1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
48 #include "tree-ssa-propagate.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity
= 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 struct edge_to_cases_elt
73 /* The edge itself. Necessary for hashing and equality tests. */
76 /* The case labels associated with this edge. We link these up via
77 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
78 when we destroy the hash table. This prevents problems when copying
83 static htab_t edge_to_cases
;
88 long num_merged_labels
;
91 static struct cfg_stats_d cfg_stats
;
93 /* Nonzero if we found a computed goto while building basic blocks. */
94 static bool found_computed_goto
;
96 /* Basic blocks and flowgraphs. */
97 static basic_block
create_bb (void *, void *, basic_block
);
98 static void make_blocks (tree
);
99 static void factor_computed_gotos (void);
102 static void make_edges (void);
103 static void make_cond_expr_edges (basic_block
);
104 static void make_switch_expr_edges (basic_block
);
105 static void make_goto_expr_edges (basic_block
);
106 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
107 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
108 static unsigned int split_critical_edges (void);
110 /* Various helpers. */
111 static inline bool stmt_starts_bb_p (tree
, tree
);
112 static int tree_verify_flow_info (void);
113 static void tree_make_forwarder_block (edge
);
114 static void tree_cfg2vcg (FILE *);
115 static inline void change_bb_for_stmt (tree t
, basic_block bb
);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block
, basic_block
);
119 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
120 static void remove_bb (basic_block
);
121 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
122 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
123 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
124 static tree
find_case_label_for_value (tree
, tree
);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status
= PROFILE_ABSENT
;
132 n_basic_blocks
= NUM_FIXED_BLOCKS
;
133 last_basic_block
= NUM_FIXED_BLOCKS
;
134 basic_block_info
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
135 VEC_safe_grow (basic_block
, gc
, basic_block_info
, initial_cfg_capacity
);
136 memset (VEC_address (basic_block
, basic_block_info
), 0,
137 sizeof (basic_block
) * initial_cfg_capacity
);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
141 VEC_safe_grow (basic_block
, gc
, label_to_block_map
, initial_cfg_capacity
);
142 memset (VEC_address (basic_block
, label_to_block_map
),
143 0, sizeof (basic_block
) * initial_cfg_capacity
);
145 SET_BASIC_BLOCK (ENTRY_BLOCK
, ENTRY_BLOCK_PTR
);
146 SET_BASIC_BLOCK (EXIT_BLOCK
, EXIT_BLOCK_PTR
);
147 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
148 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
151 /*---------------------------------------------------------------------------
153 ---------------------------------------------------------------------------*/
155 /* Entry point to the CFG builder for trees. TP points to the list of
156 statements to be added to the flowgraph. */
159 build_tree_cfg (tree
*tp
)
161 /* Register specific tree functions. */
162 tree_register_cfg_hooks ();
164 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
166 init_empty_tree_cfg ();
168 found_computed_goto
= 0;
171 /* Computed gotos are hell to deal with, especially if there are
172 lots of them with a large number of destinations. So we factor
173 them to a common computed goto location before we build the
174 edge list. After we convert back to normal form, we will un-factor
175 the computed gotos since factoring introduces an unwanted jump. */
176 if (found_computed_goto
)
177 factor_computed_gotos ();
179 /* Make sure there is always at least one block, even if it's empty. */
180 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
181 create_empty_bb (ENTRY_BLOCK_PTR
);
183 /* Adjust the size of the array. */
184 if (VEC_length (basic_block
, basic_block_info
) < (size_t) n_basic_blocks
)
186 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
188 VEC_safe_grow (basic_block
, gc
, basic_block_info
, n_basic_blocks
);
189 p
= VEC_address (basic_block
, basic_block_info
);
190 memset (&p
[old_size
], 0,
191 sizeof (basic_block
) * (n_basic_blocks
- old_size
));
194 /* To speed up statement iterator walks, we first purge dead labels. */
195 cleanup_dead_labels ();
197 /* Group case nodes to reduce the number of edges.
198 We do this after cleaning up dead labels because otherwise we miss
199 a lot of obvious case merging opportunities. */
200 group_case_labels ();
202 /* Create the edges of the flowgraph. */
205 /* Debugging dumps. */
207 /* Write the flowgraph to a VCG file. */
209 int local_dump_flags
;
210 FILE *vcg_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
213 tree_cfg2vcg (vcg_file
);
214 dump_end (TDI_vcg
, vcg_file
);
218 #ifdef ENABLE_CHECKING
222 /* Dump a textual representation of the flowgraph. */
224 dump_tree_cfg (dump_file
, dump_flags
);
228 execute_build_cfg (void)
230 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
234 struct tree_opt_pass pass_build_cfg
=
238 execute_build_cfg
, /* execute */
241 0, /* static_pass_number */
242 TV_TREE_CFG
, /* tv_id */
243 PROP_gimple_leh
, /* properties_required */
244 PROP_cfg
, /* properties_provided */
245 0, /* properties_destroyed */
246 0, /* todo_flags_start */
247 TODO_verify_stmts
, /* todo_flags_finish */
251 /* Search the CFG for any computed gotos. If found, factor them to a
252 common computed goto site. Also record the location of that site so
253 that we can un-factor the gotos after we have converted back to
257 factor_computed_gotos (void)
260 tree factored_label_decl
= NULL
;
262 tree factored_computed_goto_label
= NULL
;
263 tree factored_computed_goto
= NULL
;
265 /* We know there are one or more computed gotos in this function.
266 Examine the last statement in each basic block to see if the block
267 ends with a computed goto. */
271 block_stmt_iterator bsi
= bsi_last (bb
);
276 last
= bsi_stmt (bsi
);
278 /* Ignore the computed goto we create when we factor the original
280 if (last
== factored_computed_goto
)
283 /* If the last statement is a computed goto, factor it. */
284 if (computed_goto_p (last
))
288 /* The first time we find a computed goto we need to create
289 the factored goto block and the variable each original
290 computed goto will use for their goto destination. */
291 if (! factored_computed_goto
)
293 basic_block new_bb
= create_empty_bb (bb
);
294 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
296 /* Create the destination of the factored goto. Each original
297 computed goto will put its desired destination into this
298 variable and jump to the label we create immediately
300 var
= create_tmp_var (ptr_type_node
, "gotovar");
302 /* Build a label for the new block which will contain the
303 factored computed goto. */
304 factored_label_decl
= create_artificial_label ();
305 factored_computed_goto_label
306 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
307 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
310 /* Build our new computed goto. */
311 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
312 bsi_insert_after (&new_bsi
, factored_computed_goto
,
316 /* Copy the original computed goto's destination into VAR. */
317 assignment
= build2 (MODIFY_EXPR
, ptr_type_node
,
318 var
, GOTO_DESTINATION (last
));
319 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
321 /* And re-vector the computed goto to the new destination. */
322 GOTO_DESTINATION (last
) = factored_label_decl
;
328 /* Build a flowgraph for the statement_list STMT_LIST. */
331 make_blocks (tree stmt_list
)
333 tree_stmt_iterator i
= tsi_start (stmt_list
);
335 bool start_new_block
= true;
336 bool first_stmt_of_list
= true;
337 basic_block bb
= ENTRY_BLOCK_PTR
;
339 while (!tsi_end_p (i
))
346 /* If the statement starts a new basic block or if we have determined
347 in a previous pass that we need to create a new block for STMT, do
349 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
351 if (!first_stmt_of_list
)
352 stmt_list
= tsi_split_statement_list_before (&i
);
353 bb
= create_basic_block (stmt_list
, NULL
, bb
);
354 start_new_block
= false;
357 /* Now add STMT to BB and create the subgraphs for special statement
359 set_bb_for_stmt (stmt
, bb
);
361 if (computed_goto_p (stmt
))
362 found_computed_goto
= true;
364 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
366 if (stmt_ends_bb_p (stmt
))
367 start_new_block
= true;
370 first_stmt_of_list
= false;
375 /* Create and return a new empty basic block after bb AFTER. */
378 create_bb (void *h
, void *e
, basic_block after
)
384 /* Create and initialize a new basic block. Since alloc_block uses
385 ggc_alloc_cleared to allocate a basic block, we do not have to
386 clear the newly allocated basic block here. */
389 bb
->index
= last_basic_block
;
391 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
393 /* Add the new block to the linked list of blocks. */
394 link_block (bb
, after
);
396 /* Grow the basic block array if needed. */
397 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
399 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
400 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
402 VEC_safe_grow (basic_block
, gc
, basic_block_info
, new_size
);
403 p
= VEC_address (basic_block
, basic_block_info
);
404 memset (&p
[old_size
], 0, sizeof (basic_block
) * (new_size
- old_size
));
407 /* Add the newly created block to the array. */
408 SET_BASIC_BLOCK (last_basic_block
, bb
);
417 /*---------------------------------------------------------------------------
419 ---------------------------------------------------------------------------*/
421 /* Fold COND_EXPR_COND of each COND_EXPR. */
424 fold_cond_expr_cond (void)
430 tree stmt
= last_stmt (bb
);
433 && TREE_CODE (stmt
) == COND_EXPR
)
435 tree cond
= fold (COND_EXPR_COND (stmt
));
436 if (integer_zerop (cond
))
437 COND_EXPR_COND (stmt
) = boolean_false_node
;
438 else if (integer_onep (cond
))
439 COND_EXPR_COND (stmt
) = boolean_true_node
;
444 /* Join all the blocks in the flowgraph. */
450 struct omp_region
*cur_region
= NULL
;
452 /* Create an edge from entry to the first block with executable
454 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
456 /* Traverse the basic block array placing edges. */
459 tree last
= last_stmt (bb
);
464 enum tree_code code
= TREE_CODE (last
);
468 make_goto_expr_edges (bb
);
472 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
476 make_cond_expr_edges (bb
);
480 make_switch_expr_edges (bb
);
484 make_eh_edges (last
);
489 /* If this function receives a nonlocal goto, then we need to
490 make edges from this call site to all the nonlocal goto
492 if (tree_can_make_abnormal_goto (last
))
493 make_abnormal_goto_edges (bb
, true);
495 /* If this statement has reachable exception handlers, then
496 create abnormal edges to them. */
497 make_eh_edges (last
);
499 /* Some calls are known not to return. */
500 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
504 if (is_ctrl_altering_stmt (last
))
506 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
507 CALL_EXPR may have an abnormal edge. Search the RHS for
508 this case and create any required edges. */
509 if (tree_can_make_abnormal_goto (last
))
510 make_abnormal_goto_edges (bb
, true);
512 make_eh_edges (last
);
524 cur_region
= new_omp_region (bb
, code
, cur_region
);
529 cur_region
= new_omp_region (bb
, code
, cur_region
);
534 /* In the case of an OMP_SECTION, the edge will go somewhere
535 other than the next block. This will be created later. */
536 cur_region
->exit
= bb
;
537 fallthru
= cur_region
->type
!= OMP_SECTION
;
538 cur_region
= cur_region
->outer
;
542 cur_region
->cont
= bb
;
543 switch (cur_region
->type
)
546 /* ??? Technically there should be a some sort of loopback
547 edge here, but it goes to a block that doesn't exist yet,
548 and without it, updating the ssa form would be a real
549 bear. Fortunately, we don't yet do ssa before expanding
554 /* Wire up the edges into and out of the nested sections. */
555 /* ??? Similarly wrt loopback. */
557 struct omp_region
*i
;
558 for (i
= cur_region
->inner
; i
; i
= i
->next
)
560 gcc_assert (i
->type
== OMP_SECTION
);
561 make_edge (cur_region
->entry
, i
->entry
, 0);
562 make_edge (i
->exit
, bb
, EDGE_FALLTHRU
);
574 gcc_assert (!stmt_ends_bb_p (last
));
582 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
588 /* Fold COND_EXPR_COND of each COND_EXPR. */
589 fold_cond_expr_cond ();
591 /* Clean up the graph and warn for unreachable code. */
596 /* Create the edges for a COND_EXPR starting at block BB.
597 At this point, both clauses must contain only simple gotos. */
600 make_cond_expr_edges (basic_block bb
)
602 tree entry
= last_stmt (bb
);
603 basic_block then_bb
, else_bb
;
604 tree then_label
, else_label
;
608 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
610 /* Entry basic blocks for each component. */
611 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
612 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
613 then_bb
= label_to_block (then_label
);
614 else_bb
= label_to_block (else_label
);
616 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
617 #ifdef USE_MAPPED_LOCATION
618 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
620 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
622 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
625 #ifdef USE_MAPPED_LOCATION
626 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
628 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
633 /* Hashing routine for EDGE_TO_CASES. */
636 edge_to_cases_hash (const void *p
)
638 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
640 /* Hash on the edge itself (which is a pointer). */
641 return htab_hash_pointer (e
);
644 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
645 for equality is just a pointer comparison. */
648 edge_to_cases_eq (const void *p1
, const void *p2
)
650 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
651 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
656 /* Called for each element in the hash table (P) as we delete the
657 edge to cases hash table.
659 Clear all the TREE_CHAINs to prevent problems with copying of
660 SWITCH_EXPRs and structure sharing rules, then free the hash table
664 edge_to_cases_cleanup (void *p
)
666 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
669 for (t
= elt
->case_labels
; t
; t
= next
)
671 next
= TREE_CHAIN (t
);
672 TREE_CHAIN (t
) = NULL
;
677 /* Start recording information mapping edges to case labels. */
680 start_recording_case_labels (void)
682 gcc_assert (edge_to_cases
== NULL
);
684 edge_to_cases
= htab_create (37,
687 edge_to_cases_cleanup
);
690 /* Return nonzero if we are recording information for case labels. */
693 recording_case_labels_p (void)
695 return (edge_to_cases
!= NULL
);
698 /* Stop recording information mapping edges to case labels and
699 remove any information we have recorded. */
701 end_recording_case_labels (void)
703 htab_delete (edge_to_cases
);
704 edge_to_cases
= NULL
;
707 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
710 record_switch_edge (edge e
, tree case_label
)
712 struct edge_to_cases_elt
*elt
;
715 /* Build a hash table element so we can see if E is already
717 elt
= XNEW (struct edge_to_cases_elt
);
719 elt
->case_labels
= case_label
;
721 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
725 /* E was not in the hash table. Install E into the hash table. */
730 /* E was already in the hash table. Free ELT as we do not need it
734 /* Get the entry stored in the hash table. */
735 elt
= (struct edge_to_cases_elt
*) *slot
;
737 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
738 TREE_CHAIN (case_label
) = elt
->case_labels
;
739 elt
->case_labels
= case_label
;
743 /* If we are inside a {start,end}_recording_cases block, then return
744 a chain of CASE_LABEL_EXPRs from T which reference E.
