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 2, 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 COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
47 #include "tree-ssa-propagate.h"
48 #include "value-prof.h"
49 #include "pointer-set.h"
51 /* This file contains functions for building the Control Flow Graph (CFG)
52 for a function tree. */
54 /* Local declarations. */
56 /* Initial capacity for the basic block array. */
57 static const int initial_cfg_capacity = 20;
59 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
60 which use a particular edge. The CASE_LABEL_EXPRs are chained together
61 via their TREE_CHAIN field, which we clear after we're done with the
62 hash table to prevent problems with duplication of SWITCH_EXPRs.
64 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
65 update the case vector in response to edge redirections.
67 Right now this table is set up and torn down at key points in the
68 compilation process. It would be nice if we could make the table
69 more persistent. The key is getting notification of changes to
70 the CFG (particularly edge removal, creation and redirection). */
72 static struct pointer_map_t *edge_to_cases;
77 long num_merged_labels;
80 static struct cfg_stats_d cfg_stats;
82 /* Nonzero if we found a computed goto while building basic blocks. */
83 static bool found_computed_goto;
85 /* Basic blocks and flowgraphs. */
86 static basic_block create_bb (void *, void *, basic_block);
87 static void make_blocks (tree);
88 static void factor_computed_gotos (void);
91 static void make_edges (void);
92 static void make_cond_expr_edges (basic_block);
93 static void make_switch_expr_edges (basic_block);
94 static void make_goto_expr_edges (basic_block);
95 static edge tree_redirect_edge_and_branch (edge, basic_block);
96 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
97 static unsigned int split_critical_edges (void);
99 /* Various helpers. */
100 static inline bool stmt_starts_bb_p (tree, tree);
101 static int tree_verify_flow_info (void);
102 static void tree_make_forwarder_block (edge);
103 static void tree_cfg2vcg (FILE *);
104 static inline void change_bb_for_stmt (tree t, basic_block bb);
106 /* Flowgraph optimization and cleanup. */
107 static void tree_merge_blocks (basic_block, basic_block);
108 static bool tree_can_merge_blocks_p (basic_block, basic_block);
109 static void remove_bb (basic_block);
110 static edge find_taken_edge_computed_goto (basic_block, tree);
111 static edge find_taken_edge_cond_expr (basic_block, tree);
112 static edge find_taken_edge_switch_expr (basic_block, tree);
113 static tree find_case_label_for_value (tree, tree);
116 init_empty_tree_cfg (void)
118 /* Initialize the basic block array. */
120 profile_status = PROFILE_ABSENT;
121 n_basic_blocks = NUM_FIXED_BLOCKS;
122 last_basic_block = NUM_FIXED_BLOCKS;
123 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
124 VEC_safe_grow_cleared (basic_block, gc, basic_block_info,
125 initial_cfg_capacity);
127 /* Build a mapping of labels to their associated blocks. */
128 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
129 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
130 initial_cfg_capacity);
132 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
133 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
134 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
135 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
138 /*---------------------------------------------------------------------------
140 ---------------------------------------------------------------------------*/
142 /* Entry point to the CFG builder for trees. TP points to the list of
143 statements to be added to the flowgraph. */
146 build_tree_cfg (tree *tp)
148 /* Register specific tree functions. */
149 tree_register_cfg_hooks ();
151 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
153 init_empty_tree_cfg ();
155 found_computed_goto = 0;
158 /* Computed gotos are hell to deal with, especially if there are
159 lots of them with a large number of destinations. So we factor
160 them to a common computed goto location before we build the
161 edge list. After we convert back to normal form, we will un-factor
162 the computed gotos since factoring introduces an unwanted jump. */
163 if (found_computed_goto)
164 factor_computed_gotos ();
166 /* Make sure there is always at least one block, even if it's empty. */
167 if (n_basic_blocks == NUM_FIXED_BLOCKS)
168 create_empty_bb (ENTRY_BLOCK_PTR);
170 /* Adjust the size of the array. */
171 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
172 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, n_basic_blocks);
174 /* To speed up statement iterator walks, we first purge dead labels. */
175 cleanup_dead_labels ();
177 /* Group case nodes to reduce the number of edges.
178 We do this after cleaning up dead labels because otherwise we miss
179 a lot of obvious case merging opportunities. */
180 group_case_labels ();
182 /* Create the edges of the flowgraph. */
184 cleanup_dead_labels ();
186 /* Debugging dumps. */
188 /* Write the flowgraph to a VCG file. */
190 int local_dump_flags;
191 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
194 tree_cfg2vcg (vcg_file);
195 dump_end (TDI_vcg, vcg_file);
199 #ifdef ENABLE_CHECKING
203 /* Dump a textual representation of the flowgraph. */
205 dump_tree_cfg (dump_file, dump_flags);
209 execute_build_cfg (void)
211 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
215 struct tree_opt_pass pass_build_cfg =
219 execute_build_cfg, /* execute */
222 0, /* static_pass_number */
223 TV_TREE_CFG, /* tv_id */
224 PROP_gimple_leh, /* properties_required */
225 PROP_cfg, /* properties_provided */
226 0, /* properties_destroyed */
227 0, /* todo_flags_start */
228 TODO_verify_stmts | TODO_cleanup_cfg, /* todo_flags_finish */
232 /* Search the CFG for any computed gotos. If found, factor them to a
233 common computed goto site. Also record the location of that site so
234 that we can un-factor the gotos after we have converted back to
238 factor_computed_gotos (void)
241 tree factored_label_decl = NULL;
243 tree factored_computed_goto_label = NULL;
244 tree factored_computed_goto = NULL;
246 /* We know there are one or more computed gotos in this function.
247 Examine the last statement in each basic block to see if the block
248 ends with a computed goto. */
252 block_stmt_iterator bsi = bsi_last (bb);
257 last = bsi_stmt (bsi);
259 /* Ignore the computed goto we create when we factor the original
261 if (last == factored_computed_goto)
264 /* If the last statement is a computed goto, factor it. */
265 if (computed_goto_p (last))
269 /* The first time we find a computed goto we need to create
270 the factored goto block and the variable each original
271 computed goto will use for their goto destination. */
272 if (! factored_computed_goto)
274 basic_block new_bb = create_empty_bb (bb);
275 block_stmt_iterator new_bsi = bsi_start (new_bb);
277 /* Create the destination of the factored goto. Each original
278 computed goto will put its desired destination into this
279 variable and jump to the label we create immediately
281 var = create_tmp_var (ptr_type_node, "gotovar");
283 /* Build a label for the new block which will contain the
284 factored computed goto. */
285 factored_label_decl = create_artificial_label ();
286 factored_computed_goto_label
287 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
288 bsi_insert_after (&new_bsi, factored_computed_goto_label,
291 /* Build our new computed goto. */
292 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
293 bsi_insert_after (&new_bsi, factored_computed_goto,
297 /* Copy the original computed goto's destination into VAR. */
298 assignment = build_gimple_modify_stmt (var,
299 GOTO_DESTINATION (last));
300 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
302 /* And re-vector the computed goto to the new destination. */
303 GOTO_DESTINATION (last) = factored_label_decl;
309 /* Build a flowgraph for the statement_list STMT_LIST. */
312 make_blocks (tree stmt_list)
314 tree_stmt_iterator i = tsi_start (stmt_list);
316 bool start_new_block = true;
317 bool first_stmt_of_list = true;
318 basic_block bb = ENTRY_BLOCK_PTR;
320 while (!tsi_end_p (i))
327 /* If the statement starts a new basic block or if we have determined
328 in a previous pass that we need to create a new block for STMT, do
330 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
332 if (!first_stmt_of_list)
333 stmt_list = tsi_split_statement_list_before (&i);
334 bb = create_basic_block (stmt_list, NULL, bb);
335 start_new_block = false;
338 /* Now add STMT to BB and create the subgraphs for special statement
340 set_bb_for_stmt (stmt, bb);
342 if (computed_goto_p (stmt))
343 found_computed_goto = true;
345 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
347 if (stmt_ends_bb_p (stmt))
348 start_new_block = true;
351 first_stmt_of_list = false;
356 /* Create and return a new empty basic block after bb AFTER. */
359 create_bb (void *h, void *e, basic_block after)
365 /* Create and initialize a new basic block. Since alloc_block uses
366 ggc_alloc_cleared to allocate a basic block, we do not have to
367 clear the newly allocated basic block here. */
370 bb->index = last_basic_block;
372 bb->il.tree = GGC_CNEW (struct tree_bb_info);
373 set_bb_stmt_list (bb, h ? (tree) h : alloc_stmt_list ());
375 /* Add the new block to the linked list of blocks. */
376 link_block (bb, after);
378 /* Grow the basic block array if needed. */
379 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
381 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
382 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
385 /* Add the newly created block to the array. */
386 SET_BASIC_BLOCK (last_basic_block, bb);
395 /*---------------------------------------------------------------------------
397 ---------------------------------------------------------------------------*/
399 /* Fold COND_EXPR_COND of each COND_EXPR. */
402 fold_cond_expr_cond (void)
408 tree stmt = last_stmt (bb);
411 && TREE_CODE (stmt) == COND_EXPR)
416 fold_defer_overflow_warnings ();
417 cond = fold (COND_EXPR_COND (stmt));
418 zerop = integer_zerop (cond);
419 onep = integer_onep (cond);
420 fold_undefer_overflow_warnings (((zerop || onep)
421 && !TREE_NO_WARNING (stmt)),
423 WARN_STRICT_OVERFLOW_CONDITIONAL);
425 COND_EXPR_COND (stmt) = boolean_false_node;
427 COND_EXPR_COND (stmt) = boolean_true_node;
432 /* Join all the blocks in the flowgraph. */
438 struct omp_region *cur_region = NULL;
440 /* Create an edge from entry to the first block with executable
442 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
444 /* Traverse the basic block array placing edges. */
447 tree last = last_stmt (bb);
452 enum tree_code code = TREE_CODE (last);
456 make_goto_expr_edges (bb);
460 make_edge (bb, EXIT_BLOCK_PTR, 0);
464 make_cond_expr_edges (bb);
468 make_switch_expr_edges (bb);
472 make_eh_edges (last);
477 /* If this function receives a nonlocal goto, then we need to
478 make edges from this call site to all the nonlocal goto
480 if (tree_can_make_abnormal_goto (last))
481 make_abnormal_goto_edges (bb, true);
483 /* If this statement has reachable exception handlers, then
484 create abnormal edges to them. */
485 make_eh_edges (last);
487 /* Some calls are known not to return. */
488 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
494 case GIMPLE_MODIFY_STMT:
495 if (is_ctrl_altering_stmt (last))
497 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
498 the CALL_EXPR may have an abnormal edge. Search the RHS
499 for this case and create any required edges. */
500 if (tree_can_make_abnormal_goto (last))
501 make_abnormal_goto_edges (bb, true);
503 make_eh_edges (last);
515 cur_region = new_omp_region (bb, code, cur_region);
520 cur_region = new_omp_region (bb, code, cur_region);
525 /* In the case of an OMP_SECTION, the edge will go somewhere
526 other than the next block. This will be created later. */
527 cur_region->exit = bb;
528 fallthru = cur_region->type != OMP_SECTION;
529 cur_region = cur_region->outer;
533 cur_region->cont = bb;
534 switch (cur_region->type)
537 /* ??? Technically there should be a some sort of loopback
538 edge here, but it goes to a block that doesn't exist yet,
539 and without it, updating the ssa form would be a real
540 bear. Fortunately, we don't yet do ssa before expanding
545 /* Wire up the edges into and out of the nested sections. */
546 /* ??? Similarly wrt loopback. */
548 struct omp_region *i;
549 for (i = cur_region->inner; i ; i = i->next)
551 gcc_assert (i->type == OMP_SECTION);
552 make_edge (cur_region->entry, i->entry, 0);
553 make_edge (i->exit, bb, EDGE_FALLTHRU);
565 gcc_assert (!stmt_ends_bb_p (last));
573 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
579 /* Fold COND_EXPR_COND of each COND_EXPR. */
580 fold_cond_expr_cond ();
584 /* Create the edges for a COND_EXPR starting at block BB.
585 At this point, both clauses must contain only simple gotos. */
588 make_cond_expr_edges (basic_block bb)
590 tree entry = last_stmt (bb);
591 basic_block then_bb, else_bb;
592 tree then_label, else_label;
596 gcc_assert (TREE_CODE (entry) == COND_EXPR);
598 /* Entry basic blocks for each component. */
599 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
600 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
601 then_bb = label_to_block (then_label);
602 else_bb = label_to_block (else_label);
604 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
605 #ifdef USE_MAPPED_LOCATION
606 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
608 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
610 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
613 #ifdef USE_MAPPED_LOCATION
614 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
616 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
620 /* We do not need the gotos anymore. */
621 COND_EXPR_THEN (entry) = NULL_TREE;
622 COND_EXPR_ELSE (entry) = NULL_TREE;
626 /* Called for each element in the hash table (P) as we delete the
627 edge to cases hash table.
629 Clear all the TREE_CHAINs to prevent problems with copying of
630 SWITCH_EXPRs and structure sharing rules, then free the hash table
634 edge_to_cases_cleanup (void *key ATTRIBUTE_UNUSED, void **value,
635 void *data ATTRIBUTE_UNUSED)
639 for (t = (tree) *value; t; t = next)
641 next = TREE_CHAIN (t);
642 TREE_CHAIN (t) = NULL;
649 /* Start recording information mapping edges to case labels. */
652 start_recording_case_labels (void)
654 gcc_assert (edge_to_cases == NULL);
655 edge_to_cases = pointer_map_create ();
658 /* Return nonzero if we are recording information for case labels. */
661 recording_case_labels_p (void)
663 return (edge_to_cases != NULL);
666 /* Stop recording information mapping edges to case labels and
667 remove any information we have recorded. */
669 end_recording_case_labels (void)
671 pointer_map_traverse (edge_to_cases, edge_to_cases_cleanup, NULL);
672 pointer_map_destroy (edge_to_cases);
673 edge_to_cases = NULL;
676 /* If we are inside a {start,end}_recording_cases block, then return
677 a chain of CASE_LABEL_EXPRs from T which reference E.
679 Otherwise return NULL. */
682 get_cases_for_edge (edge e, tree t)
688 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
689 chains available. Return NULL so the caller can detect this case. */
690 if (!recording_case_labels_p ())
693 slot = pointer_map_contains (edge_to_cases, e);
697 /* If we did not find E in the hash table, then this must be the first
698 time we have been queried for information about E & T. Add all the
699 elements from T to the hash table then perform the query again. */
701 vec = SWITCH_LABELS (t);
702 n = TREE_VEC_LENGTH (vec);
703 for (i = 0; i < n; i++)
705 tree elt = TREE_VEC_ELT (vec, i);
706 tree lab = CASE_LABEL (elt);
707 basic_block label_bb = label_to_block (lab);
708 edge this_edge = find_edge (e->src, label_bb);
710 /* Add it to the chain of CASE_LABEL_EXPRs referencing E, or create
712 slot = pointer_map_insert (edge_to_cases, this_edge);
713 TREE_CHAIN (elt) = (tree) *slot;
717 return (tree) *pointer_map_contains (edge_to_cases, e);
720 /* Create the edges for a SWITCH_EXPR starting at block BB.
