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 (MODIFY_EXPR, ptr_type_node,
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)
438 fold_defer_overflow_warnings ();
439 cond = fold (COND_EXPR_COND (stmt));
440 zerop = integer_zerop (cond);
441 onep = integer_onep (cond);
442 fold_undefer_overflow_warnings (((zerop || onep)
443 && !TREE_NO_WARNING (stmt)),
445 WARN_STRICT_OVERFLOW_CONDITIONAL);
447 COND_EXPR_COND (stmt) = boolean_false_node;
449 COND_EXPR_COND (stmt) = boolean_true_node;
454 /* Join all the blocks in the flowgraph. */
460 struct omp_region *cur_region = NULL;
462 /* Create an edge from entry to the first block with executable
464 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
466 /* Traverse the basic block array placing edges. */
469 tree last = last_stmt (bb);
474 enum tree_code code = TREE_CODE (last);
478 make_goto_expr_edges (bb);
482 make_edge (bb, EXIT_BLOCK_PTR, 0);
486 make_cond_expr_edges (bb);
490 make_switch_expr_edges (bb);
494 make_eh_edges (last);
499 /* If this function receives a nonlocal goto, then we need to
500 make edges from this call site to all the nonlocal goto
502 if (tree_can_make_abnormal_goto (last))
503 make_abnormal_goto_edges (bb, true);
505 /* If this statement has reachable exception handlers, then
506 create abnormal edges to them. */
507 make_eh_edges (last);
509 /* Some calls are known not to return. */
510 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
514 if (is_ctrl_altering_stmt (last))
516 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
517 CALL_EXPR may have an abnormal edge. Search the RHS for
518 this case and create any required edges. */
519 if (tree_can_make_abnormal_goto (last))
520 make_abnormal_goto_edges (bb, true);
522 make_eh_edges (last);
534 cur_region = new_omp_region (bb, code, cur_region);
539 cur_region = new_omp_region (bb, code, cur_region);
544 /* In the case of an OMP_SECTION, the edge will go somewhere
545 other than the next block. This will be created later. */
546 cur_region->exit = bb;
547 fallthru = cur_region->type != OMP_SECTION;
548 cur_region = cur_region->outer;
552 cur_region->cont = bb;
553 switch (cur_region->type)
556 /* ??? Technically there should be a some sort of loopback
557 edge here, but it goes to a block that doesn't exist yet,
558 and without it, updating the ssa form would be a real
559 bear. Fortunately, we don't yet do ssa before expanding
564 /* Wire up the edges into and out of the nested sections. */
565 /* ??? Similarly wrt loopback. */
567 struct omp_region *i;
568 for (i = cur_region->inner; i ; i = i->next)
570 gcc_assert (i->type == OMP_SECTION);
571 make_edge (cur_region->entry, i->entry, 0);
572 make_edge (i->exit, bb, EDGE_FALLTHRU);
584 gcc_assert (!stmt_ends_bb_p (last));
592 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
598 /* Fold COND_EXPR_COND of each COND_EXPR. */
599 fold_cond_expr_cond ();
601 /* Clean up the graph and warn for unreachable code. */
606 /* Create the edges for a COND_EXPR starting at block BB.
607 At this point, both clauses must contain only simple gotos. */
610 make_cond_expr_edges (basic_block bb)
612 tree entry = last_stmt (bb);
613 basic_block then_bb, else_bb;
614 tree then_label, else_label;
618 gcc_assert (TREE_CODE (entry) == COND_EXPR);
620 /* Entry basic blocks for each component. */
621 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
622 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
623 then_bb = label_to_block (then_label);
624 else_bb = label_to_block (else_label);
626 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
627 #ifdef USE_MAPPED_LOCATION
628 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
630 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
632 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
635 #ifdef USE_MAPPED_LOCATION
636 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
638 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
643 /* Hashing routine for EDGE_TO_CASES. */
646 edge_to_cases_hash (const void *p)
648 edge e = ((struct edge_to_cases_elt *)p)->e;
650 /* Hash on the edge itself (which is a pointer). */
651 return htab_hash_pointer (e);
654 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
655 for equality is just a pointer comparison. */
658 edge_to_cases_eq (const void *p1, const void *p2)
660 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
661 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
666 /* Called for each element in the hash table (P) as we delete the
667 edge to cases hash table.
669 Clear all the TREE_CHAINs to prevent problems with copying of
670 SWITCH_EXPRs and structure sharing rules, then free the hash table
674 edge_to_cases_cleanup (void *p)
676 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
679 for (t = elt->case_labels; t; t = next)
681 next = TREE_CHAIN (t);
682 TREE_CHAIN (t) = NULL;
687 /* Start recording information mapping edges to case labels. */
690 start_recording_case_labels (void)
692 gcc_assert (edge_to_cases == NULL);
694 edge_to_cases = htab_create (37,
697 edge_to_cases_cleanup);
700 /* Return nonzero if we are recording information for case labels. */
703 recording_case_labels_p (void)
705 return (edge_to_cases != NULL);
708 /* Stop recording information mapping edges to case labels and
709 remove any information we have recorded. */
711 end_recording_case_labels (void)
713 htab_delete (edge_to_cases);
714 edge_to_cases = NULL;
717 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
720 record_switch_edge (edge e, tree case_label)
722 struct edge_to_cases_elt *elt;
725 /* Build a hash table element so we can see if E is already
727 elt = XNEW (struct edge_to_cases_elt);
729 elt->case_labels = case_label;
731 slot = htab_find_slot (edge_to_cases, elt, INSERT);
735 /* E was not in the hash table. Install E into the hash table. */
740 /* E was already in the hash table. Free ELT as we do not need it
744 /* Get the entry stored in the hash table. */
745 elt = (struct edge_to_cases_elt *) *slot;
747 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
748 TREE_CHAIN (case_label) = elt->case_labels;
749 elt->case_labels = case_label;
753 /* If we are inside a {start,end}_recording_cases block, then return
754 a chain of CASE_LABEL_EXPRs from T which reference E.
756 Otherwise return NULL. */
759 get_cases_for_edge (edge e, tree t)
761 struct edge_to_cases_elt elt, *elt_p;
766 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
767 chains available. Return NULL so the caller can detect this case. */
768 if (!recording_case_labels_p ())
773 elt.case_labels = NULL;
774 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
778 elt_p = (struct edge_to_cases_elt *)*slot;
779 return elt_p->case_labels;
782 /* If we did not find E in the hash table, then this must be the first
783 time we have been queried for information about E & T. Add all the
784 elements from T to the hash table then perform the query again. */
786 vec = SWITCH_LABELS (t);
787 n = TREE_VEC_LENGTH (vec);
788 for (i = 0; i < n; i++)
790 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
791 basic_block label_bb = label_to_block (lab);
792 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
797 /* Create the edges for a SWITCH_EXPR starting at block BB.
798 At this point, the switch body has been lowered and the
799 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
802 make_switch_expr_edges (basic_block bb)
804 tree entry = last_stmt (bb);
808 vec = SWITCH_LABELS (entry);
809 n = TREE_VEC_LENGTH (vec);
811 for (i = 0; i < n; ++i)
813 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
814 basic_block label_bb = label_to_block (lab);
815 make_edge (bb, label_bb, 0);
820 /* Return the basic block holding label DEST. */
823 label_to_block_fn (struct function *ifun, tree dest)
825 int uid = LABEL_DECL_UID (dest);
827 /* We would die hard when faced by an undefined label. Emit a label to
828 the very first basic block. This will hopefully make even the dataflow
829 and undefined variable warnings quite right. */
830 if ((errorcount || sorrycount) && uid < 0)
832 block_stmt_iterator bsi =
833 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
836 stmt = build1 (LABEL_EXPR, void_type_node, dest);
837 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
838 uid = LABEL_DECL_UID (dest);
840 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
841 <= (unsigned int) uid)
843 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
846 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
847 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
850 make_abnormal_goto_edges (basic_block bb, bool for_call)
852 basic_block target_bb;
853 block_stmt_iterator bsi;
855 FOR_EACH_BB (target_bb)
856 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
858 tree target = bsi_stmt (bsi);
860 if (TREE_CODE (target) != LABEL_EXPR)
863 target = LABEL_EXPR_LABEL (target);
865 /* Make an edge to every label block that has been marked as a
866 potential target for a computed goto or a non-local goto. */
867 if ((FORCED_LABEL (target) && !for_call)
868 || (DECL_NONLOCAL (target) && for_call))
870 make_edge (bb, target_bb, EDGE_ABNORMAL);
876 /* Create edges for a goto statement at block BB. */
879 make_goto_expr_edges (basic_block bb)
881 block_stmt_iterator last = bsi_last (bb);
882 tree goto_t = bsi_stmt (last);
884 /* A simple GOTO creates normal edges. */
885 if (simple_goto_p (goto_t))
887 tree dest = GOTO_DESTINATION (goto_t);
888 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
889 #ifdef USE_MAPPED_LOCATION
890 e->goto_locus = EXPR_LOCATION (goto_t);
892 e->goto_locus = EXPR_LOCUS (goto_t);
894 bsi_remove (&last, true);
898 /* A computed GOTO creates abnormal edges. */
899 make_abnormal_goto_edges (bb, false);
903 /*---------------------------------------------------------------------------
905 ---------------------------------------------------------------------------*/
907 /* Cleanup useless labels in basic blocks. This is something we wish
908 to do early because it allows us to group case labels before creating
909 the edges for the CFG, and it speeds up block statement iterators in
911 We only run this pass once, running it more than once is probably not
914 /* A map from basic block index to the leading label of that block. */
915 static tree *label_for_bb;
917 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
919 update_eh_label (struct eh_region *region)
921 tree old_label = get_eh_region_tree_label (region);
925 basic_block bb = label_to_block (old_label);
927 /* ??? After optimizing, there may be EH regions with labels
928 that have already been removed from the function body, so
929 there is no basic block for them. */
933 new_label = label_for_bb[bb->index];
934 set_eh_region_tree_label (region, new_label);
938 /* Given LABEL return the first label in the same basic block. */
940 main_block_label (tree label)
942 basic_block bb = label_to_block (label);
944 /* label_to_block possibly inserted undefined label into the chain. */
945 if (!label_for_bb[bb->index])
946 label_for_bb[bb->index] = label;
947 return label_for_bb[bb->index];
950 /* Cleanup redundant labels. This is a three-step process:
951 1) Find the leading label for each block.
952 2) Redirect all references to labels to the leading labels.
953 3) Cleanup all useless labels. */
956 cleanup_dead_labels (void)
959 label_for_bb = XCNEWVEC (tree, last_basic_block);
961 /* Find a suitable label for each block. We use the first user-defined
962 label if there is one, or otherwise just the first label we see. */
965 block_stmt_iterator i;
967 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
969 tree label, stmt = bsi_stmt (i);
971 if (TREE_CODE (stmt) != LABEL_EXPR)
974 label = LABEL_EXPR_LABEL (stmt);
976 /* If we have not yet seen a label for the current block,
977 remember this one and see if there are more labels. */
978 if (! label_for_bb[bb->index])
980 label_for_bb[bb->index] = label;
984 /* If we did see a label for the current block already, but it
985 is an artificially created label, replace it if the current
986 label is a user defined label. */
987 if (! DECL_ARTIFICIAL (label)
988 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
990 label_for_bb[bb->index] = label;
996 /* Now redirect all jumps/branches to the selected label.
997 First do so for each block ending in a control statement. */
1000 tree stmt = last_stmt (bb);
1004 switch (TREE_CODE (stmt))
1008 tree true_branch, false_branch;
1010 true_branch = COND_EXPR_THEN (stmt);
1011 false_branch = COND_EXPR_ELSE (stmt);
1013 GOTO_DESTINATION (true_branch)
1014 = main_block_label (GOTO_DESTINATION (true_branch));
1015 GOTO_DESTINATION (false_branch)
1016 = main_block_label (GOTO_DESTINATION (false_branch));
1024 tree vec = SWITCH_LABELS (stmt);
1025 size_t n = TREE_VEC_LENGTH (vec);
1027 /* Replace all destination labels. */
1028 for (i = 0; i < n; ++i)
1030 tree elt = TREE_VEC_ELT (vec, i);
1031 tree label = main_block_label (CASE_LABEL (elt));
1032 CASE_LABEL (elt) = label;
1037 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1038 remove them until after we've created the CFG edges. */
1040 if (! computed_goto_p (stmt))
1042 GOTO_DESTINATION (stmt)
1043 = main_block_label (GOTO_DESTINATION (stmt));
1052 for_each_eh_region (update_eh_label);
1054 /* Finally, purge dead labels. All user-defined labels and labels that
1055 can be the target of non-local gotos and labels which have their
1056 address taken are preserved. */
1059 block_stmt_iterator i;
1060 tree label_for_this_bb = label_for_bb[bb->index];
1062 if (! label_for_this_bb)
1065 for (i = bsi_start (bb); !bsi_end_p (i); )
1067 tree label, stmt = bsi_stmt (i);
1069 if (TREE_CODE (stmt) != LABEL_EXPR)
1072 label = LABEL_EXPR_LABEL (stmt);
1074 if (label == label_for_this_bb
1075 || ! DECL_ARTIFICIAL (label)
1076 || DECL_NONLOCAL (label)
1077 || FORCED_LABEL (label))
1080 bsi_remove (&i, true);
1084 free (label_for_bb);
1087 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1088 and scan the sorted vector of cases. Combine the ones jumping to the
1090 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1093 group_case_labels (void)
1099 tree stmt = last_stmt (bb);
1100 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1102 tree labels = SWITCH_LABELS (stmt);
1103 int old_size = TREE_VEC_LENGTH (labels);
1104 int i, j, new_size = old_size;
1105 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1108 /* The default label is always the last case in a switch
1109 statement after gimplification. */
1110 default_label = CASE_LABEL (default_case);
1112 /* Look for possible opportunities to merge cases.
