1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to
20 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21 Boston, MA 02110-1301, USA. */
25 #include "coretypes.h"
30 #include "hard-reg-set.h"
31 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
48 #include "tree-ssa-propagate.h"
50 /* This file contains functions for building the Control Flow Graph (CFG)
51 for a function tree. */
53 /* Local declarations. */
55 /* Initial capacity for the basic block array. */
56 static const int initial_cfg_capacity
= 20;
58 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
59 which use a particular edge. The CASE_LABEL_EXPRs are chained together
60 via their TREE_CHAIN field, which we clear after we're done with the
61 hash table to prevent problems with duplication of SWITCH_EXPRs.
63 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
64 update the case vector in response to edge redirections.
66 Right now this table is set up and torn down at key points in the
67 compilation process. It would be nice if we could make the table
68 more persistent. The key is getting notification of changes to
69 the CFG (particularly edge removal, creation and redirection). */
71 struct edge_to_cases_elt
73 /* The edge itself. Necessary for hashing and equality tests. */
76 /* The case labels associated with this edge. We link these up via
77 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
78 when we destroy the hash table. This prevents problems when copying
83 static htab_t edge_to_cases
;
88 long num_merged_labels
;
91 static struct cfg_stats_d cfg_stats
;
93 /* Nonzero if we found a computed goto while building basic blocks. */
94 static bool found_computed_goto
;
96 /* Basic blocks and flowgraphs. */
97 static basic_block
create_bb (void *, void *, basic_block
);
98 static void make_blocks (tree
);
99 static void factor_computed_gotos (void);
102 static void make_edges (void);
103 static void make_cond_expr_edges (basic_block
);
104 static void make_switch_expr_edges (basic_block
);
105 static void make_goto_expr_edges (basic_block
);
106 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
107 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
108 static unsigned int split_critical_edges (void);
110 /* Various helpers. */
111 static inline bool stmt_starts_bb_p (tree
, tree
);
112 static int tree_verify_flow_info (void);
113 static void tree_make_forwarder_block (edge
);
114 static void tree_cfg2vcg (FILE *);
115 static inline void change_bb_for_stmt (tree t
, basic_block bb
);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block
, basic_block
);
119 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
120 static void remove_bb (basic_block
);
121 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
122 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
123 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
124 static tree
find_case_label_for_value (tree
, tree
);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status
= PROFILE_ABSENT
;
132 n_basic_blocks
= NUM_FIXED_BLOCKS
;
133 last_basic_block
= NUM_FIXED_BLOCKS
;
134 basic_block_info
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
135 VEC_safe_grow (basic_block
, gc
, basic_block_info
, initial_cfg_capacity
);
136 memset (VEC_address (basic_block
, basic_block_info
), 0,
137 sizeof (basic_block
) * initial_cfg_capacity
);
139 /* Build a mapping of labels to their associated blocks. */
140 label_to_block_map
= VEC_alloc (basic_block
, gc
, initial_cfg_capacity
);
141 VEC_safe_grow (basic_block
, gc
, label_to_block_map
, initial_cfg_capacity
);
142 memset (VEC_address (basic_block
, label_to_block_map
),
143 0, sizeof (basic_block
) * initial_cfg_capacity
);
145 SET_BASIC_BLOCK (ENTRY_BLOCK
, ENTRY_BLOCK_PTR
);
146 SET_BASIC_BLOCK (EXIT_BLOCK
, EXIT_BLOCK_PTR
);
147 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
148 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
151 /*---------------------------------------------------------------------------
153 ---------------------------------------------------------------------------*/
155 /* Entry point to the CFG builder for trees. TP points to the list of
156 statements to be added to the flowgraph. */
159 build_tree_cfg (tree
*tp
)
161 /* Register specific tree functions. */
162 tree_register_cfg_hooks ();
164 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
166 init_empty_tree_cfg ();
168 found_computed_goto
= 0;
171 /* Computed gotos are hell to deal with, especially if there are
172 lots of them with a large number of destinations. So we factor
173 them to a common computed goto location before we build the
174 edge list. After we convert back to normal form, we will un-factor
175 the computed gotos since factoring introduces an unwanted jump. */
176 if (found_computed_goto
)
177 factor_computed_gotos ();
179 /* Make sure there is always at least one block, even if it's empty. */
180 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
181 create_empty_bb (ENTRY_BLOCK_PTR
);
183 /* Adjust the size of the array. */
184 if (VEC_length (basic_block
, basic_block_info
) < (size_t) n_basic_blocks
)
186 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
188 VEC_safe_grow (basic_block
, gc
, basic_block_info
, n_basic_blocks
);
189 p
= VEC_address (basic_block
, basic_block_info
);
190 memset (&p
[old_size
], 0,
191 sizeof (basic_block
) * (n_basic_blocks
- old_size
));
194 /* To speed up statement iterator walks, we first purge dead labels. */
195 cleanup_dead_labels ();
197 /* Group case nodes to reduce the number of edges.
198 We do this after cleaning up dead labels because otherwise we miss
199 a lot of obvious case merging opportunities. */
200 group_case_labels ();
202 /* Create the edges of the flowgraph. */
205 /* Debugging dumps. */
207 /* Write the flowgraph to a VCG file. */
209 int local_dump_flags
;
210 FILE *vcg_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
213 tree_cfg2vcg (vcg_file
);
214 dump_end (TDI_vcg
, vcg_file
);
218 #ifdef ENABLE_CHECKING
222 /* Dump a textual representation of the flowgraph. */
224 dump_tree_cfg (dump_file
, dump_flags
);
228 execute_build_cfg (void)
230 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
234 struct tree_opt_pass pass_build_cfg
=
238 execute_build_cfg
, /* execute */
241 0, /* static_pass_number */
242 TV_TREE_CFG
, /* tv_id */
243 PROP_gimple_leh
, /* properties_required */
244 PROP_cfg
, /* properties_provided */
245 0, /* properties_destroyed */
246 0, /* todo_flags_start */
247 TODO_verify_stmts
, /* todo_flags_finish */
251 /* Search the CFG for any computed gotos. If found, factor them to a
252 common computed goto site. Also record the location of that site so
253 that we can un-factor the gotos after we have converted back to
257 factor_computed_gotos (void)
260 tree factored_label_decl
= NULL
;
262 tree factored_computed_goto_label
= NULL
;
263 tree factored_computed_goto
= NULL
;
265 /* We know there are one or more computed gotos in this function.
266 Examine the last statement in each basic block to see if the block
267 ends with a computed goto. */
271 block_stmt_iterator bsi
= bsi_last (bb
);
276 last
= bsi_stmt (bsi
);
278 /* Ignore the computed goto we create when we factor the original
280 if (last
== factored_computed_goto
)
283 /* If the last statement is a computed goto, factor it. */
284 if (computed_goto_p (last
))
288 /* The first time we find a computed goto we need to create
289 the factored goto block and the variable each original
290 computed goto will use for their goto destination. */
291 if (! factored_computed_goto
)
293 basic_block new_bb
= create_empty_bb (bb
);
294 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
296 /* Create the destination of the factored goto. Each original
297 computed goto will put its desired destination into this
298 variable and jump to the label we create immediately
300 var
= create_tmp_var (ptr_type_node
, "gotovar");
302 /* Build a label for the new block which will contain the
303 factored computed goto. */
304 factored_label_decl
= create_artificial_label ();
305 factored_computed_goto_label
306 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
307 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
310 /* Build our new computed goto. */
311 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
312 bsi_insert_after (&new_bsi
, factored_computed_goto
,
316 /* Copy the original computed goto's destination into VAR. */
317 assignment
= build2_gimple (GIMPLE_MODIFY_STMT
,
318 var
, GOTO_DESTINATION (last
));
319 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
321 /* And re-vector the computed goto to the new destination. */
322 GOTO_DESTINATION (last
) = factored_label_decl
;
328 /* Build a flowgraph for the statement_list STMT_LIST. */
331 make_blocks (tree stmt_list
)
333 tree_stmt_iterator i
= tsi_start (stmt_list
);
335 bool start_new_block
= true;
336 bool first_stmt_of_list
= true;
337 basic_block bb
= ENTRY_BLOCK_PTR
;
339 while (!tsi_end_p (i
))
346 /* If the statement starts a new basic block or if we have determined
347 in a previous pass that we need to create a new block for STMT, do
349 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
351 if (!first_stmt_of_list
)
352 stmt_list
= tsi_split_statement_list_before (&i
);
353 bb
= create_basic_block (stmt_list
, NULL
, bb
);
354 start_new_block
= false;
357 /* Now add STMT to BB and create the subgraphs for special statement
359 set_bb_for_stmt (stmt
, bb
);
361 if (computed_goto_p (stmt
))
362 found_computed_goto
= true;
364 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
366 if (stmt_ends_bb_p (stmt
))
367 start_new_block
= true;
370 first_stmt_of_list
= false;
375 /* Create and return a new empty basic block after bb AFTER. */
378 create_bb (void *h
, void *e
, basic_block after
)
384 /* Create and initialize a new basic block. Since alloc_block uses
385 ggc_alloc_cleared to allocate a basic block, we do not have to
386 clear the newly allocated basic block here. */
389 bb
->index
= last_basic_block
;
391 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
393 /* Add the new block to the linked list of blocks. */
394 link_block (bb
, after
);
396 /* Grow the basic block array if needed. */
397 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
399 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
400 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
402 VEC_safe_grow (basic_block
, gc
, basic_block_info
, new_size
);
403 p
= VEC_address (basic_block
, basic_block_info
);
404 memset (&p
[old_size
], 0, sizeof (basic_block
) * (new_size
- old_size
));
407 /* Add the newly created block to the array. */
408 SET_BASIC_BLOCK (last_basic_block
, bb
);
417 /*---------------------------------------------------------------------------
419 ---------------------------------------------------------------------------*/
421 /* Fold COND_EXPR_COND of each COND_EXPR. */
424 fold_cond_expr_cond (void)
430 tree stmt
= last_stmt (bb
);
433 && TREE_CODE (stmt
) == COND_EXPR
)
435 tree cond
= fold (COND_EXPR_COND (stmt
));
436 if (integer_zerop (cond
))
437 COND_EXPR_COND (stmt
) = boolean_false_node
;
438 else if (integer_onep (cond
))
439 COND_EXPR_COND (stmt
) = boolean_true_node
;
444 /* Join all the blocks in the flowgraph. */
450 struct omp_region
*cur_region
= NULL
;
452 /* Create an edge from entry to the first block with executable
454 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
456 /* Traverse the basic block array placing edges. */
459 tree last
= last_stmt (bb
);
464 enum tree_code code
= TREE_CODE (last
);
468 make_goto_expr_edges (bb
);
472 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
476 make_cond_expr_edges (bb
);
480 make_switch_expr_edges (bb
);
484 make_eh_edges (last
);
489 /* If this function receives a nonlocal goto, then we need to
490 make edges from this call site to all the nonlocal goto
492 if (tree_can_make_abnormal_goto (last
))
493 make_abnormal_goto_edges (bb
, true);
495 /* If this statement has reachable exception handlers, then
496 create abnormal edges to them. */
497 make_eh_edges (last
);
499 /* Some calls are known not to return. */
500 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
506 case GIMPLE_MODIFY_STMT
:
507 if (is_ctrl_altering_stmt (last
))
509 /* A GIMPLE_MODIFY_STMT may have a CALL_EXPR on its RHS and
510 the CALL_EXPR may have an abnormal edge. Search the RHS
511 for this case and create any required edges. */
512 if (tree_can_make_abnormal_goto (last
))
513 make_abnormal_goto_edges (bb
, true);
515 make_eh_edges (last
);
527 cur_region
= new_omp_region (bb
, code
, cur_region
);
532 cur_region
= new_omp_region (bb
, code
, cur_region
);
537 /* In the case of an OMP_SECTION, the edge will go somewhere
538 other than the next block. This will be created later. */
539 cur_region
->exit
= bb
;
540 fallthru
= cur_region
->type
!= OMP_SECTION
;
541 cur_region
= cur_region
->outer
;
545 cur_region
->cont
= bb
;
546 switch (cur_region
->type
)
549 /* ??? Technically there should be a some sort of loopback
550 edge here, but it goes to a block that doesn't exist yet,
551 and without it, updating the ssa form would be a real
552 bear. Fortunately, we don't yet do ssa before expanding
557 /* Wire up the edges into and out of the nested sections. */
558 /* ??? Similarly wrt loopback. */
560 struct omp_region
*i
;
561 for (i
= cur_region
->inner
; i
; i
= i
->next
)
563 gcc_assert (i
->type
== OMP_SECTION
);
564 make_edge (cur_region
->entry
, i
->entry
, 0);
565 make_edge (i
->exit
, bb
, EDGE_FALLTHRU
);
577 gcc_assert (!stmt_ends_bb_p (last
));
585 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
591 /* Fold COND_EXPR_COND of each COND_EXPR. */
592 fold_cond_expr_cond ();
594 /* Clean up the graph and warn for unreachable code. */
599 /* Create the edges for a COND_EXPR starting at block BB.
600 At this point, both clauses must contain only simple gotos. */
603 make_cond_expr_edges (basic_block bb
)
605 tree entry
= last_stmt (bb
);
606 basic_block then_bb
, else_bb
;
607 tree then_label
, else_label
;
611 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
613 /* Entry basic blocks for each component. */
614 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
615 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
616 then_bb
= label_to_block (then_label
);
617 else_bb
= label_to_block (else_label
);
619 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
620 #ifdef USE_MAPPED_LOCATION
621 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
623 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
625 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
628 #ifdef USE_MAPPED_LOCATION
629 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
631 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
636 /* Hashing routine for EDGE_TO_CASES. */
639 edge_to_cases_hash (const void *p
)
641 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
643 /* Hash on the edge itself (which is a pointer). */
644 return htab_hash_pointer (e
);
647 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
648 for equality is just a pointer comparison. */
651 edge_to_cases_eq (const void *p1
, const void *p2
)
653 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
654 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
659 /* Called for each element in the hash table (P) as we delete the
660 edge to cases hash table.
662 Clear all the TREE_CHAINs to prevent problems with copying of
663 SWITCH_EXPRs and structure sharing rules, then free the hash table
667 edge_to_cases_cleanup (void *p
)
669 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
672 for (t
= elt
->case_labels
; t
; t
= next
)
674 next
= TREE_CHAIN (t
);
675 TREE_CHAIN (t
) = NULL
;
680 /* Start recording information mapping edges to case labels. */
683 start_recording_case_labels (void)
685 gcc_assert (edge_to_cases
== NULL
);
687 edge_to_cases
= htab_create (37,
690 edge_to_cases_cleanup
);
693 /* Return nonzero if we are recording information for case labels. */
696 recording_case_labels_p (void)
698 return (edge_to_cases
!= NULL
);
701 /* Stop recording information mapping edges to case labels and
702 remove any information we have recorded. */
704 end_recording_case_labels (void)
706 htab_delete (edge_to_cases
);
707 edge_to_cases
= NULL
;
710 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
713 record_switch_edge (edge e
, tree case_label
)
715 struct edge_to_cases_elt
*elt
;
718 /* Build a hash table element so we can see if E is already
720 elt
= XNEW (struct edge_to_cases_elt
);
722 elt
->case_labels
= case_label
;
724 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
728 /* E was not in the hash table. Install E into the hash table. */
733 /* E was already in the hash table. Free ELT as we do not need it
737 /* Get the entry stored in the hash table. */
738 elt
= (struct edge_to_cases_elt
*) *slot
;
740 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
741 TREE_CHAIN (case_label
) = elt
->case_labels
;
742 elt
->case_labels
= case_label
;
746 /* If we are inside a {start,end}_recording_cases block, then return
747 a chain of CASE_LABEL_EXPRs from T which reference E.
