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 *);
115 static inline void change_bb_for_stmt (tree t, basic_block bb);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block, basic_block);
119 static bool tree_can_merge_blocks_p (basic_block, basic_block);
120 static void remove_bb (basic_block);
121 static edge find_taken_edge_computed_goto (basic_block, tree);
122 static edge find_taken_edge_cond_expr (basic_block, tree);
123 static edge find_taken_edge_switch_expr (basic_block, tree);
124 static tree find_case_label_for_value (tree, tree);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status = PROFILE_ABSENT;
132 n_basic_blocks = NUM_FIXED_BLOCKS;
133 last_basic_block = NUM_FIXED_BLOCKS;
134 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
135 VEC_safe_grow (basic_block, gc, basic_block_info, initial_cfg_capacity);
136 memset (VEC_address (basic_block, basic_block_info), 0,
137 sizeof (basic_block) * initial_cfg_capacity);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
141 VEC_safe_grow (basic_block, gc, label_to_block_map, initial_cfg_capacity);
142 memset (VEC_address (basic_block, label_to_block_map),
143 0, sizeof (basic_block) * initial_cfg_capacity);
145 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
146 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
147 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
148 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
151 /*---------------------------------------------------------------------------
153 ---------------------------------------------------------------------------*/
155 /* Entry point to the CFG builder for trees. TP points to the list of
156 statements to be added to the flowgraph. */
159 build_tree_cfg (tree *tp)
161 /* Register specific tree functions. */
162 tree_register_cfg_hooks ();
164 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
166 init_empty_tree_cfg ();
168 found_computed_goto = 0;
171 /* Computed gotos are hell to deal with, especially if there are
172 lots of them with a large number of destinations. So we factor
173 them to a common computed goto location before we build the
174 edge list. After we convert back to normal form, we will un-factor
175 the computed gotos since factoring introduces an unwanted jump. */
176 if (found_computed_goto)
177 factor_computed_gotos ();
179 /* Make sure there is always at least one block, even if it's empty. */
180 if (n_basic_blocks == NUM_FIXED_BLOCKS)
181 create_empty_bb (ENTRY_BLOCK_PTR);
183 /* Adjust the size of the array. */
184 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
186 size_t old_size = VEC_length (basic_block, basic_block_info);
188 VEC_safe_grow (basic_block, gc, basic_block_info, n_basic_blocks);
189 p = VEC_address (basic_block, basic_block_info);
190 memset (&p[old_size], 0,
191 sizeof (basic_block) * (n_basic_blocks - old_size));
194 /* To speed up statement iterator walks, we first purge dead labels. */
195 cleanup_dead_labels ();
197 /* Group case nodes to reduce the number of edges.
198 We do this after cleaning up dead labels because otherwise we miss
199 a lot of obvious case merging opportunities. */
200 group_case_labels ();
202 /* Create the edges of the flowgraph. */
205 /* Debugging dumps. */
207 /* Write the flowgraph to a VCG file. */
209 int local_dump_flags;
210 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
213 tree_cfg2vcg (vcg_file);
214 dump_end (TDI_vcg, vcg_file);
218 #ifdef ENABLE_CHECKING
222 /* Dump a textual representation of the flowgraph. */
224 dump_tree_cfg (dump_file, dump_flags);
228 execute_build_cfg (void)
230 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
234 struct tree_opt_pass pass_build_cfg =
238 execute_build_cfg, /* execute */
241 0, /* static_pass_number */
242 TV_TREE_CFG, /* tv_id */
243 PROP_gimple_leh, /* properties_required */
244 PROP_cfg, /* properties_provided */
245 0, /* properties_destroyed */
246 0, /* todo_flags_start */
247 TODO_verify_stmts, /* todo_flags_finish */
251 /* Search the CFG for any computed gotos. If found, factor them to a
252 common computed goto site. Also record the location of that site so
253 that we can un-factor the gotos after we have converted back to
257 factor_computed_gotos (void)
260 tree factored_label_decl = NULL;
262 tree factored_computed_goto_label = NULL;
263 tree factored_computed_goto = NULL;
265 /* We know there are one or more computed gotos in this function.
266 Examine the last statement in each basic block to see if the block
267 ends with a computed goto. */
271 block_stmt_iterator bsi = bsi_last (bb);
276 last = bsi_stmt (bsi);
278 /* Ignore the computed goto we create when we factor the original
280 if (last == factored_computed_goto)
283 /* If the last statement is a computed goto, factor it. */
284 if (computed_goto_p (last))
288 /* The first time we find a computed goto we need to create
289 the factored goto block and the variable each original
290 computed goto will use for their goto destination. */
291 if (! factored_computed_goto)
293 basic_block new_bb = create_empty_bb (bb);
294 block_stmt_iterator new_bsi = bsi_start (new_bb);
296 /* Create the destination of the factored goto. Each original
297 computed goto will put its desired destination into this
298 variable and jump to the label we create immediately
300 var = create_tmp_var (ptr_type_node, "gotovar");
302 /* Build a label for the new block which will contain the
303 factored computed goto. */
304 factored_label_decl = create_artificial_label ();
305 factored_computed_goto_label
306 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
307 bsi_insert_after (&new_bsi, factored_computed_goto_label,
310 /* Build our new computed goto. */
311 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
312 bsi_insert_after (&new_bsi, factored_computed_goto,
316 /* Copy the original computed goto's destination into VAR. */
317 assignment = build2_gimple (GIMPLE_MODIFY_STMT,
318 var, GOTO_DESTINATION (last));
319 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
321 /* And re-vector the computed goto to the new destination. */
322 GOTO_DESTINATION (last) = factored_label_decl;
328 /* Build a flowgraph for the statement_list STMT_LIST. */
331 make_blocks (tree stmt_list)
333 tree_stmt_iterator i = tsi_start (stmt_list);
335 bool start_new_block = true;
336 bool first_stmt_of_list = true;
337 basic_block bb = ENTRY_BLOCK_PTR;
339 while (!tsi_end_p (i))
346 /* If the statement starts a new basic block or if we have determined
347 in a previous pass that we need to create a new block for STMT, do
349 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
351 if (!first_stmt_of_list)
352 stmt_list = tsi_split_statement_list_before (&i);
353 bb = create_basic_block (stmt_list, NULL, bb);
354 start_new_block = false;
357 /* Now add STMT to BB and create the subgraphs for special statement
359 set_bb_for_stmt (stmt, bb);
361 if (computed_goto_p (stmt))
362 found_computed_goto = true;
364 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
366 if (stmt_ends_bb_p (stmt))
367 start_new_block = true;
370 first_stmt_of_list = false;
375 /* Create and return a new empty basic block after bb AFTER. */
378 create_bb (void *h, void *e, basic_block after)
384 /* Create and initialize a new basic block. Since alloc_block uses
385 ggc_alloc_cleared to allocate a basic block, we do not have to
386 clear the newly allocated basic block here. */
389 bb->index = last_basic_block;
391 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
393 /* Add the new block to the linked list of blocks. */
394 link_block (bb, after);
396 /* Grow the basic block array if needed. */
397 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
399 size_t old_size = VEC_length (basic_block, basic_block_info);
400 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
402 VEC_safe_grow (basic_block, gc, basic_block_info, new_size);
403 p = VEC_address (basic_block, basic_block_info);
404 memset (&p[old_size], 0, sizeof (basic_block) * (new_size - old_size));
407 /* Add the newly created block to the array. */
408 SET_BASIC_BLOCK (last_basic_block, bb);
417 /*---------------------------------------------------------------------------
419 ---------------------------------------------------------------------------*/
421 /* Fold COND_EXPR_COND of each COND_EXPR. */
424 fold_cond_expr_cond (void)
430 tree stmt = last_stmt (bb);
433 && TREE_CODE (stmt) == COND_EXPR)
435 tree cond = fold (COND_EXPR_COND (stmt));
436 if (integer_zerop (cond))
437 COND_EXPR_COND (stmt) = boolean_false_node;
438 else if (integer_onep (cond))
439 COND_EXPR_COND (stmt) = boolean_true_node;
444 /* Join all the blocks in the flowgraph. */
450 struct omp_region *cur_region = NULL;
452 /* Create an edge from entry to the first block with executable
454 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
456 /* Traverse the basic block array placing edges. */
459 tree last = last_stmt (bb);
464 enum tree_code code = TREE_CODE (last);
468 make_goto_expr_edges (bb);
472 make_edge (bb, EXIT_BLOCK_PTR, 0);
476 make_cond_expr_edges (bb);
480 make_switch_expr_edges (bb);
484 make_eh_edges (last);
489 /* If this function receives a nonlocal goto, then we need to
490 make edges from this call site to all the nonlocal goto
492 if (tree_can_make_abnormal_goto (last))
493 make_abnormal_goto_edges (bb, true);
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);
506 case GIMPLE_MODIFY_STMT:
507 if (is_ctrl_altering_stmt (last))
509 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
510 the CALL_EXPR may have an abnormal edge. Search the RHS
511 for this case and create any required edges. */
512 if (tree_can_make_abnormal_goto (last))
513 make_abnormal_goto_edges (bb, true);
515 make_eh_edges (last);
527 cur_region = new_omp_region (bb, code, cur_region);
532 cur_region = new_omp_region (bb, code, cur_region);
537 /* In the case of an OMP_SECTION, the edge will go somewhere
538 other than the next block. This will be created later. */
539 cur_region->exit = bb;
540 fallthru = cur_region->type != OMP_SECTION;
541 cur_region = cur_region->outer;
545 cur_region->cont = bb;
546 switch (cur_region->type)
549 /* ??? Technically there should be a some sort of loopback
550 edge here, but it goes to a block that doesn't exist yet,
551 and without it, updating the ssa form would be a real
552 bear. Fortunately, we don't yet do ssa before expanding
557 /* Wire up the edges into and out of the nested sections. */
558 /* ??? Similarly wrt loopback. */
560 struct omp_region *i;
561 for (i = cur_region->inner; i ; i = i->next)
563 gcc_assert (i->type == OMP_SECTION);
564 make_edge (cur_region->entry, i->entry, 0);
565 make_edge (i->exit, bb, EDGE_FALLTHRU);
577 gcc_assert (!stmt_ends_bb_p (last));
585 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
591 /* Fold COND_EXPR_COND of each COND_EXPR. */
592 fold_cond_expr_cond ();
594 /* Clean up the graph and warn for unreachable code. */
599 /* Create the edges for a COND_EXPR starting at block BB.
600 At this point, both clauses must contain only simple gotos. */
603 make_cond_expr_edges (basic_block bb)
605 tree entry = last_stmt (bb);
606 basic_block then_bb, else_bb;
607 tree then_label, else_label;
611 gcc_assert (TREE_CODE (entry) == COND_EXPR);
613 /* Entry basic blocks for each component. */
614 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
615 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
616 then_bb = label_to_block (then_label);
617 else_bb = label_to_block (else_label);
619 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
620 #ifdef USE_MAPPED_LOCATION
621 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
623 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
625 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
628 #ifdef USE_MAPPED_LOCATION
629 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
631 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
636 /* Hashing routine for EDGE_TO_CASES. */
639 edge_to_cases_hash (const void *p)
641 edge e = ((struct edge_to_cases_elt *)p)->e;
643 /* Hash on the edge itself (which is a pointer). */
644 return htab_hash_pointer (e);
647 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
648 for equality is just a pointer comparison. */
651 edge_to_cases_eq (const void *p1, const void *p2)
653 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
654 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
659 /* Called for each element in the hash table (P) as we delete the
660 edge to cases hash table.
662 Clear all the TREE_CHAINs to prevent problems with copying of
663 SWITCH_EXPRs and structure sharing rules, then free the hash table
667 edge_to_cases_cleanup (void *p)
669 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
672 for (t = elt->case_labels; t; t = next)
674 next = TREE_CHAIN (t);
675 TREE_CHAIN (t) = NULL;
680 /* Start recording information mapping edges to case labels. */
683 start_recording_case_labels (void)
685 gcc_assert (edge_to_cases == NULL);
687 edge_to_cases = htab_create (37,
690 edge_to_cases_cleanup);
693 /* Return nonzero if we are recording information for case labels. */
696 recording_case_labels_p (void)
698 return (edge_to_cases != NULL);
701 /* Stop recording information mapping edges to case labels and
702 remove any information we have recorded. */
704 end_recording_case_labels (void)
706 htab_delete (edge_to_cases);
707 edge_to_cases = NULL;
710 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
713 record_switch_edge (edge e, tree case_label)
715 struct edge_to_cases_elt *elt;
718 /* Build a hash table element so we can see if E is already
720 elt = XNEW (struct edge_to_cases_elt);
722 elt->case_labels = case_label;
724 slot = htab_find_slot (edge_to_cases, elt, INSERT);
728 /* E was not in the hash table. Install E into the hash table. */
733 /* E was already in the hash table. Free ELT as we do not need it
737 /* Get the entry stored in the hash table. */
738 elt = (struct edge_to_cases_elt *) *slot;
740 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
741 TREE_CHAIN (case_label) = elt->case_labels;
742 elt->case_labels = case_label;
746 /* If we are inside a {start,end}_recording_cases block, then return
747 a chain of CASE_LABEL_EXPRs from T which reference E.
749 Otherwise return NULL. */
752 get_cases_for_edge (edge e, tree t)
754 struct edge_to_cases_elt elt, *elt_p;
759 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
760 chains available. Return NULL so the caller can detect this case. */
761 if (!recording_case_labels_p ())
766 elt.case_labels = NULL;
767 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
771 elt_p = (struct edge_to_cases_elt *)*slot;
772 return elt_p->case_labels;
775 /* If we did not find E in the hash table, then this must be the first
776 time we have been queried for information about E & T. Add all the
777 elements from T to the hash table then perform the query again. */
779 vec = SWITCH_LABELS (t);
780 n = TREE_VEC_LENGTH (vec);
781 for (i = 0; i < n; i++)
783 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
784 basic_block label_bb = label_to_block (lab);
785 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
790 /* Create the edges for a SWITCH_EXPR starting at block BB.