746 Otherwise return NULL. */
749 get_cases_for_edge (edge e
, tree t
)
751 struct edge_to_cases_elt elt
, *elt_p
;
756 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
757 chains available. Return NULL so the caller can detect this case. */
758 if (!recording_case_labels_p ())
763 elt
.case_labels
= NULL
;
764 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
768 elt_p
= (struct edge_to_cases_elt
*)*slot
;
769 return elt_p
->case_labels
;
772 /* If we did not find E in the hash table, then this must be the first
773 time we have been queried for information about E & T. Add all the
774 elements from T to the hash table then perform the query again. */
776 vec
= SWITCH_LABELS (t
);
777 n
= TREE_VEC_LENGTH (vec
);
778 for (i
= 0; i
< n
; i
++)
780 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
781 basic_block label_bb
= label_to_block (lab
);
782 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
787 /* Create the edges for a SWITCH_EXPR starting at block BB.
788 At this point, the switch body has been lowered and the
789 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
792 make_switch_expr_edges (basic_block bb
)
794 tree entry
= last_stmt (bb
);
798 vec
= SWITCH_LABELS (entry
);
799 n
= TREE_VEC_LENGTH (vec
);
801 for (i
= 0; i
< n
; ++i
)
803 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
804 basic_block label_bb
= label_to_block (lab
);
805 make_edge (bb
, label_bb
, 0);
810 /* Return the basic block holding label DEST. */
813 label_to_block_fn (struct function
*ifun
, tree dest
)
815 int uid
= LABEL_DECL_UID (dest
);
817 /* We would die hard when faced by an undefined label. Emit a label to
818 the very first basic block. This will hopefully make even the dataflow
819 and undefined variable warnings quite right. */
820 if ((errorcount
|| sorrycount
) && uid
< 0)
822 block_stmt_iterator bsi
=
823 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
826 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
827 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
828 uid
= LABEL_DECL_UID (dest
);
830 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
831 <= (unsigned int) uid
)
833 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
836 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
837 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
840 make_abnormal_goto_edges (basic_block bb
, bool for_call
)
842 basic_block target_bb
;
843 block_stmt_iterator bsi
;
845 FOR_EACH_BB (target_bb
)
846 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
848 tree target
= bsi_stmt (bsi
);
850 if (TREE_CODE (target
) != LABEL_EXPR
)
853 target
= LABEL_EXPR_LABEL (target
);
855 /* Make an edge to every label block that has been marked as a
856 potential target for a computed goto or a non-local goto. */
857 if ((FORCED_LABEL (target
) && !for_call
)
858 || (DECL_NONLOCAL (target
) && for_call
))
860 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
866 /* Create edges for a goto statement at block BB. */
869 make_goto_expr_edges (basic_block bb
)
871 block_stmt_iterator last
= bsi_last (bb
);
872 tree goto_t
= bsi_stmt (last
);
874 /* A simple GOTO creates normal edges. */
875 if (simple_goto_p (goto_t
))
877 tree dest
= GOTO_DESTINATION (goto_t
);
878 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
879 #ifdef USE_MAPPED_LOCATION
880 e
->goto_locus
= EXPR_LOCATION (goto_t
);
882 e
->goto_locus
= EXPR_LOCUS (goto_t
);
884 bsi_remove (&last
, true);
888 /* A computed GOTO creates abnormal edges. */
889 make_abnormal_goto_edges (bb
, false);
893 /*---------------------------------------------------------------------------
895 ---------------------------------------------------------------------------*/
897 /* Cleanup useless labels in basic blocks. This is something we wish
898 to do early because it allows us to group case labels before creating
899 the edges for the CFG, and it speeds up block statement iterators in
901 We only run this pass once, running it more than once is probably not
904 /* A map from basic block index to the leading label of that block. */
905 static tree
*label_for_bb
;
907 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
909 update_eh_label (struct eh_region
*region
)
911 tree old_label
= get_eh_region_tree_label (region
);
915 basic_block bb
= label_to_block (old_label
);
917 /* ??? After optimizing, there may be EH regions with labels
918 that have already been removed from the function body, so
919 there is no basic block for them. */
923 new_label
= label_for_bb
[bb
->index
];
924 set_eh_region_tree_label (region
, new_label
);
928 /* Given LABEL return the first label in the same basic block. */
930 main_block_label (tree label
)
932 basic_block bb
= label_to_block (label
);
934 /* label_to_block possibly inserted undefined label into the chain. */
935 if (!label_for_bb
[bb
->index
])
936 label_for_bb
[bb
->index
] = label
;
937 return label_for_bb
[bb
->index
];
940 /* Cleanup redundant labels. This is a three-step process:
941 1) Find the leading label for each block.
942 2) Redirect all references to labels to the leading labels.
943 3) Cleanup all useless labels. */
946 cleanup_dead_labels (void)
949 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
951 /* Find a suitable label for each block. We use the first user-defined
952 label if there is one, or otherwise just the first label we see. */
955 block_stmt_iterator i
;
957 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
959 tree label
, stmt
= bsi_stmt (i
);
961 if (TREE_CODE (stmt
) != LABEL_EXPR
)
964 label
= LABEL_EXPR_LABEL (stmt
);
966 /* If we have not yet seen a label for the current block,
967 remember this one and see if there are more labels. */
968 if (! label_for_bb
[bb
->index
])
970 label_for_bb
[bb
->index
] = label
;
974 /* If we did see a label for the current block already, but it
975 is an artificially created label, replace it if the current
976 label is a user defined label. */
977 if (! DECL_ARTIFICIAL (label
)
978 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
980 label_for_bb
[bb
->index
] = label
;
986 /* Now redirect all jumps/branches to the selected label.
987 First do so for each block ending in a control statement. */
990 tree stmt
= last_stmt (bb
);
994 switch (TREE_CODE (stmt
))
998 tree true_branch
, false_branch
;
1000 true_branch
= COND_EXPR_THEN (stmt
);
1001 false_branch
= COND_EXPR_ELSE (stmt
);
1003 GOTO_DESTINATION (true_branch
)
1004 = main_block_label (GOTO_DESTINATION (true_branch
));
1005 GOTO_DESTINATION (false_branch
)
1006 = main_block_label (GOTO_DESTINATION (false_branch
));
1014 tree vec
= SWITCH_LABELS (stmt
);
1015 size_t n
= TREE_VEC_LENGTH (vec
);
1017 /* Replace all destination labels. */
1018 for (i
= 0; i
< n
; ++i
)
1020 tree elt
= TREE_VEC_ELT (vec
, i
);
1021 tree label
= main_block_label (CASE_LABEL (elt
));
1022 CASE_LABEL (elt
) = label
;
1027 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1028 remove them until after we've created the CFG edges. */
1030 if (! computed_goto_p (stmt
))
1032 GOTO_DESTINATION (stmt
)
1033 = main_block_label (GOTO_DESTINATION (stmt
));
1042 for_each_eh_region (update_eh_label
);
1044 /* Finally, purge dead labels. All user-defined labels and labels that
1045 can be the target of non-local gotos and labels which have their
1046 address taken are preserved. */
1049 block_stmt_iterator i
;
1050 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1052 if (! label_for_this_bb
)
1055 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1057 tree label
, stmt
= bsi_stmt (i
);
1059 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1062 label
= LABEL_EXPR_LABEL (stmt
);
1064 if (label
== label_for_this_bb
1065 || ! DECL_ARTIFICIAL (label
)
1066 || DECL_NONLOCAL (label
)
1067 || FORCED_LABEL (label
))
1070 bsi_remove (&i
, true);
1074 free (label_for_bb
);
1077 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1078 and scan the sorted vector of cases. Combine the ones jumping to the
1080 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1083 group_case_labels (void)
1089 tree stmt
= last_stmt (bb
);
1090 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1092 tree labels
= SWITCH_LABELS (stmt
);
1093 int old_size
= TREE_VEC_LENGTH (labels
);
1094 int i
, j
, new_size
= old_size
;
1095 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1098 /* The default label is always the last case in a switch
1099 statement after gimplification. */
1100 default_label
= CASE_LABEL (default_case
);
1102 /* Look for possible opportunities to merge cases.
1103 Ignore the last element of the label vector because it
1104 must be the default case. */
1106 while (i
< old_size
- 1)
1108 tree base_case
, base_label
, base_high
;
1109 base_case
= TREE_VEC_ELT (labels
, i
);
1111 gcc_assert (base_case
);
1112 base_label
= CASE_LABEL (base_case
);
1114 /* Discard cases that have the same destination as the
1116 if (base_label
== default_label
)
1118 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1124 base_high
= CASE_HIGH (base_case
) ?
1125 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1127 /* Try to merge case labels. Break out when we reach the end
1128 of the label vector or when we cannot merge the next case
1129 label with the current one. */
1130 while (i
< old_size
- 1)
1132 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1133 tree merge_label
= CASE_LABEL (merge_case
);
1134 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1135 integer_one_node
, 1);
1137 /* Merge the cases if they jump to the same place,
1138 and their ranges are consecutive. */
1139 if (merge_label
== base_label
1140 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1142 base_high
= CASE_HIGH (merge_case
) ?
1143 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1144 CASE_HIGH (base_case
) = base_high
;
1145 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1154 /* Compress the case labels in the label vector, and adjust the
1155 length of the vector. */
1156 for (i
= 0, j
= 0; i
< new_size
; i
++)
1158 while (! TREE_VEC_ELT (labels
, j
))
1160 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1162 TREE_VEC_LENGTH (labels
) = new_size
;
1167 /* Checks whether we can merge block B into block A. */
1170 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1173 block_stmt_iterator bsi
;
1176 if (!single_succ_p (a
))
1179 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1182 if (single_succ (a
) != b
)
1185 if (!single_pred_p (b
))
1188 if (b
== EXIT_BLOCK_PTR
)
1191 /* If A ends by a statement causing exceptions or something similar, we
1192 cannot merge the blocks. */
1193 stmt
= last_stmt (a
);
1194 if (stmt
&& stmt_ends_bb_p (stmt
))
1197 /* Do not allow a block with only a non-local label to be merged. */
1198 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1199 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1202 /* It must be possible to eliminate all phi nodes in B. If ssa form
1203 is not up-to-date, we cannot eliminate any phis. */
1204 phi
= phi_nodes (b
);
1207 if (need_ssa_update_p ())
1210 for (; phi
; phi
= PHI_CHAIN (phi
))
1211 if (!is_gimple_reg (PHI_RESULT (phi
))
1212 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1216 /* Do not remove user labels. */
1217 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1219 stmt
= bsi_stmt (bsi
);
1220 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1222 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1226 /* Protect the loop latches. */
1228 && b
->loop_father
->latch
== b
)
1234 /* Replaces all uses of NAME by VAL. */
1237 replace_uses_by (tree name
, tree val
)
1239 imm_use_iterator imm_iter
;
1246 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, name
)
1248 FOR_EACH_IMM_USE_ON_STMT (use
, imm_iter
)
1250 replace_exp (use
, val
);
1252 if (TREE_CODE (stmt
) == PHI_NODE
)
1254 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1255 if (e
->flags
& EDGE_ABNORMAL
)
1257 /* This can only occur for virtual operands, since
1258 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1259 would prevent replacement. */
1260 gcc_assert (!is_gimple_reg (name
));
1261 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1265 if (TREE_CODE (stmt
) != PHI_NODE
)
1269 fold_stmt_inplace (stmt
);
1270 rhs
= get_rhs (stmt
);
1271 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1272 recompute_tree_invariant_for_addr_expr (rhs
);
1274 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1275 mark_new_vars_to_rename (stmt
);
1279 gcc_assert (num_imm_uses (name
) == 0);
1281 /* Also update the trees stored in loop structures. */
1286 for (i
= 0; i
< current_loops
->num
; i
++)
1288 loop
= current_loops
->parray
[i
];
1290 substitute_in_loop_info (loop
, name
, val
);
1295 /* Merge block B into block A. */
1298 tree_merge_blocks (basic_block a
, basic_block b
)
1300 block_stmt_iterator bsi
;
1301 tree_stmt_iterator last
;
1305 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1307 /* Remove all single-valued PHI nodes from block B of the form
1308 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1310 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1312 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1314 bool may_replace_uses
= may_propagate_copy (def
, use
);
1316 /* In case we have loops to care about, do not propagate arguments of
1317 loop closed ssa phi nodes. */
1319 && is_gimple_reg (def
)
1320 && TREE_CODE (use
) == SSA_NAME
1321 && a
->loop_father
!= b
->loop_father
)
1322 may_replace_uses
= false;
1324 if (!may_replace_uses
)
1326 gcc_assert (is_gimple_reg (def
));
1328 /* Note that just emitting the copies is fine -- there is no problem
1329 with ordering of phi nodes. This is because A is the single
1330 predecessor of B, therefore results of the phi nodes cannot
1331 appear as arguments of the phi nodes. */
1332 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1333 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1334 SET_PHI_RESULT (phi
, NULL_TREE
);
1335 SSA_NAME_DEF_STMT (def
) = copy
;
1338 replace_uses_by (def
, use
);
1340 remove_phi_node (phi
, NULL
);
1343 /* Ensure that B follows A. */
1344 move_block_after (b
, a
);
1346 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1347 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1349 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1350 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1352 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1354 tree label
= bsi_stmt (bsi
);
1356 bsi_remove (&bsi
, false);
1357 /* Now that we can thread computed gotos, we might have
1358 a situation where we have a forced label in block B
1359 However, the label at the start of block B might still be
1360 used in other ways (think about the runtime checking for
1361 Fortran assigned gotos). So we can not just delete the
1362 label. Instead we move the label to the start of block A. */
1363 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1365 block_stmt_iterator dest_bsi
= bsi_start (a
);
1366 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1371 change_bb_for_stmt (bsi_stmt (bsi
), a
);
1376 /* Merge the chains. */
1377 last
= tsi_last (a
->stmt_list
);
1378 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1379 b
->stmt_list
= NULL
;
1383 /* Return the one of two successors of BB that is not reachable by a
1384 reached by a complex edge, if there is one. Else, return BB. We use
1385 this in optimizations that use post-dominators for their heuristics,
1386 to catch the cases in C++ where function calls are involved. */
1389 single_noncomplex_succ (basic_block bb
)
1392 if (EDGE_COUNT (bb
->succs
) != 2)
1395 e0
= EDGE_SUCC (bb
, 0);
1396 e1
= EDGE_SUCC (bb
, 1);
1397 if (e0
->flags
& EDGE_COMPLEX
)
1399 if (e1
->flags
& EDGE_COMPLEX
)
1406 /* Walk the function tree removing unnecessary statements.
