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 /* APPLE LOCAL begin for-fsf-4_4 3274130 5295549 */ \
1055 /* Finally, purge dead labels. All user-defined labels, labels that
1056 can be the target of non-local gotos, labels which have their
1057 address taken and labels which have attributes or alignment are
1059 /* APPLE LOCAL end for-fsf-4_4 3274130 5295549 */ \
1062 block_stmt_iterator i;
1063 tree label_for_this_bb = label_for_bb[bb->index];
1065 if (! label_for_this_bb)
1068 for (i = bsi_start (bb); !bsi_end_p (i); )
1070 tree label, stmt = bsi_stmt (i);
1072 if (TREE_CODE (stmt) != LABEL_EXPR)
1075 label = LABEL_EXPR_LABEL (stmt);
1077 if (label == label_for_this_bb
1078 || ! DECL_ARTIFICIAL (label)
1079 /* APPLE LOCAL begin for-fsf-4_4 3274130 5295549 */ \
1080 || DECL_ATTRIBUTES (label)
1081 || DECL_USER_ALIGN (label)
1082 /* APPLE LOCAL end for-fsf-4_4 3274130 5295549 */ \
1083 || DECL_NONLOCAL (label)
1084 || FORCED_LABEL (label))
1087 bsi_remove (&i, true);
1091 free (label_for_bb);
1094 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1095 and scan the sorted vector of cases. Combine the ones jumping to the
1097 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1100 group_case_labels (void)
1106 tree stmt = last_stmt (bb);
1107 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1109 tree labels = SWITCH_LABELS (stmt);
1110 int old_size = TREE_VEC_LENGTH (labels);
1111 int i, j, new_size = old_size;
1112 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1115 /* The default label is always the last case in a switch
1116 statement after gimplification. */
1117 default_label = CASE_LABEL (default_case);
1119 /* Look for possible opportunities to merge cases.
1120 Ignore the last element of the label vector because it
1121 must be the default case. */
1123 while (i < old_size - 1)
1125 tree base_case, base_label, base_high;
1126 base_case = TREE_VEC_ELT (labels, i);
1128 gcc_assert (base_case);
1129 base_label = CASE_LABEL (base_case);
1131 /* Discard cases that have the same destination as the
1133 if (base_label == default_label)
1135 TREE_VEC_ELT (labels, i) = NULL_TREE;
1141 base_high = CASE_HIGH (base_case) ?
1142 CASE_HIGH (base_case) : CASE_LOW (base_case);
1144 /* Try to merge case labels. Break out when we reach the end
1145 of the label vector or when we cannot merge the next case
1146 label with the current one. */
1147 while (i < old_size - 1)
1149 tree merge_case = TREE_VEC_ELT (labels, i);
1150 tree merge_label = CASE_LABEL (merge_case);
1151 tree t = int_const_binop (PLUS_EXPR, base_high,
1152 integer_one_node, 1);
1154 /* Merge the cases if they jump to the same place,
1155 and their ranges are consecutive. */
1156 if (merge_label == base_label
1157 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1159 base_high = CASE_HIGH (merge_case) ?
1160 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1161 CASE_HIGH (base_case) = base_high;
1162 TREE_VEC_ELT (labels, i) = NULL_TREE;
1171 /* Compress the case labels in the label vector, and adjust the
1172 length of the vector. */
1173 for (i = 0, j = 0; i < new_size; i++)
1175 while (! TREE_VEC_ELT (labels, j))
1177 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1179 TREE_VEC_LENGTH (labels) = new_size;
1184 /* Checks whether we can merge block B into block A. */
1187 tree_can_merge_blocks_p (basic_block a, basic_block b)
1190 block_stmt_iterator bsi;
1193 if (!single_succ_p (a))
1196 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1199 if (single_succ (a) != b)
1202 if (!single_pred_p (b))
1205 if (b == EXIT_BLOCK_PTR)
1208 /* If A ends by a statement causing exceptions or something similar, we
1209 cannot merge the blocks. */
1210 stmt = last_stmt (a);
1211 if (stmt && stmt_ends_bb_p (stmt))
1214 /* Do not allow a block with only a non-local label to be merged. */
1215 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1216 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1219 /* It must be possible to eliminate all phi nodes in B. If ssa form
1220 is not up-to-date, we cannot eliminate any phis. */
1221 phi = phi_nodes (b);
1224 if (need_ssa_update_p ())
1227 for (; phi; phi = PHI_CHAIN (phi))
1228 if (!is_gimple_reg (PHI_RESULT (phi))
1229 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1233 /* Do not remove user labels. */
1234 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1236 stmt = bsi_stmt (bsi);
1237 if (TREE_CODE (stmt) != LABEL_EXPR)
1239 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1243 /* Protect the loop latches. */
1245 && b->loop_father->latch == b)
1251 /* Replaces all uses of NAME by VAL. */
1254 replace_uses_by (tree name, tree val)
1256 imm_use_iterator imm_iter;
1263 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1265 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1267 replace_exp (use, val);
1269 if (TREE_CODE (stmt) == PHI_NODE)
1271 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1272 if (e->flags & EDGE_ABNORMAL)
1274 /* This can only occur for virtual operands, since
1275 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1276 would prevent replacement. */
1277 gcc_assert (!is_gimple_reg (name));
1278 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1282 if (TREE_CODE (stmt) != PHI_NODE)
1286 fold_stmt_inplace (stmt);
1287 rhs = get_rhs (stmt);
1288 if (TREE_CODE (rhs) == ADDR_EXPR)
1289 recompute_tree_invariant_for_addr_expr (rhs);
1291 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1292 mark_new_vars_to_rename (stmt);
1296 gcc_assert (num_imm_uses (name) == 0);
1298 /* Also update the trees stored in loop structures. */
1303 for (i = 0; i < current_loops->num; i++)
1305 loop = current_loops->parray[i];
1307 substitute_in_loop_info (loop, name, val);
1312 /* Merge block B into block A. */
1315 tree_merge_blocks (basic_block a, basic_block b)
1317 block_stmt_iterator bsi;
1318 tree_stmt_iterator last;
1322 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1324 /* Remove all single-valued PHI nodes from block B of the form
1325 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1327 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1329 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1331 bool may_replace_uses = may_propagate_copy (def, use);
1333 /* In case we have loops to care about, do not propagate arguments of
1334 loop closed ssa phi nodes. */
1336 && is_gimple_reg (def)
1337 && TREE_CODE (use) == SSA_NAME
1338 && a->loop_father != b->loop_father)
1339 may_replace_uses = false;
1341 if (!may_replace_uses)
1343 gcc_assert (is_gimple_reg (def));
1345 /* Note that just emitting the copies is fine -- there is no problem
1346 with ordering of phi nodes. This is because A is the single
1347 predecessor of B, therefore results of the phi nodes cannot
1348 appear as arguments of the phi nodes. */
1349 copy = build2 (MODIFY_EXPR, void_type_node, def, use);
1350 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1351 SET_PHI_RESULT (phi, NULL_TREE);
1352 SSA_NAME_DEF_STMT (def) = copy;
1355 replace_uses_by (def, use);
1357 remove_phi_node (phi, NULL);
1360 /* Ensure that B follows A. */
1361 move_block_after (b, a);
1363 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1364 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1366 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1367 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1369 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1371 tree label = bsi_stmt (bsi);
1373 bsi_remove (&bsi, false);
1374 /* Now that we can thread computed gotos, we might have
1375 a situation where we have a forced label in block B
1376 However, the label at the start of block B might still be
1377 used in other ways (think about the runtime checking for
1378 Fortran assigned gotos). So we can not just delete the
1379 label. Instead we move the label to the start of block A. */
1380 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1382 block_stmt_iterator dest_bsi = bsi_start (a);
1383 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1388 change_bb_for_stmt (bsi_stmt (bsi), a);
1393 /* Merge the chains. */
1394 last = tsi_last (a->stmt_list);
1395 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1396 b->stmt_list = NULL;
1400 /* Return the one of two successors of BB that is not reachable by a
1401 reached by a complex edge, if there is one. Else, return BB. We use
1402 this in optimizations that use post-dominators for their heuristics,
1403 to catch the cases in C++ where function calls are involved. */
1406 single_noncomplex_succ (basic_block bb)
1409 if (EDGE_COUNT (bb->succs) != 2)
1412 e0 = EDGE_SUCC (bb, 0);
1413 e1 = EDGE_SUCC (bb, 1);
1414 if (e0->flags & EDGE_COMPLEX)
1416 if (e1->flags & EDGE_COMPLEX)
1423 /* Walk the function tree removing unnecessary statements.
1425 * Empty statement nodes are removed
1427 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1429 * Unnecessary COND_EXPRs are removed
1431 * Some unnecessary BIND_EXPRs are removed
1433 Clearly more work could be done. The trick is doing the analysis
1434 and removal fast enough to be a net improvement in compile times.
1436 Note that when we remove a control structure such as a COND_EXPR
1437 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1438 to ensure we eliminate all the useless code. */
1449 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1452 remove_useless_stmts_warn_notreached (tree stmt)
1454 if (EXPR_HAS_LOCATION (stmt))
1456 location_t loc = EXPR_LOCATION (stmt);
1457 if (LOCATION_LINE (loc) > 0)
1459 warning (0, "%Hwill never be executed", &loc);
1464 switch (TREE_CODE (stmt))
1466 case STATEMENT_LIST:
1468 tree_stmt_iterator i;
1469 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1470 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1476 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1478 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1480 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1484 case TRY_FINALLY_EXPR:
1485 case TRY_CATCH_EXPR:
1486 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1488 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1493 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1494 case EH_FILTER_EXPR:
1495 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1497 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1500 /* Not a live container. */
1508 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1510 tree then_clause, else_clause, cond;
1511 bool save_has_label, then_has_label, else_has_label;
1513 save_has_label = data->has_label;
1514 data->has_label = false;
1515 data->last_goto = NULL;
1517 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1519 then_has_label = data->has_label;
1520 data->has_label = false;
1521 data->last_goto = NULL;
1523 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1525 else_has_label = data->has_label;
1526 data->has_label = save_has_label | then_has_label | else_has_label;
1528 then_clause = COND_EXPR_THEN (*stmt_p);
1529 else_clause = COND_EXPR_ELSE (*stmt_p);
1530 cond = fold (COND_EXPR_COND (*stmt_p));
1532 /* If neither arm does anything at all, we can remove the whole IF. */
1533 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1535 *stmt_p = build_empty_stmt ();
1536 data->repeat = true;
1539 /* If there are no reachable statements in an arm, then we can
1540 zap the entire conditional. */
1541 else if (integer_nonzerop (cond) && !else_has_label)
1543 if (warn_notreached)
1544 remove_useless_stmts_warn_notreached (else_clause);
1545 *stmt_p = then_clause;
1546 data->repeat = true;
1548 else if (integer_zerop (cond) && !then_has_label)
1550 if (warn_notreached)
1551 remove_useless_stmts_warn_notreached (then_clause);
1552 *stmt_p = else_clause;
1553 data->repeat = true;
1556 /* Check a couple of simple things on then/else with single stmts. */
1559 tree then_stmt = expr_only (then_clause);
1560 tree else_stmt = expr_only (else_clause);
1562 /* Notice branches to a common destination. */
1563 if (then_stmt && else_stmt
1564 && TREE_CODE (then_stmt) == GOTO_EXPR
1565 && TREE_CODE (else_stmt) == GOTO_EXPR
1566 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1568 *stmt_p = then_stmt;
1569 data->repeat = true;
1572 /* If the THEN/ELSE clause merely assigns a value to a variable or
1573 parameter which is already known to contain that value, then
1574 remove the useless THEN/ELSE clause. */
1575 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1578 && TREE_CODE (else_stmt) == MODIFY_EXPR
1579 && TREE_OPERAND (else_stmt, 0) == cond
1580 && integer_zerop (TREE_OPERAND (else_stmt, 1)))
1581 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1583 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1584 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1585 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1586 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1588 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1589 ? then_stmt : else_stmt);
1590 tree *location = (TREE_CODE (cond) == EQ_EXPR
1591 ? &COND_EXPR_THEN (*stmt_p)
1592 : &COND_EXPR_ELSE (*stmt_p));
1595 && TREE_CODE (stmt) == MODIFY_EXPR
1596 && TREE_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1597 && TREE_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1598 *location = alloc_stmt_list ();
1602 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1603 would be re-introduced during lowering. */
1604 data->last_goto = NULL;
1609 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1611 bool save_may_branch, save_may_throw;
1612 bool this_may_branch, this_may_throw;
1614 /* Collect may_branch and may_throw information for the body only. */
1615 save_may_branch = data->may_branch;
1616 save_may_throw = data->may_throw;
1617 data->may_branch = false;
1618 data->may_throw = false;
1619 data->last_goto = NULL;
1621 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1623 this_may_branch = data->may_branch;
1624 this_may_throw = data->may_throw;
1625 data->may_branch |= save_may_branch;
1626 data->may_throw |= save_may_throw;
1627 data->last_goto = NULL;
1629 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1631 /* If the body is empty, then we can emit the FINALLY block without
1632 the enclosing TRY_FINALLY_EXPR. */
1633 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1635 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1636 data->repeat = true;
1639 /* If the handler is empty, then we can emit the TRY block without
1640 the enclosing TRY_FINALLY_EXPR. */
1641 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1643 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1644 data->repeat = true;
1647 /* If the body neither throws, nor branches, then we can safely
1648 string the TRY and FINALLY blocks together. */
1649 else if (!this_may_branch && !this_may_throw)
1651 tree stmt = *stmt_p;
1652 *stmt_p = TREE_OPERAND (stmt, 0);
1653 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1654 data->repeat = true;
1660 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1662 bool save_may_throw, this_may_throw;
1663 tree_stmt_iterator i;
1666 /* Collect may_throw information for the body only. */
1667 save_may_throw = data->may_throw;
1668 data->may_throw = false;
1669 data->last_goto = NULL;
1671 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1673 this_may_throw = data->may_throw;
1674 data->may_throw = save_may_throw;
1676 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1677 if (!this_may_throw)
1679 if (warn_notreached)
1680 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1681 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1682 data->repeat = true;
1686 /* Process the catch clause specially. We may be able to tell that
1687 no exceptions propagate past this point. */
1689 this_may_throw = true;
1690 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1691 stmt = tsi_stmt (i);
1692 data->last_goto = NULL;
1694 switch (TREE_CODE (stmt))
1697 for (; !tsi_end_p (i); tsi_next (&i))
1699 stmt = tsi_stmt (i);
1700 /* If we catch all exceptions, then the body does not
1701 propagate exceptions past this point. */
1702 if (CATCH_TYPES (stmt) == NULL)
1703 this_may_throw = false;
1704 data->last_goto = NULL;
1705 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1709 case EH_FILTER_EXPR:
1710 if (EH_FILTER_MUST_NOT_THROW (stmt))
1711 this_may_throw = false;
1712 else if (EH_FILTER_TYPES (stmt) == NULL)
1713 this_may_throw = false;
1714 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1718 /* Otherwise this is a cleanup. */
1719 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1721 /* If the cleanup is empty, then we can emit the TRY block without
1722 the enclosing TRY_CATCH_EXPR. */
1723 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1725 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1726 data->repeat = true;
1730 data->may_throw |= this_may_throw;
1735 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1739 /* First remove anything underneath the BIND_EXPR. */
1740 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1742 /* If the BIND_EXPR has no variables, then we can pull everything
