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. */
185 /* Debugging dumps. */
187 /* Write the flowgraph to a VCG file. */
189 int local_dump_flags;
190 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
193 tree_cfg2vcg (vcg_file);
194 dump_end (TDI_vcg, vcg_file);
198 #ifdef ENABLE_CHECKING
202 /* Dump a textual representation of the flowgraph. */
204 dump_tree_cfg (dump_file, dump_flags);
208 execute_build_cfg (void)
210 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
214 struct tree_opt_pass pass_build_cfg =
218 execute_build_cfg, /* execute */
221 0, /* static_pass_number */
222 TV_TREE_CFG, /* tv_id */
223 PROP_gimple_leh, /* properties_required */
224 PROP_cfg, /* properties_provided */
225 0, /* properties_destroyed */
226 0, /* todo_flags_start */
227 TODO_verify_stmts | TODO_cleanup_cfg, /* todo_flags_finish */
231 /* Search the CFG for any computed gotos. If found, factor them to a
232 common computed goto site. Also record the location of that site so
233 that we can un-factor the gotos after we have converted back to
237 factor_computed_gotos (void)
240 tree factored_label_decl = NULL;
242 tree factored_computed_goto_label = NULL;
243 tree factored_computed_goto = NULL;
245 /* We know there are one or more computed gotos in this function.
246 Examine the last statement in each basic block to see if the block
247 ends with a computed goto. */
251 block_stmt_iterator bsi = bsi_last (bb);
256 last = bsi_stmt (bsi);
258 /* Ignore the computed goto we create when we factor the original
260 if (last == factored_computed_goto)
263 /* If the last statement is a computed goto, factor it. */
264 if (computed_goto_p (last))
268 /* The first time we find a computed goto we need to create
269 the factored goto block and the variable each original
270 computed goto will use for their goto destination. */
271 if (! factored_computed_goto)
273 basic_block new_bb = create_empty_bb (bb);
274 block_stmt_iterator new_bsi = bsi_start (new_bb);
276 /* Create the destination of the factored goto. Each original
277 computed goto will put its desired destination into this
278 variable and jump to the label we create immediately
280 var = create_tmp_var (ptr_type_node, "gotovar");
282 /* Build a label for the new block which will contain the
283 factored computed goto. */
284 factored_label_decl = create_artificial_label ();
285 factored_computed_goto_label
286 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
287 bsi_insert_after (&new_bsi, factored_computed_goto_label,
290 /* Build our new computed goto. */
291 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
292 bsi_insert_after (&new_bsi, factored_computed_goto,
296 /* Copy the original computed goto's destination into VAR. */
297 assignment = build_gimple_modify_stmt (var,
298 GOTO_DESTINATION (last));
299 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
301 /* And re-vector the computed goto to the new destination. */
302 GOTO_DESTINATION (last) = factored_label_decl;
308 /* Build a flowgraph for the statement_list STMT_LIST. */
311 make_blocks (tree stmt_list)
313 tree_stmt_iterator i = tsi_start (stmt_list);
315 bool start_new_block = true;
316 bool first_stmt_of_list = true;
317 basic_block bb = ENTRY_BLOCK_PTR;
319 while (!tsi_end_p (i))
326 /* If the statement starts a new basic block or if we have determined
327 in a previous pass that we need to create a new block for STMT, do
329 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
331 if (!first_stmt_of_list)
332 stmt_list = tsi_split_statement_list_before (&i);
333 bb = create_basic_block (stmt_list, NULL, bb);
334 start_new_block = false;
337 /* Now add STMT to BB and create the subgraphs for special statement
339 set_bb_for_stmt (stmt, bb);
341 if (computed_goto_p (stmt))
342 found_computed_goto = true;
344 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
346 if (stmt_ends_bb_p (stmt))
347 start_new_block = true;
350 first_stmt_of_list = false;
355 /* Create and return a new empty basic block after bb AFTER. */
358 create_bb (void *h, void *e, basic_block after)
364 /* Create and initialize a new basic block. Since alloc_block uses
365 ggc_alloc_cleared to allocate a basic block, we do not have to
366 clear the newly allocated basic block here. */
369 bb->index = last_basic_block;
371 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
373 /* Add the new block to the linked list of blocks. */
374 link_block (bb, after);
376 /* Grow the basic block array if needed. */
377 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
379 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
380 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
383 /* Add the newly created block to the array. */
384 SET_BASIC_BLOCK (last_basic_block, bb);
393 /*---------------------------------------------------------------------------
395 ---------------------------------------------------------------------------*/
397 /* Fold COND_EXPR_COND of each COND_EXPR. */
400 fold_cond_expr_cond (void)
406 tree stmt = last_stmt (bb);
409 && TREE_CODE (stmt) == COND_EXPR)
414 fold_defer_overflow_warnings ();
415 cond = fold (COND_EXPR_COND (stmt));
416 zerop = integer_zerop (cond);
417 onep = integer_onep (cond);
418 fold_undefer_overflow_warnings (zerop || onep, stmt,
419 WARN_STRICT_OVERFLOW_CONDITIONAL);
421 COND_EXPR_COND (stmt) = boolean_false_node;
423 COND_EXPR_COND (stmt) = boolean_true_node;
428 /* Join all the blocks in the flowgraph. */
434 struct omp_region *cur_region = NULL;
436 /* Create an edge from entry to the first block with executable
438 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
440 /* Traverse the basic block array placing edges. */
443 tree last = last_stmt (bb);
448 enum tree_code code = TREE_CODE (last);
452 make_goto_expr_edges (bb);
456 make_edge (bb, EXIT_BLOCK_PTR, 0);
460 make_cond_expr_edges (bb);
464 make_switch_expr_edges (bb);
468 make_eh_edges (last);
473 /* If this function receives a nonlocal goto, then we need to
474 make edges from this call site to all the nonlocal goto
476 if (tree_can_make_abnormal_goto (last))
477 make_abnormal_goto_edges (bb, true);
479 /* If this statement has reachable exception handlers, then
480 create abnormal edges to them. */
481 make_eh_edges (last);
483 /* Some calls are known not to return. */
484 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
490 case GIMPLE_MODIFY_STMT:
491 if (is_ctrl_altering_stmt (last))
493 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
494 the CALL_EXPR may have an abnormal edge. Search the RHS
495 for this case and create any required edges. */
496 if (tree_can_make_abnormal_goto (last))
497 make_abnormal_goto_edges (bb, true);
499 make_eh_edges (last);
511 cur_region = new_omp_region (bb, code, cur_region);
516 cur_region = new_omp_region (bb, code, cur_region);
521 /* In the case of an OMP_SECTION, the edge will go somewhere
522 other than the next block. This will be created later. */
523 cur_region->exit = bb;
524 fallthru = cur_region->type != OMP_SECTION;
525 cur_region = cur_region->outer;
529 cur_region->cont = bb;
530 switch (cur_region->type)
533 /* ??? Technically there should be a some sort of loopback
534 edge here, but it goes to a block that doesn't exist yet,
535 and without it, updating the ssa form would be a real
536 bear. Fortunately, we don't yet do ssa before expanding
541 /* Wire up the edges into and out of the nested sections. */
542 /* ??? Similarly wrt loopback. */
544 struct omp_region *i;
545 for (i = cur_region->inner; i ; i = i->next)
547 gcc_assert (i->type == OMP_SECTION);
548 make_edge (cur_region->entry, i->entry, 0);
549 make_edge (i->exit, bb, EDGE_FALLTHRU);
561 gcc_assert (!stmt_ends_bb_p (last));
569 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
575 /* Fold COND_EXPR_COND of each COND_EXPR. */
576 fold_cond_expr_cond ();
580 /* Create the edges for a COND_EXPR starting at block BB.
581 At this point, both clauses must contain only simple gotos. */
584 make_cond_expr_edges (basic_block bb)
586 tree entry = last_stmt (bb);
587 basic_block then_bb, else_bb;
588 tree then_label, else_label;
592 gcc_assert (TREE_CODE (entry) == COND_EXPR);
594 /* Entry basic blocks for each component. */
595 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
596 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
597 then_bb = label_to_block (then_label);
598 else_bb = label_to_block (else_label);
600 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
601 #ifdef USE_MAPPED_LOCATION
602 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
604 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
606 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
609 #ifdef USE_MAPPED_LOCATION
610 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
612 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
618 /* Called for each element in the hash table (P) as we delete the
619 edge to cases hash table.
621 Clear all the TREE_CHAINs to prevent problems with copying of
622 SWITCH_EXPRs and structure sharing rules, then free the hash table
626 edge_to_cases_cleanup (void *key ATTRIBUTE_UNUSED, void **value,
627 void *data ATTRIBUTE_UNUSED)
631 for (t = (tree) *value; t; t = next)
633 next = TREE_CHAIN (t);
634 TREE_CHAIN (t) = NULL;
641 /* Start recording information mapping edges to case labels. */
644 start_recording_case_labels (void)
646 gcc_assert (edge_to_cases == NULL);
647 edge_to_cases = pointer_map_create ();
650 /* Return nonzero if we are recording information for case labels. */
653 recording_case_labels_p (void)
655 return (edge_to_cases != NULL);
658 /* Stop recording information mapping edges to case labels and
659 remove any information we have recorded. */
661 end_recording_case_labels (void)
663 pointer_map_traverse (edge_to_cases, edge_to_cases_cleanup, NULL);
664 pointer_map_destroy (edge_to_cases);
665 edge_to_cases = NULL;
668 /* If we are inside a {start,end}_recording_cases block, then return
669 a chain of CASE_LABEL_EXPRs from T which reference E.
671 Otherwise return NULL. */
674 get_cases_for_edge (edge e, tree t)
680 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
681 chains available. Return NULL so the caller can detect this case. */
682 if (!recording_case_labels_p ())
685 slot = pointer_map_contains (edge_to_cases, e);
689 /* If we did not find E in the hash table, then this must be the first
690 time we have been queried for information about E & T. Add all the
691 elements from T to the hash table then perform the query again. */
693 vec = SWITCH_LABELS (t);
694 n = TREE_VEC_LENGTH (vec);
695 for (i = 0; i < n; i++)
697 tree elt = TREE_VEC_ELT (vec, i);
698 tree lab = CASE_LABEL (elt);
699 basic_block label_bb = label_to_block (lab);
700 edge this_edge = find_edge (e->src, label_bb);
702 /* Add it to the chain of CASE_LABEL_EXPRs referencing E, or create
704 slot = pointer_map_insert (edge_to_cases, this_edge);
705 TREE_CHAIN (elt) = (tree) *slot;
709 return (tree) *pointer_map_contains (edge_to_cases, e);
712 /* Create the edges for a SWITCH_EXPR starting at block BB.
713 At this point, the switch body has been lowered and the
714 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
717 make_switch_expr_edges (basic_block bb)
719 tree entry = last_stmt (bb);
723 vec = SWITCH_LABELS (entry);
724 n = TREE_VEC_LENGTH (vec);
726 for (i = 0; i < n; ++i)
728 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
729 basic_block label_bb = label_to_block (lab);
730 make_edge (bb, label_bb, 0);
735 /* Return the basic block holding label DEST. */
738 label_to_block_fn (struct function *ifun, tree dest)
740 int uid = LABEL_DECL_UID (dest);
742 /* We would die hard when faced by an undefined label. Emit a label to
743 the very first basic block. This will hopefully make even the dataflow
744 and undefined variable warnings quite right. */
745 if ((errorcount || sorrycount) && uid < 0)
747 block_stmt_iterator bsi =
748 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
751 stmt = build1 (LABEL_EXPR, void_type_node, dest);
752 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
753 uid = LABEL_DECL_UID (dest);
755 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
756 <= (unsigned int) uid)
758 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
761 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
762 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
765 make_abnormal_goto_edges (basic_block bb, bool for_call)
767 basic_block target_bb;
768 block_stmt_iterator bsi;
770 FOR_EACH_BB (target_bb)
771 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
773 tree target = bsi_stmt (bsi);
775 if (TREE_CODE (target) != LABEL_EXPR)
778 target = LABEL_EXPR_LABEL (target);
780 /* Make an edge to every label block that has been marked as a
781 potential target for a computed goto or a non-local goto. */
782 if ((FORCED_LABEL (target) && !for_call)
783 || (DECL_NONLOCAL (target) && for_call))
785 make_edge (bb, target_bb, EDGE_ABNORMAL);
791 /* Create edges for a goto statement at block BB. */
794 make_goto_expr_edges (basic_block bb)
796 block_stmt_iterator last = bsi_last (bb);
797 tree goto_t = bsi_stmt (last);
799 /* A simple GOTO creates normal edges. */
800 if (simple_goto_p (goto_t))
802 tree dest = GOTO_DESTINATION (goto_t);
803 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
804 #ifdef USE_MAPPED_LOCATION
805 e->goto_locus = EXPR_LOCATION (goto_t);
807 e->goto_locus = EXPR_LOCUS (goto_t);
809 bsi_remove (&last, true);
813 /* A computed GOTO creates abnormal edges. */
814 make_abnormal_goto_edges (bb, false);
818 /*---------------------------------------------------------------------------
820 ---------------------------------------------------------------------------*/
822 /* Cleanup useless labels in basic blocks. This is something we wish
823 to do early because it allows us to group case labels before creating
824 the edges for the CFG, and it speeds up block statement iterators in
826 We only run this pass once, running it more than once is probably not
829 /* A map from basic block index to the leading label of that block. */
830 static tree *label_for_bb;
832 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
834 update_eh_label (struct eh_region *region)
836 tree old_label = get_eh_region_tree_label (region);
840 basic_block bb = label_to_block (old_label);
842 /* ??? After optimizing, there may be EH regions with labels
843 that have already been removed from the function body, so
844 there is no basic block for them. */
848 new_label = label_for_bb[bb->index];
849 set_eh_region_tree_label (region, new_label);
853 /* Given LABEL return the first label in the same basic block. */
855 main_block_label (tree label)
857 basic_block bb = label_to_block (label);
859 /* label_to_block possibly inserted undefined label into the chain. */
860 if (!label_for_bb[bb->index])
861 label_for_bb[bb->index] = label;
862 return label_for_bb[bb->index];
865 /* Cleanup redundant labels. This is a three-step process:
866 1) Find the leading label for each block.
867 2) Redirect all references to labels to the leading labels.
