1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
48 #include "tree-ssa-propagate.h"
49 #include "value-prof.h"
51 /* This file contains functions for building the Control Flow Graph (CFG)
52 for a function tree. */
54 /* Local declarations. */
56 /* Initial capacity for the basic block array. */
57 static const int initial_cfg_capacity
= 20;
59 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
60 which use a particular edge. The CASE_LABEL_EXPRs are chained together
61 via their TREE_CHAIN field, which we clear after we're done with the
62 hash table to prevent problems with duplication of SWITCH_EXPRs.
64 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
65 update the case vector in response to edge redirections.
67 Right now this table is set up and torn down at key points in the
68 compilation process. It would be nice if we could make the table
69 more persistent. The key is getting notification of changes to
70 the CFG (particularly edge removal, creation and redirection). */
72 struct edge_to_cases_elt
74 /* The edge itself. Necessary for hashing and equality tests. */
77 /* The case labels associated with this edge. We link these up via
78 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
79 when we destroy the hash table. This prevents problems when copying
84 static htab_t edge_to_cases
;
89 long num_merged_labels
;
92 static struct cfg_stats_d cfg_stats
;
94 /* Nonzero if we found a computed goto while building basic blocks. */
95 static bool found_computed_goto
;
97 /* Basic blocks and flowgraphs. */
98 static basic_block
create_bb (void *, void *, basic_block
);
99 static void make_blocks (tree
);
100 static void factor_computed_gotos (void);
103 static void make_edges (void);
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 unsigned int 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 *);
116 static inline void change_bb_for_stmt (tree t
, basic_block bb
);
118 /* Flowgraph optimization and cleanup. */
119 static void tree_merge_blocks (basic_block
, basic_block
);
120 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
121 static void remove_bb (basic_block
);
122 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
123 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
124 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
125 static tree
find_case_label_for_value (tree
, tree
);
128 init_empty_tree_cfg (void)
130 /* Initialize the basic block array. */
132 profile_status
= PROFILE_ABSENT
;
133 n_basic_blocks
= NUM_FIXED_BLOCKS
;
134 last_basic_block
= NUM_FIXED_BLOCKS
;
135 basic_block_info
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
136 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
,
137 initial_cfg_capacity
);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
141 VEC_safe_grow_cleared (basic_block
, gc
, label_to_block_map
,
142 initial_cfg_capacity
);
144 SET_BASIC_BLOCK (ENTRY_BLOCK
, ENTRY_BLOCK_PTR
);
145 SET_BASIC_BLOCK (EXIT_BLOCK
, EXIT_BLOCK_PTR
);
146 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
147 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
150 /*---------------------------------------------------------------------------
152 ---------------------------------------------------------------------------*/
154 /* Entry point to the CFG builder for trees. TP points to the list of
155 statements to be added to the flowgraph. */
158 build_tree_cfg (tree
*tp
)
160 /* Register specific tree functions. */
161 tree_register_cfg_hooks ();
163 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
165 init_empty_tree_cfg ();
167 found_computed_goto
= 0;
170 /* Computed gotos are hell to deal with, especially if there are
171 lots of them with a large number of destinations. So we factor
172 them to a common computed goto location before we build the
173 edge list. After we convert back to normal form, we will un-factor
174 the computed gotos since factoring introduces an unwanted jump. */
175 if (found_computed_goto
)
176 factor_computed_gotos ();
178 /* Make sure there is always at least one block, even if it's empty. */
179 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
180 create_empty_bb (ENTRY_BLOCK_PTR
);
182 /* Adjust the size of the array. */
183 if (VEC_length (basic_block
, basic_block_info
) < (size_t) n_basic_blocks
)
184 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, n_basic_blocks
);
186 /* To speed up statement iterator walks, we first purge dead labels. */
187 cleanup_dead_labels ();
189 /* Group case nodes to reduce the number of edges.
190 We do this after cleaning up dead labels because otherwise we miss
191 a lot of obvious case merging opportunities. */
192 group_case_labels ();
194 /* Create the edges of the flowgraph. */
197 /* Debugging dumps. */
199 /* Write the flowgraph to a VCG file. */
201 int local_dump_flags
;
202 FILE *vcg_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
205 tree_cfg2vcg (vcg_file
);
206 dump_end (TDI_vcg
, vcg_file
);
210 #ifdef ENABLE_CHECKING
214 /* Dump a textual representation of the flowgraph. */
216 dump_tree_cfg (dump_file
, dump_flags
);
220 execute_build_cfg (void)
222 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
226 struct tree_opt_pass pass_build_cfg
=
230 execute_build_cfg
, /* execute */
233 0, /* static_pass_number */
234 TV_TREE_CFG
, /* tv_id */
235 PROP_gimple_leh
, /* properties_required */
236 PROP_cfg
, /* properties_provided */
237 0, /* properties_destroyed */
238 0, /* todo_flags_start */
239 TODO_verify_stmts
, /* todo_flags_finish */
243 /* Search the CFG for any computed gotos. If found, factor them to a
244 common computed goto site. Also record the location of that site so
245 that we can un-factor the gotos after we have converted back to
249 factor_computed_gotos (void)
252 tree factored_label_decl
= NULL
;
254 tree factored_computed_goto_label
= NULL
;
255 tree factored_computed_goto
= NULL
;
257 /* We know there are one or more computed gotos in this function.
258 Examine the last statement in each basic block to see if the block
259 ends with a computed goto. */
263 block_stmt_iterator bsi
= bsi_last (bb
);
268 last
= bsi_stmt (bsi
);
270 /* Ignore the computed goto we create when we factor the original
272 if (last
== factored_computed_goto
)
275 /* If the last statement is a computed goto, factor it. */
276 if (computed_goto_p (last
))
280 /* The first time we find a computed goto we need to create
281 the factored goto block and the variable each original
282 computed goto will use for their goto destination. */
283 if (! factored_computed_goto
)
285 basic_block new_bb
= create_empty_bb (bb
);
286 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
288 /* Create the destination of the factored goto. Each original
289 computed goto will put its desired destination into this
290 variable and jump to the label we create immediately
292 var
= create_tmp_var (ptr_type_node
, "gotovar");
294 /* Build a label for the new block which will contain the
295 factored computed goto. */
296 factored_label_decl
= create_artificial_label ();
297 factored_computed_goto_label
298 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
299 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
302 /* Build our new computed goto. */
303 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
304 bsi_insert_after (&new_bsi
, factored_computed_goto
,
308 /* Copy the original computed goto's destination into VAR. */
309 assignment
= build2_gimple (GIMPLE_MODIFY_STMT
,
310 var
, GOTO_DESTINATION (last
));
311 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
313 /* And re-vector the computed goto to the new destination. */
314 GOTO_DESTINATION (last
) = factored_label_decl
;
320 /* Build a flowgraph for the statement_list STMT_LIST. */
323 make_blocks (tree stmt_list
)
325 tree_stmt_iterator i
= tsi_start (stmt_list
);
327 bool start_new_block
= true;
328 bool first_stmt_of_list
= true;
329 basic_block bb
= ENTRY_BLOCK_PTR
;
331 while (!tsi_end_p (i
))
338 /* If the statement starts a new basic block or if we have determined
339 in a previous pass that we need to create a new block for STMT, do
341 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
343 if (!first_stmt_of_list
)
344 stmt_list
= tsi_split_statement_list_before (&i
);
345 bb
= create_basic_block (stmt_list
, NULL
, bb
);
346 start_new_block
= false;
349 /* Now add STMT to BB and create the subgraphs for special statement
351 set_bb_for_stmt (stmt
, bb
);
353 if (computed_goto_p (stmt
))
354 found_computed_goto
= true;
356 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
358 if (stmt_ends_bb_p (stmt
))
359 start_new_block
= true;
362 first_stmt_of_list
= false;
367 /* Create and return a new empty basic block after bb AFTER. */
370 create_bb (void *h
, void *e
, basic_block after
)
376 /* Create and initialize a new basic block. Since alloc_block uses
377 ggc_alloc_cleared to allocate a basic block, we do not have to
378 clear the newly allocated basic block here. */
381 bb
->index
= last_basic_block
;
383 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
385 /* Add the new block to the linked list of blocks. */
386 link_block (bb
, after
);
388 /* Grow the basic block array if needed. */
389 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
391 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
392 VEC_safe_grow_cleared (basic_block
, gc
, basic_block_info
, new_size
);
395 /* Add the newly created block to the array. */
396 SET_BASIC_BLOCK (last_basic_block
, bb
);
405 /*---------------------------------------------------------------------------
407 ---------------------------------------------------------------------------*/
409 /* Fold COND_EXPR_COND of each COND_EXPR. */
412 fold_cond_expr_cond (void)
418 tree stmt
= last_stmt (bb
);
421 && TREE_CODE (stmt
) == COND_EXPR
)
423 tree cond
= fold (COND_EXPR_COND (stmt
));
424 if (integer_zerop (cond
))
425 COND_EXPR_COND (stmt
) = boolean_false_node
;
426 else if (integer_onep (cond
))
427 COND_EXPR_COND (stmt
) = boolean_true_node
;
432 /* Join all the blocks in the flowgraph. */
438 struct omp_region
*cur_region
= NULL
;
440 /* Create an edge from entry to the first block with executable
442 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
444 /* Traverse the basic block array placing edges. */
447 tree last
= last_stmt (bb
);
452 enum tree_code code
= TREE_CODE (last
);
456 make_goto_expr_edges (bb
);
460 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
464 make_cond_expr_edges (bb
);
468 make_switch_expr_edges (bb
);
472 make_eh_edges (last
);
477 /* If this function receives a nonlocal goto, then we need to
478 make edges from this call site to all the nonlocal goto
480 if (tree_can_make_abnormal_goto (last
))
481 make_abnormal_goto_edges (bb
, true);
483 /* If this statement has reachable exception handlers, then
484 create abnormal edges to them. */
485 make_eh_edges (last
);
487 /* Some calls are known not to return. */
488 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
494 case GIMPLE_MODIFY_STMT
:
495 if (is_ctrl_altering_stmt (last
))
497 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
498 the CALL_EXPR may have an abnormal edge. Search the RHS
499 for this case and create any required edges. */
500 if (tree_can_make_abnormal_goto (last
))
501 make_abnormal_goto_edges (bb
, true);
503 make_eh_edges (last
);
515 cur_region
= new_omp_region (bb
, code
, cur_region
);
520 cur_region
= new_omp_region (bb
, code
, cur_region
);
525 /* In the case of an OMP_SECTION, the edge will go somewhere
526 other than the next block. This will be created later. */
527 cur_region
->exit
= bb
;
528 fallthru
= cur_region
->type
!= OMP_SECTION
;
529 cur_region
= cur_region
->outer
;
533 cur_region
->cont
= bb
;
534 switch (cur_region
->type
)
537 /* ??? Technically there should be a some sort of loopback
538 edge here, but it goes to a block that doesn't exist yet,
539 and without it, updating the ssa form would be a real
540 bear. Fortunately, we don't yet do ssa before expanding
545 /* Wire up the edges into and out of the nested sections. */
546 /* ??? Similarly wrt loopback. */
548 struct omp_region
*i
;
549 for (i
= cur_region
->inner
; i
; i
= i
->next
)
551 gcc_assert (i
->type
== OMP_SECTION
);
552 make_edge (cur_region
->entry
, i
->entry
, 0);
553 make_edge (i
->exit
, bb
, EDGE_FALLTHRU
);
565 gcc_assert (!stmt_ends_bb_p (last
));
573 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
579 /* Fold COND_EXPR_COND of each COND_EXPR. */
580 fold_cond_expr_cond ();
582 /* Clean up the graph and warn for unreachable code. */
587 /* Create the edges for a COND_EXPR starting at block BB.
588 At this point, both clauses must contain only simple gotos. */
591 make_cond_expr_edges (basic_block bb
)
593 tree entry
= last_stmt (bb
);
594 basic_block then_bb
, else_bb
;
595 tree then_label
, else_label
;
599 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
601 /* Entry basic blocks for each component. */
602 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
603 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
604 then_bb
= label_to_block (then_label
);
605 else_bb
= label_to_block (else_label
);
607 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
608 #ifdef USE_MAPPED_LOCATION
609 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
611 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
613 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
616 #ifdef USE_MAPPED_LOCATION
617 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
619 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
624 /* Hashing routine for EDGE_TO_CASES. */
627 edge_to_cases_hash (const void *p
)
629 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
631 /* Hash on the edge itself (which is a pointer). */
632 return htab_hash_pointer (e
);
635 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
636 for equality is just a pointer comparison. */
639 edge_to_cases_eq (const void *p1
, const void *p2
)
641 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
642 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
647 /* Called for each element in the hash table (P) as we delete the
648 edge to cases hash table.
650 Clear all the TREE_CHAINs to prevent problems with copying of
651 SWITCH_EXPRs and structure sharing rules, then free the hash table
655 edge_to_cases_cleanup (void *p
)
657 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
660 for (t
= elt
->case_labels
; t
; t
= next
)
662 next
= TREE_CHAIN (t
);
663 TREE_CHAIN (t
) = NULL
;
668 /* Start recording information mapping edges to case labels. */
671 start_recording_case_labels (void)
673 gcc_assert (edge_to_cases
== NULL
);
675 edge_to_cases
= htab_create (37,
678 edge_to_cases_cleanup
);
681 /* Return nonzero if we are recording information for case labels. */
684 recording_case_labels_p (void)
686 return (edge_to_cases
!= NULL
);
689 /* Stop recording information mapping edges to case labels and
690 remove any information we have recorded. */
692 end_recording_case_labels (void)
694 htab_delete (edge_to_cases
);
695 edge_to_cases
= NULL
;
698 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
701 record_switch_edge (edge e
, tree case_label
)
703 struct edge_to_cases_elt
*elt
;
706 /* Build a hash table element so we can see if E is already
708 elt
= XNEW (struct edge_to_cases_elt
);
710 elt
->case_labels
= case_label
;
712 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
716 /* E was not in the hash table. Install E into the hash table. */
721 /* E was already in the hash table. Free ELT as we do not need it
725 /* Get the entry stored in the hash table. */
726 elt
= (struct edge_to_cases_elt
*) *slot
;
728 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
729 TREE_CHAIN (case_label
) = elt
->case_labels
;
730 elt
->case_labels
= case_label
;
734 /* If we are inside a {start,end}_recording_cases block, then return
735 a chain of CASE_LABEL_EXPRs from T which reference E.
737 Otherwise return NULL. */
740 get_cases_for_edge (edge e
, tree t
)
742 struct edge_to_cases_elt elt
, *elt_p
;
747 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
748 chains available. Return NULL so the caller can detect this case. */
749 if (!recording_case_labels_p ())
754 elt
.case_labels
= NULL
;
755 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
759 elt_p
= (struct edge_to_cases_elt
*)*slot
;
760 return elt_p
->case_labels
;
763 /* If we did not find E in the hash table, then this must be the first
764 time we have been queried for information about E & T. Add all the
765 elements from T to the hash table then perform the query again. */
767 vec
= SWITCH_LABELS (t
);
768 n
= TREE_VEC_LENGTH (vec
);
769 for (i
= 0; i
< n
; i
++)
771 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
772 basic_block label_bb
= label_to_block (lab
);
773 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
778 /* Create the edges for a SWITCH_EXPR starting at block BB.
