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
;
133 last_basic_block
= 0;
134 VARRAY_BB_INIT (basic_block_info
, initial_cfg_capacity
, "basic_block_info");
136 /* Build a mapping of labels to their associated blocks. */
137 VARRAY_BB_INIT (label_to_block_map
, initial_cfg_capacity
,
138 "label to block map");
140 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
141 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
144 /*---------------------------------------------------------------------------
146 ---------------------------------------------------------------------------*/
148 /* Entry point to the CFG builder for trees. TP points to the list of
149 statements to be added to the flowgraph. */
152 build_tree_cfg (tree
*tp
)
154 /* Register specific tree functions. */
155 tree_register_cfg_hooks ();
157 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
159 init_empty_tree_cfg ();
161 found_computed_goto
= 0;
164 /* Computed gotos are hell to deal with, especially if there are
165 lots of them with a large number of destinations. So we factor
166 them to a common computed goto location before we build the
167 edge list. After we convert back to normal form, we will un-factor
168 the computed gotos since factoring introduces an unwanted jump. */
169 if (found_computed_goto
)
170 factor_computed_gotos ();
172 /* Make sure there is always at least one block, even if it's empty. */
173 if (n_basic_blocks
== 0)
174 create_empty_bb (ENTRY_BLOCK_PTR
);
176 /* Adjust the size of the array. */
177 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
179 /* To speed up statement iterator walks, we first purge dead labels. */
180 cleanup_dead_labels ();
182 /* Group case nodes to reduce the number of edges.
183 We do this after cleaning up dead labels because otherwise we miss
184 a lot of obvious case merging opportunities. */
185 group_case_labels ();
187 /* Create the edges of the flowgraph. */
190 /* Debugging dumps. */
192 /* Write the flowgraph to a VCG file. */
194 int local_dump_flags
;
195 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
198 tree_cfg2vcg (dump_file
);
199 dump_end (TDI_vcg
, dump_file
);
203 #ifdef ENABLE_CHECKING
207 /* Dump a textual representation of the flowgraph. */
209 dump_tree_cfg (dump_file
, dump_flags
);
213 execute_build_cfg (void)
215 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
218 struct tree_opt_pass pass_build_cfg
=
222 execute_build_cfg
, /* execute */
225 0, /* static_pass_number */
226 TV_TREE_CFG
, /* tv_id */
227 PROP_gimple_leh
, /* properties_required */
228 PROP_cfg
, /* properties_provided */
229 0, /* properties_destroyed */
230 0, /* todo_flags_start */
231 TODO_verify_stmts
, /* todo_flags_finish */
235 /* Search the CFG for any computed gotos. If found, factor them to a
236 common computed goto site. Also record the location of that site so
237 that we can un-factor the gotos after we have converted back to
241 factor_computed_gotos (void)
244 tree factored_label_decl
= NULL
;
246 tree factored_computed_goto_label
= NULL
;
247 tree factored_computed_goto
= NULL
;
249 /* We know there are one or more computed gotos in this function.
250 Examine the last statement in each basic block to see if the block
251 ends with a computed goto. */
255 block_stmt_iterator bsi
= bsi_last (bb
);
260 last
= bsi_stmt (bsi
);
262 /* Ignore the computed goto we create when we factor the original
264 if (last
== factored_computed_goto
)
267 /* If the last statement is a computed goto, factor it. */
268 if (computed_goto_p (last
))
272 /* The first time we find a computed goto we need to create
273 the factored goto block and the variable each original
274 computed goto will use for their goto destination. */
275 if (! factored_computed_goto
)
277 basic_block new_bb
= create_empty_bb (bb
);
278 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
280 /* Create the destination of the factored goto. Each original
281 computed goto will put its desired destination into this
282 variable and jump to the label we create immediately
284 var
= create_tmp_var (ptr_type_node
, "gotovar");
286 /* Build a label for the new block which will contain the
287 factored computed goto. */
288 factored_label_decl
= create_artificial_label ();
289 factored_computed_goto_label
290 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
291 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
294 /* Build our new computed goto. */
295 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
296 bsi_insert_after (&new_bsi
, factored_computed_goto
,
300 /* Copy the original computed goto's destination into VAR. */
301 assignment
= build (MODIFY_EXPR
, ptr_type_node
,
302 var
, GOTO_DESTINATION (last
));
303 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
305 /* And re-vector the computed goto to the new destination. */
306 GOTO_DESTINATION (last
) = factored_label_decl
;
312 /* Build a flowgraph for the statement_list STMT_LIST. */
315 make_blocks (tree stmt_list
)
317 tree_stmt_iterator i
= tsi_start (stmt_list
);
319 bool start_new_block
= true;
320 bool first_stmt_of_list
= true;
321 basic_block bb
= ENTRY_BLOCK_PTR
;
323 while (!tsi_end_p (i
))
330 /* If the statement starts a new basic block or if we have determined
331 in a previous pass that we need to create a new block for STMT, do
333 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
335 if (!first_stmt_of_list
)
336 stmt_list
= tsi_split_statement_list_before (&i
);
337 bb
= create_basic_block (stmt_list
, NULL
, bb
);
338 start_new_block
= false;
341 /* Now add STMT to BB and create the subgraphs for special statement
343 set_bb_for_stmt (stmt
, bb
);
345 if (computed_goto_p (stmt
))
346 found_computed_goto
= true;
348 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
350 if (stmt_ends_bb_p (stmt
))
351 start_new_block
= true;
354 first_stmt_of_list
= false;
359 /* Create and return a new empty basic block after bb AFTER. */
362 create_bb (void *h
, void *e
, basic_block after
)
368 /* Create and initialize a new basic block. Since alloc_block uses
369 ggc_alloc_cleared to allocate a basic block, we do not have to
370 clear the newly allocated basic block here. */
373 bb
->index
= last_basic_block
;
375 bb
->stmt_list
= h
? h
: alloc_stmt_list ();
377 /* Add the new block to the linked list of blocks. */
378 link_block (bb
, after
);
380 /* Grow the basic block array if needed. */
381 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
383 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
384 VARRAY_GROW (basic_block_info
, new_size
);
387 /* Add the newly created block to the array. */
388 BASIC_BLOCK (last_basic_block
) = bb
;
397 /*---------------------------------------------------------------------------
399 ---------------------------------------------------------------------------*/
401 /* Fold COND_EXPR_COND of each COND_EXPR. */
404 fold_cond_expr_cond (void)
410 tree stmt
= last_stmt (bb
);
413 && TREE_CODE (stmt
) == COND_EXPR
)
415 tree cond
= fold (COND_EXPR_COND (stmt
));
416 if (integer_zerop (cond
))
417 COND_EXPR_COND (stmt
) = boolean_false_node
;
418 else if (integer_onep (cond
))
419 COND_EXPR_COND (stmt
) = boolean_true_node
;
424 /* Join all the blocks in the flowgraph. */
431 /* Create an edge from entry to the first block with executable
433 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (0), EDGE_FALLTHRU
);
435 /* Traverse the basic block array placing edges. */
438 tree first
= first_stmt (bb
);
439 tree last
= last_stmt (bb
);
443 /* Edges for statements that always alter flow control. */
444 if (is_ctrl_stmt (last
))
445 make_ctrl_stmt_edges (bb
);
447 /* Edges for statements that sometimes alter flow control. */
448 if (is_ctrl_altering_stmt (last
))
449 make_exit_edges (bb
);
452 /* Finally, if no edges were created above, this is a regular
453 basic block that only needs a fallthru edge. */
454 if (EDGE_COUNT (bb
->succs
) == 0)
455 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
458 /* We do not care about fake edges, so remove any that the CFG
459 builder inserted for completeness. */
460 remove_fake_exit_edges ();
462 /* Fold COND_EXPR_COND of each COND_EXPR. */
463 fold_cond_expr_cond ();
465 /* Clean up the graph and warn for unreachable code. */
470 /* Create edges for control statement at basic block BB. */
473 make_ctrl_stmt_edges (basic_block bb
)
475 tree last
= last_stmt (bb
);
478 switch (TREE_CODE (last
))
481 make_goto_expr_edges (bb
);
485 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
489 make_cond_expr_edges (bb
);
493 make_switch_expr_edges (bb
);
497 make_eh_edges (last
);
498 /* Yet another NORETURN hack. */
499 if (EDGE_COUNT (bb
->succs
) == 0)
500 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
509 /* Create exit edges for statements in block BB that alter the flow of
510 control. Statements that alter the control flow are 'goto', 'return'
511 and calls to non-returning functions. */
514 make_exit_edges (basic_block bb
)
516 tree last
= last_stmt (bb
), op
;
519 switch (TREE_CODE (last
))
524 /* If this function receives a nonlocal goto, then we need to
525 make edges from this call site to all the nonlocal goto
527 if (TREE_SIDE_EFFECTS (last
)
528 && current_function_has_nonlocal_label
)
529 make_goto_expr_edges (bb
);
531 /* If this statement has reachable exception handlers, then
532 create abnormal edges to them. */
533 make_eh_edges (last
);
535 /* Some calls are known not to return. For such calls we create
538 We really need to revamp how we build edges so that it's not
539 such a bloody pain to avoid creating edges for this case since
540 all we do is remove these edges when we're done building the
542 if (call_expr_flags (last
) & ECF_NORETURN
)
544 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
548 /* Don't forget the fall-thru edge. */
549 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
553 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
554 may have an abnormal edge. Search the RHS for this case and
555 create any required edges. */
556 op
= get_call_expr_in (last
);
557 if (op
&& TREE_SIDE_EFFECTS (op
)
558 && current_function_has_nonlocal_label
)
559 make_goto_expr_edges (bb
);
561 make_eh_edges (last
);
562 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
571 /* Create the edges for a COND_EXPR starting at block BB.
572 At this point, both clauses must contain only simple gotos. */
575 make_cond_expr_edges (basic_block bb
)
577 tree entry
= last_stmt (bb
);
578 basic_block then_bb
, else_bb
;
579 tree then_label
, else_label
;
582 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
584 /* Entry basic blocks for each component. */
585 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
586 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
587 then_bb
= label_to_block (then_label
);
588 else_bb
= label_to_block (else_label
);
590 make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
591 make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
594 /* Hashing routine for EDGE_TO_CASES. */
597 edge_to_cases_hash (const void *p
)
599 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
601 /* Hash on the edge itself (which is a pointer). */
602 return htab_hash_pointer (e
);
605 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
606 for equality is just a pointer comparison. */
609 edge_to_cases_eq (const void *p1
, const void *p2
)
611 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
612 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
617 /* Called for each element in the hash table (P) as we delete the
618 edge to cases hash table.
620 Clear all the TREE_CHAINs to prevent problems with copying of
621 SWITCH_EXPRs and structure sharing rules, then free the hash table
625 edge_to_cases_cleanup (void *p
)
627 struct edge_to_cases_elt
*elt
= p
;
630 for (t
= elt
->case_labels
; t
; t
= next
)
632 next
= TREE_CHAIN (t
);
633 TREE_CHAIN (t
) = NULL
;
638 /* Start recording information mapping edges to case labels. */
641 start_recording_case_labels (void)
643 gcc_assert (edge_to_cases
== NULL
);
645 edge_to_cases
= htab_create (37,
648 edge_to_cases_cleanup
);
651 /* Return nonzero if we are recording information for case labels. */
654 recording_case_labels_p (void)
656 return (edge_to_cases
!= NULL
);
659 /* Stop recording information mapping edges to case labels and
660 remove any information we have recorded. */
662 end_recording_case_labels (void)
664 htab_delete (edge_to_cases
);
665 edge_to_cases
= NULL
;
668 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
671 record_switch_edge (edge e
, tree case_label
)
673 struct edge_to_cases_elt
*elt
;
676 /* Build a hash table element so we can see if E is already
678 elt
= xmalloc (sizeof (struct edge_to_cases_elt
));
680 elt
->case_labels
= case_label
;
682 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
686 /* E was not in the hash table. Install E into the hash table. */
691 /* E was already in the hash table. Free ELT as we do not need it
695 /* Get the entry stored in the hash table. */
696 elt
= (struct edge_to_cases_elt
*) *slot
;
698 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
699 TREE_CHAIN (case_label
) = elt
->case_labels
;
700 elt
->case_labels
= case_label
;
704 /* If we are inside a {start,end}_recording_cases block, then return
705 a chain of CASE_LABEL_EXPRs from T which reference E.
707 Otherwise return NULL. */
710 get_cases_for_edge (edge e
, tree t
)
712 struct edge_to_cases_elt elt
, *elt_p
;
717 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
718 chains available. Return NULL so the caller can detect this case. */
719 if (!recording_case_labels_p ())
724 elt
.case_labels
= NULL
;
725 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
729 elt_p
= (struct edge_to_cases_elt
*)*slot
;
730 return elt_p
->case_labels
;
733 /* If we did not find E in the hash table, then this must be the first
734 time we have been queried for information about E & T. Add all the
735 elements from T to the hash table then perform the query again. */
737 vec
= SWITCH_LABELS (t
);
738 n
= TREE_VEC_LENGTH (vec
);
739 for (i
= 0; i
< n
; i
++)
741 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
742 basic_block label_bb
= label_to_block (lab
);
743 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
748 /* Create the edges for a SWITCH_EXPR starting at block BB.
