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
;
1264 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, name
)
1266 FOR_EACH_IMM_USE_ON_STMT (use
, imm_iter
)
1268 replace_exp (use
, val
);
1270 if (TREE_CODE (stmt
) == PHI_NODE
)
1272 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1273 if (e
->flags
& EDGE_ABNORMAL
)
1275 /* This can only occur for virtual operands, since
1276 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1277 would prevent replacement. */
1278 gcc_assert (!is_gimple_reg (name
));
1279 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1283 if (TREE_CODE (stmt
) != PHI_NODE
)
1287 fold_stmt_inplace (stmt
);
1288 rhs
= get_rhs (stmt
);
1289 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1290 recompute_tree_invariant_for_addr_expr (rhs
);
1292 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1293 mark_new_vars_to_rename (stmt
);
1297 gcc_assert (num_imm_uses (name
) == 0);
1299 /* Also update the trees stored in loop structures. */
1304 for (i
= 0; i
< current_loops
->num
; i
++)
1306 loop
= current_loops
->parray
[i
];
1308 substitute_in_loop_info (loop
, name
, val
);
1313 /* Merge block B into block A. */
1316 tree_merge_blocks (basic_block a
, basic_block b
)
1318 block_stmt_iterator bsi
;
1319 tree_stmt_iterator last
;
1323 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1325 /* Remove all single-valued PHI nodes from block B of the form
1326 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1328 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1330 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1332 bool may_replace_uses
= may_propagate_copy (def
, use
);
1334 /* In case we have loops to care about, do not propagate arguments of
1335 loop closed ssa phi nodes. */
1337 && is_gimple_reg (def
)
1338 && TREE_CODE (use
) == SSA_NAME
1339 && a
->loop_father
!= b
->loop_father
)
1340 may_replace_uses
= false;
1342 if (!may_replace_uses
)
1344 gcc_assert (is_gimple_reg (def
));
1346 /* Note that just emitting the copies is fine -- there is no problem
1347 with ordering of phi nodes. This is because A is the single
1348 predecessor of B, therefore results of the phi nodes cannot
1349 appear as arguments of the phi nodes. */
1350 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1351 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1352 SET_PHI_RESULT (phi
, NULL_TREE
);
1353 SSA_NAME_DEF_STMT (def
) = copy
;
1356 replace_uses_by (def
, use
);
1358 remove_phi_node (phi
, NULL
);
1361 /* Ensure that B follows A. */
1362 move_block_after (b
, a
);
1364 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1365 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1367 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1368 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1370 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1372 tree label
= bsi_stmt (bsi
);
1374 bsi_remove (&bsi
, false);
1375 /* Now that we can thread computed gotos, we might have
1376 a situation where we have a forced label in block B
1377 However, the label at the start of block B might still be
1378 used in other ways (think about the runtime checking for
1379 Fortran assigned gotos). So we can not just delete the
1380 label. Instead we move the label to the start of block A. */
1381 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1383 block_stmt_iterator dest_bsi
= bsi_start (a
);
1384 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1389 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1394 /* Merge the chains. */
1395 last
= tsi_last (a
->stmt_list
);
1396 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1397 b
->stmt_list
= NULL
;
1401 /* Return the one of two successors of BB that is not reachable by a
1402 reached by a complex edge, if there is one. Else, return BB. We use
1403 this in optimizations that use post-dominators for their heuristics,
1404 to catch the cases in C++ where function calls are involved. */
1407 single_noncomplex_succ (basic_block bb
)
1410 if (EDGE_COUNT (bb
->succs
) != 2)
1413 e0
= EDGE_SUCC (bb
, 0);
1414 e1
= EDGE_SUCC (bb
, 1);
1415 if (e0
->flags
& EDGE_COMPLEX
)
1417 if (e1
->flags
& EDGE_COMPLEX
)
1424 /* Walk the function tree removing unnecessary statements.
1426 * Empty statement nodes are removed
1428 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1430 * Unnecessary COND_EXPRs are removed
1432 * Some unnecessary BIND_EXPRs are removed
1434 Clearly more work could be done. The trick is doing the analysis
1435 and removal fast enough to be a net improvement in compile times.
1437 Note that when we remove a control structure such as a COND_EXPR
1438 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1439 to ensure we eliminate all the useless code. */
1450 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1453 remove_useless_stmts_warn_notreached (tree stmt
)
1455 if (EXPR_HAS_LOCATION (stmt
))
1457 location_t loc
= EXPR_LOCATION (stmt
);
1458 if (LOCATION_LINE (loc
) > 0)
1460 warning (0, "%Hwill never be executed", &loc
);
1465 switch (TREE_CODE (stmt
))
1467 case STATEMENT_LIST
:
1469 tree_stmt_iterator i
;
1470 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1471 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1477 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1479 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1481 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1485 case TRY_FINALLY_EXPR
:
1486 case TRY_CATCH_EXPR
:
1487 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1489 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1494 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1495 case EH_FILTER_EXPR
:
1496 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1498 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1501 /* Not a live container. */
1509 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1511 tree then_clause
, else_clause
, cond
;
1512 bool save_has_label
, then_has_label
, else_has_label
;
1514 save_has_label
= data
->has_label
;
1515 data
->has_label
= false;
1516 data
->last_goto
= NULL
;
1518 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1520 then_has_label
= data
->has_label
;
1521 data
->has_label
= false;
1522 data
->last_goto
= NULL
;
1524 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1526 else_has_label
= data
->has_label
;
1527 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1529 then_clause
= COND_EXPR_THEN (*stmt_p
);
1530 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1531 cond
= fold (COND_EXPR_COND (*stmt_p
));
1533 /* If neither arm does anything at all, we can remove the whole IF. */
1534 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1536 *stmt_p
= build_empty_stmt ();
1537 data
->repeat
= true;
1540 /* If there are no reachable statements in an arm, then we can
1541 zap the entire conditional. */
1542 else if (integer_nonzerop (cond
) && !else_has_label
)
1544 if (warn_notreached
)
1545 remove_useless_stmts_warn_notreached (else_clause
);
1546 *stmt_p
= then_clause
;
1547 data
->repeat
= true;
1549 else if (integer_zerop (cond
) && !then_has_label
)
1551 if (warn_notreached
)
1552 remove_useless_stmts_warn_notreached (then_clause
);
1553 *stmt_p
= else_clause
;
1554 data
->repeat
= true;
1557 /* Check a couple of simple things on then/else with single stmts. */
1560 tree then_stmt
= expr_only (then_clause
);
1561 tree else_stmt
= expr_only (else_clause
);
1563 /* Notice branches to a common destination. */
1564 if (then_stmt
&& else_stmt
1565 && TREE_CODE (then_stmt
) == GOTO_EXPR
1566 && TREE_CODE (else_stmt
) == GOTO_EXPR
1567 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1569 *stmt_p
= then_stmt
;
1570 data
->repeat
= true;
1573 /* If the THEN/ELSE clause merely assigns a value to a variable or
1574 parameter which is already known to contain that value, then
1575 remove the useless THEN/ELSE clause. */
1576 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1579 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1580 && TREE_OPERAND (else_stmt
, 0) == cond
1581 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1582 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1584 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1585 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1586 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1587 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1589 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1590 ? then_stmt
: else_stmt
);
1591 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1592 ? &COND_EXPR_THEN (*stmt_p
)
1593 : &COND_EXPR_ELSE (*stmt_p
));
1596 && TREE_CODE (stmt
) == MODIFY_EXPR
1597 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1598 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1599 *location
= alloc_stmt_list ();
1603 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1604 would be re-introduced during lowering. */
1605 data
->last_goto
= NULL
;
1610 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1612 bool save_may_branch
, save_may_throw
;
1613 bool this_may_branch
, this_may_throw
;
1615 /* Collect may_branch and may_throw information for the body only. */
1616 save_may_branch
= data
->may_branch
;
1617 save_may_throw
= data
->may_throw
;
1618 data
->may_branch
= false;
1619 data
->may_throw
= false;
1620 data
->last_goto
= NULL
;
1622 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1624 this_may_branch
= data
->may_branch
;
1625 this_may_throw
= data
->may_throw
;
1626 data
->may_branch
|= save_may_branch
;
1627 data
->may_throw
|= save_may_throw
;
1628 data
->last_goto
= NULL
;
1630 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1632 /* If the body is empty, then we can emit the FINALLY block without
1633 the enclosing TRY_FINALLY_EXPR. */
1634 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1636 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1637 data
->repeat
= true;
1640 /* If the handler is empty, then we can emit the TRY block without
1641 the enclosing TRY_FINALLY_EXPR. */
1642 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1644 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1645 data
->repeat
= true;
1648 /* If the body neither throws, nor branches, then we can safely
1649 string the TRY and FINALLY blocks together. */
1650 else if (!this_may_branch
&& !this_may_throw
)
1652 tree stmt
= *stmt_p
;
1653 *stmt_p
= TREE_OPERAND (stmt
, 0);
1654 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1655 data
->repeat
= true;
1661 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1663 bool save_may_throw
, this_may_throw
;
1664 tree_stmt_iterator i
;
1667 /* Collect may_throw information for the body only. */
1668 save_may_throw
= data
->may_throw
;
1669 data
->may_throw
= false;
1670 data
->last_goto
= NULL
;
1672 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1674 this_may_throw
= data
->may_throw
;
1675 data
->may_throw
= save_may_throw
;
1677 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1678 if (!this_may_throw
)
1680 if (warn_notreached
)
1681 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1682 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1683 data
->repeat
= true;
1687 /* Process the catch clause specially. We may be able to tell that
1688 no exceptions propagate past this point. */
1690 this_may_throw
= true;
1691 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1692 stmt
= tsi_stmt (i
);
1693 data
->last_goto
= NULL
;
1695 switch (TREE_CODE (stmt
))
1698 for (; !tsi_end_p (i
); tsi_next (&i
))
1700 stmt
= tsi_stmt (i
);
1701 /* If we catch all exceptions, then the body does not
1702 propagate exceptions past this point. */
1703 if (CATCH_TYPES (stmt
) == NULL
)
1704 this_may_throw
= false;
1705 data
->last_goto
= NULL
;
1706 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1710 case EH_FILTER_EXPR
:
1711 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1712 this_may_throw
= false;
1713 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1714 this_may_throw
= false;
1715 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1719 /* Otherwise this is a cleanup. */
1720 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1722 /* If the cleanup is empty, then we can emit the TRY block without
1723 the enclosing TRY_CATCH_EXPR. */
1724 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1726 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1727 data
->repeat
= true;
1731 data
->may_throw
|= this_may_throw
;
1736 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1740 /* First remove anything underneath the BIND_EXPR. */
1741 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1743 /* If the BIND_EXPR has no variables, then we can pull everything
1744 up one level and remove the BIND_EXPR, unless this is the toplevel
1745 BIND_EXPR for the current function or an inlined function.
1747 When this situation occurs we will want to apply this
1748 optimization again. */
1749 block
= BIND_EXPR_BLOCK (*stmt_p
);
1750 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1751 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1753 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1754 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1757 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1758 data
->repeat
= true;
1764 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1766 tree dest
= GOTO_DESTINATION (*stmt_p
);
1768 data
->may_branch
= true;
1769 data
->last_goto
= NULL
;
1771 /* Record the last goto expr, so that we can delete it if unnecessary. */
1772 if (TREE_CODE (dest
) == LABEL_DECL
)
1773 data
->last_goto
= stmt_p
;
1778 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1780 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1782 data
->has_label
= true;
1784 /* We do want to jump across non-local label receiver code. */
1785 if (DECL_NONLOCAL (label
))
1786 data
->last_goto
= NULL
;
1788 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1790 *data
->last_goto
= build_empty_stmt ();
1791 data
->repeat
= true;
1794 /* ??? Add something here to delete unused labels. */
1798 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1799 decl. This allows us to eliminate redundant or useless
1800 calls to "const" functions.
