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
;
132 n_basic_blocks
= NUM_FIXED_BLOCKS
;
133 last_basic_block
= NUM_FIXED_BLOCKS
;
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 BASIC_BLOCK (ENTRY_BLOCK
) = ENTRY_BLOCK_PTR
;
141 BASIC_BLOCK (EXIT_BLOCK
) = EXIT_BLOCK_PTR
;
142 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
143 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
146 /*---------------------------------------------------------------------------
148 ---------------------------------------------------------------------------*/
150 /* Entry point to the CFG builder for trees. TP points to the list of
151 statements to be added to the flowgraph. */
154 build_tree_cfg (tree
*tp
)
156 /* Register specific tree functions. */
157 tree_register_cfg_hooks ();
159 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
161 init_empty_tree_cfg ();
163 found_computed_goto
= 0;
166 /* Computed gotos are hell to deal with, especially if there are
167 lots of them with a large number of destinations. So we factor
168 them to a common computed goto location before we build the
169 edge list. After we convert back to normal form, we will un-factor
170 the computed gotos since factoring introduces an unwanted jump. */
171 if (found_computed_goto
)
172 factor_computed_gotos ();
174 /* Make sure there is always at least one block, even if it's empty. */
175 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
176 create_empty_bb (ENTRY_BLOCK_PTR
);
178 /* Adjust the size of the array. */
179 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
181 /* To speed up statement iterator walks, we first purge dead labels. */
182 cleanup_dead_labels ();
184 /* Group case nodes to reduce the number of edges.
185 We do this after cleaning up dead labels because otherwise we miss
186 a lot of obvious case merging opportunities. */
187 group_case_labels ();
189 /* Create the edges of the flowgraph. */
192 /* Debugging dumps. */
194 /* Write the flowgraph to a VCG file. */
196 int local_dump_flags
;
197 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
200 tree_cfg2vcg (dump_file
);
201 dump_end (TDI_vcg
, dump_file
);
205 #ifdef ENABLE_CHECKING
209 /* Dump a textual representation of the flowgraph. */
211 dump_tree_cfg (dump_file
, dump_flags
);
215 execute_build_cfg (void)
217 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
220 struct tree_opt_pass pass_build_cfg
=
224 execute_build_cfg
, /* execute */
227 0, /* static_pass_number */
228 TV_TREE_CFG
, /* tv_id */
229 PROP_gimple_leh
, /* properties_required */
230 PROP_cfg
, /* properties_provided */
231 0, /* properties_destroyed */
232 0, /* todo_flags_start */
233 TODO_verify_stmts
, /* todo_flags_finish */
237 /* Search the CFG for any computed gotos. If found, factor them to a
238 common computed goto site. Also record the location of that site so
239 that we can un-factor the gotos after we have converted back to
243 factor_computed_gotos (void)
246 tree factored_label_decl
= NULL
;
248 tree factored_computed_goto_label
= NULL
;
249 tree factored_computed_goto
= NULL
;
251 /* We know there are one or more computed gotos in this function.
252 Examine the last statement in each basic block to see if the block
253 ends with a computed goto. */
257 block_stmt_iterator bsi
= bsi_last (bb
);
262 last
= bsi_stmt (bsi
);
264 /* Ignore the computed goto we create when we factor the original
266 if (last
== factored_computed_goto
)
269 /* If the last statement is a computed goto, factor it. */
270 if (computed_goto_p (last
))
274 /* The first time we find a computed goto we need to create
275 the factored goto block and the variable each original
276 computed goto will use for their goto destination. */
277 if (! factored_computed_goto
)
279 basic_block new_bb
= create_empty_bb (bb
);
280 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
282 /* Create the destination of the factored goto. Each original
283 computed goto will put its desired destination into this
284 variable and jump to the label we create immediately
286 var
= create_tmp_var (ptr_type_node
, "gotovar");
288 /* Build a label for the new block which will contain the
289 factored computed goto. */
290 factored_label_decl
= create_artificial_label ();
291 factored_computed_goto_label
292 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
293 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
296 /* Build our new computed goto. */
297 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
298 bsi_insert_after (&new_bsi
, factored_computed_goto
,
302 /* Copy the original computed goto's destination into VAR. */
303 assignment
= build2 (MODIFY_EXPR
, ptr_type_node
,
304 var
, GOTO_DESTINATION (last
));
305 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
307 /* And re-vector the computed goto to the new destination. */
308 GOTO_DESTINATION (last
) = factored_label_decl
;
314 /* Build a flowgraph for the statement_list STMT_LIST. */
317 make_blocks (tree stmt_list
)
319 tree_stmt_iterator i
= tsi_start (stmt_list
);
321 bool start_new_block
= true;
322 bool first_stmt_of_list
= true;
323 basic_block bb
= ENTRY_BLOCK_PTR
;
325 while (!tsi_end_p (i
))
332 /* If the statement starts a new basic block or if we have determined
333 in a previous pass that we need to create a new block for STMT, do
335 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
337 if (!first_stmt_of_list
)
338 stmt_list
= tsi_split_statement_list_before (&i
);
339 bb
= create_basic_block (stmt_list
, NULL
, bb
);
340 start_new_block
= false;
343 /* Now add STMT to BB and create the subgraphs for special statement
345 set_bb_for_stmt (stmt
, bb
);
347 if (computed_goto_p (stmt
))
348 found_computed_goto
= true;
350 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
352 if (stmt_ends_bb_p (stmt
))
353 start_new_block
= true;
356 first_stmt_of_list
= false;
361 /* Create and return a new empty basic block after bb AFTER. */
364 create_bb (void *h
, void *e
, basic_block after
)
370 /* Create and initialize a new basic block. Since alloc_block uses
371 ggc_alloc_cleared to allocate a basic block, we do not have to
372 clear the newly allocated basic block here. */
375 bb
->index
= last_basic_block
;
377 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
379 /* Add the new block to the linked list of blocks. */
380 link_block (bb
, after
);
382 /* Grow the basic block array if needed. */
383 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
385 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
386 VARRAY_GROW (basic_block_info
, new_size
);
389 /* Add the newly created block to the array. */
390 BASIC_BLOCK (last_basic_block
) = bb
;
399 /*---------------------------------------------------------------------------
401 ---------------------------------------------------------------------------*/
403 /* Fold COND_EXPR_COND of each COND_EXPR. */
406 fold_cond_expr_cond (void)
412 tree stmt
= last_stmt (bb
);
415 && TREE_CODE (stmt
) == COND_EXPR
)
417 tree cond
= fold (COND_EXPR_COND (stmt
));
418 if (integer_zerop (cond
))
419 COND_EXPR_COND (stmt
) = boolean_false_node
;
420 else if (integer_onep (cond
))
421 COND_EXPR_COND (stmt
) = boolean_true_node
;
426 /* Join all the blocks in the flowgraph. */
433 /* Create an edge from entry to the first block with executable
435 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
437 /* Traverse the basic block array placing edges. */
440 tree first
= first_stmt (bb
);
441 tree last
= last_stmt (bb
);
445 /* Edges for statements that always alter flow control. */
446 if (is_ctrl_stmt (last
))
447 make_ctrl_stmt_edges (bb
);
449 /* Edges for statements that sometimes alter flow control. */
450 if (is_ctrl_altering_stmt (last
))
451 make_exit_edges (bb
);
454 /* Finally, if no edges were created above, this is a regular
455 basic block that only needs a fallthru edge. */
456 if (EDGE_COUNT (bb
->succs
) == 0)
457 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
460 /* We do not care about fake edges, so remove any that the CFG
461 builder inserted for completeness. */
462 remove_fake_exit_edges ();
464 /* Fold COND_EXPR_COND of each COND_EXPR. */
465 fold_cond_expr_cond ();
467 /* Clean up the graph and warn for unreachable code. */
472 /* Create edges for control statement at basic block BB. */
475 make_ctrl_stmt_edges (basic_block bb
)
477 tree last
= last_stmt (bb
);
480 switch (TREE_CODE (last
))
483 make_goto_expr_edges (bb
);
487 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
491 make_cond_expr_edges (bb
);
495 make_switch_expr_edges (bb
);
499 make_eh_edges (last
);
500 /* Yet another NORETURN hack. */
501 if (EDGE_COUNT (bb
->succs
) == 0)
502 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
511 /* Create exit edges for statements in block BB that alter the flow of
512 control. Statements that alter the control flow are 'goto', 'return'
513 and calls to non-returning functions. */
516 make_exit_edges (basic_block bb
)
518 tree last
= last_stmt (bb
), op
;
521 switch (TREE_CODE (last
))
526 /* If this function receives a nonlocal goto, then we need to
527 make edges from this call site to all the nonlocal goto
529 if (TREE_SIDE_EFFECTS (last
)
530 && current_function_has_nonlocal_label
)
531 make_goto_expr_edges (bb
);
533 /* If this statement has reachable exception handlers, then
534 create abnormal edges to them. */
535 make_eh_edges (last
);
537 /* Some calls are known not to return. For such calls we create
540 We really need to revamp how we build edges so that it's not
541 such a bloody pain to avoid creating edges for this case since
542 all we do is remove these edges when we're done building the
544 if (call_expr_flags (last
) & ECF_NORETURN
)
546 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
550 /* Don't forget the fall-thru edge. */
551 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
555 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
556 may have an abnormal edge. Search the RHS for this case and
557 create any required edges. */
558 op
= get_call_expr_in (last
);
559 if (op
&& TREE_SIDE_EFFECTS (op
)
560 && current_function_has_nonlocal_label
)
561 make_goto_expr_edges (bb
);
563 make_eh_edges (last
);
564 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
573 /* Create the edges for a COND_EXPR starting at block BB.
574 At this point, both clauses must contain only simple gotos. */
577 make_cond_expr_edges (basic_block bb
)
579 tree entry
= last_stmt (bb
);
580 basic_block then_bb
, else_bb
;
581 tree then_label
, else_label
;
585 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
587 /* Entry basic blocks for each component. */
588 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
589 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
590 then_bb
= label_to_block (then_label
);
591 else_bb
= label_to_block (else_label
);
593 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
594 #ifdef USE_MAPPED_LOCATION
595 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
597 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
599 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
602 #ifdef USE_MAPPED_LOCATION
603 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
605 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
610 /* Hashing routine for EDGE_TO_CASES. */
613 edge_to_cases_hash (const void *p
)
615 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
617 /* Hash on the edge itself (which is a pointer). */
618 return htab_hash_pointer (e
);
621 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
622 for equality is just a pointer comparison. */
625 edge_to_cases_eq (const void *p1
, const void *p2
)
627 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
628 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
633 /* Called for each element in the hash table (P) as we delete the
634 edge to cases hash table.
636 Clear all the TREE_CHAINs to prevent problems with copying of
637 SWITCH_EXPRs and structure sharing rules, then free the hash table
641 edge_to_cases_cleanup (void *p
)
643 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
646 for (t
= elt
->case_labels
; t
; t
= next
)
648 next
= TREE_CHAIN (t
);
649 TREE_CHAIN (t
) = NULL
;
654 /* Start recording information mapping edges to case labels. */
657 start_recording_case_labels (void)
659 gcc_assert (edge_to_cases
== NULL
);
661 edge_to_cases
= htab_create (37,
664 edge_to_cases_cleanup
);
667 /* Return nonzero if we are recording information for case labels. */
670 recording_case_labels_p (void)
672 return (edge_to_cases
!= NULL
);
675 /* Stop recording information mapping edges to case labels and
676 remove any information we have recorded. */
678 end_recording_case_labels (void)
680 htab_delete (edge_to_cases
);
681 edge_to_cases
= NULL
;
684 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
687 record_switch_edge (edge e
, tree case_label
)
689 struct edge_to_cases_elt
*elt
;
692 /* Build a hash table element so we can see if E is already
694 elt
= XNEW (struct edge_to_cases_elt
);
696 elt
->case_labels
= case_label
;
698 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
702 /* E was not in the hash table. Install E into the hash table. */
707 /* E was already in the hash table. Free ELT as we do not need it
711 /* Get the entry stored in the hash table. */
712 elt
= (struct edge_to_cases_elt
*) *slot
;
714 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
715 TREE_CHAIN (case_label
) = elt
->case_labels
;
716 elt
->case_labels
= case_label
;
720 /* If we are inside a {start,end}_recording_cases block, then return
721 a chain of CASE_LABEL_EXPRs from T which reference E.
723 Otherwise return NULL. */
726 get_cases_for_edge (edge e
, tree t
)
728 struct edge_to_cases_elt elt
, *elt_p
;
733 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
734 chains available. Return NULL so the caller can detect this case. */
735 if (!recording_case_labels_p ())
740 elt
.case_labels
= NULL
;
741 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
745 elt_p
= (struct edge_to_cases_elt
*)*slot
;
746 return elt_p
->case_labels
;
749 /* If we did not find E in the hash table, then this must be the first
750 time we have been queried for information about E & T. Add all the
751 elements from T to the hash table then perform the query again. */
753 vec
= SWITCH_LABELS (t
);
754 n
= TREE_VEC_LENGTH (vec
);
755 for (i
= 0; i
< n
; i
++)
757 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
758 basic_block label_bb
= label_to_block (lab
);
759 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
764 /* Create the edges for a SWITCH_EXPR starting at block BB.
