1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
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"
49 #include "value-prof.h"
51 /* This file contains functions for building the Control Flow Graph (CFG)
52 for a function tree. */
54 /* Local declarations. */
56 /* Initial capacity for the basic block array. */
57 static const int initial_cfg_capacity = 20;
59 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
60 which use a particular edge. The CASE_LABEL_EXPRs are chained together
61 via their TREE_CHAIN field, which we clear after we're done with the
62 hash table to prevent problems with duplication of SWITCH_EXPRs.
64 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
65 update the case vector in response to edge redirections.
67 Right now this table is set up and torn down at key points in the
68 compilation process. It would be nice if we could make the table
69 more persistent. The key is getting notification of changes to
70 the CFG (particularly edge removal, creation and redirection). */
72 struct edge_to_cases_elt
74 /* The edge itself. Necessary for hashing and equality tests. */
77 /* The case labels associated with this edge. We link these up via
78 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
79 when we destroy the hash table. This prevents problems when copying
84 static htab_t edge_to_cases;
89 long num_merged_labels;
92 static struct cfg_stats_d cfg_stats;
94 /* Nonzero if we found a computed goto while building basic blocks. */
95 static bool found_computed_goto;
97 /* Basic blocks and flowgraphs. */
98 static basic_block create_bb (void *, void *, basic_block);
99 static void make_blocks (tree);
100 static void factor_computed_gotos (void);
103 static void make_edges (void);
104 static void make_cond_expr_edges (basic_block);
105 static void make_switch_expr_edges (basic_block);
106 static void make_goto_expr_edges (basic_block);
107 static edge tree_redirect_edge_and_branch (edge, basic_block);
108 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
109 static unsigned int split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree, tree);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge);
115 static void tree_cfg2vcg (FILE *);
116 static inline void change_bb_for_stmt (tree t, basic_block bb);
118 /* Flowgraph optimization and cleanup. */
119 static void tree_merge_blocks (basic_block, basic_block);
120 static bool tree_can_merge_blocks_p (basic_block, basic_block);
121 static void remove_bb (basic_block);
122 static edge find_taken_edge_computed_goto (basic_block, tree);
123 static edge find_taken_edge_cond_expr (basic_block, tree);
124 static edge find_taken_edge_switch_expr (basic_block, tree);
125 static tree find_case_label_for_value (tree, tree);
128 init_empty_tree_cfg (void)
130 /* Initialize the basic block array. */
132 profile_status = PROFILE_ABSENT;
133 n_basic_blocks = NUM_FIXED_BLOCKS;
134 last_basic_block = NUM_FIXED_BLOCKS;
135 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
136 VEC_safe_grow_cleared (basic_block, gc, basic_block_info,
137 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_cleared (basic_block, gc, label_to_block_map,
142 initial_cfg_capacity);
144 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
145 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
146 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
147 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
150 /*---------------------------------------------------------------------------
152 ---------------------------------------------------------------------------*/
154 /* Entry point to the CFG builder for trees. TP points to the list of
155 statements to be added to the flowgraph. */
158 build_tree_cfg (tree *tp)
160 /* Register specific tree functions. */
161 tree_register_cfg_hooks ();
163 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
165 init_empty_tree_cfg ();
167 found_computed_goto = 0;
170 /* Computed gotos are hell to deal with, especially if there are
171 lots of them with a large number of destinations. So we factor
172 them to a common computed goto location before we build the
173 edge list. After we convert back to normal form, we will un-factor
174 the computed gotos since factoring introduces an unwanted jump. */
175 if (found_computed_goto)
176 factor_computed_gotos ();
178 /* Make sure there is always at least one block, even if it's empty. */
179 if (n_basic_blocks == NUM_FIXED_BLOCKS)
180 create_empty_bb (ENTRY_BLOCK_PTR);
182 /* Adjust the size of the array. */
183 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
184 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, n_basic_blocks);
186 /* To speed up statement iterator walks, we first purge dead labels. */
187 cleanup_dead_labels ();
189 /* Group case nodes to reduce the number of edges.
190 We do this after cleaning up dead labels because otherwise we miss
191 a lot of obvious case merging opportunities. */
192 group_case_labels ();
194 /* Create the edges of the flowgraph. */
197 /* Debugging dumps. */
199 /* Write the flowgraph to a VCG file. */
201 int local_dump_flags;
202 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
205 tree_cfg2vcg (vcg_file);
206 dump_end (TDI_vcg, vcg_file);
210 #ifdef ENABLE_CHECKING
214 /* Dump a textual representation of the flowgraph. */
216 dump_tree_cfg (dump_file, dump_flags);
220 execute_build_cfg (void)
222 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
226 struct tree_opt_pass pass_build_cfg =
230 execute_build_cfg, /* execute */
233 0, /* static_pass_number */
234 TV_TREE_CFG, /* tv_id */
235 PROP_gimple_leh, /* properties_required */
236 PROP_cfg, /* properties_provided */
237 0, /* properties_destroyed */
238 0, /* todo_flags_start */
239 TODO_verify_stmts, /* todo_flags_finish */
243 /* Search the CFG for any computed gotos. If found, factor them to a
244 common computed goto site. Also record the location of that site so
245 that we can un-factor the gotos after we have converted back to
249 factor_computed_gotos (void)
252 tree factored_label_decl = NULL;
254 tree factored_computed_goto_label = NULL;
255 tree factored_computed_goto = NULL;
257 /* We know there are one or more computed gotos in this function.
258 Examine the last statement in each basic block to see if the block
259 ends with a computed goto. */
263 block_stmt_iterator bsi = bsi_last (bb);
268 last = bsi_stmt (bsi);
270 /* Ignore the computed goto we create when we factor the original
272 if (last == factored_computed_goto)
275 /* If the last statement is a computed goto, factor it. */
276 if (computed_goto_p (last))
280 /* The first time we find a computed goto we need to create
281 the factored goto block and the variable each original
282 computed goto will use for their goto destination. */
283 if (! factored_computed_goto)
285 basic_block new_bb = create_empty_bb (bb);
286 block_stmt_iterator new_bsi = bsi_start (new_bb);
288 /* Create the destination of the factored goto. Each original
289 computed goto will put its desired destination into this
290 variable and jump to the label we create immediately
292 var = create_tmp_var (ptr_type_node, "gotovar");
294 /* Build a label for the new block which will contain the
295 factored computed goto. */
296 factored_label_decl = create_artificial_label ();
297 factored_computed_goto_label
298 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
299 bsi_insert_after (&new_bsi, factored_computed_goto_label,
302 /* Build our new computed goto. */
303 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
304 bsi_insert_after (&new_bsi, factored_computed_goto,
308 /* Copy the original computed goto's destination into VAR. */
309 assignment = build2_gimple (GIMPLE_MODIFY_STMT,
310 var, GOTO_DESTINATION (last));
311 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
313 /* And re-vector the computed goto to the new destination. */
314 GOTO_DESTINATION (last) = factored_label_decl;
320 /* Build a flowgraph for the statement_list STMT_LIST. */
323 make_blocks (tree stmt_list)
325 tree_stmt_iterator i = tsi_start (stmt_list);
327 bool start_new_block = true;
328 bool first_stmt_of_list = true;
329 basic_block bb = ENTRY_BLOCK_PTR;
331 while (!tsi_end_p (i))
338 /* If the statement starts a new basic block or if we have determined
339 in a previous pass that we need to create a new block for STMT, do
341 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
343 if (!first_stmt_of_list)
344 stmt_list = tsi_split_statement_list_before (&i);
345 bb = create_basic_block (stmt_list, NULL, bb);
346 start_new_block = false;
349 /* Now add STMT to BB and create the subgraphs for special statement
351 set_bb_for_stmt (stmt, bb);
353 if (computed_goto_p (stmt))
354 found_computed_goto = true;
356 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
358 if (stmt_ends_bb_p (stmt))
359 start_new_block = true;
362 first_stmt_of_list = false;
367 /* Create and return a new empty basic block after bb AFTER. */
370 create_bb (void *h, void *e, basic_block after)
376 /* Create and initialize a new basic block. Since alloc_block uses
377 ggc_alloc_cleared to allocate a basic block, we do not have to
378 clear the newly allocated basic block here. */
381 bb->index = last_basic_block;
383 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
385 /* Add the new block to the linked list of blocks. */
386 link_block (bb, after);
388 /* Grow the basic block array if needed. */
389 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
391 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
392 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
395 /* Add the newly created block to the array. */
396 SET_BASIC_BLOCK (last_basic_block, bb);
405 /*---------------------------------------------------------------------------
407 ---------------------------------------------------------------------------*/
409 /* Fold COND_EXPR_COND of each COND_EXPR. */
412 fold_cond_expr_cond (void)
418 tree stmt = last_stmt (bb);
421 && TREE_CODE (stmt) == COND_EXPR)
423 tree cond = fold (COND_EXPR_COND (stmt));
424 if (integer_zerop (cond))
425 COND_EXPR_COND (stmt) = boolean_false_node;
426 else if (integer_onep (cond))
427 COND_EXPR_COND (stmt) = boolean_true_node;
432 /* Join all the blocks in the flowgraph. */
438 struct omp_region *cur_region = NULL;
440 /* Create an edge from entry to the first block with executable
442 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
444 /* Traverse the basic block array placing edges. */
447 tree last = last_stmt (bb);
452 enum tree_code code = TREE_CODE (last);
456 make_goto_expr_edges (bb);
460 make_edge (bb, EXIT_BLOCK_PTR, 0);
464 make_cond_expr_edges (bb);
468 make_switch_expr_edges (bb);
472 make_eh_edges (last);
477 /* If this function receives a nonlocal goto, then we need to
478 make edges from this call site to all the nonlocal goto
480 if (tree_can_make_abnormal_goto (last))
481 make_abnormal_goto_edges (bb, true);
483 /* If this statement has reachable exception handlers, then
484 create abnormal edges to them. */
485 make_eh_edges (last);
487 /* Some calls are known not to return. */
488 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
494 case GIMPLE_MODIFY_STMT:
495 if (is_ctrl_altering_stmt (last))
497 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
498 the CALL_EXPR may have an abnormal edge. Search the RHS
499 for this case and create any required edges. */
500 if (tree_can_make_abnormal_goto (last))
501 make_abnormal_goto_edges (bb, true);
503 make_eh_edges (last);
515 cur_region = new_omp_region (bb, code, cur_region);
520 cur_region = new_omp_region (bb, code, cur_region);
525 /* In the case of an OMP_SECTION, the edge will go somewhere
526 other than the next block. This will be created later. */
527 cur_region->exit = bb;
528 fallthru = cur_region->type != OMP_SECTION;
529 cur_region = cur_region->outer;
533 cur_region->cont = bb;
534 switch (cur_region->type)
537 /* ??? Technically there should be a some sort of loopback
538 edge here, but it goes to a block that doesn't exist yet,
539 and without it, updating the ssa form would be a real
540 bear. Fortunately, we don't yet do ssa before expanding
545 /* Wire up the edges into and out of the nested sections. */
546 /* ??? Similarly wrt loopback. */
548 struct omp_region *i;
549 for (i = cur_region->inner; i ; i = i->next)
551 gcc_assert (i->type == OMP_SECTION);
552 make_edge (cur_region->entry, i->entry, 0);
553 make_edge (i->exit, bb, EDGE_FALLTHRU);
565 gcc_assert (!stmt_ends_bb_p (last));
573 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
579 /* Fold COND_EXPR_COND of each COND_EXPR. */
580 fold_cond_expr_cond ();
582 /* Clean up the graph and warn for unreachable code. */
587 /* Create the edges for a COND_EXPR starting at block BB.
588 At this point, both clauses must contain only simple gotos. */
591 make_cond_expr_edges (basic_block bb)
593 tree entry = last_stmt (bb);
594 basic_block then_bb, else_bb;
595 tree then_label, else_label;
599 gcc_assert (TREE_CODE (entry) == COND_EXPR);
601 /* Entry basic blocks for each component. */
602 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
603 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
604 then_bb = label_to_block (then_label);
605 else_bb = label_to_block (else_label);
607 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
608 #ifdef USE_MAPPED_LOCATION
609 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
611 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
613 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
616 #ifdef USE_MAPPED_LOCATION
617 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
619 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
624 /* Hashing routine for EDGE_TO_CASES. */
627 edge_to_cases_hash (const void *p)
629 edge e = ((struct edge_to_cases_elt *)p)->e;
631 /* Hash on the edge itself (which is a pointer). */
632 return htab_hash_pointer (e);
635 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
636 for equality is just a pointer comparison. */
639 edge_to_cases_eq (const void *p1, const void *p2)
641 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
642 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
647 /* Called for each element in the hash table (P) as we delete the
648 edge to cases hash table.
