1 /* Data flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
40 #include "diagnostic.h"
41 #include "tree-dump.h"
42 #include "tree-gimple.h"
43 #include "tree-flow.h"
44 #include "tree-inline.h"
45 #include "tree-pass.h"
50 /* Build and maintain data flow information for trees. */
52 /* Counters used to display DFA and SSA statistics. */
68 /* State information for find_vars_r. */
71 /* Hash table used to avoid adding the same variable more than once. */
76 /* Local functions. */
77 static void collect_dfa_stats (struct dfa_stats_d *);
78 static tree collect_dfa_stats_r (tree *, int *, void *);
79 static void add_immediate_use (tree, tree);
80 static tree find_vars_r (tree *, int *, void *);
81 static void add_referenced_var (tree, struct walk_state *);
82 static void compute_immediate_uses_for_phi (tree, bool (*)(tree));
83 static void compute_immediate_uses_for_stmt (tree, int, bool (*)(tree));
86 /* Global declarations. */
88 /* Array of all variables referenced in the function. */
89 varray_type referenced_vars;
92 /*---------------------------------------------------------------------------
93 Dataflow analysis (DFA) routines
94 ---------------------------------------------------------------------------*/
95 /* Find all the variables referenced in the function. This function
96 builds the global arrays REFERENCED_VARS and CALL_CLOBBERED_VARS.
98 Note that this function does not look for statement operands, it simply
99 determines what variables are referenced in the program and detects
100 various attributes for each variable used by alias analysis and the
104 find_referenced_vars (void)
108 block_stmt_iterator si;
109 struct walk_state walk_state;
111 cgraph_reset_static_var_maps ();
112 vars_found = htab_create (50, htab_hash_pointer, htab_eq_pointer, NULL);
113 memset (&walk_state, 0, sizeof (walk_state));
114 walk_state.vars_found = vars_found;
117 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
119 tree *stmt_p = bsi_stmt_ptr (si);
120 walk_tree (stmt_p, find_vars_r, &walk_state, NULL);
123 htab_delete (vars_found);
126 struct tree_opt_pass pass_referenced_vars =
130 find_referenced_vars, /* execute */
133 0, /* static_pass_number */
135 PROP_gimple_leh | PROP_cfg, /* properties_required */
136 PROP_referenced_vars, /* properties_provided */
137 0, /* properties_destroyed */
138 0, /* todo_flags_start */
139 0, /* todo_flags_finish */
144 /* Compute immediate uses.
146 CALC_FOR is an optional function pointer which indicates whether
147 immediate uses information should be calculated for a given SSA
148 variable. If NULL, then information is computed for all
151 FLAGS is one of {TDFA_USE_OPS, TDFA_USE_VOPS}. It is used by
152 compute_immediate_uses_for_stmt to determine whether to look at
153 virtual and/or real operands while computing def-use chains. */
156 compute_immediate_uses (int flags, bool (*calc_for)(tree))
159 block_stmt_iterator si;
165 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
167 if (is_gimple_reg (PHI_RESULT (phi)))
169 if (!(flags & TDFA_USE_OPS))
174 if (!(flags & TDFA_USE_VOPS))
178 compute_immediate_uses_for_phi (phi, calc_for);
181 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
183 tree stmt = bsi_stmt (si);
184 get_stmt_operands (stmt);
185 compute_immediate_uses_for_stmt (stmt, flags, calc_for);
191 /* Invalidates dataflow information for a statement STMT. */
194 free_df_for_stmt (tree stmt)
198 if (TREE_CODE (stmt) == PHI_NODE)
202 stmt_ann_t ann = stmt_ann (stmt);
213 /* If we have a varray of immediate uses, then go ahead and release
215 if ((*df)->immediate_uses)
216 ggc_free ((*df)->immediate_uses);
218 /* Similarly for the main dataflow structure. */
224 /* Invalidate dataflow information for the whole function. */
230 block_stmt_iterator si;
236 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
237 free_df_for_stmt (phi);
239 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
241 tree stmt = bsi_stmt (si);
242 free_df_for_stmt (stmt);
248 /* Helper for compute_immediate_uses. Check all the USE and/or VUSE
249 operands in phi node PHI and add a def-use edge between their
250 defining statement and PHI. CALC_FOR is as in
251 compute_immediate_uses.
