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"
49 #include "value-prof.h"
51 /* This file contains functions for building the Control Flow Graph (CFG)
52 for a function tree. */
54 /* Local declarations. */
56 /* Initial capacity for the basic block array. */
57 static const int initial_cfg_capacity
= 20;
59 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
60 which use a particular edge. The CASE_LABEL_EXPRs are chained together
61 via their TREE_CHAIN field, which we clear after we're done with the
62 hash table to prevent problems with duplication of SWITCH_EXPRs.
64 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
65 update the case vector in response to edge redirections.
67 Right now this table is set up and torn down at key points in the
68 compilation process. It would be nice if we could make the table
69 more persistent. The key is getting notification of changes to
70 the CFG (particularly edge removal, creation and redirection). */
72 struct edge_to_cases_elt
74 /* The edge itself. Necessary for hashing and equality tests. */
77 /* The case labels associated with this edge. We link these up via
78 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
79 when we destroy the hash table. This prevents problems when copying
84 static htab_t edge_to_cases
;
89 long num_merged_labels
;
92 static struct cfg_stats_d cfg_stats
;
94 /* Nonzero if we found a computed goto while building basic blocks. */
95 static bool found_computed_goto
;
97 /* Basic blocks and flowgraphs. */
98 static basic_block
create_bb (void *, void *, basic_block
);
99 static void make_blocks (tree
);
100 static void factor_computed_gotos (void);
103 static void make_edges (void);
104 static void make_cond_expr_edges (basic_block
);
105 static void make_switch_expr_edges (basic_block
);
106 static void make_goto_expr_edges (basic_block
);
107 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
108 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
109 static unsigned int split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree
, tree
);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge
);
115 static void tree_cfg2vcg (FILE *);
116 static inline void change_bb_for_stmt (tree t
, basic_block bb
);
118 /* Flowgraph optimization and cleanup. */
119 static void tree_merge_blocks (basic_block
, basic_block
);
120 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
121 static void remove_bb (basic_block
);
122 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
123 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
124 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
125 static tree
find_case_label_for_value (tree
, tree
);
128 init_empty_tree_cfg (void)
130 /* Initialize the basic block array. */
132 profile_status
= PROFILE_ABSENT
;
133 n_basic_blocks
= NUM_FIXED_BLOCKS
;
134 last_basic_block
= NUM_FIXED_BLOCKS
;
135 basic_block_info
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
136 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
,
137 initial_cfg_capacity
);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
141 VEC_safe_grow_cleared (basic_block
, gc
, label_to_block_map
,
142 initial_cfg_capacity
);
144 SET_BASIC_BLOCK (ENTRY_BLOCK
, ENTRY_BLOCK_PTR
);
145 SET_BASIC_BLOCK (EXIT_BLOCK
, EXIT_BLOCK_PTR
);
146 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
147 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
150 /*---------------------------------------------------------------------------
152 ---------------------------------------------------------------------------*/
154 /* Entry point to the CFG builder for trees. TP points to the list of
155 statements to be added to the flowgraph. */
158 build_tree_cfg (tree
*tp
)
160 /* Register specific tree functions. */
161 tree_register_cfg_hooks ();
163 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
165 init_empty_tree_cfg ();
167 found_computed_goto
= 0;
170 /* Computed gotos are hell to deal with, especially if there are
171 lots of them with a large number of destinations. So we factor
172 them to a common computed goto location before we build the
173 edge list. After we convert back to normal form, we will un-factor
174 the computed gotos since factoring introduces an unwanted jump. */
175 if (found_computed_goto
)
176 factor_computed_gotos ();
178 /* Make sure there is always at least one block, even if it's empty. */
179 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
180 create_empty_bb (ENTRY_BLOCK_PTR
);
182 /* Adjust the size of the array. */
183 if (VEC_length (basic_block
, basic_block_info
) < (size_t) n_basic_blocks
)
184 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, n_basic_blocks
);
186 /* To speed up statement iterator walks, we first purge dead labels. */
187 cleanup_dead_labels ();
189 /* Group case nodes to reduce the number of edges.
190 We do this after cleaning up dead labels because otherwise we miss
191 a lot of obvious case merging opportunities. */
192 group_case_labels ();
194 /* Create the edges of the flowgraph. */
197 /* Debugging dumps. */
199 /* Write the flowgraph to a VCG file. */
201 int local_dump_flags
;
202 FILE *vcg_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
205 tree_cfg2vcg (vcg_file
);
206 dump_end (TDI_vcg
, vcg_file
);
210 #ifdef ENABLE_CHECKING
214 /* Dump a textual representation of the flowgraph. */
216 dump_tree_cfg (dump_file
, dump_flags
);
220 execute_build_cfg (void)
222 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
226 struct tree_opt_pass pass_build_cfg
=
230 execute_build_cfg
, /* execute */
233 0, /* static_pass_number */
234 TV_TREE_CFG
, /* tv_id */
235 PROP_gimple_leh
, /* properties_required */
236 PROP_cfg
, /* properties_provided */
237 0, /* properties_destroyed */
238 0, /* todo_flags_start */
239 TODO_verify_stmts
, /* todo_flags_finish */
243 /* Search the CFG for any computed gotos. If found, factor them to a
244 common computed goto site. Also record the location of that site so
245 that we can un-factor the gotos after we have converted back to
249 factor_computed_gotos (void)
252 tree factored_label_decl
= NULL
;
254 tree factored_computed_goto_label
= NULL
;
255 tree factored_computed_goto
= NULL
;
257 /* We know there are one or more computed gotos in this function.
258 Examine the last statement in each basic block to see if the block
259 ends with a computed goto. */
263 block_stmt_iterator bsi
= bsi_last (bb
);
268 last
= bsi_stmt (bsi
);
270 /* Ignore the computed goto we create when we factor the original
272 if (last
== factored_computed_goto
)
275 /* If the last statement is a computed goto, factor it. */
276 if (computed_goto_p (last
))
280 /* The first time we find a computed goto we need to create
281 the factored goto block and the variable each original
282 computed goto will use for their goto destination. */
283 if (! factored_computed_goto
)
285 basic_block new_bb
= create_empty_bb (bb
);
286 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
288 /* Create the destination of the factored goto. Each original
289 computed goto will put its desired destination into this
290 variable and jump to the label we create immediately
292 var
= create_tmp_var (ptr_type_node
, "gotovar");
294 /* Build a label for the new block which will contain the
295 factored computed goto. */
296 factored_label_decl
= create_artificial_label ();
297 factored_computed_goto_label
298 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
299 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
302 /* Build our new computed goto. */
303 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
304 bsi_insert_after (&new_bsi
, factored_computed_goto
,
308 /* Copy the original computed goto's destination into VAR. */
309 assignment
= build2_gimple (GIMPLE_MODIFY_STMT
,
310 var
, GOTO_DESTINATION (last
));
311 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
313 /* And re-vector the computed goto to the new destination. */
314 GOTO_DESTINATION (last
) = factored_label_decl
;
320 /* Build a flowgraph for the statement_list STMT_LIST. */
323 make_blocks (tree stmt_list
)
325 tree_stmt_iterator i
= tsi_start (stmt_list
);
327 bool start_new_block
= true;
328 bool first_stmt_of_list
= true;
329 basic_block bb
= ENTRY_BLOCK_PTR
;
331 while (!tsi_end_p (i
))
338 /* If the statement starts a new basic block or if we have determined
339 in a previous pass that we need to create a new block for STMT, do
341 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
343 if (!first_stmt_of_list
)
344 stmt_list
= tsi_split_statement_list_before (&i
);
345 bb
= create_basic_block (stmt_list
, NULL
, bb
);
346 start_new_block
= false;
349 /* Now add STMT to BB and create the subgraphs for special statement
351 set_bb_for_stmt (stmt
, bb
);
353 if (computed_goto_p (stmt
))
354 found_computed_goto
= true;
356 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
358 if (stmt_ends_bb_p (stmt
))
359 start_new_block
= true;
362 first_stmt_of_list
= false;
367 /* Create and return a new empty basic block after bb AFTER. */
370 create_bb (void *h
, void *e
, basic_block after
)
376 /* Create and initialize a new basic block. Since alloc_block uses
377 ggc_alloc_cleared to allocate a basic block, we do not have to
378 clear the newly allocated basic block here. */
381 bb
->index
= last_basic_block
;
383 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
385 /* Add the new block to the linked list of blocks. */
386 link_block (bb
, after
);
388 /* Grow the basic block array if needed. */
389 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
391 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
392 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, new_size
);
395 /* Add the newly created block to the array. */
396 SET_BASIC_BLOCK (last_basic_block
, bb
);
405 /*---------------------------------------------------------------------------
407 ---------------------------------------------------------------------------*/
409 /* Fold COND_EXPR_COND of each COND_EXPR. */
412 fold_cond_expr_cond (void)
418 tree stmt
= last_stmt (bb
);
421 && TREE_CODE (stmt
) == COND_EXPR
)
423 tree cond
= fold (COND_EXPR_COND (stmt
));
424 if (integer_zerop (cond
))
425 COND_EXPR_COND (stmt
) = boolean_false_node
;
426 else if (integer_onep (cond
))
427 COND_EXPR_COND (stmt
) = boolean_true_node
;
432 /* Join all the blocks in the flowgraph. */
438 struct omp_region
*cur_region
= NULL
;
440 /* Create an edge from entry to the first block with executable
442 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
444 /* Traverse the basic block array placing edges. */
447 tree last
= last_stmt (bb
);
452 enum tree_code code
= TREE_CODE (last
);
456 make_goto_expr_edges (bb
);
460 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
464 make_cond_expr_edges (bb
);
468 make_switch_expr_edges (bb
);
472 make_eh_edges (last
);
477 /* If this function receives a nonlocal goto, then we need to
478 make edges from this call site to all the nonlocal goto
480 if (tree_can_make_abnormal_goto (last
))
481 make_abnormal_goto_edges (bb
, true);
483 /* If this statement has reachable exception handlers, then
484 create abnormal edges to them. */
485 make_eh_edges (last
);
487 /* Some calls are known not to return. */
488 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
494 case GIMPLE_MODIFY_STMT
:
495 if (is_ctrl_altering_stmt (last
))
497 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
498 the CALL_EXPR may have an abnormal edge. Search the RHS
499 for this case and create any required edges. */
500 if (tree_can_make_abnormal_goto (last
))
501 make_abnormal_goto_edges (bb
, true);
503 make_eh_edges (last
);
515 cur_region
= new_omp_region (bb
, code
, cur_region
);
520 cur_region
= new_omp_region (bb
, code
, cur_region
);
525 /* In the case of an OMP_SECTION, the edge will go somewhere
526 other than the next block. This will be created later. */
527 cur_region
->exit
= bb
;
528 fallthru
= cur_region
->type
!= OMP_SECTION
;
529 cur_region
= cur_region
->outer
;
533 cur_region
->cont
= bb
;
534 switch (cur_region
->type
)
537 /* ??? Technically there should be a some sort of loopback
538 edge here, but it goes to a block that doesn't exist yet,
539 and without it, updating the ssa form would be a real
540 bear. Fortunately, we don't yet do ssa before expanding
545 /* Wire up the edges into and out of the nested sections. */
546 /* ??? Similarly wrt loopback. */
548 struct omp_region
*i
;
549 for (i
= cur_region
->inner
; i
; i
= i
->next
)
551 gcc_assert (i
->type
== OMP_SECTION
);
552 make_edge (cur_region
->entry
, i
->entry
, 0);
553 make_edge (i
->exit
, bb
, EDGE_FALLTHRU
);
565 gcc_assert (!stmt_ends_bb_p (last
));
573 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
579 /* Fold COND_EXPR_COND of each COND_EXPR. */
580 fold_cond_expr_cond ();
582 /* Clean up the graph and warn for unreachable code. */
587 /* Create the edges for a COND_EXPR starting at block BB.
588 At this point, both clauses must contain only simple gotos. */
591 make_cond_expr_edges (basic_block bb
)
593 tree entry
= last_stmt (bb
);
594 basic_block then_bb
, else_bb
;
595 tree then_label
, else_label
;
599 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
601 /* Entry basic blocks for each component. */
602 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
603 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
604 then_bb
= label_to_block (then_label
);
605 else_bb
= label_to_block (else_label
);
607 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
608 #ifdef USE_MAPPED_LOCATION
609 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
611 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
613 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
616 #ifdef USE_MAPPED_LOCATION
617 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
619 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
624 /* Hashing routine for EDGE_TO_CASES. */
627 edge_to_cases_hash (const void *p
)
629 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
631 /* Hash on the edge itself (which is a pointer). */
632 return htab_hash_pointer (e
);
635 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
636 for equality is just a pointer comparison. */
639 edge_to_cases_eq (const void *p1
, const void *p2
)
641 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
642 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
647 /* Called for each element in the hash table (P) as we delete the
648 edge to cases hash table.
650 Clear all the TREE_CHAINs to prevent problems with copying of
651 SWITCH_EXPRs and structure sharing rules, then free the hash table
655 edge_to_cases_cleanup (void *p
)
657 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
660 for (t
= elt
->case_labels
; t
; t
= next
)
662 next
= TREE_CHAIN (t
);
663 TREE_CHAIN (t
) = NULL
;
668 /* Start recording information mapping edges to case labels. */
671 start_recording_case_labels (void)
673 gcc_assert (edge_to_cases
== NULL
);
675 edge_to_cases
= htab_create (37,
678 edge_to_cases_cleanup
);
681 /* Return nonzero if we are recording information for case labels. */
684 recording_case_labels_p (void)
686 return (edge_to_cases
!= NULL
);
689 /* Stop recording information mapping edges to case labels and
690 remove any information we have recorded. */
692 end_recording_case_labels (void)
694 htab_delete (edge_to_cases
);
695 edge_to_cases
= NULL
;
698 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
701 record_switch_edge (edge e
, tree case_label
)
703 struct edge_to_cases_elt
*elt
;
706 /* Build a hash table element so we can see if E is already
708 elt
= XNEW (struct edge_to_cases_elt
);
710 elt
->case_labels
= case_label
;
712 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
716 /* E was not in the hash table. Install E into the hash table. */
721 /* E was already in the hash table. Free ELT as we do not need it
725 /* Get the entry stored in the hash table. */
726 elt
= (struct edge_to_cases_elt
*) *slot
;
728 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
729 TREE_CHAIN (case_label
) = elt
->case_labels
;
730 elt
->case_labels
= case_label
;
734 /* If we are inside a {start,end}_recording_cases block, then return
735 a chain of CASE_LABEL_EXPRs from T which reference E.
737 Otherwise return NULL. */
740 get_cases_for_edge (edge e
, tree t
)
742 struct edge_to_cases_elt elt
, *elt_p
;
747 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
748 chains available. Return NULL so the caller can detect this case. */
749 if (!recording_case_labels_p ())
754 elt
.case_labels
= NULL
;
755 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
759 elt_p
= (struct edge_to_cases_elt
*)*slot
;
760 return elt_p
->case_labels
;
763 /* If we did not find E in the hash table, then this must be the first
764 time we have been queried for information about E & T. Add all the
765 elements from T to the hash table then perform the query again. */
767 vec
= SWITCH_LABELS (t
);
768 n
= TREE_VEC_LENGTH (vec
);
769 for (i
= 0; i
< n
; i
++)
771 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
772 basic_block label_bb
= label_to_block (lab
);
773 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
778 /* Create the edges for a SWITCH_EXPR starting at block BB.
