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 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
138 VEC_safe_grow (basic_block
, gc
, label_to_block_map
, initial_cfg_capacity
);
139 memset (VEC_address (basic_block
, label_to_block_map
),
140 0, sizeof (basic_block
) * initial_cfg_capacity
);
142 BASIC_BLOCK (ENTRY_BLOCK
) = ENTRY_BLOCK_PTR
;
143 BASIC_BLOCK (EXIT_BLOCK
) = EXIT_BLOCK_PTR
;
144 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
145 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
148 /*---------------------------------------------------------------------------
150 ---------------------------------------------------------------------------*/
152 /* Entry point to the CFG builder for trees. TP points to the list of
153 statements to be added to the flowgraph. */
156 build_tree_cfg (tree
*tp
)
158 /* Register specific tree functions. */
159 tree_register_cfg_hooks ();
161 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
163 init_empty_tree_cfg ();
165 found_computed_goto
= 0;
168 /* Computed gotos are hell to deal with, especially if there are
169 lots of them with a large number of destinations. So we factor
170 them to a common computed goto location before we build the
171 edge list. After we convert back to normal form, we will un-factor
172 the computed gotos since factoring introduces an unwanted jump. */
173 if (found_computed_goto
)
174 factor_computed_gotos ();
176 /* Make sure there is always at least one block, even if it's empty. */
177 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
178 create_empty_bb (ENTRY_BLOCK_PTR
);
180 /* Adjust the size of the array. */
181 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
183 /* To speed up statement iterator walks, we first purge dead labels. */
184 cleanup_dead_labels ();
186 /* Group case nodes to reduce the number of edges.
187 We do this after cleaning up dead labels because otherwise we miss
188 a lot of obvious case merging opportunities. */
189 group_case_labels ();
191 /* Create the edges of the flowgraph. */
194 /* Debugging dumps. */
196 /* Write the flowgraph to a VCG file. */
198 int local_dump_flags
;
199 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
202 tree_cfg2vcg (dump_file
);
203 dump_end (TDI_vcg
, dump_file
);
207 #ifdef ENABLE_CHECKING
211 /* Dump a textual representation of the flowgraph. */
213 dump_tree_cfg (dump_file
, dump_flags
);
217 execute_build_cfg (void)
219 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
222 struct tree_opt_pass pass_build_cfg
=
226 execute_build_cfg
, /* execute */
229 0, /* static_pass_number */
230 TV_TREE_CFG
, /* tv_id */
231 PROP_gimple_leh
, /* properties_required */
232 PROP_cfg
, /* properties_provided */
233 0, /* properties_destroyed */
234 0, /* todo_flags_start */
235 TODO_verify_stmts
, /* todo_flags_finish */
239 /* Search the CFG for any computed gotos. If found, factor them to a
240 common computed goto site. Also record the location of that site so
241 that we can un-factor the gotos after we have converted back to
245 factor_computed_gotos (void)
248 tree factored_label_decl
= NULL
;
250 tree factored_computed_goto_label
= NULL
;
251 tree factored_computed_goto
= NULL
;
253 /* We know there are one or more computed gotos in this function.
254 Examine the last statement in each basic block to see if the block
255 ends with a computed goto. */
259 block_stmt_iterator bsi
= bsi_last (bb
);
264 last
= bsi_stmt (bsi
);
266 /* Ignore the computed goto we create when we factor the original
268 if (last
== factored_computed_goto
)
271 /* If the last statement is a computed goto, factor it. */
272 if (computed_goto_p (last
))
276 /* The first time we find a computed goto we need to create
277 the factored goto block and the variable each original
278 computed goto will use for their goto destination. */
279 if (! factored_computed_goto
)
281 basic_block new_bb
= create_empty_bb (bb
);
282 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
284 /* Create the destination of the factored goto. Each original
285 computed goto will put its desired destination into this
286 variable and jump to the label we create immediately
288 var
= create_tmp_var (ptr_type_node
, "gotovar");
290 /* Build a label for the new block which will contain the
291 factored computed goto. */
292 factored_label_decl
= create_artificial_label ();
293 factored_computed_goto_label
294 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
295 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
298 /* Build our new computed goto. */
299 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
300 bsi_insert_after (&new_bsi
, factored_computed_goto
,
304 /* Copy the original computed goto's destination into VAR. */
305 assignment
= build2 (MODIFY_EXPR
, ptr_type_node
,
306 var
, GOTO_DESTINATION (last
));
307 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
309 /* And re-vector the computed goto to the new destination. */
310 GOTO_DESTINATION (last
) = factored_label_decl
;
316 /* Build a flowgraph for the statement_list STMT_LIST. */
319 make_blocks (tree stmt_list
)
321 tree_stmt_iterator i
= tsi_start (stmt_list
);
323 bool start_new_block
= true;
324 bool first_stmt_of_list
= true;
325 basic_block bb
= ENTRY_BLOCK_PTR
;
327 while (!tsi_end_p (i
))
334 /* If the statement starts a new basic block or if we have determined
335 in a previous pass that we need to create a new block for STMT, do
337 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
339 if (!first_stmt_of_list
)
340 stmt_list
= tsi_split_statement_list_before (&i
);
341 bb
= create_basic_block (stmt_list
, NULL
, bb
);
342 start_new_block
= false;
345 /* Now add STMT to BB and create the subgraphs for special statement
347 set_bb_for_stmt (stmt
, bb
);
349 if (computed_goto_p (stmt
))
350 found_computed_goto
= true;
352 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
354 if (stmt_ends_bb_p (stmt
))
355 start_new_block
= true;
358 first_stmt_of_list
= false;
363 /* Create and return a new empty basic block after bb AFTER. */
366 create_bb (void *h
, void *e
, basic_block after
)
372 /* Create and initialize a new basic block. Since alloc_block uses
373 ggc_alloc_cleared to allocate a basic block, we do not have to
374 clear the newly allocated basic block here. */
377 bb
->index
= last_basic_block
;
379 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
381 /* Add the new block to the linked list of blocks. */
382 link_block (bb
, after
);
384 /* Grow the basic block array if needed. */
385 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
387 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
388 VARRAY_GROW (basic_block_info
, new_size
);
391 /* Add the newly created block to the array. */
392 BASIC_BLOCK (last_basic_block
) = bb
;
401 /*---------------------------------------------------------------------------
403 ---------------------------------------------------------------------------*/
405 /* Fold COND_EXPR_COND of each COND_EXPR. */
408 fold_cond_expr_cond (void)
414 tree stmt
= last_stmt (bb
);
417 && TREE_CODE (stmt
) == COND_EXPR
)
419 tree cond
= fold (COND_EXPR_COND (stmt
));
420 if (integer_zerop (cond
))
421 COND_EXPR_COND (stmt
) = boolean_false_node
;
422 else if (integer_onep (cond
))
423 COND_EXPR_COND (stmt
) = boolean_true_node
;
428 /* Join all the blocks in the flowgraph. */
435 /* Create an edge from entry to the first block with executable
437 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
439 /* Traverse the basic block array placing edges. */
442 tree first
= first_stmt (bb
);
443 tree last
= last_stmt (bb
);
447 /* Edges for statements that always alter flow control. */
448 if (is_ctrl_stmt (last
))
449 make_ctrl_stmt_edges (bb
);
451 /* Edges for statements that sometimes alter flow control. */
452 if (is_ctrl_altering_stmt (last
))
453 make_exit_edges (bb
);
456 /* Finally, if no edges were created above, this is a regular
457 basic block that only needs a fallthru edge. */
458 if (EDGE_COUNT (bb
->succs
) == 0)
459 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
462 /* We do not care about fake edges, so remove any that the CFG
463 builder inserted for completeness. */
464 remove_fake_exit_edges ();
466 /* Fold COND_EXPR_COND of each COND_EXPR. */
467 fold_cond_expr_cond ();
469 /* Clean up the graph and warn for unreachable code. */
474 /* Create edges for control statement at basic block BB. */
477 make_ctrl_stmt_edges (basic_block bb
)
479 tree last
= last_stmt (bb
);
482 switch (TREE_CODE (last
))
485 make_goto_expr_edges (bb
);
489 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
493 make_cond_expr_edges (bb
);
497 make_switch_expr_edges (bb
);
501 make_eh_edges (last
);
502 /* Yet another NORETURN hack. */
503 if (EDGE_COUNT (bb
->succs
) == 0)
504 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
513 /* Create exit edges for statements in block BB that alter the flow of
514 control. Statements that alter the control flow are 'goto', 'return'
515 and calls to non-returning functions. */
518 make_exit_edges (basic_block bb
)
520 tree last
= last_stmt (bb
), op
;
523 switch (TREE_CODE (last
))
528 /* If this function receives a nonlocal goto, then we need to
529 make edges from this call site to all the nonlocal goto
531 if (TREE_SIDE_EFFECTS (last
)
532 && current_function_has_nonlocal_label
)
533 make_goto_expr_edges (bb
);
535 /* If this statement has reachable exception handlers, then
536 create abnormal edges to them. */
537 make_eh_edges (last
);
539 /* Some calls are known not to return. For such calls we create
542 We really need to revamp how we build edges so that it's not
543 such a bloody pain to avoid creating edges for this case since
544 all we do is remove these edges when we're done building the
546 if (call_expr_flags (last
) & ECF_NORETURN
)
548 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
552 /* Don't forget the fall-thru edge. */
553 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
557 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
558 may have an abnormal edge. Search the RHS for this case and
559 create any required edges. */
560 op
= get_call_expr_in (last
);
561 if (op
&& TREE_SIDE_EFFECTS (op
)
562 && current_function_has_nonlocal_label
)
563 make_goto_expr_edges (bb
);
565 make_eh_edges (last
);
566 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
575 /* Create the edges for a COND_EXPR starting at block BB.
576 At this point, both clauses must contain only simple gotos. */
579 make_cond_expr_edges (basic_block bb
)
581 tree entry
= last_stmt (bb
);
582 basic_block then_bb
, else_bb
;
583 tree then_label
, else_label
;
587 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
589 /* Entry basic blocks for each component. */
590 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
591 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
592 then_bb
= label_to_block (then_label
);
593 else_bb
= label_to_block (else_label
);
595 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
596 #ifdef USE_MAPPED_LOCATION
597 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
599 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
601 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
604 #ifdef USE_MAPPED_LOCATION
605 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
607 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
612 /* Hashing routine for EDGE_TO_CASES. */
615 edge_to_cases_hash (const void *p
)
617 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
619 /* Hash on the edge itself (which is a pointer). */
620 return htab_hash_pointer (e
);
623 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
624 for equality is just a pointer comparison. */
627 edge_to_cases_eq (const void *p1
, const void *p2
)
629 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
630 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
635 /* Called for each element in the hash table (P) as we delete the
636 edge to cases hash table.
638 Clear all the TREE_CHAINs to prevent problems with copying of
639 SWITCH_EXPRs and structure sharing rules, then free the hash table
643 edge_to_cases_cleanup (void *p
)
645 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
648 for (t
= elt
->case_labels
; t
; t
= next
)
650 next
= TREE_CHAIN (t
);
651 TREE_CHAIN (t
) = NULL
;
656 /* Start recording information mapping edges to case labels. */
659 start_recording_case_labels (void)
661 gcc_assert (edge_to_cases
== NULL
);
663 edge_to_cases
= htab_create (37,
666 edge_to_cases_cleanup
);
669 /* Return nonzero if we are recording information for case labels. */
672 recording_case_labels_p (void)
674 return (edge_to_cases
!= NULL
);
677 /* Stop recording information mapping edges to case labels and
678 remove any information we have recorded. */
680 end_recording_case_labels (void)
682 htab_delete (edge_to_cases
);
683 edge_to_cases
= NULL
;
686 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
689 record_switch_edge (edge e
, tree case_label
)
691 struct edge_to_cases_elt
*elt
;
694 /* Build a hash table element so we can see if E is already
696 elt
= XNEW (struct edge_to_cases_elt
);
698 elt
->case_labels
= case_label
;
700 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
704 /* E was not in the hash table. Install E into the hash table. */
709 /* E was already in the hash table. Free ELT as we do not need it
713 /* Get the entry stored in the hash table. */
714 elt
= (struct edge_to_cases_elt
*) *slot
;
716 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
717 TREE_CHAIN (case_label
) = elt
->case_labels
;
718 elt
->case_labels
= case_label
;
722 /* If we are inside a {start,end}_recording_cases block, then return
723 a chain of CASE_LABEL_EXPRs from T which reference E.
725 Otherwise return NULL. */
728 get_cases_for_edge (edge e
, tree t
)
730 struct edge_to_cases_elt elt
, *elt_p
;
735 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
736 chains available. Return NULL so the caller can detect this case. */
737 if (!recording_case_labels_p ())
742 elt
.case_labels
= NULL
;
743 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
747 elt_p
= (struct edge_to_cases_elt
*)*slot
;
748 return elt_p
->case_labels
;
751 /* If we did not find E in the hash table, then this must be the first
752 time we have been queried for information about E & T. Add all the
753 elements from T to the hash table then perform the query again. */
755 vec
= SWITCH_LABELS (t
);
756 n
= TREE_VEC_LENGTH (vec
);
757 for (i
= 0; i
< n
; i
++)
759 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
760 basic_block label_bb
= label_to_block (lab
);
761 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
766 /* Create the edges for a SWITCH_EXPR starting at block BB.
