1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
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"
48 #include "tree-ssa-propagate.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity = 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 struct edge_to_cases_elt
73 /* The edge itself. Necessary for hashing and equality tests. */
76 /* The case labels associated with this edge. We link these up via
77 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
78 when we destroy the hash table. This prevents problems when copying
83 static htab_t edge_to_cases;
88 long num_merged_labels;
91 static struct cfg_stats_d cfg_stats;
93 /* Nonzero if we found a computed goto while building basic blocks. */
94 static bool found_computed_goto;
96 /* Basic blocks and flowgraphs. */
97 static basic_block create_bb (void *, void *, basic_block);
98 static void make_blocks (tree);
99 static void factor_computed_gotos (void);
102 static void make_edges (void);
103 static void make_cond_expr_edges (basic_block);
104 static void make_switch_expr_edges (basic_block);
105 static void make_goto_expr_edges (basic_block);
106 static edge tree_redirect_edge_and_branch (edge, basic_block);
107 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
108 static unsigned int split_critical_edges (void);
110 /* Various helpers. */
111 static inline bool stmt_starts_bb_p (tree, tree);
112 static int tree_verify_flow_info (void);
113 static void tree_make_forwarder_block (edge);
114 static void tree_cfg2vcg (FILE *);
116 /* Flowgraph optimization and cleanup. */
117 static void tree_merge_blocks (basic_block, basic_block);
118 static bool tree_can_merge_blocks_p (basic_block, basic_block);
119 static void remove_bb (basic_block);
120 static edge find_taken_edge_computed_goto (basic_block, tree);
121 static edge find_taken_edge_cond_expr (basic_block, tree);
122 static edge find_taken_edge_switch_expr (basic_block, tree);
123 static tree find_case_label_for_value (tree, tree);
126 init_empty_tree_cfg (void)
128 /* Initialize the basic block array. */
130 profile_status = PROFILE_ABSENT;
131 n_basic_blocks = NUM_FIXED_BLOCKS;
132 last_basic_block = NUM_FIXED_BLOCKS;
133 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
134 VEC_safe_grow (basic_block, gc, basic_block_info, initial_cfg_capacity);
135 memset (VEC_address (basic_block, basic_block_info), 0,
136 sizeof (basic_block) * initial_cfg_capacity);
138 /* Build a mapping of labels to their associated blocks. */
139 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
140 VEC_safe_grow (basic_block, gc, label_to_block_map, initial_cfg_capacity);
141 memset (VEC_address (basic_block, label_to_block_map),
142 0, sizeof (basic_block) * initial_cfg_capacity);
144 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
145 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
146 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
147 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
150 /*---------------------------------------------------------------------------
152 ---------------------------------------------------------------------------*/
154 /* Entry point to the CFG builder for trees. TP points to the list of
155 statements to be added to the flowgraph. */
158 build_tree_cfg (tree *tp)
160 /* Register specific tree functions. */
161 tree_register_cfg_hooks ();
163 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
165 init_empty_tree_cfg ();
167 found_computed_goto = 0;
170 /* Computed gotos are hell to deal with, especially if there are
171 lots of them with a large number of destinations. So we factor
172 them to a common computed goto location before we build the
173 edge list. After we convert back to normal form, we will un-factor
174 the computed gotos since factoring introduces an unwanted jump. */
175 if (found_computed_goto)
176 factor_computed_gotos ();
178 /* Make sure there is always at least one block, even if it's empty. */
179 if (n_basic_blocks == NUM_FIXED_BLOCKS)
180 create_empty_bb (ENTRY_BLOCK_PTR);
182 /* Adjust the size of the array. */
183 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
185 size_t old_size = VEC_length (basic_block, basic_block_info);
187 VEC_safe_grow (basic_block, gc, basic_block_info, n_basic_blocks);
188 p = VEC_address (basic_block, basic_block_info);
189 memset (&p[old_size], 0,
190 sizeof (basic_block) * (n_basic_blocks - old_size));
193 /* To speed up statement iterator walks, we first purge dead labels. */
194 cleanup_dead_labels ();
196 /* Group case nodes to reduce the number of edges.
197 We do this after cleaning up dead labels because otherwise we miss
198 a lot of obvious case merging opportunities. */
199 group_case_labels ();
201 /* Create the edges of the flowgraph. */
204 /* Debugging dumps. */
206 /* Write the flowgraph to a VCG file. */
208 int local_dump_flags;
209 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
212 tree_cfg2vcg (vcg_file);
213 dump_end (TDI_vcg, vcg_file);
217 #ifdef ENABLE_CHECKING
221 /* Dump a textual representation of the flowgraph. */
223 dump_tree_cfg (dump_file, dump_flags);
227 execute_build_cfg (void)
229 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
233 struct tree_opt_pass pass_build_cfg =
237 execute_build_cfg, /* execute */
240 0, /* static_pass_number */
241 TV_TREE_CFG, /* tv_id */
242 PROP_gimple_leh, /* properties_required */
243 PROP_cfg, /* properties_provided */
244 0, /* properties_destroyed */
245 0, /* todo_flags_start */
246 TODO_verify_stmts, /* todo_flags_finish */
250 /* Search the CFG for any computed gotos. If found, factor them to a
251 common computed goto site. Also record the location of that site so
252 that we can un-factor the gotos after we have converted back to
256 factor_computed_gotos (void)
259 tree factored_label_decl = NULL;
261 tree factored_computed_goto_label = NULL;
262 tree factored_computed_goto = NULL;
264 /* We know there are one or more computed gotos in this function.
265 Examine the last statement in each basic block to see if the block
266 ends with a computed goto. */
270 block_stmt_iterator bsi = bsi_last (bb);
275 last = bsi_stmt (bsi);
277 /* Ignore the computed goto we create when we factor the original
279 if (last == factored_computed_goto)
282 /* If the last statement is a computed goto, factor it. */
283 if (computed_goto_p (last))
287 /* The first time we find a computed goto we need to create
288 the factored goto block and the variable each original
289 computed goto will use for their goto destination. */
290 if (! factored_computed_goto)
292 basic_block new_bb = create_empty_bb (bb);
293 block_stmt_iterator new_bsi = bsi_start (new_bb);
295 /* Create the destination of the factored goto. Each original
296 computed goto will put its desired destination into this
297 variable and jump to the label we create immediately
299 var = create_tmp_var (ptr_type_node, "gotovar");
301 /* Build a label for the new block which will contain the
302 factored computed goto. */
303 factored_label_decl = create_artificial_label ();
304 factored_computed_goto_label
305 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
306 bsi_insert_after (&new_bsi, factored_computed_goto_label,
309 /* Build our new computed goto. */
310 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
311 bsi_insert_after (&new_bsi, factored_computed_goto,
315 /* Copy the original computed goto's destination into VAR. */
316 assignment = build2 (MODIFY_EXPR, ptr_type_node,
317 var, GOTO_DESTINATION (last));
318 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
320 /* And re-vector the computed goto to the new destination. */
321 GOTO_DESTINATION (last) = factored_label_decl;
327 /* Build a flowgraph for the statement_list STMT_LIST. */
330 make_blocks (tree stmt_list)
332 tree_stmt_iterator i = tsi_start (stmt_list);
334 bool start_new_block = true;
335 bool first_stmt_of_list = true;
336 basic_block bb = ENTRY_BLOCK_PTR;
338 while (!tsi_end_p (i))
345 /* If the statement starts a new basic block or if we have determined
346 in a previous pass that we need to create a new block for STMT, do
348 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
350 if (!first_stmt_of_list)
351 stmt_list = tsi_split_statement_list_before (&i);
352 bb = create_basic_block (stmt_list, NULL, bb);
353 start_new_block = false;
356 /* Now add STMT to BB and create the subgraphs for special statement
358 set_bb_for_stmt (stmt, bb);
360 if (computed_goto_p (stmt))
361 found_computed_goto = true;
363 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
365 if (stmt_ends_bb_p (stmt))
366 start_new_block = true;
369 first_stmt_of_list = false;
374 /* Create and return a new empty basic block after bb AFTER. */
377 create_bb (void *h, void *e, basic_block after)
383 /* Create and initialize a new basic block. Since alloc_block uses
384 ggc_alloc_cleared to allocate a basic block, we do not have to
385 clear the newly allocated basic block here. */
388 bb->index = last_basic_block;
390 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
392 /* Add the new block to the linked list of blocks. */
393 link_block (bb, after);
395 /* Grow the basic block array if needed. */
396 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
398 size_t old_size = VEC_length (basic_block, basic_block_info);
399 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
401 VEC_safe_grow (basic_block, gc, basic_block_info, new_size);
402 p = VEC_address (basic_block, basic_block_info);
403 memset (&p[old_size], 0, sizeof (basic_block) * (new_size - old_size));
406 /* Add the newly created block to the array. */
407 SET_BASIC_BLOCK (last_basic_block, bb);
416 /*---------------------------------------------------------------------------
418 ---------------------------------------------------------------------------*/
420 /* Fold COND_EXPR_COND of each COND_EXPR. */
423 fold_cond_expr_cond (void)
429 tree stmt = last_stmt (bb);
432 && TREE_CODE (stmt) == COND_EXPR)
434 tree cond = fold (COND_EXPR_COND (stmt));
435 if (integer_zerop (cond))
436 COND_EXPR_COND (stmt) = boolean_false_node;
437 else if (integer_onep (cond))
438 COND_EXPR_COND (stmt) = boolean_true_node;
443 /* Join all the blocks in the flowgraph. */
449 struct omp_region *cur_region = NULL;
451 /* Create an edge from entry to the first block with executable
453 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
455 /* Traverse the basic block array placing edges. */
458 tree last = last_stmt (bb);
463 enum tree_code code = TREE_CODE (last);
467 make_goto_expr_edges (bb);
471 make_edge (bb, EXIT_BLOCK_PTR, 0);
475 make_cond_expr_edges (bb);
479 make_switch_expr_edges (bb);
483 make_eh_edges (last);
488 /* If this function receives a nonlocal goto, then we need to
489 make edges from this call site to all the nonlocal goto
491 if (TREE_SIDE_EFFECTS (last)
492 && current_function_has_nonlocal_label)
493 make_goto_expr_edges (bb);
495 /* If this statement has reachable exception handlers, then
496 create abnormal edges to them. */
497 make_eh_edges (last);
499 /* Some calls are known not to return. */
500 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
504 if (is_ctrl_altering_stmt (last))
506 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
507 CALL_EXPR may have an abnormal edge. Search the RHS for
508 this case and create any required edges. */
509 tree op = get_call_expr_in (last);
510 if (op && TREE_SIDE_EFFECTS (op)
511 && current_function_has_nonlocal_label)
512 make_goto_expr_edges (bb);
514 make_eh_edges (last);
526 cur_region = new_omp_region (bb, code, cur_region);
531 cur_region = new_omp_region (bb, code, cur_region);
536 /* In the case of an OMP_SECTION, the edge will go somewhere
537 other than the next block. This will be created later. */
538 cur_region->exit = bb;
539 fallthru = cur_region->type != OMP_SECTION;
540 cur_region = cur_region->outer;
544 cur_region->cont = bb;
545 switch (cur_region->type)
548 /* ??? Technically there should be a some sort of loopback
549 edge here, but it goes to a block that doesn't exist yet,
550 and without it, updating the ssa form would be a real
551 bear. Fortunately, we don't yet do ssa before expanding
556 /* Wire up the edges into and out of the nested sections. */
557 /* ??? Similarly wrt loopback. */
559 struct omp_region *i;
560 for (i = cur_region->inner; i ; i = i->next)
562 gcc_assert (i->type == OMP_SECTION);
563 make_edge (cur_region->entry, i->entry, 0);
564 make_edge (i->exit, bb, EDGE_FALLTHRU);
576 gcc_assert (!stmt_ends_bb_p (last));
584 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
590 /* Fold COND_EXPR_COND of each COND_EXPR. */
591 fold_cond_expr_cond ();
593 /* Clean up the graph and warn for unreachable code. */
598 /* Create the edges for a COND_EXPR starting at block BB.
599 At this point, both clauses must contain only simple gotos. */
602 make_cond_expr_edges (basic_block bb)
604 tree entry = last_stmt (bb);
605 basic_block then_bb, else_bb;
606 tree then_label, else_label;
610 gcc_assert (TREE_CODE (entry) == COND_EXPR);
612 /* Entry basic blocks for each component. */
613 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
614 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
615 then_bb = label_to_block (then_label);
616 else_bb = label_to_block (else_label);
618 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
619 #ifdef USE_MAPPED_LOCATION
620 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
622 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
624 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
627 #ifdef USE_MAPPED_LOCATION
628 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
630 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
635 /* Hashing routine for EDGE_TO_CASES. */
638 edge_to_cases_hash (const void *p)
640 edge e = ((struct edge_to_cases_elt *)p)->e;
642 /* Hash on the edge itself (which is a pointer). */
643 return htab_hash_pointer (e);
646 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
647 for equality is just a pointer comparison. */
650 edge_to_cases_eq (const void *p1, const void *p2)
652 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
653 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
658 /* Called for each element in the hash table (P) as we delete the
659 edge to cases hash table.
661 Clear all the TREE_CHAINs to prevent problems with copying of
662 SWITCH_EXPRs and structure sharing rules, then free the hash table
666 edge_to_cases_cleanup (void *p)
668 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
671 for (t = elt->case_labels; t; t = next)
673 next = TREE_CHAIN (t);
674 TREE_CHAIN (t) = NULL;
679 /* Start recording information mapping edges to case labels. */
682 start_recording_case_labels (void)
684 gcc_assert (edge_to_cases == NULL);
686 edge_to_cases = htab_create (37,
689 edge_to_cases_cleanup);
692 /* Return nonzero if we are recording information for case labels. */
695 recording_case_labels_p (void)
697 return (edge_to_cases != NULL);
700 /* Stop recording information mapping edges to case labels and
701 remove any information we have recorded. */
703 end_recording_case_labels (void)
705 htab_delete (edge_to_cases);
706 edge_to_cases = NULL;
709 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
712 record_switch_edge (edge e, tree case_label)
714 struct edge_to_cases_elt *elt;
717 /* Build a hash table element so we can see if E is already
719 elt = XNEW (struct edge_to_cases_elt);
721 elt->case_labels = case_label;
723 slot = htab_find_slot (edge_to_cases, elt, INSERT);
727 /* E was not in the hash table. Install E into the hash table. */
732 /* E was already in the hash table. Free ELT as we do not need it
736 /* Get the entry stored in the hash table. */
737 elt = (struct edge_to_cases_elt *) *slot;
739 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
740 TREE_CHAIN (case_label) = elt->case_labels;
741 elt->case_labels = case_label;
745 /* If we are inside a {start,end}_recording_cases block, then return
746 a chain of CASE_LABEL_EXPRs from T which reference E.
