1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
48 #include "tree-ssa-propagate.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity
= 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 struct edge_to_cases_elt
73 /* The edge itself. Necessary for hashing and equality tests. */
76 /* The case labels associated with this edge. We link these up via
77 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
78 when we destroy the hash table. This prevents problems when copying
83 static htab_t edge_to_cases
;
88 long num_merged_labels
;
91 static struct cfg_stats_d cfg_stats
;
93 /* Nonzero if we found a computed goto while building basic blocks. */
94 static bool found_computed_goto
;
96 /* Basic blocks and flowgraphs. */
97 static basic_block
create_bb (void *, void *, basic_block
);
98 static void make_blocks (tree
);
99 static void factor_computed_gotos (void);
102 static void make_edges (void);
103 static void make_cond_expr_edges (basic_block
);
104 static void make_switch_expr_edges (basic_block
);
105 static void make_goto_expr_edges (basic_block
);
106 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
107 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
108 static unsigned int split_critical_edges (void);
110 /* Various helpers. */
111 static inline bool stmt_starts_bb_p (tree
, tree
);
112 static int tree_verify_flow_info (void);
113 static void tree_make_forwarder_block (edge
);
114 static void tree_cfg2vcg (FILE *);
116 /* Flowgraph optimization and cleanup. */
117 static void tree_merge_blocks (basic_block
, basic_block
);
118 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
119 static void remove_bb (basic_block
);
120 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
121 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
122 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
123 static tree
find_case_label_for_value (tree
, tree
);
126 init_empty_tree_cfg (void)
128 /* Initialize the basic block array. */
130 profile_status
= PROFILE_ABSENT
;
131 n_basic_blocks
= NUM_FIXED_BLOCKS
;
132 last_basic_block
= NUM_FIXED_BLOCKS
;
133 basic_block_info
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
134 VEC_safe_grow (basic_block
, gc
, basic_block_info
, initial_cfg_capacity
);
135 memset (VEC_address (basic_block
, basic_block_info
), 0,
136 sizeof (basic_block
) * initial_cfg_capacity
);
138 /* Build a mapping of labels to their associated blocks. */
139 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
140 VEC_safe_grow (basic_block
, gc
, label_to_block_map
, initial_cfg_capacity
);
141 memset (VEC_address (basic_block
, label_to_block_map
),
142 0, sizeof (basic_block
) * 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
)
185 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
187 VEC_safe_grow (basic_block
, gc
, basic_block_info
, n_basic_blocks
);
188 p
= VEC_address (basic_block
, basic_block_info
);
189 memset (&p
[old_size
], 0,
190 sizeof (basic_block
) * (n_basic_blocks
- old_size
));
193 /* To speed up statement iterator walks, we first purge dead labels. */
194 cleanup_dead_labels ();
196 /* Group case nodes to reduce the number of edges.
197 We do this after cleaning up dead labels because otherwise we miss
198 a lot of obvious case merging opportunities. */
199 group_case_labels ();
201 /* Create the edges of the flowgraph. */
204 /* Debugging dumps. */
206 /* Write the flowgraph to a VCG file. */
208 int local_dump_flags
;
209 FILE *vcg_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
212 tree_cfg2vcg (vcg_file
);
213 dump_end (TDI_vcg
, vcg_file
);
217 #ifdef ENABLE_CHECKING
221 /* Dump a textual representation of the flowgraph. */
223 dump_tree_cfg (dump_file
, dump_flags
);
227 execute_build_cfg (void)
229 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
233 struct tree_opt_pass pass_build_cfg
=
237 execute_build_cfg
, /* execute */
240 0, /* static_pass_number */
241 TV_TREE_CFG
, /* tv_id */
242 PROP_gimple_leh
, /* properties_required */
243 PROP_cfg
, /* properties_provided */
244 0, /* properties_destroyed */
245 0, /* todo_flags_start */
246 TODO_verify_stmts
, /* todo_flags_finish */
250 /* Search the CFG for any computed gotos. If found, factor them to a
251 common computed goto site. Also record the location of that site so
252 that we can un-factor the gotos after we have converted back to
256 factor_computed_gotos (void)
259 tree factored_label_decl
= NULL
;
261 tree factored_computed_goto_label
= NULL
;
262 tree factored_computed_goto
= NULL
;
264 /* We know there are one or more computed gotos in this function.
265 Examine the last statement in each basic block to see if the block
266 ends with a computed goto. */
270 block_stmt_iterator bsi
= bsi_last (bb
);
275 last
= bsi_stmt (bsi
);
277 /* Ignore the computed goto we create when we factor the original
279 if (last
== factored_computed_goto
)
282 /* If the last statement is a computed goto, factor it. */
283 if (computed_goto_p (last
))
287 /* The first time we find a computed goto we need to create
288 the factored goto block and the variable each original
289 computed goto will use for their goto destination. */
290 if (! factored_computed_goto
)
292 basic_block new_bb
= create_empty_bb (bb
);
293 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
295 /* Create the destination of the factored goto. Each original
296 computed goto will put its desired destination into this
297 variable and jump to the label we create immediately
299 var
= create_tmp_var (ptr_type_node
, "gotovar");
301 /* Build a label for the new block which will contain the
302 factored computed goto. */
303 factored_label_decl
= create_artificial_label ();
304 factored_computed_goto_label
305 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
306 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
309 /* Build our new computed goto. */
310 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
311 bsi_insert_after (&new_bsi
, factored_computed_goto
,
315 /* Copy the original computed goto's destination into VAR. */
316 assignment
= build2 (MODIFY_EXPR
, ptr_type_node
,
317 var
, GOTO_DESTINATION (last
));
318 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
320 /* And re-vector the computed goto to the new destination. */
321 GOTO_DESTINATION (last
) = factored_label_decl
;
327 /* Build a flowgraph for the statement_list STMT_LIST. */
330 make_blocks (tree stmt_list
)
332 tree_stmt_iterator i
= tsi_start (stmt_list
);
334 bool start_new_block
= true;
335 bool first_stmt_of_list
= true;
336 basic_block bb
= ENTRY_BLOCK_PTR
;
338 while (!tsi_end_p (i
))
345 /* If the statement starts a new basic block or if we have determined
346 in a previous pass that we need to create a new block for STMT, do
348 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
350 if (!first_stmt_of_list
)
351 stmt_list
= tsi_split_statement_list_before (&i
);
352 bb
= create_basic_block (stmt_list
, NULL
, bb
);
353 start_new_block
= false;
356 /* Now add STMT to BB and create the subgraphs for special statement
358 set_bb_for_stmt (stmt
, bb
);
360 if (computed_goto_p (stmt
))
361 found_computed_goto
= true;
363 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
365 if (stmt_ends_bb_p (stmt
))
366 start_new_block
= true;
369 first_stmt_of_list
= false;
374 /* Create and return a new empty basic block after bb AFTER. */
377 create_bb (void *h
, void *e
, basic_block after
)
383 /* Create and initialize a new basic block. Since alloc_block uses
384 ggc_alloc_cleared to allocate a basic block, we do not have to
385 clear the newly allocated basic block here. */
388 bb
->index
= last_basic_block
;
390 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
392 /* Add the new block to the linked list of blocks. */
393 link_block (bb
, after
);
395 /* Grow the basic block array if needed. */
396 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
398 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
399 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
401 VEC_safe_grow (basic_block
, gc
, basic_block_info
, new_size
);
402 p
= VEC_address (basic_block
, basic_block_info
);
403 memset (&p
[old_size
], 0, sizeof (basic_block
) * (new_size
- old_size
));
406 /* Add the newly created block to the array. */
407 SET_BASIC_BLOCK (last_basic_block
, bb
);
416 /*---------------------------------------------------------------------------
418 ---------------------------------------------------------------------------*/
420 /* Fold COND_EXPR_COND of each COND_EXPR. */
423 fold_cond_expr_cond (void)
429 tree stmt
= last_stmt (bb
);
432 && TREE_CODE (stmt
) == COND_EXPR
)
434 tree cond
= fold (COND_EXPR_COND (stmt
));
435 if (integer_zerop (cond
))
436 COND_EXPR_COND (stmt
) = boolean_false_node
;
437 else if (integer_onep (cond
))
438 COND_EXPR_COND (stmt
) = boolean_true_node
;
443 /* Join all the blocks in the flowgraph. */
449 struct omp_region
*cur_region
= NULL
;
451 /* Create an edge from entry to the first block with executable
453 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
455 /* Traverse the basic block array placing edges. */
458 tree last
= last_stmt (bb
);
463 enum tree_code code
= TREE_CODE (last
);
467 make_goto_expr_edges (bb
);
471 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
475 make_cond_expr_edges (bb
);
479 make_switch_expr_edges (bb
);
483 make_eh_edges (last
);
488 /* If this function receives a nonlocal goto, then we need to
489 make edges from this call site to all the nonlocal goto
491 if (TREE_SIDE_EFFECTS (last
)
492 && current_function_has_nonlocal_label
)
493 make_goto_expr_edges (bb
);
495 /* If this statement has reachable exception handlers, then
496 create abnormal edges to them. */
497 make_eh_edges (last
);
499 /* Some calls are known not to return. */
500 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
504 if (is_ctrl_altering_stmt (last
))
506 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
507 CALL_EXPR may have an abnormal edge. Search the RHS for
508 this case and create any required edges. */
509 tree op
= get_call_expr_in (last
);
510 if (op
&& TREE_SIDE_EFFECTS (op
)
511 && current_function_has_nonlocal_label
)
512 make_goto_expr_edges (bb
);
514 make_eh_edges (last
);
526 cur_region
= new_omp_region (bb
, code
, cur_region
);
531 cur_region
= new_omp_region (bb
, code
, cur_region
);
536 /* In the case of an OMP_SECTION, the edge will go somewhere
537 other than the next block. This will be created later. */
538 cur_region
->exit
= bb
;
539 fallthru
= cur_region
->type
!= OMP_SECTION
;
540 cur_region
= cur_region
->outer
;
544 cur_region
->cont
= bb
;
545 switch (cur_region
->type
)
548 /* ??? Technically there should be a some sort of loopback
549 edge here, but it goes to a block that doesn't exist yet,
550 and without it, updating the ssa form would be a real
551 bear. Fortunately, we don't yet do ssa before expanding
556 /* Wire up the edges into and out of the nested sections. */
557 /* ??? Similarly wrt loopback. */
559 struct omp_region
*i
;
560 for (i
= cur_region
->inner
; i
; i
= i
->next
)
562 gcc_assert (i
->type
== OMP_SECTION
);
563 make_edge (cur_region
->entry
, i
->entry
, 0);
564 make_edge (i
->exit
, bb
, EDGE_FALLTHRU
);
576 gcc_assert (!stmt_ends_bb_p (last
));
584 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
590 /* Fold COND_EXPR_COND of each COND_EXPR. */
591 fold_cond_expr_cond ();
593 /* Clean up the graph and warn for unreachable code. */
598 /* Create the edges for a COND_EXPR starting at block BB.
599 At this point, both clauses must contain only simple gotos. */
602 make_cond_expr_edges (basic_block bb
)
604 tree entry
= last_stmt (bb
);
605 basic_block then_bb
, else_bb
;
606 tree then_label
, else_label
;
610 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
612 /* Entry basic blocks for each component. */
613 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
614 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
615 then_bb
= label_to_block (then_label
);
616 else_bb
= label_to_block (else_label
);
618 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
619 #ifdef USE_MAPPED_LOCATION
620 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
622 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
624 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
627 #ifdef USE_MAPPED_LOCATION
628 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
630 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
635 /* Hashing routine for EDGE_TO_CASES. */
638 edge_to_cases_hash (const void *p
)
640 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
642 /* Hash on the edge itself (which is a pointer). */
643 return htab_hash_pointer (e
);
646 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
647 for equality is just a pointer comparison. */
650 edge_to_cases_eq (const void *p1
, const void *p2
)
652 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
653 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
658 /* Called for each element in the hash table (P) as we delete the
659 edge to cases hash table.
661 Clear all the TREE_CHAINs to prevent problems with copying of
662 SWITCH_EXPRs and structure sharing rules, then free the hash table
666 edge_to_cases_cleanup (void *p
)
668 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
671 for (t
= elt
->case_labels
; t
; t
= next
)
673 next
= TREE_CHAIN (t
);
674 TREE_CHAIN (t
) = NULL
;
679 /* Start recording information mapping edges to case labels. */
682 start_recording_case_labels (void)
684 gcc_assert (edge_to_cases
== NULL
);
686 edge_to_cases
= htab_create (37,
689 edge_to_cases_cleanup
);
692 /* Return nonzero if we are recording information for case labels. */
695 recording_case_labels_p (void)
697 return (edge_to_cases
!= NULL
);
700 /* Stop recording information mapping edges to case labels and
701 remove any information we have recorded. */
703 end_recording_case_labels (void)
705 htab_delete (edge_to_cases
);
706 edge_to_cases
= NULL
;
709 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
712 record_switch_edge (edge e
, tree case_label
)
714 struct edge_to_cases_elt
*elt
;
717 /* Build a hash table element so we can see if E is already
719 elt
= XNEW (struct edge_to_cases_elt
);
721 elt
->case_labels
= case_label
;
723 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
727 /* E was not in the hash table. Install E into the hash table. */
732 /* E was already in the hash table. Free ELT as we do not need it
736 /* Get the entry stored in the hash table. */
737 elt
= (struct edge_to_cases_elt
*) *slot
;
739 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
740 TREE_CHAIN (case_label
) = elt
->case_labels
;
741 elt
->case_labels
= case_label
;
745 /* If we are inside a {start,end}_recording_cases block, then return
746 a chain of CASE_LABEL_EXPRs from T which reference E.
748 Otherwise return NULL. */
751 get_cases_for_edge (edge e
, tree t
)
753 struct edge_to_cases_elt elt
, *elt_p
;
758 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
759 chains available. Return NULL so the caller can detect this case. */
760 if (!recording_case_labels_p ())
765 elt
.case_labels
= NULL
;
766 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
770 elt_p
= (struct edge_to_cases_elt
*)*slot
;
771 return elt_p
->case_labels
;
774 /* If we did not find E in the hash table, then this must be the first
775 time we have been queried for information about E & T. Add all the
776 elements from T to the hash table then perform the query again. */
778 vec
= SWITCH_LABELS (t
);
779 n
= TREE_VEC_LENGTH (vec
);
780 for (i
= 0; i
< n
; i
++)
782 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
783 basic_block label_bb
= label_to_block (lab
);
784 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
789 /* Create the edges for a SWITCH_EXPR starting at block BB.