749 At this point, the switch body has been lowered and the
750 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
753 make_switch_expr_edges (basic_block bb
)
755 tree entry
= last_stmt (bb
);
759 vec
= SWITCH_LABELS (entry
);
760 n
= TREE_VEC_LENGTH (vec
);
762 for (i
= 0; i
< n
; ++i
)
764 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
765 basic_block label_bb
= label_to_block (lab
);
766 make_edge (bb
, label_bb
, 0);
771 /* Return the basic block holding label DEST. */
774 label_to_block_fn (struct function
*ifun
, tree dest
)
776 int uid
= LABEL_DECL_UID (dest
);
778 /* We would die hard when faced by an undefined label. Emit a label to
779 the very first basic block. This will hopefully make even the dataflow
780 and undefined variable warnings quite right. */
781 if ((errorcount
|| sorrycount
) && uid
< 0)
783 block_stmt_iterator bsi
= bsi_start (BASIC_BLOCK (0));
786 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
787 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
788 uid
= LABEL_DECL_UID (dest
);
790 if (VARRAY_SIZE (ifun
->cfg
->x_label_to_block_map
) <= (unsigned int)uid
)
792 return VARRAY_BB (ifun
->cfg
->x_label_to_block_map
, uid
);
795 /* Create edges for a goto statement at block BB. */
798 make_goto_expr_edges (basic_block bb
)
801 basic_block target_bb
;
803 block_stmt_iterator last
= bsi_last (bb
);
805 goto_t
= bsi_stmt (last
);
807 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
808 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
809 from a nonlocal goto. */
810 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
814 tree dest
= GOTO_DESTINATION (goto_t
);
817 /* A GOTO to a local label creates normal edges. */
818 if (simple_goto_p (goto_t
))
820 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
821 #ifdef USE_MAPPED_LOCATION
822 e
->goto_locus
= EXPR_LOCATION (goto_t
);
824 e
->goto_locus
= EXPR_LOCUS (goto_t
);
830 /* Nothing more to do for nonlocal gotos. */
831 if (TREE_CODE (dest
) == LABEL_DECL
)
834 /* Computed gotos remain. */
837 /* Look for the block starting with the destination label. In the
838 case of a computed goto, make an edge to any label block we find
840 FOR_EACH_BB (target_bb
)
842 block_stmt_iterator bsi
;
844 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
846 tree target
= bsi_stmt (bsi
);
848 if (TREE_CODE (target
) != LABEL_EXPR
)
852 /* Computed GOTOs. Make an edge to every label block that has
853 been marked as a potential target for a computed goto. */
854 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
855 /* Nonlocal GOTO target. Make an edge to every label block
856 that has been marked as a potential target for a nonlocal
858 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
860 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
866 /* Degenerate case of computed goto with no labels. */
867 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
868 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
872 /*---------------------------------------------------------------------------
874 ---------------------------------------------------------------------------*/
876 /* Cleanup useless labels in basic blocks. This is something we wish
877 to do early because it allows us to group case labels before creating
878 the edges for the CFG, and it speeds up block statement iterators in
880 We only run this pass once, running it more than once is probably not
883 /* A map from basic block index to the leading label of that block. */
884 static tree
*label_for_bb
;
886 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
888 update_eh_label (struct eh_region
*region
)
890 tree old_label
= get_eh_region_tree_label (region
);
894 basic_block bb
= label_to_block (old_label
);
896 /* ??? After optimizing, there may be EH regions with labels
897 that have already been removed from the function body, so
898 there is no basic block for them. */
902 new_label
= label_for_bb
[bb
->index
];
903 set_eh_region_tree_label (region
, new_label
);
907 /* Given LABEL return the first label in the same basic block. */
909 main_block_label (tree label
)
911 basic_block bb
= label_to_block (label
);
913 /* label_to_block possibly inserted undefined label into the chain. */
914 if (!label_for_bb
[bb
->index
])
915 label_for_bb
[bb
->index
] = label
;
916 return label_for_bb
[bb
->index
];
919 /* Cleanup redundant labels. This is a three-step process:
920 1) Find the leading label for each block.
921 2) Redirect all references to labels to the leading labels.
922 3) Cleanup all useless labels. */
925 cleanup_dead_labels (void)
928 label_for_bb
= xcalloc (last_basic_block
, sizeof (tree
));
930 /* Find a suitable label for each block. We use the first user-defined
931 label if there is one, or otherwise just the first label we see. */
934 block_stmt_iterator i
;
936 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
938 tree label
, stmt
= bsi_stmt (i
);
940 if (TREE_CODE (stmt
) != LABEL_EXPR
)
943 label
= LABEL_EXPR_LABEL (stmt
);
945 /* If we have not yet seen a label for the current block,
946 remember this one and see if there are more labels. */
947 if (! label_for_bb
[bb
->index
])
949 label_for_bb
[bb
->index
] = label
;
953 /* If we did see a label for the current block already, but it
954 is an artificially created label, replace it if the current
955 label is a user defined label. */
956 if (! DECL_ARTIFICIAL (label
)
957 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
959 label_for_bb
[bb
->index
] = label
;
965 /* Now redirect all jumps/branches to the selected label.
966 First do so for each block ending in a control statement. */
969 tree stmt
= last_stmt (bb
);
973 switch (TREE_CODE (stmt
))
977 tree true_branch
, false_branch
;
979 true_branch
= COND_EXPR_THEN (stmt
);
980 false_branch
= COND_EXPR_ELSE (stmt
);
982 GOTO_DESTINATION (true_branch
)
983 = main_block_label (GOTO_DESTINATION (true_branch
));
984 GOTO_DESTINATION (false_branch
)
985 = main_block_label (GOTO_DESTINATION (false_branch
));
993 tree vec
= SWITCH_LABELS (stmt
);
994 size_t n
= TREE_VEC_LENGTH (vec
);
996 /* Replace all destination labels. */
997 for (i
= 0; i
< n
; ++i
)
999 tree elt
= TREE_VEC_ELT (vec
, i
);
1000 tree label
= main_block_label (CASE_LABEL (elt
));
1001 CASE_LABEL (elt
) = label
;
1006 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1007 remove them until after we've created the CFG edges. */
1009 if (! computed_goto_p (stmt
))
1011 GOTO_DESTINATION (stmt
)
1012 = main_block_label (GOTO_DESTINATION (stmt
));
1021 for_each_eh_region (update_eh_label
);
1023 /* Finally, purge dead labels. All user-defined labels and labels that
1024 can be the target of non-local gotos are preserved. */
1027 block_stmt_iterator i
;
1028 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1030 if (! label_for_this_bb
)
1033 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1035 tree label
, stmt
= bsi_stmt (i
);
1037 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1040 label
= LABEL_EXPR_LABEL (stmt
);
1042 if (label
== label_for_this_bb
1043 || ! DECL_ARTIFICIAL (label
)
1044 || DECL_NONLOCAL (label
))
1051 free (label_for_bb
);
1054 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1055 and scan the sorted vector of cases. Combine the ones jumping to the
1057 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1060 group_case_labels (void)
1066 tree stmt
= last_stmt (bb
);
1067 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1069 tree labels
= SWITCH_LABELS (stmt
);
1070 int old_size
= TREE_VEC_LENGTH (labels
);
1071 int i
, j
, new_size
= old_size
;
1072 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1075 /* The default label is always the last case in a switch
1076 statement after gimplification. */
1077 default_label
= CASE_LABEL (default_case
);
1079 /* Look for possible opportunities to merge cases.
1080 Ignore the last element of the label vector because it
1081 must be the default case. */
1083 while (i
< old_size
- 1)
1085 tree base_case
, base_label
, base_high
;
1086 base_case
= TREE_VEC_ELT (labels
, i
);
1088 gcc_assert (base_case
);
1089 base_label
= CASE_LABEL (base_case
);
1091 /* Discard cases that have the same destination as the
1093 if (base_label
== default_label
)
1095 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1101 base_high
= CASE_HIGH (base_case
) ?
1102 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1104 /* Try to merge case labels. Break out when we reach the end
1105 of the label vector or when we cannot merge the next case
1106 label with the current one. */
1107 while (i
< old_size
- 1)
1109 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1110 tree merge_label
= CASE_LABEL (merge_case
);
1111 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1112 integer_one_node
, 1);
1114 /* Merge the cases if they jump to the same place,
1115 and their ranges are consecutive. */
1116 if (merge_label
== base_label
1117 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1119 base_high
= CASE_HIGH (merge_case
) ?
1120 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1121 CASE_HIGH (base_case
) = base_high
;
1122 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1131 /* Compress the case labels in the label vector, and adjust the
1132 length of the vector. */
1133 for (i
= 0, j
= 0; i
< new_size
; i
++)
1135 while (! TREE_VEC_ELT (labels
, j
))
1137 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1139 TREE_VEC_LENGTH (labels
) = new_size
;
1144 /* Checks whether we can merge block B into block A. */
1147 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1150 block_stmt_iterator bsi
;
1153 if (!single_succ_p (a
))
1156 if (single_succ_edge (a
)->flags
& EDGE_ABNORMAL
)
1159 if (single_succ (a
) != b
)
1162 if (!single_pred_p (b
))
1165 if (b
== EXIT_BLOCK_PTR
)
1168 /* If A ends by a statement causing exceptions or something similar, we
1169 cannot merge the blocks. */
1170 stmt
= last_stmt (a
);
1171 if (stmt
&& stmt_ends_bb_p (stmt
))
1174 /* Do not allow a block with only a non-local label to be merged. */
1175 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1176 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1179 /* It must be possible to eliminate all phi nodes in B. If ssa form
1180 is not up-to-date, we cannot eliminate any phis. */
1181 phi
= phi_nodes (b
);
1184 if (need_ssa_update_p ())
1187 for (; phi
; phi
= PHI_CHAIN (phi
))
1188 if (!is_gimple_reg (PHI_RESULT (phi
))
1189 && !may_propagate_copy (PHI_RESULT (phi
), PHI_ARG_DEF (phi
, 0)))
1193 /* Do not remove user labels. */
1194 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1196 stmt
= bsi_stmt (bsi
);
1197 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1199 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1203 /* Protect the loop latches. */
1205 && b
->loop_father
->latch
== b
)
1211 /* Replaces all uses of NAME by VAL. */
1214 replace_uses_by (tree name
, tree val
)
1216 imm_use_iterator imm_iter
;
1221 VEC(tree
,heap
) *stmts
= VEC_alloc (tree
, heap
, 20);
1223 FOR_EACH_IMM_USE_SAFE (use
, imm_iter
, name
)
1225 stmt
= USE_STMT (use
);
1229 if (TREE_CODE (stmt
) == PHI_NODE
)
1231 e
= PHI_ARG_EDGE (stmt
, PHI_ARG_INDEX_FROM_USE (use
));
1232 if (e
->flags
& EDGE_ABNORMAL
)
1234 /* This can only occur for virtual operands, since
1235 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
1236 would prevent replacement. */
1237 gcc_assert (!is_gimple_reg (name
));
1238 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val
) = 1;
1242 VEC_safe_push (tree
, heap
, stmts
, stmt
);
1245 /* We do not update the statements in the loop above. Consider
1248 If we performed the update in the first loop, the statement
1249 would be rescanned after first occurrence of w is replaced,
1250 the new uses would be placed to the beginning of the list,
1251 and we would never process them. */
1252 for (i
= 0; VEC_iterate (tree
, stmts
, i
, stmt
); i
++)
1256 fold_stmt_inplace (stmt
);
1258 rhs
= get_rhs (stmt
);
1259 if (TREE_CODE (rhs
) == ADDR_EXPR
)
1260 recompute_tree_invarant_for_addr_expr (rhs
);
1265 VEC_free (tree
, heap
, stmts
);
1267 /* Also update the trees stored in loop structures. */
1272 for (i
= 0; i
< current_loops
->num
; i
++)
1274 loop
= current_loops
->parray
[i
];
1276 substitute_in_loop_info (loop
, name
, val
);
1281 /* Merge block B into block A. */
1284 tree_merge_blocks (basic_block a
, basic_block b
)
1286 block_stmt_iterator bsi
;
1287 tree_stmt_iterator last
;
1291 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1293 /* Remove the phi nodes. */
1295 for (phi
= phi_nodes (b
); phi
; phi
= phi_nodes (b
))
1297 tree def
= PHI_RESULT (phi
), use
= PHI_ARG_DEF (phi
, 0);
1300 if (!may_propagate_copy (def
, use
)
1301 /* Propagating pointers might cause the set of vops for statements
1302 to be changed, and thus require ssa form update. */
1303 || (is_gimple_reg (def
)
1304 && POINTER_TYPE_P (TREE_TYPE (def
))))
1306 gcc_assert (is_gimple_reg (def
));
1308 /* Note that just emitting the copies is fine -- there is no problem
1309 with ordering of phi nodes. This is because A is the single
1310 predecessor of B, therefore results of the phi nodes cannot
1311 appear as arguments of the phi nodes. */
1312 copy
= build2 (MODIFY_EXPR
, void_type_node
, def
, use
);
1313 bsi_insert_after (&bsi
, copy
, BSI_NEW_STMT
);
1314 SET_PHI_RESULT (phi
, NULL_TREE
);
1315 SSA_NAME_DEF_STMT (def
) = copy
;
1318 replace_uses_by (def
, use
);
1319 remove_phi_node (phi
, NULL
);
1322 /* Ensure that B follows A. */
1323 move_block_after (b
, a
);
1325 gcc_assert (single_succ_edge (a
)->flags
& EDGE_FALLTHRU
);
1326 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1328 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1329 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1331 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1333 tree label
= bsi_stmt (bsi
);
1336 /* Now that we can thread computed gotos, we might have
1337 a situation where we have a forced label in block B
1338 However, the label at the start of block B might still be
1339 used in other ways (think about the runtime checking for
1340 Fortran assigned gotos). So we can not just delete the
1341 label. Instead we move the label to the start of block A. */
1342 if (FORCED_LABEL (LABEL_EXPR_LABEL (label
)))
1344 block_stmt_iterator dest_bsi
= bsi_start (a
);
1345 bsi_insert_before (&dest_bsi
, label
, BSI_NEW_STMT
);
1350 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1355 /* Merge the chains. */
1356 last
= tsi_last (a
->stmt_list
);
1357 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1358 b
->stmt_list
= NULL
;
1362 /* Walk the function tree removing unnecessary statements.