721 At this point, the switch body has been lowered and the
722 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
725 make_switch_expr_edges (basic_block bb)
727 tree entry = last_stmt (bb);
731 vec = SWITCH_LABELS (entry);
732 n = TREE_VEC_LENGTH (vec);
734 for (i = 0; i < n; ++i)
736 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
737 basic_block label_bb = label_to_block (lab);
738 make_edge (bb, label_bb, 0);
743 /* Return the basic block holding label DEST. */
746 label_to_block_fn (struct function *ifun, tree dest)
748 int uid = LABEL_DECL_UID (dest);
750 /* We would die hard when faced by an undefined label. Emit a label to
751 the very first basic block. This will hopefully make even the dataflow
752 and undefined variable warnings quite right. */
753 if ((errorcount || sorrycount) && uid < 0)
755 block_stmt_iterator bsi =
756 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
759 stmt = build1 (LABEL_EXPR, void_type_node, dest);
760 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
761 uid = LABEL_DECL_UID (dest);
763 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
764 <= (unsigned int) uid)
766 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
769 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
770 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
773 make_abnormal_goto_edges (basic_block bb, bool for_call)
775 basic_block target_bb;
776 block_stmt_iterator bsi;
778 FOR_EACH_BB (target_bb)
779 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
781 tree target = bsi_stmt (bsi);
783 if (TREE_CODE (target) != LABEL_EXPR)
786 target = LABEL_EXPR_LABEL (target);
788 /* Make an edge to every label block that has been marked as a
789 potential target for a computed goto or a non-local goto. */
790 if ((FORCED_LABEL (target) && !for_call)
791 || (DECL_NONLOCAL (target) && for_call))
793 make_edge (bb, target_bb, EDGE_ABNORMAL);
799 /* Create edges for a goto statement at block BB. */
802 make_goto_expr_edges (basic_block bb)
804 block_stmt_iterator last = bsi_last (bb);
805 tree goto_t = bsi_stmt (last);
807 /* A simple GOTO creates normal edges. */
808 if (simple_goto_p (goto_t))
810 tree dest = GOTO_DESTINATION (goto_t);
811 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
812 #ifdef USE_MAPPED_LOCATION
813 e->goto_locus = EXPR_LOCATION (goto_t);
815 e->goto_locus = EXPR_LOCUS (goto_t);
817 bsi_remove (&last, true);
821 /* A computed GOTO creates abnormal edges. */
822 make_abnormal_goto_edges (bb, false);
826 /*---------------------------------------------------------------------------
828 ---------------------------------------------------------------------------*/
830 /* Cleanup useless labels in basic blocks. This is something we wish
831 to do early because it allows us to group case labels before creating
832 the edges for the CFG, and it speeds up block statement iterators in
834 We rerun this pass after CFG is created, to get rid of the labels that
835 are no longer referenced. After then we do not run it any more, since
836 (almost) no new labels should be created. */
838 /* A map from basic block index to the leading label of that block. */
839 static struct label_record
844 /* True if the label is referenced from somewhere. */
848 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
850 update_eh_label (struct eh_region *region)
852 tree old_label = get_eh_region_tree_label (region);
856 basic_block bb = label_to_block (old_label);
858 /* ??? After optimizing, there may be EH regions with labels
859 that have already been removed from the function body, so
860 there is no basic block for them. */
864 new_label = label_for_bb[bb->index].label;
865 label_for_bb[bb->index].used = true;
866 set_eh_region_tree_label (region, new_label);
870 /* Given LABEL return the first label in the same basic block. */
872 main_block_label (tree label)
874 basic_block bb = label_to_block (label);
875 tree main_label = label_for_bb[bb->index].label;
877 /* label_to_block possibly inserted undefined label into the chain. */
880 label_for_bb[bb->index].label = label;
884 label_for_bb[bb->index].used = true;
888 /* Cleanup redundant labels. This is a three-step process:
889 1) Find the leading label for each block.
890 2) Redirect all references to labels to the leading labels.
891 3) Cleanup all useless labels. */
894 cleanup_dead_labels (void)
897 label_for_bb = XCNEWVEC (struct label_record, last_basic_block);
899 /* Find a suitable label for each block. We use the first user-defined
900 label if there is one, or otherwise just the first label we see. */
903 block_stmt_iterator i;
905 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
907 tree label, stmt = bsi_stmt (i);
909 if (TREE_CODE (stmt) != LABEL_EXPR)
912 label = LABEL_EXPR_LABEL (stmt);
914 /* If we have not yet seen a label for the current block,
915 remember this one and see if there are more labels. */
916 if (!label_for_bb[bb->index].label)
918 label_for_bb[bb->index].label = label;
922 /* If we did see a label for the current block already, but it
923 is an artificially created label, replace it if the current
924 label is a user defined label. */
925 if (!DECL_ARTIFICIAL (label)
926 && DECL_ARTIFICIAL (label_for_bb[bb->index].label))
928 label_for_bb[bb->index].label = label;
934 /* Now redirect all jumps/branches to the selected label.
935 First do so for each block ending in a control statement. */
938 tree stmt = last_stmt (bb);
942 switch (TREE_CODE (stmt))
946 tree true_branch, false_branch;
948 true_branch = COND_EXPR_THEN (stmt);
949 false_branch = COND_EXPR_ELSE (stmt);
952 GOTO_DESTINATION (true_branch)
953 = main_block_label (GOTO_DESTINATION (true_branch));
955 GOTO_DESTINATION (false_branch)
956 = main_block_label (GOTO_DESTINATION (false_branch));
964 tree vec = SWITCH_LABELS (stmt);
965 size_t n = TREE_VEC_LENGTH (vec);
967 /* Replace all destination labels. */
968 for (i = 0; i < n; ++i)
970 tree elt = TREE_VEC_ELT (vec, i);
971 tree label = main_block_label (CASE_LABEL (elt));
972 CASE_LABEL (elt) = label;
977 /* We have to handle GOTO_EXPRs until they're removed, and we don't
978 remove them until after we've created the CFG edges. */
980 if (! computed_goto_p (stmt))
982 GOTO_DESTINATION (stmt)
983 = main_block_label (GOTO_DESTINATION (stmt));
992 for_each_eh_region (update_eh_label);
994 /* Finally, purge dead labels. All user-defined labels and labels that
995 can be the target of non-local gotos and labels which have their
996 address taken are preserved. */
999 block_stmt_iterator i;
1000 tree label_for_this_bb = label_for_bb[bb->index].label;
1002 if (!label_for_this_bb)
1005 /* If the main label of the block is unused, we may still remove it. */
1006 if (!label_for_bb[bb->index].used)
1007 label_for_this_bb = NULL;
1009 for (i = bsi_start (bb); !bsi_end_p (i); )
1011 tree label, stmt = bsi_stmt (i);
1013 if (TREE_CODE (stmt) != LABEL_EXPR)
1016 label = LABEL_EXPR_LABEL (stmt);
1018 if (label == label_for_this_bb
1019 || ! DECL_ARTIFICIAL (label)
1020 || DECL_NONLOCAL (label)
1021 || FORCED_LABEL (label))
1024 bsi_remove (&i, true);
1028 free (label_for_bb);
1031 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1032 and scan the sorted vector of cases. Combine the ones jumping to the
1034 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1037 group_case_labels (void)
1043 tree stmt = last_stmt (bb);
1044 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1046 tree labels = SWITCH_LABELS (stmt);
1047 int old_size = TREE_VEC_LENGTH (labels);
1048 int i, j, new_size = old_size;
1049 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1052 /* The default label is always the last case in a switch
1053 statement after gimplification. */
1054 default_label = CASE_LABEL (default_case);
1056 /* Look for possible opportunities to merge cases.
1057 Ignore the last element of the label vector because it
1058 must be the default case. */
1060 while (i < old_size - 1)
1062 tree base_case, base_label, base_high;
1063 base_case = TREE_VEC_ELT (labels, i);
1065 gcc_assert (base_case);
1066 base_label = CASE_LABEL (base_case);
1068 /* Discard cases that have the same destination as the
1070 if (base_label == default_label)
1072 TREE_VEC_ELT (labels, i) = NULL_TREE;
1078 base_high = CASE_HIGH (base_case) ?
1079 CASE_HIGH (base_case) : CASE_LOW (base_case);
1081 /* Try to merge case labels. Break out when we reach the end
1082 of the label vector or when we cannot merge the next case
1083 label with the current one. */
1084 while (i < old_size - 1)
1086 tree merge_case = TREE_VEC_ELT (labels, i);
1087 tree merge_label = CASE_LABEL (merge_case);
1088 tree t = int_const_binop (PLUS_EXPR, base_high,
1089 integer_one_node, 1);
1091 /* Merge the cases if they jump to the same place,
1092 and their ranges are consecutive. */
1093 if (merge_label == base_label
1094 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1096 base_high = CASE_HIGH (merge_case) ?
1097 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1098 CASE_HIGH (base_case) = base_high;
1099 TREE_VEC_ELT (labels, i) = NULL_TREE;
1108 /* Compress the case labels in the label vector, and adjust the
1109 length of the vector. */
1110 for (i = 0, j = 0; i < new_size; i++)
1112 while (! TREE_VEC_ELT (labels, j))
1114 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1116 TREE_VEC_LENGTH (labels) = new_size;
1121 /* Checks whether we can merge block B into block A. */
1124 tree_can_merge_blocks_p (basic_block a, basic_block b)
1127 block_stmt_iterator bsi;
1130 if (!single_succ_p (a))
1133 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1136 if (single_succ (a) != b)
1139 if (!single_pred_p (b))
1142 if (b == EXIT_BLOCK_PTR)
1145 /* If A ends by a statement causing exceptions or something similar, we
1146 cannot merge the blocks. */
1147 stmt = last_stmt (a);
1148 if (stmt && stmt_ends_bb_p (stmt))
1151 /* Do not allow a block with only a non-local label to be merged. */
1152 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1153 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1156 /* It must be possible to eliminate all phi nodes in B. If ssa form
1157 is not up-to-date, we cannot eliminate any phis; however, if only
1158 some symbols as whole are marked for renaming, this is not a problem,
1159 as phi nodes for those symbols are irrelevant in updating anyway. */
1160 phi = phi_nodes (b);
1163 if (name_mappings_registered_p ())
1166 for (; phi; phi = PHI_CHAIN (phi))
1167 if (!is_gimple_reg (PHI_RESULT (phi))
1168 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1172 /* Do not remove user labels. */
1173 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1175 stmt = bsi_stmt (bsi);
1176 if (TREE_CODE (stmt) != LABEL_EXPR)
1178 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1182 /* Protect the loop latches. */
1184 && b->loop_father->latch == b)
1190 /* Replaces all uses of NAME by VAL. */
1193 replace_uses_by (tree name, tree val)
1195 imm_use_iterator imm_iter;
1200 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1202 if (TREE_CODE (stmt) != PHI_NODE)
1203 push_stmt_changes (&stmt);
1205 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1207 replace_exp (use, val);
1209 if (TREE_CODE (stmt) == PHI_NODE)
1211 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1212 if (e->flags & EDGE_ABNORMAL)
1214 /* This can only occur for virtual operands, since
1215 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1216 would prevent replacement. */
1217 gcc_assert (!is_gimple_reg (name));
1218 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1223 if (TREE_CODE (stmt) != PHI_NODE)
1227 fold_stmt_inplace (stmt);
1228 if (cfgcleanup_altered_bbs)
1229 bitmap_set_bit (cfgcleanup_altered_bbs, bb_for_stmt (stmt)->index);
1231 /* FIXME. This should go in pop_stmt_changes. */
1232 rhs = get_rhs (stmt);
1233 if (TREE_CODE (rhs) == ADDR_EXPR)
1234 recompute_tree_invariant_for_addr_expr (rhs);
1236 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1238 pop_stmt_changes (&stmt);
1242 gcc_assert (has_zero_uses (name));
1244 /* Also update the trees stored in loop structures. */
1250 FOR_EACH_LOOP (li, loop, 0)
1252 substitute_in_loop_info (loop, name, val);
1257 /* Merge block B into block A. */
1260 tree_merge_blocks (basic_block a, basic_block b)
1262 block_stmt_iterator bsi;
1263 tree_stmt_iterator last;
1267 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1269 /* Remove all single-valued PHI nodes from block B of the form
1270 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1272 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1274 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1276 bool may_replace_uses = may_propagate_copy (def, use);
1278 /* In case we have loops to care about, do not propagate arguments of
1279 loop closed ssa phi nodes. */
1281 && is_gimple_reg (def)
1282 && TREE_CODE (use) == SSA_NAME
1283 && a->loop_father != b->loop_father)
1284 may_replace_uses = false;
1286 if (!may_replace_uses)
1288 gcc_assert (is_gimple_reg (def));
1290 /* Note that just emitting the copies is fine -- there is no problem
1291 with ordering of phi nodes. This is because A is the single
1292 predecessor of B, therefore results of the phi nodes cannot
1293 appear as arguments of the phi nodes. */
1294 copy = build_gimple_modify_stmt (def, use);
1295 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1296 SSA_NAME_DEF_STMT (def) = copy;
1297 remove_phi_node (phi, NULL, false);
1301 replace_uses_by (def, use);
1302 remove_phi_node (phi, NULL, true);
1306 /* Ensure that B follows A. */
1307 move_block_after (b, a);
1309 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1310 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1312 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1313 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1315 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1317 tree label = bsi_stmt (bsi);
1319 bsi_remove (&bsi, false);
1320 /* Now that we can thread computed gotos, we might have
1321 a situation where we have a forced label in block B
1322 However, the label at the start of block B might still be
1323 used in other ways (think about the runtime checking for
1324 Fortran assigned gotos). So we can not just delete the
1325 label. Instead we move the label to the start of block A. */
1326 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1328 block_stmt_iterator dest_bsi = bsi_start (a);
1329 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1334 change_bb_for_stmt (bsi_stmt (bsi), a);
1339 /* Merge the chains. */
1340 last = tsi_last (bb_stmt_list (a));
1341 tsi_link_after (&last, bb_stmt_list (b), TSI_NEW_STMT);
1342 set_bb_stmt_list (b, NULL_TREE);
1344 if (cfgcleanup_altered_bbs)
1345 bitmap_set_bit (cfgcleanup_altered_bbs, a->index);
1349 /* Return the one of two successors of BB that is not reachable by a
1350 reached by a complex edge, if there is one. Else, return BB. We use
1351 this in optimizations that use post-dominators for their heuristics,
1352 to catch the cases in C++ where function calls are involved. */
1355 single_noncomplex_succ (basic_block bb)
1358 if (EDGE_COUNT (bb->succs) != 2)
1361 e0 = EDGE_SUCC (bb, 0);
1362 e1 = EDGE_SUCC (bb, 1);
1363 if (e0->flags & EDGE_COMPLEX)
1365 if (e1->flags & EDGE_COMPLEX)
1372 /* Walk the function tree removing unnecessary statements.
1374 * Empty statement nodes are removed
1376 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1378 * Unnecessary COND_EXPRs are removed
1380 * Some unnecessary BIND_EXPRs are removed
1382 Clearly more work could be done. The trick is doing the analysis
1383 and removal fast enough to be a net improvement in compile times.
