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, src;
3151 /* Abnormal edges cannot be split. */
3152 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3155 dest = edge_in->dest;
3157 after_bb = split_edge_bb_loc (edge_in);
3159 new_bb = create_empty_bb (after_bb);
3160 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3161 new_bb->count = edge_in->count;
3162 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3163 new_edge->probability = REG_BR_PROB_BASE;
3164 new_edge->count = edge_in->count;
3166 e = redirect_edge_and_branch (edge_in, new_bb);
3168 reinstall_phi_args (new_edge, e);
3174 /* Return true when BB has label LABEL in it. */
3177 has_label_p (basic_block bb, tree label)
3179 block_stmt_iterator bsi;
3181 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3183 tree stmt = bsi_stmt (bsi);
3185 if (TREE_CODE (stmt) != LABEL_EXPR)
3187 if (LABEL_EXPR_LABEL (stmt) == label)
3194 /* Callback for walk_tree, check that all elements with address taken are
3195 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3196 inside a PHI node. */
3199 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3202 bool in_phi = (data != NULL);
3207 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3208 #define CHECK_OP(N, MSG) \
3209 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3210 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3212 switch (TREE_CODE (t))
3215 if (SSA_NAME_IN_FREE_LIST (t))
3217 error ("SSA name in freelist but still referenced");
3223 x = fold (ASSERT_EXPR_COND (t));
3224 if (x == boolean_false_node)
3226 error ("ASSERT_EXPR with an always-false condition");
3232 x = TREE_OPERAND (t, 0);
3233 if (TREE_CODE (x) == BIT_FIELD_REF
3234 && is_gimple_reg (TREE_OPERAND (x, 0)))
3236 error ("GIMPLE register modified with BIT_FIELD_REF");
3245 bool old_side_effects;
3248 bool new_side_effects;
3250 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3251 dead PHIs that take the address of something. But if the PHI
3252 result is dead, the fact that it takes the address of anything
3253 is irrelevant. Because we can not tell from here if a PHI result
3254 is dead, we just skip this check for PHIs altogether. This means
3255 we may be missing "valid" checks, but what can you do?
3256 This was PR19217. */
3260 old_invariant = TREE_INVARIANT (t);
3261 old_constant = TREE_CONSTANT (t);
3262 old_side_effects = TREE_SIDE_EFFECTS (t);
3264 recompute_tree_invariant_for_addr_expr (t);
3265 new_invariant = TREE_INVARIANT (t);
3266 new_side_effects = TREE_SIDE_EFFECTS (t);
3267 new_constant = TREE_CONSTANT (t);
3269 if (old_invariant != new_invariant)
3271 error ("invariant not recomputed when ADDR_EXPR changed");
3275 if (old_constant != new_constant)
3277 error ("constant not recomputed when ADDR_EXPR changed");
3280 if (old_side_effects != new_side_effects)
3282 error ("side effects not recomputed when ADDR_EXPR changed");
3286 /* Skip any references (they will be checked when we recurse down the
3287 tree) and ensure that any variable used as a prefix is marked
3289 for (x = TREE_OPERAND (t, 0);
3290 handled_component_p (x);
3291 x = TREE_OPERAND (x, 0))
3294 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3296 if (!TREE_ADDRESSABLE (x))
3298 error ("address taken, but ADDRESSABLE bit not set");
3305 x = COND_EXPR_COND (t);
3306 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3308 error ("non-boolean used in condition");
3311 if (!is_gimple_condexpr (x))
3313 error ("invalid conditional operand");
3320 case FIX_TRUNC_EXPR:
3322 case FIX_FLOOR_EXPR:
3323 case FIX_ROUND_EXPR:
3328 case NON_LVALUE_EXPR:
3329 case TRUTH_NOT_EXPR:
3330 CHECK_OP (0, "invalid operand to unary operator");
3337 case ARRAY_RANGE_REF:
3339 case VIEW_CONVERT_EXPR:
3340 /* We have a nest of references. Verify that each of the operands
3341 that determine where to reference is either a constant or a variable,
3342 verify that the base is valid, and then show we've already checked
3344 while (handled_component_p (t))
3346 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3347 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3348 else if (TREE_CODE (t) == ARRAY_REF
3349 || TREE_CODE (t) == ARRAY_RANGE_REF)
3351 CHECK_OP (1, "invalid array index");
3352 if (TREE_OPERAND (t, 2))
3353 CHECK_OP (2, "invalid array lower bound");
3354 if (TREE_OPERAND (t, 3))
3355 CHECK_OP (3, "invalid array stride");
3357 else if (TREE_CODE (t) == BIT_FIELD_REF)
3359 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3360 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3363 t = TREE_OPERAND (t, 0);
3366 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3368 error ("invalid reference prefix");
3380 case UNORDERED_EXPR:
3391 case TRUNC_DIV_EXPR:
3393 case FLOOR_DIV_EXPR:
3394 case ROUND_DIV_EXPR:
3395 case TRUNC_MOD_EXPR:
3397 case FLOOR_MOD_EXPR:
3398 case ROUND_MOD_EXPR:
3400 case EXACT_DIV_EXPR:
3410 CHECK_OP (0, "invalid operand to binary operator");
3411 CHECK_OP (1, "invalid operand to binary operator");
3423 /* Verify STMT, return true if STMT is not in GIMPLE form.