779 At this point, the switch body has been lowered and the
780 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
783 make_switch_expr_edges (basic_block bb
)
785 tree entry
= last_stmt (bb
);
789 vec
= SWITCH_LABELS (entry
);
790 n
= TREE_VEC_LENGTH (vec
);
792 for (i
= 0; i
< n
; ++i
)
794 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
795 basic_block label_bb
= label_to_block (lab
);
796 make_edge (bb
, label_bb
, 0);
801 /* Return the basic block holding label DEST. */
804 label_to_block_fn (struct function
*ifun
, tree dest
)
806 int uid
= LABEL_DECL_UID (dest
);
808 /* We would die hard when faced by an undefined label. Emit a label to
809 the very first basic block. This will hopefully make even the dataflow
810 and undefined variable warnings quite right. */
811 if ((errorcount
|| sorrycount
) && uid
< 0)
813 block_stmt_iterator bsi
=
814 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
817 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
818 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
819 uid
= LABEL_DECL_UID (dest
);
821 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
822 <= (unsigned int) uid
)
824 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
827 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
828 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
831 make_abnormal_goto_edges (basic_block bb
, bool for_call
)
833 basic_block target_bb
;
834 block_stmt_iterator bsi
;
836 FOR_EACH_BB (target_bb
)
837 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
839 tree target
= bsi_stmt (bsi
);
841 if (TREE_CODE (target
) != LABEL_EXPR
)
844 target
= LABEL_EXPR_LABEL (target
);
846 /* Make an edge to every label block that has been marked as a
847 potential target for a computed goto or a non-local goto. */
848 if ((FORCED_LABEL (target
) && !for_call
)
849 || (DECL_NONLOCAL (target
) && for_call
))
851 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
857 /* Create edges for a goto statement at block BB. */
860 make_goto_expr_edges (basic_block bb
)
862 block_stmt_iterator last
= bsi_last (bb
);
863 tree goto_t
= bsi_stmt (last
);
865 /* A simple GOTO creates normal edges. */
866 if (simple_goto_p (goto_t
))
868 tree dest
= GOTO_DESTINATION (goto_t
);
869 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
870 #ifdef USE_MAPPED_LOCATION
871 e
->goto_locus
= EXPR_LOCATION (goto_t
);
873 e
->goto_locus
= EXPR_LOCUS (goto_t
);
875 bsi_remove (&last
, true);
879 /* A computed GOTO creates abnormal edges. */
880 make_abnormal_goto_edges (bb
, false);
884 /*---------------------------------------------------------------------------
886 ---------------------------------------------------------------------------*/
888 /* Cleanup useless labels in basic blocks. This is something we wish
889 to do early because it allows us to group case labels before creating
890 the edges for the CFG, and it speeds up block statement iterators in
892 We only run this pass once, running it more than once is probably not
895 /* A map from basic block index to the leading label of that block. */
896 static tree
*label_for_bb
;
898 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
900 update_eh_label (struct eh_region
*region
)
902 tree old_label
= get_eh_region_tree_label (region
);
906 basic_block bb
= label_to_block (old_label
);
908 /* ??? After optimizing, there may be EH regions with labels
909 that have already been removed from the function body, so
910 there is no basic block for them. */
914 new_label
= label_for_bb
[bb
->index
];
915 set_eh_region_tree_label (region
, new_label
);
919 /* Given LABEL return the first label in the same basic block. */
921 main_block_label (tree label
)
923 basic_block bb
= label_to_block (label
);
925 /* label_to_block possibly inserted undefined label into the chain. */
926 if (!label_for_bb
[bb
->index
])
927 label_for_bb
[bb
->index
] = label
;
928 return label_for_bb
[bb
->index
];
931 /* Cleanup redundant labels. This is a three-step process:
932 1) Find the leading label for each block.
933 2) Redirect all references to labels to the leading labels.
934 3) Cleanup all useless labels. */
937 cleanup_dead_labels (void)
940 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
942 /* Find a suitable label for each block. We use the first user-defined
943 label if there is one, or otherwise just the first label we see. */
946 block_stmt_iterator i
;
948 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
950 tree label
, stmt
= bsi_stmt (i
);
952 if (TREE_CODE (stmt
) != LABEL_EXPR
)
955 label
= LABEL_EXPR_LABEL (stmt
);
957 /* If we have not yet seen a label for the current block,
958 remember this one and see if there are more labels. */
959 if (! label_for_bb
[bb
->index
])
961 label_for_bb
[bb
->index
] = label
;
965 /* If we did see a label for the current block already, but it
966 is an artificially created label, replace it if the current
967 label is a user defined label. */
968 if (! DECL_ARTIFICIAL (label
)
969 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
971 label_for_bb
[bb
->index
] = label
;
977 /* Now redirect all jumps/branches to the selected label.
978 First do so for each block ending in a control statement. */
981 tree stmt
= last_stmt (bb
);
985 switch (TREE_CODE (stmt
))
989 tree true_branch
, false_branch
;
991 true_branch
= COND_EXPR_THEN (stmt
);
992 false_branch
= COND_EXPR_ELSE (stmt
);
994 GOTO_DESTINATION (true_branch
)
995 = main_block_label (GOTO_DESTINATION (true_branch
));
996 GOTO_DESTINATION (false_branch
)
997 = main_block_label (GOTO_DESTINATION (false_branch
));
1005 tree vec
= SWITCH_LABELS (stmt
);
1006 size_t n
= TREE_VEC_LENGTH (vec
);
1008 /* Replace all destination labels. */
1009 for (i
= 0; i
< n
; ++i
)
1011 tree elt
= TREE_VEC_ELT (vec
, i
);
1012 tree label
= main_block_label (CASE_LABEL (elt
));
1013 CASE_LABEL (elt
) = label
;
1018 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1019 remove them until after we've created the CFG edges. */
1021 if (! computed_goto_p (stmt
))
1023 GOTO_DESTINATION (stmt
)
1024 = main_block_label (GOTO_DESTINATION (stmt
));
1033 for_each_eh_region (update_eh_label
);
1035 /* Finally, purge dead labels. All user-defined labels and labels that
1036 can be the target of non-local gotos and labels which have their
1037 address taken are preserved. */
1040 block_stmt_iterator i
;
1041 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1043 if (! label_for_this_bb
)
1046 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1048 tree label
, stmt
= bsi_stmt (i
);
1050 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1053 label
= LABEL_EXPR_LABEL (stmt
);
1055 if (label
== label_for_this_bb
1056 || ! DECL_ARTIFICIAL (label
)
1057 || DECL_NONLOCAL (label
)
1058 || FORCED_LABEL (label
))
1061 bsi_remove (&i
, true);
1065 free (label_for_bb
);
1068 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1069 and scan the sorted vector of cases. Combine the ones jumping to the
1071 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1074 group_case_labels (void)
1080 tree stmt
= last_stmt (bb
);
1081 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1083 tree labels
= SWITCH_LABELS (stmt
);
1084 int old_size
= TREE_VEC_LENGTH (labels
);
1085 int i
, j
, new_size
= old_size
;
1086 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1089 /* The default label is always the last case in a switch
1090 statement after gimplification. */
1091 default_label
= CASE_LABEL (default_case
);
1093 /* Look for possible opportunities to merge cases.
1094 Ignore the last element of the label vector because it
1095 must be the default case. */
1097 while (i
< old_size
- 1)
1099 tree base_case
, base_label
, base_high
;
1100 base_case
= TREE_VEC_ELT (labels
, i
);
1102 gcc_assert (base_case
);
1103 base_label
= CASE_LABEL (base_case
);
1105 /* Discard cases that have the same destination as the
1107 if (base_label
== default_label
)
1109 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1115 base_high
= CASE_HIGH (base_case
) ?
1116 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1118 /* Try to merge case labels. Break out when we reach the end
1119 of the label vector or when we cannot merge the next case
1120 label with the current one. */
1121 while (i
< old_size
- 1)
1123 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1124 tree merge_label
= CASE_LABEL (merge_case
);
1125 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1126 integer_one_node
, 1);
1128 /* Merge the cases if they jump to the same place,
1129 and their ranges are consecutive. */
1130 if (merge_label
== base_label
1131 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1133 base_high
= CASE_HIGH (merge_case
) ?
1134 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1135 CASE_HIGH (base_case
) = base_high
;
1136 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1145 /* Compress the case labels in the label vector, and adjust the
1146 length of the vector. */
1147 for (i
= 0, j
= 0; i
< new_size
; i
++)
1149 while (! TREE_VEC_ELT (labels
, j
))
1151 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1153 TREE_VEC_LENGTH (labels
) = new_size
;
1158 /* Checks whether we can merge block B into block A. */
1161 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1164 block_stmt_iterator bsi
;
1167 if (!single_succ_p (a
))
1170 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1173 if (single_succ (a
) != b
)
1176 if (!single_pred_p (b
))
1179 if (b
== EXIT_BLOCK_PTR
)
1182 /* If A ends by a statement causing exceptions or something similar, we
1183 cannot merge the blocks. */
1184 stmt
= last_stmt (a
);
1185 if (stmt
&& stmt_ends_bb_p (stmt
))
1188 /* Do not allow a block with only a non-local label to be merged. */
1189 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1190 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1193 /* It must be possible to eliminate all phi nodes in B. If ssa form
1194 is not up-to-date, we cannot eliminate any phis; however, if only
1195 some symbols as whole are marked for renaming, this is not a problem,
1196 as phi nodes for those symbols are irrelevant in updating anyway. */
1197 phi
= phi_nodes (b
);
1200 if (name_mappings_registered_p ())
1203 for (; phi
; phi
= PHI_CHAIN (phi
))
1204 if (!is_gimple_reg (PHI_RESULT (phi
))
1205 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1209 /* Do not remove user labels. */
1210 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1212 stmt
= bsi_stmt (bsi
);
1213 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1215 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1219 /* Protect the loop latches. */
1221 && b
->loop_father
->latch
== b
)
1227 /* Replaces all uses of NAME by VAL. */
1230 replace_uses_by (tree name
, tree val
)
1232 imm_use_iterator imm_iter
;
1237 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, name
)
1239 if (TREE_CODE (stmt
) != PHI_NODE
)
1240 push_stmt_changes (&stmt
);
1242 FOR_EACH_IMM_USE_ON_STMT (use
, imm_iter
)
1244 replace_exp (use
, val
);
1246 if (TREE_CODE (stmt
) == PHI_NODE
)
1248 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1249 if (e
->flags
& EDGE_ABNORMAL
)
1251 /* This can only occur for virtual operands, since
1252 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1253 would prevent replacement. */
1254 gcc_assert (!is_gimple_reg (name
));
1255 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1260 if (TREE_CODE (stmt
) != PHI_NODE
)
1264 fold_stmt_inplace (stmt
);
1266 /* FIXME. This should go in pop_stmt_changes. */
1267 rhs
= get_rhs (stmt
);
1268 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1269 recompute_tree_invariant_for_addr_expr (rhs
);
1271 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1273 pop_stmt_changes (&stmt
);
1277 gcc_assert (zero_imm_uses_p (name
));
1279 /* Also update the trees stored in loop structures. */
1285 FOR_EACH_LOOP (li
, loop
, 0)
1287 substitute_in_loop_info (loop
, name
, val
);
1292 /* Merge block B into block A. */
1295 tree_merge_blocks (basic_block a
, basic_block b
)
1297 block_stmt_iterator bsi
;
1298 tree_stmt_iterator last
;
1302 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1304 /* Remove all single-valued PHI nodes from block B of the form
1305 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1307 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1309 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1311 bool may_replace_uses
= may_propagate_copy (def
, use
);
1313 /* In case we have loops to care about, do not propagate arguments of
1314 loop closed ssa phi nodes. */
1316 && is_gimple_reg (def
)
1317 && TREE_CODE (use
) == SSA_NAME
1318 && a
->loop_father
!= b
->loop_father
)
1319 may_replace_uses
= false;
1321 if (!may_replace_uses
)
1323 gcc_assert (is_gimple_reg (def
));
1325 /* Note that just emitting the copies is fine -- there is no problem
1326 with ordering of phi nodes. This is because A is the single
1327 predecessor of B, therefore results of the phi nodes cannot
1328 appear as arguments of the phi nodes. */
1329 copy
= build2_gimple (GIMPLE_MODIFY_STMT
, def
, use
);
1330 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1331 SSA_NAME_DEF_STMT (def
) = copy
;
1332 remove_phi_node (phi
, NULL
, false);
1336 replace_uses_by (def
, use
);
1337 remove_phi_node (phi
, NULL
, true);
1341 /* Ensure that B follows A. */
1342 move_block_after (b
, a
);
1344 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1345 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1347 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1348 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1350 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1352 tree label
= bsi_stmt (bsi
);
1354 bsi_remove (&bsi
, false);
1355 /* Now that we can thread computed gotos, we might have
1356 a situation where we have a forced label in block B
1357 However, the label at the start of block B might still be
1358 used in other ways (think about the runtime checking for
1359 Fortran assigned gotos). So we can not just delete the
1360 label. Instead we move the label to the start of block A. */
1361 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1363 block_stmt_iterator dest_bsi
= bsi_start (a
);
1364 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1369 change_bb_for_stmt (bsi_stmt (bsi
), a
);
1374 /* Merge the chains. */
1375 last
= tsi_last (a
->stmt_list
);
1376 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1377 b
->stmt_list
= NULL
;
1381 /* Return the one of two successors of BB that is not reachable by a
1382 reached by a complex edge, if there is one. Else, return BB. We use
1383 this in optimizations that use post-dominators for their heuristics,
1384 to catch the cases in C++ where function calls are involved. */
1387 single_noncomplex_succ (basic_block bb
)
1390 if (EDGE_COUNT (bb
->succs
) != 2)
1393 e0
= EDGE_SUCC (bb
, 0);
1394 e1
= EDGE_SUCC (bb
, 1);
1395 if (e0
->flags
& EDGE_COMPLEX
)
1397 if (e1
->flags
& EDGE_COMPLEX
)
1404 /* Walk the function tree removing unnecessary statements.
1406 * Empty statement nodes are removed
1408 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1410 * Unnecessary COND_EXPRs are removed
1412 * Some unnecessary BIND_EXPRs are removed
1414 Clearly more work could be done. The trick is doing the analysis
1415 and removal fast enough to be a net improvement in compile times.