767 At this point, the switch body has been lowered and the
768 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
771 make_switch_expr_edges (basic_block bb
)
773 tree entry
= last_stmt (bb
);
777 vec
= SWITCH_LABELS (entry
);
778 n
= TREE_VEC_LENGTH (vec
);
780 for (i
= 0; i
< n
; ++i
)
782 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
783 basic_block label_bb
= label_to_block (lab
);
784 make_edge (bb
, label_bb
, 0);
789 /* Return the basic block holding label DEST. */
792 label_to_block_fn (struct function
*ifun
, tree dest
)
794 int uid
= LABEL_DECL_UID (dest
);
796 /* We would die hard when faced by an undefined label. Emit a label to
797 the very first basic block. This will hopefully make even the dataflow
798 and undefined variable warnings quite right. */
799 if ((errorcount
|| sorrycount
) && uid
< 0)
801 block_stmt_iterator bsi
=
802 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
805 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
806 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
807 uid
= LABEL_DECL_UID (dest
);
809 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
810 <= (unsigned int) uid
)
812 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
815 /* Create edges for a goto statement at block BB. */
818 make_goto_expr_edges (basic_block bb
)
821 basic_block target_bb
;
823 block_stmt_iterator last
= bsi_last (bb
);
825 goto_t
= bsi_stmt (last
);
827 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
828 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
829 from a nonlocal goto. */
830 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
834 tree dest
= GOTO_DESTINATION (goto_t
);
837 /* A GOTO to a local label creates normal edges. */
838 if (simple_goto_p (goto_t
))
840 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
841 #ifdef USE_MAPPED_LOCATION
842 e
->goto_locus
= EXPR_LOCATION (goto_t
);
844 e
->goto_locus
= EXPR_LOCUS (goto_t
);
850 /* Nothing more to do for nonlocal gotos. */
851 if (TREE_CODE (dest
) == LABEL_DECL
)
854 /* Computed gotos remain. */
857 /* Look for the block starting with the destination label. In the
858 case of a computed goto, make an edge to any label block we find
860 FOR_EACH_BB (target_bb
)
862 block_stmt_iterator bsi
;
864 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
866 tree target
= bsi_stmt (bsi
);
868 if (TREE_CODE (target
) != LABEL_EXPR
)
872 /* Computed GOTOs. Make an edge to every label block that has
873 been marked as a potential target for a computed goto. */
874 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
875 /* Nonlocal GOTO target. Make an edge to every label block
876 that has been marked as a potential target for a nonlocal
878 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
880 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
886 /* Degenerate case of computed goto with no labels. */
887 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
888 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
892 /*---------------------------------------------------------------------------
894 ---------------------------------------------------------------------------*/
896 /* Cleanup useless labels in basic blocks. This is something we wish
897 to do early because it allows us to group case labels before creating
898 the edges for the CFG, and it speeds up block statement iterators in
900 We only run this pass once, running it more than once is probably not
903 /* A map from basic block index to the leading label of that block. */
904 static tree
*label_for_bb
;
906 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
908 update_eh_label (struct eh_region
*region
)
910 tree old_label
= get_eh_region_tree_label (region
);
914 basic_block bb
= label_to_block (old_label
);
916 /* ??? After optimizing, there may be EH regions with labels
917 that have already been removed from the function body, so
918 there is no basic block for them. */
922 new_label
= label_for_bb
[bb
->index
];
923 set_eh_region_tree_label (region
, new_label
);
927 /* Given LABEL return the first label in the same basic block. */
929 main_block_label (tree label
)
931 basic_block bb
= label_to_block (label
);
933 /* label_to_block possibly inserted undefined label into the chain. */
934 if (!label_for_bb
[bb
->index
])
935 label_for_bb
[bb
->index
] = label
;
936 return label_for_bb
[bb
->index
];
939 /* Cleanup redundant labels. This is a three-step process:
940 1) Find the leading label for each block.
941 2) Redirect all references to labels to the leading labels.
942 3) Cleanup all useless labels. */
945 cleanup_dead_labels (void)
948 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
950 /* Find a suitable label for each block. We use the first user-defined
951 label if there is one, or otherwise just the first label we see. */
954 block_stmt_iterator i
;
956 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
958 tree label
, stmt
= bsi_stmt (i
);
960 if (TREE_CODE (stmt
) != LABEL_EXPR
)
963 label
= LABEL_EXPR_LABEL (stmt
);
965 /* If we have not yet seen a label for the current block,
966 remember this one and see if there are more labels. */
967 if (! label_for_bb
[bb
->index
])
969 label_for_bb
[bb
->index
] = label
;
973 /* If we did see a label for the current block already, but it
974 is an artificially created label, replace it if the current
975 label is a user defined label. */
976 if (! DECL_ARTIFICIAL (label
)
977 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
979 label_for_bb
[bb
->index
] = label
;
985 /* Now redirect all jumps/branches to the selected label.
986 First do so for each block ending in a control statement. */
989 tree stmt
= last_stmt (bb
);
993 switch (TREE_CODE (stmt
))
997 tree true_branch
, false_branch
;
999 true_branch
= COND_EXPR_THEN (stmt
);
1000 false_branch
= COND_EXPR_ELSE (stmt
);
1002 GOTO_DESTINATION (true_branch
)
1003 = main_block_label (GOTO_DESTINATION (true_branch
));
1004 GOTO_DESTINATION (false_branch
)
1005 = main_block_label (GOTO_DESTINATION (false_branch
));
1013 tree vec
= SWITCH_LABELS (stmt
);
1014 size_t n
= TREE_VEC_LENGTH (vec
);
1016 /* Replace all destination labels. */
1017 for (i
= 0; i
< n
; ++i
)
1019 tree elt
= TREE_VEC_ELT (vec
, i
);
1020 tree label
= main_block_label (CASE_LABEL (elt
));
1021 CASE_LABEL (elt
) = label
;
1026 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1027 remove them until after we've created the CFG edges. */
1029 if (! computed_goto_p (stmt
))
1031 GOTO_DESTINATION (stmt
)
1032 = main_block_label (GOTO_DESTINATION (stmt
));
1041 for_each_eh_region (update_eh_label
);
1043 /* Finally, purge dead labels. All user-defined labels and labels that
1044 can be the target of non-local gotos are preserved. */
1047 block_stmt_iterator i
;
1048 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1050 if (! label_for_this_bb
)
1053 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1055 tree label
, stmt
= bsi_stmt (i
);
1057 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1060 label
= LABEL_EXPR_LABEL (stmt
);
1062 if (label
== label_for_this_bb
1063 || ! DECL_ARTIFICIAL (label
)
1064 || DECL_NONLOCAL (label
))
1071 free (label_for_bb
);
1074 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1075 and scan the sorted vector of cases. Combine the ones jumping to the
1077 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1080 group_case_labels (void)
1086 tree stmt
= last_stmt (bb
);
1087 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1089 tree labels
= SWITCH_LABELS (stmt
);
1090 int old_size
= TREE_VEC_LENGTH (labels
);
1091 int i
, j
, new_size
= old_size
;
1092 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1095 /* The default label is always the last case in a switch
1096 statement after gimplification. */
1097 default_label
= CASE_LABEL (default_case
);
1099 /* Look for possible opportunities to merge cases.
1100 Ignore the last element of the label vector because it
1101 must be the default case. */
1103 while (i
< old_size
- 1)
1105 tree base_case
, base_label
, base_high
;
1106 base_case
= TREE_VEC_ELT (labels
, i
);
1108 gcc_assert (base_case
);
1109 base_label
= CASE_LABEL (base_case
);
1111 /* Discard cases that have the same destination as the
1113 if (base_label
== default_label
)
1115 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1121 base_high
= CASE_HIGH (base_case
) ?
1122 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1124 /* Try to merge case labels. Break out when we reach the end
1125 of the label vector or when we cannot merge the next case
1126 label with the current one. */
1127 while (i
< old_size
- 1)
1129 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1130 tree merge_label
= CASE_LABEL (merge_case
);
1131 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1132 integer_one_node
, 1);
1134 /* Merge the cases if they jump to the same place,
1135 and their ranges are consecutive. */
1136 if (merge_label
== base_label
1137 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1139 base_high
= CASE_HIGH (merge_case
) ?
1140 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1141 CASE_HIGH (base_case
) = base_high
;
1142 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1151 /* Compress the case labels in the label vector, and adjust the
1152 length of the vector. */
1153 for (i
= 0, j
= 0; i
< new_size
; i
++)
1155 while (! TREE_VEC_ELT (labels
, j
))
1157 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1159 TREE_VEC_LENGTH (labels
) = new_size
;
1164 /* Checks whether we can merge block B into block A. */
1167 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1170 block_stmt_iterator bsi
;
1173 if (!single_succ_p (a
))
1176 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1179 if (single_succ (a
) != b
)
1182 if (!single_pred_p (b
))
1185 if (b
== EXIT_BLOCK_PTR
)
1188 /* If A ends by a statement causing exceptions or something similar, we
1189 cannot merge the blocks. */
1190 stmt
= last_stmt (a
);
1191 if (stmt
&& stmt_ends_bb_p (stmt
))
1194 /* Do not allow a block with only a non-local label to be merged. */
1195 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1196 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1199 /* It must be possible to eliminate all phi nodes in B. If ssa form
1200 is not up-to-date, we cannot eliminate any phis. */
1201 phi
= phi_nodes (b
);
1204 if (need_ssa_update_p ())
1207 for (; phi
; phi
= PHI_CHAIN (phi
))
1208 if (!is_gimple_reg (PHI_RESULT (phi
))
1209 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1213 /* Do not remove user labels. */
1214 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1216 stmt
= bsi_stmt (bsi
);
1217 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1219 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1223 /* Protect the loop latches. */
1225 && b
->loop_father
->latch
== b
)
1231 /* Replaces all uses of NAME by VAL. */
1234 replace_uses_by (tree name
, tree val
)
1236 imm_use_iterator imm_iter
;
1241 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1243 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1245 stmt
= USE_STMT (use
);
1246 replace_exp (use
, val
);
1248 if (TREE_CODE (stmt
) == PHI_NODE
)
1250 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1251 if (e
->flags
& EDGE_ABNORMAL
)
1253 /* This can only occur for virtual operands, since
1254 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1255 would prevent replacement. */
1256 gcc_assert (!is_gimple_reg (name
));
1257 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1261 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1264 /* We do not update the statements in the loop above. Consider
1267 If we performed the update in the first loop, the statement
1268 would be rescanned after first occurrence of w is replaced,
1269 the new uses would be placed to the beginning of the list,
1270 and we would never process them. */
1271 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1275 fold_stmt_inplace (stmt
);
1277 rhs
= get_rhs (stmt
);
1278 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1279 recompute_tree_invariant_for_addr_expr (rhs
);
1281 /* If the statement could throw and now cannot, we need to prune cfg. */
1282 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
1283 tree_purge_dead_eh_edges (bb_for_stmt (stmt
));
1285 mark_new_vars_to_rename (stmt
);
1288 VEC_free (tree
, heap
, stmts
);
1290 /* Also update the trees stored in loop structures. */
1295 for (i
= 0; i
< current_loops
->num
; i
++)
1297 loop
= current_loops
->parray
[i
];
1299 substitute_in_loop_info (loop
, name
, val
);
1304 /* Merge block B into block A. */
1307 tree_merge_blocks (basic_block a
, basic_block b
)
1309 block_stmt_iterator bsi
;
1310 tree_stmt_iterator last
;
1314 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1316 /* Remove all single-valued PHI nodes from block B of the form
1317 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1319 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1321 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1323 bool may_replace_uses
= may_propagate_copy (def
, use
);
1325 /* In case we have loops to care about, do not propagate arguments of
1326 loop closed ssa phi nodes. */
1328 && is_gimple_reg (def
)
1329 && TREE_CODE (use
) == SSA_NAME
1330 && a
->loop_father
!= b
->loop_father
)
1331 may_replace_uses
= false;
1333 if (!may_replace_uses
)
1335 gcc_assert (is_gimple_reg (def
));
1337 /* Note that just emitting the copies is fine -- there is no problem
1338 with ordering of phi nodes. This is because A is the single
1339 predecessor of B, therefore results of the phi nodes cannot
1340 appear as arguments of the phi nodes. */
1341 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1342 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1343 SET_PHI_RESULT (phi
, NULL_TREE
);
1344 SSA_NAME_DEF_STMT (def
) = copy
;
1347 replace_uses_by (def
, use
);
1349 remove_phi_node (phi
, NULL
);
1352 /* Ensure that B follows A. */
1353 move_block_after (b
, a
);
1355 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1356 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1358 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1359 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1361 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1363 tree label
= bsi_stmt (bsi
);
1366 /* Now that we can thread computed gotos, we might have
1367 a situation where we have a forced label in block B
1368 However, the label at the start of block B might still be
1369 used in other ways (think about the runtime checking for
1370 Fortran assigned gotos). So we can not just delete the
1371 label. Instead we move the label to the start of block A. */
1372 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1374 block_stmt_iterator dest_bsi
= bsi_start (a
);
1375 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1380 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1385 /* Merge the chains. */
1386 last
= tsi_last (a
->stmt_list
);
1387 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1388 b
->stmt_list
= NULL
;
1392 /* Walk the function tree removing unnecessary statements.