791 At this point, the switch body has been lowered and the
792 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
795 make_switch_expr_edges (basic_block bb)
797 tree entry = last_stmt (bb);
801 vec = SWITCH_LABELS (entry);
802 n = TREE_VEC_LENGTH (vec);
804 for (i = 0; i < n; ++i)
806 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
807 basic_block label_bb = label_to_block (lab);
808 make_edge (bb, label_bb, 0);
813 /* Return the basic block holding label DEST. */
816 label_to_block_fn (struct function *ifun, tree dest)
818 int uid = LABEL_DECL_UID (dest);
820 /* We would die hard when faced by an undefined label. Emit a label to
821 the very first basic block. This will hopefully make even the dataflow
822 and undefined variable warnings quite right. */
823 if ((errorcount || sorrycount) && uid < 0)
825 block_stmt_iterator bsi =
826 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
829 stmt = build1 (LABEL_EXPR, void_type_node, dest);
830 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
831 uid = LABEL_DECL_UID (dest);
833 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
834 <= (unsigned int) uid)
836 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
839 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
840 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
843 make_abnormal_goto_edges (basic_block bb, bool for_call)
845 basic_block target_bb;
846 block_stmt_iterator bsi;
848 FOR_EACH_BB (target_bb)
849 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
851 tree target = bsi_stmt (bsi);
853 if (TREE_CODE (target) != LABEL_EXPR)
856 target = LABEL_EXPR_LABEL (target);
858 /* Make an edge to every label block that has been marked as a
859 potential target for a computed goto or a non-local goto. */
860 if ((FORCED_LABEL (target) && !for_call)
861 || (DECL_NONLOCAL (target) && for_call))
863 make_edge (bb, target_bb, EDGE_ABNORMAL);
869 /* Create edges for a goto statement at block BB. */
872 make_goto_expr_edges (basic_block bb)
874 block_stmt_iterator last = bsi_last (bb);
875 tree goto_t = bsi_stmt (last);
877 /* A simple GOTO creates normal edges. */
878 if (simple_goto_p (goto_t))
880 tree dest = GOTO_DESTINATION (goto_t);
881 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
882 #ifdef USE_MAPPED_LOCATION
883 e->goto_locus = EXPR_LOCATION (goto_t);
885 e->goto_locus = EXPR_LOCUS (goto_t);
887 bsi_remove (&last, true);
891 /* A computed GOTO creates abnormal edges. */
892 make_abnormal_goto_edges (bb, false);
896 /*---------------------------------------------------------------------------
898 ---------------------------------------------------------------------------*/
900 /* Cleanup useless labels in basic blocks. This is something we wish
901 to do early because it allows us to group case labels before creating
902 the edges for the CFG, and it speeds up block statement iterators in
904 We only run this pass once, running it more than once is probably not
907 /* A map from basic block index to the leading label of that block. */
908 static tree *label_for_bb;
910 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
912 update_eh_label (struct eh_region *region)
914 tree old_label = get_eh_region_tree_label (region);
918 basic_block bb = label_to_block (old_label);
920 /* ??? After optimizing, there may be EH regions with labels
921 that have already been removed from the function body, so
922 there is no basic block for them. */
926 new_label = label_for_bb[bb->index];
927 set_eh_region_tree_label (region, new_label);
931 /* Given LABEL return the first label in the same basic block. */
933 main_block_label (tree label)
935 basic_block bb = label_to_block (label);
937 /* label_to_block possibly inserted undefined label into the chain. */
938 if (!label_for_bb[bb->index])
939 label_for_bb[bb->index] = label;
940 return label_for_bb[bb->index];
943 /* Cleanup redundant labels. This is a three-step process:
944 1) Find the leading label for each block.
945 2) Redirect all references to labels to the leading labels.
946 3) Cleanup all useless labels. */
949 cleanup_dead_labels (void)
952 label_for_bb = XCNEWVEC (tree, last_basic_block);
954 /* Find a suitable label for each block. We use the first user-defined
955 label if there is one, or otherwise just the first label we see. */
958 block_stmt_iterator i;
960 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
962 tree label, stmt = bsi_stmt (i);
964 if (TREE_CODE (stmt) != LABEL_EXPR)
967 label = LABEL_EXPR_LABEL (stmt);
969 /* If we have not yet seen a label for the current block,
970 remember this one and see if there are more labels. */
971 if (! label_for_bb[bb->index])
973 label_for_bb[bb->index] = label;
977 /* If we did see a label for the current block already, but it
978 is an artificially created label, replace it if the current
979 label is a user defined label. */
980 if (! DECL_ARTIFICIAL (label)
981 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
983 label_for_bb[bb->index] = label;
989 /* Now redirect all jumps/branches to the selected label.
990 First do so for each block ending in a control statement. */
993 tree stmt = last_stmt (bb);
997 switch (TREE_CODE (stmt))
1001 tree true_branch, false_branch;
1003 true_branch = COND_EXPR_THEN (stmt);
1004 false_branch = COND_EXPR_ELSE (stmt);
1006 GOTO_DESTINATION (true_branch)
1007 = main_block_label (GOTO_DESTINATION (true_branch));
1008 GOTO_DESTINATION (false_branch)
1009 = main_block_label (GOTO_DESTINATION (false_branch));
1017 tree vec = SWITCH_LABELS (stmt);
1018 size_t n = TREE_VEC_LENGTH (vec);
1020 /* Replace all destination labels. */
1021 for (i = 0; i < n; ++i)
1023 tree elt = TREE_VEC_ELT (vec, i);
1024 tree label = main_block_label (CASE_LABEL (elt));
1025 CASE_LABEL (elt) = label;
1030 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1031 remove them until after we've created the CFG edges. */
1033 if (! computed_goto_p (stmt))
1035 GOTO_DESTINATION (stmt)
1036 = main_block_label (GOTO_DESTINATION (stmt));
1045 for_each_eh_region (update_eh_label);
1047 /* Finally, purge dead labels. All user-defined labels and labels that
1048 can be the target of non-local gotos and labels which have their
1049 address taken are preserved. */
1052 block_stmt_iterator i;
1053 tree label_for_this_bb = label_for_bb[bb->index];
1055 if (! label_for_this_bb)
1058 for (i = bsi_start (bb); !bsi_end_p (i); )
1060 tree label, stmt = bsi_stmt (i);
1062 if (TREE_CODE (stmt) != LABEL_EXPR)
1065 label = LABEL_EXPR_LABEL (stmt);
1067 if (label == label_for_this_bb
1068 || ! DECL_ARTIFICIAL (label)
1069 || DECL_NONLOCAL (label)
1070 || FORCED_LABEL (label))
1073 bsi_remove (&i, true);
1077 free (label_for_bb);
1080 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1081 and scan the sorted vector of cases. Combine the ones jumping to the
1083 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1086 group_case_labels (void)
1092 tree stmt = last_stmt (bb);
1093 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1095 tree labels = SWITCH_LABELS (stmt);
1096 int old_size = TREE_VEC_LENGTH (labels);
1097 int i, j, new_size = old_size;
1098 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1101 /* The default label is always the last case in a switch
1102 statement after gimplification. */
1103 default_label = CASE_LABEL (default_case);
1105 /* Look for possible opportunities to merge cases.
1106 Ignore the last element of the label vector because it
1107 must be the default case. */
1109 while (i < old_size - 1)
1111 tree base_case, base_label, base_high;
1112 base_case = TREE_VEC_ELT (labels, i);
1114 gcc_assert (base_case);
1115 base_label = CASE_LABEL (base_case);
1117 /* Discard cases that have the same destination as the
1119 if (base_label == default_label)
1121 TREE_VEC_ELT (labels, i) = NULL_TREE;
1127 base_high = CASE_HIGH (base_case) ?
1128 CASE_HIGH (base_case) : CASE_LOW (base_case);
1130 /* Try to merge case labels. Break out when we reach the end
1131 of the label vector or when we cannot merge the next case
1132 label with the current one. */
1133 while (i < old_size - 1)
1135 tree merge_case = TREE_VEC_ELT (labels, i);
1136 tree merge_label = CASE_LABEL (merge_case);
1137 tree t = int_const_binop (PLUS_EXPR, base_high,
1138 integer_one_node, 1);
1140 /* Merge the cases if they jump to the same place,
1141 and their ranges are consecutive. */
1142 if (merge_label == base_label
1143 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1145 base_high = CASE_HIGH (merge_case) ?
1146 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1147 CASE_HIGH (base_case) = base_high;
1148 TREE_VEC_ELT (labels, i) = NULL_TREE;
1157 /* Compress the case labels in the label vector, and adjust the
1158 length of the vector. */
1159 for (i = 0, j = 0; i < new_size; i++)
1161 while (! TREE_VEC_ELT (labels, j))
1163 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1165 TREE_VEC_LENGTH (labels) = new_size;
1170 /* Checks whether we can merge block B into block A. */
1173 tree_can_merge_blocks_p (basic_block a, basic_block b)
1176 block_stmt_iterator bsi;
1179 if (!single_succ_p (a))
1182 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1185 if (single_succ (a) != b)
1188 if (!single_pred_p (b))
1191 if (b == EXIT_BLOCK_PTR)
1194 /* If A ends by a statement causing exceptions or something similar, we
1195 cannot merge the blocks. */
1196 stmt = last_stmt (a);
1197 if (stmt && stmt_ends_bb_p (stmt))
1200 /* Do not allow a block with only a non-local label to be merged. */
1201 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1202 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1205 /* It must be possible to eliminate all phi nodes in B. If ssa form
1206 is not up-to-date, we cannot eliminate any phis; however, if only
1207 some symbols as whole are marked for renaming, this is not a problem,
1208 as phi nodes for those symbols are irrelevant in updating anyway. */
1209 phi = phi_nodes (b);
1212 if (name_mappings_registered_p ())
1215 for (; phi; phi = PHI_CHAIN (phi))
1216 if (!is_gimple_reg (PHI_RESULT (phi))
1217 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1221 /* Do not remove user labels. */
1222 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1224 stmt = bsi_stmt (bsi);
1225 if (TREE_CODE (stmt) != LABEL_EXPR)
1227 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1231 /* Protect the loop latches. */
1233 && b->loop_father->latch == b)
1239 /* Replaces all uses of NAME by VAL. */
1242 replace_uses_by (tree name, tree val)
1244 imm_use_iterator imm_iter;
1249 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1251 if (TREE_CODE (stmt) != PHI_NODE)
1252 push_stmt_changes (&stmt);
1254 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1256 replace_exp (use, val);
1258 if (TREE_CODE (stmt) == PHI_NODE)
1260 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1261 if (e->flags & EDGE_ABNORMAL)
1263 /* This can only occur for virtual operands, since
1264 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1265 would prevent replacement. */
1266 gcc_assert (!is_gimple_reg (name));
1267 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1272 if (TREE_CODE (stmt) != PHI_NODE)
1276 fold_stmt_inplace (stmt);
1278 /* FIXME. This should go in pop_stmt_changes. */
1279 rhs = get_rhs (stmt);
1280 if (TREE_CODE (rhs) == ADDR_EXPR)
1281 recompute_tree_invariant_for_addr_expr (rhs);
1283 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1285 pop_stmt_changes (&stmt);
1289 gcc_assert (zero_imm_uses_p (name));
1291 /* Also update the trees stored in loop structures. */
1297 FOR_EACH_LOOP (li, loop, 0)
1299 substitute_in_loop_info (loop, name, val);
1304 /* Merge block B into block A. */
1307 tree_merge_blocks (basic_block a, basic_block b)
1309 block_stmt_iterator bsi;
1310 tree_stmt_iterator last;
1314 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1316 /* Remove all single-valued PHI nodes from block B of the form
1317 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1319 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1321 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1323 bool may_replace_uses = may_propagate_copy (def, use);
1325 /* In case we have loops to care about, do not propagate arguments of
1326 loop closed ssa phi nodes. */
1328 && is_gimple_reg (def)
1329 && TREE_CODE (use) == SSA_NAME
1330 && a->loop_father != b->loop_father)
1331 may_replace_uses = false;
1333 if (!may_replace_uses)
1335 gcc_assert (is_gimple_reg (def));
1337 /* Note that just emitting the copies is fine -- there is no problem
1338 with ordering of phi nodes. This is because A is the single
1339 predecessor of B, therefore results of the phi nodes cannot
1340 appear as arguments of the phi nodes. */
1341 copy = build2_gimple (GIMPLE_MODIFY_STMT, def, use);
1342 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1343 SSA_NAME_DEF_STMT (def) = copy;
1346 replace_uses_by (def, use);
1348 remove_phi_node (phi, NULL, false);
1351 /* Ensure that B follows A. */
1352 move_block_after (b, a);
1354 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1355 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1357 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1358 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1360 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1362 tree label = bsi_stmt (bsi);
1364 bsi_remove (&bsi, false);
1365 /* Now that we can thread computed gotos, we might have
1366 a situation where we have a forced label in block B
1367 However, the label at the start of block B might still be
1368 used in other ways (think about the runtime checking for
1369 Fortran assigned gotos). So we can not just delete the
1370 label. Instead we move the label to the start of block A. */
1371 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1373 block_stmt_iterator dest_bsi = bsi_start (a);
1374 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1379 change_bb_for_stmt (bsi_stmt (bsi), a);
1384 /* Merge the chains. */
1385 last = tsi_last (a->stmt_list);
1386 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1387 b->stmt_list = NULL;
1391 /* Return the one of two successors of BB that is not reachable by a
1392 reached by a complex edge, if there is one. Else, return BB. We use
1393 this in optimizations that use post-dominators for their heuristics,
1394 to catch the cases in C++ where function calls are involved. */
1397 single_noncomplex_succ (basic_block bb)
1400 if (EDGE_COUNT (bb->succs) != 2)
1403 e0 = EDGE_SUCC (bb, 0);
1404 e1 = EDGE_SUCC (bb, 1);
1405 if (e0->flags & EDGE_COMPLEX)
1407 if (e1->flags & EDGE_COMPLEX)
1414 /* Walk the function tree removing unnecessary statements.
1416 * Empty statement nodes are removed
1418 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1420 * Unnecessary COND_EXPRs are removed
1422 * Some unnecessary BIND_EXPRs are removed
1424 Clearly more work could be done. The trick is doing the analysis
1425 and removal fast enough to be a net improvement in compile times.