1408 * Empty statement nodes are removed
1410 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1412 * Unnecessary COND_EXPRs are removed
1414 * Some unnecessary BIND_EXPRs are removed
1416 Clearly more work could be done. The trick is doing the analysis
1417 and removal fast enough to be a net improvement in compile times.
1419 Note that when we remove a control structure such as a COND_EXPR
1420 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1421 to ensure we eliminate all the useless code. */
1432 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1435 remove_useless_stmts_warn_notreached (tree stmt
)
1437 if (EXPR_HAS_LOCATION (stmt
))
1439 location_t loc
= EXPR_LOCATION (stmt
);
1440 if (LOCATION_LINE (loc
) > 0)
1442 warning (0, "%Hwill never be executed", &loc
);
1447 switch (TREE_CODE (stmt
))
1449 case STATEMENT_LIST
:
1451 tree_stmt_iterator i
;
1452 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1453 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1459 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1461 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1463 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1467 case TRY_FINALLY_EXPR
:
1468 case TRY_CATCH_EXPR
:
1469 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1471 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1476 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1477 case EH_FILTER_EXPR
:
1478 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1480 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1483 /* Not a live container. */
1491 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1493 tree then_clause
, else_clause
, cond
;
1494 bool save_has_label
, then_has_label
, else_has_label
;
1496 save_has_label
= data
->has_label
;
1497 data
->has_label
= false;
1498 data
->last_goto
= NULL
;
1500 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1502 then_has_label
= data
->has_label
;
1503 data
->has_label
= false;
1504 data
->last_goto
= NULL
;
1506 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1508 else_has_label
= data
->has_label
;
1509 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1511 then_clause
= COND_EXPR_THEN (*stmt_p
);
1512 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1513 cond
= fold (COND_EXPR_COND (*stmt_p
));
1515 /* If neither arm does anything at all, we can remove the whole IF. */
1516 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1518 *stmt_p
= build_empty_stmt ();
1519 data
->repeat
= true;
1522 /* If there are no reachable statements in an arm, then we can
1523 zap the entire conditional. */
1524 else if (integer_nonzerop (cond
) && !else_has_label
)
1526 if (warn_notreached
)
1527 remove_useless_stmts_warn_notreached (else_clause
);
1528 *stmt_p
= then_clause
;
1529 data
->repeat
= true;
1531 else if (integer_zerop (cond
) && !then_has_label
)
1533 if (warn_notreached
)
1534 remove_useless_stmts_warn_notreached (then_clause
);
1535 *stmt_p
= else_clause
;
1536 data
->repeat
= true;
1539 /* Check a couple of simple things on then/else with single stmts. */
1542 tree then_stmt
= expr_only (then_clause
);
1543 tree else_stmt
= expr_only (else_clause
);
1545 /* Notice branches to a common destination. */
1546 if (then_stmt
&& else_stmt
1547 && TREE_CODE (then_stmt
) == GOTO_EXPR
1548 && TREE_CODE (else_stmt
) == GOTO_EXPR
1549 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1551 *stmt_p
= then_stmt
;
1552 data
->repeat
= true;
1555 /* If the THEN/ELSE clause merely assigns a value to a variable or
1556 parameter which is already known to contain that value, then
1557 remove the useless THEN/ELSE clause. */
1558 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1561 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1562 && TREE_OPERAND (else_stmt
, 0) == cond
1563 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1564 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1566 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1567 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1568 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1569 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1571 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1572 ? then_stmt
: else_stmt
);
1573 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1574 ? &COND_EXPR_THEN (*stmt_p
)
1575 : &COND_EXPR_ELSE (*stmt_p
));
1578 && TREE_CODE (stmt
) == MODIFY_EXPR
1579 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1580 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1581 *location
= alloc_stmt_list ();
1585 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1586 would be re-introduced during lowering. */
1587 data
->last_goto
= NULL
;
1592 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1594 bool save_may_branch
, save_may_throw
;
1595 bool this_may_branch
, this_may_throw
;
1597 /* Collect may_branch and may_throw information for the body only. */
1598 save_may_branch
= data
->may_branch
;
1599 save_may_throw
= data
->may_throw
;
1600 data
->may_branch
= false;
1601 data
->may_throw
= false;
1602 data
->last_goto
= NULL
;
1604 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1606 this_may_branch
= data
->may_branch
;
1607 this_may_throw
= data
->may_throw
;
1608 data
->may_branch
|= save_may_branch
;
1609 data
->may_throw
|= save_may_throw
;
1610 data
->last_goto
= NULL
;
1612 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1614 /* If the body is empty, then we can emit the FINALLY block without
1615 the enclosing TRY_FINALLY_EXPR. */
1616 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1618 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1619 data
->repeat
= true;
1622 /* If the handler is empty, then we can emit the TRY block without
1623 the enclosing TRY_FINALLY_EXPR. */
1624 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1626 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1627 data
->repeat
= true;
1630 /* If the body neither throws, nor branches, then we can safely
1631 string the TRY and FINALLY blocks together. */
1632 else if (!this_may_branch
&& !this_may_throw
)
1634 tree stmt
= *stmt_p
;
1635 *stmt_p
= TREE_OPERAND (stmt
, 0);
1636 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1637 data
->repeat
= true;
1643 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1645 bool save_may_throw
, this_may_throw
;
1646 tree_stmt_iterator i
;
1649 /* Collect may_throw information for the body only. */
1650 save_may_throw
= data
->may_throw
;
1651 data
->may_throw
= false;
1652 data
->last_goto
= NULL
;
1654 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1656 this_may_throw
= data
->may_throw
;
1657 data
->may_throw
= save_may_throw
;
1659 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1660 if (!this_may_throw
)
1662 if (warn_notreached
)
1663 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1664 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1665 data
->repeat
= true;
1669 /* Process the catch clause specially. We may be able to tell that
1670 no exceptions propagate past this point. */
1672 this_may_throw
= true;
1673 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1674 stmt
= tsi_stmt (i
);
1675 data
->last_goto
= NULL
;
1677 switch (TREE_CODE (stmt
))
1680 for (; !tsi_end_p (i
); tsi_next (&i
))
1682 stmt
= tsi_stmt (i
);
1683 /* If we catch all exceptions, then the body does not
1684 propagate exceptions past this point. */
1685 if (CATCH_TYPES (stmt
) == NULL
)
1686 this_may_throw
= false;
1687 data
->last_goto
= NULL
;
1688 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1692 case EH_FILTER_EXPR
:
1693 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1694 this_may_throw
= false;
1695 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1696 this_may_throw
= false;
1697 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1701 /* Otherwise this is a cleanup. */
1702 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1704 /* If the cleanup is empty, then we can emit the TRY block without
1705 the enclosing TRY_CATCH_EXPR. */
1706 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1708 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1709 data
->repeat
= true;
1713 data
->may_throw
|= this_may_throw
;
1718 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1722 /* First remove anything underneath the BIND_EXPR. */
1723 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1725 /* If the BIND_EXPR has no variables, then we can pull everything
1726 up one level and remove the BIND_EXPR, unless this is the toplevel
1727 BIND_EXPR for the current function or an inlined function.
1729 When this situation occurs we will want to apply this
1730 optimization again. */
1731 block
= BIND_EXPR_BLOCK (*stmt_p
);
1732 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1733 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1735 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1736 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1739 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1740 data
->repeat
= true;
1746 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1748 tree dest
= GOTO_DESTINATION (*stmt_p
);
1750 data
->may_branch
= true;
1751 data
->last_goto
= NULL
;
1753 /* Record the last goto expr, so that we can delete it if unnecessary. */
1754 if (TREE_CODE (dest
) == LABEL_DECL
)
1755 data
->last_goto
= stmt_p
;
1760 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1762 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1764 data
->has_label
= true;
1766 /* We do want to jump across non-local label receiver code. */
1767 if (DECL_NONLOCAL (label
))
1768 data
->last_goto
= NULL
;
1770 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1772 *data
->last_goto
= build_empty_stmt ();
1773 data
->repeat
= true;
1776 /* ??? Add something here to delete unused labels. */
1780 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1781 decl. This allows us to eliminate redundant or useless
1782 calls to "const" functions.
1784 Gimplifier already does the same operation, but we may notice functions
1785 being const and pure once their calls has been gimplified, so we need
1786 to update the flag. */
1789 update_call_expr_flags (tree call
)
1791 tree decl
= get_callee_fndecl (call
);
1794 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1795 TREE_SIDE_EFFECTS (call
) = 0;
1796 if (TREE_NOTHROW (decl
))
1797 TREE_NOTHROW (call
) = 1;
1801 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1804 notice_special_calls (tree t
)
1806 int flags
= call_expr_flags (t
);
1808 if (flags
& ECF_MAY_BE_ALLOCA
)
1809 current_function_calls_alloca
= true;
1810 if (flags
& ECF_RETURNS_TWICE
)
1811 current_function_calls_setjmp
= true;
1815 /* Clear flags set by notice_special_calls. Used by dead code removal
1816 to update the flags. */
1819 clear_special_calls (void)
1821 current_function_calls_alloca
= false;
1822 current_function_calls_setjmp
= false;
1827 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1831 switch (TREE_CODE (t
))
1834 remove_useless_stmts_cond (tp
, data
);
1837 case TRY_FINALLY_EXPR
:
1838 remove_useless_stmts_tf (tp
, data
);
1841 case TRY_CATCH_EXPR
:
1842 remove_useless_stmts_tc (tp
, data
);
1846 remove_useless_stmts_bind (tp
, data
);
1850 remove_useless_stmts_goto (tp
, data
);
1854 remove_useless_stmts_label (tp
, data
);
1859 data
->last_goto
= NULL
;
1860 data
->may_branch
= true;
1865 data
->last_goto
= NULL
;
1866 notice_special_calls (t
);
1867 update_call_expr_flags (t
);
1868 if (tree_could_throw_p (t
))
1869 data
->may_throw
= true;
1873 data
->last_goto
= NULL
;
1875 op
= get_call_expr_in (t
);
1878 update_call_expr_flags (op
);
1879 notice_special_calls (op
);
1881 if (tree_could_throw_p (t
))
1882 data
->may_throw
= true;
1885 case STATEMENT_LIST
:
1887 tree_stmt_iterator i
= tsi_start (t
);
1888 while (!tsi_end_p (i
))
1891 if (IS_EMPTY_STMT (t
))
1897 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1900 if (TREE_CODE (t
) == STATEMENT_LIST
)
1902 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1912 data
->last_goto
= NULL
;
1916 data
->last_goto
= NULL
;
1922 remove_useless_stmts (void)
1924 struct rus_data data
;
1926 clear_special_calls ();
1930 memset (&data
, 0, sizeof (data
));
1931 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1933 while (data
.repeat
);
1938 struct tree_opt_pass pass_remove_useless_stmts
=
1940 "useless", /* name */
1942 remove_useless_stmts
, /* execute */
1945 0, /* static_pass_number */
1947 PROP_gimple_any
, /* properties_required */
1948 0, /* properties_provided */
1949 0, /* properties_destroyed */
1950 0, /* todo_flags_start */
1951 TODO_dump_func
, /* todo_flags_finish */
1955 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1958 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1962 /* Since this block is no longer reachable, we can just delete all
1963 of its PHI nodes. */
1964 phi
= phi_nodes (bb
);
1967 tree next
= PHI_CHAIN (phi
);
1968 remove_phi_node (phi
, NULL_TREE
);
1972 /* Remove edges to BB's successors. */
1973 while (EDGE_COUNT (bb
->succs
) > 0)
1974 remove_edge (EDGE_SUCC (bb
, 0));
1978 /* Remove statements of basic block BB. */
1981 remove_bb (basic_block bb
)
1983 block_stmt_iterator i
;
1984 #ifdef USE_MAPPED_LOCATION
1985 source_location loc
= UNKNOWN_LOCATION
;
1987 source_locus loc
= 0;
1992 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1993 if (dump_flags
& TDF_DETAILS
)
1995 dump_bb (bb
, dump_file
, 0);
1996 fprintf (dump_file
, "\n");
2000 /* If we remove the header or the latch of a loop, mark the loop for
2001 removal by setting its header and latch to NULL. */
2004 struct loop
*loop
= bb
->loop_father
;
2006 if (loop
->latch
== bb
2007 || loop
->header
== bb
)
2010 loop
->header
= NULL
;
2012 /* Also clean up the information associated with the loop. Updating
2013 it would waste time. More importantly, it may refer to ssa
2014 names that were defined in other removed basic block -- these
2015 ssa names are now removed and invalid. */
2016 free_numbers_of_iterations_estimates_loop (loop
);
2020 /* Remove all the instructions in the block. */
2021 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2023 tree stmt
= bsi_stmt (i
);
2024 if (TREE_CODE (stmt
) == LABEL_EXPR
2025 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2026 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2029 block_stmt_iterator new_bsi
;
2031 /* A non-reachable non-local label may still be referenced.