1802 Gimplifier already does the same operation, but we may notice functions
1803 being const and pure once their calls has been gimplified, so we need
1804 to update the flag. */
1807 update_call_expr_flags (tree call
)
1809 tree decl
= get_callee_fndecl (call
);
1812 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1813 TREE_SIDE_EFFECTS (call
) = 0;
1814 if (TREE_NOTHROW (decl
))
1815 TREE_NOTHROW (call
) = 1;
1819 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1822 notice_special_calls (tree t
)
1824 int flags
= call_expr_flags (t
);
1826 if (flags
& ECF_MAY_BE_ALLOCA
)
1827 current_function_calls_alloca
= true;
1828 if (flags
& ECF_RETURNS_TWICE
)
1829 current_function_calls_setjmp
= true;
1833 /* Clear flags set by notice_special_calls. Used by dead code removal
1834 to update the flags. */
1837 clear_special_calls (void)
1839 current_function_calls_alloca
= false;
1840 current_function_calls_setjmp
= false;
1845 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1849 switch (TREE_CODE (t
))
1852 remove_useless_stmts_cond (tp
, data
);
1855 case TRY_FINALLY_EXPR
:
1856 remove_useless_stmts_tf (tp
, data
);
1859 case TRY_CATCH_EXPR
:
1860 remove_useless_stmts_tc (tp
, data
);
1864 remove_useless_stmts_bind (tp
, data
);
1868 remove_useless_stmts_goto (tp
, data
);
1872 remove_useless_stmts_label (tp
, data
);
1877 data
->last_goto
= NULL
;
1878 data
->may_branch
= true;
1883 data
->last_goto
= NULL
;
1884 notice_special_calls (t
);
1885 update_call_expr_flags (t
);
1886 if (tree_could_throw_p (t
))
1887 data
->may_throw
= true;
1891 data
->last_goto
= NULL
;
1893 op
= get_call_expr_in (t
);
1896 update_call_expr_flags (op
);
1897 notice_special_calls (op
);
1899 if (tree_could_throw_p (t
))
1900 data
->may_throw
= true;
1903 case STATEMENT_LIST
:
1905 tree_stmt_iterator i
= tsi_start (t
);
1906 while (!tsi_end_p (i
))
1909 if (IS_EMPTY_STMT (t
))
1915 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1918 if (TREE_CODE (t
) == STATEMENT_LIST
)
1920 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1930 data
->last_goto
= NULL
;
1934 data
->last_goto
= NULL
;
1940 remove_useless_stmts (void)
1942 struct rus_data data
;
1944 clear_special_calls ();
1948 memset (&data
, 0, sizeof (data
));
1949 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1951 while (data
.repeat
);
1956 struct tree_opt_pass pass_remove_useless_stmts
=
1958 "useless", /* name */
1960 remove_useless_stmts
, /* execute */
1963 0, /* static_pass_number */
1965 PROP_gimple_any
, /* properties_required */
1966 0, /* properties_provided */
1967 0, /* properties_destroyed */
1968 0, /* todo_flags_start */
1969 TODO_dump_func
, /* todo_flags_finish */
1973 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1976 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1980 /* Since this block is no longer reachable, we can just delete all
1981 of its PHI nodes. */
1982 phi
= phi_nodes (bb
);
1985 tree next
= PHI_CHAIN (phi
);
1986 remove_phi_node (phi
, NULL_TREE
);
1990 /* Remove edges to BB's successors. */
1991 while (EDGE_COUNT (bb
->succs
) > 0)
1992 remove_edge (EDGE_SUCC (bb
, 0));
1996 /* Remove statements of basic block BB. */
1999 remove_bb (basic_block bb
)
2001 block_stmt_iterator i
;
2002 #ifdef USE_MAPPED_LOCATION
2003 source_location loc
= UNKNOWN_LOCATION
;
2005 source_locus loc
= 0;
2010 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2011 if (dump_flags
& TDF_DETAILS
)
2013 dump_bb (bb
, dump_file
, 0);
2014 fprintf (dump_file
, "\n");
2018 /* If we remove the header or the latch of a loop, mark the loop for
2019 removal by setting its header and latch to NULL. */
2022 struct loop
*loop
= bb
->loop_father
;
2024 if (loop
->latch
== bb
2025 || loop
->header
== bb
)
2028 loop
->header
= NULL
;
2030 /* Also clean up the information associated with the loop. Updating
2031 it would waste time. More importantly, it may refer to ssa
2032 names that were defined in other removed basic block -- these
2033 ssa names are now removed and invalid. */
2034 free_numbers_of_iterations_estimates_loop (loop
);
2038 /* Remove all the instructions in the block. */
2039 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2041 tree stmt
= bsi_stmt (i
);
2042 if (TREE_CODE (stmt
) == LABEL_EXPR
2043 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2044 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2047 block_stmt_iterator new_bsi
;
2049 /* A non-reachable non-local label may still be referenced.
2050 But it no longer needs to carry the extra semantics of
2052 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2054 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2055 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2058 new_bb
= bb
->prev_bb
;
2059 new_bsi
= bsi_start (new_bb
);
2060 bsi_remove (&i
, false);
2061 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2065 /* Release SSA definitions if we are in SSA. Note that we
2066 may be called when not in SSA. For example,
2067 final_cleanup calls this function via
2068 cleanup_tree_cfg. */
2070 release_defs (stmt
);
2072 bsi_remove (&i
, true);
2075 /* Don't warn for removed gotos. Gotos are often removed due to
2076 jump threading, thus resulting in bogus warnings. Not great,
2077 since this way we lose warnings for gotos in the original
2078 program that are indeed unreachable. */
2079 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2081 #ifdef USE_MAPPED_LOCATION
2082 if (EXPR_HAS_LOCATION (stmt
))
2083 loc
= EXPR_LOCATION (stmt
);
2086 t
= EXPR_LOCUS (stmt
);
2087 if (t
&& LOCATION_LINE (*t
) > 0)
2093 /* If requested, give a warning that the first statement in the
2094 block is unreachable. We walk statements backwards in the
2095 loop above, so the last statement we process is the first statement
2097 #ifdef USE_MAPPED_LOCATION
2098 if (loc
> BUILTINS_LOCATION
)
2099 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2102 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2105 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2109 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2110 predicate VAL, return the edge that will be taken out of the block.
2111 If VAL does not match a unique edge, NULL is returned. */
2114 find_taken_edge (basic_block bb
, tree val
)
2118 stmt
= last_stmt (bb
);
2121 gcc_assert (is_ctrl_stmt (stmt
));
2124 if (! is_gimple_min_invariant (val
))
2127 if (TREE_CODE (stmt
) == COND_EXPR
)
2128 return find_taken_edge_cond_expr (bb
, val
);
2130 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2131 return find_taken_edge_switch_expr (bb
, val
);
2133 if (computed_goto_p (stmt
))
2134 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2139 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2140 statement, determine which of the outgoing edges will be taken out of the
2141 block. Return NULL if either edge may be taken. */
2144 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2149 dest
= label_to_block (val
);
2152 e
= find_edge (bb
, dest
);
2153 gcc_assert (e
!= NULL
);
2159 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2160 statement, determine which of the two edges will be taken out of the
2161 block. Return NULL if either edge may be taken. */
2164 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2166 edge true_edge
, false_edge
;
2168 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2170 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2171 return (zero_p (val
) ? false_edge
: true_edge
);
2174 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2175 statement, determine which edge will be taken out of the block. Return
2176 NULL if any edge may be taken. */
2179 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2181 tree switch_expr
, taken_case
;
2182 basic_block dest_bb
;
2185 switch_expr
= last_stmt (bb
);
2186 taken_case
= find_case_label_for_value (switch_expr
, val
);
2187 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2189 e
= find_edge (bb
, dest_bb
);
2195 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2196 We can make optimal use here of the fact that the case labels are
2197 sorted: We can do a binary search for a case matching VAL. */
2200 find_case_label_for_value (tree switch_expr
, tree val
)
2202 tree vec
= SWITCH_LABELS (switch_expr
);
2203 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2204 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2206 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2208 size_t i
= (high
+ low
) / 2;
2209 tree t
= TREE_VEC_ELT (vec
, i
);
2212 /* Cache the result of comparing CASE_LOW and val. */
2213 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2220 if (CASE_HIGH (t
) == NULL
)
2222 /* A singe-valued case label. */
2228 /* A case range. We can only handle integer ranges. */
2229 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2234 return default_case
;
2240 /*---------------------------------------------------------------------------
2242 ---------------------------------------------------------------------------*/
2244 /* Dump tree-specific information of block BB to file OUTF. */
2247 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2249 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2253 /* Dump a basic block on stderr. */
2256 debug_tree_bb (basic_block bb
)
2258 dump_bb (bb
, stderr
, 0);
2262 /* Dump basic block with index N on stderr. */
2265 debug_tree_bb_n (int n
)
2267 debug_tree_bb (BASIC_BLOCK (n
));
2268 return BASIC_BLOCK (n
);
2272 /* Dump the CFG on stderr.
2274 FLAGS are the same used by the tree dumping functions
2275 (see TDF_* in tree-pass.h). */
2278 debug_tree_cfg (int flags
)
2280 dump_tree_cfg (stderr
, flags
);
2284 /* Dump the program showing basic block boundaries on the given FILE.
