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"
50 #include "pointer-set.h"
52 /* This file contains functions for building the Control Flow Graph (CFG)
53 for a function tree. */
55 /* Local declarations. */
57 /* Initial capacity for the basic block array. */
58 static const int initial_cfg_capacity = 20;
60 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
61 which use a particular edge. The CASE_LABEL_EXPRs are chained together
62 via their TREE_CHAIN field, which we clear after we're done with the
63 hash table to prevent problems with duplication of SWITCH_EXPRs.
65 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
66 update the case vector in response to edge redirections.
68 Right now this table is set up and torn down at key points in the
69 compilation process. It would be nice if we could make the table
70 more persistent. The key is getting notification of changes to
71 the CFG (particularly edge removal, creation and redirection). */
73 struct edge_to_cases_elt
75 /* The edge itself. Necessary for hashing and equality tests. */
78 /* The case labels associated with this edge. We link these up via
79 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
80 when we destroy the hash table. This prevents problems when copying
85 static htab_t edge_to_cases;
90 long num_merged_labels;
93 static struct cfg_stats_d cfg_stats;
95 /* Nonzero if we found a computed goto while building basic blocks. */
96 static bool found_computed_goto;
98 /* Basic blocks and flowgraphs. */
99 static basic_block create_bb (void *, void *, basic_block);
100 static void make_blocks (tree);
101 static void factor_computed_gotos (void);
104 static void make_edges (void);
105 static void make_cond_expr_edges (basic_block);
106 static void make_switch_expr_edges (basic_block);
107 static void make_goto_expr_edges (basic_block);
108 static edge tree_redirect_edge_and_branch (edge, basic_block);
109 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
110 static unsigned int split_critical_edges (void);
112 /* Various helpers. */
113 static inline bool stmt_starts_bb_p (tree, tree);
114 static int tree_verify_flow_info (void);
115 static void tree_make_forwarder_block (edge);
116 static void tree_cfg2vcg (FILE *);
117 static inline void change_bb_for_stmt (tree t, basic_block bb);
119 /* Flowgraph optimization and cleanup. */
120 static void tree_merge_blocks (basic_block, basic_block);
121 static bool tree_can_merge_blocks_p (basic_block, basic_block);
122 static void remove_bb (basic_block);
123 static edge find_taken_edge_computed_goto (basic_block, tree);
124 static edge find_taken_edge_cond_expr (basic_block, tree);
125 static edge find_taken_edge_switch_expr (basic_block, tree);
126 static tree find_case_label_for_value (tree, tree);
129 init_empty_tree_cfg (void)
131 /* Initialize the basic block array. */
133 profile_status = PROFILE_ABSENT;
134 n_basic_blocks = NUM_FIXED_BLOCKS;
135 last_basic_block = NUM_FIXED_BLOCKS;
136 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
137 VEC_safe_grow_cleared (basic_block, gc, basic_block_info,
138 initial_cfg_capacity);
140 /* Build a mapping of labels to their associated blocks. */
141 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
142 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
143 initial_cfg_capacity);
145 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
146 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
147 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
148 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
151 /*---------------------------------------------------------------------------
153 ---------------------------------------------------------------------------*/
155 /* Entry point to the CFG builder for trees. TP points to the list of
156 statements to be added to the flowgraph. */
159 build_tree_cfg (tree *tp)
161 /* Register specific tree functions. */
162 tree_register_cfg_hooks ();
164 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
166 init_empty_tree_cfg ();
168 found_computed_goto = 0;
171 /* Computed gotos are hell to deal with, especially if there are
172 lots of them with a large number of destinations. So we factor
173 them to a common computed goto location before we build the
174 edge list. After we convert back to normal form, we will un-factor
175 the computed gotos since factoring introduces an unwanted jump. */
176 if (found_computed_goto)
177 factor_computed_gotos ();
179 /* Make sure there is always at least one block, even if it's empty. */
180 if (n_basic_blocks == NUM_FIXED_BLOCKS)
181 create_empty_bb (ENTRY_BLOCK_PTR);
183 /* Adjust the size of the array. */
184 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
185 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, n_basic_blocks);
187 /* To speed up statement iterator walks, we first purge dead labels. */
188 cleanup_dead_labels ();
190 /* Group case nodes to reduce the number of edges.
191 We do this after cleaning up dead labels because otherwise we miss
192 a lot of obvious case merging opportunities. */
193 group_case_labels ();
195 /* Create the edges of the flowgraph. */
198 /* Debugging dumps. */
200 /* Write the flowgraph to a VCG file. */
202 int local_dump_flags;
203 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
206 tree_cfg2vcg (vcg_file);
207 dump_end (TDI_vcg, vcg_file);
211 #ifdef ENABLE_CHECKING
215 /* Dump a textual representation of the flowgraph. */
217 dump_tree_cfg (dump_file, dump_flags);
221 execute_build_cfg (void)
223 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
227 struct tree_opt_pass pass_build_cfg =
231 execute_build_cfg, /* execute */
234 0, /* static_pass_number */
235 TV_TREE_CFG, /* tv_id */
236 PROP_gimple_leh, /* properties_required */
237 PROP_cfg, /* properties_provided */
238 0, /* properties_destroyed */
239 0, /* todo_flags_start */
240 TODO_verify_stmts | TODO_cleanup_cfg, /* todo_flags_finish */
244 /* Search the CFG for any computed gotos. If found, factor them to a
245 common computed goto site. Also record the location of that site so
246 that we can un-factor the gotos after we have converted back to
250 factor_computed_gotos (void)
253 tree factored_label_decl = NULL;
255 tree factored_computed_goto_label = NULL;
256 tree factored_computed_goto = NULL;
258 /* We know there are one or more computed gotos in this function.
259 Examine the last statement in each basic block to see if the block
260 ends with a computed goto. */
264 block_stmt_iterator bsi = bsi_last (bb);
269 last = bsi_stmt (bsi);
271 /* Ignore the computed goto we create when we factor the original
273 if (last == factored_computed_goto)
276 /* If the last statement is a computed goto, factor it. */
277 if (computed_goto_p (last))
281 /* The first time we find a computed goto we need to create
282 the factored goto block and the variable each original
283 computed goto will use for their goto destination. */
284 if (! factored_computed_goto)
286 basic_block new_bb = create_empty_bb (bb);
287 block_stmt_iterator new_bsi = bsi_start (new_bb);
289 /* Create the destination of the factored goto. Each original
290 computed goto will put its desired destination into this
291 variable and jump to the label we create immediately
293 var = create_tmp_var (ptr_type_node, "gotovar");
295 /* Build a label for the new block which will contain the
296 factored computed goto. */
297 factored_label_decl = create_artificial_label ();
298 factored_computed_goto_label
299 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
300 bsi_insert_after (&new_bsi, factored_computed_goto_label,
303 /* Build our new computed goto. */
304 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
305 bsi_insert_after (&new_bsi, factored_computed_goto,
309 /* Copy the original computed goto's destination into VAR. */
310 assignment = build2_gimple (GIMPLE_MODIFY_STMT,
311 var, GOTO_DESTINATION (last));
312 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
314 /* And re-vector the computed goto to the new destination. */
315 GOTO_DESTINATION (last) = factored_label_decl;
321 /* Build a flowgraph for the statement_list STMT_LIST. */
324 make_blocks (tree stmt_list)
326 tree_stmt_iterator i = tsi_start (stmt_list);
328 bool start_new_block = true;
329 bool first_stmt_of_list = true;
330 basic_block bb = ENTRY_BLOCK_PTR;
332 while (!tsi_end_p (i))
339 /* If the statement starts a new basic block or if we have determined
340 in a previous pass that we need to create a new block for STMT, do
342 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
344 if (!first_stmt_of_list)
345 stmt_list = tsi_split_statement_list_before (&i);
346 bb = create_basic_block (stmt_list, NULL, bb);
347 start_new_block = false;
350 /* Now add STMT to BB and create the subgraphs for special statement
352 set_bb_for_stmt (stmt, bb);
354 if (computed_goto_p (stmt))
355 found_computed_goto = true;
357 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
359 if (stmt_ends_bb_p (stmt))
360 start_new_block = true;
363 first_stmt_of_list = false;
368 /* Create and return a new empty basic block after bb AFTER. */
371 create_bb (void *h, void *e, basic_block after)
377 /* Create and initialize a new basic block. Since alloc_block uses
378 ggc_alloc_cleared to allocate a basic block, we do not have to
379 clear the newly allocated basic block here. */
382 bb->index = last_basic_block;
384 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
386 /* Add the new block to the linked list of blocks. */
387 link_block (bb, after);
389 /* Grow the basic block array if needed. */
390 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
392 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
393 VEC_safe_grow_cleared (basic_block, gc, basic_block_info, new_size);
396 /* Add the newly created block to the array. */
397 SET_BASIC_BLOCK (last_basic_block, bb);
406 /*---------------------------------------------------------------------------
408 ---------------------------------------------------------------------------*/
410 /* Fold COND_EXPR_COND of each COND_EXPR. */
413 fold_cond_expr_cond (void)
419 tree stmt = last_stmt (bb);
422 && TREE_CODE (stmt) == COND_EXPR)
424 tree cond = fold (COND_EXPR_COND (stmt));
425 if (integer_zerop (cond))
426 COND_EXPR_COND (stmt) = boolean_false_node;
427 else if (integer_onep (cond))
428 COND_EXPR_COND (stmt) = boolean_true_node;
433 /* Join all the blocks in the flowgraph. */
439 struct omp_region *cur_region = NULL;
441 /* Create an edge from entry to the first block with executable
443 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
445 /* Traverse the basic block array placing edges. */
448 tree last = last_stmt (bb);
453 enum tree_code code = TREE_CODE (last);
457 make_goto_expr_edges (bb);
461 make_edge (bb, EXIT_BLOCK_PTR, 0);
465 make_cond_expr_edges (bb);
469 make_switch_expr_edges (bb);
473 make_eh_edges (last);
478 /* If this function receives a nonlocal goto, then we need to
479 make edges from this call site to all the nonlocal goto
481 if (tree_can_make_abnormal_goto (last))
482 make_abnormal_goto_edges (bb, true);
484 /* If this statement has reachable exception handlers, then
485 create abnormal edges to them. */
486 make_eh_edges (last);
488 /* Some calls are known not to return. */
489 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
495 case GIMPLE_MODIFY_STMT:
496 if (is_ctrl_altering_stmt (last))
498 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
499 the CALL_EXPR may have an abnormal edge. Search the RHS
500 for this case and create any required edges. */
501 if (tree_can_make_abnormal_goto (last))
502 make_abnormal_goto_edges (bb, true);
504 make_eh_edges (last);
516 cur_region = new_omp_region (bb, code, cur_region);
521 cur_region = new_omp_region (bb, code, cur_region);
526 /* In the case of an OMP_SECTION, the edge will go somewhere
527 other than the next block. This will be created later. */
528 cur_region->exit = bb;
529 fallthru = cur_region->type != OMP_SECTION;
530 cur_region = cur_region->outer;
534 cur_region->cont = bb;
535 switch (cur_region->type)
538 /* ??? Technically there should be a some sort of loopback
539 edge here, but it goes to a block that doesn't exist yet,
540 and without it, updating the ssa form would be a real
541 bear. Fortunately, we don't yet do ssa before expanding
546 /* Wire up the edges into and out of the nested sections. */
547 /* ??? Similarly wrt loopback. */
549 struct omp_region *i;
550 for (i = cur_region->inner; i ; i = i->next)
552 gcc_assert (i->type == OMP_SECTION);
553 make_edge (cur_region->entry, i->entry, 0);
554 make_edge (i->exit, bb, EDGE_FALLTHRU);
566 gcc_assert (!stmt_ends_bb_p (last));
574 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
580 /* Fold COND_EXPR_COND of each COND_EXPR. */
581 fold_cond_expr_cond ();
585 /* Create the edges for a COND_EXPR starting at block BB.
586 At this point, both clauses must contain only simple gotos. */
589 make_cond_expr_edges (basic_block bb)
591 tree entry = last_stmt (bb);
592 basic_block then_bb, else_bb;
593 tree then_label, else_label;
597 gcc_assert (TREE_CODE (entry) == COND_EXPR);
599 /* Entry basic blocks for each component. */
600 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
601 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
602 then_bb = label_to_block (then_label);
603 else_bb = label_to_block (else_label);
605 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
606 #ifdef USE_MAPPED_LOCATION
607 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
609 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
611 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
614 #ifdef USE_MAPPED_LOCATION
615 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
617 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
622 /* Hashing routine for EDGE_TO_CASES. */
625 edge_to_cases_hash (const void *p)
627 edge e = ((struct edge_to_cases_elt *)p)->e;
629 /* Hash on the edge itself (which is a pointer). */
630 return htab_hash_pointer (e);
633 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
634 for equality is just a pointer comparison. */
637 edge_to_cases_eq (const void *p1, const void *p2)
639 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
640 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
645 /* Called for each element in the hash table (P) as we delete the
646 edge to cases hash table.
648 Clear all the TREE_CHAINs to prevent problems with copying of
649 SWITCH_EXPRs and structure sharing rules, then free the hash table
653 edge_to_cases_cleanup (void *p)
655 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
658 for (t = elt->case_labels; t; t = next)
660 next = TREE_CHAIN (t);
661 TREE_CHAIN (t) = NULL;
666 /* Start recording information mapping edges to case labels. */
669 start_recording_case_labels (void)
671 gcc_assert (edge_to_cases == NULL);
673 edge_to_cases = htab_create (37,
676 edge_to_cases_cleanup);
679 /* Return nonzero if we are recording information for case labels. */
682 recording_case_labels_p (void)
684 return (edge_to_cases != NULL);
687 /* Stop recording information mapping edges to case labels and
688 remove any information we have recorded. */
690 end_recording_case_labels (void)
692 htab_delete (edge_to_cases);
693 edge_to_cases = NULL;
696 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
699 record_switch_edge (edge e, tree case_label)
701 struct edge_to_cases_elt *elt;
704 /* Build a hash table element so we can see if E is already
706 elt = XNEW (struct edge_to_cases_elt);
708 elt->case_labels = case_label;
710 slot = htab_find_slot (edge_to_cases, elt, INSERT);
714 /* E was not in the hash table. Install E into the hash table. */
719 /* E was already in the hash table. Free ELT as we do not need it
723 /* Get the entry stored in the hash table. */
724 elt = (struct edge_to_cases_elt *) *slot;
726 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
727 TREE_CHAIN (case_label) = elt->case_labels;
728 elt->case_labels = case_label;
732 /* If we are inside a {start,end}_recording_cases block, then return
733 a chain of CASE_LABEL_EXPRs from T which reference E.
735 Otherwise return NULL. */
738 get_cases_for_edge (edge e, tree t)
740 struct edge_to_cases_elt elt, *elt_p;
745 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
746 chains available. Return NULL so the caller can detect this case. */
747 if (!recording_case_labels_p ())
752 elt.case_labels = NULL;
753 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
757 elt_p = (struct edge_to_cases_elt *)*slot;
758 return elt_p->case_labels;
761 /* If we did not find E in the hash table, then this must be the first
762 time we have been queried for information about E & T. Add all the
763 elements from T to the hash table then perform the query again. */
765 vec = SWITCH_LABELS (t);
766 n = TREE_VEC_LENGTH (vec);
767 for (i = 0; i < n; i++)
769 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
770 basic_block label_bb = label_to_block (lab);
771 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
776 /* Create the edges for a SWITCH_EXPR starting at block BB.
