1 /* Liveness for SSA trees.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation,
4 Contributed by Andrew MacLeod <amacleod@redhat.com>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
27 #include "diagnostic.h"
29 #include "tree-flow.h"
30 #include "tree-dump.h"
31 #include "tree-ssa-live.h"
36 #ifdef ENABLE_CHECKING
37 static void verify_live_on_entry (tree_live_info_p
);
41 /* VARMAP maintains a mapping from SSA version number to real variables.
43 All SSA_NAMES are divided into partitions. Initially each ssa_name is the
44 only member of it's own partition. Coalescing will attempt to group any
45 ssa_names which occur in a copy or in a PHI node into the same partition.
47 At the end of out-of-ssa, each partition becomes a "real" variable and is
48 rewritten as a compiler variable.
50 The var_map data structure is used to manage these partitions. It allows
51 partitions to be combined, and determines which partition belongs to what
52 ssa_name or variable, and vice versa. */
55 /* This routine will initialize the basevar fields of MAP. */
58 var_map_base_init (var_map map
)
65 num_part
= num_var_partitions (map
);
67 /* If a base table already exists, clear it, otherwise create it. */
68 if (map
->partition_to_base_index
!= NULL
)
70 free (map
->partition_to_base_index
);
71 VEC_truncate (tree
, map
->basevars
, 0);
74 map
->basevars
= VEC_alloc (tree
, heap
, MAX (40, (num_part
/ 10)));
76 map
->partition_to_base_index
= (int *) xmalloc (sizeof (int) * num_part
);
78 /* Build the base variable list, and point partitions at their bases. */
79 for (x
= 0; x
< num_part
; x
++)
81 var
= partition_to_var (map
, x
);
82 if (TREE_CODE (var
) == SSA_NAME
)
83 var
= SSA_NAME_VAR (var
);
85 /* If base variable hasn't been seen, set it up. */
86 if (!ann
->base_var_processed
)
88 ann
->base_var_processed
= 1;
89 VAR_ANN_BASE_INDEX (ann
) = num
++;
90 VEC_safe_push (tree
, heap
, map
->basevars
, var
);
92 map
->partition_to_base_index
[x
] = VAR_ANN_BASE_INDEX (ann
);
95 map
->num_basevars
= num
;
97 /* Now clear the processed bit. */
98 for (x
= 0; x
< num
; x
++)
100 var
= VEC_index (tree
, map
->basevars
, x
);
101 var_ann (var
)->base_var_processed
= 0;
104 #ifdef ENABLE_CHECKING
105 for (x
= 0; x
< num_part
; x
++)
108 var
= SSA_NAME_VAR (partition_to_var (map
, x
));
109 var2
= VEC_index (tree
, map
->basevars
, basevar_index (map
, x
));
110 gcc_assert (var
== var2
);
116 /* Remove the base table in MAP. */
119 var_map_base_fini (var_map map
)
121 /* Free the basevar info if it is present. */
122 if (map
->partition_to_base_index
!= NULL
)
124 VEC_free (tree
, heap
, map
->basevars
);
125 free (map
->partition_to_base_index
);
126 map
->partition_to_base_index
= NULL
;
127 map
->num_basevars
= 0;
130 /* Create a variable partition map of SIZE, initialize and return it. */
133 init_var_map (int size
)
137 map
= (var_map
) xmalloc (sizeof (struct _var_map
));
138 map
->var_partition
= partition_new (size
);
139 map
->partition_to_var
140 = (tree
*)xmalloc (size
* sizeof (tree
));
141 memset (map
->partition_to_var
, 0, size
* sizeof (tree
));
143 map
->partition_to_view
= NULL
;
144 map
->view_to_partition
= NULL
;
145 map
->num_partitions
= size
;
146 map
->partition_size
= size
;
147 map
->num_basevars
= 0;
148 map
->partition_to_base_index
= NULL
;
149 map
->basevars
= NULL
;
154 /* Free memory associated with MAP. */
157 delete_var_map (var_map map
)
159 var_map_base_fini (map
);
160 free (map
->partition_to_var
);
161 partition_delete (map
->var_partition
);
162 if (map
->partition_to_view
)
163 free (map
->partition_to_view
);
164 if (map
->view_to_partition
)
165 free (map
->view_to_partition
);
170 /* This function will combine the partitions in MAP for VAR1 and VAR2. It
