1 /* SSA operands management for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to
18 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
19 Boston, MA 02110-1301, USA. */
23 #include "coretypes.h"
28 #include "diagnostic.h"
29 #include "tree-flow.h"
30 #include "tree-inline.h"
31 #include "tree-pass.h"
35 #include "langhooks.h"
36 #include "ipa-reference.h"
38 /* This file contains the code required to manage the operands cache of the
39 SSA optimizer. For every stmt, we maintain an operand cache in the stmt
40 annotation. This cache contains operands that will be of interest to
41 optimizers and other passes wishing to manipulate the IL.
43 The operand type are broken up into REAL and VIRTUAL operands. The real
44 operands are represented as pointers into the stmt's operand tree. Thus
45 any manipulation of the real operands will be reflected in the actual tree.
46 Virtual operands are represented solely in the cache, although the base
47 variable for the SSA_NAME may, or may not occur in the stmt's tree.
48 Manipulation of the virtual operands will not be reflected in the stmt tree.
50 The routines in this file are concerned with creating this operand cache
53 The operand tree is the parsed by the various get_* routines which look
54 through the stmt tree for the occurrence of operands which may be of
55 interest, and calls are made to the append_* routines whenever one is
56 found. There are 4 of these routines, each representing one of the
57 4 types of operands. Defs, Uses, Virtual Uses, and Virtual May Defs.
59 The append_* routines check for duplication, and simply keep a list of
60 unique objects for each operand type in the build_* extendable vectors.
62 Once the stmt tree is completely parsed, the finalize_ssa_operands()
63 routine is called, which proceeds to perform the finalization routine
64 on each of the 4 operand vectors which have been built up.
66 If the stmt had a previous operand cache, the finalization routines
67 attempt to match up the new operands with the old ones. If it's a perfect
68 match, the old vector is simply reused. If it isn't a perfect match, then
69 a new vector is created and the new operands are placed there. For
70 virtual operands, if the previous cache had SSA_NAME version of a
71 variable, and that same variable occurs in the same operands cache, then
72 the new cache vector will also get the same SSA_NAME.
74 i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new operand
75 vector for VUSE, then the new vector will also be modified such that
76 it contains 'a_5' rather than 'a'. */
79 /* Structure storing statistics on how many call clobbers we have, and
80 how many where avoided. */
84 /* Number of call-clobbered ops we attempt to add to calls in
85 add_call_clobbered_mem_symbols. */
86 unsigned int clobbered_vars;
88 /* Number of write-clobbers (VDEFs) avoided by using
89 not_written information. */
90 unsigned int static_write_clobbers_avoided;
92 /* Number of reads (VUSEs) avoided by using not_read information. */
93 unsigned int static_read_clobbers_avoided;
95 /* Number of write-clobbers avoided because the variable can't escape to
97 unsigned int unescapable_clobbers_avoided;
99 /* Number of read-only uses we attempt to add to calls in
100 add_call_read_mem_symbols. */
101 unsigned int readonly_clobbers;
103 /* Number of read-only uses we avoid using not_read information. */
104 unsigned int static_readonly_clobbers_avoided;
108 /* Flags to describe operand properties in helpers. */
110 /* By default, operands are loaded. */
113 /* Operand is the target of an assignment expression or a
114 call-clobbered variable. */
115 #define opf_def (1 << 0)
117 /* No virtual operands should be created in the expression. This is used
118 when traversing ADDR_EXPR nodes which have different semantics than
119 other expressions. Inside an ADDR_EXPR node, the only operands that we
120 need to consider are indices into arrays. For instance, &a.b[i] should
121 generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
123 #define opf_no_vops (1 << 1)
125 /* Operand is an implicit reference. This is used to distinguish
126 explicit assignments in the form of GIMPLE_MODIFY_STMT from
127 clobbering sites like function calls or ASM_EXPRs. */
128 #define opf_implicit (1 << 2)
130 /* Array for building all the def operands. */
131 static VEC(tree,heap) *build_defs;
133 /* Array for building all the use operands. */
134 static VEC(tree,heap) *build_uses;
136 /* Set for building all the VDEF operands. */
137 static VEC(tree,heap) *build_vdefs;
139 /* Set for building all the VUSE operands. */
140 static VEC(tree,heap) *build_vuses;
142 /* Bitmap obstack for our datastructures that needs to survive across
143 compilations of multiple functions. */
144 static bitmap_obstack operands_bitmap_obstack;
146 /* Set for building all the loaded symbols. */
147 static bitmap build_loads;
149 /* Set for building all the stored symbols. */
150 static bitmap build_stores;
152 static void get_expr_operands (tree, tree *, int);
154 /* Number of functions with initialized ssa_operands. */
155 static int n_initialized = 0;
157 /* Statement change buffer. Data structure used to record state
158 information for statements. This is used to determine what needs
159 to be done in order to update the SSA web after a statement is
160 modified by a pass. If STMT is a statement that has just been
161 created, or needs to be folded via fold_stmt, or anything that
162 changes its physical structure then the pass should:
164 1- Call push_stmt_changes (&stmt) to record the current state of
165 STMT before any modifications are made.
167 2- Make all appropriate modifications to the statement.
169 3- Call pop_stmt_changes (&stmt) to find new symbols that
170 need to be put in SSA form, SSA name mappings for names that
171 have disappeared, recompute invariantness for address
172 expressions, cleanup EH information, etc.