868 3) Cleanup all useless labels. */
871 cleanup_dead_labels (void)
874 label_for_bb = XCNEWVEC (tree, last_basic_block);
876 /* Find a suitable label for each block. We use the first user-defined
877 label if there is one, or otherwise just the first label we see. */
880 block_stmt_iterator i;
882 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
884 tree label, stmt = bsi_stmt (i);
886 if (TREE_CODE (stmt) != LABEL_EXPR)
889 label = LABEL_EXPR_LABEL (stmt);
891 /* If we have not yet seen a label for the current block,
892 remember this one and see if there are more labels. */
893 if (! label_for_bb[bb->index])
895 label_for_bb[bb->index] = label;
899 /* If we did see a label for the current block already, but it
900 is an artificially created label, replace it if the current
901 label is a user defined label. */
902 if (! DECL_ARTIFICIAL (label)
903 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
905 label_for_bb[bb->index] = label;
911 /* Now redirect all jumps/branches to the selected label.
912 First do so for each block ending in a control statement. */
915 tree stmt = last_stmt (bb);
919 switch (TREE_CODE (stmt))
923 tree true_branch, false_branch;
925 true_branch = COND_EXPR_THEN (stmt);
926 false_branch = COND_EXPR_ELSE (stmt);
928 GOTO_DESTINATION (true_branch)
929 = main_block_label (GOTO_DESTINATION (true_branch));
930 GOTO_DESTINATION (false_branch)
931 = main_block_label (GOTO_DESTINATION (false_branch));
939 tree vec = SWITCH_LABELS (stmt);
940 size_t n = TREE_VEC_LENGTH (vec);
942 /* Replace all destination labels. */
943 for (i = 0; i < n; ++i)
945 tree elt = TREE_VEC_ELT (vec, i);
946 tree label = main_block_label (CASE_LABEL (elt));
947 CASE_LABEL (elt) = label;
952 /* We have to handle GOTO_EXPRs until they're removed, and we don't
953 remove them until after we've created the CFG edges. */
955 if (! computed_goto_p (stmt))
957 GOTO_DESTINATION (stmt)
958 = main_block_label (GOTO_DESTINATION (stmt));
967 for_each_eh_region (update_eh_label);
969 /* Finally, purge dead labels. All user-defined labels and labels that
970 can be the target of non-local gotos and labels which have their
971 address taken are preserved. */
974 block_stmt_iterator i;
975 tree label_for_this_bb = label_for_bb[bb->index];
977 if (! label_for_this_bb)
980 for (i = bsi_start (bb); !bsi_end_p (i); )
982 tree label, stmt = bsi_stmt (i);
984 if (TREE_CODE (stmt) != LABEL_EXPR)
987 label = LABEL_EXPR_LABEL (stmt);
989 if (label == label_for_this_bb
990 || ! DECL_ARTIFICIAL (label)
991 || DECL_NONLOCAL (label)
992 || FORCED_LABEL (label))
995 bsi_remove (&i, true);
1002 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1003 and scan the sorted vector of cases. Combine the ones jumping to the
1005 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1008 group_case_labels (void)
1014 tree stmt = last_stmt (bb);
1015 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1017 tree labels = SWITCH_LABELS (stmt);
1018 int old_size = TREE_VEC_LENGTH (labels);
1019 int i, j, new_size = old_size;
1020 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1023 /* The default label is always the last case in a switch
1024 statement after gimplification. */
1025 default_label = CASE_LABEL (default_case);
1027 /* Look for possible opportunities to merge cases.
1028 Ignore the last element of the label vector because it
1029 must be the default case. */
1031 while (i < old_size - 1)
1033 tree base_case, base_label, base_high;
1034 base_case = TREE_VEC_ELT (labels, i);
1036 gcc_assert (base_case);
1037 base_label = CASE_LABEL (base_case);
1039 /* Discard cases that have the same destination as the
1041 if (base_label == default_label)
1043 TREE_VEC_ELT (labels, i) = NULL_TREE;
1049 base_high = CASE_HIGH (base_case) ?
1050 CASE_HIGH (base_case) : CASE_LOW (base_case);
1052 /* Try to merge case labels. Break out when we reach the end
1053 of the label vector or when we cannot merge the next case
1054 label with the current one. */
1055 while (i < old_size - 1)
1057 tree merge_case = TREE_VEC_ELT (labels, i);
1058 tree merge_label = CASE_LABEL (merge_case);
1059 tree t = int_const_binop (PLUS_EXPR, base_high,
1060 integer_one_node, 1);
1062 /* Merge the cases if they jump to the same place,
1063 and their ranges are consecutive. */
1064 if (merge_label == base_label
1065 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1067 base_high = CASE_HIGH (merge_case) ?
1068 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1069 CASE_HIGH (base_case) = base_high;
1070 TREE_VEC_ELT (labels, i) = NULL_TREE;
1079 /* Compress the case labels in the label vector, and adjust the
1080 length of the vector. */
1081 for (i = 0, j = 0; i < new_size; i++)
1083 while (! TREE_VEC_ELT (labels, j))
1085 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1087 TREE_VEC_LENGTH (labels) = new_size;
1092 /* Checks whether we can merge block B into block A. */
1095 tree_can_merge_blocks_p (basic_block a, basic_block b)
1098 block_stmt_iterator bsi;
1101 if (!single_succ_p (a))
1104 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1107 if (single_succ (a) != b)
1110 if (!single_pred_p (b))
1113 if (b == EXIT_BLOCK_PTR)
1116 /* If A ends by a statement causing exceptions or something similar, we
1117 cannot merge the blocks. */
1118 stmt = last_stmt (a);
1119 if (stmt && stmt_ends_bb_p (stmt))
1122 /* Do not allow a block with only a non-local label to be merged. */
1123 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1124 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1127 /* It must be possible to eliminate all phi nodes in B. If ssa form
1128 is not up-to-date, we cannot eliminate any phis; however, if only
1129 some symbols as whole are marked for renaming, this is not a problem,
1130 as phi nodes for those symbols are irrelevant in updating anyway. */
1131 phi = phi_nodes (b);
1134 if (name_mappings_registered_p ())
1137 for (; phi; phi = PHI_CHAIN (phi))
1138 if (!is_gimple_reg (PHI_RESULT (phi))
1139 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1143 /* Do not remove user labels. */
1144 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1146 stmt = bsi_stmt (bsi);
1147 if (TREE_CODE (stmt) != LABEL_EXPR)
1149 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1153 /* Protect the loop latches. */
1155 && b->loop_father->latch == b)
1161 /* Replaces all uses of NAME by VAL. */
1164 replace_uses_by (tree name, tree val)
1166 imm_use_iterator imm_iter;
1171 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1173 if (TREE_CODE (stmt) != PHI_NODE)
1174 push_stmt_changes (&stmt);
1176 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1178 replace_exp (use, val);
1180 if (TREE_CODE (stmt) == PHI_NODE)
1182 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1183 if (e->flags & EDGE_ABNORMAL)
1185 /* This can only occur for virtual operands, since
1186 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1187 would prevent replacement. */
1188 gcc_assert (!is_gimple_reg (name));
1189 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1194 if (TREE_CODE (stmt) != PHI_NODE)
1198 fold_stmt_inplace (stmt);
1200 /* FIXME. This should go in pop_stmt_changes. */
1201 rhs = get_rhs (stmt);
1202 if (TREE_CODE (rhs) == ADDR_EXPR)
1203 recompute_tree_invariant_for_addr_expr (rhs);
1205 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1207 pop_stmt_changes (&stmt);
1211 gcc_assert (has_zero_uses (name));
1213 /* Also update the trees stored in loop structures. */
1219 FOR_EACH_LOOP (li, loop, 0)
1221 substitute_in_loop_info (loop, name, val);
1226 /* Merge block B into block A. */
1229 tree_merge_blocks (basic_block a, basic_block b)
1231 block_stmt_iterator bsi;
1232 tree_stmt_iterator last;
1236 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1238 /* Remove all single-valued PHI nodes from block B of the form
1239 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1241 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1243 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1245 bool may_replace_uses = may_propagate_copy (def, use);
1247 /* In case we have loops to care about, do not propagate arguments of
1248 loop closed ssa phi nodes. */
1250 && is_gimple_reg (def)
1251 && TREE_CODE (use) == SSA_NAME
1252 && a->loop_father != b->loop_father)
1253 may_replace_uses = false;
1255 if (!may_replace_uses)
1257 gcc_assert (is_gimple_reg (def));
1259 /* Note that just emitting the copies is fine -- there is no problem
1260 with ordering of phi nodes. This is because A is the single
1261 predecessor of B, therefore results of the phi nodes cannot
1262 appear as arguments of the phi nodes. */
1263 copy = build_gimple_modify_stmt (def, use);
1264 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1265 SSA_NAME_DEF_STMT (def) = copy;
1266 remove_phi_node (phi, NULL, false);
1270 replace_uses_by (def, use);
1271 remove_phi_node (phi, NULL, true);
1275 /* Ensure that B follows A. */
1276 move_block_after (b, a);
1278 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1279 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1281 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1282 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1284 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1286 tree label = bsi_stmt (bsi);
1288 bsi_remove (&bsi, false);
1289 /* Now that we can thread computed gotos, we might have
1290 a situation where we have a forced label in block B
1291 However, the label at the start of block B might still be
1292 used in other ways (think about the runtime checking for
1293 Fortran assigned gotos). So we can not just delete the
1294 label. Instead we move the label to the start of block A. */
1295 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1297 block_stmt_iterator dest_bsi = bsi_start (a);
1298 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1303 change_bb_for_stmt (bsi_stmt (bsi), a);
1308 /* Merge the chains. */
1309 last = tsi_last (a->stmt_list);
1310 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1311 b->stmt_list = NULL;
1315 /* Return the one of two successors of BB that is not reachable by a
1316 reached by a complex edge, if there is one. Else, return BB. We use
1317 this in optimizations that use post-dominators for their heuristics,
1318 to catch the cases in C++ where function calls are involved. */
1321 single_noncomplex_succ (basic_block bb)
1324 if (EDGE_COUNT (bb->succs) != 2)
1327 e0 = EDGE_SUCC (bb, 0);
1328 e1 = EDGE_SUCC (bb, 1);
1329 if (e0->flags & EDGE_COMPLEX)
1331 if (e1->flags & EDGE_COMPLEX)
1338 /* Walk the function tree removing unnecessary statements.
1340 * Empty statement nodes are removed
1342 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1344 * Unnecessary COND_EXPRs are removed
1346 * Some unnecessary BIND_EXPRs are removed
1348 Clearly more work could be done. The trick is doing the analysis
1349 and removal fast enough to be a net improvement in compile times.
1351 Note that when we remove a control structure such as a COND_EXPR
1352 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1353 to ensure we eliminate all the useless code. */
1364 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1367 remove_useless_stmts_warn_notreached (tree stmt)
1369 if (EXPR_HAS_LOCATION (stmt))
1371 location_t loc = EXPR_LOCATION (stmt);
1372 if (LOCATION_LINE (loc) > 0)
1374 warning (0, "%Hwill never be executed", &loc);
1379 switch (TREE_CODE (stmt))
1381 case STATEMENT_LIST:
1383 tree_stmt_iterator i;
1384 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1385 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1391 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1393 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1395 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1399 case TRY_FINALLY_EXPR:
1400 case TRY_CATCH_EXPR:
1401 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1403 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1408 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1409 case EH_FILTER_EXPR:
1410 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1412 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1415 /* Not a live container. */
1423 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1425 tree then_clause, else_clause, cond;
1426 bool save_has_label, then_has_label, else_has_label;
1428 save_has_label = data->has_label;
1429 data->has_label = false;
1430 data->last_goto = NULL;
1432 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1434 then_has_label = data->has_label;
1435 data->has_label = false;
1436 data->last_goto = NULL;
1438 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1440 else_has_label = data->has_label;
1441 data->has_label = save_has_label | then_has_label | else_has_label;
1443 then_clause = COND_EXPR_THEN (*stmt_p);
1444 else_clause = COND_EXPR_ELSE (*stmt_p);
1445 cond = fold (COND_EXPR_COND (*stmt_p));
1447 /* If neither arm does anything at all, we can remove the whole IF. */
1448 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1450 *stmt_p = build_empty_stmt ();
1451 data->repeat = true;
1454 /* If there are no reachable statements in an arm, then we can
1455 zap the entire conditional. */
1456 else if (integer_nonzerop (cond) && !else_has_label)
1458 if (warn_notreached)
1459 remove_useless_stmts_warn_notreached (else_clause);
1460 *stmt_p = then_clause;
1461 data->repeat = true;
1463 else if (integer_zerop (cond) && !then_has_label)
1465 if (warn_notreached)
1466 remove_useless_stmts_warn_notreached (then_clause);
1467 *stmt_p = else_clause;
1468 data->repeat = true;
1471 /* Check a couple of simple things on then/else with single stmts. */
1474 tree then_stmt = expr_only (then_clause);
1475 tree else_stmt = expr_only (else_clause);
1477 /* Notice branches to a common destination. */
1478 if (then_stmt && else_stmt
1479 && TREE_CODE (then_stmt) == GOTO_EXPR
1480 && TREE_CODE (else_stmt) == GOTO_EXPR
1481 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1483 *stmt_p = then_stmt;
1484 data->repeat = true;
1487 /* If the THEN/ELSE clause merely assigns a value to a variable or
1488 parameter which is already known to contain that value, then
1489 remove the useless THEN/ELSE clause. */
1490 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1493 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1494 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1495 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1496 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1498 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1499 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1500 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1501 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1503 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1504 ? then_stmt : else_stmt);
1505 tree *location = (TREE_CODE (cond) == EQ_EXPR
1506 ? &COND_EXPR_THEN (*stmt_p)
1507 : &COND_EXPR_ELSE (*stmt_p));
1510 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1511 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1512 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1513 *location = alloc_stmt_list ();
1517 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1518 would be re-introduced during lowering. */
1519 data->last_goto = NULL;
1524 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1526 bool save_may_branch, save_may_throw;
1527 bool this_may_branch, this_may_throw;
1529 /* Collect may_branch and may_throw information for the body only. */
1530 save_may_branch = data->may_branch;
1531 save_may_throw = data->may_throw;
1532 data->may_branch = false;
1533 data->may_throw = false;
1534 data->last_goto = NULL;
1536 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1538 this_may_branch = data->may_branch;
1539 this_may_throw = data->may_throw;
1540 data->may_branch |= save_may_branch;
1541 data->may_throw |= save_may_throw;
1542 data->last_goto = NULL;
1544 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1546 /* If the body is empty, then we can emit the FINALLY block without
1547 the enclosing TRY_FINALLY_EXPR. */
1548 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1550 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1551 data->repeat = true;
1554 /* If the handler is empty, then we can emit the TRY block without
1555 the enclosing TRY_FINALLY_EXPR. */
1556 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1558 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1559 data->repeat = true;
1562 /* If the body neither throws, nor branches, then we can safely
1563 string the TRY and FINALLY blocks together. */
1564 else if (!this_may_branch && !this_may_throw)
1566 tree stmt = *stmt_p;
1567 *stmt_p = TREE_OPERAND (stmt, 0);
1568 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1569 data->repeat = true;
1575 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1577 bool save_may_throw, this_may_throw;
1578 tree_stmt_iterator i;
1581 /* Collect may_throw information for the body only. */
1582 save_may_throw = data->may_throw;
1583 data->may_throw = false;
1584 data->last_goto = NULL;
1586 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1588 this_may_throw = data->may_throw;
1589 data->may_throw = save_may_throw;
1591 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1592 if (!this_may_throw)
1594 if (warn_notreached)
1595 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1596 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1597 data->repeat = true;
1601 /* Process the catch clause specially. We may be able to tell that
1602 no exceptions propagate past this point. */
1604 this_may_throw = true;
1605 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1606 stmt = tsi_stmt (i);
1607 data->last_goto = NULL;
1609 switch (TREE_CODE (stmt))
1612 for (; !tsi_end_p (i); tsi_next (&i))
1614 stmt = tsi_stmt (i);
1615 /* If we catch all exceptions, then the body does not
1616 propagate exceptions past this point. */
1617 if (CATCH_TYPES (stmt) == NULL)
1618 this_may_throw = false;
1619 data->last_goto = NULL;
1620 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1624 case EH_FILTER_EXPR:
1625 if (EH_FILTER_MUST_NOT_THROW (stmt))
1626 this_may_throw = false;
1627 else if (EH_FILTER_TYPES (stmt) == NULL)
1628 this_may_throw = false;
1629 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1633 /* Otherwise this is a cleanup. */
1634 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1636 /* If the cleanup is empty, then we can emit the TRY block without
1637 the enclosing TRY_CATCH_EXPR. */
1638 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1640 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1641 data->repeat = true;
1645 data->may_throw |= this_may_throw;
1650 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1654 /* First remove anything underneath the BIND_EXPR. */
1655 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1657 /* If the BIND_EXPR has no variables, then we can pull everything