777 At this point, the switch body has been lowered and the
778 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
781 make_switch_expr_edges (basic_block bb)
783 tree entry = last_stmt (bb);
787 vec = SWITCH_LABELS (entry);
788 n = TREE_VEC_LENGTH (vec);
790 for (i = 0; i < n; ++i)
792 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
793 basic_block label_bb = label_to_block (lab);
794 make_edge (bb, label_bb, 0);
799 /* Return the basic block holding label DEST. */
802 label_to_block_fn (struct function *ifun, tree dest)
804 int uid = LABEL_DECL_UID (dest);
806 /* We would die hard when faced by an undefined label. Emit a label to
807 the very first basic block. This will hopefully make even the dataflow
808 and undefined variable warnings quite right. */
809 if ((errorcount || sorrycount) && uid < 0)
811 block_stmt_iterator bsi =
812 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
815 stmt = build1 (LABEL_EXPR, void_type_node, dest);
816 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
817 uid = LABEL_DECL_UID (dest);
819 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
820 <= (unsigned int) uid)
822 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
825 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
826 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
829 make_abnormal_goto_edges (basic_block bb, bool for_call)
831 basic_block target_bb;
832 block_stmt_iterator bsi;
834 FOR_EACH_BB (target_bb)
835 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
837 tree target = bsi_stmt (bsi);
839 if (TREE_CODE (target) != LABEL_EXPR)
842 target = LABEL_EXPR_LABEL (target);
844 /* Make an edge to every label block that has been marked as a
845 potential target for a computed goto or a non-local goto. */
846 if ((FORCED_LABEL (target) && !for_call)
847 || (DECL_NONLOCAL (target) && for_call))
849 make_edge (bb, target_bb, EDGE_ABNORMAL);
855 /* Create edges for a goto statement at block BB. */
858 make_goto_expr_edges (basic_block bb)
860 block_stmt_iterator last = bsi_last (bb);
861 tree goto_t = bsi_stmt (last);
863 /* A simple GOTO creates normal edges. */
864 if (simple_goto_p (goto_t))
866 tree dest = GOTO_DESTINATION (goto_t);
867 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
868 #ifdef USE_MAPPED_LOCATION
869 e->goto_locus = EXPR_LOCATION (goto_t);
871 e->goto_locus = EXPR_LOCUS (goto_t);
873 bsi_remove (&last, true);
877 /* A computed GOTO creates abnormal edges. */
878 make_abnormal_goto_edges (bb, false);
882 /*---------------------------------------------------------------------------
884 ---------------------------------------------------------------------------*/
886 /* Cleanup useless labels in basic blocks. This is something we wish
887 to do early because it allows us to group case labels before creating
888 the edges for the CFG, and it speeds up block statement iterators in
890 We only run this pass once, running it more than once is probably not
893 /* A map from basic block index to the leading label of that block. */
894 static tree *label_for_bb;
896 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
898 update_eh_label (struct eh_region *region)
900 tree old_label = get_eh_region_tree_label (region);
904 basic_block bb = label_to_block (old_label);
906 /* ??? After optimizing, there may be EH regions with labels
907 that have already been removed from the function body, so
908 there is no basic block for them. */
912 new_label = label_for_bb[bb->index];
913 set_eh_region_tree_label (region, new_label);
917 /* Given LABEL return the first label in the same basic block. */
919 main_block_label (tree label)
921 basic_block bb = label_to_block (label);
923 /* label_to_block possibly inserted undefined label into the chain. */
924 if (!label_for_bb[bb->index])
925 label_for_bb[bb->index] = label;
926 return label_for_bb[bb->index];
929 /* Cleanup redundant labels. This is a three-step process:
930 1) Find the leading label for each block.
931 2) Redirect all references to labels to the leading labels.
932 3) Cleanup all useless labels. */
935 cleanup_dead_labels (void)
938 label_for_bb = XCNEWVEC (tree, last_basic_block);
940 /* Find a suitable label for each block. We use the first user-defined
941 label if there is one, or otherwise just the first label we see. */
944 block_stmt_iterator i;
946 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
948 tree label, stmt = bsi_stmt (i);
950 if (TREE_CODE (stmt) != LABEL_EXPR)
953 label = LABEL_EXPR_LABEL (stmt);
955 /* If we have not yet seen a label for the current block,
956 remember this one and see if there are more labels. */
957 if (! label_for_bb[bb->index])
959 label_for_bb[bb->index] = label;
963 /* If we did see a label for the current block already, but it
964 is an artificially created label, replace it if the current
965 label is a user defined label. */
966 if (! DECL_ARTIFICIAL (label)
967 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
969 label_for_bb[bb->index] = label;
975 /* Now redirect all jumps/branches to the selected label.
976 First do so for each block ending in a control statement. */
979 tree stmt = last_stmt (bb);
983 switch (TREE_CODE (stmt))
987 tree true_branch, false_branch;
989 true_branch = COND_EXPR_THEN (stmt);
990 false_branch = COND_EXPR_ELSE (stmt);
992 GOTO_DESTINATION (true_branch)
993 = main_block_label (GOTO_DESTINATION (true_branch));
994 GOTO_DESTINATION (false_branch)
995 = main_block_label (GOTO_DESTINATION (false_branch));
1003 tree vec = SWITCH_LABELS (stmt);
1004 size_t n = TREE_VEC_LENGTH (vec);
1006 /* Replace all destination labels. */
1007 for (i = 0; i < n; ++i)
1009 tree elt = TREE_VEC_ELT (vec, i);
1010 tree label = main_block_label (CASE_LABEL (elt));
1011 CASE_LABEL (elt) = label;
1016 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1017 remove them until after we've created the CFG edges. */
1019 if (! computed_goto_p (stmt))
1021 GOTO_DESTINATION (stmt)
1022 = main_block_label (GOTO_DESTINATION (stmt));
1031 for_each_eh_region (update_eh_label);
1033 /* Finally, purge dead labels. All user-defined labels and labels that
1034 can be the target of non-local gotos and labels which have their
1035 address taken are preserved. */
1038 block_stmt_iterator i;
1039 tree label_for_this_bb = label_for_bb[bb->index];
1041 if (! label_for_this_bb)
1044 for (i = bsi_start (bb); !bsi_end_p (i); )
1046 tree label, stmt = bsi_stmt (i);
1048 if (TREE_CODE (stmt) != LABEL_EXPR)
1051 label = LABEL_EXPR_LABEL (stmt);
1053 if (label == label_for_this_bb
1054 || ! DECL_ARTIFICIAL (label)
1055 || DECL_NONLOCAL (label)
1056 || FORCED_LABEL (label))
1059 bsi_remove (&i, true);
1063 free (label_for_bb);
1066 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1067 and scan the sorted vector of cases. Combine the ones jumping to the
1069 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1072 group_case_labels (void)
1078 tree stmt = last_stmt (bb);
1079 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1081 tree labels = SWITCH_LABELS (stmt);
1082 int old_size = TREE_VEC_LENGTH (labels);
1083 int i, j, new_size = old_size;
1084 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1087 /* The default label is always the last case in a switch
1088 statement after gimplification. */
1089 default_label = CASE_LABEL (default_case);
1091 /* Look for possible opportunities to merge cases.
1092 Ignore the last element of the label vector because it
1093 must be the default case. */
1095 while (i < old_size - 1)
1097 tree base_case, base_label, base_high;
1098 base_case = TREE_VEC_ELT (labels, i);
1100 gcc_assert (base_case);
1101 base_label = CASE_LABEL (base_case);
1103 /* Discard cases that have the same destination as the
1105 if (base_label == default_label)
1107 TREE_VEC_ELT (labels, i) = NULL_TREE;
1113 base_high = CASE_HIGH (base_case) ?
1114 CASE_HIGH (base_case) : CASE_LOW (base_case);
1116 /* Try to merge case labels. Break out when we reach the end
1117 of the label vector or when we cannot merge the next case
1118 label with the current one. */
1119 while (i < old_size - 1)
1121 tree merge_case = TREE_VEC_ELT (labels, i);
1122 tree merge_label = CASE_LABEL (merge_case);
1123 tree t = int_const_binop (PLUS_EXPR, base_high,
1124 integer_one_node, 1);
1126 /* Merge the cases if they jump to the same place,
1127 and their ranges are consecutive. */
1128 if (merge_label == base_label
1129 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1131 base_high = CASE_HIGH (merge_case) ?
1132 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1133 CASE_HIGH (base_case) = base_high;
1134 TREE_VEC_ELT (labels, i) = NULL_TREE;
1143 /* Compress the case labels in the label vector, and adjust the
1144 length of the vector. */
1145 for (i = 0, j = 0; i < new_size; i++)
1147 while (! TREE_VEC_ELT (labels, j))
1149 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1151 TREE_VEC_LENGTH (labels) = new_size;
1156 /* Checks whether we can merge block B into block A. */
1159 tree_can_merge_blocks_p (basic_block a, basic_block b)
1162 block_stmt_iterator bsi;
1165 if (!single_succ_p (a))
1168 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1171 if (single_succ (a) != b)
1174 if (!single_pred_p (b))
1177 if (b == EXIT_BLOCK_PTR)
1180 /* If A ends by a statement causing exceptions or something similar, we
1181 cannot merge the blocks. */
1182 stmt = last_stmt (a);
1183 if (stmt && stmt_ends_bb_p (stmt))
1186 /* Do not allow a block with only a non-local label to be merged. */
1187 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1188 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1191 /* It must be possible to eliminate all phi nodes in B. If ssa form
1192 is not up-to-date, we cannot eliminate any phis; however, if only
1193 some symbols as whole are marked for renaming, this is not a problem,
1194 as phi nodes for those symbols are irrelevant in updating anyway. */
1195 phi = phi_nodes (b);
1198 if (name_mappings_registered_p ())
1201 for (; phi; phi = PHI_CHAIN (phi))
1202 if (!is_gimple_reg (PHI_RESULT (phi))
1203 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1207 /* Do not remove user labels. */
1208 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1210 stmt = bsi_stmt (bsi);
1211 if (TREE_CODE (stmt) != LABEL_EXPR)
1213 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1217 /* Protect the loop latches. */
1219 && b->loop_father->latch == b)
1225 /* Replaces all uses of NAME by VAL. */
1228 replace_uses_by (tree name, tree val)
1230 imm_use_iterator imm_iter;
1235 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1237 if (TREE_CODE (stmt) != PHI_NODE)
1238 push_stmt_changes (&stmt);
1240 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1242 replace_exp (use, val);
1244 if (TREE_CODE (stmt) == PHI_NODE)
1246 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1247 if (e->flags & EDGE_ABNORMAL)
1249 /* This can only occur for virtual operands, since
1250 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1251 would prevent replacement. */
1252 gcc_assert (!is_gimple_reg (name));
1253 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1258 if (TREE_CODE (stmt) != PHI_NODE)
1262 fold_stmt_inplace (stmt);
1264 /* FIXME. This should go in pop_stmt_changes. */
1265 rhs = get_rhs (stmt);
1266 if (TREE_CODE (rhs) == ADDR_EXPR)
1267 recompute_tree_invariant_for_addr_expr (rhs);
1269 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1271 pop_stmt_changes (&stmt);
1275 gcc_assert (zero_imm_uses_p (name));
1277 /* Also update the trees stored in loop structures. */
1283 FOR_EACH_LOOP (li, loop, 0)
1285 substitute_in_loop_info (loop, name, val);
1290 /* Merge block B into block A. */
1293 tree_merge_blocks (basic_block a, basic_block b)
1295 block_stmt_iterator bsi;
1296 tree_stmt_iterator last;
1300 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1302 /* Remove all single-valued PHI nodes from block B of the form
1303 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1305 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1307 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1309 bool may_replace_uses = may_propagate_copy (def, use);
1311 /* In case we have loops to care about, do not propagate arguments of
1312 loop closed ssa phi nodes. */
1314 && is_gimple_reg (def)
1315 && TREE_CODE (use) == SSA_NAME
1316 && a->loop_father != b->loop_father)
1317 may_replace_uses = false;
1319 if (!may_replace_uses)
1321 gcc_assert (is_gimple_reg (def));
1323 /* Note that just emitting the copies is fine -- there is no problem
1324 with ordering of phi nodes. This is because A is the single
1325 predecessor of B, therefore results of the phi nodes cannot
1326 appear as arguments of the phi nodes. */
1327 copy = build2_gimple (GIMPLE_MODIFY_STMT, def, use);
1328 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1329 SSA_NAME_DEF_STMT (def) = copy;
1330 remove_phi_node (phi, NULL, false);
1334 replace_uses_by (def, use);
1335 remove_phi_node (phi, NULL, true);
1339 /* Ensure that B follows A. */
1340 move_block_after (b, a);
1342 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1343 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1345 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1346 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1348 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1350 tree label = bsi_stmt (bsi);
1352 bsi_remove (&bsi, false);
1353 /* Now that we can thread computed gotos, we might have
1354 a situation where we have a forced label in block B
1355 However, the label at the start of block B might still be
1356 used in other ways (think about the runtime checking for
1357 Fortran assigned gotos). So we can not just delete the
1358 label. Instead we move the label to the start of block A. */
1359 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1361 block_stmt_iterator dest_bsi = bsi_start (a);
1362 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1367 change_bb_for_stmt (bsi_stmt (bsi), a);
1372 /* Merge the chains. */
1373 last = tsi_last (a->stmt_list);
1374 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1375 b->stmt_list = NULL;
1379 /* Return the one of two successors of BB that is not reachable by a
1380 reached by a complex edge, if there is one. Else, return BB. We use
1381 this in optimizations that use post-dominators for their heuristics,
1382 to catch the cases in C++ where function calls are involved. */
1385 single_noncomplex_succ (basic_block bb)
1388 if (EDGE_COUNT (bb->succs) != 2)
1391 e0 = EDGE_SUCC (bb, 0);
1392 e1 = EDGE_SUCC (bb, 1);
1393 if (e0->flags & EDGE_COMPLEX)
1395 if (e1->flags & EDGE_COMPLEX)
1402 /* Walk the function tree removing unnecessary statements.
1404 * Empty statement nodes are removed
1406 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1408 * Unnecessary COND_EXPRs are removed
1410 * Some unnecessary BIND_EXPRs are removed
1412 Clearly more work could be done. The trick is doing the analysis
1413 and removal fast enough to be a net improvement in compile times.