2032 But it no longer needs to carry the extra semantics of
2034 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2036 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2037 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2040 new_bb
= bb
->prev_bb
;
2041 new_bsi
= bsi_start (new_bb
);
2042 bsi_remove (&i
, false);
2043 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2047 /* Release SSA definitions if we are in SSA. Note that we
2048 may be called when not in SSA. For example,
2049 final_cleanup calls this function via
2050 cleanup_tree_cfg. */
2052 release_defs (stmt
);
2054 bsi_remove (&i
, true);
2057 /* Don't warn for removed gotos. Gotos are often removed due to
2058 jump threading, thus resulting in bogus warnings. Not great,
2059 since this way we lose warnings for gotos in the original
2060 program that are indeed unreachable. */
2061 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2063 #ifdef USE_MAPPED_LOCATION
2064 if (EXPR_HAS_LOCATION (stmt
))
2065 loc
= EXPR_LOCATION (stmt
);
2068 t
= EXPR_LOCUS (stmt
);
2069 if (t
&& LOCATION_LINE (*t
) > 0)
2075 /* If requested, give a warning that the first statement in the
2076 block is unreachable. We walk statements backwards in the
2077 loop above, so the last statement we process is the first statement
2079 #ifdef USE_MAPPED_LOCATION
2080 if (loc
> BUILTINS_LOCATION
)
2081 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2084 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2087 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2091 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2092 predicate VAL, return the edge that will be taken out of the block.
2093 If VAL does not match a unique edge, NULL is returned. */
2096 find_taken_edge (basic_block bb
, tree val
)
2100 stmt
= last_stmt (bb
);
2103 gcc_assert (is_ctrl_stmt (stmt
));
2106 if (! is_gimple_min_invariant (val
))
2109 if (TREE_CODE (stmt
) == COND_EXPR
)
2110 return find_taken_edge_cond_expr (bb
, val
);
2112 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2113 return find_taken_edge_switch_expr (bb
, val
);
2115 if (computed_goto_p (stmt
))
2116 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2121 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2122 statement, determine which of the outgoing edges will be taken out of the
2123 block. Return NULL if either edge may be taken. */
2126 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2131 dest
= label_to_block (val
);
2134 e
= find_edge (bb
, dest
);
2135 gcc_assert (e
!= NULL
);
2141 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2142 statement, determine which of the two edges will be taken out of the
2143 block. Return NULL if either edge may be taken. */
2146 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2148 edge true_edge
, false_edge
;
2150 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2152 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2153 return (zero_p (val
) ? false_edge
: true_edge
);
2156 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2157 statement, determine which edge will be taken out of the block. Return
2158 NULL if any edge may be taken. */
2161 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2163 tree switch_expr
, taken_case
;
2164 basic_block dest_bb
;
2167 switch_expr
= last_stmt (bb
);
2168 taken_case
= find_case_label_for_value (switch_expr
, val
);
2169 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2171 e
= find_edge (bb
, dest_bb
);
2177 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2178 We can make optimal use here of the fact that the case labels are
2179 sorted: We can do a binary search for a case matching VAL. */
2182 find_case_label_for_value (tree switch_expr
, tree val
)
2184 tree vec
= SWITCH_LABELS (switch_expr
);
2185 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2186 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2188 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2190 size_t i
= (high
+ low
) / 2;
2191 tree t
= TREE_VEC_ELT (vec
, i
);
2194 /* Cache the result of comparing CASE_LOW and val. */
2195 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2202 if (CASE_HIGH (t
) == NULL
)
2204 /* A singe-valued case label. */
2210 /* A case range. We can only handle integer ranges. */
2211 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2216 return default_case
;
2222 /*---------------------------------------------------------------------------
2224 ---------------------------------------------------------------------------*/
2226 /* Dump tree-specific information of block BB to file OUTF. */
2229 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2231 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2235 /* Dump a basic block on stderr. */
2238 debug_tree_bb (basic_block bb
)
2240 dump_bb (bb
, stderr
, 0);
2244 /* Dump basic block with index N on stderr. */
2247 debug_tree_bb_n (int n
)
2249 debug_tree_bb (BASIC_BLOCK (n
));
2250 return BASIC_BLOCK (n
);
2254 /* Dump the CFG on stderr.
2256 FLAGS are the same used by the tree dumping functions
2257 (see TDF_* in tree-pass.h). */
2260 debug_tree_cfg (int flags
)
2262 dump_tree_cfg (stderr
, flags
);
2266 /* Dump the program showing basic block boundaries on the given FILE.
2268 FLAGS are the same used by the tree dumping functions (see TDF_* in
2272 dump_tree_cfg (FILE *file
, int flags
)
2274 if (flags
& TDF_DETAILS
)
2276 const char *funcname
2277 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2280 fprintf (file
, ";; Function %s\n\n", funcname
);
2281 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2282 n_basic_blocks
, n_edges
, last_basic_block
);
2284 brief_dump_cfg (file
);
2285 fprintf (file
, "\n");
2288 if (flags
& TDF_STATS
)
2289 dump_cfg_stats (file
);
2291 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2295 /* Dump CFG statistics on FILE. */
2298 dump_cfg_stats (FILE *file
)
2300 static long max_num_merged_labels
= 0;
2301 unsigned long size
, total
= 0;
2304 const char * const fmt_str
= "%-30s%-13s%12s\n";
2305 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2306 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2307 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2308 const char *funcname
2309 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2312 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2314 fprintf (file
, "---------------------------------------------------------\n");
2315 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2316 fprintf (file
, fmt_str
, "", " instances ", "used ");
2317 fprintf (file
, "---------------------------------------------------------\n");
2319 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2321 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2322 SCALE (size
), LABEL (size
));
2326 num_edges
+= EDGE_COUNT (bb
->succs
);
2327 size
= num_edges
* sizeof (struct edge_def
);
2329 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2331 fprintf (file
, "---------------------------------------------------------\n");
2332 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2334 fprintf (file
, "---------------------------------------------------------\n");
2335 fprintf (file
, "\n");
2337 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2338 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2340 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2341 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2343 fprintf (file
, "\n");
2347 /* Dump CFG statistics on stderr. Keep extern so that it's always
2348 linked in the final executable. */
2351 debug_cfg_stats (void)
2353 dump_cfg_stats (stderr
);
2357 /* Dump the flowgraph to a .vcg FILE. */
2360 tree_cfg2vcg (FILE *file
)
2365 const char *funcname
2366 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2368 /* Write the file header. */
2369 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2370 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2371 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2373 /* Write blocks and edges. */
2374 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2376 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2379 if (e
->flags
& EDGE_FAKE
)
2380 fprintf (file
, " linestyle: dotted priority: 10");
2382 fprintf (file
, " linestyle: solid priority: 100");
2384 fprintf (file
, " }\n");
2390 enum tree_code head_code
, end_code
;
2391 const char *head_name
, *end_name
;
2394 tree first
= first_stmt (bb
);
2395 tree last
= last_stmt (bb
);
2399 head_code
= TREE_CODE (first
);
2400 head_name
= tree_code_name
[head_code
];
2401 head_line
= get_lineno (first
);
2404 head_name
= "no-statement";
2408 end_code
= TREE_CODE (last
);
2409 end_name
= tree_code_name
[end_code
];
2410 end_line
= get_lineno (last
);
2413 end_name
= "no-statement";
2415 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2416 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2419 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2421 if (e
->dest
== EXIT_BLOCK_PTR
)
2422 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2424 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2426 if (e
->flags
& EDGE_FAKE
)
2427 fprintf (file
, " priority: 10 linestyle: dotted");
2429 fprintf (file
, " priority: 100 linestyle: solid");
2431 fprintf (file
, " }\n");
2434 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2438 fputs ("}\n\n", file
);
2443 /*---------------------------------------------------------------------------
2444 Miscellaneous helpers
2445 ---------------------------------------------------------------------------*/
2447 /* Return true if T represents a stmt that always transfers control. */
2450 is_ctrl_stmt (tree t
)
2452 return (TREE_CODE (t
) == COND_EXPR
2453 || TREE_CODE (t
) == SWITCH_EXPR
2454 || TREE_CODE (t
) == GOTO_EXPR
2455 || TREE_CODE (t
) == RETURN_EXPR
2456 || TREE_CODE (t
) == RESX_EXPR
);
2460 /* Return true if T is a statement that may alter the flow of control
2461 (e.g., a call to a non-returning function). */
2464 is_ctrl_altering_stmt (tree t
)
2469 call
= get_call_expr_in (t
);
2472 /* A non-pure/const CALL_EXPR alters flow control if the current
2473 function has nonlocal labels. */
2474 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2477 /* A CALL_EXPR also alters control flow if it does not return. */
2478 if (call_expr_flags (call
) & ECF_NORETURN
)
2482 /* OpenMP directives alter control flow. */
2483 if (OMP_DIRECTIVE_P (t
))
2486 /* If a statement can throw, it alters control flow. */
2487 return tree_can_throw_internal (t
);
2491 /* Return true if T is a computed goto. */
2494 computed_goto_p (tree t
)
2496 return (TREE_CODE (t
) == GOTO_EXPR
2497 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2501 /* Return true if T is a simple local goto. */
2504 simple_goto_p (tree t
)
2506 return (TREE_CODE (t
) == GOTO_EXPR
2507 && TREE_CODE (GOTO_DESTINATION (t
)) == LABEL_DECL
);
2511 /* Return true if T can make an abnormal transfer of control flow.
2512 Transfers of control flow associated with EH are excluded. */
2515 tree_can_make_abnormal_goto (tree t
)
2517 if (computed_goto_p (t
))
2519 if (TREE_CODE (t
) == MODIFY_EXPR
)
2520 t
= TREE_OPERAND (t
, 1);
2521 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2522 t
= TREE_OPERAND (t
, 0);
2523 if (TREE_CODE (t
) == CALL_EXPR
)
2524 return TREE_SIDE_EFFECTS (t
) && current_function_has_nonlocal_label
;
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 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2782 from one basic block to another.
2783 For BB splitting we can run into quadratic case, so performance is quite
2784 important and knowing that the tables are big enough, change_bb_for_stmt
2785 can inline as leaf function. */
2787 change_bb_for_stmt (tree t
, basic_block bb
)
2789 get_stmt_ann (t
)->bb
= bb
;
2790 if (TREE_CODE (t
) == LABEL_EXPR
)
2791 VEC_replace (basic_block
, label_to_block_map
,
2792 LABEL_DECL_UID (LABEL_EXPR_LABEL (t
)), bb
);
2795 /* Finds iterator for STMT. */
2797 extern block_stmt_iterator
2798 bsi_for_stmt (tree stmt
)
2800 block_stmt_iterator bsi
;
2802 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2803 if (bsi_stmt (bsi
) == stmt
)
2809 /* Mark statement T as modified, and update it. */
2811 update_modified_stmts (tree t
)
2813 if (TREE_CODE (t
) == STATEMENT_LIST
)
2815 tree_stmt_iterator i
;
2817 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2819 stmt
= tsi_stmt (i
);
2820 update_stmt_if_modified (stmt
);
2824 update_stmt_if_modified (t
);
2827 /* Insert statement (or statement list) T before the statement
2828 pointed-to by iterator I. M specifies how to update iterator I
2829 after insertion (see enum bsi_iterator_update). */
2832 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2834 set_bb_for_stmt (t
, i
->bb
);
2835 update_modified_stmts (t
);
2836 tsi_link_before (&i
->tsi
, t
, m
);
2840 /* Insert statement (or statement list) T after the statement
2841 pointed-to by iterator I. M specifies how to update iterator I
2842 after insertion (see enum bsi_iterator_update). */
2845 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2847 set_bb_for_stmt (t
, i
->bb
);
2848 update_modified_stmts (t
);
2849 tsi_link_after (&i
->tsi
, t
, m
);
2853 /* Remove the statement pointed to by iterator I. The iterator is updated
2854 to the next statement.
2856 When REMOVE_EH_INFO is true we remove the statement pointed to by
2857 iterator I from the EH tables. Otherwise we do not modify the EH
2860 Generally, REMOVE_EH_INFO should be true when the statement is going to
2861 be removed from the IL and not reinserted elsewhere. */
2864 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2866 tree t
= bsi_stmt (*i
);
2867 set_bb_for_stmt (t
, NULL
);
2868 delink_stmt_imm_use (t
);
2869 tsi_delink (&i
->tsi
);
2870 mark_stmt_modified (t
);
2872 remove_stmt_from_eh_region (t
);
2876 /* Move the statement at FROM so it comes right after the statement at TO. */
2879 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2881 tree stmt
= bsi_stmt (*from
);
2882 bsi_remove (from
, false);
2883 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2887 /* Move the statement at FROM so it comes right before the statement at TO. */
2890 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2892 tree stmt
= bsi_stmt (*from
);
2893 bsi_remove (from
, false);
2894 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2898 /* Move the statement at FROM to the end of basic block BB. */
2901 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2903 block_stmt_iterator last
= bsi_last (bb
);
2905 /* Have to check bsi_end_p because it could be an empty block. */
2906 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2907 bsi_move_before (from
, &last
);
2909 bsi_move_after (from
, &last
);
2913 /* Replace the contents of the statement pointed to by iterator BSI
2914 with STMT. If UPDATE_EH_INFO is true, the exception handling
2915 information of the original statement is moved to the new statement. */
2918 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2921 tree orig_stmt
= bsi_stmt (*bsi
);
2923 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2924 set_bb_for_stmt (stmt
, bsi
->bb
);
2926 /* Preserve EH region information from the original statement, if
2927 requested by the caller. */
2930 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2933 remove_stmt_from_eh_region (orig_stmt
);
2934 add_stmt_to_eh_region (stmt
, eh_region
);
2938 delink_stmt_imm_use (orig_stmt
);
2939 *bsi_stmt_ptr (*bsi
) = stmt
;
2940 mark_stmt_modified (stmt
);
2941 update_modified_stmts (stmt
);
2945 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2946 is made to place the statement in an existing basic block, but
2947 sometimes that isn't possible. When it isn't possible, the edge is
2948 split and the statement is added to the new block.
2950 In all cases, the returned *BSI points to the correct location. The
2951 return value is true if insertion should be done after the location,
2952 or false if it should be done before the location. If new basic block
2953 has to be created, it is stored in *NEW_BB. */
2956 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2957 basic_block
*new_bb
)
2959 basic_block dest
, src
;
2965 /* If the destination has one predecessor which has no PHI nodes,
2966 insert there. Except for the exit block.