1427 Note that when we remove a control structure such as a COND_EXPR
1428 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1429 to ensure we eliminate all the useless code. */
1440 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1443 remove_useless_stmts_warn_notreached (tree stmt)
1445 if (EXPR_HAS_LOCATION (stmt))
1447 location_t loc = EXPR_LOCATION (stmt);
1448 if (LOCATION_LINE (loc) > 0)
1450 warning (0, "%Hwill never be executed", &loc);
1455 switch (TREE_CODE (stmt))
1457 case STATEMENT_LIST:
1459 tree_stmt_iterator i;
1460 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1461 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1467 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1469 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1471 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1475 case TRY_FINALLY_EXPR:
1476 case TRY_CATCH_EXPR:
1477 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1479 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1484 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1485 case EH_FILTER_EXPR:
1486 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1488 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1491 /* Not a live container. */
1499 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1501 tree then_clause, else_clause, cond;
1502 bool save_has_label, then_has_label, else_has_label;
1504 save_has_label = data->has_label;
1505 data->has_label = false;
1506 data->last_goto = NULL;
1508 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1510 then_has_label = data->has_label;
1511 data->has_label = false;
1512 data->last_goto = NULL;
1514 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1516 else_has_label = data->has_label;
1517 data->has_label = save_has_label | then_has_label | else_has_label;
1519 then_clause = COND_EXPR_THEN (*stmt_p);
1520 else_clause = COND_EXPR_ELSE (*stmt_p);
1521 cond = fold (COND_EXPR_COND (*stmt_p));
1523 /* If neither arm does anything at all, we can remove the whole IF. */
1524 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1526 *stmt_p = build_empty_stmt ();
1527 data->repeat = true;
1530 /* If there are no reachable statements in an arm, then we can
1531 zap the entire conditional. */
1532 else if (integer_nonzerop (cond) && !else_has_label)
1534 if (warn_notreached)
1535 remove_useless_stmts_warn_notreached (else_clause);
1536 *stmt_p = then_clause;
1537 data->repeat = true;
1539 else if (integer_zerop (cond) && !then_has_label)
1541 if (warn_notreached)
1542 remove_useless_stmts_warn_notreached (then_clause);
1543 *stmt_p = else_clause;
1544 data->repeat = true;
1547 /* Check a couple of simple things on then/else with single stmts. */
1550 tree then_stmt = expr_only (then_clause);
1551 tree else_stmt = expr_only (else_clause);
1553 /* Notice branches to a common destination. */
1554 if (then_stmt && else_stmt
1555 && TREE_CODE (then_stmt) == GOTO_EXPR
1556 && TREE_CODE (else_stmt) == GOTO_EXPR
1557 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1559 *stmt_p = then_stmt;
1560 data->repeat = true;
1563 /* If the THEN/ELSE clause merely assigns a value to a variable or
1564 parameter which is already known to contain that value, then
1565 remove the useless THEN/ELSE clause. */
1566 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1569 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1570 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1571 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1572 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1574 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1575 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1576 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1577 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1579 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1580 ? then_stmt : else_stmt);
1581 tree *location = (TREE_CODE (cond) == EQ_EXPR
1582 ? &COND_EXPR_THEN (*stmt_p)
1583 : &COND_EXPR_ELSE (*stmt_p));
1586 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1587 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1588 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1589 *location = alloc_stmt_list ();
1593 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1594 would be re-introduced during lowering. */
1595 data->last_goto = NULL;
1600 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1602 bool save_may_branch, save_may_throw;
1603 bool this_may_branch, this_may_throw;
1605 /* Collect may_branch and may_throw information for the body only. */
1606 save_may_branch = data->may_branch;
1607 save_may_throw = data->may_throw;
1608 data->may_branch = false;
1609 data->may_throw = false;
1610 data->last_goto = NULL;
1612 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1614 this_may_branch = data->may_branch;
1615 this_may_throw = data->may_throw;
1616 data->may_branch |= save_may_branch;
1617 data->may_throw |= save_may_throw;
1618 data->last_goto = NULL;
1620 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1622 /* If the body is empty, then we can emit the FINALLY block without
1623 the enclosing TRY_FINALLY_EXPR. */
1624 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1626 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1627 data->repeat = true;
1630 /* If the handler is empty, then we can emit the TRY block without
1631 the enclosing TRY_FINALLY_EXPR. */
1632 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1634 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1635 data->repeat = true;
1638 /* If the body neither throws, nor branches, then we can safely
1639 string the TRY and FINALLY blocks together. */
1640 else if (!this_may_branch && !this_may_throw)
1642 tree stmt = *stmt_p;
1643 *stmt_p = TREE_OPERAND (stmt, 0);
1644 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1645 data->repeat = true;
1651 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1653 bool save_may_throw, this_may_throw;
1654 tree_stmt_iterator i;
1657 /* Collect may_throw information for the body only. */
1658 save_may_throw = data->may_throw;
1659 data->may_throw = false;
1660 data->last_goto = NULL;
1662 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1664 this_may_throw = data->may_throw;
1665 data->may_throw = save_may_throw;
1667 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1668 if (!this_may_throw)
1670 if (warn_notreached)
1671 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1672 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1673 data->repeat = true;
1677 /* Process the catch clause specially. We may be able to tell that
1678 no exceptions propagate past this point. */
1680 this_may_throw = true;
1681 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1682 stmt = tsi_stmt (i);
1683 data->last_goto = NULL;
1685 switch (TREE_CODE (stmt))
1688 for (; !tsi_end_p (i); tsi_next (&i))
1690 stmt = tsi_stmt (i);
1691 /* If we catch all exceptions, then the body does not
1692 propagate exceptions past this point. */
1693 if (CATCH_TYPES (stmt) == NULL)
1694 this_may_throw = false;
1695 data->last_goto = NULL;
1696 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1700 case EH_FILTER_EXPR:
1701 if (EH_FILTER_MUST_NOT_THROW (stmt))
1702 this_may_throw = false;
1703 else if (EH_FILTER_TYPES (stmt) == NULL)
1704 this_may_throw = false;
1705 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1709 /* Otherwise this is a cleanup. */
1710 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1712 /* If the cleanup is empty, then we can emit the TRY block without
1713 the enclosing TRY_CATCH_EXPR. */
1714 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1716 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1717 data->repeat = true;
1721 data->may_throw |= this_may_throw;
1726 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1730 /* First remove anything underneath the BIND_EXPR. */
1731 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1733 /* If the BIND_EXPR has no variables, then we can pull everything
1734 up one level and remove the BIND_EXPR, unless this is the toplevel
1735 BIND_EXPR for the current function or an inlined function.
1737 When this situation occurs we will want to apply this
1738 optimization again. */
1739 block = BIND_EXPR_BLOCK (*stmt_p);
1740 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1741 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1743 || ! BLOCK_ABSTRACT_ORIGIN (block)
1744 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1747 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1748 data->repeat = true;
1754 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1756 tree dest = GOTO_DESTINATION (*stmt_p);
1758 data->may_branch = true;
1759 data->last_goto = NULL;
1761 /* Record the last goto expr, so that we can delete it if unnecessary. */
1762 if (TREE_CODE (dest) == LABEL_DECL)
1763 data->last_goto = stmt_p;
1768 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1770 tree label = LABEL_EXPR_LABEL (*stmt_p);
1772 data->has_label = true;
1774 /* We do want to jump across non-local label receiver code. */
1775 if (DECL_NONLOCAL (label))
1776 data->last_goto = NULL;
1778 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1780 *data->last_goto = build_empty_stmt ();
1781 data->repeat = true;
1784 /* ??? Add something here to delete unused labels. */
1788 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1789 decl. This allows us to eliminate redundant or useless
1790 calls to "const" functions.
1792 Gimplifier already does the same operation, but we may notice functions
1793 being const and pure once their calls has been gimplified, so we need
1794 to update the flag. */
1797 update_call_expr_flags (tree call)
1799 tree decl = get_callee_fndecl (call);
1802 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1803 TREE_SIDE_EFFECTS (call) = 0;
1804 if (TREE_NOTHROW (decl))
1805 TREE_NOTHROW (call) = 1;
1809 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1812 notice_special_calls (tree t)
1814 int flags = call_expr_flags (t);
1816 if (flags & ECF_MAY_BE_ALLOCA)
1817 current_function_calls_alloca = true;
1818 if (flags & ECF_RETURNS_TWICE)
1819 current_function_calls_setjmp = true;
1823 /* Clear flags set by notice_special_calls. Used by dead code removal
1824 to update the flags. */
1827 clear_special_calls (void)
1829 current_function_calls_alloca = false;
1830 current_function_calls_setjmp = false;
1835 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1839 switch (TREE_CODE (t))
1842 remove_useless_stmts_cond (tp, data);
1845 case TRY_FINALLY_EXPR:
1846 remove_useless_stmts_tf (tp, data);
1849 case TRY_CATCH_EXPR:
1850 remove_useless_stmts_tc (tp, data);
1854 remove_useless_stmts_bind (tp, data);
1858 remove_useless_stmts_goto (tp, data);
1862 remove_useless_stmts_label (tp, data);
1867 data->last_goto = NULL;
1868 data->may_branch = true;
1873 data->last_goto = NULL;
1874 notice_special_calls (t);
1875 update_call_expr_flags (t);
1876 if (tree_could_throw_p (t))
1877 data->may_throw = true;
1883 case GIMPLE_MODIFY_STMT:
1884 data->last_goto = NULL;
1886 op = get_call_expr_in (t);
1889 update_call_expr_flags (op);
1890 notice_special_calls (op);
1892 if (tree_could_throw_p (t))
1893 data->may_throw = true;
1896 case STATEMENT_LIST:
1898 tree_stmt_iterator i = tsi_start (t);
1899 while (!tsi_end_p (i))
1902 if (IS_EMPTY_STMT (t))
1908 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1911 if (TREE_CODE (t) == STATEMENT_LIST)
1913 tsi_link_before (&i, t, TSI_SAME_STMT);
1923 data->last_goto = NULL;
1927 data->last_goto = NULL;
1933 remove_useless_stmts (void)
1935 struct rus_data data;
1937 clear_special_calls ();
1941 memset (&data, 0, sizeof (data));
1942 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1944 while (data.repeat);
1949 struct tree_opt_pass pass_remove_useless_stmts =
1951 "useless", /* name */
1953 remove_useless_stmts, /* execute */
1956 0, /* static_pass_number */
1958 PROP_gimple_any, /* properties_required */
1959 0, /* properties_provided */
1960 0, /* properties_destroyed */
1961 0, /* todo_flags_start */
1962 TODO_dump_func, /* todo_flags_finish */
1966 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1969 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1973 /* Since this block is no longer reachable, we can just delete all
1974 of its PHI nodes. */
1975 phi = phi_nodes (bb);
1978 tree next = PHI_CHAIN (phi);
1979 remove_phi_node (phi, NULL_TREE, true);
1983 /* Remove edges to BB's successors. */
1984 while (EDGE_COUNT (bb->succs) > 0)
1985 remove_edge (EDGE_SUCC (bb, 0));
1989 /* Remove statements of basic block BB. */
1992 remove_bb (basic_block bb)
1994 block_stmt_iterator i;
1995 #ifdef USE_MAPPED_LOCATION
1996 source_location loc = UNKNOWN_LOCATION;
1998 source_locus loc = 0;
2003 fprintf (dump_file, "Removing basic block %d\n", bb->index);
2004 if (dump_flags & TDF_DETAILS)
2006 dump_bb (bb, dump_file, 0);
2007 fprintf (dump_file, "\n");
2013 struct loop *loop = bb->loop_father;
2015 /* If a loop gets removed, clean up the information associated
2017 if (loop->latch == bb
2018 || loop->header == bb)
2019 free_numbers_of_iterations_estimates_loop (loop);
2022 /* Remove all the instructions in the block. */
2023 for (i = bsi_start (bb); !bsi_end_p (i);)
2025 tree stmt = bsi_stmt (i);
2026 if (TREE_CODE (stmt) == LABEL_EXPR
2027 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2028 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2031 block_stmt_iterator new_bsi;
2033 /* A non-reachable non-local label may still be referenced.
2034 But it no longer needs to carry the extra semantics of
2036 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2038 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2039 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2042 new_bb = bb->prev_bb;
2043 new_bsi = bsi_start (new_bb);
2044 bsi_remove (&i, false);
2045 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2049 /* Release SSA definitions if we are in SSA. Note that we
2050 may be called when not in SSA. For example,
2051 final_cleanup calls this function via
2052 cleanup_tree_cfg. */
2053 if (gimple_in_ssa_p (cfun))
2054 release_defs (stmt);
2056 bsi_remove (&i, true);
2059 /* Don't warn for removed gotos. Gotos are often removed due to
2060 jump threading, thus resulting in bogus warnings. Not great,
2061 since this way we lose warnings for gotos in the original
2062 program that are indeed unreachable. */
2063 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2065 #ifdef USE_MAPPED_LOCATION
2066 if (EXPR_HAS_LOCATION (stmt))
2067 loc = EXPR_LOCATION (stmt);
2070 t = EXPR_LOCUS (stmt);
2071 if (t && LOCATION_LINE (*t) > 0)
2077 /* If requested, give a warning that the first statement in the
2078 block is unreachable. We walk statements backwards in the
2079 loop above, so the last statement we process is the first statement
2081 #ifdef USE_MAPPED_LOCATION
2082 if (loc > BUILTINS_LOCATION)
2083 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2086 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2089 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2093 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2094 predicate VAL, return the edge that will be taken out of the block.
2095 If VAL does not match a unique edge, NULL is returned. */
2098 find_taken_edge (basic_block bb, tree val)
2102 stmt = last_stmt (bb);
2105 gcc_assert (is_ctrl_stmt (stmt));
2108 if (! is_gimple_min_invariant (val))
2111 if (TREE_CODE (stmt) == COND_EXPR)
2112 return find_taken_edge_cond_expr (bb, val);
2114 if (TREE_CODE (stmt) == SWITCH_EXPR)
2115 return find_taken_edge_switch_expr (bb, val);
2117 if (computed_goto_p (stmt))
2118 return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
2123 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2124 statement, determine which of the outgoing edges will be taken out of the
2125 block. Return NULL if either edge may be taken. */
2128 find_taken_edge_computed_goto (basic_block bb, tree val)
2133 dest = label_to_block (val);
2136 e = find_edge (bb, dest);
2137 gcc_assert (e != NULL);
2143 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2144 statement, determine which of the two edges will be taken out of the
2145 block. Return NULL if either edge may be taken. */
2148 find_taken_edge_cond_expr (basic_block bb, tree val)
2150 edge true_edge, false_edge;
2152 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2154 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2155 return (zero_p (val) ? false_edge : true_edge);
2158 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2159 statement, determine which edge will be taken out of the block. Return
2160 NULL if any edge may be taken. */
2163 find_taken_edge_switch_expr (basic_block bb, tree val)
2165 tree switch_expr, taken_case;
2166 basic_block dest_bb;
2169 switch_expr = last_stmt (bb);
2170 taken_case = find_case_label_for_value (switch_expr, val);
2171 dest_bb = label_to_block (CASE_LABEL (taken_case));
2173 e = find_edge (bb, dest_bb);
2179 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2180 We can make optimal use here of the fact that the case labels are
2181 sorted: We can do a binary search for a case matching VAL. */
2184 find_case_label_for_value (tree switch_expr, tree val)
2186 tree vec = SWITCH_LABELS (switch_expr);
2187 size_t low, high, n = TREE_VEC_LENGTH (vec);
2188 tree default_case = TREE_VEC_ELT (vec, n - 1);
2190 for (low = -1, high = n - 1; high - low > 1; )
2192 size_t i = (high + low) / 2;
2193 tree t = TREE_VEC_ELT (vec, i);
2196 /* Cache the result of comparing CASE_LOW and val. */
2197 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2204 if (CASE_HIGH (t) == NULL)
2206 /* A singe-valued case label. */
2212 /* A case range. We can only handle integer ranges. */
2213 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2218 return default_case;
2224 /*---------------------------------------------------------------------------
2226 ---------------------------------------------------------------------------*/
2228 /* Dump tree-specific information of block BB to file OUTF. */
2231 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2233 dump_generic_bb (outf, bb, indent, TDF_VOPS);
2237 /* Dump a basic block on stderr. */
2240 debug_tree_bb (basic_block bb)
2242 dump_bb (bb, stderr, 0);
2246 /* Dump basic block with index N on stderr. */
2249 debug_tree_bb_n (int n)
2251 debug_tree_bb (BASIC_BLOCK (n));
2252 return BASIC_BLOCK (n);
2256 /* Dump the CFG on stderr.