1658 up one level and remove the BIND_EXPR, unless this is the toplevel
1659 BIND_EXPR for the current function or an inlined function.
1661 When this situation occurs we will want to apply this
1662 optimization again. */
1663 block = BIND_EXPR_BLOCK (*stmt_p);
1664 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1665 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1667 || ! BLOCK_ABSTRACT_ORIGIN (block)
1668 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1671 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1672 data->repeat = true;
1678 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1680 tree dest = GOTO_DESTINATION (*stmt_p);
1682 data->may_branch = true;
1683 data->last_goto = NULL;
1685 /* Record the last goto expr, so that we can delete it if unnecessary. */
1686 if (TREE_CODE (dest) == LABEL_DECL)
1687 data->last_goto = stmt_p;
1692 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1694 tree label = LABEL_EXPR_LABEL (*stmt_p);
1696 data->has_label = true;
1698 /* We do want to jump across non-local label receiver code. */
1699 if (DECL_NONLOCAL (label))
1700 data->last_goto = NULL;
1702 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1704 *data->last_goto = build_empty_stmt ();
1705 data->repeat = true;
1708 /* ??? Add something here to delete unused labels. */
1712 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1713 decl. This allows us to eliminate redundant or useless
1714 calls to "const" functions.
1716 Gimplifier already does the same operation, but we may notice functions
1717 being const and pure once their calls has been gimplified, so we need
1718 to update the flag. */
1721 update_call_expr_flags (tree call)
1723 tree decl = get_callee_fndecl (call);
1726 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1727 TREE_SIDE_EFFECTS (call) = 0;
1728 if (TREE_NOTHROW (decl))
1729 TREE_NOTHROW (call) = 1;
1733 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1736 notice_special_calls (tree t)
1738 int flags = call_expr_flags (t);
1740 if (flags & ECF_MAY_BE_ALLOCA)
1741 current_function_calls_alloca = true;
1742 if (flags & ECF_RETURNS_TWICE)
1743 current_function_calls_setjmp = true;
1747 /* Clear flags set by notice_special_calls. Used by dead code removal
1748 to update the flags. */
1751 clear_special_calls (void)
1753 current_function_calls_alloca = false;
1754 current_function_calls_setjmp = false;
1759 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1763 switch (TREE_CODE (t))
1766 remove_useless_stmts_cond (tp, data);
1769 case TRY_FINALLY_EXPR:
1770 remove_useless_stmts_tf (tp, data);
1773 case TRY_CATCH_EXPR:
1774 remove_useless_stmts_tc (tp, data);
1778 remove_useless_stmts_bind (tp, data);
1782 remove_useless_stmts_goto (tp, data);
1786 remove_useless_stmts_label (tp, data);
1791 data->last_goto = NULL;
1792 data->may_branch = true;
1797 data->last_goto = NULL;
1798 notice_special_calls (t);
1799 update_call_expr_flags (t);
1800 if (tree_could_throw_p (t))
1801 data->may_throw = true;
1807 case GIMPLE_MODIFY_STMT:
1808 data->last_goto = NULL;
1810 op = get_call_expr_in (t);
1813 update_call_expr_flags (op);
1814 notice_special_calls (op);
1816 if (tree_could_throw_p (t))
1817 data->may_throw = true;
1820 case STATEMENT_LIST:
1822 tree_stmt_iterator i = tsi_start (t);
1823 while (!tsi_end_p (i))
1826 if (IS_EMPTY_STMT (t))
1832 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1835 if (TREE_CODE (t) == STATEMENT_LIST)
1837 tsi_link_before (&i, t, TSI_SAME_STMT);
1847 data->last_goto = NULL;
1851 data->last_goto = NULL;
1857 remove_useless_stmts (void)
1859 struct rus_data data;
1861 clear_special_calls ();
1865 memset (&data, 0, sizeof (data));
1866 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1868 while (data.repeat);
1873 struct tree_opt_pass pass_remove_useless_stmts =
1875 "useless", /* name */
1877 remove_useless_stmts, /* execute */
1880 0, /* static_pass_number */
1882 PROP_gimple_any, /* properties_required */
1883 0, /* properties_provided */
1884 0, /* properties_destroyed */
1885 0, /* todo_flags_start */
1886 TODO_dump_func, /* todo_flags_finish */
1890 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1893 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1897 /* Since this block is no longer reachable, we can just delete all
1898 of its PHI nodes. */
1899 phi = phi_nodes (bb);
1902 tree next = PHI_CHAIN (phi);
1903 remove_phi_node (phi, NULL_TREE, true);
1907 /* Remove edges to BB's successors. */
1908 while (EDGE_COUNT (bb->succs) > 0)
1909 remove_edge (EDGE_SUCC (bb, 0));
1913 /* Remove statements of basic block BB. */
1916 remove_bb (basic_block bb)
1918 block_stmt_iterator i;
1919 #ifdef USE_MAPPED_LOCATION
1920 source_location loc = UNKNOWN_LOCATION;
1922 source_locus loc = 0;
1927 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1928 if (dump_flags & TDF_DETAILS)
1930 dump_bb (bb, dump_file, 0);
1931 fprintf (dump_file, "\n");
1937 struct loop *loop = bb->loop_father;
1939 /* If a loop gets removed, clean up the information associated
1941 if (loop->latch == bb
1942 || loop->header == bb)
1943 free_numbers_of_iterations_estimates_loop (loop);
1946 /* Remove all the instructions in the block. */
1947 for (i = bsi_start (bb); !bsi_end_p (i);)
1949 tree stmt = bsi_stmt (i);
1950 if (TREE_CODE (stmt) == LABEL_EXPR
1951 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
1952 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
1955 block_stmt_iterator new_bsi;
1957 /* A non-reachable non-local label may still be referenced.
1958 But it no longer needs to carry the extra semantics of
1960 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1962 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
1963 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
1966 new_bb = bb->prev_bb;
1967 new_bsi = bsi_start (new_bb);
1968 bsi_remove (&i, false);
1969 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
1973 /* Release SSA definitions if we are in SSA. Note that we
1974 may be called when not in SSA. For example,
1975 final_cleanup calls this function via
1976 cleanup_tree_cfg. */
1977 if (gimple_in_ssa_p (cfun))
1978 release_defs (stmt);
1980 bsi_remove (&i, true);
1983 /* Don't warn for removed gotos. Gotos are often removed due to
1984 jump threading, thus resulting in bogus warnings. Not great,
1985 since this way we lose warnings for gotos in the original
1986 program that are indeed unreachable. */
1987 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
1989 #ifdef USE_MAPPED_LOCATION
1990 if (EXPR_HAS_LOCATION (stmt))
1991 loc = EXPR_LOCATION (stmt);
1994 t = EXPR_LOCUS (stmt);
1995 if (t && LOCATION_LINE (*t) > 0)
2001 /* If requested, give a warning that the first statement in the
2002 block is unreachable. We walk statements backwards in the
2003 loop above, so the last statement we process is the first statement
2005 #ifdef USE_MAPPED_LOCATION
2006 if (loc > BUILTINS_LOCATION)
2007 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2010 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2013 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2017 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2018 predicate VAL, return the edge that will be taken out of the block.
2019 If VAL does not match a unique edge, NULL is returned. */
2022 find_taken_edge (basic_block bb, tree val)
2026 stmt = last_stmt (bb);
2029 gcc_assert (is_ctrl_stmt (stmt));
2032 if (! is_gimple_min_invariant (val))
2035 if (TREE_CODE (stmt) == COND_EXPR)
2036 return find_taken_edge_cond_expr (bb, val);
2038 if (TREE_CODE (stmt) == SWITCH_EXPR)
2039 return find_taken_edge_switch_expr (bb, val);
2041 if (computed_goto_p (stmt))
2043 /* Only optimize if the argument is a label, if the argument is
2044 not a label then we can not construct a proper CFG.
2046 It may be the case that we only need to allow the LABEL_REF to
2047 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2048 appear inside a LABEL_EXPR just to be safe. */
2049 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2050 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2051 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2058 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2059 statement, determine which of the outgoing edges will be taken out of the
2060 block. Return NULL if either edge may be taken. */
2063 find_taken_edge_computed_goto (basic_block bb, tree val)
2068 dest = label_to_block (val);
2071 e = find_edge (bb, dest);
2072 gcc_assert (e != NULL);
2078 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2079 statement, determine which of the two edges will be taken out of the
2080 block. Return NULL if either edge may be taken. */
2083 find_taken_edge_cond_expr (basic_block bb, tree val)
2085 edge true_edge, false_edge;
2087 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2089 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2090 return (integer_zerop (val) ? false_edge : true_edge);
2093 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2094 statement, determine which edge will be taken out of the block. Return
2095 NULL if any edge may be taken. */
2098 find_taken_edge_switch_expr (basic_block bb, tree val)
2100 tree switch_expr, taken_case;
2101 basic_block dest_bb;
2104 switch_expr = last_stmt (bb);
2105 taken_case = find_case_label_for_value (switch_expr, val);
2106 dest_bb = label_to_block (CASE_LABEL (taken_case));
2108 e = find_edge (bb, dest_bb);
2114 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2115 We can make optimal use here of the fact that the case labels are
2116 sorted: We can do a binary search for a case matching VAL. */
2119 find_case_label_for_value (tree switch_expr, tree val)
2121 tree vec = SWITCH_LABELS (switch_expr);
2122 size_t low, high, n = TREE_VEC_LENGTH (vec);
2123 tree default_case = TREE_VEC_ELT (vec, n - 1);
2125 for (low = -1, high = n - 1; high - low > 1; )
2127 size_t i = (high + low) / 2;
2128 tree t = TREE_VEC_ELT (vec, i);
2131 /* Cache the result of comparing CASE_LOW and val. */
2132 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2139 if (CASE_HIGH (t) == NULL)
2141 /* A singe-valued case label. */
2147 /* A case range. We can only handle integer ranges. */
2148 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2153 return default_case;
2159 /*---------------------------------------------------------------------------
2161 ---------------------------------------------------------------------------*/
2163 /* Dump tree-specific information of block BB to file OUTF. */
2166 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2168 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2172 /* Dump a basic block on stderr. */
2175 debug_tree_bb (basic_block bb)
2177 dump_bb (bb, stderr, 0);
2181 /* Dump basic block with index N on stderr. */
2184 debug_tree_bb_n (int n)
2186 debug_tree_bb (BASIC_BLOCK (n));
2187 return BASIC_BLOCK (n);
2191 /* Dump the CFG on stderr.
2193 FLAGS are the same used by the tree dumping functions
2194 (see TDF_* in tree-pass.h). */
2197 debug_tree_cfg (int flags)
2199 dump_tree_cfg (stderr, flags);
2203 /* Dump the program showing basic block boundaries on the given FILE.
