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-alias-common.h"
46 #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 vars_found = htab_create (50, htab_hash_pointer, htab_eq_pointer, NULL);
112 memset (&walk_state, 0, sizeof (walk_state));
113 walk_state.vars_found = vars_found;
116 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
118 tree *stmt_p = bsi_stmt_ptr (si);
119 walk_tree (stmt_p, find_vars_r, &walk_state, NULL);
122 htab_delete (vars_found);
125 struct tree_opt_pass pass_referenced_vars =
129 find_referenced_vars, /* execute */
132 0, /* static_pass_number */
134 PROP_gimple_leh | PROP_cfg, /* properties_required */
135 PROP_referenced_vars, /* properties_provided */
136 0, /* properties_destroyed */
137 0, /* todo_flags_start */
138 0, /* todo_flags_finish */
143 /* Compute immediate uses.
145 CALC_FOR is an optional function pointer which indicates whether
146 immediate uses information should be calculated for a given SSA
147 variable. If NULL, then information is computed for all
150 FLAGS is one of {TDFA_USE_OPS, TDFA_USE_VOPS}. It is used by
151 compute_immediate_uses_for_stmt to determine whether to look at
152 virtual and/or real operands while computing def-use chains. */
155 compute_immediate_uses (int flags, bool (*calc_for)(tree))
158 block_stmt_iterator si;
164 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
166 if (is_gimple_reg (PHI_RESULT (phi)))
168 if (!(flags & TDFA_USE_OPS))
173 if (!(flags & TDFA_USE_VOPS))
177 compute_immediate_uses_for_phi (phi, calc_for);
180 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
182 tree stmt = bsi_stmt (si);
183 get_stmt_operands (stmt);
184 compute_immediate_uses_for_stmt (stmt, flags, calc_for);
190 /* Invalidates dataflow information for a statement STMT. */
193 free_df_for_stmt (tree stmt)
195 stmt_ann_t ann = stmt_ann (stmt);
199 /* If we have a varray of immediate uses, then go ahead and release
201 if (ann->df->immediate_uses)
202 ggc_free (ann->df->immediate_uses);
204 /* Similarly for the main dataflow structure. */
211 /* Invalidate dataflow information for the whole function. */
217 block_stmt_iterator si;
223 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
224 free_df_for_stmt (phi);
226 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
228 tree stmt = bsi_stmt (si);
229 free_df_for_stmt (stmt);
235 /* Helper for compute_immediate_uses. Check all the USE and/or VUSE
236 operands in phi node PHI and add a def-use edge between their
237 defining statement and PHI. CALC_FOR is as in
238 compute_immediate_uses.
240 PHI nodes are easy, we only need to look at their arguments. */
243 compute_immediate_uses_for_phi (tree phi, bool (*calc_for)(tree))
247 #ifdef ENABLE_CHECKING
248 if (TREE_CODE (phi) != PHI_NODE)
252 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
254 tree arg = PHI_ARG_DEF (phi, i);
256 if (TREE_CODE (arg) == SSA_NAME && (!calc_for || calc_for (arg)))
258 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (PHI_ARG_DEF (phi, i));
259 if (!IS_EMPTY_STMT (imm_rdef_stmt))
260 add_immediate_use (imm_rdef_stmt, phi);
266 /* Another helper for compute_immediate_uses. Depending on the value
267 of FLAGS, check all the USE and/or VUSE operands in STMT and add a
268 def-use edge between their defining statement and STMT. CALC_FOR
269 is as in compute_immediate_uses. */
272 compute_immediate_uses_for_stmt (tree stmt, int flags, bool (*calc_for)(tree))
277 #ifdef ENABLE_CHECKING
278 /* PHI nodes are handled elsewhere. */
279 if (TREE_CODE (stmt) == PHI_NODE)
283 /* Look at USE_OPS or VUSE_OPS according to FLAGS. */
284 if (flags & TDFA_USE_OPS)
286 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
288 tree imm_stmt = SSA_NAME_DEF_STMT (use);
289 if (!IS_EMPTY_STMT (imm_stmt) && (!calc_for || calc_for (use)))
290 add_immediate_use (imm_stmt, stmt);
294 if (flags & TDFA_USE_VOPS)
296 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_VIRTUAL_USES)
298 tree imm_rdef_stmt = SSA_NAME_DEF_STMT (use);
299 if (!IS_EMPTY_STMT (imm_rdef_stmt) && (!calc_for || calc_for (use)))
