1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
36 #include "langhooks.h"
37 #include "diagnostic.h"
38 #include "tree-flow.h"
40 #include "tree-dump.h"
41 #include "tree-pass.h"
45 #include "cfglayout.h"
46 #include "tree-ssa-propagate.h"
47 #include "value-prof.h"
48 #include "pointer-set.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity = 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 static struct pointer_map_t *edge_to_cases;
76 long num_merged_labels;
79 static struct cfg_stats_d cfg_stats;
81 /* Nonzero if we found a computed goto while building basic blocks. */
82 static bool found_computed_goto;
84 /* Basic blocks and flowgraphs. */
85 static basic_block create_bb (void *, void *, basic_block);
86 static void make_blocks (tree);
87 static void factor_computed_gotos (void);
90 static void make_edges (void);
91 static void make_cond_expr_edges (basic_block);
92 static void make_switch_expr_edges (basic_block);
93 static void make_goto_expr_edges (basic_block);
94 static edge tree_redirect_edge_and_branch (edge, basic_block);
95 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
96 static unsigned int split_critical_edges (void);
98 /* Various helpers. */
99 static inline bool stmt_starts_bb_p (tree, tree);
100 static int tree_verify_flow_info (void);
101 static void tree_make_forwarder_block (edge);
102 static void tree_cfg2vcg (FILE *);
103 static inline void change_bb_for_stmt (tree t, basic_block bb);
105 /* Flowgraph optimization and cleanup. */
106 static void tree_merge_blocks (basic_block, basic_block);
107 static bool tree_can_merge_blocks_p (basic_block, basic_block);
108 static void remove_bb (basic_block);
109 static edge find_taken_edge_computed_goto (basic_block, tree);
110 static edge find_taken_edge_cond_expr (basic_block, tree);
111 static edge find_taken_edge_switch_expr (basic_block, tree);
112 static tree find_case_label_for_value (tree, tree);
115 init_empty_tree_cfg (void)
117 /* Initialize the basic block array. */
119 profile_status = PROFILE_ABSENT;
120 n_basic_blocks = NUM_FIXED_BLOCKS;
121 last_basic_block = NUM_FIXED_BLOCKS;
122 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
123 VEC_safe_grow_cleared (basic_block, gc, basic_block_info,
124 initial_cfg_capacity);
126 /* Build a mapping of labels to their associated blocks. */
127 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
128 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
129 initial_cfg_capacity);
131 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
132 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
133 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
134 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
137 /*---------------------------------------------------------------------------
139 ---------------------------------------------------------------------------*/
141 /* Entry point to the CFG builder for trees. TP points to the list of
142 statements to be added to the flowgraph. */
145 build_tree_cfg (tree *tp)
147 /* Register specific tree functions. */
148 tree_register_cfg_hooks ();
150 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
152 init_empty_tree_cfg ();
154 found_computed_goto = 0;
157 /* Computed gotos are hell to deal with, especially if there are
158 lots of them with a large number of destinations. So we factor
159 them to a common computed goto location before we build the
160 edge list. After we convert back to normal form, we will un-factor
161 the computed gotos since factoring introduces an unwanted jump. */
162 if (found_computed_goto)
163 factor_computed_gotos ();
165 /* Make sure there is always at least one block, even if it's empty. */
166 if (n_basic_blocks == NUM_FIXED_BLOCKS)
167 create_empty_bb (ENTRY_BLOCK_PTR);
169 /* Adjust the size of the array. */
170 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
171 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, n_basic_blocks);
173 /* To speed up statement iterator walks, we first purge dead labels. */
174 cleanup_dead_labels ();
176 /* Group case nodes to reduce the number of edges.
177 We do this after cleaning up dead labels because otherwise we miss
178 a lot of obvious case merging opportunities. */
179 group_case_labels ();
181 /* Create the edges of the flowgraph. */
183 cleanup_dead_labels ();
185 /* Debugging dumps. */
187 /* Write the flowgraph to a VCG file. */
189 int local_dump_flags;
190 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
193 tree_cfg2vcg (vcg_file);
194 dump_end (TDI_vcg, vcg_file);
198 #ifdef ENABLE_CHECKING
202 /* Dump a textual representation of the flowgraph. */
204 dump_tree_cfg (dump_file, dump_flags);
208 execute_build_cfg (void)
210 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
214 struct tree_opt_pass pass_build_cfg =
218 execute_build_cfg, /* execute */
221 0, /* static_pass_number */
222 TV_TREE_CFG, /* tv_id */
223 PROP_gimple_leh, /* properties_required */
224 PROP_cfg, /* properties_provided */
225 0, /* properties_destroyed */
226 0, /* todo_flags_start */
227 TODO_verify_stmts | TODO_cleanup_cfg, /* todo_flags_finish */
231 /* Search the CFG for any computed gotos. If found, factor them to a
232 common computed goto site. Also record the location of that site so
233 that we can un-factor the gotos after we have converted back to
237 factor_computed_gotos (void)
240 tree factored_label_decl = NULL;
242 tree factored_computed_goto_label = NULL;
243 tree factored_computed_goto = NULL;
245 /* We know there are one or more computed gotos in this function.
246 Examine the last statement in each basic block to see if the block
247 ends with a computed goto. */
251 block_stmt_iterator bsi = bsi_last (bb);
256 last = bsi_stmt (bsi);
258 /* Ignore the computed goto we create when we factor the original
260 if (last == factored_computed_goto)
263 /* If the last statement is a computed goto, factor it. */
264 if (computed_goto_p (last))
268 /* The first time we find a computed goto we need to create
269 the factored goto block and the variable each original
270 computed goto will use for their goto destination. */
271 if (! factored_computed_goto)
273 basic_block new_bb = create_empty_bb (bb);
274 block_stmt_iterator new_bsi = bsi_start (new_bb);
276 /* Create the destination of the factored goto. Each original
277 computed goto will put its desired destination into this
278 variable and jump to the label we create immediately
280 var = create_tmp_var (ptr_type_node, "gotovar");
282 /* Build a label for the new block which will contain the
283 factored computed goto. */
284 factored_label_decl = create_artificial_label ();
285 factored_computed_goto_label
286 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
287 bsi_insert_after (&new_bsi, factored_computed_goto_label,
290 /* Build our new computed goto. */
291 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
292 bsi_insert_after (&new_bsi, factored_computed_goto,
296 /* Copy the original computed goto's destination into VAR. */
297 assignment = build_gimple_modify_stmt (var,
298 GOTO_DESTINATION (last));
299 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
301 /* And re-vector the computed goto to the new destination. */
302 GOTO_DESTINATION (last) = factored_label_decl;
308 /* Build a flowgraph for the statement_list STMT_LIST. */
311 make_blocks (tree stmt_list)
313 tree_stmt_iterator i = tsi_start (stmt_list);
315 bool start_new_block = true;
316 bool first_stmt_of_list = true;
317 basic_block bb = ENTRY_BLOCK_PTR;
319 while (!tsi_end_p (i))
326 /* If the statement starts a new basic block or if we have determined
327 in a previous pass that we need to create a new block for STMT, do
329 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
331 if (!first_stmt_of_list)
332 stmt_list = tsi_split_statement_list_before (&i);
333 bb = create_basic_block (stmt_list, NULL, bb);
334 start_new_block = false;
337 /* Now add STMT to BB and create the subgraphs for special statement
339 set_bb_for_stmt (stmt, bb);
341 if (computed_goto_p (stmt))
342 found_computed_goto = true;
344 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
346 if (stmt_ends_bb_p (stmt))
347 start_new_block = true;
350 first_stmt_of_list = false;
355 /* Create and return a new empty basic block after bb AFTER. */
358 create_bb (void *h, void *e, basic_block after)
364 /* Create and initialize a new basic block. Since alloc_block uses
365 ggc_alloc_cleared to allocate a basic block, we do not have to
366 clear the newly allocated basic block here. */
369 bb->index = last_basic_block;
371 bb->il.tree = GGC_CNEW (struct tree_bb_info);
372 set_bb_stmt_list (bb, h ? (tree) h : alloc_stmt_list ());
374 /* Add the new block to the linked list of blocks. */
375 link_block (bb, after);
377 /* Grow the basic block array if needed. */
378 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
380 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
381 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
384 /* Add the newly created block to the array. */
385 SET_BASIC_BLOCK (last_basic_block, bb);
394 /*---------------------------------------------------------------------------
396 ---------------------------------------------------------------------------*/
398 /* Fold COND_EXPR_COND of each COND_EXPR. */
401 fold_cond_expr_cond (void)
407 tree stmt = last_stmt (bb);
410 && TREE_CODE (stmt) == COND_EXPR)
415 fold_defer_overflow_warnings ();
416 cond = fold (COND_EXPR_COND (stmt));
417 zerop = integer_zerop (cond);
418 onep = integer_onep (cond);
419 fold_undefer_overflow_warnings (((zerop || onep)
420 && !TREE_NO_WARNING (stmt)),
422 WARN_STRICT_OVERFLOW_CONDITIONAL);
424 COND_EXPR_COND (stmt) = boolean_false_node;
426 COND_EXPR_COND (stmt) = boolean_true_node;
431 /* Join all the blocks in the flowgraph. */
437 struct omp_region *cur_region = NULL;
439 /* Create an edge from entry to the first block with executable
441 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
443 /* Traverse the basic block array placing edges. */
446 tree last = last_stmt (bb);
451 enum tree_code code = TREE_CODE (last);
455 make_goto_expr_edges (bb);
459 make_edge (bb, EXIT_BLOCK_PTR, 0);
463 make_cond_expr_edges (bb);
467 make_switch_expr_edges (bb);
471 make_eh_edges (last);
476 /* If this function receives a nonlocal goto, then we need to
477 make edges from this call site to all the nonlocal goto
479 if (tree_can_make_abnormal_goto (last))
480 make_abnormal_goto_edges (bb, true);
482 /* If this statement has reachable exception handlers, then
483 create abnormal edges to them. */
484 make_eh_edges (last);
486 /* Some calls are known not to return. */
487 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
493 case GIMPLE_MODIFY_STMT:
494 if (is_ctrl_altering_stmt (last))
496 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
497 the CALL_EXPR may have an abnormal edge. Search the RHS
498 for this case and create any required edges. */
499 if (tree_can_make_abnormal_goto (last))
500 make_abnormal_goto_edges (bb, true);
502 make_eh_edges (last);
514 cur_region = new_omp_region (bb, code, cur_region);
519 cur_region = new_omp_region (bb, code, cur_region);
524 /* In the case of an OMP_SECTION, the edge will go somewhere
525 other than the next block. This will be created later. */
526 cur_region->exit = bb;
527 fallthru = cur_region->type != OMP_SECTION;
528 cur_region = cur_region->outer;
532 cur_region->cont = bb;
533 switch (cur_region->type)
536 /* ??? Technically there should be a some sort of loopback
537 edge here, but it goes to a block that doesn't exist yet,
538 and without it, updating the ssa form would be a real
539 bear. Fortunately, we don't yet do ssa before expanding
544 /* Wire up the edges into and out of the nested sections. */
545 /* ??? Similarly wrt loopback. */
547 struct omp_region *i;
548 for (i = cur_region->inner; i ; i = i->next)
550 gcc_assert (i->type == OMP_SECTION);
551 make_edge (cur_region->entry, i->entry, 0);
552 make_edge (i->exit, bb, EDGE_FALLTHRU);
564 gcc_assert (!stmt_ends_bb_p (last));
572 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
578 /* Fold COND_EXPR_COND of each COND_EXPR. */
579 fold_cond_expr_cond ();
583 /* Create the edges for a COND_EXPR starting at block BB.
584 At this point, both clauses must contain only simple gotos. */
587 make_cond_expr_edges (basic_block bb)
589 tree entry = last_stmt (bb);
590 basic_block then_bb, else_bb;
591 tree then_label, else_label;
595 gcc_assert (TREE_CODE (entry) == COND_EXPR);
597 /* Entry basic blocks for each component. */
598 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
599 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
600 then_bb = label_to_block (then_label);
601 else_bb = label_to_block (else_label);
603 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
604 #ifdef USE_MAPPED_LOCATION
605 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
607 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
609 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
612 #ifdef USE_MAPPED_LOCATION
613 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
615 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
619 /* We do not need the gotos anymore. */
620 COND_EXPR_THEN (entry) = NULL_TREE;
621 COND_EXPR_ELSE (entry) = NULL_TREE;
625 /* Called for each element in the hash table (P) as we delete the
626 edge to cases hash table.
628 Clear all the TREE_CHAINs to prevent problems with copying of
629 SWITCH_EXPRs and structure sharing rules, then free the hash table
633 edge_to_cases_cleanup (void *key ATTRIBUTE_UNUSED, void **value,
634 void *data ATTRIBUTE_UNUSED)
638 for (t = (tree) *value; t; t = next)
640 next = TREE_CHAIN (t);
641 TREE_CHAIN (t) = NULL;
648 /* Start recording information mapping edges to case labels. */
651 start_recording_case_labels (void)
653 gcc_assert (edge_to_cases == NULL);
654 edge_to_cases = pointer_map_create ();
657 /* Return nonzero if we are recording information for case labels. */
660 recording_case_labels_p (void)
662 return (edge_to_cases != NULL);
665 /* Stop recording information mapping edges to case labels and
666 remove any information we have recorded. */
668 end_recording_case_labels (void)
670 pointer_map_traverse (edge_to_cases, edge_to_cases_cleanup, NULL);
671 pointer_map_destroy (edge_to_cases);
672 edge_to_cases = NULL;
675 /* If we are inside a {start,end}_recording_cases block, then return
676 a chain of CASE_LABEL_EXPRs from T which reference E.
678 Otherwise return NULL. */
681 get_cases_for_edge (edge e, tree t)
687 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
688 chains available. Return NULL so the caller can detect this case. */
689 if (!recording_case_labels_p ())
692 slot = pointer_map_contains (edge_to_cases, e);
696 /* If we did not find E in the hash table, then this must be the first
697 time we have been queried for information about E & T. Add all the
698 elements from T to the hash table then perform the query again. */
700 vec = SWITCH_LABELS (t);
701 n = TREE_VEC_LENGTH (vec);
702 for (i = 0; i < n; i++)
704 tree elt = TREE_VEC_ELT (vec, i);
705 tree lab = CASE_LABEL (elt);
706 basic_block label_bb = label_to_block (lab);
707 edge this_edge = find_edge (e->src, label_bb);
709 /* Add it to the chain of CASE_LABEL_EXPRs referencing E, or create
711 slot = pointer_map_insert (edge_to_cases, this_edge);
712 TREE_CHAIN (elt) = (tree) *slot;
716 return (tree) *pointer_map_contains (edge_to_cases, e);
719 /* Create the edges for a SWITCH_EXPR starting at block BB.
