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 void make_omp_sections_edges (basic_block
);
107 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
108 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
109 static unsigned int split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree
, tree
);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge
);
115 static void tree_cfg2vcg (FILE *);
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 (MODIFY_EXPR
, ptr_type_node
,
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. */
451 /* Create an edge from entry to the first block with executable
453 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
455 /* Traverse the basic block array placing edges. */
458 tree last
= last_stmt (bb
);
463 switch (TREE_CODE (last
))
466 make_goto_expr_edges (bb
);
470 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
474 make_cond_expr_edges (bb
);
478 make_switch_expr_edges (bb
);
482 make_eh_edges (last
);
487 /* If this function receives a nonlocal goto, then we need to
488 make edges from this call site to all the nonlocal goto
490 if (TREE_SIDE_EFFECTS (last
)
491 && current_function_has_nonlocal_label
)
492 make_goto_expr_edges (bb
);
494 /* If this statement has reachable exception handlers, then
495 create abnormal edges to them. */
496 make_eh_edges (last
);
498 /* Some calls are known not to return. */
499 fallthru
= !(call_expr_flags (last
) & ECF_NORETURN
);
503 if (is_ctrl_altering_stmt (last
))
505 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the
506 CALL_EXPR may have an abnormal edge. Search the RHS for
507 this case and create any required edges. */
508 tree op
= get_call_expr_in (last
);
509 if (op
&& TREE_SIDE_EFFECTS (op
)
510 && current_function_has_nonlocal_label
)
511 make_goto_expr_edges (bb
);
513 make_eh_edges (last
);
528 case OMP_RETURN_EXPR
:
529 /* In the case of an OMP_SECTION, we may have already made
530 an edge in make_omp_sections_edges. */
531 fallthru
= EDGE_COUNT (bb
->succs
) == 0;
535 make_omp_sections_edges (bb
);
540 gcc_assert (!stmt_ends_bb_p (last
));
548 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
551 /* Fold COND_EXPR_COND of each COND_EXPR. */
552 fold_cond_expr_cond ();
554 /* Clean up the graph and warn for unreachable code. */
559 /* Link an OMP_SECTIONS block to all the OMP_SECTION blocks in its body. */
562 make_omp_sections_edges (basic_block bb
)
568 stmt
= last_stmt (bb
);
569 vec
= OMP_SECTIONS_SECTIONS (stmt
);
570 n
= TREE_VEC_LENGTH (vec
);
571 exit_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, n
- 1));
573 for (i
= 0; i
< n
- 1; i
+= 2)
575 basic_block start_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, i
));
576 basic_block end_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, i
+ 1));
577 make_edge (bb
, start_bb
, 0);
578 make_edge (end_bb
, exit_bb
, EDGE_FALLTHRU
);
581 /* Once the CFG has been built, the vector of sections is no longer
582 useful. The region can be easily obtained with build_omp_regions.
583 Furthermore, this sharing of tree expressions is not allowed by the
584 statement verifier. */
585 OMP_SECTIONS_SECTIONS (stmt
) = NULL_TREE
;
588 /* Create the edges for a COND_EXPR starting at block BB.
589 At this point, both clauses must contain only simple gotos. */
592 make_cond_expr_edges (basic_block bb
)
594 tree entry
= last_stmt (bb
);
595 basic_block then_bb
, else_bb
;
596 tree then_label
, else_label
;
600 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
602 /* Entry basic blocks for each component. */
603 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
604 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
605 then_bb
= label_to_block (then_label
);
606 else_bb
= label_to_block (else_label
);
608 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
609 #ifdef USE_MAPPED_LOCATION
610 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
612 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
614 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
617 #ifdef USE_MAPPED_LOCATION
618 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
620 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
625 /* Hashing routine for EDGE_TO_CASES. */
628 edge_to_cases_hash (const void *p
)
630 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
632 /* Hash on the edge itself (which is a pointer). */
633 return htab_hash_pointer (e
);
636 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
637 for equality is just a pointer comparison. */
640 edge_to_cases_eq (const void *p1
, const void *p2
)
642 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
643 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
648 /* Called for each element in the hash table (P) as we delete the
649 edge to cases hash table.
651 Clear all the TREE_CHAINs to prevent problems with copying of
652 SWITCH_EXPRs and structure sharing rules, then free the hash table
656 edge_to_cases_cleanup (void *p
)
658 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
661 for (t
= elt
->case_labels
; t
; t
= next
)
663 next
= TREE_CHAIN (t
);
664 TREE_CHAIN (t
) = NULL
;
669 /* Start recording information mapping edges to case labels. */
672 start_recording_case_labels (void)
674 gcc_assert (edge_to_cases
== NULL
);
676 edge_to_cases
= htab_create (37,
679 edge_to_cases_cleanup
);
682 /* Return nonzero if we are recording information for case labels. */
685 recording_case_labels_p (void)
687 return (edge_to_cases
!= NULL
);
690 /* Stop recording information mapping edges to case labels and
691 remove any information we have recorded. */
693 end_recording_case_labels (void)
695 htab_delete (edge_to_cases
);
696 edge_to_cases
= NULL
;
699 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
702 record_switch_edge (edge e
, tree case_label
)
704 struct edge_to_cases_elt
*elt
;
707 /* Build a hash table element so we can see if E is already
709 elt
= XNEW (struct edge_to_cases_elt
);
711 elt
->case_labels
= case_label
;
713 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
717 /* E was not in the hash table. Install E into the hash table. */
722 /* E was already in the hash table. Free ELT as we do not need it
726 /* Get the entry stored in the hash table. */
727 elt
= (struct edge_to_cases_elt
*) *slot
;
729 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
730 TREE_CHAIN (case_label
) = elt
->case_labels
;
731 elt
->case_labels
= case_label
;
735 /* If we are inside a {start,end}_recording_cases block, then return
736 a chain of CASE_LABEL_EXPRs from T which reference E.
738 Otherwise return NULL. */
741 get_cases_for_edge (edge e
, tree t
)
743 struct edge_to_cases_elt elt
, *elt_p
;
748 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
749 chains available. Return NULL so the caller can detect this case. */
750 if (!recording_case_labels_p ())
755 elt
.case_labels
= NULL
;
756 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
760 elt_p
= (struct edge_to_cases_elt
*)*slot
;
761 return elt_p
->case_labels
;
764 /* If we did not find E in the hash table, then this must be the first
765 time we have been queried for information about E & T. Add all the
766 elements from T to the hash table then perform the query again. */
768 vec
= SWITCH_LABELS (t
);
769 n
= TREE_VEC_LENGTH (vec
);
770 for (i
= 0; i
< n
; i
++)
772 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
773 basic_block label_bb
= label_to_block (lab
);
774 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
779 /* Create the edges for a SWITCH_EXPR starting at block BB.
780 At this point, the switch body has been lowered and the
781 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
784 make_switch_expr_edges (basic_block bb
)
786 tree entry
= last_stmt (bb
);
790 vec
= SWITCH_LABELS (entry
);
791 n
= TREE_VEC_LENGTH (vec
);
793 for (i
= 0; i
< n
; ++i
)
795 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
796 basic_block label_bb
= label_to_block (lab
);
797 make_edge (bb
, label_bb
, 0);
802 /* Return the basic block holding label DEST. */
805 label_to_block_fn (struct function
*ifun
, tree dest
)
807 int uid
= LABEL_DECL_UID (dest
);
809 /* We would die hard when faced by an undefined label. Emit a label to
810 the very first basic block. This will hopefully make even the dataflow
811 and undefined variable warnings quite right. */
812 if ((errorcount
|| sorrycount
) && uid
< 0)
814 block_stmt_iterator bsi
=
815 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
818 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
819 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
820 uid
= LABEL_DECL_UID (dest
);
822 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
823 <= (unsigned int) uid
)
825 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
828 /* Create edges for a goto statement at block BB. */
831 make_goto_expr_edges (basic_block bb
)
834 basic_block target_bb
;
836 block_stmt_iterator last
= bsi_last (bb
);
838 goto_t
= bsi_stmt (last
);
840 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
841 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
842 from a nonlocal goto. */
843 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
847 tree dest
= GOTO_DESTINATION (goto_t
);
850 /* A GOTO to a local label creates normal edges. */
851 if (simple_goto_p (goto_t
))
853 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
854 #ifdef USE_MAPPED_LOCATION
855 e
->goto_locus
= EXPR_LOCATION (goto_t
);
857 e
->goto_locus
= EXPR_LOCUS (goto_t
);
859 bsi_remove (&last
, true);
863 /* Nothing more to do for nonlocal gotos. */
864 if (TREE_CODE (dest
) == LABEL_DECL
)
867 /* Computed gotos remain. */
870 /* Look for the block starting with the destination label. In the
871 case of a computed goto, make an edge to any label block we find
873 FOR_EACH_BB (target_bb
)
875 block_stmt_iterator bsi
;
877 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
879 tree target
= bsi_stmt (bsi
);
881 if (TREE_CODE (target
) != LABEL_EXPR
)
885 /* Computed GOTOs. Make an edge to every label block that has
886 been marked as a potential target for a computed goto. */
887 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && !for_call
)
888 /* Nonlocal GOTO target. Make an edge to every label block
889 that has been marked as a potential target for a nonlocal
891 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
))
893 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
901 /*---------------------------------------------------------------------------
903 ---------------------------------------------------------------------------*/
905 /* Cleanup useless labels in basic blocks. This is something we wish
906 to do early because it allows us to group case labels before creating
907 the edges for the CFG, and it speeds up block statement iterators in
909 We only run this pass once, running it more than once is probably not
912 /* A map from basic block index to the leading label of that block. */
913 static tree
*label_for_bb
;
915 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
917 update_eh_label (struct eh_region
*region
)
919 tree old_label
= get_eh_region_tree_label (region
);
923 basic_block bb
= label_to_block (old_label
);
925 /* ??? After optimizing, there may be EH regions with labels
926 that have already been removed from the function body, so
927 there is no basic block for them. */
931 new_label
= label_for_bb
[bb
->index
];
932 set_eh_region_tree_label (region
, new_label
);
936 /* Given LABEL return the first label in the same basic block. */
938 main_block_label (tree label
)
940 basic_block bb
= label_to_block (label
);
942 /* label_to_block possibly inserted undefined label into the chain. */
943 if (!label_for_bb
[bb
->index
])
944 label_for_bb
[bb
->index
] = label
;
945 return label_for_bb
[bb
->index
];
948 /* Cleanup redundant labels. This is a three-step process:
949 1) Find the leading label for each block.
950 2) Redirect all references to labels to the leading labels.
951 3) Cleanup all useless labels. */
954 cleanup_dead_labels (void)
957 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
959 /* Find a suitable label for each block. We use the first user-defined
960 label if there is one, or otherwise just the first label we see. */
963 block_stmt_iterator i
;
965 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
967 tree label
, stmt
= bsi_stmt (i
);
969 if (TREE_CODE (stmt
) != LABEL_EXPR
)
972 label
= LABEL_EXPR_LABEL (stmt
);
974 /* If we have not yet seen a label for the current block,
975 remember this one and see if there are more labels. */
976 if (! label_for_bb
[bb
->index
])
978 label_for_bb
[bb
->index
] = label
;
982 /* If we did see a label for the current block already, but it
983 is an artificially created label, replace it if the current
984 label is a user defined label. */
985 if (! DECL_ARTIFICIAL (label
)
986 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
988 label_for_bb
[bb
->index
] = label
;
994 /* Now redirect all jumps/branches to the selected label.
995 First do so for each block ending in a control statement. */
998 tree stmt
= last_stmt (bb
);
1002 switch (TREE_CODE (stmt
))
1006 tree true_branch
, false_branch
;
1008 true_branch
= COND_EXPR_THEN (stmt
);
1009 false_branch
= COND_EXPR_ELSE (stmt
);
1011 GOTO_DESTINATION (true_branch
)
1012 = main_block_label (GOTO_DESTINATION (true_branch
));
1013 GOTO_DESTINATION (false_branch
)
1014 = main_block_label (GOTO_DESTINATION (false_branch
));
1022 tree vec
= SWITCH_LABELS (stmt
);
1023 size_t n
= TREE_VEC_LENGTH (vec
);
1025 /* Replace all destination labels. */
1026 for (i
= 0; i
< n
; ++i
)
1028 tree elt
= TREE_VEC_ELT (vec
, i
);
1029 tree label
= main_block_label (CASE_LABEL (elt
));
1030 CASE_LABEL (elt
) = label
;
1035 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1036 remove them until after we've created the CFG edges. */
1038 if (! computed_goto_p (stmt
))
1040 GOTO_DESTINATION (stmt
)
1041 = main_block_label (GOTO_DESTINATION (stmt
));
1050 for_each_eh_region (update_eh_label
);
1052 /* Finally, purge dead labels. All user-defined labels and labels that
1053 can be the target of non-local gotos and labels which have their
1054 address taken are preserved. */
1057 block_stmt_iterator i
;
1058 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1060 if (! label_for_this_bb
)
1063 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1065 tree label
, stmt
= bsi_stmt (i
);
1067 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1070 label
= LABEL_EXPR_LABEL (stmt
);
1072 if (label
== label_for_this_bb
1073 || ! DECL_ARTIFICIAL (label
)
1074 || DECL_NONLOCAL (label
)
1075 || FORCED_LABEL (label
))
1078 bsi_remove (&i
, true);
1082 free (label_for_bb
);
1085 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1086 and scan the sorted vector of cases. Combine the ones jumping to the
1088 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1091 group_case_labels (void)
1097 tree stmt
= last_stmt (bb
);
1098 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1100 tree labels
= SWITCH_LABELS (stmt
);
1101 int old_size
= TREE_VEC_LENGTH (labels
);
1102 int i
, j
, new_size
= old_size
;
1103 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1106 /* The default label is always the last case in a switch
1107 statement after gimplification. */
1108 default_label
= CASE_LABEL (default_case
);
1110 /* Look for possible opportunities to merge cases.