779 At this point, the switch body has been lowered and the
780 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
783 make_switch_expr_edges (basic_block bb
)
785 tree entry
= last_stmt (bb
);
789 vec
= SWITCH_LABELS (entry
);
790 n
= TREE_VEC_LENGTH (vec
);
792 for (i
= 0; i
< n
; ++i
)
794 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
795 basic_block label_bb
= label_to_block (lab
);
796 make_edge (bb
, label_bb
, 0);
801 /* Return the basic block holding label DEST. */
804 label_to_block_fn (struct function
*ifun
, tree dest
)
806 int uid
= LABEL_DECL_UID (dest
);
808 /* We would die hard when faced by an undefined label. Emit a label to
809 the very first basic block. This will hopefully make even the dataflow
810 and undefined variable warnings quite right. */
811 if ((errorcount
|| sorrycount
) && uid
< 0)
813 block_stmt_iterator bsi
=
814 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
817 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
818 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
819 uid
= LABEL_DECL_UID (dest
);
821 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
822 <= (unsigned int) uid
)
824 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
827 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
828 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
831 make_abnormal_goto_edges (basic_block bb
, bool for_call
)
833 basic_block target_bb
;
834 block_stmt_iterator bsi
;
836 FOR_EACH_BB (target_bb
)
837 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
839 tree target
= bsi_stmt (bsi
);
841 if (TREE_CODE (target
) != LABEL_EXPR
)
844 target
= LABEL_EXPR_LABEL (target
);
846 /* Make an edge to every label block that has been marked as a
847 potential target for a computed goto or a non-local goto. */
848 if ((FORCED_LABEL (target
) && !for_call
)
849 || (DECL_NONLOCAL (target
) && for_call
))
851 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
857 /* Create edges for a goto statement at block BB. */
860 make_goto_expr_edges (basic_block bb
)
862 block_stmt_iterator last
= bsi_last (bb
);
863 tree goto_t
= bsi_stmt (last
);
865 /* A simple GOTO creates normal edges. */
866 if (simple_goto_p (goto_t
))
868 tree dest
= GOTO_DESTINATION (goto_t
);
869 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
870 #ifdef USE_MAPPED_LOCATION
871 e
->goto_locus
= EXPR_LOCATION (goto_t
);
873 e
->goto_locus
= EXPR_LOCUS (goto_t
);
875 bsi_remove (&last
, true);
879 /* A computed GOTO creates abnormal edges. */
880 make_abnormal_goto_edges (bb
, false);
884 /*---------------------------------------------------------------------------
886 ---------------------------------------------------------------------------*/
888 /* Cleanup useless labels in basic blocks. This is something we wish
889 to do early because it allows us to group case labels before creating
890 the edges for the CFG, and it speeds up block statement iterators in
892 We only run this pass once, running it more than once is probably not
895 /* A map from basic block index to the leading label of that block. */
896 static tree
*label_for_bb
;
898 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
900 update_eh_label (struct eh_region
*region
)
902 tree old_label
= get_eh_region_tree_label (region
);
906 basic_block bb
= label_to_block (old_label
);
908 /* ??? After optimizing, there may be EH regions with labels
909 that have already been removed from the function body, so
910 there is no basic block for them. */
914 new_label
= label_for_bb
[bb
->index
];
915 set_eh_region_tree_label (region
, new_label
);
919 /* Given LABEL return the first label in the same basic block. */
921 main_block_label (tree label
)
923 basic_block bb
= label_to_block (label
);
925 /* label_to_block possibly inserted undefined label into the chain. */
926 if (!label_for_bb
[bb
->index
])
927 label_for_bb
[bb
->index
] = label
;
928 return label_for_bb
[bb
->index
];
931 /* Cleanup redundant labels. This is a three-step process:
932 1) Find the leading label for each block.
933 2) Redirect all references to labels to the leading labels.
934 3) Cleanup all useless labels. */
937 cleanup_dead_labels (void)
940 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
942 /* Find a suitable label for each block. We use the first user-defined
943 label if there is one, or otherwise just the first label we see. */
946 block_stmt_iterator i
;
948 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
950 tree label
, stmt
= bsi_stmt (i
);
952 if (TREE_CODE (stmt
) != LABEL_EXPR
)
955 label
= LABEL_EXPR_LABEL (stmt
);
957 /* If we have not yet seen a label for the current block,
958 remember this one and see if there are more labels. */
959 if (! label_for_bb
[bb
->index
])
961 label_for_bb
[bb
->index
] = label
;
965 /* If we did see a label for the current block already, but it
966 is an artificially created label, replace it if the current
967 label is a user defined label. */
968 if (! DECL_ARTIFICIAL (label
)
969 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
971 label_for_bb
[bb
->index
] = label
;
977 /* Now redirect all jumps/branches to the selected label.
978 First do so for each block ending in a control statement. */
981 tree stmt
= last_stmt (bb
);
985 switch (TREE_CODE (stmt
))
989 tree true_branch
, false_branch
;
991 true_branch
= COND_EXPR_THEN (stmt
);
992 false_branch
= COND_EXPR_ELSE (stmt
);
994 GOTO_DESTINATION (true_branch
)
995 = main_block_label (GOTO_DESTINATION (true_branch
));
996 GOTO_DESTINATION (false_branch
)
997 = main_block_label (GOTO_DESTINATION (false_branch
));
1005 tree vec
= SWITCH_LABELS (stmt
);
1006 size_t n
= TREE_VEC_LENGTH (vec
);
1008 /* Replace all destination labels. */
1009 for (i
= 0; i
< n
; ++i
)
1011 tree elt
= TREE_VEC_ELT (vec
, i
);
1012 tree label
= main_block_label (CASE_LABEL (elt
));
1013 CASE_LABEL (elt
) = label
;
1018 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1019 remove them until after we've created the CFG edges. */
1021 if (! computed_goto_p (stmt
))
1023 GOTO_DESTINATION (stmt
)
1024 = main_block_label (GOTO_DESTINATION (stmt
));
1033 for_each_eh_region (update_eh_label
);
1035 /* Finally, purge dead labels. All user-defined labels and labels that
1036 can be the target of non-local gotos and labels which have their
1037 address taken are preserved. */
1040 block_stmt_iterator i
;
1041 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1043 if (! label_for_this_bb
)
1046 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1048 tree label
, stmt
= bsi_stmt (i
);
1050 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1053 label
= LABEL_EXPR_LABEL (stmt
);
1055 if (label
== label_for_this_bb
1056 || ! DECL_ARTIFICIAL (label
)
1057 || DECL_NONLOCAL (label
)
1058 || FORCED_LABEL (label
))
1061 bsi_remove (&i
, true);
1065 free (label_for_bb
);
1068 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1069 and scan the sorted vector of cases. Combine the ones jumping to the
1071 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1074 group_case_labels (void)
1080 tree stmt
= last_stmt (bb
);
1081 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1083 tree labels
= SWITCH_LABELS (stmt
);
1084 int old_size
= TREE_VEC_LENGTH (labels
);
1085 int i
, j
, new_size
= old_size
;
1086 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1089 /* The default label is always the last case in a switch
1090 statement after gimplification. */
1091 default_label
= CASE_LABEL (default_case
);
1093 /* Look for possible opportunities to merge cases.
1094 Ignore the last element of the label vector because it
1095 must be the default case. */
1097 while (i
< old_size
- 1)
1099 tree base_case
, base_label
, base_high
;
1100 base_case
= TREE_VEC_ELT (labels
, i
);
1102 gcc_assert (base_case
);
1103 base_label
= CASE_LABEL (base_case
);
1105 /* Discard cases that have the same destination as the
1107 if (base_label
== default_label
)
1109 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1115 base_high
= CASE_HIGH (base_case
) ?
1116 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1118 /* Try to merge case labels. Break out when we reach the end
1119 of the label vector or when we cannot merge the next case
1120 label with the current one. */
1121 while (i
< old_size
- 1)
1123 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1124 tree merge_label
= CASE_LABEL (merge_case
);
1125 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1126 integer_one_node
, 1);
1128 /* Merge the cases if they jump to the same place,
1129 and their ranges are consecutive. */
1130 if (merge_label
== base_label
1131 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1133 base_high
= CASE_HIGH (merge_case
) ?
1134 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1135 CASE_HIGH (base_case
) = base_high
;
1136 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1145 /* Compress the case labels in the label vector, and adjust the
1146 length of the vector. */
1147 for (i
= 0, j
= 0; i
< new_size
; i
++)
1149 while (! TREE_VEC_ELT (labels
, j
))
1151 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1153 TREE_VEC_LENGTH (labels
) = new_size
;
1158 /* Checks whether we can merge block B into block A. */
1161 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1164 block_stmt_iterator bsi
;
1167 if (!single_succ_p (a
))
1170 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1173 if (single_succ (a
) != b
)
1176 if (!single_pred_p (b
))
1179 if (b
== EXIT_BLOCK_PTR
)
1182 /* If A ends by a statement causing exceptions or something similar, we
1183 cannot merge the blocks. */
1184 stmt
= last_stmt (a
);
1185 if (stmt
&& stmt_ends_bb_p (stmt
))
1188 /* Do not allow a block with only a non-local label to be merged. */
1189 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1190 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1193 /* It must be possible to eliminate all phi nodes in B. If ssa form
1194 is not up-to-date, we cannot eliminate any phis; however, if only
1195 some symbols as whole are marked for renaming, this is not a problem,
1196 as phi nodes for those symbols are irrelevant in updating anyway. */
1197 phi
= phi_nodes (b
);
1200 if (name_mappings_registered_p ())
1203 for (; phi
; phi
= PHI_CHAIN (phi
))
1204 if (!is_gimple_reg (PHI_RESULT (phi
))
1205 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1209 /* Do not remove user labels. */
1210 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1212 stmt
= bsi_stmt (bsi
);
1213 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1215 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1219 /* Protect the loop latches. */
1221 && b
->loop_father
->latch
== b
)
1227 /* Replaces all uses of NAME by VAL. */
1230 replace_uses_by (tree name
, tree val
)
1232 imm_use_iterator imm_iter
;
1237 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, name
)
1239 if (TREE_CODE (stmt
) != PHI_NODE
)
1240 push_stmt_changes (&stmt
);
1242 FOR_EACH_IMM_USE_ON_STMT (use
, imm_iter
)
1244 replace_exp (use
, val
);
1246 if (TREE_CODE (stmt
) == PHI_NODE
)
1248 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1249 if (e
->flags
& EDGE_ABNORMAL
)
1251 /* This can only occur for virtual operands, since
1252 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1253 would prevent replacement. */
1254 gcc_assert (!is_gimple_reg (name
));
1255 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1260 if (TREE_CODE (stmt
) != PHI_NODE
)
1264 fold_stmt_inplace (stmt
);
1266 /* FIXME. This should go in pop_stmt_changes. */
1267 rhs
= get_rhs (stmt
);
1268 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1269 recompute_tree_invariant_for_addr_expr (rhs
);
1271 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1273 pop_stmt_changes (&stmt
);
1277 gcc_assert (zero_imm_uses_p (name
));
1279 /* Also update the trees stored in loop structures. */
1285 FOR_EACH_LOOP (li
, loop
, 0)
1287 substitute_in_loop_info (loop
, name
, val
);
1292 /* Merge block B into block A. */
1295 tree_merge_blocks (basic_block a
, basic_block b
)
1297 block_stmt_iterator bsi
;
1298 tree_stmt_iterator last
;
1302 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1304 /* Remove all single-valued PHI nodes from block B of the form
1305 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1307 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1309 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1311 bool may_replace_uses
= may_propagate_copy (def
, use
);
1313 /* In case we have loops to care about, do not propagate arguments of
1314 loop closed ssa phi nodes. */
1316 && is_gimple_reg (def
)
1317 && TREE_CODE (use
) == SSA_NAME
1318 && a
->loop_father
!= b
->loop_father
)
1319 may_replace_uses
= false;
1321 if (!may_replace_uses
)
1323 gcc_assert (is_gimple_reg (def
));
1325 /* Note that just emitting the copies is fine -- there is no problem
1326 with ordering of phi nodes. This is because A is the single
1327 predecessor of B, therefore results of the phi nodes cannot
1328 appear as arguments of the phi nodes. */
1329 copy
= build2_gimple (GIMPLE_MODIFY_STMT
, def
, use
);
1330 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1331 SSA_NAME_DEF_STMT (def
) = copy
;
1334 replace_uses_by (def
, use
);
1336 remove_phi_node (phi
, NULL
, false);
1339 /* Ensure that B follows A. */
1340 move_block_after (b
, a
);
1342 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1343 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1345 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1346 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1348 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1350 tree label
= bsi_stmt (bsi
);
1352 bsi_remove (&bsi
, false);
1353 /* Now that we can thread computed gotos, we might have
1354 a situation where we have a forced label in block B
1355 However, the label at the start of block B might still be
1356 used in other ways (think about the runtime checking for
1357 Fortran assigned gotos). So we can not just delete the
1358 label. Instead we move the label to the start of block A. */
1359 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1361 block_stmt_iterator dest_bsi
= bsi_start (a
);
1362 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1367 change_bb_for_stmt (bsi_stmt (bsi
), a
);
1372 /* Merge the chains. */
1373 last
= tsi_last (a
->stmt_list
);
1374 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1375 b
->stmt_list
= NULL
;
1379 /* Return the one of two successors of BB that is not reachable by a
1380 reached by a complex edge, if there is one. Else, return BB. We use
1381 this in optimizations that use post-dominators for their heuristics,
1382 to catch the cases in C++ where function calls are involved. */
1385 single_noncomplex_succ (basic_block bb
)
1388 if (EDGE_COUNT (bb
->succs
) != 2)
1391 e0
= EDGE_SUCC (bb
, 0);
1392 e1
= EDGE_SUCC (bb
, 1);
1393 if (e0
->flags
& EDGE_COMPLEX
)
1395 if (e1
->flags
& EDGE_COMPLEX
)
1402 /* Walk the function tree removing unnecessary statements.
1404 * Empty statement nodes are removed
1406 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1408 * Unnecessary COND_EXPRs are removed
1410 * Some unnecessary BIND_EXPRs are removed
1412 Clearly more work could be done. The trick is doing the analysis
1413 and removal fast enough to be a net improvement in compile times.