1743 up one level and remove the BIND_EXPR, unless this is the toplevel
1744 BIND_EXPR for the current function or an inlined function.
1746 When this situation occurs we will want to apply this
1747 optimization again. */
1748 block = BIND_EXPR_BLOCK (*stmt_p);
1749 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1750 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1752 || ! BLOCK_ABSTRACT_ORIGIN (block)
1753 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1756 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1757 data->repeat = true;
1763 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1765 tree dest = GOTO_DESTINATION (*stmt_p);
1767 data->may_branch = true;
1768 data->last_goto = NULL;
1770 /* Record the last goto expr, so that we can delete it if unnecessary. */
1771 if (TREE_CODE (dest) == LABEL_DECL)
1772 data->last_goto = stmt_p;
1777 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1779 tree label = LABEL_EXPR_LABEL (*stmt_p);
1781 data->has_label = true;
1783 /* We do want to jump across non-local label receiver code. */
1784 if (DECL_NONLOCAL (label))
1785 data->last_goto = NULL;
1787 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1789 *data->last_goto = build_empty_stmt ();
1790 data->repeat = true;
1793 /* ??? Add something here to delete unused labels. */
1797 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1798 decl. This allows us to eliminate redundant or useless
1799 calls to "const" functions.
1801 Gimplifier already does the same operation, but we may notice functions
1802 being const and pure once their calls has been gimplified, so we need
1803 to update the flag. */
1806 update_call_expr_flags (tree call)
1808 tree decl = get_callee_fndecl (call);
1811 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1812 TREE_SIDE_EFFECTS (call) = 0;
1813 if (TREE_NOTHROW (decl))
1814 TREE_NOTHROW (call) = 1;
1818 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1821 notice_special_calls (tree t)
1823 int flags = call_expr_flags (t);
1825 if (flags & ECF_MAY_BE_ALLOCA)
1826 current_function_calls_alloca = true;
1827 if (flags & ECF_RETURNS_TWICE)
1828 current_function_calls_setjmp = true;
1832 /* Clear flags set by notice_special_calls. Used by dead code removal
1833 to update the flags. */
1836 clear_special_calls (void)
1838 current_function_calls_alloca = false;
1839 current_function_calls_setjmp = false;
1844 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1848 switch (TREE_CODE (t))
1851 remove_useless_stmts_cond (tp, data);
1854 case TRY_FINALLY_EXPR:
1855 remove_useless_stmts_tf (tp, data);
1858 case TRY_CATCH_EXPR:
1859 remove_useless_stmts_tc (tp, data);
1863 remove_useless_stmts_bind (tp, data);
1867 remove_useless_stmts_goto (tp, data);
1871 remove_useless_stmts_label (tp, data);
1876 data->last_goto = NULL;
1877 data->may_branch = true;
1882 data->last_goto = NULL;
1883 notice_special_calls (t);
1884 update_call_expr_flags (t);
1885 if (tree_could_throw_p (t))
1886 data->may_throw = true;
1890 data->last_goto = NULL;
1892 op = get_call_expr_in (t);
1895 update_call_expr_flags (op);
1896 notice_special_calls (op);
1898 if (tree_could_throw_p (t))
1899 data->may_throw = true;
1902 case STATEMENT_LIST:
1904 tree_stmt_iterator i = tsi_start (t);
1905 while (!tsi_end_p (i))
1908 if (IS_EMPTY_STMT (t))
1914 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1917 if (TREE_CODE (t) == STATEMENT_LIST)
1919 tsi_link_before (&i, t, TSI_SAME_STMT);
1929 data->last_goto = NULL;
1933 data->last_goto = NULL;
1939 remove_useless_stmts (void)
1941 struct rus_data data;
1943 clear_special_calls ();
1947 memset (&data, 0, sizeof (data));
1948 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1950 while (data.repeat);
1955 struct tree_opt_pass pass_remove_useless_stmts =
1957 "useless", /* name */
1959 remove_useless_stmts, /* execute */
1962 0, /* static_pass_number */
1964 PROP_gimple_any, /* properties_required */
1965 0, /* properties_provided */
1966 0, /* properties_destroyed */
1967 0, /* todo_flags_start */
1968 TODO_dump_func, /* todo_flags_finish */
1972 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1975 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1979 /* Since this block is no longer reachable, we can just delete all
1980 of its PHI nodes. */
1981 phi = phi_nodes (bb);
1984 tree next = PHI_CHAIN (phi);
1985 remove_phi_node (phi, NULL_TREE);
1989 /* Remove edges to BB's successors. */
1990 while (EDGE_COUNT (bb->succs) > 0)
1991 remove_edge (EDGE_SUCC (bb, 0));
1995 /* Remove statements of basic block BB. */
1998 remove_bb (basic_block bb)
2000 block_stmt_iterator i;
2001 #ifdef USE_MAPPED_LOCATION
2002 source_location loc = UNKNOWN_LOCATION;
2004 source_locus loc = 0;
2009 fprintf (dump_file, "Removing basic block %d\n", bb->index);
2010 if (dump_flags & TDF_DETAILS)
2012 dump_bb (bb, dump_file, 0);
2013 fprintf (dump_file, "\n");
2017 /* If we remove the header or the latch of a loop, mark the loop for
2018 removal by setting its header and latch to NULL. */
2021 struct loop *loop = bb->loop_father;
2023 if (loop->latch == bb
2024 || loop->header == bb)
2027 loop->header = NULL;
2029 /* Also clean up the information associated with the loop. Updating
2030 it would waste time. More importantly, it may refer to ssa
2031 names that were defined in other removed basic block -- these
2032 ssa names are now removed and invalid. */
2033 free_numbers_of_iterations_estimates_loop (loop);
2037 /* Remove all the instructions in the block. */
2038 for (i = bsi_start (bb); !bsi_end_p (i);)
2040 tree stmt = bsi_stmt (i);
2041 if (TREE_CODE (stmt) == LABEL_EXPR
2042 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2043 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2046 block_stmt_iterator new_bsi;
2048 /* A non-reachable non-local label may still be referenced.
2049 But it no longer needs to carry the extra semantics of
2051 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2053 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2054 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2057 new_bb = bb->prev_bb;
2058 new_bsi = bsi_start (new_bb);
2059 bsi_remove (&i, false);
2060 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2064 /* Release SSA definitions if we are in SSA. Note that we
2065 may be called when not in SSA. For example,
2066 final_cleanup calls this function via
2067 cleanup_tree_cfg. */
2069 release_defs (stmt);
2071 bsi_remove (&i, true);
2074 /* Don't warn for removed gotos. Gotos are often removed due to
2075 jump threading, thus resulting in bogus warnings. Not great,
2076 since this way we lose warnings for gotos in the original
2077 program that are indeed unreachable. */
2078 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2080 #ifdef USE_MAPPED_LOCATION
2081 if (EXPR_HAS_LOCATION (stmt))
2082 loc = EXPR_LOCATION (stmt);
2085 t = EXPR_LOCUS (stmt);
2086 if (t && LOCATION_LINE (*t) > 0)
2092 /* If requested, give a warning that the first statement in the
2093 block is unreachable. We walk statements backwards in the
2094 loop above, so the last statement we process is the first statement
2096 #ifdef USE_MAPPED_LOCATION
2097 if (loc > BUILTINS_LOCATION)
2098 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2101 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2104 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2108 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2109 predicate VAL, return the edge that will be taken out of the block.
2110 If VAL does not match a unique edge, NULL is returned. */
2113 find_taken_edge (basic_block bb, tree val)
2117 stmt = last_stmt (bb);
2120 gcc_assert (is_ctrl_stmt (stmt));
2123 if (! is_gimple_min_invariant (val))
2126 if (TREE_CODE (stmt) == COND_EXPR)
2127 return find_taken_edge_cond_expr (bb, val);
2129 if (TREE_CODE (stmt) == SWITCH_EXPR)
2130 return find_taken_edge_switch_expr (bb, val);
2132 if (computed_goto_p (stmt))
2134 /* Only optimize if the argument is a label, if the argument is
2135 not a label then we can not construct a proper CFG.
2137 It may be the case that we only need to allow the LABEL_REF to
2138 appear inside an ADDR_EXPR, but we also allow the LABEL_REF to
2139 appear inside a LABEL_EXPR just to be safe. */
2140 if ((TREE_CODE (val) == ADDR_EXPR || TREE_CODE (val) == LABEL_EXPR)
2141 && TREE_CODE (TREE_OPERAND (val, 0)) == LABEL_DECL)
2142 return find_taken_edge_computed_goto (bb, TREE_OPERAND (val, 0));
2149 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2150 statement, determine which of the outgoing edges will be taken out of the
2151 block. Return NULL if either edge may be taken. */
2154 find_taken_edge_computed_goto (basic_block bb, tree val)
2159 dest = label_to_block (val);
2162 e = find_edge (bb, dest);
2163 gcc_assert (e != NULL);
2169 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2170 statement, determine which of the two edges will be taken out of the
2171 block. Return NULL if either edge may be taken. */
2174 find_taken_edge_cond_expr (basic_block bb, tree val)
2176 edge true_edge, false_edge;
2178 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2180 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2181 return (zero_p (val) ? false_edge : true_edge);
2184 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2185 statement, determine which edge will be taken out of the block. Return
2186 NULL if any edge may be taken. */
2189 find_taken_edge_switch_expr (basic_block bb, tree val)
2191 tree switch_expr, taken_case;
2192 basic_block dest_bb;
2195 switch_expr = last_stmt (bb);
2196 taken_case = find_case_label_for_value (switch_expr, val);
2197 dest_bb = label_to_block (CASE_LABEL (taken_case));
2199 e = find_edge (bb, dest_bb);
2205 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2206 We can make optimal use here of the fact that the case labels are
2207 sorted: We can do a binary search for a case matching VAL. */
2210 find_case_label_for_value (tree switch_expr, tree val)
2212 tree vec = SWITCH_LABELS (switch_expr);
2213 size_t low, high, n = TREE_VEC_LENGTH (vec);
2214 tree default_case = TREE_VEC_ELT (vec, n - 1);
2216 for (low = -1, high = n - 1; high - low > 1; )
2218 size_t i = (high + low) / 2;
2219 tree t = TREE_VEC_ELT (vec, i);
2222 /* Cache the result of comparing CASE_LOW and val. */
2223 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2230 if (CASE_HIGH (t) == NULL)
2232 /* A singe-valued case label. */
2238 /* A case range. We can only handle integer ranges. */
2239 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2244 return default_case;
2250 /*---------------------------------------------------------------------------
2252 ---------------------------------------------------------------------------*/
2254 /* Dump tree-specific information of block BB to file OUTF. */
2257 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2259 dump_generic_bb (outf, bb, indent, TDF_VOPS);
2263 /* Dump a basic block on stderr. */
2266 debug_tree_bb (basic_block bb)
2268 dump_bb (bb, stderr, 0);
2272 /* Dump basic block with index N on stderr. */
2275 debug_tree_bb_n (int n)
2277 debug_tree_bb (BASIC_BLOCK (n));
2278 return BASIC_BLOCK (n);
2282 /* Dump the CFG on stderr.