174 If it is possible to determine that the statement was not modified,
175 instead of calling pop_stmt_changes it is quicker to call
176 discard_stmt_changes to avoid the expensive and unnecessary operand
177 re-scan and change comparison. */
181 /* Pointer to the statement being modified. */
184 /* If the statement references memory these are the sets of symbols
185 loaded and stored by the statement. */
190 typedef struct scb_d *scb_t;
192 DEF_VEC_ALLOC_P(scb_t,heap);
194 /* Stack of statement change buffers (SCB). Every call to
195 push_stmt_changes pushes a new buffer onto the stack. Calls to
196 pop_stmt_changes pop a buffer off of the stack and compute the set
197 of changes for the popped statement. */
198 static VEC(scb_t,heap) *scb_stack;
200 /* Return the DECL_UID of the base variable of T. */
202 static inline unsigned
203 get_name_decl (tree t)
205 if (TREE_CODE (t) != SSA_NAME)
208 return DECL_UID (SSA_NAME_VAR (t));
212 /* Comparison function for qsort used in operand_build_sort_virtual. */
215 operand_build_cmp (const void *p, const void *q)
217 tree e1 = *((const tree *)p);
218 tree e2 = *((const tree *)q);
221 u1 = get_name_decl (e1);
222 u2 = get_name_decl (e2);
224 /* We want to sort in ascending order. They can never be equal. */
225 #ifdef ENABLE_CHECKING
226 gcc_assert (u1 != u2);
228 return (u1 > u2 ? 1 : -1);
232 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
235 operand_build_sort_virtual (VEC(tree,heap) *list)
237 int num = VEC_length (tree, list);
244 if (get_name_decl (VEC_index (tree, list, 0))
245 > get_name_decl (VEC_index (tree, list, 1)))
247 /* Swap elements if in the wrong order. */
248 tree tmp = VEC_index (tree, list, 0);
249 VEC_replace (tree, list, 0, VEC_index (tree, list, 1));
250 VEC_replace (tree, list, 1, tmp);
255 /* There are 3 or more elements, call qsort. */
256 qsort (VEC_address (tree, list),
257 VEC_length (tree, list),
263 /* Return true if the SSA operands cache is active. */
266 ssa_operands_active (void)
268 return cfun->gimple_df && gimple_ssa_operands (cfun)->ops_active;
272 /* VOPs are of variable sized, so the free list maps "free buckets" to the
285 Any VOPs larger than this are simply added to the largest bucket when they
289 /* Return the number of operands used in bucket BUCKET. */
292 vop_free_bucket_size (int bucket)
294 #ifdef ENABLE_CHECKING
295 gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
299 return (bucket - 13) * 8;
303 /* For a vop of NUM operands, return the bucket NUM belongs to. If NUM is
304 beyond the end of the bucket table, return -1. */
307 vop_free_bucket_index (int num)
309 gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
311 /* Sizes 1 through 16 use buckets 0-15. */
314 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
315 num = 14 + (num - 1) / 8;
316 if (num >= NUM_VOP_FREE_BUCKETS)
323 /* Initialize the VOP free buckets. */
326 init_vop_buckets (void)
330 for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
331 gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
335 /* Add PTR to the appropriate VOP bucket. */
338 add_vop_to_freelist (voptype_p ptr)
340 int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
342 /* Too large, use the largest bucket so its not a complete throw away. */
344 bucket = NUM_VOP_FREE_BUCKETS - 1;
346 ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
347 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
351 /* These are the sizes of the operand memory buffer which gets allocated each
352 time more operands space is required. The final value is the amount that is
353 allocated every time after that. */
355 #define OP_SIZE_INIT 0
357 #define OP_SIZE_2 110
358 #define OP_SIZE_3 511
360 /* Initialize the operand cache routines. */
363 init_ssa_operands (void)
365 if (!n_initialized++)
367 build_defs = VEC_alloc (tree, heap, 5);
368 build_uses = VEC_alloc (tree, heap, 10);
369 build_vuses = VEC_alloc (tree, heap, 25);
370 build_vdefs = VEC_alloc (tree, heap, 25);
371 bitmap_obstack_initialize (&operands_bitmap_obstack);
372 build_loads = BITMAP_ALLOC (&operands_bitmap_obstack);
373 build_stores = BITMAP_ALLOC (&operands_bitmap_obstack);
374 scb_stack = VEC_alloc (scb_t, heap, 20);
377 gcc_assert (gimple_ssa_operands (cfun)->operand_memory == NULL);
378 gcc_assert (gimple_ssa_operands (cfun)->mpt_table == NULL);
379 gimple_ssa_operands (cfun)->operand_memory_index
380 = gimple_ssa_operands (cfun)->ssa_operand_mem_size;
381 gimple_ssa_operands (cfun)->ops_active = true;
382 memset (&clobber_stats, 0, sizeof (clobber_stats));
384 gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
388 /* Dispose of anything required by the operand routines. */
391 fini_ssa_operands (void)
393 struct ssa_operand_memory_d *ptr;
397 if (!--n_initialized)
399 VEC_free (tree, heap, build_defs);
400 VEC_free (tree, heap, build_uses);
401 VEC_free (tree, heap, build_vdefs);
402 VEC_free (tree, heap, build_vuses);
403 BITMAP_FREE (build_loads);
404 BITMAP_FREE (build_stores);
406 /* The change buffer stack had better be empty. */
407 gcc_assert (VEC_length (scb_t, scb_stack) == 0);
408 VEC_free (scb_t, heap, scb_stack);
412 gimple_ssa_operands (cfun)->free_defs = NULL;
413 gimple_ssa_operands (cfun)->free_uses = NULL;
415 while ((ptr = gimple_ssa_operands (cfun)->operand_memory) != NULL)
417 gimple_ssa_operands (cfun)->operand_memory
418 = gimple_ssa_operands (cfun)->operand_memory->next;
423 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
427 BITMAP_FREE (MPT_SYMBOLS (mpt));
430 VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
432 gimple_ssa_operands (cfun)->ops_active = false;
435 bitmap_obstack_release (&operands_bitmap_obstack);
436 if (dump_file && (dump_flags & TDF_STATS))
438 fprintf (dump_file, "Original clobbered vars: %d\n",
439 clobber_stats.clobbered_vars);
440 fprintf (dump_file, "Static write clobbers avoided: %d\n",