765 At this point, the switch body has been lowered and the
766 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
769 make_switch_expr_edges (basic_block bb
)
771 tree entry
= last_stmt (bb
);
775 vec
= SWITCH_LABELS (entry
);
776 n
= TREE_VEC_LENGTH (vec
);
778 for (i
= 0; i
< n
; ++i
)
780 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
781 basic_block label_bb
= label_to_block (lab
);
782 make_edge (bb
, label_bb
, 0);
787 /* Return the basic block holding label DEST. */
790 label_to_block_fn (struct function
*ifun
, tree dest
)
792 int uid
= LABEL_DECL_UID (dest
);
794 /* We would die hard when faced by an undefined label. Emit a label to
795 the very first basic block. This will hopefully make even the dataflow
796 and undefined variable warnings quite right. */
797 if ((errorcount
|| sorrycount
) && uid
< 0)
799 block_stmt_iterator bsi
=
800 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
803 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
804 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
805 uid
= LABEL_DECL_UID (dest
);
807 if (VARRAY_SIZE (ifun
->cfg
->x_label_to_block_map
) <= (unsigned int)uid
)
809 return VARRAY_BB (ifun
->cfg
->x_label_to_block_map
, uid
);
812 /* Create edges for a goto statement at block BB. */
815 make_goto_expr_edges (basic_block bb
)
818 basic_block target_bb
;
820 block_stmt_iterator last
= bsi_last (bb
);
822 goto_t
= bsi_stmt (last
);
824 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
825 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
826 from a nonlocal goto. */
827 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
831 tree dest
= GOTO_DESTINATION (goto_t
);
834 /* A GOTO to a local label creates normal edges. */
835 if (simple_goto_p (goto_t
))
837 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
838 #ifdef USE_MAPPED_LOCATION
839 e
->goto_locus
= EXPR_LOCATION (goto_t
);
841 e
->goto_locus
= EXPR_LOCUS (goto_t
);
847 /* Nothing more to do for nonlocal gotos. */
848 if (TREE_CODE (dest
) == LABEL_DECL
)
851 /* Computed gotos remain. */
854 /* Look for the block starting with the destination label. In the
855 case of a computed goto, make an edge to any label block we find
857 FOR_EACH_BB (target_bb
)
859 block_stmt_iterator bsi
;
861 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
863 tree target
= bsi_stmt (bsi
);
865 if (TREE_CODE (target
) != LABEL_EXPR
)
869 /* Computed GOTOs. Make an edge to every label block that has
870 been marked as a potential target for a computed goto. */
871 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
872 /* Nonlocal GOTO target. Make an edge to every label block
873 that has been marked as a potential target for a nonlocal
875 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
877 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
883 /* Degenerate case of computed goto with no labels. */
884 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
885 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
889 /*---------------------------------------------------------------------------
891 ---------------------------------------------------------------------------*/
893 /* Cleanup useless labels in basic blocks. This is something we wish
894 to do early because it allows us to group case labels before creating
895 the edges for the CFG, and it speeds up block statement iterators in
897 We only run this pass once, running it more than once is probably not
900 /* A map from basic block index to the leading label of that block. */
901 static tree
*label_for_bb
;
903 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
905 update_eh_label (struct eh_region
*region
)
907 tree old_label
= get_eh_region_tree_label (region
);
911 basic_block bb
= label_to_block (old_label
);
913 /* ??? After optimizing, there may be EH regions with labels
914 that have already been removed from the function body, so
915 there is no basic block for them. */
919 new_label
= label_for_bb
[bb
->index
];
920 set_eh_region_tree_label (region
, new_label
);
924 /* Given LABEL return the first label in the same basic block. */
926 main_block_label (tree label
)
928 basic_block bb
= label_to_block (label
);
930 /* label_to_block possibly inserted undefined label into the chain. */
931 if (!label_for_bb
[bb
->index
])
932 label_for_bb
[bb
->index
] = label
;
933 return label_for_bb
[bb
->index
];
936 /* Cleanup redundant labels. This is a three-step process:
937 1) Find the leading label for each block.
938 2) Redirect all references to labels to the leading labels.
939 3) Cleanup all useless labels. */
942 cleanup_dead_labels (void)
945 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
947 /* Find a suitable label for each block. We use the first user-defined
948 label if there is one, or otherwise just the first label we see. */
951 block_stmt_iterator i
;
953 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
955 tree label
, stmt
= bsi_stmt (i
);
957 if (TREE_CODE (stmt
) != LABEL_EXPR
)
960 label
= LABEL_EXPR_LABEL (stmt
);
962 /* If we have not yet seen a label for the current block,
963 remember this one and see if there are more labels. */
964 if (! label_for_bb
[bb
->index
])
966 label_for_bb
[bb
->index
] = label
;
970 /* If we did see a label for the current block already, but it
971 is an artificially created label, replace it if the current
972 label is a user defined label. */
973 if (! DECL_ARTIFICIAL (label
)
974 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
976 label_for_bb
[bb
->index
] = label
;
982 /* Now redirect all jumps/branches to the selected label.
983 First do so for each block ending in a control statement. */
986 tree stmt
= last_stmt (bb
);
990 switch (TREE_CODE (stmt
))
994 tree true_branch
, false_branch
;
996 true_branch
= COND_EXPR_THEN (stmt
);
997 false_branch
= COND_EXPR_ELSE (stmt
);
999 GOTO_DESTINATION (true_branch
)
1000 = main_block_label (GOTO_DESTINATION (true_branch
));
1001 GOTO_DESTINATION (false_branch
)
1002 = main_block_label (GOTO_DESTINATION (false_branch
));
1010 tree vec
= SWITCH_LABELS (stmt
);
1011 size_t n
= TREE_VEC_LENGTH (vec
);
1013 /* Replace all destination labels. */
1014 for (i
= 0; i
< n
; ++i
)
1016 tree elt
= TREE_VEC_ELT (vec
, i
);
1017 tree label
= main_block_label (CASE_LABEL (elt
));
1018 CASE_LABEL (elt
) = label
;
1023 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1024 remove them until after we've created the CFG edges. */
1026 if (! computed_goto_p (stmt
))
1028 GOTO_DESTINATION (stmt
)
1029 = main_block_label (GOTO_DESTINATION (stmt
));
1038 for_each_eh_region (update_eh_label
);
1040 /* Finally, purge dead labels. All user-defined labels and labels that
1041 can be the target of non-local gotos are preserved. */
1044 block_stmt_iterator i
;
1045 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1047 if (! label_for_this_bb
)
1050 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1052 tree label
, stmt
= bsi_stmt (i
);
1054 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1057 label
= LABEL_EXPR_LABEL (stmt
);
1059 if (label
== label_for_this_bb
1060 || ! DECL_ARTIFICIAL (label
)
1061 || DECL_NONLOCAL (label
))
1068 free (label_for_bb
);
1071 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1072 and scan the sorted vector of cases. Combine the ones jumping to the
1074 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1077 group_case_labels (void)
1083 tree stmt
= last_stmt (bb
);
1084 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1086 tree labels
= SWITCH_LABELS (stmt
);
1087 int old_size
= TREE_VEC_LENGTH (labels
);
1088 int i
, j
, new_size
= old_size
;
1089 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1092 /* The default label is always the last case in a switch
1093 statement after gimplification. */
1094 default_label
= CASE_LABEL (default_case
);
1096 /* Look for possible opportunities to merge cases.
1097 Ignore the last element of the label vector because it
1098 must be the default case. */
1100 while (i
< old_size
- 1)
1102 tree base_case
, base_label
, base_high
;
1103 base_case
= TREE_VEC_ELT (labels
, i
);
1105 gcc_assert (base_case
);
1106 base_label
= CASE_LABEL (base_case
);
1108 /* Discard cases that have the same destination as the
1110 if (base_label
== default_label
)
1112 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1118 base_high
= CASE_HIGH (base_case
) ?
1119 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1121 /* Try to merge case labels. Break out when we reach the end
1122 of the label vector or when we cannot merge the next case
1123 label with the current one. */
1124 while (i
< old_size
- 1)
1126 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1127 tree merge_label
= CASE_LABEL (merge_case
);
1128 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1129 integer_one_node
, 1);
1131 /* Merge the cases if they jump to the same place,
1132 and their ranges are consecutive. */
1133 if (merge_label
== base_label
1134 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1136 base_high
= CASE_HIGH (merge_case
) ?
1137 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1138 CASE_HIGH (base_case
) = base_high
;
1139 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1148 /* Compress the case labels in the label vector, and adjust the
1149 length of the vector. */
1150 for (i
= 0, j
= 0; i
< new_size
; i
++)
1152 while (! TREE_VEC_ELT (labels
, j
))
1154 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1156 TREE_VEC_LENGTH (labels
) = new_size
;
1161 /* Checks whether we can merge block B into block A. */
1164 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1167 block_stmt_iterator bsi
;
1170 if (!single_succ_p (a
))
1173 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1176 if (single_succ (a
) != b
)
1179 if (!single_pred_p (b
))
1182 if (b
== EXIT_BLOCK_PTR
)
1185 /* If A ends by a statement causing exceptions or something similar, we
1186 cannot merge the blocks. */
1187 stmt
= last_stmt (a
);
1188 if (stmt
&& stmt_ends_bb_p (stmt
))
1191 /* Do not allow a block with only a non-local label to be merged. */
1192 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1193 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1196 /* It must be possible to eliminate all phi nodes in B. If ssa form
1197 is not up-to-date, we cannot eliminate any phis. */
1198 phi
= phi_nodes (b
);
1201 if (need_ssa_update_p ())
1204 for (; phi
; phi
= PHI_CHAIN (phi
))
1205 if (!is_gimple_reg (PHI_RESULT (phi
))
1206 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1210 /* Do not remove user labels. */
1211 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1213 stmt
= bsi_stmt (bsi
);
1214 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1216 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1220 /* Protect the loop latches. */
1222 && b
->loop_father
->latch
== b
)
1228 /* Replaces all uses of NAME by VAL. */
1231 replace_uses_by (tree name
, tree val
)
1233 imm_use_iterator imm_iter
;
1238 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1240 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1242 stmt
= USE_STMT (use
);
1243 replace_exp (use
, val
);
1245 if (TREE_CODE (stmt
) == PHI_NODE
)
1247 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1248 if (e
->flags
& EDGE_ABNORMAL
)
1250 /* This can only occur for virtual operands, since
1251 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1252 would prevent replacement. */
1253 gcc_assert (!is_gimple_reg (name
));
1254 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1258 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1261 /* We do not update the statements in the loop above. Consider
1264 If we performed the update in the first loop, the statement
1265 would be rescanned after first occurrence of w is replaced,
1266 the new uses would be placed to the beginning of the list,
1267 and we would never process them. */
1268 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1272 fold_stmt_inplace (stmt
);
1274 rhs
= get_rhs (stmt
);
1275 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1276 recompute_tree_invariant_for_addr_expr (rhs
);
1278 /* If the statement could throw and now cannot, we need to prune cfg. */
1279 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
1280 tree_purge_dead_eh_edges (bb_for_stmt (stmt
));
1282 mark_new_vars_to_rename (stmt
);
1285 VEC_free (tree
, heap
, stmts
);
1287 /* Also update the trees stored in loop structures. */
1292 for (i
= 0; i
< current_loops
->num
; i
++)
1294 loop
= current_loops
->parray
[i
];
1296 substitute_in_loop_info (loop
, name
, val
);
1301 /* Merge block B into block A. */
1304 tree_merge_blocks (basic_block a
, basic_block b
)
1306 block_stmt_iterator bsi
;
1307 tree_stmt_iterator last
;
1311 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1313 /* Remove all single-valued PHI nodes from block B of the form
1314 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1316 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1318 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1320 bool may_replace_uses
= may_propagate_copy (def
, use
);
1322 /* In case we have loops to care about, do not propagate arguments of
1323 loop closed ssa phi nodes. */
1325 && is_gimple_reg (def
)
1326 && TREE_CODE (use
) == SSA_NAME
1327 && a
->loop_father
!= b
->loop_father
)
1328 may_replace_uses
= false;
1330 if (!may_replace_uses
)
1332 gcc_assert (is_gimple_reg (def
));
1334 /* Note that just emitting the copies is fine -- there is no problem
1335 with ordering of phi nodes. This is because A is the single
1336 predecessor of B, therefore results of the phi nodes cannot
1337 appear as arguments of the phi nodes. */
1338 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1339 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1340 SET_PHI_RESULT (phi
, NULL_TREE
);
1341 SSA_NAME_DEF_STMT (def
) = copy
;
1344 replace_uses_by (def
, use
);
1346 remove_phi_node (phi
, NULL
);
1349 /* Ensure that B follows A. */
1350 move_block_after (b
, a
);
1352 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1353 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1355 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1356 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1358 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1360 tree label
= bsi_stmt (bsi
);
1363 /* Now that we can thread computed gotos, we might have
1364 a situation where we have a forced label in block B
1365 However, the label at the start of block B might still be
1366 used in other ways (think about the runtime checking for
1367 Fortran assigned gotos). So we can not just delete the
1368 label. Instead we move the label to the start of block A. */
1369 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1371 block_stmt_iterator dest_bsi
= bsi_start (a
);
1372 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1377 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1382 /* Merge the chains. */
1383 last
= tsi_last (a
->stmt_list
);
1384 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1385 b
->stmt_list
= NULL
;
1389 /* Walk the function tree removing unnecessary statements.