790 At this point, the switch body has been lowered and the
791 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
794 make_switch_expr_edges (basic_block bb
)
796 tree entry
= last_stmt (bb
);
800 vec
= SWITCH_LABELS (entry
);
801 n
= TREE_VEC_LENGTH (vec
);
803 for (i
= 0; i
< n
; ++i
)
805 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
806 basic_block label_bb
= label_to_block (lab
);
807 make_edge (bb
, label_bb
, 0);
812 /* Return the basic block holding label DEST. */
815 label_to_block_fn (struct function
*ifun
, tree dest
)
817 int uid
= LABEL_DECL_UID (dest
);
819 /* We would die hard when faced by an undefined label. Emit a label to
820 the very first basic block. This will hopefully make even the dataflow
821 and undefined variable warnings quite right. */
822 if ((errorcount
|| sorrycount
) && uid
< 0)
824 block_stmt_iterator bsi
=
825 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
828 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
829 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
830 uid
= LABEL_DECL_UID (dest
);
832 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
833 <= (unsigned int) uid
)
835 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
838 /* Create edges for a goto statement at block BB. */
841 make_goto_expr_edges (basic_block bb
)
844 basic_block target_bb
;
846 block_stmt_iterator last
= bsi_last (bb
);
848 goto_t
= bsi_stmt (last
);
850 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
851 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
852 from a nonlocal goto. */
853 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
857 tree dest
= GOTO_DESTINATION (goto_t
);
860 /* A GOTO to a local label creates normal edges. */
861 if (simple_goto_p (goto_t
))
863 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
864 #ifdef USE_MAPPED_LOCATION
865 e
->goto_locus
= EXPR_LOCATION (goto_t
);
867 e
->goto_locus
= EXPR_LOCUS (goto_t
);
869 bsi_remove (&last
, true);
873 /* Nothing more to do for nonlocal gotos. */
874 if (TREE_CODE (dest
) == LABEL_DECL
)
877 /* Computed gotos remain. */
880 /* Look for the block starting with the destination label. In the
881 case of a computed goto, make an edge to any label block we find
883 FOR_EACH_BB (target_bb
)
885 block_stmt_iterator bsi
;
887 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
889 tree target
= bsi_stmt (bsi
);
891 if (TREE_CODE (target
) != LABEL_EXPR
)
895 /* Computed GOTOs. Make an edge to every label block that has
896 been marked as a potential target for a computed goto. */
897 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && !for_call
)
898 /* Nonlocal GOTO target. Make an edge to every label block
899 that has been marked as a potential target for a nonlocal
901 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
))
903 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
911 /*---------------------------------------------------------------------------
913 ---------------------------------------------------------------------------*/
915 /* Cleanup useless labels in basic blocks. This is something we wish
916 to do early because it allows us to group case labels before creating
917 the edges for the CFG, and it speeds up block statement iterators in
919 We only run this pass once, running it more than once is probably not
922 /* A map from basic block index to the leading label of that block. */
923 static tree
*label_for_bb
;
925 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
927 update_eh_label (struct eh_region
*region
)
929 tree old_label
= get_eh_region_tree_label (region
);
933 basic_block bb
= label_to_block (old_label
);
935 /* ??? After optimizing, there may be EH regions with labels
936 that have already been removed from the function body, so
937 there is no basic block for them. */
941 new_label
= label_for_bb
[bb
->index
];
942 set_eh_region_tree_label (region
, new_label
);
946 /* Given LABEL return the first label in the same basic block. */
948 main_block_label (tree label
)
950 basic_block bb
= label_to_block (label
);
952 /* label_to_block possibly inserted undefined label into the chain. */
953 if (!label_for_bb
[bb
->index
])
954 label_for_bb
[bb
->index
] = label
;
955 return label_for_bb
[bb
->index
];
958 /* Cleanup redundant labels. This is a three-step process:
959 1) Find the leading label for each block.
960 2) Redirect all references to labels to the leading labels.
961 3) Cleanup all useless labels. */
964 cleanup_dead_labels (void)
967 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
969 /* Find a suitable label for each block. We use the first user-defined
970 label if there is one, or otherwise just the first label we see. */
973 block_stmt_iterator i
;
975 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
977 tree label
, stmt
= bsi_stmt (i
);
979 if (TREE_CODE (stmt
) != LABEL_EXPR
)
982 label
= LABEL_EXPR_LABEL (stmt
);
984 /* If we have not yet seen a label for the current block,
985 remember this one and see if there are more labels. */
986 if (! label_for_bb
[bb
->index
])
988 label_for_bb
[bb
->index
] = label
;
992 /* If we did see a label for the current block already, but it
993 is an artificially created label, replace it if the current
994 label is a user defined label. */
995 if (! DECL_ARTIFICIAL (label
)
996 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
998 label_for_bb
[bb
->index
] = label
;
1004 /* Now redirect all jumps/branches to the selected label.
1005 First do so for each block ending in a control statement. */
1008 tree stmt
= last_stmt (bb
);
1012 switch (TREE_CODE (stmt
))
1016 tree true_branch
, false_branch
;
1018 true_branch
= COND_EXPR_THEN (stmt
);
1019 false_branch
= COND_EXPR_ELSE (stmt
);
1021 GOTO_DESTINATION (true_branch
)
1022 = main_block_label (GOTO_DESTINATION (true_branch
));
1023 GOTO_DESTINATION (false_branch
)
1024 = main_block_label (GOTO_DESTINATION (false_branch
));
1032 tree vec
= SWITCH_LABELS (stmt
);
1033 size_t n
= TREE_VEC_LENGTH (vec
);
1035 /* Replace all destination labels. */
1036 for (i
= 0; i
< n
; ++i
)
1038 tree elt
= TREE_VEC_ELT (vec
, i
);
1039 tree label
= main_block_label (CASE_LABEL (elt
));
1040 CASE_LABEL (elt
) = label
;
1045 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1046 remove them until after we've created the CFG edges. */
1048 if (! computed_goto_p (stmt
))
1050 GOTO_DESTINATION (stmt
)
1051 = main_block_label (GOTO_DESTINATION (stmt
));
1060 for_each_eh_region (update_eh_label
);
1062 /* Finally, purge dead labels. All user-defined labels and labels that
1063 can be the target of non-local gotos and labels which have their
1064 address taken are preserved. */
1067 block_stmt_iterator i
;
1068 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1070 if (! label_for_this_bb
)
1073 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1075 tree label
, stmt
= bsi_stmt (i
);
1077 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1080 label
= LABEL_EXPR_LABEL (stmt
);
1082 if (label
== label_for_this_bb
1083 || ! DECL_ARTIFICIAL (label
)
1084 || DECL_NONLOCAL (label
)
1085 || FORCED_LABEL (label
))
1088 bsi_remove (&i
, true);
1092 free (label_for_bb
);
1095 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1096 and scan the sorted vector of cases. Combine the ones jumping to the
1098 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1101 group_case_labels (void)
1107 tree stmt
= last_stmt (bb
);
1108 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1110 tree labels
= SWITCH_LABELS (stmt
);
1111 int old_size
= TREE_VEC_LENGTH (labels
);
1112 int i
, j
, new_size
= old_size
;
1113 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1116 /* The default label is always the last case in a switch
1117 statement after gimplification. */
1118 default_label
= CASE_LABEL (default_case
);
1120 /* Look for possible opportunities to merge cases.
1121 Ignore the last element of the label vector because it
1122 must be the default case. */
1124 while (i
< old_size
- 1)
1126 tree base_case
, base_label
, base_high
;
1127 base_case
= TREE_VEC_ELT (labels
, i
);
1129 gcc_assert (base_case
);
1130 base_label
= CASE_LABEL (base_case
);
1132 /* Discard cases that have the same destination as the
1134 if (base_label
== default_label
)
1136 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1142 base_high
= CASE_HIGH (base_case
) ?
1143 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1145 /* Try to merge case labels. Break out when we reach the end
1146 of the label vector or when we cannot merge the next case
1147 label with the current one. */
1148 while (i
< old_size
- 1)
1150 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1151 tree merge_label
= CASE_LABEL (merge_case
);
1152 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1153 integer_one_node
, 1);
1155 /* Merge the cases if they jump to the same place,
1156 and their ranges are consecutive. */
1157 if (merge_label
== base_label
1158 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1160 base_high
= CASE_HIGH (merge_case
) ?
1161 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1162 CASE_HIGH (base_case
) = base_high
;
1163 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1172 /* Compress the case labels in the label vector, and adjust the
1173 length of the vector. */
1174 for (i
= 0, j
= 0; i
< new_size
; i
++)
1176 while (! TREE_VEC_ELT (labels
, j
))
1178 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1180 TREE_VEC_LENGTH (labels
) = new_size
;
1185 /* Checks whether we can merge block B into block A. */
1188 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1191 block_stmt_iterator bsi
;
1194 if (!single_succ_p (a
))
1197 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1200 if (single_succ (a
) != b
)
1203 if (!single_pred_p (b
))
1206 if (b
== EXIT_BLOCK_PTR
)
1209 /* If A ends by a statement causing exceptions or something similar, we
1210 cannot merge the blocks. */
1211 stmt
= last_stmt (a
);
1212 if (stmt
&& stmt_ends_bb_p (stmt
))
1215 /* Do not allow a block with only a non-local label to be merged. */
1216 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1217 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1220 /* It must be possible to eliminate all phi nodes in B. If ssa form
1221 is not up-to-date, we cannot eliminate any phis. */
1222 phi
= phi_nodes (b
);
1225 if (need_ssa_update_p ())
1228 for (; phi
; phi
= PHI_CHAIN (phi
))
1229 if (!is_gimple_reg (PHI_RESULT (phi
))
1230 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1234 /* Do not remove user labels. */
1235 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1237 stmt
= bsi_stmt (bsi
);
1238 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1240 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1244 /* Protect the loop latches. */
1246 && b
->loop_father
->latch
== b
)
1252 /* Replaces all uses of NAME by VAL. */
1255 replace_uses_by (tree name
, tree val
)
1257 imm_use_iterator imm_iter
;
1262 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1264 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1266 stmt
= USE_STMT (use
);
1267 replace_exp (use
, val
);
1269 if (TREE_CODE (stmt
) == PHI_NODE
)
1271 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1272 if (e
->flags
& EDGE_ABNORMAL
)
1274 /* This can only occur for virtual operands, since
1275 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1276 would prevent replacement. */
1277 gcc_assert (!is_gimple_reg (name
));
1278 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1282 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1285 /* We do not update the statements in the loop above. Consider
1288 If we performed the update in the first loop, the statement
1289 would be rescanned after first occurrence of w is replaced,
1290 the new uses would be placed to the beginning of the list,
1291 and we would never process them. */
1292 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1296 fold_stmt_inplace (stmt
);
1298 rhs
= get_rhs (stmt
);
1299 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1300 recompute_tree_invariant_for_addr_expr (rhs
);
1302 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1303 mark_new_vars_to_rename (stmt
);
1306 VEC_free (tree
, heap
, stmts
);
1308 /* Also update the trees stored in loop structures. */
1313 for (i
= 0; i
< current_loops
->num
; i
++)
1315 loop
= current_loops
->parray
[i
];
1317 substitute_in_loop_info (loop
, name
, val
);
1322 /* Merge block B into block A. */
1325 tree_merge_blocks (basic_block a
, basic_block b
)
1327 block_stmt_iterator bsi
;
1328 tree_stmt_iterator last
;
1332 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1334 /* Remove all single-valued PHI nodes from block B of the form
1335 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1337 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1339 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1341 bool may_replace_uses
= may_propagate_copy (def
, use
);
1343 /* In case we have loops to care about, do not propagate arguments of
1344 loop closed ssa phi nodes. */
1346 && is_gimple_reg (def
)
1347 && TREE_CODE (use
) == SSA_NAME
1348 && a
->loop_father
!= b
->loop_father
)
1349 may_replace_uses
= false;
1351 if (!may_replace_uses
)
1353 gcc_assert (is_gimple_reg (def
));
1355 /* Note that just emitting the copies is fine -- there is no problem
1356 with ordering of phi nodes. This is because A is the single
1357 predecessor of B, therefore results of the phi nodes cannot
1358 appear as arguments of the phi nodes. */
1359 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1360 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1361 SET_PHI_RESULT (phi
, NULL_TREE
);
1362 SSA_NAME_DEF_STMT (def
) = copy
;
1365 replace_uses_by (def
, use
);
1367 remove_phi_node (phi
, NULL
);
1370 /* Ensure that B follows A. */
1371 move_block_after (b
, a
);
1373 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1374 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1376 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1377 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1379 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1381 tree label
= bsi_stmt (bsi
);
1383 bsi_remove (&bsi
, false);
1384 /* Now that we can thread computed gotos, we might have
1385 a situation where we have a forced label in block B
1386 However, the label at the start of block B might still be
1387 used in other ways (think about the runtime checking for
1388 Fortran assigned gotos). So we can not just delete the
1389 label. Instead we move the label to the start of block A. */
1390 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1392 block_stmt_iterator dest_bsi
= bsi_start (a
);
1393 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1398 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1403 /* Merge the chains. */
1404 last
= tsi_last (a
->stmt_list
);
1405 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1406 b
->stmt_list
= NULL
;
1410 /* Return the one of two successors of BB that is not reachable by a
1411 reached by a complex edge, if there is one. Else, return BB. We use
1412 this in optimizations that use post-dominators for their heuristics,
1413 to catch the cases in C++ where function calls are involved. */
1416 single_noncomplex_succ (basic_block bb
)
1419 if (EDGE_COUNT (bb
->succs
) != 2)
1422 e0
= EDGE_SUCC (bb
, 0);
1423 e1
= EDGE_SUCC (bb
, 1);
1424 if (e0
->flags
& EDGE_COMPLEX
)
1426 if (e1
->flags
& EDGE_COMPLEX
)
1434 /* Walk the function tree removing unnecessary statements.
1436 * Empty statement nodes are removed
1438 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1440 * Unnecessary COND_EXPRs are removed
1442 * Some unnecessary BIND_EXPRs are removed
1444 Clearly more work could be done. The trick is doing the analysis
1445 and removal fast enough to be a net improvement in compile times.