1415 Note that when we remove a control structure such as a COND_EXPR
1416 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1417 to ensure we eliminate all the useless code. */
1428 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1431 remove_useless_stmts_warn_notreached (tree stmt
)
1433 if (EXPR_HAS_LOCATION (stmt
))
1435 location_t loc
= EXPR_LOCATION (stmt
);
1436 if (LOCATION_LINE (loc
) > 0)
1438 warning (0, "%Hwill never be executed", &loc
);
1443 switch (TREE_CODE (stmt
))
1445 case STATEMENT_LIST
:
1447 tree_stmt_iterator i
;
1448 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1449 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1455 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1457 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1459 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1463 case TRY_FINALLY_EXPR
:
1464 case TRY_CATCH_EXPR
:
1465 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1467 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1472 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1473 case EH_FILTER_EXPR
:
1474 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1476 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1479 /* Not a live container. */
1487 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1489 tree then_clause
, else_clause
, cond
;
1490 bool save_has_label
, then_has_label
, else_has_label
;
1492 save_has_label
= data
->has_label
;
1493 data
->has_label
= false;
1494 data
->last_goto
= NULL
;
1496 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1498 then_has_label
= data
->has_label
;
1499 data
->has_label
= false;
1500 data
->last_goto
= NULL
;
1502 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1504 else_has_label
= data
->has_label
;
1505 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1507 then_clause
= COND_EXPR_THEN (*stmt_p
);
1508 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1509 cond
= fold (COND_EXPR_COND (*stmt_p
));
1511 /* If neither arm does anything at all, we can remove the whole IF. */
1512 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1514 *stmt_p
= build_empty_stmt ();
1515 data
->repeat
= true;
1518 /* If there are no reachable statements in an arm, then we can
1519 zap the entire conditional. */
1520 else if (integer_nonzerop (cond
) && !else_has_label
)
1522 if (warn_notreached
)
1523 remove_useless_stmts_warn_notreached (else_clause
);
1524 *stmt_p
= then_clause
;
1525 data
->repeat
= true;
1527 else if (integer_zerop (cond
) && !then_has_label
)
1529 if (warn_notreached
)
1530 remove_useless_stmts_warn_notreached (then_clause
);
1531 *stmt_p
= else_clause
;
1532 data
->repeat
= true;
1535 /* Check a couple of simple things on then/else with single stmts. */
1538 tree then_stmt
= expr_only (then_clause
);
1539 tree else_stmt
= expr_only (else_clause
);
1541 /* Notice branches to a common destination. */
1542 if (then_stmt
&& else_stmt
1543 && TREE_CODE (then_stmt
) == GOTO_EXPR
1544 && TREE_CODE (else_stmt
) == GOTO_EXPR
1545 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1547 *stmt_p
= then_stmt
;
1548 data
->repeat
= true;
1551 /* If the THEN/ELSE clause merely assigns a value to a variable or
1552 parameter which is already known to contain that value, then
1553 remove the useless THEN/ELSE clause. */
1554 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1557 && TREE_CODE (else_stmt
) == GIMPLE_MODIFY_STMT
1558 && GIMPLE_STMT_OPERAND (else_stmt
, 0) == cond
1559 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt
, 1)))
1560 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1562 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1563 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1564 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1565 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1567 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1568 ? then_stmt
: else_stmt
);
1569 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1570 ? &COND_EXPR_THEN (*stmt_p
)
1571 : &COND_EXPR_ELSE (*stmt_p
));
1574 && TREE_CODE (stmt
) == GIMPLE_MODIFY_STMT
1575 && GIMPLE_STMT_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1576 && GIMPLE_STMT_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1577 *location
= alloc_stmt_list ();
1581 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1582 would be re-introduced during lowering. */
1583 data
->last_goto
= NULL
;
1588 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1590 bool save_may_branch
, save_may_throw
;
1591 bool this_may_branch
, this_may_throw
;
1593 /* Collect may_branch and may_throw information for the body only. */
1594 save_may_branch
= data
->may_branch
;
1595 save_may_throw
= data
->may_throw
;
1596 data
->may_branch
= false;
1597 data
->may_throw
= false;
1598 data
->last_goto
= NULL
;
1600 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1602 this_may_branch
= data
->may_branch
;
1603 this_may_throw
= data
->may_throw
;
1604 data
->may_branch
|= save_may_branch
;
1605 data
->may_throw
|= save_may_throw
;
1606 data
->last_goto
= NULL
;
1608 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1610 /* If the body is empty, then we can emit the FINALLY block without
1611 the enclosing TRY_FINALLY_EXPR. */
1612 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1614 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1615 data
->repeat
= true;
1618 /* If the handler is empty, then we can emit the TRY block without
1619 the enclosing TRY_FINALLY_EXPR. */
1620 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1622 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1623 data
->repeat
= true;
1626 /* If the body neither throws, nor branches, then we can safely
1627 string the TRY and FINALLY blocks together. */
1628 else if (!this_may_branch
&& !this_may_throw
)
1630 tree stmt
= *stmt_p
;
1631 *stmt_p
= TREE_OPERAND (stmt
, 0);
1632 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1633 data
->repeat
= true;
1639 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1641 bool save_may_throw
, this_may_throw
;
1642 tree_stmt_iterator i
;
1645 /* Collect may_throw information for the body only. */
1646 save_may_throw
= data
->may_throw
;
1647 data
->may_throw
= false;
1648 data
->last_goto
= NULL
;
1650 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1652 this_may_throw
= data
->may_throw
;
1653 data
->may_throw
= save_may_throw
;
1655 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1656 if (!this_may_throw
)
1658 if (warn_notreached
)
1659 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1660 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1661 data
->repeat
= true;
1665 /* Process the catch clause specially. We may be able to tell that
1666 no exceptions propagate past this point. */
1668 this_may_throw
= true;
1669 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1670 stmt
= tsi_stmt (i
);
1671 data
->last_goto
= NULL
;
1673 switch (TREE_CODE (stmt
))
1676 for (; !tsi_end_p (i
); tsi_next (&i
))
1678 stmt
= tsi_stmt (i
);
1679 /* If we catch all exceptions, then the body does not
1680 propagate exceptions past this point. */
1681 if (CATCH_TYPES (stmt
) == NULL
)
1682 this_may_throw
= false;
1683 data
->last_goto
= NULL
;
1684 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1688 case EH_FILTER_EXPR
:
1689 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1690 this_may_throw
= false;
1691 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1692 this_may_throw
= false;
1693 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1697 /* Otherwise this is a cleanup. */
1698 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1700 /* If the cleanup is empty, then we can emit the TRY block without
1701 the enclosing TRY_CATCH_EXPR. */
1702 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1704 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1705 data
->repeat
= true;
1709 data
->may_throw
|= this_may_throw
;
1714 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1718 /* First remove anything underneath the BIND_EXPR. */
1719 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1721 /* If the BIND_EXPR has no variables, then we can pull everything
1722 up one level and remove the BIND_EXPR, unless this is the toplevel
1723 BIND_EXPR for the current function or an inlined function.
1725 When this situation occurs we will want to apply this
1726 optimization again. */
1727 block
= BIND_EXPR_BLOCK (*stmt_p
);
1728 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1729 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1731 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1732 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1735 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1736 data
->repeat
= true;
1742 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1744 tree dest
= GOTO_DESTINATION (*stmt_p
);
1746 data
->may_branch
= true;
1747 data
->last_goto
= NULL
;
1749 /* Record the last goto expr, so that we can delete it if unnecessary. */
1750 if (TREE_CODE (dest
) == LABEL_DECL
)
1751 data
->last_goto
= stmt_p
;
1756 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1758 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1760 data
->has_label
= true;
1762 /* We do want to jump across non-local label receiver code. */
1763 if (DECL_NONLOCAL (label
))
1764 data
->last_goto
= NULL
;
1766 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1768 *data
->last_goto
= build_empty_stmt ();
1769 data
->repeat
= true;
1772 /* ??? Add something here to delete unused labels. */
1776 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1777 decl. This allows us to eliminate redundant or useless
1778 calls to "const" functions.
1780 Gimplifier already does the same operation, but we may notice functions
1781 being const and pure once their calls has been gimplified, so we need
1782 to update the flag. */
1785 update_call_expr_flags (tree call
)
1787 tree decl
= get_callee_fndecl (call
);
1790 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1791 TREE_SIDE_EFFECTS (call
) = 0;
1792 if (TREE_NOTHROW (decl
))
1793 TREE_NOTHROW (call
) = 1;
1797 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1800 notice_special_calls (tree t
)
1802 int flags
= call_expr_flags (t
);
1804 if (flags
& ECF_MAY_BE_ALLOCA
)
1805 current_function_calls_alloca
= true;
1806 if (flags
& ECF_RETURNS_TWICE
)
1807 current_function_calls_setjmp
= true;
1811 /* Clear flags set by notice_special_calls. Used by dead code removal
1812 to update the flags. */
1815 clear_special_calls (void)
1817 current_function_calls_alloca
= false;
1818 current_function_calls_setjmp
= false;
1823 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1827 switch (TREE_CODE (t
))
1830 remove_useless_stmts_cond (tp
, data
);
1833 case TRY_FINALLY_EXPR
:
1834 remove_useless_stmts_tf (tp
, data
);
1837 case TRY_CATCH_EXPR
:
1838 remove_useless_stmts_tc (tp
, data
);
1842 remove_useless_stmts_bind (tp
, data
);
1846 remove_useless_stmts_goto (tp
, data
);
1850 remove_useless_stmts_label (tp
, data
);
1855 data
->last_goto
= NULL
;
1856 data
->may_branch
= true;
1861 data
->last_goto
= NULL
;
1862 notice_special_calls (t
);
1863 update_call_expr_flags (t
);
1864 if (tree_could_throw_p (t
))
1865 data
->may_throw
= true;
1871 case GIMPLE_MODIFY_STMT
:
1872 data
->last_goto
= NULL
;
1874 op
= get_call_expr_in (t
);
1877 update_call_expr_flags (op
);
1878 notice_special_calls (op
);
1880 if (tree_could_throw_p (t
))
1881 data
->may_throw
= true;
1884 case STATEMENT_LIST
:
1886 tree_stmt_iterator i
= tsi_start (t
);
1887 while (!tsi_end_p (i
))
1890 if (IS_EMPTY_STMT (t
))
1896 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1899 if (TREE_CODE (t
) == STATEMENT_LIST
)
1901 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1911 data
->last_goto
= NULL
;
1915 data
->last_goto
= NULL
;
1921 remove_useless_stmts (void)
1923 struct rus_data data
;
1925 clear_special_calls ();
1929 memset (&data
, 0, sizeof (data
));
1930 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1932 while (data
.repeat
);
1937 struct tree_opt_pass pass_remove_useless_stmts
=
1939 "useless", /* name */
1941 remove_useless_stmts
, /* execute */
1944 0, /* static_pass_number */
1946 PROP_gimple_any
, /* properties_required */
1947 0, /* properties_provided */
1948 0, /* properties_destroyed */
1949 0, /* todo_flags_start */
1950 TODO_dump_func
, /* todo_flags_finish */
1954 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1957 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1961 /* Since this block is no longer reachable, we can just delete all
1962 of its PHI nodes. */
1963 phi
= phi_nodes (bb
);
1966 tree next
= PHI_CHAIN (phi
);
1967 remove_phi_node (phi
, NULL_TREE
, true);
1971 /* Remove edges to BB's successors. */
1972 while (EDGE_COUNT (bb
->succs
) > 0)
1973 remove_edge (EDGE_SUCC (bb
, 0));
1977 /* Remove statements of basic block BB. */
1980 remove_bb (basic_block bb
)
1982 block_stmt_iterator i
;
1983 #ifdef USE_MAPPED_LOCATION
1984 source_location loc
= UNKNOWN_LOCATION
;
1986 source_locus loc
= 0;
1991 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1992 if (dump_flags
& TDF_DETAILS
)
1994 dump_bb (bb
, dump_file
, 0);
1995 fprintf (dump_file
, "\n");
2001 struct loop
*loop
= bb
->loop_father
;
2003 /* If a loop gets removed, clean up the information associated
2005 if (loop
->latch
== bb
2006 || loop
->header
== bb
)
2007 free_numbers_of_iterations_estimates_loop (loop
);
2010 /* Remove all the instructions in the block. */
2011 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2013 tree stmt
= bsi_stmt (i
);
2014 if (TREE_CODE (stmt
) == LABEL_EXPR
2015 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2016 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2019 block_stmt_iterator new_bsi
;
2021 /* A non-reachable non-local label may still be referenced.
2022 But it no longer needs to carry the extra semantics of
2024 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2026 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2027 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2030 new_bb
= bb
->prev_bb
;
2031 new_bsi
= bsi_start (new_bb
);
2032 bsi_remove (&i
, false);
2033 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2037 /* Release SSA definitions if we are in SSA. Note that we
2038 may be called when not in SSA. For example,
2039 final_cleanup calls this function via
2040 cleanup_tree_cfg. */
2041 if (gimple_in_ssa_p (cfun
))
2042 release_defs (stmt
);
2044 bsi_remove (&i
, true);
2047 /* Don't warn for removed gotos. Gotos are often removed due to
2048 jump threading, thus resulting in bogus warnings. Not great,
2049 since this way we lose warnings for gotos in the original
2050 program that are indeed unreachable. */
2051 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2053 #ifdef USE_MAPPED_LOCATION
2054 if (EXPR_HAS_LOCATION (stmt
))
2055 loc
= EXPR_LOCATION (stmt
);
2058 t
= EXPR_LOCUS (stmt
);
2059 if (t
&& LOCATION_LINE (*t
) > 0)
2065 /* If requested, give a warning that the first statement in the
2066 block is unreachable. We walk statements backwards in the
2067 loop above, so the last statement we process is the first statement
2069 #ifdef USE_MAPPED_LOCATION
2070 if (loc
> BUILTINS_LOCATION
)
2071 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2074 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2077 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2081 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2082 predicate VAL, return the edge that will be taken out of the block.
2083 If VAL does not match a unique edge, NULL is returned. */
2086 find_taken_edge (basic_block bb
, tree val
)
2090 stmt
= last_stmt (bb
);
2093 gcc_assert (is_ctrl_stmt (stmt
));
2096 if (! is_gimple_min_invariant (val
))
2099 if (TREE_CODE (stmt
) == COND_EXPR
)
2100 return find_taken_edge_cond_expr (bb
, val
);
2102 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2103 return find_taken_edge_switch_expr (bb
, val
);
2105 if (computed_goto_p (stmt
))
2106 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2111 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2112 statement, determine which of the outgoing edges will be taken out of the
2113 block. Return NULL if either edge may be taken. */
2116 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2121 dest
= label_to_block (val
);
2124 e
= find_edge (bb
, dest
);
2125 gcc_assert (e
!= NULL
);
2131 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2132 statement, determine which of the two edges will be taken out of the
2133 block. Return NULL if either edge may be taken. */
2136 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2138 edge true_edge
, false_edge
;
2140 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2142 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2143 return (integer_zerop (val
) ? false_edge
: true_edge
);
2146 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2147 statement, determine which edge will be taken out of the block. Return
2148 NULL if any edge may be taken. */
2151 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2153 tree switch_expr
, taken_case
;
2154 basic_block dest_bb
;
2157 switch_expr
= last_stmt (bb
);
2158 taken_case
= find_case_label_for_value (switch_expr
, val
);
2159 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2161 e
= find_edge (bb
, dest_bb
);
2167 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2168 We can make optimal use here of the fact that the case labels are
2169 sorted: We can do a binary search for a case matching VAL. */
2172 find_case_label_for_value (tree switch_expr
, tree val
)
2174 tree vec
= SWITCH_LABELS (switch_expr
);
2175 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2176 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2178 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2180 size_t i
= (high
+ low
) / 2;
2181 tree t
= TREE_VEC_ELT (vec
, i
);
2184 /* Cache the result of comparing CASE_LOW and val. */
2185 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2192 if (CASE_HIGH (t
) == NULL
)
2194 /* A singe-valued case label. */
2200 /* A case range. We can only handle integer ranges. */
2201 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2206 return default_case
;
2212 /*---------------------------------------------------------------------------
2214 ---------------------------------------------------------------------------*/
2216 /* Dump tree-specific information of block BB to file OUTF. */
2219 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2221 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
|TDF_MEMSYMS
);
2225 /* Dump a basic block on stderr. */
2228 debug_tree_bb (basic_block bb
)
2230 dump_bb (bb
, stderr
, 0);
2234 /* Dump basic block with index N on stderr. */
2237 debug_tree_bb_n (int n
)
2239 debug_tree_bb (BASIC_BLOCK (n
));
2240 return BASIC_BLOCK (n
);
2244 /* Dump the CFG on stderr.