1391 * Empty statement nodes are removed
1393 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1395 * Unnecessary COND_EXPRs are removed
1397 * Some unnecessary BIND_EXPRs are removed
1399 Clearly more work could be done. The trick is doing the analysis
1400 and removal fast enough to be a net improvement in compile times.
1402 Note that when we remove a control structure such as a COND_EXPR
1403 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1404 to ensure we eliminate all the useless code. */
1415 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1418 remove_useless_stmts_warn_notreached (tree stmt
)
1420 if (EXPR_HAS_LOCATION (stmt
))
1422 location_t loc
= EXPR_LOCATION (stmt
);
1423 if (LOCATION_LINE (loc
) > 0)
1425 warning (0, "%Hwill never be executed", &loc
);
1430 switch (TREE_CODE (stmt
))
1432 case STATEMENT_LIST
:
1434 tree_stmt_iterator i
;
1435 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1436 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1442 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1444 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1446 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1450 case TRY_FINALLY_EXPR
:
1451 case TRY_CATCH_EXPR
:
1452 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1454 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1459 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1460 case EH_FILTER_EXPR
:
1461 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1463 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1466 /* Not a live container. */
1474 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1476 tree then_clause
, else_clause
, cond
;
1477 bool save_has_label
, then_has_label
, else_has_label
;
1479 save_has_label
= data
->has_label
;
1480 data
->has_label
= false;
1481 data
->last_goto
= NULL
;
1483 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1485 then_has_label
= data
->has_label
;
1486 data
->has_label
= false;
1487 data
->last_goto
= NULL
;
1489 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1491 else_has_label
= data
->has_label
;
1492 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1494 then_clause
= COND_EXPR_THEN (*stmt_p
);
1495 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1496 cond
= fold (COND_EXPR_COND (*stmt_p
));
1498 /* If neither arm does anything at all, we can remove the whole IF. */
1499 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1501 *stmt_p
= build_empty_stmt ();
1502 data
->repeat
= true;
1505 /* If there are no reachable statements in an arm, then we can
1506 zap the entire conditional. */
1507 else if (integer_nonzerop (cond
) && !else_has_label
)
1509 if (warn_notreached
)
1510 remove_useless_stmts_warn_notreached (else_clause
);
1511 *stmt_p
= then_clause
;
1512 data
->repeat
= true;
1514 else if (integer_zerop (cond
) && !then_has_label
)
1516 if (warn_notreached
)
1517 remove_useless_stmts_warn_notreached (then_clause
);
1518 *stmt_p
= else_clause
;
1519 data
->repeat
= true;
1522 /* Check a couple of simple things on then/else with single stmts. */
1525 tree then_stmt
= expr_only (then_clause
);
1526 tree else_stmt
= expr_only (else_clause
);
1528 /* Notice branches to a common destination. */
1529 if (then_stmt
&& else_stmt
1530 && TREE_CODE (then_stmt
) == GOTO_EXPR
1531 && TREE_CODE (else_stmt
) == GOTO_EXPR
1532 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1534 *stmt_p
= then_stmt
;
1535 data
->repeat
= true;
1538 /* If the THEN/ELSE clause merely assigns a value to a variable or
1539 parameter which is already known to contain that value, then
1540 remove the useless THEN/ELSE clause. */
1541 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1544 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1545 && TREE_OPERAND (else_stmt
, 0) == cond
1546 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1547 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1549 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1550 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1551 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1552 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1554 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1555 ? then_stmt
: else_stmt
);
1556 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1557 ? &COND_EXPR_THEN (*stmt_p
)
1558 : &COND_EXPR_ELSE (*stmt_p
));
1561 && TREE_CODE (stmt
) == MODIFY_EXPR
1562 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1563 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1564 *location
= alloc_stmt_list ();
1568 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1569 would be re-introduced during lowering. */
1570 data
->last_goto
= NULL
;
1575 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1577 bool save_may_branch
, save_may_throw
;
1578 bool this_may_branch
, this_may_throw
;
1580 /* Collect may_branch and may_throw information for the body only. */
1581 save_may_branch
= data
->may_branch
;
1582 save_may_throw
= data
->may_throw
;
1583 data
->may_branch
= false;
1584 data
->may_throw
= false;
1585 data
->last_goto
= NULL
;
1587 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1589 this_may_branch
= data
->may_branch
;
1590 this_may_throw
= data
->may_throw
;
1591 data
->may_branch
|= save_may_branch
;
1592 data
->may_throw
|= save_may_throw
;
1593 data
->last_goto
= NULL
;
1595 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1597 /* If the body is empty, then we can emit the FINALLY block without
1598 the enclosing TRY_FINALLY_EXPR. */
1599 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1601 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1602 data
->repeat
= true;
1605 /* If the handler is empty, then we can emit the TRY block without
1606 the enclosing TRY_FINALLY_EXPR. */
1607 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1609 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1610 data
->repeat
= true;
1613 /* If the body neither throws, nor branches, then we can safely
1614 string the TRY and FINALLY blocks together. */
1615 else if (!this_may_branch
&& !this_may_throw
)
1617 tree stmt
= *stmt_p
;
1618 *stmt_p
= TREE_OPERAND (stmt
, 0);
1619 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1620 data
->repeat
= true;
1626 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1628 bool save_may_throw
, this_may_throw
;
1629 tree_stmt_iterator i
;
1632 /* Collect may_throw information for the body only. */
1633 save_may_throw
= data
->may_throw
;
1634 data
->may_throw
= false;
1635 data
->last_goto
= NULL
;
1637 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1639 this_may_throw
= data
->may_throw
;
1640 data
->may_throw
= save_may_throw
;
1642 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1643 if (!this_may_throw
)
1645 if (warn_notreached
)
1646 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1647 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1648 data
->repeat
= true;
1652 /* Process the catch clause specially. We may be able to tell that
1653 no exceptions propagate past this point. */
1655 this_may_throw
= true;
1656 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1657 stmt
= tsi_stmt (i
);
1658 data
->last_goto
= NULL
;
1660 switch (TREE_CODE (stmt
))
1663 for (; !tsi_end_p (i
); tsi_next (&i
))
1665 stmt
= tsi_stmt (i
);
1666 /* If we catch all exceptions, then the body does not
1667 propagate exceptions past this point. */
1668 if (CATCH_TYPES (stmt
) == NULL
)
1669 this_may_throw
= false;
1670 data
->last_goto
= NULL
;
1671 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1675 case EH_FILTER_EXPR
:
1676 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1677 this_may_throw
= false;
1678 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1679 this_may_throw
= false;
1680 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1684 /* Otherwise this is a cleanup. */
1685 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1687 /* If the cleanup is empty, then we can emit the TRY block without
1688 the enclosing TRY_CATCH_EXPR. */
1689 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1691 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1692 data
->repeat
= true;
1696 data
->may_throw
|= this_may_throw
;
1701 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1705 /* First remove anything underneath the BIND_EXPR. */
1706 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1708 /* If the BIND_EXPR has no variables, then we can pull everything
1709 up one level and remove the BIND_EXPR, unless this is the toplevel
1710 BIND_EXPR for the current function or an inlined function.
1712 When this situation occurs we will want to apply this
1713 optimization again. */
1714 block
= BIND_EXPR_BLOCK (*stmt_p
);
1715 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1716 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1718 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1719 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1722 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1723 data
->repeat
= true;
1729 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1731 tree dest
= GOTO_DESTINATION (*stmt_p
);
1733 data
->may_branch
= true;
1734 data
->last_goto
= NULL
;
1736 /* Record the last goto expr, so that we can delete it if unnecessary. */
1737 if (TREE_CODE (dest
) == LABEL_DECL
)
1738 data
->last_goto
= stmt_p
;
1743 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1745 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1747 data
->has_label
= true;
1749 /* We do want to jump across non-local label receiver code. */
1750 if (DECL_NONLOCAL (label
))
1751 data
->last_goto
= NULL
;
1753 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1755 *data
->last_goto
= build_empty_stmt ();
1756 data
->repeat
= true;
1759 /* ??? Add something here to delete unused labels. */
1763 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1764 decl. This allows us to eliminate redundant or useless
1765 calls to "const" functions.
1767 Gimplifier already does the same operation, but we may notice functions
1768 being const and pure once their calls has been gimplified, so we need
1769 to update the flag. */
1772 update_call_expr_flags (tree call
)
1774 tree decl
= get_callee_fndecl (call
);
1777 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1778 TREE_SIDE_EFFECTS (call
) = 0;
1779 if (TREE_NOTHROW (decl
))
1780 TREE_NOTHROW (call
) = 1;
1784 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1787 notice_special_calls (tree t
)
1789 int flags
= call_expr_flags (t
);
1791 if (flags
& ECF_MAY_BE_ALLOCA
)
1792 current_function_calls_alloca
= true;
1793 if (flags
& ECF_RETURNS_TWICE
)
1794 current_function_calls_setjmp
= true;
1798 /* Clear flags set by notice_special_calls. Used by dead code removal
1799 to update the flags. */
1802 clear_special_calls (void)
1804 current_function_calls_alloca
= false;
1805 current_function_calls_setjmp
= false;
1810 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1814 switch (TREE_CODE (t
))
1817 remove_useless_stmts_cond (tp
, data
);
1820 case TRY_FINALLY_EXPR
:
1821 remove_useless_stmts_tf (tp
, data
);
1824 case TRY_CATCH_EXPR
:
1825 remove_useless_stmts_tc (tp
, data
);
1829 remove_useless_stmts_bind (tp
, data
);
1833 remove_useless_stmts_goto (tp
, data
);
1837 remove_useless_stmts_label (tp
, data
);
1842 data
->last_goto
= NULL
;
1843 data
->may_branch
= true;
1848 data
->last_goto
= NULL
;
1849 notice_special_calls (t
);
1850 update_call_expr_flags (t
);
1851 if (tree_could_throw_p (t
))
1852 data
->may_throw
= true;
1856 data
->last_goto
= NULL
;
1858 op
= get_call_expr_in (t
);
1861 update_call_expr_flags (op
);
1862 notice_special_calls (op
);
1864 if (tree_could_throw_p (t
))
1865 data
->may_throw
= true;
1868 case STATEMENT_LIST
:
1870 tree_stmt_iterator i
= tsi_start (t
);
1871 while (!tsi_end_p (i
))
1874 if (IS_EMPTY_STMT (t
))
1880 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1883 if (TREE_CODE (t
) == STATEMENT_LIST
)
1885 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1895 data
->last_goto
= NULL
;
1899 data
->last_goto
= NULL
;
1905 remove_useless_stmts (void)
1907 struct rus_data data
;
1909 clear_special_calls ();
1913 memset (&data
, 0, sizeof (data
));
1914 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1916 while (data
.repeat
);
1920 struct tree_opt_pass pass_remove_useless_stmts
=
1922 "useless", /* name */
1924 remove_useless_stmts
, /* execute */
1927 0, /* static_pass_number */
1929 PROP_gimple_any
, /* properties_required */
1930 0, /* properties_provided */
1931 0, /* properties_destroyed */
1932 0, /* todo_flags_start */
1933 TODO_dump_func
, /* todo_flags_finish */
1937 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1940 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1944 /* Since this block is no longer reachable, we can just delete all
1945 of its PHI nodes. */
1946 phi
= phi_nodes (bb
);
1949 tree next
= PHI_CHAIN (phi
);
1950 remove_phi_node (phi
, NULL_TREE
);
1954 /* Remove edges to BB's successors. */
1955 while (EDGE_COUNT (bb
->succs
) > 0)
1956 remove_edge (EDGE_SUCC (bb
, 0));
1960 /* Remove statements of basic block BB. */
1963 remove_bb (basic_block bb
)
1965 block_stmt_iterator i
;
1966 #ifdef USE_MAPPED_LOCATION
1967 source_location loc
= UNKNOWN_LOCATION
;
1969 source_locus loc
= 0;
1974 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1975 if (dump_flags
& TDF_DETAILS
)
1977 dump_bb (bb
, dump_file
, 0);
1978 fprintf (dump_file
, "\n");
1982 /* If we remove the header or the latch of a loop, mark the loop for
1983 removal by setting its header and latch to NULL. */
1986 struct loop
*loop
= bb
->loop_father
;
1988 if (loop
->latch
== bb
1989 || loop
->header
== bb
)
1992 loop
->header
= NULL
;
1994 /* Also clean up the information associated with the loop. Updating
1995 it would waste time. More importantly, it may refer to ssa
1996 names that were defined in other removed basic block -- these
1997 ssa names are now removed and invalid. */
1998 free_numbers_of_iterations_estimates_loop (loop
);
2002 /* Remove all the instructions in the block. */
2003 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2005 tree stmt
= bsi_stmt (i
);
2006 if (TREE_CODE (stmt
) == LABEL_EXPR
2007 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2008 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2011 block_stmt_iterator new_bsi
;
2013 /* A non-reachable non-local label may still be referenced.
