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->il.tree = GGC_CNEW (struct tree_bb_info);
372 set_bb_stmt_list (bb, h ? (tree) h : alloc_stmt_list ());
374 /* Add the new block to the linked list of blocks. */
375 link_block (bb, after);
377 /* Grow the basic block array if needed. */
378 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
380 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
381 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
384 /* Add the newly created block to the array. */
385 SET_BASIC_BLOCK (last_basic_block, bb);
394 /*---------------------------------------------------------------------------
396 ---------------------------------------------------------------------------*/
398 /* Fold COND_EXPR_COND of each COND_EXPR. */
401 fold_cond_expr_cond (void)
407 tree stmt = last_stmt (bb);
410 && TREE_CODE (stmt) == COND_EXPR)
415 fold_defer_overflow_warnings ();
416 cond = fold (COND_EXPR_COND (stmt));
417 zerop = integer_zerop (cond);
418 onep = integer_onep (cond);
419 fold_undefer_overflow_warnings (((zerop || onep)
420 && !TREE_NO_WARNING (stmt)),
422 WARN_STRICT_OVERFLOW_CONDITIONAL);
424 COND_EXPR_COND (stmt) = boolean_false_node;
426 COND_EXPR_COND (stmt) = boolean_true_node;
431 /* Join all the blocks in the flowgraph. */
437 struct omp_region *cur_region = NULL;
439 /* Create an edge from entry to the first block with executable
441 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
443 /* Traverse the basic block array placing edges. */
446 tree last = last_stmt (bb);
451 enum tree_code code = TREE_CODE (last);
455 make_goto_expr_edges (bb);
459 make_edge (bb, EXIT_BLOCK_PTR, 0);
463 make_cond_expr_edges (bb);
467 make_switch_expr_edges (bb);
471 make_eh_edges (last);
476 /* If this function receives a nonlocal goto, then we need to
477 make edges from this call site to all the nonlocal goto
479 if (tree_can_make_abnormal_goto (last))
480 make_abnormal_goto_edges (bb, true);
482 /* If this statement has reachable exception handlers, then
483 create abnormal edges to them. */
484 make_eh_edges (last);
486 /* Some calls are known not to return. */
487 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
493 case GIMPLE_MODIFY_STMT:
494 if (is_ctrl_altering_stmt (last))
496 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
497 the CALL_EXPR may have an abnormal edge. Search the RHS
498 for this case and create any required edges. */
499 if (tree_can_make_abnormal_goto (last))
500 make_abnormal_goto_edges (bb, true);
502 make_eh_edges (last);
514 cur_region = new_omp_region (bb, code, cur_region);
519 cur_region = new_omp_region (bb, code, cur_region);
524 /* In the case of an OMP_SECTION, the edge will go somewhere
525 other than the next block. This will be created later. */
526 cur_region->exit = bb;
527 fallthru = cur_region->type != OMP_SECTION;
528 cur_region = cur_region->outer;
532 cur_region->cont = bb;
533 switch (cur_region->type)
536 /* ??? Technically there should be a some sort of loopback
537 edge here, but it goes to a block that doesn't exist yet,
538 and without it, updating the ssa form would be a real
539 bear. Fortunately, we don't yet do ssa before expanding
544 /* Wire up the edges into and out of the nested sections. */
545 /* ??? Similarly wrt loopback. */
547 struct omp_region *i;
548 for (i = cur_region->inner; i ; i = i->next)
550 gcc_assert (i->type == OMP_SECTION);
551 make_edge (cur_region->entry, i->entry, 0);
552 make_edge (i->exit, bb, EDGE_FALLTHRU);
564 gcc_assert (!stmt_ends_bb_p (last));
572 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
578 /* Fold COND_EXPR_COND of each COND_EXPR. */
579 fold_cond_expr_cond ();
583 /* Create the edges for a COND_EXPR starting at block BB.
584 At this point, both clauses must contain only simple gotos. */
587 make_cond_expr_edges (basic_block bb)
589 tree entry = last_stmt (bb);
590 basic_block then_bb, else_bb;
591 tree then_label, else_label;
595 gcc_assert (TREE_CODE (entry) == COND_EXPR);
597 /* Entry basic blocks for each component. */
598 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
599 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
600 then_bb = label_to_block (then_label);
601 else_bb = label_to_block (else_label);
603 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
604 #ifdef USE_MAPPED_LOCATION
605 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
607 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
609 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
612 #ifdef USE_MAPPED_LOCATION
613 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
615 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
619 /* We do not need the gotos anymore. */
620 COND_EXPR_THEN (entry) = NULL_TREE;
621 COND_EXPR_ELSE (entry) = NULL_TREE;
625 /* Called for each element in the hash table (P) as we delete the
626 edge to cases hash table.
628 Clear all the TREE_CHAINs to prevent problems with copying of
629 SWITCH_EXPRs and structure sharing rules, then free the hash table
633 edge_to_cases_cleanup (void *key ATTRIBUTE_UNUSED, void **value,
634 void *data ATTRIBUTE_UNUSED)
638 for (t = (tree) *value; t; t = next)
640 next = TREE_CHAIN (t);
641 TREE_CHAIN (t) = NULL;
648 /* Start recording information mapping edges to case labels. */
651 start_recording_case_labels (void)
653 gcc_assert (edge_to_cases == NULL);
654 edge_to_cases = pointer_map_create ();
657 /* Return nonzero if we are recording information for case labels. */
660 recording_case_labels_p (void)
662 return (edge_to_cases != NULL);
665 /* Stop recording information mapping edges to case labels and
666 remove any information we have recorded. */
668 end_recording_case_labels (void)
670 pointer_map_traverse (edge_to_cases, edge_to_cases_cleanup, NULL);
671 pointer_map_destroy (edge_to_cases);
672 edge_to_cases = NULL;
675 /* If we are inside a {start,end}_recording_cases block, then return
676 a chain of CASE_LABEL_EXPRs from T which reference E.
678 Otherwise return NULL. */
681 get_cases_for_edge (edge e, tree t)
687 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
688 chains available. Return NULL so the caller can detect this case. */
689 if (!recording_case_labels_p ())
692 slot = pointer_map_contains (edge_to_cases, e);
696 /* If we did not find E in the hash table, then this must be the first
697 time we have been queried for information about E & T. Add all the
698 elements from T to the hash table then perform the query again. */
700 vec = SWITCH_LABELS (t);
701 n = TREE_VEC_LENGTH (vec);
702 for (i = 0; i < n; i++)
704 tree elt = TREE_VEC_ELT (vec, i);
705 tree lab = CASE_LABEL (elt);
706 basic_block label_bb = label_to_block (lab);
707 edge this_edge = find_edge (e->src, label_bb);
709 /* Add it to the chain of CASE_LABEL_EXPRs referencing E, or create
711 slot = pointer_map_insert (edge_to_cases, this_edge);
712 TREE_CHAIN (elt) = (tree) *slot;
716 return (tree) *pointer_map_contains (edge_to_cases, e);
719 /* Create the edges for a SWITCH_EXPR starting at block BB.
720 At this point, the switch body has been lowered and the
721 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
724 make_switch_expr_edges (basic_block bb)
726 tree entry = last_stmt (bb);
730 vec = SWITCH_LABELS (entry);
731 n = TREE_VEC_LENGTH (vec);
733 for (i = 0; i < n; ++i)
735 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
736 basic_block label_bb = label_to_block (lab);
737 make_edge (bb, label_bb, 0);
742 /* Return the basic block holding label DEST. */
745 label_to_block_fn (struct function *ifun, tree dest)
747 int uid = LABEL_DECL_UID (dest);
749 /* We would die hard when faced by an undefined label. Emit a label to
750 the very first basic block. This will hopefully make even the dataflow
751 and undefined variable warnings quite right. */
752 if ((errorcount || sorrycount) && uid < 0)
754 block_stmt_iterator bsi =
755 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
758 stmt = build1 (LABEL_EXPR, void_type_node, dest);
759 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
760 uid = LABEL_DECL_UID (dest);
762 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
763 <= (unsigned int) uid)
765 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
768 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
769 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
772 make_abnormal_goto_edges (basic_block bb, bool for_call)
774 basic_block target_bb;
775 block_stmt_iterator bsi;
777 FOR_EACH_BB (target_bb)
778 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
780 tree target = bsi_stmt (bsi);
782 if (TREE_CODE (target) != LABEL_EXPR)
785 target = LABEL_EXPR_LABEL (target);
787 /* Make an edge to every label block that has been marked as a
788 potential target for a computed goto or a non-local goto. */
789 if ((FORCED_LABEL (target) && !for_call)
790 || (DECL_NONLOCAL (target) && for_call))
792 make_edge (bb, target_bb, EDGE_ABNORMAL);
798 /* Create edges for a goto statement at block BB. */
801 make_goto_expr_edges (basic_block bb)
803 block_stmt_iterator last = bsi_last (bb);
804 tree goto_t = bsi_stmt (last);
806 /* A simple GOTO creates normal edges. */
807 if (simple_goto_p (goto_t))
809 tree dest = GOTO_DESTINATION (goto_t);
810 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
811 #ifdef USE_MAPPED_LOCATION
812 e->goto_locus = EXPR_LOCATION (goto_t);
814 e->goto_locus = EXPR_LOCUS (goto_t);
816 bsi_remove (&last, true);
820 /* A computed GOTO creates abnormal edges. */
821 make_abnormal_goto_edges (bb, false);
825 /*---------------------------------------------------------------------------
827 ---------------------------------------------------------------------------*/
829 /* Cleanup useless labels in basic blocks. This is something we wish
830 to do early because it allows us to group case labels before creating
831 the edges for the CFG, and it speeds up block statement iterators in
833 We only run this pass once, running it more than once is probably not
836 /* A map from basic block index to the leading label of that block. */
837 static tree *label_for_bb;
839 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
841 update_eh_label (struct eh_region *region)
843 tree old_label = get_eh_region_tree_label (region);
847 basic_block bb = label_to_block (old_label);
849 /* ??? After optimizing, there may be EH regions with labels
850 that have already been removed from the function body, so
851 there is no basic block for them. */
855 new_label = label_for_bb[bb->index];
856 set_eh_region_tree_label (region, new_label);
860 /* Given LABEL return the first label in the same basic block. */
862 main_block_label (tree label)
864 basic_block bb = label_to_block (label);
866 /* label_to_block possibly inserted undefined label into the chain. */
867 if (!label_for_bb[bb->index])
868 label_for_bb[bb->index] = label;
869 return label_for_bb[bb->index];
872 /* Cleanup redundant labels. This is a three-step process:
873 1) Find the leading label for each block.
874 2) Redirect all references to labels to the leading labels.
875 3) Cleanup all useless labels. */
878 cleanup_dead_labels (void)
881 label_for_bb = XCNEWVEC (tree, last_basic_block);
883 /* Find a suitable label for each block. We use the first user-defined
884 label if there is one, or otherwise just the first label we see. */
887 block_stmt_iterator i;
889 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
891 tree label, stmt = bsi_stmt (i);
893 if (TREE_CODE (stmt) != LABEL_EXPR)
896 label = LABEL_EXPR_LABEL (stmt);
898 /* If we have not yet seen a label for the current block,
899 remember this one and see if there are more labels. */
900 if (! label_for_bb[bb->index])
902 label_for_bb[bb->index] = label;
906 /* If we did see a label for the current block already, but it
907 is an artificially created label, replace it if the current
908 label is a user defined label. */
909 if (! DECL_ARTIFICIAL (label)
910 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
912 label_for_bb[bb->index] = label;
918 /* Now redirect all jumps/branches to the selected label.
919 First do so for each block ending in a control statement. */
922 tree stmt = last_stmt (bb);
926 switch (TREE_CODE (stmt))
930 tree true_branch, false_branch;
932 true_branch = COND_EXPR_THEN (stmt);
933 false_branch = COND_EXPR_ELSE (stmt);
936 GOTO_DESTINATION (true_branch)
937 = main_block_label (GOTO_DESTINATION (true_branch));
939 GOTO_DESTINATION (false_branch)
940 = main_block_label (GOTO_DESTINATION (false_branch));
948 tree vec = SWITCH_LABELS (stmt);
949 size_t n = TREE_VEC_LENGTH (vec);
951 /* Replace all destination labels. */
952 for (i = 0; i < n; ++i)
954 tree elt = TREE_VEC_ELT (vec, i);
955 tree label = main_block_label (CASE_LABEL (elt));
956 CASE_LABEL (elt) = label;
961 /* We have to handle GOTO_EXPRs until they're removed, and we don't
962 remove them until after we've created the CFG edges. */
964 if (! computed_goto_p (stmt))
966 GOTO_DESTINATION (stmt)
967 = main_block_label (GOTO_DESTINATION (stmt));
976 for_each_eh_region (update_eh_label);
978 /* Finally, purge dead labels. All user-defined labels and labels that
979 can be the target of non-local gotos and labels which have their
980 address taken are preserved. */
983 block_stmt_iterator i;
984 tree label_for_this_bb = label_for_bb[bb->index];
986 if (! label_for_this_bb)
989 for (i = bsi_start (bb); !bsi_end_p (i); )
991 tree label, stmt = bsi_stmt (i);
993 if (TREE_CODE (stmt) != LABEL_EXPR)
996 label = LABEL_EXPR_LABEL (stmt);
998 if (label == label_for_this_bb
999 || ! DECL_ARTIFICIAL (label)
1000 || DECL_NONLOCAL (label)
1001 || FORCED_LABEL (label))
1004 bsi_remove (&i, true);
1008 free (label_for_bb);
1011 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1012 and scan the sorted vector of cases. Combine the ones jumping to the
1014 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1017 group_case_labels (void)
1023 tree stmt = last_stmt (bb);
1024 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1026 tree labels = SWITCH_LABELS (stmt);
1027 int old_size = TREE_VEC_LENGTH (labels);
1028 int i, j, new_size = old_size;
1029 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1032 /* The default label is always the last case in a switch
1033 statement after gimplification. */
1034 default_label = CASE_LABEL (default_case);
1036 /* Look for possible opportunities to merge cases.
1037 Ignore the last element of the label vector because it
1038 must be the default case. */
1040 while (i < old_size - 1)
1042 tree base_case, base_label, base_high;
1043 base_case = TREE_VEC_ELT (labels, i);
1045 gcc_assert (base_case);
1046 base_label = CASE_LABEL (base_case);
1048 /* Discard cases that have the same destination as the
1050 if (base_label == default_label)
1052 TREE_VEC_ELT (labels, i) = NULL_TREE;
1058 base_high = CASE_HIGH (base_case) ?