2246 FLAGS are the same used by the tree dumping functions
2247 (see TDF_* in tree-pass.h). */
2250 debug_tree_cfg (int flags
)
2252 dump_tree_cfg (stderr
, flags
);
2256 /* Dump the program showing basic block boundaries on the given FILE.
2258 FLAGS are the same used by the tree dumping functions (see TDF_* in
2262 dump_tree_cfg (FILE *file
, int flags
)
2264 if (flags
& TDF_DETAILS
)
2266 const char *funcname
2267 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2270 fprintf (file
, ";; Function %s\n\n", funcname
);
2271 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2272 n_basic_blocks
, n_edges
, last_basic_block
);
2274 brief_dump_cfg (file
);
2275 fprintf (file
, "\n");
2278 if (flags
& TDF_STATS
)
2279 dump_cfg_stats (file
);
2281 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2285 /* Dump CFG statistics on FILE. */
2288 dump_cfg_stats (FILE *file
)
2290 static long max_num_merged_labels
= 0;
2291 unsigned long size
, total
= 0;
2294 const char * const fmt_str
= "%-30s%-13s%12s\n";
2295 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2296 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2297 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2298 const char *funcname
2299 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2302 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2304 fprintf (file
, "---------------------------------------------------------\n");
2305 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2306 fprintf (file
, fmt_str
, "", " instances ", "used ");
2307 fprintf (file
, "---------------------------------------------------------\n");
2309 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2311 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2312 SCALE (size
), LABEL (size
));
2316 num_edges
+= EDGE_COUNT (bb
->succs
);
2317 size
= num_edges
* sizeof (struct edge_def
);
2319 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2321 fprintf (file
, "---------------------------------------------------------\n");
2322 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2324 fprintf (file
, "---------------------------------------------------------\n");
2325 fprintf (file
, "\n");
2327 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2328 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2330 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2331 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2333 fprintf (file
, "\n");
2337 /* Dump CFG statistics on stderr. Keep extern so that it's always
2338 linked in the final executable. */
2341 debug_cfg_stats (void)
2343 dump_cfg_stats (stderr
);
2347 /* Dump the flowgraph to a .vcg FILE. */
2350 tree_cfg2vcg (FILE *file
)
2355 const char *funcname
2356 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2358 /* Write the file header. */
2359 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2360 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2361 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2363 /* Write blocks and edges. */
2364 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2366 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2369 if (e
->flags
& EDGE_FAKE
)
2370 fprintf (file
, " linestyle: dotted priority: 10");
2372 fprintf (file
, " linestyle: solid priority: 100");
2374 fprintf (file
, " }\n");
2380 enum tree_code head_code
, end_code
;
2381 const char *head_name
, *end_name
;
2384 tree first
= first_stmt (bb
);
2385 tree last
= last_stmt (bb
);
2389 head_code
= TREE_CODE (first
);
2390 head_name
= tree_code_name
[head_code
];
2391 head_line
= get_lineno (first
);
2394 head_name
= "no-statement";
2398 end_code
= TREE_CODE (last
);
2399 end_name
= tree_code_name
[end_code
];
2400 end_line
= get_lineno (last
);
2403 end_name
= "no-statement";
2405 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2406 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2409 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2411 if (e
->dest
== EXIT_BLOCK_PTR
)
2412 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2414 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2416 if (e
->flags
& EDGE_FAKE
)
2417 fprintf (file
, " priority: 10 linestyle: dotted");
2419 fprintf (file
, " priority: 100 linestyle: solid");
2421 fprintf (file
, " }\n");
2424 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2428 fputs ("}\n\n", file
);
2433 /*---------------------------------------------------------------------------
2434 Miscellaneous helpers
2435 ---------------------------------------------------------------------------*/
2437 /* Return true if T represents a stmt that always transfers control. */
2440 is_ctrl_stmt (tree t
)
2442 return (TREE_CODE (t
) == COND_EXPR
2443 || TREE_CODE (t
) == SWITCH_EXPR
2444 || TREE_CODE (t
) == GOTO_EXPR
2445 || TREE_CODE (t
) == RETURN_EXPR
2446 || TREE_CODE (t
) == RESX_EXPR
);
2450 /* Return true if T is a statement that may alter the flow of control
2451 (e.g., a call to a non-returning function). */
2454 is_ctrl_altering_stmt (tree t
)
2459 call
= get_call_expr_in (t
);
2462 /* A non-pure/const CALL_EXPR alters flow control if the current
2463 function has nonlocal labels. */
2464 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2467 /* A CALL_EXPR also alters control flow if it does not return. */
2468 if (call_expr_flags (call
) & ECF_NORETURN
)
2472 /* OpenMP directives alter control flow. */
2473 if (OMP_DIRECTIVE_P (t
))
2476 /* If a statement can throw, it alters control flow. */
2477 return tree_can_throw_internal (t
);
2481 /* Return true if T is a computed goto. */
2484 computed_goto_p (tree t
)
2486 return (TREE_CODE (t
) == GOTO_EXPR
2487 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2491 /* Return true if T is a simple local goto. */
2494 simple_goto_p (tree t
)
2496 return (TREE_CODE (t
) == GOTO_EXPR
2497 && TREE_CODE (GOTO_DESTINATION (t
)) == LABEL_DECL
);
2501 /* Return true if T can make an abnormal transfer of control flow.
2502 Transfers of control flow associated with EH are excluded. */
2505 tree_can_make_abnormal_goto (tree t
)
2507 if (computed_goto_p (t
))
2509 if (TREE_CODE (t
) == GIMPLE_MODIFY_STMT
)
2510 t
= GIMPLE_STMT_OPERAND (t
, 1);
2511 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2512 t
= TREE_OPERAND (t
, 0);
2513 if (TREE_CODE (t
) == CALL_EXPR
)
2514 return TREE_SIDE_EFFECTS (t
) && current_function_has_nonlocal_label
;
2519 /* Return true if T should start a new basic block. PREV_T is the
2520 statement preceding T. It is used when T is a label or a case label.
2521 Labels should only start a new basic block if their previous statement
2522 wasn't a label. Otherwise, sequence of labels would generate
2523 unnecessary basic blocks that only contain a single label. */
2526 stmt_starts_bb_p (tree t
, tree prev_t
)
2531 /* LABEL_EXPRs start a new basic block only if the preceding
2532 statement wasn't a label of the same type. This prevents the
2533 creation of consecutive blocks that have nothing but a single
2535 if (TREE_CODE (t
) == LABEL_EXPR
)
2537 /* Nonlocal and computed GOTO targets always start a new block. */
2538 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2539 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2542 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2544 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2547 cfg_stats
.num_merged_labels
++;
2558 /* Return true if T should end a basic block. */
2561 stmt_ends_bb_p (tree t
)
2563 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2567 /* Add gotos that used to be represented implicitly in the CFG. */
2570 disband_implicit_edges (void)
2573 block_stmt_iterator last
;
2580 last
= bsi_last (bb
);
2581 stmt
= last_stmt (bb
);
2583 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2585 /* Remove superfluous gotos from COND_EXPR branches. Moved
2586 from cfg_remove_useless_stmts here since it violates the
2587 invariants for tree--cfg correspondence and thus fits better
2588 here where we do it anyway. */
2589 e
= find_edge (bb
, bb
->next_bb
);
2592 if (e
->flags
& EDGE_TRUE_VALUE
)
2593 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2594 else if (e
->flags
& EDGE_FALSE_VALUE
)
2595 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2598 e
->flags
|= EDGE_FALLTHRU
;
2604 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2606 /* Remove the RETURN_EXPR if we may fall though to the exit
2608 gcc_assert (single_succ_p (bb
));
2609 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2611 if (bb
->next_bb
== EXIT_BLOCK_PTR
2612 && !TREE_OPERAND (stmt
, 0))
2614 bsi_remove (&last
, true);
2615 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2620 /* There can be no fallthru edge if the last statement is a control
2622 if (stmt
&& is_ctrl_stmt (stmt
))
2625 /* Find a fallthru edge and emit the goto if necessary. */
2626 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2627 if (e
->flags
& EDGE_FALLTHRU
)
2630 if (!e
|| e
->dest
== bb
->next_bb
)
2633 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2634 label
= tree_block_label (e
->dest
);
2636 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2637 #ifdef USE_MAPPED_LOCATION
2638 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2640 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2642 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2643 e
->flags
&= ~EDGE_FALLTHRU
;
2647 /* Remove block annotations and other datastructures. */
2650 delete_tree_cfg_annotations (void)
2652 label_to_block_map
= NULL
;
2656 /* Return the first statement in basic block BB. */
2659 first_stmt (basic_block bb
)
2661 block_stmt_iterator i
= bsi_start (bb
);
2662 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2666 /* Return the last statement in basic block BB. */
2669 last_stmt (basic_block bb
)
2671 block_stmt_iterator b
= bsi_last (bb
);
2672 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2676 /* Return the last statement of an otherwise empty block. Return NULL
2677 if the block is totally empty, or if it contains more than one
2681 last_and_only_stmt (basic_block bb
)
2683 block_stmt_iterator i
= bsi_last (bb
);
2689 last
= bsi_stmt (i
);
2694 /* Empty statements should no longer appear in the instruction stream.
2695 Everything that might have appeared before should be deleted by
2696 remove_useless_stmts, and the optimizers should just bsi_remove
2697 instead of smashing with build_empty_stmt.
2699 Thus the only thing that should appear here in a block containing
2700 one executable statement is a label. */
2701 prev
= bsi_stmt (i
);
2702 if (TREE_CODE (prev
) == LABEL_EXPR
)
2709 /* Mark BB as the basic block holding statement T. */
2712 set_bb_for_stmt (tree t
, basic_block bb
)
2714 if (TREE_CODE (t
) == PHI_NODE
)
2716 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2718 tree_stmt_iterator i
;
2719 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2720 set_bb_for_stmt (tsi_stmt (i
), bb
);
2724 stmt_ann_t ann
= get_stmt_ann (t
);
2727 /* If the statement is a label, add the label to block-to-labels map
2728 so that we can speed up edge creation for GOTO_EXPRs. */
2729 if (TREE_CODE (t
) == LABEL_EXPR
)
2733 t
= LABEL_EXPR_LABEL (t
);
2734 uid
= LABEL_DECL_UID (t
);
2737 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2738 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2739 if (old_len
<= (unsigned) uid
)
2741 unsigned new_len
= 3 * uid
/ 2;
2743 VEC_safe_grow_cleared (basic_block
, gc
, label_to_block_map
,
2748 /* We're moving an existing label. Make sure that we've
2749 removed it from the old block. */
2751 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2752 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2757 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2758 from one basic block to another.
2759 For BB splitting we can run into quadratic case, so performance is quite
2760 important and knowing that the tables are big enough, change_bb_for_stmt
2761 can inline as leaf function. */
2763 change_bb_for_stmt (tree t
, basic_block bb
)
2765 get_stmt_ann (t
)->bb
= bb
;
2766 if (TREE_CODE (t
) == LABEL_EXPR
)
2767 VEC_replace (basic_block
, label_to_block_map
,
2768 LABEL_DECL_UID (LABEL_EXPR_LABEL (t
)), bb
);
2771 /* Finds iterator for STMT. */
2773 extern block_stmt_iterator
2774 bsi_for_stmt (tree stmt
)
2776 block_stmt_iterator bsi
;
2778 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2779 if (bsi_stmt (bsi
) == stmt
)
2785 /* Mark statement T as modified, and update it. */
2787 update_modified_stmts (tree t
)
2789 if (!ssa_operands_active ())
2791 if (TREE_CODE (t
) == STATEMENT_LIST
)
2793 tree_stmt_iterator i
;
2795 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2797 stmt
= tsi_stmt (i
);
2798 update_stmt_if_modified (stmt
);
2802 update_stmt_if_modified (t
);
2805 /* Insert statement (or statement list) T before the statement
2806 pointed-to by iterator I. M specifies how to update iterator I
2807 after insertion (see enum bsi_iterator_update). */
2810 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2812 set_bb_for_stmt (t
, i
->bb
);
2813 update_modified_stmts (t
);
2814 tsi_link_before (&i
->tsi
, t
, m
);
2818 /* Insert statement (or statement list) T after the statement
2819 pointed-to by iterator I. M specifies how to update iterator I
2820 after insertion (see enum bsi_iterator_update). */
2823 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2825 set_bb_for_stmt (t
, i
->bb
);
2826 update_modified_stmts (t
);
2827 tsi_link_after (&i
->tsi
, t
, m
);
2831 /* Remove the statement pointed to by iterator I. The iterator is updated
2832 to the next statement.
