1 /* Liveness for SSA trees.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009 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, void *data)
409 enum tree_code_class c = TREE_CODE_CLASS (TREE_CODE (t));
412 if (TREE_CODE (t) == SSA_NAME)
413 t = SSA_NAME_VAR (t);
415 if (IS_EXPR_CODE_CLASS (c)
416 && (b = TREE_BLOCK (t)) != NULL)
417 TREE_USED (b) = true;
419 /* Ignore TREE_ORIGINAL for TARGET_MEM_REFS, as well as other
420 fields that do not contain vars. */
421 if (TREE_CODE (t) == TARGET_MEM_REF)
423 mark_all_vars_used (&TMR_SYMBOL (t), data);
424 mark_all_vars_used (&TMR_BASE (t), data);
425 mark_all_vars_used (&TMR_INDEX (t), data);
430 /* Only need to mark VAR_DECLS; parameters and return results are not
431 eliminated as unused. */
432 if (TREE_CODE (t) == VAR_DECL)
434 if (data != NULL && bitmap_bit_p ((bitmap) data, DECL_UID (t)))
436 bitmap_clear_bit ((bitmap) data, DECL_UID (t));
437 mark_all_vars_used (&DECL_INITIAL (t), data);
442 if (IS_TYPE_OR_DECL_P (t))
448 /* Mark the scope block SCOPE and its subblocks unused when they can be
449 possibly eliminated if dead. */
452 mark_scope_block_unused (tree scope)
455 TREE_USED (scope) = false;
456 if (!(*debug_hooks->ignore_block) (scope))
457 TREE_USED (scope) = true;
458 for (t = BLOCK_SUBBLOCKS (scope); t ; t = BLOCK_CHAIN (t))
459 mark_scope_block_unused (t);
462 /* Look if the block is dead (by possibly eliminating its dead subblocks)
463 and return true if so.
464 Block is declared dead if:
465 1) No statements are associated with it.
466 2) Declares no live variables
467 3) All subblocks are dead
468 or there is precisely one subblocks and the block
469 has same abstract origin as outer block and declares
470 no variables, so it is pure wrapper.
471 When we are not outputting full debug info, we also eliminate dead variables
472 out of scope blocks to let them to be recycled by GGC and to save copying work
473 done by the inliner. */
476 remove_unused_scope_block_p (tree scope)
479 bool unused = !TREE_USED (scope);
483 for (t = &BLOCK_VARS (scope); *t; t = next)
485 next = &TREE_CHAIN (*t);
487 /* Debug info of nested function refers to the block of the
489 if (TREE_CODE (*t) == FUNCTION_DECL)
492 /* Remove everything we don't generate debug info for. */
493 else if (DECL_IGNORED_P (*t))
495 *t = TREE_CHAIN (*t);
499 /* When we are outputting debug info, we usually want to output
500 info about optimized-out variables in the scope blocks.
501 Exception are the scope blocks not containing any instructions
502 at all so user can't get into the scopes at first place. */
503 else if ((ann = var_ann (*t)) != NULL
507 /* When we are not doing full debug info, we however can keep around
508 only the used variables for cfgexpand's memory packing saving quite
510 else if (debug_info_level == DINFO_LEVEL_NORMAL
511 || debug_info_level == DINFO_LEVEL_VERBOSE
512 /* Removing declarations before inlining is going to affect
513 DECL_UID that in turn is going to affect hashtables and
515 || !cfun->after_inlining)
520 *t = TREE_CHAIN (*t);
525 for (t = &BLOCK_SUBBLOCKS (scope); *t ;)
526 if (remove_unused_scope_block_p (*t))
528 if (BLOCK_SUBBLOCKS (*t))
530 tree next = BLOCK_CHAIN (*t);
531 tree supercontext = BLOCK_SUPERCONTEXT (*t);
532 *t = BLOCK_SUBBLOCKS (*t);
533 gcc_assert (!BLOCK_CHAIN (*t));
534 BLOCK_CHAIN (*t) = next;
535 BLOCK_SUPERCONTEXT (*t) = supercontext;
536 t = &BLOCK_CHAIN (*t);
541 gcc_assert (!BLOCK_VARS (*t));
542 *t = BLOCK_CHAIN (*t);
547 t = &BLOCK_CHAIN (*t);