1415 Note that when we remove a control structure such as a COND_EXPR
1416 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1417 to ensure we eliminate all the useless code. */
1428 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1431 remove_useless_stmts_warn_notreached (tree stmt)
1433 if (EXPR_HAS_LOCATION (stmt))
1435 location_t loc = EXPR_LOCATION (stmt);
1436 if (LOCATION_LINE (loc) > 0)
1438 warning (0, "%Hwill never be executed", &loc);
1443 switch (TREE_CODE (stmt))
1445 case STATEMENT_LIST:
1447 tree_stmt_iterator i;
1448 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1449 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1455 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1457 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1459 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1463 case TRY_FINALLY_EXPR:
1464 case TRY_CATCH_EXPR:
1465 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1467 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1472 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1473 case EH_FILTER_EXPR:
1474 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1476 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1479 /* Not a live container. */
1487 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1489 tree then_clause, else_clause, cond;
1490 bool save_has_label, then_has_label, else_has_label;
1492 save_has_label = data->has_label;
1493 data->has_label = false;
1494 data->last_goto = NULL;
1496 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1498 then_has_label = data->has_label;
1499 data->has_label = false;
1500 data->last_goto = NULL;
1502 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1504 else_has_label = data->has_label;
1505 data->has_label = save_has_label | then_has_label | else_has_label;
1507 then_clause = COND_EXPR_THEN (*stmt_p);
1508 else_clause = COND_EXPR_ELSE (*stmt_p);
1509 cond = fold (COND_EXPR_COND (*stmt_p));
1511 /* If neither arm does anything at all, we can remove the whole IF. */
1512 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1514 *stmt_p = build_empty_stmt ();
1515 data->repeat = true;
1518 /* If there are no reachable statements in an arm, then we can
1519 zap the entire conditional. */
1520 else if (integer_nonzerop (cond) && !else_has_label)
1522 if (warn_notreached)
1523 remove_useless_stmts_warn_notreached (else_clause);
1524 *stmt_p = then_clause;
1525 data->repeat = true;
1527 else if (integer_zerop (cond) && !then_has_label)
1529 if (warn_notreached)
1530 remove_useless_stmts_warn_notreached (then_clause);
1531 *stmt_p = else_clause;
1532 data->repeat = true;
1535 /* Check a couple of simple things on then/else with single stmts. */
1538 tree then_stmt = expr_only (then_clause);
1539 tree else_stmt = expr_only (else_clause);
1541 /* Notice branches to a common destination. */
1542 if (then_stmt && else_stmt
1543 && TREE_CODE (then_stmt) == GOTO_EXPR
1544 && TREE_CODE (else_stmt) == GOTO_EXPR
1545 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1547 *stmt_p = then_stmt;
1548 data->repeat = true;
1551 /* If the THEN/ELSE clause merely assigns a value to a variable or
1552 parameter which is already known to contain that value, then
1553 remove the useless THEN/ELSE clause. */
1554 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1557 && TREE_CODE (else_stmt) == GIMPLE_MODIFY_STMT
1558 && GIMPLE_STMT_OPERAND (else_stmt, 0) == cond
1559 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt, 1)))
1560 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1562 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1563 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1564 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1565 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1567 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1568 ? then_stmt : else_stmt);
1569 tree *location = (TREE_CODE (cond) == EQ_EXPR
1570 ? &COND_EXPR_THEN (*stmt_p)
1571 : &COND_EXPR_ELSE (*stmt_p));
1574 && TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
1575 && GIMPLE_STMT_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1576 && GIMPLE_STMT_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1577 *location = alloc_stmt_list ();
1581 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1582 would be re-introduced during lowering. */
1583 data->last_goto = NULL;
1588 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1590 bool save_may_branch, save_may_throw;
1591 bool this_may_branch, this_may_throw;
1593 /* Collect may_branch and may_throw information for the body only. */
1594 save_may_branch = data->may_branch;
1595 save_may_throw = data->may_throw;
1596 data->may_branch = false;
1597 data->may_throw = false;
1598 data->last_goto = NULL;
1600 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1602 this_may_branch = data->may_branch;
1603 this_may_throw = data->may_throw;
1604 data->may_branch |= save_may_branch;
1605 data->may_throw |= save_may_throw;
1606 data->last_goto = NULL;
1608 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1610 /* If the body is empty, then we can emit the FINALLY block without
1611 the enclosing TRY_FINALLY_EXPR. */
1612 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1614 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1615 data->repeat = true;
1618 /* If the handler is empty, then we can emit the TRY block without
1619 the enclosing TRY_FINALLY_EXPR. */
1620 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1622 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1623 data->repeat = true;
1626 /* If the body neither throws, nor branches, then we can safely
1627 string the TRY and FINALLY blocks together. */
1628 else if (!this_may_branch && !this_may_throw)
1630 tree stmt = *stmt_p;
1631 *stmt_p = TREE_OPERAND (stmt, 0);
1632 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1633 data->repeat = true;
1639 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1641 bool save_may_throw, this_may_throw;
1642 tree_stmt_iterator i;
1645 /* Collect may_throw information for the body only. */
1646 save_may_throw = data->may_throw;
1647 data->may_throw = false;
1648 data->last_goto = NULL;
1650 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1652 this_may_throw = data->may_throw;
1653 data->may_throw = save_may_throw;
1655 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1656 if (!this_may_throw)
1658 if (warn_notreached)
1659 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1660 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1661 data->repeat = true;
1665 /* Process the catch clause specially. We may be able to tell that
1666 no exceptions propagate past this point. */
1668 this_may_throw = true;
1669 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1670 stmt = tsi_stmt (i);
1671 data->last_goto = NULL;
1673 switch (TREE_CODE (stmt))
1676 for (; !tsi_end_p (i); tsi_next (&i))
1678 stmt = tsi_stmt (i);
1679 /* If we catch all exceptions, then the body does not
1680 propagate exceptions past this point. */
1681 if (CATCH_TYPES (stmt) == NULL)
1682 this_may_throw = false;
1683 data->last_goto = NULL;
1684 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1688 case EH_FILTER_EXPR:
1689 if (EH_FILTER_MUST_NOT_THROW (stmt))
1690 this_may_throw = false;
1691 else if (EH_FILTER_TYPES (stmt) == NULL)
1692 this_may_throw = false;
1693 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1697 /* Otherwise this is a cleanup. */
1698 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1700 /* If the cleanup is empty, then we can emit the TRY block without
1701 the enclosing TRY_CATCH_EXPR. */
1702 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1704 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1705 data->repeat = true;
1709 data->may_throw |= this_may_throw;
1714 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1718 /* First remove anything underneath the BIND_EXPR. */
1719 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1721 /* If the BIND_EXPR has no variables, then we can pull everything
1722 up one level and remove the BIND_EXPR, unless this is the toplevel
1723 BIND_EXPR for the current function or an inlined function.
1725 When this situation occurs we will want to apply this
1726 optimization again. */
1727 block = BIND_EXPR_BLOCK (*stmt_p);
1728 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1729 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1731 || ! BLOCK_ABSTRACT_ORIGIN (block)
1732 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1735 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1736 data->repeat = true;
1742 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1744 tree dest = GOTO_DESTINATION (*stmt_p);
1746 data->may_branch = true;
1747 data->last_goto = NULL;
1749 /* Record the last goto expr, so that we can delete it if unnecessary. */
1750 if (TREE_CODE (dest) == LABEL_DECL)
1751 data->last_goto = stmt_p;
1756 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1758 tree label = LABEL_EXPR_LABEL (*stmt_p);
1760 data->has_label = true;
1762 /* We do want to jump across non-local label receiver code. */
1763 if (DECL_NONLOCAL (label))
1764 data->last_goto = NULL;
1766 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1768 *data->last_goto = build_empty_stmt ();
1769 data->repeat = true;
1772 /* ??? Add something here to delete unused labels. */
1776 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1777 decl. This allows us to eliminate redundant or useless
1778 calls to "const" functions.
1780 Gimplifier already does the same operation, but we may notice functions
1781 being const and pure once their calls has been gimplified, so we need
1782 to update the flag. */
1785 update_call_expr_flags (tree call)
1787 tree decl = get_callee_fndecl (call);
1790 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1791 TREE_SIDE_EFFECTS (call) = 0;
1792 if (TREE_NOTHROW (decl))
1793 TREE_NOTHROW (call) = 1;
1797 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1800 notice_special_calls (tree t)
1802 int flags = call_expr_flags (t);
1804 if (flags & ECF_MAY_BE_ALLOCA)
1805 current_function_calls_alloca = true;
1806 if (flags & ECF_RETURNS_TWICE)
1807 current_function_calls_setjmp = true;
1811 /* Clear flags set by notice_special_calls. Used by dead code removal
1812 to update the flags. */
1815 clear_special_calls (void)
1817 current_function_calls_alloca = false;
1818 current_function_calls_setjmp = false;
1823 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1827 switch (TREE_CODE (t))
1830 remove_useless_stmts_cond (tp, data);
1833 case TRY_FINALLY_EXPR:
1834 remove_useless_stmts_tf (tp, data);
1837 case TRY_CATCH_EXPR:
1838 remove_useless_stmts_tc (tp, data);
1842 remove_useless_stmts_bind (tp, data);
1846 remove_useless_stmts_goto (tp, data);
1850 remove_useless_stmts_label (tp, data);
1855 data->last_goto = NULL;
1856 data->may_branch = true;
1861 data->last_goto = NULL;
1862 notice_special_calls (t);
1863 update_call_expr_flags (t);
1864 if (tree_could_throw_p (t))
1865 data->may_throw = true;
1871 case GIMPLE_MODIFY_STMT:
1872 data->last_goto = NULL;
1874 op = get_call_expr_in (t);
1877 update_call_expr_flags (op);
1878 notice_special_calls (op);
1880 if (tree_could_throw_p (t))
1881 data->may_throw = true;
1884 case STATEMENT_LIST:
1886 tree_stmt_iterator i = tsi_start (t);
1887 while (!tsi_end_p (i))
1890 if (IS_EMPTY_STMT (t))
1896 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1899 if (TREE_CODE (t) == STATEMENT_LIST)
1901 tsi_link_before (&i, t, TSI_SAME_STMT);
1911 data->last_goto = NULL;
1915 data->last_goto = NULL;
1921 remove_useless_stmts (void)
1923 struct rus_data data;
1925 clear_special_calls ();
1929 memset (&data, 0, sizeof (data));
1930 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1932 while (data.repeat);
1937 struct tree_opt_pass pass_remove_useless_stmts =
1939 "useless", /* name */
1941 remove_useless_stmts, /* execute */
1944 0, /* static_pass_number */
1946 PROP_gimple_any, /* properties_required */
1947 0, /* properties_provided */
1948 0, /* properties_destroyed */
1949 0, /* todo_flags_start */
1950 TODO_dump_func, /* todo_flags_finish */
1954 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1957 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1961 /* Since this block is no longer reachable, we can just delete all
1962 of its PHI nodes. */
1963 phi = phi_nodes (bb);
1966 tree next = PHI_CHAIN (phi);
1967 remove_phi_node (phi, NULL_TREE, true);
1971 /* Remove edges to BB's successors. */
1972 while (EDGE_COUNT (bb->succs) > 0)
1973 remove_edge (EDGE_SUCC (bb, 0));
1977 /* Remove statements of basic block BB. */
1980 remove_bb (basic_block bb)
1982 block_stmt_iterator i;
1983 #ifdef USE_MAPPED_LOCATION
1984 source_location loc = UNKNOWN_LOCATION;
1986 source_locus loc = 0;
1991 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1992 if (dump_flags & TDF_DETAILS)
1994 dump_bb (bb, dump_file, 0);
1995 fprintf (dump_file, "\n");
2001 struct loop *loop = bb->loop_father;
2003 /* If a loop gets removed, clean up the information associated
2005 if (loop->latch == bb
2006 || loop->header == bb)
2007 free_numbers_of_iterations_estimates_loop (loop);
2010 /* Remove all the instructions in the block. */
2011 for (i = bsi_start (bb); !bsi_end_p (i);)
2013 tree stmt = bsi_stmt (i);
2014 if (TREE_CODE (stmt) == LABEL_EXPR
2015 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2016 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2019 block_stmt_iterator new_bsi;
2021 /* A non-reachable non-local label may still be referenced.
2022 But it no longer needs to carry the extra semantics of
2024 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2026 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2027 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2030 new_bb = bb->prev_bb;
2031 new_bsi = bsi_start (new_bb);
2032 bsi_remove (&i, false);
2033 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2037 /* Release SSA definitions if we are in SSA. Note that we
2038 may be called when not in SSA. For example,
2039 final_cleanup calls this function via
2040 cleanup_tree_cfg. */
2041 if (gimple_in_ssa_p (cfun))
2042 release_defs (stmt);
2044 bsi_remove (&i, true);
2047 /* Don't warn for removed gotos. Gotos are often removed due to
2048 jump threading, thus resulting in bogus warnings. Not great,
2049 since this way we lose warnings for gotos in the original
2050 program that are indeed unreachable. */
2051 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2053 #ifdef USE_MAPPED_LOCATION
2054 if (EXPR_HAS_LOCATION (stmt))
2055 loc = EXPR_LOCATION (stmt);
2058 t = EXPR_LOCUS (stmt);
2059 if (t && LOCATION_LINE (*t) > 0)
2065 /* If requested, give a warning that the first statement in the
2066 block is unreachable. We walk statements backwards in the
2067 loop above, so the last statement we process is the first statement
2069 #ifdef USE_MAPPED_LOCATION
2070 if (loc > BUILTINS_LOCATION)
2071 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2074 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2077 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2081 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2082 predicate VAL, return the edge that will be taken out of the block.
2083 If VAL does not match a unique edge, NULL is returned. */
2086 find_taken_edge (basic_block bb, tree val)
2090 stmt = last_stmt (bb);
2093 gcc_assert (is_ctrl_stmt (stmt));
2096 if (! is_gimple_min_invariant (val))
2099 if (TREE_CODE (stmt) == COND_EXPR)
2100 return find_taken_edge_cond_expr (bb, val);
2102 if (TREE_CODE (stmt) == SWITCH_EXPR)
2103 return find_taken_edge_switch_expr (bb, val);
2105 if (computed_goto_p (stmt))
2106 return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
2111 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2112 statement, determine which of the outgoing edges will be taken out of the
2113 block. Return NULL if either edge may be taken. */
2116 find_taken_edge_computed_goto (basic_block bb, tree val)
2121 dest = label_to_block (val);
2124 e = find_edge (bb, dest);
2125 gcc_assert (e != NULL);
2131 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2132 statement, determine which of the two edges will be taken out of the
2133 block. Return NULL if either edge may be taken. */
2136 find_taken_edge_cond_expr (basic_block bb, tree val)
2138 edge true_edge, false_edge;
2140 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2142 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2143 return (integer_zerop (val) ? false_edge : true_edge);
2146 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2147 statement, determine which edge will be taken out of the block. Return
2148 NULL if any edge may be taken. */
2151 find_taken_edge_switch_expr (basic_block bb, tree val)
2153 tree switch_expr, taken_case;
2154 basic_block dest_bb;
2157 switch_expr = last_stmt (bb);
2158 taken_case = find_case_label_for_value (switch_expr, val);
2159 dest_bb = label_to_block (CASE_LABEL (taken_case));
2161 e = find_edge (bb, dest_bb);
2167 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2168 We can make optimal use here of the fact that the case labels are
2169 sorted: We can do a binary search for a case matching VAL. */
2172 find_case_label_for_value (tree switch_expr, tree val)
2174 tree vec = SWITCH_LABELS (switch_expr);
2175 size_t low, high, n = TREE_VEC_LENGTH (vec);
2176 tree default_case = TREE_VEC_ELT (vec, n - 1);
2178 for (low = -1, high = n - 1; high - low > 1; )
2180 size_t i = (high + low) / 2;
2181 tree t = TREE_VEC_ELT (vec, i);
2184 /* Cache the result of comparing CASE_LOW and val. */
2185 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2192 if (CASE_HIGH (t) == NULL)
2194 /* A singe-valued case label. */
2200 /* A case range. We can only handle integer ranges. */
2201 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2206 return default_case;
2212 /*---------------------------------------------------------------------------
2214 ---------------------------------------------------------------------------*/
2216 /* Dump tree-specific information of block BB to file OUTF. */
2219 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2221 dump_generic_bb (outf, bb, indent, TDF_VOPS|TDF_MEMSYMS);
2225 /* Dump a basic block on stderr. */
2228 debug_tree_bb (basic_block bb)
2230 dump_bb (bb, stderr, 0);
2234 /* Dump basic block with index N on stderr. */
2237 debug_tree_bb_n (int n)
2239 debug_tree_bb (BASIC_BLOCK (n));
2240 return BASIC_BLOCK (n);
2244 /* Dump the CFG on stderr.