2284 FLAGS are the same used by the tree dumping functions
2285 (see TDF_* in tree-pass.h). */
2288 debug_tree_cfg (int flags)
2290 dump_tree_cfg (stderr, flags);
2294 /* Dump the program showing basic block boundaries on the given FILE.
2296 FLAGS are the same used by the tree dumping functions (see TDF_* in
2300 dump_tree_cfg (FILE *file, int flags)
2302 if (flags & TDF_DETAILS)
2304 const char *funcname
2305 = lang_hooks.decl_printable_name (current_function_decl, 2);
2308 fprintf (file, ";; Function %s\n\n", funcname);
2309 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2310 n_basic_blocks, n_edges, last_basic_block);
2312 brief_dump_cfg (file);
2313 fprintf (file, "\n");
2316 if (flags & TDF_STATS)
2317 dump_cfg_stats (file);
2319 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2323 /* Dump CFG statistics on FILE. */
2326 dump_cfg_stats (FILE *file)
2328 static long max_num_merged_labels = 0;
2329 unsigned long size, total = 0;
2332 const char * const fmt_str = "%-30s%-13s%12s\n";
2333 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2334 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2335 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2336 const char *funcname
2337 = lang_hooks.decl_printable_name (current_function_decl, 2);
2340 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2342 fprintf (file, "---------------------------------------------------------\n");
2343 fprintf (file, fmt_str, "", " Number of ", "Memory");
2344 fprintf (file, fmt_str, "", " instances ", "used ");
2345 fprintf (file, "---------------------------------------------------------\n");
2347 size = n_basic_blocks * sizeof (struct basic_block_def);
2349 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2350 SCALE (size), LABEL (size));
2354 num_edges += EDGE_COUNT (bb->succs);
2355 size = num_edges * sizeof (struct edge_def);
2357 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2359 fprintf (file, "---------------------------------------------------------\n");
2360 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2362 fprintf (file, "---------------------------------------------------------\n");
2363 fprintf (file, "\n");
2365 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2366 max_num_merged_labels = cfg_stats.num_merged_labels;
2368 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2369 cfg_stats.num_merged_labels, max_num_merged_labels);
2371 fprintf (file, "\n");
2375 /* Dump CFG statistics on stderr. Keep extern so that it's always
2376 linked in the final executable. */
2379 debug_cfg_stats (void)
2381 dump_cfg_stats (stderr);
2385 /* Dump the flowgraph to a .vcg FILE. */
2388 tree_cfg2vcg (FILE *file)
2393 const char *funcname
2394 = lang_hooks.decl_printable_name (current_function_decl, 2);
2396 /* Write the file header. */
2397 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2398 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2399 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2401 /* Write blocks and edges. */
2402 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2404 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2407 if (e->flags & EDGE_FAKE)
2408 fprintf (file, " linestyle: dotted priority: 10");
2410 fprintf (file, " linestyle: solid priority: 100");
2412 fprintf (file, " }\n");
2418 enum tree_code head_code, end_code;
2419 const char *head_name, *end_name;
2422 tree first = first_stmt (bb);
2423 tree last = last_stmt (bb);
2427 head_code = TREE_CODE (first);
2428 head_name = tree_code_name[head_code];
2429 head_line = get_lineno (first);
2432 head_name = "no-statement";
2436 end_code = TREE_CODE (last);
2437 end_name = tree_code_name[end_code];
2438 end_line = get_lineno (last);
2441 end_name = "no-statement";
2443 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2444 bb->index, bb->index, head_name, head_line, end_name,
2447 FOR_EACH_EDGE (e, ei, bb->succs)
2449 if (e->dest == EXIT_BLOCK_PTR)
2450 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2452 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2454 if (e->flags & EDGE_FAKE)
2455 fprintf (file, " priority: 10 linestyle: dotted");
2457 fprintf (file, " priority: 100 linestyle: solid");
2459 fprintf (file, " }\n");
2462 if (bb->next_bb != EXIT_BLOCK_PTR)
2466 fputs ("}\n\n", file);
2471 /*---------------------------------------------------------------------------
2472 Miscellaneous helpers
2473 ---------------------------------------------------------------------------*/
2475 /* Return true if T represents a stmt that always transfers control. */
2478 is_ctrl_stmt (tree t)
2480 return (TREE_CODE (t) == COND_EXPR
2481 || TREE_CODE (t) == SWITCH_EXPR
2482 || TREE_CODE (t) == GOTO_EXPR
2483 || TREE_CODE (t) == RETURN_EXPR
2484 || TREE_CODE (t) == RESX_EXPR);
2488 /* Return true if T is a statement that may alter the flow of control
2489 (e.g., a call to a non-returning function). */
2492 is_ctrl_altering_stmt (tree t)
2497 call = get_call_expr_in (t);
2500 /* A non-pure/const CALL_EXPR alters flow control if the current
2501 function has nonlocal labels. */
2502 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2505 /* A CALL_EXPR also alters control flow if it does not return. */
2506 if (call_expr_flags (call) & ECF_NORETURN)
2510 /* OpenMP directives alter control flow. */
2511 if (OMP_DIRECTIVE_P (t))
2514 /* If a statement can throw, it alters control flow. */
2515 return tree_can_throw_internal (t);
2519 /* Return true if T is a computed goto. */
2522 computed_goto_p (tree t)
2524 return (TREE_CODE (t) == GOTO_EXPR
2525 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2529 /* Return true if T is a simple local goto. */
2532 simple_goto_p (tree t)
2534 return (TREE_CODE (t) == GOTO_EXPR
2535 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2539 /* Return true if T can make an abnormal transfer of control flow.
2540 Transfers of control flow associated with EH are excluded. */
2543 tree_can_make_abnormal_goto (tree t)
2545 if (computed_goto_p (t))
2547 if (TREE_CODE (t) == MODIFY_EXPR)
2548 t = TREE_OPERAND (t, 1);
2549 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2550 t = TREE_OPERAND (t, 0);
2551 if (TREE_CODE (t) == CALL_EXPR)
2552 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2557 /* Return true if T should start a new basic block. PREV_T is the
2558 statement preceding T. It is used when T is a label or a case label.
2559 Labels should only start a new basic block if their previous statement
2560 wasn't a label. Otherwise, sequence of labels would generate
2561 unnecessary basic blocks that only contain a single label. */
2564 stmt_starts_bb_p (tree t, tree prev_t)
2569 /* LABEL_EXPRs start a new basic block only if the preceding
2570 statement wasn't a label of the same type. This prevents the
2571 creation of consecutive blocks that have nothing but a single
2573 if (TREE_CODE (t) == LABEL_EXPR)
2575 /* Nonlocal and computed GOTO targets always start a new block. */
2576 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2577 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2580 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2582 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2585 cfg_stats.num_merged_labels++;
2596 /* Return true if T should end a basic block. */
2599 stmt_ends_bb_p (tree t)
2601 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2605 /* Add gotos that used to be represented implicitly in the CFG. */
2608 disband_implicit_edges (void)
2611 block_stmt_iterator last;
2618 last = bsi_last (bb);
2619 stmt = last_stmt (bb);
2621 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2623 /* Remove superfluous gotos from COND_EXPR branches. Moved
2624 from cfg_remove_useless_stmts here since it violates the
2625 invariants for tree--cfg correspondence and thus fits better
2626 here where we do it anyway. */
2627 e = find_edge (bb, bb->next_bb);
2630 if (e->flags & EDGE_TRUE_VALUE)
2631 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2632 else if (e->flags & EDGE_FALSE_VALUE)
2633 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2636 e->flags |= EDGE_FALLTHRU;
2642 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2644 /* Remove the RETURN_EXPR if we may fall though to the exit
2646 gcc_assert (single_succ_p (bb));
2647 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2649 if (bb->next_bb == EXIT_BLOCK_PTR
2650 && !TREE_OPERAND (stmt, 0))
2652 bsi_remove (&last, true);
2653 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2658 /* There can be no fallthru edge if the last statement is a control
2660 if (stmt && is_ctrl_stmt (stmt))
2663 /* Find a fallthru edge and emit the goto if necessary. */
2664 FOR_EACH_EDGE (e, ei, bb->succs)
2665 if (e->flags & EDGE_FALLTHRU)
2668 if (!e || e->dest == bb->next_bb)
2671 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2672 label = tree_block_label (e->dest);
2674 stmt = build1 (GOTO_EXPR, void_type_node, label);
2675 #ifdef USE_MAPPED_LOCATION
2676 SET_EXPR_LOCATION (stmt, e->goto_locus);
2678 SET_EXPR_LOCUS (stmt, e->goto_locus);
2680 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2681 e->flags &= ~EDGE_FALLTHRU;
2685 /* Remove block annotations and other datastructures. */
2688 delete_tree_cfg_annotations (void)
2690 label_to_block_map = NULL;
2694 /* Return the first statement in basic block BB. */
2697 first_stmt (basic_block bb)
2699 block_stmt_iterator i = bsi_start (bb);
2700 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2704 /* Return the last statement in basic block BB. */
2707 last_stmt (basic_block bb)
2709 block_stmt_iterator b = bsi_last (bb);
2710 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2714 /* Return a pointer to the last statement in block BB. */
2717 last_stmt_ptr (basic_block bb)
2719 block_stmt_iterator last = bsi_last (bb);
2720 return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL;
2724 /* Return the last statement of an otherwise empty block. Return NULL
2725 if the block is totally empty, or if it contains more than one
2729 last_and_only_stmt (basic_block bb)
2731 block_stmt_iterator i = bsi_last (bb);
2737 last = bsi_stmt (i);
2742 /* Empty statements should no longer appear in the instruction stream.
2743 Everything that might have appeared before should be deleted by
2744 remove_useless_stmts, and the optimizers should just bsi_remove
2745 instead of smashing with build_empty_stmt.
2747 Thus the only thing that should appear here in a block containing
2748 one executable statement is a label. */
2749 prev = bsi_stmt (i);
2750 if (TREE_CODE (prev) == LABEL_EXPR)
2757 /* Mark BB as the basic block holding statement T. */
2760 set_bb_for_stmt (tree t, basic_block bb)
2762 if (TREE_CODE (t) == PHI_NODE)
2764 else if (TREE_CODE (t) == STATEMENT_LIST)
2766 tree_stmt_iterator i;
2767 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2768 set_bb_for_stmt (tsi_stmt (i), bb);
2772 stmt_ann_t ann = get_stmt_ann (t);
2775 /* If the statement is a label, add the label to block-to-labels map
2776 so that we can speed up edge creation for GOTO_EXPRs. */
2777 if (TREE_CODE (t) == LABEL_EXPR)
2781 t = LABEL_EXPR_LABEL (t);
2782 uid = LABEL_DECL_UID (t);
2785 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2786 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2787 if (old_len <= (unsigned) uid)
2790 unsigned new_len = 3 * uid / 2;
2792 VEC_safe_grow (basic_block, gc, label_to_block_map,
2794 addr = VEC_address (basic_block, label_to_block_map);
2795 memset (&addr[old_len],
2796 0, sizeof (basic_block) * (new_len - old_len));
2800 /* We're moving an existing label. Make sure that we've
2801 removed it from the old block. */
2803 || !VEC_index (basic_block, label_to_block_map, uid));
2804 VEC_replace (basic_block, label_to_block_map, uid, bb);
2809 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2810 from one basic block to another.