300 add_immediate_use (imm_rdef_stmt, stmt);
306 /* Add statement USE_STMT to the list of statements that use definitions
310 add_immediate_use (tree stmt, tree use_stmt)
312 stmt_ann_t ann = get_stmt_ann (stmt);
313 struct dataflow_d *df;
318 df = ann->df = ggc_alloc (sizeof (struct dataflow_d));
319 memset ((void *) df, 0, sizeof (struct dataflow_d));
320 df->uses[0] = use_stmt;
326 df->uses[1] = use_stmt;
330 if (ann->df->immediate_uses == NULL)
331 VARRAY_TREE_INIT (ann->df->immediate_uses, 4, "immediate_uses");
333 VARRAY_PUSH_TREE (ann->df->immediate_uses, use_stmt);
337 /* If the immediate use of USE points to OLD, then redirect it to NEW. */
340 redirect_immediate_use (tree use, tree old, tree new)
342 tree imm_stmt = SSA_NAME_DEF_STMT (use);
343 struct dataflow_d *df = get_stmt_ann (imm_stmt)->df;
344 unsigned int num_uses = num_immediate_uses (df);
347 for (i = 0; i < num_uses; i++)
349 if (immediate_use (df, i) == old)
351 if (i == 0 || i == 1)
354 VARRAY_TREE (df->immediate_uses, i - 2) = new;
360 /* Redirect all immediate uses for operands in OLD so that they point
361 to NEW. This routine should have no knowledge of how immediate
365 redirect_immediate_uses (tree old, tree new)
370 FOR_EACH_SSA_TREE_OPERAND (val, old, iter, SSA_OP_ALL_USES)
371 redirect_immediate_use (val, old, new);
375 /*---------------------------------------------------------------------------
377 ---------------------------------------------------------------------------*/
378 /* Create a new annotation for a _DECL node T. */
381 create_var_ann (tree t)
385 #if defined ENABLE_CHECKING
389 && t->common.ann->common.type != VAR_ANN))
393 ann = ggc_alloc (sizeof (*ann));
394 memset ((void *) ann, 0, sizeof (*ann));
396 ann->common.type = VAR_ANN;
398 t->common.ann = (tree_ann_t) ann;
404 /* Create a new annotation for a statement node T. */
407 create_stmt_ann (tree t)
411 #if defined ENABLE_CHECKING
412 if ((!is_gimple_stmt (t))
414 && t->common.ann->common.type != STMT_ANN))
418 ann = ggc_alloc (sizeof (*ann));
419 memset ((void *) ann, 0, sizeof (*ann));
421 ann->common.type = STMT_ANN;
423 /* Since we just created the annotation, mark the statement modified. */
424 ann->modified = true;
426 t->common.ann = (tree_ann_t) ann;
432 /* Create a new annotation for a tree T. */
435 create_tree_ann (tree t)
439 #if defined ENABLE_CHECKING
442 && t->common.ann->common.type != TREE_ANN_COMMON))
446 ann = ggc_alloc (sizeof (*ann));
447 memset ((void *) ann, 0, sizeof (*ann));
449 ann->common.type = TREE_ANN_COMMON;
455 /* Build a temporary. Make sure and register it to be renamed. */
458 make_rename_temp (tree type, const char *prefix)
460 tree t = create_tmp_var (type, prefix);
463 add_referenced_tmp_var (t);
464 bitmap_set_bit (vars_to_rename, var_ann (t)->uid);
471 /*---------------------------------------------------------------------------
473 ---------------------------------------------------------------------------*/
474 /* Dump the list of all the referenced variables in the current function to
478 dump_referenced_vars (FILE *file)
482 fprintf (file, "\nReferenced variables in %s: %u\n\n",
483 get_name (current_function_decl), (unsigned) num_referenced_vars);
485 for (i = 0; i < num_referenced_vars; i++)
487 tree var = referenced_var (i);
488 fprintf (file, "Variable: ");
489 dump_variable (file, var);
490 fprintf (file, "\n");
495 /* Dump the list of all the referenced variables to stderr. */
498 debug_referenced_vars (void)
500 dump_referenced_vars (stderr);
504 /* Dump variable VAR and its may-aliases to FILE. */
507 dump_variable (FILE *file, tree var)
511 if (TREE_CODE (var) == SSA_NAME)
513 if (POINTER_TYPE_P (TREE_TYPE (var)))
514 dump_points_to_info_for (file, var);
515 var = SSA_NAME_VAR (var);
518 if (var == NULL_TREE)
520 fprintf (file, "<nil>");
524 print_generic_expr (file, var, dump_flags);
528 fprintf (file, ", UID %u", (unsigned) ann->uid);
530 if (ann->type_mem_tag)
532 fprintf (file, ", type memory tag: ");