749 Otherwise return NULL. */
752 get_cases_for_edge (edge e
, tree t
)
754 struct edge_to_cases_elt elt
, *elt_p
;
759 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
760 chains available. Return NULL so the caller can detect this case. */
761 if (!recording_case_labels_p ())
766 elt
.case_labels
= NULL
;
767 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
771 elt_p
= (struct edge_to_cases_elt
*)*slot
;
772 return elt_p
->case_labels
;
775 /* If we did not find E in the hash table, then this must be the first
776 time we have been queried for information about E & T. Add all the
777 elements from T to the hash table then perform the query again. */
779 vec
= SWITCH_LABELS (t
);
780 n
= TREE_VEC_LENGTH (vec
);
781 for (i
= 0; i
< n
; i
++)
783 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
784 basic_block label_bb
= label_to_block (lab
);
785 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
790 /* Create the edges for a SWITCH_EXPR starting at block BB.
791 At this point, the switch body has been lowered and the
792 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
795 make_switch_expr_edges (basic_block bb
)
797 tree entry
= last_stmt (bb
);
801 vec
= SWITCH_LABELS (entry
);
802 n
= TREE_VEC_LENGTH (vec
);
804 for (i
= 0; i
< n
; ++i
)
806 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
807 basic_block label_bb
= label_to_block (lab
);
808 make_edge (bb
, label_bb
, 0);
813 /* Return the basic block holding label DEST. */
816 label_to_block_fn (struct function
*ifun
, tree dest
)
818 int uid
= LABEL_DECL_UID (dest
);
820 /* We would die hard when faced by an undefined label. Emit a label to
821 the very first basic block. This will hopefully make even the dataflow
822 and undefined variable warnings quite right. */
823 if ((errorcount
|| sorrycount
) && uid
< 0)
825 block_stmt_iterator bsi
=
826 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
829 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
830 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
831 uid
= LABEL_DECL_UID (dest
);
833 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
834 <= (unsigned int) uid
)
836 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
839 /* Create edges for an abnormal goto statement at block BB. If FOR_CALL
840 is true, the source statement is a CALL_EXPR instead of a GOTO_EXPR. */
843 make_abnormal_goto_edges (basic_block bb
, bool for_call
)
845 basic_block target_bb
;
846 block_stmt_iterator bsi
;
848 FOR_EACH_BB (target_bb
)
849 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
851 tree target
= bsi_stmt (bsi
);
853 if (TREE_CODE (target
) != LABEL_EXPR
)
856 target
= LABEL_EXPR_LABEL (target
);
858 /* Make an edge to every label block that has been marked as a
859 potential target for a computed goto or a non-local goto. */
860 if ((FORCED_LABEL (target
) && !for_call
)
861 || (DECL_NONLOCAL (target
) && for_call
))
863 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
869 /* Create edges for a goto statement at block BB. */
872 make_goto_expr_edges (basic_block bb
)
874 block_stmt_iterator last
= bsi_last (bb
);
875 tree goto_t
= bsi_stmt (last
);
877 /* A simple GOTO creates normal edges. */
878 if (simple_goto_p (goto_t
))
880 tree dest
= GOTO_DESTINATION (goto_t
);
881 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
882 #ifdef USE_MAPPED_LOCATION
883 e
->goto_locus
= EXPR_LOCATION (goto_t
);
885 e
->goto_locus
= EXPR_LOCUS (goto_t
);
887 bsi_remove (&last
, true);
891 /* A computed GOTO creates abnormal edges. */
892 make_abnormal_goto_edges (bb
, false);
896 /*---------------------------------------------------------------------------
898 ---------------------------------------------------------------------------*/
900 /* Cleanup useless labels in basic blocks. This is something we wish
901 to do early because it allows us to group case labels before creating
902 the edges for the CFG, and it speeds up block statement iterators in
904 We only run this pass once, running it more than once is probably not
907 /* A map from basic block index to the leading label of that block. */
908 static tree
*label_for_bb
;
910 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
912 update_eh_label (struct eh_region
*region
)
914 tree old_label
= get_eh_region_tree_label (region
);
918 basic_block bb
= label_to_block (old_label
);
920 /* ??? After optimizing, there may be EH regions with labels
921 that have already been removed from the function body, so
922 there is no basic block for them. */
926 new_label
= label_for_bb
[bb
->index
];
927 set_eh_region_tree_label (region
, new_label
);
931 /* Given LABEL return the first label in the same basic block. */
933 main_block_label (tree label
)
935 basic_block bb
= label_to_block (label
);
937 /* label_to_block possibly inserted undefined label into the chain. */
938 if (!label_for_bb
[bb
->index
])
939 label_for_bb
[bb
->index
] = label
;
940 return label_for_bb
[bb
->index
];
943 /* Cleanup redundant labels. This is a three-step process:
944 1) Find the leading label for each block.
945 2) Redirect all references to labels to the leading labels.
946 3) Cleanup all useless labels. */
949 cleanup_dead_labels (void)
952 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
954 /* Find a suitable label for each block. We use the first user-defined
955 label if there is one, or otherwise just the first label we see. */
958 block_stmt_iterator i
;
960 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
962 tree label
, stmt
= bsi_stmt (i
);
964 if (TREE_CODE (stmt
) != LABEL_EXPR
)
967 label
= LABEL_EXPR_LABEL (stmt
);
969 /* If we have not yet seen a label for the current block,
970 remember this one and see if there are more labels. */
971 if (! label_for_bb
[bb
->index
])
973 label_for_bb
[bb
->index
] = label
;
977 /* If we did see a label for the current block already, but it
978 is an artificially created label, replace it if the current
979 label is a user defined label. */
980 if (! DECL_ARTIFICIAL (label
)
981 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
983 label_for_bb
[bb
->index
] = label
;
989 /* Now redirect all jumps/branches to the selected label.
990 First do so for each block ending in a control statement. */
993 tree stmt
= last_stmt (bb
);
997 switch (TREE_CODE (stmt
))
1001 tree true_branch
, false_branch
;
1003 true_branch
= COND_EXPR_THEN (stmt
);
1004 false_branch
= COND_EXPR_ELSE (stmt
);
1006 GOTO_DESTINATION (true_branch
)
1007 = main_block_label (GOTO_DESTINATION (true_branch
));
1008 GOTO_DESTINATION (false_branch
)
1009 = main_block_label (GOTO_DESTINATION (false_branch
));
1017 tree vec
= SWITCH_LABELS (stmt
);
1018 size_t n
= TREE_VEC_LENGTH (vec
);
1020 /* Replace all destination labels. */
1021 for (i
= 0; i
< n
; ++i
)
1023 tree elt
= TREE_VEC_ELT (vec
, i
);
1024 tree label
= main_block_label (CASE_LABEL (elt
));
1025 CASE_LABEL (elt
) = label
;
1030 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1031 remove them until after we've created the CFG edges. */
1033 if (! computed_goto_p (stmt
))
1035 GOTO_DESTINATION (stmt
)
1036 = main_block_label (GOTO_DESTINATION (stmt
));
1045 for_each_eh_region (update_eh_label
);
1047 /* Finally, purge dead labels. All user-defined labels and labels that
1048 can be the target of non-local gotos and labels which have their
1049 address taken are preserved. */
1052 block_stmt_iterator i
;
1053 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1055 if (! label_for_this_bb
)
1058 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1060 tree label
, stmt
= bsi_stmt (i
);
1062 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1065 label
= LABEL_EXPR_LABEL (stmt
);
1067 if (label
== label_for_this_bb
1068 || ! DECL_ARTIFICIAL (label
)
1069 || DECL_NONLOCAL (label
)
1070 || FORCED_LABEL (label
))
1073 bsi_remove (&i
, true);
1077 free (label_for_bb
);
1080 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1081 and scan the sorted vector of cases. Combine the ones jumping to the
1083 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1086 group_case_labels (void)
1092 tree stmt
= last_stmt (bb
);
1093 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1095 tree labels
= SWITCH_LABELS (stmt
);
1096 int old_size
= TREE_VEC_LENGTH (labels
);
1097 int i
, j
, new_size
= old_size
;
1098 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1101 /* The default label is always the last case in a switch
1102 statement after gimplification. */
1103 default_label
= CASE_LABEL (default_case
);
1105 /* Look for possible opportunities to merge cases.
1106 Ignore the last element of the label vector because it
1107 must be the default case. */
1109 while (i
< old_size
- 1)
1111 tree base_case
, base_label
, base_high
;
1112 base_case
= TREE_VEC_ELT (labels
, i
);
1114 gcc_assert (base_case
);
1115 base_label
= CASE_LABEL (base_case
);
1117 /* Discard cases that have the same destination as the
1119 if (base_label
== default_label
)
1121 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1127 base_high
= CASE_HIGH (base_case
) ?
1128 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1130 /* Try to merge case labels. Break out when we reach the end
1131 of the label vector or when we cannot merge the next case
1132 label with the current one. */
1133 while (i
< old_size
- 1)
1135 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1136 tree merge_label
= CASE_LABEL (merge_case
);
1137 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1138 integer_one_node
, 1);
1140 /* Merge the cases if they jump to the same place,
1141 and their ranges are consecutive. */
1142 if (merge_label
== base_label
1143 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1145 base_high
= CASE_HIGH (merge_case
) ?
1146 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1147 CASE_HIGH (base_case
) = base_high
;
1148 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1157 /* Compress the case labels in the label vector, and adjust the
1158 length of the vector. */
1159 for (i
= 0, j
= 0; i
< new_size
; i
++)
1161 while (! TREE_VEC_ELT (labels
, j
))
1163 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1165 TREE_VEC_LENGTH (labels
) = new_size
;
1170 /* Checks whether we can merge block B into block A. */
1173 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1176 block_stmt_iterator bsi
;
1179 if (!single_succ_p (a
))
1182 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1185 if (single_succ (a
) != b
)
1188 if (!single_pred_p (b
))
1191 if (b
== EXIT_BLOCK_PTR
)
1194 /* If A ends by a statement causing exceptions or something similar, we
1195 cannot merge the blocks. */
1196 stmt
= last_stmt (a
);
1197 if (stmt
&& stmt_ends_bb_p (stmt
))
1200 /* Do not allow a block with only a non-local label to be merged. */
1201 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1202 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1205 /* It must be possible to eliminate all phi nodes in B. If ssa form
1206 is not up-to-date, we cannot eliminate any phis; however, if only
1207 some symbols as whole are marked for renaming, this is not a problem,
1208 as phi nodes for those symbols are irrelevant in updating anyway. */
1209 phi
= phi_nodes (b
);
1212 if (name_mappings_registered_p ())
1215 for (; phi
; phi
= PHI_CHAIN (phi
))
1216 if (!is_gimple_reg (PHI_RESULT (phi
))
1217 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1221 /* Do not remove user labels. */
1222 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1224 stmt
= bsi_stmt (bsi
);
1225 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1227 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1231 /* Protect the loop latches. */
1233 && b
->loop_father
->latch
== b
)
1239 /* Replaces all uses of NAME by VAL. */
1242 replace_uses_by (tree name
, tree val
)
1244 imm_use_iterator imm_iter
;
1250 FOR_EACH_IMM_USE_STMT (stmt
, imm_iter
, name
)
1252 FOR_EACH_IMM_USE_ON_STMT (use
, imm_iter
)
1254 replace_exp (use
, val
);
1256 if (TREE_CODE (stmt
) == PHI_NODE
)
1258 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1259 if (e
->flags
& EDGE_ABNORMAL
)
1261 /* This can only occur for virtual operands, since
1262 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1263 would prevent replacement. */
1264 gcc_assert (!is_gimple_reg (name
));
1265 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1269 if (TREE_CODE (stmt
) != PHI_NODE
)
1273 fold_stmt_inplace (stmt
);
1274 rhs
= get_rhs (stmt
);
1275 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1276 recompute_tree_invariant_for_addr_expr (rhs
);
1278 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1279 mark_new_vars_to_rename (stmt
);
1283 gcc_assert (num_imm_uses (name
) == 0);
1285 /* Also update the trees stored in loop structures. */
1290 for (i
= 0; i
< current_loops
->num
; i
++)
1292 loop
= current_loops
->parray
[i
];
1294 substitute_in_loop_info (loop
, name
, val
);
1299 /* Merge block B into block A. */
1302 tree_merge_blocks (basic_block a
, basic_block b
)
1304 block_stmt_iterator bsi
;
1305 tree_stmt_iterator last
;
1309 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1311 /* Remove all single-valued PHI nodes from block B of the form
1312 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1314 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1316 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1318 bool may_replace_uses
= may_propagate_copy (def
, use
);
1320 /* In case we have loops to care about, do not propagate arguments of
1321 loop closed ssa phi nodes. */
1323 && is_gimple_reg (def
)
1324 && TREE_CODE (use
) == SSA_NAME
1325 && a
->loop_father
!= b
->loop_father
)
1326 may_replace_uses
= false;
1328 if (!may_replace_uses
)
1330 gcc_assert (is_gimple_reg (def
));
1332 /* Note that just emitting the copies is fine -- there is no problem
1333 with ordering of phi nodes. This is because A is the single
1334 predecessor of B, therefore results of the phi nodes cannot
1335 appear as arguments of the phi nodes. */
1336 copy
= build2_gimple (GIMPLE_MODIFY_STMT
, def
, use
);
1337 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1338 SET_PHI_RESULT (phi
, NULL_TREE
);
1339 SSA_NAME_DEF_STMT (def
) = copy
;
1342 replace_uses_by (def
, use
);
1344 remove_phi_node (phi
, NULL
);
1347 /* Ensure that B follows A. */
1348 move_block_after (b
, a
);
1350 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1351 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1353 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1354 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1356 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1358 tree label
= bsi_stmt (bsi
);
1360 bsi_remove (&bsi
, false);
1361 /* Now that we can thread computed gotos, we might have
1362 a situation where we have a forced label in block B
1363 However, the label at the start of block B might still be
1364 used in other ways (think about the runtime checking for
1365 Fortran assigned gotos). So we can not just delete the
1366 label. Instead we move the label to the start of block A. */
1367 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1369 block_stmt_iterator dest_bsi
= bsi_start (a
);
1370 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1375 change_bb_for_stmt (bsi_stmt (bsi
), a
);
1380 /* Merge the chains. */
1381 last
= tsi_last (a
->stmt_list
);
1382 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1383 b
->stmt_list
= NULL
;
1387 /* Return the one of two successors of BB that is not reachable by a
1388 reached by a complex edge, if there is one. Else, return BB. We use
1389 this in optimizations that use post-dominators for their heuristics,
1390 to catch the cases in C++ where function calls are involved. */
1393 single_noncomplex_succ (basic_block bb
)
1396 if (EDGE_COUNT (bb
->succs
) != 2)
1399 e0
= EDGE_SUCC (bb
, 0);
1400 e1
= EDGE_SUCC (bb
, 1);
1401 if (e0
->flags
& EDGE_COMPLEX
)
1403 if (e1
->flags
& EDGE_COMPLEX
)
1410 /* Walk the function tree removing unnecessary statements.