2014 But it no longer needs to carry the extra semantics of
2016 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2018 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2019 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2022 new_bb
= bb
->prev_bb
;
2023 new_bsi
= bsi_start (new_bb
);
2025 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2029 /* Release SSA definitions if we are in SSA. Note that we
2030 may be called when not in SSA. For example,
2031 final_cleanup calls this function via
2032 cleanup_tree_cfg. */
2034 release_defs (stmt
);
2039 /* Don't warn for removed gotos. Gotos are often removed due to
2040 jump threading, thus resulting in bogus warnings. Not great,
2041 since this way we lose warnings for gotos in the original
2042 program that are indeed unreachable. */
2043 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2045 #ifdef USE_MAPPED_LOCATION
2046 if (EXPR_HAS_LOCATION (stmt
))
2047 loc
= EXPR_LOCATION (stmt
);
2050 t
= EXPR_LOCUS (stmt
);
2051 if (t
&& LOCATION_LINE (*t
) > 0)
2057 /* If requested, give a warning that the first statement in the
2058 block is unreachable. We walk statements backwards in the
2059 loop above, so the last statement we process is the first statement
2061 #ifdef USE_MAPPED_LOCATION
2062 if (loc
> BUILTINS_LOCATION
)
2063 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2066 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2069 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2073 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2074 predicate VAL, return the edge that will be taken out of the block.
2075 If VAL does not match a unique edge, NULL is returned. */
2078 find_taken_edge (basic_block bb
, tree val
)
2082 stmt
= last_stmt (bb
);
2085 gcc_assert (is_ctrl_stmt (stmt
));
2088 if (! is_gimple_min_invariant (val
))
2091 if (TREE_CODE (stmt
) == COND_EXPR
)
2092 return find_taken_edge_cond_expr (bb
, val
);
2094 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2095 return find_taken_edge_switch_expr (bb
, val
);
2097 if (computed_goto_p (stmt
))
2098 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2103 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2104 statement, determine which of the outgoing edges will be taken out of the
2105 block. Return NULL if either edge may be taken. */
2108 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2113 dest
= label_to_block (val
);
2116 e
= find_edge (bb
, dest
);
2117 gcc_assert (e
!= NULL
);
2123 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2124 statement, determine which of the two edges will be taken out of the
2125 block. Return NULL if either edge may be taken. */
2128 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2130 edge true_edge
, false_edge
;
2132 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2134 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2135 return (zero_p (val
) ? false_edge
: true_edge
);
2138 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2139 statement, determine which edge will be taken out of the block. Return
2140 NULL if any edge may be taken. */
2143 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2145 tree switch_expr
, taken_case
;
2146 basic_block dest_bb
;
2149 switch_expr
= last_stmt (bb
);
2150 taken_case
= find_case_label_for_value (switch_expr
, val
);
2151 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2153 e
= find_edge (bb
, dest_bb
);
2159 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2160 We can make optimal use here of the fact that the case labels are
2161 sorted: We can do a binary search for a case matching VAL. */
2164 find_case_label_for_value (tree switch_expr
, tree val
)
2166 tree vec
= SWITCH_LABELS (switch_expr
);
2167 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2168 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2170 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2172 size_t i
= (high
+ low
) / 2;
2173 tree t
= TREE_VEC_ELT (vec
, i
);
2176 /* Cache the result of comparing CASE_LOW and val. */
2177 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2184 if (CASE_HIGH (t
) == NULL
)
2186 /* A singe-valued case label. */
2192 /* A case range. We can only handle integer ranges. */
2193 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2198 return default_case
;
2204 /*---------------------------------------------------------------------------
2206 ---------------------------------------------------------------------------*/
2208 /* Dump tree-specific information of block BB to file OUTF. */
2211 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2213 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2217 /* Dump a basic block on stderr. */
2220 debug_tree_bb (basic_block bb
)
2222 dump_bb (bb
, stderr
, 0);
2226 /* Dump basic block with index N on stderr. */
2229 debug_tree_bb_n (int n
)
2231 debug_tree_bb (BASIC_BLOCK (n
));
2232 return BASIC_BLOCK (n
);
2236 /* Dump the CFG on stderr.
2238 FLAGS are the same used by the tree dumping functions
2239 (see TDF_* in tree.h). */
2242 debug_tree_cfg (int flags
)
2244 dump_tree_cfg (stderr
, flags
);
2248 /* Dump the program showing basic block boundaries on the given FILE.
2250 FLAGS are the same used by the tree dumping functions (see TDF_* in
2254 dump_tree_cfg (FILE *file
, int flags
)
2256 if (flags
& TDF_DETAILS
)
2258 const char *funcname
2259 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2262 fprintf (file
, ";; Function %s\n\n", funcname
);
2263 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2264 n_basic_blocks
, n_edges
, last_basic_block
);
2266 brief_dump_cfg (file
);
2267 fprintf (file
, "\n");
2270 if (flags
& TDF_STATS
)
2271 dump_cfg_stats (file
);
2273 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2277 /* Dump CFG statistics on FILE. */
2280 dump_cfg_stats (FILE *file
)
2282 static long max_num_merged_labels
= 0;
2283 unsigned long size
, total
= 0;
2286 const char * const fmt_str
= "%-30s%-13s%12s\n";
2287 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2288 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2289 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2290 const char *funcname
2291 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2294 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2296 fprintf (file
, "---------------------------------------------------------\n");
2297 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2298 fprintf (file
, fmt_str
, "", " instances ", "used ");
2299 fprintf (file
, "---------------------------------------------------------\n");
2301 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2303 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2304 SCALE (size
), LABEL (size
));
2308 num_edges
+= EDGE_COUNT (bb
->succs
);
2309 size
= num_edges
* sizeof (struct edge_def
);
2311 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2313 fprintf (file
, "---------------------------------------------------------\n");
2314 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2316 fprintf (file
, "---------------------------------------------------------\n");
2317 fprintf (file
, "\n");
2319 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2320 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2322 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2323 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2325 fprintf (file
, "\n");
2329 /* Dump CFG statistics on stderr. Keep extern so that it's always
2330 linked in the final executable. */
2333 debug_cfg_stats (void)
2335 dump_cfg_stats (stderr
);
2339 /* Dump the flowgraph to a .vcg FILE. */
2342 tree_cfg2vcg (FILE *file
)
2347 const char *funcname
2348 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2350 /* Write the file header. */
2351 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2352 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2353 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2355 /* Write blocks and edges. */
2356 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2358 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2361 if (e
->flags
& EDGE_FAKE
)
2362 fprintf (file
, " linestyle: dotted priority: 10");
2364 fprintf (file
, " linestyle: solid priority: 100");
2366 fprintf (file
, " }\n");
2372 enum tree_code head_code
, end_code
;
2373 const char *head_name
, *end_name
;
2376 tree first
= first_stmt (bb
);
2377 tree last
= last_stmt (bb
);
2381 head_code
= TREE_CODE (first
);
2382 head_name
= tree_code_name
[head_code
];
2383 head_line
= get_lineno (first
);
2386 head_name
= "no-statement";
2390 end_code
= TREE_CODE (last
);
2391 end_name
= tree_code_name
[end_code
];
2392 end_line
= get_lineno (last
);
2395 end_name
= "no-statement";
2397 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2398 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2401 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2403 if (e
->dest
== EXIT_BLOCK_PTR
)
2404 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2406 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2408 if (e
->flags
& EDGE_FAKE
)
2409 fprintf (file
, " priority: 10 linestyle: dotted");
2411 fprintf (file
, " priority: 100 linestyle: solid");
2413 fprintf (file
, " }\n");
2416 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2420 fputs ("}\n\n", file
);
2425 /*---------------------------------------------------------------------------
2426 Miscellaneous helpers
2427 ---------------------------------------------------------------------------*/
2429 /* Return true if T represents a stmt that always transfers control. */
2432 is_ctrl_stmt (tree t
)
2434 return (TREE_CODE (t
) == COND_EXPR
2435 || TREE_CODE (t
) == SWITCH_EXPR
2436 || TREE_CODE (t
) == GOTO_EXPR
2437 || TREE_CODE (t
) == RETURN_EXPR
2438 || TREE_CODE (t
) == RESX_EXPR
);
2442 /* Return true if T is a statement that may alter the flow of control
2443 (e.g., a call to a non-returning function). */
2446 is_ctrl_altering_stmt (tree t
)
2451 call
= get_call_expr_in (t
);
2454 /* A non-pure/const CALL_EXPR alters flow control if the current
2455 function has nonlocal labels. */
2456 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2459 /* A CALL_EXPR also alters control flow if it does not return. */
2460 if (call_expr_flags (call
) & ECF_NORETURN
)
2464 /* If a statement can throw, it alters control flow. */
2465 return tree_can_throw_internal (t
);
2469 /* Return true if T is a computed goto. */
2472 computed_goto_p (tree t
)
2474 return (TREE_CODE (t
) == GOTO_EXPR
2475 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2479 /* Checks whether EXPR is a simple local goto. */
2482 simple_goto_p (tree expr
)
2484 return (TREE_CODE (expr
) == GOTO_EXPR
2485 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2489 /* Return true if T should start a new basic block. PREV_T is the
2490 statement preceding T. It is used when T is a label or a case label.
2491 Labels should only start a new basic block if their previous statement
2492 wasn't a label. Otherwise, sequence of labels would generate
2493 unnecessary basic blocks that only contain a single label. */
2496 stmt_starts_bb_p (tree t
, tree prev_t
)
2501 /* LABEL_EXPRs start a new basic block only if the preceding
2502 statement wasn't a label of the same type. This prevents the
2503 creation of consecutive blocks that have nothing but a single
2505 if (TREE_CODE (t
) == LABEL_EXPR
)
2507 /* Nonlocal and computed GOTO targets always start a new block. */
2508 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2509 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2512 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2514 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2517 cfg_stats
.num_merged_labels
++;
2528 /* Return true if T should end a basic block. */
2531 stmt_ends_bb_p (tree t
)
2533 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2537 /* Add gotos that used to be represented implicitly in the CFG. */
2540 disband_implicit_edges (void)
2543 block_stmt_iterator last
;
2550 last
= bsi_last (bb
);
2551 stmt
= last_stmt (bb
);
2553 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2555 /* Remove superfluous gotos from COND_EXPR branches. Moved
2556 from cfg_remove_useless_stmts here since it violates the
2557 invariants for tree--cfg correspondence and thus fits better
2558 here where we do it anyway. */
2559 e
= find_edge (bb
, bb
->next_bb
);
2562 if (e
->flags
& EDGE_TRUE_VALUE
)
2563 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2564 else if (e
->flags
& EDGE_FALSE_VALUE
)
2565 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2568 e
->flags
|= EDGE_FALLTHRU
;
2574 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2576 /* Remove the RETURN_EXPR if we may fall though to the exit
2578 gcc_assert (single_succ_p (bb
));
2579 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2581 if (bb
->next_bb
== EXIT_BLOCK_PTR
2582 && !TREE_OPERAND (stmt
, 0))
2585 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2590 /* There can be no fallthru edge if the last statement is a control
2592 if (stmt
&& is_ctrl_stmt (stmt
))
2595 /* Find a fallthru edge and emit the goto if necessary. */
2596 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2597 if (e
->flags
& EDGE_FALLTHRU
)
2600 if (!e
|| e
->dest
== bb
->next_bb
)
2603 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2604 label
= tree_block_label (e
->dest
);
2606 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2607 #ifdef USE_MAPPED_LOCATION
2608 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2610 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2612 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2613 e
->flags
&= ~EDGE_FALLTHRU
;
2617 /* Remove block annotations and other datastructures. */
2620 delete_tree_cfg_annotations (void)
2622 label_to_block_map
= NULL
;
2626 /* Return the first statement in basic block BB. */
2629 first_stmt (basic_block bb
)
2631 block_stmt_iterator i
= bsi_start (bb
);
2632 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2636 /* Return the last statement in basic block BB. */
2639 last_stmt (basic_block bb
)
2641 block_stmt_iterator b
= bsi_last (bb
);
2642 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2646 /* Return a pointer to the last statement in block BB. */
2649 last_stmt_ptr (basic_block bb
)
2651 block_stmt_iterator last
= bsi_last (bb
);
2652 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2656 /* Return the last statement of an otherwise empty block. Return NULL
2657 if the block is totally empty, or if it contains more than one
2661 last_and_only_stmt (basic_block bb
)
2663 block_stmt_iterator i
= bsi_last (bb
);
2669 last
= bsi_stmt (i
);
2674 /* Empty statements should no longer appear in the instruction stream.
