1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
48 #include "tree-ssa-propagate.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity = 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 struct edge_to_cases_elt
73 /* The edge itself. Necessary for hashing and equality tests. */
76 /* The case labels associated with this edge. We link these up via
77 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
78 when we destroy the hash table. This prevents problems when copying
83 static htab_t edge_to_cases;
88 long num_merged_labels;
91 static struct cfg_stats_d cfg_stats;
93 /* Nonzero if we found a computed goto while building basic blocks. */
94 static bool found_computed_goto;
96 /* Basic blocks and flowgraphs. */
97 static basic_block create_bb (void *, void *, basic_block);
98 static void make_blocks (tree);
99 static void factor_computed_gotos (void);
102 static void make_edges (void);
103 static void make_cond_expr_edges (basic_block);
104 static void make_switch_expr_edges (basic_block);
105 static void make_goto_expr_edges (basic_block);
106 static edge tree_redirect_edge_and_branch (edge, basic_block);
107 static edge tree_try_redirect_by_replacing_jump (edge, basic_block);
108 static unsigned int split_critical_edges (void);
110 /* Various helpers. */
111 static inline bool stmt_starts_bb_p (tree, tree);
112 static int tree_verify_flow_info (void);
113 static void tree_make_forwarder_block (edge);
114 static void tree_cfg2vcg (FILE *);
115 static inline void change_bb_for_stmt (tree t, basic_block bb);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block, basic_block);
119 static bool tree_can_merge_blocks_p (basic_block, basic_block);
120 static void remove_bb (basic_block);
121 static edge find_taken_edge_computed_goto (basic_block, tree);
122 static edge find_taken_edge_cond_expr (basic_block, tree);
123 static edge find_taken_edge_switch_expr (basic_block, tree);
124 static tree find_case_label_for_value (tree, tree);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status = PROFILE_ABSENT;
132 n_basic_blocks = NUM_FIXED_BLOCKS;
133 last_basic_block = NUM_FIXED_BLOCKS;
134 basic_block_info = VEC_alloc (basic_block, gc, initial_cfg_capacity);
135 VEC_safe_grow (basic_block, gc, basic_block_info, initial_cfg_capacity);
136 memset (VEC_address (basic_block, basic_block_info), 0,
137 sizeof (basic_block) * initial_cfg_capacity);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map = VEC_alloc (basic_block, gc, initial_cfg_capacity);
141 VEC_safe_grow (basic_block, gc, label_to_block_map, initial_cfg_capacity);
142 memset (VEC_address (basic_block, label_to_block_map),
143 0, sizeof (basic_block) * initial_cfg_capacity);
145 SET_BASIC_BLOCK (ENTRY_BLOCK, ENTRY_BLOCK_PTR);
146 SET_BASIC_BLOCK (EXIT_BLOCK, EXIT_BLOCK_PTR);
147 ENTRY_BLOCK_PTR->next_bb = EXIT_BLOCK_PTR;
148 EXIT_BLOCK_PTR->prev_bb = ENTRY_BLOCK_PTR;
151 /*---------------------------------------------------------------------------
153 ---------------------------------------------------------------------------*/
155 /* Entry point to the CFG builder for trees. TP points to the list of
156 statements to be added to the flowgraph. */
159 build_tree_cfg (tree *tp)
161 /* Register specific tree functions. */
162 tree_register_cfg_hooks ();
164 memset ((void *) &cfg_stats, 0, sizeof (cfg_stats));
166 init_empty_tree_cfg ();
168 found_computed_goto = 0;
171 /* Computed gotos are hell to deal with, especially if there are
172 lots of them with a large number of destinations. So we factor
173 them to a common computed goto location before we build the
174 edge list. After we convert back to normal form, we will un-factor
175 the computed gotos since factoring introduces an unwanted jump. */
176 if (found_computed_goto)
177 factor_computed_gotos ();
179 /* Make sure there is always at least one block, even if it's empty. */
180 if (n_basic_blocks == NUM_FIXED_BLOCKS)
181 create_empty_bb (ENTRY_BLOCK_PTR);
183 /* Adjust the size of the array. */
184 if (VEC_length (basic_block, basic_block_info) < (size_t) n_basic_blocks)
186 size_t old_size = VEC_length (basic_block, basic_block_info);
188 VEC_safe_grow (basic_block, gc, basic_block_info, n_basic_blocks);
189 p = VEC_address (basic_block, basic_block_info);
190 memset (&p[old_size], 0,
191 sizeof (basic_block) * (n_basic_blocks - old_size));
194 /* To speed up statement iterator walks, we first purge dead labels. */
195 cleanup_dead_labels ();
197 /* Group case nodes to reduce the number of edges.
198 We do this after cleaning up dead labels because otherwise we miss
199 a lot of obvious case merging opportunities. */
200 group_case_labels ();
202 /* Create the edges of the flowgraph. */
205 /* Debugging dumps. */
207 /* Write the flowgraph to a VCG file. */
209 int local_dump_flags;
210 FILE *vcg_file = dump_begin (TDI_vcg, &local_dump_flags);
213 tree_cfg2vcg (vcg_file);
214 dump_end (TDI_vcg, vcg_file);
218 #ifdef ENABLE_CHECKING
222 /* Dump a textual representation of the flowgraph. */
224 dump_tree_cfg (dump_file, dump_flags);
228 execute_build_cfg (void)
230 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl));
234 struct tree_opt_pass pass_build_cfg =
238 execute_build_cfg, /* execute */
241 0, /* static_pass_number */
242 TV_TREE_CFG, /* tv_id */
243 PROP_gimple_leh, /* properties_required */
244 PROP_cfg, /* properties_provided */
245 0, /* properties_destroyed */
246 0, /* todo_flags_start */
247 TODO_verify_stmts, /* todo_flags_finish */
251 /* Search the CFG for any computed gotos. If found, factor them to a
252 common computed goto site. Also record the location of that site so
253 that we can un-factor the gotos after we have converted back to
257 factor_computed_gotos (void)
260 tree factored_label_decl = NULL;
262 tree factored_computed_goto_label = NULL;
263 tree factored_computed_goto = NULL;
265 /* We know there are one or more computed gotos in this function.
266 Examine the last statement in each basic block to see if the block
267 ends with a computed goto. */
271 block_stmt_iterator bsi = bsi_last (bb);
276 last = bsi_stmt (bsi);
278 /* Ignore the computed goto we create when we factor the original
280 if (last == factored_computed_goto)
283 /* If the last statement is a computed goto, factor it. */
284 if (computed_goto_p (last))
288 /* The first time we find a computed goto we need to create
289 the factored goto block and the variable each original
290 computed goto will use for their goto destination. */
291 if (! factored_computed_goto)
293 basic_block new_bb = create_empty_bb (bb);
294 block_stmt_iterator new_bsi = bsi_start (new_bb);
296 /* Create the destination of the factored goto. Each original
297 computed goto will put its desired destination into this
298 variable and jump to the label we create immediately
300 var = create_tmp_var (ptr_type_node, "gotovar");
302 /* Build a label for the new block which will contain the
303 factored computed goto. */
304 factored_label_decl = create_artificial_label ();
305 factored_computed_goto_label
306 = build1 (LABEL_EXPR, void_type_node, factored_label_decl);
307 bsi_insert_after (&new_bsi, factored_computed_goto_label,
310 /* Build our new computed goto. */
311 factored_computed_goto = build1 (GOTO_EXPR, void_type_node, var);
312 bsi_insert_after (&new_bsi, factored_computed_goto,
316 /* Copy the original computed goto's destination into VAR. */
317 assignment = build2 (MODIFY_EXPR, ptr_type_node,
318 var, GOTO_DESTINATION (last));
319 bsi_insert_before (&bsi, assignment, BSI_SAME_STMT);
321 /* And re-vector the computed goto to the new destination. */
322 GOTO_DESTINATION (last) = factored_label_decl;
328 /* Build a flowgraph for the statement_list STMT_LIST. */
331 make_blocks (tree stmt_list)
333 tree_stmt_iterator i = tsi_start (stmt_list);
335 bool start_new_block = true;
336 bool first_stmt_of_list = true;
337 basic_block bb = ENTRY_BLOCK_PTR;
339 while (!tsi_end_p (i))
346 /* If the statement starts a new basic block or if we have determined
347 in a previous pass that we need to create a new block for STMT, do
349 if (start_new_block || stmt_starts_bb_p (stmt, prev_stmt))
351 if (!first_stmt_of_list)
352 stmt_list = tsi_split_statement_list_before (&i);
353 bb = create_basic_block (stmt_list, NULL, bb);
354 start_new_block = false;
357 /* Now add STMT to BB and create the subgraphs for special statement
359 set_bb_for_stmt (stmt, bb);
361 if (computed_goto_p (stmt))
362 found_computed_goto = true;
364 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
366 if (stmt_ends_bb_p (stmt))
367 start_new_block = true;
370 first_stmt_of_list = false;
375 /* Create and return a new empty basic block after bb AFTER. */
378 create_bb (void *h, void *e, basic_block after)
384 /* Create and initialize a new basic block. Since alloc_block uses
385 ggc_alloc_cleared to allocate a basic block, we do not have to
386 clear the newly allocated basic block here. */
389 bb->index = last_basic_block;
391 bb->stmt_list = h ? (tree) h : alloc_stmt_list ();
393 /* Add the new block to the linked list of blocks. */
394 link_block (bb, after);
396 /* Grow the basic block array if needed. */
397 if ((size_t) last_basic_block == VEC_length (basic_block, basic_block_info))
399 size_t old_size = VEC_length (basic_block, basic_block_info);
400 size_t new_size = last_basic_block + (last_basic_block + 3) / 4;
402 VEC_safe_grow (basic_block, gc, basic_block_info, new_size);
403 p = VEC_address (basic_block, basic_block_info);
404 memset (&p[old_size], 0, sizeof (basic_block) * (new_size - old_size));
407 /* Add the newly created block to the array. */
408 SET_BASIC_BLOCK (last_basic_block, bb);
417 /*---------------------------------------------------------------------------
419 ---------------------------------------------------------------------------*/
421 /* Fold COND_EXPR_COND of each COND_EXPR. */
424 fold_cond_expr_cond (void)
430 tree stmt = last_stmt (bb);
433 && TREE_CODE (stmt) == COND_EXPR)
435 tree cond = fold (COND_EXPR_COND (stmt));
436 if (integer_zerop (cond))
437 COND_EXPR_COND (stmt) = boolean_false_node;
438 else if (integer_onep (cond))
439 COND_EXPR_COND (stmt) = boolean_true_node;
444 /* Join all the blocks in the flowgraph. */
450 struct omp_region *cur_region = NULL;
452 /* Create an edge from entry to the first block with executable
454 make_edge (ENTRY_BLOCK_PTR, BASIC_BLOCK (NUM_FIXED_BLOCKS), EDGE_FALLTHRU);
456 /* Traverse the basic block array placing edges. */
459 tree last = last_stmt (bb);
464 enum tree_code code = TREE_CODE (last);
468 make_goto_expr_edges (bb);
472 make_edge (bb, EXIT_BLOCK_PTR, 0);
476 make_cond_expr_edges (bb);
480 make_switch_expr_edges (bb);
484 make_eh_edges (last);
489 /* If this function receives a nonlocal goto, then we need to
490 make edges from this call site to all the nonlocal goto
492 if (tree_can_make_abnormal_goto (last))
493 make_abnormal_goto_edges (bb, true);
495 /* If this statement has reachable exception handlers, then
496 create abnormal edges to them. */
497 make_eh_edges (last);
499 /* Some calls are known not to return. */
500 fallthru = !(call_expr_flags (last) & ECF_NORETURN);
504 if (is_ctrl_altering_stmt (last))
506 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
507 CALL_EXPR may have an abnormal edge. Search the RHS for
508 this case and create any required edges. */
509 if (tree_can_make_abnormal_goto (last))
510 make_abnormal_goto_edges (bb, true);
512 make_eh_edges (last);
524 cur_region = new_omp_region (bb, code, cur_region);
529 cur_region = new_omp_region (bb, code, cur_region);
534 /* In the case of an OMP_SECTION, the edge will go somewhere
535 other than the next block. This will be created later. */
536 cur_region->exit = bb;
537 fallthru = cur_region->type != OMP_SECTION;
538 cur_region = cur_region->outer;
542 cur_region->cont = bb;
543 switch (cur_region->type)
546 /* ??? Technically there should be a some sort of loopback
547 edge here, but it goes to a block that doesn't exist yet,
548 and without it, updating the ssa form would be a real
549 bear. Fortunately, we don't yet do ssa before expanding
554 /* Wire up the edges into and out of the nested sections. */
555 /* ??? Similarly wrt loopback. */
557 struct omp_region *i;
558 for (i = cur_region->inner; i ; i = i->next)
560 gcc_assert (i->type == OMP_SECTION);
561 make_edge (cur_region->entry, i->entry, 0);
562 make_edge (i->exit, bb, EDGE_FALLTHRU);
574 gcc_assert (!stmt_ends_bb_p (last));
582 make_edge (bb, bb->next_bb, EDGE_FALLTHRU);
588 /* Fold COND_EXPR_COND of each COND_EXPR. */
589 fold_cond_expr_cond ();
591 /* Clean up the graph and warn for unreachable code. */
596 /* Create the edges for a COND_EXPR starting at block BB.
597 At this point, both clauses must contain only simple gotos. */
600 make_cond_expr_edges (basic_block bb)
602 tree entry = last_stmt (bb);
603 basic_block then_bb, else_bb;
604 tree then_label, else_label;
608 gcc_assert (TREE_CODE (entry) == COND_EXPR);
610 /* Entry basic blocks for each component. */
611 then_label = GOTO_DESTINATION (COND_EXPR_THEN (entry));
612 else_label = GOTO_DESTINATION (COND_EXPR_ELSE (entry));
613 then_bb = label_to_block (then_label);
614 else_bb = label_to_block (else_label);
616 e = make_edge (bb, then_bb, EDGE_TRUE_VALUE);
617 #ifdef USE_MAPPED_LOCATION
618 e->goto_locus = EXPR_LOCATION (COND_EXPR_THEN (entry));
620 e->goto_locus = EXPR_LOCUS (COND_EXPR_THEN (entry));
622 e = make_edge (bb, else_bb, EDGE_FALSE_VALUE);
625 #ifdef USE_MAPPED_LOCATION
626 e->goto_locus = EXPR_LOCATION (COND_EXPR_ELSE (entry));
628 e->goto_locus = EXPR_LOCUS (COND_EXPR_ELSE (entry));
633 /* Hashing routine for EDGE_TO_CASES. */
636 edge_to_cases_hash (const void *p)
638 edge e = ((struct edge_to_cases_elt *)p)->e;
640 /* Hash on the edge itself (which is a pointer). */
641 return htab_hash_pointer (e);
644 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
645 for equality is just a pointer comparison. */
648 edge_to_cases_eq (const void *p1, const void *p2)
650 edge e1 = ((struct edge_to_cases_elt *)p1)->e;
651 edge e2 = ((struct edge_to_cases_elt *)p2)->e;
656 /* Called for each element in the hash table (P) as we delete the
657 edge to cases hash table.
659 Clear all the TREE_CHAINs to prevent problems with copying of
660 SWITCH_EXPRs and structure sharing rules, then free the hash table
664 edge_to_cases_cleanup (void *p)
666 struct edge_to_cases_elt *elt = (struct edge_to_cases_elt *) p;
669 for (t = elt->case_labels; t; t = next)
671 next = TREE_CHAIN (t);
672 TREE_CHAIN (t) = NULL;
677 /* Start recording information mapping edges to case labels. */
680 start_recording_case_labels (void)
682 gcc_assert (edge_to_cases == NULL);
684 edge_to_cases = htab_create (37,
687 edge_to_cases_cleanup);
690 /* Return nonzero if we are recording information for case labels. */
693 recording_case_labels_p (void)
695 return (edge_to_cases != NULL);
698 /* Stop recording information mapping edges to case labels and
699 remove any information we have recorded. */
701 end_recording_case_labels (void)
703 htab_delete (edge_to_cases);
704 edge_to_cases = NULL;
707 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
710 record_switch_edge (edge e, tree case_label)
712 struct edge_to_cases_elt *elt;
715 /* Build a hash table element so we can see if E is already
717 elt = XNEW (struct edge_to_cases_elt);
719 elt->case_labels = case_label;
721 slot = htab_find_slot (edge_to_cases, elt, INSERT);
725 /* E was not in the hash table. Install E into the hash table. */
730 /* E was already in the hash table. Free ELT as we do not need it
734 /* Get the entry stored in the hash table. */
735 elt = (struct edge_to_cases_elt *) *slot;
737 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
738 TREE_CHAIN (case_label) = elt->case_labels;
739 elt->case_labels = case_label;
743 /* If we are inside a {start,end}_recording_cases block, then return
744 a chain of CASE_LABEL_EXPRs from T which reference E.
746 Otherwise return NULL. */
749 get_cases_for_edge (edge e, tree t)
751 struct edge_to_cases_elt elt, *elt_p;
756 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
757 chains available. Return NULL so the caller can detect this case. */
758 if (!recording_case_labels_p ())
763 elt.case_labels = NULL;
764 slot = htab_find_slot (edge_to_cases, &elt, NO_INSERT);
768 elt_p = (struct edge_to_cases_elt *)*slot;
769 return elt_p->case_labels;
772 /* If we did not find E in the hash table, then this must be the first
773 time we have been queried for information about E & T. Add all the
774 elements from T to the hash table then perform the query again. */
776 vec = SWITCH_LABELS (t);
777 n = TREE_VEC_LENGTH (vec);
778 for (i = 0; i < n; i++)
780 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
781 basic_block label_bb = label_to_block (lab);
782 record_switch_edge (find_edge (e->src, label_bb), TREE_VEC_ELT (vec, i));
787 /* Create the edges for a SWITCH_EXPR starting at block BB.