3424 TODO: Implement type checking. */
3427 verify_stmt (tree stmt, bool last_in_block)
3431 if (OMP_DIRECTIVE_P (stmt))
3433 /* OpenMP directives are validated by the FE and never operated
3434 on by the optimizers. Furthermore, OMP_FOR may contain
3435 non-gimple expressions when the main index variable has had
3436 its address taken. This does not affect the loop itself
3437 because the header of an OMP_FOR is merely used to determine
3438 how to setup the parallel iteration. */
3442 if (!is_gimple_stmt (stmt))
3444 error ("is not a valid GIMPLE statement");
3448 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3451 debug_generic_stmt (addr);
3455 /* If the statement is marked as part of an EH region, then it is
3456 expected that the statement could throw. Verify that when we
3457 have optimizations that simplify statements such that we prove
3458 that they cannot throw, that we update other data structures
3460 if (lookup_stmt_eh_region (stmt) >= 0)
3462 if (!tree_could_throw_p (stmt))
3464 error ("statement marked for throw, but doesn%'t");
3467 if (!last_in_block && tree_can_throw_internal (stmt))
3469 error ("statement marked for throw in middle of block");
3477 debug_generic_stmt (stmt);
3482 /* Return true when the T can be shared. */
3485 tree_node_can_be_shared (tree t)
3487 if (IS_TYPE_OR_DECL_P (t)
3488 || is_gimple_min_invariant (t)
3489 || TREE_CODE (t) == SSA_NAME
3490 || t == error_mark_node
3491 || TREE_CODE (t) == IDENTIFIER_NODE)
3494 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3497 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3498 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3499 || TREE_CODE (t) == COMPONENT_REF
3500 || TREE_CODE (t) == REALPART_EXPR
3501 || TREE_CODE (t) == IMAGPART_EXPR)
3502 t = TREE_OPERAND (t, 0);
3511 /* Called via walk_trees. Verify tree sharing. */
3514 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3516 htab_t htab = (htab_t) data;
3519 if (tree_node_can_be_shared (*tp))
3521 *walk_subtrees = false;
3525 slot = htab_find_slot (htab, *tp, INSERT);
3527 return (tree) *slot;
3534 /* Verify the GIMPLE statement chain. */
3540 block_stmt_iterator bsi;
3545 timevar_push (TV_TREE_STMT_VERIFY);
3546 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3553 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3555 int phi_num_args = PHI_NUM_ARGS (phi);
3557 if (bb_for_stmt (phi) != bb)
3559 error ("bb_for_stmt (phi) is set to a wrong basic block");
3563 for (i = 0; i < phi_num_args; i++)
3565 tree t = PHI_ARG_DEF (phi, i);
3568 /* Addressable variables do have SSA_NAMEs but they
3569 are not considered gimple values. */
3570 if (TREE_CODE (t) != SSA_NAME
3571 && TREE_CODE (t) != FUNCTION_DECL
3572 && !is_gimple_val (t))
3574 error ("PHI def is not a GIMPLE value");
3575 debug_generic_stmt (phi);
3576 debug_generic_stmt (t);
3580 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3583 debug_generic_stmt (addr);
3587 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3590 error ("incorrect sharing of tree nodes");
3591 debug_generic_stmt (phi);
3592 debug_generic_stmt (addr);
3598 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3600 tree stmt = bsi_stmt (bsi);
3602 if (bb_for_stmt (stmt) != bb)
3604 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3609 err |= verify_stmt (stmt, bsi_end_p (bsi));
3610 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3613 error ("incorrect sharing of tree nodes");
3614 debug_generic_stmt (stmt);
3615 debug_generic_stmt (addr);
3622 internal_error ("verify_stmts failed");
3625 timevar_pop (TV_TREE_STMT_VERIFY);
3629 /* Verifies that the flow information is OK. */
3632 tree_verify_flow_info (void)
3636 block_stmt_iterator bsi;
3641 if (ENTRY_BLOCK_PTR->stmt_list)
3643 error ("ENTRY_BLOCK has a statement list associated with it");
3647 if (EXIT_BLOCK_PTR->stmt_list)
3649 error ("EXIT_BLOCK has a statement list associated with it");
3653 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3654 if (e->flags & EDGE_FALLTHRU)
3656 error ("fallthru to exit from bb %d", e->src->index);
3662 bool found_ctrl_stmt = false;
3666 /* Skip labels on the start of basic block. */
3667 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3669 tree prev_stmt = stmt;
3671 stmt = bsi_stmt (bsi);
3673 if (TREE_CODE (stmt) != LABEL_EXPR)
3676 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3678 error ("nonlocal label ");
3679 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3680 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3685 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3688 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3689 fprintf (stderr, " to block does not match in bb %d",
3694 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3695 != current_function_decl)
3698 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3699 fprintf (stderr, " has incorrect context in bb %d",
3705 /* Verify that body of basic block BB is free of control flow. */
3706 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3708 tree stmt = bsi_stmt (bsi);
3710 if (found_ctrl_stmt)
3712 error ("control flow in the middle of basic block %d",
3717 if (stmt_ends_bb_p (stmt))
3718 found_ctrl_stmt = true;
3720 if (TREE_CODE (stmt) == LABEL_EXPR)
3723 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3724 fprintf (stderr, " in the middle of basic block %d", bb->index);
3729 bsi = bsi_last (bb);
3730 if (bsi_end_p (bsi))
3733 stmt = bsi_stmt (bsi);
3735 err |= verify_eh_edges (stmt);
3737 if (is_ctrl_stmt (stmt))
3739 FOR_EACH_EDGE (e, ei, bb->succs)
3740 if (e->flags & EDGE_FALLTHRU)
3742 error ("fallthru edge after a control statement in bb %d",
3748 switch (TREE_CODE (stmt))
3754 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3755 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3757 error ("structured COND_EXPR at the end of bb %d", bb->index);
3761 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3763 if (!true_edge || !false_edge
3764 || !(true_edge->flags & EDGE_TRUE_VALUE)
3765 || !(false_edge->flags & EDGE_FALSE_VALUE)
3766 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3767 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3768 || EDGE_COUNT (bb->succs) >= 3)
3770 error ("wrong outgoing edge flags at end of bb %d",
3775 if (!has_label_p (true_edge->dest,
3776 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3778 error ("%<then%> label does not match edge at end of bb %d",
3783 if (!has_label_p (false_edge->dest,
3784 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3786 error ("%<else%> label does not match edge at end of bb %d",
3794 if (simple_goto_p (stmt))
3796 error ("explicit goto at end of bb %d", bb->index);
3801 /* FIXME. We should double check that the labels in the
3802 destination blocks have their address taken. */
3803 FOR_EACH_EDGE (e, ei, bb->succs)
3804 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3805 | EDGE_FALSE_VALUE))
3806 || !(e->flags & EDGE_ABNORMAL))
3808 error ("wrong outgoing edge flags at end of bb %d",
3816 if (!single_succ_p (bb)
3817 || (single_succ_edge (bb)->flags
3818 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3819 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3821 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3824 if (single_succ (bb) != EXIT_BLOCK_PTR)
3826 error ("return edge does not point to exit in bb %d",
3839 vec = SWITCH_LABELS (stmt);
3840 n = TREE_VEC_LENGTH (vec);
3842 /* Mark all the destination basic blocks. */
3843 for (i = 0; i < n; ++i)
3845 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3846 basic_block label_bb = label_to_block (lab);
3848 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3849 label_bb->aux = (void *)1;
3852 /* Verify that the case labels are sorted. */
3853 prev = TREE_VEC_ELT (vec, 0);
3854 for (i = 1; i < n - 1; ++i)
3856 tree c = TREE_VEC_ELT (vec, i);
3859 error ("found default case not at end of case vector");
3863 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3865 error ("case labels not sorted: ");
3866 print_generic_expr (stderr, prev, 0);
3867 fprintf (stderr," is greater than ");
3868 print_generic_expr (stderr, c, 0);
3869 fprintf (stderr," but comes before it.\n");
3874 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3876 error ("no default case found at end of case vector");
3880 FOR_EACH_EDGE (e, ei, bb->succs)
3884 error ("extra outgoing edge %d->%d",
3885 bb->index, e->dest->index);
3888 e->dest->aux = (void *)2;
3889 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3890 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3892 error ("wrong outgoing edge flags at end of bb %d",
3898 /* Check that we have all of them. */
3899 for (i = 0; i < n; ++i)
3901 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3902 basic_block label_bb = label_to_block (lab);
3904 if (label_bb->aux != (void *)2)
3906 error ("missing edge %i->%i",
3907 bb->index, label_bb->index);
3912 FOR_EACH_EDGE (e, ei, bb->succs)
3913 e->dest->aux = (void *)0;
3920 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3921 verify_dominators (CDI_DOMINATORS);
3927 /* Updates phi nodes after creating a forwarder block joined
3928 by edge FALLTHRU. */
3931 tree_make_forwarder_block (edge fallthru)
3935 basic_block dummy, bb;
3936 tree phi, new_phi, var;
3938 dummy = fallthru->src;
3939 bb = fallthru->dest;
3941 if (single_pred_p (bb))
3944 /* If we redirected a branch we must create new phi nodes at the
3946 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3948 var = PHI_RESULT (phi);
3949 new_phi = create_phi_node (var, bb);
3950 SSA_NAME_DEF_STMT (var) = new_phi;
3951 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3952 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3955 /* Ensure that the PHI node chain is in the same order. */
3956 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3958 /* Add the arguments we have stored on edges. */
3959 FOR_EACH_EDGE (e, ei, bb->preds)
3964 flush_pending_stmts (e);
3969 /* Return a non-special label in the head of basic block BLOCK.