1111 Ignore the last element of the label vector because it
1112 must be the default case. */
1114 while (i
< old_size
- 1)
1116 tree base_case
, base_label
, base_high
;
1117 base_case
= TREE_VEC_ELT (labels
, i
);
1119 gcc_assert (base_case
);
1120 base_label
= CASE_LABEL (base_case
);
1122 /* Discard cases that have the same destination as the
1124 if (base_label
== default_label
)
1126 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1132 base_high
= CASE_HIGH (base_case
) ?
1133 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1135 /* Try to merge case labels. Break out when we reach the end
1136 of the label vector or when we cannot merge the next case
1137 label with the current one. */
1138 while (i
< old_size
- 1)
1140 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1141 tree merge_label
= CASE_LABEL (merge_case
);
1142 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1143 integer_one_node
, 1);
1145 /* Merge the cases if they jump to the same place,
1146 and their ranges are consecutive. */
1147 if (merge_label
== base_label
1148 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1150 base_high
= CASE_HIGH (merge_case
) ?
1151 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1152 CASE_HIGH (base_case
) = base_high
;
1153 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1162 /* Compress the case labels in the label vector, and adjust the
1163 length of the vector. */
1164 for (i
= 0, j
= 0; i
< new_size
; i
++)
1166 while (! TREE_VEC_ELT (labels
, j
))
1168 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1170 TREE_VEC_LENGTH (labels
) = new_size
;
1175 /* Checks whether we can merge block B into block A. */
1178 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1181 block_stmt_iterator bsi
;
1184 if (!single_succ_p (a
))
1187 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1190 if (single_succ (a
) != b
)
1193 if (!single_pred_p (b
))
1196 if (b
== EXIT_BLOCK_PTR
)
1199 /* If A ends by a statement causing exceptions or something similar, we
1200 cannot merge the blocks. */
1201 stmt
= last_stmt (a
);
1202 if (stmt
&& stmt_ends_bb_p (stmt
))
1205 /* Do not allow a block with only a non-local label to be merged. */
1206 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1207 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1210 /* It must be possible to eliminate all phi nodes in B. If ssa form
1211 is not up-to-date, we cannot eliminate any phis. */
1212 phi
= phi_nodes (b
);
1215 if (need_ssa_update_p ())
1218 for (; phi
; phi
= PHI_CHAIN (phi
))
1219 if (!is_gimple_reg (PHI_RESULT (phi
))
1220 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1224 /* Do not remove user labels. */
1225 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1227 stmt
= bsi_stmt (bsi
);
1228 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1230 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1234 /* Protect the loop latches. */
1236 && b
->loop_father
->latch
== b
)
1242 /* Replaces all uses of NAME by VAL. */
1245 replace_uses_by (tree name
, tree val
)
1247 imm_use_iterator imm_iter
;
1252 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1254 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1256 stmt
= USE_STMT (use
);
1257 replace_exp (use
, val
);
1259 if (TREE_CODE (stmt
) == PHI_NODE
)
1261 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1262 if (e
->flags
& EDGE_ABNORMAL
)
1264 /* This can only occur for virtual operands, since
1265 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1266 would prevent replacement. */
1267 gcc_assert (!is_gimple_reg (name
));
1268 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1272 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1275 /* We do not update the statements in the loop above. Consider
1278 If we performed the update in the first loop, the statement
1279 would be rescanned after first occurrence of w is replaced,
1280 the new uses would be placed to the beginning of the list,
1281 and we would never process them. */
1282 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1286 fold_stmt_inplace (stmt
);
1288 rhs
= get_rhs (stmt
);
1289 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1290 recompute_tree_invariant_for_addr_expr (rhs
);
1292 maybe_clean_or_replace_eh_stmt (stmt
, stmt
);
1293 mark_new_vars_to_rename (stmt
);
1296 VEC_free (tree
, heap
, stmts
);
1298 /* Also update the trees stored in loop structures. */
1303 for (i
= 0; i
< current_loops
->num
; i
++)
1305 loop
= current_loops
->parray
[i
];
1307 substitute_in_loop_info (loop
, name
, val
);
1312 /* Merge block B into block A. */
1315 tree_merge_blocks (basic_block a
, basic_block b
)
1317 block_stmt_iterator bsi
;
1318 tree_stmt_iterator last
;
1322 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1324 /* Remove all single-valued PHI nodes from block B of the form
1325 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1327 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1329 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1331 bool may_replace_uses
= may_propagate_copy (def
, use
);
1333 /* In case we have loops to care about, do not propagate arguments of
1334 loop closed ssa phi nodes. */
1336 && is_gimple_reg (def
)
1337 && TREE_CODE (use
) == SSA_NAME
1338 && a
->loop_father
!= b
->loop_father
)
1339 may_replace_uses
= false;
1341 if (!may_replace_uses
)
1343 gcc_assert (is_gimple_reg (def
));
1345 /* Note that just emitting the copies is fine -- there is no problem
1346 with ordering of phi nodes. This is because A is the single
1347 predecessor of B, therefore results of the phi nodes cannot
1348 appear as arguments of the phi nodes. */
1349 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1350 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1351 SET_PHI_RESULT (phi
, NULL_TREE
);
1352 SSA_NAME_DEF_STMT (def
) = copy
;
1355 replace_uses_by (def
, use
);
1357 remove_phi_node (phi
, NULL
);
1360 /* Ensure that B follows A. */
1361 move_block_after (b
, a
);
1363 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1364 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1366 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1367 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1369 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1371 tree label
= bsi_stmt (bsi
);
1373 bsi_remove (&bsi
, false);
1374 /* Now that we can thread computed gotos, we might have
1375 a situation where we have a forced label in block B
1376 However, the label at the start of block B might still be
1377 used in other ways (think about the runtime checking for
1378 Fortran assigned gotos). So we can not just delete the
1379 label. Instead we move the label to the start of block A. */
1380 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1382 block_stmt_iterator dest_bsi
= bsi_start (a
);
1383 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1388 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1393 /* Merge the chains. */
1394 last
= tsi_last (a
->stmt_list
);
1395 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1396 b
->stmt_list
= NULL
;
1400 /* Return the one of two successors of BB that is not reachable by a
1401 reached by a complex edge, if there is one. Else, return BB. We use
1402 this in optimizations that use post-dominators for their heuristics,
1403 to catch the cases in C++ where function calls are involved. */
1406 single_noncomplex_succ (basic_block bb
)
1409 if (EDGE_COUNT (bb
->succs
) != 2)
1412 e0
= EDGE_SUCC (bb
, 0);
1413 e1
= EDGE_SUCC (bb
, 1);
1414 if (e0
->flags
& EDGE_COMPLEX
)
1416 if (e1
->flags
& EDGE_COMPLEX
)
1424 /* Walk the function tree removing unnecessary statements.
1426 * Empty statement nodes are removed
1428 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1430 * Unnecessary COND_EXPRs are removed
1432 * Some unnecessary BIND_EXPRs are removed
1434 Clearly more work could be done. The trick is doing the analysis
1435 and removal fast enough to be a net improvement in compile times.
1437 Note that when we remove a control structure such as a COND_EXPR
1438 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1439 to ensure we eliminate all the useless code. */
1450 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1453 remove_useless_stmts_warn_notreached (tree stmt
)
1455 if (EXPR_HAS_LOCATION (stmt
))
1457 location_t loc
= EXPR_LOCATION (stmt
);
1458 if (LOCATION_LINE (loc
) > 0)
1460 warning (0, "%Hwill never be executed", &loc
);
1465 switch (TREE_CODE (stmt
))
1467 case STATEMENT_LIST
:
1469 tree_stmt_iterator i
;
1470 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1471 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1477 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1479 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1481 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1485 case TRY_FINALLY_EXPR
:
1486 case TRY_CATCH_EXPR
:
1487 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1489 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1494 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1495 case EH_FILTER_EXPR
:
1496 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1498 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1501 /* Not a live container. */
1509 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1511 tree then_clause
, else_clause
, cond
;
1512 bool save_has_label
, then_has_label
, else_has_label
;
1514 save_has_label
= data
->has_label
;
1515 data
->has_label
= false;
1516 data
->last_goto
= NULL
;
1518 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1520 then_has_label
= data
->has_label
;
1521 data
->has_label
= false;
1522 data
->last_goto
= NULL
;
1524 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1526 else_has_label
= data
->has_label
;
1527 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1529 then_clause
= COND_EXPR_THEN (*stmt_p
);
1530 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1531 cond
= fold (COND_EXPR_COND (*stmt_p
));
1533 /* If neither arm does anything at all, we can remove the whole IF. */
1534 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1536 *stmt_p
= build_empty_stmt ();
1537 data
->repeat
= true;
1540 /* If there are no reachable statements in an arm, then we can
1541 zap the entire conditional. */
1542 else if (integer_nonzerop (cond
) && !else_has_label
)
1544 if (warn_notreached
)
1545 remove_useless_stmts_warn_notreached (else_clause
);
1546 *stmt_p
= then_clause
;
1547 data
->repeat
= true;
1549 else if (integer_zerop (cond
) && !then_has_label
)
1551 if (warn_notreached
)
1552 remove_useless_stmts_warn_notreached (then_clause
);
1553 *stmt_p
= else_clause
;
1554 data
->repeat
= true;
1557 /* Check a couple of simple things on then/else with single stmts. */
1560 tree then_stmt
= expr_only (then_clause
);
1561 tree else_stmt
= expr_only (else_clause
);
1563 /* Notice branches to a common destination. */
1564 if (then_stmt
&& else_stmt
1565 && TREE_CODE (then_stmt
) == GOTO_EXPR
1566 && TREE_CODE (else_stmt
) == GOTO_EXPR
1567 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1569 *stmt_p
= then_stmt
;
1570 data
->repeat
= true;
1573 /* If the THEN/ELSE clause merely assigns a value to a variable or
1574 parameter which is already known to contain that value, then
1575 remove the useless THEN/ELSE clause. */
1576 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1579 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1580 && TREE_OPERAND (else_stmt
, 0) == cond
1581 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1582 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1584 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1585 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1586 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1587 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1589 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1590 ? then_stmt
: else_stmt
);
1591 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1592 ? &COND_EXPR_THEN (*stmt_p
)
1593 : &COND_EXPR_ELSE (*stmt_p
));
1596 && TREE_CODE (stmt
) == MODIFY_EXPR
1597 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1598 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1599 *location
= alloc_stmt_list ();
1603 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1604 would be re-introduced during lowering. */
1605 data
->last_goto
= NULL
;
1610 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1612 bool save_may_branch
, save_may_throw
;
1613 bool this_may_branch
, this_may_throw
;
1615 /* Collect may_branch and may_throw information for the body only. */
1616 save_may_branch
= data
->may_branch
;
1617 save_may_throw
= data
->may_throw
;
1618 data
->may_branch
= false;
1619 data
->may_throw
= false;
1620 data
->last_goto
= NULL
;
1622 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1624 this_may_branch
= data
->may_branch
;
1625 this_may_throw
= data
->may_throw
;
1626 data
->may_branch
|= save_may_branch
;
1627 data
->may_throw
|= save_may_throw
;
1628 data
->last_goto
= NULL
;
1630 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1632 /* If the body is empty, then we can emit the FINALLY block without
1633 the enclosing TRY_FINALLY_EXPR. */
1634 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1636 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1637 data
->repeat
= true;
1640 /* If the handler is empty, then we can emit the TRY block without
1641 the enclosing TRY_FINALLY_EXPR. */
1642 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1644 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1645 data
->repeat
= true;
1648 /* If the body neither throws, nor branches, then we can safely
1649 string the TRY and FINALLY blocks together. */
1650 else if (!this_may_branch
&& !this_may_throw
)
1652 tree stmt
= *stmt_p
;
1653 *stmt_p
= TREE_OPERAND (stmt
, 0);
1654 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1655 data
->repeat
= true;
1661 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1663 bool save_may_throw
, this_may_throw
;
1664 tree_stmt_iterator i
;
1667 /* Collect may_throw information for the body only. */
1668 save_may_throw
= data
->may_throw
;
1669 data
->may_throw
= false;
1670 data
->last_goto
= NULL
;
1672 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1674 this_may_throw
= data
->may_throw
;
1675 data
->may_throw
= save_may_throw
;
1677 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1678 if (!this_may_throw
)
1680 if (warn_notreached
)
1681 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1682 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1683 data
->repeat
= true;
1687 /* Process the catch clause specially. We may be able to tell that
1688 no exceptions propagate past this point. */
1690 this_may_throw
= true;
1691 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1692 stmt
= tsi_stmt (i
);
1693 data
->last_goto
= NULL
;
1695 switch (TREE_CODE (stmt
))
1698 for (; !tsi_end_p (i
); tsi_next (&i
))
1700 stmt
= tsi_stmt (i
);
1701 /* If we catch all exceptions, then the body does not
1702 propagate exceptions past this point. */
1703 if (CATCH_TYPES (stmt
) == NULL
)
1704 this_may_throw
= false;
1705 data
->last_goto
= NULL
;
1706 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1710 case EH_FILTER_EXPR
:
1711 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1712 this_may_throw
= false;
1713 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1714 this_may_throw
= false;
1715 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1719 /* Otherwise this is a cleanup. */
1720 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1722 /* If the cleanup is empty, then we can emit the TRY block without
1723 the enclosing TRY_CATCH_EXPR. */
1724 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1726 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1727 data
->repeat
= true;
1731 data
->may_throw
|= this_may_throw
;
1736 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1740 /* First remove anything underneath the BIND_EXPR. */
1741 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1743 /* If the BIND_EXPR has no variables, then we can pull everything
1744 up one level and remove the BIND_EXPR, unless this is the toplevel
1745 BIND_EXPR for the current function or an inlined function.
1747 When this situation occurs we will want to apply this
1748 optimization again. */
1749 block
= BIND_EXPR_BLOCK (*stmt_p
);
1750 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1751 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1753 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1754 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1757 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1758 data
->repeat
= true;
1764 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1766 tree dest
= GOTO_DESTINATION (*stmt_p
);
1768 data
->may_branch
= true;
1769 data
->last_goto
= NULL
;
1771 /* Record the last goto expr, so that we can delete it if unnecessary. */
1772 if (TREE_CODE (dest
) == LABEL_DECL
)
1773 data
->last_goto
= stmt_p
;
1778 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1780 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1782 data
->has_label
= true;
1784 /* We do want to jump across non-local label receiver code. */
1785 if (DECL_NONLOCAL (label
))
1786 data
->last_goto
= NULL
;
1788 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1790 *data
->last_goto
= build_empty_stmt ();
1791 data
->repeat
= true;
1794 /* ??? Add something here to delete unused labels. */
1798 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1799 decl. This allows us to eliminate redundant or useless
1800 calls to "const" functions.