1394 * Empty statement nodes are removed
1396 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1398 * Unnecessary COND_EXPRs are removed
1400 * Some unnecessary BIND_EXPRs are removed
1402 Clearly more work could be done. The trick is doing the analysis
1403 and removal fast enough to be a net improvement in compile times.
1405 Note that when we remove a control structure such as a COND_EXPR
1406 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1407 to ensure we eliminate all the useless code. */
1418 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1421 remove_useless_stmts_warn_notreached (tree stmt
)
1423 if (EXPR_HAS_LOCATION (stmt
))
1425 location_t loc
= EXPR_LOCATION (stmt
);
1426 if (LOCATION_LINE (loc
) > 0)
1428 warning (0, "%Hwill never be executed", &loc
);
1433 switch (TREE_CODE (stmt
))
1435 case STATEMENT_LIST
:
1437 tree_stmt_iterator i
;
1438 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1439 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1445 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1447 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1449 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1453 case TRY_FINALLY_EXPR
:
1454 case TRY_CATCH_EXPR
:
1455 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1457 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1462 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1463 case EH_FILTER_EXPR
:
1464 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1466 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1469 /* Not a live container. */
1477 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1479 tree then_clause
, else_clause
, cond
;
1480 bool save_has_label
, then_has_label
, else_has_label
;
1482 save_has_label
= data
->has_label
;
1483 data
->has_label
= false;
1484 data
->last_goto
= NULL
;
1486 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1488 then_has_label
= data
->has_label
;
1489 data
->has_label
= false;
1490 data
->last_goto
= NULL
;
1492 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1494 else_has_label
= data
->has_label
;
1495 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1497 then_clause
= COND_EXPR_THEN (*stmt_p
);
1498 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1499 cond
= fold (COND_EXPR_COND (*stmt_p
));
1501 /* If neither arm does anything at all, we can remove the whole IF. */
1502 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1504 *stmt_p
= build_empty_stmt ();
1505 data
->repeat
= true;
1508 /* If there are no reachable statements in an arm, then we can
1509 zap the entire conditional. */
1510 else if (integer_nonzerop (cond
) && !else_has_label
)
1512 if (warn_notreached
)
1513 remove_useless_stmts_warn_notreached (else_clause
);
1514 *stmt_p
= then_clause
;
1515 data
->repeat
= true;
1517 else if (integer_zerop (cond
) && !then_has_label
)
1519 if (warn_notreached
)
1520 remove_useless_stmts_warn_notreached (then_clause
);
1521 *stmt_p
= else_clause
;
1522 data
->repeat
= true;
1525 /* Check a couple of simple things on then/else with single stmts. */
1528 tree then_stmt
= expr_only (then_clause
);
1529 tree else_stmt
= expr_only (else_clause
);
1531 /* Notice branches to a common destination. */
1532 if (then_stmt
&& else_stmt
1533 && TREE_CODE (then_stmt
) == GOTO_EXPR
1534 && TREE_CODE (else_stmt
) == GOTO_EXPR
1535 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1537 *stmt_p
= then_stmt
;
1538 data
->repeat
= true;
1541 /* If the THEN/ELSE clause merely assigns a value to a variable or
1542 parameter which is already known to contain that value, then
1543 remove the useless THEN/ELSE clause. */
1544 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1547 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1548 && TREE_OPERAND (else_stmt
, 0) == cond
1549 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1550 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1552 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1553 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1554 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1555 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1557 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1558 ? then_stmt
: else_stmt
);
1559 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1560 ? &COND_EXPR_THEN (*stmt_p
)
1561 : &COND_EXPR_ELSE (*stmt_p
));
1564 && TREE_CODE (stmt
) == MODIFY_EXPR
1565 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1566 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1567 *location
= alloc_stmt_list ();
1571 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1572 would be re-introduced during lowering. */
1573 data
->last_goto
= NULL
;
1578 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1580 bool save_may_branch
, save_may_throw
;
1581 bool this_may_branch
, this_may_throw
;
1583 /* Collect may_branch and may_throw information for the body only. */
1584 save_may_branch
= data
->may_branch
;
1585 save_may_throw
= data
->may_throw
;
1586 data
->may_branch
= false;
1587 data
->may_throw
= false;
1588 data
->last_goto
= NULL
;
1590 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1592 this_may_branch
= data
->may_branch
;
1593 this_may_throw
= data
->may_throw
;
1594 data
->may_branch
|= save_may_branch
;
1595 data
->may_throw
|= save_may_throw
;
1596 data
->last_goto
= NULL
;
1598 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1600 /* If the body is empty, then we can emit the FINALLY block without
1601 the enclosing TRY_FINALLY_EXPR. */
1602 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1604 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1605 data
->repeat
= true;
1608 /* If the handler is empty, then we can emit the TRY block without
1609 the enclosing TRY_FINALLY_EXPR. */
1610 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1612 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1613 data
->repeat
= true;
1616 /* If the body neither throws, nor branches, then we can safely
1617 string the TRY and FINALLY blocks together. */
1618 else if (!this_may_branch
&& !this_may_throw
)
1620 tree stmt
= *stmt_p
;
1621 *stmt_p
= TREE_OPERAND (stmt
, 0);
1622 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1623 data
->repeat
= true;
1629 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1631 bool save_may_throw
, this_may_throw
;
1632 tree_stmt_iterator i
;
1635 /* Collect may_throw information for the body only. */
1636 save_may_throw
= data
->may_throw
;
1637 data
->may_throw
= false;
1638 data
->last_goto
= NULL
;
1640 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1642 this_may_throw
= data
->may_throw
;
1643 data
->may_throw
= save_may_throw
;
1645 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1646 if (!this_may_throw
)
1648 if (warn_notreached
)
1649 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1650 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1651 data
->repeat
= true;
1655 /* Process the catch clause specially. We may be able to tell that
1656 no exceptions propagate past this point. */
1658 this_may_throw
= true;
1659 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1660 stmt
= tsi_stmt (i
);
1661 data
->last_goto
= NULL
;
1663 switch (TREE_CODE (stmt
))
1666 for (; !tsi_end_p (i
); tsi_next (&i
))
1668 stmt
= tsi_stmt (i
);
1669 /* If we catch all exceptions, then the body does not
1670 propagate exceptions past this point. */
1671 if (CATCH_TYPES (stmt
) == NULL
)
1672 this_may_throw
= false;
1673 data
->last_goto
= NULL
;
1674 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1678 case EH_FILTER_EXPR
:
1679 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1680 this_may_throw
= false;
1681 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1682 this_may_throw
= false;
1683 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1687 /* Otherwise this is a cleanup. */
1688 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1690 /* If the cleanup is empty, then we can emit the TRY block without
1691 the enclosing TRY_CATCH_EXPR. */
1692 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1694 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1695 data
->repeat
= true;
1699 data
->may_throw
|= this_may_throw
;
1704 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1708 /* First remove anything underneath the BIND_EXPR. */
1709 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1711 /* If the BIND_EXPR has no variables, then we can pull everything
1712 up one level and remove the BIND_EXPR, unless this is the toplevel
1713 BIND_EXPR for the current function or an inlined function.
1715 When this situation occurs we will want to apply this
1716 optimization again. */
1717 block
= BIND_EXPR_BLOCK (*stmt_p
);
1718 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1719 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1721 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1722 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1725 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1726 data
->repeat
= true;
1732 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1734 tree dest
= GOTO_DESTINATION (*stmt_p
);
1736 data
->may_branch
= true;
1737 data
->last_goto
= NULL
;
1739 /* Record the last goto expr, so that we can delete it if unnecessary. */
1740 if (TREE_CODE (dest
) == LABEL_DECL
)
1741 data
->last_goto
= stmt_p
;
1746 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1748 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1750 data
->has_label
= true;
1752 /* We do want to jump across non-local label receiver code. */
1753 if (DECL_NONLOCAL (label
))
1754 data
->last_goto
= NULL
;
1756 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1758 *data
->last_goto
= build_empty_stmt ();
1759 data
->repeat
= true;
1762 /* ??? Add something here to delete unused labels. */
1766 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1767 decl. This allows us to eliminate redundant or useless
1768 calls to "const" functions.
1770 Gimplifier already does the same operation, but we may notice functions
1771 being const and pure once their calls has been gimplified, so we need
1772 to update the flag. */
1775 update_call_expr_flags (tree call
)
1777 tree decl
= get_callee_fndecl (call
);
1780 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1781 TREE_SIDE_EFFECTS (call
) = 0;
1782 if (TREE_NOTHROW (decl
))
1783 TREE_NOTHROW (call
) = 1;
1787 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1790 notice_special_calls (tree t
)
1792 int flags
= call_expr_flags (t
);
1794 if (flags
& ECF_MAY_BE_ALLOCA
)
1795 current_function_calls_alloca
= true;
1796 if (flags
& ECF_RETURNS_TWICE
)
1797 current_function_calls_setjmp
= true;
1801 /* Clear flags set by notice_special_calls. Used by dead code removal
1802 to update the flags. */
1805 clear_special_calls (void)
1807 current_function_calls_alloca
= false;
1808 current_function_calls_setjmp
= false;
1813 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1817 switch (TREE_CODE (t
))
1820 remove_useless_stmts_cond (tp
, data
);
1823 case TRY_FINALLY_EXPR
:
1824 remove_useless_stmts_tf (tp
, data
);
1827 case TRY_CATCH_EXPR
:
1828 remove_useless_stmts_tc (tp
, data
);
1832 remove_useless_stmts_bind (tp
, data
);
1836 remove_useless_stmts_goto (tp
, data
);
1840 remove_useless_stmts_label (tp
, data
);
1845 data
->last_goto
= NULL
;
1846 data
->may_branch
= true;
1851 data
->last_goto
= NULL
;
1852 notice_special_calls (t
);
1853 update_call_expr_flags (t
);
1854 if (tree_could_throw_p (t
))
1855 data
->may_throw
= true;
1859 data
->last_goto
= NULL
;
1861 op
= get_call_expr_in (t
);
1864 update_call_expr_flags (op
);
1865 notice_special_calls (op
);
1867 if (tree_could_throw_p (t
))
1868 data
->may_throw
= true;
1871 case STATEMENT_LIST
:
1873 tree_stmt_iterator i
= tsi_start (t
);
1874 while (!tsi_end_p (i
))
1877 if (IS_EMPTY_STMT (t
))
1883 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1886 if (TREE_CODE (t
) == STATEMENT_LIST
)
1888 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1898 data
->last_goto
= NULL
;
1902 data
->last_goto
= NULL
;
1908 remove_useless_stmts (void)
1910 struct rus_data data
;
1912 clear_special_calls ();
1916 memset (&data
, 0, sizeof (data
));
1917 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1919 while (data
.repeat
);
1923 struct tree_opt_pass pass_remove_useless_stmts
=
1925 "useless", /* name */
1927 remove_useless_stmts
, /* execute */
1930 0, /* static_pass_number */
1932 PROP_gimple_any
, /* properties_required */
1933 0, /* properties_provided */
1934 0, /* properties_destroyed */
1935 0, /* todo_flags_start */
1936 TODO_dump_func
, /* todo_flags_finish */
1940 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1943 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1947 /* Since this block is no longer reachable, we can just delete all
1948 of its PHI nodes. */
1949 phi
= phi_nodes (bb
);
1952 tree next
= PHI_CHAIN (phi
);
1953 remove_phi_node (phi
, NULL_TREE
);
1957 /* Remove edges to BB's successors. */
1958 while (EDGE_COUNT (bb
->succs
) > 0)
1959 remove_edge (EDGE_SUCC (bb
, 0));
1963 /* Remove statements of basic block BB. */
1966 remove_bb (basic_block bb
)
1968 block_stmt_iterator i
;
1969 #ifdef USE_MAPPED_LOCATION
1970 source_location loc
= UNKNOWN_LOCATION
;
1972 source_locus loc
= 0;
1977 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1978 if (dump_flags
& TDF_DETAILS
)
1980 dump_bb (bb
, dump_file
, 0);
1981 fprintf (dump_file
, "\n");
1985 /* If we remove the header or the latch of a loop, mark the loop for
1986 removal by setting its header and latch to NULL. */
1989 struct loop
*loop
= bb
->loop_father
;
1991 if (loop
->latch
== bb
1992 || loop
->header
== bb
)
1995 loop
->header
= NULL
;
1997 /* Also clean up the information associated with the loop. Updating
1998 it would waste time. More importantly, it may refer to ssa
1999 names that were defined in other removed basic block -- these
2000 ssa names are now removed and invalid. */
2001 free_numbers_of_iterations_estimates_loop (loop
);
2005 /* Remove all the instructions in the block. */
2006 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2008 tree stmt
= bsi_stmt (i
);
2009 if (TREE_CODE (stmt
) == LABEL_EXPR
2010 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2011 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2014 block_stmt_iterator new_bsi
;
2016 /* A non-reachable non-local label may still be referenced.