2834 When REMOVE_EH_INFO is true we remove the statement pointed to by
2835 iterator I from the EH tables. Otherwise we do not modify the EH
2838 Generally, REMOVE_EH_INFO should be true when the statement is going to
2839 be removed from the IL and not reinserted elsewhere. */
2842 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2844 tree t
= bsi_stmt (*i
);
2845 set_bb_for_stmt (t
, NULL
);
2846 delink_stmt_imm_use (t
);
2847 tsi_delink (&i
->tsi
);
2848 mark_stmt_modified (t
);
2851 remove_stmt_from_eh_region (t
);
2852 gimple_remove_stmt_histograms (cfun
, t
);
2857 /* Move the statement at FROM so it comes right after the statement at TO. */
2860 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2862 tree stmt
= bsi_stmt (*from
);
2863 bsi_remove (from
, false);
2864 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2868 /* Move the statement at FROM so it comes right before the statement at TO. */
2871 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2873 tree stmt
= bsi_stmt (*from
);
2874 bsi_remove (from
, false);
2875 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2879 /* Move the statement at FROM to the end of basic block BB. */
2882 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2884 block_stmt_iterator last
= bsi_last (bb
);
2886 /* Have to check bsi_end_p because it could be an empty block. */
2887 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2888 bsi_move_before (from
, &last
);
2890 bsi_move_after (from
, &last
);
2894 /* Replace the contents of the statement pointed to by iterator BSI
2895 with STMT. If UPDATE_EH_INFO is true, the exception handling
2896 information of the original statement is moved to the new statement. */
2899 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2902 tree orig_stmt
= bsi_stmt (*bsi
);
2904 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2905 set_bb_for_stmt (stmt
, bsi
->bb
);
2907 /* Preserve EH region information from the original statement, if
2908 requested by the caller. */
2911 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2914 remove_stmt_from_eh_region (orig_stmt
);
2915 add_stmt_to_eh_region (stmt
, eh_region
);
2916 gimple_duplicate_stmt_histograms (cfun
, stmt
, cfun
, orig_stmt
);
2917 gimple_remove_stmt_histograms (cfun
, orig_stmt
);
2921 delink_stmt_imm_use (orig_stmt
);
2922 *bsi_stmt_ptr (*bsi
) = stmt
;
2923 mark_stmt_modified (stmt
);
2924 update_modified_stmts (stmt
);
2928 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2929 is made to place the statement in an existing basic block, but
2930 sometimes that isn't possible. When it isn't possible, the edge is
2931 split and the statement is added to the new block.
2933 In all cases, the returned *BSI points to the correct location. The
2934 return value is true if insertion should be done after the location,
2935 or false if it should be done before the location. If new basic block
2936 has to be created, it is stored in *NEW_BB. */
2939 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2940 basic_block
*new_bb
)
2942 basic_block dest
, src
;
2948 /* If the destination has one predecessor which has no PHI nodes,
2949 insert there. Except for the exit block.
2951 The requirement for no PHI nodes could be relaxed. Basically we
2952 would have to examine the PHIs to prove that none of them used
2953 the value set by the statement we want to insert on E. That
2954 hardly seems worth the effort. */
2955 if (single_pred_p (dest
)
2956 && ! phi_nodes (dest
)
2957 && dest
!= EXIT_BLOCK_PTR
)
2959 *bsi
= bsi_start (dest
);
2960 if (bsi_end_p (*bsi
))
2963 /* Make sure we insert after any leading labels. */
2964 tmp
= bsi_stmt (*bsi
);
2965 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2968 if (bsi_end_p (*bsi
))
2970 tmp
= bsi_stmt (*bsi
);
2973 if (bsi_end_p (*bsi
))
2975 *bsi
= bsi_last (dest
);
2982 /* If the source has one successor, the edge is not abnormal and
2983 the last statement does not end a basic block, insert there.
2984 Except for the entry block. */
2986 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2987 && single_succ_p (src
)
2988 && src
!= ENTRY_BLOCK_PTR
)
2990 *bsi
= bsi_last (src
);
2991 if (bsi_end_p (*bsi
))
2994 tmp
= bsi_stmt (*bsi
);
2995 if (!stmt_ends_bb_p (tmp
))
2998 /* Insert code just before returning the value. We may need to decompose
2999 the return in the case it contains non-trivial operand. */
3000 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3002 tree op
= TREE_OPERAND (tmp
, 0);
3003 if (op
&& !is_gimple_val (op
))
3005 gcc_assert (TREE_CODE (op
) == GIMPLE_MODIFY_STMT
);
3006 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3007 TREE_OPERAND (tmp
, 0) = GIMPLE_STMT_OPERAND (op
, 0);
3014 /* Otherwise, create a new basic block, and split this edge. */
3015 dest
= split_edge (e
);
3018 e
= single_pred_edge (dest
);
3023 /* This routine will commit all pending edge insertions, creating any new
3024 basic blocks which are necessary. */
3027 bsi_commit_edge_inserts (void)
3033 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3036 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3037 bsi_commit_one_edge_insert (e
, NULL
);
3041 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3042 to this block, otherwise set it to NULL. */
3045 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3049 if (PENDING_STMT (e
))
3051 block_stmt_iterator bsi
;
3052 tree stmt
= PENDING_STMT (e
);
3054 PENDING_STMT (e
) = NULL_TREE
;
3056 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3057 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3059 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3064 /* Add STMT to the pending list of edge E. No actual insertion is
3065 made until a call to bsi_commit_edge_inserts () is made. */
3068 bsi_insert_on_edge (edge e
, tree stmt
)
3070 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3073 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3074 block has to be created, it is returned. */
3077 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3079 block_stmt_iterator bsi
;
3080 basic_block new_bb
= NULL
;
3082 gcc_assert (!PENDING_STMT (e
));
3084 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3085 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3087 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3092 /*---------------------------------------------------------------------------
3093 Tree specific functions for CFG manipulation
3094 ---------------------------------------------------------------------------*/
3096 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3099 reinstall_phi_args (edge new_edge
, edge old_edge
)
3103 if (!PENDING_STMT (old_edge
))
3106 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3108 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3110 tree result
= TREE_PURPOSE (var
);
3111 tree arg
= TREE_VALUE (var
);
3113 gcc_assert (result
== PHI_RESULT (phi
));
3115 add_phi_arg (phi
, arg
, new_edge
);
3118 PENDING_STMT (old_edge
) = NULL
;
3121 /* Returns the basic block after which the new basic block created
3122 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3123 near its "logical" location. This is of most help to humans looking
3124 at debugging dumps. */
3127 split_edge_bb_loc (edge edge_in
)
3129 basic_block dest
= edge_in
->dest
;
3131 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3132 return edge_in
->src
;
3134 return dest
->prev_bb
;
3137 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3138 Abort on abnormal edges. */
3141 tree_split_edge (edge edge_in
)
3143 basic_block new_bb
, after_bb
, dest
;
3146 /* Abnormal edges cannot be split. */
3147 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3149 dest
= edge_in
->dest
;
3151 after_bb
= split_edge_bb_loc (edge_in
);
3153 new_bb
= create_empty_bb (after_bb
);
3154 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3155 new_bb
->count
= edge_in
->count
;
3156 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3157 new_edge
->probability
= REG_BR_PROB_BASE
;
3158 new_edge
->count
= edge_in
->count
;
3160 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3162 reinstall_phi_args (new_edge
, e
);
3168 /* Return true when BB has label LABEL in it. */
3171 has_label_p (basic_block bb
, tree label
)
3173 block_stmt_iterator bsi
;
3175 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3177 tree stmt
= bsi_stmt (bsi
);
3179 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3181 if (LABEL_EXPR_LABEL (stmt
) == label
)
3188 /* Callback for walk_tree, check that all elements with address taken are
3189 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3190 inside a PHI node. */
3193 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3196 bool in_phi
= (data
!= NULL
);
3201 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3202 #define CHECK_OP(N, MSG) \
3203 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3204 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3206 switch (TREE_CODE (t
))
3209 if (SSA_NAME_IN_FREE_LIST (t
))
3211 error ("SSA name in freelist but still referenced");
3217 x
= fold (ASSERT_EXPR_COND (t
));
3218 if (x
== boolean_false_node
)
3220 error ("ASSERT_EXPR with an always-false condition");
3228 case GIMPLE_MODIFY_STMT
:
3229 x
= GIMPLE_STMT_OPERAND (t
, 0);
3230 if (TREE_CODE (x
) == BIT_FIELD_REF
3231 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3233 error ("GIMPLE register modified with BIT_FIELD_REF");
3242 bool old_side_effects
;
3245 bool new_side_effects
;
3247 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3248 dead PHIs that take the address of something. But if the PHI
3249 result is dead, the fact that it takes the address of anything
3250 is irrelevant. Because we can not tell from here if a PHI result
3251 is dead, we just skip this check for PHIs altogether. This means
3252 we may be missing "valid" checks, but what can you do?
3253 This was PR19217. */
3257 old_invariant
= TREE_INVARIANT (t
);
3258 old_constant
= TREE_CONSTANT (t
);
3259 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3261 recompute_tree_invariant_for_addr_expr (t
);
3262 new_invariant
= TREE_INVARIANT (t
);
3263 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3264 new_constant
= TREE_CONSTANT (t
);
3266 if (old_invariant
!= new_invariant
)
3268 error ("invariant not recomputed when ADDR_EXPR changed");
3272 if (old_constant
!= new_constant
)
3274 error ("constant not recomputed when ADDR_EXPR changed");
3277 if (old_side_effects
!= new_side_effects
)
3279 error ("side effects not recomputed when ADDR_EXPR changed");
3283 /* Skip any references (they will be checked when we recurse down the
3284 tree) and ensure that any variable used as a prefix is marked
3286 for (x
= TREE_OPERAND (t
, 0);
3287 handled_component_p (x
);
3288 x
= TREE_OPERAND (x
, 0))
3291 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3293 if (!TREE_ADDRESSABLE (x
))
3295 error ("address taken, but ADDRESSABLE bit not set");
3302 x
= COND_EXPR_COND (t
);
3303 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3305 error ("non-boolean used in condition");
3308 if (!is_gimple_condexpr (x
))
3310 error ("invalid conditional operand");
3317 case FIX_TRUNC_EXPR
:
3322 case NON_LVALUE_EXPR
:
3323 case TRUTH_NOT_EXPR
:
3324 CHECK_OP (0, "invalid operand to unary operator");
3331 case ARRAY_RANGE_REF
:
3333 case VIEW_CONVERT_EXPR
:
3334 /* We have a nest of references. Verify that each of the operands
3335 that determine where to reference is either a constant or a variable,
3336 verify that the base is valid, and then show we've already checked
3338 while (handled_component_p (t
))
3340 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3341 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3342 else if (TREE_CODE (t
) == ARRAY_REF
3343 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3345 CHECK_OP (1, "invalid array index");
3346 if (TREE_OPERAND (t
, 2))
3347 CHECK_OP (2, "invalid array lower bound");
3348 if (TREE_OPERAND (t
, 3))
3349 CHECK_OP (3, "invalid array stride");
3351 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3353 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3354 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3357 t
= TREE_OPERAND (t
, 0);
3360 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3362 error ("invalid reference prefix");
3374 case UNORDERED_EXPR
:
3385 case TRUNC_DIV_EXPR
:
3387 case FLOOR_DIV_EXPR
:
3388 case ROUND_DIV_EXPR
:
3389 case TRUNC_MOD_EXPR
:
3391 case FLOOR_MOD_EXPR
:
3392 case ROUND_MOD_EXPR
:
3394 case EXACT_DIV_EXPR
:
3404 CHECK_OP (0, "invalid operand to binary operator");
3405 CHECK_OP (1, "invalid operand to binary operator");
3409 if (TREE_CONSTANT (t
) && TREE_CODE (TREE_TYPE (t
)) == VECTOR_TYPE
)
3422 /* Verify STMT, return true if STMT is not in GIMPLE form.