1802 Gimplifier already does the same operation, but we may notice functions
1803 being const and pure once their calls has been gimplified, so we need
1804 to update the flag. */
1807 update_call_expr_flags (tree call
)
1809 tree decl
= get_callee_fndecl (call
);
1812 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1813 TREE_SIDE_EFFECTS (call
) = 0;
1814 if (TREE_NOTHROW (decl
))
1815 TREE_NOTHROW (call
) = 1;
1819 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1822 notice_special_calls (tree t
)
1824 int flags
= call_expr_flags (t
);
1826 if (flags
& ECF_MAY_BE_ALLOCA
)
1827 current_function_calls_alloca
= true;
1828 if (flags
& ECF_RETURNS_TWICE
)
1829 current_function_calls_setjmp
= true;
1833 /* Clear flags set by notice_special_calls. Used by dead code removal
1834 to update the flags. */
1837 clear_special_calls (void)
1839 current_function_calls_alloca
= false;
1840 current_function_calls_setjmp
= false;
1845 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1849 switch (TREE_CODE (t
))
1852 remove_useless_stmts_cond (tp
, data
);
1855 case TRY_FINALLY_EXPR
:
1856 remove_useless_stmts_tf (tp
, data
);
1859 case TRY_CATCH_EXPR
:
1860 remove_useless_stmts_tc (tp
, data
);
1864 remove_useless_stmts_bind (tp
, data
);
1868 remove_useless_stmts_goto (tp
, data
);
1872 remove_useless_stmts_label (tp
, data
);
1877 data
->last_goto
= NULL
;
1878 data
->may_branch
= true;
1883 data
->last_goto
= NULL
;
1884 notice_special_calls (t
);
1885 update_call_expr_flags (t
);
1886 if (tree_could_throw_p (t
))
1887 data
->may_throw
= true;
1891 data
->last_goto
= NULL
;
1893 op
= get_call_expr_in (t
);
1896 update_call_expr_flags (op
);
1897 notice_special_calls (op
);
1899 if (tree_could_throw_p (t
))
1900 data
->may_throw
= true;
1903 case STATEMENT_LIST
:
1905 tree_stmt_iterator i
= tsi_start (t
);
1906 while (!tsi_end_p (i
))
1909 if (IS_EMPTY_STMT (t
))
1915 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1918 if (TREE_CODE (t
) == STATEMENT_LIST
)
1920 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1930 data
->last_goto
= NULL
;
1934 data
->last_goto
= NULL
;
1940 remove_useless_stmts (void)
1942 struct rus_data data
;
1944 clear_special_calls ();
1948 memset (&data
, 0, sizeof (data
));
1949 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1951 while (data
.repeat
);
1956 struct tree_opt_pass pass_remove_useless_stmts
=
1958 "useless", /* name */
1960 remove_useless_stmts
, /* execute */
1963 0, /* static_pass_number */
1965 PROP_gimple_any
, /* properties_required */
1966 0, /* properties_provided */
1967 0, /* properties_destroyed */
1968 0, /* todo_flags_start */
1969 TODO_dump_func
, /* todo_flags_finish */
1973 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1976 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1980 /* Since this block is no longer reachable, we can just delete all
1981 of its PHI nodes. */
1982 phi
= phi_nodes (bb
);
1985 tree next
= PHI_CHAIN (phi
);
1986 remove_phi_node (phi
, NULL_TREE
);
1990 /* Remove edges to BB's successors. */
1991 while (EDGE_COUNT (bb
->succs
) > 0)
1992 remove_edge (EDGE_SUCC (bb
, 0));
1996 /* Remove statements of basic block BB. */
1999 remove_bb (basic_block bb
)
2001 block_stmt_iterator i
;
2002 #ifdef USE_MAPPED_LOCATION
2003 source_location loc
= UNKNOWN_LOCATION
;
2005 source_locus loc
= 0;
2010 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2011 if (dump_flags
& TDF_DETAILS
)
2013 dump_bb (bb
, dump_file
, 0);
2014 fprintf (dump_file
, "\n");
2018 /* If we remove the header or the latch of a loop, mark the loop for
2019 removal by setting its header and latch to NULL. */
2022 struct loop
*loop
= bb
->loop_father
;
2024 if (loop
->latch
== bb
2025 || loop
->header
== bb
)
2028 loop
->header
= NULL
;
2030 /* Also clean up the information associated with the loop. Updating
2031 it would waste time. More importantly, it may refer to ssa
2032 names that were defined in other removed basic block -- these
2033 ssa names are now removed and invalid. */
2034 free_numbers_of_iterations_estimates_loop (loop
);
2038 /* Remove all the instructions in the block. */
2039 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2041 tree stmt
= bsi_stmt (i
);
2042 if (TREE_CODE (stmt
) == LABEL_EXPR
2043 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2044 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2047 block_stmt_iterator new_bsi
;
2049 /* A non-reachable non-local label may still be referenced.
2050 But it no longer needs to carry the extra semantics of
2052 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2054 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2055 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2058 new_bb
= bb
->prev_bb
;
2059 new_bsi
= bsi_start (new_bb
);
2060 bsi_remove (&i
, false);
2061 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2065 /* Release SSA definitions if we are in SSA. Note that we
2066 may be called when not in SSA. For example,
2067 final_cleanup calls this function via
2068 cleanup_tree_cfg. */
2070 release_defs (stmt
);
2072 bsi_remove (&i
, true);
2075 /* Don't warn for removed gotos. Gotos are often removed due to
2076 jump threading, thus resulting in bogus warnings. Not great,
2077 since this way we lose warnings for gotos in the original
2078 program that are indeed unreachable. */
2079 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2081 #ifdef USE_MAPPED_LOCATION
2082 if (EXPR_HAS_LOCATION (stmt
))
2083 loc
= EXPR_LOCATION (stmt
);
2086 t
= EXPR_LOCUS (stmt
);
2087 if (t
&& LOCATION_LINE (*t
) > 0)
2093 /* If requested, give a warning that the first statement in the
2094 block is unreachable. We walk statements backwards in the
2095 loop above, so the last statement we process is the first statement
2097 #ifdef USE_MAPPED_LOCATION
2098 if (loc
> BUILTINS_LOCATION
)
2099 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2102 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2105 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2109 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2110 predicate VAL, return the edge that will be taken out of the block.
2111 If VAL does not match a unique edge, NULL is returned. */
2114 find_taken_edge (basic_block bb
, tree val
)
2118 stmt
= last_stmt (bb
);
2121 gcc_assert (is_ctrl_stmt (stmt
));
2124 if (! is_gimple_min_invariant (val
))
2127 if (TREE_CODE (stmt
) == COND_EXPR
)
2128 return find_taken_edge_cond_expr (bb
, val
);
2130 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2131 return find_taken_edge_switch_expr (bb
, val
);
2133 if (computed_goto_p (stmt
))
2134 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2139 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2140 statement, determine which of the outgoing edges will be taken out of the
2141 block. Return NULL if either edge may be taken. */
2144 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2149 dest
= label_to_block (val
);
2152 e
= find_edge (bb
, dest
);
2153 gcc_assert (e
!= NULL
);
2159 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2160 statement, determine which of the two edges will be taken out of the
2161 block. Return NULL if either edge may be taken. */
2164 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2166 edge true_edge
, false_edge
;
2168 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2170 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2171 return (zero_p (val
) ? false_edge
: true_edge
);
2174 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2175 statement, determine which edge will be taken out of the block. Return
2176 NULL if any edge may be taken. */
2179 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2181 tree switch_expr
, taken_case
;
2182 basic_block dest_bb
;
2185 switch_expr
= last_stmt (bb
);
2186 taken_case
= find_case_label_for_value (switch_expr
, val
);
2187 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2189 e
= find_edge (bb
, dest_bb
);
2195 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2196 We can make optimal use here of the fact that the case labels are
2197 sorted: We can do a binary search for a case matching VAL. */
2200 find_case_label_for_value (tree switch_expr
, tree val
)
2202 tree vec
= SWITCH_LABELS (switch_expr
);
2203 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2204 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2206 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2208 size_t i
= (high
+ low
) / 2;
2209 tree t
= TREE_VEC_ELT (vec
, i
);
2212 /* Cache the result of comparing CASE_LOW and val. */
2213 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2220 if (CASE_HIGH (t
) == NULL
)
2222 /* A singe-valued case label. */
2228 /* A case range. We can only handle integer ranges. */
2229 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2234 return default_case
;
2240 /*---------------------------------------------------------------------------
2242 ---------------------------------------------------------------------------*/
2244 /* Dump tree-specific information of block BB to file OUTF. */
2247 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2249 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2253 /* Dump a basic block on stderr. */
2256 debug_tree_bb (basic_block bb
)
2258 dump_bb (bb
, stderr
, 0);
2262 /* Dump basic block with index N on stderr. */
2265 debug_tree_bb_n (int n
)
2267 debug_tree_bb (BASIC_BLOCK (n
));
2268 return BASIC_BLOCK (n
);
2272 /* Dump the CFG on stderr.
2274 FLAGS are the same used by the tree dumping functions
2275 (see TDF_* in tree.h). */
2278 debug_tree_cfg (int flags
)
2280 dump_tree_cfg (stderr
, flags
);
2284 /* Dump the program showing basic block boundaries on the given FILE.
2286 FLAGS are the same used by the tree dumping functions (see TDF_* in
2290 dump_tree_cfg (FILE *file
, int flags
)
2292 if (flags
& TDF_DETAILS
)
2294 const char *funcname
2295 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2298 fprintf (file
, ";; Function %s\n\n", funcname
);
2299 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2300 n_basic_blocks
, n_edges
, last_basic_block
);
2302 brief_dump_cfg (file
);
2303 fprintf (file
, "\n");
2306 if (flags
& TDF_STATS
)
2307 dump_cfg_stats (file
);
2309 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2313 /* Dump CFG statistics on FILE. */
2316 dump_cfg_stats (FILE *file
)
2318 static long max_num_merged_labels
= 0;
2319 unsigned long size
, total
= 0;
2322 const char * const fmt_str
= "%-30s%-13s%12s\n";
2323 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2324 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2325 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2326 const char *funcname
2327 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2330 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2332 fprintf (file
, "---------------------------------------------------------\n");
2333 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2334 fprintf (file
, fmt_str
, "", " instances ", "used ");
2335 fprintf (file
, "---------------------------------------------------------\n");
2337 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2339 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2340 SCALE (size
), LABEL (size
));
2344 num_edges
+= EDGE_COUNT (bb
->succs
);
2345 size
= num_edges
* sizeof (struct edge_def
);
2347 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2349 fprintf (file
, "---------------------------------------------------------\n");
2350 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2352 fprintf (file
, "---------------------------------------------------------\n");
2353 fprintf (file
, "\n");
2355 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2356 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2358 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2359 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2361 fprintf (file
, "\n");
2365 /* Dump CFG statistics on stderr. Keep extern so that it's always
2366 linked in the final executable. */
2369 debug_cfg_stats (void)
2371 dump_cfg_stats (stderr
);
2375 /* Dump the flowgraph to a .vcg FILE. */
2378 tree_cfg2vcg (FILE *file
)
2383 const char *funcname
2384 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2386 /* Write the file header. */
2387 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2388 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2389 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2391 /* Write blocks and edges. */
2392 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2394 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2397 if (e
->flags
& EDGE_FAKE
)
2398 fprintf (file
, " linestyle: dotted priority: 10");
2400 fprintf (file
, " linestyle: solid priority: 100");
2402 fprintf (file
, " }\n");
2408 enum tree_code head_code
, end_code
;
2409 const char *head_name
, *end_name
;
2412 tree first
= first_stmt (bb
);
2413 tree last
= last_stmt (bb
);
2417 head_code
= TREE_CODE (first
);
2418 head_name
= tree_code_name
[head_code
];
2419 head_line
= get_lineno (first
);
2422 head_name
= "no-statement";
2426 end_code
= TREE_CODE (last
);
2427 end_name
= tree_code_name
[end_code
];
2428 end_line
= get_lineno (last
);
2431 end_name
= "no-statement";
2433 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2434 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2437 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2439 if (e
->dest
== EXIT_BLOCK_PTR
)
2440 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2442 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2444 if (e
->flags
& EDGE_FAKE
)
2445 fprintf (file
, " priority: 10 linestyle: dotted");
2447 fprintf (file
, " priority: 100 linestyle: solid");
2449 fprintf (file
, " }\n");
2452 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2456 fputs ("}\n\n", file
);
2461 /*---------------------------------------------------------------------------
2462 Miscellaneous helpers
2463 ---------------------------------------------------------------------------*/
2465 /* Return true if T represents a stmt that always transfers control. */
2468 is_ctrl_stmt (tree t
)
2470 return (TREE_CODE (t
) == COND_EXPR
2471 || TREE_CODE (t
) == SWITCH_EXPR
2472 || TREE_CODE (t
) == GOTO_EXPR
2473 || TREE_CODE (t
) == RETURN_EXPR
2474 || TREE_CODE (t
) == RESX_EXPR
);
2478 /* Return true if T is a statement that may alter the flow of control
2479 (e.g., a call to a non-returning function). */
2482 is_ctrl_altering_stmt (tree t
)
2487 call
= get_call_expr_in (t
);
2490 /* A non-pure/const CALL_EXPR alters flow control if the current
2491 function has nonlocal labels. */
2492 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2495 /* A CALL_EXPR also alters control flow if it does not return. */
2496 if (call_expr_flags (call
) & ECF_NORETURN
)
2500 /* OpenMP directives alter control flow. */
2501 if (flag_openmp
&& OMP_DIRECTIVE_P (t
))
2504 /* If a statement can throw, it alters control flow. */
2505 return tree_can_throw_internal (t
);
2509 /* Return true if T is a computed goto. */
2512 computed_goto_p (tree t
)
2514 return (TREE_CODE (t
) == GOTO_EXPR
2515 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2519 /* Checks whether EXPR is a simple local goto. */
2522 simple_goto_p (tree expr
)
2524 return (TREE_CODE (expr
) == GOTO_EXPR
2525 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2529 /* Return true if T should start a new basic block. PREV_T is the
2530 statement preceding T. It is used when T is a label or a case label.