441 clobber_stats.static_write_clobbers_avoided);
442 fprintf (dump_file, "Static read clobbers avoided: %d\n",
443 clobber_stats.static_read_clobbers_avoided);
444 fprintf (dump_file, "Unescapable clobbers avoided: %d\n",
445 clobber_stats.unescapable_clobbers_avoided);
446 fprintf (dump_file, "Original read-only clobbers: %d\n",
447 clobber_stats.readonly_clobbers);
448 fprintf (dump_file, "Static read-only clobbers avoided: %d\n",
449 clobber_stats.static_readonly_clobbers_avoided);
454 /* Return memory for operands of SIZE chunks. */
457 ssa_operand_alloc (unsigned size)
461 if (gimple_ssa_operands (cfun)->operand_memory_index + size
462 >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
464 struct ssa_operand_memory_d *ptr;
466 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size == OP_SIZE_INIT)
467 gimple_ssa_operands (cfun)->ssa_operand_mem_size
468 = OP_SIZE_1 * sizeof (struct voptype_d);
470 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size
471 == OP_SIZE_1 * sizeof (struct voptype_d))
472 gimple_ssa_operands (cfun)->ssa_operand_mem_size
473 = OP_SIZE_2 * sizeof (struct voptype_d);
475 gimple_ssa_operands (cfun)->ssa_operand_mem_size
476 = OP_SIZE_3 * sizeof (struct voptype_d);
478 /* Go right to the maximum size if the request is too large. */
479 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
480 gimple_ssa_operands (cfun)->ssa_operand_mem_size
481 = OP_SIZE_3 * sizeof (struct voptype_d);
483 /* Fail if there is not enough space. If there are this many operands
484 required, first make sure there isn't a different problem causing this
485 many operands. If the decision is that this is OK, then we can
486 specially allocate a buffer just for this request. */
487 gcc_assert (size <= gimple_ssa_operands (cfun)->ssa_operand_mem_size);
489 ptr = (struct ssa_operand_memory_d *)
490 ggc_alloc (sizeof (struct ssa_operand_memory_d)
491 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
492 ptr->next = gimple_ssa_operands (cfun)->operand_memory;
493 gimple_ssa_operands (cfun)->operand_memory = ptr;
494 gimple_ssa_operands (cfun)->operand_memory_index = 0;
496 ptr = &(gimple_ssa_operands (cfun)->operand_memory
497 ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
498 gimple_ssa_operands (cfun)->operand_memory_index += size;
503 /* Allocate a DEF operand. */
505 static inline struct def_optype_d *
508 struct def_optype_d *ret;
509 if (gimple_ssa_operands (cfun)->free_defs)
511 ret = gimple_ssa_operands (cfun)->free_defs;
512 gimple_ssa_operands (cfun)->free_defs
513 = gimple_ssa_operands (cfun)->free_defs->next;
516 ret = (struct def_optype_d *)
517 ssa_operand_alloc (sizeof (struct def_optype_d));
522 /* Allocate a USE operand. */
524 static inline struct use_optype_d *
527 struct use_optype_d *ret;
528 if (gimple_ssa_operands (cfun)->free_uses)
530 ret = gimple_ssa_operands (cfun)->free_uses;
531 gimple_ssa_operands (cfun)->free_uses
532 = gimple_ssa_operands (cfun)->free_uses->next;
535 ret = (struct use_optype_d *)
536 ssa_operand_alloc (sizeof (struct use_optype_d));
541 /* Allocate a vop with NUM elements. */
543 static inline struct voptype_d *
546 struct voptype_d *ret = NULL;
549 int bucket = vop_free_bucket_index (num);
552 /* If there is a free operand, use it. */
553 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
555 ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
556 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] =
557 gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
560 alloc_size = vop_free_bucket_size(bucket);
566 ret = (struct voptype_d *)ssa_operand_alloc (
567 sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
569 VUSE_VECT_NUM_ELEM (ret->usev) = num;
574 /* This routine makes sure that PTR is in an immediate use list, and makes
575 sure the stmt pointer is set to the current stmt. */
578 set_virtual_use_link (use_operand_p ptr, tree stmt)
580 /* fold_stmt may have changed the stmt pointers. */
581 if (ptr->stmt != stmt)
584 /* If this use isn't in a list, add it to the correct list. */
586 link_imm_use (ptr, *(ptr->use));
590 /* Adds OP to the list of defs after LAST. */
592 static inline def_optype_p
593 add_def_op (tree *op, def_optype_p last)
595 def_optype_p new_def;
597 new_def = alloc_def ();
598 DEF_OP_PTR (new_def) = op;
599 last->next = new_def;
600 new_def->next = NULL;
605 /* Adds OP to the list of uses of statement STMT after LAST. */
607 static inline use_optype_p
608 add_use_op (tree stmt, tree *op, use_optype_p last)
610 use_optype_p new_use;
612 new_use = alloc_use ();
613 USE_OP_PTR (new_use)->use = op;
614 link_imm_use_stmt (USE_OP_PTR (new_use), *op, stmt);
615 last->next = new_use;
616 new_use->next = NULL;
621 /* Return a virtual op pointer with NUM elements which are all initialized to OP
622 and are linked into the immediate uses for STMT. The new vop is appended
625 static inline voptype_p
626 add_vop (tree stmt, tree op, int num, voptype_p prev)
631 new_vop = alloc_vop (num);
632 for (x = 0; x < num; x++)
634 VUSE_OP_PTR (new_vop, x)->prev = NULL;
635 SET_VUSE_OP (new_vop, x, op);
636 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
637 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
638 new_vop->usev.uses[x].use_var, stmt);
642 prev->next = new_vop;
643 new_vop->next = NULL;
648 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
649 LAST to the new element. */
651 static inline voptype_p
652 add_vuse_op (tree stmt, tree op, int num, voptype_p last)
654 voptype_p new_vop = add_vop (stmt, op, num, last);
655 VDEF_RESULT (new_vop) = NULL_TREE;
660 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
661 LAST to the new element. */
663 static inline voptype_p
664 add_vdef_op (tree stmt, tree op, int num, voptype_p last)
666 voptype_p new_vop = add_vop (stmt, op, num, last);
667 VDEF_RESULT (new_vop) = op;
672 /* Takes elements from build_defs and turns them into def operands of STMT.