748 Otherwise return NULL. */
751 get_cases_for_edge (edge e, tree t)
753 struct edge_to_cases_elt elt, *elt_p;
758 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
759 chains available. Return NULL so the caller can detect this case. */
760 if (!recording_case_labels_p ())
765 elt.case_labels = NULL;
766 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
770 elt_p = (struct edge_to_cases_elt *)*slot;
771 return elt_p->case_labels;
774 /* If we did not find E in the hash table, then this must be the first
775 time we have been queried for information about E & T. Add all the
776 elements from T to the hash table then perform the query again. */
778 vec = SWITCH_LABELS (t);
779 n = TREE_VEC_LENGTH (vec);
780 for (i = 0; i < n; i++)
782 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
783 basic_block label_bb = label_to_block (lab);
784 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
789 /* Create the edges for a SWITCH_EXPR starting at block BB.
790 At this point, the switch body has been lowered and the
791 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
794 make_switch_expr_edges (basic_block bb)
796 tree entry = last_stmt (bb);
800 vec = SWITCH_LABELS (entry);
801 n = TREE_VEC_LENGTH (vec);
803 for (i = 0; i < n; ++i)
805 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
806 basic_block label_bb = label_to_block (lab);
807 make_edge (bb, label_bb, 0);
812 /* Return the basic block holding label DEST. */
815 label_to_block_fn (struct function *ifun, tree dest)
817 int uid = LABEL_DECL_UID (dest);
819 /* We would die hard when faced by an undefined label. Emit a label to
820 the very first basic block. This will hopefully make even the dataflow
821 and undefined variable warnings quite right. */
822 if ((errorcount || sorrycount) && uid < 0)
824 block_stmt_iterator bsi =
825 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
828 stmt = build1 (LABEL_EXPR, void_type_node, dest);
829 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
830 uid = LABEL_DECL_UID (dest);
832 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
833 <= (unsigned int) uid)
835 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
838 /* Create edges for a goto statement at block BB. */
841 make_goto_expr_edges (basic_block bb)
844 basic_block target_bb;
846 block_stmt_iterator last = bsi_last (bb);
848 goto_t = bsi_stmt (last);
850 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
851 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
852 from a nonlocal goto. */
853 if (TREE_CODE (goto_t) != GOTO_EXPR)
857 tree dest = GOTO_DESTINATION (goto_t);
860 /* A GOTO to a local label creates normal edges. */
861 if (simple_goto_p (goto_t))
863 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
864 #ifdef USE_MAPPED_LOCATION
865 e->goto_locus = EXPR_LOCATION (goto_t);
867 e->goto_locus = EXPR_LOCUS (goto_t);
869 bsi_remove (&last, true);
873 /* Nothing more to do for nonlocal gotos. */
874 if (TREE_CODE (dest) == LABEL_DECL)
877 /* Computed gotos remain. */
880 /* Look for the block starting with the destination label. In the
881 case of a computed goto, make an edge to any label block we find
883 FOR_EACH_BB (target_bb)
885 block_stmt_iterator bsi;
887 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
889 tree target = bsi_stmt (bsi);
891 if (TREE_CODE (target) != LABEL_EXPR)
895 /* Computed GOTOs. Make an edge to every label block that has
896 been marked as a potential target for a computed goto. */
897 (FORCED_LABEL (LABEL_EXPR_LABEL (target)) && !for_call)
898 /* Nonlocal GOTO target. Make an edge to every label block
899 that has been marked as a potential target for a nonlocal
901 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target)) && for_call))
903 make_edge (bb, target_bb, EDGE_ABNORMAL);
911 /*---------------------------------------------------------------------------
913 ---------------------------------------------------------------------------*/
915 /* Cleanup useless labels in basic blocks. This is something we wish
916 to do early because it allows us to group case labels before creating
917 the edges for the CFG, and it speeds up block statement iterators in
919 We only run this pass once, running it more than once is probably not
922 /* A map from basic block index to the leading label of that block. */
923 static tree *label_for_bb;
925 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
927 update_eh_label (struct eh_region *region)
929 tree old_label = get_eh_region_tree_label (region);
933 basic_block bb = label_to_block (old_label);
935 /* ??? After optimizing, there may be EH regions with labels
936 that have already been removed from the function body, so
937 there is no basic block for them. */
941 new_label = label_for_bb[bb->index];
942 set_eh_region_tree_label (region, new_label);
946 /* Given LABEL return the first label in the same basic block. */
948 main_block_label (tree label)
950 basic_block bb = label_to_block (label);
952 /* label_to_block possibly inserted undefined label into the chain. */
953 if (!label_for_bb[bb->index])
954 label_for_bb[bb->index] = label;
955 return label_for_bb[bb->index];
958 /* Cleanup redundant labels. This is a three-step process:
959 1) Find the leading label for each block.
960 2) Redirect all references to labels to the leading labels.
961 3) Cleanup all useless labels. */
964 cleanup_dead_labels (void)
967 label_for_bb = XCNEWVEC (tree, last_basic_block);
969 /* Find a suitable label for each block. We use the first user-defined
970 label if there is one, or otherwise just the first label we see. */
973 block_stmt_iterator i;
975 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
977 tree label, stmt = bsi_stmt (i);
979 if (TREE_CODE (stmt) != LABEL_EXPR)
982 label = LABEL_EXPR_LABEL (stmt);
984 /* If we have not yet seen a label for the current block,
985 remember this one and see if there are more labels. */
986 if (! label_for_bb[bb->index])
988 label_for_bb[bb->index] = label;
992 /* If we did see a label for the current block already, but it
993 is an artificially created label, replace it if the current
994 label is a user defined label. */
995 if (! DECL_ARTIFICIAL (label)
996 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
998 label_for_bb[bb->index] = label;
1004 /* Now redirect all jumps/branches to the selected label.
1005 First do so for each block ending in a control statement. */
1008 tree stmt = last_stmt (bb);
1012 switch (TREE_CODE (stmt))
1016 tree true_branch, false_branch;
1018 true_branch = COND_EXPR_THEN (stmt);
1019 false_branch = COND_EXPR_ELSE (stmt);
1021 GOTO_DESTINATION (true_branch)
1022 = main_block_label (GOTO_DESTINATION (true_branch));
1023 GOTO_DESTINATION (false_branch)
1024 = main_block_label (GOTO_DESTINATION (false_branch));
1032 tree vec = SWITCH_LABELS (stmt);
1033 size_t n = TREE_VEC_LENGTH (vec);
1035 /* Replace all destination labels. */
1036 for (i = 0; i < n; ++i)
1038 tree elt = TREE_VEC_ELT (vec, i);
1039 tree label = main_block_label (CASE_LABEL (elt));
1040 CASE_LABEL (elt) = label;
1045 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1046 remove them until after we've created the CFG edges. */
1048 if (! computed_goto_p (stmt))
1050 GOTO_DESTINATION (stmt)
1051 = main_block_label (GOTO_DESTINATION (stmt));
1060 for_each_eh_region (update_eh_label);
1062 /* Finally, purge dead labels. All user-defined labels and labels that
1063 can be the target of non-local gotos and labels which have their
1064 address taken are preserved. */
1067 block_stmt_iterator i;
1068 tree label_for_this_bb = label_for_bb[bb->index];
1070 if (! label_for_this_bb)
1073 for (i = bsi_start (bb); !bsi_end_p (i); )
1075 tree label, stmt = bsi_stmt (i);
1077 if (TREE_CODE (stmt) != LABEL_EXPR)
1080 label = LABEL_EXPR_LABEL (stmt);
1082 if (label == label_for_this_bb
1083 || ! DECL_ARTIFICIAL (label)
1084 || DECL_NONLOCAL (label)
1085 || FORCED_LABEL (label))
1088 bsi_remove (&i, true);
1092 free (label_for_bb);
1095 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1096 and scan the sorted vector of cases. Combine the ones jumping to the
1098 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1101 group_case_labels (void)
1107 tree stmt = last_stmt (bb);
1108 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1110 tree labels = SWITCH_LABELS (stmt);
1111 int old_size = TREE_VEC_LENGTH (labels);
1112 int i, j, new_size = old_size;
1113 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1116 /* The default label is always the last case in a switch
1117 statement after gimplification. */
1118 default_label = CASE_LABEL (default_case);
1120 /* Look for possible opportunities to merge cases.
1121 Ignore the last element of the label vector because it
1122 must be the default case. */
1124 while (i < old_size - 1)
1126 tree base_case, base_label, base_high;
1127 base_case = TREE_VEC_ELT (labels, i);
1129 gcc_assert (base_case);
1130 base_label = CASE_LABEL (base_case);
1132 /* Discard cases that have the same destination as the
1134 if (base_label == default_label)
1136 TREE_VEC_ELT (labels, i) = NULL_TREE;
1142 base_high = CASE_HIGH (base_case) ?
1143 CASE_HIGH (base_case) : CASE_LOW (base_case);
1145 /* Try to merge case labels. Break out when we reach the end
1146 of the label vector or when we cannot merge the next case
1147 label with the current one. */
1148 while (i < old_size - 1)
1150 tree merge_case = TREE_VEC_ELT (labels, i);
1151 tree merge_label = CASE_LABEL (merge_case);
1152 tree t = int_const_binop (PLUS_EXPR, base_high,
1153 integer_one_node, 1);
1155 /* Merge the cases if they jump to the same place,
1156 and their ranges are consecutive. */
1157 if (merge_label == base_label
1158 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1160 base_high = CASE_HIGH (merge_case) ?
1161 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1162 CASE_HIGH (base_case) = base_high;
1163 TREE_VEC_ELT (labels, i) = NULL_TREE;
1172 /* Compress the case labels in the label vector, and adjust the
1173 length of the vector. */
1174 for (i = 0, j = 0; i < new_size; i++)
1176 while (! TREE_VEC_ELT (labels, j))
1178 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1180 TREE_VEC_LENGTH (labels) = new_size;
1185 /* Checks whether we can merge block B into block A. */
1188 tree_can_merge_blocks_p (basic_block a, basic_block b)
1191 block_stmt_iterator bsi;
1194 if (!single_succ_p (a))
1197 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1200 if (single_succ (a) != b)
1203 if (!single_pred_p (b))
1206 if (b == EXIT_BLOCK_PTR)
1209 /* If A ends by a statement causing exceptions or something similar, we
1210 cannot merge the blocks. */
1211 stmt = last_stmt (a);
1212 if (stmt && stmt_ends_bb_p (stmt))
1215 /* Do not allow a block with only a non-local label to be merged. */
1216 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1217 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1220 /* It must be possible to eliminate all phi nodes in B. If ssa form
1221 is not up-to-date, we cannot eliminate any phis. */
1222 phi = phi_nodes (b);
1225 if (need_ssa_update_p ())
1228 for (; phi; phi = PHI_CHAIN (phi))
1229 if (!is_gimple_reg (PHI_RESULT (phi))
1230 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1234 /* Do not remove user labels. */
1235 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1237 stmt = bsi_stmt (bsi);
1238 if (TREE_CODE (stmt) != LABEL_EXPR)
1240 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1244 /* Protect the loop latches. */
1246 && b->loop_father->latch == b)
1252 /* Replaces all uses of NAME by VAL. */
1255 replace_uses_by (tree name, tree val)
1257 imm_use_iterator imm_iter;
1264 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1266 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1268 replace_exp (use, val);
1270 if (TREE_CODE (stmt) == PHI_NODE)
1272 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1273 if (e->flags & EDGE_ABNORMAL)
1275 /* This can only occur for virtual operands, since
1276 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1277 would prevent replacement. */
1278 gcc_assert (!is_gimple_reg (name));
1279 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1283 if (TREE_CODE (stmt) != PHI_NODE)
1287 fold_stmt_inplace (stmt);
1288 rhs = get_rhs (stmt);
1289 if (TREE_CODE (rhs) == ADDR_EXPR)
1290 recompute_tree_invariant_for_addr_expr (rhs);
1292 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1293 mark_new_vars_to_rename (stmt);
1297 gcc_assert (num_imm_uses (name) == 0);
1299 /* Also update the trees stored in loop structures. */
1304 for (i = 0; i < current_loops->num; i++)
1306 loop = current_loops->parray[i];
1308 substitute_in_loop_info (loop, name, val);
1313 /* Merge block B into block A. */
1316 tree_merge_blocks (basic_block a, basic_block b)
1318 block_stmt_iterator bsi;
1319 tree_stmt_iterator last;
1323 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1325 /* Remove all single-valued PHI nodes from block B of the form
1326 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1328 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1330 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1332 bool may_replace_uses = may_propagate_copy (def, use);
1334 /* In case we have loops to care about, do not propagate arguments of
1335 loop closed ssa phi nodes. */
1337 && is_gimple_reg (def)
1338 && TREE_CODE (use) == SSA_NAME
1339 && a->loop_father != b->loop_father)
1340 may_replace_uses = false;
1342 if (!may_replace_uses)
1344 gcc_assert (is_gimple_reg (def));
1346 /* Note that just emitting the copies is fine -- there is no problem
1347 with ordering of phi nodes. This is because A is the single
1348 predecessor of B, therefore results of the phi nodes cannot
1349 appear as arguments of the phi nodes. */
1350 copy = build2 (MODIFY_EXPR, void_type_node, def, use);
1351 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1352 SET_PHI_RESULT (phi, NULL_TREE);
1353 SSA_NAME_DEF_STMT (def) = copy;
1356 replace_uses_by (def, use);
1358 remove_phi_node (phi, NULL);
1361 /* Ensure that B follows A. */
1362 move_block_after (b, a);
1364 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1365 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1367 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1368 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1370 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1372 tree label = bsi_stmt (bsi);
1374 bsi_remove (&bsi, false);
1375 /* Now that we can thread computed gotos, we might have
1376 a situation where we have a forced label in block B
1377 However, the label at the start of block B might still be
1378 used in other ways (think about the runtime checking for
1379 Fortran assigned gotos). So we can not just delete the
1380 label. Instead we move the label to the start of block A. */
1381 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1383 block_stmt_iterator dest_bsi = bsi_start (a);
1384 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1389 set_bb_for_stmt (bsi_stmt (bsi), a);
1394 /* Merge the chains. */
1395 last = tsi_last (a->stmt_list);
1396 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1397 b->stmt_list = NULL;
1401 /* Return the one of two successors of BB that is not reachable by a
1402 reached by a complex edge, if there is one. Else, return BB. We use
1403 this in optimizations that use post-dominators for their heuristics,
1404 to catch the cases in C++ where function calls are involved. */
1407 single_noncomplex_succ (basic_block bb)
1410 if (EDGE_COUNT (bb->succs) != 2)
1413 e0 = EDGE_SUCC (bb, 0);
1414 e1 = EDGE_SUCC (bb, 1);
1415 if (e0->flags & EDGE_COMPLEX)
1417 if (e1->flags & EDGE_COMPLEX)
1425 /* Walk the function tree removing unnecessary statements.