1364 * Empty statement nodes are removed
1366 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1368 * Unnecessary COND_EXPRs are removed
1370 * Some unnecessary BIND_EXPRs are removed
1372 Clearly more work could be done. The trick is doing the analysis
1373 and removal fast enough to be a net improvement in compile times.
1375 Note that when we remove a control structure such as a COND_EXPR
1376 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1377 to ensure we eliminate all the useless code. */
1388 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1391 remove_useless_stmts_warn_notreached (tree stmt
)
1393 if (EXPR_HAS_LOCATION (stmt
))
1395 location_t loc
= EXPR_LOCATION (stmt
);
1396 if (LOCATION_LINE (loc
) > 0)
1398 warning (0, "%Hwill never be executed", &loc
);
1403 switch (TREE_CODE (stmt
))
1405 case STATEMENT_LIST
:
1407 tree_stmt_iterator i
;
1408 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1409 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1415 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1417 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1419 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1423 case TRY_FINALLY_EXPR
:
1424 case TRY_CATCH_EXPR
:
1425 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1427 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1432 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1433 case EH_FILTER_EXPR
:
1434 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1436 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1439 /* Not a live container. */
1447 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1449 tree then_clause
, else_clause
, cond
;
1450 bool save_has_label
, then_has_label
, else_has_label
;
1452 save_has_label
= data
->has_label
;
1453 data
->has_label
= false;
1454 data
->last_goto
= NULL
;
1456 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1458 then_has_label
= data
->has_label
;
1459 data
->has_label
= false;
1460 data
->last_goto
= NULL
;
1462 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1464 else_has_label
= data
->has_label
;
1465 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1467 then_clause
= COND_EXPR_THEN (*stmt_p
);
1468 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1469 cond
= fold (COND_EXPR_COND (*stmt_p
));
1471 /* If neither arm does anything at all, we can remove the whole IF. */
1472 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1474 *stmt_p
= build_empty_stmt ();
1475 data
->repeat
= true;
1478 /* If there are no reachable statements in an arm, then we can
1479 zap the entire conditional. */
1480 else if (integer_nonzerop (cond
) && !else_has_label
)
1482 if (warn_notreached
)
1483 remove_useless_stmts_warn_notreached (else_clause
);
1484 *stmt_p
= then_clause
;
1485 data
->repeat
= true;
1487 else if (integer_zerop (cond
) && !then_has_label
)
1489 if (warn_notreached
)
1490 remove_useless_stmts_warn_notreached (then_clause
);
1491 *stmt_p
= else_clause
;
1492 data
->repeat
= true;
1495 /* Check a couple of simple things on then/else with single stmts. */
1498 tree then_stmt
= expr_only (then_clause
);
1499 tree else_stmt
= expr_only (else_clause
);
1501 /* Notice branches to a common destination. */
1502 if (then_stmt
&& else_stmt
1503 && TREE_CODE (then_stmt
) == GOTO_EXPR
1504 && TREE_CODE (else_stmt
) == GOTO_EXPR
1505 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1507 *stmt_p
= then_stmt
;
1508 data
->repeat
= true;
1511 /* If the THEN/ELSE clause merely assigns a value to a variable or
1512 parameter which is already known to contain that value, then
1513 remove the useless THEN/ELSE clause. */
1514 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1517 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1518 && TREE_OPERAND (else_stmt
, 0) == cond
1519 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1520 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1522 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1523 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1524 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1525 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1527 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1528 ? then_stmt
: else_stmt
);
1529 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1530 ? &COND_EXPR_THEN (*stmt_p
)
1531 : &COND_EXPR_ELSE (*stmt_p
));
1534 && TREE_CODE (stmt
) == MODIFY_EXPR
1535 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1536 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1537 *location
= alloc_stmt_list ();
1541 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1542 would be re-introduced during lowering. */
1543 data
->last_goto
= NULL
;
1548 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1550 bool save_may_branch
, save_may_throw
;
1551 bool this_may_branch
, this_may_throw
;
1553 /* Collect may_branch and may_throw information for the body only. */
1554 save_may_branch
= data
->may_branch
;
1555 save_may_throw
= data
->may_throw
;
1556 data
->may_branch
= false;
1557 data
->may_throw
= false;
1558 data
->last_goto
= NULL
;
1560 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1562 this_may_branch
= data
->may_branch
;
1563 this_may_throw
= data
->may_throw
;
1564 data
->may_branch
|= save_may_branch
;
1565 data
->may_throw
|= save_may_throw
;
1566 data
->last_goto
= NULL
;
1568 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1570 /* If the body is empty, then we can emit the FINALLY block without
1571 the enclosing TRY_FINALLY_EXPR. */
1572 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1574 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1575 data
->repeat
= true;
1578 /* If the handler is empty, then we can emit the TRY block without
1579 the enclosing TRY_FINALLY_EXPR. */
1580 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1582 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1583 data
->repeat
= true;
1586 /* If the body neither throws, nor branches, then we can safely
1587 string the TRY and FINALLY blocks together. */
1588 else if (!this_may_branch
&& !this_may_throw
)
1590 tree stmt
= *stmt_p
;
1591 *stmt_p
= TREE_OPERAND (stmt
, 0);
1592 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1593 data
->repeat
= true;
1599 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1601 bool save_may_throw
, this_may_throw
;
1602 tree_stmt_iterator i
;
1605 /* Collect may_throw information for the body only. */
1606 save_may_throw
= data
->may_throw
;
1607 data
->may_throw
= false;
1608 data
->last_goto
= NULL
;
1610 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1612 this_may_throw
= data
->may_throw
;
1613 data
->may_throw
= save_may_throw
;
1615 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1616 if (!this_may_throw
)
1618 if (warn_notreached
)
1619 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1620 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1621 data
->repeat
= true;
1625 /* Process the catch clause specially. We may be able to tell that
1626 no exceptions propagate past this point. */
1628 this_may_throw
= true;
1629 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1630 stmt
= tsi_stmt (i
);
1631 data
->last_goto
= NULL
;
1633 switch (TREE_CODE (stmt
))
1636 for (; !tsi_end_p (i
); tsi_next (&i
))
1638 stmt
= tsi_stmt (i
);
1639 /* If we catch all exceptions, then the body does not
1640 propagate exceptions past this point. */
1641 if (CATCH_TYPES (stmt
) == NULL
)
1642 this_may_throw
= false;
1643 data
->last_goto
= NULL
;
1644 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1648 case EH_FILTER_EXPR
:
1649 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1650 this_may_throw
= false;
1651 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1652 this_may_throw
= false;
1653 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1657 /* Otherwise this is a cleanup. */
1658 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1660 /* If the cleanup is empty, then we can emit the TRY block without
1661 the enclosing TRY_CATCH_EXPR. */
1662 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1664 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1665 data
->repeat
= true;
1669 data
->may_throw
|= this_may_throw
;
1674 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1678 /* First remove anything underneath the BIND_EXPR. */
1679 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1681 /* If the BIND_EXPR has no variables, then we can pull everything
1682 up one level and remove the BIND_EXPR, unless this is the toplevel
1683 BIND_EXPR for the current function or an inlined function.
1685 When this situation occurs we will want to apply this
1686 optimization again. */
1687 block
= BIND_EXPR_BLOCK (*stmt_p
);
1688 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1689 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1691 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1692 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1695 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1696 data
->repeat
= true;
1702 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1704 tree dest
= GOTO_DESTINATION (*stmt_p
);
1706 data
->may_branch
= true;
1707 data
->last_goto
= NULL
;
1709 /* Record the last goto expr, so that we can delete it if unnecessary. */
1710 if (TREE_CODE (dest
) == LABEL_DECL
)
1711 data
->last_goto
= stmt_p
;
1716 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1718 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1720 data
->has_label
= true;
1722 /* We do want to jump across non-local label receiver code. */
1723 if (DECL_NONLOCAL (label
))
1724 data
->last_goto
= NULL
;
1726 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1728 *data
->last_goto
= build_empty_stmt ();
1729 data
->repeat
= true;
1732 /* ??? Add something here to delete unused labels. */
1736 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1737 decl. This allows us to eliminate redundant or useless
1738 calls to "const" functions.
1740 Gimplifier already does the same operation, but we may notice functions
1741 being const and pure once their calls has been gimplified, so we need
1742 to update the flag. */
1745 update_call_expr_flags (tree call
)
1747 tree decl
= get_callee_fndecl (call
);
1750 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1751 TREE_SIDE_EFFECTS (call
) = 0;
1752 if (TREE_NOTHROW (decl
))
1753 TREE_NOTHROW (call
) = 1;
1757 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1760 notice_special_calls (tree t
)
1762 int flags
= call_expr_flags (t
);
1764 if (flags
& ECF_MAY_BE_ALLOCA
)
1765 current_function_calls_alloca
= true;
1766 if (flags
& ECF_RETURNS_TWICE
)
1767 current_function_calls_setjmp
= true;
1771 /* Clear flags set by notice_special_calls. Used by dead code removal
1772 to update the flags. */
1775 clear_special_calls (void)
1777 current_function_calls_alloca
= false;
1778 current_function_calls_setjmp
= false;
1783 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1787 switch (TREE_CODE (t
))
1790 remove_useless_stmts_cond (tp
, data
);
1793 case TRY_FINALLY_EXPR
:
1794 remove_useless_stmts_tf (tp
, data
);
1797 case TRY_CATCH_EXPR
:
1798 remove_useless_stmts_tc (tp
, data
);
1802 remove_useless_stmts_bind (tp
, data
);
1806 remove_useless_stmts_goto (tp
, data
);
1810 remove_useless_stmts_label (tp
, data
);
1815 data
->last_goto
= NULL
;
1816 data
->may_branch
= true;
1821 data
->last_goto
= NULL
;
1822 notice_special_calls (t
);
1823 update_call_expr_flags (t
);
1824 if (tree_could_throw_p (t
))
1825 data
->may_throw
= true;
1829 data
->last_goto
= NULL
;
1831 op
= get_call_expr_in (t
);
1834 update_call_expr_flags (op
);
1835 notice_special_calls (op
);
1837 if (tree_could_throw_p (t
))
1838 data
->may_throw
= true;
1841 case STATEMENT_LIST
:
1843 tree_stmt_iterator i
= tsi_start (t
);
1844 while (!tsi_end_p (i
))
1847 if (IS_EMPTY_STMT (t
))
1853 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1856 if (TREE_CODE (t
) == STATEMENT_LIST
)
1858 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1868 data
->last_goto
= NULL
;
1872 data
->last_goto
= NULL
;
1878 remove_useless_stmts (void)
1880 struct rus_data data
;
1882 clear_special_calls ();
1886 memset (&data
, 0, sizeof (data
));
1887 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1889 while (data
.repeat
);
1893 struct tree_opt_pass pass_remove_useless_stmts
=
1895 "useless", /* name */
1897 remove_useless_stmts
, /* execute */
1900 0, /* static_pass_number */
1902 PROP_gimple_any
, /* properties_required */
1903 0, /* properties_provided */
1904 0, /* properties_destroyed */
1905 0, /* todo_flags_start */
1906 TODO_dump_func
, /* todo_flags_finish */
1910 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1913 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1917 /* Since this block is no longer reachable, we can just delete all
1918 of its PHI nodes. */
1919 phi
= phi_nodes (bb
);
1922 tree next
= PHI_CHAIN (phi
);
1923 remove_phi_node (phi
, NULL_TREE
);
1927 /* Remove edges to BB's successors. */
1928 while (EDGE_COUNT (bb
->succs
) > 0)
1929 remove_edge (EDGE_SUCC (bb
, 0));
1933 /* Remove statements of basic block BB. */
1936 remove_bb (basic_block bb
)
1938 block_stmt_iterator i
;
1939 #ifdef USE_MAPPED_LOCATION
1940 source_location loc
= UNKNOWN_LOCATION
;
1942 source_locus loc
= 0;
1947 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1948 if (dump_flags
& TDF_DETAILS
)
1950 dump_bb (bb
, dump_file
, 0);
1951 fprintf (dump_file
, "\n");
1955 /* If we remove the header or the latch of a loop, mark the loop for
1956 removal by setting its header and latch to NULL. */
1959 struct loop
*loop
= bb
->loop_father
;
1961 if (loop
->latch
== bb
1962 || loop
->header
== bb
)
1965 loop
->header
= NULL
;
1969 /* Remove all the instructions in the block. */
1970 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
1972 tree stmt
= bsi_stmt (i
);
1973 if (TREE_CODE (stmt
) == LABEL_EXPR
1974 && FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)))
1976 basic_block new_bb
= bb
->prev_bb
;
1977 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
1980 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
1984 release_defs (stmt
);
1989 /* Don't warn for removed gotos. Gotos are often removed due to
1990 jump threading, thus resulting in bogus warnings. Not great,
1991 since this way we lose warnings for gotos in the original
1992 program that are indeed unreachable. */
1993 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
1995 #ifdef USE_MAPPED_LOCATION
1996 if (EXPR_HAS_LOCATION (stmt
))
1997 loc
= EXPR_LOCATION (stmt
);
2000 t
= EXPR_LOCUS (stmt
);
2001 if (t
&& LOCATION_LINE (*t
) > 0)
2007 /* If requested, give a warning that the first statement in the
2008 block is unreachable. We walk statements backwards in the
2009 loop above, so the last statement we process is the first statement
2011 #ifdef USE_MAPPED_LOCATION
2012 if (loc
> BUILTINS_LOCATION
)
2013 warning (OPT_Wunreachable_code
, "%Hwill never be executed", &loc
);
2016 warning (OPT_Wunreachable_code
, "%Hwill never be executed", loc
);
2019 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2023 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2024 predicate VAL, return the edge that will be taken out of the block.
