp, new_live_at_end, bb->global_live_at_end,
- BITMAP_AND_COMPL);
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
-
- changed = bitmap_operation (bb->global_live_at_start,
- bb->global_live_at_start,
- tmp, BITMAP_IOR);
- if (! changed)
- continue;
- }
- else
- {
- COPY_REG_SET (bb->global_live_at_end, new_live_at_end);
-
- /* Rescan the block insn by insn to turn (a copy of) live_at_end
- into live_at_start. */
- propagate_block (bb, new_live_at_end, bb->local_set,
- bb->cond_local_set, flags);
-
- /* If live_at start didn't change, no need to go farther. */
- if (REG_SET_EQUAL_P (bb->global_live_at_start, new_live_at_end))
- continue;
-
- COPY_REG_SET (bb->global_live_at_start, new_live_at_end);
- }
-
- /* Queue all predecessors of BB so that we may re-examine
- their live_at_end. */
- for (e = bb->pred; e; e = e->pred_next)
- {
- basic_block pb = e->src;
- if (pb->aux == NULL)
- {
- *qtail++ = pb;
- if (qtail == qend)
- qtail = queue;
- pb->aux = pb;
- }
- }
- }
-
- FREE_REG_SET (tmp);
- FREE_REG_SET (new_live_at_end);
- FREE_REG_SET (call_used);
-
- if (blocks_out)
- {
- EXECUTE_IF_SET_IN_SBITMAP (blocks_out, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
- FREE_REG_SET (bb->local_set);
- FREE_REG_SET (bb->cond_local_set);
- });
- }
- else
- {
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb = BASIC_BLOCK (i);
- FREE_REG_SET (bb->local_set);
- FREE_REG_SET (bb->cond_local_set);
- }
- }
-
- free (queue);
-}
-
-\f
-/* This structure is used to pass parameters to an from the
- the function find_regno_partial(). It is used to pass in the
- register number we are looking, as well as to return any rtx
- we find. */
-
-typedef struct {
- unsigned regno_to_find;
- rtx retval;
-} find_regno_partial_param;
-
-
-/* Find the rtx for the reg numbers specified in 'data' if it is
- part of an expression which only uses part of the register. Return
- it in the structure passed in. */
-static int
-find_regno_partial (ptr, data)
- rtx *ptr;
- void *data;
-{
- find_regno_partial_param *param = (find_regno_partial_param *)data;
- unsigned reg = param->regno_to_find;
- param->retval = NULL_RTX;
-
- if (*ptr == NULL_RTX)
- return 0;
-
- switch (GET_CODE (*ptr))
- {
- case ZERO_EXTRACT:
- case SIGN_EXTRACT:
- case STRICT_LOW_PART:
- if (GET_CODE (XEXP (*ptr, 0)) == REG && REGNO (XEXP (*ptr, 0)) == reg)
- {
- param->retval = XEXP (*ptr, 0);
- return 1;
- }
- break;
-
- case SUBREG:
- if (GET_CODE (SUBREG_REG (*ptr)) == REG
- && REGNO (SUBREG_REG (*ptr)) == reg)
- {
- param->retval = SUBREG_REG (*ptr);
- return 1;
- }
- break;
-
- default:
- break;
- }
-
- return 0;
-}
-
-/* Process all immediate successors of the entry block looking for pseudo
- registers which are live on entry. Find all of those whose first
- instance is a partial register reference of some kind, and initialize
- them to 0 after the entry block. This will prevent bit sets within
- registers whose value is unknown, and may contain some kind of sticky
- bits we don't want. */
-
-int
-initialize_uninitialized_subregs ()
-{
- rtx insn;
- edge e;
- int reg, did_something = 0;
- find_regno_partial_param param;
-
- for (e = ENTRY_BLOCK_PTR->succ; e; e = e->succ_next)
- {
- basic_block bb = e->dest;
- regset map = bb->global_live_at_start;
- EXECUTE_IF_SET_IN_REG_SET (map,
- FIRST_PSEUDO_REGISTER, reg,
- {
- int uid = REGNO_FIRST_UID (reg);
- rtx i;
-
- /* Find an insn which mentions the register we are looking for.
- Its preferable to have an instance of the register's rtl since
- there may be various flags set which we need to duplicate.
- If we can't find it, its probably an automatic whose initial
- value doesn't matter, or hopefully something we don't care about. */
- for (i = get_insns (); i && INSN_UID (i) != uid; i = NEXT_INSN (i))
- ;
- if (i != NULL_RTX)
- {
- /* Found the insn, now get the REG rtx, if we can. */
- param.regno_to_find = reg;
- for_each_rtx (&i, find_regno_partial, ¶m);
- if (param.retval != NULL_RTX)
- {
- insn = gen_move_insn (param.retval,
- CONST0_RTX (GET_MODE (param.retval)));
- insert_insn_on_edge (insn, e);
- did_something = 1;
- }
- }
- });
- }
-
- if (did_something)
- commit_edge_insertions ();
- return did_something;
-}
-
-\f
-/* Subroutines of life analysis. */
-
-/* Allocate the permanent data structures that represent the results
- of life analysis. Not static since used also for stupid life analysis. */
-
-void
-allocate_bb_life_data ()
-{
- int i;
-
- for (i = 0; i < n_basic_blocks; i++)
- {
- basic_block bb = BASIC_BLOCK (i);
-
- bb->global_live_at_start = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- bb->global_live_at_end = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- }
-
- ENTRY_BLOCK_PTR->global_live_at_end
- = OBSTACK_ALLOC_REG_SET (&flow_obstack);
- EXIT_BLOCK_PTR->global_live_at_start
- = OBSTACK_ALLOC_REG_SET (&flow_obstack);
-
- regs_live_at_setjmp = OBSTACK_ALLOC_REG_SET (&flow_obstack);
-}
-
-void
-allocate_reg_life_data ()
-{
- int i;
-
- max_regno = max_reg_num ();
-
- /* Recalculate the register space, in case it has grown. Old style
- vector oriented regsets would set regset_{size,bytes} here also. */
- allocate_reg_info (max_regno, FALSE, FALSE);
-
- /* Reset all the data we'll collect in propagate_block and its
- subroutines. */
- for (i = 0; i < max_regno; i++)
- {
- REG_N_SETS (i) = 0;
- REG_N_REFS (i) = 0;
- REG_N_DEATHS (i) = 0;
- REG_N_CALLS_CROSSED (i) = 0;
- REG_LIVE_LENGTH (i) = 0;
- REG_BASIC_BLOCK (i) = REG_BLOCK_UNKNOWN;
- }
-}
-
-/* Delete dead instructions for propagate_block. */
-
-static void
-propagate_block_delete_insn (bb, insn)
- basic_block bb;
- rtx insn;
-{
- rtx inote = find_reg_note (insn, REG_LABEL, NULL_RTX);
- bool purge = false;
-
- /* If the insn referred to a label, and that label was attached to
- an ADDR_VEC, it's safe to delete the ADDR_VEC. In fact, it's
- pretty much mandatory to delete it, because the ADDR_VEC may be
- referencing labels that no longer exist.
-
- INSN may reference a deleted label, particularly when a jump
- table has been optimized into a direct jump. There's no
- real good way to fix up the reference to the deleted label
- when the label is deleted, so we just allow it here.
-
- After dead code elimination is complete, we do search for
- any REG_LABEL notes which reference deleted labels as a
- sanity check. */
-
- if (inote && GET_CODE (inote) == CODE_LABEL)
- {
- rtx label = XEXP (inote, 0);
- rtx next;
-
- /* The label may be forced if it has been put in the constant
- pool. If that is the only use we must discard the table
- jump following it, but not the label itself. */
- if (LABEL_NUSES (label) == 1 + LABEL_PRESERVE_P (label)
- && (next = next_nonnote_insn (label)) != NULL
- && GET_CODE (next) == JUMP_INSN
- && (GET_CODE (PATTERN (next)) == ADDR_VEC
- || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
- {
- rtx pat = PATTERN (next);
- int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
- int len = XVECLEN (pat, diff_vec_p);
- int i;
-
- for (i = 0; i < len; i++)
- LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--;
-
- delete_insn (next);
- }
- }
-
- if (bb->end == insn)
- purge = true;
- delete_insn (insn);
- if (purge)
- purge_dead_edges (bb);
-}
-
-/* Delete dead libcalls for propagate_block. Return the insn
- before the libcall. */
-
-static rtx
-propagate_block_delete_libcall ( insn, note)
- rtx insn, note;
-{
- rtx first = XEXP (note, 0);
- rtx before = PREV_INSN (first);
-
- delete_insn_chain (first, insn);
- return before;
-}
-
-/* Update the life-status of regs for one insn. Return the previous insn. */
-
-rtx
-propagate_one_insn (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- rtx prev = PREV_INSN (insn);
- int flags = pbi->flags;
- int insn_is_dead = 0;
- int libcall_is_dead = 0;
- rtx note;
- int i;
-
- if (! INSN_P (insn))
- return prev;
-
- note = find_reg_note (insn, REG_RETVAL, NULL_RTX);
- if (flags & PROP_SCAN_DEAD_CODE)
- {
- insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn));
- libcall_is_dead = (insn_is_dead && note != 0
- && libcall_dead_p (pbi, note, insn));
- }
-
- /* If an instruction consists of just dead store(s) on final pass,
- delete it. */
- if ((flags & PROP_KILL_DEAD_CODE) && insn_is_dead)
- {
- /* If we're trying to delete a prologue or epilogue instruction
- that isn't flagged as possibly being dead, something is wrong.
- But if we are keeping the stack pointer depressed, we might well
- be deleting insns that are used to compute the amount to update
- it by, so they are fine. */
- if (reload_completed
- && !(TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
- && (TYPE_RETURNS_STACK_DEPRESSED
- (TREE_TYPE (current_function_decl))))
- && (((HAVE_epilogue || HAVE_prologue)
- && prologue_epilogue_contains (insn))
- || (HAVE_sibcall_epilogue
- && sibcall_epilogue_contains (insn)))
- && find_reg_note (insn, REG_MAYBE_DEAD, NULL_RTX) == 0)
- fatal_insn ("Attempt to delete prologue/epilogue insn:", insn);
-
- /* Record sets. Do this even for dead instructions, since they
- would have killed the values if they hadn't been deleted. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- /* CC0 is now known to be dead. Either this insn used it,
- in which case it doesn't anymore, or clobbered it,
- so the next insn can't use it. */
- pbi->cc0_live = 0;
-
- if (libcall_is_dead)
- prev = propagate_block_delete_libcall ( insn, note);
- else
- {
-
- /* If INSN contains a RETVAL note and is dead, but the libcall
- as a whole is not dead, then we want to remove INSN, but
- not the whole libcall sequence.
-
- However, we need to also remove the dangling REG_LIBCALL
- note so that we do not have mis-matched LIBCALL/RETVAL
- notes. In theory we could find a new location for the
- REG_RETVAL note, but it hardly seems worth the effort.
-
- NOTE at this point will be the RETVAL note if it exists. */
- if (note)
- {
- rtx libcall_note;
-
- libcall_note
- = find_reg_note (XEXP (note, 0), REG_LIBCALL, NULL_RTX);
- remove_note (XEXP (note, 0), libcall_note);
- }
-
- /* Similarly if INSN contains a LIBCALL note, remove the
- dangling REG_RETVAL note. */
- note = find_reg_note (insn, REG_LIBCALL, NULL_RTX);
- if (note)
- {
- rtx retval_note;
-
- retval_note
- = find_reg_note (XEXP (note, 0), REG_RETVAL, NULL_RTX);
- remove_note (XEXP (note, 0), retval_note);
- }
-
- /* Now delete INSN. */
- propagate_block_delete_insn (pbi->bb, insn);
- }
-
- return prev;
- }
-
- /* See if this is an increment or decrement that can be merged into
- a following memory address. */
-#ifdef AUTO_INC_DEC
- {
- rtx x = single_set (insn);
-
- /* Does this instruction increment or decrement a register? */
- if ((flags & PROP_AUTOINC)
- && x != 0
- && GET_CODE (SET_DEST (x)) == REG
- && (GET_CODE (SET_SRC (x)) == PLUS
- || GET_CODE (SET_SRC (x)) == MINUS)
- && XEXP (SET_SRC (x), 0) == SET_DEST (x)
- && GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
- /* Ok, look for a following memory ref we can combine with.
