X-Git-Url: https://oss.titaniummirror.com/gitweb/?a=blobdiff_plain;f=gcc%2Ftree-ssa-loop-ivopts.c;fp=gcc%2Ftree-ssa-loop-ivopts.c;h=fcaf7846458b43841988abc9c0eee1cd16f62fdb;hb=6fed43773c9b0ce596dca5686f37ac3fc0fa11c0;hp=0000000000000000000000000000000000000000;hpb=27b11d56b743098deb193d510b337ba22dc52e5c;p=msp430-gcc.git diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c new file mode 100644 index 00000000..fcaf7846 --- /dev/null +++ b/gcc/tree-ssa-loop-ivopts.c @@ -0,0 +1,5613 @@ +/* Induction variable optimizations. + Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 + 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 3, 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 COPYING3. If not see +. */ + +/* This pass tries to find the optimal set of induction variables for the loop. + It optimizes just the basic linear induction variables (although adding + support for other types should not be too hard). It includes the + optimizations commonly known as strength reduction, induction variable + coalescing and induction variable elimination. It does it in the + following steps: + + 1) The interesting uses of induction variables are found. This includes + + -- uses of induction variables in non-linear expressions + -- addresses of arrays + -- comparisons of induction variables + + 2) Candidates for the induction variables are found. This includes + + -- old induction variables + -- the variables defined by expressions derived from the "interesting + uses" above + + 3) The optimal (w.r. to a cost function) set of variables is chosen. The + cost function assigns a cost to sets of induction variables and consists + of three parts: + + -- The use costs. Each of the interesting uses chooses the best induction + variable in the set and adds its cost to the sum. The cost reflects + the time spent on modifying the induction variables value to be usable + for the given purpose (adding base and offset for arrays, etc.). + -- The variable costs. Each of the variables has a cost assigned that + reflects the costs associated with incrementing the value of the + variable. The original variables are somewhat preferred. + -- The set cost. Depending on the size of the set, extra cost may be + added to reflect register pressure. + + All the costs are defined in a machine-specific way, using the target + hooks and machine descriptions to determine them. + + 4) The trees are transformed to use the new variables, the dead code is + removed. + + All of this is done loop by loop. Doing it globally is theoretically + possible, it might give a better performance and it might enable us + to decide costs more precisely, but getting all the interactions right + would be complicated. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "tree.h" +#include "rtl.h" +#include "tm_p.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "output.h" +#include "diagnostic.h" +#include "tree-flow.h" +#include "tree-dump.h" +#include "timevar.h" +#include "cfgloop.h" +#include "varray.h" +#include "expr.h" +#include "tree-pass.h" +#include "ggc.h" +#include "insn-config.h" +#include "recog.h" +#include "pointer-set.h" +#include "hashtab.h" +#include "tree-chrec.h" +#include "tree-scalar-evolution.h" +#include "cfgloop.h" +#include "params.h" +#include "langhooks.h" +#include "tree-affine.h" +#include "target.h" + +/* The infinite cost. */ +#define INFTY 10000000 + +/* The expected number of loop iterations. TODO -- use profiling instead of + this. */ +#define AVG_LOOP_NITER(LOOP) 5 + + +/* Representation of the induction variable. */ +struct iv +{ + tree base; /* Initial value of the iv. */ + tree base_object; /* A memory object to that the induction variable points. */ + tree step; /* Step of the iv (constant only). */ + tree ssa_name; /* The ssa name with the value. */ + bool biv_p; /* Is it a biv? */ + bool have_use_for; /* Do we already have a use for it? */ + unsigned use_id; /* The identifier in the use if it is the case. */ +}; + +/* Per-ssa version information (induction variable descriptions, etc.). */ +struct version_info +{ + tree name; /* The ssa name. */ + struct iv *iv; /* Induction variable description. */ + bool has_nonlin_use; /* For a loop-level invariant, whether it is used in + an expression that is not an induction variable. */ + unsigned inv_id; /* Id of an invariant. */ + bool preserve_biv; /* For the original biv, whether to preserve it. */ +}; + +/* Types of uses. */ +enum use_type +{ + USE_NONLINEAR_EXPR, /* Use in a nonlinear expression. */ + USE_ADDRESS, /* Use in an address. */ + USE_COMPARE /* Use is a compare. */ +}; + +/* Cost of a computation. */ +typedef struct +{ + unsigned cost; /* The runtime cost. */ + unsigned complexity; /* The estimate of the complexity of the code for + the computation (in no concrete units -- + complexity field should be larger for more + complex expressions and addressing modes). */ +} comp_cost; + +static const comp_cost zero_cost = {0, 0}; +static const comp_cost infinite_cost = {INFTY, INFTY}; + +/* The candidate - cost pair. */ +struct cost_pair +{ + struct iv_cand *cand; /* The candidate. */ + comp_cost cost; /* The cost. */ + bitmap depends_on; /* The list of invariants that have to be + preserved. */ + tree value; /* For final value elimination, the expression for + the final value of the iv. For iv elimination, + the new bound to compare with. */ +}; + +/* Use. */ +struct iv_use +{ + unsigned id; /* The id of the use. */ + enum use_type type; /* Type of the use. */ + struct iv *iv; /* The induction variable it is based on. */ + gimple stmt; /* Statement in that it occurs. */ + tree *op_p; /* The place where it occurs. */ + bitmap related_cands; /* The set of "related" iv candidates, plus the common + important ones. */ + + unsigned n_map_members; /* Number of candidates in the cost_map list. */ + struct cost_pair *cost_map; + /* The costs wrto the iv candidates. */ + + struct iv_cand *selected; + /* The selected candidate. */ +}; + +/* The position where the iv is computed. */ +enum iv_position +{ + IP_NORMAL, /* At the end, just before the exit condition. */ + IP_END, /* At the end of the latch block. */ + IP_ORIGINAL /* The original biv. */ +}; + +/* The induction variable candidate. */ +struct iv_cand +{ + unsigned id; /* The number of the candidate. */ + bool important; /* Whether this is an "important" candidate, i.e. such + that it should be considered by all uses. */ + enum iv_position pos; /* Where it is computed. */ + gimple incremented_at;/* For original biv, the statement where it is + incremented. */ + tree var_before; /* The variable used for it before increment. */ + tree var_after; /* The variable used for it after increment. */ + struct iv *iv; /* The value of the candidate. NULL for + "pseudocandidate" used to indicate the possibility + to replace the final value of an iv by direct + computation of the value. */ + unsigned cost; /* Cost of the candidate. */ + bitmap depends_on; /* The list of invariants that are used in step of the + biv. */ +}; + +/* The data used by the induction variable optimizations. */ + +typedef struct iv_use *iv_use_p; +DEF_VEC_P(iv_use_p); +DEF_VEC_ALLOC_P(iv_use_p,heap); + +typedef struct iv_cand *iv_cand_p; +DEF_VEC_P(iv_cand_p); +DEF_VEC_ALLOC_P(iv_cand_p,heap); + +struct ivopts_data +{ + /* The currently optimized loop. */ + struct loop *current_loop; + + /* Numbers of iterations for all exits of the current loop. */ + struct pointer_map_t *niters; + + /* Number of registers used in it. */ + unsigned regs_used; + + /* The size of version_info array allocated. */ + unsigned version_info_size; + + /* The array of information for the ssa names. */ + struct version_info *version_info; + + /* The bitmap of indices in version_info whose value was changed. */ + bitmap relevant; + + /* The uses of induction variables. */ + VEC(iv_use_p,heap) *iv_uses; + + /* The candidates. */ + VEC(iv_cand_p,heap) *iv_candidates; + + /* A bitmap of important candidates. */ + bitmap important_candidates; + + /* The maximum invariant id. */ + unsigned max_inv_id; + + /* Whether to consider just related and important candidates when replacing a + use. */ + bool consider_all_candidates; + + /* Are we optimizing for speed? */ + bool speed; +}; + +/* An assignment of iv candidates to uses. */ + +struct iv_ca +{ + /* The number of uses covered by the assignment. */ + unsigned upto; + + /* Number of uses that cannot be expressed by the candidates in the set. */ + unsigned bad_uses; + + /* Candidate assigned to a use, together with the related costs. */ + struct cost_pair **cand_for_use; + + /* Number of times each candidate is used. */ + unsigned *n_cand_uses; + + /* The candidates used. */ + bitmap cands; + + /* The number of candidates in the set. */ + unsigned n_cands; + + /* Total number of registers needed. */ + unsigned n_regs; + + /* Total cost of expressing uses. */ + comp_cost cand_use_cost; + + /* Total cost of candidates. */ + unsigned cand_cost; + + /* Number of times each invariant is used. */ + unsigned *n_invariant_uses; + + /* Total cost of the assignment. */ + comp_cost cost; +}; + +/* Difference of two iv candidate assignments. */ + +struct iv_ca_delta +{ + /* Changed use. */ + struct iv_use *use; + + /* An old assignment (for rollback purposes). */ + struct cost_pair *old_cp; + + /* A new assignment. */ + struct cost_pair *new_cp; + + /* Next change in the list. */ + struct iv_ca_delta *next_change; +}; + +/* Bound on number of candidates below that all candidates are considered. */ + +#define CONSIDER_ALL_CANDIDATES_BOUND \ + ((unsigned) PARAM_VALUE (PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND)) + +/* If there are more iv occurrences, we just give up (it is quite unlikely that + optimizing such a loop would help, and it would take ages). */ + +#define MAX_CONSIDERED_USES \ + ((unsigned) PARAM_VALUE (PARAM_IV_MAX_CONSIDERED_USES)) + +/* If there are at most this number of ivs in the set, try removing unnecessary + ivs from the set always. */ + +#define ALWAYS_PRUNE_CAND_SET_BOUND \ + ((unsigned) PARAM_VALUE (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND)) + +/* The list of trees for that the decl_rtl field must be reset is stored + here. */ + +static VEC(tree,heap) *decl_rtl_to_reset; + +/* Number of uses recorded in DATA. */ + +static inline unsigned +n_iv_uses (struct ivopts_data *data) +{ + return VEC_length (iv_use_p, data->iv_uses); +} + +/* Ith use recorded in DATA. */ + +static inline struct iv_use * +iv_use (struct ivopts_data *data, unsigned i) +{ + return VEC_index (iv_use_p, data->iv_uses, i); +} + +/* Number of candidates recorded in DATA. */ + +static inline unsigned +n_iv_cands (struct ivopts_data *data) +{ + return VEC_length (iv_cand_p, data->iv_candidates); +} + +/* Ith candidate recorded in DATA. */ + +static inline struct iv_cand * +iv_cand (struct ivopts_data *data, unsigned i) +{ + return VEC_index (iv_cand_p, data->iv_candidates, i); +} + +/* The single loop exit if it dominates the latch, NULL otherwise. */ + +edge +single_dom_exit (struct loop *loop) +{ + edge exit = single_exit (loop); + + if (!exit) + return NULL; + + if (!just_once_each_iteration_p (loop, exit->src)) + return NULL; + + return exit; +} + +/* Dumps information about the induction variable IV to FILE. */ + +extern void dump_iv (FILE *, struct iv *); +void +dump_iv (FILE *file, struct iv *iv) +{ + if (iv->ssa_name) + { + fprintf (file, "ssa name "); + print_generic_expr (file, iv->ssa_name, TDF_SLIM); + fprintf (file, "\n"); + } + + fprintf (file, " type "); + print_generic_expr (file, TREE_TYPE (iv->base), TDF_SLIM); + fprintf (file, "\n"); + + if (iv->step) + { + fprintf (file, " base "); + print_generic_expr (file, iv->base, TDF_SLIM); + fprintf (file, "\n"); + + fprintf (file, " step "); + print_generic_expr (file, iv->step, TDF_SLIM); + fprintf (file, "\n"); + } + else + { + fprintf (file, " invariant "); + print_generic_expr (file, iv->base, TDF_SLIM); + fprintf (file, "\n"); + } + + if (iv->base_object) + { + fprintf (file, " base object "); + print_generic_expr (file, iv->base_object, TDF_SLIM); + fprintf (file, "\n"); + } + + if (iv->biv_p) + fprintf (file, " is a biv\n"); +} + +/* Dumps information about the USE to FILE. */ + +extern void dump_use (FILE *, struct iv_use *); +void +dump_use (FILE *file, struct iv_use *use) +{ + fprintf (file, "use %d\n", use->id); + + switch (use->type) + { + case USE_NONLINEAR_EXPR: + fprintf (file, " generic\n"); + break; + + case USE_ADDRESS: + fprintf (file, " address\n"); + break; + + case USE_COMPARE: + fprintf (file, " compare\n"); + break; + + default: + gcc_unreachable (); + } + + fprintf (file, " in statement "); + print_gimple_stmt (file, use->stmt, 0, 0); + fprintf (file, "\n"); + + fprintf (file, " at position "); + if (use->op_p) + print_generic_expr (file, *use->op_p, TDF_SLIM); + fprintf (file, "\n"); + + dump_iv (file, use->iv); + + if (use->related_cands) + { + fprintf (file, " related candidates "); + dump_bitmap (file, use->related_cands); + } +} + +/* Dumps information about the uses to FILE. */ + +extern void dump_uses (FILE *, struct ivopts_data *); +void +dump_uses (FILE *file, struct ivopts_data *data) +{ + unsigned i; + struct iv_use *use; + + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + + dump_use (file, use); + fprintf (file, "\n"); + } +} + +/* Dumps information about induction variable candidate CAND to FILE. */ + +extern void dump_cand (FILE *, struct iv_cand *); +void +dump_cand (FILE *file, struct iv_cand *cand) +{ + struct iv *iv = cand->iv; + + fprintf (file, "candidate %d%s\n", + cand->id, cand->important ? " (important)" : ""); + + if (cand->depends_on) + { + fprintf (file, " depends on "); + dump_bitmap (file, cand->depends_on); + } + + if (!iv) + { + fprintf (file, " final value replacement\n"); + return; + } + + switch (cand->pos) + { + case IP_NORMAL: + fprintf (file, " incremented before exit test\n"); + break; + + case IP_END: + fprintf (file, " incremented at end\n"); + break; + + case IP_ORIGINAL: + fprintf (file, " original biv\n"); + break; + } + + dump_iv (file, iv); +} + +/* Returns the info for ssa version VER. */ + +static inline struct version_info * +ver_info (struct ivopts_data *data, unsigned ver) +{ + return data->version_info + ver; +} + +/* Returns the info for ssa name NAME. */ + +static inline struct version_info * +name_info (struct ivopts_data *data, tree name) +{ + return ver_info (data, SSA_NAME_VERSION (name)); +} + +/* Returns true if STMT is after the place where the IP_NORMAL ivs will be + emitted in LOOP. */ + +static bool +stmt_after_ip_normal_pos (struct loop *loop, gimple stmt) +{ + basic_block bb = ip_normal_pos (loop), sbb = gimple_bb (stmt); + + gcc_assert (bb); + + if (sbb == loop->latch) + return true; + + if (sbb != bb) + return false; + + return stmt == last_stmt (bb); +} + +/* Returns true if STMT if after the place where the original induction + variable CAND is incremented. */ + +static bool +stmt_after_ip_original_pos (struct iv_cand *cand, gimple stmt) +{ + basic_block cand_bb = gimple_bb (cand->incremented_at); + basic_block stmt_bb = gimple_bb (stmt); + gimple_stmt_iterator bsi; + + if (!dominated_by_p (CDI_DOMINATORS, stmt_bb, cand_bb)) + return false; + + if (stmt_bb != cand_bb) + return true; + + /* Scan the block from the end, since the original ivs are usually + incremented at the end of the loop body. */ + for (bsi = gsi_last_bb (stmt_bb); ; gsi_prev (&bsi)) + { + if (gsi_stmt (bsi) == cand->incremented_at) + return false; + if (gsi_stmt (bsi) == stmt) + return true; + } +} + +/* Returns true if STMT if after the place where the induction variable + CAND is incremented in LOOP. */ + +static bool +stmt_after_increment (struct loop *loop, struct iv_cand *cand, gimple stmt) +{ + switch (cand->pos) + { + case IP_END: + return false; + + case IP_NORMAL: + return stmt_after_ip_normal_pos (loop, stmt); + + case IP_ORIGINAL: + return stmt_after_ip_original_pos (cand, stmt); + + default: + gcc_unreachable (); + } +} + +/* Returns true if EXP is a ssa name that occurs in an abnormal phi node. */ + +static bool +abnormal_ssa_name_p (tree exp) +{ + if (!exp) + return false; + + if (TREE_CODE (exp) != SSA_NAME) + return false; + + return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (exp) != 0; +} + +/* Returns false if BASE or INDEX contains a ssa name that occurs in an + abnormal phi node. Callback for for_each_index. */ + +static bool +idx_contains_abnormal_ssa_name_p (tree base, tree *index, + void *data ATTRIBUTE_UNUSED) +{ + if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF) + { + if (abnormal_ssa_name_p (TREE_OPERAND (base, 2))) + return false; + if (abnormal_ssa_name_p (TREE_OPERAND (base, 3))) + return false; + } + + return !abnormal_ssa_name_p (*index); +} + +/* Returns true if EXPR contains a ssa name that occurs in an + abnormal phi node. */ + +bool +contains_abnormal_ssa_name_p (tree expr) +{ + enum tree_code code; + enum tree_code_class codeclass; + + if (!expr) + return false; + + code = TREE_CODE (expr); + codeclass = TREE_CODE_CLASS (code); + + if (code == SSA_NAME) + return SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr) != 0; + + if (code == INTEGER_CST + || is_gimple_min_invariant (expr)) + return false; + + if (code == ADDR_EXPR) + return !for_each_index (&TREE_OPERAND (expr, 0), + idx_contains_abnormal_ssa_name_p, + NULL); + + switch (codeclass) + { + case tcc_binary: + case tcc_comparison: + if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 1))) + return true; + + /* Fallthru. */ + case tcc_unary: + if (contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 0))) + return true; + + break; + + default: + gcc_unreachable (); + } + + return false; +} + +/* Returns tree describing number of iterations determined from + EXIT of DATA->current_loop, or NULL if something goes wrong. */ + +static tree +niter_for_exit (struct ivopts_data *data, edge exit) +{ + struct tree_niter_desc desc; + tree niter; + void **slot; + + if (!data->niters) + { + data->niters = pointer_map_create (); + slot = NULL; + } + else + slot = pointer_map_contains (data->niters, exit); + + if (!slot) + { + /* Try to determine number of iterations. We must know it + unconditionally (i.e., without possibility of # of iterations + being zero). Also, we cannot safely work with ssa names that + appear in phi nodes on abnormal edges, so that we do not create + overlapping life ranges for them (PR 27283). */ + if (number_of_iterations_exit (data->current_loop, + exit, &desc, true) + && integer_zerop (desc.may_be_zero) + && !contains_abnormal_ssa_name_p (desc.niter)) + niter = desc.niter; + else + niter = NULL_TREE; + + *pointer_map_insert (data->niters, exit) = niter; + } + else + niter = (tree) *slot; + + return niter; +} + +/* Returns tree describing number of iterations determined from + single dominating exit of DATA->current_loop, or NULL if something + goes wrong. */ + +static tree +niter_for_single_dom_exit (struct ivopts_data *data) +{ + edge exit = single_dom_exit (data->current_loop); + + if (!exit) + return NULL; + + return niter_for_exit (data, exit); +} + +/* Initializes data structures used by the iv optimization pass, stored + in DATA. */ + +static void +tree_ssa_iv_optimize_init (struct ivopts_data *data) +{ + data->version_info_size = 2 * num_ssa_names; + data->version_info = XCNEWVEC (struct version_info, data->version_info_size); + data->relevant = BITMAP_ALLOC (NULL); + data->important_candidates = BITMAP_ALLOC (NULL); + data->max_inv_id = 0; + data->niters = NULL; + data->iv_uses = VEC_alloc (iv_use_p, heap, 20); + data->iv_candidates = VEC_alloc (iv_cand_p, heap, 20); + decl_rtl_to_reset = VEC_alloc (tree, heap, 20); +} + +/* Returns a memory object to that EXPR points. In case we are able to + determine that it does not point to any such object, NULL is returned. */ + +static tree +determine_base_object (tree expr) +{ + enum tree_code code = TREE_CODE (expr); + tree base, obj; + + /* If this is a pointer casted to any type, we need to determine + the base object for the pointer; so handle conversions before + throwing away non-pointer expressions. */ + if (CONVERT_EXPR_P (expr)) + return determine_base_object (TREE_OPERAND (expr, 0)); + + if (!POINTER_TYPE_P (TREE_TYPE (expr))) + return NULL_TREE; + + switch (code) + { + case INTEGER_CST: + return NULL_TREE; + + case ADDR_EXPR: + obj = TREE_OPERAND (expr, 0); + base = get_base_address (obj); + + if (!base) + return expr; + + if (TREE_CODE (base) == INDIRECT_REF) + return determine_base_object (TREE_OPERAND (base, 0)); + + return fold_convert (ptr_type_node, + build_fold_addr_expr (base)); + + case POINTER_PLUS_EXPR: + return determine_base_object (TREE_OPERAND (expr, 0)); + + case PLUS_EXPR: + case MINUS_EXPR: + /* Pointer addition is done solely using POINTER_PLUS_EXPR. */ + gcc_unreachable (); + + default: + return fold_convert (ptr_type_node, expr); + } +} + +/* Allocates an induction variable with given initial value BASE and step STEP + for loop LOOP. */ + +static struct iv * +alloc_iv (tree base, tree step) +{ + struct iv *iv = XCNEW (struct iv); + gcc_assert (step != NULL_TREE); + + iv->base = base; + iv->base_object = determine_base_object (base); + iv->step = step; + iv->biv_p = false; + iv->have_use_for = false; + iv->use_id = 0; + iv->ssa_name = NULL_TREE; + + return iv; +} + +/* Sets STEP and BASE for induction variable IV. */ + +static void +set_iv (struct ivopts_data *data, tree iv, tree base, tree step) +{ + struct version_info *info = name_info (data, iv); + + gcc_assert (!info->iv); + + bitmap_set_bit (data->relevant, SSA_NAME_VERSION (iv)); + info->iv = alloc_iv (base, step); + info->iv->ssa_name = iv; +} + +/* Finds induction variable declaration for VAR. */ + +static struct iv * +get_iv (struct ivopts_data *data, tree var) +{ + basic_block bb; + tree type = TREE_TYPE (var); + + if (!POINTER_TYPE_P (type) + && !INTEGRAL_TYPE_P (type)) + return NULL; + + if (!name_info (data, var)->iv) + { + bb = gimple_bb (SSA_NAME_DEF_STMT (var)); + + if (!bb + || !flow_bb_inside_loop_p (data->current_loop, bb)) + set_iv (data, var, var, build_int_cst (type, 0)); + } + + return name_info (data, var)->iv; +} + +/* Determines the step of a biv defined in PHI. Returns NULL if PHI does + not define a simple affine biv with nonzero step. */ + +static tree +determine_biv_step (gimple phi) +{ + struct loop *loop = gimple_bb (phi)->loop_father; + tree name = PHI_RESULT (phi); + affine_iv iv; + + if (!is_gimple_reg (name)) + return NULL_TREE; + + if (!simple_iv (loop, loop, name, &iv, true)) + return NULL_TREE; + + return integer_zerop (iv.step) ? NULL_TREE : iv.step; +} + +/* Finds basic ivs. */ + +static bool +find_bivs (struct ivopts_data *data) +{ + gimple phi; + tree step, type, base; + bool found = false; + struct loop *loop = data->current_loop; + gimple_stmt_iterator psi; + + for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) + { + phi = gsi_stmt (psi); + + if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi))) + continue; + + step = determine_biv_step (phi); + if (!step) + continue; + + base = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop)); + base = expand_simple_operations (base); + if (contains_abnormal_ssa_name_p (base) + || contains_abnormal_ssa_name_p (step)) + continue; + + type = TREE_TYPE (PHI_RESULT (phi)); + base = fold_convert (type, base); + if (step) + { + if (POINTER_TYPE_P (type)) + step = fold_convert (sizetype, step); + else + step = fold_convert (type, step); + } + + set_iv (data, PHI_RESULT (phi), base, step); + found = true; + } + + return found; +} + +/* Marks basic ivs. */ + +static void +mark_bivs (struct ivopts_data *data) +{ + gimple phi; + tree var; + struct iv *iv, *incr_iv; + struct loop *loop = data->current_loop; + basic_block incr_bb; + gimple_stmt_iterator psi; + + for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) + { + phi = gsi_stmt (psi); + + iv = get_iv (data, PHI_RESULT (phi)); + if (!iv) + continue; + + var = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (loop)); + incr_iv = get_iv (data, var); + if (!incr_iv) + continue; + + /* If the increment is in the subloop, ignore it. */ + incr_bb = gimple_bb (SSA_NAME_DEF_STMT (var)); + if (incr_bb->loop_father != data->current_loop + || (incr_bb->flags & BB_IRREDUCIBLE_LOOP)) + continue; + + iv->biv_p = true; + incr_iv->biv_p = true; + } +} + +/* Checks whether STMT defines a linear induction variable and stores its + parameters to IV. */ + +static bool +find_givs_in_stmt_scev (struct ivopts_data *data, gimple stmt, affine_iv *iv) +{ + tree lhs; + struct loop *loop = data->current_loop; + + iv->base = NULL_TREE; + iv->step = NULL_TREE; + + if (gimple_code (stmt) != GIMPLE_ASSIGN) + return false; + + lhs = gimple_assign_lhs (stmt); + if (TREE_CODE (lhs) != SSA_NAME) + return false; + + if (!simple_iv (loop, loop_containing_stmt (stmt), lhs, iv, true)) + return false; + iv->base = expand_simple_operations (iv->base); + + if (contains_abnormal_ssa_name_p (iv->base) + || contains_abnormal_ssa_name_p (iv->step)) + return false; + + return true; +} + +/* Finds general ivs in statement STMT. */ + +static void +find_givs_in_stmt (struct ivopts_data *data, gimple stmt) +{ + affine_iv iv; + + if (!find_givs_in_stmt_scev (data, stmt, &iv)) + return; + + set_iv (data, gimple_assign_lhs (stmt), iv.base, iv.step); +} + +/* Finds general ivs in basic block BB. */ + +static void +find_givs_in_bb (struct ivopts_data *data, basic_block bb) +{ + gimple_stmt_iterator bsi; + + for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) + find_givs_in_stmt (data, gsi_stmt (bsi)); +} + +/* Finds general ivs. */ + +static void +find_givs (struct ivopts_data *data) +{ + struct loop *loop = data->current_loop; + basic_block *body = get_loop_body_in_dom_order (loop); + unsigned i; + + for (i = 0; i < loop->num_nodes; i++) + find_givs_in_bb (data, body[i]); + free (body); +} + +/* For each ssa name defined in LOOP determines whether it is an induction + variable and if so, its initial value and step. */ + +static bool +find_induction_variables (struct ivopts_data *data) +{ + unsigned i; + bitmap_iterator bi; + + if (!find_bivs (data)) + return false; + + find_givs (data); + mark_bivs (data); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + tree niter = niter_for_single_dom_exit (data); + + if (niter) + { + fprintf (dump_file, " number of iterations "); + print_generic_expr (dump_file, niter, TDF_SLIM); + fprintf (dump_file, "\n\n"); + }; + + fprintf (dump_file, "Induction variables:\n\n"); + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) + { + if (ver_info (data, i)->iv) + dump_iv (dump_file, ver_info (data, i)->iv); + } + } + + return true; +} + +/* Records a use of type USE_TYPE at *USE_P in STMT whose value is IV. */ + +static struct iv_use * +record_use (struct ivopts_data *data, tree *use_p, struct iv *iv, + gimple stmt, enum use_type use_type) +{ + struct iv_use *use = XCNEW (struct iv_use); + + use->id = n_iv_uses (data); + use->type = use_type; + use->iv = iv; + use->stmt = stmt; + use->op_p = use_p; + use->related_cands = BITMAP_ALLOC (NULL); + + /* To avoid showing ssa name in the dumps, if it was not reset by the + caller. */ + iv->ssa_name = NULL_TREE; + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_use (dump_file, use); + + VEC_safe_push (iv_use_p, heap, data->iv_uses, use); + + return use; +} + +/* Checks whether OP is a loop-level invariant and if so, records it. + NONLINEAR_USE is true if the invariant is used in a way we do not + handle specially. */ + +static void +record_invariant (struct ivopts_data *data, tree op, bool nonlinear_use) +{ + basic_block bb; + struct version_info *info; + + if (TREE_CODE (op) != SSA_NAME + || !is_gimple_reg (op)) + return; + + bb = gimple_bb (SSA_NAME_DEF_STMT (op)); + if (bb + && flow_bb_inside_loop_p (data->current_loop, bb)) + return; + + info = name_info (data, op); + info->name = op; + info->has_nonlin_use |= nonlinear_use; + if (!info->inv_id) + info->inv_id = ++data->max_inv_id; + bitmap_set_bit (data->relevant, SSA_NAME_VERSION (op)); +} + +/* Checks whether the use OP is interesting and if so, records it. */ + +static struct iv_use * +find_interesting_uses_op (struct ivopts_data *data, tree op) +{ + struct iv *iv; + struct iv *civ; + gimple stmt; + struct iv_use *use; + + if (TREE_CODE (op) != SSA_NAME) + return NULL; + + iv = get_iv (data, op); + if (!iv) + return NULL; + + if (iv->have_use_for) + { + use = iv_use (data, iv->use_id); + + gcc_assert (use->type == USE_NONLINEAR_EXPR); + return use; + } + + if (integer_zerop (iv->step)) + { + record_invariant (data, op, true); + return NULL; + } + iv->have_use_for = true; + + civ = XNEW (struct iv); + *civ = *iv; + + stmt = SSA_NAME_DEF_STMT (op); + gcc_assert (gimple_code (stmt) == GIMPLE_PHI + || is_gimple_assign (stmt)); + + use = record_use (data, NULL, civ, stmt, USE_NONLINEAR_EXPR); + iv->use_id = use->id; + + return use; +} + +/* Given a condition in statement STMT, checks whether it is a compare + of an induction variable and an invariant. If this is the case, + CONTROL_VAR is set to location of the iv, BOUND to the location of + the invariant, IV_VAR and IV_BOUND are set to the corresponding + induction variable descriptions, and true is returned. If this is not + the case, CONTROL_VAR and BOUND are set to the arguments of the + condition and false is returned. */ + +static bool +extract_cond_operands (struct ivopts_data *data, gimple stmt, + tree **control_var, tree **bound, + struct iv **iv_var, struct iv **iv_bound) +{ + /* The objects returned when COND has constant operands. */ + static struct iv const_iv; + static tree zero; + tree *op0 = &zero, *op1 = &zero, *tmp_op; + struct iv *iv0 = &const_iv, *iv1 = &const_iv, *tmp_iv; + bool ret = false; + + if (gimple_code (stmt) == GIMPLE_COND) + { + op0 = gimple_cond_lhs_ptr (stmt); + op1 = gimple_cond_rhs_ptr (stmt); + } + else + { + op0 = gimple_assign_rhs1_ptr (stmt); + op1 = gimple_assign_rhs2_ptr (stmt); + } + + zero = integer_zero_node; + const_iv.step = integer_zero_node; + + if (TREE_CODE (*op0) == SSA_NAME) + iv0 = get_iv (data, *op0); + if (TREE_CODE (*op1) == SSA_NAME) + iv1 = get_iv (data, *op1); + + /* Exactly one of the compared values must be an iv, and the other one must + be an invariant. */ + if (!iv0 || !iv1) + goto end; + + if (integer_zerop (iv0->step)) + { + /* Control variable may be on the other side. */ + tmp_op = op0; op0 = op1; op1 = tmp_op; + tmp_iv = iv0; iv0 = iv1; iv1 = tmp_iv; + } + ret = !integer_zerop (iv0->step) && integer_zerop (iv1->step); + +end: + if (control_var) + *control_var = op0;; + if (iv_var) + *iv_var = iv0;; + if (bound) + *bound = op1; + if (iv_bound) + *iv_bound = iv1; + + return ret; +} + +/* Checks whether the condition in STMT is interesting and if so, + records it. */ + +static void +find_interesting_uses_cond (struct ivopts_data *data, gimple stmt) +{ + tree *var_p, *bound_p; + struct iv *var_iv, *civ; + + if (!extract_cond_operands (data, stmt, &var_p, &bound_p, &var_iv, NULL)) + { + find_interesting_uses_op (data, *var_p); + find_interesting_uses_op (data, *bound_p); + return; + } + + civ = XNEW (struct iv); + *civ = *var_iv; + record_use (data, NULL, civ, stmt, USE_COMPARE); +} + +/* Returns true if expression EXPR is obviously invariant in LOOP, + i.e. if all its operands are defined outside of the LOOP. LOOP + should not be the function body. */ + +bool +expr_invariant_in_loop_p (struct loop *loop, tree expr) +{ + basic_block def_bb; + unsigned i, len; + + gcc_assert (loop_depth (loop) > 0); + + if (is_gimple_min_invariant (expr)) + return true; + + if (TREE_CODE (expr) == SSA_NAME) + { + def_bb = gimple_bb (SSA_NAME_DEF_STMT (expr)); + if (def_bb + && flow_bb_inside_loop_p (loop, def_bb)) + return false; + + return true; + } + + if (!EXPR_P (expr)) + return false; + + len = TREE_OPERAND_LENGTH (expr); + for (i = 0; i < len; i++) + if (!expr_invariant_in_loop_p (loop, TREE_OPERAND (expr, i))) + return false; + + return true; +} + +/* Returns true if statement STMT is obviously invariant in LOOP, + i.e. if all its operands on the RHS are defined outside of the LOOP. + LOOP should not be the function body. */ + +bool +stmt_invariant_in_loop_p (struct loop *loop, gimple stmt) +{ + unsigned i; + tree lhs; + + gcc_assert (loop_depth (loop) > 0); + + lhs = gimple_get_lhs (stmt); + for (i = 0; i < gimple_num_ops (stmt); i++) + { + tree op = gimple_op (stmt, i); + if (op != lhs && !expr_invariant_in_loop_p (loop, op)) + return false; + } + + return true; +} + +/* Cumulates the steps of indices into DATA and replaces their values with the + initial ones. Returns false when the value of the index cannot be determined. + Callback for for_each_index. */ + +struct ifs_ivopts_data +{ + struct ivopts_data *ivopts_data; + gimple stmt; + tree step; +}; + +static bool +idx_find_step (tree base, tree *idx, void *data) +{ + struct ifs_ivopts_data *dta = (struct ifs_ivopts_data *) data; + struct iv *iv; + tree step, iv_base, iv_step, lbound, off; + struct loop *loop = dta->ivopts_data->current_loop; + + if (TREE_CODE (base) == MISALIGNED_INDIRECT_REF + || TREE_CODE (base) == ALIGN_INDIRECT_REF) + return false; + + /* If base is a component ref, require that the offset of the reference + be invariant. */ + if (TREE_CODE (base) == COMPONENT_REF) + { + off = component_ref_field_offset (base); + return expr_invariant_in_loop_p (loop, off); + } + + /* If base is array, first check whether we will be able to move the + reference out of the loop (in order to take its address in strength + reduction). In order for this to work we need both lower bound + and step to be loop invariants. */ + if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF) + { + /* Moreover, for a range, the size needs to be invariant as well. */ + if (TREE_CODE (base) == ARRAY_RANGE_REF + && !expr_invariant_in_loop_p (loop, TYPE_SIZE (TREE_TYPE (base)))) + return false; + + step = array_ref_element_size (base); + lbound = array_ref_low_bound (base); + + if (!expr_invariant_in_loop_p (loop, step) + || !expr_invariant_in_loop_p (loop, lbound)) + return false; + } + + if (TREE_CODE (*idx) != SSA_NAME) + return true; + + iv = get_iv (dta->ivopts_data, *idx); + if (!iv) + return false; + + /* XXX We produce for a base of *D42 with iv->base being &x[0] + *&x[0], which is not folded and does not trigger the + ARRAY_REF path below. */ + *idx = iv->base; + + if (integer_zerop (iv->step)) + return true; + + if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF) + { + step = array_ref_element_size (base); + + /* We only handle addresses whose step is an integer constant. */ + if (TREE_CODE (step) != INTEGER_CST) + return false; + } + else + /* The step for pointer arithmetics already is 1 byte. */ + step = build_int_cst (sizetype, 1); + + iv_base = iv->base; + iv_step = iv->step; + if (!convert_affine_scev (dta->ivopts_data->current_loop, + sizetype, &iv_base, &iv_step, dta->stmt, + false)) + { + /* The index might wrap. */ + return false; + } + + step = fold_build2 (MULT_EXPR, sizetype, step, iv_step); + dta->step = fold_build2 (PLUS_EXPR, sizetype, dta->step, step); + + return true; +} + +/* Records use in index IDX. Callback for for_each_index. Ivopts data + object is passed to it in DATA. */ + +static bool +idx_record_use (tree base, tree *idx, + void *vdata) +{ + struct ivopts_data *data = (struct ivopts_data *) vdata; + find_interesting_uses_op (data, *idx); + if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF) + { + find_interesting_uses_op (data, array_ref_element_size (base)); + find_interesting_uses_op (data, array_ref_low_bound (base)); + } + return true; +} + +/* If we can prove that TOP = cst * BOT for some constant cst, + store cst to MUL and return true. Otherwise return false. + The returned value is always sign-extended, regardless of the + signedness of TOP and BOT. */ + +static bool +constant_multiple_of (tree top, tree bot, double_int *mul) +{ + tree mby; + enum tree_code code; + double_int res, p0, p1; + unsigned precision = TYPE_PRECISION (TREE_TYPE (top)); + + STRIP_NOPS (top); + STRIP_NOPS (bot); + + if (operand_equal_p (top, bot, 0)) + { + *mul = double_int_one; + return true; + } + + code = TREE_CODE (top); + switch (code) + { + case MULT_EXPR: + mby = TREE_OPERAND (top, 1); + if (TREE_CODE (mby) != INTEGER_CST) + return false; + + if (!constant_multiple_of (TREE_OPERAND (top, 0), bot, &res)) + return false; + + *mul = double_int_sext (double_int_mul (res, tree_to_double_int (mby)), + precision); + return true; + + case PLUS_EXPR: + case MINUS_EXPR: + if (!constant_multiple_of (TREE_OPERAND (top, 0), bot, &p0) + || !constant_multiple_of (TREE_OPERAND (top, 1), bot, &p1)) + return false; + + if (code == MINUS_EXPR) + p1 = double_int_neg (p1); + *mul = double_int_sext (double_int_add (p0, p1), precision); + return true; + + case INTEGER_CST: + if (TREE_CODE (bot) != INTEGER_CST) + return false; + + p0 = double_int_sext (tree_to_double_int (top), precision); + p1 = double_int_sext (tree_to_double_int (bot), precision); + if (double_int_zero_p (p1)) + return false; + *mul = double_int_sext (double_int_sdivmod (p0, p1, FLOOR_DIV_EXPR, &res), + precision); + return double_int_zero_p (res); + + default: + return false; + } +} + +/* Returns true if memory reference REF with step STEP may be unaligned. */ + +static bool +may_be_unaligned_p (tree ref, tree step) +{ + tree base; + tree base_type; + HOST_WIDE_INT bitsize; + HOST_WIDE_INT bitpos; + tree toffset; + enum machine_mode mode; + int unsignedp, volatilep; + unsigned base_align; + + /* TARGET_MEM_REFs are translated directly to valid MEMs on the target, + thus they are not misaligned. */ + if (TREE_CODE (ref) == TARGET_MEM_REF) + return false; + + /* The test below is basically copy of what expr.c:normal_inner_ref + does to check whether the object must be loaded by parts when + STRICT_ALIGNMENT is true. */ + base = get_inner_reference (ref, &bitsize, &bitpos, &toffset, &mode, + &unsignedp, &volatilep, true); + base_type = TREE_TYPE (base); + base_align = TYPE_ALIGN (base_type); + + if (mode != BLKmode) + { + double_int mul; + tree al = build_int_cst (TREE_TYPE (step), + GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT); + + if (base_align < GET_MODE_ALIGNMENT (mode) + || bitpos % GET_MODE_ALIGNMENT (mode) != 0 + || bitpos % BITS_PER_UNIT != 0) + return true; + + if (!constant_multiple_of (step, al, &mul)) + return true; + } + + return false; +} + +/* Return true if EXPR may be non-addressable. */ + +static bool +may_be_nonaddressable_p (tree expr) +{ + switch (TREE_CODE (expr)) + { + case TARGET_MEM_REF: + /* TARGET_MEM_REFs are translated directly to valid MEMs on the + target, thus they are always addressable. */ + return false; + + case COMPONENT_REF: + return DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)) + || may_be_nonaddressable_p (TREE_OPERAND (expr, 0)); + + case VIEW_CONVERT_EXPR: + /* This kind of view-conversions may wrap non-addressable objects + and make them look addressable. After some processing the + non-addressability may be uncovered again, causing ADDR_EXPRs + of inappropriate objects to be built. */ + if (is_gimple_reg (TREE_OPERAND (expr, 0)) + || !is_gimple_addressable (TREE_OPERAND (expr, 0))) + return true; + + /* ... fall through ... */ + + case ARRAY_REF: + case ARRAY_RANGE_REF: + return may_be_nonaddressable_p (TREE_OPERAND (expr, 0)); + + CASE_CONVERT: + return true; + + default: + break; + } + + return false; +} + +/* Finds addresses in *OP_P inside STMT. */ + +static void +find_interesting_uses_address (struct ivopts_data *data, gimple stmt, tree *op_p) +{ + tree base = *op_p, step = build_int_cst (sizetype, 0); + struct iv *civ; + struct ifs_ivopts_data ifs_ivopts_data; + + /* Do not play with volatile memory references. A bit too conservative, + perhaps, but safe. */ + if (gimple_has_volatile_ops (stmt)) + goto fail; + + /* Ignore bitfields for now. Not really something terribly complicated + to handle. TODO. */ + if (TREE_CODE (base) == BIT_FIELD_REF) + goto fail; + + base = unshare_expr (base); + + if (TREE_CODE (base) == TARGET_MEM_REF) + { + tree type = build_pointer_type (TREE_TYPE (base)); + tree astep; + + if (TMR_BASE (base) + && TREE_CODE (TMR_BASE (base)) == SSA_NAME) + { + civ = get_iv (data, TMR_BASE (base)); + if (!civ) + goto fail; + + TMR_BASE (base) = civ->base; + step = civ->step; + } + if (TMR_INDEX (base) + && TREE_CODE (TMR_INDEX (base)) == SSA_NAME) + { + civ = get_iv (data, TMR_INDEX (base)); + if (!civ) + goto fail; + + TMR_INDEX (base) = civ->base; + astep = civ->step; + + if (astep) + { + if (TMR_STEP (base)) + astep = fold_build2 (MULT_EXPR, type, TMR_STEP (base), astep); + + step = fold_build2 (PLUS_EXPR, type, step, astep); + } + } + + if (integer_zerop (step)) + goto fail; + base = tree_mem_ref_addr (type, base); + } + else + { + ifs_ivopts_data.ivopts_data = data; + ifs_ivopts_data.stmt = stmt; + ifs_ivopts_data.step = build_int_cst (sizetype, 0); + if (!for_each_index (&base, idx_find_step, &ifs_ivopts_data) + || integer_zerop (ifs_ivopts_data.step)) + goto fail; + step = ifs_ivopts_data.step; + + gcc_assert (TREE_CODE (base) != ALIGN_INDIRECT_REF); + gcc_assert (TREE_CODE (base) != MISALIGNED_INDIRECT_REF); + + /* Check that the base expression is addressable. This needs + to be done after substituting bases of IVs into it. */ + if (may_be_nonaddressable_p (base)) + goto fail; + + /* Moreover, on strict alignment platforms, check that it is + sufficiently aligned. */ + if (STRICT_ALIGNMENT && may_be_unaligned_p (base, step)) + goto fail; + + base = build_fold_addr_expr (base); + + /* Substituting bases of IVs into the base expression might + have caused folding opportunities. */ + if (TREE_CODE (base) == ADDR_EXPR) + { + tree *ref = &TREE_OPERAND (base, 0); + while (handled_component_p (*ref)) + ref = &TREE_OPERAND (*ref, 0); + if (TREE_CODE (*ref) == INDIRECT_REF) + *ref = fold_indirect_ref (*ref); + } + } + + civ = alloc_iv (base, step); + record_use (data, op_p, civ, stmt, USE_ADDRESS); + return; + +fail: + for_each_index (op_p, idx_record_use, data); +} + +/* Finds and records invariants used in STMT. */ + +static void +find_invariants_stmt (struct ivopts_data *data, gimple stmt) +{ + ssa_op_iter iter; + use_operand_p use_p; + tree op; + + FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE) + { + op = USE_FROM_PTR (use_p); + record_invariant (data, op, false); + } +} + +/* Finds interesting uses of induction variables in the statement STMT. */ + +static void +find_interesting_uses_stmt (struct ivopts_data *data, gimple stmt) +{ + struct iv *iv; + tree op, *lhs, *rhs; + ssa_op_iter iter; + use_operand_p use_p; + enum tree_code code; + + find_invariants_stmt (data, stmt); + + if (gimple_code (stmt) == GIMPLE_COND) + { + find_interesting_uses_cond (data, stmt); + return; + } + + if (is_gimple_assign (stmt)) + { + lhs = gimple_assign_lhs_ptr (stmt); + rhs = gimple_assign_rhs1_ptr (stmt); + + if (TREE_CODE (*lhs) == SSA_NAME) + { + /* If the statement defines an induction variable, the uses are not + interesting by themselves. */ + + iv = get_iv (data, *lhs); + + if (iv && !integer_zerop (iv->step)) + return; + } + + code = gimple_assign_rhs_code (stmt); + if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS + && (REFERENCE_CLASS_P (*rhs) + || is_gimple_val (*rhs))) + { + if (REFERENCE_CLASS_P (*rhs)) + find_interesting_uses_address (data, stmt, rhs); + else + find_interesting_uses_op (data, *rhs); + + if (REFERENCE_CLASS_P (*lhs)) + find_interesting_uses_address (data, stmt, lhs); + return; + } + else if (TREE_CODE_CLASS (code) == tcc_comparison) + { + find_interesting_uses_cond (data, stmt); + return; + } + + /* TODO -- we should also handle address uses of type + + memory = call (whatever); + + and + + call (memory). */ + } + + if (gimple_code (stmt) == GIMPLE_PHI + && gimple_bb (stmt) == data->current_loop->header) + { + iv = get_iv (data, PHI_RESULT (stmt)); + + if (iv && !integer_zerop (iv->step)) + return; + } + + FOR_EACH_PHI_OR_STMT_USE (use_p, stmt, iter, SSA_OP_USE) + { + op = USE_FROM_PTR (use_p); + + if (TREE_CODE (op) != SSA_NAME) + continue; + + iv = get_iv (data, op); + if (!iv) + continue; + + find_interesting_uses_op (data, op); + } +} + +/* Finds interesting uses of induction variables outside of loops + on loop exit edge EXIT. */ + +static void +find_interesting_uses_outside (struct ivopts_data *data, edge exit) +{ + gimple phi; + gimple_stmt_iterator psi; + tree def; + + for (psi = gsi_start_phis (exit->dest); !gsi_end_p (psi); gsi_next (&psi)) + { + phi = gsi_stmt (psi); + def = PHI_ARG_DEF_FROM_EDGE (phi, exit); + if (is_gimple_reg (def)) + find_interesting_uses_op (data, def); + } +} + +/* Finds uses of the induction variables that are interesting. */ + +static void +find_interesting_uses (struct ivopts_data *data) +{ + basic_block bb; + gimple_stmt_iterator bsi; + basic_block *body = get_loop_body (data->current_loop); + unsigned i; + struct version_info *info; + edge e; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Uses:\n\n"); + + for (i = 0; i < data->current_loop->num_nodes; i++) + { + edge_iterator ei; + bb = body[i]; + + FOR_EACH_EDGE (e, ei, bb->succs) + if (e->dest != EXIT_BLOCK_PTR + && !flow_bb_inside_loop_p (data->current_loop, e->dest)) + find_interesting_uses_outside (data, e); + + for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi)) + find_interesting_uses_stmt (data, gsi_stmt (bsi)); + for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) + find_interesting_uses_stmt (data, gsi_stmt (bsi)); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + bitmap_iterator bi; + + fprintf (dump_file, "\n"); + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) + { + info = ver_info (data, i); + if (info->inv_id) + { + fprintf (dump_file, " "); + print_generic_expr (dump_file, info->name, TDF_SLIM); + fprintf (dump_file, " is invariant (%d)%s\n", + info->inv_id, info->has_nonlin_use ? "" : ", eliminable"); + } + } + + fprintf (dump_file, "\n"); + } + + free (body); +} + +/* Strips constant offsets from EXPR and stores them to OFFSET. If INSIDE_ADDR + is true, assume we are inside an address. If TOP_COMPREF is true, assume + we are at the top-level of the processed address. */ + +static tree +strip_offset_1 (tree expr, bool inside_addr, bool top_compref, + unsigned HOST_WIDE_INT *offset) +{ + tree op0 = NULL_TREE, op1 = NULL_TREE, tmp, step; + enum tree_code code; + tree type, orig_type = TREE_TYPE (expr); + unsigned HOST_WIDE_INT off0, off1, st; + tree orig_expr = expr; + + STRIP_NOPS (expr); + + type = TREE_TYPE (expr); + code = TREE_CODE (expr); + *offset = 0; + + switch (code) + { + case INTEGER_CST: + if (!cst_and_fits_in_hwi (expr) + || integer_zerop (expr)) + return orig_expr; + + *offset = int_cst_value (expr); + return build_int_cst (orig_type, 0); + + case POINTER_PLUS_EXPR: + case PLUS_EXPR: + case MINUS_EXPR: + op0 = TREE_OPERAND (expr, 0); + op1 = TREE_OPERAND (expr, 1); + + op0 = strip_offset_1 (op0, false, false, &off0); + op1 = strip_offset_1 (op1, false, false, &off1); + + *offset = (code == MINUS_EXPR ? off0 - off1 : off0 + off1); + if (op0 == TREE_OPERAND (expr, 0) + && op1 == TREE_OPERAND (expr, 1)) + return orig_expr; + + if (integer_zerop (op1)) + expr = op0; + else if (integer_zerop (op0)) + { + if (code == MINUS_EXPR) + expr = fold_build1 (NEGATE_EXPR, type, op1); + else + expr = op1; + } + else + expr = fold_build2 (code, type, op0, op1); + + return fold_convert (orig_type, expr); + + case ARRAY_REF: + case ARRAY_RANGE_REF: + if (!inside_addr) + return orig_expr; + + step = array_ref_element_size (expr); + if (!cst_and_fits_in_hwi (step)) + break; + + st = int_cst_value (step); + op1 = TREE_OPERAND (expr, 1); + op1 = strip_offset_1 (op1, false, false, &off1); + *offset = off1 * st; + + if (top_compref + && integer_zerop (op1)) + { + /* Strip the component reference completely. */ + op0 = TREE_OPERAND (expr, 0); + op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0); + *offset += off0; + return op0; + } + break; + + case COMPONENT_REF: + if (!inside_addr) + return orig_expr; + + tmp = component_ref_field_offset (expr); + if (top_compref + && cst_and_fits_in_hwi (tmp)) + { + /* Strip the component reference completely. */ + op0 = TREE_OPERAND (expr, 0); + op0 = strip_offset_1 (op0, inside_addr, top_compref, &off0); + *offset = off0 + int_cst_value (tmp); + return op0; + } + break; + + case ADDR_EXPR: + op0 = TREE_OPERAND (expr, 0); + op0 = strip_offset_1 (op0, true, true, &off0); + *offset += off0; + + if (op0 == TREE_OPERAND (expr, 0)) + return orig_expr; + + expr = build_fold_addr_expr (op0); + return fold_convert (orig_type, expr); + + case INDIRECT_REF: + inside_addr = false; + break; + + default: + return orig_expr; + } + + /* Default handling of expressions for that we want to recurse into + the first operand. */ + op0 = TREE_OPERAND (expr, 0); + op0 = strip_offset_1 (op0, inside_addr, false, &off0); + *offset += off0; + + if (op0 == TREE_OPERAND (expr, 0) + && (!op1 || op1 == TREE_OPERAND (expr, 1))) + return orig_expr; + + expr = copy_node (expr); + TREE_OPERAND (expr, 0) = op0; + if (op1) + TREE_OPERAND (expr, 1) = op1; + + /* Inside address, we might strip the top level component references, + thus changing type of the expression. Handling of ADDR_EXPR + will fix that. */ + expr = fold_convert (orig_type, expr); + + return expr; +} + +/* Strips constant offsets from EXPR and stores them to OFFSET. */ + +static tree +strip_offset (tree expr, unsigned HOST_WIDE_INT *offset) +{ + return strip_offset_1 (expr, false, false, offset); +} + +/* Returns variant of TYPE that can be used as base for different uses. + We return unsigned type with the same precision, which avoids problems + with overflows. */ + +static tree +generic_type_for (tree type) +{ + if (POINTER_TYPE_P (type)) + return unsigned_type_for (type); + + if (TYPE_UNSIGNED (type)) + return type; + + return unsigned_type_for (type); +} + +/* Records invariants in *EXPR_P. Callback for walk_tree. DATA contains + the bitmap to that we should store it. */ + +static struct ivopts_data *fd_ivopts_data; +static tree +find_depends (tree *expr_p, int *ws ATTRIBUTE_UNUSED, void *data) +{ + bitmap *depends_on = (bitmap *) data; + struct version_info *info; + + if (TREE_CODE (*expr_p) != SSA_NAME) + return NULL_TREE; + info = name_info (fd_ivopts_data, *expr_p); + + if (!info->inv_id || info->has_nonlin_use) + return NULL_TREE; + + if (!