673 TODO -- Make build_defs VEC of tree *. */
676 finalize_ssa_defs (tree stmt)
679 struct def_optype_d new_list;
680 def_optype_p old_ops, last;
681 unsigned int num = VEC_length (tree, build_defs);
683 /* There should only be a single real definition per assignment. */
684 gcc_assert ((stmt && TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) || num <= 1);
686 new_list.next = NULL;
689 old_ops = DEF_OPS (stmt);
693 /* Check for the common case of 1 def that hasn't changed. */
694 if (old_ops && old_ops->next == NULL && num == 1
695 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
698 /* If there is anything in the old list, free it. */
701 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
702 gimple_ssa_operands (cfun)->free_defs = old_ops;
705 /* If there is anything remaining in the build_defs list, simply emit it. */
706 for ( ; new_i < num; new_i++)
707 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
709 /* Now set the stmt's operands. */
710 DEF_OPS (stmt) = new_list.next;
712 #ifdef ENABLE_CHECKING
716 for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
719 gcc_assert (x == num);
725 /* Takes elements from build_uses and turns them into use operands of STMT.
726 TODO -- Make build_uses VEC of tree *. */
729 finalize_ssa_uses (tree stmt)
732 struct use_optype_d new_list;
733 use_optype_p old_ops, ptr, last;
735 #ifdef ENABLE_CHECKING
738 unsigned num = VEC_length (tree, build_uses);
740 /* If the pointer to the operand is the statement itself, something is
741 wrong. It means that we are pointing to a local variable (the
742 initial call to update_stmt_operands does not pass a pointer to a
744 for (x = 0; x < num; x++)
745 gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
749 new_list.next = NULL;
752 old_ops = USE_OPS (stmt);
754 /* If there is anything in the old list, free it. */
757 for (ptr = old_ops; ptr; ptr = ptr->next)
758 delink_imm_use (USE_OP_PTR (ptr));
759 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
760 gimple_ssa_operands (cfun)->free_uses = old_ops;
763 /* Now create nodes for all the new nodes. */
764 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
765 last = add_use_op (stmt,
766 (tree *) VEC_index (tree, build_uses, new_i),
769 /* Now set the stmt's operands. */
770 USE_OPS (stmt) = new_list.next;
772 #ifdef ENABLE_CHECKING
775 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
778 gcc_assert (x == VEC_length (tree, build_uses));
784 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
785 STMT. FIXME, for now VDEF operators should have a single operand
789 finalize_ssa_vdefs (tree stmt)
792 struct voptype_d new_list;
793 voptype_p old_ops, ptr, last;
794 stmt_ann_t ann = stmt_ann (stmt);
796 /* Set the symbols referenced by STMT. */
797 if (!bitmap_empty_p (build_stores))
799 if (ann->operands.stores == NULL)
800 ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
802 bitmap_copy (ann->operands.stores, build_stores);
805 BITMAP_FREE (ann->operands.stores);
807 /* If aliases have not been computed, do not instantiate a virtual
808 operator on STMT. Initially, we only compute the SSA form on
809 GIMPLE registers. The virtual SSA form is only computed after
810 alias analysis, so virtual operators will remain unrenamed and
811 the verifier will complain. However, alias analysis needs to
812 access symbol load/store information, so we need to compute
814 if (!gimple_aliases_computed_p (cfun))
817 new_list.next = NULL;
820 old_ops = VDEF_OPS (stmt);
822 while (old_ops && new_i < VEC_length (tree, build_vdefs))
824 tree op = VEC_index (tree, build_vdefs, new_i);
825 unsigned new_uid = get_name_decl (op);
826 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
828 /* FIXME, for now each VDEF operator should have at most one
829 operand in their RHS. */
830 gcc_assert (VDEF_NUM (old_ops) == 1);
832 if (old_uid == new_uid)
834 /* If the symbols are the same, reuse the existing operand. */
835 last->next = old_ops;
837 old_ops = old_ops->next;
839 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
842 else if (old_uid < new_uid)
844 /* If old is less than new, old goes to the free list. */
846 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
847 next = old_ops->next;
848 add_vop_to_freelist (old_ops);
853 /* This is a new operand. */
854 last = add_vdef_op (stmt, op, 1, last);
859 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
860 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
861 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
863 /* If there is anything in the old list, free it. */
866 for (ptr = old_ops; ptr; ptr = last)
869 delink_imm_use (VDEF_OP_PTR (ptr, 0));
870 add_vop_to_freelist (ptr);
874 /* Now set STMT's operands. */
875 VDEF_OPS (stmt) = new_list.next;
877 #ifdef ENABLE_CHECKING
880 for (ptr = VDEF_OPS (stmt); ptr; ptr = ptr->next)
883 gcc_assert (x == VEC_length (tree, build_vdefs));
889 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
893 finalize_ssa_vuse_ops (tree stmt)
895 unsigned new_i, old_i;
896 voptype_p old_ops, last;
897 VEC(tree,heap) *new_ops;
900 /* Set the symbols referenced by STMT. */