1417 Note that when we remove a control structure such as a COND_EXPR
1418 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1419 to ensure we eliminate all the useless code. */
1430 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1433 remove_useless_stmts_warn_notreached (tree stmt
)
1435 if (EXPR_HAS_LOCATION (stmt
))
1437 location_t loc
= EXPR_LOCATION (stmt
);
1438 if (LOCATION_LINE (loc
) > 0)
1440 warning (0, "%Hwill never be executed", &loc
);
1445 switch (TREE_CODE (stmt
))
1447 case STATEMENT_LIST
:
1449 tree_stmt_iterator i
;
1450 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1451 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1457 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1459 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1461 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1465 case TRY_FINALLY_EXPR
:
1466 case TRY_CATCH_EXPR
:
1467 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1469 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1474 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1475 case EH_FILTER_EXPR
:
1476 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1478 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1481 /* Not a live container. */
1489 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1491 tree then_clause
, else_clause
, cond
;
1492 bool save_has_label
, then_has_label
, else_has_label
;
1494 save_has_label
= data
->has_label
;
1495 data
->has_label
= false;
1496 data
->last_goto
= NULL
;
1498 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1500 then_has_label
= data
->has_label
;
1501 data
->has_label
= false;
1502 data
->last_goto
= NULL
;
1504 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1506 else_has_label
= data
->has_label
;
1507 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1509 then_clause
= COND_EXPR_THEN (*stmt_p
);
1510 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1511 cond
= fold (COND_EXPR_COND (*stmt_p
));
1513 /* If neither arm does anything at all, we can remove the whole IF. */
1514 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1516 *stmt_p
= build_empty_stmt ();
1517 data
->repeat
= true;
1520 /* If there are no reachable statements in an arm, then we can
1521 zap the entire conditional. */
1522 else if (integer_nonzerop (cond
) && !else_has_label
)
1524 if (warn_notreached
)
1525 remove_useless_stmts_warn_notreached (else_clause
);
1526 *stmt_p
= then_clause
;
1527 data
->repeat
= true;
1529 else if (integer_zerop (cond
) && !then_has_label
)
1531 if (warn_notreached
)
1532 remove_useless_stmts_warn_notreached (then_clause
);
1533 *stmt_p
= else_clause
;
1534 data
->repeat
= true;
1537 /* Check a couple of simple things on then/else with single stmts. */
1540 tree then_stmt
= expr_only (then_clause
);
1541 tree else_stmt
= expr_only (else_clause
);
1543 /* Notice branches to a common destination. */
1544 if (then_stmt
&& else_stmt
1545 && TREE_CODE (then_stmt
) == GOTO_EXPR
1546 && TREE_CODE (else_stmt
) == GOTO_EXPR
1547 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1549 *stmt_p
= then_stmt
;
1550 data
->repeat
= true;
1553 /* If the THEN/ELSE clause merely assigns a value to a variable or
1554 parameter which is already known to contain that value, then
1555 remove the useless THEN/ELSE clause. */
1556 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1559 && TREE_CODE (else_stmt
) == GIMPLE_MODIFY_STMT
1560 && GIMPLE_STMT_OPERAND (else_stmt
, 0) == cond
1561 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt
, 1)))
1562 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1564 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1565 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1566 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1567 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1569 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1570 ? then_stmt
: else_stmt
);
1571 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1572 ? &COND_EXPR_THEN (*stmt_p
)
1573 : &COND_EXPR_ELSE (*stmt_p
));
1576 && TREE_CODE (stmt
) == GIMPLE_MODIFY_STMT
1577 && GIMPLE_STMT_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1578 && GIMPLE_STMT_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1579 *location
= alloc_stmt_list ();
1583 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1584 would be re-introduced during lowering. */
1585 data
->last_goto
= NULL
;
1590 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1592 bool save_may_branch
, save_may_throw
;
1593 bool this_may_branch
, this_may_throw
;
1595 /* Collect may_branch and may_throw information for the body only. */
1596 save_may_branch
= data
->may_branch
;
1597 save_may_throw
= data
->may_throw
;
1598 data
->may_branch
= false;
1599 data
->may_throw
= false;
1600 data
->last_goto
= NULL
;
1602 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1604 this_may_branch
= data
->may_branch
;
1605 this_may_throw
= data
->may_throw
;
1606 data
->may_branch
|= save_may_branch
;
1607 data
->may_throw
|= save_may_throw
;
1608 data
->last_goto
= NULL
;
1610 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1612 /* If the body is empty, then we can emit the FINALLY block without
1613 the enclosing TRY_FINALLY_EXPR. */
1614 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1616 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1617 data
->repeat
= true;
1620 /* If the handler is empty, then we can emit the TRY block without
1621 the enclosing TRY_FINALLY_EXPR. */
1622 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1624 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1625 data
->repeat
= true;
1628 /* If the body neither throws, nor branches, then we can safely
1629 string the TRY and FINALLY blocks together. */
1630 else if (!this_may_branch
&& !this_may_throw
)
1632 tree stmt
= *stmt_p
;
1633 *stmt_p
= TREE_OPERAND (stmt
, 0);
1634 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1635 data
->repeat
= true;
1641 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1643 bool save_may_throw
, this_may_throw
;
1644 tree_stmt_iterator i
;
1647 /* Collect may_throw information for the body only. */
1648 save_may_throw
= data
->may_throw
;
1649 data
->may_throw
= false;
1650 data
->last_goto
= NULL
;
1652 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1654 this_may_throw
= data
->may_throw
;
1655 data
->may_throw
= save_may_throw
;
1657 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1658 if (!this_may_throw
)
1660 if (warn_notreached
)
1661 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1662 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1663 data
->repeat
= true;
1667 /* Process the catch clause specially. We may be able to tell that
1668 no exceptions propagate past this point. */
1670 this_may_throw
= true;
1671 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1672 stmt
= tsi_stmt (i
);
1673 data
->last_goto
= NULL
;
1675 switch (TREE_CODE (stmt
))
1678 for (; !tsi_end_p (i
); tsi_next (&i
))
1680 stmt
= tsi_stmt (i
);
1681 /* If we catch all exceptions, then the body does not
1682 propagate exceptions past this point. */
1683 if (CATCH_TYPES (stmt
) == NULL
)
1684 this_may_throw
= false;
1685 data
->last_goto
= NULL
;
1686 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1690 case EH_FILTER_EXPR
:
1691 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1692 this_may_throw
= false;
1693 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1694 this_may_throw
= false;
1695 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1699 /* Otherwise this is a cleanup. */
1700 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1702 /* If the cleanup is empty, then we can emit the TRY block without
1703 the enclosing TRY_CATCH_EXPR. */
1704 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1706 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1707 data
->repeat
= true;
1711 data
->may_throw
|= this_may_throw
;
1716 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1720 /* First remove anything underneath the BIND_EXPR. */
1721 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1723 /* If the BIND_EXPR has no variables, then we can pull everything
1724 up one level and remove the BIND_EXPR, unless this is the toplevel
1725 BIND_EXPR for the current function or an inlined function.
1727 When this situation occurs we will want to apply this
1728 optimization again. */
1729 block
= BIND_EXPR_BLOCK (*stmt_p
);
1730 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1731 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1733 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1734 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1737 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1738 data
->repeat
= true;
1744 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1746 tree dest
= GOTO_DESTINATION (*stmt_p
);
1748 data
->may_branch
= true;
1749 data
->last_goto
= NULL
;
1751 /* Record the last goto expr, so that we can delete it if unnecessary. */
1752 if (TREE_CODE (dest
) == LABEL_DECL
)
1753 data
->last_goto
= stmt_p
;
1758 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1760 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1762 data
->has_label
= true;
1764 /* We do want to jump across non-local label receiver code. */
1765 if (DECL_NONLOCAL (label
))
1766 data
->last_goto
= NULL
;
1768 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1770 *data
->last_goto
= build_empty_stmt ();
1771 data
->repeat
= true;
1774 /* ??? Add something here to delete unused labels. */
1778 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1779 decl. This allows us to eliminate redundant or useless
1780 calls to "const" functions.
1782 Gimplifier already does the same operation, but we may notice functions
1783 being const and pure once their calls has been gimplified, so we need
1784 to update the flag. */
1787 update_call_expr_flags (tree call
)
1789 tree decl
= get_callee_fndecl (call
);
1792 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1793 TREE_SIDE_EFFECTS (call
) = 0;
1794 if (TREE_NOTHROW (decl
))
1795 TREE_NOTHROW (call
) = 1;
1799 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1802 notice_special_calls (tree t
)
1804 int flags
= call_expr_flags (t
);
1806 if (flags
& ECF_MAY_BE_ALLOCA
)
1807 current_function_calls_alloca
= true;
1808 if (flags
& ECF_RETURNS_TWICE
)
1809 current_function_calls_setjmp
= true;
1813 /* Clear flags set by notice_special_calls. Used by dead code removal
1814 to update the flags. */
1817 clear_special_calls (void)
1819 current_function_calls_alloca
= false;
1820 current_function_calls_setjmp
= false;
1825 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1829 switch (TREE_CODE (t
))
1832 remove_useless_stmts_cond (tp
, data
);
1835 case TRY_FINALLY_EXPR
:
1836 remove_useless_stmts_tf (tp
, data
);
1839 case TRY_CATCH_EXPR
:
1840 remove_useless_stmts_tc (tp
, data
);
1844 remove_useless_stmts_bind (tp
, data
);
1848 remove_useless_stmts_goto (tp
, data
);
1852 remove_useless_stmts_label (tp
, data
);
1857 data
->last_goto
= NULL
;
1858 data
->may_branch
= true;
1863 data
->last_goto
= NULL
;
1864 notice_special_calls (t
);
1865 update_call_expr_flags (t
);
1866 if (tree_could_throw_p (t
))
1867 data
->may_throw
= true;
1873 case GIMPLE_MODIFY_STMT
:
1874 data
->last_goto
= NULL
;
1876 op
= get_call_expr_in (t
);
1879 update_call_expr_flags (op
);
1880 notice_special_calls (op
);
1882 if (tree_could_throw_p (t
))
1883 data
->may_throw
= true;
1886 case STATEMENT_LIST
:
1888 tree_stmt_iterator i
= tsi_start (t
);
1889 while (!tsi_end_p (i
))
1892 if (IS_EMPTY_STMT (t
))
1898 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1901 if (TREE_CODE (t
) == STATEMENT_LIST
)
1903 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1913 data
->last_goto
= NULL
;
1917 data
->last_goto
= NULL
;
1923 remove_useless_stmts (void)
1925 struct rus_data data
;
1927 clear_special_calls ();
1931 memset (&data
, 0, sizeof (data
));
1932 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1934 while (data
.repeat
);
1939 struct tree_opt_pass pass_remove_useless_stmts
=
1941 "useless", /* name */
1943 remove_useless_stmts
, /* execute */
1946 0, /* static_pass_number */
1948 PROP_gimple_any
, /* properties_required */
1949 0, /* properties_provided */
1950 0, /* properties_destroyed */
1951 0, /* todo_flags_start */
1952 TODO_dump_func
, /* todo_flags_finish */
1956 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1959 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1963 /* Since this block is no longer reachable, we can just delete all
1964 of its PHI nodes. */
1965 phi
= phi_nodes (bb
);
1968 tree next
= PHI_CHAIN (phi
);
1969 remove_phi_node (phi
, NULL_TREE
, true);
1973 /* Remove edges to BB's successors. */
1974 while (EDGE_COUNT (bb
->succs
) > 0)
1975 remove_edge (EDGE_SUCC (bb
, 0));
1979 /* Remove statements of basic block BB. */
1982 remove_bb (basic_block bb
)
1984 block_stmt_iterator i
;
1985 #ifdef USE_MAPPED_LOCATION
1986 source_location loc
= UNKNOWN_LOCATION
;
1988 source_locus loc
= 0;
1993 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1994 if (dump_flags
& TDF_DETAILS
)
1996 dump_bb (bb
, dump_file
, 0);
1997 fprintf (dump_file
, "\n");
2003 struct loop
*loop
= bb
->loop_father
;
2005 /* If a loop gets removed, clean up the information associated
2007 if (loop
->latch
== bb
2008 || loop
->header
== bb
)
2009 free_numbers_of_iterations_estimates_loop (loop
);
2012 /* Remove all the instructions in the block. */
2013 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2015 tree stmt
= bsi_stmt (i
);
2016 if (TREE_CODE (stmt
) == LABEL_EXPR
2017 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2018 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2021 block_stmt_iterator new_bsi
;
2023 /* A non-reachable non-local label may still be referenced.
2024 But it no longer needs to carry the extra semantics of
2026 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2028 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2029 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2032 new_bb
= bb
->prev_bb
;
2033 new_bsi
= bsi_start (new_bb
);
2034 bsi_remove (&i
, false);
2035 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2039 /* Release SSA definitions if we are in SSA. Note that we
2040 may be called when not in SSA. For example,
2041 final_cleanup calls this function via
2042 cleanup_tree_cfg. */
2043 if (gimple_in_ssa_p (cfun
))
2044 release_defs (stmt
);
2046 bsi_remove (&i
, true);
2049 /* Don't warn for removed gotos. Gotos are often removed due to
2050 jump threading, thus resulting in bogus warnings. Not great,
2051 since this way we lose warnings for gotos in the original
2052 program that are indeed unreachable. */
2053 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2055 #ifdef USE_MAPPED_LOCATION
2056 if (EXPR_HAS_LOCATION (stmt
))
2057 loc
= EXPR_LOCATION (stmt
);
2060 t
= EXPR_LOCUS (stmt
);
2061 if (t
&& LOCATION_LINE (*t
) > 0)
2067 /* If requested, give a warning that the first statement in the
2068 block is unreachable. We walk statements backwards in the
2069 loop above, so the last statement we process is the first statement
2071 #ifdef USE_MAPPED_LOCATION
2072 if (loc
> BUILTINS_LOCATION
)
2073 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2076 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2079 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2083 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2084 predicate VAL, return the edge that will be taken out of the block.
2085 If VAL does not match a unique edge, NULL is returned. */
2088 find_taken_edge (basic_block bb
, tree val
)
2092 stmt
= last_stmt (bb
);
2095 gcc_assert (is_ctrl_stmt (stmt
));
2098 if (! is_gimple_min_invariant (val
))
2101 if (TREE_CODE (stmt
) == COND_EXPR
)
2102 return find_taken_edge_cond_expr (bb
, val
);
2104 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2105 return find_taken_edge_switch_expr (bb
, val
);
2107 if (computed_goto_p (stmt
))
2108 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2113 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2114 statement, determine which of the outgoing edges will be taken out of the
2115 block. Return NULL if either edge may be taken. */
2118 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2123 dest
= label_to_block (val
);
2126 e
= find_edge (bb
, dest
);
2127 gcc_assert (e
!= NULL
);
2133 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2134 statement, determine which of the two edges will be taken out of the
2135 block. Return NULL if either edge may be taken. */
2138 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2140 edge true_edge
, false_edge
;
2142 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2144 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2145 return (integer_zerop (val
) ? false_edge
: true_edge
);
2148 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2149 statement, determine which edge will be taken out of the block. Return
2150 NULL if any edge may be taken. */
2153 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2155 tree switch_expr
, taken_case
;
2156 basic_block dest_bb
;
2159 switch_expr
= last_stmt (bb
);
2160 taken_case
= find_case_label_for_value (switch_expr
, val
);
2161 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2163 e
= find_edge (bb
, dest_bb
);
2169 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2170 We can make optimal use here of the fact that the case labels are
2171 sorted: We can do a binary search for a case matching VAL. */
2174 find_case_label_for_value (tree switch_expr
, tree val
)
2176 tree vec
= SWITCH_LABELS (switch_expr
);
2177 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2178 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2180 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2182 size_t i
= (high
+ low
) / 2;
2183 tree t
= TREE_VEC_ELT (vec
, i
);
2186 /* Cache the result of comparing CASE_LOW and val. */
2187 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2194 if (CASE_HIGH (t
) == NULL
)
2196 /* A singe-valued case label. */
2202 /* A case range. We can only handle integer ranges. */
2203 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2208 return default_case
;
2214 /*---------------------------------------------------------------------------
2216 ---------------------------------------------------------------------------*/
2218 /* Dump tree-specific information of block BB to file OUTF. */
2221 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2223 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
|TDF_MEMSYMS
);
2227 /* Dump a basic block on stderr. */
2230 debug_tree_bb (basic_block bb
)
2232 dump_bb (bb
, stderr
, 0);
2236 /* Dump basic block with index N on stderr. */
2239 debug_tree_bb_n (int n
)
2241 debug_tree_bb (BASIC_BLOCK (n
));
2242 return BASIC_BLOCK (n
);
2246 /* Dump the CFG on stderr.