253 PHI nodes are easy, we only need to look at their arguments. */
256 compute_immediate_uses_for_phi (tree phi, bool (*calc_for)(tree))
260 gcc_assert (TREE_CODE (phi) == PHI_NODE);
262 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
264 tree arg = PHI_ARG_DEF (phi, i);
266 if (TREE_CODE (arg) == SSA_NAME && (!calc_for || calc_for (arg)))
268 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (PHI_ARG_DEF (phi, i));
269 if (!IS_EMPTY_STMT (imm_rdef_stmt))
270 add_immediate_use (imm_rdef_stmt, phi);
276 /* Another helper for compute_immediate_uses. Depending on the value
277 of FLAGS, check all the USE and/or VUSE operands in STMT and add a
278 def-use edge between their defining statement and STMT. CALC_FOR
279 is as in compute_immediate_uses. */
282 compute_immediate_uses_for_stmt (tree stmt, int flags, bool (*calc_for)(tree))
287 /* PHI nodes are handled elsewhere. */
288 gcc_assert (TREE_CODE (stmt) != PHI_NODE);
290 /* Look at USE_OPS or VUSE_OPS according to FLAGS. */
291 if (flags & TDFA_USE_OPS)
293 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
295 tree imm_stmt = SSA_NAME_DEF_STMT (use);
296 if (!IS_EMPTY_STMT (imm_stmt) && (!calc_for || calc_for (use)))
297 add_immediate_use (imm_stmt, stmt);
301 if (flags & TDFA_USE_VOPS)
303 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_VIRTUAL_USES)
305 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (use);
306 if (!IS_EMPTY_STMT (imm_rdef_stmt) && (!calc_for || calc_for (use)))
307 add_immediate_use (imm_rdef_stmt, stmt);
313 /* Add statement USE_STMT to the list of statements that use definitions
317 add_immediate_use (tree stmt, tree use_stmt)
319 struct dataflow_d **df;
321 if (TREE_CODE (stmt) == PHI_NODE)
325 stmt_ann_t ann = get_stmt_ann (stmt);
331 *df = ggc_alloc (sizeof (struct dataflow_d));
332 memset ((void *) *df, 0, sizeof (struct dataflow_d));
333 (*df)->uses[0] = use_stmt;
339 (*df)->uses[1] = use_stmt;
343 if ((*df)->immediate_uses == NULL)
344 VARRAY_TREE_INIT ((*df)->immediate_uses, 4, "immediate_uses");
346 VARRAY_PUSH_TREE ((*df)->immediate_uses, use_stmt);
350 /* If the immediate use of USE points to OLD, then redirect it to NEW. */
353 redirect_immediate_use (tree use, tree old, tree new)
355 tree imm_stmt = SSA_NAME_DEF_STMT (use);
356 struct dataflow_d *df = get_immediate_uses (imm_stmt);
357 unsigned int num_uses = num_immediate_uses (df);
360 for (i = 0; i < num_uses; i++)
362 if (immediate_use (df, i) == old)
364 if (i == 0 || i == 1)
367 VARRAY_TREE (df->immediate_uses, i - 2) = new;
373 /* Redirect all immediate uses for operands in OLD so that they point
374 to NEW. This routine should have no knowledge of how immediate
378 redirect_immediate_uses (tree old, tree new)
383 FOR_EACH_SSA_TREE_OPERAND (val, old, iter, SSA_OP_ALL_USES)
384 redirect_immediate_use (val, old, new);
388 /*---------------------------------------------------------------------------
390 ---------------------------------------------------------------------------*/
391 /* Create a new annotation for a _DECL node T. */
394 create_var_ann (tree t)
399 gcc_assert (DECL_P (t));
400 gcc_assert (!t->common.ann || t->common.ann->common.type == VAR_ANN);