650 Clear all the TREE_CHAINs to prevent problems with copying of
651 SWITCH_EXPRs and structure sharing rules, then free the hash table
655 edge_to_cases_cleanup (void *p)
657 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
660 for (t = elt->case_labels; t; t = next)
662 next = TREE_CHAIN (t);
663 TREE_CHAIN (t) = NULL;
668 /* Start recording information mapping edges to case labels. */
671 start_recording_case_labels (void)
673 gcc_assert (edge_to_cases == NULL);
675 edge_to_cases = htab_create (37,
678 edge_to_cases_cleanup);
681 /* Return nonzero if we are recording information for case labels. */
684 recording_case_labels_p (void)
686 return (edge_to_cases != NULL);
689 /* Stop recording information mapping edges to case labels and
690 remove any information we have recorded. */
692 end_recording_case_labels (void)
694 htab_delete (edge_to_cases);
695 edge_to_cases = NULL;
698 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
701 record_switch_edge (edge e, tree case_label)
703 struct edge_to_cases_elt *elt;
706 /* Build a hash table element so we can see if E is already
708 elt = XNEW (struct edge_to_cases_elt);
710 elt->case_labels = case_label;
712 slot = htab_find_slot (edge_to_cases, elt, INSERT);
716 /* E was not in the hash table. Install E into the hash table. */
721 /* E was already in the hash table. Free ELT as we do not need it
725 /* Get the entry stored in the hash table. */
726 elt = (struct edge_to_cases_elt *) *slot;
728 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
729 TREE_CHAIN (case_label) = elt->case_labels;
730 elt->case_labels = case_label;
734 /* If we are inside a {start,end}_recording_cases block, then return
735 a chain of CASE_LABEL_EXPRs from T which reference E.
737 Otherwise return NULL. */
740 get_cases_for_edge (edge e, tree t)
742 struct edge_to_cases_elt elt, *elt_p;
747 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
748 chains available. Return NULL so the caller can detect this case. */
749 if (!recording_case_labels_p ())
754 elt.case_labels = NULL;
755 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
759 elt_p = (struct edge_to_cases_elt *)*slot;
760 return elt_p->case_labels;
763 /* If we did not find E in the hash table, then this must be the first
764 time we have been queried for information about E & T. Add all the
765 elements from T to the hash table then perform the query again. */
767 vec = SWITCH_LABELS (t);
768 n = TREE_VEC_LENGTH (vec);
769 for (i = 0; i < n; i++)
771 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
772 basic_block label_bb = label_to_block (lab);
773 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
778 /* Create the edges for a SWITCH_EXPR starting at block BB.
779 At this point, the switch body has been lowered and the
780 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
783 make_switch_expr_edges (basic_block bb)
785 tree entry = last_stmt (bb);
789 vec = SWITCH_LABELS (entry);
790 n = TREE_VEC_LENGTH (vec);
792 for (i = 0; i < n; ++i)
794 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
795 basic_block label_bb = label_to_block (lab);
796 make_edge (bb, label_bb, 0);
801 /* Return the basic block holding label DEST. */
804 label_to_block_fn (struct function *ifun, tree dest)
806 int uid = LABEL_DECL_UID (dest);
808 /* We would die hard when faced by an undefined label. Emit a label to
809 the very first basic block. This will hopefully make even the dataflow
810 and undefined variable warnings quite right. */
811 if ((errorcount || sorrycount) && uid < 0)
813 block_stmt_iterator bsi =
814 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
817 stmt = build1 (LABEL_EXPR, void_type_node, dest);
818 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
819 uid = LABEL_DECL_UID (dest);
821 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
822 <= (unsigned int) uid)
824 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
827 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
828 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
831 make_abnormal_goto_edges (basic_block bb, bool for_call)
833 basic_block target_bb;
834 block_stmt_iterator bsi;
836 FOR_EACH_BB (target_bb)
837 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
839 tree target = bsi_stmt (bsi);
841 if (TREE_CODE (target) != LABEL_EXPR)
844 target = LABEL_EXPR_LABEL (target);
846 /* Make an edge to every label block that has been marked as a
847 potential target for a computed goto or a non-local goto. */
848 if ((FORCED_LABEL (target) && !for_call)
849 || (DECL_NONLOCAL (target) && for_call))
851 make_edge (bb, target_bb, EDGE_ABNORMAL);
857 /* Create edges for a goto statement at block BB. */
860 make_goto_expr_edges (basic_block bb)
862 block_stmt_iterator last = bsi_last (bb);
863 tree goto_t = bsi_stmt (last);
865 /* A simple GOTO creates normal edges. */
866 if (simple_goto_p (goto_t))
868 tree dest = GOTO_DESTINATION (goto_t);
869 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
870 #ifdef USE_MAPPED_LOCATION
871 e->goto_locus = EXPR_LOCATION (goto_t);
873 e->goto_locus = EXPR_LOCUS (goto_t);
875 bsi_remove (&last, true);
879 /* A computed GOTO creates abnormal edges. */
880 make_abnormal_goto_edges (bb, false);
884 /*---------------------------------------------------------------------------
886 ---------------------------------------------------------------------------*/
888 /* Cleanup useless labels in basic blocks. This is something we wish
889 to do early because it allows us to group case labels before creating
890 the edges for the CFG, and it speeds up block statement iterators in
892 We only run this pass once, running it more than once is probably not
895 /* A map from basic block index to the leading label of that block. */
896 static tree *label_for_bb;
898 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
900 update_eh_label (struct eh_region *region)
902 tree old_label = get_eh_region_tree_label (region);
906 basic_block bb = label_to_block (old_label);
908 /* ??? After optimizing, there may be EH regions with labels
909 that have already been removed from the function body, so
910 there is no basic block for them. */
914 new_label = label_for_bb[bb->index];
915 set_eh_region_tree_label (region, new_label);
919 /* Given LABEL return the first label in the same basic block. */
921 main_block_label (tree label)
923 basic_block bb = label_to_block (label);
925 /* label_to_block possibly inserted undefined label into the chain. */
926 if (!label_for_bb[bb->index])
927 label_for_bb[bb->index] = label;
928 return label_for_bb[bb->index];
931 /* Cleanup redundant labels. This is a three-step process:
932 1) Find the leading label for each block.
933 2) Redirect all references to labels to the leading labels.
934 3) Cleanup all useless labels. */
937 cleanup_dead_labels (void)
940 label_for_bb = XCNEWVEC (tree, last_basic_block);
942 /* Find a suitable label for each block. We use the first user-defined
943 label if there is one, or otherwise just the first label we see. */
946 block_stmt_iterator i;
948 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
950 tree label, stmt = bsi_stmt (i);
952 if (TREE_CODE (stmt) != LABEL_EXPR)
955 label = LABEL_EXPR_LABEL (stmt);
957 /* If we have not yet seen a label for the current block,
958 remember this one and see if there are more labels. */
959 if (! label_for_bb[bb->index])
961 label_for_bb[bb->index] = label;
965 /* If we did see a label for the current block already, but it
966 is an artificially created label, replace it if the current
967 label is a user defined label. */
968 if (! DECL_ARTIFICIAL (label)
969 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
971 label_for_bb[bb->index] = label;
977 /* Now redirect all jumps/branches to the selected label.
978 First do so for each block ending in a control statement. */
981 tree stmt = last_stmt (bb);
985 switch (TREE_CODE (stmt))
989 tree true_branch, false_branch;
991 true_branch = COND_EXPR_THEN (stmt);
992 false_branch = COND_EXPR_ELSE (stmt);
994 GOTO_DESTINATION (true_branch)
995 = main_block_label (GOTO_DESTINATION (true_branch));
996 GOTO_DESTINATION (false_branch)
997 = main_block_label (GOTO_DESTINATION (false_branch));
1005 tree vec = SWITCH_LABELS (stmt);
1006 size_t n = TREE_VEC_LENGTH (vec);
1008 /* Replace all destination labels. */
1009 for (i = 0; i < n; ++i)
1011 tree elt = TREE_VEC_ELT (vec, i);
1012 tree label = main_block_label (CASE_LABEL (elt));
1013 CASE_LABEL (elt) = label;
1018 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1019 remove them until after we've created the CFG edges. */
1021 if (! computed_goto_p (stmt))
1023 GOTO_DESTINATION (stmt)
1024 = main_block_label (GOTO_DESTINATION (stmt));
1033 for_each_eh_region (update_eh_label);
1035 /* Finally, purge dead labels. All user-defined labels and labels that
1036 can be the target of non-local gotos and labels which have their
1037 address taken are preserved. */
1040 block_stmt_iterator i;
1041 tree label_for_this_bb = label_for_bb[bb->index];
1043 if (! label_for_this_bb)
1046 for (i = bsi_start (bb); !bsi_end_p (i); )
1048 tree label, stmt = bsi_stmt (i);
1050 if (TREE_CODE (stmt) != LABEL_EXPR)
1053 label = LABEL_EXPR_LABEL (stmt);
1055 if (label == label_for_this_bb
1056 || ! DECL_ARTIFICIAL (label)
1057 || DECL_NONLOCAL (label)
1058 || FORCED_LABEL (label))
1061 bsi_remove (&i, true);
1065 free (label_for_bb);
1068 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1069 and scan the sorted vector of cases. Combine the ones jumping to the
1071 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1074 group_case_labels (void)
1080 tree stmt = last_stmt (bb);
1081 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1083 tree labels = SWITCH_LABELS (stmt);
1084 int old_size = TREE_VEC_LENGTH (labels);
1085 int i, j, new_size = old_size;
1086 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1089 /* The default label is always the last case in a switch
1090 statement after gimplification. */
1091 default_label = CASE_LABEL (default_case);
1093 /* Look for possible opportunities to merge cases.
1094 Ignore the last element of the label vector because it
1095 must be the default case. */
1097 while (i < old_size - 1)
1099 tree base_case, base_label, base_high;
1100 base_case = TREE_VEC_ELT (labels, i);
1102 gcc_assert (base_case);
1103 base_label = CASE_LABEL (base_case);
1105 /* Discard cases that have the same destination as the
1107 if (base_label == default_label)
1109 TREE_VEC_ELT (labels, i) = NULL_TREE;
1115 base_high = CASE_HIGH (base_case) ?
1116 CASE_HIGH (base_case) : CASE_LOW (base_case);
1118 /* Try to merge case labels. Break out when we reach the end
1119 of the label vector or when we cannot merge the next case
1120 label with the current one. */
1121 while (i < old_size - 1)
1123 tree merge_case = TREE_VEC_ELT (labels, i);
1124 tree merge_label = CASE_LABEL (merge_case);
1125 tree t = int_const_binop (PLUS_EXPR, base_high,
1126 integer_one_node, 1);
1128 /* Merge the cases if they jump to the same place,
1129 and their ranges are consecutive. */
1130 if (merge_label == base_label
1131 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1133 base_high = CASE_HIGH (merge_case) ?
1134 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1135 CASE_HIGH (base_case) = base_high;
1136 TREE_VEC_ELT (labels, i) = NULL_TREE;
1145 /* Compress the case labels in the label vector, and adjust the
1146 length of the vector. */
1147 for (i = 0, j = 0; i < new_size; i++)
1149 while (! TREE_VEC_ELT (labels, j))
1151 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1153 TREE_VEC_LENGTH (labels) = new_size;
1158 /* Checks whether we can merge block B into block A. */
1161 tree_can_merge_blocks_p (basic_block a, basic_block b)
1164 block_stmt_iterator bsi;
1167 if (!single_succ_p (a))
1170 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1173 if (single_succ (a) != b)
1176 if (!single_pred_p (b))
1179 if (b == EXIT_BLOCK_PTR)
1182 /* If A ends by a statement causing exceptions or something similar, we
1183 cannot merge the blocks. */
1184 stmt = last_stmt (a);
1185 if (stmt && stmt_ends_bb_p (stmt))
1188 /* Do not allow a block with only a non-local label to be merged. */
1189 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1190 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1193 /* It must be possible to eliminate all phi nodes in B. If ssa form
1194 is not up-to-date, we cannot eliminate any phis; however, if only
1195 some symbols as whole are marked for renaming, this is not a problem,
1196 as phi nodes for those symbols are irrelevant in updating anyway. */
1197 phi = phi_nodes (b);
1200 if (name_mappings_registered_p ())
1203 for (; phi; phi = PHI_CHAIN (phi))
1204 if (!is_gimple_reg (PHI_RESULT (phi))
1205 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1209 /* Do not remove user labels. */
1210 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1212 stmt = bsi_stmt (bsi);
1213 if (TREE_CODE (stmt) != LABEL_EXPR)
1215 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1219 /* Protect the loop latches. */
1221 && b->loop_father->latch == b)
1227 /* Replaces all uses of NAME by VAL. */
1230 replace_uses_by (tree name, tree val)
1232 imm_use_iterator imm_iter;
1237 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1239 if (TREE_CODE (stmt) != PHI_NODE)
1240 push_stmt_changes (&stmt);
1242 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1244 replace_exp (use, val);
1246 if (TREE_CODE (stmt) == PHI_NODE)
1248 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1249 if (e->flags & EDGE_ABNORMAL)
1251 /* This can only occur for virtual operands, since
1252 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1253 would prevent replacement. */
1254 gcc_assert (!is_gimple_reg (name));
1255 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1260 if (TREE_CODE (stmt) != PHI_NODE)
1264 fold_stmt_inplace (stmt);
1266 /* FIXME. This should go in pop_stmt_changes. */
1267 rhs = get_rhs (stmt);
1268 if (TREE_CODE (rhs) == ADDR_EXPR)
1269 recompute_tree_invariant_for_addr_expr (rhs);
1271 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1273 pop_stmt_changes (&stmt);
1277 gcc_assert (zero_imm_uses_p (name));
1279 /* Also update the trees stored in loop structures. */
1285 FOR_EACH_LOOP (li, loop, 0)
1287 substitute_in_loop_info (loop, name, val);
1292 /* Merge block B into block A. */
1295 tree_merge_blocks (basic_block a, basic_block b)
1297 block_stmt_iterator bsi;
1298 tree_stmt_iterator last;
1302 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1304 /* Remove all single-valued PHI nodes from block B of the form
1305 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1307 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1309 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1311 bool may_replace_uses = may_propagate_copy (def, use);
1313 /* In case we have loops to care about, do not propagate arguments of
1314 loop closed ssa phi nodes. */
1316 && is_gimple_reg (def)
1317 && TREE_CODE (use) == SSA_NAME
1318 && a->loop_father != b->loop_father)
1319 may_replace_uses = false;
1321 if (!may_replace_uses)
1323 gcc_assert (is_gimple_reg (def));
1325 /* Note that just emitting the copies is fine -- there is no problem
1326 with ordering of phi nodes. This is because A is the single
1327 predecessor of B, therefore results of the phi nodes cannot
1328 appear as arguments of the phi nodes. */
1329 copy = build2_gimple (GIMPLE_MODIFY_STMT, def, use);
1330 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1331 SSA_NAME_DEF_STMT (def) = copy;
1332 remove_phi_node (phi, NULL, false);
1336 replace_uses_by (def, use);
1337 remove_phi_node (phi, NULL, true);
1341 /* Ensure that B follows A. */
1342 move_block_after (b, a);
1344 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1345 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1347 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1348 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1350 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1352 tree label = bsi_stmt (bsi);
1354 bsi_remove (&bsi, false);
1355 /* Now that we can thread computed gotos, we might have
1356 a situation where we have a forced label in block B
1357 However, the label at the start of block B might still be
1358 used in other ways (think about the runtime checking for
1359 Fortran assigned gotos). So we can not just delete the
1360 label. Instead we move the label to the start of block A. */
1361 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1363 block_stmt_iterator dest_bsi = bsi_start (a);
1364 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1369 change_bb_for_stmt (bsi_stmt (bsi), a);
1374 /* Merge the chains. */
1375 last = tsi_last (a->stmt_list);
1376 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1377 b->stmt_list = NULL;
1381 /* Return the one of two successors of BB that is not reachable by a
1382 reached by a complex edge, if there is one. Else, return BB. We use
1383 this in optimizations that use post-dominators for their heuristics,
1384 to catch the cases in C++ where function calls are involved. */
1387 single_noncomplex_succ (basic_block bb)
1390 if (EDGE_COUNT (bb->succs) != 2)
1393 e0 = EDGE_SUCC (bb, 0);
1394 e1 = EDGE_SUCC (bb, 1);
1395 if (e0->flags & EDGE_COMPLEX)
1397 if (e1->flags & EDGE_COMPLEX)
1404 /* Walk the function tree removing unnecessary statements.