2248 FLAGS are the same used by the tree dumping functions
2249 (see TDF_* in tree-pass.h). */
2252 debug_tree_cfg (int flags
)
2254 dump_tree_cfg (stderr
, flags
);
2258 /* Dump the program showing basic block boundaries on the given FILE.
2260 FLAGS are the same used by the tree dumping functions (see TDF_* in
2264 dump_tree_cfg (FILE *file
, int flags
)
2266 if (flags
& TDF_DETAILS
)
2268 const char *funcname
2269 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2272 fprintf (file
, ";; Function %s\n\n", funcname
);
2273 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2274 n_basic_blocks
, n_edges
, last_basic_block
);
2276 brief_dump_cfg (file
);
2277 fprintf (file
, "\n");
2280 if (flags
& TDF_STATS
)
2281 dump_cfg_stats (file
);
2283 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2287 /* Dump CFG statistics on FILE. */
2290 dump_cfg_stats (FILE *file
)
2292 static long max_num_merged_labels
= 0;
2293 unsigned long size
, total
= 0;
2296 const char * const fmt_str
= "%-30s%-13s%12s\n";
2297 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2298 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2299 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2300 const char *funcname
2301 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2304 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2306 fprintf (file
, "---------------------------------------------------------\n");
2307 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2308 fprintf (file
, fmt_str
, "", " instances ", "used ");
2309 fprintf (file
, "---------------------------------------------------------\n");
2311 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2313 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2314 SCALE (size
), LABEL (size
));
2318 num_edges
+= EDGE_COUNT (bb
->succs
);
2319 size
= num_edges
* sizeof (struct edge_def
);
2321 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2323 fprintf (file
, "---------------------------------------------------------\n");
2324 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2326 fprintf (file
, "---------------------------------------------------------\n");
2327 fprintf (file
, "\n");
2329 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2330 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2332 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2333 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2335 fprintf (file
, "\n");
2339 /* Dump CFG statistics on stderr. Keep extern so that it's always
2340 linked in the final executable. */
2343 debug_cfg_stats (void)
2345 dump_cfg_stats (stderr
);
2349 /* Dump the flowgraph to a .vcg FILE. */
2352 tree_cfg2vcg (FILE *file
)
2357 const char *funcname
2358 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2360 /* Write the file header. */
2361 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2362 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2363 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2365 /* Write blocks and edges. */
2366 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2368 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2371 if (e
->flags
& EDGE_FAKE
)
2372 fprintf (file
, " linestyle: dotted priority: 10");
2374 fprintf (file
, " linestyle: solid priority: 100");
2376 fprintf (file
, " }\n");
2382 enum tree_code head_code
, end_code
;
2383 const char *head_name
, *end_name
;
2386 tree first
= first_stmt (bb
);
2387 tree last
= last_stmt (bb
);
2391 head_code
= TREE_CODE (first
);
2392 head_name
= tree_code_name
[head_code
];
2393 head_line
= get_lineno (first
);
2396 head_name
= "no-statement";
2400 end_code
= TREE_CODE (last
);
2401 end_name
= tree_code_name
[end_code
];
2402 end_line
= get_lineno (last
);
2405 end_name
= "no-statement";
2407 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2408 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2411 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2413 if (e
->dest
== EXIT_BLOCK_PTR
)
2414 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2416 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2418 if (e
->flags
& EDGE_FAKE
)
2419 fprintf (file
, " priority: 10 linestyle: dotted");
2421 fprintf (file
, " priority: 100 linestyle: solid");
2423 fprintf (file
, " }\n");
2426 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2430 fputs ("}\n\n", file
);
2435 /*---------------------------------------------------------------------------
2436 Miscellaneous helpers
2437 ---------------------------------------------------------------------------*/
2439 /* Return true if T represents a stmt that always transfers control. */
2442 is_ctrl_stmt (tree t
)
2444 return (TREE_CODE (t
) == COND_EXPR
2445 || TREE_CODE (t
) == SWITCH_EXPR
2446 || TREE_CODE (t
) == GOTO_EXPR
2447 || TREE_CODE (t
) == RETURN_EXPR
2448 || TREE_CODE (t
) == RESX_EXPR
);
2452 /* Return true if T is a statement that may alter the flow of control
2453 (e.g., a call to a non-returning function). */
2456 is_ctrl_altering_stmt (tree t
)
2461 call
= get_call_expr_in (t
);
2464 /* A non-pure/const CALL_EXPR alters flow control if the current
2465 function has nonlocal labels. */
2466 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2469 /* A CALL_EXPR also alters control flow if it does not return. */
2470 if (call_expr_flags (call
) & ECF_NORETURN
)
2474 /* OpenMP directives alter control flow. */
2475 if (OMP_DIRECTIVE_P (t
))
2478 /* If a statement can throw, it alters control flow. */
2479 return tree_can_throw_internal (t
);
2483 /* Return true if T is a computed goto. */
2486 computed_goto_p (tree t
)
2488 return (TREE_CODE (t
) == GOTO_EXPR
2489 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2493 /* Return true if T is a simple local goto. */
2496 simple_goto_p (tree t
)
2498 return (TREE_CODE (t
) == GOTO_EXPR
2499 && TREE_CODE (GOTO_DESTINATION (t
)) == LABEL_DECL
);
2503 /* Return true if T can make an abnormal transfer of control flow.
2504 Transfers of control flow associated with EH are excluded. */
2507 tree_can_make_abnormal_goto (tree t
)
2509 if (computed_goto_p (t
))
2511 if (TREE_CODE (t
) == GIMPLE_MODIFY_STMT
)
2512 t
= GIMPLE_STMT_OPERAND (t
, 1);
2513 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2514 t
= TREE_OPERAND (t
, 0);
2515 if (TREE_CODE (t
) == CALL_EXPR
)
2516 return TREE_SIDE_EFFECTS (t
) && current_function_has_nonlocal_label
;
2521 /* Return true if T should start a new basic block. PREV_T is the
2522 statement preceding T. It is used when T is a label or a case label.
2523 Labels should only start a new basic block if their previous statement
2524 wasn't a label. Otherwise, sequence of labels would generate
2525 unnecessary basic blocks that only contain a single label. */
2528 stmt_starts_bb_p (tree t
, tree prev_t
)
2533 /* LABEL_EXPRs start a new basic block only if the preceding
2534 statement wasn't a label of the same type. This prevents the
2535 creation of consecutive blocks that have nothing but a single
2537 if (TREE_CODE (t
) == LABEL_EXPR
)
2539 /* Nonlocal and computed GOTO targets always start a new block. */
2540 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2541 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2544 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2546 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2549 cfg_stats
.num_merged_labels
++;
2560 /* Return true if T should end a basic block. */
2563 stmt_ends_bb_p (tree t
)
2565 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2569 /* Add gotos that used to be represented implicitly in the CFG. */
2572 disband_implicit_edges (void)
2575 block_stmt_iterator last
;
2582 last
= bsi_last (bb
);
2583 stmt
= last_stmt (bb
);
2585 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2587 /* Remove superfluous gotos from COND_EXPR branches. Moved
2588 from cfg_remove_useless_stmts here since it violates the
2589 invariants for tree--cfg correspondence and thus fits better
2590 here where we do it anyway. */
2591 e
= find_edge (bb
, bb
->next_bb
);
2594 if (e
->flags
& EDGE_TRUE_VALUE
)
2595 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2596 else if (e
->flags
& EDGE_FALSE_VALUE
)
2597 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2600 e
->flags
|= EDGE_FALLTHRU
;
2606 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2608 /* Remove the RETURN_EXPR if we may fall though to the exit
2610 gcc_assert (single_succ_p (bb
));
2611 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2613 if (bb
->next_bb
== EXIT_BLOCK_PTR
2614 && !TREE_OPERAND (stmt
, 0))
2616 bsi_remove (&last
, true);
2617 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2622 /* There can be no fallthru edge if the last statement is a control
2624 if (stmt
&& is_ctrl_stmt (stmt
))
2627 /* Find a fallthru edge and emit the goto if necessary. */
2628 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2629 if (e
->flags
& EDGE_FALLTHRU
)
2632 if (!e
|| e
->dest
== bb
->next_bb
)
2635 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2636 label
= tree_block_label (e
->dest
);
2638 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2639 #ifdef USE_MAPPED_LOCATION
2640 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2642 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2644 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2645 e
->flags
&= ~EDGE_FALLTHRU
;
2649 /* Remove block annotations and other datastructures. */
2652 delete_tree_cfg_annotations (void)
2654 label_to_block_map
= NULL
;
2658 /* Return the first statement in basic block BB. */
2661 first_stmt (basic_block bb
)
2663 block_stmt_iterator i
= bsi_start (bb
);
2664 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2668 /* Return the last statement in basic block BB. */
2671 last_stmt (basic_block bb
)
2673 block_stmt_iterator b
= bsi_last (bb
);
2674 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2678 /* Return the last statement of an otherwise empty block. Return NULL
2679 if the block is totally empty, or if it contains more than one
2683 last_and_only_stmt (basic_block bb
)
2685 block_stmt_iterator i
= bsi_last (bb
);
2691 last
= bsi_stmt (i
);
2696 /* Empty statements should no longer appear in the instruction stream.
2697 Everything that might have appeared before should be deleted by
2698 remove_useless_stmts, and the optimizers should just bsi_remove
2699 instead of smashing with build_empty_stmt.
2701 Thus the only thing that should appear here in a block containing
2702 one executable statement is a label. */
2703 prev
= bsi_stmt (i
);
2704 if (TREE_CODE (prev
) == LABEL_EXPR
)
2711 /* Mark BB as the basic block holding statement T. */
2714 set_bb_for_stmt (tree t
, basic_block bb
)
2716 if (TREE_CODE (t
) == PHI_NODE
)
2718 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2720 tree_stmt_iterator i
;
2721 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2722 set_bb_for_stmt (tsi_stmt (i
), bb
);
2726 stmt_ann_t ann
= get_stmt_ann (t
);
2729 /* If the statement is a label, add the label to block-to-labels map
2730 so that we can speed up edge creation for GOTO_EXPRs. */
2731 if (TREE_CODE (t
) == LABEL_EXPR
)
2735 t
= LABEL_EXPR_LABEL (t
);
2736 uid
= LABEL_DECL_UID (t
);
2739 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2740 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2741 if (old_len
<= (unsigned) uid
)
2743 unsigned new_len
= 3 * uid
/ 2;
2745 VEC_safe_grow_cleared (basic_block
, gc
, label_to_block_map
,
2750 /* We're moving an existing label. Make sure that we've
2751 removed it from the old block. */
2753 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2754 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2759 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2760 from one basic block to another.
2761 For BB splitting we can run into quadratic case, so performance is quite
2762 important and knowing that the tables are big enough, change_bb_for_stmt
2763 can inline as leaf function. */
2765 change_bb_for_stmt (tree t
, basic_block bb
)
2767 get_stmt_ann (t
)->bb
= bb
;
2768 if (TREE_CODE (t
) == LABEL_EXPR
)
2769 VEC_replace (basic_block
, label_to_block_map
,
2770 LABEL_DECL_UID (LABEL_EXPR_LABEL (t
)), bb
);
2773 /* Finds iterator for STMT. */
2775 extern block_stmt_iterator
2776 bsi_for_stmt (tree stmt
)
2778 block_stmt_iterator bsi
;
2780 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2781 if (bsi_stmt (bsi
) == stmt
)
2787 /* Mark statement T as modified, and update it. */
2789 update_modified_stmts (tree t
)
2791 if (!ssa_operands_active ())
2793 if (TREE_CODE (t
) == STATEMENT_LIST
)
2795 tree_stmt_iterator i
;
2797 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2799 stmt
= tsi_stmt (i
);
2800 update_stmt_if_modified (stmt
);
2804 update_stmt_if_modified (t
);
2807 /* Insert statement (or statement list) T before the statement
2808 pointed-to by iterator I. M specifies how to update iterator I
2809 after insertion (see enum bsi_iterator_update). */
2812 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2814 set_bb_for_stmt (t
, i
->bb
);
2815 update_modified_stmts (t
);
2816 tsi_link_before (&i
->tsi
, t
, m
);
2820 /* Insert statement (or statement list) T after the statement
2821 pointed-to by iterator I. M specifies how to update iterator I
2822 after insertion (see enum bsi_iterator_update). */
2825 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2827 set_bb_for_stmt (t
, i
->bb
);
2828 update_modified_stmts (t
);
2829 tsi_link_after (&i
->tsi
, t
, m
);
2833 /* Remove the statement pointed to by iterator I. The iterator is updated
2834 to the next statement.