2531 Labels should only start a new basic block if their previous statement
2532 wasn't a label. Otherwise, sequence of labels would generate
2533 unnecessary basic blocks that only contain a single label. */
2536 stmt_starts_bb_p (tree t
, tree prev_t
)
2541 /* LABEL_EXPRs start a new basic block only if the preceding
2542 statement wasn't a label of the same type. This prevents the
2543 creation of consecutive blocks that have nothing but a single
2545 if (TREE_CODE (t
) == LABEL_EXPR
)
2547 /* Nonlocal and computed GOTO targets always start a new block. */
2548 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2549 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2552 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2554 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2557 cfg_stats
.num_merged_labels
++;
2568 /* Return true if T should end a basic block. */
2571 stmt_ends_bb_p (tree t
)
2573 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2577 /* Add gotos that used to be represented implicitly in the CFG. */
2580 disband_implicit_edges (void)
2583 block_stmt_iterator last
;
2590 last
= bsi_last (bb
);
2591 stmt
= last_stmt (bb
);
2593 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2595 /* Remove superfluous gotos from COND_EXPR branches. Moved
2596 from cfg_remove_useless_stmts here since it violates the
2597 invariants for tree--cfg correspondence and thus fits better
2598 here where we do it anyway. */
2599 e
= find_edge (bb
, bb
->next_bb
);
2602 if (e
->flags
& EDGE_TRUE_VALUE
)
2603 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2604 else if (e
->flags
& EDGE_FALSE_VALUE
)
2605 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2608 e
->flags
|= EDGE_FALLTHRU
;
2614 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2616 /* Remove the RETURN_EXPR if we may fall though to the exit
2618 gcc_assert (single_succ_p (bb
));
2619 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2621 if (bb
->next_bb
== EXIT_BLOCK_PTR
2622 && !TREE_OPERAND (stmt
, 0))
2624 bsi_remove (&last
, true);
2625 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2630 /* There can be no fallthru edge if the last statement is a control
2632 if (stmt
&& is_ctrl_stmt (stmt
))
2635 /* Find a fallthru edge and emit the goto if necessary. */
2636 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2637 if (e
->flags
& EDGE_FALLTHRU
)
2640 if (!e
|| e
->dest
== bb
->next_bb
)
2643 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2644 label
= tree_block_label (e
->dest
);
2646 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2647 #ifdef USE_MAPPED_LOCATION
2648 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2650 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2652 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2653 e
->flags
&= ~EDGE_FALLTHRU
;
2657 /* Remove block annotations and other datastructures. */
2660 delete_tree_cfg_annotations (void)
2662 label_to_block_map
= NULL
;
2666 /* Return the first statement in basic block BB. */
2669 first_stmt (basic_block bb
)
2671 block_stmt_iterator i
= bsi_start (bb
);
2672 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2676 /* Return the last statement in basic block BB. */
2679 last_stmt (basic_block bb
)
2681 block_stmt_iterator b
= bsi_last (bb
);
2682 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2686 /* Return a pointer to the last statement in block BB. */
2689 last_stmt_ptr (basic_block bb
)
2691 block_stmt_iterator last
= bsi_last (bb
);
2692 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2696 /* Return the last statement of an otherwise empty block. Return NULL
2697 if the block is totally empty, or if it contains more than one
2701 last_and_only_stmt (basic_block bb
)
2703 block_stmt_iterator i
= bsi_last (bb
);
2709 last
= bsi_stmt (i
);
2714 /* Empty statements should no longer appear in the instruction stream.
2715 Everything that might have appeared before should be deleted by
2716 remove_useless_stmts, and the optimizers should just bsi_remove
2717 instead of smashing with build_empty_stmt.
2719 Thus the only thing that should appear here in a block containing
2720 one executable statement is a label. */
2721 prev
= bsi_stmt (i
);
2722 if (TREE_CODE (prev
) == LABEL_EXPR
)
2729 /* Mark BB as the basic block holding statement T. */
2732 set_bb_for_stmt (tree t
, basic_block bb
)
2734 if (TREE_CODE (t
) == PHI_NODE
)
2736 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2738 tree_stmt_iterator i
;
2739 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2740 set_bb_for_stmt (tsi_stmt (i
), bb
);
2744 stmt_ann_t ann
= get_stmt_ann (t
);
2747 /* If the statement is a label, add the label to block-to-labels map
2748 so that we can speed up edge creation for GOTO_EXPRs. */
2749 if (TREE_CODE (t
) == LABEL_EXPR
)
2753 t
= LABEL_EXPR_LABEL (t
);
2754 uid
= LABEL_DECL_UID (t
);
2757 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2758 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2759 if (old_len
<= (unsigned) uid
)
2762 unsigned new_len
= 3 * uid
/ 2;
2764 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2766 addr
= VEC_address (basic_block
, label_to_block_map
);
2767 memset (&addr
[old_len
],
2768 0, sizeof (basic_block
) * (new_len
- old_len
));
2772 /* We're moving an existing label. Make sure that we've
2773 removed it from the old block. */
2775 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2776 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2781 /* Finds iterator for STMT. */
2783 extern block_stmt_iterator
2784 bsi_for_stmt (tree stmt
)
2786 block_stmt_iterator bsi
;
2788 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2789 if (bsi_stmt (bsi
) == stmt
)
2795 /* Mark statement T as modified, and update it. */
2797 update_modified_stmts (tree t
)
2799 if (TREE_CODE (t
) == STATEMENT_LIST
)
2801 tree_stmt_iterator i
;
2803 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2805 stmt
= tsi_stmt (i
);
2806 update_stmt_if_modified (stmt
);
2810 update_stmt_if_modified (t
);
2813 /* Insert statement (or statement list) T before the statement
2814 pointed-to by iterator I. M specifies how to update iterator I
2815 after insertion (see enum bsi_iterator_update). */
2818 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2820 set_bb_for_stmt (t
, i
->bb
);
2821 update_modified_stmts (t
);
2822 tsi_link_before (&i
->tsi
, t
, m
);
2826 /* Insert statement (or statement list) T after the statement
2827 pointed-to by iterator I. M specifies how to update iterator I
2828 after insertion (see enum bsi_iterator_update). */
2831 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2833 set_bb_for_stmt (t
, i
->bb
);
2834 update_modified_stmts (t
);
2835 tsi_link_after (&i
->tsi
, t
, m
);
2839 /* Remove the statement pointed to by iterator I. The iterator is updated
2840 to the next statement.
2842 When REMOVE_EH_INFO is true we remove the statement pointed to by
2843 iterator I from the EH tables. Otherwise we do not modify the EH
2846 Generally, REMOVE_EH_INFO should be true when the statement is going to
2847 be removed from the IL and not reinserted elsewhere. */
2850 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2852 tree t
= bsi_stmt (*i
);
2853 set_bb_for_stmt (t
, NULL
);
2854 delink_stmt_imm_use (t
);
2855 tsi_delink (&i
->tsi
);
2856 mark_stmt_modified (t
);
2858 remove_stmt_from_eh_region (t
);
2862 /* Move the statement at FROM so it comes right after the statement at TO. */
2865 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2867 tree stmt
= bsi_stmt (*from
);
2868 bsi_remove (from
, false);
2869 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2873 /* Move the statement at FROM so it comes right before the statement at TO. */
2876 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2878 tree stmt
= bsi_stmt (*from
);
2879 bsi_remove (from
, false);
2880 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2884 /* Move the statement at FROM to the end of basic block BB. */
2887 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2889 block_stmt_iterator last
= bsi_last (bb
);
2891 /* Have to check bsi_end_p because it could be an empty block. */
2892 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2893 bsi_move_before (from
, &last
);
2895 bsi_move_after (from
, &last
);
2899 /* Replace the contents of the statement pointed to by iterator BSI
2900 with STMT. If UPDATE_EH_INFO is true, the exception handling
2901 information of the original statement is moved to the new statement. */
2905 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2908 tree orig_stmt
= bsi_stmt (*bsi
);
2910 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2911 set_bb_for_stmt (stmt
, bsi
->bb
);
2913 /* Preserve EH region information from the original statement, if
2914 requested by the caller. */
2917 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2920 remove_stmt_from_eh_region (orig_stmt
);
2921 add_stmt_to_eh_region (stmt
, eh_region
);
2925 delink_stmt_imm_use (orig_stmt
);
2926 *bsi_stmt_ptr (*bsi
) = stmt
;
2927 mark_stmt_modified (stmt
);
2928 update_modified_stmts (stmt
);
2932 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2933 is made to place the statement in an existing basic block, but
2934 sometimes that isn't possible. When it isn't possible, the edge is
2935 split and the statement is added to the new block.
2937 In all cases, the returned *BSI points to the correct location. The
2938 return value is true if insertion should be done after the location,
2939 or false if it should be done before the location. If new basic block
2940 has to be created, it is stored in *NEW_BB. */
2943 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2944 basic_block
*new_bb
)
2946 basic_block dest
, src
;
2952 /* If the destination has one predecessor which has no PHI nodes,
2953 insert there. Except for the exit block.
2955 The requirement for no PHI nodes could be relaxed. Basically we
2956 would have to examine the PHIs to prove that none of them used
2957 the value set by the statement we want to insert on E. That
2958 hardly seems worth the effort. */
2959 if (single_pred_p (dest
)
2960 && ! phi_nodes (dest
)
2961 && dest
!= EXIT_BLOCK_PTR
)
2963 *bsi
= bsi_start (dest
);
2964 if (bsi_end_p (*bsi
))
2967 /* Make sure we insert after any leading labels. */
2968 tmp
= bsi_stmt (*bsi
);
2969 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2972 if (bsi_end_p (*bsi
))
2974 tmp
= bsi_stmt (*bsi
);
2977 if (bsi_end_p (*bsi
))
2979 *bsi
= bsi_last (dest
);
2986 /* If the source has one successor, the edge is not abnormal and
2987 the last statement does not end a basic block, insert there.