2675 Everything that might have appeared before should be deleted by
2676 remove_useless_stmts, and the optimizers should just bsi_remove
2677 instead of smashing with build_empty_stmt.
2679 Thus the only thing that should appear here in a block containing
2680 one executable statement is a label. */
2681 prev
= bsi_stmt (i
);
2682 if (TREE_CODE (prev
) == LABEL_EXPR
)
2689 /* Mark BB as the basic block holding statement T. */
2692 set_bb_for_stmt (tree t
, basic_block bb
)
2694 if (TREE_CODE (t
) == PHI_NODE
)
2696 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2698 tree_stmt_iterator i
;
2699 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2700 set_bb_for_stmt (tsi_stmt (i
), bb
);
2704 stmt_ann_t ann
= get_stmt_ann (t
);
2707 /* If the statement is a label, add the label to block-to-labels map
2708 so that we can speed up edge creation for GOTO_EXPRs. */
2709 if (TREE_CODE (t
) == LABEL_EXPR
)
2713 t
= LABEL_EXPR_LABEL (t
);
2714 uid
= LABEL_DECL_UID (t
);
2717 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2718 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2719 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2722 /* We're moving an existing label. Make sure that we've
2723 removed it from the old block. */
2724 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2725 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2730 /* Finds iterator for STMT. */
2732 extern block_stmt_iterator
2733 bsi_for_stmt (tree stmt
)
2735 block_stmt_iterator bsi
;
2737 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2738 if (bsi_stmt (bsi
) == stmt
)
2744 /* Mark statement T as modified, and update it. */
2746 update_modified_stmts (tree t
)
2748 if (TREE_CODE (t
) == STATEMENT_LIST
)
2750 tree_stmt_iterator i
;
2752 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2754 stmt
= tsi_stmt (i
);
2755 update_stmt_if_modified (stmt
);
2759 update_stmt_if_modified (t
);
2762 /* Insert statement (or statement list) T before the statement
2763 pointed-to by iterator I. M specifies how to update iterator I
2764 after insertion (see enum bsi_iterator_update). */
2767 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2769 set_bb_for_stmt (t
, i
->bb
);
2770 update_modified_stmts (t
);
2771 tsi_link_before (&i
->tsi
, t
, m
);
2775 /* Insert statement (or statement list) T after the statement
2776 pointed-to by iterator I. M specifies how to update iterator I
2777 after insertion (see enum bsi_iterator_update). */
2780 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2782 set_bb_for_stmt (t
, i
->bb
);
2783 update_modified_stmts (t
);
2784 tsi_link_after (&i
->tsi
, t
, m
);
2788 /* Remove the statement pointed to by iterator I. The iterator is updated
2789 to the next statement. */
2792 bsi_remove (block_stmt_iterator
*i
)
2794 tree t
= bsi_stmt (*i
);
2795 set_bb_for_stmt (t
, NULL
);
2796 delink_stmt_imm_use (t
);
2797 tsi_delink (&i
->tsi
);
2798 mark_stmt_modified (t
);
2802 /* Move the statement at FROM so it comes right after the statement at TO. */
2805 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2807 tree stmt
= bsi_stmt (*from
);
2809 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2813 /* Move the statement at FROM so it comes right before the statement at TO. */
2816 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2818 tree stmt
= bsi_stmt (*from
);
2820 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2824 /* Move the statement at FROM to the end of basic block BB. */
2827 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2829 block_stmt_iterator last
= bsi_last (bb
);
2831 /* Have to check bsi_end_p because it could be an empty block. */
2832 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2833 bsi_move_before (from
, &last
);
2835 bsi_move_after (from
, &last
);
2839 /* Replace the contents of the statement pointed to by iterator BSI
2840 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2841 information of the original statement is preserved. */
2844 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2847 tree orig_stmt
= bsi_stmt (*bsi
);
2849 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2850 set_bb_for_stmt (stmt
, bsi
->bb
);
2852 /* Preserve EH region information from the original statement, if
2853 requested by the caller. */
2854 if (preserve_eh_info
)
2856 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2858 add_stmt_to_eh_region (stmt
, eh_region
);
2861 delink_stmt_imm_use (orig_stmt
);
2862 *bsi_stmt_ptr (*bsi
) = stmt
;
2863 mark_stmt_modified (stmt
);
2864 update_modified_stmts (stmt
);
2868 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2869 is made to place the statement in an existing basic block, but
2870 sometimes that isn't possible. When it isn't possible, the edge is
2871 split and the statement is added to the new block.
2873 In all cases, the returned *BSI points to the correct location. The
2874 return value is true if insertion should be done after the location,
2875 or false if it should be done before the location. If new basic block
2876 has to be created, it is stored in *NEW_BB. */
2879 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2880 basic_block
*new_bb
)
2882 basic_block dest
, src
;
2888 /* If the destination has one predecessor which has no PHI nodes,
2889 insert there. Except for the exit block.
2891 The requirement for no PHI nodes could be relaxed. Basically we
2892 would have to examine the PHIs to prove that none of them used
2893 the value set by the statement we want to insert on E. That
2894 hardly seems worth the effort. */
2895 if (single_pred_p (dest
)
2896 && ! phi_nodes (dest
)
2897 && dest
!= EXIT_BLOCK_PTR
)
2899 *bsi
= bsi_start (dest
);
2900 if (bsi_end_p (*bsi
))
2903 /* Make sure we insert after any leading labels. */
2904 tmp
= bsi_stmt (*bsi
);
2905 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2908 if (bsi_end_p (*bsi
))
2910 tmp
= bsi_stmt (*bsi
);
2913 if (bsi_end_p (*bsi
))
2915 *bsi
= bsi_last (dest
);
2922 /* If the source has one successor, the edge is not abnormal and
2923 the last statement does not end a basic block, insert there.
2924 Except for the entry block. */
2926 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2927 && single_succ_p (src
)
2928 && src
!= ENTRY_BLOCK_PTR
)
2930 *bsi
= bsi_last (src
);
2931 if (bsi_end_p (*bsi
))
2934 tmp
= bsi_stmt (*bsi
);
2935 if (!stmt_ends_bb_p (tmp
))
2938 /* Insert code just before returning the value. We may need to decompose
2939 the return in the case it contains non-trivial operand. */
2940 if (TREE_CODE (tmp
) == RETURN_EXPR
)
2942 tree op
= TREE_OPERAND (tmp
, 0);
2943 if (op
&& !is_gimple_val (op
))
2945 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
2946 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
2947 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
2954 /* Otherwise, create a new basic block, and split this edge. */
2955 dest
= split_edge (e
);
2958 e
= single_pred_edge (dest
);
2963 /* This routine will commit all pending edge insertions, creating any new
2964 basic blocks which are necessary. */
2967 bsi_commit_edge_inserts (void)
2973 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
2976 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2977 bsi_commit_one_edge_insert (e
, NULL
);
2981 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2982 to this block, otherwise set it to NULL. */
2985 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
2989 if (PENDING_STMT (e
))
2991 block_stmt_iterator bsi
;
2992 tree stmt
= PENDING_STMT (e
);
2994 PENDING_STMT (e
) = NULL_TREE
;
2996 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
2997 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
2999 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3004 /* Add STMT to the pending list of edge E. No actual insertion is
3005 made until a call to bsi_commit_edge_inserts () is made. */
3008 bsi_insert_on_edge (edge e
, tree stmt
)
3010 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3013 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3014 block has to be created, it is returned. */
3017 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3019 block_stmt_iterator bsi
;
3020 basic_block new_bb
= NULL
;
3022 gcc_assert (!PENDING_STMT (e
));
3024 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3025 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3027 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3032 /*---------------------------------------------------------------------------
3033 Tree specific functions for CFG manipulation
3034 ---------------------------------------------------------------------------*/
3036 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3039 reinstall_phi_args (edge new_edge
, edge old_edge
)
3043 if (!PENDING_STMT (old_edge
))
3046 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3048 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3050 tree result
= TREE_PURPOSE (var
);
3051 tree arg
= TREE_VALUE (var
);
3053 gcc_assert (result
== PHI_RESULT (phi
));
3055 add_phi_arg (phi
, arg
, new_edge
);
3058 PENDING_STMT (old_edge
) = NULL
;
3061 /* Returns the basic block after that the new basic block created
3062 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3063 near its "logical" location. This is of most help to humans looking
3064 at debugging dumps. */
3067 split_edge_bb_loc (edge edge_in
)
3069 basic_block dest
= edge_in
->dest
;
3071 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3072 return edge_in
->src
;
3074 return dest
->prev_bb
;
3077 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3078 Abort on abnormal edges. */
3081 tree_split_edge (edge edge_in
)
3083 basic_block new_bb
, after_bb
, dest
, src
;
3086 /* Abnormal edges cannot be split. */
3087 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3090 dest
= edge_in
->dest
;
3092 after_bb
= split_edge_bb_loc (edge_in
);
3094 new_bb
= create_empty_bb (after_bb
);
3095 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3096 new_bb
->count
= edge_in
->count
;
3097 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3098 new_edge
->probability
= REG_BR_PROB_BASE
;
3099 new_edge
->count
= edge_in
->count
;
3101 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3103 reinstall_phi_args (new_edge
, e
);
3109 /* Return true when BB has label LABEL in it. */
3112 has_label_p (basic_block bb
, tree label
)
3114 block_stmt_iterator bsi
;
3116 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3118 tree stmt
= bsi_stmt (bsi
);
3120 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3122 if (LABEL_EXPR_LABEL (stmt
) == label
)
3129 /* Callback for walk_tree, check that all elements with address taken are
3130 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3131 inside a PHI node. */
3134 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3137 bool in_phi
= (data
!= NULL
);
3142 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3143 #define CHECK_OP(N, MSG) \
3144 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3145 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3147 switch (TREE_CODE (t
))
3150 if (SSA_NAME_IN_FREE_LIST (t
))
3152 error ("SSA name in freelist but still referenced");
3158 x
= fold (ASSERT_EXPR_COND (t
));
3159 if (x
== boolean_false_node
)
3161 error ("ASSERT_EXPR with an always-false condition");
3167 x
= TREE_OPERAND (t
, 0);
3168 if (TREE_CODE (x
) == BIT_FIELD_REF
3169 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3171 error ("GIMPLE register modified with BIT_FIELD_REF");
3180 bool old_side_effects
;
3183 bool new_side_effects
;
3185 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3186 dead PHIs that take the address of something. But if the PHI
3187 result is dead, the fact that it takes the address of anything
3188 is irrelevant. Because we can not tell from here if a PHI result
3189 is dead, we just skip this check for PHIs altogether. This means
3190 we may be missing "valid" checks, but what can you do?
3191 This was PR19217. */
3195 old_invariant
= TREE_INVARIANT (t
);
3196 old_constant
= TREE_CONSTANT (t
);
3197 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3199 recompute_tree_invariant_for_addr_expr (t
);
3200 new_invariant
= TREE_INVARIANT (t
);
3201 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3202 new_constant
= TREE_CONSTANT (t
);
3204 if (old_invariant
!= new_invariant
)
3206 error ("invariant not recomputed when ADDR_EXPR changed");
3210 if (old_constant
!= new_constant
)
3212 error ("constant not recomputed when ADDR_EXPR changed");
3215 if (old_side_effects
!= new_side_effects
)
3217 error ("side effects not recomputed when ADDR_EXPR changed");
3221 /* Skip any references (they will be checked when we recurse down the
3222 tree) and ensure that any variable used as a prefix is marked
3224 for (x
= TREE_OPERAND (t
, 0);
3225 handled_component_p (x
);
3226 x
= TREE_OPERAND (x
, 0))
3229 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3231 if (!TREE_ADDRESSABLE (x
))
3233 error ("address taken, but ADDRESSABLE bit not set");
3240 x
= COND_EXPR_COND (t
);
3241 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3243 error ("non-boolean used in condition");
3246 if (!is_gimple_condexpr (x
))
3248 error ("invalid conditional operand");
3255 case FIX_TRUNC_EXPR
:
3257 case FIX_FLOOR_EXPR
:
3258 case FIX_ROUND_EXPR
:
3263 case NON_LVALUE_EXPR
:
3264 case TRUTH_NOT_EXPR
:
3265 CHECK_OP (0, "invalid operand to unary operator");
3272 case ARRAY_RANGE_REF
:
3274 case VIEW_CONVERT_EXPR
:
3275 /* We have a nest of references. Verify that each of the operands
3276 that determine where to reference is either a constant or a variable,
3277 verify that the base is valid, and then show we've already checked
3279 while (handled_component_p (t
))
3281 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3282 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3283 else if (TREE_CODE (t
) == ARRAY_REF
3284 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3286 CHECK_OP (1, "invalid array index");
3287 if (TREE_OPERAND (t
, 2))
3288 CHECK_OP (2, "invalid array lower bound");
3289 if (TREE_OPERAND (t
, 3))
3290 CHECK_OP (3, "invalid array stride");
3292 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3294 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3295 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3298 t
= TREE_OPERAND (t
, 0);
3301 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3303 error ("invalid reference prefix");
3315 case UNORDERED_EXPR
:
3326 case TRUNC_DIV_EXPR
:
3328 case FLOOR_DIV_EXPR
:
3329 case ROUND_DIV_EXPR
:
3330 case TRUNC_MOD_EXPR
:
3332 case FLOOR_MOD_EXPR
:
3333 case ROUND_MOD_EXPR
:
3335 case EXACT_DIV_EXPR
:
3345 CHECK_OP (0, "invalid operand to binary operator");
3346 CHECK_OP (1, "invalid operand to binary operator");
3358 /* Verify STMT, return true if STMT is not in GIMPLE form.