1427 * Empty statement nodes are removed
1429 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1431 * Unnecessary COND_EXPRs are removed
1433 * Some unnecessary BIND_EXPRs are removed
1435 Clearly more work could be done. The trick is doing the analysis
1436 and removal fast enough to be a net improvement in compile times.
1438 Note that when we remove a control structure such as a COND_EXPR
1439 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1440 to ensure we eliminate all the useless code. */
1451 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1454 remove_useless_stmts_warn_notreached (tree stmt)
1456 if (EXPR_HAS_LOCATION (stmt))
1458 location_t loc = EXPR_LOCATION (stmt);
1459 if (LOCATION_LINE (loc) > 0)
1461 warning (0, "%Hwill never be executed", &loc);
1466 switch (TREE_CODE (stmt))
1468 case STATEMENT_LIST:
1470 tree_stmt_iterator i;
1471 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1472 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1478 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1480 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1482 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1486 case TRY_FINALLY_EXPR:
1487 case TRY_CATCH_EXPR:
1488 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1490 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1495 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1496 case EH_FILTER_EXPR:
1497 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1499 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1502 /* Not a live container. */
1510 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1512 tree then_clause, else_clause, cond;
1513 bool save_has_label, then_has_label, else_has_label;
1515 save_has_label = data->has_label;
1516 data->has_label = false;
1517 data->last_goto = NULL;
1519 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1521 then_has_label = data->has_label;
1522 data->has_label = false;
1523 data->last_goto = NULL;
1525 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1527 else_has_label = data->has_label;
1528 data->has_label = save_has_label | then_has_label | else_has_label;
1530 then_clause = COND_EXPR_THEN (*stmt_p);
1531 else_clause = COND_EXPR_ELSE (*stmt_p);
1532 cond = fold (COND_EXPR_COND (*stmt_p));
1534 /* If neither arm does anything at all, we can remove the whole IF. */
1535 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1537 *stmt_p = build_empty_stmt ();
1538 data->repeat = true;
1541 /* If there are no reachable statements in an arm, then we can
1542 zap the entire conditional. */
1543 else if (integer_nonzerop (cond) && !else_has_label)
1545 if (warn_notreached)
1546 remove_useless_stmts_warn_notreached (else_clause);
1547 *stmt_p = then_clause;
1548 data->repeat = true;
1550 else if (integer_zerop (cond) && !then_has_label)
1552 if (warn_notreached)
1553 remove_useless_stmts_warn_notreached (then_clause);
1554 *stmt_p = else_clause;
1555 data->repeat = true;
1558 /* Check a couple of simple things on then/else with single stmts. */
1561 tree then_stmt = expr_only (then_clause);
1562 tree else_stmt = expr_only (else_clause);
1564 /* Notice branches to a common destination. */
1565 if (then_stmt && else_stmt
1566 && TREE_CODE (then_stmt) == GOTO_EXPR
1567 && TREE_CODE (else_stmt) == GOTO_EXPR
1568 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1570 *stmt_p = then_stmt;
1571 data->repeat = true;
1574 /* If the THEN/ELSE clause merely assigns a value to a variable or
1575 parameter which is already known to contain that value, then
1576 remove the useless THEN/ELSE clause. */
1577 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1580 && TREE_CODE (else_stmt) == MODIFY_EXPR
1581 && TREE_OPERAND (else_stmt, 0) == cond
1582 && integer_zerop (TREE_OPERAND (else_stmt, 1)))
1583 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1585 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1586 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1587 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1588 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1590 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1591 ? then_stmt : else_stmt);
1592 tree *location = (TREE_CODE (cond) == EQ_EXPR
1593 ? &COND_EXPR_THEN (*stmt_p)
1594 : &COND_EXPR_ELSE (*stmt_p));
1597 && TREE_CODE (stmt) == MODIFY_EXPR
1598 && TREE_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1599 && TREE_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1600 *location = alloc_stmt_list ();
1604 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1605 would be re-introduced during lowering. */
1606 data->last_goto = NULL;
1611 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1613 bool save_may_branch, save_may_throw;
1614 bool this_may_branch, this_may_throw;
1616 /* Collect may_branch and may_throw information for the body only. */
1617 save_may_branch = data->may_branch;
1618 save_may_throw = data->may_throw;
1619 data->may_branch = false;
1620 data->may_throw = false;
1621 data->last_goto = NULL;
1623 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1625 this_may_branch = data->may_branch;
1626 this_may_throw = data->may_throw;
1627 data->may_branch |= save_may_branch;
1628 data->may_throw |= save_may_throw;
1629 data->last_goto = NULL;
1631 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1633 /* If the body is empty, then we can emit the FINALLY block without
1634 the enclosing TRY_FINALLY_EXPR. */
1635 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1637 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1638 data->repeat = true;
1641 /* If the handler is empty, then we can emit the TRY block without
1642 the enclosing TRY_FINALLY_EXPR. */
1643 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1645 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1646 data->repeat = true;
1649 /* If the body neither throws, nor branches, then we can safely
1650 string the TRY and FINALLY blocks together. */
1651 else if (!this_may_branch && !this_may_throw)
1653 tree stmt = *stmt_p;
1654 *stmt_p = TREE_OPERAND (stmt, 0);
1655 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1656 data->repeat = true;
1662 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1664 bool save_may_throw, this_may_throw;
1665 tree_stmt_iterator i;
1668 /* Collect may_throw information for the body only. */
1669 save_may_throw = data->may_throw;
1670 data->may_throw = false;
1671 data->last_goto = NULL;
1673 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1675 this_may_throw = data->may_throw;
1676 data->may_throw = save_may_throw;
1678 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1679 if (!this_may_throw)
1681 if (warn_notreached)
1682 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1683 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1684 data->repeat = true;
1688 /* Process the catch clause specially. We may be able to tell that
1689 no exceptions propagate past this point. */
1691 this_may_throw = true;
1692 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1693 stmt = tsi_stmt (i);
1694 data->last_goto = NULL;
1696 switch (TREE_CODE (stmt))
1699 for (; !tsi_end_p (i); tsi_next (&i))
1701 stmt = tsi_stmt (i);
1702 /* If we catch all exceptions, then the body does not
1703 propagate exceptions past this point. */
1704 if (CATCH_TYPES (stmt) == NULL)
1705 this_may_throw = false;
1706 data->last_goto = NULL;
1707 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1711 case EH_FILTER_EXPR:
1712 if (EH_FILTER_MUST_NOT_THROW (stmt))
1713 this_may_throw = false;
1714 else if (EH_FILTER_TYPES (stmt) == NULL)
1715 this_may_throw = false;
1716 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1720 /* Otherwise this is a cleanup. */
1721 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1723 /* If the cleanup is empty, then we can emit the TRY block without
1724 the enclosing TRY_CATCH_EXPR. */
1725 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1727 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1728 data->repeat = true;
1732 data->may_throw |= this_may_throw;
1737 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1741 /* First remove anything underneath the BIND_EXPR. */
1742 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1744 /* If the BIND_EXPR has no variables, then we can pull everything
1745 up one level and remove the BIND_EXPR, unless this is the toplevel
1746 BIND_EXPR for the current function or an inlined function.
1748 When this situation occurs we will want to apply this
1749 optimization again. */
1750 block = BIND_EXPR_BLOCK (*stmt_p);
1751 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1752 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1754 || ! BLOCK_ABSTRACT_ORIGIN (block)
1755 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1758 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1759 data->repeat = true;
1765 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1767 tree dest = GOTO_DESTINATION (*stmt_p);
1769 data->may_branch = true;
1770 data->last_goto = NULL;
1772 /* Record the last goto expr, so that we can delete it if unnecessary. */
1773 if (TREE_CODE (dest) == LABEL_DECL)
1774 data->last_goto = stmt_p;
1779 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1781 tree label = LABEL_EXPR_LABEL (*stmt_p);
1783 data->has_label = true;
1785 /* We do want to jump across non-local label receiver code. */
1786 if (DECL_NONLOCAL (label))
1787 data->last_goto = NULL;
1789 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1791 *data->last_goto = build_empty_stmt ();
1792 data->repeat = true;
1795 /* ??? Add something here to delete unused labels. */
1799 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1800 decl. This allows us to eliminate redundant or useless
1801 calls to "const" functions.
1803 Gimplifier already does the same operation, but we may notice functions
1804 being const and pure once their calls has been gimplified, so we need
1805 to update the flag. */
1808 update_call_expr_flags (tree call)
1810 tree decl = get_callee_fndecl (call);
1813 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1814 TREE_SIDE_EFFECTS (call) = 0;
1815 if (TREE_NOTHROW (decl))
1816 TREE_NOTHROW (call) = 1;
1820 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1823 notice_special_calls (tree t)
1825 int flags = call_expr_flags (t);
1827 if (flags & ECF_MAY_BE_ALLOCA)
1828 current_function_calls_alloca = true;
1829 if (flags & ECF_RETURNS_TWICE)
1830 current_function_calls_setjmp = true;
1834 /* Clear flags set by notice_special_calls. Used by dead code removal
1835 to update the flags. */
1838 clear_special_calls (void)
1840 current_function_calls_alloca = false;
1841 current_function_calls_setjmp = false;
1846 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1850 switch (TREE_CODE (t))
1853 remove_useless_stmts_cond (tp, data);
1856 case TRY_FINALLY_EXPR:
1857 remove_useless_stmts_tf (tp, data);
1860 case TRY_CATCH_EXPR:
1861 remove_useless_stmts_tc (tp, data);
1865 remove_useless_stmts_bind (tp, data);
1869 remove_useless_stmts_goto (tp, data);
1873 remove_useless_stmts_label (tp, data);
1878 data->last_goto = NULL;
1879 data->may_branch = true;
1884 data->last_goto = NULL;
1885 notice_special_calls (t);
1886 update_call_expr_flags (t);
1887 if (tree_could_throw_p (t))
1888 data->may_throw = true;
1892 data->last_goto = NULL;
1894 op = get_call_expr_in (t);
1897 update_call_expr_flags (op);
1898 notice_special_calls (op);
1900 if (tree_could_throw_p (t))
1901 data->may_throw = true;
1904 case STATEMENT_LIST:
1906 tree_stmt_iterator i = tsi_start (t);
1907 while (!tsi_end_p (i))
1910 if (IS_EMPTY_STMT (t))
1916 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1919 if (TREE_CODE (t) == STATEMENT_LIST)
1921 tsi_link_before (&i, t, TSI_SAME_STMT);
1931 data->last_goto = NULL;
1935 data->last_goto = NULL;
1941 remove_useless_stmts (void)
1943 struct rus_data data;
1945 clear_special_calls ();
1949 memset (&data, 0, sizeof (data));
1950 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1952 while (data.repeat);
1957 struct tree_opt_pass pass_remove_useless_stmts =
1959 "useless", /* name */
1961 remove_useless_stmts, /* execute */
1964 0, /* static_pass_number */
1966 PROP_gimple_any, /* properties_required */
1967 0, /* properties_provided */
1968 0, /* properties_destroyed */
1969 0, /* todo_flags_start */
1970 TODO_dump_func, /* todo_flags_finish */
1974 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1977 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1981 /* Since this block is no longer reachable, we can just delete all
1982 of its PHI nodes. */
1983 phi = phi_nodes (bb);
1986 tree next = PHI_CHAIN (phi);
1987 remove_phi_node (phi, NULL_TREE);
1991 /* Remove edges to BB's successors. */
1992 while (EDGE_COUNT (bb->succs) > 0)
1993 remove_edge (EDGE_SUCC (bb, 0));
1997 /* Remove statements of basic block BB. */
2000 remove_bb (basic_block bb)
2002 block_stmt_iterator i;
2003 #ifdef USE_MAPPED_LOCATION
2004 source_location loc = UNKNOWN_LOCATION;
2006 source_locus loc = 0;
2011 fprintf (dump_file, "Removing basic block %d\n", bb->index);
2012 if (dump_flags & TDF_DETAILS)
2014 dump_bb (bb, dump_file, 0);
2015 fprintf (dump_file, "\n");
2019 /* If we remove the header or the latch of a loop, mark the loop for
2020 removal by setting its header and latch to NULL. */
2023 struct loop *loop = bb->loop_father;
2025 if (loop->latch == bb
2026 || loop->header == bb)
2029 loop->header = NULL;
2031 /* Also clean up the information associated with the loop. Updating
2032 it would waste time. More importantly, it may refer to ssa
2033 names that were defined in other removed basic block -- these
2034 ssa names are now removed and invalid. */
2035 free_numbers_of_iterations_estimates_loop (loop);
2039 /* Remove all the instructions in the block. */
2040 for (i = bsi_start (bb); !bsi_end_p (i);)
2042 tree stmt = bsi_stmt (i);
2043 if (TREE_CODE (stmt) == LABEL_EXPR
2044 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2045 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2048 block_stmt_iterator new_bsi;
2050 /* A non-reachable non-local label may still be referenced.
2051 But it no longer needs to carry the extra semantics of
2053 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2055 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2056 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2059 new_bb = bb->prev_bb;
2060 new_bsi = bsi_start (new_bb);
2061 bsi_remove (&i, false);
2062 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2066 /* Release SSA definitions if we are in SSA. Note that we
2067 may be called when not in SSA. For example,
2068 final_cleanup calls this function via
2069 cleanup_tree_cfg. */
2071 release_defs (stmt);
2073 bsi_remove (&i, true);
2076 /* Don't warn for removed gotos. Gotos are often removed due to
2077 jump threading, thus resulting in bogus warnings. Not great,
2078 since this way we lose warnings for gotos in the original
2079 program that are indeed unreachable. */
2080 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2082 #ifdef USE_MAPPED_LOCATION
2083 if (EXPR_HAS_LOCATION (stmt))
2084 loc = EXPR_LOCATION (stmt);
2087 t = EXPR_LOCUS (stmt);
2088 if (t && LOCATION_LINE (*t) > 0)
2094 /* If requested, give a warning that the first statement in the
2095 block is unreachable. We walk statements backwards in the
2096 loop above, so the last statement we process is the first statement
2098 #ifdef USE_MAPPED_LOCATION
2099 if (loc > BUILTINS_LOCATION)
2100 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2103 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2106 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2110 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2111 predicate VAL, return the edge that will be taken out of the block.
