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));
621 /* Called for each element in the hash table (P) as we delete the
622 edge to cases hash table.
624 Clear all the TREE_CHAINs to prevent problems with copying of
625 SWITCH_EXPRs and structure sharing rules, then free the hash table
629 edge_to_cases_cleanup (void *key ATTRIBUTE_UNUSED, void **value,
630 void *data ATTRIBUTE_UNUSED)
634 for (t = (tree) *value; t; t = next)
636 next = TREE_CHAIN (t);
637 TREE_CHAIN (t) = NULL;
644 /* Start recording information mapping edges to case labels. */
647 start_recording_case_labels (void)
649 gcc_assert (edge_to_cases == NULL);
650 edge_to_cases = pointer_map_create ();
653 /* Return nonzero if we are recording information for case labels. */
656 recording_case_labels_p (void)
658 return (edge_to_cases != NULL);
661 /* Stop recording information mapping edges to case labels and
662 remove any information we have recorded. */
664 end_recording_case_labels (void)
666 pointer_map_traverse (edge_to_cases, edge_to_cases_cleanup, NULL);
667 pointer_map_destroy (edge_to_cases);
668 edge_to_cases = NULL;
671 /* If we are inside a {start,end}_recording_cases block, then return
672 a chain of CASE_LABEL_EXPRs from T which reference E.
674 Otherwise return NULL. */
677 get_cases_for_edge (edge e, tree t)
683 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
684 chains available. Return NULL so the caller can detect this case. */
685 if (!recording_case_labels_p ())
688 slot = pointer_map_contains (edge_to_cases, e);
692 /* If we did not find E in the hash table, then this must be the first
693 time we have been queried for information about E & T. Add all the
694 elements from T to the hash table then perform the query again. */
696 vec = SWITCH_LABELS (t);
697 n = TREE_VEC_LENGTH (vec);
698 for (i = 0; i < n; i++)
700 tree elt = TREE_VEC_ELT (vec, i);
701 tree lab = CASE_LABEL (elt);
702 basic_block label_bb = label_to_block (lab);
703 edge this_edge = find_edge (e->src, label_bb);
705 /* Add it to the chain of CASE_LABEL_EXPRs referencing E, or create
707 slot = pointer_map_insert (edge_to_cases, this_edge);
708 TREE_CHAIN (elt) = (tree) *slot;
712 return (tree) *pointer_map_contains (edge_to_cases, e);
715 /* Create the edges for a SWITCH_EXPR starting at block BB.
716 At this point, the switch body has been lowered and the
717 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
720 make_switch_expr_edges (basic_block bb)
722 tree entry = last_stmt (bb);
726 vec = SWITCH_LABELS (entry);
727 n = TREE_VEC_LENGTH (vec);
729 for (i = 0; i < n; ++i)
731 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
732 basic_block label_bb = label_to_block (lab);
733 make_edge (bb, label_bb, 0);
738 /* Return the basic block holding label DEST. */
741 label_to_block_fn (struct function *ifun, tree dest)
743 int uid = LABEL_DECL_UID (dest);
745 /* We would die hard when faced by an undefined label. Emit a label to
746 the very first basic block. This will hopefully make even the dataflow
747 and undefined variable warnings quite right. */
748 if ((errorcount || sorrycount) && uid < 0)
750 block_stmt_iterator bsi =
751 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
754 stmt = build1 (LABEL_EXPR, void_type_node, dest);
755 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
756 uid = LABEL_DECL_UID (dest);
758 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
759 <= (unsigned int) uid)
761 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
764 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
765 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
768 make_abnormal_goto_edges (basic_block bb, bool for_call)
770 basic_block target_bb;
771 block_stmt_iterator bsi;
773 FOR_EACH_BB (target_bb)
774 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
776 tree target = bsi_stmt (bsi);
778 if (TREE_CODE (target) != LABEL_EXPR)
781 target = LABEL_EXPR_LABEL (target);
783 /* Make an edge to every label block that has been marked as a
784 potential target for a computed goto or a non-local goto. */
785 if ((FORCED_LABEL (target) && !for_call)
786 || (DECL_NONLOCAL (target) && for_call))
788 make_edge (bb, target_bb, EDGE_ABNORMAL);
794 /* Create edges for a goto statement at block BB. */
797 make_goto_expr_edges (basic_block bb)
799 block_stmt_iterator last = bsi_last (bb);
800 tree goto_t = bsi_stmt (last);
802 /* A simple GOTO creates normal edges. */
803 if (simple_goto_p (goto_t))
805 tree dest = GOTO_DESTINATION (goto_t);
806 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
807 #ifdef USE_MAPPED_LOCATION
808 e->goto_locus = EXPR_LOCATION (goto_t);
810 e->goto_locus = EXPR_LOCUS (goto_t);
812 bsi_remove (&last, true);
816 /* A computed GOTO creates abnormal edges. */
817 make_abnormal_goto_edges (bb, false);
821 /*---------------------------------------------------------------------------
823 ---------------------------------------------------------------------------*/
825 /* Cleanup useless labels in basic blocks. This is something we wish
826 to do early because it allows us to group case labels before creating
827 the edges for the CFG, and it speeds up block statement iterators in
829 We only run this pass once, running it more than once is probably not
832 /* A map from basic block index to the leading label of that block. */
833 static tree *label_for_bb;
835 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
837 update_eh_label (struct eh_region *region)
839 tree old_label = get_eh_region_tree_label (region);
843 basic_block bb = label_to_block (old_label);
845 /* ??? After optimizing, there may be EH regions with labels
846 that have already been removed from the function body, so
847 there is no basic block for them. */
851 new_label = label_for_bb[bb->index];
852 set_eh_region_tree_label (region, new_label);
856 /* Given LABEL return the first label in the same basic block. */
858 main_block_label (tree label)
860 basic_block bb = label_to_block (label);
862 /* label_to_block possibly inserted undefined label into the chain. */
863 if (!label_for_bb[bb->index])
864 label_for_bb[bb->index] = label;
865 return label_for_bb[bb->index];
868 /* Cleanup redundant labels. This is a three-step process:
869 1) Find the leading label for each block.
870 2) Redirect all references to labels to the leading labels.
871 3) Cleanup all useless labels. */
874 cleanup_dead_labels (void)
877 label_for_bb = XCNEWVEC (tree, last_basic_block);
879 /* Find a suitable label for each block. We use the first user-defined
880 label if there is one, or otherwise just the first label we see. */
883 block_stmt_iterator i;
885 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
887 tree label, stmt = bsi_stmt (i);
889 if (TREE_CODE (stmt) != LABEL_EXPR)
892 label = LABEL_EXPR_LABEL (stmt);
894 /* If we have not yet seen a label for the current block,
895 remember this one and see if there are more labels. */
896 if (! label_for_bb[bb->index])
898 label_for_bb[bb->index] = label;
902 /* If we did see a label for the current block already, but it
903 is an artificially created label, replace it if the current
904 label is a user defined label. */
905 if (! DECL_ARTIFICIAL (label)
906 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
908 label_for_bb[bb->index] = label;
914 /* Now redirect all jumps/branches to the selected label.
915 First do so for each block ending in a control statement. */
918 tree stmt = last_stmt (bb);
922 switch (TREE_CODE (stmt))
926 tree true_branch, false_branch;
928 true_branch = COND_EXPR_THEN (stmt);
929 false_branch = COND_EXPR_ELSE (stmt);
931 GOTO_DESTINATION (true_branch)
932 = main_block_label (GOTO_DESTINATION (true_branch));
933 GOTO_DESTINATION (false_branch)
934 = main_block_label (GOTO_DESTINATION (false_branch));
942 tree vec = SWITCH_LABELS (stmt);
943 size_t n = TREE_VEC_LENGTH (vec);
945 /* Replace all destination labels. */
946 for (i = 0; i < n; ++i)
948 tree elt = TREE_VEC_ELT (vec, i);
949 tree label = main_block_label (CASE_LABEL (elt));
950 CASE_LABEL (elt) = label;
955 /* We have to handle GOTO_EXPRs until they're removed, and we don't
956 remove them until after we've created the CFG edges. */
958 if (! computed_goto_p (stmt))
960 GOTO_DESTINATION (stmt)
961 = main_block_label (GOTO_DESTINATION (stmt));
970 for_each_eh_region (update_eh_label);
972 /* Finally, purge dead labels. All user-defined labels and labels that
973 can be the target of non-local gotos and labels which have their
974 address taken are preserved. */
977 block_stmt_iterator i;
978 tree label_for_this_bb = label_for_bb[bb->index];
980 if (! label_for_this_bb)
983 for (i = bsi_start (bb); !bsi_end_p (i); )
985 tree label, stmt = bsi_stmt (i);
987 if (TREE_CODE (stmt) != LABEL_EXPR)
990 label = LABEL_EXPR_LABEL (stmt);
992 if (label == label_for_this_bb
993 || ! DECL_ARTIFICIAL (label)
994 || DECL_NONLOCAL (label)
995 || FORCED_LABEL (label))
998 bsi_remove (&i, true);
1002 free (label_for_bb);
1005 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1006 and scan the sorted vector of cases. Combine the ones jumping to the
1008 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1011 group_case_labels (void)
1017 tree stmt = last_stmt (bb);
1018 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1020 tree labels = SWITCH_LABELS (stmt);
1021 int old_size = TREE_VEC_LENGTH (labels);
1022 int i, j, new_size = old_size;
1023 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1026 /* The default label is always the last case in a switch
1027 statement after gimplification. */
1028 default_label = CASE_LABEL (default_case);
1030 /* Look for possible opportunities to merge cases.
1031 Ignore the last element of the label vector because it
1032 must be the default case. */
1034 while (i < old_size - 1)
1036 tree base_case, base_label, base_high;
1037 base_case = TREE_VEC_ELT (labels, i);
1039 gcc_assert (base_case);
1040 base_label = CASE_LABEL (base_case);
1042 /* Discard cases that have the same destination as the
1044 if (base_label == default_label)
1046 TREE_VEC_ELT (labels, i) = NULL_TREE;
1052 base_high = CASE_HIGH (base_case) ?
1053 CASE_HIGH (base_case) : CASE_LOW (base_case);
1055 /* Try to merge case labels. Break out when we reach the end
1056 of the label vector or when we cannot merge the next case
1057 label with the current one. */
1058 while (i < old_size - 1)
1060 tree merge_case = TREE_VEC_ELT (labels, i);
1061 tree merge_label = CASE_LABEL (merge_case);
1062 tree t = int_const_binop (PLUS_EXPR, base_high,
1063 integer_one_node, 1);
1065 /* Merge the cases if they jump to the same place,
1066 and their ranges are consecutive. */
1067 if (merge_label == base_label
1068 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1070 base_high = CASE_HIGH (merge_case) ?
1071 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1072 CASE_HIGH (base_case) = base_high;
1073 TREE_VEC_ELT (labels, i) = NULL_TREE;
1082 /* Compress the case labels in the label vector, and adjust the
1083 length of the vector. */
1084 for (i = 0, j = 0; i < new_size; i++)
1086 while (! TREE_VEC_ELT (labels, j))
1088 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1090 TREE_VEC_LENGTH (labels) = new_size;
1095 /* Checks whether we can merge block B into block A. */
1098 tree_can_merge_blocks_p (basic_block a, basic_block b)
1101 block_stmt_iterator bsi;
1104 if (!single_succ_p (a))
1107 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1110 if (single_succ (a) != b)
1113 if (!single_pred_p (b))
1116 if (b == EXIT_BLOCK_PTR)
1119 /* If A ends by a statement causing exceptions or something similar, we
1120 cannot merge the blocks. */
1121 stmt = last_stmt (a);
1122 if (stmt && stmt_ends_bb_p (stmt))
1125 /* Do not allow a block with only a non-local label to be merged. */
1126 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1127 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1130 /* It must be possible to eliminate all phi nodes in B. If ssa form
1131 is not up-to-date, we cannot eliminate any phis; however, if only
1132 some symbols as whole are marked for renaming, this is not a problem,
1133 as phi nodes for those symbols are irrelevant in updating anyway. */
1134 phi = phi_nodes (b);
1137 if (name_mappings_registered_p ())
1140 for (; phi; phi = PHI_CHAIN (phi))
1141 if (!is_gimple_reg (PHI_RESULT (phi))
1142 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1146 /* Do not remove user labels. */
1147 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1149 stmt = bsi_stmt (bsi);
1150 if (TREE_CODE (stmt) != LABEL_EXPR)
1152 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1156 /* Protect the loop latches. */
1158 && b->loop_father->latch == b)
1164 /* Replaces all uses of NAME by VAL. */
1167 replace_uses_by (tree name, tree val)
1169 imm_use_iterator imm_iter;
1174 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1176 if (TREE_CODE (stmt) != PHI_NODE)
1177 push_stmt_changes (&stmt);
1179 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1181 replace_exp (use, val);
1183 if (TREE_CODE (stmt) == PHI_NODE)
1185 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1186 if (e->flags & EDGE_ABNORMAL)
1188 /* This can only occur for virtual operands, since
1189 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1190 would prevent replacement. */
1191 gcc_assert (!is_gimple_reg (name));
1192 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1197 if (TREE_CODE (stmt) != PHI_NODE)
1201 fold_stmt_inplace (stmt);
1202 if (cfgcleanup_altered_bbs)
1203 bitmap_set_bit (cfgcleanup_altered_bbs, bb_for_stmt (stmt)->index);
1205 /* FIXME. This should go in pop_stmt_changes. */
1206 rhs = get_rhs (stmt);
1207 if (TREE_CODE (rhs) == ADDR_EXPR)
1208 recompute_tree_invariant_for_addr_expr (rhs);
1210 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1212 pop_stmt_changes (&stmt);
1216 gcc_assert (has_zero_uses (name));
1218 /* Also update the trees stored in loop structures. */
1224 FOR_EACH_LOOP (li, loop, 0)
1226 substitute_in_loop_info (loop, name, val);
1231 /* Merge block B into block A. */
1234 tree_merge_blocks (basic_block a, basic_block b)
1236 block_stmt_iterator bsi;
1237 tree_stmt_iterator last;
1241 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1243 /* Remove all single-valued PHI nodes from block B of the form
1244 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1246 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1248 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1250 bool may_replace_uses = may_propagate_copy (def, use);
1252 /* In case we have loops to care about, do not propagate arguments of
1253 loop closed ssa phi nodes. */
1255 && is_gimple_reg (def)
1256 && TREE_CODE (use) == SSA_NAME
1257 && a->loop_father != b->loop_father)
1258 may_replace_uses = false;
1260 if (!may_replace_uses)
1262 gcc_assert (is_gimple_reg (def));
1264 /* Note that just emitting the copies is fine -- there is no problem
1265 with ordering of phi nodes. This is because A is the single
1266 predecessor of B, therefore results of the phi nodes cannot
1267 appear as arguments of the phi nodes. */
1268 copy = build_gimple_modify_stmt (def, use);
1269 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1270 SSA_NAME_DEF_STMT (def) = copy;
1271 remove_phi_node (phi, NULL, false);
1275 replace_uses_by (def, use);
1276 remove_phi_node (phi, NULL, true);
1280 /* Ensure that B follows A. */
1281 move_block_after (b, a);
1283 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1284 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1286 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1287 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1289 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1291 tree label = bsi_stmt (bsi);
1293 bsi_remove (&bsi, false);
1294 /* Now that we can thread computed gotos, we might have
1295 a situation where we have a forced label in block B
1296 However, the label at the start of block B might still be
1297 used in other ways (think about the runtime checking for
1298 Fortran assigned gotos). So we can not just delete the
1299 label. Instead we move the label to the start of block A. */
1300 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1302 block_stmt_iterator dest_bsi = bsi_start (a);
1303 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1308 change_bb_for_stmt (bsi_stmt (bsi), a);
1313 /* Merge the chains. */
1314 last = tsi_last (bb_stmt_list (a));
1315 tsi_link_after (&last, bb_stmt_list (b), TSI_NEW_STMT);
1316 set_bb_stmt_list (b, NULL_TREE);
1318 if (cfgcleanup_altered_bbs)
1319 bitmap_set_bit (cfgcleanup_altered_bbs, a->index);
1323 /* Return the one of two successors of BB that is not reachable by a
1324 reached by a complex edge, if there is one. Else, return BB. We use
1325 this in optimizations that use post-dominators for their heuristics,
1326 to catch the cases in C++ where function calls are involved. */
1329 single_noncomplex_succ (basic_block bb)
1332 if (EDGE_COUNT (bb->succs) != 2)
1335 e0 = EDGE_SUCC (bb, 0);
1336 e1 = EDGE_SUCC (bb, 1);
1337 if (e0->flags & EDGE_COMPLEX)
1339 if (e1->flags & EDGE_COMPLEX)
1346 /* Walk the function tree removing unnecessary statements.