2258 FLAGS are the same used by the tree dumping functions
2259 (see TDF_* in tree-pass.h). */
2262 debug_tree_cfg (int flags)
2264 dump_tree_cfg (stderr, flags);
2268 /* Dump the program showing basic block boundaries on the given FILE.
2270 FLAGS are the same used by the tree dumping functions (see TDF_* in
2274 dump_tree_cfg (FILE *file, int flags)
2276 if (flags & TDF_DETAILS)
2278 const char *funcname
2279 = lang_hooks.decl_printable_name (current_function_decl, 2);
2282 fprintf (file, ";; Function %s\n\n", funcname);
2283 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2284 n_basic_blocks, n_edges, last_basic_block);
2286 brief_dump_cfg (file);
2287 fprintf (file, "\n");
2290 if (flags & TDF_STATS)
2291 dump_cfg_stats (file);
2293 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2297 /* Dump CFG statistics on FILE. */
2300 dump_cfg_stats (FILE *file)
2302 static long max_num_merged_labels = 0;
2303 unsigned long size, total = 0;
2306 const char * const fmt_str = "%-30s%-13s%12s\n";
2307 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2308 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2309 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2310 const char *funcname
2311 = lang_hooks.decl_printable_name (current_function_decl, 2);
2314 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2316 fprintf (file, "---------------------------------------------------------\n");
2317 fprintf (file, fmt_str, "", " Number of ", "Memory");
2318 fprintf (file, fmt_str, "", " instances ", "used ");
2319 fprintf (file, "---------------------------------------------------------\n");
2321 size = n_basic_blocks * sizeof (struct basic_block_def);
2323 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2324 SCALE (size), LABEL (size));
2328 num_edges += EDGE_COUNT (bb->succs);
2329 size = num_edges * sizeof (struct edge_def);
2331 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2333 fprintf (file, "---------------------------------------------------------\n");
2334 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2336 fprintf (file, "---------------------------------------------------------\n");
2337 fprintf (file, "\n");
2339 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2340 max_num_merged_labels = cfg_stats.num_merged_labels;
2342 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2343 cfg_stats.num_merged_labels, max_num_merged_labels);
2345 fprintf (file, "\n");
2349 /* Dump CFG statistics on stderr. Keep extern so that it's always
2350 linked in the final executable. */
2353 debug_cfg_stats (void)
2355 dump_cfg_stats (stderr);
2359 /* Dump the flowgraph to a .vcg FILE. */
2362 tree_cfg2vcg (FILE *file)
2367 const char *funcname
2368 = lang_hooks.decl_printable_name (current_function_decl, 2);
2370 /* Write the file header. */
2371 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2372 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2373 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2375 /* Write blocks and edges. */
2376 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2378 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2381 if (e->flags & EDGE_FAKE)
2382 fprintf (file, " linestyle: dotted priority: 10");
2384 fprintf (file, " linestyle: solid priority: 100");
2386 fprintf (file, " }\n");
2392 enum tree_code head_code, end_code;
2393 const char *head_name, *end_name;
2396 tree first = first_stmt (bb);
2397 tree last = last_stmt (bb);
2401 head_code = TREE_CODE (first);
2402 head_name = tree_code_name[head_code];
2403 head_line = get_lineno (first);
2406 head_name = "no-statement";
2410 end_code = TREE_CODE (last);
2411 end_name = tree_code_name[end_code];
2412 end_line = get_lineno (last);
2415 end_name = "no-statement";
2417 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2418 bb->index, bb->index, head_name, head_line, end_name,
2421 FOR_EACH_EDGE (e, ei, bb->succs)
2423 if (e->dest == EXIT_BLOCK_PTR)
2424 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2426 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2428 if (e->flags & EDGE_FAKE)
2429 fprintf (file, " priority: 10 linestyle: dotted");
2431 fprintf (file, " priority: 100 linestyle: solid");
2433 fprintf (file, " }\n");
2436 if (bb->next_bb != EXIT_BLOCK_PTR)
2440 fputs ("}\n\n", file);
2445 /*---------------------------------------------------------------------------
2446 Miscellaneous helpers
2447 ---------------------------------------------------------------------------*/
2449 /* Return true if T represents a stmt that always transfers control. */
2452 is_ctrl_stmt (tree t)
2454 return (TREE_CODE (t) == COND_EXPR
2455 || TREE_CODE (t) == SWITCH_EXPR
2456 || TREE_CODE (t) == GOTO_EXPR
2457 || TREE_CODE (t) == RETURN_EXPR
2458 || TREE_CODE (t) == RESX_EXPR);
2462 /* Return true if T is a statement that may alter the flow of control
2463 (e.g., a call to a non-returning function). */
2466 is_ctrl_altering_stmt (tree t)
2471 call = get_call_expr_in (t);
2474 /* A non-pure/const CALL_EXPR alters flow control if the current
2475 function has nonlocal labels. */
2476 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2479 /* A CALL_EXPR also alters control flow if it does not return. */
2480 if (call_expr_flags (call) & ECF_NORETURN)
2484 /* OpenMP directives alter control flow. */
2485 if (OMP_DIRECTIVE_P (t))
2488 /* If a statement can throw, it alters control flow. */
2489 return tree_can_throw_internal (t);
2493 /* Return true if T is a computed goto. */
2496 computed_goto_p (tree t)
2498 return (TREE_CODE (t) == GOTO_EXPR
2499 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2503 /* Return true if T is a simple local goto. */
2506 simple_goto_p (tree t)
2508 return (TREE_CODE (t) == GOTO_EXPR
2509 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2513 /* Return true if T can make an abnormal transfer of control flow.
2514 Transfers of control flow associated with EH are excluded. */
2517 tree_can_make_abnormal_goto (tree t)
2519 if (computed_goto_p (t))
2521 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2522 t = GIMPLE_STMT_OPERAND (t, 1);
2523 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2524 t = TREE_OPERAND (t, 0);
2525 if (TREE_CODE (t) == CALL_EXPR)
2526 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2531 /* Return true if T should start a new basic block. PREV_T is the
2532 statement preceding T. It is used when T is a label or a case label.
2533 Labels should only start a new basic block if their previous statement
2534 wasn't a label. Otherwise, sequence of labels would generate
2535 unnecessary basic blocks that only contain a single label. */
2538 stmt_starts_bb_p (tree t, tree prev_t)
2543 /* LABEL_EXPRs start a new basic block only if the preceding
2544 statement wasn't a label of the same type. This prevents the
2545 creation of consecutive blocks that have nothing but a single
2547 if (TREE_CODE (t) == LABEL_EXPR)
2549 /* Nonlocal and computed GOTO targets always start a new block. */
2550 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2551 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2554 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2556 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2559 cfg_stats.num_merged_labels++;
2570 /* Return true if T should end a basic block. */
2573 stmt_ends_bb_p (tree t)
2575 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2579 /* Add gotos that used to be represented implicitly in the CFG. */
2582 disband_implicit_edges (void)
2585 block_stmt_iterator last;
2592 last = bsi_last (bb);
2593 stmt = last_stmt (bb);
2595 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2597 /* Remove superfluous gotos from COND_EXPR branches. Moved
2598 from cfg_remove_useless_stmts here since it violates the
2599 invariants for tree--cfg correspondence and thus fits better
2600 here where we do it anyway. */
2601 e = find_edge (bb, bb->next_bb);
2604 if (e->flags & EDGE_TRUE_VALUE)
2605 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2606 else if (e->flags & EDGE_FALSE_VALUE)
2607 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2610 e->flags |= EDGE_FALLTHRU;
2616 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2618 /* Remove the RETURN_EXPR if we may fall though to the exit
2620 gcc_assert (single_succ_p (bb));
2621 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2623 if (bb->next_bb == EXIT_BLOCK_PTR
2624 && !TREE_OPERAND (stmt, 0))
2626 bsi_remove (&last, true);
2627 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2632 /* There can be no fallthru edge if the last statement is a control
2634 if (stmt && is_ctrl_stmt (stmt))
2637 /* Find a fallthru edge and emit the goto if necessary. */
2638 FOR_EACH_EDGE (e, ei, bb->succs)
2639 if (e->flags & EDGE_FALLTHRU)
2642 if (!e || e->dest == bb->next_bb)
2645 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2646 label = tree_block_label (e->dest);
2648 stmt = build1 (GOTO_EXPR, void_type_node, label);
2649 #ifdef USE_MAPPED_LOCATION
2650 SET_EXPR_LOCATION (stmt, e->goto_locus);
2652 SET_EXPR_LOCUS (stmt, e->goto_locus);
2654 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2655 e->flags &= ~EDGE_FALLTHRU;
2659 /* Remove block annotations and other datastructures. */
2662 delete_tree_cfg_annotations (void)
2664 label_to_block_map = NULL;
2668 /* Return the first statement in basic block BB. */
2671 first_stmt (basic_block bb)
2673 block_stmt_iterator i = bsi_start (bb);
2674 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2678 /* Return the last statement in basic block BB. */
2681 last_stmt (basic_block bb)
2683 block_stmt_iterator b = bsi_last (bb);
2684 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2688 /* Return a pointer to the last statement in block BB. */
2691 last_stmt_ptr (basic_block bb)
2693 block_stmt_iterator last = bsi_last (bb);
2694 return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL;
2698 /* Return the last statement of an otherwise empty block. Return NULL
2699 if the block is totally empty, or if it contains more than one
2703 last_and_only_stmt (basic_block bb)
2705 block_stmt_iterator i = bsi_last (bb);
2711 last = bsi_stmt (i);
2716 /* Empty statements should no longer appear in the instruction stream.
2717 Everything that might have appeared before should be deleted by
2718 remove_useless_stmts, and the optimizers should just bsi_remove
2719 instead of smashing with build_empty_stmt.
2721 Thus the only thing that should appear here in a block containing
2722 one executable statement is a label. */
2723 prev = bsi_stmt (i);
2724 if (TREE_CODE (prev) == LABEL_EXPR)
2731 /* Mark BB as the basic block holding statement T. */
2734 set_bb_for_stmt (tree t, basic_block bb)
2736 if (TREE_CODE (t) == PHI_NODE)
2738 else if (TREE_CODE (t) == STATEMENT_LIST)
2740 tree_stmt_iterator i;
2741 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2742 set_bb_for_stmt (tsi_stmt (i), bb);
2746 stmt_ann_t ann = get_stmt_ann (t);
2749 /* If the statement is a label, add the label to block-to-labels map
2750 so that we can speed up edge creation for GOTO_EXPRs. */
2751 if (TREE_CODE (t) == LABEL_EXPR)
2755 t = LABEL_EXPR_LABEL (t);
2756 uid = LABEL_DECL_UID (t);
2759 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2760 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2761 if (old_len <= (unsigned) uid)
2764 unsigned new_len = 3 * uid / 2;
2766 VEC_safe_grow (basic_block, gc, label_to_block_map,
2768 addr = VEC_address (basic_block, label_to_block_map);
2769 memset (&addr[old_len],
2770 0, sizeof (basic_block) * (new_len - old_len));
2774 /* We're moving an existing label. Make sure that we've
2775 removed it from the old block. */
2777 || !VEC_index (basic_block, label_to_block_map, uid));
2778 VEC_replace (basic_block, label_to_block_map, uid, bb);
2783 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2784 from one basic block to another.
2785 For BB splitting we can run into quadratic case, so performance is quite
2786 important and knowing that the tables are big enough, change_bb_for_stmt
2787 can inline as leaf function. */
2789 change_bb_for_stmt (tree t, basic_block bb)
2791 get_stmt_ann (t)->bb = bb;
2792 if (TREE_CODE (t) == LABEL_EXPR)
2793 VEC_replace (basic_block, label_to_block_map,
2794 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2797 /* Finds iterator for STMT. */
2799 extern block_stmt_iterator
2800 bsi_for_stmt (tree stmt)
2802 block_stmt_iterator bsi;
2804 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2805 if (bsi_stmt (bsi) == stmt)
2811 /* Mark statement T as modified, and update it. */
2813 update_modified_stmts (tree t)
2815 if (TREE_CODE (t) == STATEMENT_LIST)
2817 tree_stmt_iterator i;
2819 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2821 stmt = tsi_stmt (i);
2822 update_stmt_if_modified (stmt);
2826 update_stmt_if_modified (t);
2829 /* Insert statement (or statement list) T before the statement
2830 pointed-to by iterator I. M specifies how to update iterator I
2831 after insertion (see enum bsi_iterator_update). */
2834 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2836 set_bb_for_stmt (t, i->bb);
2837 update_modified_stmts (t);
2838 tsi_link_before (&i->tsi, t, m);
2842 /* Insert statement (or statement list) T after the statement
2843 pointed-to by iterator I. M specifies how to update iterator I
2844 after insertion (see enum bsi_iterator_update). */
2847 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2849 set_bb_for_stmt (t, i->bb);
2850 update_modified_stmts (t);
2851 tsi_link_after (&i->tsi, t, m);
2855 /* Remove the statement pointed to by iterator I. The iterator is updated
2856 to the next statement.
2858 When REMOVE_EH_INFO is true we remove the statement pointed to by
2859 iterator I from the EH tables. Otherwise we do not modify the EH
2862 Generally, REMOVE_EH_INFO should be true when the statement is going to
2863 be removed from the IL and not reinserted elsewhere. */
2866 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2868 tree t = bsi_stmt (*i);
2869 set_bb_for_stmt (t, NULL);
2870 delink_stmt_imm_use (t);
2871 tsi_delink (&i->tsi);
2872 mark_stmt_modified (t);
2874 remove_stmt_from_eh_region (t);
2878 /* Move the statement at FROM so it comes right after the statement at TO. */
2881 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2883 tree stmt = bsi_stmt (*from);
2884 bsi_remove (from, false);
2885 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2889 /* Move the statement at FROM so it comes right before the statement at TO. */
2892 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2894 tree stmt = bsi_stmt (*from);
2895 bsi_remove (from, false);
2896 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2900 /* Move the statement at FROM to the end of basic block BB. */
2903 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2905 block_stmt_iterator last = bsi_last (bb);
2907 /* Have to check bsi_end_p because it could be an empty block. */
2908 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2909 bsi_move_before (from, &last);
2911 bsi_move_after (from, &last);
2915 /* Replace the contents of the statement pointed to by iterator BSI
2916 with STMT. If UPDATE_EH_INFO is true, the exception handling
2917 information of the original statement is moved to the new statement. */
2920 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2923 tree orig_stmt = bsi_stmt (*bsi);
2925 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2926 set_bb_for_stmt (stmt, bsi->bb);
2928 /* Preserve EH region information from the original statement, if
2929 requested by the caller. */
2932 eh_region = lookup_stmt_eh_region (orig_stmt);
2935 remove_stmt_from_eh_region (orig_stmt);
2936 add_stmt_to_eh_region (stmt, eh_region);
2940 delink_stmt_imm_use (orig_stmt);
2941 *bsi_stmt_ptr (*bsi) = stmt;
2942 mark_stmt_modified (stmt);
2943 update_modified_stmts (stmt);
2947 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2948 is made to place the statement in an existing basic block, but
2949 sometimes that isn't possible. When it isn't possible, the edge is
2950 split and the statement is added to the new block.