- If one is found, change the memory ref to a PRE_INC
- or PRE_DEC, cancel this insn, and return 1.
- Return 0 if nothing has been done. */
- && try_pre_increment_1 (pbi, insn))
- return prev;
- }
-#endif /* AUTO_INC_DEC */
-
- CLEAR_REG_SET (pbi->new_set);
-
- /* If this is not the final pass, and this insn is copying the value of
- a library call and it's dead, don't scan the insns that perform the
- library call, so that the call's arguments are not marked live. */
- if (libcall_is_dead)
- {
- /* Record the death of the dest reg. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- insn = XEXP (note, 0);
- return PREV_INSN (insn);
- }
- else if (GET_CODE (PATTERN (insn)) == SET
- && SET_DEST (PATTERN (insn)) == stack_pointer_rtx
- && GET_CODE (SET_SRC (PATTERN (insn))) == PLUS
- && XEXP (SET_SRC (PATTERN (insn)), 0) == stack_pointer_rtx
- && GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == CONST_INT)
- /* We have an insn to pop a constant amount off the stack.
- (Such insns use PLUS regardless of the direction of the stack,
- and any insn to adjust the stack by a constant is always a pop.)
- These insns, if not dead stores, have no effect on life. */
- ;
- else
- {
- rtx note;
- /* Any regs live at the time of a call instruction must not go
- in a register clobbered by calls. Find all regs now live and
- record this for them. */
-
- if (GET_CODE (insn) == CALL_INSN && (flags & PROP_REG_INFO))
- EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
- { REG_N_CALLS_CROSSED (i)++; });
-
- /* Record sets. Do this even for dead instructions, since they
- would have killed the values if they hadn't been deleted. */
- mark_set_regs (pbi, PATTERN (insn), insn);
-
- if (GET_CODE (insn) == CALL_INSN)
- {
- int i;
- rtx note, cond;
-
- cond = NULL_RTX;
- if (GET_CODE (PATTERN (insn)) == COND_EXEC)
- cond = COND_EXEC_TEST (PATTERN (insn));
-
- /* Non-constant calls clobber memory. */
- if (! CONST_OR_PURE_CALL_P (insn))
- {
- free_EXPR_LIST_list (&pbi->mem_set_list);
- pbi->mem_set_list_len = 0;
- }
-
- /* There may be extra registers to be clobbered. */
- for (note = CALL_INSN_FUNCTION_USAGE (insn);
- note;
- note = XEXP (note, 1))
- if (GET_CODE (XEXP (note, 0)) == CLOBBER)
- mark_set_1 (pbi, CLOBBER, XEXP (XEXP (note, 0), 0),
- cond, insn, pbi->flags);
-
- /* Calls change all call-used and global registers. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
- {
- /* We do not want REG_UNUSED notes for these registers. */
- mark_set_1 (pbi, CLOBBER, gen_rtx_REG (reg_raw_mode[i], i),
- cond, insn,
- pbi->flags & ~(PROP_DEATH_NOTES | PROP_REG_INFO));
- }
- }
-
- /* If an insn doesn't use CC0, it becomes dead since we assume
- that every insn clobbers it. So show it dead here;
- mark_used_regs will set it live if it is referenced. */
- pbi->cc0_live = 0;
-
- /* Record uses. */
- if (! insn_is_dead)
- mark_used_regs (pbi, PATTERN (insn), NULL_RTX, insn);
- if ((flags & PROP_EQUAL_NOTES)
- && ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX))
- || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX))))
- mark_used_regs (pbi, XEXP (note, 0), NULL_RTX, insn);
-
- /* Sometimes we may have inserted something before INSN (such as a move)
- when we make an auto-inc. So ensure we will scan those insns. */
-#ifdef AUTO_INC_DEC
- prev = PREV_INSN (insn);
-#endif
-
- if (! insn_is_dead && GET_CODE (insn) == CALL_INSN)
- {
- int i;
- rtx note, cond;
-
- cond = NULL_RTX;
- if (GET_CODE (PATTERN (insn)) == COND_EXEC)
- cond = COND_EXEC_TEST (PATTERN (insn));
-
- /* Calls use their arguments. */
- for (note = CALL_INSN_FUNCTION_USAGE (insn);
- note;
- note = XEXP (note, 1))
- if (GET_CODE (XEXP (note, 0)) == USE)
- mark_used_regs (pbi, XEXP (XEXP (note, 0), 0),
- cond, insn);
-
- /* The stack ptr is used (honorarily) by a CALL insn. */
- SET_REGNO_REG_SET (pbi->reg_live, STACK_POINTER_REGNUM);
-
- /* Calls may also reference any of the global registers,
- so they are made live. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (global_regs[i])
- mark_used_reg (pbi, gen_rtx_REG (reg_raw_mode[i], i),
- cond, insn);
- }
- }
-
- /* On final pass, update counts of how many insns in which each reg
- is live. */
- if (flags & PROP_REG_INFO)
- EXECUTE_IF_SET_IN_REG_SET (pbi->reg_live, 0, i,
- { REG_LIVE_LENGTH (i)++; });
-
- return prev;
-}
-
-/* Initialize a propagate_block_info struct for public consumption.
- Note that the structure itself is opaque to this file, but that
- the user can use the regsets provided here. */
-
-struct propagate_block_info *
-init_propagate_block_info (bb, live, local_set, cond_local_set, flags)
- basic_block bb;
- regset live, local_set, cond_local_set;
- int flags;
-{
- struct propagate_block_info *pbi = xmalloc (sizeof (*pbi));
-
- pbi->bb = bb;
- pbi->reg_live = live;
- pbi->mem_set_list = NULL_RTX;
- pbi->mem_set_list_len = 0;
- pbi->local_set = local_set;
- pbi->cond_local_set = cond_local_set;
- pbi->cc0_live = 0;
- pbi->flags = flags;
-
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- pbi->reg_next_use = (rtx *) xcalloc (max_reg_num (), sizeof (rtx));
- else
- pbi->reg_next_use = NULL;
-
- pbi->new_set = BITMAP_XMALLOC ();
-
-#ifdef HAVE_conditional_execution
- pbi->reg_cond_dead = splay_tree_new (splay_tree_compare_ints, NULL,
- free_reg_cond_life_info);
- pbi->reg_cond_reg = BITMAP_XMALLOC ();
-
- /* If this block ends in a conditional branch, for each register live
- from one side of the branch and not the other, record the register
- as conditionally dead. */
- if (GET_CODE (bb->end) == JUMP_INSN
- && any_condjump_p (bb->end))
- {
- regset_head diff_head;
- regset diff = INITIALIZE_REG_SET (diff_head);
- basic_block bb_true, bb_false;
- rtx cond_true, cond_false, set_src;
- int i;
-
- /* Identify the successor blocks. */
- bb_true = bb->succ->dest;
- if (bb->succ->succ_next != NULL)
- {
- bb_false = bb->succ->succ_next->dest;
-
- if (bb->succ->flags & EDGE_FALLTHRU)
- {
- basic_block t = bb_false;
- bb_false = bb_true;
- bb_true = t;
- }
- else if (! (bb->succ->succ_next->flags & EDGE_FALLTHRU))
- abort ();
- }
- else
- {
- /* This can happen with a conditional jump to the next insn. */
- if (JUMP_LABEL (bb->end) != bb_true->head)
- abort ();
-
- /* Simplest way to do nothing. */
- bb_false = bb_true;
- }
-
- /* Extract the condition from the branch. */
- set_src = SET_SRC (pc_set (bb->end));
- cond_true = XEXP (set_src, 0);
- cond_false = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
- GET_MODE (cond_true), XEXP (cond_true, 0),
- XEXP (cond_true, 1));
- if (GET_CODE (XEXP (set_src, 1)) == PC)
- {
- rtx t = cond_false;
- cond_false = cond_true;
- cond_true = t;
- }
-
- /* Compute which register lead different lives in the successors. */
- if (bitmap_operation (diff, bb_true->global_live_at_start,
- bb_false->global_live_at_start, BITMAP_XOR))
- {
- rtx reg = XEXP (cond_true, 0);
-
- if (GET_CODE (reg) == SUBREG)
- reg = SUBREG_REG (reg);
-
- if (GET_CODE (reg) != REG)
- abort ();
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (reg));
-
- /* For each such register, mark it conditionally dead. */
- EXECUTE_IF_SET_IN_REG_SET
- (diff, 0, i,
- {
- struct reg_cond_life_info *rcli;
- rtx cond;
-
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
-
- if (REGNO_REG_SET_P (bb_true->global_live_at_start, i))
- cond = cond_false;
- else
- cond = cond_true;
- rcli->condition = cond;
- rcli->stores = const0_rtx;
- rcli->orig_condition = cond;
-
- splay_tree_insert (pbi->reg_cond_dead, i,
- (splay_tree_value) rcli);
- });
- }
-
- FREE_REG_SET (diff);
- }
-#endif
-
- /* If this block has no successors, any stores to the frame that aren't
- used later in the block are dead. So make a pass over the block
- recording any such that are made and show them dead at the end. We do
- a very conservative and simple job here. */
- if (optimize
- && ! (TREE_CODE (TREE_TYPE (current_function_decl)) == FUNCTION_TYPE
- && (TYPE_RETURNS_STACK_DEPRESSED
- (TREE_TYPE (current_function_decl))))
- && (flags & PROP_SCAN_DEAD_CODE)
- && (bb->succ == NULL
- || (bb->succ->succ_next == NULL
- && bb->succ->dest == EXIT_BLOCK_PTR
- && ! current_function_calls_eh_return)))
- {
- rtx insn, set;
- for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
- if (GET_CODE (insn) == INSN
- && (set = single_set (insn))
- && GET_CODE (SET_DEST (set)) == MEM)
- {
- rtx mem = SET_DEST (set);
- rtx canon_mem = canon_rtx (mem);
-
- /* This optimization is performed by faking a store to the
- memory at the end of the block. This doesn't work for
- unchanging memories because multiple stores to unchanging
- memory is illegal and alias analysis doesn't consider it. */
- if (RTX_UNCHANGING_P (canon_mem))
- continue;
-
- if (XEXP (canon_mem, 0) == frame_pointer_rtx
- || (GET_CODE (XEXP (canon_mem, 0)) == PLUS
- && XEXP (XEXP (canon_mem, 0), 0) == frame_pointer_rtx
- && GET_CODE (XEXP (XEXP (canon_mem, 0), 1)) == CONST_INT))
- add_to_mem_set_list (pbi, canon_mem);
- }
- }
-
- return pbi;
-}
-
-/* Release a propagate_block_info struct. */
-
-void
-free_propagate_block_info (pbi)
- struct propagate_block_info *pbi;
-{
- free_EXPR_LIST_list (&pbi->mem_set_list);
-
- BITMAP_XFREE (pbi->new_set);
-
-#ifdef HAVE_conditional_execution
- splay_tree_delete (pbi->reg_cond_dead);
- BITMAP_XFREE (pbi->reg_cond_reg);
-#endif
-
- if (pbi->reg_next_use)
- free (pbi->reg_next_use);
-
- free (pbi);
-}
-
-/* Compute the registers live at the beginning of a basic block BB from
- those live at the end.
-
- When called, REG_LIVE contains those live at the end. On return, it
- contains those live at the beginning.
-
- LOCAL_SET, if non-null, will be set with all registers killed
- unconditionally by this basic block.
- Likewise, COND_LOCAL_SET, if non-null, will be set with all registers
- killed conditionally by this basic block. If there is any unconditional
- set of a register, then the corresponding bit will be set in LOCAL_SET
- and cleared in COND_LOCAL_SET.
- It is valid for LOCAL_SET and COND_LOCAL_SET to be the same set. In this
- case, the resulting set will be equal to the union of the two sets that
- would otherwise be computed.