2025 If VAL does not match a unique edge, NULL is returned. */
2028 find_taken_edge (basic_block bb
, tree val
)
2032 stmt
= last_stmt (bb
);
2035 gcc_assert (is_ctrl_stmt (stmt
));
2038 if (! is_gimple_min_invariant (val
))
2041 if (TREE_CODE (stmt
) == COND_EXPR
)
2042 return find_taken_edge_cond_expr (bb
, val
);
2044 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2045 return find_taken_edge_switch_expr (bb
, val
);
2047 if (computed_goto_p (stmt
))
2048 return find_taken_edge_computed_goto (bb
, TREE_OPERAND( val
, 0));
2053 /* Given a constant value VAL and the entry block BB to a GOTO_EXPR
2054 statement, determine which of the outgoing edges will be taken out of the
2055 block. Return NULL if either edge may be taken. */
2058 find_taken_edge_computed_goto (basic_block bb
, tree val
)
2063 dest
= label_to_block (val
);
2066 e
= find_edge (bb
, dest
);
2067 gcc_assert (e
!= NULL
);
2073 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2074 statement, determine which of the two edges will be taken out of the
2075 block. Return NULL if either edge may be taken. */
2078 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2080 edge true_edge
, false_edge
;
2082 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2084 gcc_assert (TREE_CODE (val
) == INTEGER_CST
);
2085 return (zero_p (val
) ? false_edge
: true_edge
);
2088 /* Given an INTEGER_CST VAL and the entry block BB to a SWITCH_EXPR
2089 statement, determine which edge will be taken out of the block. Return
2090 NULL if any edge may be taken. */
2093 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2095 tree switch_expr
, taken_case
;
2096 basic_block dest_bb
;
2099 switch_expr
= last_stmt (bb
);
2100 taken_case
= find_case_label_for_value (switch_expr
, val
);
2101 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2103 e
= find_edge (bb
, dest_bb
);
2109 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2110 We can make optimal use here of the fact that the case labels are
2111 sorted: We can do a binary search for a case matching VAL. */
2114 find_case_label_for_value (tree switch_expr
, tree val
)
2116 tree vec
= SWITCH_LABELS (switch_expr
);
2117 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2118 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2120 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2122 size_t i
= (high
+ low
) / 2;
2123 tree t
= TREE_VEC_ELT (vec
, i
);
2126 /* Cache the result of comparing CASE_LOW and val. */
2127 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2134 if (CASE_HIGH (t
) == NULL
)
2136 /* A singe-valued case label. */
2142 /* A case range. We can only handle integer ranges. */
2143 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2148 return default_case
;
2154 /*---------------------------------------------------------------------------
2156 ---------------------------------------------------------------------------*/
2158 /* Dump tree-specific information of block BB to file OUTF. */
2161 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2163 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2167 /* Dump a basic block on stderr. */
2170 debug_tree_bb (basic_block bb
)
2172 dump_bb (bb
, stderr
, 0);
2176 /* Dump basic block with index N on stderr. */
2179 debug_tree_bb_n (int n
)
2181 debug_tree_bb (BASIC_BLOCK (n
));
2182 return BASIC_BLOCK (n
);
2186 /* Dump the CFG on stderr.
2188 FLAGS are the same used by the tree dumping functions
2189 (see TDF_* in tree.h). */
2192 debug_tree_cfg (int flags
)
2194 dump_tree_cfg (stderr
, flags
);
2198 /* Dump the program showing basic block boundaries on the given FILE.
2200 FLAGS are the same used by the tree dumping functions (see TDF_* in
2204 dump_tree_cfg (FILE *file
, int flags
)
2206 if (flags
& TDF_DETAILS
)
2208 const char *funcname
2209 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2212 fprintf (file
, ";; Function %s\n\n", funcname
);
2213 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2214 n_basic_blocks
, n_edges
, last_basic_block
);
2216 brief_dump_cfg (file
);
2217 fprintf (file
, "\n");
2220 if (flags
& TDF_STATS
)
2221 dump_cfg_stats (file
);
2223 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2227 /* Dump CFG statistics on FILE. */
2230 dump_cfg_stats (FILE *file
)
2232 static long max_num_merged_labels
= 0;
2233 unsigned long size
, total
= 0;
2236 const char * const fmt_str
= "%-30s%-13s%12s\n";
2237 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2238 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2239 const char *funcname
2240 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2243 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2245 fprintf (file
, "---------------------------------------------------------\n");
2246 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2247 fprintf (file
, fmt_str
, "", " instances ", "used ");
2248 fprintf (file
, "---------------------------------------------------------\n");
2250 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2252 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2253 SCALE (size
), LABEL (size
));
2257 num_edges
+= EDGE_COUNT (bb
->succs
);
2258 size
= num_edges
* sizeof (struct edge_def
);
2260 fprintf (file
, fmt_str_1
, "Edges", num_edges
, SCALE (size
), LABEL (size
));
2262 fprintf (file
, "---------------------------------------------------------\n");
2263 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2265 fprintf (file
, "---------------------------------------------------------\n");
2266 fprintf (file
, "\n");
2268 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2269 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2271 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2272 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2274 fprintf (file
, "\n");
2278 /* Dump CFG statistics on stderr. Keep extern so that it's always
2279 linked in the final executable. */
2282 debug_cfg_stats (void)
2284 dump_cfg_stats (stderr
);
2288 /* Dump the flowgraph to a .vcg FILE. */
2291 tree_cfg2vcg (FILE *file
)
2296 const char *funcname
2297 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2299 /* Write the file header. */
2300 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2301 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2302 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2304 /* Write blocks and edges. */
2305 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2307 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2310 if (e
->flags
& EDGE_FAKE
)
2311 fprintf (file
, " linestyle: dotted priority: 10");
2313 fprintf (file
, " linestyle: solid priority: 100");
2315 fprintf (file
, " }\n");
2321 enum tree_code head_code
, end_code
;
2322 const char *head_name
, *end_name
;
2325 tree first
= first_stmt (bb
);
2326 tree last
= last_stmt (bb
);
2330 head_code
= TREE_CODE (first
);
2331 head_name
= tree_code_name
[head_code
];
2332 head_line
= get_lineno (first
);
2335 head_name
= "no-statement";
2339 end_code
= TREE_CODE (last
);
2340 end_name
= tree_code_name
[end_code
];
2341 end_line
= get_lineno (last
);
2344 end_name
= "no-statement";
2346 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2347 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2350 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2352 if (e
->dest
== EXIT_BLOCK_PTR
)
2353 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2355 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2357 if (e
->flags
& EDGE_FAKE
)
2358 fprintf (file
, " priority: 10 linestyle: dotted");
2360 fprintf (file
, " priority: 100 linestyle: solid");
2362 fprintf (file
, " }\n");
2365 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2369 fputs ("}\n\n", file
);
2374 /*---------------------------------------------------------------------------
2375 Miscellaneous helpers
2376 ---------------------------------------------------------------------------*/
2378 /* Return true if T represents a stmt that always transfers control. */
2381 is_ctrl_stmt (tree t
)
2383 return (TREE_CODE (t
) == COND_EXPR
2384 || TREE_CODE (t
) == SWITCH_EXPR
2385 || TREE_CODE (t
) == GOTO_EXPR
2386 || TREE_CODE (t
) == RETURN_EXPR
2387 || TREE_CODE (t
) == RESX_EXPR
);
2391 /* Return true if T is a statement that may alter the flow of control
2392 (e.g., a call to a non-returning function). */
2395 is_ctrl_altering_stmt (tree t
)
2400 call
= get_call_expr_in (t
);
2403 /* A non-pure/const CALL_EXPR alters flow control if the current
2404 function has nonlocal labels. */
2405 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2408 /* A CALL_EXPR also alters control flow if it does not return. */
2409 if (call_expr_flags (call
) & ECF_NORETURN
)
2413 /* If a statement can throw, it alters control flow. */
2414 return tree_can_throw_internal (t
);
2418 /* Return true if T is a computed goto. */
2421 computed_goto_p (tree t
)
2423 return (TREE_CODE (t
) == GOTO_EXPR
2424 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2428 /* Checks whether EXPR is a simple local goto. */
2431 simple_goto_p (tree expr
)
2433 return (TREE_CODE (expr
) == GOTO_EXPR
2434 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2438 /* Return true if T should start a new basic block. PREV_T is the
2439 statement preceding T. It is used when T is a label or a case label.
2440 Labels should only start a new basic block if their previous statement
2441 wasn't a label. Otherwise, sequence of labels would generate
2442 unnecessary basic blocks that only contain a single label. */
2445 stmt_starts_bb_p (tree t
, tree prev_t
)
2450 /* LABEL_EXPRs start a new basic block only if the preceding
2451 statement wasn't a label of the same type. This prevents the
2452 creation of consecutive blocks that have nothing but a single
2454 if (TREE_CODE (t
) == LABEL_EXPR
)
2456 /* Nonlocal and computed GOTO targets always start a new block. */
2457 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2458 || FORCED_LABEL (LABEL_EXPR_LABEL (t
)))
2461 if (prev_t
&& TREE_CODE (prev_t
) == LABEL_EXPR
)
2463 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2466 cfg_stats
.num_merged_labels
++;
2477 /* Return true if T should end a basic block. */
2480 stmt_ends_bb_p (tree t
)
2482 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2486 /* Add gotos that used to be represented implicitly in the CFG. */
2489 disband_implicit_edges (void)
2492 block_stmt_iterator last
;
2499 last
= bsi_last (bb
);
2500 stmt
= last_stmt (bb
);
2502 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2504 /* Remove superfluous gotos from COND_EXPR branches. Moved
2505 from cfg_remove_useless_stmts here since it violates the
2506 invariants for tree--cfg correspondence and thus fits better
2507 here where we do it anyway. */
2508 e
= find_edge (bb
, bb
->next_bb
);
2511 if (e
->flags
& EDGE_TRUE_VALUE
)
2512 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2513 else if (e
->flags
& EDGE_FALSE_VALUE
)
2514 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2517 e
->flags
|= EDGE_FALLTHRU
;
2523 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2525 /* Remove the RETURN_EXPR if we may fall though to the exit
2527 gcc_assert (single_succ_p (bb
));
2528 gcc_assert (single_succ (bb
) == EXIT_BLOCK_PTR
);
2530 if (bb
->next_bb
== EXIT_BLOCK_PTR
2531 && !TREE_OPERAND (stmt
, 0))
2534 single_succ_edge (bb
)->flags
|= EDGE_FALLTHRU
;
2539 /* There can be no fallthru edge if the last statement is a control
2541 if (stmt
&& is_ctrl_stmt (stmt
))
2544 /* Find a fallthru edge and emit the goto if necessary. */
2545 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2546 if (e
->flags
& EDGE_FALLTHRU
)
2549 if (!e
|| e
->dest
== bb
->next_bb
)
2552 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2553 label
= tree_block_label (e
->dest
);
2555 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2556 #ifdef USE_MAPPED_LOCATION
2557 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2559 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2561 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2562 e
->flags
&= ~EDGE_FALLTHRU
;
2566 /* Remove block annotations and other datastructures. */
2569 delete_tree_cfg_annotations (void)
2571 label_to_block_map
= NULL
;
2575 /* Return the first statement in basic block BB. */
2578 first_stmt (basic_block bb
)
2580 block_stmt_iterator i
= bsi_start (bb
);
2581 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2585 /* Return the last statement in basic block BB. */
2588 last_stmt (basic_block bb
)
2590 block_stmt_iterator b
= bsi_last (bb
);
2591 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2595 /* Return a pointer to the last statement in block BB. */
2598 last_stmt_ptr (basic_block bb
)
2600 block_stmt_iterator last
= bsi_last (bb
);
2601 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2605 /* Return the last statement of an otherwise empty block. Return NULL
2606 if the block is totally empty, or if it contains more than one
2610 last_and_only_stmt (basic_block bb
)
2612 block_stmt_iterator i
= bsi_last (bb
);
2618 last
= bsi_stmt (i
);
2623 /* Empty statements should no longer appear in the instruction stream.
2624 Everything that might have appeared before should be deleted by
2625 remove_useless_stmts, and the optimizers should just bsi_remove
2626 instead of smashing with build_empty_stmt.