171 Returns the partition which represents the new partition. If the two
172 partitions cannot be combined, NO_PARTITION is returned. */
175 var_union (var_map map
, tree var1
, tree var2
)
178 tree root_var
= NULL_TREE
;
179 tree other_var
= NULL_TREE
;
181 /* This is independent of partition_to_view. If partition_to_view is
182 on, then whichever one of these partitions is absorbed will never have a
183 dereference into the partition_to_view array any more. */
185 if (TREE_CODE (var1
) == SSA_NAME
)
186 p1
= partition_find (map
->var_partition
, SSA_NAME_VERSION (var1
));
189 p1
= var_to_partition (map
, var1
);
190 if (map
->view_to_partition
)
191 p1
= map
->view_to_partition
[p1
];
195 if (TREE_CODE (var2
) == SSA_NAME
)
196 p2
= partition_find (map
->var_partition
, SSA_NAME_VERSION (var2
));
199 p2
= var_to_partition (map
, var2
);
200 if (map
->view_to_partition
)
201 p2
= map
->view_to_partition
[p2
];
203 /* If there is no root_var set, or it's not a user variable, set the
204 root_var to this one. */
205 if (!root_var
|| (DECL_P (root_var
) && DECL_IGNORED_P (root_var
)))
207 other_var
= root_var
;
214 gcc_assert (p1
!= NO_PARTITION
);
215 gcc_assert (p2
!= NO_PARTITION
);
220 p3
= partition_union (map
->var_partition
, p1
, p2
);
222 if (map
->partition_to_view
)
223 p3
= map
->partition_to_view
[p3
];
226 change_partition_var (map
, root_var
, p3
);
228 change_partition_var (map
, other_var
, p3
);
234 /* Compress the partition numbers in MAP such that they fall in the range
235 0..(num_partitions-1) instead of wherever they turned out during
236 the partitioning exercise. This removes any references to unused
237 partitions, thereby allowing bitmaps and other vectors to be much
240 This is implemented such that compaction doesn't affect partitioning.
241 Ie., once partitions are created and possibly merged, running one
242 or more different kind of compaction will not affect the partitions
243 themselves. Their index might change, but all the same variables will
244 still be members of the same partition group. This allows work on reduced
245 sets, and no loss of information when a larger set is later desired.
247 In particular, coalescing can work on partitions which have 2 or more
248 definitions, and then 'recompact' later to include all the single
249 definitions for assignment to program variables. */
252 /* Set MAP back to the initial state of having no partition view. Return a
253 bitmap which has a bit set for each partition number which is in use in the
257 partition_view_init (var_map map
)
263 used
= BITMAP_ALLOC (NULL
);
265 /* Already in a view? Abandon the old one. */
266 if (map
->partition_to_view
)
268 free (map
->partition_to_view
);
269 map
->partition_to_view
= NULL
;
271 if (map
->view_to_partition
)
273 free (map
->view_to_partition
);
274 map
->view_to_partition
= NULL
;
277 /* Find out which partitions are actually referenced. */
278 for (x
= 0; x
< map
->partition_size
; x
++)
280 tmp
= partition_find (map
->var_partition
, x
);
281 if (map
->partition_to_var
[tmp
] != NULL_TREE
&& !bitmap_bit_p (used
, tmp
))
282 bitmap_set_bit (used
, tmp
);
285 map
->num_partitions
= map
->partition_size
;
290 /* This routine will finalize the view data for MAP based on the partitions
291 set in SELECTED. This is either the same bitmap returned from
292 partition_view_init, or a trimmed down version if some of those partitions
293 were not desired in this view. SELECTED is freed before returning. */
296 partition_view_fini (var_map map
, bitmap selected
)
299 unsigned count
, i
, x
, limit
;
302 gcc_assert (selected
);
304 count
= bitmap_count_bits (selected
);
305 limit
= map
->partition_size
;
307 /* If its a one-to-one ratio, we don't need any view compaction. */