2811 For BB splitting we can run into quadratic case, so performance is quite
2812 important and knowing that the tables are big enough, change_bb_for_stmt
2813 can inline as leaf function. */
2815 change_bb_for_stmt (tree t, basic_block bb)
2817 get_stmt_ann (t)->bb = bb;
2818 if (TREE_CODE (t) == LABEL_EXPR)
2819 VEC_replace (basic_block, label_to_block_map,
2820 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2823 /* Finds iterator for STMT. */
2825 extern block_stmt_iterator
2826 bsi_for_stmt (tree stmt)
2828 block_stmt_iterator bsi;
2830 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2831 if (bsi_stmt (bsi) == stmt)
2837 /* Mark statement T as modified, and update it. */
2839 update_modified_stmts (tree t)
2841 if (TREE_CODE (t) == STATEMENT_LIST)
2843 tree_stmt_iterator i;
2845 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2847 stmt = tsi_stmt (i);
2848 update_stmt_if_modified (stmt);
2852 update_stmt_if_modified (t);
2855 /* Insert statement (or statement list) T before the statement
2856 pointed-to by iterator I. M specifies how to update iterator I
2857 after insertion (see enum bsi_iterator_update). */
2860 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2862 set_bb_for_stmt (t, i->bb);
2863 update_modified_stmts (t);
2864 tsi_link_before (&i->tsi, t, (enum tsi_iterator_update) m);
2868 /* Insert statement (or statement list) T after the statement
2869 pointed-to by iterator I. M specifies how to update iterator I
2870 after insertion (see enum bsi_iterator_update). */
2873 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2875 set_bb_for_stmt (t, i->bb);
2876 update_modified_stmts (t);
2877 tsi_link_after (&i->tsi, t, (enum tsi_iterator_update) m);
2881 /* Remove the statement pointed to by iterator I. The iterator is updated
2882 to the next statement.
2884 When REMOVE_EH_INFO is true we remove the statement pointed to by
2885 iterator I from the EH tables. Otherwise we do not modify the EH
2888 Generally, REMOVE_EH_INFO should be true when the statement is going to
2889 be removed from the IL and not reinserted elsewhere. */
2892 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2894 tree t = bsi_stmt (*i);
2895 set_bb_for_stmt (t, NULL);
2896 delink_stmt_imm_use (t);
2897 tsi_delink (&i->tsi);
2898 mark_stmt_modified (t);
2900 remove_stmt_from_eh_region (t);
2904 /* Move the statement at FROM so it comes right after the statement at TO. */
2907 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2909 tree stmt = bsi_stmt (*from);
2910 bsi_remove (from, false);
2911 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2915 /* Move the statement at FROM so it comes right before the statement at TO. */
2918 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2920 tree stmt = bsi_stmt (*from);
2921 bsi_remove (from, false);
2922 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2926 /* Move the statement at FROM to the end of basic block BB. */
2929 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2931 block_stmt_iterator last = bsi_last (bb);
2933 /* Have to check bsi_end_p because it could be an empty block. */
2934 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2935 bsi_move_before (from, &last);
2937 bsi_move_after (from, &last);
2941 /* Replace the contents of the statement pointed to by iterator BSI
2942 with STMT. If UPDATE_EH_INFO is true, the exception handling
2943 information of the original statement is moved to the new statement. */
2946 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2949 tree orig_stmt = bsi_stmt (*bsi);
2951 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2952 set_bb_for_stmt (stmt, bsi->bb);
2954 /* Preserve EH region information from the original statement, if
2955 requested by the caller. */
2958 eh_region = lookup_stmt_eh_region (orig_stmt);
2961 remove_stmt_from_eh_region (orig_stmt);
2962 add_stmt_to_eh_region (stmt, eh_region);
2966 delink_stmt_imm_use (orig_stmt);
2967 *bsi_stmt_ptr (*bsi) = stmt;
2968 mark_stmt_modified (stmt);
2969 update_modified_stmts (stmt);
2973 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2974 is made to place the statement in an existing basic block, but
2975 sometimes that isn't possible. When it isn't possible, the edge is
2976 split and the statement is added to the new block.
2978 In all cases, the returned *BSI points to the correct location. The
2979 return value is true if insertion should be done after the location,
2980 or false if it should be done before the location. If new basic block
2981 has to be created, it is stored in *NEW_BB. */
2984 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2985 basic_block *new_bb)
2987 basic_block dest, src;
2993 /* If the destination has one predecessor which has no PHI nodes,
2994 insert there. Except for the exit block.
2996 The requirement for no PHI nodes could be relaxed. Basically we
2997 would have to examine the PHIs to prove that none of them used
2998 the value set by the statement we want to insert on E. That
2999 hardly seems worth the effort. */
3000 if (single_pred_p (dest)
3001 && ! phi_nodes (dest)
3002 && dest != EXIT_BLOCK_PTR)
3004 *bsi = bsi_start (dest);
3005 if (bsi_end_p (*bsi))
3008 /* Make sure we insert after any leading labels. */
3009 tmp = bsi_stmt (*bsi);
3010 while (TREE_CODE (tmp) == LABEL_EXPR)
3013 if (bsi_end_p (*bsi))
3015 tmp = bsi_stmt (*bsi);
3018 if (bsi_end_p (*bsi))
3020 *bsi = bsi_last (dest);
3027 /* If the source has one successor, the edge is not abnormal and
3028 the last statement does not end a basic block, insert there.
3029 Except for the entry block. */
3031 if ((e->flags & EDGE_ABNORMAL) == 0
3032 && single_succ_p (src)
3033 && src != ENTRY_BLOCK_PTR)
3035 *bsi = bsi_last (src);
3036 if (bsi_end_p (*bsi))
3039 tmp = bsi_stmt (*bsi);
3040 if (!stmt_ends_bb_p (tmp))
3043 /* Insert code just before returning the value. We may need to decompose
3044 the return in the case it contains non-trivial operand. */
3045 if (TREE_CODE (tmp) == RETURN_EXPR)
3047 tree op = TREE_OPERAND (tmp, 0);
3048 if (op && !is_gimple_val (op))
3050 gcc_assert (TREE_CODE (op) == MODIFY_EXPR);
3051 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3052 TREE_OPERAND (tmp, 0) = TREE_OPERAND (op, 0);
3059 /* Otherwise, create a new basic block, and split this edge. */
3060 dest = split_edge (e);
3063 e = single_pred_edge (dest);
3068 /* This routine will commit all pending edge insertions, creating any new
3069 basic blocks which are necessary. */
3072 bsi_commit_edge_inserts (void)
3078 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3081 FOR_EACH_EDGE (e, ei, bb->succs)
3082 bsi_commit_one_edge_insert (e, NULL);
3086 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3087 to this block, otherwise set it to NULL. */
3090 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3094 if (PENDING_STMT (e))
3096 block_stmt_iterator bsi;
3097 tree stmt = PENDING_STMT (e);
3099 PENDING_STMT (e) = NULL_TREE;
3101 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3102 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3104 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3109 /* Add STMT to the pending list of edge E. No actual insertion is
3110 made until a call to bsi_commit_edge_inserts () is made. */
3113 bsi_insert_on_edge (edge e, tree stmt)
3115 append_to_statement_list (stmt, &PENDING_STMT (e));
3118 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3119 block has to be created, it is returned. */
3122 bsi_insert_on_edge_immediate (edge e, tree stmt)
3124 block_stmt_iterator bsi;
3125 basic_block new_bb = NULL;
3127 gcc_assert (!PENDING_STMT (e));
3129 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3130 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3132 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3137 /*---------------------------------------------------------------------------
3138 Tree specific functions for CFG manipulation
3139 ---------------------------------------------------------------------------*/
3141 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3144 reinstall_phi_args (edge new_edge, edge old_edge)
3148 if (!PENDING_STMT (old_edge))
3151 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3153 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3155 tree result = TREE_PURPOSE (var);
3156 tree arg = TREE_VALUE (var);
3158 gcc_assert (result == PHI_RESULT (phi));
3160 add_phi_arg (phi, arg, new_edge);
3163 PENDING_STMT (old_edge) = NULL;
3166 /* Returns the basic block after which the new basic block created
3167 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3168 near its "logical" location. This is of most help to humans looking
3169 at debugging dumps. */
3172 split_edge_bb_loc (edge edge_in)
3174 basic_block dest = edge_in->dest;
3176 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3177 return edge_in->src;
3179 return dest->prev_bb;
3182 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3183 Abort on abnormal edges. */
3186 tree_split_edge (edge edge_in)
3188 basic_block new_bb, after_bb, dest;
3191 /* Abnormal edges cannot be split. */
3192 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3194 dest = edge_in->dest;
3196 after_bb = split_edge_bb_loc (edge_in);
3198 new_bb = create_empty_bb (after_bb);
3199 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3200 new_bb->count = edge_in->count;
3201 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3202 new_edge->probability = REG_BR_PROB_BASE;
3203 new_edge->count = edge_in->count;
3205 e = redirect_edge_and_branch (edge_in, new_bb);
3207 reinstall_phi_args (new_edge, e);
3213 /* Return true when BB has label LABEL in it. */
3216 has_label_p (basic_block bb, tree label)
3218 block_stmt_iterator bsi;
3220 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3222 tree stmt = bsi_stmt (bsi);
3224 if (TREE_CODE (stmt) != LABEL_EXPR)
3226 if (LABEL_EXPR_LABEL (stmt) == label)
3233 /* Callback for walk_tree, check that all elements with address taken are
3234 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3235 inside a PHI node. */
3238 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3241 bool in_phi = (data != NULL);
3246 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3247 #define CHECK_OP(N, MSG) \
3248 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3249 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3251 switch (TREE_CODE (t))
3254 if (SSA_NAME_IN_FREE_LIST (t))
3256 error ("SSA name in freelist but still referenced");
3262 x = fold (ASSERT_EXPR_COND (t));
3263 if (x == boolean_false_node)
3265 error ("ASSERT_EXPR with an always-false condition");
3271 x = TREE_OPERAND (t, 0);
3272 if (TREE_CODE (x) == BIT_FIELD_REF
3273 && is_gimple_reg (TREE_OPERAND (x, 0)))
3275 error ("GIMPLE register modified with BIT_FIELD_REF");
3284 bool old_side_effects;
3287 bool new_side_effects;
3289 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3290 dead PHIs that take the address of something. But if the PHI
3291 result is dead, the fact that it takes the address of anything
3292 is irrelevant. Because we can not tell from here if a PHI result
3293 is dead, we just skip this check for PHIs altogether. This means
3294 we may be missing "valid" checks, but what can you do?
3295 This was PR19217. */
3299 old_invariant = TREE_INVARIANT (t);
3300 old_constant = TREE_CONSTANT (t);
3301 old_side_effects = TREE_SIDE_EFFECTS (t);
3303 recompute_tree_invariant_for_addr_expr (t);
3304 new_invariant = TREE_INVARIANT (t);
3305 new_side_effects = TREE_SIDE_EFFECTS (t);
3306 new_constant = TREE_CONSTANT (t);
3308 if (old_invariant != new_invariant)
3310 error ("invariant not recomputed when ADDR_EXPR changed");
3314 if (old_constant != new_constant)
3316 error ("constant not recomputed when ADDR_EXPR changed");
3319 if (old_side_effects != new_side_effects)
3321 error ("side effects not recomputed when ADDR_EXPR changed");
3325 /* Skip any references (they will be checked when we recurse down the
3326 tree) and ensure that any variable used as a prefix is marked
3328 for (x = TREE_OPERAND (t, 0);
3329 handled_component_p (x);
3330 x = TREE_OPERAND (x, 0))
3333 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3335 if (!TREE_ADDRESSABLE (x))
3337 error ("address taken, but ADDRESSABLE bit not set");
3344 x = COND_EXPR_COND (t);
3345 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3347 error ("non-boolean used in condition");
3350 if (!is_gimple_condexpr (x))
3352 error ("invalid conditional operand");
3359 case FIX_TRUNC_EXPR:
3361 case FIX_FLOOR_EXPR:
3362 case FIX_ROUND_EXPR:
3367 case NON_LVALUE_EXPR:
3368 case TRUTH_NOT_EXPR:
3369 CHECK_OP (0, "invalid operand to unary operator");
3376 case ARRAY_RANGE_REF:
3378 case VIEW_CONVERT_EXPR:
3379 /* We have a nest of references. Verify that each of the operands
3380 that determine where to reference is either a constant or a variable,
3381 verify that the base is valid, and then show we've already checked
3383 while (handled_component_p (t))
3385 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3386 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3387 else if (TREE_CODE (t) == ARRAY_REF
3388 || TREE_CODE (t) == ARRAY_RANGE_REF)
3390 CHECK_OP (1, "invalid array index");
3391 if (TREE_OPERAND (t, 2))
3392 CHECK_OP (2, "invalid array lower bound");
3393 if (TREE_OPERAND (t, 3))
3394 CHECK_OP (3, "invalid array stride");
3396 else if (TREE_CODE (t) == BIT_FIELD_REF)
3398 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3399 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3402 t = TREE_OPERAND (t, 0);
3405 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3407 error ("invalid reference prefix");
3419 case UNORDERED_EXPR:
3430 case TRUNC_DIV_EXPR:
3432 case FLOOR_DIV_EXPR:
3433 case ROUND_DIV_EXPR:
3434 case TRUNC_MOD_EXPR:
3436 case FLOOR_MOD_EXPR:
3437 case ROUND_MOD_EXPR:
3439 case EXACT_DIV_EXPR:
3449 CHECK_OP (0, "invalid operand to binary operator");
3450 CHECK_OP (1, "invalid operand to binary operator");
3454 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3467 /* Verify STMT, return true if STMT is not in GIMPLE form.