1385 Note that when we remove a control structure such as a COND_EXPR
1386 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1387 to ensure we eliminate all the useless code. */
1398 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1401 remove_useless_stmts_warn_notreached (tree stmt)
1403 if (EXPR_HAS_LOCATION (stmt))
1405 location_t loc = EXPR_LOCATION (stmt);
1406 if (LOCATION_LINE (loc) > 0)
1408 warning (0, "%Hwill never be executed", &loc);
1413 switch (TREE_CODE (stmt))
1415 case STATEMENT_LIST:
1417 tree_stmt_iterator i;
1418 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1419 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1425 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1427 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1429 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1433 case TRY_FINALLY_EXPR:
1434 case TRY_CATCH_EXPR:
1435 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1437 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1442 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1443 case EH_FILTER_EXPR:
1444 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1446 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1449 /* Not a live container. */
1457 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1459 tree then_clause, else_clause, cond;
1460 bool save_has_label, then_has_label, else_has_label;
1462 save_has_label = data->has_label;
1463 data->has_label = false;
1464 data->last_goto = NULL;
1466 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1468 then_has_label = data->has_label;
1469 data->has_label = false;
1470 data->last_goto = NULL;
1472 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1474 else_has_label = data->has_label;
1475 data->has_label = save_has_label | then_has_label | else_has_label;
1477 then_clause = COND_EXPR_THEN (*stmt_p);
1478 else_clause = COND_EXPR_ELSE (*stmt_p);
1479 cond = fold (COND_EXPR_COND (*stmt_p));
1481 /* If neither arm does anything at all, we can remove the whole IF. */
1482 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1484 *stmt_p = build_empty_stmt ();
1485 data->repeat = true;
1488 /* If there are no reachable statements in an arm, then we can
1489 zap the entire conditional. */
1490 else if (integer_nonzerop (cond) && !else_has_label)
1492 if (warn_notreached)
1493 remove_useless_stmts_warn_notreached (else_clause);
1494 *stmt_p = then_clause;
1495 data->repeat = true;
1497 else if (integer_zerop (cond) && !then_has_label)
1499 if (warn_notreached)
1500 remove_useless_stmts_warn_notreached (then_clause);
1501 *stmt_p = else_clause;
1502 data->repeat = true;
1505 /* Check a couple of simple things on then/else with single stmts. */
1508 tree then_stmt = expr_only (then_clause);
1509 tree else_stmt = expr_only (else_clause);
1511 /* Notice branches to a common destination. */
1512 if (then_stmt && else_stmt
1513 && TREE_CODE (then_stmt) == GOTO_EXPR
1514 && TREE_CODE (else_stmt) == GOTO_EXPR
1515 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1517 *stmt_p = then_stmt;
1518 data->repeat = true;
1521 /* If the THEN/ELSE clause merely assigns a value to a variable or
1522 parameter which is already known to contain that value, then
1523 remove the useless THEN/ELSE clause. */
1524 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1527 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1528 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1529 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1530 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1532 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1533 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1534 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1535 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1537 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1538 ? then_stmt : else_stmt);
1539 tree *location = (TREE_CODE (cond) == EQ_EXPR
1540 ? &COND_EXPR_THEN (*stmt_p)
1541 : &COND_EXPR_ELSE (*stmt_p));
1544 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1545 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1546 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1547 *location = alloc_stmt_list ();
1551 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1552 would be re-introduced during lowering. */
1553 data->last_goto = NULL;
1558 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1560 bool save_may_branch, save_may_throw;
1561 bool this_may_branch, this_may_throw;
1563 /* Collect may_branch and may_throw information for the body only. */
1564 save_may_branch = data->may_branch;
1565 save_may_throw = data->may_throw;
1566 data->may_branch = false;
1567 data->may_throw = false;
1568 data->last_goto = NULL;
1570 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1572 this_may_branch = data->may_branch;
1573 this_may_throw = data->may_throw;
1574 data->may_branch |= save_may_branch;
1575 data->may_throw |= save_may_throw;
1576 data->last_goto = NULL;
1578 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1580 /* If the body is empty, then we can emit the FINALLY block without
1581 the enclosing TRY_FINALLY_EXPR. */
1582 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1584 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1585 data->repeat = true;
1588 /* If the handler is empty, then we can emit the TRY block without
1589 the enclosing TRY_FINALLY_EXPR. */
1590 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1592 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1593 data->repeat = true;
1596 /* If the body neither throws, nor branches, then we can safely
1597 string the TRY and FINALLY blocks together. */
1598 else if (!this_may_branch && !this_may_throw)
1600 tree stmt = *stmt_p;
1601 *stmt_p = TREE_OPERAND (stmt, 0);
1602 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1603 data->repeat = true;
1609 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1611 bool save_may_throw, this_may_throw;
1612 tree_stmt_iterator i;
1615 /* Collect may_throw information for the body only. */
1616 save_may_throw = data->may_throw;
1617 data->may_throw = false;
1618 data->last_goto = NULL;
1620 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1622 this_may_throw = data->may_throw;
1623 data->may_throw = save_may_throw;
1625 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1626 if (!this_may_throw)
1628 if (warn_notreached)
1629 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1630 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1631 data->repeat = true;
1635 /* Process the catch clause specially. We may be able to tell that
1636 no exceptions propagate past this point. */
1638 this_may_throw = true;
1639 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1640 stmt = tsi_stmt (i);
1641 data->last_goto = NULL;
1643 switch (TREE_CODE (stmt))
1646 for (; !tsi_end_p (i); tsi_next (&i))
1648 stmt = tsi_stmt (i);
1649 /* If we catch all exceptions, then the body does not
1650 propagate exceptions past this point. */
1651 if (CATCH_TYPES (stmt) == NULL)
1652 this_may_throw = false;
1653 data->last_goto = NULL;
1654 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1658 case EH_FILTER_EXPR:
1659 if (EH_FILTER_MUST_NOT_THROW (stmt))
1660 this_may_throw = false;
1661 else if (EH_FILTER_TYPES (stmt) == NULL)
1662 this_may_throw = false;
1663 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1667 /* Otherwise this is a cleanup. */
1668 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1670 /* If the cleanup is empty, then we can emit the TRY block without
1671 the enclosing TRY_CATCH_EXPR. */
1672 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1674 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1675 data->repeat = true;
1679 data->may_throw |= this_may_throw;
1684 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1688 /* First remove anything underneath the BIND_EXPR. */
1689 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1691 /* If the BIND_EXPR has no variables, then we can pull everything
1692 up one level and remove the BIND_EXPR, unless this is the toplevel
1693 BIND_EXPR for the current function or an inlined function.
1695 When this situation occurs we will want to apply this
1696 optimization again. */
1697 block = BIND_EXPR_BLOCK (*stmt_p);
1698 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1699 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1701 || ! BLOCK_ABSTRACT_ORIGIN (block)
1702 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1705 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1706 data->repeat = true;
1712 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1714 tree dest = GOTO_DESTINATION (*stmt_p);
1716 data->may_branch = true;
1717 data->last_goto = NULL;
1719 /* Record the last goto expr, so that we can delete it if unnecessary. */
1720 if (TREE_CODE (dest) == LABEL_DECL)
1721 data->last_goto = stmt_p;
1726 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1728 tree label = LABEL_EXPR_LABEL (*stmt_p);
1730 data->has_label = true;
1732 /* We do want to jump across non-local label receiver code. */
1733 if (DECL_NONLOCAL (label))
1734 data->last_goto = NULL;
1736 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1738 *data->last_goto = build_empty_stmt ();
1739 data->repeat = true;
1742 /* ??? Add something here to delete unused labels. */
1746 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1747 decl. This allows us to eliminate redundant or useless
1748 calls to "const" functions.
1750 Gimplifier already does the same operation, but we may notice functions
1751 being const and pure once their calls has been gimplified, so we need
1752 to update the flag. */
1755 update_call_expr_flags (tree call)
1757 tree decl = get_callee_fndecl (call);
1760 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1761 TREE_SIDE_EFFECTS (call) = 0;
1762 if (TREE_NOTHROW (decl))
1763 TREE_NOTHROW (call) = 1;
1767 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1770 notice_special_calls (tree t)
1772 int flags = call_expr_flags (t);
1774 if (flags & ECF_MAY_BE_ALLOCA)
1775 current_function_calls_alloca = true;
1776 if (flags & ECF_RETURNS_TWICE)
1777 current_function_calls_setjmp = true;
1781 /* Clear flags set by notice_special_calls. Used by dead code removal
1782 to update the flags. */
1785 clear_special_calls (void)
1787 current_function_calls_alloca = false;
1788 current_function_calls_setjmp = false;
1793 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1797 switch (TREE_CODE (t))
1800 remove_useless_stmts_cond (tp, data);
1803 case TRY_FINALLY_EXPR:
1804 remove_useless_stmts_tf (tp, data);
1807 case TRY_CATCH_EXPR:
1808 remove_useless_stmts_tc (tp, data);
1812 remove_useless_stmts_bind (tp, data);
1816 remove_useless_stmts_goto (tp, data);
1820 remove_useless_stmts_label (tp, data);
1825 data->last_goto = NULL;
1826 data->may_branch = true;
1831 data->last_goto = NULL;
1832 notice_special_calls (t);
1833 update_call_expr_flags (t);
1834 if (tree_could_throw_p (t))
1835 data->may_throw = true;
1841 case GIMPLE_MODIFY_STMT:
1842 data->last_goto = NULL;
1844 op = get_call_expr_in (t);
1847 update_call_expr_flags (op);
1848 notice_special_calls (op);
1850 if (tree_could_throw_p (t))
1851 data->may_throw = true;
1854 case STATEMENT_LIST:
1856 tree_stmt_iterator i = tsi_start (t);
1857 while (!tsi_end_p (i))
1860 if (IS_EMPTY_STMT (t))
1866 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1869 if (TREE_CODE (t) == STATEMENT_LIST)
1871 tsi_link_before (&i, t, TSI_SAME_STMT);
1881 data->last_goto = NULL;
1885 data->last_goto = NULL;
1891 remove_useless_stmts (void)
1893 struct rus_data data;
1895 clear_special_calls ();
1899 memset (&data, 0, sizeof (data));
1900 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1902 while (data.repeat);
1907 struct tree_opt_pass pass_remove_useless_stmts =
1909 "useless", /* name */
1911 remove_useless_stmts, /* execute */
1914 0, /* static_pass_number */
1916 PROP_gimple_any, /* properties_required */
1917 0, /* properties_provided */
1918 0, /* properties_destroyed */
1919 0, /* todo_flags_start */
1920 TODO_dump_func, /* todo_flags_finish */
1924 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1927 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1931 /* Since this block is no longer reachable, we can just delete all
1932 of its PHI nodes. */
1933 phi = phi_nodes (bb);
1936 tree next = PHI_CHAIN (phi);
1937 remove_phi_node (phi, NULL_TREE, true);
1941 /* Remove edges to BB's successors. */
1942 while (EDGE_COUNT (bb->succs) > 0)
1943 remove_edge (EDGE_SUCC (bb, 0));
1947 /* Remove statements of basic block BB. */
1950 remove_bb (basic_block bb)
1952 block_stmt_iterator i;
1953 #ifdef USE_MAPPED_LOCATION
1954 source_location loc = UNKNOWN_LOCATION;
1956 source_locus loc = 0;
1961 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1962 if (dump_flags & TDF_DETAILS)
1964 dump_bb (bb, dump_file, 0);
1965 fprintf (dump_file, "\n");
1971 struct loop *loop = bb->loop_father;
1973 /* If a loop gets removed, clean up the information associated
1975 if (loop->latch == bb
1976 || loop->header == bb)
1977 free_numbers_of_iterations_estimates_loop (loop);
1980 /* Remove all the instructions in the block. */
1981 if (bb_stmt_list (bb) != NULL_TREE)
1983 for (i = bsi_start (bb); !bsi_end_p (i);)
1985 tree stmt = bsi_stmt (i);
1986 if (TREE_CODE (stmt) == LABEL_EXPR
1987 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
1988 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
1991 block_stmt_iterator new_bsi;
1993 /* A non-reachable non-local label may still be referenced.
1994 But it no longer needs to carry the extra semantics of
1996 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1998 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
1999 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2002 new_bb = bb->prev_bb;
2003 new_bsi = bsi_start (new_bb);
2004 bsi_remove (&i, false);
2005 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2009 /* Release SSA definitions if we are in SSA. Note that we
2010 may be called when not in SSA. For example,
2011 final_cleanup calls this function via
2012 cleanup_tree_cfg. */
2013 if (gimple_in_ssa_p (cfun))
2014 release_defs (stmt);
2016 bsi_remove (&i, true);
2019 /* Don't warn for removed gotos. Gotos are often removed due to
2020 jump threading, thus resulting in bogus warnings. Not great,
2021 since this way we lose warnings for gotos in the original
2022 program that are indeed unreachable. */
2023 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2025 #ifdef USE_MAPPED_LOCATION
2026 if (EXPR_HAS_LOCATION (stmt))
2027 loc = EXPR_LOCATION (stmt);
2030 t = EXPR_LOCUS (stmt);
2031 if (t && LOCATION_LINE (*t) > 0)
2038 /* If requested, give a warning that the first statement in the
2039 block is unreachable. We walk statements backwards in the
2040 loop above, so the last statement we process is the first statement
2042 #ifdef USE_MAPPED_LOCATION
2043 if (loc > BUILTINS_LOCATION)
2044 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2047 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2050 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2055 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2056 predicate VAL, return the edge that will be taken out of the block.
2057 If VAL does not match a unique edge, NULL is returned. */
2060 find_taken_edge (basic_block bb, tree val)
2064 stmt = last_stmt (bb);
2067 gcc_assert (is_ctrl_stmt (stmt));
2070 if (! is_gimple_min_invariant (val))
2073 if (TREE_CODE (stmt) == COND_EXPR)
2074 return find_taken_edge_cond_expr (bb, val);
2076 if (TREE_CODE (stmt) == SWITCH_EXPR)
2077 return find_taken_edge_switch_expr (bb, val);
2079 if (computed_goto_p (stmt))
2081 /* Only optimize if the argument is a label, if the argument is
2082 not a label then we can not construct a proper CFG.
2084 It may be the case that we only need to allow the LABEL_REF to
2085 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2086 appear inside a LABEL_EXPR just to be safe. */
2087 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2088 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2089 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2096 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2097 statement, determine which of the outgoing edges will be taken out of the
2098 block. Return NULL if either edge may be taken. */
2101 find_taken_edge_computed_goto (basic_block bb, tree val)
2106 dest = label_to_block (val);
2109 e = find_edge (bb, dest);
2110 gcc_assert (e != NULL);
2116 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2117 statement, determine which of the two edges will be taken out of the
2118 block. Return NULL if either edge may be taken. */
2121 find_taken_edge_cond_expr (basic_block bb, tree val)
2123 edge true_edge, false_edge;
2125 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2127 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2128 return (integer_zerop (val) ? false_edge : true_edge);
2131 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2132 statement, determine which edge will be taken out of the block. Return
2133 NULL if any edge may be taken. */
2136 find_taken_edge_switch_expr (basic_block bb, tree val)
2138 tree switch_expr, taken_case;
2139 basic_block dest_bb;
2142 switch_expr = last_stmt (bb);
2143 taken_case = find_case_label_for_value (switch_expr, val);
2144 dest_bb = label_to_block (CASE_LABEL (taken_case));
2146 e = find_edge (bb, dest_bb);
2152 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2153 We can make optimal use here of the fact that the case labels are
2154 sorted: We can do a binary search for a case matching VAL. */
2157 find_case_label_for_value (tree switch_expr, tree val)
2159 tree vec = SWITCH_LABELS (switch_expr);
2160 size_t low, high, n = TREE_VEC_LENGTH (vec);
2161 tree default_case = TREE_VEC_ELT (vec, n - 1);
2163 for (low = -1, high = n - 1; high - low > 1; )
2165 size_t i = (high + low) / 2;
2166 tree t = TREE_VEC_ELT (vec, i);
2169 /* Cache the result of comparing CASE_LOW and val. */
2170 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2177 if (CASE_HIGH (t) == NULL)
2179 /* A singe-valued case label. */
2185 /* A case range. We can only handle integer ranges. */
2186 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2191 return default_case;
2197 /*---------------------------------------------------------------------------
2199 ---------------------------------------------------------------------------*/
2201 /* Dump tree-specific information of block BB to file OUTF. */
2204 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2206 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2210 /* Dump a basic block on stderr. */
2213 debug_tree_bb (basic_block bb)
2215 dump_bb (bb, stderr, 0);
2219 /* Dump basic block with index N on stderr. */
2222 debug_tree_bb_n (int n)
2224 debug_tree_bb (BASIC_BLOCK (n));
2225 return BASIC_BLOCK (n);
2229 /* Dump the CFG on stderr.