550 /* Outer scope is always used. */
551 if (!BLOCK_SUPERCONTEXT (scope)
552 || TREE_CODE (BLOCK_SUPERCONTEXT (scope)) == FUNCTION_DECL)
554 /* If there are more than one live subblocks, it is used. */
555 else if (nsubblocks > 1)
557 /* When there is only one subblock, see if it is just wrapper we can
558 ignore. Wrappers are not declaring any variables and not changing
560 else if (nsubblocks == 1
561 && (BLOCK_VARS (scope)
562 || ((debug_info_level == DINFO_LEVEL_NORMAL
563 || debug_info_level == DINFO_LEVEL_VERBOSE)
564 && ((BLOCK_ABSTRACT_ORIGIN (scope)
565 != BLOCK_ABSTRACT_ORIGIN (BLOCK_SUPERCONTEXT (scope)))))))
570 /* Mark all VAR_DECLS under *EXPR_P as used, so that they won't be
571 eliminated during the tree->rtl conversion process. */
574 mark_all_vars_used (tree *expr_p, void *data)
576 walk_tree (expr_p, mark_all_vars_used_1, data, NULL);
580 /* Remove local variables that are not referenced in the IL. */
583 remove_unused_locals (void)
587 referenced_var_iterator rvi;
589 bitmap global_unused_vars = NULL;
592 mark_scope_block_unused (DECL_INITIAL (current_function_decl));
594 /* Assume all locals are unused. */
595 FOR_EACH_REFERENCED_VAR (t, rvi)
596 var_ann (t)->used = false;
598 /* Walk the CFG marking all referenced symbols. */
601 gimple_stmt_iterator gsi;
606 /* Walk the statements. */
607 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
609 gimple stmt = gsi_stmt (gsi);
610 tree b = gimple_block (stmt);
613 TREE_USED (b) = true;
615 for (i = 0; i < gimple_num_ops (stmt); i++)
616 mark_all_vars_used (gimple_op_ptr (gsi_stmt (gsi), i), NULL);
619 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
624 gimple phi = gsi_stmt (gsi);
626 /* No point processing globals. */
627 if (is_global_var (SSA_NAME_VAR (gimple_phi_result (phi))))
630 def = gimple_phi_result (phi);
631 mark_all_vars_used (&def, NULL);
633 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_ALL_USES)
635 tree arg = USE_FROM_PTR (arg_p);
636 mark_all_vars_used (&arg, NULL);
640 FOR_EACH_EDGE (e, ei, bb->succs)
642 TREE_USED (e->goto_block) = true;
645 cfun->has_local_explicit_reg_vars = false;
647 /* Remove unmarked local vars from local_decls. */
648 for (cell = &cfun->local_decls; *cell; )
650 tree var = TREE_VALUE (*cell);
652 if (TREE_CODE (var) != FUNCTION_DECL
653 && (!(ann = var_ann (var))
656 if (is_global_var (var))
658 if (global_unused_vars == NULL)
659 global_unused_vars = BITMAP_ALLOC (NULL);
660 bitmap_set_bit (global_unused_vars, DECL_UID (var));
664 *cell = TREE_CHAIN (*cell);
668 else if (TREE_CODE (var) == VAR_DECL
669 && DECL_HARD_REGISTER (var)
670 && !is_global_var (var))
671 cfun->has_local_explicit_reg_vars = true;
672 cell = &TREE_CHAIN (*cell);
675 /* Remove unmarked global vars from local_decls. */
676 if (global_unused_vars != NULL)
678 for (t = cfun->local_decls; t; t = TREE_CHAIN (t))
680 tree var = TREE_VALUE (t);
682 if (TREE_CODE (var) == VAR_DECL
683 && is_global_var (var)
684 && (ann = var_ann (var)) != NULL
686 mark_all_vars_used (&DECL_INITIAL (var), global_unused_vars);
689 for (cell = &cfun->local_decls; *cell; )
691 tree var = TREE_VALUE (*cell);
693 if (TREE_CODE (var) == VAR_DECL
694 && is_global_var (var)
695 && bitmap_bit_p (global_unused_vars, DECL_UID (var))
696 && (optimize || DECL_ARTIFICIAL (var)))
697 *cell = TREE_CHAIN (*cell);
699 cell = &TREE_CHAIN (*cell);
701 BITMAP_FREE (global_unused_vars);
704 /* Remove unused variables from REFERENCED_VARs. As a special
705 exception keep the variables that are believed to be aliased.
