1 /* Control flow functions for trees.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to
19 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
36 #include "langhooks.h"
37 #include "diagnostic.h"
38 #include "tree-flow.h"
40 #include "tree-dump.h"
41 #include "tree-pass.h"
45 #include "cfglayout.h"
47 #include "tree-ssa-propagate.h"
49 /* This file contains functions for building the Control Flow Graph (CFG)
50 for a function tree. */
52 /* Local declarations. */
54 /* Initial capacity for the basic block array. */
55 static const int initial_cfg_capacity
= 20;
57 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
58 which use a particular edge. The CASE_LABEL_EXPRs are chained together
59 via their TREE_CHAIN field, which we clear after we're done with the
60 hash table to prevent problems with duplication of SWITCH_EXPRs.
62 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
63 update the case vector in response to edge redirections.
65 Right now this table is set up and torn down at key points in the
66 compilation process. It would be nice if we could make the table
67 more persistent. The key is getting notification of changes to
68 the CFG (particularly edge removal, creation and redirection). */
70 struct edge_to_cases_elt
72 /* The edge itself. Necessary for hashing and equality tests. */
75 /* The case labels associated with this edge. We link these up via
76 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
77 when we destroy the hash table. This prevents problems when copying
82 static htab_t edge_to_cases
;
87 long num_merged_labels
;
90 static struct cfg_stats_d cfg_stats
;
92 /* Nonzero if we found a computed goto while building basic blocks. */
93 static bool found_computed_goto
;
95 /* Basic blocks and flowgraphs. */
96 static basic_block
create_bb (void *, void *, basic_block
);
97 static void make_blocks (tree
);
98 static void factor_computed_gotos (void);
101 static void make_edges (void);
102 static void make_ctrl_stmt_edges (basic_block
);
103 static void make_exit_edges (basic_block
);
104 static void make_cond_expr_edges (basic_block
);
105 static void make_switch_expr_edges (basic_block
);
106 static void make_goto_expr_edges (basic_block
);
107 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
108 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
109 static void split_critical_edges (void);
111 /* Various helpers. */
112 static inline bool stmt_starts_bb_p (tree
, tree
);
113 static int tree_verify_flow_info (void);
114 static void tree_make_forwarder_block (edge
);
115 static void tree_cfg2vcg (FILE *);
117 /* Flowgraph optimization and cleanup. */
118 static void tree_merge_blocks (basic_block
, basic_block
);
119 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
120 static void remove_bb (basic_block
);
121 static edge
find_taken_edge_computed_goto (basic_block
, tree
);
122 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
123 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
124 static tree
find_case_label_for_value (tree
, tree
);
127 init_empty_tree_cfg (void)
129 /* Initialize the basic block array. */
131 profile_status
= PROFILE_ABSENT
;
132 n_basic_blocks
= NUM_FIXED_BLOCKS
;
133 last_basic_block
= NUM_FIXED_BLOCKS
;
134 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 *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
213 tree_cfg2vcg (dump_file
);
214 dump_end (TDI_vcg
, dump_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
));
233 struct tree_opt_pass pass_build_cfg
=
237 execute_build_cfg
, /* execute */
240 0, /* static_pass_number */
241 TV_TREE_CFG
, /* tv_id */
242 PROP_gimple_leh
, /* properties_required */
243 PROP_cfg
, /* properties_provided */
244 0, /* properties_destroyed */
245 0, /* todo_flags_start */
246 TODO_verify_stmts
, /* todo_flags_finish */
250 /* Search the CFG for any computed gotos. If found, factor them to a
251 common computed goto site. Also record the location of that site so
252 that we can un-factor the gotos after we have converted back to
256 factor_computed_gotos (void)
259 tree factored_label_decl
= NULL
;
261 tree factored_computed_goto_label
= NULL
;
262 tree factored_computed_goto
= NULL
;
264 /* We know there are one or more computed gotos in this function.
265 Examine the last statement in each basic block to see if the block
266 ends with a computed goto. */
270 block_stmt_iterator bsi
= bsi_last (bb
);
275 last
= bsi_stmt (bsi
);
277 /* Ignore the computed goto we create when we factor the original
279 if (last
== factored_computed_goto
)
282 /* If the last statement is a computed goto, factor it. */
283 if (computed_goto_p (last
))
287 /* The first time we find a computed goto we need to create
288 the factored goto block and the variable each original
289 computed goto will use for their goto destination. */
290 if (! factored_computed_goto
)
292 basic_block new_bb
= create_empty_bb (bb
);
293 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
295 /* Create the destination of the factored goto. Each original
296 computed goto will put its desired destination into this
297 variable and jump to the label we create immediately
299 var
= create_tmp_var (ptr_type_node
, "gotovar");
301 /* Build a label for the new block which will contain the
302 factored computed goto. */
303 factored_label_decl
= create_artificial_label ();
304 factored_computed_goto_label
305 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
306 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
309 /* Build our new computed goto. */
310 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
311 bsi_insert_after (&new_bsi
, factored_computed_goto
,
315 /* Copy the original computed goto's destination into VAR. */
316 assignment
= build2 (MODIFY_EXPR
, ptr_type_node
,
317 var
, GOTO_DESTINATION (last
));
318 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
320 /* And re-vector the computed goto to the new destination. */
321 GOTO_DESTINATION (last
) = factored_label_decl
;
327 /* Build a flowgraph for the statement_list STMT_LIST. */
330 make_blocks (tree stmt_list
)
332 tree_stmt_iterator i
= tsi_start (stmt_list
);
334 bool start_new_block
= true;
335 bool first_stmt_of_list
= true;
336 basic_block bb
= ENTRY_BLOCK_PTR
;
338 while (!tsi_end_p (i
))
345 /* If the statement starts a new basic block or if we have determined
346 in a previous pass that we need to create a new block for STMT, do
348 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
350 if (!first_stmt_of_list
)
351 stmt_list
= tsi_split_statement_list_before (&i
);
352 bb
= create_basic_block (stmt_list
, NULL
, bb
);
353 start_new_block
= false;
356 /* Now add STMT to BB and create the subgraphs for special statement
358 set_bb_for_stmt (stmt
, bb
);
360 if (computed_goto_p (stmt
))
361 found_computed_goto
= true;
363 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
365 if (stmt_ends_bb_p (stmt
))
366 start_new_block
= true;
369 first_stmt_of_list
= false;
374 /* Create and return a new empty basic block after bb AFTER. */
377 create_bb (void *h
, void *e
, basic_block after
)
383 /* Create and initialize a new basic block. Since alloc_block uses
384 ggc_alloc_cleared to allocate a basic block, we do not have to
385 clear the newly allocated basic block here. */
388 bb
->index
= last_basic_block
;
390 bb
->stmt_list
= h
? (tree
) h
: alloc_stmt_list ();
392 /* Add the new block to the linked list of blocks. */
393 link_block (bb
, after
);
395 /* Grow the basic block array if needed. */
396 if ((size_t) last_basic_block
== VEC_length (basic_block
, basic_block_info
))
398 size_t old_size
= VEC_length (basic_block
, basic_block_info
);
399 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
401 VEC_safe_grow (basic_block
, gc
, basic_block_info
, new_size
);
402 p
= VEC_address (basic_block
, basic_block_info
);
403 memset (&p
[old_size
], 0, sizeof (basic_block
) * (new_size
- old_size
));
406 /* Add the newly created block to the array. */
407 SET_BASIC_BLOCK (last_basic_block
, bb
);
416 /*---------------------------------------------------------------------------
418 ---------------------------------------------------------------------------*/
420 /* Fold COND_EXPR_COND of each COND_EXPR. */
423 fold_cond_expr_cond (void)
429 tree stmt
= last_stmt (bb
);
432 && TREE_CODE (stmt
) == COND_EXPR
)
434 tree cond
= fold (COND_EXPR_COND (stmt
));
435 if (integer_zerop (cond
))
436 COND_EXPR_COND (stmt
) = boolean_false_node
;
437 else if (integer_onep (cond
))
438 COND_EXPR_COND (stmt
) = boolean_true_node
;
443 /* Join all the blocks in the flowgraph. */
450 /* Create an edge from entry to the first block with executable
452 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (NUM_FIXED_BLOCKS
), EDGE_FALLTHRU
);
454 /* Traverse the basic block array placing edges. */
457 tree first
= first_stmt (bb
);
458 tree last
= last_stmt (bb
);
462 /* Edges for statements that always alter flow control. */
463 if (is_ctrl_stmt (last
))
464 make_ctrl_stmt_edges (bb
);
466 /* Edges for statements that sometimes alter flow control. */
467 if (is_ctrl_altering_stmt (last
))
468 make_exit_edges (bb
);
471 /* Finally, if no edges were created above, this is a regular
472 basic block that only needs a fallthru edge. */
473 if (EDGE_COUNT (bb
->succs
) == 0)
474 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
477 /* We do not care about fake edges, so remove any that the CFG
478 builder inserted for completeness. */
479 remove_fake_exit_edges ();
481 /* Fold COND_EXPR_COND of each COND_EXPR. */
482 fold_cond_expr_cond ();
484 /* Clean up the graph and warn for unreachable code. */
489 /* Link an OMP_SECTIONS block to all the OMP_SECTION blocks in its body. */
492 make_omp_sections_edges (basic_block bb
)
498 stmt
= last_stmt (bb
);
499 vec
= OMP_SECTIONS_SECTIONS (stmt
);
500 n
= TREE_VEC_LENGTH (vec
);
501 exit_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, n
- 1));
503 for (i
= 0; i
< n
- 1; i
+= 2)
505 basic_block start_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, i
));
506 basic_block end_bb
= bb_for_stmt (TREE_VEC_ELT (vec
, i
+ 1));
507 make_edge (bb
, start_bb
, EDGE_ABNORMAL
);
508 make_edge (end_bb
, exit_bb
, EDGE_FALLTHRU
);
511 /* Once the CFG has been built, the vector of sections is no longer
512 useful. The region can be easily obtained with build_omp_regions.
513 Furthermore, this sharing of tree expressions is not allowed by the
514 statement verifier. */
515 OMP_SECTIONS_SECTIONS (stmt
) = NULL_TREE
;
520 /* Create edges for control statement at basic block BB. */
523 make_ctrl_stmt_edges (basic_block bb
)
525 tree last
= last_stmt (bb
);
528 switch (TREE_CODE (last
))
531 make_goto_expr_edges (bb
);
535 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
539 make_cond_expr_edges (bb
);
543 make_switch_expr_edges (bb
);
547 make_eh_edges (last
);
548 /* Yet another NORETURN hack. */
549 if (EDGE_COUNT (bb
->succs
) == 0)
550 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
559 /* Create exit edges for statements in block BB that alter the flow of
560 control. Statements that alter the control flow are 'goto', 'return'
561 and calls to non-returning functions. */
564 make_exit_edges (basic_block bb
)
566 tree last
= last_stmt (bb
), op
;
569 switch (TREE_CODE (last
))
574 /* If this function receives a nonlocal goto, then we need to
575 make edges from this call site to all the nonlocal goto
577 if (TREE_SIDE_EFFECTS (last
)
578 && current_function_has_nonlocal_label
)
579 make_goto_expr_edges (bb
);
581 /* If this statement has reachable exception handlers, then
582 create abnormal edges to them. */
583 make_eh_edges (last
);
585 /* Some calls are known not to return. For such calls we create
588 We really need to revamp how we build edges so that it's not
589 such a bloody pain to avoid creating edges for this case since
590 all we do is remove these edges when we're done building the
592 if (call_expr_flags (last
) & ECF_NORETURN
)
594 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
598 /* Don't forget the fall-thru edge. */
599 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
603 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
604 may have an abnormal edge. Search the RHS for this case and
605 create any required edges. */
606 op
= get_call_expr_in (last
);
607 if (op
&& TREE_SIDE_EFFECTS (op
)
608 && current_function_has_nonlocal_label
)
609 make_goto_expr_edges (bb
);
611 make_eh_edges (last
);
612 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
621 make_edge (bb
, bb
->next_bb
, EDGE_ABNORMAL
);
623 case OMP_RETURN_EXPR
:
624 if (EDGE_COUNT (bb
->succs
) == 0)
625 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
629 make_omp_sections_edges (bb
);
633 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
642 /* Create the edges for a COND_EXPR starting at block BB.
643 At this point, both clauses must contain only simple gotos. */
646 make_cond_expr_edges (basic_block bb
)
648 tree entry
= last_stmt (bb
);
649 basic_block then_bb
, else_bb
;
650 tree then_label
, else_label
;
654 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
656 /* Entry basic blocks for each component. */
657 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
658 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
659 then_bb
= label_to_block (then_label
);
660 else_bb
= label_to_block (else_label
);
662 e
= make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
663 #ifdef USE_MAPPED_LOCATION
664 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_THEN (entry
));
666 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_THEN (entry
));
668 e
= make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
671 #ifdef USE_MAPPED_LOCATION
672 e
->goto_locus
= EXPR_LOCATION (COND_EXPR_ELSE (entry
));
674 e
->goto_locus
= EXPR_LOCUS (COND_EXPR_ELSE (entry
));
679 /* Hashing routine for EDGE_TO_CASES. */
682 edge_to_cases_hash (const void *p
)
684 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
686 /* Hash on the edge itself (which is a pointer). */
687 return htab_hash_pointer (e
);
690 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
691 for equality is just a pointer comparison. */
694 edge_to_cases_eq (const void *p1
, const void *p2
)
696 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
697 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
702 /* Called for each element in the hash table (P) as we delete the
703 edge to cases hash table.
705 Clear all the TREE_CHAINs to prevent problems with copying of
706 SWITCH_EXPRs and structure sharing rules, then free the hash table
710 edge_to_cases_cleanup (void *p
)
712 struct edge_to_cases_elt
*elt
= (struct edge_to_cases_elt
*) p
;
715 for (t
= elt
->case_labels
; t
; t
= next
)
717 next
= TREE_CHAIN (t
);
718 TREE_CHAIN (t
) = NULL
;
723 /* Start recording information mapping edges to case labels. */
726 start_recording_case_labels (void)
728 gcc_assert (edge_to_cases
== NULL
);
730 edge_to_cases
= htab_create (37,
733 edge_to_cases_cleanup
);
736 /* Return nonzero if we are recording information for case labels. */
739 recording_case_labels_p (void)
741 return (edge_to_cases
!= NULL
);
744 /* Stop recording information mapping edges to case labels and
745 remove any information we have recorded. */
747 end_recording_case_labels (void)
749 htab_delete (edge_to_cases
);
750 edge_to_cases
= NULL
;
753 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
756 record_switch_edge (edge e
, tree case_label
)
758 struct edge_to_cases_elt
*elt
;
761 /* Build a hash table element so we can see if E is already
763 elt
= XNEW (struct edge_to_cases_elt
);
765 elt
->case_labels
= case_label
;
767 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
771 /* E was not in the hash table. Install E into the hash table. */
776 /* E was already in the hash table. Free ELT as we do not need it
780 /* Get the entry stored in the hash table. */
781 elt
= (struct edge_to_cases_elt
*) *slot
;
783 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
784 TREE_CHAIN (case_label
) = elt
->case_labels
;
785 elt
->case_labels
= case_label
;
789 /* If we are inside a {start,end}_recording_cases block, then return
790 a chain of CASE_LABEL_EXPRs from T which reference E.