2836 When REMOVE_EH_INFO is true we remove the statement pointed to by
2837 iterator I from the EH tables. Otherwise we do not modify the EH
2840 Generally, REMOVE_EH_INFO should be true when the statement is going to
2841 be removed from the IL and not reinserted elsewhere. */
2844 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2846 tree t
= bsi_stmt (*i
);
2847 set_bb_for_stmt (t
, NULL
);
2848 delink_stmt_imm_use (t
);
2849 tsi_delink (&i
->tsi
);
2850 mark_stmt_modified (t
);
2853 remove_stmt_from_eh_region (t
);
2854 gimple_remove_stmt_histograms (cfun
, t
);
2859 /* Move the statement at FROM so it comes right after the statement at TO. */
2862 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2864 tree stmt
= bsi_stmt (*from
);
2865 bsi_remove (from
, false);
2866 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2870 /* Move the statement at FROM so it comes right before the statement at TO. */
2873 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2875 tree stmt
= bsi_stmt (*from
);
2876 bsi_remove (from
, false);
2877 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2881 /* Move the statement at FROM to the end of basic block BB. */
2884 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2886 block_stmt_iterator last
= bsi_last (bb
);
2888 /* Have to check bsi_end_p because it could be an empty block. */
2889 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2890 bsi_move_before (from
, &last
);
2892 bsi_move_after (from
, &last
);
2896 /* Replace the contents of the statement pointed to by iterator BSI
2897 with STMT. If UPDATE_EH_INFO is true, the exception handling
2898 information of the original statement is moved to the new statement. */
2901 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2904 tree orig_stmt
= bsi_stmt (*bsi
);
2906 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2907 set_bb_for_stmt (stmt
, bsi
->bb
);
2909 /* Preserve EH region information from the original statement, if
2910 requested by the caller. */
2913 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2916 remove_stmt_from_eh_region (orig_stmt
);
2917 add_stmt_to_eh_region (stmt
, eh_region
);
2918 gimple_duplicate_stmt_histograms (cfun
, stmt
, cfun
, orig_stmt
);
2919 gimple_remove_stmt_histograms (cfun
, orig_stmt
);
2923 delink_stmt_imm_use (orig_stmt
);
2924 *bsi_stmt_ptr (*bsi
) = stmt
;
2925 mark_stmt_modified (stmt
);
2926 update_modified_stmts (stmt
);
2930 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2931 is made to place the statement in an existing basic block, but
2932 sometimes that isn't possible. When it isn't possible, the edge is
2933 split and the statement is added to the new block.
2935 In all cases, the returned *BSI points to the correct location. The
2936 return value is true if insertion should be done after the location,
2937 or false if it should be done before the location. If new basic block
2938 has to be created, it is stored in *NEW_BB. */
2941 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2942 basic_block
*new_bb
)
2944 basic_block dest
, src
;
2950 /* If the destination has one predecessor which has no PHI nodes,
2951 insert there. Except for the exit block.
2953 The requirement for no PHI nodes could be relaxed. Basically we
2954 would have to examine the PHIs to prove that none of them used
2955 the value set by the statement we want to insert on E. That
2956 hardly seems worth the effort. */
2957 if (single_pred_p (dest
)
2958 && ! phi_nodes (dest
)
2959 && dest
!= EXIT_BLOCK_PTR
)
2961 *bsi
= bsi_start (dest
);
2962 if (bsi_end_p (*bsi
))
2965 /* Make sure we insert after any leading labels. */
2966 tmp
= bsi_stmt (*bsi
);
2967 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2970 if (bsi_end_p (*bsi
))
2972 tmp
= bsi_stmt (*bsi
);
2975 if (bsi_end_p (*bsi
))
2977 *bsi
= bsi_last (dest
);
2984 /* If the source has one successor, the edge is not abnormal and
2985 the last statement does not end a basic block, insert there.
2986 Except for the entry block. */
2988 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2989 && single_succ_p (src
)
2990 && src
!= ENTRY_BLOCK_PTR
)
2992 *bsi
= bsi_last (src
);
2993 if (bsi_end_p (*bsi
))
2996 tmp
= bsi_stmt (*bsi
);
2997 if (!stmt_ends_bb_p (tmp
))
3000 /* Insert code just before returning the value. We may need to decompose
3001 the return in the case it contains non-trivial operand. */
3002 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3004 tree op
= TREE_OPERAND (tmp
, 0);
3005 if (op
&& !is_gimple_val (op
))
3007 gcc_assert (TREE_CODE (op
) == GIMPLE_MODIFY_STMT
);
3008 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3009 TREE_OPERAND (tmp
, 0) = GIMPLE_STMT_OPERAND (op
, 0);
3016 /* Otherwise, create a new basic block, and split this edge. */
3017 dest
= split_edge (e
);
3020 e
= single_pred_edge (dest
);
3025 /* This routine will commit all pending edge insertions, creating any new
3026 basic blocks which are necessary. */
3029 bsi_commit_edge_inserts (void)
3035 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3038 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3039 bsi_commit_one_edge_insert (e
, NULL
);
3043 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3044 to this block, otherwise set it to NULL. */
3047 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3051 if (PENDING_STMT (e
))
3053 block_stmt_iterator bsi
;
3054 tree stmt
= PENDING_STMT (e
);
3056 PENDING_STMT (e
) = NULL_TREE
;
3058 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3059 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3061 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3066 /* Add STMT to the pending list of edge E. No actual insertion is
3067 made until a call to bsi_commit_edge_inserts () is made. */
3070 bsi_insert_on_edge (edge e
, tree stmt
)
3072 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3075 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3076 block has to be created, it is returned. */
3079 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3081 block_stmt_iterator bsi
;
3082 basic_block new_bb
= NULL
;
3084 gcc_assert (!PENDING_STMT (e
));
3086 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3087 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3089 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3094 /*---------------------------------------------------------------------------
3095 Tree specific functions for CFG manipulation
3096 ---------------------------------------------------------------------------*/
3098 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3101 reinstall_phi_args (edge new_edge
, edge old_edge
)
3105 if (!PENDING_STMT (old_edge
))
3108 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3110 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3112 tree result
= TREE_PURPOSE (var
);
3113 tree arg
= TREE_VALUE (var
);
3115 gcc_assert (result
== PHI_RESULT (phi
));
3117 add_phi_arg (phi
, arg
, new_edge
);
3120 PENDING_STMT (old_edge
) = NULL
;
3123 /* Returns the basic block after which the new basic block created
3124 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3125 near its "logical" location. This is of most help to humans looking
3126 at debugging dumps. */
3129 split_edge_bb_loc (edge edge_in
)
3131 basic_block dest
= edge_in
->dest
;
3133 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3134 return edge_in
->src
;
3136 return dest
->prev_bb
;
3139 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3140 Abort on abnormal edges. */
3143 tree_split_edge (edge edge_in
)
3145 basic_block new_bb
, after_bb
, dest
;
3148 /* Abnormal edges cannot be split. */
3149 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3151 dest
= edge_in
->dest
;
3153 after_bb
= split_edge_bb_loc (edge_in
);
3155 new_bb
= create_empty_bb (after_bb
);
3156 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3157 new_bb
->count
= edge_in
->count
;
3158 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3159 new_edge
->probability
= REG_BR_PROB_BASE
;
3160 new_edge
->count
= edge_in
->count
;
3162 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3164 reinstall_phi_args (new_edge
, e
);
3170 /* Return true when BB has label LABEL in it. */
3173 has_label_p (basic_block bb
, tree label
)
3175 block_stmt_iterator bsi
;
3177 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3179 tree stmt
= bsi_stmt (bsi
);
3181 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3183 if (LABEL_EXPR_LABEL (stmt
) == label
)
3190 /* Callback for walk_tree, check that all elements with address taken are
3191 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3192 inside a PHI node. */
3195 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3198 bool in_phi
= (data
!= NULL
);
3203 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3204 #define CHECK_OP(N, MSG) \
3205 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3206 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3208 switch (TREE_CODE (t
))
3211 if (SSA_NAME_IN_FREE_LIST (t
))
3213 error ("SSA name in freelist but still referenced");
3219 x
= fold (ASSERT_EXPR_COND (t
));
3220 if (x
== boolean_false_node
)
3222 error ("ASSERT_EXPR with an always-false condition");
3230 case GIMPLE_MODIFY_STMT
:
3231 x
= GIMPLE_STMT_OPERAND (t
, 0);
3232 if (TREE_CODE (x
) == BIT_FIELD_REF
3233 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3235 error ("GIMPLE register modified with BIT_FIELD_REF");
3244 bool old_side_effects
;
3247 bool new_side_effects
;
3249 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3250 dead PHIs that take the address of something. But if the PHI
3251 result is dead, the fact that it takes the address of anything
3252 is irrelevant. Because we can not tell from here if a PHI result
3253 is dead, we just skip this check for PHIs altogether. This means
3254 we may be missing "valid" checks, but what can you do?
3255 This was PR19217. */
3259 old_invariant
= TREE_INVARIANT (t
);
3260 old_constant
= TREE_CONSTANT (t
);
3261 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3263 recompute_tree_invariant_for_addr_expr (t
);
3264 new_invariant
= TREE_INVARIANT (t
);
3265 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3266 new_constant
= TREE_CONSTANT (t
);
3268 if (old_invariant
!= new_invariant
)
3270 error ("invariant not recomputed when ADDR_EXPR changed");
3274 if (old_constant
!= new_constant
)
3276 error ("constant not recomputed when ADDR_EXPR changed");
3279 if (old_side_effects
!= new_side_effects
)
3281 error ("side effects not recomputed when ADDR_EXPR changed");
3285 /* Skip any references (they will be checked when we recurse down the
3286 tree) and ensure that any variable used as a prefix is marked
3288 for (x
= TREE_OPERAND (t
, 0);
3289 handled_component_p (x
);
3290 x
= TREE_OPERAND (x
, 0))
3293 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3295 if (!TREE_ADDRESSABLE (x
))
3297 error ("address taken, but ADDRESSABLE bit not set");
3304 x
= COND_EXPR_COND (t
);
3305 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3307 error ("non-boolean used in condition");
3310 if (!is_gimple_condexpr (x
))
3312 error ("invalid conditional operand");
3319 case FIX_TRUNC_EXPR
:
3324 case NON_LVALUE_EXPR
:
3325 case TRUTH_NOT_EXPR
:
3326 CHECK_OP (0, "invalid operand to unary operator");
3333 case ARRAY_RANGE_REF
:
3335 case VIEW_CONVERT_EXPR
:
3336 /* We have a nest of references. Verify that each of the operands
3337 that determine where to reference is either a constant or a variable,
3338 verify that the base is valid, and then show we've already checked
3340 while (handled_component_p (t
))
3342 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3343 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3344 else if (TREE_CODE (t
) == ARRAY_REF
3345 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3347 CHECK_OP (1, "invalid array index");
3348 if (TREE_OPERAND (t
, 2))
3349 CHECK_OP (2, "invalid array lower bound");
3350 if (TREE_OPERAND (t
, 3))
3351 CHECK_OP (3, "invalid array stride");
3353 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3355 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3356 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3359 t
= TREE_OPERAND (t
, 0);
3362 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3364 error ("invalid reference prefix");
3376 case UNORDERED_EXPR
:
3387 case TRUNC_DIV_EXPR
:
3389 case FLOOR_DIV_EXPR
:
3390 case ROUND_DIV_EXPR
:
3391 case TRUNC_MOD_EXPR
:
3393 case FLOOR_MOD_EXPR
:
3394 case ROUND_MOD_EXPR
:
3396 case EXACT_DIV_EXPR
:
3406 CHECK_OP (0, "invalid operand to binary operator");
3407 CHECK_OP (1, "invalid operand to binary operator");
3411 if (TREE_CONSTANT (t
) && TREE_CODE (TREE_TYPE (t
)) == VECTOR_TYPE
)
3424 /* Verify STMT, return true if STMT is not in GIMPLE form.