706 Those can't be easily removed from the alias sets and operand
707 caches. They will be removed shortly after the next may_alias
708 pass is performed. */
709 FOR_EACH_REFERENCED_VAR (t, rvi)
710 if (!is_global_var (t)
712 && TREE_CODE (t) != PARM_DECL
713 && TREE_CODE (t) != RESULT_DECL
714 && !(ann = var_ann (t))->used
715 && !ann->symbol_mem_tag
716 && !TREE_ADDRESSABLE (t)
717 && (optimize || DECL_ARTIFICIAL (t)))
718 remove_referenced_var (t);
720 remove_unused_scope_block_p (DECL_INITIAL (current_function_decl));
724 /* Allocate and return a new live range information object base on MAP. */
726 static tree_live_info_p
727 new_tree_live_info (var_map map)
729 tree_live_info_p live;
732 live = (tree_live_info_p) xmalloc (sizeof (struct tree_live_info_d));
734 live->num_blocks = last_basic_block;
736 live->livein = (bitmap *)xmalloc (last_basic_block * sizeof (bitmap));
737 for (x = 0; x < (unsigned)last_basic_block; x++)
738 live->livein[x] = BITMAP_ALLOC (NULL);
740 live->liveout = (bitmap *)xmalloc (last_basic_block * sizeof (bitmap));
741 for (x = 0; x < (unsigned)last_basic_block; x++)
742 live->liveout[x] = BITMAP_ALLOC (NULL);
744 live->work_stack = XNEWVEC (int, last_basic_block);
745 live->stack_top = live->work_stack;
747 live->global = BITMAP_ALLOC (NULL);
752 /* Free storage for live range info object LIVE. */
755 delete_tree_live_info (tree_live_info_p live)
759 BITMAP_FREE (live->global);
760 free (live->work_stack);
762 for (x = live->num_blocks - 1; x >= 0; x--)
763 BITMAP_FREE (live->liveout[x]);
764 free (live->liveout);
766 for (x = live->num_blocks - 1; x >= 0; x--)
767 BITMAP_FREE (live->livein[x]);
774 /* Visit basic block BB and propagate any required live on entry bits from
775 LIVE into the predecessors. VISITED is the bitmap of visited blocks.
776 TMP is a temporary work bitmap which is passed in to avoid reallocating
780 loe_visit_block (tree_live_info_p live, basic_block bb, sbitmap visited,
788 gcc_assert (!TEST_BIT (visited, bb->index));
790 SET_BIT (visited, bb->index);
791 loe = live_on_entry (live, bb);
793 FOR_EACH_EDGE (e, ei, bb->preds)
796 if (pred_bb == ENTRY_BLOCK_PTR)
798 /* TMP is variables live-on-entry from BB that aren't defined in the
799 predecessor block. This should be the live on entry vars to pred.
800 Note that liveout is the DEFs in a block while live on entry is
802 bitmap_and_compl (tmp, loe, live->liveout[pred_bb->index]);
804 /* Add these bits to live-on-entry for the pred. if there are any
805 changes, and pred_bb has been visited already, add it to the
807 change = bitmap_ior_into (live_on_entry (live, pred_bb), tmp);
808 if (TEST_BIT (visited, pred_bb->index) && change)
810 RESET_BIT (visited, pred_bb->index);
811 *(live->stack_top)++ = pred_bb->index;
817 /* Using LIVE, fill in all the live-on-entry blocks between the defs and uses
818 of all the variables. */
821 live_worklist (tree_live_info_p live)
825 sbitmap visited = sbitmap_alloc (last_basic_block + 1);
826 bitmap tmp = BITMAP_ALLOC (NULL);
828 sbitmap_zero (visited);
830 /* Visit all the blocks in reverse order and propagate live on entry values
831 into the predecessors blocks. */
832 FOR_EACH_BB_REVERSE (bb)
833 loe_visit_block (live, bb, visited, tmp);
835 /* Process any blocks which require further iteration. */
836 while (live->stack_top != live->work_stack)
838 b = *--(live->stack_top);
839 loe_visit_block (live, BASIC_BLOCK (b), visited, tmp);
843 sbitmap_free (visited);