1447 Note that when we remove a control structure such as a COND_EXPR
1448 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1449 to ensure we eliminate all the useless code. */
1460 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1463 remove_useless_stmts_warn_notreached (tree stmt
)
1465 if (EXPR_HAS_LOCATION (stmt
))
1467 location_t loc
= EXPR_LOCATION (stmt
);
1468 if (LOCATION_LINE (loc
) > 0)
1470 warning (0, "%Hwill never be executed", &loc
);
1475 switch (TREE_CODE (stmt
))
1477 case STATEMENT_LIST
:
1479 tree_stmt_iterator i
;
1480 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1481 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1487 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1489 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1491 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1495 case TRY_FINALLY_EXPR
:
1496 case TRY_CATCH_EXPR
:
1497 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1499 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1504 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1505 case EH_FILTER_EXPR
:
1506 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1508 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1511 /* Not a live container. */
1519 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1521 tree then_clause
, else_clause
, cond
;
1522 bool save_has_label
, then_has_label
, else_has_label
;
1524 save_has_label
= data
->has_label
;
1525 data
->has_label
= false;
1526 data
->last_goto
= NULL
;
1528 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1530 then_has_label
= data
->has_label
;
1531 data
->has_label
= false;
1532 data
->last_goto
= NULL
;
1534 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1536 else_has_label
= data
->has_label
;
1537 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1539 then_clause
= COND_EXPR_THEN (*stmt_p
);
1540 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1541 cond
= fold (COND_EXPR_COND (*stmt_p
));
1543 /* If neither arm does anything at all, we can remove the whole IF. */
1544 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1546 *stmt_p
= build_empty_stmt ();
1547 data
->repeat
= true;
1550 /* If there are no reachable statements in an arm, then we can
1551 zap the entire conditional. */
1552 else if (integer_nonzerop (cond
) && !else_has_label
)
1554 if (warn_notreached
)
1555 remove_useless_stmts_warn_notreached (else_clause
);
1556 *stmt_p
= then_clause
;
1557 data
->repeat
= true;
1559 else if (integer_zerop (cond
) && !then_has_label
)
1561 if (warn_notreached
)
1562 remove_useless_stmts_warn_notreached (then_clause
);
1563 *stmt_p
= else_clause
;
1564 data
->repeat
= true;
1567 /* Check a couple of simple things on then/else with single stmts. */
1570 tree then_stmt
= expr_only (then_clause
);
1571 tree else_stmt
= expr_only (else_clause
);
1573 /* Notice branches to a common destination. */
1574 if (then_stmt
&& else_stmt
1575 && TREE_CODE (then_stmt
) == GOTO_EXPR
1576 && TREE_CODE (else_stmt
) == GOTO_EXPR
1577 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1579 *stmt_p
= then_stmt
;
1580 data
->repeat
= true;
1583 /* If the THEN/ELSE clause merely assigns a value to a variable or
1584 parameter which is already known to contain that value, then
1585 remove the useless THEN/ELSE clause. */
1586 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1589 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1590 && TREE_OPERAND (else_stmt
, 0) == cond
1591 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1592 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1594 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1595 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1596 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1597 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1599 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1600 ? then_stmt
: else_stmt
);
1601 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1602 ? &COND_EXPR_THEN (*stmt_p
)
1603 : &COND_EXPR_ELSE (*stmt_p
));
1606 && TREE_CODE (stmt
) == MODIFY_EXPR
1607 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1608 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1609 *location
= alloc_stmt_list ();
1613 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1614 would be re-introduced during lowering. */
1615 data
->last_goto
= NULL
;
1620 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1622 bool save_may_branch
, save_may_throw
;
1623 bool this_may_branch
, this_may_throw
;
1625 /* Collect may_branch and may_throw information for the body only. */
1626 save_may_branch
= data
->may_branch
;
1627 save_may_throw
= data
->may_throw
;
1628 data
->may_branch
= false;
1629 data
->may_throw
= false;
1630 data
->last_goto
= NULL
;
1632 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1634 this_may_branch
= data
->may_branch
;
1635 this_may_throw
= data
->may_throw
;
1636 data
->may_branch
|= save_may_branch
;
1637 data
->may_throw
|= save_may_throw
;
1638 data
->last_goto
= NULL
;
1640 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1642 /* If the body is empty, then we can emit the FINALLY block without
1643 the enclosing TRY_FINALLY_EXPR. */
1644 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1646 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1647 data
->repeat
= true;
1650 /* If the handler is empty, then we can emit the TRY block without
1651 the enclosing TRY_FINALLY_EXPR. */
1652 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1654 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1655 data
->repeat
= true;
1658 /* If the body neither throws, nor branches, then we can safely
1659 string the TRY and FINALLY blocks together. */
1660 else if (!this_may_branch
&& !this_may_throw
)
1662 tree stmt
= *stmt_p
;
1663 *stmt_p
= TREE_OPERAND (stmt
, 0);
1664 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1665 data
->repeat
= true;
1671 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1673 bool save_may_throw
, this_may_throw
;
1674 tree_stmt_iterator i
;
1677 /* Collect may_throw information for the body only. */
1678 save_may_throw
= data
->may_throw
;
1679 data
->may_throw
= false;
1680 data
->last_goto
= NULL
;
1682 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1684 this_may_throw
= data
->may_throw
;
1685 data
->may_throw
= save_may_throw
;
1687 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1688 if (!this_may_throw
)
1690 if (warn_notreached
)
1691 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1692 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1693 data
->repeat
= true;
1697 /* Process the catch clause specially. We may be able to tell that
1698 no exceptions propagate past this point. */
1700 this_may_throw
= true;
1701 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1702 stmt
= tsi_stmt (i
);
1703 data
->last_goto
= NULL
;
1705 switch (TREE_CODE (stmt
))
1708 for (; !tsi_end_p (i
); tsi_next (&i
))
1710 stmt
= tsi_stmt (i
);
1711 /* If we catch all exceptions, then the body does not
1712 propagate exceptions past this point. */
1713 if (CATCH_TYPES (stmt
) == NULL
)
1714 this_may_throw
= false;
1715 data
->last_goto
= NULL
;
1716 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1720 case EH_FILTER_EXPR
:
1721 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1722 this_may_throw
= false;
1723 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1724 this_may_throw
= false;
1725 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1729 /* Otherwise this is a cleanup. */
1730 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1732 /* If the cleanup is empty, then we can emit the TRY block without
1733 the enclosing TRY_CATCH_EXPR. */
1734 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1736 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1737 data
->repeat
= true;
1741 data
->may_throw
|= this_may_throw
;
1746 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1750 /* First remove anything underneath the BIND_EXPR. */
1751 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1753 /* If the BIND_EXPR has no variables, then we can pull everything
1754 up one level and remove the BIND_EXPR, unless this is the toplevel
1755 BIND_EXPR for the current function or an inlined function.
1757 When this situation occurs we will want to apply this
1758 optimization again. */
1759 block
= BIND_EXPR_BLOCK (*stmt_p
);
1760 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1761 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1763 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1764 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1767 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1768 data
->repeat
= true;
1774 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1776 tree dest
= GOTO_DESTINATION (*stmt_p
);
1778 data
->may_branch
= true;
1779 data
->last_goto
= NULL
;
1781 /* Record the last goto expr, so that we can delete it if unnecessary. */
1782 if (TREE_CODE (dest
) == LABEL_DECL
)
1783 data
->last_goto
= stmt_p
;
1788 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1790 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1792 data
->has_label
= true;
1794 /* We do want to jump across non-local label receiver code. */
1795 if (DECL_NONLOCAL (label
))
1796 data
->last_goto
= NULL
;
1798 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1800 *data
->last_goto
= build_empty_stmt ();
1801 data
->repeat
= true;
1804 /* ??? Add something here to delete unused labels. */
1808 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1809 decl. This allows us to eliminate redundant or useless
1810 calls to "const" functions.
1812 Gimplifier already does the same operation, but we may notice functions
1813 being const and pure once their calls has been gimplified, so we need
1814 to update the flag. */
1817 update_call_expr_flags (tree call
)
1819 tree decl
= get_callee_fndecl (call
);
1822 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1823 TREE_SIDE_EFFECTS (call
) = 0;
1824 if (TREE_NOTHROW (decl
))
1825 TREE_NOTHROW (call
) = 1;
1829 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1832 notice_special_calls (tree t
)
1834 int flags
= call_expr_flags (t
);
1836 if (flags
& ECF_MAY_BE_ALLOCA
)
1837 current_function_calls_alloca
= true;
1838 if (flags
& ECF_RETURNS_TWICE
)
1839 current_function_calls_setjmp
= true;
1843 /* Clear flags set by notice_special_calls. Used by dead code removal
1844 to update the flags. */
1847 clear_special_calls (void)
1849 current_function_calls_alloca
= false;
1850 current_function_calls_setjmp
= false;
1855 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1859 switch (TREE_CODE (t
))
1862 remove_useless_stmts_cond (tp
, data
);
1865 case TRY_FINALLY_EXPR
:
1866 remove_useless_stmts_tf (tp
, data
);
1869 case TRY_CATCH_EXPR
:
1870 remove_useless_stmts_tc (tp
, data
);
1874 remove_useless_stmts_bind (tp
, data
);
1878 remove_useless_stmts_goto (tp
, data
);
1882 remove_useless_stmts_label (tp
, data
);
1887 data
->last_goto
= NULL
;
1888 data
->may_branch
= true;
1893 data
->last_goto
= NULL
;
1894 notice_special_calls (t
);
1895 update_call_expr_flags (t
);
1896 if (tree_could_throw_p (t
))
1897 data
->may_throw
= true;
1901 data
->last_goto
= NULL
;
1903 op
= get_call_expr_in (t
);
1906 update_call_expr_flags (op
);
1907 notice_special_calls (op
);
1909 if (tree_could_throw_p (t
))
1910 data
->may_throw
= true;
1913 case STATEMENT_LIST
:
1915 tree_stmt_iterator i
= tsi_start (t
);
1916 while (!tsi_end_p (i
))
1919 if (IS_EMPTY_STMT (t
))
1925 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1928 if (TREE_CODE (t
) == STATEMENT_LIST
)
1930 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1940 data
->last_goto
= NULL
;
1944 data
->last_goto
= NULL
;
1950 remove_useless_stmts (void)
1952 struct rus_data data
;
1954 clear_special_calls ();
1958 memset (&data
, 0, sizeof (data
));
1959 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1961 while (data
.repeat
);
1966 struct tree_opt_pass pass_remove_useless_stmts
=
1968 "useless", /* name */
1970 remove_useless_stmts
, /* execute */
1973 0, /* static_pass_number */
1975 PROP_gimple_any
, /* properties_required */
1976 0, /* properties_provided */
1977 0, /* properties_destroyed */
1978 0, /* todo_flags_start */
1979 TODO_dump_func
, /* todo_flags_finish */
1983 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1986 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1990 /* Since this block is no longer reachable, we can just delete all
1991 of its PHI nodes. */
1992 phi
= phi_nodes (bb
);
1995 tree next
= PHI_CHAIN (phi
);
1996 remove_phi_node (phi
, NULL_TREE
);
2000 /* Remove edges to BB's successors. */
2001 while (EDGE_COUNT (bb
->succs
) > 0)
2002 remove_edge (EDGE_SUCC (bb
, 0));
2006 /* Remove statements of basic block BB. */
2009 remove_bb (basic_block bb
)
2011 block_stmt_iterator i
;
2012 #ifdef USE_MAPPED_LOCATION
2013 source_location loc
= UNKNOWN_LOCATION
;
2015 source_locus loc
= 0;
2020 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2021 if (dump_flags
& TDF_DETAILS
)
2023 dump_bb (bb
, dump_file
, 0);
2024 fprintf (dump_file
, "\n");
2028 /* If we remove the header or the latch of a loop, mark the loop for
2029 removal by setting its header and latch to NULL. */
2032 struct loop
*loop
= bb
->loop_father
;
2034 if (loop
->latch
== bb
2035 || loop
->header
== bb
)
2038 loop
->header
= NULL
;
2040 /* Also clean up the information associated with the loop. Updating
2041 it would waste time. More importantly, it may refer to ssa
2042 names that were defined in other removed basic block -- these
2043 ssa names are now removed and invalid. */
2044 free_numbers_of_iterations_estimates_loop (loop
);
2048 /* Remove all the instructions in the block. */
2049 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2051 tree stmt
= bsi_stmt (i
);
2052 if (TREE_CODE (stmt
) == LABEL_EXPR
2053 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2054 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2057 block_stmt_iterator new_bsi
;
2059 /* A non-reachable non-local label may still be referenced.
2060 But it no longer needs to carry the extra semantics of
2062 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2064 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2065 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2068 new_bb
= bb
->prev_bb
;
2069 new_bsi
= bsi_start (new_bb
);
2070 bsi_remove (&i
, false);
2071 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2075 /* Release SSA definitions if we are in SSA. Note that we
2076 may be called when not in SSA. For example,
2077 final_cleanup calls this function via
2078 cleanup_tree_cfg. */
2080 release_defs (stmt
);
2082 bsi_remove (&i
, true);
2085 /* Don't warn for removed gotos. Gotos are often removed due to
2086 jump threading, thus resulting in bogus warnings. Not great,
2087 since this way we lose warnings for gotos in the original
2088 program that are indeed unreachable. */
2089 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2091 #ifdef USE_MAPPED_LOCATION
2092 if (EXPR_HAS_LOCATION (stmt
))
2093 loc
= EXPR_LOCATION (stmt
);
2096 t
= EXPR_LOCUS (stmt
);
2097 if (t
&& LOCATION_LINE (*t
) > 0)
2103 /* If requested, give a warning that the first statement in the
2104 block is unreachable. We walk statements backwards in the
2105 loop above, so the last statement we process is the first statement
2107 #ifdef USE_MAPPED_LOCATION
2108 if (loc
> BUILTINS_LOCATION
)
2109 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2112 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2115 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2119 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2120 predicate VAL, return the edge that will be taken out of the block.