*depends_on) + *depends_on = BITMAP_ALLOC (NULL); + bitmap_set_bit (*depends_on, info->inv_id); + + return NULL_TREE; +} + +/* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and + position to POS. If USE is not NULL, the candidate is set as related to + it. If both BASE and STEP are NULL, we add a pseudocandidate for the + replacement of the final value of the iv by a direct computation. */ + +static struct iv_cand * +add_candidate_1 (struct ivopts_data *data, + tree base, tree step, bool important, enum iv_position pos, + struct iv_use *use, gimple incremented_at) +{ + unsigned i; + struct iv_cand *cand = NULL; + tree type, orig_type; + + if (base) + { + orig_type = TREE_TYPE (base); + type = generic_type_for (orig_type); + if (type != orig_type) + { + base = fold_convert (type, base); + step = fold_convert (type, step); + } + } + + for (i = 0; i < n_iv_cands (data); i++) + { + cand = iv_cand (data, i); + + if (cand->pos != pos) + continue; + + if (cand->incremented_at != incremented_at) + continue; + + if (!cand->iv) + { + if (!base && !step) + break; + + continue; + } + + if (!base && !step) + continue; + + if (operand_equal_p (base, cand->iv->base, 0) + && operand_equal_p (step, cand->iv->step, 0)) + break; + } + + if (i == n_iv_cands (data)) + { + cand = XCNEW (struct iv_cand); + cand->id = i; + + if (!base && !step) + cand->iv = NULL; + else + cand->iv = alloc_iv (base, step); + + cand->pos = pos; + if (pos != IP_ORIGINAL && cand->iv) + { + cand->var_before = create_tmp_var_raw (TREE_TYPE (base), "ivtmp"); + cand->var_after = cand->var_before; + } + cand->important = important; + cand->incremented_at = incremented_at; + VEC_safe_push (iv_cand_p, heap, data->iv_candidates, cand); + + if (step + && TREE_CODE (step) != INTEGER_CST) + { + fd_ivopts_data = data; + walk_tree (&step, find_depends, &cand->depends_on, NULL); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_cand (dump_file, cand); + } + + if (important && !cand->important) + { + cand->important = true; + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Candidate %d is important\n", cand->id); + } + + if (use) + { + bitmap_set_bit (use->related_cands, i); + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Candidate %d is related to use %d\n", + cand->id, use->id); + } + + return cand; +} + +/* Returns true if incrementing the induction variable at the end of the LOOP + is allowed. + + The purpose is to avoid splitting latch edge with a biv increment, thus + creating a jump, possibly confusing other optimization passes and leaving + less freedom to scheduler. So we allow IP_END_POS only if IP_NORMAL_POS + is not available (so we do not have a better alternative), or if the latch + edge is already nonempty. */ + +static bool +allow_ip_end_pos_p (struct loop *loop) +{ + if (!ip_normal_pos (loop)) + return true; + + if (!empty_block_p (ip_end_pos (loop))) + return true; + + return false; +} + +/* Adds a candidate BASE + STEP * i. Important field is set to IMPORTANT and + position to POS. If USE is not NULL, the candidate is set as related to + it. The candidate computation is scheduled on all available positions. */ + +static void +add_candidate (struct ivopts_data *data, + tree base, tree step, bool important, struct iv_use *use) +{ + if (ip_normal_pos (data->current_loop)) + add_candidate_1 (data, base, step, important, IP_NORMAL, use, NULL); + if (ip_end_pos (data->current_loop) + && allow_ip_end_pos_p (data->current_loop)) + add_candidate_1 (data, base, step, important, IP_END, use, NULL); +} + +/* Add a standard "0 + 1 * iteration" iv candidate for a + type with SIZE bits. */ + +static void +add_standard_iv_candidates_for_size (struct ivopts_data *data, + unsigned int size) +{ + tree type = lang_hooks.types.type_for_size (size, true); + add_candidate (data, build_int_cst (type, 0), build_int_cst (type, 1), + true, NULL); +} + +/* Adds standard iv candidates. */ + +static void +add_standard_iv_candidates (struct ivopts_data *data) +{ + add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE); + + /* The same for a double-integer type if it is still fast enough. */ + if (BITS_PER_WORD >= INT_TYPE_SIZE * 2) + add_standard_iv_candidates_for_size (data, INT_TYPE_SIZE * 2); +} + + +/* Adds candidates bases on the old induction variable IV. */ + +static void +add_old_iv_candidates (struct ivopts_data *data, struct iv *iv) +{ + gimple phi; + tree def; + struct iv_cand *cand; + + add_candidate (data, iv->base, iv->step, true, NULL); + + /* The same, but with initial value zero. */ + if (POINTER_TYPE_P (TREE_TYPE (iv->base))) + add_candidate (data, size_int (0), iv->step, true, NULL); + else + add_candidate (data, build_int_cst (TREE_TYPE (iv->base), 0), + iv->step, true, NULL); + + phi = SSA_NAME_DEF_STMT (iv->ssa_name); + if (gimple_code (phi) == GIMPLE_PHI) + { + /* Additionally record the possibility of leaving the original iv + untouched. */ + def = PHI_ARG_DEF_FROM_EDGE (phi, loop_latch_edge (data->current_loop)); + cand = add_candidate_1 (data, + iv->base, iv->step, true, IP_ORIGINAL, NULL, + SSA_NAME_DEF_STMT (def)); + cand->var_before = iv->ssa_name; + cand->var_after = def; + } +} + +/* Adds candidates based on the old induction variables. */ + +static void +add_old_ivs_candidates (struct ivopts_data *data) +{ + unsigned i; + struct iv *iv; + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) + { + iv = ver_info (data, i)->iv; + if (iv && iv->biv_p && !integer_zerop (iv->step)) + add_old_iv_candidates (data, iv); + } +} + +/* Adds candidates based on the value of the induction variable IV and USE. */ + +static void +add_iv_value_candidates (struct ivopts_data *data, + struct iv *iv, struct iv_use *use) +{ + unsigned HOST_WIDE_INT offset; + tree base; + tree basetype; + + add_candidate (data, iv->base, iv->step, false, use); + + /* The same, but with initial value zero. Make such variable important, + since it is generic enough so that possibly many uses may be based + on it. */ + basetype = TREE_TYPE (iv->base); + if (POINTER_TYPE_P (basetype)) + basetype = sizetype; + add_candidate (data, build_int_cst (basetype, 0), + iv->step, true, use); + + /* Third, try removing the constant offset. Make sure to even + add a candidate for &a[0] vs. (T *)&a. */ + base = strip_offset (iv->base, &offset); + if (offset + || base != iv->base) + add_candidate (data, base, iv->step, false, use); +} + +/* Adds candidates based on the uses. */ + +static void +add_derived_ivs_candidates (struct ivopts_data *data) +{ + unsigned i; + + for (i = 0; i < n_iv_uses (data); i++) + { + struct iv_use *use = iv_use (data, i); + + if (!use) + continue; + + switch (use->type) + { + case USE_NONLINEAR_EXPR: + case USE_COMPARE: + case USE_ADDRESS: + /* Just add the ivs based on the value of the iv used here. */ + add_iv_value_candidates (data, use->iv, use); + break; + + default: + gcc_unreachable (); + } + } +} + +/* Record important candidates and add them to related_cands bitmaps + if needed. */ + +static void +record_important_candidates (struct ivopts_data *data) +{ + unsigned i; + struct iv_use *use; + + for (i = 0; i < n_iv_cands (data); i++) + { + struct iv_cand *cand = iv_cand (data, i); + + if (cand->important) + bitmap_set_bit (data->important_candidates, i); + } + + data->consider_all_candidates = (n_iv_cands (data) + <= CONSIDER_ALL_CANDIDATES_BOUND); + + if (data->consider_all_candidates) + { + /* We will not need "related_cands" bitmaps in this case, + so release them to decrease peak memory consumption. */ + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + BITMAP_FREE (use->related_cands); + } + } + else + { + /* Add important candidates to the related_cands bitmaps. */ + for (i = 0; i < n_iv_uses (data); i++) + bitmap_ior_into (iv_use (data, i)->related_cands, + data->important_candidates); + } +} + +/* Finds the candidates for the induction variables. */ + +static void +find_iv_candidates (struct ivopts_data *data) +{ + /* Add commonly used ivs. */ + add_standard_iv_candidates (data); + + /* Add old induction variables. */ + add_old_ivs_candidates (data); + + /* Add induction variables derived from uses. */ + add_derived_ivs_candidates (data); + + /* Record the important candidates. */ + record_important_candidates (data); +} + +/* Allocates the data structure mapping the (use, candidate) pairs to costs. + If consider_all_candidates is true, we use a two-dimensional array, otherwise + we allocate a simple list to every use. */ + +static void +alloc_use_cost_map (struct ivopts_data *data) +{ + unsigned i, size, s, j; + + for (i = 0; i < n_iv_uses (data); i++) + { + struct iv_use *use = iv_use (data, i); + bitmap_iterator bi; + + if (data->consider_all_candidates) + size = n_iv_cands (data); + else + { + s = 0; + EXECUTE_IF_SET_IN_BITMAP (use->related_cands, 0, j, bi) + { + s++; + } + + /* Round up to the power of two, so that moduling by it is fast. */ + for (size = 1; size < s; size <<= 1) + continue; + } + + use->n_map_members = size; + use->cost_map = XCNEWVEC (struct cost_pair, size); + } +} + +/* Returns description of computation cost of expression whose runtime + cost is RUNTIME and complexity corresponds to COMPLEXITY. */ + +static comp_cost +new_cost (unsigned runtime, unsigned complexity) +{ + comp_cost cost; + + cost.cost = runtime; + cost.complexity = complexity; + + return cost; +} + +/* Adds costs COST1 and COST2. */ + +static comp_cost +add_costs (comp_cost cost1, comp_cost cost2) +{ + cost1.cost += cost2.cost; + cost1.complexity += cost2.complexity; + + return cost1; +} +/* Subtracts costs COST1 and COST2. */ + +static comp_cost +sub_costs (comp_cost cost1, comp_cost cost2) +{ + cost1.cost -= cost2.cost; + cost1.complexity -= cost2.complexity; + + return cost1; +} + +/* Returns a negative number if COST1 < COST2, a positive number if + COST1 > COST2, and 0 if COST1 = COST2. */ + +static int +compare_costs (comp_cost cost1, comp_cost cost2) +{ + if (cost1.cost == cost2.cost) + return cost1.complexity - cost2.complexity; + + return cost1.cost - cost2.cost; +} + +/* Returns true if COST is infinite. */ + +static bool +infinite_cost_p (comp_cost cost) +{ + return cost.cost == INFTY; +} + +/* Sets cost of (USE, CANDIDATE) pair to COST and record that it depends + on invariants DEPENDS_ON and that the value used in expressing it + is VALUE.*/ + +static void +set_use_iv_cost (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand, + comp_cost cost, bitmap depends_on, tree value) +{ + unsigned i, s; + + if (infinite_cost_p (cost)) + { + BITMAP_FREE (depends_on); + return; + } + + if (data->consider_all_candidates) + { + use->cost_map[cand->id].cand = cand; + use->cost_map[cand->id].cost = cost; + use->cost_map[cand->id].depends_on = depends_on; + use->cost_map[cand->id].value = value; + return; + } + + /* n_map_members is a power of two, so this computes modulo. */ + s = cand->id & (use->n_map_members - 1); + for (i = s; i < use->n_map_members; i++) + if (!use->cost_map[i].cand) + goto found; + for (i = 0; i < s; i++) + if (!use->cost_map[i].cand) + goto found; + + gcc_unreachable (); + +found: + use->cost_map[i].cand = cand; + use->cost_map[i].cost = cost; + use->cost_map[i].depends_on = depends_on; + use->cost_map[i].value = value; +} + +/* Gets cost of (USE, CANDIDATE) pair. */ + +static struct cost_pair * +get_use_iv_cost (struct ivopts_data *data, struct iv_use *use, + struct iv_cand *cand) +{ + unsigned i, s; + struct cost_pair *ret; + + if (!cand) + return NULL; + + if (data->consider_all_candidates) + { + ret = use->cost_map + cand->id; + if (!ret->cand) + return NULL; + + return ret; + } + + /* n_map_members is a power of two, so this computes modulo. */ + s = cand->id & (use->n_map_members - 1); + for (i = s; i < use->n_map_members; i++) + if (use->cost_map[i].cand == cand) + return use->cost_map + i; + + for (i = 0; i < s; i++) + if (use->cost_map[i].cand == cand) + return use->cost_map + i; + + return NULL; +} + +/* Returns estimate on cost of computing SEQ. */ + +static unsigned +seq_cost (rtx seq, bool speed) +{ + unsigned cost = 0; + rtx set; + + for (; seq; seq = NEXT_INSN (seq)) + { + set = single_set (seq); + if (set) + cost += rtx_cost (set, SET,speed); + else + cost++; + } + + return cost; +} + +/* Produce DECL_RTL for object obj so it looks like it is stored in memory. */ +static rtx +produce_memory_decl_rtl (tree obj, int *regno) +{ + rtx x; + + gcc_assert (obj); + if (TREE_STATIC (obj) || DECL_EXTERNAL (obj)) + { + const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (obj)); + x = gen_rtx_SYMBOL_REF (Pmode, name); + SET_SYMBOL_REF_DECL (x, obj); + x = gen_rtx_MEM (DECL_MODE (obj), x); + targetm.encode_section_info (obj, x, true); + } + else + { + x = gen_raw_REG (Pmode, (*regno)++); + x = gen_rtx_MEM (DECL_MODE (obj), x); + } + + return x; +} + +/* Prepares decl_rtl for variables referred in *EXPR_P. Callback for + walk_tree. DATA contains the actual fake register number. */ + +static tree +prepare_decl_rtl (tree *expr_p, int *ws, void *data) +{ + tree obj = NULL_TREE; + rtx x = NULL_RTX; + int *regno = (int *) data; + + switch (TREE_CODE (*expr_p)) + { + case ADDR_EXPR: + for (expr_p = &TREE_OPERAND (*expr_p, 0); + handled_component_p (*expr_p); + expr_p = &TREE_OPERAND (*expr_p, 0)) + continue; + obj = *expr_p; + if (DECL_P (obj) && !DECL_RTL_SET_P (obj)) + x = produce_memory_decl_rtl (obj, regno); + break; + + case SSA_NAME: + *ws = 0; + obj = SSA_NAME_VAR (*expr_p); + if (!DECL_RTL_SET_P (obj)) + x = gen_raw_REG (DECL_MODE (obj), (*regno)++); + break; + + case VAR_DECL: + case PARM_DECL: + case RESULT_DECL: + *ws = 0; + obj = *expr_p; + + if (DECL_RTL_SET_P (obj)) + break; + + if (DECL_MODE (obj) == BLKmode) + x = produce_memory_decl_rtl (obj, regno); + else + x = gen_raw_REG (DECL_MODE (obj), (*regno)++); + + break; + + default: + break; + } + + if (x) + { + VEC_safe_push (tree, heap, decl_rtl_to_reset, obj); + SET_DECL_RTL (obj, x); + } + + return NULL_TREE; +} + +/* Determines cost of the computation of EXPR. */ + +static unsigned +computation_cost (tree expr, bool speed) +{ + rtx seq, rslt; + tree type = TREE_TYPE (expr); + unsigned cost; + /* Avoid using hard regs in ways which may be unsupported. */ + int regno = LAST_VIRTUAL_REGISTER + 1; + enum function_frequency real_frequency = cfun->function_frequency; + + cfun->function_frequency = FUNCTION_FREQUENCY_NORMAL; + crtl->maybe_hot_insn_p = speed; + walk_tree (&expr, prepare_decl_rtl, ®no, NULL); + start_sequence (); + rslt = expand_expr (expr, NULL_RTX, TYPE_MODE (type), EXPAND_NORMAL); + seq = get_insns (); + end_sequence (); + default_rtl_profile (); + cfun->function_frequency = real_frequency; + + cost = seq_cost (seq, speed); + if (MEM_P (rslt)) + cost += address_cost (XEXP (rslt, 0), TYPE_MODE (type), speed); + + return cost; +} + +/* Returns variable containing the value of candidate CAND at statement AT. */ + +static tree +var_at_stmt (struct loop *loop, struct iv_cand *cand, gimple stmt) +{ + if (stmt_after_increment (loop, cand, stmt)) + return cand->var_after; + else + return cand->var_before; +} + +/* Return the most significant (sign) bit of T. Similar to tree_int_cst_msb, + but the bit is determined from TYPE_PRECISION, not MODE_BITSIZE. */ + +int +tree_int_cst_sign_bit (const_tree t) +{ + unsigned bitno = TYPE_PRECISION (TREE_TYPE (t)) - 1; + unsigned HOST_WIDE_INT w; + + if (bitno < HOST_BITS_PER_WIDE_INT) + w = TREE_INT_CST_LOW (t); + else + { + w = TREE_INT_CST_HIGH (t); + bitno -= HOST_BITS_PER_WIDE_INT; + } + + return (w >> bitno) & 1; +} + +/* If A is (TYPE) BA and B is (TYPE) BB, and the types of BA and BB have the + same precision that is at least as wide as the precision of TYPE, stores + BA to A and BB to B, and returns the type of BA. Otherwise, returns the + type of A and B. */ + +static tree +determine_common_wider_type (tree *a, tree *b) +{ + tree wider_type = NULL; + tree suba, subb; + tree atype = TREE_TYPE (*a); + + if (CONVERT_EXPR_P (*a)) + { + suba = TREE_OPERAND (*a, 0); + wider_type = TREE_TYPE (suba); + if (TYPE_PRECISION (wider_type) < TYPE_PRECISION (atype)) + return atype; + } + else + return atype; + + if (CONVERT_EXPR_P (*b)) + { + subb = TREE_OPERAND (*b, 0); + if (TYPE_PRECISION (wider_type) != TYPE_PRECISION (TREE_TYPE (subb))) + return atype; + } + else + return atype; + + *a = suba; + *b = subb; + return wider_type; +} + +/* Determines the expression by that USE is expressed from induction variable + CAND at statement AT in LOOP. The expression is stored in a decomposed + form into AFF. Returns false if USE cannot be expressed using CAND. */ + +static bool +get_computation_aff (struct loop *loop, + struct iv_use *use, struct iv_cand *cand, gimple at, + struct affine_tree_combination *aff) +{ + tree ubase = use->iv->base; + tree ustep = use->iv->step; + tree cbase = cand->iv->base; + tree cstep = cand->iv->step, cstep_common; + tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase); + tree common_type, var; + tree uutype; + aff_tree cbase_aff, var_aff; + double_int rat; + + if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype)) + { + /* We do not have a precision to express the values of use. */ + return false; + } + + var = var_at_stmt (loop, cand, at); + uutype = unsigned_type_for (utype); + + /* If the conversion is not noop, perform it. */ + if (TYPE_PRECISION (utype) < TYPE_PRECISION (ctype)) + { + cstep = fold_convert (uutype, cstep); + cbase = fold_convert (uutype, cbase); + var = fold_convert (uutype, var); + } + + if (!constant_multiple_of (ustep, cstep, &rat)) + return false; + + /* In case both UBASE and CBASE are shortened to UUTYPE from some common + type, we achieve better folding by computing their difference in this + wider type, and cast the result to UUTYPE. We do not need to worry about + overflows, as all the arithmetics will in the end be performed in UUTYPE + anyway. */ + common_type = determine_common_wider_type (&ubase, &cbase); + + /* use = ubase - ratio * cbase + ratio * var. */ + tree_to_aff_combination (ubase, common_type, aff); + tree_to_aff_combination (cbase, common_type, &cbase_aff); + tree_to_aff_combination (var, uutype, &var_aff); + + /* We need to shift the value if we are after the increment. */ + if (stmt_after_increment (loop, cand, at)) + { + aff_tree cstep_aff; + + if (common_type != uutype) + cstep_common = fold_convert (common_type, cstep); + else + cstep_common = cstep; + + tree_to_aff_combination (cstep_common, common_type, &cstep_aff); + aff_combination_add (&cbase_aff, &cstep_aff); + } + + aff_combination_scale (&cbase_aff, double_int_neg (rat)); + aff_combination_add (aff, &cbase_aff); + if (common_type != uutype) + aff_combination_convert (aff, uutype); + + aff_combination_scale (&var_aff, rat); + aff_combination_add (aff, &var_aff); + + return true; +} + +/* Determines the expression by that USE is expressed from induction variable + CAND at statement AT in LOOP. The computation is unshared. */ + +static tree +get_computation_at (struct loop *loop, + struct iv_use *use, struct iv_cand *cand, gimple at) +{ + aff_tree aff; + tree type = TREE_TYPE (use->iv->base); + + if (!get_computation_aff (loop, use, cand, at, &aff)) + return