3970 Create one if it doesn't exist. */
3973 tree_block_label (basic_block bb)
3975 block_stmt_iterator i, s = bsi_start (bb);
3979 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
3981 stmt = bsi_stmt (i);
3982 if (TREE_CODE (stmt) != LABEL_EXPR)
3984 label = LABEL_EXPR_LABEL (stmt);
3985 if (!DECL_NONLOCAL (label))
3988 bsi_move_before (&i, &s);
3993 label = create_artificial_label ();
3994 stmt = build1 (LABEL_EXPR, void_type_node, label);
3995 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4000 /* Attempt to perform edge redirection by replacing a possibly complex
4001 jump instruction by a goto or by removing the jump completely.
4002 This can apply only if all edges now point to the same block. The
4003 parameters and return values are equivalent to
4004 redirect_edge_and_branch. */
4007 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4009 basic_block src = e->src;
4010 block_stmt_iterator b;
4013 /* We can replace or remove a complex jump only when we have exactly
4015 if (EDGE_COUNT (src->succs) != 2
4016 /* Verify that all targets will be TARGET. Specifically, the
4017 edge that is not E must also go to TARGET. */
4018 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4024 stmt = bsi_stmt (b);
4026 if (TREE_CODE (stmt) == COND_EXPR
4027 || TREE_CODE (stmt) == SWITCH_EXPR)
4029 bsi_remove (&b, true);
4030 e = ssa_redirect_edge (e, target);
4031 e->flags = EDGE_FALLTHRU;
4039 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4040 edge representing the redirected branch. */
4043 tree_redirect_edge_and_branch (edge e, basic_block dest)
4045 basic_block bb = e->src;
4046 block_stmt_iterator bsi;
4050 if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
4053 if (e->src != ENTRY_BLOCK_PTR
4054 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4057 if (e->dest == dest)
4060 label = tree_block_label (dest);
4062 bsi = bsi_last (bb);
4063 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4065 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4068 stmt = (e->flags & EDGE_TRUE_VALUE
4069 ? COND_EXPR_THEN (stmt)
4070 : COND_EXPR_ELSE (stmt));
4071 GOTO_DESTINATION (stmt) = label;
4075 /* No non-abnormal edges should lead from a non-simple goto, and
4076 simple ones should be represented implicitly. */
4081 tree cases = get_cases_for_edge (e, stmt);
4083 /* If we have a list of cases associated with E, then use it
4084 as it's a lot faster than walking the entire case vector. */
4087 edge e2 = find_edge (e->src, dest);
4094 CASE_LABEL (cases) = label;
4095 cases = TREE_CHAIN (cases);
4098 /* If there was already an edge in the CFG, then we need
4099 to move all the cases associated with E to E2. */
4102 tree cases2 = get_cases_for_edge (e2, stmt);
4104 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4105 TREE_CHAIN (cases2) = first;
4110 tree vec = SWITCH_LABELS (stmt);
4111 size_t i, n = TREE_VEC_LENGTH (vec);
4113 for (i = 0; i < n; i++)
4115 tree elt = TREE_VEC_ELT (vec, i);
4117 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4118 CASE_LABEL (elt) = label;
4126 bsi_remove (&bsi, true);
4127 e->flags |= EDGE_FALLTHRU;
4131 /* Otherwise it must be a fallthru edge, and we don't need to
4132 do anything besides redirecting it. */
4133 gcc_assert (e->flags & EDGE_FALLTHRU);
4137 /* Update/insert PHI nodes as necessary. */
4139 /* Now update the edges in the CFG. */
4140 e = ssa_redirect_edge (e, dest);
4146 /* Simple wrapper, as we can always redirect fallthru edges. */
4149 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4151 e = tree_redirect_edge_and_branch (e, dest);
4158 /* Splits basic block BB after statement STMT (but at least after the
4159 labels). If STMT is NULL, BB is split just after the labels. */
4162 tree_split_block (basic_block bb, void *stmt)
4164 block_stmt_iterator bsi, bsi_tgt;
4170 new_bb = create_empty_bb (bb);
4172 /* Redirect the outgoing edges. */
4173 new_bb->succs = bb->succs;
4175 FOR_EACH_EDGE (e, ei, new_bb->succs)
4178 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4181 /* Move everything from BSI to the new basic block. */
4182 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4184 act = bsi_stmt (bsi);
4185 if (TREE_CODE (act) == LABEL_EXPR)
4198 bsi_tgt = bsi_start (new_bb);
4199 while (!bsi_end_p (bsi))
4201 act = bsi_stmt (bsi);
4202 bsi_remove (&bsi, false);
4203 bsi_insert_after (&bsi_tgt, act, BSI_NEW_STMT);
4210 /* Moves basic block BB after block AFTER. */
4213 tree_move_block_after (basic_block bb, basic_block after)
4215 if (bb->prev_bb == after)
4219 link_block (bb, after);
4225 /* Return true if basic_block can be duplicated. */
4228 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4234 /* Create a duplicate of the basic block BB. NOTE: This does not
4235 preserve SSA form. */
4238 tree_duplicate_bb (basic_block bb)
4241 block_stmt_iterator bsi, bsi_tgt;
4244 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4246 /* Copy the PHI nodes. We ignore PHI node arguments here because
4247 the incoming edges have not been setup yet. */
4248 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4250 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4251 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4254 /* Keep the chain of PHI nodes in the same order so that they can be
4255 updated by ssa_redirect_edge. */
4256 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4258 bsi_tgt = bsi_start (new_bb);
4259 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4261 def_operand_p def_p;
4262 ssa_op_iter op_iter;
4266 stmt = bsi_stmt (bsi);
4267 if (TREE_CODE (stmt) == LABEL_EXPR)
4270 /* Create a new copy of STMT and duplicate STMT's virtual
4272 copy = unshare_expr (stmt);
4273 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4274 copy_virtual_operands (copy, stmt);
4275 region = lookup_stmt_eh_region (stmt);
4277 add_stmt_to_eh_region (copy, region);
4279 /* Create new names for all the definitions created by COPY and
4280 add replacement mappings for each new name. */
4281 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4282 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4289 /* Basic block BB_COPY was created by code duplication. Add phi node
4290 arguments for edges going out of BB_COPY. The blocks that were
4291 duplicated have BB_DUPLICATED set. */
4294 add_phi_args_after_copy_bb (basic_block bb_copy)
4296 basic_block bb, dest;
4299 tree phi, phi_copy, phi_next, def;
4301 bb = get_bb_original (bb_copy);
4303 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4305 if (!phi_nodes (e_copy->dest))
4308 if (e_copy->dest->flags & BB_DUPLICATED)
4309 dest = get_bb_original (e_copy->dest);
4311 dest = e_copy->dest;
4313 e = find_edge (bb, dest);
4316 /* During loop unrolling the target of the latch edge is copied.