1412 * Empty statement nodes are removed
1414 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1416 * Unnecessary COND_EXPRs are removed
1418 * Some unnecessary BIND_EXPRs are removed
1420 Clearly more work could be done. The trick is doing the analysis
1421 and removal fast enough to be a net improvement in compile times.
1423 Note that when we remove a control structure such as a COND_EXPR
1424 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1425 to ensure we eliminate all the useless code. */
1436 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1439 remove_useless_stmts_warn_notreached (tree stmt
)
1441 if (EXPR_HAS_LOCATION (stmt
))
1443 location_t loc
= EXPR_LOCATION (stmt
);
1444 if (LOCATION_LINE (loc
) > 0)
1446 warning (0, "%Hwill never be executed", &loc
);
1451 switch (TREE_CODE (stmt
))
1453 case STATEMENT_LIST
:
1455 tree_stmt_iterator i
;
1456 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1457 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1463 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1465 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1467 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1471 case TRY_FINALLY_EXPR
:
1472 case TRY_CATCH_EXPR
:
1473 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1475 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1480 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1481 case EH_FILTER_EXPR
:
1482 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1484 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1487 /* Not a live container. */
1495 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1497 tree then_clause
, else_clause
, cond
;
1498 bool save_has_label
, then_has_label
, else_has_label
;
1500 save_has_label
= data
->has_label
;
1501 data
->has_label
= false;
1502 data
->last_goto
= NULL
;
1504 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1506 then_has_label
= data
->has_label
;
1507 data
->has_label
= false;
1508 data
->last_goto
= NULL
;
1510 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1512 else_has_label
= data
->has_label
;
1513 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1515 then_clause
= COND_EXPR_THEN (*stmt_p
);
1516 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1517 cond
= fold (COND_EXPR_COND (*stmt_p
));
1519 /* If neither arm does anything at all, we can remove the whole IF. */
1520 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1522 *stmt_p
= build_empty_stmt ();
1523 data
->repeat
= true;
1526 /* If there are no reachable statements in an arm, then we can
1527 zap the entire conditional. */
1528 else if (integer_nonzerop (cond
) && !else_has_label
)
1530 if (warn_notreached
)
1531 remove_useless_stmts_warn_notreached (else_clause
);
1532 *stmt_p
= then_clause
;
1533 data
->repeat
= true;
1535 else if (integer_zerop (cond
) && !then_has_label
)
1537 if (warn_notreached
)
1538 remove_useless_stmts_warn_notreached (then_clause
);
1539 *stmt_p
= else_clause
;
1540 data
->repeat
= true;
1543 /* Check a couple of simple things on then/else with single stmts. */
1546 tree then_stmt
= expr_only (then_clause
);
1547 tree else_stmt
= expr_only (else_clause
);
1549 /* Notice branches to a common destination. */
1550 if (then_stmt
&& else_stmt
1551 && TREE_CODE (then_stmt
) == GOTO_EXPR
1552 && TREE_CODE (else_stmt
) == GOTO_EXPR
1553 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1555 *stmt_p
= then_stmt
;
1556 data
->repeat
= true;
1559 /* If the THEN/ELSE clause merely assigns a value to a variable or
1560 parameter which is already known to contain that value, then
1561 remove the useless THEN/ELSE clause. */
1562 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1565 && TREE_CODE (else_stmt
) == GIMPLE_MODIFY_STMT
1566 && GIMPLE_STMT_OPERAND (else_stmt
, 0) == cond
1567 && integer_zerop (GIMPLE_STMT_OPERAND (else_stmt
, 1)))
1568 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1570 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1571 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1572 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1573 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1575 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1576 ? then_stmt
: else_stmt
);
1577 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1578 ? &COND_EXPR_THEN (*stmt_p
)
1579 : &COND_EXPR_ELSE (*stmt_p
));
1582 && TREE_CODE (stmt
) == GIMPLE_MODIFY_STMT
1583 && GIMPLE_STMT_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1584 && GIMPLE_STMT_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1585 *location
= alloc_stmt_list ();
1589 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1590 would be re-introduced during lowering. */
1591 data
->last_goto
= NULL
;
1596 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1598 bool save_may_branch
, save_may_throw
;
1599 bool this_may_branch
, this_may_throw
;
1601 /* Collect may_branch and may_throw information for the body only. */
1602 save_may_branch
= data
->may_branch
;
1603 save_may_throw
= data
->may_throw
;
1604 data
->may_branch
= false;
1605 data
->may_throw
= false;
1606 data
->last_goto
= NULL
;
1608 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1610 this_may_branch
= data
->may_branch
;
1611 this_may_throw
= data
->may_throw
;
1612 data
->may_branch
|= save_may_branch
;
1613 data
->may_throw
|= save_may_throw
;
1614 data
->last_goto
= NULL
;
1616 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1618 /* If the body is empty, then we can emit the FINALLY block without
1619 the enclosing TRY_FINALLY_EXPR. */
1620 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1622 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1623 data
->repeat
= true;
1626 /* If the handler is empty, then we can emit the TRY block without
1627 the enclosing TRY_FINALLY_EXPR. */
1628 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1630 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1631 data
->repeat
= true;
1634 /* If the body neither throws, nor branches, then we can safely
1635 string the TRY and FINALLY blocks together. */
1636 else if (!this_may_branch
&& !this_may_throw
)
1638 tree stmt
= *stmt_p
;
1639 *stmt_p
= TREE_OPERAND (stmt
, 0);
1640 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1641 data
->repeat
= true;
1647 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1649 bool save_may_throw
, this_may_throw
;
1650 tree_stmt_iterator i
;
1653 /* Collect may_throw information for the body only. */
1654 save_may_throw
= data
->may_throw
;
1655 data
->may_throw
= false;
1656 data
->last_goto
= NULL
;
1658 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1660 this_may_throw
= data
->may_throw
;
1661 data
->may_throw
= save_may_throw
;
1663 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1664 if (!this_may_throw
)
1666 if (warn_notreached
)
1667 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1668 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1669 data
->repeat
= true;
1673 /* Process the catch clause specially. We may be able to tell that
1674 no exceptions propagate past this point. */
1676 this_may_throw
= true;
1677 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1678 stmt
= tsi_stmt (i
);
1679 data
->last_goto
= NULL
;
1681 switch (TREE_CODE (stmt
))
1684 for (; !tsi_end_p (i
); tsi_next (&i
))
1686 stmt
= tsi_stmt (i
);
1687 /* If we catch all exceptions, then the body does not
1688 propagate exceptions past this point. */
1689 if (CATCH_TYPES (stmt
) == NULL
)
1690 this_may_throw
= false;
1691 data
->last_goto
= NULL
;
1692 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1696 case EH_FILTER_EXPR
:
1697 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1698 this_may_throw
= false;
1699 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1700 this_may_throw
= false;
1701 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1705 /* Otherwise this is a cleanup. */
1706 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1708 /* If the cleanup is empty, then we can emit the TRY block without
1709 the enclosing TRY_CATCH_EXPR. */
1710 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1712 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1713 data
->repeat
= true;
1717 data
->may_throw
|= this_may_throw
;
1722 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1726 /* First remove anything underneath the BIND_EXPR. */
1727 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1729 /* If the BIND_EXPR has no variables, then we can pull everything
1730 up one level and remove the BIND_EXPR, unless this is the toplevel
1731 BIND_EXPR for the current function or an inlined function.
1733 When this situation occurs we will want to apply this
1734 optimization again. */
1735 block
= BIND_EXPR_BLOCK (*stmt_p
);
1736 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1737 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1739 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1740 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1743 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1744 data
->repeat
= true;
1750 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1752 tree dest
= GOTO_DESTINATION (*stmt_p
);
1754 data
->may_branch
= true;
1755 data
->last_goto
= NULL
;
1757 /* Record the last goto expr, so that we can delete it if unnecessary. */
1758 if (TREE_CODE (dest
) == LABEL_DECL
)
1759 data
->last_goto
= stmt_p
;
1764 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1766 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1768 data
->has_label
= true;
1770 /* We do want to jump across non-local label receiver code. */
1771 if (DECL_NONLOCAL (label
))
1772 data
->last_goto
= NULL
;
1774 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1776 *data
->last_goto
= build_empty_stmt ();
1777 data
->repeat
= true;
1780 /* ??? Add something here to delete unused labels. */
1784 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1785 decl. This allows us to eliminate redundant or useless
1786 calls to "const" functions.
1788 Gimplifier already does the same operation, but we may notice functions
1789 being const and pure once their calls has been gimplified, so we need
1790 to update the flag. */
1793 update_call_expr_flags (tree call
)
1795 tree decl
= get_callee_fndecl (call
);
1798 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1799 TREE_SIDE_EFFECTS (call
) = 0;
1800 if (TREE_NOTHROW (decl
))
1801 TREE_NOTHROW (call
) = 1;
1805 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1808 notice_special_calls (tree t
)
1810 int flags
= call_expr_flags (t
);
1812 if (flags
& ECF_MAY_BE_ALLOCA
)
1813 current_function_calls_alloca
= true;
1814 if (flags
& ECF_RETURNS_TWICE
)
1815 current_function_calls_setjmp
= true;
1819 /* Clear flags set by notice_special_calls. Used by dead code removal
1820 to update the flags. */
1823 clear_special_calls (void)
1825 current_function_calls_alloca
= false;
1826 current_function_calls_setjmp
= false;
1831 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1835 switch (TREE_CODE (t
))
1838 remove_useless_stmts_cond (tp
, data
);
1841 case TRY_FINALLY_EXPR
:
1842 remove_useless_stmts_tf (tp
, data
);
1845 case TRY_CATCH_EXPR
:
1846 remove_useless_stmts_tc (tp
, data
);
1850 remove_useless_stmts_bind (tp
, data
);
1854 remove_useless_stmts_goto (tp
, data
);
1858 remove_useless_stmts_label (tp
, data
);
1863 data
->last_goto
= NULL
;
1864 data
->may_branch
= true;
1869 data
->last_goto
= NULL
;
1870 notice_special_calls (t
);
1871 update_call_expr_flags (t
);
1872 if (tree_could_throw_p (t
))
1873 data
->may_throw
= true;
1879 case GIMPLE_MODIFY_STMT
:
1880 data
->last_goto
= NULL
;
1882 op
= get_call_expr_in (t
);
1885 update_call_expr_flags (op
);
1886 notice_special_calls (op
);
1888 if (tree_could_throw_p (t
))
1889 data
->may_throw
= true;
1892 case STATEMENT_LIST
:
1894 tree_stmt_iterator i
= tsi_start (t
);
1895 while (!tsi_end_p (i
))
1898 if (IS_EMPTY_STMT (t
))
1904 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1907 if (TREE_CODE (t
) == STATEMENT_LIST
)
1909 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1919 data
->last_goto
= NULL
;
1923 data
->last_goto
= NULL
;
1929 remove_useless_stmts (void)
1931 struct rus_data data
;
1933 clear_special_calls ();
1937 memset (&data
, 0, sizeof (data
));
1938 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1940 while (data
.repeat
);
1945 struct tree_opt_pass pass_remove_useless_stmts
=
1947 "useless", /* name */
1949 remove_useless_stmts
, /* execute */
1952 0, /* static_pass_number */
1954 PROP_gimple_any
, /* properties_required */
1955 0, /* properties_provided */
1956 0, /* properties_destroyed */
1957 0, /* todo_flags_start */
1958 TODO_dump_func
, /* todo_flags_finish */
1962 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1965 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1969 /* Since this block is no longer reachable, we can just delete all
1970 of its PHI nodes. */
1971 phi
= phi_nodes (bb
);
1974 tree next
= PHI_CHAIN (phi
);
1975 remove_phi_node (phi
, NULL_TREE
);
1979 /* Remove edges to BB's successors. */
1980 while (EDGE_COUNT (bb
->succs
) > 0)
1981 remove_edge (EDGE_SUCC (bb
, 0));
1985 /* Remove statements of basic block BB. */
1988 remove_bb (basic_block bb
)
1990 block_stmt_iterator i
;
1991 #ifdef USE_MAPPED_LOCATION
1992 source_location loc
= UNKNOWN_LOCATION
;
1994 source_locus loc
= 0;
1999 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2000 if (dump_flags
& TDF_DETAILS
)
2002 dump_bb (bb
, dump_file
, 0);
2003 fprintf (dump_file
, "\n");
2009 struct loop
*loop
= bb
->loop_father
;
2011 /* If a loop gets removed, clean up the information associated
2013 if (loop
->latch
== bb
2014 || loop
->header
== bb
)
2015 free_numbers_of_iterations_estimates_loop (loop
);
2018 /* Remove all the instructions in the block. */
2019 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2021 tree stmt
= bsi_stmt (i
);
2022 if (TREE_CODE (stmt
) == LABEL_EXPR
2023 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2024 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2027 block_stmt_iterator new_bsi
;
2029 /* A non-reachable non-local label may still be referenced.
2030 But it no longer needs to carry the extra semantics of
2032 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2034 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2035 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2038 new_bb
= bb
->prev_bb
;
2039 new_bsi
= bsi_start (new_bb
);
2040 bsi_remove (&i
, false);
2041 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2045 /* Release SSA definitions if we are in SSA. Note that we
2046 may be called when not in SSA. For example,
2047 final_cleanup calls this function via
2048 cleanup_tree_cfg. */
2049 if (gimple_in_ssa_p (cfun
))
2050 release_defs (stmt
);
2052 bsi_remove (&i
, true);
2055 /* Don't warn for removed gotos. Gotos are often removed due to
2056 jump threading, thus resulting in bogus warnings. Not great,
2057 since this way we lose warnings for gotos in the original
2058 program that are indeed unreachable. */
2059 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2061 #ifdef USE_MAPPED_LOCATION
2062 if (EXPR_HAS_LOCATION (stmt
))
2063 loc
= EXPR_LOCATION (stmt
);
2066 t
= EXPR_LOCUS (stmt
);
2067 if (t
&& LOCATION_LINE (*t
) > 0)
2073 /* If requested, give a warning that the first statement in the
2074 block is unreachable. We walk statements backwards in the
2075 loop above, so the last statement we process is the first statement
2077 #ifdef USE_MAPPED_LOCATION
2078 if (loc
> BUILTINS_LOCATION
)
2079 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2082 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2085 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2089 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2090 predicate VAL, return the edge that will be taken out of the block.