310 map
->partition_to_view
= (int *)xmalloc (limit
* sizeof (int));
311 memset (map
->partition_to_view
, 0xff, (limit
* sizeof (int)));
312 map
->view_to_partition
= (int *)xmalloc (count
* sizeof (int));
315 /* Give each selected partition an index. */
316 EXECUTE_IF_SET_IN_BITMAP (selected
, 0, x
, bi
)
318 map
->partition_to_view
[x
] = i
;
319 map
->view_to_partition
[i
] = x
;
320 var
= map
->partition_to_var
[x
];
321 /* If any one of the members of a partition is not an SSA_NAME, make
322 sure it is the representative. */
323 if (TREE_CODE (var
) != SSA_NAME
)
324 change_partition_var (map
, var
, i
);
327 gcc_assert (i
== count
);
328 map
->num_partitions
= i
;
331 BITMAP_FREE (selected
);
335 /* Create a partition view which includes all the used partitions in MAP. If
336 WANT_BASES is true, create the base variable map as well. */
339 partition_view_normal (var_map map
, bool want_bases
)
343 used
= partition_view_init (map
);
344 partition_view_fini (map
, used
);
347 var_map_base_init (map
);
349 var_map_base_fini (map
);
353 /* Create a partition view in MAP which includes just partitions which occur in
354 the bitmap ONLY. If WANT_BASES is true, create the base variable map
358 partition_view_bitmap (var_map map
, bitmap only
, bool want_bases
)
361 bitmap new_partitions
= BITMAP_ALLOC (NULL
);
365 used
= partition_view_init (map
);
366 EXECUTE_IF_SET_IN_BITMAP (only
, 0, x
, bi
)
368 p
= partition_find (map
->var_partition
, x
);
369 gcc_assert (bitmap_bit_p (used
, p
));
370 bitmap_set_bit (new_partitions
, p
);
372 partition_view_fini (map
, new_partitions
);
376 var_map_base_init (map
);
378 var_map_base_fini (map
);
382 /* This function is used to change the representative variable in MAP for VAR's
383 partition to a regular non-ssa variable. This allows partitions to be
384 mapped back to real variables. */
387 change_partition_var (var_map map
, tree var
, int part
)
391 gcc_assert (TREE_CODE (var
) != SSA_NAME
);
394 ann
->out_of_ssa_tag
= 1;
395 VAR_ANN_PARTITION (ann
) = part
;
396 if (map
->view_to_partition
)
397 map
->partition_to_var
[map
->view_to_partition
[part
]] = var
;
401 static inline void mark_all_vars_used (tree
*, void *data
);
403 /* Helper function for mark_all_vars_used, called via walk_tree. */
406 mark_all_vars_used_1 (tree
*tp
, int *walk_subtrees
,
410 enum tree_code_class c
= TREE_CODE_CLASS (TREE_CODE (t
));
413 if (TREE_CODE (t
) == SSA_NAME
)
414 t
= SSA_NAME_VAR (t
);
415 if ((IS_EXPR_CODE_CLASS (c
)
416 || IS_GIMPLE_STMT_CODE_CLASS (c
))
417 && (b
= TREE_BLOCK (t
)) != NULL
)
418 TREE_USED (b
) = true;
420 /* Ignore TREE_ORIGINAL for TARGET_MEM_REFS, as well as other
421 fields that do not contain vars. */
422 if (TREE_CODE (t
) == TARGET_MEM_REF
)
424 mark_all_vars_used (&TMR_SYMBOL (t
), data
);
425 mark_all_vars_used (&TMR_BASE (t
), data
);
426 mark_all_vars_used (&TMR_INDEX (t
), data
);
431 /* Only need to mark VAR_DECLS; parameters and return results are not
432 eliminated as unused. */
433 if (TREE_CODE (t
) == VAR_DECL
)
435 if (data
!= NULL
&& bitmap_bit_p ((bitmap
) data
, DECL_UID (t
)))
437 bitmap_clear_bit ((bitmap
) data
, DECL_UID (t
));
438 mark_all_vars_used (&DECL_INITIAL (t
), data
);
443 if (IS_TYPE_OR_DECL_P (t
))
449 /* Mark the scope block SCOPE and its subblocks unused when they can be
450 possibly eliminated if dead. */
453 mark_scope_block_unused (tree scope
)
456 TREE_USED (scope
) = false;
457 if (!(*debug_hooks
->ignore_block
) (scope
))
458 TREE_USED (scope
) = true;
459 for (t
= BLOCK_SUBBLOCKS (scope
); t
; t
= BLOCK_CHAIN (t
))
460 mark_scope_block_unused (t
);
463 /* Look if the block is dead (by possibly eliminating its dead subblocks)
464 and return true if so.