788 At this point, the switch body has been lowered and the
789 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
792 make_switch_expr_edges (basic_block bb)
794 tree entry = last_stmt (bb);
798 vec = SWITCH_LABELS (entry);
799 n = TREE_VEC_LENGTH (vec);
801 for (i = 0; i < n; ++i)
803 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
804 basic_block label_bb = label_to_block (lab);
805 make_edge (bb, label_bb, 0);
810 /* Return the basic block holding label DEST. */
813 label_to_block_fn (struct function *ifun, tree dest)
815 int uid = LABEL_DECL_UID (dest);
817 /* We would die hard when faced by an undefined label. Emit a label to
818 the very first basic block. This will hopefully make even the dataflow
819 and undefined variable warnings quite right. */
820 if ((errorcount || sorrycount) && uid < 0)
822 block_stmt_iterator bsi =
823 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS));
826 stmt = build1 (LABEL_EXPR, void_type_node, dest);
827 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
828 uid = LABEL_DECL_UID (dest);
830 if (VEC_length (basic_block, ifun->cfg->x_label_to_block_map)
831 <= (unsigned int) uid)
833 return VEC_index (basic_block, ifun->cfg->x_label_to_block_map, uid);
836 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
837 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
840 make_abnormal_goto_edges (basic_block bb, bool for_call)
842 basic_block target_bb;
843 block_stmt_iterator bsi;
845 FOR_EACH_BB (target_bb)
846 for (bsi = bsi_start (target_bb); !bsi_end_p (bsi); bsi_next (&bsi))
848 tree target = bsi_stmt (bsi);
850 if (TREE_CODE (target) != LABEL_EXPR)
853 target = LABEL_EXPR_LABEL (target);
855 /* Make an edge to every label block that has been marked as a
856 potential target for a computed goto or a non-local goto. */
857 if ((FORCED_LABEL (target) && !for_call)
858 || (DECL_NONLOCAL (target) && for_call))
860 make_edge (bb, target_bb, EDGE_ABNORMAL);
866 /* Create edges for a goto statement at block BB. */
869 make_goto_expr_edges (basic_block bb)
871 block_stmt_iterator last = bsi_last (bb);
872 tree goto_t = bsi_stmt (last);
874 /* A simple GOTO creates normal edges. */
875 if (simple_goto_p (goto_t))
877 tree dest = GOTO_DESTINATION (goto_t);
878 edge e = make_edge (bb, label_to_block (dest), EDGE_FALLTHRU);
879 #ifdef USE_MAPPED_LOCATION
880 e->goto_locus = EXPR_LOCATION (goto_t);
882 e->goto_locus = EXPR_LOCUS (goto_t);
884 bsi_remove (&last, true);
888 /* A computed GOTO creates abnormal edges. */
889 make_abnormal_goto_edges (bb, false);
893 /*---------------------------------------------------------------------------
895 ---------------------------------------------------------------------------*/
897 /* Cleanup useless labels in basic blocks. This is something we wish
898 to do early because it allows us to group case labels before creating
899 the edges for the CFG, and it speeds up block statement iterators in
901 We only run this pass once, running it more than once is probably not
904 /* A map from basic block index to the leading label of that block. */
905 static tree *label_for_bb;
907 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
909 update_eh_label (struct eh_region *region)
911 tree old_label = get_eh_region_tree_label (region);
915 basic_block bb = label_to_block (old_label);
917 /* ??? After optimizing, there may be EH regions with labels
918 that have already been removed from the function body, so
919 there is no basic block for them. */
923 new_label = label_for_bb[bb->index];
924 set_eh_region_tree_label (region, new_label);
928 /* Given LABEL return the first label in the same basic block. */
930 main_block_label (tree label)
932 basic_block bb = label_to_block (label);
934 /* label_to_block possibly inserted undefined label into the chain. */
935 if (!label_for_bb[bb->index])
936 label_for_bb[bb->index] = label;
937 return label_for_bb[bb->index];
940 /* Cleanup redundant labels. This is a three-step process:
941 1) Find the leading label for each block.
942 2) Redirect all references to labels to the leading labels.
943 3) Cleanup all useless labels. */
946 cleanup_dead_labels (void)
949 label_for_bb = XCNEWVEC (tree, last_basic_block);
951 /* Find a suitable label for each block. We use the first user-defined
952 label if there is one, or otherwise just the first label we see. */
955 block_stmt_iterator i;
957 for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
959 tree label, stmt = bsi_stmt (i);
961 if (TREE_CODE (stmt) != LABEL_EXPR)
964 label = LABEL_EXPR_LABEL (stmt);
966 /* If we have not yet seen a label for the current block,
967 remember this one and see if there are more labels. */
968 if (! label_for_bb[bb->index])
970 label_for_bb[bb->index] = label;
974 /* If we did see a label for the current block already, but it
975 is an artificially created label, replace it if the current
976 label is a user defined label. */
977 if (! DECL_ARTIFICIAL (label)
978 && DECL_ARTIFICIAL (label_for_bb[bb->index]))
980 label_for_bb[bb->index] = label;
986 /* Now redirect all jumps/branches to the selected label.
987 First do so for each block ending in a control statement. */
990 tree stmt = last_stmt (bb);
994 switch (TREE_CODE (stmt))
998 tree true_branch, false_branch;
1000 true_branch = COND_EXPR_THEN (stmt);
1001 false_branch = COND_EXPR_ELSE (stmt);
1003 GOTO_DESTINATION (true_branch)
1004 = main_block_label (GOTO_DESTINATION (true_branch));
1005 GOTO_DESTINATION (false_branch)
1006 = main_block_label (GOTO_DESTINATION (false_branch));
1014 tree vec = SWITCH_LABELS (stmt);
1015 size_t n = TREE_VEC_LENGTH (vec);
1017 /* Replace all destination labels. */
1018 for (i = 0; i < n; ++i)
1020 tree elt = TREE_VEC_ELT (vec, i);
1021 tree label = main_block_label (CASE_LABEL (elt));
1022 CASE_LABEL (elt) = label;
1027 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1028 remove them until after we've created the CFG edges. */
1030 if (! computed_goto_p (stmt))
1032 GOTO_DESTINATION (stmt)
1033 = main_block_label (GOTO_DESTINATION (stmt));
1042 for_each_eh_region (update_eh_label);
1044 /* Finally, purge dead labels. All user-defined labels and labels that
1045 can be the target of non-local gotos and labels which have their
1046 address taken are preserved. */
1049 block_stmt_iterator i;
1050 tree label_for_this_bb = label_for_bb[bb->index];
1052 if (! label_for_this_bb)
1055 for (i = bsi_start (bb); !bsi_end_p (i); )
1057 tree label, stmt = bsi_stmt (i);
1059 if (TREE_CODE (stmt) != LABEL_EXPR)
1062 label = LABEL_EXPR_LABEL (stmt);
1064 if (label == label_for_this_bb
1065 || ! DECL_ARTIFICIAL (label)
1066 || DECL_NONLOCAL (label)
1067 || FORCED_LABEL (label))
1070 bsi_remove (&i, true);
1074 free (label_for_bb);
1077 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1078 and scan the sorted vector of cases. Combine the ones jumping to the
1080 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1083 group_case_labels (void)
1089 tree stmt = last_stmt (bb);
1090 if (stmt && TREE_CODE (stmt) == SWITCH_EXPR)
1092 tree labels = SWITCH_LABELS (stmt);
1093 int old_size = TREE_VEC_LENGTH (labels);
1094 int i, j, new_size = old_size;
1095 tree default_case = TREE_VEC_ELT (labels, old_size - 1);
1098 /* The default label is always the last case in a switch
1099 statement after gimplification. */
1100 default_label = CASE_LABEL (default_case);
1102 /* Look for possible opportunities to merge cases.
1103 Ignore the last element of the label vector because it
1104 must be the default case. */
1106 while (i < old_size - 1)
1108 tree base_case, base_label, base_high;
1109 base_case = TREE_VEC_ELT (labels, i);
1111 gcc_assert (base_case);
1112 base_label = CASE_LABEL (base_case);
1114 /* Discard cases that have the same destination as the
1116 if (base_label == default_label)
1118 TREE_VEC_ELT (labels, i) = NULL_TREE;
1124 base_high = CASE_HIGH (base_case) ?
1125 CASE_HIGH (base_case) : CASE_LOW (base_case);
1127 /* Try to merge case labels. Break out when we reach the end
1128 of the label vector or when we cannot merge the next case
1129 label with the current one. */
1130 while (i < old_size - 1)
1132 tree merge_case = TREE_VEC_ELT (labels, i);
1133 tree merge_label = CASE_LABEL (merge_case);
1134 tree t = int_const_binop (PLUS_EXPR, base_high,
1135 integer_one_node, 1);
1137 /* Merge the cases if they jump to the same place,
1138 and their ranges are consecutive. */
1139 if (merge_label == base_label
1140 && tree_int_cst_equal (CASE_LOW (merge_case), t))
1142 base_high = CASE_HIGH (merge_case) ?
1143 CASE_HIGH (merge_case) : CASE_LOW (merge_case);
1144 CASE_HIGH (base_case) = base_high;
1145 TREE_VEC_ELT (labels, i) = NULL_TREE;
1154 /* Compress the case labels in the label vector, and adjust the
1155 length of the vector. */
1156 for (i = 0, j = 0; i < new_size; i++)
1158 while (! TREE_VEC_ELT (labels, j))
1160 TREE_VEC_ELT (labels, i) = TREE_VEC_ELT (labels, j++);
1162 TREE_VEC_LENGTH (labels) = new_size;
1167 /* Checks whether we can merge block B into block A. */
1170 tree_can_merge_blocks_p (basic_block a, basic_block b)
1173 block_stmt_iterator bsi;
1176 if (!single_succ_p (a))
1179 if (single_succ_edge (a)->flags & EDGE_ABNORMAL)
1182 if (single_succ (a) != b)
1185 if (!single_pred_p (b))
1188 if (b == EXIT_BLOCK_PTR)
1191 /* If A ends by a statement causing exceptions or something similar, we
1192 cannot merge the blocks. */
1193 stmt = last_stmt (a);
1194 if (stmt && stmt_ends_bb_p (stmt))
1197 /* Do not allow a block with only a non-local label to be merged. */
1198 if (stmt && TREE_CODE (stmt) == LABEL_EXPR
1199 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
1202 /* It must be possible to eliminate all phi nodes in B. If ssa form
1203 is not up-to-date, we cannot eliminate any phis; however, if only
1204 some symbols as whole are marked for renaming, this is not a problem,
1205 as phi nodes for those symbols are irrelevant in updating anyway. */
1206 phi = phi_nodes (b);
1209 if (name_mappings_registered_p ())
1212 for (; phi; phi = PHI_CHAIN (phi))
1213 if (!is_gimple_reg (PHI_RESULT (phi))
1214 && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
1218 /* Do not remove user labels. */
1219 for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
1221 stmt = bsi_stmt (bsi);
1222 if (TREE_CODE (stmt) != LABEL_EXPR)
1224 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt)))
1228 /* Protect the loop latches. */
1230 && b->loop_father->latch == b)
1236 /* Replaces all uses of NAME by VAL. */
1239 replace_uses_by (tree name, tree val)
1241 imm_use_iterator imm_iter;
1247 FOR_EACH_IMM_USE_STMT (stmt, imm_iter, name)
1249 FOR_EACH_IMM_USE_ON_STMT (use, imm_iter)
1251 replace_exp (use, val);
1253 if (TREE_CODE (stmt) == PHI_NODE)
1255 e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
1256 if (e->flags & EDGE_ABNORMAL)
1258 /* This can only occur for virtual operands, since
1259 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1260 would prevent replacement. */
1261 gcc_assert (!is_gimple_reg (name));
1262 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
1266 if (TREE_CODE (stmt) != PHI_NODE)
1270 fold_stmt_inplace (stmt);
1271 rhs = get_rhs (stmt);
1272 if (TREE_CODE (rhs) == ADDR_EXPR)
1273 recompute_tree_invariant_for_addr_expr (rhs);
1275 maybe_clean_or_replace_eh_stmt (stmt, stmt);
1276 mark_new_vars_to_rename (stmt);
1280 gcc_assert (num_imm_uses (name) == 0);
1282 /* Also update the trees stored in loop structures. */
1287 for (i = 0; i < current_loops->num; i++)
1289 loop = current_loops->parray[i];
1291 substitute_in_loop_info (loop, name, val);
1296 /* Merge block B into block A. */
1299 tree_merge_blocks (basic_block a, basic_block b)
1301 block_stmt_iterator bsi;
1302 tree_stmt_iterator last;
1306 fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
1308 /* Remove all single-valued PHI nodes from block B of the form
1309 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1311 for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
1313 tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
1315 bool may_replace_uses = may_propagate_copy (def, use);
1317 /* In case we have loops to care about, do not propagate arguments of
1318 loop closed ssa phi nodes. */
1320 && is_gimple_reg (def)
1321 && TREE_CODE (use) == SSA_NAME
1322 && a->loop_father != b->loop_father)
1323 may_replace_uses = false;
1325 if (!may_replace_uses)
1327 gcc_assert (is_gimple_reg (def));
1329 /* Note that just emitting the copies is fine -- there is no problem
1330 with ordering of phi nodes. This is because A is the single
1331 predecessor of B, therefore results of the phi nodes cannot
1332 appear as arguments of the phi nodes. */
1333 copy = build2 (MODIFY_EXPR, void_type_node, def, use);
1334 bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
1335 SET_PHI_RESULT (phi, NULL_TREE);
1336 SSA_NAME_DEF_STMT (def) = copy;
1339 replace_uses_by (def, use);
1341 remove_phi_node (phi, NULL);
1344 /* Ensure that B follows A. */
1345 move_block_after (b, a);
1347 gcc_assert (single_succ_edge (a)->flags & EDGE_FALLTHRU);
1348 gcc_assert (!last_stmt (a) || !stmt_ends_bb_p (last_stmt (a)));
1350 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1351 for (bsi = bsi_start (b); !bsi_end_p (bsi);)
1353 if (TREE_CODE (bsi_stmt (bsi)) == LABEL_EXPR)
1355 tree label = bsi_stmt (bsi);
1357 bsi_remove (&bsi, false);
1358 /* Now that we can thread computed gotos, we might have
1359 a situation where we have a forced label in block B
1360 However, the label at the start of block B might still be
1361 used in other ways (think about the runtime checking for
1362 Fortran assigned gotos). So we can not just delete the
1363 label. Instead we move the label to the start of block A. */
1364 if (FORCED_LABEL (LABEL_EXPR_LABEL (label)))
1366 block_stmt_iterator dest_bsi = bsi_start (a);
1367 bsi_insert_before (&dest_bsi, label, BSI_NEW_STMT);
1372 change_bb_for_stmt (bsi_stmt (bsi), a);
1377 /* Merge the chains. */
1378 last = tsi_last (a->stmt_list);
1379 tsi_link_after (&last, b->stmt_list, TSI_NEW_STMT);
1380 b->stmt_list = NULL;
1384 /* Return the one of two successors of BB that is not reachable by a
1385 reached by a complex edge, if there is one. Else, return BB. We use
1386 this in optimizations that use post-dominators for their heuristics,
1387 to catch the cases in C++ where function calls are involved. */
1390 single_noncomplex_succ (basic_block bb)
1393 if (EDGE_COUNT (bb->succs) != 2)
1396 e0 = EDGE_SUCC (bb, 0);
1397 e1 = EDGE_SUCC (bb, 1);
1398 if (e0->flags & EDGE_COMPLEX)
1400 if (e1->flags & EDGE_COMPLEX)
1407 /* Walk the function tree removing unnecessary statements.
1409 * Empty statement nodes are removed
1411 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1413 * Unnecessary COND_EXPRs are removed
1415 * Some unnecessary BIND_EXPRs are removed
1417 Clearly more work could be done. The trick is doing the analysis
1418 and removal fast enough to be a net improvement in compile times.