2091 If VAL does not match a unique edge, NULL is returned. */
2094 find_taken_edge (basic_block bb
, tree val
)
2098 stmt
= last_stmt (bb
);
2101 gcc_assert (is_ctrl_stmt (stmt
));
2104 if (! is_gimple_min_invariant (val
))
2107 if (TREE_CODE (stmt
) == COND_EXPR
)
2108 return find_taken_edge_cond_expr (bb
, val
);
2110 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2111 return find_taken_edge_switch_expr (bb
, val
);
2113 if (computed_goto_p (stmt
))
2114 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2119 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2120 statement, determine which of the outgoing edges will be taken out of the
2121 block. Return NULL if either edge may be taken. */
2124 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2129 dest
= label_to_block (val
);
2132 e
= find_edge (bb
, dest
);
2133 gcc_assert (e
!= NULL
);
2139 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2140 statement, determine which of the two edges will be taken out of the
2141 block. Return NULL if either edge may be taken. */
2144 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2146 edge true_edge
, false_edge
;
2148 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2150 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2151 return (zero_p (val
) ? false_edge
: true_edge
);
2154 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2155 statement, determine which edge will be taken out of the block. Return
2156 NULL if any edge may be taken. */
2159 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2161 tree switch_expr
, taken_case
;
2162 basic_block dest_bb
;
2165 switch_expr
= last_stmt (bb
);
2166 taken_case
= find_case_label_for_value (switch_expr
, val
);
2167 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2169 e
= find_edge (bb
, dest_bb
);
2175 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2176 We can make optimal use here of the fact that the case labels are
2177 sorted: We can do a binary search for a case matching VAL. */
2180 find_case_label_for_value (tree switch_expr
, tree val
)
2182 tree vec
= SWITCH_LABELS (switch_expr
);
2183 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2184 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2186 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2188 size_t i
= (high
+ low
) / 2;
2189 tree t
= TREE_VEC_ELT (vec
, i
);
2192 /* Cache the result of comparing CASE_LOW and val. */
2193 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2200 if (CASE_HIGH (t
) == NULL
)
2202 /* A singe-valued case label. */
2208 /* A case range. We can only handle integer ranges. */
2209 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2214 return default_case
;
2220 /*---------------------------------------------------------------------------
2222 ---------------------------------------------------------------------------*/
2224 /* Dump tree-specific information of block BB to file OUTF. */
2227 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2229 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2233 /* Dump a basic block on stderr. */
2236 debug_tree_bb (basic_block bb
)
2238 dump_bb (bb
, stderr
, 0);
2242 /* Dump basic block with index N on stderr. */
2245 debug_tree_bb_n (int n
)
2247 debug_tree_bb (BASIC_BLOCK (n
));
2248 return BASIC_BLOCK (n
);
2252 /* Dump the CFG on stderr.
2254 FLAGS are the same used by the tree dumping functions
2255 (see TDF_* in tree-pass.h). */
2258 debug_tree_cfg (int flags
)
2260 dump_tree_cfg (stderr
, flags
);
2264 /* Dump the program showing basic block boundaries on the given FILE.
2266 FLAGS are the same used by the tree dumping functions (see TDF_* in
2270 dump_tree_cfg (FILE *file
, int flags
)
2272 if (flags
& TDF_DETAILS
)
2274 const char *funcname
2275 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2278 fprintf (file
, ";; Function %s\n\n", funcname
);
2279 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2280 n_basic_blocks
, n_edges
, last_basic_block
);
2282 brief_dump_cfg (file
);
2283 fprintf (file
, "\n");
2286 if (flags
& TDF_STATS
)
2287 dump_cfg_stats (file
);
2289 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2293 /* Dump CFG statistics on FILE. */
2296 dump_cfg_stats (FILE *file
)
2298 static long max_num_merged_labels
= 0;
2299 unsigned long size
, total
= 0;
2302 const char * const fmt_str
= "%-30s%-13s%12s\n";
2303 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2304 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2305 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2306 const char *funcname
2307 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2310 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2312 fprintf (file
, "---------------------------------------------------------\n");
2313 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2314 fprintf (file
, fmt_str
, "", " instances ", "used ");
2315 fprintf (file
, "---------------------------------------------------------\n");
2317 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2319 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2320 SCALE (size
), LABEL (size
));
2324 num_edges
+= EDGE_COUNT (bb
->succs
);
2325 size
= num_edges
* sizeof (struct edge_def
);
2327 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2329 fprintf (file
, "---------------------------------------------------------\n");
2330 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2332 fprintf (file
, "---------------------------------------------------------\n");
2333 fprintf (file
, "\n");
2335 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2336 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2338 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2339 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2341 fprintf (file
, "\n");
2345 /* Dump CFG statistics on stderr. Keep extern so that it's always
2346 linked in the final executable. */
2349 debug_cfg_stats (void)
2351 dump_cfg_stats (stderr
);
2355 /* Dump the flowgraph to a .vcg FILE. */
2358 tree_cfg2vcg (FILE *file
)
2363 const char *funcname
2364 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2366 /* Write the file header. */
2367 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2368 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2369 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2371 /* Write blocks and edges. */
2372 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2374 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2377 if (e
->flags
& EDGE_FAKE
)
2378 fprintf (file
, " linestyle: dotted priority: 10");
2380 fprintf (file
, " linestyle: solid priority: 100");
2382 fprintf (file
, " }\n");
2388 enum tree_code head_code
, end_code
;
2389 const char *head_name
, *end_name
;
2392 tree first
= first_stmt (bb
);
2393 tree last
= last_stmt (bb
);
2397 head_code
= TREE_CODE (first
);
2398 head_name
= tree_code_name
[head_code
];
2399 head_line
= get_lineno (first
);
2402 head_name
= "no-statement";
2406 end_code
= TREE_CODE (last
);
2407 end_name
= tree_code_name
[end_code
];
2408 end_line
= get_lineno (last
);
2411 end_name
= "no-statement";
2413 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2414 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2417 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2419 if (e
->dest
== EXIT_BLOCK_PTR
)
2420 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2422 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2424 if (e
->flags
& EDGE_FAKE
)
2425 fprintf (file
, " priority: 10 linestyle: dotted");
2427 fprintf (file
, " priority: 100 linestyle: solid");
2429 fprintf (file
, " }\n");
2432 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2436 fputs ("}\n\n", file
);
2441 /*---------------------------------------------------------------------------
2442 Miscellaneous helpers
2443 ---------------------------------------------------------------------------*/
2445 /* Return true if T represents a stmt that always transfers control. */
2448 is_ctrl_stmt (tree t
)
2450 return (TREE_CODE (t
) == COND_EXPR
2451 || TREE_CODE (t
) == SWITCH_EXPR
2452 || TREE_CODE (t
) == GOTO_EXPR
2453 || TREE_CODE (t
) == RETURN_EXPR
2454 || TREE_CODE (t
) == RESX_EXPR
);
2458 /* Return true if T is a statement that may alter the flow of control
2459 (e.g., a call to a non-returning function). */
2462 is_ctrl_altering_stmt (tree t
)
2467 call
= get_call_expr_in (t
);
2470 /* A non-pure/const CALL_EXPR alters flow control if the current
2471 function has nonlocal labels. */
2472 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2475 /* A CALL_EXPR also alters control flow if it does not return. */
2476 if (call_expr_flags (call
) & ECF_NORETURN
)
2480 /* OpenMP directives alter control flow. */
2481 if (OMP_DIRECTIVE_P (t
))
2484 /* If a statement can throw, it alters control flow. */
2485 return tree_can_throw_internal (t
);
2489 /* Return true if T is a computed goto. */
2492 computed_goto_p (tree t
)
2494 return (TREE_CODE (t
) == GOTO_EXPR
2495 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2499 /* Return true if T is a simple local goto. */
2502 simple_goto_p (tree t
)
2504 return (TREE_CODE (t
) == GOTO_EXPR
2505 && TREE_CODE (GOTO_DESTINATION (t
)) == LABEL_DECL
);
2509 /* Return true if T can make an abnormal transfer of control flow.
2510 Transfers of control flow associated with EH are excluded. */
2513 tree_can_make_abnormal_goto (tree t
)
2515 if (computed_goto_p (t
))
2517 if (TREE_CODE (t
) == GIMPLE_MODIFY_STMT
)
2518 t
= GIMPLE_STMT_OPERAND (t
, 1);
2519 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2520 t
= TREE_OPERAND (t
, 0);
2521 if (TREE_CODE (t
) == CALL_EXPR
)
2522 return TREE_SIDE_EFFECTS (t
) && current_function_has_nonlocal_label
;
2527 /* Return true if T should start a new basic block. PREV_T is the
2528 statement preceding T. It is used when T is a label or a case label.
2529 Labels should only start a new basic block if their previous statement
2530 wasn't a label. Otherwise, sequence of labels would generate
2531 unnecessary basic blocks that only contain a single label. */
2534 stmt_starts_bb_p (tree t
, tree prev_t
)
2539 /* LABEL_EXPRs start a new basic block only if the preceding
2540 statement wasn't a label of the same type. This prevents the
2541 creation of consecutive blocks that have nothing but a single
2543 if (TREE_CODE (t
) == LABEL_EXPR
)
2545 /* Nonlocal and computed GOTO targets always start a new block. */
2546 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2547 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2550 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2552 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2555 cfg_stats
.num_merged_labels
++;
2566 /* Return true if T should end a basic block. */
2569 stmt_ends_bb_p (tree t
)
2571 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2575 /* Add gotos that used to be represented implicitly in the CFG. */
2578 disband_implicit_edges (void)
2581 block_stmt_iterator last
;
2588 last
= bsi_last (bb
);
2589 stmt
= last_stmt (bb
);
2591 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2593 /* Remove superfluous gotos from COND_EXPR branches. Moved
2594 from cfg_remove_useless_stmts here since it violates the
2595 invariants for tree--cfg correspondence and thus fits better
2596 here where we do it anyway. */
2597 e
= find_edge (bb
, bb
->next_bb
);
2600 if (e
->flags
& EDGE_TRUE_VALUE
)
2601 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2602 else if (e
->flags
& EDGE_FALSE_VALUE
)
2603 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2606 e
->flags
|= EDGE_FALLTHRU
;
2612 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2614 /* Remove the RETURN_EXPR if we may fall though to the exit
2616 gcc_assert (single_succ_p (bb
));
2617 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2619 if (bb
->next_bb
== EXIT_BLOCK_PTR
2620 && !TREE_OPERAND (stmt
, 0))
2622 bsi_remove (&last
, true);
2623 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2628 /* There can be no fallthru edge if the last statement is a control
2630 if (stmt
&& is_ctrl_stmt (stmt
))
2633 /* Find a fallthru edge and emit the goto if necessary. */
2634 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2635 if (e
->flags
& EDGE_FALLTHRU
)
2638 if (!e
|| e
->dest
== bb
->next_bb
)
2641 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2642 label
= tree_block_label (e
->dest
);
2644 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2645 #ifdef USE_MAPPED_LOCATION
2646 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2648 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2650 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2651 e
->flags
&= ~EDGE_FALLTHRU
;
2655 /* Remove block annotations and other datastructures. */
2658 delete_tree_cfg_annotations (void)
2660 label_to_block_map
= NULL
;
2664 /* Return the first statement in basic block BB. */
2667 first_stmt (basic_block bb
)
2669 block_stmt_iterator i
= bsi_start (bb
);
2670 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2674 /* Return the last statement in basic block BB. */
2677 last_stmt (basic_block bb
)
2679 block_stmt_iterator b
= bsi_last (bb
);
2680 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2684 /* Return a pointer to the last statement in block BB. */
2687 last_stmt_ptr (basic_block bb
)
2689 block_stmt_iterator last
= bsi_last (bb
);
2690 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2694 /* Return the last statement of an otherwise empty block. Return NULL
2695 if the block is totally empty, or if it contains more than one
2699 last_and_only_stmt (basic_block bb
)
2701 block_stmt_iterator i
= bsi_last (bb
);
2707 last
= bsi_stmt (i
);
2712 /* Empty statements should no longer appear in the instruction stream.
2713 Everything that might have appeared before should be deleted by
2714 remove_useless_stmts, and the optimizers should just bsi_remove
2715 instead of smashing with build_empty_stmt.
2717 Thus the only thing that should appear here in a block containing
2718 one executable statement is a label. */
2719 prev
= bsi_stmt (i
);
2720 if (TREE_CODE (prev
) == LABEL_EXPR
)
2727 /* Mark BB as the basic block holding statement T. */
2730 set_bb_for_stmt (tree t
, basic_block bb
)
2732 if (TREE_CODE (t
) == PHI_NODE
)
2734 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2736 tree_stmt_iterator i
;
2737 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2738 set_bb_for_stmt (tsi_stmt (i
), bb
);
2742 stmt_ann_t ann
= get_stmt_ann (t
);
2745 /* If the statement is a label, add the label to block-to-labels map
2746 so that we can speed up edge creation for GOTO_EXPRs. */
2747 if (TREE_CODE (t
) == LABEL_EXPR
)
2751 t
= LABEL_EXPR_LABEL (t
);
2752 uid
= LABEL_DECL_UID (t
);
2755 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2756 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2757 if (old_len
<= (unsigned) uid
)
2760 unsigned new_len
= 3 * uid
/ 2;
2762 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2764 addr
= VEC_address (basic_block
, label_to_block_map
);
2765 memset (&addr
[old_len
],
2766 0, sizeof (basic_block
) * (new_len
- old_len
));
2770 /* We're moving an existing label. Make sure that we've
2771 removed it from the old block. */
2773 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2774 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2779 /* Faster version of set_bb_for_stmt that assume that statement is being moved
2780 from one basic block to another.
2781 For BB splitting we can run into quadratic case, so performance is quite
2782 important and knowing that the tables are big enough, change_bb_for_stmt
2783 can inline as leaf function. */
2785 change_bb_for_stmt (tree t
, basic_block bb
)
2787 get_stmt_ann (t
)->bb
= bb
;
2788 if (TREE_CODE (t
) == LABEL_EXPR
)
2789 VEC_replace (basic_block
, label_to_block_map
,
2790 LABEL_DECL_UID (LABEL_EXPR_LABEL (t
)), bb
);
2793 /* Finds iterator for STMT. */
2795 extern block_stmt_iterator
2796 bsi_for_stmt (tree stmt
)
2798 block_stmt_iterator bsi
;
2800 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2801 if (bsi_stmt (bsi
) == stmt
)
2807 /* Mark statement T as modified, and update it. */
2809 update_modified_stmts (tree t
)
2811 if (TREE_CODE (t
) == STATEMENT_LIST
)
2813 tree_stmt_iterator i
;
2815 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2817 stmt
= tsi_stmt (i
);
2818 update_stmt_if_modified (stmt
);
2822 update_stmt_if_modified (t
);
2825 /* Insert statement (or statement list) T before the statement
2826 pointed-to by iterator I. M specifies how to update iterator I
2827 after insertion (see enum bsi_iterator_update). */
2830 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2832 set_bb_for_stmt (t
, i
->bb
);
2833 update_modified_stmts (t
);
2834 tsi_link_before (&i
->tsi
, t
, m
);
2838 /* Insert statement (or statement list) T after the statement
2839 pointed-to by iterator I. M specifies how to update iterator I
2840 after insertion (see enum bsi_iterator_update). */
2843 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2845 set_bb_for_stmt (t
, i
->bb
);
2846 update_modified_stmts (t
);
2847 tsi_link_after (&i
->tsi
, t
, m
);
2851 /* Remove the statement pointed to by iterator I. The iterator is updated
2852 to the next statement.