1059 CASE_HIGH (base_case) : CASE_LOW (base_case);
1061 /* Try to merge case labels. Break out when we reach the end
1062 of the label vector or when we cannot merge the next case
1063 label with the current one. */
1064 while (i < old_size - 1)
1066 tree merge_case = TREE_VEC_ELT (labels, i);
1067 tree merge_label = CASE_LABEL (merge_case);
1068 tree t = int_const_binop (PLUS_EXPR, base_high,
1069 integer_one_node, 1);
1071 /* Merge the cases if they jump to the same place,
1072 and their ranges are consecutive. */
1073 if (merge_label == base_label
1074 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1076 base_high = CASE_HIGH (merge_case) ?
1077 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1078 CASE_HIGH (base_case) = base_high;
1079 TREE_VEC_ELT (labels, i) = NULL_TREE;
1088 /* Compress the case labels in the label vector, and adjust the
1089 length of the vector. */
1090 for (i = 0, j = 0; i < new_size; i++)
1092 while (! TREE_VEC_ELT (labels, j))
1094 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1096 TREE_VEC_LENGTH (labels) = new_size;
1101 /* Checks whether we can merge block B into block A. */
1104 tree_can_merge_blocks_p (basic_block a, basic_block b)
1107 block_stmt_iterator bsi;
1110 if (!single_succ_p (a))
1113 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1116 if (single_succ (a) != b)
1119 if (!single_pred_p (b))
1122 if (b == EXIT_BLOCK_PTR)
1125 /* If A ends by a statement causing exceptions or something similar, we
1126 cannot merge the blocks. */
1127 stmt = last_stmt (a);
1128 if (stmt && stmt_ends_bb_p (stmt))
1131 /* Do not allow a block with only a non-local label to be merged. */
1132 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1133 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1136 /* It must be possible to eliminate all phi nodes in B. If ssa form
1137 is not up-to-date, we cannot eliminate any phis; however, if only
1138 some symbols as whole are marked for renaming, this is not a problem,
1139 as phi nodes for those symbols are irrelevant in updating anyway. */
1140 phi = phi_nodes (b);
1143 if (name_mappings_registered_p ())
1146 for (; phi; phi = PHI_CHAIN (phi))
1147 if (!is_gimple_reg (PHI_RESULT (phi))
1148 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1152 /* Do not remove user labels. */
1153 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1155 stmt = bsi_stmt (bsi);
1156 if (TREE_CODE (stmt) != LABEL_EXPR)
1158 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1162 /* Protect the loop latches. */
1164 && b->loop_father->latch == b)
1170 /* Replaces all uses of NAME by VAL. */
1173 replace_uses_by (tree name, tree val)
1175 imm_use_iterator imm_iter;
1180 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1182 if (TREE_CODE (stmt) != PHI_NODE)
1183 push_stmt_changes (&stmt);
1185 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1187 replace_exp (use, val);
1189 if (TREE_CODE (stmt) == PHI_NODE)
1191 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1192 if (e->flags & EDGE_ABNORMAL)
1194 /* This can only occur for virtual operands, since
1195 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1196 would prevent replacement. */
1197 gcc_assert (!is_gimple_reg (name));
1198 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1203 if (TREE_CODE (stmt) != PHI_NODE)
1207 fold_stmt_inplace (stmt);
1208 if (cfgcleanup_altered_bbs)
1209 bitmap_set_bit (cfgcleanup_altered_bbs, bb_for_stmt (stmt)->index);
1211 /* FIXME. This should go in pop_stmt_changes. */
1212 rhs = get_rhs (stmt);
1213 if (TREE_CODE (rhs) == ADDR_EXPR)
1214 recompute_tree_invariant_for_addr_expr (rhs);
1216 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1218 pop_stmt_changes (&stmt);
1222 gcc_assert (has_zero_uses (name));
1224 /* Also update the trees stored in loop structures. */
1230 FOR_EACH_LOOP (li, loop, 0)
1232 substitute_in_loop_info (loop, name, val);
1237 /* Merge block B into block A. */
1240 tree_merge_blocks (basic_block a, basic_block b)
1242 block_stmt_iterator bsi;
1243 tree_stmt_iterator last;
1247 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1249 /* Remove all single-valued PHI nodes from block B of the form
1250 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1252 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1254 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1256 bool may_replace_uses = may_propagate_copy (def, use);
1258 /* In case we have loops to care about, do not propagate arguments of
1259 loop closed ssa phi nodes. */
1261 && is_gimple_reg (def)
1262 && TREE_CODE (use) == SSA_NAME
1263 && a->loop_father != b->loop_father)
1264 may_replace_uses = false;
1266 if (!may_replace_uses)
1268 gcc_assert (is_gimple_reg (def));
1270 /* Note that just emitting the copies is fine -- there is no problem
1271 with ordering of phi nodes. This is because A is the single
1272 predecessor of B, therefore results of the phi nodes cannot
1273 appear as arguments of the phi nodes. */
1274 copy = build_gimple_modify_stmt (def, use);
1275 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1276 SSA_NAME_DEF_STMT (def) = copy;
1277 remove_phi_node (phi, NULL, false);
1281 replace_uses_by (def, use);
1282 remove_phi_node (phi, NULL, true);
1286 /* Ensure that B follows A. */
1287 move_block_after (b, a);
1289 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1290 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1292 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1293 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1295 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1297 tree label = bsi_stmt (bsi);
1299 bsi_remove (&bsi, false);
1300 /* Now that we can thread computed gotos, we might have
1301 a situation where we have a forced label in block B
1302 However, the label at the start of block B might still be
1303 used in other ways (think about the runtime checking for
1304 Fortran assigned gotos). So we can not just delete the
1305 label. Instead we move the label to the start of block A. */
1306 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1308 block_stmt_iterator dest_bsi = bsi_start (a);
1309 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1314 change_bb_for_stmt (bsi_stmt (bsi), a);
1319 /* Merge the chains. */
1320 last = tsi_last (bb_stmt_list (a));
1321 tsi_link_after (&last, bb_stmt_list (b), TSI_NEW_STMT);
1322 set_bb_stmt_list (b, NULL_TREE);
1324 if (cfgcleanup_altered_bbs)
1325 bitmap_set_bit (cfgcleanup_altered_bbs, a->index);
1329 /* Return the one of two successors of BB that is not reachable by a
1330 reached by a complex edge, if there is one. Else, return BB. We use
1331 this in optimizations that use post-dominators for their heuristics,
1332 to catch the cases in C++ where function calls are involved. */
1335 single_noncomplex_succ (basic_block bb)
1338 if (EDGE_COUNT (bb->succs) != 2)
1341 e0 = EDGE_SUCC (bb, 0);
1342 e1 = EDGE_SUCC (bb, 1);
1343 if (e0->flags & EDGE_COMPLEX)
1345 if (e1->flags & EDGE_COMPLEX)
1352 /* Walk the function tree removing unnecessary statements.
1354 * Empty statement nodes are removed
1356 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1358 * Unnecessary COND_EXPRs are removed
1360 * Some unnecessary BIND_EXPRs are removed
1362 Clearly more work could be done. The trick is doing the analysis
1363 and removal fast enough to be a net improvement in compile times.
1365 Note that when we remove a control structure such as a COND_EXPR
1366 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1367 to ensure we eliminate all the useless code. */
1378 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1381 remove_useless_stmts_warn_notreached (tree stmt)
1383 if (EXPR_HAS_LOCATION (stmt))
1385 location_t loc = EXPR_LOCATION (stmt);
1386 if (LOCATION_LINE (loc) > 0)
1388 warning (0, "%Hwill never be executed", &loc);
1393 switch (TREE_CODE (stmt))
1395 case STATEMENT_LIST:
1397 tree_stmt_iterator i;
1398 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1399 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1405 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1407 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1409 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1413 case TRY_FINALLY_EXPR:
1414 case TRY_CATCH_EXPR:
1415 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1417 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1422 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1423 case EH_FILTER_EXPR:
1424 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1426 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1429 /* Not a live container. */
1437 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1439 tree then_clause, else_clause, cond;
1440 bool save_has_label, then_has_label, else_has_label;
1442 save_has_label = data->has_label;
1443 data->has_label = false;
1444 data->last_goto = NULL;
1446 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1448 then_has_label = data->has_label;
1449 data->has_label = false;
1450 data->last_goto = NULL;
1452 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1454 else_has_label = data->has_label;
1455 data->has_label = save_has_label | then_has_label | else_has_label;
1457 then_clause = COND_EXPR_THEN (*stmt_p);
1458 else_clause = COND_EXPR_ELSE (*stmt_p);
1459 cond = fold (COND_EXPR_COND (*stmt_p));
1461 /* If neither arm does anything at all, we can remove the whole IF. */
1462 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1464 *stmt_p = build_empty_stmt ();
1465 data->repeat = true;
1468 /* If there are no reachable statements in an arm, then we can
1469 zap the entire conditional. */
1470 else if (integer_nonzerop (cond) && !else_has_label)
1472 if (warn_notreached)
1473 remove_useless_stmts_warn_notreached (else_clause);
1474 *stmt_p = then_clause;
1475 data->repeat = true;
1477 else if (integer_zerop (cond) && !then_has_label)
1479 if (warn_notreached)
1480 remove_useless_stmts_warn_notreached (then_clause);
1481 *stmt_p = else_clause;
1482 data->repeat = true;
1485 /* Check a couple of simple things on then/else with single stmts. */
1488 tree then_stmt = expr_only (then_clause);
1489 tree else_stmt = expr_only (else_clause);
1491 /* Notice branches to a common destination. */
1492 if (then_stmt && else_stmt
1493 && TREE_CODE (then_stmt) == GOTO_EXPR
1494 && TREE_CODE (else_stmt) == GOTO_EXPR
1495 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1497 *stmt_p = then_stmt;
1498 data->repeat = true;
1501 /* If the THEN/ELSE clause merely assigns a value to a variable or
1502 parameter which is already known to contain that value, then
1503 remove the useless THEN/ELSE clause. */
1504 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1507 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1508 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1509 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1510 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1512 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1513 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1514 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1515 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1517 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1518 ? then_stmt : else_stmt);
1519 tree *location = (TREE_CODE (cond) == EQ_EXPR
1520 ? &COND_EXPR_THEN (*stmt_p)
1521 : &COND_EXPR_ELSE (*stmt_p));
1524 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1525 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1526 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1527 *location = alloc_stmt_list ();
1531 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1532 would be re-introduced during lowering. */
1533 data->last_goto = NULL;
1538 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1540 bool save_may_branch, save_may_throw;
1541 bool this_may_branch, this_may_throw;
1543 /* Collect may_branch and may_throw information for the body only. */
1544 save_may_branch = data->may_branch;
1545 save_may_throw = data->may_throw;
1546 data->may_branch = false;
1547 data->may_throw = false;
1548 data->last_goto = NULL;
1550 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1552 this_may_branch = data->may_branch;
1553 this_may_throw = data->may_throw;
1554 data->may_branch |= save_may_branch;
1555 data->may_throw |= save_may_throw;
1556 data->last_goto = NULL;
1558 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1560 /* If the body is empty, then we can emit the FINALLY block without
1561 the enclosing TRY_FINALLY_EXPR. */
1562 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1564 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1565 data->repeat = true;
1568 /* If the handler is empty, then we can emit the TRY block without
1569 the enclosing TRY_FINALLY_EXPR. */
1570 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1572 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1573 data->repeat = true;
1576 /* If the body neither throws, nor branches, then we can safely
1577 string the TRY and FINALLY blocks together. */
1578 else if (!this_may_branch && !this_may_throw)
1580 tree stmt = *stmt_p;
1581 *stmt_p = TREE_OPERAND (stmt, 0);
1582 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1583 data->repeat = true;
1589 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1591 bool save_may_throw, this_may_throw;
1592 tree_stmt_iterator i;
1595 /* Collect may_throw information for the body only. */
1596 save_may_throw = data->may_throw;
1597 data->may_throw = false;
1598 data->last_goto = NULL;
1600 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1602 this_may_throw = data->may_throw;
1603 data->may_throw = save_may_throw;
1605 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1606 if (!this_may_throw)
1608 if (warn_notreached)
1609 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1610 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1611 data->repeat = true;
1615 /* Process the catch clause specially. We may be able to tell that
1616 no exceptions propagate past this point. */
1618 this_may_throw = true;
1619 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1620 stmt = tsi_stmt (i);
1621 data->last_goto = NULL;
1623 switch (TREE_CODE (stmt))
1626 for (; !tsi_end_p (i); tsi_next (&i))
1628 stmt = tsi_stmt (i);
1629 /* If we catch all exceptions, then the body does not
1630 propagate exceptions past this point. */
1631 if (CATCH_TYPES (stmt) == NULL)
1632 this_may_throw = false;
1633 data->last_goto = NULL;
1634 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1638 case EH_FILTER_EXPR:
1639 if (EH_FILTER_MUST_NOT_THROW (stmt))
1640 this_may_throw = false;
1641 else if (EH_FILTER_TYPES (stmt) == NULL)
1642 this_may_throw = false;
1643 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1647 /* Otherwise this is a cleanup. */
1648 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1650 /* If the cleanup is empty, then we can emit the TRY block without
1651 the enclosing TRY_CATCH_EXPR. */
1652 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1654 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1655 data->repeat = true;
1659 data->may_throw |= this_may_throw;
1664 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1668 /* First remove anything underneath the BIND_EXPR. */
1669 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1671 /* If the BIND_EXPR has no variables, then we can pull everything
1672 up one level and remove the BIND_EXPR, unless this is the toplevel
1673 BIND_EXPR for the current function or an inlined function.
1675 When this situation occurs we will want to apply this
1676 optimization again. */
1677 block = BIND_EXPR_BLOCK (*stmt_p);
1678 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1679 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1681 || ! BLOCK_ABSTRACT_ORIGIN (block)
1682 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1685 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1686 data->repeat = true;
1692 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1694 tree dest = GOTO_DESTINATION (*stmt_p);
1696 data->may_branch = true;
1697 data->last_goto = NULL;
1699 /* Record the last goto expr, so that we can delete it if unnecessary. */
1700 if (TREE_CODE (dest) == LABEL_DECL)
1701 data->last_goto = stmt_p;
1706 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1708 tree label = LABEL_EXPR_LABEL (*stmt_p);
1710 data->has_label = true;
1712 /* We do want to jump across non-local label receiver code. */
1713 if (DECL_NONLOCAL (label))
1714 data->last_goto = NULL;
1716 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1718 *data->last_goto = build_empty_stmt ();
1719 data->repeat = true;
1722 /* ??? Add something here to delete unused labels. */
1726 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1727 decl. This allows us to eliminate redundant or useless
1728 calls to "const" functions.
