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, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
29 #include "hard-reg-set.h"
30 #include "basic-block.h"
37 #include "langhooks.h"
38 #include "diagnostic.h"
39 #include "tree-flow.h"
41 #include "tree-dump.h"
42 #include "tree-pass.h"
46 #include "cfglayout.h"
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 /* Mapping of labels to their associated blocks. This can greatly speed up
58 building of the CFG in code with lots of gotos. */
59 static GTY(()) varray_type label_to_block_map
;
61 /* This hash table allows us to efficiently lookup all CASE_LABEL_EXPRs
62 which use a particular edge. The CASE_LABEL_EXPRs are chained together
63 via their TREE_CHAIN field, which we clear after we're done with the
64 hash table to prevent problems with duplication of SWITCH_EXPRs.
66 Access to this list of CASE_LABEL_EXPRs allows us to efficiently
67 update the case vector in response to edge redirections.
69 Right now this table is set up and torn down at key points in the
70 compilation process. It would be nice if we could make the table
71 more persistent. The key is getting notification of changes to
72 the CFG (particularly edge removal, creation and redirection). */
74 struct edge_to_cases_elt
76 /* The edge itself. Necessary for hashing and equality tests. */
79 /* The case labels associated with this edge. We link these up via
80 their TREE_CHAIN field, then we wipe out the TREE_CHAIN fields
81 when we destroy the hash table. This prevents problems when copying
86 static htab_t edge_to_cases
;
91 long num_merged_labels
;
94 static struct cfg_stats_d cfg_stats
;
96 /* Nonzero if we found a computed goto while building basic blocks. */
97 static bool found_computed_goto
;
99 /* Basic blocks and flowgraphs. */
100 static basic_block
create_bb (void *, void *, basic_block
);
101 static void create_block_annotation (basic_block
);
102 static void free_blocks_annotations (void);
103 static void clear_blocks_annotations (void);
104 static void make_blocks (tree
);
105 static void factor_computed_gotos (void);
108 static void make_edges (void);
109 static void make_ctrl_stmt_edges (basic_block
);
110 static void make_exit_edges (basic_block
);
111 static void make_cond_expr_edges (basic_block
);
112 static void make_switch_expr_edges (basic_block
);
113 static void make_goto_expr_edges (basic_block
);
114 static edge
tree_redirect_edge_and_branch (edge
, basic_block
);
115 static edge
tree_try_redirect_by_replacing_jump (edge
, basic_block
);
116 static void split_critical_edges (void);
117 static bool remove_fallthru_edge (VEC(edge
) *);
119 /* Various helpers. */
120 static inline bool stmt_starts_bb_p (tree
, tree
);
121 static int tree_verify_flow_info (void);
122 static void tree_make_forwarder_block (edge
);
123 static bool tree_forwarder_block_p (basic_block
, bool);
124 static void tree_cfg2vcg (FILE *);
126 /* Flowgraph optimization and cleanup. */
127 static void tree_merge_blocks (basic_block
, basic_block
);
128 static bool tree_can_merge_blocks_p (basic_block
, basic_block
);
129 static void remove_bb (basic_block
);
130 static bool cleanup_control_flow (void);
131 static bool cleanup_control_expr_graph (basic_block
, block_stmt_iterator
);
132 static edge
find_taken_edge_cond_expr (basic_block
, tree
);
133 static edge
find_taken_edge_switch_expr (basic_block
, tree
);
134 static tree
find_case_label_for_value (tree
, tree
);
135 static bool phi_alternatives_equal (basic_block
, edge
, edge
);
136 static bool cleanup_forwarder_blocks (void);
139 /*---------------------------------------------------------------------------
141 ---------------------------------------------------------------------------*/
143 /* Entry point to the CFG builder for trees. TP points to the list of
144 statements to be added to the flowgraph. */
147 build_tree_cfg (tree
*tp
)
149 /* Register specific tree functions. */
150 tree_register_cfg_hooks ();
152 /* Initialize rbi_pool. */
155 /* Initialize the basic block array. */
157 profile_status
= PROFILE_ABSENT
;
159 last_basic_block
= 0;
160 VARRAY_BB_INIT (basic_block_info
, initial_cfg_capacity
, "basic_block_info");
161 memset ((void *) &cfg_stats
, 0, sizeof (cfg_stats
));
163 /* Build a mapping of labels to their associated blocks. */
164 VARRAY_BB_INIT (label_to_block_map
, initial_cfg_capacity
,
165 "label to block map");
167 ENTRY_BLOCK_PTR
->next_bb
= EXIT_BLOCK_PTR
;
168 EXIT_BLOCK_PTR
->prev_bb
= ENTRY_BLOCK_PTR
;
170 found_computed_goto
= 0;
173 /* Computed gotos are hell to deal with, especially if there are
174 lots of them with a large number of destinations. So we factor
175 them to a common computed goto location before we build the
176 edge list. After we convert back to normal form, we will un-factor
177 the computed gotos since factoring introduces an unwanted jump. */
178 if (found_computed_goto
)
179 factor_computed_gotos ();
181 /* Make sure there is always at least one block, even if it's empty. */
182 if (n_basic_blocks
== 0)
183 create_empty_bb (ENTRY_BLOCK_PTR
);
185 create_block_annotation (ENTRY_BLOCK_PTR
);
186 create_block_annotation (EXIT_BLOCK_PTR
);
188 /* Adjust the size of the array. */
189 VARRAY_GROW (basic_block_info
, n_basic_blocks
);
191 /* To speed up statement iterator walks, we first purge dead labels. */
192 cleanup_dead_labels ();
194 /* Group case nodes to reduce the number of edges.
195 We do this after cleaning up dead labels because otherwise we miss
196 a lot of obvious case merging opportunities. */
197 group_case_labels ();
199 /* Create the edges of the flowgraph. */
202 /* Debugging dumps. */
204 /* Write the flowgraph to a VCG file. */
206 int local_dump_flags
;
207 FILE *dump_file
= dump_begin (TDI_vcg
, &local_dump_flags
);
210 tree_cfg2vcg (dump_file
);
211 dump_end (TDI_vcg
, dump_file
);
215 /* Dump a textual representation of the flowgraph. */
217 dump_tree_cfg (dump_file
, dump_flags
);
221 execute_build_cfg (void)
223 build_tree_cfg (&DECL_SAVED_TREE (current_function_decl
));
226 struct tree_opt_pass pass_build_cfg
=
230 execute_build_cfg
, /* execute */
233 0, /* static_pass_number */
234 TV_TREE_CFG
, /* tv_id */
235 PROP_gimple_leh
, /* properties_required */
236 PROP_cfg
, /* properties_provided */
237 0, /* properties_destroyed */
238 0, /* todo_flags_start */
239 TODO_verify_stmts
, /* todo_flags_finish */
243 /* Search the CFG for any computed gotos. If found, factor them to a
244 common computed goto site. Also record the location of that site so
245 that we can un-factor the gotos after we have converted back to
249 factor_computed_gotos (void)
252 tree factored_label_decl
= NULL
;
254 tree factored_computed_goto_label
= NULL
;
255 tree factored_computed_goto
= NULL
;
257 /* We know there are one or more computed gotos in this function.
258 Examine the last statement in each basic block to see if the block
259 ends with a computed goto. */
263 block_stmt_iterator bsi
= bsi_last (bb
);
268 last
= bsi_stmt (bsi
);
270 /* Ignore the computed goto we create when we factor the original
272 if (last
== factored_computed_goto
)
275 /* If the last statement is a computed goto, factor it. */
276 if (computed_goto_p (last
))
280 /* The first time we find a computed goto we need to create
281 the factored goto block and the variable each original
282 computed goto will use for their goto destination. */
283 if (! factored_computed_goto
)
285 basic_block new_bb
= create_empty_bb (bb
);
286 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
288 /* Create the destination of the factored goto. Each original
289 computed goto will put its desired destination into this
290 variable and jump to the label we create immediately
292 var
= create_tmp_var (ptr_type_node
, "gotovar");
294 /* Build a label for the new block which will contain the
295 factored computed goto. */
296 factored_label_decl
= create_artificial_label ();
297 factored_computed_goto_label
298 = build1 (LABEL_EXPR
, void_type_node
, factored_label_decl
);
299 bsi_insert_after (&new_bsi
, factored_computed_goto_label
,
302 /* Build our new computed goto. */
303 factored_computed_goto
= build1 (GOTO_EXPR
, void_type_node
, var
);
304 bsi_insert_after (&new_bsi
, factored_computed_goto
,
308 /* Copy the original computed goto's destination into VAR. */
309 assignment
= build (MODIFY_EXPR
, ptr_type_node
,
310 var
, GOTO_DESTINATION (last
));
311 bsi_insert_before (&bsi
, assignment
, BSI_SAME_STMT
);
313 /* And re-vector the computed goto to the new destination. */
314 GOTO_DESTINATION (last
) = factored_label_decl
;
320 /* Create annotations for a single basic block. */
323 create_block_annotation (basic_block bb
)
325 /* Verify that the tree_annotations field is clear. */
326 gcc_assert (!bb
->tree_annotations
);
327 bb
->tree_annotations
= ggc_alloc_cleared (sizeof (struct bb_ann_d
));
331 /* Free the annotations for all the basic blocks. */
333 static void free_blocks_annotations (void)
335 clear_blocks_annotations ();
339 /* Clear the annotations for all the basic blocks. */
342 clear_blocks_annotations (void)
346 FOR_BB_BETWEEN (bb
, ENTRY_BLOCK_PTR
, NULL
, next_bb
)
347 bb
->tree_annotations
= NULL
;
351 /* Build a flowgraph for the statement_list STMT_LIST. */
354 make_blocks (tree stmt_list
)
356 tree_stmt_iterator i
= tsi_start (stmt_list
);
358 bool start_new_block
= true;
359 bool first_stmt_of_list
= true;
360 basic_block bb
= ENTRY_BLOCK_PTR
;
362 while (!tsi_end_p (i
))
369 /* If the statement starts a new basic block or if we have determined
370 in a previous pass that we need to create a new block for STMT, do
372 if (start_new_block
|| stmt_starts_bb_p (stmt
, prev_stmt
))
374 if (!first_stmt_of_list
)
375 stmt_list
= tsi_split_statement_list_before (&i
);
376 bb
= create_basic_block (stmt_list
, NULL
, bb
);
377 start_new_block
= false;
380 /* Now add STMT to BB and create the subgraphs for special statement
382 set_bb_for_stmt (stmt
, bb
);
384 if (computed_goto_p (stmt
))
385 found_computed_goto
= true;
387 /* If STMT is a basic block terminator, set START_NEW_BLOCK for the
389 if (stmt_ends_bb_p (stmt
))
390 start_new_block
= true;
393 first_stmt_of_list
= false;
398 /* Create and return a new empty basic block after bb AFTER. */
401 create_bb (void *h
, void *e
, basic_block after
)
407 /* Create and initialize a new basic block. Since alloc_block uses
408 ggc_alloc_cleared to allocate a basic block, we do not have to
409 clear the newly allocated basic block here. */
412 bb
->index
= last_basic_block
;
414 bb
->stmt_list
= h
? h
: alloc_stmt_list ();
416 /* Add the new block to the linked list of blocks. */
417 link_block (bb
, after
);
419 /* Grow the basic block array if needed. */
420 if ((size_t) last_basic_block
== VARRAY_SIZE (basic_block_info
))
422 size_t new_size
= last_basic_block
+ (last_basic_block
+ 3) / 4;
423 VARRAY_GROW (basic_block_info
, new_size
);
426 /* Add the newly created block to the array. */
427 BASIC_BLOCK (last_basic_block
) = bb
;
429 create_block_annotation (bb
);
434 initialize_bb_rbi (bb
);
439 /*---------------------------------------------------------------------------
441 ---------------------------------------------------------------------------*/
443 /* Join all the blocks in the flowgraph. */
450 /* Create an edge from entry to the first block with executable
452 make_edge (ENTRY_BLOCK_PTR
, BASIC_BLOCK (0), EDGE_FALLTHRU
);
454 /* Traverse the basic block array placing edges. */
457 tree first
= first_stmt (bb
);
458 tree last
= last_stmt (bb
);
462 /* Edges for statements that always alter flow control. */
463 if (is_ctrl_stmt (last
))
464 make_ctrl_stmt_edges (bb
);
466 /* Edges for statements that sometimes alter flow control. */
467 if (is_ctrl_altering_stmt (last
))
468 make_exit_edges (bb
);
471 /* Finally, if no edges were created above, this is a regular
472 basic block that only needs a fallthru edge. */
473 if (EDGE_COUNT (bb
->succs
) == 0)
474 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
477 /* We do not care about fake edges, so remove any that the CFG
478 builder inserted for completeness. */
479 remove_fake_exit_edges ();
481 /* Clean up the graph and warn for unreachable code. */
486 /* Create edges for control statement at basic block BB. */
489 make_ctrl_stmt_edges (basic_block bb
)
491 tree last
= last_stmt (bb
);
494 switch (TREE_CODE (last
))
497 make_goto_expr_edges (bb
);
501 make_edge (bb
, EXIT_BLOCK_PTR
, 0);
505 make_cond_expr_edges (bb
);
509 make_switch_expr_edges (bb
);
513 make_eh_edges (last
);
514 /* Yet another NORETURN hack. */
515 if (EDGE_COUNT (bb
->succs
) == 0)
516 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
525 /* Create exit edges for statements in block BB that alter the flow of
526 control. Statements that alter the control flow are 'goto', 'return'
527 and calls to non-returning functions. */
530 make_exit_edges (basic_block bb
)
532 tree last
= last_stmt (bb
), op
;
535 switch (TREE_CODE (last
))
538 /* If this function receives a nonlocal goto, then we need to
539 make edges from this call site to all the nonlocal goto
541 if (TREE_SIDE_EFFECTS (last
)
542 && current_function_has_nonlocal_label
)
543 make_goto_expr_edges (bb
);
545 /* If this statement has reachable exception handlers, then
546 create abnormal edges to them. */
547 make_eh_edges (last
);
549 /* Some calls are known not to return. For such calls we create
552 We really need to revamp how we build edges so that it's not
553 such a bloody pain to avoid creating edges for this case since
554 all we do is remove these edges when we're done building the
556 if (call_expr_flags (last
) & ECF_NORETURN
)
558 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
562 /* Don't forget the fall-thru edge. */
563 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
567 /* A MODIFY_EXPR may have a CALL_EXPR on its RHS and the CALL_EXPR
568 may have an abnormal edge. Search the RHS for this case and
569 create any required edges. */
570 op
= get_call_expr_in (last
);
571 if (op
&& TREE_SIDE_EFFECTS (op
)
572 && current_function_has_nonlocal_label
)
573 make_goto_expr_edges (bb
);
575 make_eh_edges (last
);
576 make_edge (bb
, bb
->next_bb
, EDGE_FALLTHRU
);
585 /* Create the edges for a COND_EXPR starting at block BB.
586 At this point, both clauses must contain only simple gotos. */
589 make_cond_expr_edges (basic_block bb
)
591 tree entry
= last_stmt (bb
);
592 basic_block then_bb
, else_bb
;
593 tree then_label
, else_label
;
596 gcc_assert (TREE_CODE (entry
) == COND_EXPR
);
598 /* Entry basic blocks for each component. */
599 then_label
= GOTO_DESTINATION (COND_EXPR_THEN (entry
));
600 else_label
= GOTO_DESTINATION (COND_EXPR_ELSE (entry
));
601 then_bb
= label_to_block (then_label
);
602 else_bb
= label_to_block (else_label
);
604 make_edge (bb
, then_bb
, EDGE_TRUE_VALUE
);
605 make_edge (bb
, else_bb
, EDGE_FALSE_VALUE
);
608 /* Hashing routine for EDGE_TO_CASES. */
611 edge_to_cases_hash (const void *p
)
613 edge e
= ((struct edge_to_cases_elt
*)p
)->e
;
615 /* Hash on the edge itself (which is a pointer). */
616 return htab_hash_pointer (e
);
619 /* Equality routine for EDGE_TO_CASES, edges are unique, so testing
620 for equality is just a pointer comparison. */
623 edge_to_cases_eq (const void *p1
, const void *p2
)
625 edge e1
= ((struct edge_to_cases_elt
*)p1
)->e
;
626 edge e2
= ((struct edge_to_cases_elt
*)p2
)->e
;
631 /* Called for each element in the hash table (P) as we delete the
632 edge to cases hash table.
634 Clear all the TREE_CHAINs to prevent problems with copying of
635 SWITCH_EXPRs and structure sharing rules, then free the hash table
639 edge_to_cases_cleanup (void *p
)
641 struct edge_to_cases_elt
*elt
= p
;
644 for (t
= elt
->case_labels
; t
; t
= next
)
646 next
= TREE_CHAIN (t
);
647 TREE_CHAIN (t
) = NULL
;
652 /* Start recording information mapping edges to case labels. */
655 start_recording_case_labels (void)
657 gcc_assert (edge_to_cases
== NULL
);
659 edge_to_cases
= htab_create (37,
662 edge_to_cases_cleanup
);
665 /* Return nonzero if we are recording information for case labels. */
668 recording_case_labels_p (void)
670 return (edge_to_cases
!= NULL
);
673 /* Stop recording information mapping edges to case labels and
674 remove any information we have recorded. */
676 end_recording_case_labels (void)
678 htab_delete (edge_to_cases
);
679 edge_to_cases
= NULL
;
682 /* Record that CASE_LABEL (a CASE_LABEL_EXPR) references edge E. */
685 record_switch_edge (edge e
, tree case_label
)
687 struct edge_to_cases_elt
*elt
;
690 /* Build a hash table element so we can see if E is already
692 elt
= xmalloc (sizeof (struct edge_to_cases_elt
));
694 elt
->case_labels
= case_label
;
696 slot
= htab_find_slot (edge_to_cases
, elt
, INSERT
);
700 /* E was not in the hash table. Install E into the hash table. */
705 /* E was already in the hash table. Free ELT as we do not need it
709 /* Get the entry stored in the hash table. */
710 elt
= (struct edge_to_cases_elt
*) *slot
;
712 /* Add it to the chain of CASE_LABEL_EXPRs referencing E. */
713 TREE_CHAIN (case_label
) = elt
->case_labels
;
714 elt
->case_labels
= case_label
;
718 /* If we are inside a {start,end}_recording_cases block, then return
719 a chain of CASE_LABEL_EXPRs from T which reference E.
721 Otherwise return NULL. */
724 get_cases_for_edge (edge e
, tree t
)
726 struct edge_to_cases_elt elt
, *elt_p
;
731 /* If we are not recording cases, then we do not have CASE_LABEL_EXPR
732 chains available. Return NULL so the caller can detect this case. */
733 if (!recording_case_labels_p ())
738 elt
.case_labels
= NULL
;
739 slot
= htab_find_slot (edge_to_cases
, &elt
, NO_INSERT
);
743 elt_p
= (struct edge_to_cases_elt
*)*slot
;
744 return elt_p
->case_labels
;
747 /* If we did not find E in the hash table, then this must be the first
748 time we have been queried for information about E & T. Add all the
749 elements from T to the hash table then perform the query again. */
751 vec
= SWITCH_LABELS (t
);
752 n
= TREE_VEC_LENGTH (vec
);
753 for (i
= 0; i
< n
; i
++)
755 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
756 basic_block label_bb
= label_to_block (lab
);
757 record_switch_edge (find_edge (e
->src
, label_bb
), TREE_VEC_ELT (vec
, i
));
762 /* Create the edges for a SWITCH_EXPR starting at block BB.