2952 In all cases, the returned *BSI points to the correct location. The
2953 return value is true if insertion should be done after the location,
2954 or false if it should be done before the location. If new basic block
2955 has to be created, it is stored in *NEW_BB. */
2958 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2959 basic_block *new_bb)
2961 basic_block dest, src;
2967 /* If the destination has one predecessor which has no PHI nodes,
2968 insert there. Except for the exit block.
2970 The requirement for no PHI nodes could be relaxed. Basically we
2971 would have to examine the PHIs to prove that none of them used
2972 the value set by the statement we want to insert on E. That
2973 hardly seems worth the effort. */
2974 if (single_pred_p (dest)
2975 && ! phi_nodes (dest)
2976 && dest != EXIT_BLOCK_PTR)
2978 *bsi = bsi_start (dest);
2979 if (bsi_end_p (*bsi))
2982 /* Make sure we insert after any leading labels. */
2983 tmp = bsi_stmt (*bsi);
2984 while (TREE_CODE (tmp) == LABEL_EXPR)
2987 if (bsi_end_p (*bsi))
2989 tmp = bsi_stmt (*bsi);
2992 if (bsi_end_p (*bsi))
2994 *bsi = bsi_last (dest);
3001 /* If the source has one successor, the edge is not abnormal and
3002 the last statement does not end a basic block, insert there.
3003 Except for the entry block. */
3005 if ((e->flags & EDGE_ABNORMAL) == 0
3006 && single_succ_p (src)
3007 && src != ENTRY_BLOCK_PTR)
3009 *bsi = bsi_last (src);
3010 if (bsi_end_p (*bsi))
3013 tmp = bsi_stmt (*bsi);
3014 if (!stmt_ends_bb_p (tmp))
3017 /* Insert code just before returning the value. We may need to decompose
3018 the return in the case it contains non-trivial operand. */
3019 if (TREE_CODE (tmp) == RETURN_EXPR)
3021 tree op = TREE_OPERAND (tmp, 0);
3022 if (op && !is_gimple_val (op))
3024 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
3025 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3026 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
3033 /* Otherwise, create a new basic block, and split this edge. */
3034 dest = split_edge (e);
3037 e = single_pred_edge (dest);
3042 /* This routine will commit all pending edge insertions, creating any new
3043 basic blocks which are necessary. */
3046 bsi_commit_edge_inserts (void)
3052 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3055 FOR_EACH_EDGE (e, ei, bb->succs)
3056 bsi_commit_one_edge_insert (e, NULL);
3060 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3061 to this block, otherwise set it to NULL. */
3064 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3068 if (PENDING_STMT (e))
3070 block_stmt_iterator bsi;
3071 tree stmt = PENDING_STMT (e);
3073 PENDING_STMT (e) = NULL_TREE;
3075 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3076 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3078 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3083 /* Add STMT to the pending list of edge E. No actual insertion is
3084 made until a call to bsi_commit_edge_inserts () is made. */
3087 bsi_insert_on_edge (edge e, tree stmt)
3089 append_to_statement_list (stmt, &PENDING_STMT (e));
3092 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3093 block has to be created, it is returned. */
3096 bsi_insert_on_edge_immediate (edge e, tree stmt)
3098 block_stmt_iterator bsi;
3099 basic_block new_bb = NULL;
3101 gcc_assert (!PENDING_STMT (e));
3103 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3104 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3106 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3111 /*---------------------------------------------------------------------------
3112 Tree specific functions for CFG manipulation
3113 ---------------------------------------------------------------------------*/
3115 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3118 reinstall_phi_args (edge new_edge, edge old_edge)
3122 if (!PENDING_STMT (old_edge))
3125 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3127 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3129 tree result = TREE_PURPOSE (var);
3130 tree arg = TREE_VALUE (var);
3132 gcc_assert (result == PHI_RESULT (phi));
3134 add_phi_arg (phi, arg, new_edge);
3137 PENDING_STMT (old_edge) = NULL;
3140 /* Returns the basic block after which the new basic block created
3141 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3142 near its "logical" location. This is of most help to humans looking
3143 at debugging dumps. */
3146 split_edge_bb_loc (edge edge_in)
3148 basic_block dest = edge_in->dest;
3150 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3151 return edge_in->src;
3153 return dest->prev_bb;
3156 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3157 Abort on abnormal edges. */
3160 tree_split_edge (edge edge_in)
3162 basic_block new_bb, after_bb, dest;
3165 /* Abnormal edges cannot be split. */
3166 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3168 dest = edge_in->dest;
3170 after_bb = split_edge_bb_loc (edge_in);
3172 new_bb = create_empty_bb (after_bb);
3173 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3174 new_bb->count = edge_in->count;
3175 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3176 new_edge->probability = REG_BR_PROB_BASE;
3177 new_edge->count = edge_in->count;
3179 e = redirect_edge_and_branch (edge_in, new_bb);
3181 reinstall_phi_args (new_edge, e);
3187 /* Return true when BB has label LABEL in it. */
3190 has_label_p (basic_block bb, tree label)
3192 block_stmt_iterator bsi;
3194 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3196 tree stmt = bsi_stmt (bsi);
3198 if (TREE_CODE (stmt) != LABEL_EXPR)
3200 if (LABEL_EXPR_LABEL (stmt) == label)
3207 /* Callback for walk_tree, check that all elements with address taken are
3208 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3209 inside a PHI node. */
3212 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3215 bool in_phi = (data != NULL);
3220 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3221 #define CHECK_OP(N, MSG) \
3222 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3223 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3225 switch (TREE_CODE (t))
3228 if (SSA_NAME_IN_FREE_LIST (t))
3230 error ("SSA name in freelist but still referenced");
3236 x = fold (ASSERT_EXPR_COND (t));
3237 if (x == boolean_false_node)
3239 error ("ASSERT_EXPR with an always-false condition");
3247 case GIMPLE_MODIFY_STMT:
3248 x = GIMPLE_STMT_OPERAND (t, 0);
3249 if (TREE_CODE (x) == BIT_FIELD_REF
3250 && is_gimple_reg (TREE_OPERAND (x, 0)))
3252 error ("GIMPLE register modified with BIT_FIELD_REF");
3261 bool old_side_effects;
3264 bool new_side_effects;
3266 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3267 dead PHIs that take the address of something. But if the PHI
3268 result is dead, the fact that it takes the address of anything
3269 is irrelevant. Because we can not tell from here if a PHI result
3270 is dead, we just skip this check for PHIs altogether. This means
3271 we may be missing "valid" checks, but what can you do?
3272 This was PR19217. */
3276 old_invariant = TREE_INVARIANT (t);
3277 old_constant = TREE_CONSTANT (t);
3278 old_side_effects = TREE_SIDE_EFFECTS (t);
3280 recompute_tree_invariant_for_addr_expr (t);
3281 new_invariant = TREE_INVARIANT (t);
3282 new_side_effects = TREE_SIDE_EFFECTS (t);
3283 new_constant = TREE_CONSTANT (t);
3285 if (old_invariant != new_invariant)
3287 error ("invariant not recomputed when ADDR_EXPR changed");
3291 if (old_constant != new_constant)
3293 error ("constant not recomputed when ADDR_EXPR changed");
3296 if (old_side_effects != new_side_effects)
3298 error ("side effects not recomputed when ADDR_EXPR changed");
3302 /* Skip any references (they will be checked when we recurse down the
3303 tree) and ensure that any variable used as a prefix is marked
3305 for (x = TREE_OPERAND (t, 0);
3306 handled_component_p (x);
3307 x = TREE_OPERAND (x, 0))
3310 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3312 if (!TREE_ADDRESSABLE (x))
3314 error ("address taken, but ADDRESSABLE bit not set");
3321 x = COND_EXPR_COND (t);
3322 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3324 error ("non-boolean used in condition");
3327 if (!is_gimple_condexpr (x))
3329 error ("invalid conditional operand");
3336 case FIX_TRUNC_EXPR:
3341 case NON_LVALUE_EXPR:
3342 case TRUTH_NOT_EXPR:
3343 CHECK_OP (0, "invalid operand to unary operator");
3350 case ARRAY_RANGE_REF:
3352 case VIEW_CONVERT_EXPR:
3353 /* We have a nest of references. Verify that each of the operands
3354 that determine where to reference is either a constant or a variable,
3355 verify that the base is valid, and then show we've already checked
3357 while (handled_component_p (t))
3359 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3360 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3361 else if (TREE_CODE (t) == ARRAY_REF
3362 || TREE_CODE (t) == ARRAY_RANGE_REF)
3364 CHECK_OP (1, "invalid array index");
3365 if (TREE_OPERAND (t, 2))
3366 CHECK_OP (2, "invalid array lower bound");
3367 if (TREE_OPERAND (t, 3))
3368 CHECK_OP (3, "invalid array stride");
3370 else if (TREE_CODE (t) == BIT_FIELD_REF)
3372 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3373 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3376 t = TREE_OPERAND (t, 0);
3379 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3381 error ("invalid reference prefix");
3393 case UNORDERED_EXPR:
3404 case TRUNC_DIV_EXPR:
3406 case FLOOR_DIV_EXPR:
3407 case ROUND_DIV_EXPR:
3408 case TRUNC_MOD_EXPR:
3410 case FLOOR_MOD_EXPR:
3411 case ROUND_MOD_EXPR:
3413 case EXACT_DIV_EXPR:
3423 CHECK_OP (0, "invalid operand to binary operator");
3424 CHECK_OP (1, "invalid operand to binary operator");
3428 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3441 /* Verify STMT, return true if STMT is not in GIMPLE form.
3442 TODO: Implement type checking. */
3445 verify_stmt (tree stmt, bool last_in_block)
3449 if (OMP_DIRECTIVE_P (stmt))
3451 /* OpenMP directives are validated by the FE and never operated
3452 on by the optimizers. Furthermore, OMP_FOR may contain
3453 non-gimple expressions when the main index variable has had
3454 its address taken. This does not affect the loop itself
3455 because the header of an OMP_FOR is merely used to determine
3456 how to setup the parallel iteration. */
3460 if (!is_gimple_stmt (stmt))
3462 error ("is not a valid GIMPLE statement");
3466 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3469 debug_generic_stmt (addr);
3473 /* If the statement is marked as part of an EH region, then it is
3474 expected that the statement could throw. Verify that when we
3475 have optimizations that simplify statements such that we prove
3476 that they cannot throw, that we update other data structures
3478 if (lookup_stmt_eh_region (stmt) >= 0)
3480 if (!tree_could_throw_p (stmt))
3482 error ("statement marked for throw, but doesn%'t");
3485 if (!last_in_block && tree_can_throw_internal (stmt))
3487 error ("statement marked for throw in middle of block");
3495 debug_generic_stmt (stmt);
3500 /* Return true when the T can be shared. */
3503 tree_node_can_be_shared (tree t)
3505 if (IS_TYPE_OR_DECL_P (t)
3506 || is_gimple_min_invariant (t)
3507 || TREE_CODE (t) == SSA_NAME
3508 || t == error_mark_node
3509 || TREE_CODE (t) == IDENTIFIER_NODE)
3512 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3515 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3516 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3517 || TREE_CODE (t) == COMPONENT_REF
3518 || TREE_CODE (t) == REALPART_EXPR
3519 || TREE_CODE (t) == IMAGPART_EXPR)
3520 t = TREE_OPERAND (t, 0);
3529 /* Called via walk_trees. Verify tree sharing. */
3532 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3534 htab_t htab = (htab_t) data;
3537 if (tree_node_can_be_shared (*tp))
3539 *walk_subtrees = false;
3543 slot = htab_find_slot (htab, *tp, INSERT);
3545 return (tree) *slot;
3552 /* Helper function for verify_gimple_tuples. */
3555 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3556 void *data ATTRIBUTE_UNUSED)
3558 switch (TREE_CODE (*tp))
3561 error ("unexpected non-tuple");
3571 /* Verify that there are no trees that should have been converted to
3572 gimple tuples. Return true if T contains a node that should have
3573 been converted to a gimple tuple, but hasn't. */
3576 verify_gimple_tuples (tree t)
3578 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3581 /* Verify the GIMPLE statement chain. */
3587 block_stmt_iterator bsi;
3592 timevar_push (TV_TREE_STMT_VERIFY);
3593 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3600 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3602 int phi_num_args = PHI_NUM_ARGS (phi);
3604 if (bb_for_stmt (phi) != bb)
3606 error ("bb_for_stmt (phi) is set to a wrong basic block");
3610 for (i = 0; i < phi_num_args; i++)
3612 tree t = PHI_ARG_DEF (phi, i);
3615 /* Addressable variables do have SSA_NAMEs but they
3616 are not considered gimple values. */
3617 if (TREE_CODE (t) != SSA_NAME
3618 && TREE_CODE (t) != FUNCTION_DECL
3619 && !is_gimple_val (t))
3621 error ("PHI def is not a GIMPLE value");
3622 debug_generic_stmt (phi);
3623 debug_generic_stmt (t);
3627 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3630 debug_generic_stmt (addr);
3634 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3637 error ("incorrect sharing of tree nodes");
3638 debug_generic_stmt (phi);
3639 debug_generic_stmt (addr);
3645 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3647 tree stmt = bsi_stmt (bsi);
3649 err |= verify_gimple_tuples (stmt);
3651 if (bb_for_stmt (stmt) != bb)
3653 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3658 err |= verify_stmt (stmt, bsi_end_p (bsi));
3659 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3662 error ("incorrect sharing of tree nodes");
3663 debug_generic_stmt (stmt);
3664 debug_generic_stmt (addr);
3671 internal_error ("verify_stmts failed");
3674 timevar_pop (TV_TREE_STMT_VERIFY);
3678 /* Verifies that the flow information is OK. */
3681 tree_verify_flow_info (void)
3685 block_stmt_iterator bsi;
3690 if (ENTRY_BLOCK_PTR->stmt_list)
3692 error ("ENTRY_BLOCK has a statement list associated with it");
3696 if (EXIT_BLOCK_PTR->stmt_list)
3698 error ("EXIT_BLOCK has a statement list associated with it");
3702 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3703 if (e->flags & EDGE_FALLTHRU)
3705 error ("fallthru to exit from bb %d", e->src->index);
3711 bool found_ctrl_stmt = false;
3715 /* Skip labels on the start of basic block. */
3716 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3718 tree prev_stmt = stmt;