1730 Gimplifier already does the same operation, but we may notice functions
1731 being const and pure once their calls has been gimplified, so we need
1732 to update the flag. */
1735 update_call_expr_flags (tree call)
1737 tree decl = get_callee_fndecl (call);
1740 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1741 TREE_SIDE_EFFECTS (call) = 0;
1742 if (TREE_NOTHROW (decl))
1743 TREE_NOTHROW (call) = 1;
1747 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1750 notice_special_calls (tree t)
1752 int flags = call_expr_flags (t);
1754 if (flags & ECF_MAY_BE_ALLOCA)
1755 current_function_calls_alloca = true;
1756 if (flags & ECF_RETURNS_TWICE)
1757 current_function_calls_setjmp = true;
1761 /* Clear flags set by notice_special_calls. Used by dead code removal
1762 to update the flags. */
1765 clear_special_calls (void)
1767 current_function_calls_alloca = false;
1768 current_function_calls_setjmp = false;
1773 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1777 switch (TREE_CODE (t))
1780 remove_useless_stmts_cond (tp, data);
1783 case TRY_FINALLY_EXPR:
1784 remove_useless_stmts_tf (tp, data);
1787 case TRY_CATCH_EXPR:
1788 remove_useless_stmts_tc (tp, data);
1792 remove_useless_stmts_bind (tp, data);
1796 remove_useless_stmts_goto (tp, data);
1800 remove_useless_stmts_label (tp, data);
1805 data->last_goto = NULL;
1806 data->may_branch = true;
1811 data->last_goto = NULL;
1812 notice_special_calls (t);
1813 update_call_expr_flags (t);
1814 if (tree_could_throw_p (t))
1815 data->may_throw = true;
1821 case GIMPLE_MODIFY_STMT:
1822 data->last_goto = NULL;
1824 op = get_call_expr_in (t);
1827 update_call_expr_flags (op);
1828 notice_special_calls (op);
1830 if (tree_could_throw_p (t))
1831 data->may_throw = true;
1834 case STATEMENT_LIST:
1836 tree_stmt_iterator i = tsi_start (t);
1837 while (!tsi_end_p (i))
1840 if (IS_EMPTY_STMT (t))
1846 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1849 if (TREE_CODE (t) == STATEMENT_LIST)
1851 tsi_link_before (&i, t, TSI_SAME_STMT);
1861 data->last_goto = NULL;
1865 data->last_goto = NULL;
1871 remove_useless_stmts (void)
1873 struct rus_data data;
1875 clear_special_calls ();
1879 memset (&data, 0, sizeof (data));
1880 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1882 while (data.repeat);
1887 struct tree_opt_pass pass_remove_useless_stmts =
1889 "useless", /* name */
1891 remove_useless_stmts, /* execute */
1894 0, /* static_pass_number */
1896 PROP_gimple_any, /* properties_required */
1897 0, /* properties_provided */
1898 0, /* properties_destroyed */
1899 0, /* todo_flags_start */
1900 TODO_dump_func, /* todo_flags_finish */
1904 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1907 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1911 /* Since this block is no longer reachable, we can just delete all
1912 of its PHI nodes. */
1913 phi = phi_nodes (bb);
1916 tree next = PHI_CHAIN (phi);
1917 remove_phi_node (phi, NULL_TREE, true);
1921 /* Remove edges to BB's successors. */
1922 while (EDGE_COUNT (bb->succs) > 0)
1923 remove_edge (EDGE_SUCC (bb, 0));
1927 /* Remove statements of basic block BB. */
1930 remove_bb (basic_block bb)
1932 block_stmt_iterator i;
1933 #ifdef USE_MAPPED_LOCATION
1934 source_location loc = UNKNOWN_LOCATION;
1936 source_locus loc = 0;
1941 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1942 if (dump_flags & TDF_DETAILS)
1944 dump_bb (bb, dump_file, 0);
1945 fprintf (dump_file, "\n");
1951 struct loop *loop = bb->loop_father;
1953 /* If a loop gets removed, clean up the information associated
1955 if (loop->latch == bb
1956 || loop->header == bb)
1957 free_numbers_of_iterations_estimates_loop (loop);
1960 /* Remove all the instructions in the block. */
1961 if (bb_stmt_list (bb) != NULL_TREE)
1963 for (i = bsi_start (bb); !bsi_end_p (i);)
1965 tree stmt = bsi_stmt (i);
1966 if (TREE_CODE (stmt) == LABEL_EXPR
1967 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
1968 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
1971 block_stmt_iterator new_bsi;
1973 /* A non-reachable non-local label may still be referenced.
1974 But it no longer needs to carry the extra semantics of
1976 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1978 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
1979 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
1982 new_bb = bb->prev_bb;
1983 new_bsi = bsi_start (new_bb);
1984 bsi_remove (&i, false);
1985 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
1989 /* Release SSA definitions if we are in SSA. Note that we
1990 may be called when not in SSA. For example,
1991 final_cleanup calls this function via
1992 cleanup_tree_cfg. */
1993 if (gimple_in_ssa_p (cfun))
1994 release_defs (stmt);
1996 bsi_remove (&i, true);
1999 /* Don't warn for removed gotos. Gotos are often removed due to
2000 jump threading, thus resulting in bogus warnings. Not great,
2001 since this way we lose warnings for gotos in the original
2002 program that are indeed unreachable. */
2003 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2005 #ifdef USE_MAPPED_LOCATION
2006 if (EXPR_HAS_LOCATION (stmt))
2007 loc = EXPR_LOCATION (stmt);
2010 t = EXPR_LOCUS (stmt);
2011 if (t && LOCATION_LINE (*t) > 0)
2018 /* If requested, give a warning that the first statement in the
2019 block is unreachable. We walk statements backwards in the
2020 loop above, so the last statement we process is the first statement
2022 #ifdef USE_MAPPED_LOCATION
2023 if (loc > BUILTINS_LOCATION)
2024 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2027 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2030 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2035 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2036 predicate VAL, return the edge that will be taken out of the block.
2037 If VAL does not match a unique edge, NULL is returned. */
2040 find_taken_edge (basic_block bb, tree val)
2044 stmt = last_stmt (bb);
2047 gcc_assert (is_ctrl_stmt (stmt));
2050 if (! is_gimple_min_invariant (val))
2053 if (TREE_CODE (stmt) == COND_EXPR)
2054 return find_taken_edge_cond_expr (bb, val);
2056 if (TREE_CODE (stmt) == SWITCH_EXPR)
2057 return find_taken_edge_switch_expr (bb, val);
2059 if (computed_goto_p (stmt))
2061 /* Only optimize if the argument is a label, if the argument is
2062 not a label then we can not construct a proper CFG.
2064 It may be the case that we only need to allow the LABEL_REF to
2065 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2066 appear inside a LABEL_EXPR just to be safe. */
2067 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2068 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2069 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2076 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2077 statement, determine which of the outgoing edges will be taken out of the
2078 block. Return NULL if either edge may be taken. */
2081 find_taken_edge_computed_goto (basic_block bb, tree val)
2086 dest = label_to_block (val);
2089 e = find_edge (bb, dest);
2090 gcc_assert (e != NULL);
2096 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2097 statement, determine which of the two edges will be taken out of the
2098 block. Return NULL if either edge may be taken. */
2101 find_taken_edge_cond_expr (basic_block bb, tree val)
2103 edge true_edge, false_edge;
2105 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2107 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2108 return (integer_zerop (val) ? false_edge : true_edge);
2111 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2112 statement, determine which edge will be taken out of the block. Return
2113 NULL if any edge may be taken. */
2116 find_taken_edge_switch_expr (basic_block bb, tree val)
2118 tree switch_expr, taken_case;
2119 basic_block dest_bb;
2122 switch_expr = last_stmt (bb);
2123 taken_case = find_case_label_for_value (switch_expr, val);
2124 dest_bb = label_to_block (CASE_LABEL (taken_case));
2126 e = find_edge (bb, dest_bb);
2132 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2133 We can make optimal use here of the fact that the case labels are
2134 sorted: We can do a binary search for a case matching VAL. */
2137 find_case_label_for_value (tree switch_expr, tree val)
2139 tree vec = SWITCH_LABELS (switch_expr);
2140 size_t low, high, n = TREE_VEC_LENGTH (vec);
2141 tree default_case = TREE_VEC_ELT (vec, n - 1);
2143 for (low = -1, high = n - 1; high - low > 1; )
2145 size_t i = (high + low) / 2;
2146 tree t = TREE_VEC_ELT (vec, i);
2149 /* Cache the result of comparing CASE_LOW and val. */
2150 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2157 if (CASE_HIGH (t) == NULL)
2159 /* A singe-valued case label. */
2165 /* A case range. We can only handle integer ranges. */
2166 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2171 return default_case;
2177 /*---------------------------------------------------------------------------
2179 ---------------------------------------------------------------------------*/
2181 /* Dump tree-specific information of block BB to file OUTF. */
2184 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2186 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2190 /* Dump a basic block on stderr. */
2193 debug_tree_bb (basic_block bb)
2195 dump_bb (bb, stderr, 0);
2199 /* Dump basic block with index N on stderr. */
2202 debug_tree_bb_n (int n)
2204 debug_tree_bb (BASIC_BLOCK (n));
2205 return BASIC_BLOCK (n);
2209 /* Dump the CFG on stderr.
2211 FLAGS are the same used by the tree dumping functions
2212 (see TDF_* in tree-pass.h). */
2215 debug_tree_cfg (int flags)
2217 dump_tree_cfg (stderr, flags);
2221 /* Dump the program showing basic block boundaries on the given FILE.
2223 FLAGS are the same used by the tree dumping functions (see TDF_* in
2227 dump_tree_cfg (FILE *file, int flags)
2229 if (flags & TDF_DETAILS)
2231 const char *funcname
2232 = lang_hooks.decl_printable_name (current_function_decl, 2);
2235 fprintf (file, ";; Function %s\n\n", funcname);
2236 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2237 n_basic_blocks, n_edges, last_basic_block);
2239 brief_dump_cfg (file);
2240 fprintf (file, "\n");
2243 if (flags & TDF_STATS)
2244 dump_cfg_stats (file);
2246 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2250 /* Dump CFG statistics on FILE. */
2253 dump_cfg_stats (FILE *file)
2255 static long max_num_merged_labels = 0;
2256 unsigned long size, total = 0;
2259 const char * const fmt_str = "%-30s%-13s%12s\n";
2260 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2261 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2262 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2263 const char *funcname
2264 = lang_hooks.decl_printable_name (current_function_decl, 2);
2267 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2269 fprintf (file, "---------------------------------------------------------\n");
2270 fprintf (file, fmt_str, "", " Number of ", "Memory");
2271 fprintf (file, fmt_str, "", " instances ", "used ");
2272 fprintf (file, "---------------------------------------------------------\n");
2274 size = n_basic_blocks * sizeof (struct basic_block_def);
2276 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2277 SCALE (size), LABEL (size));
2281 num_edges += EDGE_COUNT (bb->succs);
2282 size = num_edges * sizeof (struct edge_def);
2284 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2286 fprintf (file, "---------------------------------------------------------\n");
2287 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2289 fprintf (file, "---------------------------------------------------------\n");
2290 fprintf (file, "\n");
2292 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2293 max_num_merged_labels = cfg_stats.num_merged_labels;
2295 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2296 cfg_stats.num_merged_labels, max_num_merged_labels);
2298 fprintf (file, "\n");
2302 /* Dump CFG statistics on stderr. Keep extern so that it's always
2303 linked in the final executable. */
2306 debug_cfg_stats (void)
2308 dump_cfg_stats (stderr);
2312 /* Dump the flowgraph to a .vcg FILE. */
2315 tree_cfg2vcg (FILE *file)
2320 const char *funcname
2321 = lang_hooks.decl_printable_name (current_function_decl, 2);
2323 /* Write the file header. */
2324 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2325 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2326 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2328 /* Write blocks and edges. */
2329 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2331 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2334 if (e->flags & EDGE_FAKE)
2335 fprintf (file, " linestyle: dotted priority: 10");
2337 fprintf (file, " linestyle: solid priority: 100");
2339 fprintf (file, " }\n");
2345 enum tree_code head_code, end_code;
2346 const char *head_name, *end_name;
2349 tree first = first_stmt (bb);
2350 tree last = last_stmt (bb);
2354 head_code = TREE_CODE (first);
2355 head_name = tree_code_name[head_code];
2356 head_line = get_lineno (first);
2359 head_name = "no-statement";
2363 end_code = TREE_CODE (last);
2364 end_name = tree_code_name[end_code];
2365 end_line = get_lineno (last);
2368 end_name = "no-statement";
2370 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2371 bb->index, bb->index, head_name, head_line, end_name,
2374 FOR_EACH_EDGE (e, ei, bb->succs)
2376 if (e->dest == EXIT_BLOCK_PTR)
2377 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2379 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2381 if (e->flags & EDGE_FAKE)
2382 fprintf (file, " priority: 10 linestyle: dotted");
2384 fprintf (file, " priority: 100 linestyle: solid");
2386 fprintf (file, " }\n");
2389 if (bb->next_bb != EXIT_BLOCK_PTR)
2393 fputs ("}\n\n", file);
2398 /*---------------------------------------------------------------------------
2399 Miscellaneous helpers
2400 ---------------------------------------------------------------------------*/
2402 /* Return true if T represents a stmt that always transfers control. */
2405 is_ctrl_stmt (tree t)
2407 return (TREE_CODE (t) == COND_EXPR
2408 || TREE_CODE (t) == SWITCH_EXPR
2409 || TREE_CODE (t) == GOTO_EXPR
2410 || TREE_CODE (t) == RETURN_EXPR
2411 || TREE_CODE (t) == RESX_EXPR);
2415 /* Return true if T is a statement that may alter the flow of control
2416 (e.g., a call to a non-returning function). */
2419 is_ctrl_altering_stmt (tree t)
2424 call = get_call_expr_in (t);
2427 /* A non-pure/const CALL_EXPR alters flow control if the current
2428 function has nonlocal labels. */
2429 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2432 /* A CALL_EXPR also alters control flow if it does not return. */
2433 if (call_expr_flags (call) & ECF_NORETURN)
2437 /* OpenMP directives alter control flow. */
2438 if (OMP_DIRECTIVE_P (t))
2441 /* If a statement can throw, it alters control flow. */
2442 return tree_can_throw_internal (t);
2446 /* Return true if T is a computed goto. */
2449 computed_goto_p (tree t)
2451 return (TREE_CODE (t) == GOTO_EXPR
2452 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2456 /* Return true if T is a simple local goto. */
2459 simple_goto_p (tree t)
2461 return (TREE_CODE (t) == GOTO_EXPR
2462 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2466 /* Return true if T can make an abnormal transfer of control flow.