2017 But it no longer needs to carry the extra semantics of
2019 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2021 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2022 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2025 new_bb
= bb
->prev_bb
;
2026 new_bsi
= bsi_start (new_bb
);
2028 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2032 /* Release SSA definitions if we are in SSA. Note that we
2033 may be called when not in SSA. For example,
2034 final_cleanup calls this function via
2035 cleanup_tree_cfg. */
2037 release_defs (stmt
);
2042 /* Don't warn for removed gotos. Gotos are often removed due to
2043 jump threading, thus resulting in bogus warnings. Not great,
2044 since this way we lose warnings for gotos in the original
2045 program that are indeed unreachable. */
2046 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2048 #ifdef USE_MAPPED_LOCATION
2049 if (EXPR_HAS_LOCATION (stmt
))
2050 loc
= EXPR_LOCATION (stmt
);
2053 t
= EXPR_LOCUS (stmt
);
2054 if (t
&& LOCATION_LINE (*t
) > 0)
2060 /* If requested, give a warning that the first statement in the
2061 block is unreachable. We walk statements backwards in the
2062 loop above, so the last statement we process is the first statement
2064 #ifdef USE_MAPPED_LOCATION
2065 if (loc
> BUILTINS_LOCATION
)
2066 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2069 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2072 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2076 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2077 predicate VAL, return the edge that will be taken out of the block.
2078 If VAL does not match a unique edge, NULL is returned. */
2081 find_taken_edge (basic_block bb
, tree val
)
2085 stmt
= last_stmt (bb
);
2088 gcc_assert (is_ctrl_stmt (stmt
));
2091 if (! is_gimple_min_invariant (val
))
2094 if (TREE_CODE (stmt
) == COND_EXPR
)
2095 return find_taken_edge_cond_expr (bb
, val
);
2097 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2098 return find_taken_edge_switch_expr (bb
, val
);
2100 if (computed_goto_p (stmt
))
2101 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2106 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2107 statement, determine which of the outgoing edges will be taken out of the
2108 block. Return NULL if either edge may be taken. */
2111 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2116 dest
= label_to_block (val
);
2119 e
= find_edge (bb
, dest
);
2120 gcc_assert (e
!= NULL
);
2126 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2127 statement, determine which of the two edges will be taken out of the
2128 block. Return NULL if either edge may be taken. */
2131 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2133 edge true_edge
, false_edge
;
2135 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2137 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2138 return (zero_p (val
) ? false_edge
: true_edge
);
2141 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2142 statement, determine which edge will be taken out of the block. Return
2143 NULL if any edge may be taken. */
2146 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2148 tree switch_expr
, taken_case
;
2149 basic_block dest_bb
;
2152 switch_expr
= last_stmt (bb
);
2153 taken_case
= find_case_label_for_value (switch_expr
, val
);
2154 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2156 e
= find_edge (bb
, dest_bb
);
2162 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2163 We can make optimal use here of the fact that the case labels are
2164 sorted: We can do a binary search for a case matching VAL. */
2167 find_case_label_for_value (tree switch_expr
, tree val
)
2169 tree vec
= SWITCH_LABELS (switch_expr
);
2170 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2171 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2173 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2175 size_t i
= (high
+ low
) / 2;
2176 tree t
= TREE_VEC_ELT (vec
, i
);
2179 /* Cache the result of comparing CASE_LOW and val. */
2180 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2187 if (CASE_HIGH (t
) == NULL
)
2189 /* A singe-valued case label. */
2195 /* A case range. We can only handle integer ranges. */
2196 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2201 return default_case
;
2207 /*---------------------------------------------------------------------------
2209 ---------------------------------------------------------------------------*/
2211 /* Dump tree-specific information of block BB to file OUTF. */
2214 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2216 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2220 /* Dump a basic block on stderr. */
2223 debug_tree_bb (basic_block bb
)
2225 dump_bb (bb
, stderr
, 0);
2229 /* Dump basic block with index N on stderr. */
2232 debug_tree_bb_n (int n
)
2234 debug_tree_bb (BASIC_BLOCK (n
));
2235 return BASIC_BLOCK (n
);
2239 /* Dump the CFG on stderr.
2241 FLAGS are the same used by the tree dumping functions
2242 (see TDF_* in tree.h). */
2245 debug_tree_cfg (int flags
)
2247 dump_tree_cfg (stderr
, flags
);
2251 /* Dump the program showing basic block boundaries on the given FILE.
2253 FLAGS are the same used by the tree dumping functions (see TDF_* in
2257 dump_tree_cfg (FILE *file
, int flags
)
2259 if (flags
& TDF_DETAILS
)
2261 const char *funcname
2262 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2265 fprintf (file
, ";; Function %s\n\n", funcname
);
2266 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2267 n_basic_blocks
, n_edges
, last_basic_block
);
2269 brief_dump_cfg (file
);
2270 fprintf (file
, "\n");
2273 if (flags
& TDF_STATS
)
2274 dump_cfg_stats (file
);
2276 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2280 /* Dump CFG statistics on FILE. */
2283 dump_cfg_stats (FILE *file
)
2285 static long max_num_merged_labels
= 0;
2286 unsigned long size
, total
= 0;
2289 const char * const fmt_str
= "%-30s%-13s%12s\n";
2290 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2291 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2292 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2293 const char *funcname
2294 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2297 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2299 fprintf (file
, "---------------------------------------------------------\n");
2300 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2301 fprintf (file
, fmt_str
, "", " instances ", "used ");
2302 fprintf (file
, "---------------------------------------------------------\n");
2304 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2306 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2307 SCALE (size
), LABEL (size
));
2311 num_edges
+= EDGE_COUNT (bb
->succs
);
2312 size
= num_edges
* sizeof (struct edge_def
);
2314 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2316 fprintf (file
, "---------------------------------------------------------\n");
2317 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2319 fprintf (file
, "---------------------------------------------------------\n");
2320 fprintf (file
, "\n");
2322 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2323 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2325 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2326 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2328 fprintf (file
, "\n");
2332 /* Dump CFG statistics on stderr. Keep extern so that it's always
2333 linked in the final executable. */
2336 debug_cfg_stats (void)
2338 dump_cfg_stats (stderr
);
2342 /* Dump the flowgraph to a .vcg FILE. */
2345 tree_cfg2vcg (FILE *file
)
2350 const char *funcname
2351 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2353 /* Write the file header. */
2354 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2355 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2356 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2358 /* Write blocks and edges. */
2359 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2361 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2364 if (e
->flags
& EDGE_FAKE
)
2365 fprintf (file
, " linestyle: dotted priority: 10");
2367 fprintf (file
, " linestyle: solid priority: 100");
2369 fprintf (file
, " }\n");
2375 enum tree_code head_code
, end_code
;
2376 const char *head_name
, *end_name
;
2379 tree first
= first_stmt (bb
);
2380 tree last
= last_stmt (bb
);
2384 head_code
= TREE_CODE (first
);
2385 head_name
= tree_code_name
[head_code
];
2386 head_line
= get_lineno (first
);
2389 head_name
= "no-statement";
2393 end_code
= TREE_CODE (last
);
2394 end_name
= tree_code_name
[end_code
];
2395 end_line
= get_lineno (last
);
2398 end_name
= "no-statement";
2400 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2401 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2404 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2406 if (e
->dest
== EXIT_BLOCK_PTR
)
2407 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2409 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2411 if (e
->flags
& EDGE_FAKE
)
2412 fprintf (file
, " priority: 10 linestyle: dotted");
2414 fprintf (file
, " priority: 100 linestyle: solid");
2416 fprintf (file
, " }\n");
2419 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2423 fputs ("}\n\n", file
);
2428 /*---------------------------------------------------------------------------
2429 Miscellaneous helpers
2430 ---------------------------------------------------------------------------*/
2432 /* Return true if T represents a stmt that always transfers control. */
2435 is_ctrl_stmt (tree t
)
2437 return (TREE_CODE (t
) == COND_EXPR
2438 || TREE_CODE (t
) == SWITCH_EXPR
2439 || TREE_CODE (t
) == GOTO_EXPR
2440 || TREE_CODE (t
) == RETURN_EXPR
2441 || TREE_CODE (t
) == RESX_EXPR
);
2445 /* Return true if T is a statement that may alter the flow of control
2446 (e.g., a call to a non-returning function). */
2449 is_ctrl_altering_stmt (tree t
)
2454 call
= get_call_expr_in (t
);
2457 /* A non-pure/const CALL_EXPR alters flow control if the current
2458 function has nonlocal labels. */
2459 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2462 /* A CALL_EXPR also alters control flow if it does not return. */
2463 if (call_expr_flags (call
) & ECF_NORETURN
)
2467 /* If a statement can throw, it alters control flow. */
2468 return tree_can_throw_internal (t
);
2472 /* Return true if T is a computed goto. */
2475 computed_goto_p (tree t
)
2477 return (TREE_CODE (t
) == GOTO_EXPR
2478 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2482 /* Checks whether EXPR is a simple local goto. */
2485 simple_goto_p (tree expr
)
2487 return (TREE_CODE (expr
) == GOTO_EXPR
2488 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2492 /* Return true if T should start a new basic block. PREV_T is the
2493 statement preceding T. It is used when T is a label or a case label.
2494 Labels should only start a new basic block if their previous statement
2495 wasn't a label. Otherwise, sequence of labels would generate
2496 unnecessary basic blocks that only contain a single label. */
2499 stmt_starts_bb_p (tree t
, tree prev_t
)
2504 /* LABEL_EXPRs start a new basic block only if the preceding
2505 statement wasn't a label of the same type. This prevents the
2506 creation of consecutive blocks that have nothing but a single
2508 if (TREE_CODE (t
) == LABEL_EXPR
)
2510 /* Nonlocal and computed GOTO targets always start a new block. */
2511 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2512 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2515 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2517 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2520 cfg_stats
.num_merged_labels
++;
2531 /* Return true if T should end a basic block. */
2534 stmt_ends_bb_p (tree t
)
2536 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2540 /* Add gotos that used to be represented implicitly in the CFG. */
2543 disband_implicit_edges (void)
2546 block_stmt_iterator last
;
2553 last
= bsi_last (bb
);
2554 stmt
= last_stmt (bb
);
2556 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2558 /* Remove superfluous gotos from COND_EXPR branches. Moved
2559 from cfg_remove_useless_stmts here since it violates the
2560 invariants for tree--cfg correspondence and thus fits better
2561 here where we do it anyway. */
2562 e
= find_edge (bb
, bb
->next_bb
);
2565 if (e
->flags
& EDGE_TRUE_VALUE
)
2566 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2567 else if (e
->flags
& EDGE_FALSE_VALUE
)
2568 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2571 e
->flags
|= EDGE_FALLTHRU
;
2577 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2579 /* Remove the RETURN_EXPR if we may fall though to the exit
2581 gcc_assert (single_succ_p (bb
));
2582 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2584 if (bb
->next_bb
== EXIT_BLOCK_PTR
2585 && !TREE_OPERAND (stmt
, 0))
2588 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2593 /* There can be no fallthru edge if the last statement is a control
2595 if (stmt
&& is_ctrl_stmt (stmt
))
2598 /* Find a fallthru edge and emit the goto if necessary. */
2599 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2600 if (e
->flags
& EDGE_FALLTHRU
)
2603 if (!e
|| e
->dest
== bb
->next_bb
)
2606 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2607 label
= tree_block_label (e
->dest
);
2609 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2610 #ifdef USE_MAPPED_LOCATION
2611 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2613 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2615 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2616 e
->flags
&= ~EDGE_FALLTHRU
;
2620 /* Remove block annotations and other datastructures. */
2623 delete_tree_cfg_annotations (void)
2625 label_to_block_map
= NULL
;
2629 /* Return the first statement in basic block BB. */
2632 first_stmt (basic_block bb
)
2634 block_stmt_iterator i
= bsi_start (bb
);
2635 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2639 /* Return the last statement in basic block BB. */
2642 last_stmt (basic_block bb
)
2644 block_stmt_iterator b
= bsi_last (bb
);
2645 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2649 /* Return a pointer to the last statement in block BB. */
2652 last_stmt_ptr (basic_block bb
)
2654 block_stmt_iterator last
= bsi_last (bb
);
2655 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2659 /* Return the last statement of an otherwise empty block. Return NULL
2660 if the block is totally empty, or if it contains more than one
2664 last_and_only_stmt (basic_block bb
)
2666 block_stmt_iterator i
= bsi_last (bb
);
2672 last
= bsi_stmt (i
);
2677 /* Empty statements should no longer appear in the instruction stream.
