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
:
3333 case FIX_FLOOR_EXPR
:
3334 case FIX_ROUND_EXPR
:
3339 case NON_LVALUE_EXPR
:
3340 case TRUTH_NOT_EXPR
:
3341 CHECK_OP (0, "invalid operand to unary operator");
3348 case ARRAY_RANGE_REF
:
3350 case VIEW_CONVERT_EXPR
:
3351 /* We have a nest of references. Verify that each of the operands
3352 that determine where to reference is either a constant or a variable,
3353 verify that the base is valid, and then show we've already checked
3355 while (handled_component_p (t
))
3357 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3358 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3359 else if (TREE_CODE (t
) == ARRAY_REF
3360 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3362 CHECK_OP (1, "invalid array index");
3363 if (TREE_OPERAND (t
, 2))
3364 CHECK_OP (2, "invalid array lower bound");
3365 if (TREE_OPERAND (t
, 3))
3366 CHECK_OP (3, "invalid array stride");
3368 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3370 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3371 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3374 t
= TREE_OPERAND (t
, 0);
3377 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3379 error ("invalid reference prefix");
3391 case UNORDERED_EXPR
:
3402 case TRUNC_DIV_EXPR
:
3404 case FLOOR_DIV_EXPR
:
3405 case ROUND_DIV_EXPR
:
3406 case TRUNC_MOD_EXPR
:
3408 case FLOOR_MOD_EXPR
:
3409 case ROUND_MOD_EXPR
:
3411 case EXACT_DIV_EXPR
:
3421 CHECK_OP (0, "invalid operand to binary operator");
3422 CHECK_OP (1, "invalid operand to binary operator");
3434 /* Verify STMT, return true if STMT is not in GIMPLE form.
3435 TODO: Implement type checking. */
3438 verify_stmt (tree stmt
, bool last_in_block
)
3442 if (OMP_DIRECTIVE_P (stmt
))
3444 /* OpenMP directives are validated by the FE and never operated
3445 on by the optimizers. Furthermore, OMP_FOR may contain
3446 non-gimple expressions when the main index variable has had
3447 its address taken. This does not affect the loop itself
3448 because the header of an OMP_FOR is merely used to determine
3449 how to setup the parallel iteration. */
3453 if (!is_gimple_stmt (stmt
))
3455 error ("is not a valid GIMPLE statement");
3459 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3462 debug_generic_stmt (addr
);
3466 /* If the statement is marked as part of an EH region, then it is
3467 expected that the statement could throw. Verify that when we
3468 have optimizations that simplify statements such that we prove
3469 that they cannot throw, that we update other data structures
3471 if (lookup_stmt_eh_region (stmt
) >= 0)
3473 if (!tree_could_throw_p (stmt
))
3475 error ("statement marked for throw, but doesn%'t");
3478 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3480 error ("statement marked for throw in middle of block");
3488 debug_generic_stmt (stmt
);
3493 /* Return true when the T can be shared. */
3496 tree_node_can_be_shared (tree t
)
3498 if (IS_TYPE_OR_DECL_P (t
)
3499 || is_gimple_min_invariant (t
)
3500 || TREE_CODE (t
) == SSA_NAME
3501 || t
== error_mark_node
3502 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3505 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3508 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3509 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3510 || TREE_CODE (t
) == COMPONENT_REF
3511 || TREE_CODE (t
) == REALPART_EXPR
3512 || TREE_CODE (t
) == IMAGPART_EXPR
)
3513 t
= TREE_OPERAND (t
, 0);
3522 /* Called via walk_trees. Verify tree sharing. */
3525 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3527 htab_t htab
= (htab_t
) data
;
3530 if (tree_node_can_be_shared (*tp
))
3532 *walk_subtrees
= false;
3536 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3538 return (tree
) *slot
;
3545 /* Verify the GIMPLE statement chain. */
3551 block_stmt_iterator bsi
;
3556 timevar_push (TV_TREE_STMT_VERIFY
);
3557 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3564 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3566 int phi_num_args
= PHI_NUM_ARGS (phi
);
3568 if (bb_for_stmt (phi
) != bb
)
3570 error ("bb_for_stmt (phi) is set to a wrong basic block");
3574 for (i
= 0; i
< phi_num_args
; i
++)
3576 tree t
= PHI_ARG_DEF (phi
, i
);
3579 /* Addressable variables do have SSA_NAMEs but they
3580 are not considered gimple values. */
3581 if (TREE_CODE (t
) != SSA_NAME
3582 && TREE_CODE (t
) != FUNCTION_DECL
3583 && !is_gimple_val (t
))
3585 error ("PHI def is not a GIMPLE value");
3586 debug_generic_stmt (phi
);
3587 debug_generic_stmt (t
);
3591 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3594 debug_generic_stmt (addr
);
3598 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3601 error ("incorrect sharing of tree nodes");
3602 debug_generic_stmt (phi
);
3603 debug_generic_stmt (addr
);
3609 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3611 tree stmt
= bsi_stmt (bsi
);
3613 if (bb_for_stmt (stmt
) != bb
)
3615 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3620 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3621 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3624 error ("incorrect sharing of tree nodes");
3625 debug_generic_stmt (stmt
);
3626 debug_generic_stmt (addr
);
3633 internal_error ("verify_stmts failed");
3636 timevar_pop (TV_TREE_STMT_VERIFY
);
3640 /* Verifies that the flow information is OK. */
3643 tree_verify_flow_info (void)
3647 block_stmt_iterator bsi
;
3652 if (ENTRY_BLOCK_PTR
->stmt_list
)
3654 error ("ENTRY_BLOCK has a statement list associated with it");
3658 if (EXIT_BLOCK_PTR
->stmt_list
)
3660 error ("EXIT_BLOCK has a statement list associated with it");
3664 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3665 if (e
->flags
& EDGE_FALLTHRU
)
3667 error ("fallthru to exit from bb %d", e
->src
->index
);
3673 bool found_ctrl_stmt
= false;
3677 /* Skip labels on the start of basic block. */
3678 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3680 tree prev_stmt
= stmt
;
3682 stmt
= bsi_stmt (bsi
);
3684 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3687 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3689 error ("nonlocal label ");
3690 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3691 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3696 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3699 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3700 fprintf (stderr
, " to block does not match in bb %d",
3705 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3706 != current_function_decl