1113 Ignore the last element of the label vector because it
1114 must be the default case. */
1116 while (i < old_size - 1)
1118 tree base_case, base_label, base_high;
1119 base_case = TREE_VEC_ELT (labels, i);
1121 gcc_assert (base_case);
1122 base_label = CASE_LABEL (base_case);
1124 /* Discard cases that have the same destination as the
1126 if (base_label == default_label)
1128 TREE_VEC_ELT (labels, i) = NULL_TREE;
1134 base_high = CASE_HIGH (base_case) ?
1135 CASE_HIGH (base_case) : CASE_LOW (base_case);
1137 /* Try to merge case labels. Break out when we reach the end
1138 of the label vector or when we cannot merge the next case
1139 label with the current one. */
1140 while (i < old_size - 1)
1142 tree merge_case = TREE_VEC_ELT (labels, i);
1143 tree merge_label = CASE_LABEL (merge_case);
1144 tree t = int_const_binop (PLUS_EXPR, base_high,
1145 integer_one_node, 1);
1147 /* Merge the cases if they jump to the same place,
1148 and their ranges are consecutive. */
1149 if (merge_label == base_label
1150 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1152 base_high = CASE_HIGH (merge_case) ?
1153 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1154 CASE_HIGH (base_case) = base_high;
1155 TREE_VEC_ELT (labels, i) = NULL_TREE;
1164 /* Compress the case labels in the label vector, and adjust the
1165 length of the vector. */
1166 for (i = 0, j = 0; i < new_size; i++)
1168 while (! TREE_VEC_ELT (labels, j))
1170 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1172 TREE_VEC_LENGTH (labels) = new_size;
1177 /* Checks whether we can merge block B into block A. */
1180 tree_can_merge_blocks_p (basic_block a, basic_block b)
1183 block_stmt_iterator bsi;
1186 if (!single_succ_p (a))
1189 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1192 if (single_succ (a) != b)
1195 if (!single_pred_p (b))
1198 if (b == EXIT_BLOCK_PTR)
1201 /* If A ends by a statement causing exceptions or something similar, we
1202 cannot merge the blocks. */
1203 stmt = last_stmt (a);
1204 if (stmt && stmt_ends_bb_p (stmt))
1207 /* Do not allow a block with only a non-local label to be merged. */
1208 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1209 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1212 /* It must be possible to eliminate all phi nodes in B. If ssa form
1213 is not up-to-date, we cannot eliminate any phis. */
1214 phi = phi_nodes (b);
1217 if (need_ssa_update_p ())
1220 for (; phi; phi = PHI_CHAIN (phi))
1221 if (!is_gimple_reg (PHI_RESULT (phi))
1222 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1226 /* Do not remove user labels. */
1227 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1229 stmt = bsi_stmt (bsi);
1230 if (TREE_CODE (stmt) != LABEL_EXPR)
1232 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1236 /* Protect the loop latches. */
1238 && b->loop_father->latch == b)
1244 /* Replaces all uses of NAME by VAL. */
1247 replace_uses_by (tree name, tree val)
1249 imm_use_iterator imm_iter;
1256 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1258 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1260 replace_exp (use, val);
1262 if (TREE_CODE (stmt) == PHI_NODE)
1264 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1265 if (e->flags & EDGE_ABNORMAL)
1267 /* This can only occur for virtual operands, since
1268 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1269 would prevent replacement. */
1270 gcc_assert (!is_gimple_reg (name));
1271 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1275 if (TREE_CODE (stmt) != PHI_NODE)
1279 fold_stmt_inplace (stmt);
1280 rhs = get_rhs (stmt);
1281 if (TREE_CODE (rhs) == ADDR_EXPR)
1282 recompute_tree_invariant_for_addr_expr (rhs);
1284 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1285 mark_new_vars_to_rename (stmt);
1289 gcc_assert (num_imm_uses (name) == 0);
1291 /* Also update the trees stored in loop structures. */
1296 for (i = 0; i < current_loops->num; i++)
1298 loop = current_loops->parray[i];
1300 substitute_in_loop_info (loop, name, val);
1305 /* Merge block B into block A. */
1308 tree_merge_blocks (basic_block a, basic_block b)
1310 block_stmt_iterator bsi;
1311 tree_stmt_iterator last;
1315 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1317 /* Remove all single-valued PHI nodes from block B of the form
1318 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1320 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1322 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1324 bool may_replace_uses = may_propagate_copy (def, use);
1326 /* In case we have loops to care about, do not propagate arguments of
1327 loop closed ssa phi nodes. */
1329 && is_gimple_reg (def)
1330 && TREE_CODE (use) == SSA_NAME
1331 && a->loop_father != b->loop_father)
1332 may_replace_uses = false;
1334 if (!may_replace_uses)
1336 gcc_assert (is_gimple_reg (def));
1338 /* Note that just emitting the copies is fine -- there is no problem
1339 with ordering of phi nodes. This is because A is the single
1340 predecessor of B, therefore results of the phi nodes cannot
1341 appear as arguments of the phi nodes. */
1342 copy = build2 (MODIFY_EXPR, void_type_node, def, use);
1343 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1344 SET_PHI_RESULT (phi, NULL_TREE);
1345 SSA_NAME_DEF_STMT (def) = copy;
1348 replace_uses_by (def, use);
1350 remove_phi_node (phi, NULL);
1353 /* Ensure that B follows A. */
1354 move_block_after (b, a);
1356 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1357 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1359 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1360 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1362 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1364 tree label = bsi_stmt (bsi);
1366 bsi_remove (&bsi, false);
1367 /* Now that we can thread computed gotos, we might have
1368 a situation where we have a forced label in block B
1369 However, the label at the start of block B might still be
1370 used in other ways (think about the runtime checking for
1371 Fortran assigned gotos). So we can not just delete the
1372 label. Instead we move the label to the start of block A. */
1373 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1375 block_stmt_iterator dest_bsi = bsi_start (a);
1376 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1381 change_bb_for_stmt (bsi_stmt (bsi), a);
1386 /* Merge the chains. */
1387 last = tsi_last (a->stmt_list);
1388 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1389 b->stmt_list = NULL;
1393 /* Return the one of two successors of BB that is not reachable by a
1394 reached by a complex edge, if there is one. Else, return BB. We use
1395 this in optimizations that use post-dominators for their heuristics,
1396 to catch the cases in C++ where function calls are involved. */
1399 single_noncomplex_succ (basic_block bb)
1402 if (EDGE_COUNT (bb->succs) != 2)
1405 e0 = EDGE_SUCC (bb, 0);
1406 e1 = EDGE_SUCC (bb, 1);
1407 if (e0->flags & EDGE_COMPLEX)
1409 if (e1->flags & EDGE_COMPLEX)
1416 /* Walk the function tree removing unnecessary statements.
1418 * Empty statement nodes are removed
1420 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1422 * Unnecessary COND_EXPRs are removed
1424 * Some unnecessary BIND_EXPRs are removed
1426 Clearly more work could be done. The trick is doing the analysis
1427 and removal fast enough to be a net improvement in compile times.
1429 Note that when we remove a control structure such as a COND_EXPR
1430 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1431 to ensure we eliminate all the useless code. */
1442 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1445 remove_useless_stmts_warn_notreached (tree stmt)
1447 if (EXPR_HAS_LOCATION (stmt))
1449 location_t loc = EXPR_LOCATION (stmt);
1450 if (LOCATION_LINE (loc) > 0)
1452 warning (0, "%Hwill never be executed", &loc);
1457 switch (TREE_CODE (stmt))
1459 case STATEMENT_LIST:
1461 tree_stmt_iterator i;
1462 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1463 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1469 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1471 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1473 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1477 case TRY_FINALLY_EXPR:
1478 case TRY_CATCH_EXPR:
1479 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1481 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1486 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1487 case EH_FILTER_EXPR:
1488 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1490 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1493 /* Not a live container. */
1501 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1503 tree then_clause, else_clause, cond;
1504 bool save_has_label, then_has_label, else_has_label;
1506 save_has_label = data->has_label;
1507 data->has_label = false;
1508 data->last_goto = NULL;
1510 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1512 then_has_label = data->has_label;
1513 data->has_label = false;
1514 data->last_goto = NULL;
1516 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1518 else_has_label = data->has_label;
1519 data->has_label = save_has_label | then_has_label | else_has_label;
1521 then_clause = COND_EXPR_THEN (*stmt_p);
1522 else_clause = COND_EXPR_ELSE (*stmt_p);
1523 cond = fold (COND_EXPR_COND (*stmt_p));
1525 /* If neither arm does anything at all, we can remove the whole IF. */
1526 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1528 *stmt_p = build_empty_stmt ();
1529 data->repeat = true;
1532 /* If there are no reachable statements in an arm, then we can
1533 zap the entire conditional. */
1534 else if (integer_nonzerop (cond) && !else_has_label)
1536 if (warn_notreached)
1537 remove_useless_stmts_warn_notreached (else_clause);
1538 *stmt_p = then_clause;
1539 data->repeat = true;
1541 else if (integer_zerop (cond) && !then_has_label)
1543 if (warn_notreached)
1544 remove_useless_stmts_warn_notreached (then_clause);
1545 *stmt_p = else_clause;
1546 data->repeat = true;
1549 /* Check a couple of simple things on then/else with single stmts. */
1552 tree then_stmt = expr_only (then_clause);
1553 tree else_stmt = expr_only (else_clause);
1555 /* Notice branches to a common destination. */
1556 if (then_stmt && else_stmt
1557 && TREE_CODE (then_stmt) == GOTO_EXPR
1558 && TREE_CODE (else_stmt) == GOTO_EXPR
1559 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1561 *stmt_p = then_stmt;
1562 data->repeat = true;
1565 /* If the THEN/ELSE clause merely assigns a value to a variable or
1566 parameter which is already known to contain that value, then
1567 remove the useless THEN/ELSE clause. */
1568 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1571 && TREE_CODE (else_stmt) == MODIFY_EXPR
1572 && TREE_OPERAND (else_stmt, 0) == cond
1573 && integer_zerop (TREE_OPERAND (else_stmt, 1)))
1574 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1576 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1577 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1578 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1579 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1581 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1582 ? then_stmt : else_stmt);
1583 tree *location = (TREE_CODE (cond) == EQ_EXPR
1584 ? &COND_EXPR_THEN (*stmt_p)
1585 : &COND_EXPR_ELSE (*stmt_p));
1588 && TREE_CODE (stmt) == MODIFY_EXPR
1589 && TREE_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1590 && TREE_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1591 *location = alloc_stmt_list ();
1595 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1596 would be re-introduced during lowering. */
1597 data->last_goto = NULL;
1602 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1604 bool save_may_branch, save_may_throw;
1605 bool this_may_branch, this_may_throw;
1607 /* Collect may_branch and may_throw information for the body only. */
1608 save_may_branch = data->may_branch;
1609 save_may_throw = data->may_throw;
1610 data->may_branch = false;
1611 data->may_throw = false;
1612 data->last_goto = NULL;
1614 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1616 this_may_branch = data->may_branch;
1617 this_may_throw = data->may_throw;
1618 data->may_branch |= save_may_branch;
1619 data->may_throw |= save_may_throw;
1620 data->last_goto = NULL;
1622 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1624 /* If the body is empty, then we can emit the FINALLY block without
1625 the enclosing TRY_FINALLY_EXPR. */
1626 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1628 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1629 data->repeat = true;
1632 /* If the handler is empty, then we can emit the TRY block without
1633 the enclosing TRY_FINALLY_EXPR. */
1634 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1636 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1637 data->repeat = true;
1640 /* If the body neither throws, nor branches, then we can safely
1641 string the TRY and FINALLY blocks together. */
1642 else if (!this_may_branch && !this_may_throw)
1644 tree stmt = *stmt_p;
1645 *stmt_p = TREE_OPERAND (stmt, 0);
1646 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1647 data->repeat = true;
1653 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1655 bool save_may_throw, this_may_throw;
1656 tree_stmt_iterator i;
1659 /* Collect may_throw information for the body only. */
1660 save_may_throw = data->may_throw;
1661 data->may_throw = false;
1662 data->last_goto = NULL;
1664 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1666 this_may_throw = data->may_throw;
1667 data->may_throw = save_may_throw;
1669 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1670 if (!this_may_throw)
1672 if (warn_notreached)
1673 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1674 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1675 data->repeat = true;
1679 /* Process the catch clause specially. We may be able to tell that
1680 no exceptions propagate past this point. */
1682 this_may_throw = true;
1683 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1684 stmt = tsi_stmt (i);
1685 data->last_goto = NULL;
1687 switch (TREE_CODE (stmt))
1690 for (; !tsi_end_p (i); tsi_next (&i))
1692 stmt = tsi_stmt (i);
1693 /* If we catch all exceptions, then the body does not
1694 propagate exceptions past this point. */
1695 if (CATCH_TYPES (stmt) == NULL)
1696 this_may_throw = false;
1697 data->last_goto = NULL;
1698 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1702 case EH_FILTER_EXPR:
1703 if (EH_FILTER_MUST_NOT_THROW (stmt))
1704 this_may_throw = false;
1705 else if (EH_FILTER_TYPES (stmt) == NULL)
1706 this_may_throw = false;
1707 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1711 /* Otherwise this is a cleanup. */
1712 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1714 /* If the cleanup is empty, then we can emit the TRY block without
1715 the enclosing TRY_CATCH_EXPR. */
1716 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1718 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1719 data->repeat = true;
1723 data->may_throw |= this_may_throw;
1728 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1732 /* First remove anything underneath the BIND_EXPR. */
1733 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1735 /* If the BIND_EXPR has no variables, then we can pull everything
1736 up one level and remove the BIND_EXPR, unless this is the toplevel
1737 BIND_EXPR for the current function or an inlined function.
1739 When this situation occurs we will want to apply this
1740 optimization again. */
1741 block = BIND_EXPR_BLOCK (*stmt_p);
1742 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1743 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1745 || ! BLOCK_ABSTRACT_ORIGIN (block)
1746 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1749 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1750 data->repeat = true;
1756 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1758 tree dest = GOTO_DESTINATION (*stmt_p);
1760 data->may_branch = true;
1761 data->last_goto = NULL;
1763 /* Record the last goto expr, so that we can delete it if unnecessary. */
1764 if (TREE_CODE (dest) == LABEL_DECL)
1765 data->last_goto = stmt_p;
1770 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1772 tree label = LABEL_EXPR_LABEL (*stmt_p);
1774 data->has_label = true;
1776 /* We do want to jump across non-local label receiver code. */
1777 if (DECL_NONLOCAL (label))
1778 data->last_goto = NULL;
1780 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1782 *data->last_goto = build_empty_stmt ();
1783 data->repeat = true;
1786 /* ??? Add something here to delete unused labels. */
1790 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1791 decl. This allows us to eliminate redundant or useless
1792 calls to "const" functions.