1420 Note that when we remove a control structure such as a COND_EXPR
1421 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1422 to ensure we eliminate all the useless code. */
1433 static void remove_useless_stmts_1 (tree *, struct rus_data *);
1436 remove_useless_stmts_warn_notreached (tree stmt)
1438 if (EXPR_HAS_LOCATION (stmt))
1440 location_t loc = EXPR_LOCATION (stmt);
1441 if (LOCATION_LINE (loc) > 0)
1443 warning (0, "%Hwill never be executed", &loc);
1448 switch (TREE_CODE (stmt))
1450 case STATEMENT_LIST:
1452 tree_stmt_iterator i;
1453 for (i = tsi_start (stmt); !tsi_end_p (i); tsi_next (&i))
1454 if (remove_useless_stmts_warn_notreached (tsi_stmt (i)))
1460 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt)))
1462 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt)))
1464 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt)))
1468 case TRY_FINALLY_EXPR:
1469 case TRY_CATCH_EXPR:
1470 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 0)))
1472 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt, 1)))
1477 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt));
1478 case EH_FILTER_EXPR:
1479 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt));
1481 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt));
1484 /* Not a live container. */
1492 remove_useless_stmts_cond (tree *stmt_p, struct rus_data *data)
1494 tree then_clause, else_clause, cond;
1495 bool save_has_label, then_has_label, else_has_label;
1497 save_has_label = data->has_label;
1498 data->has_label = false;
1499 data->last_goto = NULL;
1501 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p), data);
1503 then_has_label = data->has_label;
1504 data->has_label = false;
1505 data->last_goto = NULL;
1507 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p), data);
1509 else_has_label = data->has_label;
1510 data->has_label = save_has_label | then_has_label | else_has_label;
1512 then_clause = COND_EXPR_THEN (*stmt_p);
1513 else_clause = COND_EXPR_ELSE (*stmt_p);
1514 cond = fold (COND_EXPR_COND (*stmt_p));
1516 /* If neither arm does anything at all, we can remove the whole IF. */
1517 if (!TREE_SIDE_EFFECTS (then_clause) && !TREE_SIDE_EFFECTS (else_clause))
1519 *stmt_p = build_empty_stmt ();
1520 data->repeat = true;
1523 /* If there are no reachable statements in an arm, then we can
1524 zap the entire conditional. */
1525 else if (integer_nonzerop (cond) && !else_has_label)
1527 if (warn_notreached)
1528 remove_useless_stmts_warn_notreached (else_clause);
1529 *stmt_p = then_clause;
1530 data->repeat = true;
1532 else if (integer_zerop (cond) && !then_has_label)
1534 if (warn_notreached)
1535 remove_useless_stmts_warn_notreached (then_clause);
1536 *stmt_p = else_clause;
1537 data->repeat = true;
1540 /* Check a couple of simple things on then/else with single stmts. */
1543 tree then_stmt = expr_only (then_clause);
1544 tree else_stmt = expr_only (else_clause);
1546 /* Notice branches to a common destination. */
1547 if (then_stmt && else_stmt
1548 && TREE_CODE (then_stmt) == GOTO_EXPR
1549 && TREE_CODE (else_stmt) == GOTO_EXPR
1550 && (GOTO_DESTINATION (then_stmt) == GOTO_DESTINATION (else_stmt)))
1552 *stmt_p = then_stmt;
1553 data->repeat = true;
1556 /* If the THEN/ELSE clause merely assigns a value to a variable or
1557 parameter which is already known to contain that value, then
1558 remove the useless THEN/ELSE clause. */
1559 else if (TREE_CODE (cond) == VAR_DECL || TREE_CODE (cond) == PARM_DECL)
1562 && TREE_CODE (else_stmt) == MODIFY_EXPR
1563 && TREE_OPERAND (else_stmt, 0) == cond
1564 && integer_zerop (TREE_OPERAND (else_stmt, 1)))
1565 COND_EXPR_ELSE (*stmt_p) = alloc_stmt_list ();
1567 else if ((TREE_CODE (cond) == EQ_EXPR || TREE_CODE (cond) == NE_EXPR)
1568 && (TREE_CODE (TREE_OPERAND (cond, 0)) == VAR_DECL
1569 || TREE_CODE (TREE_OPERAND (cond, 0)) == PARM_DECL)
1570 && TREE_CONSTANT (TREE_OPERAND (cond, 1)))
1572 tree stmt = (TREE_CODE (cond) == EQ_EXPR
1573 ? then_stmt : else_stmt);
1574 tree *location = (TREE_CODE (cond) == EQ_EXPR
1575 ? &COND_EXPR_THEN (*stmt_p)
1576 : &COND_EXPR_ELSE (*stmt_p));
1579 && TREE_CODE (stmt) == MODIFY_EXPR
1580 && TREE_OPERAND (stmt, 0) == TREE_OPERAND (cond, 0)
1581 && TREE_OPERAND (stmt, 1) == TREE_OPERAND (cond, 1))
1582 *location = alloc_stmt_list ();
1586 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1587 would be re-introduced during lowering. */
1588 data->last_goto = NULL;
1593 remove_useless_stmts_tf (tree *stmt_p, struct rus_data *data)
1595 bool save_may_branch, save_may_throw;
1596 bool this_may_branch, this_may_throw;
1598 /* Collect may_branch and may_throw information for the body only. */
1599 save_may_branch = data->may_branch;
1600 save_may_throw = data->may_throw;
1601 data->may_branch = false;
1602 data->may_throw = false;
1603 data->last_goto = NULL;
1605 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1607 this_may_branch = data->may_branch;
1608 this_may_throw = data->may_throw;
1609 data->may_branch |= save_may_branch;
1610 data->may_throw |= save_may_throw;
1611 data->last_goto = NULL;
1613 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1615 /* If the body is empty, then we can emit the FINALLY block without
1616 the enclosing TRY_FINALLY_EXPR. */
1617 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 0)))
1619 *stmt_p = TREE_OPERAND (*stmt_p, 1);
1620 data->repeat = true;
1623 /* If the handler is empty, then we can emit the TRY block without
1624 the enclosing TRY_FINALLY_EXPR. */
1625 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1627 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1628 data->repeat = true;
1631 /* If the body neither throws, nor branches, then we can safely
1632 string the TRY and FINALLY blocks together. */
1633 else if (!this_may_branch && !this_may_throw)
1635 tree stmt = *stmt_p;
1636 *stmt_p = TREE_OPERAND (stmt, 0);
1637 append_to_statement_list (TREE_OPERAND (stmt, 1), stmt_p);
1638 data->repeat = true;
1644 remove_useless_stmts_tc (tree *stmt_p, struct rus_data *data)
1646 bool save_may_throw, this_may_throw;
1647 tree_stmt_iterator i;
1650 /* Collect may_throw information for the body only. */
1651 save_may_throw = data->may_throw;
1652 data->may_throw = false;
1653 data->last_goto = NULL;
1655 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 0), data);
1657 this_may_throw = data->may_throw;
1658 data->may_throw = save_may_throw;
1660 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1661 if (!this_may_throw)
1663 if (warn_notreached)
1664 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p, 1));
1665 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1666 data->repeat = true;
1670 /* Process the catch clause specially. We may be able to tell that
1671 no exceptions propagate past this point. */
1673 this_may_throw = true;
1674 i = tsi_start (TREE_OPERAND (*stmt_p, 1));
1675 stmt = tsi_stmt (i);
1676 data->last_goto = NULL;
1678 switch (TREE_CODE (stmt))
1681 for (; !tsi_end_p (i); tsi_next (&i))
1683 stmt = tsi_stmt (i);
1684 /* If we catch all exceptions, then the body does not
1685 propagate exceptions past this point. */
1686 if (CATCH_TYPES (stmt) == NULL)
1687 this_may_throw = false;
1688 data->last_goto = NULL;
1689 remove_useless_stmts_1 (&CATCH_BODY (stmt), data);
1693 case EH_FILTER_EXPR:
1694 if (EH_FILTER_MUST_NOT_THROW (stmt))
1695 this_may_throw = false;
1696 else if (EH_FILTER_TYPES (stmt) == NULL)
1697 this_may_throw = false;
1698 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt), data);
1702 /* Otherwise this is a cleanup. */
1703 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p, 1), data);
1705 /* If the cleanup is empty, then we can emit the TRY block without
1706 the enclosing TRY_CATCH_EXPR. */
1707 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p, 1)))
1709 *stmt_p = TREE_OPERAND (*stmt_p, 0);
1710 data->repeat = true;
1714 data->may_throw |= this_may_throw;
1719 remove_useless_stmts_bind (tree *stmt_p, struct rus_data *data)
1723 /* First remove anything underneath the BIND_EXPR. */
1724 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p), data);
1726 /* If the BIND_EXPR has no variables, then we can pull everything
1727 up one level and remove the BIND_EXPR, unless this is the toplevel
1728 BIND_EXPR for the current function or an inlined function.
1730 When this situation occurs we will want to apply this
1731 optimization again. */
1732 block = BIND_EXPR_BLOCK (*stmt_p);
1733 if (BIND_EXPR_VARS (*stmt_p) == NULL_TREE
1734 && *stmt_p != DECL_SAVED_TREE (current_function_decl)
1736 || ! BLOCK_ABSTRACT_ORIGIN (block)
1737 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block))
1740 *stmt_p = BIND_EXPR_BODY (*stmt_p);
1741 data->repeat = true;
1747 remove_useless_stmts_goto (tree *stmt_p, struct rus_data *data)
1749 tree dest = GOTO_DESTINATION (*stmt_p);
1751 data->may_branch = true;
1752 data->last_goto = NULL;
1754 /* Record the last goto expr, so that we can delete it if unnecessary. */
1755 if (TREE_CODE (dest) == LABEL_DECL)
1756 data->last_goto = stmt_p;
1761 remove_useless_stmts_label (tree *stmt_p, struct rus_data *data)
1763 tree label = LABEL_EXPR_LABEL (*stmt_p);
1765 data->has_label = true;
1767 /* We do want to jump across non-local label receiver code. */
1768 if (DECL_NONLOCAL (label))
1769 data->last_goto = NULL;
1771 else if (data->last_goto && GOTO_DESTINATION (*data->last_goto) == label)
1773 *data->last_goto = build_empty_stmt ();
1774 data->repeat = true;
1777 /* ??? Add something here to delete unused labels. */
1781 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1782 decl. This allows us to eliminate redundant or useless
1783 calls to "const" functions.
1785 Gimplifier already does the same operation, but we may notice functions
1786 being const and pure once their calls has been gimplified, so we need
1787 to update the flag. */
1790 update_call_expr_flags (tree call)
1792 tree decl = get_callee_fndecl (call);
1795 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1796 TREE_SIDE_EFFECTS (call) = 0;
1797 if (TREE_NOTHROW (decl))
1798 TREE_NOTHROW (call) = 1;
1802 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1805 notice_special_calls (tree t)
1807 int flags = call_expr_flags (t);
1809 if (flags & ECF_MAY_BE_ALLOCA)
1810 current_function_calls_alloca = true;
1811 if (flags & ECF_RETURNS_TWICE)
1812 current_function_calls_setjmp = true;
1816 /* Clear flags set by notice_special_calls. Used by dead code removal
1817 to update the flags. */
1820 clear_special_calls (void)
1822 current_function_calls_alloca = false;
1823 current_function_calls_setjmp = false;
1828 remove_useless_stmts_1 (tree *tp, struct rus_data *data)
1832 switch (TREE_CODE (t))
1835 remove_useless_stmts_cond (tp, data);
1838 case TRY_FINALLY_EXPR:
1839 remove_useless_stmts_tf (tp, data);
1842 case TRY_CATCH_EXPR:
1843 remove_useless_stmts_tc (tp, data);
1847 remove_useless_stmts_bind (tp, data);
1851 remove_useless_stmts_goto (tp, data);
1855 remove_useless_stmts_label (tp, data);
1860 data->last_goto = NULL;
1861 data->may_branch = true;
1866 data->last_goto = NULL;
1867 notice_special_calls (t);
1868 update_call_expr_flags (t);
1869 if (tree_could_throw_p (t))
1870 data->may_throw = true;
1874 data->last_goto = NULL;
1876 op = get_call_expr_in (t);
1879 update_call_expr_flags (op);
1880 notice_special_calls (op);
1882 if (tree_could_throw_p (t))
1883 data->may_throw = true;
1886 case STATEMENT_LIST:
1888 tree_stmt_iterator i = tsi_start (t);
1889 while (!tsi_end_p (i))
1892 if (IS_EMPTY_STMT (t))
1898 remove_useless_stmts_1 (tsi_stmt_ptr (i), data);
1901 if (TREE_CODE (t) == STATEMENT_LIST)
1903 tsi_link_before (&i, t, TSI_SAME_STMT);
1913 data->last_goto = NULL;
1917 data->last_goto = NULL;
1923 remove_useless_stmts (void)
1925 struct rus_data data;
1927 clear_special_calls ();
1931 memset (&data, 0, sizeof (data));
1932 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl), &data);
1934 while (data.repeat);
1939 struct tree_opt_pass pass_remove_useless_stmts =
1941 "useless", /* name */
1943 remove_useless_stmts, /* execute */
1946 0, /* static_pass_number */
1948 PROP_gimple_any, /* properties_required */
1949 0, /* properties_provided */
1950 0, /* properties_destroyed */
1951 0, /* todo_flags_start */
1952 TODO_dump_func, /* todo_flags_finish */
1956 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1959 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb)
1963 /* Since this block is no longer reachable, we can just delete all
1964 of its PHI nodes. */
1965 phi = phi_nodes (bb);
1968 tree next = PHI_CHAIN (phi);
1969 remove_phi_node (phi, NULL_TREE);
1973 /* Remove edges to BB's successors. */
1974 while (EDGE_COUNT (bb->succs) > 0)
1975 remove_edge (EDGE_SUCC (bb, 0));
1979 /* Remove statements of basic block BB. */
1982 remove_bb (basic_block bb)
1984 block_stmt_iterator i;
1985 #ifdef USE_MAPPED_LOCATION
1986 source_location loc = UNKNOWN_LOCATION;
1988 source_locus loc = 0;
1993 fprintf (dump_file, "Removing basic block %d\n", bb->index);
1994 if (dump_flags & TDF_DETAILS)
1996 dump_bb (bb, dump_file, 0);
1997 fprintf (dump_file, "\n");
2001 /* If we remove the header or the latch of a loop, mark the loop for
2002 removal by setting its header and latch to NULL. */
2005 struct loop *loop = bb->loop_father;
2007 if (loop->latch == bb
2008 || loop->header == bb)
2011 loop->header = NULL;
2013 /* Also clean up the information associated with the loop. Updating
2014 it would waste time. More importantly, it may refer to ssa
2015 names that were defined in other removed basic block -- these
2016 ssa names are now removed and invalid. */
2017 free_numbers_of_iterations_estimates_loop (loop);
2021 /* Remove all the instructions in the block. */
2022 for (i = bsi_start (bb); !bsi_end_p (i);)
2024 tree stmt = bsi_stmt (i);
2025 if (TREE_CODE (stmt) == LABEL_EXPR
2026 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt))
2027 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))))
2030 block_stmt_iterator new_bsi;
2032 /* A non-reachable non-local label may still be referenced.
2033 But it no longer needs to carry the extra semantics of
2035 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
2037 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)) = 0;
2038 FORCED_LABEL (LABEL_EXPR_LABEL (stmt)) = 1;
2041 new_bb = bb->prev_bb;
2042 new_bsi = bsi_start (new_bb);
2043 bsi_remove (&i, false);
2044 bsi_insert_before (&new_bsi, stmt, BSI_NEW_STMT);
2048 /* Release SSA definitions if we are in SSA. Note that we
2049 may be called when not in SSA. For example,
2050 final_cleanup calls this function via
2051 cleanup_tree_cfg. */
2053 release_defs (stmt);
2055 bsi_remove (&i, true);
2058 /* Don't warn for removed gotos. Gotos are often removed due to
2059 jump threading, thus resulting in bogus warnings. Not great,
2060 since this way we lose warnings for gotos in the original
2061 program that are indeed unreachable. */
2062 if (TREE_CODE (stmt) != GOTO_EXPR && EXPR_HAS_LOCATION (stmt) && !loc)
2064 #ifdef USE_MAPPED_LOCATION
2065 if (EXPR_HAS_LOCATION (stmt))
2066 loc = EXPR_LOCATION (stmt);
2069 t = EXPR_LOCUS (stmt);
2070 if (t && LOCATION_LINE (*t) > 0)
2076 /* If requested, give a warning that the first statement in the
2077 block is unreachable. We walk statements backwards in the
2078 loop above, so the last statement we process is the first statement
2080 #ifdef USE_MAPPED_LOCATION
2081 if (loc > BUILTINS_LOCATION)
2082 warning (OPT_Wunreachable_code, "%Hwill never be executed", &loc);
2085 warning (OPT_Wunreachable_code, "%Hwill never be executed", loc);
2088 remove_phi_nodes_and_edges_for_unreachable_block (bb);
2092 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2093 predicate VAL, return the edge that will be taken out of the block.
2094 If VAL does not match a unique edge, NULL is returned. */
2097 find_taken_edge (basic_block bb, tree val)
2101 stmt = last_stmt (bb);
2104 gcc_assert (is_ctrl_stmt (stmt));
2107 if (! is_gimple_min_invariant (val))
2110 if (TREE_CODE (stmt) == COND_EXPR)
2111 return find_taken_edge_cond_expr (bb, val);
2113 if (TREE_CODE (stmt) == SWITCH_EXPR)
2114 return find_taken_edge_switch_expr (bb, val);
2116 if (computed_goto_p (stmt))
2117 return find_taken_edge_computed_goto (bb, TREE_OPERAND( val, 0));
2122 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2123 statement, determine which of the outgoing edges will be taken out of the
2124 block. Return NULL if either edge may be taken. */
2127 find_taken_edge_computed_goto (basic_block bb, tree val)
2132 dest = label_to_block (val);
2135 e = find_edge (bb, dest);
2136 gcc_assert (e != NULL);
2142 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2143 statement, determine which of the two edges will be taken out of the
2144 block. Return NULL if either edge may be taken. */
2147 find_taken_edge_cond_expr (basic_block bb, tree val)
2149 edge true_edge, false_edge;
2151 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
2153 gcc_assert (TREE_CODE (val) == INTEGER_CST);
2154 return (zero_p (val) ? false_edge : true_edge);
2157 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2158 statement, determine which edge will be taken out of the block. Return
2159 NULL if any edge may be taken. */
2162 find_taken_edge_switch_expr (basic_block bb, tree val)
2164 tree switch_expr, taken_case;
2165 basic_block dest_bb;
2168 switch_expr = last_stmt (bb);
2169 taken_case = find_case_label_for_value (switch_expr, val);
2170 dest_bb = label_to_block (CASE_LABEL (taken_case));
2172 e = find_edge (bb, dest_bb);
2178 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2179 We can make optimal use here of the fact that the case labels are
2180 sorted: We can do a binary search for a case matching VAL. */
2183 find_case_label_for_value (tree switch_expr, tree val)
2185 tree vec = SWITCH_LABELS (switch_expr);
2186 size_t low, high, n = TREE_VEC_LENGTH (vec);
2187 tree default_case = TREE_VEC_ELT (vec, n - 1);
2189 for (low = -1, high = n - 1; high - low > 1; )
2191 size_t i = (high + low) / 2;
2192 tree t = TREE_VEC_ELT (vec, i);
2195 /* Cache the result of comparing CASE_LOW and val. */
2196 cmp = tree_int_cst_compare (CASE_LOW (t), val);
2203 if (CASE_HIGH (t) == NULL)
2205 /* A singe-valued case label. */
2211 /* A case range. We can only handle integer ranges. */
2212 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
2217 return default_case;
2223 /*---------------------------------------------------------------------------
2225 ---------------------------------------------------------------------------*/
2227 /* Dump tree-specific information of block BB to file OUTF. */
2230 tree_dump_bb (basic_block bb, FILE *outf, int indent)
2232 dump_generic_bb (outf, bb, indent, TDF_VOPS);
2236 /* Dump a basic block on stderr. */
2239 debug_tree_bb (basic_block bb)
2241 dump_bb (bb, stderr, 0);
2245 /* Dump basic block with index N on stderr. */
2248 debug_tree_bb_n (int n)
2250 debug_tree_bb (BASIC_BLOCK (n));
2251 return BASIC_BLOCK (n);
2255 /* Dump the CFG on stderr.