1406 * Empty statement nodes are removed
1408 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1410 * Unnecessary COND_EXPRs are removed
1412 * Some unnecessary BIND_EXPRs are removed
1414 Clearly more work could be done. The trick is doing the analysis
1415 and removal fast enough to be a net improvement in compile times.
1417 Note that when we remove a control structure such as a COND_EXPR
1418 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1419 to ensure we eliminate all the useless code. */
1430 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1433 remove_useless_stmts_warn_notreached (tree stmt)
1435 if (EXPR_HAS_LOCATION (stmt))
1437 location_t loc = EXPR_LOCATION (stmt);
1438 if (LOCATION_LINE (loc) > 0)
1440 warning (0, "%Hwill never be executed", &loc);
1445 switch (TREE_CODE (stmt))
1447 case STATEMENT_LIST:
1449 tree_stmt_iterator i;
1450 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1451 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1457 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1459 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1461 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1465 case TRY_FINALLY_EXPR:
1466 case TRY_CATCH_EXPR:
1467 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1469 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1474 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1475 case EH_FILTER_EXPR:
1476 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1478 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1481 /* Not a live container. */
1489 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1491 tree then_clause, else_clause, cond;
1492 bool save_has_label, then_has_label, else_has_label;
1494 save_has_label = data->has_label;
1495 data->has_label = false;
1496 data->last_goto = NULL;
1498 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1500 then_has_label = data->has_label;
1501 data->has_label = false;
1502 data->last_goto = NULL;
1504 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1506 else_has_label = data->has_label;
1507 data->has_label = save_has_label | then_has_label | else_has_label;
1509 then_clause = COND_EXPR_THEN (*stmt_p);
1510 else_clause = COND_EXPR_ELSE (*stmt_p);
1511 cond = fold (COND_EXPR_COND (*stmt_p));
1513 /* If neither arm does anything at all, we can remove the whole IF. */
1514 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1516 *stmt_p = build_empty_stmt ();
1517 data->repeat = true;
1520 /* If there are no reachable statements in an arm, then we can
1521 zap the entire conditional. */
1522 else if (integer_nonzerop (cond) && !else_has_label)
1524 if (warn_notreached)
1525 remove_useless_stmts_warn_notreached (else_clause);
1526 *stmt_p = then_clause;
1527 data->repeat = true;
1529 else if (integer_zerop (cond) && !then_has_label)
1531 if (warn_notreached)
1532 remove_useless_stmts_warn_notreached (then_clause);
1533 *stmt_p = else_clause;
1534 data->repeat = true;
1537 /* Check a couple of simple things on then/else with single stmts. */
1540 tree then_stmt = expr_only (then_clause);
1541 tree else_stmt = expr_only (else_clause);
1543 /* Notice branches to a common destination. */
1544 if (then_stmt && else_stmt
1545 && TREE_CODE (then_stmt) == GOTO_EXPR
1546 && TREE_CODE (else_stmt) == GOTO_EXPR
1547 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1549 *stmt_p = then_stmt;
1550 data->repeat = true;
1553 /* If the THEN/ELSE clause merely assigns a value to a variable or
1554 parameter which is already known to contain that value, then
1555 remove the useless THEN/ELSE clause. */
1556 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1559 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1560 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1561 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1562 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1564 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1565 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1566 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1567 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1569 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1570 ? then_stmt : else_stmt);
1571 tree *location = (TREE_CODE (cond) == EQ_EXPR
1572 ? &COND_EXPR_THEN (*stmt_p)
1573 : &COND_EXPR_ELSE (*stmt_p));
1576 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1577 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1578 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1579 *location = alloc_stmt_list ();
1583 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1584 would be re-introduced during lowering. */
1585 data->last_goto = NULL;
1590 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1592 bool save_may_branch, save_may_throw;
1593 bool this_may_branch, this_may_throw;
1595 /* Collect may_branch and may_throw information for the body only. */
1596 save_may_branch = data->may_branch;
1597 save_may_throw = data->may_throw;
1598 data->may_branch = false;
1599 data->may_throw = false;
1600 data->last_goto = NULL;
1602 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1604 this_may_branch = data->may_branch;
1605 this_may_throw = data->may_throw;
1606 data->may_branch |= save_may_branch;
1607 data->may_throw |= save_may_throw;
1608 data->last_goto = NULL;
1610 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1612 /* If the body is empty, then we can emit the FINALLY block without
1613 the enclosing TRY_FINALLY_EXPR. */
1614 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1616 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1617 data->repeat = true;
1620 /* If the handler is empty, then we can emit the TRY block without
1621 the enclosing TRY_FINALLY_EXPR. */
1622 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1624 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1625 data->repeat = true;
1628 /* If the body neither throws, nor branches, then we can safely
1629 string the TRY and FINALLY blocks together. */
1630 else if (!this_may_branch && !this_may_throw)
1632 tree stmt = *stmt_p;
1633 *stmt_p = TREE_OPERAND (stmt, 0);
1634 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1635 data->repeat = true;
1641 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1643 bool save_may_throw, this_may_throw;
1644 tree_stmt_iterator i;
1647 /* Collect may_throw information for the body only. */
1648 save_may_throw = data->may_throw;
1649 data->may_throw = false;
1650 data->last_goto = NULL;
1652 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1654 this_may_throw = data->may_throw;
1655 data->may_throw = save_may_throw;
1657 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1658 if (!this_may_throw)
1660 if (warn_notreached)
1661 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1662 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1663 data->repeat = true;
1667 /* Process the catch clause specially. We may be able to tell that
1668 no exceptions propagate past this point. */
1670 this_may_throw = true;
1671 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1672 stmt = tsi_stmt (i);
1673 data->last_goto = NULL;
1675 switch (TREE_CODE (stmt))
1678 for (; !tsi_end_p (i); tsi_next (&i))
1680 stmt = tsi_stmt (i);
1681 /* If we catch all exceptions, then the body does not
1682 propagate exceptions past this point. */
1683 if (CATCH_TYPES (stmt) == NULL)
1684 this_may_throw = false;
1685 data->last_goto = NULL;
1686 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1690 case EH_FILTER_EXPR:
1691 if (EH_FILTER_MUST_NOT_THROW (stmt))
1692 this_may_throw = false;
1693 else if (EH_FILTER_TYPES (stmt) == NULL)
1694 this_may_throw = false;
1695 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1699 /* Otherwise this is a cleanup. */
1700 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1702 /* If the cleanup is empty, then we can emit the TRY block without
1703 the enclosing TRY_CATCH_EXPR. */
1704 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1706 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1707 data->repeat = true;
1711 data->may_throw |= this_may_throw;
1716 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1720 /* First remove anything underneath the BIND_EXPR. */
1721 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1723 /* If the BIND_EXPR has no variables, then we can pull everything
1724 up one level and remove the BIND_EXPR, unless this is the toplevel
1725 BIND_EXPR for the current function or an inlined function.
1727 When this situation occurs we will want to apply this
1728 optimization again. */
1729 block = BIND_EXPR_BLOCK (*stmt_p);
1730 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1731 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1733 || ! BLOCK_ABSTRACT_ORIGIN (block)
1734 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1737 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1738 data->repeat = true;
1744 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1746 tree dest = GOTO_DESTINATION (*stmt_p);
1748 data->may_branch = true;
1749 data->last_goto = NULL;
1751 /* Record the last goto expr, so that we can delete it if unnecessary. */
1752 if (TREE_CODE (dest) == LABEL_DECL)
1753 data->last_goto = stmt_p;
1758 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1760 tree label = LABEL_EXPR_LABEL (*stmt_p);
1762 data->has_label = true;
1764 /* We do want to jump across non-local label receiver code. */
1765 if (DECL_NONLOCAL (label))
1766 data->last_goto = NULL;
1768 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1770 *data->last_goto = build_empty_stmt ();
1771 data->repeat = true;
1774 /* ??? Add something here to delete unused labels. */
1778 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1779 decl. This allows us to eliminate redundant or useless
1780 calls to "const" functions.
1782 Gimplifier already does the same operation, but we may notice functions
1783 being const and pure once their calls has been gimplified, so we need
1784 to update the flag. */
1787 update_call_expr_flags (tree call)
1789 tree decl = get_callee_fndecl (call);
1792 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1793 TREE_SIDE_EFFECTS (call) = 0;
1794 if (TREE_NOTHROW (decl))
1795 TREE_NOTHROW (call) = 1;
1799 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1802 notice_special_calls (tree t)
1804 int flags = call_expr_flags (t);
1806 if (flags & ECF_MAY_BE_ALLOCA)
1807 current_function_calls_alloca = true;
1808 if (flags & ECF_RETURNS_TWICE)
1809 current_function_calls_setjmp = true;
1813 /* Clear flags set by notice_special_calls. Used by dead code removal
1814 to update the flags. */
1817 clear_special_calls (void)
1819 current_function_calls_alloca = false;
1820 current_function_calls_setjmp = false;
1825 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1829 switch (TREE_CODE (t))
1832 remove_useless_stmts_cond (tp, data);
1835 case TRY_FINALLY_EXPR:
1836 remove_useless_stmts_tf (tp, data);
1839 case TRY_CATCH_EXPR:
1840 remove_useless_stmts_tc (tp, data);
1844 remove_useless_stmts_bind (tp, data);
1848 remove_useless_stmts_goto (tp, data);
1852 remove_useless_stmts_label (tp, data);
1857 data->last_goto = NULL;
1858 data->may_branch = true;
1863 data->last_goto = NULL;
1864 notice_special_calls (t);
1865 update_call_expr_flags (t);
1866 if (tree_could_throw_p (t))
1867 data->may_throw = true;
1873 case GIMPLE_MODIFY_STMT:
1874 data->last_goto = NULL;
1876 op = get_call_expr_in (t);
1879 update_call_expr_flags (op);
1880 notice_special_calls (op);
1882 if (tree_could_throw_p (t))
1883 data->may_throw = true;
1886 case STATEMENT_LIST:
1888 tree_stmt_iterator i = tsi_start (t);
1889 while (!tsi_end_p (i))
1892 if (IS_EMPTY_STMT (t))
1898 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1901 if (TREE_CODE (t) == STATEMENT_LIST)
1903 tsi_link_before (&i, t, TSI_SAME_STMT);
1913 data->last_goto = NULL;
1917 data->last_goto = NULL;
1923 remove_useless_stmts (void)
1925 struct rus_data data;
1927 clear_special_calls ();
1931 memset (&data, 0, sizeof (data));
1932 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1934 while (data.repeat);
1939 struct tree_opt_pass pass_remove_useless_stmts =
1941 "useless", /* name */
1943 remove_useless_stmts, /* execute */
1946 0, /* static_pass_number */
1948 PROP_gimple_any, /* properties_required */
1949 0, /* properties_provided */
1950 0, /* properties_destroyed */
1951 0, /* todo_flags_start */
1952 TODO_dump_func, /* todo_flags_finish */
1956 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1959 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1963 /* Since this block is no longer reachable, we can just delete all
1964 of its PHI nodes. */
1965 phi = phi_nodes (bb);
1968 tree next = PHI_CHAIN (phi);
1969 remove_phi_node (phi, NULL_TREE, true);
1973 /* Remove edges to BB's successors. */
1974 while (EDGE_COUNT (bb->succs) > 0)
1975 remove_edge (EDGE_SUCC (bb, 0));
1979 /* Remove statements of basic block BB. */
1982 remove_bb (basic_block bb)
1984 block_stmt_iterator i;
1985 #ifdef USE_MAPPED_LOCATION
1986 source_location loc = UNKNOWN_LOCATION;
1988 source_locus loc = 0;
1993 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1994 if (dump_flags & TDF_DETAILS)
1996 dump_bb (bb, dump_file, 0);
1997 fprintf (dump_file, "\n");
2003 struct loop *loop = bb->loop_father;
2005 /* If a loop gets removed, clean up the information associated
2007 if (loop->latch == bb
2008 || loop->header == bb)
2009 free_numbers_of_iterations_estimates_loop (loop);
2012 /* Remove all the instructions in the block. */
2013 for (i = bsi_start (bb); !bsi_end_p (i);)
2015 tree stmt = bsi_stmt (i);
2016 if (TREE_CODE (stmt) == LABEL_EXPR
2017 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2018 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2021 block_stmt_iterator new_bsi;
2023 /* A non-reachable non-local label may still be referenced.