2467 Transfers of control flow associated with EH are excluded. */
2470 tree_can_make_abnormal_goto (tree t)
2472 if (computed_goto_p (t))
2474 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2475 t = GIMPLE_STMT_OPERAND (t, 1);
2476 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2477 t = TREE_OPERAND (t, 0);
2478 if (TREE_CODE (t) == CALL_EXPR)
2479 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2484 /* Return true if T should start a new basic block. PREV_T is the
2485 statement preceding T. It is used when T is a label or a case label.
2486 Labels should only start a new basic block if their previous statement
2487 wasn't a label. Otherwise, sequence of labels would generate
2488 unnecessary basic blocks that only contain a single label. */
2491 stmt_starts_bb_p (tree t, tree prev_t)
2496 /* LABEL_EXPRs start a new basic block only if the preceding
2497 statement wasn't a label of the same type. This prevents the
2498 creation of consecutive blocks that have nothing but a single
2500 if (TREE_CODE (t) == LABEL_EXPR)
2502 /* Nonlocal and computed GOTO targets always start a new block. */
2503 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2504 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2507 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2509 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2512 cfg_stats.num_merged_labels++;
2523 /* Return true if T should end a basic block. */
2526 stmt_ends_bb_p (tree t)
2528 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2531 /* Remove block annotations and other datastructures. */
2534 delete_tree_cfg_annotations (void)
2537 block_stmt_iterator bsi;
2539 /* Remove annotations from every tree in the function. */
2541 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2543 tree stmt = bsi_stmt (bsi);
2544 ggc_free (stmt->base.ann);
2545 stmt->base.ann = NULL;
2547 label_to_block_map = NULL;
2551 /* Return the first statement in basic block BB. */
2554 first_stmt (basic_block bb)
2556 block_stmt_iterator i = bsi_start (bb);
2557 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2561 /* Return the last statement in basic block BB. */
2564 last_stmt (basic_block bb)
2566 block_stmt_iterator b = bsi_last (bb);
2567 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2571 /* Return the last statement of an otherwise empty block. Return NULL
2572 if the block is totally empty, or if it contains more than one
2576 last_and_only_stmt (basic_block bb)
2578 block_stmt_iterator i = bsi_last (bb);
2584 last = bsi_stmt (i);
2589 /* Empty statements should no longer appear in the instruction stream.
2590 Everything that might have appeared before should be deleted by
2591 remove_useless_stmts, and the optimizers should just bsi_remove
2592 instead of smashing with build_empty_stmt.
2594 Thus the only thing that should appear here in a block containing
2595 one executable statement is a label. */
2596 prev = bsi_stmt (i);
2597 if (TREE_CODE (prev) == LABEL_EXPR)
2604 /* Mark BB as the basic block holding statement T. */
2607 set_bb_for_stmt (tree t, basic_block bb)
2609 if (TREE_CODE (t) == PHI_NODE)
2611 else if (TREE_CODE (t) == STATEMENT_LIST)
2613 tree_stmt_iterator i;
2614 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2615 set_bb_for_stmt (tsi_stmt (i), bb);
2619 stmt_ann_t ann = get_stmt_ann (t);
2622 /* If the statement is a label, add the label to block-to-labels map
2623 so that we can speed up edge creation for GOTO_EXPRs. */
2624 if (TREE_CODE (t) == LABEL_EXPR)
2628 t = LABEL_EXPR_LABEL (t);
2629 uid = LABEL_DECL_UID (t);
2632 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2633 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2634 if (old_len <= (unsigned) uid)
2636 unsigned new_len = 3 * uid / 2;
2638 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2643 /* We're moving an existing label. Make sure that we've
2644 removed it from the old block. */
2646 || !VEC_index (basic_block, label_to_block_map, uid));
2647 VEC_replace (basic_block, label_to_block_map, uid, bb);
2652 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2653 from one basic block to another.
2654 For BB splitting we can run into quadratic case, so performance is quite
2655 important and knowing that the tables are big enough, change_bb_for_stmt
2656 can inline as leaf function. */
2658 change_bb_for_stmt (tree t, basic_block bb)
2660 get_stmt_ann (t)->bb = bb;
2661 if (TREE_CODE (t) == LABEL_EXPR)
2662 VEC_replace (basic_block, label_to_block_map,
2663 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2666 /* Finds iterator for STMT. */
2668 extern block_stmt_iterator
2669 bsi_for_stmt (tree stmt)
2671 block_stmt_iterator bsi;
2673 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2674 if (bsi_stmt (bsi) == stmt)
2680 /* Mark statement T as modified, and update it. */
2682 update_modified_stmts (tree t)
2684 if (!ssa_operands_active ())
2686 if (TREE_CODE (t) == STATEMENT_LIST)
2688 tree_stmt_iterator i;
2690 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2692 stmt = tsi_stmt (i);
2693 update_stmt_if_modified (stmt);
2697 update_stmt_if_modified (t);
2700 /* Insert statement (or statement list) T before the statement
2701 pointed-to by iterator I. M specifies how to update iterator I
2702 after insertion (see enum bsi_iterator_update). */
2705 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2707 set_bb_for_stmt (t, i->bb);
2708 update_modified_stmts (t);
2709 tsi_link_before (&i->tsi, t, m);
2713 /* Insert statement (or statement list) T after the statement
2714 pointed-to by iterator I. M specifies how to update iterator I
2715 after insertion (see enum bsi_iterator_update). */
2718 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2720 set_bb_for_stmt (t, i->bb);
2721 update_modified_stmts (t);
2722 tsi_link_after (&i->tsi, t, m);
2726 /* Remove the statement pointed to by iterator I. The iterator is updated
2727 to the next statement.
2729 When REMOVE_EH_INFO is true we remove the statement pointed to by
2730 iterator I from the EH tables. Otherwise we do not modify the EH
2733 Generally, REMOVE_EH_INFO should be true when the statement is going to
2734 be removed from the IL and not reinserted elsewhere. */
2737 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2739 tree t = bsi_stmt (*i);
2740 set_bb_for_stmt (t, NULL);
2741 delink_stmt_imm_use (t);
2742 tsi_delink (&i->tsi);
2743 mark_stmt_modified (t);
2746 remove_stmt_from_eh_region (t);
2747 gimple_remove_stmt_histograms (cfun, t);
2752 /* Move the statement at FROM so it comes right after the statement at TO. */
2755 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2757 tree stmt = bsi_stmt (*from);
2758 bsi_remove (from, false);
2759 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2763 /* Move the statement at FROM so it comes right before the statement at TO. */
2766 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2768 tree stmt = bsi_stmt (*from);
2769 bsi_remove (from, false);
2770 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2774 /* Move the statement at FROM to the end of basic block BB. */
2777 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2779 block_stmt_iterator last = bsi_last (bb);
2781 /* Have to check bsi_end_p because it could be an empty block. */
2782 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2783 bsi_move_before (from, &last);
2785 bsi_move_after (from, &last);
2789 /* Replace the contents of the statement pointed to by iterator BSI
2790 with STMT. If UPDATE_EH_INFO is true, the exception handling
2791 information of the original statement is moved to the new statement. */
2794 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2797 tree orig_stmt = bsi_stmt (*bsi);
2799 if (stmt == orig_stmt)
2801 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2802 set_bb_for_stmt (stmt, bsi->bb);
2804 /* Preserve EH region information from the original statement, if
2805 requested by the caller. */
2808 eh_region = lookup_stmt_eh_region (orig_stmt);
2811 remove_stmt_from_eh_region (orig_stmt);
2812 add_stmt_to_eh_region (stmt, eh_region);
2816 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2817 gimple_remove_stmt_histograms (cfun, orig_stmt);
2818 delink_stmt_imm_use (orig_stmt);
2819 *bsi_stmt_ptr (*bsi) = stmt;
2820 mark_stmt_modified (stmt);
2821 update_modified_stmts (stmt);
2825 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2826 is made to place the statement in an existing basic block, but
2827 sometimes that isn't possible. When it isn't possible, the edge is
2828 split and the statement is added to the new block.
2830 In all cases, the returned *BSI points to the correct location. The
2831 return value is true if insertion should be done after the location,
2832 or false if it should be done before the location. If new basic block
2833 has to be created, it is stored in *NEW_BB. */
2836 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2837 basic_block *new_bb)
2839 basic_block dest, src;
2845 /* If the destination has one predecessor which has no PHI nodes,
2846 insert there. Except for the exit block.
2848 The requirement for no PHI nodes could be relaxed. Basically we
2849 would have to examine the PHIs to prove that none of them used
2850 the value set by the statement we want to insert on E. That
2851 hardly seems worth the effort. */
2852 if (single_pred_p (dest)
2853 && ! phi_nodes (dest)
2854 && dest != EXIT_BLOCK_PTR)
2856 *bsi = bsi_start (dest);
2857 if (bsi_end_p (*bsi))
2860 /* Make sure we insert after any leading labels. */
2861 tmp = bsi_stmt (*bsi);
2862 while (TREE_CODE (tmp) == LABEL_EXPR)
2865 if (bsi_end_p (*bsi))
2867 tmp = bsi_stmt (*bsi);
2870 if (bsi_end_p (*bsi))
2872 *bsi = bsi_last (dest);
2879 /* If the source has one successor, the edge is not abnormal and
2880 the last statement does not end a basic block, insert there.
2881 Except for the entry block. */
2883 if ((e->flags & EDGE_ABNORMAL) == 0
2884 && single_succ_p (src)
2885 && src != ENTRY_BLOCK_PTR)
2887 *bsi = bsi_last (src);
2888 if (bsi_end_p (*bsi))
2891 tmp = bsi_stmt (*bsi);
2892 if (!stmt_ends_bb_p (tmp))
2895 /* Insert code just before returning the value. We may need to decompose
2896 the return in the case it contains non-trivial operand. */
2897 if (TREE_CODE (tmp) == RETURN_EXPR)
2899 tree op = TREE_OPERAND (tmp, 0);
2900 if (op && !is_gimple_val (op))
2902 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
2903 bsi_insert_before (bsi, op, BSI_NEW_STMT);
2904 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
2911 /* Otherwise, create a new basic block, and split this edge. */
2912 dest = split_edge (e);
2915 e = single_pred_edge (dest);
2920 /* This routine will commit all pending edge insertions, creating any new
2921 basic blocks which are necessary. */
2924 bsi_commit_edge_inserts (void)
2930 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
2933 FOR_EACH_EDGE (e, ei, bb->succs)
2934 bsi_commit_one_edge_insert (e, NULL);
2938 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2939 to this block, otherwise set it to NULL. */
2942 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
2946 if (PENDING_STMT (e))
2948 block_stmt_iterator bsi;
2949 tree stmt = PENDING_STMT (e);
2951 PENDING_STMT (e) = NULL_TREE;
2953 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
2954 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
2956 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
2961 /* Add STMT to the pending list of edge E. No actual insertion is
2962 made until a call to bsi_commit_edge_inserts () is made. */
2965 bsi_insert_on_edge (edge e, tree stmt)
2967 append_to_statement_list (stmt, &PENDING_STMT (e));
2970 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
2971 block has to be created, it is returned. */
2974 bsi_insert_on_edge_immediate (edge e, tree stmt)
2976 block_stmt_iterator bsi;
2977 basic_block new_bb = NULL;
2979 gcc_assert (!PENDING_STMT (e));
2981 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
2982 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
2984 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
2989 /*---------------------------------------------------------------------------
2990 Tree specific functions for CFG manipulation
2991 ---------------------------------------------------------------------------*/
2993 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
2996 reinstall_phi_args (edge new_edge, edge old_edge)
3000 if (!PENDING_STMT (old_edge))
3003 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3005 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3007 tree result = TREE_PURPOSE (var);
3008 tree arg = TREE_VALUE (var);
3010 gcc_assert (result == PHI_RESULT (phi));
3012 add_phi_arg (phi, arg, new_edge);
3015 PENDING_STMT (old_edge) = NULL;
3018 /* Returns the basic block after which the new basic block created
3019 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3020 near its "logical" location. This is of most help to humans looking
3021 at debugging dumps. */
3024 split_edge_bb_loc (edge edge_in)
3026 basic_block dest = edge_in->dest;
3028 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3029 return edge_in->src;
3031 return dest->prev_bb;
3034 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3035 Abort on abnormal edges. */
3038 tree_split_edge (edge edge_in)
3040 basic_block new_bb, after_bb, dest;
3043 /* Abnormal edges cannot be split. */
3044 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3046 dest = edge_in->dest;
3048 after_bb = split_edge_bb_loc (edge_in);
3050 new_bb = create_empty_bb (after_bb);
3051 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3052 new_bb->count = edge_in->count;
3053 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3054 new_edge->probability = REG_BR_PROB_BASE;
3055 new_edge->count = edge_in->count;
3057 e = redirect_edge_and_branch (edge_in, new_bb);
3058 gcc_assert (e == edge_in);
3059 reinstall_phi_args (new_edge, e);
3064 /* Callback for walk_tree, check that all elements with address taken are
3065 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3066 inside a PHI node. */
3069 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3072 bool in_phi = (data != NULL);
3077 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3078 #define CHECK_OP(N, MSG) \
3079 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3080 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3082 switch (TREE_CODE (t))
3085 if (SSA_NAME_IN_FREE_LIST (t))
3087 error ("SSA name in freelist but still referenced");
3093 x = fold (ASSERT_EXPR_COND (t));
3094 if (x == boolean_false_node)
3096 error ("ASSERT_EXPR with an always-false condition");
3104 case GIMPLE_MODIFY_STMT:
3105 x = GIMPLE_STMT_OPERAND (t, 0);
3106 if (TREE_CODE (x) == BIT_FIELD_REF
3107 && is_gimple_reg (TREE_OPERAND (x, 0)))
3109 error ("GIMPLE register modified with BIT_FIELD_REF");
3118 bool old_side_effects;
3121 bool new_side_effects;
3123 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3124 dead PHIs that take the address of something. But if the PHI
3125 result is dead, the fact that it takes the address of anything
3126 is irrelevant. Because we can not tell from here if a PHI result
3127 is dead, we just skip this check for PHIs altogether. This means
3128 we may be missing "valid" checks, but what can you do?