3359 TODO: Implement type checking. */
3362 verify_stmt (tree stmt
, bool last_in_block
)
3366 if (!is_gimple_stmt (stmt
))
3368 error ("is not a valid GIMPLE statement");
3372 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3375 debug_generic_stmt (addr
);
3379 /* If the statement is marked as part of an EH region, then it is
3380 expected that the statement could throw. Verify that when we
3381 have optimizations that simplify statements such that we prove
3382 that they cannot throw, that we update other data structures
3384 if (lookup_stmt_eh_region (stmt
) >= 0)
3386 if (!tree_could_throw_p (stmt
))
3388 error ("statement marked for throw, but doesn%'t");
3391 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3393 error ("statement marked for throw in middle of block");
3401 debug_generic_stmt (stmt
);
3406 /* Return true when the T can be shared. */
3409 tree_node_can_be_shared (tree t
)
3411 if (IS_TYPE_OR_DECL_P (t
)
3412 /* We check for constants explicitly since they are not considered
3413 gimple invariants if they overflowed. */
3414 || CONSTANT_CLASS_P (t
)
3415 || is_gimple_min_invariant (t
)
3416 || TREE_CODE (t
) == SSA_NAME
3417 || t
== error_mark_node
)
3420 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3423 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3424 /* We check for constants explicitly since they are not considered
3425 gimple invariants if they overflowed. */
3426 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3427 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3428 || (TREE_CODE (t
) == COMPONENT_REF
3429 || TREE_CODE (t
) == REALPART_EXPR
3430 || TREE_CODE (t
) == IMAGPART_EXPR
))
3431 t
= TREE_OPERAND (t
, 0);
3440 /* Called via walk_trees. Verify tree sharing. */
3443 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3445 htab_t htab
= (htab_t
) data
;
3448 if (tree_node_can_be_shared (*tp
))
3450 *walk_subtrees
= false;
3454 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3456 return (tree
) *slot
;
3463 /* Verify the GIMPLE statement chain. */
3469 block_stmt_iterator bsi
;
3474 timevar_push (TV_TREE_STMT_VERIFY
);
3475 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3482 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3484 int phi_num_args
= PHI_NUM_ARGS (phi
);
3486 if (bb_for_stmt (phi
) != bb
)
3488 error ("bb_for_stmt (phi) is set to a wrong basic block");
3492 for (i
= 0; i
< phi_num_args
; i
++)
3494 tree t
= PHI_ARG_DEF (phi
, i
);
3497 /* Addressable variables do have SSA_NAMEs but they
3498 are not considered gimple values. */
3499 if (TREE_CODE (t
) != SSA_NAME
3500 && TREE_CODE (t
) != FUNCTION_DECL
3501 && !is_gimple_val (t
))
3503 error ("PHI def is not a GIMPLE value");
3504 debug_generic_stmt (phi
);
3505 debug_generic_stmt (t
);
3509 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3512 debug_generic_stmt (addr
);
3516 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3519 error ("incorrect sharing of tree nodes");
3520 debug_generic_stmt (phi
);
3521 debug_generic_stmt (addr
);
3527 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3529 tree stmt
= bsi_stmt (bsi
);
3531 if (bb_for_stmt (stmt
) != bb
)
3533 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3538 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3539 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3542 error ("incorrect sharing of tree nodes");
3543 debug_generic_stmt (stmt
);
3544 debug_generic_stmt (addr
);
3551 internal_error ("verify_stmts failed");
3554 timevar_pop (TV_TREE_STMT_VERIFY
);
3558 /* Verifies that the flow information is OK. */
3561 tree_verify_flow_info (void)
3565 block_stmt_iterator bsi
;
3570 if (ENTRY_BLOCK_PTR
->stmt_list
)
3572 error ("ENTRY_BLOCK has a statement list associated with it");
3576 if (EXIT_BLOCK_PTR
->stmt_list
)
3578 error ("EXIT_BLOCK has a statement list associated with it");
3582 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3583 if (e
->flags
& EDGE_FALLTHRU
)
3585 error ("fallthru to exit from bb %d", e
->src
->index
);
3591 bool found_ctrl_stmt
= false;
3595 /* Skip labels on the start of basic block. */
3596 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3598 tree prev_stmt
= stmt
;
3600 stmt
= bsi_stmt (bsi
);
3602 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3605 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3607 error ("nonlocal label %s is not first "
3608 "in a sequence of labels in bb %d",
3609 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3614 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3616 error ("label %s to block does not match in bb %d",
3617 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3622 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3623 != current_function_decl
)
3625 error ("label %s has incorrect context in bb %d",
3626 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3632 /* Verify that body of basic block BB is free of control flow. */
3633 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3635 tree stmt
= bsi_stmt (bsi
);
3637 if (found_ctrl_stmt
)
3639 error ("control flow in the middle of basic block %d",
3644 if (stmt_ends_bb_p (stmt
))
3645 found_ctrl_stmt
= true;
3647 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3649 error ("label %s in the middle of basic block %d",
3650 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3655 bsi
= bsi_last (bb
);
3656 if (bsi_end_p (bsi
))
3659 stmt
= bsi_stmt (bsi
);
3661 err
|= verify_eh_edges (stmt
);
3663 if (is_ctrl_stmt (stmt
))
3665 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3666 if (e
->flags
& EDGE_FALLTHRU
)
3668 error ("fallthru edge after a control statement in bb %d",
3674 switch (TREE_CODE (stmt
))
3680 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3681 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3683 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3687 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3689 if (!true_edge
|| !false_edge
3690 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3691 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3692 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3693 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3694 || EDGE_COUNT (bb
->succs
) >= 3)
3696 error ("wrong outgoing edge flags at end of bb %d",
3701 if (!has_label_p (true_edge
->dest
,
3702 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3704 error ("%<then%> label does not match edge at end of bb %d",
3709 if (!has_label_p (false_edge
->dest
,
3710 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3712 error ("%<else%> label does not match edge at end of bb %d",
3720 if (simple_goto_p (stmt
))
3722 error ("explicit goto at end of bb %d", bb
->index
);
3727 /* FIXME. We should double check that the labels in the
3728 destination blocks have their address taken. */
3729 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3730 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3731 | EDGE_FALSE_VALUE
))
3732 || !(e
->flags
& EDGE_ABNORMAL
))
3734 error ("wrong outgoing edge flags at end of bb %d",
3742 if (!single_succ_p (bb
)
3743 || (single_succ_edge (bb
)->flags
3744 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3745 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3747 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3750 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3752 error ("return edge does not point to exit in bb %d",
3765 vec
= SWITCH_LABELS (stmt
);
3766 n
= TREE_VEC_LENGTH (vec
);
3768 /* Mark all the destination basic blocks. */
3769 for (i
= 0; i
< n
; ++i
)
3771 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3772 basic_block label_bb
= label_to_block (lab
);
3774 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3775 label_bb
->aux
= (void *)1;
3778 /* Verify that the case labels are sorted. */
3779 prev
= TREE_VEC_ELT (vec
, 0);
3780 for (i
= 1; i
< n
- 1; ++i
)
3782 tree c
= TREE_VEC_ELT (vec
, i
);
3785 error ("found default case not at end of case vector");
3789 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3791 error ("case labels not sorted:");
3792 print_generic_expr (stderr
, prev
, 0);
3793 fprintf (stderr
," is greater than ");
3794 print_generic_expr (stderr
, c
, 0);
3795 fprintf (stderr
," but comes before it.\n");
3800 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3802 error ("no default case found at end of case vector");
3806 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3810 error ("extra outgoing edge %d->%d",
3811 bb
->index
, e
->dest
->index
);
3814 e
->dest
->aux
= (void *)2;
3815 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3816 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3818 error ("wrong outgoing edge flags at end of bb %d",
3824 /* Check that we have all of them. */
3825 for (i
= 0; i
< n
; ++i
)
3827 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3828 basic_block label_bb
= label_to_block (lab
);
3830 if (label_bb
->aux
!= (void *)2)
3832 error ("missing edge %i->%i",
3833 bb
->index
, label_bb
->index
);
3838 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3839 e
->dest
->aux
= (void *)0;
3846 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3847 verify_dominators (CDI_DOMINATORS
);
3853 /* Updates phi nodes after creating a forwarder block joined
3854 by edge FALLTHRU. */
3857 tree_make_forwarder_block (edge fallthru
)
3861 basic_block dummy
, bb
;
3862 tree phi
, new_phi
, var
;
3864 dummy
= fallthru
->src
;
3865 bb
= fallthru
->dest
;
3867 if (single_pred_p (bb
))
3870 /* If we redirected a branch we must create new phi nodes at the
3872 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3874 var
= PHI_RESULT (phi
);
3875 new_phi
= create_phi_node (var
, bb
);
3876 SSA_NAME_DEF_STMT (var
) = new_phi
;
3877 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3878 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3881 /* Ensure that the PHI node chain is in the same order. */
3882 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3884 /* Add the arguments we have stored on edges. */
3885 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3890 flush_pending_stmts (e
);
3895 /* Return a non-special label in the head of basic block BLOCK.
3896 Create one if it doesn't exist. */
3899 tree_block_label (basic_block bb
)
3901 block_stmt_iterator i
, s
= bsi_start (bb
);
3905 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3907 stmt
= bsi_stmt (i
);
3908 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3910 label
= LABEL_EXPR_LABEL (stmt
);
3911 if (!DECL_NONLOCAL (label
))
3914 bsi_move_before (&i
, &s
);
3919 label
= create_artificial_label ();
3920 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3921 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3926 /* Attempt to perform edge redirection by replacing a possibly complex
3927 jump instruction by a goto or by removing the jump completely.