465 Block is declared dead if:
466 1) No statements are associated with it.
467 2) Declares no live variables
468 3) All subblocks are dead
469 or there is precisely one subblocks and the block
470 has same abstract origin as outer block and declares
471 no variables, so it is pure wrapper.
472 When we are not outputting full debug info, we also eliminate dead variables
473 out of scope blocks to let them to be recycled by GGC and to save copying work
474 done by the inliner. */
477 remove_unused_scope_block_p (tree scope
)
480 bool unused
= !TREE_USED (scope
);
484 for (t
= &BLOCK_VARS (scope
); *t
; t
= next
)
486 next
= &TREE_CHAIN (*t
);
488 /* Debug info of nested function refers to the block of the
490 if (TREE_CODE (*t
) == FUNCTION_DECL
)
493 /* When we are outputting debug info, we usually want to output
494 info about optimized-out variables in the scope blocks.
495 Exception are the scope blocks not containing any instructions
496 at all so user can't get into the scopes at first place. */
497 else if ((ann
= var_ann (*t
)) != NULL
501 /* When we are not doing full debug info, we however can keep around
502 only the used variables for cfgexpand's memory packing saving quite
504 else if (debug_info_level
== DINFO_LEVEL_NORMAL
505 || debug_info_level
== DINFO_LEVEL_VERBOSE
506 /* Removing declarations before inlining is going to affect
507 DECL_UID that in turn is going to affect hashtables and
509 || !cfun
->after_inlining
)
514 *t
= TREE_CHAIN (*t
);
519 for (t
= &BLOCK_SUBBLOCKS (scope
); *t
;)
520 if (remove_unused_scope_block_p (*t
))
522 if (BLOCK_SUBBLOCKS (*t
))
524 tree next
= BLOCK_CHAIN (*t
);
525 tree supercontext
= BLOCK_SUPERCONTEXT (*t
);
526 *t
= BLOCK_SUBBLOCKS (*t
);
527 gcc_assert (!BLOCK_CHAIN (*t
));
528 BLOCK_CHAIN (*t
) = next
;
529 BLOCK_SUPERCONTEXT (*t
) = supercontext
;
530 t
= &BLOCK_CHAIN (*t
);
535 gcc_assert (!BLOCK_VARS (*t
));
536 *t
= BLOCK_CHAIN (*t
);
541 t
= &BLOCK_CHAIN (*t
);
544 /* Outer scope is always used. */
545 if (!BLOCK_SUPERCONTEXT (scope
)
546 || TREE_CODE (BLOCK_SUPERCONTEXT (scope
)) == FUNCTION_DECL
)
548 /* If there are more than one live subblocks, it is used. */
549 else if (nsubblocks
> 1)
551 /* When there is only one subblock, see if it is just wrapper we can
552 ignore. Wrappers are not declaring any variables and not changing
554 else if (nsubblocks
== 1
555 && (BLOCK_VARS (scope
)
556 || ((debug_info_level
== DINFO_LEVEL_NORMAL
557 || debug_info_level
== DINFO_LEVEL_VERBOSE
)
558 && ((BLOCK_ABSTRACT_ORIGIN (scope
)
559 != BLOCK_ABSTRACT_ORIGIN (BLOCK_SUPERCONTEXT (scope
)))))))
564 /* Mark all VAR_DECLS under *EXPR_P as used, so that they won't be
565 eliminated during the tree->rtl conversion process. */
568 mark_all_vars_used (tree
*expr_p
, void *data
)
570 walk_tree (expr_p
, mark_all_vars_used_1
, data
, NULL
);
574 /* Remove local variables that are not referenced in the IL. */
577 remove_unused_locals (void)
581 referenced_var_iterator rvi
;
583 bitmap global_unused_vars
= NULL
;
586 mark_scope_block_unused (DECL_INITIAL (current_function_decl
));
587 /* Assume all locals are unused. */
588 FOR_EACH_REFERENCED_VAR (t
, rvi
)
589 var_ann (t
)->used
= false;
591 /* Walk the CFG marking all referenced symbols. */
594 block_stmt_iterator bsi
;
597 /* Walk the statements. */
598 for (bsi
= bsi_start (bb
); !bsi_end_p (bsi
); bsi_next (&bsi
))
599 mark_all_vars_used (bsi_stmt_ptr (bsi