2286 FLAGS are the same used by the tree dumping functions (see TDF_* in
2290 dump_tree_cfg (FILE *file
, int flags
)
2292 if (flags
& TDF_DETAILS
)
2294 const char *funcname
2295 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2298 fprintf (file
, ";; Function %s\n\n", funcname
);
2299 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2300 n_basic_blocks
, n_edges
, last_basic_block
);
2302 brief_dump_cfg (file
);
2303 fprintf (file
, "\n");
2306 if (flags
& TDF_STATS
)
2307 dump_cfg_stats (file
);
2309 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2313 /* Dump CFG statistics on FILE. */
2316 dump_cfg_stats (FILE *file
)
2318 static long max_num_merged_labels
= 0;
2319 unsigned long size
, total
= 0;
2322 const char * const fmt_str
= "%-30s%-13s%12s\n";
2323 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2324 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2325 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2326 const char *funcname
2327 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2330 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2332 fprintf (file
, "---------------------------------------------------------\n");
2333 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2334 fprintf (file
, fmt_str
, "", " instances ", "used ");
2335 fprintf (file
, "---------------------------------------------------------\n");
2337 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2339 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2340 SCALE (size
), LABEL (size
));
2344 num_edges
+= EDGE_COUNT (bb
->succs
);
2345 size
= num_edges
* sizeof (struct edge_def
);
2347 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2349 fprintf (file
, "---------------------------------------------------------\n");
2350 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2352 fprintf (file
, "---------------------------------------------------------\n");
2353 fprintf (file
, "\n");
2355 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2356 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2358 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2359 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2361 fprintf (file
, "\n");
2365 /* Dump CFG statistics on stderr. Keep extern so that it's always
2366 linked in the final executable. */
2369 debug_cfg_stats (void)
2371 dump_cfg_stats (stderr
);
2375 /* Dump the flowgraph to a .vcg FILE. */
2378 tree_cfg2vcg (FILE *file
)
2383 const char *funcname
2384 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2386 /* Write the file header. */
2387 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2388 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2389 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2391 /* Write blocks and edges. */
2392 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2394 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2397 if (e
->flags
& EDGE_FAKE
)
2398 fprintf (file
, " linestyle: dotted priority: 10");
2400 fprintf (file
, " linestyle: solid priority: 100");
2402 fprintf (file
, " }\n");
2408 enum tree_code head_code
, end_code
;
2409 const char *head_name
, *end_name
;
2412 tree first
= first_stmt (bb
);
2413 tree last
= last_stmt (bb
);
2417 head_code
= TREE_CODE (first
);
2418 head_name
= tree_code_name
[head_code
];
2419 head_line
= get_lineno (first
);
2422 head_name
= "no-statement";
2426 end_code
= TREE_CODE (last
);
2427 end_name
= tree_code_name
[end_code
];
2428 end_line
= get_lineno (last
);
2431 end_name
= "no-statement";
2433 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2434 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2437 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2439 if (e
->dest
== EXIT_BLOCK_PTR
)
2440 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2442 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2444 if (e
->flags
& EDGE_FAKE
)
2445 fprintf (file
, " priority: 10 linestyle: dotted");
2447 fprintf (file
, " priority: 100 linestyle: solid");
2449 fprintf (file
, " }\n");
2452 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2456 fputs ("}\n\n", file
);
2461 /*---------------------------------------------------------------------------
2462 Miscellaneous helpers
2463 ---------------------------------------------------------------------------*/
2465 /* Return true if T represents a stmt that always transfers control. */
2468 is_ctrl_stmt (tree t
)
2470 return (TREE_CODE (t
) == COND_EXPR
2471 || TREE_CODE (t
) == SWITCH_EXPR
2472 || TREE_CODE (t
) == GOTO_EXPR
2473 || TREE_CODE (t
) == RETURN_EXPR
2474 || TREE_CODE (t
) == RESX_EXPR
);
2478 /* Return true if T is a statement that may alter the flow of control
2479 (e.g., a call to a non-returning function). */
2482 is_ctrl_altering_stmt (tree t
)
2487 call
= get_call_expr_in (t
);
2490 /* A non-pure/const CALL_EXPR alters flow control if the current
2491 function has nonlocal labels. */
2492 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2495 /* A CALL_EXPR also alters control flow if it does not return. */
2496 if (call_expr_flags (call
) & ECF_NORETURN
)
2500 /* OpenMP directives alter control flow. */
2501 if (OMP_DIRECTIVE_P (t
))
2504 /* If a statement can throw, it alters control flow. */
2505 return tree_can_throw_internal (t
);
2509 /* Return true if T is a computed goto. */
2512 computed_goto_p (tree t
)
2514 return (TREE_CODE (t
) == GOTO_EXPR
2515 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2519 /* Checks whether EXPR is a simple local goto. */
2522 simple_goto_p (tree expr
)
2524 return (TREE_CODE (expr
) == GOTO_EXPR
2525 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2529 /* Return true if T should start a new basic block. PREV_T is the
2530 statement preceding T. It is used when T is a label or a case label.
2531 Labels should only start a new basic block if their previous statement
2532 wasn't a label. Otherwise, sequence of labels would generate
2533 unnecessary basic blocks that only contain a single label. */
2536 stmt_starts_bb_p (tree t
, tree prev_t
)
2541 /* LABEL_EXPRs start a new basic block only if the preceding
2542 statement wasn't a label of the same type. This prevents the
2543 creation of consecutive blocks that have nothing but a single
2545 if (TREE_CODE (t
) == LABEL_EXPR
)
2547 /* Nonlocal and computed GOTO targets always start a new block. */
2548 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2549 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2552 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2554 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2557 cfg_stats
.num_merged_labels
++;
2568 /* Return true if T should end a basic block. */
2571 stmt_ends_bb_p (tree t
)
2573 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2577 /* Add gotos that used to be represented implicitly in the CFG. */
2580 disband_implicit_edges (void)
2583 block_stmt_iterator last
;
2590 last
= bsi_last (bb
);
2591 stmt
= last_stmt (bb
);
2593 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2595 /* Remove superfluous gotos from COND_EXPR branches. Moved
2596 from cfg_remove_useless_stmts here since it violates the
2597 invariants for tree--cfg correspondence and thus fits better
2598 here where we do it anyway. */
2599 e
= find_edge (bb
, bb
->next_bb
);
2602 if (e
->flags
& EDGE_TRUE_VALUE
)
2603 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2604 else if (e
->flags
& EDGE_FALSE_VALUE
)
2605 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2608 e
->flags
|= EDGE_FALLTHRU
;
2614 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2616 /* Remove the RETURN_EXPR if we may fall though to the exit
2618 gcc_assert (single_succ_p (bb
));
2619 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2621 if (bb
->next_bb
== EXIT_BLOCK_PTR
2622 && !TREE_OPERAND (stmt
, 0))
2624 bsi_remove (&last
, true);
2625 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2630 /* There can be no fallthru edge if the last statement is a control
2632 if (stmt
&& is_ctrl_stmt (stmt
))
2635 /* Find a fallthru edge and emit the goto if necessary. */
2636 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2637 if (e
->flags
& EDGE_FALLTHRU
)
2640 if (!e
|| e
->dest
== bb
->next_bb
)
2643 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2644 label
= tree_block_label (e
->dest
);
2646 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2647 #ifdef USE_MAPPED_LOCATION
2648 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2650 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2652 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2653 e
->flags
&= ~EDGE_FALLTHRU
;
2657 /* Remove block annotations and other datastructures. */
2660 delete_tree_cfg_annotations (void)
2662 label_to_block_map
= NULL
;
2666 /* Return the first statement in basic block BB. */
2669 first_stmt (basic_block bb
)
2671 block_stmt_iterator i
= bsi_start (bb
);
2672 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2676 /* Return the last statement in basic block BB. */
2679 last_stmt (basic_block bb
)
2681 block_stmt_iterator b
= bsi_last (bb
);
2682 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2686 /* Return a pointer to the last statement in block BB. */
2689 last_stmt_ptr (basic_block bb
)
2691 block_stmt_iterator last
= bsi_last (bb
);
2692 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2696 /* Return the last statement of an otherwise empty block. Return NULL
2697 if the block is totally empty, or if it contains more than one
2701 last_and_only_stmt (basic_block bb
)
2703 block_stmt_iterator i
= bsi_last (bb
);
2709 last
= bsi_stmt (i
);
2714 /* Empty statements should no longer appear in the instruction stream.
2715 Everything that might have appeared before should be deleted by
2716 remove_useless_stmts, and the optimizers should just bsi_remove
2717 instead of smashing with build_empty_stmt.
2719 Thus the only thing that should appear here in a block containing
2720 one executable statement is a label. */
2721 prev
= bsi_stmt (i
);
2722 if (TREE_CODE (prev
) == LABEL_EXPR
)
2729 /* Mark BB as the basic block holding statement T. */
2732 set_bb_for_stmt (tree t
, basic_block bb
)
2734 if (TREE_CODE (t
) == PHI_NODE
)
2736 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2738 tree_stmt_iterator i
;
2739 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2740 set_bb_for_stmt (tsi_stmt (i
), bb
);
2744 stmt_ann_t ann
= get_stmt_ann (t
);
2747 /* If the statement is a label, add the label to block-to-labels map
2748 so that we can speed up edge creation for GOTO_EXPRs. */
2749 if (TREE_CODE (t
) == LABEL_EXPR
)
2753 t
= LABEL_EXPR_LABEL (t
);
2754 uid
= LABEL_DECL_UID (t
);
2757 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2758 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2759 if (old_len
<= (unsigned) uid
)
2762 unsigned new_len
= 3 * uid
/ 2;
2764 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2766 addr
= VEC_address (basic_block
, label_to_block_map
);
2767 memset (&addr
[old_len
],
2768 0, sizeof (basic_block
) * (new_len
- old_len
));
2772 /* We're moving an existing label. Make sure that we've
2773 removed it from the old block. */
2775 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2776 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2781 /* Finds iterator for STMT. */
2783 extern block_stmt_iterator
2784 bsi_for_stmt (tree stmt
)
2786 block_stmt_iterator bsi
;
2788 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2789 if (bsi_stmt (bsi
) == stmt
)
2795 /* Mark statement T as modified, and update it. */
2797 update_modified_stmts (tree t
)
2799 if (TREE_CODE (t
) == STATEMENT_LIST
)
2801 tree_stmt_iterator i
;
2803 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2805 stmt
= tsi_stmt (i
);
2806 update_stmt_if_modified (stmt
);
2810 update_stmt_if_modified (t
);
2813 /* Insert statement (or statement list) T before the statement
2814 pointed-to by iterator I. M specifies how to update iterator I
2815 after insertion (see enum bsi_iterator_update). */
2818 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2820 set_bb_for_stmt (t
, i
->bb
);
2821 update_modified_stmts (t
);
2822 tsi_link_before (&i
->tsi
, t
, m
);
2826 /* Insert statement (or statement list) T after the statement
2827 pointed-to by iterator I. M specifies how to update iterator I
2828 after insertion (see enum bsi_iterator_update). */
2831 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2833 set_bb_for_stmt (t
, i
->bb
);
2834 update_modified_stmts (t
);
2835 tsi_link_after (&i
->tsi
, t
, m
);
2839 /* Remove the statement pointed to by iterator I. The iterator is updated
2840 to the next statement.
2842 When REMOVE_EH_INFO is true we remove the statement pointed to by
2843 iterator I from the EH tables. Otherwise we do not modify the EH
2846 Generally, REMOVE_EH_INFO should be true when the statement is going to
2847 be removed from the IL and not reinserted elsewhere. */
2850 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2852 tree t
= bsi_stmt (*i
);
2853 set_bb_for_stmt (t
, NULL
);
2854 delink_stmt_imm_use (t
);
2855 tsi_delink (&i
->tsi
);
2856 mark_stmt_modified (t
);
2858 remove_stmt_from_eh_region (t
);
2862 /* Move the statement at FROM so it comes right after the statement at TO. */
2865 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2867 tree stmt
= bsi_stmt (*from
);
2868 bsi_remove (from
, false);
2869 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2873 /* Move the statement at FROM so it comes right before the statement at TO. */
2876 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2878 tree stmt
= bsi_stmt (*from
);
2879 bsi_remove (from
, false);
2880 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2884 /* Move the statement at FROM to the end of basic block BB. */
2887 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2889 block_stmt_iterator last
= bsi_last (bb
);
2891 /* Have to check bsi_end_p because it could be an empty block. */
2892 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2893 bsi_move_before (from
, &last
);
2895 bsi_move_after (from
, &last
);
2899 /* Replace the contents of the statement pointed to by iterator BSI
2900 with STMT. If UPDATE_EH_INFO is true, the exception handling
2901 information of the original statement is moved to the new statement. */
2904 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2907 tree orig_stmt
= bsi_stmt (*bsi
);
2909 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2910 set_bb_for_stmt (stmt
, bsi
->bb
);
2912 /* Preserve EH region information from the original statement, if
2913 requested by the caller. */
2916 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2919 remove_stmt_from_eh_region (orig_stmt
);
2920 add_stmt_to_eh_region (stmt
, eh_region
);
2924 delink_stmt_imm_use (orig_stmt
);
2925 *bsi_stmt_ptr (*bsi
) = stmt
;
2926 mark_stmt_modified (stmt
);
2927 update_modified_stmts (stmt
);
2931 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2932 is made to place the statement in an existing basic block, but
2933 sometimes that isn't possible. When it isn't possible, the edge is
2934 split and the statement is added to the new block.