2205 FLAGS are the same used by the tree dumping functions (see TDF_* in
2209 dump_tree_cfg (FILE *file, int flags)
2211 if (flags & TDF_DETAILS)
2213 const char *funcname
2214 = lang_hooks.decl_printable_name (current_function_decl, 2);
2217 fprintf (file, ";; Function %s\n\n", funcname);
2218 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2219 n_basic_blocks, n_edges, last_basic_block);
2221 brief_dump_cfg (file);
2222 fprintf (file, "\n");
2225 if (flags & TDF_STATS)
2226 dump_cfg_stats (file);
2228 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2232 /* Dump CFG statistics on FILE. */
2235 dump_cfg_stats (FILE *file)
2237 static long max_num_merged_labels = 0;
2238 unsigned long size, total = 0;
2241 const char * const fmt_str = "%-30s%-13s%12s\n";
2242 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2243 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2244 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2245 const char *funcname
2246 = lang_hooks.decl_printable_name (current_function_decl, 2);
2249 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2251 fprintf (file, "---------------------------------------------------------\n");
2252 fprintf (file, fmt_str, "", " Number of ", "Memory");
2253 fprintf (file, fmt_str, "", " instances ", "used ");
2254 fprintf (file, "---------------------------------------------------------\n");
2256 size = n_basic_blocks * sizeof (struct basic_block_def);
2258 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2259 SCALE (size), LABEL (size));
2263 num_edges += EDGE_COUNT (bb->succs);
2264 size = num_edges * sizeof (struct edge_def);
2266 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2268 fprintf (file, "---------------------------------------------------------\n");
2269 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2271 fprintf (file, "---------------------------------------------------------\n");
2272 fprintf (file, "\n");
2274 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2275 max_num_merged_labels = cfg_stats.num_merged_labels;
2277 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2278 cfg_stats.num_merged_labels, max_num_merged_labels);
2280 fprintf (file, "\n");
2284 /* Dump CFG statistics on stderr. Keep extern so that it's always
2285 linked in the final executable. */
2288 debug_cfg_stats (void)
2290 dump_cfg_stats (stderr);
2294 /* Dump the flowgraph to a .vcg FILE. */
2297 tree_cfg2vcg (FILE *file)
2302 const char *funcname
2303 = lang_hooks.decl_printable_name (current_function_decl, 2);
2305 /* Write the file header. */
2306 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2307 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2308 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2310 /* Write blocks and edges. */
2311 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2313 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2316 if (e->flags & EDGE_FAKE)
2317 fprintf (file, " linestyle: dotted priority: 10");
2319 fprintf (file, " linestyle: solid priority: 100");
2321 fprintf (file, " }\n");
2327 enum tree_code head_code, end_code;
2328 const char *head_name, *end_name;
2331 tree first = first_stmt (bb);
2332 tree last = last_stmt (bb);
2336 head_code = TREE_CODE (first);
2337 head_name = tree_code_name[head_code];
2338 head_line = get_lineno (first);
2341 head_name = "no-statement";
2345 end_code = TREE_CODE (last);
2346 end_name = tree_code_name[end_code];
2347 end_line = get_lineno (last);
2350 end_name = "no-statement";
2352 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2353 bb->index, bb->index, head_name, head_line, end_name,
2356 FOR_EACH_EDGE (e, ei, bb->succs)
2358 if (e->dest == EXIT_BLOCK_PTR)
2359 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2361 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2363 if (e->flags & EDGE_FAKE)
2364 fprintf (file, " priority: 10 linestyle: dotted");
2366 fprintf (file, " priority: 100 linestyle: solid");
2368 fprintf (file, " }\n");
2371 if (bb->next_bb != EXIT_BLOCK_PTR)
2375 fputs ("}\n\n", file);
2380 /*---------------------------------------------------------------------------
2381 Miscellaneous helpers
2382 ---------------------------------------------------------------------------*/
2384 /* Return true if T represents a stmt that always transfers control. */
2387 is_ctrl_stmt (tree t)
2389 return (TREE_CODE (t) == COND_EXPR
2390 || TREE_CODE (t) == SWITCH_EXPR
2391 || TREE_CODE (t) == GOTO_EXPR
2392 || TREE_CODE (t) == RETURN_EXPR
2393 || TREE_CODE (t) == RESX_EXPR);
2397 /* Return true if T is a statement that may alter the flow of control
2398 (e.g., a call to a non-returning function). */
2401 is_ctrl_altering_stmt (tree t)
2406 call = get_call_expr_in (t);
2409 /* A non-pure/const CALL_EXPR alters flow control if the current
2410 function has nonlocal labels. */
2411 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2414 /* A CALL_EXPR also alters control flow if it does not return. */
2415 if (call_expr_flags (call) & ECF_NORETURN)
2419 /* OpenMP directives alter control flow. */
2420 if (OMP_DIRECTIVE_P (t))
2423 /* If a statement can throw, it alters control flow. */
2424 return tree_can_throw_internal (t);
2428 /* Return true if T is a computed goto. */
2431 computed_goto_p (tree t)
2433 return (TREE_CODE (t) == GOTO_EXPR
2434 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2438 /* Return true if T is a simple local goto. */
2441 simple_goto_p (tree t)
2443 return (TREE_CODE (t) == GOTO_EXPR
2444 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2448 /* Return true if T can make an abnormal transfer of control flow.
2449 Transfers of control flow associated with EH are excluded. */
2452 tree_can_make_abnormal_goto (tree t)
2454 if (computed_goto_p (t))
2456 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2457 t = GIMPLE_STMT_OPERAND (t, 1);
2458 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2459 t = TREE_OPERAND (t, 0);
2460 if (TREE_CODE (t) == CALL_EXPR)
2461 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2466 /* Return true if T should start a new basic block. PREV_T is the
2467 statement preceding T. It is used when T is a label or a case label.
2468 Labels should only start a new basic block if their previous statement
2469 wasn't a label. Otherwise, sequence of labels would generate
2470 unnecessary basic blocks that only contain a single label. */
2473 stmt_starts_bb_p (tree t, tree prev_t)
2478 /* LABEL_EXPRs start a new basic block only if the preceding
2479 statement wasn't a label of the same type. This prevents the
2480 creation of consecutive blocks that have nothing but a single
2482 if (TREE_CODE (t) == LABEL_EXPR)
2484 /* Nonlocal and computed GOTO targets always start a new block. */
2485 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2486 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2489 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2491 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2494 cfg_stats.num_merged_labels++;
2505 /* Return true if T should end a basic block. */
2508 stmt_ends_bb_p (tree t)
2510 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2514 /* Add gotos that used to be represented implicitly in the CFG. */
2517 disband_implicit_edges (void)
2520 block_stmt_iterator last;
2527 last = bsi_last (bb);
2528 stmt = last_stmt (bb);
2530 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2532 /* Remove superfluous gotos from COND_EXPR branches. Moved
2533 from cfg_remove_useless_stmts here since it violates the
2534 invariants for tree--cfg correspondence and thus fits better
2535 here where we do it anyway. */
2536 e = find_edge (bb, bb->next_bb);
2539 if (e->flags & EDGE_TRUE_VALUE)
2540 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2541 else if (e->flags & EDGE_FALSE_VALUE)
2542 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2545 e->flags |= EDGE_FALLTHRU;
2551 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2553 /* Remove the RETURN_EXPR if we may fall though to the exit
2555 gcc_assert (single_succ_p (bb));
2556 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2558 if (bb->next_bb == EXIT_BLOCK_PTR
2559 && !TREE_OPERAND (stmt, 0))
2561 bsi_remove (&last, true);
2562 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2567 /* There can be no fallthru edge if the last statement is a control
2569 if (stmt && is_ctrl_stmt (stmt))
2572 /* Find a fallthru edge and emit the goto if necessary. */
2573 FOR_EACH_EDGE (e, ei, bb->succs)
2574 if (e->flags & EDGE_FALLTHRU)
2577 if (!e || e->dest == bb->next_bb)
2580 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2581 label = tree_block_label (e->dest);
2583 stmt = build1 (GOTO_EXPR, void_type_node, label);
2584 #ifdef USE_MAPPED_LOCATION
2585 SET_EXPR_LOCATION (stmt, e->goto_locus);
2587 SET_EXPR_LOCUS (stmt, e->goto_locus);
2589 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2590 e->flags &= ~EDGE_FALLTHRU;
2594 /* Remove block annotations and other datastructures. */
2597 delete_tree_cfg_annotations (void)
2600 block_stmt_iterator bsi;
2602 /* Remove annotations from every tree in the function. */
2604 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2606 tree stmt = bsi_stmt (bsi);
2607 ggc_free (stmt->base.ann);
2608 stmt->base.ann = NULL;
2610 label_to_block_map = NULL;
2614 /* Return the first statement in basic block BB. */
2617 first_stmt (basic_block bb)
2619 block_stmt_iterator i = bsi_start (bb);
2620 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2624 /* Return the last statement in basic block BB. */
2627 last_stmt (basic_block bb)
2629 block_stmt_iterator b = bsi_last (bb);
2630 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2634 /* Return the last statement of an otherwise empty block. Return NULL
2635 if the block is totally empty, or if it contains more than one
2639 last_and_only_stmt (basic_block bb)
2641 block_stmt_iterator i = bsi_last (bb);
2647 last = bsi_stmt (i);
2652 /* Empty statements should no longer appear in the instruction stream.
2653 Everything that might have appeared before should be deleted by
2654 remove_useless_stmts, and the optimizers should just bsi_remove
2655 instead of smashing with build_empty_stmt.
2657 Thus the only thing that should appear here in a block containing
2658 one executable statement is a label. */
2659 prev = bsi_stmt (i);
2660 if (TREE_CODE (prev) == LABEL_EXPR)
2667 /* Mark BB as the basic block holding statement T. */
2670 set_bb_for_stmt (tree t, basic_block bb)
2672 if (TREE_CODE (t) == PHI_NODE)
2674 else if (TREE_CODE (t) == STATEMENT_LIST)
2676 tree_stmt_iterator i;
2677 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2678 set_bb_for_stmt (tsi_stmt (i), bb);
2682 stmt_ann_t ann = get_stmt_ann (t);
2685 /* If the statement is a label, add the label to block-to-labels map
2686 so that we can speed up edge creation for GOTO_EXPRs. */
2687 if (TREE_CODE (t) == LABEL_EXPR)
2691 t = LABEL_EXPR_LABEL (t);
2692 uid = LABEL_DECL_UID (t);
2695 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2696 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2697 if (old_len <= (unsigned) uid)
2699 unsigned new_len = 3 * uid / 2;
2701 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2706 /* We're moving an existing label. Make sure that we've
2707 removed it from the old block. */
2709 || !VEC_index (basic_block, label_to_block_map, uid));
2710 VEC_replace (basic_block, label_to_block_map, uid, bb);
2715 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2716 from one basic block to another.
2717 For BB splitting we can run into quadratic case, so performance is quite
2718 important and knowing that the tables are big enough, change_bb_for_stmt
2719 can inline as leaf function. */
2721 change_bb_for_stmt (tree t, basic_block bb)
2723 get_stmt_ann (t)->bb = bb;
2724 if (TREE_CODE (t) == LABEL_EXPR)
2725 VEC_replace (basic_block, label_to_block_map,
2726 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2729 /* Finds iterator for STMT. */
2731 extern block_stmt_iterator
2732 bsi_for_stmt (tree stmt)
2734 block_stmt_iterator bsi;
2736 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2737 if (bsi_stmt (bsi) == stmt)
2743 /* Mark statement T as modified, and update it. */
2745 update_modified_stmts (tree t)
2747 if (!ssa_operands_active ())
2749 if (TREE_CODE (t) == STATEMENT_LIST)
2751 tree_stmt_iterator i;
2753 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2755 stmt = tsi_stmt (i);
2756 update_stmt_if_modified (stmt);
2760 update_stmt_if_modified (t);
2763 /* Insert statement (or statement list) T before the statement
2764 pointed-to by iterator I. M specifies how to update iterator I
2765 after insertion (see enum bsi_iterator_update). */
2768 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2770 set_bb_for_stmt (t, i->bb);
2771 update_modified_stmts (t);
2772 tsi_link_before (&i->tsi, t, m);
2776 /* Insert statement (or statement list) T after the statement
2777 pointed-to by iterator I. M specifies how to update iterator I
2778 after insertion (see enum bsi_iterator_update). */
2781 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2783 set_bb_for_stmt (t, i->bb);
2784 update_modified_stmts (t);
2785 tsi_link_after (&i->tsi, t, m);
2789 /* Remove the statement pointed to by iterator I. The iterator is updated
2790 to the next statement.
2792 When REMOVE_EH_INFO is true we remove the statement pointed to by
2793 iterator I from the EH tables. Otherwise we do not modify the EH
2796 Generally, REMOVE_EH_INFO should be true when the statement is going to
2797 be removed from the IL and not reinserted elsewhere. */
2800 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2802 tree t = bsi_stmt (*i);
2803 set_bb_for_stmt (t, NULL);
2804 delink_stmt_imm_use (t);
2805 tsi_delink (&i->tsi);
2806 mark_stmt_modified (t);
2809 remove_stmt_from_eh_region (t);
2810 gimple_remove_stmt_histograms (cfun, t);
2815 /* Move the statement at FROM so it comes right after the statement at TO. */
2818 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2820 tree stmt = bsi_stmt (*from);
2821 bsi_remove (from, false);
2822 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2826 /* Move the statement at FROM so it comes right before the statement at TO. */
2829 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2831 tree stmt = bsi_stmt (*from);
2832 bsi_remove (from, false);
2833 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2837 /* Move the statement at FROM to the end of basic block BB. */
2840 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2842 block_stmt_iterator last = bsi_last (bb);
2844 /* Have to check bsi_end_p because it could be an empty block. */
2845 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2846 bsi_move_before (from, &last);
2848 bsi_move_after (from, &last);
2852 /* Replace the contents of the statement pointed to by iterator BSI
2853 with STMT. If UPDATE_EH_INFO is true, the exception handling
2854 information of the original statement is moved to the new statement. */
2857 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2860 tree orig_stmt = bsi_stmt (*bsi);
2862 if (stmt == orig_stmt)
2864 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2865 set_bb_for_stmt (stmt, bsi->bb);
2867 /* Preserve EH region information from the original statement, if
2868 requested by the caller. */
2871 eh_region = lookup_stmt_eh_region (orig_stmt);
2874 remove_stmt_from_eh_region (orig_stmt);
2875 add_stmt_to_eh_region (stmt, eh_region);
2879 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2880 gimple_remove_stmt_histograms (cfun, orig_stmt);
2881 delink_stmt_imm_use (orig_stmt);
2882 *bsi_stmt_ptr (*bsi) = stmt;
2883 mark_stmt_modified (stmt);
2884 update_modified_stmts (stmt);
2888 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2889 is made to place the statement in an existing basic block, but
2890 sometimes that isn't possible. When it isn't possible, the edge is
2891 split and the statement is added to the new block.
2893 In all cases, the returned *BSI points to the correct location. The
2894 return value is true if insertion should be done after the location,
2895 or false if it should be done before the location. If new basic block
2896 has to be created, it is stored in *NEW_BB. */
2899 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2900 basic_block *new_bb)
2902 basic_block dest, src;
2908 /* If the destination has one predecessor which has no PHI nodes,
2909 insert there. Except for the exit block.
2911 The requirement for no PHI nodes could be relaxed. Basically we
2912 would have to examine the PHIs to prove that none of them used
2913 the value set by the statement we want to insert on E. That
2914 hardly seems worth the effort. */
2915 if (single_pred_p (dest)
2916 && ! phi_nodes (dest)
2917 && dest != EXIT_BLOCK_PTR)
2919 *bsi = bsi_start (dest);
2920 if (bsi_end_p (*bsi))
2923 /* Make sure we insert after any leading labels. */
2924 tmp = bsi_stmt (*bsi);
2925 while (TREE_CODE (tmp) == LABEL_EXPR)
2928 if (bsi_end_p (*bsi))
2930 tmp = bsi_stmt (*bsi);
2933 if (bsi_end_p (*bsi))
2935 *bsi = bsi_last (dest);
2942 /* If the source has one successor, the edge is not abnormal and
2943 the last statement does not end a basic block, insert there.