2121 If VAL does not match a unique edge, NULL is returned. */
2124 find_taken_edge (basic_block bb
, tree val
)
2128 stmt
= last_stmt (bb
);
2131 gcc_assert (is_ctrl_stmt (stmt
));
2134 if (! is_gimple_min_invariant (val
))
2137 if (TREE_CODE (stmt
) == COND_EXPR
)
2138 return find_taken_edge_cond_expr (bb
, val
);
2140 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2141 return find_taken_edge_switch_expr (bb
, val
);
2143 if (computed_goto_p (stmt
))
2144 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2149 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2150 statement, determine which of the outgoing edges will be taken out of the
2151 block. Return NULL if either edge may be taken. */
2154 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2159 dest
= label_to_block (val
);
2162 e
= find_edge (bb
, dest
);
2163 gcc_assert (e
!= NULL
);
2169 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2170 statement, determine which of the two edges will be taken out of the
2171 block. Return NULL if either edge may be taken. */
2174 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2176 edge true_edge
, false_edge
;
2178 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2180 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2181 return (zero_p (val
) ? false_edge
: true_edge
);
2184 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2185 statement, determine which edge will be taken out of the block. Return
2186 NULL if any edge may be taken. */
2189 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2191 tree switch_expr
, taken_case
;
2192 basic_block dest_bb
;
2195 switch_expr
= last_stmt (bb
);
2196 taken_case
= find_case_label_for_value (switch_expr
, val
);
2197 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2199 e
= find_edge (bb
, dest_bb
);
2205 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2206 We can make optimal use here of the fact that the case labels are
2207 sorted: We can do a binary search for a case matching VAL. */
2210 find_case_label_for_value (tree switch_expr
, tree val
)
2212 tree vec
= SWITCH_LABELS (switch_expr
);
2213 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2214 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2216 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2218 size_t i
= (high
+ low
) / 2;
2219 tree t
= TREE_VEC_ELT (vec
, i
);
2222 /* Cache the result of comparing CASE_LOW and val. */
2223 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2230 if (CASE_HIGH (t
) == NULL
)
2232 /* A singe-valued case label. */
2238 /* A case range. We can only handle integer ranges. */
2239 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2244 return default_case
;
2250 /*---------------------------------------------------------------------------
2252 ---------------------------------------------------------------------------*/
2254 /* Dump tree-specific information of block BB to file OUTF. */
2257 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2259 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2263 /* Dump a basic block on stderr. */
2266 debug_tree_bb (basic_block bb
)
2268 dump_bb (bb
, stderr
, 0);
2272 /* Dump basic block with index N on stderr. */
2275 debug_tree_bb_n (int n
)
2277 debug_tree_bb (BASIC_BLOCK (n
));
2278 return BASIC_BLOCK (n
);
2282 /* Dump the CFG on stderr.
2284 FLAGS are the same used by the tree dumping functions
2285 (see TDF_* in tree.h). */
2288 debug_tree_cfg (int flags
)
2290 dump_tree_cfg (stderr
, flags
);
2294 /* Dump the program showing basic block boundaries on the given FILE.
2296 FLAGS are the same used by the tree dumping functions (see TDF_* in
2300 dump_tree_cfg (FILE *file
, int flags
)
2302 if (flags
& TDF_DETAILS
)
2304 const char *funcname
2305 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2308 fprintf (file
, ";; Function %s\n\n", funcname
);
2309 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2310 n_basic_blocks
, n_edges
, last_basic_block
);
2312 brief_dump_cfg (file
);
2313 fprintf (file
, "\n");
2316 if (flags
& TDF_STATS
)
2317 dump_cfg_stats (file
);
2319 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2323 /* Dump CFG statistics on FILE. */
2326 dump_cfg_stats (FILE *file
)
2328 static long max_num_merged_labels
= 0;
2329 unsigned long size
, total
= 0;
2332 const char * const fmt_str
= "%-30s%-13s%12s\n";
2333 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2334 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2335 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2336 const char *funcname
2337 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2340 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2342 fprintf (file
, "---------------------------------------------------------\n");
2343 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2344 fprintf (file
, fmt_str
, "", " instances ", "used ");
2345 fprintf (file
, "---------------------------------------------------------\n");
2347 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2349 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2350 SCALE (size
), LABEL (size
));
2354 num_edges
+= EDGE_COUNT (bb
->succs
);
2355 size
= num_edges
* sizeof (struct edge_def
);
2357 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2359 fprintf (file
, "---------------------------------------------------------\n");
2360 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2362 fprintf (file
, "---------------------------------------------------------\n");
2363 fprintf (file
, "\n");
2365 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2366 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2368 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2369 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2371 fprintf (file
, "\n");
2375 /* Dump CFG statistics on stderr. Keep extern so that it's always
2376 linked in the final executable. */
2379 debug_cfg_stats (void)
2381 dump_cfg_stats (stderr
);
2385 /* Dump the flowgraph to a .vcg FILE. */
2388 tree_cfg2vcg (FILE *file
)
2393 const char *funcname
2394 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2396 /* Write the file header. */
2397 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2398 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2399 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2401 /* Write blocks and edges. */
2402 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2404 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2407 if (e
->flags
& EDGE_FAKE
)
2408 fprintf (file
, " linestyle: dotted priority: 10");
2410 fprintf (file
, " linestyle: solid priority: 100");
2412 fprintf (file
, " }\n");
2418 enum tree_code head_code
, end_code
;
2419 const char *head_name
, *end_name
;
2422 tree first
= first_stmt (bb
);
2423 tree last
= last_stmt (bb
);
2427 head_code
= TREE_CODE (first
);
2428 head_name
= tree_code_name
[head_code
];
2429 head_line
= get_lineno (first
);
2432 head_name
= "no-statement";
2436 end_code
= TREE_CODE (last
);
2437 end_name
= tree_code_name
[end_code
];
2438 end_line
= get_lineno (last
);
2441 end_name
= "no-statement";
2443 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2444 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2447 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2449 if (e
->dest
== EXIT_BLOCK_PTR
)
2450 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2452 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2454 if (e
->flags
& EDGE_FAKE
)
2455 fprintf (file
, " priority: 10 linestyle: dotted");
2457 fprintf (file
, " priority: 100 linestyle: solid");
2459 fprintf (file
, " }\n");
2462 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2466 fputs ("}\n\n", file
);
2471 /*---------------------------------------------------------------------------
2472 Miscellaneous helpers
2473 ---------------------------------------------------------------------------*/
2475 /* Return true if T represents a stmt that always transfers control. */
2478 is_ctrl_stmt (tree t
)
2480 return (TREE_CODE (t
) == COND_EXPR
2481 || TREE_CODE (t
) == SWITCH_EXPR
2482 || TREE_CODE (t
) == GOTO_EXPR
2483 || TREE_CODE (t
) == RETURN_EXPR
2484 || TREE_CODE (t
) == RESX_EXPR
);
2488 /* Return true if T is a statement that may alter the flow of control
2489 (e.g., a call to a non-returning function). */
2492 is_ctrl_altering_stmt (tree t
)
2497 call
= get_call_expr_in (t
);
2500 /* A non-pure/const CALL_EXPR alters flow control if the current
2501 function has nonlocal labels. */
2502 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2505 /* A CALL_EXPR also alters control flow if it does not return. */
2506 if (call_expr_flags (call
) & ECF_NORETURN
)
2510 /* OpenMP directives alter control flow. */
2511 if (OMP_DIRECTIVE_P (t
))
2514 /* If a statement can throw, it alters control flow. */
2515 return tree_can_throw_internal (t
);
2519 /* Return true if T is a computed goto. */
2522 computed_goto_p (tree t
)
2524 return (TREE_CODE (t
) == GOTO_EXPR
2525 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2529 /* Checks whether EXPR is a simple local goto. */
2532 simple_goto_p (tree expr
)
2534 return (TREE_CODE (expr
) == GOTO_EXPR
2535 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2539 /* Return true if T should start a new basic block. PREV_T is the
2540 statement preceding T. It is used when T is a label or a case label.
2541 Labels should only start a new basic block if their previous statement
2542 wasn't a label. Otherwise, sequence of labels would generate
2543 unnecessary basic blocks that only contain a single label. */
2546 stmt_starts_bb_p (tree t
, tree prev_t
)
2551 /* LABEL_EXPRs start a new basic block only if the preceding
2552 statement wasn't a label of the same type. This prevents the
2553 creation of consecutive blocks that have nothing but a single
2555 if (TREE_CODE (t
) == LABEL_EXPR
)
2557 /* Nonlocal and computed GOTO targets always start a new block. */
2558 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2559 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2562 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2564 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2567 cfg_stats
.num_merged_labels
++;
2578 /* Return true if T should end a basic block. */
2581 stmt_ends_bb_p (tree t
)
2583 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2587 /* Add gotos that used to be represented implicitly in the CFG. */
2590 disband_implicit_edges (void)
2593 block_stmt_iterator last
;
2600 last
= bsi_last (bb
);
2601 stmt
= last_stmt (bb
);
2603 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2605 /* Remove superfluous gotos from COND_EXPR branches. Moved
2606 from cfg_remove_useless_stmts here since it violates the
2607 invariants for tree--cfg correspondence and thus fits better
2608 here where we do it anyway. */
2609 e
= find_edge (bb
, bb
->next_bb
);
2612 if (e
->flags
& EDGE_TRUE_VALUE
)
2613 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2614 else if (e
->flags
& EDGE_FALSE_VALUE
)
2615 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2618 e
->flags
|= EDGE_FALLTHRU
;
2624 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2626 /* Remove the RETURN_EXPR if we may fall though to the exit
2628 gcc_assert (single_succ_p (bb
));
2629 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2631 if (bb
->next_bb
== EXIT_BLOCK_PTR
2632 && !TREE_OPERAND (stmt
, 0))
2634 bsi_remove (&last
, true);
2635 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2640 /* There can be no fallthru edge if the last statement is a control
2642 if (stmt
&& is_ctrl_stmt (stmt
))
2645 /* Find a fallthru edge and emit the goto if necessary. */
2646 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2647 if (e
->flags
& EDGE_FALLTHRU
)
2650 if (!e
|| e
->dest
== bb
->next_bb
)
2653 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2654 label
= tree_block_label (e
->dest
);
2656 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2657 #ifdef USE_MAPPED_LOCATION
2658 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2660 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2662 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2663 e
->flags
&= ~EDGE_FALLTHRU
;
2667 /* Remove block annotations and other datastructures. */
2670 delete_tree_cfg_annotations (void)
2672 label_to_block_map
= NULL
;
2676 /* Return the first statement in basic block BB. */
2679 first_stmt (basic_block bb
)
2681 block_stmt_iterator i
= bsi_start (bb
);
2682 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2686 /* Return the last statement in basic block BB. */
2689 last_stmt (basic_block bb
)
2691 block_stmt_iterator b
= bsi_last (bb
);
2692 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2696 /* Return a pointer to the last statement in block BB. */
2699 last_stmt_ptr (basic_block bb
)
2701 block_stmt_iterator last
= bsi_last (bb
);
2702 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2706 /* Return the last statement of an otherwise empty block. Return NULL
2707 if the block is totally empty, or if it contains more than one
2711 last_and_only_stmt (basic_block bb
)
2713 block_stmt_iterator i
= bsi_last (bb
);
2719 last
= bsi_stmt (i
);
2724 /* Empty statements should no longer appear in the instruction stream.
2725 Everything that might have appeared before should be deleted by
2726 remove_useless_stmts, and the optimizers should just bsi_remove
2727 instead of smashing with build_empty_stmt.
2729 Thus the only thing that should appear here in a block containing
2730 one executable statement is a label. */
2731 prev
= bsi_stmt (i
);
2732 if (TREE_CODE (prev
) == LABEL_EXPR
)
2739 /* Mark BB as the basic block holding statement T. */
2742 set_bb_for_stmt (tree t
, basic_block bb
)
2744 if (TREE_CODE (t
) == PHI_NODE
)
2746 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2748 tree_stmt_iterator i
;
2749 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2750 set_bb_for_stmt (tsi_stmt (i
), bb
);
2754 stmt_ann_t ann
= get_stmt_ann (t
);
2757 /* If the statement is a label, add the label to block-to-labels map
2758 so that we can speed up edge creation for GOTO_EXPRs. */
2759 if (TREE_CODE (t
) == LABEL_EXPR
)
2763 t
= LABEL_EXPR_LABEL (t
);
2764 uid
= LABEL_DECL_UID (t
);
2767 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2768 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2769 if (old_len
<= (unsigned) uid
)
2772 unsigned new_len
= 3 * uid
/ 2;
2774 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2776 addr
= VEC_address (basic_block
, label_to_block_map
);
2777 memset (&addr
[old_len
],
2778 0, sizeof (basic_block
) * (new_len
- old_len
));
2782 /* We're moving an existing label. Make sure that we've
2783 removed it from the old block. */
2785 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2786 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2791 /* Finds iterator for STMT. */
2793 extern block_stmt_iterator
2794 bsi_for_stmt (tree stmt
)
2796 block_stmt_iterator bsi
;
2798 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2799 if (bsi_stmt (bsi
) == stmt
)
2805 /* Mark statement T as modified, and update it. */
2807 update_modified_stmts (tree t
)
2809 if (TREE_CODE (t
) == STATEMENT_LIST
)
2811 tree_stmt_iterator i
;
2813 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2815 stmt
= tsi_stmt (i
);
2816 update_stmt_if_modified (stmt
);
2820 update_stmt_if_modified (t
);
2823 /* Insert statement (or statement list) T before the statement
2824 pointed-to by iterator I. M specifies how to update iterator I
2825 after insertion (see enum bsi_iterator_update). */
2828 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2830 set_bb_for_stmt (t
, i
->bb
);
2831 update_modified_stmts (t
);
2832 tsi_link_before (&i
->tsi
, t
, m
);
2836 /* Insert statement (or statement list) T after the statement
2837 pointed-to by iterator I. M specifies how to update iterator I
2838 after insertion (see enum bsi_iterator_update). */
2841 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2843 set_bb_for_stmt (t
, i
->bb
);
2844 update_modified_stmts (t
);
2845 tsi_link_after (&i
->tsi
, t
, m
);
2849 /* Remove the statement pointed to by iterator I. The iterator is updated
2850 to the next statement.