533 print_generic_expr (file, ann->type_mem_tag, dump_flags);
536 if (ann->is_alias_tag)
537 fprintf (file, ", is an alias tag");
539 if (TREE_ADDRESSABLE (var))
540 fprintf (file, ", is addressable");
542 if (is_global_var (var))
543 fprintf (file, ", is global");
545 if (is_call_clobbered (var))
546 fprintf (file, ", call clobbered");
548 if (ann->default_def)
550 fprintf (file, ", default def: ");
551 print_generic_expr (file, ann->default_def, dump_flags);
554 if (ann->may_aliases)
556 fprintf (file, ", may aliases: ");
557 dump_may_aliases_for (file, var);
560 fprintf (file, "\n");
564 /* Dump variable VAR and its may-aliases to stderr. */
567 debug_variable (tree var)
569 dump_variable (stderr, var);
573 /* Dump def-use edges on FILE. */
576 dump_immediate_uses (FILE *file)
579 block_stmt_iterator si;
581 = lang_hooks.decl_printable_name (current_function_decl, 2);
583 fprintf (file, "\nDef-use edges for function %s\n", funcname);
589 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
590 dump_immediate_uses_for (file, phi);
592 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
593 dump_immediate_uses_for (file, bsi_stmt (si));
596 fprintf (file, "\n");
600 /* Dump def-use edges on stderr. */
603 debug_immediate_uses (void)
605 dump_immediate_uses (stderr);
609 /* Dump all immediate uses for STMT on FILE. */
612 dump_immediate_uses_for (FILE *file, tree stmt)
614 dataflow_t df = get_immediate_uses (stmt);
615 int num_imm_uses = num_immediate_uses (df);
617 if (num_imm_uses > 0)
621 fprintf (file, "-> ");
622 print_generic_stmt (file, stmt, TDF_SLIM);
623 fprintf (file, "\n");
625 for (i = 0; i < num_imm_uses; i++)
627 fprintf (file, "\t");
628 print_generic_stmt (file, immediate_use (df, i), TDF_SLIM);
629 fprintf (file, "\n");
632 fprintf (file, "\n");
637 /* Dump immediate uses for STMT on stderr. */
640 debug_immediate_uses_for (tree stmt)
642 dump_immediate_uses_for (stderr, stmt);
646 /* Dump various DFA statistics to FILE. */
649 dump_dfa_stats (FILE *file)
651 struct dfa_stats_d dfa_stats;
653 unsigned long size, total = 0;
654 const char * const fmt_str = "%-30s%-13s%12s\n";
655 const char * const fmt_str_1 = "%-30s%13lu%11lu%c\n";
656 const char * const fmt_str_3 = "%-43s%11lu%c\n";
658 = lang_hooks.decl_printable_name (current_function_decl, 2);
660 collect_dfa_stats (&dfa_stats);
662 fprintf (file, "\nDFA Statistics for %s\n\n", funcname);
664 fprintf (file, "---------------------------------------------------------\n");
665 fprintf (file, fmt_str, "", " Number of ", "Memory");
666 fprintf (file, fmt_str, "", " instances ", "used ");
667 fprintf (file, "---------------------------------------------------------\n");
669 size = num_referenced_vars * sizeof (tree);
671 fprintf (file, fmt_str_1, "Referenced variables", num_referenced_vars,
672 SCALE (size), LABEL (size));
674 size = dfa_stats.num_stmt_anns * sizeof (struct stmt_ann_d);
676 fprintf (file, fmt_str_1, "Statements annotated", dfa_stats.num_stmt_anns,
677 SCALE (size), LABEL (size));
679 size = dfa_stats.num_var_anns * sizeof (struct var_ann_d);
681 fprintf (file, fmt_str_1, "Variables annotated", dfa_stats.num_var_anns,
682 SCALE (size), LABEL (size));
684 size = dfa_stats.num_uses * sizeof (tree *);
686 fprintf (file, fmt_str_1, "USE operands", dfa_stats.num_uses,
687 SCALE (size), LABEL (size));
689 size = dfa_stats.num_defs * sizeof (tree *);
691 fprintf (file, fmt_str_1, "DEF operands", dfa_stats.num_defs,
692 SCALE (size), LABEL (size));
694 size = dfa_stats.num_vuses * sizeof (tree *);
696 fprintf (file, fmt_str_1, "VUSE operands", dfa_stats.num_vuses,
697 SCALE (size), LABEL (size));
699 size = dfa_stats.num_v_may_defs * sizeof (tree *);
701 fprintf (file, fmt_str_1, "V_MAY_DEF operands", dfa_stats.num_v_may_defs,
702 SCALE (size), LABEL (size));
704 size = dfa_stats.num_v_must_defs * sizeof (tree *);
706 fprintf (file, fmt_str_1, "V_MUST_DEF operands", dfa_stats.num_v_must_defs,
707 SCALE (size), LABEL (size));
709 size = dfa_stats.num_phis * sizeof (struct tree_phi_node);