2231 FLAGS are the same used by the tree dumping functions
2232 (see TDF_* in tree-pass.h). */
2235 debug_tree_cfg (int flags)
2237 dump_tree_cfg (stderr, flags);
2241 /* Dump the program showing basic block boundaries on the given FILE.
2243 FLAGS are the same used by the tree dumping functions (see TDF_* in
2247 dump_tree_cfg (FILE *file, int flags)
2249 if (flags & TDF_DETAILS)
2251 const char *funcname
2252 = lang_hooks.decl_printable_name (current_function_decl, 2);
2255 fprintf (file, ";; Function %s\n\n", funcname);
2256 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2257 n_basic_blocks, n_edges, last_basic_block);
2259 brief_dump_cfg (file);
2260 fprintf (file, "\n");
2263 if (flags & TDF_STATS)
2264 dump_cfg_stats (file);
2266 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2270 /* Dump CFG statistics on FILE. */
2273 dump_cfg_stats (FILE *file)
2275 static long max_num_merged_labels = 0;
2276 unsigned long size, total = 0;
2279 const char * const fmt_str = "%-30s%-13s%12s\n";
2280 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2281 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2282 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2283 const char *funcname
2284 = lang_hooks.decl_printable_name (current_function_decl, 2);
2287 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2289 fprintf (file, "---------------------------------------------------------\n");
2290 fprintf (file, fmt_str, "", " Number of ", "Memory");
2291 fprintf (file, fmt_str, "", " instances ", "used ");
2292 fprintf (file, "---------------------------------------------------------\n");
2294 size = n_basic_blocks * sizeof (struct basic_block_def);
2296 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2297 SCALE (size), LABEL (size));
2301 num_edges += EDGE_COUNT (bb->succs);
2302 size = num_edges * sizeof (struct edge_def);
2304 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2306 fprintf (file, "---------------------------------------------------------\n");
2307 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2309 fprintf (file, "---------------------------------------------------------\n");
2310 fprintf (file, "\n");
2312 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2313 max_num_merged_labels = cfg_stats.num_merged_labels;
2315 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2316 cfg_stats.num_merged_labels, max_num_merged_labels);
2318 fprintf (file, "\n");
2322 /* Dump CFG statistics on stderr. Keep extern so that it's always
2323 linked in the final executable. */
2326 debug_cfg_stats (void)
2328 dump_cfg_stats (stderr);
2332 /* Dump the flowgraph to a .vcg FILE. */
2335 tree_cfg2vcg (FILE *file)
2340 const char *funcname
2341 = lang_hooks.decl_printable_name (current_function_decl, 2);
2343 /* Write the file header. */
2344 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2345 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2346 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2348 /* Write blocks and edges. */
2349 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2351 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2354 if (e->flags & EDGE_FAKE)
2355 fprintf (file, " linestyle: dotted priority: 10");
2357 fprintf (file, " linestyle: solid priority: 100");
2359 fprintf (file, " }\n");
2365 enum tree_code head_code, end_code;
2366 const char *head_name, *end_name;
2369 tree first = first_stmt (bb);
2370 tree last = last_stmt (bb);
2374 head_code = TREE_CODE (first);
2375 head_name = tree_code_name[head_code];
2376 head_line = get_lineno (first);
2379 head_name = "no-statement";
2383 end_code = TREE_CODE (last);
2384 end_name = tree_code_name[end_code];
2385 end_line = get_lineno (last);
2388 end_name = "no-statement";
2390 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2391 bb->index, bb->index, head_name, head_line, end_name,
2394 FOR_EACH_EDGE (e, ei, bb->succs)
2396 if (e->dest == EXIT_BLOCK_PTR)
2397 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2399 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2401 if (e->flags & EDGE_FAKE)
2402 fprintf (file, " priority: 10 linestyle: dotted");
2404 fprintf (file, " priority: 100 linestyle: solid");
2406 fprintf (file, " }\n");
2409 if (bb->next_bb != EXIT_BLOCK_PTR)
2413 fputs ("}\n\n", file);
2418 /*---------------------------------------------------------------------------
2419 Miscellaneous helpers
2420 ---------------------------------------------------------------------------*/
2422 /* Return true if T represents a stmt that always transfers control. */
2425 is_ctrl_stmt (tree t)
2427 return (TREE_CODE (t) == COND_EXPR
2428 || TREE_CODE (t) == SWITCH_EXPR
2429 || TREE_CODE (t) == GOTO_EXPR
2430 || TREE_CODE (t) == RETURN_EXPR
2431 || TREE_CODE (t) == RESX_EXPR);
2435 /* Return true if T is a statement that may alter the flow of control
2436 (e.g., a call to a non-returning function). */
2439 is_ctrl_altering_stmt (tree t)
2444 call = get_call_expr_in (t);
2447 /* A non-pure/const CALL_EXPR alters flow control if the current
2448 function has nonlocal labels. */
2449 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2452 /* A CALL_EXPR also alters control flow if it does not return. */
2453 if (call_expr_flags (call) & ECF_NORETURN)
2457 /* OpenMP directives alter control flow. */
2458 if (OMP_DIRECTIVE_P (t))
2461 /* If a statement can throw, it alters control flow. */
2462 return tree_can_throw_internal (t);
2466 /* Return true if T is a computed goto. */
2469 computed_goto_p (tree t)
2471 return (TREE_CODE (t) == GOTO_EXPR
2472 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2476 /* Return true if T is a simple local goto. */
2479 simple_goto_p (tree t)
2481 return (TREE_CODE (t) == GOTO_EXPR
2482 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2486 /* Return true if T can make an abnormal transfer of control flow.
2487 Transfers of control flow associated with EH are excluded. */
2490 tree_can_make_abnormal_goto (tree t)
2492 if (computed_goto_p (t))
2494 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2495 t = GIMPLE_STMT_OPERAND (t, 1);
2496 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2497 t = TREE_OPERAND (t, 0);
2498 if (TREE_CODE (t) == CALL_EXPR)
2499 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2504 /* Return true if T should start a new basic block. PREV_T is the
2505 statement preceding T. It is used when T is a label or a case label.
2506 Labels should only start a new basic block if their previous statement
2507 wasn't a label. Otherwise, sequence of labels would generate
2508 unnecessary basic blocks that only contain a single label. */
2511 stmt_starts_bb_p (tree t, tree prev_t)
2516 /* LABEL_EXPRs start a new basic block only if the preceding
2517 statement wasn't a label of the same type. This prevents the
2518 creation of consecutive blocks that have nothing but a single
2520 if (TREE_CODE (t) == LABEL_EXPR)
2522 /* Nonlocal and computed GOTO targets always start a new block. */
2523 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2524 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2527 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2529 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2532 cfg_stats.num_merged_labels++;
2543 /* Return true if T should end a basic block. */
2546 stmt_ends_bb_p (tree t)
2548 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2551 /* Remove block annotations and other datastructures. */
2554 delete_tree_cfg_annotations (void)
2557 block_stmt_iterator bsi;
2559 /* Remove annotations from every tree in the function. */
2561 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2563 tree stmt = bsi_stmt (bsi);
2564 ggc_free (stmt->base.ann);
2565 stmt->base.ann = NULL;
2567 label_to_block_map = NULL;
2571 /* Return the first statement in basic block BB. */
2574 first_stmt (basic_block bb)
2576 block_stmt_iterator i = bsi_start (bb);
2577 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2581 /* Return the last statement in basic block BB. */
2584 last_stmt (basic_block bb)
2586 block_stmt_iterator b = bsi_last (bb);
2587 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2591 /* Return the last statement of an otherwise empty block. Return NULL
2592 if the block is totally empty, or if it contains more than one
2596 last_and_only_stmt (basic_block bb)
2598 block_stmt_iterator i = bsi_last (bb);
2604 last = bsi_stmt (i);
2609 /* Empty statements should no longer appear in the instruction stream.
2610 Everything that might have appeared before should be deleted by
2611 remove_useless_stmts, and the optimizers should just bsi_remove
2612 instead of smashing with build_empty_stmt.
2614 Thus the only thing that should appear here in a block containing
2615 one executable statement is a label. */
2616 prev = bsi_stmt (i);
2617 if (TREE_CODE (prev) == LABEL_EXPR)
2624 /* Mark BB as the basic block holding statement T. */
2627 set_bb_for_stmt (tree t, basic_block bb)
2629 if (TREE_CODE (t) == PHI_NODE)
2631 else if (TREE_CODE (t) == STATEMENT_LIST)
2633 tree_stmt_iterator i;
2634 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2635 set_bb_for_stmt (tsi_stmt (i), bb);
2639 stmt_ann_t ann = get_stmt_ann (t);
2642 /* If the statement is a label, add the label to block-to-labels map
2643 so that we can speed up edge creation for GOTO_EXPRs. */
2644 if (TREE_CODE (t) == LABEL_EXPR)
2648 t = LABEL_EXPR_LABEL (t);
2649 uid = LABEL_DECL_UID (t);
2652 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2653 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2654 if (old_len <= (unsigned) uid)
2656 unsigned new_len = 3 * uid / 2;
2658 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2663 /* We're moving an existing label. Make sure that we've
2664 removed it from the old block. */
2666 || !VEC_index (basic_block, label_to_block_map, uid));
2667 VEC_replace (basic_block, label_to_block_map, uid, bb);
2672 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2673 from one basic block to another.
2674 For BB splitting we can run into quadratic case, so performance is quite
2675 important and knowing that the tables are big enough, change_bb_for_stmt
2676 can inline as leaf function. */
2678 change_bb_for_stmt (tree t, basic_block bb)
2680 get_stmt_ann (t)->bb = bb;
2681 if (TREE_CODE (t) == LABEL_EXPR)
2682 VEC_replace (basic_block, label_to_block_map,
2683 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2686 /* Finds iterator for STMT. */
2688 extern block_stmt_iterator
2689 bsi_for_stmt (tree stmt)
2691 block_stmt_iterator bsi;
2693 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2694 if (bsi_stmt (bsi) == stmt)
2700 /* Mark statement T as modified, and update it. */
2702 update_modified_stmts (tree t)
2704 if (!ssa_operands_active ())
2706 if (TREE_CODE (t) == STATEMENT_LIST)
2708 tree_stmt_iterator i;
2710 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2712 stmt = tsi_stmt (i);
2713 update_stmt_if_modified (stmt);
2717 update_stmt_if_modified (t);
2720 /* Insert statement (or statement list) T before the statement
2721 pointed-to by iterator I. M specifies how to update iterator I
2722 after insertion (see enum bsi_iterator_update). */
2725 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2727 set_bb_for_stmt (t, i->bb);
2728 update_modified_stmts (t);
2729 tsi_link_before (&i->tsi, t, m);
2733 /* Insert statement (or statement list) T after the statement
2734 pointed-to by iterator I. M specifies how to update iterator I
2735 after insertion (see enum bsi_iterator_update). */
2738 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2740 set_bb_for_stmt (t, i->bb);
2741 update_modified_stmts (t);
2742 tsi_link_after (&i->tsi, t, m);
2746 /* Remove the statement pointed to by iterator I. The iterator is updated
2747 to the next statement.
2749 When REMOVE_EH_INFO is true we remove the statement pointed to by
2750 iterator I from the EH tables. Otherwise we do not modify the EH
2753 Generally, REMOVE_EH_INFO should be true when the statement is going to
2754 be removed from the IL and not reinserted elsewhere. */
2757 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2759 tree t = bsi_stmt (*i);
2760 set_bb_for_stmt (t, NULL);
2761 delink_stmt_imm_use (t);
2762 tsi_delink (&i->tsi);
2763 mark_stmt_modified (t);
2766 remove_stmt_from_eh_region (t);
2767 gimple_remove_stmt_histograms (cfun, t);
2772 /* Move the statement at FROM so it comes right after the statement at TO. */
2775 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2777 tree stmt = bsi_stmt (*from);
2778 bsi_remove (from, false);
2779 /* We must have BSI_NEW_STMT here, as bsi_move_after is sometimes used to
2780 move statements to an empty block. */
2781 bsi_insert_after (to, stmt, BSI_NEW_STMT);
2785 /* Move the statement at FROM so it comes right before the statement at TO. */
2788 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2790 tree stmt = bsi_stmt (*from);
2791 bsi_remove (from, false);
2792 /* For consistency with bsi_move_after, it might be better to have
2793 BSI_NEW_STMT here; however, that breaks several places that expect
2794 that TO does not change. */
2795 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2799 /* Move the statement at FROM to the end of basic block BB. */
2802 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2804 block_stmt_iterator last = bsi_last (bb);
2806 /* Have to check bsi_end_p because it could be an empty block. */
2807 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2808 bsi_move_before (from, &last);
2810 bsi_move_after (from, &last);
2814 /* Replace the contents of the statement pointed to by iterator BSI
2815 with STMT. If UPDATE_EH_INFO is true, the exception handling
2816 information of the original statement is moved to the new statement. */
2819 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2822 tree orig_stmt = bsi_stmt (*bsi);
2824 if (stmt == orig_stmt)
2826 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2827 set_bb_for_stmt (stmt, bsi->bb);
2829 /* Preserve EH region information from the original statement, if
2830 requested by the caller. */
2833 eh_region = lookup_stmt_eh_region (orig_stmt);
2836 remove_stmt_from_eh_region (orig_stmt);
2837 add_stmt_to_eh_region (stmt, eh_region);
2841 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2842 gimple_remove_stmt_histograms (cfun, orig_stmt);
2843 delink_stmt_imm_use (orig_stmt);
2844 *bsi_stmt_ptr (*bsi) = stmt;
2845 mark_stmt_modified (stmt);
2846 update_modified_stmts (stmt);
2850 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2851 is made to place the statement in an existing basic block, but
2852 sometimes that isn't possible. When it isn't possible, the edge is
2853 split and the statement is added to the new block.
2855 In all cases, the returned *BSI points to the correct location. The
2856 return value is true if insertion should be done after the location,
2857 or false if it should be done before the location. If new basic block
2858 has to be created, it is stored in *NEW_BB. */
2861 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2862 basic_block *new_bb)
2864 basic_block dest, src;
2870 /* If the destination has one predecessor which has no PHI nodes,
2871 insert there. Except for the exit block.
2873 The requirement for no PHI nodes could be relaxed. Basically we
2874 would have to examine the PHIs to prove that none of them used
2875 the value set by the statement we want to insert on E. That
2876 hardly seems worth the effort. */
2877 if (single_pred_p (dest)
2878 && ! phi_nodes (dest)
2879 && dest != EXIT_BLOCK_PTR)
2881 *bsi = bsi_start (dest);
2882 if (bsi_end_p (*bsi))
2885 /* Make sure we insert after any leading labels. */
2886 tmp = bsi_stmt (*bsi);
2887 while (TREE_CODE (tmp) == LABEL_EXPR)
2890 if (bsi_end_p (*bsi))
2892 tmp = bsi_stmt (*bsi);
2895 if (bsi_end_p (*bsi))
2897 *bsi = bsi_last (dest);
2904 /* If the source has one successor, the edge is not abnormal and
2905 the last statement does not end a basic block, insert there.