3129 This was PR19217. */
3133 old_invariant = TREE_INVARIANT (t);
3134 old_constant = TREE_CONSTANT (t);
3135 old_side_effects = TREE_SIDE_EFFECTS (t);
3137 recompute_tree_invariant_for_addr_expr (t);
3138 new_invariant = TREE_INVARIANT (t);
3139 new_side_effects = TREE_SIDE_EFFECTS (t);
3140 new_constant = TREE_CONSTANT (t);
3142 if (old_invariant != new_invariant)
3144 error ("invariant not recomputed when ADDR_EXPR changed");
3148 if (old_constant != new_constant)
3150 error ("constant not recomputed when ADDR_EXPR changed");
3153 if (old_side_effects != new_side_effects)
3155 error ("side effects not recomputed when ADDR_EXPR changed");
3159 /* Skip any references (they will be checked when we recurse down the
3160 tree) and ensure that any variable used as a prefix is marked
3162 for (x = TREE_OPERAND (t, 0);
3163 handled_component_p (x);
3164 x = TREE_OPERAND (x, 0))
3167 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3169 if (!TREE_ADDRESSABLE (x))
3171 error ("address taken, but ADDRESSABLE bit not set");
3178 x = COND_EXPR_COND (t);
3179 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3181 error ("non-boolean used in condition");
3184 if (!is_gimple_condexpr (x))
3186 error ("invalid conditional operand");
3193 case FIX_TRUNC_EXPR:
3198 case NON_LVALUE_EXPR:
3199 case TRUTH_NOT_EXPR:
3200 CHECK_OP (0, "invalid operand to unary operator");
3207 case ARRAY_RANGE_REF:
3209 case VIEW_CONVERT_EXPR:
3210 /* We have a nest of references. Verify that each of the operands
3211 that determine where to reference is either a constant or a variable,
3212 verify that the base is valid, and then show we've already checked
3214 while (handled_component_p (t))
3216 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3217 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3218 else if (TREE_CODE (t) == ARRAY_REF
3219 || TREE_CODE (t) == ARRAY_RANGE_REF)
3221 CHECK_OP (1, "invalid array index");
3222 if (TREE_OPERAND (t, 2))
3223 CHECK_OP (2, "invalid array lower bound");
3224 if (TREE_OPERAND (t, 3))
3225 CHECK_OP (3, "invalid array stride");
3227 else if (TREE_CODE (t) == BIT_FIELD_REF)
3229 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3230 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3233 t = TREE_OPERAND (t, 0);
3236 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3238 error ("invalid reference prefix");
3250 case UNORDERED_EXPR:
3261 case TRUNC_DIV_EXPR:
3263 case FLOOR_DIV_EXPR:
3264 case ROUND_DIV_EXPR:
3265 case TRUNC_MOD_EXPR:
3267 case FLOOR_MOD_EXPR:
3268 case ROUND_MOD_EXPR:
3270 case EXACT_DIV_EXPR:
3280 CHECK_OP (0, "invalid operand to binary operator");
3281 CHECK_OP (1, "invalid operand to binary operator");
3285 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3298 /* Verify STMT, return true if STMT is not in GIMPLE form.
3299 TODO: Implement type checking. */
3302 verify_stmt (tree stmt, bool last_in_block)
3306 if (OMP_DIRECTIVE_P (stmt))
3308 /* OpenMP directives are validated by the FE and never operated
3309 on by the optimizers. Furthermore, OMP_FOR may contain
3310 non-gimple expressions when the main index variable has had
3311 its address taken. This does not affect the loop itself
3312 because the header of an OMP_FOR is merely used to determine
3313 how to setup the parallel iteration. */
3317 if (!is_gimple_stmt (stmt))
3319 error ("is not a valid GIMPLE statement");
3323 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3326 debug_generic_stmt (addr);
3330 /* If the statement is marked as part of an EH region, then it is
3331 expected that the statement could throw. Verify that when we
3332 have optimizations that simplify statements such that we prove
3333 that they cannot throw, that we update other data structures
3335 if (lookup_stmt_eh_region (stmt) >= 0)
3337 if (!tree_could_throw_p (stmt))
3339 error ("statement marked for throw, but doesn%'t");
3342 if (!last_in_block && tree_can_throw_internal (stmt))
3344 error ("statement marked for throw in middle of block");
3352 debug_generic_stmt (stmt);
3357 /* Return true when the T can be shared. */
3360 tree_node_can_be_shared (tree t)
3362 if (IS_TYPE_OR_DECL_P (t)
3363 || is_gimple_min_invariant (t)
3364 || TREE_CODE (t) == SSA_NAME
3365 || t == error_mark_node
3366 || TREE_CODE (t) == IDENTIFIER_NODE)
3369 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3372 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3373 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3374 || TREE_CODE (t) == COMPONENT_REF
3375 || TREE_CODE (t) == REALPART_EXPR
3376 || TREE_CODE (t) == IMAGPART_EXPR)
3377 t = TREE_OPERAND (t, 0);
3386 /* Called via walk_trees. Verify tree sharing. */
3389 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3391 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3393 if (tree_node_can_be_shared (*tp))
3395 *walk_subtrees = false;
3399 if (pointer_set_insert (visited, *tp))
3406 /* Helper function for verify_gimple_tuples. */
3409 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3410 void *data ATTRIBUTE_UNUSED)
3412 switch (TREE_CODE (*tp))
3415 error ("unexpected non-tuple");
3425 /* Verify that there are no trees that should have been converted to
3426 gimple tuples. Return true if T contains a node that should have
3427 been converted to a gimple tuple, but hasn't. */
3430 verify_gimple_tuples (tree t)
3432 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3435 static bool eh_error_found;
3437 verify_eh_throw_stmt_node (void **slot, void *data)
3439 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3440 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3442 if (!pointer_set_contains (visited, node->stmt))
3444 error ("Dead STMT in EH table");
3445 debug_generic_stmt (node->stmt);
3446 eh_error_found = true;
3451 /* Verify the GIMPLE statement chain. */
3457 block_stmt_iterator bsi;
3459 struct pointer_set_t *visited, *visited_stmts;
3462 timevar_push (TV_TREE_STMT_VERIFY);
3463 visited = pointer_set_create ();
3464 visited_stmts = pointer_set_create ();
3471 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3473 int phi_num_args = PHI_NUM_ARGS (phi);
3475 pointer_set_insert (visited_stmts, phi);
3476 if (bb_for_stmt (phi) != bb)
3478 error ("bb_for_stmt (phi) is set to a wrong basic block");
3482 for (i = 0; i < phi_num_args; i++)
3484 tree t = PHI_ARG_DEF (phi, i);
3487 /* Addressable variables do have SSA_NAMEs but they
3488 are not considered gimple values. */
3489 if (TREE_CODE (t) != SSA_NAME
3490 && TREE_CODE (t) != FUNCTION_DECL
3491 && !is_gimple_val (t))
3493 error ("PHI def is not a GIMPLE value");
3494 debug_generic_stmt (phi);
3495 debug_generic_stmt (t);
3499 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3502 debug_generic_stmt (addr);
3506 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3509 error ("incorrect sharing of tree nodes");
3510 debug_generic_stmt (phi);
3511 debug_generic_stmt (addr);
3517 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3519 tree stmt = bsi_stmt (bsi);
3521 pointer_set_insert (visited_stmts, stmt);
3522 err |= verify_gimple_tuples (stmt);
3524 if (bb_for_stmt (stmt) != bb)
3526 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3531 err |= verify_stmt (stmt, bsi_end_p (bsi));
3532 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3535 error ("incorrect sharing of tree nodes");
3536 debug_generic_stmt (stmt);
3537 debug_generic_stmt (addr);
3542 eh_error_found = false;
3543 if (get_eh_throw_stmt_table (cfun))
3544 htab_traverse (get_eh_throw_stmt_table (cfun),
3545 verify_eh_throw_stmt_node,
3548 if (err | eh_error_found)
3549 internal_error ("verify_stmts failed");
3551 pointer_set_destroy (visited);
3552 pointer_set_destroy (visited_stmts);
3553 verify_histograms ();
3554 timevar_pop (TV_TREE_STMT_VERIFY);
3558 /* Verifies that the flow information is OK. */
3561 tree_verify_flow_info (void)
3565 block_stmt_iterator bsi;
3570 if (ENTRY_BLOCK_PTR->il.tree)
3572 error ("ENTRY_BLOCK has IL associated with it");
3576 if (EXIT_BLOCK_PTR->il.tree)
3578 error ("EXIT_BLOCK has IL associated with it");
3582 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3583 if (e->flags & EDGE_FALLTHRU)
3585 error ("fallthru to exit from bb %d", e->src->index);
3591 bool found_ctrl_stmt = false;
3595 /* Skip labels on the start of basic block. */
3596 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3598 tree prev_stmt = stmt;
3600 stmt = bsi_stmt (bsi);
3602 if (TREE_CODE (stmt) != LABEL_EXPR)
3605 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3607 error ("nonlocal label ");
3608 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3609 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3614 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3617 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3618 fprintf (stderr, " to block does not match in bb %d",
3623 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3624 != current_function_decl)
3627 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3628 fprintf (stderr, " has incorrect context in bb %d",
3634 /* Verify that body of basic block BB is free of control flow. */
3635 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3637 tree stmt = bsi_stmt (bsi);
3639 if (found_ctrl_stmt)
3641 error ("control flow in the middle of basic block %d",
3646 if (stmt_ends_bb_p (stmt))
3647 found_ctrl_stmt = true;
3649 if (TREE_CODE (stmt) == LABEL_EXPR)
3652 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3653 fprintf (stderr, " in the middle of basic block %d", bb->index);
3658 bsi = bsi_last (bb);
3659 if (bsi_end_p (bsi))
3662 stmt = bsi_stmt (bsi);
3664 err |= verify_eh_edges (stmt);
3666 if (is_ctrl_stmt (stmt))
3668 FOR_EACH_EDGE (e, ei, bb->succs)
3669 if (e->flags & EDGE_FALLTHRU)
3671 error ("fallthru edge after a control statement in bb %d",
3677 if (TREE_CODE (stmt) != COND_EXPR)
3679 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3680 after anything else but if statement. */
3681 FOR_EACH_EDGE (e, ei, bb->succs)
3682 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3684 error ("true/false edge after a non-COND_EXPR in bb %d",
3690 switch (TREE_CODE (stmt))
3697 if (COND_EXPR_THEN (stmt) != NULL_TREE
3698 || COND_EXPR_ELSE (stmt) != NULL_TREE)
3700 error ("COND_EXPR with code in branches at the end of bb %d",
3705 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3707 if (!true_edge || !false_edge
3708 || !(true_edge->flags & EDGE_TRUE_VALUE)
3709 || !(false_edge->flags & EDGE_FALSE_VALUE)
3710 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3711 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3712 || EDGE_COUNT (bb->succs) >= 3)
3714 error ("wrong outgoing edge flags at end of bb %d",
3722 if (simple_goto_p (stmt))
3724 error ("explicit goto at end of bb %d", bb->index);
3729 /* FIXME. We should double check that the labels in the
3730 destination blocks have their address taken. */
3731 FOR_EACH_EDGE (e, ei, bb->succs)
3732 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3733 | EDGE_FALSE_VALUE))
3734 || !(e->flags & EDGE_ABNORMAL))
3736 error ("wrong outgoing edge flags at end of bb %d",
3744 if (!single_succ_p (bb)
3745 || (single_succ_edge (bb)->flags
3746 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3747 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3749 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3752 if (single_succ (bb) != EXIT_BLOCK_PTR)
3754 error ("return edge does not point to exit in bb %d",
3767 vec = SWITCH_LABELS (stmt);
3768 n = TREE_VEC_LENGTH (vec);
3770 /* Mark all the destination basic blocks. */
3771 for (i = 0; i < n; ++i)
3773 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3774 basic_block label_bb = label_to_block (lab);
3776 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3777 label_bb->aux = (void *)1;
3780 /* Verify that the case labels are sorted. */
3781 prev = TREE_VEC_ELT (vec, 0);
3782 for (i = 1; i < n - 1; ++i)
3784 tree c = TREE_VEC_ELT (vec, i);
3787 error ("found default case not at end of case vector");
3791 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3793 error ("case labels not sorted: ");
3794 print_generic_expr (stderr, prev, 0);
3795 fprintf (stderr," is greater than ");
3796 print_generic_expr (stderr, c, 0);
3797 fprintf (stderr," but comes before it.\n");
3802 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3804 error ("no default case found at end of case vector");
3808 FOR_EACH_EDGE (e, ei, bb->succs)
3812 error ("extra outgoing edge %d->%d",
3813 bb->index, e->dest->index);
3816 e->dest->aux = (void *)2;
3817 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3818 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3820 error ("wrong outgoing edge flags at end of bb %d",
3826 /* Check that we have all of them. */
3827 for (i = 0; i < n; ++i)
3829 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3830 basic_block label_bb = label_to_block (lab);
3832 if (label_bb->aux != (void *)2)
3834 error ("missing edge %i->%i",
3835 bb->index, label_bb->index);
3840 FOR_EACH_EDGE (e, ei, bb->succs)
3841 e->dest->aux = (void *)0;
3848 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3849 verify_dominators (CDI_DOMINATORS);
3855 /* Updates phi nodes after creating a forwarder block joined
3856 by edge FALLTHRU. */
3859 tree_make_forwarder_block (edge fallthru)
3863 basic_block dummy, bb;
3864 tree phi, new_phi, var;
3866 dummy = fallthru->src;
3867 bb = fallthru->dest;
3869 if (single_pred_p (bb))
3872 /* If we redirected a branch we must create new PHI nodes at the
3874 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3876 var = PHI_RESULT (phi);
3877 new_phi = create_phi_node (var, bb);
3878 SSA_NAME_DEF_STMT (var) = new_phi;
3879 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3880 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3883 /* Ensure that the PHI node chain is in the same order. */
3884 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3886 /* Add the arguments we have stored on edges. */
3887 FOR_EACH_EDGE (e, ei, bb->preds)
3892 flush_pending_stmts (e);
3897 /* Return a non-special label in the head of basic block BLOCK.
3898 Create one if it doesn't exist. */
3901 tree_block_label (basic_block bb)
3903 block_stmt_iterator i, s = bsi_start (bb);
3907 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
3909 stmt = bsi_stmt (i);
3910 if (TREE_CODE (stmt) != LABEL_EXPR)
3912 label = LABEL_EXPR_LABEL (stmt);
3913 if (!DECL_NONLOCAL (label))
3916 bsi_move_before (&i, &s);
3921 label = create_artificial_label ();
3922 stmt = build1 (LABEL_EXPR, void_type_node, label);
3923 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
3928 /* Attempt to perform edge redirection by replacing a possibly complex
3929 jump instruction by a goto or by removing the jump completely.