763 At this point, the switch body has been lowered and the
764 SWITCH_LABELS filled in, so this is in effect a multi-way branch. */
767 make_switch_expr_edges (basic_block bb
)
769 tree entry
= last_stmt (bb
);
773 vec
= SWITCH_LABELS (entry
);
774 n
= TREE_VEC_LENGTH (vec
);
776 for (i
= 0; i
< n
; ++i
)
778 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
779 basic_block label_bb
= label_to_block (lab
);
780 make_edge (bb
, label_bb
, 0);
785 /* Return the basic block holding label DEST. */
788 label_to_block (tree dest
)
790 int uid
= LABEL_DECL_UID (dest
);
792 /* We would die hard when faced by an undefined label. Emit a label to
793 the very first basic block. This will hopefully make even the dataflow
794 and undefined variable warnings quite right. */
795 if ((errorcount
|| sorrycount
) && uid
< 0)
797 block_stmt_iterator bsi
= bsi_start (BASIC_BLOCK (0));
800 stmt
= build1 (LABEL_EXPR
, void_type_node
, dest
);
801 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
802 uid
= LABEL_DECL_UID (dest
);
804 return VARRAY_BB (label_to_block_map
, uid
);
808 /* Create edges for a goto statement at block BB. */
811 make_goto_expr_edges (basic_block bb
)
814 basic_block target_bb
;
816 block_stmt_iterator last
= bsi_last (bb
);
818 goto_t
= bsi_stmt (last
);
820 /* If the last statement is not a GOTO (i.e., it is a RETURN_EXPR,
821 CALL_EXPR or MODIFY_EXPR), then the edge is an abnormal edge resulting
822 from a nonlocal goto. */
823 if (TREE_CODE (goto_t
) != GOTO_EXPR
)
825 dest
= error_mark_node
;
830 dest
= GOTO_DESTINATION (goto_t
);
833 /* A GOTO to a local label creates normal edges. */
834 if (simple_goto_p (goto_t
))
836 edge e
= make_edge (bb
, label_to_block (dest
), EDGE_FALLTHRU
);
837 #ifdef USE_MAPPED_LOCATION
838 e
->goto_locus
= EXPR_LOCATION (goto_t
);
840 e
->goto_locus
= EXPR_LOCUS (goto_t
);
846 /* Nothing more to do for nonlocal gotos. */
847 if (TREE_CODE (dest
) == LABEL_DECL
)
850 /* Computed gotos remain. */
853 /* Look for the block starting with the destination label. In the
854 case of a computed goto, make an edge to any label block we find
856 FOR_EACH_BB (target_bb
)
858 block_stmt_iterator bsi
;
860 for (bsi
= bsi_start (target_bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
862 tree target
= bsi_stmt (bsi
);
864 if (TREE_CODE (target
) != LABEL_EXPR
)
868 /* Computed GOTOs. Make an edge to every label block that has
869 been marked as a potential target for a computed goto. */
870 (FORCED_LABEL (LABEL_EXPR_LABEL (target
)) && for_call
== 0)
871 /* Nonlocal GOTO target. Make an edge to every label block
872 that has been marked as a potential target for a nonlocal
874 || (DECL_NONLOCAL (LABEL_EXPR_LABEL (target
)) && for_call
== 1))
876 make_edge (bb
, target_bb
, EDGE_ABNORMAL
);
882 /* Degenerate case of computed goto with no labels. */
883 if (!for_call
&& EDGE_COUNT (bb
->succs
) == 0)
884 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
888 /*---------------------------------------------------------------------------
890 ---------------------------------------------------------------------------*/
892 /* Remove unreachable blocks and other miscellaneous clean up work. */
895 cleanup_tree_cfg (void)
899 timevar_push (TV_TREE_CLEANUP_CFG
);
901 retval
= cleanup_control_flow ();
902 retval
|= delete_unreachable_blocks ();
904 /* cleanup_forwarder_blocks can redirect edges out of SWITCH_EXPRs,
905 which can get expensive. So we want to enable recording of edge
906 to CASE_LABEL_EXPR mappings around the call to
907 cleanup_forwarder_blocks. */
908 start_recording_case_labels ();
909 retval
|= cleanup_forwarder_blocks ();
910 end_recording_case_labels ();
912 #ifdef ENABLE_CHECKING
915 gcc_assert (!cleanup_control_flow ());
916 gcc_assert (!delete_unreachable_blocks ());
917 gcc_assert (!cleanup_forwarder_blocks ());
921 /* Merging the blocks creates no new opportunities for the other
922 optimizations, so do it here. */
923 retval
|= merge_seq_blocks ();
927 #ifdef ENABLE_CHECKING
930 timevar_pop (TV_TREE_CLEANUP_CFG
);
935 /* Cleanup useless labels in basic blocks. This is something we wish
936 to do early because it allows us to group case labels before creating
937 the edges for the CFG, and it speeds up block statement iterators in
939 We only run this pass once, running it more than once is probably not
942 /* A map from basic block index to the leading label of that block. */
943 static tree
*label_for_bb
;
945 /* Callback for for_each_eh_region. Helper for cleanup_dead_labels. */
947 update_eh_label (struct eh_region
*region
)
949 tree old_label
= get_eh_region_tree_label (region
);
953 basic_block bb
= label_to_block (old_label
);
955 /* ??? After optimizing, there may be EH regions with labels
956 that have already been removed from the function body, so
957 there is no basic block for them. */
961 new_label
= label_for_bb
[bb
->index
];
962 set_eh_region_tree_label (region
, new_label
);
966 /* Given LABEL return the first label in the same basic block. */
968 main_block_label (tree label
)
970 basic_block bb
= label_to_block (label
);
972 /* label_to_block possibly inserted undefined label into the chain. */
973 if (!label_for_bb
[bb
->index
])
974 label_for_bb
[bb
->index
] = label
;
975 return label_for_bb
[bb
->index
];
978 /* Cleanup redundant labels. This is a three-step process:
979 1) Find the leading label for each block.
980 2) Redirect all references to labels to the leading labels.
981 3) Cleanup all useless labels. */
984 cleanup_dead_labels (void)
987 label_for_bb
= xcalloc (last_basic_block
, sizeof (tree
));
989 /* Find a suitable label for each block. We use the first user-defined
990 label if there is one, or otherwise just the first label we see. */
993 block_stmt_iterator i
;
995 for (i
= bsi_start (bb
); !bsi_end_p (i
); bsi_next (&i
))
997 tree label
, stmt
= bsi_stmt (i
);
999 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1002 label
= LABEL_EXPR_LABEL (stmt
);
1004 /* If we have not yet seen a label for the current block,
1005 remember this one and see if there are more labels. */
1006 if (! label_for_bb
[bb
->index
])
1008 label_for_bb
[bb
->index
] = label
;
1012 /* If we did see a label for the current block already, but it
1013 is an artificially created label, replace it if the current
1014 label is a user defined label. */
1015 if (! DECL_ARTIFICIAL (label
)
1016 && DECL_ARTIFICIAL (label_for_bb
[bb
->index
]))
1018 label_for_bb
[bb
->index
] = label
;
1024 /* Now redirect all jumps/branches to the selected label.
1025 First do so for each block ending in a control statement. */
1028 tree stmt
= last_stmt (bb
);
1032 switch (TREE_CODE (stmt
))
1036 tree true_branch
, false_branch
;
1038 true_branch
= COND_EXPR_THEN (stmt
);
1039 false_branch
= COND_EXPR_ELSE (stmt
);
1041 GOTO_DESTINATION (true_branch
)
1042 = main_block_label (GOTO_DESTINATION (true_branch
));
1043 GOTO_DESTINATION (false_branch
)
1044 = main_block_label (GOTO_DESTINATION (false_branch
));
1052 tree vec
= SWITCH_LABELS (stmt
);
1053 size_t n
= TREE_VEC_LENGTH (vec
);
1055 /* Replace all destination labels. */
1056 for (i
= 0; i
< n
; ++i
)
1058 tree elt
= TREE_VEC_ELT (vec
, i
);
1059 tree label
= main_block_label (CASE_LABEL (elt
));
1060 CASE_LABEL (elt
) = label
;
1065 /* We have to handle GOTO_EXPRs until they're removed, and we don't
1066 remove them until after we've created the CFG edges. */
1068 if (! computed_goto_p (stmt
))
1070 GOTO_DESTINATION (stmt
)
1071 = main_block_label (GOTO_DESTINATION (stmt
));
1080 for_each_eh_region (update_eh_label
);
1082 /* Finally, purge dead labels. All user-defined labels and labels that
1083 can be the target of non-local gotos are preserved. */
1086 block_stmt_iterator i
;
1087 tree label_for_this_bb
= label_for_bb
[bb
->index
];
1089 if (! label_for_this_bb
)
1092 for (i
= bsi_start (bb
); !bsi_end_p (i
); )
1094 tree label
, stmt
= bsi_stmt (i
);
1096 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1099 label
= LABEL_EXPR_LABEL (stmt
);
1101 if (label
== label_for_this_bb
1102 || ! DECL_ARTIFICIAL (label
)
1103 || DECL_NONLOCAL (label
))
1110 free (label_for_bb
);
1113 /* Look for blocks ending in a multiway branch (a SWITCH_EXPR in GIMPLE),
1114 and scan the sorted vector of cases. Combine the ones jumping to the
1116 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
1119 group_case_labels (void)
1125 tree stmt
= last_stmt (bb
);
1126 if (stmt
&& TREE_CODE (stmt
) == SWITCH_EXPR
)
1128 tree labels
= SWITCH_LABELS (stmt
);
1129 int old_size
= TREE_VEC_LENGTH (labels
);
1130 int i
, j
, new_size
= old_size
;
1131 tree default_case
= TREE_VEC_ELT (labels
, old_size
- 1);
1134 /* The default label is always the last case in a switch
1135 statement after gimplification. */
1136 default_label
= CASE_LABEL (default_case
);
1138 /* Look for possible opportunities to merge cases.
1139 Ignore the last element of the label vector because it
1140 must be the default case. */
1142 while (i
< old_size
- 1)
1144 tree base_case
, base_label
, base_high
, type
;
1145 base_case
= TREE_VEC_ELT (labels
, i
);
1147 gcc_assert (base_case
);
1148 base_label
= CASE_LABEL (base_case
);
1150 /* Discard cases that have the same destination as the
1152 if (base_label
== default_label
)
1154 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1160 type
= TREE_TYPE (CASE_LOW (base_case
));
1161 base_high
= CASE_HIGH (base_case
) ?
1162 CASE_HIGH (base_case
) : CASE_LOW (base_case
);
1164 /* Try to merge case labels. Break out when we reach the end
1165 of the label vector or when we cannot merge the next case
1166 label with the current one. */
1167 while (i
< old_size
- 1)
1169 tree merge_case
= TREE_VEC_ELT (labels
, i
);
1170 tree merge_label
= CASE_LABEL (merge_case
);
1171 tree t
= int_const_binop (PLUS_EXPR
, base_high
,
1172 integer_one_node
, 1);
1174 /* Merge the cases if they jump to the same place,
1175 and their ranges are consecutive. */
1176 if (merge_label
== base_label
1177 && tree_int_cst_equal (CASE_LOW (merge_case
), t
))
1179 base_high
= CASE_HIGH (merge_case
) ?
1180 CASE_HIGH (merge_case
) : CASE_LOW (merge_case
);
1181 CASE_HIGH (base_case
) = base_high
;
1182 TREE_VEC_ELT (labels
, i
) = NULL_TREE
;
1191 /* Compress the case labels in the label vector, and adjust the
1192 length of the vector. */
1193 for (i
= 0, j
= 0; i
< new_size
; i
++)
1195 while (! TREE_VEC_ELT (labels
, j
))
1197 TREE_VEC_ELT (labels
, i
) = TREE_VEC_ELT (labels
, j
++);
1199 TREE_VEC_LENGTH (labels
) = new_size
;
1204 /* Checks whether we can merge block B into block A. */
1207 tree_can_merge_blocks_p (basic_block a
, basic_block b
)
1210 block_stmt_iterator bsi
;
1212 if (EDGE_COUNT (a
->succs
) != 1)
1215 if (EDGE_SUCC (a
, 0)->flags
& EDGE_ABNORMAL
)
1218 if (EDGE_SUCC (a
, 0)->dest
!= b
)
1221 if (EDGE_COUNT (b
->preds
) > 1)
1224 if (b
== EXIT_BLOCK_PTR
)
1227 /* If A ends by a statement causing exceptions or something similar, we
1228 cannot merge the blocks. */
1229 stmt
= last_stmt (a
);
1230 if (stmt
&& stmt_ends_bb_p (stmt
))
1233 /* Do not allow a block with only a non-local label to be merged. */
1234 if (stmt
&& TREE_CODE (stmt
) == LABEL_EXPR
1235 && DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
1238 /* There may be no phi nodes at the start of b. Most of these degenerate
1239 phi nodes should be cleaned up by kill_redundant_phi_nodes. */
1243 /* Do not remove user labels. */
1244 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
); bsi_next (&bsi
))
1246 stmt
= bsi_stmt (bsi
);
1247 if (TREE_CODE (stmt
) != LABEL_EXPR
)
1249 if (!DECL_ARTIFICIAL (LABEL_EXPR_LABEL (stmt
)))
1257 /* Merge block B into block A. */
1260 tree_merge_blocks (basic_block a
, basic_block b
)
1262 block_stmt_iterator bsi
;
1263 tree_stmt_iterator last
;
1266 fprintf (dump_file
, "Merging blocks %d and %d\n", a
->index
, b
->index
);
1268 /* Ensure that B follows A. */
1269 move_block_after (b
, a
);
1271 gcc_assert (EDGE_SUCC (a
, 0)->flags
& EDGE_FALLTHRU
);
1272 gcc_assert (!last_stmt (a
) || !stmt_ends_bb_p (last_stmt (a
)));
1274 /* Remove labels from B and set bb_for_stmt to A for other statements. */
1275 for (bsi
= bsi_start (b
); !bsi_end_p (bsi
);)
1277 if (TREE_CODE (bsi_stmt (bsi
)) == LABEL_EXPR
)
1281 set_bb_for_stmt (bsi_stmt (bsi
), a
);
1286 /* Merge the chains. */
1287 last
= tsi_last (a
->stmt_list
);
1288 tsi_link_after (&last
, b
->stmt_list
, TSI_NEW_STMT
);
1289 b
->stmt_list
= NULL
;
1293 /* Walk the function tree removing unnecessary statements.
1295 * Empty statement nodes are removed
1297 * Unnecessary TRY_FINALLY and TRY_CATCH blocks are removed
1299 * Unnecessary COND_EXPRs are removed
1301 * Some unnecessary BIND_EXPRs are removed
1303 Clearly more work could be done. The trick is doing the analysis
1304 and removal fast enough to be a net improvement in compile times.