2246 FLAGS are the same used by the tree dumping functions
2247 (see TDF_* in tree-pass.h). */
2250 debug_tree_cfg (int flags)
2252 dump_tree_cfg (stderr, flags);
2256 /* Dump the program showing basic block boundaries on the given FILE.
2258 FLAGS are the same used by the tree dumping functions (see TDF_* in
2262 dump_tree_cfg (FILE *file, int flags)
2264 if (flags & TDF_DETAILS)
2266 const char *funcname
2267 = lang_hooks.decl_printable_name (current_function_decl, 2);
2270 fprintf (file, ";; Function %s\n\n", funcname);
2271 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2272 n_basic_blocks, n_edges, last_basic_block);
2274 brief_dump_cfg (file);
2275 fprintf (file, "\n");
2278 if (flags & TDF_STATS)
2279 dump_cfg_stats (file);
2281 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2285 /* Dump CFG statistics on FILE. */
2288 dump_cfg_stats (FILE *file)
2290 static long max_num_merged_labels = 0;
2291 unsigned long size, total = 0;
2294 const char * const fmt_str = "%-30s%-13s%12s\n";
2295 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2296 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2297 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2298 const char *funcname
2299 = lang_hooks.decl_printable_name (current_function_decl, 2);
2302 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2304 fprintf (file, "---------------------------------------------------------\n");
2305 fprintf (file, fmt_str, "", " Number of ", "Memory");
2306 fprintf (file, fmt_str, "", " instances ", "used ");
2307 fprintf (file, "---------------------------------------------------------\n");
2309 size = n_basic_blocks * sizeof (struct basic_block_def);
2311 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2312 SCALE (size), LABEL (size));
2316 num_edges += EDGE_COUNT (bb->succs);
2317 size = num_edges * sizeof (struct edge_def);
2319 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2321 fprintf (file, "---------------------------------------------------------\n");
2322 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2324 fprintf (file, "---------------------------------------------------------\n");
2325 fprintf (file, "\n");
2327 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2328 max_num_merged_labels = cfg_stats.num_merged_labels;
2330 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2331 cfg_stats.num_merged_labels, max_num_merged_labels);
2333 fprintf (file, "\n");
2337 /* Dump CFG statistics on stderr. Keep extern so that it's always
2338 linked in the final executable. */
2341 debug_cfg_stats (void)
2343 dump_cfg_stats (stderr);
2347 /* Dump the flowgraph to a .vcg FILE. */
2350 tree_cfg2vcg (FILE *file)
2355 const char *funcname
2356 = lang_hooks.decl_printable_name (current_function_decl, 2);
2358 /* Write the file header. */
2359 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2360 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2361 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2363 /* Write blocks and edges. */
2364 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2366 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2369 if (e->flags & EDGE_FAKE)
2370 fprintf (file, " linestyle: dotted priority: 10");
2372 fprintf (file, " linestyle: solid priority: 100");
2374 fprintf (file, " }\n");
2380 enum tree_code head_code, end_code;
2381 const char *head_name, *end_name;
2384 tree first = first_stmt (bb);
2385 tree last = last_stmt (bb);
2389 head_code = TREE_CODE (first);
2390 head_name = tree_code_name[head_code];
2391 head_line = get_lineno (first);
2394 head_name = "no-statement";
2398 end_code = TREE_CODE (last);
2399 end_name = tree_code_name[end_code];
2400 end_line = get_lineno (last);
2403 end_name = "no-statement";
2405 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2406 bb->index, bb->index, head_name, head_line, end_name,
2409 FOR_EACH_EDGE (e, ei, bb->succs)
2411 if (e->dest == EXIT_BLOCK_PTR)
2412 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2414 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2416 if (e->flags & EDGE_FAKE)
2417 fprintf (file, " priority: 10 linestyle: dotted");
2419 fprintf (file, " priority: 100 linestyle: solid");
2421 fprintf (file, " }\n");
2424 if (bb->next_bb != EXIT_BLOCK_PTR)
2428 fputs ("}\n\n", file);
2433 /*---------------------------------------------------------------------------
2434 Miscellaneous helpers
2435 ---------------------------------------------------------------------------*/
2437 /* Return true if T represents a stmt that always transfers control. */
2440 is_ctrl_stmt (tree t)
2442 return (TREE_CODE (t) == COND_EXPR
2443 || TREE_CODE (t) == SWITCH_EXPR
2444 || TREE_CODE (t) == GOTO_EXPR
2445 || TREE_CODE (t) == RETURN_EXPR
2446 || TREE_CODE (t) == RESX_EXPR);
2450 /* Return true if T is a statement that may alter the flow of control
2451 (e.g., a call to a non-returning function). */
2454 is_ctrl_altering_stmt (tree t)
2459 call = get_call_expr_in (t);
2462 /* A non-pure/const CALL_EXPR alters flow control if the current
2463 function has nonlocal labels. */
2464 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2467 /* A CALL_EXPR also alters control flow if it does not return. */
2468 if (call_expr_flags (call) & ECF_NORETURN)
2472 /* OpenMP directives alter control flow. */
2473 if (OMP_DIRECTIVE_P (t))
2476 /* If a statement can throw, it alters control flow. */
2477 return tree_can_throw_internal (t);
2481 /* Return true if T is a computed goto. */
2484 computed_goto_p (tree t)
2486 return (TREE_CODE (t) == GOTO_EXPR
2487 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2491 /* Return true if T is a simple local goto. */
2494 simple_goto_p (tree t)
2496 return (TREE_CODE (t) == GOTO_EXPR
2497 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2501 /* Return true if T can make an abnormal transfer of control flow.
2502 Transfers of control flow associated with EH are excluded. */
2505 tree_can_make_abnormal_goto (tree t)
2507 if (computed_goto_p (t))
2509 if (TREE_CODE (t) == GIMPLE_MODIFY_STMT)
2510 t = GIMPLE_STMT_OPERAND (t, 1);
2511 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2512 t = TREE_OPERAND (t, 0);
2513 if (TREE_CODE (t) == CALL_EXPR)
2514 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2519 /* Return true if T should start a new basic block. PREV_T is the
2520 statement preceding T. It is used when T is a label or a case label.
2521 Labels should only start a new basic block if their previous statement
2522 wasn't a label. Otherwise, sequence of labels would generate
2523 unnecessary basic blocks that only contain a single label. */
2526 stmt_starts_bb_p (tree t, tree prev_t)
2531 /* LABEL_EXPRs start a new basic block only if the preceding
2532 statement wasn't a label of the same type. This prevents the
2533 creation of consecutive blocks that have nothing but a single
2535 if (TREE_CODE (t) == LABEL_EXPR)
2537 /* Nonlocal and computed GOTO targets always start a new block. */
2538 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2539 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2542 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2544 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2547 cfg_stats.num_merged_labels++;
2558 /* Return true if T should end a basic block. */
2561 stmt_ends_bb_p (tree t)
2563 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2567 /* Add gotos that used to be represented implicitly in the CFG. */
2570 disband_implicit_edges (void)
2573 block_stmt_iterator last;
2580 last = bsi_last (bb);
2581 stmt = last_stmt (bb);
2583 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2585 /* Remove superfluous gotos from COND_EXPR branches. Moved
2586 from cfg_remove_useless_stmts here since it violates the
2587 invariants for tree--cfg correspondence and thus fits better
2588 here where we do it anyway. */
2589 e = find_edge (bb, bb->next_bb);
2592 if (e->flags & EDGE_TRUE_VALUE)
2593 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2594 else if (e->flags & EDGE_FALSE_VALUE)
2595 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2598 e->flags |= EDGE_FALLTHRU;
2604 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2606 /* Remove the RETURN_EXPR if we may fall though to the exit
2608 gcc_assert (single_succ_p (bb));
2609 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2611 if (bb->next_bb == EXIT_BLOCK_PTR
2612 && !TREE_OPERAND (stmt, 0))
2614 bsi_remove (&last, true);
2615 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2620 /* There can be no fallthru edge if the last statement is a control
2622 if (stmt && is_ctrl_stmt (stmt))
2625 /* Find a fallthru edge and emit the goto if necessary. */
2626 FOR_EACH_EDGE (e, ei, bb->succs)
2627 if (e->flags & EDGE_FALLTHRU)
2630 if (!e || e->dest == bb->next_bb)
2633 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2634 label = tree_block_label (e->dest);
2636 stmt = build1 (GOTO_EXPR, void_type_node, label);
2637 #ifdef USE_MAPPED_LOCATION
2638 SET_EXPR_LOCATION (stmt, e->goto_locus);
2640 SET_EXPR_LOCUS (stmt, e->goto_locus);
2642 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2643 e->flags &= ~EDGE_FALLTHRU;
2647 /* Remove block annotations and other datastructures. */
2650 delete_tree_cfg_annotations (void)
2653 block_stmt_iterator bsi;
2655 /* Remove annotations from every tree in the function. */
2657 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
2659 tree stmt = bsi_stmt (bsi);
2660 ggc_free (stmt->base.ann);
2661 stmt->base.ann = NULL;
2663 label_to_block_map = NULL;
2667 /* Return the first statement in basic block BB. */
2670 first_stmt (basic_block bb)
2672 block_stmt_iterator i = bsi_start (bb);
2673 return !bsi_end_p (i) ? bsi_stmt (i) : NULL_TREE;
2677 /* Return the last statement in basic block BB. */
2680 last_stmt (basic_block bb)
2682 block_stmt_iterator b = bsi_last (bb);
2683 return !bsi_end_p (b) ? bsi_stmt (b) : NULL_TREE;
2687 /* Return the last statement of an otherwise empty block. Return NULL
2688 if the block is totally empty, or if it contains more than one
2692 last_and_only_stmt (basic_block bb)
2694 block_stmt_iterator i = bsi_last (bb);
2700 last = bsi_stmt (i);
2705 /* Empty statements should no longer appear in the instruction stream.
2706 Everything that might have appeared before should be deleted by
2707 remove_useless_stmts, and the optimizers should just bsi_remove
2708 instead of smashing with build_empty_stmt.
2710 Thus the only thing that should appear here in a block containing
2711 one executable statement is a label. */
2712 prev = bsi_stmt (i);
2713 if (TREE_CODE (prev) == LABEL_EXPR)
2720 /* Mark BB as the basic block holding statement T. */
2723 set_bb_for_stmt (tree t, basic_block bb)
2725 if (TREE_CODE (t) == PHI_NODE)
2727 else if (TREE_CODE (t) == STATEMENT_LIST)
2729 tree_stmt_iterator i;
2730 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2731 set_bb_for_stmt (tsi_stmt (i), bb);
2735 stmt_ann_t ann = get_stmt_ann (t);
2738 /* If the statement is a label, add the label to block-to-labels map
2739 so that we can speed up edge creation for GOTO_EXPRs. */
2740 if (TREE_CODE (t) == LABEL_EXPR)
2744 t = LABEL_EXPR_LABEL (t);
2745 uid = LABEL_DECL_UID (t);
2748 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2749 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2750 if (old_len <= (unsigned) uid)
2752 unsigned new_len = 3 * uid / 2;
2754 VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
2759 /* We're moving an existing label. Make sure that we've
2760 removed it from the old block. */
2762 || !VEC_index (basic_block, label_to_block_map, uid));
2763 VEC_replace (basic_block, label_to_block_map, uid, bb);
2768 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2769 from one basic block to another.
2770 For BB splitting we can run into quadratic case, so performance is quite
2771 important and knowing that the tables are big enough, change_bb_for_stmt
2772 can inline as leaf function. */
2774 change_bb_for_stmt (tree t, basic_block bb)
2776 get_stmt_ann (t)->bb = bb;
2777 if (TREE_CODE (t) == LABEL_EXPR)
2778 VEC_replace (basic_block, label_to_block_map,
2779 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2782 /* Finds iterator for STMT. */
2784 extern block_stmt_iterator
2785 bsi_for_stmt (tree stmt)
2787 block_stmt_iterator bsi;
2789 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2790 if (bsi_stmt (bsi) == stmt)
2796 /* Mark statement T as modified, and update it. */
2798 update_modified_stmts (tree t)
2800 if (!ssa_operands_active ())
2802 if (TREE_CODE (t) == STATEMENT_LIST)
2804 tree_stmt_iterator i;
2806 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2808 stmt = tsi_stmt (i);
2809 update_stmt_if_modified (stmt);
2813 update_stmt_if_modified (t);
2816 /* Insert statement (or statement list) T before the statement
2817 pointed-to by iterator I. M specifies how to update iterator I
2818 after insertion (see enum bsi_iterator_update). */
2821 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2823 set_bb_for_stmt (t, i->bb);
2824 update_modified_stmts (t);
2825 tsi_link_before (&i->tsi, t, m);
2829 /* Insert statement (or statement list) T after the statement
2830 pointed-to by iterator I. M specifies how to update iterator I
2831 after insertion (see enum bsi_iterator_update). */
2834 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2836 set_bb_for_stmt (t, i->bb);
2837 update_modified_stmts (t);
2838 tsi_link_after (&i->tsi, t, m);
2842 /* Remove the statement pointed to by iterator I. The iterator is updated
2843 to the next statement.
2845 When REMOVE_EH_INFO is true we remove the statement pointed to by
2846 iterator I from the EH tables. Otherwise we do not modify the EH
2849 Generally, REMOVE_EH_INFO should be true when the statement is going to
2850 be removed from the IL and not reinserted elsewhere. */
2853 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2855 tree t = bsi_stmt (*i);
2856 set_bb_for_stmt (t, NULL);
2857 delink_stmt_imm_use (t);
2858 tsi_delink (&i->tsi);
2859 mark_stmt_modified (t);
2862 remove_stmt_from_eh_region (t);
2863 gimple_remove_stmt_histograms (cfun, t);
2868 /* Move the statement at FROM so it comes right after the statement at TO. */
2871 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2873 tree stmt = bsi_stmt (*from);
2874 bsi_remove (from, false);
2875 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2879 /* Move the statement at FROM so it comes right before the statement at TO. */
2882 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2884 tree stmt = bsi_stmt (*from);
2885 bsi_remove (from, false);
2886 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2890 /* Move the statement at FROM to the end of basic block BB. */
2893 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2895 block_stmt_iterator last = bsi_last (bb);
2897 /* Have to check bsi_end_p because it could be an empty block. */
2898 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2899 bsi_move_before (from, &last);
2901 bsi_move_after (from, &last);
2905 /* Replace the contents of the statement pointed to by iterator BSI
2906 with STMT. If UPDATE_EH_INFO is true, the exception handling
2907 information of the original statement is moved to the new statement. */
2910 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2913 tree orig_stmt = bsi_stmt (*bsi);
2915 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2916 set_bb_for_stmt (stmt, bsi->bb);
2918 /* Preserve EH region information from the original statement, if
2919 requested by the caller. */
2922 eh_region = lookup_stmt_eh_region (orig_stmt);
2925 remove_stmt_from_eh_region (orig_stmt);
2926 add_stmt_to_eh_region (stmt, eh_region);
2927 gimple_duplicate_stmt_histograms (cfun, stmt, cfun, orig_stmt);
2928 gimple_remove_stmt_histograms (cfun, orig_stmt);
2932 delink_stmt_imm_use (orig_stmt);
2933 *bsi_stmt_ptr (*bsi) = stmt;
2934 mark_stmt_modified (stmt);
2935 update_modified_stmts (stmt);
2939 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2940 is made to place the statement in an existing basic block, but
2941 sometimes that isn't possible. When it isn't possible, the edge is
2942 split and the statement is added to the new block.