1794 Gimplifier already does the same operation, but we may notice functions
1795 being const and pure once their calls has been gimplified, so we need
1796 to update the flag. */
1799 update_call_expr_flags (tree call)
1801 tree decl = get_callee_fndecl (call);
1804 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1805 TREE_SIDE_EFFECTS (call) = 0;
1806 if (TREE_NOTHROW (decl))
1807 TREE_NOTHROW (call) = 1;
1811 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1814 notice_special_calls (tree t)
1816 int flags = call_expr_flags (t);
1818 if (flags & ECF_MAY_BE_ALLOCA)
1819 current_function_calls_alloca = true;
1820 if (flags & ECF_RETURNS_TWICE)
1821 current_function_calls_setjmp = true;
1825 /* Clear flags set by notice_special_calls. Used by dead code removal
1826 to update the flags. */
1829 clear_special_calls (void)
1831 current_function_calls_alloca = false;
1832 current_function_calls_setjmp = false;
1837 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1841 switch (TREE_CODE (t))
1844 remove_useless_stmts_cond (tp, data);
1847 case TRY_FINALLY_EXPR:
1848 remove_useless_stmts_tf (tp, data);
1851 case TRY_CATCH_EXPR:
1852 remove_useless_stmts_tc (tp, data);
1856 remove_useless_stmts_bind (tp, data);
1860 remove_useless_stmts_goto (tp, data);
1864 remove_useless_stmts_label (tp, data);
1869 data->last_goto = NULL;
1870 data->may_branch = true;
1875 data->last_goto = NULL;
1876 notice_special_calls (t);
1877 update_call_expr_flags (t);
1878 if (tree_could_throw_p (t))
1879 data->may_throw = true;
1883 data->last_goto = NULL;
1885 op = get_call_expr_in (t);
1888 update_call_expr_flags (op);
1889 notice_special_calls (op);
1891 if (tree_could_throw_p (t))
1892 data->may_throw = true;
1895 case STATEMENT_LIST:
1897 tree_stmt_iterator i = tsi_start (t);
1898 while (!tsi_end_p (i))
1901 if (IS_EMPTY_STMT (t))
1907 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1910 if (TREE_CODE (t) == STATEMENT_LIST)
1912 tsi_link_before (&i, t, TSI_SAME_STMT);
1922 data->last_goto = NULL;
1926 data->last_goto = NULL;
1932 remove_useless_stmts (void)
1934 struct rus_data data;
1936 clear_special_calls ();
1940 memset (&data, 0, sizeof (data));
1941 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1943 while (data.repeat);
1948 struct tree_opt_pass pass_remove_useless_stmts =
1950 "useless", /* name */
1952 remove_useless_stmts, /* execute */
1955 0, /* static_pass_number */
1957 PROP_gimple_any, /* properties_required */
1958 0, /* properties_provided */
1959 0, /* properties_destroyed */
1960 0, /* todo_flags_start */
1961 TODO_dump_func, /* todo_flags_finish */
1965 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1968 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1972 /* Since this block is no longer reachable, we can just delete all
1973 of its PHI nodes. */
1974 phi = phi_nodes (bb);
1977 tree next = PHI_CHAIN (phi);
1978 remove_phi_node (phi, NULL_TREE);
1982 /* Remove edges to BB's successors. */
1983 while (EDGE_COUNT (bb->succs) > 0)
1984 remove_edge (EDGE_SUCC (bb, 0));
1988 /* Remove statements of basic block BB. */
1991 remove_bb (basic_block bb)
1993 block_stmt_iterator i;
1994 #ifdef USE_MAPPED_LOCATION
1995 source_location loc = UNKNOWN_LOCATION;
1997 source_locus loc = 0;
2002 fprintf (dump_file, "Removing basic block %d\n", bb->index);
2003 if (dump_flags & TDF_DETAILS)
2005 dump_bb (bb, dump_file, 0);
2006 fprintf (dump_file, "\n");
2010 /* If we remove the header or the latch of a loop, mark the loop for
2011 removal by setting its header and latch to NULL. */
2014 struct loop *loop = bb->loop_father;
2016 if (loop->latch == bb
2017 || loop->header == bb)
2020 loop->header = NULL;
2022 /* Also clean up the information associated with the loop. Updating
2023 it would waste time. More importantly, it may refer to ssa
2024 names that were defined in other removed basic block -- these
2025 ssa names are now removed and invalid. */
2026 free_numbers_of_iterations_estimates_loop (loop);
2030 /* Remove all the instructions in the block. */
2031 for (i = bsi_start (bb); !bsi_end_p (i);)
2033 tree stmt = bsi_stmt (i);
2034 if (TREE_CODE (stmt) == LABEL_EXPR
2035 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2036 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2039 block_stmt_iterator new_bsi;
2041 /* A non-reachable non-local label may still be referenced.
2042 But it no longer needs to carry the extra semantics of
2044 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2046 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2047 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2050 new_bb = bb->prev_bb;
2051 new_bsi = bsi_start (new_bb);
2052 bsi_remove (&i, false);
2053 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2057 /* Release SSA definitions if we are in SSA. Note that we
2058 may be called when not in SSA. For example,
2059 final_cleanup calls this function via
2060 cleanup_tree_cfg. */
2062 release_defs (stmt);
2064 bsi_remove (&i, true);
2067 /* Don't warn for removed gotos. Gotos are often removed due to
2068 jump threading, thus resulting in bogus warnings. Not great,
2069 since this way we lose warnings for gotos in the original
2070 program that are indeed unreachable. */
2071 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2073 #ifdef USE_MAPPED_LOCATION
2074 if (EXPR_HAS_LOCATION (stmt))
2075 loc = EXPR_LOCATION (stmt);
2078 t = EXPR_LOCUS (stmt);
2079 if (t && LOCATION_LINE (*t) > 0)
2085 /* If requested, give a warning that the first statement in the
2086 block is unreachable. We walk statements backwards in the
2087 loop above, so the last statement we process is the first statement
2089 #ifdef USE_MAPPED_LOCATION
2090 if (loc > BUILTINS_LOCATION)
2091 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2094 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2097 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2101 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2102 predicate VAL, return the edge that will be taken out of the block.
2103 If VAL does not match a unique edge, NULL is returned. */
2106 find_taken_edge (basic_block bb, tree val)
2110 stmt = last_stmt (bb);
2113 gcc_assert (is_ctrl_stmt (stmt));
2116 if (! is_gimple_min_invariant (val))
2119 if (TREE_CODE (stmt) == COND_EXPR)
2120 return find_taken_edge_cond_expr (bb, val);
2122 if (TREE_CODE (stmt) == SWITCH_EXPR)
2123 return find_taken_edge_switch_expr (bb, val);
2125 if (computed_goto_p (stmt))
2127 /* Only optimize if the argument is a label, if the argument is
2128 not a label then we can not construct a proper CFG.
2130 It may be the case that we only need to allow the LABEL_REF to
2131 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2132 appear inside a LABEL_EXPR just to be safe. */
2133 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2134 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2135 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2142 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2143 statement, determine which of the outgoing edges will be taken out of the
2144 block. Return NULL if either edge may be taken. */
2147 find_taken_edge_computed_goto (basic_block bb, tree val)
2152 dest = label_to_block (val);
2155 e = find_edge (bb, dest);
2156 gcc_assert (e != NULL);
2162 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2163 statement, determine which of the two edges will be taken out of the
2164 block. Return NULL if either edge may be taken. */
2167 find_taken_edge_cond_expr (basic_block bb, tree val)
2169 edge true_edge, false_edge;
2171 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2173 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2174 return (zero_p (val) ? false_edge : true_edge);
2177 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2178 statement, determine which edge will be taken out of the block. Return
2179 NULL if any edge may be taken. */
2182 find_taken_edge_switch_expr (basic_block bb, tree val)
2184 tree switch_expr, taken_case;
2185 basic_block dest_bb;
2188 switch_expr = last_stmt (bb);
2189 taken_case = find_case_label_for_value (switch_expr, val);
2190 dest_bb = label_to_block (CASE_LABEL (taken_case));
2192 e = find_edge (bb, dest_bb);
2198 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2199 We can make optimal use here of the fact that the case labels are
2200 sorted: We can do a binary search for a case matching VAL. */
2203 find_case_label_for_value (tree switch_expr, tree val)
2205 tree vec = SWITCH_LABELS (switch_expr);
2206 size_t low, high, n = TREE_VEC_LENGTH (vec);
2207 tree default_case = TREE_VEC_ELT (vec, n - 1);
2209 for (low = -1, high = n - 1; high - low > 1; )
2211 size_t i = (high + low) / 2;
2212 tree t = TREE_VEC_ELT (vec, i);
2215 /* Cache the result of comparing CASE_LOW and val. */
2216 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2223 if (CASE_HIGH (t) == NULL)
2225 /* A singe-valued case label. */
2231 /* A case range. We can only handle integer ranges. */
2232 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2237 return default_case;
2243 /*---------------------------------------------------------------------------
2245 ---------------------------------------------------------------------------*/
2247 /* Dump tree-specific information of block BB to file OUTF. */
2250 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2252 dump_generic_bb (outf, bb, indent, TDF_VOPS);
2256 /* Dump a basic block on stderr. */
2259 debug_tree_bb (basic_block bb)
2261 dump_bb (bb, stderr, 0);
2265 /* Dump basic block with index N on stderr. */
2268 debug_tree_bb_n (int n)
2270 debug_tree_bb (BASIC_BLOCK (n));
2271 return BASIC_BLOCK (n);
2275 /* Dump the CFG on stderr.
2277 FLAGS are the same used by the tree dumping functions
2278 (see TDF_* in tree-pass.h). */
2281 debug_tree_cfg (int flags)
2283 dump_tree_cfg (stderr, flags);
2287 /* Dump the program showing basic block boundaries on the given FILE.
2289 FLAGS are the same used by the tree dumping functions (see TDF_* in
2293 dump_tree_cfg (FILE *file, int flags)
2295 if (flags & TDF_DETAILS)
2297 const char *funcname
2298 = lang_hooks.decl_printable_name (current_function_decl, 2);
2301 fprintf (file, ";; Function %s\n\n", funcname);
2302 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2303 n_basic_blocks, n_edges, last_basic_block);
2305 brief_dump_cfg (file);
2306 fprintf (file, "\n");
2309 if (flags & TDF_STATS)
2310 dump_cfg_stats (file);
2312 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2316 /* Dump CFG statistics on FILE. */
2319 dump_cfg_stats (FILE *file)
2321 static long max_num_merged_labels = 0;
2322 unsigned long size, total = 0;
2325 const char * const fmt_str = "%-30s%-13s%12s\n";
2326 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2327 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2328 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2329 const char *funcname
2330 = lang_hooks.decl_printable_name (current_function_decl, 2);
2333 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2335 fprintf (file, "---------------------------------------------------------\n");
2336 fprintf (file, fmt_str, "", " Number of ", "Memory");
2337 fprintf (file, fmt_str, "", " instances ", "used ");
2338 fprintf (file, "---------------------------------------------------------\n");
2340 size = n_basic_blocks * sizeof (struct basic_block_def);
2342 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2343 SCALE (size), LABEL (size));
2347 num_edges += EDGE_COUNT (bb->succs);
2348 size = num_edges * sizeof (struct edge_def);
2350 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2352 fprintf (file, "---------------------------------------------------------\n");
2353 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2355 fprintf (file, "---------------------------------------------------------\n");
2356 fprintf (file, "\n");
2358 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2359 max_num_merged_labels = cfg_stats.num_merged_labels;
2361 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2362 cfg_stats.num_merged_labels, max_num_merged_labels);
2364 fprintf (file, "\n");
2368 /* Dump CFG statistics on stderr. Keep extern so that it's always
2369 linked in the final executable. */
2372 debug_cfg_stats (void)
2374 dump_cfg_stats (stderr);
2378 /* Dump the flowgraph to a .vcg FILE. */
2381 tree_cfg2vcg (FILE *file)
2386 const char *funcname
2387 = lang_hooks.decl_printable_name (current_function_decl, 2);
2389 /* Write the file header. */
2390 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2391 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2392 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2394 /* Write blocks and edges. */
2395 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2397 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2400 if (e->flags & EDGE_FAKE)
2401 fprintf (file, " linestyle: dotted priority: 10");
2403 fprintf (file, " linestyle: solid priority: 100");
2405 fprintf (file, " }\n");
2411 enum tree_code head_code, end_code;
2412 const char *head_name, *end_name;
2415 tree first = first_stmt (bb);
2416 tree last = last_stmt (bb);
2420 head_code = TREE_CODE (first);
2421 head_name = tree_code_name[head_code];
2422 head_line = get_lineno (first);
2425 head_name = "no-statement";
2429 end_code = TREE_CODE (last);
2430 end_name = tree_code_name[end_code];
2431 end_line = get_lineno (last);
2434 end_name = "no-statement";
2436 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2437 bb->index, bb->index, head_name, head_line, end_name,
2440 FOR_EACH_EDGE (e, ei, bb->succs)
2442 if (e->dest == EXIT_BLOCK_PTR)
2443 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2445 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2447 if (e->flags & EDGE_FAKE)
2448 fprintf (file, " priority: 10 linestyle: dotted");
2450 fprintf (file, " priority: 100 linestyle: solid");
2452 fprintf (file, " }\n");
2455 if (bb->next_bb != EXIT_BLOCK_PTR)
2459 fputs ("}\n\n", file);
2464 /*---------------------------------------------------------------------------
2465 Miscellaneous helpers
2466 ---------------------------------------------------------------------------*/
2468 /* Return true if T represents a stmt that always transfers control. */
2471 is_ctrl_stmt (tree t)
2473 return (TREE_CODE (t) == COND_EXPR
2474 || TREE_CODE (t) == SWITCH_EXPR
2475 || TREE_CODE (t) == GOTO_EXPR
2476 || TREE_CODE (t) == RETURN_EXPR
2477 || TREE_CODE (t) == RESX_EXPR);
2481 /* Return true if T is a statement that may alter the flow of control
2482 (e.g., a call to a non-returning function). */
2485 is_ctrl_altering_stmt (tree t)
2490 call = get_call_expr_in (t);
2493 /* A non-pure/const CALL_EXPR alters flow control if the current
2494 function has nonlocal labels. */
2495 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2498 /* A CALL_EXPR also alters control flow if it does not return. */
2499 if (call_expr_flags (call) & ECF_NORETURN)
2503 /* OpenMP directives alter control flow. */
2504 if (OMP_DIRECTIVE_P (t))
2507 /* If a statement can throw, it alters control flow. */
2508 return tree_can_throw_internal (t);
2512 /* Return true if T is a computed goto. */
2515 computed_goto_p (tree t)
2517 return (TREE_CODE (t) == GOTO_EXPR
2518 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2522 /* Return true if T is a simple local goto. */
2525 simple_goto_p (tree t)
2527 return (TREE_CODE (t) == GOTO_EXPR
2528 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2532 /* Return true if T can make an abnormal transfer of control flow.