792 Otherwise return NULL. */
795 get_cases_for_edge (edge e
, tree t
)
797 struct edge_to_cases_elt elt
, *elt_p
;
802 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
803 chains available. Return NULL so the caller can detect this case. */
804 if (!recording_case_labels_p ())
809 elt
.case_labels
= NULL
;
810 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
814 elt_p
= (struct edge_to_cases_elt
*)*slot
;
815 return elt_p
->case_labels
;
818 /* If we did not find E in the hash table, then this must be the first
819 time we have been queried for information about E & T. Add all the
820 elements from T to the hash table then perform the query again. */
822 vec
= SWITCH_LABELS (t
);
823 n
= TREE_VEC_LENGTH (vec
);
824 for (i
= 0; i
< n
; i
++)
826 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
827 basic_block label_bb
= label_to_block (lab
);
828 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
833 /* Create the edges for a SWITCH_EXPR starting at block BB.
834 At this point, the switch body has been lowered and the
835 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
838 make_switch_expr_edges (basic_block bb
)
840 tree entry
= last_stmt (bb
);
844 vec
= SWITCH_LABELS (entry
);
845 n
= TREE_VEC_LENGTH (vec
);
847 for (i
= 0; i
< n
; ++i
)
849 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
850 basic_block label_bb
= label_to_block (lab
);
851 make_edge (bb
, label_bb
, 0);
856 /* Return the basic block holding label DEST. */
859 label_to_block_fn (struct function
*ifun
, tree dest
)
861 int uid
= LABEL_DECL_UID (dest
);
863 /* We would die hard when faced by an undefined label. Emit a label to
864 the very first basic block. This will hopefully make even the dataflow
865 and undefined variable warnings quite right. */
866 if ((errorcount
|| sorrycount
) && uid
< 0)
868 block_stmt_iterator bsi
=
869 bsi_start (BASIC_BLOCK (NUM_FIXED_BLOCKS
));
872 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
873 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
874 uid
= LABEL_DECL_UID (dest
);
876 if (VEC_length (basic_block
, ifun
->cfg
->x_label_to_block_map
)
877 <= (unsigned int) uid
)
879 return VEC_index (basic_block
, ifun
->cfg
->x_label_to_block_map
, uid
);
882 /* Create edges for a goto statement at block BB. */
885 make_goto_expr_edges (basic_block bb
)
888 basic_block target_bb
;
890 block_stmt_iterator last
= bsi_last (bb
);
892 goto_t
= bsi_stmt (last
);
894 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
895 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
896 from a nonlocal goto. */
897 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
901 tree dest
= GOTO_DESTINATION (goto_t
);
904 /* A GOTO to a local label creates normal edges. */
905 if (simple_goto_p (goto_t
))
907 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
908 #ifdef USE_MAPPED_LOCATION
909 e
->goto_locus
= EXPR_LOCATION (goto_t
);
911 e
->goto_locus
= EXPR_LOCUS (goto_t
);
913 bsi_remove (&last
, true);
917 /* Nothing more to do for nonlocal gotos. */
918 if (TREE_CODE (dest
) == LABEL_DECL
)
921 /* Computed gotos remain. */
924 /* Look for the block starting with the destination label. In the
925 case of a computed goto, make an edge to any label block we find
927 FOR_EACH_BB (target_bb
)
929 block_stmt_iterator bsi
;
931 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
933 tree target
= bsi_stmt (bsi
);
935 if (TREE_CODE (target
) != LABEL_EXPR
)
939 /* Computed GOTOs. Make an edge to every label block that has
940 been marked as a potential target for a computed goto. */
941 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
942 /* Nonlocal GOTO target. Make an edge to every label block
943 that has been marked as a potential target for a nonlocal
945 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
947 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
953 /* Degenerate case of computed goto with no labels. */
954 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
955 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
959 /*---------------------------------------------------------------------------
961 ---------------------------------------------------------------------------*/
963 /* Cleanup useless labels in basic blocks. This is something we wish
964 to do early because it allows us to group case labels before creating
965 the edges for the CFG, and it speeds up block statement iterators in
967 We only run this pass once, running it more than once is probably not
970 /* A map from basic block index to the leading label of that block. */
971 static tree
*label_for_bb
;
973 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
975 update_eh_label (struct eh_region
*region
)
977 tree old_label
= get_eh_region_tree_label (region
);
981 basic_block bb
= label_to_block (old_label
);
983 /* ??? After optimizing, there may be EH regions with labels
984 that have already been removed from the function body, so
985 there is no basic block for them. */
989 new_label
= label_for_bb
[bb
->index
];
990 set_eh_region_tree_label (region
, new_label
);
994 /* Given LABEL return the first label in the same basic block. */
996 main_block_label (tree label
)
998 basic_block bb
= label_to_block (label
);
1000 /* label_to_block possibly inserted undefined label into the chain. */
1001 if (!label_for_bb
[bb
->index
])
1002 label_for_bb
[bb
->index
] = label
;
1003 return label_for_bb
[bb
->index
];
1006 /* Cleanup redundant labels. This is a three-step process:
1007 1) Find the leading label for each block.
1008 2) Redirect all references to labels to the leading labels.
1009 3) Cleanup all useless labels. */
1012 cleanup_dead_labels (void)
1015 label_for_bb
= XCNEWVEC (tree
, last_basic_block
);
1017 /* Find a suitable label for each block. We use the first user-defined
1018 label if there is one, or otherwise just the first label we see. */
1021 block_stmt_iterator i
;
1023 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
1025 tree label
, stmt
= bsi_stmt (i
);
1027 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1030 label
= LABEL_EXPR_LABEL (stmt
);
1032 /* If we have not yet seen a label for the current block,
1033 remember this one and see if there are more labels. */
1034 if (! label_for_bb
[bb
->index
])
1036 label_for_bb
[bb
->index
] = label
;
1040 /* If we did see a label for the current block already, but it
1041 is an artificially created label, replace it if the current
1042 label is a user defined label. */
1043 if (! DECL_ARTIFICIAL (label
)
1044 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
1046 label_for_bb
[bb
->index
] = label
;
1052 /* Now redirect all jumps/branches to the selected label.
1053 First do so for each block ending in a control statement. */
1056 tree stmt
= last_stmt (bb
);
1060 switch (TREE_CODE (stmt
))
1064 tree true_branch
, false_branch
;
1066 true_branch
= COND_EXPR_THEN (stmt
);
1067 false_branch
= COND_EXPR_ELSE (stmt
);
1069 GOTO_DESTINATION (true_branch
)
1070 = main_block_label (GOTO_DESTINATION (true_branch
));
1071 GOTO_DESTINATION (false_branch
)
1072 = main_block_label (GOTO_DESTINATION (false_branch
));
1080 tree vec
= SWITCH_LABELS (stmt
);
1081 size_t n
= TREE_VEC_LENGTH (vec
);
1083 /* Replace all destination labels. */
1084 for (i
= 0; i
< n
; ++i
)
1086 tree elt
= TREE_VEC_ELT (vec
, i
);
1087 tree label
= main_block_label (CASE_LABEL (elt
));
1088 CASE_LABEL (elt
) = label
;
1093 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1094 remove them until after we've created the CFG edges. */
1096 if (! computed_goto_p (stmt
))
1098 GOTO_DESTINATION (stmt
)
1099 = main_block_label (GOTO_DESTINATION (stmt
));
1108 for_each_eh_region (update_eh_label
);
1110 /* Finally, purge dead labels. All user-defined labels and labels that
1111 can be the target of non-local gotos are preserved. */
1114 block_stmt_iterator i
;
1115 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1117 if (! label_for_this_bb
)
1120 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1122 tree label
, stmt
= bsi_stmt (i
);
1124 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1127 label
= LABEL_EXPR_LABEL (stmt
);
1129 if (label
== label_for_this_bb
1130 || ! DECL_ARTIFICIAL (label
)
1131 || DECL_NONLOCAL (label
))
1134 bsi_remove (&i
, true);
1138 free (label_for_bb
);
1141 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1142 and scan the sorted vector of cases. Combine the ones jumping to the
1144 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1147 group_case_labels (void)
1153 tree stmt
= last_stmt (bb
);
1154 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1156 tree labels
= SWITCH_LABELS (stmt
);
1157 int old_size
= TREE_VEC_LENGTH (labels
);
1158 int i
, j
, new_size
= old_size
;
1159 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1162 /* The default label is always the last case in a switch
1163 statement after gimplification. */
1164 default_label
= CASE_LABEL (default_case
);
1166 /* Look for possible opportunities to merge cases.
1167 Ignore the last element of the label vector because it
1168 must be the default case. */
1170 while (i
< old_size
- 1)
1172 tree base_case
, base_label
, base_high
;
1173 base_case
= TREE_VEC_ELT (labels
, i
);
1175 gcc_assert (base_case
);
1176 base_label
= CASE_LABEL (base_case
);
1178 /* Discard cases that have the same destination as the
1180 if (base_label
== default_label
)
1182 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1188 base_high
= CASE_HIGH (base_case
) ?
1189 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1191 /* Try to merge case labels. Break out when we reach the end
1192 of the label vector or when we cannot merge the next case
1193 label with the current one. */
1194 while (i
< old_size
- 1)
1196 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1197 tree merge_label
= CASE_LABEL (merge_case
);
1198 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1199 integer_one_node
, 1);
1201 /* Merge the cases if they jump to the same place,
1202 and their ranges are consecutive. */
1203 if (merge_label
== base_label
1204 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1206 base_high
= CASE_HIGH (merge_case
) ?
1207 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1208 CASE_HIGH (base_case
) = base_high
;
1209 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1218 /* Compress the case labels in the label vector, and adjust the
1219 length of the vector. */
1220 for (i
= 0, j
= 0; i
< new_size
; i
++)
1222 while (! TREE_VEC_ELT (labels
, j
))
1224 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1226 TREE_VEC_LENGTH (labels
) = new_size
;
1231 /* Checks whether we can merge block B into block A. */
1234 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1237 block_stmt_iterator bsi
;
1240 if (!single_succ_p (a
))
1243 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1246 if (single_succ (a
) != b
)
1249 if (!single_pred_p (b
))
1252 if (b
== EXIT_BLOCK_PTR
)
1255 /* If A ends by a statement causing exceptions or something similar, we
1256 cannot merge the blocks. */
1257 stmt
= last_stmt (a
);
1258 if (stmt
&& stmt_ends_bb_p (stmt
))
1261 /* Do not allow a block with only a non-local label to be merged. */
1262 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1263 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1266 /* It must be possible to eliminate all phi nodes in B. If ssa form
1267 is not up-to-date, we cannot eliminate any phis. */
1268 phi
= phi_nodes (b
);
1271 if (need_ssa_update_p ())
1274 for (; phi
; phi
= PHI_CHAIN (phi
))
1275 if (!is_gimple_reg (PHI_RESULT (phi
))
1276 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1280 /* Do not remove user labels. */
1281 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1283 stmt
= bsi_stmt (bsi
);
1284 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1286 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1290 /* Protect the loop latches. */
1292 && b
->loop_father
->latch
== b
)
1298 /* Replaces all uses of NAME by VAL. */
1301 replace_uses_by (tree name
, tree val
)
1303 imm_use_iterator imm_iter
;
1308 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1310 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1312 stmt
= USE_STMT (use
);
1313 replace_exp (use
, val
);
1315 if (TREE_CODE (stmt
) == PHI_NODE
)
1317 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1318 if (e
->flags
& EDGE_ABNORMAL
)
1320 /* This can only occur for virtual operands, since
1321 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1322 would prevent replacement. */
1323 gcc_assert (!is_gimple_reg (name
));
1324 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1328 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1331 /* We do not update the statements in the loop above. Consider
1334 If we performed the update in the first loop, the statement
1335 would be rescanned after first occurrence of w is replaced,
1336 the new uses would be placed to the beginning of the list,
1337 and we would never process them. */
1338 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1342 fold_stmt_inplace (stmt
);
1344 rhs
= get_rhs (stmt
);
1345 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1346 recompute_tree_invariant_for_addr_expr (rhs
);
1348 /* If the statement could throw and now cannot, we need to prune cfg. */
1349 if (maybe_clean_or_replace_eh_stmt (stmt
, stmt
))
1350 tree_purge_dead_eh_edges (bb_for_stmt (stmt
));
1352 mark_new_vars_to_rename (stmt
);
1355 VEC_free (tree
, heap
, stmts
);
1357 /* Also update the trees stored in loop structures. */
1362 for (i
= 0; i
< current_loops
->num
; i
++)
1364 loop
= current_loops
->parray
[i
];
1366 substitute_in_loop_info (loop
, name
, val
);
1371 /* Merge block B into block A. */
1374 tree_merge_blocks (basic_block a
, basic_block b
)
1376 block_stmt_iterator bsi
;
1377 tree_stmt_iterator last
;
1381 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1383 /* Remove all single-valued PHI nodes from block B of the form
1384 V_i = PHI <V_j> by propagating V_j to all the uses of V_i. */
1386 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1388 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1390 bool may_replace_uses
= may_propagate_copy (def
, use
);
1392 /* In case we have loops to care about, do not propagate arguments of
1393 loop closed ssa phi nodes. */
1395 && is_gimple_reg (def
)
1396 && TREE_CODE (use
) == SSA_NAME
1397 && a
->loop_father
!= b
->loop_father
)
1398 may_replace_uses
= false;
1400 if (!may_replace_uses
)
1402 gcc_assert (is_gimple_reg (def
));
1404 /* Note that just emitting the copies is fine -- there is no problem
1405 with ordering of phi nodes. This is because A is the single
1406 predecessor of B, therefore results of the phi nodes cannot
1407 appear as arguments of the phi nodes. */
1408 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1409 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1410 SET_PHI_RESULT (phi
, NULL_TREE
);
1411 SSA_NAME_DEF_STMT (def
) = copy
;
1414 replace_uses_by (def
, use
);
1416 remove_phi_node (phi
, NULL
);
1419 /* Ensure that B follows A. */
1420 move_block_after (b
, a
);
1422 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1423 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1425 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1426 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1428 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1430 tree label
= bsi_stmt (bsi
);
1432 bsi_remove (&bsi
, false);
1433 /* Now that we can thread computed gotos, we might have
1434 a situation where we have a forced label in block B
1435 However, the label at the start of block B might still be
1436 used in other ways (think about the runtime checking for
1437 Fortran assigned gotos). So we can not just delete the
1438 label. Instead we move the label to the start of block A. */
1439 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1441 block_stmt_iterator dest_bsi
= bsi_start (a
);
1442 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1447 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1452 /* Merge the chains. */
1453 last
= tsi_last (a
->stmt_list
);
1454 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1455 b
->stmt_list
= NULL
;
1459 /* Return the one of two successors of BB that is not reachable by a
1460 reached by a complex edge, if there is one. Else, return BB. We use
1461 this in optimizations that use post-dominators for their heuristics,
1462 to catch the cases in C++ where function calls are involved. */
1465 single_noncomplex_succ (basic_block bb
)
1468 if (EDGE_COUNT (bb
->succs
) != 2)
1471 e0
= EDGE_SUCC (bb
, 0);
1472 e1
= EDGE_SUCC (bb
, 1);
1473 if (e0
->flags
& EDGE_COMPLEX
)
1475 if (e1
->flags
& EDGE_COMPLEX
)
1483 /* Walk the function tree removing unnecessary statements.