847 /* Calculate the initial live on entry vector for SSA_NAME using immediate_use
848 links. Set the live on entry fields in LIVE. Def's are marked temporarily
849 in the liveout vector. */
852 set_var_live_on_entry (tree ssa_name, tree_live_info_p live)
857 basic_block def_bb = NULL;
858 imm_use_iterator imm_iter;
861 p = var_to_partition (live->map, ssa_name);
862 if (p == NO_PARTITION)
865 stmt = SSA_NAME_DEF_STMT (ssa_name);
868 def_bb = gimple_bb (stmt);
869 /* Mark defs in liveout bitmap temporarily. */
871 bitmap_set_bit (live->liveout[def_bb->index], p);
874 def_bb = ENTRY_BLOCK_PTR;
876 /* Visit each use of SSA_NAME and if it isn't in the same block as the def,
877 add it to the list of live on entry blocks. */
878 FOR_EACH_IMM_USE_FAST (use, imm_iter, ssa_name)
880 gimple use_stmt = USE_STMT (use);
881 basic_block add_block = NULL;
883 if (gimple_code (use_stmt) == GIMPLE_PHI)
885 /* Uses in PHI's are considered to be live at exit of the SRC block
886 as this is where a copy would be inserted. Check to see if it is
887 defined in that block, or whether its live on entry. */
888 int index = PHI_ARG_INDEX_FROM_USE (use);
889 edge e = gimple_phi_arg_edge (use_stmt, index);
890 if (e->src != ENTRY_BLOCK_PTR)
892 if (e->src != def_bb)
898 /* If its not defined in this block, its live on entry. */
899 basic_block use_bb = gimple_bb (use_stmt);
900 if (use_bb != def_bb)
904 /* If there was a live on entry use, set the bit. */
908 bitmap_set_bit (live->livein[add_block->index], p);
912 /* If SSA_NAME is live on entry to at least one block, fill in all the live
913 on entry blocks between the def and all the uses. */
915 bitmap_set_bit (live->global, p);
919 /* Calculate the live on exit vectors based on the entry info in LIVEINFO. */
922 calculate_live_on_exit (tree_live_info_p liveinfo)
928 /* live on entry calculations used liveout vectors for defs, clear them. */
930 bitmap_clear (liveinfo->liveout[bb->index]);
932 /* Set all the live-on-exit bits for uses in PHIs. */
935 gimple_stmt_iterator gsi;
938 /* Mark the PHI arguments which are live on exit to the pred block. */
939 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
941 gimple phi = gsi_stmt (gsi);
942 for (i = 0; i < gimple_phi_num_args (phi); i++)
944 tree t = PHI_ARG_DEF (phi, i);
947 if (TREE_CODE (t) != SSA_NAME)
950 p = var_to_partition (liveinfo->map, t);
951 if (p == NO_PARTITION)
953 e = gimple_phi_arg_edge (phi, i);
954 if (e->src != ENTRY_BLOCK_PTR)
955 bitmap_set_bit (liveinfo->liveout[e->src->index], p);
959 /* Add each successors live on entry to this bock live on exit. */
960 FOR_EACH_EDGE (e, ei, bb->succs)
961 if (e->dest != EXIT_BLOCK_PTR)
962 bitmap_ior_into (liveinfo->liveout[bb->index],
963 live_on_entry (liveinfo, e->dest));
968 /* Given partition map MAP, calculate all the live on entry bitmaps for
969 each partition. Return a new live info object. */
972 calculate_live_ranges (var_map map)
976 tree_live_info_p live;
978 live = new_tree_live_info (map);
979 for (i = 0; i < num_var_partitions (map); i++)
981 var = partition_to_var (map, i);
982 if (var != NULL_TREE)
983 set_var_live_on_entry (var, live);
986 live_worklist (live);
988 #ifdef ENABLE_CHECKING
989 verify_live_on_entry (live);
992 calculate_live_on_exit (live);
997 /* Output partition map MAP to file F. */
1000 dump_var_map (FILE *f, var_map map)
1006 fprintf (f, "\nPartition map \n\n");
1008 for (x = 0; x < map->num_partitions; x++)
1010 if (map->view_to_partition != NULL)