)
3709 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3710 fprintf (stderr
, " has incorrect context in bb %d",
3716 /* Verify that body of basic block BB is free of control flow. */
3717 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3719 tree stmt
= bsi_stmt (bsi
);
3721 if (found_ctrl_stmt
)
3723 error ("control flow in the middle of basic block %d",
3728 if (stmt_ends_bb_p (stmt
))
3729 found_ctrl_stmt
= true;
3731 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3734 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3735 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3740 bsi
= bsi_last (bb
);
3741 if (bsi_end_p (bsi
))
3744 stmt
= bsi_stmt (bsi
);
3746 err
|= verify_eh_edges (stmt
);
3748 if (is_ctrl_stmt (stmt
))
3750 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3751 if (e
->flags
& EDGE_FALLTHRU
)
3753 error ("fallthru edge after a control statement in bb %d",
3759 if (TREE_CODE (stmt
) != COND_EXPR
)
3761 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3762 after anything else but if statement. */
3763 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3764 if (e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
))
3766 error ("true/false edge after a non-COND_EXPR in bb %d",
3772 switch (TREE_CODE (stmt
))
3778 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3779 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3781 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3785 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3787 if (!true_edge
|| !false_edge
3788 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3789 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3790 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3791 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3792 || EDGE_COUNT (bb
->succs
) >= 3)
3794 error ("wrong outgoing edge flags at end of bb %d",
3799 if (!has_label_p (true_edge
->dest
,
3800 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3802 error ("%<then%> label does not match edge at end of bb %d",
3807 if (!has_label_p (false_edge
->dest
,
3808 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3810 error ("%<else%> label does not match edge at end of bb %d",
3818 if (simple_goto_p (stmt
))
3820 error ("explicit goto at end of bb %d", bb
->index
);
3825 /* FIXME. We should double check that the labels in the
3826 destination blocks have their address taken. */
3827 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3828 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3829 | EDGE_FALSE_VALUE
))
3830 || !(e
->flags
& EDGE_ABNORMAL
))
3832 error ("wrong outgoing edge flags at end of bb %d",
3840 if (!single_succ_p (bb
)
3841 || (single_succ_edge (bb
)->flags
3842 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3843 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3845 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3848 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3850 error ("return edge does not point to exit in bb %d",
3863 vec
= SWITCH_LABELS (stmt
);
3864 n
= TREE_VEC_LENGTH (vec
);
3866 /* Mark all the destination basic blocks. */
3867 for (i
= 0; i
< n
; ++i
)
3869 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3870 basic_block label_bb
= label_to_block (lab
);
3872 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3873 label_bb
->aux
= (void *)1;
3876 /* Verify that the case labels are sorted. */
3877 prev
= TREE_VEC_ELT (vec
, 0);
3878 for (i
= 1; i
< n
- 1; ++i
)
3880 tree c
= TREE_VEC_ELT (vec
, i
);
3883 error ("found default case not at end of case vector");
3887 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3889 error ("case labels not sorted: ");
3890 print_generic_expr (stderr
, prev
, 0);
3891 fprintf (stderr
," is greater than ");
3892 print_generic_expr (stderr
, c
, 0);
3893 fprintf (stderr
," but comes before it.\n");
3898 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3900 error ("no default case found at end of case vector");
3904 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3908 error ("extra outgoing edge %d->%d",
3909 bb
->index
, e
->dest
->index
);
3912 e
->dest
->aux
= (void *)2;
3913 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3914 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3916 error ("wrong outgoing edge flags at end of bb %d",
3922 /* Check that we have all of them. */
3923 for (i
= 0; i
< n
; ++i
)
3925 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3926 basic_block label_bb
= label_to_block (lab
);
3928 if (label_bb
->aux
!= (void *)2)
3930 error ("missing edge %i->%i",
3931 bb
->index
, label_bb
->index
);
3936 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3937 e
->dest
->aux
= (void *)0;
3944 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3945 verify_dominators (CDI_DOMINATORS
);
3951 /* Updates phi nodes after creating a forwarder block joined
3952 by edge FALLTHRU. */
3955 tree_make_forwarder_block (edge fallthru
)
3959 basic_block dummy
, bb
;
3960 tree phi
, new_phi
, var
;
3962 dummy
= fallthru
->src
;
3963 bb
= fallthru
->dest
;
3965 if (single_pred_p (bb
))
3968 /* If we redirected a branch we must create new phi nodes at the
3970 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3972 var
= PHI_RESULT (phi
);
3973 new_phi
= create_phi_node (var
, bb
);
3974 SSA_NAME_DEF_STMT (var
) = new_phi
;
3975 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3976 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3979 /* Ensure that the PHI node chain is in the same order. */
3980 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3982 /* Add the arguments we have stored on edges. */
3983 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3988 flush_pending_stmts (e
);
3993 /* Return a non-special label in the head of basic block BLOCK.
3994 Create one if it doesn't exist. */
3997 tree_block_label (basic_block bb
)
3999 block_stmt_iterator i
, s
= bsi_start (bb
);
4003 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4005 stmt
= bsi_stmt (i
);
4006 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4008 label
= LABEL_EXPR_LABEL (stmt
);
4009 if (!DECL_NONLOCAL (label
))
4012 bsi_move_before (&i
, &s
);
4017 label
= create_artificial_label ();
4018 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4019 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4024 /* Attempt to perform edge redirection by replacing a possibly complex
4025 jump instruction by a goto or by removing the jump completely.