1306 Note that when we remove a control structure such as a COND_EXPR
1307 BIND_EXPR, or TRY block, we will need to repeat this optimization pass
1308 to ensure we eliminate all the useless code. */
1319 static void remove_useless_stmts_1 (tree
*, struct rus_data
*);
1322 remove_useless_stmts_warn_notreached (tree stmt
)
1324 if (EXPR_HAS_LOCATION (stmt
))
1326 location_t loc
= EXPR_LOCATION (stmt
);
1327 if (LOCATION_LINE (loc
) > 0)
1329 warning ("%Hwill never be executed", &loc
);
1334 switch (TREE_CODE (stmt
))
1336 case STATEMENT_LIST
:
1338 tree_stmt_iterator i
;
1339 for (i
= tsi_start (stmt
); !tsi_end_p (i
); tsi_next (&i
))
1340 if (remove_useless_stmts_warn_notreached (tsi_stmt (i
)))
1346 if (remove_useless_stmts_warn_notreached (COND_EXPR_COND (stmt
)))
1348 if (remove_useless_stmts_warn_notreached (COND_EXPR_THEN (stmt
)))
1350 if (remove_useless_stmts_warn_notreached (COND_EXPR_ELSE (stmt
)))
1354 case TRY_FINALLY_EXPR
:
1355 case TRY_CATCH_EXPR
:
1356 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 0)))
1358 if (remove_useless_stmts_warn_notreached (TREE_OPERAND (stmt
, 1)))
1363 return remove_useless_stmts_warn_notreached (CATCH_BODY (stmt
));
1364 case EH_FILTER_EXPR
:
1365 return remove_useless_stmts_warn_notreached (EH_FILTER_FAILURE (stmt
));
1367 return remove_useless_stmts_warn_notreached (BIND_EXPR_BLOCK (stmt
));
1370 /* Not a live container. */
1378 remove_useless_stmts_cond (tree
*stmt_p
, struct rus_data
*data
)
1380 tree then_clause
, else_clause
, cond
;
1381 bool save_has_label
, then_has_label
, else_has_label
;
1383 save_has_label
= data
->has_label
;
1384 data
->has_label
= false;
1385 data
->last_goto
= NULL
;
1387 remove_useless_stmts_1 (&COND_EXPR_THEN (*stmt_p
), data
);
1389 then_has_label
= data
->has_label
;
1390 data
->has_label
= false;
1391 data
->last_goto
= NULL
;
1393 remove_useless_stmts_1 (&COND_EXPR_ELSE (*stmt_p
), data
);
1395 else_has_label
= data
->has_label
;
1396 data
->has_label
= save_has_label
| then_has_label
| else_has_label
;
1398 then_clause
= COND_EXPR_THEN (*stmt_p
);
1399 else_clause
= COND_EXPR_ELSE (*stmt_p
);
1400 cond
= fold (COND_EXPR_COND (*stmt_p
));
1402 /* If neither arm does anything at all, we can remove the whole IF. */
1403 if (!TREE_SIDE_EFFECTS (then_clause
) && !TREE_SIDE_EFFECTS (else_clause
))
1405 *stmt_p
= build_empty_stmt ();
1406 data
->repeat
= true;
1409 /* If there are no reachable statements in an arm, then we can
1410 zap the entire conditional. */
1411 else if (integer_nonzerop (cond
) && !else_has_label
)
1413 if (warn_notreached
)
1414 remove_useless_stmts_warn_notreached (else_clause
);
1415 *stmt_p
= then_clause
;
1416 data
->repeat
= true;
1418 else if (integer_zerop (cond
) && !then_has_label
)
1420 if (warn_notreached
)
1421 remove_useless_stmts_warn_notreached (then_clause
);
1422 *stmt_p
= else_clause
;
1423 data
->repeat
= true;
1426 /* Check a couple of simple things on then/else with single stmts. */
1429 tree then_stmt
= expr_only (then_clause
);
1430 tree else_stmt
= expr_only (else_clause
);
1432 /* Notice branches to a common destination. */
1433 if (then_stmt
&& else_stmt
1434 && TREE_CODE (then_stmt
) == GOTO_EXPR
1435 && TREE_CODE (else_stmt
) == GOTO_EXPR
1436 && (GOTO_DESTINATION (then_stmt
) == GOTO_DESTINATION (else_stmt
)))
1438 *stmt_p
= then_stmt
;
1439 data
->repeat
= true;
1442 /* If the THEN/ELSE clause merely assigns a value to a variable or
1443 parameter which is already known to contain that value, then
1444 remove the useless THEN/ELSE clause. */
1445 else if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1448 && TREE_CODE (else_stmt
) == MODIFY_EXPR
1449 && TREE_OPERAND (else_stmt
, 0) == cond
1450 && integer_zerop (TREE_OPERAND (else_stmt
, 1)))
1451 COND_EXPR_ELSE (*stmt_p
) = alloc_stmt_list ();
1453 else if ((TREE_CODE (cond
) == EQ_EXPR
|| TREE_CODE (cond
) == NE_EXPR
)
1454 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1455 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1456 && TREE_CONSTANT (TREE_OPERAND (cond
, 1)))
1458 tree stmt
= (TREE_CODE (cond
) == EQ_EXPR
1459 ? then_stmt
: else_stmt
);
1460 tree
*location
= (TREE_CODE (cond
) == EQ_EXPR
1461 ? &COND_EXPR_THEN (*stmt_p
)
1462 : &COND_EXPR_ELSE (*stmt_p
));
1465 && TREE_CODE (stmt
) == MODIFY_EXPR
1466 && TREE_OPERAND (stmt
, 0) == TREE_OPERAND (cond
, 0)
1467 && TREE_OPERAND (stmt
, 1) == TREE_OPERAND (cond
, 1))
1468 *location
= alloc_stmt_list ();
1472 /* Protect GOTOs in the arm of COND_EXPRs from being removed. They
1473 would be re-introduced during lowering. */
1474 data
->last_goto
= NULL
;
1479 remove_useless_stmts_tf (tree
*stmt_p
, struct rus_data
*data
)
1481 bool save_may_branch
, save_may_throw
;
1482 bool this_may_branch
, this_may_throw
;
1484 /* Collect may_branch and may_throw information for the body only. */
1485 save_may_branch
= data
->may_branch
;
1486 save_may_throw
= data
->may_throw
;
1487 data
->may_branch
= false;
1488 data
->may_throw
= false;
1489 data
->last_goto
= NULL
;
1491 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1493 this_may_branch
= data
->may_branch
;
1494 this_may_throw
= data
->may_throw
;
1495 data
->may_branch
|= save_may_branch
;
1496 data
->may_throw
|= save_may_throw
;
1497 data
->last_goto
= NULL
;
1499 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1501 /* If the body is empty, then we can emit the FINALLY block without
1502 the enclosing TRY_FINALLY_EXPR. */
1503 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 0)))
1505 *stmt_p
= TREE_OPERAND (*stmt_p
, 1);
1506 data
->repeat
= true;
1509 /* If the handler is empty, then we can emit the TRY block without
1510 the enclosing TRY_FINALLY_EXPR. */
1511 else if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1513 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1514 data
->repeat
= true;
1517 /* If the body neither throws, nor branches, then we can safely
1518 string the TRY and FINALLY blocks together. */
1519 else if (!this_may_branch
&& !this_may_throw
)
1521 tree stmt
= *stmt_p
;
1522 *stmt_p
= TREE_OPERAND (stmt
, 0);
1523 append_to_statement_list (TREE_OPERAND (stmt
, 1), stmt_p
);
1524 data
->repeat
= true;
1530 remove_useless_stmts_tc (tree
*stmt_p
, struct rus_data
*data
)
1532 bool save_may_throw
, this_may_throw
;
1533 tree_stmt_iterator i
;
1536 /* Collect may_throw information for the body only. */
1537 save_may_throw
= data
->may_throw
;
1538 data
->may_throw
= false;
1539 data
->last_goto
= NULL
;
1541 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 0), data
);
1543 this_may_throw
= data
->may_throw
;
1544 data
->may_throw
= save_may_throw
;
1546 /* If the body cannot throw, then we can drop the entire TRY_CATCH_EXPR. */
1547 if (!this_may_throw
)
1549 if (warn_notreached
)
1550 remove_useless_stmts_warn_notreached (TREE_OPERAND (*stmt_p
, 1));
1551 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1552 data
->repeat
= true;
1556 /* Process the catch clause specially. We may be able to tell that
1557 no exceptions propagate past this point. */
1559 this_may_throw
= true;
1560 i
= tsi_start (TREE_OPERAND (*stmt_p
, 1));
1561 stmt
= tsi_stmt (i
);
1562 data
->last_goto
= NULL
;
1564 switch (TREE_CODE (stmt
))
1567 for (; !tsi_end_p (i
); tsi_next (&i
))
1569 stmt
= tsi_stmt (i
);
1570 /* If we catch all exceptions, then the body does not
1571 propagate exceptions past this point. */
1572 if (CATCH_TYPES (stmt
) == NULL
)
1573 this_may_throw
= false;
1574 data
->last_goto
= NULL
;
1575 remove_useless_stmts_1 (&CATCH_BODY (stmt
), data
);
1579 case EH_FILTER_EXPR
:
1580 if (EH_FILTER_MUST_NOT_THROW (stmt
))
1581 this_may_throw
= false;
1582 else if (EH_FILTER_TYPES (stmt
) == NULL
)
1583 this_may_throw
= false;
1584 remove_useless_stmts_1 (&EH_FILTER_FAILURE (stmt
), data
);
1588 /* Otherwise this is a cleanup. */
1589 remove_useless_stmts_1 (&TREE_OPERAND (*stmt_p
, 1), data
);
1591 /* If the cleanup is empty, then we can emit the TRY block without
1592 the enclosing TRY_CATCH_EXPR. */
1593 if (!TREE_SIDE_EFFECTS (TREE_OPERAND (*stmt_p
, 1)))
1595 *stmt_p
= TREE_OPERAND (*stmt_p
, 0);
1596 data
->repeat
= true;
1600 data
->may_throw
|= this_may_throw
;
1605 remove_useless_stmts_bind (tree
*stmt_p
, struct rus_data
*data
)
1609 /* First remove anything underneath the BIND_EXPR. */
1610 remove_useless_stmts_1 (&BIND_EXPR_BODY (*stmt_p
), data
);
1612 /* If the BIND_EXPR has no variables, then we can pull everything
1613 up one level and remove the BIND_EXPR, unless this is the toplevel
1614 BIND_EXPR for the current function or an inlined function.
1616 When this situation occurs we will want to apply this
1617 optimization again. */
1618 block
= BIND_EXPR_BLOCK (*stmt_p
);
1619 if (BIND_EXPR_VARS (*stmt_p
) == NULL_TREE
1620 && *stmt_p
!= DECL_SAVED_TREE (current_function_decl
)
1622 || ! BLOCK_ABSTRACT_ORIGIN (block
)
1623 || (TREE_CODE (BLOCK_ABSTRACT_ORIGIN (block
))
1626 *stmt_p
= BIND_EXPR_BODY (*stmt_p
);
1627 data
->repeat
= true;
1633 remove_useless_stmts_goto (tree
*stmt_p
, struct rus_data
*data
)
1635 tree dest
= GOTO_DESTINATION (*stmt_p
);
1637 data
->may_branch
= true;
1638 data
->last_goto
= NULL
;
1640 /* Record the last goto expr, so that we can delete it if unnecessary. */
1641 if (TREE_CODE (dest
) == LABEL_DECL
)
1642 data
->last_goto
= stmt_p
;
1647 remove_useless_stmts_label (tree
*stmt_p
, struct rus_data
*data
)
1649 tree label
= LABEL_EXPR_LABEL (*stmt_p
);
1651 data
->has_label
= true;
1653 /* We do want to jump across non-local label receiver code. */
1654 if (DECL_NONLOCAL (label
))
1655 data
->last_goto
= NULL
;
1657 else if (data
->last_goto
&& GOTO_DESTINATION (*data
->last_goto
) == label
)
1659 *data
->last_goto
= build_empty_stmt ();
1660 data
->repeat
= true;
1663 /* ??? Add something here to delete unused labels. */
1667 /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
1668 decl. This allows us to eliminate redundant or useless
1669 calls to "const" functions.
1671 Gimplifier already does the same operation, but we may notice functions
1672 being const and pure once their calls has been gimplified, so we need
1673 to update the flag. */
1676 update_call_expr_flags (tree call
)
1678 tree decl
= get_callee_fndecl (call
);
1681 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1682 TREE_SIDE_EFFECTS (call
) = 0;
1683 if (TREE_NOTHROW (decl
))
1684 TREE_NOTHROW (call
) = 1;
1688 /* T is CALL_EXPR. Set current_function_calls_* flags. */
1691 notice_special_calls (tree t
)
1693 int flags
= call_expr_flags (t
);
1695 if (flags
& ECF_MAY_BE_ALLOCA
)
1696 current_function_calls_alloca
= true;
1697 if (flags
& ECF_RETURNS_TWICE
)
1698 current_function_calls_setjmp
= true;
1702 /* Clear flags set by notice_special_calls. Used by dead code removal
1703 to update the flags. */
1706 clear_special_calls (void)
1708 current_function_calls_alloca
= false;
1709 current_function_calls_setjmp
= false;
1714 remove_useless_stmts_1 (tree
*tp
, struct rus_data
*data
)
1718 switch (TREE_CODE (t
))
1721 remove_useless_stmts_cond (tp
, data
);
1724 case TRY_FINALLY_EXPR
:
1725 remove_useless_stmts_tf (tp
, data
);
1728 case TRY_CATCH_EXPR
:
1729 remove_useless_stmts_tc (tp
, data
);
1733 remove_useless_stmts_bind (tp
, data
);
1737 remove_useless_stmts_goto (tp
, data
);
1741 remove_useless_stmts_label (tp
, data
);
1746 data
->last_goto
= NULL
;
1747 data
->may_branch
= true;
1752 data
->last_goto
= NULL
;
1753 notice_special_calls (t
);
1754 update_call_expr_flags (t
);
1755 if (tree_could_throw_p (t
))
1756 data
->may_throw
= true;
1760 data
->last_goto
= NULL
;
1762 op
= get_call_expr_in (t
);
1765 update_call_expr_flags (op
);
1766 notice_special_calls (op
);
1768 if (tree_could_throw_p (t
))
1769 data
->may_throw
= true;
1772 case STATEMENT_LIST
:
1774 tree_stmt_iterator i
= tsi_start (t
);
1775 while (!tsi_end_p (i
))
1778 if (IS_EMPTY_STMT (t
))
1784 remove_useless_stmts_1 (tsi_stmt_ptr (i
), data
);
1787 if (TREE_CODE (t
) == STATEMENT_LIST
)
1789 tsi_link_before (&i
, t
, TSI_SAME_STMT
);
1799 data
->last_goto
= NULL
;
1803 data
->last_goto
= NULL
;
1809 remove_useless_stmts (void)
1811 struct rus_data data
;
1813 clear_special_calls ();
1817 memset (&data
, 0, sizeof (data
));
1818 remove_useless_stmts_1 (&DECL_SAVED_TREE (current_function_decl
), &data
);
1820 while (data
.repeat
);
1824 struct tree_opt_pass pass_remove_useless_stmts
=
1826 "useless", /* name */
1828 remove_useless_stmts
, /* execute */
1831 0, /* static_pass_number */
1833 PROP_gimple_any
, /* properties_required */
1834 0, /* properties_provided */
1835 0, /* properties_destroyed */
1836 0, /* todo_flags_start */
1837 TODO_dump_func
, /* todo_flags_finish */
1842 /* Remove obviously useless statements in basic block BB. */
1845 cfg_remove_useless_stmts_bb (basic_block bb
)
1847 block_stmt_iterator bsi
;
1848 tree stmt
= NULL_TREE
;
1849 tree cond
, var
= NULL_TREE
, val
= NULL_TREE
;
1850 struct var_ann_d
*ann
;
1852 /* Check whether we come here from a condition, and if so, get the
1854 if (EDGE_COUNT (bb
->preds
) != 1
1855 || !(EDGE_PRED (bb
, 0)->flags
& (EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
1858 cond
= COND_EXPR_COND (last_stmt (EDGE_PRED (bb
, 0)->src
));
1860 if (TREE_CODE (cond
) == VAR_DECL
|| TREE_CODE (cond
) == PARM_DECL
)
1863 val
= (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
1864 ? boolean_false_node
: boolean_true_node
);
1866 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
1867 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1868 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
))
1870 var
= TREE_OPERAND (cond
, 0);
1871 val
= (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
1872 ? boolean_true_node
: boolean_false_node
);
1876 if (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
)
1877 cond
= invert_truthvalue (cond
);
1878 if (TREE_CODE (cond
) == EQ_EXPR
1879 && (TREE_CODE (TREE_OPERAND (cond
, 0)) == VAR_DECL
1880 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PARM_DECL
)
1881 && (TREE_CODE (TREE_OPERAND (cond
, 1)) == VAR_DECL
1882 || TREE_CODE (TREE_OPERAND (cond
, 1)) == PARM_DECL
1883 || TREE_CONSTANT (TREE_OPERAND (cond
, 1))))
1885 var
= TREE_OPERAND (cond
, 0);
1886 val
= TREE_OPERAND (cond
, 1);
1892 /* Only work for normal local variables. */
1893 ann
= var_ann (var
);
1896 || TREE_ADDRESSABLE (var
))
1899 if (! TREE_CONSTANT (val
))
1901 ann
= var_ann (val
);
1904 || TREE_ADDRESSABLE (val
))
1908 /* Ignore floating point variables, since comparison behaves weird for
1910 if (FLOAT_TYPE_P (TREE_TYPE (var
)))
1913 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
);)
1915 stmt
= bsi_stmt (bsi
);
1917 /* If the THEN/ELSE clause merely assigns a value to a variable/parameter
1918 which is already known to contain that value, then remove the useless
1919 THEN/ELSE clause. */
1920 if (TREE_CODE (stmt
) == MODIFY_EXPR
1921 && TREE_OPERAND (stmt
, 0) == var
1922 && operand_equal_p (val
, TREE_OPERAND (stmt
, 1), 0))
1928 /* Invalidate the var if we encounter something that could modify it.
1929 Likewise for the value it was previously set to. Note that we only
1930 consider values that are either a VAR_DECL or PARM_DECL so we
1931 can test for conflict very simply. */
1932 if (TREE_CODE (stmt
) == ASM_EXPR
1933 || (TREE_CODE (stmt
) == MODIFY_EXPR
1934 && (TREE_OPERAND (stmt
, 0) == var
1935 || TREE_OPERAND (stmt
, 0) == val
)))
1943 /* A CFG-aware version of remove_useless_stmts. */
1946 cfg_remove_useless_stmts (void)
1950 #ifdef ENABLE_CHECKING
1951 verify_flow_info ();
1956 cfg_remove_useless_stmts_bb (bb
);
1961 /* Remove PHI nodes associated with basic block BB and all edges out of BB. */
1964 remove_phi_nodes_and_edges_for_unreachable_block (basic_block bb
)
1968 /* Since this block is no longer reachable, we can just delete all
1969 of its PHI nodes. */
1970 phi
= phi_nodes (bb
);
1973 tree next
= PHI_CHAIN (phi
);
1974 remove_phi_node (phi
, NULL_TREE
, bb
);
1978 /* Remove edges to BB's successors. */
1979 while (EDGE_COUNT (bb
->succs
) > 0)
1980 remove_edge (EDGE_SUCC (bb
, 0));
1984 /* Remove statements of basic block BB. */
1987 remove_bb (basic_block bb
)
1989 block_stmt_iterator i
;
1990 source_locus loc
= 0;
1994 fprintf (dump_file
, "Removing basic block %d\n", bb
->index
);
1995 if (dump_flags
& TDF_DETAILS
)
1997 dump_bb (bb
, dump_file
, 0);
1998 fprintf (dump_file
, "\n");
2002 /* Remove all the instructions in the block. */
2003 for (i
= bsi_start (bb
); !bsi_end_p (i
);)
2005 tree stmt
= bsi_stmt (i
);
2006 if (TREE_CODE (stmt
) == LABEL_EXPR
2007 && FORCED_LABEL (LABEL_EXPR_LABEL (stmt
)))
2009 basic_block new_bb
= bb
->prev_bb
;
2010 block_stmt_iterator new_bsi
= bsi_start (new_bb
);
2013 bsi_insert_before (&new_bsi
, stmt
, BSI_NEW_STMT
);
2017 release_defs (stmt
);
2019 set_bb_for_stmt (stmt
, NULL
);
2023 /* Don't warn for removed gotos. Gotos are often removed due to
2024 jump threading, thus resulting in bogus warnings. Not great,
2025 since this way we lose warnings for gotos in the original
2026 program that are indeed unreachable. */
2027 if (TREE_CODE (stmt
) != GOTO_EXPR
&& EXPR_HAS_LOCATION (stmt
) && !loc
)
2031 #ifdef USE_MAPPED_LOCATION
2032 t
= EXPR_LOCATION (stmt
);
2034 t
= EXPR_LOCUS (stmt
);
2036 if (t
&& LOCATION_LINE (*t
) > 0)
2041 /* If requested, give a warning that the first statement in the
2042 block is unreachable. We walk statements backwards in the
2043 loop above, so the last statement we process is the first statement
2045 if (warn_notreached
&& loc
)
2046 #ifdef USE_MAPPED_LOCATION
2047 warning ("%Hwill never be executed", &loc
);
2049 warning ("%Hwill never be executed", loc
);
2052 remove_phi_nodes_and_edges_for_unreachable_block (bb
);
2055 /* Try to remove superfluous control structures. */
2058 cleanup_control_flow (void)
2061 block_stmt_iterator bsi
;
2062 bool retval
= false;
2067 bsi
= bsi_last (bb
);
2069 if (bsi_end_p (bsi
))
2072 stmt
= bsi_stmt (bsi
);
2073 if (TREE_CODE (stmt
) == COND_EXPR
2074 || TREE_CODE (stmt
) == SWITCH_EXPR
)
2075 retval
|= cleanup_control_expr_graph (bb
, bsi
);
2077 /* Check for indirect calls that have been turned into
2079 call
= get_call_expr_in (stmt
);
2081 && (call_expr_flags (call
) & ECF_NORETURN
) != 0
2082 && remove_fallthru_edge (bb
->succs
))
2084 free_dominance_info (CDI_DOMINATORS
);
2092 /* Disconnect an unreachable block in the control expression starting
2096 cleanup_control_expr_graph (basic_block bb
, block_stmt_iterator bsi
)
2099 bool retval
= false;
2100 tree expr
= bsi_stmt (bsi
), val
;
2102 if (EDGE_COUNT (bb
->succs
) > 1)
2107 switch (TREE_CODE (expr
))
2110 val
= COND_EXPR_COND (expr
);
2114 val
= SWITCH_COND (expr
);
2115 if (TREE_CODE (val
) != INTEGER_CST
)
2123 taken_edge
= find_taken_edge (bb
, val
);
2127 /* Remove all the edges except the one that is always executed. */
2128 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
2130 if (e
!= taken_edge
)
2132 taken_edge
->probability
+= e
->probability
;
2133 taken_edge
->count
+= e
->count
;
2140 if (taken_edge
->probability
> REG_BR_PROB_BASE
)
2141 taken_edge
->probability
= REG_BR_PROB_BASE
;
2144 taken_edge
= EDGE_SUCC (bb
, 0);
2147 taken_edge
->flags
= EDGE_FALLTHRU
;
2149 /* We removed some paths from the cfg. */
2150 free_dominance_info (CDI_DOMINATORS
);
2155 /* Remove any fallthru edge from EV. Return true if an edge was removed. */
2158 remove_fallthru_edge (VEC(edge
) *ev
)
2163 FOR_EACH_EDGE (e
, ei
, ev
)
2164 if ((e
->flags
& EDGE_FALLTHRU
) != 0)
2172 /* Given a basic block BB ending with COND_EXPR or SWITCH_EXPR, and a
2173 predicate VAL, return the edge that will be taken out of the block.