2968 The requirement for no PHI nodes could be relaxed. Basically we
2969 would have to examine the PHIs to prove that none of them used
2970 the value set by the statement we want to insert on E. That
2971 hardly seems worth the effort. */
2972 if (single_pred_p (dest
)
2973 && ! phi_nodes (dest
)
2974 && dest
!= EXIT_BLOCK_PTR
)
2976 *bsi
= bsi_start (dest
);
2977 if (bsi_end_p (*bsi
))
2980 /* Make sure we insert after any leading labels. */
2981 tmp
= bsi_stmt (*bsi
);
2982 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2985 if (bsi_end_p (*bsi
))
2987 tmp
= bsi_stmt (*bsi
);
2990 if (bsi_end_p (*bsi
))
2992 *bsi
= bsi_last (dest
);
2999 /* If the source has one successor, the edge is not abnormal and
3000 the last statement does not end a basic block, insert there.
3001 Except for the entry block. */
3003 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3004 && single_succ_p (src
)
3005 && src
!= ENTRY_BLOCK_PTR
)
3007 *bsi
= bsi_last (src
);
3008 if (bsi_end_p (*bsi
))
3011 tmp
= bsi_stmt (*bsi
);
3012 if (!stmt_ends_bb_p (tmp
))
3015 /* Insert code just before returning the value. We may need to decompose
3016 the return in the case it contains non-trivial operand. */
3017 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3019 tree op
= TREE_OPERAND (tmp
, 0);
3020 if (op
&& !is_gimple_val (op
))
3022 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3023 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3024 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3031 /* Otherwise, create a new basic block, and split this edge. */
3032 dest
= split_edge (e
);
3035 e
= single_pred_edge (dest
);
3040 /* This routine will commit all pending edge insertions, creating any new
3041 basic blocks which are necessary. */
3044 bsi_commit_edge_inserts (void)
3050 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3053 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3054 bsi_commit_one_edge_insert (e
, NULL
);
3058 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3059 to this block, otherwise set it to NULL. */
3062 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3066 if (PENDING_STMT (e
))
3068 block_stmt_iterator bsi
;
3069 tree stmt
= PENDING_STMT (e
);
3071 PENDING_STMT (e
) = NULL_TREE
;
3073 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3074 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3076 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3081 /* Add STMT to the pending list of edge E. No actual insertion is
3082 made until a call to bsi_commit_edge_inserts () is made. */
3085 bsi_insert_on_edge (edge e
, tree stmt
)
3087 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3090 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3091 block has to be created, it is returned. */
3094 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3096 block_stmt_iterator bsi
;
3097 basic_block new_bb
= NULL
;
3099 gcc_assert (!PENDING_STMT (e
));
3101 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3102 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3104 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3109 /*---------------------------------------------------------------------------
3110 Tree specific functions for CFG manipulation
3111 ---------------------------------------------------------------------------*/
3113 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3116 reinstall_phi_args (edge new_edge
, edge old_edge
)
3120 if (!PENDING_STMT (old_edge
))
3123 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3125 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3127 tree result
= TREE_PURPOSE (var
);
3128 tree arg
= TREE_VALUE (var
);
3130 gcc_assert (result
== PHI_RESULT (phi
));
3132 add_phi_arg (phi
, arg
, new_edge
);
3135 PENDING_STMT (old_edge
) = NULL
;
3138 /* Returns the basic block after which the new basic block created
3139 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3140 near its "logical" location. This is of most help to humans looking
3141 at debugging dumps. */
3144 split_edge_bb_loc (edge edge_in
)
3146 basic_block dest
= edge_in
->dest
;
3148 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3149 return edge_in
->src
;
3151 return dest
->prev_bb
;
3154 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3155 Abort on abnormal edges. */
3158 tree_split_edge (edge edge_in
)
3160 basic_block new_bb
, after_bb
, dest
;
3163 /* Abnormal edges cannot be split. */
3164 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3166 dest
= edge_in
->dest
;
3168 after_bb
= split_edge_bb_loc (edge_in
);
3170 new_bb
= create_empty_bb (after_bb
);
3171 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3172 new_bb
->count
= edge_in
->count
;
3173 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3174 new_edge
->probability
= REG_BR_PROB_BASE
;
3175 new_edge
->count
= edge_in
->count
;
3177 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3179 reinstall_phi_args (new_edge
, e
);
3185 /* Return true when BB has label LABEL in it. */
3188 has_label_p (basic_block bb
, tree label
)
3190 block_stmt_iterator bsi
;
3192 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3194 tree stmt
= bsi_stmt (bsi
);
3196 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3198 if (LABEL_EXPR_LABEL (stmt
) == label
)
3205 /* Callback for walk_tree, check that all elements with address taken are
3206 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3207 inside a PHI node. */
3210 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3213 bool in_phi
= (data
!= NULL
);
3218 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3219 #define CHECK_OP(N, MSG) \
3220 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3221 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3223 switch (TREE_CODE (t
))
3226 if (SSA_NAME_IN_FREE_LIST (t
))
3228 error ("SSA name in freelist but still referenced");
3234 x
= fold (ASSERT_EXPR_COND (t
));
3235 if (x
== boolean_false_node
)
3237 error ("ASSERT_EXPR with an always-false condition");
3243 x
= TREE_OPERAND (t
, 0);
3244 if (TREE_CODE (x
) == BIT_FIELD_REF
3245 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3247 error ("GIMPLE register modified with BIT_FIELD_REF");
3256 bool old_side_effects
;
3259 bool new_side_effects
;
3261 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3262 dead PHIs that take the address of something. But if the PHI
3263 result is dead, the fact that it takes the address of anything
3264 is irrelevant. Because we can not tell from here if a PHI result
3265 is dead, we just skip this check for PHIs altogether. This means
3266 we may be missing "valid" checks, but what can you do?
3267 This was PR19217. */
3271 old_invariant
= TREE_INVARIANT (t
);
3272 old_constant
= TREE_CONSTANT (t
);
3273 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3275 recompute_tree_invariant_for_addr_expr (t
);
3276 new_invariant
= TREE_INVARIANT (t
);
3277 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3278 new_constant
= TREE_CONSTANT (t
);
3280 if (old_invariant
!= new_invariant
)
3282 error ("invariant not recomputed when ADDR_EXPR changed");
3286 if (old_constant
!= new_constant
)
3288 error ("constant not recomputed when ADDR_EXPR changed");
3291 if (old_side_effects
!= new_side_effects
)
3293 error ("side effects not recomputed when ADDR_EXPR changed");
3297 /* Skip any references (they will be checked when we recurse down the
3298 tree) and ensure that any variable used as a prefix is marked
3300 for (x
= TREE_OPERAND (t
, 0);
3301 handled_component_p (x
);
3302 x
= TREE_OPERAND (x
, 0))
3305 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3307 if (!TREE_ADDRESSABLE (x
))
3309 error ("address taken, but ADDRESSABLE bit not set");
3316 x
= COND_EXPR_COND (t
);
3317 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3319 error ("non-boolean used in condition");
3322 if (!is_gimple_condexpr (x
))
3324 error ("invalid conditional operand");
3331 case FIX_TRUNC_EXPR
:
3336 case NON_LVALUE_EXPR
:
3337 case TRUTH_NOT_EXPR
:
3338 CHECK_OP (0, "invalid operand to unary operator");
3345 case ARRAY_RANGE_REF
:
3347 case VIEW_CONVERT_EXPR
:
3348 /* We have a nest of references. Verify that each of the operands
3349 that determine where to reference is either a constant or a variable,
3350 verify that the base is valid, and then show we've already checked
3352 while (handled_component_p (t
))
3354 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3355 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3356 else if (TREE_CODE (t
) == ARRAY_REF
3357 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3359 CHECK_OP (1, "invalid array index");
3360 if (TREE_OPERAND (t
, 2))
3361 CHECK_OP (2, "invalid array lower bound");
3362 if (TREE_OPERAND (t
, 3))
3363 CHECK_OP (3, "invalid array stride");
3365 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3367 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3368 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3371 t
= TREE_OPERAND (t
, 0);
3374 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3376 error ("invalid reference prefix");
3388 case UNORDERED_EXPR
:
3399 case TRUNC_DIV_EXPR
:
3401 case FLOOR_DIV_EXPR
:
3402 case ROUND_DIV_EXPR
:
3403 case TRUNC_MOD_EXPR
:
3405 case FLOOR_MOD_EXPR
:
3406 case ROUND_MOD_EXPR
:
3408 case EXACT_DIV_EXPR
:
3418 CHECK_OP (0, "invalid operand to binary operator");
3419 CHECK_OP (1, "invalid operand to binary operator");
3431 /* Verify STMT, return true if STMT is not in GIMPLE form.
3432 TODO: Implement type checking. */
3435 verify_stmt (tree stmt
, bool last_in_block
)
3439 if (OMP_DIRECTIVE_P (stmt
))
3441 /* OpenMP directives are validated by the FE and never operated
3442 on by the optimizers. Furthermore, OMP_FOR may contain
3443 non-gimple expressions when the main index variable has had
3444 its address taken. This does not affect the loop itself
3445 because the header of an OMP_FOR is merely used to determine
3446 how to setup the parallel iteration. */
3450 if (!is_gimple_stmt (stmt
))
3452 error ("is not a valid GIMPLE statement");
3456 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3459 debug_generic_stmt (addr
);
3463 /* If the statement is marked as part of an EH region, then it is
3464 expected that the statement could throw. Verify that when we
3465 have optimizations that simplify statements such that we prove
3466 that they cannot throw, that we update other data structures
3468 if (lookup_stmt_eh_region (stmt
) >= 0)
3470 if (!tree_could_throw_p (stmt
))
3472 error ("statement marked for throw, but doesn%'t");
3475 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3477 error ("statement marked for throw in middle of block");
3485 debug_generic_stmt (stmt
);
3490 /* Return true when the T can be shared. */
3493 tree_node_can_be_shared (tree t
)
3495 if (IS_TYPE_OR_DECL_P (t
)
3496 || is_gimple_min_invariant (t
)
3497 || TREE_CODE (t
) == SSA_NAME
3498 || t
== error_mark_node
3499 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3502 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3505 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3506 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3507 || TREE_CODE (t
) == COMPONENT_REF
3508 || TREE_CODE (t
) == REALPART_EXPR
3509 || TREE_CODE (t
) == IMAGPART_EXPR
)
3510 t
= TREE_OPERAND (t
, 0);
3519 /* Called via walk_trees. Verify tree sharing. */
3522 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3524 htab_t htab
= (htab_t
) data
;
3527 if (tree_node_can_be_shared (*tp
))
3529 *walk_subtrees
= false;
3533 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3535 return (tree
) *slot
;
3542 /* Verify the GIMPLE statement chain. */
3548 block_stmt_iterator bsi
;
3553 timevar_push (TV_TREE_STMT_VERIFY
);
3554 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3561 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3563 int phi_num_args
= PHI_NUM_ARGS (phi
);
3565 if (bb_for_stmt (phi
) != bb
)
3567 error ("bb_for_stmt (phi) is set to a wrong basic block");
3571 for (i
= 0; i
< phi_num_args
; i
++)
3573 tree t
= PHI_ARG_DEF (phi
, i
);
3576 /* Addressable variables do have SSA_NAMEs but they
3577 are not considered gimple values. */
3578 if (TREE_CODE (t
) != SSA_NAME
3579 && TREE_CODE (t
) != FUNCTION_DECL
3580 && !is_gimple_val (t
))
3582 error ("PHI def is not a GIMPLE value");
3583 debug_generic_stmt (phi
);
3584 debug_generic_stmt (t
);
3588 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3591 debug_generic_stmt (addr
);
3595 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3598 error ("incorrect sharing of tree nodes");
3599 debug_generic_stmt (phi
);
3600 debug_generic_stmt (addr
);
3606 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3608 tree stmt
= bsi_stmt (bsi
);
3610 if (bb_for_stmt (stmt
) != bb
)
3612 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3617 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3618 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3621 error ("incorrect sharing of tree nodes");
3622 debug_generic_stmt (stmt
);
3623 debug_generic_stmt (addr
);
3630 internal_error ("verify_stmts failed");
3633 timevar_pop (TV_TREE_STMT_VERIFY
);
3637 /* Verifies that the flow information is OK. */
3640 tree_verify_flow_info (void)
3644 block_stmt_iterator bsi
;
3649 if (ENTRY_BLOCK_PTR
->stmt_list
)
3651 error ("ENTRY_BLOCK has a statement list associated with it");
3655 if (EXIT_BLOCK_PTR
->stmt_list
)
3657 error ("EXIT_BLOCK has a statement list associated with it");
3661 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3662 if (e
->flags
& EDGE_FALLTHRU
)
3664 error ("fallthru to exit from bb %d", e
->src
->index
);
3670 bool found_ctrl_stmt
= false;
3674 /* Skip labels on the start of basic block. */
3675 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3677 tree prev_stmt
= stmt
;
3679 stmt
= bsi_stmt (bsi
);
3681 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3684 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3686 error ("nonlocal label ");
3687 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3688 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3693 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3696 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3697 fprintf (stderr
, " to block does not match in bb %d",
3702 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3703 != current_function_decl
)
3706 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3707 fprintf (stderr
, " has incorrect context in bb %d",
3713 /* Verify that body of basic block BB is free of control flow. */
3714 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3716 tree stmt
= bsi_stmt (bsi
);
3718 if (found_ctrl_stmt
)
3720 error ("control flow in the middle of basic block %d",
3725 if (stmt_ends_bb_p (stmt
))
3726 found_ctrl_stmt
= true;
3728 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3731 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3732 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3737 bsi
= bsi_last (bb
);
3738 if (bsi_end_p (bsi
))
3741 stmt
= bsi_stmt (bsi
);
3743 err
|= verify_eh_edges (stmt
);
3745 if (is_ctrl_stmt (stmt
))
3747 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3748 if (e
->flags
& EDGE_FALLTHRU
)
3750 error ("fallthru edge after a control statement in bb %d",
3756 if (TREE_CODE (stmt
) != COND_EXPR
)
3758 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3759 after anything else but if statement. */
3760 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3761 if (e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
))
3763 error ("true/false edge after a non-COND_EXPR in bb %d",
3769 switch (TREE_CODE (stmt
))
3775 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3776 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3778 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3782 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3784 if (!true_edge
|| !false_edge
3785 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3786 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3787 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3788 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3789 || EDGE_COUNT (bb
->succs
) >= 3)
3791 error ("wrong outgoing edge flags at end of bb %d",
3796 if (!has_label_p (true_edge
->dest
,
3797 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3799 error ("%<then%> label does not match edge at end of bb %d",
3804 if (!has_label_p (false_edge
->dest
,
3805 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3807 error ("%<else%> label does not match edge at end of bb %d",
3815 if (simple_goto_p (stmt
))
3817 error ("explicit goto at end of bb %d", bb
->index
);
3822 /* FIXME. We should double check that the labels in the
3823 destination blocks have their address taken. */
3824 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3825 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3826 | EDGE_FALSE_VALUE
))
3827 || !(e
->flags
& EDGE_ABNORMAL
))
3829 error ("wrong outgoing edge flags at end of bb %d",
3837 if (!single_succ_p (bb
)
3838 || (single_succ_edge (bb
)->flags
3839 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3840 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3842 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3845 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3847 error ("return edge does not point to exit in bb %d",
3860 vec
= SWITCH_LABELS (stmt
);
3861 n
= TREE_VEC_LENGTH (vec
);
3863 /* Mark all the destination basic blocks. */
3864 for (i
= 0; i
< n
; ++i
)
3866 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3867 basic_block label_bb
= label_to_block (lab
);
3869 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3870 label_bb
->aux
= (void *)1;
3873 /* Verify that the case labels are sorted. */
3874 prev
= TREE_VEC_ELT (vec
, 0);
3875 for (i
= 1; i
< n
- 1; ++i
)
3877 tree c
= TREE_VEC_ELT (vec
, i
);
3880 error ("found default case not at end of case vector");
3884 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3886 error ("case labels not sorted: ");
3887 print_generic_expr (stderr
, prev
, 0);
3888 fprintf (stderr
," is greater than ");
3889 print_generic_expr (stderr
, c
, 0);
3890 fprintf (stderr
," but comes before it.\n");
3895 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3897 error ("no default case found at end of case vector");
3901 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3905 error ("extra outgoing edge %d->%d",
3906 bb
->index
, e
->dest
->index
);
3909 e
->dest
->aux
= (void *)2;
3910 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3911 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3913 error ("wrong outgoing edge flags at end of bb %d",
3919 /* Check that we have all of them. */
3920 for (i
= 0; i
< n
; ++i
)
3922 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3923 basic_block label_bb
= label_to_block (lab
);
3925 if (label_bb
->aux
!= (void *)2)
3927 error ("missing edge %i->%i",
3928 bb
->index
, label_bb
->index
);
3933 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3934 e
->dest
->aux
= (void *)0;
3941 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3942 verify_dominators (CDI_DOMINATORS
);
3948 /* Updates phi nodes after creating a forwarder block joined
3949 by edge FALLTHRU. */
3952 tree_make_forwarder_block (edge fallthru
)
3956 basic_block dummy
, bb
;
3957 tree phi
, new_phi
, var
;
3959 dummy
= fallthru
->src
;
3960 bb
= fallthru
->dest
;
3962 if (single_pred_p (bb
))
3965 /* If we redirected a branch we must create new phi nodes at the
3967 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3969 var
= PHI_RESULT (phi
);
3970 new_phi
= create_phi_node (var
, bb
);
3971 SSA_NAME_DEF_STMT (var
) = new_phi
;
3972 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3973 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3976 /* Ensure that the PHI node chain is in the same order. */
3977 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3979 /* Add the arguments we have stored on edges. */
3980 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3985 flush_pending_stmts (e
);
3990 /* Return a non-special label in the head of basic block BLOCK.