2112 If VAL does not match a unique edge, NULL is returned. */
2115 find_taken_edge (basic_block bb, tree val)
2119 stmt = last_stmt (bb);
2122 gcc_assert (is_ctrl_stmt (stmt));
2125 if (! is_gimple_min_invariant (val))
2128 if (TREE_CODE (stmt) == COND_EXPR)
2129 return find_taken_edge_cond_expr (bb, val);
2131 if (TREE_CODE (stmt) == SWITCH_EXPR)
2132 return find_taken_edge_switch_expr (bb, val);
2134 if (computed_goto_p (stmt))
2135 return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
2140 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2141 statement, determine which of the outgoing edges will be taken out of the
2142 block. Return NULL if either edge may be taken. */
2145 find_taken_edge_computed_goto (basic_block bb, tree val)
2150 dest = label_to_block (val);
2153 e = find_edge (bb, dest);
2154 gcc_assert (e != NULL);
2160 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2161 statement, determine which of the two edges will be taken out of the
2162 block. Return NULL if either edge may be taken. */
2165 find_taken_edge_cond_expr (basic_block bb, tree val)
2167 edge true_edge, false_edge;
2169 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2171 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2172 return (zero_p (val) ? false_edge : true_edge);
2175 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2176 statement, determine which edge will be taken out of the block. Return
2177 NULL if any edge may be taken. */
2180 find_taken_edge_switch_expr (basic_block bb, tree val)
2182 tree switch_expr, taken_case;
2183 basic_block dest_bb;
2186 switch_expr = last_stmt (bb);
2187 taken_case = find_case_label_for_value (switch_expr, val);
2188 dest_bb = label_to_block (CASE_LABEL (taken_case));
2190 e = find_edge (bb, dest_bb);
2196 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2197 We can make optimal use here of the fact that the case labels are
2198 sorted: We can do a binary search for a case matching VAL. */
2201 find_case_label_for_value (tree switch_expr, tree val)
2203 tree vec = SWITCH_LABELS (switch_expr);
2204 size_t low, high, n = TREE_VEC_LENGTH (vec);
2205 tree default_case = TREE_VEC_ELT (vec, n - 1);
2207 for (low = -1, high = n - 1; high - low > 1; )
2209 size_t i = (high + low) / 2;
2210 tree t = TREE_VEC_ELT (vec, i);
2213 /* Cache the result of comparing CASE_LOW and val. */
2214 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2221 if (CASE_HIGH (t) == NULL)
2223 /* A singe-valued case label. */
2229 /* A case range. We can only handle integer ranges. */
2230 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2235 return default_case;
2241 /*---------------------------------------------------------------------------
2243 ---------------------------------------------------------------------------*/
2245 /* Dump tree-specific information of block BB to file OUTF. */
2248 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2250 dump_generic_bb (outf, bb, indent, TDF_VOPS);
2254 /* Dump a basic block on stderr. */
2257 debug_tree_bb (basic_block bb)
2259 dump_bb (bb, stderr, 0);
2263 /* Dump basic block with index N on stderr. */
2266 debug_tree_bb_n (int n)
2268 debug_tree_bb (BASIC_BLOCK (n));
2269 return BASIC_BLOCK (n);
2273 /* Dump the CFG on stderr.
2275 FLAGS are the same used by the tree dumping functions
2276 (see TDF_* in tree.h). */
2279 debug_tree_cfg (int flags)
2281 dump_tree_cfg (stderr, flags);
2285 /* Dump the program showing basic block boundaries on the given FILE.
2287 FLAGS are the same used by the tree dumping functions (see TDF_* in
2291 dump_tree_cfg (FILE *file, int flags)
2293 if (flags & TDF_DETAILS)
2295 const char *funcname
2296 = lang_hooks.decl_printable_name (current_function_decl, 2);
2299 fprintf (file, ";; Function %s\n\n", funcname);
2300 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2301 n_basic_blocks, n_edges, last_basic_block);
2303 brief_dump_cfg (file);
2304 fprintf (file, "\n");
2307 if (flags & TDF_STATS)
2308 dump_cfg_stats (file);
2310 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2314 /* Dump CFG statistics on FILE. */
2317 dump_cfg_stats (FILE *file)
2319 static long max_num_merged_labels = 0;
2320 unsigned long size, total = 0;
2323 const char * const fmt_str = "%-30s%-13s%12s\n";
2324 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2325 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2326 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2327 const char *funcname
2328 = lang_hooks.decl_printable_name (current_function_decl, 2);
2331 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2333 fprintf (file, "---------------------------------------------------------\n");
2334 fprintf (file, fmt_str, "", " Number of ", "Memory");
2335 fprintf (file, fmt_str, "", " instances ", "used ");
2336 fprintf (file, "---------------------------------------------------------\n");
2338 size = n_basic_blocks * sizeof (struct basic_block_def);
2340 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2341 SCALE (size), LABEL (size));
2345 num_edges += EDGE_COUNT (bb->succs);
2346 size = num_edges * sizeof (struct edge_def);
2348 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2350 fprintf (file, "---------------------------------------------------------\n");
2351 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2353 fprintf (file, "---------------------------------------------------------\n");
2354 fprintf (file, "\n");
2356 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2357 max_num_merged_labels = cfg_stats.num_merged_labels;
2359 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2360 cfg_stats.num_merged_labels, max_num_merged_labels);
2362 fprintf (file, "\n");
2366 /* Dump CFG statistics on stderr. Keep extern so that it's always
2367 linked in the final executable. */
2370 debug_cfg_stats (void)
2372 dump_cfg_stats (stderr);
2376 /* Dump the flowgraph to a .vcg FILE. */
2379 tree_cfg2vcg (FILE *file)
2384 const char *funcname
2385 = lang_hooks.decl_printable_name (current_function_decl, 2);
2387 /* Write the file header. */
2388 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2389 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2390 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2392 /* Write blocks and edges. */
2393 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2395 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2398 if (e->flags & EDGE_FAKE)
2399 fprintf (file, " linestyle: dotted priority: 10");
2401 fprintf (file, " linestyle: solid priority: 100");
2403 fprintf (file, " }\n");
2409 enum tree_code head_code, end_code;
2410 const char *head_name, *end_name;
2413 tree first = first_stmt (bb);
2414 tree last = last_stmt (bb);
2418 head_code = TREE_CODE (first);
2419 head_name = tree_code_name[head_code];
2420 head_line = get_lineno (first);
2423 head_name = "no-statement";
2427 end_code = TREE_CODE (last);
2428 end_name = tree_code_name[end_code];
2429 end_line = get_lineno (last);
2432 end_name = "no-statement";
2434 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2435 bb->index, bb->index, head_name, head_line, end_name,
2438 FOR_EACH_EDGE (e, ei, bb->succs)
2440 if (e->dest == EXIT_BLOCK_PTR)
2441 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2443 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2445 if (e->flags & EDGE_FAKE)
2446 fprintf (file, " priority: 10 linestyle: dotted");
2448 fprintf (file, " priority: 100 linestyle: solid");
2450 fprintf (file, " }\n");
2453 if (bb->next_bb != EXIT_BLOCK_PTR)
2457 fputs ("}\n\n", file);
2462 /*---------------------------------------------------------------------------
2463 Miscellaneous helpers
2464 ---------------------------------------------------------------------------*/
2466 /* Return true if T represents a stmt that always transfers control. */
2469 is_ctrl_stmt (tree t)
2471 return (TREE_CODE (t) == COND_EXPR
2472 || TREE_CODE (t) == SWITCH_EXPR
2473 || TREE_CODE (t) == GOTO_EXPR
2474 || TREE_CODE (t) == RETURN_EXPR
2475 || TREE_CODE (t) == RESX_EXPR);
2479 /* Return true if T is a statement that may alter the flow of control
2480 (e.g., a call to a non-returning function). */
2483 is_ctrl_altering_stmt (tree t)
2488 call = get_call_expr_in (t);
2491 /* A non-pure/const CALL_EXPR alters flow control if the current
2492 function has nonlocal labels. */
2493 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2496 /* A CALL_EXPR also alters control flow if it does not return. */
2497 if (call_expr_flags (call) & ECF_NORETURN)
2501 /* OpenMP directives alter control flow. */
2502 if (OMP_DIRECTIVE_P (t))
2505 /* If a statement can throw, it alters control flow. */
2506 return tree_can_throw_internal (t);
2510 /* Return true if T is a computed goto. */
2513 computed_goto_p (tree t)
2515 return (TREE_CODE (t) == GOTO_EXPR
2516 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2520 /* Checks whether EXPR is a simple local goto. */
2523 simple_goto_p (tree expr)
2525 return (TREE_CODE (expr) == GOTO_EXPR
2526 && TREE_CODE (GOTO_DESTINATION (expr)) == LABEL_DECL);
2530 /* Return true if T should start a new basic block. PREV_T is the
2531 statement preceding T. It is used when T is a label or a case label.
2532 Labels should only start a new basic block if their previous statement
2533 wasn't a label. Otherwise, sequence of labels would generate
2534 unnecessary basic blocks that only contain a single label. */
2537 stmt_starts_bb_p (tree t, tree prev_t)
2542 /* LABEL_EXPRs start a new basic block only if the preceding
2543 statement wasn't a label of the same type. This prevents the
2544 creation of consecutive blocks that have nothing but a single
2546 if (TREE_CODE (t) == LABEL_EXPR)
2548 /* Nonlocal and computed GOTO targets always start a new block. */
2549 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2550 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2553 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2555 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2558 cfg_stats.num_merged_labels++;
2569 /* Return true if T should end a basic block. */
2572 stmt_ends_bb_p (tree t)
2574 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2578 /* Add gotos that used to be represented implicitly in the CFG. */
2581 disband_implicit_edges (void)
2584 block_stmt_iterator last;
2591 last = bsi_last (bb);
2592 stmt = last_stmt (bb);
2594 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2596 /* Remove superfluous gotos from COND_EXPR branches. Moved
2597 from cfg_remove_useless_stmts here since it violates the
2598 invariants for tree--cfg correspondence and thus fits better
2599 here where we do it anyway. */
2600 e = find_edge (bb, bb->next_bb);
2603 if (e->flags & EDGE_TRUE_VALUE)
2604 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2605 else if (e->flags & EDGE_FALSE_VALUE)
2606 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2609 e->flags |= EDGE_FALLTHRU;
2615 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2617 /* Remove the RETURN_EXPR if we may fall though to the exit
2619 gcc_assert (single_succ_p (bb));
2620 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2622 if (bb->next_bb == EXIT_BLOCK_PTR
2623 && !TREE_OPERAND (stmt, 0))
2625 bsi_remove (&last, true);
2626 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2631 /* There can be no fallthru edge if the last statement is a control
2633 if (stmt && is_ctrl_stmt (stmt))
2636 /* Find a fallthru edge and emit the goto if necessary. */
2637 FOR_EACH_EDGE (e, ei, bb->succs)
2638 if (e->flags & EDGE_FALLTHRU)
2641 if (!e || e->dest == bb->next_bb)
2644 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2645 label = tree_block_label (e->dest);
2647 stmt = build1 (GOTO_EXPR, void_type_node, label);
2648 #ifdef USE_MAPPED_LOCATION
2649 SET_EXPR_LOCATION (stmt, e->goto_locus);
2651 SET_EXPR_LOCUS (stmt, e->goto_locus);
2653 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2654 e->flags &= ~EDGE_FALLTHRU;
2658 /* Remove block annotations and other datastructures. */
2661 delete_tree_cfg_annotations (void)
2663 label_to_block_map = NULL;
2667 /* Return the first statement in basic block BB. */
2670 first_stmt (basic_block bb)
2672 block_stmt_iterator i = bsi_start (bb);
2673 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2677 /* Return the last statement in basic block BB. */
2680 last_stmt (basic_block bb)
2682 block_stmt_iterator b = bsi_last (bb);
2683 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2687 /* Return a pointer to the last statement in block BB. */
2690 last_stmt_ptr (basic_block bb)
2692 block_stmt_iterator last = bsi_last (bb);
2693 return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL;
2697 /* Return the last statement of an otherwise empty block. Return NULL
2698 if the block is totally empty, or if it contains more than one
2702 last_and_only_stmt (basic_block bb)
2704 block_stmt_iterator i = bsi_last (bb);
2710 last = bsi_stmt (i);
2715 /* Empty statements should no longer appear in the instruction stream.
2716 Everything that might have appeared before should be deleted by
2717 remove_useless_stmts, and the optimizers should just bsi_remove
2718 instead of smashing with build_empty_stmt.
2720 Thus the only thing that should appear here in a block containing
2721 one executable statement is a label. */
2722 prev = bsi_stmt (i);
2723 if (TREE_CODE (prev) == LABEL_EXPR)
2730 /* Mark BB as the basic block holding statement T. */
2733 set_bb_for_stmt (tree t, basic_block bb)
2735 if (TREE_CODE (t) == PHI_NODE)
2737 else if (TREE_CODE (t) == STATEMENT_LIST)
2739 tree_stmt_iterator i;
2740 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2741 set_bb_for_stmt (tsi_stmt (i), bb);
2745 stmt_ann_t ann = get_stmt_ann (t);
2748 /* If the statement is a label, add the label to block-to-labels map
2749 so that we can speed up edge creation for GOTO_EXPRs. */
2750 if (TREE_CODE (t) == LABEL_EXPR)
2754 t = LABEL_EXPR_LABEL (t);
2755 uid = LABEL_DECL_UID (t);
2758 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2759 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2760 if (old_len <= (unsigned) uid)
2763 unsigned new_len = 3 * uid / 2;
2765 VEC_safe_grow (basic_block, gc, label_to_block_map,
2767 addr = VEC_address (basic_block, label_to_block_map);
2768 memset (&addr[old_len],
2769 0, sizeof (basic_block) * (new_len - old_len));
2773 /* We're moving an existing label. Make sure that we've
2774 removed it from the old block. */
2776 || !VEC_index (basic_block, label_to_block_map, uid));
2777 VEC_replace (basic_block, label_to_block_map, uid, bb);
2782 /* Finds iterator for STMT. */
2784 extern block_stmt_iterator
2785 bsi_for_stmt (tree stmt)
2787 block_stmt_iterator bsi;
2789 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2790 if (bsi_stmt (bsi) == stmt)
2796 /* Mark statement T as modified, and update it. */
2798 update_modified_stmts (tree t)
2800 if (TREE_CODE (t) == STATEMENT_LIST)
2802 tree_stmt_iterator i;
2804 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2806 stmt = tsi_stmt (i);
2807 update_stmt_if_modified (stmt);
2811 update_stmt_if_modified (t);
2814 /* Insert statement (or statement list) T before the statement
2815 pointed-to by iterator I. M specifies how to update iterator I
2816 after insertion (see enum bsi_iterator_update). */
2819 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2821 set_bb_for_stmt (t, i->bb);
2822 update_modified_stmts (t);
2823 tsi_link_before (&i->tsi, t, m);
2827 /* Insert statement (or statement list) T after the statement
2828 pointed-to by iterator I. M specifies how to update iterator I
2829 after insertion (see enum bsi_iterator_update). */
2832 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2834 set_bb_for_stmt (t, i->bb);
2835 update_modified_stmts (t);
2836 tsi_link_after (&i->tsi, t, m);
2840 /* Remove the statement pointed to by iterator I. The iterator is updated
2841 to the next statement.