-
- Return non-zero if an INSN is deleted (i.e. by dead code removal). */
-
-int
-propagate_block (bb, live, local_set, cond_local_set, flags)
- basic_block bb;
- regset live;
- regset local_set;
- regset cond_local_set;
- int flags;
-{
- struct propagate_block_info *pbi;
- rtx insn, prev;
- int changed;
-
- pbi = init_propagate_block_info (bb, live, local_set, cond_local_set, flags);
-
- if (flags & PROP_REG_INFO)
- {
- int i;
-
- /* Process the regs live at the end of the block.
- Mark them as not local to any one basic block. */
- EXECUTE_IF_SET_IN_REG_SET (live, 0, i,
- { REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
- }
-
- /* Scan the block an insn at a time from end to beginning. */
-
- changed = 0;
- for (insn = bb->end;; insn = prev)
- {
- /* If this is a call to `setjmp' et al, warn if any
- non-volatile datum is live. */
- if ((flags & PROP_REG_INFO)
- && GET_CODE (insn) == CALL_INSN
- && find_reg_note (insn, REG_SETJMP, NULL))
- IOR_REG_SET (regs_live_at_setjmp, pbi->reg_live);
-
- prev = propagate_one_insn (pbi, insn);
- changed |= NEXT_INSN (prev) != insn;
-
- if (insn == bb->head)
- break;
- }
-
- free_propagate_block_info (pbi);
-
- return changed;
-}
-\f
-/* Return 1 if X (the body of an insn, or part of it) is just dead stores
- (SET expressions whose destinations are registers dead after the insn).
- NEEDED is the regset that says which regs are alive after the insn.
-
- Unless CALL_OK is non-zero, an insn is needed if it contains a CALL.
-
- If X is the entire body of an insn, NOTES contains the reg notes
- pertaining to the insn. */
-
-static int
-insn_dead_p (pbi, x, call_ok, notes)
- struct propagate_block_info *pbi;
- rtx x;
- int call_ok;
- rtx notes ATTRIBUTE_UNUSED;
-{
- enum rtx_code code = GET_CODE (x);
-
-#ifdef AUTO_INC_DEC
- /* As flow is invoked after combine, we must take existing AUTO_INC
- expressions into account. */
- for (; notes; notes = XEXP (notes, 1))
- {
- if (REG_NOTE_KIND (notes) == REG_INC)
- {
- int regno = REGNO (XEXP (notes, 0));
-
- /* Don't delete insns to set global regs. */
- if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- || REGNO_REG_SET_P (pbi->reg_live, regno))
- return 0;
- }
- }
-#endif
-
- /* If setting something that's a reg or part of one,
- see if that register's altered value will be live. */
-
- if (code == SET)
- {
- rtx r = SET_DEST (x);
-
-#ifdef HAVE_cc0
- if (GET_CODE (r) == CC0)
- return ! pbi->cc0_live;
-#endif
-
- /* A SET that is a subroutine call cannot be dead. */
- if (GET_CODE (SET_SRC (x)) == CALL)
- {
- if (! call_ok)
- return 0;
- }
-
- /* Don't eliminate loads from volatile memory or volatile asms. */
- else if (volatile_refs_p (SET_SRC (x)))
- return 0;
-
- if (GET_CODE (r) == MEM)
- {
- rtx temp, canon_r;
-
- if (MEM_VOLATILE_P (r) || GET_MODE (r) == BLKmode)
- return 0;
-
- canon_r = canon_rtx (r);
-
- /* Walk the set of memory locations we are currently tracking
- and see if one is an identical match to this memory location.
- If so, this memory write is dead (remember, we're walking
- backwards from the end of the block to the start). Since
- rtx_equal_p does not check the alias set or flags, we also
- must have the potential for them to conflict (anti_dependence). */
- for (temp = pbi->mem_set_list; temp != 0; temp = XEXP (temp, 1))
- if (anti_dependence (r, XEXP (temp, 0)))
- {
- rtx mem = XEXP (temp, 0);
-
- if (rtx_equal_p (XEXP (canon_r, 0), XEXP (mem, 0))
- && (GET_MODE_SIZE (GET_MODE (canon_r))
- <= GET_MODE_SIZE (GET_MODE (mem))))
- return 1;
-
-#ifdef AUTO_INC_DEC
- /* Check if memory reference matches an auto increment. Only
- post increment/decrement or modify are valid. */
- if (GET_MODE (mem) == GET_MODE (r)
- && (GET_CODE (XEXP (mem, 0)) == POST_DEC
- || GET_CODE (XEXP (mem, 0)) == POST_INC
- || GET_CODE (XEXP (mem, 0)) == POST_MODIFY)
- && GET_MODE (XEXP (mem, 0)) == GET_MODE (r)
- && rtx_equal_p (XEXP (XEXP (mem, 0), 0), XEXP (r, 0)))
- return 1;
-#endif
- }
- }
- else
- {
- while (GET_CODE (r) == SUBREG
- || GET_CODE (r) == STRICT_LOW_PART
- || GET_CODE (r) == ZERO_EXTRACT)
- r = XEXP (r, 0);
-
- if (GET_CODE (r) == REG)
- {
- int regno = REGNO (r);
-
- /* Obvious. */
- if (REGNO_REG_SET_P (pbi->reg_live, regno))
- return 0;
-
- /* If this is a hard register, verify that subsequent
- words are not needed. */
- if (regno < FIRST_PSEUDO_REGISTER)
- {
- int n = HARD_REGNO_NREGS (regno, GET_MODE (r));
-
- while (--n > 0)
- if (REGNO_REG_SET_P (pbi->reg_live, regno+n))
- return 0;
- }
-
- /* Don't delete insns to set global regs. */
- if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
- return 0;
-
- /* Make sure insns to set the stack pointer aren't deleted. */
- if (regno == STACK_POINTER_REGNUM)
- return 0;
-
- /* ??? These bits might be redundant with the force live bits
- in calculate_global_regs_live. We would delete from
- sequential sets; whether this actually affects real code
- for anything but the stack pointer I don't know. */
- /* Make sure insns to set the frame pointer aren't deleted. */
- if (regno == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
- return 0;
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- if (regno == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
- return 0;
-#endif
-
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- /* Make sure insns to set arg pointer are never deleted
- (if the arg pointer isn't fixed, there will be a USE
- for it, so we can treat it normally). */
- if (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
- return 0;
-#endif
-
- /* Otherwise, the set is dead. */
- return 1;
- }
- }
- }
-
- /* If performing several activities, insn is dead if each activity
- is individually dead. Also, CLOBBERs and USEs can be ignored; a
- CLOBBER or USE that's inside a PARALLEL doesn't make the insn
- worth keeping. */
- else if (code == PARALLEL)
- {
- int i = XVECLEN (x, 0);
-
- for (i--; i >= 0; i--)
- if (GET_CODE (XVECEXP (x, 0, i)) != CLOBBER
- && GET_CODE (XVECEXP (x, 0, i)) != USE
- && ! insn_dead_p (pbi, XVECEXP (x, 0, i), call_ok, NULL_RTX))
- return 0;
-
- return 1;
- }
-
- /* A CLOBBER of a pseudo-register that is dead serves no purpose. That
- is not necessarily true for hard registers. */
- else if (code == CLOBBER && GET_CODE (XEXP (x, 0)) == REG
- && REGNO (XEXP (x, 0)) >= FIRST_PSEUDO_REGISTER
- && ! REGNO_REG_SET_P (pbi->reg_live, REGNO (XEXP (x, 0))))
- return 1;
-
- /* We do not check other CLOBBER or USE here. An insn consisting of just
- a CLOBBER or just a USE should not be deleted. */
- return 0;
-}
-
-/* If INSN is the last insn in a libcall, and assuming INSN is dead,
- return 1 if the entire library call is dead.
- This is true if INSN copies a register (hard or pseudo)
- and if the hard return reg of the call insn is dead.
- (The caller should have tested the destination of the SET inside
- INSN already for death.)
-
- If this insn doesn't just copy a register, then we don't
- have an ordinary libcall. In that case, cse could not have
- managed to substitute the source for the dest later on,
- so we can assume the libcall is dead.
-
- PBI is the block info giving pseudoregs live before this insn.
- NOTE is the REG_RETVAL note of the insn. */
-
-static int
-libcall_dead_p (pbi, note, insn)
- struct propagate_block_info *pbi;
- rtx note;
- rtx insn;
-{
- rtx x = single_set (insn);
-
- if (x)
- {
- rtx r = SET_SRC (x);
-
- if (GET_CODE (r) == REG)
- {
- rtx call = XEXP (note, 0);
- rtx call_pat;
- int i;
-
- /* Find the call insn. */
- while (call != insn && GET_CODE (call) != CALL_INSN)
- call = NEXT_INSN (call);
-
- /* If there is none, do nothing special,
- since ordinary death handling can understand these insns. */
- if (call == insn)
- return 0;
-
- /* See if the hard reg holding the value is dead.
- If this is a PARALLEL, find the call within it. */
- call_pat = PATTERN (call);
- if (GET_CODE (call_pat) == PARALLEL)
- {
- for (i = XVECLEN (call_pat, 0) - 1; i >= 0; i--)
- if (GET_CODE (XVECEXP (call_pat, 0, i)) == SET
- && GET_CODE (SET_SRC (XVECEXP (call_pat, 0, i))) == CALL)
- break;
-
- /* This may be a library call that is returning a value
- via invisible pointer. Do nothing special, since
- ordinary death handling can understand these insns. */
- if (i < 0)
- return 0;
-
- call_pat = XVECEXP (call_pat, 0, i);
- }
-
- return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
- }
- }
- return 1;
-}
-
-/* Return 1 if register REGNO was used before it was set, i.e. if it is
- live at function entry. Don't count global register variables, variables
- in registers that can be used for function arg passing, or variables in
- fixed hard registers. */
-
-int
-regno_uninitialized (regno)
- unsigned int regno;
-{
- if (n_basic_blocks == 0
- || (regno < FIRST_PSEUDO_REGISTER
- && (global_regs[regno]
- || fixed_regs[regno]
- || FUNCTION_ARG_REGNO_P (regno))))
- return 0;
-
- return REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno);
-}
-
-/* 1 if register REGNO was alive at a place where `setjmp' was called
- and was set more than once or is an argument.
- Such regs may be clobbered by `longjmp'. */
-
-int
-regno_clobbered_at_setjmp (regno)
- int regno;
-{
- if (n_basic_blocks == 0)
- return 0;
-
- return ((REG_N_SETS (regno) > 1
- || REGNO_REG_SET_P (BASIC_BLOCK (0)->global_live_at_start, regno))
- && REGNO_REG_SET_P (regs_live_at_setjmp, regno));
-}
-\f
-/* Add MEM to PBI->MEM_SET_LIST. MEM should be canonical. Respect the
- maximal list size; look for overlaps in mode and select the largest. */
-static void
-add_to_mem_set_list (pbi, mem)
- struct propagate_block_info *pbi;
- rtx mem;
-{
- rtx i;
-
- /* We don't know how large a BLKmode store is, so we must not
- take them into consideration. */
- if (GET_MODE (mem) == BLKmode)
- return;
-
- for (i = pbi->mem_set_list; i ; i = XEXP (i, 1))
- {
- rtx e = XEXP (i, 0);
- if (rtx_equal_p (XEXP (mem, 0), XEXP (e, 0)))
- {
- if (GET_MODE_SIZE (GET_MODE (mem)) > GET_MODE_SIZE (GET_MODE (e)))
- {
-#ifdef AUTO_INC_DEC
- /* If we must store a copy of the mem, we can just modify
- the mode of the stored copy. */
- if (pbi->flags & PROP_AUTOINC)
- PUT_MODE (e, GET_MODE (mem));
- else
-#endif
- XEXP (i, 0) = mem;
- }
- return;
- }
- }
-
- if (pbi->mem_set_list_len < MAX_MEM_SET_LIST_LEN)
- {
-#ifdef AUTO_INC_DEC
- /* Store a copy of mem, otherwise the address may be
- scrogged by find_auto_inc. */
- if (pbi->flags & PROP_AUTOINC)
- mem = shallow_copy_rtx (mem);
-#endif
- pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
- pbi->mem_set_list_len++;
- }
-}
-
-/* INSN references memory, possibly using autoincrement addressing modes.