2988 Except for the entry block. */
2990 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2991 && single_succ_p (src
)
2992 && src
!= ENTRY_BLOCK_PTR
)
2994 *bsi
= bsi_last (src
);
2995 if (bsi_end_p (*bsi
))
2998 tmp
= bsi_stmt (*bsi
);
2999 if (!stmt_ends_bb_p (tmp
))
3002 /* Insert code just before returning the value. We may need to decompose
3003 the return in the case it contains non-trivial operand. */
3004 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3006 tree op
= TREE_OPERAND (tmp
, 0);
3007 if (op
&& !is_gimple_val (op
))
3009 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3010 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3011 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3018 /* Otherwise, create a new basic block, and split this edge. */
3019 dest
= split_edge (e
);
3022 e
= single_pred_edge (dest
);
3027 /* This routine will commit all pending edge insertions, creating any new
3028 basic blocks which are necessary. */
3031 bsi_commit_edge_inserts (void)
3037 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3040 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3041 bsi_commit_one_edge_insert (e
, NULL
);
3045 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3046 to this block, otherwise set it to NULL. */
3049 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3053 if (PENDING_STMT (e
))
3055 block_stmt_iterator bsi
;
3056 tree stmt
= PENDING_STMT (e
);
3058 PENDING_STMT (e
) = NULL_TREE
;
3060 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3061 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3063 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3068 /* Add STMT to the pending list of edge E. No actual insertion is
3069 made until a call to bsi_commit_edge_inserts () is made. */
3072 bsi_insert_on_edge (edge e
, tree stmt
)
3074 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3077 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3078 block has to be created, it is returned. */
3081 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3083 block_stmt_iterator bsi
;
3084 basic_block new_bb
= NULL
;
3086 gcc_assert (!PENDING_STMT (e
));
3088 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3089 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3091 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3096 /*---------------------------------------------------------------------------
3097 Tree specific functions for CFG manipulation
3098 ---------------------------------------------------------------------------*/
3100 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3103 reinstall_phi_args (edge new_edge
, edge old_edge
)
3107 if (!PENDING_STMT (old_edge
))
3110 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3112 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3114 tree result
= TREE_PURPOSE (var
);
3115 tree arg
= TREE_VALUE (var
);
3117 gcc_assert (result
== PHI_RESULT (phi
));
3119 add_phi_arg (phi
, arg
, new_edge
);
3122 PENDING_STMT (old_edge
) = NULL
;
3125 /* Returns the basic block after that the new basic block created
3126 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3127 near its "logical" location. This is of most help to humans looking
3128 at debugging dumps. */
3131 split_edge_bb_loc (edge edge_in
)
3133 basic_block dest
= edge_in
->dest
;
3135 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3136 return edge_in
->src
;
3138 return dest
->prev_bb
;
3141 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3142 Abort on abnormal edges. */
3145 tree_split_edge (edge edge_in
)
3147 basic_block new_bb
, after_bb
, dest
, src
;
3150 /* Abnormal edges cannot be split. */
3151 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3154 dest
= edge_in
->dest
;
3156 after_bb
= split_edge_bb_loc (edge_in
);
3158 new_bb
= create_empty_bb (after_bb
);
3159 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3160 new_bb
->count
= edge_in
->count
;
3161 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3162 new_edge
->probability
= REG_BR_PROB_BASE
;
3163 new_edge
->count
= edge_in
->count
;
3165 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3167 reinstall_phi_args (new_edge
, e
);
3173 /* Return true when BB has label LABEL in it. */
3176 has_label_p (basic_block bb
, tree label
)
3178 block_stmt_iterator bsi
;
3180 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3182 tree stmt
= bsi_stmt (bsi
);
3184 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3186 if (LABEL_EXPR_LABEL (stmt
) == label
)
3193 /* Callback for walk_tree, check that all elements with address taken are
3194 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3195 inside a PHI node. */
3198 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3201 bool in_phi
= (data
!= NULL
);
3206 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3207 #define CHECK_OP(N, MSG) \
3208 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3209 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3211 switch (TREE_CODE (t
))
3214 if (SSA_NAME_IN_FREE_LIST (t
))
3216 error ("SSA name in freelist but still referenced");
3222 x
= fold (ASSERT_EXPR_COND (t
));
3223 if (x
== boolean_false_node
)
3225 error ("ASSERT_EXPR with an always-false condition");
3231 x
= TREE_OPERAND (t
, 0);
3232 if (TREE_CODE (x
) == BIT_FIELD_REF
3233 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3235 error ("GIMPLE register modified with BIT_FIELD_REF");
3244 bool old_side_effects
;
3247 bool new_side_effects
;
3249 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3250 dead PHIs that take the address of something. But if the PHI
3251 result is dead, the fact that it takes the address of anything
3252 is irrelevant. Because we can not tell from here if a PHI result
3253 is dead, we just skip this check for PHIs altogether. This means
3254 we may be missing "valid" checks, but what can you do?
3255 This was PR19217. */
3259 old_invariant
= TREE_INVARIANT (t
);
3260 old_constant
= TREE_CONSTANT (t
);
3261 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3263 recompute_tree_invariant_for_addr_expr (t
);
3264 new_invariant
= TREE_INVARIANT (t
);
3265 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3266 new_constant
= TREE_CONSTANT (t
);
3268 if (old_invariant
!= new_invariant
)
3270 error ("invariant not recomputed when ADDR_EXPR changed");
3274 if (old_constant
!= new_constant
)
3276 error ("constant not recomputed when ADDR_EXPR changed");
3279 if (old_side_effects
!= new_side_effects
)
3281 error ("side effects not recomputed when ADDR_EXPR changed");
3285 /* Skip any references (they will be checked when we recurse down the
3286 tree) and ensure that any variable used as a prefix is marked
3288 for (x
= TREE_OPERAND (t
, 0);
3289 handled_component_p (x
);
3290 x
= TREE_OPERAND (x
, 0))
3293 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3295 if (!TREE_ADDRESSABLE (x
))
3297 error ("address taken, but ADDRESSABLE bit not set");
3304 x
= COND_EXPR_COND (t
);
3305 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3307 error ("non-boolean used in condition");
3310 if (!is_gimple_condexpr (x
))
3312 error ("invalid conditional operand");
3319 case FIX_TRUNC_EXPR
:
3321 case FIX_FLOOR_EXPR
:
3322 case FIX_ROUND_EXPR
:
3327 case NON_LVALUE_EXPR
:
3328 case TRUTH_NOT_EXPR
:
3329 CHECK_OP (0, "invalid operand to unary operator");
3336 case ARRAY_RANGE_REF
:
3338 case VIEW_CONVERT_EXPR
:
3339 /* We have a nest of references. Verify that each of the operands
3340 that determine where to reference is either a constant or a variable,
3341 verify that the base is valid, and then show we've already checked
3343 while (handled_component_p (t
))
3345 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3346 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3347 else if (TREE_CODE (t
) == ARRAY_REF
3348 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3350 CHECK_OP (1, "invalid array index");
3351 if (TREE_OPERAND (t
, 2))
3352 CHECK_OP (2, "invalid array lower bound");
3353 if (TREE_OPERAND (t
, 3))
3354 CHECK_OP (3, "invalid array stride");
3356 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3358 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3359 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3362 t
= TREE_OPERAND (t
, 0);
3365 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3367 error ("invalid reference prefix");
3379 case UNORDERED_EXPR
:
3390 case TRUNC_DIV_EXPR
:
3392 case FLOOR_DIV_EXPR
:
3393 case ROUND_DIV_EXPR
:
3394 case TRUNC_MOD_EXPR
:
3396 case FLOOR_MOD_EXPR
:
3397 case ROUND_MOD_EXPR
:
3399 case EXACT_DIV_EXPR
:
3409 CHECK_OP (0, "invalid operand to binary operator");
3410 CHECK_OP (1, "invalid operand to binary operator");
3422 /* Verify STMT, return true if STMT is not in GIMPLE form.
3423 TODO: Implement type checking. */
3426 verify_stmt (tree stmt
, bool last_in_block
)
3430 if (OMP_DIRECTIVE_P (stmt
))
3432 /* OpenMP directives are validated by the FE and never operated
3433 on by the optimizers. Furthermore, OMP_FOR may contain
3434 non-gimple expressions when the main index variable has had
3435 its address taken. This does not affect the loop itself
3436 because the header of an OMP_FOR is merely used to determine
3437 how to setup the parallel iteration. */
3441 if (!is_gimple_stmt (stmt
))
3443 error ("is not a valid GIMPLE statement");
3447 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3450 debug_generic_stmt (addr
);
3454 /* If the statement is marked as part of an EH region, then it is
3455 expected that the statement could throw. Verify that when we
3456 have optimizations that simplify statements such that we prove
3457 that they cannot throw, that we update other data structures
3459 if (lookup_stmt_eh_region (stmt
) >= 0)
3461 if (!tree_could_throw_p (stmt
))
3463 error ("statement marked for throw, but doesn%'t");
3466 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3468 error ("statement marked for throw in middle of block");
3476 debug_generic_stmt (stmt
);
3481 /* Return true when the T can be shared. */
3484 tree_node_can_be_shared (tree t
)
3486 if (IS_TYPE_OR_DECL_P (t
)
3487 || is_gimple_min_invariant (t
)
3488 || TREE_CODE (t
) == SSA_NAME
3489 || t
== error_mark_node
3490 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3493 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3496 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3497 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3498 || TREE_CODE (t
) == COMPONENT_REF
3499 || TREE_CODE (t
) == REALPART_EXPR
3500 || TREE_CODE (t
) == IMAGPART_EXPR
)
3501 t
= TREE_OPERAND (t
, 0);
3510 /* Called via walk_trees. Verify tree sharing. */
3513 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3515 htab_t htab
= (htab_t
) data
;
3518 if (tree_node_can_be_shared (*tp
))
3520 *walk_subtrees
= false;
3524 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3526 return (tree
) *slot
;
3533 /* Verify the GIMPLE statement chain. */
3539 block_stmt_iterator bsi
;
3544 timevar_push (TV_TREE_STMT_VERIFY
);
3545 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3552 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3554 int phi_num_args
= PHI_NUM_ARGS (phi
);
3556 if (bb_for_stmt (phi
) != bb
)
3558 error ("bb_for_stmt (phi) is set to a wrong basic block");
3562 for (i
= 0; i
< phi_num_args
; i
++)
3564 tree t
= PHI_ARG_DEF (phi
, i
);
3567 /* Addressable variables do have SSA_NAMEs but they
3568 are not considered gimple values. */
3569 if (TREE_CODE (t
) != SSA_NAME
3570 && TREE_CODE (t
) != FUNCTION_DECL
3571 && !is_gimple_val (t
))
3573 error ("PHI def is not a GIMPLE value");
3574 debug_generic_stmt (phi
);
3575 debug_generic_stmt (t
);
3579 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3582 debug_generic_stmt (addr
);
3586 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3589 error ("incorrect sharing of tree nodes");
3590 debug_generic_stmt (phi
);
3591 debug_generic_stmt (addr
);
3597 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3599 tree stmt
= bsi_stmt (bsi
);
3601 if (bb_for_stmt (stmt
) != bb
)
3603 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3608 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3609 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3612 error ("incorrect sharing of tree nodes");
3613 debug_generic_stmt (stmt
);
3614 debug_generic_stmt (addr
);
3621 internal_error ("verify_stmts failed");
3624 timevar_pop (TV_TREE_STMT_VERIFY
);
3628 /* Verifies that the flow information is OK. */
3631 tree_verify_flow_info (void)
3635 block_stmt_iterator bsi
;
3640 if (ENTRY_BLOCK_PTR
->stmt_list
)
3642 error ("ENTRY_BLOCK has a statement list associated with it");
3646 if (EXIT_BLOCK_PTR
->stmt_list
)
3648 error ("EXIT_BLOCK has a statement list associated with it");
3652 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3653 if (e
->flags
& EDGE_FALLTHRU
)
3655 error ("fallthru to exit from bb %d", e
->src
->index
);
3661 bool found_ctrl_stmt
= false;
3665 /* Skip labels on the start of basic block. */
3666 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3668 tree prev_stmt
= stmt
;
3670 stmt
= bsi_stmt (bsi
);
3672 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3675 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3677 error ("nonlocal label ");
3678 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3679 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3684 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3687 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3688 fprintf (stderr
, " to block does not match in bb %d",
3693 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3694 != current_function_decl
)
3697 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3698 fprintf (stderr
, " has incorrect context in bb %d",
3704 /* Verify that body of basic block BB is free of control flow. */
3705 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3707 tree stmt
= bsi_stmt (bsi
);
3709 if (found_ctrl_stmt
)
3711 error ("control flow in the middle of basic block %d",
3716 if (stmt_ends_bb_p (stmt
))
3717 found_ctrl_stmt
= true;
3719 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3722 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3723 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3728 bsi
= bsi_last (bb
);
3729 if (bsi_end_p (bsi
))
3732 stmt
= bsi_stmt (bsi
);
3734 err
|= verify_eh_edges (stmt
);
3736 if (is_ctrl_stmt (stmt
))
3738 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3739 if (e
->flags
& EDGE_FALLTHRU
)
3741 error ("fallthru edge after a control statement in bb %d",
3747 switch (TREE_CODE (stmt
))
3753 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3754 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3756 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3760 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3762 if (!true_edge
|| !false_edge
3763 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3764 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3765 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3766 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3767 || EDGE_COUNT (bb
->succs
) >= 3)
3769 error ("wrong outgoing edge flags at end of bb %d",
3774 if (!has_label_p (true_edge
->dest
,
3775 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3777 error ("%<then%> label does not match edge at end of bb %d",
3782 if (!has_label_p (false_edge
->dest
,
3783 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3785 error ("%<else%> label does not match edge at end of bb %d",
3793 if (simple_goto_p (stmt
))
3795 error ("explicit goto at end of bb %d", bb
->index
);
3800 /* FIXME. We should double check that the labels in the
3801 destination blocks have their address taken. */
3802 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3803 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3804 | EDGE_FALSE_VALUE
))
3805 || !(e
->flags
& EDGE_ABNORMAL
))
3807 error ("wrong outgoing edge flags at end of bb %d",
3815 if (!single_succ_p (bb
)
3816 || (single_succ_edge (bb
)->flags
3817 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3818 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3820 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3823 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3825 error ("return edge does not point to exit in bb %d",
3838 vec
= SWITCH_LABELS (stmt
);
3839 n
= TREE_VEC_LENGTH (vec
);
3841 /* Mark all the destination basic blocks. */
3842 for (i
= 0; i
< n
; ++i
)
3844 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3845 basic_block label_bb
= label_to_block (lab
);
3847 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3848 label_bb
->aux
= (void *)1;
3851 /* Verify that the case labels are sorted. */
3852 prev
= TREE_VEC_ELT (vec
, 0);
3853 for (i
= 1; i
< n
- 1; ++i
)
3855 tree c
= TREE_VEC_ELT (vec
, i
);
3858 error ("found default case not at end of case vector");
3862 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3864 error ("case labels not sorted: ");
3865 print_generic_expr (stderr
, prev
, 0);
3866 fprintf (stderr
," is greater than ");
3867 print_generic_expr (stderr
, c
, 0);
3868 fprintf (stderr
," but comes before it.\n");
3873 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3875 error ("no default case found at end of case vector");
3879 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3883 error ("extra outgoing edge %d->%d",
3884 bb
->index
, e
->dest
->index
);
3887 e
->dest
->aux
= (void *)2;
3888 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3889 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3891 error ("wrong outgoing edge flags at end of bb %d",
3897 /* Check that we have all of them. */
3898 for (i
= 0; i
< n
; ++i
)
3900 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3901 basic_block label_bb
= label_to_block (lab
);
3903 if (label_bb
->aux
!= (void *)2)
3905 error ("missing edge %i->%i",
3906 bb
->index
, label_bb
->index
);
3911 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3912 e
->dest
->aux
= (void *)0;
3919 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3920 verify_dominators (CDI_DOMINATORS
);
3926 /* Updates phi nodes after creating a forwarder block joined
3927 by edge FALLTHRU. */
3930 tree_make_forwarder_block (edge fallthru
)
3934 basic_block dummy
, bb
;
3935 tree phi
, new_phi
, var
;
3937 dummy
= fallthru
->src
;
3938 bb
= fallthru
->dest
;
3940 if (single_pred_p (bb
))
3943 /* If we redirected a branch we must create new phi nodes at the
3945 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3947 var
= PHI_RESULT (phi
);
3948 new_phi
= create_phi_node (var
, bb
);
3949 SSA_NAME_DEF_STMT (var
) = new_phi
;
3950 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3951 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3954 /* Ensure that the PHI node chain is in the same order. */
3955 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3957 /* Add the arguments we have stored on edges. */
3958 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3963 flush_pending_stmts (e
);
3968 /* Return a non-special label in the head of basic block BLOCK.