2678 Everything that might have appeared before should be deleted by
2679 remove_useless_stmts, and the optimizers should just bsi_remove
2680 instead of smashing with build_empty_stmt.
2682 Thus the only thing that should appear here in a block containing
2683 one executable statement is a label. */
2684 prev
= bsi_stmt (i
);
2685 if (TREE_CODE (prev
) == LABEL_EXPR
)
2692 /* Mark BB as the basic block holding statement T. */
2695 set_bb_for_stmt (tree t
, basic_block bb
)
2697 if (TREE_CODE (t
) == PHI_NODE
)
2699 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2701 tree_stmt_iterator i
;
2702 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2703 set_bb_for_stmt (tsi_stmt (i
), bb
);
2707 stmt_ann_t ann
= get_stmt_ann (t
);
2710 /* If the statement is a label, add the label to block-to-labels map
2711 so that we can speed up edge creation for GOTO_EXPRs. */
2712 if (TREE_CODE (t
) == LABEL_EXPR
)
2716 t
= LABEL_EXPR_LABEL (t
);
2717 uid
= LABEL_DECL_UID (t
);
2720 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2721 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2722 if (old_len
<= (unsigned) uid
)
2725 unsigned new_len
= 3 * uid
/ 2;
2727 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2729 addr
= VEC_address (basic_block
, label_to_block_map
);
2730 memset (&addr
[old_len
],
2731 0, sizeof (basic_block
) * (new_len
- old_len
));
2735 /* We're moving an existing label. Make sure that we've
2736 removed it from the old block. */
2738 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2739 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2744 /* Finds iterator for STMT. */
2746 extern block_stmt_iterator
2747 bsi_for_stmt (tree stmt
)
2749 block_stmt_iterator bsi
;
2751 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2752 if (bsi_stmt (bsi
) == stmt
)
2758 /* Mark statement T as modified, and update it. */
2760 update_modified_stmts (tree t
)
2762 if (TREE_CODE (t
) == STATEMENT_LIST
)
2764 tree_stmt_iterator i
;
2766 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2768 stmt
= tsi_stmt (i
);
2769 update_stmt_if_modified (stmt
);
2773 update_stmt_if_modified (t
);
2776 /* Insert statement (or statement list) T before the statement
2777 pointed-to by iterator I. M specifies how to update iterator I
2778 after insertion (see enum bsi_iterator_update). */
2781 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2783 set_bb_for_stmt (t
, i
->bb
);
2784 update_modified_stmts (t
);
2785 tsi_link_before (&i
->tsi
, t
, m
);
2789 /* Insert statement (or statement list) T after the statement
2790 pointed-to by iterator I. M specifies how to update iterator I
2791 after insertion (see enum bsi_iterator_update). */
2794 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2796 set_bb_for_stmt (t
, i
->bb
);
2797 update_modified_stmts (t
);
2798 tsi_link_after (&i
->tsi
, t
, m
);
2802 /* Remove the statement pointed to by iterator I. The iterator is updated
2803 to the next statement. */
2806 bsi_remove (block_stmt_iterator
*i
)
2808 tree t
= bsi_stmt (*i
);
2809 set_bb_for_stmt (t
, NULL
);
2810 delink_stmt_imm_use (t
);
2811 tsi_delink (&i
->tsi
);
2812 mark_stmt_modified (t
);
2816 /* Move the statement at FROM so it comes right after the statement at TO. */
2819 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2821 tree stmt
= bsi_stmt (*from
);
2823 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2827 /* Move the statement at FROM so it comes right before the statement at TO. */
2830 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2832 tree stmt
= bsi_stmt (*from
);
2834 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2838 /* Move the statement at FROM to the end of basic block BB. */
2841 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2843 block_stmt_iterator last
= bsi_last (bb
);
2845 /* Have to check bsi_end_p because it could be an empty block. */
2846 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2847 bsi_move_before (from
, &last
);
2849 bsi_move_after (from
, &last
);
2853 /* Replace the contents of the statement pointed to by iterator BSI
2854 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2855 information of the original statement is preserved. */
2858 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2861 tree orig_stmt
= bsi_stmt (*bsi
);
2863 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2864 set_bb_for_stmt (stmt
, bsi
->bb
);
2866 /* Preserve EH region information from the original statement, if
2867 requested by the caller. */
2868 if (preserve_eh_info
)
2870 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2873 remove_stmt_from_eh_region (stmt
);
2874 add_stmt_to_eh_region (stmt
, eh_region
);
2878 delink_stmt_imm_use (orig_stmt
);
2879 *bsi_stmt_ptr (*bsi
) = stmt
;
2880 mark_stmt_modified (stmt
);
2881 update_modified_stmts (stmt
);
2885 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2886 is made to place the statement in an existing basic block, but
2887 sometimes that isn't possible. When it isn't possible, the edge is
2888 split and the statement is added to the new block.
2890 In all cases, the returned *BSI points to the correct location. The
2891 return value is true if insertion should be done after the location,
2892 or false if it should be done before the location. If new basic block
2893 has to be created, it is stored in *NEW_BB. */
2896 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2897 basic_block
*new_bb
)
2899 basic_block dest
, src
;
2905 /* If the destination has one predecessor which has no PHI nodes,
2906 insert there. Except for the exit block.
2908 The requirement for no PHI nodes could be relaxed. Basically we
2909 would have to examine the PHIs to prove that none of them used
2910 the value set by the statement we want to insert on E. That
2911 hardly seems worth the effort. */
2912 if (single_pred_p (dest
)
2913 && ! phi_nodes (dest
)
2914 && dest
!= EXIT_BLOCK_PTR
)
2916 *bsi
= bsi_start (dest
);
2917 if (bsi_end_p (*bsi
))
2920 /* Make sure we insert after any leading labels. */
2921 tmp
= bsi_stmt (*bsi
);
2922 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2925 if (bsi_end_p (*bsi
))
2927 tmp
= bsi_stmt (*bsi
);
2930 if (bsi_end_p (*bsi
))
2932 *bsi
= bsi_last (dest
);
2939 /* If the source has one successor, the edge is not abnormal and
2940 the last statement does not end a basic block, insert there.
2941 Except for the entry block. */
2943 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2944 && single_succ_p (src
)
2945 && src
!= ENTRY_BLOCK_PTR
)
2947 *bsi
= bsi_last (src
);
2948 if (bsi_end_p (*bsi
))
2951 tmp
= bsi_stmt (*bsi
);
2952 if (!stmt_ends_bb_p (tmp
))
2955 /* Insert code just before returning the value. We may need to decompose
2956 the return in the case it contains non-trivial operand. */
2957 if (TREE_CODE (tmp
) == RETURN_EXPR
)
2959 tree op
= TREE_OPERAND (tmp
, 0);
2960 if (op
&& !is_gimple_val (op
))
2962 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
2963 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
2964 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
2971 /* Otherwise, create a new basic block, and split this edge. */
2972 dest
= split_edge (e
);
2975 e
= single_pred_edge (dest
);
2980 /* This routine will commit all pending edge insertions, creating any new
2981 basic blocks which are necessary. */
2984 bsi_commit_edge_inserts (void)
2990 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
2993 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2994 bsi_commit_one_edge_insert (e
, NULL
);
2998 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2999 to this block, otherwise set it to NULL. */
3002 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3006 if (PENDING_STMT (e
))
3008 block_stmt_iterator bsi
;
3009 tree stmt
= PENDING_STMT (e
);
3011 PENDING_STMT (e
) = NULL_TREE
;
3013 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3014 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3016 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3021 /* Add STMT to the pending list of edge E. No actual insertion is
3022 made until a call to bsi_commit_edge_inserts () is made. */
3025 bsi_insert_on_edge (edge e
, tree stmt
)
3027 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3030 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3031 block has to be created, it is returned. */
3034 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3036 block_stmt_iterator bsi
;
3037 basic_block new_bb
= NULL
;
3039 gcc_assert (!PENDING_STMT (e
));
3041 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3042 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3044 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3049 /*---------------------------------------------------------------------------
3050 Tree specific functions for CFG manipulation
3051 ---------------------------------------------------------------------------*/
3053 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3056 reinstall_phi_args (edge new_edge
, edge old_edge
)
3060 if (!PENDING_STMT (old_edge
))
3063 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3065 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3067 tree result
= TREE_PURPOSE (var
);
3068 tree arg
= TREE_VALUE (var
);
3070 gcc_assert (result
== PHI_RESULT (phi
));
3072 add_phi_arg (phi
, arg
, new_edge
);
3075 PENDING_STMT (old_edge
) = NULL
;
3078 /* Returns the basic block after that the new basic block created
3079 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3080 near its "logical" location. This is of most help to humans looking
3081 at debugging dumps. */
3084 split_edge_bb_loc (edge edge_in
)
3086 basic_block dest
= edge_in
->dest
;
3088 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3089 return edge_in
->src
;
3091 return dest
->prev_bb
;
3094 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3095 Abort on abnormal edges. */
3098 tree_split_edge (edge edge_in
)
3100 basic_block new_bb
, after_bb
, dest
, src
;
3103 /* Abnormal edges cannot be split. */
3104 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3107 dest
= edge_in
->dest
;
3109 after_bb
= split_edge_bb_loc (edge_in
);
3111 new_bb
= create_empty_bb (after_bb
);
3112 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3113 new_bb
->count
= edge_in
->count
;
3114 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3115 new_edge
->probability
= REG_BR_PROB_BASE
;
3116 new_edge
->count
= edge_in
->count
;
3118 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3120 reinstall_phi_args (new_edge
, e
);
3126 /* Return true when BB has label LABEL in it. */
3129 has_label_p (basic_block bb
, tree label
)
3131 block_stmt_iterator bsi
;
3133 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3135 tree stmt
= bsi_stmt (bsi
);
3137 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3139 if (LABEL_EXPR_LABEL (stmt
) == label
)
3146 /* Callback for walk_tree, check that all elements with address taken are
3147 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3148 inside a PHI node. */
3151 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3154 bool in_phi
= (data
!= NULL
);
3159 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3160 #define CHECK_OP(N, MSG) \
3161 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3162 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3164 switch (TREE_CODE (t
))
3167 if (SSA_NAME_IN_FREE_LIST (t
))
3169 error ("SSA name in freelist but still referenced");
3175 x
= fold (ASSERT_EXPR_COND (t
));
3176 if (x
== boolean_false_node
)
3178 error ("ASSERT_EXPR with an always-false condition");
3184 x
= TREE_OPERAND (t
, 0);
3185 if (TREE_CODE (x
) == BIT_FIELD_REF
3186 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3188 error ("GIMPLE register modified with BIT_FIELD_REF");
3197 bool old_side_effects
;
3200 bool new_side_effects
;
3202 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3203 dead PHIs that take the address of something. But if the PHI
3204 result is dead, the fact that it takes the address of anything
3205 is irrelevant. Because we can not tell from here if a PHI result
3206 is dead, we just skip this check for PHIs altogether. This means
3207 we may be missing "valid" checks, but what can you do?
3208 This was PR19217. */
3212 old_invariant
= TREE_INVARIANT (t
);
3213 old_constant
= TREE_CONSTANT (t
);
3214 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3216 recompute_tree_invariant_for_addr_expr (t
);
3217 new_invariant
= TREE_INVARIANT (t
);
3218 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3219 new_constant
= TREE_CONSTANT (t
);
3221 if (old_invariant
!= new_invariant
)
3223 error ("invariant not recomputed when ADDR_EXPR changed");
3227 if (old_constant
!= new_constant
)
3229 error ("constant not recomputed when ADDR_EXPR changed");
3232 if (old_side_effects
!= new_side_effects
)
3234 error ("side effects not recomputed when ADDR_EXPR changed");
3238 /* Skip any references (they will be checked when we recurse down the
3239 tree) and ensure that any variable used as a prefix is marked
3241 for (x
= TREE_OPERAND (t
, 0);
3242 handled_component_p (x
);
3243 x
= TREE_OPERAND (x
, 0))
3246 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3248 if (!TREE_ADDRESSABLE (x
))
3250 error ("address taken, but ADDRESSABLE bit not set");
3257 x
= COND_EXPR_COND (t
);
3258 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3260 error ("non-boolean used in condition");
3263 if (!is_gimple_condexpr (x
))
3265 error ("invalid conditional operand");
3272 case FIX_TRUNC_EXPR
:
3274 case FIX_FLOOR_EXPR
:
3275 case FIX_ROUND_EXPR
:
3280 case NON_LVALUE_EXPR
:
3281 case TRUTH_NOT_EXPR
:
3282 CHECK_OP (0, "invalid operand to unary operator");
3289 case ARRAY_RANGE_REF
:
3291 case VIEW_CONVERT_EXPR
:
3292 /* We have a nest of references. Verify that each of the operands
3293 that determine where to reference is either a constant or a variable,
3294 verify that the base is valid, and then show we've already checked
3296 while (handled_component_p (t
))
3298 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3299 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3300 else if (TREE_CODE (t
) == ARRAY_REF
3301 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3303 CHECK_OP (1, "invalid array index");
3304 if (TREE_OPERAND (t
, 2))
3305 CHECK_OP (2, "invalid array lower bound");
3306 if (TREE_OPERAND (t
, 3))
3307 CHECK_OP (3, "invalid array stride");
3309 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3311 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3312 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3315 t
= TREE_OPERAND (t
, 0);
3318 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3320 error ("invalid reference prefix");
3332 case UNORDERED_EXPR
:
3343 case TRUNC_DIV_EXPR
:
3345 case FLOOR_DIV_EXPR
:
3346 case ROUND_DIV_EXPR
:
3347 case TRUNC_MOD_EXPR
:
3349 case FLOOR_MOD_EXPR
:
3350 case ROUND_MOD_EXPR
:
3352 case EXACT_DIV_EXPR
:
3362 CHECK_OP (0, "invalid operand to binary operator");
3363 CHECK_OP (1, "invalid operand to binary operator");
3375 /* Verify STMT, return true if STMT is not in GIMPLE form.