- Find any entries on the mem_set_list that need to be invalidated due
- to an address change. */
-
-static void
-invalidate_mems_from_autoinc (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- rtx note = REG_NOTES (insn);
- for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_INC)
- invalidate_mems_from_set (pbi, XEXP (note, 0));
-}
-
-/* EXP is a REG. Remove any dependent entries from pbi->mem_set_list. */
-
-static void
-invalidate_mems_from_set (pbi, exp)
- struct propagate_block_info *pbi;
- rtx exp;
-{
- rtx temp = pbi->mem_set_list;
- rtx prev = NULL_RTX;
- rtx next;
-
- while (temp)
- {
- next = XEXP (temp, 1);
- if (reg_overlap_mentioned_p (exp, XEXP (temp, 0)))
- {
- /* Splice this entry out of the list. */
- if (prev)
- XEXP (prev, 1) = next;
- else
- pbi->mem_set_list = next;
- free_EXPR_LIST_node (temp);
- pbi->mem_set_list_len--;
- }
- else
- prev = temp;
- temp = next;
- }
-}
-
-/* Process the registers that are set within X. Their bits are set to
- 1 in the regset DEAD, because they are dead prior to this insn.
-
- If INSN is nonzero, it is the insn being processed.
-
- FLAGS is the set of operations to perform. */
-
-static void
-mark_set_regs (pbi, x, insn)
- struct propagate_block_info *pbi;
- rtx x, insn;
-{
- rtx cond = NULL_RTX;
- rtx link;
- enum rtx_code code;
-
- if (insn)
- for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
- {
- if (REG_NOTE_KIND (link) == REG_INC)
- mark_set_1 (pbi, SET, XEXP (link, 0),
- (GET_CODE (x) == COND_EXEC
- ? COND_EXEC_TEST (x) : NULL_RTX),
- insn, pbi->flags);
- }
- retry:
- switch (code = GET_CODE (x))
- {
- case SET:
- case CLOBBER:
- mark_set_1 (pbi, code, SET_DEST (x), cond, insn, pbi->flags);
- return;
-
- case COND_EXEC:
- cond = COND_EXEC_TEST (x);
- x = COND_EXEC_CODE (x);
- goto retry;
-
- case PARALLEL:
- {
- int i;
-
- for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
- {
- rtx sub = XVECEXP (x, 0, i);
- switch (code = GET_CODE (sub))
- {
- case COND_EXEC:
- if (cond != NULL_RTX)
- abort ();
-
- cond = COND_EXEC_TEST (sub);
- sub = COND_EXEC_CODE (sub);
- if (GET_CODE (sub) != SET && GET_CODE (sub) != CLOBBER)
- break;
- /* Fall through. */
-
- case SET:
- case CLOBBER:
- mark_set_1 (pbi, code, SET_DEST (sub), cond, insn, pbi->flags);
- break;
-
- default:
- break;
- }
- }
- break;
- }
-
- default:
- break;
- }
-}
-
-/* Process a single set, which appears in INSN. REG (which may not
- actually be a REG, it may also be a SUBREG, PARALLEL, etc.) is
- being set using the CODE (which may be SET, CLOBBER, or COND_EXEC).
- If the set is conditional (because it appear in a COND_EXEC), COND
- will be the condition. */
-
-static void
-mark_set_1 (pbi, code, reg, cond, insn, flags)
- struct propagate_block_info *pbi;
- enum rtx_code code;
- rtx reg, cond, insn;
- int flags;
-{
- int regno_first = -1, regno_last = -1;
- unsigned long not_dead = 0;
- int i;
-
- /* Modifying just one hardware register of a multi-reg value or just a
- byte field of a register does not mean the value from before this insn
- is now dead. Of course, if it was dead after it's unused now. */
-
- switch (GET_CODE (reg))
- {
- case PARALLEL:
- /* Some targets place small structures in registers for return values of
- functions. We have to detect this case specially here to get correct
- flow information. */
- for (i = XVECLEN (reg, 0) - 1; i >= 0; i--)
- if (XEXP (XVECEXP (reg, 0, i), 0) != 0)
- mark_set_1 (pbi, code, XEXP (XVECEXP (reg, 0, i), 0), cond, insn,
- flags);
- return;
-
- case ZERO_EXTRACT:
- case SIGN_EXTRACT:
- case STRICT_LOW_PART:
- /* ??? Assumes STRICT_LOW_PART not used on multi-word registers. */
- do
- reg = XEXP (reg, 0);
- while (GET_CODE (reg) == SUBREG
- || GET_CODE (reg) == ZERO_EXTRACT
- || GET_CODE (reg) == SIGN_EXTRACT
- || GET_CODE (reg) == STRICT_LOW_PART);
- if (GET_CODE (reg) == MEM)
- break;
- not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live, REGNO (reg));
- /* Fall through. */
-
- case REG:
- regno_last = regno_first = REGNO (reg);
- if (regno_first < FIRST_PSEUDO_REGISTER)
- regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
- break;
-
- case SUBREG:
- if (GET_CODE (SUBREG_REG (reg)) == REG)
- {
- enum machine_mode outer_mode = GET_MODE (reg);
- enum machine_mode inner_mode = GET_MODE (SUBREG_REG (reg));
-
- /* Identify the range of registers affected. This is moderately
- tricky for hard registers. See alter_subreg. */
-
- regno_last = regno_first = REGNO (SUBREG_REG (reg));
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- regno_first += subreg_regno_offset (regno_first, inner_mode,
- SUBREG_BYTE (reg),
- outer_mode);
- regno_last = (regno_first
- + HARD_REGNO_NREGS (regno_first, outer_mode) - 1);
-
- /* Since we've just adjusted the register number ranges, make
- sure REG matches. Otherwise some_was_live will be clear
- when it shouldn't have been, and we'll create incorrect
- REG_UNUSED notes. */
- reg = gen_rtx_REG (outer_mode, regno_first);
- }
- else
- {
- /* If the number of words in the subreg is less than the number
- of words in the full register, we have a well-defined partial
- set. Otherwise the high bits are undefined.
-
- This is only really applicable to pseudos, since we just took
- care of multi-word hard registers. */
- if (((GET_MODE_SIZE (outer_mode)
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
- < ((GET_MODE_SIZE (inner_mode)
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
- not_dead = (unsigned long) REGNO_REG_SET_P (pbi->reg_live,
- regno_first);
-
- reg = SUBREG_REG (reg);
- }
- }
- else
- reg = SUBREG_REG (reg);
- break;
-
- default:
- break;
- }
-
- /* If this set is a MEM, then it kills any aliased writes.
- If this set is a REG, then it kills any MEMs which use the reg. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- {
- if (GET_CODE (reg) == REG)
- invalidate_mems_from_set (pbi, reg);
-
- /* If the memory reference had embedded side effects (autoincrement
- address modes. Then we may need to kill some entries on the
- memory set list. */
- if (insn && GET_CODE (reg) == MEM)
- invalidate_mems_from_autoinc (pbi, insn);
-
- if (GET_CODE (reg) == MEM && ! side_effects_p (reg)
- /* ??? With more effort we could track conditional memory life. */
- && ! cond
- /* There are no REG_INC notes for SP, so we can't assume we'll see
- everything that invalidates it. To be safe, don't eliminate any
- stores though SP; none of them should be redundant anyway. */
- && ! reg_mentioned_p (stack_pointer_rtx, reg))
- add_to_mem_set_list (pbi, canon_rtx (reg));
- }
-
- if (GET_CODE (reg) == REG
- && ! (regno_first == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && ! (regno_first == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno_first == ARG_POINTER_REGNUM && fixed_regs[regno_first])
-#endif
- )
- {
- int some_was_live = 0, some_was_dead = 0;
-
- for (i = regno_first; i <= regno_last; ++i)
- {
- int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
- if (pbi->local_set)
- {
- /* Order of the set operation matters here since both
- sets may be the same. */
- CLEAR_REGNO_REG_SET (pbi->cond_local_set, i);
- if (cond != NULL_RTX
- && ! REGNO_REG_SET_P (pbi->local_set, i))
- SET_REGNO_REG_SET (pbi->cond_local_set, i);
- else
- SET_REGNO_REG_SET (pbi->local_set, i);
- }
- if (code != CLOBBER)
- SET_REGNO_REG_SET (pbi->new_set, i);
-
- some_was_live |= needed_regno;
- some_was_dead |= ! needed_regno;
- }
-
-#ifdef HAVE_conditional_execution
- /* Consider conditional death in deciding that the register needs
- a death note. */
- if (some_was_live && ! not_dead
- /* The stack pointer is never dead. Well, not strictly true,
- but it's very difficult to tell from here. Hopefully
- combine_stack_adjustments will fix up the most egregious
- errors. */
- && regno_first != STACK_POINTER_REGNUM)
- {
- for (i = regno_first; i <= regno_last; ++i)
- if (! mark_regno_cond_dead (pbi, i, cond))
- not_dead |= ((unsigned long) 1) << (i - regno_first);
- }
-#endif
-
- /* Additional data to record if this is the final pass. */
- if (flags & (PROP_LOG_LINKS | PROP_REG_INFO
- | PROP_DEATH_NOTES | PROP_AUTOINC))
- {
- rtx y;
- int blocknum = pbi->bb->index;
-
- y = NULL_RTX;
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- {
- y = pbi->reg_next_use[regno_first];
-
- /* The next use is no longer next, since a store intervenes. */
- for (i = regno_first; i <= regno_last; ++i)
- pbi->reg_next_use[i] = 0;
- }
-
- if (flags & PROP_REG_INFO)
- {
- for (i = regno_first; i <= regno_last; ++i)
- {
- /* Count (weighted) references, stores, etc. This counts a
- register twice if it is modified, but that is correct. */
- REG_N_SETS (i) += 1;
- REG_N_REFS (i) += 1;
- REG_FREQ (i) += REG_FREQ_FROM_BB (pbi->bb);
-
- /* The insns where a reg is live are normally counted
- elsewhere, but we want the count to include the insn
- where the reg is set, and the normal counting mechanism
- would not count it. */
- REG_LIVE_LENGTH (i) += 1;
- }
-
- /* If this is a hard reg, record this function uses the reg. */
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- for (i = regno_first; i <= regno_last; i++)
- regs_ever_live[i] = 1;
- }
- else
- {
- /* Keep track of which basic blocks each reg appears in. */
- if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno_first) = blocknum;
- else if (REG_BASIC_BLOCK (regno_first) != blocknum)
- REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
- }
- }
-
- if (! some_was_dead)
- {
- if (flags & PROP_LOG_LINKS)
- {
- /* Make a logical link from the next following insn
- that uses this register, back to this insn.
- The following insns have already been processed.
-
- We don't build a LOG_LINK for hard registers containing
- in ASM_OPERANDs. If these registers get replaced,
- we might wind up changing the semantics of the insn,
- even if reload can make what appear to be valid
- assignments later. */
- if (y && (BLOCK_NUM (y) == blocknum)
- && (regno_first >= FIRST_PSEUDO_REGISTER
- || asm_noperands (PATTERN (y)) < 0))
- LOG_LINKS (y) = alloc_INSN_LIST (insn, LOG_LINKS (y));
- }
- }
- else if (not_dead)
- ;
- else if (! some_was_live)
- {
- if (flags & PROP_REG_INFO)
- REG_N_DEATHS (regno_first) += 1;
-
- if (flags & PROP_DEATH_NOTES)
- {
- /* Note that dead stores have already been deleted
- when possible. If we get here, we have found a
- dead store that cannot be eliminated (because the
- same insn does something useful). Indicate this
- by marking the reg being set as dying here. */
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
- }
- }
- else
- {
- if (flags & PROP_DEATH_NOTES)
- {
- /* This is a case where we have a multi-word hard register
- and some, but not all, of the words of the register are
- needed in subsequent insns. Write REG_UNUSED notes
- for those parts that were not needed. This case should
- be rare. */
-
- for (i = regno_first; i <= regno_last; ++i)
- if (! REGNO_REG_SET_P (pbi->reg_live, i))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED,
- gen_rtx_REG (reg_raw_mode[i], i),
- REG_NOTES (insn));
- }
- }
- }
-
- /* Mark the register as being dead. */
- if (some_was_live
- /* The stack pointer is never dead. Well, not strictly true,
- but it's very difficult to tell from here. Hopefully
- combine_stack_adjustments will fix up the most egregious
- errors. */
- && regno_first != STACK_POINTER_REGNUM)
- {
- for (i = regno_first; i <= regno_last; ++i)
- if (!(not_dead & (((unsigned long) 1) << (i - regno_first))))
- CLEAR_REGNO_REG_SET (pbi->reg_live, i);
- }
- }
- else if (GET_CODE (reg) == REG)
- {
- if (flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- pbi->reg_next_use[regno_first] = 0;
- }
-
- /* If this is the last pass and this is a SCRATCH, show it will be dying
- here and count it. */
- else if (GET_CODE (reg) == SCRATCH)
- {
- if (flags & PROP_DEATH_NOTES)
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_UNUSED, reg, REG_NOTES (insn));
- }
-}
-\f
-#ifdef HAVE_conditional_execution
-/* Mark REGNO conditionally dead.