2257 FLAGS are the same used by the tree dumping functions
2258 (see TDF_* in tree-pass.h). */
2261 debug_tree_cfg (int flags)
2263 dump_tree_cfg (stderr, flags);
2267 /* Dump the program showing basic block boundaries on the given FILE.
2269 FLAGS are the same used by the tree dumping functions (see TDF_* in
2273 dump_tree_cfg (FILE *file, int flags)
2275 if (flags & TDF_DETAILS)
2277 const char *funcname
2278 = lang_hooks.decl_printable_name (current_function_decl, 2);
2281 fprintf (file, ";; Function %s\n\n", funcname);
2282 fprintf (file, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2283 n_basic_blocks, n_edges, last_basic_block);
2285 brief_dump_cfg (file);
2286 fprintf (file, "\n");
2289 if (flags & TDF_STATS)
2290 dump_cfg_stats (file);
2292 dump_function_to_file (current_function_decl, file, flags | TDF_BLOCKS);
2296 /* Dump CFG statistics on FILE. */
2299 dump_cfg_stats (FILE *file)
2301 static long max_num_merged_labels = 0;
2302 unsigned long size, total = 0;
2305 const char * const fmt_str = "%-30s%-13s%12s\n";
2306 const char * const fmt_str_1 = "%-30s%13d%11lu%c\n";
2307 const char * const fmt_str_2 = "%-30s%13ld%11lu%c\n";
2308 const char * const fmt_str_3 = "%-43s%11lu%c\n";
2309 const char *funcname
2310 = lang_hooks.decl_printable_name (current_function_decl, 2);
2313 fprintf (file, "\nCFG Statistics for %s\n\n", funcname);
2315 fprintf (file, "---------------------------------------------------------\n");
2316 fprintf (file, fmt_str, "", " Number of ", "Memory");
2317 fprintf (file, fmt_str, "", " instances ", "used ");
2318 fprintf (file, "---------------------------------------------------------\n");
2320 size = n_basic_blocks * sizeof (struct basic_block_def);
2322 fprintf (file, fmt_str_1, "Basic blocks", n_basic_blocks,
2323 SCALE (size), LABEL (size));
2327 num_edges += EDGE_COUNT (bb->succs);
2328 size = num_edges * sizeof (struct edge_def);
2330 fprintf (file, fmt_str_2, "Edges", num_edges, SCALE (size), LABEL (size));
2332 fprintf (file, "---------------------------------------------------------\n");
2333 fprintf (file, fmt_str_3, "Total memory used by CFG data", SCALE (total),
2335 fprintf (file, "---------------------------------------------------------\n");
2336 fprintf (file, "\n");
2338 if (cfg_stats.num_merged_labels > max_num_merged_labels)
2339 max_num_merged_labels = cfg_stats.num_merged_labels;
2341 fprintf (file, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2342 cfg_stats.num_merged_labels, max_num_merged_labels);
2344 fprintf (file, "\n");
2348 /* Dump CFG statistics on stderr. Keep extern so that it's always
2349 linked in the final executable. */
2352 debug_cfg_stats (void)
2354 dump_cfg_stats (stderr);
2358 /* Dump the flowgraph to a .vcg FILE. */
2361 tree_cfg2vcg (FILE *file)
2366 const char *funcname
2367 = lang_hooks.decl_printable_name (current_function_decl, 2);
2369 /* Write the file header. */
2370 fprintf (file, "graph: { title: \"%s\"\n", funcname);
2371 fprintf (file, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2372 fprintf (file, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2374 /* Write blocks and edges. */
2375 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2377 fprintf (file, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2380 if (e->flags & EDGE_FAKE)
2381 fprintf (file, " linestyle: dotted priority: 10");
2383 fprintf (file, " linestyle: solid priority: 100");
2385 fprintf (file, " }\n");
2391 enum tree_code head_code, end_code;
2392 const char *head_name, *end_name;
2395 tree first = first_stmt (bb);
2396 tree last = last_stmt (bb);
2400 head_code = TREE_CODE (first);
2401 head_name = tree_code_name[head_code];
2402 head_line = get_lineno (first);
2405 head_name = "no-statement";
2409 end_code = TREE_CODE (last);
2410 end_name = tree_code_name[end_code];
2411 end_line = get_lineno (last);
2414 end_name = "no-statement";
2416 fprintf (file, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2417 bb->index, bb->index, head_name, head_line, end_name,
2420 FOR_EACH_EDGE (e, ei, bb->succs)
2422 if (e->dest == EXIT_BLOCK_PTR)
2423 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb->index);
2425 fprintf (file, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb->index, e->dest->index);
2427 if (e->flags & EDGE_FAKE)
2428 fprintf (file, " priority: 10 linestyle: dotted");
2430 fprintf (file, " priority: 100 linestyle: solid");
2432 fprintf (file, " }\n");
2435 if (bb->next_bb != EXIT_BLOCK_PTR)
2439 fputs ("}\n\n", file);
2444 /*---------------------------------------------------------------------------
2445 Miscellaneous helpers
2446 ---------------------------------------------------------------------------*/
2448 /* Return true if T represents a stmt that always transfers control. */
2451 is_ctrl_stmt (tree t)
2453 return (TREE_CODE (t) == COND_EXPR
2454 || TREE_CODE (t) == SWITCH_EXPR
2455 || TREE_CODE (t) == GOTO_EXPR
2456 || TREE_CODE (t) == RETURN_EXPR
2457 || TREE_CODE (t) == RESX_EXPR);
2461 /* Return true if T is a statement that may alter the flow of control
2462 (e.g., a call to a non-returning function). */
2465 is_ctrl_altering_stmt (tree t)
2470 call = get_call_expr_in (t);
2473 /* A non-pure/const CALL_EXPR alters flow control if the current
2474 function has nonlocal labels. */
2475 if (TREE_SIDE_EFFECTS (call) && current_function_has_nonlocal_label)
2478 /* A CALL_EXPR also alters control flow if it does not return. */
2479 if (call_expr_flags (call) & ECF_NORETURN)
2483 /* OpenMP directives alter control flow. */
2484 if (OMP_DIRECTIVE_P (t))
2487 /* If a statement can throw, it alters control flow. */
2488 return tree_can_throw_internal (t);
2492 /* Return true if T is a computed goto. */
2495 computed_goto_p (tree t)
2497 return (TREE_CODE (t) == GOTO_EXPR
2498 && TREE_CODE (GOTO_DESTINATION (t)) != LABEL_DECL);
2502 /* Return true if T is a simple local goto. */
2505 simple_goto_p (tree t)
2507 return (TREE_CODE (t) == GOTO_EXPR
2508 && TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL);
2512 /* Return true if T can make an abnormal transfer of control flow.
2513 Transfers of control flow associated with EH are excluded. */
2516 tree_can_make_abnormal_goto (tree t)
2518 if (computed_goto_p (t))
2520 if (TREE_CODE (t) == MODIFY_EXPR)
2521 t = TREE_OPERAND (t, 1);
2522 if (TREE_CODE (t) == WITH_SIZE_EXPR)
2523 t = TREE_OPERAND (t, 0);
2524 if (TREE_CODE (t) == CALL_EXPR)
2525 return TREE_SIDE_EFFECTS (t) && current_function_has_nonlocal_label;
2530 /* Return true if T should start a new basic block. PREV_T is the
2531 statement preceding T. It is used when T is a label or a case label.
2532 Labels should only start a new basic block if their previous statement
2533 wasn't a label. Otherwise, sequence of labels would generate
2534 unnecessary basic blocks that only contain a single label. */
2537 stmt_starts_bb_p (tree t, tree prev_t)
2542 /* LABEL_EXPRs start a new basic block only if the preceding
2543 statement wasn't a label of the same type. This prevents the
2544 creation of consecutive blocks that have nothing but a single
2546 if (TREE_CODE (t) == LABEL_EXPR)
2548 /* Nonlocal and computed GOTO targets always start a new block. */
2549 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t))
2550 || FORCED_LABEL (LABEL_EXPR_LABEL (t)))
2553 if (prev_t && TREE_CODE (prev_t) == LABEL_EXPR)
2555 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t)))
2558 cfg_stats.num_merged_labels++;
2569 /* Return true if T should end a basic block. */
2572 stmt_ends_bb_p (tree t)
2574 return is_ctrl_stmt (t) || is_ctrl_altering_stmt (t);
2578 /* Add gotos that used to be represented implicitly in the CFG. */
2581 disband_implicit_edges (void)
2584 block_stmt_iterator last;
2591 last = bsi_last (bb);
2592 stmt = last_stmt (bb);
2594 if (stmt && TREE_CODE (stmt) == COND_EXPR)
2596 /* Remove superfluous gotos from COND_EXPR branches. Moved
2597 from cfg_remove_useless_stmts here since it violates the
2598 invariants for tree--cfg correspondence and thus fits better
2599 here where we do it anyway. */
2600 e = find_edge (bb, bb->next_bb);
2603 if (e->flags & EDGE_TRUE_VALUE)
2604 COND_EXPR_THEN (stmt) = build_empty_stmt ();
2605 else if (e->flags & EDGE_FALSE_VALUE)
2606 COND_EXPR_ELSE (stmt) = build_empty_stmt ();
2609 e->flags |= EDGE_FALLTHRU;
2615 if (stmt && TREE_CODE (stmt) == RETURN_EXPR)
2617 /* Remove the RETURN_EXPR if we may fall though to the exit
2619 gcc_assert (single_succ_p (bb));
2620 gcc_assert (single_succ (bb) == EXIT_BLOCK_PTR);
2622 if (bb->next_bb == EXIT_BLOCK_PTR
2623 && !TREE_OPERAND (stmt, 0))
2625 bsi_remove (&last, true);
2626 single_succ_edge (bb)->flags |= EDGE_FALLTHRU;
2631 /* There can be no fallthru edge if the last statement is a control
2633 if (stmt && is_ctrl_stmt (stmt))
2636 /* Find a fallthru edge and emit the goto if necessary. */
2637 FOR_EACH_EDGE (e, ei, bb->succs)
2638 if (e->flags & EDGE_FALLTHRU)
2641 if (!e || e->dest == bb->next_bb)
2644 gcc_assert (e->dest != EXIT_BLOCK_PTR);
2645 label = tree_block_label (e->dest);
2647 stmt = build1 (GOTO_EXPR, void_type_node, label);
2648 #ifdef USE_MAPPED_LOCATION
2649 SET_EXPR_LOCATION (stmt, e->goto_locus);
2651 SET_EXPR_LOCUS (stmt, e->goto_locus);
2653 bsi_insert_after (&last, stmt, BSI_NEW_STMT);
2654 e->flags &= ~EDGE_FALLTHRU;
2658 /* Remove block annotations and other datastructures. */
2661 delete_tree_cfg_annotations (void)
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 a pointer to the last statement in block BB. */
2690 last_stmt_ptr (basic_block bb)
2692 block_stmt_iterator last = bsi_last (bb);
2693 return !bsi_end_p (last) ? bsi_stmt_ptr (last) : NULL;
2697 /* Return the last statement of an otherwise empty block. Return NULL
2698 if the block is totally empty, or if it contains more than one
2702 last_and_only_stmt (basic_block bb)
2704 block_stmt_iterator i = bsi_last (bb);
2710 last = bsi_stmt (i);
2715 /* Empty statements should no longer appear in the instruction stream.
2716 Everything that might have appeared before should be deleted by
2717 remove_useless_stmts, and the optimizers should just bsi_remove
2718 instead of smashing with build_empty_stmt.
2720 Thus the only thing that should appear here in a block containing
2721 one executable statement is a label. */
2722 prev = bsi_stmt (i);
2723 if (TREE_CODE (prev) == LABEL_EXPR)
2730 /* Mark BB as the basic block holding statement T. */
2733 set_bb_for_stmt (tree t, basic_block bb)
2735 if (TREE_CODE (t) == PHI_NODE)
2737 else if (TREE_CODE (t) == STATEMENT_LIST)
2739 tree_stmt_iterator i;
2740 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2741 set_bb_for_stmt (tsi_stmt (i), bb);
2745 stmt_ann_t ann = get_stmt_ann (t);
2748 /* If the statement is a label, add the label to block-to-labels map
2749 so that we can speed up edge creation for GOTO_EXPRs. */
2750 if (TREE_CODE (t) == LABEL_EXPR)
2754 t = LABEL_EXPR_LABEL (t);
2755 uid = LABEL_DECL_UID (t);
2758 unsigned old_len = VEC_length (basic_block, label_to_block_map);
2759 LABEL_DECL_UID (t) = uid = cfun->last_label_uid++;
2760 if (old_len <= (unsigned) uid)
2763 unsigned new_len = 3 * uid / 2;
2765 VEC_safe_grow (basic_block, gc, label_to_block_map,
2767 addr = VEC_address (basic_block, label_to_block_map);
2768 memset (&addr[old_len],
2769 0, sizeof (basic_block) * (new_len - old_len));
2773 /* We're moving an existing label. Make sure that we've
2774 removed it from the old block. */
2776 || !VEC_index (basic_block, label_to_block_map, uid));
2777 VEC_replace (basic_block, label_to_block_map, uid, bb);
2782 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2783 from one basic block to another.
2784 For BB splitting we can run into quadratic case, so performance is quite
2785 important and knowing that the tables are big enough, change_bb_for_stmt
2786 can inline as leaf function. */
2788 change_bb_for_stmt (tree t, basic_block bb)
2790 get_stmt_ann (t)->bb = bb;
2791 if (TREE_CODE (t) == LABEL_EXPR)
2792 VEC_replace (basic_block, label_to_block_map,
2793 LABEL_DECL_UID (LABEL_EXPR_LABEL (t)), bb);
2796 /* Finds iterator for STMT. */
2798 extern block_stmt_iterator
2799 bsi_for_stmt (tree stmt)
2801 block_stmt_iterator bsi;
2803 for (bsi = bsi_start (bb_for_stmt (stmt)); !bsi_end_p (bsi); bsi_next (&bsi))
2804 if (bsi_stmt (bsi) == stmt)
2810 /* Mark statement T as modified, and update it. */
2812 update_modified_stmts (tree t)
2814 if (TREE_CODE (t) == STATEMENT_LIST)
2816 tree_stmt_iterator i;
2818 for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i))
2820 stmt = tsi_stmt (i);
2821 update_stmt_if_modified (stmt);
2825 update_stmt_if_modified (t);
2828 /* Insert statement (or statement list) T before the statement
2829 pointed-to by iterator I. M specifies how to update iterator I
2830 after insertion (see enum bsi_iterator_update). */
2833 bsi_insert_before (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2835 set_bb_for_stmt (t, i->bb);
2836 update_modified_stmts (t);
2837 tsi_link_before (&i->tsi, t, m);
2841 /* Insert statement (or statement list) T after the statement
2842 pointed-to by iterator I. M specifies how to update iterator I
2843 after insertion (see enum bsi_iterator_update). */
2846 bsi_insert_after (block_stmt_iterator *i, tree t, enum bsi_iterator_update m)
2848 set_bb_for_stmt (t, i->bb);
2849 update_modified_stmts (t);
2850 tsi_link_after (&i->tsi, t, m);
2854 /* Remove the statement pointed to by iterator I. The iterator is updated
2855 to the next statement.
2857 When REMOVE_EH_INFO is true we remove the statement pointed to by
2858 iterator I from the EH tables. Otherwise we do not modify the EH
2861 Generally, REMOVE_EH_INFO should be true when the statement is going to
2862 be removed from the IL and not reinserted elsewhere. */
2865 bsi_remove (block_stmt_iterator *i, bool remove_eh_info)
2867 tree t = bsi_stmt (*i);
2868 set_bb_for_stmt (t, NULL);
2869 delink_stmt_imm_use (t);
2870 tsi_delink (&i->tsi);
2871 mark_stmt_modified (t);
2873 remove_stmt_from_eh_region (t);
2877 /* Move the statement at FROM so it comes right after the statement at TO. */
2880 bsi_move_after (block_stmt_iterator *from, block_stmt_iterator *to)
2882 tree stmt = bsi_stmt (*from);
2883 bsi_remove (from, false);
2884 bsi_insert_after (to, stmt, BSI_SAME_STMT);
2888 /* Move the statement at FROM so it comes right before the statement at TO. */
2891 bsi_move_before (block_stmt_iterator *from, block_stmt_iterator *to)
2893 tree stmt = bsi_stmt (*from);
2894 bsi_remove (from, false);
2895 bsi_insert_before (to, stmt, BSI_SAME_STMT);
2899 /* Move the statement at FROM to the end of basic block BB. */
2902 bsi_move_to_bb_end (block_stmt_iterator *from, basic_block bb)
2904 block_stmt_iterator last = bsi_last (bb);
2906 /* Have to check bsi_end_p because it could be an empty block. */
2907 if (!bsi_end_p (last) && is_ctrl_stmt (bsi_stmt (last)))
2908 bsi_move_before (from, &last);
2910 bsi_move_after (from, &last);
2914 /* Replace the contents of the statement pointed to by iterator BSI
2915 with STMT. If UPDATE_EH_INFO is true, the exception handling
2916 information of the original statement is moved to the new statement. */
2919 bsi_replace (const block_stmt_iterator *bsi, tree stmt, bool update_eh_info)
2922 tree orig_stmt = bsi_stmt (*bsi);
2924 SET_EXPR_LOCUS (stmt, EXPR_LOCUS (orig_stmt));
2925 set_bb_for_stmt (stmt, bsi->bb);
2927 /* Preserve EH region information from the original statement, if
2928 requested by the caller. */
2931 eh_region = lookup_stmt_eh_region (orig_stmt);
2934 remove_stmt_from_eh_region (orig_stmt);
2935 add_stmt_to_eh_region (stmt, eh_region);
2939 delink_stmt_imm_use (orig_stmt);
2940 *bsi_stmt_ptr (*bsi) = stmt;
2941 mark_stmt_modified (stmt);
2942 update_modified_stmts (stmt);
2946 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2947 is made to place the statement in an existing basic block, but
2948 sometimes that isn't possible. When it isn't possible, the edge is
2949 split and the statement is added to the new block.