901 ann = stmt_ann (stmt);
902 if (!bitmap_empty_p (build_loads))
904 if (ann->operands.loads == NULL)
905 ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
907 bitmap_copy (ann->operands.loads, build_loads);
910 BITMAP_FREE (ann->operands.loads);
912 /* If aliases have not been computed, do not instantiate a virtual
913 operator on STMT. Initially, we only compute the SSA form on
914 GIMPLE registers. The virtual SSA form is only computed after
915 alias analysis, so virtual operators will remain unrenamed and
916 the verifier will complain. However, alias analysis needs to
917 access symbol load/store information, so we need to compute
919 if (!gimple_aliases_computed_p (cfun))
922 /* STMT should have at most one VUSE operator. */
923 old_ops = VUSE_OPS (stmt);
924 gcc_assert (old_ops == NULL || old_ops->next == NULL);
929 && old_i < VUSE_NUM (old_ops)
930 && new_i < VEC_length (tree, build_vuses))
932 tree new_op = VEC_index (tree, build_vuses, new_i);
933 tree old_op = VUSE_OP (old_ops, old_i);
934 unsigned new_uid = get_name_decl (new_op);
935 unsigned old_uid = get_name_decl (old_op);
937 if (old_uid == new_uid)
939 /* If the symbols are the same, reuse the existing operand. */
940 VEC_safe_push (tree, heap, new_ops, old_op);
944 else if (old_uid < new_uid)
946 /* If OLD_UID is less than NEW_UID, the old operand has
947 disappeared, skip to the next old operand. */
952 /* This is a new operand. */
953 VEC_safe_push (tree, heap, new_ops, new_op);
958 /* If there is anything remaining in the build_vuses list, simply emit it. */
959 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
960 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
962 /* If there is anything in the old list, free it. */
965 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
966 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
967 add_vop_to_freelist (old_ops);
968 VUSE_OPS (stmt) = NULL;
971 /* If there are any operands, instantiate a VUSE operator for STMT. */
977 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
979 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
980 SET_USE (VUSE_OP_PTR (last, (int) i), op);
982 VUSE_OPS (stmt) = last;
983 VEC_free (tree, heap, new_ops);
986 #ifdef ENABLE_CHECKING
992 gcc_assert (VUSE_OPS (stmt)->next == NULL);
993 x = VUSE_NUM (VUSE_OPS (stmt));
998 gcc_assert (x == VEC_length (tree, build_vuses));
1003 /* Return a new VUSE operand vector for STMT. */
1006 finalize_ssa_vuses (tree stmt)
1008 unsigned num, num_vdefs;
1009 unsigned vuse_index;
1011 /* Remove superfluous VUSE operands. If the statement already has a
1012 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1013 needed because VDEFs imply a VUSE of the variable. For instance,
1014 suppose that variable 'a' is pointed-to by p and q:
1020 The VUSE <a_2> is superfluous because it is implied by the
1022 num = VEC_length (tree, build_vuses);
1023 num_vdefs = VEC_length (tree, build_vdefs);
1025 if (num > 0 && num_vdefs > 0)
1026 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1029 vuse = VEC_index (tree, build_vuses, vuse_index);
1030 if (TREE_CODE (vuse) != SSA_NAME)
1032 var_ann_t ann = var_ann (vuse);
1033 ann->in_vuse_list = 0;
1034 if (ann->in_vdef_list)
1036 VEC_ordered_remove (tree, build_vuses, vuse_index);
1043 finalize_ssa_vuse_ops (stmt);
1047 /* Clear the in_list bits and empty the build array for VDEFs and
1051 cleanup_build_arrays (void)
1056 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1057 if (TREE_CODE (t) != SSA_NAME)
1058 var_ann (t)->in_vdef_list = false;
1060 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1061 if (TREE_CODE (t) != SSA_NAME)
1062 var_ann (t)->in_vuse_list = false;
1064 VEC_truncate (tree, build_vdefs, 0);
1065 VEC_truncate (tree, build_vuses, 0);
1066 VEC_truncate (tree, build_defs, 0);
1067 VEC_truncate (tree, build_uses, 0);
1068 bitmap_clear (build_loads);
1069 bitmap_clear (build_stores);
1073 /* Finalize all the build vectors, fill the new ones into INFO. */
1076 finalize_ssa_stmt_operands (tree stmt)
1078 finalize_ssa_defs (stmt);
1079 finalize_ssa_uses (stmt);
1080 finalize_ssa_vdefs (stmt);
1081 finalize_ssa_vuses (stmt);
1082 cleanup_build_arrays ();
1086 /* Start the process of building up operands vectors in INFO. */
1089 start_ssa_stmt_operands (void)
1091 gcc_assert (VEC_length (tree, build_defs) == 0);
1092 gcc_assert (VEC_length (tree, build_uses) == 0);
1093 gcc_assert (VEC_length (tree, build_vuses) == 0);
1094 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1095 gcc_assert (bitmap_empty_p (build_loads));
1096 gcc_assert (bitmap_empty_p (build_stores));
1100 /* Add DEF_P to the list of pointers to operands. */
1103 append_def (tree *def_p)
1105 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1109 /* Add USE_P to the list of pointers to operands. */
1112 append_use (tree *use_p)
1114 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1118 /* Add VAR to the set of variables that require a VDEF operator. */
1121 append_vdef (tree var)
1125 if (TREE_CODE (var) != SSA_NAME)
1130 /* If VAR belongs to a memory partition, use it instead of VAR. */