2852 When REMOVE_EH_INFO is true we remove the statement pointed to by
2853 iterator I from the EH tables. Otherwise we do not modify the EH
2856 Generally, REMOVE_EH_INFO should be true when the statement is going to
2857 be removed from the IL and not reinserted elsewhere. */
2860 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2862 tree t
= bsi_stmt (*i
);
2863 set_bb_for_stmt (t
, NULL
);
2864 delink_stmt_imm_use (t
);
2865 tsi_delink (&i
->tsi
);
2866 mark_stmt_modified (t
);
2868 remove_stmt_from_eh_region (t
);
2872 /* Move the statement at FROM so it comes right after the statement at TO. */
2875 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2877 tree stmt
= bsi_stmt (*from
);
2878 bsi_remove (from
, false);
2879 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2883 /* Move the statement at FROM so it comes right before the statement at TO. */
2886 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2888 tree stmt
= bsi_stmt (*from
);
2889 bsi_remove (from
, false);
2890 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2894 /* Move the statement at FROM to the end of basic block BB. */
2897 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2899 block_stmt_iterator last
= bsi_last (bb
);
2901 /* Have to check bsi_end_p because it could be an empty block. */
2902 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2903 bsi_move_before (from
, &last
);
2905 bsi_move_after (from
, &last
);
2909 /* Replace the contents of the statement pointed to by iterator BSI
2910 with STMT. If UPDATE_EH_INFO is true, the exception handling
2911 information of the original statement is moved to the new statement. */
2915 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2918 tree orig_stmt
= bsi_stmt (*bsi
);
2920 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2921 set_bb_for_stmt (stmt
, bsi
->bb
);
2923 /* Preserve EH region information from the original statement, if
2924 requested by the caller. */
2927 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2930 remove_stmt_from_eh_region (orig_stmt
);
2931 add_stmt_to_eh_region (stmt
, eh_region
);
2935 delink_stmt_imm_use (orig_stmt
);
2936 *bsi_stmt_ptr (*bsi
) = stmt
;
2937 mark_stmt_modified (stmt
);
2938 update_modified_stmts (stmt
);
2942 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2943 is made to place the statement in an existing basic block, but
2944 sometimes that isn't possible. When it isn't possible, the edge is
2945 split and the statement is added to the new block.
2947 In all cases, the returned *BSI points to the correct location. The
2948 return value is true if insertion should be done after the location,
2949 or false if it should be done before the location. If new basic block
2950 has to be created, it is stored in *NEW_BB. */
2953 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2954 basic_block
*new_bb
)
2956 basic_block dest
, src
;
2962 /* If the destination has one predecessor which has no PHI nodes,
2963 insert there. Except for the exit block.
2965 The requirement for no PHI nodes could be relaxed. Basically we
2966 would have to examine the PHIs to prove that none of them used
2967 the value set by the statement we want to insert on E. That
2968 hardly seems worth the effort. */
2969 if (single_pred_p (dest
)
2970 && ! phi_nodes (dest
)
2971 && dest
!= EXIT_BLOCK_PTR
)
2973 *bsi
= bsi_start (dest
);
2974 if (bsi_end_p (*bsi
))
2977 /* Make sure we insert after any leading labels. */
2978 tmp
= bsi_stmt (*bsi
);
2979 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2982 if (bsi_end_p (*bsi
))
2984 tmp
= bsi_stmt (*bsi
);
2987 if (bsi_end_p (*bsi
))
2989 *bsi
= bsi_last (dest
);
2996 /* If the source has one successor, the edge is not abnormal and
2997 the last statement does not end a basic block, insert there.
2998 Except for the entry block. */
3000 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3001 && single_succ_p (src
)
3002 && src
!= ENTRY_BLOCK_PTR
)
3004 *bsi
= bsi_last (src
);
3005 if (bsi_end_p (*bsi
))
3008 tmp
= bsi_stmt (*bsi
);
3009 if (!stmt_ends_bb_p (tmp
))
3012 /* Insert code just before returning the value. We may need to decompose
3013 the return in the case it contains non-trivial operand. */
3014 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3016 tree op
= TREE_OPERAND (tmp
, 0);
3017 if (op
&& !is_gimple_val (op
))
3019 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3020 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3021 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3028 /* Otherwise, create a new basic block, and split this edge. */
3029 dest
= split_edge (e
);
3032 e
= single_pred_edge (dest
);
3037 /* This routine will commit all pending edge insertions, creating any new
3038 basic blocks which are necessary. */
3041 bsi_commit_edge_inserts (void)
3047 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3050 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3051 bsi_commit_one_edge_insert (e
, NULL
);
3055 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3056 to this block, otherwise set it to NULL. */
3059 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3063 if (PENDING_STMT (e
))
3065 block_stmt_iterator bsi
;
3066 tree stmt
= PENDING_STMT (e
);
3068 PENDING_STMT (e
) = NULL_TREE
;
3070 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3071 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3073 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3078 /* Add STMT to the pending list of edge E. No actual insertion is
3079 made until a call to bsi_commit_edge_inserts () is made. */
3082 bsi_insert_on_edge (edge e
, tree stmt
)
3084 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3087 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3088 block has to be created, it is returned. */
3091 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3093 block_stmt_iterator bsi
;
3094 basic_block new_bb
= NULL
;
3096 gcc_assert (!PENDING_STMT (e
));
3098 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3099 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3101 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3106 /*---------------------------------------------------------------------------
3107 Tree specific functions for CFG manipulation
3108 ---------------------------------------------------------------------------*/
3110 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3113 reinstall_phi_args (edge new_edge
, edge old_edge
)
3117 if (!PENDING_STMT (old_edge
))
3120 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3122 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3124 tree result
= TREE_PURPOSE (var
);
3125 tree arg
= TREE_VALUE (var
);
3127 gcc_assert (result
== PHI_RESULT (phi
));
3129 add_phi_arg (phi
, arg
, new_edge
);
3132 PENDING_STMT (old_edge
) = NULL
;
3135 /* Returns the basic block after that the new basic block created
3136 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3137 near its "logical" location. This is of most help to humans looking
3138 at debugging dumps. */
3141 split_edge_bb_loc (edge edge_in
)
3143 basic_block dest
= edge_in
->dest
;
3145 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3146 return edge_in
->src
;
3148 return dest
->prev_bb
;
3151 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3152 Abort on abnormal edges. */
3155 tree_split_edge (edge edge_in
)
3157 basic_block new_bb
, after_bb
, dest
, src
;
3160 /* Abnormal edges cannot be split. */
3161 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3164 dest
= edge_in
->dest
;
3166 after_bb
= split_edge_bb_loc (edge_in
);
3168 new_bb
= create_empty_bb (after_bb
);
3169 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3170 new_bb
->count
= edge_in
->count
;
3171 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3172 new_edge
->probability
= REG_BR_PROB_BASE
;
3173 new_edge
->count
= edge_in
->count
;
3175 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3177 reinstall_phi_args (new_edge
, e
);
3183 /* Return true when BB has label LABEL in it. */
3186 has_label_p (basic_block bb
, tree label
)
3188 block_stmt_iterator bsi
;
3190 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3192 tree stmt
= bsi_stmt (bsi
);
3194 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3196 if (LABEL_EXPR_LABEL (stmt
) == label
)
3203 /* Callback for walk_tree, check that all elements with address taken are
3204 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3205 inside a PHI node. */
3208 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3211 bool in_phi
= (data
!= NULL
);
3216 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3217 #define CHECK_OP(N, MSG) \
3218 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3219 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3221 switch (TREE_CODE (t
))
3224 if (SSA_NAME_IN_FREE_LIST (t
))
3226 error ("SSA name in freelist but still referenced");
3232 x
= fold (ASSERT_EXPR_COND (t
));
3233 if (x
== boolean_false_node
)
3235 error ("ASSERT_EXPR with an always-false condition");
3241 x
= TREE_OPERAND (t
, 0);
3242 if (TREE_CODE (x
) == BIT_FIELD_REF
3243 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3245 error ("GIMPLE register modified with BIT_FIELD_REF");
3254 bool old_side_effects
;
3257 bool new_side_effects
;
3259 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3260 dead PHIs that take the address of something. But if the PHI
3261 result is dead, the fact that it takes the address of anything
3262 is irrelevant. Because we can not tell from here if a PHI result
3263 is dead, we just skip this check for PHIs altogether. This means
3264 we may be missing "valid" checks, but what can you do?
3265 This was PR19217. */
3269 old_invariant
= TREE_INVARIANT (t
);
3270 old_constant
= TREE_CONSTANT (t
);
3271 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3273 recompute_tree_invariant_for_addr_expr (t
);
3274 new_invariant
= TREE_INVARIANT (t
);
3275 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3276 new_constant
= TREE_CONSTANT (t
);
3278 if (old_invariant
!= new_invariant
)
3280 error ("invariant not recomputed when ADDR_EXPR changed");
3284 if (old_constant
!= new_constant
)
3286 error ("constant not recomputed when ADDR_EXPR changed");
3289 if (old_side_effects
!= new_side_effects
)
3291 error ("side effects not recomputed when ADDR_EXPR changed");
3295 /* Skip any references (they will be checked when we recurse down the
3296 tree) and ensure that any variable used as a prefix is marked
3298 for (x
= TREE_OPERAND (t
, 0);
3299 handled_component_p (x
);
3300 x
= TREE_OPERAND (x
, 0))
3303 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3305 if (!TREE_ADDRESSABLE (x
))
3307 error ("address taken, but ADDRESSABLE bit not set");
3314 x
= COND_EXPR_COND (t
);
3315 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3317 error ("non-boolean used in condition");
3320 if (!is_gimple_condexpr (x
))
3322 error ("invalid conditional operand");
3329 case FIX_TRUNC_EXPR
:
3331 case FIX_FLOOR_EXPR
:
3332 case FIX_ROUND_EXPR
:
3337 case NON_LVALUE_EXPR
:
3338 case TRUTH_NOT_EXPR
:
3339 CHECK_OP (0, "invalid operand to unary operator");
3346 case ARRAY_RANGE_REF
:
3348 case VIEW_CONVERT_EXPR
:
3349 /* We have a nest of references. Verify that each of the operands
3350 that determine where to reference is either a constant or a variable,
3351 verify that the base is valid, and then show we've already checked
3353 while (handled_component_p (t
))
3355 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3356 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3357 else if (TREE_CODE (t
) == ARRAY_REF
3358 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3360 CHECK_OP (1, "invalid array index");
3361 if (TREE_OPERAND (t
, 2))
3362 CHECK_OP (2, "invalid array lower bound");
3363 if (TREE_OPERAND (t
, 3))
3364 CHECK_OP (3, "invalid array stride");
3366 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3368 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3369 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3372 t
= TREE_OPERAND (t
, 0);
3375 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3377 error ("invalid reference prefix");
3389 case UNORDERED_EXPR
:
3400 case TRUNC_DIV_EXPR
:
3402 case FLOOR_DIV_EXPR
:
3403 case ROUND_DIV_EXPR
:
3404 case TRUNC_MOD_EXPR
:
3406 case FLOOR_MOD_EXPR
:
3407 case ROUND_MOD_EXPR
:
3409 case EXACT_DIV_EXPR
:
3419 CHECK_OP (0, "invalid operand to binary operator");
3420 CHECK_OP (1, "invalid operand to binary operator");
3432 /* Verify STMT, return true if STMT is not in GIMPLE form.