4317 In this case we are not looking for edge to dest, but to
4318 duplicated block whose original was dest. */
4319 FOR_EACH_EDGE (e, ei, bb->succs)
4320 if ((e->dest->flags & BB_DUPLICATED)
4321 && get_bb_original (e->dest) == dest)
4324 gcc_assert (e != NULL);
4327 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4329 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4331 phi_next = PHI_CHAIN (phi);
4332 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4333 add_phi_arg (phi_copy, def, e_copy);
4338 /* Blocks in REGION_COPY array of length N_REGION were created by
4339 duplication of basic blocks. Add phi node arguments for edges
4340 going from these blocks. */
4343 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4347 for (i = 0; i < n_region; i++)
4348 region_copy[i]->flags |= BB_DUPLICATED;
4350 for (i = 0; i < n_region; i++)
4351 add_phi_args_after_copy_bb (region_copy[i]);
4353 for (i = 0; i < n_region; i++)
4354 region_copy[i]->flags &= ~BB_DUPLICATED;
4357 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4358 important exit edge EXIT. By important we mean that no SSA name defined
4359 inside region is live over the other exit edges of the region. All entry
4360 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4361 to the duplicate of the region. SSA form, dominance and loop information
4362 is updated. The new basic blocks are stored to REGION_COPY in the same
4363 order as they had in REGION, provided that REGION_COPY is not NULL.
4364 The function returns false if it is unable to copy the region,
4368 tree_duplicate_sese_region (edge entry, edge exit,
4369 basic_block *region, unsigned n_region,
4370 basic_block *region_copy)
4373 bool free_region_copy = false, copying_header = false;
4374 struct loop *loop = entry->dest->loop_father;
4378 int total_freq = 0, entry_freq = 0;
4379 gcov_type total_count = 0, entry_count = 0;
4381 if (!can_copy_bbs_p (region, n_region))
4384 /* Some sanity checking. Note that we do not check for all possible
4385 missuses of the functions. I.e. if you ask to copy something weird,
4386 it will work, but the state of structures probably will not be
4388 for (i = 0; i < n_region; i++)
4390 /* We do not handle subloops, i.e. all the blocks must belong to the
4392 if (region[i]->loop_father != loop)
4395 if (region[i] != entry->dest
4396 && region[i] == loop->header)
4402 /* In case the function is used for loop header copying (which is the primary
4403 use), ensure that EXIT and its copy will be new latch and entry edges. */
4404 if (loop->header == entry->dest)
4406 copying_header = true;
4407 loop->copy = loop->outer;
4409 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4412 for (i = 0; i < n_region; i++)
4413 if (region[i] != exit->src
4414 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4420 region_copy = XNEWVEC (basic_block, n_region);
4421 free_region_copy = true;
4424 gcc_assert (!need_ssa_update_p ());
4426 /* Record blocks outside the region that are dominated by something
4428 doms = XNEWVEC (basic_block, n_basic_blocks);
4429 initialize_original_copy_tables ();
4431 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4433 if (entry->dest->count)
4435 total_count = entry->dest->count;
4436 entry_count = entry->count;
4437 /* Fix up corner cases, to avoid division by zero or creation of negative
4439 if (entry_count > total_count)
4440 entry_count = total_count;
4444 total_freq = entry->dest->frequency;
4445 entry_freq = EDGE_FREQUENCY (entry);
4446 /* Fix up corner cases, to avoid division by zero or creation of negative
4448 if (total_freq == 0)
4450 else if (entry_freq > total_freq)
4451 entry_freq = total_freq;
4454 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4455 split_edge_bb_loc (entry));
4458 scale_bbs_frequencies_gcov_type (region, n_region,
4459 total_count - entry_count,
4461 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4466 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4468 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4473 loop->header = exit->dest;
4474 loop->latch = exit->src;
4477 /* Redirect the entry and add the phi node arguments. */
4478 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4479 gcc_assert (redirected != NULL);
4480 flush_pending_stmts (entry);
4482 /* Concerning updating of dominators: We must recount dominators
4483 for entry block and its copy. Anything that is outside of the
4484 region, but was dominated by something inside needs recounting as
4486 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4487 doms[n_doms++] = get_bb_original (entry->dest);
4488 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4491 /* Add the other PHI node arguments. */
4492 add_phi_args_after_copy (region_copy, n_region);
4494 /* Update the SSA web. */
4495 update_ssa (TODO_update_ssa);
4497 if (free_region_copy)
4500 free_original_copy_tables ();
4505 DEF_VEC_P(basic_block);
4506 DEF_VEC_ALLOC_P(basic_block,heap);
4509 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4510 adding blocks when the dominator traversal reaches EXIT. This
4511 function silently assumes that ENTRY strictly dominates EXIT. */
4514 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4515 VEC(basic_block,heap) **bbs_p)
4519 for (son = first_dom_son (CDI_DOMINATORS, entry);
4521 son = next_dom_son (CDI_DOMINATORS, son))
4523 VEC_safe_push (basic_block, heap, *bbs_p, son);
4525 gather_blocks_in_sese_region (son, exit, bbs_p);
4535 bitmap vars_to_remove;
4536 htab_t new_label_map;
4540 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4541 contained in *TP and change the DECL_CONTEXT of every local
4542 variable referenced in *TP. */
4545 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4547 struct move_stmt_d *p = (struct move_stmt_d *) data;
4550 if (p->block && IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t))))
4551 TREE_BLOCK (t) = p->block;
4553 if (OMP_DIRECTIVE_P (t)
4554 && TREE_CODE (t) != OMP_RETURN
4555 && TREE_CODE (t) != OMP_CONTINUE)
4557 /* Do not remap variables inside OMP directives. Variables
4558 referenced in clauses and directive header belong to the
4559 parent function and should not be moved into the child
4561 bool save_remap_decls_p = p->remap_decls_p;
4562 p->remap_decls_p = false;
4565 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4567 p->remap_decls_p = save_remap_decls_p;
4569 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4571 if (TREE_CODE (t) == LABEL_DECL)
4573 if (p->new_label_map)
4575 struct tree_map in, *out;
4577 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4582 DECL_CONTEXT (t) = p->to_context;
4584 else if (p->remap_decls_p)
4586 DECL_CONTEXT (t) = p->to_context;
4588 if (TREE_CODE (t) == VAR_DECL)
4590 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4591 f->unexpanded_var_list
4592 = tree_cons (0, t, f->unexpanded_var_list);
4594 /* Mark T to be removed from the original function,
4595 otherwise it will be given a DECL_RTL when the
4596 original function is expanded. */
4597 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4601 else if (TYPE_P (t))
4608 /* Move basic block BB from function CFUN to function DEST_FN. The
4609 block is moved out of the original linked list and placed after
4610 block AFTER in the new list. Also, the block is removed from the
4611 original array of blocks and placed in DEST_FN's array of blocks.