NULL_TREE; + unshare_aff_combination (&aff); + return fold_convert (type, aff_combination_to_tree (&aff)); +} + +/* Determines the expression by that USE is expressed from induction variable + CAND in LOOP. The computation is unshared. */ + +static tree +get_computation (struct loop *loop, struct iv_use *use, struct iv_cand *cand) +{ + return get_computation_at (loop, use, cand, use->stmt); +} + +/* Returns cost of addition in MODE. */ + +static unsigned +add_cost (enum machine_mode mode, bool speed) +{ + static unsigned costs[NUM_MACHINE_MODES]; + rtx seq; + unsigned cost; + + if (costs[mode]) + return costs[mode]; + + start_sequence (); + force_operand (gen_rtx_fmt_ee (PLUS, mode, + gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1), + gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 2)), + NULL_RTX); + seq = get_insns (); + end_sequence (); + + cost = seq_cost (seq, speed); + if (!cost) + cost = 1; + + costs[mode] = cost; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Addition in %s costs %d\n", + GET_MODE_NAME (mode), cost); + return cost; +} + +/* Entry in a hashtable of already known costs for multiplication. */ +struct mbc_entry +{ + HOST_WIDE_INT cst; /* The constant to multiply by. */ + enum machine_mode mode; /* In mode. */ + unsigned cost; /* The cost. */ +}; + +/* Counts hash value for the ENTRY. */ + +static hashval_t +mbc_entry_hash (const void *entry) +{ + const struct mbc_entry *e = (const struct mbc_entry *) entry; + + return 57 * (hashval_t) e->mode + (hashval_t) (e->cst % 877); +} + +/* Compares the hash table entries ENTRY1 and ENTRY2. */ + +static int +mbc_entry_eq (const void *entry1, const void *entry2) +{ + const struct mbc_entry *e1 = (const struct mbc_entry *) entry1; + const struct mbc_entry *e2 = (const struct mbc_entry *) entry2; + + return (e1->mode == e2->mode + && e1->cst == e2->cst); +} + +/* Returns cost of multiplication by constant CST in MODE. */ + +unsigned +multiply_by_cost (HOST_WIDE_INT cst, enum machine_mode mode, bool speed) +{ + static htab_t costs; + struct mbc_entry **cached, act; + rtx seq; + unsigned cost; + + if (!costs) + costs = htab_create (100, mbc_entry_hash, mbc_entry_eq, free); + + act.mode = mode; + act.cst = cst; + cached = (struct mbc_entry **) htab_find_slot (costs, &act, INSERT); + if (*cached) + return (*cached)->cost; + + *cached = XNEW (struct mbc_entry); + (*cached)->mode = mode; + (*cached)->cst = cst; + + start_sequence (); + expand_mult (mode, gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1), + gen_int_mode (cst, mode), NULL_RTX, 0); + seq = get_insns (); + end_sequence (); + + cost = seq_cost (seq, speed); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Multiplication by %d in %s costs %d\n", + (int) cst, GET_MODE_NAME (mode), cost); + + (*cached)->cost = cost; + + return cost; +} + +/* Returns true if multiplying by RATIO is allowed in an address. Test the + validity for a memory reference accessing memory of mode MODE. */ + +bool +multiplier_allowed_in_address_p (HOST_WIDE_INT ratio, enum machine_mode mode) +{ +#define MAX_RATIO 128 + static sbitmap valid_mult[MAX_MACHINE_MODE]; + + if (!valid_mult[mode]) + { + rtx reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); + rtx addr; + HOST_WIDE_INT i; + + valid_mult[mode] = sbitmap_alloc (2 * MAX_RATIO + 1); + sbitmap_zero (valid_mult[mode]); + addr = gen_rtx_fmt_ee (MULT, Pmode, reg1, NULL_RTX); + for (i = -MAX_RATIO; i <= MAX_RATIO; i++) + { + XEXP (addr, 1) = gen_int_mode (i, Pmode); + if (memory_address_p (mode, addr)) + SET_BIT (valid_mult[mode], i + MAX_RATIO); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " allowed multipliers:"); + for (i = -MAX_RATIO; i <= MAX_RATIO; i++) + if (TEST_BIT (valid_mult[mode], i + MAX_RATIO)) + fprintf (dump_file, " %d", (int) i); + fprintf (dump_file, "\n"); + fprintf (dump_file, "\n"); + } + } + + if (ratio > MAX_RATIO || ratio < -MAX_RATIO) + return false; + + return TEST_BIT (valid_mult[mode], ratio + MAX_RATIO); +} + +/* Returns cost of address in shape symbol + var + OFFSET + RATIO * index. + If SYMBOL_PRESENT is false, symbol is omitted. If VAR_PRESENT is false, + variable is omitted. Compute the cost for a memory reference that accesses + a memory location of mode MEM_MODE. + + TODO -- there must be some better way. This all is quite crude. */ + +static comp_cost +get_address_cost (bool symbol_present, bool var_present, + unsigned HOST_WIDE_INT offset, HOST_WIDE_INT ratio, + enum machine_mode mem_mode, + bool speed) +{ + static bool initialized[MAX_MACHINE_MODE]; + static HOST_WIDE_INT rat[MAX_MACHINE_MODE], off[MAX_MACHINE_MODE]; + static HOST_WIDE_INT min_offset[MAX_MACHINE_MODE], max_offset[MAX_MACHINE_MODE]; + static unsigned costs[MAX_MACHINE_MODE][2][2][2][2]; + unsigned cost, acost, complexity; + bool offset_p, ratio_p; + HOST_WIDE_INT s_offset; + unsigned HOST_WIDE_INT mask; + unsigned bits; + + if (!initialized[mem_mode]) + { + HOST_WIDE_INT i; + HOST_WIDE_INT start = BIGGEST_ALIGNMENT / BITS_PER_UNIT; + int old_cse_not_expected; + unsigned sym_p, var_p, off_p, rat_p, add_c; + rtx seq, addr, base; + rtx reg0, reg1; + + initialized[mem_mode] = true; + + reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); + + addr = gen_rtx_fmt_ee (PLUS, Pmode, reg1, NULL_RTX); + for (i = start; i <= 1 << 20; i <<= 1) + { + XEXP (addr, 1) = gen_int_mode (i, Pmode); + if (!memory_address_p (mem_mode, addr)) + break; + } + max_offset[mem_mode] = i == start ? 0 : i >> 1; + off[mem_mode] = max_offset[mem_mode]; + + for (i = start; i <= 1 << 20; i <<= 1) + { + XEXP (addr, 1) = gen_int_mode (-i, Pmode); + if (!memory_address_p (mem_mode, addr)) + break; + } + min_offset[mem_mode] = i == start ? 0 : -(i >> 1); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "get_address_cost:\n"); + fprintf (dump_file, " min offset %s %d\n", + GET_MODE_NAME (mem_mode), + (int) min_offset[mem_mode]); + fprintf (dump_file, " max offset %s %d\n", + GET_MODE_NAME (mem_mode), + (int) max_offset[mem_mode]); + } + + rat[mem_mode] = 1; + for (i = 2; i <= MAX_RATIO; i++) + if (multiplier_allowed_in_address_p (i, mem_mode)) + { + rat[mem_mode] = i; + break; + } + + /* Compute the cost of various addressing modes. */ + acost = 0; + reg0 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); + reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 2); + + for (i = 0; i < 16; i++) + { + sym_p = i & 1; + var_p = (i >> 1) & 1; + off_p = (i >> 2) & 1; + rat_p = (i >> 3) & 1; + + addr = reg0; + if (rat_p) + addr = gen_rtx_fmt_ee (MULT, Pmode, addr, + gen_int_mode (rat[mem_mode], Pmode)); + + if (var_p) + addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, reg1); + + if (sym_p) + { + base = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup ("")); + /* ??? We can run into trouble with some backends by presenting + it with symbols which haven't been properly passed through + targetm.encode_section_info. By setting the local bit, we + enhance the probability of things working. */ + SYMBOL_REF_FLAGS (base) = SYMBOL_FLAG_LOCAL; + + if (off_p) + base = gen_rtx_fmt_e (CONST, Pmode, + gen_rtx_fmt_ee (PLUS, Pmode, + base, + gen_int_mode (off[mem_mode], + Pmode))); + } + else if (off_p) + base = gen_int_mode (off[mem_mode], Pmode); + else + base = NULL_RTX; + + if (base) + addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, base); + + start_sequence (); + /* To avoid splitting addressing modes, pretend that no cse will + follow. */ + old_cse_not_expected = cse_not_expected; + cse_not_expected = true; + addr = memory_address (mem_mode, addr); + cse_not_expected = old_cse_not_expected; + seq = get_insns (); + end_sequence (); + + acost = seq_cost (seq, speed); + acost += address_cost (addr, mem_mode, speed); + + if (!acost) + acost = 1; + costs[mem_mode][sym_p][var_p][off_p][rat_p] = acost; + } + + /* On some targets, it is quite expensive to load symbol to a register, + which makes addresses that contain symbols look much more expensive. + However, the symbol will have to be loaded in any case before the + loop (and quite likely we have it in register already), so it does not + make much sense to penalize them too heavily. So make some final + tweaks for the SYMBOL_PRESENT modes: + + If VAR_PRESENT is false, and the mode obtained by changing symbol to + var is cheaper, use this mode with small penalty. + If VAR_PRESENT is true, try whether the mode with + SYMBOL_PRESENT = false is cheaper even with cost of addition, and + if this is the case, use it. */ + add_c = add_cost (Pmode, speed); + for (i = 0; i < 8; i++) + { + var_p = i & 1; + off_p = (i >> 1) & 1; + rat_p = (i >> 2) & 1; + + acost = costs[mem_mode][0][1][off_p][rat_p] + 1; + if (var_p) + acost += add_c; + + if (acost < costs[mem_mode][1][var_p][off_p][rat_p]) + costs[mem_mode][1][var_p][off_p][rat_p] = acost; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Address costs:\n"); + + for (i = 0; i < 16; i++) + { + sym_p = i & 1; + var_p = (i >> 1) & 1; + off_p = (i >> 2) & 1; + rat_p = (i >> 3) & 1; + + fprintf (dump_file, " "); + if (sym_p) + fprintf (dump_file, "sym + "); + if (var_p) + fprintf (dump_file, "var + "); + if (off_p) + fprintf (dump_file, "cst + "); + if (rat_p) + fprintf (dump_file, "rat * "); + + acost = costs[mem_mode][sym_p][var_p][off_p][rat_p]; + fprintf (dump_file, "index costs %d\n", acost); + } + fprintf (dump_file, "\n"); + } + } + + bits = GET_MODE_BITSIZE (Pmode); + mask = ~(~(unsigned HOST_WIDE_INT) 0 << (bits - 1) << 1); + offset &= mask; + if ((offset >> (bits - 1) & 1)) + offset |= ~mask; + s_offset = offset; + + cost = 0; + offset_p = (s_offset != 0 + && min_offset[mem_mode] <= s_offset + && s_offset <= max_offset[mem_mode]); + ratio_p = (ratio != 1 + && multiplier_allowed_in_address_p (ratio, mem_mode)); + + if (ratio != 1 && !ratio_p) + cost += multiply_by_cost (ratio, Pmode, speed); + + if (s_offset && !offset_p && !symbol_present) + cost += add_cost (Pmode, speed); + + acost = costs[mem_mode][symbol_present][var_present][offset_p][ratio_p]; + complexity = (symbol_present != 0) + (var_present != 0) + offset_p + ratio_p; + return new_cost (cost + acost, complexity); +} + +/* Estimates cost of forcing expression EXPR into a variable. */ + +static comp_cost +force_expr_to_var_cost (tree expr, bool speed) +{ + static bool costs_initialized = false; + static unsigned integer_cost [2]; + static unsigned symbol_cost [2]; + static unsigned address_cost [2]; + tree op0, op1; + comp_cost cost0, cost1, cost; + enum machine_mode mode; + + if (!costs_initialized) + { + tree type = build_pointer_type (integer_type_node); + tree var, addr; + rtx x; + int i; + + var = create_tmp_var_raw (integer_type_node, "test_var"); + TREE_STATIC (var) = 1; + x = produce_memory_decl_rtl (var, NULL); + SET_DECL_RTL (var, x); + + addr = build1 (ADDR_EXPR, type, var); + + + for (i = 0; i < 2; i++) + { + integer_cost[i] = computation_cost (build_int_cst (integer_type_node, + 2000), i); + + symbol_cost[i] = computation_cost (addr, i) + 1; + + address_cost[i] + = computation_cost (build2 (POINTER_PLUS_EXPR, type, + addr, + build_int_cst (sizetype, 2000)), i) + 1; + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "force_expr_to_var_cost %s costs:\n", i ? "speed" : "size"); + fprintf (dump_file, " integer %d\n", (int) integer_cost[i]); + fprintf (dump_file, " symbol %d\n", (int) symbol_cost[i]); + fprintf (dump_file, " address %d\n", (int) address_cost[i]); + fprintf (dump_file, " other %d\n", (int) target_spill_cost[i]); + fprintf (dump_file, "\n"); + } + } + + costs_initialized = true; + } + + STRIP_NOPS (expr); + + if (SSA_VAR_P (expr)) + return zero_cost; + + if (is_gimple_min_invariant (expr)) + { + if (TREE_CODE (expr) == INTEGER_CST) + return new_cost (integer_cost [speed], 0); + + if (TREE_CODE (expr) == ADDR_EXPR) + { + tree obj = TREE_OPERAND (expr, 0); + + if (TREE_CODE (obj) == VAR_DECL + || TREE_CODE (obj) == PARM_DECL + || TREE_CODE (obj) == RESULT_DECL) + return new_cost (symbol_cost [speed], 0); + } + + return new_cost (address_cost [speed], 0); + } + + switch (TREE_CODE (expr)) + { + case POINTER_PLUS_EXPR: + case PLUS_EXPR: + case MINUS_EXPR: + case MULT_EXPR: + op0 = TREE_OPERAND (expr, 0); + op1 = TREE_OPERAND (expr, 1); + STRIP_NOPS (op0); + STRIP_NOPS (op1); + + if (is_gimple_val (op0)) + cost0 = zero_cost; + else + cost0 = force_expr_to_var_cost (op0, speed); + + if (is_gimple_val (op1)) + cost1 = zero_cost; + else + cost1 = force_expr_to_var_cost (op1, speed); + + break; + + default: + /* Just an arbitrary value, FIXME. */ + return new_cost (target_spill_cost[speed], 0); + } + + mode = TYPE_MODE (TREE_TYPE (expr)); + switch (TREE_CODE (expr)) + { + case POINTER_PLUS_EXPR: + case PLUS_EXPR: + case MINUS_EXPR: + cost = new_cost (add_cost (mode, speed), 0); + break; + + case MULT_EXPR: + if (cst_and_fits_in_hwi (op0)) + cost = new_cost (multiply_by_cost (int_cst_value (op0), mode, speed), 0); + else if (cst_and_fits_in_hwi (op1)) + cost = new_cost (multiply_by_cost (int_cst_value (op1), mode, speed), 0); + else + return new_cost (target_spill_cost [speed], 0); + break; + + default: + gcc_unreachable (); + } + + cost = add_costs (cost, cost0); + cost = add_costs (cost, cost1); + + /* Bound the cost by target_spill_cost. The parts of complicated + computations often are either loop invariant or at least can + be shared between several iv uses, so letting this grow without + limits would not give reasonable results. */ + if (cost.cost > target_spill_cost [speed]) + cost.cost = target_spill_cost [speed]; + + return cost; +} + +/* Estimates cost of forcing EXPR into a variable. DEPENDS_ON is a set of the + invariants the computation depends on. */ + +static comp_cost +force_var_cost (struct ivopts_data *data, + tree expr, bitmap *depends_on) +{ + if (depends_on) + { + fd_ivopts_data = data; + walk_tree (&expr, find_depends, depends_on, NULL); + } + + return force_expr_to_var_cost (expr, data->speed); +} + +/* Estimates cost of expressing address ADDR as var + symbol + offset. The + value of offset is added to OFFSET, SYMBOL_PRESENT and VAR_PRESENT are set + to false if the corresponding part is missing. DEPENDS_ON is a set of the + invariants the computation depends on. */ + +static comp_cost +split_address_cost (struct ivopts_data *data, + tree addr, bool *symbol_present, bool *var_present, + unsigned HOST_WIDE_INT *offset, bitmap *depends_on) +{ + tree core; + HOST_WIDE_INT bitsize; + HOST_WIDE_INT bitpos; + tree toffset; + enum machine_mode mode; + int unsignedp, volatilep; + + core = get_inner_reference (addr, &bitsize, &bitpos, &toffset, &mode, + &unsignedp, &volatilep, false); + + if (toffset != 0 + || bitpos % BITS_PER_UNIT != 0 + || TREE_CODE (core) != VAR_DECL) + { + *symbol_present = false; + *var_present = true; + fd_ivopts_data = data; + walk_tree (&addr, find_depends, depends_on, NULL); + return new_cost (target_spill_cost[data->speed], 0); + } + + *offset += bitpos / BITS_PER_UNIT; + if (TREE_STATIC (core) + || DECL_EXTERNAL (core)) + { + *symbol_present = true; + *var_present = false; + return zero_cost; + } + + *symbol_present = false; + *var_present = true; + return zero_cost; +} + +/* Estimates cost of expressing difference of addresses E1 - E2 as + var + symbol + offset. The value of offset is added to OFFSET, + SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding + part is missing. DEPENDS_ON is a set of the invariants the computation + depends on. */ + +static comp_cost +ptr_difference_cost (struct ivopts_data *data, + tree e1, tree e2, bool *symbol_present, bool *var_present, + unsigned HOST_WIDE_INT *offset, bitmap *depends_on) +{ + HOST_WIDE_INT diff = 0; + comp_cost cost; + bool speed = optimize_loop_for_speed_p (data->current_loop); + + gcc_assert (TREE_CODE (e1) == ADDR_EXPR); + + if (ptr_difference_const (e1, e2, &diff)) + { + *offset += diff; + *symbol_present = false; + *var_present = false; + return zero_cost; + } + + if (integer_zerop (e2)) + return split_address_cost (data, TREE_OPERAND (e1, 0), + symbol_present, var_present, offset, depends_on); + + *symbol_present = false; + *var_present = true; + + cost = force_var_cost (data, e1, depends_on); + cost = add_costs (cost, force_var_cost (data, e2, depends_on)); + cost.cost += add_cost (Pmode, speed); + + return cost; +} + +/* Estimates cost of expressing difference E1 - E2 as + var + symbol + offset. The value of offset is added to OFFSET, + SYMBOL_PRESENT and VAR_PRESENT are set to false if the corresponding + part is missing. DEPENDS_ON is a set of the invariants the computation + depends on. */ + +static comp_cost +difference_cost (struct ivopts_data *data, + tree e1, tree e2, bool *symbol_present, bool *var_present, + unsigned HOST_WIDE_INT *offset, bitmap *depends_on) +{ + comp_cost cost; + enum machine_mode mode = TYPE_MODE (TREE_TYPE (e1)); + unsigned HOST_WIDE_INT off1, off2; + + e1 = strip_offset (e1, &off1); + e2 = strip_offset (e2, &off2); + *offset += off1 - off2; + + STRIP_NOPS (e1); + STRIP_NOPS (e2); + + if (TREE_CODE (e1) == ADDR_EXPR) + return ptr_difference_cost (data, e1, e2, symbol_present, var_present, offset, + depends_on); + *symbol_present = false; + + if (operand_equal_p (e1, e2, 0)) + { + *var_present = false; + return zero_cost; + } + *var_present = true; + if (integer_zerop (e2)) + return force_var_cost (data, e1, depends_on); + + if (integer_zerop (e1)) + { + cost = force_var_cost (data, e2, depends_on); + cost.cost += multiply_by_cost (-1, mode, data->speed); + + return cost; + } + + cost = force_var_cost (data, e1, depends_on); + cost = add_costs (cost, force_var_cost (data, e2, depends_on)); + cost.cost += add_cost (mode, data->speed); + + return cost; +} + +/* Determines the cost of the computation by that USE is expressed + from induction variable CAND. If ADDRESS_P is true, we just need + to create an address from it, otherwise we want to get it into + register. A set of invariants we depend on is stored in + DEPENDS_ON. AT is the statement at that the value is computed. */ + +static comp_cost +get_computation_cost_at (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand, + bool address_p, bitmap *depends_on, gimple at) +{ + tree ubase = use->iv->base, ustep = use->iv->step; + tree cbase, cstep; + tree utype = TREE_TYPE (ubase), ctype; + unsigned HOST_WIDE_INT cstepi, offset = 0; + HOST_WIDE_INT ratio, aratio; + bool var_present, symbol_present; + comp_cost cost; + unsigned n_sums; + double_int rat; + bool speed = optimize_bb_for_speed_p (gimple_bb (at)); + + *depends_on = NULL; + + /* Only consider real candidates. */ + if (!cand->iv) + return infinite_cost; + + cbase = cand->iv->base; + cstep = cand->iv->step; + ctype = TREE_TYPE (cbase); + + if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype)) + { + /* We do not have a precision to express the values of use. */ + return infinite_cost; + } + + if (address_p) + { + /* Do not try to express address of an object with computation based + on address of a different object. This may cause problems in rtl + level alias analysis (that does not expect this to be happening, + as this is illegal in C), and would be unlikely to be useful + anyway. */ + if (use->iv->base_object + && cand->iv->base_object + && !operand_equal_p (use->iv->base_object, cand->iv->base_object, 0)) + return infinite_cost; + } + + if (TYPE_PRECISION (utype) != TYPE_PRECISION (ctype)) + { + /* TODO -- add direct handling of this case. */ + goto fallback; + } + + /* CSTEPI is removed from the offset in case statement is after the + increment. If the step is not constant, we use zero instead. + This is a bit imprecise (there is the extra addition), but + redundancy elimination is likely to transform the code so that + it uses value of the variable before increment anyway, + so it is not that much unrealistic. */ + if (cst_and_fits_in_hwi (cstep)) + cstepi = int_cst_value (cstep); + else + cstepi = 0; + + if (!constant_multiple_of (ustep, cstep, &rat)) + return infinite_cost; + + if (double_int_fits_in_shwi_p (rat)) + ratio = double_int_to_shwi (rat); + else + return infinite_cost; + + /* use = ubase + ratio * (var - cbase). If either cbase is a constant + or ratio == 1, it is better to handle this like + + ubase - ratio * cbase + ratio * var + + (also holds in the case ratio == -1, TODO. */ + + if (cst_and_fits_in_hwi (cbase)) + { + offset = - ratio * int_cst_value (cbase); + cost = difference_cost (data, + ubase, build_int_cst (utype, 0), + &symbol_present, &var_present, &offset, + depends_on); + } + else if (ratio == 1) + { + cost = difference_cost (data, + ubase, cbase, + &symbol_present, &var_present, &offset, + depends_on); + } + else + { + cost = force_var_cost (data, cbase, depends_on); + cost.cost += add_cost (TYPE_MODE (ctype), data->speed); + cost = add_costs (cost, + difference_cost (data, + ubase, build_int_cst (utype, 0), + &symbol_present, &var_present, + &offset, depends_on)); + } + + /* If we are after the increment, the value of the candidate is higher by + one iteration. */ + if (stmt_after_increment (data->current_loop, cand, at)) + offset -= ratio * cstepi; + + /* Now the computation is in shape symbol + var1 + const + ratio * var2. + (symbol/var/const parts may be omitted). If we are looking for an address, + find the cost of addressing this. */ + if (address_p) + return add_costs (cost, get_address_cost (symbol_present, var_present, + offset, ratio, + TYPE_MODE (TREE_TYPE (*use->op_p)), speed)); + + /* Otherwise estimate the costs for computing the expression. */ + aratio = ratio > 0 ? ratio : -ratio; + if (!symbol_present && !var_present && !offset) + { + if (ratio != 1) + cost.cost += multiply_by_cost (ratio, TYPE_MODE (ctype), speed); + + return cost; + } + + if (aratio != 1) + cost.cost += multiply_by_cost (aratio, TYPE_MODE (ctype), speed); + + n_sums = 1; + if (var_present + /* Symbol + offset should be compile-time computable. */ + && (symbol_present || offset)) + n_sums++; + + /* Having offset does not affect runtime cost in case it is added to + symbol, but it increases complexity. */ + if (offset) + cost.complexity++; + + cost.cost += n_sums * add_cost (TYPE_MODE (ctype), speed); + return cost; + +fallback: + { + /* Just get the expression, expand it and measure the cost. */ + tree comp = get_computation_at (data->current_loop, use, cand, at); + + if (!comp) + return infinite_cost; + + if (address_p) + comp = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (comp)), comp); + + return new_cost (computation_cost (comp, speed), 0); + } +} + +/* Determines the cost of the computation by that USE is expressed + from induction variable CAND. If ADDRESS_P is true, we just need + to create an address from it, otherwise we want to get it into + register. A set of invariants we depend on is stored in + DEPENDS_ON. */ + +static comp_cost +get_computation_cost (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand, + bool address_p, bitmap *depends_on) +{ + return get_computation_cost_at (data, + use, cand, address_p, depends_on, use->stmt); +} + +/* Determines cost of basing replacement of USE on CAND in a generic + expression. */ + +static bool +determine_use_iv_cost_generic (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + bitmap depends_on; + comp_cost cost; + + /* The simple case first -- if we need to express value of the preserved + original biv, the cost is 0. This also prevents us from counting the + cost of increment twice -- once at this use and once in the cost of + the candidate. */ + if (cand->pos == IP_ORIGINAL + && cand->incremented_at == use->stmt) + { + set_use_iv_cost (data, use, cand, zero_cost, NULL, NULL_TREE); + return true; + } + + cost = get_computation_cost (data, use, cand, false, &depends_on); + set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE); + + return !infinite_cost_p (cost); +} + +/* Determines cost of basing replacement of USE on CAND in an address. */ + +static bool +determine_use_iv_cost_address (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + bitmap depends_on; + comp_cost cost = get_computation_cost (data, use, cand, true, &depends_on); + + set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE); + + return !infinite_cost_p (cost); +} + +/* Computes value of candidate CAND at position AT in iteration NITER, and + stores it to VAL. */ + +static void +cand_value_at (struct loop *loop, struct iv_cand *cand, gimple at, tree niter, + aff_tree *val) +{ + aff_tree step, delta, nit; + struct iv *iv = cand->iv; + tree type = TREE_TYPE (iv->base); + tree steptype = type; + if (POINTER_TYPE_P (type)) + steptype = sizetype; + + tree_to_aff_combination (iv->step, steptype, &step); + tree_to_aff_combination (niter, TREE_TYPE (niter), &nit); + aff_combination_convert (&nit, steptype); + aff_combination_mult (&nit, &step, &delta); + if (stmt_after_increment (loop, cand, at)) + aff_combination_add (&delta, &step); + + tree_to_aff_combination (iv->base, type, val); + aff_combination_add (val, &delta); +} + +/* Returns period of induction variable iv. */ + +static tree +iv_period (struct iv *iv) +{ + tree step = iv->step, period, type; + tree pow2div; + + gcc_assert (step && TREE_CODE (step) == INTEGER_CST); + + /* Period of the iv is gcd (step, type range). Since type range is power + of two, it suffices to determine the maximum power of two that divides + step. */ + pow2div = num_ending_zeros (step); + type = unsigned_type_for (TREE_TYPE (step)); + + period = build_low_bits_mask (type, + (TYPE_PRECISION (type) + - tree_low_cst (pow2div, 1))); + + return period; +} + +/* Returns the comparison operator used when eliminating the iv USE. */ + +static enum tree_code +iv_elimination_compare (struct ivopts_data *data, struct iv_use *use) +{ + struct loop *loop = data->current_loop; + basic_block ex_bb; + edge exit; + + ex_bb = gimple_bb (use->stmt); + exit = EDGE_SUCC (ex_bb, 0); + if (flow_bb_inside_loop_p (loop, exit->dest)) + exit = EDGE_SUCC (ex_bb, 1); + + return (exit->flags & EDGE_TRUE_VALUE ? EQ_EXPR : NE_EXPR); +} + +/* Check whether it is possible to express the condition in USE by comparison + of candidate CAND. If so, store the value compared with to BOUND. */ + +static bool +may_eliminate_iv (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand, tree *bound) +{ + basic_block ex_bb; + edge exit; + tree nit, period; + struct loop *loop = data->current_loop; + aff_tree bnd; + + if (TREE_CODE (cand->iv->step) != INTEGER_CST) + return false; + + /* For now works only for exits that dominate the loop latch. + TODO: extend to other conditions inside loop body. */ + ex_bb = gimple_bb (use->stmt); + if (use->stmt != last_stmt (ex_bb) + || gimple_code (use->stmt) != GIMPLE_COND + || !dominated_by_p (CDI_DOMINATORS, loop->latch, ex_bb)) + return false; + + exit = EDGE_SUCC (ex_bb, 0); + if (flow_bb_inside_loop_p (loop, exit->dest)) + exit = EDGE_SUCC (ex_bb, 1); + if (flow_bb_inside_loop_p (loop, exit->dest)) + return false; + + nit = niter_for_exit (data, exit); + if (!nit) + return false; + + /* Determine whether we can use the variable to test the exit condition. + This is the case iff the period of the induction variable is greater + than the number of iterations for which the exit condition is true. */ + period = iv_period (cand->iv); + + /* If the number of iterations is constant, compare against it directly. */ + if (TREE_CODE (nit) == INTEGER_CST) + { + if (!tree_int_cst_lt (nit, period)) + return false; + } + + /* If not, and if this is the only possible exit of the loop, see whether + we can get a conservative estimate on the number of iterations of the + entire loop and compare against that instead. */ + else if (loop_only_exit_p (loop, exit)) + { + double_int period_value, max_niter; + if (!estimated_loop_iterations (loop, true, &max_niter)) + return false; + period_value = tree_to_double_int (period); + if (double_int_ucmp (max_niter, period_value) >= 0) + return false; + } + + /* Otherwise, punt. */ + else + return false; + + cand_value_at (loop, cand, use->stmt, nit, &bnd); + + *bound = aff_combination_to_tree (&bnd); + /* It is unlikely that computing the number of iterations using division + would be more profitable than keeping the original induction variable. */ + if (expression_expensive_p (*bound)) + return false; + return true; +} + +/* Determines cost of basing replacement of USE on CAND in a condition. */ + +static bool +determine_use_iv_cost_condition (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + tree bound = NULL_TREE; + struct iv *cmp_iv; + bitmap depends_on_elim = NULL, depends_on_express = NULL, depends_on; + comp_cost elim_cost, express_cost, cost; + bool ok; + + /* Only consider real candidates. */ + if (!cand->iv) + { + set_use_iv_cost (data, use, cand, infinite_cost, NULL, NULL_TREE); + return false; + } + + /* Try iv elimination. */ + if (may_eliminate_iv (data, use, cand, &bound)) + { + elim_cost = force_var_cost (data, bound, &depends_on_elim); + /* The bound is a loop invariant, so it will be only computed + once. */ + elim_cost.cost /= AVG_LOOP_NITER (data->current_loop); + } + else + elim_cost = infinite_cost; + + /* Try expressing the original giv. If it is compared with an invariant, + note that we cannot get rid of it. */ + ok = extract_cond_operands (data, use->stmt, NULL, NULL, NULL, &cmp_iv); + gcc_assert (ok); + + express_cost = get_computation_cost (data, use, cand, false, + &depends_on_express); + fd_ivopts_data = data; + walk_tree (&cmp_iv->base, find_depends, &depends_on_express, NULL); + + /* Choose the better approach, preferring the eliminated IV. */ + if (compare_costs (elim_cost, express_cost) <= 0) + { + cost = elim_cost; + depends_on = depends_on_elim; + depends_on_elim = NULL; + } + else + { + cost = express_cost; + depends_on = depends_on_express; + depends_on_express = NULL; + bound = NULL_TREE; + } + + set_use_iv_cost (data, use, cand, cost, depends_on, bound); + + if (depends_on_elim) + BITMAP_FREE (depends_on_elim); + if (depends_on_express) + BITMAP_FREE (depends_on_express); + + return !infinite_cost_p (cost); +} + +/* Determines cost of basing replacement of USE on CAND. Returns false + if USE cannot be based on CAND. */ + +static bool +determine_use_iv_cost (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + switch (use->type) + { + case USE_NONLINEAR_EXPR: + return determine_use_iv_cost_generic (data, use, cand); + + case USE_ADDRESS: + return determine_use_iv_cost_address (data, use, cand); + + case USE_COMPARE: + return determine_use_iv_cost_condition (data, use, cand); + + default: + gcc_unreachable (); + } +} + +/* Determines costs of basing the use of the iv on an iv candidate. */ + +static void +determine_use_iv_costs (struct ivopts_data *data) +{ + unsigned i, j; + struct iv_use *use; + struct iv_cand *cand; + bitmap to_clear = BITMAP_ALLOC (NULL); + + alloc_use_cost_map (data); + + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + + if (data->consider_all_candidates) + { + for (j = 0; j < n_iv_cands (data); j++) + { + cand = iv_cand (data, j); + determine_use_iv_cost (data, use, cand); + } + } + else + { + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (use->related_cands, 0, j, bi) + { + cand = iv_cand (data, j); + if (!determine_use_iv_cost (data, use, cand)) + bitmap_set_bit (to_clear, j); + } + + /* Remove the candidates for that the cost is infinite from + the list of related candidates. */ + bitmap_and_compl_into (use->related_cands, to_clear); + bitmap_clear (to_clear); + } + } + + BITMAP_FREE (to_clear); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Use-candidate costs:\n"); + + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + + fprintf (dump_file, "Use %d:\n", i); + fprintf (dump_file, " cand\tcost\tcompl.\tdepends on\n"); + for (j = 0; j < use->n_map_members; j++) + { + if (!use->cost_map[j].cand + || infinite_cost_p (use->cost_map[j].cost)) + continue; + + fprintf (dump_file, " %d\t%d\t%d\t", + use->cost_map[j].cand->id, + use->cost_map[j].cost.cost, + use->cost_map[j].cost.complexity); + if (use->cost_map[j].depends_on) + bitmap_print (dump_file, + use->cost_map[j].depends_on, "",""); + fprintf (dump_file, "\n"); + } + + fprintf (dump_file, "\n"); + } + fprintf (dump_file, "\n"); + } +} + +/* Determines cost of the candidate CAND. */ + +static void +determine_iv_cost (struct ivopts_data *data, struct iv_cand *cand) +{ + comp_cost cost_base; + unsigned cost, cost_step; + tree base; + + if (!cand->iv) + { + cand->cost = 0; + return; + } + + /* There are two costs associated with the candidate -- its increment + and its initialization. The second is almost negligible for any loop + that rolls enough, so we take it just very little into account. */ + + base = cand->iv->base; + cost_base = force_var_cost (data, base, NULL); + cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed); + + cost = cost_step + cost_base.cost / AVG_LOOP_NITER (current_loop); + + /* Prefer the original ivs unless we may gain something by replacing it. + The reason is to make debugging simpler; so this is not relevant for + artificial ivs created by other optimization passes. */ + if (cand->pos != IP_ORIGINAL + || DECL_ARTIFICIAL (SSA_NAME_VAR (cand->var_before))) + cost++; + + /* Prefer not to insert statements into latch unless there are some + already (so that we do not create unnecessary jumps). */ + if (cand->pos == IP_END + && empty_block_p (ip_end_pos (data->current_loop))) + cost++; + + cand->cost = cost; +} + +/* Determines costs of computation of the candidates. */ + +static void +determine_iv_costs (struct ivopts_data *data) +{ + unsigned i; + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Candidate costs:\n"); + fprintf (dump_file, " cand\tcost\n"); + } + + for (i = 0; i < n_iv_cands (data); i++) + { + struct iv_cand *cand = iv_cand (data, i); + + determine_iv_cost (data, cand); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, " %d\t%d\n", i, cand->cost); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\n"); +} + +/* Calculates cost for having SIZE induction variables. */ + +static unsigned +ivopts_global_cost_for_size (struct ivopts_data *data, unsigned size) +{ + /* We add size to the cost, so that we prefer eliminating ivs + if possible. */ + return size + estimate_reg_pressure_cost (size, data->regs_used, data->speed); +} + +/* For each size of the induction variable set determine the penalty. */ + +static void +determine_set_costs (struct ivopts_data *data) +{ + unsigned j, n; + gimple phi; + gimple_stmt_iterator psi; + tree op; + struct loop *loop = data->current_loop; + bitmap_iterator bi; + + /* We use the following model (definitely improvable, especially the + cost function -- TODO): + + We estimate the number of registers available (using MD data), name it A. + + We estimate the number of registers used by the loop, name it U. This + number is obtained as the number of loop phi