2024 But it no longer needs to carry the extra semantics of
2026 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2028 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2029 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2032 new_bb = bb->prev_bb;
2033 new_bsi = bsi_start (new_bb);
2034 bsi_remove (&i, false);
2035 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2039 /* Release SSA definitions if we are in SSA. Note that we
2040 may be called when not in SSA. For example,
2041 final_cleanup calls this function via
2042 cleanup_tree_cfg. */
2043 if (gimple_in_ssa_p (cfun))
2044 release_defs (stmt);
2046 bsi_remove (&i, true);
2049 /* Don't warn for removed gotos. Gotos are often removed due to
2050 jump threading, thus resulting in bogus warnings. Not great,
2051 since this way we lose warnings for gotos in the original
2052 program that are indeed unreachable. */
2053 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2055 #ifdef USE_MAPPED_LOCATION
2056 if (EXPR_HAS_LOCATION (stmt))
2057 loc = EXPR_LOCATION (stmt);
2060 t = EXPR_LOCUS (stmt);
2061 if (t && LOCATION_LINE (*t) > 0)
2067 /* If requested, give a warning that the first statement in the
2068 block is unreachable. We walk statements backwards in the
2069 loop above, so the last statement we process is the first statement
2071 #ifdef USE_MAPPED_LOCATION
2072 if (loc > BUILTINS_LOCATION)
2073 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2076 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2079 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2083 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2084 predicate VAL, return the edge that will be taken out of the block.
2085 If VAL does not match a unique edge, NULL is returned. */
2088 find_taken_edge (basic_block bb, tree val)
2092 stmt = last_stmt (bb);
2095 gcc_assert (is_ctrl_stmt (stmt));
2098 if (! is_gimple_min_invariant (val))
2101 if (TREE_CODE (stmt) == COND_EXPR)
2102 return find_taken_edge_cond_expr (bb, val);
2104 if (TREE_CODE (stmt) == SWITCH_EXPR)
2105 return find_taken_edge_switch_expr (bb, val);
2107 if (computed_goto_p (stmt))
2108 return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
2113 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2114 statement, determine which of the outgoing edges will be taken out of the
2115 block. Return NULL if either edge may be taken. */
2118 find_taken_edge_computed_goto (basic_block bb, tree val)
2123 dest = label_to_block (val);
2126 e = find_edge (bb, dest);
2127 gcc_assert (e != NULL);
2133 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2134 statement, determine which of the two edges will be taken out of the
2135 block. Return NULL if either edge may be taken. */
2138 find_taken_edge_cond_expr (basic_block bb, tree val)
2140 edge true_edge, false_edge;
2142 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2144 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2145 return (integer_zerop (val) ? false_edge : true_edge);
2148 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2149 statement, determine which edge will be taken out of the block. Return
2150 NULL if any edge may be taken. */
2153 find_taken_edge_switch_expr (basic_block bb, tree val)
2155 tree switch_expr, taken_case;
2156 basic_block dest_bb;
2159 switch_expr = last_stmt (bb);
2160 taken_case = find_case_label_for_value (switch_expr, val);
2161 dest_bb = label_to_block (CASE_LABEL (taken_case));
2163 e = find_edge (bb, dest_bb);
2169 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2170 We can make optimal use here of the fact that the case labels are
2171 sorted: We can do a binary search for a case matching VAL. */
2174 find_case_label_for_value (tree switch_expr, tree val)
2176 tree vec = SWITCH_LABELS (switch_expr);
2177 size_t low, high, n = TREE_VEC_LENGTH (vec);
2178 tree default_case = TREE_VEC_ELT (vec, n - 1);
2180 for (low = -1, high = n - 1; high - low > 1; )
2182 size_t i = (high + low) / 2;
2183 tree t = TREE_VEC_ELT (vec, i);
2186 /* Cache the result of comparing CASE_LOW and val. */
2187 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2194 if (CASE_HIGH (t) == NULL)
2196 /* A singe-valued case label. */
2202 /* A case range. We can only handle integer ranges. */
2203 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2208 return default_case;
2214 /*---------------------------------------------------------------------------
2216 ---------------------------------------------------------------------------*/
2218 /* Dump tree-specific information of block BB to file OUTF. */
2221 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2223 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2227 /* Dump a basic block on stderr. */
2230 debug_tree_bb (basic_block bb)
2232 dump_bb (bb, stderr, 0);
2236 /* Dump basic block with index N on stderr. */
2239 debug_tree_bb_n (int n)
2241 debug_tree_bb (BASIC_BLOCK (n));
2242 return BASIC_BLOCK (n);
2246 /* Dump the CFG on stderr.
2248 FLAGS are the same used by the tree dumping functions
2249 (see TDF_* in tree-pass.h). */
2252 debug_tree_cfg (int flags)
2254 dump_tree_cfg (stderr, flags);
2258 /* Dump the program showing basic block boundaries on the given FILE.
2260 FLAGS are the same used by the tree dumping functions (see TDF_* in
2264 dump_tree_cfg (FILE *file, int flags)
2266 if (flags & TDF_DETAILS)
2268 const char *funcname
2269 = lang_hooks.decl_printable_name (current_function_decl, 2);
2272 fprintf (file, ";; Function %s\n\n", funcname);
2273 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2274 n_basic_blocks, n_edges, last_basic_block);
2276 brief_dump_cfg (file);
2277 fprintf (file, "\n");
2280 if (flags & TDF_STATS)
2281 dump_cfg_stats (file);
2283 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2287 /* Dump CFG statistics on FILE. */
2290 dump_cfg_stats (FILE *file)
2292 static long max_num_merged_labels = 0;
2293 unsigned long size, total = 0;
2296 const char * const fmt_str = "%-30s%-13s%12s\n";
2297 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2298 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2299 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2300 const char *funcname
2301 = lang_hooks.decl_printable_name (current_function_decl, 2);
2304 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2306 fprintf (file, "---------------------------------------------------------\n");
2307 fprintf (file, fmt_str, "", " Number of ", "Memory");
2308 fprintf (file, fmt_str, "", " instances ", "used ");
2309 fprintf (file, "---------------------------------------------------------\n");
2311 size = n_basic_blocks * sizeof (struct basic_block_def);
2313 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2314 SCALE (size), LABEL (size));
2318 num_edges += EDGE_COUNT (bb->succs);
2319 size = num_edges * sizeof (struct edge_def);
2321 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2323 fprintf (file, "---------------------------------------------------------\n");
2324 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2326 fprintf (file, "---------------------------------------------------------\n");
2327 fprintf (file, "\n");
2329 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2330 max_num_merged_labels = cfg_stats.num_merged_labels;
2332 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2333 cfg_stats.num_merged_labels, max_num_merged_labels);
2335 fprintf (file, "\n");
2339 /* Dump CFG statistics on stderr. Keep extern so that it's always
2340 linked in the final executable. */
2343 debug_cfg_stats (void)
2345 dump_cfg_stats (stderr);
2349 /* Dump the flowgraph to a .vcg FILE. */
2352 tree_cfg2vcg (FILE *file)
2357 const char *funcname
2358 = lang_hooks.decl_printable_name (current_function_decl, 2);
2360 /* Write the file header. */
2361 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2362 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2363 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2365 /* Write blocks and edges. */
2366 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2368 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2371 if (e->flags & EDGE_FAKE)
2372 fprintf (file, " linestyle: dotted priority: 10");
2374 fprintf (file, " linestyle: solid priority: 100");
2376 fprintf (file, " }\n");
2382 enum tree_code head_code, end_code;
2383 const char *head_name, *end_name;
2386 tree first = first_stmt (bb);
2387 tree last = last_stmt (bb);
2391 head_code = TREE_CODE (first);
2392 head_name = tree_code_name[head_code];
2393 head_line = get_lineno (first);
2396 head_name = "no-statement";
2400 end_code = TREE_CODE (last);
2401 end_name = tree_code_name[end_code];
2402 end_line = get_lineno (last);
2405 end_name = "no-statement";
2407 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2408 bb->index, bb->index, head_name, head_line, end_name,
2411 FOR_EACH_EDGE (e, ei, bb->succs)
2413 if (e->dest == EXIT_BLOCK_PTR)
2414 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2416 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2418 if (e->flags & EDGE_FAKE)
2419 fprintf (file, " priority: 10 linestyle: dotted");
2421 fprintf (file, " priority: 100 linestyle: solid");
2423 fprintf (file, " }\n");
2426 if (bb->next_bb != EXIT_BLOCK_PTR)
2430 fputs ("}\n\n", file);
2435 /*---------------------------------------------------------------------------
2436 Miscellaneous helpers
2437 ---------------------------------------------------------------------------*/
2439 /* Return true if T represents a stmt that always transfers control. */
2442 is_ctrl_stmt (tree t)
2444 return (TREE_CODE (t) == COND_EXPR
2445 || TREE_CODE (t) == SWITCH_EXPR
2446 || TREE_CODE (t) == GOTO_EXPR
2447 || TREE_CODE (t) == RETURN_EXPR
2448 || TREE_CODE (t) == RESX_EXPR);
2452 /* Return true if T is a statement that may alter the flow of control
2453 (e.g., a call to a non-returning function). */
2456 is_ctrl_altering_stmt (tree t)
2461 call = get_call_expr_in (t);
2464 /* A non-pure/const CALL_EXPR alters flow control if the current
2465 function has nonlocal labels. */
2466 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2469 /* A CALL_EXPR also alters control flow if it does not return. */
2470 if (call_expr_flags (call) & ECF_NORETURN)
2474 /* OpenMP directives alter control flow. */
2475 if (OMP_DIRECTIVE_P (t))
2478 /* If a statement can throw, it alters control flow. */
2479 return tree_can_throw_internal (t);
2483 /* Return true if T is a computed goto. */
2486 computed_goto_p (tree t)
2488 return (TREE_CODE (t) == GOTO_EXPR
2489 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2493 /* Return true if T is a simple local goto. */
2496 simple_goto_p (tree t)
2498 return (TREE_CODE (t) == GOTO_EXPR
2499 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2503 /* Return true if T can make an abnormal transfer of control flow.
2504 Transfers of control flow associated with EH are excluded. */
2507 tree_can_make_abnormal_goto (tree t)
2509 if (computed_goto_p (t))
2511 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2512 t = GIMPLE_STMT_OPERAND (t, 1);
2513 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2514 t = TREE_OPERAND (t, 0);
2515 if (TREE_CODE (t) == CALL_EXPR)
2516 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2521 /* Return true if T should start a new basic block. PREV_T is the
2522 statement preceding T. It is used when T is a label or a case label.