1485 * Empty statement nodes are removed
1487 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1489 * Unnecessary COND_EXPRs are removed
1491 * Some unnecessary BIND_EXPRs are removed
1493 Clearly more work could be done. The trick is doing the analysis
1494 and removal fast enough to be a net improvement in compile times.
1496 Note that when we remove a control structure such as a COND_EXPR
1497 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1498 to ensure we eliminate all the useless code. */
1509 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1512 remove_useless_stmts_warn_notreached (tree stmt
)
1514 if (EXPR_HAS_LOCATION (stmt
))
1516 location_t loc
= EXPR_LOCATION (stmt
);
1517 if (LOCATION_LINE (loc
) > 0)
1519 warning (0, "%Hwill never be executed", &loc
);
1524 switch (TREE_CODE (stmt
))
1526 case STATEMENT_LIST
:
1528 tree_stmt_iterator i
;
1529 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1530 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1536 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1538 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1540 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1544 case TRY_FINALLY_EXPR
:
1545 case TRY_CATCH_EXPR
:
1546 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1548 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1553 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1554 case EH_FILTER_EXPR
:
1555 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1557 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1560 /* Not a live container. */
1568 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1570 tree then_clause
, else_clause
, cond
;
1571 bool save_has_label
, then_has_label
, else_has_label
;
1573 save_has_label
= data
->has_label
;
1574 data
->has_label
= false;
1575 data
->last_goto
= NULL
;
1577 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1579 then_has_label
= data
->has_label
;
1580 data
->has_label
= false;
1581 data
->last_goto
= NULL
;
1583 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1585 else_has_label
= data
->has_label
;
1586 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1588 then_clause
= COND_EXPR_THEN (*stmt_p
);
1589 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1590 cond
= fold (COND_EXPR_COND (*stmt_p
));
1592 /* If neither arm does anything at all, we can remove the whole IF. */
1593 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1595 *stmt_p
= build_empty_stmt ();
1596 data
->repeat
= true;
1599 /* If there are no reachable statements in an arm, then we can
1600 zap the entire conditional. */
1601 else if (integer_nonzerop (cond
) && !else_has_label
)
1603 if (warn_notreached
)
1604 remove_useless_stmts_warn_notreached (else_clause
);
1605 *stmt_p
= then_clause
;
1606 data
->repeat
= true;
1608 else if (integer_zerop (cond
) && !then_has_label
)
1610 if (warn_notreached
)
1611 remove_useless_stmts_warn_notreached (then_clause
);
1612 *stmt_p
= else_clause
;
1613 data
->repeat
= true;
1616 /* Check a couple of simple things on then/else with single stmts. */
1619 tree then_stmt
= expr_only (then_clause
);
1620 tree else_stmt
= expr_only (else_clause
);
1622 /* Notice branches to a common destination. */
1623 if (then_stmt
&& else_stmt
1624 && TREE_CODE (then_stmt
) == GOTO_EXPR
1625 && TREE_CODE (else_stmt
) == GOTO_EXPR
1626 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1628 *stmt_p
= then_stmt
;
1629 data
->repeat
= true;
1632 /* If the THEN/ELSE clause merely assigns a value to a variable or
1633 parameter which is already known to contain that value, then
1634 remove the useless THEN/ELSE clause. */
1635 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1638 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1639 && TREE_OPERAND (else_stmt
, 0) == cond
1640 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1641 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1643 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1644 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1645 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1646 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1648 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1649 ? then_stmt
: else_stmt
);
1650 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1651 ? &COND_EXPR_THEN (*stmt_p
)
1652 : &COND_EXPR_ELSE (*stmt_p
));
1655 && TREE_CODE (stmt
) == MODIFY_EXPR
1656 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1657 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1658 *location
= alloc_stmt_list ();
1662 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1663 would be re-introduced during lowering. */
1664 data
->last_goto
= NULL
;
1669 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1671 bool save_may_branch
, save_may_throw
;
1672 bool this_may_branch
, this_may_throw
;
1674 /* Collect may_branch and may_throw information for the body only. */
1675 save_may_branch
= data
->may_branch
;
1676 save_may_throw
= data
->may_throw
;
1677 data
->may_branch
= false;
1678 data
->may_throw
= false;
1679 data
->last_goto
= NULL
;
1681 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1683 this_may_branch
= data
->may_branch
;
1684 this_may_throw
= data
->may_throw
;
1685 data
->may_branch
|= save_may_branch
;
1686 data
->may_throw
|= save_may_throw
;
1687 data
->last_goto
= NULL
;
1689 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1691 /* If the body is empty, then we can emit the FINALLY block without
1692 the enclosing TRY_FINALLY_EXPR. */
1693 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1695 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1696 data
->repeat
= true;
1699 /* If the handler is empty, then we can emit the TRY block without
1700 the enclosing TRY_FINALLY_EXPR. */
1701 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1703 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1704 data
->repeat
= true;
1707 /* If the body neither throws, nor branches, then we can safely
1708 string the TRY and FINALLY blocks together. */
1709 else if (!this_may_branch
&& !this_may_throw
)
1711 tree stmt
= *stmt_p
;
1712 *stmt_p
= TREE_OPERAND (stmt
, 0);
1713 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1714 data
->repeat
= true;
1720 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1722 bool save_may_throw
, this_may_throw
;
1723 tree_stmt_iterator i
;
1726 /* Collect may_throw information for the body only. */
1727 save_may_throw
= data
->may_throw
;
1728 data
->may_throw
= false;
1729 data
->last_goto
= NULL
;
1731 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1733 this_may_throw
= data
->may_throw
;
1734 data
->may_throw
= save_may_throw
;
1736 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1737 if (!this_may_throw
)
1739 if (warn_notreached
)
1740 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1741 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1742 data
->repeat
= true;
1746 /* Process the catch clause specially. We may be able to tell that
1747 no exceptions propagate past this point. */
1749 this_may_throw
= true;
1750 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1751 stmt
= tsi_stmt (i
);
1752 data
->last_goto
= NULL
;
1754 switch (TREE_CODE (stmt
))
1757 for (; !tsi_end_p (i
); tsi_next (&i
))
1759 stmt
= tsi_stmt (i
);
1760 /* If we catch all exceptions, then the body does not
1761 propagate exceptions past this point. */
1762 if (CATCH_TYPES (stmt
) == NULL
)
1763 this_may_throw
= false;
1764 data
->last_goto
= NULL
;
1765 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1769 case EH_FILTER_EXPR
:
1770 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1771 this_may_throw
= false;
1772 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1773 this_may_throw
= false;
1774 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1778 /* Otherwise this is a cleanup. */
1779 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1781 /* If the cleanup is empty, then we can emit the TRY block without
1782 the enclosing TRY_CATCH_EXPR. */
1783 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1785 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1786 data
->repeat
= true;
1790 data
->may_throw
|= this_may_throw
;
1795 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1799 /* First remove anything underneath the BIND_EXPR. */
1800 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1802 /* If the BIND_EXPR has no variables, then we can pull everything
1803 up one level and remove the BIND_EXPR, unless this is the toplevel
1804 BIND_EXPR for the current function or an inlined function.
1806 When this situation occurs we will want to apply this
1807 optimization again. */
1808 block
= BIND_EXPR_BLOCK (*stmt_p
);
1809 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1810 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1812 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1813 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1816 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1817 data
->repeat
= true;
1823 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1825 tree dest
= GOTO_DESTINATION (*stmt_p
);
1827 data
->may_branch
= true;
1828 data
->last_goto
= NULL
;
1830 /* Record the last goto expr, so that we can delete it if unnecessary. */
1831 if (TREE_CODE (dest
) == LABEL_DECL
)
1832 data
->last_goto
= stmt_p
;
1837 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1839 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1841 data
->has_label
= true;
1843 /* We do want to jump across non-local label receiver code. */
1844 if (DECL_NONLOCAL (label
))
1845 data
->last_goto
= NULL
;
1847 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1849 *data
->last_goto
= build_empty_stmt ();
1850 data
->repeat
= true;
1853 /* ??? Add something here to delete unused labels. */
1857 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1858 decl. This allows us to eliminate redundant or useless
1859 calls to "const" functions.
1861 Gimplifier already does the same operation, but we may notice functions
1862 being const and pure once their calls has been gimplified, so we need
1863 to update the flag. */
1866 update_call_expr_flags (tree call
)
1868 tree decl
= get_callee_fndecl (call
);
1871 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1872 TREE_SIDE_EFFECTS (call
) = 0;
1873 if (TREE_NOTHROW (decl
))
1874 TREE_NOTHROW (call
) = 1;
1878 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1881 notice_special_calls (tree t
)
1883 int flags
= call_expr_flags (t
);
1885 if (flags
& ECF_MAY_BE_ALLOCA
)
1886 current_function_calls_alloca
= true;
1887 if (flags
& ECF_RETURNS_TWICE
)
1888 current_function_calls_setjmp
= true;
1892 /* Clear flags set by notice_special_calls. Used by dead code removal
1893 to update the flags. */
1896 clear_special_calls (void)
1898 current_function_calls_alloca
= false;
1899 current_function_calls_setjmp
= false;
1904 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1908 switch (TREE_CODE (t
))
1911 remove_useless_stmts_cond (tp
, data
);
1914 case TRY_FINALLY_EXPR
:
1915 remove_useless_stmts_tf (tp
, data
);
1918 case TRY_CATCH_EXPR
:
1919 remove_useless_stmts_tc (tp
, data
);
1923 remove_useless_stmts_bind (tp
, data
);
1927 remove_useless_stmts_goto (tp
, data
);
1931 remove_useless_stmts_label (tp
, data
);
1936 data
->last_goto
= NULL
;
1937 data
->may_branch
= true;
1942 data
->last_goto
= NULL
;
1943 notice_special_calls (t
);
1944 update_call_expr_flags (t
);
1945 if (tree_could_throw_p (t
))
1946 data
->may_throw
= true;
1950 data
->last_goto
= NULL
;
1952 op
= get_call_expr_in (t
);
1955 update_call_expr_flags (op
);
1956 notice_special_calls (op
);
1958 if (tree_could_throw_p (t
))
1959 data
->may_throw
= true;
1962 case STATEMENT_LIST
:
1964 tree_stmt_iterator i
= tsi_start (t
);
1965 while (!tsi_end_p (i
))
1968 if (IS_EMPTY_STMT (t
))
1974 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1977 if (TREE_CODE (t
) == STATEMENT_LIST
)
1979 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1989 data
->last_goto
= NULL
;
1993 data
->last_goto
= NULL
;
1999 remove_useless_stmts (void)
2001 struct rus_data data
;
2003 clear_special_calls ();
2007 memset (&data
, 0, sizeof (data
));
2008 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
2010 while (data
.repeat
);
2014 struct tree_opt_pass pass_remove_useless_stmts
=
2016 "useless", /* name */
2018 remove_useless_stmts
, /* execute */
2021 0, /* static_pass_number */
2023 PROP_gimple_any
, /* properties_required */
2024 0, /* properties_provided */
2025 0, /* properties_destroyed */
2026 0, /* todo_flags_start */
2027 TODO_dump_func
, /* todo_flags_finish */
2031 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
2034 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
2038 /* Since this block is no longer reachable, we can just delete all
2039 of its PHI nodes. */
2040 phi
= phi_nodes (bb
);
2043 tree next
= PHI_CHAIN (phi
);
2044 remove_phi_node (phi
, NULL_TREE
);
2048 /* Remove edges to BB's successors. */
2049 while (EDGE_COUNT (bb
->succs
) > 0)
2050 remove_edge (EDGE_SUCC (bb
, 0));
2054 /* Remove statements of basic block BB. */
2057 remove_bb (basic_block bb
)
2059 block_stmt_iterator i
;
2060 #ifdef USE_MAPPED_LOCATION
2061 source_location loc
= UNKNOWN_LOCATION
;
2063 source_locus loc
= 0;
2068 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
2069 if (dump_flags
& TDF_DETAILS
)
2071 dump_bb (bb
, dump_file
, 0);
2072 fprintf (dump_file
, "\n");
2076 /* If we remove the header or the latch of a loop, mark the loop for
2077 removal by setting its header and latch to NULL. */
2080 struct loop
*loop
= bb
->loop_father
;
2082 if (loop
->latch
== bb
2083 || loop
->header
== bb
)
2086 loop
->header
= NULL
;
2088 /* Also clean up the information associated with the loop. Updating
2089 it would waste time. More importantly, it may refer to ssa
2090 names that were defined in other removed basic block -- these
2091 ssa names are now removed and invalid. */
2092 free_numbers_of_iterations_estimates_loop (loop
);
2096 /* Remove all the instructions in the block. */
2097 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2099 tree stmt
= bsi_stmt (i
);
2100 if (TREE_CODE (stmt
) == LABEL_EXPR
2101 && (FORCED_LABEL (LABEL_EXPR_LABEL (stmt
))
2102 || DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
))))
2105 block_stmt_iterator new_bsi
;
2107 /* A non-reachable non-local label may still be referenced.
2108 But it no longer needs to carry the extra semantics of
2110 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
2112 DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)) = 0;
2113 FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)) = 1;
2116 new_bb
= bb
->prev_bb
;
2117 new_bsi
= bsi_start (new_bb
);
2118 bsi_remove (&i
, false);
2119 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2123 /* Release SSA definitions if we are in SSA. Note that we
2124 may be called when not in SSA. For example,
2125 final_cleanup calls this function via
2126 cleanup_tree_cfg. */
2128 release_defs (stmt
);
2130 bsi_remove (&i
, true);
2133 /* Don't warn for removed gotos. Gotos are often removed due to
2134 jump threading, thus resulting in bogus warnings. Not great,
2135 since this way we lose warnings for gotos in the original
2136 program that are indeed unreachable. */
2137 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2139 #ifdef USE_MAPPED_LOCATION
2140 if (EXPR_HAS_LOCATION (stmt
))
2141 loc
= EXPR_LOCATION (stmt
);
2144 t
= EXPR_LOCUS (stmt
);
2145 if (t
&& LOCATION_LINE (*t
) > 0)
2151 /* If requested, give a warning that the first statement in the
2152 block is unreachable. We walk statements backwards in the
2153 loop above, so the last statement we process is the first statement
2155 #ifdef USE_MAPPED_LOCATION
2156 if (loc
> BUILTINS_LOCATION
)
2157 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2160 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2163 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2167 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2168 predicate VAL, return the edge that will be taken out of the block.