2944 Except for the entry block. */
2946 if ((e->flags & EDGE_ABNORMAL) == 0
2947 && single_succ_p (src)
2948 && src != ENTRY_BLOCK_PTR)
2950 *bsi = bsi_last (src);
2951 if (bsi_end_p (*bsi))
2954 tmp = bsi_stmt (*bsi);
2955 if (!stmt_ends_bb_p (tmp))
2958 /* Insert code just before returning the value. We may need to decompose
2959 the return in the case it contains non-trivial operand. */
2960 if (TREE_CODE (tmp) == RETURN_EXPR)
2962 tree op = TREE_OPERAND (tmp, 0);
2963 if (op && !is_gimple_val (op))
2965 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
2966 bsi_insert_before (bsi, op, BSI_NEW_STMT);
2967 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
2974 /* Otherwise, create a new basic block, and split this edge. */
2975 dest = split_edge (e);
2978 e = single_pred_edge (dest);
2983 /* This routine will commit all pending edge insertions, creating any new
2984 basic blocks which are necessary. */
2987 bsi_commit_edge_inserts (void)
2993 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
2996 FOR_EACH_EDGE (e, ei, bb->succs)
2997 bsi_commit_one_edge_insert (e, NULL);
3001 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3002 to this block, otherwise set it to NULL. */
3005 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3009 if (PENDING_STMT (e))
3011 block_stmt_iterator bsi;
3012 tree stmt = PENDING_STMT (e);
3014 PENDING_STMT (e) = NULL_TREE;
3016 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3017 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3019 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3024 /* Add STMT to the pending list of edge E. No actual insertion is
3025 made until a call to bsi_commit_edge_inserts () is made. */
3028 bsi_insert_on_edge (edge e, tree stmt)
3030 append_to_statement_list (stmt, &PENDING_STMT (e));
3033 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3034 block has to be created, it is returned. */
3037 bsi_insert_on_edge_immediate (edge e, tree stmt)
3039 block_stmt_iterator bsi;
3040 basic_block new_bb = NULL;
3042 gcc_assert (!PENDING_STMT (e));
3044 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3045 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3047 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3052 /*---------------------------------------------------------------------------
3053 Tree specific functions for CFG manipulation
3054 ---------------------------------------------------------------------------*/
3056 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3059 reinstall_phi_args (edge new_edge, edge old_edge)
3063 if (!PENDING_STMT (old_edge))
3066 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3068 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3070 tree result = TREE_PURPOSE (var);
3071 tree arg = TREE_VALUE (var);
3073 gcc_assert (result == PHI_RESULT (phi));
3075 add_phi_arg (phi, arg, new_edge);
3078 PENDING_STMT (old_edge) = NULL;
3081 /* Returns the basic block after which the new basic block created
3082 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3083 near its "logical" location. This is of most help to humans looking
3084 at debugging dumps. */
3087 split_edge_bb_loc (edge edge_in)
3089 basic_block dest = edge_in->dest;
3091 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3092 return edge_in->src;
3094 return dest->prev_bb;
3097 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3098 Abort on abnormal edges. */
3101 tree_split_edge (edge edge_in)
3103 basic_block new_bb, after_bb, dest;
3106 /* Abnormal edges cannot be split. */
3107 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3109 dest = edge_in->dest;
3111 after_bb = split_edge_bb_loc (edge_in);
3113 new_bb = create_empty_bb (after_bb);
3114 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3115 new_bb->count = edge_in->count;
3116 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3117 new_edge->probability = REG_BR_PROB_BASE;
3118 new_edge->count = edge_in->count;
3120 e = redirect_edge_and_branch (edge_in, new_bb);
3121 gcc_assert (e == edge_in);
3122 reinstall_phi_args (new_edge, e);
3128 /* Return true when BB has label LABEL in it. */
3131 has_label_p (basic_block bb, tree label)
3133 block_stmt_iterator bsi;
3135 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3137 tree stmt = bsi_stmt (bsi);
3139 if (TREE_CODE (stmt) != LABEL_EXPR)
3141 if (LABEL_EXPR_LABEL (stmt) == label)
3148 /* Callback for walk_tree, check that all elements with address taken are
3149 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3150 inside a PHI node. */
3153 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3156 bool in_phi = (data != NULL);
3161 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3162 #define CHECK_OP(N, MSG) \
3163 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3164 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3166 switch (TREE_CODE (t))
3169 if (SSA_NAME_IN_FREE_LIST (t))
3171 error ("SSA name in freelist but still referenced");
3177 x = fold (ASSERT_EXPR_COND (t));
3178 if (x == boolean_false_node)
3180 error ("ASSERT_EXPR with an always-false condition");
3188 case GIMPLE_MODIFY_STMT:
3189 x = GIMPLE_STMT_OPERAND (t, 0);
3190 if (TREE_CODE (x) == BIT_FIELD_REF
3191 && is_gimple_reg (TREE_OPERAND (x, 0)))
3193 error ("GIMPLE register modified with BIT_FIELD_REF");
3202 bool old_side_effects;
3205 bool new_side_effects;
3207 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3208 dead PHIs that take the address of something. But if the PHI
3209 result is dead, the fact that it takes the address of anything
3210 is irrelevant. Because we can not tell from here if a PHI result
3211 is dead, we just skip this check for PHIs altogether. This means
3212 we may be missing "valid" checks, but what can you do?
3213 This was PR19217. */
3217 old_invariant = TREE_INVARIANT (t);
3218 old_constant = TREE_CONSTANT (t);
3219 old_side_effects = TREE_SIDE_EFFECTS (t);
3221 recompute_tree_invariant_for_addr_expr (t);
3222 new_invariant = TREE_INVARIANT (t);
3223 new_side_effects = TREE_SIDE_EFFECTS (t);
3224 new_constant = TREE_CONSTANT (t);
3226 if (old_invariant != new_invariant)
3228 error ("invariant not recomputed when ADDR_EXPR changed");
3232 if (old_constant != new_constant)
3234 error ("constant not recomputed when ADDR_EXPR changed");
3237 if (old_side_effects != new_side_effects)
3239 error ("side effects not recomputed when ADDR_EXPR changed");
3243 /* Skip any references (they will be checked when we recurse down the
3244 tree) and ensure that any variable used as a prefix is marked
3246 for (x = TREE_OPERAND (t, 0);
3247 handled_component_p (x);
3248 x = TREE_OPERAND (x, 0))
3251 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3253 if (!TREE_ADDRESSABLE (x))
3255 error ("address taken, but ADDRESSABLE bit not set");
3262 x = COND_EXPR_COND (t);
3263 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3265 error ("non-boolean used in condition");
3268 if (!is_gimple_condexpr (x))
3270 error ("invalid conditional operand");
3277 case FIX_TRUNC_EXPR:
3282 case NON_LVALUE_EXPR:
3283 case TRUTH_NOT_EXPR:
3284 CHECK_OP (0, "invalid operand to unary operator");
3291 case ARRAY_RANGE_REF:
3293 case VIEW_CONVERT_EXPR:
3294 /* We have a nest of references. Verify that each of the operands
3295 that determine where to reference is either a constant or a variable,
3296 verify that the base is valid, and then show we've already checked
3298 while (handled_component_p (t))
3300 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3301 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3302 else if (TREE_CODE (t) == ARRAY_REF
3303 || TREE_CODE (t) == ARRAY_RANGE_REF)
3305 CHECK_OP (1, "invalid array index");
3306 if (TREE_OPERAND (t, 2))
3307 CHECK_OP (2, "invalid array lower bound");
3308 if (TREE_OPERAND (t, 3))
3309 CHECK_OP (3, "invalid array stride");
3311 else if (TREE_CODE (t) == BIT_FIELD_REF)
3313 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3314 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3317 t = TREE_OPERAND (t, 0);
3320 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3322 error ("invalid reference prefix");
3334 case UNORDERED_EXPR:
3345 case TRUNC_DIV_EXPR:
3347 case FLOOR_DIV_EXPR:
3348 case ROUND_DIV_EXPR:
3349 case TRUNC_MOD_EXPR:
3351 case FLOOR_MOD_EXPR:
3352 case ROUND_MOD_EXPR:
3354 case EXACT_DIV_EXPR:
3364 CHECK_OP (0, "invalid operand to binary operator");
3365 CHECK_OP (1, "invalid operand to binary operator");
3369 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3382 /* Verify STMT, return true if STMT is not in GIMPLE form.
3383 TODO: Implement type checking. */
3386 verify_stmt (tree stmt, bool last_in_block)
3390 if (OMP_DIRECTIVE_P (stmt))
3392 /* OpenMP directives are validated by the FE and never operated
3393 on by the optimizers. Furthermore, OMP_FOR may contain
3394 non-gimple expressions when the main index variable has had
3395 its address taken. This does not affect the loop itself
3396 because the header of an OMP_FOR is merely used to determine
3397 how to setup the parallel iteration. */
3401 if (!is_gimple_stmt (stmt))
3403 error ("is not a valid GIMPLE statement");
3407 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3410 debug_generic_stmt (addr);
3414 /* If the statement is marked as part of an EH region, then it is
3415 expected that the statement could throw. Verify that when we
3416 have optimizations that simplify statements such that we prove
3417 that they cannot throw, that we update other data structures
3419 if (lookup_stmt_eh_region (stmt) >= 0)
3421 if (!tree_could_throw_p (stmt))
3423 error ("statement marked for throw, but doesn%'t");
3426 if (!last_in_block && tree_can_throw_internal (stmt))
3428 error ("statement marked for throw in middle of block");
3436 debug_generic_stmt (stmt);
3441 /* Return true when the T can be shared. */
3444 tree_node_can_be_shared (tree t)
3446 if (IS_TYPE_OR_DECL_P (t)
3447 || is_gimple_min_invariant (t)
3448 || TREE_CODE (t) == SSA_NAME
3449 || t == error_mark_node
3450 || TREE_CODE (t) == IDENTIFIER_NODE)
3453 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3456 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3457 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3458 || TREE_CODE (t) == COMPONENT_REF
3459 || TREE_CODE (t) == REALPART_EXPR
3460 || TREE_CODE (t) == IMAGPART_EXPR)
3461 t = TREE_OPERAND (t, 0);
3470 /* Called via walk_trees. Verify tree sharing. */
3473 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3475 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3477 if (tree_node_can_be_shared (*tp))
3479 *walk_subtrees = false;
3483 if (pointer_set_insert (visited, *tp))
3490 /* Helper function for verify_gimple_tuples. */
3493 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3494 void *data ATTRIBUTE_UNUSED)
3496 switch (TREE_CODE (*tp))
3499 error ("unexpected non-tuple");
3509 /* Verify that there are no trees that should have been converted to
3510 gimple tuples. Return true if T contains a node that should have
3511 been converted to a gimple tuple, but hasn't. */
3514 verify_gimple_tuples (tree t)
3516 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3519 static bool eh_error_found;
3521 verify_eh_throw_stmt_node (void **slot, void *data)
3523 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3524 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3526 if (!pointer_set_contains (visited, node->stmt))
3528 error ("Dead STMT in EH table");
3529 debug_generic_stmt (node->stmt);
3530 eh_error_found = true;
3535 /* Verify the GIMPLE statement chain. */
3541 block_stmt_iterator bsi;
3543 struct pointer_set_t *visited, *visited_stmts;
3546 timevar_push (TV_TREE_STMT_VERIFY);
3547 visited = pointer_set_create ();
3548 visited_stmts = pointer_set_create ();
3555 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3557 int phi_num_args = PHI_NUM_ARGS (phi);
3559 pointer_set_insert (visited_stmts, phi);
3560 if (bb_for_stmt (phi) != bb)
3562 error ("bb_for_stmt (phi) is set to a wrong basic block");
3566 for (i = 0; i < phi_num_args; i++)
3568 tree t = PHI_ARG_DEF (phi, i);
3571 /* Addressable variables do have SSA_NAMEs but they
3572 are not considered gimple values. */
3573 if (TREE_CODE (t) != SSA_NAME
3574 && TREE_CODE (t) != FUNCTION_DECL
3575 && !is_gimple_val (t))
3577 error ("PHI def is not a GIMPLE value");
3578 debug_generic_stmt (phi);
3579 debug_generic_stmt (t);
3583 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3586 debug_generic_stmt (addr);
3590 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3593 error ("incorrect sharing of tree nodes");
3594 debug_generic_stmt (phi);
3595 debug_generic_stmt (addr);
3601 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3603 tree stmt = bsi_stmt (bsi);
3605 pointer_set_insert (visited_stmts, stmt);
3606 err |= verify_gimple_tuples (stmt);
3608 if (bb_for_stmt (stmt) != bb)
3610 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3615 err |= verify_stmt (stmt, bsi_end_p (bsi));
3616 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3619 error ("incorrect sharing of tree nodes");
3620 debug_generic_stmt (stmt);
3621 debug_generic_stmt (addr);
3626 eh_error_found = false;
3627 if (get_eh_throw_stmt_table (cfun))
3628 htab_traverse (get_eh_throw_stmt_table (cfun),
3629 verify_eh_throw_stmt_node,
3632 if (err | eh_error_found)
3633 internal_error ("verify_stmts failed");
3635 pointer_set_destroy (visited);
3636 pointer_set_destroy (visited_stmts);
3637 verify_histograms ();
3638 timevar_pop (TV_TREE_STMT_VERIFY);
3642 /* Verifies that the flow information is OK. */
3645 tree_verify_flow_info (void)
3649 block_stmt_iterator bsi;
3654 if (ENTRY_BLOCK_PTR->stmt_list)
3656 error ("ENTRY_BLOCK has a statement list associated with it");
3660 if (EXIT_BLOCK_PTR->stmt_list)
3662 error ("EXIT_BLOCK has a statement list associated with it");
3666 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3667 if (e->flags & EDGE_FALLTHRU)
3669 error ("fallthru to exit from bb %d", e->src->index);
3675 bool found_ctrl_stmt = false;
3679 /* Skip labels on the start of basic block. */
3680 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3682 tree prev_stmt = stmt;
3684 stmt = bsi_stmt (bsi);
3686 if (TREE_CODE (stmt) != LABEL_EXPR)
3689 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3691 error ("nonlocal label ");
3692 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3693 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3698 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3701 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3702 fprintf (stderr, " to block does not match in bb %d",
3707 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3708 != current_function_decl)
3711 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3712 fprintf (stderr, " has incorrect context in bb %d",
3718 /* Verify that body of basic block BB is free of control flow. */
3719 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3721 tree stmt = bsi_stmt (bsi);
3723 if (found_ctrl_stmt)
3725 error ("control flow in the middle of basic block %d",
3730 if (stmt_ends_bb_p (stmt))
3731 found_ctrl_stmt = true;
3733 if (TREE_CODE (stmt) == LABEL_EXPR)
3736 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3737 fprintf (stderr, " in the middle of basic block %d", bb->index);
3742 bsi = bsi_last (bb);
3743 if (bsi_end_p (bsi))
3746 stmt = bsi_stmt (bsi);
3748 err |= verify_eh_edges (stmt);
3750 if (is_ctrl_stmt (stmt))
3752 FOR_EACH_EDGE (e, ei, bb->succs)
3753 if (e->flags & EDGE_FALLTHRU)
3755 error ("fallthru edge after a control statement in bb %d",
3761 if (TREE_CODE (stmt) != COND_EXPR)
3763 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3764 after anything else but if statement. */
3765 FOR_EACH_EDGE (e, ei, bb->succs)
3766 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3768 error ("true/false edge after a non-COND_EXPR in bb %d",
3774 switch (TREE_CODE (stmt))
3780 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3781 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3783 error ("structured COND_EXPR at the end of bb %d", bb->index);
3787 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3789 if (!true_edge || !false_edge
3790 || !(true_edge->flags & EDGE_TRUE_VALUE)
3791 || !(false_edge->flags & EDGE_FALSE_VALUE)
3792 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3793 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3794 || EDGE_COUNT (bb->succs) >= 3)
3796 error ("wrong outgoing edge flags at end of bb %d",
3801 if (!has_label_p (true_edge->dest,
3802 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3804 error ("%<then%> label does not match edge at end of bb %d",
3809 if (!has_label_p (false_edge->dest,
3810 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3812 error ("%<else%> label does not match edge at end of bb %d",
3820 if (simple_goto_p (stmt))
3822 error ("explicit goto at end of bb %d", bb->index);
3827 /* FIXME. We should double check that the labels in the
3828 destination blocks have their address taken. */
3829 FOR_EACH_EDGE (e, ei, bb->succs)
3830 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3831 | EDGE_FALSE_VALUE))
3832 || !(e->flags & EDGE_ABNORMAL))
3834 error ("wrong outgoing edge flags at end of bb %d",
3842 if (!single_succ_p (bb)
3843 || (single_succ_edge (bb)->flags
3844 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3845 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3847 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3850 if (single_succ (bb) != EXIT_BLOCK_PTR)
3852 error ("return edge does not point to exit in bb %d",
3865 vec = SWITCH_LABELS (stmt);
3866 n = TREE_VEC_LENGTH (vec);
3868 /* Mark all the destination basic blocks. */
3869 for (i = 0; i < n; ++i)
3871 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3872 basic_block label_bb = label_to_block (lab);
3874 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3875 label_bb->aux = (void *)1;
3878 /* Verify that the case labels are sorted. */
3879 prev = TREE_VEC_ELT (vec, 0);
3880 for (i = 1; i < n - 1; ++i)
3882 tree c = TREE_VEC_ELT (vec, i);
3885 error ("found default case not at end of case vector");
3889 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3891 error ("case labels not sorted: ");
3892 print_generic_expr (stderr, prev, 0);
3893 fprintf (stderr," is greater than ");
3894 print_generic_expr (stderr, c, 0);
3895 fprintf (stderr," but comes before it.\n");
3900 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3902 error ("no default case found at end of case vector");
3906 FOR_EACH_EDGE (e, ei, bb->succs)
3910 error ("extra outgoing edge %d->%d",
3911 bb->index, e->dest->index);
3914 e->dest->aux = (void *)2;
3915 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3916 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3918 error ("wrong outgoing edge flags at end of bb %d",
3924 /* Check that we have all of them. */
3925 for (i = 0; i < n; ++i)
3927 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3928 basic_block label_bb = label_to_block (lab);
3930 if (label_bb->aux != (void *)2)
3932 error ("missing edge %i->%i",
3933 bb->index, label_bb->index);
3938 FOR_EACH_EDGE (e, ei, bb->succs)
3939 e->dest->aux = (void *)0;
3946 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3947 verify_dominators (CDI_DOMINATORS);
3953 /* Updates phi nodes after creating a forwarder block joined
3954 by edge FALLTHRU. */
3957 tree_make_forwarder_block (edge fallthru)
3961 basic_block dummy, bb;
3962 tree phi, new_phi, var;
3964 dummy = fallthru->src;
3965 bb = fallthru->dest;
3967 if (single_pred_p (bb))
3970 /* If we redirected a branch we must create new PHI nodes at the
3972 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3974 var = PHI_RESULT (phi);
3975 new_phi = create_phi_node (var, bb);
3976 SSA_NAME_DEF_STMT (var) = new_phi;
3977 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3978 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3981 /* Ensure that the PHI node chain is in the same order. */
3982 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3984 /* Add the arguments we have stored on edges. */
3985 FOR_EACH_EDGE (e, ei, bb->preds)
3990 flush_pending_stmts (e);
3995 /* Return a non-special label in the head of basic block BLOCK.