2523 Labels should only start a new basic block if their previous statement
2524 wasn't a label. Otherwise, sequence of labels would generate
2525 unnecessary basic blocks that only contain a single label. */
2528 stmt_starts_bb_p (tree t, tree prev_t)
2533 /* LABEL_EXPRs start a new basic block only if the preceding
2534 statement wasn't a label of the same type. This prevents the
2535 creation of consecutive blocks that have nothing but a single
2537 if (TREE_CODE (t) == LABEL_EXPR)
2539 /* Nonlocal and computed GOTO targets always start a new block. */
2540 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2541 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2544 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2546 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2549 cfg_stats.num_merged_labels++;
2560 /* Return true if T should end a basic block. */
2563 stmt_ends_bb_p (tree t)
2565 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2569 /* Add gotos that used to be represented implicitly in the CFG. */
2572 disband_implicit_edges (void)
2575 block_stmt_iterator last;
2582 last = bsi_last (bb);
2583 stmt = last_stmt (bb);
2585 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2587 /* Remove superfluous gotos from COND_EXPR branches. Moved
2588 from cfg_remove_useless_stmts here since it violates the
2589 invariants for tree--cfg correspondence and thus fits better
2590 here where we do it anyway. */
2591 e = find_edge (bb, bb->next_bb);
2594 if (e->flags & EDGE_TRUE_VALUE)
2595 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2596 else if (e->flags & EDGE_FALSE_VALUE)
2597 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2600 e->flags |= EDGE_FALLTHRU;
2606 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2608 /* Remove the RETURN_EXPR if we may fall though to the exit
2610 gcc_assert (single_succ_p (bb));
2611 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2613 if (bb->next_bb == EXIT_BLOCK_PTR
2614 && !TREE_OPERAND (stmt, 0))
2616 bsi_remove (&last, true);
2617 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2622 /* There can be no fallthru edge if the last statement is a control
2624 if (stmt && is_ctrl_stmt (stmt))
2627 /* Find a fallthru edge and emit the goto if necessary. */
2628 FOR_EACH_EDGE (e, ei, bb->succs)
2629 if (e->flags & EDGE_FALLTHRU)
2632 if (!e || e->dest == bb->next_bb)
2635 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2636 label = tree_block_label (e->dest);
2638 stmt = build1 (GOTO_EXPR, void_type_node, label);
2639 #ifdef USE_MAPPED_LOCATION
2640 SET_EXPR_LOCATION (stmt, e->goto_locus);
2642 SET_EXPR_LOCUS (stmt, e->goto_locus);
2644 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2645 e->flags &= ~EDGE_FALLTHRU;
2649 /* Remove block annotations and other datastructures. */
2652 delete_tree_cfg_annotations (void)
2655 block_stmt_iterator bsi;
2657 /* Remove annotations from every tree in the function. */
2659 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2661 tree stmt = bsi_stmt (bsi);
2662 ggc_free (stmt->base.ann);
2663 stmt->base.ann = NULL;
2665 label_to_block_map = NULL;
2669 /* Return the first statement in basic block BB. */
2672 first_stmt (basic_block bb)
2674 block_stmt_iterator i = bsi_start (bb);
2675 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2679 /* Return the last statement in basic block BB. */
2682 last_stmt (basic_block bb)
2684 block_stmt_iterator b = bsi_last (bb);
2685 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2689 /* Return the last statement of an otherwise empty block. Return NULL
2690 if the block is totally empty, or if it contains more than one
2694 last_and_only_stmt (basic_block bb)
2696 block_stmt_iterator i = bsi_last (bb);
2702 last = bsi_stmt (i);
2707 /* Empty statements should no longer appear in the instruction stream.
2708 Everything that might have appeared before should be deleted by
2709 remove_useless_stmts, and the optimizers should just bsi_remove
2710 instead of smashing with build_empty_stmt.
2712 Thus the only thing that should appear here in a block containing
2713 one executable statement is a label. */
2714 prev = bsi_stmt (i);
2715 if (TREE_CODE (prev) == LABEL_EXPR)
2722 /* Mark BB as the basic block holding statement T. */
2725 set_bb_for_stmt (tree t, basic_block bb)
2727 if (TREE_CODE (t) == PHI_NODE)
2729 else if (TREE_CODE (t) == STATEMENT_LIST)
2731 tree_stmt_iterator i;
2732 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2733 set_bb_for_stmt (tsi_stmt (i), bb);
2737 stmt_ann_t ann = get_stmt_ann (t);
2740 /* If the statement is a label, add the label to block-to-labels map
2741 so that we can speed up edge creation for GOTO_EXPRs. */
2742 if (TREE_CODE (t) == LABEL_EXPR)
2746 t = LABEL_EXPR_LABEL (t);
2747 uid = LABEL_DECL_UID (t);
2750 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2751 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2752 if (old_len <= (unsigned) uid)
2754 unsigned new_len = 3 * uid / 2;
2756 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2761 /* We're moving an existing label. Make sure that we've
2762 removed it from the old block. */
2764 || !VEC_index (basic_block, label_to_block_map, uid));
2765 VEC_replace (basic_block, label_to_block_map, uid, bb);
2770 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2771 from one basic block to another.
2772 For BB splitting we can run into quadratic case, so performance is quite
2773 important and knowing that the tables are big enough, change_bb_for_stmt
2774 can inline as leaf function. */
2776 change_bb_for_stmt (tree t, basic_block bb)
2778 get_stmt_ann (t)->bb = bb;
2779 if (TREE_CODE (t) == LABEL_EXPR)
2780 VEC_replace (basic_block, label_to_block_map,
2781 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2784 /* Finds iterator for STMT. */
2786 extern block_stmt_iterator
2787 bsi_for_stmt (tree stmt)
2789 block_stmt_iterator bsi;
2791 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2792 if (bsi_stmt (bsi) == stmt)
2798 /* Mark statement T as modified, and update it. */
2800 update_modified_stmts (tree t)
2802 if (!ssa_operands_active ())
2804 if (TREE_CODE (t) == STATEMENT_LIST)
2806 tree_stmt_iterator i;
2808 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2810 stmt = tsi_stmt (i);
2811 update_stmt_if_modified (stmt);
2815 update_stmt_if_modified (t);
2818 /* Insert statement (or statement list) T before the statement
2819 pointed-to by iterator I. M specifies how to update iterator I
2820 after insertion (see enum bsi_iterator_update). */
2823 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2825 set_bb_for_stmt (t, i->bb);
2826 update_modified_stmts (t);
2827 tsi_link_before (&i->tsi, t, m);
2831 /* Insert statement (or statement list) T after the statement
2832 pointed-to by iterator I. M specifies how to update iterator I
2833 after insertion (see enum bsi_iterator_update). */
2836 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2838 set_bb_for_stmt (t, i->bb);
2839 update_modified_stmts (t);
2840 tsi_link_after (&i->tsi, t, m);
2844 /* Remove the statement pointed to by iterator I. The iterator is updated
2845 to the next statement.
2847 When REMOVE_EH_INFO is true we remove the statement pointed to by
2848 iterator I from the EH tables. Otherwise we do not modify the EH
2851 Generally, REMOVE_EH_INFO should be true when the statement is going to
2852 be removed from the IL and not reinserted elsewhere. */
2855 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2857 tree t = bsi_stmt (*i);
2858 set_bb_for_stmt (t, NULL);
2859 delink_stmt_imm_use (t);
2860 tsi_delink (&i->tsi);
2861 mark_stmt_modified (t);
2864 remove_stmt_from_eh_region (t);
2865 gimple_remove_stmt_histograms (cfun, t);
2870 /* Move the statement at FROM so it comes right after the statement at TO. */
2873 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2875 tree stmt = bsi_stmt (*from);
2876 bsi_remove (from, false);
2877 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2881 /* Move the statement at FROM so it comes right before the statement at TO. */
2884 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2886 tree stmt = bsi_stmt (*from);
2887 bsi_remove (from, false);
2888 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2892 /* Move the statement at FROM to the end of basic block BB. */
2895 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2897 block_stmt_iterator last = bsi_last (bb);
2899 /* Have to check bsi_end_p because it could be an empty block. */
2900 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2901 bsi_move_before (from, &last);
2903 bsi_move_after (from, &last);
2907 /* Replace the contents of the statement pointed to by iterator BSI
2908 with STMT. If UPDATE_EH_INFO is true, the exception handling
2909 information of the original statement is moved to the new statement. */
2912 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2915 tree orig_stmt = bsi_stmt (*bsi);
2917 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2918 set_bb_for_stmt (stmt, bsi->bb);
2920 /* Preserve EH region information from the original statement, if
2921 requested by the caller. */
2924 eh_region = lookup_stmt_eh_region (orig_stmt);
2927 remove_stmt_from_eh_region (orig_stmt);
2928 add_stmt_to_eh_region (stmt, eh_region);
2929 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2930 gimple_remove_stmt_histograms (cfun, orig_stmt);
2934 delink_stmt_imm_use (orig_stmt);
2935 *bsi_stmt_ptr (*bsi) = stmt;
2936 mark_stmt_modified (stmt);
2937 update_modified_stmts (stmt);
2941 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2942 is made to place the statement in an existing basic block, but
2943 sometimes that isn't possible. When it isn't possible, the edge is
2944 split and the statement is added to the new block.
2946 In all cases, the returned *BSI points to the correct location. The
2947 return value is true if insertion should be done after the location,
2948 or false if it should be done before the location. If new basic block
2949 has to be created, it is stored in *NEW_BB. */
2952 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2953 basic_block *new_bb)
2955 basic_block dest, src;
2961 /* If the destination has one predecessor which has no PHI nodes,
2962 insert there. Except for the exit block.
2964 The requirement for no PHI nodes could be relaxed. Basically we
2965 would have to examine the PHIs to prove that none of them used
2966 the value set by the statement we want to insert on E. That
2967 hardly seems worth the effort. */
2968 if (single_pred_p (dest)
2969 && ! phi_nodes (dest)
2970 && dest != EXIT_BLOCK_PTR)
2972 *bsi = bsi_start (dest);
2973 if (bsi_end_p (*bsi))
2976 /* Make sure we insert after any leading labels. */
2977 tmp = bsi_stmt (*bsi);
2978 while (TREE_CODE (tmp) == LABEL_EXPR)
2981 if (bsi_end_p (*bsi))
2983 tmp = bsi_stmt (*bsi);
2986 if (bsi_end_p (*bsi))
2988 *bsi = bsi_last (dest);
2995 /* If the source has one successor, the edge is not abnormal and
2996 the last statement does not end a basic block, insert there.
2997 Except for the entry block. */
2999 if ((e->flags & EDGE_ABNORMAL) == 0
3000 && single_succ_p (src)
3001 && src != ENTRY_BLOCK_PTR)
3003 *bsi = bsi_last (src);
3004 if (bsi_end_p (*bsi))
3007 tmp = bsi_stmt (*bsi);
3008 if (!stmt_ends_bb_p (tmp))
3011 /* Insert code just before returning the value. We may need to decompose
3012 the return in the case it contains non-trivial operand. */
3013 if (TREE_CODE (tmp) == RETURN_EXPR)
3015 tree op = TREE_OPERAND (tmp, 0);
3016 if (op && !is_gimple_val (op))
3018 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
3019 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3020 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
3027 /* Otherwise, create a new basic block, and split this edge. */
3028 dest = split_edge (e);
3031 e = single_pred_edge (dest);
3036 /* This routine will commit all pending edge insertions, creating any new
3037 basic blocks which are necessary. */
3040 bsi_commit_edge_inserts (void)
3046 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3049 FOR_EACH_EDGE (e, ei, bb->succs)
3050 bsi_commit_one_edge_insert (e, NULL);
3054 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3055 to this block, otherwise set it to NULL. */
3058 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3062 if (PENDING_STMT (e))
3064 block_stmt_iterator bsi;
3065 tree stmt = PENDING_STMT (e);
3067 PENDING_STMT (e) = NULL_TREE;
3069 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3070 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3072 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3077 /* Add STMT to the pending list of edge E. No actual insertion is
3078 made until a call to bsi_commit_edge_inserts () is made. */
3081 bsi_insert_on_edge (edge e, tree stmt)
3083 append_to_statement_list (stmt, &PENDING_STMT (e));
3086 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3087 block has to be created, it is returned. */
3090 bsi_insert_on_edge_immediate (edge e, tree stmt)
3092 block_stmt_iterator bsi;
3093 basic_block new_bb = NULL;
3095 gcc_assert (!PENDING_STMT (e));
3097 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3098 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3100 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3105 /*---------------------------------------------------------------------------
3106 Tree specific functions for CFG manipulation
3107 ---------------------------------------------------------------------------*/
3109 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3112 reinstall_phi_args (edge new_edge, edge old_edge)
3116 if (!PENDING_STMT (old_edge))
3119 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3121 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3123 tree result = TREE_PURPOSE (var);
3124 tree arg = TREE_VALUE (var);
3126 gcc_assert (result == PHI_RESULT (phi));
3128 add_phi_arg (phi, arg, new_edge);
3131 PENDING_STMT (old_edge) = NULL;
3134 /* Returns the basic block after which the new basic block created
3135 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3136 near its "logical" location. This is of most help to humans looking
3137 at debugging dumps. */
3140 split_edge_bb_loc (edge edge_in)
3142 basic_block dest = edge_in->dest;
3144 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3145 return edge_in->src;
3147 return dest->prev_bb;
3150 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3151 Abort on abnormal edges. */
3154 tree_split_edge (edge edge_in)
3156 basic_block new_bb, after_bb, dest;
3159 /* Abnormal edges cannot be split. */
3160 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3162 dest = edge_in->dest;
3164 after_bb = split_edge_bb_loc (edge_in);
3166 new_bb = create_empty_bb (after_bb);
3167 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3168 new_bb->count = edge_in->count;
3169 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3170 new_edge->probability = REG_BR_PROB_BASE;
3171 new_edge->count = edge_in->count;
3173 e = redirect_edge_and_branch (edge_in, new_bb);
3175 reinstall_phi_args (new_edge, e);
3181 /* Return true when BB has label LABEL in it. */
3184 has_label_p (basic_block bb, tree label)
3186 block_stmt_iterator bsi;
3188 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3190 tree stmt = bsi_stmt (bsi);
3192 if (TREE_CODE (stmt) != LABEL_EXPR)
3194 if (LABEL_EXPR_LABEL (stmt) == label)
3201 /* Callback for walk_tree, check that all elements with address taken are
3202 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3203 inside a PHI node. */
3206 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3209 bool in_phi = (data != NULL);
3214 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3215 #define CHECK_OP(N, MSG) \
3216 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3217 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3219 switch (TREE_CODE (t))
3222 if (SSA_NAME_IN_FREE_LIST (t))
3224 error ("SSA name in freelist but still referenced");
3230 x = fold (ASSERT_EXPR_COND (t));
3231 if (x == boolean_false_node)
3233 error ("ASSERT_EXPR with an always-false condition");
3241 case GIMPLE_MODIFY_STMT:
3242 x = GIMPLE_STMT_OPERAND (t, 0);
3243 if (TREE_CODE (x) == BIT_FIELD_REF
3244 && is_gimple_reg (TREE_OPERAND (x, 0)))
3246 error ("GIMPLE register modified with BIT_FIELD_REF");
3255 bool old_side_effects;
3258 bool new_side_effects;
3260 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3261 dead PHIs that take the address of something. But if the PHI
3262 result is dead, the fact that it takes the address of anything
3263 is irrelevant. Because we can not tell from here if a PHI result
3264 is dead, we just skip this check for PHIs altogether. This means
3265 we may be missing "valid" checks, but what can you do?