2951 In all cases, the returned *BSI points to the correct location. The
2952 return value is true if insertion should be done after the location,
2953 or false if it should be done before the location. If new basic block
2954 has to be created, it is stored in *NEW_BB. */
2957 tree_find_edge_insert_loc (edge e, block_stmt_iterator *bsi,
2958 basic_block *new_bb)
2960 basic_block dest, src;
2966 /* If the destination has one predecessor which has no PHI nodes,
2967 insert there. Except for the exit block.
2969 The requirement for no PHI nodes could be relaxed. Basically we
2970 would have to examine the PHIs to prove that none of them used
2971 the value set by the statement we want to insert on E. That
2972 hardly seems worth the effort. */
2973 if (single_pred_p (dest)
2974 && ! phi_nodes (dest)
2975 && dest != EXIT_BLOCK_PTR)
2977 *bsi = bsi_start (dest);
2978 if (bsi_end_p (*bsi))
2981 /* Make sure we insert after any leading labels. */
2982 tmp = bsi_stmt (*bsi);
2983 while (TREE_CODE (tmp) == LABEL_EXPR)
2986 if (bsi_end_p (*bsi))
2988 tmp = bsi_stmt (*bsi);
2991 if (bsi_end_p (*bsi))
2993 *bsi = bsi_last (dest);
3000 /* If the source has one successor, the edge is not abnormal and
3001 the last statement does not end a basic block, insert there.
3002 Except for the entry block. */
3004 if ((e->flags & EDGE_ABNORMAL) == 0
3005 && single_succ_p (src)
3006 && src != ENTRY_BLOCK_PTR)
3008 *bsi = bsi_last (src);
3009 if (bsi_end_p (*bsi))
3012 tmp = bsi_stmt (*bsi);
3013 if (!stmt_ends_bb_p (tmp))
3016 /* Insert code just before returning the value. We may need to decompose
3017 the return in the case it contains non-trivial operand. */
3018 if (TREE_CODE (tmp) == RETURN_EXPR)
3020 tree op = TREE_OPERAND (tmp, 0);
3021 if (op && !is_gimple_val (op))
3023 gcc_assert (TREE_CODE (op) == MODIFY_EXPR);
3024 bsi_insert_before (bsi, op, BSI_NEW_STMT);
3025 TREE_OPERAND (tmp, 0) = TREE_OPERAND (op, 0);
3032 /* Otherwise, create a new basic block, and split this edge. */
3033 dest = split_edge (e);
3036 e = single_pred_edge (dest);
3041 /* This routine will commit all pending edge insertions, creating any new
3042 basic blocks which are necessary. */
3045 bsi_commit_edge_inserts (void)
3051 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);
3054 FOR_EACH_EDGE (e, ei, bb->succs)
3055 bsi_commit_one_edge_insert (e, NULL);
3059 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3060 to this block, otherwise set it to NULL. */
3063 bsi_commit_one_edge_insert (edge e, basic_block *new_bb)
3067 if (PENDING_STMT (e))
3069 block_stmt_iterator bsi;
3070 tree stmt = PENDING_STMT (e);
3072 PENDING_STMT (e) = NULL_TREE;
3074 if (tree_find_edge_insert_loc (e, &bsi, new_bb))
3075 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3077 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3082 /* Add STMT to the pending list of edge E. No actual insertion is
3083 made until a call to bsi_commit_edge_inserts () is made. */
3086 bsi_insert_on_edge (edge e, tree stmt)
3088 append_to_statement_list (stmt, &PENDING_STMT (e));
3091 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3092 block has to be created, it is returned. */
3095 bsi_insert_on_edge_immediate (edge e, tree stmt)
3097 block_stmt_iterator bsi;
3098 basic_block new_bb = NULL;
3100 gcc_assert (!PENDING_STMT (e));
3102 if (tree_find_edge_insert_loc (e, &bsi, &new_bb))
3103 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
3105 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
3110 /*---------------------------------------------------------------------------
3111 Tree specific functions for CFG manipulation
3112 ---------------------------------------------------------------------------*/
3114 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3117 reinstall_phi_args (edge new_edge, edge old_edge)
3121 if (!PENDING_STMT (old_edge))
3124 for (var = PENDING_STMT (old_edge), phi = phi_nodes (new_edge->dest);
3126 var = TREE_CHAIN (var), phi = PHI_CHAIN (phi))
3128 tree result = TREE_PURPOSE (var);
3129 tree arg = TREE_VALUE (var);
3131 gcc_assert (result == PHI_RESULT (phi));
3133 add_phi_arg (phi, arg, new_edge);
3136 PENDING_STMT (old_edge) = NULL;
3139 /* Returns the basic block after which the new basic block created
3140 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3141 near its "logical" location. This is of most help to humans looking
3142 at debugging dumps. */
3145 split_edge_bb_loc (edge edge_in)
3147 basic_block dest = edge_in->dest;
3149 if (dest->prev_bb && find_edge (dest->prev_bb, dest))
3150 return edge_in->src;
3152 return dest->prev_bb;
3155 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3156 Abort on abnormal edges. */
3159 tree_split_edge (edge edge_in)
3161 basic_block new_bb, after_bb, dest;
3164 /* Abnormal edges cannot be split. */
3165 gcc_assert (!(edge_in->flags & EDGE_ABNORMAL));
3167 dest = edge_in->dest;
3169 after_bb = split_edge_bb_loc (edge_in);
3171 new_bb = create_empty_bb (after_bb);
3172 new_bb->frequency = EDGE_FREQUENCY (edge_in);
3173 new_bb->count = edge_in->count;
3174 new_edge = make_edge (new_bb, dest, EDGE_FALLTHRU);
3175 new_edge->probability = REG_BR_PROB_BASE;
3176 new_edge->count = edge_in->count;
3178 e = redirect_edge_and_branch (edge_in, new_bb);
3180 reinstall_phi_args (new_edge, e);
3186 /* Return true when BB has label LABEL in it. */
3189 has_label_p (basic_block bb, tree label)
3191 block_stmt_iterator bsi;
3193 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3195 tree stmt = bsi_stmt (bsi);
3197 if (TREE_CODE (stmt) != LABEL_EXPR)
3199 if (LABEL_EXPR_LABEL (stmt) == label)
3206 /* Callback for walk_tree, check that all elements with address taken are
3207 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3208 inside a PHI node. */
3211 verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
3214 bool in_phi = (data != NULL);
3219 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3220 #define CHECK_OP(N, MSG) \
3221 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3222 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3224 switch (TREE_CODE (t))
3227 if (SSA_NAME_IN_FREE_LIST (t))
3229 error ("SSA name in freelist but still referenced");
3235 x = fold (ASSERT_EXPR_COND (t));
3236 if (x == boolean_false_node)
3238 error ("ASSERT_EXPR with an always-false condition");
3244 x = TREE_OPERAND (t, 0);
3245 if (TREE_CODE (x) == BIT_FIELD_REF
3246 && is_gimple_reg (TREE_OPERAND (x, 0)))
3248 error ("GIMPLE register modified with BIT_FIELD_REF");
3257 bool old_side_effects;
3260 bool new_side_effects;
3262 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3263 dead PHIs that take the address of something. But if the PHI
3264 result is dead, the fact that it takes the address of anything
3265 is irrelevant. Because we can not tell from here if a PHI result
3266 is dead, we just skip this check for PHIs altogether. This means
3267 we may be missing "valid" checks, but what can you do?
3268 This was PR19217. */
3272 old_invariant = TREE_INVARIANT (t);
3273 old_constant = TREE_CONSTANT (t);
3274 old_side_effects = TREE_SIDE_EFFECTS (t);
3276 recompute_tree_invariant_for_addr_expr (t);
3277 new_invariant = TREE_INVARIANT (t);
3278 new_side_effects = TREE_SIDE_EFFECTS (t);
3279 new_constant = TREE_CONSTANT (t);
3281 if (old_invariant != new_invariant)
3283 error ("invariant not recomputed when ADDR_EXPR changed");
3287 if (old_constant != new_constant)
3289 error ("constant not recomputed when ADDR_EXPR changed");
3292 if (old_side_effects != new_side_effects)
3294 error ("side effects not recomputed when ADDR_EXPR changed");
3298 /* Skip any references (they will be checked when we recurse down the
3299 tree) and ensure that any variable used as a prefix is marked
3301 for (x = TREE_OPERAND (t, 0);
3302 handled_component_p (x);
3303 x = TREE_OPERAND (x, 0))
3306 if (TREE_CODE (x) != VAR_DECL && TREE_CODE (x) != PARM_DECL)
3308 if (!TREE_ADDRESSABLE (x))
3310 error ("address taken, but ADDRESSABLE bit not set");
3317 x = COND_EXPR_COND (t);
3318 if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
3320 error ("non-boolean used in condition");
3323 if (!is_gimple_condexpr (x))
3325 error ("invalid conditional operand");
3332 case FIX_TRUNC_EXPR:
3337 case NON_LVALUE_EXPR:
3338 case TRUTH_NOT_EXPR:
3339 CHECK_OP (0, "invalid operand to unary operator");
3346 case ARRAY_RANGE_REF:
3348 case VIEW_CONVERT_EXPR:
3349 /* We have a nest of references. Verify that each of the operands
3350 that determine where to reference is either a constant or a variable,
3351 verify that the base is valid, and then show we've already checked
3353 while (handled_component_p (t))
3355 if (TREE_CODE (t) == COMPONENT_REF && TREE_OPERAND (t, 2))
3356 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3357 else if (TREE_CODE (t) == ARRAY_REF
3358 || TREE_CODE (t) == ARRAY_RANGE_REF)
3360 CHECK_OP (1, "invalid array index");
3361 if (TREE_OPERAND (t, 2))
3362 CHECK_OP (2, "invalid array lower bound");
3363 if (TREE_OPERAND (t, 3))
3364 CHECK_OP (3, "invalid array stride");
3366 else if (TREE_CODE (t) == BIT_FIELD_REF)
3368 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3369 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3372 t = TREE_OPERAND (t, 0);
3375 if (!CONSTANT_CLASS_P (t) && !is_gimple_lvalue (t))
3377 error ("invalid reference prefix");
3389 case UNORDERED_EXPR:
3400 case TRUNC_DIV_EXPR:
3402 case FLOOR_DIV_EXPR:
3403 case ROUND_DIV_EXPR:
3404 case TRUNC_MOD_EXPR:
3406 case FLOOR_MOD_EXPR:
3407 case ROUND_MOD_EXPR:
3409 case EXACT_DIV_EXPR:
3419 CHECK_OP (0, "invalid operand to binary operator");
3420 CHECK_OP (1, "invalid operand to binary operator");
3424 if (TREE_CONSTANT (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
3437 /* Verify STMT, return true if STMT is not in GIMPLE form.
3438 TODO: Implement type checking. */
3441 verify_stmt (tree stmt, bool last_in_block)
3445 if (OMP_DIRECTIVE_P (stmt))
3447 /* OpenMP directives are validated by the FE and never operated
3448 on by the optimizers. Furthermore, OMP_FOR may contain
3449 non-gimple expressions when the main index variable has had
3450 its address taken. This does not affect the loop itself
3451 because the header of an OMP_FOR is merely used to determine
3452 how to setup the parallel iteration. */
3456 if (!is_gimple_stmt (stmt))
3458 error ("is not a valid GIMPLE statement");
3462 addr = walk_tree (&stmt, verify_expr, NULL, NULL);
3465 debug_generic_stmt (addr);
3469 /* If the statement is marked as part of an EH region, then it is
3470 expected that the statement could throw. Verify that when we
3471 have optimizations that simplify statements such that we prove
3472 that they cannot throw, that we update other data structures
3474 if (lookup_stmt_eh_region (stmt) >= 0)
3476 if (!tree_could_throw_p (stmt))
3478 error ("statement marked for throw, but doesn%'t");
3481 if (!last_in_block && tree_can_throw_internal (stmt))
3483 error ("statement marked for throw in middle of block");
3491 debug_generic_stmt (stmt);
3496 /* Return true when the T can be shared. */
3499 tree_node_can_be_shared (tree t)
3501 if (IS_TYPE_OR_DECL_P (t)
3502 || is_gimple_min_invariant (t)
3503 || TREE_CODE (t) == SSA_NAME
3504 || t == error_mark_node
3505 || TREE_CODE (t) == IDENTIFIER_NODE)
3508 if (TREE_CODE (t) == CASE_LABEL_EXPR)
3511 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
3512 && is_gimple_min_invariant (TREE_OPERAND (t, 1)))
3513 || TREE_CODE (t) == COMPONENT_REF
3514 || TREE_CODE (t) == REALPART_EXPR
3515 || TREE_CODE (t) == IMAGPART_EXPR)
3516 t = TREE_OPERAND (t, 0);
3525 /* Called via walk_trees. Verify tree sharing. */
3528 verify_node_sharing (tree * tp, int *walk_subtrees, void *data)
3530 htab_t htab = (htab_t) data;
3533 if (tree_node_can_be_shared (*tp))
3535 *walk_subtrees = false;
3539 slot = htab_find_slot (htab, *tp, INSERT);
3541 return (tree) *slot;
3548 /* Verify the GIMPLE statement chain. */
3554 block_stmt_iterator bsi;
3559 timevar_push (TV_TREE_STMT_VERIFY);
3560 htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
3567 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
3569 int phi_num_args = PHI_NUM_ARGS (phi);
3571 if (bb_for_stmt (phi) != bb)
3573 error ("bb_for_stmt (phi) is set to a wrong basic block");
3577 for (i = 0; i < phi_num_args; i++)
3579 tree t = PHI_ARG_DEF (phi, i);
3582 /* Addressable variables do have SSA_NAMEs but they
3583 are not considered gimple values. */
3584 if (TREE_CODE (t) != SSA_NAME
3585 && TREE_CODE (t) != FUNCTION_DECL
3586 && !is_gimple_val (t))
3588 error ("PHI def is not a GIMPLE value");
3589 debug_generic_stmt (phi);
3590 debug_generic_stmt (t);
3594 addr = walk_tree (&t, verify_expr, (void *) 1, NULL);
3597 debug_generic_stmt (addr);
3601 addr = walk_tree (&t, verify_node_sharing, htab, NULL);
3604 error ("incorrect sharing of tree nodes");
3605 debug_generic_stmt (phi);
3606 debug_generic_stmt (addr);
3612 for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
3614 tree stmt = bsi_stmt (bsi);
3616 if (bb_for_stmt (stmt) != bb)
3618 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3623 err |= verify_stmt (stmt, bsi_end_p (bsi));
3624 addr = walk_tree (&stmt, verify_node_sharing, htab, NULL);
3627 error ("incorrect sharing of tree nodes");
3628 debug_generic_stmt (stmt);
3629 debug_generic_stmt (addr);
3636 internal_error ("verify_stmts failed");
3639 timevar_pop (TV_TREE_STMT_VERIFY);
3643 /* Verifies that the flow information is OK. */
3646 tree_verify_flow_info (void)
3650 block_stmt_iterator bsi;
3655 if (ENTRY_BLOCK_PTR->stmt_list)
3657 error ("ENTRY_BLOCK has a statement list associated with it");
3661 if (EXIT_BLOCK_PTR->stmt_list)
3663 error ("EXIT_BLOCK has a statement list associated with it");
3667 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
3668 if (e->flags & EDGE_FALLTHRU)
3670 error ("fallthru to exit from bb %d", e->src->index);
3676 bool found_ctrl_stmt = false;
3680 /* Skip labels on the start of basic block. */
3681 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
3683 tree prev_stmt = stmt;
3685 stmt = bsi_stmt (bsi);
3687 if (TREE_CODE (stmt) != LABEL_EXPR)
3690 if (prev_stmt && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
3692 error ("nonlocal label ");
3693 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3694 fprintf (stderr, " is not first in a sequence of labels in bb %d",
3699 if (label_to_block (LABEL_EXPR_LABEL (stmt)) != bb)
3702 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3703 fprintf (stderr, " to block does not match in bb %d",
3708 if (decl_function_context (LABEL_EXPR_LABEL (stmt))
3709 != current_function_decl)
3712 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3713 fprintf (stderr, " has incorrect context in bb %d",
3719 /* Verify that body of basic block BB is free of control flow. */
3720 for (; !bsi_end_p (bsi); bsi_next (&bsi))
3722 tree stmt = bsi_stmt (bsi);
3724 if (found_ctrl_stmt)
3726 error ("control flow in the middle of basic block %d",
3731 if (stmt_ends_bb_p (stmt))
3732 found_ctrl_stmt = true;
3734 if (TREE_CODE (stmt) == LABEL_EXPR)
3737 print_generic_expr (stderr, LABEL_EXPR_LABEL (stmt), 0);
3738 fprintf (stderr, " in the middle of basic block %d", bb->index);
3743 bsi = bsi_last (bb);
3744 if (bsi_end_p (bsi))
3747 stmt = bsi_stmt (bsi);
3749 err |= verify_eh_edges (stmt);
3751 if (is_ctrl_stmt (stmt))
3753 FOR_EACH_EDGE (e, ei, bb->succs)
3754 if (e->flags & EDGE_FALLTHRU)
3756 error ("fallthru edge after a control statement in bb %d",
3762 if (TREE_CODE (stmt) != COND_EXPR)
3764 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3765 after anything else but if statement. */
3766 FOR_EACH_EDGE (e, ei, bb->succs)
3767 if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE))
3769 error ("true/false edge after a non-COND_EXPR in bb %d",
3775 switch (TREE_CODE (stmt))
3781 if (TREE_CODE (COND_EXPR_THEN (stmt)) != GOTO_EXPR
3782 || TREE_CODE (COND_EXPR_ELSE (stmt)) != GOTO_EXPR)
3784 error ("structured COND_EXPR at the end of bb %d", bb->index);
3788 extract_true_false_edges_from_block (bb, &true_edge, &false_edge);
3790 if (!true_edge || !false_edge
3791 || !(true_edge->flags & EDGE_TRUE_VALUE)
3792 || !(false_edge->flags & EDGE_FALSE_VALUE)
3793 || (true_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3794 || (false_edge->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL))
3795 || EDGE_COUNT (bb->succs) >= 3)
3797 error ("wrong outgoing edge flags at end of bb %d",
3802 if (!has_label_p (true_edge->dest,
3803 GOTO_DESTINATION (COND_EXPR_THEN (stmt))))
3805 error ("%<then%> label does not match edge at end of bb %d",
3810 if (!has_label_p (false_edge->dest,
3811 GOTO_DESTINATION (COND_EXPR_ELSE (stmt))))
3813 error ("%<else%> label does not match edge at end of bb %d",
3821 if (simple_goto_p (stmt))
3823 error ("explicit goto at end of bb %d", bb->index);
3828 /* FIXME. We should double check that the labels in the
3829 destination blocks have their address taken. */
3830 FOR_EACH_EDGE (e, ei, bb->succs)
3831 if ((e->flags & (EDGE_FALLTHRU | EDGE_TRUE_VALUE
3832 | EDGE_FALSE_VALUE))
3833 || !(e->flags & EDGE_ABNORMAL))
3835 error ("wrong outgoing edge flags at end of bb %d",
3843 if (!single_succ_p (bb)
3844 || (single_succ_edge (bb)->flags
3845 & (EDGE_FALLTHRU | EDGE_ABNORMAL
3846 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3848 error ("wrong outgoing edge flags at end of bb %d", bb->index);
3851 if (single_succ (bb) != EXIT_BLOCK_PTR)
3853 error ("return edge does not point to exit in bb %d",
3866 vec = SWITCH_LABELS (stmt);
3867 n = TREE_VEC_LENGTH (vec);
3869 /* Mark all the destination basic blocks. */
3870 for (i = 0; i < n; ++i)
3872 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3873 basic_block label_bb = label_to_block (lab);
3875 gcc_assert (!label_bb->aux || label_bb->aux == (void *)1);
3876 label_bb->aux = (void *)1;
3879 /* Verify that the case labels are sorted. */
3880 prev = TREE_VEC_ELT (vec, 0);
3881 for (i = 1; i < n - 1; ++i)
3883 tree c = TREE_VEC_ELT (vec, i);
3886 error ("found default case not at end of case vector");
3890 if (! tree_int_cst_lt (CASE_LOW (prev), CASE_LOW (c)))
3892 error ("case labels not sorted: ");
3893 print_generic_expr (stderr, prev, 0);
3894 fprintf (stderr," is greater than ");
3895 print_generic_expr (stderr, c, 0);
3896 fprintf (stderr," but comes before it.\n");
3901 if (CASE_LOW (TREE_VEC_ELT (vec, n - 1)))
3903 error ("no default case found at end of case vector");
3907 FOR_EACH_EDGE (e, ei, bb->succs)
3911 error ("extra outgoing edge %d->%d",
3912 bb->index, e->dest->index);
3915 e->dest->aux = (void *)2;
3916 if ((e->flags & (EDGE_FALLTHRU | EDGE_ABNORMAL
3917 | EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)))
3919 error ("wrong outgoing edge flags at end of bb %d",
3925 /* Check that we have all of them. */
3926 for (i = 0; i < n; ++i)
3928 tree lab = CASE_LABEL (TREE_VEC_ELT (vec, i));
3929 basic_block label_bb = label_to_block (lab);
3931 if (label_bb->aux != (void *)2)
3933 error ("missing edge %i->%i",
3934 bb->index, label_bb->index);
3939 FOR_EACH_EDGE (e, ei, bb->succs)
3940 e->dest->aux = (void *)0;
3947 if (dom_computed[CDI_DOMINATORS] >= DOM_NO_FAST_QUERY)
3948 verify_dominators (CDI_DOMINATORS);
3954 /* Updates phi nodes after creating a forwarder block joined
3955 by edge FALLTHRU. */
3958 tree_make_forwarder_block (edge fallthru)
3962 basic_block dummy, bb;
3963 tree phi, new_phi, var;
3965 dummy = fallthru->src;
3966 bb = fallthru->dest;
3968 if (single_pred_p (bb))
3971 /* If we redirected a branch we must create new phi nodes at the
3973 for (phi = phi_nodes (dummy); phi; phi = PHI_CHAIN (phi))
3975 var = PHI_RESULT (phi);
3976 new_phi = create_phi_node (var, bb);
3977 SSA_NAME_DEF_STMT (var) = new_phi;
3978 SET_PHI_RESULT (phi, make_ssa_name (SSA_NAME_VAR (var), phi));
3979 add_phi_arg (new_phi, PHI_RESULT (phi), fallthru);
3982 /* Ensure that the PHI node chain is in the same order. */
3983 set_phi_nodes (bb, phi_reverse (phi_nodes (bb)));
3985 /* Add the arguments we have stored on edges. */
3986 FOR_EACH_EDGE (e, ei, bb->preds)
3991 flush_pending_stmts (e);
3996 /* Return a non-special label in the head of basic block BLOCK.