2628 Thus the only thing that should appear here in a block containing
2629 one executable statement is a label. */
2630 prev
= bsi_stmt (i
);
2631 if (TREE_CODE (prev
) == LABEL_EXPR
)
2638 /* Mark BB as the basic block holding statement T. */
2641 set_bb_for_stmt (tree t
, basic_block bb
)
2643 if (TREE_CODE (t
) == PHI_NODE
)
2645 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2647 tree_stmt_iterator i
;
2648 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2649 set_bb_for_stmt (tsi_stmt (i
), bb
);
2653 stmt_ann_t ann
= get_stmt_ann (t
);
2656 /* If the statement is a label, add the label to block-to-labels map
2657 so that we can speed up edge creation for GOTO_EXPRs. */
2658 if (TREE_CODE (t
) == LABEL_EXPR
)
2662 t
= LABEL_EXPR_LABEL (t
);
2663 uid
= LABEL_DECL_UID (t
);
2666 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2667 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2668 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2671 /* We're moving an existing label. Make sure that we've
2672 removed it from the old block. */
2673 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2674 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2679 /* Finds iterator for STMT. */
2681 extern block_stmt_iterator
2682 bsi_for_stmt (tree stmt
)
2684 block_stmt_iterator bsi
;
2686 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2687 if (bsi_stmt (bsi
) == stmt
)
2693 /* Mark statement T as modified, and update it. */
2695 update_modified_stmts (tree t
)
2697 if (TREE_CODE (t
) == STATEMENT_LIST
)
2699 tree_stmt_iterator i
;
2701 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2703 stmt
= tsi_stmt (i
);
2704 update_stmt_if_modified (stmt
);
2708 update_stmt_if_modified (t
);
2711 /* Insert statement (or statement list) T before the statement
2712 pointed-to by iterator I. M specifies how to update iterator I
2713 after insertion (see enum bsi_iterator_update). */
2716 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2718 set_bb_for_stmt (t
, i
->bb
);
2719 update_modified_stmts (t
);
2720 tsi_link_before (&i
->tsi
, t
, m
);
2724 /* Insert statement (or statement list) T after the statement
2725 pointed-to by iterator I. M specifies how to update iterator I
2726 after insertion (see enum bsi_iterator_update). */
2729 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2731 set_bb_for_stmt (t
, i
->bb
);
2732 update_modified_stmts (t
);
2733 tsi_link_after (&i
->tsi
, t
, m
);
2737 /* Remove the statement pointed to by iterator I. The iterator is updated
2738 to the next statement. */
2741 bsi_remove (block_stmt_iterator
*i
)
2743 tree t
= bsi_stmt (*i
);
2744 set_bb_for_stmt (t
, NULL
);
2745 delink_stmt_imm_use (t
);
2746 tsi_delink (&i
->tsi
);
2747 mark_stmt_modified (t
);
2751 /* Move the statement at FROM so it comes right after the statement at TO. */
2754 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2756 tree stmt
= bsi_stmt (*from
);
2758 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2762 /* Move the statement at FROM so it comes right before the statement at TO. */
2765 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2767 tree stmt
= bsi_stmt (*from
);
2769 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2773 /* Move the statement at FROM to the end of basic block BB. */
2776 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2778 block_stmt_iterator last
= bsi_last (bb
);
2780 /* Have to check bsi_end_p because it could be an empty block. */
2781 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2782 bsi_move_before (from
, &last
);
2784 bsi_move_after (from
, &last
);
2788 /* Replace the contents of the statement pointed to by iterator BSI
2789 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2790 information of the original statement is preserved. */
2793 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2796 tree orig_stmt
= bsi_stmt (*bsi
);
2798 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2799 set_bb_for_stmt (stmt
, bsi
->bb
);
2801 /* Preserve EH region information from the original statement, if
2802 requested by the caller. */
2803 if (preserve_eh_info
)
2805 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2807 add_stmt_to_eh_region (stmt
, eh_region
);
2810 delink_stmt_imm_use (orig_stmt
);
2811 *bsi_stmt_ptr (*bsi
) = stmt
;
2812 mark_stmt_modified (stmt
);
2813 update_modified_stmts (stmt
);
2817 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2818 is made to place the statement in an existing basic block, but
2819 sometimes that isn't possible. When it isn't possible, the edge is
2820 split and the statement is added to the new block.
2822 In all cases, the returned *BSI points to the correct location. The
2823 return value is true if insertion should be done after the location,
2824 or false if it should be done before the location. If new basic block
2825 has to be created, it is stored in *NEW_BB. */
2828 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2829 basic_block
*new_bb
)
2831 basic_block dest
, src
;
2837 /* If the destination has one predecessor which has no PHI nodes,
2838 insert there. Except for the exit block.
2840 The requirement for no PHI nodes could be relaxed. Basically we
2841 would have to examine the PHIs to prove that none of them used
2842 the value set by the statement we want to insert on E. That
2843 hardly seems worth the effort. */
2844 if (single_pred_p (dest
)
2845 && ! phi_nodes (dest
)
2846 && dest
!= EXIT_BLOCK_PTR
)
2848 *bsi
= bsi_start (dest
);
2849 if (bsi_end_p (*bsi
))
2852 /* Make sure we insert after any leading labels. */
2853 tmp
= bsi_stmt (*bsi
);
2854 while (TREE_CODE (tmp
) == LABEL_EXPR
)
2857 if (bsi_end_p (*bsi
))
2859 tmp
= bsi_stmt (*bsi
);
2862 if (bsi_end_p (*bsi
))
2864 *bsi
= bsi_last (dest
);
2871 /* If the source has one successor, the edge is not abnormal and
2872 the last statement does not end a basic block, insert there.
2873 Except for the entry block. */
2875 if ((e
->flags
& EDGE_ABNORMAL
) == 0
2876 && single_succ_p (src
)
2877 && src
!= ENTRY_BLOCK_PTR
)
2879 *bsi
= bsi_last (src
);
2880 if (bsi_end_p (*bsi
))
2883 tmp
= bsi_stmt (*bsi
);
2884 if (!stmt_ends_bb_p (tmp
))
2887 /* Insert code just before returning the value. We may need to decompose
2888 the return in the case it contains non-trivial operand. */
2889 if (TREE_CODE (tmp
) == RETURN_EXPR
)
2891 tree op
= TREE_OPERAND (tmp
, 0);
2892 if (!is_gimple_val (op
))
2894 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
2895 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
2896 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
2903 /* Otherwise, create a new basic block, and split this edge. */
2904 dest
= split_edge (e
);
2907 e
= single_pred_edge (dest
);
2912 /* This routine will commit all pending edge insertions, creating any new
2913 basic blocks which are necessary. */
2916 bsi_commit_edge_inserts (void)
2922 bsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR
), NULL
);
2925 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2926 bsi_commit_one_edge_insert (e
, NULL
);
2930 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
2931 to this block, otherwise set it to NULL. */
2934 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
2938 if (PENDING_STMT (e
))
2940 block_stmt_iterator bsi
;
2941 tree stmt
= PENDING_STMT (e
);
2943 PENDING_STMT (e
) = NULL_TREE
;
2945 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
2946 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
2948 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
2953 /* Add STMT to the pending list of edge E. No actual insertion is
2954 made until a call to bsi_commit_edge_inserts () is made. */
2957 bsi_insert_on_edge (edge e
, tree stmt
)
2959 append_to_statement_list (stmt
, &PENDING_STMT (e
));
2962 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
2963 block has to be created, it is returned. */
2966 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
2968 block_stmt_iterator bsi
;
2969 basic_block new_bb
= NULL
;
2971 gcc_assert (!PENDING_STMT (e
));
2973 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
2974 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
2976 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
2981 /*---------------------------------------------------------------------------
2982 Tree specific functions for CFG manipulation
2983 ---------------------------------------------------------------------------*/
2985 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
2988 reinstall_phi_args (edge new_edge
, edge old_edge
)
2992 if (!PENDING_STMT (old_edge
))
2995 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
2997 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
2999 tree result
= TREE_PURPOSE (var
);
3000 tree arg
= TREE_VALUE (var
);
3002 gcc_assert (result
== PHI_RESULT (phi
));
3004 add_phi_arg (phi
, arg
, new_edge
);
3007 PENDING_STMT (old_edge
) = NULL
;
3010 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3011 Abort on abnormal edges. */
3014 tree_split_edge (edge edge_in
)
3016 basic_block new_bb
, after_bb
, dest
, src
;
3019 /* Abnormal edges cannot be split. */
3020 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3023 dest
= edge_in
->dest
;
3025 /* Place the new block in the block list. Try to keep the new block
3026 near its "logical" location. This is of most help to humans looking
3027 at debugging dumps. */
3028 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3029 after_bb
= edge_in
->src
;
3031 after_bb
= dest
->prev_bb
;
3033 new_bb
= create_empty_bb (after_bb
);
3034 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3035 new_bb
->count
= edge_in
->count
;
3036 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3037 new_edge
->probability
= REG_BR_PROB_BASE
;
3038 new_edge
->count
= edge_in
->count
;
3040 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3042 reinstall_phi_args (new_edge
, e
);
3048 /* Return true when BB has label LABEL in it. */
3051 has_label_p (basic_block bb
, tree label
)
3053 block_stmt_iterator bsi
;
3055 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3057 tree stmt
= bsi_stmt (bsi
);
3059 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3061 if (LABEL_EXPR_LABEL (stmt
) == label
)
3068 /* Callback for walk_tree, check that all elements with address taken are
3069 properly noticed as such. The DATA is an int* that is 1 if TP was seen
3070 inside a PHI node. */
3073 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3076 bool in_phi
= (data
!= NULL
);
3081 /* Check operand N for being valid GIMPLE and give error MSG if not.
3082 We check for constants explicitly since they are not considered
3083 gimple invariants if they overflowed. */
3084 #define CHECK_OP(N, MSG) \
3085 do { if (!CONSTANT_CLASS_P (TREE_OPERAND (t, N)) \
3086 && !is_gimple_val (TREE_OPERAND (t, N))) \
3087 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3089 switch (TREE_CODE (t
))
3092 if (SSA_NAME_IN_FREE_LIST (t
))
3094 error ("SSA name in freelist but still referenced");
3100 x
= fold (ASSERT_EXPR_COND (t
));
3101 if (x
== boolean_false_node
)
3103 error ("ASSERT_EXPR with an always-false condition");
3109 x
= TREE_OPERAND (t
, 0);
3110 if (TREE_CODE (x
) == BIT_FIELD_REF
3111 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3113 error ("GIMPLE register modified with BIT_FIELD_REF");
3122 bool old_side_effects
;
3125 bool new_side_effects
;
3127 /* ??? tree-ssa-alias.c may have overlooked dead PHI nodes, missing
3128 dead PHIs that take the address of something. But if the PHI
3129 result is dead, the fact that it takes the address of anything
3130 is irrelevant. Because we can not tell from here if a PHI result
3131 is dead, we just skip this check for PHIs altogether. This means
3132 we may be missing "valid" checks, but what can you do?
3133 This was PR19217. */
3137 old_invariant
= TREE_INVARIANT (t
);
3138 old_constant
= TREE_CONSTANT (t
);
3139 old_side_effects
= TREE_SIDE_EFFECTS (t
);
3141 recompute_tree_invarant_for_addr_expr (t
);
3142 new_invariant
= TREE_INVARIANT (t
);
3143 new_side_effects
= TREE_SIDE_EFFECTS (t
);
3144 new_constant
= TREE_CONSTANT (t
);
3146 if (old_invariant
!= new_invariant
)
3148 error ("invariant not recomputed when ADDR_EXPR changed");
3152 if (old_constant
!= new_constant
)
3154 error ("constant not recomputed when ADDR_EXPR changed");
3157 if (old_side_effects
!= new_side_effects
)
3159 error ("side effects not recomputed when ADDR_EXPR changed");
3163 /* Skip any references (they will be checked when we recurse down the
3164 tree) and ensure that any variable used as a prefix is marked
3166 for (x
= TREE_OPERAND (t
, 0);
3167 handled_component_p (x
);
3168 x
= TREE_OPERAND (x
, 0))
3171 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3173 if (!TREE_ADDRESSABLE (x
))
3175 error ("address taken, but ADDRESSABLE bit not set");
3182 x
= COND_EXPR_COND (t
);
3183 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3185 error ("non-boolean used in condition");
3188 if (!is_gimple_condexpr (x
))
3190 error ("invalid conditional operand");
3197 case FIX_TRUNC_EXPR
:
3199 case FIX_FLOOR_EXPR
:
3200 case FIX_ROUND_EXPR
:
3205 case NON_LVALUE_EXPR
:
3206 case TRUTH_NOT_EXPR
:
3207 CHECK_OP (0, "invalid operand to unary operator");
3214 case ARRAY_RANGE_REF
:
3216 case VIEW_CONVERT_EXPR
:
3217 /* We have a nest of references. Verify that each of the operands
3218 that determine where to reference is either a constant or a variable,
3219 verify that the base is valid, and then show we've already checked
3221 while (handled_component_p (t
))
3223 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3224 CHECK_OP (2, "invalid COMPONENT_REF offset operator");
3225 else if (TREE_CODE (t
) == ARRAY_REF
3226 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3228 CHECK_OP (1, "invalid array index");
3229 if (TREE_OPERAND (t
, 2))
3230 CHECK_OP (2, "invalid array lower bound");
3231 if (TREE_OPERAND (t
, 3))
3232 CHECK_OP (3, "invalid array stride");
3234 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3236 CHECK_OP (1, "invalid operand to BIT_FIELD_REF");
3237 CHECK_OP (2, "invalid operand to BIT_FIELD_REF");
3240 t
= TREE_OPERAND (t
, 0);
3243 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3245 error ("invalid reference prefix");
3257 case UNORDERED_EXPR
:
3268 case TRUNC_DIV_EXPR
:
3270 case FLOOR_DIV_EXPR
:
3271 case ROUND_DIV_EXPR
:
3272 case TRUNC_MOD_EXPR
:
3274 case FLOOR_MOD_EXPR
:
3275 case ROUND_MOD_EXPR
:
3277 case EXACT_DIV_EXPR
:
3287 CHECK_OP (0, "invalid operand to binary operator");
3288 CHECK_OP (1, "invalid operand to binary operator");
3300 /* Verify STMT, return true if STMT is not in GIMPLE form.