3720 stmt = bsi_stmt (bsi);
3722 if (TREE_CODE (stmt) != LABEL_EXPR)
3725 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3727 error ("nonlocal label ");
3728 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3729 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3734 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3737 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3738 fprintf (stderr, " to block does not match in bb %d",
3743 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3744 != current_function_decl)
3747 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3748 fprintf (stderr, " has incorrect context in bb %d",
3754 /* Verify that body of basic block BB is free of control flow. */
3755 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3757 tree stmt = bsi_stmt (bsi);
3759 if (found_ctrl_stmt)
3761 error ("control flow in the middle of basic block %d",
3766 if (stmt_ends_bb_p (stmt))
3767 found_ctrl_stmt = true;
3769 if (TREE_CODE (stmt) == LABEL_EXPR)
3772 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3773 fprintf (stderr, " in the middle of basic block %d", bb->index);
3778 bsi = bsi_last (bb);
3779 if (bsi_end_p (bsi))
3782 stmt = bsi_stmt (bsi);
3784 err |= verify_eh_edges (stmt);
3786 if (is_ctrl_stmt (stmt))
3788 FOR_EACH_EDGE (e, ei, bb->succs)
3789 if (e->flags & EDGE_FALLTHRU)
3791 error ("fallthru edge after a control statement in bb %d",
3797 if (TREE_CODE (stmt) != COND_EXPR)
3799 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3800 after anything else but if statement. */
3801 FOR_EACH_EDGE (e, ei, bb->succs)
3802 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3804 error ("true/false edge after a non-COND_EXPR in bb %d",
3810 switch (TREE_CODE (stmt))
3816 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3817 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3819 error ("structured COND_EXPR at the end of bb %d", bb->index);
3823 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3825 if (!true_edge || !false_edge
3826 || !(true_edge->flags & EDGE_TRUE_VALUE)
3827 || !(false_edge->flags & EDGE_FALSE_VALUE)
3828 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3829 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3830 || EDGE_COUNT (bb->succs) >= 3)
3832 error ("wrong outgoing edge flags at end of bb %d",
3837 if (!has_label_p (true_edge->dest,
3838 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3840 error ("%<then%> label does not match edge at end of bb %d",
3845 if (!has_label_p (false_edge->dest,
3846 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3848 error ("%<else%> label does not match edge at end of bb %d",
3856 if (simple_goto_p (stmt))
3858 error ("explicit goto at end of bb %d", bb->index);
3863 /* FIXME. We should double check that the labels in the
3864 destination blocks have their address taken. */
3865 FOR_EACH_EDGE (e, ei, bb->succs)
3866 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3867 | EDGE_FALSE_VALUE))
3868 || !(e->flags & EDGE_ABNORMAL))
3870 error ("wrong outgoing edge flags at end of bb %d",
3878 if (!single_succ_p (bb)
3879 || (single_succ_edge (bb)->flags
3880 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3881 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3883 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3886 if (single_succ (bb) != EXIT_BLOCK_PTR)
3888 error ("return edge does not point to exit in bb %d",
3901 vec = SWITCH_LABELS (stmt);
3902 n = TREE_VEC_LENGTH (vec);
3904 /* Mark all the destination basic blocks. */
3905 for (i = 0; i < n; ++i)
3907 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3908 basic_block label_bb = label_to_block (lab);
3910 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3911 label_bb->aux = (void *)1;
3914 /* Verify that the case labels are sorted. */
3915 prev = TREE_VEC_ELT (vec, 0);
3916 for (i = 1; i < n - 1; ++i)
3918 tree c = TREE_VEC_ELT (vec, i);
3921 error ("found default case not at end of case vector");
3925 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3927 error ("case labels not sorted: ");
3928 print_generic_expr (stderr, prev, 0);
3929 fprintf (stderr," is greater than ");
3930 print_generic_expr (stderr, c, 0);
3931 fprintf (stderr," but comes before it.\n");
3936 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3938 error ("no default case found at end of case vector");
3942 FOR_EACH_EDGE (e, ei, bb->succs)
3946 error ("extra outgoing edge %d->%d",
3947 bb->index, e->dest->index);
3950 e->dest->aux = (void *)2;
3951 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3952 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3954 error ("wrong outgoing edge flags at end of bb %d",
3960 /* Check that we have all of them. */
3961 for (i = 0; i < n; ++i)
3963 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3964 basic_block label_bb = label_to_block (lab);
3966 if (label_bb->aux != (void *)2)
3968 error ("missing edge %i->%i",
3969 bb->index, label_bb->index);
3974 FOR_EACH_EDGE (e, ei, bb->succs)
3975 e->dest->aux = (void *)0;
3982 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3983 verify_dominators (CDI_DOMINATORS);
3989 /* Updates phi nodes after creating a forwarder block joined
3990 by edge FALLTHRU. */
3993 tree_make_forwarder_block (edge fallthru)
3997 basic_block dummy, bb;
3998 tree phi, new_phi, var;
4000 dummy = fallthru->src;
4001 bb = fallthru->dest;
4003 if (single_pred_p (bb))
4006 /* If we redirected a branch we must create new PHI nodes at the
4008 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
4010 var = PHI_RESULT (phi);
4011 new_phi = create_phi_node (var, bb);
4012 SSA_NAME_DEF_STMT (var) = new_phi;
4013 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
4014 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
4017 /* Ensure that the PHI node chain is in the same order. */
4018 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
4020 /* Add the arguments we have stored on edges. */
4021 FOR_EACH_EDGE (e, ei, bb->preds)
4026 flush_pending_stmts (e);
4031 /* Return a non-special label in the head of basic block BLOCK.
4032 Create one if it doesn't exist. */
4035 tree_block_label (basic_block bb)
4037 block_stmt_iterator i, s = bsi_start (bb);
4041 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4043 stmt = bsi_stmt (i);
4044 if (TREE_CODE (stmt) != LABEL_EXPR)
4046 label = LABEL_EXPR_LABEL (stmt);
4047 if (!DECL_NONLOCAL (label))
4050 bsi_move_before (&i, &s);
4055 label = create_artificial_label ();
4056 stmt = build1 (LABEL_EXPR, void_type_node, label);
4057 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4062 /* Attempt to perform edge redirection by replacing a possibly complex
4063 jump instruction by a goto or by removing the jump completely.
4064 This can apply only if all edges now point to the same block. The
4065 parameters and return values are equivalent to
4066 redirect_edge_and_branch. */
4069 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4071 basic_block src = e->src;
4072 block_stmt_iterator b;
4075 /* We can replace or remove a complex jump only when we have exactly
4077 if (EDGE_COUNT (src->succs) != 2
4078 /* Verify that all targets will be TARGET. Specifically, the
4079 edge that is not E must also go to TARGET. */
4080 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4086 stmt = bsi_stmt (b);
4088 if (TREE_CODE (stmt) == COND_EXPR
4089 || TREE_CODE (stmt) == SWITCH_EXPR)
4091 bsi_remove (&b, true);
4092 e = ssa_redirect_edge (e, target);
4093 e->flags = EDGE_FALLTHRU;
4101 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4102 edge representing the redirected branch. */
4105 tree_redirect_edge_and_branch (edge e, basic_block dest)
4107 basic_block bb = e->src;
4108 block_stmt_iterator bsi;
4112 if (e->flags & EDGE_ABNORMAL)
4115 if (e->src != ENTRY_BLOCK_PTR
4116 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4119 if (e->dest == dest)
4122 label = tree_block_label (dest);
4124 bsi = bsi_last (bb);
4125 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4127 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4130 stmt = (e->flags & EDGE_TRUE_VALUE
4131 ? COND_EXPR_THEN (stmt)
4132 : COND_EXPR_ELSE (stmt));
4133 GOTO_DESTINATION (stmt) = label;
4137 /* No non-abnormal edges should lead from a non-simple goto, and
4138 simple ones should be represented implicitly. */
4143 tree cases = get_cases_for_edge (e, stmt);
4145 /* If we have a list of cases associated with E, then use it
4146 as it's a lot faster than walking the entire case vector. */
4149 edge e2 = find_edge (e->src, dest);
4156 CASE_LABEL (cases) = label;
4157 cases = TREE_CHAIN (cases);
4160 /* If there was already an edge in the CFG, then we need
4161 to move all the cases associated with E to E2. */
4164 tree cases2 = get_cases_for_edge (e2, stmt);
4166 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4167 TREE_CHAIN (cases2) = first;
4172 tree vec = SWITCH_LABELS (stmt);
4173 size_t i, n = TREE_VEC_LENGTH (vec);
4175 for (i = 0; i < n; i++)
4177 tree elt = TREE_VEC_ELT (vec, i);
4179 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4180 CASE_LABEL (elt) = label;
4188 bsi_remove (&bsi, true);
4189 e->flags |= EDGE_FALLTHRU;
4193 /* Otherwise it must be a fallthru edge, and we don't need to
4194 do anything besides redirecting it. */
4195 gcc_assert (e->flags & EDGE_FALLTHRU);
4199 /* Update/insert PHI nodes as necessary. */
4201 /* Now update the edges in the CFG. */
4202 e = ssa_redirect_edge (e, dest);
4208 /* Simple wrapper, as we can always redirect fallthru edges. */
4211 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4213 e = tree_redirect_edge_and_branch (e, dest);
4220 /* Splits basic block BB after statement STMT (but at least after the
4221 labels). If STMT is NULL, BB is split just after the labels. */
4224 tree_split_block (basic_block bb, void *stmt)
4226 block_stmt_iterator bsi;
4227 tree_stmt_iterator tsi_tgt;
4233 new_bb = create_empty_bb (bb);
4235 /* Redirect the outgoing edges. */
4236 new_bb->succs = bb->succs;
4238 FOR_EACH_EDGE (e, ei, new_bb->succs)
4241 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4244 /* Move everything from BSI to the new basic block. */
4245 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4247 act = bsi_stmt (bsi);
4248 if (TREE_CODE (act) == LABEL_EXPR)
4261 if (bsi_end_p (bsi))
4264 /* Split the statement list - avoid re-creating new containers as this
4265 brings ugly quadratic memory consumption in the inliner.
4266 (We are still quadratic since we need to update stmt BB pointers,
4268 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4269 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4270 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4271 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4277 /* Moves basic block BB after block AFTER. */
4280 tree_move_block_after (basic_block bb, basic_block after)
4282 if (bb->prev_bb == after)
4286 link_block (bb, after);
4292 /* Return true if basic_block can be duplicated. */
4295 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4301 /* Create a duplicate of the basic block BB. NOTE: This does not
4302 preserve SSA form. */
4305 tree_duplicate_bb (basic_block bb)
4308 block_stmt_iterator bsi, bsi_tgt;
4311 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4313 /* Copy the PHI nodes. We ignore PHI node arguments here because
4314 the incoming edges have not been setup yet. */
4315 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4317 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4318 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4321 /* Keep the chain of PHI nodes in the same order so that they can be
4322 updated by ssa_redirect_edge. */
4323 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4325 bsi_tgt = bsi_start (new_bb);
4326 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4328 def_operand_p def_p;
4329 ssa_op_iter op_iter;
4333 stmt = bsi_stmt (bsi);
4334 if (TREE_CODE (stmt) == LABEL_EXPR)
4337 /* Create a new copy of STMT and duplicate STMT's virtual
4339 copy = unshare_expr (stmt);
4340 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4341 copy_virtual_operands (copy, stmt);
4342 region = lookup_stmt_eh_region (stmt);
4344 add_stmt_to_eh_region (copy, region);
4346 /* Create new names for all the definitions created by COPY and
4347 add replacement mappings for each new name. */
4348 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4349 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4356 /* Basic block BB_COPY was created by code duplication. Add phi node
4357 arguments for edges going out of BB_COPY. The blocks that were
4358 duplicated have BB_DUPLICATED set. */
4361 add_phi_args_after_copy_bb (basic_block bb_copy)
4363 basic_block bb, dest;
4366 tree phi, phi_copy, phi_next, def;
4368 bb = get_bb_original (bb_copy);
4370 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4372 if (!phi_nodes (e_copy->dest))
4375 if (e_copy->dest->flags & BB_DUPLICATED)
4376 dest = get_bb_original (e_copy->dest);
4378 dest = e_copy->dest;
4380 e = find_edge (bb, dest);
4383 /* During loop unrolling the target of the latch edge is copied.
4384 In this case we are not looking for edge to dest, but to
4385 duplicated block whose original was dest. */
4386 FOR_EACH_EDGE (e, ei, bb->succs)
4387 if ((e->dest->flags & BB_DUPLICATED)
4388 && get_bb_original (e->dest) == dest)
4391 gcc_assert (e != NULL);
4394 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4396 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4398 phi_next = PHI_CHAIN (phi);
4399 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4400 add_phi_arg (phi_copy, def, e_copy);
4405 /* Blocks in REGION_COPY array of length N_REGION were created by
4406 duplication of basic blocks. Add phi node arguments for edges
4407 going from these blocks. */
4410 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4414 for (i = 0; i < n_region; i++)
4415 region_copy[i]->flags |= BB_DUPLICATED;
4417 for (i = 0; i < n_region; i++)
4418 add_phi_args_after_copy_bb (region_copy[i]);
4420 for (i = 0; i < n_region; i++)
4421 region_copy[i]->flags &= ~BB_DUPLICATED;
4424 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4425 important exit edge EXIT. By important we mean that no SSA name defined
4426 inside region is live over the other exit edges of the region. All entry
4427 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4428 to the duplicate of the region. SSA form, dominance and loop information
4429 is updated. The new basic blocks are stored to REGION_COPY in the same
4430 order as they had in REGION, provided that REGION_COPY is not NULL.