2906 Except for the entry block. */
2908 if ((e->flags & EDGE_ABNORMAL) == 0
2909 && single_succ_p (src)
2910 && src != ENTRY_BLOCK_PTR)
2912 *bsi = bsi_last (src);
2913 if (bsi_end_p (*bsi))
2916 tmp = bsi_stmt (*bsi);
2917 if (!stmt_ends_bb_p (tmp))
2920 /* Insert code just before returning the value. We may need to decompose
2921 the return in the case it contains non-trivial operand. */
2922 if (TREE_CODE (tmp) == RETURN_EXPR)
2924 tree op = TREE_OPERAND (tmp, 0);
2925 if (op && !is_gimple_val (op))
2927 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
2928 bsi_insert_before (bsi, op, BSI_NEW_STMT);
2929 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
2936 /* Otherwise, create a new basic block, and split this edge. */
2937 dest = split_edge (e);
2940 e = single_pred_edge (dest);
2945 /* This routine will commit all pending edge insertions, creating any new
2946 basic blocks which are necessary. */
2949 bsi_commit_edge_inserts (void)
2955 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
2958 FOR_EACH_EDGE (e, ei, bb->succs)
2959 bsi_commit_one_edge_insert (e, NULL);
2963 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2964 to this block, otherwise set it to NULL. */
2967 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
2971 if (PENDING_STMT (e))
2973 block_stmt_iterator bsi;
2974 tree stmt = PENDING_STMT (e);
2976 PENDING_STMT (e) = NULL_TREE;
2978 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
2979 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
2981 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
2986 /* Add STMT to the pending list of edge E. No actual insertion is
2987 made until a call to bsi_commit_edge_inserts () is made. */
2990 bsi_insert_on_edge (edge e, tree stmt)
2992 append_to_statement_list (stmt, &PENDING_STMT (e));
2995 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
2996 block has to be created, it is returned. */
2999 bsi_insert_on_edge_immediate (edge e, tree stmt)
3001 block_stmt_iterator bsi;
3002 basic_block new_bb = NULL;
3004 gcc_assert (!PENDING_STMT (e));
3006 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3007 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3009 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3014 /*---------------------------------------------------------------------------
3015 Tree specific functions for CFG manipulation
3016 ---------------------------------------------------------------------------*/
3018 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3021 reinstall_phi_args (edge new_edge, edge old_edge)
3025 if (!PENDING_STMT (old_edge))
3028 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3030 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3032 tree result = TREE_PURPOSE (var);
3033 tree arg = TREE_VALUE (var);
3035 gcc_assert (result == PHI_RESULT (phi));
3037 add_phi_arg (phi, arg, new_edge);
3040 PENDING_STMT (old_edge) = NULL;
3043 /* Returns the basic block after which the new basic block created
3044 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3045 near its "logical" location. This is of most help to humans looking
3046 at debugging dumps. */
3049 split_edge_bb_loc (edge edge_in)
3051 basic_block dest = edge_in->dest;
3053 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3054 return edge_in->src;
3056 return dest->prev_bb;
3059 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3060 Abort on abnormal edges. */
3063 tree_split_edge (edge edge_in)
3065 basic_block new_bb, after_bb, dest;
3068 /* Abnormal edges cannot be split. */
3069 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3071 dest = edge_in->dest;
3073 after_bb = split_edge_bb_loc (edge_in);
3075 new_bb = create_empty_bb (after_bb);
3076 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3077 new_bb->count = edge_in->count;
3078 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3079 new_edge->probability = REG_BR_PROB_BASE;
3080 new_edge->count = edge_in->count;
3082 e = redirect_edge_and_branch (edge_in, new_bb);
3083 gcc_assert (e == edge_in);
3084 reinstall_phi_args (new_edge, e);
3089 /* Callback for walk_tree, check that all elements with address taken are
3090 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3091 inside a PHI node. */
3094 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3097 bool in_phi = (data != NULL);
3102 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3103 #define CHECK_OP(N, MSG) \
3104 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3105 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3107 switch (TREE_CODE (t))
3110 if (SSA_NAME_IN_FREE_LIST (t))
3112 error ("SSA name in freelist but still referenced");
3118 x = fold (ASSERT_EXPR_COND (t));
3119 if (x == boolean_false_node)
3121 error ("ASSERT_EXPR with an always-false condition");
3129 case GIMPLE_MODIFY_STMT:
3130 x = GIMPLE_STMT_OPERAND (t, 0);
3131 if (TREE_CODE (x) == BIT_FIELD_REF
3132 && is_gimple_reg (TREE_OPERAND (x, 0)))
3134 error ("GIMPLE register modified with BIT_FIELD_REF");
3143 bool old_side_effects;
3146 bool new_side_effects;
3148 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3149 dead PHIs that take the address of something. But if the PHI
3150 result is dead, the fact that it takes the address of anything
3151 is irrelevant. Because we can not tell from here if a PHI result
3152 is dead, we just skip this check for PHIs altogether. This means
3153 we may be missing "valid" checks, but what can you do?
3154 This was PR19217. */
3158 old_invariant = TREE_INVARIANT (t);
3159 old_constant = TREE_CONSTANT (t);
3160 old_side_effects = TREE_SIDE_EFFECTS (t);
3162 recompute_tree_invariant_for_addr_expr (t);
3163 new_invariant = TREE_INVARIANT (t);
3164 new_side_effects = TREE_SIDE_EFFECTS (t);
3165 new_constant = TREE_CONSTANT (t);
3167 if (old_invariant != new_invariant)
3169 error ("invariant not recomputed when ADDR_EXPR changed");
3173 if (old_constant != new_constant)
3175 error ("constant not recomputed when ADDR_EXPR changed");
3178 if (old_side_effects != new_side_effects)
3180 error ("side effects not recomputed when ADDR_EXPR changed");
3184 /* Skip any references (they will be checked when we recurse down the
3185 tree) and ensure that any variable used as a prefix is marked
3187 for (x = TREE_OPERAND (t, 0);
3188 handled_component_p (x);
3189 x = TREE_OPERAND (x, 0))
3192 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3194 if (!TREE_ADDRESSABLE (x))
3196 error ("address taken, but ADDRESSABLE bit not set");
3203 x = COND_EXPR_COND (t);
3204 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3206 error ("non-boolean used in condition");
3209 if (!is_gimple_condexpr (x))
3211 error ("invalid conditional operand");
3218 case FIX_TRUNC_EXPR:
3223 case NON_LVALUE_EXPR:
3224 case TRUTH_NOT_EXPR:
3225 CHECK_OP (0, "invalid operand to unary operator");
3232 case ARRAY_RANGE_REF:
3234 case VIEW_CONVERT_EXPR:
3235 /* We have a nest of references. Verify that each of the operands
3236 that determine where to reference is either a constant or a variable,
3237 verify that the base is valid, and then show we've already checked
3239 while (handled_component_p (t))
3241 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3242 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3243 else if (TREE_CODE (t) == ARRAY_REF
3244 || TREE_CODE (t) == ARRAY_RANGE_REF)
3246 CHECK_OP (1, "invalid array index");
3247 if (TREE_OPERAND (t, 2))
3248 CHECK_OP (2, "invalid array lower bound");
3249 if (TREE_OPERAND (t, 3))
3250 CHECK_OP (3, "invalid array stride");
3252 else if (TREE_CODE (t) == BIT_FIELD_REF)
3254 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3255 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3258 t = TREE_OPERAND (t, 0);
3261 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3263 error ("invalid reference prefix");
3275 case UNORDERED_EXPR:
3286 case TRUNC_DIV_EXPR:
3288 case FLOOR_DIV_EXPR:
3289 case ROUND_DIV_EXPR:
3290 case TRUNC_MOD_EXPR:
3292 case FLOOR_MOD_EXPR:
3293 case ROUND_MOD_EXPR:
3295 case EXACT_DIV_EXPR:
3305 CHECK_OP (0, "invalid operand to binary operator");
3306 CHECK_OP (1, "invalid operand to binary operator");
3310 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3323 /* Verify STMT, return true if STMT is not in GIMPLE form.
3324 TODO: Implement type checking. */
3327 verify_stmt (tree stmt, bool last_in_block)
3331 if (OMP_DIRECTIVE_P (stmt))
3333 /* OpenMP directives are validated by the FE and never operated
3334 on by the optimizers. Furthermore, OMP_FOR may contain
3335 non-gimple expressions when the main index variable has had
3336 its address taken. This does not affect the loop itself
3337 because the header of an OMP_FOR is merely used to determine
3338 how to setup the parallel iteration. */
3342 if (!is_gimple_stmt (stmt))
3344 error ("is not a valid GIMPLE statement");
3348 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3351 debug_generic_stmt (addr);
3355 /* If the statement is marked as part of an EH region, then it is
3356 expected that the statement could throw. Verify that when we
3357 have optimizations that simplify statements such that we prove
3358 that they cannot throw, that we update other data structures
3360 if (lookup_stmt_eh_region (stmt) >= 0)
3362 if (!tree_could_throw_p (stmt))
3364 error ("statement marked for throw, but doesn%'t");
3367 if (!last_in_block && tree_can_throw_internal (stmt))
3369 error ("statement marked for throw in middle of block");
3377 debug_generic_stmt (stmt);
3382 /* Return true when the T can be shared. */
3385 tree_node_can_be_shared (tree t)
3387 if (IS_TYPE_OR_DECL_P (t)
3388 || is_gimple_min_invariant (t)
3389 || TREE_CODE (t) == SSA_NAME
3390 || t == error_mark_node
3391 || TREE_CODE (t) == IDENTIFIER_NODE)
3394 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3397 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3398 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3399 || TREE_CODE (t) == COMPONENT_REF
3400 || TREE_CODE (t) == REALPART_EXPR
3401 || TREE_CODE (t) == IMAGPART_EXPR)
3402 t = TREE_OPERAND (t, 0);
3411 /* Called via walk_trees. Verify tree sharing. */
3414 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3416 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3418 if (tree_node_can_be_shared (*tp))
3420 *walk_subtrees = false;
3424 if (pointer_set_insert (visited, *tp))
3431 /* Helper function for verify_gimple_tuples. */
3434 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3435 void *data ATTRIBUTE_UNUSED)
3437 switch (TREE_CODE (*tp))
3440 error ("unexpected non-tuple");
3450 /* Verify that there are no trees that should have been converted to
3451 gimple tuples. Return true if T contains a node that should have
3452 been converted to a gimple tuple, but hasn't. */
3455 verify_gimple_tuples (tree t)
3457 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3460 static bool eh_error_found;
3462 verify_eh_throw_stmt_node (void **slot, void *data)
3464 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3465 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3467 if (!pointer_set_contains (visited, node->stmt))
3469 error ("Dead STMT in EH table");
3470 debug_generic_stmt (node->stmt);
3471 eh_error_found = true;
3476 /* Verify the GIMPLE statement chain. */
3482 block_stmt_iterator bsi;
3484 struct pointer_set_t *visited, *visited_stmts;
3487 timevar_push (TV_TREE_STMT_VERIFY);
3488 visited = pointer_set_create ();
3489 visited_stmts = pointer_set_create ();
3496 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3498 int phi_num_args = PHI_NUM_ARGS (phi);
3500 pointer_set_insert (visited_stmts, phi);
3501 if (bb_for_stmt (phi) != bb)
3503 error ("bb_for_stmt (phi) is set to a wrong basic block");
3507 for (i = 0; i < phi_num_args; i++)
3509 tree t = PHI_ARG_DEF (phi, i);
3512 /* Addressable variables do have SSA_NAMEs but they
3513 are not considered gimple values. */
3514 if (TREE_CODE (t) != SSA_NAME
3515 && TREE_CODE (t) != FUNCTION_DECL
3516 && !is_gimple_val (t))
3518 error ("PHI def is not a GIMPLE value");
3519 debug_generic_stmt (phi);
3520 debug_generic_stmt (t);
3524 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3527 debug_generic_stmt (addr);
3531 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3534 error ("incorrect sharing of tree nodes");
3535 debug_generic_stmt (phi);
3536 debug_generic_stmt (addr);
3542 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3544 tree stmt = bsi_stmt (bsi);
3546 pointer_set_insert (visited_stmts, stmt);
3547 err |= verify_gimple_tuples (stmt);
3549 if (bb_for_stmt (stmt) != bb)
3551 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3556 err |= verify_stmt (stmt, bsi_end_p (bsi));
3557 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3560 error ("incorrect sharing of tree nodes");
3561 debug_generic_stmt (stmt);
3562 debug_generic_stmt (addr);
3567 eh_error_found = false;
3568 if (get_eh_throw_stmt_table (cfun))
3569 htab_traverse (get_eh_throw_stmt_table (cfun),
3570 verify_eh_throw_stmt_node,
3573 if (err | eh_error_found)
3574 internal_error ("verify_stmts failed");
3576 pointer_set_destroy (visited);
3577 pointer_set_destroy (visited_stmts);
3578 verify_histograms ();
3579 timevar_pop (TV_TREE_STMT_VERIFY);
3583 /* Verifies that the flow information is OK. */
3586 tree_verify_flow_info (void)
3590 block_stmt_iterator bsi;
3595 if (ENTRY_BLOCK_PTR->il.tree)
3597 error ("ENTRY_BLOCK has IL associated with it");
3601 if (EXIT_BLOCK_PTR->il.tree)
3603 error ("EXIT_BLOCK has IL associated with it");
3607 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3608 if (e->flags & EDGE_FALLTHRU)
3610 error ("fallthru to exit from bb %d", e->src->index);
3616 bool found_ctrl_stmt = false;
3620 /* Skip labels on the start of basic block. */
3621 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3623 tree prev_stmt = stmt;
3625 stmt = bsi_stmt (bsi);
3627 if (TREE_CODE (stmt) != LABEL_EXPR)
3630 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3632 error ("nonlocal label ");
3633 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3634 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3639 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3642 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3643 fprintf (stderr, " to block does not match in bb %d",
3648 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3649 != current_function_decl)
3652 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3653 fprintf (stderr, " has incorrect context in bb %d",
3659 /* Verify that body of basic block BB is free of control flow. */
3660 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3662 tree stmt = bsi_stmt (bsi);
3664 if (found_ctrl_stmt)
3666 error ("control flow in the middle of basic block %d",
3671 if (stmt_ends_bb_p (stmt))
3672 found_ctrl_stmt = true;
3674 if (TREE_CODE (stmt) == LABEL_EXPR)
3677 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3678 fprintf (stderr, " in the middle of basic block %d", bb->index);
3683 bsi = bsi_last (bb);
3684 if (bsi_end_p (bsi))
3687 stmt = bsi_stmt (bsi);
3689 err |= verify_eh_edges (stmt);
3691 if (is_ctrl_stmt (stmt))
3693 FOR_EACH_EDGE (e, ei, bb->succs)
3694 if (e->flags & EDGE_FALLTHRU)
3696 error ("fallthru edge after a control statement in bb %d",
3702 if (TREE_CODE (stmt) != COND_EXPR)
3704 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3705 after anything else but if statement. */
3706 FOR_EACH_EDGE (e, ei, bb->succs)
3707 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3709 error ("true/false edge after a non-COND_EXPR in bb %d",
3715 switch (TREE_CODE (stmt))
3722 if (COND_EXPR_THEN (stmt) != NULL_TREE
3723 || COND_EXPR_ELSE (stmt) != NULL_TREE)
3725 error ("COND_EXPR with code in branches at the end of bb %d",
3730 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3732 if (!true_edge || !false_edge
3733 || !(true_edge->flags & EDGE_TRUE_VALUE)
3734 || !(false_edge->flags & EDGE_FALSE_VALUE)
3735 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3736 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3737 || EDGE_COUNT (bb->succs) >= 3)
3739 error ("wrong outgoing edge flags at end of bb %d",
3747 if (simple_goto_p (stmt))
3749 error ("explicit goto at end of bb %d", bb->index);
3754 /* FIXME. We should double check that the labels in the
3755 destination blocks have their address taken. */
3756 FOR_EACH_EDGE (e, ei, bb->succs)
3757 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3758 | EDGE_FALSE_VALUE))
3759 || !(e->flags & EDGE_ABNORMAL))
3761 error ("wrong outgoing edge flags at end of bb %d",
3769 if (!single_succ_p (bb)
3770 || (single_succ_edge (bb)->flags
3771 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3772 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3774 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3777 if (single_succ (bb) != EXIT_BLOCK_PTR)
3779 error ("return edge does not point to exit in bb %d",
3792 vec = SWITCH_LABELS (stmt);
3793 n = TREE_VEC_LENGTH (vec);
3795 /* Mark all the destination basic blocks. */
3796 for (i = 0; i < n; ++i)
3798 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3799 basic_block label_bb = label_to_block (lab);
3801 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3802 label_bb->aux = (void *)1;
3805 /* Verify that the case labels are sorted. */
3806 prev = TREE_VEC_ELT (vec, 0);
3807 for (i = 1; i < n - 1; ++i)
3809 tree c = TREE_VEC_ELT (vec, i);
3812 error ("found default case not at end of case vector");
3816 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3818 error ("case labels not sorted: ");
3819 print_generic_expr (stderr, prev, 0);
3820 fprintf (stderr," is greater than ");
3821 print_generic_expr (stderr, c, 0);
3822 fprintf (stderr," but comes before it.\n");
3827 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3829 error ("no default case found at end of case vector");
3833 FOR_EACH_EDGE (e, ei, bb->succs)
3837 error ("extra outgoing edge %d->%d",
3838 bb->index, e->dest->index);
3841 e->dest->aux = (void *)2;
3842 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3843 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3845 error ("wrong outgoing edge flags at end of bb %d",
3851 /* Check that we have all of them. */
3852 for (i = 0; i < n; ++i)
3854 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3855 basic_block label_bb = label_to_block (lab);
3857 if (label_bb->aux != (void *)2)
3859 error ("missing edge %i->%i",
3860 bb->index, label_bb->index);
3865 FOR_EACH_EDGE (e, ei, bb->succs)
3866 e->dest->aux = (void *)0;
3873 if (dom_info_state (CDI_DOMINATORS) >= DOM_NO_FAST_QUERY)
3874 verify_dominators (CDI_DOMINATORS);
3880 /* Updates phi nodes after creating a forwarder block joined
3881 by edge FALLTHRU. */
3884 tree_make_forwarder_block (edge fallthru)
3888 basic_block dummy, bb;
3889 tree phi, new_phi, var;
3891 dummy = fallthru->src;
3892 bb = fallthru->dest;
3894 if (single_pred_p (bb))
3897 /* If we redirected a branch we must create new PHI nodes at the
3899 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3901 var = PHI_RESULT (phi);
3902 new_phi = create_phi_node (var, bb);
3903 SSA_NAME_DEF_STMT (var) = new_phi;
3904 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3905 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3908 /* Ensure that the PHI node chain is in the same order. */
3909 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3911 /* Add the arguments we have stored on edges. */
3912 FOR_EACH_EDGE (e, ei, bb->preds)
3917 flush_pending_stmts (e);
3922 /* Return a non-special label in the head of basic block BLOCK.