4612 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4613 updated to reflect the moved edges.
4615 On exit, local variables that need to be removed from
4616 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4619 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4620 basic_block after, bool update_edge_count_p,
4621 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4623 struct control_flow_graph *cfg;
4626 block_stmt_iterator si;
4627 struct move_stmt_d d;
4628 unsigned old_len, new_len;
4631 /* Link BB to the new linked list. */
4632 move_block_after (bb, after);
4634 /* Update the edge count in the corresponding flowgraphs. */
4635 if (update_edge_count_p)
4636 FOR_EACH_EDGE (e, ei, bb->succs)
4638 cfun->cfg->x_n_edges--;
4639 dest_cfun->cfg->x_n_edges++;
4642 /* Remove BB from the original basic block array. */
4643 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4644 cfun->cfg->x_n_basic_blocks--;
4646 /* Grow DEST_CFUN's basic block array if needed. */
4647 cfg = dest_cfun->cfg;
4648 cfg->x_n_basic_blocks++;
4649 if (bb->index > cfg->x_last_basic_block)
4650 cfg->x_last_basic_block = bb->index;
4652 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4653 if ((unsigned) cfg->x_last_basic_block >= old_len)
4655 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4656 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4657 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4658 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4661 VEC_replace (basic_block, cfg->x_basic_block_info,
4662 cfg->x_last_basic_block, bb);
4664 /* The statements in BB need to be associated with a new TREE_BLOCK.
4665 Labels need to be associated with a new label-to-block map. */
4666 memset (&d, 0, sizeof (d));
4667 d.vars_to_remove = vars_to_remove;
4669 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4671 tree stmt = bsi_stmt (si);
4674 d.from_context = cfun->decl;
4675 d.to_context = dest_cfun->decl;
4676 d.remap_decls_p = true;
4677 d.new_label_map = new_label_map;
4678 if (TREE_BLOCK (stmt))
4679 d.block = DECL_INITIAL (dest_cfun->decl);
4681 walk_tree (&stmt, move_stmt_r, &d, NULL);
4683 if (TREE_CODE (stmt) == LABEL_EXPR)
4685 tree label = LABEL_EXPR_LABEL (stmt);
4686 int uid = LABEL_DECL_UID (label);
4688 gcc_assert (uid > -1);
4690 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4691 if (old_len <= (unsigned) uid)
4693 new_len = 3 * uid / 2;
4694 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4696 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4697 memset (&addr[old_len], 0,
4698 sizeof (basic_block) * (new_len - old_len));
4701 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4702 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4704 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4706 if (uid >= dest_cfun->last_label_uid)
4707 dest_cfun->last_label_uid = uid + 1;
4709 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4710 TREE_OPERAND (stmt, 0) =
4711 build_int_cst (NULL_TREE,
4712 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4715 region = lookup_stmt_eh_region (stmt);
4718 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4719 remove_stmt_from_eh_region (stmt);
4724 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4725 the outermost EH region. Use REGION as the incoming base EH region. */
4728 find_outermost_region_in_block (struct function *src_cfun,
4729 basic_block bb, int region)
4731 block_stmt_iterator si;
4733 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4735 tree stmt = bsi_stmt (si);
4738 if (TREE_CODE (stmt) == RESX_EXPR)
4739 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4741 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4742 if (stmt_region > 0)
4745 region = stmt_region;
4746 else if (stmt_region != region)
4748 region = eh_region_outermost (src_cfun, stmt_region, region);
4749 gcc_assert (region != -1);
4758 new_label_mapper (tree decl, void *data)
4760 htab_t hash = (htab_t) data;
4764 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4766 m = xmalloc (sizeof (struct tree_map));
4767 m->hash = DECL_UID (decl);
4769 m->to = create_artificial_label ();
4770 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4772 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4773 gcc_assert (*slot == NULL);
4780 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4781 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4782 single basic block in the original CFG and the new basic block is
4783 returned. DEST_CFUN must not have a CFG yet.