3433 TODO: Implement type checking. */
3436 verify_stmt (tree stmt
, bool last_in_block
)
3440 if (OMP_DIRECTIVE_P (stmt
))
3442 /* OpenMP directives are validated by the FE and never operated
3443 on by the optimizers. Furthermore, OMP_FOR may contain
3444 non-gimple expressions when the main index variable has had
3445 its address taken. This does not affect the loop itself
3446 because the header of an OMP_FOR is merely used to determine
3447 how to setup the parallel iteration. */
3451 if (!is_gimple_stmt (stmt
))
3453 error ("is not a valid GIMPLE statement");
3457 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3460 debug_generic_stmt (addr
);
3464 /* If the statement is marked as part of an EH region, then it is
3465 expected that the statement could throw. Verify that when we
3466 have optimizations that simplify statements such that we prove
3467 that they cannot throw, that we update other data structures
3469 if (lookup_stmt_eh_region (stmt
) >= 0)
3471 if (!tree_could_throw_p (stmt
))
3473 error ("statement marked for throw, but doesn%'t");
3476 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3478 error ("statement marked for throw in middle of block");
3486 debug_generic_stmt (stmt
);
3491 /* Return true when the T can be shared. */
3494 tree_node_can_be_shared (tree t
)
3496 if (IS_TYPE_OR_DECL_P (t
)
3497 || is_gimple_min_invariant (t
)
3498 || TREE_CODE (t
) == SSA_NAME
3499 || t
== error_mark_node
3500 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3503 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3506 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3507 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3508 || TREE_CODE (t
) == COMPONENT_REF
3509 || TREE_CODE (t
) == REALPART_EXPR
3510 || TREE_CODE (t
) == IMAGPART_EXPR
)
3511 t
= TREE_OPERAND (t
, 0);
3520 /* Called via walk_trees. Verify tree sharing. */
3523 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3525 htab_t htab
= (htab_t
) data
;
3528 if (tree_node_can_be_shared (*tp
))
3530 *walk_subtrees
= false;
3534 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3536 return (tree
) *slot
;
3543 /* Verify the GIMPLE statement chain. */
3549 block_stmt_iterator bsi
;
3554 timevar_push (TV_TREE_STMT_VERIFY
);
3555 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3562 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3564 int phi_num_args
= PHI_NUM_ARGS (phi
);
3566 if (bb_for_stmt (phi
) != bb
)
3568 error ("bb_for_stmt (phi) is set to a wrong basic block");
3572 for (i
= 0; i
< phi_num_args
; i
++)
3574 tree t
= PHI_ARG_DEF (phi
, i
);
3577 /* Addressable variables do have SSA_NAMEs but they
3578 are not considered gimple values. */
3579 if (TREE_CODE (t
) != SSA_NAME
3580 && TREE_CODE (t
) != FUNCTION_DECL
3581 && !is_gimple_val (t
))
3583 error ("PHI def is not a GIMPLE value");
3584 debug_generic_stmt (phi
);
3585 debug_generic_stmt (t
);
3589 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3592 debug_generic_stmt (addr
);
3596 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3599 error ("incorrect sharing of tree nodes");
3600 debug_generic_stmt (phi
);
3601 debug_generic_stmt (addr
);
3607 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3609 tree stmt
= bsi_stmt (bsi
);
3611 if (bb_for_stmt (stmt
) != bb
)
3613 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3618 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3619 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3622 error ("incorrect sharing of tree nodes");
3623 debug_generic_stmt (stmt
);
3624 debug_generic_stmt (addr
);
3631 internal_error ("verify_stmts failed");
3634 timevar_pop (TV_TREE_STMT_VERIFY
);
3638 /* Verifies that the flow information is OK. */
3641 tree_verify_flow_info (void)
3645 block_stmt_iterator bsi
;
3650 if (ENTRY_BLOCK_PTR
->stmt_list
)
3652 error ("ENTRY_BLOCK has a statement list associated with it");
3656 if (EXIT_BLOCK_PTR
->stmt_list
)
3658 error ("EXIT_BLOCK has a statement list associated with it");
3662 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3663 if (e
->flags
& EDGE_FALLTHRU
)
3665 error ("fallthru to exit from bb %d", e
->src
->index
);
3671 bool found_ctrl_stmt
= false;
3675 /* Skip labels on the start of basic block. */
3676 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3678 tree prev_stmt
= stmt
;
3680 stmt
= bsi_stmt (bsi
);
3682 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3685 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3687 error ("nonlocal label ");
3688 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3689 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3694 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3697 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3698 fprintf (stderr
, " to block does not match in bb %d",
3703 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3704 != current_function_decl
)
3707 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3708 fprintf (stderr
, " has incorrect context in bb %d",
3714 /* Verify that body of basic block BB is free of control flow. */
3715 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3717 tree stmt
= bsi_stmt (bsi
);
3719 if (found_ctrl_stmt
)
3721 error ("control flow in the middle of basic block %d",
3726 if (stmt_ends_bb_p (stmt
))
3727 found_ctrl_stmt
= true;
3729 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3732 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3733 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3738 bsi
= bsi_last (bb
);
3739 if (bsi_end_p (bsi
))
3742 stmt
= bsi_stmt (bsi
);
3744 err
|= verify_eh_edges (stmt
);
3746 if (is_ctrl_stmt (stmt
))
3748 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3749 if (e
->flags
& EDGE_FALLTHRU
)
3751 error ("fallthru edge after a control statement in bb %d",
3757 switch (TREE_CODE (stmt
))
3763 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3764 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3766 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3770 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3772 if (!true_edge
|| !false_edge
3773 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3774 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3775 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3776 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3777 || EDGE_COUNT (bb
->succs
) >= 3)
3779 error ("wrong outgoing edge flags at end of bb %d",
3784 if (!has_label_p (true_edge
->dest
,
3785 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3787 error ("%<then%> label does not match edge at end of bb %d",
3792 if (!has_label_p (false_edge
->dest
,
3793 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3795 error ("%<else%> label does not match edge at end of bb %d",
3803 if (simple_goto_p (stmt
))
3805 error ("explicit goto at end of bb %d", bb
->index
);
3810 /* FIXME. We should double check that the labels in the
3811 destination blocks have their address taken. */
3812 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3813 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3814 | EDGE_FALSE_VALUE
))
3815 || !(e
->flags
& EDGE_ABNORMAL
))
3817 error ("wrong outgoing edge flags at end of bb %d",
3825 if (!single_succ_p (bb
)
3826 || (single_succ_edge (bb
)->flags
3827 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3828 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3830 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3833 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3835 error ("return edge does not point to exit in bb %d",
3848 vec
= SWITCH_LABELS (stmt
);
3849 n
= TREE_VEC_LENGTH (vec
);
3851 /* Mark all the destination basic blocks. */
3852 for (i
= 0; i
< n
; ++i
)
3854 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3855 basic_block label_bb
= label_to_block (lab
);
3857 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3858 label_bb
->aux
= (void *)1;
3861 /* Verify that the case labels are sorted. */
3862 prev
= TREE_VEC_ELT (vec
, 0);
3863 for (i
= 1; i
< n
- 1; ++i
)
3865 tree c
= TREE_VEC_ELT (vec
, i
);
3868 error ("found default case not at end of case vector");
3872 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3874 error ("case labels not sorted: ");
3875 print_generic_expr (stderr
, prev
, 0);
3876 fprintf (stderr
," is greater than ");
3877 print_generic_expr (stderr
, c
, 0);
3878 fprintf (stderr
," but comes before it.\n");
3883 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3885 error ("no default case found at end of case vector");
3889 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3893 error ("extra outgoing edge %d->%d",
3894 bb
->index
, e
->dest
->index
);
3897 e
->dest
->aux
= (void *)2;
3898 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3899 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3901 error ("wrong outgoing edge flags at end of bb %d",
3907 /* Check that we have all of them. */
3908 for (i
= 0; i
< n
; ++i
)
3910 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3911 basic_block label_bb
= label_to_block (lab
);
3913 if (label_bb
->aux
!= (void *)2)
3915 error ("missing edge %i->%i",
3916 bb
->index
, label_bb
->index
);
3921 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3922 e
->dest
->aux
= (void *)0;
3929 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3930 verify_dominators (CDI_DOMINATORS
);
3936 /* Updates phi nodes after creating a forwarder block joined
3937 by edge FALLTHRU. */
3940 tree_make_forwarder_block (edge fallthru
)
3944 basic_block dummy
, bb
;
3945 tree phi
, new_phi
, var
;
3947 dummy
= fallthru
->src
;
3948 bb
= fallthru
->dest
;
3950 if (single_pred_p (bb
))
3953 /* If we redirected a branch we must create new phi nodes at the
3955 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3957 var
= PHI_RESULT (phi
);
3958 new_phi
= create_phi_node (var
, bb
);
3959 SSA_NAME_DEF_STMT (var
) = new_phi
;
3960 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3961 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3964 /* Ensure that the PHI node chain is in the same order. */
3965 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3967 /* Add the arguments we have stored on edges. */
3968 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3973 flush_pending_stmts (e
);
3978 /* Return a non-special label in the head of basic block BLOCK.
3979 Create one if it doesn't exist. */
3982 tree_block_label (basic_block bb
)
3984 block_stmt_iterator i
, s
= bsi_start (bb
);
3988 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3990 stmt
= bsi_stmt (i
);
3991 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3993 label
= LABEL_EXPR_LABEL (stmt
);
3994 if (!DECL_NONLOCAL (label
))
3997 bsi_move_before (&i
, &s
);
4002 label
= create_artificial_label ();
4003 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4004 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4009 /* Attempt to perform edge redirection by replacing a possibly complex
4010 jump instruction by a goto or by removing the jump completely.
4011 This can apply only if all edges now point to the same block. The
4012 parameters and return values are equivalent to
4013 redirect_edge_and_branch. */
4016 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4018 basic_block src
= e
->src
;
4019 block_stmt_iterator b
;
4022 /* We can replace or remove a complex jump only when we have exactly
4024 if (EDGE_COUNT (src
->succs
) != 2
4025 /* Verify that all targets will be TARGET. Specifically, the
4026 edge that is not E must also go to TARGET. */
4027 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4033 stmt
= bsi_stmt (b
);
4035 if (TREE_CODE (stmt
) == COND_EXPR
4036 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4038 bsi_remove (&b
, true);
4039 e
= ssa_redirect_edge (e
, target
);
4040 e
->flags
= EDGE_FALLTHRU
;
4048 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4049 edge representing the redirected branch. */
4052 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4054 basic_block bb
= e
->src
;
4055 block_stmt_iterator bsi
;
4059 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4062 if (e
->src
!= ENTRY_BLOCK_PTR
4063 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4066 if (e
->dest
== dest
)
4069 label
= tree_block_label (dest
);
4071 bsi
= bsi_last (bb
);
4072 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4074 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4077 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4078 ? COND_EXPR_THEN (stmt
)
4079 : COND_EXPR_ELSE (stmt
));
4080 GOTO_DESTINATION (stmt
) = label
;
4084 /* No non-abnormal edges should lead from a non-simple goto, and
4085 simple ones should be represented implicitly. */
4090 tree cases
= get_cases_for_edge (e
, stmt
);
4092 /* If we have a list of cases associated with E, then use it
4093 as it's a lot faster than walking the entire case vector. */
4096 edge e2
= find_edge (e
->src
, dest
);
4103 CASE_LABEL (cases
) = label
;
4104 cases
= TREE_CHAIN (cases
);
4107 /* If there was already an edge in the CFG, then we need
4108 to move all the cases associated with E to E2. */
4111 tree cases2
= get_cases_for_edge (e2
, stmt
);
4113 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4114 TREE_CHAIN (cases2
) = first
;
4119 tree vec
= SWITCH_LABELS (stmt
);
4120 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4122 for (i
= 0; i
< n
; i
++)
4124 tree elt
= TREE_VEC_ELT (vec
, i
);
4126 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4127 CASE_LABEL (elt
) = label
;
4135 bsi_remove (&bsi
, true);
4136 e
->flags
|= EDGE_FALLTHRU
;
4140 /* Otherwise it must be a fallthru edge, and we don't need to
4141 do anything besides redirecting it. */
4142 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4146 /* Update/insert PHI nodes as necessary. */
4148 /* Now update the edges in the CFG. */
4149 e
= ssa_redirect_edge (e
, dest
);
4155 /* Simple wrapper, as we can always redirect fallthru edges. */
4158 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4160 e
= tree_redirect_edge_and_branch (e
, dest
);
4167 /* Splits basic block BB after statement STMT (but at least after the
4168 labels). If STMT is NULL, BB is split just after the labels. */
4171 tree_split_block (basic_block bb
, void *stmt
)
4173 block_stmt_iterator bsi
, bsi_tgt
;
4179 new_bb
= create_empty_bb (bb
);
4181 /* Redirect the outgoing edges. */
4182 new_bb
->succs
= bb
->succs
;
4184 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4187 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4190 /* Move everything from BSI to the new basic block. */
4191 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4193 act
= bsi_stmt (bsi
);
4194 if (TREE_CODE (act
) == LABEL_EXPR
)
4207 bsi_tgt
= bsi_start (new_bb
);
4208 while (!bsi_end_p (bsi
))
4210 act
= bsi_stmt (bsi
);
4211 bsi_remove (&bsi
, false);
4212 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4219 /* Moves basic block BB after block AFTER. */
4222 tree_move_block_after (basic_block bb
, basic_block after
)
4224 if (bb
->prev_bb
== after
)
4228 link_block (bb
, after
);
4234 /* Return true if basic_block can be duplicated. */
4237 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4243 /* Create a duplicate of the basic block BB. NOTE: This does not
4244 preserve SSA form. */
4247 tree_duplicate_bb (basic_block bb
)
4250 block_stmt_iterator bsi
, bsi_tgt
;
4253 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4255 /* Copy the PHI nodes. We ignore PHI node arguments here because
4256 the incoming edges have not been setup yet. */
4257 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4259 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4260 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4263 /* Keep the chain of PHI nodes in the same order so that they can be
4264 updated by ssa_redirect_edge. */
4265 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4267 bsi_tgt
= bsi_start (new_bb
);
4268 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4270 def_operand_p def_p
;
4271 ssa_op_iter op_iter
;
4275 stmt
= bsi_stmt (bsi
);
4276 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4279 /* Create a new copy of STMT and duplicate STMT's virtual
4281 copy
= unshare_expr (stmt
);
4282 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4283 copy_virtual_operands (copy
, stmt
);
4284 region
= lookup_stmt_eh_region (stmt
);
4286 add_stmt_to_eh_region (copy
, region
);
4288 /* Create new names for all the definitions created by COPY and
4289 add replacement mappings for each new name. */
4290 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4291 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4298 /* Basic block BB_COPY was created by code duplication. Add phi node
4299 arguments for edges going out of BB_COPY. The blocks that were
4300 duplicated have BB_DUPLICATED set. */
4303 add_phi_args_after_copy_bb (basic_block bb_copy
)
4305 basic_block bb
, dest
;
4308 tree phi
, phi_copy
, phi_next
, def
;
4310 bb
= get_bb_original (bb_copy
);
4312 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4314 if (!phi_nodes (e_copy
->dest
))
4317 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4318 dest
= get_bb_original (e_copy
->dest
);
4320 dest
= e_copy
->dest
;
4322 e
= find_edge (bb
, dest
);
4325 /* During loop unrolling the target of the latch edge is copied.
4326 In this case we are not looking for edge to dest, but to
4327 duplicated block whose original was dest. */
4328 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4329 if ((e
->dest
->flags
& BB_DUPLICATED
)
4330 && get_bb_original (e
->dest
) == dest
)
4333 gcc_assert (e
!= NULL
);
4336 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4338 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4340 phi_next
= PHI_CHAIN (phi
);
4341 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4342 add_phi_arg (phi_copy
, def
, e_copy
);
4347 /* Blocks in REGION_COPY array of length N_REGION were created by
4348 duplication of basic blocks. Add phi node arguments for edges
4349 going from these blocks. */
4352 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4356 for (i
= 0; i
< n_region
; i
++)
4357 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4359 for (i
= 0; i
< n_region
; i
++)
4360 add_phi_args_after_copy_bb (region_copy
[i
]);
4362 for (i
= 0; i
< n_region
; i
++)
4363 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4366 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4367 important exit edge EXIT. By important we mean that no SSA name defined
4368 inside region is live over the other exit edges of the region. All entry
4369 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4370 to the duplicate of the region. SSA form, dominance and loop information
4371 is updated. The new basic blocks are stored to REGION_COPY in the same
4372 order as they had in REGION, provided that REGION_COPY is not NULL.