2936 In all cases, the returned *BSI points to the correct location. The
2937 return value is true if insertion should be done after the location,
2938 or false if it should be done before the location. If new basic block
2939 has to be created, it is stored in *NEW_BB. */
2942 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2943 basic_block
*new_bb
)
2945 basic_block dest
, src
;
2951 /* If the destination has one predecessor which has no PHI nodes,
2952 insert there. Except for the exit block.
2954 The requirement for no PHI nodes could be relaxed. Basically we
2955 would have to examine the PHIs to prove that none of them used
2956 the value set by the statement we want to insert on E. That
2957 hardly seems worth the effort. */
2958 if (single_pred_p (dest
)
2959 && ! phi_nodes (dest
)
2960 && dest
!= EXIT_BLOCK_PTR
)
2962 *bsi
= bsi_start (dest
);
2963 if (bsi_end_p (*bsi
))
2966 /* Make sure we insert after any leading labels. */
2967 tmp
= bsi_stmt (*bsi
);
2968 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2971 if (bsi_end_p (*bsi
))
2973 tmp
= bsi_stmt (*bsi
);
2976 if (bsi_end_p (*bsi
))
2978 *bsi
= bsi_last (dest
);
2985 /* If the source has one successor, the edge is not abnormal and
2986 the last statement does not end a basic block, insert there.
2987 Except for the entry block. */
2989 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2990 && single_succ_p (src
)
2991 && src
!= ENTRY_BLOCK_PTR
)
2993 *bsi
= bsi_last (src
);
2994 if (bsi_end_p (*bsi
))
2997 tmp
= bsi_stmt (*bsi
);
2998 if (!stmt_ends_bb_p (tmp
))
3001 /* Insert code just before returning the value. We may need to decompose
3002 the return in the case it contains non-trivial operand. */
3003 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3005 tree op
= TREE_OPERAND (tmp
, 0);
3006 if (op
&& !is_gimple_val (op
))
3008 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3009 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3010 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3017 /* Otherwise, create a new basic block, and split this edge. */
3018 dest
= split_edge (e
);
3021 e
= single_pred_edge (dest
);
3026 /* This routine will commit all pending edge insertions, creating any new
3027 basic blocks which are necessary. */
3030 bsi_commit_edge_inserts (void)
3036 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3039 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3040 bsi_commit_one_edge_insert (e
, NULL
);
3044 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3045 to this block, otherwise set it to NULL. */
3048 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3052 if (PENDING_STMT (e
))
3054 block_stmt_iterator bsi
;
3055 tree stmt
= PENDING_STMT (e
);
3057 PENDING_STMT (e
) = NULL_TREE
;
3059 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3060 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3062 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3067 /* Add STMT to the pending list of edge E. No actual insertion is
3068 made until a call to bsi_commit_edge_inserts () is made. */
3071 bsi_insert_on_edge (edge e
, tree stmt
)
3073 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3076 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3077 block has to be created, it is returned. */
3080 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3082 block_stmt_iterator bsi
;
3083 basic_block new_bb
= NULL
;
3085 gcc_assert (!PENDING_STMT (e
));
3087 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3088 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3090 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3095 /*---------------------------------------------------------------------------
3096 Tree specific functions for CFG manipulation
3097 ---------------------------------------------------------------------------*/
3099 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3102 reinstall_phi_args (edge new_edge
, edge old_edge
)
3106 if (!PENDING_STMT (old_edge
))
3109 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3111 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3113 tree result
= TREE_PURPOSE (var
);
3114 tree arg
= TREE_VALUE (var
);
3116 gcc_assert (result
== PHI_RESULT (phi
));
3118 add_phi_arg (phi
, arg
, new_edge
);
3121 PENDING_STMT (old_edge
) = NULL
;
3124 /* Returns the basic block after that the new basic block created
3125 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3126 near its "logical" location. This is of most help to humans looking
3127 at debugging dumps. */
3130 split_edge_bb_loc (edge edge_in
)
3132 basic_block dest
= edge_in
->dest
;
3134 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3135 return edge_in
->src
;
3137 return dest
->prev_bb
;
3140 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3141 Abort on abnormal edges. */
3144 tree_split_edge (edge edge_in
)
3146 basic_block new_bb
, after_bb
, dest
;
3149 /* Abnormal edges cannot be split. */
3150 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3152 dest
= edge_in
->dest
;
3154 after_bb
= split_edge_bb_loc (edge_in
);
3156 new_bb
= create_empty_bb (after_bb
);
3157 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3158 new_bb
->count
= edge_in
->count
;
3159 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3160 new_edge
->probability
= REG_BR_PROB_BASE
;
3161 new_edge
->count
= edge_in
->count
;
3163 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3165 reinstall_phi_args (new_edge
, e
);
3171 /* Return true when BB has label LABEL in it. */
3174 has_label_p (basic_block bb
, tree label
)
3176 block_stmt_iterator bsi
;
3178 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3180 tree stmt
= bsi_stmt (bsi
);
3182 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3184 if (LABEL_EXPR_LABEL (stmt
) == label
)
3191 /* Callback for walk_tree, check that all elements with address taken are
3192 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3193 inside a PHI node. */
3196 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3199 bool in_phi
= (data
!= NULL
);
3204 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3205 #define CHECK_OP(N, MSG) \
3206 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3207 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3209 switch (TREE_CODE (t
))
3212 if (SSA_NAME_IN_FREE_LIST (t
))
3214 error ("SSA name in freelist but still referenced");
3220 x
= fold (ASSERT_EXPR_COND (t
));
3221 if (x
== boolean_false_node
)
3223 error ("ASSERT_EXPR with an always-false condition");
3229 x
= TREE_OPERAND (t
, 0);
3230 if (TREE_CODE (x
) == BIT_FIELD_REF
3231 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3233 error ("GIMPLE register modified with BIT_FIELD_REF");
3242 bool old_side_effects
;
3245 bool new_side_effects
;
3247 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3248 dead PHIs that take the address of something. But if the PHI
3249 result is dead, the fact that it takes the address of anything
3250 is irrelevant. Because we can not tell from here if a PHI result
3251 is dead, we just skip this check for PHIs altogether. This means
3252 we may be missing "valid" checks, but what can you do?
3253 This was PR19217. */
3257 old_invariant
= TREE_INVARIANT (t
);
3258 old_constant
= TREE_CONSTANT (t
);
3259 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3261 recompute_tree_invariant_for_addr_expr (t
);
3262 new_invariant
= TREE_INVARIANT (t
);
3263 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3264 new_constant
= TREE_CONSTANT (t
);
3266 if (old_invariant
!= new_invariant
)
3268 error ("invariant not recomputed when ADDR_EXPR changed");
3272 if (old_constant
!= new_constant
)
3274 error ("constant not recomputed when ADDR_EXPR changed");
3277 if (old_side_effects
!= new_side_effects
)
3279 error ("side effects not recomputed when ADDR_EXPR changed");
3283 /* Skip any references (they will be checked when we recurse down the
3284 tree) and ensure that any variable used as a prefix is marked
3286 for (x
= TREE_OPERAND (t
, 0);
3287 handled_component_p (x
);
3288 x
= TREE_OPERAND (x
, 0))
3291 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3293 if (!TREE_ADDRESSABLE (x
))
3295 error ("address taken, but ADDRESSABLE bit not set");
3302 x
= COND_EXPR_COND (t
);
3303 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3305 error ("non-boolean used in condition");
3308 if (!is_gimple_condexpr (x
))
3310 error ("invalid conditional operand");
3317 case FIX_TRUNC_EXPR
:
3319 case FIX_FLOOR_EXPR
:
3320 case FIX_ROUND_EXPR
:
3325 case NON_LVALUE_EXPR
:
3326 case TRUTH_NOT_EXPR
:
3327 CHECK_OP (0, "invalid operand to unary operator");
3334 case ARRAY_RANGE_REF
:
3336 case VIEW_CONVERT_EXPR
:
3337 /* We have a nest of references. Verify that each of the operands
3338 that determine where to reference is either a constant or a variable,
3339 verify that the base is valid, and then show we've already checked
3341 while (handled_component_p (t
))
3343 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3344 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3345 else if (TREE_CODE (t
) == ARRAY_REF
3346 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3348 CHECK_OP (1, "invalid array index");
3349 if (TREE_OPERAND (t
, 2))
3350 CHECK_OP (2, "invalid array lower bound");
3351 if (TREE_OPERAND (t
, 3))
3352 CHECK_OP (3, "invalid array stride");
3354 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3356 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3357 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3360 t
= TREE_OPERAND (t
, 0);
3363 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3365 error ("invalid reference prefix");
3377 case UNORDERED_EXPR
:
3388 case TRUNC_DIV_EXPR
:
3390 case FLOOR_DIV_EXPR
:
3391 case ROUND_DIV_EXPR
:
3392 case TRUNC_MOD_EXPR
:
3394 case FLOOR_MOD_EXPR
:
3395 case ROUND_MOD_EXPR
:
3397 case EXACT_DIV_EXPR
:
3407 CHECK_OP (0, "invalid operand to binary operator");
3408 CHECK_OP (1, "invalid operand to binary operator");
3420 /* Verify STMT, return true if STMT is not in GIMPLE form.