2533 Transfers of control flow associated with EH are excluded. */
2536 tree_can_make_abnormal_goto (tree t)
2538 if (computed_goto_p (t))
2540 if (TREE_CODE (t) == MODIFY_EXPR)
2541 t = TREE_OPERAND (t, 1);
2542 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2543 t = TREE_OPERAND (t, 0);
2544 if (TREE_CODE (t) == CALL_EXPR)
2545 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2550 /* Return true if T should start a new basic block. PREV_T is the
2551 statement preceding T. It is used when T is a label or a case label.
2552 Labels should only start a new basic block if their previous statement
2553 wasn't a label. Otherwise, sequence of labels would generate
2554 unnecessary basic blocks that only contain a single label. */
2557 stmt_starts_bb_p (tree t, tree prev_t)
2562 /* LABEL_EXPRs start a new basic block only if the preceding
2563 statement wasn't a label of the same type. This prevents the
2564 creation of consecutive blocks that have nothing but a single
2566 if (TREE_CODE (t) == LABEL_EXPR)
2568 /* Nonlocal and computed GOTO targets always start a new block. */
2569 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2570 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2573 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2575 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2578 cfg_stats.num_merged_labels++;
2589 /* Return true if T should end a basic block. */
2592 stmt_ends_bb_p (tree t)
2594 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2598 /* Add gotos that used to be represented implicitly in the CFG. */
2601 disband_implicit_edges (void)
2604 block_stmt_iterator last;
2611 last = bsi_last (bb);
2612 stmt = last_stmt (bb);
2614 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2616 /* Remove superfluous gotos from COND_EXPR branches. Moved
2617 from cfg_remove_useless_stmts here since it violates the
2618 invariants for tree--cfg correspondence and thus fits better
2619 here where we do it anyway. */
2620 e = find_edge (bb, bb->next_bb);
2623 if (e->flags & EDGE_TRUE_VALUE)
2624 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2625 else if (e->flags & EDGE_FALSE_VALUE)
2626 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2629 e->flags |= EDGE_FALLTHRU;
2635 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2637 /* Remove the RETURN_EXPR if we may fall though to the exit
2639 gcc_assert (single_succ_p (bb));
2640 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2642 if (bb->next_bb == EXIT_BLOCK_PTR
2643 && !TREE_OPERAND (stmt, 0))
2645 bsi_remove (&last, true);
2646 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2651 /* There can be no fallthru edge if the last statement is a control
2653 if (stmt && is_ctrl_stmt (stmt))
2656 /* Find a fallthru edge and emit the goto if necessary. */
2657 FOR_EACH_EDGE (e, ei, bb->succs)
2658 if (e->flags & EDGE_FALLTHRU)
2661 if (!e || e->dest == bb->next_bb)
2664 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2665 label = tree_block_label (e->dest);
2667 stmt = build1 (GOTO_EXPR, void_type_node, label);
2668 #ifdef USE_MAPPED_LOCATION
2669 SET_EXPR_LOCATION (stmt, e->goto_locus);
2671 SET_EXPR_LOCUS (stmt, e->goto_locus);
2673 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2674 e->flags &= ~EDGE_FALLTHRU;
2678 /* Remove block annotations and other datastructures. */
2681 delete_tree_cfg_annotations (void)
2683 label_to_block_map = NULL;
2687 /* Return the first statement in basic block BB. */
2690 first_stmt (basic_block bb)
2692 block_stmt_iterator i = bsi_start (bb);
2693 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2697 /* Return the last statement in basic block BB. */
2700 last_stmt (basic_block bb)
2702 block_stmt_iterator b = bsi_last (bb);
2703 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2707 /* Return a pointer to the last statement in block BB. */
2710 last_stmt_ptr (basic_block bb)
2712 block_stmt_iterator last = bsi_last (bb);
2713 return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL;
2717 /* Return the last statement of an otherwise empty block. Return NULL
2718 if the block is totally empty, or if it contains more than one
2722 last_and_only_stmt (basic_block bb)
2724 block_stmt_iterator i = bsi_last (bb);
2730 last = bsi_stmt (i);
2735 /* Empty statements should no longer appear in the instruction stream.
2736 Everything that might have appeared before should be deleted by
2737 remove_useless_stmts, and the optimizers should just bsi_remove
2738 instead of smashing with build_empty_stmt.
2740 Thus the only thing that should appear here in a block containing
2741 one executable statement is a label. */
2742 prev = bsi_stmt (i);
2743 if (TREE_CODE (prev) == LABEL_EXPR)
2750 /* Mark BB as the basic block holding statement T. */
2753 set_bb_for_stmt (tree t, basic_block bb)
2755 if (TREE_CODE (t) == PHI_NODE)
2757 else if (TREE_CODE (t) == STATEMENT_LIST)
2759 tree_stmt_iterator i;
2760 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2761 set_bb_for_stmt (tsi_stmt (i), bb);
2765 stmt_ann_t ann = get_stmt_ann (t);
2768 /* If the statement is a label, add the label to block-to-labels map
2769 so that we can speed up edge creation for GOTO_EXPRs. */
2770 if (TREE_CODE (t) == LABEL_EXPR)
2774 t = LABEL_EXPR_LABEL (t);
2775 uid = LABEL_DECL_UID (t);
2778 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2779 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2780 if (old_len <= (unsigned) uid)
2783 unsigned new_len = 3 * uid / 2;
2785 VEC_safe_grow (basic_block, gc, label_to_block_map,
2787 addr = VEC_address (basic_block, label_to_block_map);
2788 memset (&addr[old_len],
2789 0, sizeof (basic_block) * (new_len - old_len));
2793 /* We're moving an existing label. Make sure that we've
2794 removed it from the old block. */
2796 || !VEC_index (basic_block, label_to_block_map, uid));
2797 VEC_replace (basic_block, label_to_block_map, uid, bb);
2802 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2803 from one basic block to another.
2804 For BB splitting we can run into quadratic case, so performance is quite
2805 important and knowing that the tables are big enough, change_bb_for_stmt
2806 can inline as leaf function. */
2808 change_bb_for_stmt (tree t, basic_block bb)
2810 get_stmt_ann (t)->bb = bb;
2811 if (TREE_CODE (t) == LABEL_EXPR)
2812 VEC_replace (basic_block, label_to_block_map,
2813 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2816 /* Finds iterator for STMT. */
2818 extern block_stmt_iterator
2819 bsi_for_stmt (tree stmt)
2821 block_stmt_iterator bsi;
2823 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2824 if (bsi_stmt (bsi) == stmt)
2830 /* Mark statement T as modified, and update it. */
2832 update_modified_stmts (tree t)
2834 if (TREE_CODE (t) == STATEMENT_LIST)
2836 tree_stmt_iterator i;
2838 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2840 stmt = tsi_stmt (i);
2841 update_stmt_if_modified (stmt);
2845 update_stmt_if_modified (t);
2848 /* Insert statement (or statement list) T before the statement
2849 pointed-to by iterator I. M specifies how to update iterator I
2850 after insertion (see enum bsi_iterator_update). */
2853 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2855 set_bb_for_stmt (t, i->bb);
2856 update_modified_stmts (t);
2857 tsi_link_before (&i->tsi, t, (enum tsi_iterator_update) m);
2861 /* Insert statement (or statement list) T after the statement
2862 pointed-to by iterator I. M specifies how to update iterator I
2863 after insertion (see enum bsi_iterator_update). */
2866 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2868 set_bb_for_stmt (t, i->bb);
2869 update_modified_stmts (t);
2870 tsi_link_after (&i->tsi, t, (enum tsi_iterator_update) m);
2874 /* Remove the statement pointed to by iterator I. The iterator is updated
2875 to the next statement.
2877 When REMOVE_EH_INFO is true we remove the statement pointed to by
2878 iterator I from the EH tables. Otherwise we do not modify the EH
2881 Generally, REMOVE_EH_INFO should be true when the statement is going to
2882 be removed from the IL and not reinserted elsewhere. */
2885 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2887 tree t = bsi_stmt (*i);
2888 set_bb_for_stmt (t, NULL);
2889 delink_stmt_imm_use (t);
2890 tsi_delink (&i->tsi);
2891 mark_stmt_modified (t);
2893 remove_stmt_from_eh_region (t);
2897 /* Move the statement at FROM so it comes right after the statement at TO. */
2900 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2902 tree stmt = bsi_stmt (*from);
2903 bsi_remove (from, false);
2904 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2908 /* Move the statement at FROM so it comes right before the statement at TO. */
2911 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2913 tree stmt = bsi_stmt (*from);
2914 bsi_remove (from, false);
2915 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2919 /* Move the statement at FROM to the end of basic block BB. */
2922 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2924 block_stmt_iterator last = bsi_last (bb);
2926 /* Have to check bsi_end_p because it could be an empty block. */
2927 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2928 bsi_move_before (from, &last);
2930 bsi_move_after (from, &last);
2934 /* Replace the contents of the statement pointed to by iterator BSI
2935 with STMT. If UPDATE_EH_INFO is true, the exception handling
2936 information of the original statement is moved to the new statement. */
2939 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2942 tree orig_stmt = bsi_stmt (*bsi);
2944 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2945 set_bb_for_stmt (stmt, bsi->bb);
2947 /* Preserve EH region information from the original statement, if
2948 requested by the caller. */
2951 eh_region = lookup_stmt_eh_region (orig_stmt);
2954 remove_stmt_from_eh_region (orig_stmt);
2955 add_stmt_to_eh_region (stmt, eh_region);
2959 delink_stmt_imm_use (orig_stmt);
2960 *bsi_stmt_ptr (*bsi) = stmt;
2961 mark_stmt_modified (stmt);
2962 update_modified_stmts (stmt);
2966 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2967 is made to place the statement in an existing basic block, but
2968 sometimes that isn't possible. When it isn't possible, the edge is
2969 split and the statement is added to the new block.
2971 In all cases, the returned *BSI points to the correct location. The
2972 return value is true if insertion should be done after the location,
2973 or false if it should be done before the location. If new basic block
2974 has to be created, it is stored in *NEW_BB. */
2977 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2978 basic_block *new_bb)
2980 basic_block dest, src;
2986 /* If the destination has one predecessor which has no PHI nodes,
2987 insert there. Except for the exit block.
2989 The requirement for no PHI nodes could be relaxed. Basically we
2990 would have to examine the PHIs to prove that none of them used
2991 the value set by the statement we want to insert on E. That
2992 hardly seems worth the effort. */
2993 if (single_pred_p (dest)
2994 && ! phi_nodes (dest)
2995 && dest != EXIT_BLOCK_PTR)
2997 *bsi = bsi_start (dest);
2998 if (bsi_end_p (*bsi))
3001 /* Make sure we insert after any leading labels. */
3002 tmp = bsi_stmt (*bsi);
3003 while (TREE_CODE (tmp) == LABEL_EXPR)
3006 if (bsi_end_p (*bsi))
3008 tmp = bsi_stmt (*bsi);
3011 if (bsi_end_p (*bsi))
3013 *bsi = bsi_last (dest);
3020 /* If the source has one successor, the edge is not abnormal and
3021 the last statement does not end a basic block, insert there.