2944 In all cases, the returned *BSI points to the correct location. The
2945 return value is true if insertion should be done after the location,
2946 or false if it should be done before the location. If new basic block
2947 has to be created, it is stored in *NEW_BB. */
2950 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2951 basic_block *new_bb)
2953 basic_block dest, src;
2959 /* If the destination has one predecessor which has no PHI nodes,
2960 insert there. Except for the exit block.
2962 The requirement for no PHI nodes could be relaxed. Basically we
2963 would have to examine the PHIs to prove that none of them used
2964 the value set by the statement we want to insert on E. That
2965 hardly seems worth the effort. */
2966 if (single_pred_p (dest)
2967 && ! phi_nodes (dest)
2968 && dest != EXIT_BLOCK_PTR)
2970 *bsi = bsi_start (dest);
2971 if (bsi_end_p (*bsi))
2974 /* Make sure we insert after any leading labels. */
2975 tmp = bsi_stmt (*bsi);
2976 while (TREE_CODE (tmp) == LABEL_EXPR)
2979 if (bsi_end_p (*bsi))
2981 tmp = bsi_stmt (*bsi);
2984 if (bsi_end_p (*bsi))
2986 *bsi = bsi_last (dest);
2993 /* If the source has one successor, the edge is not abnormal and
2994 the last statement does not end a basic block, insert there.
2995 Except for the entry block. */
2997 if ((e->flags & EDGE_ABNORMAL) == 0
2998 && single_succ_p (src)
2999 && src != ENTRY_BLOCK_PTR)
3001 *bsi = bsi_last (src);
3002 if (bsi_end_p (*bsi))
3005 tmp = bsi_stmt (*bsi);
3006 if (!stmt_ends_bb_p (tmp))
3009 /* Insert code just before returning the value. We may need to decompose
3010 the return in the case it contains non-trivial operand. */
3011 if (TREE_CODE (tmp) == RETURN_EXPR)
3013 tree op = TREE_OPERAND (tmp, 0);
3014 if (op && !is_gimple_val (op))
3016 gcc_assert (TREE_CODE (op) == GIMPLE_MODIFY_STMT);
3017 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3018 TREE_OPERAND (tmp, 0) = GIMPLE_STMT_OPERAND (op, 0);
3025 /* Otherwise, create a new basic block, and split this edge. */
3026 dest = split_edge (e);
3029 e = single_pred_edge (dest);
3034 /* This routine will commit all pending edge insertions, creating any new
3035 basic blocks which are necessary. */
3038 bsi_commit_edge_inserts (void)
3044 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3047 FOR_EACH_EDGE (e, ei, bb->succs)
3048 bsi_commit_one_edge_insert (e, NULL);
3052 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3053 to this block, otherwise set it to NULL. */
3056 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3060 if (PENDING_STMT (e))
3062 block_stmt_iterator bsi;
3063 tree stmt = PENDING_STMT (e);
3065 PENDING_STMT (e) = NULL_TREE;
3067 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3068 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3070 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3075 /* Add STMT to the pending list of edge E. No actual insertion is
3076 made until a call to bsi_commit_edge_inserts () is made. */
3079 bsi_insert_on_edge (edge e, tree stmt)
3081 append_to_statement_list (stmt, &PENDING_STMT (e));
3084 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3085 block has to be created, it is returned. */
3088 bsi_insert_on_edge_immediate (edge e, tree stmt)
3090 block_stmt_iterator bsi;
3091 basic_block new_bb = NULL;
3093 gcc_assert (!PENDING_STMT (e));
3095 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3096 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3098 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3103 /*---------------------------------------------------------------------------
3104 Tree specific functions for CFG manipulation
3105 ---------------------------------------------------------------------------*/
3107 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3110 reinstall_phi_args (edge new_edge, edge old_edge)
3114 if (!PENDING_STMT (old_edge))
3117 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3119 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3121 tree result = TREE_PURPOSE (var);
3122 tree arg = TREE_VALUE (var);
3124 gcc_assert (result == PHI_RESULT (phi));
3126 add_phi_arg (phi, arg, new_edge);
3129 PENDING_STMT (old_edge) = NULL;
3132 /* Returns the basic block after which the new basic block created
3133 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3134 near its "logical" location. This is of most help to humans looking
3135 at debugging dumps. */
3138 split_edge_bb_loc (edge edge_in)
3140 basic_block dest = edge_in->dest;
3142 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3143 return edge_in->src;
3145 return dest->prev_bb;
3148 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3149 Abort on abnormal edges. */
3152 tree_split_edge (edge edge_in)
3154 basic_block new_bb, after_bb, dest;
3157 /* Abnormal edges cannot be split. */
3158 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3160 dest = edge_in->dest;
3162 after_bb = split_edge_bb_loc (edge_in);
3164 new_bb = create_empty_bb (after_bb);
3165 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3166 new_bb->count = edge_in->count;
3167 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3168 new_edge->probability = REG_BR_PROB_BASE;
3169 new_edge->count = edge_in->count;
3171 e = redirect_edge_and_branch (edge_in, new_bb);
3173 reinstall_phi_args (new_edge, e);
3179 /* Return true when BB has label LABEL in it. */
3182 has_label_p (basic_block bb, tree label)
3184 block_stmt_iterator bsi;
3186 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3188 tree stmt = bsi_stmt (bsi);
3190 if (TREE_CODE (stmt) != LABEL_EXPR)
3192 if (LABEL_EXPR_LABEL (stmt) == label)
3199 /* Callback for walk_tree, check that all elements with address taken are
3200 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3201 inside a PHI node. */
3204 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3207 bool in_phi = (data != NULL);
3212 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3213 #define CHECK_OP(N, MSG) \
3214 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3215 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3217 switch (TREE_CODE (t))
3220 if (SSA_NAME_IN_FREE_LIST (t))
3222 error ("SSA name in freelist but still referenced");
3228 x = fold (ASSERT_EXPR_COND (t));
3229 if (x == boolean_false_node)
3231 error ("ASSERT_EXPR with an always-false condition");
3239 case GIMPLE_MODIFY_STMT:
3240 x = GIMPLE_STMT_OPERAND (t, 0);
3241 if (TREE_CODE (x) == BIT_FIELD_REF
3242 && is_gimple_reg (TREE_OPERAND (x, 0)))
3244 error ("GIMPLE register modified with BIT_FIELD_REF");
3253 bool old_side_effects;
3256 bool new_side_effects;
3258 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3259 dead PHIs that take the address of something. But if the PHI
3260 result is dead, the fact that it takes the address of anything
3261 is irrelevant. Because we can not tell from here if a PHI result
3262 is dead, we just skip this check for PHIs altogether. This means
3263 we may be missing "valid" checks, but what can you do?
3264 This was PR19217. */
3268 old_invariant = TREE_INVARIANT (t);
3269 old_constant = TREE_CONSTANT (t);
3270 old_side_effects = TREE_SIDE_EFFECTS (t);
3272 recompute_tree_invariant_for_addr_expr (t);
3273 new_invariant = TREE_INVARIANT (t);
3274 new_side_effects = TREE_SIDE_EFFECTS (t);
3275 new_constant = TREE_CONSTANT (t);
3277 if (old_invariant != new_invariant)
3279 error ("invariant not recomputed when ADDR_EXPR changed");
3283 if (old_constant != new_constant)
3285 error ("constant not recomputed when ADDR_EXPR changed");
3288 if (old_side_effects != new_side_effects)
3290 error ("side effects not recomputed when ADDR_EXPR changed");
3294 /* Skip any references (they will be checked when we recurse down the
3295 tree) and ensure that any variable used as a prefix is marked
3297 for (x = TREE_OPERAND (t, 0);
3298 handled_component_p (x);
3299 x = TREE_OPERAND (x, 0))
3302 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3304 if (!TREE_ADDRESSABLE (x))
3306 error ("address taken, but ADDRESSABLE bit not set");
3313 x = COND_EXPR_COND (t);
3314 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3316 error ("non-boolean used in condition");
3319 if (!is_gimple_condexpr (x))
3321 error ("invalid conditional operand");
3328 case FIX_TRUNC_EXPR:
3333 case NON_LVALUE_EXPR:
3334 case TRUTH_NOT_EXPR:
3335 CHECK_OP (0, "invalid operand to unary operator");
3342 case ARRAY_RANGE_REF:
3344 case VIEW_CONVERT_EXPR:
3345 /* We have a nest of references. Verify that each of the operands
3346 that determine where to reference is either a constant or a variable,
3347 verify that the base is valid, and then show we've already checked
3349 while (handled_component_p (t))
3351 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3352 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3353 else if (TREE_CODE (t) == ARRAY_REF
3354 || TREE_CODE (t) == ARRAY_RANGE_REF)
3356 CHECK_OP (1, "invalid array index");
3357 if (TREE_OPERAND (t, 2))
3358 CHECK_OP (2, "invalid array lower bound");
3359 if (TREE_OPERAND (t, 3))
3360 CHECK_OP (3, "invalid array stride");
3362 else if (TREE_CODE (t) == BIT_FIELD_REF)
3364 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3365 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3368 t = TREE_OPERAND (t, 0);
3371 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3373 error ("invalid reference prefix");
3385 case UNORDERED_EXPR:
3396 case TRUNC_DIV_EXPR:
3398 case FLOOR_DIV_EXPR:
3399 case ROUND_DIV_EXPR:
3400 case TRUNC_MOD_EXPR:
3402 case FLOOR_MOD_EXPR:
3403 case ROUND_MOD_EXPR:
3405 case EXACT_DIV_EXPR:
3415 CHECK_OP (0, "invalid operand to binary operator");
3416 CHECK_OP (1, "invalid operand to binary operator");
3420 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3433 /* Verify STMT, return true if STMT is not in GIMPLE form.
3434 TODO: Implement type checking. */
3437 verify_stmt (tree stmt, bool last_in_block)
3441 if (OMP_DIRECTIVE_P (stmt))
3443 /* OpenMP directives are validated by the FE and never operated
3444 on by the optimizers. Furthermore, OMP_FOR may contain
3445 non-gimple expressions when the main index variable has had
3446 its address taken. This does not affect the loop itself
3447 because the header of an OMP_FOR is merely used to determine
3448 how to setup the parallel iteration. */
3452 if (!is_gimple_stmt (stmt))
3454 error ("is not a valid GIMPLE statement");
3458 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3461 debug_generic_stmt (addr);
3465 /* If the statement is marked as part of an EH region, then it is
3466 expected that the statement could throw. Verify that when we
3467 have optimizations that simplify statements such that we prove
3468 that they cannot throw, that we update other data structures
3470 if (lookup_stmt_eh_region (stmt) >= 0)
3472 if (!tree_could_throw_p (stmt))
3474 error ("statement marked for throw, but doesn%'t");
3477 if (!last_in_block && tree_can_throw_internal (stmt))
3479 error ("statement marked for throw in middle of block");
3487 debug_generic_stmt (stmt);
3492 /* Return true when the T can be shared. */
3495 tree_node_can_be_shared (tree t)
3497 if (IS_TYPE_OR_DECL_P (t)
3498 || is_gimple_min_invariant (t)
3499 || TREE_CODE (t) == SSA_NAME
3500 || t == error_mark_node
3501 || TREE_CODE (t) == IDENTIFIER_NODE)
3504 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3507 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3508 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3509 || TREE_CODE (t) == COMPONENT_REF
3510 || TREE_CODE (t) == REALPART_EXPR
3511 || TREE_CODE (t) == IMAGPART_EXPR)
3512 t = TREE_OPERAND (t, 0);
3521 /* Called via walk_trees. Verify tree sharing. */
3524 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3526 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3528 if (tree_node_can_be_shared (*tp))
3530 *walk_subtrees = false;
3534 if (pointer_set_insert (visited, *tp))
3541 /* Helper function for verify_gimple_tuples. */
3544 verify_gimple_tuples_1 (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
3545 void *data ATTRIBUTE_UNUSED)
3547 switch (TREE_CODE (*tp))
3550 error ("unexpected non-tuple");
3560 /* Verify that there are no trees that should have been converted to
3561 gimple tuples. Return true if T contains a node that should have
3562 been converted to a gimple tuple, but hasn't. */
3565 verify_gimple_tuples (tree t)
3567 return walk_tree (&t, verify_gimple_tuples_1, NULL, NULL) != NULL;
3570 static bool eh_error_found;
3572 verify_eh_throw_stmt_node (void **slot, void *data)
3574 struct throw_stmt_node *node = (struct throw_stmt_node *)*slot;
3575 struct pointer_set_t *visited = (struct pointer_set_t *) data;
3577 if (!pointer_set_contains (visited, node->stmt))
3579 error ("Dead STMT in EH table");
3580 debug_generic_stmt (node->stmt);
3581 eh_error_found = true;
3586 /* Verify the GIMPLE statement chain. */
3592 block_stmt_iterator bsi;
3594 struct pointer_set_t *visited, *visited_stmts;
3597 timevar_push (TV_TREE_STMT_VERIFY);
3598 visited = pointer_set_create ();
3599 visited_stmts = pointer_set_create ();
3606 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3608 int phi_num_args = PHI_NUM_ARGS (phi);
3610 pointer_set_insert (visited_stmts, phi);
3611 if (bb_for_stmt (phi) != bb)
3613 error ("bb_for_stmt (phi) is set to a wrong basic block");
3617 for (i = 0; i < phi_num_args; i++)
3619 tree t = PHI_ARG_DEF (phi, i);
3622 /* Addressable variables do have SSA_NAMEs but they
3623 are not considered gimple values. */
3624 if (TREE_CODE (t) != SSA_NAME
3625 && TREE_CODE (t) != FUNCTION_DECL
3626 && !is_gimple_val (t))
3628 error ("PHI def is not a GIMPLE value");
3629 debug_generic_stmt (phi);
3630 debug_generic_stmt (t);
3634 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3637 debug_generic_stmt (addr);
3641 addr = walk_tree (&t, verify_node_sharing, visited, NULL);
3644 error ("incorrect sharing of tree nodes");
3645 debug_generic_stmt (phi);
3646 debug_generic_stmt (addr);
3652 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3654 tree stmt = bsi_stmt (bsi);
3656 pointer_set_insert (visited_stmts, stmt);
3657 err |= verify_gimple_tuples (stmt);
3659 if (bb_for_stmt (stmt) != bb)
3661 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3666 err |= verify_stmt (stmt, bsi_end_p (bsi));
3667 addr = walk_tree (&stmt, verify_node_sharing, visited, NULL);
3670 error ("incorrect sharing of tree nodes");
3671 debug_generic_stmt (stmt);
3672 debug_generic_stmt (addr);
3677 eh_error_found = false;
3678 if (get_eh_throw_stmt_table (cfun))
3679 htab_traverse (get_eh_throw_stmt_table (cfun),
3680 verify_eh_throw_stmt_node,
3683 if (err | eh_error_found)
3684 internal_error ("verify_stmts failed");
3686 pointer_set_destroy (visited);
3687 pointer_set_destroy (visited_stmts);
3688 verify_histograms ();
3689 timevar_pop (TV_TREE_STMT_VERIFY);
3693 /* Verifies that the flow information is OK. */
3696 tree_verify_flow_info (void)
3700 block_stmt_iterator bsi;
3705 if (ENTRY_BLOCK_PTR->stmt_list)
3707 error ("ENTRY_BLOCK has a statement list associated with it");
3711 if (EXIT_BLOCK_PTR->stmt_list)