3423 TODO: Implement type checking. */
3426 verify_stmt (tree stmt
, bool last_in_block
)
3430 if (OMP_DIRECTIVE_P (stmt
))
3432 /* OpenMP directives are validated by the FE and never operated
3433 on by the optimizers. Furthermore, OMP_FOR may contain
3434 non-gimple expressions when the main index variable has had
3435 its address taken. This does not affect the loop itself
3436 because the header of an OMP_FOR is merely used to determine
3437 how to setup the parallel iteration. */
3441 if (!is_gimple_stmt (stmt
))
3443 error ("is not a valid GIMPLE statement");
3447 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3450 debug_generic_stmt (addr
);
3454 /* If the statement is marked as part of an EH region, then it is
3455 expected that the statement could throw. Verify that when we
3456 have optimizations that simplify statements such that we prove
3457 that they cannot throw, that we update other data structures
3459 if (lookup_stmt_eh_region (stmt
) >= 0)
3461 if (!tree_could_throw_p (stmt
))
3463 error ("statement marked for throw, but doesn%'t");
3466 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3468 error ("statement marked for throw in middle of block");
3476 debug_generic_stmt (stmt
);
3481 /* Return true when the T can be shared. */
3484 tree_node_can_be_shared (tree t
)
3486 if (IS_TYPE_OR_DECL_P (t
)
3487 || is_gimple_min_invariant (t
)
3488 || TREE_CODE (t
) == SSA_NAME
3489 || t
== error_mark_node
3490 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3493 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3496 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3497 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3498 || TREE_CODE (t
) == COMPONENT_REF
3499 || TREE_CODE (t
) == REALPART_EXPR
3500 || TREE_CODE (t
) == IMAGPART_EXPR
)
3501 t
= TREE_OPERAND (t
, 0);
3510 /* Called via walk_trees. Verify tree sharing. */
3513 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3515 htab_t htab
= (htab_t
) data
;
3518 if (tree_node_can_be_shared (*tp
))
3520 *walk_subtrees
= false;
3524 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3526 return (tree
) *slot
;
3533 /* Helper function for verify_gimple_tuples. */
3536 verify_gimple_tuples_1 (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
3537 void *data ATTRIBUTE_UNUSED
)
3539 switch (TREE_CODE (*tp
))
3542 error ("unexpected non-tuple");
3552 /* Verify that there are no trees that should have been converted to
3553 gimple tuples. Return true if T contains a node that should have
3554 been converted to a gimple tuple, but hasn't. */
3557 verify_gimple_tuples (tree t
)
3559 return walk_tree (&t
, verify_gimple_tuples_1
, NULL
, NULL
) != NULL
;
3562 /* Verify the GIMPLE statement chain. */
3568 block_stmt_iterator bsi
;
3573 timevar_push (TV_TREE_STMT_VERIFY
);
3574 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3581 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3583 int phi_num_args
= PHI_NUM_ARGS (phi
);
3585 if (bb_for_stmt (phi
) != bb
)
3587 error ("bb_for_stmt (phi) is set to a wrong basic block");
3591 for (i
= 0; i
< phi_num_args
; i
++)
3593 tree t
= PHI_ARG_DEF (phi
, i
);
3596 /* Addressable variables do have SSA_NAMEs but they
3597 are not considered gimple values. */
3598 if (TREE_CODE (t
) != SSA_NAME
3599 && TREE_CODE (t
) != FUNCTION_DECL
3600 && !is_gimple_val (t
))
3602 error ("PHI def is not a GIMPLE value");
3603 debug_generic_stmt (phi
);
3604 debug_generic_stmt (t
);
3608 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3611 debug_generic_stmt (addr
);
3615 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3618 error ("incorrect sharing of tree nodes");
3619 debug_generic_stmt (phi
);
3620 debug_generic_stmt (addr
);
3626 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3628 tree stmt
= bsi_stmt (bsi
);
3630 err
|= verify_gimple_tuples (stmt
);
3632 if (bb_for_stmt (stmt
) != bb
)
3634 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3639 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3640 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3643 error ("incorrect sharing of tree nodes");
3644 debug_generic_stmt (stmt
);
3645 debug_generic_stmt (addr
);
3652 internal_error ("verify_stmts failed");
3655 verify_histograms ();
3656 timevar_pop (TV_TREE_STMT_VERIFY
);
3660 /* Verifies that the flow information is OK. */
3663 tree_verify_flow_info (void)
3667 block_stmt_iterator bsi
;
3672 if (ENTRY_BLOCK_PTR
->stmt_list
)
3674 error ("ENTRY_BLOCK has a statement list associated with it");
3678 if (EXIT_BLOCK_PTR
->stmt_list
)
3680 error ("EXIT_BLOCK has a statement list associated with it");
3684 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3685 if (e
->flags
& EDGE_FALLTHRU
)
3687 error ("fallthru to exit from bb %d", e
->src
->index
);
3693 bool found_ctrl_stmt
= false;
3697 /* Skip labels on the start of basic block. */
3698 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3700 tree prev_stmt
= stmt
;
3702 stmt
= bsi_stmt (bsi
);
3704 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3707 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3709 error ("nonlocal label ");
3710 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3711 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3716 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3719 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3720 fprintf (stderr
, " to block does not match in bb %d",
3725 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3726 != current_function_decl
)
3729 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3730 fprintf (stderr
, " has incorrect context in bb %d",
3736 /* Verify that body of basic block BB is free of control flow. */
3737 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3739 tree stmt
= bsi_stmt (bsi
);
3741 if (found_ctrl_stmt
)
3743 error ("control flow in the middle of basic block %d",
3748 if (stmt_ends_bb_p (stmt
))
3749 found_ctrl_stmt
= true;
3751 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3754 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3755 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3760 bsi
= bsi_last (bb
);
3761 if (bsi_end_p (bsi
))
3764 stmt
= bsi_stmt (bsi
);
3766 err
|= verify_eh_edges (stmt
);
3768 if (is_ctrl_stmt (stmt
))
3770 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3771 if (e
->flags
& EDGE_FALLTHRU
)
3773 error ("fallthru edge after a control statement in bb %d",
3779 if (TREE_CODE (stmt
) != COND_EXPR
)
3781 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3782 after anything else but if statement. */
3783 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3784 if (e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
))
3786 error ("true/false edge after a non-COND_EXPR in bb %d",
3792 switch (TREE_CODE (stmt
))
3798 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3799 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3801 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3805 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3807 if (!true_edge
|| !false_edge
3808 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3809 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3810 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3811 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3812 || EDGE_COUNT (bb
->succs
) >= 3)
3814 error ("wrong outgoing edge flags at end of bb %d",
3819 if (!has_label_p (true_edge
->dest
,
3820 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3822 error ("%<then%> label does not match edge at end of bb %d",
3827 if (!has_label_p (false_edge
->dest
,
3828 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3830 error ("%<else%> label does not match edge at end of bb %d",
3838 if (simple_goto_p (stmt
))
3840 error ("explicit goto at end of bb %d", bb
->index
);
3845 /* FIXME. We should double check that the labels in the
3846 destination blocks have their address taken. */
3847 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3848 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3849 | EDGE_FALSE_VALUE
))
3850 || !(e
->flags
& EDGE_ABNORMAL
))
3852 error ("wrong outgoing edge flags at end of bb %d",
3860 if (!single_succ_p (bb
)
3861 || (single_succ_edge (bb
)->flags
3862 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3863 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3865 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3868 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3870 error ("return edge does not point to exit in bb %d",
3883 vec
= SWITCH_LABELS (stmt
);
3884 n
= TREE_VEC_LENGTH (vec
);
3886 /* Mark all the destination basic blocks. */
3887 for (i
= 0; i
< n
; ++i
)
3889 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3890 basic_block label_bb
= label_to_block (lab
);
3892 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3893 label_bb
->aux
= (void *)1;
3896 /* Verify that the case labels are sorted. */
3897 prev
= TREE_VEC_ELT (vec
, 0);
3898 for (i
= 1; i
< n
- 1; ++i
)
3900 tree c
= TREE_VEC_ELT (vec
, i
);
3903 error ("found default case not at end of case vector");
3907 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3909 error ("case labels not sorted: ");
3910 print_generic_expr (stderr
, prev
, 0);
3911 fprintf (stderr
," is greater than ");
3912 print_generic_expr (stderr
, c
, 0);
3913 fprintf (stderr
," but comes before it.\n");
3918 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3920 error ("no default case found at end of case vector");
3924 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3928 error ("extra outgoing edge %d->%d",
3929 bb
->index
, e
->dest
->index
);
3932 e
->dest
->aux
= (void *)2;
3933 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3934 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3936 error ("wrong outgoing edge flags at end of bb %d",
3942 /* Check that we have all of them. */
3943 for (i
= 0; i
< n
; ++i
)
3945 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3946 basic_block label_bb
= label_to_block (lab
);
3948 if (label_bb
->aux
!= (void *)2)
3950 error ("missing edge %i->%i",
3951 bb
->index
, label_bb
->index
);
3956 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3957 e
->dest
->aux
= (void *)0;
3964 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3965 verify_dominators (CDI_DOMINATORS
);
3971 /* Updates phi nodes after creating a forwarder block joined
3972 by edge FALLTHRU. */
3975 tree_make_forwarder_block (edge fallthru
)
3979 basic_block dummy
, bb
;
3980 tree phi
, new_phi
, var
;
3982 dummy
= fallthru
->src
;
3983 bb
= fallthru
->dest
;
3985 if (single_pred_p (bb
))
3988 /* If we redirected a branch we must create new PHI nodes at the
3990 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3992 var
= PHI_RESULT (phi
);
3993 new_phi
= create_phi_node (var
, bb
);
3994 SSA_NAME_DEF_STMT (var
) = new_phi
;
3995 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3996 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3999 /* Ensure that the PHI node chain is in the same order. */
4000 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
4002 /* Add the arguments we have stored on edges. */
4003 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4008 flush_pending_stmts (e
);
4013 /* Return a non-special label in the head of basic block BLOCK.
4014 Create one if it doesn't exist. */
4017 tree_block_label (basic_block bb
)
4019 block_stmt_iterator i
, s
= bsi_start (bb
);
4023 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4025 stmt
= bsi_stmt (i
);
4026 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4028 label
= LABEL_EXPR_LABEL (stmt
);
4029 if (!DECL_NONLOCAL (label
))
4032 bsi_move_before (&i
, &s
);
4037 label
= create_artificial_label ();
4038 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4039 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4044 /* Attempt to perform edge redirection by replacing a possibly complex
4045 jump instruction by a goto or by removing the jump completely.
4046 This can apply only if all edges now point to the same block. The
4047 parameters and return values are equivalent to
4048 redirect_edge_and_branch. */
4051 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4053 basic_block src
= e
->src
;
4054 block_stmt_iterator b
;
4057 /* We can replace or remove a complex jump only when we have exactly
4059 if (EDGE_COUNT (src
->succs
) != 2
4060 /* Verify that all targets will be TARGET. Specifically, the
4061 edge that is not E must also go to TARGET. */
4062 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4068 stmt
= bsi_stmt (b
);
4070 if (TREE_CODE (stmt
) == COND_EXPR
4071 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4073 bsi_remove (&b
, true);
4074 e
= ssa_redirect_edge (e
, target
);
4075 e
->flags
= EDGE_FALLTHRU
;
4083 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4084 edge representing the redirected branch. */
4087 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4089 basic_block bb
= e
->src
;
4090 block_stmt_iterator bsi
;
4094 if (e
->flags
& EDGE_ABNORMAL
)
4097 if (e
->src
!= ENTRY_BLOCK_PTR
4098 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4101 if (e
->dest
== dest
)
4104 label
= tree_block_label (dest
);
4106 bsi
= bsi_last (bb
);
4107 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4109 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4112 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4113 ? COND_EXPR_THEN (stmt
)
4114 : COND_EXPR_ELSE (stmt
));
4115 GOTO_DESTINATION (stmt
) = label
;
4119 /* No non-abnormal edges should lead from a non-simple goto, and
4120 simple ones should be represented implicitly. */
4125 tree cases
= get_cases_for_edge (e
, stmt
);
4127 /* If we have a list of cases associated with E, then use it
4128 as it's a lot faster than walking the entire case vector. */
4131 edge e2
= find_edge (e
->src
, dest
);
4138 CASE_LABEL (cases
) = label
;
4139 cases
= TREE_CHAIN (cases
);
4142 /* If there was already an edge in the CFG, then we need
4143 to move all the cases associated with E to E2. */
4146 tree cases2
= get_cases_for_edge (e2
, stmt
);
4148 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4149 TREE_CHAIN (cases2
) = first
;
4154 tree vec
= SWITCH_LABELS (stmt
);
4155 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4157 for (i
= 0; i
< n
; i
++)
4159 tree elt
= TREE_VEC_ELT (vec
, i
);
4161 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4162 CASE_LABEL (elt
) = label
;
4170 bsi_remove (&bsi
, true);
4171 e
->flags
|= EDGE_FALLTHRU
;
4175 /* Otherwise it must be a fallthru edge, and we don't need to
4176 do anything besides redirecting it. */
4177 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4181 /* Update/insert PHI nodes as necessary. */
4183 /* Now update the edges in the CFG. */
4184 e
= ssa_redirect_edge (e
, dest
);
4190 /* Simple wrapper, as we can always redirect fallthru edges. */
4193 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4195 e
= tree_redirect_edge_and_branch (e
, dest
);
4202 /* Splits basic block BB after statement STMT (but at least after the
4203 labels). If STMT is NULL, BB is split just after the labels. */
4206 tree_split_block (basic_block bb
, void *stmt
)
4208 block_stmt_iterator bsi
;
4209 tree_stmt_iterator tsi_tgt
;
4215 new_bb
= create_empty_bb (bb
);
4217 /* Redirect the outgoing edges. */
4218 new_bb
->succs
= bb
->succs
;
4220 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4223 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4226 /* Move everything from BSI to the new basic block. */
4227 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4229 act
= bsi_stmt (bsi
);
4230 if (TREE_CODE (act
) == LABEL_EXPR
)
4243 if (bsi_end_p (bsi
))
4246 /* Split the statement list - avoid re-creating new containers as this
4247 brings ugly quadratic memory consumption in the inliner.
4248 (We are still quadratic since we need to update stmt BB pointers,
4250 new_bb
->stmt_list
= tsi_split_statement_list_before (&bsi
.tsi
);
4251 for (tsi_tgt
= tsi_start (new_bb
->stmt_list
);
4252 !tsi_end_p (tsi_tgt
); tsi_next (&tsi_tgt
))
4253 change_bb_for_stmt (tsi_stmt (tsi_tgt
), new_bb
);
4259 /* Moves basic block BB after block AFTER. */
4262 tree_move_block_after (basic_block bb
, basic_block after
)
4264 if (bb
->prev_bb
== after
)
4268 link_block (bb
, after
);
4274 /* Return true if basic_block can be duplicated. */
4277 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4283 /* Create a duplicate of the basic block BB. NOTE: This does not
4284 preserve SSA form. */
4287 tree_duplicate_bb (basic_block bb
)
4290 block_stmt_iterator bsi
, bsi_tgt
;
4293 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4295 /* Copy the PHI nodes. We ignore PHI node arguments here because
4296 the incoming edges have not been setup yet. */
4297 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4299 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4300 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4303 /* Keep the chain of PHI nodes in the same order so that they can be
4304 updated by ssa_redirect_edge. */
4305 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4307 bsi_tgt
= bsi_start (new_bb
);
4308 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4310 def_operand_p def_p
;
4311 ssa_op_iter op_iter
;
4315 stmt
= bsi_stmt (bsi
);
4316 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4319 /* Create a new copy of STMT and duplicate STMT's virtual
4321 copy
= unshare_expr (stmt
);
4322 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4323 copy_virtual_operands (copy
, stmt
);
4324 region
= lookup_stmt_eh_region (stmt
);
4326 add_stmt_to_eh_region (copy
, region
);
4327 gimple_duplicate_stmt_histograms (cfun
, copy
, cfun
, stmt
);
4329 /* Create new names for all the definitions created by COPY and
4330 add replacement mappings for each new name. */
4331 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4332 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4339 /* Basic block BB_COPY was created by code duplication. Add phi node
4340 arguments for edges going out of BB_COPY. The blocks that were
4341 duplicated have BB_DUPLICATED set. */
4344 add_phi_args_after_copy_bb (basic_block bb_copy
)
4346 basic_block bb
, dest
;
4349 tree phi
, phi_copy
, phi_next
, def
;
4351 bb
= get_bb_original (bb_copy
);
4353 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4355 if (!phi_nodes (e_copy
->dest
))
4358 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4359 dest
= get_bb_original (e_copy
->dest
);
4361 dest
= e_copy
->dest
;
4363 e
= find_edge (bb
, dest
);
4366 /* During loop unrolling the target of the latch edge is copied.
4367 In this case we are not looking for edge to dest, but to
4368 duplicated block whose original was dest. */
4369 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4370 if ((e
->dest
->flags
& BB_DUPLICATED
)
4371 && get_bb_original (e
->dest
) == dest
)
4374 gcc_assert (e
!= NULL
);
4377 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4379 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4381 phi_next
= PHI_CHAIN (phi
);
4382 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4383 add_phi_arg (phi_copy
, def
, e_copy
);
4388 /* Blocks in REGION_COPY array of length N_REGION were created by
4389 duplication of basic blocks. Add phi node arguments for edges
4390 going from these blocks. */
4393 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4397 for (i
= 0; i
< n_region
; i
++)
4398 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4400 for (i
= 0; i
< n_region
; i
++)
4401 add_phi_args_after_copy_bb (region_copy
[i
]);
4403 for (i
= 0; i
< n_region
; i
++)
4404 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4407 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4408 important exit edge EXIT. By important we mean that no SSA name defined
4409 inside region is live over the other exit edges of the region. All entry
4410 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4411 to the duplicate of the region. SSA form, dominance and loop information
4412 is updated. The new basic blocks are stored to REGION_COPY in the same
4413 order as they had in REGION, provided that REGION_COPY is not NULL.