3421 TODO: Implement type checking. */
3424 verify_stmt (tree stmt
, bool last_in_block
)
3428 if (OMP_DIRECTIVE_P (stmt
))
3430 /* OpenMP directives are validated by the FE and never operated
3431 on by the optimizers. Furthermore, OMP_FOR may contain
3432 non-gimple expressions when the main index variable has had
3433 its address taken. This does not affect the loop itself
3434 because the header of an OMP_FOR is merely used to determine
3435 how to setup the parallel iteration. */
3439 if (!is_gimple_stmt (stmt
))
3441 error ("is not a valid GIMPLE statement");
3445 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3448 debug_generic_stmt (addr
);
3452 /* If the statement is marked as part of an EH region, then it is
3453 expected that the statement could throw. Verify that when we
3454 have optimizations that simplify statements such that we prove
3455 that they cannot throw, that we update other data structures
3457 if (lookup_stmt_eh_region (stmt
) >= 0)
3459 if (!tree_could_throw_p (stmt
))
3461 error ("statement marked for throw, but doesn%'t");
3464 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3466 error ("statement marked for throw in middle of block");
3474 debug_generic_stmt (stmt
);
3479 /* Return true when the T can be shared. */
3482 tree_node_can_be_shared (tree t
)
3484 if (IS_TYPE_OR_DECL_P (t
)
3485 || is_gimple_min_invariant (t
)
3486 || TREE_CODE (t
) == SSA_NAME
3487 || t
== error_mark_node
3488 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3491 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3494 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3495 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3496 || TREE_CODE (t
) == COMPONENT_REF
3497 || TREE_CODE (t
) == REALPART_EXPR
3498 || TREE_CODE (t
) == IMAGPART_EXPR
)
3499 t
= TREE_OPERAND (t
, 0);
3508 /* Called via walk_trees. Verify tree sharing. */
3511 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3513 htab_t htab
= (htab_t
) data
;
3516 if (tree_node_can_be_shared (*tp
))
3518 *walk_subtrees
= false;
3522 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3524 return (tree
) *slot
;
3531 /* Verify the GIMPLE statement chain. */
3537 block_stmt_iterator bsi
;
3542 timevar_push (TV_TREE_STMT_VERIFY
);
3543 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3550 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3552 int phi_num_args
= PHI_NUM_ARGS (phi
);
3554 if (bb_for_stmt (phi
) != bb
)
3556 error ("bb_for_stmt (phi) is set to a wrong basic block");
3560 for (i
= 0; i
< phi_num_args
; i
++)
3562 tree t
= PHI_ARG_DEF (phi
, i
);
3565 /* Addressable variables do have SSA_NAMEs but they
3566 are not considered gimple values. */
3567 if (TREE_CODE (t
) != SSA_NAME
3568 && TREE_CODE (t
) != FUNCTION_DECL
3569 && !is_gimple_val (t
))
3571 error ("PHI def is not a GIMPLE value");
3572 debug_generic_stmt (phi
);
3573 debug_generic_stmt (t
);
3577 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3580 debug_generic_stmt (addr
);
3584 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3587 error ("incorrect sharing of tree nodes");
3588 debug_generic_stmt (phi
);
3589 debug_generic_stmt (addr
);
3595 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3597 tree stmt
= bsi_stmt (bsi
);
3599 if (bb_for_stmt (stmt
) != bb
)
3601 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3606 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3607 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3610 error ("incorrect sharing of tree nodes");
3611 debug_generic_stmt (stmt
);
3612 debug_generic_stmt (addr
);
3619 internal_error ("verify_stmts failed");
3622 timevar_pop (TV_TREE_STMT_VERIFY
);
3626 /* Verifies that the flow information is OK. */
3629 tree_verify_flow_info (void)
3633 block_stmt_iterator bsi
;
3638 if (ENTRY_BLOCK_PTR
->stmt_list
)
3640 error ("ENTRY_BLOCK has a statement list associated with it");
3644 if (EXIT_BLOCK_PTR
->stmt_list
)
3646 error ("EXIT_BLOCK has a statement list associated with it");
3650 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3651 if (e
->flags
& EDGE_FALLTHRU
)
3653 error ("fallthru to exit from bb %d", e
->src
->index
);
3659 bool found_ctrl_stmt
= false;
3663 /* Skip labels on the start of basic block. */
3664 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3666 tree prev_stmt
= stmt
;
3668 stmt
= bsi_stmt (bsi
);
3670 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3673 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3675 error ("nonlocal label ");
3676 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3677 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3682 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3685 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3686 fprintf (stderr
, " to block does not match in bb %d",
3691 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3692 != current_function_decl
)
3695 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3696 fprintf (stderr
, " has incorrect context in bb %d",
3702 /* Verify that body of basic block BB is free of control flow. */
3703 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3705 tree stmt
= bsi_stmt (bsi
);
3707 if (found_ctrl_stmt
)
3709 error ("control flow in the middle of basic block %d",
3714 if (stmt_ends_bb_p (stmt
))
3715 found_ctrl_stmt
= true;
3717 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3720 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3721 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3726 bsi
= bsi_last (bb
);
3727 if (bsi_end_p (bsi
))
3730 stmt
= bsi_stmt (bsi
);
3732 err
|= verify_eh_edges (stmt
);
3734 if (is_ctrl_stmt (stmt
))
3736 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3737 if (e
->flags
& EDGE_FALLTHRU
)
3739 error ("fallthru edge after a control statement in bb %d",
3745 switch (TREE_CODE (stmt
))
3751 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3752 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3754 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3758 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3760 if (!true_edge
|| !false_edge
3761 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3762 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3763 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3764 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3765 || EDGE_COUNT (bb
->succs
) >= 3)
3767 error ("wrong outgoing edge flags at end of bb %d",
3772 if (!has_label_p (true_edge
->dest
,
3773 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3775 error ("%<then%> label does not match edge at end of bb %d",
3780 if (!has_label_p (false_edge
->dest
,
3781 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3783 error ("%<else%> label does not match edge at end of bb %d",
3791 if (simple_goto_p (stmt
))
3793 error ("explicit goto at end of bb %d", bb
->index
);
3798 /* FIXME. We should double check that the labels in the
3799 destination blocks have their address taken. */
3800 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3801 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3802 | EDGE_FALSE_VALUE
))
3803 || !(e
->flags
& EDGE_ABNORMAL
))
3805 error ("wrong outgoing edge flags at end of bb %d",
3813 if (!single_succ_p (bb
)
3814 || (single_succ_edge (bb
)->flags
3815 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3816 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3818 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3821 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3823 error ("return edge does not point to exit in bb %d",
3836 vec
= SWITCH_LABELS (stmt
);
3837 n
= TREE_VEC_LENGTH (vec
);
3839 /* Mark all the destination basic blocks. */
3840 for (i
= 0; i
< n
; ++i
)
3842 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3843 basic_block label_bb
= label_to_block (lab
);
3845 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3846 label_bb
->aux
= (void *)1;
3849 /* Verify that the case labels are sorted. */
3850 prev
= TREE_VEC_ELT (vec
, 0);
3851 for (i
= 1; i
< n
- 1; ++i
)
3853 tree c
= TREE_VEC_ELT (vec
, i
);
3856 error ("found default case not at end of case vector");
3860 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3862 error ("case labels not sorted: ");
3863 print_generic_expr (stderr
, prev
, 0);
3864 fprintf (stderr
," is greater than ");
3865 print_generic_expr (stderr
, c
, 0);
3866 fprintf (stderr
," but comes before it.\n");
3871 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3873 error ("no default case found at end of case vector");
3877 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3881 error ("extra outgoing edge %d->%d",
3882 bb
->index
, e
->dest
->index
);
3885 e
->dest
->aux
= (void *)2;
3886 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3887 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3889 error ("wrong outgoing edge flags at end of bb %d",
3895 /* Check that we have all of them. */
3896 for (i
= 0; i
< n
; ++i
)
3898 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3899 basic_block label_bb
= label_to_block (lab
);
3901 if (label_bb
->aux
!= (void *)2)
3903 error ("missing edge %i->%i",
3904 bb
->index
, label_bb
->index
);
3909 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3910 e
->dest
->aux
= (void *)0;
3917 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3918 verify_dominators (CDI_DOMINATORS
);
3924 /* Updates phi nodes after creating a forwarder block joined
3925 by edge FALLTHRU. */
3928 tree_make_forwarder_block (edge fallthru
)
3932 basic_block dummy
, bb
;
3933 tree phi
, new_phi
, var
;
3935 dummy
= fallthru
->src
;
3936 bb
= fallthru
->dest
;
3938 if (single_pred_p (bb
))
3941 /* If we redirected a branch we must create new phi nodes at the
3943 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3945 var
= PHI_RESULT (phi
);
3946 new_phi
= create_phi_node (var
, bb
);
3947 SSA_NAME_DEF_STMT (var
) = new_phi
;
3948 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3949 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3952 /* Ensure that the PHI node chain is in the same order. */
3953 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3955 /* Add the arguments we have stored on edges. */
3956 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3961 flush_pending_stmts (e
);
3966 /* Return a non-special label in the head of basic block BLOCK.
3967 Create one if it doesn't exist. */
3970 tree_block_label (basic_block bb
)
3972 block_stmt_iterator i
, s
= bsi_start (bb
);
3976 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3978 stmt
= bsi_stmt (i
);
3979 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3981 label
= LABEL_EXPR_LABEL (stmt
);
3982 if (!DECL_NONLOCAL (label
))
3985 bsi_move_before (&i
, &s
);
3990 label
= create_artificial_label ();
3991 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3992 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3997 /* Attempt to perform edge redirection by replacing a possibly complex
3998 jump instruction by a goto or by removing the jump completely.
3999 This can apply only if all edges now point to the same block. The
4000 parameters and return values are equivalent to
4001 redirect_edge_and_branch. */
4004 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4006 basic_block src
= e
->src
;
4007 block_stmt_iterator b
;
4010 /* We can replace or remove a complex jump only when we have exactly
4012 if (EDGE_COUNT (src
->succs
) != 2
4013 /* Verify that all targets will be TARGET. Specifically, the
4014 edge that is not E must also go to TARGET. */
4015 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4021 stmt
= bsi_stmt (b
);
4023 if (TREE_CODE (stmt
) == COND_EXPR
4024 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4026 bsi_remove (&b
, true);
4027 e
= ssa_redirect_edge (e
, target
);
4028 e
->flags
= EDGE_FALLTHRU
;
4036 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4037 edge representing the redirected branch. */
4040 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4042 basic_block bb
= e
->src
;
4043 block_stmt_iterator bsi
;
4047 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4050 if (e
->src
!= ENTRY_BLOCK_PTR
4051 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4054 if (e
->dest
== dest
)
4057 label
= tree_block_label (dest
);
4059 bsi
= bsi_last (bb
);
4060 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4062 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4065 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4066 ? COND_EXPR_THEN (stmt
)
4067 : COND_EXPR_ELSE (stmt
));
4068 GOTO_DESTINATION (stmt
) = label
;
4072 /* No non-abnormal edges should lead from a non-simple goto, and
4073 simple ones should be represented implicitly. */
4078 tree cases
= get_cases_for_edge (e
, stmt
);
4080 /* If we have a list of cases associated with E, then use it
4081 as it's a lot faster than walking the entire case vector. */
4084 edge e2
= find_edge (e
->src
, dest
);
4091 CASE_LABEL (cases
) = label
;
4092 cases
= TREE_CHAIN (cases
);
4095 /* If there was already an edge in the CFG, then we need
4096 to move all the cases associated with E to E2. */
4099 tree cases2
= get_cases_for_edge (e2
, stmt
);
4101 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4102 TREE_CHAIN (cases2
) = first
;
4107 tree vec
= SWITCH_LABELS (stmt
);
4108 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4110 for (i
= 0; i
< n
; i
++)
4112 tree elt
= TREE_VEC_ELT (vec
, i
);
4114 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4115 CASE_LABEL (elt
) = label
;
4123 bsi_remove (&bsi
, true);
4124 e
->flags
|= EDGE_FALLTHRU
;
4128 /* Otherwise it must be a fallthru edge, and we don't need to
4129 do anything besides redirecting it. */
4130 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4134 /* Update/insert PHI nodes as necessary. */
4136 /* Now update the edges in the CFG. */
4137 e
= ssa_redirect_edge (e
, dest
);
4143 /* Simple wrapper, as we can always redirect fallthru edges. */
4146 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4148 e
= tree_redirect_edge_and_branch (e
, dest
);
4155 /* Splits basic block BB after statement STMT (but at least after the
4156 labels). If STMT is NULL, BB is split just after the labels. */
4159 tree_split_block (basic_block bb
, void *stmt
)
4161 block_stmt_iterator bsi
, bsi_tgt
;
4167 new_bb
= create_empty_bb (bb
);
4169 /* Redirect the outgoing edges. */
4170 new_bb
->succs
= bb
->succs
;
4172 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4175 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4178 /* Move everything from BSI to the new basic block. */
4179 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4181 act
= bsi_stmt (bsi
);
4182 if (TREE_CODE (act
) == LABEL_EXPR
)
4195 bsi_tgt
= bsi_start (new_bb
);
4196 while (!bsi_end_p (bsi
))
4198 act
= bsi_stmt (bsi
);
4199 bsi_remove (&bsi
, false);
4200 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4207 /* Moves basic block BB after block AFTER. */
4210 tree_move_block_after (basic_block bb
, basic_block after
)
4212 if (bb
->prev_bb
== after
)
4216 link_block (bb
, after
);
4222 /* Return true if basic_block can be duplicated. */
4225 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4231 /* Create a duplicate of the basic block BB. NOTE: This does not
4232 preserve SSA form. */
4235 tree_duplicate_bb (basic_block bb
)
4238 block_stmt_iterator bsi
, bsi_tgt
;
4241 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4243 /* Copy the PHI nodes. We ignore PHI node arguments here because
4244 the incoming edges have not been setup yet. */
4245 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4247 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4248 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4251 /* Keep the chain of PHI nodes in the same order so that they can be
4252 updated by ssa_redirect_edge. */
4253 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4255 bsi_tgt
= bsi_start (new_bb
);
4256 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4258 def_operand_p def_p
;
4259 ssa_op_iter op_iter
;
4263 stmt
= bsi_stmt (bsi
);
4264 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4267 /* Create a new copy of STMT and duplicate STMT's virtual
4269 copy
= unshare_expr (stmt
);
4270 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4271 copy_virtual_operands (copy
, stmt
);
4272 region
= lookup_stmt_eh_region (stmt
);
4274 add_stmt_to_eh_region (copy
, region
);
4276 /* Create new names for all the definitions created by COPY and
4277 add replacement mappings for each new name. */
4278 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4279 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4286 /* Basic block BB_COPY was created by code duplication. Add phi node
4287 arguments for edges going out of BB_COPY. The blocks that were
4288 duplicated have BB_DUPLICATED set. */
4291 add_phi_args_after_copy_bb (basic_block bb_copy
)
4293 basic_block bb
, dest
;
4296 tree phi
, phi_copy
, phi_next
, def
;
4298 bb
= get_bb_original (bb_copy
);
4300 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4302 if (!phi_nodes (e_copy
->dest
))
4305 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4306 dest
= get_bb_original (e_copy
->dest
);
4308 dest
= e_copy
->dest
;
4310 e
= find_edge (bb
, dest
);
4313 /* During loop unrolling the target of the latch edge is copied.