3713 error ("EXIT_BLOCK has a statement list associated with it");
3717 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3718 if (e->flags & EDGE_FALLTHRU)
3720 error ("fallthru to exit from bb %d", e->src->index);
3726 bool found_ctrl_stmt = false;
3730 /* Skip labels on the start of basic block. */
3731 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3733 tree prev_stmt = stmt;
3735 stmt = bsi_stmt (bsi);
3737 if (TREE_CODE (stmt) != LABEL_EXPR)
3740 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3742 error ("nonlocal label ");
3743 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3744 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3749 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3752 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3753 fprintf (stderr, " to block does not match in bb %d",
3758 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3759 != current_function_decl)
3762 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3763 fprintf (stderr, " has incorrect context in bb %d",
3769 /* Verify that body of basic block BB is free of control flow. */
3770 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3772 tree stmt = bsi_stmt (bsi);
3774 if (found_ctrl_stmt)
3776 error ("control flow in the middle of basic block %d",
3781 if (stmt_ends_bb_p (stmt))
3782 found_ctrl_stmt = true;
3784 if (TREE_CODE (stmt) == LABEL_EXPR)
3787 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3788 fprintf (stderr, " in the middle of basic block %d", bb->index);
3793 bsi = bsi_last (bb);
3794 if (bsi_end_p (bsi))
3797 stmt = bsi_stmt (bsi);
3799 err |= verify_eh_edges (stmt);
3801 if (is_ctrl_stmt (stmt))
3803 FOR_EACH_EDGE (e, ei, bb->succs)
3804 if (e->flags & EDGE_FALLTHRU)
3806 error ("fallthru edge after a control statement in bb %d",
3812 if (TREE_CODE (stmt) != COND_EXPR)
3814 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3815 after anything else but if statement. */
3816 FOR_EACH_EDGE (e, ei, bb->succs)
3817 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3819 error ("true/false edge after a non-COND_EXPR in bb %d",
3825 switch (TREE_CODE (stmt))
3831 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3832 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3834 error ("structured COND_EXPR at the end of bb %d", bb->index);
3838 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3840 if (!true_edge || !false_edge
3841 || !(true_edge->flags & EDGE_TRUE_VALUE)
3842 || !(false_edge->flags & EDGE_FALSE_VALUE)
3843 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3844 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3845 || EDGE_COUNT (bb->succs) >= 3)
3847 error ("wrong outgoing edge flags at end of bb %d",
3852 if (!has_label_p (true_edge->dest,
3853 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3855 error ("%<then%> label does not match edge at end of bb %d",
3860 if (!has_label_p (false_edge->dest,
3861 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3863 error ("%<else%> label does not match edge at end of bb %d",
3871 if (simple_goto_p (stmt))
3873 error ("explicit goto at end of bb %d", bb->index);
3878 /* FIXME. We should double check that the labels in the
3879 destination blocks have their address taken. */
3880 FOR_EACH_EDGE (e, ei, bb->succs)
3881 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3882 | EDGE_FALSE_VALUE))
3883 || !(e->flags & EDGE_ABNORMAL))
3885 error ("wrong outgoing edge flags at end of bb %d",
3893 if (!single_succ_p (bb)
3894 || (single_succ_edge (bb)->flags
3895 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3896 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3898 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3901 if (single_succ (bb) != EXIT_BLOCK_PTR)
3903 error ("return edge does not point to exit in bb %d",
3916 vec = SWITCH_LABELS (stmt);
3917 n = TREE_VEC_LENGTH (vec);
3919 /* Mark all the destination basic blocks. */
3920 for (i = 0; i < n; ++i)
3922 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3923 basic_block label_bb = label_to_block (lab);
3925 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3926 label_bb->aux = (void *)1;
3929 /* Verify that the case labels are sorted. */
3930 prev = TREE_VEC_ELT (vec, 0);
3931 for (i = 1; i < n - 1; ++i)
3933 tree c = TREE_VEC_ELT (vec, i);
3936 error ("found default case not at end of case vector");
3940 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3942 error ("case labels not sorted: ");
3943 print_generic_expr (stderr, prev, 0);
3944 fprintf (stderr," is greater than ");
3945 print_generic_expr (stderr, c, 0);
3946 fprintf (stderr," but comes before it.\n");
3951 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3953 error ("no default case found at end of case vector");
3957 FOR_EACH_EDGE (e, ei, bb->succs)
3961 error ("extra outgoing edge %d->%d",
3962 bb->index, e->dest->index);
3965 e->dest->aux = (void *)2;
3966 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3967 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3969 error ("wrong outgoing edge flags at end of bb %d",
3975 /* Check that we have all of them. */
3976 for (i = 0; i < n; ++i)
3978 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3979 basic_block label_bb = label_to_block (lab);
3981 if (label_bb->aux != (void *)2)
3983 error ("missing edge %i->%i",
3984 bb->index, label_bb->index);
3989 FOR_EACH_EDGE (e, ei, bb->succs)
3990 e->dest->aux = (void *)0;
3997 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3998 verify_dominators (CDI_DOMINATORS);
4004 /* Updates phi nodes after creating a forwarder block joined
4005 by edge FALLTHRU. */
4008 tree_make_forwarder_block (edge fallthru)
4012 basic_block dummy, bb;
4013 tree phi, new_phi, var;
4015 dummy = fallthru->src;
4016 bb = fallthru->dest;
4018 if (single_pred_p (bb))
4021 /* If we redirected a branch we must create new PHI nodes at the
4023 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
4025 var = PHI_RESULT (phi);
4026 new_phi = create_phi_node (var, bb);
4027 SSA_NAME_DEF_STMT (var) = new_phi;
4028 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
4029 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
4032 /* Ensure that the PHI node chain is in the same order. */
4033 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
4035 /* Add the arguments we have stored on edges. */
4036 FOR_EACH_EDGE (e, ei, bb->preds)
4041 flush_pending_stmts (e);
4046 /* Return a non-special label in the head of basic block BLOCK.
4047 Create one if it doesn't exist. */
4050 tree_block_label (basic_block bb)
4052 block_stmt_iterator i, s = bsi_start (bb);
4056 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4058 stmt = bsi_stmt (i);
4059 if (TREE_CODE (stmt) != LABEL_EXPR)
4061 label = LABEL_EXPR_LABEL (stmt);
4062 if (!DECL_NONLOCAL (label))
4065 bsi_move_before (&i, &s);
4070 label = create_artificial_label ();
4071 stmt = build1 (LABEL_EXPR, void_type_node, label);
4072 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4077 /* Attempt to perform edge redirection by replacing a possibly complex
4078 jump instruction by a goto or by removing the jump completely.
4079 This can apply only if all edges now point to the same block. The
4080 parameters and return values are equivalent to
4081 redirect_edge_and_branch. */
4084 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4086 basic_block src = e->src;
4087 block_stmt_iterator b;
4090 /* We can replace or remove a complex jump only when we have exactly
4092 if (EDGE_COUNT (src->succs) != 2
4093 /* Verify that all targets will be TARGET. Specifically, the
4094 edge that is not E must also go to TARGET. */
4095 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4101 stmt = bsi_stmt (b);
4103 if (TREE_CODE (stmt) == COND_EXPR
4104 || TREE_CODE (stmt) == SWITCH_EXPR)
4106 bsi_remove (&b, true);
4107 e = ssa_redirect_edge (e, target);
4108 e->flags = EDGE_FALLTHRU;
4116 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4117 edge representing the redirected branch. */
4120 tree_redirect_edge_and_branch (edge e, basic_block dest)
4122 basic_block bb = e->src;
4123 block_stmt_iterator bsi;
4127 if (e->flags & EDGE_ABNORMAL)
4130 if (e->src != ENTRY_BLOCK_PTR
4131 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4134 if (e->dest == dest)
4137 label = tree_block_label (dest);
4139 bsi = bsi_last (bb);
4140 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4142 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4145 stmt = (e->flags & EDGE_TRUE_VALUE
4146 ? COND_EXPR_THEN (stmt)
4147 : COND_EXPR_ELSE (stmt));
4148 GOTO_DESTINATION (stmt) = label;
4152 /* No non-abnormal edges should lead from a non-simple goto, and
4153 simple ones should be represented implicitly. */
4158 tree cases = get_cases_for_edge (e, stmt);
4160 /* If we have a list of cases associated with E, then use it
4161 as it's a lot faster than walking the entire case vector. */
4164 edge e2 = find_edge (e->src, dest);
4171 CASE_LABEL (cases) = label;
4172 cases = TREE_CHAIN (cases);
4175 /* If there was already an edge in the CFG, then we need
4176 to move all the cases associated with E to E2. */
4179 tree cases2 = get_cases_for_edge (e2, stmt);
4181 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4182 TREE_CHAIN (cases2) = first;
4187 tree vec = SWITCH_LABELS (stmt);
4188 size_t i, n = TREE_VEC_LENGTH (vec);
4190 for (i = 0; i < n; i++)
4192 tree elt = TREE_VEC_ELT (vec, i);
4194 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4195 CASE_LABEL (elt) = label;
4203 bsi_remove (&bsi, true);
4204 e->flags |= EDGE_FALLTHRU;
4208 /* Otherwise it must be a fallthru edge, and we don't need to
4209 do anything besides redirecting it. */
4210 gcc_assert (e->flags & EDGE_FALLTHRU);
4214 /* Update/insert PHI nodes as necessary. */
4216 /* Now update the edges in the CFG. */
4217 e = ssa_redirect_edge (e, dest);
4223 /* Simple wrapper, as we can always redirect fallthru edges. */
4226 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4228 e = tree_redirect_edge_and_branch (e, dest);
4235 /* Splits basic block BB after statement STMT (but at least after the
4236 labels). If STMT is NULL, BB is split just after the labels. */
4239 tree_split_block (basic_block bb, void *stmt)
4241 block_stmt_iterator bsi;
4242 tree_stmt_iterator tsi_tgt;
4248 new_bb = create_empty_bb (bb);
4250 /* Redirect the outgoing edges. */
4251 new_bb->succs = bb->succs;
4253 FOR_EACH_EDGE (e, ei, new_bb->succs)
4256 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4259 /* Move everything from BSI to the new basic block. */
4260 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4262 act = bsi_stmt (bsi);
4263 if (TREE_CODE (act) == LABEL_EXPR)
4276 if (bsi_end_p (bsi))
4279 /* Split the statement list - avoid re-creating new containers as this
4280 brings ugly quadratic memory consumption in the inliner.
4281 (We are still quadratic since we need to update stmt BB pointers,
4283 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4284 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4285 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4286 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4292 /* Moves basic block BB after block AFTER. */
4295 tree_move_block_after (basic_block bb, basic_block after)
4297 if (bb->prev_bb == after)
4301 link_block (bb, after);
4307 /* Return true if basic_block can be duplicated. */
4310 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4316 /* Create a duplicate of the basic block BB. NOTE: This does not
4317 preserve SSA form. */
4320 tree_duplicate_bb (basic_block bb)
4323 block_stmt_iterator bsi, bsi_tgt;
4326 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4328 /* Copy the PHI nodes. We ignore PHI node arguments here because
4329 the incoming edges have not been setup yet. */
4330 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4332 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4333 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4336 /* Keep the chain of PHI nodes in the same order so that they can be
4337 updated by ssa_redirect_edge. */
4338 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4340 bsi_tgt = bsi_start (new_bb);
4341 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4343 def_operand_p def_p;
4344 ssa_op_iter op_iter;
4348 stmt = bsi_stmt (bsi);
4349 if (TREE_CODE (stmt) == LABEL_EXPR)
4352 /* Create a new copy of STMT and duplicate STMT's virtual
4354 copy = unshare_expr (stmt);
4355 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4356 copy_virtual_operands (copy, stmt);
4357 region = lookup_stmt_eh_region (stmt);
4359 add_stmt_to_eh_region (copy, region);
4360 gimple_duplicate_stmt_histograms (cfun, copy, cfun, stmt);
4362 /* Create new names for all the definitions created by COPY and
4363 add replacement mappings for each new name. */
4364 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4365 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4372 /* Basic block BB_COPY was created by code duplication. Add phi node
4373 arguments for edges going out of BB_COPY. The blocks that were
4374 duplicated have BB_DUPLICATED set. */
4377 add_phi_args_after_copy_bb (basic_block bb_copy)
4379 basic_block bb, dest;
4382 tree phi, phi_copy, phi_next, def;
4384 bb = get_bb_original (bb_copy);
4386 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4388 if (!phi_nodes (e_copy->dest))
4391 if (e_copy->dest->flags & BB_DUPLICATED)
4392 dest = get_bb_original (e_copy->dest);
4394 dest = e_copy->dest;
4396 e = find_edge (bb, dest);
4399 /* During loop unrolling the target of the latch edge is copied.
4400 In this case we are not looking for edge to dest, but to
4401 duplicated block whose original was dest. */
4402 FOR_EACH_EDGE (e, ei, bb->succs)
4403 if ((e->dest->flags & BB_DUPLICATED)
4404 && get_bb_original (e->dest) == dest)
4407 gcc_assert (e != NULL);
4410 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4412 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4414 phi_next = PHI_CHAIN (phi);
4415 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4416 add_phi_arg (phi_copy, def, e_copy);
4421 /* Blocks in REGION_COPY array of length N_REGION were created by
4422 duplication of basic blocks. Add phi node arguments for edges
4423 going from these blocks. */
4426 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4430 for (i = 0; i < n_region; i++)
4431 region_copy[i]->flags |= BB_DUPLICATED;
4433 for (i = 0; i < n_region; i++)
4434 add_phi_args_after_copy_bb (region_copy[i]);
4436 for (i = 0; i < n_region; i++)
4437 region_copy[i]->flags &= ~BB_DUPLICATED;
4440 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4441 important exit edge EXIT. By important we mean that no SSA name defined
4442 inside region is live over the other exit edges of the region. All entry
4443 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4444 to the duplicate of the region. SSA form, dominance and loop information
4445 is updated. The new basic blocks are stored to REGION_COPY in the same
4446 order as they had in REGION, provided that REGION_COPY is not NULL.