4431 The function returns false if it is unable to copy the region,
4435 tree_duplicate_sese_region (edge entry, edge exit,
4436 basic_block *region, unsigned n_region,
4437 basic_block *region_copy)
4440 bool free_region_copy = false, copying_header = false;
4441 struct loop *loop = entry->dest->loop_father;
4445 int total_freq = 0, entry_freq = 0;
4446 gcov_type total_count = 0, entry_count = 0;
4448 if (!can_copy_bbs_p (region, n_region))
4451 /* Some sanity checking. Note that we do not check for all possible
4452 missuses of the functions. I.e. if you ask to copy something weird,
4453 it will work, but the state of structures probably will not be
4455 for (i = 0; i < n_region; i++)
4457 /* We do not handle subloops, i.e. all the blocks must belong to the
4459 if (region[i]->loop_father != loop)
4462 if (region[i] != entry->dest
4463 && region[i] == loop->header)
4469 /* In case the function is used for loop header copying (which is the primary
4470 use), ensure that EXIT and its copy will be new latch and entry edges. */
4471 if (loop->header == entry->dest)
4473 copying_header = true;
4474 loop->copy = loop->outer;
4476 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4479 for (i = 0; i < n_region; i++)
4480 if (region[i] != exit->src
4481 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4487 region_copy = XNEWVEC (basic_block, n_region);
4488 free_region_copy = true;
4491 gcc_assert (!need_ssa_update_p ());
4493 /* Record blocks outside the region that are dominated by something
4495 doms = XNEWVEC (basic_block, n_basic_blocks);
4496 initialize_original_copy_tables ();
4498 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4500 if (entry->dest->count)
4502 total_count = entry->dest->count;
4503 entry_count = entry->count;
4504 /* Fix up corner cases, to avoid division by zero or creation of negative
4506 if (entry_count > total_count)
4507 entry_count = total_count;
4511 total_freq = entry->dest->frequency;
4512 entry_freq = EDGE_FREQUENCY (entry);
4513 /* Fix up corner cases, to avoid division by zero or creation of negative
4515 if (total_freq == 0)
4517 else if (entry_freq > total_freq)
4518 entry_freq = total_freq;
4521 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4522 split_edge_bb_loc (entry));
4525 scale_bbs_frequencies_gcov_type (region, n_region,
4526 total_count - entry_count,
4528 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4533 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4535 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4540 loop->header = exit->dest;
4541 loop->latch = exit->src;
4544 /* Redirect the entry and add the phi node arguments. */
4545 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4546 gcc_assert (redirected != NULL);
4547 flush_pending_stmts (entry);
4549 /* Concerning updating of dominators: We must recount dominators
4550 for entry block and its copy. Anything that is outside of the
4551 region, but was dominated by something inside needs recounting as
4553 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4554 doms[n_doms++] = get_bb_original (entry->dest);
4555 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4558 /* Add the other PHI node arguments. */
4559 add_phi_args_after_copy (region_copy, n_region);
4561 /* Update the SSA web. */
4562 update_ssa (TODO_update_ssa);
4564 if (free_region_copy)
4567 free_original_copy_tables ();
4572 DEF_VEC_P(basic_block);
4573 DEF_VEC_ALLOC_P(basic_block,heap);
4576 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4577 adding blocks when the dominator traversal reaches EXIT. This
4578 function silently assumes that ENTRY strictly dominates EXIT. */
4581 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4582 VEC(basic_block,heap) **bbs_p)
4586 for (son = first_dom_son (CDI_DOMINATORS, entry);
4588 son = next_dom_son (CDI_DOMINATORS, son))
4590 VEC_safe_push (basic_block, heap, *bbs_p, son);
4592 gather_blocks_in_sese_region (son, exit, bbs_p);
4602 bitmap vars_to_remove;
4603 htab_t new_label_map;
4607 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4608 contained in *TP and change the DECL_CONTEXT of every local
4609 variable referenced in *TP. */
4612 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4614 struct move_stmt_d *p = (struct move_stmt_d *) data;
4618 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4619 TREE_BLOCK (t) = p->block;
4621 if (OMP_DIRECTIVE_P (t)
4622 && TREE_CODE (t) != OMP_RETURN
4623 && TREE_CODE (t) != OMP_CONTINUE)
4625 /* Do not remap variables inside OMP directives. Variables
4626 referenced in clauses and directive header belong to the
4627 parent function and should not be moved into the child
4629 bool save_remap_decls_p = p->remap_decls_p;
4630 p->remap_decls_p = false;
4633 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4635 p->remap_decls_p = save_remap_decls_p;
4637 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4639 if (TREE_CODE (t) == LABEL_DECL)
4641 if (p->new_label_map)
4643 struct tree_map in, *out;
4645 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4650 DECL_CONTEXT (t) = p->to_context;
4652 else if (p->remap_decls_p)
4654 DECL_CONTEXT (t) = p->to_context;
4656 if (TREE_CODE (t) == VAR_DECL)
4658 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4659 f->unexpanded_var_list
4660 = tree_cons (0, t, f->unexpanded_var_list);
4662 /* Mark T to be removed from the original function,
4663 otherwise it will be given a DECL_RTL when the
4664 original function is expanded. */
4665 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4669 else if (TYPE_P (t))
4676 /* Move basic block BB from function CFUN to function DEST_FN. The
4677 block is moved out of the original linked list and placed after
4678 block AFTER in the new list. Also, the block is removed from the
4679 original array of blocks and placed in DEST_FN's array of blocks.
4680 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4681 updated to reflect the moved edges.
4683 On exit, local variables that need to be removed from
4684 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4687 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4688 basic_block after, bool update_edge_count_p,
4689 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4691 struct control_flow_graph *cfg;
4694 block_stmt_iterator si;
4695 struct move_stmt_d d;
4696 unsigned old_len, new_len;
4699 /* Link BB to the new linked list. */
4700 move_block_after (bb, after);
4702 /* Update the edge count in the corresponding flowgraphs. */
4703 if (update_edge_count_p)
4704 FOR_EACH_EDGE (e, ei, bb->succs)
4706 cfun->cfg->x_n_edges--;
4707 dest_cfun->cfg->x_n_edges++;
4710 /* Remove BB from the original basic block array. */
4711 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4712 cfun->cfg->x_n_basic_blocks--;
4714 /* Grow DEST_CFUN's basic block array if needed. */
4715 cfg = dest_cfun->cfg;
4716 cfg->x_n_basic_blocks++;
4717 if (bb->index > cfg->x_last_basic_block)
4718 cfg->x_last_basic_block = bb->index;
4720 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4721 if ((unsigned) cfg->x_last_basic_block >= old_len)
4723 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4724 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4725 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4726 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4729 VEC_replace (basic_block, cfg->x_basic_block_info,
4730 cfg->x_last_basic_block, bb);
4732 /* The statements in BB need to be associated with a new TREE_BLOCK.
4733 Labels need to be associated with a new label-to-block map. */
4734 memset (&d, 0, sizeof (d));
4735 d.vars_to_remove = vars_to_remove;
4737 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4739 tree stmt = bsi_stmt (si);
4742 d.from_context = cfun->decl;
4743 d.to_context = dest_cfun->decl;
4744 d.remap_decls_p = true;
4745 d.new_label_map = new_label_map;
4746 if (TREE_BLOCK (stmt))
4747 d.block = DECL_INITIAL (dest_cfun->decl);
4749 walk_tree (&stmt, move_stmt_r, &d, NULL);
4751 if (TREE_CODE (stmt) == LABEL_EXPR)
4753 tree label = LABEL_EXPR_LABEL (stmt);
4754 int uid = LABEL_DECL_UID (label);
4756 gcc_assert (uid > -1);
4758 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4759 if (old_len <= (unsigned) uid)
4761 new_len = 3 * uid / 2;
4762 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4764 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4765 memset (&addr[old_len], 0,
4766 sizeof (basic_block) * (new_len - old_len));
4769 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4770 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4772 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4774 if (uid >= dest_cfun->last_label_uid)
4775 dest_cfun->last_label_uid = uid + 1;
4777 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4778 TREE_OPERAND (stmt, 0) =
4779 build_int_cst (NULL_TREE,
4780 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4783 region = lookup_stmt_eh_region (stmt);
4786 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4787 remove_stmt_from_eh_region (stmt);
4792 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4793 the outermost EH region. Use REGION as the incoming base EH region. */
4796 find_outermost_region_in_block (struct function *src_cfun,
4797 basic_block bb, int region)
4799 block_stmt_iterator si;
4801 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4803 tree stmt = bsi_stmt (si);
4806 if (TREE_CODE (stmt) == RESX_EXPR)
4807 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4809 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4810 if (stmt_region > 0)
4813 region = stmt_region;
4814 else if (stmt_region != region)
4816 region = eh_region_outermost (src_cfun, stmt_region, region);
4817 gcc_assert (region != -1);
4826 new_label_mapper (tree decl, void *data)
4828 htab_t hash = (htab_t) data;
4832 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4834 m = xmalloc (sizeof (struct tree_map));
4835 m->hash = DECL_UID (decl);
4837 m->to = create_artificial_label ();
4838 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4840 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4841 gcc_assert (*slot == NULL);
4848 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4849 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4850 single basic block in the original CFG and the new basic block is
4851 returned. DEST_CFUN must not have a CFG yet.
4853 Note that the region need not be a pure SESE region. Blocks inside
4854 the region may contain calls to abort/exit. The only restriction
4855 is that ENTRY_BB should be the only entry point and it must
4858 All local variables referenced in the region are assumed to be in
4859 the corresponding BLOCK_VARS and unexpanded variable lists
4860 associated with DEST_CFUN. */
4863 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4864 basic_block exit_bb)
4866 VEC(basic_block,heap) *bbs;
4867 basic_block after, bb, *entry_pred, *exit_succ;
4868 struct function *saved_cfun;
4869 int *entry_flag, *exit_flag, eh_offset;
4870 unsigned i, num_entry_edges, num_exit_edges;
4873 bitmap vars_to_remove;
4874 htab_t new_label_map;
4878 /* Collect all the blocks in the region. Manually add ENTRY_BB
4879 because it won't be added by dfs_enumerate_from. */
4880 calculate_dominance_info (CDI_DOMINATORS);
4882 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4884 gcc_assert (entry_bb != exit_bb
4886 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4889 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4890 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4892 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4893 the predecessor edges to ENTRY_BB and the successor edges to
4894 EXIT_BB so that we can re-attach them to the new basic block that
4895 will replace the region. */
4896 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4897 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4898 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4900 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4902 entry_flag[i] = e->flags;
4903 entry_pred[i++] = e->src;
4909 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4910 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4911 sizeof (basic_block));
4912 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4914 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4916 exit_flag[i] = e->flags;
4917 exit_succ[i++] = e->dest;
4928 /* Switch context to the child function to initialize DEST_FN's CFG. */
4929 gcc_assert (dest_cfun->cfg == NULL);
4932 init_empty_tree_cfg ();
4934 /* Initialize EH information for the new function. */
4936 new_label_map = NULL;
4941 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4942 region = find_outermost_region_in_block (saved_cfun, bb, region);
4944 init_eh_for_function ();
4947 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4948 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4949 new_label_map, region, 0);
4955 /* Move blocks from BBS into DEST_CFUN. */
4956 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4957 after = dest_cfun->cfg->x_entry_block_ptr;
4958 vars_to_remove = BITMAP_ALLOC (NULL);
4959 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4961 /* No need to update edge counts on the last block. It has
4962 already been updated earlier when we detached the region from
4963 the original CFG. */
4964 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4965 new_label_map, eh_offset);
4970 htab_delete (new_label_map);
4972 /* Remove the variables marked in VARS_TO_REMOVE from
4973 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4974 DECL_RTL in the context of CFUN. */
4975 if (!bitmap_empty_p (vars_to_remove))
4979 for (p = &cfun->unexpanded_var_list; *p; )
4981 tree var = TREE_VALUE (*p);
4982 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4984 *p = TREE_CHAIN (*p);
4988 p = &TREE_CHAIN (*p);
4992 BITMAP_FREE (vars_to_remove);
4994 /* Rewire the entry and exit blocks. The successor to the entry
4995 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4996 the child function. Similarly, the predecessor of DEST_FN's
4997 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4998 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4999 various CFG manipulation function get to the right CFG.
5001 FIXME, this is silly. The CFG ought to become a parameter to
5004 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
5006 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
5009 /* Back in the original function, the SESE region has disappeared,
5010 create a new basic block in its place. */
5011 bb = create_empty_bb (entry_pred[0]);
5012 for (i = 0; i < num_entry_edges; i++)
5013 make_edge (entry_pred[i], bb, entry_flag[i]);
5015 for (i = 0; i < num_exit_edges; i++)
5016 make_edge (bb, exit_succ[i], exit_flag[i]);
5025 free_dominance_info (CDI_DOMINATORS);
5026 free_dominance_info (CDI_POST_DOMINATORS);
5027 VEC_free (basic_block, heap, bbs);
5033 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5036 dump_function_to_file (tree fn, FILE *file, int flags)
5038 tree arg, vars, var;
5039 bool ignore_topmost_bind = false, any_var = false;
5042 struct function *saved_cfun;
5044 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5046 arg = DECL_ARGUMENTS (fn);
5049 print_generic_expr (file, arg, dump_flags);
5050 if (TREE_CHAIN (arg))
5051 fprintf (file, ", ");
5052 arg = TREE_CHAIN (arg);
5054 fprintf (file, ")\n");
5056 if (flags & TDF_DETAILS)
5057 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5058 if (flags & TDF_RAW)
5060 dump_node (fn, TDF_SLIM | flags, file);
5064 /* Switch CFUN to point to FN. */
5066 cfun = DECL_STRUCT_FUNCTION (fn);
5068 /* When GIMPLE is lowered, the variables are no longer available in
5069 BIND_EXPRs, so display them separately. */
5070 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5072 ignore_topmost_bind = true;
5074 fprintf (file, "{\n");
5075 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5077 var = TREE_VALUE (vars);
5079 print_generic_decl (file, var, flags);
5080 fprintf (file, "\n");
5086 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5088 /* Make a CFG based dump. */
5089 check_bb_profile (ENTRY_BLOCK_PTR, file);
5090 if (!ignore_topmost_bind)
5091 fprintf (file, "{\n");
5093 if (any_var && n_basic_blocks)
5094 fprintf (file, "\n");
5097 dump_generic_bb (file, bb, 2, flags);
5099 fprintf (file, "}\n");
5100 check_bb_profile (EXIT_BLOCK_PTR, file);
5106 /* Make a tree based dump. */
5107 chain = DECL_SAVED_TREE (fn);
5109 if (chain && TREE_CODE (chain) == BIND_EXPR)
5111 if (ignore_topmost_bind)
5113 chain = BIND_EXPR_BODY (chain);
5121 if (!ignore_topmost_bind)
5122 fprintf (file, "{\n");
5127 fprintf (file, "\n");
5129 print_generic_stmt_indented (file, chain, flags, indent);
5130 if (ignore_topmost_bind)
5131 fprintf (file, "}\n");
5134 fprintf (file, "\n\n");
5141 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5144 debug_function (tree fn, int flags)
5146 dump_function_to_file (fn, stderr, flags);
5150 /* Pretty print of the loops intermediate representation. */
5151 static void print_loop (FILE *, struct loop *, int);
5152 static void print_pred_bbs (FILE *, basic_block bb);
5153 static void print_succ_bbs (FILE *, basic_block bb);
5156 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5159 print_pred_bbs (FILE *file, basic_block bb)
5164 FOR_EACH_EDGE (e, ei, bb->preds)
5165 fprintf (file, "bb_%d ", e->src->index);
5169 /* Print on FILE the indexes for the successors of basic_block BB. */
5172 print_succ_bbs (FILE *file, basic_block bb)
5177 FOR_EACH_EDGE (e, ei, bb->succs)
5178 fprintf (file, "bb_%d ", e->dest->index);
5182 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5185 print_loop (FILE *file, struct loop *loop, int indent)
5193 s_indent = (char *) alloca ((size_t) indent + 1);
5194 memset ((void *) s_indent, ' ', (size_t) indent);
5195 s_indent[indent] = '\0';
5197 /* Print the loop's header. */
5198 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5200 /* Print the loop's body. */
5201 fprintf (file, "%s{\n", s_indent);
5203 if (bb->loop_father == loop)
5205 /* Print the basic_block's header. */
5206 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5207 print_pred_bbs (file, bb);
5208 fprintf (file, "}, succs = {");
5209 print_succ_bbs (file, bb);
5210 fprintf (file, "})\n");
5212 /* Print the basic_block's body. */
5213 fprintf (file, "%s {\n", s_indent);
5214 tree_dump_bb (bb, file, indent + 4);
5215 fprintf (file, "%s }\n", s_indent);
5218 print_loop (file, loop->inner, indent + 2);
5219 fprintf (file, "%s}\n", s_indent);
5220 print_loop (file, loop->next, indent);
5224 /* Follow a CFG edge from the entry point of the program, and on entry
5225 of a loop, pretty print the loop structure on FILE. */
5228 print_loop_ir (FILE *file)
5232 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5233 if (bb && bb->loop_father)
5234 print_loop (file, bb->loop_father, 0);
5238 /* Debugging loops structure at tree level. */
5241 debug_loop_ir (void)
5243 print_loop_ir (stderr);
5247 /* Return true if BB ends with a call, possibly followed by some
5248 instructions that must stay with the call. Return false,
5252 tree_block_ends_with_call_p (basic_block bb)
5254 block_stmt_iterator bsi = bsi_last (bb);
5255 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5259 /* Return true if BB ends with a conditional branch. Return false,
5263 tree_block_ends_with_condjump_p (basic_block bb)
5265 tree stmt = last_stmt (bb);
5266 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5270 /* Return true if we need to add fake edge to exit at statement T.