3425 TODO: Implement type checking. */
3428 verify_stmt (tree stmt
, bool last_in_block
)
3432 if (OMP_DIRECTIVE_P (stmt
))
3434 /* OpenMP directives are validated by the FE and never operated
3435 on by the optimizers. Furthermore, OMP_FOR may contain
3436 non-gimple expressions when the main index variable has had
3437 its address taken. This does not affect the loop itself
3438 because the header of an OMP_FOR is merely used to determine
3439 how to setup the parallel iteration. */
3443 if (!is_gimple_stmt (stmt
))
3445 error ("is not a valid GIMPLE statement");
3449 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3452 debug_generic_stmt (addr
);
3456 /* If the statement is marked as part of an EH region, then it is
3457 expected that the statement could throw. Verify that when we
3458 have optimizations that simplify statements such that we prove
3459 that they cannot throw, that we update other data structures
3461 if (lookup_stmt_eh_region (stmt
) >= 0)
3463 if (!tree_could_throw_p (stmt
))
3465 error ("statement marked for throw, but doesn%'t");
3468 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3470 error ("statement marked for throw in middle of block");
3478 debug_generic_stmt (stmt
);
3483 /* Return true when the T can be shared. */
3486 tree_node_can_be_shared (tree t
)
3488 if (IS_TYPE_OR_DECL_P (t
)
3489 || is_gimple_min_invariant (t
)
3490 || TREE_CODE (t
) == SSA_NAME
3491 || t
== error_mark_node
3492 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3495 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3498 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3499 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3500 || TREE_CODE (t
) == COMPONENT_REF
3501 || TREE_CODE (t
) == REALPART_EXPR
3502 || TREE_CODE (t
) == IMAGPART_EXPR
)
3503 t
= TREE_OPERAND (t
, 0);
3512 /* Called via walk_trees. Verify tree sharing. */
3515 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3517 htab_t htab
= (htab_t
) data
;
3520 if (tree_node_can_be_shared (*tp
))
3522 *walk_subtrees
= false;
3526 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3528 return (tree
) *slot
;
3535 /* Helper function for verify_gimple_tuples. */
3538 verify_gimple_tuples_1 (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
3539 void *data ATTRIBUTE_UNUSED
)
3541 switch (TREE_CODE (*tp
))
3544 error ("unexpected non-tuple");
3554 /* Verify that there are no trees that should have been converted to
3555 gimple tuples. Return true if T contains a node that should have
3556 been converted to a gimple tuple, but hasn't. */
3559 verify_gimple_tuples (tree t
)
3561 return walk_tree (&t
, verify_gimple_tuples_1
, NULL
, NULL
) != NULL
;
3564 /* Verify the GIMPLE statement chain. */
3570 block_stmt_iterator bsi
;
3575 timevar_push (TV_TREE_STMT_VERIFY
);
3576 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3583 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3585 int phi_num_args
= PHI_NUM_ARGS (phi
);
3587 if (bb_for_stmt (phi
) != bb
)
3589 error ("bb_for_stmt (phi) is set to a wrong basic block");
3593 for (i
= 0; i
< phi_num_args
; i
++)
3595 tree t
= PHI_ARG_DEF (phi
, i
);
3598 /* Addressable variables do have SSA_NAMEs but they
3599 are not considered gimple values. */
3600 if (TREE_CODE (t
) != SSA_NAME
3601 && TREE_CODE (t
) != FUNCTION_DECL
3602 && !is_gimple_val (t
))
3604 error ("PHI def is not a GIMPLE value");
3605 debug_generic_stmt (phi
);
3606 debug_generic_stmt (t
);
3610 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3613 debug_generic_stmt (addr
);
3617 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3620 error ("incorrect sharing of tree nodes");
3621 debug_generic_stmt (phi
);
3622 debug_generic_stmt (addr
);
3628 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3630 tree stmt
= bsi_stmt (bsi
);
3632 err
|= verify_gimple_tuples (stmt
);
3634 if (bb_for_stmt (stmt
) != bb
)
3636 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3641 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3642 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3645 error ("incorrect sharing of tree nodes");
3646 debug_generic_stmt (stmt
);
3647 debug_generic_stmt (addr
);
3654 internal_error ("verify_stmts failed");
3657 verify_histograms ();
3658 timevar_pop (TV_TREE_STMT_VERIFY
);
3662 /* Verifies that the flow information is OK. */
3665 tree_verify_flow_info (void)
3669 block_stmt_iterator bsi
;
3674 if (ENTRY_BLOCK_PTR
->stmt_list
)
3676 error ("ENTRY_BLOCK has a statement list associated with it");
3680 if (EXIT_BLOCK_PTR
->stmt_list
)
3682 error ("EXIT_BLOCK has a statement list associated with it");
3686 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3687 if (e
->flags
& EDGE_FALLTHRU
)
3689 error ("fallthru to exit from bb %d", e
->src
->index
);
3695 bool found_ctrl_stmt
= false;
3699 /* Skip labels on the start of basic block. */
3700 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3702 tree prev_stmt
= stmt
;
3704 stmt
= bsi_stmt (bsi
);
3706 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3709 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3711 error ("nonlocal label ");
3712 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3713 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3718 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3721 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3722 fprintf (stderr
, " to block does not match in bb %d",
3727 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3728 != current_function_decl
)
3731 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3732 fprintf (stderr
, " has incorrect context in bb %d",
3738 /* Verify that body of basic block BB is free of control flow. */
3739 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3741 tree stmt
= bsi_stmt (bsi
);
3743 if (found_ctrl_stmt
)
3745 error ("control flow in the middle of basic block %d",
3750 if (stmt_ends_bb_p (stmt
))
3751 found_ctrl_stmt
= true;
3753 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3756 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3757 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3762 bsi
= bsi_last (bb
);
3763 if (bsi_end_p (bsi
))
3766 stmt
= bsi_stmt (bsi
);
3768 err
|= verify_eh_edges (stmt
);
3770 if (is_ctrl_stmt (stmt
))
3772 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3773 if (e
->flags
& EDGE_FALLTHRU
)
3775 error ("fallthru edge after a control statement in bb %d",
3781 if (TREE_CODE (stmt
) != COND_EXPR
)
3783 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3784 after anything else but if statement. */
3785 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3786 if (e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
))
3788 error ("true/false edge after a non-COND_EXPR in bb %d",
3794 switch (TREE_CODE (stmt
))
3800 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3801 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3803 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3807 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3809 if (!true_edge
|| !false_edge
3810 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3811 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3812 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3813 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3814 || EDGE_COUNT (bb
->succs
) >= 3)
3816 error ("wrong outgoing edge flags at end of bb %d",
3821 if (!has_label_p (true_edge
->dest
,
3822 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3824 error ("%<then%> label does not match edge at end of bb %d",
3829 if (!has_label_p (false_edge
->dest
,
3830 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3832 error ("%<else%> label does not match edge at end of bb %d",
3840 if (simple_goto_p (stmt
))
3842 error ("explicit goto at end of bb %d", bb
->index
);
3847 /* FIXME. We should double check that the labels in the
3848 destination blocks have their address taken. */
3849 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3850 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3851 | EDGE_FALSE_VALUE
))
3852 || !(e
->flags
& EDGE_ABNORMAL
))
3854 error ("wrong outgoing edge flags at end of bb %d",
3862 if (!single_succ_p (bb
)
3863 || (single_succ_edge (bb
)->flags
3864 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3865 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3867 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3870 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3872 error ("return edge does not point to exit in bb %d",
3885 vec
= SWITCH_LABELS (stmt
);
3886 n
= TREE_VEC_LENGTH (vec
);
3888 /* Mark all the destination basic blocks. */
3889 for (i
= 0; i
< n
; ++i
)
3891 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3892 basic_block label_bb
= label_to_block (lab
);
3894 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3895 label_bb
->aux
= (void *)1;
3898 /* Verify that the case labels are sorted. */
3899 prev
= TREE_VEC_ELT (vec
, 0);
3900 for (i
= 1; i
< n
- 1; ++i
)
3902 tree c
= TREE_VEC_ELT (vec
, i
);
3905 error ("found default case not at end of case vector");
3909 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3911 error ("case labels not sorted: ");
3912 print_generic_expr (stderr
, prev
, 0);
3913 fprintf (stderr
," is greater than ");
3914 print_generic_expr (stderr
, c
, 0);
3915 fprintf (stderr
," but comes before it.\n");
3920 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3922 error ("no default case found at end of case vector");
3926 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3930 error ("extra outgoing edge %d->%d",
3931 bb
->index
, e
->dest
->index
);
3934 e
->dest
->aux
= (void *)2;
3935 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3936 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3938 error ("wrong outgoing edge flags at end of bb %d",
3944 /* Check that we have all of them. */
3945 for (i
= 0; i
< n
; ++i
)
3947 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3948 basic_block label_bb
= label_to_block (lab
);
3950 if (label_bb
->aux
!= (void *)2)
3952 error ("missing edge %i->%i",
3953 bb
->index
, label_bb
->index
);
3958 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3959 e
->dest
->aux
= (void *)0;
3966 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3967 verify_dominators (CDI_DOMINATORS
);
3973 /* Updates phi nodes after creating a forwarder block joined
3974 by edge FALLTHRU. */
3977 tree_make_forwarder_block (edge fallthru
)
3981 basic_block dummy
, bb
;
3982 tree phi
, new_phi
, var
;
3984 dummy
= fallthru
->src
;
3985 bb
= fallthru
->dest
;
3987 if (single_pred_p (bb
))
3990 /* If we redirected a branch we must create new PHI nodes at the
3992 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3994 var
= PHI_RESULT (phi
);
3995 new_phi
= create_phi_node (var
, bb
);
3996 SSA_NAME_DEF_STMT (var
) = new_phi
;
3997 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3998 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
4001 /* Ensure that the PHI node chain is in the same order. */
4002 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
4004 /* Add the arguments we have stored on edges. */
4005 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4010 flush_pending_stmts (e
);
4015 /* Return a non-special label in the head of basic block BLOCK.
4016 Create one if it doesn't exist. */
4019 tree_block_label (basic_block bb
)
4021 block_stmt_iterator i
, s
= bsi_start (bb
);
4025 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4027 stmt
= bsi_stmt (i
);
4028 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4030 label
= LABEL_EXPR_LABEL (stmt
);
4031 if (!DECL_NONLOCAL (label
))
4034 bsi_move_before (&i
, &s
);
4039 label
= create_artificial_label ();
4040 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4041 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4046 /* Attempt to perform edge redirection by replacing a possibly complex
4047 jump instruction by a goto or by removing the jump completely.
4048 This can apply only if all edges now point to the same block. The
4049 parameters and return values are equivalent to
4050 redirect_edge_and_branch. */
4053 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4055 basic_block src
= e
->src
;
4056 block_stmt_iterator b
;
4059 /* We can replace or remove a complex jump only when we have exactly
4061 if (EDGE_COUNT (src
->succs
) != 2
4062 /* Verify that all targets will be TARGET. Specifically, the
4063 edge that is not E must also go to TARGET. */
4064 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4070 stmt
= bsi_stmt (b
);
4072 if (TREE_CODE (stmt
) == COND_EXPR
4073 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4075 bsi_remove (&b
, true);
4076 e
= ssa_redirect_edge (e
, target
);
4077 e
->flags
= EDGE_FALLTHRU
;
4085 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4086 edge representing the redirected branch. */
4089 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4091 basic_block bb
= e
->src
;
4092 block_stmt_iterator bsi
;
4096 if (e
->flags
& EDGE_ABNORMAL
)
4099 if (e
->src
!= ENTRY_BLOCK_PTR
4100 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4103 if (e
->dest
== dest
)
4106 label
= tree_block_label (dest
);
4108 bsi
= bsi_last (bb
);
4109 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4111 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4114 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4115 ? COND_EXPR_THEN (stmt
)
4116 : COND_EXPR_ELSE (stmt
));
4117 GOTO_DESTINATION (stmt
) = label
;
4121 /* No non-abnormal edges should lead from a non-simple goto, and
4122 simple ones should be represented implicitly. */
4127 tree cases
= get_cases_for_edge (e
, stmt
);
4129 /* If we have a list of cases associated with E, then use it
4130 as it's a lot faster than walking the entire case vector. */
4133 edge e2
= find_edge (e
->src
, dest
);
4140 CASE_LABEL (cases
) = label
;
4141 cases
= TREE_CHAIN (cases
);
4144 /* If there was already an edge in the CFG, then we need
4145 to move all the cases associated with E to E2. */
4148 tree cases2
= get_cases_for_edge (e2
, stmt
);
4150 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4151 TREE_CHAIN (cases2
) = first
;
4156 tree vec
= SWITCH_LABELS (stmt
);
4157 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4159 for (i
= 0; i
< n
; i
++)
4161 tree elt
= TREE_VEC_ELT (vec
, i
);
4163 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4164 CASE_LABEL (elt
) = label
;
4172 bsi_remove (&bsi
, true);
4173 e
->flags
|= EDGE_FALLTHRU
;
4177 /* Otherwise it must be a fallthru edge, and we don't need to
4178 do anything besides redirecting it. */
4179 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4183 /* Update/insert PHI nodes as necessary. */
4185 /* Now update the edges in the CFG. */
4186 e
= ssa_redirect_edge (e
, dest
);
4192 /* Simple wrapper, as we can always redirect fallthru edges. */
4195 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4197 e
= tree_redirect_edge_and_branch (e
, dest
);
4204 /* Splits basic block BB after statement STMT (but at least after the
4205 labels). If STMT is NULL, BB is split just after the labels. */
4208 tree_split_block (basic_block bb
, void *stmt
)
4210 block_stmt_iterator bsi
;
4211 tree_stmt_iterator tsi_tgt
;
4217 new_bb
= create_empty_bb (bb
);
4219 /* Redirect the outgoing edges. */
4220 new_bb
->succs
= bb
->succs
;
4222 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4225 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4228 /* Move everything from BSI to the new basic block. */
4229 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4231 act
= bsi_stmt (bsi
);
4232 if (TREE_CODE (act
) == LABEL_EXPR
)
4245 if (bsi_end_p (bsi
))
4248 /* Split the statement list - avoid re-creating new containers as this
4249 brings ugly quadratic memory consumption in the inliner.
4250 (We are still quadratic since we need to update stmt BB pointers,
4252 new_bb
->stmt_list
= tsi_split_statement_list_before (&bsi
.tsi
);
4253 for (tsi_tgt
= tsi_start (new_bb
->stmt_list
);
4254 !tsi_end_p (tsi_tgt
); tsi_next (&tsi_tgt
))
4255 change_bb_for_stmt (tsi_stmt (tsi_tgt
), new_bb
);
4261 /* Moves basic block BB after block AFTER. */
4264 tree_move_block_after (basic_block bb
, basic_block after
)
4266 if (bb
->prev_bb
== after
)
4270 link_block (bb
, after
);
4276 /* Return true if basic_block can be duplicated. */
4279 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4285 /* Create a duplicate of the basic block BB. NOTE: This does not
4286 preserve SSA form. */
4289 tree_duplicate_bb (basic_block bb
)
4292 block_stmt_iterator bsi
, bsi_tgt
;
4295 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4297 /* Copy the PHI nodes. We ignore PHI node arguments here because
4298 the incoming edges have not been setup yet. */
4299 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4301 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4302 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4305 /* Keep the chain of PHI nodes in the same order so that they can be
4306 updated by ssa_redirect_edge. */
4307 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4309 bsi_tgt
= bsi_start (new_bb
);
4310 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4312 def_operand_p def_p
;
4313 ssa_op_iter op_iter
;
4317 stmt
= bsi_stmt (bsi
);
4318 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4321 /* Create a new copy of STMT and duplicate STMT's virtual
4323 copy
= unshare_expr (stmt
);
4324 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4325 copy_virtual_operands (copy
, stmt
);
4326 region
= lookup_stmt_eh_region (stmt
);
4328 add_stmt_to_eh_region (copy
, region
);
4329 gimple_duplicate_stmt_histograms (cfun
, copy
, cfun
, stmt
);
4331 /* Create new names for all the definitions created by COPY and
4332 add replacement mappings for each new name. */
4333 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4334 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4341 /* Basic block BB_COPY was created by code duplication. Add phi node
4342 arguments for edges going out of BB_COPY. The blocks that were
4343 duplicated have BB_DUPLICATED set. */
4346 add_phi_args_after_copy_bb (basic_block bb_copy
)
4348 basic_block bb
, dest
;
4351 tree phi
, phi_copy
, phi_next
, def
;
4353 bb
= get_bb_original (bb_copy
);
4355 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4357 if (!phi_nodes (e_copy
->dest
))
4360 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4361 dest
= get_bb_original (e_copy
->dest
);
4363 dest
= e_copy
->dest
;
4365 e
= find_edge (bb
, dest
);
4368 /* During loop unrolling the target of the latch edge is copied.
4369 In this case we are not looking for edge to dest, but to
4370 duplicated block whose original was dest. */
4371 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4372 if ((e
->dest
->flags
& BB_DUPLICATED
)
4373 && get_bb_original (e
->dest
) == dest
)
4376 gcc_assert (e
!= NULL
);
4379 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4381 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4383 phi_next
= PHI_CHAIN (phi
);
4384 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4385 add_phi_arg (phi_copy
, def
, e_copy
);
4390 /* Blocks in REGION_COPY array of length N_REGION were created by
4391 duplication of basic blocks. Add phi node arguments for edges
4392 going from these blocks. */
4395 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4399 for (i
= 0; i
< n_region
; i
++)
4400 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4402 for (i
= 0; i
< n_region
; i
++)
4403 add_phi_args_after_copy_bb (region_copy
[i
]);
4405 for (i
= 0; i
< n_region
; i
++)
4406 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4409 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4410 important exit edge EXIT. By important we mean that no SSA name defined
4411 inside region is live over the other exit edges of the region. All entry
4412 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4413 to the duplicate of the region. SSA form, dominance and loop information
4414 is updated. The new basic blocks are stored to REGION_COPY in the same
4415 order as they had in REGION, provided that REGION_COPY is not NULL.