3991 Create one if it doesn't exist. */
3994 tree_block_label (basic_block bb
)
3996 block_stmt_iterator i
, s
= bsi_start (bb
);
4000 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4002 stmt
= bsi_stmt (i
);
4003 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4005 label
= LABEL_EXPR_LABEL (stmt
);
4006 if (!DECL_NONLOCAL (label
))
4009 bsi_move_before (&i
, &s
);
4014 label
= create_artificial_label ();
4015 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4016 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4021 /* Attempt to perform edge redirection by replacing a possibly complex
4022 jump instruction by a goto or by removing the jump completely.
4023 This can apply only if all edges now point to the same block. The
4024 parameters and return values are equivalent to
4025 redirect_edge_and_branch. */
4028 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4030 basic_block src
= e
->src
;
4031 block_stmt_iterator b
;
4034 /* We can replace or remove a complex jump only when we have exactly
4036 if (EDGE_COUNT (src
->succs
) != 2
4037 /* Verify that all targets will be TARGET. Specifically, the
4038 edge that is not E must also go to TARGET. */
4039 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4045 stmt
= bsi_stmt (b
);
4047 if (TREE_CODE (stmt
) == COND_EXPR
4048 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4050 bsi_remove (&b
, true);
4051 e
= ssa_redirect_edge (e
, target
);
4052 e
->flags
= EDGE_FALLTHRU
;
4060 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4061 edge representing the redirected branch. */
4064 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4066 basic_block bb
= e
->src
;
4067 block_stmt_iterator bsi
;
4071 if (e
->flags
& EDGE_ABNORMAL
)
4074 if (e
->src
!= ENTRY_BLOCK_PTR
4075 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4078 if (e
->dest
== dest
)
4081 label
= tree_block_label (dest
);
4083 bsi
= bsi_last (bb
);
4084 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4086 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4089 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4090 ? COND_EXPR_THEN (stmt
)
4091 : COND_EXPR_ELSE (stmt
));
4092 GOTO_DESTINATION (stmt
) = label
;
4096 /* No non-abnormal edges should lead from a non-simple goto, and
4097 simple ones should be represented implicitly. */
4102 tree cases
= get_cases_for_edge (e
, stmt
);
4104 /* If we have a list of cases associated with E, then use it
4105 as it's a lot faster than walking the entire case vector. */
4108 edge e2
= find_edge (e
->src
, dest
);
4115 CASE_LABEL (cases
) = label
;
4116 cases
= TREE_CHAIN (cases
);
4119 /* If there was already an edge in the CFG, then we need
4120 to move all the cases associated with E to E2. */
4123 tree cases2
= get_cases_for_edge (e2
, stmt
);
4125 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4126 TREE_CHAIN (cases2
) = first
;
4131 tree vec
= SWITCH_LABELS (stmt
);
4132 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4134 for (i
= 0; i
< n
; i
++)
4136 tree elt
= TREE_VEC_ELT (vec
, i
);
4138 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4139 CASE_LABEL (elt
) = label
;
4147 bsi_remove (&bsi
, true);
4148 e
->flags
|= EDGE_FALLTHRU
;
4152 /* Otherwise it must be a fallthru edge, and we don't need to
4153 do anything besides redirecting it. */
4154 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4158 /* Update/insert PHI nodes as necessary. */
4160 /* Now update the edges in the CFG. */
4161 e
= ssa_redirect_edge (e
, dest
);
4167 /* Simple wrapper, as we can always redirect fallthru edges. */
4170 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4172 e
= tree_redirect_edge_and_branch (e
, dest
);
4179 /* Splits basic block BB after statement STMT (but at least after the
4180 labels). If STMT is NULL, BB is split just after the labels. */
4183 tree_split_block (basic_block bb
, void *stmt
)
4185 block_stmt_iterator bsi
;
4186 tree_stmt_iterator tsi_tgt
;
4192 new_bb
= create_empty_bb (bb
);
4194 /* Redirect the outgoing edges. */
4195 new_bb
->succs
= bb
->succs
;
4197 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4200 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4203 /* Move everything from BSI to the new basic block. */
4204 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4206 act
= bsi_stmt (bsi
);
4207 if (TREE_CODE (act
) == LABEL_EXPR
)
4220 if (bsi_end_p (bsi
))
4223 /* Split the statement list - avoid re-creating new containers as this
4224 brings ugly quadratic memory consumption in the inliner.
4225 (We are still quadratic since we need to update stmt BB pointers,
4227 new_bb
->stmt_list
= tsi_split_statement_list_before (&bsi
.tsi
);
4228 for (tsi_tgt
= tsi_start (new_bb
->stmt_list
);
4229 !tsi_end_p (tsi_tgt
); tsi_next (&tsi_tgt
))
4230 change_bb_for_stmt (tsi_stmt (tsi_tgt
), new_bb
);
4236 /* Moves basic block BB after block AFTER. */
4239 tree_move_block_after (basic_block bb
, basic_block after
)
4241 if (bb
->prev_bb
== after
)
4245 link_block (bb
, after
);
4251 /* Return true if basic_block can be duplicated. */
4254 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4260 /* Create a duplicate of the basic block BB. NOTE: This does not
4261 preserve SSA form. */
4264 tree_duplicate_bb (basic_block bb
)
4267 block_stmt_iterator bsi
, bsi_tgt
;
4270 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4272 /* Copy the PHI nodes. We ignore PHI node arguments here because
4273 the incoming edges have not been setup yet. */
4274 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4276 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4277 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4280 /* Keep the chain of PHI nodes in the same order so that they can be
4281 updated by ssa_redirect_edge. */
4282 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4284 bsi_tgt
= bsi_start (new_bb
);
4285 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4287 def_operand_p def_p
;
4288 ssa_op_iter op_iter
;
4292 stmt
= bsi_stmt (bsi
);
4293 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4296 /* Create a new copy of STMT and duplicate STMT's virtual
4298 copy
= unshare_expr (stmt
);
4299 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4300 copy_virtual_operands (copy
, stmt
);
4301 region
= lookup_stmt_eh_region (stmt
);
4303 add_stmt_to_eh_region (copy
, region
);
4305 /* Create new names for all the definitions created by COPY and
4306 add replacement mappings for each new name. */
4307 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4308 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4315 /* Basic block BB_COPY was created by code duplication. Add phi node
4316 arguments for edges going out of BB_COPY. The blocks that were
4317 duplicated have BB_DUPLICATED set. */
4320 add_phi_args_after_copy_bb (basic_block bb_copy
)
4322 basic_block bb
, dest
;
4325 tree phi
, phi_copy
, phi_next
, def
;
4327 bb
= get_bb_original (bb_copy
);
4329 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4331 if (!phi_nodes (e_copy
->dest
))
4334 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4335 dest
= get_bb_original (e_copy
->dest
);
4337 dest
= e_copy
->dest
;
4339 e
= find_edge (bb
, dest
);
4342 /* During loop unrolling the target of the latch edge is copied.
4343 In this case we are not looking for edge to dest, but to
4344 duplicated block whose original was dest. */
4345 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4346 if ((e
->dest
->flags
& BB_DUPLICATED
)
4347 && get_bb_original (e
->dest
) == dest
)
4350 gcc_assert (e
!= NULL
);
4353 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4355 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4357 phi_next
= PHI_CHAIN (phi
);
4358 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4359 add_phi_arg (phi_copy
, def
, e_copy
);
4364 /* Blocks in REGION_COPY array of length N_REGION were created by
4365 duplication of basic blocks. Add phi node arguments for edges
4366 going from these blocks. */
4369 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4373 for (i
= 0; i
< n_region
; i
++)
4374 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4376 for (i
= 0; i
< n_region
; i
++)
4377 add_phi_args_after_copy_bb (region_copy
[i
]);
4379 for (i
= 0; i
< n_region
; i
++)
4380 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4383 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4384 important exit edge EXIT. By important we mean that no SSA name defined
4385 inside region is live over the other exit edges of the region. All entry
4386 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4387 to the duplicate of the region. SSA form, dominance and loop information
4388 is updated. The new basic blocks are stored to REGION_COPY in the same
4389 order as they had in REGION, provided that REGION_COPY is not NULL.
