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Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/tree-ssa-loop-ivopts.c')
| -rw-r--r-- | gcc-4.2.1-5666.3/gcc/tree-ssa-loop-ivopts.c | 5913 |
1 files changed, 0 insertions, 5913 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/tree-ssa-loop-ivopts.c b/gcc-4.2.1-5666.3/gcc/tree-ssa-loop-ivopts.c deleted file mode 100644 index 1d250d140..000000000 --- a/gcc-4.2.1-5666.3/gcc/tree-ssa-loop-ivopts.c +++ /dev/null @@ -1,5913 +0,0 @@ -/* Induction variable optimizations. - Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. - -This file is part of GCC. - -GCC is free software; you can redistribute it and/or modify it -under the terms of the GNU General Public License as published by the -Free Software Foundation; either version 2, or (at your option) any -later version. - -GCC is distributed in the hope that it will be useful, but WITHOUT -ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or -FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -for more details. - -You should have received a copy of the GNU General Public License -along with GCC; see the file COPYING. If not, write to the Free -Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA -02110-1301, USA. */ - -/* 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 "hashtab.h" -#include "tree-chrec.h" -#include "tree-scalar-evolution.h" -#include "cfgloop.h" -#include "params.h" -#include "langhooks.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. */ -}; - -/* The candidate - cost pair. */ -struct cost_pair -{ - struct iv_cand *cand; /* The candidate. */ - unsigned 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. */ - tree 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. */ - tree 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; - - /* Number of registers used in it. */ - unsigned regs_used; - - /* Numbers of iterations for all exits of the current loop. */ - htab_t niters; - - /* 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 maximum invariant id. */ - unsigned max_inv_id; - - /* 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; - - /* Whether to consider just related and important candidates when replacing a - use. */ - bool consider_all_candidates; -}; - -/* 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. */ - unsigned 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. */ - unsigned 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 = loop->single_exit; - - 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_generic_expr (file, use->stmt, TDF_SLIM); - 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)); -} - -/* Checks whether there exists number X such that X * B = A, counting modulo - 2^BITS. */ - -static bool -divide (unsigned bits, unsigned HOST_WIDE_INT a, unsigned HOST_WIDE_INT b, - HOST_WIDE_INT *x) -{ - unsigned HOST_WIDE_INT mask = ~(~(unsigned HOST_WIDE_INT) 0 << (bits - 1) << 1); - unsigned HOST_WIDE_INT inv, ex, val; - unsigned i; - - a &= mask; - b &= mask; - - /* First divide the whole equation by 2 as long as possible. */ - while (!(a & 1) && !(b & 1)) - { - a >>= 1; - b >>= 1; - bits--; - mask >>= 1; - } - - if (!(b & 1)) - { - /* If b is still even, a is odd and there is no such x. */ - return false; - } - - /* Find the inverse of b. We compute it as - b^(2^(bits - 1) - 1) (mod 2^bits). */ - inv = 1; - ex = b; - for (i = 0; i < bits - 1; i++) - { - inv = (inv * ex) & mask; - ex = (ex * ex) & mask; - } - - val = (a * inv) & mask; - - gcc_assert (((val * b) & mask) == a); - - if ((val >> (bits - 1)) & 1) - val |= ~mask; - - *x = val; - - return true; -} - -/* 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, tree stmt) -{ - basic_block bb = ip_normal_pos (loop), sbb = bb_for_stmt (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, tree stmt) -{ - basic_block cand_bb = bb_for_stmt (cand->incremented_at); - basic_block stmt_bb = bb_for_stmt (stmt); - block_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 = bsi_last (stmt_bb); ; bsi_prev (&bsi)) - { - if (bsi_stmt (bsi) == cand->incremented_at) - return false; - if (bsi_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, tree 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) - { - 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 class; - - if (!expr) - return false; - - code = TREE_CODE (expr); - class = 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 (class) - { - 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; -} - -/* Element of the table in that we cache the numbers of iterations obtained - from exits of the loop. */ - -struct nfe_cache_elt -{ - /* The edge for that the number of iterations is cached. */ - edge exit; - - /* Number of iterations corresponding to this exit, or NULL if it cannot be - determined. */ - tree niter; -}; - -/* Hash function for nfe_cache_elt E. */ - -static hashval_t -nfe_hash (const void *e) -{ - const struct nfe_cache_elt *elt = e; - - return htab_hash_pointer (elt->exit); -} - -/* Equality function for nfe_cache_elt E1 and edge E2. */ - -static int -nfe_eq (const void *e1, const void *e2) -{ - const struct nfe_cache_elt *elt1 = e1; - - return elt1->exit == e2; -} - -/* 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 nfe_cache_elt *nfe_desc; - struct tree_niter_desc desc; - PTR *slot; - - slot = htab_find_slot_with_hash (data->niters, exit, - htab_hash_pointer (exit), - INSERT); - - if (!*slot) - { - nfe_desc = xmalloc (sizeof (struct nfe_cache_elt)); - nfe_desc->exit = exit; - - /* 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) - && zero_p (desc.may_be_zero) - && !contains_abnormal_ssa_name_p (desc.niter)) - nfe_desc->niter = desc.niter; - else - nfe_desc->niter = NULL_TREE; - } - else - nfe_desc = *slot; - - return nfe_desc->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 = htab_create (10, nfe_hash, nfe_eq, free); - 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, op0, op1; - - /* 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 (TREE_CODE (expr) == NOP_EXPR - || TREE_CODE (expr) == CONVERT_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 PLUS_EXPR: - case MINUS_EXPR: - op0 = determine_base_object (TREE_OPERAND (expr, 0)); - op1 = determine_base_object (TREE_OPERAND (expr, 1)); - - if (!op1) - return op0; - - if (!op0) - return (code == PLUS_EXPR - ? op1 - : fold_build1 (NEGATE_EXPR, ptr_type_node, op1)); - - return fold_build2 (code, ptr_type_node, op0, op1); - - 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); - - if (step && integer_zerop (step)) - 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; - - if (!name_info (data, var)->iv) - { - bb = bb_for_stmt (SSA_NAME_DEF_STMT (var)); - - if (!bb - || !flow_bb_inside_loop_p (data->current_loop, bb)) - set_iv (data, var, var, NULL_TREE); - } - - 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 (tree phi) -{ - struct loop *loop = bb_for_stmt (phi)->loop_father; - tree name = PHI_RESULT (phi); - affine_iv iv; - - if (!is_gimple_reg (name)) - return