2843 When REMOVE_EH_INFO is true we remove the statement pointed to by
2844 iterator I from the EH tables. Otherwise we do not modify the EH
2847 Generally, REMOVE_EH_INFO should be true when the statement is going to
2848 be removed from the IL and not reinserted elsewhere. */
2851 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2853 tree t = bsi_stmt (*i);
2854 set_bb_for_stmt (t, NULL);
2855 delink_stmt_imm_use (t);
2856 tsi_delink (&i->tsi);
2857 mark_stmt_modified (t);
2859 remove_stmt_from_eh_region (t);
2863 /* Move the statement at FROM so it comes right after the statement at TO. */
2866 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2868 tree stmt = bsi_stmt (*from);
2869 bsi_remove (from, false);
2870 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2874 /* Move the statement at FROM so it comes right before the statement at TO. */
2877 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2879 tree stmt = bsi_stmt (*from);
2880 bsi_remove (from, false);
2881 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2885 /* Move the statement at FROM to the end of basic block BB. */
2888 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2890 block_stmt_iterator last = bsi_last (bb);
2892 /* Have to check bsi_end_p because it could be an empty block. */
2893 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2894 bsi_move_before (from, &last);
2896 bsi_move_after (from, &last);
2900 /* Replace the contents of the statement pointed to by iterator BSI
2901 with STMT. If UPDATE_EH_INFO is true, the exception handling
2902 information of the original statement is moved to the new statement. */
2906 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2909 tree orig_stmt = bsi_stmt (*bsi);
2911 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2912 set_bb_for_stmt (stmt, bsi->bb);
2914 /* Preserve EH region information from the original statement, if
2915 requested by the caller. */
2918 eh_region = lookup_stmt_eh_region (orig_stmt);
2921 remove_stmt_from_eh_region (orig_stmt);
2922 add_stmt_to_eh_region (stmt, eh_region);
2926 delink_stmt_imm_use (orig_stmt);
2927 *bsi_stmt_ptr (*bsi) = stmt;
2928 mark_stmt_modified (stmt);
2929 update_modified_stmts (stmt);
2933 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2934 is made to place the statement in an existing basic block, but
2935 sometimes that isn't possible. When it isn't possible, the edge is
2936 split and the statement is added to the new block.
2938 In all cases, the returned *BSI points to the correct location. The
2939 return value is true if insertion should be done after the location,
2940 or false if it should be done before the location. If new basic block
2941 has to be created, it is stored in *NEW_BB. */
2944 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2945 basic_block *new_bb)
2947 basic_block dest, src;
2953 /* If the destination has one predecessor which has no PHI nodes,
2954 insert there. Except for the exit block.
2956 The requirement for no PHI nodes could be relaxed. Basically we
2957 would have to examine the PHIs to prove that none of them used
2958 the value set by the statement we want to insert on E. That
2959 hardly seems worth the effort. */
2960 if (single_pred_p (dest)
2961 && ! phi_nodes (dest)
2962 && dest != EXIT_BLOCK_PTR)
2964 *bsi = bsi_start (dest);
2965 if (bsi_end_p (*bsi))
2968 /* Make sure we insert after any leading labels. */
2969 tmp = bsi_stmt (*bsi);
2970 while (TREE_CODE (tmp) == LABEL_EXPR)
2973 if (bsi_end_p (*bsi))
2975 tmp = bsi_stmt (*bsi);
2978 if (bsi_end_p (*bsi))
2980 *bsi = bsi_last (dest);
2987 /* If the source has one successor, the edge is not abnormal and
2988 the last statement does not end a basic block, insert there.
2989 Except for the entry block. */
2991 if ((e->flags & EDGE_ABNORMAL) == 0
2992 && single_succ_p (src)
2993 && src != ENTRY_BLOCK_PTR)
2995 *bsi = bsi_last (src);
2996 if (bsi_end_p (*bsi))
2999 tmp = bsi_stmt (*bsi);
3000 if (!stmt_ends_bb_p (tmp))
3003 /* Insert code just before returning the value. We may need to decompose
3004 the return in the case it contains non-trivial operand. */
3005 if (TREE_CODE (tmp) == RETURN_EXPR)
3007 tree op = TREE_OPERAND (tmp, 0);
3008 if (op && !is_gimple_val (op))
3010 gcc_assert (TREE_CODE (op) == MODIFY_EXPR);
3011 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3012 TREE_OPERAND (tmp, 0) = TREE_OPERAND (op, 0);
3019 /* Otherwise, create a new basic block, and split this edge. */
3020 dest = split_edge (e);
3023 e = single_pred_edge (dest);
3028 /* This routine will commit all pending edge insertions, creating any new
3029 basic blocks which are necessary. */
3032 bsi_commit_edge_inserts (void)
3038 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3041 FOR_EACH_EDGE (e, ei, bb->succs)
3042 bsi_commit_one_edge_insert (e, NULL);
3046 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3047 to this block, otherwise set it to NULL. */
3050 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3054 if (PENDING_STMT (e))
3056 block_stmt_iterator bsi;
3057 tree stmt = PENDING_STMT (e);
3059 PENDING_STMT (e) = NULL_TREE;
3061 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3062 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3064 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3069 /* Add STMT to the pending list of edge E. No actual insertion is
3070 made until a call to bsi_commit_edge_inserts () is made. */
3073 bsi_insert_on_edge (edge e, tree stmt)
3075 append_to_statement_list (stmt, &PENDING_STMT (e));
3078 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3079 block has to be created, it is returned. */
3082 bsi_insert_on_edge_immediate (edge e, tree stmt)
3084 block_stmt_iterator bsi;
3085 basic_block new_bb = NULL;
3087 gcc_assert (!PENDING_STMT (e));
3089 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3090 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3092 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3097 /*---------------------------------------------------------------------------
3098 Tree specific functions for CFG manipulation
3099 ---------------------------------------------------------------------------*/
3101 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3104 reinstall_phi_args (edge new_edge, edge old_edge)
3108 if (!PENDING_STMT (old_edge))
3111 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3113 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3115 tree result = TREE_PURPOSE (var);
3116 tree arg = TREE_VALUE (var);
3118 gcc_assert (result == PHI_RESULT (phi));
3120 add_phi_arg (phi, arg, new_edge);
3123 PENDING_STMT (old_edge) = NULL;
3126 /* Returns the basic block after that the new basic block created
3127 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3128 near its "logical" location. This is of most help to humans looking
3129 at debugging dumps. */
3132 split_edge_bb_loc (edge edge_in)
3134 basic_block dest = edge_in->dest;
3136 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3137 return edge_in->src;
3139 return dest->prev_bb;
3142 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3143 Abort on abnormal edges. */
3146 tree_split_edge (edge edge_in)
3148 basic_block new_bb, after_bb, dest;
3151 /* Abnormal edges cannot be split. */
3152 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3154 dest = edge_in->dest;
3156 after_bb = split_edge_bb_loc (edge_in);
3158 new_bb = create_empty_bb (after_bb);
3159 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3160 new_bb->count = edge_in->count;
3161 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3162 new_edge->probability = REG_BR_PROB_BASE;
3163 new_edge->count = edge_in->count;
3165 e = redirect_edge_and_branch (edge_in, new_bb);
3167 reinstall_phi_args (new_edge, e);
3173 /* Return true when BB has label LABEL in it. */
3176 has_label_p (basic_block bb, tree label)
3178 block_stmt_iterator bsi;
3180 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3182 tree stmt = bsi_stmt (bsi);
3184 if (TREE_CODE (stmt) != LABEL_EXPR)
3186 if (LABEL_EXPR_LABEL (stmt) == label)
3193 /* Callback for walk_tree, check that all elements with address taken are
3194 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3195 inside a PHI node. */
3198 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3201 bool in_phi = (data != NULL);
3206 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3207 #define CHECK_OP(N, MSG) \
3208 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3209 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3211 switch (TREE_CODE (t))
3214 if (SSA_NAME_IN_FREE_LIST (t))
3216 error ("SSA name in freelist but still referenced");
3222 x = fold (ASSERT_EXPR_COND (t));
3223 if (x == boolean_false_node)
3225 error ("ASSERT_EXPR with an always-false condition");
3231 x = TREE_OPERAND (t, 0);
3232 if (TREE_CODE (x) == BIT_FIELD_REF
3233 && is_gimple_reg (TREE_OPERAND (x, 0)))
3235 error ("GIMPLE register modified with BIT_FIELD_REF");
3244 bool old_side_effects;
3247 bool new_side_effects;
3249 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3250 dead PHIs that take the address of something. But if the PHI
3251 result is dead, the fact that it takes the address of anything
3252 is irrelevant. Because we can not tell from here if a PHI result
3253 is dead, we just skip this check for PHIs altogether. This means
3254 we may be missing "valid" checks, but what can you do?
3255 This was PR19217. */
3259 old_invariant = TREE_INVARIANT (t);
3260 old_constant = TREE_CONSTANT (t);
3261 old_side_effects = TREE_SIDE_EFFECTS (t);
3263 recompute_tree_invariant_for_addr_expr (t);
3264 new_invariant = TREE_INVARIANT (t);
3265 new_side_effects = TREE_SIDE_EFFECTS (t);
3266 new_constant = TREE_CONSTANT (t);
3268 if (old_invariant != new_invariant)
3270 error ("invariant not recomputed when ADDR_EXPR changed");
3274 if (old_constant != new_constant)
3276 error ("constant not recomputed when ADDR_EXPR changed");
3279 if (old_side_effects != new_side_effects)
3281 error ("side effects not recomputed when ADDR_EXPR changed");
3285 /* Skip any references (they will be checked when we recurse down the
3286 tree) and ensure that any variable used as a prefix is marked
3288 for (x = TREE_OPERAND (t, 0);
3289 handled_component_p (x);
3290 x = TREE_OPERAND (x, 0))
3293 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3295 if (!TREE_ADDRESSABLE (x))
3297 error ("address taken, but ADDRESSABLE bit not set");
3304 x = COND_EXPR_COND (t);
3305 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3307 error ("non-boolean used in condition");
3310 if (!is_gimple_condexpr (x))
3312 error ("invalid conditional operand");
3319 case FIX_TRUNC_EXPR:
3321 case FIX_FLOOR_EXPR:
3322 case FIX_ROUND_EXPR:
3327 case NON_LVALUE_EXPR:
3328 case TRUTH_NOT_EXPR:
3329 CHECK_OP (0, "invalid operand to unary operator");
3336 case ARRAY_RANGE_REF:
3338 case VIEW_CONVERT_EXPR:
3339 /* We have a nest of references. Verify that each of the operands
3340 that determine where to reference is either a constant or a variable,
3341 verify that the base is valid, and then show we've already checked
3343 while (handled_component_p (t))
3345 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3346 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3347 else if (TREE_CODE (t) == ARRAY_REF
3348 || TREE_CODE (t) == ARRAY_RANGE_REF)
3350 CHECK_OP (1, "invalid array index");
3351 if (TREE_OPERAND (t, 2))
3352 CHECK_OP (2, "invalid array lower bound");
3353 if (TREE_OPERAND (t, 3))
3354 CHECK_OP (3, "invalid array stride");
3356 else if (TREE_CODE (t) == BIT_FIELD_REF)
3358 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3359 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3362 t = TREE_OPERAND (t, 0);
3365 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3367 error ("invalid reference prefix");
3379 case UNORDERED_EXPR:
3390 case TRUNC_DIV_EXPR:
3392 case FLOOR_DIV_EXPR:
3393 case ROUND_DIV_EXPR:
3394 case TRUNC_MOD_EXPR:
3396 case FLOOR_MOD_EXPR:
3397 case ROUND_MOD_EXPR:
3399 case EXACT_DIV_EXPR:
3409 CHECK_OP (0, "invalid operand to binary operator");
3410 CHECK_OP (1, "invalid operand to binary operator");
3422 /* Verify STMT, return true if STMT is not in GIMPLE form.