720 At this point, the switch body has been lowered and the
721 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
724 make_switch_expr_edges (basic_block bb)
726 tree entry = last_stmt (bb);
730 vec = SWITCH_LABELS (entry);
731 n = TREE_VEC_LENGTH (vec);
733 for (i = 0; i < n; ++i)
735 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
736 basic_block label_bb = label_to_block (lab);
737 make_edge (bb, label_bb, 0);
742 /* Return the basic block holding label DEST. */
745 label_to_block_fn (struct function *ifun, tree dest)
747 int uid = LABEL_DECL_UID (dest);
749 /* We would die hard when faced by an undefined label. Emit a label to
750 the very first basic block. This will hopefully make even the dataflow
751 and undefined variable warnings quite right. */
752 if ((errorcount || sorrycount) && uid < 0)
754 block_stmt_iterator bsi =
755 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
758 stmt = build1 (LABEL_EXPR, void_type_node, dest);
759 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
760 uid = LABEL_DECL_UID (dest);
762 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
763 <= (unsigned int) uid)
765 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
768 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
769 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
772 make_abnormal_goto_edges (basic_block bb, bool for_call)
774 basic_block target_bb;
775 block_stmt_iterator bsi;
777 FOR_EACH_BB (target_bb)
778 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
780 tree target = bsi_stmt (bsi);
782 if (TREE_CODE (target) != LABEL_EXPR)
785 target = LABEL_EXPR_LABEL (target);
787 /* Make an edge to every label block that has been marked as a
788 potential target for a computed goto or a non-local goto. */
789 if ((FORCED_LABEL (target) && !for_call)
790 || (DECL_NONLOCAL (target) && for_call))
792 make_edge (bb, target_bb, EDGE_ABNORMAL);
798 /* Create edges for a goto statement at block BB. */
801 make_goto_expr_edges (basic_block bb)
803 block_stmt_iterator last = bsi_last (bb);
804 tree goto_t = bsi_stmt (last);
806 /* A simple GOTO creates normal edges. */
807 if (simple_goto_p (goto_t))
809 tree dest = GOTO_DESTINATION (goto_t);
810 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
811 #ifdef USE_MAPPED_LOCATION
812 e->goto_locus = EXPR_LOCATION (goto_t);
814 e->goto_locus = EXPR_LOCUS (goto_t);
816 bsi_remove (&last, true);
820 /* A computed GOTO creates abnormal edges. */
821 make_abnormal_goto_edges (bb, false);
825 /*---------------------------------------------------------------------------
827 ---------------------------------------------------------------------------*/
829 /* Cleanup useless labels in basic blocks. This is something we wish
830 to do early because it allows us to group case labels before creating
831 the edges for the CFG, and it speeds up block statement iterators in
833 We rerun this pass after CFG is created, to get rid of the labels that
834 are no longer referenced. After then we do not run it any more, since
835 (almost) no new labels should be created. */
837 /* A map from basic block index to the leading label of that block. */
838 static struct label_record
843 /* True if the label is referenced from somewhere. */
847 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
849 update_eh_label (struct eh_region *region)
851 tree old_label = get_eh_region_tree_label (region);
855 basic_block bb = label_to_block (old_label);
857 /* ??? After optimizing, there may be EH regions with labels
858 that have already been removed from the function body, so
859 there is no basic block for them. */
863 new_label = label_for_bb[bb->index].label;
864 label_for_bb[bb->index].used = true;
865 set_eh_region_tree_label (region, new_label);
869 /* Given LABEL return the first label in the same basic block. */
871 main_block_label (tree label)
873 basic_block bb = label_to_block (label);
874 tree main_label = label_for_bb[bb->index].label;
876 /* label_to_block possibly inserted undefined label into the chain. */
879 label_for_bb[bb->index].label = label;
883 label_for_bb[bb->index].used = true;
887 /* Cleanup redundant labels. This is a three-step process:
888 1) Find the leading label for each block.
889 2) Redirect all references to labels to the leading labels.
890 3) Cleanup all useless labels. */
893 cleanup_dead_labels (void)
896 label_for_bb = XCNEWVEC (struct label_record, last_basic_block);
898 /* Find a suitable label for each block. We use the first user-defined
899 label if there is one, or otherwise just the first label we see. */
902 block_stmt_iterator i;
904 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
906 tree label, stmt = bsi_stmt (i);
908 if (TREE_CODE (stmt) != LABEL_EXPR)
911 label = LABEL_EXPR_LABEL (stmt);
913 /* If we have not yet seen a label for the current block,
914 remember this one and see if there are more labels. */
915 if (!label_for_bb[bb->index].label)
917 label_for_bb[bb->index].label = label;
921 /* If we did see a label for the current block already, but it
922 is an artificially created label, replace it if the current
923 label is a user defined label. */
924 if (!DECL_ARTIFICIAL (label)
925 && DECL_ARTIFICIAL (label_for_bb[bb->index].label))
927 label_for_bb[bb->index].label = label;
933 /* Now redirect all jumps/branches to the selected label.
934 First do so for each block ending in a control statement. */
937 tree stmt = last_stmt (bb);
941 switch (TREE_CODE (stmt))
945 tree true_branch, false_branch;
947 true_branch = COND_EXPR_THEN (stmt);
948 false_branch = COND_EXPR_ELSE (stmt);
951 GOTO_DESTINATION (true_branch)
952 = main_block_label (GOTO_DESTINATION (true_branch));
954 GOTO_DESTINATION (false_branch)
955 = main_block_label (GOTO_DESTINATION (false_branch));
963 tree vec = SWITCH_LABELS (stmt);
964 size_t n = TREE_VEC_LENGTH (vec);
966 /* Replace all destination labels. */
967 for (i = 0; i < n; ++i)
969 tree elt = TREE_VEC_ELT (vec, i);
970 tree label = main_block_label (CASE_LABEL (elt));
971 CASE_LABEL (elt) = label;
976 /* We have to handle GOTO_EXPRs until they're removed, and we don't
977 remove them until after we've created the CFG edges. */
979 if (! computed_goto_p (stmt))
981 GOTO_DESTINATION (stmt)
982 = main_block_label (GOTO_DESTINATION (stmt));
991 for_each_eh_region (update_eh_label);
993 /* Finally, purge dead labels. All user-defined labels and labels that
994 can be the target of non-local gotos and labels which have their
995 address taken are preserved. */
998 block_stmt_iterator i;
999 tree label_for_this_bb = label_for_bb[bb->index].label;
1001 if (!label_for_this_bb)
1004 /* If the main label of the block is unused, we may still remove it. */
1005 if (!label_for_bb[bb->index].used)
1006 label_for_this_bb = NULL;
1008 for (i = bsi_start (bb); !bsi_end_p (i); )
1010 tree label, stmt = bsi_stmt (i);
1012 if (TREE_CODE (stmt) != LABEL_EXPR)
1015 label = LABEL_EXPR_LABEL (stmt);
1017 if (label == label_for_this_bb
1018 || ! DECL_ARTIFICIAL (label)
1019 || DECL_NONLOCAL (label)
1020 || FORCED_LABEL (label))
1023 bsi_remove (&i, true);
1027 free (label_for_bb);
1030 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1031 and scan the sorted vector of cases. Combine the ones jumping to the
1033 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1036 group_case_labels (void)
1042 tree stmt = last_stmt (bb);
1043 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1045 tree labels = SWITCH_LABELS (stmt);
1046 int old_size = TREE_VEC_LENGTH (labels);
1047 int i, j, new_size = old_size;
1048 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1051 /* The default label is always the last case in a switch
1052 statement after gimplification. */
1053 default_label = CASE_LABEL (default_case);
1055 /* Look for possible opportunities to merge cases.
1056 Ignore the last element of the label vector because it
1057 must be the default case. */
1059 while (i < old_size - 1)
1061 tree base_case, base_label, base_high;
1062 base_case = TREE_VEC_ELT (labels, i);
1064 gcc_assert (base_case);
1065 base_label = CASE_LABEL (base_case);
1067 /* Discard cases that have the same destination as the
1069 if (base_label == default_label)
1071 TREE_VEC_ELT (labels, i) = NULL_TREE;
1077 base_high = CASE_HIGH (base_case) ?
1078 CASE_HIGH (base_case) : CASE_LOW (base_case);
1080 /* Try to merge case labels. Break out when we reach the end
1081 of the label vector or when we cannot merge the next case
1082 label with the current one. */
1083 while (i < old_size - 1)
1085 tree merge_case = TREE_VEC_ELT (labels, i);
1086 tree merge_label = CASE_LABEL (merge_case);
1087 tree t = int_const_binop (PLUS_EXPR, base_high,
1088 integer_one_node, 1);
1090 /* Merge the cases if they jump to the same place,
1091 and their ranges are consecutive. */
1092 if (merge_label == base_label
1093 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1095 base_high = CASE_HIGH (merge_case) ?
1096 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1097 CASE_HIGH (base_case) = base_high;
1098 TREE_VEC_ELT (labels, i) = NULL_TREE;
1107 /* Compress the case labels in the label vector, and adjust the
1108 length of the vector. */
1109 for (i = 0, j = 0; i < new_size; i++)
1111 while (! TREE_VEC_ELT (labels, j))
1113 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1115 TREE_VEC_LENGTH (labels) = new_size;
1120 /* Checks whether we can merge block B into block A. */
1123 tree_can_merge_blocks_p (basic_block a, basic_block b)
1126 block_stmt_iterator bsi;
1129 if (!single_succ_p (a))
1132 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1135 if (single_succ (a) != b)
1138 if (!single_pred_p (b))
1141 if (b == EXIT_BLOCK_PTR)
1144 /* If A ends by a statement causing exceptions or something similar, we
1145 cannot merge the blocks. */
1146 stmt = last_stmt (a);
1147 if (stmt && stmt_ends_bb_p (stmt))
1150 /* Do not allow a block with only a non-local label to be merged. */
1151 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1152 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1155 /* It must be possible to eliminate all phi nodes in B. If ssa form
1156 is not up-to-date, we cannot eliminate any phis; however, if only
1157 some symbols as whole are marked for renaming, this is not a problem,
1158 as phi nodes for those symbols are irrelevant in updating anyway. */
1159 phi = phi_nodes (b);
1162 if (name_mappings_registered_p ())
1165 for (; phi; phi = PHI_CHAIN (phi))
1166 if (!is_gimple_reg (PHI_RESULT (phi))
1167 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1171 /* Do not remove user labels. */
1172 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1174 stmt = bsi_stmt (bsi);
1175 if (TREE_CODE (stmt) != LABEL_EXPR)
1177 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1181 /* Protect the loop latches. */
1183 && b->loop_father->latch == b)
1189 /* Replaces all uses of NAME by VAL. */
1192 replace_uses_by (tree name, tree val)
1194 imm_use_iterator imm_iter;
1199 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1201 if (TREE_CODE (stmt) != PHI_NODE)
1202 push_stmt_changes (&stmt);
1204 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1206 replace_exp (use, val);
1208 if (TREE_CODE (stmt) == PHI_NODE)
1210 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1211 if (e->flags & EDGE_ABNORMAL)
1213 /* This can only occur for virtual operands, since
1214 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1215 would prevent replacement. */
1216 gcc_assert (!is_gimple_reg (name));
1217 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1222 if (TREE_CODE (stmt) != PHI_NODE)
1226 fold_stmt_inplace (stmt);
1227 if (cfgcleanup_altered_bbs)
1228 bitmap_set_bit (cfgcleanup_altered_bbs, bb_for_stmt (stmt)->index);
1230 /* FIXME. This should go in pop_stmt_changes. */
1231 rhs = get_rhs (stmt);
1232 if (TREE_CODE (rhs) == ADDR_EXPR)
1233 recompute_tree_invariant_for_addr_expr (rhs);
1235 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1237 pop_stmt_changes (&stmt);
1241 gcc_assert (has_zero_uses (name));
1243 /* Also update the trees stored in loop structures. */
1249 FOR_EACH_LOOP (li, loop, 0)
1251 substitute_in_loop_info (loop, name, val);
1256 /* Merge block B into block A. */
1259 tree_merge_blocks (basic_block a, basic_block b)
1261 block_stmt_iterator bsi;
1262 tree_stmt_iterator last;
1266 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1268 /* Remove all single-valued PHI nodes from block B of the form
1269 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1271 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1273 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1275 bool may_replace_uses = may_propagate_copy (def, use);
1277 /* In case we have loops to care about, do not propagate arguments of
1278 loop closed ssa phi nodes. */
1280 && is_gimple_reg (def)
1281 && TREE_CODE (use) == SSA_NAME
1282 && a->loop_father != b->loop_father)
1283 may_replace_uses = false;
1285 if (!may_replace_uses)
1287 gcc_assert (is_gimple_reg (def));
1289 /* Note that just emitting the copies is fine -- there is no problem
1290 with ordering of phi nodes. This is because A is the single
1291 predecessor of B, therefore results of the phi nodes cannot
1292 appear as arguments of the phi nodes. */
1293 copy = build_gimple_modify_stmt (def, use);
1294 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1295 SSA_NAME_DEF_STMT (def) = copy;
1296 remove_phi_node (phi, NULL, false);
1300 replace_uses_by (def, use);
1301 remove_phi_node (phi, NULL, true);
1305 /* Ensure that B follows A. */
1306 move_block_after (b, a);
1308 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1309 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1311 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1312 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1314 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1316 tree label = bsi_stmt (bsi);
1318 bsi_remove (&bsi, false);
1319 /* Now that we can thread computed gotos, we might have
1320 a situation where we have a forced label in block B
1321 However, the label at the start of block B might still be
1322 used in other ways (think about the runtime checking for
1323 Fortran assigned gotos). So we can not just delete the
1324 label. Instead we move the label to the start of block A. */
1325 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1327 block_stmt_iterator dest_bsi = bsi_start (a);
1328 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1333 change_bb_for_stmt (bsi_stmt (bsi), a);
1338 /* Merge the chains. */
1339 last = tsi_last (bb_stmt_list (a));
1340 tsi_link_after (&last, bb_stmt_list (b), TSI_NEW_STMT);
1341 set_bb_stmt_list (b, NULL_TREE);
1343 if (cfgcleanup_altered_bbs)
1344 bitmap_set_bit (cfgcleanup_altered_bbs, a->index);
1348 /* Return the one of two successors of BB that is not reachable by a
1349 reached by a complex edge, if there is one. Else, return BB. We use
1350 this in optimizations that use post-dominators for their heuristics,
1351 to catch the cases in C++ where function calls are involved. */
1354 single_noncomplex_succ (basic_block bb)
1357 if (EDGE_COUNT (bb->succs) != 2)
1360 e0 = EDGE_SUCC (bb, 0);
1361 e1 = EDGE_SUCC (bb, 1);
1362 if (e0->flags & EDGE_COMPLEX)
1364 if (e1->flags & EDGE_COMPLEX)
1371 /* Walk the function tree removing unnecessary statements.
1373 * Empty statement nodes are removed
1375 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1377 * Unnecessary COND_EXPRs are removed
1379 * Some unnecessary BIND_EXPRs are removed
1381 Clearly more work could be done. The trick is doing the analysis
1382 and removal fast enough to be a net improvement in compile times.