3376 TODO: Implement type checking. */
3379 verify_stmt (tree stmt
, bool last_in_block
)
3383 if (!is_gimple_stmt (stmt
))
3385 error ("is not a valid GIMPLE statement");
3389 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3392 debug_generic_stmt (addr
);
3396 /* If the statement is marked as part of an EH region, then it is
3397 expected that the statement could throw. Verify that when we
3398 have optimizations that simplify statements such that we prove
3399 that they cannot throw, that we update other data structures
3401 if (lookup_stmt_eh_region (stmt
) >= 0)
3403 if (!tree_could_throw_p (stmt
))
3405 error ("statement marked for throw, but doesn%'t");
3408 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3410 error ("statement marked for throw in middle of block");
3418 debug_generic_stmt (stmt
);
3423 /* Return true when the T can be shared. */
3426 tree_node_can_be_shared (tree t
)
3428 if (IS_TYPE_OR_DECL_P (t
)
3429 /* We check for constants explicitly since they are not considered
3430 gimple invariants if they overflowed. */
3431 || CONSTANT_CLASS_P (t
)
3432 || is_gimple_min_invariant (t
)
3433 || TREE_CODE (t
) == SSA_NAME
3434 || t
== error_mark_node
)
3437 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3440 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3441 /* We check for constants explicitly since they are not considered
3442 gimple invariants if they overflowed. */
3443 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3444 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3445 || (TREE_CODE (t
) == COMPONENT_REF
3446 || TREE_CODE (t
) == REALPART_EXPR
3447 || TREE_CODE (t
) == IMAGPART_EXPR
))
3448 t
= TREE_OPERAND (t
, 0);
3457 /* Called via walk_trees. Verify tree sharing. */
3460 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3462 htab_t htab
= (htab_t
) data
;
3465 if (tree_node_can_be_shared (*tp
))
3467 *walk_subtrees
= false;
3471 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3473 return (tree
) *slot
;
3480 /* Verify the GIMPLE statement chain. */
3486 block_stmt_iterator bsi
;
3491 timevar_push (TV_TREE_STMT_VERIFY
);
3492 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3499 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3501 int phi_num_args
= PHI_NUM_ARGS (phi
);
3503 if (bb_for_stmt (phi
) != bb
)
3505 error ("bb_for_stmt (phi) is set to a wrong basic block");
3509 for (i
= 0; i
< phi_num_args
; i
++)
3511 tree t
= PHI_ARG_DEF (phi
, i
);
3514 /* Addressable variables do have SSA_NAMEs but they
3515 are not considered gimple values. */
3516 if (TREE_CODE (t
) != SSA_NAME
3517 && TREE_CODE (t
) != FUNCTION_DECL
3518 && !is_gimple_val (t
))
3520 error ("PHI def is not a GIMPLE value");
3521 debug_generic_stmt (phi
);
3522 debug_generic_stmt (t
);
3526 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3529 debug_generic_stmt (addr
);
3533 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3536 error ("incorrect sharing of tree nodes");
3537 debug_generic_stmt (phi
);
3538 debug_generic_stmt (addr
);
3544 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3546 tree stmt
= bsi_stmt (bsi
);
3548 if (bb_for_stmt (stmt
) != bb
)
3550 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3555 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3556 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3559 error ("incorrect sharing of tree nodes");
3560 debug_generic_stmt (stmt
);
3561 debug_generic_stmt (addr
);
3568 internal_error ("verify_stmts failed");
3571 timevar_pop (TV_TREE_STMT_VERIFY
);
3575 /* Verifies that the flow information is OK. */
3578 tree_verify_flow_info (void)
3582 block_stmt_iterator bsi
;
3587 if (ENTRY_BLOCK_PTR
->stmt_list
)
3589 error ("ENTRY_BLOCK has a statement list associated with it");
3593 if (EXIT_BLOCK_PTR
->stmt_list
)
3595 error ("EXIT_BLOCK has a statement list associated with it");
3599 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3600 if (e
->flags
& EDGE_FALLTHRU
)
3602 error ("fallthru to exit from bb %d", e
->src
->index
);
3608 bool found_ctrl_stmt
= false;
3612 /* Skip labels on the start of basic block. */
3613 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3615 tree prev_stmt
= stmt
;
3617 stmt
= bsi_stmt (bsi
);
3619 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3622 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3624 error ("nonlocal label %s is not first "
3625 "in a sequence of labels in bb %d",
3626 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3631 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3633 error ("label %s to block does not match in bb %d",
3634 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3639 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3640 != current_function_decl
)
3642 error ("label %s has incorrect context in bb %d",
3643 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3649 /* Verify that body of basic block BB is free of control flow. */
3650 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3652 tree stmt
= bsi_stmt (bsi
);
3654 if (found_ctrl_stmt
)
3656 error ("control flow in the middle of basic block %d",
3661 if (stmt_ends_bb_p (stmt
))
3662 found_ctrl_stmt
= true;
3664 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3666 error ("label %s in the middle of basic block %d",
3667 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3672 bsi
= bsi_last (bb
);
3673 if (bsi_end_p (bsi
))
3676 stmt
= bsi_stmt (bsi
);
3678 err
|= verify_eh_edges (stmt
);
3680 if (is_ctrl_stmt (stmt
))
3682 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3683 if (e
->flags
& EDGE_FALLTHRU
)
3685 error ("fallthru edge after a control statement in bb %d",
3691 switch (TREE_CODE (stmt
))
3697 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3698 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3700 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3704 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3706 if (!true_edge
|| !false_edge
3707 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3708 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3709 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3710 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3711 || EDGE_COUNT (bb
->succs
) >= 3)
3713 error ("wrong outgoing edge flags at end of bb %d",
3718 if (!has_label_p (true_edge
->dest
,
3719 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3721 error ("%<then%> label does not match edge at end of bb %d",
3726 if (!has_label_p (false_edge
->dest
,
3727 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3729 error ("%<else%> label does not match edge at end of bb %d",
3737 if (simple_goto_p (stmt
))
3739 error ("explicit goto at end of bb %d", bb
->index
);
3744 /* FIXME. We should double check that the labels in the
3745 destination blocks have their address taken. */
3746 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3747 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3748 | EDGE_FALSE_VALUE
))
3749 || !(e
->flags
& EDGE_ABNORMAL
))
3751 error ("wrong outgoing edge flags at end of bb %d",
3759 if (!single_succ_p (bb
)
3760 || (single_succ_edge (bb
)->flags
3761 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3762 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3764 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3767 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3769 error ("return edge does not point to exit in bb %d",
3782 vec
= SWITCH_LABELS (stmt
);
3783 n
= TREE_VEC_LENGTH (vec
);
3785 /* Mark all the destination basic blocks. */
3786 for (i
= 0; i
< n
; ++i
)
3788 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3789 basic_block label_bb
= label_to_block (lab
);
3791 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3792 label_bb
->aux
= (void *)1;
3795 /* Verify that the case labels are sorted. */
3796 prev
= TREE_VEC_ELT (vec
, 0);
3797 for (i
= 1; i
< n
- 1; ++i
)
3799 tree c
= TREE_VEC_ELT (vec
, i
);
3802 error ("found default case not at end of case vector");
3806 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3808 error ("case labels not sorted:");
3809 print_generic_expr (stderr
, prev
, 0);
3810 fprintf (stderr
," is greater than ");
3811 print_generic_expr (stderr
, c
, 0);
3812 fprintf (stderr
," but comes before it.\n");
3817 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3819 error ("no default case found at end of case vector");
3823 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3827 error ("extra outgoing edge %d->%d",
3828 bb
->index
, e
->dest
->index
);
3831 e
->dest
->aux
= (void *)2;
3832 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3833 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3835 error ("wrong outgoing edge flags at end of bb %d",
3841 /* Check that we have all of them. */
3842 for (i
= 0; i
< n
; ++i
)
3844 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3845 basic_block label_bb
= label_to_block (lab
);
3847 if (label_bb
->aux
!= (void *)2)
3849 error ("missing edge %i->%i",
3850 bb
->index
, label_bb
->index
);
3855 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3856 e
->dest
->aux
= (void *)0;
3863 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3864 verify_dominators (CDI_DOMINATORS
);
3870 /* Updates phi nodes after creating a forwarder block joined
3871 by edge FALLTHRU. */
3874 tree_make_forwarder_block (edge fallthru
)
3878 basic_block dummy
, bb
;
3879 tree phi
, new_phi
, var
;
3881 dummy
= fallthru
->src
;
3882 bb
= fallthru
->dest
;
3884 if (single_pred_p (bb
))
3887 /* If we redirected a branch we must create new phi nodes at the
3889 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3891 var
= PHI_RESULT (phi
);
3892 new_phi
= create_phi_node (var
, bb
);
3893 SSA_NAME_DEF_STMT (var
) = new_phi
;
3894 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3895 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3898 /* Ensure that the PHI node chain is in the same order. */
3899 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3901 /* Add the arguments we have stored on edges. */
3902 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3907 flush_pending_stmts (e
);
3912 /* Return a non-special label in the head of basic block BLOCK.
3913 Create one if it doesn't exist. */
3916 tree_block_label (basic_block bb
)
3918 block_stmt_iterator i
, s
= bsi_start (bb
);
3922 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3924 stmt
= bsi_stmt (i
);
3925 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3927 label
= LABEL_EXPR_LABEL (stmt
);
3928 if (!DECL_NONLOCAL (label
))
3931 bsi_move_before (&i
, &s
);
3936 label
= create_artificial_label ();
3937 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3938 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3943 /* Attempt to perform edge redirection by replacing a possibly complex
3944 jump instruction by a goto or by removing the jump completely.