2174 If VAL does not match a unique edge, NULL is returned. */
2177 find_taken_edge (basic_block bb
, tree val
)
2181 stmt
= last_stmt (bb
);
2184 gcc_assert (is_ctrl_stmt (stmt
));
2187 /* If VAL is a predicate of the form N RELOP N, where N is an
2188 SSA_NAME, we can usually determine its truth value. */
2189 if (COMPARISON_CLASS_P (val
))
2192 /* If VAL is not a constant, we can't determine which edge might
2194 if (!really_constant_p (val
))
2197 if (TREE_CODE (stmt
) == COND_EXPR
)
2198 return find_taken_edge_cond_expr (bb
, val
);
2200 if (TREE_CODE (stmt
) == SWITCH_EXPR
)
2201 return find_taken_edge_switch_expr (bb
, val
);
2207 /* Given a constant value VAL and the entry block BB to a COND_EXPR
2208 statement, determine which of the two edges will be taken out of the
2209 block. Return NULL if either edge may be taken. */
2212 find_taken_edge_cond_expr (basic_block bb
, tree val
)
2214 edge true_edge
, false_edge
;
2216 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
2218 /* Otherwise, try to determine which branch of the if() will be taken.
2219 If VAL is a constant but it can't be reduced to a 0 or a 1, then
2220 we don't really know which edge will be taken at runtime. This
2221 may happen when comparing addresses (e.g., if (&var1 == 4)). */
2222 if (integer_nonzerop (val
))
2224 else if (integer_zerop (val
))
2231 /* Given a constant value VAL and the entry block BB to a SWITCH_EXPR
2232 statement, determine which edge will be taken out of the block. Return
2233 NULL if any edge may be taken. */
2236 find_taken_edge_switch_expr (basic_block bb
, tree val
)
2238 tree switch_expr
, taken_case
;
2239 basic_block dest_bb
;
2242 if (TREE_CODE (val
) != INTEGER_CST
)
2245 switch_expr
= last_stmt (bb
);
2246 taken_case
= find_case_label_for_value (switch_expr
, val
);
2247 dest_bb
= label_to_block (CASE_LABEL (taken_case
));
2249 e
= find_edge (bb
, dest_bb
);
2255 /* Return the CASE_LABEL_EXPR that SWITCH_EXPR will take for VAL.
2256 We can make optimal use here of the fact that the case labels are
2257 sorted: We can do a binary search for a case matching VAL. */
2260 find_case_label_for_value (tree switch_expr
, tree val
)
2262 tree vec
= SWITCH_LABELS (switch_expr
);
2263 size_t low
, high
, n
= TREE_VEC_LENGTH (vec
);
2264 tree default_case
= TREE_VEC_ELT (vec
, n
- 1);
2266 for (low
= -1, high
= n
- 1; high
- low
> 1; )
2268 size_t i
= (high
+ low
) / 2;
2269 tree t
= TREE_VEC_ELT (vec
, i
);
2272 /* Cache the result of comparing CASE_LOW and val. */
2273 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
2280 if (CASE_HIGH (t
) == NULL
)
2282 /* A singe-valued case label. */
2288 /* A case range. We can only handle integer ranges. */
2289 if (cmp
<= 0 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
2294 return default_case
;
2298 /* If all the PHI nodes in DEST have alternatives for E1 and E2 and
2299 those alternatives are equal in each of the PHI nodes, then return
2300 true, else return false. */
2303 phi_alternatives_equal (basic_block dest
, edge e1
, edge e2
)
2305 int n1
= e1
->dest_idx
;
2306 int n2
= e2
->dest_idx
;
2309 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
2311 tree val1
= PHI_ARG_DEF (phi
, n1
);
2312 tree val2
= PHI_ARG_DEF (phi
, n2
);
2314 gcc_assert (val1
!= NULL_TREE
);
2315 gcc_assert (val2
!= NULL_TREE
);
2317 if (!operand_equal_for_phi_arg_p (val1
, val2
))
2325 /*---------------------------------------------------------------------------
2327 ---------------------------------------------------------------------------*/
2329 /* Dump tree-specific information of block BB to file OUTF. */
2332 tree_dump_bb (basic_block bb
, FILE *outf
, int indent
)
2334 dump_generic_bb (outf
, bb
, indent
, TDF_VOPS
);
2338 /* Dump a basic block on stderr. */
2341 debug_tree_bb (basic_block bb
)
2343 dump_bb (bb
, stderr
, 0);
2347 /* Dump basic block with index N on stderr. */
2350 debug_tree_bb_n (int n
)
2352 debug_tree_bb (BASIC_BLOCK (n
));
2353 return BASIC_BLOCK (n
);
2357 /* Dump the CFG on stderr.
2359 FLAGS are the same used by the tree dumping functions
2360 (see TDF_* in tree.h). */
2363 debug_tree_cfg (int flags
)
2365 dump_tree_cfg (stderr
, flags
);
2369 /* Dump the program showing basic block boundaries on the given FILE.
2371 FLAGS are the same used by the tree dumping functions (see TDF_* in
2375 dump_tree_cfg (FILE *file
, int flags
)
2377 if (flags
& TDF_DETAILS
)
2379 const char *funcname
2380 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2383 fprintf (file
, ";; Function %s\n\n", funcname
);
2384 fprintf (file
, ";; \n%d basic blocks, %d edges, last basic block %d.\n\n",
2385 n_basic_blocks
, n_edges
, last_basic_block
);
2387 brief_dump_cfg (file
);
2388 fprintf (file
, "\n");
2391 if (flags
& TDF_STATS
)
2392 dump_cfg_stats (file
);
2394 dump_function_to_file (current_function_decl
, file
, flags
| TDF_BLOCKS
);
2398 /* Dump CFG statistics on FILE. */
2401 dump_cfg_stats (FILE *file
)
2403 static long max_num_merged_labels
= 0;
2404 unsigned long size
, total
= 0;
2407 const char * const fmt_str
= "%-30s%-13s%12s\n";
2408 const char * const fmt_str_1
= "%-30s%13d%11lu%c\n";
2409 const char * const fmt_str_3
= "%-43s%11lu%c\n";
2410 const char *funcname
2411 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2414 fprintf (file
, "\nCFG Statistics for %s\n\n", funcname
);
2416 fprintf (file
, "---------------------------------------------------------\n");
2417 fprintf (file
, fmt_str
, "", " Number of ", "Memory");
2418 fprintf (file
, fmt_str
, "", " instances ", "used ");
2419 fprintf (file
, "---------------------------------------------------------\n");
2421 size
= n_basic_blocks
* sizeof (struct basic_block_def
);
2423 fprintf (file
, fmt_str_1
, "Basic blocks", n_basic_blocks
,
2424 SCALE (size
), LABEL (size
));
2428 n_edges
+= EDGE_COUNT (bb
->succs
);
2429 size
= n_edges
* sizeof (struct edge_def
);
2431 fprintf (file
, fmt_str_1
, "Edges", n_edges
, SCALE (size
), LABEL (size
));
2433 size
= n_basic_blocks
* sizeof (struct bb_ann_d
);
2435 fprintf (file
, fmt_str_1
, "Basic block annotations", n_basic_blocks
,
2436 SCALE (size
), LABEL (size
));
2438 fprintf (file
, "---------------------------------------------------------\n");
2439 fprintf (file
, fmt_str_3
, "Total memory used by CFG data", SCALE (total
),
2441 fprintf (file
, "---------------------------------------------------------\n");
2442 fprintf (file
, "\n");
2444 if (cfg_stats
.num_merged_labels
> max_num_merged_labels
)
2445 max_num_merged_labels
= cfg_stats
.num_merged_labels
;
2447 fprintf (file
, "Coalesced label blocks: %ld (Max so far: %ld)\n",
2448 cfg_stats
.num_merged_labels
, max_num_merged_labels
);
2450 fprintf (file
, "\n");
2454 /* Dump CFG statistics on stderr. Keep extern so that it's always
2455 linked in the final executable. */
2458 debug_cfg_stats (void)
2460 dump_cfg_stats (stderr
);
2464 /* Dump the flowgraph to a .vcg FILE. */
2467 tree_cfg2vcg (FILE *file
)
2472 const char *funcname
2473 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
2475 /* Write the file header. */
2476 fprintf (file
, "graph: { title: \"%s\"\n", funcname
);
2477 fprintf (file
, "node: { title: \"ENTRY\" label: \"ENTRY\" }\n");
2478 fprintf (file
, "node: { title: \"EXIT\" label: \"EXIT\" }\n");
2480 /* Write blocks and edges. */
2481 FOR_EACH_EDGE (e
, ei
, ENTRY_BLOCK_PTR
->succs
)
2483 fprintf (file
, "edge: { sourcename: \"ENTRY\" targetname: \"%d\"",
2486 if (e
->flags
& EDGE_FAKE
)
2487 fprintf (file
, " linestyle: dotted priority: 10");
2489 fprintf (file
, " linestyle: solid priority: 100");
2491 fprintf (file
, " }\n");
2497 enum tree_code head_code
, end_code
;
2498 const char *head_name
, *end_name
;
2501 tree first
= first_stmt (bb
);
2502 tree last
= last_stmt (bb
);
2506 head_code
= TREE_CODE (first
);
2507 head_name
= tree_code_name
[head_code
];
2508 head_line
= get_lineno (first
);
2511 head_name
= "no-statement";
2515 end_code
= TREE_CODE (last
);
2516 end_name
= tree_code_name
[end_code
];
2517 end_line
= get_lineno (last
);
2520 end_name
= "no-statement";
2522 fprintf (file
, "node: { title: \"%d\" label: \"#%d\\n%s (%d)\\n%s (%d)\"}\n",
2523 bb
->index
, bb
->index
, head_name
, head_line
, end_name
,
2526 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2528 if (e
->dest
== EXIT_BLOCK_PTR
)
2529 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"EXIT\"", bb
->index
);
2531 fprintf (file
, "edge: { sourcename: \"%d\" targetname: \"%d\"", bb
->index
, e
->dest
->index
);
2533 if (e
->flags
& EDGE_FAKE
)
2534 fprintf (file
, " priority: 10 linestyle: dotted");
2536 fprintf (file
, " priority: 100 linestyle: solid");
2538 fprintf (file
, " }\n");
2541 if (bb
->next_bb
!= EXIT_BLOCK_PTR
)
2545 fputs ("}\n\n", file
);
2550 /*---------------------------------------------------------------------------
2551 Miscellaneous helpers
2552 ---------------------------------------------------------------------------*/
2554 /* Return true if T represents a stmt that always transfers control. */
2557 is_ctrl_stmt (tree t
)
2559 return (TREE_CODE (t
) == COND_EXPR
2560 || TREE_CODE (t
) == SWITCH_EXPR
2561 || TREE_CODE (t
) == GOTO_EXPR
2562 || TREE_CODE (t
) == RETURN_EXPR
2563 || TREE_CODE (t
) == RESX_EXPR
);
2567 /* Return true if T is a statement that may alter the flow of control
2568 (e.g., a call to a non-returning function). */
2571 is_ctrl_altering_stmt (tree t
)
2576 call
= get_call_expr_in (t
);
2579 /* A non-pure/const CALL_EXPR alters flow control if the current
2580 function has nonlocal labels. */
2581 if (TREE_SIDE_EFFECTS (call
) && current_function_has_nonlocal_label
)
2584 /* A CALL_EXPR also alters control flow if it does not return. */
2585 if (call_expr_flags (call
) & ECF_NORETURN
)
2589 /* If a statement can throw, it alters control flow. */
2590 return tree_can_throw_internal (t
);
2594 /* Return true if T is a computed goto. */
2597 computed_goto_p (tree t
)
2599 return (TREE_CODE (t
) == GOTO_EXPR
2600 && TREE_CODE (GOTO_DESTINATION (t
)) != LABEL_DECL
);
2604 /* Checks whether EXPR is a simple local goto. */
2607 simple_goto_p (tree expr
)
2609 return (TREE_CODE (expr
) == GOTO_EXPR
2610 && TREE_CODE (GOTO_DESTINATION (expr
)) == LABEL_DECL
);
2614 /* Return true if T should start a new basic block. PREV_T is the
2615 statement preceding T. It is used when T is a label or a case label.
2616 Labels should only start a new basic block if their previous statement
2617 wasn't a label. Otherwise, sequence of labels would generate
2618 unnecessary basic blocks that only contain a single label. */
2621 stmt_starts_bb_p (tree t
, tree prev_t
)
2623 enum tree_code code
;
2628 /* LABEL_EXPRs start a new basic block only if the preceding
2629 statement wasn't a label of the same type. This prevents the
2630 creation of consecutive blocks that have nothing but a single
2632 code
= TREE_CODE (t
);
2633 if (code
== LABEL_EXPR
)
2635 /* Nonlocal and computed GOTO targets always start a new block. */
2636 if (code
== LABEL_EXPR
2637 && (DECL_NONLOCAL (LABEL_EXPR_LABEL (t
))
2638 || FORCED_LABEL (LABEL_EXPR_LABEL (t
))))
2641 if (prev_t
&& TREE_CODE (prev_t
) == code
)
2643 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (prev_t
)))
2646 cfg_stats
.num_merged_labels
++;
2657 /* Return true if T should end a basic block. */
2660 stmt_ends_bb_p (tree t
)
2662 return is_ctrl_stmt (t
) || is_ctrl_altering_stmt (t
);
2666 /* Add gotos that used to be represented implicitly in the CFG. */
2669 disband_implicit_edges (void)
2672 block_stmt_iterator last
;
2679 last
= bsi_last (bb
);
2680 stmt
= last_stmt (bb
);
2682 if (stmt
&& TREE_CODE (stmt
) == COND_EXPR
)
2684 /* Remove superfluous gotos from COND_EXPR branches. Moved
2685 from cfg_remove_useless_stmts here since it violates the
2686 invariants for tree--cfg correspondence and thus fits better
2687 here where we do it anyway. */
2688 e
= find_edge (bb
, bb
->next_bb
);
2691 if (e
->flags
& EDGE_TRUE_VALUE
)
2692 COND_EXPR_THEN (stmt
) = build_empty_stmt ();
2693 else if (e
->flags
& EDGE_FALSE_VALUE
)
2694 COND_EXPR_ELSE (stmt
) = build_empty_stmt ();
2697 e
->flags
|= EDGE_FALLTHRU
;
2703 if (stmt
&& TREE_CODE (stmt
) == RETURN_EXPR
)
2705 /* Remove the RETURN_EXPR if we may fall though to the exit
2707 gcc_assert (EDGE_COUNT (bb
->succs
) == 1);
2708 gcc_assert (EDGE_SUCC (bb
, 0)->dest
== EXIT_BLOCK_PTR
);
2710 if (bb
->next_bb
== EXIT_BLOCK_PTR
2711 && !TREE_OPERAND (stmt
, 0))
2714 EDGE_SUCC (bb
, 0)->flags
|= EDGE_FALLTHRU
;
2719 /* There can be no fallthru edge if the last statement is a control
2721 if (stmt
&& is_ctrl_stmt (stmt
))
2724 /* Find a fallthru edge and emit the goto if necessary. */
2725 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
2726 if (e
->flags
& EDGE_FALLTHRU
)
2729 if (!e
|| e
->dest
== bb
->next_bb
)
2732 gcc_assert (e
->dest
!= EXIT_BLOCK_PTR
);
2733 label
= tree_block_label (e
->dest
);
2735 stmt
= build1 (GOTO_EXPR
, void_type_node
, label
);
2736 #ifdef USE_MAPPED_LOCATION
2737 SET_EXPR_LOCATION (stmt
, e
->goto_locus
);
2739 SET_EXPR_LOCUS (stmt
, e
->goto_locus
);
2741 bsi_insert_after (&last
, stmt
, BSI_NEW_STMT
);
2742 e
->flags
&= ~EDGE_FALLTHRU
;
2746 /* Remove block annotations and other datastructures. */
2749 delete_tree_cfg_annotations (void)
2752 if (n_basic_blocks
> 0)
2753 free_blocks_annotations ();
2755 label_to_block_map
= NULL
;
2762 /* Return the first statement in basic block BB. */
2765 first_stmt (basic_block bb
)
2767 block_stmt_iterator i
= bsi_start (bb
);
2768 return !bsi_end_p (i
) ? bsi_stmt (i
) : NULL_TREE
;
2772 /* Return the last statement in basic block BB. */
2775 last_stmt (basic_block bb
)
2777 block_stmt_iterator b
= bsi_last (bb
);
2778 return !bsi_end_p (b
) ? bsi_stmt (b
) : NULL_TREE
;
2782 /* Return a pointer to the last statement in block BB. */
2785 last_stmt_ptr (basic_block bb
)
2787 block_stmt_iterator last
= bsi_last (bb
);
2788 return !bsi_end_p (last
) ? bsi_stmt_ptr (last
) : NULL
;
2792 /* Return the last statement of an otherwise empty block. Return NULL
2793 if the block is totally empty, or if it contains more than one
2797 last_and_only_stmt (basic_block bb
)
2799 block_stmt_iterator i
= bsi_last (bb
);
2805 last
= bsi_stmt (i
);
2810 /* Empty statements should no longer appear in the instruction stream.
2811 Everything that might have appeared before should be deleted by
2812 remove_useless_stmts, and the optimizers should just bsi_remove
2813 instead of smashing with build_empty_stmt.