3930 This can apply only if all edges now point to the same block. The
3931 parameters and return values are equivalent to
3932 redirect_edge_and_branch. */
3935 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
3937 basic_block src = e->src;
3938 block_stmt_iterator b;
3941 /* We can replace or remove a complex jump only when we have exactly
3943 if (EDGE_COUNT (src->succs) != 2
3944 /* Verify that all targets will be TARGET. Specifically, the
3945 edge that is not E must also go to TARGET. */
3946 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
3952 stmt = bsi_stmt (b);
3954 if (TREE_CODE (stmt) == COND_EXPR
3955 || TREE_CODE (stmt) == SWITCH_EXPR)
3957 bsi_remove (&b, true);
3958 e = ssa_redirect_edge (e, target);
3959 e->flags = EDGE_FALLTHRU;
3967 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3968 edge representing the redirected branch. */
3971 tree_redirect_edge_and_branch (edge e, basic_block dest)
3973 basic_block bb = e->src;
3974 block_stmt_iterator bsi;
3978 if (e->flags & EDGE_ABNORMAL)
3981 if (e->src != ENTRY_BLOCK_PTR
3982 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
3985 if (e->dest == dest)
3988 label = tree_block_label (dest);
3990 bsi = bsi_last (bb);
3991 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
3993 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
3996 /* For COND_EXPR, we only need to redirect the edge. */
4000 /* No non-abnormal edges should lead from a non-simple goto, and
4001 simple ones should be represented implicitly. */
4006 tree cases = get_cases_for_edge (e, stmt);
4008 /* If we have a list of cases associated with E, then use it
4009 as it's a lot faster than walking the entire case vector. */
4012 edge e2 = find_edge (e->src, dest);
4019 CASE_LABEL (cases) = label;
4020 cases = TREE_CHAIN (cases);
4023 /* If there was already an edge in the CFG, then we need
4024 to move all the cases associated with E to E2. */
4027 tree cases2 = get_cases_for_edge (e2, stmt);
4029 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4030 TREE_CHAIN (cases2) = first;
4035 tree vec = SWITCH_LABELS (stmt);
4036 size_t i, n = TREE_VEC_LENGTH (vec);
4038 for (i = 0; i < n; i++)
4040 tree elt = TREE_VEC_ELT (vec, i);
4042 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4043 CASE_LABEL (elt) = label;
4051 bsi_remove (&bsi, true);
4052 e->flags |= EDGE_FALLTHRU;
4056 /* Otherwise it must be a fallthru edge, and we don't need to
4057 do anything besides redirecting it. */
4058 gcc_assert (e->flags & EDGE_FALLTHRU);
4062 /* Update/insert PHI nodes as necessary. */
4064 /* Now update the edges in the CFG. */
4065 e = ssa_redirect_edge (e, dest);
4070 /* Returns true if it is possible to remove edge E by redirecting
4071 it to the destination of the other edge from E->src. */
4074 tree_can_remove_branch_p (edge e)
4076 if (e->flags & EDGE_ABNORMAL)
4082 /* Simple wrapper, as we can always redirect fallthru edges. */
4085 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4087 e = tree_redirect_edge_and_branch (e, dest);
4094 /* Splits basic block BB after statement STMT (but at least after the
4095 labels). If STMT is NULL, BB is split just after the labels. */
4098 tree_split_block (basic_block bb, void *stmt)
4100 block_stmt_iterator bsi;
4101 tree_stmt_iterator tsi_tgt;
4107 new_bb = create_empty_bb (bb);
4109 /* Redirect the outgoing edges. */
4110 new_bb->succs = bb->succs;
4112 FOR_EACH_EDGE (e, ei, new_bb->succs)
4115 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4118 /* Move everything from BSI to the new basic block. */
4119 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4121 act = bsi_stmt (bsi);
4122 if (TREE_CODE (act) == LABEL_EXPR)
4135 if (bsi_end_p (bsi))
4138 /* Split the statement list - avoid re-creating new containers as this
4139 brings ugly quadratic memory consumption in the inliner.
4140 (We are still quadratic since we need to update stmt BB pointers,
4142 list = tsi_split_statement_list_before (&bsi.tsi);
4143 set_bb_stmt_list (new_bb, list);
4144 for (tsi_tgt = tsi_start (list);
4145 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4146 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4152 /* Moves basic block BB after block AFTER. */
4155 tree_move_block_after (basic_block bb, basic_block after)
4157 if (bb->prev_bb == after)
4161 link_block (bb, after);
4167 /* Return true if basic_block can be duplicated. */
4170 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4176 /* Create a duplicate of the basic block BB. NOTE: This does not
4177 preserve SSA form. */
4180 tree_duplicate_bb (basic_block bb)
4183 block_stmt_iterator bsi, bsi_tgt;
4186 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4188 /* Copy the PHI nodes. We ignore PHI node arguments here because
4189 the incoming edges have not been setup yet. */
4190 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4192 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4193 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4196 /* Keep the chain of PHI nodes in the same order so that they can be
4197 updated by ssa_redirect_edge. */
4198 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4200 bsi_tgt = bsi_start (new_bb);
4201 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4203 def_operand_p def_p;
4204 ssa_op_iter op_iter;
4208 stmt = bsi_stmt (bsi);
4209 if (TREE_CODE (stmt) == LABEL_EXPR)
4212 /* Create a new copy of STMT and duplicate STMT's virtual
4214 copy = unshare_expr (stmt);
4215 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4216 copy_virtual_operands (copy, stmt);
4217 region = lookup_stmt_eh_region (stmt);
4219 add_stmt_to_eh_region (copy, region);
4220 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4222 /* Create new names for all the definitions created by COPY and
4223 add replacement mappings for each new name. */
4224 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4225 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4232 /* Basic block BB_COPY was created by code duplication. Add phi node
4233 arguments for edges going out of BB_COPY. The blocks that were
4234 duplicated have BB_DUPLICATED set. */
4237 add_phi_args_after_copy_bb (basic_block bb_copy)
4239 basic_block bb, dest;
4242 tree phi, phi_copy, phi_next, def;
4244 bb = get_bb_original (bb_copy);
4246 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4248 if (!phi_nodes (e_copy->dest))
4251 if (e_copy->dest->flags & BB_DUPLICATED)
4252 dest = get_bb_original (e_copy->dest);
4254 dest = e_copy->dest;
4256 e = find_edge (bb, dest);
4259 /* During loop unrolling the target of the latch edge is copied.
4260 In this case we are not looking for edge to dest, but to
4261 duplicated block whose original was dest. */
4262 FOR_EACH_EDGE (e, ei, bb->succs)
4263 if ((e->dest->flags & BB_DUPLICATED)
4264 && get_bb_original (e->dest) == dest)
4267 gcc_assert (e != NULL);
4270 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4272 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4274 phi_next = PHI_CHAIN (phi);
4275 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4276 add_phi_arg (phi_copy, def, e_copy);
4281 /* Blocks in REGION_COPY array of length N_REGION were created by
4282 duplication of basic blocks. Add phi node arguments for edges
4283 going from these blocks. */
4286 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4290 for (i = 0; i < n_region; i++)
4291 region_copy[i]->flags |= BB_DUPLICATED;
4293 for (i = 0; i < n_region; i++)
4294 add_phi_args_after_copy_bb (region_copy[i]);
4296 for (i = 0; i < n_region; i++)
4297 region_copy[i]->flags &= ~BB_DUPLICATED;
4300 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4301 important exit edge EXIT. By important we mean that no SSA name defined
4302 inside region is live over the other exit edges of the region. All entry
4303 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4304 to the duplicate of the region. SSA form, dominance and loop information
4305 is updated. The new basic blocks are stored to REGION_COPY in the same
4306 order as they had in REGION, provided that REGION_COPY is not NULL.
4307 The function returns false if it is unable to copy the region,
4311 tree_duplicate_sese_region (edge entry, edge exit,
4312 basic_block *region, unsigned n_region,
4313 basic_block *region_copy)
4316 bool free_region_copy = false, copying_header = false;
4317 struct loop *loop = entry->dest->loop_father;
4321 int total_freq = 0, entry_freq = 0;
4322 gcov_type total_count = 0, entry_count = 0;
4324 if (!can_copy_bbs_p (region, n_region))
4327 /* Some sanity checking. Note that we do not check for all possible
4328 missuses of the functions. I.e. if you ask to copy something weird,
4329 it will work, but the state of structures probably will not be
4331 for (i = 0; i < n_region; i++)
4333 /* We do not handle subloops, i.e. all the blocks must belong to the
4335 if (region[i]->loop_father != loop)
4338 if (region[i] != entry->dest
4339 && region[i] == loop->header)
4345 /* In case the function is used for loop header copying (which is the primary
4346 use), ensure that EXIT and its copy will be new latch and entry edges. */
4347 if (loop->header == entry->dest)
4349 copying_header = true;
4350 loop->copy = loop->outer;
4352 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4355 for (i = 0; i < n_region; i++)
4356 if (region[i] != exit->src
4357 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4363 region_copy = XNEWVEC (basic_block, n_region);
4364 free_region_copy = true;
4367 gcc_assert (!need_ssa_update_p ());
4369 /* Record blocks outside the region that are dominated by something
4371 doms = XNEWVEC (basic_block, n_basic_blocks);
4372 initialize_original_copy_tables ();
4374 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4376 if (entry->dest->count)
4378 total_count = entry->dest->count;
4379 entry_count = entry->count;
4380 /* Fix up corner cases, to avoid division by zero or creation of negative
4382 if (entry_count > total_count)
4383 entry_count = total_count;
4387 total_freq = entry->dest->frequency;
4388 entry_freq = EDGE_FREQUENCY (entry);
4389 /* Fix up corner cases, to avoid division by zero or creation of negative
4391 if (total_freq == 0)
4393 else if (entry_freq > total_freq)
4394 entry_freq = total_freq;
4397 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4398 split_edge_bb_loc (entry));
4401 scale_bbs_frequencies_gcov_type (region, n_region,
4402 total_count - entry_count,
4404 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4409 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4411 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4416 loop->header = exit->dest;
4417 loop->latch = exit->src;
4420 /* Redirect the entry and add the phi node arguments. */
4421 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4422 gcc_assert (redirected != NULL);
4423 flush_pending_stmts (entry);
4425 /* Concerning updating of dominators: We must recount dominators
4426 for entry block and its copy. Anything that is outside of the
4427 region, but was dominated by something inside needs recounting as
4429 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4430 doms[n_doms++] = get_bb_original (entry->dest);
4431 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4434 /* Add the other PHI node arguments. */
4435 add_phi_args_after_copy (region_copy, n_region);
4437 /* Update the SSA web. */
4438 update_ssa (TODO_update_ssa);
4440 if (free_region_copy)
4443 free_original_copy_tables ();
4448 DEF_VEC_P(basic_block);
4449 DEF_VEC_ALLOC_P(basic_block,heap);
4452 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4453 adding blocks when the dominator traversal reaches EXIT. This
4454 function silently assumes that ENTRY strictly dominates EXIT. */
4457 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4458 VEC(basic_block,heap) **bbs_p)
4462 for (son = first_dom_son (CDI_DOMINATORS, entry);
4464 son = next_dom_son (CDI_DOMINATORS, son))
4466 VEC_safe_push (basic_block, heap, *bbs_p, son);
4468 gather_blocks_in_sese_region (son, exit, bbs_p);
4478 bitmap vars_to_remove;
4479 htab_t new_label_map;
4483 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4484 contained in *TP and change the DECL_CONTEXT of every local
4485 variable referenced in *TP. */
4488 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4490 struct move_stmt_d *p = (struct move_stmt_d *) data;
4494 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4495 TREE_BLOCK (t) = p->block;
4497 if (OMP_DIRECTIVE_P (t)
4498 && TREE_CODE (t) != OMP_RETURN
4499 && TREE_CODE (t) != OMP_CONTINUE)
4501 /* Do not remap variables inside OMP directives. Variables
4502 referenced in clauses and directive header belong to the
4503 parent function and should not be moved into the child
4505 bool save_remap_decls_p = p->remap_decls_p;
4506 p->remap_decls_p = false;
4509 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4511 p->remap_decls_p = save_remap_decls_p;
4513 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4515 if (TREE_CODE (t) == LABEL_DECL)
4517 if (p->new_label_map)
4519 struct tree_map in, *out;
4521 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4526 DECL_CONTEXT (t) = p->to_context;
4528 else if (p->remap_decls_p)
4530 DECL_CONTEXT (t) = p->to_context;
4532 if (TREE_CODE (t) == VAR_DECL)
4534 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4535 f->unexpanded_var_list
4536 = tree_cons (0, t, f->unexpanded_var_list);
4538 /* Mark T to be removed from the original function,
4539 otherwise it will be given a DECL_RTL when the
4540 original function is expanded. */
4541 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4545 else if (TYPE_P (t))
4552 /* Move basic block BB from function CFUN to function DEST_FN. The
4553 block is moved out of the original linked list and placed after
4554 block AFTER in the new list. Also, the block is removed from the
4555 original array of blocks and placed in DEST_FN's array of blocks.
4556 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4557 updated to reflect the moved edges.
4559 On exit, local variables that need to be removed from
4560 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4563 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4564 basic_block after, bool update_edge_count_p,
4565 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4567 struct control_flow_graph *cfg;
4570 block_stmt_iterator si;
4571 struct move_stmt_d d;
4572 unsigned old_len, new_len;
4574 /* Remove BB from dominance structures. */
4575 delete_from_dominance_info (CDI_DOMINATORS, bb);
4577 /* Link BB to the new linked list. */
4578 move_block_after (bb, after);
4580 /* Update the edge count in the corresponding flowgraphs. */
4581 if (update_edge_count_p)
4582 FOR_EACH_EDGE (e, ei, bb->succs)
4584 cfun->cfg->x_n_edges--;
4585 dest_cfun->cfg->x_n_edges++;
4588 /* Remove BB from the original basic block array. */
4589 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4590 cfun->cfg->x_n_basic_blocks--;
4592 /* Grow DEST_CFUN's basic block array if needed. */
4593 cfg = dest_cfun->cfg;
4594 cfg->x_n_basic_blocks++;
4595 if (bb->index >= cfg->x_last_basic_block)
4596 cfg->x_last_basic_block = bb->index + 1;
4598 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4599 if ((unsigned) cfg->x_last_basic_block >= old_len)
4601 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4602 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4606 VEC_replace (basic_block, cfg->x_basic_block_info,
4607 cfg->x_last_basic_block, bb);
4609 /* The statements in BB need to be associated with a new TREE_BLOCK.