4390 The function returns false if it is unable to copy the region,
4394 tree_duplicate_sese_region (edge entry
, edge exit
,
4395 basic_block
*region
, unsigned n_region
,
4396 basic_block
*region_copy
)
4399 bool free_region_copy
= false, copying_header
= false;
4400 struct loop
*loop
= entry
->dest
->loop_father
;
4404 int total_freq
= 0, entry_freq
= 0;
4405 gcov_type total_count
= 0, entry_count
= 0;
4407 if (!can_copy_bbs_p (region
, n_region
))
4410 /* Some sanity checking. Note that we do not check for all possible
4411 missuses of the functions. I.e. if you ask to copy something weird,
4412 it will work, but the state of structures probably will not be
4414 for (i
= 0; i
< n_region
; i
++)
4416 /* We do not handle subloops, i.e. all the blocks must belong to the
4418 if (region
[i
]->loop_father
!= loop
)
4421 if (region
[i
] != entry
->dest
4422 && region
[i
] == loop
->header
)
4428 /* In case the function is used for loop header copying (which is the primary
4429 use), ensure that EXIT and its copy will be new latch and entry edges. */
4430 if (loop
->header
== entry
->dest
)
4432 copying_header
= true;
4433 loop
->copy
= loop
->outer
;
4435 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4438 for (i
= 0; i
< n_region
; i
++)
4439 if (region
[i
] != exit
->src
4440 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4446 region_copy
= XNEWVEC (basic_block
, n_region
);
4447 free_region_copy
= true;
4450 gcc_assert (!need_ssa_update_p ());
4452 /* Record blocks outside the region that are dominated by something
4454 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4455 initialize_original_copy_tables ();
4457 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4459 if (entry
->dest
->count
)
4461 total_count
= entry
->dest
->count
;
4462 entry_count
= entry
->count
;
4463 /* Fix up corner cases, to avoid division by zero or creation of negative
4465 if (entry_count
> total_count
)
4466 entry_count
= total_count
;
4470 total_freq
= entry
->dest
->frequency
;
4471 entry_freq
= EDGE_FREQUENCY (entry
);
4472 /* Fix up corner cases, to avoid division by zero or creation of negative
4474 if (total_freq
== 0)
4476 else if (entry_freq
> total_freq
)
4477 entry_freq
= total_freq
;
4480 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4481 split_edge_bb_loc (entry
));
4484 scale_bbs_frequencies_gcov_type (region
, n_region
,
4485 total_count
- entry_count
,
4487 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4492 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4494 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4499 loop
->header
= exit
->dest
;
4500 loop
->latch
= exit
->src
;
4503 /* Redirect the entry and add the phi node arguments. */
4504 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4505 gcc_assert (redirected
!= NULL
);
4506 flush_pending_stmts (entry
);
4508 /* Concerning updating of dominators: We must recount dominators
4509 for entry block and its copy. Anything that is outside of the
4510 region, but was dominated by something inside needs recounting as
4512 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4513 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4514 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4517 /* Add the other PHI node arguments. */
4518 add_phi_args_after_copy (region_copy
, n_region
);
4520 /* Update the SSA web. */
4521 update_ssa (TODO_update_ssa
);
4523 if (free_region_copy
)
4526 free_original_copy_tables ();
4531 DEF_VEC_P(basic_block);
4532 DEF_VEC_ALLOC_P(basic_block,heap);
4535 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4536 adding blocks when the dominator traversal reaches EXIT. This
4537 function silently assumes that ENTRY strictly dominates EXIT. */
4540 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4541 VEC(basic_block
,heap
) **bbs_p
)
4545 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4547 son
= next_dom_son (CDI_DOMINATORS
, son
))
4549 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4551 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4561 bitmap vars_to_remove
;
4562 htab_t new_label_map
;
4566 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4567 contained in *TP and change the DECL_CONTEXT of every local
4568 variable referenced in *TP. */
4571 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4573 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4576 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t
))))
4577 TREE_BLOCK (t
) = p
->block
;
4579 if (OMP_DIRECTIVE_P (t
)
4580 && TREE_CODE (t
) != OMP_RETURN
4581 && TREE_CODE (t
) != OMP_CONTINUE
)
4583 /* Do not remap variables inside OMP directives. Variables
4584 referenced in clauses and directive header belong to the
4585 parent function and should not be moved into the child
4587 bool save_remap_decls_p
= p
->remap_decls_p
;
4588 p
->remap_decls_p
= false;
4591 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4593 p
->remap_decls_p
= save_remap_decls_p
;
4595 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4597 if (TREE_CODE (t
) == LABEL_DECL
)
4599 if (p
->new_label_map
)
4601 struct tree_map in
, *out
;
4603 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4608 DECL_CONTEXT (t
) = p
->to_context
;
4610 else if (p
->remap_decls_p
)
4612 DECL_CONTEXT (t
) = p
->to_context
;
4614 if (TREE_CODE (t
) == VAR_DECL
)
4616 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4617 f
->unexpanded_var_list
4618 = tree_cons (0, t
, f
->unexpanded_var_list
);
4620 /* Mark T to be removed from the original function,
4621 otherwise it will be given a DECL_RTL when the
4622 original function is expanded. */
4623 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4627 else if (TYPE_P (t
))
4634 /* Move basic block BB from function CFUN to function DEST_FN. The
4635 block is moved out of the original linked list and placed after
4636 block AFTER in the new list. Also, the block is removed from the
4637 original array of blocks and placed in DEST_FN's array of blocks.
4638 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4639 updated to reflect the moved edges.
4641 On exit, local variables that need to be removed from
4642 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4645 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4646 basic_block after
, bool update_edge_count_p
,
4647 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4649 struct control_flow_graph
*cfg
;
4652 block_stmt_iterator si
;
4653 struct move_stmt_d d
;
4654 unsigned old_len
, new_len
;
4657 /* Link BB to the new linked list. */
4658 move_block_after (bb
, after
);
4660 /* Update the edge count in the corresponding flowgraphs. */
4661 if (update_edge_count_p
)
4662 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4664 cfun
->cfg
->x_n_edges
--;
4665 dest_cfun
->cfg
->x_n_edges
++;
4668 /* Remove BB from the original basic block array. */
4669 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4670 cfun
->cfg
->x_n_basic_blocks
--;
4672 /* Grow DEST_CFUN's basic block array if needed. */
4673 cfg
= dest_cfun
->cfg
;
4674 cfg
->x_n_basic_blocks
++;
4675 if (bb
->index
> cfg
->x_last_basic_block
)
4676 cfg
->x_last_basic_block
= bb
->index
;
4678 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4679 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4681 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4682 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4683 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4684 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4687 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4688 cfg
->x_last_basic_block
, bb
);
4690 /* The statements in BB need to be associated with a new TREE_BLOCK.
4691 Labels need to be associated with a new label-to-block map. */
4692 memset (&d
, 0, sizeof (d
));
4693 d
.vars_to_remove
= vars_to_remove
;
4695 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4697 tree stmt
= bsi_stmt (si
);
4700 d
.from_context
= cfun
->decl
;
4701 d
.to_context
= dest_cfun
->decl
;
4702 d
.remap_decls_p
= true;
4703 d
.new_label_map
= new_label_map
;
4704 if (TREE_BLOCK (stmt
))
4705 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4707 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4709 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4711 tree label
= LABEL_EXPR_LABEL (stmt
);
4712 int uid
= LABEL_DECL_UID (label
);
4714 gcc_assert (uid
> -1);
4716 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4717 if (old_len
<= (unsigned) uid
)
4719 new_len
= 3 * uid
/ 2;
4720 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4722 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4723 memset (&addr
[old_len
], 0,
4724 sizeof (basic_block
) * (new_len
- old_len
));
4727 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4728 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4730 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4732 if (uid
>= dest_cfun
->last_label_uid
)
4733 dest_cfun
->last_label_uid
= uid
+ 1;
4735 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4736 TREE_OPERAND (stmt
, 0) =
4737 build_int_cst (NULL_TREE
,
4738 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4741 region
= lookup_stmt_eh_region (stmt
);
4744 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4745 remove_stmt_from_eh_region (stmt
);
4750 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4751 the outermost EH region. Use REGION as the incoming base EH region. */
4754 find_outermost_region_in_block (struct function
*src_cfun
,
4755 basic_block bb
, int region
)
4757 block_stmt_iterator si
;
4759 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4761 tree stmt
= bsi_stmt (si
);
4764 if (TREE_CODE (stmt
) == RESX_EXPR
)
4765 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4767 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4768 if (stmt_region
> 0)
4771 region
= stmt_region
;
4772 else if (stmt_region
!= region
)
4774 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4775 gcc_assert (region
!= -1);
4784 new_label_mapper (tree decl
, void *data
)
4786 htab_t hash
= (htab_t
) data
;
4790 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4792 m
= xmalloc (sizeof (struct tree_map
));
4793 m
->hash
= DECL_UID (decl
);
4795 m
->to
= create_artificial_label ();
4796 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4798 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4799 gcc_assert (*slot
== NULL
);
4806 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4807 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4808 single basic block in the original CFG and the new basic block is
4809 returned. DEST_CFUN must not have a CFG yet.
4811 Note that the region need not be a pure SESE region. Blocks inside
4812 the region may contain calls to abort/exit. The only restriction
4813 is that ENTRY_BB should be the only entry point and it must
4816 All local variables referenced in the region are assumed to be in
4817 the corresponding BLOCK_VARS and unexpanded variable lists
4818 associated with DEST_CFUN. */
4821 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4822 basic_block exit_bb
)
4824 VEC(basic_block
,heap
) *bbs
;
4825 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4826 struct function
*saved_cfun
;
4827 int *entry_flag
, *exit_flag
, eh_offset
;
4828 unsigned i
, num_entry_edges
, num_exit_edges
;
4831 bitmap vars_to_remove
;
4832 htab_t new_label_map
;
4836 /* Collect all the blocks in the region. Manually add ENTRY_BB
4837 because it won't be added by dfs_enumerate_from. */
4838 calculate_dominance_info (CDI_DOMINATORS
);
4840 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4842 gcc_assert (entry_bb
!= exit_bb
4844 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4847 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4848 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4850 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4851 the predecessor edges to ENTRY_BB and the successor edges to
4852 EXIT_BB so that we can re-attach them to the new basic block that
4853 will replace the region. */
4854 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4855 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4856 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4858 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4860 entry_flag
[i
] = e
->flags
;
4861 entry_pred
[i
++] = e
->src
;
4867 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4868 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4869 sizeof (basic_block
));
4870 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4872 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4874 exit_flag
[i
] = e
->flags
;
4875 exit_succ
[i
++] = e
->dest
;
4886 /* Switch context to the child function to initialize DEST_FN's CFG. */
4887 gcc_assert (dest_cfun
->cfg
== NULL
);
4890 init_empty_tree_cfg ();
4892 /* Initialize EH information for the new function. */
4894 new_label_map
= NULL
;
4899 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4900 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4902 init_eh_for_function ();
4905 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4906 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4907 new_label_map
, region
, 0);
4913 /* Move blocks from BBS into DEST_CFUN. */
4914 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4915 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4916 vars_to_remove
= BITMAP_ALLOC (NULL
);
4917 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4919 /* No need to update edge counts on the last block. It has
4920 already been updated earlier when we detached the region from
4921 the original CFG. */
4922 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4923 new_label_map
, eh_offset
);
4928 htab_delete (new_label_map
);
4930 /* Remove the variables marked in VARS_TO_REMOVE from
4931 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4932 DECL_RTL in the context of CFUN. */
4933 if (!bitmap_empty_p (vars_to_remove
))
4937 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4939 tree var
= TREE_VALUE (*p
);
4940 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4942 *p
= TREE_CHAIN (*p
);
4946 p
= &TREE_CHAIN (*p
);
4950 BITMAP_FREE (vars_to_remove
);
4952 /* Rewire the entry and exit blocks. The successor to the entry
4953 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4954 the child function. Similarly, the predecessor of DEST_FN's
4955 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4956 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4957 various CFG manipulation function get to the right CFG.
4959 FIXME, this is silly. The CFG ought to become a parameter to
4962 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4964 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4967 /* Back in the original function, the SESE region has disappeared,
4968 create a new basic block in its place. */
4969 bb
= create_empty_bb (entry_pred
[0]);
4970 for (i
= 0; i
< num_entry_edges
; i
++)
4971 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4973 for (i
= 0; i
< num_exit_edges
; i
++)
4974 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4983 free_dominance_info (CDI_DOMINATORS
);
4984 free_dominance_info (CDI_POST_DOMINATORS
);
4985 VEC_free (basic_block
, heap
, bbs
);
4991 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4994 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4996 tree arg
, vars
, var
;
4997 bool ignore_topmost_bind
= false, any_var
= false;
5000 struct function
*saved_cfun
;
5002 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5004 arg
= DECL_ARGUMENTS (fn
);
5007 print_generic_expr (file
, arg
, dump_flags
);
5008 if (TREE_CHAIN (arg
))
5009 fprintf (file
, ", ");
5010 arg
= TREE_CHAIN (arg
);
5012 fprintf (file
, ")\n");
5014 if (flags
& TDF_DETAILS
)
5015 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
5016 if (flags
& TDF_RAW
)
5018 dump_node (fn
, TDF_SLIM
| flags
, file
);
5022 /* Switch CFUN to point to FN. */
5024 cfun
= DECL_STRUCT_FUNCTION (fn
);
5026 /* When GIMPLE is lowered, the variables are no longer available in
5027 BIND_EXPRs, so display them separately. */
5028 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5030 ignore_topmost_bind
= true;
5032 fprintf (file
, "{\n");
5033 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5035 var
= TREE_VALUE (vars
);
5037 print_generic_decl (file
, var
, flags
);
5038 fprintf (file
, "\n");
5044 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5046 /* Make a CFG based dump. */
5047 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5048 if (!ignore_topmost_bind
)
5049 fprintf (file
, "{\n");
5051 if (any_var
&& n_basic_blocks
)
5052 fprintf (file
, "\n");
5055 dump_generic_bb (file
, bb
, 2, flags
);
5057 fprintf (file
, "}\n");
5058 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5064 /* Make a tree based dump. */
5065 chain
= DECL_SAVED_TREE (fn
);
5067 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5069 if (ignore_topmost_bind
)
5071 chain
= BIND_EXPR_BODY (chain
);
5079 if (!ignore_topmost_bind
)
5080 fprintf (file
, "{\n");
5085 fprintf (file
, "\n");
5087 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5088 if (ignore_topmost_bind
)
5089 fprintf (file
, "}\n");
5092 fprintf (file
, "\n\n");
5099 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5102 debug_function (tree fn
, int flags
)
5104 dump_function_to_file (fn
, stderr
, flags
);
5108 /* Pretty print of the loops intermediate representation. */
5109 static void print_loop (FILE *, struct loop
*, int);
5110 static void print_pred_bbs (FILE *, basic_block bb
);
5111 static void print_succ_bbs (FILE *, basic_block bb
);
5114 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5117 print_pred_bbs (FILE *file
, basic_block bb
)
5122 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5123 fprintf (file
, "bb_%d ", e
->src
->index
);
5127 /* Print on FILE the indexes for the successors of basic_block BB. */
5130 print_succ_bbs (FILE *file
, basic_block bb
)
5135 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5136 fprintf (file
, "bb_%d ", e
->dest
->index
);
5140 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5143 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5151 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5152 memset ((void *) s_indent
, ' ', (size_t) indent
);
5153 s_indent
[indent
] = '\0';
5155 /* Print the loop's header. */
5156 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5158 /* Print the loop's body. */
5159 fprintf (file
, "%s{\n", s_indent
);
5161 if (bb
->loop_father
== loop
)
5163 /* Print the basic_block's header. */
5164 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5165 print_pred_bbs (file
, bb
);
5166 fprintf (file
, "}, succs = {");
5167 print_succ_bbs (file
, bb
);
5168 fprintf (file
, "})\n");
5170 /* Print the basic_block's body. */
5171 fprintf (file
, "%s {\n", s_indent
);
5172 tree_dump_bb (bb
, file
, indent
+ 4);
5173 fprintf (file
, "%s }\n", s_indent
);
5176 print_loop (file
, loop
->inner
, indent
+ 2);
5177 fprintf (file
, "%s}\n", s_indent
);
5178 print_loop (file
, loop
->next
, indent
);
5182 /* Follow a CFG edge from the entry point of the program, and on entry
5183 of a loop, pretty print the loop structure on FILE. */
5186 print_loop_ir (FILE *file
)
5190 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5191 if (bb
&& bb
->loop_father
)
5192 print_loop (file
, bb
->loop_father
, 0);
5196 /* Debugging loops structure at tree level. */
5199 debug_loop_ir (void)
5201 print_loop_ir (stderr
);
5205 /* Return true if BB ends with a call, possibly followed by some
5206 instructions that must stay with the call. Return false,
5210 tree_block_ends_with_call_p (basic_block bb
)
5212 block_stmt_iterator bsi
= bsi_last (bb
);
5213 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5217 /* Return true if BB ends with a conditional branch. Return false,
5221 tree_block_ends_with_condjump_p (basic_block bb
)
5223 tree stmt
= last_stmt (bb
);
5224 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5228 /* Return true if we need to add fake edge to exit at statement T.