4785 Note that the region need not be a pure SESE region. Blocks inside
4786 the region may contain calls to abort/exit. The only restriction
4787 is that ENTRY_BB should be the only entry point and it must
4790 All local variables referenced in the region are assumed to be in
4791 the corresponding BLOCK_VARS and unexpanded variable lists
4792 associated with DEST_CFUN. */
4795 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4796 basic_block exit_bb)
4798 VEC(basic_block,heap) *bbs;
4799 basic_block after, bb, *entry_pred, *exit_succ;
4800 struct function *saved_cfun;
4801 int *entry_flag, *exit_flag, eh_offset;
4802 unsigned i, num_entry_edges, num_exit_edges;
4805 bitmap vars_to_remove;
4806 htab_t new_label_map;
4810 /* Collect all the blocks in the region. Manually add ENTRY_BB
4811 because it won't be added by dfs_enumerate_from. */
4812 calculate_dominance_info (CDI_DOMINATORS);
4814 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4816 gcc_assert (entry_bb != exit_bb
4818 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4821 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4822 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4824 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4825 the predecessor edges to ENTRY_BB and the successor edges to
4826 EXIT_BB so that we can re-attach them to the new basic block that
4827 will replace the region. */
4828 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4829 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4830 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4832 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4834 entry_flag[i] = e->flags;
4835 entry_pred[i++] = e->src;
4841 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4842 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4843 sizeof (basic_block));
4844 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4846 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4848 exit_flag[i] = e->flags;
4849 exit_succ[i++] = e->dest;
4860 /* Switch context to the child function to initialize DEST_FN's CFG. */
4861 gcc_assert (dest_cfun->cfg == NULL);
4864 init_empty_tree_cfg ();
4866 /* Initialize EH information for the new function. */
4868 new_label_map = NULL;
4873 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4874 region = find_outermost_region_in_block (saved_cfun, bb, region);
4876 init_eh_for_function ();
4879 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4880 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4881 new_label_map, region, 0);
4887 /* Move blocks from BBS into DEST_CFUN. */
4888 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4889 after = dest_cfun->cfg->x_entry_block_ptr;
4890 vars_to_remove = BITMAP_ALLOC (NULL);
4891 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4893 /* No need to update edge counts on the last block. It has
4894 already been updated earlier when we detached the region from
4895 the original CFG. */
4896 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4897 new_label_map, eh_offset);
4902 htab_delete (new_label_map);
4904 /* Remove the variables marked in VARS_TO_REMOVE from
4905 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4906 DECL_RTL in the context of CFUN. */
4907 if (!bitmap_empty_p (vars_to_remove))
4911 for (p = &cfun->unexpanded_var_list; *p; )
4913 tree var = TREE_VALUE (*p);
4914 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4916 *p = TREE_CHAIN (*p);
4920 p = &TREE_CHAIN (*p);
4924 BITMAP_FREE (vars_to_remove);
4926 /* Rewire the entry and exit blocks. The successor to the entry
4927 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4928 the child function. Similarly, the predecessor of DEST_FN's
4929 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4930 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4931 various CFG manipulation function get to the right CFG.
4933 FIXME, this is silly. The CFG ought to become a parameter to
4936 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4938 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4941 /* Back in the original function, the SESE region has disappeared,
4942 create a new basic block in its place. */
4943 bb = create_empty_bb (entry_pred[0]);
4944 for (i = 0; i < num_entry_edges; i++)
4945 make_edge (entry_pred[i], bb, entry_flag[i]);
4947 for (i = 0; i < num_exit_edges; i++)
4948 make_edge (bb, exit_succ[i], exit_flag[i]);
4957 free_dominance_info (CDI_DOMINATORS);
4958 free_dominance_info (CDI_POST_DOMINATORS);
4959 VEC_free (basic_block, heap, bbs);
4965 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4968 dump_function_to_file (tree fn, FILE *file, int flags)
4970 tree arg, vars, var;
4971 bool ignore_topmost_bind = false, any_var = false;
4974 struct function *saved_cfun;
4976 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
4978 arg = DECL_ARGUMENTS (fn);
4981 print_generic_expr (file, arg, dump_flags);
4982 if (TREE_CHAIN (arg))
4983 fprintf (file, ", ");
4984 arg = TREE_CHAIN (arg);
4986 fprintf (file, ")\n");
4988 if (flags & TDF_DETAILS)
4989 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
4990 if (flags & TDF_RAW)
4992 dump_node (fn, TDF_SLIM | flags, file);
4996 /* Switch CFUN to point to FN. */
4998 cfun = DECL_STRUCT_FUNCTION (fn);
5000 /* When GIMPLE is lowered, the variables are no longer available in
5001 BIND_EXPRs, so display them separately. */
5002 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5004 ignore_topmost_bind = true;
5006 fprintf (file, "{\n");
5007 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5009 var = TREE_VALUE (vars);
5011 print_generic_decl (file, var, flags);
5012 fprintf (file, "\n");
5018 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5020 /* Make a CFG based dump. */
5021 check_bb_profile (ENTRY_BLOCK_PTR, file);
5022 if (!ignore_topmost_bind)
5023 fprintf (file, "{\n");
5025 if (any_var && n_basic_blocks)
5026 fprintf (file, "\n");
5029 dump_generic_bb (file, bb, 2, flags);
5031 fprintf (file, "}\n");
5032 check_bb_profile (EXIT_BLOCK_PTR, file);
5038 /* Make a tree based dump. */
5039 chain = DECL_SAVED_TREE (fn);
5041 if (chain && TREE_CODE (chain) == BIND_EXPR)
5043 if (ignore_topmost_bind)
5045 chain = BIND_EXPR_BODY (chain);
5053 if (!ignore_topmost_bind)
5054 fprintf (file, "{\n");
5059 fprintf (file, "\n");
5061 print_generic_stmt_indented (file, chain, flags, indent);
5062 if (ignore_topmost_bind)
5063 fprintf (file, "}\n");
5066 fprintf (file, "\n\n");
5073 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5076 debug_function (tree fn, int flags)
5078 dump_function_to_file (fn, stderr, flags);
5082 /* Pretty print of the loops intermediate representation. */
5083 static void print_loop (FILE *, struct loop *, int);
5084 static void print_pred_bbs (FILE *, basic_block bb);
5085 static void print_succ_bbs (FILE *, basic_block bb);
5088 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5091 print_pred_bbs (FILE *file, basic_block bb)
5096 FOR_EACH_EDGE (e, ei, bb->preds)
5097 fprintf (file, "bb_%d ", e->src->index);
5101 /* Print on FILE the indexes for the successors of basic_block BB. */
5104 print_succ_bbs (FILE *file, basic_block bb)
5109 FOR_EACH_EDGE (e, ei, bb->succs)
5110 fprintf (file, "bb_%d ", e->dest->index);
5114 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5117 print_loop (FILE *file, struct loop *loop, int indent)
5125 s_indent = (char *) alloca ((size_t) indent + 1);
5126 memset ((void *) s_indent, ' ', (size_t) indent);
5127 s_indent[indent] = '\0';
5129 /* Print the loop's header. */
5130 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5132 /* Print the loop's body. */
5133 fprintf (file, "%s{\n", s_indent);
5135 if (bb->loop_father == loop)
5137 /* Print the basic_block's header. */
5138 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5139 print_pred_bbs (file, bb);
5140 fprintf (file, "}, succs = {");
5141 print_succ_bbs (file, bb);
5142 fprintf (file, "})\n");
5144 /* Print the basic_block's body. */
5145 fprintf (file, "%s {\n", s_indent);
5146 tree_dump_bb (bb, file, indent + 4);
5147 fprintf (file, "%s }\n", s_indent);
5150 print_loop (file, loop->inner, indent + 2);
5151 fprintf (file, "%s}\n", s_indent);
5152 print_loop (file, loop->next, indent);
5156 /* Follow a CFG edge from the entry point of the program, and on entry
5157 of a loop, pretty print the loop structure on FILE. */
5160 print_loop_ir (FILE *file)
5164 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5165 if (bb && bb->loop_father)
5166 print_loop (file, bb->loop_father, 0);
5170 /* Debugging loops structure at tree level. */
5173 debug_loop_ir (void)
5175 print_loop_ir (stderr);
5179 /* Return true if BB ends with a call, possibly followed by some
5180 instructions that must stay with the call. Return false,
5184 tree_block_ends_with_call_p (basic_block bb)
5186 block_stmt_iterator bsi = bsi_last (bb);
5187 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5191 /* Return true if BB ends with a conditional branch. Return false,
5195 tree_block_ends_with_condjump_p (basic_block bb)
5197 tree stmt = last_stmt (bb);
5198 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5202 /* Return true if we need to add fake edge to exit at statement T.