4610 Labels need to be associated with a new label-to-block map. */
4611 memset (&d, 0, sizeof (d));
4612 d.vars_to_remove = vars_to_remove;
4614 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4616 tree stmt = bsi_stmt (si);
4619 d.from_context = cfun->decl;
4620 d.to_context = dest_cfun->decl;
4621 d.remap_decls_p = true;
4622 d.new_label_map = new_label_map;
4623 if (TREE_BLOCK (stmt))
4624 d.block = DECL_INITIAL (dest_cfun->decl);
4626 walk_tree (&stmt, move_stmt_r, &d, NULL);
4628 if (TREE_CODE (stmt) == LABEL_EXPR)
4630 tree label = LABEL_EXPR_LABEL (stmt);
4631 int uid = LABEL_DECL_UID (label);
4633 gcc_assert (uid > -1);
4635 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4636 if (old_len <= (unsigned) uid)
4638 new_len = 3 * uid / 2;
4639 VEC_safe_grow_cleared (basic_block, gc,
4640 cfg->x_label_to_block_map, new_len);
4643 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4644 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4646 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4648 if (uid >= dest_cfun->last_label_uid)
4649 dest_cfun->last_label_uid = uid + 1;
4651 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4652 TREE_OPERAND (stmt, 0) =
4653 build_int_cst (NULL_TREE,
4654 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4657 region = lookup_stmt_eh_region (stmt);
4660 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4661 remove_stmt_from_eh_region (stmt);
4662 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4663 gimple_remove_stmt_histograms (cfun, stmt);
4668 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4669 the outermost EH region. Use REGION as the incoming base EH region. */
4672 find_outermost_region_in_block (struct function *src_cfun,
4673 basic_block bb, int region)
4675 block_stmt_iterator si;
4677 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4679 tree stmt = bsi_stmt (si);
4682 if (TREE_CODE (stmt) == RESX_EXPR)
4683 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4685 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4686 if (stmt_region > 0)
4689 region = stmt_region;
4690 else if (stmt_region != region)
4692 region = eh_region_outermost (src_cfun, stmt_region, region);
4693 gcc_assert (region != -1);
4702 new_label_mapper (tree decl, void *data)
4704 htab_t hash = (htab_t) data;
4708 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4710 m = xmalloc (sizeof (struct tree_map));
4711 m->hash = DECL_UID (decl);
4712 m->base.from = decl;
4713 m->to = create_artificial_label ();
4714 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4716 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4717 gcc_assert (*slot == NULL);
4724 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4725 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4726 single basic block in the original CFG and the new basic block is
4727 returned. DEST_CFUN must not have a CFG yet.
4729 Note that the region need not be a pure SESE region. Blocks inside
4730 the region may contain calls to abort/exit. The only restriction
4731 is that ENTRY_BB should be the only entry point and it must
4734 All local variables referenced in the region are assumed to be in
4735 the corresponding BLOCK_VARS and unexpanded variable lists
4736 associated with DEST_CFUN. */
4739 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4740 basic_block exit_bb)
4742 VEC(basic_block,heap) *bbs;
4743 basic_block after, bb, *entry_pred, *exit_succ;
4744 struct function *saved_cfun;
4745 int *entry_flag, *exit_flag, eh_offset;
4746 unsigned i, num_entry_edges, num_exit_edges;
4749 bitmap vars_to_remove;
4750 htab_t new_label_map;
4754 /* Collect all the blocks in the region. Manually add ENTRY_BB
4755 because it won't be added by dfs_enumerate_from. */
4756 calculate_dominance_info (CDI_DOMINATORS);
4758 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4760 gcc_assert (entry_bb != exit_bb
4762 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4765 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4766 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4768 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4769 the predecessor edges to ENTRY_BB and the successor edges to
4770 EXIT_BB so that we can re-attach them to the new basic block that
4771 will replace the region. */
4772 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4773 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4774 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4776 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4778 entry_flag[i] = e->flags;
4779 entry_pred[i++] = e->src;
4785 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4786 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4787 sizeof (basic_block));
4788 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4790 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4792 exit_flag[i] = e->flags;
4793 exit_succ[i++] = e->dest;
4804 /* Switch context to the child function to initialize DEST_FN's CFG. */
4805 gcc_assert (dest_cfun->cfg == NULL);
4808 init_empty_tree_cfg ();
4810 /* Initialize EH information for the new function. */
4812 new_label_map = NULL;
4817 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4818 region = find_outermost_region_in_block (saved_cfun, bb, region);
4820 init_eh_for_function ();
4823 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4824 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4825 new_label_map, region, 0);
4831 /* Move blocks from BBS into DEST_CFUN. */
4832 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4833 after = dest_cfun->cfg->x_entry_block_ptr;
4834 vars_to_remove = BITMAP_ALLOC (NULL);
4835 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4837 /* No need to update edge counts on the last block. It has
4838 already been updated earlier when we detached the region from
4839 the original CFG. */
4840 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4841 new_label_map, eh_offset);
4846 htab_delete (new_label_map);
4848 /* Remove the variables marked in VARS_TO_REMOVE from
4849 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4850 DECL_RTL in the context of CFUN. */
4851 if (!bitmap_empty_p (vars_to_remove))
4855 for (p = &cfun->unexpanded_var_list; *p; )
4857 tree var = TREE_VALUE (*p);
4858 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4860 *p = TREE_CHAIN (*p);
4864 p = &TREE_CHAIN (*p);
4868 BITMAP_FREE (vars_to_remove);
4870 /* Rewire the entry and exit blocks. The successor to the entry
4871 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4872 the child function. Similarly, the predecessor of DEST_FN's
4873 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4874 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4875 various CFG manipulation function get to the right CFG.
4877 FIXME, this is silly. The CFG ought to become a parameter to
4880 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4882 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4885 /* Back in the original function, the SESE region has disappeared,
4886 create a new basic block in its place. */
4887 bb = create_empty_bb (entry_pred[0]);
4888 for (i = 0; i < num_entry_edges; i++)
4889 make_edge (entry_pred[i], bb, entry_flag[i]);
4891 for (i = 0; i < num_exit_edges; i++)
4892 make_edge (bb, exit_succ[i], exit_flag[i]);
4901 free_dominance_info (CDI_DOMINATORS);
4902 free_dominance_info (CDI_POST_DOMINATORS);
4903 VEC_free (basic_block, heap, bbs);
4909 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4912 dump_function_to_file (tree fn, FILE *file, int flags)
4914 tree arg, vars, var;
4915 struct function *dsf;
4916 bool ignore_topmost_bind = false, any_var = false;
4919 struct function *saved_cfun;
4921 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
4923 arg = DECL_ARGUMENTS (fn);
4926 print_generic_expr (file, arg, dump_flags);
4927 if (TREE_CHAIN (arg))
4928 fprintf (file, ", ");
4929 arg = TREE_CHAIN (arg);
4931 fprintf (file, ")\n");
4933 dsf = DECL_STRUCT_FUNCTION (fn);
4934 if (dsf && (flags & TDF_DETAILS))
4935 dump_eh_tree (file, dsf);
4937 if (flags & TDF_RAW)
4939 dump_node (fn, TDF_SLIM | flags, file);
4943 /* Switch CFUN to point to FN. */
4945 cfun = DECL_STRUCT_FUNCTION (fn);
4947 /* When GIMPLE is lowered, the variables are no longer available in
4948 BIND_EXPRs, so display them separately. */
4949 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
4951 ignore_topmost_bind = true;
4953 fprintf (file, "{\n");
4954 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
4956 var = TREE_VALUE (vars);
4958 print_generic_decl (file, var, flags);
4959 fprintf (file, "\n");
4965 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
4967 /* Make a CFG based dump. */
4968 check_bb_profile (ENTRY_BLOCK_PTR, file);
4969 if (!ignore_topmost_bind)
4970 fprintf (file, "{\n");
4972 if (any_var && n_basic_blocks)
4973 fprintf (file, "\n");
4976 dump_generic_bb (file, bb, 2, flags);
4978 fprintf (file, "}\n");
4979 check_bb_profile (EXIT_BLOCK_PTR, file);
4985 /* Make a tree based dump. */
4986 chain = DECL_SAVED_TREE (fn);
4988 if (chain && TREE_CODE (chain) == BIND_EXPR)
4990 if (ignore_topmost_bind)
4992 chain = BIND_EXPR_BODY (chain);
5000 if (!ignore_topmost_bind)
5001 fprintf (file, "{\n");
5006 fprintf (file, "\n");
5008 print_generic_stmt_indented (file, chain, flags, indent);
5009 if (ignore_topmost_bind)
5010 fprintf (file, "}\n");
5013 fprintf (file, "\n\n");
5020 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5023 debug_function (tree fn, int flags)
5025 dump_function_to_file (fn, stderr, flags);
5029 /* Pretty print of the loops intermediate representation. */
5030 static void print_loop (FILE *, struct loop *, int);
5031 static void print_pred_bbs (FILE *, basic_block bb);
5032 static void print_succ_bbs (FILE *, basic_block bb);
5035 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5038 print_pred_bbs (FILE *file, basic_block bb)
5043 FOR_EACH_EDGE (e, ei, bb->preds)
5044 fprintf (file, "bb_%d ", e->src->index);
5048 /* Print on FILE the indexes for the successors of basic_block BB. */
5051 print_succ_bbs (FILE *file, basic_block bb)
5056 FOR_EACH_EDGE (e, ei, bb->succs)
5057 fprintf (file, "bb_%d ", e->dest->index);
5061 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5064 print_loop (FILE *file, struct loop *loop, int indent)
5072 s_indent = (char *) alloca ((size_t) indent + 1);
5073 memset ((void *) s_indent, ' ', (size_t) indent);
5074 s_indent[indent] = '\0';
5076 /* Print the loop's header. */
5077 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5079 /* Print the loop's body. */
5080 fprintf (file, "%s{\n", s_indent);
5082 if (bb->loop_father == loop)
5084 /* Print the basic_block's header. */
5085 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5086 print_pred_bbs (file, bb);
5087 fprintf (file, "}, succs = {");
5088 print_succ_bbs (file, bb);
5089 fprintf (file, "})\n");
5091 /* Print the basic_block's body. */
5092 fprintf (file, "%s {\n", s_indent);
5093 tree_dump_bb (bb, file, indent + 4);
5094 fprintf (file, "%s }\n", s_indent);
5097 print_loop (file, loop->inner, indent + 2);
5098 fprintf (file, "%s}\n", s_indent);
5099 print_loop (file, loop->next, indent);
5103 /* Follow a CFG edge from the entry point of the program, and on entry
5104 of a loop, pretty print the loop structure on FILE. */
5107 print_loop_ir (FILE *file)
5111 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5112 if (bb && bb->loop_father)
5113 print_loop (file, bb->loop_father, 0);
5117 /* Debugging loops structure at tree level. */
5120 debug_loop_ir (void)
5122 print_loop_ir (stderr);
5126 /* Return true if BB ends with a call, possibly followed by some
5127 instructions that must stay with the call. Return false,
5131 tree_block_ends_with_call_p (basic_block bb)
5133 block_stmt_iterator bsi = bsi_last (bb);
5134 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5138 /* Return true if BB ends with a conditional branch. Return false,
5142 tree_block_ends_with_condjump_p (basic_block bb)
5144 tree stmt = last_stmt (bb);
5145 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5149 /* Return true if we need to add fake edge to exit at statement T.
5150 Helper function for tree_flow_call_edges_add. */
5153 need_fake_edge_p (tree t)
5157 /* NORETURN and LONGJMP calls already have an edge to exit.
5158 CONST and PURE calls do not need one.
5159 We don't currently check for CONST and PURE here, although
5160 it would be a good idea, because those attributes are
5161 figured out from the RTL in mark_constant_function, and
5162 the counter incrementation code from -fprofile-arcs
5163 leads to different results from -fbranch-probabilities. */
5164 call = get_call_expr_in (t);
5166 && !(call_expr_flags (call) & ECF_NORETURN))
5169 if (TREE_CODE (t) == ASM_EXPR
5170 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5177 /* Add fake edges to the function exit for any non constant and non
5178 noreturn calls, volatile inline assembly in the bitmap of blocks
5179 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5180 the number of blocks that were split.
5182 The goal is to expose cases in which entering a basic block does
5183 not imply that all subsequent instructions must be executed. */
5186 tree_flow_call_edges_add (sbitmap blocks)
5189 int blocks_split = 0;
5190 int last_bb = last_basic_block;
5191 bool check_last_block = false;
5193 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5197 check_last_block = true;
5199 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5201 /* In the last basic block, before epilogue generation, there will be
5202 a fallthru edge to EXIT. Special care is required if the last insn
5203 of the last basic block is a call because make_edge folds duplicate
5204 edges, which would result in the fallthru edge also being marked
5205 fake, which would result in the fallthru edge being removed by
5206 remove_fake_edges, which would result in an invalid CFG.
5208 Moreover, we can't elide the outgoing fake edge, since the block
5209 profiler needs to take this into account in order to solve the minimal
5210 spanning tree in the case that the call doesn't return.
5212 Handle this by adding a dummy instruction in a new last basic block. */
5213 if (check_last_block)
5215 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5216 block_stmt_iterator bsi = bsi_last (bb);
5218 if (!bsi_end_p (bsi))
5221 if (t && need_fake_edge_p (t))
5225 e = find_edge (bb, EXIT_BLOCK_PTR);
5228 bsi_insert_on_edge (e, build_empty_stmt ());
5229 bsi_commit_edge_inserts ();
5234 /* Now add fake edges to the function exit for any non constant
5235 calls since there is no way that we can determine if they will
5237 for (i = 0; i < last_bb; i++)
5239 basic_block bb = BASIC_BLOCK (i);
5240 block_stmt_iterator bsi;
5241 tree stmt, last_stmt;
5246 if (blocks && !TEST_BIT (blocks, i))
5249 bsi = bsi_last (bb);
5250 if (!bsi_end_p (bsi))
5252 last_stmt = bsi_stmt (bsi);
5255 stmt = bsi_stmt (bsi);
5256 if (need_fake_edge_p (stmt))
5259 /* The handling above of the final block before the
5260 epilogue should be enough to verify that there is
5261 no edge to the exit block in CFG already.