4416 The function returns false if it is unable to copy the region,
4420 tree_duplicate_sese_region (edge entry
, edge exit
,
4421 basic_block
*region
, unsigned n_region
,
4422 basic_block
*region_copy
)
4425 bool free_region_copy
= false, copying_header
= false;
4426 struct loop
*loop
= entry
->dest
->loop_father
;
4430 int total_freq
= 0, entry_freq
= 0;
4431 gcov_type total_count
= 0, entry_count
= 0;
4433 if (!can_copy_bbs_p (region
, n_region
))
4436 /* Some sanity checking. Note that we do not check for all possible
4437 missuses of the functions. I.e. if you ask to copy something weird,
4438 it will work, but the state of structures probably will not be
4440 for (i
= 0; i
< n_region
; i
++)
4442 /* We do not handle subloops, i.e. all the blocks must belong to the
4444 if (region
[i
]->loop_father
!= loop
)
4447 if (region
[i
] != entry
->dest
4448 && region
[i
] == loop
->header
)
4454 /* In case the function is used for loop header copying (which is the primary
4455 use), ensure that EXIT and its copy will be new latch and entry edges. */
4456 if (loop
->header
== entry
->dest
)
4458 copying_header
= true;
4459 loop
->copy
= loop
->outer
;
4461 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4464 for (i
= 0; i
< n_region
; i
++)
4465 if (region
[i
] != exit
->src
4466 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4472 region_copy
= XNEWVEC (basic_block
, n_region
);
4473 free_region_copy
= true;
4476 gcc_assert (!need_ssa_update_p ());
4478 /* Record blocks outside the region that are dominated by something
4480 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4481 initialize_original_copy_tables ();
4483 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4485 if (entry
->dest
->count
)
4487 total_count
= entry
->dest
->count
;
4488 entry_count
= entry
->count
;
4489 /* Fix up corner cases, to avoid division by zero or creation of negative
4491 if (entry_count
> total_count
)
4492 entry_count
= total_count
;
4496 total_freq
= entry
->dest
->frequency
;
4497 entry_freq
= EDGE_FREQUENCY (entry
);
4498 /* Fix up corner cases, to avoid division by zero or creation of negative
4500 if (total_freq
== 0)
4502 else if (entry_freq
> total_freq
)
4503 entry_freq
= total_freq
;
4506 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4507 split_edge_bb_loc (entry
));
4510 scale_bbs_frequencies_gcov_type (region
, n_region
,
4511 total_count
- entry_count
,
4513 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4518 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4520 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4525 loop
->header
= exit
->dest
;
4526 loop
->latch
= exit
->src
;
4529 /* Redirect the entry and add the phi node arguments. */
4530 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4531 gcc_assert (redirected
!= NULL
);
4532 flush_pending_stmts (entry
);
4534 /* Concerning updating of dominators: We must recount dominators
4535 for entry block and its copy. Anything that is outside of the
4536 region, but was dominated by something inside needs recounting as
4538 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4539 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4540 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4543 /* Add the other PHI node arguments. */
4544 add_phi_args_after_copy (region_copy
, n_region
);
4546 /* Update the SSA web. */
4547 update_ssa (TODO_update_ssa
);
4549 if (free_region_copy
)
4552 free_original_copy_tables ();
4557 DEF_VEC_P(basic_block);
4558 DEF_VEC_ALLOC_P(basic_block,heap);
4561 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4562 adding blocks when the dominator traversal reaches EXIT. This
4563 function silently assumes that ENTRY strictly dominates EXIT. */
4566 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4567 VEC(basic_block
,heap
) **bbs_p
)
4571 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4573 son
= next_dom_son (CDI_DOMINATORS
, son
))
4575 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4577 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4587 bitmap vars_to_remove
;
4588 htab_t new_label_map
;
4592 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4593 contained in *TP and change the DECL_CONTEXT of every local
4594 variable referenced in *TP. */
4597 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4599 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4603 && (EXPR_P (t
) || GIMPLE_STMT_P (t
)))
4604 TREE_BLOCK (t
) = p
->block
;
4606 if (OMP_DIRECTIVE_P (t
)
4607 && TREE_CODE (t
) != OMP_RETURN
4608 && TREE_CODE (t
) != OMP_CONTINUE
)
4610 /* Do not remap variables inside OMP directives. Variables
4611 referenced in clauses and directive header belong to the
4612 parent function and should not be moved into the child
4614 bool save_remap_decls_p
= p
->remap_decls_p
;
4615 p
->remap_decls_p
= false;
4618 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4620 p
->remap_decls_p
= save_remap_decls_p
;
4622 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4624 if (TREE_CODE (t
) == LABEL_DECL
)
4626 if (p
->new_label_map
)
4628 struct tree_map in
, *out
;
4630 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4635 DECL_CONTEXT (t
) = p
->to_context
;
4637 else if (p
->remap_decls_p
)
4639 DECL_CONTEXT (t
) = p
->to_context
;
4641 if (TREE_CODE (t
) == VAR_DECL
)
4643 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4644 f
->unexpanded_var_list
4645 = tree_cons (0, t
, f
->unexpanded_var_list
);
4647 /* Mark T to be removed from the original function,
4648 otherwise it will be given a DECL_RTL when the
4649 original function is expanded. */
4650 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4654 else if (TYPE_P (t
))
4661 /* Move basic block BB from function CFUN to function DEST_FN. The
4662 block is moved out of the original linked list and placed after
4663 block AFTER in the new list. Also, the block is removed from the
4664 original array of blocks and placed in DEST_FN's array of blocks.
4665 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4666 updated to reflect the moved edges.
4668 On exit, local variables that need to be removed from
4669 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4672 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4673 basic_block after
, bool update_edge_count_p
,
4674 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4676 struct control_flow_graph
*cfg
;
4679 block_stmt_iterator si
;
4680 struct move_stmt_d d
;
4681 unsigned old_len
, new_len
;
4683 /* Link BB to the new linked list. */
4684 move_block_after (bb
, after
);
4686 /* Update the edge count in the corresponding flowgraphs. */
4687 if (update_edge_count_p
)
4688 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4690 cfun
->cfg
->x_n_edges
--;
4691 dest_cfun
->cfg
->x_n_edges
++;
4694 /* Remove BB from the original basic block array. */
4695 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4696 cfun
->cfg
->x_n_basic_blocks
--;
4698 /* Grow DEST_CFUN's basic block array if needed. */
4699 cfg
= dest_cfun
->cfg
;
4700 cfg
->x_n_basic_blocks
++;
4701 if (bb
->index
> cfg
->x_last_basic_block
)
4702 cfg
->x_last_basic_block
= bb
->index
;
4704 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4705 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4707 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4708 VEC_safe_grow_cleared (basic_block
, gc
, cfg
->x_basic_block_info
,
4712 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4713 cfg
->x_last_basic_block
, bb
);
4715 /* The statements in BB need to be associated with a new TREE_BLOCK.
4716 Labels need to be associated with a new label-to-block map. */
4717 memset (&d
, 0, sizeof (d
));
4718 d
.vars_to_remove
= vars_to_remove
;
4720 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4722 tree stmt
= bsi_stmt (si
);
4725 d
.from_context
= cfun
->decl
;
4726 d
.to_context
= dest_cfun
->decl
;
4727 d
.remap_decls_p
= true;
4728 d
.new_label_map
= new_label_map
;
4729 if (TREE_BLOCK (stmt
))
4730 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4732 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4734 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4736 tree label
= LABEL_EXPR_LABEL (stmt
);
4737 int uid
= LABEL_DECL_UID (label
);
4739 gcc_assert (uid
> -1);
4741 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4742 if (old_len
<= (unsigned) uid
)
4744 new_len
= 3 * uid
/ 2;
4745 VEC_safe_grow_cleared (basic_block
, gc
,
4746 cfg
->x_label_to_block_map
, new_len
);
4749 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4750 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4752 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4754 if (uid
>= dest_cfun
->last_label_uid
)
4755 dest_cfun
->last_label_uid
= uid
+ 1;
4757 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4758 TREE_OPERAND (stmt
, 0) =
4759 build_int_cst (NULL_TREE
,
4760 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4763 region
= lookup_stmt_eh_region (stmt
);
4766 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4767 remove_stmt_from_eh_region (stmt
);
4768 gimple_duplicate_stmt_histograms (dest_cfun
, stmt
, cfun
, stmt
);
4769 gimple_remove_stmt_histograms (cfun
, stmt
);
4774 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4775 the outermost EH region. Use REGION as the incoming base EH region. */
4778 find_outermost_region_in_block (struct function
*src_cfun
,
4779 basic_block bb
, int region
)
4781 block_stmt_iterator si
;
4783 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4785 tree stmt
= bsi_stmt (si
);
4788 if (TREE_CODE (stmt
) == RESX_EXPR
)
4789 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4791 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4792 if (stmt_region
> 0)
4795 region
= stmt_region
;
4796 else if (stmt_region
!= region
)
4798 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4799 gcc_assert (region
!= -1);
4808 new_label_mapper (tree decl
, void *data
)
4810 htab_t hash
= (htab_t
) data
;
4814 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4816 m
= xmalloc (sizeof (struct tree_map
));
4817 m
->hash
= DECL_UID (decl
);
4819 m
->to
= create_artificial_label ();
4820 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4822 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4823 gcc_assert (*slot
== NULL
);
4830 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4831 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4832 single basic block in the original CFG and the new basic block is
4833 returned. DEST_CFUN must not have a CFG yet.
4835 Note that the region need not be a pure SESE region. Blocks inside
4836 the region may contain calls to abort/exit. The only restriction
4837 is that ENTRY_BB should be the only entry point and it must
4840 All local variables referenced in the region are assumed to be in
4841 the corresponding BLOCK_VARS and unexpanded variable lists
4842 associated with DEST_CFUN. */
4845 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4846 basic_block exit_bb
)
4848 VEC(basic_block
,heap
) *bbs
;
4849 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4850 struct function
*saved_cfun
;
4851 int *entry_flag
, *exit_flag
, eh_offset
;
4852 unsigned i
, num_entry_edges
, num_exit_edges
;
4855 bitmap vars_to_remove
;
4856 htab_t new_label_map
;
4860 /* Collect all the blocks in the region. Manually add ENTRY_BB
4861 because it won't be added by dfs_enumerate_from. */
4862 calculate_dominance_info (CDI_DOMINATORS
);
4864 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4866 gcc_assert (entry_bb
!= exit_bb
4868 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4871 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4872 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4874 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4875 the predecessor edges to ENTRY_BB and the successor edges to
4876 EXIT_BB so that we can re-attach them to the new basic block that
4877 will replace the region. */
4878 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4879 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4880 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4882 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4884 entry_flag
[i
] = e
->flags
;
4885 entry_pred
[i
++] = e
->src
;
4891 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4892 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4893 sizeof (basic_block
));
4894 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4896 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4898 exit_flag
[i
] = e
->flags
;
4899 exit_succ
[i
++] = e
->dest
;
4910 /* Switch context to the child function to initialize DEST_FN's CFG. */
4911 gcc_assert (dest_cfun
->cfg
== NULL
);
4914 init_empty_tree_cfg ();
4916 /* Initialize EH information for the new function. */
4918 new_label_map
= NULL
;
4923 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4924 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4926 init_eh_for_function ();
4929 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4930 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4931 new_label_map
, region
, 0);
4937 /* Move blocks from BBS into DEST_CFUN. */
4938 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4939 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4940 vars_to_remove
= BITMAP_ALLOC (NULL
);
4941 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4943 /* No need to update edge counts on the last block. It has
4944 already been updated earlier when we detached the region from
4945 the original CFG. */
4946 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4947 new_label_map
, eh_offset
);
4952 htab_delete (new_label_map
);
4954 /* Remove the variables marked in VARS_TO_REMOVE from
4955 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4956 DECL_RTL in the context of CFUN. */
4957 if (!bitmap_empty_p (vars_to_remove
))
4961 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4963 tree var
= TREE_VALUE (*p
);
4964 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4966 *p
= TREE_CHAIN (*p
);
4970 p
= &TREE_CHAIN (*p
);
4974 BITMAP_FREE (vars_to_remove
);
4976 /* Rewire the entry and exit blocks. The successor to the entry
4977 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4978 the child function. Similarly, the predecessor of DEST_FN's
4979 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4980 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4981 various CFG manipulation function get to the right CFG.
4983 FIXME, this is silly. The CFG ought to become a parameter to
4986 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4988 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4991 /* Back in the original function, the SESE region has disappeared,
4992 create a new basic block in its place. */
4993 bb
= create_empty_bb (entry_pred
[0]);
4994 for (i
= 0; i
< num_entry_edges
; i
++)
4995 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4997 for (i
= 0; i
< num_exit_edges
; i
++)
4998 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
5007 free_dominance_info (CDI_DOMINATORS
);
5008 free_dominance_info (CDI_POST_DOMINATORS
);
5009 VEC_free (basic_block
, heap
, bbs
);
5015 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5018 dump_function_to_file (tree fn
, FILE *file
, int flags
)
5020 tree arg
, vars
, var
;
5021 bool ignore_topmost_bind
= false, any_var
= false;
5024 struct function
*saved_cfun
;
5026 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5028 arg
= DECL_ARGUMENTS (fn
);
5031 print_generic_expr (file
, arg
, dump_flags
);
5032 if (TREE_CHAIN (arg
))
5033 fprintf (file
, ", ");
5034 arg
= TREE_CHAIN (arg
);
5036 fprintf (file
, ")\n");
5038 if (flags
& TDF_DETAILS
)
5039 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
5040 if (flags
& TDF_RAW
)
5042 dump_node (fn
, TDF_SLIM
| flags
, file
);
5046 /* Switch CFUN to point to FN. */
5048 cfun
= DECL_STRUCT_FUNCTION (fn
);
5050 /* When GIMPLE is lowered, the variables are no longer available in
5051 BIND_EXPRs, so display them separately. */
5052 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5054 ignore_topmost_bind
= true;
5056 fprintf (file
, "{\n");
5057 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5059 var
= TREE_VALUE (vars
);
5061 print_generic_decl (file
, var
, flags
);
5062 fprintf (file
, "\n");
5068 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5070 /* Make a CFG based dump. */
5071 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5072 if (!ignore_topmost_bind
)
5073 fprintf (file
, "{\n");
5075 if (any_var
&& n_basic_blocks
)
5076 fprintf (file
, "\n");
5079 dump_generic_bb (file
, bb
, 2, flags
);
5081 fprintf (file
, "}\n");
5082 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5088 /* Make a tree based dump. */
5089 chain
= DECL_SAVED_TREE (fn
);
5091 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5093 if (ignore_topmost_bind
)
5095 chain
= BIND_EXPR_BODY (chain
);
5103 if (!ignore_topmost_bind
)
5104 fprintf (file
, "{\n");
5109 fprintf (file
, "\n");
5111 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5112 if (ignore_topmost_bind
)
5113 fprintf (file
, "}\n");
5116 fprintf (file
, "\n\n");
5123 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5126 debug_function (tree fn
, int flags
)
5128 dump_function_to_file (fn
, stderr
, flags
);
5132 /* Pretty print of the loops intermediate representation. */
5133 static void print_loop (FILE *, struct loop
*, int);
5134 static void print_pred_bbs (FILE *, basic_block bb
);
5135 static void print_succ_bbs (FILE *, basic_block bb
);
5138 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5141 print_pred_bbs (FILE *file
, basic_block bb
)
5146 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5147 fprintf (file
, "bb_%d ", e
->src
->index
);
5151 /* Print on FILE the indexes for the successors of basic_block BB. */
5154 print_succ_bbs (FILE *file
, basic_block bb
)
5159 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5160 fprintf (file
, "bb_%d ", e
->dest
->index
);
5164 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5167 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5175 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5176 memset ((void *) s_indent
, ' ', (size_t) indent
);
5177 s_indent
[indent
] = '\0';
5179 /* Print the loop's header. */
5180 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5182 /* Print the loop's body. */
5183 fprintf (file
, "%s{\n", s_indent
);
5185 if (bb
->loop_father
== loop
)
5187 /* Print the basic_block's header. */
5188 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5189 print_pred_bbs (file
, bb
);
5190 fprintf (file
, "}, succs = {");
5191 print_succ_bbs (file
, bb
);
5192 fprintf (file
, "})\n");
5194 /* Print the basic_block's body. */
5195 fprintf (file
, "%s {\n", s_indent
);
5196 tree_dump_bb (bb
, file
, indent
+ 4);
5197 fprintf (file
, "%s }\n", s_indent
);
5200 print_loop (file
, loop
->inner
, indent
+ 2);
5201 fprintf (file
, "%s}\n", s_indent
);
5202 print_loop (file
, loop
->next
, indent
);
5206 /* Follow a CFG edge from the entry point of the program, and on entry
5207 of a loop, pretty print the loop structure on FILE. */
5210 print_loop_ir (FILE *file
)
5214 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5215 if (bb
&& bb
->loop_father
)
5216 print_loop (file
, bb
->loop_father
, 0);
5220 /* Debugging loops structure at tree level. */
5223 debug_loop_ir (void)
5225 print_loop_ir (stderr
);
5229 /* Return true if BB ends with a call, possibly followed by some
5230 instructions that must stay with the call. Return false,
5234 tree_block_ends_with_call_p (basic_block bb
)
5236 block_stmt_iterator bsi
= bsi_last (bb
);
5237 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5241 /* Return true if BB ends with a conditional branch. Return false,
5245 tree_block_ends_with_condjump_p (basic_block bb
)
5247 tree stmt
= last_stmt (bb
);
5248 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5252 /* Return true if we need to add fake edge to exit at statement T.