1384 Note that when we remove a control structure such as a COND_EXPR
1385 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1386 to ensure we eliminate all the useless code. */
1397 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1400 remove_useless_stmts_warn_notreached (tree stmt)
1402 if (EXPR_HAS_LOCATION (stmt))
1404 location_t loc = EXPR_LOCATION (stmt);
1405 if (LOCATION_LINE (loc) > 0)
1407 warning (0, "%Hwill never be executed", &loc);
1412 switch (TREE_CODE (stmt))
1414 case STATEMENT_LIST:
1416 tree_stmt_iterator i;
1417 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1418 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1424 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1426 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1428 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1432 case TRY_FINALLY_EXPR:
1433 case TRY_CATCH_EXPR:
1434 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1436 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1441 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1442 case EH_FILTER_EXPR:
1443 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1445 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1448 /* Not a live container. */
1456 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1458 tree then_clause, else_clause, cond;
1459 bool save_has_label, then_has_label, else_has_label;
1461 save_has_label = data->has_label;
1462 data->has_label = false;
1463 data->last_goto = NULL;
1465 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1467 then_has_label = data->has_label;
1468 data->has_label = false;
1469 data->last_goto = NULL;
1471 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1473 else_has_label = data->has_label;
1474 data->has_label = save_has_label | then_has_label | else_has_label;
1476 then_clause = COND_EXPR_THEN (*stmt_p);
1477 else_clause = COND_EXPR_ELSE (*stmt_p);
1478 cond = fold (COND_EXPR_COND (*stmt_p));
1480 /* If neither arm does anything at all, we can remove the whole IF. */
1481 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1483 *stmt_p = build_empty_stmt ();
1484 data->repeat = true;
1487 /* If there are no reachable statements in an arm, then we can
1488 zap the entire conditional. */
1489 else if (integer_nonzerop (cond) && !else_has_label)
1491 if (warn_notreached)
1492 remove_useless_stmts_warn_notreached (else_clause);
1493 *stmt_p = then_clause;
1494 data->repeat = true;
1496 else if (integer_zerop (cond) && !then_has_label)
1498 if (warn_notreached)
1499 remove_useless_stmts_warn_notreached (then_clause);
1500 *stmt_p = else_clause;
1501 data->repeat = true;
1504 /* Check a couple of simple things on then/else with single stmts. */
1507 tree then_stmt = expr_only (then_clause);
1508 tree else_stmt = expr_only (else_clause);
1510 /* Notice branches to a common destination. */
1511 if (then_stmt && else_stmt
1512 && TREE_CODE (then_stmt) == GOTO_EXPR
1513 && TREE_CODE (else_stmt) == GOTO_EXPR
1514 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1516 *stmt_p = then_stmt;
1517 data->repeat = true;
1520 /* If the THEN/ELSE clause merely assigns a value to a variable or
1521 parameter which is already known to contain that value, then
1522 remove the useless THEN/ELSE clause. */
1523 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1526 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1527 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1528 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1529 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1531 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1532 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1533 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1534 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1536 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1537 ? then_stmt : else_stmt);
1538 tree *location = (TREE_CODE (cond) == EQ_EXPR
1539 ? &COND_EXPR_THEN (*stmt_p)
1540 : &COND_EXPR_ELSE (*stmt_p));
1543 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1544 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1545 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1546 *location = alloc_stmt_list ();
1550 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1551 would be re-introduced during lowering. */
1552 data->last_goto = NULL;
1557 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1559 bool save_may_branch, save_may_throw;
1560 bool this_may_branch, this_may_throw;
1562 /* Collect may_branch and may_throw information for the body only. */
1563 save_may_branch = data->may_branch;
1564 save_may_throw = data->may_throw;
1565 data->may_branch = false;
1566 data->may_throw = false;
1567 data->last_goto = NULL;
1569 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1571 this_may_branch = data->may_branch;
1572 this_may_throw = data->may_throw;
1573 data->may_branch |= save_may_branch;
1574 data->may_throw |= save_may_throw;
1575 data->last_goto = NULL;
1577 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1579 /* If the body is empty, then we can emit the FINALLY block without
1580 the enclosing TRY_FINALLY_EXPR. */
1581 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1583 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1584 data->repeat = true;
1587 /* If the handler is empty, then we can emit the TRY block without
1588 the enclosing TRY_FINALLY_EXPR. */
1589 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1591 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1592 data->repeat = true;
1595 /* If the body neither throws, nor branches, then we can safely
1596 string the TRY and FINALLY blocks together. */
1597 else if (!this_may_branch && !this_may_throw)
1599 tree stmt = *stmt_p;
1600 *stmt_p = TREE_OPERAND (stmt, 0);
1601 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1602 data->repeat = true;
1608 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1610 bool save_may_throw, this_may_throw;
1611 tree_stmt_iterator i;
1614 /* Collect may_throw information for the body only. */
1615 save_may_throw = data->may_throw;
1616 data->may_throw = false;
1617 data->last_goto = NULL;
1619 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1621 this_may_throw = data->may_throw;
1622 data->may_throw = save_may_throw;
1624 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1625 if (!this_may_throw)
1627 if (warn_notreached)
1628 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1629 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1630 data->repeat = true;
1634 /* Process the catch clause specially. We may be able to tell that
1635 no exceptions propagate past this point. */
1637 this_may_throw = true;
1638 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1639 stmt = tsi_stmt (i);
1640 data->last_goto = NULL;
1642 switch (TREE_CODE (stmt))
1645 for (; !tsi_end_p (i); tsi_next (&i))
1647 stmt = tsi_stmt (i);
1648 /* If we catch all exceptions, then the body does not
1649 propagate exceptions past this point. */
1650 if (CATCH_TYPES (stmt) == NULL)
1651 this_may_throw = false;
1652 data->last_goto = NULL;
1653 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1657 case EH_FILTER_EXPR:
1658 if (EH_FILTER_MUST_NOT_THROW (stmt))
1659 this_may_throw = false;
1660 else if (EH_FILTER_TYPES (stmt) == NULL)
1661 this_may_throw = false;
1662 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1666 /* Otherwise this is a cleanup. */
1667 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1669 /* If the cleanup is empty, then we can emit the TRY block without
1670 the enclosing TRY_CATCH_EXPR. */
1671 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1673 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1674 data->repeat = true;
1678 data->may_throw |= this_may_throw;
1683 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1687 /* First remove anything underneath the BIND_EXPR. */
1688 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1690 /* If the BIND_EXPR has no variables, then we can pull everything
1691 up one level and remove the BIND_EXPR, unless this is the toplevel
1692 BIND_EXPR for the current function or an inlined function.
1694 When this situation occurs we will want to apply this
1695 optimization again. */
1696 block = BIND_EXPR_BLOCK (*stmt_p);
1697 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1698 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1700 || ! BLOCK_ABSTRACT_ORIGIN (block)
1701 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1704 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1705 data->repeat = true;
1711 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1713 tree dest = GOTO_DESTINATION (*stmt_p);
1715 data->may_branch = true;
1716 data->last_goto = NULL;
1718 /* Record the last goto expr, so that we can delete it if unnecessary. */
1719 if (TREE_CODE (dest) == LABEL_DECL)
1720 data->last_goto = stmt_p;
1725 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1727 tree label = LABEL_EXPR_LABEL (*stmt_p);
1729 data->has_label = true;
1731 /* We do want to jump across non-local label receiver code. */
1732 if (DECL_NONLOCAL (label))
1733 data->last_goto = NULL;
1735 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1737 *data->last_goto = build_empty_stmt ();
1738 data->repeat = true;
1741 /* ??? Add something here to delete unused labels. */
1745 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1746 decl. This allows us to eliminate redundant or useless
1747 calls to "const" functions.
1749 Gimplifier already does the same operation, but we may notice functions
1750 being const and pure once their calls has been gimplified, so we need
1751 to update the flag. */
1754 update_call_expr_flags (tree call)
1756 tree decl = get_callee_fndecl (call);
1759 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1760 TREE_SIDE_EFFECTS (call) = 0;
1761 if (TREE_NOTHROW (decl))
1762 TREE_NOTHROW (call) = 1;
1766 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1769 notice_special_calls (tree t)
1771 int flags = call_expr_flags (t);
1773 if (flags & ECF_MAY_BE_ALLOCA)
1774 current_function_calls_alloca = true;
1775 if (flags & ECF_RETURNS_TWICE)
1776 current_function_calls_setjmp = true;
1780 /* Clear flags set by notice_special_calls. Used by dead code removal
1781 to update the flags. */
1784 clear_special_calls (void)
1786 current_function_calls_alloca = false;
1787 current_function_calls_setjmp = false;
1792 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1796 switch (TREE_CODE (t))
1799 remove_useless_stmts_cond (tp, data);
1802 case TRY_FINALLY_EXPR:
1803 remove_useless_stmts_tf (tp, data);
1806 case TRY_CATCH_EXPR:
1807 remove_useless_stmts_tc (tp, data);
1811 remove_useless_stmts_bind (tp, data);
1815 remove_useless_stmts_goto (tp, data);
1819 remove_useless_stmts_label (tp, data);
1824 data->last_goto = NULL;
1825 data->may_branch = true;
1830 data->last_goto = NULL;
1831 notice_special_calls (t);
1832 update_call_expr_flags (t);
1833 if (tree_could_throw_p (t))
1834 data->may_throw = true;
1840 case GIMPLE_MODIFY_STMT:
1841 data->last_goto = NULL;
1843 op = get_call_expr_in (t);
1846 update_call_expr_flags (op);
1847 notice_special_calls (op);
1849 if (tree_could_throw_p (t))
1850 data->may_throw = true;
1853 case STATEMENT_LIST:
1855 tree_stmt_iterator i = tsi_start (t);
1856 while (!tsi_end_p (i))
1859 if (IS_EMPTY_STMT (t))
1865 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1868 if (TREE_CODE (t) == STATEMENT_LIST)
1870 tsi_link_before (&i, t, TSI_SAME_STMT);
1880 data->last_goto = NULL;
1884 data->last_goto = NULL;
1890 remove_useless_stmts (void)
1892 struct rus_data data;
1894 clear_special_calls ();
1898 memset (&data, 0, sizeof (data));
1899 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1901 while (data.repeat);
1906 struct tree_opt_pass pass_remove_useless_stmts =
1908 "useless", /* name */
1910 remove_useless_stmts, /* execute */
1913 0, /* static_pass_number */
1915 PROP_gimple_any, /* properties_required */
1916 0, /* properties_provided */
1917 0, /* properties_destroyed */
1918 0, /* todo_flags_start */
1919 TODO_dump_func, /* todo_flags_finish */
1923 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1926 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1930 /* Since this block is no longer reachable, we can just delete all
1931 of its PHI nodes. */
1932 phi = phi_nodes (bb);
1935 tree next = PHI_CHAIN (phi);
1936 remove_phi_node (phi, NULL_TREE, true);
1940 /* Remove edges to BB's successors. */
1941 while (EDGE_COUNT (bb->succs) > 0)
1942 remove_edge (EDGE_SUCC (bb, 0));
1946 /* Remove statements of basic block BB. */
1949 remove_bb (basic_block bb)
1951 block_stmt_iterator i;
1952 #ifdef USE_MAPPED_LOCATION
1953 source_location loc = UNKNOWN_LOCATION;
1955 source_locus loc = 0;
1960 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1961 if (dump_flags & TDF_DETAILS)
1963 dump_bb (bb, dump_file, 0);
1964 fprintf (dump_file, "\n");
1970 struct loop *loop = bb->loop_father;
1972 /* If a loop gets removed, clean up the information associated
1974 if (loop->latch == bb
1975 || loop->header == bb)
1976 free_numbers_of_iterations_estimates_loop (loop);
1979 /* Remove all the instructions in the block. */
1980 if (bb_stmt_list (bb) != NULL_TREE)
1982 for (i = bsi_start (bb); !bsi_end_p (i);)
1984 tree stmt = bsi_stmt (i);
1985 if (TREE_CODE (stmt) == LABEL_EXPR
1986 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
1987 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
1990 block_stmt_iterator new_bsi;
1992 /* A non-reachable non-local label may still be referenced.
1993 But it no longer needs to carry the extra semantics of
1995 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1997 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
1998 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2001 new_bb = bb->prev_bb;
2002 new_bsi = bsi_start (new_bb);
2003 bsi_remove (&i, false);
2004 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2008 /* Release SSA definitions if we are in SSA. Note that we
2009 may be called when not in SSA. For example,
2010 final_cleanup calls this function via
2011 cleanup_tree_cfg. */
2012 if (gimple_in_ssa_p (cfun))
2013 release_defs (stmt);
2015 bsi_remove (&i, true);
2018 /* Don't warn for removed gotos. Gotos are often removed due to
2019 jump threading, thus resulting in bogus warnings. Not great,
2020 since this way we lose warnings for gotos in the original
2021 program that are indeed unreachable. */
2022 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2024 #ifdef USE_MAPPED_LOCATION
2025 if (EXPR_HAS_LOCATION (stmt))
2026 loc = EXPR_LOCATION (stmt);
2029 t = EXPR_LOCUS (stmt);
2030 if (t && LOCATION_LINE (*t) > 0)
2037 /* If requested, give a warning that the first statement in the
2038 block is unreachable. We walk statements backwards in the
2039 loop above, so the last statement we process is the first statement
2041 #ifdef USE_MAPPED_LOCATION
2042 if (loc > BUILTINS_LOCATION)
2043 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2046 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2049 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2054 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2055 predicate VAL, return the edge that will be taken out of the block.
2056 If VAL does not match a unique edge, NULL is returned. */
2059 find_taken_edge (basic_block bb, tree val)
2063 stmt = last_stmt (bb);
2066 gcc_assert (is_ctrl_stmt (stmt));
2069 if (! is_gimple_min_invariant (val))
2072 if (TREE_CODE (stmt) == COND_EXPR)
2073 return find_taken_edge_cond_expr (bb, val);
2075 if (TREE_CODE (stmt) == SWITCH_EXPR)
2076 return find_taken_edge_switch_expr (bb, val);
2078 if (computed_goto_p (stmt))
2080 /* Only optimize if the argument is a label, if the argument is
2081 not a label then we can not construct a proper CFG.
2083 It may be the case that we only need to allow the LABEL_REF to
2084 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2085 appear inside a LABEL_EXPR just to be safe. */
2086 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2087 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2088 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2095 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2096 statement, determine which of the outgoing edges will be taken out of the
2097 block. Return NULL if either edge may be taken. */
2100 find_taken_edge_computed_goto (basic_block bb, tree val)
2105 dest = label_to_block (val);
2108 e = find_edge (bb, dest);
2109 gcc_assert (e != NULL);
2115 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2116 statement, determine which of the two edges will be taken out of the
2117 block. Return NULL if either edge may be taken. */
2120 find_taken_edge_cond_expr (basic_block bb, tree val)
2122 edge true_edge, false_edge;
2124 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2126 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2127 return (integer_zerop (val) ? false_edge : true_edge);
2130 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2131 statement, determine which edge will be taken out of the block. Return
2132 NULL if any edge may be taken. */
2135 find_taken_edge_switch_expr (basic_block bb, tree val)
2137 tree switch_expr, taken_case;
2138 basic_block dest_bb;
2141 switch_expr = last_stmt (bb);
2142 taken_case = find_case_label_for_value (switch_expr, val);
2143 dest_bb = label_to_block (CASE_LABEL (taken_case));
2145 e = find_edge (bb, dest_bb);
2151 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2152 We can make optimal use here of the fact that the case labels are
2153 sorted: We can do a binary search for a case matching VAL. */
2156 find_case_label_for_value (tree switch_expr, tree val)
2158 tree vec = SWITCH_LABELS (switch_expr);
2159 size_t low, high, n = TREE_VEC_LENGTH (vec);
2160 tree default_case = TREE_VEC_ELT (vec, n - 1);
2162 for (low = -1, high = n - 1; high - low > 1; )
2164 size_t i = (high + low) / 2;
2165 tree t = TREE_VEC_ELT (vec, i);
2168 /* Cache the result of comparing CASE_LOW and val. */
2169 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2176 if (CASE_HIGH (t) == NULL)
2178 /* A singe-valued case label. */
2184 /* A case range. We can only handle integer ranges. */
2185 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2190 return default_case;
2196 /*---------------------------------------------------------------------------
2198 ---------------------------------------------------------------------------*/
2200 /* Dump tree-specific information of block BB to file OUTF. */
2203 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2205 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2209 /* Dump a basic block on stderr. */
2212 debug_tree_bb (basic_block bb)
2214 dump_bb (bb, stderr, 0);
2218 /* Dump basic block with index N on stderr. */
2221 debug_tree_bb_n (int n)
2223 debug_tree_bb (BASIC_BLOCK (n));
2224 return BASIC_BLOCK (n);
2228 /* Dump the CFG on stderr.
2230 FLAGS are the same used by the tree dumping functions
2231 (see TDF_* in tree-pass.h). */
2234 debug_tree_cfg (int flags)
2236 dump_tree_cfg (stderr, flags);
2240 /* Dump the program showing basic block boundaries on the given FILE.