3997 Create one if it doesn't exist. */
4000 tree_block_label (basic_block bb)
4002 block_stmt_iterator i, s = bsi_start (bb);
4006 for (i = s; !bsi_end_p (i); first = false, bsi_next (&i))
4008 stmt = bsi_stmt (i);
4009 if (TREE_CODE (stmt) != LABEL_EXPR)
4011 label = LABEL_EXPR_LABEL (stmt);
4012 if (!DECL_NONLOCAL (label))
4015 bsi_move_before (&i, &s);
4020 label = create_artificial_label ();
4021 stmt = build1 (LABEL_EXPR, void_type_node, label);
4022 bsi_insert_before (&s, stmt, BSI_NEW_STMT);
4027 /* Attempt to perform edge redirection by replacing a possibly complex
4028 jump instruction by a goto or by removing the jump completely.
4029 This can apply only if all edges now point to the same block. The
4030 parameters and return values are equivalent to
4031 redirect_edge_and_branch. */
4034 tree_try_redirect_by_replacing_jump (edge e, basic_block target)
4036 basic_block src = e->src;
4037 block_stmt_iterator b;
4040 /* We can replace or remove a complex jump only when we have exactly
4042 if (EDGE_COUNT (src->succs) != 2
4043 /* Verify that all targets will be TARGET. Specifically, the
4044 edge that is not E must also go to TARGET. */
4045 || EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest != target)
4051 stmt = bsi_stmt (b);
4053 if (TREE_CODE (stmt) == COND_EXPR
4054 || TREE_CODE (stmt) == SWITCH_EXPR)
4056 bsi_remove (&b, true);
4057 e = ssa_redirect_edge (e, target);
4058 e->flags = EDGE_FALLTHRU;
4066 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4067 edge representing the redirected branch. */
4070 tree_redirect_edge_and_branch (edge e, basic_block dest)
4072 basic_block bb = e->src;
4073 block_stmt_iterator bsi;
4077 if (e->flags & EDGE_ABNORMAL)
4080 if (e->src != ENTRY_BLOCK_PTR
4081 && (ret = tree_try_redirect_by_replacing_jump (e, dest)))
4084 if (e->dest == dest)
4087 label = tree_block_label (dest);
4089 bsi = bsi_last (bb);
4090 stmt = bsi_end_p (bsi) ? NULL : bsi_stmt (bsi);
4092 switch (stmt ? TREE_CODE (stmt) : ERROR_MARK)
4095 stmt = (e->flags & EDGE_TRUE_VALUE
4096 ? COND_EXPR_THEN (stmt)
4097 : COND_EXPR_ELSE (stmt));
4098 GOTO_DESTINATION (stmt) = label;
4102 /* No non-abnormal edges should lead from a non-simple goto, and
4103 simple ones should be represented implicitly. */
4108 tree cases = get_cases_for_edge (e, stmt);
4110 /* If we have a list of cases associated with E, then use it
4111 as it's a lot faster than walking the entire case vector. */
4114 edge e2 = find_edge (e->src, dest);
4121 CASE_LABEL (cases) = label;
4122 cases = TREE_CHAIN (cases);
4125 /* If there was already an edge in the CFG, then we need
4126 to move all the cases associated with E to E2. */
4129 tree cases2 = get_cases_for_edge (e2, stmt);
4131 TREE_CHAIN (last) = TREE_CHAIN (cases2);
4132 TREE_CHAIN (cases2) = first;
4137 tree vec = SWITCH_LABELS (stmt);
4138 size_t i, n = TREE_VEC_LENGTH (vec);
4140 for (i = 0; i < n; i++)
4142 tree elt = TREE_VEC_ELT (vec, i);
4144 if (label_to_block (CASE_LABEL (elt)) == e->dest)
4145 CASE_LABEL (elt) = label;
4153 bsi_remove (&bsi, true);
4154 e->flags |= EDGE_FALLTHRU;
4158 /* Otherwise it must be a fallthru edge, and we don't need to
4159 do anything besides redirecting it. */
4160 gcc_assert (e->flags & EDGE_FALLTHRU);
4164 /* Update/insert PHI nodes as necessary. */
4166 /* Now update the edges in the CFG. */
4167 e = ssa_redirect_edge (e, dest);
4173 /* Simple wrapper, as we can always redirect fallthru edges. */
4176 tree_redirect_edge_and_branch_force (edge e, basic_block dest)
4178 e = tree_redirect_edge_and_branch (e, dest);
4185 /* Splits basic block BB after statement STMT (but at least after the
4186 labels). If STMT is NULL, BB is split just after the labels. */
4189 tree_split_block (basic_block bb, void *stmt)
4191 block_stmt_iterator bsi;
4192 tree_stmt_iterator tsi_tgt;
4198 new_bb = create_empty_bb (bb);
4200 /* Redirect the outgoing edges. */
4201 new_bb->succs = bb->succs;
4203 FOR_EACH_EDGE (e, ei, new_bb->succs)
4206 if (stmt && TREE_CODE ((tree) stmt) == LABEL_EXPR)
4209 /* Move everything from BSI to the new basic block. */
4210 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4212 act = bsi_stmt (bsi);
4213 if (TREE_CODE (act) == LABEL_EXPR)
4226 if (bsi_end_p (bsi))
4229 /* Split the statement list - avoid re-creating new containers as this
4230 brings ugly quadratic memory consumption in the inliner.
4231 (We are still quadratic since we need to update stmt BB pointers,
4233 new_bb->stmt_list = tsi_split_statement_list_before (&bsi.tsi);
4234 for (tsi_tgt = tsi_start (new_bb->stmt_list);
4235 !tsi_end_p (tsi_tgt); tsi_next (&tsi_tgt))
4236 change_bb_for_stmt (tsi_stmt (tsi_tgt), new_bb);
4242 /* Moves basic block BB after block AFTER. */
4245 tree_move_block_after (basic_block bb, basic_block after)
4247 if (bb->prev_bb == after)
4251 link_block (bb, after);
4257 /* Return true if basic_block can be duplicated. */
4260 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED)
4266 /* Create a duplicate of the basic block BB. NOTE: This does not
4267 preserve SSA form. */
4270 tree_duplicate_bb (basic_block bb)
4273 block_stmt_iterator bsi, bsi_tgt;
4276 new_bb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb);
4278 /* Copy the PHI nodes. We ignore PHI node arguments here because
4279 the incoming edges have not been setup yet. */
4280 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4282 tree copy = create_phi_node (PHI_RESULT (phi), new_bb);
4283 create_new_def_for (PHI_RESULT (copy), copy, PHI_RESULT_PTR (copy));
4286 /* Keep the chain of PHI nodes in the same order so that they can be
4287 updated by ssa_redirect_edge. */
4288 set_phi_nodes (new_bb, phi_reverse (phi_nodes (new_bb)));
4290 bsi_tgt = bsi_start (new_bb);
4291 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
4293 def_operand_p def_p;
4294 ssa_op_iter op_iter;
4298 stmt = bsi_stmt (bsi);
4299 if (TREE_CODE (stmt) == LABEL_EXPR)
4302 /* Create a new copy of STMT and duplicate STMT's virtual
4304 copy = unshare_expr (stmt);
4305 bsi_insert_after (&bsi_tgt, copy, BSI_NEW_STMT);
4306 copy_virtual_operands (copy, stmt);
4307 region = lookup_stmt_eh_region (stmt);
4309 add_stmt_to_eh_region (copy, region);
4311 /* Create new names for all the definitions created by COPY and
4312 add replacement mappings for each new name. */
4313 FOR_EACH_SSA_DEF_OPERAND (def_p, copy, op_iter, SSA_OP_ALL_DEFS)
4314 create_new_def_for (DEF_FROM_PTR (def_p), copy, def_p);
4321 /* Basic block BB_COPY was created by code duplication. Add phi node
4322 arguments for edges going out of BB_COPY. The blocks that were
4323 duplicated have BB_DUPLICATED set. */
4326 add_phi_args_after_copy_bb (basic_block bb_copy)
4328 basic_block bb, dest;
4331 tree phi, phi_copy, phi_next, def;
4333 bb = get_bb_original (bb_copy);
4335 FOR_EACH_EDGE (e_copy, ei, bb_copy->succs)
4337 if (!phi_nodes (e_copy->dest))
4340 if (e_copy->dest->flags & BB_DUPLICATED)
4341 dest = get_bb_original (e_copy->dest);
4343 dest = e_copy->dest;
4345 e = find_edge (bb, dest);
4348 /* During loop unrolling the target of the latch edge is copied.
4349 In this case we are not looking for edge to dest, but to
4350 duplicated block whose original was dest. */
4351 FOR_EACH_EDGE (e, ei, bb->succs)
4352 if ((e->dest->flags & BB_DUPLICATED)
4353 && get_bb_original (e->dest) == dest)
4356 gcc_assert (e != NULL);
4359 for (phi = phi_nodes (e->dest), phi_copy = phi_nodes (e_copy->dest);
4361 phi = phi_next, phi_copy = PHI_CHAIN (phi_copy))
4363 phi_next = PHI_CHAIN (phi);
4364 def = PHI_ARG_DEF_FROM_EDGE (phi, e);
4365 add_phi_arg (phi_copy, def, e_copy);
4370 /* Blocks in REGION_COPY array of length N_REGION were created by
4371 duplication of basic blocks. Add phi node arguments for edges
4372 going from these blocks. */
4375 add_phi_args_after_copy (basic_block *region_copy, unsigned n_region)
4379 for (i = 0; i < n_region; i++)
4380 region_copy[i]->flags |= BB_DUPLICATED;
4382 for (i = 0; i < n_region; i++)
4383 add_phi_args_after_copy_bb (region_copy[i]);
4385 for (i = 0; i < n_region; i++)
4386 region_copy[i]->flags &= ~BB_DUPLICATED;
4389 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4390 important exit edge EXIT. By important we mean that no SSA name defined
4391 inside region is live over the other exit edges of the region. All entry
4392 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4393 to the duplicate of the region. SSA form, dominance and loop information
4394 is updated. The new basic blocks are stored to REGION_COPY in the same
4395 order as they had in REGION, provided that REGION_COPY is not NULL.