1348 * Empty statement nodes are removed
1350 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1352 * Unnecessary COND_EXPRs are removed
1354 * Some unnecessary BIND_EXPRs are removed
1356 Clearly more work could be done. The trick is doing the analysis
1357 and removal fast enough to be a net improvement in compile times.
1359 Note that when we remove a control structure such as a COND_EXPR
1360 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1361 to ensure we eliminate all the useless code. */
1372 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1375 remove_useless_stmts_warn_notreached (tree stmt)
1377 if (EXPR_HAS_LOCATION (stmt))
1379 location_t loc = EXPR_LOCATION (stmt);
1380 if (LOCATION_LINE (loc) > 0)
1382 warning (0, "%Hwill never be executed", &loc);
1387 switch (TREE_CODE (stmt))
1389 case STATEMENT_LIST:
1391 tree_stmt_iterator i;
1392 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1393 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1399 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1401 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1403 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1407 case TRY_FINALLY_EXPR:
1408 case TRY_CATCH_EXPR:
1409 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1411 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1416 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1417 case EH_FILTER_EXPR:
1418 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1420 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1423 /* Not a live container. */
1431 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1433 tree then_clause, else_clause, cond;
1434 bool save_has_label, then_has_label, else_has_label;
1436 save_has_label = data->has_label;
1437 data->has_label = false;
1438 data->last_goto = NULL;
1440 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1442 then_has_label = data->has_label;
1443 data->has_label = false;
1444 data->last_goto = NULL;
1446 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1448 else_has_label = data->has_label;
1449 data->has_label = save_has_label | then_has_label | else_has_label;
1451 then_clause = COND_EXPR_THEN (*stmt_p);
1452 else_clause = COND_EXPR_ELSE (*stmt_p);
1453 cond = fold (COND_EXPR_COND (*stmt_p));
1455 /* If neither arm does anything at all, we can remove the whole IF. */
1456 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1458 *stmt_p = build_empty_stmt ();
1459 data->repeat = true;
1462 /* If there are no reachable statements in an arm, then we can
1463 zap the entire conditional. */
1464 else if (integer_nonzerop (cond) && !else_has_label)
1466 if (warn_notreached)
1467 remove_useless_stmts_warn_notreached (else_clause);
1468 *stmt_p = then_clause;
1469 data->repeat = true;
1471 else if (integer_zerop (cond) && !then_has_label)
1473 if (warn_notreached)
1474 remove_useless_stmts_warn_notreached (then_clause);
1475 *stmt_p = else_clause;
1476 data->repeat = true;
1479 /* Check a couple of simple things on then/else with single stmts. */
1482 tree then_stmt = expr_only (then_clause);
1483 tree else_stmt = expr_only (else_clause);
1485 /* Notice branches to a common destination. */
1486 if (then_stmt && else_stmt
1487 && TREE_CODE (then_stmt) == GOTO_EXPR
1488 && TREE_CODE (else_stmt) == GOTO_EXPR
1489 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1491 *stmt_p = then_stmt;
1492 data->repeat = true;
1495 /* If the THEN/ELSE clause merely assigns a value to a variable or
1496 parameter which is already known to contain that value, then
1497 remove the useless THEN/ELSE clause. */
1498 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1501 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1502 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1503 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1504 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1506 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1507 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1508 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1509 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1511 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1512 ? then_stmt : else_stmt);
1513 tree *location = (TREE_CODE (cond) == EQ_EXPR
1514 ? &COND_EXPR_THEN (*stmt_p)
1515 : &COND_EXPR_ELSE (*stmt_p));
1518 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1519 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1520 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1521 *location = alloc_stmt_list ();
1525 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1526 would be re-introduced during lowering. */
1527 data->last_goto = NULL;
1532 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1534 bool save_may_branch, save_may_throw;
1535 bool this_may_branch, this_may_throw;
1537 /* Collect may_branch and may_throw information for the body only. */
1538 save_may_branch = data->may_branch;
1539 save_may_throw = data->may_throw;
1540 data->may_branch = false;
1541 data->may_throw = false;
1542 data->last_goto = NULL;
1544 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1546 this_may_branch = data->may_branch;
1547 this_may_throw = data->may_throw;
1548 data->may_branch |= save_may_branch;
1549 data->may_throw |= save_may_throw;
1550 data->last_goto = NULL;
1552 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1554 /* If the body is empty, then we can emit the FINALLY block without
1555 the enclosing TRY_FINALLY_EXPR. */
1556 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1558 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1559 data->repeat = true;
1562 /* If the handler is empty, then we can emit the TRY block without
1563 the enclosing TRY_FINALLY_EXPR. */
1564 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1566 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1567 data->repeat = true;
1570 /* If the body neither throws, nor branches, then we can safely
1571 string the TRY and FINALLY blocks together. */
1572 else if (!this_may_branch && !this_may_throw)
1574 tree stmt = *stmt_p;
1575 *stmt_p = TREE_OPERAND (stmt, 0);
1576 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1577 data->repeat = true;
1583 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1585 bool save_may_throw, this_may_throw;
1586 tree_stmt_iterator i;
1589 /* Collect may_throw information for the body only. */
1590 save_may_throw = data->may_throw;
1591 data->may_throw = false;
1592 data->last_goto = NULL;
1594 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1596 this_may_throw = data->may_throw;
1597 data->may_throw = save_may_throw;
1599 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1600 if (!this_may_throw)
1602 if (warn_notreached)
1603 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1604 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1605 data->repeat = true;
1609 /* Process the catch clause specially. We may be able to tell that
1610 no exceptions propagate past this point. */
1612 this_may_throw = true;
1613 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1614 stmt = tsi_stmt (i);
1615 data->last_goto = NULL;
1617 switch (TREE_CODE (stmt))
1620 for (; !tsi_end_p (i); tsi_next (&i))
1622 stmt = tsi_stmt (i);
1623 /* If we catch all exceptions, then the body does not
1624 propagate exceptions past this point. */
1625 if (CATCH_TYPES (stmt) == NULL)
1626 this_may_throw = false;
1627 data->last_goto = NULL;
1628 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1632 case EH_FILTER_EXPR:
1633 if (EH_FILTER_MUST_NOT_THROW (stmt))
1634 this_may_throw = false;
1635 else if (EH_FILTER_TYPES (stmt) == NULL)
1636 this_may_throw = false;
1637 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1641 /* Otherwise this is a cleanup. */
1642 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1644 /* If the cleanup is empty, then we can emit the TRY block without
1645 the enclosing TRY_CATCH_EXPR. */
1646 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1648 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1649 data->repeat = true;
1653 data->may_throw |= this_may_throw;
1658 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1662 /* First remove anything underneath the BIND_EXPR. */
1663 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1665 /* If the BIND_EXPR has no variables, then we can pull everything
1666 up one level and remove the BIND_EXPR, unless this is the toplevel
1667 BIND_EXPR for the current function or an inlined function.
1669 When this situation occurs we will want to apply this
1670 optimization again. */
1671 block = BIND_EXPR_BLOCK (*stmt_p);
1672 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1673 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1675 || ! BLOCK_ABSTRACT_ORIGIN (block)
1676 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1679 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1680 data->repeat = true;
1686 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1688 tree dest = GOTO_DESTINATION (*stmt_p);
1690 data->may_branch = true;
1691 data->last_goto = NULL;
1693 /* Record the last goto expr, so that we can delete it if unnecessary. */
1694 if (TREE_CODE (dest) == LABEL_DECL)
1695 data->last_goto = stmt_p;
1700 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1702 tree label = LABEL_EXPR_LABEL (*stmt_p);
1704 data->has_label = true;
1706 /* We do want to jump across non-local label receiver code. */
1707 if (DECL_NONLOCAL (label))
1708 data->last_goto = NULL;
1710 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1712 *data->last_goto = build_empty_stmt ();
1713 data->repeat = true;
1716 /* ??? Add something here to delete unused labels. */
1720 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1721 decl. This allows us to eliminate redundant or useless
1722 calls to "const" functions.
1724 Gimplifier already does the same operation, but we may notice functions
1725 being const and pure once their calls has been gimplified, so we need
1726 to update the flag. */
1729 update_call_expr_flags (tree call)
1731 tree decl = get_callee_fndecl (call);
1734 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1735 TREE_SIDE_EFFECTS (call) = 0;
1736 if (TREE_NOTHROW (decl))
1737 TREE_NOTHROW (call) = 1;
1741 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1744 notice_special_calls (tree t)
1746 int flags = call_expr_flags (t);
1748 if (flags & ECF_MAY_BE_ALLOCA)
1749 current_function_calls_alloca = true;
1750 if (flags & ECF_RETURNS_TWICE)
1751 current_function_calls_setjmp = true;
1755 /* Clear flags set by notice_special_calls. Used by dead code removal
1756 to update the flags. */
1759 clear_special_calls (void)
1761 current_function_calls_alloca = false;
1762 current_function_calls_setjmp = false;
1767 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1771 switch (TREE_CODE (t))
1774 remove_useless_stmts_cond (tp, data);
1777 case TRY_FINALLY_EXPR:
1778 remove_useless_stmts_tf (tp, data);
1781 case TRY_CATCH_EXPR:
1782 remove_useless_stmts_tc (tp, data);
1786 remove_useless_stmts_bind (tp, data);
1790 remove_useless_stmts_goto (tp, data);
1794 remove_useless_stmts_label (tp, data);
1799 data->last_goto = NULL;
1800 data->may_branch = true;
1805 data->last_goto = NULL;
1806 notice_special_calls (t);
1807 update_call_expr_flags (t);
1808 if (tree_could_throw_p (t))
1809 data->may_throw = true;
1815 case GIMPLE_MODIFY_STMT:
1816 data->last_goto = NULL;
1818 op = get_call_expr_in (t);
1821 update_call_expr_flags (op);
1822 notice_special_calls (op);
1824 if (tree_could_throw_p (t))
1825 data->may_throw = true;
1828 case STATEMENT_LIST:
1830 tree_stmt_iterator i = tsi_start (t);
1831 while (!tsi_end_p (i))
1834 if (IS_EMPTY_STMT (t))
1840 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1843 if (TREE_CODE (t) == STATEMENT_LIST)
1845 tsi_link_before (&i, t, TSI_SAME_STMT);
1855 data->last_goto = NULL;
1859 data->last_goto = NULL;
1865 remove_useless_stmts (void)
1867 struct rus_data data;
1869 clear_special_calls ();
1873 memset (&data, 0, sizeof (data));
1874 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1876 while (data.repeat);
1881 struct tree_opt_pass pass_remove_useless_stmts =
1883 "useless", /* name */
1885 remove_useless_stmts, /* execute */
1888 0, /* static_pass_number */
1890 PROP_gimple_any, /* properties_required */
1891 0, /* properties_provided */
1892 0, /* properties_destroyed */
1893 0, /* todo_flags_start */
1894 TODO_dump_func, /* todo_flags_finish */
1898 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1901 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1905 /* Since this block is no longer reachable, we can just delete all
1906 of its PHI nodes. */
1907 phi = phi_nodes (bb);
1910 tree next = PHI_CHAIN (phi);
1911 remove_phi_node (phi, NULL_TREE, true);
1915 /* Remove edges to BB's successors. */
1916 while (EDGE_COUNT (bb->succs) > 0)
1917 remove_edge (EDGE_SUCC (bb, 0));
1921 /* Remove statements of basic block BB. */
1924 remove_bb (basic_block bb)
1926 block_stmt_iterator i;
1927 #ifdef USE_MAPPED_LOCATION
1928 source_location loc = UNKNOWN_LOCATION;
1930 source_locus loc = 0;
1935 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1936 if (dump_flags & TDF_DETAILS)
1938 dump_bb (bb, dump_file, 0);
1939 fprintf (dump_file, "\n");
1945 struct loop *loop = bb->loop_father;
1947 /* If a loop gets removed, clean up the information associated
1949 if (loop->latch == bb
1950 || loop->header == bb)
1951 free_numbers_of_iterations_estimates_loop (loop);
1954 /* Remove all the instructions in the block. */
1955 if (bb_stmt_list (bb) != NULL_TREE)
1957 for (i = bsi_start (bb); !bsi_end_p (i);)
1959 tree stmt = bsi_stmt (i);
1960 if (TREE_CODE (stmt) == LABEL_EXPR
1961 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
1962 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
1965 block_stmt_iterator new_bsi;
1967 /* A non-reachable non-local label may still be referenced.