3996 Create one if it doesn't exist. */
3999 tree_block_label (basic_block bb)
4001 block_stmt_iterator i, s = bsi_start (bb);
4005 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4007 stmt = bsi_stmt (i);
4008 if (TREE_CODE (stmt) != LABEL_EXPR)
4010 label = LABEL_EXPR_LABEL (stmt);
4011 if (!DECL_NONLOCAL (label))
4014 bsi_move_before (&i, &s);
4019 label = create_artificial_label ();
4020 stmt = build1 (LABEL_EXPR, void_type_node, label);
4021 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4026 /* Attempt to perform edge redirection by replacing a possibly complex
4027 jump instruction by a goto or by removing the jump completely.
4028 This can apply only if all edges now point to the same block. The
4029 parameters and return values are equivalent to
4030 redirect_edge_and_branch. */
4033 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4035 basic_block src = e->src;
4036 block_stmt_iterator b;
4039 /* We can replace or remove a complex jump only when we have exactly
4041 if (EDGE_COUNT (src->succs) != 2
4042 /* Verify that all targets will be TARGET. Specifically, the
4043 edge that is not E must also go to TARGET. */
4044 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4050 stmt = bsi_stmt (b);
4052 if (TREE_CODE (stmt) == COND_EXPR
4053 || TREE_CODE (stmt) == SWITCH_EXPR)
4055 bsi_remove (&b, true);
4056 e = ssa_redirect_edge (e, target);
4057 e->flags = EDGE_FALLTHRU;
4065 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4066 edge representing the redirected branch. */
4069 tree_redirect_edge_and_branch (edge e, basic_block dest)
4071 basic_block bb = e->src;
4072 block_stmt_iterator bsi;
4076 if (e->flags & EDGE_ABNORMAL)
4079 if (e->src != ENTRY_BLOCK_PTR
4080 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4083 if (e->dest == dest)
4086 label = tree_block_label (dest);
4088 bsi = bsi_last (bb);
4089 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4091 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4094 stmt = (e->flags & EDGE_TRUE_VALUE
4095 ? COND_EXPR_THEN (stmt)
4096 : COND_EXPR_ELSE (stmt));
4097 GOTO_DESTINATION (stmt) = label;
4101 /* No non-abnormal edges should lead from a non-simple goto, and
4102 simple ones should be represented implicitly. */
4107 tree cases = get_cases_for_edge (e, stmt);
4109 /* If we have a list of cases associated with E, then use it
4110 as it's a lot faster than walking the entire case vector. */
4113 edge e2 = find_edge (e->src, dest);
4120 CASE_LABEL (cases) = label;
4121 cases = TREE_CHAIN (cases);
4124 /* If there was already an edge in the CFG, then we need
4125 to move all the cases associated with E to E2. */
4128 tree cases2 = get_cases_for_edge (e2, stmt);
4130 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4131 TREE_CHAIN (cases2) = first;
4136 tree vec = SWITCH_LABELS (stmt);
4137 size_t i, n = TREE_VEC_LENGTH (vec);
4139 for (i = 0; i < n; i++)
4141 tree elt = TREE_VEC_ELT (vec, i);
4143 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4144 CASE_LABEL (elt) = label;
4152 bsi_remove (&bsi, true);
4153 e->flags |= EDGE_FALLTHRU;
4157 /* Otherwise it must be a fallthru edge, and we don't need to
4158 do anything besides redirecting it. */
4159 gcc_assert (e->flags & EDGE_FALLTHRU);
4163 /* Update/insert PHI nodes as necessary. */
4165 /* Now update the edges in the CFG. */
4166 e = ssa_redirect_edge (e, dest);
4171 /* Returns true if it is possible to remove edge E by redirecting
4172 it to the destination of the other edge from E->src. */
4175 tree_can_remove_branch_p (edge e)
4177 if (e->flags & EDGE_ABNORMAL)
4183 /* Simple wrapper, as we can always redirect fallthru edges. */
4186 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4188 e = tree_redirect_edge_and_branch (e, dest);
4195 /* Splits basic block BB after statement STMT (but at least after the
4196 labels). If STMT is NULL, BB is split just after the labels. */
4199 tree_split_block (basic_block bb, void *stmt)
4201 block_stmt_iterator bsi;
4202 tree_stmt_iterator tsi_tgt;
4208 new_bb = create_empty_bb (bb);
4210 /* Redirect the outgoing edges. */
4211 new_bb->succs = bb->succs;
4213 FOR_EACH_EDGE (e, ei, new_bb->succs)
4216 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4219 /* Move everything from BSI to the new basic block. */
4220 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4222 act = bsi_stmt (bsi);
4223 if (TREE_CODE (act) == LABEL_EXPR)
4236 if (bsi_end_p (bsi))
4239 /* Split the statement list - avoid re-creating new containers as this
4240 brings ugly quadratic memory consumption in the inliner.
4241 (We are still quadratic since we need to update stmt BB pointers,
4243 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4244 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4245 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4246 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4252 /* Moves basic block BB after block AFTER. */
4255 tree_move_block_after (basic_block bb, basic_block after)
4257 if (bb->prev_bb == after)
4261 link_block (bb, after);
4267 /* Return true if basic_block can be duplicated. */
4270 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4276 /* Create a duplicate of the basic block BB. NOTE: This does not
4277 preserve SSA form. */
4280 tree_duplicate_bb (basic_block bb)
4283 block_stmt_iterator bsi, bsi_tgt;
4286 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4288 /* Copy the PHI nodes. We ignore PHI node arguments here because
4289 the incoming edges have not been setup yet. */
4290 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4292 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4293 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4296 /* Keep the chain of PHI nodes in the same order so that they can be
4297 updated by ssa_redirect_edge. */
4298 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4300 bsi_tgt = bsi_start (new_bb);
4301 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4303 def_operand_p def_p;
4304 ssa_op_iter op_iter;
4308 stmt = bsi_stmt (bsi);
4309 if (TREE_CODE (stmt) == LABEL_EXPR)
4312 /* Create a new copy of STMT and duplicate STMT's virtual
4314 copy = unshare_expr (stmt);
4315 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4316 copy_virtual_operands (copy, stmt);
4317 region = lookup_stmt_eh_region (stmt);
4319 add_stmt_to_eh_region (copy, region);
4320 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4322 /* Create new names for all the definitions created by COPY and
4323 add replacement mappings for each new name. */
4324 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4325 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4332 /* Basic block BB_COPY was created by code duplication. Add phi node
4333 arguments for edges going out of BB_COPY. The blocks that were
4334 duplicated have BB_DUPLICATED set. */
4337 add_phi_args_after_copy_bb (basic_block bb_copy)
4339 basic_block bb, dest;
4342 tree phi, phi_copy, phi_next, def;
4344 bb = get_bb_original (bb_copy);
4346 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4348 if (!phi_nodes (e_copy->dest))
4351 if (e_copy->dest->flags & BB_DUPLICATED)
4352 dest = get_bb_original (e_copy->dest);
4354 dest = e_copy->dest;
4356 e = find_edge (bb, dest);
4359 /* During loop unrolling the target of the latch edge is copied.
4360 In this case we are not looking for edge to dest, but to
4361 duplicated block whose original was dest. */
4362 FOR_EACH_EDGE (e, ei, bb->succs)
4363 if ((e->dest->flags & BB_DUPLICATED)
4364 && get_bb_original (e->dest) == dest)
4367 gcc_assert (e != NULL);
4370 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4372 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4374 phi_next = PHI_CHAIN (phi);
4375 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4376 add_phi_arg (phi_copy, def, e_copy);
4381 /* Blocks in REGION_COPY array of length N_REGION were created by
4382 duplication of basic blocks. Add phi node arguments for edges
4383 going from these blocks. */
4386 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4390 for (i = 0; i < n_region; i++)
4391 region_copy[i]->flags |= BB_DUPLICATED;
4393 for (i = 0; i < n_region; i++)
4394 add_phi_args_after_copy_bb (region_copy[i]);
4396 for (i = 0; i < n_region; i++)
4397 region_copy[i]->flags &= ~BB_DUPLICATED;
4400 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4401 important exit edge EXIT. By important we mean that no SSA name defined
4402 inside region is live over the other exit edges of the region. All entry
4403 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4404 to the duplicate of the region. SSA form, dominance and loop information
4405 is updated. The new basic blocks are stored to REGION_COPY in the same
4406 order as they had in REGION, provided that REGION_COPY is not NULL.