2854 When REMOVE_EH_INFO is true we remove the statement pointed to by
2855 iterator I from the EH tables. Otherwise we do not modify the EH
2858 Generally, REMOVE_EH_INFO should be true when the statement is going to
2859 be removed from the IL and not reinserted elsewhere. */
2862 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2864 tree t
= bsi_stmt (*i
);
2865 set_bb_for_stmt (t
, NULL
);
2866 delink_stmt_imm_use (t
);
2867 tsi_delink (&i
->tsi
);
2868 mark_stmt_modified (t
);
2870 remove_stmt_from_eh_region (t
);
2874 /* Move the statement at FROM so it comes right after the statement at TO. */
2877 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2879 tree stmt
= bsi_stmt (*from
);
2880 bsi_remove (from
, false);
2881 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2885 /* Move the statement at FROM so it comes right before the statement at TO. */
2888 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2890 tree stmt
= bsi_stmt (*from
);
2891 bsi_remove (from
, false);
2892 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2896 /* Move the statement at FROM to the end of basic block BB. */
2899 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2901 block_stmt_iterator last
= bsi_last (bb
);
2903 /* Have to check bsi_end_p because it could be an empty block. */
2904 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2905 bsi_move_before (from
, &last
);
2907 bsi_move_after (from
, &last
);
2911 /* Replace the contents of the statement pointed to by iterator BSI
2912 with STMT. If UPDATE_EH_INFO is true, the exception handling
2913 information of the original statement is moved to the new statement. */
2916 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2919 tree orig_stmt
= bsi_stmt (*bsi
);
2921 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2922 set_bb_for_stmt (stmt
, bsi
->bb
);
2924 /* Preserve EH region information from the original statement, if
2925 requested by the caller. */
2928 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2931 remove_stmt_from_eh_region (orig_stmt
);
2932 add_stmt_to_eh_region (stmt
, eh_region
);
2936 delink_stmt_imm_use (orig_stmt
);
2937 *bsi_stmt_ptr (*bsi
) = stmt
;
2938 mark_stmt_modified (stmt
);
2939 update_modified_stmts (stmt
);
2943 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2944 is made to place the statement in an existing basic block, but
2945 sometimes that isn't possible. When it isn't possible, the edge is
2946 split and the statement is added to the new block.
2948 In all cases, the returned *BSI points to the correct location. The
2949 return value is true if insertion should be done after the location,
2950 or false if it should be done before the location. If new basic block
2951 has to be created, it is stored in *NEW_BB. */
2954 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2955 basic_block
*new_bb
)
2957 basic_block dest
, src
;
2963 /* If the destination has one predecessor which has no PHI nodes,
2964 insert there. Except for the exit block.
2966 The requirement for no PHI nodes could be relaxed. Basically we
2967 would have to examine the PHIs to prove that none of them used
2968 the value set by the statement we want to insert on E. That
2969 hardly seems worth the effort. */
2970 if (single_pred_p (dest
)
2971 && ! phi_nodes (dest
)
2972 && dest
!= EXIT_BLOCK_PTR
)
2974 *bsi
= bsi_start (dest
);
2975 if (bsi_end_p (*bsi
))
2978 /* Make sure we insert after any leading labels. */
2979 tmp
= bsi_stmt (*bsi
);
2980 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2983 if (bsi_end_p (*bsi
))
2985 tmp
= bsi_stmt (*bsi
);
2988 if (bsi_end_p (*bsi
))
2990 *bsi
= bsi_last (dest
);
2997 /* If the source has one successor, the edge is not abnormal and
2998 the last statement does not end a basic block, insert there.
2999 Except for the entry block. */
3001 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3002 && single_succ_p (src
)
3003 && src
!= ENTRY_BLOCK_PTR
)
3005 *bsi
= bsi_last (src
);
3006 if (bsi_end_p (*bsi
))
3009 tmp
= bsi_stmt (*bsi
);
3010 if (!stmt_ends_bb_p (tmp
))
3013 /* Insert code just before returning the value. We may need to decompose
3014 the return in the case it contains non-trivial operand. */
3015 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3017 tree op
= TREE_OPERAND (tmp
, 0);
3018 if (op
&& !is_gimple_val (op
))
3020 gcc_assert (TREE_CODE (op
) == GIMPLE_MODIFY_STMT
);
3021 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3022 TREE_OPERAND (tmp
, 0) = GIMPLE_STMT_OPERAND (op
, 0);
3029 /* Otherwise, create a new basic block, and split this edge. */
3030 dest
= split_edge (e
);
3033 e
= single_pred_edge (dest
);
3038 /* This routine will commit all pending edge insertions, creating any new
3039 basic blocks which are necessary. */
3042 bsi_commit_edge_inserts (void)
3048 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3051 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3052 bsi_commit_one_edge_insert (e
, NULL
);
3056 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3057 to this block, otherwise set it to NULL. */
3060 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3064 if (PENDING_STMT (e
))
3066 block_stmt_iterator bsi
;
3067 tree stmt
= PENDING_STMT (e
);
3069 PENDING_STMT (e
) = NULL_TREE
;
3071 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3072 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3074 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3079 /* Add STMT to the pending list of edge E. No actual insertion is
3080 made until a call to bsi_commit_edge_inserts () is made. */
3083 bsi_insert_on_edge (edge e
, tree stmt
)
3085 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3088 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3089 block has to be created, it is returned. */
3092 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3094 block_stmt_iterator bsi
;
3095 basic_block new_bb
= NULL
;
3097 gcc_assert (!PENDING_STMT (e
));
3099 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3100 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3102 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3107 /*---------------------------------------------------------------------------
3108 Tree specific functions for CFG manipulation
3109 ---------------------------------------------------------------------------*/
3111 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3114 reinstall_phi_args (edge new_edge
, edge old_edge
)
3118 if (!PENDING_STMT (old_edge
))
3121 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3123 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3125 tree result
= TREE_PURPOSE (var
);
3126 tree arg
= TREE_VALUE (var
);
3128 gcc_assert (result
== PHI_RESULT (phi
));
3130 add_phi_arg (phi
, arg
, new_edge
);
3133 PENDING_STMT (old_edge
) = NULL
;
3136 /* Returns the basic block after which the new basic block created
3137 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3138 near its "logical" location. This is of most help to humans looking
3139 at debugging dumps. */
3142 split_edge_bb_loc (edge edge_in
)
3144 basic_block dest
= edge_in
->dest
;
3146 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3147 return edge_in
->src
;
3149 return dest
->prev_bb
;
3152 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3153 Abort on abnormal edges. */
3156 tree_split_edge (edge edge_in
)
3158 basic_block new_bb
, after_bb
, dest
;
3161 /* Abnormal edges cannot be split. */
3162 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3164 dest
= edge_in
->dest
;
3166 after_bb
= split_edge_bb_loc (edge_in
);
3168 new_bb
= create_empty_bb (after_bb
);
3169 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3170 new_bb
->count
= edge_in
->count
;
3171 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3172 new_edge
->probability
= REG_BR_PROB_BASE
;
3173 new_edge
->count
= edge_in
->count
;
3175 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3177 reinstall_phi_args (new_edge
, e
);
3183 /* Return true when BB has label LABEL in it. */
3186 has_label_p (basic_block bb
, tree label
)
3188 block_stmt_iterator bsi
;
3190 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3192 tree stmt
= bsi_stmt (bsi
);
3194 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3196 if (LABEL_EXPR_LABEL (stmt
) == label
)
3203 /* Callback for walk_tree, check that all elements with address taken are
3204 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3205 inside a PHI node. */
3208 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3211 bool in_phi
= (data
!= NULL
);
3216 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3217 #define CHECK_OP(N, MSG) \
3218 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3219 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3221 switch (TREE_CODE (t
))
3224 if (SSA_NAME_IN_FREE_LIST (t
))
3226 error ("SSA name in freelist but still referenced");
3232 x
= fold (ASSERT_EXPR_COND (t
));
3233 if (x
== boolean_false_node
)
3235 error ("ASSERT_EXPR with an always-false condition");
3243 case GIMPLE_MODIFY_STMT
:
3244 x
= GIMPLE_STMT_OPERAND (t
, 0);
3245 if (TREE_CODE (x
) == BIT_FIELD_REF
3246 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3248 error ("GIMPLE register modified with BIT_FIELD_REF");
3257 bool old_side_effects
;
3260 bool new_side_effects
;
3262 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3263 dead PHIs that take the address of something. But if the PHI
3264 result is dead, the fact that it takes the address of anything
3265 is irrelevant. Because we can not tell from here if a PHI result
3266 is dead, we just skip this check for PHIs altogether. This means
3267 we may be missing "valid" checks, but what can you do?
3268 This was PR19217. */
3272 old_invariant
= TREE_INVARIANT (t
);
3273 old_constant
= TREE_CONSTANT (t
);
3274 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3276 recompute_tree_invariant_for_addr_expr (t
);
3277 new_invariant
= TREE_INVARIANT (t
);
3278 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3279 new_constant
= TREE_CONSTANT (t
);
3281 if (old_invariant
!= new_invariant
)
3283 error ("invariant not recomputed when ADDR_EXPR changed");
3287 if (old_constant
!= new_constant
)
3289 error ("constant not recomputed when ADDR_EXPR changed");
3292 if (old_side_effects
!= new_side_effects
)
3294 error ("side effects not recomputed when ADDR_EXPR changed");
3298 /* Skip any references (they will be checked when we recurse down the
3299 tree) and ensure that any variable used as a prefix is marked
3301 for (x
= TREE_OPERAND (t
, 0);
3302 handled_component_p (x
);
3303 x
= TREE_OPERAND (x
, 0))
3306 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3308 if (!TREE_ADDRESSABLE (x
))
3310 error ("address taken, but ADDRESSABLE bit not set");
3317 x
= COND_EXPR_COND (t
);
3318 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3320 error ("non-boolean used in condition");
3323 if (!is_gimple_condexpr (x
))
3325 error ("invalid conditional operand");
3332 case FIX_TRUNC_EXPR
:
3337 case NON_LVALUE_EXPR
:
3338 case TRUTH_NOT_EXPR
:
3339 CHECK_OP (0, "invalid operand to unary operator");
3346 case ARRAY_RANGE_REF
:
3348 case VIEW_CONVERT_EXPR
:
3349 /* We have a nest of references. Verify that each of the operands
3350 that determine where to reference is either a constant or a variable,
3351 verify that the base is valid, and then show we've already checked
3353 while (handled_component_p (t
))
3355 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3356 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3357 else if (TREE_CODE (t
) == ARRAY_REF
3358 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3360 CHECK_OP (1, "invalid array index");
3361 if (TREE_OPERAND (t
, 2))
3362 CHECK_OP (2, "invalid array lower bound");
3363 if (TREE_OPERAND (t
, 3))
3364 CHECK_OP (3, "invalid array stride");
3366 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3368 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3369 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3372 t
= TREE_OPERAND (t
, 0);
3375 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3377 error ("invalid reference prefix");
3389 case UNORDERED_EXPR
:
3400 case TRUNC_DIV_EXPR
:
3402 case FLOOR_DIV_EXPR
:
3403 case ROUND_DIV_EXPR
:
3404 case TRUNC_MOD_EXPR
:
3406 case FLOOR_MOD_EXPR
:
3407 case ROUND_MOD_EXPR
:
3409 case EXACT_DIV_EXPR
:
3419 CHECK_OP (0, "invalid operand to binary operator");
3420 CHECK_OP (1, "invalid operand to binary operator");
3424 if (TREE_CONSTANT (t
) && TREE_CODE (TREE_TYPE (t
)) == VECTOR_TYPE
)
3437 /* Verify STMT, return true if STMT is not in GIMPLE form.