1011 p = map->view_to_partition[x];
1015 if (map->partition_to_var[p] == NULL_TREE)
1019 for (y = 1; y < num_ssa_names; y++)
1021 p = partition_find (map->var_partition, y);
1022 if (map->partition_to_view)
1023 p = map->partition_to_view[p];
1028 fprintf(f, "Partition %d (", x);
1029 print_generic_expr (f, partition_to_var (map, p), TDF_SLIM);
1032 fprintf (f, "%d ", y);
1042 /* Output live range info LIVE to file F, controlled by FLAG. */
1045 dump_live_info (FILE *f, tree_live_info_p live, int flag)
1049 var_map map = live->map;
1052 if ((flag & LIVEDUMP_ENTRY) && live->livein)
1056 fprintf (f, "\nLive on entry to BB%d : ", bb->index);
1057 EXECUTE_IF_SET_IN_BITMAP (live->livein[bb->index], 0, i, bi)
1059 print_generic_expr (f, partition_to_var (map, i), TDF_SLIM);
1066 if ((flag & LIVEDUMP_EXIT) && live->liveout)
1070 fprintf (f, "\nLive on exit from BB%d : ", bb->index);
1071 EXECUTE_IF_SET_IN_BITMAP (live->liveout[bb->index], 0, i, bi)
1073 print_generic_expr (f, partition_to_var (map, i), TDF_SLIM);
1082 #ifdef ENABLE_CHECKING
1083 /* Verify that SSA_VAR is a non-virtual SSA_NAME. */
1086 register_ssa_partition_check (tree ssa_var)
1088 gcc_assert (TREE_CODE (ssa_var) == SSA_NAME);
1089 if (!is_gimple_reg (SSA_NAME_VAR (ssa_var)))
1091 fprintf (stderr, "Illegally registering a virtual SSA name :");
1092 print_generic_expr (stderr, ssa_var, TDF_SLIM);
1093 fprintf (stderr, " in the SSA->Normal phase.\n");
1094 internal_error ("SSA corruption");
1099 /* Verify that the info in LIVE matches the current cfg. */
1102 verify_live_on_entry (tree_live_info_p live)
1111 var_map map = live->map;
1113 /* Check for live on entry partitions and report those with a DEF in
1114 the program. This will typically mean an optimization has done
1116 bb = ENTRY_BLOCK_PTR;
1118 FOR_EACH_EDGE (e, ei, bb->succs)
1120 int entry_block = e->dest->index;
1121 if (e->dest == EXIT_BLOCK_PTR)
1123 for (i = 0; i < (unsigned)num_var_partitions (map); i++)
1128 var = partition_to_var (map, i);
1129 stmt = SSA_NAME_DEF_STMT (var);
1130 tmp = gimple_bb (stmt);
1131 d = gimple_default_def (cfun, SSA_NAME_VAR (var));
1133 loe = live_on_entry (live, e->dest);
1134 if (loe && bitmap_bit_p (loe, i))
1136 if (!gimple_nop_p (stmt))
1139 print_generic_expr (stderr, var, TDF_SLIM);
1140 fprintf (stderr, " is defined ");
1142 fprintf (stderr, " in BB%d, ", tmp->index);
1143 fprintf (stderr, "by:\n");
1144 print_gimple_stmt (stderr, stmt, 0, TDF_SLIM);
1145 fprintf (stderr, "\nIt is also live-on-entry to entry BB %d",
1147 fprintf (stderr, " So it appears to have multiple defs.\n");
1154 print_generic_expr (stderr, var, TDF_SLIM);
1155 fprintf (stderr, " is live-on-entry to BB%d ",
1159 fprintf (stderr, " but is not the default def of ");
1160 print_generic_expr (stderr, d, TDF_SLIM);
1161 fprintf (stderr, "\n");
1164 fprintf (stderr, " and there is no default def.\n");
1171 /* The only way this var shouldn't be marked live on entry is
1172 if it occurs in a PHI argument of the block. */
1175 gimple_stmt_iterator gsi;
1176 for (gsi = gsi_start_phis (e->dest);
1177 !gsi_end_p (gsi) && !ok;
1180 gimple phi = gsi_stmt (gsi);
1181 for (z = 0; z < gimple_phi_num_args (phi); z++)
1182 if (var == gimple_phi_arg_def (phi, z))
1191 print_generic_expr (stderr, var, TDF_SLIM);
1192 fprintf (stderr, " is not marked live-on-entry to entry BB%d ",
1194 fprintf (stderr, "but it is a default def so it should be.\n");
1198 gcc_assert (num <= 0);