2242 FLAGS are the same used by the tree dumping functions (see TDF_* in
2246 dump_tree_cfg (FILE *file, int flags)
2248 if (flags & TDF_DETAILS)
2250 const char *funcname
2251 = lang_hooks.decl_printable_name (current_function_decl, 2);
2254 fprintf (file, ";; Function %s\n\n", funcname);
2255 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2256 n_basic_blocks, n_edges, last_basic_block);
2258 brief_dump_cfg (file);
2259 fprintf (file, "\n");
2262 if (flags & TDF_STATS)
2263 dump_cfg_stats (file);
2265 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2269 /* Dump CFG statistics on FILE. */
2272 dump_cfg_stats (FILE *file)
2274 static long max_num_merged_labels = 0;
2275 unsigned long size, total = 0;
2278 const char * const fmt_str = "%-30s%-13s%12s\n";
2279 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2280 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2281 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2282 const char *funcname
2283 = lang_hooks.decl_printable_name (current_function_decl, 2);
2286 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2288 fprintf (file, "---------------------------------------------------------\n");
2289 fprintf (file, fmt_str, "", " Number of ", "Memory");
2290 fprintf (file, fmt_str, "", " instances ", "used ");
2291 fprintf (file, "---------------------------------------------------------\n");
2293 size = n_basic_blocks * sizeof (struct basic_block_def);
2295 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2296 SCALE (size), LABEL (size));
2300 num_edges += EDGE_COUNT (bb->succs);
2301 size = num_edges * sizeof (struct edge_def);
2303 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2305 fprintf (file, "---------------------------------------------------------\n");
2306 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2308 fprintf (file, "---------------------------------------------------------\n");
2309 fprintf (file, "\n");
2311 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2312 max_num_merged_labels = cfg_stats.num_merged_labels;
2314 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2315 cfg_stats.num_merged_labels, max_num_merged_labels);
2317 fprintf (file, "\n");
2321 /* Dump CFG statistics on stderr. Keep extern so that it's always
2322 linked in the final executable. */
2325 debug_cfg_stats (void)
2327 dump_cfg_stats (stderr);
2331 /* Dump the flowgraph to a .vcg FILE. */
2334 tree_cfg2vcg (FILE *file)
2339 const char *funcname
2340 = lang_hooks.decl_printable_name (current_function_decl, 2);
2342 /* Write the file header. */
2343 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2344 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2345 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2347 /* Write blocks and edges. */
2348 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2350 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2353 if (e->flags & EDGE_FAKE)
2354 fprintf (file, " linestyle: dotted priority: 10");
2356 fprintf (file, " linestyle: solid priority: 100");
2358 fprintf (file, " }\n");
2364 enum tree_code head_code, end_code;
2365 const char *head_name, *end_name;
2368 tree first = first_stmt (bb);
2369 tree last = last_stmt (bb);
2373 head_code = TREE_CODE (first);
2374 head_name = tree_code_name[head_code];
2375 head_line = get_lineno (first);
2378 head_name = "no-statement";
2382 end_code = TREE_CODE (last);
2383 end_name = tree_code_name[end_code];
2384 end_line = get_lineno (last);
2387 end_name = "no-statement";
2389 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2390 bb->index, bb->index, head_name, head_line, end_name,
2393 FOR_EACH_EDGE (e, ei, bb->succs)
2395 if (e->dest == EXIT_BLOCK_PTR)
2396 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2398 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2400 if (e->flags & EDGE_FAKE)
2401 fprintf (file, " priority: 10 linestyle: dotted");
2403 fprintf (file, " priority: 100 linestyle: solid");
2405 fprintf (file, " }\n");
2408 if (bb->next_bb != EXIT_BLOCK_PTR)
2412 fputs ("}\n\n", file);
2417 /*---------------------------------------------------------------------------
2418 Miscellaneous helpers
2419 ---------------------------------------------------------------------------*/
2421 /* Return true if T represents a stmt that always transfers control. */
2424 is_ctrl_stmt (tree t)
2426 return (TREE_CODE (t) == COND_EXPR
2427 || TREE_CODE (t) == SWITCH_EXPR
2428 || TREE_CODE (t) == GOTO_EXPR
2429 || TREE_CODE (t) == RETURN_EXPR
2430 || TREE_CODE (t) == RESX_EXPR);
2434 /* Return true if T is a statement that may alter the flow of control
2435 (e.g., a call to a non-returning function). */
2438 is_ctrl_altering_stmt (tree t)
2443 call = get_call_expr_in (t);
2446 /* A non-pure/const CALL_EXPR alters flow control if the current
2447 function has nonlocal labels. */
2448 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2451 /* A CALL_EXPR also alters control flow if it does not return. */
2452 if (call_expr_flags (call) & ECF_NORETURN)
2456 /* OpenMP directives alter control flow. */
2457 if (OMP_DIRECTIVE_P (t))
2460 /* If a statement can throw, it alters control flow. */
2461 return tree_can_throw_internal (t);
2465 /* Return true if T is a computed goto. */
2468 computed_goto_p (tree t)
2470 return (TREE_CODE (t) == GOTO_EXPR
2471 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2475 /* Return true if T is a simple local goto. */
2478 simple_goto_p (tree t)
2480 return (TREE_CODE (t) == GOTO_EXPR
2481 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2485 /* Return true if T can make an abnormal transfer of control flow.
2486 Transfers of control flow associated with EH are excluded. */
2489 tree_can_make_abnormal_goto (tree t)
2491 if (computed_goto_p (t))
2493 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2494 t = GIMPLE_STMT_OPERAND (t, 1);
2495 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2496 t = TREE_OPERAND (t, 0);
2497 if (TREE_CODE (t) == CALL_EXPR)
2498 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2503 /* Return true if T should start a new basic block. PREV_T is the
2504 statement preceding T. It is used when T is a label or a case label.
2505 Labels should only start a new basic block if their previous statement
2506 wasn't a label. Otherwise, sequence of labels would generate
2507 unnecessary basic blocks that only contain a single label. */
2510 stmt_starts_bb_p (tree t, tree prev_t)
2515 /* LABEL_EXPRs start a new basic block only if the preceding
2516 statement wasn't a label of the same type. This prevents the
2517 creation of consecutive blocks that have nothing but a single
2519 if (TREE_CODE (t) == LABEL_EXPR)
2521 /* Nonlocal and computed GOTO targets always start a new block. */
2522 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2523 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2526 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2528 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2531 cfg_stats.num_merged_labels++;
2542 /* Return true if T should end a basic block. */
2545 stmt_ends_bb_p (tree t)
2547 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2550 /* Remove block annotations and other datastructures. */
2553 delete_tree_cfg_annotations (void)
2556 block_stmt_iterator bsi;
2558 /* Remove annotations from every tree in the function. */
2560 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2562 tree stmt = bsi_stmt (bsi);
2563 ggc_free (stmt->base.ann);
2564 stmt->base.ann = NULL;
2566 label_to_block_map = NULL;
2570 /* Return the first statement in basic block BB. */
2573 first_stmt (basic_block bb)
2575 block_stmt_iterator i = bsi_start (bb);
2576 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2580 /* Return the last statement in basic block BB. */
2583 last_stmt (basic_block bb)
2585 block_stmt_iterator b = bsi_last (bb);
2586 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2590 /* Return the last statement of an otherwise empty block. Return NULL
2591 if the block is totally empty, or if it contains more than one
2595 last_and_only_stmt (basic_block bb)
2597 block_stmt_iterator i = bsi_last (bb);
2603 last = bsi_stmt (i);
2608 /* Empty statements should no longer appear in the instruction stream.
2609 Everything that might have appeared before should be deleted by
2610 remove_useless_stmts, and the optimizers should just bsi_remove
2611 instead of smashing with build_empty_stmt.
2613 Thus the only thing that should appear here in a block containing
2614 one executable statement is a label. */
2615 prev = bsi_stmt (i);
2616 if (TREE_CODE (prev) == LABEL_EXPR)
2623 /* Mark BB as the basic block holding statement T. */
2626 set_bb_for_stmt (tree t, basic_block bb)
2628 if (TREE_CODE (t) == PHI_NODE)
2630 else if (TREE_CODE (t) == STATEMENT_LIST)
2632 tree_stmt_iterator i;
2633 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2634 set_bb_for_stmt (tsi_stmt (i), bb);
2638 stmt_ann_t ann = get_stmt_ann (t);
2641 /* If the statement is a label, add the label to block-to-labels map
2642 so that we can speed up edge creation for GOTO_EXPRs. */
2643 if (TREE_CODE (t) == LABEL_EXPR)
2647 t = LABEL_EXPR_LABEL (t);
2648 uid = LABEL_DECL_UID (t);
2651 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2652 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2653 if (old_len <= (unsigned) uid)
2655 unsigned new_len = 3 * uid / 2;
2657 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2662 /* We're moving an existing label. Make sure that we've
2663 removed it from the old block. */
2665 || !VEC_index (basic_block, label_to_block_map, uid));
2666 VEC_replace (basic_block, label_to_block_map, uid, bb);
2671 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2672 from one basic block to another.
2673 For BB splitting we can run into quadratic case, so performance is quite
2674 important and knowing that the tables are big enough, change_bb_for_stmt
2675 can inline as leaf function. */
2677 change_bb_for_stmt (tree t, basic_block bb)
2679 get_stmt_ann (t)->bb = bb;
2680 if (TREE_CODE (t) == LABEL_EXPR)
2681 VEC_replace (basic_block, label_to_block_map,
2682 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2685 /* Finds iterator for STMT. */
2687 extern block_stmt_iterator
2688 bsi_for_stmt (tree stmt)
2690 block_stmt_iterator bsi;
2692 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2693 if (bsi_stmt (bsi) == stmt)
2699 /* Mark statement T as modified, and update it. */
2701 update_modified_stmts (tree t)
2703 if (!ssa_operands_active ())
2705 if (TREE_CODE (t) == STATEMENT_LIST)
2707 tree_stmt_iterator i;
2709 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2711 stmt = tsi_stmt (i);
2712 update_stmt_if_modified (stmt);
2716 update_stmt_if_modified (t);
2719 /* Insert statement (or statement list) T before the statement
2720 pointed-to by iterator I. M specifies how to update iterator I
2721 after insertion (see enum bsi_iterator_update). */
2724 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2726 set_bb_for_stmt (t, i->bb);
2727 update_modified_stmts (t);
2728 tsi_link_before (&i->tsi, t, m);
2732 /* Insert statement (or statement list) T after the statement
2733 pointed-to by iterator I. M specifies how to update iterator I
2734 after insertion (see enum bsi_iterator_update). */
2737 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2739 set_bb_for_stmt (t, i->bb);
2740 update_modified_stmts (t);
2741 tsi_link_after (&i->tsi, t, m);
2745 /* Remove the statement pointed to by iterator I. The iterator is updated
2746 to the next statement.
2748 When REMOVE_EH_INFO is true we remove the statement pointed to by
2749 iterator I from the EH tables. Otherwise we do not modify the EH
2752 Generally, REMOVE_EH_INFO should be true when the statement is going to
2753 be removed from the IL and not reinserted elsewhere. */
2756 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2758 tree t = bsi_stmt (*i);
2759 set_bb_for_stmt (t, NULL);
2760 delink_stmt_imm_use (t);
2761 tsi_delink (&i->tsi);
2762 mark_stmt_modified (t);
2765 remove_stmt_from_eh_region (t);
2766 gimple_remove_stmt_histograms (cfun, t);
2771 /* Move the statement at FROM so it comes right after the statement at TO. */
2774 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2776 tree stmt = bsi_stmt (*from);
2777 bsi_remove (from, false);
2778 /* We must have BSI_NEW_STMT here, as bsi_move_after is sometimes used to
2779 move statements to an empty block. */
2780 bsi_insert_after (to, stmt, BSI_NEW_STMT);
2784 /* Move the statement at FROM so it comes right before the statement at TO. */
2787 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2789 tree stmt = bsi_stmt (*from);
2790 bsi_remove (from, false);
2791 /* For consistency with bsi_move_after, it might be better to have
2792 BSI_NEW_STMT here; however, that breaks several places that expect
2793 that TO does not change. */
2794 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2798 /* Move the statement at FROM to the end of basic block BB. */
2801 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2803 block_stmt_iterator last = bsi_last (bb);
2805 /* Have to check bsi_end_p because it could be an empty block. */
2806 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2807 bsi_move_before (from, &last);
2809 bsi_move_after (from, &last);
2813 /* Replace the contents of the statement pointed to by iterator BSI
2814 with STMT. If UPDATE_EH_INFO is true, the exception handling
2815 information of the original statement is moved to the new statement. */
2818 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2821 tree orig_stmt = bsi_stmt (*bsi);
2823 if (stmt == orig_stmt)
2825 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2826 set_bb_for_stmt (stmt, bsi->bb);
2828 /* Preserve EH region information from the original statement, if
2829 requested by the caller. */
2832 eh_region = lookup_stmt_eh_region (orig_stmt);
2835 remove_stmt_from_eh_region (orig_stmt);
2836 add_stmt_to_eh_region (stmt, eh_region);
2840 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2841 gimple_remove_stmt_histograms (cfun, orig_stmt);
2842 delink_stmt_imm_use (orig_stmt);
2843 *bsi_stmt_ptr (*bsi) = stmt;
2844 mark_stmt_modified (stmt);
2845 update_modified_stmts (stmt);
2849 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2850 is made to place the statement in an existing basic block, but
2851 sometimes that isn't possible. When it isn't possible, the edge is
2852 split and the statement is added to the new block.
2854 In all cases, the returned *BSI points to the correct location. The
2855 return value is true if insertion should be done after the location,
2856 or false if it should be done before the location. If new basic block
2857 has to be created, it is stored in *NEW_BB. */
2860 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2861 basic_block *new_bb)
2863 basic_block dest, src;
2869 /* If the destination has one predecessor which has no PHI nodes,
2870 insert there. Except for the exit block.
2872 The requirement for no PHI nodes could be relaxed. Basically we
2873 would have to examine the PHIs to prove that none of them used
2874 the value set by the statement we want to insert on E. That
2875 hardly seems worth the effort. */
2876 if (single_pred_p (dest)
2877 && ! phi_nodes (dest)
2878 && dest != EXIT_BLOCK_PTR)
2880 *bsi = bsi_start (dest);
2881 if (bsi_end_p (*bsi))
2884 /* Make sure we insert after any leading labels. */
2885 tmp = bsi_stmt (*bsi);
2886 while (TREE_CODE (tmp) == LABEL_EXPR)
2889 if (bsi_end_p (*bsi))
2891 tmp = bsi_stmt (*bsi);
2894 if (bsi_end_p (*bsi))
2896 *bsi = bsi_last (dest);
2903 /* If the source has one successor, the edge is not abnormal and
2904 the last statement does not end a basic block, insert there.