5229 Helper function for tree_flow_call_edges_add. */
5232 need_fake_edge_p (tree t
)
5236 /* NORETURN and LONGJMP calls already have an edge to exit.
5237 CONST and PURE calls do not need one.
5238 We don't currently check for CONST and PURE here, although
5239 it would be a good idea, because those attributes are
5240 figured out from the RTL in mark_constant_function, and
5241 the counter incrementation code from -fprofile-arcs
5242 leads to different results from -fbranch-probabilities. */
5243 call
= get_call_expr_in (t
);
5245 && !(call_expr_flags (call
) & ECF_NORETURN
))
5248 if (TREE_CODE (t
) == ASM_EXPR
5249 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5256 /* Add fake edges to the function exit for any non constant and non
5257 noreturn calls, volatile inline assembly in the bitmap of blocks
5258 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5259 the number of blocks that were split.
5261 The goal is to expose cases in which entering a basic block does
5262 not imply that all subsequent instructions must be executed. */
5265 tree_flow_call_edges_add (sbitmap blocks
)
5268 int blocks_split
= 0;
5269 int last_bb
= last_basic_block
;
5270 bool check_last_block
= false;
5272 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5276 check_last_block
= true;
5278 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5280 /* In the last basic block, before epilogue generation, there will be
5281 a fallthru edge to EXIT. Special care is required if the last insn
5282 of the last basic block is a call because make_edge folds duplicate
5283 edges, which would result in the fallthru edge also being marked
5284 fake, which would result in the fallthru edge being removed by
5285 remove_fake_edges, which would result in an invalid CFG.
5287 Moreover, we can't elide the outgoing fake edge, since the block
5288 profiler needs to take this into account in order to solve the minimal
5289 spanning tree in the case that the call doesn't return.
5291 Handle this by adding a dummy instruction in a new last basic block. */
5292 if (check_last_block
)
5294 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5295 block_stmt_iterator bsi
= bsi_last (bb
);
5297 if (!bsi_end_p (bsi
))
5300 if (t
&& need_fake_edge_p (t
))
5304 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5307 bsi_insert_on_edge (e
, build_empty_stmt ());
5308 bsi_commit_edge_inserts ();
5313 /* Now add fake edges to the function exit for any non constant
5314 calls since there is no way that we can determine if they will
5316 for (i
= 0; i
< last_bb
; i
++)
5318 basic_block bb
= BASIC_BLOCK (i
);
5319 block_stmt_iterator bsi
;
5320 tree stmt
, last_stmt
;
5325 if (blocks
&& !TEST_BIT (blocks
, i
))
5328 bsi
= bsi_last (bb
);
5329 if (!bsi_end_p (bsi
))
5331 last_stmt
= bsi_stmt (bsi
);
5334 stmt
= bsi_stmt (bsi
);
5335 if (need_fake_edge_p (stmt
))
5338 /* The handling above of the final block before the
5339 epilogue should be enough to verify that there is
5340 no edge to the exit block in CFG already.
5341 Calling make_edge in such case would cause us to
5342 mark that edge as fake and remove it later. */
5343 #ifdef ENABLE_CHECKING
5344 if (stmt
== last_stmt
)
5346 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5347 gcc_assert (e
== NULL
);
5351 /* Note that the following may create a new basic block
5352 and renumber the existing basic blocks. */
5353 if (stmt
!= last_stmt
)
5355 e
= split_block (bb
, stmt
);
5359 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5363 while (!bsi_end_p (bsi
));
5368 verify_flow_info ();
5370 return blocks_split
;
5373 /* Purge dead abnormal call edges from basic block BB. */
5376 tree_purge_dead_abnormal_call_edges (basic_block bb
)
5378 bool changed
= tree_purge_dead_eh_edges (bb
);
5380 if (current_function_has_nonlocal_label
)
5382 tree stmt
= last_stmt (bb
);
5386 if (!(stmt
&& tree_can_make_abnormal_goto (stmt
)))
5387 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5389 if (e
->flags
& EDGE_ABNORMAL
)
5398 /* See tree_purge_dead_eh_edges below. */
5400 free_dominance_info (CDI_DOMINATORS
);
5406 /* Purge dead EH edges from basic block BB. */
5409 tree_purge_dead_eh_edges (basic_block bb
)
5411 bool changed
= false;
5414 tree stmt
= last_stmt (bb
);
5416 if (stmt
&& tree_can_throw_internal (stmt
))
5419 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5421 if (e
->flags
& EDGE_EH
)
5430 /* Removal of dead EH edges might change dominators of not
5431 just immediate successors. E.g. when bb1 is changed so that
5432 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5433 eh edges purged by this function in:
5445 idom(bb5) must be recomputed. For now just free the dominance
5448 free_dominance_info (CDI_DOMINATORS
);
5454 tree_purge_all_dead_eh_edges (bitmap blocks
)
5456 bool changed
= false;
5460 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5462 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5468 /* This function is called whenever a new edge is created or
5472 tree_execute_on_growing_pred (edge e
)
5474 basic_block bb
= e
->dest
;
5477 reserve_phi_args_for_new_edge (bb
);
5480 /* This function is called immediately before edge E is removed from
5481 the edge vector E->dest->preds. */
5484 tree_execute_on_shrinking_pred (edge e
)
5486 if (phi_nodes (e
->dest
))
5487 remove_phi_args (e
);
5490 /*---------------------------------------------------------------------------
5491 Helper functions for Loop versioning
5492 ---------------------------------------------------------------------------*/
5494 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5495 of 'first'. Both of them are dominated by 'new_head' basic block. When
5496 'new_head' was created by 'second's incoming edge it received phi arguments
5497 on the edge by split_edge(). Later, additional edge 'e' was created to
5498 connect 'new_head' and 'first'. Now this routine adds phi args on this
5499 additional edge 'e' that new_head to second edge received as part of edge
5504 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5505 basic_block new_head
, edge e
)
5508 edge e2
= find_edge (new_head
, second
);
5510 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5511 edge, we should always have an edge from NEW_HEAD to SECOND. */
5512 gcc_assert (e2
!= NULL
);
5514 /* Browse all 'second' basic block phi nodes and add phi args to
5515 edge 'e' for 'first' head. PHI args are always in correct order. */
5517 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5519 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5521 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5522 add_phi_arg (phi1
, def
, e
);
5526 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5527 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5528 the destination of the ELSE part. */
5530 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5531 basic_block cond_bb
, void *cond_e
)
5533 block_stmt_iterator bsi
;
5534 tree goto1
= NULL_TREE
;
5535 tree goto2
= NULL_TREE
;
5536 tree new_cond_expr
= NULL_TREE
;
5537 tree cond_expr
= (tree
) cond_e
;
5540 /* Build new conditional expr */
5541 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5542 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5543 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5545 /* Add new cond in cond_bb. */
5546 bsi
= bsi_start (cond_bb
);
5547 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5548 /* Adjust edges appropriately to connect new head with first head
5549 as well as second head. */
5550 e0
= single_succ_edge (cond_bb
);
5551 e0
->flags
&= ~EDGE_FALLTHRU
;
5552 e0
->flags
|= EDGE_FALSE_VALUE
;
5555 struct cfg_hooks tree_cfg_hooks
= {
5557 tree_verify_flow_info
,
5558 tree_dump_bb
, /* dump_bb */
5559 create_bb
, /* create_basic_block */
5560 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5561 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5562 remove_bb
, /* delete_basic_block */
5563 tree_split_block
, /* split_block */
5564 tree_move_block_after
, /* move_block_after */
5565 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5566 tree_merge_blocks
, /* merge_blocks */
5567 tree_predict_edge
, /* predict_edge */
5568 tree_predicted_by_p
, /* predicted_by_p */
5569 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5570 tree_duplicate_bb
, /* duplicate_block */
5571 tree_split_edge
, /* split_edge */
5572 tree_make_forwarder_block
, /* make_forward_block */
5573 NULL
, /* tidy_fallthru_edge */
5574 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5575 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5576 tree_flow_call_edges_add
, /* flow_call_edges_add */
5577 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5578 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5579 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5580 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5581 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5582 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5583 flush_pending_stmts
/* flush_pending_stmts */
5587 /* Split all critical edges. */
5590 split_critical_edges (void)
5596 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5597 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5598 mappings around the calls to split_edge. */
5599 start_recording_case_labels ();
5602 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5603 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5608 end_recording_case_labels ();
5612 struct tree_opt_pass pass_split_crit_edges
=
5614 "crited", /* name */
5616 split_critical_edges
, /* execute */
5619 0, /* static_pass_number */
5620 TV_TREE_SPLIT_EDGES
, /* tv_id */
5621 PROP_cfg
, /* properties required */
5622 PROP_no_crit_edges
, /* properties_provided */
5623 0, /* properties_destroyed */
5624 0, /* todo_flags_start */
5625 TODO_dump_func
, /* todo_flags_finish */
5630 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5631 a temporary, make sure and register it to be renamed if necessary,
5632 and finally return the temporary. Put the statements to compute
5633 EXP before the current statement in BSI. */
5636 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5638 tree t
, new_stmt
, orig_stmt
;
5640 if (is_gimple_val (exp
))
5643 t
= make_rename_temp (type
, NULL
);
5644 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5646 orig_stmt
= bsi_stmt (*bsi
);
5647 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5648 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5650 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5652 mark_new_vars_to_rename (new_stmt
);
5657 /* Build a ternary operation and gimplify it. Emit code before BSI.
5658 Return the gimple_val holding the result. */
5661 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5662 tree type
, tree a
, tree b
, tree c
)
5666 ret
= fold_build3 (code
, type
, a
, b
, c
);
5669 return gimplify_val (bsi
, type
, ret
);
5672 /* Build a binary operation and gimplify it. Emit code before BSI.
5673 Return the gimple_val holding the result. */
5676 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5677 tree type
, tree a
, tree b
)
5681 ret
= fold_build2 (code
, type
, a
, b
);
5684 return gimplify_val (bsi
, type
, ret
);
5687 /* Build a unary operation and gimplify it. Emit code before BSI.
5688 Return the gimple_val holding the result. */
5691 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5696 ret
= fold_build1 (code
, type
, a
);
5699 return gimplify_val (bsi
, type
, ret
);
5704 /* Emit return warnings. */
5707 execute_warn_function_return (void)
5709 #ifdef USE_MAPPED_LOCATION
5710 source_location location
;
5718 /* If we have a path to EXIT, then we do return. */
5719 if (TREE_THIS_VOLATILE (cfun
->decl
)
5720 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5722 #ifdef USE_MAPPED_LOCATION
5723 location
= UNKNOWN_LOCATION
;
5727 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5729 last
= last_stmt (e
->src
);
5730 if (TREE_CODE (last
) == RETURN_EXPR
5731 #ifdef USE_MAPPED_LOCATION
5732 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5734 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5738 #ifdef USE_MAPPED_LOCATION
5739 if (location
== UNKNOWN_LOCATION
)
5740 location
= cfun
->function_end_locus
;
5741 warning (0, "%H%<noreturn%> function does return", &location
);
5744 locus
= &cfun
->function_end_locus
;
5745 warning (0, "%H%<noreturn%> function does return", locus
);
5749 /* If we see "return;" in some basic block, then we do reach the end
5750 without returning a value. */
5751 else if (warn_return_type
5752 && !TREE_NO_WARNING (cfun
->decl
)
5753 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5754 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5756 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5758 tree last
= last_stmt (e
->src
);
5759 if (TREE_CODE (last
) == RETURN_EXPR
5760 && TREE_OPERAND (last
, 0) == NULL
5761 && !TREE_NO_WARNING (last
))
5763 #ifdef USE_MAPPED_LOCATION
5764 location
= EXPR_LOCATION (last
);
5765 if (location
== UNKNOWN_LOCATION
)
5766 location
= cfun
->function_end_locus
;
5767 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5769 locus
= EXPR_LOCUS (last
);
5771 locus
= &cfun
->function_end_locus
;
5772 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5774 TREE_NO_WARNING (cfun
->decl
) = 1;
5783 /* Given a basic block B which ends with a conditional and has
5784 precisely two successors, determine which of the edges is taken if
5785 the conditional is true and which is taken if the conditional is
5786 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5789 extract_true_false_edges_from_block (basic_block b
,
5793 edge e
= EDGE_SUCC (b
, 0);
5795 if (e
->flags
& EDGE_TRUE_VALUE
)
5798 *false_edge
= EDGE_SUCC (b
, 1);
5803 *true_edge
= EDGE_SUCC (b
, 1);
5807 struct tree_opt_pass pass_warn_function_return
=
5811 execute_warn_function_return
, /* execute */
5814 0, /* static_pass_number */
5816 PROP_cfg
, /* properties_required */
5817 0, /* properties_provided */
5818 0, /* properties_destroyed */
5819 0, /* todo_flags_start */
5820 0, /* todo_flags_finish */
5824 /* Emit noreturn warnings. */
5827 execute_warn_function_noreturn (void)
5829 if (warn_missing_noreturn
5830 && !TREE_THIS_VOLATILE (cfun
->decl
)
5831 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5832 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5833 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5834 "for attribute %<noreturn%>",
5839 struct tree_opt_pass pass_warn_function_noreturn
=
5843 execute_warn_function_noreturn
, /* execute */
5846 0, /* static_pass_number */
5848 PROP_cfg
, /* properties_required */
5849 0, /* properties_provided */
5850 0, /* properties_destroyed */
5851 0, /* todo_flags_start */
5852 0, /* todo_flags_finish */