4447 The function returns false if it is unable to copy the region,
4451 tree_duplicate_sese_region (edge entry, edge exit,
4452 basic_block *region, unsigned n_region,
4453 basic_block *region_copy)
4456 bool free_region_copy = false, copying_header = false;
4457 struct loop *loop = entry->dest->loop_father;
4461 int total_freq = 0, entry_freq = 0;
4462 gcov_type total_count = 0, entry_count = 0;
4464 if (!can_copy_bbs_p (region, n_region))
4467 /* Some sanity checking. Note that we do not check for all possible
4468 missuses of the functions. I.e. if you ask to copy something weird,
4469 it will work, but the state of structures probably will not be
4471 for (i = 0; i < n_region; i++)
4473 /* We do not handle subloops, i.e. all the blocks must belong to the
4475 if (region[i]->loop_father != loop)
4478 if (region[i] != entry->dest
4479 && region[i] == loop->header)
4485 /* In case the function is used for loop header copying (which is the primary
4486 use), ensure that EXIT and its copy will be new latch and entry edges. */
4487 if (loop->header == entry->dest)
4489 copying_header = true;
4490 loop->copy = loop->outer;
4492 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4495 for (i = 0; i < n_region; i++)
4496 if (region[i] != exit->src
4497 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4503 region_copy = XNEWVEC (basic_block, n_region);
4504 free_region_copy = true;
4507 gcc_assert (!need_ssa_update_p ());
4509 /* Record blocks outside the region that are dominated by something
4511 doms = XNEWVEC (basic_block, n_basic_blocks);
4512 initialize_original_copy_tables ();
4514 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4516 if (entry->dest->count)
4518 total_count = entry->dest->count;
4519 entry_count = entry->count;
4520 /* Fix up corner cases, to avoid division by zero or creation of negative
4522 if (entry_count > total_count)
4523 entry_count = total_count;
4527 total_freq = entry->dest->frequency;
4528 entry_freq = EDGE_FREQUENCY (entry);
4529 /* Fix up corner cases, to avoid division by zero or creation of negative
4531 if (total_freq == 0)
4533 else if (entry_freq > total_freq)
4534 entry_freq = total_freq;
4537 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4538 split_edge_bb_loc (entry));
4541 scale_bbs_frequencies_gcov_type (region, n_region,
4542 total_count - entry_count,
4544 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4549 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4551 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4556 loop->header = exit->dest;
4557 loop->latch = exit->src;
4560 /* Redirect the entry and add the phi node arguments. */
4561 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4562 gcc_assert (redirected != NULL);
4563 flush_pending_stmts (entry);
4565 /* Concerning updating of dominators: We must recount dominators
4566 for entry block and its copy. Anything that is outside of the
4567 region, but was dominated by something inside needs recounting as
4569 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4570 doms[n_doms++] = get_bb_original (entry->dest);
4571 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4574 /* Add the other PHI node arguments. */
4575 add_phi_args_after_copy (region_copy, n_region);
4577 /* Update the SSA web. */
4578 update_ssa (TODO_update_ssa);
4580 if (free_region_copy)
4583 free_original_copy_tables ();
4588 DEF_VEC_P(basic_block);
4589 DEF_VEC_ALLOC_P(basic_block,heap);
4592 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4593 adding blocks when the dominator traversal reaches EXIT. This
4594 function silently assumes that ENTRY strictly dominates EXIT. */
4597 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4598 VEC(basic_block,heap) **bbs_p)
4602 for (son = first_dom_son (CDI_DOMINATORS, entry);
4604 son = next_dom_son (CDI_DOMINATORS, son))
4606 VEC_safe_push (basic_block, heap, *bbs_p, son);
4608 gather_blocks_in_sese_region (son, exit, bbs_p);
4618 bitmap vars_to_remove;
4619 htab_t new_label_map;
4623 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4624 contained in *TP and change the DECL_CONTEXT of every local
4625 variable referenced in *TP. */
4628 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4630 struct move_stmt_d *p = (struct move_stmt_d *) data;
4634 && (EXPR_P (t) || GIMPLE_STMT_P (t)))
4635 TREE_BLOCK (t) = p->block;
4637 if (OMP_DIRECTIVE_P (t)
4638 && TREE_CODE (t) != OMP_RETURN
4639 && TREE_CODE (t) != OMP_CONTINUE)
4641 /* Do not remap variables inside OMP directives. Variables
4642 referenced in clauses and directive header belong to the
4643 parent function and should not be moved into the child
4645 bool save_remap_decls_p = p->remap_decls_p;
4646 p->remap_decls_p = false;
4649 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4651 p->remap_decls_p = save_remap_decls_p;
4653 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4655 if (TREE_CODE (t) == LABEL_DECL)
4657 if (p->new_label_map)
4659 struct tree_map in, *out;
4661 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4666 DECL_CONTEXT (t) = p->to_context;
4668 else if (p->remap_decls_p)
4670 DECL_CONTEXT (t) = p->to_context;
4672 if (TREE_CODE (t) == VAR_DECL)
4674 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4675 f->unexpanded_var_list
4676 = tree_cons (0, t, f->unexpanded_var_list);
4678 /* Mark T to be removed from the original function,
4679 otherwise it will be given a DECL_RTL when the
4680 original function is expanded. */
4681 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4685 else if (TYPE_P (t))
4692 /* Move basic block BB from function CFUN to function DEST_FN. The
4693 block is moved out of the original linked list and placed after
4694 block AFTER in the new list. Also, the block is removed from the
4695 original array of blocks and placed in DEST_FN's array of blocks.
4696 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4697 updated to reflect the moved edges.
4699 On exit, local variables that need to be removed from
4700 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4703 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4704 basic_block after, bool update_edge_count_p,
4705 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4707 struct control_flow_graph *cfg;
4710 block_stmt_iterator si;
4711 struct move_stmt_d d;
4712 unsigned old_len, new_len;
4714 /* Link BB to the new linked list. */
4715 move_block_after (bb, after);
4717 /* Update the edge count in the corresponding flowgraphs. */
4718 if (update_edge_count_p)
4719 FOR_EACH_EDGE (e, ei, bb->succs)
4721 cfun->cfg->x_n_edges--;
4722 dest_cfun->cfg->x_n_edges++;
4725 /* Remove BB from the original basic block array. */
4726 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4727 cfun->cfg->x_n_basic_blocks--;
4729 /* Grow DEST_CFUN's basic block array if needed. */
4730 cfg = dest_cfun->cfg;
4731 cfg->x_n_basic_blocks++;
4732 if (bb->index > cfg->x_last_basic_block)
4733 cfg->x_last_basic_block = bb->index;
4735 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4736 if ((unsigned) cfg->x_last_basic_block >= old_len)
4738 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4739 VEC_safe_grow_cleared (basic_block, gc, cfg->x_basic_block_info,
4743 VEC_replace (basic_block, cfg->x_basic_block_info,
4744 cfg->x_last_basic_block, bb);
4746 /* The statements in BB need to be associated with a new TREE_BLOCK.
4747 Labels need to be associated with a new label-to-block map. */
4748 memset (&d, 0, sizeof (d));
4749 d.vars_to_remove = vars_to_remove;
4751 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4753 tree stmt = bsi_stmt (si);
4756 d.from_context = cfun->decl;
4757 d.to_context = dest_cfun->decl;
4758 d.remap_decls_p = true;
4759 d.new_label_map = new_label_map;
4760 if (TREE_BLOCK (stmt))
4761 d.block = DECL_INITIAL (dest_cfun->decl);
4763 walk_tree (&stmt, move_stmt_r, &d, NULL);
4765 if (TREE_CODE (stmt) == LABEL_EXPR)
4767 tree label = LABEL_EXPR_LABEL (stmt);
4768 int uid = LABEL_DECL_UID (label);
4770 gcc_assert (uid > -1);
4772 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4773 if (old_len <= (unsigned) uid)
4775 new_len = 3 * uid / 2;
4776 VEC_safe_grow_cleared (basic_block, gc,
4777 cfg->x_label_to_block_map, new_len);
4780 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4781 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4783 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4785 if (uid >= dest_cfun->last_label_uid)
4786 dest_cfun->last_label_uid = uid + 1;
4788 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4789 TREE_OPERAND (stmt, 0) =
4790 build_int_cst (NULL_TREE,
4791 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4794 region = lookup_stmt_eh_region (stmt);
4797 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4798 remove_stmt_from_eh_region (stmt);
4799 gimple_duplicate_stmt_histograms (dest_cfun, stmt, cfun, stmt);
4800 gimple_remove_stmt_histograms (cfun, stmt);
4805 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4806 the outermost EH region. Use REGION as the incoming base EH region. */
4809 find_outermost_region_in_block (struct function *src_cfun,
4810 basic_block bb, int region)
4812 block_stmt_iterator si;
4814 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4816 tree stmt = bsi_stmt (si);
4819 if (TREE_CODE (stmt) == RESX_EXPR)
4820 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4822 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4823 if (stmt_region > 0)
4826 region = stmt_region;
4827 else if (stmt_region != region)
4829 region = eh_region_outermost (src_cfun, stmt_region, region);
4830 gcc_assert (region != -1);
4839 new_label_mapper (tree decl, void *data)
4841 htab_t hash = (htab_t) data;
4845 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4847 m = xmalloc (sizeof (struct tree_map));
4848 m->hash = DECL_UID (decl);
4850 m->to = create_artificial_label ();
4851 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4853 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4854 gcc_assert (*slot == NULL);
4861 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4862 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4863 single basic block in the original CFG and the new basic block is
4864 returned. DEST_CFUN must not have a CFG yet.
4866 Note that the region need not be a pure SESE region. Blocks inside
4867 the region may contain calls to abort/exit. The only restriction
4868 is that ENTRY_BB should be the only entry point and it must
4871 All local variables referenced in the region are assumed to be in
4872 the corresponding BLOCK_VARS and unexpanded variable lists
4873 associated with DEST_CFUN. */
4876 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4877 basic_block exit_bb)
4879 VEC(basic_block,heap) *bbs;
4880 basic_block after, bb, *entry_pred, *exit_succ;
4881 struct function *saved_cfun;
4882 int *entry_flag, *exit_flag, eh_offset;
4883 unsigned i, num_entry_edges, num_exit_edges;
4886 bitmap vars_to_remove;
4887 htab_t new_label_map;
4891 /* Collect all the blocks in the region. Manually add ENTRY_BB
4892 because it won't be added by dfs_enumerate_from. */
4893 calculate_dominance_info (CDI_DOMINATORS);
4895 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4897 gcc_assert (entry_bb != exit_bb
4899 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4902 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4903 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4905 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4906 the predecessor edges to ENTRY_BB and the successor edges to
4907 EXIT_BB so that we can re-attach them to the new basic block that
4908 will replace the region. */
4909 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4910 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4911 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4913 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4915 entry_flag[i] = e->flags;
4916 entry_pred[i++] = e->src;
4922 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4923 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4924 sizeof (basic_block));
4925 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4927 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4929 exit_flag[i] = e->flags;
4930 exit_succ[i++] = e->dest;
4941 /* Switch context to the child function to initialize DEST_FN's CFG. */
4942 gcc_assert (dest_cfun->cfg == NULL);
4945 init_empty_tree_cfg ();
4947 /* Initialize EH information for the new function. */
4949 new_label_map = NULL;
4954 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4955 region = find_outermost_region_in_block (saved_cfun, bb, region);
4957 init_eh_for_function ();
4960 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4961 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4962 new_label_map, region, 0);
4968 /* Move blocks from BBS into DEST_CFUN. */
4969 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4970 after = dest_cfun->cfg->x_entry_block_ptr;
4971 vars_to_remove = BITMAP_ALLOC (NULL);
4972 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4974 /* No need to update edge counts on the last block. It has
4975 already been updated earlier when we detached the region from
4976 the original CFG. */
4977 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4978 new_label_map, eh_offset);
4983 htab_delete (new_label_map);
4985 /* Remove the variables marked in VARS_TO_REMOVE from
4986 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4987 DECL_RTL in the context of CFUN. */
4988 if (!bitmap_empty_p (vars_to_remove))
4992 for (p = &cfun->unexpanded_var_list; *p; )
4994 tree var = TREE_VALUE (*p);
4995 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4997 *p = TREE_CHAIN (*p);
5001 p = &TREE_CHAIN (*p);
5005 BITMAP_FREE (vars_to_remove);
5007 /* Rewire the entry and exit blocks. The successor to the entry
5008 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
5009 the child function. Similarly, the predecessor of DEST_FN's
5010 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
5011 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
5012 various CFG manipulation function get to the right CFG.
5014 FIXME, this is silly. The CFG ought to become a parameter to
5017 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
5019 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
5022 /* Back in the original function, the SESE region has disappeared,
5023 create a new basic block in its place. */
5024 bb = create_empty_bb (entry_pred[0]);
5025 for (i = 0; i < num_entry_edges; i++)
5026 make_edge (entry_pred[i], bb, entry_flag[i]);
5028 for (i = 0; i < num_exit_edges; i++)
5029 make_edge (bb, exit_succ[i], exit_flag[i]);
5038 free_dominance_info (CDI_DOMINATORS);
5039 free_dominance_info (CDI_POST_DOMINATORS);
5040 VEC_free (basic_block, heap, bbs);
5046 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5049 dump_function_to_file (tree fn, FILE *file, int flags)
5051 tree arg, vars, var;
5052 bool ignore_topmost_bind = false, any_var = false;
5055 struct function *saved_cfun;
5057 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5059 arg = DECL_ARGUMENTS (fn);
5062 print_generic_expr (file, arg, dump_flags);
5063 if (TREE_CHAIN (arg))
5064 fprintf (file, ", ");
5065 arg = TREE_CHAIN (arg);
5067 fprintf (file, ")\n");
5069 if (flags & TDF_DETAILS)
5070 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5071 if (flags & TDF_RAW)
5073 dump_node (fn, TDF_SLIM | flags, file);
5077 /* Switch CFUN to point to FN. */
5079 cfun = DECL_STRUCT_FUNCTION (fn);
5081 /* When GIMPLE is lowered, the variables are no longer available in
5082 BIND_EXPRs, so display them separately. */
5083 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5085 ignore_topmost_bind = true;
5087 fprintf (file, "{\n");
5088 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5090 var = TREE_VALUE (vars);
5092 print_generic_decl (file, var, flags);
5093 fprintf (file, "\n");
5099 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5101 /* Make a CFG based dump. */
5102 check_bb_profile (ENTRY_BLOCK_PTR, file);
5103 if (!ignore_topmost_bind)
5104 fprintf (file, "{\n");
5106 if (any_var && n_basic_blocks)
5107 fprintf (file, "\n");
5110 dump_generic_bb (file, bb, 2, flags);
5112 fprintf (file, "}\n");
5113 check_bb_profile (EXIT_BLOCK_PTR, file);
5119 /* Make a tree based dump. */
5120 chain = DECL_SAVED_TREE (fn);
5122 if (chain && TREE_CODE (chain) == BIND_EXPR)
5124 if (ignore_topmost_bind)
5126 chain = BIND_EXPR_BODY (chain);
5134 if (!ignore_topmost_bind)
5135 fprintf (file, "{\n");
5140 fprintf (file, "\n");
5142 print_generic_stmt_indented (file, chain, flags, indent);
5143 if (ignore_topmost_bind)
5144 fprintf (file, "}\n");
5147 fprintf (file, "\n\n");
5154 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5157 debug_function (tree fn, int flags)
5159 dump_function_to_file (fn, stderr, flags);
5163 /* Pretty print of the loops intermediate representation. */
5164 static void print_loop (FILE *, struct loop *, int);
5165 static void print_pred_bbs (FILE *, basic_block bb);
5166 static void print_succ_bbs (FILE *, basic_block bb);
5169 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5172 print_pred_bbs (FILE *file, basic_block bb)
5177 FOR_EACH_EDGE (e, ei, bb->preds)
5178 fprintf (file, "bb_%d ", e->src->index);
5182 /* Print on FILE the indexes for the successors of basic_block BB. */
5185 print_succ_bbs (FILE *file, basic_block bb)
5190 FOR_EACH_EDGE (e, ei, bb->succs)
5191 fprintf (file, "bb_%d ", e->dest->index);
5195 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5198 print_loop (FILE *file, struct loop *loop, int indent)
5206 s_indent = (char *) alloca ((size_t) indent + 1);
5207 memset ((void *) s_indent, ' ', (size_t) indent);
5208 s_indent[indent] = '\0';
5210 /* Print the loop's header. */
5211 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5213 /* Print the loop's body. */
5214 fprintf (file, "%s{\n", s_indent);
5216 if (bb->loop_father == loop)
5218 /* Print the basic_block's header. */
5219 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5220 print_pred_bbs (file, bb);
5221 fprintf (file, "}, succs = {");
5222 print_succ_bbs (file, bb);
5223 fprintf (file, "})\n");
5225 /* Print the basic_block's body. */
5226 fprintf (file, "%s {\n", s_indent);
5227 tree_dump_bb (bb, file, indent + 4);
5228 fprintf (file, "%s }\n", s_indent);
5231 print_loop (file, loop->inner, indent + 2);
5232 fprintf (file, "%s}\n", s_indent);
5233 print_loop (file, loop->next, indent);
5237 /* Follow a CFG edge from the entry point of the program, and on entry
5238 of a loop, pretty print the loop structure on FILE. */
5241 print_loop_ir (FILE *file)
5245 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5246 if (bb && bb->loop_father)
5247 print_loop (file, bb->loop_father, 0);
5251 /* Debugging loops structure at tree level. */
5254 debug_loop_ir (void)
5256 print_loop_ir (stderr);
5260 /* Return true if BB ends with a call, possibly followed by some
5261 instructions that must stay with the call. Return false,
5265 tree_block_ends_with_call_p (basic_block bb)
5267 block_stmt_iterator bsi = bsi_last (bb);
5268 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5272 /* Return true if BB ends with a conditional branch. Return false,
5276 tree_block_ends_with_condjump_p (basic_block bb)
5278 tree stmt = last_stmt (bb);
5279 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5283 /* Return true if we need to add fake edge to exit at statement T.