1131 mpt = memory_partition (var);
1135 /* Don't allow duplicate entries. */
1136 ann = get_var_ann (var);
1137 if (ann->in_vdef_list)
1140 ann->in_vdef_list = true;
1144 sym = SSA_NAME_VAR (var);
1146 VEC_safe_push (tree, heap, build_vdefs, var);
1147 bitmap_set_bit (build_stores, DECL_UID (sym));
1151 /* Add VAR to the set of variables that require a VUSE operator. */
1154 append_vuse (tree var)
1158 if (TREE_CODE (var) != SSA_NAME)
1163 /* If VAR belongs to a memory partition, use it instead of VAR. */
1164 mpt = memory_partition (var);
1168 /* Don't allow duplicate entries. */
1169 ann = get_var_ann (var);
1170 if (ann->in_vuse_list || ann->in_vdef_list)
1173 ann->in_vuse_list = true;
1177 sym = SSA_NAME_VAR (var);
1179 VEC_safe_push (tree, heap, build_vuses, var);
1180 bitmap_set_bit (build_loads, DECL_UID (sym));
1184 /* REF is a tree that contains the entire pointer dereference
1185 expression, if available, or NULL otherwise. ALIAS is the variable
1186 we are asking if REF can access. OFFSET and SIZE come from the
1187 memory access expression that generated this virtual operand. */
1190 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1193 bool offsetgtz = offset > 0;
1194 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1195 tree base = ref ? get_base_address (ref) : NULL;
1197 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1198 using a call-clobbered memory tag. By definition, call-clobbered
1199 memory tags can always touch .GLOBAL_VAR. */
1200 if (alias == gimple_global_var (cfun))
1203 /* If ALIAS is an SFT, it can't be touched if the offset
1204 and size of the access is not overlapping with the SFT offset and
1205 size. This is only true if we are accessing through a pointer
1206 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1207 be accessing through a pointer to some substruct of the
1208 structure, and if we try to prune there, we will have the wrong
1209 offset, and get the wrong answer.
1210 i.e., we can't prune without more work if we have something like
1216 const char *byte_op;
1224 foo = &targetm.asm_out.aligned_op;
1227 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1228 terms of SFT_PARENT_VAR, that is where it is.
1229 However, the access through the foo pointer will be at offset 0. */
1231 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1233 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1234 && !overlap_subvar (offset, size, alias, NULL))
1236 #ifdef ACCESS_DEBUGGING
1237 fprintf (stderr, "Access to ");
1238 print_generic_expr (stderr, ref, 0);
1239 fprintf (stderr, " may not touch ");
1240 print_generic_expr (stderr, alias, 0);
1241 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1246 /* Without strict aliasing, it is impossible for a component access
1247 through a pointer to touch a random variable, unless that
1248 variable *is* a structure or a pointer.
1250 That is, given p->c, and some random global variable b,
1251 there is no legal way that p->c could be an access to b.
1253 Without strict aliasing on, we consider it legal to do something
1256 struct foos { int l; };
1258 static struct foos *getfoo(void);
1261 struct foos *f = getfoo();
1268 static struct foos *getfoo(void)
1269 { return (struct foos *)&foo; }
1271 (taken from 20000623-1.c)
1273 The docs also say/imply that access through union pointers
1274 is legal (but *not* if you take the address of the union member,
1275 i.e. the inverse), such that you can do
1285 U *pretmp = (U*)&rv;
1289 To implement this, we just punt on accesses through union
1293 && flag_strict_aliasing
1294 && TREE_CODE (ref) != INDIRECT_REF
1296 && (TREE_CODE (base) != INDIRECT_REF
1297 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1298 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1299 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1300 && !var_ann (alias)->is_heapvar
1301 /* When the struct has may_alias attached to it, we need not to
1303 && get_alias_set (base))
1305 #ifdef ACCESS_DEBUGGING
1306 fprintf (stderr, "Access to ");
1307 print_generic_expr (stderr, ref, 0);
1308 fprintf (stderr, " may not touch ");
1309 print_generic_expr (stderr, alias, 0);
1310 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1315 /* If the offset of the access is greater than the size of one of
1316 the possible aliases, it can't be touching that alias, because it
1317 would be past the end of the structure. */
1319 && flag_strict_aliasing
1320 && TREE_CODE (ref) != INDIRECT_REF
1322 && !POINTER_TYPE_P (TREE_TYPE (alias))
1324 && DECL_SIZE (alias)
1325 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1326 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1328 #ifdef ACCESS_DEBUGGING
1329 fprintf (stderr, "Access to ");
1330 print_generic_expr (stderr, ref, 0);
1331 fprintf (stderr, " may not touch ");
1332 print_generic_expr (stderr, alias, 0);
1333 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1342 /* Add VAR to the virtual operands array. FLAGS is as in
1343 get_expr_operands. FULL_REF is a tree that contains the entire
1344 pointer dereference expression, if available, or NULL otherwise.