3468 TODO: Implement type checking. */
3471 verify_stmt (tree stmt, bool last_in_block)
3475 if (OMP_DIRECTIVE_P (stmt))
3477 /* OpenMP directives are validated by the FE and never operated
3478 on by the optimizers. Furthermore, OMP_FOR may contain
3479 non-gimple expressions when the main index variable has had
3480 its address taken. This does not affect the loop itself
3481 because the header of an OMP_FOR is merely used to determine
3482 how to setup the parallel iteration. */
3486 if (!is_gimple_stmt (stmt))
3488 error ("is not a valid GIMPLE statement");
3492 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3495 debug_generic_stmt (addr);
3499 /* If the statement is marked as part of an EH region, then it is
3500 expected that the statement could throw. Verify that when we
3501 have optimizations that simplify statements such that we prove
3502 that they cannot throw, that we update other data structures
3504 if (lookup_stmt_eh_region (stmt) >= 0)
3506 if (!tree_could_throw_p (stmt))
3508 error ("statement marked for throw, but doesn%'t");
3511 if (!last_in_block && tree_can_throw_internal (stmt))
3513 error ("statement marked for throw in middle of block");
3521 debug_generic_stmt (stmt);
3526 /* Return true when the T can be shared. */
3529 tree_node_can_be_shared (tree t)
3531 if (IS_TYPE_OR_DECL_P (t)
3532 || is_gimple_min_invariant (t)
3533 || TREE_CODE (t) == SSA_NAME
3534 || t == error_mark_node
3535 || TREE_CODE (t) == IDENTIFIER_NODE)
3538 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3541 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3542 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3543 || TREE_CODE (t) == COMPONENT_REF
3544 || TREE_CODE (t) == REALPART_EXPR
3545 || TREE_CODE (t) == IMAGPART_EXPR)
3546 t = TREE_OPERAND (t, 0);
3555 /* Called via walk_trees. Verify tree sharing. */
3558 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3560 htab_t htab = (htab_t) data;
3563 if (tree_node_can_be_shared (*tp))
3565 *walk_subtrees = false;
3569 slot = htab_find_slot (htab, *tp, INSERT);
3571 return (tree) *slot;
3578 /* Verify the GIMPLE statement chain. */
3584 block_stmt_iterator bsi;
3589 timevar_push (TV_TREE_STMT_VERIFY);
3590 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3597 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3599 int phi_num_args = PHI_NUM_ARGS (phi);
3601 if (bb_for_stmt (phi) != bb)
3603 error ("bb_for_stmt (phi) is set to a wrong basic block");
3607 for (i = 0; i < phi_num_args; i++)
3609 tree t = PHI_ARG_DEF (phi, i);
3612 /* Addressable variables do have SSA_NAMEs but they
3613 are not considered gimple values. */
3614 if (TREE_CODE (t) != SSA_NAME
3615 && TREE_CODE (t) != FUNCTION_DECL
3616 && !is_gimple_val (t))
3618 error ("PHI def is not a GIMPLE value");
3619 debug_generic_stmt (phi);
3620 debug_generic_stmt (t);
3624 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3627 debug_generic_stmt (addr);
3631 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3634 error ("incorrect sharing of tree nodes");
3635 debug_generic_stmt (phi);
3636 debug_generic_stmt (addr);
3642 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3644 tree stmt = bsi_stmt (bsi);
3646 if (bb_for_stmt (stmt) != bb)
3648 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3653 err |= verify_stmt (stmt, bsi_end_p (bsi));
3654 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3657 error ("incorrect sharing of tree nodes");
3658 debug_generic_stmt (stmt);
3659 debug_generic_stmt (addr);
3666 internal_error ("verify_stmts failed");
3669 timevar_pop (TV_TREE_STMT_VERIFY);
3673 /* Verifies that the flow information is OK. */
3676 tree_verify_flow_info (void)
3680 block_stmt_iterator bsi;
3685 if (ENTRY_BLOCK_PTR->stmt_list)
3687 error ("ENTRY_BLOCK has a statement list associated with it");
3691 if (EXIT_BLOCK_PTR->stmt_list)
3693 error ("EXIT_BLOCK has a statement list associated with it");
3697 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3698 if (e->flags & EDGE_FALLTHRU)
3700 error ("fallthru to exit from bb %d", e->src->index);
3706 bool found_ctrl_stmt = false;
3710 /* Skip labels on the start of basic block. */
3711 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3713 tree prev_stmt = stmt;
3715 stmt = bsi_stmt (bsi);
3717 if (TREE_CODE (stmt) != LABEL_EXPR)
3720 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3722 error ("nonlocal label ");
3723 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3724 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3729 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3732 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3733 fprintf (stderr, " to block does not match in bb %d",
3738 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3739 != current_function_decl)
3742 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3743 fprintf (stderr, " has incorrect context in bb %d",
3749 /* Verify that body of basic block BB is free of control flow. */
3750 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3752 tree stmt = bsi_stmt (bsi);
3754 if (found_ctrl_stmt)
3756 error ("control flow in the middle of basic block %d",
3761 if (stmt_ends_bb_p (stmt))
3762 found_ctrl_stmt = true;
3764 if (TREE_CODE (stmt) == LABEL_EXPR)
3767 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3768 fprintf (stderr, " in the middle of basic block %d", bb->index);
3773 bsi = bsi_last (bb);
3774 if (bsi_end_p (bsi))
3777 stmt = bsi_stmt (bsi);
3779 err |= verify_eh_edges (stmt);
3781 if (is_ctrl_stmt (stmt))
3783 FOR_EACH_EDGE (e, ei, bb->succs)
3784 if (e->flags & EDGE_FALLTHRU)
3786 error ("fallthru edge after a control statement in bb %d",
3792 if (TREE_CODE (stmt) != COND_EXPR)
3794 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3795 after anything else but if statement. */
3796 FOR_EACH_EDGE (e, ei, bb->succs)
3797 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3799 error ("true/false edge after a non-COND_EXPR in bb %d",
3805 switch (TREE_CODE (stmt))
3811 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3812 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3814 error ("structured COND_EXPR at the end of bb %d", bb->index);
3818 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3820 if (!true_edge || !false_edge
3821 || !(true_edge->flags & EDGE_TRUE_VALUE)
3822 || !(false_edge->flags & EDGE_FALSE_VALUE)
3823 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3824 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3825 || EDGE_COUNT (bb->succs) >= 3)
3827 error ("wrong outgoing edge flags at end of bb %d",
3832 if (!has_label_p (true_edge->dest,
3833 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3835 error ("%<then%> label does not match edge at end of bb %d",
3840 if (!has_label_p (false_edge->dest,
3841 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3843 error ("%<else%> label does not match edge at end of bb %d",
3851 if (simple_goto_p (stmt))
3853 error ("explicit goto at end of bb %d", bb->index);
3858 /* FIXME. We should double check that the labels in the
3859 destination blocks have their address taken. */
3860 FOR_EACH_EDGE (e, ei, bb->succs)
3861 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3862 | EDGE_FALSE_VALUE))
3863 || !(e->flags & EDGE_ABNORMAL))
3865 error ("wrong outgoing edge flags at end of bb %d",
3873 if (!single_succ_p (bb)
3874 || (single_succ_edge (bb)->flags
3875 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3876 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3878 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3881 if (single_succ (bb) != EXIT_BLOCK_PTR)
3883 error ("return edge does not point to exit in bb %d",
3896 vec = SWITCH_LABELS (stmt);
3897 n = TREE_VEC_LENGTH (vec);
3899 /* Mark all the destination basic blocks. */
3900 for (i = 0; i < n; ++i)
3902 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3903 basic_block label_bb = label_to_block (lab);
3905 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3906 label_bb->aux = (void *)1;
3909 /* Verify that the case labels are sorted. */
3910 prev = TREE_VEC_ELT (vec, 0);
3911 for (i = 1; i < n - 1; ++i)
3913 tree c = TREE_VEC_ELT (vec, i);
3916 error ("found default case not at end of case vector");
3920 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3922 error ("case labels not sorted: ");
3923 print_generic_expr (stderr, prev, 0);
3924 fprintf (stderr," is greater than ");
3925 print_generic_expr (stderr, c, 0);
3926 fprintf (stderr," but comes before it.\n");
3931 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3933 error ("no default case found at end of case vector");
3937 FOR_EACH_EDGE (e, ei, bb->succs)
3941 error ("extra outgoing edge %d->%d",
3942 bb->index, e->dest->index);
3945 e->dest->aux = (void *)2;
3946 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3947 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3949 error ("wrong outgoing edge flags at end of bb %d",
3955 /* Check that we have all of them. */
3956 for (i = 0; i < n; ++i)
3958 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3959 basic_block label_bb = label_to_block (lab);
3961 if (label_bb->aux != (void *)2)
3963 error ("missing edge %i->%i",
3964 bb->index, label_bb->index);
3969 FOR_EACH_EDGE (e, ei, bb->succs)
3970 e->dest->aux = (void *)0;
3977 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3978 verify_dominators (CDI_DOMINATORS);
3984 /* Updates phi nodes after creating a forwarder block joined
3985 by edge FALLTHRU. */
3988 tree_make_forwarder_block (edge fallthru)
3992 basic_block dummy, bb;
3993 tree phi, new_phi, var;
3995 dummy = fallthru->src;
3996 bb = fallthru->dest;
3998 if (single_pred_p (bb))
4001 /* If we redirected a branch we must create new phi nodes at the
4003 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
4005 var = PHI_RESULT (phi);
4006 new_phi = create_phi_node (var, bb);
4007 SSA_NAME_DEF_STMT (var) = new_phi;
4008 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
4009 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
4012 /* Ensure that the PHI node chain is in the same order. */
4013 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
4015 /* Add the arguments we have stored on edges. */
4016 FOR_EACH_EDGE (e, ei, bb->preds)
4021 flush_pending_stmts (e);
4026 /* Return a non-special label in the head of basic block BLOCK.
4027 Create one if it doesn't exist. */
4030 tree_block_label (basic_block bb)
4032 block_stmt_iterator i, s = bsi_start (bb);
4036 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4038 stmt = bsi_stmt (i);
4039 if (TREE_CODE (stmt) != LABEL_EXPR)
4041 label = LABEL_EXPR_LABEL (stmt);
4042 if (!DECL_NONLOCAL (label))
4045 bsi_move_before (&i, &s);
4050 label = create_artificial_label ();
4051 stmt = build1 (LABEL_EXPR, void_type_node, label);
4052 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4057 /* Attempt to perform edge redirection by replacing a possibly complex
4058 jump instruction by a goto or by removing the jump completely.