nodes (not counting virtual + registers and bivs) + the number of variables from outside of the loop. + + We set a reserve R (free regs that are used for temporary computations, + etc.). For now the reserve is a constant 3. + + Let I be the number of induction variables. + + -- if U + I + R <= A, the cost is I * SMALL_COST (just not to encourage + make a lot of ivs without a reason). + -- if A - R < U + I <= A, the cost is I * PRES_COST + -- if U + I > A, the cost is I * PRES_COST and + number of uses * SPILL_COST * (U + I - A) / (U + I) is added. */ + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Global costs:\n"); + fprintf (dump_file, " target_avail_regs %d\n", target_avail_regs); + fprintf (dump_file, " target_reg_cost %d\n", target_reg_cost[data->speed]); + fprintf (dump_file, " target_spill_cost %d\n", target_spill_cost[data->speed]); + } + + n = 0; + for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) + { + phi = gsi_stmt (psi); + op = PHI_RESULT (phi); + + if (!is_gimple_reg (op)) + continue; + + if (get_iv (data, op)) + continue; + + n++; + } + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi) + { + struct version_info *info = ver_info (data, j); + + if (info->inv_id && info->has_nonlin_use) + n++; + } + + data->regs_used = n; + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, " regs_used %d\n", n); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " cost for size:\n"); + fprintf (dump_file, " ivs\tcost\n"); + for (j = 0; j <= 2 * target_avail_regs; j++) + fprintf (dump_file, " %d\t%d\n", j, + ivopts_global_cost_for_size (data, j)); + fprintf (dump_file, "\n"); + } +} + +/* Returns true if A is a cheaper cost pair than B. */ + +static bool +cheaper_cost_pair (struct cost_pair *a, struct cost_pair *b) +{ + int cmp; + + if (!a) + return false; + + if (!b) + return true; + + cmp = compare_costs (a->cost, b->cost); + if (cmp < 0) + return true; + + if (cmp > 0) + return false; + + /* In case the costs are the same, prefer the cheaper candidate. */ + if (a->cand->cost < b->cand->cost) + return true; + + return false; +} + +/* Computes the cost field of IVS structure. */ + +static void +iv_ca_recount_cost (struct ivopts_data *data, struct iv_ca *ivs) +{ + comp_cost cost = ivs->cand_use_cost; + cost.cost += ivs->cand_cost; + cost.cost += ivopts_global_cost_for_size (data, ivs->n_regs); + + ivs->cost = cost; +} + +/* Remove invariants in set INVS to set IVS. */ + +static void +iv_ca_set_remove_invariants (struct iv_ca *ivs, bitmap invs) +{ + bitmap_iterator bi; + unsigned iid; + + if (!invs) + return; + + EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi) + { + ivs->n_invariant_uses[iid]--; + if (ivs->n_invariant_uses[iid] == 0) + ivs->n_regs--; + } +} + +/* Set USE not to be expressed by any candidate in IVS. */ + +static void +iv_ca_set_no_cp (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_use *use) +{ + unsigned uid = use->id, cid; + struct cost_pair *cp; + + cp = ivs->cand_for_use[uid]; + if (!cp) + return; + cid = cp->cand->id; + + ivs->bad_uses++; + ivs->cand_for_use[uid] = NULL; + ivs->n_cand_uses[cid]--; + + if (ivs->n_cand_uses[cid] == 0) + { + bitmap_clear_bit (ivs->cands, cid); + /* Do not count the pseudocandidates. */ + if (cp->cand->iv) + ivs->n_regs--; + ivs->n_cands--; + ivs->cand_cost -= cp->cand->cost; + + iv_ca_set_remove_invariants (ivs, cp->cand->depends_on); + } + + ivs->cand_use_cost = sub_costs (ivs->cand_use_cost, cp->cost); + + iv_ca_set_remove_invariants (ivs, cp->depends_on); + iv_ca_recount_cost (data, ivs); +} + +/* Add invariants in set INVS to set IVS. */ + +static void +iv_ca_set_add_invariants (struct iv_ca *ivs, bitmap invs) +{ + bitmap_iterator bi; + unsigned iid; + + if (!invs) + return; + + EXECUTE_IF_SET_IN_BITMAP (invs, 0, iid, bi) + { + ivs->n_invariant_uses[iid]++; + if (ivs->n_invariant_uses[iid] == 1) + ivs->n_regs++; + } +} + +/* Set cost pair for USE in set IVS to CP. */ + +static void +iv_ca_set_cp (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_use *use, struct cost_pair *cp) +{ + unsigned uid = use->id, cid; + + if (ivs->cand_for_use[uid] == cp) + return; + + if (ivs->cand_for_use[uid]) + iv_ca_set_no_cp (data, ivs, use); + + if (cp) + { + cid = cp->cand->id; + + ivs->bad_uses--; + ivs->cand_for_use[uid] = cp; + ivs->n_cand_uses[cid]++; + if (ivs->n_cand_uses[cid] == 1) + { + bitmap_set_bit (ivs->cands, cid); + /* Do not count the pseudocandidates. */ + if (cp->cand->iv) + ivs->n_regs++; + ivs->n_cands++; + ivs->cand_cost += cp->cand->cost; + + iv_ca_set_add_invariants (ivs, cp->cand->depends_on); + } + + ivs->cand_use_cost = add_costs (ivs->cand_use_cost, cp->cost); + iv_ca_set_add_invariants (ivs, cp->depends_on); + iv_ca_recount_cost (data, ivs); + } +} + +/* Extend set IVS by expressing USE by some of the candidates in it + if possible. */ + +static void +iv_ca_add_use (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_use *use) +{ + struct cost_pair *best_cp = NULL, *cp; + bitmap_iterator bi; + unsigned i; + + gcc_assert (ivs->upto >= use->id); + + if (ivs->upto == use->id) + { + ivs->upto++; + ivs->bad_uses++; + } + + EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi) + { + cp = get_use_iv_cost (data, use, iv_cand (data, i)); + + if (cheaper_cost_pair (cp, best_cp)) + best_cp = cp; + } + + iv_ca_set_cp (data, ivs, use, best_cp); +} + +/* Get cost for assignment IVS. */ + +static comp_cost +iv_ca_cost (struct iv_ca *ivs) +{ + /* This was a conditional expression but it triggered a bug in + Sun C 5.5. */ + if (ivs->bad_uses) + return infinite_cost; + else + return ivs->cost; +} + +/* Returns true if all dependences of CP are among invariants in IVS. */ + +static bool +iv_ca_has_deps (struct iv_ca *ivs, struct cost_pair *cp) +{ + unsigned i; + bitmap_iterator bi; + + if (!cp->depends_on) + return true; + + EXECUTE_IF_SET_IN_BITMAP (cp->depends_on, 0, i, bi) + { + if (ivs->n_invariant_uses[i] == 0) + return false; + } + + return true; +} + +/* Creates change of expressing USE by NEW_CP instead of OLD_CP and chains + it before NEXT_CHANGE. */ + +static struct iv_ca_delta * +iv_ca_delta_add (struct iv_use *use, struct cost_pair *old_cp, + struct cost_pair *new_cp, struct iv_ca_delta *next_change) +{ + struct iv_ca_delta *change = XNEW (struct iv_ca_delta); + + change->use = use; + change->old_cp = old_cp; + change->new_cp = new_cp; + change->next_change = next_change; + + return change; +} + +/* Joins two lists of changes L1 and L2. Destructive -- old lists + are rewritten. */ + +static struct iv_ca_delta * +iv_ca_delta_join (struct iv_ca_delta *l1, struct iv_ca_delta *l2) +{ + struct iv_ca_delta *last; + + if (!l2) + return l1; + + if (!l1) + return l2; + + for (last = l1; last->next_change; last = last->next_change) + continue; + last->next_change = l2; + + return l1; +} + +/* Returns candidate by that USE is expressed in IVS. */ + +static struct cost_pair * +iv_ca_cand_for_use (struct iv_ca *ivs, struct iv_use *use) +{ + return ivs->cand_for_use[use->id]; +} + +/* Reverse the list of changes DELTA, forming the inverse to it. */ + +static struct iv_ca_delta * +iv_ca_delta_reverse (struct iv_ca_delta *delta) +{ + struct iv_ca_delta *act, *next, *prev = NULL; + struct cost_pair *tmp; + + for (act = delta; act; act = next) + { + next = act->next_change; + act->next_change = prev; + prev = act; + + tmp = act->old_cp; + act->old_cp = act->new_cp; + act->new_cp = tmp; + } + + return prev; +} + +/* Commit changes in DELTA to IVS. If FORWARD is false, the changes are + reverted instead. */ + +static void +iv_ca_delta_commit (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_ca_delta *delta, bool forward) +{ + struct cost_pair *from, *to; + struct iv_ca_delta *act; + + if (!forward) + delta = iv_ca_delta_reverse (delta); + + for (act = delta; act; act = act->next_change) + { + from = act->old_cp; + to = act->new_cp; + gcc_assert (iv_ca_cand_for_use (ivs, act->use) == from); + iv_ca_set_cp (data, ivs, act->use, to); + } + + if (!forward) + iv_ca_delta_reverse (delta); +} + +/* Returns true if CAND is used in IVS. */ + +static bool +iv_ca_cand_used_p (struct iv_ca *ivs, struct iv_cand *cand) +{ + return ivs->n_cand_uses[cand->id] > 0; +} + +/* Returns number of induction variable candidates in the set IVS. */ + +static unsigned +iv_ca_n_cands (struct iv_ca *ivs) +{ + return ivs->n_cands; +} + +/* Free the list of changes DELTA. */ + +static void +iv_ca_delta_free (struct iv_ca_delta **delta) +{ + struct iv_ca_delta *act, *next; + + for (act = *delta; act; act = next) + { + next = act->next_change; + free (act); + } + + *delta = NULL; +} + +/* Allocates new iv candidates assignment. */ + +static struct iv_ca * +iv_ca_new (struct ivopts_data *data) +{ + struct iv_ca *nw = XNEW (struct iv_ca); + + nw->upto = 0; + nw->bad_uses = 0; + nw->cand_for_use = XCNEWVEC (struct cost_pair *, n_iv_uses (data)); + nw->n_cand_uses = XCNEWVEC (unsigned, n_iv_cands (data)); + nw->cands = BITMAP_ALLOC (NULL); + nw->n_cands = 0; + nw->n_regs = 0; + nw->cand_use_cost = zero_cost; + nw->cand_cost = 0; + nw->n_invariant_uses = XCNEWVEC (unsigned, data->max_inv_id + 1); + nw->cost = zero_cost; + + return nw; +} + +/* Free memory occupied by the set IVS. */ + +static void +iv_ca_free (struct iv_ca **ivs) +{ + free ((*ivs)->cand_for_use); + free ((*ivs)->n_cand_uses); + BITMAP_FREE ((*ivs)->cands); + free ((*ivs)->n_invariant_uses); + free (*ivs); + *ivs = NULL; +} + +/* Dumps IVS to FILE. */ + +static void +iv_ca_dump (struct ivopts_data *data, FILE *file, struct iv_ca *ivs) +{ + const char *pref = " invariants "; + unsigned i; + comp_cost cost = iv_ca_cost (ivs); + + fprintf (file, " cost %d (complexity %d)\n", cost.cost, cost.complexity); + bitmap_print (file, ivs->cands, " candidates ","\n"); + + for (i = 1; i <= data->max_inv_id; i++) + if (ivs->n_invariant_uses[i]) + { + fprintf (file, "%s%d", pref, i); + pref = ", "; + } + fprintf (file, "\n"); +} + +/* Try changing candidate in IVS to CAND for each use. Return cost of the + new set, and store differences in DELTA. Number of induction variables + in the new set is stored to N_IVS. */ + +static comp_cost +iv_ca_extend (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_cand *cand, struct iv_ca_delta **delta, + unsigned *n_ivs) +{ + unsigned i; + comp_cost cost; + struct iv_use *use; + struct cost_pair *old_cp, *new_cp; + + *delta = NULL; + for (i = 0; i < ivs->upto; i++) + { + use = iv_use (data, i); + old_cp = iv_ca_cand_for_use (ivs, use); + + if (old_cp + && old_cp->cand == cand) + continue; + + new_cp = get_use_iv_cost (data, use, cand); + if (!new_cp) + continue; + + if (!iv_ca_has_deps (ivs, new_cp)) + continue; + + if (!cheaper_cost_pair (new_cp, old_cp)) + continue; + + *delta = iv_ca_delta_add (use, old_cp, new_cp, *delta); + } + + iv_ca_delta_commit (data, ivs, *delta, true); + cost = iv_ca_cost (ivs); + if (n_ivs) + *n_ivs = iv_ca_n_cands (ivs); + iv_ca_delta_commit (data, ivs, *delta, false); + + return cost; +} + +/* Try narrowing set IVS by removing CAND. Return the cost of + the new set and store the differences in DELTA. */ + +static comp_cost +iv_ca_narrow (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_cand *cand, struct iv_ca_delta **delta) +{ + unsigned i, ci; + struct iv_use *use; + struct cost_pair *old_cp, *new_cp, *cp; + bitmap_iterator bi; + struct iv_cand *cnd; + comp_cost cost; + + *delta = NULL; + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + + old_cp = iv_ca_cand_for_use (ivs, use); + if (old_cp->cand != cand) + continue; + + new_cp = NULL; + + if (data->consider_all_candidates) + { + EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, ci, bi) + { + if (ci == cand->id) + continue; + + cnd = iv_cand (data, ci); + + cp = get_use_iv_cost (data, use, cnd); + if (!cp) + continue; + if (!iv_ca_has_deps (ivs, cp)) + continue; + + if (!cheaper_cost_pair (cp, new_cp)) + continue; + + new_cp = cp; + } + } + else + { + EXECUTE_IF_AND_IN_BITMAP (use->related_cands, ivs->cands, 0, ci, bi) + { + if (ci == cand->id) + continue; + + cnd = iv_cand (data, ci); + + cp = get_use_iv_cost (data, use, cnd); + if (!cp) + continue; + if (!iv_ca_has_deps (ivs, cp)) + continue; + + if (!cheaper_cost_pair (cp, new_cp)) + continue; + + new_cp = cp; + } + } + + if (!new_cp) + { + iv_ca_delta_free (delta); + return infinite_cost; + } + + *delta = iv_ca_delta_add (use, old_cp, new_cp, *delta); + } + + iv_ca_delta_commit (data, ivs, *delta, true); + cost = iv_ca_cost (ivs); + iv_ca_delta_commit (data, ivs, *delta, false); + + return cost; +} + +/* Try optimizing the set of candidates IVS by removing candidates different + from to EXCEPT_CAND from it. Return cost of the new set, and store + differences in DELTA. */ + +static comp_cost +iv_ca_prune (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_cand *except_cand, struct iv_ca_delta **delta) +{ + bitmap_iterator bi; + struct iv_ca_delta *act_delta, *best_delta; + unsigned i; + comp_cost best_cost, acost; + struct iv_cand *cand; + + best_delta = NULL; + best_cost = iv_ca_cost (ivs); + + EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi) + { + cand = iv_cand (data, i); + + if (cand == except_cand) + continue; + + acost = iv_ca_narrow (data, ivs, cand, &act_delta); + + if (compare_costs (acost, best_cost) < 0) + { + best_cost = acost; + iv_ca_delta_free (&best_delta); + best_delta = act_delta; + } + else + iv_ca_delta_free (&act_delta); + } + + if (!best_delta) + { + *delta = NULL; + return best_cost; + } + + /* Recurse to possibly remove other unnecessary ivs. */ + iv_ca_delta_commit (data, ivs, best_delta, true); + best_cost = iv_ca_prune (data, ivs, except_cand, delta); + iv_ca_delta_commit (data, ivs, best_delta, false); + *delta = iv_ca_delta_join (best_delta, *delta); + return best_cost; +} + +/* Tries to extend the sets IVS in the best possible way in order + to express the USE. */ + +static bool +try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, + struct iv_use *use) +{ + comp_cost best_cost, act_cost; + unsigned i; + bitmap_iterator bi; + struct iv_cand *cand; + struct iv_ca_delta *best_delta = NULL, *act_delta; + struct cost_pair *cp; + + iv_ca_add_use (data, ivs, use); + best_cost = iv_ca_cost (ivs); + + cp = iv_ca_cand_for_use (ivs, use); + if (cp) + { + best_delta = iv_ca_delta_add (use, NULL, cp, NULL); + iv_ca_set_no_cp (data, ivs, use); + } + + /* First try important candidates not based on any memory object. Only if + this fails, try the specific ones. Rationale -- in loops with many + variables the best choice often is to use just one generic biv. If we + added here many ivs specific to the uses, the optimization algorithm later + would be likely to get stuck in a local minimum, thus causing us to create + too many ivs. The approach from few ivs to more seems more likely to be + successful -- starting from few ivs, replacing an expensive use by a + specific iv should always be a win. */ + EXECUTE_IF_SET_IN_BITMAP (data->important_candidates, 0, i, bi) + { + cand = iv_cand (data, i); + + if (cand->iv->base_object != NULL_TREE) + continue; + + if (iv_ca_cand_used_p (ivs, cand)) + continue; + + cp = get_use_iv_cost (data, use, cand); + if (!cp) + continue; + + iv_ca_set_cp (data, ivs, use, cp); + act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL); + iv_ca_set_no_cp (data, ivs, use); + act_delta = iv_ca_delta_add (use, NULL, cp, act_delta); + + if (compare_costs (act_cost, best_cost) < 0) + { + best_cost = act_cost; + + iv_ca_delta_free (&best_delta); + best_delta = act_delta; + } + else + iv_ca_delta_free (&act_delta); + } + + if (infinite_cost_p (best_cost)) + { + for (i = 0; i < use->n_map_members; i++) + { + cp = use->cost_map + i; + cand = cp->cand; + if (!cand) + continue; + + /* Already tried this. */ + if (cand->important && cand->iv->base_object == NULL_TREE) + continue; + + if (iv_ca_cand_used_p (ivs, cand)) + continue; + + act_delta = NULL; + iv_ca_set_cp (data, ivs, use, cp); + act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL); + iv_ca_set_no_cp (data, ivs, use); + act_delta = iv_ca_delta_add (use, iv_ca_cand_for_use (ivs, use), + cp, act_delta); + + if (compare_costs (act_cost, best_cost) < 0) + { + best_cost = act_cost; + + if (best_delta) + iv_ca_delta_free (&best_delta); + best_delta = act_delta; + } + else + iv_ca_delta_free (&act_delta); + } + } + + iv_ca_delta_commit (data, ivs, best_delta, true); + iv_ca_delta_free (&best_delta); + + return !infinite_cost_p (best_cost); +} + +/* Finds an initial assignment of candidates to uses. */ + +static struct iv_ca * +get_initial_solution (struct ivopts_data *data) +{ + struct iv_ca *ivs = iv_ca_new (data); + unsigned i; + + for (i = 0; i < n_iv_uses (data); i++) + if (!try_add_cand_for (data, ivs, iv_use (data, i))) + { + iv_ca_free (&ivs); + return NULL; + } + + return ivs; +} + +/* Tries to improve set of induction variables IVS. */ + +static bool +try_improve_iv_set (struct ivopts_data *data, struct iv_ca *ivs) +{ + unsigned i, n_ivs; + comp_cost acost, best_cost = iv_ca_cost (ivs); + struct iv_ca_delta *best_delta = NULL, *act_delta, *tmp_delta; + struct iv_cand *cand; + + /* Try extending the set of induction variables by one. */ + for (i = 0; i < n_iv_cands (data); i++) + { + cand = iv_cand (data, i); + + if (iv_ca_cand_used_p (ivs, cand)) + continue; + + acost = iv_ca_extend (data, ivs, cand, &act_delta, &n_ivs); + if (!act_delta) + continue; + + /* If we successfully added the candidate and the set is small enough, + try optimizing it by removing other candidates. */ + if (n_ivs <= ALWAYS_PRUNE_CAND_SET_BOUND) + { + iv_ca_delta_commit (data, ivs, act_delta, true); + acost = iv_ca_prune (data, ivs, cand, &tmp_delta); + iv_ca_delta_commit (data, ivs, act_delta, false); + act_delta = iv_ca_delta_join (act_delta, tmp_delta); + } + + if (compare_costs (acost, best_cost) < 0) + { + best_cost = acost; + iv_ca_delta_free (&best_delta); + best_delta = act_delta; + } + else + iv_ca_delta_free (&act_delta); + } + + if (!best_delta) + { + /* Try removing the candidates from the set instead. */ + best_cost = iv_ca_prune (data, ivs, NULL, &best_delta); + + /* Nothing more we can do. */ + if (!best_delta) + return false; + } + + iv_ca_delta_commit (data, ivs, best_delta, true); + gcc_assert (compare_costs (best_cost, iv_ca_cost (ivs)) == 0); + iv_ca_delta_free (&best_delta); + return true; +} + +/* Attempts to find the optimal set of induction variables. We do simple + greedy heuristic -- we try to replace at most one candidate in the selected + solution and remove the unused ivs while this improves the cost. */ + +static struct iv_ca * +find_optimal_iv_set (struct ivopts_data *data) +{ + unsigned i; + struct iv_ca *set; + struct iv_use *use; + + /* Get the initial solution. */ + set = get_initial_solution (data); + if (!set) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Unable to substitute for ivs, failed.