3266 This was PR19217. */
3270 old_invariant = TREE_INVARIANT (t);
3271 old_constant = TREE_CONSTANT (t);
3272 old_side_effects = TREE_SIDE_EFFECTS (t);
3274 recompute_tree_invariant_for_addr_expr (t);
3275 new_invariant = TREE_INVARIANT (t);
3276 new_side_effects = TREE_SIDE_EFFECTS (t);
3277 new_constant = TREE_CONSTANT (t);
3279 if (old_invariant != new_invariant)
3281 error ("invariant not recomputed when ADDR_EXPR changed");
3285 if (old_constant != new_constant)
3287 error ("constant not recomputed when ADDR_EXPR changed");
3290 if (old_side_effects != new_side_effects)
3292 error ("side effects not recomputed when ADDR_EXPR changed");
3296 /* Skip any references (they will be checked when we recurse down the
3297 tree) and ensure that any variable used as a prefix is marked
3299 for (x = TREE_OPERAND (t, 0);
3300 handled_component_p (x);
3301 x = TREE_OPERAND (x, 0))
3304 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3306 if (!TREE_ADDRESSABLE (x))
3308 error ("address taken, but ADDRESSABLE bit not set");
3315 x = COND_EXPR_COND (t);
3316 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3318 error ("non-boolean used in condition");
3321 if (!is_gimple_condexpr (x))
3323 error ("invalid conditional operand");
3330 case FIX_TRUNC_EXPR:
3335 case NON_LVALUE_EXPR:
3336 case TRUTH_NOT_EXPR:
3337 CHECK_OP (0, "invalid operand to unary operator");
3344 case ARRAY_RANGE_REF:
3346 case VIEW_CONVERT_EXPR:
3347 /* We have a nest of references. Verify that each of the operands
3348 that determine where to reference is either a constant or a variable,
3349 verify that the base is valid, and then show we've already checked
3351 while (handled_component_p (t))
3353 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3354 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3355 else if (TREE_CODE (t) == ARRAY_REF
3356 || TREE_CODE (t) == ARRAY_RANGE_REF)
3358 CHECK_OP (1, "invalid array index");
3359 if (TREE_OPERAND (t, 2))
3360 CHECK_OP (2, "invalid array lower bound");
3361 if (TREE_OPERAND (t, 3))
3362 CHECK_OP (3, "invalid array stride");
3364 else if (TREE_CODE (t) == BIT_FIELD_REF)
3366 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3367 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3370 t = TREE_OPERAND (t, 0);
3373 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3375 error ("invalid reference prefix");
3387 case UNORDERED_EXPR:
3398 case TRUNC_DIV_EXPR:
3400 case FLOOR_DIV_EXPR:
3401 case ROUND_DIV_EXPR:
3402 case TRUNC_MOD_EXPR:
3404 case FLOOR_MOD_EXPR:
3405 case ROUND_MOD_EXPR:
3407 case EXACT_DIV_EXPR:
3417 CHECK_OP (0, "invalid operand to binary operator");
3418 CHECK_OP (1, "invalid operand to binary operator");
3422 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3435 /* Verify STMT, return true if STMT is not in GIMPLE form.
3436 TODO: Implement type checking. */
3439 verify_stmt (tree stmt, bool last_in_block)
3443 if (OMP_DIRECTIVE_P (stmt))
3445 /* OpenMP directives are validated by the FE and never operated
3446 on by the optimizers. Furthermore, OMP_FOR may contain
3447 non-gimple expressions when the main index variable has had
3448 its address taken. This does not affect the loop itself
3449 because the header of an OMP_FOR is merely used to determine
3450 how to setup the parallel iteration. */
3454 if (!is_gimple_stmt (stmt))
3456 error ("is not a valid GIMPLE statement");
3460 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3463 debug_generic_stmt (addr);
3467 /* If the statement is marked as part of an EH region, then it is
3468 expected that the statement could throw. Verify that when we
3469 have optimizations that simplify statements such that we prove
3470 that they cannot throw, that we update other data structures
3472 if (lookup_stmt_eh_region (stmt) >= 0)
3474 if (!tree_could_throw_p (stmt))
3476 error ("statement marked for throw, but doesn%'t");
3479 if (!last_in_block && tree_can_throw_internal (stmt))
3481 error ("statement marked for throw in middle of block");
3489 debug_generic_stmt (stmt);
3494 /* Return true when the T can be shared. */
3497 tree_node_can_be_shared (tree t)
3499 if (IS_TYPE_OR_DECL_P (t)
3500 || is_gimple_min_invariant (t)
3501 || TREE_CODE (t) == SSA_NAME
3502 || t == error_mark_node
3503 || TREE_CODE (t) == IDENTIFIER_NODE)
3506 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3509 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3510 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3511 || TREE_CODE (t) == COMPONENT_REF
3512 || TREE_CODE (t) == REALPART_EXPR
3513 || TREE_CODE (t) == IMAGPART_EXPR)
3514 t = TREE_OPERAND (t, 0);
3523 /* Called via walk_trees. Verify tree sharing. */
3526 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3528 htab_t htab = (htab_t) data;
3531 if (tree_node_can_be_shared (*tp))
3533 *walk_subtrees = false;
3537 slot = htab_find_slot (htab, *tp, INSERT);
3539 return (tree) *slot;
3546 /* Helper function for verify_gimple_tuples. */
3549 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3550 void *data ATTRIBUTE_UNUSED)
3552 switch (TREE_CODE (*tp))
3555 error ("unexpected non-tuple");
3565 /* Verify that there are no trees that should have been converted to
3566 gimple tuples. Return true if T contains a node that should have
3567 been converted to a gimple tuple, but hasn't. */
3570 verify_gimple_tuples (tree t)
3572 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3575 /* Verify the GIMPLE statement chain. */
3581 block_stmt_iterator bsi;
3586 timevar_push (TV_TREE_STMT_VERIFY);
3587 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3594 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3596 int phi_num_args = PHI_NUM_ARGS (phi);
3598 if (bb_for_stmt (phi) != bb)
3600 error ("bb_for_stmt (phi) is set to a wrong basic block");
3604 for (i = 0; i < phi_num_args; i++)
3606 tree t = PHI_ARG_DEF (phi, i);
3609 /* Addressable variables do have SSA_NAMEs but they
3610 are not considered gimple values. */
3611 if (TREE_CODE (t) != SSA_NAME
3612 && TREE_CODE (t) != FUNCTION_DECL
3613 && !is_gimple_val (t))
3615 error ("PHI def is not a GIMPLE value");
3616 debug_generic_stmt (phi);
3617 debug_generic_stmt (t);
3621 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3624 debug_generic_stmt (addr);
3628 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3631 error ("incorrect sharing of tree nodes");
3632 debug_generic_stmt (phi);
3633 debug_generic_stmt (addr);
3639 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3641 tree stmt = bsi_stmt (bsi);
3643 err |= verify_gimple_tuples (stmt);
3645 if (bb_for_stmt (stmt) != bb)
3647 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3652 err |= verify_stmt (stmt, bsi_end_p (bsi));
3653 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3656 error ("incorrect sharing of tree nodes");
3657 debug_generic_stmt (stmt);
3658 debug_generic_stmt (addr);
3665 internal_error ("verify_stmts failed");
3668 verify_histograms ();
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);
4340 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4342 /* Create new names for all the definitions created by COPY and
4343 add replacement mappings for each new name. */
4344 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4345 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4352 /* Basic block BB_COPY was created by code duplication. Add phi node
4353 arguments for edges going out of BB_COPY. The blocks that were
4354 duplicated have BB_DUPLICATED set. */
4357 add_phi_args_after_copy_bb (basic_block bb_copy)
4359 basic_block bb, dest;
4362 tree phi, phi_copy, phi_next, def;
4364 bb = get_bb_original (bb_copy);
4366 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4368 if (!phi_nodes (e_copy->dest))
4371 if (e_copy->dest->flags & BB_DUPLICATED)
4372 dest = get_bb_original (e_copy->dest);
4374 dest = e_copy->dest;
4376 e = find_edge (bb, dest);
4379 /* During loop unrolling the target of the latch edge is copied.
4380 In this case we are not looking for edge to dest, but to
4381 duplicated block whose original was dest. */
4382 FOR_EACH_EDGE (e, ei, bb->succs)
4383 if ((e->dest->flags & BB_DUPLICATED)
4384 && get_bb_original (e->dest) == dest)
4387 gcc_assert (e != NULL);
4390 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4392 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4394 phi_next = PHI_CHAIN (phi);
4395 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4396 add_phi_arg (phi_copy, def, e_copy);
4401 /* Blocks in REGION_COPY array of length N_REGION were created by
4402 duplication of basic blocks. Add phi node arguments for edges
4403 going from these blocks. */
4406 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4410 for (i = 0; i < n_region; i++)
4411 region_copy[i]->flags |= BB_DUPLICATED;
4413 for (i = 0; i < n_region; i++)
4414 add_phi_args_after_copy_bb (region_copy[i]);
4416 for (i = 0; i < n_region; i++)
4417 region_copy[i]->flags &= ~BB_DUPLICATED;
4420 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4421 important exit edge EXIT. By important we mean that no SSA name defined
4422 inside region is live over the other exit edges of the region. All entry
4423 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4424 to the duplicate of the region. SSA form, dominance and loop information
4425 is updated. The new basic blocks are stored to REGION_COPY in the same
4426 order as they had in REGION, provided that REGION_COPY is not NULL.
4427 The function returns false if it is unable to copy the region,
4431 tree_duplicate_sese_region (edge entry, edge exit,
4432 basic_block *region, unsigned n_region,
4433 basic_block *region_copy)
4436 bool free_region_copy = false, copying_header = false;
4437 struct loop *loop = entry->dest->loop_father;
4441 int total_freq = 0, entry_freq = 0;
4442 gcov_type total_count = 0, entry_count = 0;
4444 if (!can_copy_bbs_p (region, n_region))
4447 /* Some sanity checking. Note that we do not check for all possible
4448 missuses of the functions. I.e. if you ask to copy something weird,
4449 it will work, but the state of structures probably will not be
4451 for (i = 0; i < n_region; i++)
4453 /* We do not handle subloops, i.e. all the blocks must belong to the
4455 if (region[i]->loop_father != loop)
4458 if (region[i] != entry->dest
4459 && region[i] == loop->header)
4465 /* In case the function is used for loop header copying (which is the primary
4466 use), ensure that EXIT and its copy will be new latch and entry edges. */
4467 if (loop->header == entry->dest)
4469 copying_header = true;
4470 loop->copy = loop->outer;
4472 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4475 for (i = 0; i < n_region; i++)
4476 if (region[i] != exit->src
4477 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4483 region_copy = XNEWVEC (basic_block, n_region);
4484 free_region_copy = true;
4487 gcc_assert (!need_ssa_update_p ());
4489 /* Record blocks outside the region that are dominated by something
4491 doms = XNEWVEC (basic_block, n_basic_blocks);
4492 initialize_original_copy_tables ();
4494 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4496 if (entry->dest->count)
4498 total_count = entry->dest->count;
4499 entry_count = entry->count;
4500 /* Fix up corner cases, to avoid division by zero or creation of negative
4502 if (entry_count > total_count)
4503 entry_count = total_count;
4507 total_freq = entry->dest->frequency;
4508 entry_freq = EDGE_FREQUENCY (entry);
4509 /* Fix up corner cases, to avoid division by zero or creation of negative
4511 if (total_freq == 0)
4513 else if (entry_freq > total_freq)
4514 entry_freq = total_freq;
4517 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4518 split_edge_bb_loc (entry));
4521 scale_bbs_frequencies_gcov_type (region, n_region,
4522 total_count - entry_count,
4524 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4529 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4531 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4536 loop->header = exit->dest;
4537 loop->latch = exit->src;
4540 /* Redirect the entry and add the phi node arguments. */
4541 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4542 gcc_assert (redirected != NULL);
4543 flush_pending_stmts (entry);
4545 /* Concerning updating of dominators: We must recount dominators
4546 for entry block and its copy. Anything that is outside of the
4547 region, but was dominated by something inside needs recounting as
4549 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4550 doms[n_doms++] = get_bb_original (entry->dest);
4551 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4554 /* Add the other PHI node arguments. */
4555 add_phi_args_after_copy (region_copy, n_region);
4557 /* Update the SSA web. */
4558 update_ssa (TODO_update_ssa);
4560 if (free_region_copy)
4563 free_original_copy_tables ();
4568 DEF_VEC_P(basic_block);
4569 DEF_VEC_ALLOC_P(basic_block,heap);
4572 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4573 adding blocks when the dominator traversal reaches EXIT. This
4574 function silently assumes that ENTRY strictly dominates EXIT. */
4577 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4578 VEC(basic_block,heap) **bbs_p)
4582 for (son = first_dom_son (CDI_DOMINATORS, entry);
4584 son = next_dom_son (CDI_DOMINATORS, son))
4586 VEC_safe_push (basic_block, heap, *bbs_p, son);
4588 gather_blocks_in_sese_region (son, exit, bbs_p);
4598 bitmap vars_to_remove;
4599 htab_t new_label_map;
4603 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4604 contained in *TP and change the DECL_CONTEXT of every local
4605 variable referenced in *TP. */
4608 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4610 struct move_stmt_d *p = (struct move_stmt_d *) data;
4614 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4615 TREE_BLOCK (t) = p->block;
4617 if (OMP_DIRECTIVE_P (t)
4618 && TREE_CODE (t) != OMP_RETURN
4619 && TREE_CODE (t) != OMP_CONTINUE)
4621 /* Do not remap variables inside OMP directives. Variables
4622 referenced in clauses and directive header belong to the
4623 parent function and should not be moved into the child
4625 bool save_remap_decls_p = p->remap_decls_p;
4626 p->remap_decls_p = false;
4629 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4631 p->remap_decls_p = save_remap_decls_p;
4633 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4635 if (TREE_CODE (t) == LABEL_DECL)
4637 if (p->new_label_map)
4639 struct tree_map in, *out;
4641 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4646 DECL_CONTEXT (t) = p->to_context;
4648 else if (p->remap_decls_p)
4650 DECL_CONTEXT (t) = p->to_context;
4652 if (TREE_CODE (t) == VAR_DECL)
4654 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4655 f->unexpanded_var_list
4656 = tree_cons (0, t, f->unexpanded_var_list);
4658 /* Mark T to be removed from the original function,
4659 otherwise it will be given a DECL_RTL when the
4660 original function is expanded. */
4661 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4665 else if (TYPE_P (t))
4672 /* Move basic block BB from function CFUN to function DEST_FN. The
4673 block is moved out of the original linked list and placed after
4674 block AFTER in the new list. Also, the block is removed from the
4675 original array of blocks and placed in DEST_FN's array of blocks.