5284 Helper function for tree_flow_call_edges_add. */
5287 need_fake_edge_p (tree t)
5291 /* NORETURN and LONGJMP calls already have an edge to exit.
5292 CONST and PURE calls do not need one.
5293 We don't currently check for CONST and PURE here, although
5294 it would be a good idea, because those attributes are
5295 figured out from the RTL in mark_constant_function, and
5296 the counter incrementation code from -fprofile-arcs
5297 leads to different results from -fbranch-probabilities. */
5298 call = get_call_expr_in (t);
5300 && !(call_expr_flags (call) & ECF_NORETURN))
5303 if (TREE_CODE (t) == ASM_EXPR
5304 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5311 /* Add fake edges to the function exit for any non constant and non
5312 noreturn calls, volatile inline assembly in the bitmap of blocks
5313 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5314 the number of blocks that were split.
5316 The goal is to expose cases in which entering a basic block does
5317 not imply that all subsequent instructions must be executed. */
5320 tree_flow_call_edges_add (sbitmap blocks)
5323 int blocks_split = 0;
5324 int last_bb = last_basic_block;
5325 bool check_last_block = false;
5327 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5331 check_last_block = true;
5333 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5335 /* In the last basic block, before epilogue generation, there will be
5336 a fallthru edge to EXIT. Special care is required if the last insn
5337 of the last basic block is a call because make_edge folds duplicate
5338 edges, which would result in the fallthru edge also being marked
5339 fake, which would result in the fallthru edge being removed by
5340 remove_fake_edges, which would result in an invalid CFG.
5342 Moreover, we can't elide the outgoing fake edge, since the block
5343 profiler needs to take this into account in order to solve the minimal
5344 spanning tree in the case that the call doesn't return.
5346 Handle this by adding a dummy instruction in a new last basic block. */
5347 if (check_last_block)
5349 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5350 block_stmt_iterator bsi = bsi_last (bb);
5352 if (!bsi_end_p (bsi))
5355 if (t && need_fake_edge_p (t))
5359 e = find_edge (bb, EXIT_BLOCK_PTR);
5362 bsi_insert_on_edge (e, build_empty_stmt ());
5363 bsi_commit_edge_inserts ();
5368 /* Now add fake edges to the function exit for any non constant
5369 calls since there is no way that we can determine if they will
5371 for (i = 0; i < last_bb; i++)
5373 basic_block bb = BASIC_BLOCK (i);
5374 block_stmt_iterator bsi;
5375 tree stmt, last_stmt;
5380 if (blocks && !TEST_BIT (blocks, i))
5383 bsi = bsi_last (bb);
5384 if (!bsi_end_p (bsi))
5386 last_stmt = bsi_stmt (bsi);
5389 stmt = bsi_stmt (bsi);
5390 if (need_fake_edge_p (stmt))
5393 /* The handling above of the final block before the
5394 epilogue should be enough to verify that there is
5395 no edge to the exit block in CFG already.
5396 Calling make_edge in such case would cause us to
5397 mark that edge as fake and remove it later. */
5398 #ifdef ENABLE_CHECKING
5399 if (stmt == last_stmt)
5401 e = find_edge (bb, EXIT_BLOCK_PTR);
5402 gcc_assert (e == NULL);
5406 /* Note that the following may create a new basic block
5407 and renumber the existing basic blocks. */
5408 if (stmt != last_stmt)
5410 e = split_block (bb, stmt);
5414 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5418 while (!bsi_end_p (bsi));
5423 verify_flow_info ();
5425 return blocks_split;
5428 /* Purge dead abnormal call edges from basic block BB. */
5431 tree_purge_dead_abnormal_call_edges (basic_block bb)
5433 bool changed = tree_purge_dead_eh_edges (bb);
5435 if (current_function_has_nonlocal_label)
5437 tree stmt = last_stmt (bb);
5441 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5442 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5444 if (e->flags & EDGE_ABNORMAL)
5453 /* See tree_purge_dead_eh_edges below. */
5455 free_dominance_info (CDI_DOMINATORS);
5461 /* Purge dead EH edges from basic block BB. */
5464 tree_purge_dead_eh_edges (basic_block bb)
5466 bool changed = false;
5469 tree stmt = last_stmt (bb);
5471 if (stmt && tree_can_throw_internal (stmt))
5474 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5476 if (e->flags & EDGE_EH)
5485 /* Removal of dead EH edges might change dominators of not
5486 just immediate successors. E.g. when bb1 is changed so that
5487 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5488 eh edges purged by this function in:
5500 idom(bb5) must be recomputed. For now just free the dominance
5503 free_dominance_info (CDI_DOMINATORS);
5509 tree_purge_all_dead_eh_edges (bitmap blocks)
5511 bool changed = false;
5515 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5517 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5523 /* This function is called whenever a new edge is created or
5527 tree_execute_on_growing_pred (edge e)
5529 basic_block bb = e->dest;
5532 reserve_phi_args_for_new_edge (bb);
5535 /* This function is called immediately before edge E is removed from
5536 the edge vector E->dest->preds. */
5539 tree_execute_on_shrinking_pred (edge e)
5541 if (phi_nodes (e->dest))
5542 remove_phi_args (e);
5545 /*---------------------------------------------------------------------------
5546 Helper functions for Loop versioning
5547 ---------------------------------------------------------------------------*/
5549 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5550 of 'first'. Both of them are dominated by 'new_head' basic block. When
5551 'new_head' was created by 'second's incoming edge it received phi arguments
5552 on the edge by split_edge(). Later, additional edge 'e' was created to
5553 connect 'new_head' and 'first'. Now this routine adds phi args on this
5554 additional edge 'e' that new_head to second edge received as part of edge
5559 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5560 basic_block new_head, edge e)
5563 edge e2 = find_edge (new_head, second);
5565 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5566 edge, we should always have an edge from NEW_HEAD to SECOND. */
5567 gcc_assert (e2 != NULL);
5569 /* Browse all 'second' basic block phi nodes and add phi args to
5570 edge 'e' for 'first' head. PHI args are always in correct order. */
5572 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5574 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5576 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5577 add_phi_arg (phi1, def, e);
5581 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5582 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5583 the destination of the ELSE part. */
5585 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5586 basic_block cond_bb, void *cond_e)
5588 block_stmt_iterator bsi;
5589 tree goto1 = NULL_TREE;
5590 tree goto2 = NULL_TREE;
5591 tree new_cond_expr = NULL_TREE;
5592 tree cond_expr = (tree) cond_e;
5595 /* Build new conditional expr */
5596 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5597 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5598 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5600 /* Add new cond in cond_bb. */
5601 bsi = bsi_start (cond_bb);
5602 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5603 /* Adjust edges appropriately to connect new head with first head
5604 as well as second head. */
5605 e0 = single_succ_edge (cond_bb);
5606 e0->flags &= ~EDGE_FALLTHRU;
5607 e0->flags |= EDGE_FALSE_VALUE;
5610 struct cfg_hooks tree_cfg_hooks = {
5612 tree_verify_flow_info,
5613 tree_dump_bb, /* dump_bb */
5614 create_bb, /* create_basic_block */
5615 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5616 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5617 remove_bb, /* delete_basic_block */
5618 tree_split_block, /* split_block */
5619 tree_move_block_after, /* move_block_after */
5620 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5621 tree_merge_blocks, /* merge_blocks */
5622 tree_predict_edge, /* predict_edge */
5623 tree_predicted_by_p, /* predicted_by_p */
5624 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5625 tree_duplicate_bb, /* duplicate_block */
5626 tree_split_edge, /* split_edge */
5627 tree_make_forwarder_block, /* make_forward_block */
5628 NULL, /* tidy_fallthru_edge */
5629 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5630 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5631 tree_flow_call_edges_add, /* flow_call_edges_add */
5632 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5633 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5634 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5635 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5636 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5637 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5638 flush_pending_stmts /* flush_pending_stmts */
5642 /* Split all critical edges. */
5645 split_critical_edges (void)
5651 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5652 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5653 mappings around the calls to split_edge. */
5654 start_recording_case_labels ();
5657 FOR_EACH_EDGE (e, ei, bb->succs)
5658 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5663 end_recording_case_labels ();
5667 struct tree_opt_pass pass_split_crit_edges =
5669 "crited", /* name */
5671 split_critical_edges, /* execute */
5674 0, /* static_pass_number */
5675 TV_TREE_SPLIT_EDGES, /* tv_id */
5676 PROP_cfg, /* properties required */
5677 PROP_no_crit_edges, /* properties_provided */
5678 0, /* properties_destroyed */
5679 0, /* todo_flags_start */
5680 TODO_dump_func, /* todo_flags_finish */
5685 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5686 a temporary, make sure and register it to be renamed if necessary,
5687 and finally return the temporary. Put the statements to compute
5688 EXP before the current statement in BSI. */
5691 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5693 tree t, new_stmt, orig_stmt;
5695 if (is_gimple_val (exp))
5698 t = make_rename_temp (type, NULL);
5699 new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, t, exp);
5701 orig_stmt = bsi_stmt (*bsi);
5702 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5703 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5705 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5706 if (gimple_in_ssa_p (cfun))
5707 mark_symbols_for_renaming (new_stmt);
5712 /* Build a ternary operation and gimplify it. Emit code before BSI.
5713 Return the gimple_val holding the result. */
5716 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5717 tree type, tree a, tree b, tree c)
5721 ret = fold_build3 (code, type, a, b, c);
5724 return gimplify_val (bsi, type, ret);
5727 /* Build a binary operation and gimplify it. Emit code before BSI.
5728 Return the gimple_val holding the result. */
5731 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5732 tree type, tree a, tree b)
5736 ret = fold_build2 (code, type, a, b);
5739 return gimplify_val (bsi, type, ret);
5742 /* Build a unary operation and gimplify it. Emit code before BSI.
5743 Return the gimple_val holding the result. */
5746 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5751 ret = fold_build1 (code, type, a);
5754 return gimplify_val (bsi, type, ret);
5759 /* Emit return warnings. */
5762 execute_warn_function_return (void)
5764 #ifdef USE_MAPPED_LOCATION
5765 source_location location;
5773 /* If we have a path to EXIT, then we do return. */
5774 if (TREE_THIS_VOLATILE (cfun->decl)
5775 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5777 #ifdef USE_MAPPED_LOCATION
5778 location = UNKNOWN_LOCATION;
5782 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5784 last = last_stmt (e->src);
5785 if (TREE_CODE (last) == RETURN_EXPR
5786 #ifdef USE_MAPPED_LOCATION
5787 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5789 && (locus = EXPR_LOCUS (last)) != NULL)
5793 #ifdef USE_MAPPED_LOCATION
5794 if (location == UNKNOWN_LOCATION)
5795 location = cfun->function_end_locus;
5796 warning (0, "%H%<noreturn%> function does return", &location);
5799 locus = &cfun->function_end_locus;
5800 warning (0, "%H%<noreturn%> function does return", locus);
5804 /* If we see "return;" in some basic block, then we do reach the end
5805 without returning a value. */
5806 else if (warn_return_type
5807 && !TREE_NO_WARNING (cfun->decl)
5808 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5809 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5811 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5813 tree last = last_stmt (e->src);
5814 if (TREE_CODE (last) == RETURN_EXPR
5815 && TREE_OPERAND (last, 0) == NULL
5816 && !TREE_NO_WARNING (last))
5818 #ifdef USE_MAPPED_LOCATION
5819 location = EXPR_LOCATION (last);
5820 if (location == UNKNOWN_LOCATION)
5821 location = cfun->function_end_locus;
5822 warning (0, "%Hcontrol reaches end of non-void function", &location);
5824 locus = EXPR_LOCUS (last);
5826 locus = &cfun->function_end_locus;
5827 warning (0, "%Hcontrol reaches end of non-void function", locus);
5829 TREE_NO_WARNING (cfun->decl) = 1;
5838 /* Given a basic block B which ends with a conditional and has
5839 precisely two successors, determine which of the edges is taken if
5840 the conditional is true and which is taken if the conditional is
5841 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5844 extract_true_false_edges_from_block (basic_block b,
5848 edge e = EDGE_SUCC (b, 0);
5850 if (e->flags & EDGE_TRUE_VALUE)
5853 *false_edge = EDGE_SUCC (b, 1);
5858 *true_edge = EDGE_SUCC (b, 1);
5862 struct tree_opt_pass pass_warn_function_return =
5866 execute_warn_function_return, /* execute */
5869 0, /* static_pass_number */
5871 PROP_cfg, /* properties_required */
5872 0, /* properties_provided */
5873 0, /* properties_destroyed */
5874 0, /* todo_flags_start */
5875 0, /* todo_flags_finish */
5879 /* Emit noreturn warnings. */
5882 execute_warn_function_noreturn (void)
5884 if (warn_missing_noreturn
5885 && !TREE_THIS_VOLATILE (cfun->decl)
5886 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5887 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5888 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5889 "for attribute %<noreturn%>",
5894 struct tree_opt_pass pass_warn_function_noreturn =
5898 execute_warn_function_noreturn, /* execute */
5901 0, /* static_pass_number */
5903 PROP_cfg, /* properties_required */
5904 0, /* properties_provided */
5905 0, /* properties_destroyed */
5906 0, /* todo_flags_start */
5907 0, /* todo_flags_finish */