3923 Create one if it doesn't exist. */
3926 tree_block_label (basic_block bb)
3928 block_stmt_iterator i, s = bsi_start (bb);
3932 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
3934 stmt = bsi_stmt (i);
3935 if (TREE_CODE (stmt) != LABEL_EXPR)
3937 label = LABEL_EXPR_LABEL (stmt);
3938 if (!DECL_NONLOCAL (label))
3941 bsi_move_before (&i, &s);
3946 label = create_artificial_label ();
3947 stmt = build1 (LABEL_EXPR, void_type_node, label);
3948 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
3953 /* Attempt to perform edge redirection by replacing a possibly complex
3954 jump instruction by a goto or by removing the jump completely.
3955 This can apply only if all edges now point to the same block. The
3956 parameters and return values are equivalent to
3957 redirect_edge_and_branch. */
3960 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
3962 basic_block src = e->src;
3963 block_stmt_iterator b;
3966 /* We can replace or remove a complex jump only when we have exactly
3968 if (EDGE_COUNT (src->succs) != 2
3969 /* Verify that all targets will be TARGET. Specifically, the
3970 edge that is not E must also go to TARGET. */
3971 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
3977 stmt = bsi_stmt (b);
3979 if (TREE_CODE (stmt) == COND_EXPR
3980 || TREE_CODE (stmt) == SWITCH_EXPR)
3982 bsi_remove (&b, true);
3983 e = ssa_redirect_edge (e, target);
3984 e->flags = EDGE_FALLTHRU;
3992 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3993 edge representing the redirected branch. */
3996 tree_redirect_edge_and_branch (edge e, basic_block dest)
3998 basic_block bb = e->src;
3999 block_stmt_iterator bsi;
4003 if (e->flags & EDGE_ABNORMAL)
4006 if (e->src != ENTRY_BLOCK_PTR
4007 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4010 if (e->dest == dest)
4013 bsi = bsi_last (bb);
4014 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4016 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4019 /* For COND_EXPR, we only need to redirect the edge. */
4023 /* No non-abnormal edges should lead from a non-simple goto, and
4024 simple ones should be represented implicitly. */
4029 tree cases = get_cases_for_edge (e, stmt);
4030 tree label = tree_block_label (dest);
4032 /* If we have a list of cases associated with E, then use it
4033 as it's a lot faster than walking the entire case vector. */
4036 edge e2 = find_edge (e->src, dest);
4043 CASE_LABEL (cases) = label;
4044 cases = TREE_CHAIN (cases);
4047 /* If there was already an edge in the CFG, then we need
4048 to move all the cases associated with E to E2. */
4051 tree cases2 = get_cases_for_edge (e2, stmt);
4053 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4054 TREE_CHAIN (cases2) = first;
4059 tree vec = SWITCH_LABELS (stmt);
4060 size_t i, n = TREE_VEC_LENGTH (vec);
4062 for (i = 0; i < n; i++)
4064 tree elt = TREE_VEC_ELT (vec, i);
4066 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4067 CASE_LABEL (elt) = label;
4075 bsi_remove (&bsi, true);
4076 e->flags |= EDGE_FALLTHRU;
4080 /* Otherwise it must be a fallthru edge, and we don't need to
4081 do anything besides redirecting it. */
4082 gcc_assert (e->flags & EDGE_FALLTHRU);
4086 /* Update/insert PHI nodes as necessary. */
4088 /* Now update the edges in the CFG. */
4089 e = ssa_redirect_edge (e, dest);
4094 /* Returns true if it is possible to remove edge E by redirecting
4095 it to the destination of the other edge from E->src. */
4098 tree_can_remove_branch_p (edge e)
4100 if (e->flags & EDGE_ABNORMAL)
4106 /* Simple wrapper, as we can always redirect fallthru edges. */
4109 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4111 e = tree_redirect_edge_and_branch (e, dest);
4118 /* Splits basic block BB after statement STMT (but at least after the
4119 labels). If STMT is NULL, BB is split just after the labels. */
4122 tree_split_block (basic_block bb, void *stmt)
4124 block_stmt_iterator bsi;
4125 tree_stmt_iterator tsi_tgt;
4131 new_bb = create_empty_bb (bb);
4133 /* Redirect the outgoing edges. */
4134 new_bb->succs = bb->succs;
4136 FOR_EACH_EDGE (e, ei, new_bb->succs)
4139 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4142 /* Move everything from BSI to the new basic block. */
4143 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4145 act = bsi_stmt (bsi);
4146 if (TREE_CODE (act) == LABEL_EXPR)
4159 if (bsi_end_p (bsi))
4162 /* Split the statement list - avoid re-creating new containers as this
4163 brings ugly quadratic memory consumption in the inliner.
4164 (We are still quadratic since we need to update stmt BB pointers,
4166 list = tsi_split_statement_list_before (&bsi.tsi);
4167 set_bb_stmt_list (new_bb, list);
4168 for (tsi_tgt = tsi_start (list);
4169 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4170 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4176 /* Moves basic block BB after block AFTER. */
4179 tree_move_block_after (basic_block bb, basic_block after)
4181 if (bb->prev_bb == after)
4185 link_block (bb, after);
4191 /* Return true if basic_block can be duplicated. */
4194 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4200 /* Create a duplicate of the basic block BB. NOTE: This does not
4201 preserve SSA form. */
4204 tree_duplicate_bb (basic_block bb)
4207 block_stmt_iterator bsi, bsi_tgt;
4210 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4212 /* Copy the PHI nodes. We ignore PHI node arguments here because
4213 the incoming edges have not been setup yet. */
4214 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4216 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4217 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4220 /* Keep the chain of PHI nodes in the same order so that they can be
4221 updated by ssa_redirect_edge. */
4222 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4224 bsi_tgt = bsi_start (new_bb);
4225 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4227 def_operand_p def_p;
4228 ssa_op_iter op_iter;
4232 stmt = bsi_stmt (bsi);
4233 if (TREE_CODE (stmt) == LABEL_EXPR)
4236 /* Create a new copy of STMT and duplicate STMT's virtual
4238 copy = unshare_expr (stmt);
4239 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4240 copy_virtual_operands (copy, stmt);
4241 region = lookup_stmt_eh_region (stmt);
4243 add_stmt_to_eh_region (copy, region);
4244 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4246 /* Create new names for all the definitions created by COPY and
4247 add replacement mappings for each new name. */
4248 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4249 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4256 /* Basic block BB_COPY was created by code duplication. Add phi node
4257 arguments for edges going out of BB_COPY. The blocks that were
4258 duplicated have BB_DUPLICATED set. */
4261 add_phi_args_after_copy_bb (basic_block bb_copy)
4263 basic_block bb, dest;
4266 tree phi, phi_copy, phi_next, def;
4268 bb = get_bb_original (bb_copy);
4270 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4272 if (!phi_nodes (e_copy->dest))
4275 if (e_copy->dest->flags & BB_DUPLICATED)
4276 dest = get_bb_original (e_copy->dest);
4278 dest = e_copy->dest;
4280 e = find_edge (bb, dest);
4283 /* During loop unrolling the target of the latch edge is copied.
4284 In this case we are not looking for edge to dest, but to
4285 duplicated block whose original was dest. */
4286 FOR_EACH_EDGE (e, ei, bb->succs)
4287 if ((e->dest->flags & BB_DUPLICATED)
4288 && get_bb_original (e->dest) == dest)
4291 gcc_assert (e != NULL);
4294 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4296 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4298 phi_next = PHI_CHAIN (phi);
4299 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4300 add_phi_arg (phi_copy, def, e_copy);
4305 /* Blocks in REGION_COPY array of length N_REGION were created by
4306 duplication of basic blocks. Add phi node arguments for edges
4307 going from these blocks. */
4310 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4314 for (i = 0; i < n_region; i++)
4315 region_copy[i]->flags |= BB_DUPLICATED;
4317 for (i = 0; i < n_region; i++)
4318 add_phi_args_after_copy_bb (region_copy[i]);
4320 for (i = 0; i < n_region; i++)
4321 region_copy[i]->flags &= ~BB_DUPLICATED;
4324 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4325 important exit edge EXIT. By important we mean that no SSA name defined
4326 inside region is live over the other exit edges of the region. All entry
4327 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4328 to the duplicate of the region. SSA form, dominance and loop information
4329 is updated. The new basic blocks are stored to REGION_COPY in the same
4330 order as they had in REGION, provided that REGION_COPY is not NULL.
4331 The function returns false if it is unable to copy the region,
4335 tree_duplicate_sese_region (edge entry, edge exit,
4336 basic_block *region, unsigned n_region,
4337 basic_block *region_copy)
4340 bool free_region_copy = false, copying_header = false;
4341 struct loop *loop = entry->dest->loop_father;
4343 VEC (basic_block, heap) *doms;
4345 int total_freq = 0, entry_freq = 0;
4346 gcov_type total_count = 0, entry_count = 0;
4348 if (!can_copy_bbs_p (region, n_region))
4351 /* Some sanity checking. Note that we do not check for all possible
4352 missuses of the functions. I.e. if you ask to copy something weird,
4353 it will work, but the state of structures probably will not be
4355 for (i = 0; i < n_region; i++)
4357 /* We do not handle subloops, i.e. all the blocks must belong to the
4359 if (region[i]->loop_father != loop)
4362 if (region[i] != entry->dest
4363 && region[i] == loop->header)
4367 set_loop_copy (loop, loop);
4369 /* In case the function is used for loop header copying (which is the primary
4370 use), ensure that EXIT and its copy will be new latch and entry edges. */
4371 if (loop->header == entry->dest)
4373 copying_header = true;
4374 set_loop_copy (loop, loop_outer (loop));
4376 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4379 for (i = 0; i < n_region; i++)
4380 if (region[i] != exit->src
4381 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4387 region_copy = XNEWVEC (basic_block, n_region);
4388 free_region_copy = true;
4391 gcc_assert (!need_ssa_update_p ());
4393 /* Record blocks outside the region that are dominated by something
4396 initialize_original_copy_tables ();
4398 doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region);
4400 if (entry->dest->count)
4402 total_count = entry->dest->count;
4403 entry_count = entry->count;
4404 /* Fix up corner cases, to avoid division by zero or creation of negative
4406 if (entry_count > total_count)
4407 entry_count = total_count;
4411 total_freq = entry->dest->frequency;
4412 entry_freq = EDGE_FREQUENCY (entry);
4413 /* Fix up corner cases, to avoid division by zero or creation of negative
4415 if (total_freq == 0)
4417 else if (entry_freq > total_freq)
4418 entry_freq = total_freq;
4421 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4422 split_edge_bb_loc (entry));
4425 scale_bbs_frequencies_gcov_type (region, n_region,
4426 total_count - entry_count,
4428 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4433 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4435 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4440 loop->header = exit->dest;
4441 loop->latch = exit->src;
4444 /* Redirect the entry and add the phi node arguments. */
4445 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4446 gcc_assert (redirected != NULL);
4447 flush_pending_stmts (entry);
4449 /* Concerning updating of dominators: We must recount dominators
4450 for entry block and its copy. Anything that is outside of the
4451 region, but was dominated by something inside needs recounting as
4453 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4454 VEC_safe_push (basic_block, heap, doms, get_bb_original (entry->dest));
4455 iterate_fix_dominators (CDI_DOMINATORS, doms, false);
4458 /* Add the other PHI node arguments. */
4459 add_phi_args_after_copy (region_copy, n_region);
4461 /* Update the SSA web. */
4462 update_ssa (TODO_update_ssa);
4464 if (free_region_copy)
4467 free_original_copy_tables ();
4472 DEF_VEC_P(basic_block);
4473 DEF_VEC_ALLOC_P(basic_block,heap);
4476 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4477 adding blocks when the dominator traversal reaches EXIT. This
4478 function silently assumes that ENTRY strictly dominates EXIT. */
4481 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4482 VEC(basic_block,heap) **bbs_p)
4486 for (son = first_dom_son (CDI_DOMINATORS, entry);
4488 son = next_dom_son (CDI_DOMINATORS, son))
4490 VEC_safe_push (basic_block, heap, *bbs_p, son);
4492 gather_blocks_in_sese_region (son, exit, bbs_p);
4502 bitmap vars_to_remove;
4503 htab_t new_label_map;
4507 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4508 contained in *TP and change the DECL_CONTEXT of every local
4509 variable referenced in *TP. */
4512 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4514 struct move_stmt_d *p = (struct move_stmt_d *) data;
4518 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4519 TREE_BLOCK (t) = p->block;
4521 if (OMP_DIRECTIVE_P (t)
4522 && TREE_CODE (t) != OMP_RETURN
4523 && TREE_CODE (t) != OMP_CONTINUE)
4525 /* Do not remap variables inside OMP directives. Variables
4526 referenced in clauses and directive header belong to the
4527 parent function and should not be moved into the child
4529 bool save_remap_decls_p = p->remap_decls_p;
4530 p->remap_decls_p = false;
4533 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4535 p->remap_decls_p = save_remap_decls_p;
4537 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4539 if (TREE_CODE (t) == LABEL_DECL)
4541 if (p->new_label_map)
4543 struct tree_map in, *out;
4545 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4550 DECL_CONTEXT (t) = p->to_context;
4552 else if (p->remap_decls_p)
4554 DECL_CONTEXT (t) = p->to_context;
4556 if (TREE_CODE (t) == VAR_DECL)
4558 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4559 f->unexpanded_var_list
4560 = tree_cons (0, t, f->unexpanded_var_list);
4562 /* Mark T to be removed from the original function,
4563 otherwise it will be given a DECL_RTL when the
4564 original function is expanded. */
4565 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4569 else if (TYPE_P (t))
4576 /* Move basic block BB from function CFUN to function DEST_FN. The
4577 block is moved out of the original linked list and placed after
4578 block AFTER in the new list. Also, the block is removed from the
4579 original array of blocks and placed in DEST_FN's array of blocks.