4676 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4677 updated to reflect the moved edges.
4679 On exit, local variables that need to be removed from
4680 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4683 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4684 basic_block after, bool update_edge_count_p,
4685 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4687 struct control_flow_graph *cfg;
4690 block_stmt_iterator si;
4691 struct move_stmt_d d;
4692 unsigned old_len, new_len;
4694 /* Link BB to the new linked list. */
4695 move_block_after (bb, after);
4697 /* Update the edge count in the corresponding flowgraphs. */
4698 if (update_edge_count_p)
4699 FOR_EACH_EDGE (e, ei, bb->succs)
4701 cfun->cfg->x_n_edges--;
4702 dest_cfun->cfg->x_n_edges++;
4705 /* Remove BB from the original basic block array. */
4706 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4707 cfun->cfg->x_n_basic_blocks--;
4709 /* Grow DEST_CFUN's basic block array if needed. */
4710 cfg = dest_cfun->cfg;
4711 cfg->x_n_basic_blocks++;
4712 if (bb->index > cfg->x_last_basic_block)
4713 cfg->x_last_basic_block = bb->index;
4715 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4716 if ((unsigned) cfg->x_last_basic_block >= old_len)
4718 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4719 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
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_cleared (basic_block, gc,
4757 cfg->x_label_to_block_map, new_len);
4760 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4761 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4763 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4765 if (uid >= dest_cfun->last_label_uid)
4766 dest_cfun->last_label_uid = uid + 1;
4768 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4769 TREE_OPERAND (stmt, 0) =
4770 build_int_cst (NULL_TREE,
4771 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4774 region = lookup_stmt_eh_region (stmt);
4777 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4778 remove_stmt_from_eh_region (stmt);
4779 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4780 gimple_remove_stmt_histograms (cfun, stmt);
4785 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4786 the outermost EH region. Use REGION as the incoming base EH region. */
4789 find_outermost_region_in_block (struct function *src_cfun,
4790 basic_block bb, int region)
4792 block_stmt_iterator si;
4794 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4796 tree stmt = bsi_stmt (si);
4799 if (TREE_CODE (stmt) == RESX_EXPR)
4800 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4802 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4803 if (stmt_region > 0)
4806 region = stmt_region;
4807 else if (stmt_region != region)
4809 region = eh_region_outermost (src_cfun, stmt_region, region);
4810 gcc_assert (region != -1);
4819 new_label_mapper (tree decl, void *data)
4821 htab_t hash = (htab_t) data;
4825 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4827 m = xmalloc (sizeof (struct tree_map));
4828 m->hash = DECL_UID (decl);
4830 m->to = create_artificial_label ();
4831 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4833 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4834 gcc_assert (*slot == NULL);
4841 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4842 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4843 single basic block in the original CFG and the new basic block is
4844 returned. DEST_CFUN must not have a CFG yet.
4846 Note that the region need not be a pure SESE region. Blocks inside
4847 the region may contain calls to abort/exit. The only restriction
4848 is that ENTRY_BB should be the only entry point and it must
4851 All local variables referenced in the region are assumed to be in
4852 the corresponding BLOCK_VARS and unexpanded variable lists
4853 associated with DEST_CFUN. */
4856 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4857 basic_block exit_bb)
4859 VEC(basic_block,heap) *bbs;
4860 basic_block after, bb, *entry_pred, *exit_succ;
4861 struct function *saved_cfun;
4862 int *entry_flag, *exit_flag, eh_offset;
4863 unsigned i, num_entry_edges, num_exit_edges;
4866 bitmap vars_to_remove;
4867 htab_t new_label_map;
4871 /* Collect all the blocks in the region. Manually add ENTRY_BB
4872 because it won't be added by dfs_enumerate_from. */
4873 calculate_dominance_info (CDI_DOMINATORS);
4875 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4877 gcc_assert (entry_bb != exit_bb
4879 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4882 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4883 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4885 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4886 the predecessor edges to ENTRY_BB and the successor edges to
4887 EXIT_BB so that we can re-attach them to the new basic block that
4888 will replace the region. */
4889 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4890 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4891 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4893 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4895 entry_flag[i] = e->flags;
4896 entry_pred[i++] = e->src;
4902 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4903 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4904 sizeof (basic_block));
4905 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4907 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4909 exit_flag[i] = e->flags;
4910 exit_succ[i++] = e->dest;
4921 /* Switch context to the child function to initialize DEST_FN's CFG. */
4922 gcc_assert (dest_cfun->cfg == NULL);
4925 init_empty_tree_cfg ();
4927 /* Initialize EH information for the new function. */
4929 new_label_map = NULL;
4934 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4935 region = find_outermost_region_in_block (saved_cfun, bb, region);
4937 init_eh_for_function ();
4940 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4941 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4942 new_label_map, region, 0);
4948 /* Move blocks from BBS into DEST_CFUN. */
4949 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4950 after = dest_cfun->cfg->x_entry_block_ptr;
4951 vars_to_remove = BITMAP_ALLOC (NULL);
4952 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4954 /* No need to update edge counts on the last block. It has
4955 already been updated earlier when we detached the region from
4956 the original CFG. */
4957 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4958 new_label_map, eh_offset);
4963 htab_delete (new_label_map);
4965 /* Remove the variables marked in VARS_TO_REMOVE from
4966 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4967 DECL_RTL in the context of CFUN. */
4968 if (!bitmap_empty_p (vars_to_remove))
4972 for (p = &cfun->unexpanded_var_list; *p; )
4974 tree var = TREE_VALUE (*p);
4975 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4977 *p = TREE_CHAIN (*p);
4981 p = &TREE_CHAIN (*p);
4985 BITMAP_FREE (vars_to_remove);
4987 /* Rewire the entry and exit blocks. The successor to the entry
4988 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4989 the child function. Similarly, the predecessor of DEST_FN's
4990 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4991 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4992 various CFG manipulation function get to the right CFG.
4994 FIXME, this is silly. The CFG ought to become a parameter to
4997 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4999 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
5002 /* Back in the original function, the SESE region has disappeared,
5003 create a new basic block in its place. */
5004 bb = create_empty_bb (entry_pred[0]);
5005 for (i = 0; i < num_entry_edges; i++)
5006 make_edge (entry_pred[i], bb, entry_flag[i]);
5008 for (i = 0; i < num_exit_edges; i++)
5009 make_edge (bb, exit_succ[i], exit_flag[i]);
5018 free_dominance_info (CDI_DOMINATORS);
5019 free_dominance_info (CDI_POST_DOMINATORS);
5020 VEC_free (basic_block, heap, bbs);
5026 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5029 dump_function_to_file (tree fn, FILE *file, int flags)
5031 tree arg, vars, var;
5032 bool ignore_topmost_bind = false, any_var = false;
5035 struct function *saved_cfun;
5037 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5039 arg = DECL_ARGUMENTS (fn);
5042 print_generic_expr (file, arg, dump_flags);
5043 if (TREE_CHAIN (arg))
5044 fprintf (file, ", ");
5045 arg = TREE_CHAIN (arg);
5047 fprintf (file, ")\n");
5049 if (flags & TDF_DETAILS)
5050 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5051 if (flags & TDF_RAW)
5053 dump_node (fn, TDF_SLIM | flags, file);
5057 /* Switch CFUN to point to FN. */
5059 cfun = DECL_STRUCT_FUNCTION (fn);
5061 /* When GIMPLE is lowered, the variables are no longer available in
5062 BIND_EXPRs, so display them separately. */
5063 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5065 ignore_topmost_bind = true;
5067 fprintf (file, "{\n");
5068 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5070 var = TREE_VALUE (vars);
5072 print_generic_decl (file, var, flags);
5073 fprintf (file, "\n");
5079 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5081 /* Make a CFG based dump. */
5082 check_bb_profile (ENTRY_BLOCK_PTR, file);
5083 if (!ignore_topmost_bind)
5084 fprintf (file, "{\n");
5086 if (any_var && n_basic_blocks)
5087 fprintf (file, "\n");
5090 dump_generic_bb (file, bb, 2, flags);
5092 fprintf (file, "}\n");
5093 check_bb_profile (EXIT_BLOCK_PTR, file);
5099 /* Make a tree based dump. */
5100 chain = DECL_SAVED_TREE (fn);
5102 if (chain && TREE_CODE (chain) == BIND_EXPR)
5104 if (ignore_topmost_bind)
5106 chain = BIND_EXPR_BODY (chain);
5114 if (!ignore_topmost_bind)
5115 fprintf (file, "{\n");
5120 fprintf (file, "\n");
5122 print_generic_stmt_indented (file, chain, flags, indent);
5123 if (ignore_topmost_bind)
5124 fprintf (file, "}\n");
5127 fprintf (file, "\n\n");
5134 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5137 debug_function (tree fn, int flags)
5139 dump_function_to_file (fn, stderr, flags);
5143 /* Pretty print of the loops intermediate representation. */
5144 static void print_loop (FILE *, struct loop *, int);
5145 static void print_pred_bbs (FILE *, basic_block bb);
5146 static void print_succ_bbs (FILE *, basic_block bb);
5149 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5152 print_pred_bbs (FILE *file, basic_block bb)
5157 FOR_EACH_EDGE (e, ei, bb->preds)
5158 fprintf (file, "bb_%d ", e->src->index);
5162 /* Print on FILE the indexes for the successors of basic_block BB. */
5165 print_succ_bbs (FILE *file, basic_block bb)
5170 FOR_EACH_EDGE (e, ei, bb->succs)
5171 fprintf (file, "bb_%d ", e->dest->index);
5175 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5178 print_loop (FILE *file, struct loop *loop, int indent)
5186 s_indent = (char *) alloca ((size_t) indent + 1);
5187 memset ((void *) s_indent, ' ', (size_t) indent);
5188 s_indent[indent] = '\0';
5190 /* Print the loop's header. */
5191 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5193 /* Print the loop's body. */
5194 fprintf (file, "%s{\n", s_indent);
5196 if (bb->loop_father == loop)
5198 /* Print the basic_block's header. */
5199 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5200 print_pred_bbs (file, bb);
5201 fprintf (file, "}, succs = {");
5202 print_succ_bbs (file, bb);
5203 fprintf (file, "})\n");
5205 /* Print the basic_block's body. */
5206 fprintf (file, "%s {\n", s_indent);
5207 tree_dump_bb (bb, file, indent + 4);
5208 fprintf (file, "%s }\n", s_indent);
5211 print_loop (file, loop->inner, indent + 2);
5212 fprintf (file, "%s}\n", s_indent);
5213 print_loop (file, loop->next, indent);
5217 /* Follow a CFG edge from the entry point of the program, and on entry
5218 of a loop, pretty print the loop structure on FILE. */
5221 print_loop_ir (FILE *file)
5225 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5226 if (bb && bb->loop_father)
5227 print_loop (file, bb->loop_father, 0);
5231 /* Debugging loops structure at tree level. */
5234 debug_loop_ir (void)
5236 print_loop_ir (stderr);
5240 /* Return true if BB ends with a call, possibly followed by some
5241 instructions that must stay with the call. Return false,
5245 tree_block_ends_with_call_p (basic_block bb)
5247 block_stmt_iterator bsi = bsi_last (bb);
5248 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5252 /* Return true if BB ends with a conditional branch. Return false,
5256 tree_block_ends_with_condjump_p (basic_block bb)
5258 tree stmt = last_stmt (bb);
5259 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5263 /* Return true if we need to add fake edge to exit at statement T.