- Return true if the register is now unconditionally dead. */
-
-static int
-mark_regno_cond_dead (pbi, regno, cond)
- struct propagate_block_info *pbi;
- int regno;
- rtx cond;
-{
- /* If this is a store to a predicate register, the value of the
- predicate is changing, we don't know that the predicate as seen
- before is the same as that seen after. Flush all dependent
- conditions from reg_cond_dead. This will make all such
- conditionally live registers unconditionally live. */
- if (REGNO_REG_SET_P (pbi->reg_cond_reg, regno))
- flush_reg_cond_reg (pbi, regno);
-
- /* If this is an unconditional store, remove any conditional
- life that may have existed. */
- if (cond == NULL_RTX)
- splay_tree_remove (pbi->reg_cond_dead, regno);
- else
- {
- splay_tree_node node;
- struct reg_cond_life_info *rcli;
- rtx ncond;
-
- /* Otherwise this is a conditional set. Record that fact.
- It may have been conditionally used, or there may be a
- subsequent set with a complimentary condition. */
-
- node = splay_tree_lookup (pbi->reg_cond_dead, regno);
- if (node == NULL)
- {
- /* The register was unconditionally live previously.
- Record the current condition as the condition under
- which it is dead. */
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
- rcli->condition = cond;
- rcli->stores = cond;
- rcli->orig_condition = const0_rtx;
- splay_tree_insert (pbi->reg_cond_dead, regno,
- (splay_tree_value) rcli);
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
-
- /* Not unconditionally dead. */
- return 0;
- }
- else
- {
- /* The register was conditionally live previously.
- Add the new condition to the old. */
- rcli = (struct reg_cond_life_info *) node->value;
- ncond = rcli->condition;
- ncond = ior_reg_cond (ncond, cond, 1);
- if (rcli->stores == const0_rtx)
- rcli->stores = cond;
- else if (rcli->stores != const1_rtx)
- rcli->stores = ior_reg_cond (rcli->stores, cond, 1);
-
- /* If the register is now unconditionally dead, remove the entry
- in the splay_tree. A register is unconditionally dead if the
- dead condition ncond is true. A register is also unconditionally
- dead if the sum of all conditional stores is an unconditional
- store (stores is true), and the dead condition is identically the
- same as the original dead condition initialized at the end of
- the block. This is a pointer compare, not an rtx_equal_p
- compare. */
- if (ncond == const1_rtx
- || (ncond == rcli->orig_condition && rcli->stores == const1_rtx))
- splay_tree_remove (pbi->reg_cond_dead, regno);
- else
- {
- rcli->condition = ncond;
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
-
- /* Not unconditionally dead. */
- return 0;
- }
- }
- }
-
- return 1;
-}
-
-/* Called from splay_tree_delete for pbi->reg_cond_life. */
-
-static void
-free_reg_cond_life_info (value)
- splay_tree_value value;
-{
- struct reg_cond_life_info *rcli = (struct reg_cond_life_info *) value;
- free (rcli);
-}
-
-/* Helper function for flush_reg_cond_reg. */
-
-static int
-flush_reg_cond_reg_1 (node, data)
- splay_tree_node node;
- void *data;
-{
- struct reg_cond_life_info *rcli;
- int *xdata = (int *) data;
- unsigned int regno = xdata[0];
-
- /* Don't need to search if last flushed value was farther on in
- the in-order traversal. */
- if (xdata[1] >= (int) node->key)
- return 0;
-
- /* Splice out portions of the expression that refer to regno. */
- rcli = (struct reg_cond_life_info *) node->value;
- rcli->condition = elim_reg_cond (rcli->condition, regno);
- if (rcli->stores != const0_rtx && rcli->stores != const1_rtx)
- rcli->stores = elim_reg_cond (rcli->stores, regno);
-
- /* If the entire condition is now false, signal the node to be removed. */
- if (rcli->condition == const0_rtx)
- {
- xdata[1] = node->key;
- return -1;
- }
- else if (rcli->condition == const1_rtx)
- abort ();
-
- return 0;
-}
-
-/* Flush all (sub) expressions referring to REGNO from REG_COND_LIVE. */
-
-static void
-flush_reg_cond_reg (pbi, regno)
- struct propagate_block_info *pbi;
- int regno;
-{
- int pair[2];
-
- pair[0] = regno;
- pair[1] = -1;
- while (splay_tree_foreach (pbi->reg_cond_dead,
- flush_reg_cond_reg_1, pair) == -1)
- splay_tree_remove (pbi->reg_cond_dead, pair[1]);
-
- CLEAR_REGNO_REG_SET (pbi->reg_cond_reg, regno);
-}
-
-/* Logical arithmetic on predicate conditions. IOR, NOT and AND.
- For ior/and, the ADD flag determines whether we want to add the new
- condition X to the old one unconditionally. If it is zero, we will
- only return a new expression if X allows us to simplify part of
- OLD, otherwise we return NULL to the caller.
- If ADD is nonzero, we will return a new condition in all cases. The
- toplevel caller of one of these functions should always pass 1 for
- ADD. */
-
-static rtx
-ior_reg_cond (old, x, add)
- rtx old, x;
- int add;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (old)) == '<')
- {
- if (GET_RTX_CLASS (GET_CODE (x)) == '<'
- && REVERSE_CONDEXEC_PREDICATES_P (GET_CODE (x), GET_CODE (old))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return const1_rtx;
- if (GET_CODE (x) == GET_CODE (old)
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return old;
- if (! add)
- return NULL;
- return gen_rtx_IOR (0, old, x);
- }
-
- switch (GET_CODE (old))
- {
- case IOR:
- op0 = ior_reg_cond (XEXP (old, 0), x, 0);
- op1 = ior_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != NULL || op1 != NULL)
- {
- if (op0 == const0_rtx)
- return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
- if (op1 == const0_rtx)
- return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == NULL)
- op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
- else if (rtx_equal_p (x, op0))
- /* (x | A) | x ~ (x | A). */
- return old;
- if (op1 == NULL)
- op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
- else if (rtx_equal_p (x, op1))
- /* (A | x) | x ~ (A | x). */
- return old;
- return gen_rtx_IOR (0, op0, op1);
- }
- if (! add)
- return NULL;
- return gen_rtx_IOR (0, old, x);
-
- case AND:
- op0 = ior_reg_cond (XEXP (old, 0), x, 0);
- op1 = ior_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != NULL || op1 != NULL)
- {
- if (op0 == const1_rtx)
- return op1 ? op1 : gen_rtx_IOR (0, XEXP (old, 1), x);
- if (op1 == const1_rtx)
- return op0 ? op0 : gen_rtx_IOR (0, XEXP (old, 0), x);
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == NULL)
- op0 = gen_rtx_IOR (0, XEXP (old, 0), x);
- else if (rtx_equal_p (x, op0))
- /* (x & A) | x ~ x. */
- return op0;
- if (op1 == NULL)
- op1 = gen_rtx_IOR (0, XEXP (old, 1), x);
- else if (rtx_equal_p (x, op1))
- /* (A & x) | x ~ x. */
- return op1;
- return gen_rtx_AND (0, op0, op1);
- }
- if (! add)
- return NULL;
- return gen_rtx_IOR (0, old, x);
-
- case NOT:
- op0 = and_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
- if (op0 != NULL)
- return not_reg_cond (op0);
- if (! add)
- return NULL;
- return gen_rtx_IOR (0, old, x);
-
- default:
- abort ();
- }
-}
-
-static rtx
-not_reg_cond (x)
- rtx x;
-{
- enum rtx_code x_code;
-
- if (x == const0_rtx)
- return const1_rtx;
- else if (x == const1_rtx)
- return const0_rtx;
- x_code = GET_CODE (x);
- if (x_code == NOT)
- return XEXP (x, 0);
- if (GET_RTX_CLASS (x_code) == '<'
- && GET_CODE (XEXP (x, 0)) == REG)
- {
- if (XEXP (x, 1) != const0_rtx)
- abort ();
-
- return gen_rtx_fmt_ee (reverse_condition (x_code),
- VOIDmode, XEXP (x, 0), const0_rtx);
- }
- return gen_rtx_NOT (0, x);
-}
-
-static rtx
-and_reg_cond (old, x, add)
- rtx old, x;
- int add;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (old)) == '<')
- {
- if (GET_RTX_CLASS (GET_CODE (x)) == '<'
- && GET_CODE (x) == reverse_condition (GET_CODE (old))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return const0_rtx;
- if (GET_CODE (x) == GET_CODE (old)
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (old, 0)))
- return old;
- if (! add)
- return NULL;
- return gen_rtx_AND (0, old, x);
- }
-
- switch (GET_CODE (old))
- {
- case IOR:
- op0 = and_reg_cond (XEXP (old, 0), x, 0);
- op1 = and_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != NULL || op1 != NULL)
- {
- if (op0 == const0_rtx)
- return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
- if (op1 == const0_rtx)
- return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == NULL)
- op0 = gen_rtx_AND (0, XEXP (old, 0), x);
- else if (rtx_equal_p (x, op0))
- /* (x | A) & x ~ x. */
- return op0;
- if (op1 == NULL)
- op1 = gen_rtx_AND (0, XEXP (old, 1), x);
- else if (rtx_equal_p (x, op1))
- /* (A | x) & x ~ x. */
- return op1;
- return gen_rtx_IOR (0, op0, op1);
- }
- if (! add)
- return NULL;
- return gen_rtx_AND (0, old, x);
-
- case AND:
- op0 = and_reg_cond (XEXP (old, 0), x, 0);
- op1 = and_reg_cond (XEXP (old, 1), x, 0);
- if (op0 != NULL || op1 != NULL)
- {
- if (op0 == const1_rtx)
- return op1 ? op1 : gen_rtx_AND (0, XEXP (old, 1), x);
- if (op1 == const1_rtx)
- return op0 ? op0 : gen_rtx_AND (0, XEXP (old, 0), x);
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == NULL)
- op0 = gen_rtx_AND (0, XEXP (old, 0), x);
- else if (rtx_equal_p (x, op0))
- /* (x & A) & x ~ (x & A). */
- return old;
- if (op1 == NULL)
- op1 = gen_rtx_AND (0, XEXP (old, 1), x);
- else if (rtx_equal_p (x, op1))
- /* (A & x) & x ~ (A & x). */
- return old;
- return gen_rtx_AND (0, op0, op1);
- }
- if (! add)
- return NULL;
- return gen_rtx_AND (0, old, x);
-
- case NOT:
- op0 = ior_reg_cond (XEXP (old, 0), not_reg_cond (x), 0);
- if (op0 != NULL)
- return not_reg_cond (op0);
- if (! add)
- return NULL;
- return gen_rtx_AND (0, old, x);
-
- default:
- abort ();
- }
-}
-
-/* Given a condition X, remove references to reg REGNO and return the
- new condition. The removal will be done so that all conditions
- involving REGNO are considered to evaluate to false. This function
- is used when the value of REGNO changes. */
-
-static rtx
-elim_reg_cond (x, regno)
- rtx x;
- unsigned int regno;
-{
- rtx op0, op1;
-
- if (GET_RTX_CLASS (GET_CODE (x)) == '<')
- {
- if (REGNO (XEXP (x, 0)) == regno)
- return const0_rtx;
- return x;
- }
-
- switch (GET_CODE (x))
- {
- case AND:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- op1 = elim_reg_cond (XEXP (x, 1), regno);
- if (op0 == const0_rtx || op1 == const0_rtx)
- return const0_rtx;
- if (op0 == const1_rtx)
- return op1;
- if (op1 == const1_rtx)
- return op0;
- if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
- return x;
- return gen_rtx_AND (0, op0, op1);
-
- case IOR:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- op1 = elim_reg_cond (XEXP (x, 1), regno);
- if (op0 == const1_rtx || op1 == const1_rtx)
- return const1_rtx;
- if (op0 == const0_rtx)
- return op1;
- if (op1 == const0_rtx)
- return op0;
- if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
- return x;
- return gen_rtx_IOR (0, op0, op1);
-
- case NOT:
- op0 = elim_reg_cond (XEXP (x, 0), regno);
- if (op0 == const0_rtx)
- return const1_rtx;
- if (op0 == const1_rtx)
- return const0_rtx;
- if (op0 != XEXP (x, 0))
- return not_reg_cond (op0);
- return x;
-
- default:
- abort ();
- }
-}
-#endif /* HAVE_conditional_execution */
-\f
-#ifdef AUTO_INC_DEC
-
-/* Try to substitute the auto-inc expression INC as the address inside
- MEM which occurs in INSN. Currently, the address of MEM is an expression
- involving INCR_REG, and INCR is the next use of INCR_REG; it is an insn
- that has a single set whose source is a PLUS of INCR_REG and something
- else. */
-
-static void
-attempt_auto_inc (pbi, inc, insn, mem, incr, incr_reg)
- struct propagate_block_info *pbi;
- rtx inc, insn, mem, incr, incr_reg;
-{
- int regno = REGNO (incr_reg);
- rtx set = single_set (incr);
- rtx q = SET_DEST (set);
- rtx y = SET_SRC (set);
- int opnum = XEXP (y, 0) == incr_reg ? 0 : 1;
-
- /* Make sure this reg appears only once in this insn. */
- if (count_occurrences (PATTERN (insn), incr_reg, 1) != 1)
- return;
-
- if (dead_or_set_p (incr, incr_reg)
- /* Mustn't autoinc an eliminable register. */
- && (regno >= FIRST_PSEUDO_REGISTER
- || ! TEST_HARD_REG_BIT (elim_reg_set, regno)))
- {
- /* This is the simple case. Try to make the auto-inc. If
- we can't, we are done. Otherwise, we will do any
- needed updates below. */
- if (! validate_change (insn, &XEXP (mem, 0), inc, 0))
- return;
- }
- else if (GET_CODE (q) == REG
- /* PREV_INSN used here to check the semi-open interval
- [insn,incr). */
- && ! reg_used_between_p (q, PREV_INSN (insn), incr)
- /* We must also check for sets of q as q may be
- a call clobbered hard register and there may
- be a call between PREV_INSN (insn) and incr. */
- && ! reg_set_between_p (q, PREV_INSN (insn), incr))
- {
- /* We have *p followed sometime later by q = p+size.