), NULL
);
601 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
606 /* No point processing globals. */
607 if (is_global_var (SSA_NAME_VAR (PHI_RESULT (phi
))))
610 def
= PHI_RESULT (phi
);
611 mark_all_vars_used (&def
, NULL
);
613 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_ALL_USES
)
615 tree arg
= USE_FROM_PTR (arg_p
);
616 mark_all_vars_used (&arg
, NULL
);
621 /* Remove unmarked local vars from local_decls. */
622 for (cell
= &cfun
->local_decls
; *cell
; )
624 tree var
= TREE_VALUE (*cell
);
626 if (TREE_CODE (var
) != FUNCTION_DECL
627 && (!(ann
= var_ann (var
))
630 if (is_global_var (var
))
632 if (global_unused_vars
== NULL
)
633 global_unused_vars
= BITMAP_ALLOC (NULL
);
634 bitmap_set_bit (global_unused_vars
, DECL_UID (var
));
638 *cell
= TREE_CHAIN (*cell
);
642 cell
= &TREE_CHAIN (*cell
);
645 /* Remove unmarked global vars from local_decls. */
646 if (global_unused_vars
!= NULL
)
648 for (t
= cfun
->local_decls
; t
; t
= TREE_CHAIN (t
))
650 tree var
= TREE_VALUE (t
);
652 if (TREE_CODE (var
) == VAR_DECL
653 && is_global_var (var
)
654 && (ann
= var_ann (var
)) != NULL
656 mark_all_vars_used (&DECL_INITIAL (var
), global_unused_vars
);
659 for (cell
= &cfun
->local_decls
; *cell
; )
661 tree var
= TREE_VALUE (*cell
);
663 if (TREE_CODE (var
) == VAR_DECL
664 && is_global_var (var
)
665 && bitmap_bit_p (global_unused_vars
, DECL_UID (var
))
666 && (optimize
|| DECL_ARTIFICIAL (var
)))
667 *cell
= TREE_CHAIN (*cell
);
669 cell
= &TREE_CHAIN (*cell
);
671 BITMAP_FREE (global_unused_vars
);
674 /* Remove unused variables from REFERENCED_VARs. As a special
675 exception keep the variables that are believed to be aliased.
676 Those can't be easily removed from the alias sets and operand
677 caches. They will be removed shortly after the next may_alias
678 pass is performed. */
679 FOR_EACH_REFERENCED_VAR (t
, rvi
)
680 if (!is_global_var (t
)
682 && TREE_CODE (t
) != PARM_DECL
683 && TREE_CODE (t
) != RESULT_DECL
684 && !(ann
= var_ann (t
))->used
685 && !ann
->symbol_mem_tag
686 && !TREE_ADDRESSABLE (t
)
687 && (optimize
|| DECL_ARTIFICIAL (t
)))
688 remove_referenced_var (t
);
690 remove_unused_scope_block_p (DECL_INITIAL (current_function_decl
));
694 /* Allocate and return a new live range information object base on MAP. */
696 static tree_live_info_p
697 new_tree_live_info (var_map map
)
699 tree_live_info_p live
;
702 live
= (tree_live_info_p
) xmalloc (sizeof (struct tree_live_info_d
));
704 live
->num_blocks
= last_basic_block
;
706 live
->livein
= (bitmap
*)xmalloc (last_basic_block
* sizeof (bitmap
));
707 for (x
= 0; x
< (unsigned)last_basic_block
; x
++)
708 live
->livein
[x
] = BITMAP_ALLOC (NULL
);
710 live
->liveout
= (bitmap
*)xmalloc (last_basic_block
* sizeof (bitmap
));
711 for (x
= 0; x
< (unsigned)last_basic_block
; x
++)
712 live
->liveout
[x
] = BITMAP_ALLOC (NULL
);
714 live
->work_stack
= XNEWVEC (int, last_basic_block
);
715 live
->stack_top
= live
->work_stack
;
717 live
->global
= BITMAP_ALLOC (NULL
);
722 /* Free storage for live range info object LIVE. */
725 delete_tree_live_info (tree_live_info_p live
)
729 BITMAP_FREE (live
->global
);
730 free (live
->work_stack
);
732 for (x
= live
->num_blocks
- 1; x
>= 0; x
--)
733 BITMAP_FREE (live
->liveout
[x
]);
734 free (live
->liveout
);
736 for (x
= live
->num_blocks
- 1; x
>= 0; x
--)
737 BITMAP_FREE (live
->livein
[x
]);