4059 This can apply only if all edges now point to the same block. The
4060 parameters and return values are equivalent to
4061 redirect_edge_and_branch. */
4064 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4066 basic_block src = e->src;
4067 block_stmt_iterator b;
4070 /* We can replace or remove a complex jump only when we have exactly
4072 if (EDGE_COUNT (src->succs) != 2
4073 /* Verify that all targets will be TARGET. Specifically, the
4074 edge that is not E must also go to TARGET. */
4075 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4081 stmt = bsi_stmt (b);
4083 if (TREE_CODE (stmt) == COND_EXPR
4084 || TREE_CODE (stmt) == SWITCH_EXPR)
4086 bsi_remove (&b, true);
4087 e = ssa_redirect_edge (e, target);
4088 e->flags = EDGE_FALLTHRU;
4096 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4097 edge representing the redirected branch. */
4100 tree_redirect_edge_and_branch (edge e, basic_block dest)
4102 basic_block bb = e->src;
4103 block_stmt_iterator bsi;
4107 if (e->flags & EDGE_ABNORMAL)
4110 if (e->src != ENTRY_BLOCK_PTR
4111 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4114 if (e->dest == dest)
4117 label = tree_block_label (dest);
4119 bsi = bsi_last (bb);
4120 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4122 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4125 stmt = (e->flags & EDGE_TRUE_VALUE
4126 ? COND_EXPR_THEN (stmt)
4127 : COND_EXPR_ELSE (stmt));
4128 GOTO_DESTINATION (stmt) = label;
4132 /* No non-abnormal edges should lead from a non-simple goto, and
4133 simple ones should be represented implicitly. */
4138 tree cases = get_cases_for_edge (e, stmt);
4140 /* If we have a list of cases associated with E, then use it
4141 as it's a lot faster than walking the entire case vector. */
4144 edge e2 = find_edge (e->src, dest);
4151 CASE_LABEL (cases) = label;
4152 cases = TREE_CHAIN (cases);
4155 /* If there was already an edge in the CFG, then we need
4156 to move all the cases associated with E to E2. */
4159 tree cases2 = get_cases_for_edge (e2, stmt);
4161 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4162 TREE_CHAIN (cases2) = first;
4167 tree vec = SWITCH_LABELS (stmt);
4168 size_t i, n = TREE_VEC_LENGTH (vec);
4170 for (i = 0; i < n; i++)
4172 tree elt = TREE_VEC_ELT (vec, i);
4174 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4175 CASE_LABEL (elt) = label;
4183 bsi_remove (&bsi, true);
4184 e->flags |= EDGE_FALLTHRU;
4188 /* Otherwise it must be a fallthru edge, and we don't need to
4189 do anything besides redirecting it. */
4190 gcc_assert (e->flags & EDGE_FALLTHRU);
4194 /* Update/insert PHI nodes as necessary. */
4196 /* Now update the edges in the CFG. */
4197 e = ssa_redirect_edge (e, dest);
4203 /* Simple wrapper, as we can always redirect fallthru edges. */
4206 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4208 e = tree_redirect_edge_and_branch (e, dest);
4215 /* Splits basic block BB after statement STMT (but at least after the
4216 labels). If STMT is NULL, BB is split just after the labels. */
4219 tree_split_block (basic_block bb, void *stmt)
4221 block_stmt_iterator bsi;
4222 tree_stmt_iterator tsi_tgt;
4228 new_bb = create_empty_bb (bb);
4230 /* Redirect the outgoing edges. */
4231 new_bb->succs = bb->succs;
4233 FOR_EACH_EDGE (e, ei, new_bb->succs)
4236 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4239 /* Move everything from BSI to the new basic block. */
4240 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4242 act = bsi_stmt (bsi);
4243 if (TREE_CODE (act) == LABEL_EXPR)
4256 if (bsi_end_p (bsi))
4259 /* Split the statement list - avoid re-creating new containers as this
4260 brings ugly quadratic memory consumption in the inliner.
4261 (We are still quadratic since we need to update stmt BB pointers,
4263 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4264 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4265 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4266 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4272 /* Moves basic block BB after block AFTER. */
4275 tree_move_block_after (basic_block bb, basic_block after)
4277 if (bb->prev_bb == after)
4281 link_block (bb, after);
4287 /* Return true if basic_block can be duplicated. */
4290 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4296 /* Create a duplicate of the basic block BB. NOTE: This does not
4297 preserve SSA form. */
4300 tree_duplicate_bb (basic_block bb)
4303 block_stmt_iterator bsi, bsi_tgt;
4306 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4308 /* Copy the PHI nodes. We ignore PHI node arguments here because
4309 the incoming edges have not been setup yet. */
4310 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4312 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4313 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4316 /* Keep the chain of PHI nodes in the same order so that they can be
4317 updated by ssa_redirect_edge. */
4318 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4320 bsi_tgt = bsi_start (new_bb);
4321 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4323 def_operand_p def_p;
4324 ssa_op_iter op_iter;
4328 stmt = bsi_stmt (bsi);
4329 if (TREE_CODE (stmt) == LABEL_EXPR)
4332 /* Create a new copy of STMT and duplicate STMT's virtual
4334 copy = unshare_expr (stmt);
4335 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4336 copy_virtual_operands (copy, stmt);
4337 region = lookup_stmt_eh_region (stmt);
4339 add_stmt_to_eh_region (copy, region);
4341 /* Create new names for all the definitions created by COPY and
4342 add replacement mappings for each new name. */
4343 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4344 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4351 /* Basic block BB_COPY was created by code duplication. Add phi node
4352 arguments for edges going out of BB_COPY. The blocks that were
4353 duplicated have BB_DUPLICATED set. */
4356 add_phi_args_after_copy_bb (basic_block bb_copy)
4358 basic_block bb, dest;
4361 tree phi, phi_copy, phi_next, def;
4363 bb = get_bb_original (bb_copy);
4365 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4367 if (!phi_nodes (e_copy->dest))
4370 if (e_copy->dest->flags & BB_DUPLICATED)
4371 dest = get_bb_original (e_copy->dest);
4373 dest = e_copy->dest;
4375 e = find_edge (bb, dest);
4378 /* During loop unrolling the target of the latch edge is copied.
4379 In this case we are not looking for edge to dest, but to
4380 duplicated block whose original was dest. */
4381 FOR_EACH_EDGE (e, ei, bb->succs)
4382 if ((e->dest->flags & BB_DUPLICATED)
4383 && get_bb_original (e->dest) == dest)
4386 gcc_assert (e != NULL);
4389 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4391 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4393 phi_next = PHI_CHAIN (phi);
4394 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4395 add_phi_arg (phi_copy, def, e_copy);
4400 /* Blocks in REGION_COPY array of length N_REGION were created by
4401 duplication of basic blocks. Add phi node arguments for edges
4402 going from these blocks. */
4405 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4409 for (i = 0; i < n_region; i++)
4410 region_copy[i]->flags |= BB_DUPLICATED;
4412 for (i = 0; i < n_region; i++)
4413 add_phi_args_after_copy_bb (region_copy[i]);
4415 for (i = 0; i < n_region; i++)
4416 region_copy[i]->flags &= ~BB_DUPLICATED;
4419 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4420 important exit edge EXIT. By important we mean that no SSA name defined
4421 inside region is live over the other exit edges of the region. All entry
4422 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4423 to the duplicate of the region. SSA form, dominance and loop information
4424 is updated. The new basic blocks are stored to REGION_COPY in the same
4425 order as they had in REGION, provided that REGION_COPY is not NULL.
4426 The function returns false if it is unable to copy the region,
4430 tree_duplicate_sese_region (edge entry, edge exit,
4431 basic_block *region, unsigned n_region,
4432 basic_block *region_copy)
4435 bool free_region_copy = false, copying_header = false;
4436 struct loop *loop = entry->dest->loop_father;
4440 int total_freq = 0, entry_freq = 0;
4441 gcov_type total_count = 0, entry_count = 0;
4443 if (!can_copy_bbs_p (region, n_region))
4446 /* Some sanity checking. Note that we do not check for all possible
4447 missuses of the functions. I.e. if you ask to copy something weird,
4448 it will work, but the state of structures probably will not be
4450 for (i = 0; i < n_region; i++)
4452 /* We do not handle subloops, i.e. all the blocks must belong to the
4454 if (region[i]->loop_father != loop)
4457 if (region[i] != entry->dest
4458 && region[i] == loop->header)
4464 /* In case the function is used for loop header copying (which is the primary
4465 use), ensure that EXIT and its copy will be new latch and entry edges. */
4466 if (loop->header == entry->dest)
4468 copying_header = true;
4469 loop->copy = loop->outer;
4471 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4474 for (i = 0; i < n_region; i++)
4475 if (region[i] != exit->src
4476 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4482 region_copy = XNEWVEC (basic_block, n_region);
4483 free_region_copy = true;
4486 gcc_assert (!need_ssa_update_p ());
4488 /* Record blocks outside the region that are dominated by something
4490 doms = XNEWVEC (basic_block, n_basic_blocks);
4491 initialize_original_copy_tables ();
4493 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4495 if (entry->dest->count)
4497 total_count = entry->dest->count;
4498 entry_count = entry->count;
4499 /* Fix up corner cases, to avoid division by zero or creation of negative
4501 if (entry_count > total_count)
4502 entry_count = total_count;
4506 total_freq = entry->dest->frequency;
4507 entry_freq = EDGE_FREQUENCY (entry);
4508 /* Fix up corner cases, to avoid division by zero or creation of negative
4510 if (total_freq == 0)
4512 else if (entry_freq > total_freq)
4513 entry_freq = total_freq;
4516 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4517 split_edge_bb_loc (entry));
4520 scale_bbs_frequencies_gcov_type (region, n_region,
4521 total_count - entry_count,
4523 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4528 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4530 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4535 loop->header = exit->dest;
4536 loop->latch = exit->src;
4539 /* Redirect the entry and add the phi node arguments. */
4540 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4541 gcc_assert (redirected != NULL);
4542 flush_pending_stmts (entry);
4544 /* Concerning updating of dominators: We must recount dominators
4545 for entry block and its copy. Anything that is outside of the
4546 region, but was dominated by something inside needs recounting as
4548 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4549 doms[n_doms++] = get_bb_original (entry->dest);
4550 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4553 /* Add the other PHI node arguments. */
4554 add_phi_args_after_copy (region_copy, n_region);
4556 /* Update the SSA web. */
4557 update_ssa (TODO_update_ssa);
4559 if (free_region_copy)
4562 free_original_copy_tables ();
4567 DEF_VEC_P(basic_block);
4568 DEF_VEC_ALLOC_P(basic_block,heap);
4571 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4572 adding blocks when the dominator traversal reaches EXIT. This
4573 function silently assumes that ENTRY strictly dominates EXIT. */
4576 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4577 VEC(basic_block,heap) **bbs_p)
4581 for (son = first_dom_son (CDI_DOMINATORS, entry);
4583 son = next_dom_son (CDI_DOMINATORS, son))
4585 VEC_safe_push (basic_block, heap, *bbs_p, son);
4587 gather_blocks_in_sese_region (son, exit, bbs_p);
4597 bitmap vars_to_remove;
4598 htab_t new_label_map;
4602 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4603 contained in *TP and change the DECL_CONTEXT of every local
4604 variable referenced in *TP. */
4607 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4609 struct move_stmt_d *p = (struct move_stmt_d *) data;
4612 if (p->block && IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t))))
4613 TREE_BLOCK (t) = p->block;
4615 if (OMP_DIRECTIVE_P (t)
4616 && TREE_CODE (t) != OMP_RETURN
4617 && TREE_CODE (t) != OMP_CONTINUE)
4619 /* Do not remap variables inside OMP directives. Variables
4620 referenced in clauses and directive header belong to the
4621 parent function and should not be moved into the child
4623 bool save_remap_decls_p = p->remap_decls_p;
4624 p->remap_decls_p = false;
4627 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4629 p->remap_decls_p = save_remap_decls_p;
4631 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4633 if (TREE_CODE (t) == LABEL_DECL)
4635 if (p->new_label_map)
4637 struct tree_map in, *out;
4639 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4644 DECL_CONTEXT (t) = p->to_context;
4646 else if (p->remap_decls_p)
4648 DECL_CONTEXT (t) = p->to_context;
4650 if (TREE_CODE (t) == VAR_DECL)
4652 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4653 f->unexpanded_var_list
4654 = tree_cons (0, t, f->unexpanded_var_list);
4656 /* Mark T to be removed from the original function,
4657 otherwise it will be given a DECL_RTL when the
4658 original function is expanded. */
4659 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4663 else if (TYPE_P (t))
4670 /* Move basic block BB from function CFUN to function DEST_FN. The
4671 block is moved out of the original linked list and placed after
4672 block AFTER in the new list. Also, the block is removed from the
4673 original array of blocks and placed in DEST_FN's array of blocks.
4674 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4675 updated to reflect the moved edges.