3022 Except for the entry block. */
3024 if ((e->flags & EDGE_ABNORMAL) == 0
3025 && single_succ_p (src)
3026 && src != ENTRY_BLOCK_PTR)
3028 *bsi = bsi_last (src);
3029 if (bsi_end_p (*bsi))
3032 tmp = bsi_stmt (*bsi);
3033 if (!stmt_ends_bb_p (tmp))
3036 /* Insert code just before returning the value. We may need to decompose
3037 the return in the case it contains non-trivial operand. */
3038 if (TREE_CODE (tmp) == RETURN_EXPR)
3040 tree op = TREE_OPERAND (tmp, 0);
3041 if (op && !is_gimple_val (op))
3043 gcc_assert (TREE_CODE (op) == MODIFY_EXPR);
3044 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3045 TREE_OPERAND (tmp, 0) = TREE_OPERAND (op, 0);
3052 /* Otherwise, create a new basic block, and split this edge. */
3053 dest = split_edge (e);
3056 e = single_pred_edge (dest);
3061 /* This routine will commit all pending edge insertions, creating any new
3062 basic blocks which are necessary. */
3065 bsi_commit_edge_inserts (void)
3071 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3074 FOR_EACH_EDGE (e, ei, bb->succs)
3075 bsi_commit_one_edge_insert (e, NULL);
3079 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3080 to this block, otherwise set it to NULL. */
3083 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3087 if (PENDING_STMT (e))
3089 block_stmt_iterator bsi;
3090 tree stmt = PENDING_STMT (e);
3092 PENDING_STMT (e) = NULL_TREE;
3094 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3095 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3097 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3102 /* Add STMT to the pending list of edge E. No actual insertion is
3103 made until a call to bsi_commit_edge_inserts () is made. */
3106 bsi_insert_on_edge (edge e, tree stmt)
3108 append_to_statement_list (stmt, &PENDING_STMT (e));
3111 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3112 block has to be created, it is returned. */
3115 bsi_insert_on_edge_immediate (edge e, tree stmt)
3117 block_stmt_iterator bsi;
3118 basic_block new_bb = NULL;
3120 gcc_assert (!PENDING_STMT (e));
3122 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3123 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3125 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3130 /*---------------------------------------------------------------------------
3131 Tree specific functions for CFG manipulation
3132 ---------------------------------------------------------------------------*/
3134 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3137 reinstall_phi_args (edge new_edge, edge old_edge)
3141 if (!PENDING_STMT (old_edge))
3144 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3146 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3148 tree result = TREE_PURPOSE (var);
3149 tree arg = TREE_VALUE (var);
3151 gcc_assert (result == PHI_RESULT (phi));
3153 add_phi_arg (phi, arg, new_edge);
3156 PENDING_STMT (old_edge) = NULL;
3159 /* Returns the basic block after which the new basic block created
3160 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3161 near its "logical" location. This is of most help to humans looking
3162 at debugging dumps. */
3165 split_edge_bb_loc (edge edge_in)
3167 basic_block dest = edge_in->dest;
3169 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3170 return edge_in->src;
3172 return dest->prev_bb;
3175 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3176 Abort on abnormal edges. */
3179 tree_split_edge (edge edge_in)
3181 basic_block new_bb, after_bb, dest;
3184 /* Abnormal edges cannot be split. */
3185 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3187 dest = edge_in->dest;
3189 after_bb = split_edge_bb_loc (edge_in);
3191 new_bb = create_empty_bb (after_bb);
3192 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3193 new_bb->count = edge_in->count;
3194 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3195 new_edge->probability = REG_BR_PROB_BASE;
3196 new_edge->count = edge_in->count;
3198 e = redirect_edge_and_branch (edge_in, new_bb);
3200 reinstall_phi_args (new_edge, e);
3206 /* Return true when BB has label LABEL in it. */
3209 has_label_p (basic_block bb, tree label)
3211 block_stmt_iterator bsi;
3213 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3215 tree stmt = bsi_stmt (bsi);
3217 if (TREE_CODE (stmt) != LABEL_EXPR)
3219 if (LABEL_EXPR_LABEL (stmt) == label)
3226 /* Callback for walk_tree, check that all elements with address taken are
3227 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3228 inside a PHI node. */
3231 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3234 bool in_phi = (data != NULL);
3239 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3240 #define CHECK_OP(N, MSG) \
3241 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3242 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3244 switch (TREE_CODE (t))
3247 if (SSA_NAME_IN_FREE_LIST (t))
3249 error ("SSA name in freelist but still referenced");
3255 x = fold (ASSERT_EXPR_COND (t));
3256 if (x == boolean_false_node)
3258 error ("ASSERT_EXPR with an always-false condition");
3264 x = TREE_OPERAND (t, 0);
3265 if (TREE_CODE (x) == BIT_FIELD_REF
3266 && is_gimple_reg (TREE_OPERAND (x, 0)))
3268 error ("GIMPLE register modified with BIT_FIELD_REF");
3277 bool old_side_effects;
3280 bool new_side_effects;
3282 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3283 dead PHIs that take the address of something. But if the PHI
3284 result is dead, the fact that it takes the address of anything
3285 is irrelevant. Because we can not tell from here if a PHI result
3286 is dead, we just skip this check for PHIs altogether. This means
3287 we may be missing "valid" checks, but what can you do?
3288 This was PR19217. */
3292 old_invariant = TREE_INVARIANT (t);
3293 old_constant = TREE_CONSTANT (t);
3294 old_side_effects = TREE_SIDE_EFFECTS (t);
3296 recompute_tree_invariant_for_addr_expr (t);
3297 new_invariant = TREE_INVARIANT (t);
3298 new_side_effects = TREE_SIDE_EFFECTS (t);
3299 new_constant = TREE_CONSTANT (t);
3301 if (old_invariant != new_invariant)
3303 error ("invariant not recomputed when ADDR_EXPR changed");
3307 if (old_constant != new_constant)
3309 error ("constant not recomputed when ADDR_EXPR changed");
3312 if (old_side_effects != new_side_effects)
3314 error ("side effects not recomputed when ADDR_EXPR changed");
3318 /* Skip any references (they will be checked when we recurse down the
3319 tree) and ensure that any variable used as a prefix is marked
3321 for (x = TREE_OPERAND (t, 0);
3322 handled_component_p (x);
3323 x = TREE_OPERAND (x, 0))
3326 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3328 if (!TREE_ADDRESSABLE (x))
3330 error ("address taken, but ADDRESSABLE bit not set");
3337 x = COND_EXPR_COND (t);
3338 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3340 error ("non-boolean used in condition");
3343 if (!is_gimple_condexpr (x))
3345 error ("invalid conditional operand");
3352 case FIX_TRUNC_EXPR:
3354 case FIX_FLOOR_EXPR:
3355 case FIX_ROUND_EXPR:
3360 case NON_LVALUE_EXPR:
3361 case TRUTH_NOT_EXPR:
3362 CHECK_OP (0, "invalid operand to unary operator");
3369 case ARRAY_RANGE_REF:
3371 case VIEW_CONVERT_EXPR:
3372 /* We have a nest of references. Verify that each of the operands
3373 that determine where to reference is either a constant or a variable,
3374 verify that the base is valid, and then show we've already checked
3376 while (handled_component_p (t))
3378 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3379 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3380 else if (TREE_CODE (t) == ARRAY_REF
3381 || TREE_CODE (t) == ARRAY_RANGE_REF)
3383 CHECK_OP (1, "invalid array index");
3384 if (TREE_OPERAND (t, 2))
3385 CHECK_OP (2, "invalid array lower bound");
3386 if (TREE_OPERAND (t, 3))
3387 CHECK_OP (3, "invalid array stride");
3389 else if (TREE_CODE (t) == BIT_FIELD_REF)
3391 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3392 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3395 t = TREE_OPERAND (t, 0);
3398 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3400 error ("invalid reference prefix");
3412 case UNORDERED_EXPR:
3423 case TRUNC_DIV_EXPR:
3425 case FLOOR_DIV_EXPR:
3426 case ROUND_DIV_EXPR:
3427 case TRUNC_MOD_EXPR:
3429 case FLOOR_MOD_EXPR:
3430 case ROUND_MOD_EXPR:
3432 case EXACT_DIV_EXPR:
3442 CHECK_OP (0, "invalid operand to binary operator");
3443 CHECK_OP (1, "invalid operand to binary operator");
3447 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3460 /* Verify STMT, return true if STMT is not in GIMPLE form.
3461 TODO: Implement type checking. */
3464 verify_stmt (tree stmt, bool last_in_block)
3468 if (OMP_DIRECTIVE_P (stmt))
3470 /* OpenMP directives are validated by the FE and never operated
3471 on by the optimizers. Furthermore, OMP_FOR may contain
3472 non-gimple expressions when the main index variable has had
3473 its address taken. This does not affect the loop itself
3474 because the header of an OMP_FOR is merely used to determine
3475 how to setup the parallel iteration. */
3479 if (!is_gimple_stmt (stmt))
3481 error ("is not a valid GIMPLE statement");
3485 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3488 debug_generic_stmt (addr);
3492 /* If the statement is marked as part of an EH region, then it is
3493 expected that the statement could throw. Verify that when we
3494 have optimizations that simplify statements such that we prove
3495 that they cannot throw, that we update other data structures
3497 if (lookup_stmt_eh_region (stmt) >= 0)
3499 if (!tree_could_throw_p (stmt))
3501 error ("statement marked for throw, but doesn%'t");
3504 if (!last_in_block && tree_can_throw_internal (stmt))
3506 error ("statement marked for throw in middle of block");
3514 debug_generic_stmt (stmt);
3519 /* Return true when the T can be shared. */
3522 tree_node_can_be_shared (tree t)
3524 if (IS_TYPE_OR_DECL_P (t)
3525 || is_gimple_min_invariant (t)
3526 || TREE_CODE (t) == SSA_NAME
3527 || t == error_mark_node
3528 || TREE_CODE (t) == IDENTIFIER_NODE)
3531 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3534 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3535 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3536 || TREE_CODE (t) == COMPONENT_REF
3537 || TREE_CODE (t) == REALPART_EXPR
3538 || TREE_CODE (t) == IMAGPART_EXPR)
3539 t = TREE_OPERAND (t, 0);
3548 /* Called via walk_trees. Verify tree sharing. */
3551 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3553 htab_t htab = (htab_t) data;
3556 if (tree_node_can_be_shared (*tp))
3558 *walk_subtrees = false;
3562 slot = htab_find_slot (htab, *tp, INSERT);
3564 return (tree) *slot;
3571 /* Verify the GIMPLE statement chain. */
3577 block_stmt_iterator bsi;
3582 timevar_push (TV_TREE_STMT_VERIFY);
3583 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3590 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3592 int phi_num_args = PHI_NUM_ARGS (phi);
3594 if (bb_for_stmt (phi) != bb)
3596 error ("bb_for_stmt (phi) is set to a wrong basic block");
3600 for (i = 0; i < phi_num_args; i++)
3602 tree t = PHI_ARG_DEF (phi, i);
3605 /* Addressable variables do have SSA_NAMEs but they
3606 are not considered gimple values. */
3607 if (TREE_CODE (t) != SSA_NAME
3608 && TREE_CODE (t) != FUNCTION_DECL
3609 && !is_gimple_val (t))
3611 error ("PHI def is not a GIMPLE value");
3612 debug_generic_stmt (phi);
3613 debug_generic_stmt (t);
3617 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3620 debug_generic_stmt (addr);
3624 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3627 error ("incorrect sharing of tree nodes");
3628 debug_generic_stmt (phi);
3629 debug_generic_stmt (addr);
3635 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3637 tree stmt = bsi_stmt (bsi);
3639 if (bb_for_stmt (stmt) != bb)
3641 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3646 err |= verify_stmt (stmt, bsi_end_p (bsi));
3647 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3650 error ("incorrect sharing of tree nodes");
3651 debug_generic_stmt (stmt);
3652 debug_generic_stmt (addr);
3659 internal_error ("verify_stmts failed");
3662 timevar_pop (TV_TREE_STMT_VERIFY);
3666 /* Verifies that the flow information is OK. */
3669 tree_verify_flow_info (void)
3673 block_stmt_iterator bsi;
3678 if (ENTRY_BLOCK_PTR->stmt_list)
3680 error ("ENTRY_BLOCK has a statement list associated with it");
3684 if (EXIT_BLOCK_PTR->stmt_list)
3686 error ("EXIT_BLOCK has a statement list associated with it");
3690 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3691 if (e->flags & EDGE_FALLTHRU)
3693 error ("fallthru to exit from bb %d", e->src->index);
3699 bool found_ctrl_stmt = false;
3703 /* Skip labels on the start of basic block. */
3704 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3706 tree prev_stmt = stmt;
3708 stmt = bsi_stmt (bsi);
3710 if (TREE_CODE (stmt) != LABEL_EXPR)
3713 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3715 error ("nonlocal label ");
3716 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3717 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3722 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3725 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3726 fprintf (stderr, " to block does not match in bb %d",
3731 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3732 != current_function_decl)
3735 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3736 fprintf (stderr, " has incorrect context in bb %d",
3742 /* Verify that body of basic block BB is free of control flow. */
3743 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3745 tree stmt = bsi_stmt (bsi);
3747 if (found_ctrl_stmt)
3749 error ("control flow in the middle of basic block %d",
3754 if (stmt_ends_bb_p (stmt))
3755 found_ctrl_stmt = true;
3757 if (TREE_CODE (stmt) == LABEL_EXPR)
3760 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3761 fprintf (stderr, " in the middle of basic block %d", bb->index);
3766 bsi = bsi_last (bb);
3767 if (bsi_end_p (bsi))
3770 stmt = bsi_stmt (bsi);
3772 err |= verify_eh_edges (stmt);
3774 if (is_ctrl_stmt (stmt))
3776 FOR_EACH_EDGE (e, ei, bb->succs)
3777 if (e->flags & EDGE_FALLTHRU)
3779 error ("fallthru edge after a control statement in bb %d",
3785 if (TREE_CODE (stmt) != COND_EXPR)
3787 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3788 after anything else but if statement. */
3789 FOR_EACH_EDGE (e, ei, bb->succs)
3790 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3792 error ("true/false edge after a non-COND_EXPR in bb %d",
3798 switch (TREE_CODE (stmt))
3804 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3805 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3807 error ("structured COND_EXPR at the end of bb %d", bb->index);
3811 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3813 if (!true_edge || !false_edge
3814 || !(true_edge->flags & EDGE_TRUE_VALUE)
3815 || !(false_edge->flags & EDGE_FALSE_VALUE)
3816 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3817 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3818 || EDGE_COUNT (bb->succs) >= 3)
3820 error ("wrong outgoing edge flags at end of bb %d",
3825 if (!has_label_p (true_edge->dest,
3826 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3828 error ("%<then%> label does not match edge at end of bb %d",
3833 if (!has_label_p (false_edge->dest,
3834 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3836 error ("%<else%> label does not match edge at end of bb %d",
3844 if (simple_goto_p (stmt))
3846 error ("explicit goto at end of bb %d", bb->index);
3851 /* FIXME. We should double check that the labels in the
3852 destination blocks have their address taken. */
3853 FOR_EACH_EDGE (e, ei, bb->succs)
3854 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3855 | EDGE_FALSE_VALUE))
3856 || !(e->flags & EDGE_ABNORMAL))
3858 error ("wrong outgoing edge flags at end of bb %d",
3866 if (!single_succ_p (bb)
3867 || (single_succ_edge (bb)->flags
3868 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3869 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3871 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3874 if (single_succ (bb) != EXIT_BLOCK_PTR)
3876 error ("return edge does not point to exit in bb %d",
3889 vec = SWITCH_LABELS (stmt);
3890 n = TREE_VEC_LENGTH (vec);
3892 /* Mark all the destination basic blocks. */
3893 for (i = 0; i < n; ++i)
3895 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3896 basic_block label_bb = label_to_block (lab);
3898 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3899 label_bb->aux = (void *)1;
3902 /* Verify that the case labels are sorted. */
3903 prev = TREE_VEC_ELT (vec, 0);
3904 for (i = 1; i < n - 1; ++i)
3906 tree c = TREE_VEC_ELT (vec, i);
3909 error ("found default case not at end of case vector");
3913 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3915 error ("case labels not sorted: ");
3916 print_generic_expr (stderr, prev, 0);
3917 fprintf (stderr," is greater than ");
3918 print_generic_expr (stderr, c, 0);
3919 fprintf (stderr," but comes before it.\n");
3924 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3926 error ("no default case found at end of case vector");
3930 FOR_EACH_EDGE (e, ei, bb->succs)
3934 error ("extra outgoing edge %d->%d",
3935 bb->index, e->dest->index);
3938 e->dest->aux = (void *)2;
3939 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3940 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3942 error ("wrong outgoing edge flags at end of bb %d",
3948 /* Check that we have all of them. */
3949 for (i = 0; i < n; ++i)
3951 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3952 basic_block label_bb = label_to_block (lab);
3954 if (label_bb->aux != (void *)2)
3956 error ("missing edge %i->%i",
3957 bb->index, label_bb->index);
3962 FOR_EACH_EDGE (e, ei, bb->succs)
3963 e->dest->aux = (void *)0;
3970 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3971 verify_dominators (CDI_DOMINATORS);
3977 /* Updates phi nodes after creating a forwarder block joined
3978 by edge FALLTHRU. */
3981 tree_make_forwarder_block (edge fallthru)
3985 basic_block dummy, bb;
3986 tree phi, new_phi, var;
3988 dummy = fallthru->src;
3989 bb = fallthru->dest;
3991 if (single_pred_p (bb))
3994 /* If we redirected a branch we must create new phi nodes at the
3996 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3998 var = PHI_RESULT (phi);
3999 new_phi = create_phi_node (var, bb);
4000 SSA_NAME_DEF_STMT (var) = new_phi;
4001 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
4002 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
4005 /* Ensure that the PHI node chain is in the same order. */
4006 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
4008 /* Add the arguments we have stored on edges. */
4009 FOR_EACH_EDGE (e, ei, bb->preds)
4014 flush_pending_stmts (e);
4019 /* Return a non-special label in the head of basic block BLOCK.