2905 Except for the entry block. */
2907 if ((e->flags & EDGE_ABNORMAL) == 0
2908 && single_succ_p (src)
2909 && src != ENTRY_BLOCK_PTR)
2911 *bsi = bsi_last (src);
2912 if (bsi_end_p (*bsi))
2915 tmp = bsi_stmt (*bsi);
2916 if (!stmt_ends_bb_p (tmp))
2919 /* Insert code just before returning the value. We may need to decompose
2920 the return in the case it contains non-trivial operand. */
2921 if (TREE_CODE (tmp) == RETURN_EXPR)
2923 tree op = TREE_OPERAND (tmp, 0);
2924 if (op && !is_gimple_val (op))
2926 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
2927 bsi_insert_before (bsi, op, BSI_NEW_STMT);
2928 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
2935 /* Otherwise, create a new basic block, and split this edge. */
2936 dest = split_edge (e);
2939 e = single_pred_edge (dest);
2944 /* This routine will commit all pending edge insertions, creating any new
2945 basic blocks which are necessary. */
2948 bsi_commit_edge_inserts (void)
2954 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
2957 FOR_EACH_EDGE (e, ei, bb->succs)
2958 bsi_commit_one_edge_insert (e, NULL);
2962 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2963 to this block, otherwise set it to NULL. */
2966 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
2970 if (PENDING_STMT (e))
2972 block_stmt_iterator bsi;
2973 tree stmt = PENDING_STMT (e);
2975 PENDING_STMT (e) = NULL_TREE;
2977 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
2978 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
2980 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
2985 /* Add STMT to the pending list of edge E. No actual insertion is
2986 made until a call to bsi_commit_edge_inserts () is made. */
2989 bsi_insert_on_edge (edge e, tree stmt)
2991 append_to_statement_list (stmt, &PENDING_STMT (e));
2994 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
2995 block has to be created, it is returned. */
2998 bsi_insert_on_edge_immediate (edge e, tree stmt)
3000 block_stmt_iterator bsi;
3001 basic_block new_bb = NULL;
3003 gcc_assert (!PENDING_STMT (e));
3005 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3006 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3008 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3013 /*---------------------------------------------------------------------------
3014 Tree specific functions for CFG manipulation
3015 ---------------------------------------------------------------------------*/
3017 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3020 reinstall_phi_args (edge new_edge, edge old_edge)
3024 if (!PENDING_STMT (old_edge))
3027 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3029 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3031 tree result = TREE_PURPOSE (var);
3032 tree arg = TREE_VALUE (var);
3034 gcc_assert (result == PHI_RESULT (phi));
3036 add_phi_arg (phi, arg, new_edge);
3039 PENDING_STMT (old_edge) = NULL;
3042 /* Returns the basic block after which the new basic block created
3043 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3044 near its "logical" location. This is of most help to humans looking
3045 at debugging dumps. */
3048 split_edge_bb_loc (edge edge_in)
3050 basic_block dest = edge_in->dest;
3052 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3053 return edge_in->src;
3055 return dest->prev_bb;
3058 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3059 Abort on abnormal edges. */
3062 tree_split_edge (edge edge_in)
3064 basic_block new_bb, after_bb, dest;
3067 /* Abnormal edges cannot be split. */
3068 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3070 dest = edge_in->dest;
3072 after_bb = split_edge_bb_loc (edge_in);
3074 new_bb = create_empty_bb (after_bb);
3075 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3076 new_bb->count = edge_in->count;
3077 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3078 new_edge->probability = REG_BR_PROB_BASE;
3079 new_edge->count = edge_in->count;
3081 e = redirect_edge_and_branch (edge_in, new_bb);
3082 gcc_assert (e == edge_in);
3083 reinstall_phi_args (new_edge, e);
3088 /* Callback for walk_tree, check that all elements with address taken are
3089 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3090 inside a PHI node. */
3093 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3096 bool in_phi = (data != NULL);
3101 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3102 #define CHECK_OP(N, MSG) \
3103 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3104 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3106 switch (TREE_CODE (t))
3109 if (SSA_NAME_IN_FREE_LIST (t))
3111 error ("SSA name in freelist but still referenced");
3117 x = fold (ASSERT_EXPR_COND (t));
3118 if (x == boolean_false_node)
3120 error ("ASSERT_EXPR with an always-false condition");
3128 case GIMPLE_MODIFY_STMT:
3129 x = GIMPLE_STMT_OPERAND (t, 0);
3130 if (TREE_CODE (x) == BIT_FIELD_REF
3131 && is_gimple_reg (TREE_OPERAND (x, 0)))
3133 error ("GIMPLE register modified with BIT_FIELD_REF");
3142 bool old_side_effects;
3145 bool new_side_effects;
3147 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3148 dead PHIs that take the address of something. But if the PHI
3149 result is dead, the fact that it takes the address of anything
3150 is irrelevant. Because we can not tell from here if a PHI result
3151 is dead, we just skip this check for PHIs altogether. This means
3152 we may be missing "valid" checks, but what can you do?
3153 This was PR19217. */
3157 old_invariant = TREE_INVARIANT (t);
3158 old_constant = TREE_CONSTANT (t);
3159 old_side_effects = TREE_SIDE_EFFECTS (t);
3161 recompute_tree_invariant_for_addr_expr (t);
3162 new_invariant = TREE_INVARIANT (t);
3163 new_side_effects = TREE_SIDE_EFFECTS (t);
3164 new_constant = TREE_CONSTANT (t);
3166 if (old_invariant != new_invariant)
3168 error ("invariant not recomputed when ADDR_EXPR changed");
3172 if (old_constant != new_constant)
3174 error ("constant not recomputed when ADDR_EXPR changed");
3177 if (old_side_effects != new_side_effects)
3179 error ("side effects not recomputed when ADDR_EXPR changed");
3183 /* Skip any references (they will be checked when we recurse down the
3184 tree) and ensure that any variable used as a prefix is marked
3186 for (x = TREE_OPERAND (t, 0);
3187 handled_component_p (x);
3188 x = TREE_OPERAND (x, 0))
3191 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3193 if (!TREE_ADDRESSABLE (x))
3195 error ("address taken, but ADDRESSABLE bit not set");
3202 x = COND_EXPR_COND (t);
3203 if (!INTEGRAL_TYPE_P (TREE_TYPE (x)))
3205 error ("non-integral used in condition");
3208 if (!is_gimple_condexpr (x))
3210 error ("invalid conditional operand");
3217 case FIX_TRUNC_EXPR:
3222 case NON_LVALUE_EXPR:
3223 case TRUTH_NOT_EXPR:
3224 CHECK_OP (0, "invalid operand to unary operator");
3231 case ARRAY_RANGE_REF:
3233 case VIEW_CONVERT_EXPR:
3234 /* We have a nest of references. Verify that each of the operands
3235 that determine where to reference is either a constant or a variable,
3236 verify that the base is valid, and then show we've already checked
3238 while (handled_component_p (t))
3240 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3241 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3242 else if (TREE_CODE (t) == ARRAY_REF
3243 || TREE_CODE (t) == ARRAY_RANGE_REF)
3245 CHECK_OP (1, "invalid array index");
3246 if (TREE_OPERAND (t, 2))
3247 CHECK_OP (2, "invalid array lower bound");
3248 if (TREE_OPERAND (t, 3))
3249 CHECK_OP (3, "invalid array stride");
3251 else if (TREE_CODE (t) == BIT_FIELD_REF)
3253 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3254 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3257 t = TREE_OPERAND (t, 0);
3260 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3262 error ("invalid reference prefix");
3269 /* PLUS_EXPR and MINUS_EXPR don't work on pointers, they should be done using
3270 POINTER_PLUS_EXPR. */
3271 if (POINTER_TYPE_P (TREE_TYPE (t)))
3273 error ("invalid operand to plus/minus, type is a pointer");
3276 CHECK_OP (0, "invalid operand to binary operator");
3277 CHECK_OP (1, "invalid operand to binary operator");
3280 case POINTER_PLUS_EXPR:
3281 /* Check to make sure the first operand is a pointer or reference type. */
3282 if (!POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (t, 0))))
3284 error ("invalid operand to pointer plus, first operand is not a pointer");
3287 /* Check to make sure the second operand is an integer with type of
3289 if (!useless_type_conversion_p (sizetype,
3290 TREE_TYPE (TREE_OPERAND (t, 1))))
3292 error ("invalid operand to pointer plus, second operand is not an "
3293 "integer with type of sizetype.");
3303 case UNORDERED_EXPR:
3312 case TRUNC_DIV_EXPR:
3314 case FLOOR_DIV_EXPR:
3315 case ROUND_DIV_EXPR:
3316 case TRUNC_MOD_EXPR:
3318 case FLOOR_MOD_EXPR:
3319 case ROUND_MOD_EXPR:
3321 case EXACT_DIV_EXPR:
3331 CHECK_OP (0, "invalid operand to binary operator");
3332 CHECK_OP (1, "invalid operand to binary operator");
3336 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3349 /* Verify STMT, return true if STMT is not in GIMPLE form.
3350 TODO: Implement type checking. */
3353 verify_stmt (tree stmt, bool last_in_block)
3357 if (OMP_DIRECTIVE_P (stmt))
3359 /* OpenMP directives are validated by the FE and never operated
3360 on by the optimizers. Furthermore, OMP_FOR may contain
3361 non-gimple expressions when the main index variable has had
3362 its address taken. This does not affect the loop itself
3363 because the header of an OMP_FOR is merely used to determine
3364 how to setup the parallel iteration. */
3368 if (!is_gimple_stmt (stmt))
3370 error ("is not a valid GIMPLE statement");
3374 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3377 debug_generic_stmt (addr);
3381 /* If the statement is marked as part of an EH region, then it is
3382 expected that the statement could throw. Verify that when we
3383 have optimizations that simplify statements such that we prove
3384 that they cannot throw, that we update other data structures
3386 if (lookup_stmt_eh_region (stmt) >= 0)
3388 if (!tree_could_throw_p (stmt))
3390 error ("statement marked for throw, but doesn%'t");
3393 if (!last_in_block && tree_can_throw_internal (stmt))
3395 error ("statement marked for throw in middle of block");
3403 debug_generic_stmt (stmt);
3408 /* Return true when the T can be shared. */
3411 tree_node_can_be_shared (tree t)
3413 if (IS_TYPE_OR_DECL_P (t)
3414 || is_gimple_min_invariant (t)
3415 || TREE_CODE (t) == SSA_NAME
3416 || t == error_mark_node
3417 || TREE_CODE (t) == IDENTIFIER_NODE)
3420 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3423 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3424 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3425 || TREE_CODE (t) == COMPONENT_REF
3426 || TREE_CODE (t) == REALPART_EXPR
3427 || TREE_CODE (t) == IMAGPART_EXPR)
3428 t = TREE_OPERAND (t, 0);
3437 /* Called via walk_trees. Verify tree sharing. */
3440 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3442 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3444 if (tree_node_can_be_shared (*tp))
3446 *walk_subtrees = false;
3450 if (pointer_set_insert (visited, *tp))
3457 /* Helper function for verify_gimple_tuples. */
3460 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3461 void *data ATTRIBUTE_UNUSED)
3463 switch (TREE_CODE (*tp))
3466 error ("unexpected non-tuple");
3476 /* Verify that there are no trees that should have been converted to
3477 gimple tuples. Return true if T contains a node that should have
3478 been converted to a gimple tuple, but hasn't. */
3481 verify_gimple_tuples (tree t)
3483 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3486 static bool eh_error_found;
3488 verify_eh_throw_stmt_node (void **slot, void *data)
3490 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3491 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3493 if (!pointer_set_contains (visited, node->stmt))
3495 error ("Dead STMT in EH table");
3496 debug_generic_stmt (node->stmt);
3497 eh_error_found = true;
3502 /* Verify the GIMPLE statement chain. */
3508 block_stmt_iterator bsi;
3510 struct pointer_set_t *visited, *visited_stmts;
3513 timevar_push (TV_TREE_STMT_VERIFY);
3514 visited = pointer_set_create ();
3515 visited_stmts = pointer_set_create ();
3522 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3524 int phi_num_args = PHI_NUM_ARGS (phi);
3526 pointer_set_insert (visited_stmts, phi);
3527 if (bb_for_stmt (phi) != bb)
3529 error ("bb_for_stmt (phi) is set to a wrong basic block");
3533 for (i = 0; i < phi_num_args; i++)
3535 tree t = PHI_ARG_DEF (phi, i);
3538 /* Addressable variables do have SSA_NAMEs but they
3539 are not considered gimple values. */
3540 if (TREE_CODE (t) != SSA_NAME
3541 && TREE_CODE (t) != FUNCTION_DECL
3542 && !is_gimple_val (t))
3544 error ("PHI def is not a GIMPLE value");
3545 debug_generic_stmt (phi);
3546 debug_generic_stmt (t);
3550 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3553 debug_generic_stmt (addr);
3557 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3560 error ("incorrect sharing of tree nodes");
3561 debug_generic_stmt (phi);
3562 debug_generic_stmt (addr);
3568 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3570 tree stmt = bsi_stmt (bsi);
3572 pointer_set_insert (visited_stmts, stmt);
3573 err |= verify_gimple_tuples (stmt);
3575 if (bb_for_stmt (stmt) != bb)
3577 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3582 err |= verify_stmt (stmt, bsi_end_p (bsi));
3583 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3586 error ("incorrect sharing of tree nodes");
3587 debug_generic_stmt (stmt);
3588 debug_generic_stmt (addr);
3593 eh_error_found = false;
3594 if (get_eh_throw_stmt_table (cfun))
3595 htab_traverse (get_eh_throw_stmt_table (cfun),
3596 verify_eh_throw_stmt_node,
3599 if (err | eh_error_found)
3600 internal_error ("verify_stmts failed");
3602 pointer_set_destroy (visited);
3603 pointer_set_destroy (visited_stmts);
3604 verify_histograms ();
3605 timevar_pop (TV_TREE_STMT_VERIFY);
3609 /* Verifies that the flow information is OK. */
3612 tree_verify_flow_info (void)
3616 block_stmt_iterator bsi;
3621 if (ENTRY_BLOCK_PTR->il.tree)
3623 error ("ENTRY_BLOCK has IL associated with it");
3627 if (EXIT_BLOCK_PTR->il.tree)
3629 error ("EXIT_BLOCK has IL associated with it");
3633 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3634 if (e->flags & EDGE_FALLTHRU)
3636 error ("fallthru to exit from bb %d", e->src->index);
3642 bool found_ctrl_stmt = false;
3646 /* Skip labels on the start of basic block. */
3647 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3649 tree prev_stmt = stmt;
3651 stmt = bsi_stmt (bsi);
3653 if (TREE_CODE (stmt) != LABEL_EXPR)
3656 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3658 error ("nonlocal label ");
3659 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3660 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3665 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3668 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3669 fprintf (stderr, " to block does not match in bb %d",
3674 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3675 != current_function_decl)
3678 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3679 fprintf (stderr, " has incorrect context in bb %d",
3685 /* Verify that body of basic block BB is free of control flow. */
3686 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3688 tree stmt = bsi_stmt (bsi);
3690 if (found_ctrl_stmt)
3692 error ("control flow in the middle of basic block %d",
3697 if (stmt_ends_bb_p (stmt))
3698 found_ctrl_stmt = true;
3700 if (TREE_CODE (stmt) == LABEL_EXPR)
3703 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3704 fprintf (stderr, " in the middle of basic block %d", bb->index);
3709 bsi = bsi_last (bb);
3710 if (bsi_end_p (bsi))
3713 stmt = bsi_stmt (bsi);
3715 err |= verify_eh_edges (stmt);
3717 if (is_ctrl_stmt (stmt))
3719 FOR_EACH_EDGE (e, ei, bb->succs)
3720 if (e->flags & EDGE_FALLTHRU)
3722 error ("fallthru edge after a control statement in bb %d",
3728 if (TREE_CODE (stmt) != COND_EXPR)
3730 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3731 after anything else but if statement. */
3732 FOR_EACH_EDGE (e, ei, bb->succs)
3733 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3735 error ("true/false edge after a non-COND_EXPR in bb %d",
3741 switch (TREE_CODE (stmt))
3748 if (COND_EXPR_THEN (stmt) != NULL_TREE
3749 || COND_EXPR_ELSE (stmt) != NULL_TREE)
3751 error ("COND_EXPR with code in branches at the end of bb %d",
3756 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3758 if (!true_edge || !false_edge
3759 || !(true_edge->flags & EDGE_TRUE_VALUE)
3760 || !(false_edge->flags & EDGE_FALSE_VALUE)
3761 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3762 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3763 || EDGE_COUNT (bb->succs) >= 3)
3765 error ("wrong outgoing edge flags at end of bb %d",
3773 if (simple_goto_p (stmt))
3775 error ("explicit goto at end of bb %d", bb->index);
3780 /* FIXME. We should double check that the labels in the
3781 destination blocks have their address taken. */
3782 FOR_EACH_EDGE (e, ei, bb->succs)
3783 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3784 | EDGE_FALSE_VALUE))
3785 || !(e->flags & EDGE_ABNORMAL))
3787 error ("wrong outgoing edge flags at end of bb %d",
3795 if (!single_succ_p (bb)
3796 || (single_succ_edge (bb)->flags
3797 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3798 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3800 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3803 if (single_succ (bb) != EXIT_BLOCK_PTR)
3805 error ("return edge does not point to exit in bb %d",
3818 vec = SWITCH_LABELS (stmt);
3819 n = TREE_VEC_LENGTH (vec);
3821 /* Mark all the destination basic blocks. */
3822 for (i = 0; i < n; ++i)
3824 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3825 basic_block label_bb = label_to_block (lab);
3827 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3828 label_bb->aux = (void *)1;
3831 /* Verify that the case labels are sorted. */
3832 prev = TREE_VEC_ELT (vec, 0);
3833 for (i = 1; i < n - 1; ++i)
3835 tree c = TREE_VEC_ELT (vec, i);
3838 error ("found default case not at end of case vector");
3842 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3844 error ("case labels not sorted: ");
3845 print_generic_expr (stderr, prev, 0);
3846 fprintf (stderr," is greater than ");
3847 print_generic_expr (stderr, c, 0);
3848 fprintf (stderr," but comes before it.\n");
3853 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3855 error ("no default case found at end of case vector");
3859 FOR_EACH_EDGE (e, ei, bb->succs)
3863 error ("extra outgoing edge %d->%d",
3864 bb->index, e->dest->index);
3867 e->dest->aux = (void *)2;
3868 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3869 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3871 error ("wrong outgoing edge flags at end of bb %d",
3877 /* Check that we have all of them. */
3878 for (i = 0; i < n; ++i)
3880 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3881 basic_block label_bb = label_to_block (lab);
3883 if (label_bb->aux != (void *)2)
3885 error ("missing edge %i->%i",
3886 bb->index, label_bb->index);
3891 FOR_EACH_EDGE (e, ei, bb->succs)
3892 e->dest->aux = (void *)0;
3899 if (dom_info_state (CDI_DOMINATORS) >= DOM_NO_FAST_QUERY)
3900 verify_dominators (CDI_DOMINATORS);
3906 /* Updates phi nodes after creating a forwarder block joined
3907 by edge FALLTHRU. */
3910 tree_make_forwarder_block (edge fallthru)
3914 basic_block dummy, bb;
3915 tree phi, new_phi, var;
3917 dummy = fallthru->src;
3918 bb = fallthru->dest;
3920 if (single_pred_p (bb))
3923 /* If we redirected a branch we must create new PHI nodes at the
3925 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3927 var = PHI_RESULT (phi);
3928 new_phi = create_phi_node (var, bb);
3929 SSA_NAME_DEF_STMT (var) = new_phi;
3930 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3931 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3934 /* Ensure that the PHI node chain is in the same order. */
3935 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3937 /* Add the arguments we have stored on edges. */
3938 FOR_EACH_EDGE (e, ei, bb->preds)
3943 flush_pending_stmts (e);
3948 /* Return a non-special label in the head of basic block BLOCK.