2815 Thus the only thing that should appear here in a block containing
2816 one executable statement is a label. */
2817 prev
= bsi_stmt (i
);
2818 if (TREE_CODE (prev
) == LABEL_EXPR
)
2825 /* Mark BB as the basic block holding statement T. */
2828 set_bb_for_stmt (tree t
, basic_block bb
)
2830 if (TREE_CODE (t
) == PHI_NODE
)
2832 else if (TREE_CODE (t
) == STATEMENT_LIST
)
2834 tree_stmt_iterator i
;
2835 for (i
= tsi_start (t
); !tsi_end_p (i
); tsi_next (&i
))
2836 set_bb_for_stmt (tsi_stmt (i
), bb
);
2840 stmt_ann_t ann
= get_stmt_ann (t
);
2843 /* If the statement is a label, add the label to block-to-labels map
2844 so that we can speed up edge creation for GOTO_EXPRs. */
2845 if (TREE_CODE (t
) == LABEL_EXPR
)
2849 t
= LABEL_EXPR_LABEL (t
);
2850 uid
= LABEL_DECL_UID (t
);
2853 LABEL_DECL_UID (t
) = uid
= cfun
->last_label_uid
++;
2854 if (VARRAY_SIZE (label_to_block_map
) <= (unsigned) uid
)
2855 VARRAY_GROW (label_to_block_map
, 3 * uid
/ 2);
2858 /* We're moving an existing label. Make sure that we've
2859 removed it from the old block. */
2860 gcc_assert (!bb
|| !VARRAY_BB (label_to_block_map
, uid
));
2861 VARRAY_BB (label_to_block_map
, uid
) = bb
;
2866 /* Finds iterator for STMT. */
2868 extern block_stmt_iterator
2869 bsi_for_stmt (tree stmt
)
2871 block_stmt_iterator bsi
;
2873 for (bsi
= bsi_start (bb_for_stmt (stmt
)); !bsi_end_p (bsi
); bsi_next (&bsi
))
2874 if (bsi_stmt (bsi
) == stmt
)
2880 /* Insert statement (or statement list) T before the statement
2881 pointed-to by iterator I. M specifies how to update iterator I
2882 after insertion (see enum bsi_iterator_update). */
2885 bsi_insert_before (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2887 set_bb_for_stmt (t
, i
->bb
);
2888 tsi_link_before (&i
->tsi
, t
, m
);
2893 /* Insert statement (or statement list) T after the statement
2894 pointed-to by iterator I. M specifies how to update iterator I
2895 after insertion (see enum bsi_iterator_update). */
2898 bsi_insert_after (block_stmt_iterator
*i
, tree t
, enum bsi_iterator_update m
)
2900 set_bb_for_stmt (t
, i
->bb
);
2901 tsi_link_after (&i
->tsi
, t
, m
);
2906 /* Remove the statement pointed to by iterator I. The iterator is updated
2907 to the next statement. */
2910 bsi_remove (block_stmt_iterator
*i
)
2912 tree t
= bsi_stmt (*i
);
2913 set_bb_for_stmt (t
, NULL
);
2914 tsi_delink (&i
->tsi
);
2918 /* Move the statement at FROM so it comes right after the statement at TO. */
2921 bsi_move_after (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2923 tree stmt
= bsi_stmt (*from
);
2925 bsi_insert_after (to
, stmt
, BSI_SAME_STMT
);
2929 /* Move the statement at FROM so it comes right before the statement at TO. */
2932 bsi_move_before (block_stmt_iterator
*from
, block_stmt_iterator
*to
)
2934 tree stmt
= bsi_stmt (*from
);
2936 bsi_insert_before (to
, stmt
, BSI_SAME_STMT
);
2940 /* Move the statement at FROM to the end of basic block BB. */
2943 bsi_move_to_bb_end (block_stmt_iterator
*from
, basic_block bb
)
2945 block_stmt_iterator last
= bsi_last (bb
);
2947 /* Have to check bsi_end_p because it could be an empty block. */
2948 if (!bsi_end_p (last
) && is_ctrl_stmt (bsi_stmt (last
)))
2949 bsi_move_before (from
, &last
);
2951 bsi_move_after (from
, &last
);
2955 /* Replace the contents of the statement pointed to by iterator BSI
2956 with STMT. If PRESERVE_EH_INFO is true, the exception handling
2957 information of the original statement is preserved. */
2960 bsi_replace (const block_stmt_iterator
*bsi
, tree stmt
, bool preserve_eh_info
)
2963 tree orig_stmt
= bsi_stmt (*bsi
);
2965 SET_EXPR_LOCUS (stmt
, EXPR_LOCUS (orig_stmt
));
2966 set_bb_for_stmt (stmt
, bsi
->bb
);
2968 /* Preserve EH region information from the original statement, if
2969 requested by the caller. */
2970 if (preserve_eh_info
)
2972 eh_region
= lookup_stmt_eh_region (orig_stmt
);
2974 add_stmt_to_eh_region (stmt
, eh_region
);
2977 *bsi_stmt_ptr (*bsi
) = stmt
;
2982 /* Insert the statement pointed-to by BSI into edge E. Every attempt
2983 is made to place the statement in an existing basic block, but
2984 sometimes that isn't possible. When it isn't possible, the edge is
2985 split and the statement is added to the new block.
2987 In all cases, the returned *BSI points to the correct location. The
2988 return value is true if insertion should be done after the location,
2989 or false if it should be done before the location. If new basic block
2990 has to be created, it is stored in *NEW_BB. */
2993 tree_find_edge_insert_loc (edge e
, block_stmt_iterator
*bsi
,
2994 basic_block
*new_bb
)
2996 basic_block dest
, src
;
3002 /* If the destination has one predecessor which has no PHI nodes,
3003 insert there. Except for the exit block.
3005 The requirement for no PHI nodes could be relaxed. Basically we
3006 would have to examine the PHIs to prove that none of them used
3007 the value set by the statement we want to insert on E. That
3008 hardly seems worth the effort. */
3009 if (EDGE_COUNT (dest
->preds
) == 1
3010 && ! phi_nodes (dest
)
3011 && dest
!= EXIT_BLOCK_PTR
)
3013 *bsi
= bsi_start (dest
);
3014 if (bsi_end_p (*bsi
))
3017 /* Make sure we insert after any leading labels. */
3018 tmp
= bsi_stmt (*bsi
);
3019 while (TREE_CODE (tmp
) == LABEL_EXPR
)
3022 if (bsi_end_p (*bsi
))
3024 tmp
= bsi_stmt (*bsi
);
3027 if (bsi_end_p (*bsi
))
3029 *bsi
= bsi_last (dest
);
3036 /* If the source has one successor, the edge is not abnormal and
3037 the last statement does not end a basic block, insert there.
3038 Except for the entry block. */
3040 if ((e
->flags
& EDGE_ABNORMAL
) == 0
3041 && EDGE_COUNT (src
->succs
) == 1
3042 && src
!= ENTRY_BLOCK_PTR
)
3044 *bsi
= bsi_last (src
);
3045 if (bsi_end_p (*bsi
))
3048 tmp
= bsi_stmt (*bsi
);
3049 if (!stmt_ends_bb_p (tmp
))
3052 /* Insert code just before returning the value. We may need to decompose
3053 the return in the case it contains non-trivial operand. */
3054 if (TREE_CODE (tmp
) == RETURN_EXPR
)
3056 tree op
= TREE_OPERAND (tmp
, 0);
3057 if (!is_gimple_val (op
))
3059 gcc_assert (TREE_CODE (op
) == MODIFY_EXPR
);
3060 bsi_insert_before (bsi
, op
, BSI_NEW_STMT
);
3061 TREE_OPERAND (tmp
, 0) = TREE_OPERAND (op
, 0);
3068 /* Otherwise, create a new basic block, and split this edge. */
3069 dest
= split_edge (e
);
3072 e
= EDGE_PRED (dest
, 0);
3077 /* This routine will commit all pending edge insertions, creating any new
3078 basic blocks which are necessary. */
3081 bsi_commit_edge_inserts (void)
3087 bsi_commit_one_edge_insert (EDGE_SUCC (ENTRY_BLOCK_PTR
, 0), NULL
);
3090 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3091 bsi_commit_one_edge_insert (e
, NULL
);
3095 /* Commit insertions pending at edge E. If a new block is created, set NEW_BB
3096 to this block, otherwise set it to NULL. */
3099 bsi_commit_one_edge_insert (edge e
, basic_block
*new_bb
)
3103 if (PENDING_STMT (e
))
3105 block_stmt_iterator bsi
;
3106 tree stmt
= PENDING_STMT (e
);
3108 PENDING_STMT (e
) = NULL_TREE
;
3110 if (tree_find_edge_insert_loc (e
, &bsi
, new_bb
))
3111 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3113 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3118 /* Add STMT to the pending list of edge E. No actual insertion is
3119 made until a call to bsi_commit_edge_inserts () is made. */
3122 bsi_insert_on_edge (edge e
, tree stmt
)
3124 append_to_statement_list (stmt
, &PENDING_STMT (e
));
3127 /* Similar to bsi_insert_on_edge+bsi_commit_edge_inserts. If a new
3128 block has to be created, it is returned. */
3131 bsi_insert_on_edge_immediate (edge e
, tree stmt
)
3133 block_stmt_iterator bsi
;
3134 basic_block new_bb
= NULL
;
3136 gcc_assert (!PENDING_STMT (e
));
3138 if (tree_find_edge_insert_loc (e
, &bsi
, &new_bb
))
3139 bsi_insert_after (&bsi
, stmt
, BSI_NEW_STMT
);
3141 bsi_insert_before (&bsi
, stmt
, BSI_NEW_STMT
);
3146 /*---------------------------------------------------------------------------
3147 Tree specific functions for CFG manipulation
3148 ---------------------------------------------------------------------------*/
3150 /* Reinstall those PHI arguments queued in OLD_EDGE to NEW_EDGE. */
3153 reinstall_phi_args (edge new_edge
, edge old_edge
)
3157 if (!PENDING_STMT (old_edge
))
3160 for (var
= PENDING_STMT (old_edge
), phi
= phi_nodes (new_edge
->dest
);
3162 var
= TREE_CHAIN (var
), phi
= PHI_CHAIN (phi
))
3164 tree result
= TREE_PURPOSE (var
);
3165 tree arg
= TREE_VALUE (var
);
3167 gcc_assert (result
== PHI_RESULT (phi
));
3169 add_phi_arg (phi
, arg
, new_edge
);
3172 PENDING_STMT (old_edge
) = NULL
;
3175 /* Split a (typically critical) edge EDGE_IN. Return the new block.
3176 Abort on abnormal edges. */
3179 tree_split_edge (edge edge_in
)
3181 basic_block new_bb
, after_bb
, dest
, src
;
3184 /* Abnormal edges cannot be split. */
3185 gcc_assert (!(edge_in
->flags
& EDGE_ABNORMAL
));
3188 dest
= edge_in
->dest
;
3190 /* Place the new block in the block list. Try to keep the new block
3191 near its "logical" location. This is of most help to humans looking
3192 at debugging dumps. */
3193 if (dest
->prev_bb
&& find_edge (dest
->prev_bb
, dest
))
3194 after_bb
= edge_in
->src
;
3196 after_bb
= dest
->prev_bb
;
3198 new_bb
= create_empty_bb (after_bb
);
3199 new_bb
->frequency
= EDGE_FREQUENCY (edge_in
);
3200 new_bb
->count
= edge_in
->count
;
3201 new_edge
= make_edge (new_bb
, dest
, EDGE_FALLTHRU
);
3202 new_edge
->probability
= REG_BR_PROB_BASE
;
3203 new_edge
->count
= edge_in
->count
;
3205 e
= redirect_edge_and_branch (edge_in
, new_bb
);
3207 reinstall_phi_args (new_edge
, e
);
3213 /* Return true when BB has label LABEL in it. */
3216 has_label_p (basic_block bb
, tree label
)
3218 block_stmt_iterator bsi
;
3220 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3222 tree stmt
= bsi_stmt (bsi
);
3224 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3226 if (LABEL_EXPR_LABEL (stmt
) == label
)
3233 /* Callback for walk_tree, check that all elements with address taken are
3234 properly noticed as such. */
3237 verify_expr (tree
*tp
, int *walk_subtrees
, void *data ATTRIBUTE_UNUSED
)
3244 /* Check operand N for being valid GIMPLE and give error MSG if not.
3245 We check for constants explicitly since they are not considered
3246 gimple invariants if they overflowed. */
3247 #define CHECK_OP(N, MSG) \
3248 do { if (!CONSTANT_CLASS_P (TREE_OPERAND (t, N)) \
3249 && !is_gimple_val (TREE_OPERAND (t, N))) \
3250 { error (MSG); return TREE_OPERAND (t, N); }} while (0)
3252 switch (TREE_CODE (t
))
3255 if (SSA_NAME_IN_FREE_LIST (t
))
3257 error ("SSA name in freelist but still referenced");
3263 x
= TREE_OPERAND (t
, 0);
3264 if (TREE_CODE (x
) == BIT_FIELD_REF
3265 && is_gimple_reg (TREE_OPERAND (x
, 0)))
3267 error ("GIMPLE register modified with BIT_FIELD_REF");
3273 /* Skip any references (they will be checked when we recurse down the
3274 tree) and ensure that any variable used as a prefix is marked
3276 for (x
= TREE_OPERAND (t
, 0);
3277 handled_component_p (x
);
3278 x
= TREE_OPERAND (x
, 0))
3281 if (TREE_CODE (x
) != VAR_DECL
&& TREE_CODE (x
) != PARM_DECL
)
3283 if (!TREE_ADDRESSABLE (x
))
3285 error ("address taken, but ADDRESSABLE bit not set");
3291 x
= COND_EXPR_COND (t
);
3292 if (TREE_CODE (TREE_TYPE (x
)) != BOOLEAN_TYPE
)
3294 error ("non-boolean used in condition");
3301 case FIX_TRUNC_EXPR
:
3303 case FIX_FLOOR_EXPR
:
3304 case FIX_ROUND_EXPR
:
3309 case NON_LVALUE_EXPR
:
3310 case TRUTH_NOT_EXPR
:
3311 CHECK_OP (0, "Invalid operand to unary operator");
3318 case ARRAY_RANGE_REF
:
3320 case VIEW_CONVERT_EXPR
:
3321 /* We have a nest of references. Verify that each of the operands
3322 that determine where to reference is either a constant or a variable,
3323 verify that the base is valid, and then show we've already checked
3325 while (handled_component_p (t
))
3327 if (TREE_CODE (t
) == COMPONENT_REF
&& TREE_OPERAND (t
, 2))
3328 CHECK_OP (2, "Invalid COMPONENT_REF offset operator");
3329 else if (TREE_CODE (t
) == ARRAY_REF
3330 || TREE_CODE (t
) == ARRAY_RANGE_REF
)
3332 CHECK_OP (1, "Invalid array index.");
3333 if (TREE_OPERAND (t
, 2))
3334 CHECK_OP (2, "Invalid array lower bound.");
3335 if (TREE_OPERAND (t
, 3))
3336 CHECK_OP (3, "Invalid array stride.");
3338 else if (TREE_CODE (t
) == BIT_FIELD_REF
)
3340 CHECK_OP (1, "Invalid operand to BIT_FIELD_REF");
3341 CHECK_OP (2, "Invalid operand to BIT_FIELD_REF");
3344 t
= TREE_OPERAND (t
, 0);
3347 if (!CONSTANT_CLASS_P (t
) && !is_gimple_lvalue (t
))
3349 error ("Invalid reference prefix.");
3361 case UNORDERED_EXPR
:
3372 case TRUNC_DIV_EXPR
:
3374 case FLOOR_DIV_EXPR
:
3375 case ROUND_DIV_EXPR
:
3376 case TRUNC_MOD_EXPR
:
3378 case FLOOR_MOD_EXPR
:
3379 case ROUND_MOD_EXPR
:
3381 case EXACT_DIV_EXPR
:
3391 CHECK_OP (0, "Invalid operand to binary operator");
3392 CHECK_OP (1, "Invalid operand to binary operator");
3404 /* Verify STMT, return true if STMT is not in GIMPLE form.