2169 If VAL does not match a unique edge, NULL is returned. */
2172 find_taken_edge (basic_block bb
, tree val
)
2176 stmt
= last_stmt (bb
);
2179 gcc_assert (is_ctrl_stmt (stmt
));
2182 if (! is_gimple_min_invariant (val
))
2185 if (TREE_CODE (stmt
) == COND_EXPR
)
2186 return find_taken_edge_cond_expr (bb
, val
);
2188 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2189 return find_taken_edge_switch_expr (bb
, val
);
2191 if (computed_goto_p (stmt
))
2192 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2197 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2198 statement, determine which of the outgoing edges will be taken out of the
2199 block. Return NULL if either edge may be taken. */
2202 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2207 dest
= label_to_block (val
);
2210 e
= find_edge (bb
, dest
);
2211 gcc_assert (e
!= NULL
);
2217 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2218 statement, determine which of the two edges will be taken out of the
2219 block. Return NULL if either edge may be taken. */
2222 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2224 edge true_edge
, false_edge
;
2226 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2228 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2229 return (zero_p (val
) ? false_edge
: true_edge
);
2232 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2233 statement, determine which edge will be taken out of the block. Return
2234 NULL if any edge may be taken. */
2237 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2239 tree switch_expr
, taken_case
;
2240 basic_block dest_bb
;
2243 switch_expr
= last_stmt (bb
);
2244 taken_case
= find_case_label_for_value (switch_expr
, val
);
2245 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2247 e
= find_edge (bb
, dest_bb
);
2253 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2254 We can make optimal use here of the fact that the case labels are
2255 sorted: We can do a binary search for a case matching VAL. */
2258 find_case_label_for_value (tree switch_expr
, tree val
)
2260 tree vec
= SWITCH_LABELS (switch_expr
);
2261 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2262 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2264 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2266 size_t i
= (high
+ low
) / 2;
2267 tree t
= TREE_VEC_ELT (vec
, i
);
2270 /* Cache the result of comparing CASE_LOW and val. */
2271 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2278 if (CASE_HIGH (t
) == NULL
)
2280 /* A singe-valued case label. */
2286 /* A case range. We can only handle integer ranges. */
2287 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2292 return default_case
;
2298 /*---------------------------------------------------------------------------
2300 ---------------------------------------------------------------------------*/
2302 /* Dump tree-specific information of block BB to file OUTF. */
2305 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2307 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2311 /* Dump a basic block on stderr. */
2314 debug_tree_bb (basic_block bb
)
2316 dump_bb (bb
, stderr
, 0);
2320 /* Dump basic block with index N on stderr. */
2323 debug_tree_bb_n (int n
)
2325 debug_tree_bb (BASIC_BLOCK (n
));
2326 return BASIC_BLOCK (n
);
2330 /* Dump the CFG on stderr.
2332 FLAGS are the same used by the tree dumping functions
2333 (see TDF_* in tree.h). */
2336 debug_tree_cfg (int flags
)
2338 dump_tree_cfg (stderr
, flags
);
2342 /* Dump the program showing basic block boundaries on the given FILE.
2344 FLAGS are the same used by the tree dumping functions (see TDF_* in
2348 dump_tree_cfg (FILE *file
, int flags
)
2350 if (flags
& TDF_DETAILS
)
2352 const char *funcname
2353 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2356 fprintf (file
, ";; Function %s\n\n", funcname
);
2357 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2358 n_basic_blocks
, n_edges
, last_basic_block
);
2360 brief_dump_cfg (file
);
2361 fprintf (file
, "\n");
2364 if (flags
& TDF_STATS
)
2365 dump_cfg_stats (file
);
2367 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2371 /* Dump CFG statistics on FILE. */
2374 dump_cfg_stats (FILE *file
)
2376 static long max_num_merged_labels
= 0;
2377 unsigned long size
, total
= 0;
2380 const char * const fmt_str
= "%-30s%-13s%12s\n";
2381 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2382 const char * const fmt_str_2
= "%-30s%13ld%11lu%c\n";
2383 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2384 const char *funcname
2385 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2388 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2390 fprintf (file
, "---------------------------------------------------------\n");
2391 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2392 fprintf (file
, fmt_str
, "", " instances ", "used ");
2393 fprintf (file
, "---------------------------------------------------------\n");
2395 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2397 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2398 SCALE (size
), LABEL (size
));
2402 num_edges
+= EDGE_COUNT (bb
->succs
);
2403 size
= num_edges
* sizeof (struct edge_def
);
2405 fprintf (file
, fmt_str_2
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2407 fprintf (file
, "---------------------------------------------------------\n");
2408 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2410 fprintf (file
, "---------------------------------------------------------\n");
2411 fprintf (file
, "\n");
2413 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2414 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2416 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2417 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2419 fprintf (file
, "\n");
2423 /* Dump CFG statistics on stderr. Keep extern so that it's always
2424 linked in the final executable. */
2427 debug_cfg_stats (void)
2429 dump_cfg_stats (stderr
);
2433 /* Dump the flowgraph to a .vcg FILE. */
2436 tree_cfg2vcg (FILE *file
)
2441 const char *funcname
2442 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2444 /* Write the file header. */
2445 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2446 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2447 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2449 /* Write blocks and edges. */
2450 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2452 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2455 if (e
->flags
& EDGE_FAKE
)
2456 fprintf (file
, " linestyle: dotted priority: 10");
2458 fprintf (file
, " linestyle: solid priority: 100");
2460 fprintf (file
, " }\n");
2466 enum tree_code head_code
, end_code
;
2467 const char *head_name
, *end_name
;
2470 tree first
= first_stmt (bb
);
2471 tree last
= last_stmt (bb
);
2475 head_code
= TREE_CODE (first
);
2476 head_name
= tree_code_name
[head_code
];
2477 head_line
= get_lineno (first
);
2480 head_name
= "no-statement";
2484 end_code
= TREE_CODE (last
);
2485 end_name
= tree_code_name
[end_code
];
2486 end_line
= get_lineno (last
);
2489 end_name
= "no-statement";
2491 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2492 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2495 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2497 if (e
->dest
== EXIT_BLOCK_PTR
)
2498 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2500 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2502 if (e
->flags
& EDGE_FAKE
)
2503 fprintf (file
, " priority: 10 linestyle: dotted");
2505 fprintf (file
, " priority: 100 linestyle: solid");
2507 fprintf (file
, " }\n");
2510 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2514 fputs ("}\n\n", file
);
2519 /*---------------------------------------------------------------------------
2520 Miscellaneous helpers
2521 ---------------------------------------------------------------------------*/
2523 /* Return true if T represents a stmt that always transfers control. */
2526 is_ctrl_stmt (tree t
)
2528 return (TREE_CODE (t
) == COND_EXPR
2529 || TREE_CODE (t
) == SWITCH_EXPR
2530 || TREE_CODE (t
) == GOTO_EXPR
2531 || TREE_CODE (t
) == RETURN_EXPR
2532 || TREE_CODE (t
) == RESX_EXPR
);
2536 /* Return true if T is a statement that may alter the flow of control
2537 (e.g., a call to a non-returning function). */
2540 is_ctrl_altering_stmt (tree t
)
2545 call
= get_call_expr_in (t
);
2548 /* A non-pure/const CALL_EXPR alters flow control if the current
2549 function has nonlocal labels. */
2550 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2553 /* A CALL_EXPR also alters control flow if it does not return. */
2554 if (call_expr_flags (call
) & ECF_NORETURN
)
2558 /* OpenMP directives alter control flow. */
2559 if (flag_openmp
&& OMP_DIRECTIVE_P (t
))
2562 /* If a statement can throw, it alters control flow. */
2563 return tree_can_throw_internal (t
);
2567 /* Return true if T is a computed goto. */
2570 computed_goto_p (tree t
)
2572 return (TREE_CODE (t
) == GOTO_EXPR
2573 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2577 /* Checks whether EXPR is a simple local goto. */
2580 simple_goto_p (tree expr
)
2582 return (TREE_CODE (expr
) == GOTO_EXPR
2583 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2587 /* Return true if T should start a new basic block. PREV_T is the
2588 statement preceding T. It is used when T is a label or a case label.
2589 Labels should only start a new basic block if their previous statement
2590 wasn't a label. Otherwise, sequence of labels would generate
2591 unnecessary basic blocks that only contain a single label. */
2594 stmt_starts_bb_p (tree t
, tree prev_t
)
2599 /* LABEL_EXPRs start a new basic block only if the preceding
2600 statement wasn't a label of the same type. This prevents the
2601 creation of consecutive blocks that have nothing but a single
2603 if (TREE_CODE (t
) == LABEL_EXPR
)
2605 /* Nonlocal and computed GOTO targets always start a new block. */
2606 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2607 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2610 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2612 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2615 cfg_stats
.num_merged_labels
++;
2626 /* Return true if T should end a basic block. */
2629 stmt_ends_bb_p (tree t
)
2631 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2635 /* Add gotos that used to be represented implicitly in the CFG. */
2638 disband_implicit_edges (void)
2641 block_stmt_iterator last
;
2648 last
= bsi_last (bb
);
2649 stmt
= last_stmt (bb
);
2651 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2653 /* Remove superfluous gotos from COND_EXPR branches. Moved
2654 from cfg_remove_useless_stmts here since it violates the
2655 invariants for tree--cfg correspondence and thus fits better
2656 here where we do it anyway. */
2657 e
= find_edge (bb
, bb
->next_bb
);
2660 if (e
->flags
& EDGE_TRUE_VALUE
)
2661 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2662 else if (e
->flags
& EDGE_FALSE_VALUE
)
2663 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2666 e
->flags
|= EDGE_FALLTHRU
;
2672 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2674 /* Remove the RETURN_EXPR if we may fall though to the exit
2676 gcc_assert (single_succ_p (bb
));
2677 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2679 if (bb
->next_bb
== EXIT_BLOCK_PTR
2680 && !TREE_OPERAND (stmt
, 0))
2682 bsi_remove (&last
, true);
2683 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2688 /* There can be no fallthru edge if the last statement is a control
2690 if (stmt
&& is_ctrl_stmt (stmt
))
2693 /* Find a fallthru edge and emit the goto if necessary. */
2694 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2695 if (e
->flags
& EDGE_FALLTHRU
)
2698 if (!e
|| e
->dest
== bb
->next_bb
)
2701 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2702 label
= tree_block_label (e
->dest
);
2704 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2705 #ifdef USE_MAPPED_LOCATION
2706 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2708 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2710 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2711 e
->flags
&= ~EDGE_FALLTHRU
;
2715 /* Remove block annotations and other datastructures. */
2718 delete_tree_cfg_annotations (void)
2720 label_to_block_map
= NULL
;
2724 /* Return the first statement in basic block BB. */
2727 first_stmt (basic_block bb
)
2729 block_stmt_iterator i
= bsi_start (bb
);
2730 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2734 /* Return the last statement in basic block BB. */
2737 last_stmt (basic_block bb
)
2739 block_stmt_iterator b
= bsi_last (bb
);
2740 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2744 /* Return a pointer to the last statement in block BB. */
2747 last_stmt_ptr (basic_block bb
)
2749 block_stmt_iterator last
= bsi_last (bb
);
2750 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2754 /* Return the last statement of an otherwise empty block. Return NULL
2755 if the block is totally empty, or if it contains more than one
2759 last_and_only_stmt (basic_block bb
)
2761 block_stmt_iterator i
= bsi_last (bb
);
2767 last
= bsi_stmt (i
);
2772 /* Empty statements should no longer appear in the instruction stream.
2773 Everything that might have appeared before should be deleted by
2774 remove_useless_stmts, and the optimizers should just bsi_remove
2775 instead of smashing with build_empty_stmt.
2777 Thus the only thing that should appear here in a block containing
2778 one executable statement is a label. */
2779 prev
= bsi_stmt (i
);
2780 if (TREE_CODE (prev
) == LABEL_EXPR
)
2787 /* Mark BB as the basic block holding statement T. */
2790 set_bb_for_stmt (tree t
, basic_block bb
)
2792 if (TREE_CODE (t
) == PHI_NODE
)
2794 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2796 tree_stmt_iterator i
;
2797 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2798 set_bb_for_stmt (tsi_stmt (i
), bb
);
2802 stmt_ann_t ann
= get_stmt_ann (t
);
2805 /* If the statement is a label, add the label to block-to-labels map
2806 so that we can speed up edge creation for GOTO_EXPRs. */
2807 if (TREE_CODE (t
) == LABEL_EXPR
)
2811 t
= LABEL_EXPR_LABEL (t
);
2812 uid
= LABEL_DECL_UID (t
);
2815 unsigned old_len
= VEC_length (basic_block
, label_to_block_map
);
2816 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2817 if (old_len
<= (unsigned) uid
)
2820 unsigned new_len
= 3 * uid
/ 2;
2822 VEC_safe_grow (basic_block
, gc
, label_to_block_map
,
2824 addr
= VEC_address (basic_block
, label_to_block_map
);
2825 memset (&addr
[old_len
],
2826 0, sizeof (basic_block
) * (new_len
- old_len
));
2830 /* We're moving an existing label. Make sure that we've
2831 removed it from the old block. */
2833 || !VEC_index (basic_block
, label_to_block_map
, uid
));
2834 VEC_replace (basic_block
, label_to_block_map
, uid
, bb
);
2839 /* Finds iterator for STMT. */
2841 extern block_stmt_iterator
2842 bsi_for_stmt (tree stmt
)
2844 block_stmt_iterator bsi
;
2846 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2847 if (bsi_stmt (bsi
) == stmt
)
2853 /* Mark statement T as modified, and update it. */
2855 update_modified_stmts (tree t
)
2857 if (TREE_CODE (t
) == STATEMENT_LIST
)
2859 tree_stmt_iterator i
;
2861 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2863 stmt
= tsi_stmt (i
);
2864 update_stmt_if_modified (stmt
);
2868 update_stmt_if_modified (t
);
2871 /* Insert statement (or statement list) T before the statement
2872 pointed-to by iterator I. M specifies how to update iterator I
2873 after insertion (see enum bsi_iterator_update). */
2876 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2878 set_bb_for_stmt (t
, i
->bb
);
2879 update_modified_stmts (t
);
2880 tsi_link_before (&i
->tsi
, t
, m
);
2884 /* Insert statement (or statement list) T after the statement
2885 pointed-to by iterator I. M specifies how to update iterator I
2886 after insertion (see enum bsi_iterator_update). */
2889 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2891 set_bb_for_stmt (t
, i
->bb
);
2892 update_modified_stmts (t
);
2893 tsi_link_after (&i
->tsi
, t
, m
);
2897 /* Remove the statement pointed to by iterator I. The iterator is updated
2898 to the next statement.
2900 When REMOVE_EH_INFO is true we remove the statement pointed to by
2901 iterator I from the EH tables. Otherwise we do not modify the EH
2904 Generally, REMOVE_EH_INFO should be true when the statement is going to
2905 be removed from the IL and not reinserted elsewhere. */
2908 bsi_remove (block_stmt_iterator
*i
, bool remove_eh_info
)
2910 tree t
= bsi_stmt (*i
);
2911 set_bb_for_stmt (t
, NULL
);
2912 delink_stmt_imm_use (t
);
2913 tsi_delink (&i
->tsi
);
2914 mark_stmt_modified (t
);
2916 remove_stmt_from_eh_region (t
);
2920 /* Move the statement at FROM so it comes right after the statement at TO. */
2923 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2925 tree stmt
= bsi_stmt (*from
);
2926 bsi_remove (from
, false);
2927 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2931 /* Move the statement at FROM so it comes right before the statement at TO. */
2934 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2936 tree stmt
= bsi_stmt (*from
);
2937 bsi_remove (from
, false);
2938 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2942 /* Move the statement at FROM to the end of basic block BB. */
2945 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2947 block_stmt_iterator last
= bsi_last (bb
);
2949 /* Have to check bsi_end_p because it could be an empty block. */
2950 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2951 bsi_move_before (from
, &last
);
2953 bsi_move_after (from
, &last
);
2957 /* Replace the contents of the statement pointed to by iterator BSI
2958 with STMT. If UPDATE_EH_INFO is true, the exception handling
2959 information of the original statement is moved to the new statement. */
2963 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool update_eh_info
)
2966 tree orig_stmt
= bsi_stmt (*bsi
);
2968 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2969 set_bb_for_stmt (stmt
, bsi
->bb
);
2971 /* Preserve EH region information from the original statement, if
2972 requested by the caller. */
2975 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2978 remove_stmt_from_eh_region (orig_stmt
);
2979 add_stmt_to_eh_region (stmt
, eh_region
);
2983 delink_stmt_imm_use (orig_stmt
);
2984 *bsi_stmt_ptr (*bsi
) = stmt
;
2985 mark_stmt_modified (stmt
);
2986 update_modified_stmts (stmt
);
2990 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2991 is made to place the statement in an existing basic block, but
2992 sometimes that isn't possible. When it isn't possible, the edge is
2993 split and the statement is added to the new block.