\n"); + return NULL; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Initial set of candidates:\n"); + iv_ca_dump (data, dump_file, set); + } + + while (try_improve_iv_set (data, set)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Improved to:\n"); + iv_ca_dump (data, dump_file, set); + } + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + comp_cost cost = iv_ca_cost (set); + fprintf (dump_file, "Final cost %d (complexity %d)\n\n", cost.cost, cost.complexity); + } + + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + use->selected = iv_ca_cand_for_use (set, use)->cand; + } + + return set; +} + +/* Creates a new induction variable corresponding to CAND. */ + +static void +create_new_iv (struct ivopts_data *data, struct iv_cand *cand) +{ + gimple_stmt_iterator incr_pos; + tree base; + bool after = false; + + if (!cand->iv) + return; + + switch (cand->pos) + { + case IP_NORMAL: + incr_pos = gsi_last_bb (ip_normal_pos (data->current_loop)); + break; + + case IP_END: + incr_pos = gsi_last_bb (ip_end_pos (data->current_loop)); + after = true; + break; + + case IP_ORIGINAL: + /* Mark that the iv is preserved. */ + name_info (data, cand->var_before)->preserve_biv = true; + name_info (data, cand->var_after)->preserve_biv = true; + + /* Rewrite the increment so that it uses var_before directly. */ + find_interesting_uses_op (data, cand->var_after)->selected = cand; + + return; + } + + gimple_add_tmp_var (cand->var_before); + add_referenced_var (cand->var_before); + + base = unshare_expr (cand->iv->base); + + create_iv (base, unshare_expr (cand->iv->step), + cand->var_before, data->current_loop, + &incr_pos, after, &cand->var_before, &cand->var_after); +} + +/* Creates new induction variables described in SET. */ + +static void +create_new_ivs (struct ivopts_data *data, struct iv_ca *set) +{ + unsigned i; + struct iv_cand *cand; + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (set->cands, 0, i, bi) + { + cand = iv_cand (data, i); + create_new_iv (data, cand); + } +} + +/* Returns the phi-node in BB with result RESULT. */ + +static gimple +get_phi_with_result (basic_block bb, tree result) +{ + gimple_stmt_iterator i = gsi_start_phis (bb); + + for (; !gsi_end_p (i); gsi_next (&i)) + if (gimple_phi_result (gsi_stmt (i)) == result) + return gsi_stmt (i); + + gcc_unreachable (); + return NULL; +} + + +/* Removes statement STMT (real or a phi node). If INCLUDING_DEFINED_NAME + is true, remove also the ssa name defined by the statement. */ + +static void +remove_statement (gimple stmt, bool including_defined_name) +{ + if (gimple_code (stmt) == GIMPLE_PHI) + { + gimple bb_phi = get_phi_with_result (gimple_bb (stmt), + gimple_phi_result (stmt)); + gimple_stmt_iterator bsi = gsi_for_stmt (bb_phi); + remove_phi_node (&bsi, including_defined_name); + } + else + { + gimple_stmt_iterator bsi = gsi_for_stmt (stmt); + gsi_remove (&bsi, true); + release_defs (stmt); + } +} + +/* Rewrites USE (definition of iv used in a nonlinear expression) + using candidate CAND. */ + +static void +rewrite_use_nonlinear_expr (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + tree comp; + tree op, tgt; + gimple ass; + gimple_stmt_iterator bsi; + + /* An important special case -- if we are asked to express value of + the original iv by itself, just exit; there is no need to + introduce a new computation (that might also need casting the + variable to unsigned and back). */ + if (cand->pos == IP_ORIGINAL + && cand->incremented_at == use->stmt) + { + tree step, ctype, utype; + enum tree_code incr_code = PLUS_EXPR, old_code; + + gcc_assert (is_gimple_assign (use->stmt)); + gcc_assert (gimple_assign_lhs (use->stmt) == cand->var_after); + + step = cand->iv->step; + ctype = TREE_TYPE (step); + utype = TREE_TYPE (cand->var_after); + if (TREE_CODE (step) == NEGATE_EXPR) + { + incr_code = MINUS_EXPR; + step = TREE_OPERAND (step, 0); + } + + /* Check whether we may leave the computation unchanged. + This is the case only if it does not rely on other + computations in the loop -- otherwise, the computation + we rely upon may be removed in remove_unused_ivs, + thus leading to ICE. */ + old_code = gimple_assign_rhs_code (use->stmt); + if (old_code == PLUS_EXPR + || old_code == MINUS_EXPR + || old_code == POINTER_PLUS_EXPR) + { + if (gimple_assign_rhs1 (use->stmt) == cand->var_before) + op = gimple_assign_rhs2 (use->stmt); + else if (old_code != MINUS_EXPR + && gimple_assign_rhs2 (use->stmt) == cand->var_before) + op = gimple_assign_rhs1 (use->stmt); + else + op = NULL_TREE; + } + else + op = NULL_TREE; + + if (op + && (TREE_CODE (op) == INTEGER_CST + || operand_equal_p (op, step, 0))) + return; + + /* Otherwise, add the necessary computations to express + the iv. */ + op = fold_convert (ctype, cand->var_before); + comp = fold_convert (utype, + build2 (incr_code, ctype, op, + unshare_expr (step))); + } + else + { + comp = get_computation (data->current_loop, use, cand); + gcc_assert (comp != NULL_TREE); + } + + switch (gimple_code (use->stmt)) + { + case GIMPLE_PHI: + tgt = PHI_RESULT (use->stmt); + + /* If we should keep the biv, do not replace it. */ + if (name_info (data, tgt)->preserve_biv) + return; + + bsi = gsi_after_labels (gimple_bb (use->stmt)); + break; + + case GIMPLE_ASSIGN: + tgt = gimple_assign_lhs (use->stmt); + bsi = gsi_for_stmt (use->stmt); + break; + + default: + gcc_unreachable (); + } + + op = force_gimple_operand_gsi (&bsi, comp, false, SSA_NAME_VAR (tgt), + true, GSI_SAME_STMT); + + if (gimple_code (use->stmt) == GIMPLE_PHI) + { + ass = gimple_build_assign (tgt, op); + gsi_insert_before (&bsi, ass, GSI_SAME_STMT); + remove_statement (use->stmt, false); + } + else + { + gimple_assign_set_rhs_from_tree (&bsi, op); + use->stmt = gsi_stmt (bsi); + } +} + +/* Replaces ssa name in index IDX by its basic variable. Callback for + for_each_index. */ + +static bool +idx_remove_ssa_names (tree base, tree *idx, + void *data ATTRIBUTE_UNUSED) +{ + tree *op; + + if (TREE_CODE (*idx) == SSA_NAME) + *idx = SSA_NAME_VAR (*idx); + + if (TREE_CODE (base) == ARRAY_REF || TREE_CODE (base) == ARRAY_RANGE_REF) + { + op = &TREE_OPERAND (base, 2); + if (*op + && TREE_CODE (*op) == SSA_NAME) + *op = SSA_NAME_VAR (*op); + op = &TREE_OPERAND (base, 3); + if (*op + && TREE_CODE (*op) == SSA_NAME) + *op = SSA_NAME_VAR (*op); + } + + return true; +} + +/* Unshares REF and replaces ssa names inside it by their basic variables. */ + +static tree +unshare_and_remove_ssa_names (tree ref) +{ + ref = unshare_expr (ref); + for_each_index (&ref, idx_remove_ssa_names, NULL); + + return ref; +} + +/* Extract the alias analysis info for the memory reference REF. There are + several ways how this information may be stored and what precisely is + its semantics depending on the type of the reference, but there always is + somewhere hidden one _DECL node that is used to determine the set of + virtual operands for the reference. The code below deciphers this jungle + and extracts this single useful piece of information. */ + +static tree +get_ref_tag (tree ref, tree orig) +{ + tree var = get_base_address (ref); + tree aref = NULL_TREE, tag, sv; + HOST_WIDE_INT offset, size, maxsize; + + for (sv = orig; handled_component_p (sv); sv = TREE_OPERAND (sv, 0)) + { + aref = get_ref_base_and_extent (sv, &offset, &size, &maxsize); + if (ref) + break; + } + + if (!var) + return NULL_TREE; + + if (TREE_CODE (var) == INDIRECT_REF) + { + /* If the base is a dereference of a pointer, first check its name memory + tag. If it does not have one, use its symbol memory tag. */ + var = TREE_OPERAND (var, 0); + if (TREE_CODE (var) != SSA_NAME) + return NULL_TREE; + + if (SSA_NAME_PTR_INFO (var)) + { + tag = SSA_NAME_PTR_INFO (var)->name_mem_tag; + if (tag) + return tag; + } + + var = SSA_NAME_VAR (var); + tag = symbol_mem_tag (var); + gcc_assert (tag != NULL_TREE); + return tag; + } + else + { + if (!DECL_P (var)) + return NULL_TREE; + + tag = symbol_mem_tag (var); + if (tag) + return tag; + + return var; + } +} + +/* Copies the reference information from OLD_REF to NEW_REF. */ + +static void +copy_ref_info (tree new_ref, tree old_ref) +{ + if (TREE_CODE (old_ref) == TARGET_MEM_REF) + copy_mem_ref_info (new_ref, old_ref); + else + { + TMR_ORIGINAL (new_ref) = unshare_and_remove_ssa_names (old_ref); + TMR_TAG (new_ref) = get_ref_tag (old_ref, TMR_ORIGINAL (new_ref)); + } +} + +/* Rewrites USE (address that is an iv) using candidate CAND. */ + +static void +rewrite_use_address (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + aff_tree aff; + gimple_stmt_iterator bsi = gsi_for_stmt (use->stmt); + tree ref; + bool ok; + + ok = get_computation_aff (data->current_loop, use, cand, use->stmt, &aff); + gcc_assert (ok); + unshare_aff_combination (&aff); + + ref = create_mem_ref (&bsi, TREE_TYPE (*use->op_p), &aff, data->speed); + copy_ref_info (ref, *use->op_p); + *use->op_p = ref; +} + +/* Rewrites USE (the condition such that one of the arguments is an iv) using + candidate CAND. */ + +static void +rewrite_use_compare (struct ivopts_data *data, + struct iv_use *use, struct iv_cand *cand) +{ + tree comp, *var_p, op, bound; + gimple_stmt_iterator bsi = gsi_for_stmt (use->stmt); + enum tree_code compare; + struct cost_pair *cp = get_use_iv_cost (data, use, cand); + bool ok; + + bound = cp->value; + if (bound) + { + tree var = var_at_stmt (data->current_loop, cand, use->stmt); + tree var_type = TREE_TYPE (var); + gimple_seq stmts; + + compare = iv_elimination_compare (data, use); + bound = unshare_expr (fold_convert (var_type, bound)); + op = force_gimple_operand (bound, &stmts, true, NULL_TREE); + if (stmts) + gsi_insert_seq_on_edge_immediate ( + loop_preheader_edge (data->current_loop), + stmts); + + gimple_cond_set_lhs (use->stmt, var); + gimple_cond_set_code (use->stmt, compare); + gimple_cond_set_rhs (use->stmt, op); + return; + } + + /* The induction variable elimination failed; just express the original + giv. */ + comp = get_computation (data->current_loop, use, cand); + gcc_assert (comp != NULL_TREE); + + ok = extract_cond_operands (data, use->stmt, &var_p, NULL, NULL, NULL); + gcc_assert (ok); + + *var_p = force_gimple_operand_gsi (&bsi, comp, true, SSA_NAME_VAR (*var_p), + true, GSI_SAME_STMT); +} + +/* Rewrites USE using candidate CAND. */ + +static void +rewrite_use (struct ivopts_data *data, struct iv_use *use, struct iv_cand *cand) +{ + push_stmt_changes (&use->stmt); + + switch (use->type) + { + case USE_NONLINEAR_EXPR: + rewrite_use_nonlinear_expr (data, use, cand); + break; + + case USE_ADDRESS: + rewrite_use_address (data, use, cand); + break; + + case USE_COMPARE: + rewrite_use_compare (data, use, cand); + break; + + default: + gcc_unreachable (); + } + + pop_stmt_changes (&use->stmt); +} + +/* Rewrite the uses using the selected induction variables. */ + +static void +rewrite_uses (struct ivopts_data *data) +{ + unsigned i; + struct iv_cand *cand; + struct iv_use *use; + + for (i = 0; i < n_iv_uses (data); i++) + { + use = iv_use (data, i); + cand = use->selected; + gcc_assert (cand); + + rewrite_use (data, use, cand); + } +} + +/* Removes the ivs that are not used after rewriting. */ + +static void +remove_unused_ivs (struct ivopts_data *data) +{ + unsigned j; + bitmap_iterator bi; + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, j, bi) + { + struct version_info *info; + + info = ver_info (data, j); + if (info->iv + && !integer_zerop (info->iv->step) + && !info->inv_id + && !info->iv->have_use_for + && !info->preserve_biv) + remove_statement (SSA_NAME_DEF_STMT (info->iv->ssa_name), true); + } +} + +/* Frees data allocated by the optimization of a single loop. */ + +static void +free_loop_data (struct ivopts_data *data) +{ + unsigned i, j; + bitmap_iterator bi; + tree obj; + + if (data->niters) + { + pointer_map_destroy (data->niters); + data->niters = NULL; + } + + EXECUTE_IF_SET_IN_BITMAP (data->relevant, 0, i, bi) + { + struct version_info *info; + + info = ver_info (data, i); + if (info->iv) + free (info->iv); + info->iv = NULL; + info->has_nonlin_use = false; + info->preserve_biv = false; + info->inv_id = 0; + } + bitmap_clear (data->relevant); + bitmap_clear (data->important_candidates); + + for (i = 0; i < n_iv_uses (data); i++) + { + struct iv_use *use = iv_use (data, i); + + free (use->iv); + BITMAP_FREE (use->related_cands); + for (j = 0; j < use->n_map_members; j++) + if (use->cost_map[j].depends_on) + BITMAP_FREE (use->cost_map[j].depends_on); + free (use->cost_map); + free (use); + } + VEC_truncate (iv_use_p, data->iv_uses, 0); + + for (i = 0; i < n_iv_cands (data); i++) + { + struct iv_cand *cand = iv_cand (data, i); + + if (cand->iv) + free (cand->iv); + if (cand->depends_on) + BITMAP_FREE (cand->depends_on); + free (cand); + } + VEC_truncate (iv_cand_p, data->iv_candidates, 0); + + if (data->version_info_size < num_ssa_names) + { + data->version_info_size = 2 * num_ssa_names; + free (data->version_info); + data->version_info = XCNEWVEC (struct version_info, data->version_info_size); + } + + data->max_inv_id = 0; + + for (i = 0; VEC_iterate (tree, decl_rtl_to_reset, i, obj); i++) + SET_DECL_RTL (obj, NULL_RTX); + + VEC_truncate (tree, decl_rtl_to_reset, 0); +} + +/* Finalizes data structures used by the iv optimization pass. LOOPS is the + loop tree. */ + +static void +tree_ssa_iv_optimize_finalize (struct ivopts_data *data) +{ + free_loop_data (data); + free (data->version_info); + BITMAP_FREE (data->relevant); + BITMAP_FREE (data->important_candidates); + + VEC_free (tree, heap, decl_rtl_to_reset); + VEC_free (iv_use_p, heap, data->iv_uses); + VEC_free (iv_cand_p, heap, data->iv_candidates); +} + +/* Optimizes the LOOP. Returns true if anything changed. */ + +static bool +tree_ssa_iv_optimize_loop (struct ivopts_data *data, struct loop *loop) +{ + bool changed = false; + struct iv_ca *iv_ca; + edge exit; + + gcc_assert (!data->niters); + data->current_loop = loop; + data->speed = optimize_loop_for_speed_p (loop); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Processing loop %d\n", loop->num); + + exit = single_dom_exit (loop); + if (exit) + { + fprintf (dump_file, " single exit %d -> %d, exit condition ", + exit->src->index, exit->dest->index); + print_gimple_stmt (dump_file, last_stmt (exit->src), 0, TDF_SLIM); + fprintf (dump_file, "\n"); + } + + fprintf (dump_file, "\n"); + } + + /* For each ssa name determines whether it behaves as an induction variable + in some loop. */ + if (!find_induction_variables (data)) + goto finish; + + /* Finds interesting uses (item 1). */ + find_interesting_uses (data); + if (n_iv_uses (data) > MAX_CONSIDERED_USES) + goto finish; + + /* Finds candidates for the induction variables (item 2). */ + find_iv_candidates (data); + + /* Calculates the costs (item 3, part 1). */ + determine_use_iv_costs (data); + determine_iv_costs (data); + determine_set_costs (data); + + /* Find the optimal set of induction variables (item 3, part 2). */ + iv_ca = find_optimal_iv_set (data); + if (!iv_ca) + goto finish; + changed = true; + + /* Create the new induction variables (item 4, part 1). */ + create_new_ivs (data, iv_ca); + iv_ca_free (&iv_ca); + + /* Rewrite the uses (item 4, part 2). */ + rewrite_uses (data); + + /* Remove the ivs that are unused after rewriting. */ + remove_unused_ivs (data); + + /* We have changed the structure of induction variables; it might happen + that definitions in the scev database refer to some of them that were + eliminated. */ + scev_reset (); + +finish: + free_loop_data (data); + + return changed; +} + +/* Main entry point. Optimizes induction variables in loops. */ + +void +tree_ssa_iv_optimize (void) +{ + struct loop *loop; + struct ivopts_data data; + loop_iterator li; + + tree_ssa_iv_optimize_init (&data); + + /* Optimize the loops starting with the innermost ones. */ + FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + flow_loop_dump (loop, dump_file, NULL, 1); + + tree_ssa_iv_optimize_loop (&data, loop); + } + + tree_ssa_iv_optimize_finalize (&data); +}