744 /* Visit basic block BB and propagate any required live on entry bits from
745 LIVE into the predecessors. VISITED is the bitmap of visited blocks.
746 TMP is a temporary work bitmap which is passed in to avoid reallocating
750 loe_visit_block (tree_live_info_p live
, basic_block bb
, sbitmap visited
,
758 gcc_assert (!TEST_BIT (visited
, bb
->index
));
760 SET_BIT (visited
, bb
->index
);
761 loe
= live_on_entry (live
, bb
);
763 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
766 if (pred_bb
== ENTRY_BLOCK_PTR
)
768 /* TMP is variables live-on-entry from BB that aren't defined in the
769 predecessor block. This should be the live on entry vars to pred.
770 Note that liveout is the DEFs in a block while live on entry is
772 bitmap_and_compl (tmp
, loe
, live
->liveout
[pred_bb
->index
]);
774 /* Add these bits to live-on-entry for the pred. if there are any
775 changes, and pred_bb has been visited already, add it to the
777 change
= bitmap_ior_into (live_on_entry (live
, pred_bb
), tmp
);
778 if (TEST_BIT (visited
, pred_bb
->index
) && change
)
780 RESET_BIT (visited
, pred_bb
->index
);
781 *(live
->stack_top
)++ = pred_bb
->index
;
787 /* Using LIVE, fill in all the live-on-entry blocks between the defs and uses
788 of all the variables. */
791 live_worklist (tree_live_info_p live
)
795 sbitmap visited
= sbitmap_alloc (last_basic_block
+ 1);
796 bitmap tmp
= BITMAP_ALLOC (NULL
);
798 sbitmap_zero (visited
);
800 /* Visit all the blocks in reverse order and propagate live on entry values
801 into the predecessors blocks. */
802 FOR_EACH_BB_REVERSE (bb
)
803 loe_visit_block (live
, bb
, visited
, tmp
);
805 /* Process any blocks which require further iteration. */
806 while (live
->stack_top
!= live
->work_stack
)
808 b
= *--(live
->stack_top
);
809 loe_visit_block (live
, BASIC_BLOCK (b
), visited
, tmp
);
813 sbitmap_free (visited
);
817 /* Calculate the initial live on entry vector for SSA_NAME using immediate_use
818 links. Set the live on entry fields in LIVE. Def's are marked temporarily
819 in the liveout vector. */
822 set_var_live_on_entry (tree ssa_name
, tree_live_info_p live
)
827 basic_block def_bb
= NULL
;
828 imm_use_iterator imm_iter
;
831 p
= var_to_partition (live
->map
, ssa_name
);
832 if (p
== NO_PARTITION
)
835 stmt
= SSA_NAME_DEF_STMT (ssa_name
);
838 def_bb
= bb_for_stmt (stmt
);
839 /* Mark defs in liveout bitmap temporarily. */
841 bitmap_set_bit (live
->liveout
[def_bb
->index
], p
);
844 def_bb
= ENTRY_BLOCK_PTR
;
846 /* Visit each use of SSA_NAME and if it isn't in the same block as the def,
847 add it to the list of live on entry blocks. */
848 FOR_EACH_IMM_USE_FAST (use
, imm_iter
, ssa_name
)
850 tree use_stmt
= USE_STMT (use
);
851 basic_block add_block
= NULL
;
853 if (TREE_CODE (use_stmt
) == PHI_NODE
)
855 /* Uses in PHI's are considered to be live at exit of the SRC block
856 as this is where a copy would be inserted. Check to see if it is
857 defined in that block, or whether its live on entry. */
