1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
36 #include "langhooks.h"
37 #include "diagnostic.h"
38 #include "tree-flow.h"
40 #include "tree-dump.h"
41 #include "tree-pass.h"
45 #include "cfglayout.h"
47 #include "tree-ssa-propagate.h"
49 /* This file contains functions for building the Control Flow Graph (CFG)
50 for a function tree. */
52 /* Local declarations. */
54 /* Initial capacity for the basic block array. */
55 static const int initial_cfg_capacity
= 20;
57 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
58 which use a particular edge. The CASE_LABEL_EXPRs are chained together
59 via their TREE_CHAIN field, which we clear after we're done with the
60 hash table to prevent problems with duplication of SWITCH_EXPRs.
62 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
63 update the case vector in response to edge redirections.
65 Right now this table is set up and torn down at key points in the
66 compilation process. It would be nice if we could make the table
67 more persistent. The key is getting notification of changes to
68 the CFG (particularly edge removal, creation and redirection). */
70 struct edge_to_cases_elt
72 /* The edge itself. Necessary for hashing and equality tests. */
75 /* The case labels associated with this edge. We link these up via
76 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
77 when we destroy the hash table. This prevents problems when copying
82 static htab_t edge_to_cases
;
87 long num_merged_labels
;
90 static struct cfg_stats_d cfg_stats
;
92 /* Nonzero if we found a computed goto while building basic blocks. */
93 static bool found_computed_goto
;
95 /* Basic blocks and flowgraphs. */
96 static basic_block
create_bb (void *, void *, basic_block
);
97 static void make_blocks (tree
);
98 static void factor_computed_gotos (void);
101 static void make_edges (void);
102 static void make_ctrl_stmt_edges (basic_block
);
103 static void make_exit_edges (basic_block
);
104 static void make_cond_expr_edges (basic_block
);
105 static void make_switch_expr_edges (basic_block
);
106 static void make_goto_expr_edges (basic_block
);
107 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
108 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
109 static void split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree
, tree
);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge
);
115 static void tree_cfg2vcg (FILE *);
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
;
133 last_basic_block
= 0;
134 VARRAY_BB_INIT (basic_block_info
, initial_cfg_capacity
, "basic_block_info");
136 /* Build a mapping of labels to their associated blocks. */
137 VARRAY_BB_INIT (label_to_block_map
, initial_cfg_capacity
,
138 "label to block map");
140 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
141 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
144 /*---------------------------------------------------------------------------
146 ---------------------------------------------------------------------------*/
148 /* Entry point to the CFG builder for trees. TP points to the list of
149 statements to be added to the flowgraph. */
152 build_tree_cfg (tree
*tp
)
154 /* Register specific tree functions. */
155 tree_register_cfg_hooks ();
157 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
159 init_empty_tree_cfg ();
161 found_computed_goto
= 0;
164 /* Computed gotos are hell to deal with, especially if there are
165 lots of them with a large number of destinations. So we factor
166 them to a common computed goto location before we build the
167 edge list. After we convert back to normal form, we will un-factor
168 the computed gotos since factoring introduces an unwanted jump. */
169 if (found_computed_goto
)
170 factor_computed_gotos ();
172 /* Make sure there is always at least one block, even if it's empty. */
173 if (n_basic_blocks
== 0)
174 create_empty_bb (ENTRY_BLOCK_PTR
);
176 /* Adjust the size of the array. */
177 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
179 /* To speed up statement iterator walks, we first purge dead labels. */
180 cleanup_dead_labels ();
182 /* Group case nodes to reduce the number of edges.
183 We do this after cleaning up dead labels because otherwise we miss
184 a lot of obvious case merging opportunities. */
185 group_case_labels ();
187 /* Create the edges of the flowgraph. */
190 /* Debugging dumps. */
192 /* Write the flowgraph to a VCG file. */
194 int local_dump_flags
;
195 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
198 tree_cfg2vcg (dump_file
);
199 dump_end (TDI_vcg
, dump_file
);
203 #ifdef ENABLE_CHECKING
207 /* Dump a textual representation of the flowgraph. */
209 dump_tree_cfg (dump_file
, dump_flags
);
213 execute_build_cfg (void)
215 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
218 struct tree_opt_pass pass_build_cfg
=
222 execute_build_cfg
, /* execute */
225 0, /* static_pass_number */
226 TV_TREE_CFG
, /* tv_id */
227 PROP_gimple_leh
, /* properties_required */
228 PROP_cfg
, /* properties_provided */
229 0, /* properties_destroyed */
230 0, /* todo_flags_start */
231 TODO_verify_stmts
, /* todo_flags_finish */
235 /* Search the CFG for any computed gotos. If found, factor them to a
236 common computed goto site. Also record the location of that site so
237 that we can un-factor the gotos after we have converted back to
241 factor_computed_gotos (void)
244 tree factored_label_decl
= NULL
;
246 tree factored_computed_goto_label
= NULL
;
247 tree factored_computed_goto
= NULL
;
249 /* We know there are one or more computed gotos in this function.
250 Examine the last statement in each basic block to see if the block
251 ends with a computed goto. */
255 block_stmt_iterator bsi
= bsi_last (bb
);
260 last
= bsi_stmt (bsi
);
262 /* Ignore the computed goto we create when we factor the original
264 if (last
== factored_computed_goto
)
267 /* If the last statement is a computed goto, factor it. */
268 if (computed_goto_p (last
))
272 /* The first time we find a computed goto we need to create
273 the factored goto block and the variable each original
274 computed goto will use for their goto destination. */
275 if (! factored_computed_goto
)
277 basic_block new_bb
= create_empty_bb (bb
);
278 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
280 /* Create the destination of the factored goto. Each original
281 computed goto will put its desired destination into this
282 variable and jump to the label we create immediately
284 var
= create_tmp_var (ptr_type_node
, "gotovar");
286 /* Build a label for the new block which will contain the
287 factored computed goto. */
288 factored_label_decl
= create_artificial_label ();
289 factored_computed_goto_label
290 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
291 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
294 /* Build our new computed goto. */
295 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
296 bsi_insert_after (&new_bsi
, factored_computed_goto
,
300 /* Copy the original computed goto's destination into VAR. */
301 assignment
= build (MODIFY_EXPR
, ptr_type_node
,
302 var
, GOTO_DESTINATION (last
));
303 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
305 /* And re-vector the computed goto to the new destination. */
306 GOTO_DESTINATION (last
) = factored_label_decl
;
312 /* Build a flowgraph for the statement_list STMT_LIST. */
315 make_blocks (tree stmt_list
)
317 tree_stmt_iterator i
= tsi_start (stmt_list
);
319 bool start_new_block
= true;
320 bool first_stmt_of_list
= true;
321 basic_block bb
= ENTRY_BLOCK_PTR
;
323 while (!tsi_end_p (i
))
330 /* If the statement starts a new basic block or if we have determined
331 in a previous pass that we need to create a new block for STMT, do
333 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
335 if (!first_stmt_of_list
)
336 stmt_list
= tsi_split_statement_list_before (&i
);
337 bb
= create_basic_block (stmt_list
, NULL
, bb
);
338 start_new_block
= false;
341 /* Now add STMT to BB and create the subgraphs for special statement
343 set_bb_for_stmt (stmt
, bb
);
345 if (computed_goto_p (stmt
))
346 found_computed_goto
= true;
348 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
350 if (stmt_ends_bb_p (stmt
))
351 start_new_block
= true;
354 first_stmt_of_list
= false;
359 /* Create and return a new empty basic block after bb AFTER. */
362 create_bb (void *h
, void *e
, basic_block after
)
368 /* Create and initialize a new basic block. Since alloc_block uses
369 ggc_alloc_cleared to allocate a basic block, we do not have to
370 clear the newly allocated basic block here. */
373 bb
->index
= last_basic_block
;
375 bb
->stmt_list
= h
? h
: alloc_stmt_list ();
377 /* Add the new block to the linked list of blocks. */
378 link_block (bb
, after
);
380 /* Grow the basic block array if needed. */
381 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
383 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
384 VARRAY_GROW (basic_block_info
, new_size
);
387 /* Add the newly created block to the array. */
388 BASIC_BLOCK (last_basic_block
) = bb
;
397 /*---------------------------------------------------------------------------
399 ---------------------------------------------------------------------------*/
401 /* Fold COND_EXPR_COND of each COND_EXPR. */
404 fold_cond_expr_cond (void)
410 tree stmt
= last_stmt (bb
);
413 && TREE_CODE (stmt
) == COND_EXPR
)
415 tree cond
= fold (COND_EXPR_COND (stmt
));
416 if (integer_zerop (cond
))
417 COND_EXPR_COND (stmt
) = boolean_false_node
;
418 else if (integer_onep (cond
))
419 COND_EXPR_COND (stmt
) = boolean_true_node
;
424 /* Mark the array of any remaining ARRAY_REFs as addressable. */
427 mark_array_ref_addressable_1 (tree
*tp
, int *walk_subtrees
,
428 void *data ATTRIBUTE_UNUSED
)
432 if (DECL_P (t
) || TYPE_P (t
))
434 else if (TREE_CODE (t
) == ARRAY_REF
)
436 tree base
= get_base_address (TREE_OPERAND (t
, 0));
437 if (base
&& DECL_P (base
))
438 TREE_ADDRESSABLE (base
) = 1;
445 mark_array_ref_addressable (void)
448 block_stmt_iterator i
;
452 for (i
= bsi_start (bb
); !bsi_end_p(i
); bsi_next(&i
))
453 walk_tree (bsi_stmt_ptr (i
), mark_array_ref_addressable_1
, NULL
, NULL
);
457 /* Join all the blocks in the flowgraph. */
464 /* Create an edge from entry to the first block with executable
466 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (0), EDGE_FALLTHRU
);
468 /* Traverse the basic block array placing edges. */
471 tree first
= first_stmt (bb
);
472 tree last
= last_stmt (bb
);
476 /* Edges for statements that always alter flow control. */
477 if (is_ctrl_stmt (last
))
478 make_ctrl_stmt_edges (bb
);
480 /* Edges for statements that sometimes alter flow control. */
481 if (is_ctrl_altering_stmt (last
))
482 make_exit_edges (bb
);
485 /* Finally, if no edges were created above, this is a regular
486 basic block that only needs a fallthru edge. */
487 if (EDGE_COUNT (bb
->succs
) == 0)
488 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
491 /* We do not care about fake edges, so remove any that the CFG
492 builder inserted for completeness. */
493 remove_fake_exit_edges ();
495 /* Fold COND_EXPR_COND of each COND_EXPR. */
496 fold_cond_expr_cond ();
498 /* Clean up the graph and warn for unreachable code. */
503 /* Create edges for control statement at basic block BB. */
506 make_ctrl_stmt_edges (basic_block bb
)
508 tree last
= last_stmt (bb
);
511 switch (TREE_CODE (last
))
514 make_goto_expr_edges (bb
);
518 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
522 make_cond_expr_edges (bb
);
526 make_switch_expr_edges (bb
);
530 make_eh_edges (last
);
531 /* Yet another NORETURN hack. */
532 if (EDGE_COUNT (bb
->succs
) == 0)
533 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
542 /* Create exit edges for statements in block BB that alter the flow of
543 control. Statements that alter the control flow are 'goto', 'return'
544 and calls to non-returning functions. */
547 make_exit_edges (basic_block bb
)
549 tree last
= last_stmt (bb
), op
;
552 switch (TREE_CODE (last
))
557 /* If this function receives a nonlocal goto, then we need to
558 make edges from this call site to all the nonlocal goto
560 if (TREE_SIDE_EFFECTS (last
)
561 && current_function_has_nonlocal_label
)
562 make_goto_expr_edges (bb
);
564 /* If this statement has reachable exception handlers, then
565 create abnormal edges to them. */
566 make_eh_edges (last
);
568 /* Some calls are known not to return. For such calls we create
571 We really need to revamp how we build edges so that it's not
572 such a bloody pain to avoid creating edges for this case since
573 all we do is remove these edges when we're done building the
575 if (call_expr_flags (last
) & ECF_NORETURN
)
577 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
581 /* Don't forget the fall-thru edge. */
582 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
586 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
587 may have an abnormal edge. Search the RHS for this case and
588 create any required edges. */
589 op
= get_call_expr_in (last
);
590 if (op
&& TREE_SIDE_EFFECTS (op
)
591 && current_function_has_nonlocal_label
)
592 make_goto_expr_edges (bb
);
594 make_eh_edges (last
);
595 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
604 /* Create the edges for a COND_EXPR starting at block BB.
605 At this point, both clauses must contain only simple gotos. */
608 make_cond_expr_edges (basic_block bb
)
610 tree entry
= last_stmt (bb
);
611 basic_block then_bb
, else_bb
;
612 tree then_label
, else_label
;
616 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
618 /* Entry basic blocks for each component. */
619 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
620 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
621 then_bb
= label_to_block (then_label
);
622 else_bb
= label_to_block (else_label
);
624 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
625 #ifdef USE_MAPPED_LOCATION
626 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
628 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
630 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
633 #ifdef USE_MAPPED_LOCATION
634 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
636 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
641 /* Hashing routine for EDGE_TO_CASES. */
644 edge_to_cases_hash (const void *p
)
646 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
648 /* Hash on the edge itself (which is a pointer). */
649 return htab_hash_pointer (e
);
652 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
653 for equality is just a pointer comparison. */
656 edge_to_cases_eq (const void *p1
, const void *p2
)
658 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
659 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
664 /* Called for each element in the hash table (P) as we delete the
665 edge to cases hash table.