3301 TODO: Implement type checking. */
3304 verify_stmt (tree stmt
, bool last_in_block
)
3308 if (!is_gimple_stmt (stmt
))
3310 error ("is not a valid GIMPLE statement");
3314 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3317 debug_generic_stmt (addr
);
3321 /* If the statement is marked as part of an EH region, then it is
3322 expected that the statement could throw. Verify that when we
3323 have optimizations that simplify statements such that we prove
3324 that they cannot throw, that we update other data structures
3326 if (lookup_stmt_eh_region (stmt
) >= 0)
3328 if (!tree_could_throw_p (stmt
))
3330 error ("statement marked for throw, but doesn%'t");
3333 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3335 error ("statement marked for throw in middle of block");
3343 debug_generic_stmt (stmt
);
3348 /* Return true when the T can be shared. */
3351 tree_node_can_be_shared (tree t
)
3353 if (IS_TYPE_OR_DECL_P (t
)
3354 /* We check for constants explicitly since they are not considered
3355 gimple invariants if they overflowed. */
3356 || CONSTANT_CLASS_P (t
)
3357 || is_gimple_min_invariant (t
)
3358 || TREE_CODE (t
) == SSA_NAME
3359 || t
== error_mark_node
)
3362 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3365 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3366 /* We check for constants explicitly since they are not considered
3367 gimple invariants if they overflowed. */
3368 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3369 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3370 || (TREE_CODE (t
) == COMPONENT_REF
3371 || TREE_CODE (t
) == REALPART_EXPR
3372 || TREE_CODE (t
) == IMAGPART_EXPR
))
3373 t
= TREE_OPERAND (t
, 0);
3382 /* Called via walk_trees. Verify tree sharing. */
3385 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3387 htab_t htab
= (htab_t
) data
;
3390 if (tree_node_can_be_shared (*tp
))
3392 *walk_subtrees
= false;
3396 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3405 /* Verify the GIMPLE statement chain. */
3411 block_stmt_iterator bsi
;
3416 timevar_push (TV_TREE_STMT_VERIFY
);
3417 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3424 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3426 int phi_num_args
= PHI_NUM_ARGS (phi
);
3428 if (bb_for_stmt (phi
) != bb
)
3430 error ("bb_for_stmt (phi) is set to a wrong basic block");
3434 for (i
= 0; i
< phi_num_args
; i
++)
3436 tree t
= PHI_ARG_DEF (phi
, i
);
3439 /* Addressable variables do have SSA_NAMEs but they
3440 are not considered gimple values. */
3441 if (TREE_CODE (t
) != SSA_NAME
3442 && TREE_CODE (t
) != FUNCTION_DECL
3443 && !is_gimple_val (t
))
3445 error ("PHI def is not a GIMPLE value");
3446 debug_generic_stmt (phi
);
3447 debug_generic_stmt (t
);
3451 addr
= walk_tree (&t
, verify_expr
, (void *) 1, NULL
);
3454 debug_generic_stmt (addr
);
3458 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3461 error ("incorrect sharing of tree nodes");
3462 debug_generic_stmt (phi
);
3463 debug_generic_stmt (addr
);
3469 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3471 tree stmt
= bsi_stmt (bsi
);
3473 if (bb_for_stmt (stmt
) != bb
)
3475 error ("bb_for_stmt (stmt) is set to a wrong basic block");
3480 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3481 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3484 error ("incorrect sharing of tree nodes");
3485 debug_generic_stmt (stmt
);
3486 debug_generic_stmt (addr
);
3493 internal_error ("verify_stmts failed");
3496 timevar_pop (TV_TREE_STMT_VERIFY
);
3500 /* Verifies that the flow information is OK. */
3503 tree_verify_flow_info (void)
3507 block_stmt_iterator bsi
;
3512 if (ENTRY_BLOCK_PTR
->stmt_list
)
3514 error ("ENTRY_BLOCK has a statement list associated with it");
3518 if (EXIT_BLOCK_PTR
->stmt_list
)
3520 error ("EXIT_BLOCK has a statement list associated with it");
3524 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3525 if (e
->flags
& EDGE_FALLTHRU
)
3527 error ("fallthru to exit from bb %d", e
->src
->index
);
3533 bool found_ctrl_stmt
= false;
3537 /* Skip labels on the start of basic block. */
3538 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3540 tree prev_stmt
= stmt
;
3542 stmt
= bsi_stmt (bsi
);
3544 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3547 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3549 error ("nonlocal label %s is not first "
3550 "in a sequence of labels in bb %d",
3551 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3556 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3558 error ("label %s to block does not match in bb %d",
3559 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3564 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3565 != current_function_decl
)
3567 error ("label %s has incorrect context in bb %d",
3568 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3574 /* Verify that body of basic block BB is free of control flow. */
3575 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3577 tree stmt
= bsi_stmt (bsi
);
3579 if (found_ctrl_stmt
)
3581 error ("control flow in the middle of basic block %d",
3586 if (stmt_ends_bb_p (stmt
))
3587 found_ctrl_stmt
= true;
3589 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3591 error ("label %s in the middle of basic block %d",
3592 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3597 bsi
= bsi_last (bb
);
3598 if (bsi_end_p (bsi
))
3601 stmt
= bsi_stmt (bsi
);
3603 err
|= verify_eh_edges (stmt
);
3605 if (is_ctrl_stmt (stmt
))
3607 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3608 if (e
->flags
& EDGE_FALLTHRU
)
3610 error ("fallthru edge after a control statement in bb %d",
3616 switch (TREE_CODE (stmt
))
3622 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3623 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3625 error ("structured COND_EXPR at the end of bb %d", bb
->index
);
3629 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3631 if (!true_edge
|| !false_edge
3632 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3633 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3634 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3635 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3636 || EDGE_COUNT (bb
->succs
) >= 3)
3638 error ("wrong outgoing edge flags at end of bb %d",
3643 if (!has_label_p (true_edge
->dest
,
3644 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3646 error ("%<then%> label does not match edge at end of bb %d",
3651 if (!has_label_p (false_edge
->dest
,
3652 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3654 error ("%<else%> label does not match edge at end of bb %d",
3662 if (simple_goto_p (stmt
))
3664 error ("explicit goto at end of bb %d", bb
->index
);
3669 /* FIXME. We should double check that the labels in the
3670 destination blocks have their address taken. */
3671 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3672 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3673 | EDGE_FALSE_VALUE
))
3674 || !(e
->flags
& EDGE_ABNORMAL
))
3676 error ("wrong outgoing edge flags at end of bb %d",
3684 if (!single_succ_p (bb
)
3685 || (single_succ_edge (bb
)->flags
3686 & (EDGE_FALLTHRU
| EDGE_ABNORMAL
3687 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3689 error ("wrong outgoing edge flags at end of bb %d", bb
->index
);
3692 if (single_succ (bb
) != EXIT_BLOCK_PTR
)
3694 error ("return edge does not point to exit in bb %d",
3707 vec
= SWITCH_LABELS (stmt
);
3708 n
= TREE_VEC_LENGTH (vec
);
3710 /* Mark all the destination basic blocks. */
3711 for (i
= 0; i
< n
; ++i
)
3713 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3714 basic_block label_bb
= label_to_block (lab
);
3716 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3717 label_bb
->aux
= (void *)1;
3720 /* Verify that the case labels are sorted. */
3721 prev
= TREE_VEC_ELT (vec
, 0);
3722 for (i
= 1; i
< n
- 1; ++i
)
3724 tree c
= TREE_VEC_ELT (vec
, i
);
3727 error ("found default case not at end of case vector");
3731 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3733 error ("case labels not sorted:");
3734 print_generic_expr (stderr
, prev
, 0);
3735 fprintf (stderr
," is greater than ");
3736 print_generic_expr (stderr
, c
, 0);
3737 fprintf (stderr
," but comes before it.\n");
3742 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3744 error ("no default case found at end of case vector");
3748 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3752 error ("extra outgoing edge %d->%d",
3753 bb
->index
, e
->dest
->index
);
3756 e
->dest
->aux
= (void *)2;
3757 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3758 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3760 error ("wrong outgoing edge flags at end of bb %d",
3766 /* Check that we have all of them. */
3767 for (i
= 0; i
< n
; ++i
)
3769 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3770 basic_block label_bb
= label_to_block (lab
);
3772 if (label_bb
->aux
!= (void *)2)
3774 error ("missing edge %i->%i",
3775 bb
->index
, label_bb
->index
);
3780 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3781 e
->dest
->aux
= (void *)0;
3788 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3789 verify_dominators (CDI_DOMINATORS
);
3795 /* Updates phi nodes after creating a forwarder block joined
3796 by edge FALLTHRU. */
3799 tree_make_forwarder_block (edge fallthru
)
3803 basic_block dummy
, bb
;
3804 tree phi
, new_phi
, var
;
3806 dummy
= fallthru
->src
;
3807 bb
= fallthru
->dest
;
3809 if (single_pred_p (bb
))
3812 /* If we redirected a branch we must create new phi nodes at the
3814 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3816 var
= PHI_RESULT (phi
);
3817 new_phi
= create_phi_node (var
, bb
);
3818 SSA_NAME_DEF_STMT (var
) = new_phi
;
3819 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3820 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3823 /* Ensure that the PHI node chain is in the same order. */
3824 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3826 /* Add the arguments we have stored on edges. */
3827 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3832 flush_pending_stmts (e
);
3837 /* Return a non-special label in the head of basic block BLOCK.
3838 Create one if it doesn't exist. */
3841 tree_block_label (basic_block bb
)
3843 block_stmt_iterator i
, s
= bsi_start (bb
);
3847 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
3849 stmt
= bsi_stmt (i
);
3850 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3852 label
= LABEL_EXPR_LABEL (stmt
);
3853 if (!DECL_NONLOCAL (label
))
3856 bsi_move_before (&i
, &s
);
3861 label
= create_artificial_label ();
3862 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
3863 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
3868 /* Attempt to perform edge redirection by replacing a possibly complex
3869 jump instruction by a goto or by removing the jump completely.
3870 This can apply only if all edges now point to the same block. The
3871 parameters and return values are equivalent to
3872 redirect_edge_and_branch. */
3875 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
3877 basic_block src
= e
->src
;
3878 block_stmt_iterator b
;
3881 /* We can replace or remove a complex jump only when we have exactly
3883 if (EDGE_COUNT (src
->succs
) != 2
3884 /* Verify that all targets will be TARGET. Specifically, the
3885 edge that is not E must also go to TARGET. */
3886 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
3892 stmt
= bsi_stmt (b
);
3894 if (TREE_CODE (stmt
) == COND_EXPR
3895 || TREE_CODE (stmt
) == SWITCH_EXPR
)
3898 e
= ssa_redirect_edge (e
, target
);
3899 e
->flags
= EDGE_FALLTHRU
;
3907 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
3908 edge representing the redirected branch. */
3911 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
3913 basic_block bb
= e
->src
;
3914 block_stmt_iterator bsi
;
3918 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
3921 if (e
->src
!= ENTRY_BLOCK_PTR
3922 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
3925 if (e
->dest
== dest
)
3928 label
= tree_block_label (dest
);
3930 bsi
= bsi_last (bb
);
3931 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
3933 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
3936 stmt
= (e
->flags
& EDGE_TRUE_VALUE
3937 ? COND_EXPR_THEN (stmt
)
3938 : COND_EXPR_ELSE (stmt
));
3939 GOTO_DESTINATION (stmt
) = label
;
3943 /* No non-abnormal edges should lead from a non-simple goto, and
3944 simple ones should be represented implicitly. */
3949 tree cases
= get_cases_for_edge (e
, stmt
);
3951 /* If we have a list of cases associated with E, then use it
3952 as it's a lot faster than walking the entire case vector. */
3955 edge e2
= find_edge (e
->src
, dest
);
3962 CASE_LABEL (cases
) = label
;
3963 cases
= TREE_CHAIN (cases
);
3966 /* If there was already an edge in the CFG, then we need
3967 to move all the cases associated with E to E2. */
3970 tree cases2
= get_cases_for_edge (e2
, stmt
);
3972 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
3973 TREE_CHAIN (cases2
) = first
;
3978 tree vec
= SWITCH_LABELS (stmt
);
3979 size_t i
, n
= TREE_VEC_LENGTH (vec
);
3981 for (i
= 0; i
< n
; i
++)
3983 tree elt
= TREE_VEC_ELT (vec
, i
);
3985 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
3986 CASE_LABEL (elt
) = label
;
3995 e
->flags
|= EDGE_FALLTHRU
;
3999 /* Otherwise it must be a fallthru edge, and we don't need to
4000 do anything besides redirecting it. */
4001 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4005 /* Update/insert PHI nodes as necessary. */
4007 /* Now update the edges in the CFG. */
4008 e
= ssa_redirect_edge (e
, dest
);
4014 /* Simple wrapper, as we can always redirect fallthru edges. */
4017 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4019 e
= tree_redirect_edge_and_branch (e
, dest
);
4026 /* Splits basic block BB after statement STMT (but at least after the
4027 labels). If STMT is NULL, BB is split just after the labels. */
4030 tree_split_block (basic_block bb
, void *stmt
)
4032 block_stmt_iterator bsi
, bsi_tgt
;
4038 new_bb
= create_empty_bb (bb
);
4040 /* Redirect the outgoing edges. */
4041 new_bb
->succs
= bb
->succs
;
4043 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4046 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4049 /* Move everything from BSI to the new basic block. */
4050 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4052 act
= bsi_stmt (bsi
);
4053 if (TREE_CODE (act
) == LABEL_EXPR
)
4066 bsi_tgt
= bsi_start (new_bb
);
4067 while (!bsi_end_p (bsi
))
4069 act
= bsi_stmt (bsi
);
4071 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4078 /* Moves basic block BB after block AFTER. */
4081 tree_move_block_after (basic_block bb
, basic_block after
)
4083 if (bb
->prev_bb
== after
)
4087 link_block (bb
, after
);
4093 /* Return true if basic_block can be duplicated. */
4096 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4102 /* Create a duplicate of the basic block BB. NOTE: This does not
4103 preserve SSA form. */
4106 tree_duplicate_bb (basic_block bb
)
4109 block_stmt_iterator bsi
, bsi_tgt
;
4112 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4114 /* Copy the PHI nodes. We ignore PHI node arguments here because
4115 the incoming edges have not been setup yet. */
4116 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4118 tree copy
= create_phi_node (PHI_RESULT (phi
), new_bb
);
4119 create_new_def_for (PHI_RESULT (copy
), copy
, PHI_RESULT_PTR (copy
));
4122 /* Keep the chain of PHI nodes in the same order so that they can be
4123 updated by ssa_redirect_edge. */
4124 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4126 bsi_tgt
= bsi_start (new_bb
);
4127 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4129 def_operand_p def_p
;
4130 ssa_op_iter op_iter
;
4134 stmt
= bsi_stmt (bsi
);
4135 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4138 /* Create a new copy of STMT and duplicate STMT's virtual
4140 copy
= unshare_expr (stmt
);
4141 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4142 copy_virtual_operands (copy
, stmt
);
4143 region
= lookup_stmt_eh_region (stmt
);
4145 add_stmt_to_eh_region (copy
, region
);
4147 /* Create new names for all the definitions created by COPY and
4148 add replacement mappings for each new name. */
4149 FOR_EACH_SSA_DEF_OPERAND (def_p
, copy
, op_iter
, SSA_OP_ALL_DEFS
)
4150 create_new_def_for (DEF_FROM_PTR (def_p
), copy
, def_p
);
4157 /* Basic block BB_COPY was created by code duplication. Add phi node
4158 arguments for edges going out of BB_COPY. The blocks that were
4159 duplicated have BB_DUPLICATED set. */
4162 add_phi_args_after_copy_bb (basic_block bb_copy
)
4164 basic_block bb
, dest
;
4167 tree phi
, phi_copy
, phi_next
, def
;
4169 bb
= get_bb_original (bb_copy
);
4171 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4173 if (!phi_nodes (e_copy
->dest
))
4176 if (e_copy
->dest
->flags
& BB_DUPLICATED
)
4177 dest
= get_bb_original (e_copy
->dest
);
4179 dest
= e_copy
->dest
;
4181 e
= find_edge (bb
, dest
);
4184 /* During loop unrolling the target of the latch edge is copied.