3969 Create one if it doesn't exist. */
3972 tree_block_label (basic_block bb
)
3974 block_stmt_iterator i
, s
= bsi_start (bb
);
3978 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3980 stmt
= bsi_stmt (i
);
3981 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3983 label
= LABEL_EXPR_LABEL (stmt
);
3984 if (!DECL_NONLOCAL (label
))
3987 bsi_move_before (&i
, &s
);
3992 label
= create_artificial_label ();
3993 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3994 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3999 /* Attempt to perform edge redirection by replacing a possibly complex
4000 jump instruction by a goto or by removing the jump completely.
4001 This can apply only if all edges now point to the same block. The
4002 parameters and return values are equivalent to
4003 redirect_edge_and_branch. */
4006 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4008 basic_block src
= e
->src
;
4009 block_stmt_iterator b
;
4012 /* We can replace or remove a complex jump only when we have exactly
4014 if (EDGE_COUNT (src
->succs
) != 2
4015 /* Verify that all targets will be TARGET. Specifically, the
4016 edge that is not E must also go to TARGET. */
4017 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4023 stmt
= bsi_stmt (b
);
4025 if (TREE_CODE (stmt
) == COND_EXPR
4026 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4028 bsi_remove (&b
, true);
4029 e
= ssa_redirect_edge (e
, target
);
4030 e
->flags
= EDGE_FALLTHRU
;
4038 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4039 edge representing the redirected branch. */
4042 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4044 basic_block bb
= e
->src
;
4045 block_stmt_iterator bsi
;
4049 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4052 if (e
->src
!= ENTRY_BLOCK_PTR
4053 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4056 if (e
->dest
== dest
)
4059 label
= tree_block_label (dest
);
4061 bsi
= bsi_last (bb
);
4062 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4064 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4067 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4068 ? COND_EXPR_THEN (stmt
)
4069 : COND_EXPR_ELSE (stmt
));
4070 GOTO_DESTINATION (stmt
) = label
;
4074 /* No non-abnormal edges should lead from a non-simple goto, and
4075 simple ones should be represented implicitly. */
4080 tree cases
= get_cases_for_edge (e
, stmt
);
4082 /* If we have a list of cases associated with E, then use it
4083 as it's a lot faster than walking the entire case vector. */
4086 edge e2
= find_edge (e
->src
, dest
);
4093 CASE_LABEL (cases
) = label
;
4094 cases
= TREE_CHAIN (cases
);
4097 /* If there was already an edge in the CFG, then we need
4098 to move all the cases associated with E to E2. */
4101 tree cases2
= get_cases_for_edge (e2
, stmt
);
4103 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4104 TREE_CHAIN (cases2
) = first
;
4109 tree vec
= SWITCH_LABELS (stmt
);
4110 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4112 for (i
= 0; i
< n
; i
++)
4114 tree elt
= TREE_VEC_ELT (vec
, i
);
4116 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4117 CASE_LABEL (elt
) = label
;
4125 bsi_remove (&bsi
, true);
4126 e
->flags
|= EDGE_FALLTHRU
;
4130 /* Otherwise it must be a fallthru edge, and we don't need to
4131 do anything besides redirecting it. */
4132 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4136 /* Update/insert PHI nodes as necessary. */
4138 /* Now update the edges in the CFG. */
4139 e
= ssa_redirect_edge (e
, dest
);
4145 /* Simple wrapper, as we can always redirect fallthru edges. */
4148 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4150 e
= tree_redirect_edge_and_branch (e
, dest
);
4157 /* Splits basic block BB after statement STMT (but at least after the
4158 labels). If STMT is NULL, BB is split just after the labels. */
4161 tree_split_block (basic_block bb
, void *stmt
)
4163 block_stmt_iterator bsi
, bsi_tgt
;
4169 new_bb
= create_empty_bb (bb
);
4171 /* Redirect the outgoing edges. */
4172 new_bb
->succs
= bb
->succs
;
4174 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4177 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4180 /* Move everything from BSI to the new basic block. */
4181 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4183 act
= bsi_stmt (bsi
);
4184 if (TREE_CODE (act
) == LABEL_EXPR
)
4197 bsi_tgt
= bsi_start (new_bb
);
4198 while (!bsi_end_p (bsi
))
4200 act
= bsi_stmt (bsi
);
4201 bsi_remove (&bsi
, false);
4202 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4209 /* Moves basic block BB after block AFTER. */
4212 tree_move_block_after (basic_block bb
, basic_block after
)
4214 if (bb
->prev_bb
== after
)
4218 link_block (bb
, after
);
4224 /* Return true if basic_block can be duplicated. */
4227 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4233 /* Create a duplicate of the basic block BB. NOTE: This does not
4234 preserve SSA form. */
4237 tree_duplicate_bb (basic_block bb
)
4240 block_stmt_iterator bsi
, bsi_tgt
;
4243 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4245 /* Copy the PHI nodes. We ignore PHI node arguments here because
4246 the incoming edges have not been setup yet. */
4247 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4249 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4250 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4253 /* Keep the chain of PHI nodes in the same order so that they can be
4254 updated by ssa_redirect_edge. */
4255 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4257 bsi_tgt
= bsi_start (new_bb
);
4258 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4260 def_operand_p def_p
;
4261 ssa_op_iter op_iter
;
4265 stmt
= bsi_stmt (bsi
);
4266 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4269 /* Create a new copy of STMT and duplicate STMT's virtual
4271 copy
= unshare_expr (stmt
);
4272 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4273 copy_virtual_operands (copy
, stmt
);
4274 region
= lookup_stmt_eh_region (stmt
);
4276 add_stmt_to_eh_region (copy
, region
);
4278 /* Create new names for all the definitions created by COPY and
4279 add replacement mappings for each new name. */
4280 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4281 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4288 /* Basic block BB_COPY was created by code duplication. Add phi node
4289 arguments for edges going out of BB_COPY. The blocks that were
4290 duplicated have BB_DUPLICATED set. */
4293 add_phi_args_after_copy_bb (basic_block bb_copy
)
4295 basic_block bb
, dest
;
4298 tree phi
, phi_copy
, phi_next
, def
;
4300 bb
= get_bb_original (bb_copy
);
4302 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4304 if (!phi_nodes (e_copy
->dest
))
4307 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4308 dest
= get_bb_original (e_copy
->dest
);
4310 dest
= e_copy
->dest
;
4312 e
= find_edge (bb
, dest
);
4315 /* During loop unrolling the target of the latch edge is copied.
4316 In this case we are not looking for edge to dest, but to
4317 duplicated block whose original was dest. */
4318 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4319 if ((e
->dest
->flags
& BB_DUPLICATED
)
4320 && get_bb_original (e
->dest
) == dest
)
4323 gcc_assert (e
!= NULL
);
4326 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4328 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4330 phi_next
= PHI_CHAIN (phi
);
4331 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4332 add_phi_arg (phi_copy
, def
, e_copy
);
4337 /* Blocks in REGION_COPY array of length N_REGION were created by
4338 duplication of basic blocks. Add phi node arguments for edges
4339 going from these blocks. */
4342 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4346 for (i
= 0; i
< n_region
; i
++)
4347 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4349 for (i
= 0; i
< n_region
; i
++)
4350 add_phi_args_after_copy_bb (region_copy
[i
]);
4352 for (i
= 0; i
< n_region
; i
++)
4353 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4356 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4357 important exit edge EXIT. By important we mean that no SSA name defined
4358 inside region is live over the other exit edges of the region. All entry
4359 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4360 to the duplicate of the region. SSA form, dominance and loop information
4361 is updated. The new basic blocks are stored to REGION_COPY in the same
4362 order as they had in REGION, provided that REGION_COPY is not NULL.
4363 The function returns false if it is unable to copy the region,
4367 tree_duplicate_sese_region (edge entry
, edge exit
,
4368 basic_block
*region
, unsigned n_region
,
4369 basic_block
*region_copy
)
4372 bool free_region_copy
= false, copying_header
= false;
4373 struct loop
*loop
= entry
->dest
->loop_father
;
4377 int total_freq
= 0, entry_freq
= 0;
4378 gcov_type total_count
= 0, entry_count
= 0;
4380 if (!can_copy_bbs_p (region
, n_region
))
4383 /* Some sanity checking. Note that we do not check for all possible
4384 missuses of the functions. I.e. if you ask to copy something weird,
4385 it will work, but the state of structures probably will not be
4387 for (i
= 0; i
< n_region
; i
++)
4389 /* We do not handle subloops, i.e. all the blocks must belong to the
4391 if (region
[i
]->loop_father
!= loop
)
4394 if (region
[i
] != entry
->dest
4395 && region
[i
] == loop
->header
)
4401 /* In case the function is used for loop header copying (which is the primary
4402 use), ensure that EXIT and its copy will be new latch and entry edges. */
4403 if (loop
->header
== entry
->dest
)
4405 copying_header
= true;
4406 loop
->copy
= loop
->outer
;
4408 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4411 for (i
= 0; i
< n_region
; i
++)
4412 if (region
[i
] != exit
->src
4413 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4419 region_copy
= XNEWVEC (basic_block
, n_region
);
4420 free_region_copy
= true;
4423 gcc_assert (!need_ssa_update_p ());
4425 /* Record blocks outside the region that are dominated by something
4427 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4428 initialize_original_copy_tables ();
4430 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4432 if (entry
->dest
->count
)
4434 total_count
= entry
->dest
->count
;
4435 entry_count
= entry
->count
;
4436 /* Fix up corner cases, to avoid division by zero or creation of negative
4438 if (entry_count
> total_count
)
4439 entry_count
= total_count
;
4443 total_freq
= entry
->dest
->frequency
;
4444 entry_freq
= EDGE_FREQUENCY (entry
);
4445 /* Fix up corner cases, to avoid division by zero or creation of negative
4447 if (total_freq
== 0)
4449 else if (entry_freq
> total_freq
)
4450 entry_freq
= total_freq
;
4453 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4454 split_edge_bb_loc (entry
));
4457 scale_bbs_frequencies_gcov_type (region
, n_region
,
4458 total_count
- entry_count
,
4460 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4465 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4467 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4472 loop
->header
= exit
->dest
;
4473 loop
->latch
= exit
->src
;
4476 /* Redirect the entry and add the phi node arguments. */
4477 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4478 gcc_assert (redirected
!= NULL
);
4479 flush_pending_stmts (entry
);
4481 /* Concerning updating of dominators: We must recount dominators
4482 for entry block and its copy. Anything that is outside of the
4483 region, but was dominated by something inside needs recounting as
4485 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4486 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4487 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4490 /* Add the other PHI node arguments. */
4491 add_phi_args_after_copy (region_copy
, n_region
);
4493 /* Update the SSA web. */
4494 update_ssa (TODO_update_ssa
);
4496 if (free_region_copy
)
4499 free_original_copy_tables ();
4504 DEF_VEC_P(basic_block);
4505 DEF_VEC_ALLOC_P(basic_block,heap);
4508 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4509 adding blocks when the dominator traversal reaches EXIT. This
4510 function silently assumes that ENTRY strictly dominates EXIT. */
4513 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4514 VEC(basic_block
,heap
) **bbs_p
)
4518 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4520 son
= next_dom_son (CDI_DOMINATORS
, son
))
4522 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4524 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4534 bitmap vars_to_remove
;
4535 htab_t new_label_map
;
4539 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4540 contained in *TP and change the DECL_CONTEXT of every local
4541 variable referenced in *TP. */
4544 move_stmt_r (tree
*tp
, int *walk_subtrees
, void *data
)
4546 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4549 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (t
))))
4550 TREE_BLOCK (t
) = p
->block
;
4552 if (OMP_DIRECTIVE_P (t
) && TREE_CODE (t
) != OMP_RETURN_EXPR
)
4554 /* Do not remap variables inside OMP directives. Variables
4555 referenced in clauses and directive header belong to the
4556 parent function and should not be moved into the child
4558 bool save_remap_decls_p
= p
->remap_decls_p
;
4559 p
->remap_decls_p
= false;
4562 walk_tree (&OMP_BODY (t
), move_stmt_r
, p
, NULL
);
4564 p
->remap_decls_p
= save_remap_decls_p
;
4566 else if (DECL_P (t
) && DECL_CONTEXT (t
) == p
->from_context
)
4568 if (TREE_CODE (t
) == LABEL_DECL
)
4570 if (p
->new_label_map
)
4572 struct tree_map in
, *out
;
4574 out
= htab_find_with_hash (p
->new_label_map
, &in
, DECL_UID (t
));
4579 DECL_CONTEXT (t
) = p
->to_context
;
4581 else if (p
->remap_decls_p
)
4583 DECL_CONTEXT (t
) = p
->to_context
;
4585 if (TREE_CODE (t
) == VAR_DECL
)
4587 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4588 f
->unexpanded_var_list
4589 = tree_cons (0, t
, f
->unexpanded_var_list
);
4591 /* Mark T to be removed from the original function,
4592 otherwise it will be given a DECL_RTL when the
4593 original function is expanded. */
4594 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (t
));
4598 else if (TYPE_P (t
))
4605 /* Move basic block BB from function CFUN to function DEST_FN. The
4606 block is moved out of the original linked list and placed after
4607 block AFTER in the new list. Also, the block is removed from the
4608 original array of blocks and placed in DEST_FN's array of blocks.