4414 The function returns false if it is unable to copy the region,
4418 tree_duplicate_sese_region (edge entry
, edge exit
,
4419 basic_block
*region
, unsigned n_region
,
4420 basic_block
*region_copy
)
4423 bool free_region_copy
= false, copying_header
= false;
4424 struct loop
*loop
= entry
->dest
->loop_father
;
4428 int total_freq
= 0, entry_freq
= 0;
4429 gcov_type total_count
= 0, entry_count
= 0;
4431 if (!can_copy_bbs_p (region
, n_region
))
4434 /* Some sanity checking. Note that we do not check for all possible
4435 missuses of the functions. I.e. if you ask to copy something weird,
4436 it will work, but the state of structures probably will not be
4438 for (i
= 0; i
< n_region
; i
++)
4440 /* We do not handle subloops, i.e. all the blocks must belong to the
4442 if (region
[i
]->loop_father
!= loop
)
4445 if (region
[i
] != entry
->dest
4446 && region
[i
] == loop
->header
)
4452 /* In case the function is used for loop header copying (which is the primary
4453 use), ensure that EXIT and its copy will be new latch and entry edges. */
4454 if (loop
->header
== entry
->dest
)
4456 copying_header
= true;
4457 loop
->copy
= loop
->outer
;
4459 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4462 for (i
= 0; i
< n_region
; i
++)
4463 if (region
[i
] != exit
->src
4464 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4470 region_copy
= XNEWVEC (basic_block
, n_region
);
4471 free_region_copy
= true;
4474 gcc_assert (!need_ssa_update_p ());
4476 /* Record blocks outside the region that are dominated by something
4478 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4479 initialize_original_copy_tables ();
4481 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4483 if (entry
->dest
->count
)
4485 total_count
= entry
->dest
->count
;
4486 entry_count
= entry
->count
;
4487 /* Fix up corner cases, to avoid division by zero or creation of negative
4489 if (entry_count
> total_count
)
4490 entry_count
= total_count
;
4494 total_freq
= entry
->dest
->frequency
;
4495 entry_freq
= EDGE_FREQUENCY (entry
);
4496 /* Fix up corner cases, to avoid division by zero or creation of negative
4498 if (total_freq
== 0)
4500 else if (entry_freq
> total_freq
)
4501 entry_freq
= total_freq
;
4504 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4505 split_edge_bb_loc (entry
));
4508 scale_bbs_frequencies_gcov_type (region
, n_region
,
4509 total_count
- entry_count
,
4511 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4516 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4518 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4523 loop
->header
= exit
->dest
;
4524 loop
->latch
= exit
->src
;
4527 /* Redirect the entry and add the phi node arguments. */
4528 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4529 gcc_assert (redirected
!= NULL
);
4530 flush_pending_stmts (entry
);
4532 /* Concerning updating of dominators: We must recount dominators
4533 for entry block and its copy. Anything that is outside of the
4534 region, but was dominated by something inside needs recounting as
4536 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4537 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4538 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4541 /* Add the other PHI node arguments. */
4542 add_phi_args_after_copy (region_copy
, n_region
);
4544 /* Update the SSA web. */
4545 update_ssa (TODO_update_ssa
);
4547 if (free_region_copy
)
4550 free_original_copy_tables ();
4555 DEF_VEC_P(basic_block);
4556 DEF_VEC_ALLOC_P(basic_block,heap);
4559 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4560 adding blocks when the dominator traversal reaches EXIT. This
4561 function silently assumes that ENTRY strictly dominates EXIT. */
4564 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4565 VEC(basic_block
,heap
) **bbs_p
)
4569 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4571 son
= next_dom_son (CDI_DOMINATORS
, son
))
4573 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4575 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4585 bitmap vars_to_remove
;
4586 htab_t new_label_map
;
4590 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4591 contained in *TP and change the DECL_CONTEXT of every local
4592 variable referenced in *TP. */
4595 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4597 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4601 && (EXPR_P (t
) || GIMPLE_STMT_P (t
)))
4602 TREE_BLOCK (t
) = p
->block
;
4604 if (OMP_DIRECTIVE_P (t
)
4605 && TREE_CODE (t
) != OMP_RETURN
4606 && TREE_CODE (t
) != OMP_CONTINUE
)
4608 /* Do not remap variables inside OMP directives. Variables
4609 referenced in clauses and directive header belong to the
4610 parent function and should not be moved into the child
4612 bool save_remap_decls_p
= p
->remap_decls_p
;
4613 p
->remap_decls_p
= false;
4616 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4618 p
->remap_decls_p
= save_remap_decls_p
;
4620 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4622 if (TREE_CODE (t
) == LABEL_DECL
)
4624 if (p
->new_label_map
)
4626 struct tree_map in
, *out
;
4628 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4633 DECL_CONTEXT (t
) = p
->to_context
;
4635 else if (p
->remap_decls_p
)
4637 DECL_CONTEXT (t
) = p
->to_context
;
4639 if (TREE_CODE (t
) == VAR_DECL
)
4641 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4642 f
->unexpanded_var_list
4643 = tree_cons (0, t
, f
->unexpanded_var_list
);
4645 /* Mark T to be removed from the original function,
4646 otherwise it will be given a DECL_RTL when the
4647 original function is expanded. */
4648 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4652 else if (TYPE_P (t
))
4659 /* Move basic block BB from function CFUN to function DEST_FN. The
4660 block is moved out of the original linked list and placed after
4661 block AFTER in the new list. Also, the block is removed from the
4662 original array of blocks and placed in DEST_FN's array of blocks.
4663 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4664 updated to reflect the moved edges.
4666 On exit, local variables that need to be removed from
4667 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4670 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4671 basic_block after
, bool update_edge_count_p
,
4672 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4674 struct control_flow_graph
*cfg
;
4677 block_stmt_iterator si
;
4678 struct move_stmt_d d
;
4679 unsigned old_len
, new_len
;
4681 /* Link BB to the new linked list. */
4682 move_block_after (bb
, after
);
4684 /* Update the edge count in the corresponding flowgraphs. */
4685 if (update_edge_count_p
)
4686 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4688 cfun
->cfg
->x_n_edges
--;
4689 dest_cfun
->cfg
->x_n_edges
++;
4692 /* Remove BB from the original basic block array. */
4693 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4694 cfun
->cfg
->x_n_basic_blocks
--;
4696 /* Grow DEST_CFUN's basic block array if needed. */
4697 cfg
= dest_cfun
->cfg
;
4698 cfg
->x_n_basic_blocks
++;
4699 if (bb
->index
> cfg
->x_last_basic_block
)
4700 cfg
->x_last_basic_block
= bb
->index
;
4702 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4703 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4705 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4706 VEC_safe_grow_cleared (basic_block
, gc
, cfg
->x_basic_block_info
,
4710 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4711 cfg
->x_last_basic_block
, bb
);
4713 /* The statements in BB need to be associated with a new TREE_BLOCK.
4714 Labels need to be associated with a new label-to-block map. */
4715 memset (&d
, 0, sizeof (d
));
4716 d
.vars_to_remove
= vars_to_remove
;
4718 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4720 tree stmt
= bsi_stmt (si
);
4723 d
.from_context
= cfun
->decl
;
4724 d
.to_context
= dest_cfun
->decl
;
4725 d
.remap_decls_p
= true;
4726 d
.new_label_map
= new_label_map
;
4727 if (TREE_BLOCK (stmt
))
4728 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4730 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4732 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4734 tree label
= LABEL_EXPR_LABEL (stmt
);
4735 int uid
= LABEL_DECL_UID (label
);
4737 gcc_assert (uid
> -1);
4739 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4740 if (old_len
<= (unsigned) uid
)
4742 new_len
= 3 * uid
/ 2;
4743 VEC_safe_grow_cleared (basic_block
, gc
,
4744 cfg
->x_label_to_block_map
, new_len
);
4747 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4748 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4750 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4752 if (uid
>= dest_cfun
->last_label_uid
)
4753 dest_cfun
->last_label_uid
= uid
+ 1;
4755 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4756 TREE_OPERAND (stmt
, 0) =
4757 build_int_cst (NULL_TREE
,
4758 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4761 region
= lookup_stmt_eh_region (stmt
);
4764 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4765 remove_stmt_from_eh_region (stmt
);
4766 gimple_duplicate_stmt_histograms (dest_cfun
, stmt
, cfun
, stmt
);
4767 gimple_remove_stmt_histograms (cfun
, stmt
);
4772 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4773 the outermost EH region. Use REGION as the incoming base EH region. */
4776 find_outermost_region_in_block (struct function
*src_cfun
,
4777 basic_block bb
, int region
)
4779 block_stmt_iterator si
;
4781 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4783 tree stmt
= bsi_stmt (si
);
4786 if (TREE_CODE (stmt
) == RESX_EXPR
)
4787 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4789 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4790 if (stmt_region
> 0)
4793 region
= stmt_region
;
4794 else if (stmt_region
!= region
)
4796 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4797 gcc_assert (region
!= -1);
4806 new_label_mapper (tree decl
, void *data
)
4808 htab_t hash
= (htab_t
) data
;
4812 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4814 m
= xmalloc (sizeof (struct tree_map
));
4815 m
->hash
= DECL_UID (decl
);
4817 m
->to
= create_artificial_label ();
4818 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4820 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4821 gcc_assert (*slot
== NULL
);
4828 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4829 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4830 single basic block in the original CFG and the new basic block is
4831 returned. DEST_CFUN must not have a CFG yet.
4833 Note that the region need not be a pure SESE region. Blocks inside
4834 the region may contain calls to abort/exit. The only restriction
4835 is that ENTRY_BB should be the only entry point and it must
4838 All local variables referenced in the region are assumed to be in
4839 the corresponding BLOCK_VARS and unexpanded variable lists
4840 associated with DEST_CFUN. */
4843 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4844 basic_block exit_bb
)
4846 VEC(basic_block
,heap
) *bbs
;
4847 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4848 struct function
*saved_cfun
;
4849 int *entry_flag
, *exit_flag
, eh_offset
;
4850 unsigned i
, num_entry_edges
, num_exit_edges
;
4853 bitmap vars_to_remove
;
4854 htab_t new_label_map
;
4858 /* Collect all the blocks in the region. Manually add ENTRY_BB
4859 because it won't be added by dfs_enumerate_from. */
4860 calculate_dominance_info (CDI_DOMINATORS
);
4862 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4864 gcc_assert (entry_bb
!= exit_bb
4866 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4869 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4870 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4872 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4873 the predecessor edges to ENTRY_BB and the successor edges to
4874 EXIT_BB so that we can re-attach them to the new basic block that
4875 will replace the region. */
4876 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4877 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4878 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4880 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4882 entry_flag
[i
] = e
->flags
;
4883 entry_pred
[i
++] = e
->src
;
4889 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4890 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4891 sizeof (basic_block
));
4892 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4894 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4896 exit_flag
[i
] = e
->flags
;
4897 exit_succ
[i
++] = e
->dest
;
4908 /* Switch context to the child function to initialize DEST_FN's CFG. */
4909 gcc_assert (dest_cfun
->cfg
== NULL
);
4912 init_empty_tree_cfg ();
4914 /* Initialize EH information for the new function. */
4916 new_label_map
= NULL
;
4921 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4922 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4924 init_eh_for_function ();
4927 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4928 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4929 new_label_map
, region
, 0);
4935 /* Move blocks from BBS into DEST_CFUN. */
4936 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4937 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4938 vars_to_remove
= BITMAP_ALLOC (NULL
);
4939 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4941 /* No need to update edge counts on the last block. It has
4942 already been updated earlier when we detached the region from
4943 the original CFG. */
4944 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4945 new_label_map
, eh_offset
);
4950 htab_delete (new_label_map
);
4952 /* Remove the variables marked in VARS_TO_REMOVE from
4953 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4954 DECL_RTL in the context of CFUN. */
4955 if (!bitmap_empty_p (vars_to_remove
))
4959 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4961 tree var
= TREE_VALUE (*p
);
4962 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4964 *p
= TREE_CHAIN (*p
);
4968 p
= &TREE_CHAIN (*p
);
4972 BITMAP_FREE (vars_to_remove
);
4974 /* Rewire the entry and exit blocks. The successor to the entry
4975 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4976 the child function. Similarly, the predecessor of DEST_FN's
4977 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4978 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4979 various CFG manipulation function get to the right CFG.
4981 FIXME, this is silly. The CFG ought to become a parameter to
4984 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4986 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4989 /* Back in the original function, the SESE region has disappeared,
4990 create a new basic block in its place. */
4991 bb
= create_empty_bb (entry_pred
[0]);
4992 for (i
= 0; i
< num_entry_edges
; i
++)
4993 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4995 for (i
= 0; i
< num_exit_edges
; i
++)
4996 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
5005 free_dominance_info (CDI_DOMINATORS
);
5006 free_dominance_info (CDI_POST_DOMINATORS
);
5007 VEC_free (basic_block
, heap
, bbs
);
5013 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5016 dump_function_to_file (tree fn
, FILE *file
, int flags
)
5018 tree arg
, vars
, var
;
5019 bool ignore_topmost_bind
= false, any_var
= false;
5022 struct function
*saved_cfun
;
5024 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5026 arg
= DECL_ARGUMENTS (fn
);
5029 print_generic_expr (file
, arg
, dump_flags
);
5030 if (TREE_CHAIN (arg
))
5031 fprintf (file
, ", ");
5032 arg
= TREE_CHAIN (arg
);
5034 fprintf (file
, ")\n");
5036 if (flags
& TDF_DETAILS
)
5037 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
5038 if (flags
& TDF_RAW
)
5040 dump_node (fn
, TDF_SLIM
| flags
, file
);
5044 /* Switch CFUN to point to FN. */
5046 cfun
= DECL_STRUCT_FUNCTION (fn
);
5048 /* When GIMPLE is lowered, the variables are no longer available in
5049 BIND_EXPRs, so display them separately. */
5050 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5052 ignore_topmost_bind
= true;
5054 fprintf (file
, "{\n");
5055 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5057 var
= TREE_VALUE (vars
);
5059 print_generic_decl (file
, var
, flags
);
5060 fprintf (file
, "\n");
5066 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5068 /* Make a CFG based dump. */
5069 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5070 if (!ignore_topmost_bind
)
5071 fprintf (file
, "{\n");
5073 if (any_var
&& n_basic_blocks
)
5074 fprintf (file
, "\n");
5077 dump_generic_bb (file
, bb
, 2, flags
);
5079 fprintf (file
, "}\n");
5080 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5086 /* Make a tree based dump. */
5087 chain
= DECL_SAVED_TREE (fn
);
5089 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5091 if (ignore_topmost_bind
)
5093 chain
= BIND_EXPR_BODY (chain
);
5101 if (!ignore_topmost_bind
)
5102 fprintf (file
, "{\n");
5107 fprintf (file
, "\n");
5109 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5110 if (ignore_topmost_bind
)
5111 fprintf (file
, "}\n");
5114 fprintf (file
, "\n\n");
5121 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5124 debug_function (tree fn
, int flags
)
5126 dump_function_to_file (fn
, stderr
, flags
);
5130 /* Pretty print of the loops intermediate representation. */
5131 static void print_loop (FILE *, struct loop
*, int);
5132 static void print_pred_bbs (FILE *, basic_block bb
);
5133 static void print_succ_bbs (FILE *, basic_block bb
);
5136 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5139 print_pred_bbs (FILE *file
, basic_block bb
)
5144 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5145 fprintf (file
, "bb_%d ", e
->src
->index
);
5149 /* Print on FILE the indexes for the successors of basic_block BB. */
5152 print_succ_bbs (FILE *file
, basic_block bb
)
5157 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5158 fprintf (file
, "bb_%d ", e
->dest
->index
);
5162 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5165 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5173 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5174 memset ((void *) s_indent
, ' ', (size_t) indent
);
5175 s_indent
[indent
] = '\0';
5177 /* Print the loop's header. */
5178 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5180 /* Print the loop's body. */
5181 fprintf (file
, "%s{\n", s_indent
);
5183 if (bb
->loop_father
== loop
)
5185 /* Print the basic_block's header. */
5186 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5187 print_pred_bbs (file
, bb
);
5188 fprintf (file
, "}, succs = {");
5189 print_succ_bbs (file
, bb
);
5190 fprintf (file
, "})\n");
5192 /* Print the basic_block's body. */
5193 fprintf (file
, "%s {\n", s_indent
);
5194 tree_dump_bb (bb
, file
, indent
+ 4);
5195 fprintf (file
, "%s }\n", s_indent
);
5198 print_loop (file
, loop
->inner
, indent
+ 2);
5199 fprintf (file
, "%s}\n", s_indent
);
5200 print_loop (file
, loop
->next
, indent
);
5204 /* Follow a CFG edge from the entry point of the program, and on entry
5205 of a loop, pretty print the loop structure on FILE. */
5208 print_loop_ir (FILE *file
)
5212 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5213 if (bb
&& bb
->loop_father
)
5214 print_loop (file
, bb
->loop_father
, 0);
5218 /* Debugging loops structure at tree level. */
5221 debug_loop_ir (void)
5223 print_loop_ir (stderr
);
5227 /* Return true if BB ends with a call, possibly followed by some
5228 instructions that must stay with the call. Return false,
5232 tree_block_ends_with_call_p (basic_block bb
)
5234 block_stmt_iterator bsi
= bsi_last (bb
);
5235 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5239 /* Return true if BB ends with a conditional branch. Return false,
5243 tree_block_ends_with_condjump_p (basic_block bb
)
5245 tree stmt
= last_stmt (bb
);
5246 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5250 /* Return true if we need to add fake edge to exit at statement T.