4677 On exit, local variables that need to be removed from
4678 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4681 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4682 basic_block after, bool update_edge_count_p,
4683 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4685 struct control_flow_graph *cfg;
4688 block_stmt_iterator si;
4689 struct move_stmt_d d;
4690 unsigned old_len, new_len;
4693 /* Link BB to the new linked list. */
4694 move_block_after (bb, after);
4696 /* Update the edge count in the corresponding flowgraphs. */
4697 if (update_edge_count_p)
4698 FOR_EACH_EDGE (e, ei, bb->succs)
4700 cfun->cfg->x_n_edges--;
4701 dest_cfun->cfg->x_n_edges++;
4704 /* Remove BB from the original basic block array. */
4705 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4706 cfun->cfg->x_n_basic_blocks--;
4708 /* Grow DEST_CFUN's basic block array if needed. */
4709 cfg = dest_cfun->cfg;
4710 cfg->x_n_basic_blocks++;
4711 if (bb->index > cfg->x_last_basic_block)
4712 cfg->x_last_basic_block = bb->index;
4714 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4715 if ((unsigned) cfg->x_last_basic_block >= old_len)
4717 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4718 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4719 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4720 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4723 VEC_replace (basic_block, cfg->x_basic_block_info,
4724 cfg->x_last_basic_block, bb);
4726 /* The statements in BB need to be associated with a new TREE_BLOCK.
4727 Labels need to be associated with a new label-to-block map. */
4728 memset (&d, 0, sizeof (d));
4729 d.vars_to_remove = vars_to_remove;
4731 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4733 tree stmt = bsi_stmt (si);
4736 d.from_context = cfun->decl;
4737 d.to_context = dest_cfun->decl;
4738 d.remap_decls_p = true;
4739 d.new_label_map = new_label_map;
4740 if (TREE_BLOCK (stmt))
4741 d.block = DECL_INITIAL (dest_cfun->decl);
4743 walk_tree (&stmt, move_stmt_r, &d, NULL);
4745 if (TREE_CODE (stmt) == LABEL_EXPR)
4747 tree label = LABEL_EXPR_LABEL (stmt);
4748 int uid = LABEL_DECL_UID (label);
4750 gcc_assert (uid > -1);
4752 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4753 if (old_len <= (unsigned) uid)
4755 new_len = 3 * uid / 2;
4756 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4758 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4759 memset (&addr[old_len], 0,
4760 sizeof (basic_block) * (new_len - old_len));
4763 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4764 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4766 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4768 if (uid >= dest_cfun->last_label_uid)
4769 dest_cfun->last_label_uid = uid + 1;
4771 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4772 TREE_OPERAND (stmt, 0) =
4773 build_int_cst (NULL_TREE,
4774 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4777 region = lookup_stmt_eh_region (stmt);
4780 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4781 remove_stmt_from_eh_region (stmt);
4786 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4787 the outermost EH region. Use REGION as the incoming base EH region. */
4790 find_outermost_region_in_block (struct function *src_cfun,
4791 basic_block bb, int region)
4793 block_stmt_iterator si;
4795 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4797 tree stmt = bsi_stmt (si);
4800 if (TREE_CODE (stmt) == RESX_EXPR)
4801 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4803 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4804 if (stmt_region > 0)
4807 region = stmt_region;
4808 else if (stmt_region != region)
4810 region = eh_region_outermost (src_cfun, stmt_region, region);
4811 gcc_assert (region != -1);
4820 new_label_mapper (tree decl, void *data)
4822 htab_t hash = (htab_t) data;
4826 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4828 m = xmalloc (sizeof (struct tree_map));
4829 m->hash = DECL_UID (decl);
4831 m->to = create_artificial_label ();
4832 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4834 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4835 gcc_assert (*slot == NULL);
4842 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4843 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4844 single basic block in the original CFG and the new basic block is
4845 returned. DEST_CFUN must not have a CFG yet.
4847 Note that the region need not be a pure SESE region. Blocks inside
4848 the region may contain calls to abort/exit. The only restriction
4849 is that ENTRY_BB should be the only entry point and it must
4852 All local variables referenced in the region are assumed to be in
4853 the corresponding BLOCK_VARS and unexpanded variable lists
4854 associated with DEST_CFUN. */
4857 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4858 basic_block exit_bb)
4860 VEC(basic_block,heap) *bbs;
4861 basic_block after, bb, *entry_pred, *exit_succ;
4862 struct function *saved_cfun;
4863 int *entry_flag, *exit_flag, eh_offset;
4864 unsigned i, num_entry_edges, num_exit_edges;
4867 bitmap vars_to_remove;
4868 htab_t new_label_map;
4872 /* Collect all the blocks in the region. Manually add ENTRY_BB
4873 because it won't be added by dfs_enumerate_from. */
4874 calculate_dominance_info (CDI_DOMINATORS);
4876 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4878 gcc_assert (entry_bb != exit_bb
4880 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4883 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4884 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4886 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4887 the predecessor edges to ENTRY_BB and the successor edges to
4888 EXIT_BB so that we can re-attach them to the new basic block that
4889 will replace the region. */
4890 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4891 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4892 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4894 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4896 entry_flag[i] = e->flags;
4897 entry_pred[i++] = e->src;
4903 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4904 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4905 sizeof (basic_block));
4906 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4908 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4910 exit_flag[i] = e->flags;
4911 exit_succ[i++] = e->dest;
4922 /* Switch context to the child function to initialize DEST_FN's CFG. */
4923 gcc_assert (dest_cfun->cfg == NULL);
4926 init_empty_tree_cfg ();
4928 /* Initialize EH information for the new function. */
4930 new_label_map = NULL;
4935 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4936 region = find_outermost_region_in_block (saved_cfun, bb, region);
4938 init_eh_for_function ();
4941 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4942 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4943 new_label_map, region, 0);
4949 /* Move blocks from BBS into DEST_CFUN. */
4950 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4951 after = dest_cfun->cfg->x_entry_block_ptr;
4952 vars_to_remove = BITMAP_ALLOC (NULL);
4953 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4955 /* No need to update edge counts on the last block. It has
4956 already been updated earlier when we detached the region from
4957 the original CFG. */
4958 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4959 new_label_map, eh_offset);
4964 htab_delete (new_label_map);
4966 /* Remove the variables marked in VARS_TO_REMOVE from
4967 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4968 DECL_RTL in the context of CFUN. */
4969 if (!bitmap_empty_p (vars_to_remove))
4973 for (p = &cfun->unexpanded_var_list; *p; )
4975 tree var = TREE_VALUE (*p);
4976 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4978 *p = TREE_CHAIN (*p);
4982 p = &TREE_CHAIN (*p);
4986 BITMAP_FREE (vars_to_remove);
4988 /* Rewire the entry and exit blocks. The successor to the entry
4989 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4990 the child function. Similarly, the predecessor of DEST_FN's
4991 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4992 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4993 various CFG manipulation function get to the right CFG.
4995 FIXME, this is silly. The CFG ought to become a parameter to
4998 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
5000 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
5003 /* Back in the original function, the SESE region has disappeared,
5004 create a new basic block in its place. */
5005 bb = create_empty_bb (entry_pred[0]);
5006 for (i = 0; i < num_entry_edges; i++)
5007 make_edge (entry_pred[i], bb, entry_flag[i]);
5009 for (i = 0; i < num_exit_edges; i++)
5010 make_edge (bb, exit_succ[i], exit_flag[i]);
5019 free_dominance_info (CDI_DOMINATORS);
5020 free_dominance_info (CDI_POST_DOMINATORS);
5021 VEC_free (basic_block, heap, bbs);
5027 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5030 dump_function_to_file (tree fn, FILE *file, int flags)
5032 tree arg, vars, var;
5033 bool ignore_topmost_bind = false, any_var = false;
5036 struct function *saved_cfun;
5038 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5040 arg = DECL_ARGUMENTS (fn);
5043 print_generic_expr (file, arg, dump_flags);
5044 if (TREE_CHAIN (arg))
5045 fprintf (file, ", ");
5046 arg = TREE_CHAIN (arg);
5048 fprintf (file, ")\n");
5050 if (flags & TDF_DETAILS)
5051 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5052 if (flags & TDF_RAW)
5054 dump_node (fn, TDF_SLIM | flags, file);
5058 /* Switch CFUN to point to FN. */
5060 cfun = DECL_STRUCT_FUNCTION (fn);
5062 /* When GIMPLE is lowered, the variables are no longer available in
5063 BIND_EXPRs, so display them separately. */
5064 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5066 ignore_topmost_bind = true;
5068 fprintf (file, "{\n");
5069 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5071 var = TREE_VALUE (vars);
5073 print_generic_decl (file, var, flags);
5074 fprintf (file, "\n");
5080 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5082 /* Make a CFG based dump. */
5083 check_bb_profile (ENTRY_BLOCK_PTR, file);
5084 if (!ignore_topmost_bind)
5085 fprintf (file, "{\n");
5087 if (any_var && n_basic_blocks)
5088 fprintf (file, "\n");
5091 dump_generic_bb (file, bb, 2, flags);
5093 fprintf (file, "}\n");
5094 check_bb_profile (EXIT_BLOCK_PTR, file);
5100 /* Make a tree based dump. */
5101 chain = DECL_SAVED_TREE (fn);
5103 if (chain && TREE_CODE (chain) == BIND_EXPR)
5105 if (ignore_topmost_bind)
5107 chain = BIND_EXPR_BODY (chain);
5115 if (!ignore_topmost_bind)
5116 fprintf (file, "{\n");
5121 fprintf (file, "\n");
5123 print_generic_stmt_indented (file, chain, flags, indent);
5124 if (ignore_topmost_bind)
5125 fprintf (file, "}\n");
5128 fprintf (file, "\n\n");
5135 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5138 debug_function (tree fn, int flags)
5140 dump_function_to_file (fn, stderr, flags);
5144 /* Pretty print of the loops intermediate representation. */
5145 static void print_loop (FILE *, struct loop *, int);
5146 static void print_pred_bbs (FILE *, basic_block bb);
5147 static void print_succ_bbs (FILE *, basic_block bb);
5150 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5153 print_pred_bbs (FILE *file, basic_block bb)
5158 FOR_EACH_EDGE (e, ei, bb->preds)
5159 fprintf (file, "bb_%d ", e->src->index);
5163 /* Print on FILE the indexes for the successors of basic_block BB. */
5166 print_succ_bbs (FILE *file, basic_block bb)
5171 FOR_EACH_EDGE (e, ei, bb->succs)
5172 fprintf (file, "bb_%d ", e->dest->index);
5176 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5179 print_loop (FILE *file, struct loop *loop, int indent)
5187 s_indent = (char *) alloca ((size_t) indent + 1);
5188 memset ((void *) s_indent, ' ', (size_t) indent);
5189 s_indent[indent] = '\0';
5191 /* Print the loop's header. */
5192 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5194 /* Print the loop's body. */
5195 fprintf (file, "%s{\n", s_indent);
5197 if (bb->loop_father == loop)
5199 /* Print the basic_block's header. */
5200 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5201 print_pred_bbs (file, bb);
5202 fprintf (file, "}, succs = {");
5203 print_succ_bbs (file, bb);
5204 fprintf (file, "})\n");
5206 /* Print the basic_block's body. */
5207 fprintf (file, "%s {\n", s_indent);
5208 tree_dump_bb (bb, file, indent + 4);
5209 fprintf (file, "%s }\n", s_indent);
5212 print_loop (file, loop->inner, indent + 2);
5213 fprintf (file, "%s}\n", s_indent);
5214 print_loop (file, loop->next, indent);
5218 /* Follow a CFG edge from the entry point of the program, and on entry
5219 of a loop, pretty print the loop structure on FILE. */
5222 print_loop_ir (FILE *file)
5226 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5227 if (bb && bb->loop_father)
5228 print_loop (file, bb->loop_father, 0);
5232 /* Debugging loops structure at tree level. */
5235 debug_loop_ir (void)
5237 print_loop_ir (stderr);
5241 /* Return true if BB ends with a call, possibly followed by some
5242 instructions that must stay with the call. Return false,
5246 tree_block_ends_with_call_p (basic_block bb)
5248 block_stmt_iterator bsi = bsi_last (bb);
5249 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5253 /* Return true if BB ends with a conditional branch. Return false,
5257 tree_block_ends_with_condjump_p (basic_block bb)
5259 tree stmt = last_stmt (bb);
5260 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5264 /* Return true if we need to add fake edge to exit at statement T.
5265 Helper function for tree_flow_call_edges_add. */
5268 need_fake_edge_p (tree t)
5272 /* NORETURN and LONGJMP calls already have an edge to exit.
5273 CONST and PURE calls do not need one.
5274 We don't currently check for CONST and PURE here, although
5275 it would be a good idea, because those attributes are
5276 figured out from the RTL in mark_constant_function, and
5277 the counter incrementation code from -fprofile-arcs
5278 leads to different results from -fbranch-probabilities. */
5279 call = get_call_expr_in (t);
5281 && !(call_expr_flags (call) & ECF_NORETURN))
5284 if (TREE_CODE (t) == ASM_EXPR
5285 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5292 /* Add fake edges to the function exit for any non constant and non
5293 noreturn calls, volatile inline assembly in the bitmap of blocks
5294 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5295 the number of blocks that were split.