1968 But it no longer needs to carry the extra semantics of
1970 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1972 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
1973 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
1976 new_bb = bb->prev_bb;
1977 new_bsi = bsi_start (new_bb);
1978 bsi_remove (&i, false);
1979 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
1983 /* Release SSA definitions if we are in SSA. Note that we
1984 may be called when not in SSA. For example,
1985 final_cleanup calls this function via
1986 cleanup_tree_cfg. */
1987 if (gimple_in_ssa_p (cfun))
1988 release_defs (stmt);
1990 bsi_remove (&i, true);
1993 /* Don't warn for removed gotos. Gotos are often removed due to
1994 jump threading, thus resulting in bogus warnings. Not great,
1995 since this way we lose warnings for gotos in the original
1996 program that are indeed unreachable. */
1997 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
1999 #ifdef USE_MAPPED_LOCATION
2000 if (EXPR_HAS_LOCATION (stmt))
2001 loc = EXPR_LOCATION (stmt);
2004 t = EXPR_LOCUS (stmt);
2005 if (t && LOCATION_LINE (*t) > 0)
2012 /* If requested, give a warning that the first statement in the
2013 block is unreachable. We walk statements backwards in the
2014 loop above, so the last statement we process is the first statement
2016 #ifdef USE_MAPPED_LOCATION
2017 if (loc > BUILTINS_LOCATION)
2018 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2021 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2024 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2029 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2030 predicate VAL, return the edge that will be taken out of the block.
2031 If VAL does not match a unique edge, NULL is returned. */
2034 find_taken_edge (basic_block bb, tree val)
2038 stmt = last_stmt (bb);
2041 gcc_assert (is_ctrl_stmt (stmt));
2044 if (! is_gimple_min_invariant (val))
2047 if (TREE_CODE (stmt) == COND_EXPR)
2048 return find_taken_edge_cond_expr (bb, val);
2050 if (TREE_CODE (stmt) == SWITCH_EXPR)
2051 return find_taken_edge_switch_expr (bb, val);
2053 if (computed_goto_p (stmt))
2055 /* Only optimize if the argument is a label, if the argument is
2056 not a label then we can not construct a proper CFG.
2058 It may be the case that we only need to allow the LABEL_REF to
2059 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2060 appear inside a LABEL_EXPR just to be safe. */
2061 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2062 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2063 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2070 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2071 statement, determine which of the outgoing edges will be taken out of the
2072 block. Return NULL if either edge may be taken. */
2075 find_taken_edge_computed_goto (basic_block bb, tree val)
2080 dest = label_to_block (val);
2083 e = find_edge (bb, dest);
2084 gcc_assert (e != NULL);
2090 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2091 statement, determine which of the two edges will be taken out of the
2092 block. Return NULL if either edge may be taken. */
2095 find_taken_edge_cond_expr (basic_block bb, tree val)
2097 edge true_edge, false_edge;
2099 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2101 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2102 return (integer_zerop (val) ? false_edge : true_edge);
2105 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2106 statement, determine which edge will be taken out of the block. Return
2107 NULL if any edge may be taken. */
2110 find_taken_edge_switch_expr (basic_block bb, tree val)
2112 tree switch_expr, taken_case;
2113 basic_block dest_bb;
2116 switch_expr = last_stmt (bb);
2117 taken_case = find_case_label_for_value (switch_expr, val);
2118 dest_bb = label_to_block (CASE_LABEL (taken_case));
2120 e = find_edge (bb, dest_bb);
2126 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2127 We can make optimal use here of the fact that the case labels are
2128 sorted: We can do a binary search for a case matching VAL. */
2131 find_case_label_for_value (tree switch_expr, tree val)
2133 tree vec = SWITCH_LABELS (switch_expr);
2134 size_t low, high, n = TREE_VEC_LENGTH (vec);
2135 tree default_case = TREE_VEC_ELT (vec, n - 1);
2137 for (low = -1, high = n - 1; high - low > 1; )
2139 size_t i = (high + low) / 2;
2140 tree t = TREE_VEC_ELT (vec, i);
2143 /* Cache the result of comparing CASE_LOW and val. */
2144 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2151 if (CASE_HIGH (t) == NULL)
2153 /* A singe-valued case label. */
2159 /* A case range. We can only handle integer ranges. */
2160 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2165 return default_case;
2171 /*---------------------------------------------------------------------------
2173 ---------------------------------------------------------------------------*/
2175 /* Dump tree-specific information of block BB to file OUTF. */
2178 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2180 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2184 /* Dump a basic block on stderr. */
2187 debug_tree_bb (basic_block bb)
2189 dump_bb (bb, stderr, 0);
2193 /* Dump basic block with index N on stderr. */
2196 debug_tree_bb_n (int n)
2198 debug_tree_bb (BASIC_BLOCK (n));
2199 return BASIC_BLOCK (n);
2203 /* Dump the CFG on stderr.
2205 FLAGS are the same used by the tree dumping functions
2206 (see TDF_* in tree-pass.h). */
2209 debug_tree_cfg (int flags)
2211 dump_tree_cfg (stderr, flags);
2215 /* Dump the program showing basic block boundaries on the given FILE.
2217 FLAGS are the same used by the tree dumping functions (see TDF_* in
2221 dump_tree_cfg (FILE *file, int flags)
2223 if (flags & TDF_DETAILS)
2225 const char *funcname
2226 = lang_hooks.decl_printable_name (current_function_decl, 2);
2229 fprintf (file, ";; Function %s\n\n", funcname);
2230 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2231 n_basic_blocks, n_edges, last_basic_block);
2233 brief_dump_cfg (file);
2234 fprintf (file, "\n");
2237 if (flags & TDF_STATS)
2238 dump_cfg_stats (file);
2240 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2244 /* Dump CFG statistics on FILE. */
2247 dump_cfg_stats (FILE *file)
2249 static long max_num_merged_labels = 0;
2250 unsigned long size, total = 0;
2253 const char * const fmt_str = "%-30s%-13s%12s\n";
2254 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2255 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2256 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2257 const char *funcname
2258 = lang_hooks.decl_printable_name (current_function_decl, 2);
2261 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2263 fprintf (file, "---------------------------------------------------------\n");
2264 fprintf (file, fmt_str, "", " Number of ", "Memory");
2265 fprintf (file, fmt_str, "", " instances ", "used ");
2266 fprintf (file, "---------------------------------------------------------\n");
2268 size = n_basic_blocks * sizeof (struct basic_block_def);
2270 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2271 SCALE (size), LABEL (size));
2275 num_edges += EDGE_COUNT (bb->succs);
2276 size = num_edges * sizeof (struct edge_def);
2278 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2280 fprintf (file, "---------------------------------------------------------\n");
2281 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2283 fprintf (file, "---------------------------------------------------------\n");
2284 fprintf (file, "\n");
2286 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2287 max_num_merged_labels = cfg_stats.num_merged_labels;
2289 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2290 cfg_stats.num_merged_labels, max_num_merged_labels);
2292 fprintf (file, "\n");
2296 /* Dump CFG statistics on stderr. Keep extern so that it's always
2297 linked in the final executable. */
2300 debug_cfg_stats (void)
2302 dump_cfg_stats (stderr);
2306 /* Dump the flowgraph to a .vcg FILE. */
2309 tree_cfg2vcg (FILE *file)
2314 const char *funcname
2315 = lang_hooks.decl_printable_name (current_function_decl, 2);
2317 /* Write the file header. */
2318 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2319 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2320 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2322 /* Write blocks and edges. */
2323 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2325 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2328 if (e->flags & EDGE_FAKE)
2329 fprintf (file, " linestyle: dotted priority: 10");
2331 fprintf (file, " linestyle: solid priority: 100");
2333 fprintf (file, " }\n");
2339 enum tree_code head_code, end_code;
2340 const char *head_name, *end_name;
2343 tree first = first_stmt (bb);
2344 tree last = last_stmt (bb);
2348 head_code = TREE_CODE (first);
2349 head_name = tree_code_name[head_code];
2350 head_line = get_lineno (first);
2353 head_name = "no-statement";
2357 end_code = TREE_CODE (last);
2358 end_name = tree_code_name[end_code];
2359 end_line = get_lineno (last);
2362 end_name = "no-statement";
2364 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2365 bb->index, bb->index, head_name, head_line, end_name,
2368 FOR_EACH_EDGE (e, ei, bb->succs)
2370 if (e->dest == EXIT_BLOCK_PTR)
2371 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2373 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2375 if (e->flags & EDGE_FAKE)
2376 fprintf (file, " priority: 10 linestyle: dotted");
2378 fprintf (file, " priority: 100 linestyle: solid");
2380 fprintf (file, " }\n");
2383 if (bb->next_bb != EXIT_BLOCK_PTR)
2387 fputs ("}\n\n", file);
2392 /*---------------------------------------------------------------------------
2393 Miscellaneous helpers
2394 ---------------------------------------------------------------------------*/
2396 /* Return true if T represents a stmt that always transfers control. */
2399 is_ctrl_stmt (tree t)
2401 return (TREE_CODE (t) == COND_EXPR
2402 || TREE_CODE (t) == SWITCH_EXPR
2403 || TREE_CODE (t) == GOTO_EXPR
2404 || TREE_CODE (t) == RETURN_EXPR
2405 || TREE_CODE (t) == RESX_EXPR);
2409 /* Return true if T is a statement that may alter the flow of control
2410 (e.g., a call to a non-returning function). */
2413 is_ctrl_altering_stmt (tree t)
2418 call = get_call_expr_in (t);
2421 /* A non-pure/const CALL_EXPR alters flow control if the current
2422 function has nonlocal labels. */
2423 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2426 /* A CALL_EXPR also alters control flow if it does not return. */
2427 if (call_expr_flags (call) & ECF_NORETURN)
2431 /* OpenMP directives alter control flow. */
2432 if (OMP_DIRECTIVE_P (t))
2435 /* If a statement can throw, it alters control flow. */
2436 return tree_can_throw_internal (t);
2440 /* Return true if T is a computed goto. */
2443 computed_goto_p (tree t)
2445 return (TREE_CODE (t) == GOTO_EXPR
2446 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2450 /* Return true if T is a simple local goto. */
2453 simple_goto_p (tree t)
2455 return (TREE_CODE (t) == GOTO_EXPR
2456 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2460 /* Return true if T can make an abnormal transfer of control flow.
2461 Transfers of control flow associated with EH are excluded. */
2464 tree_can_make_abnormal_goto (tree t)
2466 if (computed_goto_p (t))
2468 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2469 t = GIMPLE_STMT_OPERAND (t, 1);
2470 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2471 t = TREE_OPERAND (t, 0);
2472 if (TREE_CODE (t) == CALL_EXPR)
2473 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2478 /* Return true if T should start a new basic block. PREV_T is the
2479 statement preceding T. It is used when T is a label or a case label.
2480 Labels should only start a new basic block if their previous statement
2481 wasn't a label. Otherwise, sequence of labels would generate
2482 unnecessary basic blocks that only contain a single label. */
2485 stmt_starts_bb_p (tree t, tree prev_t)
2490 /* LABEL_EXPRs start a new basic block only if the preceding
2491 statement wasn't a label of the same type. This prevents the
2492 creation of consecutive blocks that have nothing but a single
2494 if (TREE_CODE (t) == LABEL_EXPR)
2496 /* Nonlocal and computed GOTO targets always start a new block. */
2497 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2498 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2501 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2503 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2506 cfg_stats.num_merged_labels++;
2517 /* Return true if T should end a basic block. */
2520 stmt_ends_bb_p (tree t)
2522 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2526 /* Add gotos that used to be represented implicitly in the CFG. */
2529 disband_implicit_edges (void)
2532 block_stmt_iterator last;
2539 last = bsi_last (bb);
2540 stmt = last_stmt (bb);
2542 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2544 /* Remove superfluous gotos from COND_EXPR branches. Moved
2545 from cfg_remove_useless_stmts here since it violates the
2546 invariants for tree--cfg correspondence and thus fits better
2547 here where we do it anyway. */
2548 e = find_edge (bb, bb->next_bb);
2551 if (e->flags & EDGE_TRUE_VALUE)
2552 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2553 else if (e->flags & EDGE_FALSE_VALUE)
2554 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2557 e->flags |= EDGE_FALLTHRU;
2563 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2565 /* Remove the RETURN_EXPR if we may fall though to the exit
2567 gcc_assert (single_succ_p (bb));
2568 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2570 if (bb->next_bb == EXIT_BLOCK_PTR
2571 && !TREE_OPERAND (stmt, 0))
2573 bsi_remove (&last, true);
2574 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2579 /* There can be no fallthru edge if the last statement is a control
2581 if (stmt && is_ctrl_stmt (stmt))
2584 /* Find a fallthru edge and emit the goto if necessary. */
2585 FOR_EACH_EDGE (e, ei, bb->succs)
2586 if (e->flags & EDGE_FALLTHRU)
2589 if (!e || e->dest == bb->next_bb)
2592 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2593 label = tree_block_label (e->dest);
2595 stmt = build1 (GOTO_EXPR, void_type_node, label);
2596 #ifdef USE_MAPPED_LOCATION
2597 SET_EXPR_LOCATION (stmt, e->goto_locus);
2599 SET_EXPR_LOCUS (stmt, e->goto_locus);
2601 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2602 e->flags &= ~EDGE_FALLTHRU;
2606 /* Remove block annotations and other datastructures. */
2609 delete_tree_cfg_annotations (void)
2612 block_stmt_iterator bsi;
2614 /* Remove annotations from every tree in the function. */
2616 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2618 tree stmt = bsi_stmt (bsi);
2619 ggc_free (stmt->base.ann);
2620 stmt->base.ann = NULL;
2622 label_to_block_map = NULL;
2626 /* Return the first statement in basic block BB. */
2629 first_stmt (basic_block bb)
2631 block_stmt_iterator i = bsi_start (bb);
2632 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2636 /* Return the last statement in basic block BB. */
2639 last_stmt (basic_block bb)
2641 block_stmt_iterator b = bsi_last (bb);
2642 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2646 /* Return the last statement of an otherwise empty block. Return NULL
2647 if the block is totally empty, or if it contains more than one
2651 last_and_only_stmt (basic_block bb)
2653 block_stmt_iterator i = bsi_last (bb);
2659 last = bsi_stmt (i);
2664 /* Empty statements should no longer appear in the instruction stream.