4026 This can apply only if all edges now point to the same block. The
4027 parameters and return values are equivalent to
4028 redirect_edge_and_branch. */
4031 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4033 basic_block src
= e
->src
;
4034 block_stmt_iterator b
;
4037 /* We can replace or remove a complex jump only when we have exactly
4039 if (EDGE_COUNT (src
->succs
) != 2
4040 /* Verify that all targets will be TARGET. Specifically, the
4041 edge that is not E must also go to TARGET. */
4042 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4048 stmt
= bsi_stmt (b
);
4050 if (TREE_CODE (stmt
) == COND_EXPR
4051 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4053 bsi_remove (&b
, true);
4054 e
= ssa_redirect_edge (e
, target
);
4055 e
->flags
= EDGE_FALLTHRU
;
4063 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4064 edge representing the redirected branch. */
4067 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4069 basic_block bb
= e
->src
;
4070 block_stmt_iterator bsi
;
4074 if (e
->flags
& EDGE_ABNORMAL
)
4077 if (e
->src
!= ENTRY_BLOCK_PTR
4078 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4081 if (e
->dest
== dest
)
4084 label
= tree_block_label (dest
);
4086 bsi
= bsi_last (bb
);
4087 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4089 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4092 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4093 ? COND_EXPR_THEN (stmt
)
4094 : COND_EXPR_ELSE (stmt
));
4095 GOTO_DESTINATION (stmt
) = label
;
4099 /* No non-abnormal edges should lead from a non-simple goto, and
4100 simple ones should be represented implicitly. */
4105 tree cases
= get_cases_for_edge (e
, stmt
);
4107 /* If we have a list of cases associated with E, then use it
4108 as it's a lot faster than walking the entire case vector. */
4111 edge e2
= find_edge (e
->src
, dest
);
4118 CASE_LABEL (cases
) = label
;
4119 cases
= TREE_CHAIN (cases
);
4122 /* If there was already an edge in the CFG, then we need
4123 to move all the cases associated with E to E2. */
4126 tree cases2
= get_cases_for_edge (e2
, stmt
);
4128 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4129 TREE_CHAIN (cases2
) = first
;
4134 tree vec
= SWITCH_LABELS (stmt
);
4135 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4137 for (i
= 0; i
< n
; i
++)
4139 tree elt
= TREE_VEC_ELT (vec
, i
);
4141 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4142 CASE_LABEL (elt
) = label
;
4150 bsi_remove (&bsi
, true);
4151 e
->flags
|= EDGE_FALLTHRU
;
4155 /* Otherwise it must be a fallthru edge, and we don't need to
4156 do anything besides redirecting it. */
4157 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4161 /* Update/insert PHI nodes as necessary. */
4163 /* Now update the edges in the CFG. */
4164 e
= ssa_redirect_edge (e
, dest
);
4170 /* Simple wrapper, as we can always redirect fallthru edges. */
4173 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4175 e
= tree_redirect_edge_and_branch (e
, dest
);
4182 /* Splits basic block BB after statement STMT (but at least after the
4183 labels). If STMT is NULL, BB is split just after the labels. */
4186 tree_split_block (basic_block bb
, void *stmt
)
4188 block_stmt_iterator bsi
;
4189 tree_stmt_iterator tsi_tgt
;
4195 new_bb
= create_empty_bb (bb
);
4197 /* Redirect the outgoing edges. */
4198 new_bb
->succs
= bb
->succs
;
4200 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4203 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4206 /* Move everything from BSI to the new basic block. */
4207 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4209 act
= bsi_stmt (bsi
);
4210 if (TREE_CODE (act
) == LABEL_EXPR
)
4223 if (bsi_end_p (bsi
))
4226 /* Split the statement list - avoid re-creating new containers as this
4227 brings ugly quadratic memory consumption in the inliner.
4228 (We are still quadratic since we need to update stmt BB pointers,
4230 new_bb
->stmt_list
= tsi_split_statement_list_before (&bsi
.tsi
);
4231 for (tsi_tgt
= tsi_start (new_bb
->stmt_list
);
4232 !tsi_end_p (tsi_tgt
); tsi_next (&tsi_tgt
))
4233 change_bb_for_stmt (tsi_stmt (tsi_tgt
), new_bb
);
4239 /* Moves basic block BB after block AFTER. */
4242 tree_move_block_after (basic_block bb
, basic_block after
)
4244 if (bb
->prev_bb
== after
)
4248 link_block (bb
, after
);
4254 /* Return true if basic_block can be duplicated. */
4257 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4263 /* Create a duplicate of the basic block BB. NOTE: This does not
4264 preserve SSA form. */
4267 tree_duplicate_bb (basic_block bb
)
4270 block_stmt_iterator bsi
, bsi_tgt
;
4273 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4275 /* Copy the PHI nodes. We ignore PHI node arguments here because
4276 the incoming edges have not been setup yet. */
4277 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4279 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4280 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4283 /* Keep the chain of PHI nodes in the same order so that they can be
4284 updated by ssa_redirect_edge. */
4285 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4287 bsi_tgt
= bsi_start (new_bb
);
4288 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4290 def_operand_p def_p
;
4291 ssa_op_iter op_iter
;
4295 stmt
= bsi_stmt (bsi
);
4296 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4299 /* Create a new copy of STMT and duplicate STMT's virtual
4301 copy
= unshare_expr (stmt
);
4302 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4303 copy_virtual_operands (copy
, stmt
);
4304 region
= lookup_stmt_eh_region (stmt
);
4306 add_stmt_to_eh_region (copy
, region
);
4308 /* Create new names for all the definitions created by COPY and
4309 add replacement mappings for each new name. */
4310 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4311 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4318 /* Basic block BB_COPY was created by code duplication. Add phi node
4319 arguments for edges going out of BB_COPY. The blocks that were
4320 duplicated have BB_DUPLICATED set. */
4323 add_phi_args_after_copy_bb (basic_block bb_copy
)
4325 basic_block bb
, dest
;
4328 tree phi
, phi_copy
, phi_next
, def
;
4330 bb
= get_bb_original (bb_copy
);
4332 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4334 if (!phi_nodes (e_copy
->dest
))
4337 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4338 dest
= get_bb_original (e_copy
->dest
);
4340 dest
= e_copy
->dest
;
4342 e
= find_edge (bb
, dest
);
4345 /* During loop unrolling the target of the latch edge is copied.
4346 In this case we are not looking for edge to dest, but to
4347 duplicated block whose original was dest. */
4348 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4349 if ((e
->dest
->flags
& BB_DUPLICATED
)
4350 && get_bb_original (e
->dest
) == dest
)
4353 gcc_assert (e
!= NULL
);
4356 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4358 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4360 phi_next
= PHI_CHAIN (phi
);
4361 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4362 add_phi_arg (phi_copy
, def
, e_copy
);
4367 /* Blocks in REGION_COPY array of length N_REGION were created by
4368 duplication of basic blocks. Add phi node arguments for edges
4369 going from these blocks. */
4372 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4376 for (i
= 0; i
< n_region
; i
++)
4377 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4379 for (i
= 0; i
< n_region
; i
++)
4380 add_phi_args_after_copy_bb (region_copy
[i
]);
4382 for (i
= 0; i
< n_region
; i
++)
4383 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4386 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4387 important exit edge EXIT. By important we mean that no SSA name defined
4388 inside region is live over the other exit edges of the region. All entry
4389 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4390 to the duplicate of the region. SSA form, dominance and loop information
4391 is updated. The new basic blocks are stored to REGION_COPY in the same
4392 order as they had in REGION, provided that REGION_COPY is not NULL.