402 ann = ggc_alloc (sizeof (*ann));
403 memset ((void *) ann, 0, sizeof (*ann));
405 ann->common.type = VAR_ANN;
407 t->common.ann = (tree_ann_t) ann;
413 /* Create a new annotation for a statement node T. */
416 create_stmt_ann (tree t)
420 gcc_assert (is_gimple_stmt (t));
421 gcc_assert (!t->common.ann || t->common.ann->common.type == STMT_ANN);
423 ann = ggc_alloc (sizeof (*ann));
424 memset ((void *) ann, 0, sizeof (*ann));
426 ann->common.type = STMT_ANN;
428 /* Since we just created the annotation, mark the statement modified. */
429 ann->modified = true;
431 t->common.ann = (tree_ann_t) ann;
437 /* Create a new annotation for a tree T. */
440 create_tree_ann (tree t)
445 gcc_assert (!t->common.ann || t->common.ann->common.type == TREE_ANN_COMMON);
447 ann = ggc_alloc (sizeof (*ann));
448 memset ((void *) ann, 0, sizeof (*ann));
450 ann->common.type = TREE_ANN_COMMON;
456 /* Build a temporary. Make sure and register it to be renamed. */
459 make_rename_temp (tree type, const char *prefix)
461 tree t = create_tmp_var (type, prefix);
464 add_referenced_tmp_var (t);
465 bitmap_set_bit (vars_to_rename, var_ann (t)->uid);
472 /*---------------------------------------------------------------------------
474 ---------------------------------------------------------------------------*/
475 /* Dump the list of all the referenced variables in the current function to
479 dump_referenced_vars (FILE *file)
483 fprintf (file, "\nReferenced variables in %s: %u\n\n",
484 get_name (current_function_decl), (unsigned) num_referenced_vars);
486 for (i = 0; i < num_referenced_vars; i++)
488 tree var = referenced_var (i);
489 fprintf (file, "Variable: ");
490 dump_variable (file, var);
491 fprintf (file, "\n");
496 /* Dump the list of all the referenced variables to stderr. */
499 debug_referenced_vars (void)
501 dump_referenced_vars (stderr);
505 /* Dump variable VAR and its may-aliases to FILE. */
508 dump_variable (FILE *file, tree var)
512 if (TREE_CODE (var) == SSA_NAME)
514 if (POINTER_TYPE_P (TREE_TYPE (var)))
515 dump_points_to_info_for (file, var);
516 var = SSA_NAME_VAR (var);
519 if (var == NULL_TREE)
521 fprintf (file, "<nil>");
525 print_generic_expr (file, var, dump_flags);
529 fprintf (file, ", UID %u", (unsigned) ann->uid);
531 if (ann->type_mem_tag)
533 fprintf (file, ", type memory tag: ");
534 print_generic_expr (file, ann->type_mem_tag, dump_flags);
537 if (ann->is_alias_tag)
538 fprintf (file, ", is an alias tag");
540 if (TREE_ADDRESSABLE (var))
541 fprintf (file, ", is addressable");
543 if (is_global_var (var))
544 fprintf (file, ", is global");
546 if (is_call_clobbered (var))
547 fprintf (file, ", call clobbered");
549 if (ann->default_def)
551 fprintf (file, ", default def: ");
552 print_generic_expr (file, ann->default_def, dump_flags);
555 if (ann->may_aliases)
557 fprintf (file, ", may aliases: ");
558 dump_may_aliases_for (file, var);
561 fprintf (file, "\n");
565 /* Dump variable VAR and its may-aliases to stderr. */
568 debug_variable (tree var)
570 dump_variable (stderr, var);
574 /* Dump def-use edges on FILE. */
577 dump_immediate_uses (FILE *file)
580 block_stmt_iterator si;