5264 Helper function for tree_flow_call_edges_add. */
5267 need_fake_edge_p (tree t)
5271 /* NORETURN and LONGJMP calls already have an edge to exit.
5272 CONST and PURE calls do not need one.
5273 We don't currently check for CONST and PURE here, although
5274 it would be a good idea, because those attributes are
5275 figured out from the RTL in mark_constant_function, and
5276 the counter incrementation code from -fprofile-arcs
5277 leads to different results from -fbranch-probabilities. */
5278 call = get_call_expr_in (t);
5280 && !(call_expr_flags (call) & ECF_NORETURN))
5283 if (TREE_CODE (t) == ASM_EXPR
5284 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5291 /* Add fake edges to the function exit for any non constant and non
5292 noreturn calls, volatile inline assembly in the bitmap of blocks
5293 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5294 the number of blocks that were split.
5296 The goal is to expose cases in which entering a basic block does
5297 not imply that all subsequent instructions must be executed. */
5300 tree_flow_call_edges_add (sbitmap blocks)
5303 int blocks_split = 0;
5304 int last_bb = last_basic_block;
5305 bool check_last_block = false;
5307 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5311 check_last_block = true;
5313 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5315 /* In the last basic block, before epilogue generation, there will be
5316 a fallthru edge to EXIT. Special care is required if the last insn
5317 of the last basic block is a call because make_edge folds duplicate
5318 edges, which would result in the fallthru edge also being marked
5319 fake, which would result in the fallthru edge being removed by
5320 remove_fake_edges, which would result in an invalid CFG.
5322 Moreover, we can't elide the outgoing fake edge, since the block
5323 profiler needs to take this into account in order to solve the minimal
5324 spanning tree in the case that the call doesn't return.
5326 Handle this by adding a dummy instruction in a new last basic block. */
5327 if (check_last_block)
5329 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5330 block_stmt_iterator bsi = bsi_last (bb);
5332 if (!bsi_end_p (bsi))
5335 if (t && need_fake_edge_p (t))
5339 e = find_edge (bb, EXIT_BLOCK_PTR);
5342 bsi_insert_on_edge (e, build_empty_stmt ());
5343 bsi_commit_edge_inserts ();
5348 /* Now add fake edges to the function exit for any non constant
5349 calls since there is no way that we can determine if they will
5351 for (i = 0; i < last_bb; i++)
5353 basic_block bb = BASIC_BLOCK (i);
5354 block_stmt_iterator bsi;
5355 tree stmt, last_stmt;
5360 if (blocks && !TEST_BIT (blocks, i))
5363 bsi = bsi_last (bb);
5364 if (!bsi_end_p (bsi))
5366 last_stmt = bsi_stmt (bsi);
5369 stmt = bsi_stmt (bsi);
5370 if (need_fake_edge_p (stmt))
5373 /* The handling above of the final block before the
5374 epilogue should be enough to verify that there is
5375 no edge to the exit block in CFG already.
5376 Calling make_edge in such case would cause us to
5377 mark that edge as fake and remove it later. */
5378 #ifdef ENABLE_CHECKING
5379 if (stmt == last_stmt)
5381 e = find_edge (bb, EXIT_BLOCK_PTR);
5382 gcc_assert (e == NULL);
5386 /* Note that the following may create a new basic block
5387 and renumber the existing basic blocks. */
5388 if (stmt != last_stmt)
5390 e = split_block (bb, stmt);
5394 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5398 while (!bsi_end_p (bsi));
5403 verify_flow_info ();
5405 return blocks_split;
5408 /* Purge dead abnormal call edges from basic block BB. */
5411 tree_purge_dead_abnormal_call_edges (basic_block bb)
5413 bool changed = tree_purge_dead_eh_edges (bb);
5415 if (current_function_has_nonlocal_label)
5417 tree stmt = last_stmt (bb);
5421 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5422 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5424 if (e->flags & EDGE_ABNORMAL)
5433 /* See tree_purge_dead_eh_edges below. */
5435 free_dominance_info (CDI_DOMINATORS);
5441 /* Purge dead EH edges from basic block BB. */
5444 tree_purge_dead_eh_edges (basic_block bb)
5446 bool changed = false;
5449 tree stmt = last_stmt (bb);
5451 if (stmt && tree_can_throw_internal (stmt))
5454 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5456 if (e->flags & EDGE_EH)
5465 /* Removal of dead EH edges might change dominators of not
5466 just immediate successors. E.g. when bb1 is changed so that
5467 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5468 eh edges purged by this function in:
5480 idom(bb5) must be recomputed. For now just free the dominance
5483 free_dominance_info (CDI_DOMINATORS);
5489 tree_purge_all_dead_eh_edges (bitmap blocks)
5491 bool changed = false;
5495 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5497 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5503 /* This function is called whenever a new edge is created or
5507 tree_execute_on_growing_pred (edge e)
5509 basic_block bb = e->dest;
5512 reserve_phi_args_for_new_edge (bb);
5515 /* This function is called immediately before edge E is removed from
5516 the edge vector E->dest->preds. */
5519 tree_execute_on_shrinking_pred (edge e)
5521 if (phi_nodes (e->dest))
5522 remove_phi_args (e);
5525 /*---------------------------------------------------------------------------
5526 Helper functions for Loop versioning
5527 ---------------------------------------------------------------------------*/
5529 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5530 of 'first'. Both of them are dominated by 'new_head' basic block. When
5531 'new_head' was created by 'second's incoming edge it received phi arguments
5532 on the edge by split_edge(). Later, additional edge 'e' was created to
5533 connect 'new_head' and 'first'. Now this routine adds phi args on this
5534 additional edge 'e' that new_head to second edge received as part of edge
5539 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5540 basic_block new_head, edge e)
5543 edge e2 = find_edge (new_head, second);
5545 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5546 edge, we should always have an edge from NEW_HEAD to SECOND. */
5547 gcc_assert (e2 != NULL);
5549 /* Browse all 'second' basic block phi nodes and add phi args to
5550 edge 'e' for 'first' head. PHI args are always in correct order. */
5552 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5554 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5556 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5557 add_phi_arg (phi1, def, e);
5561 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5562 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5563 the destination of the ELSE part. */
5565 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5566 basic_block cond_bb, void *cond_e)
5568 block_stmt_iterator bsi;
5569 tree goto1 = NULL_TREE;
5570 tree goto2 = NULL_TREE;
5571 tree new_cond_expr = NULL_TREE;
5572 tree cond_expr = (tree) cond_e;
5575 /* Build new conditional expr */
5576 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5577 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5578 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5580 /* Add new cond in cond_bb. */
5581 bsi = bsi_start (cond_bb);
5582 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5583 /* Adjust edges appropriately to connect new head with first head
5584 as well as second head. */
5585 e0 = single_succ_edge (cond_bb);
5586 e0->flags &= ~EDGE_FALLTHRU;
5587 e0->flags |= EDGE_FALSE_VALUE;
5590 struct cfg_hooks tree_cfg_hooks = {
5592 tree_verify_flow_info,
5593 tree_dump_bb, /* dump_bb */
5594 create_bb, /* create_basic_block */
5595 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5596 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5597 remove_bb, /* delete_basic_block */
5598 tree_split_block, /* split_block */
5599 tree_move_block_after, /* move_block_after */
5600 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5601 tree_merge_blocks, /* merge_blocks */
5602 tree_predict_edge, /* predict_edge */
5603 tree_predicted_by_p, /* predicted_by_p */
5604 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5605 tree_duplicate_bb, /* duplicate_block */
5606 tree_split_edge, /* split_edge */
5607 tree_make_forwarder_block, /* make_forward_block */
5608 NULL, /* tidy_fallthru_edge */
5609 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5610 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5611 tree_flow_call_edges_add, /* flow_call_edges_add */
5612 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5613 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5614 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5615 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5616 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5617 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5618 flush_pending_stmts /* flush_pending_stmts */
5622 /* Split all critical edges. */
5625 split_critical_edges (void)
5631 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5632 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5633 mappings around the calls to split_edge. */
5634 start_recording_case_labels ();
5637 FOR_EACH_EDGE (e, ei, bb->succs)
5638 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5643 end_recording_case_labels ();
5647 struct tree_opt_pass pass_split_crit_edges =
5649 "crited", /* name */
5651 split_critical_edges, /* execute */
5654 0, /* static_pass_number */
5655 TV_TREE_SPLIT_EDGES, /* tv_id */
5656 PROP_cfg, /* properties required */
5657 PROP_no_crit_edges, /* properties_provided */
5658 0, /* properties_destroyed */
5659 0, /* todo_flags_start */
5660 TODO_dump_func, /* todo_flags_finish */
5665 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5666 a temporary, make sure and register it to be renamed if necessary,
5667 and finally return the temporary. Put the statements to compute
5668 EXP before the current statement in BSI. */
5671 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5673 tree t, new_stmt, orig_stmt;
5675 if (is_gimple_val (exp))
5678 t = make_rename_temp (type, NULL);
5679 new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, t, exp);
5681 orig_stmt = bsi_stmt (*bsi);
5682 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5683 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5685 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5686 if (gimple_in_ssa_p (cfun))
5687 mark_symbols_for_renaming (new_stmt);
5692 /* Build a ternary operation and gimplify it. Emit code before BSI.
5693 Return the gimple_val holding the result. */
5696 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5697 tree type, tree a, tree b, tree c)
5701 ret = fold_build3 (code, type, a, b, c);
5704 return gimplify_val (bsi, type, ret);
5707 /* Build a binary operation and gimplify it. Emit code before BSI.
5708 Return the gimple_val holding the result. */
5711 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5712 tree type, tree a, tree b)
5716 ret = fold_build2 (code, type, a, b);
5719 return gimplify_val (bsi, type, ret);
5722 /* Build a unary operation and gimplify it. Emit code before BSI.
5723 Return the gimple_val holding the result. */
5726 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5731 ret = fold_build1 (code, type, a);
5734 return gimplify_val (bsi, type, ret);
5739 /* Emit return warnings. */
5742 execute_warn_function_return (void)
5744 #ifdef USE_MAPPED_LOCATION
5745 source_location location;
5753 /* If we have a path to EXIT, then we do return. */
5754 if (TREE_THIS_VOLATILE (cfun->decl)
5755 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5757 #ifdef USE_MAPPED_LOCATION
5758 location = UNKNOWN_LOCATION;
5762 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5764 last = last_stmt (e->src);
5765 if (TREE_CODE (last) == RETURN_EXPR
5766 #ifdef USE_MAPPED_LOCATION
5767 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5769 && (locus = EXPR_LOCUS (last)) != NULL)
5773 #ifdef USE_MAPPED_LOCATION
5774 if (location == UNKNOWN_LOCATION)
5775 location = cfun->function_end_locus;
5776 warning (0, "%H%<noreturn%> function does return", &location);
5779 locus = &cfun->function_end_locus;
5780 warning (0, "%H%<noreturn%> function does return", locus);
5784 /* If we see "return;" in some basic block, then we do reach the end
5785 without returning a value. */
5786 else if (warn_return_type
5787 && !TREE_NO_WARNING (cfun->decl)
5788 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5789 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5791 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5793 tree last = last_stmt (e->src);
5794 if (TREE_CODE (last) == RETURN_EXPR
5795 && TREE_OPERAND (last, 0) == NULL
5796 && !TREE_NO_WARNING (last))
5798 #ifdef USE_MAPPED_LOCATION
5799 location = EXPR_LOCATION (last);
5800 if (location == UNKNOWN_LOCATION)
5801 location = cfun->function_end_locus;
5802 warning (0, "%Hcontrol reaches end of non-void function", &location);
5804 locus = EXPR_LOCUS (last);
5806 locus = &cfun->function_end_locus;
5807 warning (0, "%Hcontrol reaches end of non-void function", locus);
5809 TREE_NO_WARNING (cfun->decl) = 1;
5818 /* Given a basic block B which ends with a conditional and has
5819 precisely two successors, determine which of the edges is taken if
5820 the conditional is true and which is taken if the conditional is
5821 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5824 extract_true_false_edges_from_block (basic_block b,
5828 edge e = EDGE_SUCC (b, 0);
5830 if (e->flags & EDGE_TRUE_VALUE)
5833 *false_edge = EDGE_SUCC (b, 1);
5838 *true_edge = EDGE_SUCC (b, 1);
5842 struct tree_opt_pass pass_warn_function_return =
5846 execute_warn_function_return, /* execute */
5849 0, /* static_pass_number */
5851 PROP_cfg, /* properties_required */
5852 0, /* properties_provided */
5853 0, /* properties_destroyed */
5854 0, /* todo_flags_start */
5855 0, /* todo_flags_finish */
5859 /* Emit noreturn warnings. */
5862 execute_warn_function_noreturn (void)
5864 if (warn_missing_noreturn
5865 && !TREE_THIS_VOLATILE (cfun->decl)
5866 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5867 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5868 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5869 "for attribute %<noreturn%>",
5874 struct tree_opt_pass pass_warn_function_noreturn =
5878 execute_warn_function_noreturn, /* execute */
5881 0, /* static_pass_number */
5883 PROP_cfg, /* properties_required */
5884 0, /* properties_provided */
5885 0, /* properties_destroyed */
5886 0, /* todo_flags_start */
5887 0, /* todo_flags_finish */