3438 TODO: Implement type checking. */
3441 verify_stmt (tree stmt
, bool last_in_block
)
3445 if (OMP_DIRECTIVE_P (stmt
))
3447 /* OpenMP directives are validated by the FE and never operated
3448 on by the optimizers. Furthermore, OMP_FOR may contain
3449 non-gimple expressions when the main index variable has had
3450 its address taken. This does not affect the loop itself
3451 because the header of an OMP_FOR is merely used to determine
3452 how to setup the parallel iteration. */
3456 if (!is_gimple_stmt (stmt
))
3458 error ("is not a valid GIMPLE statement");
3462 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3465 debug_generic_stmt (addr
);
3469 /* If the statement is marked as part of an EH region, then it is
3470 expected that the statement could throw. Verify that when we
3471 have optimizations that simplify statements such that we prove
3472 that they cannot throw, that we update other data structures
3474 if (lookup_stmt_eh_region (stmt
) >= 0)
3476 if (!tree_could_throw_p (stmt
))
3478 error ("statement marked for throw, but doesn%'t");
3481 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3483 error ("statement marked for throw in middle of block");
3491 debug_generic_stmt (stmt
);
3496 /* Return true when the T can be shared. */
3499 tree_node_can_be_shared (tree t
)
3501 if (IS_TYPE_OR_DECL_P (t
)
3502 || is_gimple_min_invariant (t
)
3503 || TREE_CODE (t
) == SSA_NAME
3504 || t
== error_mark_node
3505 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3508 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3511 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3512 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3513 || TREE_CODE (t
) == COMPONENT_REF
3514 || TREE_CODE (t
) == REALPART_EXPR
3515 || TREE_CODE (t
) == IMAGPART_EXPR
)
3516 t
= TREE_OPERAND (t
, 0);
3525 /* Called via walk_trees. Verify tree sharing. */
3528 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3530 htab_t htab
= (htab_t
) data
;
3533 if (tree_node_can_be_shared (*tp
))
3535 *walk_subtrees
= false;
3539 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3541 return (tree
) *slot
;
3548 /* Helper function for verify_gimple_tuples. */
3551 verify_gimple_tuples_1 (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
3552 void *data ATTRIBUTE_UNUSED
)
3554 switch (TREE_CODE (*tp
))
3557 error ("unexpected non-tuple");
3567 /* Verify that there are no trees that should have been converted to
3568 gimple tuples. Return true if T contains a node that should have
3569 been converted to a gimple tuple, but hasn't. */
3572 verify_gimple_tuples (tree t
)
3574 return walk_tree (&t
, verify_gimple_tuples_1
, NULL
, NULL
) != NULL
;
3577 /* Verify the GIMPLE statement chain. */
3583 block_stmt_iterator bsi
;
3588 timevar_push (TV_TREE_STMT_VERIFY
);
3589 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3596 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3598 int phi_num_args
= PHI_NUM_ARGS (phi
);
3600 if (bb_for_stmt (phi
) != bb
)
3602 error ("bb_for_stmt (phi) is set to a wrong basic block");
3606 for (i
= 0; i
< phi_num_args
; i
++)
3608 tree t
= PHI_ARG_DEF (phi
, i
);
3611 /* Addressable variables do have SSA_NAMEs but they
3612 are not considered gimple values. */
3613 if (TREE_CODE (t
) != SSA_NAME
3614 && TREE_CODE (t
) != FUNCTION_DECL
3615 && !is_gimple_val (t
))
3617 error ("PHI def is not a GIMPLE value");
3618 debug_generic_stmt (phi
);
3619 debug_generic_stmt (t
);
3623 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3626 debug_generic_stmt (addr
);
3630 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3633 error ("incorrect sharing of tree nodes");
3634 debug_generic_stmt (phi
);
3635 debug_generic_stmt (addr
);
3641 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3643 tree stmt
= bsi_stmt (bsi
);
3645 err
|= verify_gimple_tuples (stmt
);
3647 if (bb_for_stmt (stmt
) != bb
)
3649 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3654 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3655 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3658 error ("incorrect sharing of tree nodes");
3659 debug_generic_stmt (stmt
);
3660 debug_generic_stmt (addr
);
3667 internal_error ("verify_stmts failed");
3670 timevar_pop (TV_TREE_STMT_VERIFY
);
3674 /* Verifies that the flow information is OK. */
3677 tree_verify_flow_info (void)
3681 block_stmt_iterator bsi
;
3686 if (ENTRY_BLOCK_PTR
->stmt_list
)
3688 error ("ENTRY_BLOCK has a statement list associated with it");
3692 if (EXIT_BLOCK_PTR
->stmt_list
)
3694 error ("EXIT_BLOCK has a statement list associated with it");
3698 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3699 if (e
->flags
& EDGE_FALLTHRU
)
3701 error ("fallthru to exit from bb %d", e
->src
->index
);
3707 bool found_ctrl_stmt
= false;
3711 /* Skip labels on the start of basic block. */
3712 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3714 tree prev_stmt
= stmt
;
3716 stmt
= bsi_stmt (bsi
);
3718 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3721 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3723 error ("nonlocal label ");
3724 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3725 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3730 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3733 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3734 fprintf (stderr
, " to block does not match in bb %d",
3739 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3740 != current_function_decl
)
3743 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3744 fprintf (stderr
, " has incorrect context in bb %d",
3750 /* Verify that body of basic block BB is free of control flow. */
3751 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3753 tree stmt
= bsi_stmt (bsi
);
3755 if (found_ctrl_stmt
)
3757 error ("control flow in the middle of basic block %d",
3762 if (stmt_ends_bb_p (stmt
))
3763 found_ctrl_stmt
= true;
3765 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3768 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3769 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3774 bsi
= bsi_last (bb
);
3775 if (bsi_end_p (bsi
))
3778 stmt
= bsi_stmt (bsi
);
3780 err
|= verify_eh_edges (stmt
);
3782 if (is_ctrl_stmt (stmt
))
3784 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3785 if (e
->flags
& EDGE_FALLTHRU
)
3787 error ("fallthru edge after a control statement in bb %d",
3793 if (TREE_CODE (stmt
) != COND_EXPR
)
3795 /* Verify that there are no edges with EDGE_TRUE/FALSE_FLAG set
3796 after anything else but if statement. */
3797 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3798 if (e
->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
))
3800 error ("true/false edge after a non-COND_EXPR in bb %d",
3806 switch (TREE_CODE (stmt
))
3812 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3813 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3815 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3819 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3821 if (!true_edge
|| !false_edge
3822 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3823 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3824 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3825 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3826 || EDGE_COUNT (bb
->succs
) >= 3)
3828 error ("wrong outgoing edge flags at end of bb %d",
3833 if (!has_label_p (true_edge
->dest
,
3834 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3836 error ("%<then%> label does not match edge at end of bb %d",
3841 if (!has_label_p (false_edge
->dest
,
3842 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3844 error ("%<else%> label does not match edge at end of bb %d",
3852 if (simple_goto_p (stmt
))
3854 error ("explicit goto at end of bb %d", bb
->index
);
3859 /* FIXME. We should double check that the labels in the
3860 destination blocks have their address taken. */
3861 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3862 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3863 | EDGE_FALSE_VALUE
))
3864 || !(e
->flags
& EDGE_ABNORMAL
))
3866 error ("wrong outgoing edge flags at end of bb %d",
3874 if (!single_succ_p (bb
)
3875 || (single_succ_edge (bb
)->flags
3876 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3877 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3879 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3882 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3884 error ("return edge does not point to exit in bb %d",
3897 vec
= SWITCH_LABELS (stmt
);
3898 n
= TREE_VEC_LENGTH (vec
);
3900 /* Mark all the destination basic blocks. */
3901 for (i
= 0; i
< n
; ++i
)
3903 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3904 basic_block label_bb
= label_to_block (lab
);
3906 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3907 label_bb
->aux
= (void *)1;
3910 /* Verify that the case labels are sorted. */
3911 prev
= TREE_VEC_ELT (vec
, 0);
3912 for (i
= 1; i
< n
- 1; ++i
)
3914 tree c
= TREE_VEC_ELT (vec
, i
);
3917 error ("found default case not at end of case vector");
3921 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3923 error ("case labels not sorted: ");
3924 print_generic_expr (stderr
, prev
, 0);
3925 fprintf (stderr
," is greater than ");
3926 print_generic_expr (stderr
, c
, 0);
3927 fprintf (stderr
," but comes before it.\n");
3932 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3934 error ("no default case found at end of case vector");
3938 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3942 error ("extra outgoing edge %d->%d",
3943 bb
->index
, e
->dest
->index
);
3946 e
->dest
->aux
= (void *)2;
3947 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3948 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3950 error ("wrong outgoing edge flags at end of bb %d",
3956 /* Check that we have all of them. */
3957 for (i
= 0; i
< n
; ++i
)
3959 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3960 basic_block label_bb
= label_to_block (lab
);
3962 if (label_bb
->aux
!= (void *)2)
3964 error ("missing edge %i->%i",
3965 bb
->index
, label_bb
->index
);
3970 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3971 e
->dest
->aux
= (void *)0;
3978 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3979 verify_dominators (CDI_DOMINATORS
);
3985 /* Updates phi nodes after creating a forwarder block joined
3986 by edge FALLTHRU. */
3989 tree_make_forwarder_block (edge fallthru
)
3993 basic_block dummy
, bb
;
3994 tree phi
, new_phi
, var
;
3996 dummy
= fallthru
->src
;
3997 bb
= fallthru
->dest
;
3999 if (single_pred_p (bb
))
4002 /* If we redirected a branch we must create new phi nodes at the
4004 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
4006 var
= PHI_RESULT (phi
);
4007 new_phi
= create_phi_node (var
, bb
);
4008 SSA_NAME_DEF_STMT (var
) = new_phi
;
4009 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
4010 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
4013 /* Ensure that the PHI node chain is in the same order. */
4014 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
4016 /* Add the arguments we have stored on edges. */
4017 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4022 flush_pending_stmts (e
);
4027 /* Return a non-special label in the head of basic block BLOCK.
4028 Create one if it doesn't exist. */
4031 tree_block_label (basic_block bb
)
4033 block_stmt_iterator i
, s
= bsi_start (bb
);
4037 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4039 stmt
= bsi_stmt (i
);
4040 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4042 label
= LABEL_EXPR_LABEL (stmt
);
4043 if (!DECL_NONLOCAL (label
))
4046 bsi_move_before (&i
, &s
);
4051 label
= create_artificial_label ();
4052 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4053 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4058 /* Attempt to perform edge redirection by replacing a possibly complex
4059 jump instruction by a goto or by removing the jump completely.
4060 This can apply only if all edges now point to the same block. The
4061 parameters and return values are equivalent to
4062 redirect_edge_and_branch. */
4065 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4067 basic_block src
= e
->src
;
4068 block_stmt_iterator b
;
4071 /* We can replace or remove a complex jump only when we have exactly
4073 if (EDGE_COUNT (src
->succs
) != 2
4074 /* Verify that all targets will be TARGET. Specifically, the
4075 edge that is not E must also go to TARGET. */
4076 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4082 stmt
= bsi_stmt (b
);
4084 if (TREE_CODE (stmt
) == COND_EXPR
4085 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4087 bsi_remove (&b
, true);
4088 e
= ssa_redirect_edge (e
, target
);
4089 e
->flags
= EDGE_FALLTHRU
;
4097 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4098 edge representing the redirected branch. */
4101 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4103 basic_block bb
= e
->src
;
4104 block_stmt_iterator bsi
;
4108 if (e
->flags
& EDGE_ABNORMAL
)
4111 if (e
->src
!= ENTRY_BLOCK_PTR
4112 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4115 if (e
->dest
== dest
)
4118 label
= tree_block_label (dest
);
4120 bsi
= bsi_last (bb
);
4121 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4123 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4126 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4127 ? COND_EXPR_THEN (stmt
)
4128 : COND_EXPR_ELSE (stmt
));
4129 GOTO_DESTINATION (stmt
) = label
;
4133 /* No non-abnormal edges should lead from a non-simple goto, and
4134 simple ones should be represented implicitly. */
4139 tree cases
= get_cases_for_edge (e
, stmt
);
4141 /* If we have a list of cases associated with E, then use it
4142 as it's a lot faster than walking the entire case vector. */
4145 edge e2
= find_edge (e
->src
, dest
);
4152 CASE_LABEL (cases
) = label
;
4153 cases
= TREE_CHAIN (cases
);
4156 /* If there was already an edge in the CFG, then we need
4157 to move all the cases associated with E to E2. */
4160 tree cases2
= get_cases_for_edge (e2
, stmt
);
4162 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4163 TREE_CHAIN (cases2
) = first
;
4168 tree vec
= SWITCH_LABELS (stmt
);
4169 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4171 for (i
= 0; i
< n
; i
++)
4173 tree elt
= TREE_VEC_ELT (vec
, i
);
4175 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4176 CASE_LABEL (elt
) = label
;
4184 bsi_remove (&bsi
, true);
4185 e
->flags
|= EDGE_FALLTHRU
;
4189 /* Otherwise it must be a fallthru edge, and we don't need to
4190 do anything besides redirecting it. */
4191 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4195 /* Update/insert PHI nodes as necessary. */
4197 /* Now update the edges in the CFG. */
4198 e
= ssa_redirect_edge (e
, dest
);
4204 /* Simple wrapper, as we can always redirect fallthru edges. */
4207 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4209 e
= tree_redirect_edge_and_branch (e
, dest
);
4216 /* Splits basic block BB after statement STMT (but at least after the
4217 labels). If STMT is NULL, BB is split just after the labels. */
4220 tree_split_block (basic_block bb
, void *stmt
)
4222 block_stmt_iterator bsi
;
4223 tree_stmt_iterator tsi_tgt
;
4229 new_bb
= create_empty_bb (bb
);
4231 /* Redirect the outgoing edges. */
4232 new_bb
->succs
= bb
->succs
;
4234 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4237 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4240 /* Move everything from BSI to the new basic block. */
4241 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4243 act
= bsi_stmt (bsi
);
4244 if (TREE_CODE (act
) == LABEL_EXPR
)
4257 if (bsi_end_p (bsi
))
4260 /* Split the statement list - avoid re-creating new containers as this
4261 brings ugly quadratic memory consumption in the inliner.
4262 (We are still quadratic since we need to update stmt BB pointers,
4264 new_bb
->stmt_list
= tsi_split_statement_list_before (&bsi
.tsi
);
4265 for (tsi_tgt
= tsi_start (new_bb
->stmt_list
);
4266 !tsi_end_p (tsi_tgt
); tsi_next (&tsi_tgt
))
4267 change_bb_for_stmt (tsi_stmt (tsi_tgt
), new_bb
);
4273 /* Moves basic block BB after block AFTER. */
4276 tree_move_block_after (basic_block bb
, basic_block after
)
4278 if (bb
->prev_bb
== after
)
4282 link_block (bb
, after
);
4288 /* Return true if basic_block can be duplicated. */
4291 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4297 /* Create a duplicate of the basic block BB. NOTE: This does not
4298 preserve SSA form. */
4301 tree_duplicate_bb (basic_block bb
)
4304 block_stmt_iterator bsi
, bsi_tgt
;
4307 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4309 /* Copy the PHI nodes. We ignore PHI node arguments here because
4310 the incoming edges have not been setup yet. */
4311 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4313 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4314 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4317 /* Keep the chain of PHI nodes in the same order so that they can be
4318 updated by ssa_redirect_edge. */
4319 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4321 bsi_tgt
= bsi_start (new_bb
);
4322 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4324 def_operand_p def_p
;
4325 ssa_op_iter op_iter
;
4329 stmt
= bsi_stmt (bsi
);
4330 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4333 /* Create a new copy of STMT and duplicate STMT's virtual
4335 copy
= unshare_expr (stmt
);
4336 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4337 copy_virtual_operands (copy
, stmt
);
4338 region
= lookup_stmt_eh_region (stmt
);
4340 add_stmt_to_eh_region (copy
, region
);
4342 /* Create new names for all the definitions created by COPY and
4343 add replacement mappings for each new name. */
4344 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4345 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4352 /* Basic block BB_COPY was created by code duplication. Add phi node
4353 arguments for edges going out of BB_COPY. The blocks that were
4354 duplicated have BB_DUPLICATED set. */
4357 add_phi_args_after_copy_bb (basic_block bb_copy
)
4359 basic_block bb
, dest
;
4362 tree phi
, phi_copy
, phi_next
, def
;
4364 bb
= get_bb_original (bb_copy
);
4366 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4368 if (!phi_nodes (e_copy
->dest
))
4371 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4372 dest
= get_bb_original (e_copy
->dest
);
4374 dest
= e_copy
->dest
;
4376 e
= find_edge (bb
, dest
);
4379 /* During loop unrolling the target of the latch edge is copied.
4380 In this case we are not looking for edge to dest, but to
4381 duplicated block whose original was dest. */
4382 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4383 if ((e
->dest
->flags
& BB_DUPLICATED
)
4384 && get_bb_original (e
->dest
) == dest
)
4387 gcc_assert (e
!= NULL
);
4390 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4392 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4394 phi_next
= PHI_CHAIN (phi
);
4395 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4396 add_phi_arg (phi_copy
, def
, e_copy
);
4401 /* Blocks in REGION_COPY array of length N_REGION were created by
4402 duplication of basic blocks. Add phi node arguments for edges
4403 going from these blocks. */
4406 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4410 for (i
= 0; i
< n_region
; i
++)
4411 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4413 for (i
= 0; i
< n_region
; i
++)
4414 add_phi_args_after_copy_bb (region_copy
[i
]);
4416 for (i
= 0; i
< n_region
; i
++)
4417 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4420 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4421 important exit edge EXIT. By important we mean that no SSA name defined
4422 inside region is live over the other exit edges of the region. All entry
4423 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4424 to the duplicate of the region. SSA form, dominance and loop information
4425 is updated. The new basic blocks are stored to REGION_COPY in the same
4426 order as they had in REGION, provided that REGION_COPY is not NULL.