4580 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4581 updated to reflect the moved edges.
4583 On exit, local variables that need to be removed from
4584 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4587 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4588 basic_block after, bool update_edge_count_p,
4589 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4591 struct control_flow_graph *cfg;
4594 block_stmt_iterator si;
4595 struct move_stmt_d d;
4596 unsigned old_len, new_len;
4598 /* Remove BB from dominance structures. */
4599 delete_from_dominance_info (CDI_DOMINATORS, bb);
4601 /* Link BB to the new linked list. */
4602 move_block_after (bb, after);
4604 /* Update the edge count in the corresponding flowgraphs. */
4605 if (update_edge_count_p)
4606 FOR_EACH_EDGE (e, ei, bb->succs)
4608 cfun->cfg->x_n_edges--;
4609 dest_cfun->cfg->x_n_edges++;
4612 /* Remove BB from the original basic block array. */
4613 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4614 cfun->cfg->x_n_basic_blocks--;
4616 /* Grow DEST_CFUN's basic block array if needed. */
4617 cfg = dest_cfun->cfg;
4618 cfg->x_n_basic_blocks++;
4619 if (bb->index >= cfg->x_last_basic_block)
4620 cfg->x_last_basic_block = bb->index + 1;
4622 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4623 if ((unsigned) cfg->x_last_basic_block >= old_len)
4625 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4626 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4630 VEC_replace (basic_block, cfg->x_basic_block_info,
4633 /* The statements in BB need to be associated with a new TREE_BLOCK.
4634 Labels need to be associated with a new label-to-block map. */
4635 memset (&d, 0, sizeof (d));
4636 d.vars_to_remove = vars_to_remove;
4638 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4640 tree stmt = bsi_stmt (si);
4643 d.from_context = cfun->decl;
4644 d.to_context = dest_cfun->decl;
4645 d.remap_decls_p = true;
4646 d.new_label_map = new_label_map;
4647 if (TREE_BLOCK (stmt))
4648 d.block = DECL_INITIAL (dest_cfun->decl);
4650 walk_tree (&stmt, move_stmt_r, &d, NULL);
4652 if (TREE_CODE (stmt) == LABEL_EXPR)
4654 tree label = LABEL_EXPR_LABEL (stmt);
4655 int uid = LABEL_DECL_UID (label);
4657 gcc_assert (uid > -1);
4659 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4660 if (old_len <= (unsigned) uid)
4662 new_len = 3 * uid / 2;
4663 VEC_safe_grow_cleared (basic_block, gc,
4664 cfg->x_label_to_block_map, new_len);
4667 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4668 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4670 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4672 if (uid >= dest_cfun->last_label_uid)
4673 dest_cfun->last_label_uid = uid + 1;
4675 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4676 TREE_OPERAND (stmt, 0) =
4677 build_int_cst (NULL_TREE,
4678 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4681 region = lookup_stmt_eh_region (stmt);
4684 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4685 remove_stmt_from_eh_region (stmt);
4686 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4687 gimple_remove_stmt_histograms (cfun, stmt);
4692 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4693 the outermost EH region. Use REGION as the incoming base EH region. */
4696 find_outermost_region_in_block (struct function *src_cfun,
4697 basic_block bb, int region)
4699 block_stmt_iterator si;
4701 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4703 tree stmt = bsi_stmt (si);
4706 if (TREE_CODE (stmt) == RESX_EXPR)
4707 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4709 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4710 if (stmt_region > 0)
4713 region = stmt_region;
4714 else if (stmt_region != region)
4716 region = eh_region_outermost (src_cfun, stmt_region, region);
4717 gcc_assert (region != -1);
4726 new_label_mapper (tree decl, void *data)
4728 htab_t hash = (htab_t) data;
4732 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4734 m = xmalloc (sizeof (struct tree_map));
4735 m->hash = DECL_UID (decl);
4736 m->base.from = decl;
4737 m->to = create_artificial_label ();
4738 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4740 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4741 gcc_assert (*slot == NULL);
4748 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4749 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4750 single basic block in the original CFG and the new basic block is
4751 returned. DEST_CFUN must not have a CFG yet.
4753 Note that the region need not be a pure SESE region. Blocks inside
4754 the region may contain calls to abort/exit. The only restriction
4755 is that ENTRY_BB should be the only entry point and it must
4758 All local variables referenced in the region are assumed to be in
4759 the corresponding BLOCK_VARS and unexpanded variable lists
4760 associated with DEST_CFUN. */
4763 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4764 basic_block exit_bb)
4766 VEC(basic_block,heap) *bbs;
4767 basic_block after, bb, *entry_pred, *exit_succ;
4768 struct function *saved_cfun;
4769 int *entry_flag, *exit_flag, eh_offset;
4770 unsigned i, num_entry_edges, num_exit_edges;
4773 bitmap vars_to_remove;
4774 htab_t new_label_map;
4778 /* Collect all the blocks in the region. Manually add ENTRY_BB
4779 because it won't be added by dfs_enumerate_from. */
4780 calculate_dominance_info (CDI_DOMINATORS);
4782 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4784 gcc_assert (entry_bb != exit_bb
4786 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4789 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4790 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4792 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4793 the predecessor edges to ENTRY_BB and the successor edges to
4794 EXIT_BB so that we can re-attach them to the new basic block that
4795 will replace the region. */
4796 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4797 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4798 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4800 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4802 entry_flag[i] = e->flags;
4803 entry_pred[i++] = e->src;
4809 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4810 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4811 sizeof (basic_block));
4812 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4814 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4816 exit_flag[i] = e->flags;
4817 exit_succ[i++] = e->dest;
4828 /* Switch context to the child function to initialize DEST_FN's CFG. */
4829 gcc_assert (dest_cfun->cfg == NULL);
4832 init_empty_tree_cfg ();
4834 /* Initialize EH information for the new function. */
4836 new_label_map = NULL;
4841 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4842 region = find_outermost_region_in_block (saved_cfun, bb, region);
4844 init_eh_for_function ();
4847 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4848 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4849 new_label_map, region, 0);
4855 /* Move blocks from BBS into DEST_CFUN. */
4856 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4857 after = dest_cfun->cfg->x_entry_block_ptr;
4858 vars_to_remove = BITMAP_ALLOC (NULL);
4859 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4861 /* No need to update edge counts on the last block. It has
4862 already been updated earlier when we detached the region from
4863 the original CFG. */
4864 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4865 new_label_map, eh_offset);
4870 htab_delete (new_label_map);
4872 /* Remove the variables marked in VARS_TO_REMOVE from
4873 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4874 DECL_RTL in the context of CFUN. */
4875 if (!bitmap_empty_p (vars_to_remove))
4879 for (p = &cfun->unexpanded_var_list; *p; )
4881 tree var = TREE_VALUE (*p);
4882 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4884 *p = TREE_CHAIN (*p);
4888 p = &TREE_CHAIN (*p);
4892 BITMAP_FREE (vars_to_remove);
4894 /* Rewire the entry and exit blocks. The successor to the entry
4895 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4896 the child function. Similarly, the predecessor of DEST_FN's
4897 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4898 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4899 various CFG manipulation function get to the right CFG.
4901 FIXME, this is silly. The CFG ought to become a parameter to
4904 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4906 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4909 /* Back in the original function, the SESE region has disappeared,
4910 create a new basic block in its place. */
4911 bb = create_empty_bb (entry_pred[0]);
4912 for (i = 0; i < num_entry_edges; i++)
4913 make_edge (entry_pred[i], bb, entry_flag[i]);
4915 for (i = 0; i < num_exit_edges; i++)
4916 make_edge (bb, exit_succ[i], exit_flag[i]);
4925 free_dominance_info (CDI_DOMINATORS);
4926 free_dominance_info (CDI_POST_DOMINATORS);
4927 VEC_free (basic_block, heap, bbs);
4933 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4936 dump_function_to_file (tree fn, FILE *file, int flags)
4938 tree arg, vars, var;
4939 struct function *dsf;
4940 bool ignore_topmost_bind = false, any_var = false;
4943 struct function *saved_cfun;
4945 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
4947 arg = DECL_ARGUMENTS (fn);
4950 print_generic_expr (file, arg, dump_flags);
4951 if (TREE_CHAIN (arg))
4952 fprintf (file, ", ");
4953 arg = TREE_CHAIN (arg);
4955 fprintf (file, ")\n");
4957 dsf = DECL_STRUCT_FUNCTION (fn);
4958 if (dsf && (flags & TDF_DETAILS))
4959 dump_eh_tree (file, dsf);
4961 if (flags & TDF_RAW)
4963 dump_node (fn, TDF_SLIM | flags, file);
4967 /* Switch CFUN to point to FN. */
4969 cfun = DECL_STRUCT_FUNCTION (fn);
4971 /* When GIMPLE is lowered, the variables are no longer available in
4972 BIND_EXPRs, so display them separately. */
4973 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
4975 ignore_topmost_bind = true;
4977 fprintf (file, "{\n");
4978 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
4980 var = TREE_VALUE (vars);
4982 print_generic_decl (file, var, flags);
4983 fprintf (file, "\n");
4989 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
4991 /* Make a CFG based dump. */
4992 check_bb_profile (ENTRY_BLOCK_PTR, file);
4993 if (!ignore_topmost_bind)
4994 fprintf (file, "{\n");
4996 if (any_var && n_basic_blocks)
4997 fprintf (file, "\n");
5000 dump_generic_bb (file, bb, 2, flags);
5002 fprintf (file, "}\n");
5003 check_bb_profile (EXIT_BLOCK_PTR, file);
5009 /* Make a tree based dump. */
5010 chain = DECL_SAVED_TREE (fn);
5012 if (chain && TREE_CODE (chain) == BIND_EXPR)
5014 if (ignore_topmost_bind)
5016 chain = BIND_EXPR_BODY (chain);
5024 if (!ignore_topmost_bind)
5025 fprintf (file, "{\n");
5030 fprintf (file, "\n");
5032 print_generic_stmt_indented (file, chain, flags, indent);
5033 if (ignore_topmost_bind)
5034 fprintf (file, "}\n");
5037 fprintf (file, "\n\n");
5044 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5047 debug_function (tree fn, int flags)
5049 dump_function_to_file (fn, stderr, flags);
5053 /* Pretty print of the loops intermediate representation. */
5054 static void print_loop (FILE *, struct loop *, int);
5055 static void print_pred_bbs (FILE *, basic_block bb);
5056 static void print_succ_bbs (FILE *, basic_block bb);
5059 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5062 print_pred_bbs (FILE *file, basic_block bb)
5067 FOR_EACH_EDGE (e, ei, bb->preds)
5068 fprintf (file, "bb_%d ", e->src->index);
5072 /* Print on FILE the indexes for the successors of basic_block BB. */
5075 print_succ_bbs (FILE *file, basic_block bb)
5080 FOR_EACH_EDGE (e, ei, bb->succs)
5081 fprintf (file, "bb_%d ", e->dest->index);
5085 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5088 print_loop (FILE *file, struct loop *loop, int indent)
5096 s_indent = (char *) alloca ((size_t) indent + 1);
5097 memset ((void *) s_indent, ' ', (size_t) indent);
5098 s_indent[indent] = '\0';
5100 /* Print the loop's header. */
5101 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5103 /* Print the loop's body. */
5104 fprintf (file, "%s{\n", s_indent);
5106 if (bb->loop_father == loop)
5108 /* Print the basic_block's header. */
5109 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5110 print_pred_bbs (file, bb);
5111 fprintf (file, "}, succs = {");
5112 print_succ_bbs (file, bb);
5113 fprintf (file, "})\n");
5115 /* Print the basic_block's body. */
5116 fprintf (file, "%s {\n", s_indent);
5117 tree_dump_bb (bb, file, indent + 4);
5118 fprintf (file, "%s }\n", s_indent);
5121 print_loop (file, loop->inner, indent + 2);
5122 fprintf (file, "%s}\n", s_indent);
5123 print_loop (file, loop->next, indent);
5127 /* Follow a CFG edge from the entry point of the program, and on entry
5128 of a loop, pretty print the loop structure on FILE. */
5131 print_loop_ir (FILE *file)
5135 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5136 if (bb && bb->loop_father)
5137 print_loop (file, bb->loop_father, 0);
5141 /* Debugging loops structure at tree level. */
5144 debug_loop_ir (void)
5146 print_loop_ir (stderr);
5150 /* Return true if BB ends with a call, possibly followed by some
5151 instructions that must stay with the call. Return false,
5155 tree_block_ends_with_call_p (basic_block bb)
5157 block_stmt_iterator bsi = bsi_last (bb);
5158 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5162 /* Return true if BB ends with a conditional branch. Return false,
5166 tree_block_ends_with_condjump_p (basic_block bb)
5168 tree stmt = last_stmt (bb);
5169 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5173 /* Return true if we need to add fake edge to exit at statement T.
5174 Helper function for tree_flow_call_edges_add. */
5177 need_fake_edge_p (tree t)
5181 /* NORETURN and LONGJMP calls already have an edge to exit.
5182 CONST and PURE calls do not need one.
5183 We don't currently check for CONST and PURE here, although
5184 it would be a good idea, because those attributes are
5185 figured out from the RTL in mark_constant_function, and
5186 the counter incrementation code from -fprofile-arcs
5187 leads to different results from -fbranch-probabilities. */
5188 call = get_call_expr_in (t);
5190 && !(call_expr_flags (call) & ECF_NORETURN))
5193 if (TREE_CODE (t) == ASM_EXPR
5194 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5201 /* Add fake edges to the function exit for any non constant and non
5202 noreturn calls, volatile inline assembly in the bitmap of blocks
5203 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5204 the number of blocks that were split.
5206 The goal is to expose cases in which entering a basic block does
5207 not imply that all subsequent instructions must be executed. */
5210 tree_flow_call_edges_add (sbitmap blocks)
5213 int blocks_split = 0;
5214 int last_bb = last_basic_block;
5215 bool check_last_block = false;
5217 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5221 check_last_block = true;
5223 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5225 /* In the last basic block, before epilogue generation, there will be
5226 a fallthru edge to EXIT. Special care is required if the last insn
5227 of the last basic block is a call because make_edge folds duplicate
5228 edges, which would result in the fallthru edge also being marked
5229 fake, which would result in the fallthru edge being removed by
5230 remove_fake_edges, which would result in an invalid CFG.
5232 Moreover, we can't elide the outgoing fake edge, since the block
5233 profiler needs to take this into account in order to solve the minimal
5234 spanning tree in the case that the call doesn't return.