5203 Helper function for tree_flow_call_edges_add. */
5206 need_fake_edge_p (tree t)
5210 /* NORETURN and LONGJMP calls already have an edge to exit.
5211 CONST and PURE calls do not need one.
5212 We don't currently check for CONST and PURE here, although
5213 it would be a good idea, because those attributes are
5214 figured out from the RTL in mark_constant_function, and
5215 the counter incrementation code from -fprofile-arcs
5216 leads to different results from -fbranch-probabilities. */
5217 call = get_call_expr_in (t);
5219 && !(call_expr_flags (call) & ECF_NORETURN))
5222 if (TREE_CODE (t) == ASM_EXPR
5223 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5230 /* Add fake edges to the function exit for any non constant and non
5231 noreturn calls, volatile inline assembly in the bitmap of blocks
5232 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5233 the number of blocks that were split.
5235 The goal is to expose cases in which entering a basic block does
5236 not imply that all subsequent instructions must be executed. */
5239 tree_flow_call_edges_add (sbitmap blocks)
5242 int blocks_split = 0;
5243 int last_bb = last_basic_block;
5244 bool check_last_block = false;
5246 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5250 check_last_block = true;
5252 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5254 /* In the last basic block, before epilogue generation, there will be
5255 a fallthru edge to EXIT. Special care is required if the last insn
5256 of the last basic block is a call because make_edge folds duplicate
5257 edges, which would result in the fallthru edge also being marked
5258 fake, which would result in the fallthru edge being removed by
5259 remove_fake_edges, which would result in an invalid CFG.
5261 Moreover, we can't elide the outgoing fake edge, since the block
5262 profiler needs to take this into account in order to solve the minimal
5263 spanning tree in the case that the call doesn't return.
5265 Handle this by adding a dummy instruction in a new last basic block. */
5266 if (check_last_block)
5268 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5269 block_stmt_iterator bsi = bsi_last (bb);
5271 if (!bsi_end_p (bsi))
5274 if (t && need_fake_edge_p (t))
5278 e = find_edge (bb, EXIT_BLOCK_PTR);
5281 bsi_insert_on_edge (e, build_empty_stmt ());
5282 bsi_commit_edge_inserts ();
5287 /* Now add fake edges to the function exit for any non constant
5288 calls since there is no way that we can determine if they will
5290 for (i = 0; i < last_bb; i++)
5292 basic_block bb = BASIC_BLOCK (i);
5293 block_stmt_iterator bsi;
5294 tree stmt, last_stmt;
5299 if (blocks && !TEST_BIT (blocks, i))
5302 bsi = bsi_last (bb);
5303 if (!bsi_end_p (bsi))
5305 last_stmt = bsi_stmt (bsi);
5308 stmt = bsi_stmt (bsi);
5309 if (need_fake_edge_p (stmt))
5312 /* The handling above of the final block before the
5313 epilogue should be enough to verify that there is
5314 no edge to the exit block in CFG already.
5315 Calling make_edge in such case would cause us to
5316 mark that edge as fake and remove it later. */
5317 #ifdef ENABLE_CHECKING
5318 if (stmt == last_stmt)
5320 e = find_edge (bb, EXIT_BLOCK_PTR);
5321 gcc_assert (e == NULL);
5325 /* Note that the following may create a new basic block
5326 and renumber the existing basic blocks. */
5327 if (stmt != last_stmt)
5329 e = split_block (bb, stmt);
5333 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5337 while (!bsi_end_p (bsi));
5342 verify_flow_info ();
5344 return blocks_split;
5348 tree_purge_dead_eh_edges (basic_block bb)
5350 bool changed = false;
5353 tree stmt = last_stmt (bb);
5355 if (stmt && tree_can_throw_internal (stmt))
5358 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5360 if (e->flags & EDGE_EH)
5369 /* Removal of dead EH edges might change dominators of not
5370 just immediate successors. E.g. when bb1 is changed so that
5371 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5372 eh edges purged by this function in:
5384 idom(bb5) must be recomputed. For now just free the dominance
5387 free_dominance_info (CDI_DOMINATORS);
5393 tree_purge_all_dead_eh_edges (bitmap blocks)
5395 bool changed = false;
5399 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5401 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5407 /* This function is called whenever a new edge is created or
5411 tree_execute_on_growing_pred (edge e)
5413 basic_block bb = e->dest;
5416 reserve_phi_args_for_new_edge (bb);
5419 /* This function is called immediately before edge E is removed from
5420 the edge vector E->dest->preds. */
5423 tree_execute_on_shrinking_pred (edge e)
5425 if (phi_nodes (e->dest))
5426 remove_phi_args (e);
5429 /*---------------------------------------------------------------------------
5430 Helper functions for Loop versioning
5431 ---------------------------------------------------------------------------*/
5433 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5434 of 'first'. Both of them are dominated by 'new_head' basic block. When
5435 'new_head' was created by 'second's incoming edge it received phi arguments
5436 on the edge by split_edge(). Later, additional edge 'e' was created to
5437 connect 'new_head' and 'first'. Now this routine adds phi args on this
5438 additional edge 'e' that new_head to second edge received as part of edge
5443 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5444 basic_block new_head, edge e)
5447 edge e2 = find_edge (new_head, second);
5449 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5450 edge, we should always have an edge from NEW_HEAD to SECOND. */
5451 gcc_assert (e2 != NULL);
5453 /* Browse all 'second' basic block phi nodes and add phi args to
5454 edge 'e' for 'first' head. PHI args are always in correct order. */
5456 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5458 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5460 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5461 add_phi_arg (phi1, def, e);
5465 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5466 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5467 the destination of the ELSE part. */
5469 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5470 basic_block cond_bb, void *cond_e)
5472 block_stmt_iterator bsi;
5473 tree goto1 = NULL_TREE;
5474 tree goto2 = NULL_TREE;
5475 tree new_cond_expr = NULL_TREE;
5476 tree cond_expr = (tree) cond_e;
5479 /* Build new conditional expr */
5480 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5481 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5482 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5484 /* Add new cond in cond_bb. */
5485 bsi = bsi_start (cond_bb);
5486 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5487 /* Adjust edges appropriately to connect new head with first head
5488 as well as second head. */
5489 e0 = single_succ_edge (cond_bb);
5490 e0->flags &= ~EDGE_FALLTHRU;
5491 e0->flags |= EDGE_FALSE_VALUE;