2995 In all cases, the returned *BSI points to the correct location. The
2996 return value is true if insertion should be done after the location,
2997 or false if it should be done before the location. If new basic block
2998 has to be created, it is stored in *NEW_BB. */
3001 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
3002 basic_block
*new_bb
)
3004 basic_block dest
, src
;
3010 /* If the destination has one predecessor which has no PHI nodes,
3011 insert there. Except for the exit block.
3013 The requirement for no PHI nodes could be relaxed. Basically we
3014 would have to examine the PHIs to prove that none of them used
3015 the value set by the statement we want to insert on E. That
3016 hardly seems worth the effort. */
3017 if (single_pred_p (dest
)
3018 && ! phi_nodes (dest
)
3019 && dest
!= EXIT_BLOCK_PTR
)
3021 *bsi
= bsi_start (dest
);
3022 if (bsi_end_p (*bsi
))
3025 /* Make sure we insert after any leading labels. */
3026 tmp
= bsi_stmt (*bsi
);
3027 while (TREE_CODE (tmp
) == LABEL_EXPR
)
3030 if (bsi_end_p (*bsi
))
3032 tmp
= bsi_stmt (*bsi
);
3035 if (bsi_end_p (*bsi
))
3037 *bsi
= bsi_last (dest
);
3044 /* If the source has one successor, the edge is not abnormal and
3045 the last statement does not end a basic block, insert there.
3046 Except for the entry block. */
3048 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3049 && single_succ_p (src
)
3050 && src
!= ENTRY_BLOCK_PTR
)
3052 *bsi
= bsi_last (src
);
3053 if (bsi_end_p (*bsi
))
3056 tmp
= bsi_stmt (*bsi
);
3057 if (!stmt_ends_bb_p (tmp
))
3060 /* Insert code just before returning the value. We may need to decompose
3061 the return in the case it contains non-trivial operand. */
3062 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3064 tree op
= TREE_OPERAND (tmp
, 0);
3065 if (op
&& !is_gimple_val (op
))
3067 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3068 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3069 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3076 /* Otherwise, create a new basic block, and split this edge. */
3077 dest
= split_edge (e
);
3080 e
= single_pred_edge (dest
);
3085 /* This routine will commit all pending edge insertions, creating any new
3086 basic blocks which are necessary. */
3089 bsi_commit_edge_inserts (void)
3095 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
3098 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3099 bsi_commit_one_edge_insert (e
, NULL
);
3103 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3104 to this block, otherwise set it to NULL. */
3107 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3111 if (PENDING_STMT (e
))
3113 block_stmt_iterator bsi
;
3114 tree stmt
= PENDING_STMT (e
);
3116 PENDING_STMT (e
) = NULL_TREE
;
3118 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3119 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3121 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3126 /* Add STMT to the pending list of edge E. No actual insertion is
3127 made until a call to bsi_commit_edge_inserts () is made. */
3130 bsi_insert_on_edge (edge e
, tree stmt
)
3132 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3135 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3136 block has to be created, it is returned. */
3139 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3141 block_stmt_iterator bsi
;
3142 basic_block new_bb
= NULL
;
3144 gcc_assert (!PENDING_STMT (e
));
3146 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3147 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3149 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3154 /*---------------------------------------------------------------------------
3155 Tree specific functions for CFG manipulation
3156 ---------------------------------------------------------------------------*/
3158 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3161 reinstall_phi_args (edge new_edge
, edge old_edge
)
3165 if (!PENDING_STMT (old_edge
))
3168 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3170 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3172 tree result
= TREE_PURPOSE (var
);
3173 tree arg
= TREE_VALUE (var
);
3175 gcc_assert (result
== PHI_RESULT (phi
));
3177 add_phi_arg (phi
, arg
, new_edge
);
3180 PENDING_STMT (old_edge
) = NULL
;
3183 /* Returns the basic block after that the new basic block created
3184 by splitting edge EDGE_IN should be placed. Tries to keep the new block
3185 near its "logical" location. This is of most help to humans looking
3186 at debugging dumps. */
3189 split_edge_bb_loc (edge edge_in
)
3191 basic_block dest
= edge_in
->dest
;
3193 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3194 return edge_in
->src
;
3196 return dest
->prev_bb
;
3199 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3200 Abort on abnormal edges. */
3203 tree_split_edge (edge edge_in
)
3205 basic_block new_bb
, after_bb
, dest
, src
;
3208 /* Abnormal edges cannot be split. */
3209 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3212 dest
= edge_in
->dest
;
3214 after_bb
= split_edge_bb_loc (edge_in
);
3216 new_bb
= create_empty_bb (after_bb
);
3217 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3218 new_bb
->count
= edge_in
->count
;
3219 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3220 new_edge
->probability
= REG_BR_PROB_BASE
;
3221 new_edge
->count
= edge_in
->count
;
3223 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3225 reinstall_phi_args (new_edge
, e
);
3231 /* Return true when BB has label LABEL in it. */
3234 has_label_p (basic_block bb
, tree label
)
3236 block_stmt_iterator bsi
;
3238 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3240 tree stmt
= bsi_stmt (bsi
);
3242 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3244 if (LABEL_EXPR_LABEL (stmt
) == label
)
3251 /* Callback for walk_tree, check that all elements with address taken are
3252 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3253 inside a PHI node. */
3256 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3259 bool in_phi
= (data
!= NULL
);
3264 /* Check operand N for being valid GIMPLE and give error MSG if not. */
3265 #define CHECK_OP(N, MSG) \
3266 do { if (!is_gimple_val (TREE_OPERAND (t, N))) \
3267 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3269 switch (TREE_CODE (t
))
3272 if (SSA_NAME_IN_FREE_LIST (t
))
3274 error ("SSA name in freelist but still referenced");
3280 x
= fold (ASSERT_EXPR_COND (t
));
3281 if (x
== boolean_false_node
)
3283 error ("ASSERT_EXPR with an always-false condition");
3289 x
= TREE_OPERAND (t
, 0);
3290 if (TREE_CODE (x
) == BIT_FIELD_REF
3291 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3293 error ("GIMPLE register modified with BIT_FIELD_REF");
3302 bool old_side_effects
;
3305 bool new_side_effects
;
3307 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3308 dead PHIs that take the address of something. But if the PHI
3309 result is dead, the fact that it takes the address of anything
3310 is irrelevant. Because we can not tell from here if a PHI result
3311 is dead, we just skip this check for PHIs altogether. This means
3312 we may be missing "valid" checks, but what can you do?
3313 This was PR19217. */
3317 old_invariant
= TREE_INVARIANT (t
);
3318 old_constant
= TREE_CONSTANT (t
);
3319 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3321 recompute_tree_invariant_for_addr_expr (t
);
3322 new_invariant
= TREE_INVARIANT (t
);
3323 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3324 new_constant
= TREE_CONSTANT (t
);
3326 if (old_invariant
!= new_invariant
)
3328 error ("invariant not recomputed when ADDR_EXPR changed");
3332 if (old_constant
!= new_constant
)
3334 error ("constant not recomputed when ADDR_EXPR changed");
3337 if (old_side_effects
!= new_side_effects
)
3339 error ("side effects not recomputed when ADDR_EXPR changed");
3343 /* Skip any references (they will be checked when we recurse down the
3344 tree) and ensure that any variable used as a prefix is marked
3346 for (x
= TREE_OPERAND (t
, 0);
3347 handled_component_p (x
);
3348 x
= TREE_OPERAND (x
, 0))
3351 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3353 if (!TREE_ADDRESSABLE (x
))
3355 error ("address taken, but ADDRESSABLE bit not set");
3362 x
= COND_EXPR_COND (t
);
3363 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3365 error ("non-boolean used in condition");
3368 if (!is_gimple_condexpr (x
))
3370 error ("invalid conditional operand");
3377 case FIX_TRUNC_EXPR
:
3379 case FIX_FLOOR_EXPR
:
3380 case FIX_ROUND_EXPR
:
3385 case NON_LVALUE_EXPR
:
3386 case TRUTH_NOT_EXPR
:
3387 CHECK_OP (0, "invalid operand to unary operator");
3394 case ARRAY_RANGE_REF
:
3396 case VIEW_CONVERT_EXPR
:
3397 /* We have a nest of references. Verify that each of the operands
3398 that determine where to reference is either a constant or a variable,
3399 verify that the base is valid, and then show we've already checked
3401 while (handled_component_p (t
))
3403 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3404 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3405 else if (TREE_CODE (t
) == ARRAY_REF
3406 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3408 CHECK_OP (1, "invalid array index");
3409 if (TREE_OPERAND (t
, 2))
3410 CHECK_OP (2, "invalid array lower bound");
3411 if (TREE_OPERAND (t
, 3))
3412 CHECK_OP (3, "invalid array stride");
3414 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3416 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3417 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3420 t
= TREE_OPERAND (t
, 0);
3423 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3425 error ("invalid reference prefix");
3437 case UNORDERED_EXPR
:
3448 case TRUNC_DIV_EXPR
:
3450 case FLOOR_DIV_EXPR
:
3451 case ROUND_DIV_EXPR
:
3452 case TRUNC_MOD_EXPR
:
3454 case FLOOR_MOD_EXPR
:
3455 case ROUND_MOD_EXPR
:
3457 case EXACT_DIV_EXPR
:
3467 CHECK_OP (0, "invalid operand to binary operator");
3468 CHECK_OP (1, "invalid operand to binary operator");
3480 /* Verify STMT, return true if STMT is not in GIMPLE form.
3481 TODO: Implement type checking. */
3484 verify_stmt (tree stmt
, bool last_in_block
)
3488 if (OMP_DIRECTIVE_P (stmt
))
3490 /* OpenMP directives are validated by the FE and never operated
3491 on by the optimizers. Furthermore, OMP_FOR may contain
3492 non-gimple expressions when the main index variable has had
3493 its address taken. This does not affect the loop itself
3494 because the header of an OMP_FOR is merely used to determine
3495 how to setup the parallel iteration. */
3499 if (!is_gimple_stmt (stmt
))
3501 error ("is not a valid GIMPLE statement");
3505 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3508 debug_generic_stmt (addr
);
3512 /* If the statement is marked as part of an EH region, then it is
3513 expected that the statement could throw. Verify that when we
3514 have optimizations that simplify statements such that we prove
3515 that they cannot throw, that we update other data structures
3517 if (lookup_stmt_eh_region (stmt
) >= 0)
3519 if (!tree_could_throw_p (stmt
))
3521 error ("statement marked for throw, but doesn%'t");
3524 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3526 error ("statement marked for throw in middle of block");
3534 debug_generic_stmt (stmt
);
3539 /* Return true when the T can be shared. */
3542 tree_node_can_be_shared (tree t
)
3544 if (IS_TYPE_OR_DECL_P (t
)
3545 || is_gimple_min_invariant (t
)
3546 || TREE_CODE (t
) == SSA_NAME
3547 || t
== error_mark_node
3548 || TREE_CODE (t
) == IDENTIFIER_NODE
)
3551 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3554 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3555 && is_gimple_min_invariant (TREE_OPERAND (t
, 1)))
3556 || TREE_CODE (t
) == COMPONENT_REF
3557 || TREE_CODE (t
) == REALPART_EXPR
3558 || TREE_CODE (t
) == IMAGPART_EXPR
)
3559 t
= TREE_OPERAND (t
, 0);
3568 /* Called via walk_trees. Verify tree sharing. */
3571 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3573 htab_t htab
= (htab_t
) data
;
3576 if (tree_node_can_be_shared (*tp
))
3578 *walk_subtrees
= false;
3582 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3584 return (tree
) *slot
;
3591 /* Verify the GIMPLE statement chain. */
3597 block_stmt_iterator bsi
;
3602 timevar_push (TV_TREE_STMT_VERIFY
);
3603 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3610 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3612 int phi_num_args
= PHI_NUM_ARGS (phi
);
3614 if (bb_for_stmt (phi
) != bb
)
3616 error ("bb_for_stmt (phi) is set to a wrong basic block");
3620 for (i
= 0; i
< phi_num_args
; i
++)
3622 tree t
= PHI_ARG_DEF (phi
, i
);
3625 /* Addressable variables do have SSA_NAMEs but they
3626 are not considered gimple values. */
3627 if (TREE_CODE (t
) != SSA_NAME
3628 && TREE_CODE (t
) != FUNCTION_DECL
3629 && !is_gimple_val (t
))
3631 error ("PHI def is not a GIMPLE value");
3632 debug_generic_stmt (phi
);
3633 debug_generic_stmt (t
);
3637 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3640 debug_generic_stmt (addr
);
3644 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3647 error ("incorrect sharing of tree nodes");
3648 debug_generic_stmt (phi
);
3649 debug_generic_stmt (addr
);
3655 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3657 tree stmt
= bsi_stmt (bsi
);
3659 if (bb_for_stmt (stmt
) != bb
)
3661 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3666 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3667 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3670 error ("incorrect sharing of tree nodes");
3671 debug_generic_stmt (stmt
);
3672 debug_generic_stmt (addr
);
3679 internal_error ("verify_stmts failed");
3682 timevar_pop (TV_TREE_STMT_VERIFY
);
3686 /* Verifies that the flow information is OK. */
3689 tree_verify_flow_info (void)
3693 block_stmt_iterator bsi
;
3698 if (ENTRY_BLOCK_PTR
->stmt_list
)
3700 error ("ENTRY_BLOCK has a statement list associated with it");
3704 if (EXIT_BLOCK_PTR
->stmt_list
)
3706 error ("EXIT_BLOCK has a statement list associated with it");
3710 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3711 if (e
->flags
& EDGE_FALLTHRU
)
3713 error ("fallthru to exit from bb %d", e
->src
->index
);
3719 bool found_ctrl_stmt
= false;
3723 /* Skip labels on the start of basic block. */
3724 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3726 tree prev_stmt
= stmt
;
3728 stmt
= bsi_stmt (bsi
);
3730 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3733 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3735 error ("nonlocal label ");
3736 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3737 fprintf (stderr
, " is not first in a sequence of labels in bb %d",
3742 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3745 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3746 fprintf (stderr
, " to block does not match in bb %d",
3751 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3752 != current_function_decl
)
3755 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3756 fprintf (stderr
, " has incorrect context in bb %d",
3762 /* Verify that body of basic block BB is free of control flow. */
3763 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3765 tree stmt
= bsi_stmt (bsi
);
3767 if (found_ctrl_stmt
)
3769 error ("control flow in the middle of basic block %d",
3774 if (stmt_ends_bb_p (stmt
))
3775 found_ctrl_stmt
= true;
3777 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3780 print_generic_expr (stderr
, LABEL_EXPR_LABEL (stmt
), 0);
3781 fprintf (stderr
, " in the middle of basic block %d", bb
->index
);
3786 bsi
= bsi_last (bb
);
3787 if (bsi_end_p (bsi
))
3790 stmt
= bsi_stmt (bsi
);
3792 err
|= verify_eh_edges (stmt
);
3794 if (is_ctrl_stmt (stmt
))
3796 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3797 if (e
->flags
& EDGE_FALLTHRU
)
3799 error ("fallthru edge after a control statement in bb %d",
3805 switch (TREE_CODE (stmt
))
3811 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3812 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3814 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3818 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3820 if (!true_edge
|| !false_edge
3821 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3822 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3823 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3824 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3825 || EDGE_COUNT (bb
->succs
) >= 3)
3827 error ("wrong outgoing edge flags at end of bb %d",
3832 if (!has_label_p (true_edge
->dest
,
3833 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3835 error ("%<then%> label does not match edge at end of bb %d",
3840 if (!has_label_p (false_edge
->dest
,
3841 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3843 error ("%<else%> label does not match edge at end of bb %d",
3851 if (simple_goto_p (stmt
))
3853 error ("explicit goto at end of bb %d", bb
->index
);
3858 /* FIXME. We should double check that the labels in the
3859 destination blocks have their address taken. */
3860 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3861 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3862 | EDGE_FALSE_VALUE
))
3863 || !(e
->flags
& EDGE_ABNORMAL
))
3865 error ("wrong outgoing edge flags at end of bb %d",
3873 if (!single_succ_p (bb
)
3874 || (single_succ_edge (bb
)->flags
3875 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3876 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3878 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3881 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3883 error ("return edge does not point to exit in bb %d",
3896 vec
= SWITCH_LABELS (stmt
);
3897 n
= TREE_VEC_LENGTH (vec
);
3899 /* Mark all the destination basic blocks. */
3900 for (i
= 0; i
< n
; ++i
)
3902 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3903 basic_block label_bb
= label_to_block (lab
);
3905 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3906 label_bb
->aux
= (void *)1;
3909 /* Verify that the case labels are sorted. */
3910 prev
= TREE_VEC_ELT (vec
, 0);
3911 for (i
= 1; i
< n
- 1; ++i
)
3913 tree c
= TREE_VEC_ELT (vec
, i
);
3916 error ("found default case not at end of case vector");
3920 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3922 error ("case labels not sorted: ");
3923 print_generic_expr (stderr
, prev
, 0);
3924 fprintf (stderr
," is greater than ");
3925 print_generic_expr (stderr
, c
, 0);
3926 fprintf (stderr
," but comes before it.\n");
3931 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3933 error ("no default case found at end of case vector");
3937 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3941 error ("extra outgoing edge %d->%d",
3942 bb
->index
, e
->dest
->index
);
3945 e
->dest
->aux
= (void *)2;
3946 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3947 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3949 error ("wrong outgoing edge flags at end of bb %d",
3955 /* Check that we have all of them. */
3956 for (i
= 0; i
< n
; ++i
)
3958 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3959 basic_block label_bb
= label_to_block (lab
);
3961 if (label_bb
->aux
!= (void *)2)
3963 error ("missing edge %i->%i",
3964 bb
->index
, label_bb
->index
);
3969 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3970 e
->dest
->aux
= (void *)0;
3977 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3978 verify_dominators (CDI_DOMINATORS
);
3984 /* Updates phi nodes after creating a forwarder block joined
3985 by edge FALLTHRU. */
3988 tree_make_forwarder_block (edge fallthru
)
3992 basic_block dummy
, bb
;
3993 tree phi
, new_phi
, var
;
3995 dummy
= fallthru
->src
;
3996 bb
= fallthru
->dest
;
3998 if (single_pred_p (bb
))
4001 /* If we redirected a branch we must create new phi nodes at the
4003 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
4005 var
= PHI_RESULT (phi
);
4006 new_phi
= create_phi_node (var
, bb
);
4007 SSA_NAME_DEF_STMT (var
) = new_phi
;
4008 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
4009 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
4012 /* Ensure that the PHI node chain is in the same order. */
4013 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
4015 /* Add the arguments we have stored on edges. */
4016 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4021 flush_pending_stmts (e
);
4026 /* Return a non-special label in the head of basic block BLOCK.