5262 Calling make_edge in such case would cause us to
5263 mark that edge as fake and remove it later. */
5264 #ifdef ENABLE_CHECKING
5265 if (stmt == last_stmt)
5267 e = find_edge (bb, EXIT_BLOCK_PTR);
5268 gcc_assert (e == NULL);
5272 /* Note that the following may create a new basic block
5273 and renumber the existing basic blocks. */
5274 if (stmt != last_stmt)
5276 e = split_block (bb, stmt);
5280 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5284 while (!bsi_end_p (bsi));
5289 verify_flow_info ();
5291 return blocks_split;
5294 /* Purge dead abnormal call edges from basic block BB. */
5297 tree_purge_dead_abnormal_call_edges (basic_block bb)
5299 bool changed = tree_purge_dead_eh_edges (bb);
5301 if (current_function_has_nonlocal_label)
5303 tree stmt = last_stmt (bb);
5307 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5308 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5310 if (e->flags & EDGE_ABNORMAL)
5319 /* See tree_purge_dead_eh_edges below. */
5321 free_dominance_info (CDI_DOMINATORS);
5327 /* Stores all basic blocks dominated by BB to DOM_BBS. */
5330 get_all_dominated_blocks (basic_block bb, VEC (basic_block, heap) **dom_bbs)
5334 VEC_safe_push (basic_block, heap, *dom_bbs, bb);
5335 for (son = first_dom_son (CDI_DOMINATORS, bb);
5337 son = next_dom_son (CDI_DOMINATORS, son))
5338 get_all_dominated_blocks (son, dom_bbs);
5341 /* Removes edge E and all the blocks dominated by it, and updates dominance
5342 information. The IL in E->src needs to be updated separately.
5343 If dominance info is not available, only the edge E is removed.*/
5346 remove_edge_and_dominated_blocks (edge e)
5348 VEC (basic_block, heap) *bbs_to_remove = NULL;
5349 VEC (basic_block, heap) *bbs_to_fix_dom = NULL;
5353 bool none_removed = false;
5355 basic_block bb, dbb;
5358 if (!dom_computed[CDI_DOMINATORS])
5364 /* No updating is needed for edges to exit. */
5365 if (e->dest == EXIT_BLOCK_PTR)
5367 if (cfgcleanup_altered_bbs)
5368 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5373 /* First, we find the basic blocks to remove. If E->dest has a predecessor
5374 that is not dominated by E->dest, then this set is empty. Otherwise,
5375 all the basic blocks dominated by E->dest are removed.
5377 Also, to DF_IDOM we store the immediate dominators of the blocks in
5378 the dominance frontier of E (i.e., of the successors of the
5379 removed blocks, if there are any, and of E->dest otherwise). */
5380 FOR_EACH_EDGE (f, ei, e->dest->preds)
5385 if (!dominated_by_p (CDI_DOMINATORS, f->src, e->dest))
5387 none_removed = true;
5392 df = BITMAP_ALLOC (NULL);
5393 df_idom = BITMAP_ALLOC (NULL);
5396 bitmap_set_bit (df_idom,
5397 get_immediate_dominator (CDI_DOMINATORS, e->dest)->index);
5400 get_all_dominated_blocks (e->dest, &bbs_to_remove);
5401 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5403 FOR_EACH_EDGE (f, ei, bb->succs)
5405 if (f->dest != EXIT_BLOCK_PTR)
5406 bitmap_set_bit (df, f->dest->index);
5409 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5410 bitmap_clear_bit (df, bb->index);
5412 EXECUTE_IF_SET_IN_BITMAP (df, 0, i, bi)
5414 bb = BASIC_BLOCK (i);
5415 bitmap_set_bit (df_idom,
5416 get_immediate_dominator (CDI_DOMINATORS, bb)->index);
5420 if (cfgcleanup_altered_bbs)
5422 /* Record the set of the altered basic blocks. */
5423 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5424 bitmap_ior_into (cfgcleanup_altered_bbs, df);
5427 /* Remove E and the cancelled blocks. */
5432 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5433 delete_basic_block (bb);
5436 /* Update the dominance information. The immediate dominator may change only
5437 for blocks whose immediate dominator belongs to DF_IDOM:
5439 Suppose that idom(X) = Y before removal of E and idom(X) != Y after the
5440 removal. Let Z the arbitrary block such that idom(Z) = Y and
5441 Z dominates X after the removal. Before removal, there exists a path P
5442 from Y to X that avoids Z. Let F be the last edge on P that is
5443 removed, and let W = F->dest. Before removal, idom(W) = Y (since Y
5444 dominates W, and because of P, Z does not dominate W), and W belongs to
5445 the dominance frontier of E. Therefore, Y belongs to DF_IDOM. */
5446 EXECUTE_IF_SET_IN_BITMAP (df_idom, 0, i, bi)
5448 bb = BASIC_BLOCK (i);
5449 for (dbb = first_dom_son (CDI_DOMINATORS, bb);
5451 dbb = next_dom_son (CDI_DOMINATORS, dbb))
5452 VEC_safe_push (basic_block, heap, bbs_to_fix_dom, dbb);
5455 iterate_fix_dominators (CDI_DOMINATORS,
5456 VEC_address (basic_block, bbs_to_fix_dom),
5457 VEC_length (basic_block, bbs_to_fix_dom));
5460 BITMAP_FREE (df_idom);
5461 VEC_free (basic_block, heap, bbs_to_remove);
5462 VEC_free (basic_block, heap, bbs_to_fix_dom);
5465 /* Purge dead EH edges from basic block BB. */
5468 tree_purge_dead_eh_edges (basic_block bb)
5470 bool changed = false;
5473 tree stmt = last_stmt (bb);
5475 if (stmt && tree_can_throw_internal (stmt))
5478 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5480 if (e->flags & EDGE_EH)
5482 remove_edge_and_dominated_blocks (e);
5493 tree_purge_all_dead_eh_edges (bitmap blocks)
5495 bool changed = false;
5499 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5501 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5507 /* This function is called whenever a new edge is created or
5511 tree_execute_on_growing_pred (edge e)
5513 basic_block bb = e->dest;
5516 reserve_phi_args_for_new_edge (bb);
5519 /* This function is called immediately before edge E is removed from
5520 the edge vector E->dest->preds. */
5523 tree_execute_on_shrinking_pred (edge e)
5525 if (phi_nodes (e->dest))
5526 remove_phi_args (e);
5529 /*---------------------------------------------------------------------------
5530 Helper functions for Loop versioning
5531 ---------------------------------------------------------------------------*/
5533 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5534 of 'first'. Both of them are dominated by 'new_head' basic block. When
5535 'new_head' was created by 'second's incoming edge it received phi arguments
5536 on the edge by split_edge(). Later, additional edge 'e' was created to
5537 connect 'new_head' and 'first'. Now this routine adds phi args on this
5538 additional edge 'e' that new_head to second edge received as part of edge
5543 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5544 basic_block new_head, edge e)
5547 edge e2 = find_edge (new_head, second);
5549 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5550 edge, we should always have an edge from NEW_HEAD to SECOND. */
5551 gcc_assert (e2 != NULL);
5553 /* Browse all 'second' basic block phi nodes and add phi args to
5554 edge 'e' for 'first' head. PHI args are always in correct order. */
5556 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5558 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5560 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5561 add_phi_arg (phi1, def, e);
5565 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5566 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5567 the destination of the ELSE part. */
5569 tree_lv_add_condition_to_bb (basic_block first_head ATTRIBUTE_UNUSED,
5570 basic_block second_head ATTRIBUTE_UNUSED,
5571 basic_block cond_bb, void *cond_e)
5573 block_stmt_iterator bsi;
5574 tree new_cond_expr = NULL_TREE;
5575 tree cond_expr = (tree) cond_e;
5578 /* Build new conditional expr */
5579 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr,
5580 NULL_TREE, NULL_TREE);
5582 /* Add new cond in cond_bb. */
5583 bsi = bsi_start (cond_bb);
5584 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5585 /* Adjust edges appropriately to connect new head with first head
5586 as well as second head. */
5587 e0 = single_succ_edge (cond_bb);
5588 e0->flags &= ~EDGE_FALLTHRU;
5589 e0->flags |= EDGE_FALSE_VALUE;
5592 struct cfg_hooks tree_cfg_hooks = {
5594 tree_verify_flow_info,
5595 tree_dump_bb, /* dump_bb */
5596 create_bb, /* create_basic_block */
5597 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5598 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5599 tree_can_remove_branch_p, /* can_remove_branch_p */
5600 remove_bb, /* delete_basic_block */
5601 tree_split_block, /* split_block */
5602 tree_move_block_after, /* move_block_after */
5603 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5604 tree_merge_blocks, /* merge_blocks */
5605 tree_predict_edge, /* predict_edge */
5606 tree_predicted_by_p, /* predicted_by_p */
5607 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5608 tree_duplicate_bb, /* duplicate_block */
5609 tree_split_edge, /* split_edge */
5610 tree_make_forwarder_block, /* make_forward_block */
5611 NULL, /* tidy_fallthru_edge */
5612 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5613 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5614 tree_flow_call_edges_add, /* flow_call_edges_add */
5615 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5616 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5617 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5618 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5619 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5620 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5621 flush_pending_stmts /* flush_pending_stmts */
5625 /* Split all critical edges. */
5628 split_critical_edges (void)
5634 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5635 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5636 mappings around the calls to split_edge. */
5637 start_recording_case_labels ();
5640 FOR_EACH_EDGE (e, ei, bb->succs)
5641 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5646 end_recording_case_labels ();
5650 struct tree_opt_pass pass_split_crit_edges =
5652 "crited", /* name */
5654 split_critical_edges, /* execute */
5657 0, /* static_pass_number */
5658 TV_TREE_SPLIT_EDGES, /* tv_id */
5659 PROP_cfg, /* properties required */
5660 PROP_no_crit_edges, /* properties_provided */
5661 0, /* properties_destroyed */
5662 0, /* todo_flags_start */
5663 TODO_dump_func, /* todo_flags_finish */
5668 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5669 a temporary, make sure and register it to be renamed if necessary,
5670 and finally return the temporary. Put the statements to compute
5671 EXP before the current statement in BSI. */
5674 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5676 tree t, new_stmt, orig_stmt;
5678 if (is_gimple_val (exp))
5681 t = make_rename_temp (type, NULL);
5682 new_stmt = build_gimple_modify_stmt (t, exp);
5684 orig_stmt = bsi_stmt (*bsi);
5685 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5686 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5688 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5689 if (gimple_in_ssa_p (cfun))
5690 mark_symbols_for_renaming (new_stmt);
5695 /* Build a ternary operation and gimplify it. Emit code before BSI.
5696 Return the gimple_val holding the result. */
5699 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5700 tree type, tree a, tree b, tree c)
5704 ret = fold_build3 (code, type, a, b, c);
5707 return gimplify_val (bsi, type, ret);
5710 /* Build a binary operation and gimplify it. Emit code before BSI.
5711 Return the gimple_val holding the result. */
5714 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5715 tree type, tree a, tree b)
5719 ret = fold_build2 (code, type, a, b);
5722 return gimplify_val (bsi, type, ret);
5725 /* Build a unary operation and gimplify it. Emit code before BSI.
5726 Return the gimple_val holding the result. */
5729 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5734 ret = fold_build1 (code, type, a);
5737 return gimplify_val (bsi, type, ret);
5742 /* Emit return warnings. */
5745 execute_warn_function_return (void)
5747 #ifdef USE_MAPPED_LOCATION
5748 source_location location;
5756 /* If we have a path to EXIT, then we do return. */
5757 if (TREE_THIS_VOLATILE (cfun->decl)
5758 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5760 #ifdef USE_MAPPED_LOCATION
5761 location = UNKNOWN_LOCATION;
5765 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5767 last = last_stmt (e->src);
5768 if (TREE_CODE (last) == RETURN_EXPR
5769 #ifdef USE_MAPPED_LOCATION
5770 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5772 && (locus = EXPR_LOCUS (last)) != NULL)
5776 #ifdef USE_MAPPED_LOCATION
5777 if (location == UNKNOWN_LOCATION)
5778 location = cfun->function_end_locus;
5779 warning (0, "%H%<noreturn%> function does return", &location);
5782 locus = &cfun->function_end_locus;
5783 warning (0, "%H%<noreturn%> function does return", locus);
5787 /* If we see "return;" in some basic block, then we do reach the end
5788 without returning a value. */
5789 else if (warn_return_type
5790 && !TREE_NO_WARNING (cfun->decl)
5791 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5792 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5794 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5796 tree last = last_stmt (e->src);
5797 if (TREE_CODE (last) == RETURN_EXPR
5798 && TREE_OPERAND (last, 0) == NULL
5799 && !TREE_NO_WARNING (last))
5801 #ifdef USE_MAPPED_LOCATION
5802 location = EXPR_LOCATION (last);
5803 if (location == UNKNOWN_LOCATION)
5804 location = cfun->function_end_locus;
5805 warning (0, "%Hcontrol reaches end of non-void function", &location);
5807 locus = EXPR_LOCUS (last);
5809 locus = &cfun->function_end_locus;
5810 warning (0, "%Hcontrol reaches end of non-void function", locus);
5812 TREE_NO_WARNING (cfun->decl) = 1;
5821 /* Given a basic block B which ends with a conditional and has
5822 precisely two successors, determine which of the edges is taken if
5823 the conditional is true and which is taken if the conditional is
5824 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5827 extract_true_false_edges_from_block (basic_block b,
5831 edge e = EDGE_SUCC (b, 0);
5833 if (e->flags & EDGE_TRUE_VALUE)
5836 *false_edge = EDGE_SUCC (b, 1);
5841 *true_edge = EDGE_SUCC (b, 1);
5845 struct tree_opt_pass pass_warn_function_return =
5849 execute_warn_function_return, /* execute */
5852 0, /* static_pass_number */
5854 PROP_cfg, /* properties_required */
5855 0, /* properties_provided */
5856 0, /* properties_destroyed */
5857 0, /* todo_flags_start */
5858 0, /* todo_flags_finish */
5862 /* Emit noreturn warnings. */
5865 execute_warn_function_noreturn (void)
5867 if (warn_missing_noreturn
5868 && !TREE_THIS_VOLATILE (cfun->decl)
5869 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5870 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5871 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5872 "for attribute %<noreturn%>",
5877 struct tree_opt_pass pass_warn_function_noreturn =
5881 execute_warn_function_noreturn, /* execute */
5884 0, /* static_pass_number */
5886 PROP_cfg, /* properties_required */
5887 0, /* properties_provided */
5888 0, /* properties_destroyed */
5889 0, /* todo_flags_start */
5890 0, /* todo_flags_finish */