582 = lang_hooks.decl_printable_name (current_function_decl, 2);
584 fprintf (file, "\nDef-use edges for function %s\n", funcname);
590 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
591 dump_immediate_uses_for (file, phi);
593 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
594 dump_immediate_uses_for (file, bsi_stmt (si));
597 fprintf (file, "\n");
601 /* Dump def-use edges on stderr. */
604 debug_immediate_uses (void)
606 dump_immediate_uses (stderr);
610 /* Dump all immediate uses for STMT on FILE. */
613 dump_immediate_uses_for (FILE *file, tree stmt)
615 dataflow_t df = get_immediate_uses (stmt);
616 int num_imm_uses = num_immediate_uses (df);
618 if (num_imm_uses > 0)
622 fprintf (file, "-> ");
623 print_generic_stmt (file, stmt, TDF_SLIM);
624 fprintf (file, "\n");
626 for (i = 0; i < num_imm_uses; i++)
628 fprintf (file, "\t");
629 print_generic_stmt (file, immediate_use (df, i), TDF_SLIM);
630 fprintf (file, "\n");
633 fprintf (file, "\n");
638 /* Dump immediate uses for STMT on stderr. */
641 debug_immediate_uses_for (tree stmt)
643 dump_immediate_uses_for (stderr, stmt);
647 /* Dump various DFA statistics to FILE. */
650 dump_dfa_stats (FILE *file)
652 struct dfa_stats_d dfa_stats;
654 unsigned long size, total = 0;
655 const char * const fmt_str = "%-30s%-13s%12s\n";
656 const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
657 const char * const fmt_str_3 = "%-43s%11lu%c\n";
659 = lang_hooks.decl_printable_name (current_function_decl, 2);
661 collect_dfa_stats (&dfa_stats);
663 fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
665 fprintf (file, "---------------------------------------------------------\n");
666 fprintf (file, fmt_str, "", " Number of ", "Memory");
667 fprintf (file, fmt_str, "", " instances ", "used ");
668 fprintf (file, "---------------------------------------------------------\n");
670 size = num_referenced_vars * sizeof (tree);
672 fprintf (file, fmt_str_1, "Referenced variables", num_referenced_vars,
673 SCALE (size), LABEL (size));
675 size = dfa_stats.num_stmt_anns * sizeof (struct stmt_ann_d);
677 fprintf (file, fmt_str_1, "Statements annotated", dfa_stats.num_stmt_anns,
678 SCALE (size), LABEL (size));
680 size = dfa_stats.num_var_anns * sizeof (struct var_ann_d);
682 fprintf (file, fmt_str_1, "Variables annotated", dfa_stats.num_var_anns,
683 SCALE (size), LABEL (size));
685 size = dfa_stats.num_uses * sizeof (tree *);
687 fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
688 SCALE (size), LABEL (size));
690 size = dfa_stats.num_defs * sizeof (tree *);
692 fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
693 SCALE (size), LABEL (size));
695 size = dfa_stats.num_vuses * sizeof (tree *);
697 fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
698 SCALE (size), LABEL (size));
700 size = dfa_stats.num_v_may_defs * sizeof (tree *);
702 fprintf (file, fmt_str_1, "V_MAY_DEF operands", dfa_stats.num_v_may_defs,
703 SCALE (size), LABEL (size));
705 size = dfa_stats.num_v_must_defs * sizeof (tree *);
707 fprintf (file, fmt_str_1, "V_MUST_DEF operands", dfa_stats.num_v_must_defs,
708 SCALE (size), LABEL (size));
710 size = dfa_stats.num_phis * sizeof (struct tree_phi_node);