667 Clear all the TREE_CHAINs to prevent problems with copying of
668 SWITCH_EXPRs and structure sharing rules, then free the hash table
672 edge_to_cases_cleanup (void *p
)
674 struct edge_to_cases_elt
*elt
= p
;
677 for (t
= elt
->case_labels
; t
; t
= next
)
679 next
= TREE_CHAIN (t
);
680 TREE_CHAIN (t
) = NULL
;
685 /* Start recording information mapping edges to case labels. */
688 start_recording_case_labels (void)
690 gcc_assert (edge_to_cases
== NULL
);
692 edge_to_cases
= htab_create (37,
695 edge_to_cases_cleanup
);
698 /* Return nonzero if we are recording information for case labels. */
701 recording_case_labels_p (void)
703 return (edge_to_cases
!= NULL
);
706 /* Stop recording information mapping edges to case labels and
707 remove any information we have recorded. */
709 end_recording_case_labels (void)
711 htab_delete (edge_to_cases
);
712 edge_to_cases
= NULL
;
715 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
718 record_switch_edge (edge e
, tree case_label
)
720 struct edge_to_cases_elt
*elt
;
723 /* Build a hash table element so we can see if E is already
725 elt
= xmalloc (sizeof (struct edge_to_cases_elt
));
727 elt
->case_labels
= case_label
;
729 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
733 /* E was not in the hash table. Install E into the hash table. */
738 /* E was already in the hash table. Free ELT as we do not need it
742 /* Get the entry stored in the hash table. */
743 elt
= (struct edge_to_cases_elt
*) *slot
;
745 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
746 TREE_CHAIN (case_label
) = elt
->case_labels
;
747 elt
->case_labels
= case_label
;
751 /* If we are inside a {start,end}_recording_cases block, then return
752 a chain of CASE_LABEL_EXPRs from T which reference E.
754 Otherwise return NULL. */
757 get_cases_for_edge (edge e
, tree t
)
759 struct edge_to_cases_elt elt
, *elt_p
;
764 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
765 chains available. Return NULL so the caller can detect this case. */
766 if (!recording_case_labels_p ())
771 elt
.case_labels
= NULL
;
772 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
776 elt_p
= (struct edge_to_cases_elt
*)*slot
;
777 return elt_p
->case_labels
;
780 /* If we did not find E in the hash table, then this must be the first
781 time we have been queried for information about E & T. Add all the
782 elements from T to the hash table then perform the query again. */
784 vec
= SWITCH_LABELS (t
);
785 n
= TREE_VEC_LENGTH (vec
);
786 for (i
= 0; i
< n
; i
++)
788 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
789 basic_block label_bb
= label_to_block (lab
);
790 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
795 /* Create the edges for a SWITCH_EXPR starting at block BB.
796 At this point, the switch body has been lowered and the
797 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
800 make_switch_expr_edges (basic_block bb
)
802 tree entry
= last_stmt (bb
);
806 vec
= SWITCH_LABELS (entry
);
807 n
= TREE_VEC_LENGTH (vec
);
809 for (i
= 0; i
< n
; ++i
)
811 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
812 basic_block label_bb
= label_to_block (lab
);
813 make_edge (bb
, label_bb
, 0);
818 /* Return the basic block holding label DEST. */
821 label_to_block_fn (struct function
*ifun
, tree dest
)
823 int uid
= LABEL_DECL_UID (dest
);
825 /* We would die hard when faced by an undefined label. Emit a label to
826 the very first basic block. This will hopefully make even the dataflow
827 and undefined variable warnings quite right. */
828 if ((errorcount
|| sorrycount
) && uid
< 0)
830 block_stmt_iterator bsi
= bsi_start (BASIC_BLOCK (0));
833 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
834 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
835 uid
= LABEL_DECL_UID (dest
);
837 if (VARRAY_SIZE (ifun
->cfg
->x_label_to_block_map
) <= (unsigned int)uid
)
839 return VARRAY_BB (ifun
->cfg
->x_label_to_block_map
, uid
);
842 /* Create edges for a goto statement at block BB. */
845 make_goto_expr_edges (basic_block bb
)
848 basic_block target_bb
;
850 block_stmt_iterator last
= bsi_last (bb
);
852 goto_t
= bsi_stmt (last
);
854 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
855 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
856 from a nonlocal goto. */
857 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
861 tree dest
= GOTO_DESTINATION (goto_t
);
864 /* A GOTO to a local label creates normal edges. */
865 if (simple_goto_p (goto_t
))
867 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
868 #ifdef USE_MAPPED_LOCATION
869 e
->goto_locus
= EXPR_LOCATION (goto_t
);
871 e
->goto_locus
= EXPR_LOCUS (goto_t
);
877 /* Nothing more to do for nonlocal gotos. */
878 if (TREE_CODE (dest
) == LABEL_DECL
)
881 /* Computed gotos remain. */
884 /* Look for the block starting with the destination label. In the
885 case of a computed goto, make an edge to any label block we find
887 FOR_EACH_BB (target_bb
)
889 block_stmt_iterator bsi
;
891 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
893 tree target
= bsi_stmt (bsi
);
895 if (TREE_CODE (target
) != LABEL_EXPR
)
899 /* Computed GOTOs. Make an edge to every label block that has
900 been marked as a potential target for a computed goto. */
901 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
902 /* Nonlocal GOTO target. Make an edge to every label block
903 that has been marked as a potential target for a nonlocal
905 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
907 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
913 /* Degenerate case of computed goto with no labels. */
914 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
915 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
919 /*---------------------------------------------------------------------------
921 ---------------------------------------------------------------------------*/
923 /* Cleanup useless labels in basic blocks. This is something we wish
924 to do early because it allows us to group case labels before creating
925 the edges for the CFG, and it speeds up block statement iterators in
927 We only run this pass once, running it more than once is probably not
930 /* A map from basic block index to the leading label of that block. */
931 static tree
*label_for_bb
;
933 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
935 update_eh_label (struct eh_region
*region
)
937 tree old_label
= get_eh_region_tree_label (region
);
941 basic_block bb
= label_to_block (old_label
);
943 /* ??? After optimizing, there may be EH regions with labels
944 that have already been removed from the function body, so
945 there is no basic block for them. */
949 new_label
= label_for_bb
[bb
->index
];
950 set_eh_region_tree_label (region
, new_label
);
954 /* Given LABEL return the first label in the same basic block. */
956 main_block_label (tree label
)
958 basic_block bb
= label_to_block (label
);
960 /* label_to_block possibly inserted undefined label into the chain. */
961 if (!label_for_bb
[bb
->index
])
962 label_for_bb
[bb
->index
] = label
;
963 return label_for_bb
[bb
->index
];
966 /* Cleanup redundant labels. This is a three-step process:
967 1) Find the leading label for each block.
968 2) Redirect all references to labels to the leading labels.
969 3) Cleanup all useless labels. */
972 cleanup_dead_labels (void)
975 label_for_bb
= xcalloc (last_basic_block
, sizeof (tree
));
977 /* Find a suitable label for each block. We use the first user-defined
978 label if there is one, or otherwise just the first label we see. */
981 block_stmt_iterator i
;
983 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
985 tree label
, stmt
= bsi_stmt (i
);
987 if (TREE_CODE (stmt
) != LABEL_EXPR
)
990 label
= LABEL_EXPR_LABEL (stmt
);
992 /* If we have not yet seen a label for the current block,
993 remember this one and see if there are more labels. */
994 if (! label_for_bb
[bb
->index
])
996 label_for_bb
[bb
->index
] = label
;
1000 /* If we did see a label for the current block already, but it
1001 is an artificially created label, replace it if the current
1002 label is a user defined label. */
1003 if (! DECL_ARTIFICIAL (label
)
1004 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
1006 label_for_bb
[bb
->index
] = label
;
1012 /* Now redirect all jumps/branches to the selected label.
1013 First do so for each block ending in a control statement. */
1016 tree stmt
= last_stmt (bb
);
1020 switch (TREE_CODE (stmt
))
1024 tree true_branch
, false_branch
;
1026 true_branch
= COND_EXPR_THEN (stmt
);
1027 false_branch
= COND_EXPR_ELSE (stmt
);
1029 GOTO_DESTINATION (true_branch
)
1030 = main_block_label (GOTO_DESTINATION (true_branch
));
1031 GOTO_DESTINATION (false_branch
)
1032 = main_block_label (GOTO_DESTINATION (false_branch
));
1040 tree vec
= SWITCH_LABELS (stmt
);
1041 size_t n
= TREE_VEC_LENGTH (vec
);
1043 /* Replace all destination labels. */
1044 for (i
= 0; i
< n
; ++i
)
1046 tree elt
= TREE_VEC_ELT (vec
, i
);
1047 tree label
= main_block_label (CASE_LABEL (elt
));
1048 CASE_LABEL (elt
) = label
;
1053 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1054 remove them until after we've created the CFG edges. */
1056 if (! computed_goto_p (stmt
))
1058 GOTO_DESTINATION (stmt
)
1059 = main_block_label (GOTO_DESTINATION (stmt
));
1068 for_each_eh_region (update_eh_label
);
1070 /* Finally, purge dead labels. All user-defined labels and labels that
1071 can be the target of non-local gotos are preserved. */
1074 block_stmt_iterator i
;
1075 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1077 if (! label_for_this_bb
)
1080 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1082 tree label
, stmt
= bsi_stmt (i
);
1084 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1087 label
= LABEL_EXPR_LABEL (stmt
);
1089 if (label
== label_for_this_bb
1090 || ! DECL_ARTIFICIAL (label
)
1091 || DECL_NONLOCAL (label
))
1098 free (label_for_bb
);
1101 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1102 and scan the sorted vector of cases. Combine the ones jumping to the
1104 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1107 group_case_labels (void)
1113 tree stmt
= last_stmt (bb
);
1114 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1116 tree labels
= SWITCH_LABELS (stmt
);
1117 int old_size
= TREE_VEC_LENGTH (labels
);
1118 int i
, j
, new_size
= old_size
;
1119 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1122 /* The default label is always the last case in a switch
1123 statement after gimplification. */
1124 default_label
= CASE_LABEL (default_case
);
1126 /* Look for possible opportunities to merge cases.
1127 Ignore the last element of the label vector because it
1128 must be the default case. */
1130 while (i
< old_size
- 1)
1132 tree base_case
, base_label
, base_high
;
1133 base_case
= TREE_VEC_ELT (labels
, i
);
1135 gcc_assert (base_case
);
1136 base_label
= CASE_LABEL (base_case
);
1138 /* Discard cases that have the same destination as the
1140 if (base_label
== default_label
)
1142 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1148 base_high
= CASE_HIGH (base_case
) ?
1149 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1151 /* Try to merge case labels. Break out when we reach the end
1152 of the label vector or when we cannot merge the next case
1153 label with the current one. */
1154 while (i
< old_size
- 1)
1156 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1157 tree merge_label
= CASE_LABEL (merge_case
);
1158 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1159 integer_one_node
, 1);
1161 /* Merge the cases if they jump to the same place,
1162 and their ranges are consecutive. */
1163 if (merge_label
== base_label
1164 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1166 base_high
= CASE_HIGH (merge_case
) ?