1345 OFFSET and SIZE come from the memory access expression that
1346 generated this virtual operand. IS_CALL_SITE is true if the
1347 affected statement is a call site. */
1350 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1351 tree full_ref, HOST_WIDE_INT offset,
1352 HOST_WIDE_INT size, bool is_call_site)
1354 bitmap aliases = NULL;
1358 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1359 v_ann = var_ann (sym);
1361 /* Mark the statement as having memory operands. */
1362 s_ann->references_memory = true;
1364 /* Mark statements with volatile operands. Optimizers should back
1365 off from statements having volatile operands. */
1366 if (TREE_THIS_VOLATILE (sym) && s_ann)
1367 s_ann->has_volatile_ops = true;
1369 /* If the variable cannot be modified and this is a VDEF change
1370 it into a VUSE. This happens when read-only variables are marked
1371 call-clobbered and/or aliased to writable variables. So we only
1372 check that this only happens on non-specific stores.
1374 Note that if this is a specific store, i.e. associated with a
1375 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1376 into validation problems.
1378 This can happen when programs cast away const, leaving us with a
1379 store to read-only memory. If the statement is actually executed
1380 at runtime, then the program is ill formed. If the statement is
1381 not executed then all is well. At the very least, we cannot ICE. */
1382 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1385 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1386 virtual operands, unless the caller has specifically requested
1387 not to add virtual operands (used when adding operands inside an
1388 ADDR_EXPR expression). */
1389 if (flags & opf_no_vops)
1393 aliases = MTAG_ALIASES (var);
1395 if (aliases == NULL)
1397 if (s_ann && !gimple_aliases_computed_p (cfun))
1398 s_ann->has_volatile_ops = true;
1400 /* The variable is not aliased or it is an alias tag. */
1401 if (flags & opf_def)
1412 /* The variable is aliased. Add its aliases to the virtual
1414 gcc_assert (!bitmap_empty_p (aliases));
1416 if (flags & opf_def)
1418 bool none_added = true;
1419 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1421 al = referenced_var (i);
1422 if (!access_can_touch_variable (full_ref, al, offset, size))
1425 /* Call-clobbered tags may have non-call-clobbered
1426 symbols in their alias sets. Ignore them if we are
1427 adding VOPs for a call site. */
1428 if (is_call_site && !is_call_clobbered (al))
1435 /* If the variable is also an alias tag, add a virtual
1436 operand for it, otherwise we will miss representing
1437 references to the members of the variable's alias set.
1438 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1440 It is also necessary to add bare defs on clobbers for
1441 SMT's, so that bare SMT uses caused by pruning all the
1442 aliases will link up properly with calls. In order to
1443 keep the number of these bare defs we add down to the
1444 minimum necessary, we keep track of which SMT's were used
1445 alone in statement vdefs or VUSEs. */
1447 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1455 bool none_added = true;
1456 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1458 al = referenced_var (i);
1459 if (!access_can_touch_variable (full_ref, al, offset, size))
1462 /* Call-clobbered tags may have non-call-clobbered
1463 symbols in their alias sets. Ignore them if we are
1464 adding VOPs for a call site. */
1465 if (is_call_site && !is_call_clobbered (al))
1472 /* Even if no aliases have been added, we still need to
1473 establish def-use and use-def chains, lest
1474 transformations think that this is not a memory
1475 reference. For an example of this scenario, see
1476 testsuite/g++.dg/opt/cleanup1.C. */
1484 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1485 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1486 the statement's real operands, otherwise it is added to virtual
1490 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1495 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1498 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1499 v_ann = var_ann (sym);
1501 /* Mark statements with volatile operands. */
1502 if (TREE_THIS_VOLATILE (sym))
1503 s_ann->has_volatile_ops = true;
1505 if (is_gimple_reg (sym))
1507 /* The variable is a GIMPLE register. Add it to real operands. */
1508 if (flags & opf_def)
1514 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1518 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1519 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1521 STMT is the statement being processed, EXPR is the INDIRECT_REF
1524 FLAGS is as in get_expr_operands.
1526 FULL_REF contains the full pointer dereference expression, if we
1527 have it, or NULL otherwise.
1529 OFFSET and SIZE are the location of the access inside the
1530 dereferenced pointer, if known.