4407 The function returns false if it is unable to copy the region,
4411 tree_duplicate_sese_region (edge entry, edge exit,
4412 basic_block *region, unsigned n_region,
4413 basic_block *region_copy)
4416 bool free_region_copy = false, copying_header = false;
4417 struct loop *loop = entry->dest->loop_father;
4421 int total_freq = 0, entry_freq = 0;
4422 gcov_type total_count = 0, entry_count = 0;
4424 if (!can_copy_bbs_p (region, n_region))
4427 /* Some sanity checking. Note that we do not check for all possible
4428 missuses of the functions. I.e. if you ask to copy something weird,
4429 it will work, but the state of structures probably will not be
4431 for (i = 0; i < n_region; i++)
4433 /* We do not handle subloops, i.e. all the blocks must belong to the
4435 if (region[i]->loop_father != loop)
4438 if (region[i] != entry->dest
4439 && region[i] == loop->header)
4445 /* In case the function is used for loop header copying (which is the primary
4446 use), ensure that EXIT and its copy will be new latch and entry edges. */
4447 if (loop->header == entry->dest)
4449 copying_header = true;
4450 loop->copy = loop->outer;
4452 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4455 for (i = 0; i < n_region; i++)
4456 if (region[i] != exit->src
4457 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4463 region_copy = XNEWVEC (basic_block, n_region);
4464 free_region_copy = true;
4467 gcc_assert (!need_ssa_update_p ());
4469 /* Record blocks outside the region that are dominated by something
4471 doms = XNEWVEC (basic_block, n_basic_blocks);
4472 initialize_original_copy_tables ();
4474 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4476 if (entry->dest->count)
4478 total_count = entry->dest->count;
4479 entry_count = entry->count;
4480 /* Fix up corner cases, to avoid division by zero or creation of negative
4482 if (entry_count > total_count)
4483 entry_count = total_count;
4487 total_freq = entry->dest->frequency;
4488 entry_freq = EDGE_FREQUENCY (entry);
4489 /* Fix up corner cases, to avoid division by zero or creation of negative
4491 if (total_freq == 0)
4493 else if (entry_freq > total_freq)
4494 entry_freq = total_freq;
4497 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4498 split_edge_bb_loc (entry));
4501 scale_bbs_frequencies_gcov_type (region, n_region,
4502 total_count - entry_count,
4504 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4509 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4511 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4516 loop->header = exit->dest;
4517 loop->latch = exit->src;
4520 /* Redirect the entry and add the phi node arguments. */
4521 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4522 gcc_assert (redirected != NULL);
4523 flush_pending_stmts (entry);
4525 /* Concerning updating of dominators: We must recount dominators
4526 for entry block and its copy. Anything that is outside of the
4527 region, but was dominated by something inside needs recounting as
4529 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4530 doms[n_doms++] = get_bb_original (entry->dest);
4531 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4534 /* Add the other PHI node arguments. */
4535 add_phi_args_after_copy (region_copy, n_region);
4537 /* Update the SSA web. */
4538 update_ssa (TODO_update_ssa);
4540 if (free_region_copy)
4543 free_original_copy_tables ();
4548 DEF_VEC_P(basic_block);
4549 DEF_VEC_ALLOC_P(basic_block,heap);
4552 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4553 adding blocks when the dominator traversal reaches EXIT. This
4554 function silently assumes that ENTRY strictly dominates EXIT. */
4557 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4558 VEC(basic_block,heap) **bbs_p)
4562 for (son = first_dom_son (CDI_DOMINATORS, entry);
4564 son = next_dom_son (CDI_DOMINATORS, son))
4566 VEC_safe_push (basic_block, heap, *bbs_p, son);
4568 gather_blocks_in_sese_region (son, exit, bbs_p);
4578 bitmap vars_to_remove;
4579 htab_t new_label_map;
4583 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4584 contained in *TP and change the DECL_CONTEXT of every local
4585 variable referenced in *TP. */
4588 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4590 struct move_stmt_d *p = (struct move_stmt_d *) data;
4594 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4595 TREE_BLOCK (t) = p->block;
4597 if (OMP_DIRECTIVE_P (t)
4598 && TREE_CODE (t) != OMP_RETURN
4599 && TREE_CODE (t) != OMP_CONTINUE)
4601 /* Do not remap variables inside OMP directives. Variables
4602 referenced in clauses and directive header belong to the
4603 parent function and should not be moved into the child
4605 bool save_remap_decls_p = p->remap_decls_p;
4606 p->remap_decls_p = false;
4609 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4611 p->remap_decls_p = save_remap_decls_p;
4613 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4615 if (TREE_CODE (t) == LABEL_DECL)
4617 if (p->new_label_map)
4619 struct tree_map in, *out;
4621 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4626 DECL_CONTEXT (t) = p->to_context;
4628 else if (p->remap_decls_p)
4630 DECL_CONTEXT (t) = p->to_context;
4632 if (TREE_CODE (t) == VAR_DECL)
4634 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4635 f->unexpanded_var_list
4636 = tree_cons (0, t, f->unexpanded_var_list);
4638 /* Mark T to be removed from the original function,
4639 otherwise it will be given a DECL_RTL when the
4640 original function is expanded. */
4641 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4645 else if (TYPE_P (t))
4652 /* Move basic block BB from function CFUN to function DEST_FN. The
4653 block is moved out of the original linked list and placed after
4654 block AFTER in the new list. Also, the block is removed from the
4655 original array of blocks and placed in DEST_FN's array of blocks.
4656 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4657 updated to reflect the moved edges.
4659 On exit, local variables that need to be removed from
4660 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4663 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4664 basic_block after, bool update_edge_count_p,
4665 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4667 struct control_flow_graph *cfg;
4670 block_stmt_iterator si;
4671 struct move_stmt_d d;
4672 unsigned old_len, new_len;
4674 /* Link BB to the new linked list. */
4675 move_block_after (bb, after);
4677 /* Update the edge count in the corresponding flowgraphs. */
4678 if (update_edge_count_p)
4679 FOR_EACH_EDGE (e, ei, bb->succs)
4681 cfun->cfg->x_n_edges--;
4682 dest_cfun->cfg->x_n_edges++;
4685 /* Remove BB from the original basic block array. */
4686 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4687 cfun->cfg->x_n_basic_blocks--;
4689 /* Grow DEST_CFUN's basic block array if needed. */
4690 cfg = dest_cfun->cfg;
4691 cfg->x_n_basic_blocks++;
4692 if (bb->index > cfg->x_last_basic_block)
4693 cfg->x_last_basic_block = bb->index;
4695 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4696 if ((unsigned) cfg->x_last_basic_block >= old_len)
4698 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4699 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4703 VEC_replace (basic_block, cfg->x_basic_block_info,
4704 cfg->x_last_basic_block, bb);
4706 /* The statements in BB need to be associated with a new TREE_BLOCK.
4707 Labels need to be associated with a new label-to-block map. */
4708 memset (&d, 0, sizeof (d));
4709 d.vars_to_remove = vars_to_remove;
4711 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4713 tree stmt = bsi_stmt (si);
4716 d.from_context = cfun->decl;
4717 d.to_context = dest_cfun->decl;
4718 d.remap_decls_p = true;
4719 d.new_label_map = new_label_map;
4720 if (TREE_BLOCK (stmt))
4721 d.block = DECL_INITIAL (dest_cfun->decl);
4723 walk_tree (&stmt, move_stmt_r, &d, NULL);
4725 if (TREE_CODE (stmt) == LABEL_EXPR)
4727 tree label = LABEL_EXPR_LABEL (stmt);
4728 int uid = LABEL_DECL_UID (label);
4730 gcc_assert (uid > -1);
4732 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4733 if (old_len <= (unsigned) uid)
4735 new_len = 3 * uid / 2;
4736 VEC_safe_grow_cleared (basic_block, gc,
4737 cfg->x_label_to_block_map, new_len);
4740 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4741 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4743 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4745 if (uid >= dest_cfun->last_label_uid)
4746 dest_cfun->last_label_uid = uid + 1;
4748 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4749 TREE_OPERAND (stmt, 0) =
4750 build_int_cst (NULL_TREE,
4751 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4754 region = lookup_stmt_eh_region (stmt);
4757 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4758 remove_stmt_from_eh_region (stmt);
4759 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4760 gimple_remove_stmt_histograms (cfun, stmt);
4765 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4766 the outermost EH region. Use REGION as the incoming base EH region. */
4769 find_outermost_region_in_block (struct function *src_cfun,
4770 basic_block bb, int region)
4772 block_stmt_iterator si;
4774 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4776 tree stmt = bsi_stmt (si);
4779 if (TREE_CODE (stmt) == RESX_EXPR)
4780 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4782 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4783 if (stmt_region > 0)
4786 region = stmt_region;
4787 else if (stmt_region != region)
4789 region = eh_region_outermost (src_cfun, stmt_region, region);
4790 gcc_assert (region != -1);
4799 new_label_mapper (tree decl, void *data)
4801 htab_t hash = (htab_t) data;
4805 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4807 m = xmalloc (sizeof (struct tree_map));
4808 m->hash = DECL_UID (decl);
4809 m->base.from = decl;
4810 m->to = create_artificial_label ();
4811 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4813 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4814 gcc_assert (*slot == NULL);
4821 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4822 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4823 single basic block in the original CFG and the new basic block is
4824 returned. DEST_CFUN must not have a CFG yet.
4826 Note that the region need not be a pure SESE region. Blocks inside
4827 the region may contain calls to abort/exit. The only restriction
4828 is that ENTRY_BB should be the only entry point and it must
4831 All local variables referenced in the region are assumed to be in
4832 the corresponding BLOCK_VARS and unexpanded variable lists
4833 associated with DEST_CFUN. */
4836 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4837 basic_block exit_bb)
4839 VEC(basic_block,heap) *bbs;
4840 basic_block after, bb, *entry_pred, *exit_succ;
4841 struct function *saved_cfun;
4842 int *entry_flag, *exit_flag, eh_offset;
4843 unsigned i, num_entry_edges, num_exit_edges;
4846 bitmap vars_to_remove;
4847 htab_t new_label_map;
4851 /* Collect all the blocks in the region. Manually add ENTRY_BB
4852 because it won't be added by dfs_enumerate_from. */
4853 calculate_dominance_info (CDI_DOMINATORS);
4855 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4857 gcc_assert (entry_bb != exit_bb
4859 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4862 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4863 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4865 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4866 the predecessor edges to ENTRY_BB and the successor edges to
4867 EXIT_BB so that we can re-attach them to the new basic block that
4868 will replace the region. */
4869 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4870 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4871 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4873 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4875 entry_flag[i] = e->flags;
4876 entry_pred[i++] = e->src;
4882 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4883 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4884 sizeof (basic_block));
4885 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4887 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4889 exit_flag[i] = e->flags;
4890 exit_succ[i++] = e->dest;
4901 /* Switch context to the child function to initialize DEST_FN's CFG. */
4902 gcc_assert (dest_cfun->cfg == NULL);
4905 init_empty_tree_cfg ();
4907 /* Initialize EH information for the new function. */
4909 new_label_map = NULL;
4914 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4915 region = find_outermost_region_in_block (saved_cfun, bb, region);
4917 init_eh_for_function ();
4920 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4921 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4922 new_label_map, region, 0);
4928 /* Move blocks from BBS into DEST_CFUN. */
4929 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4930 after = dest_cfun->cfg->x_entry_block_ptr;
4931 vars_to_remove = BITMAP_ALLOC (NULL);
4932 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4934 /* No need to update edge counts on the last block. It has
4935 already been updated earlier when we detached the region from
4936 the original CFG. */
4937 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4938 new_label_map, eh_offset);
4943 htab_delete (new_label_map);
4945 /* Remove the variables marked in VARS_TO_REMOVE from
4946 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4947 DECL_RTL in the context of CFUN. */
4948 if (!bitmap_empty_p (vars_to_remove))
4952 for (p = &cfun->unexpanded_var_list; *p; )
4954 tree var = TREE_VALUE (*p);
4955 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4957 *p = TREE_CHAIN (*p);
4961 p = &TREE_CHAIN (*p);
4965 BITMAP_FREE (vars_to_remove);
4967 /* Rewire the entry and exit blocks. The successor to the entry
4968 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4969 the child function. Similarly, the predecessor of DEST_FN's
4970 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4971 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4972 various CFG manipulation function get to the right CFG.
4974 FIXME, this is silly. The CFG ought to become a parameter to
4977 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4979 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4982 /* Back in the original function, the SESE region has disappeared,
4983 create a new basic block in its place. */
4984 bb = create_empty_bb (entry_pred[0]);
4985 for (i = 0; i < num_entry_edges; i++)
4986 make_edge (entry_pred[i], bb, entry_flag[i]);
4988 for (i = 0; i < num_exit_edges; i++)
4989 make_edge (bb, exit_succ[i], exit_flag[i]);
4998 free_dominance_info (CDI_DOMINATORS);
4999 free_dominance_info (CDI_POST_DOMINATORS);
5000 VEC_free (basic_block, heap, bbs);
5006 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5009 dump_function_to_file (tree fn, FILE *file, int flags)
5011 tree arg, vars, var;
5012 struct function *dsf;
5013 bool ignore_topmost_bind = false, any_var = false;
5016 struct function *saved_cfun;
5018 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5020 arg = DECL_ARGUMENTS (fn);
5023 print_generic_expr (file, arg, dump_flags);
5024 if (TREE_CHAIN (arg))
5025 fprintf (file, ", ");
5026 arg = TREE_CHAIN (arg);
5028 fprintf (file, ")\n");
5030 dsf = DECL_STRUCT_FUNCTION (fn);
5031 if (dsf && (flags & TDF_DETAILS))
5032 dump_eh_tree (file, dsf);
5034 if (flags & TDF_RAW)
5036 dump_node (fn, TDF_SLIM | flags, file);
5040 /* Switch CFUN to point to FN. */
5042 cfun = DECL_STRUCT_FUNCTION (fn);
5044 /* When GIMPLE is lowered, the variables are no longer available in
5045 BIND_EXPRs, so display them separately. */
5046 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5048 ignore_topmost_bind = true;
5050 fprintf (file, "{\n");
5051 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5053 var = TREE_VALUE (vars);
5055 print_generic_decl (file, var, flags);
5056 fprintf (file, "\n");
5062 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5064 /* Make a CFG based dump. */
5065 check_bb_profile (ENTRY_BLOCK_PTR, file);
5066 if (!ignore_topmost_bind)
5067 fprintf (file, "{\n");
5069 if (any_var && n_basic_blocks)
5070 fprintf (file, "\n");
5073 dump_generic_bb (file, bb, 2, flags);
5075 fprintf (file, "}\n");
5076 check_bb_profile (EXIT_BLOCK_PTR, file);
5082 /* Make a tree based dump. */
5083 chain = DECL_SAVED_TREE (fn);
5085 if (chain && TREE_CODE (chain) == BIND_EXPR)
5087 if (ignore_topmost_bind)
5089 chain = BIND_EXPR_BODY (chain);
5097 if (!ignore_topmost_bind)
5098 fprintf (file, "{\n");
5103 fprintf (file, "\n");
5105 print_generic_stmt_indented (file, chain, flags, indent);
5106 if (ignore_topmost_bind)
5107 fprintf (file, "}\n");
5110 fprintf (file, "\n\n");
5117 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5120 debug_function (tree fn, int flags)
5122 dump_function_to_file (fn, stderr, flags);
5126 /* Pretty print of the loops intermediate representation. */
5127 static void print_loop (FILE *, struct loop *, int);
5128 static void print_pred_bbs (FILE *, basic_block bb);
5129 static void print_succ_bbs (FILE *, basic_block bb);
5132 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5135 print_pred_bbs (FILE *file, basic_block bb)
5140 FOR_EACH_EDGE (e, ei, bb->preds)
5141 fprintf (file, "bb_%d ", e->src->index);
5145 /* Print on FILE the indexes for the successors of basic_block BB. */
5148 print_succ_bbs (FILE *file, basic_block bb)
5153 FOR_EACH_EDGE (e, ei, bb->succs)
5154 fprintf (file, "bb_%d ", e->dest->index);
5158 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5161 print_loop (FILE *file, struct loop *loop, int indent)
5169 s_indent = (char *) alloca ((size_t) indent + 1);
5170 memset ((void *) s_indent, ' ', (size_t) indent);
5171 s_indent[indent] = '\0';
5173 /* Print the loop's header. */
5174 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5176 /* Print the loop's body. */
5177 fprintf (file, "%s{\n", s_indent);
5179 if (bb->loop_father == loop)
5181 /* Print the basic_block's header. */
5182 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5183 print_pred_bbs (file, bb);
5184 fprintf (file, "}, succs = {");
5185 print_succ_bbs (file, bb);
5186 fprintf (file, "})\n");
5188 /* Print the basic_block's body. */
5189 fprintf (file, "%s {\n", s_indent);
5190 tree_dump_bb (bb, file, indent + 4);
5191 fprintf (file, "%s }\n", s_indent);
5194 print_loop (file, loop->inner, indent + 2);
5195 fprintf (file, "%s}\n", s_indent);
5196 print_loop (file, loop->next, indent);
5200 /* Follow a CFG edge from the entry point of the program, and on entry
5201 of a loop, pretty print the loop structure on FILE. */
5204 print_loop_ir (FILE *file)
5208 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5209 if (bb && bb->loop_father)
5210 print_loop (file, bb->loop_father, 0);
5214 /* Debugging loops structure at tree level. */
5217 debug_loop_ir (void)
5219 print_loop_ir (stderr);
5223 /* Return true if BB ends with a call, possibly followed by some
5224 instructions that must stay with the call. Return false,
5228 tree_block_ends_with_call_p (basic_block bb)
5230 block_stmt_iterator bsi = bsi_last (bb);
5231 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5235 /* Return true if BB ends with a conditional branch. Return false,
5239 tree_block_ends_with_condjump_p (basic_block bb)
5241 tree stmt = last_stmt (bb);
5242 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5246 /* Return true if we need to add fake edge to exit at statement T.