3949 Create one if it doesn't exist. */
3952 tree_block_label (basic_block bb)
3954 block_stmt_iterator i, s = bsi_start (bb);
3958 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
3960 stmt = bsi_stmt (i);
3961 if (TREE_CODE (stmt) != LABEL_EXPR)
3963 label = LABEL_EXPR_LABEL (stmt);
3964 if (!DECL_NONLOCAL (label))
3967 bsi_move_before (&i, &s);
3972 label = create_artificial_label ();
3973 stmt = build1 (LABEL_EXPR, void_type_node, label);
3974 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
3979 /* Attempt to perform edge redirection by replacing a possibly complex
3980 jump instruction by a goto or by removing the jump completely.
3981 This can apply only if all edges now point to the same block. The
3982 parameters and return values are equivalent to
3983 redirect_edge_and_branch. */
3986 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
3988 basic_block src = e->src;
3989 block_stmt_iterator b;
3992 /* We can replace or remove a complex jump only when we have exactly
3994 if (EDGE_COUNT (src->succs) != 2
3995 /* Verify that all targets will be TARGET. Specifically, the
3996 edge that is not E must also go to TARGET. */
3997 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4003 stmt = bsi_stmt (b);
4005 if (TREE_CODE (stmt) == COND_EXPR
4006 || TREE_CODE (stmt) == SWITCH_EXPR)
4008 bsi_remove (&b, true);
4009 e = ssa_redirect_edge (e, target);
4010 e->flags = EDGE_FALLTHRU;
4018 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4019 edge representing the redirected branch. */
4022 tree_redirect_edge_and_branch (edge e, basic_block dest)
4024 basic_block bb = e->src;
4025 block_stmt_iterator bsi;
4029 if (e->flags & EDGE_ABNORMAL)
4032 if (e->src != ENTRY_BLOCK_PTR
4033 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4036 if (e->dest == dest)
4039 bsi = bsi_last (bb);
4040 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4042 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4045 /* For COND_EXPR, we only need to redirect the edge. */
4049 /* No non-abnormal edges should lead from a non-simple goto, and
4050 simple ones should be represented implicitly. */
4055 tree cases = get_cases_for_edge (e, stmt);
4056 tree label = tree_block_label (dest);
4058 /* If we have a list of cases associated with E, then use it
4059 as it's a lot faster than walking the entire case vector. */
4062 edge e2 = find_edge (e->src, dest);
4069 CASE_LABEL (cases) = label;
4070 cases = TREE_CHAIN (cases);
4073 /* If there was already an edge in the CFG, then we need
4074 to move all the cases associated with E to E2. */
4077 tree cases2 = get_cases_for_edge (e2, stmt);
4079 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4080 TREE_CHAIN (cases2) = first;
4085 tree vec = SWITCH_LABELS (stmt);
4086 size_t i, n = TREE_VEC_LENGTH (vec);
4088 for (i = 0; i < n; i++)
4090 tree elt = TREE_VEC_ELT (vec, i);
4092 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4093 CASE_LABEL (elt) = label;
4101 bsi_remove (&bsi, true);
4102 e->flags |= EDGE_FALLTHRU;
4106 /* Otherwise it must be a fallthru edge, and we don't need to
4107 do anything besides redirecting it. */
4108 gcc_assert (e->flags & EDGE_FALLTHRU);
4112 /* Update/insert PHI nodes as necessary. */
4114 /* Now update the edges in the CFG. */
4115 e = ssa_redirect_edge (e, dest);
4120 /* Returns true if it is possible to remove edge E by redirecting
4121 it to the destination of the other edge from E->src. */
4124 tree_can_remove_branch_p (edge e)
4126 if (e->flags & EDGE_ABNORMAL)
4132 /* Simple wrapper, as we can always redirect fallthru edges. */
4135 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4137 e = tree_redirect_edge_and_branch (e, dest);
4144 /* Splits basic block BB after statement STMT (but at least after the
4145 labels). If STMT is NULL, BB is split just after the labels. */
4148 tree_split_block (basic_block bb, void *stmt)
4150 block_stmt_iterator bsi;
4151 tree_stmt_iterator tsi_tgt;
4157 new_bb = create_empty_bb (bb);
4159 /* Redirect the outgoing edges. */
4160 new_bb->succs = bb->succs;
4162 FOR_EACH_EDGE (e, ei, new_bb->succs)
4165 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4168 /* Move everything from BSI to the new basic block. */
4169 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4171 act = bsi_stmt (bsi);
4172 if (TREE_CODE (act) == LABEL_EXPR)
4185 if (bsi_end_p (bsi))
4188 /* Split the statement list - avoid re-creating new containers as this
4189 brings ugly quadratic memory consumption in the inliner.
4190 (We are still quadratic since we need to update stmt BB pointers,
4192 list = tsi_split_statement_list_before (&bsi.tsi);
4193 set_bb_stmt_list (new_bb, list);
4194 for (tsi_tgt = tsi_start (list);
4195 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4196 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4202 /* Moves basic block BB after block AFTER. */
4205 tree_move_block_after (basic_block bb, basic_block after)
4207 if (bb->prev_bb == after)
4211 link_block (bb, after);
4217 /* Return true if basic_block can be duplicated. */
4220 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4226 /* Create a duplicate of the basic block BB. NOTE: This does not
4227 preserve SSA form. */
4230 tree_duplicate_bb (basic_block bb)
4233 block_stmt_iterator bsi, bsi_tgt;
4236 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4238 /* Copy the PHI nodes. We ignore PHI node arguments here because
4239 the incoming edges have not been setup yet. */
4240 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4242 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4243 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4246 /* Keep the chain of PHI nodes in the same order so that they can be
4247 updated by ssa_redirect_edge. */
4248 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4250 bsi_tgt = bsi_start (new_bb);
4251 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4253 def_operand_p def_p;
4254 ssa_op_iter op_iter;
4258 stmt = bsi_stmt (bsi);
4259 if (TREE_CODE (stmt) == LABEL_EXPR)
4262 /* Create a new copy of STMT and duplicate STMT's virtual
4264 copy = unshare_expr (stmt);
4265 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4266 copy_virtual_operands (copy, stmt);
4267 region = lookup_stmt_eh_region (stmt);
4269 add_stmt_to_eh_region (copy, region);
4270 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4272 /* Create new names for all the definitions created by COPY and
4273 add replacement mappings for each new name. */
4274 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4275 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4282 /* Basic block BB_COPY was created by code duplication. Add phi node
4283 arguments for edges going out of BB_COPY. The blocks that were
4284 duplicated have BB_DUPLICATED set. */
4287 add_phi_args_after_copy_bb (basic_block bb_copy)
4289 basic_block bb, dest;
4292 tree phi, phi_copy, phi_next, def;
4294 bb = get_bb_original (bb_copy);
4296 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4298 if (!phi_nodes (e_copy->dest))
4301 if (e_copy->dest->flags & BB_DUPLICATED)
4302 dest = get_bb_original (e_copy->dest);
4304 dest = e_copy->dest;
4306 e = find_edge (bb, dest);
4309 /* During loop unrolling the target of the latch edge is copied.
4310 In this case we are not looking for edge to dest, but to
4311 duplicated block whose original was dest. */
4312 FOR_EACH_EDGE (e, ei, bb->succs)
4313 if ((e->dest->flags & BB_DUPLICATED)
4314 && get_bb_original (e->dest) == dest)
4317 gcc_assert (e != NULL);
4320 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4322 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4324 phi_next = PHI_CHAIN (phi);
4325 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4326 add_phi_arg (phi_copy, def, e_copy);
4331 /* Blocks in REGION_COPY array of length N_REGION were created by
4332 duplication of basic blocks. Add phi node arguments for edges
4333 going from these blocks. */
4336 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4340 for (i = 0; i < n_region; i++)
4341 region_copy[i]->flags |= BB_DUPLICATED;
4343 for (i = 0; i < n_region; i++)
4344 add_phi_args_after_copy_bb (region_copy[i]);
4346 for (i = 0; i < n_region; i++)
4347 region_copy[i]->flags &= ~BB_DUPLICATED;
4350 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4351 important exit edge EXIT. By important we mean that no SSA name defined
4352 inside region is live over the other exit edges of the region. All entry
4353 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4354 to the duplicate of the region. SSA form, dominance and loop information
4355 is updated. The new basic blocks are stored to REGION_COPY in the same
4356 order as they had in REGION, provided that REGION_COPY is not NULL.
4357 The function returns false if it is unable to copy the region,
4361 tree_duplicate_sese_region (edge entry, edge exit,
4362 basic_block *region, unsigned n_region,
4363 basic_block *region_copy)
4366 bool free_region_copy = false, copying_header = false;
4367 struct loop *loop = entry->dest->loop_father;
4369 VEC (basic_block, heap) *doms;
4371 int total_freq = 0, entry_freq = 0;
4372 gcov_type total_count = 0, entry_count = 0;
4374 if (!can_copy_bbs_p (region, n_region))
4377 /* Some sanity checking. Note that we do not check for all possible
4378 missuses of the functions. I.e. if you ask to copy something weird,
4379 it will work, but the state of structures probably will not be
4381 for (i = 0; i < n_region; i++)
4383 /* We do not handle subloops, i.e. all the blocks must belong to the
4385 if (region[i]->loop_father != loop)
4388 if (region[i] != entry->dest
4389 && region[i] == loop->header)
4393 set_loop_copy (loop, loop);
4395 /* In case the function is used for loop header copying (which is the primary
4396 use), ensure that EXIT and its copy will be new latch and entry edges. */
4397 if (loop->header == entry->dest)
4399 copying_header = true;
4400 set_loop_copy (loop, loop_outer (loop));
4402 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4405 for (i = 0; i < n_region; i++)
4406 if (region[i] != exit->src
4407 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4413 region_copy = XNEWVEC (basic_block, n_region);
4414 free_region_copy = true;
4417 gcc_assert (!need_ssa_update_p ());
4419 /* Record blocks outside the region that are dominated by something
4422 initialize_original_copy_tables ();
4424 doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region);
4426 if (entry->dest->count)
4428 total_count = entry->dest->count;
4429 entry_count = entry->count;
4430 /* Fix up corner cases, to avoid division by zero or creation of negative
4432 if (entry_count > total_count)
4433 entry_count = total_count;
4437 total_freq = entry->dest->frequency;
4438 entry_freq = EDGE_FREQUENCY (entry);
4439 /* Fix up corner cases, to avoid division by zero or creation of negative
4441 if (total_freq == 0)
4443 else if (entry_freq > total_freq)
4444 entry_freq = total_freq;
4447 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4448 split_edge_bb_loc (entry));
4451 scale_bbs_frequencies_gcov_type (region, n_region,
4452 total_count - entry_count,
4454 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4459 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4461 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4466 loop->header = exit->dest;
4467 loop->latch = exit->src;
4470 /* Redirect the entry and add the phi node arguments. */
4471 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4472 gcc_assert (redirected != NULL);
4473 flush_pending_stmts (entry);
4475 /* Concerning updating of dominators: We must recount dominators
4476 for entry block and its copy. Anything that is outside of the
4477 region, but was dominated by something inside needs recounting as
4479 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4480 VEC_safe_push (basic_block, heap, doms, get_bb_original (entry->dest));
4481 iterate_fix_dominators (CDI_DOMINATORS, doms, false);
4484 /* Add the other PHI node arguments. */
4485 add_phi_args_after_copy (region_copy, n_region);
4487 /* Update the SSA web. */
4488 update_ssa (TODO_update_ssa);
4490 if (free_region_copy)
4493 free_original_copy_tables ();
4498 DEF_VEC_P(basic_block);
4499 DEF_VEC_ALLOC_P(basic_block,heap);
4502 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4503 adding blocks when the dominator traversal reaches EXIT. This
4504 function silently assumes that ENTRY strictly dominates EXIT. */
4507 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4508 VEC(basic_block,heap) **bbs_p)
4512 for (son = first_dom_son (CDI_DOMINATORS, entry);
4514 son = next_dom_son (CDI_DOMINATORS, son))
4516 VEC_safe_push (basic_block, heap, *bbs_p, son);
4518 gather_blocks_in_sese_region (son, exit, bbs_p);
4528 bitmap vars_to_remove;
4529 htab_t new_label_map;
4533 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4534 contained in *TP and change the DECL_CONTEXT of every local
4535 variable referenced in *TP. */
4538 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4540 struct move_stmt_d *p = (struct move_stmt_d *) data;
4544 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4545 TREE_BLOCK (t) = p->block;
4547 if (OMP_DIRECTIVE_P (t)
4548 && TREE_CODE (t) != OMP_RETURN
4549 && TREE_CODE (t) != OMP_CONTINUE)
4551 /* Do not remap variables inside OMP directives. Variables
4552 referenced in clauses and directive header belong to the
4553 parent function and should not be moved into the child
4555 bool save_remap_decls_p = p->remap_decls_p;
4556 p->remap_decls_p = false;
4559 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4561 p->remap_decls_p = save_remap_decls_p;
4563 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4565 if (TREE_CODE (t) == LABEL_DECL)
4567 if (p->new_label_map)
4569 struct tree_map in, *out;
4571 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4576 DECL_CONTEXT (t) = p->to_context;
4578 else if (p->remap_decls_p)
4580 DECL_CONTEXT (t) = p->to_context;
4582 if (TREE_CODE (t) == VAR_DECL)
4584 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4585 f->unexpanded_var_list
4586 = tree_cons (0, t, f->unexpanded_var_list);
4588 /* Mark T to be removed from the original function,
4589 otherwise it will be given a DECL_RTL when the
4590 original function is expanded. */
4591 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4595 else if (TYPE_P (t))
4602 /* Move basic block BB from function CFUN to function DEST_FN. The
4603 block is moved out of the original linked list and placed after
4604 block AFTER in the new list. Also, the block is removed from the
4605 original array of blocks and placed in DEST_FN's array of blocks.