- Both p and q must be live afterward,
- and q is not used between INSN and its assignment.
- Change it to q = p, ...*q..., q = q+size.
- Then fall into the usual case. */
- rtx insns, temp;
-
- start_sequence ();
- emit_move_insn (q, incr_reg);
- insns = get_insns ();
- end_sequence ();
-
- /* If we can't make the auto-inc, or can't make the
- replacement into Y, exit. There's no point in making
- the change below if we can't do the auto-inc and doing
- so is not correct in the pre-inc case. */
-
- XEXP (inc, 0) = q;
- validate_change (insn, &XEXP (mem, 0), inc, 1);
- validate_change (incr, &XEXP (y, opnum), q, 1);
- if (! apply_change_group ())
- return;
-
- /* We now know we'll be doing this change, so emit the
- new insn(s) and do the updates. */
- emit_insns_before (insns, insn);
-
- if (pbi->bb->head == insn)
- pbi->bb->head = insns;
-
- /* INCR will become a NOTE and INSN won't contain a
- use of INCR_REG. If a use of INCR_REG was just placed in
- the insn before INSN, make that the next use.
- Otherwise, invalidate it. */
- if (GET_CODE (PREV_INSN (insn)) == INSN
- && GET_CODE (PATTERN (PREV_INSN (insn))) == SET
- && SET_SRC (PATTERN (PREV_INSN (insn))) == incr_reg)
- pbi->reg_next_use[regno] = PREV_INSN (insn);
- else
- pbi->reg_next_use[regno] = 0;
-
- incr_reg = q;
- regno = REGNO (q);
-
- /* REGNO is now used in INCR which is below INSN, but
- it previously wasn't live here. If we don't mark
- it as live, we'll put a REG_DEAD note for it
- on this insn, which is incorrect. */
- SET_REGNO_REG_SET (pbi->reg_live, regno);
-
- /* If there are any calls between INSN and INCR, show
- that REGNO now crosses them. */
- for (temp = insn; temp != incr; temp = NEXT_INSN (temp))
- if (GET_CODE (temp) == CALL_INSN)
- REG_N_CALLS_CROSSED (regno)++;
-
- /* Invalidate alias info for Q since we just changed its value. */
- clear_reg_alias_info (q);
- }
- else
- return;
-
- /* If we haven't returned, it means we were able to make the
- auto-inc, so update the status. First, record that this insn
- has an implicit side effect. */
-
- REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, incr_reg, REG_NOTES (insn));
-
- /* Modify the old increment-insn to simply copy
- the already-incremented value of our register. */
- if (! validate_change (incr, &SET_SRC (set), incr_reg, 0))
- abort ();
-
- /* If that makes it a no-op (copying the register into itself) delete
- it so it won't appear to be a "use" and a "set" of this
- register. */
- if (REGNO (SET_DEST (set)) == REGNO (incr_reg))
- {
- /* If the original source was dead, it's dead now. */
- rtx note;
-
- while ((note = find_reg_note (incr, REG_DEAD, NULL_RTX)) != NULL_RTX)
- {
- remove_note (incr, note);
- if (XEXP (note, 0) != incr_reg)
- CLEAR_REGNO_REG_SET (pbi->reg_live, REGNO (XEXP (note, 0)));
- }
-
- PUT_CODE (incr, NOTE);
- NOTE_LINE_NUMBER (incr) = NOTE_INSN_DELETED;
- NOTE_SOURCE_FILE (incr) = 0;
- }
-
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- /* Count an extra reference to the reg. When a reg is
- incremented, spilling it is worse, so we want to make
- that less likely. */
- REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
-
- /* Count the increment as a setting of the register,
- even though it isn't a SET in rtl. */
- REG_N_SETS (regno)++;
- }
-}
-
-/* X is a MEM found in INSN. See if we can convert it into an auto-increment
- reference. */
-
-static void
-find_auto_inc (pbi, x, insn)
- struct propagate_block_info *pbi;
- rtx x;
- rtx insn;
-{
- rtx addr = XEXP (x, 0);
- HOST_WIDE_INT offset = 0;
- rtx set, y, incr, inc_val;
- int regno;
- int size = GET_MODE_SIZE (GET_MODE (x));
-
- if (GET_CODE (insn) == JUMP_INSN)
- return;
-
- /* Here we detect use of an index register which might be good for
- postincrement, postdecrement, preincrement, or predecrement. */
-
- if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
- offset = INTVAL (XEXP (addr, 1)), addr = XEXP (addr, 0);
-
- if (GET_CODE (addr) != REG)
- return;
-
- regno = REGNO (addr);
-
- /* Is the next use an increment that might make auto-increment? */
- incr = pbi->reg_next_use[regno];
- if (incr == 0 || BLOCK_NUM (incr) != BLOCK_NUM (insn))
- return;
- set = single_set (incr);
- if (set == 0 || GET_CODE (set) != SET)
- return;
- y = SET_SRC (set);
-
- if (GET_CODE (y) != PLUS)
- return;
-
- if (REG_P (XEXP (y, 0)) && REGNO (XEXP (y, 0)) == REGNO (addr))
- inc_val = XEXP (y, 1);
- else if (REG_P (XEXP (y, 1)) && REGNO (XEXP (y, 1)) == REGNO (addr))
- inc_val = XEXP (y, 0);
- else
- return;
-
- if (GET_CODE (inc_val) == CONST_INT)
- {
- if (HAVE_POST_INCREMENT
- && (INTVAL (inc_val) == size && offset == 0))
- attempt_auto_inc (pbi, gen_rtx_POST_INC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_POST_DECREMENT
- && (INTVAL (inc_val) == -size && offset == 0))
- attempt_auto_inc (pbi, gen_rtx_POST_DEC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_PRE_INCREMENT
- && (INTVAL (inc_val) == size && offset == size))
- attempt_auto_inc (pbi, gen_rtx_PRE_INC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_PRE_DECREMENT
- && (INTVAL (inc_val) == -size && offset == -size))
- attempt_auto_inc (pbi, gen_rtx_PRE_DEC (Pmode, addr), insn, x,
- incr, addr);
- else if (HAVE_POST_MODIFY_DISP && offset == 0)
- attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
- gen_rtx_PLUS (Pmode,
- addr,
- inc_val)),
- insn, x, incr, addr);
- }
- else if (GET_CODE (inc_val) == REG
- && ! reg_set_between_p (inc_val, PREV_INSN (insn),
- NEXT_INSN (incr)))
-
- {
- if (HAVE_POST_MODIFY_REG && offset == 0)
- attempt_auto_inc (pbi, gen_rtx_POST_MODIFY (Pmode, addr,
- gen_rtx_PLUS (Pmode,
- addr,
- inc_val)),
- insn, x, incr, addr);
- }
-}
-
-#endif /* AUTO_INC_DEC */
-\f
-static void
-mark_used_reg (pbi, reg, cond, insn)
- struct propagate_block_info *pbi;
- rtx reg;
- rtx cond ATTRIBUTE_UNUSED;
- rtx insn;
-{
- unsigned int regno_first, regno_last, i;
- int some_was_live, some_was_dead, some_not_set;
-
- regno_last = regno_first = REGNO (reg);
- if (regno_first < FIRST_PSEUDO_REGISTER)
- regno_last += HARD_REGNO_NREGS (regno_first, GET_MODE (reg)) - 1;
-
- /* Find out if any of this register is live after this instruction. */
- some_was_live = some_was_dead = 0;
- for (i = regno_first; i <= regno_last; ++i)
- {
- int needed_regno = REGNO_REG_SET_P (pbi->reg_live, i);
- some_was_live |= needed_regno;
- some_was_dead |= ! needed_regno;
- }
-
- /* Find out if any of the register was set this insn. */
- some_not_set = 0;
- for (i = regno_first; i <= regno_last; ++i)
- some_not_set |= ! REGNO_REG_SET_P (pbi->new_set, i);
-
- if (pbi->flags & (PROP_LOG_LINKS | PROP_AUTOINC))
- {
- /* Record where each reg is used, so when the reg is set we know
- the next insn that uses it. */
- pbi->reg_next_use[regno_first] = insn;
- }
-
- if (pbi->flags & PROP_REG_INFO)
- {
- if (regno_first < FIRST_PSEUDO_REGISTER)
- {
- /* If this is a register we are going to try to eliminate,
- don't mark it live here. If we are successful in
- eliminating it, it need not be live unless it is used for
- pseudos, in which case it will have been set live when it
- was allocated to the pseudos. If the register will not
- be eliminated, reload will set it live at that point.