3945 This can apply only if all edges now point to the same block. The
3946 parameters and return values are equivalent to
3947 redirect_edge_and_branch. */
3950 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
3952 basic_block src
= e
->src
;
3953 block_stmt_iterator b
;
3956 /* We can replace or remove a complex jump only when we have exactly
3958 if (EDGE_COUNT (src
->succs
) != 2
3959 /* Verify that all targets will be TARGET. Specifically, the
3960 edge that is not E must also go to TARGET. */
3961 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
3967 stmt
= bsi_stmt (b
);
3969 if (TREE_CODE (stmt
) == COND_EXPR
3970 || TREE_CODE (stmt
) == SWITCH_EXPR
)
3973 e
= ssa_redirect_edge (e
, target
);
3974 e
->flags
= EDGE_FALLTHRU
;
3982 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3983 edge representing the redirected branch. */
3986 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
3988 basic_block bb
= e
->src
;
3989 block_stmt_iterator bsi
;
3993 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3996 if (e
->src
!= ENTRY_BLOCK_PTR
3997 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4000 if (e
->dest
== dest
)
4003 label
= tree_block_label (dest
);
4005 bsi
= bsi_last (bb
);
4006 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4008 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4011 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4012 ? COND_EXPR_THEN (stmt
)
4013 : COND_EXPR_ELSE (stmt
));
4014 GOTO_DESTINATION (stmt
) = label
;
4018 /* No non-abnormal edges should lead from a non-simple goto, and
4019 simple ones should be represented implicitly. */
4024 tree cases
= get_cases_for_edge (e
, stmt
);
4026 /* If we have a list of cases associated with E, then use it
4027 as it's a lot faster than walking the entire case vector. */
4030 edge e2
= find_edge (e
->src
, dest
);
4037 CASE_LABEL (cases
) = label
;
4038 cases
= TREE_CHAIN (cases
);
4041 /* If there was already an edge in the CFG, then we need
4042 to move all the cases associated with E to E2. */
4045 tree cases2
= get_cases_for_edge (e2
, stmt
);
4047 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4048 TREE_CHAIN (cases2
) = first
;
4053 tree vec
= SWITCH_LABELS (stmt
);
4054 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4056 for (i
= 0; i
< n
; i
++)
4058 tree elt
= TREE_VEC_ELT (vec
, i
);
4060 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4061 CASE_LABEL (elt
) = label
;
4070 e
->flags
|= EDGE_FALLTHRU
;
4074 /* Otherwise it must be a fallthru edge, and we don't need to
4075 do anything besides redirecting it. */
4076 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4080 /* Update/insert PHI nodes as necessary. */
4082 /* Now update the edges in the CFG. */
4083 e
= ssa_redirect_edge (e
, dest
);
4089 /* Simple wrapper, as we can always redirect fallthru edges. */
4092 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4094 e
= tree_redirect_edge_and_branch (e
, dest
);
4101 /* Splits basic block BB after statement STMT (but at least after the
4102 labels). If STMT is NULL, BB is split just after the labels. */
4105 tree_split_block (basic_block bb
, void *stmt
)
4107 block_stmt_iterator bsi
, bsi_tgt
;
4113 new_bb
= create_empty_bb (bb
);
4115 /* Redirect the outgoing edges. */
4116 new_bb
->succs
= bb
->succs
;
4118 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4121 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4124 /* Move everything from BSI to the new basic block. */
4125 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4127 act
= bsi_stmt (bsi
);
4128 if (TREE_CODE (act
) == LABEL_EXPR
)
4141 bsi_tgt
= bsi_start (new_bb
);
4142 while (!bsi_end_p (bsi
))
4144 act
= bsi_stmt (bsi
);
4146 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4153 /* Moves basic block BB after block AFTER. */
4156 tree_move_block_after (basic_block bb
, basic_block after
)
4158 if (bb
->prev_bb
== after
)
4162 link_block (bb
, after
);
4168 /* Return true if basic_block can be duplicated. */
4171 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4177 /* Create a duplicate of the basic block BB. NOTE: This does not
4178 preserve SSA form. */
4181 tree_duplicate_bb (basic_block bb
)
4184 block_stmt_iterator bsi
, bsi_tgt
;
4187 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4189 /* Copy the PHI nodes. We ignore PHI node arguments here because
4190 the incoming edges have not been setup yet. */
4191 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4193 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4194 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4197 /* Keep the chain of PHI nodes in the same order so that they can be
4198 updated by ssa_redirect_edge. */
4199 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4201 bsi_tgt
= bsi_start (new_bb
);
4202 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4204 def_operand_p def_p
;
4205 ssa_op_iter op_iter
;
4209 stmt
= bsi_stmt (bsi
);
4210 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4213 /* Create a new copy of STMT and duplicate STMT's virtual
4215 copy
= unshare_expr (stmt
);
4216 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4217 copy_virtual_operands (copy
, stmt
);
4218 region
= lookup_stmt_eh_region (stmt
);
4220 add_stmt_to_eh_region (copy
, region
);
4222 /* Create new names for all the definitions created by COPY and
4223 add replacement mappings for each new name. */
4224 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4225 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4232 /* Basic block BB_COPY was created by code duplication. Add phi node
4233 arguments for edges going out of BB_COPY. The blocks that were
4234 duplicated have BB_DUPLICATED set. */
4237 add_phi_args_after_copy_bb (basic_block bb_copy
)
4239 basic_block bb
, dest
;
4242 tree phi
, phi_copy
, phi_next
, def
;
4244 bb
= get_bb_original (bb_copy
);
4246 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4248 if (!phi_nodes (e_copy
->dest
))
4251 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4252 dest
= get_bb_original (e_copy
->dest
);
4254 dest
= e_copy
->dest
;
4256 e
= find_edge (bb
, dest
);
4259 /* During loop unrolling the target of the latch edge is copied.
4260 In this case we are not looking for edge to dest, but to
4261 duplicated block whose original was dest. */
4262 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4263 if ((e
->dest
->flags
& BB_DUPLICATED
)
4264 && get_bb_original (e
->dest
) == dest
)
4267 gcc_assert (e
!= NULL
);
4270 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4272 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4274 phi_next
= PHI_CHAIN (phi
);
4275 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4276 add_phi_arg (phi_copy
, def
, e_copy
);
4281 /* Blocks in REGION_COPY array of length N_REGION were created by
4282 duplication of basic blocks. Add phi node arguments for edges
4283 going from these blocks. */
4286 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4290 for (i
= 0; i
< n_region
; i
++)
4291 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4293 for (i
= 0; i
< n_region
; i
++)
4294 add_phi_args_after_copy_bb (region_copy
[i
]);
4296 for (i
= 0; i
< n_region
; i
++)
4297 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4300 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4301 important exit edge EXIT. By important we mean that no SSA name defined
4302 inside region is live over the other exit edges of the region. All entry
4303 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4304 to the duplicate of the region. SSA form, dominance and loop information
4305 is updated. The new basic blocks are stored to REGION_COPY in the same
4306 order as they had in REGION, provided that REGION_COPY is not NULL.
4307 The function returns false if it is unable to copy the region,
4311 tree_duplicate_sese_region (edge entry
, edge exit
,
4312 basic_block
*region
, unsigned n_region
,
4313 basic_block
*region_copy
)
4316 bool free_region_copy
= false, copying_header
= false;
4317 struct loop
*loop
= entry
->dest
->loop_father
;
4321 int total_freq
= 0, entry_freq
= 0;
4322 gcov_type total_count
= 0, entry_count
= 0;
4324 if (!can_copy_bbs_p (region
, n_region
))
4327 /* Some sanity checking. Note that we do not check for all possible
4328 missuses of the functions. I.e. if you ask to copy something weird,
4329 it will work, but the state of structures probably will not be
4331 for (i
= 0; i
< n_region
; i
++)
4333 /* We do not handle subloops, i.e. all the blocks must belong to the
4335 if (region
[i
]->loop_father
!= loop
)
4338 if (region
[i
] != entry
->dest
4339 && region
[i
] == loop
->header
)
4345 /* In case the function is used for loop header copying (which is the primary
4346 use), ensure that EXIT and its copy will be new latch and entry edges. */
4347 if (loop
->header
== entry
->dest
)
4349 copying_header
= true;
4350 loop
->copy
= loop
->outer
;
4352 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4355 for (i
= 0; i
< n_region
; i
++)
4356 if (region
[i
] != exit
->src
4357 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4363 region_copy
= XNEWVEC (basic_block
, n_region
);
4364 free_region_copy
= true;
4367 gcc_assert (!need_ssa_update_p ());
4369 /* Record blocks outside the region that are dominated by something
4371 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4372 initialize_original_copy_tables ();
4374 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4376 if (entry
->dest
->count
)
4378 total_count
= entry
->dest
->count
;
4379 entry_count
= entry
->count
;
4380 /* Fix up corner cases, to avoid division by zero or creation of negative
4382 if (entry_count
> total_count
)
4383 entry_count
= total_count
;
4387 total_freq
= entry
->dest
->frequency
;
4388 entry_freq
= EDGE_FREQUENCY (entry
);
4389 /* Fix up corner cases, to avoid division by zero or creation of negative
4391 if (total_freq
== 0)
4393 else if (entry_freq
> total_freq
)
4394 entry_freq
= total_freq
;
4397 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4398 split_edge_bb_loc (entry
));
4401 scale_bbs_frequencies_gcov_type (region
, n_region
,
4402 total_count
- entry_count
,
4404 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4409 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4411 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4416 loop
->header
= exit
->dest
;
4417 loop
->latch
= exit
->src
;
4420 /* Redirect the entry and add the phi node arguments. */
4421 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4422 gcc_assert (redirected
!= NULL
);
4423 flush_pending_stmts (entry
);
4425 /* Concerning updating of dominators: We must recount dominators
4426 for entry block and its copy. Anything that is outside of the
4427 region, but was dominated by something inside needs recounting as
4429 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4430 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4431 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4434 /* Add the other PHI node arguments. */
4435 add_phi_args_after_copy (region_copy
, n_region
);
4437 /* Update the SSA web. */
4438 update_ssa (TODO_update_ssa
);
4440 if (free_region_copy
)
4443 free_original_copy_tables ();
4448 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4451 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4453 tree arg
, vars
, var
;
4454 bool ignore_topmost_bind
= false, any_var
= false;
4458 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4460 arg
= DECL_ARGUMENTS (fn
);
4463 print_generic_expr (file
, arg
, dump_flags
);
4464 if (TREE_CHAIN (arg
))
4465 fprintf (file
, ", ");
4466 arg
= TREE_CHAIN (arg
);
4468 fprintf (file
, ")\n");
4470 if (flags
& TDF_DETAILS
)
4471 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4472 if (flags
& TDF_RAW
)
4474 dump_node (fn
, TDF_SLIM
| flags
, file
);
4478 /* When GIMPLE is lowered, the variables are no longer available in
4479 BIND_EXPRs, so display them separately. */
4480 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4482 ignore_topmost_bind
= true;
4484 fprintf (file
, "{\n");
4485 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4487 var
= TREE_VALUE (vars
);
4489 print_generic_decl (file
, var
, flags
);
4490 fprintf (file
, "\n");
4496 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4498 /* Make a CFG based dump. */
4499 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4500 if (!ignore_topmost_bind
)
4501 fprintf (file
, "{\n");
4503 if (any_var
&& n_basic_blocks
)
4504 fprintf (file
, "\n");
4507 dump_generic_bb (file
, bb
, 2, flags
);
4509 fprintf (file
, "}\n");
4510 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4516 /* Make a tree based dump. */
4517 chain
= DECL_SAVED_TREE (fn
);
4519 if (TREE_CODE (chain
) == BIND_EXPR
)
4521 if (ignore_topmost_bind
)
4523 chain
= BIND_EXPR_BODY (chain
);
4531 if (!ignore_topmost_bind
)
4532 fprintf (file
, "{\n");
4537 fprintf (file
, "\n");
4539 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4540 if (ignore_topmost_bind
)
4541 fprintf (file
, "}\n");
4544 fprintf (file
, "\n\n");
4548 /* Pretty print of the loops intermediate representation. */
4549 static void print_loop (FILE *, struct loop
*, int);
4550 static void print_pred_bbs (FILE *, basic_block bb
);
4551 static void print_succ_bbs (FILE *, basic_block bb
);
4554 /* Print on FILE the indexes for the predecessors of basic_block BB. */
4557 print_pred_bbs (FILE *file
, basic_block bb
)
4562 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4563 fprintf (file
, "bb_%d ", e
->src
->index
);
4567 /* Print on FILE the indexes for the successors of basic_block BB. */
4570 print_succ_bbs (FILE *file
, basic_block bb
)
4575 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4576 fprintf (file
, "bb_%d ", e
->dest
->index
);
4580 /* Pretty print LOOP on FILE, indented INDENT spaces. */
4583 print_loop (FILE *file
, struct loop
*loop
, int indent
)
4591 s_indent
= (char *) alloca ((size_t) indent
+ 1);
4592 memset ((void *) s_indent
, ' ', (size_t) indent
);
4593 s_indent
[indent
] = '\0';
4595 /* Print the loop's header. */
4596 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
4598 /* Print the loop's body. */
4599 fprintf (file
, "%s{\n", s_indent
);
4601 if (bb
->loop_father
== loop
)
4603 /* Print the basic_block's header. */
4604 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
4605 print_pred_bbs (file
, bb
);
4606 fprintf (file
, "}, succs = {");
4607 print_succ_bbs (file
, bb
);
4608 fprintf (file
, "})\n");
4610 /* Print the basic_block's body. */
4611 fprintf (file
, "%s {\n", s_indent
);
4612 tree_dump_bb (bb
, file
, indent
+ 4);
4613 fprintf (file
, "%s }\n", s_indent
);
4616 print_loop (file
, loop
->inner
, indent
+ 2);
4617 fprintf (file
, "%s}\n", s_indent
);
4618 print_loop (file
, loop
->next
, indent
);
4622 /* Follow a CFG edge from the entry point of the program, and on entry
4623 of a loop, pretty print the loop structure on FILE. */
4626 print_loop_ir (FILE *file
)
4630 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
4631 if (bb
&& bb
->loop_father
)
4632 print_loop (file
, bb
->loop_father
, 0);
4636 /* Debugging loops structure at tree level. */
4639 debug_loop_ir (void)
4641 print_loop_ir (stderr
);
4645 /* Return true if BB ends with a call, possibly followed by some
4646 instructions that must stay with the call. Return false,
4650 tree_block_ends_with_call_p (basic_block bb
)
4652 block_stmt_iterator bsi
= bsi_last (bb
);
4653 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
4657 /* Return true if BB ends with a conditional branch. Return false,
4661 tree_block_ends_with_condjump_p (basic_block bb
)
4663 tree stmt
= last_stmt (bb
);
4664 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
4668 /* Return true if we need to add fake edge to exit at statement T.