4606 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4607 updated to reflect the moved edges.
4609 On exit, local variables that need to be removed from
4610 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4613 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4614 basic_block after, bool update_edge_count_p,
4615 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4617 struct control_flow_graph *cfg;
4620 block_stmt_iterator si;
4621 struct move_stmt_d d;
4622 unsigned old_len, new_len;
4624 /* Remove BB from dominance structures. */
4625 delete_from_dominance_info (CDI_DOMINATORS, bb);
4627 /* Link BB to the new linked list. */
4628 move_block_after (bb, after);
4630 /* Update the edge count in the corresponding flowgraphs. */
4631 if (update_edge_count_p)
4632 FOR_EACH_EDGE (e, ei, bb->succs)
4634 cfun->cfg->x_n_edges--;
4635 dest_cfun->cfg->x_n_edges++;
4638 /* Remove BB from the original basic block array. */
4639 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4640 cfun->cfg->x_n_basic_blocks--;
4642 /* Grow DEST_CFUN's basic block array if needed. */
4643 cfg = dest_cfun->cfg;
4644 cfg->x_n_basic_blocks++;
4645 if (bb->index >= cfg->x_last_basic_block)
4646 cfg->x_last_basic_block = bb->index + 1;
4648 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4649 if ((unsigned) cfg->x_last_basic_block >= old_len)
4651 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4652 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4656 VEC_replace (basic_block, cfg->x_basic_block_info,
4659 /* The statements in BB need to be associated with a new TREE_BLOCK.
4660 Labels need to be associated with a new label-to-block map. */
4661 memset (&d, 0, sizeof (d));
4662 d.vars_to_remove = vars_to_remove;
4664 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4666 tree stmt = bsi_stmt (si);
4669 d.from_context = cfun->decl;
4670 d.to_context = dest_cfun->decl;
4671 d.remap_decls_p = true;
4672 d.new_label_map = new_label_map;
4673 if (TREE_BLOCK (stmt))
4674 d.block = DECL_INITIAL (dest_cfun->decl);
4676 walk_tree (&stmt, move_stmt_r, &d, NULL);
4678 if (TREE_CODE (stmt) == LABEL_EXPR)
4680 tree label = LABEL_EXPR_LABEL (stmt);
4681 int uid = LABEL_DECL_UID (label);
4683 gcc_assert (uid > -1);
4685 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4686 if (old_len <= (unsigned) uid)
4688 new_len = 3 * uid / 2;
4689 VEC_safe_grow_cleared (basic_block, gc,
4690 cfg->x_label_to_block_map, new_len);
4693 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4694 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4696 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4698 if (uid >= dest_cfun->last_label_uid)
4699 dest_cfun->last_label_uid = uid + 1;
4701 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4702 TREE_OPERAND (stmt, 0) =
4703 build_int_cst (NULL_TREE,
4704 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4707 region = lookup_stmt_eh_region (stmt);
4710 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4711 remove_stmt_from_eh_region (stmt);
4712 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4713 gimple_remove_stmt_histograms (cfun, stmt);
4718 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4719 the outermost EH region. Use REGION as the incoming base EH region. */
4722 find_outermost_region_in_block (struct function *src_cfun,
4723 basic_block bb, int region)
4725 block_stmt_iterator si;
4727 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4729 tree stmt = bsi_stmt (si);
4732 if (TREE_CODE (stmt) == RESX_EXPR)
4733 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4735 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4736 if (stmt_region > 0)
4739 region = stmt_region;
4740 else if (stmt_region != region)
4742 region = eh_region_outermost (src_cfun, stmt_region, region);
4743 gcc_assert (region != -1);
4752 new_label_mapper (tree decl, void *data)
4754 htab_t hash = (htab_t) data;
4758 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4760 m = xmalloc (sizeof (struct tree_map));
4761 m->hash = DECL_UID (decl);
4762 m->base.from = decl;
4763 m->to = create_artificial_label ();
4764 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4766 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4767 gcc_assert (*slot == NULL);
4774 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4775 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4776 single basic block in the original CFG and the new basic block is
4777 returned. DEST_CFUN must not have a CFG yet.
4779 Note that the region need not be a pure SESE region. Blocks inside
4780 the region may contain calls to abort/exit. The only restriction
4781 is that ENTRY_BB should be the only entry point and it must
4784 All local variables referenced in the region are assumed to be in
4785 the corresponding BLOCK_VARS and unexpanded variable lists
4786 associated with DEST_CFUN. */
4789 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4790 basic_block exit_bb)
4792 VEC(basic_block,heap) *bbs;
4793 basic_block after, bb, *entry_pred, *exit_succ;
4794 struct function *saved_cfun;
4795 int *entry_flag, *exit_flag, eh_offset;
4796 unsigned i, num_entry_edges, num_exit_edges;
4799 bitmap vars_to_remove;
4800 htab_t new_label_map;
4804 /* Collect all the blocks in the region. Manually add ENTRY_BB
4805 because it won't be added by dfs_enumerate_from. */
4806 calculate_dominance_info (CDI_DOMINATORS);
4808 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4810 gcc_assert (entry_bb != exit_bb
4812 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4815 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4816 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4818 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4819 the predecessor edges to ENTRY_BB and the successor edges to
4820 EXIT_BB so that we can re-attach them to the new basic block that
4821 will replace the region. */
4822 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4823 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4824 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4826 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4828 entry_flag[i] = e->flags;
4829 entry_pred[i++] = e->src;
4835 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4836 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4837 sizeof (basic_block));
4838 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4840 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4842 exit_flag[i] = e->flags;
4843 exit_succ[i++] = e->dest;
4854 /* Switch context to the child function to initialize DEST_FN's CFG. */
4855 gcc_assert (dest_cfun->cfg == NULL);
4858 init_empty_tree_cfg ();
4860 /* Initialize EH information for the new function. */
4862 new_label_map = NULL;
4867 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4868 region = find_outermost_region_in_block (saved_cfun, bb, region);
4870 init_eh_for_function ();
4873 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4874 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4875 new_label_map, region, 0);
4881 /* Move blocks from BBS into DEST_CFUN. */
4882 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4883 after = dest_cfun->cfg->x_entry_block_ptr;
4884 vars_to_remove = BITMAP_ALLOC (NULL);
4885 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4887 /* No need to update edge counts on the last block. It has
4888 already been updated earlier when we detached the region from
4889 the original CFG. */
4890 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4891 new_label_map, eh_offset);
4896 htab_delete (new_label_map);
4898 /* Remove the variables marked in VARS_TO_REMOVE from
4899 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4900 DECL_RTL in the context of CFUN. */
4901 if (!bitmap_empty_p (vars_to_remove))
4905 for (p = &cfun->unexpanded_var_list; *p; )
4907 tree var = TREE_VALUE (*p);
4908 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4910 *p = TREE_CHAIN (*p);
4914 p = &TREE_CHAIN (*p);
4918 BITMAP_FREE (vars_to_remove);
4920 /* Rewire the entry and exit blocks. The successor to the entry
4921 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4922 the child function. Similarly, the predecessor of DEST_FN's
4923 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4924 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4925 various CFG manipulation function get to the right CFG.
4927 FIXME, this is silly. The CFG ought to become a parameter to
4930 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4932 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4935 /* Back in the original function, the SESE region has disappeared,
4936 create a new basic block in its place. */
4937 bb = create_empty_bb (entry_pred[0]);
4938 for (i = 0; i < num_entry_edges; i++)
4939 make_edge (entry_pred[i], bb, entry_flag[i]);
4941 for (i = 0; i < num_exit_edges; i++)
4942 make_edge (bb, exit_succ[i], exit_flag[i]);
4951 free_dominance_info (CDI_DOMINATORS);
4952 free_dominance_info (CDI_POST_DOMINATORS);
4953 VEC_free (basic_block, heap, bbs);
4959 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4962 dump_function_to_file (tree fn, FILE *file, int flags)
4964 tree arg, vars, var;
4965 struct function *dsf;
4966 bool ignore_topmost_bind = false, any_var = false;
4969 struct function *saved_cfun;
4971 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
4973 arg = DECL_ARGUMENTS (fn);
4976 print_generic_expr (file, arg, dump_flags);
4977 if (TREE_CHAIN (arg))
4978 fprintf (file, ", ");
4979 arg = TREE_CHAIN (arg);
4981 fprintf (file, ")\n");
4983 dsf = DECL_STRUCT_FUNCTION (fn);
4984 if (dsf && (flags & TDF_DETAILS))
4985 dump_eh_tree (file, dsf);
4987 if (flags & TDF_RAW)
4989 dump_node (fn, TDF_SLIM | flags, file);
4993 /* Switch CFUN to point to FN. */
4995 cfun = DECL_STRUCT_FUNCTION (fn);
4997 /* When GIMPLE is lowered, the variables are no longer available in
4998 BIND_EXPRs, so display them separately. */
4999 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5001 ignore_topmost_bind = true;
5003 fprintf (file, "{\n");
5004 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5006 var = TREE_VALUE (vars);
5008 print_generic_decl (file, var, flags);
5009 fprintf (file, "\n");
5015 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5017 /* Make a CFG based dump. */
5018 check_bb_profile (ENTRY_BLOCK_PTR, file);
5019 if (!ignore_topmost_bind)
5020 fprintf (file, "{\n");
5022 if (any_var && n_basic_blocks)
5023 fprintf (file, "\n");
5026 dump_generic_bb (file, bb, 2, flags);
5028 fprintf (file, "}\n");
5029 check_bb_profile (EXIT_BLOCK_PTR, file);
5035 /* Make a tree based dump. */
5036 chain = DECL_SAVED_TREE (fn);
5038 if (chain && TREE_CODE (chain) == BIND_EXPR)
5040 if (ignore_topmost_bind)
5042 chain = BIND_EXPR_BODY (chain);
5050 if (!ignore_topmost_bind)
5051 fprintf (file, "{\n");
5056 fprintf (file, "\n");
5058 print_generic_stmt_indented (file, chain, flags, indent);
5059 if (ignore_topmost_bind)
5060 fprintf (file, "}\n");
5063 fprintf (file, "\n\n");
5070 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5073 debug_function (tree fn, int flags)
5075 dump_function_to_file (fn, stderr, flags);
5079 /* Pretty print of the loops intermediate representation. */
5080 static void print_loop (FILE *, struct loop *, int);
5081 static void print_pred_bbs (FILE *, basic_block bb);
5082 static void print_succ_bbs (FILE *, basic_block bb);
5085 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5088 print_pred_bbs (FILE *file, basic_block bb)
5093 FOR_EACH_EDGE (e, ei, bb->preds)
5094 fprintf (file, "bb_%d ", e->src->index);
5098 /* Print on FILE the indexes for the successors of basic_block BB. */
5101 print_succ_bbs (FILE *file, basic_block bb)
5106 FOR_EACH_EDGE (e, ei, bb->succs)
5107 fprintf (file, "bb_%d ", e->dest->index);
5111 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5114 print_loop (FILE *file, struct loop *loop, int indent)
5122 s_indent = (char *) alloca ((size_t) indent + 1);
5123 memset ((void *) s_indent, ' ', (size_t) indent);
5124 s_indent[indent] = '\0';
5126 /* Print the loop's header. */
5127 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5129 /* Print the loop's body. */
5130 fprintf (file, "%s{\n", s_indent);
5132 if (bb->loop_father == loop)
5134 /* Print the basic_block's header. */
5135 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5136 print_pred_bbs (file, bb);
5137 fprintf (file, "}, succs = {");
5138 print_succ_bbs (file, bb);
5139 fprintf (file, "})\n");
5141 /* Print the basic_block's body. */
5142 fprintf (file, "%s {\n", s_indent);
5143 tree_dump_bb (bb, file, indent + 4);
5144 fprintf (file, "%s }\n", s_indent);
5147 print_loop (file, loop->inner, indent + 2);
5148 fprintf (file, "%s}\n", s_indent);
5149 print_loop (file, loop->next, indent);
5153 /* Follow a CFG edge from the entry point of the program, and on entry
5154 of a loop, pretty print the loop structure on FILE. */
5157 print_loop_ir (FILE *file)
5161 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5162 if (bb && bb->loop_father)
5163 print_loop (file, bb->loop_father, 0);
5167 /* Debugging loops structure at tree level. */
5170 debug_loop_ir (void)
5172 print_loop_ir (stderr);
5176 /* Return true if BB ends with a call, possibly followed by some
5177 instructions that must stay with the call. Return false,
5181 tree_block_ends_with_call_p (basic_block bb)
5183 block_stmt_iterator bsi = bsi_last (bb);
5184 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5188 /* Return true if BB ends with a conditional branch. Return false,
5192 tree_block_ends_with_condjump_p (basic_block bb)
5194 tree stmt = last_stmt (bb);
5195 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5199 /* Return true if we need to add fake edge to exit at statement T.
5200 Helper function for tree_flow_call_edges_add. */
5203 need_fake_edge_p (tree t)
5207 /* NORETURN and LONGJMP calls already have an edge to exit.
5208 CONST and PURE calls do not need one.
5209 We don't currently check for CONST and PURE here, although
5210 it would be a good idea, because those attributes are
5211 figured out from the RTL in mark_constant_function, and
5212 the counter incrementation code from -fprofile-arcs
5213 leads to different results from -fbranch-probabilities. */
5214 call = get_call_expr_in (t);
5216 && !(call_expr_flags (call) & ECF_NORETURN))
5219 if (TREE_CODE (t) == ASM_EXPR
5220 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5227 /* Add fake edges to the function exit for any non constant and non
5228 noreturn calls, volatile inline assembly in the bitmap of blocks
5229 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5230 the number of blocks that were split.
5232 The goal is to expose cases in which entering a basic block does
5233 not imply that all subsequent instructions must be executed. */
5236 tree_flow_call_edges_add (sbitmap blocks)
5239 int blocks_split = 0;
5240 int last_bb = last_basic_block;
5241 bool check_last_block = false;
5243 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5247 check_last_block = true;
5249 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5251 /* In the last basic block, before epilogue generation, there will be
5252 a fallthru edge to EXIT. Special care is required if the last insn
5253 of the last basic block is a call because make_edge folds duplicate
5254 edges, which would result in the fallthru edge also being marked
5255 fake, which would result in the fallthru edge being removed by
5256 remove_fake_edges, which would result in an invalid CFG.
5258 Moreover, we can't elide the outgoing fake edge, since the block
5259 profiler needs to take this into account in order to solve the minimal
5260 spanning tree in the case that the call doesn't return.