2665 Everything that might have appeared before should be deleted by
2666 remove_useless_stmts, and the optimizers should just bsi_remove
2667 instead of smashing with build_empty_stmt.
2669 Thus the only thing that should appear here in a block containing
2670 one executable statement is a label. */
2671 prev = bsi_stmt (i);
2672 if (TREE_CODE (prev) == LABEL_EXPR)
2679 /* Mark BB as the basic block holding statement T. */
2682 set_bb_for_stmt (tree t, basic_block bb)
2684 if (TREE_CODE (t) == PHI_NODE)
2686 else if (TREE_CODE (t) == STATEMENT_LIST)
2688 tree_stmt_iterator i;
2689 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2690 set_bb_for_stmt (tsi_stmt (i), bb);
2694 stmt_ann_t ann = get_stmt_ann (t);
2697 /* If the statement is a label, add the label to block-to-labels map
2698 so that we can speed up edge creation for GOTO_EXPRs. */
2699 if (TREE_CODE (t) == LABEL_EXPR)
2703 t = LABEL_EXPR_LABEL (t);
2704 uid = LABEL_DECL_UID (t);
2707 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2708 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2709 if (old_len <= (unsigned) uid)
2711 unsigned new_len = 3 * uid / 2;
2713 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2718 /* We're moving an existing label. Make sure that we've
2719 removed it from the old block. */
2721 || !VEC_index (basic_block, label_to_block_map, uid));
2722 VEC_replace (basic_block, label_to_block_map, uid, bb);
2727 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2728 from one basic block to another.
2729 For BB splitting we can run into quadratic case, so performance is quite
2730 important and knowing that the tables are big enough, change_bb_for_stmt
2731 can inline as leaf function. */
2733 change_bb_for_stmt (tree t, basic_block bb)
2735 get_stmt_ann (t)->bb = bb;
2736 if (TREE_CODE (t) == LABEL_EXPR)
2737 VEC_replace (basic_block, label_to_block_map,
2738 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2741 /* Finds iterator for STMT. */
2743 extern block_stmt_iterator
2744 bsi_for_stmt (tree stmt)
2746 block_stmt_iterator bsi;
2748 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2749 if (bsi_stmt (bsi) == stmt)
2755 /* Mark statement T as modified, and update it. */
2757 update_modified_stmts (tree t)
2759 if (!ssa_operands_active ())
2761 if (TREE_CODE (t) == STATEMENT_LIST)
2763 tree_stmt_iterator i;
2765 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2767 stmt = tsi_stmt (i);
2768 update_stmt_if_modified (stmt);
2772 update_stmt_if_modified (t);
2775 /* Insert statement (or statement list) T before the statement
2776 pointed-to by iterator I. M specifies how to update iterator I
2777 after insertion (see enum bsi_iterator_update). */
2780 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2782 set_bb_for_stmt (t, i->bb);
2783 update_modified_stmts (t);
2784 tsi_link_before (&i->tsi, t, m);
2788 /* Insert statement (or statement list) T after the statement
2789 pointed-to by iterator I. M specifies how to update iterator I
2790 after insertion (see enum bsi_iterator_update). */
2793 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2795 set_bb_for_stmt (t, i->bb);
2796 update_modified_stmts (t);
2797 tsi_link_after (&i->tsi, t, m);
2801 /* Remove the statement pointed to by iterator I. The iterator is updated
2802 to the next statement.
2804 When REMOVE_EH_INFO is true we remove the statement pointed to by
2805 iterator I from the EH tables. Otherwise we do not modify the EH
2808 Generally, REMOVE_EH_INFO should be true when the statement is going to
2809 be removed from the IL and not reinserted elsewhere. */
2812 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2814 tree t = bsi_stmt (*i);
2815 set_bb_for_stmt (t, NULL);
2816 delink_stmt_imm_use (t);
2817 tsi_delink (&i->tsi);
2818 mark_stmt_modified (t);
2821 remove_stmt_from_eh_region (t);
2822 gimple_remove_stmt_histograms (cfun, t);
2827 /* Move the statement at FROM so it comes right after the statement at TO. */
2830 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2832 tree stmt = bsi_stmt (*from);
2833 bsi_remove (from, false);
2834 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2838 /* Move the statement at FROM so it comes right before the statement at TO. */
2841 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2843 tree stmt = bsi_stmt (*from);
2844 bsi_remove (from, false);
2845 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2849 /* Move the statement at FROM to the end of basic block BB. */
2852 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2854 block_stmt_iterator last = bsi_last (bb);
2856 /* Have to check bsi_end_p because it could be an empty block. */
2857 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2858 bsi_move_before (from, &last);
2860 bsi_move_after (from, &last);
2864 /* Replace the contents of the statement pointed to by iterator BSI
2865 with STMT. If UPDATE_EH_INFO is true, the exception handling
2866 information of the original statement is moved to the new statement. */
2869 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2872 tree orig_stmt = bsi_stmt (*bsi);
2874 if (stmt == orig_stmt)
2876 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2877 set_bb_for_stmt (stmt, bsi->bb);
2879 /* Preserve EH region information from the original statement, if
2880 requested by the caller. */
2883 eh_region = lookup_stmt_eh_region (orig_stmt);
2886 remove_stmt_from_eh_region (orig_stmt);
2887 add_stmt_to_eh_region (stmt, eh_region);
2891 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2892 gimple_remove_stmt_histograms (cfun, orig_stmt);
2893 delink_stmt_imm_use (orig_stmt);
2894 *bsi_stmt_ptr (*bsi) = stmt;
2895 mark_stmt_modified (stmt);
2896 update_modified_stmts (stmt);
2900 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2901 is made to place the statement in an existing basic block, but
2902 sometimes that isn't possible. When it isn't possible, the edge is
2903 split and the statement is added to the new block.
2905 In all cases, the returned *BSI points to the correct location. The
2906 return value is true if insertion should be done after the location,
2907 or false if it should be done before the location. If new basic block
2908 has to be created, it is stored in *NEW_BB. */
2911 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2912 basic_block *new_bb)
2914 basic_block dest, src;
2920 /* If the destination has one predecessor which has no PHI nodes,
2921 insert there. Except for the exit block.
2923 The requirement for no PHI nodes could be relaxed. Basically we
2924 would have to examine the PHIs to prove that none of them used
2925 the value set by the statement we want to insert on E. That
2926 hardly seems worth the effort. */
2927 if (single_pred_p (dest)
2928 && ! phi_nodes (dest)
2929 && dest != EXIT_BLOCK_PTR)
2931 *bsi = bsi_start (dest);
2932 if (bsi_end_p (*bsi))
2935 /* Make sure we insert after any leading labels. */
2936 tmp = bsi_stmt (*bsi);
2937 while (TREE_CODE (tmp) == LABEL_EXPR)
2940 if (bsi_end_p (*bsi))
2942 tmp = bsi_stmt (*bsi);
2945 if (bsi_end_p (*bsi))
2947 *bsi = bsi_last (dest);
2954 /* If the source has one successor, the edge is not abnormal and
2955 the last statement does not end a basic block, insert there.
2956 Except for the entry block. */
2958 if ((e->flags & EDGE_ABNORMAL) == 0
2959 && single_succ_p (src)
2960 && src != ENTRY_BLOCK_PTR)
2962 *bsi = bsi_last (src);
2963 if (bsi_end_p (*bsi))
2966 tmp = bsi_stmt (*bsi);
2967 if (!stmt_ends_bb_p (tmp))
2970 /* Insert code just before returning the value. We may need to decompose
2971 the return in the case it contains non-trivial operand. */
2972 if (TREE_CODE (tmp) == RETURN_EXPR)
2974 tree op = TREE_OPERAND (tmp, 0);
2975 if (op && !is_gimple_val (op))
2977 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
2978 bsi_insert_before (bsi, op, BSI_NEW_STMT);
2979 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
2986 /* Otherwise, create a new basic block, and split this edge. */
2987 dest = split_edge (e);
2990 e = single_pred_edge (dest);
2995 /* This routine will commit all pending edge insertions, creating any new
2996 basic blocks which are necessary. */
2999 bsi_commit_edge_inserts (void)
3005 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3008 FOR_EACH_EDGE (e, ei, bb->succs)
3009 bsi_commit_one_edge_insert (e, NULL);
3013 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3014 to this block, otherwise set it to NULL. */
3017 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3021 if (PENDING_STMT (e))
3023 block_stmt_iterator bsi;
3024 tree stmt = PENDING_STMT (e);
3026 PENDING_STMT (e) = NULL_TREE;
3028 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3029 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3031 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3036 /* Add STMT to the pending list of edge E. No actual insertion is
3037 made until a call to bsi_commit_edge_inserts () is made. */
3040 bsi_insert_on_edge (edge e, tree stmt)
3042 append_to_statement_list (stmt, &PENDING_STMT (e));
3045 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3046 block has to be created, it is returned. */
3049 bsi_insert_on_edge_immediate (edge e, tree stmt)
3051 block_stmt_iterator bsi;
3052 basic_block new_bb = NULL;
3054 gcc_assert (!PENDING_STMT (e));
3056 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3057 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3059 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3064 /*---------------------------------------------------------------------------
3065 Tree specific functions for CFG manipulation
3066 ---------------------------------------------------------------------------*/
3068 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3071 reinstall_phi_args (edge new_edge, edge old_edge)
3075 if (!PENDING_STMT (old_edge))
3078 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3080 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3082 tree result = TREE_PURPOSE (var);
3083 tree arg = TREE_VALUE (var);
3085 gcc_assert (result == PHI_RESULT (phi));
3087 add_phi_arg (phi, arg, new_edge);
3090 PENDING_STMT (old_edge) = NULL;
3093 /* Returns the basic block after which the new basic block created
3094 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3095 near its "logical" location. This is of most help to humans looking
3096 at debugging dumps. */
3099 split_edge_bb_loc (edge edge_in)
3101 basic_block dest = edge_in->dest;
3103 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3104 return edge_in->src;
3106 return dest->prev_bb;
3109 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3110 Abort on abnormal edges. */
3113 tree_split_edge (edge edge_in)
3115 basic_block new_bb, after_bb, dest;
3118 /* Abnormal edges cannot be split. */
3119 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3121 dest = edge_in->dest;
3123 after_bb = split_edge_bb_loc (edge_in);
3125 new_bb = create_empty_bb (after_bb);
3126 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3127 new_bb->count = edge_in->count;
3128 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3129 new_edge->probability = REG_BR_PROB_BASE;
3130 new_edge->count = edge_in->count;
3132 e = redirect_edge_and_branch (edge_in, new_bb);
3133 gcc_assert (e == edge_in);
3134 reinstall_phi_args (new_edge, e);
3140 /* Return true when BB has label LABEL in it. */
3143 has_label_p (basic_block bb, tree label)
3145 block_stmt_iterator bsi;
3147 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3149 tree stmt = bsi_stmt (bsi);
3151 if (TREE_CODE (stmt) != LABEL_EXPR)
3153 if (LABEL_EXPR_LABEL (stmt) == label)
3160 /* Callback for walk_tree, check that all elements with address taken are
3161 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3162 inside a PHI node. */
3165 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3168 bool in_phi = (data != NULL);
3173 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3174 #define CHECK_OP(N, MSG) \
3175 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3176 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3178 switch (TREE_CODE (t))
3181 if (SSA_NAME_IN_FREE_LIST (t))
3183 error ("SSA name in freelist but still referenced");
3189 x = fold (ASSERT_EXPR_COND (t));
3190 if (x == boolean_false_node)
3192 error ("ASSERT_EXPR with an always-false condition");
3200 case GIMPLE_MODIFY_STMT:
3201 x = GIMPLE_STMT_OPERAND (t, 0);
3202 if (TREE_CODE (x) == BIT_FIELD_REF
3203 && is_gimple_reg (TREE_OPERAND (x, 0)))
3205 error ("GIMPLE register modified with BIT_FIELD_REF");
3214 bool old_side_effects;
3217 bool new_side_effects;
3219 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3220 dead PHIs that take the address of something. But if the PHI
3221 result is dead, the fact that it takes the address of anything
3222 is irrelevant. Because we can not tell from here if a PHI result
3223 is dead, we just skip this check for PHIs altogether. This means
3224 we may be missing "valid" checks, but what can you do?