1167 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1168 CASE_HIGH (base_case
) = base_high
;
1169 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1178 /* Compress the case labels in the label vector, and adjust the
1179 length of the vector. */
1180 for (i
= 0, j
= 0; i
< new_size
; i
++)
1182 while (! TREE_VEC_ELT (labels
, j
))
1184 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1186 TREE_VEC_LENGTH (labels
) = new_size
;
1191 /* Checks whether we can merge block B into block A. */
1194 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1197 block_stmt_iterator bsi
;
1200 if (!single_succ_p (a
))
1203 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1206 if (single_succ (a
) != b
)
1209 if (!single_pred_p (b
))
1212 if (b
== EXIT_BLOCK_PTR
)
1215 /* If A ends by a statement causing exceptions or something similar, we
1216 cannot merge the blocks. */
1217 stmt
= last_stmt (a
);
1218 if (stmt
&& stmt_ends_bb_p (stmt
))
1221 /* Do not allow a block with only a non-local label to be merged. */
1222 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1223 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1226 /* It must be possible to eliminate all phi nodes in B. If ssa form
1227 is not up-to-date, we cannot eliminate any phis. */
1228 phi
= phi_nodes (b
);
1231 if (need_ssa_update_p ())
1234 for (; phi
; phi
= PHI_CHAIN (phi
))
1235 if (!is_gimple_reg (PHI_RESULT (phi
))
1236 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1240 /* Do not remove user labels. */
1241 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1243 stmt
= bsi_stmt (bsi
);
1244 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1246 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1250 /* Protect the loop latches. */
1252 && b
->loop_father
->latch
== b
)
1258 /* Replaces all uses of NAME by VAL. */
1261 replace_uses_by (tree name
, tree val
)
1263 imm_use_iterator imm_iter
;
1268 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1270 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1272 stmt
= USE_STMT (use
);
1273 replace_exp (use
, val
);
1275 if (TREE_CODE (stmt
) == PHI_NODE
)
1277 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1278 if (e
->flags
& EDGE_ABNORMAL
)
1280 /* This can only occur for virtual operands, since
1281 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1282 would prevent replacement. */
1283 gcc_assert (!is_gimple_reg (name
));
1284 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1288 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1291 /* We do not update the statements in the loop above. Consider
1294 If we performed the update in the first loop, the statement
1295 would be rescanned after first occurrence of w is replaced,
1296 the new uses would be placed to the beginning of the list,
1297 and we would never process them. */
1298 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1302 fold_stmt_inplace (stmt
);
1304 rhs
= get_rhs (stmt
);
1305 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1306 recompute_tree_invarant_for_addr_expr (rhs
);
1308 /* If the statement could throw and now cannot, we need to prune cfg. */
1309 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
1310 tree_purge_dead_eh_edges (bb_for_stmt (stmt
));
1312 mark_new_vars_to_rename (stmt
);
1315 VEC_free (tree
, heap
, stmts
);
1317 /* Also update the trees stored in loop structures. */
1322 for (i
= 0; i
< current_loops
->num
; i
++)
1324 loop
= current_loops
->parray
[i
];
1326 substitute_in_loop_info (loop
, name
, val
);
1331 /* Merge block B into block A. */
1334 tree_merge_blocks (basic_block a
, basic_block b
)
1336 block_stmt_iterator bsi
;
1337 tree_stmt_iterator last
;
1341 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1343 /* Remove all single-valued PHI nodes from block B of the form
1344 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1346 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1348 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1350 bool may_replace_uses
= may_propagate_copy (def
, use
);
1352 /* In case we have loops to care about, do not propagate arguments of
1353 loop closed ssa phi nodes. */
1355 && is_gimple_reg (def
)
1356 && TREE_CODE (use
) == SSA_NAME
1357 && a
->loop_father
!= b
->loop_father
)
1358 may_replace_uses
= false;
1360 if (!may_replace_uses
)
1362 gcc_assert (is_gimple_reg (def
));
1364 /* Note that just emitting the copies is fine -- there is no problem
1365 with ordering of phi nodes. This is because A is the single
1366 predecessor of B, therefore results of the phi nodes cannot
1367 appear as arguments of the phi nodes. */
1368 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1369 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1370 SET_PHI_RESULT (phi
, NULL_TREE
);
1371 SSA_NAME_DEF_STMT (def
) = copy
;
1374 replace_uses_by (def
, use
);
1376 remove_phi_node (phi
, NULL
);
1379 /* Ensure that B follows A. */
1380 move_block_after (b
, a
);
1382 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1383 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1385 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1386 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1388 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1390 tree label
= bsi_stmt (bsi
);
1393 /* Now that we can thread computed gotos, we might have
1394 a situation where we have a forced label in block B
1395 However, the label at the start of block B might still be
1396 used in other ways (think about the runtime checking for
1397 Fortran assigned gotos). So we can not just delete the
1398 label. Instead we move the label to the start of block A. */
1399 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1401 block_stmt_iterator dest_bsi
= bsi_start (a
);
1402 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1407 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1412 /* Merge the chains. */
1413 last
= tsi_last (a
->stmt_list
);
1414 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1415 b
->stmt_list
= NULL
;
1419 /* Walk the function tree removing unnecessary statements.
1421 * Empty statement nodes are removed
1423 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1425 * Unnecessary COND_EXPRs are removed
1427 * Some unnecessary BIND_EXPRs are removed
1429 Clearly more work could be done. The trick is doing the analysis
1430 and removal fast enough to be a net improvement in compile times.
1432 Note that when we remove a control structure such as a COND_EXPR
1433 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1434 to ensure we eliminate all the useless code. */
1445 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1448 remove_useless_stmts_warn_notreached (tree stmt
)
1450 if (EXPR_HAS_LOCATION (stmt
))
1452 location_t loc
= EXPR_LOCATION (stmt
);
1453 if (LOCATION_LINE (loc
) > 0)
1455 warning (0, "%Hwill never be executed", &loc
);
1460 switch (TREE_CODE (stmt
))
1462 case STATEMENT_LIST
:
1464 tree_stmt_iterator i
;
1465 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1466 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1472 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1474 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1476 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1480 case TRY_FINALLY_EXPR
:
1481 case TRY_CATCH_EXPR
:
1482 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1484 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1489 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1490 case EH_FILTER_EXPR
:
1491 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1493 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1496 /* Not a live container. */
1504 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1506 tree then_clause
, else_clause
, cond
;
1507 bool save_has_label
, then_has_label
, else_has_label
;
1509 save_has_label
= data
->has_label
;
1510 data
->has_label
= false;
1511 data
->last_goto
= NULL
;
1513 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1515 then_has_label
= data
->has_label
;
1516 data
->has_label
= false;
1517 data
->last_goto
= NULL
;
1519 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1521 else_has_label
= data
->has_label
;
1522 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1524 then_clause
= COND_EXPR_THEN (*stmt_p
);
1525 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1526 cond
= fold (COND_EXPR_COND (*stmt_p
));
1528 /* If neither arm does anything at all, we can remove the whole IF. */
1529 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1531 *stmt_p
= build_empty_stmt ();
1532 data
->repeat
= true;
1535 /* If there are no reachable statements in an arm, then we can
1536 zap the entire conditional. */
1537 else if (integer_nonzerop (cond
) && !else_has_label
)
1539 if (warn_notreached
)
1540 remove_useless_stmts_warn_notreached (else_clause
);
1541 *stmt_p
= then_clause
;
1542 data
->repeat
= true;
1544 else if (integer_zerop (cond
) && !then_has_label
)
1546 if (warn_notreached
)
1547 remove_useless_stmts_warn_notreached (then_clause
);
1548 *stmt_p
= else_clause
;
1549 data
->repeat
= true;
1552 /* Check a couple of simple things on then/else with single stmts. */
1555 tree then_stmt
= expr_only (then_clause
);
1556 tree else_stmt
= expr_only (else_clause
);
1558 /* Notice branches to a common destination. */
1559 if (then_stmt
&& else_stmt
1560 && TREE_CODE (then_stmt
) == GOTO_EXPR
1561 && TREE_CODE (else_stmt
) == GOTO_EXPR
1562 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1564 *stmt_p
= then_stmt
;
1565 data
->repeat
= true;
1568 /* If the THEN/ELSE clause merely assigns a value to a variable or
1569 parameter which is already known to contain that value, then
1570 remove the useless THEN/ELSE clause. */
1571 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1574 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1575 && TREE_OPERAND (else_stmt
, 0) == cond
1576 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1577 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1579 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1580 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1581 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1582 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1584 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1585 ? then_stmt
: else_stmt
);
1586 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1587 ? &COND_EXPR_THEN (*stmt_p
)
1588 : &COND_EXPR_ELSE (*stmt_p
));
1591 && TREE_CODE (stmt
) == MODIFY_EXPR
1592 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1593 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1594 *location
= alloc_stmt_list ();
1598 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1599 would be re-introduced during lowering. */
1600 data
->last_goto
= NULL
;
1605 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1607 bool save_may_branch
, save_may_throw
;
1608 bool this_may_branch
, this_may_throw
;
1610 /* Collect may_branch and may_throw information for the body only. */
1611 save_may_branch
= data
->may_branch
;
1612 save_may_throw
= data
->may_throw
;
1613 data
->may_branch
= false;
1614 data
->may_throw
= false;
1615 data
->last_goto
= NULL
;
1617 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1619 this_may_branch
= data
->may_branch
;
1620 this_may_throw
= data
->may_throw
;
1621 data
->may_branch
|= save_may_branch
;
1622 data
->may_throw
|= save_may_throw
;
1623 data
->last_goto
= NULL
;
1625 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1627 /* If the body is empty, then we can emit the FINALLY block without
1628 the enclosing TRY_FINALLY_EXPR. */
1629 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1631 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1632 data
->repeat
= true;
1635 /* If the handler is empty, then we can emit the TRY block without
1636 the enclosing TRY_FINALLY_EXPR. */
1637 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1639 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1640 data
->repeat
= true;
1643 /* If the body neither throws, nor branches, then we can safely
1644 string the TRY and FINALLY blocks together. */
1645 else if (!this_may_branch
&& !this_may_throw
)
1647 tree stmt
= *stmt_p
;
1648 *stmt_p
= TREE_OPERAND (stmt
, 0);
1649 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1650 data
->repeat
= true;
1656 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1658 bool save_may_throw
, this_may_throw
;
1659 tree_stmt_iterator i
;
1662 /* Collect may_throw information for the body only. */
1663 save_may_throw
= data
->may_throw
;
1664 data
->may_throw
= false;
1665 data
->last_goto
= NULL
;
1667 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1669 this_may_throw
= data
->may_throw
;
1670 data
->may_throw
= save_may_throw
;
1672 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1673 if (!this_may_throw
)
1675 if (warn_notreached
)
1676 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1677 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1678 data
->repeat
= true;
1682 /* Process the catch clause specially. We may be able to tell that
1683 no exceptions propagate past this point. */
1685 this_may_throw
= true;
1686 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1687 stmt
= tsi_stmt (i
);
1688 data
->last_goto
= NULL
;
1690 switch (TREE_CODE (stmt
))
1693 for (; !tsi_end_p (i
); tsi_next (&i
))
1695 stmt
= tsi_stmt (i
);
1696 /* If we catch all exceptions, then the body does not
1697 propagate exceptions past this point. */
1698 if (CATCH_TYPES (stmt
) == NULL
)
1699 this_may_throw
= false;
1700 data
->last_goto
= NULL
;
1701 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1705 case EH_FILTER_EXPR
:
1706 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1707 this_may_throw
= false;
1708 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1709 this_may_throw
= false;
1710 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1714 /* Otherwise this is a cleanup. */
1715 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1717 /* If the cleanup is empty, then we can emit the TRY block without
1718 the enclosing TRY_CATCH_EXPR. */
1719 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1721 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1722 data
->repeat
= true;
1726 data
->may_throw
|= this_may_throw
;
1731 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1735 /* First remove anything underneath the BIND_EXPR. */
1736 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1738 /* If the BIND_EXPR has no variables, then we can pull everything
1739 up one level and remove the BIND_EXPR, unless this is the toplevel
1740 BIND_EXPR for the current function or an inlined function.
1742 When this situation occurs we will want to apply this
1743 optimization again. */
1744 block
= BIND_EXPR_BLOCK (*stmt_p
);
1745 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1746 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1748 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1749 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1752 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1753 data
->repeat
= true;
1759 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1761 tree dest
= GOTO_DESTINATION (*stmt_p
);
1763 data
->may_branch
= true;
1764 data
->last_goto
= NULL
;
1766 /* Record the last goto expr, so that we can delete it if unnecessary. */
1767 if (TREE_CODE (dest
) == LABEL_DECL
)
1768 data
->last_goto
= stmt_p
;
1773 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1775 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1777 data
->has_label
= true;
1779 /* We do want to jump across non-local label receiver code. */
1780 if (DECL_NONLOCAL (label
))
1781 data
->last_goto
= NULL
;
1783 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1785 *data
->last_goto
= build_empty_stmt ();
1786 data
->repeat
= true;
1789 /* ??? Add something here to delete unused labels. */
1793 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1794 decl. This allows us to eliminate redundant or useless
1795 calls to "const" functions.