4393 The function returns false if it is unable to copy the region,
4397 tree_duplicate_sese_region (edge entry
, edge exit
,
4398 basic_block
*region
, unsigned n_region
,
4399 basic_block
*region_copy
)
4402 bool free_region_copy
= false, copying_header
= false;
4403 struct loop
*loop
= entry
->dest
->loop_father
;
4407 int total_freq
= 0, entry_freq
= 0;
4408 gcov_type total_count
= 0, entry_count
= 0;
4410 if (!can_copy_bbs_p (region
, n_region
))
4413 /* Some sanity checking. Note that we do not check for all possible
4414 missuses of the functions. I.e. if you ask to copy something weird,
4415 it will work, but the state of structures probably will not be
4417 for (i
= 0; i
< n_region
; i
++)
4419 /* We do not handle subloops, i.e. all the blocks must belong to the
4421 if (region
[i
]->loop_father
!= loop
)
4424 if (region
[i
] != entry
->dest
4425 && region
[i
] == loop
->header
)
4431 /* In case the function is used for loop header copying (which is the primary
4432 use), ensure that EXIT and its copy will be new latch and entry edges. */
4433 if (loop
->header
== entry
->dest
)
4435 copying_header
= true;
4436 loop
->copy
= loop
->outer
;
4438 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4441 for (i
= 0; i
< n_region
; i
++)
4442 if (region
[i
] != exit
->src
4443 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4449 region_copy
= XNEWVEC (basic_block
, n_region
);
4450 free_region_copy
= true;
4453 gcc_assert (!need_ssa_update_p ());
4455 /* Record blocks outside the region that are dominated by something
4457 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4458 initialize_original_copy_tables ();
4460 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4462 if (entry
->dest
->count
)
4464 total_count
= entry
->dest
->count
;
4465 entry_count
= entry
->count
;
4466 /* Fix up corner cases, to avoid division by zero or creation of negative
4468 if (entry_count
> total_count
)
4469 entry_count
= total_count
;
4473 total_freq
= entry
->dest
->frequency
;
4474 entry_freq
= EDGE_FREQUENCY (entry
);
4475 /* Fix up corner cases, to avoid division by zero or creation of negative
4477 if (total_freq
== 0)
4479 else if (entry_freq
> total_freq
)
4480 entry_freq
= total_freq
;
4483 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4484 split_edge_bb_loc (entry
));
4487 scale_bbs_frequencies_gcov_type (region
, n_region
,
4488 total_count
- entry_count
,
4490 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4495 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4497 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4502 loop
->header
= exit
->dest
;
4503 loop
->latch
= exit
->src
;
4506 /* Redirect the entry and add the phi node arguments. */
4507 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4508 gcc_assert (redirected
!= NULL
);
4509 flush_pending_stmts (entry
);
4511 /* Concerning updating of dominators: We must recount dominators
4512 for entry block and its copy. Anything that is outside of the
4513 region, but was dominated by something inside needs recounting as
4515 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4516 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4517 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4520 /* Add the other PHI node arguments. */
4521 add_phi_args_after_copy (region_copy
, n_region
);
4523 /* Update the SSA web. */
4524 update_ssa (TODO_update_ssa
);
4526 if (free_region_copy
)
4529 free_original_copy_tables ();
4534 DEF_VEC_P(basic_block);
4535 DEF_VEC_ALLOC_P(basic_block,heap);
4538 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4539 adding blocks when the dominator traversal reaches EXIT. This
4540 function silently assumes that ENTRY strictly dominates EXIT. */
4543 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4544 VEC(basic_block
,heap
) **bbs_p
)
4548 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4550 son
= next_dom_son (CDI_DOMINATORS
, son
))
4552 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4554 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4564 bitmap vars_to_remove
;
4565 htab_t new_label_map
;
4569 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4570 contained in *TP and change the DECL_CONTEXT of every local
4571 variable referenced in *TP. */
4574 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4576 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4579 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t
))))
4580 TREE_BLOCK (t
) = p
->block
;
4582 if (OMP_DIRECTIVE_P (t
)
4583 && TREE_CODE (t
) != OMP_RETURN
4584 && TREE_CODE (t
) != OMP_CONTINUE
)
4586 /* Do not remap variables inside OMP directives. Variables
4587 referenced in clauses and directive header belong to the
4588 parent function and should not be moved into the child
4590 bool save_remap_decls_p
= p
->remap_decls_p
;
4591 p
->remap_decls_p
= false;
4594 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4596 p
->remap_decls_p
= save_remap_decls_p
;
4598 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4600 if (TREE_CODE (t
) == LABEL_DECL
)
4602 if (p
->new_label_map
)
4604 struct tree_map in
, *out
;
4606 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4611 DECL_CONTEXT (t
) = p
->to_context
;
4613 else if (p
->remap_decls_p
)
4615 DECL_CONTEXT (t
) = p
->to_context
;
4617 if (TREE_CODE (t
) == VAR_DECL
)
4619 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4620 f
->unexpanded_var_list
4621 = tree_cons (0, t
, f
->unexpanded_var_list
);
4623 /* Mark T to be removed from the original function,
4624 otherwise it will be given a DECL_RTL when the
4625 original function is expanded. */
4626 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4630 else if (TYPE_P (t
))
4637 /* Move basic block BB from function CFUN to function DEST_FN. The
4638 block is moved out of the original linked list and placed after
4639 block AFTER in the new list. Also, the block is removed from the
4640 original array of blocks and placed in DEST_FN's array of blocks.
4641 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4642 updated to reflect the moved edges.