4020 Create one if it doesn't exist. */
4023 tree_block_label (basic_block bb)
4025 block_stmt_iterator i, s = bsi_start (bb);
4029 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4031 stmt = bsi_stmt (i);
4032 if (TREE_CODE (stmt) != LABEL_EXPR)
4034 label = LABEL_EXPR_LABEL (stmt);
4035 if (!DECL_NONLOCAL (label))
4038 bsi_move_before (&i, &s);
4043 label = create_artificial_label ();
4044 stmt = build1 (LABEL_EXPR, void_type_node, label);
4045 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4050 /* Attempt to perform edge redirection by replacing a possibly complex
4051 jump instruction by a goto or by removing the jump completely.
4052 This can apply only if all edges now point to the same block. The
4053 parameters and return values are equivalent to
4054 redirect_edge_and_branch. */
4057 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4059 basic_block src = e->src;
4060 block_stmt_iterator b;
4063 /* We can replace or remove a complex jump only when we have exactly
4065 if (EDGE_COUNT (src->succs) != 2
4066 /* Verify that all targets will be TARGET. Specifically, the
4067 edge that is not E must also go to TARGET. */
4068 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4074 stmt = bsi_stmt (b);
4076 if (TREE_CODE (stmt) == COND_EXPR
4077 || TREE_CODE (stmt) == SWITCH_EXPR)
4079 bsi_remove (&b, true);
4080 e = ssa_redirect_edge (e, target);
4081 e->flags = EDGE_FALLTHRU;
4089 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4090 edge representing the redirected branch. */
4093 tree_redirect_edge_and_branch (edge e, basic_block dest)
4095 basic_block bb = e->src;
4096 block_stmt_iterator bsi;
4100 if (e->flags & EDGE_ABNORMAL)
4103 if (e->src != ENTRY_BLOCK_PTR
4104 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4107 if (e->dest == dest)
4110 label = tree_block_label (dest);
4112 bsi = bsi_last (bb);
4113 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4115 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4118 stmt = (e->flags & EDGE_TRUE_VALUE
4119 ? COND_EXPR_THEN (stmt)
4120 : COND_EXPR_ELSE (stmt));
4121 GOTO_DESTINATION (stmt) = label;
4125 /* No non-abnormal edges should lead from a non-simple goto, and
4126 simple ones should be represented implicitly. */
4131 tree cases = get_cases_for_edge (e, stmt);
4133 /* If we have a list of cases associated with E, then use it
4134 as it's a lot faster than walking the entire case vector. */
4137 edge e2 = find_edge (e->src, dest);
4144 CASE_LABEL (cases) = label;
4145 cases = TREE_CHAIN (cases);
4148 /* If there was already an edge in the CFG, then we need
4149 to move all the cases associated with E to E2. */
4152 tree cases2 = get_cases_for_edge (e2, stmt);
4154 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4155 TREE_CHAIN (cases2) = first;
4160 tree vec = SWITCH_LABELS (stmt);
4161 size_t i, n = TREE_VEC_LENGTH (vec);
4163 for (i = 0; i < n; i++)
4165 tree elt = TREE_VEC_ELT (vec, i);
4167 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4168 CASE_LABEL (elt) = label;
4176 bsi_remove (&bsi, true);
4177 e->flags |= EDGE_FALLTHRU;
4181 /* Otherwise it must be a fallthru edge, and we don't need to
4182 do anything besides redirecting it. */
4183 gcc_assert (e->flags & EDGE_FALLTHRU);
4187 /* Update/insert PHI nodes as necessary. */
4189 /* Now update the edges in the CFG. */
4190 e = ssa_redirect_edge (e, dest);
4196 /* Simple wrapper, as we can always redirect fallthru edges. */
4199 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4201 e = tree_redirect_edge_and_branch (e, dest);
4208 /* Splits basic block BB after statement STMT (but at least after the
4209 labels). If STMT is NULL, BB is split just after the labels. */
4212 tree_split_block (basic_block bb, void *stmt)
4214 block_stmt_iterator bsi;
4215 tree_stmt_iterator tsi_tgt;
4221 new_bb = create_empty_bb (bb);
4223 /* Redirect the outgoing edges. */
4224 new_bb->succs = bb->succs;
4226 FOR_EACH_EDGE (e, ei, new_bb->succs)
4229 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4232 /* Move everything from BSI to the new basic block. */
4233 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4235 act = bsi_stmt (bsi);
4236 if (TREE_CODE (act) == LABEL_EXPR)
4249 if (bsi_end_p (bsi))
4252 /* Split the statement list - avoid re-creating new containers as this
4253 brings ugly quadratic memory consumption in the inliner.
4254 (We are still quadratic since we need to update stmt BB pointers,
4256 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4257 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4258 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4259 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4265 /* Moves basic block BB after block AFTER. */
4268 tree_move_block_after (basic_block bb, basic_block after)
4270 if (bb->prev_bb == after)
4274 link_block (bb, after);
4280 /* Return true if basic_block can be duplicated. */
4283 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4289 /* Create a duplicate of the basic block BB. NOTE: This does not
4290 preserve SSA form. */
4293 tree_duplicate_bb (basic_block bb)
4296 block_stmt_iterator bsi, bsi_tgt;
4299 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4301 /* Copy the PHI nodes. We ignore PHI node arguments here because
4302 the incoming edges have not been setup yet. */
4303 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4305 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4306 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4309 /* Keep the chain of PHI nodes in the same order so that they can be
4310 updated by ssa_redirect_edge. */
4311 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4313 bsi_tgt = bsi_start (new_bb);
4314 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4316 def_operand_p def_p;
4317 ssa_op_iter op_iter;
4321 stmt = bsi_stmt (bsi);
4322 if (TREE_CODE (stmt) == LABEL_EXPR)
4325 /* Create a new copy of STMT and duplicate STMT's virtual
4327 copy = unshare_expr (stmt);
4328 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4329 copy_virtual_operands (copy, stmt);
4330 region = lookup_stmt_eh_region (stmt);
4332 add_stmt_to_eh_region (copy, region);
4334 /* Create new names for all the definitions created by COPY and
4335 add replacement mappings for each new name. */
4336 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4337 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4344 /* Basic block BB_COPY was created by code duplication. Add phi node
4345 arguments for edges going out of BB_COPY. The blocks that were
4346 duplicated have BB_DUPLICATED set. */
4349 add_phi_args_after_copy_bb (basic_block bb_copy)
4351 basic_block bb, dest;
4354 tree phi, phi_copy, phi_next, def;
4356 bb = get_bb_original (bb_copy);
4358 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4360 if (!phi_nodes (e_copy->dest))
4363 if (e_copy->dest->flags & BB_DUPLICATED)
4364 dest = get_bb_original (e_copy->dest);
4366 dest = e_copy->dest;
4368 e = find_edge (bb, dest);
4371 /* During loop unrolling the target of the latch edge is copied.
4372 In this case we are not looking for edge to dest, but to
4373 duplicated block whose original was dest. */
4374 FOR_EACH_EDGE (e, ei, bb->succs)
4375 if ((e->dest->flags & BB_DUPLICATED)
4376 && get_bb_original (e->dest) == dest)
4379 gcc_assert (e != NULL);
4382 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4384 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4386 phi_next = PHI_CHAIN (phi);
4387 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4388 add_phi_arg (phi_copy, def, e_copy);
4393 /* Blocks in REGION_COPY array of length N_REGION were created by
4394 duplication of basic blocks. Add phi node arguments for edges
4395 going from these blocks. */
4398 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4402 for (i = 0; i < n_region; i++)
4403 region_copy[i]->flags |= BB_DUPLICATED;
4405 for (i = 0; i < n_region; i++)
4406 add_phi_args_after_copy_bb (region_copy[i]);
4408 for (i = 0; i < n_region; i++)
4409 region_copy[i]->flags &= ~BB_DUPLICATED;
4412 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4413 important exit edge EXIT. By important we mean that no SSA name defined
4414 inside region is live over the other exit edges of the region. All entry
4415 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4416 to the duplicate of the region. SSA form, dominance and loop information
4417 is updated. The new basic blocks are stored to REGION_COPY in the same
4418 order as they had in REGION, provided that REGION_COPY is not NULL.
4419 The function returns false if it is unable to copy the region,
4423 tree_duplicate_sese_region (edge entry, edge exit,
4424 basic_block *region, unsigned n_region,
4425 basic_block *region_copy)
4428 bool free_region_copy = false, copying_header = false;
4429 struct loop *loop = entry->dest->loop_father;
4433 int total_freq = 0, entry_freq = 0;
4434 gcov_type total_count = 0, entry_count = 0;
4436 if (!can_copy_bbs_p (region, n_region))
4439 /* Some sanity checking. Note that we do not check for all possible
4440 missuses of the functions. I.e. if you ask to copy something weird,
4441 it will work, but the state of structures probably will not be
4443 for (i = 0; i < n_region; i++)
4445 /* We do not handle subloops, i.e. all the blocks must belong to the
4447 if (region[i]->loop_father != loop)
4450 if (region[i] != entry->dest
4451 && region[i] == loop->header)
4457 /* In case the function is used for loop header copying (which is the primary
4458 use), ensure that EXIT and its copy will be new latch and entry edges. */
4459 if (loop->header == entry->dest)
4461 copying_header = true;
4462 loop->copy = loop->outer;
4464 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4467 for (i = 0; i < n_region; i++)
4468 if (region[i] != exit->src
4469 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4475 region_copy = XNEWVEC (basic_block, n_region);
4476 free_region_copy = true;
4479 gcc_assert (!need_ssa_update_p ());
4481 /* Record blocks outside the region that are dominated by something
4483 doms = XNEWVEC (basic_block, n_basic_blocks);
4484 initialize_original_copy_tables ();
4486 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4488 if (entry->dest->count)
4490 total_count = entry->dest->count;
4491 entry_count = entry->count;
4492 /* Fix up corner cases, to avoid division by zero or creation of negative
4494 if (entry_count > total_count)
4495 entry_count = total_count;
4499 total_freq = entry->dest->frequency;
4500 entry_freq = EDGE_FREQUENCY (entry);
4501 /* Fix up corner cases, to avoid division by zero or creation of negative
4503 if (total_freq == 0)
4505 else if (entry_freq > total_freq)
4506 entry_freq = total_freq;
4509 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4510 split_edge_bb_loc (entry));
4513 scale_bbs_frequencies_gcov_type (region, n_region,
4514 total_count - entry_count,
4516 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4521 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4523 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4528 loop->header = exit->dest;
4529 loop->latch = exit->src;
4532 /* Redirect the entry and add the phi node arguments. */
4533 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4534 gcc_assert (redirected != NULL);
4535 flush_pending_stmts (entry);
4537 /* Concerning updating of dominators: We must recount dominators
4538 for entry block and its copy. Anything that is outside of the
4539 region, but was dominated by something inside needs recounting as
4541 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4542 doms[n_doms++] = get_bb_original (entry->dest);
4543 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4546 /* Add the other PHI node arguments. */
4547 add_phi_args_after_copy (region_copy, n_region);
4549 /* Update the SSA web. */
4550 update_ssa (TODO_update_ssa);
4552 if (free_region_copy)
4555 free_original_copy_tables ();
4560 DEF_VEC_P(basic_block);
4561 DEF_VEC_ALLOC_P(basic_block,heap);
4564 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4565 adding blocks when the dominator traversal reaches EXIT. This
4566 function silently assumes that ENTRY strictly dominates EXIT. */
4569 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4570 VEC(basic_block,heap) **bbs_p)
4574 for (son = first_dom_son (CDI_DOMINATORS, entry);
4576 son = next_dom_son (CDI_DOMINATORS, son))
4578 VEC_safe_push (basic_block, heap, *bbs_p, son);
4580 gather_blocks_in_sese_region (son, exit, bbs_p);
4590 bitmap vars_to_remove;
4591 htab_t new_label_map;
4595 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4596 contained in *TP and change the DECL_CONTEXT of every local
4597 variable referenced in *TP. */
4600 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4602 struct move_stmt_d *p = (struct move_stmt_d *) data;
4605 if (p->block && IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t))))
4606 TREE_BLOCK (t) = p->block;
4608 if (OMP_DIRECTIVE_P (t)
4609 && TREE_CODE (t) != OMP_RETURN
4610 && TREE_CODE (t) != OMP_CONTINUE)
4612 /* Do not remap variables inside OMP directives. Variables
4613 referenced in clauses and directive header belong to the
4614 parent function and should not be moved into the child
4616 bool save_remap_decls_p = p->remap_decls_p;
4617 p->remap_decls_p = false;
4620 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4622 p->remap_decls_p = save_remap_decls_p;
4624 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4626 if (TREE_CODE (t) == LABEL_DECL)
4628 if (p->new_label_map)
4630 struct tree_map in, *out;
4632 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4637 DECL_CONTEXT (t) = p->to_context;
4639 else if (p->remap_decls_p)
4641 DECL_CONTEXT (t) = p->to_context;
4643 if (TREE_CODE (t) == VAR_DECL)
4645 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4646 f->unexpanded_var_list
4647 = tree_cons (0, t, f->unexpanded_var_list);
4649 /* Mark T to be removed from the original function,
4650 otherwise it will be given a DECL_RTL when the
4651 original function is expanded. */
4652 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4656 else if (TYPE_P (t))
4663 /* Move basic block BB from function CFUN to function DEST_FN. The
4664 block is moved out of the original linked list and placed after
4665 block AFTER in the new list. Also, the block is removed from the
4666 original array of blocks and placed in DEST_FN's array of blocks.