1797 Gimplifier already does the same operation, but we may notice functions
1798 being const and pure once their calls has been gimplified, so we need
1799 to update the flag. */
1802 update_call_expr_flags (tree call
)
1804 tree decl
= get_callee_fndecl (call
);
1807 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1808 TREE_SIDE_EFFECTS (call
) = 0;
1809 if (TREE_NOTHROW (decl
))
1810 TREE_NOTHROW (call
) = 1;
1814 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1817 notice_special_calls (tree t
)
1819 int flags
= call_expr_flags (t
);
1821 if (flags
& ECF_MAY_BE_ALLOCA
)
1822 current_function_calls_alloca
= true;
1823 if (flags
& ECF_RETURNS_TWICE
)
1824 current_function_calls_setjmp
= true;
1828 /* Clear flags set by notice_special_calls. Used by dead code removal
1829 to update the flags. */
1832 clear_special_calls (void)
1834 current_function_calls_alloca
= false;
1835 current_function_calls_setjmp
= false;
1840 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1844 switch (TREE_CODE (t
))
1847 remove_useless_stmts_cond (tp
, data
);
1850 case TRY_FINALLY_EXPR
:
1851 remove_useless_stmts_tf (tp
, data
);
1854 case TRY_CATCH_EXPR
:
1855 remove_useless_stmts_tc (tp
, data
);
1859 remove_useless_stmts_bind (tp
, data
);
1863 remove_useless_stmts_goto (tp
, data
);
1867 remove_useless_stmts_label (tp
, data
);
1872 data
->last_goto
= NULL
;
1873 data
->may_branch
= true;
1878 data
->last_goto
= NULL
;
1879 notice_special_calls (t
);
1880 update_call_expr_flags (t
);
1881 if (tree_could_throw_p (t
))
1882 data
->may_throw
= true;
1886 data
->last_goto
= NULL
;
1888 op
= get_call_expr_in (t
);
1891 update_call_expr_flags (op
);
1892 notice_special_calls (op
);
1894 if (tree_could_throw_p (t
))
1895 data
->may_throw
= true;
1898 case STATEMENT_LIST
:
1900 tree_stmt_iterator i
= tsi_start (t
);
1901 while (!tsi_end_p (i
))
1904 if (IS_EMPTY_STMT (t
))
1910 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1913 if (TREE_CODE (t
) == STATEMENT_LIST
)
1915 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1925 data
->last_goto
= NULL
;
1929 data
->last_goto
= NULL
;
1935 remove_useless_stmts (void)
1937 struct rus_data data
;
1939 clear_special_calls ();
1943 memset (&data
, 0, sizeof (data
));
1944 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1946 while (data
.repeat
);
1950 struct tree_opt_pass pass_remove_useless_stmts
=
1952 "useless", /* name */
1954 remove_useless_stmts
, /* execute */
1957 0, /* static_pass_number */
1959 PROP_gimple_any
, /* properties_required */
1960 0, /* properties_provided */
1961 0, /* properties_destroyed */
1962 0, /* todo_flags_start */
1963 TODO_dump_func
, /* todo_flags_finish */
1967 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1970 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1974 /* Since this block is no longer reachable, we can just delete all
1975 of its PHI nodes. */
1976 phi
= phi_nodes (bb
);
1979 tree next
= PHI_CHAIN (phi
);
1980 remove_phi_node (phi
, NULL_TREE
);
1984 /* Remove edges to BB's successors. */
1985 while (EDGE_COUNT (bb
->succs
) > 0)
1986 remove_edge (EDGE_SUCC (bb
, 0));
1990 /* Remove statements of basic block BB. */
1993 remove_bb (basic_block bb
)
1995 block_stmt_iterator i
;
1996 #ifdef USE_MAPPED_LOCATION
1997 source_location loc
= UNKNOWN_LOCATION
;
1999 source_locus loc
= 0;
2004 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2005 if (dump_flags
& TDF_DETAILS
)
2007 dump_bb (bb
, dump_file
, 0);
2008 fprintf (dump_file
, "\n");
2012 /* If we remove the header or the latch of a loop, mark the loop for
2013 removal by setting its header and latch to NULL. */
2016 struct loop
*loop
= bb
->loop_father
;
2018 if (loop
->latch
== bb
2019 || loop
->header
== bb
)
2022 loop
->header
= NULL
;
2024 /* Also clean up the information associated with the loop. Updating
2025 it would waste time. More importantly, it may refer to ssa
2026 names that were defined in other removed basic block -- these
2027 ssa names are now removed and invalid. */
2028 free_numbers_of_iterations_estimates_loop (loop
);
2032 /* Remove all the instructions in the block. */
2033 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2035 tree stmt
= bsi_stmt (i
);
2036 if (TREE_CODE (stmt
) == LABEL_EXPR
2037 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2038 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2041 block_stmt_iterator new_bsi
;
2043 /* A non-reachable non-local label may still be referenced.
2044 But it no longer needs to carry the extra semantics of
2046 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2048 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2049 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2052 new_bb
= bb
->prev_bb
;
2053 new_bsi
= bsi_start (new_bb
);
2055 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2059 /* Release SSA definitions if we are in SSA. Note that we
2060 may be called when not in SSA. For example,
2061 final_cleanup calls this function via
2062 cleanup_tree_cfg. */
2064 release_defs (stmt
);
2069 /* Don't warn for removed gotos. Gotos are often removed due to
2070 jump threading, thus resulting in bogus warnings. Not great,
2071 since this way we lose warnings for gotos in the original
2072 program that are indeed unreachable. */
2073 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2075 #ifdef USE_MAPPED_LOCATION
2076 if (EXPR_HAS_LOCATION (stmt
))
2077 loc
= EXPR_LOCATION (stmt
);
2080 t
= EXPR_LOCUS (stmt
);
2081 if (t
&& LOCATION_LINE (*t
) > 0)
2087 /* If requested, give a warning that the first statement in the
2088 block is unreachable. We walk statements backwards in the
2089 loop above, so the last statement we process is the first statement
2091 #ifdef USE_MAPPED_LOCATION
2092 if (loc
> BUILTINS_LOCATION
)
2093 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2096 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2099 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2103 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2104 predicate VAL, return the edge that will be taken out of the block.
2105 If VAL does not match a unique edge, NULL is returned. */
2108 find_taken_edge (basic_block bb
, tree val
)
2112 stmt
= last_stmt (bb
);
2115 gcc_assert (is_ctrl_stmt (stmt
));
2118 if (! is_gimple_min_invariant (val
))
2121 if (TREE_CODE (stmt
) == COND_EXPR
)
2122 return find_taken_edge_cond_expr (bb
, val
);
2124 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2125 return find_taken_edge_switch_expr (bb
, val
);
2127 if (computed_goto_p (stmt
))
2128 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2133 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2134 statement, determine which of the outgoing edges will be taken out of the
2135 block. Return NULL if either edge may be taken. */
2138 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2143 dest
= label_to_block (val
);
2146 e
= find_edge (bb
, dest
);
2147 gcc_assert (e
!= NULL
);
2153 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2154 statement, determine which of the two edges will be taken out of the
2155 block. Return NULL if either edge may be taken. */
2158 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2160 edge true_edge
, false_edge
;
2162 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2164 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2165 return (zero_p (val
) ? false_edge
: true_edge
);
2168 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2169 statement, determine which edge will be taken out of the block. Return
2170 NULL if any edge may be taken. */
2173 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2175 tree switch_expr
, taken_case
;
2176 basic_block dest_bb
;
2179 switch_expr
= last_stmt (bb
);
2180 taken_case
= find_case_label_for_value (switch_expr
, val
);
2181 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2183 e
= find_edge (bb
, dest_bb
);
2189 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2190 We can make optimal use here of the fact that the case labels are
2191 sorted: We can do a binary search for a case matching VAL. */
2194 find_case_label_for_value (tree switch_expr
, tree val
)
2196 tree vec
= SWITCH_LABELS (switch_expr
);
2197 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2198 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2200 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2202 size_t i
= (high
+ low
) / 2;
2203 tree t
= TREE_VEC_ELT (vec
, i
);
2206 /* Cache the result of comparing CASE_LOW and val. */
2207 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2214 if (CASE_HIGH (t
) == NULL
)
2216 /* A singe-valued case label. */
2222 /* A case range. We can only handle integer ranges. */
2223 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2228 return default_case
;
2234 /*---------------------------------------------------------------------------
2236 ---------------------------------------------------------------------------*/
2238 /* Dump tree-specific information of block BB to file OUTF. */
2241 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2243 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2247 /* Dump a basic block on stderr. */
2250 debug_tree_bb (basic_block bb
)
2252 dump_bb (bb
, stderr
, 0);
2256 /* Dump basic block with index N on stderr. */
2259 debug_tree_bb_n (int n
)
2261 debug_tree_bb (BASIC_BLOCK (n
));
2262 return BASIC_BLOCK (n
);
2266 /* Dump the CFG on stderr.
2268 FLAGS are the same used by the tree dumping functions
2269 (see TDF_* in tree.h). */
2272 debug_tree_cfg (int flags
)
2274 dump_tree_cfg (stderr
, flags
);
2278 /* Dump the program showing basic block boundaries on the given FILE.
2280 FLAGS are the same used by the tree dumping functions (see TDF_* in
2284 dump_tree_cfg (FILE *file
, int flags
)
2286 if (flags
& TDF_DETAILS
)
2288 const char *funcname
2289 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2292 fprintf (file
, ";; Function %s\n\n", funcname
);
2293 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2294 n_basic_blocks
, n_edges
, last_basic_block
);
2296 brief_dump_cfg (file
);
2297 fprintf (file
, "\n");
2300 if (flags
& TDF_STATS
)
2301 dump_cfg_stats (file
);
2303 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2307 /* Dump CFG statistics on FILE. */
2310 dump_cfg_stats (FILE *file
)
2312 static long max_num_merged_labels
= 0;
2313 unsigned long size
, total
= 0;
2316 const char * const fmt_str
= "%-30s%-13s%12s\n";
2317 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2318 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2319 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2320 const char *funcname
2321 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2324 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2326 fprintf (file
, "---------------------------------------------------------\n");
2327 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2328 fprintf (file
, fmt_str
, "", " instances ", "used ");
2329 fprintf (file
, "---------------------------------------------------------\n");
2331 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2333 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2334 SCALE (size
), LABEL (size
));
2338 num_edges
+= EDGE_COUNT (bb
->succs
);
2339 size
= num_edges
* sizeof (struct edge_def
);
2341 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2343 fprintf (file
, "---------------------------------------------------------\n");
2344 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2346 fprintf (file
, "---------------------------------------------------------\n");
2347 fprintf (file
, "\n");
2349 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2350 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2352 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2353 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2355 fprintf (file
, "\n");
2359 /* Dump CFG statistics on stderr. Keep extern so that it's always
2360 linked in the final executable. */
2363 debug_cfg_stats (void)
2365 dump_cfg_stats (stderr
);
2369 /* Dump the flowgraph to a .vcg FILE. */
2372 tree_cfg2vcg (FILE *file
)
2377 const char *funcname
2378 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2380 /* Write the file header. */
2381 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2382 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2383 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2385 /* Write blocks and edges. */
2386 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2388 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2391 if (e
->flags
& EDGE_FAKE
)
2392 fprintf (file
, " linestyle: dotted priority: 10");
2394 fprintf (file
, " linestyle: solid priority: 100");
2396 fprintf (file
, " }\n");
2402 enum tree_code head_code
, end_code
;
2403 const char *head_name
, *end_name
;
2406 tree first
= first_stmt (bb
);
2407 tree last
= last_stmt (bb
);
2411 head_code
= TREE_CODE (first
);
2412 head_name
= tree_code_name
[head_code
];
2413 head_line
= get_lineno (first
);
2416 head_name
= "no-statement";
2420 end_code
= TREE_CODE (last
);
2421 end_name
= tree_code_name
[end_code
];
2422 end_line
= get_lineno (last
);
2425 end_name
= "no-statement";
2427 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2428 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2431 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2433 if (e
->dest
== EXIT_BLOCK_PTR
)
2434 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2436 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2438 if (e
->flags
& EDGE_FAKE
)
2439 fprintf (file
, " priority: 10 linestyle: dotted");
2441 fprintf (file
, " priority: 100 linestyle: solid");
2443 fprintf (file
, " }\n");
2446 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2450 fputs ("}\n\n", file
);
2455 /*---------------------------------------------------------------------------
2456 Miscellaneous helpers
2457 ---------------------------------------------------------------------------*/
2459 /* Return true if T represents a stmt that always transfers control. */
2462 is_ctrl_stmt (tree t
)
2464 return (TREE_CODE (t
) == COND_EXPR
2465 || TREE_CODE (t
) == SWITCH_EXPR
2466 || TREE_CODE (t
) == GOTO_EXPR
2467 || TREE_CODE (t
) == RETURN_EXPR
2468 || TREE_CODE (t
) == RESX_EXPR
);
2472 /* Return true if T is a statement that may alter the flow of control
2473 (e.g., a call to a non-returning function). */
2476 is_ctrl_altering_stmt (tree t
)
2481 call
= get_call_expr_in (t
);
2484 /* A non-pure/const CALL_EXPR alters flow control if the current
2485 function has nonlocal labels. */
2486 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2489 /* A CALL_EXPR also alters control flow if it does not return. */
2490 if (call_expr_flags (call
) & ECF_NORETURN
)
2494 /* If a statement can throw, it alters control flow. */
2495 return tree_can_throw_internal (t
);
2499 /* Return true if T is a computed goto. */
2502 computed_goto_p (tree t
)
2504 return (TREE_CODE (t
) == GOTO_EXPR
2505 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2509 /* Checks whether EXPR is a simple local goto. */
2512 simple_goto_p (tree expr
)
2514 return (TREE_CODE (expr
) == GOTO_EXPR
2515 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2519 /* Return true if T should start a new basic block. PREV_T is the
2520 statement preceding T. It is used when T is a label or a case label.