4644 On exit, local variables that need to be removed from
4645 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4648 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4649 basic_block after
, bool update_edge_count_p
,
4650 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4652 struct control_flow_graph
*cfg
;
4655 block_stmt_iterator si
;
4656 struct move_stmt_d d
;
4657 unsigned old_len
, new_len
;
4660 /* Link BB to the new linked list. */
4661 move_block_after (bb
, after
);
4663 /* Update the edge count in the corresponding flowgraphs. */
4664 if (update_edge_count_p
)
4665 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4667 cfun
->cfg
->x_n_edges
--;
4668 dest_cfun
->cfg
->x_n_edges
++;
4671 /* Remove BB from the original basic block array. */
4672 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4673 cfun
->cfg
->x_n_basic_blocks
--;
4675 /* Grow DEST_CFUN's basic block array if needed. */
4676 cfg
= dest_cfun
->cfg
;
4677 cfg
->x_n_basic_blocks
++;
4678 if (bb
->index
> cfg
->x_last_basic_block
)
4679 cfg
->x_last_basic_block
= bb
->index
;
4681 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4682 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4684 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4685 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4686 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4687 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4690 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4691 cfg
->x_last_basic_block
, bb
);
4693 /* The statements in BB need to be associated with a new TREE_BLOCK.
4694 Labels need to be associated with a new label-to-block map. */
4695 memset (&d
, 0, sizeof (d
));
4696 d
.vars_to_remove
= vars_to_remove
;
4698 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4700 tree stmt
= bsi_stmt (si
);
4703 d
.from_context
= cfun
->decl
;
4704 d
.to_context
= dest_cfun
->decl
;
4705 d
.remap_decls_p
= true;
4706 d
.new_label_map
= new_label_map
;
4707 if (TREE_BLOCK (stmt
))
4708 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4710 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4712 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4714 tree label
= LABEL_EXPR_LABEL (stmt
);
4715 int uid
= LABEL_DECL_UID (label
);
4717 gcc_assert (uid
> -1);
4719 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4720 if (old_len
<= (unsigned) uid
)
4722 new_len
= 3 * uid
/ 2;
4723 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4725 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4726 memset (&addr
[old_len
], 0,
4727 sizeof (basic_block
) * (new_len
- old_len
));
4730 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4731 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4733 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4735 if (uid
>= dest_cfun
->last_label_uid
)
4736 dest_cfun
->last_label_uid
= uid
+ 1;
4738 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4739 TREE_OPERAND (stmt
, 0) =
4740 build_int_cst (NULL_TREE
,
4741 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4744 region
= lookup_stmt_eh_region (stmt
);
4747 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4748 remove_stmt_from_eh_region (stmt
);
4753 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4754 the outermost EH region. Use REGION as the incoming base EH region. */
4757 find_outermost_region_in_block (struct function
*src_cfun
,
4758 basic_block bb
, int region
)
4760 block_stmt_iterator si
;
4762 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4764 tree stmt
= bsi_stmt (si
);
4767 if (TREE_CODE (stmt
) == RESX_EXPR
)
4768 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4770 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4771 if (stmt_region
> 0)
4774 region
= stmt_region
;
4775 else if (stmt_region
!= region
)
4777 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4778 gcc_assert (region
!= -1);
4787 new_label_mapper (tree decl
, void *data
)
4789 htab_t hash
= (htab_t
) data
;
4793 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4795 m
= xmalloc (sizeof (struct tree_map
));
4796 m
->hash
= DECL_UID (decl
);
4798 m
->to
= create_artificial_label ();
4799 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4801 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4802 gcc_assert (*slot
== NULL
);
4809 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4810 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4811 single basic block in the original CFG and the new basic block is
4812 returned. DEST_CFUN must not have a CFG yet.
4814 Note that the region need not be a pure SESE region. Blocks inside
4815 the region may contain calls to abort/exit. The only restriction
4816 is that ENTRY_BB should be the only entry point and it must
4819 All local variables referenced in the region are assumed to be in
4820 the corresponding BLOCK_VARS and unexpanded variable lists
4821 associated with DEST_CFUN. */
4824 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4825 basic_block exit_bb
)
4827 VEC(basic_block
,heap
) *bbs
;
4828 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4829 struct function
*saved_cfun
;
4830 int *entry_flag
, *exit_flag
, eh_offset
;
4831 unsigned i
, num_entry_edges
, num_exit_edges
;
4834 bitmap vars_to_remove
;
4835 htab_t new_label_map
;
4839 /* Collect all the blocks in the region. Manually add ENTRY_BB
4840 because it won't be added by dfs_enumerate_from. */
4841 calculate_dominance_info (CDI_DOMINATORS
);
4843 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4845 gcc_assert (entry_bb
!= exit_bb
4847 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4850 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4851 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4853 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4854 the predecessor edges to ENTRY_BB and the successor edges to
4855 EXIT_BB so that we can re-attach them to the new basic block that
4856 will replace the region. */
4857 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4858 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4859 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4861 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4863 entry_flag
[i
] = e
->flags
;
4864 entry_pred
[i
++] = e
->src
;
4870 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4871 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4872 sizeof (basic_block
));
4873 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4875 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4877 exit_flag
[i
] = e
->flags
;
4878 exit_succ
[i
++] = e
->dest
;
4889 /* Switch context to the child function to initialize DEST_FN's CFG. */
4890 gcc_assert (dest_cfun
->cfg
== NULL
);
4893 init_empty_tree_cfg ();
4895 /* Initialize EH information for the new function. */
4897 new_label_map
= NULL
;
4902 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4903 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4905 init_eh_for_function ();
4908 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4909 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4910 new_label_map
, region
, 0);
4916 /* Move blocks from BBS into DEST_CFUN. */
4917 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4918 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4919 vars_to_remove
= BITMAP_ALLOC (NULL
);
4920 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4922 /* No need to update edge counts on the last block. It has
4923 already been updated earlier when we detached the region from
4924 the original CFG. */
4925 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4926 new_label_map
, eh_offset
);
4931 htab_delete (new_label_map
);
4933 /* Remove the variables marked in VARS_TO_REMOVE from
4934 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4935 DECL_RTL in the context of CFUN. */
4936 if (!bitmap_empty_p (vars_to_remove
))
4940 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4942 tree var
= TREE_VALUE (*p
);
4943 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4945 *p
= TREE_CHAIN (*p
);
4949 p
= &TREE_CHAIN (*p
);
4953 BITMAP_FREE (vars_to_remove
);
4955 /* Rewire the entry and exit blocks. The successor to the entry
4956 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4957 the child function. Similarly, the predecessor of DEST_FN's
4958 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4959 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4960 various CFG manipulation function get to the right CFG.