4609 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4610 updated to reflect the moved edges.
4612 On exit, local variables that need to be removed from
4613 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4616 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4617 basic_block after
, bool update_edge_count_p
,
4618 bitmap vars_to_remove
, htab_t new_label_map
, int eh_offset
)
4620 struct control_flow_graph
*cfg
;
4623 block_stmt_iterator si
;
4624 struct move_stmt_d d
;
4625 unsigned old_len
, new_len
;
4628 /* Link BB to the new linked list. */
4629 move_block_after (bb
, after
);
4631 /* Update the edge count in the corresponding flowgraphs. */
4632 if (update_edge_count_p
)
4633 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4635 cfun
->cfg
->x_n_edges
--;
4636 dest_cfun
->cfg
->x_n_edges
++;
4639 /* Remove BB from the original basic block array. */
4640 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4641 cfun
->cfg
->x_n_basic_blocks
--;
4643 /* Grow DEST_CFUN's basic block array if needed. */
4644 cfg
= dest_cfun
->cfg
;
4645 cfg
->x_n_basic_blocks
++;
4646 if (bb
->index
> cfg
->x_last_basic_block
)
4647 cfg
->x_last_basic_block
= bb
->index
;
4649 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4650 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4652 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4653 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4654 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4655 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4658 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4659 cfg
->x_last_basic_block
, bb
);
4661 /* The statements in BB need to be associated with a new TREE_BLOCK.
4662 Labels need to be associated with a new label-to-block map. */
4663 memset (&d
, 0, sizeof (d
));
4664 d
.vars_to_remove
= vars_to_remove
;
4666 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4668 tree stmt
= bsi_stmt (si
);
4671 d
.from_context
= cfun
->decl
;
4672 d
.to_context
= dest_cfun
->decl
;
4673 d
.remap_decls_p
= true;
4674 d
.new_label_map
= new_label_map
;
4675 if (TREE_BLOCK (stmt
))
4676 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4678 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4680 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4682 tree label
= LABEL_EXPR_LABEL (stmt
);
4683 int uid
= LABEL_DECL_UID (label
);
4685 gcc_assert (uid
> -1);
4687 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4688 if (old_len
<= (unsigned) uid
)
4690 new_len
= 3 * uid
/ 2;
4691 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4693 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4694 memset (&addr
[old_len
], 0,
4695 sizeof (basic_block
) * (new_len
- old_len
));
4698 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4699 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4701 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4703 if (uid
>= dest_cfun
->last_label_uid
)
4704 dest_cfun
->last_label_uid
= uid
+ 1;
4706 else if (TREE_CODE (stmt
) == RESX_EXPR
&& eh_offset
!= 0)
4707 TREE_OPERAND (stmt
, 0) =
4708 build_int_cst (NULL_TREE
,
4709 TREE_INT_CST_LOW (TREE_OPERAND (stmt
, 0))
4712 region
= lookup_stmt_eh_region (stmt
);
4715 add_stmt_to_eh_region_fn (dest_cfun
, stmt
, region
+ eh_offset
);
4716 remove_stmt_from_eh_region (stmt
);
4721 /* Examine the statements in BB (which is in SRC_CFUN); find and return
4722 the outermost EH region. Use REGION as the incoming base EH region. */
4725 find_outermost_region_in_block (struct function
*src_cfun
,
4726 basic_block bb
, int region
)
4728 block_stmt_iterator si
;
4730 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4732 tree stmt
= bsi_stmt (si
);
4735 stmt_region
= lookup_stmt_eh_region_fn (src_cfun
, stmt
);
4737 && (region
< 0 || eh_region_outer_p (src_cfun
, stmt_region
, region
)))
4738 region
= stmt_region
;
4745 new_label_mapper (tree decl
, void *data
)
4747 htab_t hash
= (htab_t
) data
;
4751 gcc_assert (TREE_CODE (decl
) == LABEL_DECL
);
4753 m
= xmalloc (sizeof (struct tree_map
));
4754 m
->hash
= DECL_UID (decl
);
4756 m
->to
= create_artificial_label ();
4757 LABEL_DECL_UID (m
->to
) = LABEL_DECL_UID (decl
);
4759 slot
= htab_find_slot_with_hash (hash
, m
, m
->hash
, INSERT
);
4760 gcc_assert (*slot
== NULL
);
4767 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4768 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4769 single basic block in the original CFG and the new basic block is
4770 returned. DEST_CFUN must not have a CFG yet.
4772 Note that the region need not be a pure SESE region. Blocks inside
4773 the region may contain calls to abort/exit. The only restriction
4774 is that ENTRY_BB should be the only entry point and it must
4777 All local variables referenced in the region are assumed to be in
4778 the corresponding BLOCK_VARS and unexpanded variable lists
4779 associated with DEST_CFUN. */
4782 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4783 basic_block exit_bb
)
4785 VEC(basic_block
,heap
) *bbs
;
4786 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4787 struct function
*saved_cfun
;
4788 int *entry_flag
, *exit_flag
, eh_offset
;
4789 unsigned i
, num_entry_edges
, num_exit_edges
;
4792 bitmap vars_to_remove
;
4793 htab_t new_label_map
;
4797 /* Collect all the blocks in the region. Manually add ENTRY_BB
4798 because it won't be added by dfs_enumerate_from. */
4799 calculate_dominance_info (CDI_DOMINATORS
);
4801 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4803 gcc_assert (entry_bb
!= exit_bb
4804 && dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
));
4807 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4808 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4810 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4811 the predecessor edges to ENTRY_BB and the successor edges to
4812 EXIT_BB so that we can re-attach them to the new basic block that
4813 will replace the region. */
4814 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4815 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4816 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4818 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4820 entry_flag
[i
] = e
->flags
;
4821 entry_pred
[i
++] = e
->src
;
4825 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4826 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
, sizeof (basic_block
));
4827 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4829 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4831 exit_flag
[i
] = e
->flags
;
4832 exit_succ
[i
++] = e
->dest
;
4836 /* Switch context to the child function to initialize DEST_FN's CFG. */
4837 gcc_assert (dest_cfun
->cfg
== NULL
);
4840 init_empty_tree_cfg ();
4842 /* Initialize EH information for the new function. */
4844 new_label_map
= NULL
;
4849 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4850 region
= find_outermost_region_in_block (saved_cfun
, bb
, region
);
4852 init_eh_for_function ();
4855 new_label_map
= htab_create (17, tree_map_hash
, tree_map_eq
, free
);
4856 eh_offset
= duplicate_eh_regions (saved_cfun
, new_label_mapper
,
4857 new_label_map
, region
, 0);
4863 /* Move blocks from BBS into DEST_CFUN. */
4864 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4865 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4866 vars_to_remove
= BITMAP_ALLOC (NULL
);
4867 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4869 /* No need to update edge counts on the last block. It has
4870 already been updated earlier when we detached the region from
4871 the original CFG. */
4872 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
,
4873 new_label_map
, eh_offset
);
4878 htab_delete (new_label_map
);
4880 /* Remove the variables marked in VARS_TO_REMOVE from
4881 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4882 DECL_RTL in the context of CFUN. */
4883 if (!bitmap_empty_p (vars_to_remove
))
4887 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4889 tree var
= TREE_VALUE (*p
);
4890 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4892 *p
= TREE_CHAIN (*p
);
4896 p
= &TREE_CHAIN (*p
);
4900 BITMAP_FREE (vars_to_remove
);
4902 /* Rewire the entry and exit blocks. The successor to the entry
4903 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4904 the child function. Similarly, the predecessor of DEST_FN's
4905 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4906 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4907 various CFG manipulation function get to the right CFG.
4909 FIXME, this is silly. The CFG ought to become a parameter to
4912 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4913 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4916 /* Back in the original function, the SESE region has disappeared,
4917 create a new basic block in its place. */
4918 bb
= create_empty_bb (entry_pred
[0]);
4919 for (i
= 0; i
< num_entry_edges
; i
++)
4920 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4922 for (i
= 0; i
< num_exit_edges
; i
++)
4923 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4929 free_dominance_info (CDI_DOMINATORS
);
4930 free_dominance_info (CDI_POST_DOMINATORS
);
4931 VEC_free (basic_block
, heap
, bbs
);
4937 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4940 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4942 tree arg
, vars
, var
;
4943 bool ignore_topmost_bind
= false, any_var
= false;
4946 struct function
*saved_cfun
;
4948 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4950 arg
= DECL_ARGUMENTS (fn
);
4953 print_generic_expr (file
, arg
, dump_flags
);
4954 if (TREE_CHAIN (arg
))
4955 fprintf (file
, ", ");
4956 arg
= TREE_CHAIN (arg
);
4958 fprintf (file
, ")\n");
4960 if (flags
& TDF_DETAILS
)
4961 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4962 if (flags
& TDF_RAW
)
4964 dump_node (fn
, TDF_SLIM
| flags
, file
);
4968 /* Switch CFUN to point to FN. */
4970 cfun
= DECL_STRUCT_FUNCTION (fn
);
4972 /* When GIMPLE is lowered, the variables are no longer available in
4973 BIND_EXPRs, so display them separately. */
4974 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4976 ignore_topmost_bind
= true;
4978 fprintf (file
, "{\n");
4979 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4981 var
= TREE_VALUE (vars
);
4983 print_generic_decl (file
, var
, flags
);
4984 fprintf (file
, "\n");
4990 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4992 /* Make a CFG based dump. */
4993 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4994 if (!ignore_topmost_bind
)
4995 fprintf (file
, "{\n");
4997 if (any_var
&& n_basic_blocks
)
4998 fprintf (file
, "\n");
5001 dump_generic_bb (file
, bb
, 2, flags
);
5003 fprintf (file
, "}\n");
5004 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5010 /* Make a tree based dump. */
5011 chain
= DECL_SAVED_TREE (fn
);
5013 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
5015 if (ignore_topmost_bind
)
5017 chain
= BIND_EXPR_BODY (chain
);
5025 if (!ignore_topmost_bind
)
5026 fprintf (file
, "{\n");
5031 fprintf (file
, "\n");
5033 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5034 if (ignore_topmost_bind
)
5035 fprintf (file
, "}\n");
5038 fprintf (file
, "\n\n");
5045 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
5048 debug_function (tree fn
, int flags
)
5050 dump_function_to_file (fn
, stderr
, flags
);
5054 /* Pretty print of the loops intermediate representation. */
5055 static void print_loop (FILE *, struct loop
*, int);
5056 static void print_pred_bbs (FILE *, basic_block bb
);
5057 static void print_succ_bbs (FILE *, basic_block bb
);
5060 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5063 print_pred_bbs (FILE *file
, basic_block bb
)
5068 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5069 fprintf (file
, "bb_%d ", e
->src
->index
);
5073 /* Print on FILE the indexes for the successors of basic_block BB. */
5076 print_succ_bbs (FILE *file
, basic_block bb
)
5081 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5082 fprintf (file
, "bb_%d ", e
->dest
->index
);
5086 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5089 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5097 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5098 memset ((void *) s_indent
, ' ', (size_t) indent
);
5099 s_indent
[indent
] = '\0';
5101 /* Print the loop's header. */
5102 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5104 /* Print the loop's body. */
5105 fprintf (file
, "%s{\n", s_indent
);
5107 if (bb
->loop_father
== loop
)
5109 /* Print the basic_block's header. */
5110 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5111 print_pred_bbs (file
, bb
);
5112 fprintf (file
, "}, succs = {");
5113 print_succ_bbs (file
, bb
);
5114 fprintf (file
, "})\n");
5116 /* Print the basic_block's body. */
5117 fprintf (file
, "%s {\n", s_indent
);
5118 tree_dump_bb (bb
, file
, indent
+ 4);
5119 fprintf (file
, "%s }\n", s_indent
);
5122 print_loop (file
, loop
->inner
, indent
+ 2);
5123 fprintf (file
, "%s}\n", s_indent
);
5124 print_loop (file
, loop
->next
, indent
);
5128 /* Follow a CFG edge from the entry point of the program, and on entry
5129 of a loop, pretty print the loop structure on FILE. */
5132 print_loop_ir (FILE *file
)
5136 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5137 if (bb
&& bb
->loop_father
)
5138 print_loop (file
, bb
->loop_father
, 0);
5142 /* Debugging loops structure at tree level. */
5145 debug_loop_ir (void)
5147 print_loop_ir (stderr
);
5151 /* Return true if BB ends with a call, possibly followed by some
5152 instructions that must stay with the call. Return false,
5156 tree_block_ends_with_call_p (basic_block bb
)
5158 block_stmt_iterator bsi
= bsi_last (bb
);
5159 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5163 /* Return true if BB ends with a conditional branch. Return false,
5167 tree_block_ends_with_condjump_p (basic_block bb
)
5169 tree stmt
= last_stmt (bb
);
5170 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5174 /* Return true if we need to add fake edge to exit at statement T.