-
- Otherwise, record that this function uses this register. */
- /* ??? The PPC backend tries to "eliminate" on the pic
- register to itself. This should be fixed. In the mean
- time, hack around it. */
-
- if (! (TEST_HARD_REG_BIT (elim_reg_set, regno_first)
- && (regno_first == FRAME_POINTER_REGNUM
- || regno_first == ARG_POINTER_REGNUM)))
- for (i = regno_first; i <= regno_last; ++i)
- regs_ever_live[i] = 1;
- }
- else
- {
- /* Keep track of which basic block each reg appears in. */
-
- int blocknum = pbi->bb->index;
- if (REG_BASIC_BLOCK (regno_first) == REG_BLOCK_UNKNOWN)
- REG_BASIC_BLOCK (regno_first) = blocknum;
- else if (REG_BASIC_BLOCK (regno_first) != blocknum)
- REG_BASIC_BLOCK (regno_first) = REG_BLOCK_GLOBAL;
-
- /* Count (weighted) number of uses of each reg. */
- REG_FREQ (regno_first) += REG_FREQ_FROM_BB (pbi->bb);
- REG_N_REFS (regno_first)++;
- }
- }
-
- /* Record and count the insns in which a reg dies. If it is used in
- this insn and was dead below the insn then it dies in this insn.
- If it was set in this insn, we do not make a REG_DEAD note;
- likewise if we already made such a note. */
- if ((pbi->flags & (PROP_DEATH_NOTES | PROP_REG_INFO))
- && some_was_dead
- && some_not_set)
- {
- /* Check for the case where the register dying partially
- overlaps the register set by this insn. */
- if (regno_first != regno_last)
- for (i = regno_first; i <= regno_last; ++i)
- some_was_live |= REGNO_REG_SET_P (pbi->new_set, i);
-
- /* If none of the words in X is needed, make a REG_DEAD note.
- Otherwise, we must make partial REG_DEAD notes. */
- if (! some_was_live)
- {
- if ((pbi->flags & PROP_DEATH_NOTES)
- && ! find_regno_note (insn, REG_DEAD, regno_first))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_DEAD, reg, REG_NOTES (insn));
-
- if (pbi->flags & PROP_REG_INFO)
- REG_N_DEATHS (regno_first)++;
- }
- else
- {
- /* Don't make a REG_DEAD note for a part of a register
- that is set in the insn. */
- for (i = regno_first; i <= regno_last; ++i)
- if (! REGNO_REG_SET_P (pbi->reg_live, i)
- && ! dead_or_set_regno_p (insn, i))
- REG_NOTES (insn)
- = alloc_EXPR_LIST (REG_DEAD,
- gen_rtx_REG (reg_raw_mode[i], i),
- REG_NOTES (insn));
- }
- }
-
- /* Mark the register as being live. */
- for (i = regno_first; i <= regno_last; ++i)
- {
-#ifdef HAVE_conditional_execution
- int this_was_live = REGNO_REG_SET_P (pbi->reg_live, i);
-#endif
-
- SET_REGNO_REG_SET (pbi->reg_live, i);
-
-#ifdef HAVE_conditional_execution
- /* If this is a conditional use, record that fact. If it is later
- conditionally set, we'll know to kill the register. */
- if (cond != NULL_RTX)
- {
- splay_tree_node node;
- struct reg_cond_life_info *rcli;
- rtx ncond;
-
- if (this_was_live)
- {
- node = splay_tree_lookup (pbi->reg_cond_dead, i);
- if (node == NULL)
- {
- /* The register was unconditionally live previously.
- No need to do anything. */
- }
- else
- {
- /* The register was conditionally live previously.
- Subtract the new life cond from the old death cond. */
- rcli = (struct reg_cond_life_info *) node->value;
- ncond = rcli->condition;
- ncond = and_reg_cond (ncond, not_reg_cond (cond), 1);
-
- /* If the register is now unconditionally live,
- remove the entry in the splay_tree. */
- if (ncond == const0_rtx)
- splay_tree_remove (pbi->reg_cond_dead, i);
- else
- {
- rcli->condition = ncond;
- SET_REGNO_REG_SET (pbi->reg_cond_reg,
- REGNO (XEXP (cond, 0)));
- }
- }
- }
- else
- {
- /* The register was not previously live at all. Record
- the condition under which it is still dead. */
- rcli = (struct reg_cond_life_info *) xmalloc (sizeof (*rcli));
- rcli->condition = not_reg_cond (cond);
- rcli->stores = const0_rtx;
- rcli->orig_condition = const0_rtx;
- splay_tree_insert (pbi->reg_cond_dead, i,
- (splay_tree_value) rcli);
-
- SET_REGNO_REG_SET (pbi->reg_cond_reg, REGNO (XEXP (cond, 0)));
- }
- }
- else if (this_was_live)
- {
- /* The register may have been conditionally live previously, but
- is now unconditionally live. Remove it from the conditionally
- dead list, so that a conditional set won't cause us to think
- it dead. */
- splay_tree_remove (pbi->reg_cond_dead, i);
- }
-#endif
- }
-}
-
-/* Scan expression X and store a 1-bit in NEW_LIVE for each reg it uses.
- This is done assuming the registers needed from X are those that
- have 1-bits in PBI->REG_LIVE.
-
- INSN is the containing instruction. If INSN is dead, this function
- is not called. */
-
-static void
-mark_used_regs (pbi, x, cond, insn)
- struct propagate_block_info *pbi;
- rtx x, cond, insn;
-{
- RTX_CODE code;
- int regno;
- int flags = pbi->flags;
-
- retry:
- if (!x)
- return;
- code = GET_CODE (x);
- switch (code)
- {
- case LABEL_REF:
- case SYMBOL_REF:
- case CONST_INT:
- case CONST:
- case CONST_DOUBLE:
- case CONST_VECTOR:
- case PC:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return;
-
-#ifdef HAVE_cc0
- case CC0:
- pbi->cc0_live = 1;
- return;
-#endif
-
- case CLOBBER:
- /* If we are clobbering a MEM, mark any registers inside the address
- as being used. */
- if (GET_CODE (XEXP (x, 0)) == MEM)
- mark_used_regs (pbi, XEXP (XEXP (x, 0), 0), cond, insn);
- return;
-
- case MEM:
- /* Don't bother watching stores to mems if this is not the
- final pass. We'll not be deleting dead stores this round. */
- if (optimize && (flags & PROP_SCAN_DEAD_CODE))
- {
- /* Invalidate the data for the last MEM stored, but only if MEM is
- something that can be stored into. */
- if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
- && CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
- /* Needn't clear the memory set list. */
- ;
- else
- {
- rtx temp = pbi->mem_set_list;
- rtx prev = NULL_RTX;
- rtx next;
-
- while (temp)
- {
- next = XEXP (temp, 1);
- if (anti_dependence (XEXP (temp, 0), x))
- {
- /* Splice temp out of the list. */
- if (prev)
- XEXP (prev, 1) = next;
- else
- pbi->mem_set_list = next;
- free_EXPR_LIST_node (temp);
- pbi->mem_set_list_len--;
- }
- else
- prev = temp;
- temp = next;
- }
- }
-
- /* If the memory reference had embedded side effects (autoincrement
- address modes. Then we may need to kill some entries on the
- memory set list. */
- if (insn)
- invalidate_mems_from_autoinc (pbi, insn);
- }
-
-#ifdef AUTO_INC_DEC
- if (flags & PROP_AUTOINC)
- find_auto_inc (pbi, x, insn);
-#endif
- break;
-
- case SUBREG:
-#ifdef CLASS_CANNOT_CHANGE_MODE
- if (GET_CODE (SUBREG_REG (x)) == REG
- && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER
- && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (x),
- GET_MODE (SUBREG_REG (x))))
- REG_CHANGES_MODE (REGNO (SUBREG_REG (x))) = 1;
-#endif
-
- /* While we're here, optimize this case. */
- x = SUBREG_REG (x);
- if (GET_CODE (x) != REG)
- goto retry;
- /* Fall through. */
-
- case REG:
- /* See a register other than being set => mark it as needed. */
- mark_used_reg (pbi, x, cond, insn);
- return;
-
- case SET:
- {
- rtx testreg = SET_DEST (x);
- int mark_dest = 0;
-
- /* If storing into MEM, don't show it as being used. But do
- show the address as being used. */
- if (GET_CODE (testreg) == MEM)
- {
-#ifdef AUTO_INC_DEC
- if (flags & PROP_AUTOINC)
- find_auto_inc (pbi, testreg, insn);
-#endif
- mark_used_regs (pbi, XEXP (testreg, 0), cond, insn);
- mark_used_regs (pbi, SET_SRC (x), cond, insn);
- return;
- }
-
- /* Storing in STRICT_LOW_PART is like storing in a reg
- in that this SET might be dead, so ignore it in TESTREG.
- but in some other ways it is like using the reg.
-
- Storing in a SUBREG or a bit field is like storing the entire
- register in that if the register's value is not used
- then this SET is not needed. */
- while (GET_CODE (testreg) == STRICT_LOW_PART
- || GET_CODE (testreg) == ZERO_EXTRACT
- || GET_CODE (testreg) == SIGN_EXTRACT
- || GET_CODE (testreg) == SUBREG)
- {
-#ifdef CLASS_CANNOT_CHANGE_MODE
- if (GET_CODE (testreg) == SUBREG
- && GET_CODE (SUBREG_REG (testreg)) == REG
- && REGNO (SUBREG_REG (testreg)) >= FIRST_PSEUDO_REGISTER
- && CLASS_CANNOT_CHANGE_MODE_P (GET_MODE (SUBREG_REG (testreg)),
- GET_MODE (testreg)))
- REG_CHANGES_MODE (REGNO (SUBREG_REG (testreg))) = 1;
-#endif
-
- /* Modifying a single register in an alternate mode
- does not use any of the old value. But these other
- ways of storing in a register do use the old value. */
- if (GET_CODE (testreg) == SUBREG
- && !((REG_BYTES (SUBREG_REG (testreg))
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD
- > (REG_BYTES (testreg)
- + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
- ;
- else
- mark_dest = 1;
-
- testreg = XEXP (testreg, 0);
- }
-
- /* If this is a store into a register or group of registers,
- recursively scan the value being stored. */
-
- if ((GET_CODE (testreg) == PARALLEL
- && GET_MODE (testreg) == BLKmode)
- || (GET_CODE (testreg) == REG
- && (regno = REGNO (testreg),
- ! (regno == FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed)))
-#if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
- && ! (regno == HARD_FRAME_POINTER_REGNUM
- && (! reload_completed || frame_pointer_needed))
-#endif
-#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
- && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno])
-#endif
- ))
- {
- if (mark_dest)
- mark_used_regs (pbi, SET_DEST (x), cond, insn);
- mark_used_regs (pbi, SET_SRC (x), cond, insn);
- return;
- }
- }
- break;
-
- case ASM_OPERANDS:
- case UNSPEC_VOLATILE:
- case TRAP_IF:
- case ASM_INPUT:
- {
- /* Traditional and volatile asm instructions must be considered to use
- and clobber all hard registers, all pseudo-registers and all of
- memory. So must TRAP_IF and UNSPEC_VOLATILE operations.
-
- Consider for instance a volatile asm that changes the fpu rounding
- mode. An insn should not be moved across this even if it only uses
- pseudo-regs because it might give an incorrectly rounded result.
-
- ?!? Unfortunately, marking all hard registers as live causes massive
- problems for the register allocator and marking all pseudos as live
- creates mountains of uninitialized variable warnings.
-
- So for now, just clear the memory set list and mark any regs
- we can find in ASM_OPERANDS as used. */
- if (code != ASM_OPERANDS || MEM_VOLATILE_P (x))
- {
- free_EXPR_LIST_list (&pbi->mem_set_list);
- pbi->mem_set_list_len = 0;
- }
-
- /* For all ASM_OPERANDS, we must traverse the vector of input operands.