4962 FIXME, this is silly. The CFG ought to become a parameter to
4965 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4967 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4970 /* Back in the original function, the SESE region has disappeared,
4971 create a new basic block in its place. */
4972 bb
= create_empty_bb (entry_pred
[0]);
4973 for (i
= 0; i
< num_entry_edges
; i
++)
4974 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4976 for (i
= 0; i
< num_exit_edges
; i
++)
4977 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4986 free_dominance_info (CDI_DOMINATORS
);
4987 free_dominance_info (CDI_POST_DOMINATORS
);
4988 VEC_free (basic_block
, heap
, bbs
);
4994 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4997 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4999 tree arg
, vars
, var
;
5000 bool ignore_topmost_bind
= false, any_var
= false;
5003 struct function
*saved_cfun
;
5005 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5007 arg
= DECL_ARGUMENTS (fn
);
5010 print_generic_expr (file
, arg
, dump_flags
);
5011 if (TREE_CHAIN (arg
))
5012 fprintf (file
, ", ");
5013 arg
= TREE_CHAIN (arg
);
5015 fprintf (file
, ")\n");
5017 if (flags
& TDF_DETAILS
)
5018 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
5019 if (flags
& TDF_RAW
)
5021 dump_node (fn
, TDF_SLIM
| flags
, file
);
5025 /* Switch CFUN to point to FN. */
5027 cfun
= DECL_STRUCT_FUNCTION (fn
);
5029 /* When GIMPLE is lowered, the variables are no longer available in
5030 BIND_EXPRs, so display them separately. */
5031 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5033 ignore_topmost_bind
= true;
5035 fprintf (file
, "{\n");
5036 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5038 var
= TREE_VALUE (vars
);
5040 print_generic_decl (file
, var
, flags
);
5041 fprintf (file
, "\n");
5047 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5049 /* Make a CFG based dump. */
5050 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5051 if (!ignore_topmost_bind
)
5052 fprintf (file
, "{\n");
5054 if (any_var
&& n_basic_blocks
)
5055 fprintf (file
, "\n");
5058 dump_generic_bb (file
, bb
, 2, flags
);
5060 fprintf (file
, "}\n");
5061 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5067 /* Make a tree based dump. */
5068 chain
= DECL_SAVED_TREE (fn
);
5070 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5072 if (ignore_topmost_bind
)
5074 chain
= BIND_EXPR_BODY (chain
);
5082 if (!ignore_topmost_bind
)
5083 fprintf (file
, "{\n");
5088 fprintf (file
, "\n");
5090 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5091 if (ignore_topmost_bind
)
5092 fprintf (file
, "}\n");
5095 fprintf (file
, "\n\n");
5102 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5105 debug_function (tree fn
, int flags
)
5107 dump_function_to_file (fn
, stderr
, flags
);
5111 /* Pretty print of the loops intermediate representation. */
5112 static void print_loop (FILE *, struct loop
*, int);
5113 static void print_pred_bbs (FILE *, basic_block bb
);
5114 static void print_succ_bbs (FILE *, basic_block bb
);
5117 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5120 print_pred_bbs (FILE *file
, basic_block bb
)
5125 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5126 fprintf (file
, "bb_%d ", e
->src
->index
);
5130 /* Print on FILE the indexes for the successors of basic_block BB. */
5133 print_succ_bbs (FILE *file
, basic_block bb
)
5138 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5139 fprintf (file
, "bb_%d ", e
->dest
->index
);
5143 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5146 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5154 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5155 memset ((void *) s_indent
, ' ', (size_t) indent
);
5156 s_indent
[indent
] = '\0';
5158 /* Print the loop's header. */
5159 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5161 /* Print the loop's body. */
5162 fprintf (file
, "%s{\n", s_indent
);
5164 if (bb
->loop_father
== loop
)
5166 /* Print the basic_block's header. */
5167 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5168 print_pred_bbs (file
, bb
);
5169 fprintf (file
, "}, succs = {");
5170 print_succ_bbs (file
, bb
);
5171 fprintf (file
, "})\n");
5173 /* Print the basic_block's body. */
5174 fprintf (file
, "%s {\n", s_indent
);
5175 tree_dump_bb (bb
, file
, indent
+ 4);
5176 fprintf (file
, "%s }\n", s_indent
);
5179 print_loop (file
, loop
->inner
, indent
+ 2);
5180 fprintf (file
, "%s}\n", s_indent
);
5181 print_loop (file
, loop
->next
, indent
);
5185 /* Follow a CFG edge from the entry point of the program, and on entry
5186 of a loop, pretty print the loop structure on FILE. */
5189 print_loop_ir (FILE *file
)
5193 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5194 if (bb
&& bb
->loop_father
)
5195 print_loop (file
, bb
->loop_father
, 0);
5199 /* Debugging loops structure at tree level. */
5202 debug_loop_ir (void)
5204 print_loop_ir (stderr
);
5208 /* Return true if BB ends with a call, possibly followed by some
5209 instructions that must stay with the call. Return false,
5213 tree_block_ends_with_call_p (basic_block bb
)
5215 block_stmt_iterator bsi
= bsi_last (bb
);
5216 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5220 /* Return true if BB ends with a conditional branch. Return false,
5224 tree_block_ends_with_condjump_p (basic_block bb
)
5226 tree stmt
= last_stmt (bb
);
5227 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5231 /* Return true if we need to add fake edge to exit at statement T.
5232 Helper function for tree_flow_call_edges_add. */
5235 need_fake_edge_p (tree t
)
5239 /* NORETURN and LONGJMP calls already have an edge to exit.
5240 CONST and PURE calls do not need one.
5241 We don't currently check for CONST and PURE here, although
5242 it would be a good idea, because those attributes are
5243 figured out from the RTL in mark_constant_function, and
5244 the counter incrementation code from -fprofile-arcs
5245 leads to different results from -fbranch-probabilities. */
5246 call
= get_call_expr_in (t
);
5248 && !(call_expr_flags (call
) & ECF_NORETURN
))
5251 if (TREE_CODE (t
) == ASM_EXPR
5252 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5259 /* Add fake edges to the function exit for any non constant and non
5260 noreturn calls, volatile inline assembly in the bitmap of blocks
5261 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5262 the number of blocks that were split.