NULL_TREE; - - if (!simple_iv (loop, phi, name, &iv, true)) - return NULL_TREE; - - return (zero_p (iv.step) ? NULL_TREE : iv.step); -} - -/* Finds basic ivs. */ - -static bool -find_bivs (struct ivopts_data *data) -{ - tree phi, step, type, base; - bool found = false; - struct loop *loop = data->current_loop; - - for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) - { - 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) - 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) -{ - tree phi, var; - struct iv *iv, *incr_iv; - struct loop *loop = data->current_loop; - basic_block incr_bb; - - for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) - { - 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 = bb_for_stmt (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, tree stmt, affine_iv *iv) -{ - tree lhs; - struct loop *loop = data->current_loop; - - iv->base = NULL_TREE; - iv->step = NULL_TREE; - - if (TREE_CODE (stmt) != MODIFY_EXPR) - return false; - - lhs = TREE_OPERAND (stmt, 0); - if (TREE_CODE (lhs) != SSA_NAME) - return false; - - if (!simple_iv (loop, stmt, TREE_OPERAND (stmt, 1), 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, tree stmt) -{ - affine_iv iv; - - if (!find_givs_in_stmt_scev (data, stmt, &iv)) - return; - - set_iv (data, TREE_OPERAND (stmt, 0), iv.base, iv.step); -} - -/* Finds general ivs in basic block BB. */ - -static void -find_givs_in_bb (struct ivopts_data *data, basic_block bb) -{ - block_stmt_iterator bsi; - - for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) - find_givs_in_stmt (data, bsi_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, - tree 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 = bb_for_stmt (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; - tree 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 (zero_p (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 (TREE_CODE (stmt) == PHI_NODE - || TREE_CODE (stmt) == MODIFY_EXPR); - - use = record_use (data, NULL, civ, stmt, USE_NONLINEAR_EXPR); - iv->use_id = use->id; - - return use; -} - -/* Checks whether the condition *COND_P in STMT is interesting - and if so, records it. */ - -static void -find_interesting_uses_cond (struct ivopts_data *data, tree stmt, tree *cond_p) -{ - tree *op0_p; - tree *op1_p; - struct iv *iv0 = NULL, *iv1 = NULL, *civ; - struct iv const_iv; - tree zero = integer_zero_node; - - const_iv.step = NULL_TREE; - - if (TREE_CODE (*cond_p) != SSA_NAME - && !COMPARISON_CLASS_P (*cond_p)) - return; - - if (TREE_CODE (*cond_p) == SSA_NAME) - { - op0_p = cond_p; - op1_p = &zero; - } - else - { - op0_p = &TREE_OPERAND (*cond_p, 0); - op1_p = &TREE_OPERAND (*cond_p, 1); - } - - if (TREE_CODE (*op0_p) == SSA_NAME) - iv0 = get_iv (data, *op0_p); - else - iv0 = &const_iv; - - if (TREE_CODE (*op1_p) == SSA_NAME) - iv1 = get_iv (data, *op1_p); - else - iv1 = &const_iv; - - if (/* When comparing with non-invariant value, we may not do any senseful - induction variable elimination. */ - (!iv0 || !iv1) - /* Eliminating condition based on two ivs would be nontrivial. - ??? TODO -- it is not really important to handle this case. */ - || (!zero_p (iv0->step) && !zero_p (iv1->step))) - { - find_interesting_uses_op (data, *op0_p); - find_interesting_uses_op (data, *op1_p); - return; - } - - if (zero_p (iv0->step) && zero_p (iv1->step)) - { - /* If both are invariants, this is a work for unswitching. */ - return; - } - - civ = XNEW (struct iv); - *civ = zero_p (iv0->step) ? *iv1: *iv0; - record_use (data, cond_p, 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. */ - -bool -expr_invariant_in_loop_p (struct loop *loop, tree expr) -{ - basic_block def_bb; - unsigned i, len; - - if (is_gimple_min_invariant (expr)) - return true; - - if (TREE_CODE (expr) == SSA_NAME) - { - def_bb = bb_for_stmt (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_CODE_LENGTH (TREE_CODE (expr)); - for (i = 0; i < len; i++) - if (!expr_invariant_in_loop_p (loop, TREE_OPERAND (expr, i))) - 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; - tree stmt; - tree *step_p; -}; - -static bool -idx_find_step (tree base, tree *idx, void *data) -{ - struct ifs_ivopts_data *dta = 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) - { - 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 (!iv->step) - return true; - - if (TREE_CODE (base) == ARRAY_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); - - if (!*dta->step_p) - *dta->step_p = step; - else - *dta->step_p = fold_build2 (PLUS_EXPR, sizetype, *dta->step_p, 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 *data) -{ - find_interesting_uses_op (data, *idx); - if (TREE_CODE (base) == ARRAY_REF) - { - find_interesting_uses_op (data, array_ref_element_size (base)); - find_interesting_uses_op (data, array_ref_low_bound (base)); - } - return true; -} - -/* Returns true if memory reference REF may be unaligned. */ - -static bool -may_be_unaligned_p (tree ref) -{ - 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 - && (base_align < GET_MODE_ALIGNMENT (mode) - || bitpos % GET_MODE_ALIGNMENT (mode) != 0 - || bitpos % BITS_PER_UNIT != 0)) - 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 COMPONENT_REF: - return DECL_NONADDRESSABLE_P (TREE_OPERAND (expr, 1)) - || may_be_nonaddressable_p (TREE_OPERAND (expr, 0)); - - case ARRAY_REF: - case ARRAY_RANGE_REF: - return 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. */ - /* APPLE LOCAL begin 6187262 */ - return ((AGGREGATE_TYPE_P (TREE_TYPE (expr)) - || TREE_CODE (TREE_TYPE (expr)) == VECTOR_TYPE) - && !(AGGREGATE_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))) - || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE)); - /* APPLE LOCAL end 6187262 */ - - default: - break; - } - - return false; -} - -/* Finds addresses in *OP_P inside STMT. */ - -static void -find_interesting_uses_address (struct ivopts_data *data, tree stmt, tree *op_p) -{ - tree base = *op_p, step = NULL; - 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 (stmt_ann (stmt)->has_volatile_ops) - goto fail; - - /* Ignore bitfields for now. Not really something terribly complicated - to handle. TODO. */ - if (TREE_CODE (base) == BIT_FIELD_REF) - goto fail; - - if (may_be_nonaddressable_p (base)) - goto fail; - - if (STRICT_ALIGNMENT - && may_be_unaligned_p (base)) - 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); - - if (step) - step = fold_build2 (PLUS_EXPR, type, step, astep); - else - step = astep; - } - } - - if (zero_p (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_p = &step; - if (!for_each_index (&base, idx_find_step, &ifs_ivopts_data) - || zero_p (step)) - goto fail; - - gcc_assert (TREE_CODE (base) != ALIGN_INDIRECT_REF); - gcc_assert (TREE_CODE (base) != MISALIGNED_INDIRECT_REF); - - 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, tree 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, tree stmt) -{ - struct iv *iv; - tree op, lhs, rhs; - ssa_op_iter iter; - use_operand_p use_p; - - find_invariants_stmt (data, stmt); - - if (TREE_CODE (stmt) == COND_EXPR) - { - find_interesting_uses_cond (data, stmt, &COND_EXPR_COND (stmt)); - return; - } - - if (TREE_CODE (stmt) == MODIFY_EXPR) - { - lhs = TREE_OPERAND (stmt, 0); - rhs = TREE_OPERAND (stmt, 1); - - 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 && !zero_p (iv->step)) - return; - } - - switch (TREE_CODE_CLASS (TREE_CODE (rhs))) - { - case tcc_comparison: - find_interesting_uses_cond (data, stmt, &TREE_OPERAND (stmt, 1)); - return; - - case tcc_reference: - find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 1)); - if (REFERENCE_CLASS_P (lhs)) - find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0)); - return; - - default: ; - } - - if (REFERENCE_CLASS_P (lhs) - && is_gimple_val (rhs)) - { - find_interesting_uses_address (data, stmt, &TREE_OPERAND (stmt, 0)); - find_interesting_uses_op (data, rhs); - return; - } - - /* TODO -- we should also handle address uses of type - - memory = call (whatever); - - and - - call (memory). */ - } - - if (TREE_CODE (stmt) == PHI_NODE - && bb_for_stmt (stmt) == data->current_loop->header) - { - lhs = PHI_RESULT (stmt); - iv = get_iv (data, lhs); - - if (iv && !zero_p (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) -{ - tree phi, def; - - for (phi = phi_nodes (exit->dest); phi; phi = PHI_CHAIN (phi)) - { - def = PHI_ARG_DEF_FROM_EDGE (phi, exit); - 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; - block_stmt_iterator bsi; - tree phi; - 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 (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) - find_interesting_uses_stmt (data, phi); - for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) - find_interesting_uses_stmt (data, bsi_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) - || zero_p (expr)) - return orig_expr; - - *offset = int_cst_value (expr); - return build_int_cst (orig_type, 0); - - 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 == PLUS_EXPR ? off0 + off1 : off0 - off1); - if (op0 == TREE_OPERAND (expr, 0) - && op1 == TREE_OPERAND (expr, 1)) - return orig_expr; - - if (zero_p (op1)) - expr = op0; - else if (zero_p (op0)) - { - if (code == PLUS_EXPR) - expr = op1; - else - expr = fold_build1 (NEGATE_EXPR, type, op1); - } - else - expr = fold_build2 (code, type, op0, op1); - - return fold_convert (orig_type, expr); - - case ARRAY_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 - && zero_p (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 = 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, tree 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); - if (step) - 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)) - continue; - - if (zero_p (cand->iv->step)) - { - if (zero_p (step)) - break; - } - else - { - if (step && 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_TREE); - 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_TREE); -} - -/* 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) -{ - tree phi, def; - struct iv_cand *cand; - - add_candidate (data, iv->base, iv->step, true, NULL); - - /* The same, but with initial value zero. */ - add_candidate (data, - build_int_cst (TREE_TYPE (iv->base), 0), - iv->step, true, NULL); - - phi = SSA_NAME_DEF_STMT (iv->ssa_name); - if (TREE_CODE (phi) == PHI_NODE) - { - /* 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 && !zero_p (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; - - 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. */ - add_candidate (data, build_int_cst (TREE_TYPE (iv->base), 0), - iv->step, true, use); - - /* Third, try removing the constant offset. */ - base = strip_offset (iv->base, &offset); - if (offset) - 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); - } -} - -/* 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, unsigned cost, - bitmap depends_on, tree value) -{ - unsigned i, s; - - if (cost == INFTY) - { - 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) -{ - unsigned cost = 0; - rtx set; - - for (; seq; seq = NEXT_INSN (seq)) - { - set = single_set (seq); - if (set) - cost += rtx_cost (set, SET); - 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); - } - else - x = gen_raw_REG (Pmode, (*regno)++); - - return gen_rtx_MEM (DECL_MODE (obj), 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 = 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) -{ - 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; - - 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 (); - - cost = seq_cost (seq); - if (MEM_P (rslt)) - cost += address_cost (XEXP (rslt, 0), TYPE_MODE (type)); - - 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, tree 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 (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 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 (bot), precision); - p1 = double_int_sext (tree_to_double_int (top), 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; - } -} - -/* Sets COMB to CST. */ - -static void -aff_combination_const (struct affine_tree_combination *comb, tree type, - unsigned HOST_WIDE_INT cst) -{ - unsigned prec = TYPE_PRECISION (type); - - comb->type = type; - comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1); - - comb->n = 0; - comb->rest = NULL_TREE; - comb->offset = cst & comb->mask; -} - -/* Sets COMB to single element ELT. */ - -static void -aff_combination_elt (struct affine_tree_combination *comb, tree type, tree elt) -{ - unsigned prec = TYPE_PRECISION (type); - - comb->type = type; - comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1); - - comb->n = 1; - comb->elts[0] = elt; - comb->coefs[0] = 1; - comb->rest = NULL_TREE; - comb->offset = 0; -} - -/* Scales COMB by SCALE. */ - -static void -aff_combination_scale (struct affine_tree_combination *comb, - unsigned HOST_WIDE_INT scale) -{ - unsigned i, j; - - if (scale == 1) - return; - - if (scale == 0) - { - aff_combination_const (comb, comb->type, 0); - return; - } - - comb->offset = (scale * comb->offset) & comb->mask; - for (i = 0, j = 0; i < comb->n; i++) - { - comb->coefs[j] = (scale * comb->coefs[i]) & comb->mask; - comb->elts[j] = comb->elts[i]; - if (comb->coefs[j] != 0) - j++; - } - comb->n = j; - - if (comb->rest) - { - if (comb->n < MAX_AFF_ELTS) - { - comb->coefs[comb->n] = scale; - comb->elts[comb->n] = comb->rest; - comb->rest = NULL_TREE; - comb->n++; - } - else - comb->rest = fold_build2 (MULT_EXPR, comb->type, comb->rest, - build_int_cst_type (comb->type, scale)); - } -} - -/* Adds ELT * SCALE to COMB. */ - -static void -aff_combination_add_elt (struct affine_tree_combination *comb, tree elt, - unsigned HOST_WIDE_INT scale) -{ - unsigned i; - - if (scale == 0) - return; - - for (i = 0; i < comb->n; i++) - if (operand_equal_p (comb->elts[i], elt, 0)) - { - comb->coefs[i] = (comb->coefs[i] + scale) & comb->mask; - if (comb->coefs[i]) - return; - - comb->n--; - comb->coefs[i] = comb->coefs[comb->n]; - comb->elts[i] = comb->elts[comb->n]; - - if (comb->rest) - { - gcc_assert (comb->n == MAX_AFF_ELTS - 1); - comb->coefs[comb->n] = 1; - comb->elts[comb->n] = comb->rest; - comb->rest = NULL_TREE; - comb->n++; - } - return; - } - if (comb->n < MAX_AFF_ELTS) - { - comb->coefs[comb->n] = scale; - comb->elts[comb->n] = elt; - comb->n++; - return; - } - - if (scale == 1) - elt = fold_convert (comb->type, elt); - else - elt = fold_build2 (MULT_EXPR, comb->type, - fold_convert (comb->type, elt), - build_int_cst_type (comb->type, scale)); - - if (comb->rest) - comb->rest = fold_build2 (PLUS_EXPR, comb->type, comb->rest, elt); - else - comb->rest = elt; -} - -/* Adds COMB2 to COMB1. */ - -static void -aff_combination_add (struct affine_tree_combination *comb1, - struct affine_tree_combination *comb2) -{ - unsigned i; - - comb1->offset = (comb1->offset + comb2->offset) & comb1->mask; - for (i = 0; i < comb2->n; i++) - aff_combination_add_elt (comb1, comb2->elts[i], comb2->coefs[i]); - if (comb2->rest) - aff_combination_add_elt (comb1, comb2->rest, 1); -} - -/* Convert COMB to TYPE. */ - -static void -aff_combination_convert (tree type, struct affine_tree_combination *comb) -{ - unsigned prec = TYPE_PRECISION (type); - unsigned i; - - /* If the precision of both types is the same, it suffices to change the type - of the whole combination -- the elements are allowed to have another type - equivalent wrto STRIP_NOPS. */ - if (prec == TYPE_PRECISION (comb->type)) - { - comb->type = type; - return; - } - - comb->mask = (((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1); - comb->offset = comb->offset & comb->mask; - - /* The type of the elements can be different from comb->type only as - much as what STRIP_NOPS would remove. We can just directly cast - to TYPE. */ - for (i = 0; i < comb->n; i++) - comb->elts[i] = fold_convert (type, comb->elts[i]); - if (comb->rest) - comb->rest = fold_convert (type, comb->rest); - - comb->type = type; -} - -/* Splits EXPR into an affine combination of parts. */ - -static void -tree_to_aff_combination (tree expr, tree type, - struct affine_tree_combination *comb) -{ - struct affine_tree_combination tmp; - enum tree_code code; - tree cst, core, toffset; - HOST_WIDE_INT bitpos, bitsize; - enum machine_mode mode; - int unsignedp, volatilep; - - STRIP_NOPS (expr); - - code = TREE_CODE (expr); - switch (code) - { - case INTEGER_CST: - aff_combination_const (comb, type, int_cst_value (expr)); - return; - - case PLUS_EXPR: - case MINUS_EXPR: - tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb); - tree_to_aff_combination (TREE_OPERAND (expr, 1), type, &tmp); - if (code == MINUS_EXPR) - aff_combination_scale (&tmp, -1); - aff_combination_add (comb, &tmp); - return; - - case MULT_EXPR: - cst = TREE_OPERAND (expr, 1); - if (TREE_CODE (cst) != INTEGER_CST) - break; - tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb); - aff_combination_scale (comb, int_cst_value (cst)); - return; - - case NEGATE_EXPR: - tree_to_aff_combination (TREE_OPERAND (expr, 0), type, comb); - aff_combination_scale (comb, -1); - return; - - case ADDR_EXPR: - core = get_inner_reference (TREE_OPERAND (expr, 0), &bitsize, &bitpos, - &toffset, &mode, &unsignedp, &volatilep, - false); - if (bitpos % BITS_PER_UNIT != 0) - break; - aff_combination_const (comb, type, bitpos / BITS_PER_UNIT); - core = build_fold_addr_expr (core); - if (TREE_CODE (core) == ADDR_EXPR) - aff_combination_add_elt (comb, core, 1); - else - { - tree_to_aff_combination (core, type, &tmp); - aff_combination_add (comb, &tmp); - } - if (toffset) - { - tree_to_aff_combination (toffset, type, &tmp); - aff_combination_add (comb, &tmp); - } - return; - - default: - break; - } - - aff_combination_elt (comb, type, expr); -} - -/* Creates EXPR + ELT * SCALE in TYPE. MASK is the mask for width of TYPE. */ - -static tree -add_elt_to_tree (tree expr, tree type, tree elt, unsigned HOST_WIDE_INT scale, - unsigned HOST_WIDE_INT mask) -{ - enum tree_code code; - - scale &= mask; - elt = fold_convert (type, elt); - - if (scale == 1) - { - if (!expr) - return elt; - - return fold_build2 (PLUS_EXPR, type, expr, elt); - } - - if (scale == mask) - { - if (!expr) - return fold_build1 (NEGATE_EXPR, type, elt); - - return fold_build2 (MINUS_EXPR, type, expr, elt); - } - - if (!expr) - return fold_build2 (MULT_EXPR, type, elt, - build_int_cst_type (type, scale)); - - if ((scale | (mask >> 1)) == mask) - { - /* Scale is negative. */ - code = MINUS_EXPR; - scale = (-scale) & mask; - } - else - code = PLUS_EXPR; - - elt = fold_build2 (MULT_EXPR, type, elt, - build_int_cst_type (type, scale)); - return fold_build2 (code, type, expr, elt); -} - -/* Copies the tree elements of COMB to ensure that they are not shared. */ - -static void -unshare_aff_combination (struct affine_tree_combination *comb) -{ - unsigned i; - - for (i = 0; i < comb->n; i++) - comb->elts[i] = unshare_expr (comb->elts[i]); - if (comb->rest) - comb->rest = unshare_expr (comb->rest); -} - -/* Makes tree from the affine combination COMB. */ - -static tree -aff_combination_to_tree (struct affine_tree_combination *comb) -{ - tree type = comb->type; - tree expr = comb->rest; - unsigned i; - unsigned HOST_WIDE_INT off, sgn; - - if (comb->n == 0 && comb->offset == 0) - { - if (expr) - { - /* Handle the special case produced by get_computation_aff when - the type does not fit in HOST_WIDE_INT. */ - return fold_convert (type, expr); - } - else - return build_int_cst (type, 0); - } - - gcc_assert (comb->n == MAX_AFF_ELTS || comb->rest == NULL_TREE); - - for (i = 0; i < comb->n; i++) - expr = add_elt_to_tree (expr, type, comb->elts[i], comb->coefs[i], - comb->mask); - - /* APPLE LOCAL begin 6755006 */ - if (( ! TYPE_UNSIGNED (comb->type)) - && ((comb->offset | (comb->mask >> 1)) == comb->mask)) - /* APPLE LOCAL end 6755006 */ - { - /* Offset is negative. */ - off = (-comb->offset) & comb->mask; - sgn = comb->mask; - } - else - { - off = comb->offset; - sgn = 1; - } - return add_elt_to_tree (expr, type, build_int_cst_type (type, off), sgn, - comb->mask); -} - -/* Folds EXPR using the affine expressions framework. */ - -static tree -fold_affine_expr (tree expr) -{ - tree type = TREE_TYPE (expr); - struct affine_tree_combination comb; - - if (TYPE_PRECISION (type) > HOST_BITS_PER_WIDE_INT) - return expr; - - tree_to_aff_combination (expr, type, &comb); - return aff_combination_to_tree (&comb); -} - -/* 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 ((TREE_CODE (*a) == NOP_EXPR - || TREE_CODE (*a) == CONVERT_EXPR)) - { - suba = TREE_OPERAND (*a, 0); - wider_type = TREE_TYPE (suba); - if (TYPE_PRECISION (wider_type) < TYPE_PRECISION (atype)) - return atype; - } - else - return atype; - - if ((TREE_CODE (*b) == NOP_EXPR - || TREE_CODE (*b) == CONVERT_EXPR)) - { - 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, tree 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; - tree utype = TREE_TYPE (ubase), ctype = TREE_TYPE (cbase); - tree common_type; - tree uutype; - tree expr, delta; - tree ratio; - unsigned HOST_WIDE_INT