3405 TODO: Implement type checking. */
3408 verify_stmt (tree stmt
, bool last_in_block
)
3412 if (!is_gimple_stmt (stmt
))
3414 error ("Is not a valid GIMPLE statement.");
3418 addr
= walk_tree (&stmt
, verify_expr
, NULL
, NULL
);
3421 debug_generic_stmt (addr
);
3425 /* If the statement is marked as part of an EH region, then it is
3426 expected that the statement could throw. Verify that when we
3427 have optimizations that simplify statements such that we prove
3428 that they cannot throw, that we update other data structures
3430 if (lookup_stmt_eh_region (stmt
) >= 0)
3432 if (!tree_could_throw_p (stmt
))
3434 error ("Statement marked for throw, but doesn%'t.");
3437 if (!last_in_block
&& tree_can_throw_internal (stmt
))
3439 error ("Statement marked for throw in middle of block.");
3447 debug_generic_stmt (stmt
);
3452 /* Return true when the T can be shared. */
3455 tree_node_can_be_shared (tree t
)
3457 if (IS_TYPE_OR_DECL_P (t
)
3458 /* We check for constants explicitly since they are not considered
3459 gimple invariants if they overflowed. */
3460 || CONSTANT_CLASS_P (t
)
3461 || is_gimple_min_invariant (t
)
3462 || TREE_CODE (t
) == SSA_NAME
3463 || t
== error_mark_node
)
3466 if (TREE_CODE (t
) == CASE_LABEL_EXPR
)
3469 while (((TREE_CODE (t
) == ARRAY_REF
|| TREE_CODE (t
) == ARRAY_RANGE_REF
)
3470 /* We check for constants explicitly since they are not considered
3471 gimple invariants if they overflowed. */
3472 && (CONSTANT_CLASS_P (TREE_OPERAND (t
, 1))
3473 || is_gimple_min_invariant (TREE_OPERAND (t
, 1))))
3474 || (TREE_CODE (t
) == COMPONENT_REF
3475 || TREE_CODE (t
) == REALPART_EXPR
3476 || TREE_CODE (t
) == IMAGPART_EXPR
))
3477 t
= TREE_OPERAND (t
, 0);
3486 /* Called via walk_trees. Verify tree sharing. */
3489 verify_node_sharing (tree
* tp
, int *walk_subtrees
, void *data
)
3491 htab_t htab
= (htab_t
) data
;
3494 if (tree_node_can_be_shared (*tp
))
3496 *walk_subtrees
= false;
3500 slot
= htab_find_slot (htab
, *tp
, INSERT
);
3509 /* Verify the GIMPLE statement chain. */
3515 block_stmt_iterator bsi
;
3520 timevar_push (TV_TREE_STMT_VERIFY
);
3521 htab
= htab_create (37, htab_hash_pointer
, htab_eq_pointer
, NULL
);
3528 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
3530 int phi_num_args
= PHI_NUM_ARGS (phi
);
3532 for (i
= 0; i
< phi_num_args
; i
++)
3534 tree t
= PHI_ARG_DEF (phi
, i
);
3537 /* Addressable variables do have SSA_NAMEs but they
3538 are not considered gimple values. */
3539 if (TREE_CODE (t
) != SSA_NAME
3540 && TREE_CODE (t
) != FUNCTION_DECL
3541 && !is_gimple_val (t
))
3543 error ("PHI def is not a GIMPLE value");
3544 debug_generic_stmt (phi
);
3545 debug_generic_stmt (t
);
3549 addr
= walk_tree (&t
, verify_expr
, NULL
, NULL
);
3552 debug_generic_stmt (addr
);
3556 addr
= walk_tree (&t
, verify_node_sharing
, htab
, NULL
);
3559 error ("Incorrect sharing of tree nodes");
3560 debug_generic_stmt (phi
);
3561 debug_generic_stmt (addr
);
3567 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
3569 tree stmt
= bsi_stmt (bsi
);
3571 err
|= verify_stmt (stmt
, bsi_end_p (bsi
));
3572 addr
= walk_tree (&stmt
, verify_node_sharing
, htab
, NULL
);
3575 error ("Incorrect sharing of tree nodes");
3576 debug_generic_stmt (stmt
);
3577 debug_generic_stmt (addr
);
3584 internal_error ("verify_stmts failed.");
3587 timevar_pop (TV_TREE_STMT_VERIFY
);
3591 /* Verifies that the flow information is OK. */
3594 tree_verify_flow_info (void)
3598 block_stmt_iterator bsi
;
3603 if (ENTRY_BLOCK_PTR
->stmt_list
)
3605 error ("ENTRY_BLOCK has a statement list associated with it\n");
3609 if (EXIT_BLOCK_PTR
->stmt_list
)
3611 error ("EXIT_BLOCK has a statement list associated with it\n");
3615 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
3616 if (e
->flags
& EDGE_FALLTHRU
)
3618 error ("Fallthru to exit from bb %d\n", e
->src
->index
);
3624 bool found_ctrl_stmt
= false;
3628 /* Skip labels on the start of basic block. */
3629 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3631 tree prev_stmt
= stmt
;
3633 stmt
= bsi_stmt (bsi
);
3635 if (TREE_CODE (stmt
) != LABEL_EXPR
)
3638 if (prev_stmt
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3640 error ("Nonlocal label %s is not first "
3641 "in a sequence of labels in bb %d",
3642 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3647 if (label_to_block (LABEL_EXPR_LABEL (stmt
)) != bb
)
3649 error ("Label %s to block does not match in bb %d\n",
3650 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3655 if (decl_function_context (LABEL_EXPR_LABEL (stmt
))
3656 != current_function_decl
)
3658 error ("Label %s has incorrect context in bb %d\n",
3659 IDENTIFIER_POINTER (DECL_NAME (LABEL_EXPR_LABEL (stmt
))),
3665 /* Verify that body of basic block BB is free of control flow. */
3666 for (; !bsi_end_p (bsi
); bsi_next (&bsi
))
3668 tree stmt
= bsi_stmt (bsi
);
3670 if (found_ctrl_stmt
)
3672 error ("Control flow in the middle of basic block %d\n",
3677 if (stmt_ends_bb_p (stmt
))
3678 found_ctrl_stmt
= true;
3680 if (TREE_CODE (stmt
) == LABEL_EXPR
)
3682 error ("Label %s in the middle of basic block %d\n",
3683 IDENTIFIER_POINTER (DECL_NAME (stmt
)),
3688 bsi
= bsi_last (bb
);
3689 if (bsi_end_p (bsi
))
3692 stmt
= bsi_stmt (bsi
);
3694 if (is_ctrl_stmt (stmt
))
3696 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3697 if (e
->flags
& EDGE_FALLTHRU
)
3699 error ("Fallthru edge after a control statement in bb %d \n",
3705 switch (TREE_CODE (stmt
))
3711 if (TREE_CODE (COND_EXPR_THEN (stmt
)) != GOTO_EXPR
3712 || TREE_CODE (COND_EXPR_ELSE (stmt
)) != GOTO_EXPR
)
3714 error ("Structured COND_EXPR at the end of bb %d\n", bb
->index
);
3718 extract_true_false_edges_from_block (bb
, &true_edge
, &false_edge
);
3720 if (!true_edge
|| !false_edge
3721 || !(true_edge
->flags
& EDGE_TRUE_VALUE
)
3722 || !(false_edge
->flags
& EDGE_FALSE_VALUE
)
3723 || (true_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3724 || (false_edge
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
))
3725 || EDGE_COUNT (bb
->succs
) >= 3)
3727 error ("Wrong outgoing edge flags at end of bb %d\n",
3732 if (!has_label_p (true_edge
->dest
,
3733 GOTO_DESTINATION (COND_EXPR_THEN (stmt
))))
3735 error ("%<then%> label does not match edge at end of bb %d\n",
3740 if (!has_label_p (false_edge
->dest
,
3741 GOTO_DESTINATION (COND_EXPR_ELSE (stmt
))))
3743 error ("%<else%> label does not match edge at end of bb %d\n",
3751 if (simple_goto_p (stmt
))
3753 error ("Explicit goto at end of bb %d\n", bb
->index
);
3758 /* FIXME. We should double check that the labels in the
3759 destination blocks have their address taken. */
3760 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3761 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_TRUE_VALUE
3762 | EDGE_FALSE_VALUE
))
3763 || !(e
->flags
& EDGE_ABNORMAL
))
3765 error ("Wrong outgoing edge flags at end of bb %d\n",
3773 if (EDGE_COUNT (bb
->succs
) != 1
3774 || (EDGE_SUCC (bb
, 0)->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3775 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3777 error ("Wrong outgoing edge flags at end of bb %d\n", bb
->index
);
3780 if (EDGE_SUCC (bb
, 0)->dest
!= EXIT_BLOCK_PTR
)
3782 error ("Return edge does not point to exit in bb %d\n",
3795 vec
= SWITCH_LABELS (stmt
);
3796 n
= TREE_VEC_LENGTH (vec
);
3798 /* Mark all the destination basic blocks. */
3799 for (i
= 0; i
< n
; ++i
)
3801 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3802 basic_block label_bb
= label_to_block (lab
);
3804 gcc_assert (!label_bb
->aux
|| label_bb
->aux
== (void *)1);
3805 label_bb
->aux
= (void *)1;
3808 /* Verify that the case labels are sorted. */
3809 prev
= TREE_VEC_ELT (vec
, 0);
3810 for (i
= 1; i
< n
- 1; ++i
)
3812 tree c
= TREE_VEC_ELT (vec
, i
);
3815 error ("Found default case not at end of case vector");
3819 if (! tree_int_cst_lt (CASE_LOW (prev
), CASE_LOW (c
)))
3821 error ("Case labels not sorted:\n ");
3822 print_generic_expr (stderr
, prev
, 0);
3823 fprintf (stderr
," is greater than ");
3824 print_generic_expr (stderr
, c
, 0);
3825 fprintf (stderr
," but comes before it.\n");
3830 if (CASE_LOW (TREE_VEC_ELT (vec
, n
- 1)))
3832 error ("No default case found at end of case vector");
3836 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3840 error ("Extra outgoing edge %d->%d\n",
3841 bb
->index
, e
->dest
->index
);
3844 e
->dest
->aux
= (void *)2;
3845 if ((e
->flags
& (EDGE_FALLTHRU
| EDGE_ABNORMAL
3846 | EDGE_TRUE_VALUE
| EDGE_FALSE_VALUE
)))
3848 error ("Wrong outgoing edge flags at end of bb %d\n",
3854 /* Check that we have all of them. */
3855 for (i
= 0; i
< n
; ++i
)
3857 tree lab
= CASE_LABEL (TREE_VEC_ELT (vec
, i
));
3858 basic_block label_bb
= label_to_block (lab
);
3860 if (label_bb
->aux
!= (void *)2)
3862 error ("Missing edge %i->%i",
3863 bb
->index
, label_bb
->index
);
3868 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3869 e
->dest
->aux
= (void *)0;
3876 if (dom_computed
[CDI_DOMINATORS
] >= DOM_NO_FAST_QUERY
)
3877 verify_dominators (CDI_DOMINATORS
);
3883 /* Updates phi nodes after creating a forwarder block joined
3884 by edge FALLTHRU. */
3887 tree_make_forwarder_block (edge fallthru
)
3891 basic_block dummy
, bb
;
3892 tree phi
, new_phi
, var
;
3894 dummy
= fallthru
->src
;
3895 bb
= fallthru
->dest
;
3897 if (EDGE_COUNT (bb
->preds
) == 1)
3900 /* If we redirected a branch we must create new phi nodes at the
3902 for (phi
= phi_nodes (dummy
); phi
; phi
= PHI_CHAIN (phi
))
3904 var
= PHI_RESULT (phi
);
3905 new_phi
= create_phi_node (var
, bb
);
3906 SSA_NAME_DEF_STMT (var
) = new_phi
;
3907 SET_PHI_RESULT (phi
, make_ssa_name (SSA_NAME_VAR (var
), phi
));
3908 add_phi_arg (new_phi
, PHI_RESULT (phi
), fallthru
);
3911 /* Ensure that the PHI node chain is in the same order. */
3912 set_phi_nodes (bb
, phi_reverse (phi_nodes (bb
)));
3914 /* Add the arguments we have stored on edges. */
3915 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3920 flush_pending_stmts (e
);
3925 /* Return true if basic block BB does nothing except pass control
3926 flow to another block and that we can safely insert a label at
3927 the start of the successor block.
3929 As a precondition, we require that BB be not equal to
3933 tree_forwarder_block_p (basic_block bb
, bool phi_wanted
)
3935 block_stmt_iterator bsi
;
3937 /* BB must have a single outgoing edge. */
3938 if (EDGE_COUNT (bb
->succs
) != 1
3939 /* If PHI_WANTED is false, BB must not have any PHI nodes.
3940 Otherwise, BB must have PHI nodes. */
3941 || (phi_nodes (bb
) != NULL_TREE
) != phi_wanted
3942 /* BB may not be a predecessor of EXIT_BLOCK_PTR. */
3943 || EDGE_SUCC (bb
, 0)->dest
== EXIT_BLOCK_PTR
3944 /* Nor should this be an infinite loop. */
3945 || EDGE_SUCC (bb
, 0)->dest
== bb
3946 /* BB may not have an abnormal outgoing edge. */
3947 || (EDGE_SUCC (bb
, 0)->flags
& EDGE_ABNORMAL
))
3951 gcc_assert (bb
!= ENTRY_BLOCK_PTR
);
3954 /* Now walk through the statements backward. We can ignore labels,
3955 anything else means this is not a forwarder block. */
3956 for (bsi
= bsi_last (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
3958 tree stmt
= bsi_stmt (bsi
);
3960 switch (TREE_CODE (stmt
))
3963 if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt
)))
3972 if (find_edge (ENTRY_BLOCK_PTR
, bb
))
3978 /* Return true if BB has at least one abnormal incoming edge. */
3981 has_abnormal_incoming_edge_p (basic_block bb
)
3986 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3987 if (e
->flags
& EDGE_ABNORMAL
)
3993 /* Removes forwarder block BB. Returns false if this failed. If a new
3994 forwarder block is created due to redirection of edges, it is
3995 stored to worklist. */
3998 remove_forwarder_block (basic_block bb
, basic_block
**worklist
)
4000 edge succ
= EDGE_SUCC (bb
, 0), e
, s
;
4001 basic_block dest
= succ
->dest
;
4005 block_stmt_iterator bsi
, bsi_to
;
4006 bool seen_abnormal_edge
= false;
4008 /* We check for infinite loops already in tree_forwarder_block_p.
4009 However it may happen that the infinite loop is created
4010 afterwards due to removal of forwarders. */
4014 /* If the destination block consists of a nonlocal label, do not merge
4016 label
= first_stmt (dest
);
4018 && TREE_CODE (label
) == LABEL_EXPR
4019 && DECL_NONLOCAL (LABEL_EXPR_LABEL (label
)))
4022 /* If there is an abnormal edge to basic block BB, but not into
4023 dest, problems might occur during removal of the phi node at out
4024 of ssa due to overlapping live ranges of registers.
4026 If there is an abnormal edge in DEST, the problems would occur
4027 anyway since cleanup_dead_labels would then merge the labels for
4028 two different eh regions, and rest of exception handling code
4031 So if there is an abnormal edge to BB, proceed only if there is
4032 no abnormal edge to DEST and there are no phi nodes in DEST. */
4033 if (has_abnormal_incoming_edge_p (bb
))
4035 seen_abnormal_edge
= true;
4037 if (has_abnormal_incoming_edge_p (dest
)
4038 || phi_nodes (dest
) != NULL_TREE
)
4042 /* If there are phi nodes in DEST, and some of the blocks that are
4043 predecessors of BB are also predecessors of DEST, check that the
4044 phi node arguments match. */
4045 if (phi_nodes (dest
))
4047 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4049 s
= find_edge (e
->src
, dest
);
4053 if (!phi_alternatives_equal (dest
, succ
, s
))
4058 /* Redirect the edges. */
4059 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4061 if (e
->flags
& EDGE_ABNORMAL
)
4063 /* If there is an abnormal edge, redirect it anyway, and
4064 move the labels to the new block to make it legal. */
4065 s
= redirect_edge_succ_nodup (e
, dest
);
4068 s
= redirect_edge_and_branch (e
, dest
);
4072 /* Create arguments for the phi nodes, since the edge was not
4074 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
4075 add_phi_arg (phi
, PHI_ARG_DEF (phi
, succ
->dest_idx
), s
);
4079 /* The source basic block might become a forwarder. We know
4080 that it was not a forwarder before, since it used to have
4081 at least two outgoing edges, so we may just add it to
4083 if (tree_forwarder_block_p (s
->src
, false))
4084 *(*worklist
)++ = s
->src
;
4088 if (seen_abnormal_edge
)
4090 /* Move the labels to the new block, so that the redirection of
4091 the abnormal edges works. */
4093 bsi_to
= bsi_start (dest
);
4094 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); )
4096 label
= bsi_stmt (bsi
);
4097 gcc_assert (TREE_CODE (label
) == LABEL_EXPR
);
4099 bsi_insert_before (&bsi_to
, label
, BSI_CONTINUE_LINKING
);
4103 /* Update the dominators. */
4104 if (dom_info_available_p (CDI_DOMINATORS
))
4106 basic_block dom
, dombb
, domdest
;
4108 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
4109 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
4112 /* Shortcut to avoid calling (relatively expensive)
4113 nearest_common_dominator unless necessary. */
4117 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
4119 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
4122 /* And kill the forwarder block. */
4123 delete_basic_block (bb
);
4128 /* Removes forwarder blocks. */
4131 cleanup_forwarder_blocks (void)
4134 bool changed
= false;
4135 basic_block
*worklist
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4136 basic_block
*current
= worklist
;
4140 if (tree_forwarder_block_p (bb
, false))
4144 while (current
!= worklist
)
4147 changed
|= remove_forwarder_block (bb
, ¤t
);
4154 /* Merge the PHI nodes at BB into those at BB's sole successor. */
4157 remove_forwarder_block_with_phi (basic_block bb
)
4159 edge succ
= EDGE_SUCC (bb
, 0);
4160 basic_block dest
= succ
->dest
;
4162 basic_block dombb
, domdest
, dom
;
4164 /* We check for infinite loops already in tree_forwarder_block_p.
4165 However it may happen that the infinite loop is created
4166 afterwards due to removal of forwarders. */
4170 /* If the destination block consists of a nonlocal label, do not
4172 label
= first_stmt (dest
);
4174 && TREE_CODE (label
) == LABEL_EXPR
4175 && DECL_NONLOCAL (LABEL_EXPR_LABEL (label
)))
4178 /* Redirect each incoming edge to BB to DEST. */
4179 while (EDGE_COUNT (bb
->preds
) > 0)
4181 edge e
= EDGE_PRED (bb
, 0), s
;
4184 s
= find_edge (e
->src
, dest
);
4187 /* We already have an edge S from E->src to DEST. If S and
4188 E->dest's sole successor edge have the same PHI arguments
4189 at DEST, redirect S to DEST. */
4190 if (phi_alternatives_equal (dest
, s
, succ
))
4192 e
= redirect_edge_and_branch (e
, dest
);
4193 PENDING_STMT (e
) = NULL_TREE
;
4197 /* PHI arguments are different. Create a forwarder block by
4198 splitting E so that we can merge PHI arguments on E to
4200 e
= EDGE_SUCC (split_edge (e
), 0);
4203 s
= redirect_edge_and_branch (e
, dest
);
4205 /* redirect_edge_and_branch must not create a new edge. */
4206 gcc_assert (s
== e
);
4208 /* Add to the PHI nodes at DEST each PHI argument removed at the
4209 destination of E. */
4210 for (phi
= phi_nodes (dest
); phi
; phi
= PHI_CHAIN (phi
))
4212 tree def
= PHI_ARG_DEF (phi
, succ
->dest_idx
);
4214 if (TREE_CODE (def
) == SSA_NAME
)
4218 /* If DEF is one of the results of PHI nodes removed during
4219 redirection, replace it with the PHI argument that used
4221 for (var
= PENDING_STMT (e
); var
; var
= TREE_CHAIN (var
))
4223 tree old_arg
= TREE_PURPOSE (var
);
4224 tree new_arg
= TREE_VALUE (var
);
4234 add_phi_arg (phi
, def
, s
);
4237 PENDING_STMT (e
) = NULL
;
4240 /* Update the dominators. */
4241 dombb
= get_immediate_dominator (CDI_DOMINATORS
, bb
);
4242 domdest
= get_immediate_dominator (CDI_DOMINATORS
, dest
);
4245 /* Shortcut to avoid calling (relatively expensive)
4246 nearest_common_dominator unless necessary. */
4250 dom
= nearest_common_dominator (CDI_DOMINATORS
, domdest
, dombb
);
4252 set_immediate_dominator (CDI_DOMINATORS
, dest
, dom
);
4254 /* Remove BB since all of BB's incoming edges have been redirected
4256 delete_basic_block (bb
);
4259 /* This pass merges PHI nodes if one feeds into another. For example,
4260 suppose we have the following:
4267 # tem_6 = PHI <tem_17(8), tem_23(7)>;
4270 # tem_3 = PHI <tem_6(9), tem_2(5)>;
4273 Then we merge the first PHI node into the second one like so:
4275 goto <bb 9> (<L10>);
4280 # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>;
4285 merge_phi_nodes (void)
4287 basic_block
*worklist
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
4288 basic_block
*current
= worklist
;
4291 calculate_dominance_info (CDI_DOMINATORS
);
4293 /* Find all PHI nodes that we may be able to merge. */
4298 /* Look for a forwarder block with PHI nodes. */
4299 if (!tree_forwarder_block_p (bb
, true))
4302 dest
= EDGE_SUCC (bb
, 0)->dest
;
4304 /* We have to feed into another basic block with PHI
4306 if (!phi_nodes (dest
)
4307 /* We don't want to deal with a basic block with
4309 || has_abnormal_incoming_edge_p (bb
))
4312 if (!dominated_by_p (CDI_DOMINATORS
, dest
, bb
))
4314 /* If BB does not dominate DEST, then the PHI nodes at
4315 DEST must be the only users of the results of the PHI
4321 /* Now let's drain WORKLIST. */
4322 while (current
!= worklist
)
4325 remove_forwarder_block_with_phi (bb
);
4332 gate_merge_phi (void)
4337 struct tree_opt_pass pass_merge_phi
= {
4338 "mergephi", /* name */
4339 gate_merge_phi
, /* gate */
4340 merge_phi_nodes
, /* execute */
4343 0, /* static_pass_number */
4344 TV_TREE_MERGE_PHI
, /* tv_id */
4345 PROP_cfg
| PROP_ssa
, /* properties_required */
4346 0, /* properties_provided */
4347 0, /* properties_destroyed */
4348 0, /* todo_flags_start */
4349 TODO_dump_func
| TODO_ggc_collect
/* todo_flags_finish */
4354 /* Return a non-special label in the head of basic block BLOCK.
4355 Create one if it doesn't exist. */
4358 tree_block_label (basic_block bb
)
4360 block_stmt_iterator i
, s
= bsi_start (bb
);
4364 for (i
= s
; !bsi_end_p (i
); first
= false, bsi_next (&i
))
4366 stmt
= bsi_stmt (i
);
4367 if (TREE_CODE (stmt
) != LABEL_EXPR
)
4369 label
= LABEL_EXPR_LABEL (stmt
);
4370 if (!DECL_NONLOCAL (label
))
4373 bsi_move_before (&i
, &s
);
4378 label
= create_artificial_label ();
4379 stmt
= build1 (LABEL_EXPR
, void_type_node
, label
);
4380 bsi_insert_before (&s
, stmt
, BSI_NEW_STMT
);
4385 /* Attempt to perform edge redirection by replacing a possibly complex
4386 jump instruction by a goto or by removing the jump completely.