4027 Create one if it doesn't exist. */
4030 tree_block_label (basic_block bb
)
4032 block_stmt_iterator i
, s
= bsi_start (bb
);
4036 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4038 stmt
= bsi_stmt (i
);
4039 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4041 label
= LABEL_EXPR_LABEL (stmt
);
4042 if (!DECL_NONLOCAL (label
))
4045 bsi_move_before (&i
, &s
);
4050 label
= create_artificial_label ();
4051 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4052 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4057 /* Attempt to perform edge redirection by replacing a possibly complex
4058 jump instruction by a goto or by removing the jump completely.
4059 This can apply only if all edges now point to the same block. The
4060 parameters and return values are equivalent to
4061 redirect_edge_and_branch. */
4064 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4066 basic_block src
= e
->src
;
4067 block_stmt_iterator b
;
4070 /* We can replace or remove a complex jump only when we have exactly
4072 if (EDGE_COUNT (src
->succs
) != 2
4073 /* Verify that all targets will be TARGET. Specifically, the
4074 edge that is not E must also go to TARGET. */
4075 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4081 stmt
= bsi_stmt (b
);
4083 if (TREE_CODE (stmt
) == COND_EXPR
4084 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4086 bsi_remove (&b
, true);
4087 e
= ssa_redirect_edge (e
, target
);
4088 e
->flags
= EDGE_FALLTHRU
;
4096 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4097 edge representing the redirected branch. */
4100 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4102 basic_block bb
= e
->src
;
4103 block_stmt_iterator bsi
;
4107 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4110 if (e
->src
!= ENTRY_BLOCK_PTR
4111 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4114 if (e
->dest
== dest
)
4117 label
= tree_block_label (dest
);
4119 bsi
= bsi_last (bb
);
4120 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4122 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4125 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4126 ? COND_EXPR_THEN (stmt
)
4127 : COND_EXPR_ELSE (stmt
));
4128 GOTO_DESTINATION (stmt
) = label
;
4132 /* No non-abnormal edges should lead from a non-simple goto, and
4133 simple ones should be represented implicitly. */
4138 tree cases
= get_cases_for_edge (e
, stmt
);
4140 /* If we have a list of cases associated with E, then use it
4141 as it's a lot faster than walking the entire case vector. */
4144 edge e2
= find_edge (e
->src
, dest
);
4151 CASE_LABEL (cases
) = label
;
4152 cases
= TREE_CHAIN (cases
);
4155 /* If there was already an edge in the CFG, then we need
4156 to move all the cases associated with E to E2. */
4159 tree cases2
= get_cases_for_edge (e2
, stmt
);
4161 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4162 TREE_CHAIN (cases2
) = first
;
4167 tree vec
= SWITCH_LABELS (stmt
);
4168 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4170 for (i
= 0; i
< n
; i
++)
4172 tree elt
= TREE_VEC_ELT (vec
, i
);
4174 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4175 CASE_LABEL (elt
) = label
;
4183 bsi_remove (&bsi
, true);
4184 e
->flags
|= EDGE_FALLTHRU
;
4188 /* Otherwise it must be a fallthru edge, and we don't need to
4189 do anything besides redirecting it. */
4190 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4194 /* Update/insert PHI nodes as necessary. */
4196 /* Now update the edges in the CFG. */
4197 e
= ssa_redirect_edge (e
, dest
);
4203 /* Simple wrapper, as we can always redirect fallthru edges. */
4206 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4208 e
= tree_redirect_edge_and_branch (e
, dest
);
4215 /* Splits basic block BB after statement STMT (but at least after the
4216 labels). If STMT is NULL, BB is split just after the labels. */
4219 tree_split_block (basic_block bb
, void *stmt
)
4221 block_stmt_iterator bsi
, bsi_tgt
;
4227 new_bb
= create_empty_bb (bb
);
4229 /* Redirect the outgoing edges. */
4230 new_bb
->succs
= bb
->succs
;
4232 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4235 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4238 /* Move everything from BSI to the new basic block. */
4239 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4241 act
= bsi_stmt (bsi
);
4242 if (TREE_CODE (act
) == LABEL_EXPR
)
4255 bsi_tgt
= bsi_start (new_bb
);
4256 while (!bsi_end_p (bsi
))
4258 act
= bsi_stmt (bsi
);
4259 bsi_remove (&bsi
, false);
4260 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4267 /* Moves basic block BB after block AFTER. */
4270 tree_move_block_after (basic_block bb
, basic_block after
)
4272 if (bb
->prev_bb
== after
)
4276 link_block (bb
, after
);
4282 /* Return true if basic_block can be duplicated. */
4285 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4291 /* Create a duplicate of the basic block BB. NOTE: This does not
4292 preserve SSA form. */
4295 tree_duplicate_bb (basic_block bb
)
4298 block_stmt_iterator bsi
, bsi_tgt
;
4301 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4303 /* Copy the PHI nodes. We ignore PHI node arguments here because
4304 the incoming edges have not been setup yet. */
4305 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4307 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4308 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4311 /* Keep the chain of PHI nodes in the same order so that they can be
4312 updated by ssa_redirect_edge. */
4313 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4315 bsi_tgt
= bsi_start (new_bb
);
4316 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4318 def_operand_p def_p
;
4319 ssa_op_iter op_iter
;
4323 stmt
= bsi_stmt (bsi
);
4324 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4327 /* Create a new copy of STMT and duplicate STMT's virtual
4329 copy
= unshare_expr (stmt
);
4330 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4331 copy_virtual_operands (copy
, stmt
);
4332 region
= lookup_stmt_eh_region (stmt
);
4334 add_stmt_to_eh_region (copy
, region
);
4336 /* Create new names for all the definitions created by COPY and
4337 add replacement mappings for each new name. */
4338 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4339 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4346 /* Basic block BB_COPY was created by code duplication. Add phi node
4347 arguments for edges going out of BB_COPY. The blocks that were
4348 duplicated have BB_DUPLICATED set. */
4351 add_phi_args_after_copy_bb (basic_block bb_copy
)
4353 basic_block bb
, dest
;
4356 tree phi
, phi_copy
, phi_next
, def
;
4358 bb
= get_bb_original (bb_copy
);
4360 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4362 if (!phi_nodes (e_copy
->dest
))
4365 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4366 dest
= get_bb_original (e_copy
->dest
);
4368 dest
= e_copy
->dest
;
4370 e
= find_edge (bb
, dest
);
4373 /* During loop unrolling the target of the latch edge is copied.
4374 In this case we are not looking for edge to dest, but to
4375 duplicated block whose original was dest. */
4376 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4377 if ((e
->dest
->flags
& BB_DUPLICATED
)
4378 && get_bb_original (e
->dest
) == dest
)
4381 gcc_assert (e
!= NULL
);
4384 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4386 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4388 phi_next
= PHI_CHAIN (phi
);
4389 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4390 add_phi_arg (phi_copy
, def
, e_copy
);
4395 /* Blocks in REGION_COPY array of length N_REGION were created by
4396 duplication of basic blocks. Add phi node arguments for edges
4397 going from these blocks. */
4400 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4404 for (i
= 0; i
< n_region
; i
++)
4405 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4407 for (i
= 0; i
< n_region
; i
++)
4408 add_phi_args_after_copy_bb (region_copy
[i
]);
4410 for (i
= 0; i
< n_region
; i
++)
4411 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4414 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4415 important exit edge EXIT. By important we mean that no SSA name defined
4416 inside region is live over the other exit edges of the region. All entry
4417 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4418 to the duplicate of the region. SSA form, dominance and loop information
4419 is updated. The new basic blocks are stored to REGION_COPY in the same
4420 order as they had in REGION, provided that REGION_COPY is not NULL.
4421 The function returns false if it is unable to copy the region,
4425 tree_duplicate_sese_region (edge entry
, edge exit
,
4426 basic_block
*region
, unsigned n_region
,
4427 basic_block
*region_copy
)
4430 bool free_region_copy
= false, copying_header
= false;
4431 struct loop
*loop
= entry
->dest
->loop_father
;
4435 int total_freq
= 0, entry_freq
= 0;
4436 gcov_type total_count
= 0, entry_count
= 0;
4438 if (!can_copy_bbs_p (region
, n_region
))
4441 /* Some sanity checking. Note that we do not check for all possible
4442 missuses of the functions. I.e. if you ask to copy something weird,
4443 it will work, but the state of structures probably will not be
4445 for (i
= 0; i
< n_region
; i
++)
4447 /* We do not handle subloops, i.e. all the blocks must belong to the
4449 if (region
[i
]->loop_father
!= loop
)
4452 if (region
[i
] != entry
->dest
4453 && region
[i
] == loop
->header
)
4459 /* In case the function is used for loop header copying (which is the primary
4460 use), ensure that EXIT and its copy will be new latch and entry edges. */
4461 if (loop
->header
== entry
->dest
)
4463 copying_header
= true;
4464 loop
->copy
= loop
->outer
;
4466 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4469 for (i
= 0; i
< n_region
; i
++)
4470 if (region
[i
] != exit
->src
4471 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4477 region_copy
= XNEWVEC (basic_block
, n_region
);
4478 free_region_copy
= true;
4481 gcc_assert (!need_ssa_update_p ());
4483 /* Record blocks outside the region that are dominated by something
4485 doms
= XNEWVEC (basic_block
, n_basic_blocks
);
4486 initialize_original_copy_tables ();
4488 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4490 if (entry
->dest
->count
)
4492 total_count
= entry
->dest
->count
;
4493 entry_count
= entry
->count
;
4494 /* Fix up corner cases, to avoid division by zero or creation of negative
4496 if (entry_count
> total_count
)
4497 entry_count
= total_count
;
4501 total_freq
= entry
->dest
->frequency
;
4502 entry_freq
= EDGE_FREQUENCY (entry
);
4503 /* Fix up corner cases, to avoid division by zero or creation of negative
4505 if (total_freq
== 0)
4507 else if (entry_freq
> total_freq
)
4508 entry_freq
= total_freq
;
4511 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
,
4512 split_edge_bb_loc (entry
));
4515 scale_bbs_frequencies_gcov_type (region
, n_region
,
4516 total_count
- entry_count
,
4518 scale_bbs_frequencies_gcov_type (region_copy
, n_region
, entry_count
,
4523 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4525 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4530 loop
->header
= exit
->dest
;
4531 loop
->latch
= exit
->src
;
4534 /* Redirect the entry and add the phi node arguments. */
4535 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4536 gcc_assert (redirected
!= NULL
);
4537 flush_pending_stmts (entry
);
4539 /* Concerning updating of dominators: We must recount dominators
4540 for entry block and its copy. Anything that is outside of the
4541 region, but was dominated by something inside needs recounting as
4543 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4544 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4545 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4548 /* Add the other PHI node arguments. */
4549 add_phi_args_after_copy (region_copy
, n_region
);
4551 /* Update the SSA web. */
4552 update_ssa (TODO_update_ssa
);
4554 if (free_region_copy
)
4557 free_original_copy_tables ();
4562 DEF_VEC_P(basic_block);
4563 DEF_VEC_ALLOC_P(basic_block,heap);
4566 /* Add all the blocks dominated by ENTRY to the array BBS_P. Stop
4567 adding blocks when the dominator traversal reaches EXIT. This
4568 function silently assumes that ENTRY strictly dominates EXIT. */
4571 gather_blocks_in_sese_region (basic_block entry
, basic_block exit
,
4572 VEC(basic_block
,heap
) **bbs_p
)
4576 for (son
= first_dom_son (CDI_DOMINATORS
, entry
);
4578 son
= next_dom_son (CDI_DOMINATORS
, son
))
4580 VEC_safe_push (basic_block
, heap
, *bbs_p
, son
);
4582 gather_blocks_in_sese_region (son
, exit
, bbs_p
);
4592 bitmap vars_to_remove
;
4596 /* Helper for move_block_to_fn. Set TREE_BLOCK in every expression
4597 contained in *TP and change the DECL_CONTEXT of every local
4598 variable referenced in *TP. */
4601 move_stmt_r (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
, void *data
)
4603 struct move_stmt_d
*p
= (struct move_stmt_d
*) data
;
4605 if (p
->block
&& IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (TREE_CODE (*tp
))))
4606 TREE_BLOCK (*tp
) = p
->block
;
4608 if (OMP_DIRECTIVE_P (*tp
))
4610 /* Do not remap variables inside OMP directives. Variables
4611 referenced in clauses and directive header belong to the
4612 parent function and should not be moved into the child
4614 p
->remap_decls_p
= false;
4617 if (p
->remap_decls_p
4619 && DECL_CONTEXT (*tp
) == p
->from_context
)
4621 DECL_CONTEXT (*tp
) = p
->to_context
;
4623 if (TREE_CODE (*tp
) == VAR_DECL
)
4625 struct function
*f
= DECL_STRUCT_FUNCTION (p
->to_context
);
4626 f
->unexpanded_var_list
= tree_cons (0, *tp
, f
->unexpanded_var_list
);
4628 /* Mark *TP to be removed from the original function,
4629 otherwise it will be given a DECL_RTL when the original
4630 function is expanded. */
4631 bitmap_set_bit (p
->vars_to_remove
, DECL_UID (*tp
));
4639 /* Move basic block BB from function CFUN to function DEST_FN. The
4640 block is moved out of the original linked list and placed after
4641 block AFTER in the new list. Also, the block is removed from the
4642 original array of blocks and placed in DEST_FN's array of blocks.