4396 The function returns false if it is unable to copy the region,
4400 tree_duplicate_sese_region (edge entry, edge exit,
4401 basic_block *region, unsigned n_region,
4402 basic_block *region_copy)
4405 bool free_region_copy = false, copying_header = false;
4406 struct loop *loop = entry->dest->loop_father;
4410 int total_freq = 0, entry_freq = 0;
4411 gcov_type total_count = 0, entry_count = 0;
4413 if (!can_copy_bbs_p (region, n_region))
4416 /* Some sanity checking. Note that we do not check for all possible
4417 missuses of the functions. I.e. if you ask to copy something weird,
4418 it will work, but the state of structures probably will not be
4420 for (i = 0; i < n_region; i++)
4422 /* We do not handle subloops, i.e. all the blocks must belong to the
4424 if (region[i]->loop_father != loop)
4427 if (region[i] != entry->dest
4428 && region[i] == loop->header)
4434 /* In case the function is used for loop header copying (which is the primary
4435 use), ensure that EXIT and its copy will be new latch and entry edges. */
4436 if (loop->header == entry->dest)
4438 copying_header = true;
4439 loop->copy = loop->outer;
4441 if (!dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src))
4444 for (i = 0; i < n_region; i++)
4445 if (region[i] != exit->src
4446 && dominated_by_p (CDI_DOMINATORS, region[i], exit->src))
4452 region_copy = XNEWVEC (basic_block, n_region);
4453 free_region_copy = true;
4456 gcc_assert (!need_ssa_update_p ());
4458 /* Record blocks outside the region that are dominated by something
4460 doms = XNEWVEC (basic_block, n_basic_blocks);
4461 initialize_original_copy_tables ();
4463 n_doms = get_dominated_by_region (CDI_DOMINATORS, region, n_region, doms);
4465 if (entry->dest->count)
4467 total_count = entry->dest->count;
4468 entry_count = entry->count;
4469 /* Fix up corner cases, to avoid division by zero or creation of negative
4471 if (entry_count > total_count)
4472 entry_count = total_count;
4476 total_freq = entry->dest->frequency;
4477 entry_freq = EDGE_FREQUENCY (entry);
4478 /* Fix up corner cases, to avoid division by zero or creation of negative
4480 if (total_freq == 0)
4482 else if (entry_freq > total_freq)
4483 entry_freq = total_freq;
4486 copy_bbs (region, n_region, region_copy, &exit, 1, &exit_copy, loop,
4487 split_edge_bb_loc (entry));
4490 scale_bbs_frequencies_gcov_type (region, n_region,
4491 total_count - entry_count,
4493 scale_bbs_frequencies_gcov_type (region_copy, n_region, entry_count,
4498 scale_bbs_frequencies_int (region, n_region, total_freq - entry_freq,
4500 scale_bbs_frequencies_int (region_copy, n_region, entry_freq, total_freq);
4505 loop->header = exit->dest;
4506 loop->latch = exit->src;
4509 /* Redirect the entry and add the phi node arguments. */
4510 redirected = redirect_edge_and_branch (entry, get_bb_copy (entry->dest));
4511 gcc_assert (redirected != NULL);
4512 flush_pending_stmts (entry);
4514 /* Concerning updating of dominators: We must recount dominators
4515 for entry block and its copy. Anything that is outside of the
4516 region, but was dominated by something inside needs recounting as
4518 set_immediate_dominator (CDI_DOMINATORS, entry->dest, entry->src);
4519 doms[n_doms++] = get_bb_original (entry->dest);
4520 iterate_fix_dominators (CDI_DOMINATORS, doms, n_doms);
4523 /* Add the other PHI node arguments. */
4524 add_phi_args_after_copy (region_copy, n_region);
4526 /* Update the SSA web. */
4527 update_ssa (TODO_update_ssa);
4529 if (free_region_copy)
4532 free_original_copy_tables ();
4537 DEF_VEC_P(basic_block);
4538 DEF_VEC_ALLOC_P(basic_block,heap);
4541 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4542 adding blocks when the dominator traversal reaches EXIT. This
4543 function silently assumes that ENTRY strictly dominates EXIT. */
4546 gather_blocks_in_sese_region (basic_block entry, basic_block exit,
4547 VEC(basic_block,heap) **bbs_p)
4551 for (son = first_dom_son (CDI_DOMINATORS, entry);
4553 son = next_dom_son (CDI_DOMINATORS, son))
4555 VEC_safe_push (basic_block, heap, *bbs_p, son);
4557 gather_blocks_in_sese_region (son, exit, bbs_p);
4567 bitmap vars_to_remove;
4568 htab_t new_label_map;
4572 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4573 contained in *TP and change the DECL_CONTEXT of every local
4574 variable referenced in *TP. */
4577 move_stmt_r (tree *tp, int *walk_subtrees, void *data)
4579 struct move_stmt_d *p = (struct move_stmt_d *) data;
4582 if (p->block && IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t))))
4583 TREE_BLOCK (t) = p->block;
4585 if (OMP_DIRECTIVE_P (t)
4586 && TREE_CODE (t) != OMP_RETURN
4587 && TREE_CODE (t) != OMP_CONTINUE)
4589 /* Do not remap variables inside OMP directives. Variables
4590 referenced in clauses and directive header belong to the
4591 parent function and should not be moved into the child
4593 bool save_remap_decls_p = p->remap_decls_p;
4594 p->remap_decls_p = false;
4597 walk_tree (&OMP_BODY (t), move_stmt_r, p, NULL);
4599 p->remap_decls_p = save_remap_decls_p;
4601 else if (DECL_P (t) && DECL_CONTEXT (t) == p->from_context)
4603 if (TREE_CODE (t) == LABEL_DECL)
4605 if (p->new_label_map)
4607 struct tree_map in, *out;
4609 out = htab_find_with_hash (p->new_label_map, &in, DECL_UID (t));
4614 DECL_CONTEXT (t) = p->to_context;
4616 else if (p->remap_decls_p)
4618 DECL_CONTEXT (t) = p->to_context;
4620 if (TREE_CODE (t) == VAR_DECL)
4622 struct function *f = DECL_STRUCT_FUNCTION (p->to_context);
4623 f->unexpanded_var_list
4624 = tree_cons (0, t, f->unexpanded_var_list);
4626 /* Mark T to be removed from the original function,
4627 otherwise it will be given a DECL_RTL when the
4628 original function is expanded. */
4629 bitmap_set_bit (p->vars_to_remove, DECL_UID (t));
4633 else if (TYPE_P (t))
4640 /* Move basic block BB from function CFUN to function DEST_FN. The
4641 block is moved out of the original linked list and placed after
4642 block AFTER in the new list. Also, the block is removed from the
4643 original array of blocks and placed in DEST_FN's array of blocks.
4644 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4645 updated to reflect the moved edges.
4647 On exit, local variables that need to be removed from
4648 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4651 move_block_to_fn (struct function *dest_cfun, basic_block bb,
4652 basic_block after, bool update_edge_count_p,
4653 bitmap vars_to_remove, htab_t new_label_map, int eh_offset)
4655 struct control_flow_graph *cfg;
4658 block_stmt_iterator si;
4659 struct move_stmt_d d;
4660 unsigned old_len, new_len;
4663 /* Link BB to the new linked list. */
4664 move_block_after (bb, after);
4666 /* Update the edge count in the corresponding flowgraphs. */
4667 if (update_edge_count_p)
4668 FOR_EACH_EDGE (e, ei, bb->succs)
4670 cfun->cfg->x_n_edges--;
4671 dest_cfun->cfg->x_n_edges++;
4674 /* Remove BB from the original basic block array. */
4675 VEC_replace (basic_block, cfun->cfg->x_basic_block_info, bb->index, NULL);
4676 cfun->cfg->x_n_basic_blocks--;
4678 /* Grow DEST_CFUN's basic block array if needed. */
4679 cfg = dest_cfun->cfg;
4680 cfg->x_n_basic_blocks++;
4681 if (bb->index > cfg->x_last_basic_block)
4682 cfg->x_last_basic_block = bb->index;
4684 old_len = VEC_length (basic_block, cfg->x_basic_block_info);
4685 if ((unsigned) cfg->x_last_basic_block >= old_len)
4687 new_len = cfg->x_last_basic_block + (cfg->x_last_basic_block + 3) / 4;
4688 VEC_safe_grow (basic_block, gc, cfg->x_basic_block_info, new_len);
4689 addr = VEC_address (basic_block, cfg->x_basic_block_info);
4690 memset (&addr[old_len], 0, sizeof (basic_block) * (new_len - old_len));
4693 VEC_replace (basic_block, cfg->x_basic_block_info,
4694 cfg->x_last_basic_block, bb);
4696 /* The statements in BB need to be associated with a new TREE_BLOCK.
4697 Labels need to be associated with a new label-to-block map. */
4698 memset (&d, 0, sizeof (d));
4699 d.vars_to_remove = vars_to_remove;
4701 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4703 tree stmt = bsi_stmt (si);
4706 d.from_context = cfun->decl;
4707 d.to_context = dest_cfun->decl;
4708 d.remap_decls_p = true;
4709 d.new_label_map = new_label_map;
4710 if (TREE_BLOCK (stmt))
4711 d.block = DECL_INITIAL (dest_cfun->decl);
4713 walk_tree (&stmt, move_stmt_r, &d, NULL);
4715 if (TREE_CODE (stmt) == LABEL_EXPR)
4717 tree label = LABEL_EXPR_LABEL (stmt);
4718 int uid = LABEL_DECL_UID (label);
4720 gcc_assert (uid > -1);
4722 old_len = VEC_length (basic_block, cfg->x_label_to_block_map);
4723 if (old_len <= (unsigned) uid)
4725 new_len = 3 * uid / 2;
4726 VEC_safe_grow (basic_block, gc, cfg->x_label_to_block_map,
4728 addr = VEC_address (basic_block, cfg->x_label_to_block_map);
4729 memset (&addr[old_len], 0,
4730 sizeof (basic_block) * (new_len - old_len));
4733 VEC_replace (basic_block, cfg->x_label_to_block_map, uid, bb);
4734 VEC_replace (basic_block, cfun->cfg->x_label_to_block_map, uid, NULL);
4736 gcc_assert (DECL_CONTEXT (label) == dest_cfun->decl);
4738 if (uid >= dest_cfun->last_label_uid)
4739 dest_cfun->last_label_uid = uid + 1;
4741 else if (TREE_CODE (stmt) == RESX_EXPR && eh_offset != 0)
4742 TREE_OPERAND (stmt, 0) =
4743 build_int_cst (NULL_TREE,
4744 TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0))
4747 region = lookup_stmt_eh_region (stmt);
4750 add_stmt_to_eh_region_fn (dest_cfun, stmt, region + eh_offset);
4751 remove_stmt_from_eh_region (stmt);
4756 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4757 the outermost EH region. Use REGION as the incoming base EH region. */
4760 find_outermost_region_in_block (struct function *src_cfun,
4761 basic_block bb, int region)
4763 block_stmt_iterator si;
4765 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4767 tree stmt = bsi_stmt (si);
4770 if (TREE_CODE (stmt) == RESX_EXPR)
4771 stmt_region = TREE_INT_CST_LOW (TREE_OPERAND (stmt, 0));
4773 stmt_region = lookup_stmt_eh_region_fn (src_cfun, stmt);
4774 if (stmt_region > 0)
4777 region = stmt_region;
4778 else if (stmt_region != region)
4780 region = eh_region_outermost (src_cfun, stmt_region, region);
4781 gcc_assert (region != -1);
4790 new_label_mapper (tree decl, void *data)
4792 htab_t hash = (htab_t) data;
4796 gcc_assert (TREE_CODE (decl) == LABEL_DECL);
4798 m = xmalloc (sizeof (struct tree_map));
4799 m->hash = DECL_UID (decl);
4801 m->to = create_artificial_label ();
4802 LABEL_DECL_UID (m->to) = LABEL_DECL_UID (decl);
4804 slot = htab_find_slot_with_hash (hash, m, m->hash, INSERT);
4805 gcc_assert (*slot == NULL);
4812 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4813 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4814 single basic block in the original CFG and the new basic block is
4815 returned. DEST_CFUN must not have a CFG yet.
4817 Note that the region need not be a pure SESE region. Blocks inside
4818 the region may contain calls to abort/exit. The only restriction
4819 is that ENTRY_BB should be the only entry point and it must
4822 All local variables referenced in the region are assumed to be in
4823 the corresponding BLOCK_VARS and unexpanded variable lists
4824 associated with DEST_CFUN. */
4827 move_sese_region_to_fn (struct function *dest_cfun, basic_block entry_bb,
4828 basic_block exit_bb)
4830 VEC(basic_block,heap) *bbs;
4831 basic_block after, bb, *entry_pred, *exit_succ;
4832 struct function *saved_cfun;
4833 int *entry_flag, *exit_flag, eh_offset;
4834 unsigned i, num_entry_edges, num_exit_edges;
4837 bitmap vars_to_remove;
4838 htab_t new_label_map;
4842 /* Collect all the blocks in the region. Manually add ENTRY_BB
4843 because it won't be added by dfs_enumerate_from. */
4844 calculate_dominance_info (CDI_DOMINATORS);
4846 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4848 gcc_assert (entry_bb != exit_bb
4850 || dominated_by_p (CDI_DOMINATORS, exit_bb, entry_bb)));
4853 VEC_safe_push (basic_block, heap, bbs, entry_bb);
4854 gather_blocks_in_sese_region (entry_bb, exit_bb, &bbs);
4856 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4857 the predecessor edges to ENTRY_BB and the successor edges to
4858 EXIT_BB so that we can re-attach them to the new basic block that
4859 will replace the region. */
4860 num_entry_edges = EDGE_COUNT (entry_bb->preds);
4861 entry_pred = (basic_block *) xcalloc (num_entry_edges, sizeof (basic_block));
4862 entry_flag = (int *) xcalloc (num_entry_edges, sizeof (int));
4864 for (ei = ei_start (entry_bb->preds); (e = ei_safe_edge (ei)) != NULL;)
4866 entry_flag[i] = e->flags;
4867 entry_pred[i++] = e->src;
4873 num_exit_edges = EDGE_COUNT (exit_bb->succs);
4874 exit_succ = (basic_block *) xcalloc (num_exit_edges,
4875 sizeof (basic_block));
4876 exit_flag = (int *) xcalloc (num_exit_edges, sizeof (int));
4878 for (ei = ei_start (exit_bb->succs); (e = ei_safe_edge (ei)) != NULL;)
4880 exit_flag[i] = e->flags;
4881 exit_succ[i++] = e->dest;
4892 /* Switch context to the child function to initialize DEST_FN's CFG. */
4893 gcc_assert (dest_cfun->cfg == NULL);
4896 init_empty_tree_cfg ();
4898 /* Initialize EH information for the new function. */
4900 new_label_map = NULL;
4905 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4906 region = find_outermost_region_in_block (saved_cfun, bb, region);
4908 init_eh_for_function ();
4911 new_label_map = htab_create (17, tree_map_hash, tree_map_eq, free);
4912 eh_offset = duplicate_eh_regions (saved_cfun, new_label_mapper,
4913 new_label_map, region, 0);
4919 /* Move blocks from BBS into DEST_CFUN. */
4920 gcc_assert (VEC_length (basic_block, bbs) >= 2);
4921 after = dest_cfun->cfg->x_entry_block_ptr;
4922 vars_to_remove = BITMAP_ALLOC (NULL);
4923 for (i = 0; VEC_iterate (basic_block, bbs, i, bb); i++)
4925 /* No need to update edge counts on the last block. It has
4926 already been updated earlier when we detached the region from
4927 the original CFG. */
4928 move_block_to_fn (dest_cfun, bb, after, bb != exit_bb, vars_to_remove,
4929 new_label_map, eh_offset);
4934 htab_delete (new_label_map);
4936 /* Remove the variables marked in VARS_TO_REMOVE from
4937 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4938 DECL_RTL in the context of CFUN. */
4939 if (!bitmap_empty_p (vars_to_remove))
4943 for (p = &cfun->unexpanded_var_list; *p; )
4945 tree var = TREE_VALUE (*p);
4946 if (bitmap_bit_p (vars_to_remove, DECL_UID (var)))
4948 *p = TREE_CHAIN (*p);
4952 p = &TREE_CHAIN (*p);
4956 BITMAP_FREE (vars_to_remove);
4958 /* Rewire the entry and exit blocks. The successor to the entry
4959 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4960 the child function. Similarly, the predecessor of DEST_FN's
4961 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4962 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4963 various CFG manipulation function get to the right CFG.
4965 FIXME, this is silly. The CFG ought to become a parameter to
4968 make_edge (ENTRY_BLOCK_PTR, entry_bb, EDGE_FALLTHRU);
4970 make_edge (exit_bb, EXIT_BLOCK_PTR, 0);
4973 /* Back in the original function, the SESE region has disappeared,
4974 create a new basic block in its place. */
4975 bb = create_empty_bb (entry_pred[0]);
4976 for (i = 0; i < num_entry_edges; i++)
4977 make_edge (entry_pred[i], bb, entry_flag[i]);
4979 for (i = 0; i < num_exit_edges; i++)
4980 make_edge (bb, exit_succ[i], exit_flag[i]);
4989 free_dominance_info (CDI_DOMINATORS);
4990 free_dominance_info (CDI_POST_DOMINATORS);
4991 VEC_free (basic_block, heap, bbs);
4997 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5000 dump_function_to_file (tree fn, FILE *file, int flags)
5002 tree arg, vars, var;
5003 bool ignore_topmost_bind = false, any_var = false;
5006 struct function *saved_cfun;
5008 fprintf (file, "%s (", lang_hooks.decl_printable_name (fn, 2));
5010 arg = DECL_ARGUMENTS (fn);
5013 print_generic_expr (file, arg, dump_flags);
5014 if (TREE_CHAIN (arg))
5015 fprintf (file, ", ");
5016 arg = TREE_CHAIN (arg);
5018 fprintf (file, ")\n");
5020 if (flags & TDF_DETAILS)
5021 dump_eh_tree (file, DECL_STRUCT_FUNCTION (fn));
5022 if (flags & TDF_RAW)
5024 dump_node (fn, TDF_SLIM | flags, file);
5028 /* Switch CFUN to point to FN. */
5030 cfun = DECL_STRUCT_FUNCTION (fn);
5032 /* When GIMPLE is lowered, the variables are no longer available in
5033 BIND_EXPRs, so display them separately. */
5034 if (cfun && cfun->decl == fn && cfun->unexpanded_var_list)
5036 ignore_topmost_bind = true;
5038 fprintf (file, "{\n");
5039 for (vars = cfun->unexpanded_var_list; vars; vars = TREE_CHAIN (vars))
5041 var = TREE_VALUE (vars);
5043 print_generic_decl (file, var, flags);
5044 fprintf (file, "\n");
5050 if (cfun && cfun->decl == fn && cfun->cfg && basic_block_info)
5052 /* Make a CFG based dump. */
5053 check_bb_profile (ENTRY_BLOCK_PTR, file);
5054 if (!ignore_topmost_bind)
5055 fprintf (file, "{\n");
5057 if (any_var && n_basic_blocks)
5058 fprintf (file, "\n");
5061 dump_generic_bb (file, bb, 2, flags);
5063 fprintf (file, "}\n");
5064 check_bb_profile (EXIT_BLOCK_PTR, file);
5070 /* Make a tree based dump. */
5071 chain = DECL_SAVED_TREE (fn);
5073 if (chain && TREE_CODE (chain) == BIND_EXPR)
5075 if (ignore_topmost_bind)
5077 chain = BIND_EXPR_BODY (chain);
5085 if (!ignore_topmost_bind)
5086 fprintf (file, "{\n");
5091 fprintf (file, "\n");
5093 print_generic_stmt_indented (file, chain, flags, indent);
5094 if (ignore_topmost_bind)
5095 fprintf (file, "}\n");
5098 fprintf (file, "\n\n");
5105 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5108 debug_function (tree fn, int flags)
5110 dump_function_to_file (fn, stderr, flags);
5114 /* Pretty print of the loops intermediate representation. */
5115 static void print_loop (FILE *, struct loop *, int);
5116 static void print_pred_bbs (FILE *, basic_block bb);
5117 static void print_succ_bbs (FILE *, basic_block bb);
5120 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5123 print_pred_bbs (FILE *file, basic_block bb)
5128 FOR_EACH_EDGE (e, ei, bb->preds)
5129 fprintf (file, "bb_%d ", e->src->index);
5133 /* Print on FILE the indexes for the successors of basic_block BB. */
5136 print_succ_bbs (FILE *file, basic_block bb)
5141 FOR_EACH_EDGE (e, ei, bb->succs)
5142 fprintf (file, "bb_%d ", e->dest->index);
5146 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5149 print_loop (FILE *file, struct loop *loop, int indent)
5157 s_indent = (char *) alloca ((size_t) indent + 1);
5158 memset ((void *) s_indent, ' ', (size_t) indent);
5159 s_indent[indent] = '\0';
5161 /* Print the loop's header. */
5162 fprintf (file, "%sloop_%d\n", s_indent, loop->num);
5164 /* Print the loop's body. */
5165 fprintf (file, "%s{\n", s_indent);
5167 if (bb->loop_father == loop)
5169 /* Print the basic_block's header. */
5170 fprintf (file, "%s bb_%d (preds = {", s_indent, bb->index);
5171 print_pred_bbs (file, bb);
5172 fprintf (file, "}, succs = {");
5173 print_succ_bbs (file, bb);
5174 fprintf (file, "})\n");
5176 /* Print the basic_block's body. */
5177 fprintf (file, "%s {\n", s_indent);
5178 tree_dump_bb (bb, file, indent + 4);
5179 fprintf (file, "%s }\n", s_indent);
5182 print_loop (file, loop->inner, indent + 2);
5183 fprintf (file, "%s}\n", s_indent);
5184 print_loop (file, loop->next, indent);
5188 /* Follow a CFG edge from the entry point of the program, and on entry
5189 of a loop, pretty print the loop structure on FILE. */
5192 print_loop_ir (FILE *file)
5196 bb = BASIC_BLOCK (NUM_FIXED_BLOCKS);
5197 if (bb && bb->loop_father)
5198 print_loop (file, bb->loop_father, 0);
5202 /* Debugging loops structure at tree level. */
5205 debug_loop_ir (void)
5207 print_loop_ir (stderr);
5211 /* Return true if BB ends with a call, possibly followed by some
5212 instructions that must stay with the call. Return false,
5216 tree_block_ends_with_call_p (basic_block bb)
5218 block_stmt_iterator bsi = bsi_last (bb);
5219 return get_call_expr_in (bsi_stmt (bsi)) != NULL;
5223 /* Return true if BB ends with a conditional branch. Return false,
5227 tree_block_ends_with_condjump_p (basic_block bb)
5229 tree stmt = last_stmt (bb);
5230 return (stmt && TREE_CODE (stmt) == COND_EXPR);
5234 /* Return true if we need to add fake edge to exit at statement T.