3225 This was PR19217. */
3229 old_invariant = TREE_INVARIANT (t);
3230 old_constant = TREE_CONSTANT (t);
3231 old_side_effects = TREE_SIDE_EFFECTS (t);
3233 recompute_tree_invariant_for_addr_expr (t);
3234 new_invariant = TREE_INVARIANT (t);
3235 new_side_effects = TREE_SIDE_EFFECTS (t);
3236 new_constant = TREE_CONSTANT (t);
3238 if (old_invariant != new_invariant)
3240 error ("invariant not recomputed when ADDR_EXPR changed");
3244 if (old_constant != new_constant)
3246 error ("constant not recomputed when ADDR_EXPR changed");
3249 if (old_side_effects != new_side_effects)
3251 error ("side effects not recomputed when ADDR_EXPR changed");
3255 /* Skip any references (they will be checked when we recurse down the
3256 tree) and ensure that any variable used as a prefix is marked
3258 for (x = TREE_OPERAND (t, 0);
3259 handled_component_p (x);
3260 x = TREE_OPERAND (x, 0))
3263 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3265 if (!TREE_ADDRESSABLE (x))
3267 error ("address taken, but ADDRESSABLE bit not set");
3274 x = COND_EXPR_COND (t);
3275 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3277 error ("non-boolean used in condition");
3280 if (!is_gimple_condexpr (x))
3282 error ("invalid conditional operand");
3289 case FIX_TRUNC_EXPR:
3294 case NON_LVALUE_EXPR:
3295 case TRUTH_NOT_EXPR:
3296 CHECK_OP (0, "invalid operand to unary operator");
3303 case ARRAY_RANGE_REF:
3305 case VIEW_CONVERT_EXPR:
3306 /* We have a nest of references. Verify that each of the operands
3307 that determine where to reference is either a constant or a variable,
3308 verify that the base is valid, and then show we've already checked
3310 while (handled_component_p (t))
3312 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3313 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3314 else if (TREE_CODE (t) == ARRAY_REF
3315 || TREE_CODE (t) == ARRAY_RANGE_REF)
3317 CHECK_OP (1, "invalid array index");
3318 if (TREE_OPERAND (t, 2))
3319 CHECK_OP (2, "invalid array lower bound");
3320 if (TREE_OPERAND (t, 3))
3321 CHECK_OP (3, "invalid array stride");
3323 else if (TREE_CODE (t) == BIT_FIELD_REF)
3325 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3326 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3329 t = TREE_OPERAND (t, 0);
3332 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3334 error ("invalid reference prefix");
3346 case UNORDERED_EXPR:
3357 case TRUNC_DIV_EXPR:
3359 case FLOOR_DIV_EXPR:
3360 case ROUND_DIV_EXPR:
3361 case TRUNC_MOD_EXPR:
3363 case FLOOR_MOD_EXPR:
3364 case ROUND_MOD_EXPR:
3366 case EXACT_DIV_EXPR:
3376 CHECK_OP (0, "invalid operand to binary operator");
3377 CHECK_OP (1, "invalid operand to binary operator");
3381 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3394 /* Verify STMT, return true if STMT is not in GIMPLE form.
3395 TODO: Implement type checking. */
3398 verify_stmt (tree stmt, bool last_in_block)
3402 if (OMP_DIRECTIVE_P (stmt))
3404 /* OpenMP directives are validated by the FE and never operated
3405 on by the optimizers. Furthermore, OMP_FOR may contain
3406 non-gimple expressions when the main index variable has had
3407 its address taken. This does not affect the loop itself
3408 because the header of an OMP_FOR is merely used to determine
3409 how to setup the parallel iteration. */
3413 if (!is_gimple_stmt (stmt))
3415 error ("is not a valid GIMPLE statement");
3419 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3422 debug_generic_stmt (addr);
3426 /* If the statement is marked as part of an EH region, then it is
3427 expected that the statement could throw. Verify that when we
3428 have optimizations that simplify statements such that we prove
3429 that they cannot throw, that we update other data structures
3431 if (lookup_stmt_eh_region (stmt) >= 0)
3433 if (!tree_could_throw_p (stmt))
3435 error ("statement marked for throw, but doesn%'t");
3438 if (!last_in_block && tree_can_throw_internal (stmt))
3440 error ("statement marked for throw in middle of block");
3448 debug_generic_stmt (stmt);
3453 /* Return true when the T can be shared. */
3456 tree_node_can_be_shared (tree t)
3458 if (IS_TYPE_OR_DECL_P (t)
3459 || is_gimple_min_invariant (t)
3460 || TREE_CODE (t) == SSA_NAME
3461 || t == error_mark_node
3462 || TREE_CODE (t) == IDENTIFIER_NODE)
3465 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3468 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3469 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3470 || TREE_CODE (t) == COMPONENT_REF
3471 || TREE_CODE (t) == REALPART_EXPR
3472 || TREE_CODE (t) == IMAGPART_EXPR)
3473 t = TREE_OPERAND (t, 0);
3482 /* Called via walk_trees. Verify tree sharing. */
3485 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3487 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3489 if (tree_node_can_be_shared (*tp))
3491 *walk_subtrees = false;
3495 if (pointer_set_insert (visited, *tp))
3502 /* Helper function for verify_gimple_tuples. */
3505 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3506 void *data ATTRIBUTE_UNUSED)
3508 switch (TREE_CODE (*tp))
3511 error ("unexpected non-tuple");
3521 /* Verify that there are no trees that should have been converted to
3522 gimple tuples. Return true if T contains a node that should have
3523 been converted to a gimple tuple, but hasn't. */
3526 verify_gimple_tuples (tree t)
3528 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3531 static bool eh_error_found;
3533 verify_eh_throw_stmt_node (void **slot, void *data)
3535 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3536 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3538 if (!pointer_set_contains (visited, node->stmt))
3540 error ("Dead STMT in EH table");
3541 debug_generic_stmt (node->stmt);
3542 eh_error_found = true;
3547 /* Verify the GIMPLE statement chain. */
3553 block_stmt_iterator bsi;
3555 struct pointer_set_t *visited, *visited_stmts;
3558 timevar_push (TV_TREE_STMT_VERIFY);
3559 visited = pointer_set_create ();
3560 visited_stmts = pointer_set_create ();
3567 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3569 int phi_num_args = PHI_NUM_ARGS (phi);
3571 pointer_set_insert (visited_stmts, phi);
3572 if (bb_for_stmt (phi) != bb)
3574 error ("bb_for_stmt (phi) is set to a wrong basic block");
3578 for (i = 0; i < phi_num_args; i++)
3580 tree t = PHI_ARG_DEF (phi, i);
3583 /* Addressable variables do have SSA_NAMEs but they
3584 are not considered gimple values. */
3585 if (TREE_CODE (t) != SSA_NAME
3586 && TREE_CODE (t) != FUNCTION_DECL
3587 && !is_gimple_val (t))
3589 error ("PHI def is not a GIMPLE value");
3590 debug_generic_stmt (phi);
3591 debug_generic_stmt (t);
3595 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3598 debug_generic_stmt (addr);
3602 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3605 error ("incorrect sharing of tree nodes");
3606 debug_generic_stmt (phi);
3607 debug_generic_stmt (addr);
3613 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3615 tree stmt = bsi_stmt (bsi);
3617 pointer_set_insert (visited_stmts, stmt);
3618 err |= verify_gimple_tuples (stmt);
3620 if (bb_for_stmt (stmt) != bb)
3622 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3627 err |= verify_stmt (stmt, bsi_end_p (bsi));
3628 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3631 error ("incorrect sharing of tree nodes");
3632 debug_generic_stmt (stmt);
3633 debug_generic_stmt (addr);
3638 eh_error_found = false;
3639 if (get_eh_throw_stmt_table (cfun))
3640 htab_traverse (get_eh_throw_stmt_table (cfun),
3641 verify_eh_throw_stmt_node,
3644 if (err | eh_error_found)
3645 internal_error ("verify_stmts failed");
3647 pointer_set_destroy (visited);
3648 pointer_set_destroy (visited_stmts);
3649 verify_histograms ();
3650 timevar_pop (TV_TREE_STMT_VERIFY);
3654 /* Verifies that the flow information is OK. */
3657 tree_verify_flow_info (void)
3661 block_stmt_iterator bsi;
3666 if (ENTRY_BLOCK_PTR->il.tree)
3668 error ("ENTRY_BLOCK has IL associated with it");
3672 if (EXIT_BLOCK_PTR->il.tree)
3674 error ("EXIT_BLOCK has IL associated with it");
3678 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3679 if (e->flags & EDGE_FALLTHRU)
3681 error ("fallthru to exit from bb %d", e->src->index);
3687 bool found_ctrl_stmt = false;
3691 /* Skip labels on the start of basic block. */
3692 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3694 tree prev_stmt = stmt;
3696 stmt = bsi_stmt (bsi);
3698 if (TREE_CODE (stmt) != LABEL_EXPR)
3701 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3703 error ("nonlocal label ");
3704 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3705 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3710 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3713 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3714 fprintf (stderr, " to block does not match in bb %d",
3719 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3720 != current_function_decl)
3723 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3724 fprintf (stderr, " has incorrect context in bb %d",
3730 /* Verify that body of basic block BB is free of control flow. */
3731 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3733 tree stmt = bsi_stmt (bsi);
3735 if (found_ctrl_stmt)
3737 error ("control flow in the middle of basic block %d",
3742 if (stmt_ends_bb_p (stmt))
3743 found_ctrl_stmt = true;
3745 if (TREE_CODE (stmt) == LABEL_EXPR)
3748 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3749 fprintf (stderr, " in the middle of basic block %d", bb->index);
3754 bsi = bsi_last (bb);
3755 if (bsi_end_p (bsi))
3758 stmt = bsi_stmt (bsi);
3760 err |= verify_eh_edges (stmt);
3762 if (is_ctrl_stmt (stmt))
3764 FOR_EACH_EDGE (e, ei, bb->succs)
3765 if (e->flags & EDGE_FALLTHRU)
3767 error ("fallthru edge after a control statement in bb %d",
3773 if (TREE_CODE (stmt) != COND_EXPR)
3775 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3776 after anything else but if statement. */
3777 FOR_EACH_EDGE (e, ei, bb->succs)
3778 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3780 error ("true/false edge after a non-COND_EXPR in bb %d",
3786 switch (TREE_CODE (stmt))
3792 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3793 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3795 error ("structured COND_EXPR at the end of bb %d", bb->index);
3799 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3801 if (!true_edge || !false_edge
3802 || !(true_edge->flags & EDGE_TRUE_VALUE)
3803 || !(false_edge->flags & EDGE_FALSE_VALUE)
3804 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3805 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3806 || EDGE_COUNT (bb->succs) >= 3)
3808 error ("wrong outgoing edge flags at end of bb %d",
3813 if (!has_label_p (true_edge->dest,
3814 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3816 error ("%<then%> label does not match edge at end of bb %d",
3821 if (!has_label_p (false_edge->dest,
3822 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3824 error ("%<else%> label does not match edge at end of bb %d",
3832 if (simple_goto_p (stmt))
3834 error ("explicit goto at end of bb %d", bb->index);
3839 /* FIXME. We should double check that the labels in the
3840 destination blocks have their address taken. */
3841 FOR_EACH_EDGE (e, ei, bb->succs)
3842 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3843 | EDGE_FALSE_VALUE))
3844 || !(e->flags & EDGE_ABNORMAL))
3846 error ("wrong outgoing edge flags at end of bb %d",
3854 if (!single_succ_p (bb)
3855 || (single_succ_edge (bb)->flags
3856 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3857 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3859 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3862 if (single_succ (bb) != EXIT_BLOCK_PTR)
3864 error ("return edge does not point to exit in bb %d",
3877 vec = SWITCH_LABELS (stmt);
3878 n = TREE_VEC_LENGTH (vec);
3880 /* Mark all the destination basic blocks. */
3881 for (i = 0; i < n; ++i)
3883 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3884 basic_block label_bb = label_to_block (lab);
3886 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3887 label_bb->aux = (void *)1;
3890 /* Verify that the case labels are sorted. */
3891 prev = TREE_VEC_ELT (vec, 0);
3892 for (i = 1; i < n - 1; ++i)
3894 tree c = TREE_VEC_ELT (vec, i);
3897 error ("found default case not at end of case vector");
3901 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3903 error ("case labels not sorted: ");
3904 print_generic_expr (stderr, prev, 0);
3905 fprintf (stderr," is greater than ");
3906 print_generic_expr (stderr, c, 0);
3907 fprintf (stderr," but comes before it.\n");
3912 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3914 error ("no default case found at end of case vector");
3918 FOR_EACH_EDGE (e, ei, bb->succs)
3922 error ("extra outgoing edge %d->%d",
3923 bb->index, e->dest->index);
3926 e->dest->aux = (void *)2;
3927 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3928 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3930 error ("wrong outgoing edge flags at end of bb %d",
3936 /* Check that we have all of them. */
3937 for (i = 0; i < n; ++i)
3939 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3940 basic_block label_bb = label_to_block (lab);
3942 if (label_bb->aux != (void *)2)
3944 error ("missing edge %i->%i",
3945 bb->index, label_bb->index);
3950 FOR_EACH_EDGE (e, ei, bb->succs)
3951 e->dest->aux = (void *)0;
3958 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3959 verify_dominators (CDI_DOMINATORS);
3965 /* Updates phi nodes after creating a forwarder block joined
3966 by edge FALLTHRU. */
3969 tree_make_forwarder_block (edge fallthru)
3973 basic_block dummy, bb;
3974 tree phi, new_phi, var;
3976 dummy = fallthru->src;
3977 bb = fallthru->dest;
3979 if (single_pred_p (bb))
3982 /* If we redirected a branch we must create new PHI nodes at the
3984 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3986 var = PHI_RESULT (phi);
3987 new_phi = create_phi_node (var, bb);
3988 SSA_NAME_DEF_STMT (var) = new_phi;
3989 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3990 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3993 /* Ensure that the PHI node chain is in the same order. */
3994 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3996 /* Add the arguments we have stored on edges. */
3997 FOR_EACH_EDGE (e, ei, bb->preds)
4002 flush_pending_stmts (e);
4007 /* Return a non-special label in the head of basic block BLOCK.
4008 Create one if it doesn't exist. */
4011 tree_block_label (basic_block bb)
4013 block_stmt_iterator i, s = bsi_start (bb);
4017 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4019 stmt = bsi_stmt (i);
4020 if (TREE_CODE (stmt) != LABEL_EXPR)
4022 label = LABEL_EXPR_LABEL (stmt);
4023 if (!DECL_NONLOCAL (label))
4026 bsi_move_before (&i, &s);
4031 label = create_artificial_label ();
4032 stmt = build1 (LABEL_EXPR, void_type_node, label);
4033 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4038 /* Attempt to perform edge redirection by replacing a possibly complex
4039 jump instruction by a goto or by removing the jump completely.