858 int index
= PHI_ARG_INDEX_FROM_USE (use
);
859 edge e
= PHI_ARG_EDGE (use_stmt
, index
);
860 if (e
->src
!= ENTRY_BLOCK_PTR
)
862 if (e
->src
!= def_bb
)
868 /* If its not defined in this block, its live on entry. */
869 basic_block use_bb
= bb_for_stmt (use_stmt
);
870 if (use_bb
!= def_bb
)
874 /* If there was a live on entry use, set the bit. */
878 bitmap_set_bit (live
->livein
[add_block
->index
], p
);
882 /* If SSA_NAME is live on entry to at least one block, fill in all the live
883 on entry blocks between the def and all the uses. */
885 bitmap_set_bit (live
->global
, p
);
889 /* Calculate the live on exit vectors based on the entry info in LIVEINFO. */
892 calculate_live_on_exit (tree_live_info_p liveinfo
)
901 /* live on entry calculations used liveout vectors for defs, clear them. */
903 bitmap_clear (liveinfo
->liveout
[bb
->index
]);
905 /* Set all the live-on-exit bits for uses in PHIs. */
908 /* Mark the PHI arguments which are live on exit to the pred block. */
909 for (phi
= phi_nodes (bb
); phi
; phi
= PHI_CHAIN (phi
))
910 for (i
= 0; i
< (unsigned)PHI_NUM_ARGS (phi
); i
++)
912 t
= PHI_ARG_DEF (phi
, i
);
913 if (TREE_CODE (t
) != SSA_NAME
)
915 p
= var_to_partition (liveinfo
->map
, t
);
916 if (p
== NO_PARTITION
)
918 e
= PHI_ARG_EDGE (phi
, i
);
919 if (e
->src
!= ENTRY_BLOCK_PTR
)
920 bitmap_set_bit (liveinfo
->liveout
[e
->src
->index
], p
);
923 /* Add each successors live on entry to this bock live on exit. */
924 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
925 if (e
->dest
!= EXIT_BLOCK_PTR
)
926 bitmap_ior_into (liveinfo
->liveout
[bb
->index
],
927 live_on_entry (liveinfo
, e
->dest
));
932 /* Given partition map MAP, calculate all the live on entry bitmaps for
933 each partition. Return a new live info object. */
936 calculate_live_ranges (var_map map
)
940 tree_live_info_p live
;
942 live
= new_tree_live_info (map
);
943 for (i
= 0; i
< num_var_partitions (map
); i
++)
945 var
= partition_to_var (map
, i
);
946 if (var
!= NULL_TREE
)
947 set_var_live_on_entry (var
, live
);
950 live_worklist (live
);
952 #ifdef ENABLE_CHECKING
953 verify_live_on_entry (live
);
956 calculate_live_on_exit (live
);
961 /* Output partition map MAP to file F. */
964 dump_var_map (FILE *f
, var_map map
)
970 fprintf (f
, "\nPartition map \n\n");
972 for (x
= 0; x
< map
->num_partitions
; x
++)
974 if (map
->view_to_partition
!= NULL
)
975 p
= map
->view_to_partition
[x
];
979 if (map
->partition_to_var
[p
] == NULL_TREE
)
983 for (y
= 1; y
< num_ssa_names
; y
++)
985 p
= partition_find (map
->var_partition
, y
);
986 if (map
->partition_to_view
)
987 p
= map
->partition_to_view
[p
];
992 fprintf(f
, "Partition %d (", x
);
993 print_generic_expr (f
, partition_to_var (map
, p
), TDF_SLIM
);
996 fprintf (f
, "%d ", y
);
1006 /* Output live range info LIVE to file F, controlled by FLAG. */
1009 dump_live_info (FILE *f
, tree_live_info_p live
, int flag
)
1013 var_map map