4387 This can apply only if all edges now point to the same block. The
4388 parameters and return values are equivalent to
4389 redirect_edge_and_branch. */
4392 tree_try_redirect_by_replacing_jump (edge e
, basic_block target
)
4394 basic_block src
= e
->src
;
4395 block_stmt_iterator b
;
4398 /* We can replace or remove a complex jump only when we have exactly
4400 if (EDGE_COUNT (src
->succs
) != 2
4401 /* Verify that all targets will be TARGET. Specifically, the
4402 edge that is not E must also go to TARGET. */
4403 || EDGE_SUCC (src
, EDGE_SUCC (src
, 0) == e
)->dest
!= target
)
4409 stmt
= bsi_stmt (b
);
4411 if (TREE_CODE (stmt
) == COND_EXPR
4412 || TREE_CODE (stmt
) == SWITCH_EXPR
)
4415 e
= ssa_redirect_edge (e
, target
);
4416 e
->flags
= EDGE_FALLTHRU
;
4424 /* Redirect E to DEST. Return NULL on failure. Otherwise, return the
4425 edge representing the redirected branch. */
4428 tree_redirect_edge_and_branch (edge e
, basic_block dest
)
4430 basic_block bb
= e
->src
;
4431 block_stmt_iterator bsi
;
4435 if (e
->flags
& (EDGE_ABNORMAL_CALL
| EDGE_EH
))
4438 if (e
->src
!= ENTRY_BLOCK_PTR
4439 && (ret
= tree_try_redirect_by_replacing_jump (e
, dest
)))
4442 if (e
->dest
== dest
)
4445 label
= tree_block_label (dest
);
4447 bsi
= bsi_last (bb
);
4448 stmt
= bsi_end_p (bsi
) ? NULL
: bsi_stmt (bsi
);
4450 switch (stmt
? TREE_CODE (stmt
) : ERROR_MARK
)
4453 stmt
= (e
->flags
& EDGE_TRUE_VALUE
4454 ? COND_EXPR_THEN (stmt
)
4455 : COND_EXPR_ELSE (stmt
));
4456 GOTO_DESTINATION (stmt
) = label
;
4460 /* No non-abnormal edges should lead from a non-simple goto, and
4461 simple ones should be represented implicitly. */
4466 tree cases
= get_cases_for_edge (e
, stmt
);
4468 /* If we have a list of cases associated with E, then use it
4469 as it's a lot faster than walking the entire case vector. */
4472 edge e2
= find_edge (e
->src
, dest
);
4479 CASE_LABEL (cases
) = label
;
4480 cases
= TREE_CHAIN (cases
);
4483 /* If there was already an edge in the CFG, then we need
4484 to move all the cases associated with E to E2. */
4487 tree cases2
= get_cases_for_edge (e2
, stmt
);
4489 TREE_CHAIN (last
) = TREE_CHAIN (cases2
);
4490 TREE_CHAIN (cases2
) = first
;
4495 tree vec
= SWITCH_LABELS (stmt
);
4496 size_t i
, n
= TREE_VEC_LENGTH (vec
);
4498 for (i
= 0; i
< n
; i
++)
4500 tree elt
= TREE_VEC_ELT (vec
, i
);
4502 if (label_to_block (CASE_LABEL (elt
)) == e
->dest
)
4503 CASE_LABEL (elt
) = label
;
4512 e
->flags
|= EDGE_FALLTHRU
;
4516 /* Otherwise it must be a fallthru edge, and we don't need to
4517 do anything besides redirecting it. */
4518 gcc_assert (e
->flags
& EDGE_FALLTHRU
);
4522 /* Update/insert PHI nodes as necessary. */
4524 /* Now update the edges in the CFG. */
4525 e
= ssa_redirect_edge (e
, dest
);
4531 /* Simple wrapper, as we can always redirect fallthru edges. */
4534 tree_redirect_edge_and_branch_force (edge e
, basic_block dest
)
4536 e
= tree_redirect_edge_and_branch (e
, dest
);
4543 /* Splits basic block BB after statement STMT (but at least after the
4544 labels). If STMT is NULL, BB is split just after the labels. */
4547 tree_split_block (basic_block bb
, void *stmt
)
4549 block_stmt_iterator bsi
, bsi_tgt
;
4555 new_bb
= create_empty_bb (bb
);
4557 /* Redirect the outgoing edges. */
4558 new_bb
->succs
= bb
->succs
;
4560 FOR_EACH_EDGE (e
, ei
, new_bb
->succs
)
4563 if (stmt
&& TREE_CODE ((tree
) stmt
) == LABEL_EXPR
)
4566 /* Move everything from BSI to the new basic block. */
4567 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4569 act
= bsi_stmt (bsi
);
4570 if (TREE_CODE (act
) == LABEL_EXPR
)
4583 bsi_tgt
= bsi_start (new_bb
);
4584 while (!bsi_end_p (bsi
))
4586 act
= bsi_stmt (bsi
);
4588 bsi_insert_after (&bsi_tgt
, act
, BSI_NEW_STMT
);
4595 /* Moves basic block BB after block AFTER. */
4598 tree_move_block_after (basic_block bb
, basic_block after
)
4600 if (bb
->prev_bb
== after
)
4604 link_block (bb
, after
);
4610 /* Return true if basic_block can be duplicated. */
4613 tree_can_duplicate_bb_p (basic_block bb ATTRIBUTE_UNUSED
)
4618 /* Create a duplicate of the basic block BB. NOTE: This does not
4619 preserve SSA form. */
4622 tree_duplicate_bb (basic_block bb
)
4625 block_stmt_iterator bsi
, bsi_tgt
;
4627 ssa_op_iter op_iter
;
4629 new_bb
= create_empty_bb (EXIT_BLOCK_PTR
->prev_bb
);
4631 /* First copy the phi nodes. We do not copy phi node arguments here,
4632 since the edges are not ready yet. Keep the chain of phi nodes in
4633 the same order, so that we can add them later. */
4634 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4636 mark_for_rewrite (PHI_RESULT (phi
));
4637 create_phi_node (PHI_RESULT (phi
), new_bb
);
4639 set_phi_nodes (new_bb
, phi_reverse (phi_nodes (new_bb
)));
4641 bsi_tgt
= bsi_start (new_bb
);
4642 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4644 tree stmt
= bsi_stmt (bsi
);
4647 if (TREE_CODE (stmt
) == LABEL_EXPR
)
4650 /* Record the definitions. */
4651 get_stmt_operands (stmt
);
4653 FOR_EACH_SSA_TREE_OPERAND (val
, stmt
, op_iter
, SSA_OP_ALL_DEFS
)
4654 mark_for_rewrite (val
);
4656 copy
= unshare_expr (stmt
);
4658 /* Copy also the virtual operands. */
4659 get_stmt_ann (copy
);
4660 copy_virtual_operands (copy
, stmt
);
4662 bsi_insert_after (&bsi_tgt
, copy
, BSI_NEW_STMT
);
4668 /* Basic block BB_COPY was created by code duplication. Add phi node
4669 arguments for edges going out of BB_COPY. The blocks that were
4670 duplicated have rbi->duplicated set to one. */
4673 add_phi_args_after_copy_bb (basic_block bb_copy
)
4675 basic_block bb
, dest
;
4678 tree phi
, phi_copy
, phi_next
, def
;
4680 bb
= bb_copy
->rbi
->original
;
4682 FOR_EACH_EDGE (e_copy
, ei
, bb_copy
->succs
)
4684 if (!phi_nodes (e_copy
->dest
))
4687 if (e_copy
->dest
->rbi
->duplicated
)
4688 dest
= e_copy
->dest
->rbi
->original
;
4690 dest
= e_copy
->dest
;
4692 e
= find_edge (bb
, dest
);
4695 /* During loop unrolling the target of the latch edge is copied.
4696 In this case we are not looking for edge to dest, but to
4697 duplicated block whose original was dest. */
4698 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4699 if (e
->dest
->rbi
->duplicated
4700 && e
->dest
->rbi
->original
== dest
)
4703 gcc_assert (e
!= NULL
);
4706 for (phi
= phi_nodes (e
->dest
), phi_copy
= phi_nodes (e_copy
->dest
);
4708 phi
= phi_next
, phi_copy
= PHI_CHAIN (phi_copy
))
4710 phi_next
= PHI_CHAIN (phi
);
4712 gcc_assert (PHI_RESULT (phi
) == PHI_RESULT (phi_copy
));
4713 def
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4714 add_phi_arg (phi_copy
, def
, e_copy
);
4719 /* Blocks in REGION_COPY array of length N_REGION were created by
4720 duplication of basic blocks. Add phi node arguments for edges
4721 going from these blocks. */
4724 add_phi_args_after_copy (basic_block
*region_copy
, unsigned n_region
)
4728 for (i
= 0; i
< n_region
; i
++)
4729 region_copy
[i
]->rbi
->duplicated
= 1;
4731 for (i
= 0; i
< n_region
; i
++)
4732 add_phi_args_after_copy_bb (region_copy
[i
]);
4734 for (i
= 0; i
< n_region
; i
++)
4735 region_copy
[i
]->rbi
->duplicated
= 0;
4738 /* Maps the old ssa name FROM_NAME to TO_NAME. */
4740 struct ssa_name_map_entry
4746 /* Hash function for ssa_name_map_entry. */
4749 ssa_name_map_entry_hash (const void *entry
)
4751 const struct ssa_name_map_entry
*en
= entry
;
4752 return SSA_NAME_VERSION (en
->from_name
);
4755 /* Equality function for ssa_name_map_entry. */
4758 ssa_name_map_entry_eq (const void *in_table
, const void *ssa_name
)
4760 const struct ssa_name_map_entry
*en
= in_table
;
4762 return en
->from_name
== ssa_name
;
4765 /* Allocate duplicates of ssa names in list DEFINITIONS and store the mapping
4769 allocate_ssa_names (bitmap definitions
, htab_t
*map
)
4772 struct ssa_name_map_entry
*entry
;
4778 *map
= htab_create (10, ssa_name_map_entry_hash
,
4779 ssa_name_map_entry_eq
, free
);
4780 EXECUTE_IF_SET_IN_BITMAP (definitions
, 0, ver
, bi
)
4782 name
= ssa_name (ver
);
4783 slot
= htab_find_slot_with_hash (*map
, name
, SSA_NAME_VERSION (name
),
4789 entry
= xmalloc (sizeof (struct ssa_name_map_entry
));
4790 entry
->from_name
= name
;
4793 entry
->to_name
= duplicate_ssa_name (name
, SSA_NAME_DEF_STMT (name
));
4797 /* Rewrite the definition DEF in statement STMT to new ssa name as specified
4798 by the mapping MAP. */
4801 rewrite_to_new_ssa_names_def (def_operand_p def
, tree stmt
, htab_t map
)
4803 tree name
= DEF_FROM_PTR (def
);
4804 struct ssa_name_map_entry
*entry
;
4806 gcc_assert (TREE_CODE (name
) == SSA_NAME
);
4808 entry
= htab_find_with_hash (map
, name
, SSA_NAME_VERSION (name
));
4812 SET_DEF (def
, entry
->to_name
);
4813 SSA_NAME_DEF_STMT (entry
->to_name
) = stmt
;
4816 /* Rewrite the USE to new ssa name as specified by the mapping MAP. */
4819 rewrite_to_new_ssa_names_use (use_operand_p use
, htab_t map
)
4821 tree name
= USE_FROM_PTR (use
);
4822 struct ssa_name_map_entry
*entry
;
4824 if (TREE_CODE (name
) != SSA_NAME
)
4827 entry
= htab_find_with_hash (map
, name
, SSA_NAME_VERSION (name
));
4831 SET_USE (use
, entry
->to_name
);
4834 /* Rewrite the ssa names in basic block BB to new ones as specified by the
4838 rewrite_to_new_ssa_names_bb (basic_block bb
, htab_t map
)
4844 block_stmt_iterator bsi
;
4848 v_may_def_optype v_may_defs
;
4849 v_must_def_optype v_must_defs
;
4852 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4853 if (e
->flags
& EDGE_ABNORMAL
)
4856 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
4858 rewrite_to_new_ssa_names_def (PHI_RESULT_PTR (phi
), phi
, map
);
4860 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi
)) = 1;
4863 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
4865 stmt
= bsi_stmt (bsi
);
4866 get_stmt_operands (stmt
);
4867 ann
= stmt_ann (stmt
);
4869 uses
= USE_OPS (ann
);
4870 for (i
= 0; i
< NUM_USES (uses
); i
++)
4871 rewrite_to_new_ssa_names_use (USE_OP_PTR (uses
, i
), map
);
4873 defs
= DEF_OPS (ann
);
4874 for (i
= 0; i
< NUM_DEFS (defs
); i
++)
4875 rewrite_to_new_ssa_names_def (DEF_OP_PTR (defs
, i
), stmt
, map
);
4877 vuses
= VUSE_OPS (ann
);
4878 for (i
= 0; i
< NUM_VUSES (vuses
); i
++)
4879 rewrite_to_new_ssa_names_use (VUSE_OP_PTR (vuses
, i
), map
);
4881 v_may_defs
= V_MAY_DEF_OPS (ann
);
4882 for (i
= 0; i
< NUM_V_MAY_DEFS (v_may_defs
); i
++)
4884 rewrite_to_new_ssa_names_use
4885 (V_MAY_DEF_OP_PTR (v_may_defs
, i
), map
);
4886 rewrite_to_new_ssa_names_def
4887 (V_MAY_DEF_RESULT_PTR (v_may_defs
, i
), stmt
, map
);
4890 v_must_defs
= V_MUST_DEF_OPS (ann
);
4891 for (i
= 0; i
< NUM_V_MUST_DEFS (v_must_defs
); i
++)
4893 rewrite_to_new_ssa_names_def
4894 (V_MUST_DEF_RESULT_PTR (v_must_defs
, i
), stmt
, map
);
4895 rewrite_to_new_ssa_names_use
4896 (V_MUST_DEF_KILL_PTR (v_must_defs
, i
), map
);
4900 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4901 for (phi
= phi_nodes (e
->dest
); phi
; phi
= PHI_CHAIN (phi
))
4903 rewrite_to_new_ssa_names_use
4904 (PHI_ARG_DEF_PTR_FROM_EDGE (phi
, e
), map
);
4906 if (e
->flags
& EDGE_ABNORMAL
)
4908 tree op
= PHI_ARG_DEF_FROM_EDGE (phi
, e
);
4909 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
) = 1;
4914 /* Rewrite the ssa names in N_REGION blocks REGION to the new ones as specified
4915 by the mapping MAP. */
4918 rewrite_to_new_ssa_names (basic_block
*region
, unsigned n_region
, htab_t map
)
4922 for (r
= 0; r
< n_region
; r
++)
4923 rewrite_to_new_ssa_names_bb (region
[r
], map
);
4926 /* Duplicates a REGION (set of N_REGION basic blocks) with just a single
4927 important exit edge EXIT. By important we mean that no SSA name defined
4928 inside region is live over the other exit edges of the region. All entry
4929 edges to the region must go to ENTRY->dest. The edge ENTRY is redirected
4930 to the duplicate of the region. SSA form, dominance and loop information
4931 is updated. The new basic blocks are stored to REGION_COPY in the same
4932 order as they had in REGION, provided that REGION_COPY is not NULL.