5236 Handle this by adding a dummy instruction in a new last basic block. */
5237 if (check_last_block)
5239 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5240 block_stmt_iterator bsi = bsi_last (bb);
5242 if (!bsi_end_p (bsi))
5245 if (t && need_fake_edge_p (t))
5249 e = find_edge (bb, EXIT_BLOCK_PTR);
5252 bsi_insert_on_edge (e, build_empty_stmt ());
5253 bsi_commit_edge_inserts ();
5258 /* Now add fake edges to the function exit for any non constant
5259 calls since there is no way that we can determine if they will
5261 for (i = 0; i < last_bb; i++)
5263 basic_block bb = BASIC_BLOCK (i);
5264 block_stmt_iterator bsi;
5265 tree stmt, last_stmt;
5270 if (blocks && !TEST_BIT (blocks, i))
5273 bsi = bsi_last (bb);
5274 if (!bsi_end_p (bsi))
5276 last_stmt = bsi_stmt (bsi);
5279 stmt = bsi_stmt (bsi);
5280 if (need_fake_edge_p (stmt))
5283 /* The handling above of the final block before the
5284 epilogue should be enough to verify that there is
5285 no edge to the exit block in CFG already.
5286 Calling make_edge in such case would cause us to
5287 mark that edge as fake and remove it later. */
5288 #ifdef ENABLE_CHECKING
5289 if (stmt == last_stmt)
5291 e = find_edge (bb, EXIT_BLOCK_PTR);
5292 gcc_assert (e == NULL);
5296 /* Note that the following may create a new basic block
5297 and renumber the existing basic blocks. */
5298 if (stmt != last_stmt)
5300 e = split_block (bb, stmt);
5304 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5308 while (!bsi_end_p (bsi));
5313 verify_flow_info ();
5315 return blocks_split;
5318 /* Purge dead abnormal call edges from basic block BB. */
5321 tree_purge_dead_abnormal_call_edges (basic_block bb)
5323 bool changed = tree_purge_dead_eh_edges (bb);
5325 if (current_function_has_nonlocal_label)
5327 tree stmt = last_stmt (bb);
5331 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5332 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5334 if (e->flags & EDGE_ABNORMAL)
5343 /* See tree_purge_dead_eh_edges below. */
5345 free_dominance_info (CDI_DOMINATORS);
5351 /* Stores all basic blocks dominated by BB to DOM_BBS. */
5354 get_all_dominated_blocks (basic_block bb, VEC (basic_block, heap) **dom_bbs)
5358 VEC_safe_push (basic_block, heap, *dom_bbs, bb);
5359 for (son = first_dom_son (CDI_DOMINATORS, bb);
5361 son = next_dom_son (CDI_DOMINATORS, son))
5362 get_all_dominated_blocks (son, dom_bbs);
5365 /* Removes edge E and all the blocks dominated by it, and updates dominance
5366 information. The IL in E->src needs to be updated separately.
5367 If dominance info is not available, only the edge E is removed.*/
5370 remove_edge_and_dominated_blocks (edge e)
5372 VEC (basic_block, heap) *bbs_to_remove = NULL;
5373 VEC (basic_block, heap) *bbs_to_fix_dom = NULL;
5377 bool none_removed = false;
5379 basic_block bb, dbb;
5382 if (!dom_info_available_p (CDI_DOMINATORS))
5388 /* No updating is needed for edges to exit. */
5389 if (e->dest == EXIT_BLOCK_PTR)
5391 if (cfgcleanup_altered_bbs)
5392 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5397 /* First, we find the basic blocks to remove. If E->dest has a predecessor
5398 that is not dominated by E->dest, then this set is empty. Otherwise,
5399 all the basic blocks dominated by E->dest are removed.
5401 Also, to DF_IDOM we store the immediate dominators of the blocks in
5402 the dominance frontier of E (i.e., of the successors of the
5403 removed blocks, if there are any, and of E->dest otherwise). */
5404 FOR_EACH_EDGE (f, ei, e->dest->preds)
5409 if (!dominated_by_p (CDI_DOMINATORS, f->src, e->dest))
5411 none_removed = true;
5416 df = BITMAP_ALLOC (NULL);
5417 df_idom = BITMAP_ALLOC (NULL);
5420 bitmap_set_bit (df_idom,
5421 get_immediate_dominator (CDI_DOMINATORS, e->dest)->index);
5424 get_all_dominated_blocks (e->dest, &bbs_to_remove);
5425 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5427 FOR_EACH_EDGE (f, ei, bb->succs)
5429 if (f->dest != EXIT_BLOCK_PTR)
5430 bitmap_set_bit (df, f->dest->index);
5433 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5434 bitmap_clear_bit (df, bb->index);
5436 EXECUTE_IF_SET_IN_BITMAP (df, 0, i, bi)
5438 bb = BASIC_BLOCK (i);
5439 bitmap_set_bit (df_idom,
5440 get_immediate_dominator (CDI_DOMINATORS, bb)->index);
5444 if (cfgcleanup_altered_bbs)
5446 /* Record the set of the altered basic blocks. */
5447 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5448 bitmap_ior_into (cfgcleanup_altered_bbs, df);
5451 /* Remove E and the cancelled blocks. */
5456 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5457 delete_basic_block (bb);
5460 /* Update the dominance information. The immediate dominator may change only
5461 for blocks whose immediate dominator belongs to DF_IDOM:
5463 Suppose that idom(X) = Y before removal of E and idom(X) != Y after the
5464 removal. Let Z the arbitrary block such that idom(Z) = Y and
5465 Z dominates X after the removal. Before removal, there exists a path P
5466 from Y to X that avoids Z. Let F be the last edge on P that is
5467 removed, and let W = F->dest. Before removal, idom(W) = Y (since Y
5468 dominates W, and because of P, Z does not dominate W), and W belongs to
5469 the dominance frontier of E. Therefore, Y belongs to DF_IDOM. */
5470 EXECUTE_IF_SET_IN_BITMAP (df_idom, 0, i, bi)
5472 bb = BASIC_BLOCK (i);
5473 for (dbb = first_dom_son (CDI_DOMINATORS, bb);
5475 dbb = next_dom_son (CDI_DOMINATORS, dbb))
5476 VEC_safe_push (basic_block, heap, bbs_to_fix_dom, dbb);
5479 iterate_fix_dominators (CDI_DOMINATORS, bbs_to_fix_dom, true);
5482 BITMAP_FREE (df_idom);
5483 VEC_free (basic_block, heap, bbs_to_remove);
5484 VEC_free (basic_block, heap, bbs_to_fix_dom);
5487 /* Purge dead EH edges from basic block BB. */
5490 tree_purge_dead_eh_edges (basic_block bb)
5492 bool changed = false;
5495 tree stmt = last_stmt (bb);
5497 if (stmt && tree_can_throw_internal (stmt))
5500 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5502 if (e->flags & EDGE_EH)
5504 remove_edge_and_dominated_blocks (e);
5515 tree_purge_all_dead_eh_edges (bitmap blocks)
5517 bool changed = false;
5521 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5523 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5529 /* This function is called whenever a new edge is created or
5533 tree_execute_on_growing_pred (edge e)
5535 basic_block bb = e->dest;
5538 reserve_phi_args_for_new_edge (bb);
5541 /* This function is called immediately before edge E is removed from
5542 the edge vector E->dest->preds. */
5545 tree_execute_on_shrinking_pred (edge e)
5547 if (phi_nodes (e->dest))
5548 remove_phi_args (e);
5551 /*---------------------------------------------------------------------------
5552 Helper functions for Loop versioning
5553 ---------------------------------------------------------------------------*/
5555 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5556 of 'first'. Both of them are dominated by 'new_head' basic block. When
5557 'new_head' was created by 'second's incoming edge it received phi arguments
5558 on the edge by split_edge(). Later, additional edge 'e' was created to
5559 connect 'new_head' and 'first'. Now this routine adds phi args on this
5560 additional edge 'e' that new_head to second edge received as part of edge
5565 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5566 basic_block new_head, edge e)
5569 edge e2 = find_edge (new_head, second);
5571 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5572 edge, we should always have an edge from NEW_HEAD to SECOND. */
5573 gcc_assert (e2 != NULL);
5575 /* Browse all 'second' basic block phi nodes and add phi args to
5576 edge 'e' for 'first' head. PHI args are always in correct order. */
5578 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5580 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5582 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5583 add_phi_arg (phi1, def, e);
5587 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5588 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5589 the destination of the ELSE part. */
5591 tree_lv_add_condition_to_bb (basic_block first_head ATTRIBUTE_UNUSED,
5592 basic_block second_head ATTRIBUTE_UNUSED,
5593 basic_block cond_bb, void *cond_e)
5595 block_stmt_iterator bsi;
5596 tree new_cond_expr = NULL_TREE;
5597 tree cond_expr = (tree) cond_e;
5600 /* Build new conditional expr */
5601 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr,
5602 NULL_TREE, NULL_TREE);
5604 /* Add new cond in cond_bb. */
5605 bsi = bsi_start (cond_bb);
5606 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5607 /* Adjust edges appropriately to connect new head with first head
5608 as well as second head. */
5609 e0 = single_succ_edge (cond_bb);
5610 e0->flags &= ~EDGE_FALLTHRU;
5611 e0->flags |= EDGE_FALSE_VALUE;
5614 struct cfg_hooks tree_cfg_hooks = {
5616 tree_verify_flow_info,
5617 tree_dump_bb, /* dump_bb */
5618 create_bb, /* create_basic_block */
5619 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5620 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5621 tree_can_remove_branch_p, /* can_remove_branch_p */
5622 remove_bb, /* delete_basic_block */
5623 tree_split_block, /* split_block */
5624 tree_move_block_after, /* move_block_after */
5625 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5626 tree_merge_blocks, /* merge_blocks */
5627 tree_predict_edge, /* predict_edge */
5628 tree_predicted_by_p, /* predicted_by_p */
5629 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5630 tree_duplicate_bb, /* duplicate_block */
5631 tree_split_edge, /* split_edge */
5632 tree_make_forwarder_block, /* make_forward_block */
5633 NULL, /* tidy_fallthru_edge */
5634 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5635 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5636 tree_flow_call_edges_add, /* flow_call_edges_add */
5637 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5638 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5639 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5640 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5641 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5642 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5643 flush_pending_stmts /* flush_pending_stmts */
5647 /* Split all critical edges. */
5650 split_critical_edges (void)
5656 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5657 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5658 mappings around the calls to split_edge. */
5659 start_recording_case_labels ();
5662 FOR_EACH_EDGE (e, ei, bb->succs)
5663 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5668 end_recording_case_labels ();
5672 struct tree_opt_pass pass_split_crit_edges =
5674 "crited", /* name */
5676 split_critical_edges, /* execute */
5679 0, /* static_pass_number */
5680 TV_TREE_SPLIT_EDGES, /* tv_id */
5681 PROP_cfg, /* properties required */
5682 PROP_no_crit_edges, /* properties_provided */
5683 0, /* properties_destroyed */
5684 0, /* todo_flags_start */
5685 TODO_dump_func, /* todo_flags_finish */
5690 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5691 a temporary, make sure and register it to be renamed if necessary,
5692 and finally return the temporary. Put the statements to compute
5693 EXP before the current statement in BSI. */
5696 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5698 tree t, new_stmt, orig_stmt;
5700 if (is_gimple_val (exp))
5703 t = make_rename_temp (type, NULL);
5704 new_stmt = build_gimple_modify_stmt (t, exp);
5706 orig_stmt = bsi_stmt (*bsi);
5707 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5708 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5710 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5711 if (gimple_in_ssa_p (cfun))
5712 mark_symbols_for_renaming (new_stmt);
5717 /* Build a ternary operation and gimplify it. Emit code before BSI.
5718 Return the gimple_val holding the result. */
5721 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5722 tree type, tree a, tree b, tree c)
5726 ret = fold_build3 (code, type, a, b, c);
5729 return gimplify_val (bsi, type, ret);
5732 /* Build a binary operation and gimplify it. Emit code before BSI.
5733 Return the gimple_val holding the result. */
5736 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5737 tree type, tree a, tree b)
5741 ret = fold_build2 (code, type, a, b);
5744 return gimplify_val (bsi, type, ret);
5747 /* Build a unary operation and gimplify it. Emit code before BSI.
5748 Return the gimple_val holding the result. */
5751 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5756 ret = fold_build1 (code, type, a);
5759 return gimplify_val (bsi, type, ret);
5764 /* Emit return warnings. */
5767 execute_warn_function_return (void)
5769 #ifdef USE_MAPPED_LOCATION
5770 source_location location;
5778 /* If we have a path to EXIT, then we do return. */
5779 if (TREE_THIS_VOLATILE (cfun->decl)
5780 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5782 #ifdef USE_MAPPED_LOCATION
5783 location = UNKNOWN_LOCATION;
5787 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5789 last = last_stmt (e->src);
5790 if (TREE_CODE (last) == RETURN_EXPR
5791 #ifdef USE_MAPPED_LOCATION
5792 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5794 && (locus = EXPR_LOCUS (last)) != NULL)
5798 #ifdef USE_MAPPED_LOCATION
5799 if (location == UNKNOWN_LOCATION)
5800 location = cfun->function_end_locus;
5801 warning (0, "%H%<noreturn%> function does return", &location);
5804 locus = &cfun->function_end_locus;
5805 warning (0, "%H%<noreturn%> function does return", locus);
5809 /* If we see "return;" in some basic block, then we do reach the end
5810 without returning a value. */
5811 else if (warn_return_type
5812 && !TREE_NO_WARNING (cfun->decl)
5813 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5814 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5816 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5818 tree last = last_stmt (e->src);
5819 if (TREE_CODE (last) == RETURN_EXPR
5820 && TREE_OPERAND (last, 0) == NULL
5821 && !TREE_NO_WARNING (last))
5823 #ifdef USE_MAPPED_LOCATION
5824 location = EXPR_LOCATION (last);
5825 if (location == UNKNOWN_LOCATION)
5826 location = cfun->function_end_locus;
5827 warning (0, "%Hcontrol reaches end of non-void function", &location);
5829 locus = EXPR_LOCUS (last);
5831 locus = &cfun->function_end_locus;
5832 warning (0, "%Hcontrol reaches end of non-void function", locus);
5834 TREE_NO_WARNING (cfun->decl) = 1;
5843 /* Given a basic block B which ends with a conditional and has
5844 precisely two successors, determine which of the edges is taken if
5845 the conditional is true and which is taken if the conditional is
5846 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5849 extract_true_false_edges_from_block (basic_block b,
5853 edge e = EDGE_SUCC (b, 0);
5855 if (e->flags & EDGE_TRUE_VALUE)
5858 *false_edge = EDGE_SUCC (b, 1);
5863 *true_edge = EDGE_SUCC (b, 1);
5867 struct tree_opt_pass pass_warn_function_return =
5871 execute_warn_function_return, /* execute */
5874 0, /* static_pass_number */
5876 PROP_cfg, /* properties_required */
5877 0, /* properties_provided */
5878 0, /* properties_destroyed */
5879 0, /* todo_flags_start */
5880 0, /* todo_flags_finish */
5884 /* Emit noreturn warnings. */
5887 execute_warn_function_noreturn (void)
5889 if (warn_missing_noreturn
5890 && !TREE_THIS_VOLATILE (cfun->decl)
5891 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5892 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5893 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5894 "for attribute %<noreturn%>",
5899 struct tree_opt_pass pass_warn_function_noreturn =
5903 execute_warn_function_noreturn, /* execute */
5906 0, /* static_pass_number */
5908 PROP_cfg, /* properties_required */
5909 0, /* properties_provided */
5910 0, /* properties_destroyed */
5911 0, /* todo_flags_start */
5912 0, /* todo_flags_finish */