3423 TODO: Implement type checking. */
3426 verify_stmt (tree stmt, bool last_in_block)
3430 if (OMP_DIRECTIVE_P (stmt))
3432 /* OpenMP directives are validated by the FE and never operated
3433 on by the optimizers. Furthermore, OMP_FOR may contain
3434 non-gimple expressions when the main index variable has had
3435 its address taken. This does not affect the loop itself
3436 because the header of an OMP_FOR is merely used to determine
3437 how to setup the parallel iteration. */
3441 if (!is_gimple_stmt (stmt))
3443 error ("is not a valid GIMPLE statement");
3447 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3450 debug_generic_stmt (addr);
3454 /* If the statement is marked as part of an EH region, then it is
3455 expected that the statement could throw. Verify that when we
3456 have optimizations that simplify statements such that we prove
3457 that they cannot throw, that we update other data structures
3459 if (lookup_stmt_eh_region (stmt) >= 0)
3461 if (!tree_could_throw_p (stmt))
3463 error ("statement marked for throw, but doesn%'t");
3466 if (!last_in_block && tree_can_throw_internal (stmt))
3468 error ("statement marked for throw in middle of block");
3476 debug_generic_stmt (stmt);
3481 /* Return true when the T can be shared. */
3484 tree_node_can_be_shared (tree t)
3486 if (IS_TYPE_OR_DECL_P (t)
3487 || is_gimple_min_invariant (t)
3488 || TREE_CODE (t) == SSA_NAME
3489 || t == error_mark_node
3490 || TREE_CODE (t) == IDENTIFIER_NODE)
3493 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3496 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3497 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3498 || TREE_CODE (t) == COMPONENT_REF
3499 || TREE_CODE (t) == REALPART_EXPR
3500 || TREE_CODE (t) == IMAGPART_EXPR)
3501 t = TREE_OPERAND (t, 0);
3510 /* Called via walk_trees. Verify tree sharing. */
3513 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3515 htab_t htab = (htab_t) data;
3518 if (tree_node_can_be_shared (*tp))
3520 *walk_subtrees = false;
3524 slot = htab_find_slot (htab, *tp, INSERT);
3526 return (tree) *slot;
3533 /* Verify the GIMPLE statement chain. */
3539 block_stmt_iterator bsi;
3544 timevar_push (TV_TREE_STMT_VERIFY);
3545 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3552 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3554 int phi_num_args = PHI_NUM_ARGS (phi);
3556 if (bb_for_stmt (phi) != bb)
3558 error ("bb_for_stmt (phi) is set to a wrong basic block");
3562 for (i = 0; i < phi_num_args; i++)
3564 tree t = PHI_ARG_DEF (phi, i);
3567 /* Addressable variables do have SSA_NAMEs but they
3568 are not considered gimple values. */
3569 if (TREE_CODE (t) != SSA_NAME
3570 && TREE_CODE (t) != FUNCTION_DECL
3571 && !is_gimple_val (t))
3573 error ("PHI def is not a GIMPLE value");
3574 debug_generic_stmt (phi);
3575 debug_generic_stmt (t);
3579 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3582 debug_generic_stmt (addr);
3586 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3589 error ("incorrect sharing of tree nodes");
3590 debug_generic_stmt (phi);
3591 debug_generic_stmt (addr);
3597 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3599 tree stmt = bsi_stmt (bsi);
3601 if (bb_for_stmt (stmt) != bb)
3603 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3608 err |= verify_stmt (stmt, bsi_end_p (bsi));
3609 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3612 error ("incorrect sharing of tree nodes");
3613 debug_generic_stmt (stmt);
3614 debug_generic_stmt (addr);
3621 internal_error ("verify_stmts failed");
3624 timevar_pop (TV_TREE_STMT_VERIFY);
3628 /* Verifies that the flow information is OK. */
3631 tree_verify_flow_info (void)
3635 block_stmt_iterator bsi;
3640 if (ENTRY_BLOCK_PTR->stmt_list)
3642 error ("ENTRY_BLOCK has a statement list associated with it");
3646 if (EXIT_BLOCK_PTR->stmt_list)
3648 error ("EXIT_BLOCK has a statement list associated with it");
3652 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3653 if (e->flags & EDGE_FALLTHRU)
3655 error ("fallthru to exit from bb %d", e->src->index);
3661 bool found_ctrl_stmt = false;
3665 /* Skip labels on the start of basic block. */
3666 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3668 tree prev_stmt = stmt;
3670 stmt = bsi_stmt (bsi);
3672 if (TREE_CODE (stmt) != LABEL_EXPR)
3675 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3677 error ("nonlocal label ");
3678 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3679 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3684 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3687 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3688 fprintf (stderr, " to block does not match in bb %d",
3693 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3694 != current_function_decl)
3697 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3698 fprintf (stderr, " has incorrect context in bb %d",
3704 /* Verify that body of basic block BB is free of control flow. */
3705 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3707 tree stmt = bsi_stmt (bsi);
3709 if (found_ctrl_stmt)
3711 error ("control flow in the middle of basic block %d",
3716 if (stmt_ends_bb_p (stmt))
3717 found_ctrl_stmt = true;
3719 if (TREE_CODE (stmt) == LABEL_EXPR)
3722 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3723 fprintf (stderr, " in the middle of basic block %d", bb->index);
3728 bsi = bsi_last (bb);
3729 if (bsi_end_p (bsi))
3732 stmt = bsi_stmt (bsi);
3734 err |= verify_eh_edges (stmt);
3736 if (is_ctrl_stmt (stmt))
3738 FOR_EACH_EDGE (e, ei, bb->succs)
3739 if (e->flags & EDGE_FALLTHRU)
3741 error ("fallthru edge after a control statement in bb %d",
3747 switch (TREE_CODE (stmt))
3753 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3754 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3756 error ("structured COND_EXPR at the end of bb %d", bb->index);
3760 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3762 if (!true_edge || !false_edge
3763 || !(true_edge->flags & EDGE_TRUE_VALUE)
3764 || !(false_edge->flags & EDGE_FALSE_VALUE)
3765 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3766 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3767 || EDGE_COUNT (bb->succs) >= 3)
3769 error ("wrong outgoing edge flags at end of bb %d",
3774 if (!has_label_p (true_edge->dest,
3775 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3777 error ("%<then%> label does not match edge at end of bb %d",
3782 if (!has_label_p (false_edge->dest,
3783 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3785 error ("%<else%> label does not match edge at end of bb %d",
3793 if (simple_goto_p (stmt))
3795 error ("explicit goto at end of bb %d", bb->index);
3800 /* FIXME. We should double check that the labels in the
3801 destination blocks have their address taken. */
3802 FOR_EACH_EDGE (e, ei, bb->succs)
3803 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3804 | EDGE_FALSE_VALUE))
3805 || !(e->flags & EDGE_ABNORMAL))
3807 error ("wrong outgoing edge flags at end of bb %d",
3815 if (!single_succ_p (bb)
3816 || (single_succ_edge (bb)->flags
3817 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3818 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3820 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3823 if (single_succ (bb) != EXIT_BLOCK_PTR)
3825 error ("return edge does not point to exit in bb %d",
3838 vec = SWITCH_LABELS (stmt);
3839 n = TREE_VEC_LENGTH (vec);
3841 /* Mark all the destination basic blocks. */
3842 for (i = 0; i < n; ++i)
3844 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3845 basic_block label_bb = label_to_block (lab);
3847 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3848 label_bb->aux = (void *)1;
3851 /* Verify that the case labels are sorted. */
3852 prev = TREE_VEC_ELT (vec, 0);
3853 for (i = 1; i < n - 1; ++i)
3855 tree c = TREE_VEC_ELT (vec, i);
3858 error ("found default case not at end of case vector");
3862 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3864 error ("case labels not sorted: ");
3865 print_generic_expr (stderr, prev, 0);
3866 fprintf (stderr," is greater than ");
3867 print_generic_expr (stderr, c, 0);
3868 fprintf (stderr," but comes before it.\n");
3873 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3875 error ("no default case found at end of case vector");
3879 FOR_EACH_EDGE (e, ei, bb->succs)
3883 error ("extra outgoing edge %d->%d",
3884 bb->index, e->dest->index);
3887 e->dest->aux = (void *)2;
3888 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3889 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3891 error ("wrong outgoing edge flags at end of bb %d",
3897 /* Check that we have all of them. */
3898 for (i = 0; i < n; ++i)
3900 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3901 basic_block label_bb = label_to_block (lab);
3903 if (label_bb->aux != (void *)2)
3905 error ("missing edge %i->%i",
3906 bb->index, label_bb->index);
3911 FOR_EACH_EDGE (e, ei, bb->succs)
3912 e->dest->aux = (void *)0;
3919 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3920 verify_dominators (CDI_DOMINATORS);
3926 /* Updates phi nodes after creating a forwarder block joined
3927 by edge FALLTHRU. */
3930 tree_make_forwarder_block (edge fallthru)
3934 basic_block dummy, bb;
3935 tree phi, new_phi, var;
3937 dummy = fallthru->src;
3938 bb = fallthru->dest;
3940 if (single_pred_p (bb))
3943 /* If we redirected a branch we must create new phi nodes at the
3945 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3947 var = PHI_RESULT (phi);
3948 new_phi = create_phi_node (var, bb);
3949 SSA_NAME_DEF_STMT (var) = new_phi;
3950 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3951 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3954 /* Ensure that the PHI node chain is in the same order. */
3955 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3957 /* Add the arguments we have stored on edges. */
3958 FOR_EACH_EDGE (e, ei, bb->preds)
3963 flush_pending_stmts (e);
3968 /* Return a non-special label in the head of basic block BLOCK.
3969 Create one if it doesn't exist. */
3972 tree_block_label (basic_block bb)
3974 block_stmt_iterator i, s = bsi_start (bb);
3978 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
3980 stmt = bsi_stmt (i);
3981 if (TREE_CODE (stmt) != LABEL_EXPR)
3983 label = LABEL_EXPR_LABEL (stmt);
3984 if (!DECL_NONLOCAL (label))
3987 bsi_move_before (&i, &s);
3992 label = create_artificial_label ();
3993 stmt = build1 (LABEL_EXPR, void_type_node, label);
3994 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
3999 /* Attempt to perform edge redirection by replacing a possibly complex
4000 jump instruction by a goto or by removing the jump completely.
4001 This can apply only if all edges now point to the same block. The
4002 parameters and return values are equivalent to
4003 redirect_edge_and_branch. */
4006 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4008 basic_block src = e->src;
4009 block_stmt_iterator b;
4012 /* We can replace or remove a complex jump only when we have exactly
4014 if (EDGE_COUNT (src->succs) != 2
4015 /* Verify that all targets will be TARGET. Specifically, the
4016 edge that is not E must also go to TARGET. */
4017 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4023 stmt = bsi_stmt (b);
4025 if (TREE_CODE (stmt) == COND_EXPR
4026 || TREE_CODE (stmt) == SWITCH_EXPR)
4028 bsi_remove (&b, true);
4029 e = ssa_redirect_edge (e, target);
4030 e->flags = EDGE_FALLTHRU;
4038 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4039 edge representing the redirected branch. */
4042 tree_redirect_edge_and_branch (edge e, basic_block dest)
4044 basic_block bb = e->src;
4045 block_stmt_iterator bsi;
4049 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
4052 if (e->src != ENTRY_BLOCK_PTR
4053 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4056 if (e->dest == dest)
4059 label = tree_block_label (dest);
4061 bsi = bsi_last (bb);
4062 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4064 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4067 stmt = (e->flags & EDGE_TRUE_VALUE
4068 ? COND_EXPR_THEN (stmt)
4069 : COND_EXPR_ELSE (stmt));
4070 GOTO_DESTINATION (stmt) = label;
4074 /* No non-abnormal edges should lead from a non-simple goto, and
4075 simple ones should be represented implicitly. */
4080 tree cases = get_cases_for_edge (e, stmt);
4082 /* If we have a list of cases associated with E, then use it
4083 as it's a lot faster than walking the entire case vector. */
4086 edge e2 = find_edge (e->src, dest);
4093 CASE_LABEL (cases) = label;
4094 cases = TREE_CHAIN (cases);
4097 /* If there was already an edge in the CFG, then we need
4098 to move all the cases associated with E to E2. */
4101 tree cases2 = get_cases_for_edge (e2, stmt);
4103 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4104 TREE_CHAIN (cases2) = first;
4109 tree vec = SWITCH_LABELS (stmt);
4110 size_t i, n = TREE_VEC_LENGTH (vec);
4112 for (i = 0; i < n; i++)
4114 tree elt = TREE_VEC_ELT (vec, i);
4116 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4117 CASE_LABEL (elt) = label;
4125 bsi_remove (&bsi, true);
4126 e->flags |= EDGE_FALLTHRU;
4130 /* Otherwise it must be a fallthru edge, and we don't need to
4131 do anything besides redirecting it. */
4132 gcc_assert (e->flags & EDGE_FALLTHRU);
4136 /* Update/insert PHI nodes as necessary. */
4138 /* Now update the edges in the CFG. */
4139 e = ssa_redirect_edge (e, dest);
4145 /* Simple wrapper, as we can always redirect fallthru edges. */
4148 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4150 e = tree_redirect_edge_and_branch (e, dest);
4157 /* Splits basic block BB after statement STMT (but at least after the
4158 labels). If STMT is NULL, BB is split just after the labels. */
4161 tree_split_block (basic_block bb, void *stmt)
4163 block_stmt_iterator bsi, bsi_tgt;
4169 new_bb = create_empty_bb (bb);
4171 /* Redirect the outgoing edges. */
4172 new_bb->succs = bb->succs;
4174 FOR_EACH_EDGE (e, ei, new_bb->succs)
4177 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4180 /* Move everything from BSI to the new basic block. */
4181 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4183 act = bsi_stmt (bsi);
4184 if (TREE_CODE (act) == LABEL_EXPR)
4197 bsi_tgt = bsi_start (new_bb);
4198 while (!bsi_end_p (bsi))
4200 act = bsi_stmt (bsi);
4201 bsi_remove (&bsi, false);
4202 bsi_insert_after (&bsi_tgt, act, BSI_NEW_STMT);
4209 /* Moves basic block BB after block AFTER. */
4212 tree_move_block_after (basic_block bb, basic_block after)
4214 if (bb->prev_bb == after)
4218 link_block (bb, after);
4224 /* Return true if basic_block can be duplicated. */
4227 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4233 /* Create a duplicate of the basic block BB. NOTE: This does not
4234 preserve SSA form. */
4237 tree_duplicate_bb (basic_block bb)
4240 block_stmt_iterator bsi, bsi_tgt;
4243 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4245 /* Copy the PHI nodes. We ignore PHI node arguments here because
4246 the incoming edges have not been setup yet. */
4247 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4249 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4250 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4253 /* Keep the chain of PHI nodes in the same order so that they can be
4254 updated by ssa_redirect_edge. */
4255 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4257 bsi_tgt = bsi_start (new_bb);
4258 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4260 def_operand_p def_p;
4261 ssa_op_iter op_iter;
4265 stmt = bsi_stmt (bsi);
4266 if (TREE_CODE (stmt) == LABEL_EXPR)
4269 /* Create a new copy of STMT and duplicate STMT's virtual
4271 copy = unshare_expr (stmt);
4272 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4273 copy_virtual_operands (copy, stmt);
4274 region = lookup_stmt_eh_region (stmt);
4276 add_stmt_to_eh_region (copy, region);
4278 /* Create new names for all the definitions created by COPY and
4279 add replacement mappings for each new name. */
4280 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4281 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4288 /* Basic block BB_COPY was created by code duplication. Add phi node
4289 arguments for edges going out of BB_COPY. The blocks that were
4290 duplicated have BB_DUPLICATED set. */
4293 add_phi_args_after_copy_bb (basic_block bb_copy)
4295 basic_block bb, dest;
4298 tree phi, phi_copy, phi_next, def;
4300 bb = get_bb_original (bb_copy);
4302 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4304 if (!phi_nodes (e_copy->dest))
4307 if (e_copy->dest->flags & BB_DUPLICATED)
4308 dest = get_bb_original (e_copy->dest);
4310 dest = e_copy->dest;
4312 e = find_edge (bb, dest);
4315 /* During loop unrolling the target of the latch edge is copied.
4316 In this case we are not looking for edge to dest, but to
4317 duplicated block whose original was dest. */
4318 FOR_EACH_EDGE (e, ei, bb->succs)
4319 if ((e->dest->flags & BB_DUPLICATED)
4320 && get_bb_original (e->dest) == dest)
4323 gcc_assert (e != NULL);
4326 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4328 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4330 phi_next = PHI_CHAIN (phi);
4331 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4332 add_phi_arg (phi_copy, def, e_copy);
4337 /* Blocks in REGION_COPY array of length N_REGION were created by
4338 duplication of basic blocks. Add phi node arguments for edges
4339 going from these blocks. */
4342 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4346 for (i = 0; i < n_region; i++)
4347 region_copy[i]->flags |= BB_DUPLICATED;
4349 for (i = 0; i < n_region; i++)
4350 add_phi_args_after_copy_bb (region_copy[i]);
4352 for (i = 0; i < n_region; i++)
4353 region_copy[i]->flags &= ~BB_DUPLICATED;
4356 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4357 important exit edge EXIT. By important we mean that no SSA name defined
4358 inside region is live over the other exit edges of the region. All entry
4359 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4360 to the duplicate of the region. SSA form, dominance and loop information
4361 is updated. The new basic blocks are stored to REGION_COPY in the same
4362 order as they had in REGION, provided that REGION_COPY is not NULL.