5262 Handle this by adding a dummy instruction in a new last basic block. */
5263 if (check_last_block)
5265 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5266 block_stmt_iterator bsi = bsi_last (bb);
5268 if (!bsi_end_p (bsi))
5271 if (t && need_fake_edge_p (t))
5275 e = find_edge (bb, EXIT_BLOCK_PTR);
5278 bsi_insert_on_edge (e, build_empty_stmt ());
5279 bsi_commit_edge_inserts ();
5284 /* Now add fake edges to the function exit for any non constant
5285 calls since there is no way that we can determine if they will
5287 for (i = 0; i < last_bb; i++)
5289 basic_block bb = BASIC_BLOCK (i);
5290 block_stmt_iterator bsi;
5291 tree stmt, last_stmt;
5296 if (blocks && !TEST_BIT (blocks, i))
5299 bsi = bsi_last (bb);
5300 if (!bsi_end_p (bsi))
5302 last_stmt = bsi_stmt (bsi);
5305 stmt = bsi_stmt (bsi);
5306 if (need_fake_edge_p (stmt))
5309 /* The handling above of the final block before the
5310 epilogue should be enough to verify that there is
5311 no edge to the exit block in CFG already.
5312 Calling make_edge in such case would cause us to
5313 mark that edge as fake and remove it later. */
5314 #ifdef ENABLE_CHECKING
5315 if (stmt == last_stmt)
5317 e = find_edge (bb, EXIT_BLOCK_PTR);
5318 gcc_assert (e == NULL);
5322 /* Note that the following may create a new basic block
5323 and renumber the existing basic blocks. */
5324 if (stmt != last_stmt)
5326 e = split_block (bb, stmt);
5330 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5334 while (!bsi_end_p (bsi));
5339 verify_flow_info ();
5341 return blocks_split;
5344 /* Purge dead abnormal call edges from basic block BB. */
5347 tree_purge_dead_abnormal_call_edges (basic_block bb)
5349 bool changed = tree_purge_dead_eh_edges (bb);
5351 if (current_function_has_nonlocal_label)
5353 tree stmt = last_stmt (bb);
5357 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5358 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5360 if (e->flags & EDGE_ABNORMAL)
5369 /* See tree_purge_dead_eh_edges below. */
5371 free_dominance_info (CDI_DOMINATORS);
5377 /* Stores all basic blocks dominated by BB to DOM_BBS. */
5380 get_all_dominated_blocks (basic_block bb, VEC (basic_block, heap) **dom_bbs)
5384 VEC_safe_push (basic_block, heap, *dom_bbs, bb);
5385 for (son = first_dom_son (CDI_DOMINATORS, bb);
5387 son = next_dom_son (CDI_DOMINATORS, son))
5388 get_all_dominated_blocks (son, dom_bbs);
5391 /* Removes edge E and all the blocks dominated by it, and updates dominance
5392 information. The IL in E->src needs to be updated separately.
5393 If dominance info is not available, only the edge E is removed.*/
5396 remove_edge_and_dominated_blocks (edge e)
5398 VEC (basic_block, heap) *bbs_to_remove = NULL;
5399 VEC (basic_block, heap) *bbs_to_fix_dom = NULL;
5403 bool none_removed = false;
5405 basic_block bb, dbb;
5408 if (!dom_info_available_p (CDI_DOMINATORS))
5414 /* No updating is needed for edges to exit. */
5415 if (e->dest == EXIT_BLOCK_PTR)
5417 if (cfgcleanup_altered_bbs)
5418 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5423 /* First, we find the basic blocks to remove. If E->dest has a predecessor
5424 that is not dominated by E->dest, then this set is empty. Otherwise,
5425 all the basic blocks dominated by E->dest are removed.
5427 Also, to DF_IDOM we store the immediate dominators of the blocks in
5428 the dominance frontier of E (i.e., of the successors of the
5429 removed blocks, if there are any, and of E->dest otherwise). */
5430 FOR_EACH_EDGE (f, ei, e->dest->preds)
5435 if (!dominated_by_p (CDI_DOMINATORS, f->src, e->dest))
5437 none_removed = true;
5442 df = BITMAP_ALLOC (NULL);
5443 df_idom = BITMAP_ALLOC (NULL);
5446 bitmap_set_bit (df_idom,
5447 get_immediate_dominator (CDI_DOMINATORS, e->dest)->index);
5450 get_all_dominated_blocks (e->dest, &bbs_to_remove);
5451 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5453 FOR_EACH_EDGE (f, ei, bb->succs)
5455 if (f->dest != EXIT_BLOCK_PTR)
5456 bitmap_set_bit (df, f->dest->index);
5459 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5460 bitmap_clear_bit (df, bb->index);
5462 EXECUTE_IF_SET_IN_BITMAP (df, 0, i, bi)
5464 bb = BASIC_BLOCK (i);
5465 bitmap_set_bit (df_idom,
5466 get_immediate_dominator (CDI_DOMINATORS, bb)->index);
5470 if (cfgcleanup_altered_bbs)
5472 /* Record the set of the altered basic blocks. */
5473 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5474 bitmap_ior_into (cfgcleanup_altered_bbs, df);
5477 /* Remove E and the cancelled blocks. */
5482 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5483 delete_basic_block (bb);
5486 /* Update the dominance information. The immediate dominator may change only
5487 for blocks whose immediate dominator belongs to DF_IDOM:
5489 Suppose that idom(X) = Y before removal of E and idom(X) != Y after the
5490 removal. Let Z the arbitrary block such that idom(Z) = Y and
5491 Z dominates X after the removal. Before removal, there exists a path P
5492 from Y to X that avoids Z. Let F be the last edge on P that is
5493 removed, and let W = F->dest. Before removal, idom(W) = Y (since Y
5494 dominates W, and because of P, Z does not dominate W), and W belongs to
5495 the dominance frontier of E. Therefore, Y belongs to DF_IDOM. */
5496 EXECUTE_IF_SET_IN_BITMAP (df_idom, 0, i, bi)
5498 bb = BASIC_BLOCK (i);
5499 for (dbb = first_dom_son (CDI_DOMINATORS, bb);
5501 dbb = next_dom_son (CDI_DOMINATORS, dbb))
5502 VEC_safe_push (basic_block, heap, bbs_to_fix_dom, dbb);
5505 iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true);
5508 BITMAP_FREE (df_idom);
5509 VEC_free (basic_block, heap, bbs_to_remove);
5510 VEC_free (basic_block, heap, bbs_to_fix_dom);
5513 /* Purge dead EH edges from basic block BB. */
5516 tree_purge_dead_eh_edges (basic_block bb)
5518 bool changed = false;
5521 tree stmt = last_stmt (bb);
5523 if (stmt && tree_can_throw_internal (stmt))
5526 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5528 if (e->flags & EDGE_EH)
5530 remove_edge_and_dominated_blocks (e);
5541 tree_purge_all_dead_eh_edges (bitmap blocks)
5543 bool changed = false;
5547 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5549 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5555 /* This function is called whenever a new edge is created or
5559 tree_execute_on_growing_pred (edge e)
5561 basic_block bb = e->dest;
5564 reserve_phi_args_for_new_edge (bb);
5567 /* This function is called immediately before edge E is removed from
5568 the edge vector E->dest->preds. */
5571 tree_execute_on_shrinking_pred (edge e)
5573 if (phi_nodes (e->dest))
5574 remove_phi_args (e);
5577 /*---------------------------------------------------------------------------
5578 Helper functions for Loop versioning
5579 ---------------------------------------------------------------------------*/
5581 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5582 of 'first'. Both of them are dominated by 'new_head' basic block. When
5583 'new_head' was created by 'second's incoming edge it received phi arguments
5584 on the edge by split_edge(). Later, additional edge 'e' was created to
5585 connect 'new_head' and 'first'. Now this routine adds phi args on this
5586 additional edge 'e' that new_head to second edge received as part of edge
5591 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5592 basic_block new_head, edge e)
5595 edge e2 = find_edge (new_head, second);
5597 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5598 edge, we should always have an edge from NEW_HEAD to SECOND. */
5599 gcc_assert (e2 != NULL);
5601 /* Browse all 'second' basic block phi nodes and add phi args to
5602 edge 'e' for 'first' head. PHI args are always in correct order. */
5604 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5606 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5608 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5609 add_phi_arg (phi1, def, e);
5613 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5614 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5615 the destination of the ELSE part. */
5617 tree_lv_add_condition_to_bb (basic_block first_head ATTRIBUTE_UNUSED,
5618 basic_block second_head ATTRIBUTE_UNUSED,
5619 basic_block cond_bb, void *cond_e)
5621 block_stmt_iterator bsi;
5622 tree new_cond_expr = NULL_TREE;
5623 tree cond_expr = (tree) cond_e;
5626 /* Build new conditional expr */
5627 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr,
5628 NULL_TREE, NULL_TREE);
5630 /* Add new cond in cond_bb. */
5631 bsi = bsi_start (cond_bb);
5632 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5633 /* Adjust edges appropriately to connect new head with first head
5634 as well as second head. */
5635 e0 = single_succ_edge (cond_bb);
5636 e0->flags &= ~EDGE_FALLTHRU;
5637 e0->flags |= EDGE_FALSE_VALUE;
5640 struct cfg_hooks tree_cfg_hooks = {
5642 tree_verify_flow_info,
5643 tree_dump_bb, /* dump_bb */
5644 create_bb, /* create_basic_block */
5645 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5646 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5647 tree_can_remove_branch_p, /* can_remove_branch_p */
5648 remove_bb, /* delete_basic_block */
5649 tree_split_block, /* split_block */
5650 tree_move_block_after, /* move_block_after */
5651 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5652 tree_merge_blocks, /* merge_blocks */
5653 tree_predict_edge, /* predict_edge */
5654 tree_predicted_by_p, /* predicted_by_p */
5655 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5656 tree_duplicate_bb, /* duplicate_block */
5657 tree_split_edge, /* split_edge */
5658 tree_make_forwarder_block, /* make_forward_block */
5659 NULL, /* tidy_fallthru_edge */
5660 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5661 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5662 tree_flow_call_edges_add, /* flow_call_edges_add */
5663 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5664 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5665 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5666 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5667 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5668 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5669 flush_pending_stmts /* flush_pending_stmts */
5673 /* Split all critical edges. */
5676 split_critical_edges (void)
5682 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5683 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5684 mappings around the calls to split_edge. */
5685 start_recording_case_labels ();
5688 FOR_EACH_EDGE (e, ei, bb->succs)
5689 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5694 end_recording_case_labels ();
5698 struct tree_opt_pass pass_split_crit_edges =
5700 "crited", /* name */
5702 split_critical_edges, /* execute */
5705 0, /* static_pass_number */
5706 TV_TREE_SPLIT_EDGES, /* tv_id */
5707 PROP_cfg, /* properties required */
5708 PROP_no_crit_edges, /* properties_provided */
5709 0, /* properties_destroyed */
5710 0, /* todo_flags_start */
5711 TODO_dump_func, /* todo_flags_finish */
5716 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5717 a temporary, make sure and register it to be renamed if necessary,
5718 and finally return the temporary. Put the statements to compute
5719 EXP before the current statement in BSI. */
5722 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5724 tree t, new_stmt, orig_stmt;
5726 if (is_gimple_val (exp))
5729 t = make_rename_temp (type, NULL);
5730 new_stmt = build_gimple_modify_stmt (t, exp);
5732 orig_stmt = bsi_stmt (*bsi);
5733 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5734 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5736 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5737 if (gimple_in_ssa_p (cfun))
5738 mark_symbols_for_renaming (new_stmt);
5743 /* Build a ternary operation and gimplify it. Emit code before BSI.
5744 Return the gimple_val holding the result. */
5747 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5748 tree type, tree a, tree b, tree c)
5752 ret = fold_build3 (code, type, a, b, c);
5755 return gimplify_val (bsi, type, ret);
5758 /* Build a binary operation and gimplify it. Emit code before BSI.
5759 Return the gimple_val holding the result. */
5762 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5763 tree type, tree a, tree b)
5767 ret = fold_build2 (code, type, a, b);
5770 return gimplify_val (bsi, type, ret);
5773 /* Build a unary operation and gimplify it. Emit code before BSI.
5774 Return the gimple_val holding the result. */
5777 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5782 ret = fold_build1 (code, type, a);
5785 return gimplify_val (bsi, type, ret);
5790 /* Emit return warnings. */
5793 execute_warn_function_return (void)
5795 #ifdef USE_MAPPED_LOCATION
5796 source_location location;
5804 /* If we have a path to EXIT, then we do return. */
5805 if (TREE_THIS_VOLATILE (cfun->decl)
5806 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5808 #ifdef USE_MAPPED_LOCATION
5809 location = UNKNOWN_LOCATION;
5813 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5815 last = last_stmt (e->src);
5816 if (TREE_CODE (last) == RETURN_EXPR
5817 #ifdef USE_MAPPED_LOCATION
5818 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5820 && (locus = EXPR_LOCUS (last)) != NULL)
5824 #ifdef USE_MAPPED_LOCATION
5825 if (location == UNKNOWN_LOCATION)
5826 location = cfun->function_end_locus;
5827 warning (0, "%H%<noreturn%> function does return", &location);
5830 locus = &cfun->function_end_locus;
5831 warning (0, "%H%<noreturn%> function does return", locus);
5835 /* If we see "return;" in some basic block, then we do reach the end
5836 without returning a value. */
5837 else if (warn_return_type
5838 && !TREE_NO_WARNING (cfun->decl)
5839 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5840 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5842 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5844 tree last = last_stmt (e->src);
5845 if (TREE_CODE (last) == RETURN_EXPR
5846 && TREE_OPERAND (last, 0) == NULL
5847 && !TREE_NO_WARNING (last))
5849 #ifdef USE_MAPPED_LOCATION
5850 location = EXPR_LOCATION (last);
5851 if (location == UNKNOWN_LOCATION)
5852 location = cfun->function_end_locus;
5853 warning (0, "%Hcontrol reaches end of non-void function", &location);
5855 locus = EXPR_LOCUS (last);
5857 locus = &cfun->function_end_locus;
5858 warning (0, "%Hcontrol reaches end of non-void function", locus);
5860 TREE_NO_WARNING (cfun->decl) = 1;
5869 /* Given a basic block B which ends with a conditional and has
5870 precisely two successors, determine which of the edges is taken if
5871 the conditional is true and which is taken if the conditional is
5872 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5875 extract_true_false_edges_from_block (basic_block b,
5879 edge e = EDGE_SUCC (b, 0);
5881 if (e->flags & EDGE_TRUE_VALUE)
5884 *false_edge = EDGE_SUCC (b, 1);
5889 *true_edge = EDGE_SUCC (b, 1);
5893 struct tree_opt_pass pass_warn_function_return =
5897 execute_warn_function_return, /* execute */
5900 0, /* static_pass_number */
5902 PROP_cfg, /* properties_required */
5903 0, /* properties_provided */
5904 0, /* properties_destroyed */
5905 0, /* todo_flags_start */
5906 0, /* todo_flags_finish */
5910 /* Emit noreturn warnings. */
5913 execute_warn_function_noreturn (void)
5915 if (warn_missing_noreturn
5916 && !TREE_THIS_VOLATILE (cfun->decl)
5917 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5918 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5919 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5920 "for attribute %<noreturn%>",
5925 struct tree_opt_pass pass_warn_function_noreturn =
5929 execute_warn_function_noreturn, /* execute */
5932 0, /* static_pass_number */
5934 PROP_cfg, /* properties_required */
5935 0, /* properties_provided */
5936 0, /* properties_destroyed */
5937 0, /* todo_flags_start */
5938 0, /* todo_flags_finish */