3928 This can apply only if all edges now point to the same block. The
3929 parameters and return values are equivalent to
3930 redirect_edge_and_branch. */
3933 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
3935 basic_block src
= e
->src
;
3936 block_stmt_iterator b
;
3939 /* We can replace or remove a complex jump only when we have exactly
3941 if (EDGE_COUNT (src
->succs
) != 2
3942 /* Verify that all targets will be TARGET. Specifically, the
3943 edge that is not E must also go to TARGET. */
3944 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
3950 stmt
= bsi_stmt (b
);
3952 if (TREE_CODE (stmt
) == COND_EXPR
3953 || TREE_CODE (stmt
) == SWITCH_EXPR
)
3956 e
= ssa_redirect_edge (e
, target
);
3957 e
->flags
= EDGE_FALLTHRU
;
3965 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3966 edge representing the redirected branch. */
3969 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
3971 basic_block bb
= e
->src
;
3972 block_stmt_iterator bsi
;
3976 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3979 if (e
->src
!= ENTRY_BLOCK_PTR
3980 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
3983 if (e
->dest
== dest
)
3986 label
= tree_block_label (dest
);
3988 bsi
= bsi_last (bb
);
3989 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
3991 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
3994 stmt
= (e
->flags
& EDGE_TRUE_VALUE
3995 ? COND_EXPR_THEN (stmt
)
3996 : COND_EXPR_ELSE (stmt
));
3997 GOTO_DESTINATION (stmt
) = label
;
4001 /* No non-abnormal edges should lead from a non-simple goto, and
4002 simple ones should be represented implicitly. */
4007 tree cases
= get_cases_for_edge (e
, stmt
);
4009 /* If we have a list of cases associated with E, then use it
4010 as it's a lot faster than walking the entire case vector. */
4013 edge e2
= find_edge (e
->src
, dest
);
4020 CASE_LABEL (cases
) = label
;
4021 cases
= TREE_CHAIN (cases
);
4024 /* If there was already an edge in the CFG, then we need
4025 to move all the cases associated with E to E2. */
4028 tree cases2
= get_cases_for_edge (e2
, stmt
);
4030 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4031 TREE_CHAIN (cases2
) = first
;
4036 tree vec
= SWITCH_LABELS (stmt
);
4037 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4039 for (i
= 0; i
< n
; i
++)
4041 tree elt
= TREE_VEC_ELT (vec
, i
);
4043 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4044 CASE_LABEL (elt
) = label
;
4053 e
->flags
|= EDGE_FALLTHRU
;
4057 /* Otherwise it must be a fallthru edge, and we don't need to
4058 do anything besides redirecting it. */
4059 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4063 /* Update/insert PHI nodes as necessary. */
4065 /* Now update the edges in the CFG. */
4066 e
= ssa_redirect_edge (e
, dest
);
4072 /* Simple wrapper, as we can always redirect fallthru edges. */
4075 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4077 e
= tree_redirect_edge_and_branch (e
, dest
);
4084 /* Splits basic block BB after statement STMT (but at least after the
4085 labels). If STMT is NULL, BB is split just after the labels. */
4088 tree_split_block (basic_block bb
, void *stmt
)
4090 block_stmt_iterator bsi
, bsi_tgt
;
4096 new_bb
= create_empty_bb (bb
);
4098 /* Redirect the outgoing edges. */
4099 new_bb
->succs
= bb
->succs
;
4101 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4104 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4107 /* Move everything from BSI to the new basic block. */
4108 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4110 act
= bsi_stmt (bsi
);
4111 if (TREE_CODE (act
) == LABEL_EXPR
)
4124 bsi_tgt
= bsi_start (new_bb
);
4125 while (!bsi_end_p (bsi
))
4127 act
= bsi_stmt (bsi
);
4129 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4136 /* Moves basic block BB after block AFTER. */
4139 tree_move_block_after (basic_block bb
, basic_block after
)
4141 if (bb
->prev_bb
== after
)
4145 link_block (bb
, after
);
4151 /* Return true if basic_block can be duplicated. */
4154 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4160 /* Create a duplicate of the basic block BB. NOTE: This does not
4161 preserve SSA form. */
4164 tree_duplicate_bb (basic_block bb
)
4167 block_stmt_iterator bsi
, bsi_tgt
;
4170 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4172 /* Copy the PHI nodes. We ignore PHI node arguments here because
4173 the incoming edges have not been setup yet. */
4174 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4176 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4177 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4180 /* Keep the chain of PHI nodes in the same order so that they can be
4181 updated by ssa_redirect_edge. */
4182 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4184 bsi_tgt
= bsi_start (new_bb
);
4185 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4187 def_operand_p def_p
;
4188 ssa_op_iter op_iter
;
4192 stmt
= bsi_stmt (bsi
);
4193 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4196 /* Create a new copy of STMT and duplicate STMT's virtual
4198 copy
= unshare_expr (stmt
);
4199 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4200 copy_virtual_operands (copy
, stmt
);
4201 region
= lookup_stmt_eh_region (stmt
);
4203 add_stmt_to_eh_region (copy
, region
);
4205 /* Create new names for all the definitions created by COPY and
4206 add replacement mappings for each new name. */
4207 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4208 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4215 /* Basic block BB_COPY was created by code duplication. Add phi node
4216 arguments for edges going out of BB_COPY. The blocks that were
4217 duplicated have BB_DUPLICATED set. */
4220 add_phi_args_after_copy_bb (basic_block bb_copy
)
4222 basic_block bb
, dest
;
4225 tree phi
, phi_copy
, phi_next
, def
;
4227 bb
= get_bb_original (bb_copy
);
4229 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4231 if (!phi_nodes (e_copy
->dest
))
4234 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4235 dest
= get_bb_original (e_copy
->dest
);
4237 dest
= e_copy
->dest
;
4239 e
= find_edge (bb
, dest
);
4242 /* During loop unrolling the target of the latch edge is copied.
4243 In this case we are not looking for edge to dest, but to
4244 duplicated block whose original was dest. */
4245 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4246 if ((e
->dest
->flags
& BB_DUPLICATED
)
4247 && get_bb_original (e
->dest
) == dest
)
4250 gcc_assert (e
!= NULL
);
4253 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4255 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4257 phi_next
= PHI_CHAIN (phi
);
4258 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4259 add_phi_arg (phi_copy
, def
, e_copy
);
4264 /* Blocks in REGION_COPY array of length N_REGION were created by
4265 duplication of basic blocks. Add phi node arguments for edges
4266 going from these blocks. */
4269 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4273 for (i
= 0; i
< n_region
; i
++)
4274 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4276 for (i
= 0; i
< n_region
; i
++)
4277 add_phi_args_after_copy_bb (region_copy
[i
]);
4279 for (i
= 0; i
< n_region
; i
++)
4280 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4283 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4284 important exit edge EXIT. By important we mean that no SSA name defined
4285 inside region is live over the other exit edges of the region. All entry
4286 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4287 to the duplicate of the region. SSA form, dominance and loop information
4288 is updated. The new basic blocks are stored to REGION_COPY in the same
4289 order as they had in REGION, provided that REGION_COPY is not NULL.
4290 The function returns false if it is unable to copy the region,
4294 tree_duplicate_sese_region (edge entry
, edge exit
,
4295 basic_block
*region
, unsigned n_region
,
4296 basic_block
*region_copy
)
4299 bool free_region_copy
= false, copying_header
= false;
4300 struct loop
*loop
= entry
->dest
->loop_father
;
4304 int total_freq
= 0, entry_freq
= 0;
4305 gcov_type total_count
= 0, entry_count
= 0;
4307 if (!can_copy_bbs_p (region
, n_region
))
4310 /* Some sanity checking. Note that we do not check for all possible
4311 missuses of the functions. I.e. if you ask to copy something weird,
4312 it will work, but the state of structures probably will not be
4314 for (i
= 0; i
< n_region
; i
++)
4316 /* We do not handle subloops, i.e. all the blocks must belong to the
4318 if (region
[i
]->loop_father
!= loop
)
4321 if (region
[i
] != entry
->dest
4322 && region
[i
] == loop
->header
)
4328 /* In case the function is used for loop header copying (which is the primary
4329 use), ensure that EXIT and its copy will be new latch and entry edges. */
4330 if (loop
->header
== entry
->dest
)
4332 copying_header
= true;
4333 loop
->copy
= loop
->outer
;
4335 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4338 for (i
= 0; i
< n_region
; i
++)
4339 if (region
[i
] != exit
->src
4340 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4346 region_copy
= XNEWVEC (basic_block
, n_region
);
4347 free_region_copy
= true;
4350 gcc_assert (!need_ssa_update_p ());
4352 /* Record blocks outside the region that are dominated by something
4354 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4355 initialize_original_copy_tables ();
4357 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4359 if (entry
->dest
->count
)
4361 total_count
= entry
->dest
->count
;
4362 entry_count
= entry
->count
;
4363 /* Fix up corner cases, to avoid division by zero or creation of negative
4365 if (entry_count
> total_count
)
4366 entry_count
= total_count
;
4370 total_freq
= entry
->dest
->frequency
;
4371 entry_freq
= EDGE_FREQUENCY (entry
);
4372 /* Fix up corner cases, to avoid division by zero or creation of negative
4374 if (total_freq
== 0)
4376 else if (entry_freq
> total_freq
)
4377 entry_freq
= total_freq
;
4380 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4381 split_edge_bb_loc (entry
));
4384 scale_bbs_frequencies_gcov_type (region
, n_region
,
4385 total_count
- entry_count
,
4387 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4392 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4394 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4399 loop
->header
= exit
->dest
;
4400 loop
->latch
= exit
->src
;
4403 /* Redirect the entry and add the phi node arguments. */
4404 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4405 gcc_assert (redirected
!= NULL
);
4406 flush_pending_stmts (entry
);
4408 /* Concerning updating of dominators: We must recount dominators
4409 for entry block and its copy. Anything that is outside of the
4410 region, but was dominated by something inside needs recounting as
4412 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4413 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4414 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4417 /* Add the other PHI node arguments. */
4418 add_phi_args_after_copy (region_copy
, n_region
);
4420 /* Update the SSA web. */
4421 update_ssa (TODO_update_ssa
);
4423 if (free_region_copy
)
4426 free_original_copy_tables ();
4431 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4434 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4436 tree arg
, vars
, var
;
4437 bool ignore_topmost_bind
= false, any_var
= false;
4441 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4443 arg
= DECL_ARGUMENTS (fn
);
4446 print_generic_expr (file
, arg
, dump_flags
);
4447 if (TREE_CHAIN (arg
))
4448 fprintf (file
, ", ");
4449 arg
= TREE_CHAIN (arg
);
4451 fprintf (file
, ")\n");
4453 if (flags
& TDF_DETAILS
)
4454 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4455 if (flags
& TDF_RAW
)
4457 dump_node (fn
, TDF_SLIM
| flags
, file
);
4461 /* When GIMPLE is lowered, the variables are no longer available in
4462 BIND_EXPRs, so display them separately. */
4463 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4465 ignore_topmost_bind
= true;
4467 fprintf (file
, "{\n");
4468 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4470 var
= TREE_VALUE (vars
);
4472 print_generic_decl (file
, var
, flags
);
4473 fprintf (file
, "\n");
4479 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4481 /* Make a CFG based dump. */
4482 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4483 if (!ignore_topmost_bind
)
4484 fprintf (file
, "{\n");
4486 if (any_var
&& n_basic_blocks
)
4487 fprintf (file
, "\n");
4490 dump_generic_bb (file
, bb
, 2, flags
);
4492 fprintf (file
, "}\n");
4493 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4499 /* Make a tree based dump. */
4500 chain
= DECL_SAVED_TREE (fn
);
4502 if (TREE_CODE (chain
) == BIND_EXPR
)
4504 if (ignore_topmost_bind
)
4506 chain
= BIND_EXPR_BODY (chain
);
4514 if (!ignore_topmost_bind
)
4515 fprintf (file
, "{\n");
4520 fprintf (file
, "\n");
4522 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4523 if (ignore_topmost_bind
)
4524 fprintf (file
, "}\n");
4527 fprintf (file
, "\n\n");
4531 /* Pretty print of the loops intermediate representation. */
4532 static void print_loop (FILE *, struct loop
*, int);
4533 static void print_pred_bbs (FILE *, basic_block bb
);
4534 static void print_succ_bbs (FILE *, basic_block bb
);
4537 /* Print on FILE the indexes for the predecessors of basic_block BB. */
4540 print_pred_bbs (FILE *file
, basic_block bb
)
4545 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4546 fprintf (file
, "bb_%d ", e
->src
->index
);
4550 /* Print on FILE the indexes for the successors of basic_block BB. */
4553 print_succ_bbs (FILE *file
, basic_block bb
)
4558 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4559 fprintf (file
, "bb_%d ", e
->dest
->index
);
4563 /* Pretty print LOOP on FILE, indented INDENT spaces. */
4566 print_loop (FILE *file
, struct loop
*loop
, int indent
)
4574 s_indent
= (char *) alloca ((size_t) indent
+ 1);
4575 memset ((void *) s_indent
, ' ', (size_t) indent
);
4576 s_indent
[indent
] = '\0';
4578 /* Print the loop's header. */
4579 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
4581 /* Print the loop's body. */
4582 fprintf (file
, "%s{\n", s_indent
);
4584 if (bb
->loop_father
== loop
)
4586 /* Print the basic_block's header. */
4587 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
4588 print_pred_bbs (file
, bb
);
4589 fprintf (file
, "}, succs = {");
4590 print_succ_bbs (file
, bb
);
4591 fprintf (file
, "})\n");
4593 /* Print the basic_block's body. */
4594 fprintf (file
, "%s {\n", s_indent
);
4595 tree_dump_bb (bb
, file
, indent
+ 4);
4596 fprintf (file
, "%s }\n", s_indent
);
4599 print_loop (file
, loop
->inner
, indent
+ 2);
4600 fprintf (file
, "%s}\n", s_indent
);
4601 print_loop (file
, loop
->next
, indent
);
4605 /* Follow a CFG edge from the entry point of the program, and on entry
4606 of a loop, pretty print the loop structure on FILE. */
4609 print_loop_ir (FILE *file
)
4613 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
4614 if (bb
&& bb
->loop_father
)
4615 print_loop (file
, bb
->loop_father
, 0);
4619 /* Debugging loops structure at tree level. */
4622 debug_loop_ir (void)
4624 print_loop_ir (stderr
);
4628 /* Return true if BB ends with a call, possibly followed by some
4629 instructions that must stay with the call. Return false,
4633 tree_block_ends_with_call_p (basic_block bb
)
4635 block_stmt_iterator bsi
= bsi_last (bb
);
4636 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
4640 /* Return true if BB ends with a conditional branch. Return false,
4644 tree_block_ends_with_condjump_p (basic_block bb
)
4646 tree stmt
= last_stmt (bb
);
4647 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
4651 /* Return true if we need to add fake edge to exit at statement T.