4314 In this case we are not looking for edge to dest, but to
4315 duplicated block whose original was dest. */
4316 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4317 if ((e
->dest
->flags
& BB_DUPLICATED
)
4318 && get_bb_original (e
->dest
) == dest
)
4321 gcc_assert (e
!= NULL
);
4324 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4326 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4328 phi_next
= PHI_CHAIN (phi
);
4329 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4330 add_phi_arg (phi_copy
, def
, e_copy
);
4335 /* Blocks in REGION_COPY array of length N_REGION were created by
4336 duplication of basic blocks. Add phi node arguments for edges
4337 going from these blocks. */
4340 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4344 for (i
= 0; i
< n_region
; i
++)
4345 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4347 for (i
= 0; i
< n_region
; i
++)
4348 add_phi_args_after_copy_bb (region_copy
[i
]);
4350 for (i
= 0; i
< n_region
; i
++)
4351 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4354 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4355 important exit edge EXIT. By important we mean that no SSA name defined
4356 inside region is live over the other exit edges of the region. All entry
4357 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4358 to the duplicate of the region. SSA form, dominance and loop information
4359 is updated. The new basic blocks are stored to REGION_COPY in the same
4360 order as they had in REGION, provided that REGION_COPY is not NULL.
4361 The function returns false if it is unable to copy the region,
4365 tree_duplicate_sese_region (edge entry
, edge exit
,
4366 basic_block
*region
, unsigned n_region
,
4367 basic_block
*region_copy
)
4370 bool free_region_copy
= false, copying_header
= false;
4371 struct loop
*loop
= entry
->dest
->loop_father
;
4375 int total_freq
= 0, entry_freq
= 0;
4376 gcov_type total_count
= 0, entry_count
= 0;
4378 if (!can_copy_bbs_p (region
, n_region
))
4381 /* Some sanity checking. Note that we do not check for all possible
4382 missuses of the functions. I.e. if you ask to copy something weird,
4383 it will work, but the state of structures probably will not be
4385 for (i
= 0; i
< n_region
; i
++)
4387 /* We do not handle subloops, i.e. all the blocks must belong to the
4389 if (region
[i
]->loop_father
!= loop
)
4392 if (region
[i
] != entry
->dest
4393 && region
[i
] == loop
->header
)
4399 /* In case the function is used for loop header copying (which is the primary
4400 use), ensure that EXIT and its copy will be new latch and entry edges. */
4401 if (loop
->header
== entry
->dest
)
4403 copying_header
= true;
4404 loop
->copy
= loop
->outer
;
4406 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4409 for (i
= 0; i
< n_region
; i
++)
4410 if (region
[i
] != exit
->src
4411 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4417 region_copy
= XNEWVEC (basic_block
, n_region
);
4418 free_region_copy
= true;
4421 gcc_assert (!need_ssa_update_p ());
4423 /* Record blocks outside the region that are dominated by something
4425 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4426 initialize_original_copy_tables ();
4428 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4430 if (entry
->dest
->count
)
4432 total_count
= entry
->dest
->count
;
4433 entry_count
= entry
->count
;
4434 /* Fix up corner cases, to avoid division by zero or creation of negative
4436 if (entry_count
> total_count
)
4437 entry_count
= total_count
;
4441 total_freq
= entry
->dest
->frequency
;
4442 entry_freq
= EDGE_FREQUENCY (entry
);
4443 /* Fix up corner cases, to avoid division by zero or creation of negative
4445 if (total_freq
== 0)
4447 else if (entry_freq
> total_freq
)
4448 entry_freq
= total_freq
;
4451 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4452 split_edge_bb_loc (entry
));
4455 scale_bbs_frequencies_gcov_type (region
, n_region
,
4456 total_count
- entry_count
,
4458 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4463 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4465 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4470 loop
->header
= exit
->dest
;
4471 loop
->latch
= exit
->src
;
4474 /* Redirect the entry and add the phi node arguments. */
4475 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4476 gcc_assert (redirected
!= NULL
);
4477 flush_pending_stmts (entry
);
4479 /* Concerning updating of dominators: We must recount dominators
4480 for entry block and its copy. Anything that is outside of the
4481 region, but was dominated by something inside needs recounting as
4483 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4484 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4485 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4488 /* Add the other PHI node arguments. */
4489 add_phi_args_after_copy (region_copy
, n_region
);
4491 /* Update the SSA web. */
4492 update_ssa (TODO_update_ssa
);
4494 if (free_region_copy
)
4497 free_original_copy_tables ();
4502 DEF_VEC_P(basic_block);
4503 DEF_VEC_ALLOC_P(basic_block,heap);
4506 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4507 adding blocks when the dominator traversal reaches EXIT. This
4508 function silently assumes that ENTRY strictly dominates EXIT. */
4511 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4512 VEC(basic_block
,heap
) **bbs_p
)
4516 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4518 son
= next_dom_son (CDI_DOMINATORS
, son
))
4520 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4522 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4532 bitmap vars_to_remove
;
4533 htab_t new_label_map
;
4537 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4538 contained in *TP and change the DECL_CONTEXT of every local
4539 variable referenced in *TP. */
4542 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4544 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4547 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t
))))
4548 TREE_BLOCK (t
) = p
->block
;
4550 if (OMP_DIRECTIVE_P (t
)
4551 && TREE_CODE (t
) != OMP_RETURN
4552 && TREE_CODE (t
) != OMP_CONTINUE
)
4554 /* Do not remap variables inside OMP directives. Variables
4555 referenced in clauses and directive header belong to the
4556 parent function and should not be moved into the child
4558 bool save_remap_decls_p
= p
->remap_decls_p
;
4559 p
->remap_decls_p
= false;
4562 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4564 p
->remap_decls_p
= save_remap_decls_p
;
4566 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4568 if (TREE_CODE (t
) == LABEL_DECL
)
4570 if (p
->new_label_map
)
4572 struct tree_map in
, *out
;
4574 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4579 DECL_CONTEXT (t
) = p
->to_context
;
4581 else if (p
->remap_decls_p
)
4583 DECL_CONTEXT (t
) = p
->to_context
;
4585 if (TREE_CODE (t
) == VAR_DECL
)
4587 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4588 f
->unexpanded_var_list
4589 = tree_cons (0, t
, f
->unexpanded_var_list
);
4591 /* Mark T to be removed from the original function,
4592 otherwise it will be given a DECL_RTL when the
4593 original function is expanded. */
4594 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4598 else if (TYPE_P (t
))
4605 /* Move basic block BB from function CFUN to function DEST_FN. The
4606 block is moved out of the original linked list and placed after
4607 block AFTER in the new list. Also, the block is removed from the
4608 original array of blocks and placed in DEST_FN's array of blocks.
4609 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4610 updated to reflect the moved edges.
4612 On exit, local variables that need to be removed from
4613 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4616 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4617 basic_block after
, bool update_edge_count_p
,
4618 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4620 struct control_flow_graph
*cfg
;
4623 block_stmt_iterator si
;
4624 struct move_stmt_d d
;
4625 unsigned old_len
, new_len
;
4628 /* Link BB to the new linked list. */
4629 move_block_after (bb
, after
);
4631 /* Update the edge count in the corresponding flowgraphs. */
4632 if (update_edge_count_p
)
4633 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4635 cfun
->cfg
->x_n_edges
--;
4636 dest_cfun
->cfg
->x_n_edges
++;
4639 /* Remove BB from the original basic block array. */
4640 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4641 cfun
->cfg
->x_n_basic_blocks
--;
4643 /* Grow DEST_CFUN's basic block array if needed. */
4644 cfg
= dest_cfun
->cfg
;
4645 cfg
->x_n_basic_blocks
++;
4646 if (bb
->index
> cfg
->x_last_basic_block
)
4647 cfg
->x_last_basic_block
= bb
->index
;
4649 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4650 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4652 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4653 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4654 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4655 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4658 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4659 cfg
->x_last_basic_block
, bb
);
4661 /* The statements in BB need to be associated with a new TREE_BLOCK.