5175 Helper function for tree_flow_call_edges_add. */
5178 need_fake_edge_p (tree t
)
5182 /* NORETURN and LONGJMP calls already have an edge to exit.
5183 CONST and PURE calls do not need one.
5184 We don't currently check for CONST and PURE here, although
5185 it would be a good idea, because those attributes are
5186 figured out from the RTL in mark_constant_function, and
5187 the counter incrementation code from -fprofile-arcs
5188 leads to different results from -fbranch-probabilities. */
5189 call
= get_call_expr_in (t
);
5191 && !(call_expr_flags (call
) & ECF_NORETURN
))
5194 if (TREE_CODE (t
) == ASM_EXPR
5195 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5202 /* Add fake edges to the function exit for any non constant and non
5203 noreturn calls, volatile inline assembly in the bitmap of blocks
5204 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5205 the number of blocks that were split.
5207 The goal is to expose cases in which entering a basic block does
5208 not imply that all subsequent instructions must be executed. */
5211 tree_flow_call_edges_add (sbitmap blocks
)
5214 int blocks_split
= 0;
5215 int last_bb
= last_basic_block
;
5216 bool check_last_block
= false;
5218 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5222 check_last_block
= true;
5224 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5226 /* In the last basic block, before epilogue generation, there will be
5227 a fallthru edge to EXIT. Special care is required if the last insn
5228 of the last basic block is a call because make_edge folds duplicate
5229 edges, which would result in the fallthru edge also being marked
5230 fake, which would result in the fallthru edge being removed by
5231 remove_fake_edges, which would result in an invalid CFG.
5233 Moreover, we can't elide the outgoing fake edge, since the block
5234 profiler needs to take this into account in order to solve the minimal
5235 spanning tree in the case that the call doesn't return.
5237 Handle this by adding a dummy instruction in a new last basic block. */
5238 if (check_last_block
)
5240 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5241 block_stmt_iterator bsi
= bsi_last (bb
);
5243 if (!bsi_end_p (bsi
))
5246 if (t
&& need_fake_edge_p (t
))
5250 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5253 bsi_insert_on_edge (e
, build_empty_stmt ());
5254 bsi_commit_edge_inserts ();
5259 /* Now add fake edges to the function exit for any non constant
5260 calls since there is no way that we can determine if they will
5262 for (i
= 0; i
< last_bb
; i
++)
5264 basic_block bb
= BASIC_BLOCK (i
);
5265 block_stmt_iterator bsi
;
5266 tree stmt
, last_stmt
;
5271 if (blocks
&& !TEST_BIT (blocks
, i
))
5274 bsi
= bsi_last (bb
);
5275 if (!bsi_end_p (bsi
))
5277 last_stmt
= bsi_stmt (bsi
);
5280 stmt
= bsi_stmt (bsi
);
5281 if (need_fake_edge_p (stmt
))
5284 /* The handling above of the final block before the
5285 epilogue should be enough to verify that there is
5286 no edge to the exit block in CFG already.
5287 Calling make_edge in such case would cause us to
5288 mark that edge as fake and remove it later. */
5289 #ifdef ENABLE_CHECKING
5290 if (stmt
== last_stmt
)
5292 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5293 gcc_assert (e
== NULL
);
5297 /* Note that the following may create a new basic block
5298 and renumber the existing basic blocks. */
5299 if (stmt
!= last_stmt
)
5301 e
= split_block (bb
, stmt
);
5305 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5309 while (!bsi_end_p (bsi
));
5314 verify_flow_info ();
5316 return blocks_split
;
5320 tree_purge_dead_eh_edges (basic_block bb
)
5322 bool changed
= false;
5325 tree stmt
= last_stmt (bb
);
5327 if (stmt
&& tree_can_throw_internal (stmt
))
5330 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5332 if (e
->flags
& EDGE_EH
)
5341 /* Removal of dead EH edges might change dominators of not
5342 just immediate successors. E.g. when bb1 is changed so that
5343 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5344 eh edges purged by this function in:
5356 idom(bb5) must be recomputed. For now just free the dominance
5359 free_dominance_info (CDI_DOMINATORS
);
5365 tree_purge_all_dead_eh_edges (bitmap blocks
)
5367 bool changed
= false;
5371 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5373 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5379 /* This function is called whenever a new edge is created or
5383 tree_execute_on_growing_pred (edge e
)
5385 basic_block bb
= e
->dest
;
5388 reserve_phi_args_for_new_edge (bb
);
5391 /* This function is called immediately before edge E is removed from
5392 the edge vector E->dest->preds. */
5395 tree_execute_on_shrinking_pred (edge e
)
5397 if (phi_nodes (e
->dest
))
5398 remove_phi_args (e
);
5401 /*---------------------------------------------------------------------------
5402 Helper functions for Loop versioning
5403 ---------------------------------------------------------------------------*/
5405 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5406 of 'first'. Both of them are dominated by 'new_head' basic block. When
5407 'new_head' was created by 'second's incoming edge it received phi arguments
5408 on the edge by split_edge(). Later, additional edge 'e' was created to
5409 connect 'new_head' and 'first'. Now this routine adds phi args on this
5410 additional edge 'e' that new_head to second edge received as part of edge
5415 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5416 basic_block new_head
, edge e
)
5419 edge e2
= find_edge (new_head
, second
);
5421 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5422 edge, we should always have an edge from NEW_HEAD to SECOND. */
5423 gcc_assert (e2
!= NULL
);
5425 /* Browse all 'second' basic block phi nodes and add phi args to
5426 edge 'e' for 'first' head. PHI args are always in correct order. */
5428 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5430 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5432 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5433 add_phi_arg (phi1
, def
, e
);
5437 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5438 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5439 the destination of the ELSE part. */
5441 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5442 basic_block cond_bb
, void *cond_e
)
5444 block_stmt_iterator bsi
;
5445 tree goto1
= NULL_TREE
;
5446 tree goto2
= NULL_TREE
;
5447 tree new_cond_expr
= NULL_TREE
;
5448 tree cond_expr
= (tree
) cond_e
;
5451 /* Build new conditional expr */
5452 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5453 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5454 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5456 /* Add new cond in cond_bb. */
5457 bsi
= bsi_start (cond_bb
);
5458 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5459 /* Adjust edges appropriately to connect new head with first head
5460 as well as second head. */
5461 e0
= single_succ_edge (cond_bb
);
5462 e0
->flags
&= ~EDGE_FALLTHRU
;
5463 e0
->flags
|= EDGE_FALSE_VALUE
;
5466 struct cfg_hooks tree_cfg_hooks
= {
5468 tree_verify_flow_info
,
5469 tree_dump_bb
, /* dump_bb */
5470 create_bb
, /* create_basic_block */
5471 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5472 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5473 remove_bb
, /* delete_basic_block */
5474 tree_split_block
, /* split_block */
5475 tree_move_block_after
, /* move_block_after */
5476 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5477 tree_merge_blocks
, /* merge_blocks */
5478 tree_predict_edge
, /* predict_edge */
5479 tree_predicted_by_p
, /* predicted_by_p */
5480 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5481 tree_duplicate_bb
, /* duplicate_block */
5482 tree_split_edge
, /* split_edge */
5483 tree_make_forwarder_block
, /* make_forward_block */
5484 NULL
, /* tidy_fallthru_edge */
5485 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5486 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5487 tree_flow_call_edges_add
, /* flow_call_edges_add */
5488 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5489 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5490 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5491 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5492 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5493 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5494 flush_pending_stmts
/* flush_pending_stmts */
5498 /* Split all critical edges. */
5501 split_critical_edges (void)
5507 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5508 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5509 mappings around the calls to split_edge. */
5510 start_recording_case_labels ();
5513 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5514 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5519 end_recording_case_labels ();
5523 struct tree_opt_pass pass_split_crit_edges
=
5525 "crited", /* name */
5527 split_critical_edges
, /* execute */
5530 0, /* static_pass_number */
5531 TV_TREE_SPLIT_EDGES
, /* tv_id */
5532 PROP_cfg
, /* properties required */
5533 PROP_no_crit_edges
, /* properties_provided */
5534 0, /* properties_destroyed */
5535 0, /* todo_flags_start */
5536 TODO_dump_func
, /* todo_flags_finish */
5541 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5542 a temporary, make sure and register it to be renamed if necessary,
5543 and finally return the temporary. Put the statements to compute
5544 EXP before the current statement in BSI. */
5547 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5549 tree t
, new_stmt
, orig_stmt
;
5551 if (is_gimple_val (exp
))
5554 t
= make_rename_temp (type
, NULL
);
5555 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5557 orig_stmt
= bsi_stmt (*bsi
);
5558 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5559 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5561 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5566 /* Build a ternary operation and gimplify it. Emit code before BSI.
5567 Return the gimple_val holding the result. */
5570 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5571 tree type
, tree a
, tree b
, tree c
)
5575 ret
= fold_build3 (code
, type
, a
, b
, c
);
5578 return gimplify_val (bsi
, type
, ret
);
5581 /* Build a binary operation and gimplify it. Emit code before BSI.
5582 Return the gimple_val holding the result. */
5585 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5586 tree type
, tree a
, tree b
)
5590 ret
= fold_build2 (code
, type
, a
, b
);
5593 return gimplify_val (bsi
, type
, ret
);
5596 /* Build a unary operation and gimplify it. Emit code before BSI.
5597 Return the gimple_val holding the result. */
5600 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5605 ret
= fold_build1 (code
, type
, a
);
5608 return gimplify_val (bsi
, type
, ret
);
5613 /* Emit return warnings. */
5616 execute_warn_function_return (void)
5618 #ifdef USE_MAPPED_LOCATION
5619 source_location location
;
5627 /* If we have a path to EXIT, then we do return. */
5628 if (TREE_THIS_VOLATILE (cfun
->decl
)
5629 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5631 #ifdef USE_MAPPED_LOCATION
5632 location
= UNKNOWN_LOCATION
;
5636 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5638 last
= last_stmt (e
->src
);
5639 if (TREE_CODE (last
) == RETURN_EXPR
5640 #ifdef USE_MAPPED_LOCATION
5641 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5643 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5647 #ifdef USE_MAPPED_LOCATION
5648 if (location
== UNKNOWN_LOCATION
)
5649 location
= cfun
->function_end_locus
;
5650 warning (0, "%H%<noreturn%> function does return", &location
);
5653 locus
= &cfun
->function_end_locus
;
5654 warning (0, "%H%<noreturn%> function does return", locus
);
5658 /* If we see "return;" in some basic block, then we do reach the end
5659 without returning a value. */
5660 else if (warn_return_type
5661 && !TREE_NO_WARNING (cfun
->decl
)
5662 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5663 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5665 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5667 tree last
= last_stmt (e
->src
);
5668 if (TREE_CODE (last
) == RETURN_EXPR
5669 && TREE_OPERAND (last
, 0) == NULL
5670 && !TREE_NO_WARNING (last
))
5672 #ifdef USE_MAPPED_LOCATION
5673 location
= EXPR_LOCATION (last
);
5674 if (location
== UNKNOWN_LOCATION
)
5675 location
= cfun
->function_end_locus
;
5676 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5678 locus
= EXPR_LOCUS (last
);
5680 locus
= &cfun
->function_end_locus
;
5681 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5683 TREE_NO_WARNING (cfun
->decl
) = 1;
5692 /* Given a basic block B which ends with a conditional and has
5693 precisely two successors, determine which of the edges is taken if
5694 the conditional is true and which is taken if the conditional is
5695 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5698 extract_true_false_edges_from_block (basic_block b
,
5702 edge e
= EDGE_SUCC (b
, 0);
5704 if (e
->flags
& EDGE_TRUE_VALUE
)
5707 *false_edge
= EDGE_SUCC (b
, 1);
5712 *true_edge
= EDGE_SUCC (b
, 1);
5716 struct tree_opt_pass pass_warn_function_return
=
5720 execute_warn_function_return
, /* execute */
5723 0, /* static_pass_number */
5725 PROP_cfg
, /* properties_required */
5726 0, /* properties_provided */
5727 0, /* properties_destroyed */
5728 0, /* todo_flags_start */
5729 0, /* todo_flags_finish */
5733 /* Emit noreturn warnings. */
5736 execute_warn_function_noreturn (void)
5738 if (warn_missing_noreturn
5739 && !TREE_THIS_VOLATILE (cfun
->decl
)
5740 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5741 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5742 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5743 "for attribute %<noreturn%>",
5748 struct tree_opt_pass pass_warn_function_noreturn
=
5752 execute_warn_function_noreturn
, /* execute */
5755 0, /* static_pass_number */
5757 PROP_cfg
, /* properties_required */
5758 0, /* properties_provided */
5759 0, /* properties_destroyed */
5760 0, /* todo_flags_start */
5761 0, /* todo_flags_finish */