5494 struct cfg_hooks tree_cfg_hooks = {
5496 tree_verify_flow_info,
5497 tree_dump_bb, /* dump_bb */
5498 create_bb, /* create_basic_block */
5499 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5500 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5501 remove_bb, /* delete_basic_block */
5502 tree_split_block, /* split_block */
5503 tree_move_block_after, /* move_block_after */
5504 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5505 tree_merge_blocks, /* merge_blocks */
5506 tree_predict_edge, /* predict_edge */
5507 tree_predicted_by_p, /* predicted_by_p */
5508 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5509 tree_duplicate_bb, /* duplicate_block */
5510 tree_split_edge, /* split_edge */
5511 tree_make_forwarder_block, /* make_forward_block */
5512 NULL, /* tidy_fallthru_edge */
5513 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5514 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5515 tree_flow_call_edges_add, /* flow_call_edges_add */
5516 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5517 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5518 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5519 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5520 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5521 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5522 flush_pending_stmts /* flush_pending_stmts */
5526 /* Split all critical edges. */
5529 split_critical_edges (void)
5535 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5536 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5537 mappings around the calls to split_edge. */
5538 start_recording_case_labels ();
5541 FOR_EACH_EDGE (e, ei, bb->succs)
5542 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5547 end_recording_case_labels ();
5551 struct tree_opt_pass pass_split_crit_edges =
5553 "crited", /* name */
5555 split_critical_edges, /* execute */
5558 0, /* static_pass_number */
5559 TV_TREE_SPLIT_EDGES, /* tv_id */
5560 PROP_cfg, /* properties required */
5561 PROP_no_crit_edges, /* properties_provided */
5562 0, /* properties_destroyed */
5563 0, /* todo_flags_start */
5564 TODO_dump_func, /* todo_flags_finish */
5569 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5570 a temporary, make sure and register it to be renamed if necessary,
5571 and finally return the temporary. Put the statements to compute
5572 EXP before the current statement in BSI. */
5575 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5577 tree t, new_stmt, orig_stmt;
5579 if (is_gimple_val (exp))
5582 t = make_rename_temp (type, NULL);
5583 new_stmt = build2 (MODIFY_EXPR, type, t, exp);
5585 orig_stmt = bsi_stmt (*bsi);
5586 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5587 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5589 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5594 /* Build a ternary operation and gimplify it. Emit code before BSI.
5595 Return the gimple_val holding the result. */
5598 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5599 tree type, tree a, tree b, tree c)
5603 ret = fold_build3 (code, type, a, b, c);
5606 return gimplify_val (bsi, type, ret);
5609 /* Build a binary operation and gimplify it. Emit code before BSI.
5610 Return the gimple_val holding the result. */
5613 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5614 tree type, tree a, tree b)
5618 ret = fold_build2 (code, type, a, b);
5621 return gimplify_val (bsi, type, ret);
5624 /* Build a unary operation and gimplify it. Emit code before BSI.
5625 Return the gimple_val holding the result. */
5628 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5633 ret = fold_build1 (code, type, a);
5636 return gimplify_val (bsi, type, ret);
5641 /* Emit return warnings. */
5644 execute_warn_function_return (void)
5646 #ifdef USE_MAPPED_LOCATION
5647 source_location location;
5655 /* If we have a path to EXIT, then we do return. */
5656 if (TREE_THIS_VOLATILE (cfun->decl)
5657 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5659 #ifdef USE_MAPPED_LOCATION
5660 location = UNKNOWN_LOCATION;
5664 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5666 last = last_stmt (e->src);
5667 if (TREE_CODE (last) == RETURN_EXPR
5668 #ifdef USE_MAPPED_LOCATION
5669 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5671 && (locus = EXPR_LOCUS (last)) != NULL)
5675 #ifdef USE_MAPPED_LOCATION
5676 if (location == UNKNOWN_LOCATION)
5677 location = cfun->function_end_locus;
5678 warning (0, "%H%<noreturn%> function does return", &location);
5681 locus = &cfun->function_end_locus;
5682 warning (0, "%H%<noreturn%> function does return", locus);
5686 /* If we see "return;" in some basic block, then we do reach the end
5687 without returning a value. */
5688 else if (warn_return_type
5689 && !TREE_NO_WARNING (cfun->decl)
5690 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5691 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5693 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5695 tree last = last_stmt (e->src);
5696 if (TREE_CODE (last) == RETURN_EXPR
5697 && TREE_OPERAND (last, 0) == NULL
5698 && !TREE_NO_WARNING (last))
5700 #ifdef USE_MAPPED_LOCATION
5701 location = EXPR_LOCATION (last);
5702 if (location == UNKNOWN_LOCATION)
5703 location = cfun->function_end_locus;
5704 warning (0, "%Hcontrol reaches end of non-void function", &location);
5706 locus = EXPR_LOCUS (last);
5708 locus = &cfun->function_end_locus;
5709 warning (0, "%Hcontrol reaches end of non-void function", locus);
5711 TREE_NO_WARNING (cfun->decl) = 1;
5720 /* Given a basic block B which ends with a conditional and has
5721 precisely two successors, determine which of the edges is taken if
5722 the conditional is true and which is taken if the conditional is
5723 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5726 extract_true_false_edges_from_block (basic_block b,
5730 edge e = EDGE_SUCC (b, 0);
5732 if (e->flags & EDGE_TRUE_VALUE)
5735 *false_edge = EDGE_SUCC (b, 1);
5740 *true_edge = EDGE_SUCC (b, 1);
5744 struct tree_opt_pass pass_warn_function_return =
5748 execute_warn_function_return, /* execute */
5751 0, /* static_pass_number */
5753 PROP_cfg, /* properties_required */
5754 0, /* properties_provided */
5755 0, /* properties_destroyed */
5756 0, /* todo_flags_start */
5757 0, /* todo_flags_finish */
5761 /* Emit noreturn warnings. */
5764 execute_warn_function_noreturn (void)
5766 if (warn_missing_noreturn
5767 && !TREE_THIS_VOLATILE (cfun->decl)
5768 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5769 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5770 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5771 "for attribute %<noreturn%>",
5776 struct tree_opt_pass pass_warn_function_noreturn =
5780 execute_warn_function_noreturn, /* execute */
5783 0, /* static_pass_number */
5785 PROP_cfg, /* properties_required */
5786 0, /* properties_provided */
5787 0, /* properties_destroyed */
5788 0, /* todo_flags_start */
5789 0, /* todo_flags_finish */