2521 Labels should only start a new basic block if their previous statement
2522 wasn't a label. Otherwise, sequence of labels would generate
2523 unnecessary basic blocks that only contain a single label. */
2526 stmt_starts_bb_p (tree t
, tree prev_t
)
2531 /* LABEL_EXPRs start a new basic block only if the preceding
2532 statement wasn't a label of the same type. This prevents the
2533 creation of consecutive blocks that have nothing but a single
2535 if (TREE_CODE (t
) == LABEL_EXPR
)
2537 /* Nonlocal and computed GOTO targets always start a new block. */
2538 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2539 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2542 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2544 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2547 cfg_stats
.num_merged_labels
++;
2558 /* Return true if T should end a basic block. */
2561 stmt_ends_bb_p (tree t
)
2563 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2567 /* Add gotos that used to be represented implicitly in the CFG. */
2570 disband_implicit_edges (void)
2573 block_stmt_iterator last
;
2580 last
= bsi_last (bb
);
2581 stmt
= last_stmt (bb
);
2583 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2585 /* Remove superfluous gotos from COND_EXPR branches. Moved
2586 from cfg_remove_useless_stmts here since it violates the
2587 invariants for tree--cfg correspondence and thus fits better
2588 here where we do it anyway. */
2589 e
= find_edge (bb
, bb
->next_bb
);
2592 if (e
->flags
& EDGE_TRUE_VALUE
)
2593 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2594 else if (e
->flags
& EDGE_FALSE_VALUE
)
2595 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2598 e
->flags
|= EDGE_FALLTHRU
;
2604 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2606 /* Remove the RETURN_EXPR if we may fall though to the exit
2608 gcc_assert (single_succ_p (bb
));
2609 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2611 if (bb
->next_bb
== EXIT_BLOCK_PTR
2612 && !TREE_OPERAND (stmt
, 0))
2615 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2620 /* There can be no fallthru edge if the last statement is a control
2622 if (stmt
&& is_ctrl_stmt (stmt
))
2625 /* Find a fallthru edge and emit the goto if necessary. */
2626 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2627 if (e
->flags
& EDGE_FALLTHRU
)
2630 if (!e
|| e
->dest
== bb
->next_bb
)
2633 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2634 label
= tree_block_label (e
->dest
);
2636 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2637 #ifdef USE_MAPPED_LOCATION
2638 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2640 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2642 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2643 e
->flags
&= ~EDGE_FALLTHRU
;
2647 /* Remove block annotations and other datastructures. */
2650 delete_tree_cfg_annotations (void)
2652 label_to_block_map
= NULL
;
2656 /* Return the first statement in basic block BB. */
2659 first_stmt (basic_block bb
)
2661 block_stmt_iterator i
= bsi_start (bb
);
2662 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2666 /* Return the last statement in basic block BB. */
2669 last_stmt (basic_block bb
)
2671 block_stmt_iterator b
= bsi_last (bb
);
2672 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2676 /* Return a pointer to the last statement in block BB. */
2679 last_stmt_ptr (basic_block bb
)
2681 block_stmt_iterator last
= bsi_last (bb
);
2682 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2686 /* Return the last statement of an otherwise empty block. Return NULL
2687 if the block is totally empty, or if it contains more than one
2691 last_and_only_stmt (basic_block bb
)
2693 block_stmt_iterator i
= bsi_last (bb
);
2699 last
= bsi_stmt (i
);
2704 /* Empty statements should no longer appear in the instruction stream.
2705 Everything that might have appeared before should be deleted by
2706 remove_useless_stmts, and the optimizers should just bsi_remove
2707 instead of smashing with build_empty_stmt.
2709 Thus the only thing that should appear here in a block containing
2710 one executable statement is a label. */
2711 prev
= bsi_stmt (i
);
2712 if (TREE_CODE (prev
) == LABEL_EXPR
)
2719 /* Mark BB as the basic block holding statement T. */
2722 set_bb_for_stmt (tree t
, basic_block bb
)
2724 if (TREE_CODE (t
) == PHI_NODE
)
2726 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2728 tree_stmt_iterator i
;
2729 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2730 set_bb_for_stmt (tsi_stmt (i
), bb
);
2734 stmt_ann_t ann
= get_stmt_ann (t
);
2737 /* If the statement is a label, add the label to block-to-labels map
2738 so that we can speed up edge creation for GOTO_EXPRs. */
2739 if (TREE_CODE (t
) == LABEL_EXPR
)
2743 t
= LABEL_EXPR_LABEL (t
);
2744 uid
= LABEL_DECL_UID (t
);
2747 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2748 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2749 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2752 /* We're moving an existing label. Make sure that we've
2753 removed it from the old block. */
2754 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2755 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2760 /* Finds iterator for STMT. */
2762 extern block_stmt_iterator
2763 bsi_for_stmt (tree stmt
)
2765 block_stmt_iterator bsi
;
2767 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2768 if (bsi_stmt (bsi
) == stmt
)
2774 /* Mark statement T as modified, and update it. */
2776 update_modified_stmts (tree t
)
2778 if (TREE_CODE (t
) == STATEMENT_LIST
)
2780 tree_stmt_iterator i
;
2782 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2784 stmt
= tsi_stmt (i
);
2785 update_stmt_if_modified (stmt
);
2789 update_stmt_if_modified (t
);
2792 /* Insert statement (or statement list) T before the statement
2793 pointed-to by iterator I. M specifies how to update iterator I
2794 after insertion (see enum bsi_iterator_update). */
2797 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2799 set_bb_for_stmt (t
, i
->bb
);
2800 update_modified_stmts (t
);
2801 tsi_link_before (&i
->tsi
, t
, m
);
2805 /* Insert statement (or statement list) T after the statement
2806 pointed-to by iterator I. M specifies how to update iterator I
2807 after insertion (see enum bsi_iterator_update). */
2810 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2812 set_bb_for_stmt (t
, i
->bb
);
2813 update_modified_stmts (t
);
2814 tsi_link_after (&i
->tsi
, t
, m
);
2818 /* Remove the statement pointed to by iterator I. The iterator is updated
2819 to the next statement. */
2822 bsi_remove (block_stmt_iterator
*i
)
2824 tree t
= bsi_stmt (*i
);
2825 set_bb_for_stmt (t
, NULL
);
2826 delink_stmt_imm_use (t
);
2827 tsi_delink (&i
->tsi
);
2828 mark_stmt_modified (t
);
2832 /* Move the statement at FROM so it comes right after the statement at TO. */
2835 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2837 tree stmt
= bsi_stmt (*from
);
2839 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2843 /* Move the statement at FROM so it comes right before the statement at TO. */
2846 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2848 tree stmt
= bsi_stmt (*from
);
2850 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2854 /* Move the statement at FROM to the end of basic block BB. */
2857 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2859 block_stmt_iterator last
= bsi_last (bb
);
2861 /* Have to check bsi_end_p because it could be an empty block. */
2862 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2863 bsi_move_before (from
, &last
);
2865 bsi_move_after (from
, &last
);
2869 /* Replace the contents of the statement pointed to by iterator BSI
2870 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2871 information of the original statement is preserved. */
2874 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2877 tree orig_stmt
= bsi_stmt (*bsi
);
2879 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2880 set_bb_for_stmt (stmt
, bsi
->bb
);
2882 /* Preserve EH region information from the original statement, if
2883 requested by the caller. */
2884 if (preserve_eh_info
)
2886 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2888 add_stmt_to_eh_region (stmt
, eh_region
);
2891 delink_stmt_imm_use (orig_stmt
);
2892 *bsi_stmt_ptr (*bsi
) = stmt
;
2893 mark_stmt_modified (stmt
);
2894 update_modified_stmts (stmt
);
2898 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2899 is made to place the statement in an existing basic block, but
2900 sometimes that isn't possible. When it isn't possible, the edge is
2901 split and the statement is added to the new block.
2903 In all cases, the returned *BSI points to the correct location. The
2904 return value is true if insertion should be done after the location,
2905 or false if it should be done before the location. If new basic block
2906 has to be created, it is stored in *NEW_BB. */
2909 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2910 basic_block
*new_bb
)
2912 basic_block dest
, src
;
2918 /* If the destination has one predecessor which has no PHI nodes,
2919 insert there. Except for the exit block.
2921 The requirement for no PHI nodes could be relaxed. Basically we
2922 would have to examine the PHIs to prove that none of them used
2923 the value set by the statement we want to insert on E. That
2924 hardly seems worth the effort. */
2925 if (single_pred_p (dest
)
2926 && ! phi_nodes (dest
)
2927 && dest
!= EXIT_BLOCK_PTR
)
2929 *bsi
= bsi_start (dest
);
2930 if (bsi_end_p (*bsi
))
2933 /* Make sure we insert after any leading labels. */
2934 tmp
= bsi_stmt (*bsi
);
2935 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2938 if (bsi_end_p (*bsi
))
2940 tmp
= bsi_stmt (*bsi
);
2943 if (bsi_end_p (*bsi
))
2945 *bsi
= bsi_last (dest
);
2952 /* If the source has one successor, the edge is not abnormal and
2953 the last statement does not end a basic block, insert there.
2954 Except for the entry block. */
2956 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2957 && single_succ_p (src
)
2958 && src
!= ENTRY_BLOCK_PTR
)
2960 *bsi
= bsi_last (src
);
2961 if (bsi_end_p (*bsi
))
2964 tmp
= bsi_stmt (*bsi
);
2965 if (!stmt_ends_bb_p (tmp
))
2968 /* Insert code just before returning the value. We may need to decompose
2969 the return in the case it contains non-trivial operand. */
2970 if (TREE_CODE (tmp
) == RETURN_EXPR
)
2972 tree op
= TREE_OPERAND (tmp
, 0);
2973 if (!is_gimple_val (op
))
2975 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
2976 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
2977 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
2984 /* Otherwise, create a new basic block, and split this edge. */
2985 dest
= split_edge (e
);
2988 e
= single_pred_edge (dest
);
2993 /* This routine will commit all pending edge insertions, creating any new
2994 basic blocks which are necessary. */
2997 bsi_commit_edge_inserts (void)
3003 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3006 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3007 bsi_commit_one_edge_insert (e
, NULL
);
3011 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3012 to this block, otherwise set it to NULL. */
3015 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3019 if (PENDING_STMT (e
))
3021 block_stmt_iterator bsi
;
3022 tree stmt
= PENDING_STMT (e
);
3024 PENDING_STMT (e
) = NULL_TREE
;
3026 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3027 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3029 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3034 /* Add STMT to the pending list of edge E. No actual insertion is
3035 made until a call to bsi_commit_edge_inserts () is made. */
3038 bsi_insert_on_edge (edge e
, tree stmt
)
3040 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3043 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3044 block has to be created, it is returned. */
3047 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3049 block_stmt_iterator bsi
;
3050 basic_block new_bb
= NULL
;
3052 gcc_assert (!PENDING_STMT (e
));
3054 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3055 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3057 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3062 /*---------------------------------------------------------------------------
3063 Tree specific functions for CFG manipulation
3064 ---------------------------------------------------------------------------*/
3066 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3069 reinstall_phi_args (edge new_edge
, edge old_edge
)
3073 if (!PENDING_STMT (old_edge
))
3076 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3078 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3080 tree result
= TREE_PURPOSE (var
);
3081 tree arg
= TREE_VALUE (var
);
3083 gcc_assert (result
== PHI_RESULT (phi
));
3085 add_phi_arg (phi
, arg
, new_edge
);
3088 PENDING_STMT (old_edge
) = NULL
;
3091 /* Returns the basic block after that the new basic block created
3092 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3093 near its "logical" location. This is of most help to humans looking
3094 at debugging dumps. */
3097 split_edge_bb_loc (edge edge_in
)
3099 basic_block dest
= edge_in
->dest
;
3101 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3102 return edge_in
->src
;
3104 return dest
->prev_bb
;
3107 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3108 Abort on abnormal edges. */
3111 tree_split_edge (edge edge_in
)
3113 basic_block new_bb
, after_bb
, dest
, src
;
3116 /* Abnormal edges cannot be split. */
3117 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3120 dest
= edge_in
->dest
;
3122 after_bb
= split_edge_bb_loc (edge_in
);
3124 new_bb
= create_empty_bb (after_bb
);
3125 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3126 new_bb
->count
= edge_in
->count
;
3127 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3128 new_edge
->probability
= REG_BR_PROB_BASE
;
3129 new_edge
->count
= edge_in
->count
;
3131 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3133 reinstall_phi_args (new_edge
, e
);
3139 /* Return true when BB has label LABEL in it. */
3142 has_label_p (basic_block bb
, tree label
)
3144 block_stmt_iterator bsi
;
3146 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3148 tree stmt
= bsi_stmt (bsi
);
3150 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3152 if (LABEL_EXPR_LABEL (stmt
) == label
)
3159 /* Callback for walk_tree, check that all elements with address taken are
3160 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3161 inside a PHI node. */
3164 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3167 bool in_phi
= (data
!= NULL
);
3172 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3173 #define CHECK_OP(N, MSG) \
3174 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3175 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3177 switch (TREE_CODE (t
))
3180 if (SSA_NAME_IN_FREE_LIST (t
))
3182 error ("SSA name in freelist but still referenced");
3188 x
= fold (ASSERT_EXPR_COND (t
));
3189 if (x
== boolean_false_node
)
3191 error ("ASSERT_EXPR with an always-false condition");
3197 x
= TREE_OPERAND (t
, 0);
3198 if (TREE_CODE (x
) == BIT_FIELD_REF
3199 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3201 error ("GIMPLE register modified with BIT_FIELD_REF");
3210 bool old_side_effects
;
3213 bool new_side_effects
;
3215 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3216 dead PHIs that take the address of something. But if the PHI
3217 result is dead, the fact that it takes the address of anything
3218 is irrelevant. Because we can not tell from here if a PHI result
3219 is dead, we just skip this check for PHIs altogether. This means
3220 we may be missing "valid" checks, but what can you do?