712 fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
713 SCALE (size), LABEL (size));
715 size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
717 fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
718 SCALE (size), LABEL (size));
720 fprintf (file, "---------------------------------------------------------\n");
721 fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
723 fprintf (file, "---------------------------------------------------------\n");
724 fprintf (file, "\n");
726 if (dfa_stats.num_phis)
727 fprintf (file, "Average number of arguments per PHI node: %.1f (max: %d)\n",
728 (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
729 dfa_stats.max_num_phi_args);
731 fprintf (file, "\n");
735 /* Dump DFA statistics on stderr. */
738 debug_dfa_stats (void)
740 dump_dfa_stats (stderr);
744 /* Collect DFA statistics and store them in the structure pointed by
748 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p)
752 block_stmt_iterator i;
754 gcc_assert (dfa_stats_p);
756 memset ((void *)dfa_stats_p, 0, sizeof (struct dfa_stats_d));
758 /* Walk all the trees in the function counting references. Start at
759 basic block 0, but don't stop at block boundaries. */
760 htab = htab_create (30, htab_hash_pointer, htab_eq_pointer, NULL);
762 for (i = bsi_start (BASIC_BLOCK (0)); !bsi_end_p (i); bsi_next (&i))
763 walk_tree (bsi_stmt_ptr (i), collect_dfa_stats_r, (void *) dfa_stats_p,
771 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
773 dfa_stats_p->num_phis++;
774 dfa_stats_p->num_phi_args += PHI_NUM_ARGS (phi);
775 if (PHI_NUM_ARGS (phi) > dfa_stats_p->max_num_phi_args)
776 dfa_stats_p->max_num_phi_args = PHI_NUM_ARGS (phi);
782 /* Callback for walk_tree to collect DFA statistics for a tree and its
786 collect_dfa_stats_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
790 struct dfa_stats_d *dfa_stats_p = (struct dfa_stats_d *)data;
794 switch (ann_type (t->common.ann))
798 stmt_ann_t ann = (stmt_ann_t) t->common.ann;
799 dfa_stats_p->num_stmt_anns++;
800 dfa_stats_p->num_defs += NUM_DEFS (DEF_OPS (ann));
801 dfa_stats_p->num_uses += NUM_USES (USE_OPS (ann));
802 dfa_stats_p->num_v_may_defs +=
803 NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann));
804 dfa_stats_p->num_vuses += NUM_VUSES (VUSE_OPS (ann));
805 dfa_stats_p->num_v_must_defs +=
806 NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann));
811 dfa_stats_p->num_var_anns++;
823 /*---------------------------------------------------------------------------
824 Miscellaneous helpers
825 ---------------------------------------------------------------------------*/
826 /* Callback for walk_tree. Used to collect variables referenced in
830 find_vars_r (tree *tp, int *walk_subtrees, void *data)
832 struct walk_state *walk_state = (struct walk_state *) data;
834 /* If T is a regular variable that the optimizers are interested
835 in, add it to the list of variables. */
837 add_referenced_var (*tp, walk_state);
839 /* Type, _DECL and constant nodes have no interesting children.
841 else if (DECL_P (*tp)
843 || TREE_CODE_CLASS (TREE_CODE (*tp)) == 'c')
850 /* Add VAR to the list of dereferenced variables.