4040 This can apply only if all edges now point to the same block. The
4041 parameters and return values are equivalent to
4042 redirect_edge_and_branch. */
4045 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4047 basic_block src = e->src;
4048 block_stmt_iterator b;
4051 /* We can replace or remove a complex jump only when we have exactly
4053 if (EDGE_COUNT (src->succs) != 2
4054 /* Verify that all targets will be TARGET. Specifically, the
4055 edge that is not E must also go to TARGET. */
4056 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4062 stmt = bsi_stmt (b);
4064 if (TREE_CODE (stmt) == COND_EXPR
4065 || TREE_CODE (stmt) == SWITCH_EXPR)
4067 bsi_remove (&b, true);
4068 e = ssa_redirect_edge (e, target);
4069 e->flags = EDGE_FALLTHRU;
4077 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4078 edge representing the redirected branch. */
4081 tree_redirect_edge_and_branch (edge e, basic_block dest)
4083 basic_block bb = e->src;
4084 block_stmt_iterator bsi;
4088 if (e->flags & EDGE_ABNORMAL)
4091 if (e->src != ENTRY_BLOCK_PTR
4092 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4095 if (e->dest == dest)
4098 label = tree_block_label (dest);
4100 bsi = bsi_last (bb);
4101 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4103 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4106 stmt = (e->flags & EDGE_TRUE_VALUE
4107 ? COND_EXPR_THEN (stmt)
4108 : COND_EXPR_ELSE (stmt));
4109 GOTO_DESTINATION (stmt) = label;
4113 /* No non-abnormal edges should lead from a non-simple goto, and
4114 simple ones should be represented implicitly. */
4119 tree cases = get_cases_for_edge (e, stmt);
4121 /* If we have a list of cases associated with E, then use it
4122 as it's a lot faster than walking the entire case vector. */
4125 edge e2 = find_edge (e->src, dest);
4132 CASE_LABEL (cases) = label;
4133 cases = TREE_CHAIN (cases);
4136 /* If there was already an edge in the CFG, then we need
4137 to move all the cases associated with E to E2. */
4140 tree cases2 = get_cases_for_edge (e2, stmt);
4142 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4143 TREE_CHAIN (cases2) = first;
4148 tree vec = SWITCH_LABELS (stmt);
4149 size_t i, n = TREE_VEC_LENGTH (vec);
4151 for (i = 0; i < n; i++)
4153 tree elt = TREE_VEC_ELT (vec, i);
4155 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4156 CASE_LABEL (elt) = label;
4164 bsi_remove (&bsi, true);
4165 e->flags |= EDGE_FALLTHRU;
4169 /* Otherwise it must be a fallthru edge, and we don't need to
4170 do anything besides redirecting it. */
4171 gcc_assert (e->flags & EDGE_FALLTHRU);
4175 /* Update/insert PHI nodes as necessary. */
4177 /* Now update the edges in the CFG. */
4178 e = ssa_redirect_edge (e, dest);
4183 /* Returns true if it is possible to remove edge E by redirecting
4184 it to the destination of the other edge from E->src. */
4187 tree_can_remove_branch_p (edge e)
4189 if (e->flags & EDGE_ABNORMAL)
4195 /* Simple wrapper, as we can always redirect fallthru edges. */
4198 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4200 e = tree_redirect_edge_and_branch (e, dest);
4207 /* Splits basic block BB after statement STMT (but at least after the
4208 labels). If STMT is NULL, BB is split just after the labels. */
4211 tree_split_block (basic_block bb, void *stmt)
4213 block_stmt_iterator bsi;
4214 tree_stmt_iterator tsi_tgt;
4220 new_bb = create_empty_bb (bb);
4222 /* Redirect the outgoing edges. */
4223 new_bb->succs = bb->succs;
4225 FOR_EACH_EDGE (e, ei, new_bb->succs)
4228 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4231 /* Move everything from BSI to the new basic block. */
4232 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4234 act = bsi_stmt (bsi);
4235 if (TREE_CODE (act) == LABEL_EXPR)
4248 if (bsi_end_p (bsi))
4251 /* Split the statement list - avoid re-creating new containers as this
4252 brings ugly quadratic memory consumption in the inliner.
4253 (We are still quadratic since we need to update stmt BB pointers,
4255 list = tsi_split_statement_list_before (&bsi.tsi);
4256 set_bb_stmt_list (new_bb, list);
4257 for (tsi_tgt = tsi_start (list);
4258 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4259 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4265 /* Moves basic block BB after block AFTER. */
4268 tree_move_block_after (basic_block bb, basic_block after)
4270 if (bb->prev_bb == after)
4274 link_block (bb, after);
4280 /* Return true if basic_block can be duplicated. */
4283 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4289 /* Create a duplicate of the basic block BB. NOTE: This does not
4290 preserve SSA form. */
4293 tree_duplicate_bb (basic_block bb)
4296 block_stmt_iterator bsi, bsi_tgt;
4299 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4301 /* Copy the PHI nodes. We ignore PHI node arguments here because
4302 the incoming edges have not been setup yet. */
4303 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4305 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4306 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4309 /* Keep the chain of PHI nodes in the same order so that they can be
4310 updated by ssa_redirect_edge. */
4311 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4313 bsi_tgt = bsi_start (new_bb);
4314 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4316 def_operand_p def_p;
4317 ssa_op_iter op_iter;
4321 stmt = bsi_stmt (bsi);
4322 if (TREE_CODE (stmt) == LABEL_EXPR)
4325 /* Create a new copy of STMT and duplicate STMT's virtual
4327 copy = unshare_expr (stmt);
4328 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4329 copy_virtual_operands (copy, stmt);
4330 region = lookup_stmt_eh_region (stmt);
4332 add_stmt_to_eh_region (copy, region);
4333 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4335 /* Create new names for all the definitions created by COPY and
4336 add replacement mappings for each new name. */
4337 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4338 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4345 /* Basic block BB_COPY was created by code duplication. Add phi node
4346 arguments for edges going out of BB_COPY. The blocks that were
4347 duplicated have BB_DUPLICATED set. */
4350 add_phi_args_after_copy_bb (basic_block bb_copy)
4352 basic_block bb, dest;
4355 tree phi, phi_copy, phi_next, def;
4357 bb = get_bb_original (bb_copy);
4359 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4361 if (!phi_nodes (e_copy->dest))
4364 if (e_copy->dest->flags & BB_DUPLICATED)
4365 dest = get_bb_original (e_copy->dest);
4367 dest = e_copy->dest;
4369 e = find_edge (bb, dest);
4372 /* During loop unrolling the target of the latch edge is copied.
4373 In this case we are not looking for edge to dest, but to
4374 duplicated block whose original was dest. */
4375 FOR_EACH_EDGE (e, ei, bb->succs)
4376 if ((e->dest->flags & BB_DUPLICATED)
4377 && get_bb_original (e->dest) == dest)
4380 gcc_assert (e != NULL);
4383 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4385 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4387 phi_next = PHI_CHAIN (phi);
4388 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4389 add_phi_arg (phi_copy, def, e_copy);
4394 /* Blocks in REGION_COPY array of length N_REGION were created by
4395 duplication of basic blocks. Add phi node arguments for edges
4396 going from these blocks. */
4399 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4403 for (i = 0; i < n_region; i++)
4404 region_copy[i]->flags |= BB_DUPLICATED;
4406 for (i = 0; i < n_region; i++)
4407 add_phi_args_after_copy_bb (region_copy[i]);
4409 for (i = 0; i < n_region; i++)
4410 region_copy[i]->flags &= ~BB_DUPLICATED;
4413 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4414 important exit edge EXIT. By important we mean that no SSA name defined
4415 inside region is live over the other exit edges of the region. All entry
4416 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4417 to the duplicate of the region. SSA form, dominance and loop information
4418 is updated. The new basic blocks are stored to REGION_COPY in the same
4419 order as they had in REGION, provided that REGION_COPY is not NULL.
4420 The function returns false if it is unable to copy the region,
4424 tree_duplicate_sese_region (edge entry, edge exit,
4425 basic_block *region, unsigned n_region,
4426 basic_block *region_copy)
4429 bool free_region_copy = false, copying_header = false;
4430 struct loop *loop = entry->dest->loop_father;
4434 int total_freq = 0, entry_freq = 0;
4435 gcov_type total_count = 0, entry_count = 0;
4437 if (!can_copy_bbs_p (region, n_region))
4440 /* Some sanity checking. Note that we do not check for all possible
4441 missuses of the functions. I.e. if you ask to copy something weird,
4442 it will work, but the state of structures probably will not be
4444 for (i = 0; i < n_region; i++)
4446 /* We do not handle subloops, i.e. all the blocks must belong to the
4448 if (region[i]->loop_father != loop)
4451 if (region[i] != entry->dest
4452 && region[i] == loop->header)
4458 /* In case the function is used for loop header copying (which is the primary
4459 use), ensure that EXIT and its copy will be new latch and entry edges. */
4460 if (loop->header == entry->dest)
4462 copying_header = true;
4463 loop->copy = loop->outer;
4465 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4468 for (i = 0; i < n_region; i++)
4469 if (region[i] != exit->src
4470 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4476 region_copy = XNEWVEC (basic_block, n_region);
4477 free_region_copy = true;
4480 gcc_assert (!need_ssa_update_p ());
4482 /* Record blocks outside the region that are dominated by something
4484 doms = XNEWVEC (basic_block, n_basic_blocks);
4485 initialize_original_copy_tables ();
4487 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4489 if (entry->dest->count)
4491 total_count = entry->dest->count;
4492 entry_count = entry->count;
4493 /* Fix up corner cases, to avoid division by zero or creation of negative
4495 if (entry_count > total_count)
4496 entry_count = total_count;
4500 total_freq = entry->dest->frequency;
4501 entry_freq = EDGE_FREQUENCY (entry);
4502 /* Fix up corner cases, to avoid division by zero or creation of negative
4504 if (total_freq == 0)
4506 else if (entry_freq > total_freq)
4507 entry_freq = total_freq;
4510 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4511 split_edge_bb_loc (entry));
4514 scale_bbs_frequencies_gcov_type (region, n_region,
4515 total_count - entry_count,
4517 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4522 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4524 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4529 loop->header = exit->dest;
4530 loop->latch = exit->src;
4533 /* Redirect the entry and add the phi node arguments. */
4534 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4535 gcc_assert (redirected != NULL);
4536 flush_pending_stmts (entry);
4538 /* Concerning updating of dominators: We must recount dominators
4539 for entry block and its copy. Anything that is outside of the
4540 region, but was dominated by something inside needs recounting as
4542 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4543 doms[n_doms++] = get_bb_original (entry->dest);
4544 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4547 /* Add the other PHI node arguments. */
4548 add_phi_args_after_copy (region_copy, n_region);
4550 /* Update the SSA web. */
4551 update_ssa (TODO_update_ssa);
4553 if (free_region_copy)
4556 free_original_copy_tables ();
4561 DEF_VEC_P(basic_block);
4562 DEF_VEC_ALLOC_P(basic_block,heap);
4565 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4566 adding blocks when the dominator traversal reaches EXIT. This
4567 function silently assumes that ENTRY strictly dominates EXIT. */
4570 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4571 VEC(basic_block,heap) **bbs_p)
4575 for (son = first_dom_son (CDI_DOMINATORS, entry);
4577 son = next_dom_son (CDI_DOMINATORS, son))
4579 VEC_safe_push (basic_block, heap, *bbs_p, son);
4581 gather_blocks_in_sese_region (son, exit, bbs_p);
4591 bitmap vars_to_remove;
4592 htab_t new_label_map;
4596 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4597 contained in *TP and change the DECL_CONTEXT of every local
4598 variable referenced in *TP. */
4601 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4603 struct move_stmt_d *p = (struct move_stmt_d *) data;
4607 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4608 TREE_BLOCK (t) = p->block;
4610 if (OMP_DIRECTIVE_P (t)
4611 && TREE_CODE (t) != OMP_RETURN
4612 && TREE_CODE (t) != OMP_CONTINUE)
4614 /* Do not remap variables inside OMP directives. Variables
4615 referenced in clauses and directive header belong to the
4616 parent function and should not be moved into the child
4618 bool save_remap_decls_p = p->remap_decls_p;
4619 p->remap_decls_p = false;
4622 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4624 p->remap_decls_p = save_remap_decls_p;
4626 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4628 if (TREE_CODE (t) == LABEL_DECL)
4630 if (p->new_label_map)
4632 struct tree_map in, *out;
4634 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4639 DECL_CONTEXT (t) = p->to_context;
4641 else if (p->remap_decls_p)
4643 DECL_CONTEXT (t) = p->to_context;
4645 if (TREE_CODE (t) == VAR_DECL)
4647 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4648 f->unexpanded_var_list
4649 = tree_cons (0, t, f->unexpanded_var_list);
4651 /* Mark T to be removed from the original function,
4652 otherwise it will be given a DECL_RTL when the
4653 original function is expanded. */
4654 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4658 else if (TYPE_P (t))
4665 /* Move basic block BB from function CFUN to function DEST_FN. The
4666 block is moved out of the original linked list and placed after
4667 block AFTER in the new list. Also, the block is removed from the
4668 original array of blocks and placed in DEST_FN's array of blocks.
4669 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4670 updated to reflect the moved edges.
4672 On exit, local variables that need to be removed from
4673 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4676 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4677 basic_block after, bool update_edge_count_p,
4678 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4680 struct control_flow_graph *cfg;
4683 block_stmt_iterator si;
4684 struct move_stmt_d d;
4685 unsigned old_len, new_len;
4687 /* Link BB to the new linked list. */
4688 move_block_after (bb, after);
4690 /* Update the edge count in the corresponding flowgraphs. */
4691 if (update_edge_count_p)
4692 FOR_EACH_EDGE (e, ei, bb->succs)
4694 cfun->cfg->x_n_edges--;
4695 dest_cfun->cfg->x_n_edges++;
4698 /* Remove BB from the original basic block array. */
4699 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4700 cfun->cfg->x_n_basic_blocks--;
4702 /* Grow DEST_CFUN's basic block array if needed. */
4703 cfg = dest_cfun->cfg;
4704 cfg->x_n_basic_blocks++;
4705 if (bb->index > cfg->x_last_basic_block)
4706 cfg->x_last_basic_block = bb->index;
4708 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4709 if ((unsigned) cfg->x_last_basic_block >= old_len)
4711 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4712 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4716 VEC_replace (basic_block, cfg->x_basic_block_info,
4717 cfg->x_last_basic_block, bb);
4719 /* The statements in BB need to be associated with a new TREE_BLOCK.