3221 This was PR19217. */
3225 old_invariant
= TREE_INVARIANT (t
);
3226 old_constant
= TREE_CONSTANT (t
);
3227 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3229 recompute_tree_invarant_for_addr_expr (t
);
3230 new_invariant
= TREE_INVARIANT (t
);
3231 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3232 new_constant
= TREE_CONSTANT (t
);
3234 if (old_invariant
!= new_invariant
)
3236 error ("invariant not recomputed when ADDR_EXPR changed");
3240 if (old_constant
!= new_constant
)
3242 error ("constant not recomputed when ADDR_EXPR changed");
3245 if (old_side_effects
!= new_side_effects
)
3247 error ("side effects not recomputed when ADDR_EXPR changed");
3251 /* Skip any references (they will be checked when we recurse down the
3252 tree) and ensure that any variable used as a prefix is marked
3254 for (x
= TREE_OPERAND (t
, 0);
3255 handled_component_p (x
);
3256 x
= TREE_OPERAND (x
, 0))
3259 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3261 if (!TREE_ADDRESSABLE (x
))
3263 error ("address taken, but ADDRESSABLE bit not set");
3270 x
= COND_EXPR_COND (t
);
3271 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3273 error ("non-boolean used in condition");
3276 if (!is_gimple_condexpr (x
))
3278 error ("invalid conditional operand");
3285 case FIX_TRUNC_EXPR
:
3287 case FIX_FLOOR_EXPR
:
3288 case FIX_ROUND_EXPR
:
3293 case NON_LVALUE_EXPR
:
3294 case TRUTH_NOT_EXPR
:
3295 CHECK_OP (0, "invalid operand to unary operator");
3302 case ARRAY_RANGE_REF
:
3304 case VIEW_CONVERT_EXPR
:
3305 /* We have a nest of references. Verify that each of the operands
3306 that determine where to reference is either a constant or a variable,
3307 verify that the base is valid, and then show we've already checked
3309 while (handled_component_p (t
))
3311 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3312 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3313 else if (TREE_CODE (t
) == ARRAY_REF
3314 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3316 CHECK_OP (1, "invalid array index");
3317 if (TREE_OPERAND (t
, 2))
3318 CHECK_OP (2, "invalid array lower bound");
3319 if (TREE_OPERAND (t
, 3))
3320 CHECK_OP (3, "invalid array stride");
3322 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3324 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3325 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3328 t
= TREE_OPERAND (t
, 0);
3331 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3333 error ("invalid reference prefix");
3345 case UNORDERED_EXPR
:
3356 case TRUNC_DIV_EXPR
:
3358 case FLOOR_DIV_EXPR
:
3359 case ROUND_DIV_EXPR
:
3360 case TRUNC_MOD_EXPR
:
3362 case FLOOR_MOD_EXPR
:
3363 case ROUND_MOD_EXPR
:
3365 case EXACT_DIV_EXPR
:
3375 CHECK_OP (0, "invalid operand to binary operator");
3376 CHECK_OP (1, "invalid operand to binary operator");
3388 /* Verify STMT, return true if STMT is not in GIMPLE form.
3389 TODO: Implement type checking. */
3392 verify_stmt (tree stmt
, bool last_in_block
)
3396 if (!is_gimple_stmt (stmt
))
3398 error ("is not a valid GIMPLE statement");
3402 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3405 debug_generic_stmt (addr
);
3409 /* If the statement is marked as part of an EH region, then it is
3410 expected that the statement could throw. Verify that when we
3411 have optimizations that simplify statements such that we prove
3412 that they cannot throw, that we update other data structures
3414 if (lookup_stmt_eh_region (stmt
) >= 0)
3416 if (!tree_could_throw_p (stmt
))
3418 error ("statement marked for throw, but doesn%'t");
3421 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3423 error ("statement marked for throw in middle of block");
3431 debug_generic_stmt (stmt
);
3436 /* Return true when the T can be shared. */
3439 tree_node_can_be_shared (tree t
)
3441 if (IS_TYPE_OR_DECL_P (t
)
3442 /* We check for constants explicitly since they are not considered
3443 gimple invariants if they overflowed. */
3444 || CONSTANT_CLASS_P (t
)
3445 || is_gimple_min_invariant (t
)
3446 || TREE_CODE (t
) == SSA_NAME
3447 || t
== error_mark_node
)
3450 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3453 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3454 /* We check for constants explicitly since they are not considered
3455 gimple invariants if they overflowed. */
3456 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3457 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3458 || (TREE_CODE (t
) == COMPONENT_REF
3459 || TREE_CODE (t
) == REALPART_EXPR
3460 || TREE_CODE (t
) == IMAGPART_EXPR
))
3461 t
= TREE_OPERAND (t
, 0);
3470 /* Called via walk_trees. Verify tree sharing. */
3473 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3475 htab_t htab
= (htab_t
) data
;
3478 if (tree_node_can_be_shared (*tp
))
3480 *walk_subtrees
= false;
3484 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3493 /* Verify the GIMPLE statement chain. */
3499 block_stmt_iterator bsi
;
3504 timevar_push (TV_TREE_STMT_VERIFY
);
3505 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3512 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3514 int phi_num_args
= PHI_NUM_ARGS (phi
);
3516 if (bb_for_stmt (phi
) != bb
)
3518 error ("bb_for_stmt (phi) is set to a wrong basic block");
3522 for (i
= 0; i
< phi_num_args
; i
++)
3524 tree t
= PHI_ARG_DEF (phi
, i
);
3527 /* Addressable variables do have SSA_NAMEs but they
3528 are not considered gimple values. */
3529 if (TREE_CODE (t
) != SSA_NAME
3530 && TREE_CODE (t
) != FUNCTION_DECL
3531 && !is_gimple_val (t
))
3533 error ("PHI def is not a GIMPLE value");
3534 debug_generic_stmt (phi
);
3535 debug_generic_stmt (t
);
3539 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3542 debug_generic_stmt (addr
);
3546 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3549 error ("incorrect sharing of tree nodes");
3550 debug_generic_stmt (phi
);
3551 debug_generic_stmt (addr
);
3557 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3559 tree stmt
= bsi_stmt (bsi
);
3561 if (bb_for_stmt (stmt
) != bb
)
3563 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3568 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3569 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3572 error ("incorrect sharing of tree nodes");
3573 debug_generic_stmt (stmt
);
3574 debug_generic_stmt (addr
);
3581 internal_error ("verify_stmts failed");
3584 timevar_pop (TV_TREE_STMT_VERIFY
);
3588 /* Verifies that the flow information is OK. */
3591 tree_verify_flow_info (void)
3595 block_stmt_iterator bsi
;
3600 if (ENTRY_BLOCK_PTR
->stmt_list
)
3602 error ("ENTRY_BLOCK has a statement list associated with it");
3606 if (EXIT_BLOCK_PTR
->stmt_list
)
3608 error ("EXIT_BLOCK has a statement list associated with it");
3612 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3613 if (e
->flags
& EDGE_FALLTHRU
)
3615 error ("fallthru to exit from bb %d", e
->src
->index
);
3621 bool found_ctrl_stmt
= false;
3625 /* Skip labels on the start of basic block. */
3626 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3628 tree prev_stmt
= stmt
;
3630 stmt
= bsi_stmt (bsi
);
3632 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3635 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3637 error ("nonlocal label %s is not first "
3638 "in a sequence of labels in bb %d",
3639 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3644 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3646 error ("label %s to block does not match in bb %d",
3647 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3652 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3653 != current_function_decl
)
3655 error ("label %s has incorrect context in bb %d",
3656 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3662 /* Verify that body of basic block BB is free of control flow. */
3663 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3665 tree stmt
= bsi_stmt (bsi
);
3667 if (found_ctrl_stmt
)
3669 error ("control flow in the middle of basic block %d",
3674 if (stmt_ends_bb_p (stmt
))
3675 found_ctrl_stmt
= true;
3677 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3679 error ("label %s in the middle of basic block %d",
3680 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3685 bsi
= bsi_last (bb
);
3686 if (bsi_end_p (bsi
))
3689 stmt
= bsi_stmt (bsi
);
3691 err
|= verify_eh_edges (stmt
);
3693 if (is_ctrl_stmt (stmt
))
3695 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3696 if (e
->flags
& EDGE_FALLTHRU
)
3698 error ("fallthru edge after a control statement in bb %d",
3704 switch (TREE_CODE (stmt
))
3710 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3711 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3713 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3717 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3719 if (!true_edge
|| !false_edge
3720 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3721 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3722 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3723 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3724 || EDGE_COUNT (bb
->succs
) >= 3)
3726 error ("wrong outgoing edge flags at end of bb %d",
3731 if (!has_label_p (true_edge
->dest
,
3732 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3734 error ("%<then%> label does not match edge at end of bb %d",
3739 if (!has_label_p (false_edge
->dest
,
3740 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3742 error ("%<else%> label does not match edge at end of bb %d",
3750 if (simple_goto_p (stmt
))
3752 error ("explicit goto at end of bb %d", bb
->index
);
3757 /* FIXME. We should double check that the labels in the
3758 destination blocks have their address taken. */
3759 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3760 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3761 | EDGE_FALSE_VALUE
))
3762 || !(e
->flags
& EDGE_ABNORMAL
))
3764 error ("wrong outgoing edge flags at end of bb %d",
3772 if (!single_succ_p (bb
)
3773 || (single_succ_edge (bb
)->flags
3774 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3775 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3777 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3780 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3782 error ("return edge does not point to exit in bb %d",
3795 vec
= SWITCH_LABELS (stmt
);
3796 n
= TREE_VEC_LENGTH (vec
);
3798 /* Mark all the destination basic blocks. */
3799 for (i
= 0; i
< n
; ++i
)
3801 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3802 basic_block label_bb
= label_to_block (lab
);
3804 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3805 label_bb
->aux
= (void *)1;
3808 /* Verify that the case labels are sorted. */
3809 prev
= TREE_VEC_ELT (vec
, 0);
3810 for (i
= 1; i
< n
- 1; ++i
)
3812 tree c
= TREE_VEC_ELT (vec
, i
);
3815 error ("found default case not at end of case vector");
3819 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3821 error ("case labels not sorted:");
3822 print_generic_expr (stderr
, prev
, 0);
3823 fprintf (stderr
," is greater than ");
3824 print_generic_expr (stderr
, c
, 0);
3825 fprintf (stderr
," but comes before it.\n");
3830 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3832 error ("no default case found at end of case vector");
3836 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3840 error ("extra outgoing edge %d->%d",
3841 bb
->index
, e
->dest
->index
);
3844 e
->dest
->aux
= (void *)2;
3845 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3846 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3848 error ("wrong outgoing edge flags at end of bb %d",
3854 /* Check that we have all of them. */
3855 for (i
= 0; i
< n
; ++i
)
3857 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3858 basic_block label_bb
= label_to_block (lab
);
3860 if (label_bb
->aux
!= (void *)2)
3862 error ("missing edge %i->%i",
3863 bb
->index
, label_bb
->index
);
3868 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3869 e
->dest
->aux
= (void *)0;
3876 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3877 verify_dominators (CDI_DOMINATORS
);
3883 /* Updates phi nodes after creating a forwarder block joined
3884 by edge FALLTHRU. */
3887 tree_make_forwarder_block (edge fallthru
)
3891 basic_block dummy
, bb
;
3892 tree phi
, new_phi
, var
;
3894 dummy
= fallthru
->src
;
3895 bb
= fallthru
->dest
;
3897 if (single_pred_p (bb
))
3900 /* If we redirected a branch we must create new phi nodes at the
3902 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3904 var
= PHI_RESULT (phi
);
3905 new_phi
= create_phi_node (var
, bb
);
3906 SSA_NAME_DEF_STMT (var
) = new_phi
;
3907 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3908 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3911 /* Ensure that the PHI node chain is in the same order. */
3912 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3914 /* Add the arguments we have stored on edges. */
3915 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3920 flush_pending_stmts (e
);
3925 /* Return a non-special label in the head of basic block BLOCK.
3926 Create one if it doesn't exist. */
3929 tree_block_label (basic_block bb
)
3931 block_stmt_iterator i
, s
= bsi_start (bb
);
3935 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3937 stmt
= bsi_stmt (i
);
3938 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3940 label
= LABEL_EXPR_LABEL (stmt
);
3941 if (!DECL_NONLOCAL (label
))
3944 bsi_move_before (&i
, &s
);
3949 label
= create_artificial_label ();
3950 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3951 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3956 /* Attempt to perform edge redirection by replacing a possibly complex
3957 jump instruction by a goto or by removing the jump completely.