ustepi, cstepi; - HOST_WIDE_INT ratioi; - struct affine_tree_combination cbase_aff, expr_aff; - tree cstep_orig = cstep, ustep_orig = ustep; - double_int rat; - - if (TYPE_PRECISION (utype) > TYPE_PRECISION (ctype)) - { - /* We do not have a precision to express the values of use. */ - return false; - } - - expr = var_at_stmt (loop, cand, at); - - if (TREE_TYPE (expr) != ctype) - { - /* This may happen with the original ivs. */ - expr = fold_convert (ctype, expr); - } - - if (TYPE_UNSIGNED (utype)) - uutype = utype; - else - { - uutype = unsigned_type_for (utype); - ubase = fold_convert (uutype, ubase); - ustep = fold_convert (uutype, ustep); - } - - if (uutype != ctype) - { - expr = fold_convert (uutype, expr); - cbase = fold_convert (uutype, cbase); - cstep = fold_convert (uutype, cstep); - - /* If the conversion is not noop, we must take it into account when - considering the value of the step. */ - if (TYPE_PRECISION (utype) < TYPE_PRECISION (ctype)) - cstep_orig = cstep; - } - - if (cst_and_fits_in_hwi (cstep_orig) - && cst_and_fits_in_hwi (ustep_orig)) - { - ustepi = int_cst_value (ustep_orig); - cstepi = int_cst_value (cstep_orig); - - if (!divide (TYPE_PRECISION (uutype), ustepi, cstepi, &ratioi)) - { - /* TODO maybe consider case when ustep divides cstep and the ratio is - a power of 2 (so that the division is fast to execute)? We would - need to be much more careful with overflows etc. then. */ - return false; - } - - ratio = build_int_cst_type (uutype, ratioi); - } - else - { - if (!constant_multiple_of (ustep_orig, cstep_orig, &rat)) - return false; - ratio = double_int_to_tree (uutype, rat); - - /* Ratioi is only used to detect special cases when the multiplicative - factor is 1 or -1, so if rat does not fit to HOST_WIDE_INT, we may - set it to 0. */ - if (double_int_fits_in_shwi_p (rat)) - ratioi = double_int_to_shwi (rat); - else - ratioi = 0; - } - - /* 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); - - /* We may need to shift the value if we are after the increment. */ - if (stmt_after_increment (loop, cand, at)) - { - if (uutype != common_type) - cstep = fold_convert (common_type, cstep); - cbase = fold_build2 (PLUS_EXPR, common_type, cbase, cstep); - } - - /* use = ubase - ratio * cbase + ratio * var. - - In general case ubase + ratio * (var - cbase) could be better (one less - multiplication), but often it is possible to eliminate redundant parts - of computations from (ubase - ratio * cbase) term, and if it does not - happen, fold is able to apply the distributive law to obtain this form - anyway. */ - - if (TYPE_PRECISION (common_type) > HOST_BITS_PER_WIDE_INT) - { - /* Let's compute in trees and just return the result in AFF. This case - should not be very common, and fold itself is not that bad either, - so making the aff. functions more complicated to handle this case - is not that urgent. */ - if (ratioi == 1) - { - delta = fold_build2 (MINUS_EXPR, common_type, ubase, cbase); - if (uutype != common_type) - delta = fold_convert (uutype, delta); - expr = fold_build2 (PLUS_EXPR, uutype, expr, delta); - } - else if (ratioi == -1) - { - delta = fold_build2 (PLUS_EXPR, common_type, ubase, cbase); - if (uutype != common_type) - delta = fold_convert (uutype, delta); - expr = fold_build2 (MINUS_EXPR, uutype, delta, expr); - } - else - { - delta = fold_build2 (MULT_EXPR, common_type, cbase, ratio); - delta = fold_build2 (MINUS_EXPR, common_type, ubase, delta); - if (uutype != common_type) - delta = fold_convert (uutype, delta); - expr = fold_build2 (MULT_EXPR, uutype, ratio, expr); - expr = fold_build2 (PLUS_EXPR, uutype, delta, expr); - } - - aff->type = uutype; - aff->n = 0; - aff->offset = 0; - aff->mask = 0; - aff->rest = expr; - return true; - } - - /* If we got here, the types fits in HOST_WIDE_INT, thus it must be - possible to compute ratioi. */ - gcc_assert (ratioi); - - tree_to_aff_combination (ubase, common_type, aff); - tree_to_aff_combination (cbase, common_type, &cbase_aff); - tree_to_aff_combination (expr, uutype, &expr_aff); - aff_combination_scale (&cbase_aff, -ratioi); - aff_combination_scale (&expr_aff, ratioi); - aff_combination_add (aff, &cbase_aff); - if (common_type != uutype) - aff_combination_convert (uutype, aff); - aff_combination_add (aff, &expr_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, tree at) -{ - struct affine_tree_combination 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) -{ - 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); - 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 = 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 = entry1; - const struct mbc_entry *e2 = 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) -{ - 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); - - 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 address. */ - -bool -multiplier_allowed_in_address_p (HOST_WIDE_INT ratio) -{ -#define MAX_RATIO 128 - static sbitmap valid_mult; - - if (!valid_mult) - { - rtx reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); - rtx addr; - HOST_WIDE_INT i; - - valid_mult = sbitmap_alloc (2 * MAX_RATIO + 1); - sbitmap_zero (valid_mult); - 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 (Pmode, addr)) - SET_BIT (valid_mult, 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, 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, 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. The created memory accesses MODE. - - TODO -- there must be some better way. This all is quite crude. */ - -static unsigned -get_address_cost (bool symbol_present, bool var_present, - unsigned HOST_WIDE_INT offset, HOST_WIDE_INT ratio) -{ - static bool initialized = false; - static HOST_WIDE_INT rat, off; - static HOST_WIDE_INT min_offset, max_offset; - static unsigned costs[2][2][2][2]; - unsigned cost, acost; - bool offset_p, ratio_p; - HOST_WIDE_INT s_offset; - unsigned HOST_WIDE_INT mask; - unsigned bits; - - if (!initialized) - { - HOST_WIDE_INT i; - int old_cse_not_expected; - unsigned sym_p, var_p, off_p, rat_p, add_c; - rtx seq, addr, base; - rtx reg0, reg1; - - initialized = true; - - reg1 = gen_raw_REG (Pmode, LAST_VIRTUAL_REGISTER + 1); - - addr = gen_rtx_fmt_ee (PLUS, Pmode, reg1, NULL_RTX); - for (i = 1; i <= 1 << 20; i <<= 1) - { - XEXP (addr, 1) = gen_int_mode (i, Pmode); - if (!memory_address_p (Pmode, addr)) - break; - } - max_offset = i >> 1; - off = max_offset; - - for (i = 1; i <= 1 << 20; i <<= 1) - { - XEXP (addr, 1) = gen_int_mode (-i, Pmode); - if (!memory_address_p (Pmode, addr)) - break; - } - min_offset = -(i >> 1); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "get_address_cost:\n"); - fprintf (dump_file, " min offset %d\n", (int) min_offset); - fprintf (dump_file, " max offset %d\n", (int) max_offset); - } - - rat = 1; - for (i = 2; i <= MAX_RATIO; i++) - if (multiplier_allowed_in_address_p (i)) - { - rat = 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, Pmode)); - - if (var_p) - addr = gen_rtx_fmt_ee (PLUS, Pmode, addr, reg1); - - if (sym_p) - { - base = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup ("")); - if (off_p) - base = gen_rtx_fmt_e (CONST, Pmode, - gen_rtx_fmt_ee (PLUS, Pmode, - base, - gen_int_mode (off, Pmode))); - } - else if (off_p) - base = gen_int_mode (off, 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 (Pmode, addr); - cse_not_expected = old_cse_not_expected; - seq = get_insns (); - end_sequence (); - - acost = seq_cost (seq); - acost += address_cost (addr, Pmode); - - if (!acost) - acost = 1; - costs[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); - for (i = 0; i < 8; i++) - { - var_p = i & 1; - off_p = (i >> 1) & 1; - rat_p = (i >> 2) & 1; - - acost = costs[0][1][off_p][rat_p] + 1; - if (var_p) - acost += add_c; - - if (acost < costs[1][var_p][off_p][rat_p]) - costs[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[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 <= s_offset && s_offset <= max_offset); - ratio_p = (ratio != 1 - && multiplier_allowed_in_address_p (ratio)); - - if (ratio != 1 && !ratio_p) - cost += multiply_by_cost (ratio, Pmode); - - if (s_offset && !offset_p && !symbol_present) - { - cost += add_cost (Pmode); - var_present = true; - } - - acost = costs[symbol_present][var_present][offset_p][ratio_p]; - return cost + acost; -} - -/* Estimates cost of forcing expression EXPR into a variable. */ - -unsigned -force_expr_to_var_cost (tree expr) -{ - static bool costs_initialized = false; - static unsigned integer_cost; - static unsigned symbol_cost; - static unsigned address_cost; - tree op0, op1; - unsigned cost0, cost1, cost; - enum machine_mode mode; - - if (!costs_initialized) - { - tree var = create_tmp_var_raw (integer_type_node, "test_var"); - rtx x = gen_rtx_MEM (DECL_MODE (var), - gen_rtx_SYMBOL_REF (Pmode, "test_var")); - tree addr; - tree type = build_pointer_type (integer_type_node); - - integer_cost = computation_cost (build_int_cst (integer_type_node, - 2000)); - - SET_DECL_RTL (var, x); - TREE_STATIC (var) = 1; - addr = build1 (ADDR_EXPR, type, var); - symbol_cost = computation_cost (addr) + 1; - - address_cost - = computation_cost (build2 (PLUS_EXPR, type, - addr, - build_int_cst (type, 2000))) + 1; - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "force_expr_to_var_cost:\n"); - fprintf (dump_file, " integer %d\n", (int) integer_cost); - fprintf (dump_file, " symbol %d\n", (int) symbol_cost); - fprintf (dump_file, " address %d\n", (int) address_cost); - fprintf (dump_file, " other %d\n", (int) target_spill_cost); - fprintf (dump_file, "\n"); - } - - costs_initialized = true; - } - - STRIP_NOPS (expr); - - if (SSA_VAR_P (expr)) - return 0; - - if (TREE_INVARIANT (expr)) - { - if (TREE_CODE (expr) == INTEGER_CST) - return integer_cost; - - 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 symbol_cost; - } - - return address_cost; - } - - switch (TREE_CODE (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 = 0; - else - cost0 = force_expr_to_var_cost (op0); - - if (is_gimple_val (op1)) - cost1 = 0; - else - cost1 = force_expr_to_var_cost (op1); - - break; - - default: - /* Just an arbitrary value, FIXME. */ - return target_spill_cost; - } - - mode = TYPE_MODE (TREE_TYPE (expr)); - switch (TREE_CODE (expr)) - { - case PLUS_EXPR: - case MINUS_EXPR: - cost = add_cost (mode); - break; - - case MULT_EXPR: - if (cst_and_fits_in_hwi (op0)) - cost = multiply_by_cost (int_cst_value (op0), mode); - else if (cst_and_fits_in_hwi (op1)) - cost = multiply_by_cost (int_cst_value (op1), mode); - else - return target_spill_cost; - break; - - default: - gcc_unreachable (); - } - - cost += cost0; - 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. */ - return cost < target_spill_cost ? cost : target_spill_cost; -} - -/* Estimates cost of forcing EXPR into a variable. DEPENDS_ON is a set of the - invariants the computation depends on. */ - -static unsigned -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); -} - -/* 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 unsigned -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 target_spill_cost; - } - - *offset += bitpos / BITS_PER_UNIT; - if (TREE_STATIC (core) - || DECL_EXTERNAL (core)) - { - *symbol_present = true; - *var_present = false; - return 0; - } - - *symbol_present = false; - *var_present = true; - return 0; -} - -/* 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 unsigned -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; - unsigned cost; - - gcc_assert (TREE_CODE (e1) == ADDR_EXPR); - - if (ptr_difference_const (e1, e2, &diff)) - { - *offset += diff; - *symbol_present = false; - *var_present = false; - return 0; - } - - if (e2 == integer_zero_node) - 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 += force_var_cost (data, e2, depends_on); - cost += add_cost (Pmode); - - 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 unsigned -difference_cost (struct ivopts_data *data, - tree e1, tree e2, bool *symbol_present, bool *var_present, - unsigned HOST_WIDE_INT *offset, bitmap *depends_on) -{ - unsigned 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 0; - } - *var_present = true; - if (zero_p (e2)) - return force_var_cost (data, e1, depends_on); - - if (zero_p (e1)) - { - cost = force_var_cost (data, e2, depends_on); - cost += multiply_by_cost (-1, mode); - - return cost; - } - - cost = force_var_cost (data, e1, depends_on); - cost += force_var_cost (data, e2, depends_on); - cost += add_cost (mode); - - 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 unsigned -get_computation_cost_at (struct ivopts_data *data, - struct iv_use *use, struct iv_cand *cand, - bool address_p, bitmap *depends_on, tree at) -{ - tree ubase = use->iv->base, ustep = use->iv->step; - tree cbase, cstep; - tree utype = TREE_TYPE (ubase), ctype; - unsigned HOST_WIDE_INT ustepi, cstepi, offset = 0; - HOST_WIDE_INT ratio, aratio; - bool var_present, symbol_present; - unsigned cost = 0, n_sums; - - *depends_on = NULL; - - /* Only consider real candidates. */ - if (!cand->iv) - return INFTY; - - 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 INFTY; - } - - 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 INFTY; - } - - 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 (cst_and_fits_in_hwi (ustep) - && cst_and_fits_in_hwi (cstep)) - { - ustepi = int_cst_value (ustep); - - if (!divide (TYPE_PRECISION (utype), ustepi, cstepi, &ratio)) - return INFTY; - } - else - { - double_int rat; - - if (!constant_multiple_of (ustep, cstep, &rat)) - return INFTY; - - if (double_int_fits_in_shwi_p (rat)) - ratio = double_int_to_shwi (rat); - else - return INFTY; - } - - /* 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, integer_zero_node, - &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 += add_cost (TYPE_MODE (ctype)); - cost += difference_cost (data, - ubase, integer_zero_node, - &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 cost + get_address_cost (symbol_present, var_present, offset, ratio); - - /* Otherwise estimate the