4363 The function returns false if it is unable to copy the region,
4367 tree_duplicate_sese_region (edge entry, edge exit,
4368 basic_block *region, unsigned n_region,
4369 basic_block *region_copy)
4372 bool free_region_copy = false, copying_header = false;
4373 struct loop *loop = entry->dest->loop_father;
4377 int total_freq = 0, entry_freq = 0;
4378 gcov_type total_count = 0, entry_count = 0;
4380 if (!can_copy_bbs_p (region, n_region))
4383 /* Some sanity checking. Note that we do not check for all possible
4384 missuses of the functions. I.e. if you ask to copy something weird,
4385 it will work, but the state of structures probably will not be
4387 for (i = 0; i < n_region; i++)
4389 /* We do not handle subloops, i.e. all the blocks must belong to the
4391 if (region[i]->loop_father != loop)
4394 if (region[i] != entry->dest
4395 && region[i] == loop->header)
4401 /* In case the function is used for loop header copying (which is the primary
4402 use), ensure that EXIT and its copy will be new latch and entry edges. */
4403 if (loop->header == entry->dest)
4405 copying_header = true;
4406 loop->copy = loop->outer;
4408 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4411 for (i = 0; i < n_region; i++)
4412 if (region[i] != exit->src
4413 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4419 region_copy = XNEWVEC (basic_block, n_region);
4420 free_region_copy = true;
4423 gcc_assert (!need_ssa_update_p ());
4425 /* Record blocks outside the region that are dominated by something
4427 doms = XNEWVEC (basic_block, n_basic_blocks);
4428 initialize_original_copy_tables ();
4430 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4432 if (entry->dest->count)
4434 total_count = entry->dest->count;
4435 entry_count = entry->count;
4436 /* Fix up corner cases, to avoid division by zero or creation of negative
4438 if (entry_count > total_count)
4439 entry_count = total_count;
4443 total_freq = entry->dest->frequency;
4444 entry_freq = EDGE_FREQUENCY (entry);
4445 /* Fix up corner cases, to avoid division by zero or creation of negative
4447 if (total_freq == 0)
4449 else if (entry_freq > total_freq)
4450 entry_freq = total_freq;
4453 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4454 split_edge_bb_loc (entry));
4457 scale_bbs_frequencies_gcov_type (region, n_region,
4458 total_count - entry_count,
4460 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4465 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4467 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4472 loop->header = exit->dest;
4473 loop->latch = exit->src;
4476 /* Redirect the entry and add the phi node arguments. */
4477 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4478 gcc_assert (redirected != NULL);
4479 flush_pending_stmts (entry);
4481 /* Concerning updating of dominators: We must recount dominators
4482 for entry block and its copy. Anything that is outside of the
4483 region, but was dominated by something inside needs recounting as
4485 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4486 doms[n_doms++] = get_bb_original (entry->dest);
4487 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4490 /* Add the other PHI node arguments. */
4491 add_phi_args_after_copy (region_copy, n_region);
4493 /* Update the SSA web. */
4494 update_ssa (TODO_update_ssa);
4496 if (free_region_copy)
4499 free_original_copy_tables ();
4504 DEF_VEC_P(basic_block);
4505 DEF_VEC_ALLOC_P(basic_block,heap);
4508 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4509 adding blocks when the dominator traversal reaches EXIT. This
4510 function silently assumes that ENTRY strictly dominates EXIT. */
4513 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4514 VEC(basic_block,heap) **bbs_p)
4518 for (son = first_dom_son (CDI_DOMINATORS, entry);
4520 son = next_dom_son (CDI_DOMINATORS, son))
4522 VEC_safe_push (basic_block, heap, *bbs_p, son);
4524 gather_blocks_in_sese_region (son, exit, bbs_p);
4534 bitmap vars_to_remove;
4535 htab_t new_label_map;
4539 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4540 contained in *TP and change the DECL_CONTEXT of every local
4541 variable referenced in *TP. */
4544 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4546 struct move_stmt_d *p = (struct move_stmt_d *) data;
4549 if (p->block && IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t))))
4550 TREE_BLOCK (t) = p->block;
4552 if (OMP_DIRECTIVE_P (t)
4553 && TREE_CODE (t) != OMP_RETURN
4554 && TREE_CODE (t) != OMP_CONTINUE)
4556 /* Do not remap variables inside OMP directives. Variables
4557 referenced in clauses and directive header belong to the
4558 parent function and should not be moved into the child
4560 bool save_remap_decls_p = p->remap_decls_p;
4561 p->remap_decls_p = false;
4564 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4566 p->remap_decls_p = save_remap_decls_p;
4568 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4570 if (TREE_CODE (t) == LABEL_DECL)
4572 if (p->new_label_map)
4574 struct tree_map in, *out;
4576 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4581 DECL_CONTEXT (t) = p->to_context;
4583 else if (p->remap_decls_p)
4585 DECL_CONTEXT (t) = p->to_context;
4587 if (TREE_CODE (t) == VAR_DECL)
4589 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4590 f->unexpanded_var_list
4591 = tree_cons (0, t, f->unexpanded_var_list);
4593 /* Mark T to be removed from the original function,
4594 otherwise it will be given a DECL_RTL when the
4595 original function is expanded. */
4596 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4600 else if (TYPE_P (t))
4607 /* Move basic block BB from function CFUN to function DEST_FN. The
4608 block is moved out of the original linked list and placed after
4609 block AFTER in the new list. Also, the block is removed from the
4610 original array of blocks and placed in DEST_FN's array of blocks.
4611 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4612 updated to reflect the moved edges.
4614 On exit, local variables that need to be removed from
4615 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4618 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4619 basic_block after, bool update_edge_count_p,
4620 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4622 struct control_flow_graph *cfg;
4625 block_stmt_iterator si;
4626 struct move_stmt_d d;
4627 unsigned old_len, new_len;
4630 /* Link BB to the new linked list. */
4631 move_block_after (bb, after);
4633 /* Update the edge count in the corresponding flowgraphs. */
4634 if (update_edge_count_p)
4635 FOR_EACH_EDGE (e, ei, bb->succs)
4637 cfun->cfg->x_n_edges--;
4638 dest_cfun->cfg->x_n_edges++;
4641 /* Remove BB from the original basic block array. */
4642 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4643 cfun->cfg->x_n_basic_blocks--;
4645 /* Grow DEST_CFUN's basic block array if needed. */
4646 cfg = dest_cfun->cfg;
4647 cfg->x_n_basic_blocks++;
4648 if (bb->index > cfg->x_last_basic_block)
4649 cfg->x_last_basic_block = bb->index;
4651 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4652 if ((unsigned) cfg->x_last_basic_block >= old_len)
4654 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4655 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4656 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4657 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4660 VEC_replace (basic_block, cfg->x_basic_block_info,
4661 cfg->x_last_basic_block, bb);
4663 /* The statements in BB need to be associated with a new TREE_BLOCK.
4664 Labels need to be associated with a new label-to-block map. */
4665 memset (&d, 0, sizeof (d));
4666 d.vars_to_remove = vars_to_remove;
4668 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4670 tree stmt = bsi_stmt (si);
4673 d.from_context = cfun->decl;
4674 d.to_context = dest_cfun->decl;
4675 d.remap_decls_p = true;
4676 d.new_label_map = new_label_map;
4677 if (TREE_BLOCK (stmt))
4678 d.block = DECL_INITIAL (dest_cfun->decl);
4680 walk_tree (&stmt, move_stmt_r, &d, NULL);
4682 if (TREE_CODE (stmt) == LABEL_EXPR)
4684 tree label = LABEL_EXPR_LABEL (stmt);
4685 int uid = LABEL_DECL_UID (label);
4687 gcc_assert (uid > -1);
4689 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4690 if (old_len <= (unsigned) uid)
4692 new_len = 3 * uid / 2;
4693 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4695 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4696 memset (&addr[old_len], 0,
4697 sizeof (basic_block) * (new_len - old_len));
4700 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4701 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4703 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4705 if (uid >= dest_cfun->last_label_uid)
4706 dest_cfun->last_label_uid = uid + 1;
4708 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4709 TREE_OPERAND (stmt, 0) =
4710 build_int_cst (NULL_TREE,
4711 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4714 region = lookup_stmt_eh_region (stmt);
4717 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4718 remove_stmt_from_eh_region (stmt);
4723 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4724 the outermost EH region. Use REGION as the incoming base EH region. */
4727 find_outermost_region_in_block (struct function *src_cfun,
4728 basic_block bb, int region)
4730 block_stmt_iterator si;
4732 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4734 tree stmt = bsi_stmt (si);
4737 if (TREE_CODE (stmt) == RESX_EXPR)
4738 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4740 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4741 if (stmt_region > 0)
4744 region = stmt_region;
4745 else if (stmt_region != region)
4747 region = eh_region_outermost (src_cfun, stmt_region, region);
4748 gcc_assert (region != -1);
4757 new_label_mapper (tree decl, void *data)
4759 htab_t hash = (htab_t) data;
4763 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4765 m = xmalloc (sizeof (struct tree_map));
4766 m->hash = DECL_UID (decl);
4768 m->to = create_artificial_label ();
4769 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4771 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4772 gcc_assert (*slot == NULL);
4779 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4780 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4781 single basic block in the original CFG and the new basic block is
4782 returned. DEST_CFUN must not have a CFG yet.
4784 Note that the region need not be a pure SESE region. Blocks inside
4785 the region may contain calls to abort/exit. The only restriction
4786 is that ENTRY_BB should be the only entry point and it must
4789 All local variables referenced in the region are assumed to be in
4790 the corresponding BLOCK_VARS and unexpanded variable lists
4791 associated with DEST_CFUN. */
4794 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4795 basic_block exit_bb)
4797 VEC(basic_block,heap) *bbs;
4798 basic_block after, bb, *entry_pred, *exit_succ;
4799 struct function *saved_cfun;
4800 int *entry_flag, *exit_flag, eh_offset;
4801 unsigned i, num_entry_edges, num_exit_edges;
4804 bitmap vars_to_remove;
4805 htab_t new_label_map;
4809 /* Collect all the blocks in the region. Manually add ENTRY_BB
4810 because it won't be added by dfs_enumerate_from. */
4811 calculate_dominance_info (CDI_DOMINATORS);
4813 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4815 gcc_assert (entry_bb != exit_bb
4817 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4820 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4821 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4823 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4824 the predecessor edges to ENTRY_BB and the successor edges to
4825 EXIT_BB so that we can re-attach them to the new basic block that
4826 will replace the region. */
4827 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4828 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4829 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4831 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4833 entry_flag[i] = e->flags;
4834 entry_pred[i++] = e->src;
4840 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4841 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4842 sizeof (basic_block));
4843 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4845 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4847 exit_flag[i] = e->flags;
4848 exit_succ[i++] = e->dest;
4859 /* Switch context to the child function to initialize DEST_FN's CFG. */
4860 gcc_assert (dest_cfun->cfg == NULL);
4863 init_empty_tree_cfg ();
4865 /* Initialize EH information for the new function. */
4867 new_label_map = NULL;
4872 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4873 region = find_outermost_region_in_block (saved_cfun, bb, region);
4875 init_eh_for_function ();
4878 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4879 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4880 new_label_map, region, 0);
4886 /* Move blocks from BBS into DEST_CFUN. */
4887 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4888 after = dest_cfun->cfg->x_entry_block_ptr;
4889 vars_to_remove = BITMAP_ALLOC (NULL);
4890 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4892 /* No need to update edge counts on the last block. It has
4893 already been updated earlier when we detached the region from
4894 the original CFG. */
4895 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4896 new_label_map, eh_offset);
4901 htab_delete (new_label_map);
4903 /* Remove the variables marked in VARS_TO_REMOVE from
4904 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4905 DECL_RTL in the context of CFUN. */
4906 if (!bitmap_empty_p (vars_to_remove))
4910 for (p = &cfun->unexpanded_var_list; *p; )
4912 tree var = TREE_VALUE (*p);
4913 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4915 *p = TREE_CHAIN (*p);
4919 p = &TREE_CHAIN (*p);
4923 BITMAP_FREE (vars_to_remove);
4925 /* Rewire the entry and exit blocks. The successor to the entry
4926 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4927 the child function. Similarly, the predecessor of DEST_FN's
4928 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4929 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4930 various CFG manipulation function get to the right CFG.
4932 FIXME, this is silly. The CFG ought to become a parameter to
4935 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4937 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4940 /* Back in the original function, the SESE region has disappeared,
4941 create a new basic block in its place. */
4942 bb = create_empty_bb (entry_pred[0]);
4943 for (i = 0; i < num_entry_edges; i++)
4944 make_edge (entry_pred[i], bb, entry_flag[i]);
4946 for (i = 0; i < num_exit_edges; i++)
4947 make_edge (bb, exit_succ[i], exit_flag[i]);
4956 free_dominance_info (CDI_DOMINATORS);
4957 free_dominance_info (CDI_POST_DOMINATORS);
4958 VEC_free (basic_block, heap, bbs);
4964 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4967 dump_function_to_file (tree fn, FILE *file, int flags)
4969 tree arg, vars, var;
4970 bool ignore_topmost_bind = false, any_var = false;
4973 struct function *saved_cfun;
4975 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
4977 arg = DECL_ARGUMENTS (fn);
4980 print_generic_expr (file, arg, dump_flags);
4981 if (TREE_CHAIN (arg))
4982 fprintf (file, ", ");
4983 arg = TREE_CHAIN (arg);
4985 fprintf (file, ")\n");
4987 if (flags & TDF_DETAILS)
4988 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
4989 if (flags & TDF_RAW)
4991 dump_node (fn, TDF_SLIM | flags, file);
4995 /* Switch CFUN to point to FN. */
4997 cfun = DECL_STRUCT_FUNCTION (fn);
4999 /* When GIMPLE is lowered, the variables are no longer available in
5000 BIND_EXPRs, so display them separately. */
5001 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5003 ignore_topmost_bind = true;
5005 fprintf (file, "{\n");
5006 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5008 var = TREE_VALUE (vars);
5010 print_generic_decl (file, var, flags);
5011 fprintf (file, "\n");
5017 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5019 /* Make a CFG based dump. */
5020 check_bb_profile (ENTRY_BLOCK_PTR, file);
5021 if (!ignore_topmost_bind)
5022 fprintf (file, "{\n");
5024 if (any_var && n_basic_blocks)
5025 fprintf (file, "\n");
5028 dump_generic_bb (file, bb, 2, flags);
5030 fprintf (file, "}\n");
5031 check_bb_profile (EXIT_BLOCK_PTR, file);
5037 /* Make a tree based dump. */
5038 chain = DECL_SAVED_TREE (fn);
5040 if (chain && TREE_CODE (chain) == BIND_EXPR)
5042 if (ignore_topmost_bind)
5044 chain = BIND_EXPR_BODY (chain);
5052 if (!ignore_topmost_bind)
5053 fprintf (file, "{\n");
5058 fprintf (file, "\n");
5060 print_generic_stmt_indented (file, chain, flags, indent);
5061 if (ignore_topmost_bind)
5062 fprintf (file, "}\n");
5065 fprintf (file, "\n\n");
5072 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5075 debug_function (tree fn, int flags)
5077 dump_function_to_file (fn, stderr, flags);
5081 /* Pretty print of the loops intermediate representation. */
5082 static void print_loop (FILE *, struct loop *, int);
5083 static void print_pred_bbs (FILE *, basic_block bb);
5084 static void print_succ_bbs (FILE *, basic_block bb);
5087 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5090 print_pred_bbs (FILE *file, basic_block bb)
5095 FOR_EACH_EDGE (e, ei, bb->preds)
5096 fprintf (file, "bb_%d ", e->src->index);
5100 /* Print on FILE the indexes for the successors of basic_block BB. */
5103 print_succ_bbs (FILE *file, basic_block bb)
5108 FOR_EACH_EDGE (e, ei, bb->succs)
5109 fprintf (file, "bb_%d ", e->dest->index);
5113 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5116 print_loop (FILE *file, struct loop *loop, int indent)
5124 s_indent = (char *) alloca ((size_t) indent + 1);
5125 memset ((void *) s_indent, ' ', (size_t) indent);
5126 s_indent[indent] = '\0';
5128 /* Print the loop's header. */
5129 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5131 /* Print the loop's body. */
5132 fprintf (file, "%s{\n", s_indent);
5134 if (bb->loop_father == loop)
5136 /* Print the basic_block's header. */
5137 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5138 print_pred_bbs (file, bb);
5139 fprintf (file, "}, succs = {");
5140 print_succ_bbs (file, bb);
5141 fprintf (file, "})\n");
5143 /* Print the basic_block's body. */
5144 fprintf (file, "%s {\n", s_indent);
5145 tree_dump_bb (bb, file, indent + 4);
5146 fprintf (file, "%s }\n", s_indent);
5149 print_loop (file, loop->inner, indent + 2);
5150 fprintf (file, "%s}\n", s_indent);
5151 print_loop (file, loop->next, indent);
5155 /* Follow a CFG edge from the entry point of the program, and on entry
5156 of a loop, pretty print the loop structure on FILE. */
5159 print_loop_ir (FILE *file)
5163 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5164 if (bb && bb->loop_father)
5165 print_loop (file, bb->loop_father, 0);
5169 /* Debugging loops structure at tree level. */
5172 debug_loop_ir (void)
5174 print_loop_ir (stderr);
5178 /* Return true if BB ends with a call, possibly followed by some
5179 instructions that must stay with the call. Return false,
5183 tree_block_ends_with_call_p (basic_block bb)
5185 block_stmt_iterator bsi = bsi_last (bb);
5186 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5190 /* Return true if BB ends with a conditional branch. Return false,
5194 tree_block_ends_with_condjump_p (basic_block bb)
5196 tree stmt = last_stmt (bb);
5197 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5201 /* Return true if we need to add fake edge to exit at statement T.