4643 If UPDATE_EDGE_COUNT_P is true, the edge counts on both CFGs is
4644 updated to reflect the moved edges.
4646 On exit, local variables that need to be removed from
4647 CFUN->UNEXPANDED_VAR_LIST will have been added to VARS_TO_REMOVE. */
4650 move_block_to_fn (struct function
*dest_cfun
, basic_block bb
,
4651 basic_block after
, bool update_edge_count_p
,
4652 bitmap vars_to_remove
)
4654 struct control_flow_graph
*cfg
;
4657 block_stmt_iterator si
;
4658 struct move_stmt_d d
;
4659 unsigned old_len
, new_len
;
4662 /* Link BB to the new linked list. */
4663 move_block_after (bb
, after
);
4665 /* Update the edge count in the corresponding flowgraphs. */
4666 if (update_edge_count_p
)
4667 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4669 cfun
->cfg
->x_n_edges
--;
4670 dest_cfun
->cfg
->x_n_edges
++;
4673 /* Remove BB from the original basic block array. */
4674 VEC_replace (basic_block
, cfun
->cfg
->x_basic_block_info
, bb
->index
, NULL
);
4675 cfun
->cfg
->x_n_basic_blocks
--;
4677 /* Grow DEST_CFUN's basic block array if needed. */
4678 cfg
= dest_cfun
->cfg
;
4679 cfg
->x_n_basic_blocks
++;
4680 if (bb
->index
> cfg
->x_last_basic_block
)
4681 cfg
->x_last_basic_block
= bb
->index
;
4683 old_len
= VEC_length (basic_block
, cfg
->x_basic_block_info
);
4684 if ((unsigned) cfg
->x_last_basic_block
>= old_len
)
4686 new_len
= cfg
->x_last_basic_block
+ (cfg
->x_last_basic_block
+ 3) / 4;
4687 VEC_safe_grow (basic_block
, gc
, cfg
->x_basic_block_info
, new_len
);
4688 addr
= VEC_address (basic_block
, cfg
->x_basic_block_info
);
4689 memset (&addr
[old_len
], 0, sizeof (basic_block
) * (new_len
- old_len
));
4692 VEC_replace (basic_block
, cfg
->x_basic_block_info
,
4693 cfg
->x_last_basic_block
, bb
);
4695 /* The statements in BB need to be associated with a new TREE_BLOCK.
4696 Labels need to be associated with a new label-to-block map. */
4697 memset (&d
, 0, sizeof (d
));
4698 d
.vars_to_remove
= vars_to_remove
;
4700 for (si
= bsi_start (bb
); !bsi_end_p (si
); bsi_next (&si
))
4702 tree stmt
= bsi_stmt (si
);
4704 d
.from_context
= cfun
->decl
;
4705 d
.to_context
= dest_cfun
->decl
;
4706 d
.remap_decls_p
= true;
4707 if (TREE_BLOCK (stmt
))
4708 d
.block
= DECL_INITIAL (dest_cfun
->decl
);
4710 walk_tree (&stmt
, move_stmt_r
, &d
, NULL
);
4712 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4714 tree label
= LABEL_EXPR_LABEL (stmt
);
4715 int uid
= LABEL_DECL_UID (label
);
4717 gcc_assert (uid
> -1);
4719 old_len
= VEC_length (basic_block
, cfg
->x_label_to_block_map
);
4720 if (old_len
<= (unsigned) uid
)
4722 new_len
= 3 * uid
/ 2;
4723 VEC_safe_grow (basic_block
, gc
, cfg
->x_label_to_block_map
,
4725 addr
= VEC_address (basic_block
, cfg
->x_label_to_block_map
);
4726 memset (&addr
[old_len
], 0,
4727 sizeof (basic_block
) * (new_len
- old_len
));
4730 VEC_replace (basic_block
, cfg
->x_label_to_block_map
, uid
, bb
);
4731 VEC_replace (basic_block
, cfun
->cfg
->x_label_to_block_map
, uid
, NULL
);
4733 gcc_assert (DECL_CONTEXT (label
) == dest_cfun
->decl
);
4735 if (uid
>= dest_cfun
->last_label_uid
)
4736 dest_cfun
->last_label_uid
= uid
+ 1;
4742 /* Move a single-entry, single-exit region delimited by ENTRY_BB and
4743 EXIT_BB to function DEST_CFUN. The whole region is replaced by a
4744 single basic block in the original CFG and the new basic block is
4745 returned. DEST_CFUN must not have a CFG yet.
4747 Note that the region need not be a pure SESE region. Blocks inside
4748 the region may contain calls to abort/exit. The only restriction
4749 is that ENTRY_BB should be the only entry point and it must
4752 All local variables referenced in the region are assumed to be in
4753 the corresponding BLOCK_VARS and unexpanded variable lists
4754 associated with DEST_CFUN. */
4757 move_sese_region_to_fn (struct function
*dest_cfun
, basic_block entry_bb
,
4758 basic_block exit_bb
)
4760 VEC(basic_block
,heap
) *bbs
;
4761 basic_block after
, bb
, *entry_pred
, *exit_succ
;
4762 struct function
*saved_cfun
;
4763 int *entry_flag
, *exit_flag
;
4764 unsigned i
, num_entry_edges
, num_exit_edges
;
4767 bitmap vars_to_remove
;
4771 /* Collect all the blocks in the region. Manually add ENTRY_BB
4772 because it won't be added by dfs_enumerate_from. */
4773 calculate_dominance_info (CDI_DOMINATORS
);
4775 /* If ENTRY does not strictly dominate EXIT, this cannot be an SESE
4777 gcc_assert (entry_bb
!= exit_bb
4778 && dominated_by_p (CDI_DOMINATORS
, exit_bb
, entry_bb
));
4781 VEC_safe_push (basic_block
, heap
, bbs
, entry_bb
);
4782 gather_blocks_in_sese_region (entry_bb
, exit_bb
, &bbs
);
4784 /* Detach ENTRY_BB and EXIT_BB from CFUN->CFG. We need to remember
4785 the predecessor edges to ENTRY_BB and the successor edges to
4786 EXIT_BB so that we can re-attach them to the new basic block that
4787 will replace the region. */
4788 num_entry_edges
= EDGE_COUNT (entry_bb
->preds
);
4789 entry_pred
= (basic_block
*) xcalloc (num_entry_edges
, sizeof (basic_block
));
4790 entry_flag
= (int *) xcalloc (num_entry_edges
, sizeof (int));
4792 for (ei
= ei_start (entry_bb
->preds
); (e
= ei_safe_edge (ei
)) != NULL
;)
4794 entry_flag
[i
] = e
->flags
;
4795 entry_pred
[i
++] = e
->src
;
4799 num_exit_edges
= EDGE_COUNT (exit_bb
->succs
);
4800 exit_succ
= (basic_block
*) xcalloc (num_exit_edges
, sizeof (basic_block
));
4801 exit_flag
= (int *) xcalloc (num_exit_edges
, sizeof (int));
4803 for (ei
= ei_start (exit_bb
->succs
); (e
= ei_safe_edge (ei
)) != NULL
;)
4805 exit_flag
[i
] = e
->flags
;
4806 exit_succ
[i
++] = e
->dest
;
4810 /* Switch context to the child function to initialize DEST_FN's CFG. */
4811 gcc_assert (dest_cfun
->cfg
== NULL
);
4813 init_empty_tree_cfg ();
4816 /* Move blocks from BBS into DEST_CFUN. */
4817 gcc_assert (VEC_length (basic_block
, bbs
) >= 2);
4818 after
= dest_cfun
->cfg
->x_entry_block_ptr
;
4819 vars_to_remove
= BITMAP_ALLOC (NULL
);
4820 for (i
= 0; VEC_iterate (basic_block
, bbs
, i
, bb
); i
++)
4822 /* No need to update edge counts on the last block. It has
4823 already been updated earlier when we detached the region from
4824 the original CFG. */
4825 move_block_to_fn (dest_cfun
, bb
, after
, bb
!= exit_bb
, vars_to_remove
);
4829 /* Remove the variables marked in VARS_TO_REMOVE from
4830 CFUN->UNEXPANDED_VAR_LIST. Otherwise, they will be given a
4831 DECL_RTL in the context of CFUN. */
4832 if (!bitmap_empty_p (vars_to_remove
))
4836 for (p
= &cfun
->unexpanded_var_list
; *p
; )
4838 tree var
= TREE_VALUE (*p
);
4839 if (bitmap_bit_p (vars_to_remove
, DECL_UID (var
)))
4841 *p
= TREE_CHAIN (*p
);
4845 p
= &TREE_CHAIN (*p
);
4849 BITMAP_FREE (vars_to_remove
);
4851 /* Rewire the entry and exit blocks. The successor to the entry
4852 block turns into the successor of DEST_FN's ENTRY_BLOCK_PTR in
4853 the child function. Similarly, the predecessor of DEST_FN's
4854 EXIT_BLOCK_PTR turns into the predecessor of EXIT_BLOCK_PTR. We
4855 need to switch CFUN between DEST_CFUN and SAVED_CFUN so that the
4856 various CFG manipulation function get to the right CFG.
4858 FIXME, this is silly. The CFG ought to become a parameter to
4861 make_edge (ENTRY_BLOCK_PTR
, entry_bb
, EDGE_FALLTHRU
);
4862 make_edge (exit_bb
, EXIT_BLOCK_PTR
, 0);
4865 /* Back in the original function, the SESE region has disappeared,
4866 create a new basic block in its place. */
4867 bb
= create_empty_bb (entry_pred
[0]);
4868 for (i
= 0; i
< num_entry_edges
; i
++)
4869 make_edge (entry_pred
[i
], bb
, entry_flag
[i
]);
4871 for (i
= 0; i
< num_exit_edges
; i
++)
4872 make_edge (bb
, exit_succ
[i
], exit_flag
[i
]);
4878 free_dominance_info (CDI_DOMINATORS
);
4879 free_dominance_info (CDI_POST_DOMINATORS
);
4880 VEC_free (basic_block
, heap
, bbs
);
4886 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4889 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4891 tree arg
, vars
, var
;
4892 bool ignore_topmost_bind
= false, any_var
= false;
4895 struct function
*saved_cfun
;
4897 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4899 arg
= DECL_ARGUMENTS (fn
);
4902 print_generic_expr (file
, arg
, dump_flags
);
4903 if (TREE_CHAIN (arg
))
4904 fprintf (file
, ", ");
4905 arg
= TREE_CHAIN (arg
);
4907 fprintf (file
, ")\n");
4909 if (flags
& TDF_DETAILS
)
4910 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4911 if (flags
& TDF_RAW
)
4913 dump_node (fn
, TDF_SLIM
| flags
, file
);
4917 /* Switch CFUN to point to FN. */
4919 cfun
= DECL_STRUCT_FUNCTION (fn
);
4921 /* When GIMPLE is lowered, the variables are no longer available in
4922 BIND_EXPRs, so display them separately. */
4923 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4925 ignore_topmost_bind
= true;
4927 fprintf (file
, "{\n");
4928 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4930 var
= TREE_VALUE (vars
);
4932 print_generic_decl (file
, var
, flags
);
4933 fprintf (file
, "\n");
4939 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4941 /* Make a CFG based dump. */
4942 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4943 if (!ignore_topmost_bind
)
4944 fprintf (file
, "{\n");
4946 if (any_var
&& n_basic_blocks
)
4947 fprintf (file
, "\n");
4950 dump_generic_bb (file
, bb
, 2, flags
);
4952 fprintf (file
, "}\n");
4953 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4959 /* Make a tree based dump. */
4960 chain
= DECL_SAVED_TREE (fn
);
4962 if (chain
&& TREE_CODE (chain
) == BIND_EXPR
)
4964 if (ignore_topmost_bind
)
4966 chain
= BIND_EXPR_BODY (chain
);
4974 if (!ignore_topmost_bind
)
4975 fprintf (file
, "{\n");
4980 fprintf (file
, "\n");
4982 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4983 if (ignore_topmost_bind
)
4984 fprintf (file
, "}\n");
4987 fprintf (file
, "\n\n");
4994 /* Dump FUNCTION_DECL FN to stderr using FLAGS (see TDF_* in tree.h) */
4997 debug_function (tree fn
, int flags
)
4999 dump_function_to_file (fn
, stderr
, flags
);
5003 /* Pretty print of the loops intermediate representation. */
5004 static void print_loop (FILE *, struct loop
*, int);
5005 static void print_pred_bbs (FILE *, basic_block bb
);
5006 static void print_succ_bbs (FILE *, basic_block bb
);
5009 /* Print on FILE the indexes for the predecessors of basic_block BB. */
5012 print_pred_bbs (FILE *file
, basic_block bb
)
5017 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5018 fprintf (file
, "bb_%d ", e
->src
->index
);
5022 /* Print on FILE the indexes for the successors of basic_block BB. */
5025 print_succ_bbs (FILE *file
, basic_block bb
)
5030 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5031 fprintf (file
, "bb_%d ", e
->dest
->index
);
5035 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5038 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5046 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5047 memset ((void *) s_indent
, ' ', (size_t) indent
);
5048 s_indent
[indent
] = '\0';
5050 /* Print the loop's header. */
5051 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5053 /* Print the loop's body. */
5054 fprintf (file
, "%s{\n", s_indent
);
5056 if (bb
->loop_father
== loop
)
5058 /* Print the basic_block's header. */
5059 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5060 print_pred_bbs (file
, bb
);
5061 fprintf (file
, "}, succs = {");
5062 print_succ_bbs (file
, bb
);
5063 fprintf (file
, "})\n");
5065 /* Print the basic_block's body. */
5066 fprintf (file
, "%s {\n", s_indent
);
5067 tree_dump_bb (bb
, file
, indent
+ 4);
5068 fprintf (file
, "%s }\n", s_indent
);
5071 print_loop (file
, loop
->inner
, indent
+ 2);
5072 fprintf (file
, "%s}\n", s_indent
);
5073 print_loop (file
, loop
->next
, indent
);
5077 /* Follow a CFG edge from the entry point of the program, and on entry
5078 of a loop, pretty print the loop structure on FILE. */
5081 print_loop_ir (FILE *file
)
5085 bb
= BASIC_BLOCK (NUM_FIXED_BLOCKS
);
5086 if (bb
&& bb
->loop_father
)
5087 print_loop (file
, bb
->loop_father
, 0);
5091 /* Debugging loops structure at tree level. */
5094 debug_loop_ir (void)
5096 print_loop_ir (stderr
);
5100 /* Return true if BB ends with a call, possibly followed by some
5101 instructions that must stay with the call. Return false,
5105 tree_block_ends_with_call_p (basic_block bb
)
5107 block_stmt_iterator bsi
= bsi_last (bb
);
5108 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5112 /* Return true if BB ends with a conditional branch. Return false,
5116 tree_block_ends_with_condjump_p (basic_block bb
)
5118 tree stmt
= last_stmt (bb
);
5119 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
5123 /* Return true if we need to add fake edge to exit at statement T.