5297 The goal is to expose cases in which entering a basic block does
5298 not imply that all subsequent instructions must be executed. */
5301 tree_flow_call_edges_add (sbitmap blocks)
5304 int blocks_split = 0;
5305 int last_bb = last_basic_block;
5306 bool check_last_block = false;
5308 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5312 check_last_block = true;
5314 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5316 /* In the last basic block, before epilogue generation, there will be
5317 a fallthru edge to EXIT. Special care is required if the last insn
5318 of the last basic block is a call because make_edge folds duplicate
5319 edges, which would result in the fallthru edge also being marked
5320 fake, which would result in the fallthru edge being removed by
5321 remove_fake_edges, which would result in an invalid CFG.
5323 Moreover, we can't elide the outgoing fake edge, since the block
5324 profiler needs to take this into account in order to solve the minimal
5325 spanning tree in the case that the call doesn't return.
5327 Handle this by adding a dummy instruction in a new last basic block. */
5328 if (check_last_block)
5330 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5331 block_stmt_iterator bsi = bsi_last (bb);
5333 if (!bsi_end_p (bsi))
5336 if (t && need_fake_edge_p (t))
5340 e = find_edge (bb, EXIT_BLOCK_PTR);
5343 bsi_insert_on_edge (e, build_empty_stmt ());
5344 bsi_commit_edge_inserts ();
5349 /* Now add fake edges to the function exit for any non constant
5350 calls since there is no way that we can determine if they will
5352 for (i = 0; i < last_bb; i++)
5354 basic_block bb = BASIC_BLOCK (i);
5355 block_stmt_iterator bsi;
5356 tree stmt, last_stmt;
5361 if (blocks && !TEST_BIT (blocks, i))
5364 bsi = bsi_last (bb);
5365 if (!bsi_end_p (bsi))
5367 last_stmt = bsi_stmt (bsi);
5370 stmt = bsi_stmt (bsi);
5371 if (need_fake_edge_p (stmt))
5374 /* The handling above of the final block before the
5375 epilogue should be enough to verify that there is
5376 no edge to the exit block in CFG already.
5377 Calling make_edge in such case would cause us to
5378 mark that edge as fake and remove it later. */
5379 #ifdef ENABLE_CHECKING
5380 if (stmt == last_stmt)
5382 e = find_edge (bb, EXIT_BLOCK_PTR);
5383 gcc_assert (e == NULL);
5387 /* Note that the following may create a new basic block
5388 and renumber the existing basic blocks. */
5389 if (stmt != last_stmt)
5391 e = split_block (bb, stmt);
5395 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5399 while (!bsi_end_p (bsi));
5404 verify_flow_info ();
5406 return blocks_split;
5409 /* Purge dead abnormal call edges from basic block BB. */
5412 tree_purge_dead_abnormal_call_edges (basic_block bb)
5414 bool changed = tree_purge_dead_eh_edges (bb);
5416 if (current_function_has_nonlocal_label)
5418 tree stmt = last_stmt (bb);
5422 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5423 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5425 if (e->flags & EDGE_ABNORMAL)
5434 /* See tree_purge_dead_eh_edges below. */
5436 free_dominance_info (CDI_DOMINATORS);
5442 /* Purge dead EH edges from basic block BB. */
5445 tree_purge_dead_eh_edges (basic_block bb)
5447 bool changed = false;
5450 tree stmt = last_stmt (bb);
5452 if (stmt && tree_can_throw_internal (stmt))
5455 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5457 if (e->flags & EDGE_EH)
5466 /* Removal of dead EH edges might change dominators of not
5467 just immediate successors. E.g. when bb1 is changed so that
5468 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5469 eh edges purged by this function in:
5481 idom(bb5) must be recomputed. For now just free the dominance
5484 free_dominance_info (CDI_DOMINATORS);
5490 tree_purge_all_dead_eh_edges (bitmap blocks)
5492 bool changed = false;
5496 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5498 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5504 /* This function is called whenever a new edge is created or
5508 tree_execute_on_growing_pred (edge e)
5510 basic_block bb = e->dest;
5513 reserve_phi_args_for_new_edge (bb);
5516 /* This function is called immediately before edge E is removed from
5517 the edge vector E->dest->preds. */
5520 tree_execute_on_shrinking_pred (edge e)
5522 if (phi_nodes (e->dest))
5523 remove_phi_args (e);
5526 /*---------------------------------------------------------------------------
5527 Helper functions for Loop versioning
5528 ---------------------------------------------------------------------------*/
5530 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5531 of 'first'. Both of them are dominated by 'new_head' basic block. When
5532 'new_head' was created by 'second's incoming edge it received phi arguments
5533 on the edge by split_edge(). Later, additional edge 'e' was created to
5534 connect 'new_head' and 'first'. Now this routine adds phi args on this
5535 additional edge 'e' that new_head to second edge received as part of edge
5540 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5541 basic_block new_head, edge e)
5544 edge e2 = find_edge (new_head, second);
5546 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5547 edge, we should always have an edge from NEW_HEAD to SECOND. */
5548 gcc_assert (e2 != NULL);
5550 /* Browse all 'second' basic block phi nodes and add phi args to
5551 edge 'e' for 'first' head. PHI args are always in correct order. */
5553 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5555 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5557 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5558 add_phi_arg (phi1, def, e);
5562 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5563 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5564 the destination of the ELSE part. */
5566 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5567 basic_block cond_bb, void *cond_e)
5569 block_stmt_iterator bsi;
5570 tree goto1 = NULL_TREE;
5571 tree goto2 = NULL_TREE;
5572 tree new_cond_expr = NULL_TREE;
5573 tree cond_expr = (tree) cond_e;
5576 /* Build new conditional expr */
5577 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5578 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5579 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5581 /* Add new cond in cond_bb. */
5582 bsi = bsi_start (cond_bb);
5583 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5584 /* Adjust edges appropriately to connect new head with first head
5585 as well as second head. */
5586 e0 = single_succ_edge (cond_bb);
5587 e0->flags &= ~EDGE_FALLTHRU;
5588 e0->flags |= EDGE_FALSE_VALUE;
5591 struct cfg_hooks tree_cfg_hooks = {
5593 tree_verify_flow_info,
5594 tree_dump_bb, /* dump_bb */
5595 create_bb, /* create_basic_block */
5596 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5597 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5598 remove_bb, /* delete_basic_block */
5599 tree_split_block, /* split_block */
5600 tree_move_block_after, /* move_block_after */
5601 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5602 tree_merge_blocks, /* merge_blocks */
5603 tree_predict_edge, /* predict_edge */
5604 tree_predicted_by_p, /* predicted_by_p */
5605 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5606 tree_duplicate_bb, /* duplicate_block */
5607 tree_split_edge, /* split_edge */
5608 tree_make_forwarder_block, /* make_forward_block */
5609 NULL, /* tidy_fallthru_edge */
5610 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5611 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5612 tree_flow_call_edges_add, /* flow_call_edges_add */
5613 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5614 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5615 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5616 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5617 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5618 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5619 flush_pending_stmts /* flush_pending_stmts */
5623 /* Split all critical edges. */
5626 split_critical_edges (void)
5632 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5633 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5634 mappings around the calls to split_edge. */
5635 start_recording_case_labels ();
5638 FOR_EACH_EDGE (e, ei, bb->succs)
5639 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5644 end_recording_case_labels ();
5648 struct tree_opt_pass pass_split_crit_edges =
5650 "crited", /* name */
5652 split_critical_edges, /* execute */
5655 0, /* static_pass_number */
5656 TV_TREE_SPLIT_EDGES, /* tv_id */
5657 PROP_cfg, /* properties required */
5658 PROP_no_crit_edges, /* properties_provided */
5659 0, /* properties_destroyed */
5660 0, /* todo_flags_start */
5661 TODO_dump_func, /* todo_flags_finish */
5666 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5667 a temporary, make sure and register it to be renamed if necessary,
5668 and finally return the temporary. Put the statements to compute
5669 EXP before the current statement in BSI. */
5672 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5674 tree t, new_stmt, orig_stmt;
5676 if (is_gimple_val (exp))
5679 t = make_rename_temp (type, NULL);
5680 new_stmt = build2 (MODIFY_EXPR, type, t, exp);
5682 orig_stmt = bsi_stmt (*bsi);
5683 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5684 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5686 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5688 mark_new_vars_to_rename (new_stmt);
5693 /* Build a ternary operation and gimplify it. Emit code before BSI.
5694 Return the gimple_val holding the result. */
5697 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5698 tree type, tree a, tree b, tree c)
5702 ret = fold_build3 (code, type, a, b, c);
5705 return gimplify_val (bsi, type, ret);
5708 /* Build a binary operation and gimplify it. Emit code before BSI.
5709 Return the gimple_val holding the result. */
5712 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5713 tree type, tree a, tree b)
5717 ret = fold_build2 (code, type, a, b);
5720 return gimplify_val (bsi, type, ret);
5723 /* Build a unary operation and gimplify it. Emit code before BSI.
5724 Return the gimple_val holding the result. */
5727 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5732 ret = fold_build1 (code, type, a);
5735 return gimplify_val (bsi, type, ret);
5740 /* Emit return warnings. */
5743 execute_warn_function_return (void)
5745 #ifdef USE_MAPPED_LOCATION
5746 source_location location;
5754 /* If we have a path to EXIT, then we do return. */
5755 if (TREE_THIS_VOLATILE (cfun->decl)
5756 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5758 #ifdef USE_MAPPED_LOCATION
5759 location = UNKNOWN_LOCATION;
5763 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5765 last = last_stmt (e->src);
5766 if (TREE_CODE (last) == RETURN_EXPR
5767 #ifdef USE_MAPPED_LOCATION
5768 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5770 && (locus = EXPR_LOCUS (last)) != NULL)
5774 #ifdef USE_MAPPED_LOCATION
5775 if (location == UNKNOWN_LOCATION)
5776 location = cfun->function_end_locus;
5777 warning (0, "%H%<noreturn%> function does return", &location);
5780 locus = &cfun->function_end_locus;
5781 warning (0, "%H%<noreturn%> function does return", locus);
5785 /* If we see "return;" in some basic block, then we do reach the end
5786 without returning a value. */
5787 else if (warn_return_type
5788 && !TREE_NO_WARNING (cfun->decl)
5789 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5790 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5792 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5794 tree last = last_stmt (e->src);
5795 if (TREE_CODE (last) == RETURN_EXPR
5796 && TREE_OPERAND (last, 0) == NULL
5797 && !TREE_NO_WARNING (last))
5799 #ifdef USE_MAPPED_LOCATION
5800 location = EXPR_LOCATION (last);
5801 if (location == UNKNOWN_LOCATION)
5802 location = cfun->function_end_locus;
5803 warning (0, "%Hcontrol reaches end of non-void function", &location);
5805 locus = EXPR_LOCUS (last);
5807 locus = &cfun->function_end_locus;
5808 warning (0, "%Hcontrol reaches end of non-void function", locus);
5810 TREE_NO_WARNING (cfun->decl) = 1;
5819 /* Given a basic block B which ends with a conditional and has
5820 precisely two successors, determine which of the edges is taken if
5821 the conditional is true and which is taken if the conditional is
5822 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5825 extract_true_false_edges_from_block (basic_block b,
5829 edge e = EDGE_SUCC (b, 0);
5831 if (e->flags & EDGE_TRUE_VALUE)
5834 *false_edge = EDGE_SUCC (b, 1);
5839 *true_edge = EDGE_SUCC (b, 1);
5843 struct tree_opt_pass pass_warn_function_return =
5847 execute_warn_function_return, /* execute */
5850 0, /* static_pass_number */
5852 PROP_cfg, /* properties_required */
5853 0, /* properties_provided */
5854 0, /* properties_destroyed */
5855 0, /* todo_flags_start */
5856 0, /* todo_flags_finish */
5860 /* Emit noreturn warnings. */
5863 execute_warn_function_noreturn (void)
5865 if (warn_missing_noreturn
5866 && !TREE_THIS_VOLATILE (cfun->decl)
5867 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5868 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5869 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5870 "for attribute %<noreturn%>",
5875 struct tree_opt_pass pass_warn_function_noreturn =
5879 execute_warn_function_noreturn, /* execute */
5882 0, /* static_pass_number */
5884 PROP_cfg, /* properties_required */
5885 0, /* properties_provided */
5886 0, /* properties_destroyed */
5887 0, /* todo_flags_start */
5888 0, /* todo_flags_finish */