711 fprintf (file, fmt_str_1, "PHI nodes", dfa_stats.num_phis,
712 SCALE (size), LABEL (size));
714 size = dfa_stats.num_phi_args * sizeof (struct phi_arg_d);
716 fprintf (file, fmt_str_1, "PHI arguments", dfa_stats.num_phi_args,
717 SCALE (size), LABEL (size));
719 fprintf (file, "---------------------------------------------------------\n");
720 fprintf (file, fmt_str_3, "Total memory used by DFA/SSA data", SCALE (total),
722 fprintf (file, "---------------------------------------------------------\n");
723 fprintf (file, "\n");
725 if (dfa_stats.num_phis)
726 fprintf (file, "Average number of arguments per PHI node: %.1f (max: %d)\n",
727 (float) dfa_stats.num_phi_args / (float) dfa_stats.num_phis,
728 dfa_stats.max_num_phi_args);
730 fprintf (file, "\n");
734 /* Dump DFA statistics on stderr. */
737 debug_dfa_stats (void)
739 dump_dfa_stats (stderr);
743 /* Collect DFA statistics and store them in the structure pointed by
747 collect_dfa_stats (struct dfa_stats_d *dfa_stats_p)
751 block_stmt_iterator i;
753 if (dfa_stats_p == NULL)
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 #ifdef ENABLE_CHECKING
910 /* Treating GIMPLE registers as virtual variables makes no sense.
911 Also complain if we couldn't extract a _DECL out of the original
914 || is_gimple_reg (var))
921 /* Add a temporary variable to REFERENCED_VARS. This is similar to
922 add_referenced_var, but is used by passes that need to add new temps to
923 the REFERENCED_VARS array after the program has been scanned for
924 variables. The variable will just receive a new UID and be added
925 to the REFERENCED_VARS array without checking for duplicates. */
928 add_referenced_tmp_var (tree var)
930 add_referenced_var (var, NULL);
934 /* Add all the non-SSA variables found in STMT's operands to the bitmap
938 mark_new_vars_to_rename (tree stmt, bitmap vars_to_rename)
942 bitmap vars_in_vops_to_rename;
943 bool found_exposed_symbol = false;
944 int v_may_defs_before, v_may_defs_after;
945 int v_must_defs_before, v_must_defs_after;
947 vars_in_vops_to_rename = BITMAP_XMALLOC ();
949 /* Before re-scanning the statement for operands, mark the existing
950 virtual operands to be renamed again. We do this because when new
951 symbols are exposed, the virtual operands that were here before due to
952 aliasing will probably be removed by the call to get_stmt_operand.
953 Therefore, we need to flag them to be renamed beforehand.
955 We flag them in a separate bitmap because we don't really want to
956 rename them if there are not any newly exposed symbols in the
957 statement operands. */
958 v_may_defs_before = NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt));
959 v_must_defs_before = NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt));
961 FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter,
962 SSA_OP_VMAYDEF | SSA_OP_VUSE | SSA_OP_VMUSTDEF)
965 val = SSA_NAME_VAR (val);
966 bitmap_set_bit (vars_in_vops_to_rename, var_ann (val)->uid);
969 /* Now force an operand re-scan on the statement and mark any newly
970 exposed variables. */
972 get_stmt_operands (stmt);
974 v_may_defs_after = NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt));
975 v_must_defs_after = NUM_V_MUST_DEFS (STMT_V_MUST_DEF_OPS (stmt));
977 FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter,
978 SSA_OP_VMAYDEF | SSA_OP_VUSE | SSA_OP_VMUSTDEF)
983 found_exposed_symbol = true;
984 bitmap_set_bit (vars_to_rename, var_ann (val)->uid);
988 /* If we found any newly exposed symbols, or if there are fewer VDEF
989 operands in the statement, add the variables we had set in
990 VARS_IN_VOPS_TO_RENAME to VARS_TO_RENAME. We need to check for
991 vanishing VDEFs because in those cases, the names that were formerly
992 generated by this statement are not going to be available anymore. */
993 if (found_exposed_symbol
994 || v_may_defs_before > v_may_defs_after
995 || v_must_defs_before > v_must_defs_after)
996 bitmap_a_or_b (vars_to_rename, vars_to_rename, vars_in_vops_to_rename);
998 BITMAP_XFREE (vars_in_vops_to_rename);