4720 Labels need to be associated with a new label-to-block map. */
4721 memset (&d, 0, sizeof (d));
4722 d.vars_to_remove = vars_to_remove;
4724 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4726 tree stmt = bsi_stmt (si);
4729 d.from_context = cfun->decl;
4730 d.to_context = dest_cfun->decl;
4731 d.remap_decls_p = true;
4732 d.new_label_map = new_label_map;
4733 if (TREE_BLOCK (stmt))
4734 d.block = DECL_INITIAL (dest_cfun->decl);
4736 walk_tree (&stmt, move_stmt_r, &d, NULL);
4738 if (TREE_CODE (stmt) == LABEL_EXPR)
4740 tree label = LABEL_EXPR_LABEL (stmt);
4741 int uid = LABEL_DECL_UID (label);
4743 gcc_assert (uid > -1);
4745 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4746 if (old_len <= (unsigned) uid)
4748 new_len = 3 * uid / 2;
4749 VEC_safe_grow_cleared (basic_block, gc,
4750 cfg->x_label_to_block_map, new_len);
4753 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4754 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4756 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4758 if (uid >= dest_cfun->last_label_uid)
4759 dest_cfun->last_label_uid = uid + 1;
4761 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4762 TREE_OPERAND (stmt, 0) =
4763 build_int_cst (NULL_TREE,
4764 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4767 region = lookup_stmt_eh_region (stmt);
4770 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4771 remove_stmt_from_eh_region (stmt);
4772 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4773 gimple_remove_stmt_histograms (cfun, stmt);
4778 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4779 the outermost EH region. Use REGION as the incoming base EH region. */
4782 find_outermost_region_in_block (struct function *src_cfun,
4783 basic_block bb, int region)
4785 block_stmt_iterator si;
4787 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4789 tree stmt = bsi_stmt (si);
4792 if (TREE_CODE (stmt) == RESX_EXPR)
4793 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4795 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4796 if (stmt_region > 0)
4799 region = stmt_region;
4800 else if (stmt_region != region)
4802 region = eh_region_outermost (src_cfun, stmt_region, region);
4803 gcc_assert (region != -1);
4812 new_label_mapper (tree decl, void *data)
4814 htab_t hash = (htab_t) data;
4818 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4820 m = xmalloc (sizeof (struct tree_map));
4821 m->hash = DECL_UID (decl);
4822 m->base.from = decl;
4823 m->to = create_artificial_label ();
4824 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4826 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4827 gcc_assert (*slot == NULL);
4834 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4835 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4836 single basic block in the original CFG and the new basic block is
4837 returned. DEST_CFUN must not have a CFG yet.
4839 Note that the region need not be a pure SESE region. Blocks inside
4840 the region may contain calls to abort/exit. The only restriction
4841 is that ENTRY_BB should be the only entry point and it must
4844 All local variables referenced in the region are assumed to be in
4845 the corresponding BLOCK_VARS and unexpanded variable lists
4846 associated with DEST_CFUN. */
4849 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4850 basic_block exit_bb)
4852 VEC(basic_block,heap) *bbs;
4853 basic_block after, bb, *entry_pred, *exit_succ;
4854 struct function *saved_cfun;
4855 int *entry_flag, *exit_flag, eh_offset;
4856 unsigned i, num_entry_edges, num_exit_edges;
4859 bitmap vars_to_remove;
4860 htab_t new_label_map;
4864 /* Collect all the blocks in the region. Manually add ENTRY_BB
4865 because it won't be added by dfs_enumerate_from. */
4866 calculate_dominance_info (CDI_DOMINATORS);
4868 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4870 gcc_assert (entry_bb != exit_bb
4872 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4875 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4876 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4878 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4879 the predecessor edges to ENTRY_BB and the successor edges to
4880 EXIT_BB so that we can re-attach them to the new basic block that
4881 will replace the region. */
4882 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4883 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4884 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4886 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4888 entry_flag[i] = e->flags;
4889 entry_pred[i++] = e->src;
4895 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4896 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4897 sizeof (basic_block));
4898 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4900 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4902 exit_flag[i] = e->flags;
4903 exit_succ[i++] = e->dest;
4914 /* Switch context to the child function to initialize DEST_FN's CFG. */
4915 gcc_assert (dest_cfun->cfg == NULL);
4918 init_empty_tree_cfg ();
4920 /* Initialize EH information for the new function. */
4922 new_label_map = NULL;
4927 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4928 region = find_outermost_region_in_block (saved_cfun, bb, region);
4930 init_eh_for_function ();
4933 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4934 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4935 new_label_map, region, 0);
4941 /* Move blocks from BBS into DEST_CFUN. */
4942 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4943 after = dest_cfun->cfg->x_entry_block_ptr;
4944 vars_to_remove = BITMAP_ALLOC (NULL);
4945 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4947 /* No need to update edge counts on the last block. It has
4948 already been updated earlier when we detached the region from
4949 the original CFG. */
4950 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4951 new_label_map, eh_offset);
4956 htab_delete (new_label_map);
4958 /* Remove the variables marked in VARS_TO_REMOVE from
4959 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4960 DECL_RTL in the context of CFUN. */
4961 if (!bitmap_empty_p (vars_to_remove))
4965 for (p = &cfun->unexpanded_var_list; *p; )
4967 tree var = TREE_VALUE (*p);
4968 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4970 *p = TREE_CHAIN (*p);
4974 p = &TREE_CHAIN (*p);
4978 BITMAP_FREE (vars_to_remove);
4980 /* Rewire the entry and exit blocks. The successor to the entry
4981 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4982 the child function. Similarly, the predecessor of DEST_FN's
4983 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4984 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4985 various CFG manipulation function get to the right CFG.
4987 FIXME, this is silly. The CFG ought to become a parameter to
4990 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4992 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4995 /* Back in the original function, the SESE region has disappeared,
4996 create a new basic block in its place. */
4997 bb = create_empty_bb (entry_pred[0]);
4998 for (i = 0; i < num_entry_edges; i++)
4999 make_edge (entry_pred[i], bb, entry_flag[i]);
5001 for (i = 0; i < num_exit_edges; i++)
5002 make_edge (bb, exit_succ[i], exit_flag[i]);
5011 free_dominance_info (CDI_DOMINATORS);
5012 free_dominance_info (CDI_POST_DOMINATORS);
5013 VEC_free (basic_block, heap, bbs);
5019 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5022 dump_function_to_file (tree fn, FILE *file, int flags)
5024 tree arg, vars, var;
5025 struct function *dsf;
5026 bool ignore_topmost_bind = false, any_var = false;
5029 struct function *saved_cfun;
5031 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5033 arg = DECL_ARGUMENTS (fn);
5036 print_generic_expr (file, arg, dump_flags);
5037 if (TREE_CHAIN (arg))
5038 fprintf (file, ", ");
5039 arg = TREE_CHAIN (arg);
5041 fprintf (file, ")\n");
5043 dsf = DECL_STRUCT_FUNCTION (fn);
5044 if (dsf && (flags & TDF_DETAILS))
5045 dump_eh_tree (file, dsf);
5047 if (flags & TDF_RAW)
5049 dump_node (fn, TDF_SLIM | flags, file);
5053 /* Switch CFUN to point to FN. */
5055 cfun = DECL_STRUCT_FUNCTION (fn);
5057 /* When GIMPLE is lowered, the variables are no longer available in
5058 BIND_EXPRs, so display them separately. */
5059 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5061 ignore_topmost_bind = true;
5063 fprintf (file, "{\n");
5064 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5066 var = TREE_VALUE (vars);
5068 print_generic_decl (file, var, flags);
5069 fprintf (file, "\n");
5075 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5077 /* Make a CFG based dump. */
5078 check_bb_profile (ENTRY_BLOCK_PTR, file);
5079 if (!ignore_topmost_bind)
5080 fprintf (file, "{\n");
5082 if (any_var && n_basic_blocks)
5083 fprintf (file, "\n");
5086 dump_generic_bb (file, bb, 2, flags);
5088 fprintf (file, "}\n");
5089 check_bb_profile (EXIT_BLOCK_PTR, file);
5095 /* Make a tree based dump. */
5096 chain = DECL_SAVED_TREE (fn);
5098 if (chain && TREE_CODE (chain) == BIND_EXPR)
5100 if (ignore_topmost_bind)
5102 chain = BIND_EXPR_BODY (chain);
5110 if (!ignore_topmost_bind)
5111 fprintf (file, "{\n");
5116 fprintf (file, "\n");
5118 print_generic_stmt_indented (file, chain, flags, indent);
5119 if (ignore_topmost_bind)
5120 fprintf (file, "}\n");
5123 fprintf (file, "\n\n");
5130 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5133 debug_function (tree fn, int flags)
5135 dump_function_to_file (fn, stderr, flags);
5139 /* Pretty print of the loops intermediate representation. */
5140 static void print_loop (FILE *, struct loop *, int);
5141 static void print_pred_bbs (FILE *, basic_block bb);
5142 static void print_succ_bbs (FILE *, basic_block bb);
5145 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5148 print_pred_bbs (FILE *file, basic_block bb)
5153 FOR_EACH_EDGE (e, ei, bb->preds)
5154 fprintf (file, "bb_%d ", e->src->index);
5158 /* Print on FILE the indexes for the successors of basic_block BB. */
5161 print_succ_bbs (FILE *file, basic_block bb)
5166 FOR_EACH_EDGE (e, ei, bb->succs)
5167 fprintf (file, "bb_%d ", e->dest->index);
5171 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5174 print_loop (FILE *file, struct loop *loop, int indent)
5182 s_indent = (char *) alloca ((size_t) indent + 1);
5183 memset ((void *) s_indent, ' ', (size_t) indent);
5184 s_indent[indent] = '\0';
5186 /* Print the loop's header. */
5187 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5189 /* Print the loop's body. */
5190 fprintf (file, "%s{\n", s_indent);
5192 if (bb->loop_father == loop)
5194 /* Print the basic_block's header. */
5195 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5196 print_pred_bbs (file, bb);
5197 fprintf (file, "}, succs = {");
5198 print_succ_bbs (file, bb);
5199 fprintf (file, "})\n");
5201 /* Print the basic_block's body. */
5202 fprintf (file, "%s {\n", s_indent);
5203 tree_dump_bb (bb, file, indent + 4);
5204 fprintf (file, "%s }\n", s_indent);
5207 print_loop (file, loop->inner, indent + 2);
5208 fprintf (file, "%s}\n", s_indent);
5209 print_loop (file, loop->next, indent);
5213 /* Follow a CFG edge from the entry point of the program, and on entry
5214 of a loop, pretty print the loop structure on FILE. */
5217 print_loop_ir (FILE *file)
5221 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5222 if (bb && bb->loop_father)
5223 print_loop (file, bb->loop_father, 0);
5227 /* Debugging loops structure at tree level. */
5230 debug_loop_ir (void)
5232 print_loop_ir (stderr);
5236 /* Return true if BB ends with a call, possibly followed by some
5237 instructions that must stay with the call. Return false,
5241 tree_block_ends_with_call_p (basic_block bb)
5243 block_stmt_iterator bsi = bsi_last (bb);
5244 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5248 /* Return true if BB ends with a conditional branch. Return false,
5252 tree_block_ends_with_condjump_p (basic_block bb)
5254 tree stmt = last_stmt (bb);
5255 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5259 /* Return true if we need to add fake edge to exit at statement T.
5260 Helper function for tree_flow_call_edges_add. */
5263 need_fake_edge_p (tree t)
5267 /* NORETURN and LONGJMP calls already have an edge to exit.
5268 CONST and PURE calls do not need one.
5269 We don't currently check for CONST and PURE here, although
5270 it would be a good idea, because those attributes are
5271 figured out from the RTL in mark_constant_function, and
5272 the counter incrementation code from -fprofile-arcs
5273 leads to different results from -fbranch-probabilities. */
5274 call = get_call_expr_in (t);
5276 && !(call_expr_flags (call) & ECF_NORETURN))
5279 if (TREE_CODE (t) == ASM_EXPR
5280 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5287 /* Add fake edges to the function exit for any non constant and non
5288 noreturn calls, volatile inline assembly in the bitmap of blocks
5289 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5290 the number of blocks that were split.
5292 The goal is to expose cases in which entering a basic block does
5293 not imply that all subsequent instructions must be executed. */
5296 tree_flow_call_edges_add (sbitmap blocks)
5299 int blocks_split = 0;
5300 int last_bb = last_basic_block;
5301 bool check_last_block = false;
5303 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5307 check_last_block = true;
5309 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5311 /* In the last basic block, before epilogue generation, there will be
5312 a fallthru edge to EXIT. Special care is required if the last insn
5313 of the last basic block is a call because make_edge folds duplicate
5314 edges, which would result in the fallthru edge also being marked
5315 fake, which would result in the fallthru edge being removed by
5316 remove_fake_edges, which would result in an invalid CFG.
5318 Moreover, we can't elide the outgoing fake edge, since the block
5319 profiler needs to take this into account in order to solve the minimal
5320 spanning tree in the case that the call doesn't return.
5322 Handle this by adding a dummy instruction in a new last basic block. */
5323 if (check_last_block)
5325 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5326 block_stmt_iterator bsi = bsi_last (bb);
5328 if (!bsi_end_p (bsi))
5331 if (t && need_fake_edge_p (t))
5335 e = find_edge (bb, EXIT_BLOCK_PTR);
5338 bsi_insert_on_edge (e, build_empty_stmt ());
5339 bsi_commit_edge_inserts ();
5344 /* Now add fake edges to the function exit for any non constant
5345 calls since there is no way that we can determine if they will
5347 for (i = 0; i < last_bb; i++)
5349 basic_block bb = BASIC_BLOCK (i);
5350 block_stmt_iterator bsi;
5351 tree stmt, last_stmt;
5356 if (blocks && !TEST_BIT (blocks, i))
5359 bsi = bsi_last (bb);
5360 if (!bsi_end_p (bsi))
5362 last_stmt = bsi_stmt (bsi);
5365 stmt = bsi_stmt (bsi);
5366 if (need_fake_edge_p (stmt))
5369 /* The handling above of the final block before the
5370 epilogue should be enough to verify that there is
5371 no edge to the exit block in CFG already.