4667 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4668 updated to reflect the moved edges.
4670 On exit, local variables that need to be removed from
4671 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4674 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4675 basic_block after, bool update_edge_count_p,
4676 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4678 struct control_flow_graph *cfg;
4681 block_stmt_iterator si;
4682 struct move_stmt_d d;
4683 unsigned old_len, new_len;
4686 /* Link BB to the new linked list. */
4687 move_block_after (bb, after);
4689 /* Update the edge count in the corresponding flowgraphs. */
4690 if (update_edge_count_p)
4691 FOR_EACH_EDGE (e, ei, bb->succs)
4693 cfun->cfg->x_n_edges--;
4694 dest_cfun->cfg->x_n_edges++;
4697 /* Remove BB from the original basic block array. */
4698 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4699 cfun->cfg->x_n_basic_blocks--;
4701 /* Grow DEST_CFUN's basic block array if needed. */
4702 cfg = dest_cfun->cfg;
4703 cfg->x_n_basic_blocks++;
4704 if (bb->index > cfg->x_last_basic_block)
4705 cfg->x_last_basic_block = bb->index;
4707 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4708 if ((unsigned) cfg->x_last_basic_block >= old_len)
4710 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4711 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4712 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4713 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4716 VEC_replace (basic_block, cfg->x_basic_block_info,
4717 cfg->x_last_basic_block, bb);
4719 /* The statements in BB need to be associated with a new TREE_BLOCK.
4720 Labels need to be associated with a new label-to-block map. */
4721 memset (&d, 0, sizeof (d));
4722 d.vars_to_remove = vars_to_remove;
4724 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4726 tree stmt = bsi_stmt (si);
4729 d.from_context = cfun->decl;
4730 d.to_context = dest_cfun->decl;
4731 d.remap_decls_p = true;
4732 d.new_label_map = new_label_map;
4733 if (TREE_BLOCK (stmt))
4734 d.block = DECL_INITIAL (dest_cfun->decl);
4736 walk_tree (&stmt, move_stmt_r, &d, NULL);
4738 if (TREE_CODE (stmt) == LABEL_EXPR)
4740 tree label = LABEL_EXPR_LABEL (stmt);
4741 int uid = LABEL_DECL_UID (label);
4743 gcc_assert (uid > -1);
4745 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4746 if (old_len <= (unsigned) uid)
4748 new_len = 3 * uid / 2;
4749 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4751 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4752 memset (&addr[old_len], 0,
4753 sizeof (basic_block) * (new_len - old_len));
4756 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4757 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4759 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4761 if (uid >= dest_cfun->last_label_uid)
4762 dest_cfun->last_label_uid = uid + 1;
4764 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4765 TREE_OPERAND (stmt, 0) =
4766 build_int_cst (NULL_TREE,
4767 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4770 region = lookup_stmt_eh_region (stmt);
4773 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4774 remove_stmt_from_eh_region (stmt);
4779 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4780 the outermost EH region. Use REGION as the incoming base EH region. */
4783 find_outermost_region_in_block (struct function *src_cfun,
4784 basic_block bb, int region)
4786 block_stmt_iterator si;
4788 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4790 tree stmt = bsi_stmt (si);
4793 if (TREE_CODE (stmt) == RESX_EXPR)
4794 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4796 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4797 if (stmt_region > 0)
4800 region = stmt_region;
4801 else if (stmt_region != region)
4803 region = eh_region_outermost (src_cfun, stmt_region, region);
4804 gcc_assert (region != -1);
4813 new_label_mapper (tree decl, void *data)
4815 htab_t hash = (htab_t) data;
4819 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4821 m = xmalloc (sizeof (struct tree_map));
4822 m->hash = DECL_UID (decl);
4824 m->to = create_artificial_label ();
4825 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4827 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4828 gcc_assert (*slot == NULL);
4835 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4836 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4837 single basic block in the original CFG and the new basic block is
4838 returned. DEST_CFUN must not have a CFG yet.
4840 Note that the region need not be a pure SESE region. Blocks inside
4841 the region may contain calls to abort/exit. The only restriction
4842 is that ENTRY_BB should be the only entry point and it must
4845 All local variables referenced in the region are assumed to be in
4846 the corresponding BLOCK_VARS and unexpanded variable lists
4847 associated with DEST_CFUN. */
4850 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4851 basic_block exit_bb)
4853 VEC(basic_block,heap) *bbs;
4854 basic_block after, bb, *entry_pred, *exit_succ;
4855 struct function *saved_cfun;
4856 int *entry_flag, *exit_flag, eh_offset;
4857 unsigned i, num_entry_edges, num_exit_edges;
4860 bitmap vars_to_remove;
4861 htab_t new_label_map;
4865 /* Collect all the blocks in the region. Manually add ENTRY_BB
4866 because it won't be added by dfs_enumerate_from. */
4867 calculate_dominance_info (CDI_DOMINATORS);
4869 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4871 gcc_assert (entry_bb != exit_bb
4873 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4876 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4877 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4879 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4880 the predecessor edges to ENTRY_BB and the successor edges to
4881 EXIT_BB so that we can re-attach them to the new basic block that
4882 will replace the region. */
4883 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4884 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4885 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4887 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4889 entry_flag[i] = e->flags;
4890 entry_pred[i++] = e->src;
4896 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4897 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4898 sizeof (basic_block));
4899 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4901 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4903 exit_flag[i] = e->flags;
4904 exit_succ[i++] = e->dest;
4915 /* Switch context to the child function to initialize DEST_FN's CFG. */
4916 gcc_assert (dest_cfun->cfg == NULL);
4919 init_empty_tree_cfg ();
4921 /* Initialize EH information for the new function. */
4923 new_label_map = NULL;
4928 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4929 region = find_outermost_region_in_block (saved_cfun, bb, region);
4931 init_eh_for_function ();
4934 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4935 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4936 new_label_map, region, 0);
4942 /* Move blocks from BBS into DEST_CFUN. */
4943 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4944 after = dest_cfun->cfg->x_entry_block_ptr;
4945 vars_to_remove = BITMAP_ALLOC (NULL);
4946 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4948 /* No need to update edge counts on the last block. It has
4949 already been updated earlier when we detached the region from
4950 the original CFG. */
4951 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4952 new_label_map, eh_offset);
4957 htab_delete (new_label_map);
4959 /* Remove the variables marked in VARS_TO_REMOVE from
4960 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4961 DECL_RTL in the context of CFUN. */
4962 if (!bitmap_empty_p (vars_to_remove))
4966 for (p = &cfun->unexpanded_var_list; *p; )
4968 tree var = TREE_VALUE (*p);
4969 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4971 *p = TREE_CHAIN (*p);
4975 p = &TREE_CHAIN (*p);
4979 BITMAP_FREE (vars_to_remove);
4981 /* Rewire the entry and exit blocks. The successor to the entry
4982 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4983 the child function. Similarly, the predecessor of DEST_FN's
4984 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4985 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4986 various CFG manipulation function get to the right CFG.
4988 FIXME, this is silly. The CFG ought to become a parameter to
4991 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4993 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4996 /* Back in the original function, the SESE region has disappeared,
4997 create a new basic block in its place. */
4998 bb = create_empty_bb (entry_pred[0]);
4999 for (i = 0; i < num_entry_edges; i++)
5000 make_edge (entry_pred[i], bb, entry_flag[i]);
5002 for (i = 0; i < num_exit_edges; i++)
5003 make_edge (bb, exit_succ[i], exit_flag[i]);
5012 free_dominance_info (CDI_DOMINATORS);
5013 free_dominance_info (CDI_POST_DOMINATORS);
5014 VEC_free (basic_block, heap, bbs);
5020 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5023 dump_function_to_file (tree fn, FILE *file, int flags)
5025 tree arg, vars, var;
5026 bool ignore_topmost_bind = false, any_var = false;
5029 struct function *saved_cfun;
5031 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5033 arg = DECL_ARGUMENTS (fn);
5036 print_generic_expr (file, arg, dump_flags);
5037 if (TREE_CHAIN (arg))
5038 fprintf (file, ", ");
5039 arg = TREE_CHAIN (arg);
5041 fprintf (file, ")\n");
5043 if (flags & TDF_DETAILS)
5044 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5045 if (flags & TDF_RAW)
5047 dump_node (fn, TDF_SLIM | flags, file);
5051 /* Switch CFUN to point to FN. */
5053 cfun = DECL_STRUCT_FUNCTION (fn);
5055 /* When GIMPLE is lowered, the variables are no longer available in
5056 BIND_EXPRs, so display them separately. */
5057 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5059 ignore_topmost_bind = true;
5061 fprintf (file, "{\n");
5062 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5064 var = TREE_VALUE (vars);
5066 print_generic_decl (file, var, flags);
5067 fprintf (file, "\n");
5073 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5075 /* Make a CFG based dump. */
5076 check_bb_profile (ENTRY_BLOCK_PTR, file);
5077 if (!ignore_topmost_bind)
5078 fprintf (file, "{\n");
5080 if (any_var && n_basic_blocks)
5081 fprintf (file, "\n");
5084 dump_generic_bb (file, bb, 2, flags);
5086 fprintf (file, "}\n");
5087 check_bb_profile (EXIT_BLOCK_PTR, file);
5093 /* Make a tree based dump. */
5094 chain = DECL_SAVED_TREE (fn);
5096 if (chain && TREE_CODE (chain) == BIND_EXPR)
5098 if (ignore_topmost_bind)
5100 chain = BIND_EXPR_BODY (chain);
5108 if (!ignore_topmost_bind)
5109 fprintf (file, "{\n");
5114 fprintf (file, "\n");
5116 print_generic_stmt_indented (file, chain, flags, indent);
5117 if (ignore_topmost_bind)
5118 fprintf (file, "}\n");
5121 fprintf (file, "\n\n");
5128 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5131 debug_function (tree fn, int flags)
5133 dump_function_to_file (fn, stderr, flags);
5137 /* Pretty print of the loops intermediate representation. */
5138 static void print_loop (FILE *, struct loop *, int);
5139 static void print_pred_bbs (FILE *, basic_block bb);
5140 static void print_succ_bbs (FILE *, basic_block bb);
5143 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5146 print_pred_bbs (FILE *file, basic_block bb)
5151 FOR_EACH_EDGE (e, ei, bb->preds)
5152 fprintf (file, "bb_%d ", e->src->index);
5156 /* Print on FILE the indexes for the successors of basic_block BB. */
5159 print_succ_bbs (FILE *file, basic_block bb)
5164 FOR_EACH_EDGE (e, ei, bb->succs)
5165 fprintf (file, "bb_%d ", e->dest->index);
5169 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5172 print_loop (FILE *file, struct loop *loop, int indent)
5180 s_indent = (char *) alloca ((size_t) indent + 1);
5181 memset ((void *) s_indent, ' ', (size_t) indent);
5182 s_indent[indent] = '\0';
5184 /* Print the loop's header. */
5185 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5187 /* Print the loop's body. */
5188 fprintf (file, "%s{\n", s_indent);
5190 if (bb->loop_father == loop)
5192 /* Print the basic_block's header. */
5193 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5194 print_pred_bbs (file, bb);
5195 fprintf (file, "}, succs = {");
5196 print_succ_bbs (file, bb);
5197 fprintf (file, "})\n");
5199 /* Print the basic_block's body. */
5200 fprintf (file, "%s {\n", s_indent);
5201 tree_dump_bb (bb, file, indent + 4);
5202 fprintf (file, "%s }\n", s_indent);
5205 print_loop (file, loop->inner, indent + 2);
5206 fprintf (file, "%s}\n", s_indent);
5207 print_loop (file, loop->next, indent);
5211 /* Follow a CFG edge from the entry point of the program, and on entry
5212 of a loop, pretty print the loop structure on FILE. */
5215 print_loop_ir (FILE *file)
5219 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5220 if (bb && bb->loop_father)
5221 print_loop (file, bb->loop_father, 0);
5225 /* Debugging loops structure at tree level. */
5228 debug_loop_ir (void)
5230 print_loop_ir (stderr);
5234 /* Return true if BB ends with a call, possibly followed by some
5235 instructions that must stay with the call. Return false,
5239 tree_block_ends_with_call_p (basic_block bb)
5241 block_stmt_iterator bsi = bsi_last (bb);
5242 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5246 /* Return true if BB ends with a conditional branch. Return false,
5250 tree_block_ends_with_condjump_p (basic_block bb)
5252 tree stmt = last_stmt (bb);
5253 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5257 /* Return true if we need to add fake edge to exit at statement T.