= live
->map
;
1016 if ((flag
& LIVEDUMP_ENTRY
) && live
->livein
)
1020 fprintf (f
, "\nLive on entry to BB%d : ", bb
->index
);
1021 EXECUTE_IF_SET_IN_BITMAP (live
->livein
[bb
->index
], 0, i
, bi
)
1023 print_generic_expr (f
, partition_to_var (map
, i
), TDF_SLIM
);
1030 if ((flag
& LIVEDUMP_EXIT
) && live
->liveout
)
1034 fprintf (f
, "\nLive on exit from BB%d : ", bb
->index
);
1035 EXECUTE_IF_SET_IN_BITMAP (live
->liveout
[bb
->index
], 0, i
, bi
)
1037 print_generic_expr (f
, partition_to_var (map
, i
), TDF_SLIM
);
1046 #ifdef ENABLE_CHECKING
1047 /* Verify that SSA_VAR is a non-virtual SSA_NAME. */
1050 register_ssa_partition_check (tree ssa_var
)
1052 gcc_assert (TREE_CODE (ssa_var
) == SSA_NAME
);
1053 if (!is_gimple_reg (SSA_NAME_VAR (ssa_var
)))
1055 fprintf (stderr
, "Illegally registering a virtual SSA name :");
1056 print_generic_expr (stderr
, ssa_var
, TDF_SLIM
);
1057 fprintf (stderr
, " in the SSA->Normal phase.\n");
1058 internal_error ("SSA corruption");
1063 /* Verify that the info in LIVE matches the current cfg. */
1066 verify_live_on_entry (tree_live_info_p live
)
1075 var_map map
= live
->map
;
1077 /* Check for live on entry partitions and report those with a DEF in
1078 the program. This will typically mean an optimization has done
1080 bb
= ENTRY_BLOCK_PTR
;
1082 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
1084 int entry_block
= e
->dest
->index
;
1085 if (e
->dest
== EXIT_BLOCK_PTR
)
1087 for (i
= 0; i
< (unsigned)num_var_partitions (map
); i
++)
1092 var
= partition_to_var (map
, i
);
1093 stmt
= SSA_NAME_DEF_STMT (var
);
1094 tmp
= bb_for_stmt (stmt
);
1095 d
= gimple_default_def (cfun
, SSA_NAME_VAR (var
));
1097 loe
= live_on_entry (live
, e
->dest
);
1098 if (loe
&& bitmap_bit_p (loe
, i
))
1100 if (!IS_EMPTY_STMT (stmt
))
1103 print_generic_expr (stderr
, var
, TDF_SLIM
);
1104 fprintf (stderr
, " is defined ");
1106 fprintf (stderr
, " in BB%d, ", tmp
->index
);
1107 fprintf (stderr
, "by:\n");
1108 print_generic_expr (stderr
, stmt
, TDF_SLIM
);
1109 fprintf (stderr
, "\nIt is also live-on-entry to entry BB %d",
1111 fprintf (stderr
, " So it appears to have multiple defs.\n");
1118 print_generic_expr (stderr
, var
, TDF_SLIM
);
1119 fprintf (stderr
, " is live-on-entry to BB%d ",entry_block
);
1122 fprintf (stderr
, " but is not the default def of ");
1123 print_generic_expr (stderr
, d
, TDF_SLIM
);
1124 fprintf (stderr
, "\n");
1127 fprintf (stderr
, " and there is no default def.\n");
1134 /* The only way this var shouldn't be marked live on entry is
1135 if it occurs in a PHI argument of the block. */
1137 for (phi
= phi_nodes (e
->dest
);
1139 phi
= PHI_CHAIN (phi
))
1141 for (z
= 0; z
< PHI_NUM_ARGS (phi
); z
++)
1142 if (var
== PHI_ARG_DEF (phi
, z
))
1151 print_generic_expr (stderr
, var
, TDF_SLIM
);
1152 fprintf (stderr
, " is not marked live-on-entry to entry BB%d ",
1154 fprintf (stderr
, "but it is a default def so it should be.\n");
1158 gcc_assert (num
<= 0);