5271 Helper function for tree_flow_call_edges_add. */
5274 need_fake_edge_p (tree t)
5278 /* NORETURN and LONGJMP calls already have an edge to exit.
5279 CONST and PURE calls do not need one.
5280 We don't currently check for CONST and PURE here, although
5281 it would be a good idea, because those attributes are
5282 figured out from the RTL in mark_constant_function, and
5283 the counter incrementation code from -fprofile-arcs
5284 leads to different results from -fbranch-probabilities. */
5285 call = get_call_expr_in (t);
5287 && !(call_expr_flags (call) & ECF_NORETURN))
5290 if (TREE_CODE (t) == ASM_EXPR
5291 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5298 /* Add fake edges to the function exit for any non constant and non
5299 noreturn calls, volatile inline assembly in the bitmap of blocks
5300 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5301 the number of blocks that were split.
5303 The goal is to expose cases in which entering a basic block does
5304 not imply that all subsequent instructions must be executed. */
5307 tree_flow_call_edges_add (sbitmap blocks)
5310 int blocks_split = 0;
5311 int last_bb = last_basic_block;
5312 bool check_last_block = false;
5314 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5318 check_last_block = true;
5320 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5322 /* In the last basic block, before epilogue generation, there will be
5323 a fallthru edge to EXIT. Special care is required if the last insn
5324 of the last basic block is a call because make_edge folds duplicate
5325 edges, which would result in the fallthru edge also being marked
5326 fake, which would result in the fallthru edge being removed by
5327 remove_fake_edges, which would result in an invalid CFG.
5329 Moreover, we can't elide the outgoing fake edge, since the block
5330 profiler needs to take this into account in order to solve the minimal
5331 spanning tree in the case that the call doesn't return.
5333 Handle this by adding a dummy instruction in a new last basic block. */
5334 if (check_last_block)
5336 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5337 block_stmt_iterator bsi = bsi_last (bb);
5339 if (!bsi_end_p (bsi))
5342 if (t && need_fake_edge_p (t))
5346 e = find_edge (bb, EXIT_BLOCK_PTR);
5349 bsi_insert_on_edge (e, build_empty_stmt ());
5350 bsi_commit_edge_inserts ();
5355 /* Now add fake edges to the function exit for any non constant
5356 calls since there is no way that we can determine if they will
5358 for (i = 0; i < last_bb; i++)
5360 basic_block bb = BASIC_BLOCK (i);
5361 block_stmt_iterator bsi;
5362 tree stmt, last_stmt;
5367 if (blocks && !TEST_BIT (blocks, i))
5370 bsi = bsi_last (bb);
5371 if (!bsi_end_p (bsi))
5373 last_stmt = bsi_stmt (bsi);
5376 stmt = bsi_stmt (bsi);
5377 if (need_fake_edge_p (stmt))
5380 /* The handling above of the final block before the
5381 epilogue should be enough to verify that there is
5382 no edge to the exit block in CFG already.
5383 Calling make_edge in such case would cause us to
5384 mark that edge as fake and remove it later. */
5385 #ifdef ENABLE_CHECKING
5386 if (stmt == last_stmt)
5388 e = find_edge (bb, EXIT_BLOCK_PTR);
5389 gcc_assert (e == NULL);
5393 /* Note that the following may create a new basic block
5394 and renumber the existing basic blocks. */
5395 if (stmt != last_stmt)
5397 e = split_block (bb, stmt);
5401 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5405 while (!bsi_end_p (bsi));
5410 verify_flow_info ();
5412 return blocks_split;
5415 /* Purge dead abnormal call edges from basic block BB. */
5418 tree_purge_dead_abnormal_call_edges (basic_block bb)
5420 bool changed = tree_purge_dead_eh_edges (bb);
5422 if (current_function_has_nonlocal_label)
5424 tree stmt = last_stmt (bb);
5428 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5429 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5431 if (e->flags & EDGE_ABNORMAL)
5440 /* See tree_purge_dead_eh_edges below. */
5442 free_dominance_info (CDI_DOMINATORS);
5448 /* Purge dead EH edges from basic block BB. */
5451 tree_purge_dead_eh_edges (basic_block bb)
5453 bool changed = false;
5456 tree stmt = last_stmt (bb);
5458 if (stmt && tree_can_throw_internal (stmt))
5461 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5463 if (e->flags & EDGE_EH)
5472 /* Removal of dead EH edges might change dominators of not
5473 just immediate successors. E.g. when bb1 is changed so that
5474 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5475 eh edges purged by this function in:
5487 idom(bb5) must be recomputed. For now just free the dominance
5490 free_dominance_info (CDI_DOMINATORS);
5496 tree_purge_all_dead_eh_edges (bitmap blocks)
5498 bool changed = false;
5502 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5504 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5510 /* This function is called whenever a new edge is created or
5514 tree_execute_on_growing_pred (edge e)
5516 basic_block bb = e->dest;
5519 reserve_phi_args_for_new_edge (bb);
5522 /* This function is called immediately before edge E is removed from
5523 the edge vector E->dest->preds. */
5526 tree_execute_on_shrinking_pred (edge e)
5528 if (phi_nodes (e->dest))
5529 remove_phi_args (e);
5532 /*---------------------------------------------------------------------------
5533 Helper functions for Loop versioning
5534 ---------------------------------------------------------------------------*/
5536 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5537 of 'first'. Both of them are dominated by 'new_head' basic block. When
5538 'new_head' was created by 'second's incoming edge it received phi arguments
5539 on the edge by split_edge(). Later, additional edge 'e' was created to
5540 connect 'new_head' and 'first'. Now this routine adds phi args on this
5541 additional edge 'e' that new_head to second edge received as part of edge
5546 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5547 basic_block new_head, edge e)
5550 edge e2 = find_edge (new_head, second);
5552 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5553 edge, we should always have an edge from NEW_HEAD to SECOND. */
5554 gcc_assert (e2 != NULL);
5556 /* Browse all 'second' basic block phi nodes and add phi args to
5557 edge 'e' for 'first' head. PHI args are always in correct order. */
5559 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5561 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5563 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5564 add_phi_arg (phi1, def, e);
5568 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5569 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5570 the destination of the ELSE part. */
5572 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5573 basic_block cond_bb, void *cond_e)
5575 block_stmt_iterator bsi;
5576 tree goto1 = NULL_TREE;
5577 tree goto2 = NULL_TREE;
5578 tree new_cond_expr = NULL_TREE;
5579 tree cond_expr = (tree) cond_e;
5582 /* Build new conditional expr */
5583 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5584 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5585 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5587 /* Add new cond in cond_bb. */
5588 bsi = bsi_start (cond_bb);
5589 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5590 /* Adjust edges appropriately to connect new head with first head
5591 as well as second head. */
5592 e0 = single_succ_edge (cond_bb);
5593 e0->flags &= ~EDGE_FALLTHRU;
5594 e0->flags |= EDGE_FALSE_VALUE;
5597 struct cfg_hooks tree_cfg_hooks = {
5599 tree_verify_flow_info,
5600 tree_dump_bb, /* dump_bb */
5601 create_bb, /* create_basic_block */
5602 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5603 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5604 remove_bb, /* delete_basic_block */
5605 tree_split_block, /* split_block */
5606 tree_move_block_after, /* move_block_after */
5607 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5608 tree_merge_blocks, /* merge_blocks */
5609 tree_predict_edge, /* predict_edge */
5610 tree_predicted_by_p, /* predicted_by_p */
5611 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5612 tree_duplicate_bb, /* duplicate_block */
5613 tree_split_edge, /* split_edge */
5614 tree_make_forwarder_block, /* make_forward_block */
5615 NULL, /* tidy_fallthru_edge */
5616 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5617 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5618 tree_flow_call_edges_add, /* flow_call_edges_add */
5619 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5620 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5621 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5622 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5623 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5624 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5625 flush_pending_stmts /* flush_pending_stmts */
5629 /* Split all critical edges. */
5632 split_critical_edges (void)
5638 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5639 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5640 mappings around the calls to split_edge. */
5641 start_recording_case_labels ();
5644 FOR_EACH_EDGE (e, ei, bb->succs)
5645 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5650 end_recording_case_labels ();
5654 struct tree_opt_pass pass_split_crit_edges =
5656 "crited", /* name */
5658 split_critical_edges, /* execute */
5661 0, /* static_pass_number */
5662 TV_TREE_SPLIT_EDGES, /* tv_id */
5663 PROP_cfg, /* properties required */
5664 PROP_no_crit_edges, /* properties_provided */
5665 0, /* properties_destroyed */
5666 0, /* todo_flags_start */
5667 TODO_dump_func, /* todo_flags_finish */
5672 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5673 a temporary, make sure and register it to be renamed if necessary,
5674 and finally return the temporary. Put the statements to compute
5675 EXP before the current statement in BSI. */
5678 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5680 tree t, new_stmt, orig_stmt;
5682 if (is_gimple_val (exp))
5685 t = make_rename_temp (type, NULL);
5686 new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, t, exp);
5688 orig_stmt = bsi_stmt (*bsi);
5689 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5690 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5692 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5693 if (gimple_in_ssa_p (cfun))
5694 mark_symbols_for_renaming (new_stmt);
5699 /* Build a ternary operation and gimplify it. Emit code before BSI.
5700 Return the gimple_val holding the result. */
5703 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5704 tree type, tree a, tree b, tree c)
5708 ret = fold_build3 (code, type, a, b, c);
5711 return gimplify_val (bsi, type, ret);
5714 /* Build a binary operation and gimplify it. Emit code before BSI.
5715 Return the gimple_val holding the result. */
5718 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5719 tree type, tree a, tree b)
5723 ret = fold_build2 (code, type, a, b);
5726 return gimplify_val (bsi, type, ret);
5729 /* Build a unary operation and gimplify it. Emit code before BSI.
5730 Return the gimple_val holding the result. */
5733 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5738 ret = fold_build1 (code, type, a);
5741 return gimplify_val (bsi, type, ret);
5746 /* Emit return warnings. */
5749 execute_warn_function_return (void)
5751 #ifdef USE_MAPPED_LOCATION
5752 source_location location;
5760 /* If we have a path to EXIT, then we do return. */
5761 if (TREE_THIS_VOLATILE (cfun->decl)
5762 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5764 #ifdef USE_MAPPED_LOCATION
5765 location = UNKNOWN_LOCATION;
5769 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5771 last = last_stmt (e->src);
5772 if (TREE_CODE (last) == RETURN_EXPR
5773 #ifdef USE_MAPPED_LOCATION
5774 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5776 && (locus = EXPR_LOCUS (last)) != NULL)
5780 #ifdef USE_MAPPED_LOCATION
5781 if (location == UNKNOWN_LOCATION)
5782 location = cfun->function_end_locus;
5783 warning (0, "%H%<noreturn%> function does return", &location);
5786 locus = &cfun->function_end_locus;
5787 warning (0, "%H%<noreturn%> function does return", locus);
5791 /* If we see "return;" in some basic block, then we do reach the end
5792 without returning a value. */
5793 else if (warn_return_type
5794 && !TREE_NO_WARNING (cfun->decl)
5795 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5796 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5798 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5800 tree last = last_stmt (e->src);
5801 if (TREE_CODE (last) == RETURN_EXPR
5802 && TREE_OPERAND (last, 0) == NULL
5803 && !TREE_NO_WARNING (last))
5805 #ifdef USE_MAPPED_LOCATION
5806 location = EXPR_LOCATION (last);
5807 if (location == UNKNOWN_LOCATION)
5808 location = cfun->function_end_locus;
5809 warning (0, "%Hcontrol reaches end of non-void function", &location);
5811 locus = EXPR_LOCUS (last);
5813 locus = &cfun->function_end_locus;
5814 warning (0, "%Hcontrol reaches end of non-void function", locus);
5816 TREE_NO_WARNING (cfun->decl) = 1;
5825 /* Given a basic block B which ends with a conditional and has
5826 precisely two successors, determine which of the edges is taken if
5827 the conditional is true and which is taken if the conditional is
5828 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5831 extract_true_false_edges_from_block (basic_block b,
5835 edge e = EDGE_SUCC (b, 0);
5837 if (e->flags & EDGE_TRUE_VALUE)
5840 *false_edge = EDGE_SUCC (b, 1);
5845 *true_edge = EDGE_SUCC (b, 1);
5849 struct tree_opt_pass pass_warn_function_return =
5853 execute_warn_function_return, /* execute */
5856 0, /* static_pass_number */
5858 PROP_cfg, /* properties_required */
5859 0, /* properties_provided */
5860 0, /* properties_destroyed */
5861 0, /* todo_flags_start */
5862 0, /* todo_flags_finish */
5866 /* Emit noreturn warnings. */
5869 execute_warn_function_noreturn (void)
5871 if (warn_missing_noreturn
5872 && !TREE_THIS_VOLATILE (cfun->decl)
5873 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5874 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5875 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5876 "for attribute %<noreturn%>",
5881 struct tree_opt_pass pass_warn_function_noreturn =
5885 execute_warn_function_noreturn, /* execute */
5888 0, /* static_pass_number */
5890 PROP_cfg, /* properties_required */
5891 0, /* properties_provided */
5892 0, /* properties_destroyed */
5893 0, /* todo_flags_start */
5894 0, /* todo_flags_finish */