3958 This can apply only if all edges now point to the same block. The
3959 parameters and return values are equivalent to
3960 redirect_edge_and_branch. */
3963 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
3965 basic_block src
= e
->src
;
3966 block_stmt_iterator b
;
3969 /* We can replace or remove a complex jump only when we have exactly
3971 if (EDGE_COUNT (src
->succs
) != 2
3972 /* Verify that all targets will be TARGET. Specifically, the
3973 edge that is not E must also go to TARGET. */
3974 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
3980 stmt
= bsi_stmt (b
);
3982 if (TREE_CODE (stmt
) == COND_EXPR
3983 || TREE_CODE (stmt
) == SWITCH_EXPR
)
3986 e
= ssa_redirect_edge (e
, target
);
3987 e
->flags
= EDGE_FALLTHRU
;
3995 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3996 edge representing the redirected branch. */
3999 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4001 basic_block bb
= e
->src
;
4002 block_stmt_iterator bsi
;
4006 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4009 if (e
->src
!= ENTRY_BLOCK_PTR
4010 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4013 if (e
->dest
== dest
)
4016 label
= tree_block_label (dest
);
4018 bsi
= bsi_last (bb
);
4019 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4021 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4024 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4025 ? COND_EXPR_THEN (stmt
)
4026 : COND_EXPR_ELSE (stmt
));
4027 GOTO_DESTINATION (stmt
) = label
;
4031 /* No non-abnormal edges should lead from a non-simple goto, and
4032 simple ones should be represented implicitly. */
4037 tree cases
= get_cases_for_edge (e
, stmt
);
4039 /* If we have a list of cases associated with E, then use it
4040 as it's a lot faster than walking the entire case vector. */
4043 edge e2
= find_edge (e
->src
, dest
);
4050 CASE_LABEL (cases
) = label
;
4051 cases
= TREE_CHAIN (cases
);
4054 /* If there was already an edge in the CFG, then we need
4055 to move all the cases associated with E to E2. */
4058 tree cases2
= get_cases_for_edge (e2
, stmt
);
4060 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4061 TREE_CHAIN (cases2
) = first
;
4066 tree vec
= SWITCH_LABELS (stmt
);
4067 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4069 for (i
= 0; i
< n
; i
++)
4071 tree elt
= TREE_VEC_ELT (vec
, i
);
4073 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4074 CASE_LABEL (elt
) = label
;
4083 e
->flags
|= EDGE_FALLTHRU
;
4087 /* Otherwise it must be a fallthru edge, and we don't need to
4088 do anything besides redirecting it. */
4089 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4093 /* Update/insert PHI nodes as necessary. */
4095 /* Now update the edges in the CFG. */
4096 e
= ssa_redirect_edge (e
, dest
);
4102 /* Simple wrapper, as we can always redirect fallthru edges. */
4105 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4107 e
= tree_redirect_edge_and_branch (e
, dest
);
4114 /* Splits basic block BB after statement STMT (but at least after the
4115 labels). If STMT is NULL, BB is split just after the labels. */
4118 tree_split_block (basic_block bb
, void *stmt
)
4120 block_stmt_iterator bsi
, bsi_tgt
;
4126 new_bb
= create_empty_bb (bb
);
4128 /* Redirect the outgoing edges. */
4129 new_bb
->succs
= bb
->succs
;
4131 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4134 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4137 /* Move everything from BSI to the new basic block. */
4138 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4140 act
= bsi_stmt (bsi
);
4141 if (TREE_CODE (act
) == LABEL_EXPR
)
4154 bsi_tgt
= bsi_start (new_bb
);
4155 while (!bsi_end_p (bsi
))
4157 act
= bsi_stmt (bsi
);
4159 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4166 /* Moves basic block BB after block AFTER. */
4169 tree_move_block_after (basic_block bb
, basic_block after
)
4171 if (bb
->prev_bb
== after
)
4175 link_block (bb
, after
);
4181 /* Return true if basic_block can be duplicated. */
4184 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4190 /* Create a duplicate of the basic block BB. NOTE: This does not
4191 preserve SSA form. */
4194 tree_duplicate_bb (basic_block bb
)
4197 block_stmt_iterator bsi
, bsi_tgt
;
4200 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4202 /* Copy the PHI nodes. We ignore PHI node arguments here because
4203 the incoming edges have not been setup yet. */
4204 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4206 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4207 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4210 /* Keep the chain of PHI nodes in the same order so that they can be
4211 updated by ssa_redirect_edge. */
4212 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4214 bsi_tgt
= bsi_start (new_bb
);
4215 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4217 def_operand_p def_p
;
4218 ssa_op_iter op_iter
;
4222 stmt
= bsi_stmt (bsi
);
4223 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4226 /* Create a new copy of STMT and duplicate STMT's virtual
4228 copy
= unshare_expr (stmt
);
4229 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4230 copy_virtual_operands (copy
, stmt
);
4231 region
= lookup_stmt_eh_region (stmt
);
4233 add_stmt_to_eh_region (copy
, region
);
4235 /* Create new names for all the definitions created by COPY and
4236 add replacement mappings for each new name. */
4237 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4238 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4245 /* Basic block BB_COPY was created by code duplication. Add phi node
4246 arguments for edges going out of BB_COPY. The blocks that were
4247 duplicated have BB_DUPLICATED set. */
4250 add_phi_args_after_copy_bb (basic_block bb_copy
)
4252 basic_block bb
, dest
;
4255 tree phi
, phi_copy
, phi_next
, def
;
4257 bb
= get_bb_original (bb_copy
);
4259 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4261 if (!phi_nodes (e_copy
->dest
))
4264 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4265 dest
= get_bb_original (e_copy
->dest
);
4267 dest
= e_copy
->dest
;
4269 e
= find_edge (bb
, dest
);
4272 /* During loop unrolling the target of the latch edge is copied.
4273 In this case we are not looking for edge to dest, but to
4274 duplicated block whose original was dest. */
4275 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4276 if ((e
->dest
->flags
& BB_DUPLICATED
)
4277 && get_bb_original (e
->dest
) == dest
)
4280 gcc_assert (e
!= NULL
);
4283 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4285 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4287 phi_next
= PHI_CHAIN (phi
);
4288 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4289 add_phi_arg (phi_copy
, def
, e_copy
);
4294 /* Blocks in REGION_COPY array of length N_REGION were created by
4295 duplication of basic blocks. Add phi node arguments for edges
4296 going from these blocks. */
4299 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4303 for (i
= 0; i
< n_region
; i
++)
4304 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4306 for (i
= 0; i
< n_region
; i
++)
4307 add_phi_args_after_copy_bb (region_copy
[i
]);
4309 for (i
= 0; i
< n_region
; i
++)
4310 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4313 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4314 important exit edge EXIT. By important we mean that no SSA name defined
4315 inside region is live over the other exit edges of the region. All entry
4316 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4317 to the duplicate of the region. SSA form, dominance and loop information
4318 is updated. The new basic blocks are stored to REGION_COPY in the same
4319 order as they had in REGION, provided that REGION_COPY is not NULL.
4320 The function returns false if it is unable to copy the region,
4324 tree_duplicate_sese_region (edge entry
, edge exit
,
4325 basic_block
*region
, unsigned n_region
,
4326 basic_block
*region_copy
)
4329 bool free_region_copy
= false, copying_header
= false;
4330 struct loop
*loop
= entry
->dest
->loop_father
;
4334 int total_freq
= 0, entry_freq
= 0;
4335 gcov_type total_count
= 0, entry_count
= 0;
4337 if (!can_copy_bbs_p (region
, n_region
))
4340 /* Some sanity checking. Note that we do not check for all possible
4341 missuses of the functions. I.e. if you ask to copy something weird,
4342 it will work, but the state of structures probably will not be
4344 for (i
= 0; i
< n_region
; i
++)
4346 /* We do not handle subloops, i.e. all the blocks must belong to the
4348 if (region
[i
]->loop_father
!= loop
)
4351 if (region
[i
] != entry
->dest
4352 && region
[i
] == loop
->header
)
4358 /* In case the function is used for loop header copying (which is the primary
4359 use), ensure that EXIT and its copy will be new latch and entry edges. */
4360 if (loop
->header
== entry
->dest
)
4362 copying_header
= true;
4363 loop
->copy
= loop
->outer
;
4365 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4368 for (i
= 0; i
< n_region
; i
++)
4369 if (region
[i
] != exit
->src
4370 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4376 region_copy
= xmalloc (sizeof (basic_block
) * n_region
);
4377 free_region_copy
= true;
4380 gcc_assert (!need_ssa_update_p ());
4382 /* Record blocks outside the region that are dominated by something
4384 doms
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4385 initialize_original_copy_tables ();
4387 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4389 if (entry
->dest
->count
)
4391 total_count
= entry
->dest
->count
;
4392 entry_count
= entry
->count
;
4393 /* Fix up corner cases, to avoid division by zero or creation of negative
4395 if (entry_count
> total_count
)
4396 entry_count
= total_count
;
4400 total_freq
= entry
->dest
->frequency
;
4401 entry_freq
= EDGE_FREQUENCY (entry
);
4402 /* Fix up corner cases, to avoid division by zero or creation of negative
4404 if (total_freq
== 0)
4406 else if (entry_freq
> total_freq
)
4407 entry_freq
= total_freq
;
4410 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4411 split_edge_bb_loc (entry
));
4414 scale_bbs_frequencies_gcov_type (region
, n_region
,
4415 total_count
- entry_count
,
4417 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4422 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4424 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4429 loop
->header
= exit
->dest
;
4430 loop
->latch
= exit
->src
;
4433 /* Redirect the entry and add the phi node arguments. */
4434 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4435 gcc_assert (redirected
!= NULL
);
4436 flush_pending_stmts (entry
);
4438 /* Concerning updating of dominators: We must recount dominators
4439 for entry block and its copy. Anything that is outside of the
4440 region, but was dominated by something inside needs recounting as
4442 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4443 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4444 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4447 /* Add the other PHI node arguments. */
4448 add_phi_args_after_copy (region_copy
, n_region
);
4450 /* Update the SSA web. */
4451 update_ssa (TODO_update_ssa
);
4453 if (free_region_copy
)
4456 free_original_copy_tables ();
4461 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4464 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4466 tree arg
, vars
, var
;
4467 bool ignore_topmost_bind
= false, any_var
= false;
4471 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4473 arg
= DECL_ARGUMENTS (fn
);
4476 print_generic_expr (file
, arg
, dump_flags
);
4477 if (TREE_CHAIN (arg
))
4478 fprintf (file
, ", ");
4479 arg
= TREE_CHAIN (arg
);
4481 fprintf (file
, ")\n");
4483 if (flags
& TDF_DETAILS
)
4484 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4485 if (flags
& TDF_RAW
)
4487 dump_node (fn
, TDF_SLIM
| flags
, file
);
4491 /* When GIMPLE is lowered, the variables are no longer available in
4492 BIND_EXPRs, so display them separately. */
4493 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4495 ignore_topmost_bind
= true;
4497 fprintf (file
, "{\n");
4498 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4500 var
= TREE_VALUE (vars
);
4502 print_generic_decl (file
, var
, flags
);
4503 fprintf (file
, "\n");
4509 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4511 /* Make a CFG based dump. */
4512 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4513 if (!ignore_topmost_bind
)
4514 fprintf (file
, "{\n");
4516 if (any_var
&& n_basic_blocks
)
4517 fprintf (file
, "\n");
4520 dump_generic_bb (file
, bb
, 2, flags
);
4522 fprintf (file
, "}\n");
4523 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4529 /* Make a tree based dump. */
4530 chain
= DECL_SAVED_TREE (fn
);
4532 if (TREE_CODE (chain
) == BIND_EXPR
)
4534 if (ignore_topmost_bind
)
4536 chain
= BIND_EXPR_BODY (chain
);
4544 if (!ignore_topmost_bind
)
4545 fprintf (file
, "{\n");
4550 fprintf (file
, "\n");
4552 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4553 if (ignore_topmost_bind
)
4554 fprintf (file
, "}\n");
4557 fprintf (file
, "\n\n");
4561 /* Pretty print of the loops intermediate representation. */
4562 static void print_loop (FILE *, struct loop
*, int);
4563 static void print_pred_bbs (FILE *, basic_block bb
);
4564 static void print_succ_bbs (FILE *, basic_block bb
);
4567 /* Print on FILE the indexes for the predecessors of basic_block BB. */
4570 print_pred_bbs (FILE *file
, basic_block bb
)
4575 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4576 fprintf (file
, "bb_%d ", e
->src
->index
);
4580 /* Print on FILE the indexes for the successors of basic_block BB. */
4583 print_succ_bbs (FILE *file
, basic_block bb
)
4588 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4589 fprintf (file
, "bb_%d ", e
->dest
->index
);
4593 /* Pretty print LOOP on FILE, indented INDENT spaces. */
4596 print_loop (FILE *file
, struct loop
*loop
, int indent
)
4604 s_indent
= (char *) alloca ((size_t) indent
+ 1);
4605 memset ((void *) s_indent
, ' ', (size_t) indent
);
4606 s_indent
[indent
] = '\0';
4608 /* Print the loop's header. */
4609 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
4611 /* Print the loop's body. */
4612 fprintf (file
, "%s{\n", s_indent
);
4614 if (bb
->loop_father
== loop
)
4616 /* Print the basic_block's header. */
4617 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
4618 print_pred_bbs (file
, bb
);
4619 fprintf (file
, "}, succs = {");
4620 print_succ_bbs (file
, bb
);
4621 fprintf (file
, "})\n");
4623 /* Print the basic_block's body. */
4624 fprintf (file
, "%s {\n", s_indent
);
4625 tree_dump_bb (bb
, file
, indent
+ 4);
4626 fprintf (file
, "%s }\n", s_indent
);
4629 print_loop (file
, loop
->inner
, indent
+ 2);
4630 fprintf (file
, "%s}\n", s_indent
);
4631 print_loop (file
, loop
->next
, indent
);
4635 /* Follow a CFG edge from the entry point of the program, and on entry
4636 of a loop, pretty print the loop structure on FILE. */
4639 print_loop_ir (FILE *file
)
4643 bb
= BASIC_BLOCK (0);
4644 if (bb
&& bb
->loop_father
)
4645 print_loop (file
, bb
->loop_father
, 0);
4649 /* Debugging loops structure at tree level. */
4652 debug_loop_ir (void)
4654 print_loop_ir (stderr
);
4658 /* Return true if BB ends with a call, possibly followed by some
4659 instructions that must stay with the call. Return false,
4663 tree_block_ends_with_call_p (basic_block bb
)
4665 block_stmt_iterator bsi
= bsi_last (bb
);
4666 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
4670 /* Return true if BB ends with a conditional branch. Return false,
4674 tree_block_ends_with_condjump_p (basic_block bb
)
4676 tree stmt
= last_stmt (bb
);
4677 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
4681 /* Return true if we need to add fake edge to exit at statement T.