5124 Helper function for tree_flow_call_edges_add. */
5127 need_fake_edge_p (tree t
)
5131 /* NORETURN and LONGJMP calls already have an edge to exit.
5132 CONST and PURE calls do not need one.
5133 We don't currently check for CONST and PURE here, although
5134 it would be a good idea, because those attributes are
5135 figured out from the RTL in mark_constant_function, and
5136 the counter incrementation code from -fprofile-arcs
5137 leads to different results from -fbranch-probabilities. */
5138 call
= get_call_expr_in (t
);
5140 && !(call_expr_flags (call
) & ECF_NORETURN
))
5143 if (TREE_CODE (t
) == ASM_EXPR
5144 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5151 /* Add fake edges to the function exit for any non constant and non
5152 noreturn calls, volatile inline assembly in the bitmap of blocks
5153 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5154 the number of blocks that were split.
5156 The goal is to expose cases in which entering a basic block does
5157 not imply that all subsequent instructions must be executed. */
5160 tree_flow_call_edges_add (sbitmap blocks
)
5163 int blocks_split
= 0;
5164 int last_bb
= last_basic_block
;
5165 bool check_last_block
= false;
5167 if (n_basic_blocks
== NUM_FIXED_BLOCKS
)
5171 check_last_block
= true;
5173 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5175 /* In the last basic block, before epilogue generation, there will be
5176 a fallthru edge to EXIT. Special care is required if the last insn
5177 of the last basic block is a call because make_edge folds duplicate
5178 edges, which would result in the fallthru edge also being marked
5179 fake, which would result in the fallthru edge being removed by
5180 remove_fake_edges, which would result in an invalid CFG.
5182 Moreover, we can't elide the outgoing fake edge, since the block
5183 profiler needs to take this into account in order to solve the minimal
5184 spanning tree in the case that the call doesn't return.
5186 Handle this by adding a dummy instruction in a new last basic block. */
5187 if (check_last_block
)
5189 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5190 block_stmt_iterator bsi
= bsi_last (bb
);
5192 if (!bsi_end_p (bsi
))
5195 if (t
&& need_fake_edge_p (t
))
5199 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5202 bsi_insert_on_edge (e
, build_empty_stmt ());
5203 bsi_commit_edge_inserts ();
5208 /* Now add fake edges to the function exit for any non constant
5209 calls since there is no way that we can determine if they will
5211 for (i
= 0; i
< last_bb
; i
++)
5213 basic_block bb
= BASIC_BLOCK (i
);
5214 block_stmt_iterator bsi
;
5215 tree stmt
, last_stmt
;
5220 if (blocks
&& !TEST_BIT (blocks
, i
))
5223 bsi
= bsi_last (bb
);
5224 if (!bsi_end_p (bsi
))
5226 last_stmt
= bsi_stmt (bsi
);
5229 stmt
= bsi_stmt (bsi
);
5230 if (need_fake_edge_p (stmt
))
5233 /* The handling above of the final block before the
5234 epilogue should be enough to verify that there is
5235 no edge to the exit block in CFG already.
5236 Calling make_edge in such case would cause us to
5237 mark that edge as fake and remove it later. */
5238 #ifdef ENABLE_CHECKING
5239 if (stmt
== last_stmt
)
5241 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5242 gcc_assert (e
== NULL
);
5246 /* Note that the following may create a new basic block
5247 and renumber the existing basic blocks. */
5248 if (stmt
!= last_stmt
)
5250 e
= split_block (bb
, stmt
);
5254 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5258 while (!bsi_end_p (bsi
));
5263 verify_flow_info ();
5265 return blocks_split
;
5269 tree_purge_dead_eh_edges (basic_block bb
)
5271 bool changed
= false;
5274 tree stmt
= last_stmt (bb
);
5276 if (stmt
&& tree_can_throw_internal (stmt
))
5279 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5281 if (e
->flags
& EDGE_EH
)
5290 /* Removal of dead EH edges might change dominators of not
5291 just immediate successors. E.g. when bb1 is changed so that
5292 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5293 eh edges purged by this function in:
5305 idom(bb5) must be recomputed. For now just free the dominance
5308 free_dominance_info (CDI_DOMINATORS
);
5314 tree_purge_all_dead_eh_edges (bitmap blocks
)
5316 bool changed
= false;
5320 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5322 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5328 /* This function is called whenever a new edge is created or
5332 tree_execute_on_growing_pred (edge e
)
5334 basic_block bb
= e
->dest
;
5337 reserve_phi_args_for_new_edge (bb
);
5340 /* This function is called immediately before edge E is removed from
5341 the edge vector E->dest->preds. */
5344 tree_execute_on_shrinking_pred (edge e
)
5346 if (phi_nodes (e
->dest
))
5347 remove_phi_args (e
);
5350 /*---------------------------------------------------------------------------
5351 Helper functions for Loop versioning
5352 ---------------------------------------------------------------------------*/
5354 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
5355 of 'first'. Both of them are dominated by 'new_head' basic block. When
5356 'new_head' was created by 'second's incoming edge it received phi arguments
5357 on the edge by split_edge(). Later, additional edge 'e' was created to
5358 connect 'new_head' and 'first'. Now this routine adds phi args on this
5359 additional edge 'e' that new_head to second edge received as part of edge
5364 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
5365 basic_block new_head
, edge e
)
5368 edge e2
= find_edge (new_head
, second
);
5370 /* Because NEW_HEAD has been created by splitting SECOND's incoming
5371 edge, we should always have an edge from NEW_HEAD to SECOND. */
5372 gcc_assert (e2
!= NULL
);
5374 /* Browse all 'second' basic block phi nodes and add phi args to
5375 edge 'e' for 'first' head. PHI args are always in correct order. */
5377 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
5379 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
5381 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
5382 add_phi_arg (phi1
, def
, e
);
5386 /* Adds a if else statement to COND_BB with condition COND_EXPR.
5387 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
5388 the destination of the ELSE part. */
5390 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
5391 basic_block cond_bb
, void *cond_e
)
5393 block_stmt_iterator bsi
;
5394 tree goto1
= NULL_TREE
;
5395 tree goto2
= NULL_TREE
;
5396 tree new_cond_expr
= NULL_TREE
;
5397 tree cond_expr
= (tree
) cond_e
;
5400 /* Build new conditional expr */
5401 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
5402 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
5403 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
5405 /* Add new cond in cond_bb. */
5406 bsi
= bsi_start (cond_bb
);
5407 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
5408 /* Adjust edges appropriately to connect new head with first head
5409 as well as second head. */
5410 e0
= single_succ_edge (cond_bb
);
5411 e0
->flags
&= ~EDGE_FALLTHRU
;
5412 e0
->flags
|= EDGE_FALSE_VALUE
;
5415 struct cfg_hooks tree_cfg_hooks
= {
5417 tree_verify_flow_info
,
5418 tree_dump_bb
, /* dump_bb */
5419 create_bb
, /* create_basic_block */
5420 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5421 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5422 remove_bb
, /* delete_basic_block */
5423 tree_split_block
, /* split_block */
5424 tree_move_block_after
, /* move_block_after */
5425 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5426 tree_merge_blocks
, /* merge_blocks */
5427 tree_predict_edge
, /* predict_edge */
5428 tree_predicted_by_p
, /* predicted_by_p */
5429 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5430 tree_duplicate_bb
, /* duplicate_block */
5431 tree_split_edge
, /* split_edge */
5432 tree_make_forwarder_block
, /* make_forward_block */
5433 NULL
, /* tidy_fallthru_edge */
5434 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5435 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5436 tree_flow_call_edges_add
, /* flow_call_edges_add */
5437 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5438 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5439 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
5440 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
5441 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
5442 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
5443 flush_pending_stmts
/* flush_pending_stmts */
5447 /* Split all critical edges. */
5450 split_critical_edges (void)
5456 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5457 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5458 mappings around the calls to split_edge. */
5459 start_recording_case_labels ();
5462 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5463 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5468 end_recording_case_labels ();
5471 struct tree_opt_pass pass_split_crit_edges
=
5473 "crited", /* name */
5475 split_critical_edges
, /* execute */
5478 0, /* static_pass_number */
5479 TV_TREE_SPLIT_EDGES
, /* tv_id */
5480 PROP_cfg
, /* properties required */
5481 PROP_no_crit_edges
, /* properties_provided */
5482 0, /* properties_destroyed */
5483 0, /* todo_flags_start */
5484 TODO_dump_func
, /* todo_flags_finish */
5489 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5490 a temporary, make sure and register it to be renamed if necessary,
5491 and finally return the temporary. Put the statements to compute
5492 EXP before the current statement in BSI. */
5495 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5497 tree t
, new_stmt
, orig_stmt
;
5499 if (is_gimple_val (exp
))
5502 t
= make_rename_temp (type
, NULL
);
5503 new_stmt
= build2 (MODIFY_EXPR
, type
, t
, exp
);
5505 orig_stmt
= bsi_stmt (*bsi
);
5506 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5507 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5509 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5514 /* Build a ternary operation and gimplify it. Emit code before BSI.
5515 Return the gimple_val holding the result. */
5518 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5519 tree type
, tree a
, tree b
, tree c
)
5523 ret
= fold_build3 (code
, type
, a
, b
, c
);
5526 return gimplify_val (bsi
, type
, ret
);
5529 /* Build a binary operation and gimplify it. Emit code before BSI.
5530 Return the gimple_val holding the result. */
5533 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5534 tree type
, tree a
, tree b
)
5538 ret
= fold_build2 (code
, type
, a
, b
);
5541 return gimplify_val (bsi
, type
, ret
);
5544 /* Build a unary operation and gimplify it. Emit code before BSI.
5545 Return the gimple_val holding the result. */
5548 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5553 ret
= fold_build1 (code
, type
, a
);
5556 return gimplify_val (bsi
, type
, ret
);
5561 /* Emit return warnings. */
5564 execute_warn_function_return (void)
5566 #ifdef USE_MAPPED_LOCATION
5567 source_location location
;
5575 /* If we have a path to EXIT, then we do return. */
5576 if (TREE_THIS_VOLATILE (cfun
->decl
)
5577 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5579 #ifdef USE_MAPPED_LOCATION
5580 location
= UNKNOWN_LOCATION
;
5584 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5586 last
= last_stmt (e
->src
);
5587 if (TREE_CODE (last
) == RETURN_EXPR
5588 #ifdef USE_MAPPED_LOCATION
5589 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5591 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5595 #ifdef USE_MAPPED_LOCATION
5596 if (location
== UNKNOWN_LOCATION
)
5597 location
= cfun
->function_end_locus
;
5598 warning (0, "%H%<noreturn%> function does return", &location
);
5601 locus
= &cfun
->function_end_locus
;
5602 warning (0, "%H%<noreturn%> function does return", locus
);
5606 /* If we see "return;" in some basic block, then we do reach the end
5607 without returning a value. */
5608 else if (warn_return_type
5609 && !TREE_NO_WARNING (cfun
->decl
)
5610 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5611 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5613 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5615 tree last
= last_stmt (e
->src
);
5616 if (TREE_CODE (last
) == RETURN_EXPR
5617 && TREE_OPERAND (last
, 0) == NULL
5618 && !TREE_NO_WARNING (last
))
5620 #ifdef USE_MAPPED_LOCATION
5621 location
= EXPR_LOCATION (last
);
5622 if (location
== UNKNOWN_LOCATION
)
5623 location
= cfun
->function_end_locus
;
5624 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5626 locus
= EXPR_LOCUS (last
);
5628 locus
= &cfun
->function_end_locus
;
5629 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5631 TREE_NO_WARNING (cfun
->decl
) = 1;
5639 /* Given a basic block B which ends with a conditional and has
5640 precisely two successors, determine which of the edges is taken if
5641 the conditional is true and which is taken if the conditional is
5642 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5645 extract_true_false_edges_from_block (basic_block b
,
5649 edge e
= EDGE_SUCC (b
, 0);
5651 if (e
->flags
& EDGE_TRUE_VALUE
)
5654 *false_edge
= EDGE_SUCC (b
, 1);
5659 *true_edge
= EDGE_SUCC (b
, 1);
5663 struct tree_opt_pass pass_warn_function_return
=
5667 execute_warn_function_return
, /* execute */
5670 0, /* static_pass_number */
5672 PROP_cfg
, /* properties_required */
5673 0, /* properties_provided */
5674 0, /* properties_destroyed */
5675 0, /* todo_flags_start */
5676 0, /* todo_flags_finish */
5680 /* Emit noreturn warnings. */
5683 execute_warn_function_noreturn (void)
5685 if (warn_missing_noreturn
5686 && !TREE_THIS_VOLATILE (cfun
->decl
)
5687 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5688 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5689 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5690 "for attribute %<noreturn%>",
5694 struct tree_opt_pass pass_warn_function_noreturn
=
5698 execute_warn_function_noreturn
, /* execute */
5701 0, /* static_pass_number */
5703 PROP_cfg
, /* properties_required */
5704 0, /* properties_provided */
5705 0, /* properties_destroyed */
5706 0, /* todo_flags_start */
5707 0, /* todo_flags_finish */