4652 Helper function for tree_flow_call_edges_add. */
4655 need_fake_edge_p (tree t
)
4659 /* NORETURN and LONGJMP calls already have an edge to exit.
4660 CONST and PURE calls do not need one.
4661 We don't currently check for CONST and PURE here, although
4662 it would be a good idea, because those attributes are
4663 figured out from the RTL in mark_constant_function, and
4664 the counter incrementation code from -fprofile-arcs
4665 leads to different results from -fbranch-probabilities. */
4666 call
= get_call_expr_in (t
);
4668 && !(call_expr_flags (call
) & ECF_NORETURN
))
4671 if (TREE_CODE (t
) == ASM_EXPR
4672 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
4679 /* Add fake edges to the function exit for any non constant and non
4680 noreturn calls, volatile inline assembly in the bitmap of blocks
4681 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
4682 the number of blocks that were split.
4684 The goal is to expose cases in which entering a basic block does
4685 not imply that all subsequent instructions must be executed. */
4688 tree_flow_call_edges_add (sbitmap blocks
)
4691 int blocks_split
= 0;
4692 int last_bb
= last_basic_block
;
4693 bool check_last_block
= false;
4695 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
4699 check_last_block
= true;
4701 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
4703 /* In the last basic block, before epilogue generation, there will be
4704 a fallthru edge to EXIT. Special care is required if the last insn
4705 of the last basic block is a call because make_edge folds duplicate
4706 edges, which would result in the fallthru edge also being marked
4707 fake, which would result in the fallthru edge being removed by
4708 remove_fake_edges, which would result in an invalid CFG.
4710 Moreover, we can't elide the outgoing fake edge, since the block
4711 profiler needs to take this into account in order to solve the minimal
4712 spanning tree in the case that the call doesn't return.
4714 Handle this by adding a dummy instruction in a new last basic block. */
4715 if (check_last_block
)
4717 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
4718 block_stmt_iterator bsi
= bsi_last (bb
);
4720 if (!bsi_end_p (bsi
))
4723 if (t
&& need_fake_edge_p (t
))
4727 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4730 bsi_insert_on_edge (e
, build_empty_stmt ());
4731 bsi_commit_edge_inserts ();
4736 /* Now add fake edges to the function exit for any non constant
4737 calls since there is no way that we can determine if they will
4739 for (i
= 0; i
< last_bb
; i
++)
4741 basic_block bb
= BASIC_BLOCK (i
);
4742 block_stmt_iterator bsi
;
4743 tree stmt
, last_stmt
;
4748 if (blocks
&& !TEST_BIT (blocks
, i
))
4751 bsi
= bsi_last (bb
);
4752 if (!bsi_end_p (bsi
))
4754 last_stmt
= bsi_stmt (bsi
);
4757 stmt
= bsi_stmt (bsi
);
4758 if (need_fake_edge_p (stmt
))
4761 /* The handling above of the final block before the
4762 epilogue should be enough to verify that there is
4763 no edge to the exit block in CFG already.
4764 Calling make_edge in such case would cause us to
4765 mark that edge as fake and remove it later. */
4766 #ifdef ENABLE_CHECKING
4767 if (stmt
== last_stmt
)
4769 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4770 gcc_assert (e
== NULL
);
4774 /* Note that the following may create a new basic block
4775 and renumber the existing basic blocks. */
4776 if (stmt
!= last_stmt
)
4778 e
= split_block (bb
, stmt
);
4782 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
4786 while (!bsi_end_p (bsi
));
4791 verify_flow_info ();
4793 return blocks_split
;
4797 tree_purge_dead_eh_edges (basic_block bb
)
4799 bool changed
= false;
4802 tree stmt
= last_stmt (bb
);
4804 if (stmt
&& tree_can_throw_internal (stmt
))
4807 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
4809 if (e
->flags
& EDGE_EH
)
4818 /* Removal of dead EH edges might change dominators of not
4819 just immediate successors. E.g. when bb1 is changed so that
4820 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
4821 eh edges purged by this function in:
4833 idom(bb5) must be recomputed. For now just free the dominance
4836 free_dominance_info (CDI_DOMINATORS
);
4842 tree_purge_all_dead_eh_edges (bitmap blocks
)
4844 bool changed
= false;
4848 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
4850 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
4856 /* This function is called whenever a new edge is created or
4860 tree_execute_on_growing_pred (edge e
)
4862 basic_block bb
= e
->dest
;
4865 reserve_phi_args_for_new_edge (bb
);
4868 /* This function is called immediately before edge E is removed from
4869 the edge vector E->dest->preds. */
4872 tree_execute_on_shrinking_pred (edge e
)
4874 if (phi_nodes (e
->dest
))
4875 remove_phi_args (e
);
4878 /*---------------------------------------------------------------------------
4879 Helper functions for Loop versioning
4880 ---------------------------------------------------------------------------*/
4882 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
4883 of 'first'. Both of them are dominated by 'new_head' basic block. When
4884 'new_head' was created by 'second's incoming edge it received phi arguments
4885 on the edge by split_edge(). Later, additional edge 'e' was created to
4886 connect 'new_head' and 'first'. Now this routine adds phi args on this
4887 additional edge 'e' that new_head to second edge received as part of edge
4892 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
4893 basic_block new_head
, edge e
)
4896 edge e2
= find_edge (new_head
, second
);
4898 /* Because NEW_HEAD has been created by splitting SECOND's incoming
4899 edge, we should always have an edge from NEW_HEAD to SECOND. */
4900 gcc_assert (e2
!= NULL
);
4902 /* Browse all 'second' basic block phi nodes and add phi args to
4903 edge 'e' for 'first' head. PHI args are always in correct order. */
4905 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
4907 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
4909 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
4910 add_phi_arg (phi1
, def
, e
);
4914 /* Adds a if else statement to COND_BB with condition COND_EXPR.
4915 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
4916 the destination of the ELSE part. */
4918 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
4919 basic_block cond_bb
, void *cond_e
)
4921 block_stmt_iterator bsi
;
4922 tree goto1
= NULL_TREE
;
4923 tree goto2
= NULL_TREE
;
4924 tree new_cond_expr
= NULL_TREE
;
4925 tree cond_expr
= (tree
) cond_e
;
4928 /* Build new conditional expr */
4929 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
4930 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
4931 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
4933 /* Add new cond in cond_bb. */
4934 bsi
= bsi_start (cond_bb
);
4935 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
4936 /* Adjust edges appropriately to connect new head with first head
4937 as well as second head. */
4938 e0
= single_succ_edge (cond_bb
);
4939 e0
->flags
&= ~EDGE_FALLTHRU
;
4940 e0
->flags
|= EDGE_FALSE_VALUE
;
4943 struct cfg_hooks tree_cfg_hooks
= {
4945 tree_verify_flow_info
,
4946 tree_dump_bb
, /* dump_bb */
4947 create_bb
, /* create_basic_block */
4948 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
4949 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
4950 remove_bb
, /* delete_basic_block */
4951 tree_split_block
, /* split_block */
4952 tree_move_block_after
, /* move_block_after */
4953 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
4954 tree_merge_blocks
, /* merge_blocks */
4955 tree_predict_edge
, /* predict_edge */
4956 tree_predicted_by_p
, /* predicted_by_p */
4957 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
4958 tree_duplicate_bb
, /* duplicate_block */
4959 tree_split_edge
, /* split_edge */
4960 tree_make_forwarder_block
, /* make_forward_block */
4961 NULL
, /* tidy_fallthru_edge */
4962 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
4963 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
4964 tree_flow_call_edges_add
, /* flow_call_edges_add */
4965 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
4966 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
4967 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
4968 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
4969 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
4970 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
4971 flush_pending_stmts
/* flush_pending_stmts */
4975 /* Split all critical edges. */
4978 split_critical_edges (void)
4984 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
4985 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
4986 mappings around the calls to split_edge. */
4987 start_recording_case_labels ();
4990 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4991 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
4996 end_recording_case_labels ();
4999 struct tree_opt_pass pass_split_crit_edges
=
5001 "crited", /* name */
5003 split_critical_edges
, /* execute */
5006 0, /* static_pass_number */
5007 TV_TREE_SPLIT_EDGES
, /* tv_id */
5008 PROP_cfg
, /* properties required */
5009 PROP_no_crit_edges
, /* properties_provided */
5010 0, /* properties_destroyed */
5011 0, /* todo_flags_start */
5012 TODO_dump_func
, /* todo_flags_finish */
5017 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5018 a temporary, make sure and register it to be renamed if necessary,
5019 and finally return the temporary. Put the statements to compute
5020 EXP before the current statement in BSI. */
5023 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5025 tree t
, new_stmt
, orig_stmt
;
5027 if (is_gimple_val (exp
))
5030 t
= make_rename_temp (type
, NULL
);
5031 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5033 orig_stmt
= bsi_stmt (*bsi
);
5034 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5035 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5037 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5042 /* Build a ternary operation and gimplify it. Emit code before BSI.
5043 Return the gimple_val holding the result. */
5046 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5047 tree type
, tree a
, tree b
, tree c
)
5051 ret
= fold_build3 (code
, type
, a
, b
, c
);
5054 return gimplify_val (bsi
, type
, ret
);
5057 /* Build a binary operation and gimplify it. Emit code before BSI.
5058 Return the gimple_val holding the result. */
5061 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5062 tree type
, tree a
, tree b
)
5066 ret
= fold_build2 (code
, type
, a
, b
);
5069 return gimplify_val (bsi
, type
, ret
);
5072 /* Build a unary operation and gimplify it. Emit code before BSI.
5073 Return the gimple_val holding the result. */
5076 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5081 ret
= fold_build1 (code
, type
, a
);
5084 return gimplify_val (bsi
, type
, ret
);
5089 /* Emit return warnings. */
5092 execute_warn_function_return (void)
5094 #ifdef USE_MAPPED_LOCATION
5095 source_location location
;
5103 /* If we have a path to EXIT, then we do return. */
5104 if (TREE_THIS_VOLATILE (cfun
->decl
)
5105 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5107 #ifdef USE_MAPPED_LOCATION
5108 location
= UNKNOWN_LOCATION
;
5112 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5114 last
= last_stmt (e
->src
);
5115 if (TREE_CODE (last
) == RETURN_EXPR
5116 #ifdef USE_MAPPED_LOCATION
5117 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5119 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5123 #ifdef USE_MAPPED_LOCATION
5124 if (location
== UNKNOWN_LOCATION
)
5125 location
= cfun
->function_end_locus
;
5126 warning (0, "%H%<noreturn%> function does return", &location
);
5129 locus
= &cfun
->function_end_locus
;
5130 warning (0, "%H%<noreturn%> function does return", locus
);
5134 /* If we see "return;" in some basic block, then we do reach the end
5135 without returning a value. */
5136 else if (warn_return_type
5137 && !TREE_NO_WARNING (cfun
->decl
)
5138 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5139 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5141 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5143 tree last
= last_stmt (e
->src
);
5144 if (TREE_CODE (last
) == RETURN_EXPR
5145 && TREE_OPERAND (last
, 0) == NULL
5146 && !TREE_NO_WARNING (last
))
5148 #ifdef USE_MAPPED_LOCATION
5149 location
= EXPR_LOCATION (last
);
5150 if (location
== UNKNOWN_LOCATION
)
5151 location
= cfun
->function_end_locus
;
5152 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5154 locus
= EXPR_LOCUS (last
);
5156 locus
= &cfun
->function_end_locus
;
5157 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5159 TREE_NO_WARNING (cfun
->decl
) = 1;
5167 /* Given a basic block B which ends with a conditional and has
5168 precisely two successors, determine which of the edges is taken if
5169 the conditional is true and which is taken if the conditional is
5170 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5173 extract_true_false_edges_from_block (basic_block b
,
5177 edge e
= EDGE_SUCC (b
, 0);
5179 if (e
->flags
& EDGE_TRUE_VALUE
)
5182 *false_edge
= EDGE_SUCC (b
, 1);
5187 *true_edge
= EDGE_SUCC (b
, 1);
5191 struct tree_opt_pass pass_warn_function_return
=
5195 execute_warn_function_return
, /* execute */
5198 0, /* static_pass_number */
5200 PROP_cfg
, /* properties_required */
5201 0, /* properties_provided */
5202 0, /* properties_destroyed */
5203 0, /* todo_flags_start */
5204 0, /* todo_flags_finish */
5208 /* Emit noreturn warnings. */
5211 execute_warn_function_noreturn (void)
5213 if (warn_missing_noreturn
5214 && !TREE_THIS_VOLATILE (cfun
->decl
)
5215 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5216 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5217 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5218 "for attribute %<noreturn%>",
5222 struct tree_opt_pass pass_warn_function_noreturn
=
5226 execute_warn_function_noreturn
, /* execute */
5229 0, /* static_pass_number */
5231 PROP_cfg
, /* properties_required */
5232 0, /* properties_provided */
5233 0, /* properties_destroyed */
5234 0, /* todo_flags_start */
5235 0, /* todo_flags_finish */