4427 The function returns false if it is unable to copy the region,
4431 tree_duplicate_sese_region (edge entry
, edge exit
,
4432 basic_block
*region
, unsigned n_region
,
4433 basic_block
*region_copy
)
4436 bool free_region_copy
= false, copying_header
= false;
4437 struct loop
*loop
= entry
->dest
->loop_father
;
4441 int total_freq
= 0, entry_freq
= 0;
4442 gcov_type total_count
= 0, entry_count
= 0;
4444 if (!can_copy_bbs_p (region
, n_region
))
4447 /* Some sanity checking. Note that we do not check for all possible
4448 missuses of the functions. I.e. if you ask to copy something weird,
4449 it will work, but the state of structures probably will not be
4451 for (i
= 0; i
< n_region
; i
++)
4453 /* We do not handle subloops, i.e. all the blocks must belong to the
4455 if (region
[i
]->loop_father
!= loop
)
4458 if (region
[i
] != entry
->dest
4459 && region
[i
] == loop
->header
)
4465 /* In case the function is used for loop header copying (which is the primary
4466 use), ensure that EXIT and its copy will be new latch and entry edges. */
4467 if (loop
->header
== entry
->dest
)
4469 copying_header
= true;
4470 loop
->copy
= loop
->outer
;
4472 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4475 for (i
= 0; i
< n_region
; i
++)
4476 if (region
[i
] != exit
->src
4477 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4483 region_copy
= XNEWVEC (basic_block
, n_region
);
4484 free_region_copy
= true;
4487 gcc_assert (!need_ssa_update_p ());
4489 /* Record blocks outside the region that are dominated by something
4491 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4492 initialize_original_copy_tables ();
4494 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4496 if (entry
->dest
->count
)
4498 total_count
= entry
->dest
->count
;
4499 entry_count
= entry
->count
;
4500 /* Fix up corner cases, to avoid division by zero or creation of negative
4502 if (entry_count
> total_count
)
4503 entry_count
= total_count
;
4507 total_freq
= entry
->dest
->frequency
;
4508 entry_freq
= EDGE_FREQUENCY (entry
);
4509 /* Fix up corner cases, to avoid division by zero or creation of negative
4511 if (total_freq
== 0)
4513 else if (entry_freq
> total_freq
)
4514 entry_freq
= total_freq
;
4517 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4518 split_edge_bb_loc (entry
));
4521 scale_bbs_frequencies_gcov_type (region
, n_region
,
4522 total_count
- entry_count
,
4524 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4529 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4531 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4536 loop
->header
= exit
->dest
;
4537 loop
->latch
= exit
->src
;
4540 /* Redirect the entry and add the phi node arguments. */
4541 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4542 gcc_assert (redirected
!= NULL
);
4543 flush_pending_stmts (entry
);
4545 /* Concerning updating of dominators: We must recount dominators
4546 for entry block and its copy. Anything that is outside of the
4547 region, but was dominated by something inside needs recounting as
4549 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4550 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4551 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4554 /* Add the other PHI node arguments. */
4555 add_phi_args_after_copy (region_copy
, n_region
);
4557 /* Update the SSA web. */
4558 update_ssa (TODO_update_ssa
);
4560 if (free_region_copy
)
4563 free_original_copy_tables ();
4568 DEF_VEC_P(basic_block);
4569 DEF_VEC_ALLOC_P(basic_block,heap);
4572 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4573 adding blocks when the dominator traversal reaches EXIT. This
4574 function silently assumes that ENTRY strictly dominates EXIT. */
4577 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4578 VEC(basic_block
,heap
) **bbs_p
)
4582 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4584 son
= next_dom_son (CDI_DOMINATORS
, son
))
4586 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4588 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4598 bitmap vars_to_remove
;
4599 htab_t new_label_map
;
4603 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4604 contained in *TP and change the DECL_CONTEXT of every local
4605 variable referenced in *TP. */
4608 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4610 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4614 && (EXPR_P (t
) || GIMPLE_STMT_P (t
)))
4615 TREE_BLOCK (t
) = p
->block
;
4617 if (OMP_DIRECTIVE_P (t
)
4618 && TREE_CODE (t
) != OMP_RETURN
4619 && TREE_CODE (t
) != OMP_CONTINUE
)
4621 /* Do not remap variables inside OMP directives. Variables
4622 referenced in clauses and directive header belong to the
4623 parent function and should not be moved into the child
4625 bool save_remap_decls_p
= p
->remap_decls_p
;
4626 p
->remap_decls_p
= false;
4629 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4631 p
->remap_decls_p
= save_remap_decls_p
;
4633 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4635 if (TREE_CODE (t
) == LABEL_DECL
)
4637 if (p
->new_label_map
)
4639 struct tree_map in
, *out
;
4641 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4646 DECL_CONTEXT (t
) = p
->to_context
;
4648 else if (p
->remap_decls_p
)
4650 DECL_CONTEXT (t
) = p
->to_context
;
4652 if (TREE_CODE (t
) == VAR_DECL
)
4654 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4655 f
->unexpanded_var_list
4656 = tree_cons (0, t
, f
->unexpanded_var_list
);
4658 /* Mark T to be removed from the original function,
4659 otherwise it will be given a DECL_RTL when the
4660 original function is expanded. */
4661 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4665 else if (TYPE_P (t
))
4672 /* Move basic block BB from function CFUN to function DEST_FN. The
4673 block is moved out of the original linked list and placed after
4674 block AFTER in the new list. Also, the block is removed from the
4675 original array of blocks and placed in DEST_FN's array of blocks.
4676 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4677 updated to reflect the moved edges.
4679 On exit, local variables that need to be removed from
4680 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4683 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4684 basic_block after
, bool update_edge_count_p
,
4685 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4687 struct control_flow_graph
*cfg
;
4690 block_stmt_iterator si
;
4691 struct move_stmt_d d
;
4692 unsigned old_len
, new_len
;
4695 /* Link BB to the new linked list. */
4696 move_block_after (bb
, after
);
4698 /* Update the edge count in the corresponding flowgraphs. */
4699 if (update_edge_count_p
)
4700 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4702 cfun
->cfg
->x_n_edges
--;
4703 dest_cfun
->cfg
->x_n_edges
++;
4706 /* Remove BB from the original basic block array. */
4707 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4708 cfun
->cfg
->x_n_basic_blocks
--;
4710 /* Grow DEST_CFUN's basic block array if needed. */
4711 cfg
= dest_cfun
->cfg
;
4712 cfg
->x_n_basic_blocks
++;
4713 if (bb
->index
> cfg
->x_last_basic_block
)
4714 cfg
->x_last_basic_block
= bb
->index
;
4716 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4717 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4719 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4720 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4721 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4722 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4725 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4726 cfg
->x_last_basic_block
, bb
);
4728 /* The statements in BB need to be associated with a new TREE_BLOCK.
4729 Labels need to be associated with a new label-to-block map. */
4730 memset (&d
, 0, sizeof (d
));
4731 d
.vars_to_remove
= vars_to_remove
;
4733 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4735 tree stmt
= bsi_stmt (si
);
4738 d
.from_context
= cfun
->decl
;
4739 d
.to_context
= dest_cfun
->decl
;
4740 d
.remap_decls_p
= true;
4741 d
.new_label_map
= new_label_map
;
4742 if (TREE_BLOCK (stmt
))
4743 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4745 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4747 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4749 tree label
= LABEL_EXPR_LABEL (stmt
);
4750 int uid
= LABEL_DECL_UID (label
);
4752 gcc_assert (uid
> -1);
4754 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4755 if (old_len
<= (unsigned) uid
)
4757 new_len
= 3 * uid
/ 2;
4758 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4760 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4761 memset (&addr
[old_len
], 0,
4762 sizeof (basic_block
) * (new_len
- old_len
));
4765 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4766 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4768 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4770 if (uid
>= dest_cfun
->last_label_uid
)
4771 dest_cfun
->last_label_uid
= uid
+ 1;
4773 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4774 TREE_OPERAND (stmt
, 0) =
4775 build_int_cst (NULL_TREE
,
4776 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4779 region
= lookup_stmt_eh_region (stmt
);
4782 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4783 remove_stmt_from_eh_region (stmt
);
4788 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4789 the outermost EH region. Use REGION as the incoming base EH region. */
4792 find_outermost_region_in_block (struct function
*src_cfun
,
4793 basic_block bb
, int region
)
4795 block_stmt_iterator si
;
4797 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4799 tree stmt
= bsi_stmt (si
);
4802 if (TREE_CODE (stmt
) == RESX_EXPR
)
4803 stmt_region
= TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0));
4805 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4806 if (stmt_region
> 0)
4809 region
= stmt_region
;
4810 else if (stmt_region
!= region
)
4812 region
= eh_region_outermost (src_cfun
, stmt_region
, region
);
4813 gcc_assert (region
!= -1);
4822 new_label_mapper (tree decl
, void *data
)
4824 htab_t hash
= (htab_t
) data
;
4828 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4830 m
= xmalloc (sizeof (struct tree_map
));
4831 m
->hash
= DECL_UID (decl
);
4833 m
->to
= create_artificial_label ();
4834 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4836 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4837 gcc_assert (*slot
== NULL
);
4844 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4845 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4846 single basic block in the original CFG and the new basic block is
4847 returned. DEST_CFUN must not have a CFG yet.
4849 Note that the region need not be a pure SESE region. Blocks inside
4850 the region may contain calls to abort/exit. The only restriction
4851 is that ENTRY_BB should be the only entry point and it must
4854 All local variables referenced in the region are assumed to be in
4855 the corresponding BLOCK_VARS and unexpanded variable lists
4856 associated with DEST_CFUN. */
4859 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4860 basic_block exit_bb
)
4862 VEC(basic_block
,heap
) *bbs
;
4863 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4864 struct function
*saved_cfun
;
4865 int *entry_flag
, *exit_flag
, eh_offset
;
4866 unsigned i
, num_entry_edges
, num_exit_edges
;
4869 bitmap vars_to_remove
;
4870 htab_t new_label_map
;
4874 /* Collect all the blocks in the region. Manually add ENTRY_BB
4875 because it won't be added by dfs_enumerate_from. */
4876 calculate_dominance_info (CDI_DOMINATORS
);
4878 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4880 gcc_assert (entry_bb
!= exit_bb
4882 || dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
)));
4885 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4886 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4888 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4889 the predecessor edges to ENTRY_BB and the successor edges to
4890 EXIT_BB so that we can re-attach them to the new basic block that
4891 will replace the region. */
4892 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4893 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4894 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4896 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4898 entry_flag
[i
] = e
->flags
;
4899 entry_pred
[i
++] = e
->src
;
4905 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4906 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
,
4907 sizeof (basic_block
));
4908 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4910 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4912 exit_flag
[i
] = e
->flags
;
4913 exit_succ
[i
++] = e
->dest
;
4924 /* Switch context to the child function to initialize DEST_FN's CFG. */
4925 gcc_assert (dest_cfun
->cfg
== NULL
);
4928 init_empty_tree_cfg ();
4930 /* Initialize EH information for the new function. */
4932 new_label_map
= NULL
;
4937 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4938 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4940 init_eh_for_function ();
4943 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4944 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4945 new_label_map
, region
, 0);
4951 /* Move blocks from BBS into DEST_CFUN. */
4952 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4953 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4954 vars_to_remove
= BITMAP_ALLOC (NULL
);
4955 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4957 /* No need to update edge counts on the last block. It has
4958 already been updated earlier when we detached the region from
4959 the original CFG. */
4960 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4961 new_label_map
, eh_offset
);
4966 htab_delete (new_label_map
);
4968 /* Remove the variables marked in VARS_TO_REMOVE from
4969 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4970 DECL_RTL in the context of CFUN. */
4971 if (!bitmap_empty_p (vars_to_remove
))
4975 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4977 tree var
= TREE_VALUE (*p
);
4978 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4980 *p
= TREE_CHAIN (*p
);
4984 p
= &TREE_CHAIN (*p
);
4988 BITMAP_FREE (vars_to_remove
);
4990 /* Rewire the entry and exit blocks. The successor to the entry
4991 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4992 the child function. Similarly, the predecessor of DEST_FN's
4993 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4994 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4995 various CFG manipulation function get to the right CFG.
4997 FIXME, this is silly. The CFG ought to become a parameter to
5000 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
5002 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
5005 /* Back in the original function, the SESE region has disappeared,
5006 create a new basic block in its place. */
5007 bb
= create_empty_bb (entry_pred
[0]);
5008 for (i
= 0; i
< num_entry_edges
; i
++)
5009 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
5011 for (i
= 0; i
< num_exit_edges
; i
++)
5012 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
5021 free_dominance_info (CDI_DOMINATORS
);
5022 free_dominance_info (CDI_POST_DOMINATORS
);
5023 VEC_free (basic_block
, heap
, bbs
);
5029 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5032 dump_function_to_file (tree fn
, FILE *file
, int flags
)
5034 tree arg
, vars
, var
;
5035 bool ignore_topmost_bind
= false, any_var
= false;
5038 struct function
*saved_cfun
;
5040 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5042 arg
= DECL_ARGUMENTS (fn
);
5045 print_generic_expr (file
, arg
, dump_flags
);
5046 if (TREE_CHAIN (arg
))
5047 fprintf (file
, ", ");
5048 arg
= TREE_CHAIN (arg
);
5050 fprintf (file
, ")\n");
5052 if (flags
& TDF_DETAILS
)
5053 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
5054 if (flags
& TDF_RAW
)
5056 dump_node (fn
, TDF_SLIM
| flags
, file
);
5060 /* Switch CFUN to point to FN. */
5062 cfun
= DECL_STRUCT_FUNCTION (fn
);
5064 /* When GIMPLE is lowered, the variables are no longer available in
5065 BIND_EXPRs, so display them separately. */
5066 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
5068 ignore_topmost_bind
= true;
5070 fprintf (file
, "{\n");
5071 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5073 var
= TREE_VALUE (vars
);
5075 print_generic_decl (file
, var
, flags
);
5076 fprintf (file
, "\n");
5082 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
5084 /* Make a CFG based dump. */
5085 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5086 if (!ignore_topmost_bind
)
5087 fprintf (file
, "{\n");
5089 if (any_var
&& n_basic_blocks
)
5090 fprintf (file
, "\n");
5093 dump_generic_bb (file
, bb
, 2, flags
);
5095 fprintf (file
, "}\n");
5096 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5102 /* Make a tree based dump. */
5103 chain
= DECL_SAVED_TREE (fn
);
5105 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5107 if (ignore_topmost_bind
)
5109 chain
= BIND_EXPR_BODY (chain
);
5117 if (!ignore_topmost_bind
)
5118 fprintf (file
, "{\n");
5123 fprintf (file
, "\n");
5125 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5126 if (ignore_topmost_bind
)
5127 fprintf (file
, "}\n");
5130 fprintf (file
, "\n\n");
5137 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5140 debug_function (tree fn
, int flags
)
5142 dump_function_to_file (fn
, stderr
, flags
);
5146 /* Pretty print of the loops intermediate representation. */
5147 static void print_loop (FILE *, struct loop
*, int);
5148 static void print_pred_bbs (FILE *, basic_block bb
);
5149 static void print_succ_bbs (FILE *, basic_block bb
);
5152 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5155 print_pred_bbs (FILE *file
, basic_block bb
)
5160 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5161 fprintf (file
, "bb_%d ", e
->src
->index
);
5165 /* Print on FILE the indexes for the successors of basic_block BB. */
5168 print_succ_bbs (FILE *file
, basic_block bb
)
5173 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5174 fprintf (file
, "bb_%d ", e
->dest
->index
);
5178 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5181 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5189 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5190 memset ((void *) s_indent
, ' ', (size_t) indent
);
5191 s_indent
[indent
] = '\0';
5193 /* Print the loop's header. */
5194 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5196 /* Print the loop's body. */
5197 fprintf (file
, "%s{\n", s_indent
);
5199 if (bb
->loop_father
== loop
)
5201 /* Print the basic_block's header. */
5202 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5203 print_pred_bbs (file
, bb
);
5204 fprintf (file
, "}, succs = {");
5205 print_succ_bbs (file
, bb
);
5206 fprintf (file
, "})\n");
5208 /* Print the basic_block's body. */
5209 fprintf (file
, "%s {\n", s_indent
);
5210 tree_dump_bb (bb
, file
, indent
+ 4);
5211 fprintf (file
, "%s }\n", s_indent
);
5214 print_loop (file
, loop
->inner
, indent
+ 2);
5215 fprintf (file
, "%s}\n", s_indent
);
5216 print_loop (file
, loop
->next
, indent
);
5220 /* Follow a CFG edge from the entry point of the program, and on entry
5221 of a loop, pretty print the loop structure on FILE. */
5224 print_loop_ir (FILE *file
)
5228 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5229 if (bb
&& bb
->loop_father
)
5230 print_loop (file
, bb
->loop_father
, 0);
5234 /* Debugging loops structure at tree level. */
5237 debug_loop_ir (void)
5239 print_loop_ir (stderr
);
5243 /* Return true if BB ends with a call, possibly followed by some
5244 instructions that must stay with the call. Return false,
5248 tree_block_ends_with_call_p (basic_block bb
)
5250 block_stmt_iterator bsi
= bsi_last (bb
);
5251 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5255 /* Return true if BB ends with a conditional branch. Return false,
5259 tree_block_ends_with_condjump_p (basic_block bb
)
5261 tree stmt
= last_stmt (bb
);
5262 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5266 /* Return true if we need to add fake edge to exit at statement T.