- We can not just fall through here since then we would be confused
- by the ASM_INPUT rtx inside ASM_OPERANDS, which do not indicate
- traditional asms unlike their normal usage. */
- if (code == ASM_OPERANDS)
- {
- int j;
-
- for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
- mark_used_regs (pbi, ASM_OPERANDS_INPUT (x, j), cond, insn);
- }
- break;
- }
-
- case COND_EXEC:
- if (cond != NULL_RTX)
- abort ();
-
- mark_used_regs (pbi, COND_EXEC_TEST (x), NULL_RTX, insn);
-
- cond = COND_EXEC_TEST (x);
- x = COND_EXEC_CODE (x);
- goto retry;
-
- case PHI:
- /* We _do_not_ want to scan operands of phi nodes. Operands of
- a phi function are evaluated only when control reaches this
- block along a particular edge. Therefore, regs that appear
- as arguments to phi should not be added to the global live at
- start. */
- return;
-
- default:
- break;
- }
-
- /* Recursively scan the operands of this expression. */
-
- {
- const char * const fmt = GET_RTX_FORMAT (code);
- int i;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* Tail recursive case: save a function call level. */
- if (i == 0)
- {
- x = XEXP (x, 0);
- goto retry;
- }
- mark_used_regs (pbi, XEXP (x, i), cond, insn);
- }
- else if (fmt[i] == 'E')
- {
- int j;
- for (j = 0; j < XVECLEN (x, i); j++)
- mark_used_regs (pbi, XVECEXP (x, i, j), cond, insn);
- }
- }
- }
-}
-\f
-#ifdef AUTO_INC_DEC
-
-static int
-try_pre_increment_1 (pbi, insn)
- struct propagate_block_info *pbi;
- rtx insn;
-{
- /* Find the next use of this reg. If in same basic block,
- make it do pre-increment or pre-decrement if appropriate. */
- rtx x = single_set (insn);
- HOST_WIDE_INT amount = ((GET_CODE (SET_SRC (x)) == PLUS ? 1 : -1)
- * INTVAL (XEXP (SET_SRC (x), 1)));
- int regno = REGNO (SET_DEST (x));
- rtx y = pbi->reg_next_use[regno];
- if (y != 0
- && SET_DEST (x) != stack_pointer_rtx
- && BLOCK_NUM (y) == BLOCK_NUM (insn)
- /* Don't do this if the reg dies, or gets set in y; a standard addressing
- mode would be better. */
- && ! dead_or_set_p (y, SET_DEST (x))
- && try_pre_increment (y, SET_DEST (x), amount))
- {
- /* We have found a suitable auto-increment and already changed
- insn Y to do it. So flush this increment instruction. */
- propagate_block_delete_insn (pbi->bb, insn);
-
- /* Count a reference to this reg for the increment insn we are
- deleting. When a reg is incremented, spilling it is worse,
- so we want to make that less likely. */
- if (regno >= FIRST_PSEUDO_REGISTER)
- {
- REG_FREQ (regno) += REG_FREQ_FROM_BB (pbi->bb);
- REG_N_SETS (regno)++;
- }
-
- /* Flush any remembered memories depending on the value of
- the incremented register. */
- invalidate_mems_from_set (pbi, SET_DEST (x));
-
- return 1;
- }
- return 0;
-}
-
-/* Try to change INSN so that it does pre-increment or pre-decrement
- addressing on register REG in order to add AMOUNT to REG.
- AMOUNT is negative for pre-decrement.
- Returns 1 if the change could be made.
- This checks all about the validity of the result of modifying INSN. */
-
-static int
-try_pre_increment (insn, reg, amount)
- rtx insn, reg;
- HOST_WIDE_INT amount;
-{
- rtx use;
-
- /* Nonzero if we can try to make a pre-increment or pre-decrement.
- For example, addl $4,r1; movl (r1),... can become movl +(r1),... */
- int pre_ok = 0;
- /* Nonzero if we can try to make a post-increment or post-decrement.
- For example, addl $4,r1; movl -4(r1),... can become movl (r1)+,...
- It is possible for both PRE_OK and POST_OK to be nonzero if the machine
- supports both pre-inc and post-inc, or both pre-dec and post-dec. */
- int post_ok = 0;
-
- /* Nonzero if the opportunity actually requires post-inc or post-dec. */
- int do_post = 0;
-
- /* From the sign of increment, see which possibilities are conceivable
- on this target machine. */
- if (HAVE_PRE_INCREMENT && amount > 0)
- pre_ok = 1;
- if (HAVE_POST_INCREMENT && amount > 0)
- post_ok = 1;
-
- if (HAVE_PRE_DECREMENT && amount < 0)
- pre_ok = 1;
- if (HAVE_POST_DECREMENT && amount < 0)
- post_ok = 1;
-
- if (! (pre_ok || post_ok))
- return 0;
-
- /* It is not safe to add a side effect to a jump insn
- because if the incremented register is spilled and must be reloaded
- there would be no way to store the incremented value back in memory. */
-
- if (GET_CODE (insn) == JUMP_INSN)
- return 0;
-
- use = 0;
- if (pre_ok)
- use = find_use_as_address (PATTERN (insn), reg, 0);
- if (post_ok && (use == 0 || use == (rtx) (size_t) 1))
- {
- use = find_use_as_address (PATTERN (insn), reg, -amount);
- do_post = 1;
- }
-
- if (use == 0 || use == (rtx) (size_t) 1)
- return 0;
-
- if (GET_MODE_SIZE (GET_MODE (use)) != (amount > 0 ? amount : - amount))
- return 0;
-
- /* See if this combination of instruction and addressing mode exists. */
- if (! validate_change (insn, &XEXP (use, 0),
- gen_rtx_fmt_e (amount > 0
- ? (do_post ? POST_INC : PRE_INC)
- : (do_post ? POST_DEC : PRE_DEC),
- Pmode, reg), 0))
- return 0;
-
- /* Record that this insn now has an implicit side effect on X. */
- REG_NOTES (insn) = alloc_EXPR_LIST (REG_INC, reg, REG_NOTES (insn));
- return 1;
-}
-
-#endif /* AUTO_INC_DEC */
-\f
-/* Find the place in the rtx X where REG is used as a memory address.
- Return the MEM rtx that so uses it.
- If PLUSCONST is nonzero, search instead for a memory address equivalent to
- (plus REG (const_int PLUSCONST)).
-
- If such an address does not appear, return 0.
- If REG appears more than once, or is used other than in such an address,
- return (rtx) 1. */
-
-rtx
-find_use_as_address (x, reg, plusconst)
- rtx x;
- rtx reg;
- HOST_WIDE_INT plusconst;
-{
- enum rtx_code code = GET_CODE (x);
- const char * const fmt = GET_RTX_FORMAT (code);
- int i;
- rtx value = 0;
- rtx tem;
-
- if (code == MEM && XEXP (x, 0) == reg && plusconst == 0)
- return x;
-
- if (code == MEM && GET_CODE (XEXP (x, 0)) == PLUS
- && XEXP (XEXP (x, 0), 0) == reg
- && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
- && INTVAL (XEXP (XEXP (x, 0), 1)) == plusconst)
- return x;
-
- if (code == SIGN_EXTRACT || code == ZERO_EXTRACT)
- {
- /* If REG occurs inside a MEM used in a bit-field reference,
- that is unacceptable. */
- if (find_use_as_address (XEXP (x, 0), reg, 0) != 0)
- return (rtx) (size_t) 1;
- }
-
- if (x == reg)
- return (rtx) (size_t) 1;
-
- for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- tem = find_use_as_address (XEXP (x, i), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (size_t) 1;
- }
- else if (fmt[i] == 'E')
- {
- int j;
- for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- {
- tem = find_use_as_address (XVECEXP (x, i, j), reg, plusconst);
- if (value == 0)
- value = tem;
- else if (tem != 0)
- return (rtx) (size_t) 1;
- }
- }
- }
-
- return value;
-}
-\f
-/* Write information about registers and basic blocks into FILE.
- This is part of making a debugging dump. */
-
-void
-dump_regset (r, outf)
- regset r;
- FILE *outf;
-{
- int i;
- if (r == NULL)
- {
- fputs (" (nil)", outf);
- return;
- }
-
- EXECUTE_IF_SET_IN_REG_SET (r, 0, i,
- {
- fprintf (outf, " %d", i);
- if (i < FIRST_PSEUDO_REGISTER)
- fprintf (outf, " [%s]",
- reg_names[i]);
- });
-}
-
-/* Print a human-reaable representation of R on the standard error
- stream. This function is designed to be used from within the
- debugger. */
-
-void
-debug_regset (r)
- regset r;
-{
- dump_regset (r, stderr);
- putc ('\n', stderr);
-}
-
-/* Recompute register set/reference counts immediately prior to register
- allocation.
-
- This avoids problems with set/reference counts changing to/from values
- which have special meanings to the register allocators.
-
- Additionally, the reference counts are the primary component used by the
- register allocators to prioritize pseudos for allocation to hard regs.
- More accurate reference counts generally lead to better register allocation.
-
- F is the first insn to be scanned.
-
- LOOP_STEP denotes how much loop_depth should be incremented per
- loop nesting level in order to increase the ref count more for
- references in a loop.
-
- It might be worthwhile to update REG_LIVE_LENGTH, REG_BASIC_BLOCK and
- possibly other information which is used by the register allocators. */
-
-void
-recompute_reg_usage (f, loop_step)
- rtx f ATTRIBUTE_UNUSED;
- int loop_step ATTRIBUTE_UNUSED;
-{
- allocate_reg_life_data ();
- update_life_info (NULL, UPDATE_LIFE_LOCAL, PROP_REG_INFO);
-}
-
-/* Optionally removes all the REG_DEAD and REG_UNUSED notes from a set of
- blocks. If BLOCKS is NULL, assume the universal set. Returns a count
- of the number of registers that died. */
-
-int
-count_or_remove_death_notes (blocks, kill)
- sbitmap blocks;
- int kill;
-{
- int i, count = 0;
-
- for (i = n_basic_blocks - 1; i >= 0; --i)
- {
- basic_block bb;
- rtx insn;
-
- if (blocks && ! TEST_BIT (blocks, i))
- continue;
-
- bb = BASIC_BLOCK (i);
-
- for (insn = bb->head;; insn = NEXT_INSN (insn))
- {
- if (INSN_P (insn))
- {
- rtx *pprev = ®_NOTES (insn);
- rtx link = *pprev;
-
- while (link)
- {
- switch (REG_NOTE_KIND (link))
- {
- case REG_DEAD:
- if (GET_CODE (XEXP (link, 0)) == REG)
- {
- rtx reg = XEXP (link, 0);
- int n;
-
- if (REGNO (reg) >= FIRST_PSEUDO_REGISTER)
- n = 1;
- else
- n = HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg));
- count += n;
- }
- /* Fall through. */
-
- case REG_UNUSED:
- if (kill)
- {
- rtx next = XEXP (link, 1);
- free_EXPR_LIST_node (link);
- *pprev = link = next;
- break;
- }
- /* Fall through. */
-
- default:
- pprev = &XEXP (link, 1);
- link = *pprev;
- break;
- }
- }
- }
-
- if (insn == bb->end)
- break;
- }
- }
-
- return count;
-}
-/* Clear LOG_LINKS fields of insns in a selected blocks or whole chain
- if blocks is NULL. */
-
-static void
-clear_log_links (blocks)
- sbitmap blocks;
-{
- rtx insn;
- int i;
-
- if (!blocks)
- {
- for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- free_INSN_LIST_list (&LOG_LINKS (insn));
- }
- else
- EXECUTE_IF_SET_IN_SBITMAP (blocks, 0, i,
- {
- basic_block bb = BASIC_BLOCK (i);
-
- for (insn = bb->head; insn != NEXT_INSN (bb->end);
- insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- free_INSN_LIST_list (&LOG_LINKS (insn));
- });
-}
-
-/* Given a register bitmap, turn on the bits in a HARD_REG_SET that
- correspond to the hard registers, if any, set in that map. This
- could be done far more efficiently by having all sorts of special-cases
- with moving single words, but probably isn't worth the trouble. */
-
-void
-reg_set_to_hard_reg_set (to, from)
- HARD_REG_SET *to;
- bitmap from;
-{
- int i;
-
- EXECUTE_IF_SET_IN_BITMAP
- (from, 0, i,
- {
- if (i >= FIRST_PSEUDO_REGISTER)
- return;
- SET_HARD_REG_BIT (*to, i);
- });
-}
projects / msp430-gcc.git / blobdiff