5235 Helper function for tree_flow_call_edges_add. */
5238 need_fake_edge_p (tree t)
5242 /* NORETURN and LONGJMP calls already have an edge to exit.
5243 CONST and PURE calls do not need one.
5244 We don't currently check for CONST and PURE here, although
5245 it would be a good idea, because those attributes are
5246 figured out from the RTL in mark_constant_function, and
5247 the counter incrementation code from -fprofile-arcs
5248 leads to different results from -fbranch-probabilities. */
5249 call = get_call_expr_in (t);
5251 && !(call_expr_flags (call) & ECF_NORETURN))
5254 if (TREE_CODE (t) == ASM_EXPR
5255 && (ASM_VOLATILE_P (t) || ASM_INPUT_P (t)))
5262 /* Add fake edges to the function exit for any non constant and non
5263 noreturn calls, volatile inline assembly in the bitmap of blocks
5264 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5265 the number of blocks that were split.
5267 The goal is to expose cases in which entering a basic block does
5268 not imply that all subsequent instructions must be executed. */
5271 tree_flow_call_edges_add (sbitmap blocks)
5274 int blocks_split = 0;
5275 int last_bb = last_basic_block;
5276 bool check_last_block = false;
5278 if (n_basic_blocks == NUM_FIXED_BLOCKS)
5282 check_last_block = true;
5284 check_last_block = TEST_BIT (blocks, EXIT_BLOCK_PTR->prev_bb->index);
5286 /* In the last basic block, before epilogue generation, there will be
5287 a fallthru edge to EXIT. Special care is required if the last insn
5288 of the last basic block is a call because make_edge folds duplicate
5289 edges, which would result in the fallthru edge also being marked
5290 fake, which would result in the fallthru edge being removed by
5291 remove_fake_edges, which would result in an invalid CFG.
5293 Moreover, we can't elide the outgoing fake edge, since the block
5294 profiler needs to take this into account in order to solve the minimal
5295 spanning tree in the case that the call doesn't return.
5297 Handle this by adding a dummy instruction in a new last basic block. */
5298 if (check_last_block)
5300 basic_block bb = EXIT_BLOCK_PTR->prev_bb;
5301 block_stmt_iterator bsi = bsi_last (bb);
5303 if (!bsi_end_p (bsi))
5306 if (t && need_fake_edge_p (t))
5310 e = find_edge (bb, EXIT_BLOCK_PTR);
5313 bsi_insert_on_edge (e, build_empty_stmt ());
5314 bsi_commit_edge_inserts ();
5319 /* Now add fake edges to the function exit for any non constant
5320 calls since there is no way that we can determine if they will
5322 for (i = 0; i < last_bb; i++)
5324 basic_block bb = BASIC_BLOCK (i);
5325 block_stmt_iterator bsi;
5326 tree stmt, last_stmt;
5331 if (blocks && !TEST_BIT (blocks, i))
5334 bsi = bsi_last (bb);
5335 if (!bsi_end_p (bsi))
5337 last_stmt = bsi_stmt (bsi);
5340 stmt = bsi_stmt (bsi);
5341 if (need_fake_edge_p (stmt))
5344 /* The handling above of the final block before the
5345 epilogue should be enough to verify that there is
5346 no edge to the exit block in CFG already.
5347 Calling make_edge in such case would cause us to
5348 mark that edge as fake and remove it later. */
5349 #ifdef ENABLE_CHECKING
5350 if (stmt == last_stmt)
5352 e = find_edge (bb, EXIT_BLOCK_PTR);
5353 gcc_assert (e == NULL);
5357 /* Note that the following may create a new basic block
5358 and renumber the existing basic blocks. */
5359 if (stmt != last_stmt)
5361 e = split_block (bb, stmt);
5365 make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
5369 while (!bsi_end_p (bsi));
5374 verify_flow_info ();
5376 return blocks_split;
5379 /* Purge dead abnormal call edges from basic block BB. */
5382 tree_purge_dead_abnormal_call_edges (basic_block bb)
5384 bool changed = tree_purge_dead_eh_edges (bb);
5386 if (current_function_has_nonlocal_label)
5388 tree stmt = last_stmt (bb);
5392 if (!(stmt && tree_can_make_abnormal_goto (stmt)))
5393 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5395 if (e->flags & EDGE_ABNORMAL)
5404 /* See tree_purge_dead_eh_edges below. */
5406 free_dominance_info (CDI_DOMINATORS);
5412 /* Purge dead EH edges from basic block BB. */
5415 tree_purge_dead_eh_edges (basic_block bb)
5417 bool changed = false;
5420 tree stmt = last_stmt (bb);
5422 if (stmt && tree_can_throw_internal (stmt))
5425 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
5427 if (e->flags & EDGE_EH)
5436 /* Removal of dead EH edges might change dominators of not
5437 just immediate successors. E.g. when bb1 is changed so that
5438 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5439 eh edges purged by this function in:
5451 idom(bb5) must be recomputed. For now just free the dominance
5454 free_dominance_info (CDI_DOMINATORS);
5460 tree_purge_all_dead_eh_edges (bitmap blocks)
5462 bool changed = false;
5466 EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi)
5468 changed |= tree_purge_dead_eh_edges (BASIC_BLOCK (i));
5474 /* This function is called whenever a new edge is created or
5478 tree_execute_on_growing_pred (edge e)
5480 basic_block bb = e->dest;
5483 reserve_phi_args_for_new_edge (bb);
5486 /* This function is called immediately before edge E is removed from
5487 the edge vector E->dest->preds. */
5490 tree_execute_on_shrinking_pred (edge e)
5492 if (phi_nodes (e->dest))
5493 remove_phi_args (e);
5496 /*---------------------------------------------------------------------------
5497 Helper functions for Loop versioning
5498 ---------------------------------------------------------------------------*/
5500 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5501 of 'first'. Both of them are dominated by 'new_head' basic block. When
5502 'new_head' was created by 'second's incoming edge it received phi arguments
5503 on the edge by split_edge(). Later, additional edge 'e' was created to
5504 connect 'new_head' and 'first'. Now this routine adds phi args on this
5505 additional edge 'e' that new_head to second edge received as part of edge
5510 tree_lv_adjust_loop_header_phi (basic_block first, basic_block second,
5511 basic_block new_head, edge e)
5514 edge e2 = find_edge (new_head, second);
5516 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5517 edge, we should always have an edge from NEW_HEAD to SECOND. */
5518 gcc_assert (e2 != NULL);
5520 /* Browse all 'second' basic block phi nodes and add phi args to
5521 edge 'e' for 'first' head. PHI args are always in correct order. */
5523 for (phi2 = phi_nodes (second), phi1 = phi_nodes (first);
5525 phi2 = PHI_CHAIN (phi2), phi1 = PHI_CHAIN (phi1))
5527 tree def = PHI_ARG_DEF (phi2, e2->dest_idx);
5528 add_phi_arg (phi1, def, e);
5532 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5533 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5534 the destination of the ELSE part. */
5536 tree_lv_add_condition_to_bb (basic_block first_head, basic_block second_head,
5537 basic_block cond_bb, void *cond_e)
5539 block_stmt_iterator bsi;
5540 tree goto1 = NULL_TREE;
5541 tree goto2 = NULL_TREE;
5542 tree new_cond_expr = NULL_TREE;
5543 tree cond_expr = (tree) cond_e;
5546 /* Build new conditional expr */
5547 goto1 = build1 (GOTO_EXPR, void_type_node, tree_block_label (first_head));
5548 goto2 = build1 (GOTO_EXPR, void_type_node, tree_block_label (second_head));
5549 new_cond_expr = build3 (COND_EXPR, void_type_node, cond_expr, goto1, goto2);
5551 /* Add new cond in cond_bb. */
5552 bsi = bsi_start (cond_bb);
5553 bsi_insert_after (&bsi, new_cond_expr, BSI_NEW_STMT);
5554 /* Adjust edges appropriately to connect new head with first head
5555 as well as second head. */
5556 e0 = single_succ_edge (cond_bb);
5557 e0->flags &= ~EDGE_FALLTHRU;
5558 e0->flags |= EDGE_FALSE_VALUE;
5561 struct cfg_hooks tree_cfg_hooks = {
5563 tree_verify_flow_info,
5564 tree_dump_bb, /* dump_bb */
5565 create_bb, /* create_basic_block */
5566 tree_redirect_edge_and_branch,/* redirect_edge_and_branch */
5567 tree_redirect_edge_and_branch_force,/* redirect_edge_and_branch_force */
5568 remove_bb, /* delete_basic_block */
5569 tree_split_block, /* split_block */
5570 tree_move_block_after, /* move_block_after */
5571 tree_can_merge_blocks_p, /* can_merge_blocks_p */
5572 tree_merge_blocks, /* merge_blocks */
5573 tree_predict_edge, /* predict_edge */
5574 tree_predicted_by_p, /* predicted_by_p */
5575 tree_can_duplicate_bb_p, /* can_duplicate_block_p */
5576 tree_duplicate_bb, /* duplicate_block */
5577 tree_split_edge, /* split_edge */
5578 tree_make_forwarder_block, /* make_forward_block */
5579 NULL, /* tidy_fallthru_edge */
5580 tree_block_ends_with_call_p, /* block_ends_with_call_p */
5581 tree_block_ends_with_condjump_p, /* block_ends_with_condjump_p */
5582 tree_flow_call_edges_add, /* flow_call_edges_add */
5583 tree_execute_on_growing_pred, /* execute_on_growing_pred */
5584 tree_execute_on_shrinking_pred, /* execute_on_shrinking_pred */
5585 tree_duplicate_loop_to_header_edge, /* duplicate loop for trees */
5586 tree_lv_add_condition_to_bb, /* lv_add_condition_to_bb */
5587 tree_lv_adjust_loop_header_phi, /* lv_adjust_loop_header_phi*/
5588 extract_true_false_edges_from_block, /* extract_cond_bb_edges */
5589 flush_pending_stmts /* flush_pending_stmts */
5593 /* Split all critical edges. */
5596 split_critical_edges (void)
5602 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5603 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5604 mappings around the calls to split_edge. */
5605 start_recording_case_labels ();
5608 FOR_EACH_EDGE (e, ei, bb->succs)
5609 if (EDGE_CRITICAL_P (e) && !(e->flags & EDGE_ABNORMAL))
5614 end_recording_case_labels ();
5618 struct tree_opt_pass pass_split_crit_edges =
5620 "crited", /* name */
5622 split_critical_edges, /* execute */
5625 0, /* static_pass_number */
5626 TV_TREE_SPLIT_EDGES, /* tv_id */
5627 PROP_cfg, /* properties required */
5628 PROP_no_crit_edges, /* properties_provided */
5629 0, /* properties_destroyed */
5630 0, /* todo_flags_start */
5631 TODO_dump_func, /* todo_flags_finish */
5636 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5637 a temporary, make sure and register it to be renamed if necessary,
5638 and finally return the temporary. Put the statements to compute
5639 EXP before the current statement in BSI. */
5642 gimplify_val (block_stmt_iterator *bsi, tree type, tree exp)
5644 tree t, new_stmt, orig_stmt;
5646 if (is_gimple_val (exp))
5649 t = make_rename_temp (type, NULL);
5650 new_stmt = build2 (MODIFY_EXPR, type, t, exp);
5652 orig_stmt = bsi_stmt (*bsi);
5653 SET_EXPR_LOCUS (new_stmt, EXPR_LOCUS (orig_stmt));
5654 TREE_BLOCK (new_stmt) = TREE_BLOCK (orig_stmt);
5656 bsi_insert_before (bsi, new_stmt, BSI_SAME_STMT);
5658 mark_new_vars_to_rename (new_stmt);
5663 /* Build a ternary operation and gimplify it. Emit code before BSI.
5664 Return the gimple_val holding the result. */
5667 gimplify_build3 (block_stmt_iterator *bsi, enum tree_code code,
5668 tree type, tree a, tree b, tree c)
5672 ret = fold_build3 (code, type, a, b, c);
5675 return gimplify_val (bsi, type, ret);
5678 /* Build a binary operation and gimplify it. Emit code before BSI.
5679 Return the gimple_val holding the result. */
5682 gimplify_build2 (block_stmt_iterator *bsi, enum tree_code code,
5683 tree type, tree a, tree b)
5687 ret = fold_build2 (code, type, a, b);
5690 return gimplify_val (bsi, type, ret);
5693 /* Build a unary operation and gimplify it. Emit code before BSI.
5694 Return the gimple_val holding the result. */
5697 gimplify_build1 (block_stmt_iterator *bsi, enum tree_code code, tree type,
5702 ret = fold_build1 (code, type, a);
5705 return gimplify_val (bsi, type, ret);
5710 /* Emit return warnings. */
5713 execute_warn_function_return (void)
5715 #ifdef USE_MAPPED_LOCATION
5716 source_location location;
5724 /* If we have a path to EXIT, then we do return. */
5725 if (TREE_THIS_VOLATILE (cfun->decl)
5726 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
5728 #ifdef USE_MAPPED_LOCATION
5729 location = UNKNOWN_LOCATION;
5733 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5735 last = last_stmt (e->src);
5736 if (TREE_CODE (last) == RETURN_EXPR
5737 #ifdef USE_MAPPED_LOCATION
5738 && (location = EXPR_LOCATION (last)) != UNKNOWN_LOCATION)
5740 && (locus = EXPR_LOCUS (last)) != NULL)
5744 #ifdef USE_MAPPED_LOCATION
5745 if (location == UNKNOWN_LOCATION)
5746 location = cfun->function_end_locus;
5747 warning (0, "%H%<noreturn%> function does return", &location);
5750 locus = &cfun->function_end_locus;
5751 warning (0, "%H%<noreturn%> function does return", locus);
5755 /* If we see "return;" in some basic block, then we do reach the end
5756 without returning a value. */
5757 else if (warn_return_type
5758 && !TREE_NO_WARNING (cfun->decl)
5759 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0
5760 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun->decl))))
5762 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
5764 tree last = last_stmt (e->src);
5765 if (TREE_CODE (last) == RETURN_EXPR
5766 && TREE_OPERAND (last, 0) == NULL
5767 && !TREE_NO_WARNING (last))
5769 #ifdef USE_MAPPED_LOCATION
5770 location = EXPR_LOCATION (last);
5771 if (location == UNKNOWN_LOCATION)
5772 location = cfun->function_end_locus;
5773 warning (0, "%Hcontrol reaches end of non-void function", &location);
5775 locus = EXPR_LOCUS (last);
5777 locus = &cfun->function_end_locus;
5778 warning (0, "%Hcontrol reaches end of non-void function", locus);
5780 TREE_NO_WARNING (cfun->decl) = 1;
5789 /* Given a basic block B which ends with a conditional and has
5790 precisely two successors, determine which of the edges is taken if
5791 the conditional is true and which is taken if the conditional is
5792 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5795 extract_true_false_edges_from_block (basic_block b,
5799 edge e = EDGE_SUCC (b, 0);
5801 if (e->flags & EDGE_TRUE_VALUE)
5804 *false_edge = EDGE_SUCC (b, 1);
5809 *true_edge = EDGE_SUCC (b, 1);
5813 struct tree_opt_pass pass_warn_function_return =
5817 execute_warn_function_return, /* execute */
5820 0, /* static_pass_number */
5822 PROP_cfg, /* properties_required */
5823 0, /* properties_provided */
5824 0, /* properties_destroyed */
5825 0, /* todo_flags_start */
5826 0, /* todo_flags_finish */
5830 /* Emit noreturn warnings. */
5833 execute_warn_function_noreturn (void)
5835 if (warn_missing_noreturn
5836 && !TREE_THIS_VOLATILE (cfun->decl)
5837 && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
5838 && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
5839 warning (OPT_Wmissing_noreturn, "%Jfunction might be possible candidate "
5840 "for attribute %<noreturn%>",
5845 struct tree_opt_pass pass_warn_function_noreturn =
5849 execute_warn_function_noreturn, /* execute */
5852 0, /* static_pass_number */
5854 PROP_cfg, /* properties_required */
5855 0, /* properties_provided */
5856 0, /* properties_destroyed */
5857 0, /* todo_flags_start */
5858 0, /* todo_flags_finish */