5264 The goal is to expose cases in which entering a basic block does
5265 not imply that all subsequent instructions must be executed. */
5268 tree_flow_call_edges_add (sbitmap blocks
)
5271 int blocks_split
= 0;
5272 int last_bb
= last_basic_block
;
5273 bool check_last_block
= false;
5275 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5279 check_last_block
= true;
5281 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5283 /* In the last basic block, before epilogue generation, there will be
5284 a fallthru edge to EXIT. Special care is required if the last insn
5285 of the last basic block is a call because make_edge folds duplicate
5286 edges, which would result in the fallthru edge also being marked
5287 fake, which would result in the fallthru edge being removed by
5288 remove_fake_edges, which would result in an invalid CFG.
5290 Moreover, we can't elide the outgoing fake edge, since the block
5291 profiler needs to take this into account in order to solve the minimal
5292 spanning tree in the case that the call doesn't return.
5294 Handle this by adding a dummy instruction in a new last basic block. */
5295 if (check_last_block
)
5297 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5298 block_stmt_iterator bsi
= bsi_last (bb
);
5300 if (!bsi_end_p (bsi
))
5303 if (t
&& need_fake_edge_p (t
))
5307 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5310 bsi_insert_on_edge (e
, build_empty_stmt ());
5311 bsi_commit_edge_inserts ();
5316 /* Now add fake edges to the function exit for any non constant
5317 calls since there is no way that we can determine if they will
5319 for (i
= 0; i
< last_bb
; i
++)
5321 basic_block bb
= BASIC_BLOCK (i
);
5322 block_stmt_iterator bsi
;
5323 tree stmt
, last_stmt
;
5328 if (blocks
&& !TEST_BIT (blocks
, i
))
5331 bsi
= bsi_last (bb
);
5332 if (!bsi_end_p (bsi
))
5334 last_stmt
= bsi_stmt (bsi
);
5337 stmt
= bsi_stmt (bsi
);
5338 if (need_fake_edge_p (stmt
))
5341 /* The handling above of the final block before the
5342 epilogue should be enough to verify that there is
5343 no edge to the exit block in CFG already.
5344 Calling make_edge in such case would cause us to
5345 mark that edge as fake and remove it later. */
5346 #ifdef ENABLE_CHECKING
5347 if (stmt
== last_stmt
)
5349 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5350 gcc_assert (e
== NULL
);
5354 /* Note that the following may create a new basic block
5355 and renumber the existing basic blocks. */
5356 if (stmt
!= last_stmt
)
5358 e
= split_block (bb
, stmt
);
5362 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5366 while (!bsi_end_p (bsi
));
5371 verify_flow_info ();
5373 return blocks_split
;
5376 /* Purge dead abnormal call edges from basic block BB. */
5379 tree_purge_dead_abnormal_call_edges (basic_block bb
)
5381 bool changed
= tree_purge_dead_eh_edges (bb
);
5383 if (current_function_has_nonlocal_label
)
5385 tree stmt
= last_stmt (bb
);
5389 if (!(stmt
&& tree_can_make_abnormal_goto (stmt
)))
5390 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5392 if (e
->flags
& EDGE_ABNORMAL
)
5401 /* See tree_purge_dead_eh_edges below. */
5403 free_dominance_info (CDI_DOMINATORS
);
5409 /* Purge dead EH edges from basic block BB. */
5412 tree_purge_dead_eh_edges (basic_block bb
)
5414 bool changed
= false;
5417 tree stmt
= last_stmt (bb
);
5419 if (stmt
&& tree_can_throw_internal (stmt
))
5422 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5424 if (e
->flags
& EDGE_EH
)
5433 /* Removal of dead EH edges might change dominators of not
5434 just immediate successors. E.g. when bb1 is changed so that
5435 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5436 eh edges purged by this function in:
5448 idom(bb5) must be recomputed. For now just free the dominance
5451 free_dominance_info (CDI_DOMINATORS
);
5457 tree_purge_all_dead_eh_edges (bitmap blocks
)
5459 bool changed
= false;
5463 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5465 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5471 /* This function is called whenever a new edge is created or
5475 tree_execute_on_growing_pred (edge e
)
5477 basic_block bb
= e
->dest
;
5480 reserve_phi_args_for_new_edge (bb
);
5483 /* This function is called immediately before edge E is removed from
5484 the edge vector E->dest->preds. */
5487 tree_execute_on_shrinking_pred (edge e
)
5489 if (phi_nodes (e
->dest
))
5490 remove_phi_args (e
);
5493 /*---------------------------------------------------------------------------
5494 Helper functions for Loop versioning
5495 ---------------------------------------------------------------------------*/
5497 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5498 of 'first'. Both of them are dominated by 'new_head' basic block. When
5499 'new_head' was created by 'second's incoming edge it received phi arguments
5500 on the edge by split_edge(). Later, additional edge 'e' was created to
5501 connect 'new_head' and 'first'. Now this routine adds phi args on this
5502 additional edge 'e' that new_head to second edge received as part of edge
5507 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5508 basic_block new_head
, edge e
)
5511 edge e2
= find_edge (new_head
, second
);
5513 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5514 edge, we should always have an edge from NEW_HEAD to SECOND. */
5515 gcc_assert (e2
!= NULL
);
5517 /* Browse all 'second' basic block phi nodes and add phi args to
5518 edge 'e' for 'first' head. PHI args are always in correct order. */
5520 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5522 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5524 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5525 add_phi_arg (phi1
, def
, e
);
5529 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5530 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5531 the destination of the ELSE part. */
5533 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5534 basic_block cond_bb
, void *cond_e
)
5536 block_stmt_iterator bsi
;
5537 tree goto1
= NULL_TREE
;
5538 tree goto2
= NULL_TREE
;
5539 tree new_cond_expr
= NULL_TREE
;
5540 tree cond_expr
= (tree
) cond_e
;
5543 /* Build new conditional expr */
5544 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5545 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5546 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5548 /* Add new cond in cond_bb. */
5549 bsi
= bsi_start (cond_bb
);
5550 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5551 /* Adjust edges appropriately to connect new head with first head
5552 as well as second head. */
5553 e0
= single_succ_edge (cond_bb
);
5554 e0
->flags
&= ~EDGE_FALLTHRU
;
5555 e0
->flags
|= EDGE_FALSE_VALUE
;
5558 struct cfg_hooks tree_cfg_hooks
= {
5560 tree_verify_flow_info
,
5561 tree_dump_bb
, /* dump_bb */
5562 create_bb
, /* create_basic_block */
5563 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5564 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5565 remove_bb