5251 Helper function for tree_flow_call_edges_add. */
5254 need_fake_edge_p (tree t
)
5258 /* NORETURN and LONGJMP calls already have an edge to exit.
5259 CONST and PURE calls do not need one.
5260 We don't currently check for CONST and PURE here, although
5261 it would be a good idea, because those attributes are
5262 figured out from the RTL in mark_constant_function, and
5263 the counter incrementation code from -fprofile-arcs
5264 leads to different results from -fbranch-probabilities. */
5265 call
= get_call_expr_in (t
);
5267 && !(call_expr_flags (call
) & ECF_NORETURN
))
5270 if (TREE_CODE (t
) == ASM_EXPR
5271 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5278 /* Add fake edges to the function exit for any non constant and non
5279 noreturn calls, volatile inline assembly in the bitmap of blocks
5280 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5281 the number of blocks that were split.
5283 The goal is to expose cases in which entering a basic block does
5284 not imply that all subsequent instructions must be executed. */
5287 tree_flow_call_edges_add (sbitmap blocks
)
5290 int blocks_split
= 0;
5291 int last_bb
= last_basic_block
;
5292 bool check_last_block
= false;
5294 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5298 check_last_block
= true;
5300 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5302 /* In the last basic block, before epilogue generation, there will be
5303 a fallthru edge to EXIT. Special care is required if the last insn
5304 of the last basic block is a call because make_edge folds duplicate
5305 edges, which would result in the fallthru edge also being marked
5306 fake, which would result in the fallthru edge being removed by
5307 remove_fake_edges, which would result in an invalid CFG.
5309 Moreover, we can't elide the outgoing fake edge, since the block
5310 profiler needs to take this into account in order to solve the minimal
5311 spanning tree in the case that the call doesn't return.
5313 Handle this by adding a dummy instruction in a new last basic block. */
5314 if (check_last_block
)
5316 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5317 block_stmt_iterator bsi
= bsi_last (bb
);
5319 if (!bsi_end_p (bsi
))
5322 if (t
&& need_fake_edge_p (t
))
5326 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5329 bsi_insert_on_edge (e
, build_empty_stmt ());
5330 bsi_commit_edge_inserts ();
5335 /* Now add fake edges to the function exit for any non constant
5336 calls since there is no way that we can determine if they will
5338 for (i
= 0; i
< last_bb
; i
++)
5340 basic_block bb
= BASIC_BLOCK (i
);
5341 block_stmt_iterator bsi
;
5342 tree stmt
, last_stmt
;
5347 if (blocks
&& !TEST_BIT (blocks
, i
))
5350 bsi
= bsi_last (bb
);
5351 if (!bsi_end_p (bsi
))
5353 last_stmt
= bsi_stmt (bsi
);
5356 stmt
= bsi_stmt (bsi
);
5357 if (need_fake_edge_p (stmt
))
5360 /* The handling above of the final block before the
5361 epilogue should be enough to verify that there is
5362 no edge to the exit block in CFG already.
5363 Calling make_edge in such case would cause us to
5364 mark that edge as fake and remove it later. */
5365 #ifdef ENABLE_CHECKING
5366 if (stmt
== last_stmt
)
5368 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5369 gcc_assert (e
== NULL
);
5373 /* Note that the following may create a new basic block
5374 and renumber the existing basic blocks. */
5375 if (stmt
!= last_stmt
)
5377 e
= split_block (bb
, stmt
);
5381 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5385 while (!bsi_end_p (bsi
));
5390 verify_flow_info ();
5392 return blocks_split
;
5395 /* Purge dead abnormal call edges from basic block BB. */
5398 tree_purge_dead_abnormal_call_edges (basic_block bb
)
5400 bool changed
= tree_purge_dead_eh_edges (bb
);
5402 if (current_function_has_nonlocal_label
)
5404 tree stmt
= last_stmt (bb
);
5408 if (!(stmt
&& tree_can_make_abnormal_goto (stmt
)))
5409 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5411 if (e
->flags
& EDGE_ABNORMAL
)
5420 /* See tree_purge_dead_eh_edges below. */
5422 free_dominance_info (CDI_DOMINATORS
);
5428 /* Purge dead EH edges from basic block BB. */
5431 tree_purge_dead_eh_edges (basic_block bb
)
5433 bool changed
= false;
5436 tree stmt
= last_stmt (bb
);
5438 if (stmt
&& tree_can_throw_internal (stmt
))
5441 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5443 if (e
->flags
& EDGE_EH
)
5452 /* Removal of dead EH edges might change dominators of not
5453 just immediate successors. E.g. when bb1 is changed so that
5454 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5455 eh edges purged by this function in:
5467 idom(bb5) must be recomputed. For now just free the dominance
5470 free_dominance_info (CDI_DOMINATORS
);
5476 tree_purge_all_dead_eh_edges (bitmap blocks
)
5478 bool changed
= false;
5482 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5484 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5490 /* This function is called whenever a new edge is created or
5494 tree_execute_on_growing_pred (edge e
)
5496 basic_block bb
= e
->dest
;
5499 reserve_phi_args_for_new_edge (bb
);
5502 /* This function is called immediately before edge E is removed from
5503 the edge vector E->dest->preds. */
5506 tree_execute_on_shrinking_pred (edge e
)
5508 if (phi_nodes (e
->dest
))
5509 remove_phi_args (e
);
5512 /*---------------------------------------------------------------------------
5513 Helper functions for Loop versioning
5514 ---------------------------------------------------------------------------*/
5516 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5517 of 'first'. Both of them are dominated by 'new_head' basic block. When
5518 'new_head' was created by 'second's incoming edge it received phi arguments
5519 on the edge by split_edge(). Later, additional edge 'e' was created to
5520 connect 'new_head' and 'first'. Now this routine adds phi args on this
5521 additional edge 'e' that new_head to second edge received as part of edge
5526 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5527 basic_block new_head
, edge e
)
5530 edge e2
= find_edge (new_head
, second
);
5532 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5533 edge, we should always have an edge from NEW_HEAD to SECOND. */
5534 gcc_assert (e2
!= NULL
);
5536 /* Browse all 'second' basic block phi nodes and add phi args to
5537 edge 'e' for 'first' head. PHI args are always in correct order. */
5539 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5541 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5543 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5544 add_phi_arg (phi1
, def
, e
);
5548 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5549 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5550 the destination of the ELSE part. */
5552 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5553 basic_block cond_bb
, void *cond_e
)
5555 block_stmt_iterator bsi
;
5556 tree goto1
= NULL_TREE
;
5557 tree goto2
= NULL_TREE
;
5558 tree new_cond_expr
= NULL_TREE
;
5559 tree cond_expr
= (tree
) cond_e
;
5562 /* Build new conditional expr */
5563 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5564 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5565 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5567 /* Add new cond in cond_bb. */
5568 bsi
= bsi_start (cond_bb
);
5569 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5570 /* Adjust edges appropriately to connect new head with first head
5571 as well as second head. */
5572 e0
= single_succ_edge (cond_bb
);
5573 e0
->flags
&= ~EDGE_FALLTHRU
;
5574 e0
->flags
|= EDGE_FALSE_VALUE
;
5577 struct cfg_hooks tree_cfg_hooks
= {
5579 tree_verify_flow_info
,
5580 tree_dump_bb
, /* dump_bb */
5581 create_bb
, /* create_basic_block */
5582 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5583 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5584 remove_bb
, /* delete_basic_block */
5585 tree_split_block
, /* split_block */
5586 tree_move_block_after
, /* move_block_after */
5587 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5588 tree_merge_blocks
, /* merge_blocks */
5589 tree_predict_edge
, /* predict_edge */
5590 tree_predicted_by_p
, /* predicted_by_p */
5591 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5592 tree_duplicate_bb
, /* duplicate_block */
5593 tree_split_edge
, /* split_edge */
5594 tree_make_forwarder_block
, /* make_forward_block */
5595 NULL
, /* tidy_fallthru_edge */
5596 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5597 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5598 tree_flow_call_edges_add
, /* flow_call_edges_add */
5599 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5600 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5601 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5602 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5603 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5604 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5605 flush_pending_stmts
/* flush_pending_stmts */
5609 /* Split all critical edges. */
5612 split_critical_edges (void)
5618 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5619 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5620 mappings around the calls to split_edge. */
5621 start_recording_case_labels ();
5624 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5625 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5630 end_recording_case_labels ();
5634 struct tree_opt_pass pass_split_crit_edges
=
5636 "crited", /* name */
5638 split_critical_edges
, /* execute */
5641 0, /* static_pass_number */
5642 TV_TREE_SPLIT_EDGES
, /* tv_id */
5643 PROP_cfg
, /* properties required */
5644 PROP_no_crit_edges
, /* properties_provided */
5645 0, /* properties_destroyed */
5646 0, /* todo_flags_start */
5647 TODO_dump_func
, /* todo_flags_finish */
5652 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5653 a temporary, make sure and register it to be renamed if necessary,
5654 and finally return the temporary. Put the statements to compute
5655 EXP before the current statement in BSI. */
5658 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5660 tree t
, new_stmt
, orig_stmt
;
5662 if (is_gimple_val (exp
))
5665 t
= make_rename_temp (type
, NULL
);
5666 new_stmt
= build2_gimple (GIMPLE_MODIFY_STMT
, t
, exp
);
5668 orig_stmt
= bsi_stmt (*bsi
);
5669 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5670 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5672 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5673 if (gimple_in_ssa_p (cfun
))
5674 mark_symbols_for_renaming (new_stmt
);
5679 /* Build a ternary operation and gimplify it. Emit code before BSI.
5680 Return the gimple_val holding the result. */
5683 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5684 tree type
, tree a
, tree b
, tree c
)
5688 ret
= fold_build3 (code
, type
, a
, b
, c
);
5691 return gimplify_val (bsi
, type
, ret
);
5694 /* Build a binary operation and gimplify it. Emit code before BSI.
5695 Return the gimple_val holding the result. */
5698 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5699 tree type
, tree a
, tree b
)
5703 ret
= fold_build2 (code
, type
, a
, b
);
5706 return gimplify_val (bsi
, type
, ret
);
5709 /* Build a unary operation and gimplify it. Emit code before BSI.
5710 Return the gimple_val holding the result. */
5713 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5718 ret
= fold_build1 (code
, type
, a
);
5721 return gimplify_val (bsi
, type
, ret
);
5726 /* Emit return warnings. */
5729 execute_warn_function_return (void)
5731 #ifdef USE_MAPPED_LOCATION
5732 source_location location
;
5740 /* If we have a path to EXIT, then we do return. */
5741 if (TREE_THIS_VOLATILE (cfun
->decl
)
5742 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5744 #ifdef USE_MAPPED_LOCATION
5745 location
= UNKNOWN_LOCATION
;
5749 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5751 last
= last_stmt (e
->src
);
5752 if (TREE_CODE (last
) == RETURN_EXPR
5753 #ifdef USE_MAPPED_LOCATION
5754 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5756 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5760 #ifdef USE_MAPPED_LOCATION
5761 if (location
== UNKNOWN_LOCATION
)
5762 location
= cfun
->function_end_locus
;
5763 warning (0, "%H%<noreturn%> function does return", &location
);
5766 locus
= &cfun
->function_end_locus
;
5767 warning (0, "%H%<noreturn%> function does return", locus
);
5771 /* If we see "return;" in some basic block, then we do reach the end
5772 without returning a value. */
5773 else if (warn_return_type
5774 && !TREE_NO_WARNING (cfun
->decl
)
5775 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5776 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5778 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5780 tree last
= last_stmt (e
->src
);
5781 if (TREE_CODE (last
) == RETURN_EXPR
5782 && TREE_OPERAND (last
, 0) == NULL
5783 && !TREE_NO_WARNING (last
))
5785 #ifdef USE_MAPPED_LOCATION
5786 location
= EXPR_LOCATION (last
);
5787 if (location
== UNKNOWN_LOCATION
)
5788 location
= cfun
->function_end_locus
;
5789 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5791 locus
= EXPR_LOCUS (last
);
5793 locus
= &cfun
->function_end_locus
;
5794 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5796 TREE_NO_WARNING (cfun
->decl
) = 1;
5805 /* Given a basic block B which ends with a conditional and has
5806 precisely two successors, determine which of the edges is taken if
5807 the conditional is true and which is taken if the conditional is
5808 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5811 extract_true_false_edges_from_block (basic_block b
,
5815 edge e
= EDGE_SUCC (b
, 0);
5817 if (e
->flags
& EDGE_TRUE_VALUE
)
5820 *false_edge
= EDGE_SUCC (b
, 1);
5825 *true_edge
= EDGE_SUCC (b
, 1);
5829 struct tree_opt_pass pass_warn_function_return
=
5833 execute_warn_function_return
, /* execute */
5836 0, /* static_pass_number */
5838 PROP_cfg
, /* properties_required */
5839 0, /* properties_provided */
5840 0, /* properties_destroyed */
5841 0, /* todo_flags_start */
5842 0, /* todo_flags_finish */
5846 /* Emit noreturn warnings. */
5849 execute_warn_function_noreturn (void)
5851 if (warn_missing_noreturn
5852 && !TREE_THIS_VOLATILE (cfun
->decl
)
5853 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5854 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5855 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5856 "for attribute %<noreturn%>",
5861 struct tree_opt_pass pass_warn_function_noreturn
=
5865 execute_warn_function_noreturn
, /* execute */
5868 0, /* static_pass_number */
5870 PROP_cfg
, /* properties_required */
5871 0, /* properties_provided */
5872 0, /* properties_destroyed */
5873 0, /* todo_flags_start */
5874 0, /* todo_flags_finish */