4185 In this case we are not looking for edge to dest, but to
4186 duplicated block whose original was dest. */
4187 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4188 if ((e
->dest
->flags
& BB_DUPLICATED
)
4189 && get_bb_original (e
->dest
) == dest
)
4192 gcc_assert (e
!= NULL
);
4195 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4197 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4199 phi_next
= PHI_CHAIN (phi
);
4200 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4201 add_phi_arg (phi_copy
, def
, e_copy
);
4206 /* Blocks in REGION_COPY array of length N_REGION were created by
4207 duplication of basic blocks. Add phi node arguments for edges
4208 going from these blocks. */
4211 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4215 for (i
= 0; i
< n_region
; i
++)
4216 region_copy
[i
]->flags
|= BB_DUPLICATED
;
4218 for (i
= 0; i
< n_region
; i
++)
4219 add_phi_args_after_copy_bb (region_copy
[i
]);
4221 for (i
= 0; i
< n_region
; i
++)
4222 region_copy
[i
]->flags
&= ~BB_DUPLICATED
;
4225 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4226 important exit edge EXIT. By important we mean that no SSA name defined
4227 inside region is live over the other exit edges of the region. All entry
4228 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4229 to the duplicate of the region. SSA form, dominance and loop information
4230 is updated. The new basic blocks are stored to REGION_COPY in the same
4231 order as they had in REGION, provided that REGION_COPY is not NULL.
4232 The function returns false if it is unable to copy the region,
4236 tree_duplicate_sese_region (edge entry
, edge exit
,
4237 basic_block
*region
, unsigned n_region
,
4238 basic_block
*region_copy
)
4241 bool free_region_copy
= false, copying_header
= false;
4242 struct loop
*loop
= entry
->dest
->loop_father
;
4246 int total_freq
, entry_freq
;
4248 if (!can_copy_bbs_p (region
, n_region
))
4251 /* Some sanity checking. Note that we do not check for all possible
4252 missuses of the functions. I.e. if you ask to copy something weird,
4253 it will work, but the state of structures probably will not be
4255 for (i
= 0; i
< n_region
; i
++)
4257 /* We do not handle subloops, i.e. all the blocks must belong to the
4259 if (region
[i
]->loop_father
!= loop
)
4262 if (region
[i
] != entry
->dest
4263 && region
[i
] == loop
->header
)
4269 /* In case the function is used for loop header copying (which is the primary
4270 use), ensure that EXIT and its copy will be new latch and entry edges. */
4271 if (loop
->header
== entry
->dest
)
4273 copying_header
= true;
4274 loop
->copy
= loop
->outer
;
4276 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4279 for (i
= 0; i
< n_region
; i
++)
4280 if (region
[i
] != exit
->src
4281 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4287 region_copy
= xmalloc (sizeof (basic_block
) * n_region
);
4288 free_region_copy
= true;
4291 gcc_assert (!need_ssa_update_p ());
4293 /* Record blocks outside the region that are dominated by something
4295 doms
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4296 initialize_original_copy_tables ();
4298 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
4300 total_freq
= entry
->dest
->frequency
;
4301 entry_freq
= EDGE_FREQUENCY (entry
);
4302 /* Fix up corner cases, to avoid division by zero or creation of negative
4304 if (total_freq
== 0)
4306 else if (entry_freq
> total_freq
)
4307 entry_freq
= total_freq
;
4309 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
);
4310 scale_bbs_frequencies_int (region
, n_region
, total_freq
- entry_freq
,
4312 scale_bbs_frequencies_int (region_copy
, n_region
, entry_freq
, total_freq
);
4316 loop
->header
= exit
->dest
;
4317 loop
->latch
= exit
->src
;
4320 /* Redirect the entry and add the phi node arguments. */
4321 redirected
= redirect_edge_and_branch (entry
, get_bb_copy (entry
->dest
));
4322 gcc_assert (redirected
!= NULL
);
4323 flush_pending_stmts (entry
);
4325 /* Concerning updating of dominators: We must recount dominators
4326 for entry block and its copy. Anything that is outside of the
4327 region, but was dominated by something inside needs recounting as
4329 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
4330 doms
[n_doms
++] = get_bb_original (entry
->dest
);
4331 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
4334 /* Add the other PHI node arguments. */
4335 add_phi_args_after_copy (region_copy
, n_region
);
4337 /* Update the SSA web. */
4338 update_ssa (TODO_update_ssa
);
4340 if (free_region_copy
)
4343 free_original_copy_tables ();
4348 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
4351 dump_function_to_file (tree fn
, FILE *file
, int flags
)
4353 tree arg
, vars
, var
;
4354 bool ignore_topmost_bind
= false, any_var
= false;
4358 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
4360 arg
= DECL_ARGUMENTS (fn
);
4363 print_generic_expr (file
, arg
, dump_flags
);
4364 if (TREE_CHAIN (arg
))
4365 fprintf (file
, ", ");
4366 arg
= TREE_CHAIN (arg
);
4368 fprintf (file
, ")\n");
4370 if (flags
& TDF_DETAILS
)
4371 dump_eh_tree (file
, DECL_STRUCT_FUNCTION (fn
));
4372 if (flags
& TDF_RAW
)
4374 dump_node (fn
, TDF_SLIM
| flags
, file
);
4378 /* When GIMPLE is lowered, the variables are no longer available in
4379 BIND_EXPRs, so display them separately. */
4380 if (cfun
&& cfun
->decl
== fn
&& cfun
->unexpanded_var_list
)
4382 ignore_topmost_bind
= true;
4384 fprintf (file
, "{\n");
4385 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
4387 var
= TREE_VALUE (vars
);
4389 print_generic_decl (file
, var
, flags
);
4390 fprintf (file
, "\n");
4396 if (cfun
&& cfun
->decl
== fn
&& cfun
->cfg
&& basic_block_info
)
4398 /* Make a CFG based dump. */
4399 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
4400 if (!ignore_topmost_bind
)
4401 fprintf (file
, "{\n");
4403 if (any_var
&& n_basic_blocks
)
4404 fprintf (file
, "\n");
4407 dump_generic_bb (file
, bb
, 2, flags
);
4409 fprintf (file
, "}\n");
4410 check_bb_profile (EXIT_BLOCK_PTR
, file
);
4416 /* Make a tree based dump. */
4417 chain
= DECL_SAVED_TREE (fn
);
4419 if (TREE_CODE (chain
) == BIND_EXPR
)
4421 if (ignore_topmost_bind
)
4423 chain
= BIND_EXPR_BODY (chain
);
4431 if (!ignore_topmost_bind
)
4432 fprintf (file
, "{\n");
4437 fprintf (file
, "\n");
4439 print_generic_stmt_indented (file
, chain
, flags
, indent
);
4440 if (ignore_topmost_bind
)
4441 fprintf (file
, "}\n");
4444 fprintf (file
, "\n\n");
4448 /* Pretty print of the loops intermediate representation. */
4449 static void print_loop (FILE *, struct loop
*, int);
4450 static void print_pred_bbs (FILE *, basic_block bb
);
4451 static void print_succ_bbs (FILE *, basic_block bb
);
4454 /* Print the predecessors indexes of edge E on FILE. */
4457 print_pred_bbs (FILE *file
, basic_block bb
)
4462 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4463 fprintf (file
, "bb_%d", e
->src
->index
);
4467 /* Print the successors indexes of edge E on FILE. */
4470 print_succ_bbs (FILE *file
, basic_block bb
)
4475 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4476 fprintf (file
, "bb_%d", e
->src
->index
);
4480 /* Pretty print LOOP on FILE, indented INDENT spaces. */
4483 print_loop (FILE *file
, struct loop
*loop
, int indent
)
4491 s_indent
= (char *) alloca ((size_t) indent
+ 1);
4492 memset ((void *) s_indent
, ' ', (size_t) indent
);
4493 s_indent
[indent
] = '\0';
4495 /* Print the loop's header. */
4496 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
4498 /* Print the loop's body. */
4499 fprintf (file
, "%s{\n", s_indent
);
4501 if (bb
->loop_father
== loop
)
4503 /* Print the basic_block's header. */
4504 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
4505 print_pred_bbs (file
, bb
);
4506 fprintf (file
, "}, succs = {");
4507 print_succ_bbs (file
, bb
);
4508 fprintf (file
, "})\n");
4510 /* Print the basic_block's body. */
4511 fprintf (file
, "%s {\n", s_indent
);
4512 tree_dump_bb (bb
, file
, indent
+ 4);
4513 fprintf (file
, "%s }\n", s_indent
);
4516 print_loop (file
, loop
->inner
, indent
+ 2);
4517 fprintf (file
, "%s}\n", s_indent
);
4518 print_loop (file
, loop
->next
, indent
);
4522 /* Follow a CFG edge from the entry point of the program, and on entry
4523 of a loop, pretty print the loop structure on FILE. */
4526 print_loop_ir (FILE *file
)
4530 bb
= BASIC_BLOCK (0);
4531 if (bb
&& bb
->loop_father
)
4532 print_loop (file
, bb
->loop_father
, 0);
4536 /* Debugging loops structure at tree level. */
4539 debug_loop_ir (void)
4541 print_loop_ir (stderr
);
4545 /* Return true if BB ends with a call, possibly followed by some
4546 instructions that must stay with the call. Return false,
4550 tree_block_ends_with_call_p (basic_block bb
)
4552 block_stmt_iterator bsi
= bsi_last (bb
);
4553 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
4557 /* Return true if BB ends with a conditional branch. Return false,
4561 tree_block_ends_with_condjump_p (basic_block bb
)
4563 tree stmt
= last_stmt (bb
);
4564 return (stmt
&& TREE_CODE (stmt
) == COND_EXPR
);
4568 /* Return true if we need to add fake edge to exit at statement T.
4569 Helper function for tree_flow_call_edges_add. */
4572 need_fake_edge_p (tree t
)
4576 /* NORETURN and LONGJMP calls already have an edge to exit.
4577 CONST and PURE calls do not need one.
4578 We don't currently check for CONST and PURE here, although
4579 it would be a good idea, because those attributes are
4580 figured out from the RTL in mark_constant_function, and
4581 the counter incrementation code from -fprofile-arcs
4582 leads to different results from -fbranch-probabilities. */
4583 call
= get_call_expr_in (t
);
4585 && !(call_expr_flags (call
) & ECF_NORETURN
))
4588 if (TREE_CODE (t
) == ASM_EXPR
4589 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
4596 /* Add fake edges to the function exit for any non constant and non
4597 noreturn calls, volatile inline assembly in the bitmap of blocks
4598 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
4599 the number of blocks that were split.