, /* delete_basic_block */
5566 tree_split_block
, /* split_block */
5567 tree_move_block_after
, /* move_block_after */
5568 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5569 tree_merge_blocks
, /* merge_blocks */
5570 tree_predict_edge
, /* predict_edge */
5571 tree_predicted_by_p
, /* predicted_by_p */
5572 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5573 tree_duplicate_bb
, /* duplicate_block */
5574 tree_split_edge
, /* split_edge */
5575 tree_make_forwarder_block
, /* make_forward_block */
5576 NULL
, /* tidy_fallthru_edge */
5577 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5578 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5579 tree_flow_call_edges_add
, /* flow_call_edges_add */
5580 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5581 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5582 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5583 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5584 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5585 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5586 flush_pending_stmts
/* flush_pending_stmts */
5590 /* Split all critical edges. */
5593 split_critical_edges (void)
5599 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5600 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5601 mappings around the calls to split_edge. */
5602 start_recording_case_labels ();
5605 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5606 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5611 end_recording_case_labels ();
5615 struct tree_opt_pass pass_split_crit_edges
=
5617 "crited", /* name */
5619 split_critical_edges
, /* execute */
5622 0, /* static_pass_number */
5623 TV_TREE_SPLIT_EDGES
, /* tv_id */
5624 PROP_cfg
, /* properties required */
5625 PROP_no_crit_edges
, /* properties_provided */
5626 0, /* properties_destroyed */
5627 0, /* todo_flags_start */
5628 TODO_dump_func
, /* todo_flags_finish */
5633 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5634 a temporary, make sure and register it to be renamed if necessary,
5635 and finally return the temporary. Put the statements to compute
5636 EXP before the current statement in BSI. */
5639 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5641 tree t
, new_stmt
, orig_stmt
;
5643 if (is_gimple_val (exp
))
5646 t
= make_rename_temp (type
, NULL
);
5647 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5649 orig_stmt
= bsi_stmt (*bsi
);
5650 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5651 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5653 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5655 mark_new_vars_to_rename (new_stmt
);
5660 /* Build a ternary operation and gimplify it. Emit code before BSI.
5661 Return the gimple_val holding the result. */
5664 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5665 tree type
, tree a
, tree b
, tree c
)
5669 ret
= fold_build3 (code
, type
, a
, b
, c
);
5672 return gimplify_val (bsi
, type
, ret
);
5675 /* Build a binary operation and gimplify it. Emit code before BSI.
5676 Return the gimple_val holding the result. */
5679 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5680 tree type
, tree a
, tree b
)
5684 ret
= fold_build2 (code
, type
, a
, b
);
5687 return gimplify_val (bsi
, type
, ret
);
5690 /* Build a unary operation and gimplify it. Emit code before BSI.
5691 Return the gimple_val holding the result. */
5694 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5699 ret
= fold_build1 (code
, type
, a
);
5702 return gimplify_val (bsi
, type
, ret
);
5707 /* Emit return warnings. */
5710 execute_warn_function_return (void)
5712 #ifdef USE_MAPPED_LOCATION
5713 source_location location
;
5721 /* If we have a path to EXIT, then we do return. */
5722 if (TREE_THIS_VOLATILE (cfun
->decl
)
5723 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5725 #ifdef USE_MAPPED_LOCATION
5726 location
= UNKNOWN_LOCATION
;
5730 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5732 last
= last_stmt (e
->src
);
5733 if (TREE_CODE (last
) == RETURN_EXPR
5734 #ifdef USE_MAPPED_LOCATION
5735 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5737 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5741 #ifdef USE_MAPPED_LOCATION
5742 if (location
== UNKNOWN_LOCATION
)
5743 location
= cfun
->function_end_locus
;
5744 warning (0, "%H%<noreturn%> function does return", &location
);
5747 locus
= &cfun
->function_end_locus
;
5748 warning (0, "%H%<noreturn%> function does return", locus
);
5752 /* If we see "return;" in some basic block, then we do reach the end
5753 without returning a value. */
5754 else if (warn_return_type
5755 && !TREE_NO_WARNING (cfun
->decl
)
5756 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5757 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5759 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5761 tree last
= last_stmt (e
->src
);
5762 if (TREE_CODE (last
) == RETURN_EXPR
5763 && TREE_OPERAND (last
, 0) == NULL
5764 && !TREE_NO_WARNING (last
))
5766 #ifdef USE_MAPPED_LOCATION
5767 location
= EXPR_LOCATION (last
);
5768 if (location
== UNKNOWN_LOCATION
)
5769 location
= cfun
->function_end_locus
;
5770 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5772 locus
= EXPR_LOCUS (last
);
5774 locus
= &cfun
->function_end_locus
;
5775 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5777 TREE_NO_WARNING (cfun
->decl
) = 1;
5786 /* Given a basic block B which ends with a conditional and has
5787 precisely two successors, determine which of the edges is taken if
5788 the conditional is true and which is taken if the conditional is
5789 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5792 extract_true_false_edges_from_block (basic_block b
,
5796 edge e
= EDGE_SUCC (b
, 0);
5798 if (e
->flags
& EDGE_TRUE_VALUE
)
5801 *false_edge
= EDGE_SUCC (b
, 1);
5806 *true_edge
= EDGE_SUCC (b
, 1);
5810 struct tree_opt_pass pass_warn_function_return
=
5814 execute_warn_function_return
, /* execute */
5817 0, /* static_pass_number */
5819 PROP_cfg
, /* properties_required */
5820 0, /* properties_provided */
5821 0, /* properties_destroyed */
5822 0, /* todo_flags_start */
5823 0, /* todo_flags_finish */
5827 /* Emit noreturn warnings. */
5830 execute_warn_function_noreturn (void)
5832 if (warn_missing_noreturn
5833 && !TREE_THIS_VOLATILE (cfun
->decl
)
5834 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5835 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5836 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5837 "for attribute %<noreturn%>",
5842 struct tree_opt_pass pass_warn_function_noreturn
=
5846 execute_warn_function_noreturn
, /* execute */
5849 0, /* static_pass_number */
5851 PROP_cfg
, /* properties_required */
5852 0, /* properties_provided */
5853 0, /* properties_destroyed */
5854 0, /* todo_flags_start */
5855 0, /* todo_flags_finish */