4373 The function returns false if it is unable to copy the region,
4377 tree_duplicate_sese_region (edge entry
, edge exit
,
4378 basic_block
*region
, unsigned n_region
,
4379 basic_block
*region_copy
)
4382 bool free_region_copy
= false, copying_header
= false;
4383 struct loop
*loop
= entry
->dest
->loop_father
;
4387 int total_freq
= 0, entry_freq
= 0;
4388 gcov_type total_count
= 0, entry_count
= 0;
4390 if (!can_copy_bbs_p (region
, n_region
))
4393 /* Some sanity checking. Note that we do not check for all possible
4394 missuses of the functions. I.e. if you ask to copy something weird,
4395 it will work, but the state of structures probably will not be
4397 for (i
= 0; i
< n_region
; i
++)
4399 /* We do not handle subloops, i.e. all the blocks must belong to the
4401 if (region
[i
]->loop_father
!= loop
)
4404 if (region
[i
] != entry
->dest
4405 && region
[i
] == loop
->header
)
4411 /* In case the function is used for loop header copying (which is the primary
4412 use), ensure that EXIT and its copy will be new latch and entry edges. */
4413 if (loop
->header
== entry
->dest
)
4415 copying_header
= true;
4416 loop
->copy
= loop
->outer
;
4418 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4421 for (i
= 0; i
< n_region
; i
++)
4422 if (region
[i
] != exit
->src
4423 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4429 region_copy
= XNEWVEC (basic_block
, n_region
);
4430 free_region_copy
= true;
4433 gcc_assert (!need_ssa_update_p ());
4435 /* Record blocks outside the region that are dominated by something
4437 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4438 initialize_original_copy_tables ();
4440 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4442 if (entry
->dest
->count
)
4444 total_count
= entry
->dest
->count
;
4445 entry_count
= entry
->count
;
4446 /* Fix up corner cases, to avoid division by zero or creation of negative
4448 if (entry_count
> total_count
)
4449 entry_count
= total_count
;
4453 total_freq
= entry
->dest
->frequency
;
4454 entry_freq
= EDGE_FREQUENCY (entry
);
4455 /* Fix up corner cases, to avoid division by zero or creation of negative
4457 if (total_freq
== 0)
4459 else if (entry_freq
> total_freq
)
4460 entry_freq
= total_freq
;
4463 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4464 split_edge_bb_loc (entry
));
4467 scale_bbs_frequencies_gcov_type (region
, n_region
,
4468 total_count
- entry_count
,
4470 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4475 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4477 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4482 loop
->header
= exit
->dest
;
4483 loop
->latch
= exit
->src
;
4486 /* Redirect the entry and add the phi node arguments. */
4487 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4488 gcc_assert (redirected
!= NULL
);
4489 flush_pending_stmts (entry
);
4491 /* Concerning updating of dominators: We must recount dominators
4492 for entry block and its copy. Anything that is outside of the
4493 region, but was dominated by something inside needs recounting as
4495 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4496 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4497 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4500 /* Add the other PHI node arguments. */
4501 add_phi_args_after_copy (region_copy
, n_region
);
4503 /* Update the SSA web. */
4504 update_ssa (TODO_update_ssa
);
4506 if (free_region_copy
)
4509 free_original_copy_tables ();
4514 DEF_VEC_P(basic_block);
4515 DEF_VEC_ALLOC_P(basic_block,heap);
4518 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4519 adding blocks when the dominator traversal reaches EXIT. This
4520 function silently assumes that ENTRY strictly dominates EXIT. */
4523 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4524 VEC(basic_block
,heap
) **bbs_p
)
4528 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4530 son
= next_dom_son (CDI_DOMINATORS
, son
))
4532 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4534 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4544 bitmap vars_to_remove
;
4545 htab_t new_label_map
;
4549 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4550 contained in *TP and change the DECL_CONTEXT of every local
4551 variable referenced in *TP. */
4554 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4556 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4559 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t
))))
4560 TREE_BLOCK (t
) = p
->block
;
4562 if (OMP_DIRECTIVE_P (t
)
4563 && TREE_CODE (t
) != OMP_RETURN
4564 && TREE_CODE (t
) != OMP_CONTINUE
)
4566 /* Do not remap variables inside OMP directives. Variables
4567 referenced in clauses and directive header belong to the
4568 parent function and should not be moved into the child
4570 bool save_remap_decls_p
= p
->remap_decls_p
;
4571 p
->remap_decls_p
= false;
4574 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4576 p
->remap_decls_p
= save_remap_decls_p
;
4578 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4580 if (TREE_CODE (t
) == LABEL_DECL
)
4582 if (p
->new_label_map
)
4584 struct tree_map in
, *out
;
4586 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4591 DECL_CONTEXT (t
) = p
->to_context
;
4593 else if (p
->remap_decls_p
)
4595 DECL_CONTEXT (t
) = p
->to_context
;
4597 if (TREE_CODE (t
) == VAR_DECL
)
4599 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4600 f
->unexpanded_var_list
4601 = tree_cons (0, t
, f
->unexpanded_var_list
);
4603 /* Mark T to be removed from the original function,
4604 otherwise it will be given a DECL_RTL when the
4605 original function is expanded. */
4606 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4610 else if (TYPE_P (t
))
4617 /* Move basic block BB from function CFUN to function DEST_FN. The
4618 block is moved out of the original linked list and placed after
4619 block AFTER in the new list. Also, the block is removed from the
4620 original array of blocks and placed in DEST_FN's array of blocks.
4621 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4622 updated to reflect the moved edges.
4624 On exit, local variables that need to be removed from
4625 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4628 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4629 basic_block after
, bool update_edge_count_p
,
4630 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4632 struct control_flow_graph
*cfg
;
4635 block_stmt_iterator si
;
4636 struct move_stmt_d d
;
4637 unsigned old_len
, new_len
;
4640 /* Link BB to the new linked list. */
4641 move_block_after (bb
, after
);
4643 /* Update the edge count in the corresponding flowgraphs. */
4644 if (update_edge_count_p
)
4645 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4647 cfun
->cfg
->x_n_edges
--;
4648 dest_cfun
->cfg
->x_n_edges
++;
4651 /* Remove BB from the original basic block array. */
4652 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4653 cfun
->cfg
->x_n_basic_blocks
--;
4655 /* Grow DEST_CFUN's basic block array if needed. */
4656 cfg
= dest_cfun
->cfg
;
4657 cfg
->x_n_basic_blocks
++;
4658 if (bb
->index
> cfg
->x_last_basic_block
)
4659 cfg
->x_last_basic_block
= bb
->index
;
4661 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4662 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4664 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4665 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4666 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4667 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4670 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4671 cfg
->x_last_basic_block
, bb
);
4673 /* The statements in BB need to be associated with a new TREE_BLOCK.
4674 Labels need to be associated with a new label-to-block map. */
4675 memset (&d
, 0, sizeof (d
));
4676 d
.vars_to_remove
= vars_to_remove
;
4678 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4680 tree stmt
= bsi_stmt (si
);
4683 d
.from_context
= cfun
->decl
;
4684 d
.to_context
= dest_cfun
->decl
;
4685 d
.remap_decls_p
= true;
4686 d
.new_label_map
= new_label_map
;
4687 if (TREE_BLOCK (stmt
))
4688 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4690 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4692 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4694 tree label
= LABEL_EXPR_LABEL (stmt
);
4695 int uid
= LABEL_DECL_UID (label
);
4697 gcc_assert (uid
> -1);
4699 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4700 if (old_len
<= (unsigned) uid
)
4702 new_len
= 3 * uid
/ 2;
4703 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4705 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4706 memset (&addr
[old_len
], 0,
4707 sizeof (basic_block
) * (new_len
- old_len
));
4710 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4711 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4713 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4715 if (uid
>= dest_cfun
->last_label_uid
)
4716 dest_cfun
->last_label_uid
= uid
+ 1;
4718 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4719 TREE_OPERAND (stmt
, 0) =
4720 build_int_cst (NULL_TREE
,
4721 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4724 region
= lookup_stmt_eh_region (stmt
);
4727 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4728 remove_stmt_from_eh_region (stmt
);
4733 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4734 the outermost EH region. Use REGION as the incoming base EH region. */
4737 find_outermost_region_in_block (struct function
*src_cfun
,
4738 basic_block bb
, int region
)
4740 block_stmt_iterator si
;
4742 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4744 tree stmt
= bsi_stmt (si
);
4747 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4748 if (stmt_region
> 0)
4751 region
= stmt_region
;
4752 else if (stmt_region
!= region
)
4754 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4755 gcc_assert (region
!= -1);
4764 new_label_mapper (tree decl
, void *data
)
4766 htab_t hash
= (htab_t
) data
;
4770 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4772 m
= xmalloc (sizeof (struct tree_map
));
4773 m
->hash
= DECL_UID (decl
);
4775 m
->to
= create_artificial_label ();
4776 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4778 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4779 gcc_assert (*slot
== NULL
);
4786 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4787 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4788 single basic block in the original CFG and the new basic block is
4789 returned. DEST_CFUN must not have a CFG yet.
4791 Note that the region need not be a pure SESE region. Blocks inside
4792 the region may contain calls to abort/exit. The only restriction
4793 is that ENTRY_BB should be the only entry point and it must
4796 All local variables referenced in the region are assumed to be in
4797 the corresponding BLOCK_VARS and unexpanded variable lists
4798 associated with DEST_CFUN. */
4801 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4802 basic_block exit_bb
)
4804 VEC(basic_block
,heap
) *bbs
;
4805 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4806 struct function
*saved_cfun
;
4807 int *entry_flag
, *exit_flag
, eh_offset
;
4808 unsigned i
, num_entry_edges
, num_exit_edges
;
4811 bitmap vars_to_remove
;
4812 htab_t new_label_map
;
4816 /* Collect all the blocks in the region. Manually add ENTRY_BB
4817 because it won't be added by dfs_enumerate_from. */
4818 calculate_dominance_info (CDI_DOMINATORS
);
4820 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4822 gcc_assert (entry_bb
!= exit_bb
4823 && dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
));
4826 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4827 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4829 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4830 the predecessor edges to ENTRY_BB and the successor edges to
4831 EXIT_BB so that we can re-attach them to the new basic block that
4832 will replace the region. */
4833 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4834 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4835 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4837 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4839 entry_flag
[i
] = e
->flags
;
4840 entry_pred
[i
++] = e
->src
;
4844 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4845 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
, sizeof (basic_block
));
4846 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4848 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4850 exit_flag
[i
] = e
->flags
;
4851 exit_succ
[i
++] = e
->dest
;
4855 /* Switch context to the child function to initialize DEST_FN's CFG. */
4856 gcc_assert (dest_cfun
->cfg
== NULL
);
4859 init_empty_tree_cfg ();
4861 /* Initialize EH information for the new function. */
4863 new_label_map
= NULL
;
4868 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4869 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4871 init_eh_for_function ();
4874 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4875 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4876 new_label_map
, region
, 0);
4882 /* Move blocks from BBS into DEST_CFUN. */
4883 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4884 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4885 vars_to_remove
= BITMAP_ALLOC (NULL
);
4886 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4888 /* No need to update edge counts on the last block. It has
4889 already been updated earlier when we detached the region from
4890 the original CFG. */
4891 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4892 new_label_map
, eh_offset
);
4897 htab_delete (new_label_map
);
4899 /* Remove the variables marked in VARS_TO_REMOVE from
4900 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4901 DECL_RTL in the context of CFUN. */
4902 if (!bitmap_empty_p (vars_to_remove
))
4906 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4908 tree var
= TREE_VALUE (*p
);
4909 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4911 *p
= TREE_CHAIN (*p
);
4915 p
= &TREE_CHAIN (*p
);
4919 BITMAP_FREE (vars_to_remove
);
4921 /* Rewire the entry and exit blocks. The successor to the entry
4922 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4923 the child function. Similarly, the predecessor of DEST_FN's
4924 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4925 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4926 various CFG manipulation function get to the right CFG.
4928 FIXME, this is silly. The CFG ought to become a parameter to
4931 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4932 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4935 /* Back in the original function, the SESE region has disappeared,
4936 create a new basic block in its place. */
4937 bb
= create_empty_bb (entry_pred
[0]);
4938 for (i
= 0; i
< num_entry_edges
; i
++)
4939 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4941 for (i
= 0; i
< num_exit_edges
; i
++)
4942 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4948 free_dominance_info (CDI_DOMINATORS
);
4949 free_dominance_info (CDI_POST_DOMINATORS
);
4950 VEC_free (basic_block
, heap
, bbs
);
4956 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4959 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4961 tree arg
, vars
, var
;
4962 bool ignore_topmost_bind
= false, any_var
= false;
4965 struct function
*saved_cfun
;
4967 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4969 arg
= DECL_ARGUMENTS (fn
);
4972 print_generic_expr (file
, arg
, dump_flags
);
4973 if (TREE_CHAIN (arg
))
4974 fprintf (file
, ", ");
4975 arg
= TREE_CHAIN (arg
);
4977 fprintf (file
, ")\n");
4979 if (flags
& TDF_DETAILS
)
4980 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4981 if (flags
& TDF_RAW
)
4983 dump_node (fn
, TDF_SLIM
| flags
, file
);
4987 /* Switch CFUN to point to FN. */
4989 cfun
= DECL_STRUCT_FUNCTION (fn
);
4991 /* When GIMPLE is lowered, the variables are no longer available in
4992 BIND_EXPRs, so display them separately. */
4993 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4995 ignore_topmost_bind
= true;
4997 fprintf (file
, "{\n");
4998 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5000 var
= TREE_VALUE (vars
);
5002 print_generic_decl (file
, var
, flags
);
5003 fprintf (file
, "\n");
5009 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5011 /* Make a CFG based dump. */
5012 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5013 if (!ignore_topmost_bind
)
5014 fprintf (file
, "{\n");
5016 if (any_var
&& n_basic_blocks
)
5017 fprintf (file
, "\n");
5020 dump_generic_bb (file
, bb
, 2, flags
);
5022 fprintf (file
, "}\n");
5023 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5029 /* Make a tree based dump. */
5030 chain
= DECL_SAVED_TREE (fn
);
5032 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5034 if (ignore_topmost_bind
)
5036 chain
= BIND_EXPR_BODY (chain
);
5044 if (!ignore_topmost_bind
)
5045 fprintf (file
, "{\n");
5050 fprintf (file
, "\n");
5052 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5053 if (ignore_topmost_bind
)
5054 fprintf (file
, "}\n");
5057 fprintf (file
, "\n\n");
5064 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5067 debug_function (tree fn
, int flags
)
5069 dump_function_to_file (fn
, stderr
, flags
);
5073 /* Pretty print of the loops intermediate representation. */
5074 static void print_loop (FILE *, struct loop
*, int);
5075 static void print_pred_bbs (FILE *, basic_block bb
);
5076 static void print_succ_bbs (FILE *, basic_block bb
);
5079 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5082 print_pred_bbs (FILE *file
, basic_block bb
)
5087 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5088 fprintf (file
, "bb_%d ", e
->src
->index
);
5092 /* Print on FILE the indexes for the successors of basic_block BB. */
5095 print_succ_bbs (FILE *file
, basic_block bb
)
5100 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5101 fprintf (file
, "bb_%d ", e
->dest
->index
);
5105 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5108 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5116 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5117 memset ((void *) s_indent
, ' ', (size_t) indent
);
5118 s_indent
[indent
] = '\0';
5120 /* Print the loop's header. */
5121 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5123 /* Print the loop's body. */
5124 fprintf (file
, "%s{\n", s_indent
);
5126 if (bb
->loop_father
== loop
)
5128 /* Print the basic_block's header. */
5129 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5130 print_pred_bbs (file
, bb
);
5131 fprintf (file
, "}, succs = {");
5132 print_succ_bbs (file
, bb
);
5133 fprintf (file
, "})\n");
5135 /* Print the basic_block's body. */
5136 fprintf (file
, "%s {\n", s_indent
);
5137 tree_dump_bb (bb
, file
, indent
+ 4);
5138 fprintf (file
, "%s }\n", s_indent
);
5141 print_loop (file
, loop
->inner
, indent
+ 2);
5142 fprintf (file
, "%s}\n", s_indent
);
5143 print_loop (file
, loop
->next
, indent
);
5147 /* Follow a CFG edge from the entry point of the program, and on entry
5148 of a loop, pretty print the loop structure on FILE. */
5151 print_loop_ir (FILE *file
)
5155 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5156 if (bb
&& bb
->loop_father
)
5157 print_loop (file
, bb
->loop_father
, 0);
5161 /* Debugging loops structure at tree level. */
5164 debug_loop_ir (void)
5166 print_loop_ir (stderr
);
5170 /* Return true if BB ends with a call, possibly followed by some
5171 instructions that must stay with the call. Return false,
5175 tree_block_ends_with_call_p (basic_block bb
)
5177 block_stmt_iterator bsi
= bsi_last (bb
);
5178 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5182 /* Return true if BB ends with a conditional branch. Return false,
5186 tree_block_ends_with_condjump_p (basic_block bb
)
5188 tree stmt
= last_stmt (bb
);
5189 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5193 /* Return true if we need to add fake edge to exit at statement T.