5258 Helper function for tree_flow_call_edges_add. */
5261 need_fake_edge_p (tree t)
5265 /* NORETURN and LONGJMP calls already have an edge to exit.
5266 CONST and PURE calls do not need one.
5267 We don't currently check for CONST and PURE here, although
5268 it would be a good idea, because those attributes are
5269 figured out from the RTL in mark_constant_function, and
5270 the counter incrementation code from -fprofile-arcs
5271 leads to different results from -fbranch-probabilities. */
5272 call = get_call_expr_in (t);
5274 && !(call_expr_flags (call) & ECF_NORETURN))
5277 if (TREE_CODE (t) == ASM_EXPR
5278 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5285 /* Add fake edges to the function exit for any non constant and non
5286 noreturn calls, volatile inline assembly in the bitmap of blocks
5287 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5288 the number of blocks that were split.
5290 The goal is to expose cases in which entering a basic block does
5291 not imply that all subsequent instructions must be executed. */
5294 tree_flow_call_edges_add (sbitmap blocks)
5297 int blocks_split = 0;
5298 int last_bb = last_basic_block;
5299 bool check_last_block = false;
5301 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5305 check_last_block = true;
5307 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5309 /* In the last basic block, before epilogue generation, there will be
5310 a fallthru edge to EXIT. Special care is required if the last insn
5311 of the last basic block is a call because make_edge folds duplicate
5312 edges, which would result in the fallthru edge also being marked
5313 fake, which would result in the fallthru edge being removed by
5314 remove_fake_edges, which would result in an invalid CFG.
5316 Moreover, we can't elide the outgoing fake edge, since the block
5317 profiler needs to take this into account in order to solve the minimal
5318 spanning tree in the case that the call doesn't return.
5320 Handle this by adding a dummy instruction in a new last basic block. */
5321 if (check_last_block)
5323 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5324 block_stmt_iterator bsi = bsi_last (bb);
5326 if (!bsi_end_p (bsi))
5329 if (t && need_fake_edge_p (t))
5333 e = find_edge (bb, EXIT_BLOCK_PTR);
5336 bsi_insert_on_edge (e, build_empty_stmt ());
5337 bsi_commit_edge_inserts ();
5342 /* Now add fake edges to the function exit for any non constant
5343 calls since there is no way that we can determine if they will
5345 for (i = 0; i < last_bb; i++)
5347 basic_block bb = BASIC_BLOCK (i);
5348 block_stmt_iterator bsi;
5349 tree stmt, last_stmt;
5354 if (blocks && !TEST_BIT (blocks, i))
5357 bsi = bsi_last (bb);
5358 if (!bsi_end_p (bsi))
5360 last_stmt = bsi_stmt (bsi);
5363 stmt = bsi_stmt (bsi);
5364 if (need_fake_edge_p (stmt))
5367 /* The handling above of the final block before the
5368 epilogue should be enough to verify that there is
5369 no edge to the exit block in CFG already.
5370 Calling make_edge in such case would cause us to
5371 mark that edge as fake and remove it later. */
5372 #ifdef ENABLE_CHECKING
5373 if (stmt == last_stmt)
5375 e = find_edge (bb, EXIT_BLOCK_PTR);
5376 gcc_assert (e == NULL);
5380 /* Note that the following may create a new basic block
5381 and renumber the existing basic blocks. */
5382 if (stmt != last_stmt)
5384 e = split_block (bb, stmt);
5388 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5392 while (!bsi_end_p (bsi));
5397 verify_flow_info ();
5399 return blocks_split;
5402 /* Purge dead abnormal call edges from basic block BB. */
5405 tree_purge_dead_abnormal_call_edges (basic_block bb)
5407 bool changed = tree_purge_dead_eh_edges (bb);
5409 if (current_function_has_nonlocal_label)
5411 tree stmt = last_stmt (bb);
5415 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5416 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5418 if (e->flags & EDGE_ABNORMAL)
5427 /* See tree_purge_dead_eh_edges below. */
5429 free_dominance_info (CDI_DOMINATORS);
5435 /* Purge dead EH edges from basic block BB. */
5438 tree_purge_dead_eh_edges (basic_block bb)
5440 bool changed = false;
5443 tree stmt = last_stmt (bb);
5445 if (stmt && tree_can_throw_internal (stmt))
5448 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5450 if (e->flags & EDGE_EH)
5459 /* Removal of dead EH edges might change dominators of not
5460 just immediate successors. E.g. when bb1 is changed so that
5461 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5462 eh edges purged by this function in:
5474 idom(bb5) must be recomputed. For now just free the dominance
5477 free_dominance_info (CDI_DOMINATORS);
5483 tree_purge_all_dead_eh_edges (bitmap blocks)
5485 bool changed = false;
5489 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5491 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5497 /* This function is called whenever a new edge is created or
5501 tree_execute_on_growing_pred (edge e)
5503 basic_block bb = e->dest;
5506 reserve_phi_args_for_new_edge (bb);
5509 /* This function is called immediately before edge E is removed from
5510 the edge vector E->dest->preds. */
5513 tree_execute_on_shrinking_pred (edge e)
5515 if (phi_nodes (e->dest))
5516 remove_phi_args (e);
5519 /*---------------------------------------------------------------------------
5520 Helper functions for Loop versioning
5521 ---------------------------------------------------------------------------*/
5523 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5524 of 'first'. Both of them are dominated by 'new_head' basic block. When
5525 'new_head' was created by 'second's incoming edge it received phi arguments
5526 on the edge by split_edge(). Later, additional edge 'e' was created to
5527 connect 'new_head' and 'first'. Now this routine adds phi args on this
5528 additional edge 'e' that new_head to second edge received as part of edge
5533 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5534 basic_block new_head, edge e)
5537 edge e2 = find_edge (new_head, second);
5539 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5540 edge, we should always have an edge from NEW_HEAD to SECOND. */
5541 gcc_assert (e2 != NULL);
5543 /* Browse all 'second' basic block phi nodes and add phi args to
5544 edge 'e' for 'first' head. PHI args are always in correct order. */
5546 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5548 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5550 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5551 add_phi_arg (phi1, def, e);
5555 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5556 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5557 the destination of the ELSE part. */
5559 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5560 basic_block cond_bb, void *cond_e)
5562 block_stmt_iterator bsi;
5563 tree goto1 = NULL_TREE;
5564 tree goto2 = NULL_TREE;
5565 tree new_cond_expr = NULL_TREE;
5566 tree cond_expr = (tree) cond_e;
5569 /* Build new conditional expr */
5570 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5571 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5572 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5574 /* Add new cond in cond_bb. */
5575 bsi = bsi_start (cond_bb);
5576 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5577 /* Adjust edges appropriately to connect new head with first head
5578 as well as second head. */
5579 e0 = single_succ_edge (cond_bb);
5580 e0->flags &= ~EDGE_FALLTHRU;
5581 e0->flags |= EDGE_FALSE_VALUE;
5584 struct cfg_hooks tree_cfg_hooks = {
5586 tree_verify_flow_info,
5587 tree_dump_bb, /* dump_bb */
5588 create_bb, /* create_basic_block */
5589 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5590 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5591 remove_bb, /* delete_basic_block */
5592 tree_split_block, /* split_block */
5593 tree_move_block_after, /* move_block_after */
5594 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5595 tree_merge_blocks, /* merge_blocks */
5596 tree_predict_edge, /* predict_edge */
5597 tree_predicted_by_p, /* predicted_by_p */
5598 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5599 tree_duplicate_bb, /* duplicate_block */
5600 tree_split_edge, /* split_edge */
5601 tree_make_forwarder_block, /* make_forward_block */
5602 NULL, /* tidy_fallthru_edge */
5603 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5604 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5605 tree_flow_call_edges_add, /* flow_call_edges_add */
5606 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5607 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5608 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5609 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5610 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5611 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5612 flush_pending_stmts /* flush_pending_stmts */
5616 /* Split all critical edges. */
5619 split_critical_edges (void)
5625 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5626 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5627 mappings around the calls to split_edge. */
5628 start_recording_case_labels ();
5631 FOR_EACH_EDGE (e, ei, bb->succs)
5632 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5637 end_recording_case_labels ();
5641 struct tree_opt_pass pass_split_crit_edges =
5643 "crited", /* name */
5645 split_critical_edges, /* execute */
5648 0, /* static_pass_number */
5649 TV_TREE_SPLIT_EDGES, /* tv_id */
5650 PROP_cfg, /* properties required */
5651 PROP_no_crit_edges, /* properties_provided */
5652 0, /* properties_destroyed */
5653 0, /* todo_flags_start */
5654 TODO_dump_func, /* todo_flags_finish */
5659 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5660 a temporary, make sure and register it to be renamed if necessary,
5661 and finally return the temporary. Put the statements to compute
5662 EXP before the current statement in BSI. */
5665 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5667 tree t, new_stmt, orig_stmt;
5669 if (is_gimple_val (exp))
5672 t = make_rename_temp (type, NULL);
5673 new_stmt = build2 (MODIFY_EXPR, type, t, exp);
5675 orig_stmt = bsi_stmt (*bsi);
5676 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5677 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5679 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5681 mark_new_vars_to_rename (new_stmt);
5686 /* Build a ternary operation and gimplify it. Emit code before BSI.
5687 Return the gimple_val holding the result. */
5690 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5691 tree type, tree a, tree b, tree c)
5695 ret = fold_build3 (code, type, a, b, c);
5698 return gimplify_val (bsi, type, ret);
5701 /* Build a binary operation and gimplify it. Emit code before BSI.
5702 Return the gimple_val holding the result. */
5705 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5706 tree type, tree a, tree b)
5710 ret = fold_build2 (code, type, a, b);
5713 return gimplify_val (bsi, type, ret);
5716 /* Build a unary operation and gimplify it. Emit code before BSI.
5717 Return the gimple_val holding the result. */
5720 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5725 ret = fold_build1 (code, type, a);
5728 return gimplify_val (bsi, type, ret);
5733 /* Emit return warnings. */
5736 execute_warn_function_return (void)
5738 #ifdef USE_MAPPED_LOCATION
5739 source_location location;
5747 /* If we have a path to EXIT, then we do return. */
5748 if (TREE_THIS_VOLATILE (cfun->decl)
5749 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5751 #ifdef USE_MAPPED_LOCATION
5752 location = UNKNOWN_LOCATION;
5756 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5758 last = last_stmt (e->src);
5759 if (TREE_CODE (last) == RETURN_EXPR
5760 #ifdef USE_MAPPED_LOCATION
5761 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5763 && (locus = EXPR_LOCUS (last)) != NULL)
5767 #ifdef USE_MAPPED_LOCATION
5768 if (location == UNKNOWN_LOCATION)
5769 location = cfun->function_end_locus;
5770 warning (0, "%H%<noreturn%> function does return", &location);
5773 locus = &cfun->function_end_locus;
5774 warning (0, "%H%<noreturn%> function does return", locus);
5778 /* If we see "return;" in some basic block, then we do reach the end
5779 without returning a value. */
5780 else if (warn_return_type
5781 && !TREE_NO_WARNING (cfun->decl)
5782 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5783 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5785 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5787 tree last = last_stmt (e->src);
5788 if (TREE_CODE (last) == RETURN_EXPR
5789 && TREE_OPERAND (last, 0) == NULL
5790 && !TREE_NO_WARNING (last))
5792 #ifdef USE_MAPPED_LOCATION
5793 location = EXPR_LOCATION (last);
5794 if (location == UNKNOWN_LOCATION)
5795 location = cfun->function_end_locus;
5796 warning (0, "%Hcontrol reaches end of non-void function", &location);
5798 locus = EXPR_LOCUS (last);
5800 locus = &cfun->function_end_locus;
5801 warning (0, "%Hcontrol reaches end of non-void function", locus);
5803 TREE_NO_WARNING (cfun->decl) = 1;
5812 /* Given a basic block B which ends with a conditional and has
5813 precisely two successors, determine which of the edges is taken if
5814 the conditional is true and which is taken if the conditional is
5815 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5818 extract_true_false_edges_from_block (basic_block b,
5822 edge e = EDGE_SUCC (b, 0);
5824 if (e->flags & EDGE_TRUE_VALUE)
5827 *false_edge = EDGE_SUCC (b, 1);
5832 *true_edge = EDGE_SUCC (b, 1);
5836 struct tree_opt_pass pass_warn_function_return =
5840 execute_warn_function_return, /* execute */
5843 0, /* static_pass_number */
5845 PROP_cfg, /* properties_required */
5846 0, /* properties_provided */
5847 0, /* properties_destroyed */
5848 0, /* todo_flags_start */
5849 0, /* todo_flags_finish */
5853 /* Emit noreturn warnings. */
5856 execute_warn_function_noreturn (void)
5858 if (warn_missing_noreturn
5859 && !TREE_THIS_VOLATILE (cfun->decl)
5860 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5861 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5862 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5863 "for attribute %<noreturn%>",
5868 struct tree_opt_pass pass_warn_function_noreturn =
5872 execute_warn_function_noreturn, /* execute */
5875 0, /* static_pass_number */
5877 PROP_cfg, /* properties_required */
5878 0, /* properties_provided */
5879 0, /* properties_destroyed */
5880 0, /* todo_flags_start */
5881 0, /* todo_flags_finish */