852 WALK_STATE contains a hash table used to avoid adding the same
853 variable more than once. Note that this function assumes that
854 VAR is a valid SSA variable. If WALK_STATE is NULL, no
855 duplicate checking is done. */
858 add_referenced_var (tree var, struct walk_state *walk_state)
863 v_ann = get_var_ann (var);
866 slot = htab_find_slot (walk_state->vars_found, (void *) var, INSERT);
870 if (slot == NULL || *slot == NULL)
872 /* This is the first time we find this variable, add it to the
873 REFERENCED_VARS array and annotate it with attributes that are
874 intrinsic to the variable. */
876 *slot = (void *) var;
877 v_ann->uid = num_referenced_vars;
878 VARRAY_PUSH_TREE (referenced_vars, var);
880 /* Global variables are always call-clobbered. */
881 if (is_global_var (var))
882 mark_call_clobbered (var);
884 /* If an initialized global variable then register the initializer
886 if (POINTER_TYPE_P (TREE_TYPE (var))
887 && TREE_READONLY (var)
888 && DECL_INITIAL (var)
889 && TREE_CODE (DECL_INITIAL (var)) == ADDR_EXPR)
890 walk_tree (&DECL_INITIAL (var), find_vars_r, walk_state, 0);
895 /* Return the virtual variable associated to the non-scalar variable VAR. */
898 get_virtual_var (tree var)
902 if (TREE_CODE (var) == SSA_NAME)
903 var = SSA_NAME_VAR (var);
905 while (TREE_CODE (var) == REALPART_EXPR || TREE_CODE (var) == IMAGPART_EXPR
906 || handled_component_p (var))
907 var = TREE_OPERAND (var, 0);
909 /* Treating GIMPLE registers as virtual variables makes no sense.
910 Also complain if we couldn't extract a _DECL out of the original
912 gcc_assert (SSA_VAR_P (var));
913 gcc_assert (!is_gimple_reg (var));
918 /* Add a temporary variable to REFERENCED_VARS. This is similar to
919 add_referenced_var, but is used by passes that need to add new temps to
920 the REFERENCED_VARS array after the program has been scanned for
921 variables. The variable will just receive a new UID and be added
922 to the REFERENCED_VARS array without checking for duplicates. */
925 add_referenced_tmp_var (tree var)
927 add_referenced_var (var, NULL);
931 /* Add all the non-SSA variables found in STMT's operands to the bitmap
935 mark_new_vars_to_rename (tree stmt, bitmap vars_to_rename)
939 bitmap vars_in_vops_to_rename;
940 bool found_exposed_symbol = false;
941 int v_may_defs_before, v_may_defs_after;
942 int v_must_defs_before, v_must_defs_after;
944 vars_in_vops_to_rename = BITMAP_XMALLOC ();
946 /* Before re-scanning the statement for operands, mark the existing
947 virtual operands to be renamed again. We do this because when new
948 symbols are exposed, the virtual operands that were here before due to
949 aliasing will probably be removed by the call to get_stmt_operand.
950 Therefore, we need to flag them to be renamed beforehand.
952 We flag them in a separate bitmap because we don't really want to
953 rename them if there are not any newly exposed symbols in the
954 statement operands. */
955 v_may_defs_before = NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt));
956 v_must_defs_before = NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt));
958 FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter,
959 SSA_OP_VMAYDEF | SSA_OP_VUSE | SSA_OP_VMUSTDEF)
962 val = SSA_NAME_VAR (val);
963 bitmap_set_bit (vars_in_vops_to_rename, var_ann (val)->uid);
966 /* Now force an operand re-scan on the statement and mark any newly
967 exposed variables. */
969 get_stmt_operands (stmt);
971 v_may_defs_after = NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt));
972 v_must_defs_after = NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt));
974 FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter,
975 SSA_OP_VMAYDEF | SSA_OP_VUSE | SSA_OP_VMUSTDEF)
980 found_exposed_symbol = true;
981 bitmap_set_bit (vars_to_rename, var_ann (val)->uid);
985 /* If we found any newly exposed symbols, or if there are fewer VDEF
986 operands in the statement, add the variables we had set in
987 VARS_IN_VOPS_TO_RENAME to VARS_TO_RENAME. We need to check for
988 vanishing VDEFs because in those cases, the names that were formerly
989 generated by this statement are not going to be available anymore. */
990 if (found_exposed_symbol
991 || v_may_defs_before > v_may_defs_after
992 || v_must_defs_before > v_must_defs_after)
993 bitmap_a_or_b (vars_to_rename, vars_to_rename, vars_in_vops_to_rename);
995 BITMAP_XFREE (vars_in_vops_to_rename);