5202 Helper function for tree_flow_call_edges_add. */
5205 need_fake_edge_p (tree t)
5209 /* NORETURN and LONGJMP calls already have an edge to exit.
5210 CONST and PURE calls do not need one.
5211 We don't currently check for CONST and PURE here, although
5212 it would be a good idea, because those attributes are
5213 figured out from the RTL in mark_constant_function, and
5214 the counter incrementation code from -fprofile-arcs
5215 leads to different results from -fbranch-probabilities. */
5216 call = get_call_expr_in (t);
5218 && !(call_expr_flags (call) & ECF_NORETURN))
5221 if (TREE_CODE (t) == ASM_EXPR
5222 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5229 /* Add fake edges to the function exit for any non constant and non
5230 noreturn calls, volatile inline assembly in the bitmap of blocks
5231 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5232 the number of blocks that were split.
5234 The goal is to expose cases in which entering a basic block does
5235 not imply that all subsequent instructions must be executed. */
5238 tree_flow_call_edges_add (sbitmap blocks)
5241 int blocks_split = 0;
5242 int last_bb = last_basic_block;
5243 bool check_last_block = false;
5245 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5249 check_last_block = true;
5251 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5253 /* In the last basic block, before epilogue generation, there will be
5254 a fallthru edge to EXIT. Special care is required if the last insn
5255 of the last basic block is a call because make_edge folds duplicate
5256 edges, which would result in the fallthru edge also being marked
5257 fake, which would result in the fallthru edge being removed by
5258 remove_fake_edges, which would result in an invalid CFG.
5260 Moreover, we can't elide the outgoing fake edge, since the block
5261 profiler needs to take this into account in order to solve the minimal
5262 spanning tree in the case that the call doesn't return.
5264 Handle this by adding a dummy instruction in a new last basic block. */
5265 if (check_last_block)
5267 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5268 block_stmt_iterator bsi = bsi_last (bb);
5270 if (!bsi_end_p (bsi))
5273 if (t && need_fake_edge_p (t))
5277 e = find_edge (bb, EXIT_BLOCK_PTR);
5280 bsi_insert_on_edge (e, build_empty_stmt ());
5281 bsi_commit_edge_inserts ();
5286 /* Now add fake edges to the function exit for any non constant
5287 calls since there is no way that we can determine if they will
5289 for (i = 0; i < last_bb; i++)
5291 basic_block bb = BASIC_BLOCK (i);
5292 block_stmt_iterator bsi;
5293 tree stmt, last_stmt;
5298 if (blocks && !TEST_BIT (blocks, i))
5301 bsi = bsi_last (bb);
5302 if (!bsi_end_p (bsi))
5304 last_stmt = bsi_stmt (bsi);
5307 stmt = bsi_stmt (bsi);
5308 if (need_fake_edge_p (stmt))
5311 /* The handling above of the final block before the
5312 epilogue should be enough to verify that there is
5313 no edge to the exit block in CFG already.
5314 Calling make_edge in such case would cause us to
5315 mark that edge as fake and remove it later. */
5316 #ifdef ENABLE_CHECKING
5317 if (stmt == last_stmt)
5319 e = find_edge (bb, EXIT_BLOCK_PTR);
5320 gcc_assert (e == NULL);
5324 /* Note that the following may create a new basic block
5325 and renumber the existing basic blocks. */
5326 if (stmt != last_stmt)
5328 e = split_block (bb, stmt);
5332 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5336 while (!bsi_end_p (bsi));
5341 verify_flow_info ();
5343 return blocks_split;
5347 tree_purge_dead_eh_edges (basic_block bb)
5349 bool changed = false;
5352 tree stmt = last_stmt (bb);
5354 if (stmt && tree_can_throw_internal (stmt))
5357 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5359 if (e->flags & EDGE_EH)
5368 /* Removal of dead EH edges might change dominators of not
5369 just immediate successors. E.g. when bb1 is changed so that
5370 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5371 eh edges purged by this function in:
5383 idom(bb5) must be recomputed. For now just free the dominance
5386 free_dominance_info (CDI_DOMINATORS);
5392 tree_purge_all_dead_eh_edges (bitmap blocks)
5394 bool changed = false;
5398 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5400 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5406 /* This function is called whenever a new edge is created or
5410 tree_execute_on_growing_pred (edge e)
5412 basic_block bb = e->dest;
5415 reserve_phi_args_for_new_edge (bb);
5418 /* This function is called immediately before edge E is removed from
5419 the edge vector E->dest->preds. */
5422 tree_execute_on_shrinking_pred (edge e)
5424 if (phi_nodes (e->dest))
5425 remove_phi_args (e);
5428 /*---------------------------------------------------------------------------
5429 Helper functions for Loop versioning
5430 ---------------------------------------------------------------------------*/
5432 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5433 of 'first'. Both of them are dominated by 'new_head' basic block. When
5434 'new_head' was created by 'second's incoming edge it received phi arguments
5435 on the edge by split_edge(). Later, additional edge 'e' was created to
5436 connect 'new_head' and 'first'. Now this routine adds phi args on this
5437 additional edge 'e' that new_head to second edge received as part of edge
5442 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5443 basic_block new_head, edge e)
5446 edge e2 = find_edge (new_head, second);
5448 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5449 edge, we should always have an edge from NEW_HEAD to SECOND. */
5450 gcc_assert (e2 != NULL);
5452 /* Browse all 'second' basic block phi nodes and add phi args to
5453 edge 'e' for 'first' head. PHI args are always in correct order. */
5455 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5457 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5459 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5460 add_phi_arg (phi1, def, e);
5464 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5465 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5466 the destination of the ELSE part. */
5468 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5469 basic_block cond_bb, void *cond_e)
5471 block_stmt_iterator bsi;
5472 tree goto1 = NULL_TREE;
5473 tree goto2 = NULL_TREE;
5474 tree new_cond_expr = NULL_TREE;
5475 tree cond_expr = (tree) cond_e;
5478 /* Build new conditional expr */
5479 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5480 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5481 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5483 /* Add new cond in cond_bb. */
5484 bsi = bsi_start (cond_bb);
5485 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5486 /* Adjust edges appropriately to connect new head with first head
5487 as well as second head. */
5488 e0 = single_succ_edge (cond_bb);
5489 e0->flags &= ~EDGE_FALLTHRU;
5490 e0->flags |= EDGE_FALSE_VALUE;
5493 struct cfg_hooks tree_cfg_hooks = {
5495 tree_verify_flow_info,
5496 tree_dump_bb, /* dump_bb */
5497 create_bb, /* create_basic_block */
5498 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5499 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5500 remove_bb, /* delete_basic_block */
5501 tree_split_block, /* split_block */
5502 tree_move_block_after, /* move_block_after */
5503 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5504 tree_merge_blocks, /* merge_blocks */
5505 tree_predict_edge, /* predict_edge */
5506 tree_predicted_by_p, /* predicted_by_p */
5507 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5508 tree_duplicate_bb, /* duplicate_block */
5509 tree_split_edge, /* split_edge */
5510 tree_make_forwarder_block, /* make_forward_block */
5511 NULL, /* tidy_fallthru_edge */
5512 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5513 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5514 tree_flow_call_edges_add, /* flow_call_edges_add */
5515 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5516 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5517 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5518 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5519 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5520 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5521 flush_pending_stmts /* flush_pending_stmts */
5525 /* Split all critical edges. */
5528 split_critical_edges (void)
5534 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5535 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5536 mappings around the calls to split_edge. */
5537 start_recording_case_labels ();
5540 FOR_EACH_EDGE (e, ei, bb->succs)
5541 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5546 end_recording_case_labels ();
5550 struct tree_opt_pass pass_split_crit_edges =
5552 "crited", /* name */
5554 split_critical_edges, /* execute */
5557 0, /* static_pass_number */
5558 TV_TREE_SPLIT_EDGES, /* tv_id */
5559 PROP_cfg, /* properties required */
5560 PROP_no_crit_edges, /* properties_provided */
5561 0, /* properties_destroyed */
5562 0, /* todo_flags_start */
5563 TODO_dump_func, /* todo_flags_finish */
5568 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5569 a temporary, make sure and register it to be renamed if necessary,
5570 and finally return the temporary. Put the statements to compute
5571 EXP before the current statement in BSI. */
5574 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5576 tree t, new_stmt, orig_stmt;
5578 if (is_gimple_val (exp))
5581 t = make_rename_temp (type, NULL);
5582 new_stmt = build2 (MODIFY_EXPR, type, t, exp);
5584 orig_stmt = bsi_stmt (*bsi);
5585 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5586 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5588 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5593 /* Build a ternary operation and gimplify it. Emit code before BSI.
5594 Return the gimple_val holding the result. */
5597 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5598 tree type, tree a, tree b, tree c)
5602 ret = fold_build3 (code, type, a, b, c);
5605 return gimplify_val (bsi, type, ret);
5608 /* Build a binary operation and gimplify it. Emit code before BSI.
5609 Return the gimple_val holding the result. */
5612 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5613 tree type, tree a, tree b)
5617 ret = fold_build2 (code, type, a, b);
5620 return gimplify_val (bsi, type, ret);
5623 /* Build a unary operation and gimplify it. Emit code before BSI.
5624 Return the gimple_val holding the result. */
5627 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5632 ret = fold_build1 (code, type, a);
5635 return gimplify_val (bsi, type, ret);
5640 /* Emit return warnings. */
5643 execute_warn_function_return (void)
5645 #ifdef USE_MAPPED_LOCATION
5646 source_location location;
5654 /* If we have a path to EXIT, then we do return. */
5655 if (TREE_THIS_VOLATILE (cfun->decl)
5656 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5658 #ifdef USE_MAPPED_LOCATION
5659 location = UNKNOWN_LOCATION;
5663 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5665 last = last_stmt (e->src);
5666 if (TREE_CODE (last) == RETURN_EXPR
5667 #ifdef USE_MAPPED_LOCATION
5668 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5670 && (locus = EXPR_LOCUS (last)) != NULL)
5674 #ifdef USE_MAPPED_LOCATION
5675 if (location == UNKNOWN_LOCATION)
5676 location = cfun->function_end_locus;
5677 warning (0, "%H%<noreturn%> function does return", &location);
5680 locus = &cfun->function_end_locus;
5681 warning (0, "%H%<noreturn%> function does return", locus);
5685 /* If we see "return;" in some basic block, then we do reach the end
5686 without returning a value. */
5687 else if (warn_return_type
5688 && !TREE_NO_WARNING (cfun->decl)
5689 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5690 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5692 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5694 tree last = last_stmt (e->src);
5695 if (TREE_CODE (last) == RETURN_EXPR
5696 && TREE_OPERAND (last, 0) == NULL
5697 && !TREE_NO_WARNING (last))
5699 #ifdef USE_MAPPED_LOCATION
5700 location = EXPR_LOCATION (last);
5701 if (location == UNKNOWN_LOCATION)
5702 location = cfun->function_end_locus;
5703 warning (0, "%Hcontrol reaches end of non-void function", &location);
5705 locus = EXPR_LOCUS (last);
5707 locus = &cfun->function_end_locus;
5708 warning (0, "%Hcontrol reaches end of non-void function", locus);
5710 TREE_NO_WARNING (cfun->decl) = 1;
5719 /* Given a basic block B which ends with a conditional and has
5720 precisely two successors, determine which of the edges is taken if
5721 the conditional is true and which is taken if the conditional is
5722 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5725 extract_true_false_edges_from_block (basic_block b,
5729 edge e = EDGE_SUCC (b, 0);
5731 if (e->flags & EDGE_TRUE_VALUE)
5734 *false_edge = EDGE_SUCC (b, 1);
5739 *true_edge = EDGE_SUCC (b, 1);
5743 struct tree_opt_pass pass_warn_function_return =
5747 execute_warn_function_return, /* execute */
5750 0, /* static_pass_number */
5752 PROP_cfg, /* properties_required */
5753 0, /* properties_provided */
5754 0, /* properties_destroyed */
5755 0, /* todo_flags_start */
5756 0, /* todo_flags_finish */
5760 /* Emit noreturn warnings. */
5763 execute_warn_function_noreturn (void)
5765 if (warn_missing_noreturn
5766 && !TREE_THIS_VOLATILE (cfun->decl)
5767 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5768 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5769 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5770 "for attribute %<noreturn%>",
5775 struct tree_opt_pass pass_warn_function_noreturn =
5779 execute_warn_function_noreturn, /* execute */
5782 0, /* static_pass_number */
5784 PROP_cfg, /* properties_required */
5785 0, /* properties_provided */
5786 0, /* properties_destroyed */
5787 0, /* todo_flags_start */
5788 0, /* todo_flags_finish */