4933 The function returns false if it is unable to copy the region,
4937 tree_duplicate_sese_region (edge entry
, edge exit
,
4938 basic_block
*region
, unsigned n_region
,
4939 basic_block
*region_copy
)
4941 unsigned i
, n_doms
, ver
;
4942 bool free_region_copy
= false, copying_header
= false;
4943 struct loop
*loop
= entry
->dest
->loop_father
;
4948 htab_t ssa_name_map
= NULL
;
4952 if (!can_copy_bbs_p (region
, n_region
))
4955 /* Some sanity checking. Note that we do not check for all possible
4956 missuses of the functions. I.e. if you ask to copy something weird,
4957 it will work, but the state of structures probably will not be
4960 for (i
= 0; i
< n_region
; i
++)
4962 /* We do not handle subloops, i.e. all the blocks must belong to the
4964 if (region
[i
]->loop_father
!= loop
)
4967 if (region
[i
] != entry
->dest
4968 && region
[i
] == loop
->header
)
4974 /* In case the function is used for loop header copying (which is the primary
4975 use), ensure that EXIT and its copy will be new latch and entry edges. */
4976 if (loop
->header
== entry
->dest
)
4978 copying_header
= true;
4979 loop
->copy
= loop
->outer
;
4981 if (!dominated_by_p (CDI_DOMINATORS
, loop
->latch
, exit
->src
))
4984 for (i
= 0; i
< n_region
; i
++)
4985 if (region
[i
] != exit
->src
4986 && dominated_by_p (CDI_DOMINATORS
, region
[i
], exit
->src
))
4992 region_copy
= xmalloc (sizeof (basic_block
) * n_region
);
4993 free_region_copy
= true;
4996 gcc_assert (!any_marked_for_rewrite_p ());
4998 /* Record blocks outside the region that are duplicated by something
5000 doms
= xmalloc (sizeof (basic_block
) * n_basic_blocks
);
5001 n_doms
= get_dominated_by_region (CDI_DOMINATORS
, region
, n_region
, doms
);
5003 copy_bbs (region
, n_region
, region_copy
, &exit
, 1, &exit_copy
, loop
);
5004 definitions
= marked_ssa_names ();
5008 loop
->header
= exit
->dest
;
5009 loop
->latch
= exit
->src
;
5012 /* Redirect the entry and add the phi node arguments. */
5013 redirected
= redirect_edge_and_branch (entry
, entry
->dest
->rbi
->copy
);
5014 gcc_assert (redirected
!= NULL
);
5015 flush_pending_stmts (entry
);
5017 /* Concerning updating of dominators: We must recount dominators
5018 for entry block and its copy. Anything that is outside of the region, but
5019 was dominated by something inside needs recounting as well. */
5020 set_immediate_dominator (CDI_DOMINATORS
, entry
->dest
, entry
->src
);
5021 doms
[n_doms
++] = entry
->dest
->rbi
->original
;
5022 iterate_fix_dominators (CDI_DOMINATORS
, doms
, n_doms
);
5025 /* Add the other phi node arguments. */
5026 add_phi_args_after_copy (region_copy
, n_region
);
5028 /* Add phi nodes for definitions at exit. TODO -- once we have immediate
5029 uses, it should be possible to emit phi nodes just for definitions that
5030 are used outside region. */
5031 EXECUTE_IF_SET_IN_BITMAP (definitions
, 0, ver
, bi
)
5033 tree name
= ssa_name (ver
);
5035 phi
= create_phi_node (name
, exit
->dest
);
5036 add_phi_arg (phi
, name
, exit
);
5037 add_phi_arg (phi
, name
, exit_copy
);
5039 SSA_NAME_DEF_STMT (name
) = phi
;
5042 /* And create new definitions inside region and its copy. TODO -- once we
5043 have immediate uses, it might be better to leave definitions in region
5044 unchanged, create new ssa names for phi nodes on exit, and rewrite
5045 the uses, to avoid changing the copied region. */
5046 allocate_ssa_names (definitions
, &ssa_name_map
);
5047 rewrite_to_new_ssa_names (region
, n_region
, ssa_name_map
);
5048 allocate_ssa_names (definitions
, &ssa_name_map
);
5049 rewrite_to_new_ssa_names (region_copy
, n_region
, ssa_name_map
);
5050 htab_delete (ssa_name_map
);
5052 if (free_region_copy
)
5055 unmark_all_for_rewrite ();
5056 BITMAP_XFREE (definitions
);
5061 /* Dump FUNCTION_DECL FN to file FILE using FLAGS (see TDF_* in tree.h) */
5064 dump_function_to_file (tree fn
, FILE *file
, int flags
)
5066 tree arg
, vars
, var
;
5067 bool ignore_topmost_bind
= false, any_var
= false;
5071 fprintf (file
, "%s (", lang_hooks
.decl_printable_name (fn
, 2));
5073 arg
= DECL_ARGUMENTS (fn
);
5076 print_generic_expr (file
, arg
, dump_flags
);
5077 if (TREE_CHAIN (arg
))
5078 fprintf (file
, ", ");
5079 arg
= TREE_CHAIN (arg
);
5081 fprintf (file
, ")\n");
5083 if (flags
& TDF_RAW
)
5085 dump_node (fn
, TDF_SLIM
| flags
, file
);
5089 /* When GIMPLE is lowered, the variables are no longer available in
5090 BIND_EXPRs, so display them separately. */
5091 if (cfun
&& cfun
->unexpanded_var_list
)
5093 ignore_topmost_bind
= true;
5095 fprintf (file
, "{\n");
5096 for (vars
= cfun
->unexpanded_var_list
; vars
; vars
= TREE_CHAIN (vars
))
5098 var
= TREE_VALUE (vars
);
5100 print_generic_decl (file
, var
, flags
);
5101 fprintf (file
, "\n");
5107 if (basic_block_info
)
5109 /* Make a CFG based dump. */
5110 check_bb_profile (ENTRY_BLOCK_PTR
, file
);
5111 if (!ignore_topmost_bind
)
5112 fprintf (file
, "{\n");
5114 if (any_var
&& n_basic_blocks
)
5115 fprintf (file
, "\n");
5118 dump_generic_bb (file
, bb
, 2, flags
);
5120 fprintf (file
, "}\n");
5121 check_bb_profile (EXIT_BLOCK_PTR
, file
);
5127 /* Make a tree based dump. */
5128 chain
= DECL_SAVED_TREE (fn
);
5130 if (TREE_CODE (chain
) == BIND_EXPR
)
5132 if (ignore_topmost_bind
)
5134 chain
= BIND_EXPR_BODY (chain
);
5142 if (!ignore_topmost_bind
)
5143 fprintf (file
, "{\n");
5148 fprintf (file
, "\n");
5150 print_generic_stmt_indented (file
, chain
, flags
, indent
);
5151 if (ignore_topmost_bind
)
5152 fprintf (file
, "}\n");
5155 fprintf (file
, "\n\n");
5159 /* Pretty print of the loops intermediate representation. */
5160 static void print_loop (FILE *, struct loop
*, int);
5161 static void print_pred_bbs (FILE *, basic_block bb
);
5162 static void print_succ_bbs (FILE *, basic_block bb
);
5165 /* Print the predecessors indexes of edge E on FILE. */
5168 print_pred_bbs (FILE *file
, basic_block bb
)
5173 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5174 fprintf (file
, "bb_%d", e
->src
->index
);
5178 /* Print the successors indexes of edge E on FILE. */
5181 print_succ_bbs (FILE *file
, basic_block bb
)
5186 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5187 fprintf (file
, "bb_%d", e
->src
->index
);
5191 /* Pretty print LOOP on FILE, indented INDENT spaces. */
5194 print_loop (FILE *file
, struct loop
*loop
, int indent
)
5202 s_indent
= (char *) alloca ((size_t) indent
+ 1);
5203 memset ((void *) s_indent
, ' ', (size_t) indent
);
5204 s_indent
[indent
] = '\0';
5206 /* Print the loop's header. */
5207 fprintf (file
, "%sloop_%d\n", s_indent
, loop
->num
);
5209 /* Print the loop's body. */
5210 fprintf (file
, "%s{\n", s_indent
);
5212 if (bb
->loop_father
== loop
)
5214 /* Print the basic_block's header. */
5215 fprintf (file
, "%s bb_%d (preds = {", s_indent
, bb
->index
);
5216 print_pred_bbs (file
, bb
);
5217 fprintf (file
, "}, succs = {");
5218 print_succ_bbs (file
, bb
);
5219 fprintf (file
, "})\n");
5221 /* Print the basic_block's body. */
5222 fprintf (file
, "%s {\n", s_indent
);
5223 tree_dump_bb (bb
, file
, indent
+ 4);
5224 fprintf (file
, "%s }\n", s_indent
);
5227 print_loop (file
, loop
->inner
, indent
+ 2);
5228 fprintf (file
, "%s}\n", s_indent
);
5229 print_loop (file
, loop
->next
, indent
);
5233 /* Follow a CFG edge from the entry point of the program, and on entry
5234 of a loop, pretty print the loop structure on FILE. */
5237 print_loop_ir (FILE *file
)
5241 bb
= BASIC_BLOCK (0);
5242 if (bb
&& bb
->loop_father
)
5243 print_loop (file
, bb
->loop_father
, 0);
5247 /* Debugging loops structure at tree level. */
5250 debug_loop_ir (void)
5252 print_loop_ir (stderr
);
5256 /* Return true if BB ends with a call, possibly followed by some
5257 instructions that must stay with the call. Return false,
5261 tree_block_ends_with_call_p (basic_block bb
)
5263 block_stmt_iterator bsi
= bsi_last (bb
);
5264 return get_call_expr_in (bsi_stmt (bsi
)) != NULL
;
5268 /* Return true if BB ends with a conditional branch. Return false,
5272 tree_block_ends_with_condjump_p (basic_block bb
)
5274 tree stmt
= tsi_stmt (bsi_last (bb
).tsi
);
5275 return (TREE_CODE (stmt
) == COND_EXPR
);
5279 /* Return true if we need to add fake edge to exit at statement T.
5280 Helper function for tree_flow_call_edges_add. */
5283 need_fake_edge_p (tree t
)
5287 /* NORETURN and LONGJMP calls already have an edge to exit.
5288 CONST, PURE and ALWAYS_RETURN calls do not need one.
5289 We don't currently check for CONST and PURE here, although
5290 it would be a good idea, because those attributes are
5291 figured out from the RTL in mark_constant_function, and
5292 the counter incrementation code from -fprofile-arcs
5293 leads to different results from -fbranch-probabilities. */
5294 call
= get_call_expr_in (t
);
5296 && !(call_expr_flags (call
) & (ECF_NORETURN
| ECF_ALWAYS_RETURN
)))
5299 if (TREE_CODE (t
) == ASM_EXPR
5300 && (ASM_VOLATILE_P (t
) || ASM_INPUT_P (t
)))
5307 /* Add fake edges to the function exit for any non constant and non
5308 noreturn calls, volatile inline assembly in the bitmap of blocks
5309 specified by BLOCKS or to the whole CFG if BLOCKS is zero. Return
5310 the number of blocks that were split.
5312 The goal is to expose cases in which entering a basic block does
5313 not imply that all subsequent instructions must be executed. */
5316 tree_flow_call_edges_add (sbitmap blocks
)
5319 int blocks_split
= 0;
5320 int last_bb
= last_basic_block
;
5321 bool check_last_block
= false;
5323 if (n_basic_blocks
== 0)
5327 check_last_block
= true;
5329 check_last_block
= TEST_BIT (blocks
, EXIT_BLOCK_PTR
->prev_bb
->index
);
5331 /* In the last basic block, before epilogue generation, there will be
5332 a fallthru edge to EXIT. Special care is required if the last insn
5333 of the last basic block is a call because make_edge folds duplicate
5334 edges, which would result in the fallthru edge also being marked
5335 fake, which would result in the fallthru edge being removed by
5336 remove_fake_edges, which would result in an invalid CFG.
5338 Moreover, we can't elide the outgoing fake edge, since the block
5339 profiler needs to take this into account in order to solve the minimal
5340 spanning tree in the case that the call doesn't return.
5342 Handle this by adding a dummy instruction in a new last basic block. */
5343 if (check_last_block
)
5345 basic_block bb
= EXIT_BLOCK_PTR
->prev_bb
;
5346 block_stmt_iterator bsi
= bsi_last (bb
);
5348 if (!bsi_end_p (bsi
))
5351 if (need_fake_edge_p (t
))
5355 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5358 bsi_insert_on_edge (e
, build_empty_stmt ());
5359 bsi_commit_edge_inserts ();
5364 /* Now add fake edges to the function exit for any non constant
5365 calls since there is no way that we can determine if they will
5367 for (i
= 0; i
< last_bb
; i
++)
5369 basic_block bb
= BASIC_BLOCK (i
);
5370 block_stmt_iterator bsi
;
5371 tree stmt
, last_stmt
;
5376 if (blocks
&& !TEST_BIT (blocks
, i
))
5379 bsi
= bsi_last (bb
);
5380 if (!bsi_end_p (bsi
))
5382 last_stmt
= bsi_stmt (bsi
);
5385 stmt
= bsi_stmt (bsi
);
5386 if (need_fake_edge_p (stmt
))
5389 /* The handling above of the final block before the
5390 epilogue should be enough to verify that there is
5391 no edge to the exit block in CFG already.
5392 Calling make_edge in such case would cause us to
5393 mark that edge as fake and remove it later. */
5394 #ifdef ENABLE_CHECKING
5395 if (stmt
== last_stmt
)
5397 e
= find_edge (bb
, EXIT_BLOCK_PTR
);
5398 gcc_assert (e
== NULL
);
5402 /* Note that the following may create a new basic block
5403 and renumber the existing basic blocks. */
5404 if (stmt
!= last_stmt
)
5406 e
= split_block (bb
, stmt
);
5410 make_edge (bb
, EXIT_BLOCK_PTR
, EDGE_FAKE
);
5414 while (!bsi_end_p (bsi
));
5419 verify_flow_info ();
5421 return blocks_split
;
5425 tree_purge_dead_eh_edges (basic_block bb
)
5427 bool changed
= false;
5430 tree stmt
= last_stmt (bb
);
5432 if (stmt
&& tree_can_throw_internal (stmt
))
5435 for (ei
= ei_start (bb
->succs
); (e
= ei_safe_edge (ei
)); )
5437 if (e
->flags
& EDGE_EH
)
5446 /* Removal of dead EH edges might change dominators of not
5447 just immediate successors. E.g. when bb1 is changed so that
5448 it no longer can throw and bb1->bb3 and bb1->bb4 are dead
5449 eh edges purged by this function in:
5461 idom(bb5) must be recomputed. For now just free the dominance
5464 free_dominance_info (CDI_DOMINATORS
);
5470 tree_purge_all_dead_eh_edges (bitmap blocks
)
5472 bool changed
= false;
5476 EXECUTE_IF_SET_IN_BITMAP (blocks
, 0, i
, bi
)
5478 changed
|= tree_purge_dead_eh_edges (BASIC_BLOCK (i
));
5484 /* This function is called whenever a new edge is created or
5488 tree_execute_on_growing_pred (edge e
)
5490 basic_block bb
= e
->dest
;
5493 reserve_phi_args_for_new_edge (bb
);
5496 /* This function is called immediately before edge E is removed from
5497 the edge vector E->dest->preds. */
5500 tree_execute_on_shrinking_pred (edge e
)
5502 if (phi_nodes (e
->dest
))
5503 remove_phi_args (e
);
5506 struct cfg_hooks tree_cfg_hooks
= {
5508 tree_verify_flow_info
,
5509 tree_dump_bb
, /* dump_bb */
5510 create_bb
, /* create_basic_block */
5511 tree_redirect_edge_and_branch
,/* redirect_edge_and_branch */
5512 tree_redirect_edge_and_branch_force
,/* redirect_edge_and_branch_force */
5513 remove_bb
, /* delete_basic_block */
5514 tree_split_block
, /* split_block */
5515 tree_move_block_after
, /* move_block_after */
5516 tree_can_merge_blocks_p
, /* can_merge_blocks_p */
5517 tree_merge_blocks
, /* merge_blocks */
5518 tree_predict_edge
, /* predict_edge */
5519 tree_predicted_by_p
, /* predicted_by_p */
5520 tree_can_duplicate_bb_p
, /* can_duplicate_block_p */
5521 tree_duplicate_bb
, /* duplicate_block */
5522 tree_split_edge
, /* split_edge */
5523 tree_make_forwarder_block
, /* make_forward_block */
5524 NULL
, /* tidy_fallthru_edge */
5525 tree_block_ends_with_call_p
, /* block_ends_with_call_p */
5526 tree_block_ends_with_condjump_p
, /* block_ends_with_condjump_p */
5527 tree_flow_call_edges_add
, /* flow_call_edges_add */
5528 tree_execute_on_growing_pred
, /* execute_on_growing_pred */
5529 tree_execute_on_shrinking_pred
, /* execute_on_shrinking_pred */
5533 /* Split all critical edges. */
5536 split_critical_edges (void)
5542 /* split_edge can redirect edges out of SWITCH_EXPRs, which can get
5543 expensive. So we want to enable recording of edge to CASE_LABEL_EXPR
5544 mappings around the calls to split_edge. */
5545 start_recording_case_labels ();
5548 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5549 if (EDGE_CRITICAL_P (e
) && !(e
->flags
& EDGE_ABNORMAL
))
5554 end_recording_case_labels ();
5557 struct tree_opt_pass pass_split_crit_edges
=
5559 "crited", /* name */
5561 split_critical_edges
, /* execute */
5564 0, /* static_pass_number */
5565 TV_TREE_SPLIT_EDGES
, /* tv_id */
5566 PROP_cfg
, /* properties required */
5567 PROP_no_crit_edges
, /* properties_provided */
5568 0, /* properties_destroyed */
5569 0, /* todo_flags_start */
5570 TODO_dump_func
, /* todo_flags_finish */
5575 /* Return EXP if it is a valid GIMPLE rvalue, else gimplify it into
5576 a temporary, make sure and register it to be renamed if necessary,
5577 and finally return the temporary. Put the statements to compute
5578 EXP before the current statement in BSI. */
5581 gimplify_val (block_stmt_iterator
*bsi
, tree type
, tree exp
)
5583 tree t
, new_stmt
, orig_stmt
;
5585 if (is_gimple_val (exp
))
5588 t
= make_rename_temp (type
, NULL
);
5589 new_stmt
= build (MODIFY_EXPR
, type
, t
, exp
);
5591 orig_stmt
= bsi_stmt (*bsi
);
5592 SET_EXPR_LOCUS (new_stmt
, EXPR_LOCUS (orig_stmt
));
5593 TREE_BLOCK (new_stmt
) = TREE_BLOCK (orig_stmt
);
5595 bsi_insert_before (bsi
, new_stmt
, BSI_SAME_STMT
);
5600 /* Build a ternary operation and gimplify it. Emit code before BSI.
5601 Return the gimple_val holding the result. */
5604 gimplify_build3 (block_stmt_iterator
*bsi
, enum tree_code code
,
5605 tree type
, tree a
, tree b
, tree c
)
5609 ret
= fold (build3 (code
, type
, a
, b
, c
));
5612 return gimplify_val (bsi
, type
, ret
);
5615 /* Build a binary operation and gimplify it. Emit code before BSI.
5616 Return the gimple_val holding the result. */
5619 gimplify_build2 (block_stmt_iterator
*bsi
, enum tree_code code
,
5620 tree type
, tree a
, tree b
)
5624 ret
= fold (build2 (code
, type
, a
, b
));
5627 return gimplify_val (bsi
, type
, ret
);
5630 /* Build a unary operation and gimplify it. Emit code before BSI.
5631 Return the gimple_val holding the result. */
5634 gimplify_build1 (block_stmt_iterator
*bsi
, enum tree_code code
, tree type
,
5639 ret
= fold (build1 (code
, type
, a
));
5642 return gimplify_val (bsi
, type
, ret
);
5647 /* Emit return warnings. */
5650 execute_warn_function_return (void)
5652 #ifdef USE_MAPPED_LOCATION
5653 source_location location
;
5661 if (warn_missing_noreturn
5662 && !TREE_THIS_VOLATILE (cfun
->decl
)
5663 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) == 0
5664 && !lang_hooks
.function
.missing_noreturn_ok_p (cfun
->decl
))
5665 warning ("%Jfunction might be possible candidate for "
5666 "attribute %<noreturn%>",
5669 /* If we have a path to EXIT, then we do return. */
5670 if (TREE_THIS_VOLATILE (cfun
->decl
)
5671 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0)
5673 #ifdef USE_MAPPED_LOCATION
5674 location
= UNKNOWN_LOCATION
;
5678 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5680 last
= last_stmt (e
->src
);
5681 if (TREE_CODE (last
) == RETURN_EXPR
5682 #ifdef USE_MAPPED_LOCATION
5683 && (location
= EXPR_LOCATION (last
)) != UNKNOWN_LOCATION
)
5685 && (locus
= EXPR_LOCUS (last
)) != NULL
)
5689 #ifdef USE_MAPPED_LOCATION
5690 if (location
== UNKNOWN_LOCATION
)
5691 location
= cfun
->function_end_locus
;
5692 warning ("%H%<noreturn%> function does return", &location
);
5695 locus
= &cfun
->function_end_locus
;
5696 warning ("%H%<noreturn%> function does return", locus
);
5700 /* If we see "return;" in some basic block, then we do reach the end
5701 without returning a value. */
5702 else if (warn_return_type
5703 && !TREE_NO_WARNING (cfun
->decl
)
5704 && EDGE_COUNT (EXIT_BLOCK_PTR
->preds
) > 0
5705 && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (cfun
->decl
))))
5707 FOR_EACH_EDGE (e
, ei
, EXIT_BLOCK_PTR
->preds
)
5709 tree last
= last_stmt (e
->src
);
5710 if (TREE_CODE (last
) == RETURN_EXPR
5711 && TREE_OPERAND (last
, 0) == NULL
)
5713 #ifdef USE_MAPPED_LOCATION
5714 location
= EXPR_LOCATION (last
);
5715 if (location
== UNKNOWN_LOCATION
)
5716 location
= cfun
->function_end_locus
;
5717 warning ("%Hcontrol reaches end of non-void function", &location
);
5719 locus
= EXPR_LOCUS (last
);
5721 locus
= &cfun
->function_end_locus
;
5722 warning ("%Hcontrol reaches end of non-void function", locus
);
5724 TREE_NO_WARNING (cfun
->decl
) = 1;
5732 /* Given a basic block B which ends with a conditional and has
5733 precisely two successors, determine which of the edges is taken if
5734 the conditional is true and which is taken if the conditional is
5735 false. Set TRUE_EDGE and FALSE_EDGE appropriately. */
5738 extract_true_false_edges_from_block (basic_block b
,
5742 edge e
= EDGE_SUCC (b
, 0);
5744 if (e
->flags
& EDGE_TRUE_VALUE
)
5747 *false_edge
= EDGE_SUCC (b
, 1);
5752 *true_edge
= EDGE_SUCC (b
, 1);
5756 struct tree_opt_pass pass_warn_function_return
=
5760 execute_warn_function_return
, /* execute */
5763 0, /* static_pass_number */
5765 PROP_cfg
, /* properties_required */
5766 0, /* properties_provided */
5767 0, /* properties_destroyed */
5768 0, /* todo_flags_start */
5769 0, /* todo_flags_finish */
5773 #include "gt-tree-cfg.h"