5194 Helper function for tree_flow_call_edges_add. */
5197 need_fake_edge_p (tree t
)
5201 /* NORETURN and LONGJMP calls already have an edge to exit.
5202 CONST and PURE calls do not need one.
5203 We don't currently check for CONST and PURE here, although
5204 it would be a good idea, because those attributes are
5205 figured out from the RTL in mark_constant_function, and
5206 the counter incrementation code from -fprofile-arcs
5207 leads to different results from -fbranch-probabilities. */
5208 call
= get_call_expr_in (t
);
5210 && !(call_expr_flags (call
) & ECF_NORETURN
))
5213 if (TREE_CODE (t
) == ASM_EXPR
5214 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5221 /* Add fake edges to the function exit for any non constant and non
5222 noreturn calls, volatile inline assembly in the bitmap of blocks
5223 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5224 the number of blocks that were split.
5226 The goal is to expose cases in which entering a basic block does
5227 not imply that all subsequent instructions must be executed. */
5230 tree_flow_call_edges_add (sbitmap blocks
)
5233 int blocks_split
= 0;
5234 int last_bb
= last_basic_block
;
5235 bool check_last_block
= false;
5237 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5241 check_last_block
= true;
5243 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5245 /* In the last basic block, before epilogue generation, there will be
5246 a fallthru edge to EXIT. Special care is required if the last insn
5247 of the last basic block is a call because make_edge folds duplicate
5248 edges, which would result in the fallthru edge also being marked
5249 fake, which would result in the fallthru edge being removed by
5250 remove_fake_edges, which would result in an invalid CFG.
5252 Moreover, we can't elide the outgoing fake edge, since the block
5253 profiler needs to take this into account in order to solve the minimal
5254 spanning tree in the case that the call doesn't return.
5256 Handle this by adding a dummy instruction in a new last basic block. */
5257 if (check_last_block
)
5259 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5260 block_stmt_iterator bsi
= bsi_last (bb
);
5262 if (!bsi_end_p (bsi
))
5265 if (t
&& need_fake_edge_p (t
))
5269 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5272 bsi_insert_on_edge (e
, build_empty_stmt ());
5273 bsi_commit_edge_inserts ();
5278 /* Now add fake edges to the function exit for any non constant
5279 calls since there is no way that we can determine if they will
5281 for (i
= 0; i
< last_bb
; i
++)
5283 basic_block bb
= BASIC_BLOCK (i
);
5284 block_stmt_iterator bsi
;
5285 tree stmt
, last_stmt
;
5290 if (blocks
&& !TEST_BIT (blocks
, i
))
5293 bsi
= bsi_last (bb
);
5294 if (!bsi_end_p (bsi
))
5296 last_stmt
= bsi_stmt (bsi
);
5299 stmt
= bsi_stmt (bsi
);
5300 if (need_fake_edge_p (stmt
))
5303 /* The handling above of the final block before the
5304 epilogue should be enough to verify that there is
5305 no edge to the exit block in CFG already.
5306 Calling make_edge in such case would cause us to
5307 mark that edge as fake and remove it later. */
5308 #ifdef ENABLE_CHECKING
5309 if (stmt
== last_stmt
)
5311 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5312 gcc_assert (e
== NULL
);
5316 /* Note that the following may create a new basic block
5317 and renumber the existing basic blocks. */
5318 if (stmt
!= last_stmt
)
5320 e
= split_block (bb
, stmt
);
5324 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5328 while (!bsi_end_p (bsi
));
5333 verify_flow_info ();
5335 return blocks_split
;
5339 tree_purge_dead_eh_edges (basic_block bb
)
5341 bool changed
= false;
5344 tree stmt
= last_stmt (bb
);
5346 if (stmt
&& tree_can_throw_internal (stmt
))
5349 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5351 if (e
->flags
& EDGE_EH
)
5360 /* Removal of dead EH edges might change dominators of not
5361 just immediate successors. E.g. when bb1 is changed so that
5362 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5363 eh edges purged by this function in:
5375 idom(bb5) must be recomputed. For now just free the dominance
5378 free_dominance_info (CDI_DOMINATORS
);
5384 tree_purge_all_dead_eh_edges (bitmap blocks
)
5386 bool changed
= false;
5390 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5392 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5398 /* This function is called whenever a new edge is created or
5402 tree_execute_on_growing_pred (edge e
)
5404 basic_block bb
= e
->dest
;
5407 reserve_phi_args_for_new_edge (bb
);
5410 /* This function is called immediately before edge E is removed from
5411 the edge vector E->dest->preds. */
5414 tree_execute_on_shrinking_pred (edge e
)
5416 if (phi_nodes (e
->dest
))
5417 remove_phi_args (e
);
5420 /*---------------------------------------------------------------------------
5421 Helper functions for Loop versioning
5422 ---------------------------------------------------------------------------*/
5424 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5425 of 'first'. Both of them are dominated by 'new_head' basic block. When
5426 'new_head' was created by 'second's incoming edge it received phi arguments
5427 on the edge by split_edge(). Later, additional edge 'e' was created to
5428 connect 'new_head' and 'first'. Now this routine adds phi args on this
5429 additional edge 'e' that new_head to second edge received as part of edge
5434 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5435 basic_block new_head
, edge e
)
5438 edge e2
= find_edge (new_head
, second
);
5440 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5441 edge, we should always have an edge from NEW_HEAD to SECOND. */
5442 gcc_assert (e2
!= NULL
);
5444 /* Browse all 'second' basic block phi nodes and add phi args to
5445 edge 'e' for 'first' head. PHI args are always in correct order. */
5447 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5449 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5451 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5452 add_phi_arg (phi1
, def
, e
);
5456 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5457 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5458 the destination of the ELSE part. */
5460 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5461 basic_block cond_bb
, void *cond_e
)
5463 block_stmt_iterator bsi
;
5464 tree goto1
= NULL_TREE
;
5465 tree goto2
= NULL_TREE
;
5466 tree new_cond_expr
= NULL_TREE
;
5467 tree cond_expr
= (tree
) cond_e
;
5470 /* Build new conditional expr */
5471 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5472 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5473 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5475 /* Add new cond in cond_bb. */
5476 bsi
= bsi_start (cond_bb
);
5477 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5478 /* Adjust edges appropriately to connect new head with first head
5479 as well as second head. */
5480 e0
= single_succ_edge (cond_bb
);
5481 e0
->flags
&= ~EDGE_FALLTHRU
;
5482 e0
->flags
|= EDGE_FALSE_VALUE
;
5485 struct cfg_hooks tree_cfg_hooks
= {
5487 tree_verify_flow_info
,
5488 tree_dump_bb
, /* dump_bb */
5489 create_bb
, /* create_basic_block */
5490 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5491 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5492 remove_bb
, /* delete_basic_block */
5493 tree_split_block
, /* split_block */
5494 tree_move_block_after
, /* move_block_after */
5495 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5496 tree_merge_blocks
, /* merge_blocks */
5497 tree_predict_edge
, /* predict_edge */
5498 tree_predicted_by_p
, /* predicted_by_p */
5499 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5500 tree_duplicate_bb
, /* duplicate_block */
5501 tree_split_edge
, /* split_edge */
5502 tree_make_forwarder_block
, /* make_forward_block */
5503 NULL
, /* tidy_fallthru_edge */
5504 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5505 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5506 tree_flow_call_edges_add
, /* flow_call_edges_add */
5507 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5508 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5509 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5510 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5511 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5512 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5513 flush_pending_stmts
/* flush_pending_stmts */
5517 /* Split all critical edges. */
5520 split_critical_edges (void)
5526 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5527 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5528 mappings around the calls to split_edge. */
5529 start_recording_case_labels ();
5532 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5533 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5538 end_recording_case_labels ();
5542 struct tree_opt_pass pass_split_crit_edges
=
5544 "crited", /* name */
5546 split_critical_edges
, /* execute */
5549 0, /* static_pass_number */
5550 TV_TREE_SPLIT_EDGES
, /* tv_id */
5551 PROP_cfg
, /* properties required */
5552 PROP_no_crit_edges
, /* properties_provided */
5553 0, /* properties_destroyed */
5554 0, /* todo_flags_start */
5555 TODO_dump_func
, /* todo_flags_finish */
5560 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5561 a temporary, make sure and register it to be renamed if necessary,
5562 and finally return the temporary. Put the statements to compute
5563 EXP before the current statement in BSI. */
5566 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5568 tree t
, new_stmt
, orig_stmt
;
5570 if (is_gimple_val (exp
))
5573 t
= make_rename_temp (type
, NULL
);
5574 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5576 orig_stmt
= bsi_stmt (*bsi
);
5577 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5578 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5580 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5585 /* Build a ternary operation and gimplify it. Emit code before BSI.
5586 Return the gimple_val holding the result. */
5589 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5590 tree type
, tree a
, tree b
, tree c
)
5594 ret
= fold_build3 (code
, type
, a
, b
, c
);
5597 return gimplify_val (bsi
, type
, ret
);
5600 /* Build a binary operation and gimplify it. Emit code before BSI.
5601 Return the gimple_val holding the result. */
5604 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5605 tree type
, tree a
, tree b
)
5609 ret
= fold_build2 (code
, type
, a
, b
);
5612 return gimplify_val (bsi
, type
, ret
);
5615 /* Build a unary operation and gimplify it. Emit code before BSI.
5616 Return the gimple_val holding the result. */
5619 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5624 ret
= fold_build1 (code
, type
, a
);
5627 return gimplify_val (bsi
, type
, ret
);
5632 /* Emit return warnings. */
5635 execute_warn_function_return (void)
5637 #ifdef USE_MAPPED_LOCATION
5638 source_location location
;
5646 /* If we have a path to EXIT, then we do return. */
5647 if (TREE_THIS_VOLATILE (cfun
->decl
)
5648 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5650 #ifdef USE_MAPPED_LOCATION
5651 location
= UNKNOWN_LOCATION
;
5655 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5657 last
= last_stmt (e
->src
);
5658 if (TREE_CODE (last
) == RETURN_EXPR
5659 #ifdef USE_MAPPED_LOCATION
5660 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5662 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5666 #ifdef USE_MAPPED_LOCATION
5667 if (location
== UNKNOWN_LOCATION
)
5668 location
= cfun
->function_end_locus
;
5669 warning (0, "%H%<noreturn%> function does return", &location
);
5672 locus
= &cfun
->function_end_locus
;
5673 warning (0, "%H%<noreturn%> function does return", locus
);
5677 /* If we see "return;" in some basic block, then we do reach the end
5678 without returning a value. */
5679 else if (warn_return_type
5680 && !TREE_NO_WARNING (cfun
->decl
)
5681 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5682 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5684 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5686 tree last
= last_stmt (e
->src
);
5687 if (TREE_CODE (last
) == RETURN_EXPR
5688 && TREE_OPERAND (last
, 0) == NULL
5689 && !TREE_NO_WARNING (last
))
5691 #ifdef USE_MAPPED_LOCATION
5692 location
= EXPR_LOCATION (last
);
5693 if (location
== UNKNOWN_LOCATION
)
5694 location
= cfun
->function_end_locus
;
5695 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5697 locus
= EXPR_LOCUS (last
);
5699 locus
= &cfun
->function_end_locus
;
5700 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5702 TREE_NO_WARNING (cfun
->decl
) = 1;
5711 /* Given a basic block B which ends with a conditional and has
5712 precisely two successors, determine which of the edges is taken if
5713 the conditional is true and which is taken if the conditional is
5714 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5717 extract_true_false_edges_from_block (basic_block b
,
5721 edge e
= EDGE_SUCC (b
, 0);
5723 if (e
->flags
& EDGE_TRUE_VALUE
)
5726 *false_edge
= EDGE_SUCC (b
, 1);
5731 *true_edge
= EDGE_SUCC (b
, 1);
5735 struct tree_opt_pass pass_warn_function_return
=
5739 execute_warn_function_return
, /* execute */
5742 0, /* static_pass_number */
5744 PROP_cfg
, /* properties_required */
5745 0, /* properties_provided */
5746 0, /* properties_destroyed */
5747 0, /* todo_flags_start */
5748 0, /* todo_flags_finish */
5752 /* Emit noreturn warnings. */
5755 execute_warn_function_noreturn (void)
5757 if (warn_missing_noreturn
5758 && !TREE_THIS_VOLATILE (cfun
->decl
)
5759 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5760 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5761 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5762 "for attribute %<noreturn%>",
5767 struct tree_opt_pass pass_warn_function_noreturn
=
5771 execute_warn_function_noreturn
, /* execute */
5774 0, /* static_pass_number */
5776 PROP_cfg
, /* properties_required */
5777 0, /* properties_provided */
5778 0, /* properties_destroyed */
5779 0, /* todo_flags_start */
5780 0, /* todo_flags_finish */