4669 Helper function for tree_flow_call_edges_add. */
4672 need_fake_edge_p (tree t
)
4676 /* NORETURN and LONGJMP calls already have an edge to exit.
4677 CONST and PURE calls do not need one.
4678 We don't currently check for CONST and PURE here, although
4679 it would be a good idea, because those attributes are
4680 figured out from the RTL in mark_constant_function, and
4681 the counter incrementation code from -fprofile-arcs
4682 leads to different results from -fbranch-probabilities. */
4683 call
= get_call_expr_in (t
);
4685 && !(call_expr_flags (call
) & ECF_NORETURN
))
4688 if (TREE_CODE (t
) == ASM_EXPR
4689 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
4696 /* Add fake edges to the function exit for any non constant and non
4697 noreturn calls, volatile inline assembly in the bitmap of blocks
4698 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
4699 the number of blocks that were split.
4701 The goal is to expose cases in which entering a basic block does
4702 not imply that all subsequent instructions must be executed. */
4705 tree_flow_call_edges_add (sbitmap blocks
)
4708 int blocks_split
= 0;
4709 int last_bb
= last_basic_block
;
4710 bool check_last_block
= false;
4712 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
4716 check_last_block
= true;
4718 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
4720 /* In the last basic block, before epilogue generation, there will be
4721 a fallthru edge to EXIT. Special care is required if the last insn
4722 of the last basic block is a call because make_edge folds duplicate
4723 edges, which would result in the fallthru edge also being marked
4724 fake, which would result in the fallthru edge being removed by
4725 remove_fake_edges, which would result in an invalid CFG.
4727 Moreover, we can't elide the outgoing fake edge, since the block
4728 profiler needs to take this into account in order to solve the minimal
4729 spanning tree in the case that the call doesn't return.
4731 Handle this by adding a dummy instruction in a new last basic block. */
4732 if (check_last_block
)
4734 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
4735 block_stmt_iterator bsi
= bsi_last (bb
);
4737 if (!bsi_end_p (bsi
))
4740 if (t
&& need_fake_edge_p (t
))
4744 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4747 bsi_insert_on_edge (e
, build_empty_stmt ());
4748 bsi_commit_edge_inserts ();
4753 /* Now add fake edges to the function exit for any non constant
4754 calls since there is no way that we can determine if they will
4756 for (i
= 0; i
< last_bb
; i
++)
4758 basic_block bb
= BASIC_BLOCK (i
);
4759 block_stmt_iterator bsi
;
4760 tree stmt
, last_stmt
;
4765 if (blocks
&& !TEST_BIT (blocks
, i
))
4768 bsi
= bsi_last (bb
);
4769 if (!bsi_end_p (bsi
))
4771 last_stmt
= bsi_stmt (bsi
);
4774 stmt
= bsi_stmt (bsi
);
4775 if (need_fake_edge_p (stmt
))
4778 /* The handling above of the final block before the
4779 epilogue should be enough to verify that there is
4780 no edge to the exit block in CFG already.
4781 Calling make_edge in such case would cause us to
4782 mark that edge as fake and remove it later. */
4783 #ifdef ENABLE_CHECKING
4784 if (stmt
== last_stmt
)
4786 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4787 gcc_assert (e
== NULL
);
4791 /* Note that the following may create a new basic block
4792 and renumber the existing basic blocks. */
4793 if (stmt
!= last_stmt
)
4795 e
= split_block (bb
, stmt
);
4799 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
4803 while (!bsi_end_p (bsi
));
4808 verify_flow_info ();
4810 return blocks_split
;
4814 tree_purge_dead_eh_edges (basic_block bb
)
4816 bool changed
= false;
4819 tree stmt
= last_stmt (bb
);
4821 if (stmt
&& tree_can_throw_internal (stmt
))
4824 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
4826 if (e
->flags
& EDGE_EH
)
4835 /* Removal of dead EH edges might change dominators of not
4836 just immediate successors. E.g. when bb1 is changed so that
4837 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
4838 eh edges purged by this function in:
4850 idom(bb5) must be recomputed. For now just free the dominance
4853 free_dominance_info (CDI_DOMINATORS
);
4859 tree_purge_all_dead_eh_edges (bitmap blocks
)
4861 bool changed
= false;
4865 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
4867 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
4873 /* This function is called whenever a new edge is created or
4877 tree_execute_on_growing_pred (edge e
)
4879 basic_block bb
= e
->dest
;
4882 reserve_phi_args_for_new_edge (bb
);
4885 /* This function is called immediately before edge E is removed from
4886 the edge vector E->dest->preds. */
4889 tree_execute_on_shrinking_pred (edge e
)
4891 if (phi_nodes (e
->dest
))
4892 remove_phi_args (e
);
4895 /*---------------------------------------------------------------------------
4896 Helper functions for Loop versioning
4897 ---------------------------------------------------------------------------*/
4899 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
4900 of 'first'. Both of them are dominated by 'new_head' basic block. When
4901 'new_head' was created by 'second's incoming edge it received phi arguments
4902 on the edge by split_edge(). Later, additional edge 'e' was created to
4903 connect 'new_head' and 'first'. Now this routine adds phi args on this
4904 additional edge 'e' that new_head to second edge received as part of edge
4909 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
4910 basic_block new_head
, edge e
)
4913 edge e2
= find_edge (new_head
, second
);
4915 /* Because NEW_HEAD has been created by splitting SECOND's incoming
4916 edge, we should always have an edge from NEW_HEAD to SECOND. */
4917 gcc_assert (e2
!= NULL
);
4919 /* Browse all 'second' basic block phi nodes and add phi args to
4920 edge 'e' for 'first' head. PHI args are always in correct order. */
4922 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
4924 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
4926 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
4927 add_phi_arg (phi1
, def
, e
);
4931 /* Adds a if else statement to COND_BB with condition COND_EXPR.
4932 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
4933 the destination of the ELSE part. */
4935 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
4936 basic_block cond_bb
, void *cond_e
)
4938 block_stmt_iterator bsi
;
4939 tree goto1
= NULL_TREE
;
4940 tree goto2
= NULL_TREE
;
4941 tree new_cond_expr
= NULL_TREE
;
4942 tree cond_expr
= (tree
) cond_e
;
4945 /* Build new conditional expr */
4946 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
4947 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
4948 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
4950 /* Add new cond in cond_bb. */
4951 bsi
= bsi_start (cond_bb
);
4952 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
4953 /* Adjust edges appropriately to connect new head with first head
4954 as well as second head. */
4955 e0
= single_succ_edge (cond_bb
);
4956 e0
->flags
&= ~EDGE_FALLTHRU
;
4957 e0
->flags
|= EDGE_FALSE_VALUE
;
4960 struct cfg_hooks tree_cfg_hooks
= {
4962 tree_verify_flow_info
,
4963 tree_dump_bb
, /* dump_bb */
4964 create_bb
, /* create_basic_block */
4965 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
4966 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
4967 remove_bb
, /* delete_basic_block */
4968 tree_split_block
, /* split_block */
4969 tree_move_block_after
, /* move_block_after */
4970 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
4971 tree_merge_blocks
, /* merge_blocks */
4972 tree_predict_edge
, /* predict_edge */
4973 tree_predicted_by_p
, /* predicted_by_p */
4974 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
4975 tree_duplicate_bb
, /* duplicate_block */
4976 tree_split_edge
, /* split_edge */
4977 tree_make_forwarder_block
, /* make_forward_block */
4978 NULL
, /* tidy_fallthru_edge */
4979 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
4980 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
4981 tree_flow_call_edges_add
, /* flow_call_edges_add */
4982 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
4983 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
4984 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
4985 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
4986 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
4987 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
4988 flush_pending_stmts
/* flush_pending_stmts */
4992 /* Split all critical edges. */
4995 split_critical_edges (void)
5001 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5002 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5003 mappings around the calls to split_edge. */
5004 start_recording_case_labels ();
5007 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5008 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5013 end_recording_case_labels ();
5016 struct tree_opt_pass pass_split_crit_edges
=
5018 "crited", /* name */
5020 split_critical_edges
, /* execute */
5023 0, /* static_pass_number */
5024 TV_TREE_SPLIT_EDGES
, /* tv_id */
5025 PROP_cfg
, /* properties required */
5026 PROP_no_crit_edges
, /* properties_provided */
5027 0, /* properties_destroyed */
5028 0, /* todo_flags_start */
5029 TODO_dump_func
, /* todo_flags_finish */
5034 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5035 a temporary, make sure and register it to be renamed if necessary,
5036 and finally return the temporary. Put the statements to compute
5037 EXP before the current statement in BSI. */
5040 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5042 tree t
, new_stmt
, orig_stmt
;
5044 if (is_gimple_val (exp
))
5047 t
= make_rename_temp (type
, NULL
);
5048 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5050 orig_stmt
= bsi_stmt (*bsi
);
5051 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5052 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5054 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5059 /* Build a ternary operation and gimplify it. Emit code before BSI.
5060 Return the gimple_val holding the result. */
5063 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5064 tree type
, tree a
, tree b
, tree c
)
5068 ret
= fold_build3 (code
, type
, a
, b
, c
);
5071 return gimplify_val (bsi
, type
, ret
);
5074 /* Build a binary operation and gimplify it. Emit code before BSI.
5075 Return the gimple_val holding the result. */
5078 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5079 tree type
, tree a
, tree b
)
5083 ret
= fold_build2 (code
, type
, a
, b
);
5086 return gimplify_val (bsi
, type
, ret
);
5089 /* Build a unary operation and gimplify it. Emit code before BSI.
5090 Return the gimple_val holding the result. */
5093 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5098 ret
= fold_build1 (code
, type
, a
);
5101 return gimplify_val (bsi
, type
, ret
);
5106 /* Emit return warnings. */
5109 execute_warn_function_return (void)
5111 #ifdef USE_MAPPED_LOCATION
5112 source_location location
;
5120 /* If we have a path to EXIT, then we do return. */
5121 if (TREE_THIS_VOLATILE (cfun
->decl
)
5122 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5124 #ifdef USE_MAPPED_LOCATION
5125 location
= UNKNOWN_LOCATION
;
5129 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5131 last
= last_stmt (e
->src
);
5132 if (TREE_CODE (last
) == RETURN_EXPR
5133 #ifdef USE_MAPPED_LOCATION
5134 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5136 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5140 #ifdef USE_MAPPED_LOCATION
5141 if (location
== UNKNOWN_LOCATION
)
5142 location
= cfun
->function_end_locus
;
5143 warning (0, "%H%<noreturn%> function does return", &location
);
5146 locus
= &cfun
->function_end_locus
;
5147 warning (0, "%H%<noreturn%> function does return", locus
);
5151 /* If we see "return;" in some basic block, then we do reach the end
5152 without returning a value. */
5153 else if (warn_return_type
5154 && !TREE_NO_WARNING (cfun
->decl
)
5155 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5156 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5158 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5160 tree last
= last_stmt (e
->src
);
5161 if (TREE_CODE (last
) == RETURN_EXPR
5162 && TREE_OPERAND (last
, 0) == NULL
5163 && !TREE_NO_WARNING (last
))
5165 #ifdef USE_MAPPED_LOCATION
5166 location
= EXPR_LOCATION (last
);
5167 if (location
== UNKNOWN_LOCATION
)
5168 location
= cfun
->function_end_locus
;
5169 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5171 locus
= EXPR_LOCUS (last
);
5173 locus
= &cfun
->function_end_locus
;
5174 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5176 TREE_NO_WARNING (cfun
->decl
) = 1;
5184 /* Given a basic block B which ends with a conditional and has
5185 precisely two successors, determine which of the edges is taken if
5186 the conditional is true and which is taken if the conditional is
5187 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5190 extract_true_false_edges_from_block (basic_block b
,
5194 edge e
= EDGE_SUCC (b
, 0);
5196 if (e
->flags
& EDGE_TRUE_VALUE
)
5199 *false_edge
= EDGE_SUCC (b
, 1);
5204 *true_edge
= EDGE_SUCC (b
, 1);
5208 struct tree_opt_pass pass_warn_function_return
=
5212 execute_warn_function_return
, /* execute */
5215 0, /* static_pass_number */
5217 PROP_cfg
, /* properties_required */
5218 0, /* properties_provided */
5219 0, /* properties_destroyed */
5220 0, /* todo_flags_start */
5221 0, /* todo_flags_finish */
5225 /* Emit noreturn warnings. */
5228 execute_warn_function_noreturn (void)
5230 if (warn_missing_noreturn
5231 && !TREE_THIS_VOLATILE (cfun
->decl
)
5232 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5233 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5234 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5235 "for attribute %<noreturn%>",
5239 struct tree_opt_pass pass_warn_function_noreturn
=
5243 execute_warn_function_noreturn
, /* execute */
5246 0, /* static_pass_number */
5248 PROP_cfg
, /* properties_required */
5249 0, /* properties_provided */
5250 0, /* properties_destroyed */
5251 0, /* todo_flags_start */
5252 0, /* todo_flags_finish */