5372 Calling make_edge in such case would cause us to
5373 mark that edge as fake and remove it later. */
5374 #ifdef ENABLE_CHECKING
5375 if (stmt == last_stmt)
5377 e = find_edge (bb, EXIT_BLOCK_PTR);
5378 gcc_assert (e == NULL);
5382 /* Note that the following may create a new basic block
5383 and renumber the existing basic blocks. */
5384 if (stmt != last_stmt)
5386 e = split_block (bb, stmt);
5390 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5394 while (!bsi_end_p (bsi));
5399 verify_flow_info ();
5401 return blocks_split;
5404 /* Purge dead abnormal call edges from basic block BB. */
5407 tree_purge_dead_abnormal_call_edges (basic_block bb)
5409 bool changed = tree_purge_dead_eh_edges (bb);
5411 if (current_function_has_nonlocal_label)
5413 tree stmt = last_stmt (bb);
5417 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5418 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5420 if (e->flags & EDGE_ABNORMAL)
5429 /* See tree_purge_dead_eh_edges below. */
5431 free_dominance_info (CDI_DOMINATORS);
5437 /* Stores all basic blocks dominated by BB to DOM_BBS. */
5440 get_all_dominated_blocks (basic_block bb, VEC (basic_block, heap) **dom_bbs)
5444 VEC_safe_push (basic_block, heap, *dom_bbs, bb);
5445 for (son = first_dom_son (CDI_DOMINATORS, bb);
5447 son = next_dom_son (CDI_DOMINATORS, son))
5448 get_all_dominated_blocks (son, dom_bbs);
5451 /* Removes edge E and all the blocks dominated by it, and updates dominance
5452 information. The IL in E->src needs to be updated separately.
5453 If dominance info is not available, only the edge E is removed.*/
5456 remove_edge_and_dominated_blocks (edge e)
5458 VEC (basic_block, heap) *bbs_to_remove = NULL;
5459 VEC (basic_block, heap) *bbs_to_fix_dom = NULL;
5463 bool none_removed = false;
5465 basic_block bb, dbb;
5468 if (!dom_computed[CDI_DOMINATORS])
5474 /* No updating is needed for edges to exit. */
5475 if (e->dest == EXIT_BLOCK_PTR)
5477 if (cfgcleanup_altered_bbs)
5478 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5483 /* First, we find the basic blocks to remove. If E->dest has a predecessor
5484 that is not dominated by E->dest, then this set is empty. Otherwise,
5485 all the basic blocks dominated by E->dest are removed.
5487 Also, to DF_IDOM we store the immediate dominators of the blocks in
5488 the dominance frontier of E (i.e., of the successors of the
5489 removed blocks, if there are any, and of E->dest otherwise). */
5490 FOR_EACH_EDGE (f, ei, e->dest->preds)
5495 if (!dominated_by_p (CDI_DOMINATORS, f->src, e->dest))
5497 none_removed = true;
5502 df = BITMAP_ALLOC (NULL);
5503 df_idom = BITMAP_ALLOC (NULL);
5506 bitmap_set_bit (df_idom,
5507 get_immediate_dominator (CDI_DOMINATORS, e->dest)->index);
5510 get_all_dominated_blocks (e->dest, &bbs_to_remove);
5511 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5513 FOR_EACH_EDGE (f, ei, bb->succs)
5515 if (f->dest != EXIT_BLOCK_PTR)
5516 bitmap_set_bit (df, f->dest->index);
5519 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5520 bitmap_clear_bit (df, bb->index);
5522 EXECUTE_IF_SET_IN_BITMAP (df, 0, i, bi)
5524 bb = BASIC_BLOCK (i);
5525 bitmap_set_bit (df_idom,
5526 get_immediate_dominator (CDI_DOMINATORS, bb)->index);
5530 if (cfgcleanup_altered_bbs)
5532 /* Record the set of the altered basic blocks. */
5533 bitmap_set_bit (cfgcleanup_altered_bbs, e->src->index);
5534 bitmap_ior_into (cfgcleanup_altered_bbs, df);
5537 /* Remove E and the cancelled blocks. */
5542 for (i = 0; VEC_iterate (basic_block, bbs_to_remove, i, bb); i++)
5543 delete_basic_block (bb);
5546 /* Update the dominance information. The immediate dominator may change only
5547 for blocks whose immediate dominator belongs to DF_IDOM:
5549 Suppose that idom(X) = Y before removal of E and idom(X) != Y after the
5550 removal. Let Z the arbitrary block such that idom(Z) = Y and
5551 Z dominates X after the removal. Before removal, there exists a path P
5552 from Y to X that avoids Z. Let F be the last edge on P that is
5553 removed, and let W = F->dest. Before removal, idom(W) = Y (since Y
5554 dominates W, and because of P, Z does not dominate W), and W belongs to
5555 the dominance frontier of E. Therefore, Y belongs to DF_IDOM. */
5556 EXECUTE_IF_SET_IN_BITMAP (df_idom, 0, i, bi)
5558 bb = BASIC_BLOCK (i);
5559 for (dbb = first_dom_son (CDI_DOMINATORS, bb);
5561 dbb = next_dom_son (CDI_DOMINATORS, dbb))
5562 VEC_safe_push (basic_block, heap, bbs_to_fix_dom, dbb);
5565 iterate_fix_dominators (CDI_DOMINATORS,
5566 VEC_address (basic_block, bbs_to_fix_dom),
5567 VEC_length (basic_block, bbs_to_fix_dom));
5570 BITMAP_FREE (df_idom);
5571 VEC_free (basic_block, heap, bbs_to_remove);
5572 VEC_free (basic_block, heap, bbs_to_fix_dom);
5575 /* Purge dead EH edges from basic block BB. */
5578 tree_purge_dead_eh_edges (basic_block bb)
5580 bool changed = false;
5583 tree stmt = last_stmt (bb);
5585 if (stmt && tree_can_throw_internal (stmt))
5588 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5590 if (e->flags & EDGE_EH)
5592 remove_edge_and_dominated_blocks (e);
5603 tree_purge_all_dead_eh_edges (bitmap blocks)
5605 bool changed = false;
5609 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5611 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5617 /* This function is called whenever a new edge is created or
5621 tree_execute_on_growing_pred (edge e)
5623 basic_block bb = e->dest;
5626 reserve_phi_args_for_new_edge (bb);
5629 /* This function is called immediately before edge E is removed from
5630 the edge vector E->dest->preds. */
5633 tree_execute_on_shrinking_pred (edge e)
5635 if (phi_nodes (e->dest))
5636 remove_phi_args (e);
5639 /*---------------------------------------------------------------------------
5640 Helper functions for Loop versioning
5641 ---------------------------------------------------------------------------*/
5643 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5644 of 'first'. Both of them are dominated by 'new_head' basic block. When
5645 'new_head' was created by 'second's incoming edge it received phi arguments
5646 on the edge by split_edge(). Later, additional edge 'e' was created to
5647 connect 'new_head' and 'first'. Now this routine adds phi args on this
5648 additional edge 'e' that new_head to second edge received as part of edge
5653 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5654 basic_block new_head, edge e)
5657 edge e2 = find_edge (new_head, second);
5659 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5660 edge, we should always have an edge from NEW_HEAD to SECOND. */
5661 gcc_assert (e2 != NULL);
5663 /* Browse all 'second' basic block phi nodes and add phi args to
5664 edge 'e' for 'first' head. PHI args are always in correct order. */
5666 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5668 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5670 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5671 add_phi_arg (phi1, def, e);
5675 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5676 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5677 the destination of the ELSE part. */
5679 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5680 basic_block cond_bb, void *cond_e)
5682 block_stmt_iterator bsi;
5683 tree goto1 = NULL_TREE;
5684 tree goto2 = NULL_TREE;
5685 tree new_cond_expr = NULL_TREE;
5686 tree cond_expr = (tree) cond_e;
5689 /* Build new conditional expr */
5690 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5691 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5692 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5694 /* Add new cond in cond_bb. */
5695 bsi = bsi_start (cond_bb);
5696 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5697 /* Adjust edges appropriately to connect new head with first head
5698 as well as second head. */
5699 e0 = single_succ_edge (cond_bb);
5700 e0->flags &= ~EDGE_FALLTHRU;
5701 e0->flags |= EDGE_FALSE_VALUE;
5704 struct cfg_hooks tree_cfg_hooks = {
5706 tree_verify_flow_info,
5707 tree_dump_bb, /* dump_bb */
5708 create_bb, /* create_basic_block */
5709 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5710 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5711 tree_can_remove_branch_p, /* can_remove_branch_p */
5712 remove_bb, /* delete_basic_block */
5713 tree_split_block, /* split_block */
5714 tree_move_block_after, /* move_block_after */
5715 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5716 tree_merge_blocks, /* merge_blocks */
5717 tree_predict_edge, /* predict_edge */
5718 tree_predicted_by_p, /* predicted_by_p */
5719 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5720 tree_duplicate_bb, /* duplicate_block */
5721 tree_split_edge, /* split_edge */
5722 tree_make_forwarder_block, /* make_forward_block */
5723 NULL, /* tidy_fallthru_edge */
5724 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5725 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5726 tree_flow_call_edges_add, /* flow_call_edges_add */
5727 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5728 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5729 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5730 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5731 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5732 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5733 flush_pending_stmts /* flush_pending_stmts */
5737 /* Split all critical edges. */
5740 split_critical_edges (void)
5746 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5747 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5748 mappings around the calls to split_edge. */
5749 start_recording_case_labels ();
5752 FOR_EACH_EDGE (e, ei, bb->succs)
5753 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5758 end_recording_case_labels ();
5762 struct tree_opt_pass pass_split_crit_edges =
5764 "crited", /* name */
5766 split_critical_edges, /* execute */
5769 0, /* static_pass_number */
5770 TV_TREE_SPLIT_EDGES, /* tv_id */
5771 PROP_cfg, /* properties required */
5772 PROP_no_crit_edges, /* properties_provided */
5773 0, /* properties_destroyed */
5774 0, /* todo_flags_start */
5775 TODO_dump_func, /* todo_flags_finish */
5780 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5781 a temporary, make sure and register it to be renamed if necessary,
5782 and finally return the temporary. Put the statements to compute
5783 EXP before the current statement in BSI. */
5786 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5788 tree t, new_stmt, orig_stmt;
5790 if (is_gimple_val (exp))
5793 t = make_rename_temp (type, NULL);
5794 new_stmt = build_gimple_modify_stmt (t, exp);
5796 orig_stmt = bsi_stmt (*bsi);
5797 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5798 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5800 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5801 if (gimple_in_ssa_p (cfun))
5802 mark_symbols_for_renaming (new_stmt);
5807 /* Build a ternary operation and gimplify it. Emit code before BSI.
5808 Return the gimple_val holding the result. */
5811 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5812 tree type, tree a, tree b, tree c)
5816 ret = fold_build3 (code, type, a, b, c);
5819 return gimplify_val (bsi, type, ret);
5822 /* Build a binary operation and gimplify it. Emit code before BSI.
5823 Return the gimple_val holding the result. */
5826 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5827 tree type, tree a, tree b)
5831 ret = fold_build2 (code, type, a, b);
5834 return gimplify_val (bsi, type, ret);
5837 /* Build a unary operation and gimplify it. Emit code before BSI.
5838 Return the gimple_val holding the result. */
5841 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5846 ret = fold_build1 (code, type, a);
5849 return gimplify_val (bsi, type, ret);
5854 /* Emit return warnings. */
5857 execute_warn_function_return (void)
5859 #ifdef USE_MAPPED_LOCATION
5860 source_location location;
5868 /* If we have a path to EXIT, then we do return. */
5869 if (TREE_THIS_VOLATILE (cfun->decl)
5870 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5872 #ifdef USE_MAPPED_LOCATION
5873 location = UNKNOWN_LOCATION;
5877 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5879 last = last_stmt (e->src);
5880 if (TREE_CODE (last) == RETURN_EXPR
5881 #ifdef USE_MAPPED_LOCATION
5882 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5884 && (locus = EXPR_LOCUS (last)) != NULL)
5888 #ifdef USE_MAPPED_LOCATION
5889 if (location == UNKNOWN_LOCATION)
5890 location = cfun->function_end_locus;
5891 warning (0, "%H%<noreturn%> function does return", &location);
5894 locus = &cfun->function_end_locus;
5895 warning (0, "%H%<noreturn%> function does return", locus);
5899 /* If we see "return;" in some basic block, then we do reach the end
5900 without returning a value. */
5901 else if (warn_return_type
5902 && !TREE_NO_WARNING (cfun->decl)
5903 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5904 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5906 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5908 tree last = last_stmt (e->src);
5909 if (TREE_CODE (last) == RETURN_EXPR
5910 && TREE_OPERAND (last, 0) == NULL
5911 && !TREE_NO_WARNING (last))
5913 #ifdef USE_MAPPED_LOCATION
5914 location = EXPR_LOCATION (last);
5915 if (location == UNKNOWN_LOCATION)
5916 location = cfun->function_end_locus;
5917 warning (0, "%Hcontrol reaches end of non-void function", &location);
5919 locus = EXPR_LOCUS (last);
5921 locus = &cfun->function_end_locus;
5922 warning (0, "%Hcontrol reaches end of non-void function", locus);
5924 TREE_NO_WARNING (cfun->decl) = 1;
5933 /* Given a basic block B which ends with a conditional and has
5934 precisely two successors, determine which of the edges is taken if
5935 the conditional is true and which is taken if the conditional is
5936 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5939 extract_true_false_edges_from_block (basic_block b,
5943 edge e = EDGE_SUCC (b, 0);
5945 if (e->flags & EDGE_TRUE_VALUE)
5948 *false_edge = EDGE_SUCC (b, 1);
5953 *true_edge = EDGE_SUCC (b, 1);
5957 struct tree_opt_pass pass_warn_function_return =
5961 execute_warn_function_return, /* execute */
5964 0, /* static_pass_number */
5966 PROP_cfg, /* properties_required */
5967 0, /* properties_provided */
5968 0, /* properties_destroyed */
5969 0, /* todo_flags_start */
5970 0, /* todo_flags_finish */
5974 /* Emit noreturn warnings. */
5977 execute_warn_function_noreturn (void)
5979 if (warn_missing_noreturn
5980 && !TREE_THIS_VOLATILE (cfun->decl)
5981 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5982 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5983 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5984 "for attribute %<noreturn%>",
5989 struct tree_opt_pass pass_warn_function_noreturn =
5993 execute_warn_function_noreturn, /* execute */
5996 0, /* static_pass_number */
5998 PROP_cfg, /* properties_required */
5999 0, /* properties_provided */
6000 0, /* properties_destroyed */
6001 0, /* todo_flags_start */
6002 0, /* todo_flags_finish */