5253 Helper function for tree_flow_call_edges_add. */
5256 need_fake_edge_p (tree t
)
5260 /* NORETURN and LONGJMP calls already have an edge to exit.
5261 CONST and PURE calls do not need one.
5262 We don't currently check for CONST and PURE here, although
5263 it would be a good idea, because those attributes are
5264 figured out from the RTL in mark_constant_function, and
5265 the counter incrementation code from -fprofile-arcs
5266 leads to different results from -fbranch-probabilities. */
5267 call
= get_call_expr_in (t
);
5269 && !(call_expr_flags (call
) & ECF_NORETURN
))
5272 if (TREE_CODE (t
) == ASM_EXPR
5273 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5280 /* Add fake edges to the function exit for any non constant and non
5281 noreturn calls, volatile inline assembly in the bitmap of blocks
5282 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5283 the number of blocks that were split.
5285 The goal is to expose cases in which entering a basic block does
5286 not imply that all subsequent instructions must be executed. */
5289 tree_flow_call_edges_add (sbitmap blocks
)
5292 int blocks_split
= 0;
5293 int last_bb
= last_basic_block
;
5294 bool check_last_block
= false;
5296 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5300 check_last_block
= true;
5302 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5304 /* In the last basic block, before epilogue generation, there will be
5305 a fallthru edge to EXIT. Special care is required if the last insn
5306 of the last basic block is a call because make_edge folds duplicate
5307 edges, which would result in the fallthru edge also being marked
5308 fake, which would result in the fallthru edge being removed by
5309 remove_fake_edges, which would result in an invalid CFG.
5311 Moreover, we can't elide the outgoing fake edge, since the block
5312 profiler needs to take this into account in order to solve the minimal
5313 spanning tree in the case that the call doesn't return.
5315 Handle this by adding a dummy instruction in a new last basic block. */
5316 if (check_last_block
)
5318 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5319 block_stmt_iterator bsi
= bsi_last (bb
);
5321 if (!bsi_end_p (bsi
))
5324 if (t
&& need_fake_edge_p (t
))
5328 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5331 bsi_insert_on_edge (e
, build_empty_stmt ());
5332 bsi_commit_edge_inserts ();
5337 /* Now add fake edges to the function exit for any non constant
5338 calls since there is no way that we can determine if they will
5340 for (i
= 0; i
< last_bb
; i
++)
5342 basic_block bb
= BASIC_BLOCK (i
);
5343 block_stmt_iterator bsi
;
5344 tree stmt
, last_stmt
;
5349 if (blocks
&& !TEST_BIT (blocks
, i
))
5352 bsi
= bsi_last (bb
);
5353 if (!bsi_end_p (bsi
))
5355 last_stmt
= bsi_stmt (bsi
);
5358 stmt
= bsi_stmt (bsi
);
5359 if (need_fake_edge_p (stmt
))
5362 /* The handling above of the final block before the
5363 epilogue should be enough to verify that there is
5364 no edge to the exit block in CFG already.
5365 Calling make_edge in such case would cause us to
5366 mark that edge as fake and remove it later. */
5367 #ifdef ENABLE_CHECKING
5368 if (stmt
== last_stmt
)
5370 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5371 gcc_assert (e
== NULL
);
5375 /* Note that the following may create a new basic block
5376 and renumber the existing basic blocks. */
5377 if (stmt
!= last_stmt
)
5379 e
= split_block (bb
, stmt
);
5383 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5387 while (!bsi_end_p (bsi
));
5392 verify_flow_info ();
5394 return blocks_split
;
5397 /* Purge dead abnormal call edges from basic block BB. */
5400 tree_purge_dead_abnormal_call_edges (basic_block bb
)
5402 bool changed
= tree_purge_dead_eh_edges (bb
);
5404 if (current_function_has_nonlocal_label
)
5406 tree stmt
= last_stmt (bb
);
5410 if (!(stmt
&& tree_can_make_abnormal_goto (stmt
)))
5411 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5413 if (e
->flags
& EDGE_ABNORMAL
)
5422 /* See tree_purge_dead_eh_edges below. */
5424 free_dominance_info (CDI_DOMINATORS
);
5430 /* Purge dead EH edges from basic block BB. */
5433 tree_purge_dead_eh_edges (basic_block bb
)
5435 bool changed
= false;
5438 tree stmt
= last_stmt (bb
);
5440 if (stmt
&& tree_can_throw_internal (stmt
))
5443 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5445 if (e
->flags
& EDGE_EH
)
5454 /* Removal of dead EH edges might change dominators of not
5455 just immediate successors. E.g. when bb1 is changed so that
5456 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5457 eh edges purged by this function in:
5469 idom(bb5) must be recomputed. For now just free the dominance
5472 free_dominance_info (CDI_DOMINATORS
);
5478 tree_purge_all_dead_eh_edges (bitmap blocks
)
5480 bool changed
= false;
5484 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5486 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5492 /* This function is called whenever a new edge is created or
5496 tree_execute_on_growing_pred (edge e
)
5498 basic_block bb
= e
->dest
;
5501 reserve_phi_args_for_new_edge (bb
);
5504 /* This function is called immediately before edge E is removed from
5505 the edge vector E->dest->preds. */
5508 tree_execute_on_shrinking_pred (edge e
)
5510 if (phi_nodes (e
->dest
))
5511 remove_phi_args (e
);
5514 /*---------------------------------------------------------------------------
5515 Helper functions for Loop versioning
5516 ---------------------------------------------------------------------------*/
5518 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5519 of 'first'. Both of them are dominated by 'new_head' basic block. When
5520 'new_head' was created by 'second's incoming edge it received phi arguments
5521 on the edge by split_edge(). Later, additional edge 'e' was created to
5522 connect 'new_head' and 'first'. Now this routine adds phi args on this
5523 additional edge 'e' that new_head to second edge received as part of edge
5528 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5529 basic_block new_head
, edge e
)
5532 edge e2
= find_edge (new_head
, second
);
5534 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5535 edge, we should always have an edge from NEW_HEAD to SECOND. */
5536 gcc_assert (e2
!= NULL
);
5538 /* Browse all 'second' basic block phi nodes and add phi args to
5539 edge 'e' for 'first' head. PHI args are always in correct order. */
5541 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5543 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5545 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5546 add_phi_arg (phi1
, def
, e
);
5550 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5551 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5552 the destination of the ELSE part. */
5554 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5555 basic_block cond_bb
, void *cond_e
)
5557 block_stmt_iterator bsi
;
5558 tree goto1
= NULL_TREE
;
5559 tree goto2
= NULL_TREE
;
5560 tree new_cond_expr
= NULL_TREE
;
5561 tree cond_expr
= (tree
) cond_e
;
5564 /* Build new conditional expr */
5565 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5566 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5567 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5569 /* Add new cond in cond_bb. */
5570 bsi
= bsi_start (cond_bb
);
5571 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5572 /* Adjust edges appropriately to connect new head with first head
5573 as well as second head. */
5574 e0
= single_succ_edge (cond_bb
);
5575 e0
->flags
&= ~EDGE_FALLTHRU
;
5576 e0
->flags
|= EDGE_FALSE_VALUE
;
5579 struct cfg_hooks tree_cfg_hooks
= {
5581 tree_verify_flow_info
,
5582 tree_dump_bb
, /* dump_bb */
5583 create_bb
, /* create_basic_block */
5584 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5585 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5586 remove_bb
, /* delete_basic_block */
5587 tree_split_block
, /* split_block */
5588 tree_move_block_after
, /* move_block_after */
5589 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5590 tree_merge_blocks
, /* merge_blocks */
5591 tree_predict_edge
, /* predict_edge */
5592 tree_predicted_by_p
, /* predicted_by_p */
5593 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5594 tree_duplicate_bb
, /* duplicate_block */
5595 tree_split_edge
, /* split_edge */
5596 tree_make_forwarder_block
, /* make_forward_block */
5597 NULL
, /* tidy_fallthru_edge */
5598 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5599 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5600 tree_flow_call_edges_add
, /* flow_call_edges_add */
5601 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5602 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5603 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5604 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5605 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5606 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5607 flush_pending_stmts
/* flush_pending_stmts */
5611 /* Split all critical edges. */
5614 split_critical_edges (void)
5620 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5621 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5622 mappings around the calls to split_edge. */
5623 start_recording_case_labels ();
5626 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5627 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5632 end_recording_case_labels ();
5636 struct tree_opt_pass pass_split_crit_edges
=
5638 "crited", /* name */
5640 split_critical_edges
, /* execute */
5643 0, /* static_pass_number */
5644 TV_TREE_SPLIT_EDGES
, /* tv_id */
5645 PROP_cfg
, /* properties required */
5646 PROP_no_crit_edges
, /* properties_provided */
5647 0, /* properties_destroyed */
5648 0, /* todo_flags_start */
5649 TODO_dump_func
, /* todo_flags_finish */
5654 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5655 a temporary, make sure and register it to be renamed if necessary,
5656 and finally return the temporary. Put the statements to compute
5657 EXP before the current statement in BSI. */
5660 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5662 tree t
, new_stmt
, orig_stmt
;
5664 if (is_gimple_val (exp
))
5667 t
= make_rename_temp (type
, NULL
);
5668 new_stmt
= build2_gimple (GIMPLE_MODIFY_STMT
, t
, exp
);
5670 orig_stmt
= bsi_stmt (*bsi
);
5671 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5672 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5674 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5675 if (gimple_in_ssa_p (cfun
))
5676 mark_symbols_for_renaming (new_stmt
);
5681 /* Build a ternary operation and gimplify it. Emit code before BSI.
5682 Return the gimple_val holding the result. */
5685 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5686 tree type
, tree a
, tree b
, tree c
)
5690 ret
= fold_build3 (code
, type
, a
, b
, c
);
5693 return gimplify_val (bsi
, type
, ret
);
5696 /* Build a binary operation and gimplify it. Emit code before BSI.
5697 Return the gimple_val holding the result. */
5700 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5701 tree type
, tree a
, tree b
)
5705 ret
= fold_build2 (code
, type
, a
, b
);
5708 return gimplify_val (bsi
, type
, ret
);
5711 /* Build a unary operation and gimplify it. Emit code before BSI.
5712 Return the gimple_val holding the result. */
5715 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5720 ret
= fold_build1 (code
, type
, a
);
5723 return gimplify_val (bsi
, type
, ret
);
5728 /* Emit return warnings. */
5731 execute_warn_function_return (void)
5733 #ifdef USE_MAPPED_LOCATION
5734 source_location location
;
5742 /* If we have a path to EXIT, then we do return. */
5743 if (TREE_THIS_VOLATILE (cfun
->decl
)
5744 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5746 #ifdef USE_MAPPED_LOCATION
5747 location
= UNKNOWN_LOCATION
;
5751 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5753 last
= last_stmt (e
->src
);
5754 if (TREE_CODE (last
) == RETURN_EXPR
5755 #ifdef USE_MAPPED_LOCATION
5756 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5758 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5762 #ifdef USE_MAPPED_LOCATION
5763 if (location
== UNKNOWN_LOCATION
)
5764 location
= cfun
->function_end_locus
;
5765 warning (0, "%H%<noreturn%> function does return", &location
);
5768 locus
= &cfun
->function_end_locus
;
5769 warning (0, "%H%<noreturn%> function does return", locus
);
5773 /* If we see "return;" in some basic block, then we do reach the end
5774 without returning a value. */
5775 else if (warn_return_type
5776 && !TREE_NO_WARNING (cfun
->decl
)
5777 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5778 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5780 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5782 tree last
= last_stmt (e
->src
);
5783 if (TREE_CODE (last
) == RETURN_EXPR
5784 && TREE_OPERAND (last
, 0) == NULL
5785 && !TREE_NO_WARNING (last
))
5787 #ifdef USE_MAPPED_LOCATION
5788 location
= EXPR_LOCATION (last
);
5789 if (location
== UNKNOWN_LOCATION
)
5790 location
= cfun
->function_end_locus
;
5791 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5793 locus
= EXPR_LOCUS (last
);
5795 locus
= &cfun
->function_end_locus
;
5796 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5798 TREE_NO_WARNING (cfun
->decl
) = 1;
5807 /* Given a basic block B which ends with a conditional and has
5808 precisely two successors, determine which of the edges is taken if
5809 the conditional is true and which is taken if the conditional is
5810 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5813 extract_true_false_edges_from_block (basic_block b
,
5817 edge e
= EDGE_SUCC (b
, 0);
5819 if (e
->flags
& EDGE_TRUE_VALUE
)
5822 *false_edge
= EDGE_SUCC (b
, 1);
5827 *true_edge
= EDGE_SUCC (b
, 1);
5831 struct tree_opt_pass pass_warn_function_return
=
5835 execute_warn_function_return
, /* execute */
5838 0, /* static_pass_number */
5840 PROP_cfg
, /* properties_required */
5841 0, /* properties_provided */
5842 0, /* properties_destroyed */
5843 0, /* todo_flags_start */
5844 0, /* todo_flags_finish */
5848 /* Emit noreturn warnings. */
5851 execute_warn_function_noreturn (void)
5853 if (warn_missing_noreturn
5854 && !TREE_THIS_VOLATILE (cfun
->decl
)
5855 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5856 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5857 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5858 "for attribute %<noreturn%>",
5863 struct tree_opt_pass pass_warn_function_noreturn
=
5867 execute_warn_function_noreturn
, /* execute */
5870 0, /* static_pass_number */
5872 PROP_cfg
, /* properties_required */
5873 0, /* properties_provided */
5874 0, /* properties_destroyed */
5875 0, /* todo_flags_start */
5876 0, /* todo_flags_finish */