4662 Labels need to be associated with a new label-to-block map. */
4663 memset (&d
, 0, sizeof (d
));
4664 d
.vars_to_remove
= vars_to_remove
;
4666 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4668 tree stmt
= bsi_stmt (si
);
4671 d
.from_context
= cfun
->decl
;
4672 d
.to_context
= dest_cfun
->decl
;
4673 d
.remap_decls_p
= true;
4674 d
.new_label_map
= new_label_map
;
4675 if (TREE_BLOCK (stmt
))
4676 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4678 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4680 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4682 tree label
= LABEL_EXPR_LABEL (stmt
);
4683 int uid
= LABEL_DECL_UID (label
);
4685 gcc_assert (uid
> -1);
4687 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4688 if (old_len
<= (unsigned) uid
)
4690 new_len
= 3 * uid
/ 2;
4691 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4693 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4694 memset (&addr
[old_len
], 0,
4695 sizeof (basic_block
) * (new_len
- old_len
));
4698 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4699 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4701 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4703 if (uid
>= dest_cfun
->last_label_uid
)
4704 dest_cfun
->last_label_uid
= uid
+ 1;
4706 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4707 TREE_OPERAND (stmt
, 0) =
4708 build_int_cst (NULL_TREE
,
4709 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4712 region
= lookup_stmt_eh_region (stmt
);
4715 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4716 remove_stmt_from_eh_region (stmt
);
4721 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4722 the outermost EH region. Use REGION as the incoming base EH region. */
4725 find_outermost_region_in_block (struct function
*src_cfun
,
4726 basic_block bb
, int region
)
4728 block_stmt_iterator si
;
4730 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4732 tree stmt
= bsi_stmt (si
);
4735 if (TREE_CODE (stmt
) == RESX_EXPR
)
4736 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4738 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4739 if (stmt_region
> 0)
4742 region
= stmt_region
;
4743 else if (stmt_region
!= region
)
4745 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4746 gcc_assert (region
!= -1);
4755 new_label_mapper (tree decl
, void *data
)
4757 htab_t hash
= (htab_t
) data
;
4761 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4763 m
= xmalloc (sizeof (struct tree_map
));
4764 m
->hash
= DECL_UID (decl
);
4766 m
->to
= create_artificial_label ();
4767 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4769 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4770 gcc_assert (*slot
== NULL
);
4777 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4778 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4779 single basic block in the original CFG and the new basic block is
4780 returned. DEST_CFUN must not have a CFG yet.
4782 Note that the region need not be a pure SESE region. Blocks inside
4783 the region may contain calls to abort/exit. The only restriction
4784 is that ENTRY_BB should be the only entry point and it must
4787 All local variables referenced in the region are assumed to be in
4788 the corresponding BLOCK_VARS and unexpanded variable lists
4789 associated with DEST_CFUN. */
4792 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4793 basic_block exit_bb
)
4795 VEC(basic_block
,heap
) *bbs
;
4796 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4797 struct function
*saved_cfun
;
4798 int *entry_flag
, *exit_flag
, eh_offset
;
4799 unsigned i
, num_entry_edges
, num_exit_edges
;
4802 bitmap vars_to_remove
;
4803 htab_t new_label_map
;
4807 /* Collect all the blocks in the region. Manually add ENTRY_BB
4808 because it won't be added by dfs_enumerate_from. */
4809 calculate_dominance_info (CDI_DOMINATORS
);
4811 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4813 gcc_assert (entry_bb
!= exit_bb
4815 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4818 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4819 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4821 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4822 the predecessor edges to ENTRY_BB and the successor edges to
4823 EXIT_BB so that we can re-attach them to the new basic block that
4824 will replace the region. */
4825 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4826 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4827 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4829 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4831 entry_flag
[i
] = e
->flags
;
4832 entry_pred
[i
++] = e
->src
;
4838 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4839 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4840 sizeof (basic_block
));
4841 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4843 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4845 exit_flag
[i
] = e
->flags
;
4846 exit_succ
[i
++] = e
->dest
;
4857 /* Switch context to the child function to initialize DEST_FN's CFG. */
4858 gcc_assert (dest_cfun
->cfg
== NULL
);
4861 init_empty_tree_cfg ();
4863 /* Initialize EH information for the new function. */
4865 new_label_map
= NULL
;
4870 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4871 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4873 init_eh_for_function ();
4876 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4877 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4878 new_label_map
, region
, 0);
4884 /* Move blocks from BBS into DEST_CFUN. */
4885 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4886 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4887 vars_to_remove
= BITMAP_ALLOC (NULL
);
4888 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4890 /* No need to update edge counts on the last block. It has
4891 already been updated earlier when we detached the region from
4892 the original CFG. */
4893 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4894 new_label_map
, eh_offset
);
4899 htab_delete (new_label_map
);
4901 /* Remove the variables marked in VARS_TO_REMOVE from
4902 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4903 DECL_RTL in the context of CFUN. */
4904 if (!bitmap_empty_p (vars_to_remove
))
4908 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4910 tree var
= TREE_VALUE (*p
);
4911 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4913 *p
= TREE_CHAIN (*p
);
4917 p
= &TREE_CHAIN (*p
);
4921 BITMAP_FREE (vars_to_remove
);
4923 /* Rewire the entry and exit blocks. The successor to the entry
4924 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4925 the child function. Similarly, the predecessor of DEST_FN's
4926 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4927 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4928 various CFG manipulation function get to the right CFG.
4930 FIXME, this is silly. The CFG ought to become a parameter to
4933 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4935 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4938 /* Back in the original function, the SESE region has disappeared,
4939 create a new basic block in its place. */
4940 bb
= create_empty_bb (entry_pred
[0]);
4941 for (i
= 0; i
< num_entry_edges
; i
++)
4942 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4944 for (i
= 0; i
< num_exit_edges
; i
++)
4945 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4954 free_dominance_info (CDI_DOMINATORS
);
4955 free_dominance_info (CDI_POST_DOMINATORS
);
4956 VEC_free (basic_block
, heap
, bbs
);
4962 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4965 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4967 tree arg
, vars
, var
;
4968 bool ignore_topmost_bind
= false, any_var
= false;
4971 struct function
*saved_cfun
;
4973 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4975 arg
= DECL_ARGUMENTS (fn
);
4978 print_generic_expr (file
, arg
, dump_flags
);
4979 if (TREE_CHAIN (arg
))
4980 fprintf (file
, ", ");
4981 arg
= TREE_CHAIN (arg
);
4983 fprintf (file
, ")\n");
4985 if (flags
& TDF_DETAILS
)
4986 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4987 if (flags
& TDF_RAW
)
4989 dump_node (fn
, TDF_SLIM
| flags
, file
);
4993 /* Switch CFUN to point to FN. */
4995 cfun
= DECL_STRUCT_FUNCTION (fn
);
4997 /* When GIMPLE is lowered, the variables are no longer available in
4998 BIND_EXPRs, so display them separately. */
4999 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5001 ignore_topmost_bind
= true;
5003 fprintf (file
, "{\n");
5004 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5006 var
= TREE_VALUE (vars
);
5008 print_generic_decl (file
, var
, flags
);
5009 fprintf (file
, "\n");
5015 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5017 /* Make a CFG based dump. */
5018 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5019 if (!ignore_topmost_bind
)
5020 fprintf (file
, "{\n");
5022 if (any_var
&& n_basic_blocks
)
5023 fprintf (file
, "\n");
5026 dump_generic_bb (file
, bb
, 2, flags
);
5028 fprintf (file
, "}\n");
5029 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5035 /* Make a tree based dump. */
5036 chain
= DECL_SAVED_TREE (fn
);
5038 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5040 if (ignore_topmost_bind
)
5042 chain
= BIND_EXPR_BODY (chain
);
5050 if (!ignore_topmost_bind
)
5051 fprintf (file
, "{\n");
5056 fprintf (file
, "\n");
5058 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5059 if (ignore_topmost_bind
)
5060 fprintf (file
, "}\n");
5063 fprintf (file
, "\n\n");
5070 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5073 debug_function (tree fn
, int flags
)
5075 dump_function_to_file (fn
, stderr
, flags
);
5079 /* Pretty print of the loops intermediate representation. */
5080 static void print_loop (FILE *, struct loop
*, int);
5081 static void print_pred_bbs (FILE *, basic_block bb
);
5082 static void print_succ_bbs (FILE *, basic_block bb
);
5085 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5088 print_pred_bbs (FILE *file
, basic_block bb
)
5093 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5094 fprintf (file
, "bb_%d ", e
->src
->index
);
5098 /* Print on FILE the indexes for the successors of basic_block BB. */
5101 print_succ_bbs (FILE *file
, basic_block bb
)
5106 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5107 fprintf (file
, "bb_%d ", e
->dest
->index
);
5111 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5114 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5122 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5123 memset ((void *) s_indent
, ' ', (size_t) indent
);
5124 s_indent
[indent
] = '\0';
5126 /* Print the loop's header. */
5127 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5129 /* Print the loop's body. */
5130 fprintf (file
, "%s{\n", s_indent
);
5132 if (bb
->loop_father
== loop
)
5134 /* Print the basic_block's header. */
5135 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5136 print_pred_bbs (file
, bb
);
5137 fprintf (file
, "}, succs = {");
5138 print_succ_bbs (file
, bb
);
5139 fprintf (file
, "})\n");
5141 /* Print the basic_block's body. */
5142 fprintf (file
, "%s {\n", s_indent
);
5143 tree_dump_bb (bb
, file
, indent
+ 4);
5144 fprintf (file
, "%s }\n", s_indent
);
5147 print_loop (file
, loop
->inner
, indent
+ 2);
5148 fprintf (file
, "%s}\n", s_indent
);
5149 print_loop (file
, loop
->next
, indent
);
5153 /* Follow a CFG edge from the entry point of the program, and on entry
5154 of a loop, pretty print the loop structure on FILE. */
5157 print_loop_ir (FILE *file
)
5161 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5162 if (bb
&& bb
->loop_father
)
5163 print_loop (file
, bb
->loop_father
, 0);
5167 /* Debugging loops structure at tree level. */
5170 debug_loop_ir (void)
5172 print_loop_ir (stderr
);
5176 /* Return true if BB ends with a call, possibly followed by some
5177 instructions that must stay with the call. Return false,
5181 tree_block_ends_with_call_p (basic_block bb
)
5183 block_stmt_iterator bsi
= bsi_last (bb
);
5184 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5188 /* Return true if BB ends with a conditional branch. Return false,
5192 tree_block_ends_with_condjump_p (basic_block bb
)
5194 tree stmt
= last_stmt (bb
);
5195 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5199 /* Return true if we need to add fake edge to exit at statement T.
5200 Helper function for tree_flow_call_edges_add. */
5203 need_fake_edge_p (tree t
)
5207 /* NORETURN and LONGJMP calls already have an edge to exit.
5208 CONST and PURE calls do not need one.
5209 We don't currently check for CONST and PURE here, although
5210 it would be a good idea, because those attributes are
5211 figured out from the RTL in mark_constant_function, and
5212 the counter incrementation code from -fprofile-arcs
5213 leads to different results from -fbranch-probabilities. */
5214 call
= get_call_expr_in (t
);
5216 && !(call_expr_flags (call
) & ECF_NORETURN
))
5219 if (TREE_CODE (t
) == ASM_EXPR
5220 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5227 /* Add fake edges to the function exit for any non constant and non
5228 noreturn calls, volatile inline assembly in the bitmap of blocks
5229 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5230 the number of blocks that were split.
5232 The goal is to expose cases in which entering a basic block does
5233 not imply that all subsequent instructions must be executed. */
5236 tree_flow_call_edges_add (sbitmap blocks
)
5239 int blocks_split
= 0;
5240 int last_bb
= last_basic_block
;
5241 bool check_last_block
= false;
5243 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5247 check_last_block
= true;
5249 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5251 /* In the last basic block, before epilogue generation, there will be
5252 a fallthru edge to EXIT. Special care is required if the last insn
5253 of the last basic block is a call because make_edge folds duplicate
5254 edges, which would result in the fallthru edge also being marked
5255 fake, which would result in the fallthru edge being removed by
5256 remove_fake_edges, which would result in an invalid CFG.