costs for computing the expression. */ - aratio = ratio > 0 ? ratio : -ratio; - if (!symbol_present && !var_present && !offset) - { - if (ratio != 1) - cost += multiply_by_cost (ratio, TYPE_MODE (ctype)); - - return cost; - } - - if (aratio != 1) - cost += multiply_by_cost (aratio, TYPE_MODE (ctype)); - - n_sums = 1; - if (var_present - /* Symbol + offset should be compile-time computable. */ - && (symbol_present || offset)) - n_sums++; - - return cost + n_sums * add_cost (TYPE_MODE (ctype)); - -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 INFTY; - - if (address_p) - comp = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (comp)), comp); - - return computation_cost (comp); - } -} - -/* 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 unsigned -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; - unsigned 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, 0, 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 cost != INFTY; -} - -/* 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; - unsigned cost = get_computation_cost (data, use, cand, true, &depends_on); - - set_use_iv_cost (data, use, cand, cost, depends_on, NULL_TREE); - - return cost != INFTY; -} - -/* Computes value of induction variable IV in iteration NITER. */ - -static tree -iv_value (struct iv *iv, tree niter) -{ - tree val; - tree type = TREE_TYPE (iv->base); - - niter = fold_convert (type, niter); - val = fold_build2 (MULT_EXPR, type, iv->step, niter); - - return fold_build2 (PLUS_EXPR, type, iv->base, val); -} - -/* Computes value of candidate CAND at position AT in iteration NITER. */ - -static tree -cand_value_at (struct loop *loop, struct iv_cand *cand, tree at, tree niter) -{ - tree val = iv_value (cand->iv, niter); - tree type = TREE_TYPE (cand->iv->base); - - if (stmt_after_increment (loop, cand, at)) - val = fold_build2 (PLUS_EXPR, type, val, cand->iv->step); - - return val; -} - -/* 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 = bb_for_stmt (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, nit_type; - tree wider_type, period, per_type; - struct loop *loop = data->current_loop; - - if (TREE_CODE (cand->iv->step) != INTEGER_CST) - return false; - - /* For now works only for exits that dominate the loop latch. TODO -- extend - for other conditions inside loop body. */ - ex_bb = bb_for_stmt (use->stmt); - if (use->stmt != last_stmt (ex_bb) - || TREE_CODE (use->stmt) != COND_EXPR) - return false; - if (!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; - - nit_type = TREE_TYPE (nit); - - /* Determine whether we may use the variable to test whether niter iterations - elapsed. This is the case iff the period of the induction variable is - greater than the number of iterations. */ - period = iv_period (cand->iv); - if (!period) - return false; - per_type = TREE_TYPE (period); - - wider_type = TREE_TYPE (period); - if (TYPE_PRECISION (nit_type) < TYPE_PRECISION (per_type)) - wider_type = per_type; - else - wider_type = nit_type; - - if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, - fold_convert (wider_type, period), - fold_convert (wider_type, nit)))) - return false; - - *bound = fold_affine_expr (cand_value_at (loop, cand, use->stmt, nit)); - 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, op, cond; - bitmap depends_on = NULL; - unsigned cost; - - /* Only consider real candidates. */ - if (!cand->iv) - { - set_use_iv_cost (data, use, cand, INFTY, NULL, NULL_TREE); - return false; - } - - if (may_eliminate_iv (data, use, cand, &bound)) - { - cost = force_var_cost (data, bound, &depends_on); - - set_use_iv_cost (data, use, cand, cost, depends_on, bound); - return cost != INFTY; - } - - /* The induction variable elimination failed; just express the original - giv. If it is compared with an invariant, note that we cannot get - rid of it. */ - cost = get_computation_cost (data, use, cand, false, &depends_on); - - cond = *use->op_p; - if (TREE_CODE (cond) != SSA_NAME) - { - op = TREE_OPERAND (cond, 0); - if (TREE_CODE (op) == SSA_NAME && !zero_p (get_iv (data, op)->step)) - op = TREE_OPERAND (cond, 1); - if (TREE_CODE (op) == SSA_NAME) - { - op = get_iv (data, op)->base; - fd_ivopts_data = data; - walk_tree (&op, find_depends, &depends_on, NULL); - } - } - - set_use_iv_cost (data, use, cand, cost, depends_on, NULL); - return cost != INFTY; -} - -/* 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\tdepends on\n"); - for (j = 0; j < use->n_map_members; j++) - { - if (!use->cost_map[j].cand - || use->cost_map[j].cost == INFTY) - continue; - - fprintf (dump_file, " %d\t%d\t", - use->cost_map[j].cand->id, - use->cost_map[j].cost); - 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) -{ - unsigned cost_base, 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))); - - cand->cost = cost_step + cost_base / AVG_LOOP_NITER (current_loop); - - /* Prefer the original iv unless we may gain something by replacing it; - this is not really relevant for artificial ivs created by other - passes. */ - if (cand->pos == IP_ORIGINAL - && !DECL_ARTIFICIAL (SSA_NAME_VAR (cand->var_before))) - cand->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))) - cand->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) -{ - return global_cost_for_size (size, data->regs_used, n_iv_uses (data)); -} - -/* For each size of the induction variable set determine the penalty. */ - -static void -determine_set_costs (struct ivopts_data *data) -{ - unsigned j, n; - tree phi, 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_small_cost %d\n", target_small_cost); - fprintf (dump_file, " target_pres_cost %d\n", target_pres_cost); - fprintf (dump_file, " target_spill_cost %d\n", target_spill_cost); - } - - n = 0; - for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) - { - 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) -{ - if (!a) - return false; - - if (!b) - return true; - - if (a->cost < b->cost) - return true; - - if (a->cost > b->cost) - 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) -{ - unsigned cost = 0; - - cost += ivs->cand_use_cost; - cost += ivs->cand_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 -= 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 += 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 unsigned -iv_ca_cost (struct iv_ca *ivs) -{ - return (ivs->bad_uses ? INFTY : 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 = 0; - nw->cand_cost = 0; - nw->n_invariant_uses = XCNEWVEC (unsigned, data->max_inv_id + 1); - nw->cost = 0; - - 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; - - fprintf (file, " cost %d\n", iv_ca_cost (ivs)); - 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 unsigned -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, 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 unsigned -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; - unsigned 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 INFTY; - } - - *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 unsigned -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, 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 (acost < best_cost) - { - 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) -{ - unsigned 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. Only if it 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 (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 (act_cost < best_cost) - { - best_cost = act_cost; - - iv_ca_delta_free (&best_delta); - best_delta = act_delta; - } - else - iv_ca_delta_free (&act_delta); - } - - if (best_cost == INFTY) - { - 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) - 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 (act_cost < best_cost) - { - 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 (best_cost != INFTY); -} - -/* 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, acost, best_cost = iv_ca_cost (ivs), n_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 (acost < best_cost) - { - 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 (best_cost == iv_ca_cost (ivs)); - 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)) - fprintf (dump_file, "Final cost %d\n\n", iv_ca_cost (set)); - - 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) -{ - block_stmt_iterator incr_pos; - tree base; - bool after = false; - - if (!cand->iv) - return; - - switch (cand->pos) - { - case IP_NORMAL: - incr_pos = bsi_last (ip_normal_pos (data->current_loop)); - break; - - case IP_END: - incr_pos = bsi_last (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); - } -} - -/* 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 (tree stmt, bool including_defined_name) -{ - if (TREE_CODE (stmt) == PHI_NODE) - { - if (!including_defined_name) - { - /* Prevent the ssa name defined by the statement from being removed. */ - SET_PHI_RESULT (stmt, NULL); - } - remove_phi_node (stmt, NULL_TREE); - } - else - { - block_stmt_iterator bsi = bsi_for_stmt (stmt); - - bsi_remove (&bsi, true); - } -} - -/* 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, stmts, tgt, ass; - block_stmt_iterator bsi, pbsi; - - /* 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; - - gcc_assert (TREE_CODE (use->stmt) == MODIFY_EXPR); - gcc_assert (TREE_OPERAND (use->stmt, 0) == 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. */ - op = TREE_OPERAND (use->stmt, 1); - if (TREE_CODE (op) == PLUS_EXPR - || TREE_CODE (op) == MINUS_EXPR) - { - if (TREE_OPERAND (op, 0) == cand->var_before) - op = TREE_OPERAND (op, 1); - else if (TREE_CODE (op) == PLUS_EXPR - && TREE_OPERAND (op, 1) == cand->var_before) - op = TREE_OPERAND (op, 0); - 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); - - switch (TREE_CODE (use->stmt)) - { - case PHI_NODE: - tgt = PHI_RESULT (use->stmt); - - /* If we should keep the biv, do not replace it. */ - if (name_info (data, tgt)->preserve_biv) - return; - - pbsi = bsi = bsi_start (bb_for_stmt (use->stmt)); - while (!bsi_end_p (pbsi) - && TREE_CODE (bsi_stmt (pbsi)) == LABEL_EXPR) - { - bsi = pbsi; - bsi_next (&pbsi); - } - break; - - case MODIFY_EXPR: - tgt = TREE_OPERAND (use->stmt, 0); - bsi = bsi_for_stmt (use->stmt); - break; - - default: - gcc_unreachable (); - } - - op = force_gimple_operand (comp, &stmts, false, SSA_NAME_VAR (tgt)); - - if (TREE_CODE (use->stmt) == PHI_NODE) - { - if (stmts) - bsi_insert_after (&bsi, stmts, BSI_CONTINUE_LINKING); - ass = build2 (MODIFY_EXPR, TREE_TYPE (tgt), tgt, op); - bsi_insert_after (&bsi, ass, BSI_NEW_STMT); - remove_statement (use->stmt, false); - SSA_NAME_DEF_STMT (tgt) = ass; - } - else - { - if (stmts) - bsi_insert_before (&bsi, stmts, BSI_SAME_STMT); - TREE_OPERAND (use->stmt, 1) = op; - } -} - -/* 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) - { - 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 (aref && SSA_VAR_P (aref) && get_subvars_for_var (aref)) - return unshare_expr (sv); - - 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 = var_ann (var)->symbol_mem_tag; - gcc_assert (tag != NULL_TREE); - return tag; - } - else - { - if (!DECL_P (var)) - return NULL_TREE; - - tag = var_ann (var)->symbol_mem_tag; - 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) -{ - struct affine_tree_combination aff; - block_stmt_iterator bsi = bsi_for_stmt (use->stmt); - tree ref; - - get_computation_aff (data->current_loop, use, cand, use->stmt, &aff); - unshare_aff_combination (&aff); - - ref = create_mem_ref (&bsi, TREE_TYPE (*use->op_p), &aff); - 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; - tree *op_p, cond, op, stmts, bound; - block_stmt_iterator bsi = bsi_for_stmt (use->stmt); - enum tree_code compare; - struct cost_pair *cp = get_use_iv_cost (data, use, cand); - - bound = cp->value; - if (bound) - { - tree var = var_at_stmt (data->current_loop, cand, use->stmt); - tree var_type = TREE_TYPE (var); - - compare = iv_elimination_compare (data, use); - bound = fold_convert (var_type, bound); - op = force_gimple_operand (unshare_expr (bound), &stmts, - true, NULL_TREE); - - if (stmts) - bsi_insert_before (&bsi, stmts, BSI_SAME_STMT); - - *use->op_p = build2 (compare, boolean_type_node, var, op); - update_stmt (use->stmt); - return; - } - - /* The induction variable elimination failed; just express the original - giv. */ - comp = get_computation (data->current_loop, use, cand); - - cond = *use->op_p; - op_p = &TREE_OPERAND (cond, 0); - if (TREE_CODE (*op_p) != SSA_NAME - || zero_p (get_iv (data, *op_p)->step)) - op_p = &TREE_OPERAND (cond, 1); - - op = force_gimple_operand (comp, &stmts, true, SSA_NAME_VAR (*op_p)); - if (stmts) - bsi_insert_before (&bsi, stmts, BSI_SAME_STMT); - - *op_p = op; -} - -/* Rewrites USE using candidate CAND. */ - -static void -rewrite_use (struct ivopts_data *data, - struct iv_use *use, struct iv_cand *cand) -{ - 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 (); - } - mark_new_vars_to_rename (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 - && !zero_p (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; - - htab_empty (data->niters); - - 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); - htab_delete (data->niters); - - 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; - - data->current_loop = 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_generic_expr (dump_file, last_stmt (exit->src), 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 (struct loops *loops) -{ - struct loop *loop; - struct ivopts_data data; - - tree_ssa_iv_optimize_init (&data); - - /* Optimize the loops starting with the innermost ones. */ - loop = loops->tree_root; - while (loop->inner) - loop = loop->inner; - - /* Scan the loops, inner ones first. */ - while (loop != loops->tree_root) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - flow_loop_dump (loop, dump_file, NULL, 1); - - tree_ssa_iv_optimize_loop (&data, loop); - - if (loop->next) - { - loop = loop->next; - while (loop->inner) - loop = loop->inner; - } - else - loop = loop->outer; - } - - tree_ssa_iv_optimize_finalize (&data); -} |