5267 Helper function for tree_flow_call_edges_add. */
5270 need_fake_edge_p (tree t
)
5274 /* NORETURN and LONGJMP calls already have an edge to exit.
5275 CONST and PURE calls do not need one.
5276 We don't currently check for CONST and PURE here, although
5277 it would be a good idea, because those attributes are
5278 figured out from the RTL in mark_constant_function, and
5279 the counter incrementation code from -fprofile-arcs
5280 leads to different results from -fbranch-probabilities. */
5281 call
= get_call_expr_in (t
);
5283 && !(call_expr_flags (call
) & ECF_NORETURN
))
5286 if (TREE_CODE (t
) == ASM_EXPR
5287 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5294 /* Add fake edges to the function exit for any non constant and non
5295 noreturn calls, volatile inline assembly in the bitmap of blocks
5296 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5297 the number of blocks that were split.
5299 The goal is to expose cases in which entering a basic block does
5300 not imply that all subsequent instructions must be executed. */
5303 tree_flow_call_edges_add (sbitmap blocks
)
5306 int blocks_split
= 0;
5307 int last_bb
= last_basic_block
;
5308 bool check_last_block
= false;
5310 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5314 check_last_block
= true;
5316 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5318 /* In the last basic block, before epilogue generation, there will be
5319 a fallthru edge to EXIT. Special care is required if the last insn
5320 of the last basic block is a call because make_edge folds duplicate
5321 edges, which would result in the fallthru edge also being marked
5322 fake, which would result in the fallthru edge being removed by
5323 remove_fake_edges, which would result in an invalid CFG.
5325 Moreover, we can't elide the outgoing fake edge, since the block
5326 profiler needs to take this into account in order to solve the minimal
5327 spanning tree in the case that the call doesn't return.
5329 Handle this by adding a dummy instruction in a new last basic block. */
5330 if (check_last_block
)
5332 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5333 block_stmt_iterator bsi
= bsi_last (bb
);
5335 if (!bsi_end_p (bsi
))
5338 if (t
&& need_fake_edge_p (t
))
5342 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5345 bsi_insert_on_edge (e
, build_empty_stmt ());
5346 bsi_commit_edge_inserts ();
5351 /* Now add fake edges to the function exit for any non constant
5352 calls since there is no way that we can determine if they will
5354 for (i
= 0; i
< last_bb
; i
++)
5356 basic_block bb
= BASIC_BLOCK (i
);
5357 block_stmt_iterator bsi
;
5358 tree stmt
, last_stmt
;
5363 if (blocks
&& !TEST_BIT (blocks
, i
))
5366 bsi
= bsi_last (bb
);
5367 if (!bsi_end_p (bsi
))
5369 last_stmt
= bsi_stmt (bsi
);
5372 stmt
= bsi_stmt (bsi
);
5373 if (need_fake_edge_p (stmt
))
5376 /* The handling above of the final block before the
5377 epilogue should be enough to verify that there is
5378 no edge to the exit block in CFG already.
5379 Calling make_edge in such case would cause us to
5380 mark that edge as fake and remove it later. */
5381 #ifdef ENABLE_CHECKING
5382 if (stmt
== last_stmt
)
5384 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5385 gcc_assert (e
== NULL
);
5389 /* Note that the following may create a new basic block
5390 and renumber the existing basic blocks. */
5391 if (stmt
!= last_stmt
)
5393 e
= split_block (bb
, stmt
);
5397 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5401 while (!bsi_end_p (bsi
));
5406 verify_flow_info ();
5408 return blocks_split
;
5411 /* Purge dead abnormal call edges from basic block BB. */
5414 tree_purge_dead_abnormal_call_edges (basic_block bb
)
5416 bool changed
= tree_purge_dead_eh_edges (bb
);
5418 if (current_function_has_nonlocal_label
)
5420 tree stmt
= last_stmt (bb
);
5424 if (!(stmt
&& tree_can_make_abnormal_goto (stmt
)))
5425 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5427 if (e
->flags
& EDGE_ABNORMAL
)
5436 /* See tree_purge_dead_eh_edges below. */
5438 free_dominance_info (CDI_DOMINATORS
);
5444 /* Purge dead EH edges from basic block BB. */
5447 tree_purge_dead_eh_edges (basic_block bb
)
5449 bool changed
= false;
5452 tree stmt
= last_stmt (bb
);
5454 if (stmt
&& tree_can_throw_internal (stmt
))
5457 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5459 if (e
->flags
& EDGE_EH
)
5468 /* Removal of dead EH edges might change dominators of not
5469 just immediate successors. E.g. when bb1 is changed so that
5470 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5471 eh edges purged by this function in:
5483 idom(bb5) must be recomputed. For now just free the dominance
5486 free_dominance_info (CDI_DOMINATORS
);
5492 tree_purge_all_dead_eh_edges (bitmap blocks
)
5494 bool changed
= false;
5498 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5500 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5506 /* This function is called whenever a new edge is created or
5510 tree_execute_on_growing_pred (edge e
)
5512 basic_block bb
= e
->dest
;
5515 reserve_phi_args_for_new_edge (bb
);
5518 /* This function is called immediately before edge E is removed from
5519 the edge vector E->dest->preds. */
5522 tree_execute_on_shrinking_pred (edge e
)
5524 if (phi_nodes (e
->dest
))
5525 remove_phi_args (e
);
5528 /*---------------------------------------------------------------------------
5529 Helper functions for Loop versioning
5530 ---------------------------------------------------------------------------*/
5532 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5533 of 'first'. Both of them are dominated by 'new_head' basic block. When
5534 'new_head' was created by 'second's incoming edge it received phi arguments
5535 on the edge by split_edge(). Later, additional edge 'e' was created to
5536 connect 'new_head' and 'first'. Now this routine adds phi args on this
5537 additional edge 'e' that new_head to second edge received as part of edge
5542 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5543 basic_block new_head
, edge e
)
5546 edge e2
= find_edge (new_head
, second
);
5548 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5549 edge, we should always have an edge from NEW_HEAD to SECOND. */
5550 gcc_assert (e2
!= NULL
);
5552 /* Browse all 'second' basic block phi nodes and add phi args to
5553 edge 'e' for 'first' head. PHI args are always in correct order. */
5555 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5557 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5559 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5560 add_phi_arg (phi1
, def
, e
);
5564 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5565 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5566 the destination of the ELSE part. */
5568 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5569 basic_block cond_bb
, void *cond_e
)
5571 block_stmt_iterator bsi
;
5572 tree goto1
= NULL_TREE
;
5573 tree goto2
= NULL_TREE
;
5574 tree new_cond_expr
= NULL_TREE
;
5575 tree cond_expr
= (tree
) cond_e
;
5578 /* Build new conditional expr */
5579 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5580 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5581 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5583 /* Add new cond in cond_bb. */
5584 bsi
= bsi_start (cond_bb
);
5585 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5586 /* Adjust edges appropriately to connect new head with first head
5587 as well as second head. */
5588 e0
= single_succ_edge (cond_bb
);
5589 e0
->flags
&= ~EDGE_FALLTHRU
;
5590 e0
->flags
|= EDGE_FALSE_VALUE
;
5593 struct cfg_hooks tree_cfg_hooks
= {
5595 tree_verify_flow_info
,
5596 tree_dump_bb
, /* dump_bb */
5597 create_bb
, /* create_basic_block */
5598 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5599 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5600 remove_bb
, /* delete_basic_block */
5601 tree_split_block
, /* split_block */
5602 tree_move_block_after
, /* move_block_after */
5603 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5604 tree_merge_blocks
, /* merge_blocks */
5605 tree_predict_edge
, /* predict_edge */
5606 tree_predicted_by_p
, /* predicted_by_p */
5607 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5608 tree_duplicate_bb
, /* duplicate_block */
5609 tree_split_edge
, /* split_edge */
5610 tree_make_forwarder_block
, /* make_forward_block */
5611 NULL
, /* tidy_fallthru_edge */
5612 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5613 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5614 tree_flow_call_edges_add
, /* flow_call_edges_add */
5615 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5616 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5617 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5618 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5619 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5620 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5621 flush_pending_stmts
/* flush_pending_stmts */
5625 /* Split all critical edges. */
5628 split_critical_edges (void)
5634 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5635 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5636 mappings around the calls to split_edge. */
5637 start_recording_case_labels ();
5640 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5641 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5646 end_recording_case_labels ();
5650 struct tree_opt_pass pass_split_crit_edges
=
5652 "crited", /* name */
5654 split_critical_edges
, /* execute */
5657 0, /* static_pass_number */
5658 TV_TREE_SPLIT_EDGES
, /* tv_id */
5659 PROP_cfg
, /* properties required */
5660 PROP_no_crit_edges
, /* properties_provided */
5661 0, /* properties_destroyed */
5662 0, /* todo_flags_start */
5663 TODO_dump_func
, /* todo_flags_finish */
5668 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5669 a temporary, make sure and register it to be renamed if necessary,
5670 and finally return the temporary. Put the statements to compute
5671 EXP before the current statement in BSI. */
5674 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5676 tree t
, new_stmt
, orig_stmt
;
5678 if (is_gimple_val (exp
))
5681 t
= make_rename_temp (type
, NULL
);
5682 new_stmt
= build2_gimple (GIMPLE_MODIFY_STMT
, t
, exp
);
5684 orig_stmt
= bsi_stmt (*bsi
);
5685 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5686 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5688 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5689 if (gimple_in_ssa_p (cfun
))
5690 mark_new_vars_to_rename (new_stmt
);
5695 /* Build a ternary operation and gimplify it. Emit code before BSI.
5696 Return the gimple_val holding the result. */
5699 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5700 tree type
, tree a
, tree b
, tree c
)
5704 ret
= fold_build3 (code
, type
, a
, b
, c
);
5707 return gimplify_val (bsi
, type
, ret
);
5710 /* Build a binary operation and gimplify it. Emit code before BSI.
5711 Return the gimple_val holding the result. */
5714 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5715 tree type
, tree a
, tree b
)
5719 ret
= fold_build2 (code
, type
, a
, b
);
5722 return gimplify_val (bsi
, type
, ret
);
5725 /* Build a unary operation and gimplify it. Emit code before BSI.
5726 Return the gimple_val holding the result. */
5729 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5734 ret
= fold_build1 (code
, type
, a
);
5737 return gimplify_val (bsi
, type
, ret
);
5742 /* Emit return warnings. */
5745 execute_warn_function_return (void)
5747 #ifdef USE_MAPPED_LOCATION
5748 source_location location
;
5756 /* If we have a path to EXIT, then we do return. */
5757 if (TREE_THIS_VOLATILE (cfun
->decl
)
5758 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5760 #ifdef USE_MAPPED_LOCATION
5761 location
= UNKNOWN_LOCATION
;
5765 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5767 last
= last_stmt (e
->src
);
5768 if (TREE_CODE (last
) == RETURN_EXPR
5769 #ifdef USE_MAPPED_LOCATION
5770 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5772 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5776 #ifdef USE_MAPPED_LOCATION
5777 if (location
== UNKNOWN_LOCATION
)
5778 location
= cfun
->function_end_locus
;
5779 warning (0, "%H%<noreturn%> function does return", &location
);
5782 locus
= &cfun
->function_end_locus
;
5783 warning (0, "%H%<noreturn%> function does return", locus
);
5787 /* If we see "return;" in some basic block, then we do reach the end
5788 without returning a value. */
5789 else if (warn_return_type
5790 && !TREE_NO_WARNING (cfun
->decl
)
5791 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5792 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5794 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5796 tree last
= last_stmt (e
->src
);
5797 if (TREE_CODE (last
) == RETURN_EXPR
5798 && TREE_OPERAND (last
, 0) == NULL
5799 && !TREE_NO_WARNING (last
))
5801 #ifdef USE_MAPPED_LOCATION
5802 location
= EXPR_LOCATION (last
);
5803 if (location
== UNKNOWN_LOCATION
)
5804 location
= cfun
->function_end_locus
;
5805 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5807 locus
= EXPR_LOCUS (last
);
5809 locus
= &cfun
->function_end_locus
;
5810 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5812 TREE_NO_WARNING (cfun
->decl
) = 1;
5821 /* Given a basic block B which ends with a conditional and has
5822 precisely two successors, determine which of the edges is taken if
5823 the conditional is true and which is taken if the conditional is
5824 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5827 extract_true_false_edges_from_block (basic_block b
,
5831 edge e
= EDGE_SUCC (b
, 0);
5833 if (e
->flags
& EDGE_TRUE_VALUE
)
5836 *false_edge
= EDGE_SUCC (b
, 1);
5841 *true_edge
= EDGE_SUCC (b
, 1);
5845 struct tree_opt_pass pass_warn_function_return
=
5849 execute_warn_function_return
, /* execute */
5852 0, /* static_pass_number */
5854 PROP_cfg
, /* properties_required */
5855 0, /* properties_provided */
5856 0, /* properties_destroyed */
5857 0, /* todo_flags_start */
5858 0, /* todo_flags_finish */
5862 /* Emit noreturn warnings. */
5865 execute_warn_function_noreturn (void)
5867 if (warn_missing_noreturn
5868 && !TREE_THIS_VOLATILE (cfun
->decl
)
5869 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5870 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5871 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5872 "for attribute %<noreturn%>",
5877 struct tree_opt_pass pass_warn_function_noreturn
=
5881 execute_warn_function_noreturn
, /* execute */
5884 0, /* static_pass_number */
5886 PROP_cfg
, /* properties_required */
5887 0, /* properties_provided */
5888 0, /* properties_destroyed */
5889 0, /* todo_flags_start */
5890 0, /* todo_flags_finish */