5258 Moreover, we can't elide the outgoing fake edge, since the block
5259 profiler needs to take this into account in order to solve the minimal
5260 spanning tree in the case that the call doesn't return.
5262 Handle this by adding a dummy instruction in a new last basic block. */
5263 if (check_last_block
)
5265 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5266 block_stmt_iterator bsi
= bsi_last (bb
);
5268 if (!bsi_end_p (bsi
))
5271 if (t
&& need_fake_edge_p (t
))
5275 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5278 bsi_insert_on_edge (e
, build_empty_stmt ());
5279 bsi_commit_edge_inserts ();
5284 /* Now add fake edges to the function exit for any non constant
5285 calls since there is no way that we can determine if they will
5287 for (i
= 0; i
< last_bb
; i
++)
5289 basic_block bb
= BASIC_BLOCK (i
);
5290 block_stmt_iterator bsi
;
5291 tree stmt
, last_stmt
;
5296 if (blocks
&& !TEST_BIT (blocks
, i
))
5299 bsi
= bsi_last (bb
);
5300 if (!bsi_end_p (bsi
))
5302 last_stmt
= bsi_stmt (bsi
);
5305 stmt
= bsi_stmt (bsi
);
5306 if (need_fake_edge_p (stmt
))
5309 /* The handling above of the final block before the
5310 epilogue should be enough to verify that there is
5311 no edge to the exit block in CFG already.
5312 Calling make_edge in such case would cause us to
5313 mark that edge as fake and remove it later. */
5314 #ifdef ENABLE_CHECKING
5315 if (stmt
== last_stmt
)
5317 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5318 gcc_assert (e
== NULL
);
5322 /* Note that the following may create a new basic block
5323 and renumber the existing basic blocks. */
5324 if (stmt
!= last_stmt
)
5326 e
= split_block (bb
, stmt
);
5330 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5334 while (!bsi_end_p (bsi
));
5339 verify_flow_info ();
5341 return blocks_split
;
5345 tree_purge_dead_eh_edges (basic_block bb
)
5347 bool changed
= false;
5350 tree stmt
= last_stmt (bb
);
5352 if (stmt
&& tree_can_throw_internal (stmt
))
5355 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5357 if (e
->flags
& EDGE_EH
)
5366 /* Removal of dead EH edges might change dominators of not
5367 just immediate successors. E.g. when bb1 is changed so that
5368 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5369 eh edges purged by this function in:
5381 idom(bb5) must be recomputed. For now just free the dominance
5384 free_dominance_info (CDI_DOMINATORS
);
5390 tree_purge_all_dead_eh_edges (bitmap blocks
)
5392 bool changed
= false;
5396 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5398 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5404 /* This function is called whenever a new edge is created or
5408 tree_execute_on_growing_pred (edge e
)
5410 basic_block bb
= e
->dest
;
5413 reserve_phi_args_for_new_edge (bb
);
5416 /* This function is called immediately before edge E is removed from
5417 the edge vector E->dest->preds. */
5420 tree_execute_on_shrinking_pred (edge e
)
5422 if (phi_nodes (e
->dest
))
5423 remove_phi_args (e
);
5426 /*---------------------------------------------------------------------------
5427 Helper functions for Loop versioning
5428 ---------------------------------------------------------------------------*/
5430 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5431 of 'first'. Both of them are dominated by 'new_head' basic block. When
5432 'new_head' was created by 'second's incoming edge it received phi arguments
5433 on the edge by split_edge(). Later, additional edge 'e' was created to
5434 connect 'new_head' and 'first'. Now this routine adds phi args on this
5435 additional edge 'e' that new_head to second edge received as part of edge
5440 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5441 basic_block new_head
, edge e
)
5444 edge e2
= find_edge (new_head
, second
);
5446 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5447 edge, we should always have an edge from NEW_HEAD to SECOND. */
5448 gcc_assert (e2
!= NULL
);
5450 /* Browse all 'second' basic block phi nodes and add phi args to
5451 edge 'e' for 'first' head. PHI args are always in correct order. */
5453 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5455 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5457 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5458 add_phi_arg (phi1
, def
, e
);
5462 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5463 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5464 the destination of the ELSE part. */
5466 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5467 basic_block cond_bb
, void *cond_e
)
5469 block_stmt_iterator bsi
;
5470 tree goto1
= NULL_TREE
;
5471 tree goto2
= NULL_TREE
;
5472 tree new_cond_expr
= NULL_TREE
;
5473 tree cond_expr
= (tree
) cond_e
;
5476 /* Build new conditional expr */
5477 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5478 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5479 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5481 /* Add new cond in cond_bb. */
5482 bsi
= bsi_start (cond_bb
);
5483 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5484 /* Adjust edges appropriately to connect new head with first head
5485 as well as second head. */
5486 e0
= single_succ_edge (cond_bb
);
5487 e0
->flags
&= ~EDGE_FALLTHRU
;
5488 e0
->flags
|= EDGE_FALSE_VALUE
;
5491 struct cfg_hooks tree_cfg_hooks
= {
5493 tree_verify_flow_info
,
5494 tree_dump_bb
, /* dump_bb */
5495 create_bb
, /* create_basic_block */
5496 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5497 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5498 remove_bb
, /* delete_basic_block */
5499 tree_split_block
, /* split_block */
5500 tree_move_block_after
, /* move_block_after */
5501 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5502 tree_merge_blocks
, /* merge_blocks */
5503 tree_predict_edge
, /* predict_edge */
5504 tree_predicted_by_p
, /* predicted_by_p */
5505 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5506 tree_duplicate_bb
, /* duplicate_block */
5507 tree_split_edge
, /* split_edge */
5508 tree_make_forwarder_block
, /* make_forward_block */
5509 NULL
, /* tidy_fallthru_edge */
5510 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5511 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5512 tree_flow_call_edges_add
, /* flow_call_edges_add */
5513 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5514 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5515 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5516 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5517 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5518 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5519 flush_pending_stmts
/* flush_pending_stmts */
5523 /* Split all critical edges. */
5526 split_critical_edges (void)
5532 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5533 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5534 mappings around the calls to split_edge. */
5535 start_recording_case_labels ();
5538 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5539 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5544 end_recording_case_labels ();
5548 struct tree_opt_pass pass_split_crit_edges
=
5550 "crited", /* name */
5552 split_critical_edges
, /* execute */
5555 0, /* static_pass_number */
5556 TV_TREE_SPLIT_EDGES
, /* tv_id */
5557 PROP_cfg
, /* properties required */
5558 PROP_no_crit_edges
, /* properties_provided */
5559 0, /* properties_destroyed */
5560 0, /* todo_flags_start */
5561 TODO_dump_func
, /* todo_flags_finish */
5566 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5567 a temporary, make sure and register it to be renamed if necessary,
5568 and finally return the temporary. Put the statements to compute
5569 EXP before the current statement in BSI. */
5572 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5574 tree t
, new_stmt
, orig_stmt
;
5576 if (is_gimple_val (exp
))
5579 t
= make_rename_temp (type
, NULL
);
5580 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5582 orig_stmt
= bsi_stmt (*bsi
);
5583 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5584 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5586 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5591 /* Build a ternary operation and gimplify it. Emit code before BSI.
5592 Return the gimple_val holding the result. */
5595 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5596 tree type
, tree a
, tree b
, tree c
)
5600 ret
= fold_build3 (code
, type
, a
, b
, c
);
5603 return gimplify_val (bsi
, type
, ret
);
5606 /* Build a binary operation and gimplify it. Emit code before BSI.
5607 Return the gimple_val holding the result. */
5610 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5611 tree type
, tree a
, tree b
)
5615 ret
= fold_build2 (code
, type
, a
, b
);
5618 return gimplify_val (bsi
, type
, ret
);
5621 /* Build a unary operation and gimplify it. Emit code before BSI.
5622 Return the gimple_val holding the result. */
5625 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5630 ret
= fold_build1 (code
, type
, a
);
5633 return gimplify_val (bsi
, type
, ret
);
5638 /* Emit return warnings. */
5641 execute_warn_function_return (void)
5643 #ifdef USE_MAPPED_LOCATION
5644 source_location location
;
5652 /* If we have a path to EXIT, then we do return. */
5653 if (TREE_THIS_VOLATILE (cfun
->decl
)
5654 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5656 #ifdef USE_MAPPED_LOCATION
5657 location
= UNKNOWN_LOCATION
;
5661 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5663 last
= last_stmt (e
->src
);
5664 if (TREE_CODE (last
) == RETURN_EXPR
5665 #ifdef USE_MAPPED_LOCATION
5666 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5668 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5672 #ifdef USE_MAPPED_LOCATION
5673 if (location
== UNKNOWN_LOCATION
)
5674 location
= cfun
->function_end_locus
;
5675 warning (0, "%H%<noreturn%> function does return", &location
);
5678 locus
= &cfun
->function_end_locus
;
5679 warning (0, "%H%<noreturn%> function does return", locus
);
5683 /* If we see "return;" in some basic block, then we do reach the end
5684 without returning a value. */
5685 else if (warn_return_type
5686 && !TREE_NO_WARNING (cfun
->decl
)
5687 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5688 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5690 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5692 tree last
= last_stmt (e
->src
);
5693 if (TREE_CODE (last
) == RETURN_EXPR
5694 && TREE_OPERAND (last
, 0) == NULL
5695 && !TREE_NO_WARNING (last
))
5697 #ifdef USE_MAPPED_LOCATION
5698 location
= EXPR_LOCATION (last
);
5699 if (location
== UNKNOWN_LOCATION
)
5700 location
= cfun
->function_end_locus
;
5701 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5703 locus
= EXPR_LOCUS (last
);
5705 locus
= &cfun
->function_end_locus
;
5706 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5708 TREE_NO_WARNING (cfun
->decl
) = 1;
5717 /* Given a basic block B which ends with a conditional and has
5718 precisely two successors, determine which of the edges is taken if
5719 the conditional is true and which is taken if the conditional is
5720 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5723 extract_true_false_edges_from_block (basic_block b
,
5727 edge e
= EDGE_SUCC (b
, 0);
5729 if (e
->flags
& EDGE_TRUE_VALUE
)
5732 *false_edge
= EDGE_SUCC (b
, 1);
5737 *true_edge
= EDGE_SUCC (b
, 1);
5741 struct tree_opt_pass pass_warn_function_return
=
5745 execute_warn_function_return
, /* execute */
5748 0, /* static_pass_number */
5750 PROP_cfg
, /* properties_required */
5751 0, /* properties_provided */
5752 0, /* properties_destroyed */
5753 0, /* todo_flags_start */
5754 0, /* todo_flags_finish */
5758 /* Emit noreturn warnings. */
5761 execute_warn_function_noreturn (void)
5763 if (warn_missing_noreturn
5764 && !TREE_THIS_VOLATILE (cfun
->decl
)
5765 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5766 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5767 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5768 "for attribute %<noreturn%>",
5773 struct tree_opt_pass pass_warn_function_noreturn
=
5777 execute_warn_function_noreturn
, /* execute */
5780 0, /* static_pass_number */
5782 PROP_cfg
, /* properties_required */
5783 0, /* properties_provided */
5784 0, /* properties_destroyed */
5785 0, /* todo_flags_start */
5786 0, /* todo_flags_finish */