4601 The goal is to expose cases in which entering a basic block does
4602 not imply that all subsequent instructions must be executed. */
4605 tree_flow_call_edges_add (sbitmap blocks
)
4608 int blocks_split
= 0;
4609 int last_bb
= last_basic_block
;
4610 bool check_last_block
= false;
4612 if (n_basic_blocks
== 0)
4616 check_last_block
= true;
4618 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
4620 /* In the last basic block, before epilogue generation, there will be
4621 a fallthru edge to EXIT. Special care is required if the last insn
4622 of the last basic block is a call because make_edge folds duplicate
4623 edges, which would result in the fallthru edge also being marked
4624 fake, which would result in the fallthru edge being removed by
4625 remove_fake_edges, which would result in an invalid CFG.
4627 Moreover, we can't elide the outgoing fake edge, since the block
4628 profiler needs to take this into account in order to solve the minimal
4629 spanning tree in the case that the call doesn't return.
4631 Handle this by adding a dummy instruction in a new last basic block. */
4632 if (check_last_block
)
4634 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
4635 block_stmt_iterator bsi
= bsi_last (bb
);
4637 if (!bsi_end_p (bsi
))
4640 if (need_fake_edge_p (t
))
4644 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4647 bsi_insert_on_edge (e
, build_empty_stmt ());
4648 bsi_commit_edge_inserts ();
4653 /* Now add fake edges to the function exit for any non constant
4654 calls since there is no way that we can determine if they will
4656 for (i
= 0; i
< last_bb
; i
++)
4658 basic_block bb
= BASIC_BLOCK (i
);
4659 block_stmt_iterator bsi
;
4660 tree stmt
, last_stmt
;
4665 if (blocks
&& !TEST_BIT (blocks
, i
))
4668 bsi
= bsi_last (bb
);
4669 if (!bsi_end_p (bsi
))
4671 last_stmt
= bsi_stmt (bsi
);
4674 stmt
= bsi_stmt (bsi
);
4675 if (need_fake_edge_p (stmt
))
4678 /* The handling above of the final block before the
4679 epilogue should be enough to verify that there is
4680 no edge to the exit block in CFG already.
4681 Calling make_edge in such case would cause us to
4682 mark that edge as fake and remove it later. */
4683 #ifdef ENABLE_CHECKING
4684 if (stmt
== last_stmt
)
4686 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
4687 gcc_assert (e
== NULL
);
4691 /* Note that the following may create a new basic block
4692 and renumber the existing basic blocks. */
4693 if (stmt
!= last_stmt
)
4695 e
= split_block (bb
, stmt
);
4699 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
4703 while (!bsi_end_p (bsi
));
4708 verify_flow_info ();
4710 return blocks_split
;
4714 tree_purge_dead_eh_edges (basic_block bb
)
4716 bool changed
= false;
4719 tree stmt
= last_stmt (bb
);
4721 if (stmt
&& tree_can_throw_internal (stmt
))
4724 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
4726 if (e
->flags
& EDGE_EH
)
4735 /* Removal of dead EH edges might change dominators of not
4736 just immediate successors. E.g. when bb1 is changed so that
4737 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
4738 eh edges purged by this function in:
4750 idom(bb5) must be recomputed. For now just free the dominance
4753 free_dominance_info (CDI_DOMINATORS
);
4759 tree_purge_all_dead_eh_edges (bitmap blocks
)
4761 bool changed
= false;
4765 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
4767 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
4773 /* This function is called whenever a new edge is created or
4777 tree_execute_on_growing_pred (edge e
)
4779 basic_block bb
= e
->dest
;
4782 reserve_phi_args_for_new_edge (bb
);
4785 /* This function is called immediately before edge E is removed from
4786 the edge vector E->dest->preds. */
4789 tree_execute_on_shrinking_pred (edge e
)
4791 if (phi_nodes (e
->dest
))
4792 remove_phi_args (e
);
4795 /*---------------------------------------------------------------------------
4796 Helper functions for Loop versioning
4797 ---------------------------------------------------------------------------*/
4799 /* Adjust phi nodes for 'first' basic block. 'second' basic block is a copy
4800 of 'first'. Both of them are dominated by 'new_head' basic block. When
4801 'new_head' was created by 'second's incoming edge it received phi arguments
4802 on the edge by split_edge(). Later, additional edge 'e' was created to
4803 connect 'new_head' and 'first'. Now this routine adds phi args on this
4804 additional edge 'e' that new_head to second edge received as part of edge
4809 tree_lv_adjust_loop_header_phi (basic_block first
, basic_block second
,
4810 basic_block new_head
, edge e
)
4813 edge e2
= find_edge (new_head
, second
);
4815 /* Because NEW_HEAD has been created by splitting SECOND's incoming
4816 edge, we should always have an edge from NEW_HEAD to SECOND. */
4817 gcc_assert (e2
!= NULL
);
4819 /* Browse all 'second' basic block phi nodes and add phi args to
4820 edge 'e' for 'first' head. PHI args are always in correct order. */
4822 for (phi2
= phi_nodes (second
), phi1
= phi_nodes (first
);
4824 phi2
= PHI_CHAIN (phi2
), phi1
= PHI_CHAIN (phi1
))
4826 tree def
= PHI_ARG_DEF (phi2
, e2
->dest_idx
);
4827 add_phi_arg (phi1
, def
, e
);
4831 /* Adds a if else statement to COND_BB with condition COND_EXPR.
4832 SECOND_HEAD is the destination of the THEN and FIRST_HEAD is
4833 the destination of the ELSE part. */
4835 tree_lv_add_condition_to_bb (basic_block first_head
, basic_block second_head
,
4836 basic_block cond_bb
, void *cond_e
)
4838 block_stmt_iterator bsi
;
4839 tree goto1
= NULL_TREE
;
4840 tree goto2
= NULL_TREE
;
4841 tree new_cond_expr
= NULL_TREE
;
4842 tree cond_expr
= (tree
) cond_e
;
4845 /* Build new conditional expr */
4846 goto1
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (first_head
));
4847 goto2
= build1 (GOTO_EXPR
, void_type_node
, tree_block_label (second_head
));
4848 new_cond_expr
= build3 (COND_EXPR
, void_type_node
, cond_expr
, goto1
, goto2
);
4850 /* Add new cond in cond_bb. */
4851 bsi
= bsi_start (cond_bb
);
4852 bsi_insert_after (&bsi
, new_cond_expr
, BSI_NEW_STMT
);
4853 /* Adjust edges appropriately to connect new head with first head
4854 as well as second head. */
4855 e0
= single_succ_edge (cond_bb
);
4856 e0
->flags
&= ~EDGE_FALLTHRU
;
4857 e0
->flags
|= EDGE_FALSE_VALUE
;
4860 struct cfg_hooks tree_cfg_hooks
= {
4862 tree_verify_flow_info
,
4863 tree_dump_bb
, /* dump_bb */
4864 create_bb
, /* create_basic_block */
4865 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
4866 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
4867 remove_bb
, /* delete_basic_block */
4868 tree_split_block
, /* split_block */
4869 tree_move_block_after
, /* move_block_after */
4870 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
4871 tree_merge_blocks
, /* merge_blocks */
4872 tree_predict_edge
, /* predict_edge */
4873 tree_predicted_by_p
, /* predicted_by_p */
4874 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
4875 tree_duplicate_bb
, /* duplicate_block */
4876 tree_split_edge
, /* split_edge */
4877 tree_make_forwarder_block
, /* make_forward_block */
4878 NULL
, /* tidy_fallthru_edge */
4879 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
4880 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
4881 tree_flow_call_edges_add
, /* flow_call_edges_add */
4882 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
4883 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
4884 tree_duplicate_loop_to_header_edge
, /* duplicate loop for trees */
4885 tree_lv_add_condition_to_bb
, /* lv_add_condition_to_bb */
4886 tree_lv_adjust_loop_header_phi
, /* lv_adjust_loop_header_phi*/
4887 extract_true_false_edges_from_block
, /* extract_cond_bb_edges */
4888 flush_pending_stmts
/* flush_pending_stmts */
4892 /* Split all critical edges. */
4895 split_critical_edges (void)
4901 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
4902 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
4903 mappings around the calls to split_edge. */
4904 start_recording_case_labels ();
4907 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4908 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
4913 end_recording_case_labels ();
4916 struct tree_opt_pass pass_split_crit_edges
=
4918 "crited", /* name */
4920 split_critical_edges
, /* execute */
4923 0, /* static_pass_number */
4924 TV_TREE_SPLIT_EDGES
, /* tv_id */
4925 PROP_cfg
, /* properties required */
4926 PROP_no_crit_edges
, /* properties_provided */
4927 0, /* properties_destroyed */
4928 0, /* todo_flags_start */
4929 TODO_dump_func
, /* todo_flags_finish */
4934 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
4935 a temporary, make sure and register it to be renamed if necessary,
4936 and finally return the temporary. Put the statements to compute
4937 EXP before the current statement in BSI. */
4940 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
4942 tree t
, new_stmt
, orig_stmt
;
4944 if (is_gimple_val (exp
))
4947 t
= make_rename_temp (type
, NULL
);
4948 new_stmt
= build (MODIFY_EXPR
, type
, t
, exp
);
4950 orig_stmt
= bsi_stmt (*bsi
);
4951 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
4952 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
4954 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
4959 /* Build a ternary operation and gimplify it. Emit code before BSI.
4960 Return the gimple_val holding the result. */
4963 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
4964 tree type
, tree a
, tree b
, tree c
)
4968 ret
= fold_build3 (code
, type
, a
, b
, c
);
4971 return gimplify_val (bsi
, type
, ret
);
4974 /* Build a binary operation and gimplify it. Emit code before BSI.
4975 Return the gimple_val holding the result. */
4978 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
4979 tree type
, tree a
, tree b
)
4983 ret
= fold_build2 (code
, type
, a
, b
);
4986 return gimplify_val (bsi
, type
, ret
);
4989 /* Build a unary operation and gimplify it. Emit code before BSI.
4990 Return the gimple_val holding the result. */
4993 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
4998 ret
= fold_build1 (code
, type
, a
);
5001 return gimplify_val (bsi
, type
, ret
);
5006 /* Emit return warnings. */
5009 execute_warn_function_return (void)
5011 #ifdef USE_MAPPED_LOCATION
5012 source_location location
;
5020 /* If we have a path to EXIT, then we do return. */
5021 if (TREE_THIS_VOLATILE (cfun
->decl
)
5022 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5024 #ifdef USE_MAPPED_LOCATION
5025 location
= UNKNOWN_LOCATION
;
5029 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5031 last
= last_stmt (e
->src
);
5032 if (TREE_CODE (last
) == RETURN_EXPR
5033 #ifdef USE_MAPPED_LOCATION
5034 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5036 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5040 #ifdef USE_MAPPED_LOCATION
5041 if (location
== UNKNOWN_LOCATION
)
5042 location
= cfun
->function_end_locus
;
5043 warning (0, "%H%<noreturn%> function does return", &location
);
5046 locus
= &cfun
->function_end_locus
;
5047 warning (0, "%H%<noreturn%> function does return", locus
);
5051 /* If we see "return;" in some basic block, then we do reach the end
5052 without returning a value. */
5053 else if (warn_return_type
5054 && !TREE_NO_WARNING (cfun
->decl
)
5055 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5056 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5058 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5060 tree last
= last_stmt (e
->src
);
5061 if (TREE_CODE (last
) == RETURN_EXPR
5062 && TREE_OPERAND (last
, 0) == NULL
)
5064 #ifdef USE_MAPPED_LOCATION
5065 location
= EXPR_LOCATION (last
);
5066 if (location
== UNKNOWN_LOCATION
)
5067 location
= cfun
->function_end_locus
;
5068 warning (0, "%Hcontrol reaches end of non-void function", &location
);
5070 locus
= EXPR_LOCUS (last
);
5072 locus
= &cfun
->function_end_locus
;
5073 warning (0, "%Hcontrol reaches end of non-void function", locus
);
5075 TREE_NO_WARNING (cfun
->decl
) = 1;
5083 /* Given a basic block B which ends with a conditional and has
5084 precisely two successors, determine which of the edges is taken if
5085 the conditional is true and which is taken if the conditional is
5086 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5089 extract_true_false_edges_from_block (basic_block b
,
5093 edge e
= EDGE_SUCC (b
, 0);
5095 if (e
->flags
& EDGE_TRUE_VALUE
)
5098 *false_edge
= EDGE_SUCC (b
, 1);
5103 *true_edge
= EDGE_SUCC (b
, 1);
5107 struct tree_opt_pass pass_warn_function_return
=
5111 execute_warn_function_return
, /* execute */
5114 0, /* static_pass_number */
5116 PROP_cfg
, /* properties_required */
5117 0, /* properties_provided */
5118 0, /* properties_destroyed */
5119 0, /* todo_flags_start */
5120 0, /* todo_flags_finish */
5124 /* Emit noreturn warnings. */
5127 execute_warn_function_noreturn (void)
5129 if (warn_missing_noreturn
5130 && !TREE_THIS_VOLATILE (cfun
->decl
)
5131 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5132 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5133 warning (OPT_Wmissing_noreturn
, "%Jfunction might be possible candidate "
5134 "for attribute %<noreturn%>",
5138 struct tree_opt_pass pass_warn_function_noreturn
=
5142 execute_warn_function_noreturn
, /* execute */
5145 0, /* static_pass_number */
5147 PROP_cfg
, /* properties_required */
5148 0, /* properties_provided */
5149 0, /* properties_destroyed */
5150 0, /* todo_flags_start */
5151 0, /* todo_flags_finish */