5247 Helper function for tree_flow_call_edges_add. */
5250 need_fake_edge_p (tree t)
5254 /* NORETURN and LONGJMP calls already have an edge to exit.
5255 CONST and PURE calls do not need one.
5256 We don't currently check for CONST and PURE here, although
5257 it would be a good idea, because those attributes are
5258 figured out from the RTL in mark_constant_function, and
5259 the counter incrementation code from -fprofile-arcs
5260 leads to different results from -fbranch-probabilities. */
5261 call = get_call_expr_in (t);
5263 && !(call_expr_flags (call) & ECF_NORETURN))
5266 if (TREE_CODE (t) == ASM_EXPR
5267 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5274 /* Add fake edges to the function exit for any non constant and non
5275 noreturn calls, volatile inline assembly in the bitmap of blocks
5276 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5277 the number of blocks that were split.
5279 The goal is to expose cases in which entering a basic block does
5280 not imply that all subsequent instructions must be executed. */
5283 tree_flow_call_edges_add (sbitmap blocks)
5286 int blocks_split = 0;
5287 int last_bb = last_basic_block;
5288 bool check_last_block = false;
5290 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5294 check_last_block = true;
5296 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5298 /* In the last basic block, before epilogue generation, there will be
5299 a fallthru edge to EXIT. Special care is required if the last insn
5300 of the last basic block is a call because make_edge folds duplicate
5301 edges, which would result in the fallthru edge also being marked
5302 fake, which would result in the fallthru edge being removed by
5303 remove_fake_edges, which would result in an invalid CFG.
5305 Moreover, we can't elide the outgoing fake edge, since the block
5306 profiler needs to take this into account in order to solve the minimal
5307 spanning tree in the case that the call doesn't return.
5309 Handle this by adding a dummy instruction in a new last basic block. */
5310 if (check_last_block)
5312 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5313 block_stmt_iterator bsi = bsi_last (bb);
5315 if (!bsi_end_p (bsi))
5318 if (t && need_fake_edge_p (t))
5322 e = find_edge (bb, EXIT_BLOCK_PTR);
5325 bsi_insert_on_edge (e, build_empty_stmt ());
5326 bsi_commit_edge_inserts ();
5331 /* Now add fake edges to the function exit for any non constant
5332 calls since there is no way that we can determine if they will
5334 for (i = 0; i < last_bb; i++)
5336 basic_block bb = BASIC_BLOCK (i);
5337 block_stmt_iterator bsi;
5338 tree stmt, last_stmt;
5343 if (blocks && !TEST_BIT (blocks, i))
5346 bsi = bsi_last (bb);
5347 if (!bsi_end_p (bsi))
5349 last_stmt = bsi_stmt (bsi);
5352 stmt = bsi_stmt (bsi);
5353 if (need_fake_edge_p (stmt))
5356 /* The handling above of the final block before the
5357 epilogue should be enough to verify that there is
5358 no edge to the exit block in CFG already.
5359 Calling make_edge in such case would cause us to
5360 mark that edge as fake and remove it later. */
5361 #ifdef ENABLE_CHECKING
5362 if (stmt == last_stmt)
5364 e = find_edge (bb, EXIT_BLOCK_PTR);
5365 gcc_assert (e == NULL);
5369 /* Note that the following may create a new basic block
5370 and renumber the existing basic blocks. */
5371 if (stmt != last_stmt)
5373 e = split_block (bb, stmt);
5377 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5381 while (!bsi_end_p (bsi));
5386 verify_flow_info ();
5388 return blocks_split;
5391 /* Purge dead abnormal call edges from basic block BB. */
5394 tree_purge_dead_abnormal_call_edges (basic_block bb)
5396 bool changed = tree_purge_dead_eh_edges (bb);
5398 if (current_function_has_nonlocal_label)
5400 tree stmt = last_stmt (bb);
5404 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5405 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5407 if (e->flags & EDGE_ABNORMAL)
5416 /* See tree_purge_dead_eh_edges below. */
5418 free_dominance_info (CDI_DOMINATORS);
5424 /* Purge dead EH edges from basic block BB. */
5427 tree_purge_dead_eh_edges (basic_block bb)
5429 bool changed = false;
5432 tree stmt = last_stmt (bb);
5434 if (stmt && tree_can_throw_internal (stmt))
5437 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5439 if (e->flags & EDGE_EH)
5448 /* Removal of dead EH edges might change dominators of not
5449 just immediate successors. E.g. when bb1 is changed so that
5450 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5451 eh edges purged by this function in:
5463 idom(bb5) must be recomputed. For now just free the dominance
5466 free_dominance_info (CDI_DOMINATORS);
5472 tree_purge_all_dead_eh_edges (bitmap blocks)
5474 bool changed = false;
5478 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5480 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5486 /* This function is called whenever a new edge is created or
5490 tree_execute_on_growing_pred (edge e)
5492 basic_block bb = e->dest;
5495 reserve_phi_args_for_new_edge (bb);
5498 /* This function is called immediately before edge E is removed from
5499 the edge vector E->dest->preds. */
5502 tree_execute_on_shrinking_pred (edge e)
5504 if (phi_nodes (e->dest))
5505 remove_phi_args (e);
5508 /*---------------------------------------------------------------------------
5509 Helper functions for Loop versioning
5510 ---------------------------------------------------------------------------*/
5512 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5513 of 'first'. Both of them are dominated by 'new_head' basic block. When
5514 'new_head' was created by 'second's incoming edge it received phi arguments
5515 on the edge by split_edge(). Later, additional edge 'e' was created to
5516 connect 'new_head' and 'first'. Now this routine adds phi args on this
5517 additional edge 'e' that new_head to second edge received as part of edge
5522 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5523 basic_block new_head, edge e)
5526 edge e2 = find_edge (new_head, second);
5528 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5529 edge, we should always have an edge from NEW_HEAD to SECOND. */
5530 gcc_assert (e2 != NULL);
5532 /* Browse all 'second' basic block phi nodes and add phi args to
5533 edge 'e' for 'first' head. PHI args are always in correct order. */
5535 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5537 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5539 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5540 add_phi_arg (phi1, def, e);
5544 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5545 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5546 the destination of the ELSE part. */
5548 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5549 basic_block cond_bb, void *cond_e)
5551 block_stmt_iterator bsi;
5552 tree goto1 = NULL_TREE;
5553 tree goto2 = NULL_TREE;
5554 tree new_cond_expr = NULL_TREE;
5555 tree cond_expr = (tree) cond_e;
5558 /* Build new conditional expr */
5559 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5560 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5561 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5563 /* Add new cond in cond_bb. */
5564 bsi = bsi_start (cond_bb);
5565 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5566 /* Adjust edges appropriately to connect new head with first head
5567 as well as second head. */
5568 e0 = single_succ_edge (cond_bb);
5569 e0->flags &= ~EDGE_FALLTHRU;
5570 e0->flags |= EDGE_FALSE_VALUE;
5573 struct cfg_hooks tree_cfg_hooks = {
5575 tree_verify_flow_info,
5576 tree_dump_bb, /* dump_bb */
5577 create_bb, /* create_basic_block */
5578 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5579 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5580 tree_can_remove_branch_p, /* can_remove_branch_p */
5581 remove_bb, /* delete_basic_block */
5582 tree_split_block, /* split_block */
5583 tree_move_block_after, /* move_block_after */
5584 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5585 tree_merge_blocks, /* merge_blocks */
5586 tree_predict_edge, /* predict_edge */
5587 tree_predicted_by_p, /* predicted_by_p */
5588 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5589 tree_duplicate_bb, /* duplicate_block */
5590 tree_split_edge, /* split_edge */
5591 tree_make_forwarder_block, /* make_forward_block */
5592 NULL, /* tidy_fallthru_edge */
5593 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5594 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5595 tree_flow_call_edges_add, /* flow_call_edges_add */
5596 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5597 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5598 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5599 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5600 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5601 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5602 flush_pending_stmts /* flush_pending_stmts */
5606 /* Split all critical edges. */
5609 split_critical_edges (void)
5615 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5616 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5617 mappings around the calls to split_edge. */
5618 start_recording_case_labels ();
5621 FOR_EACH_EDGE (e, ei, bb->succs)
5622 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5627 end_recording_case_labels ();
5631 struct tree_opt_pass pass_split_crit_edges =
5633 "crited", /* name */
5635 split_critical_edges, /* execute */
5638 0, /* static_pass_number */
5639 TV_TREE_SPLIT_EDGES, /* tv_id */
5640 PROP_cfg, /* properties required */
5641 PROP_no_crit_edges, /* properties_provided */
5642 0, /* properties_destroyed */
5643 0, /* todo_flags_start */
5644 TODO_dump_func, /* todo_flags_finish */
5649 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5650 a temporary, make sure and register it to be renamed if necessary,
5651 and finally return the temporary. Put the statements to compute
5652 EXP before the current statement in BSI. */
5655 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5657 tree t, new_stmt, orig_stmt;
5659 if (is_gimple_val (exp))
5662 t = make_rename_temp (type, NULL);
5663 new_stmt = build_gimple_modify_stmt (t, exp);
5665 orig_stmt = bsi_stmt (*bsi);
5666 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5667 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5669 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5670 if (gimple_in_ssa_p (cfun))
5671 mark_symbols_for_renaming (new_stmt);
5676 /* Build a ternary operation and gimplify it. Emit code before BSI.
5677 Return the gimple_val holding the result. */
5680 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5681 tree type, tree a, tree b, tree c)
5685 ret = fold_build3 (code, type, a, b, c);
5688 return gimplify_val (bsi, type, ret);
5691 /* Build a binary operation and gimplify it. Emit code before BSI.
5692 Return the gimple_val holding the result. */
5695 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5696 tree type, tree a, tree b)
5700 ret = fold_build2 (code, type, a, b);
5703 return gimplify_val (bsi, type, ret);
5706 /* Build a unary operation and gimplify it. Emit code before BSI.
5707 Return the gimple_val holding the result. */
5710 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5715 ret = fold_build1 (code, type, a);
5718 return gimplify_val (bsi, type, ret);
5723 /* Emit return warnings. */
5726 execute_warn_function_return (void)
5728 #ifdef USE_MAPPED_LOCATION
5729 source_location location;
5737 /* If we have a path to EXIT, then we do return. */
5738 if (TREE_THIS_VOLATILE (cfun->decl)
5739 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5741 #ifdef USE_MAPPED_LOCATION
5742 location = UNKNOWN_LOCATION;
5746 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5748 last = last_stmt (e->src);
5749 if (TREE_CODE (last) == RETURN_EXPR
5750 #ifdef USE_MAPPED_LOCATION
5751 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5753 && (locus = EXPR_LOCUS (last)) != NULL)
5757 #ifdef USE_MAPPED_LOCATION
5758 if (location == UNKNOWN_LOCATION)
5759 location = cfun->function_end_locus;
5760 warning (0, "%H%<noreturn%> function does return", &location);
5763 locus = &cfun->function_end_locus;
5764 warning (0, "%H%<noreturn%> function does return", locus);
5768 /* If we see "return;" in some basic block, then we do reach the end
5769 without returning a value. */
5770 else if (warn_return_type
5771 && !TREE_NO_WARNING (cfun->decl)
5772 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5773 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5775 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5777 tree last = last_stmt (e->src);
5778 if (TREE_CODE (last) == RETURN_EXPR
5779 && TREE_OPERAND (last, 0) == NULL
5780 && !TREE_NO_WARNING (last))
5782 #ifdef USE_MAPPED_LOCATION
5783 location = EXPR_LOCATION (last);
5784 if (location == UNKNOWN_LOCATION)
5785 location = cfun->function_end_locus;
5786 warning (0, "%Hcontrol reaches end of non-void function", &location);
5788 locus = EXPR_LOCUS (last);
5790 locus = &cfun->function_end_locus;
5791 warning (0, "%Hcontrol reaches end of non-void function", locus);
5793 TREE_NO_WARNING (cfun->decl) = 1;
5802 /* Given a basic block B which ends with a conditional and has
5803 precisely two successors, determine which of the edges is taken if
5804 the conditional is true and which is taken if the conditional is
5805 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5808 extract_true_false_edges_from_block (basic_block b,
5812 edge e = EDGE_SUCC (b, 0);
5814 if (e->flags & EDGE_TRUE_VALUE)
5817 *false_edge = EDGE_SUCC (b, 1);
5822 *true_edge = EDGE_SUCC (b, 1);
5826 struct tree_opt_pass pass_warn_function_return =
5830 execute_warn_function_return, /* execute */
5833 0, /* static_pass_number */
5835 PROP_cfg, /* properties_required */
5836 0, /* properties_provided */
5837 0, /* properties_destroyed */
5838 0, /* todo_flags_start */
5839 0, /* todo_flags_finish */
5843 /* Emit noreturn warnings. */
5846 execute_warn_function_noreturn (void)
5848 if (warn_missing_noreturn
5849 && !TREE_THIS_VOLATILE (cfun->decl)
5850 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5851 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5852 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5853 "for attribute %<noreturn%>",
5858 struct tree_opt_pass pass_warn_function_noreturn =
5862 execute_warn_function_noreturn, /* execute */
5865 0, /* static_pass_number */
5867 PROP_cfg, /* properties_required */
5868 0, /* properties_provided */
5869 0, /* properties_destroyed */
5870 0, /* todo_flags_start */
5871 0, /* todo_flags_finish */