4682 Helper function for tree_flow_call_edges_add. */
4685 need_fake_edge_p (tree t
)
4689 /* NORETURN and LONGJMP calls already have an edge to exit.
4690 CONST and PURE calls do not need one.
4691 We don't currently check for CONST and PURE here, although
4692 it would be a good idea, because those attributes are
4693 figured out from the RTL in mark_constant_function, and
4694 the counter incrementation code from -fprofile-arcs
4695 leads to different results from -fbranch-probabilities. */
4696 call
= get_call_expr_in (t
);
4698 && !(call_expr_flags (call
) & ECF_NORETURN
))
4701 if (TREE_CODE (t
) == ASM_EXPR
4702 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
4709 /* Add fake edges to the function exit for any non constant and non
4710 noreturn calls, volatile inline assembly in the bitmap of blocks
4711 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
4712 the number of blocks that were split.
4714 The goal is to expose cases in which entering a basic block does
4715 not imply that all subsequent instructions must be executed. */
4718 tree_flow_call_edges_add (sbitmap blocks
)
4721 int blocks_split
= 0;
4722 int last_bb
= last_basic_block
;
4723 bool check_last_block
= false;
4725 if (n_basic_blocks
== 0)
4729 check_last_block
= true;
4731 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
4733 /* In the last basic block, before epilogue generation, there will be
4734 a fallthru edge to EXIT. Special care is required if the last insn
4735 of the last basic block is a call because make_edge folds duplicate
4736 edges, which would result in the fallthru edge also being marked
4737 fake, which would result in the fallthru edge being removed by
4738 remove_fake_edges, which would result in an invalid CFG.
4740 Moreover, we can't elide the outgoing fake edge, since the block
4741 profiler needs to take this into account in order to solve the minimal
4742 spanning tree in the case that the call doesn't return.
4744 Handle this by adding a dummy instruction in a new last basic block. */
4745 if (check_last_block
)
4747 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
4748 block_stmt_iterator bsi
= bsi_last (bb
);
4750 if (!bsi_end_p (bsi
))
4753 if (need_fake_edge_p (t
))
4757 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4760 bsi_insert_on_edge (e
, build_empty_stmt ());
4761 bsi_commit_edge_inserts ();
4766 /* Now add fake edges to the function exit for any non constant
4767 calls since there is no way that we can determine if they will
4769 for (i
= 0; i
< last_bb
; i
++)
4771 basic_block bb
= BASIC_BLOCK (i
);
4772 block_stmt_iterator bsi
;
4773 tree stmt
, last_stmt
;
4778 if (blocks
&& !TEST_BIT (blocks
, i
))
4781 bsi
= bsi_last (bb
);
4782 if (!bsi_end_p (bsi
))
4784 last_stmt
= bsi_stmt (bsi
);
4787 stmt
= bsi_stmt (bsi
);
4788 if (need_fake_edge_p (stmt
))
4791 /* The handling above of the final block before the
4792 epilogue should be enough to verify that there is
4793 no edge to the exit block in CFG already.
4794 Calling make_edge in such case would cause us to
4795 mark that edge as fake and remove it later. */
4796 #ifdef ENABLE_CHECKING
4797 if (stmt
== last_stmt
)
4799 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4800 gcc_assert (e
== NULL
);
4804 /* Note that the following may create a new basic block
4805 and renumber the existing basic blocks. */
4806 if (stmt
!= last_stmt
)
4808 e
= split_block (bb
, stmt
);
4812 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
4816 while (!bsi_end_p (bsi
));
4821 verify_flow_info ();
4823 return blocks_split
;
4827 tree_purge_dead_eh_edges (basic_block bb
)
4829 bool changed
= false;
4832 tree stmt
= last_stmt (bb
);
4834 if (stmt
&& tree_can_throw_internal (stmt
))
4837 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
4839 if (e
->flags
& EDGE_EH
)
4848 /* Removal of dead EH edges might change dominators of not
4849 just immediate successors. E.g. when bb1 is changed so that
4850 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
4851 eh edges purged by this function in:
4863 idom(bb5) must be recomputed. For now just free the dominance
4866 free_dominance_info (CDI_DOMINATORS
);
4872 tree_purge_all_dead_eh_edges (bitmap blocks
)
4874 bool changed
= false;
4878 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
4880 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
4886 /* This function is called whenever a new edge is created or
4890 tree_execute_on_growing_pred (edge e
)
4892 basic_block bb
= e
->dest
;
4895 reserve_phi_args_for_new_edge (bb
);
4898 /* This function is called immediately before edge E is removed from
4899 the edge vector E->dest->preds. */
4902 tree_execute_on_shrinking_pred (edge e
)
4904 if (phi_nodes (e
->dest
))
4905 remove_phi_args (e
);
4908 /*---------------------------------------------------------------------------
4909 Helper functions for Loop versioning
4910 ---------------------------------------------------------------------------*/
4912 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
4913 of 'first'. Both of them are dominated by 'new_head' basic block. When
4914 'new_head' was created by 'second's incoming edge it received phi arguments
4915 on the edge by split_edge(). Later, additional edge 'e' was created to
4916 connect 'new_head' and 'first'. Now this routine adds phi args on this
4917 additional edge 'e' that new_head to second edge received as part of edge
4922 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
4923 basic_block new_head
, edge e
)
4926 edge e2
= find_edge (new_head
, second
);
4928 /* Because NEW_HEAD has been created by splitting SECOND's incoming
4929 edge, we should always have an edge from NEW_HEAD to SECOND. */
4930 gcc_assert (e2
!= NULL
);
4932 /* Browse all 'second' basic block phi nodes and add phi args to
4933 edge 'e' for 'first' head. PHI args are always in correct order. */
4935 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
4937 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
4939 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
4940 add_phi_arg (phi1
, def
, e
);
4944 /* Adds a if else statement to COND_BB with condition COND_EXPR.
4945 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
4946 the destination of the ELSE part. */
4948 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
4949 basic_block cond_bb
, void *cond_e
)
4951 block_stmt_iterator bsi
;
4952 tree goto1
= NULL_TREE
;
4953 tree goto2
= NULL_TREE
;
4954 tree new_cond_expr
= NULL_TREE
;
4955 tree cond_expr
= (tree
) cond_e
;
4958 /* Build new conditional expr */
4959 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
4960 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
4961 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
4963 /* Add new cond in cond_bb. */
4964 bsi
= bsi_start (cond_bb
);
4965 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
4966 /* Adjust edges appropriately to connect new head with first head
4967 as well as second head. */
4968 e0
= single_succ_edge (cond_bb
);
4969 e0
->flags
&= ~EDGE_FALLTHRU
;
4970 e0
->flags
|= EDGE_FALSE_VALUE
;
4973 struct cfg_hooks tree_cfg_hooks
= {
4975 tree_verify_flow_info
,
4976 tree_dump_bb
, /* dump_bb */
4977 create_bb
, /* create_basic_block */
4978 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
4979 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
4980 remove_bb
, /* delete_basic_block */
4981 tree_split_block
, /* split_block */
4982 tree_move_block_after
, /* move_block_after */
4983 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
4984 tree_merge_blocks
, /* merge_blocks */
4985 tree_predict_edge
, /* predict_edge */
4986 tree_predicted_by_p
, /* predicted_by_p */
4987 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
4988 tree_duplicate_bb
, /* duplicate_block */
4989 tree_split_edge
, /* split_edge */
4990 tree_make_forwarder_block
, /* make_forward_block */
4991 NULL
, /* tidy_fallthru_edge */
4992 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
4993 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
4994 tree_flow_call_edges_add
, /* flow_call_edges_add */
4995 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
4996 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
4997 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
4998 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
4999 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5000 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5001 flush_pending_stmts
/* flush_pending_stmts */
5005 /* Split all critical edges. */
5008 split_critical_edges (void)
5014 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5015 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5016 mappings around the calls to split_edge. */
5017 start_recording_case_labels ();
5020 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5021 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5026 end_recording_case_labels ();
5029 struct tree_opt_pass pass_split_crit_edges
=
5031 "crited", /* name */
5033 split_critical_edges
, /* execute */
5036 0, /* static_pass_number */
5037 TV_TREE_SPLIT_EDGES
, /* tv_id */
5038 PROP_cfg
, /* properties required */
5039 PROP_no_crit_edges
, /* properties_provided */
5040 0, /* properties_destroyed */
5041 0, /* todo_flags_start */
5042 TODO_dump_func
, /* todo_flags_finish */
5047 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5048 a temporary, make sure and register it to be renamed if necessary,
5049 and finally return the temporary. Put the statements to compute
5050 EXP before the current statement in BSI. */
5053 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5055 tree t
, new_stmt
, orig_stmt
;
5057 if (is_gimple_val (exp
))
5060 t
= make_rename_temp (type
, NULL
);
5061 new_stmt
= build (MODIFY_EXPR
, type
, t
, exp
);
5063 orig_stmt
= bsi_stmt (*bsi
);
5064 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5065 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5067 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5072 /* Build a ternary operation and gimplify it. Emit code before BSI.
5073 Return the gimple_val holding the result. */
5076 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5077 tree type
, tree a
, tree b
, tree c
)
5081 ret
= fold_build3 (code
, type
, a
, b
, c
);
5084 return gimplify_val (bsi
, type
, ret
);
5087 /* Build a binary operation and gimplify it. Emit code before BSI.
5088 Return the gimple_val holding the result. */
5091 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5092 tree type
, tree a
, tree b
)
5096 ret
= fold_build2 (code
, type
, a
, b
);
5099 return gimplify_val (bsi
, type
, ret
);
5102 /* Build a unary operation and gimplify it. Emit code before BSI.
5103 Return the gimple_val holding the result. */
5106 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5111 ret
= fold_build1 (code
, type
, a
);
5114 return gimplify_val (bsi
, type
, ret
);
5119 /* Emit return warnings. */
5122 execute_warn_function_return (void)
5124 #ifdef USE_MAPPED_LOCATION
5125 source_location location
;
5133 /* If we have a path to EXIT, then we do return. */
5134 if (TREE_THIS_VOLATILE (cfun
->decl
)
5135 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5137 #ifdef USE_MAPPED_LOCATION
5138 location
= UNKNOWN_LOCATION
;
5142 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5144 last
= last_stmt (e
->src
);
5145 if (TREE_CODE (last
) == RETURN_EXPR
5146 #ifdef USE_MAPPED_LOCATION
5147 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5149 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5153 #ifdef USE_MAPPED_LOCATION
5154 if (location
== UNKNOWN_LOCATION
)
5155 location
= cfun
->function_end_locus
;
5156 warning (0, "%H%<noreturn%> function does return", &location
);
5159 locus
= &cfun
->function_end_locus
;
5160 warning (0, "%H%<noreturn%> function does return", locus
);
5164 /* If we see "return;" in some basic block, then we do reach the end
5165 without returning a value. */
5166 else if (warn_return_type
5167 && !TREE_NO_WARNING (cfun
->decl
)
5168 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5169 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5171 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5173 tree last
= last_stmt (e
->src
);
5174 if (TREE_CODE (last
) == RETURN_EXPR
5175 && TREE_OPERAND (last
, 0) == NULL
5176 && !TREE_NO_WARNING (last
))
5178 #ifdef USE_MAPPED_LOCATION
5179 location
= EXPR_LOCATION (last
);
5180 if (location
== UNKNOWN_LOCATION
)
5181 location
= cfun
->function_end_locus
;
5182 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5184 locus
= EXPR_LOCUS (last
);
5186 locus
= &cfun
->function_end_locus
;
5187 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5189 TREE_NO_WARNING (cfun
->decl
) = 1;
5197 /* Given a basic block B which ends with a conditional and has
5198 precisely two successors, determine which of the edges is taken if
5199 the conditional is true and which is taken if the conditional is
5200 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5203 extract_true_false_edges_from_block (basic_block b
,
5207 edge e
= EDGE_SUCC (b
, 0);
5209 if (e
->flags
& EDGE_TRUE_VALUE
)
5212 *false_edge
= EDGE_SUCC (b
, 1);
5217 *true_edge
= EDGE_SUCC (b
, 1);
5221 struct tree_opt_pass pass_warn_function_return
=
5225 execute_warn_function_return
, /* execute */
5228 0, /* static_pass_number */
5230 PROP_cfg
, /* properties_required */
5231 0, /* properties_provided */
5232 0, /* properties_destroyed */
5233 0, /* todo_flags_start */
5234 0, /* todo_flags_finish */
5238 /* Emit noreturn warnings. */
5241 execute_warn_function_noreturn (void)
5243 if (warn_missing_noreturn
5244 && !TREE_THIS_VOLATILE (cfun
->decl
)
5245 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5246 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5247 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5248 "for attribute %<noreturn%>",
5252 struct tree_opt_pass pass_warn_function_noreturn
=
5256 execute_warn_function_noreturn
, /* execute */
5259 0, /* static_pass_number */
5261 PROP_cfg
, /* properties_required */
5262 0, /* properties_provided */
5263 0, /* properties_destroyed */
5264 0, /* todo_flags_start */
5265 0, /* todo_flags_finish */