1532 RECURSE_ON_BASE should be set to true if we want to continue
1533 calling get_expr_operands on the base pointer, and false if
1534 something else will do it for us. */
1537 get_indirect_ref_operands (tree stmt, tree expr, int flags,
1539 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1540 bool recurse_on_base)
1542 tree *pptr = &TREE_OPERAND (expr, 0);
1544 stmt_ann_t s_ann = stmt_ann (stmt);
1546 s_ann->references_memory = true;
1547 if (s_ann && TREE_THIS_VOLATILE (expr))
1548 s_ann->has_volatile_ops = true;
1550 if (SSA_VAR_P (ptr))
1552 struct ptr_info_def *pi = NULL;
1554 /* If PTR has flow-sensitive points-to information, use it. */
1555 if (TREE_CODE (ptr) == SSA_NAME
1556 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1557 && pi->name_mem_tag)
1559 /* PTR has its own memory tag. Use it. */
1560 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1561 full_ref, offset, size, false);
1565 /* If PTR is not an SSA_NAME or it doesn't have a name
1566 tag, use its symbol memory tag. */
1569 /* If we are emitting debugging dumps, display a warning if
1570 PTR is an SSA_NAME with no flow-sensitive alias
1571 information. That means that we may need to compute
1574 && TREE_CODE (ptr) == SSA_NAME
1578 "NOTE: no flow-sensitive alias info for ");
1579 print_generic_expr (dump_file, ptr, dump_flags);
1580 fprintf (dump_file, " in ");
1581 print_generic_stmt (dump_file, stmt, dump_flags);
1584 if (TREE_CODE (ptr) == SSA_NAME)
1585 ptr = SSA_NAME_VAR (ptr);
1586 v_ann = var_ann (ptr);
1588 if (v_ann->symbol_mem_tag)
1589 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1590 full_ref, offset, size, false);
1592 /* Aliasing information is missing; mark statement as
1593 volatile so we won't optimize it out too actively. */
1595 && !gimple_aliases_computed_p (cfun)
1596 && (flags & opf_def))
1597 s_ann->has_volatile_ops = true;
1600 else if (TREE_CODE (ptr) == INTEGER_CST)
1602 /* If a constant is used as a pointer, we can't generate a real
1603 operand for it but we mark the statement volatile to prevent
1604 optimizations from messing things up. */
1606 s_ann->has_volatile_ops = true;
1611 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1615 /* If requested, add a USE operand for the base pointer. */
1616 if (recurse_on_base)
1617 get_expr_operands (stmt, pptr, opf_use);
1621 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1624 get_tmr_operands (tree stmt, tree expr, int flags)
1627 HOST_WIDE_INT offset, size, maxsize;
1629 stmt_ann_t s_ann = stmt_ann (stmt);
1631 /* This statement references memory. */
1632 s_ann->references_memory = 1;
1634 /* First record the real operands. */
1635 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1636 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1638 if (TMR_SYMBOL (expr))
1639 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1641 tag = TMR_TAG (expr);
1644 /* Something weird, so ensure that we will be careful. */
1645 s_ann->has_volatile_ops = true;
1651 get_expr_operands (stmt, &tag, flags);
1655 ref = get_ref_base_and_extent (tag, &offset, &size, &maxsize);
1656 gcc_assert (ref != NULL_TREE);
1657 svars = get_subvars_for_var (ref);
1658 for (sv = svars; sv; sv = sv->next)
1662 if (overlap_subvar (offset, maxsize, sv->var, &exact))
1663 add_stmt_operand (&sv->var, s_ann, flags);
1668 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1669 clobbered variables in the function. */
1672 add_call_clobber_ops (tree stmt, tree callee)
1676 stmt_ann_t s_ann = stmt_ann (stmt);
1677 bitmap not_read_b, not_written_b;
1679 /* Functions that are not const, pure or never return may clobber
1680 call-clobbered variables. */
1682 s_ann->makes_clobbering_call = true;
1684 /* If we created .GLOBAL_VAR earlier, just use it. */
1685 if (gimple_global_var (cfun))
1687 tree var = gimple_global_var (cfun);
1688 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1692 /* Get info for local and module level statics. There is a bit
1693 set for each static if the call being processed does not read
1694 or write that variable. */
1695 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1696 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1698 /* Add a VDEF operand for every call clobbered variable. */
1699 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1701 tree var = referenced_var_lookup (u);
1702 unsigned int escape_mask = var_ann (var)->escape_mask;
1703 tree real_var = var;
1707 /* Not read and not written are computed on regular vars, not
1708 subvars, so look at the parent var if this is an SFT. */
1709 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1710 real_var = SFT_PARENT_VAR (var);
1712 not_read = not_read_b
1713 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1716 not_written = not_written_b
1717 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1719 gcc_assert (!unmodifiable_var_p (var));
1721 clobber_stats.clobbered_vars++;
1723 /* See if this variable is really clobbered by this function. */
1725 /* Trivial case: Things escaping only to pure/const are not
1726 clobbered by non-pure-const, and only read by pure/const. */
1727 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1729 tree call = get_call_expr_in (stmt);
1730 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1732 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1733 clobber_stats.unescapable_clobbers_avoided++;
1738 clobber_stats.unescapable_clobbers_avoided++;
1745 clobber_stats.static_write_clobbers_avoided++;
1747 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1749 clobber_stats.static_read_clobbers_avoided++;
1752 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1757 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1761 add_call_read_ops (tree stmt, tree callee)
1765 stmt_ann_t s_ann = stmt_ann (stmt);
1768 /* if the function is not pure, it may reference memory. Add
1769 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1770 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1771 if (gimple_global_var (cfun))
1773 tree var = gimple_global_var (cfun);
1774 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1778 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1780 /* Add a VUSE for each call-clobbered variable. */
1781 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1783 tree var = referenced_var (u);
1784 tree real_var = var;
1787 clobber_stats.readonly_clobbers++;
1789 /* Not read and not written are computed on regular vars, not
1790 subvars, so look at the parent var if this is an SFT. */
1792 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1793 real_var = SFT_PARENT_VAR (var);
1795 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1800 clobber_stats.static_readonly_clobbers_avoided++;
1804 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1809 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1812 get_call_expr_operands (tree stmt, tree expr)
1814 int call_flags = call_expr_flags (expr);
1816 stmt_ann_t ann = stmt_ann (stmt);
1818 ann->references_memory = true;
1820 /* If aliases have been computed already, add VDEF or VUSE
1821 operands for all the symbols that have been found to be
1823 if (gimple_aliases_computed_p (cfun)
1824 && !(call_flags & ECF_NOVOPS))
1826 /* A 'pure' or a 'const' function never call-clobbers anything.
1827 A 'noreturn' function might, but since we don't return anyway
1828 there is no point in recording that. */
1829 if (TREE_SIDE_EFFECTS (expr)
1830 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1831 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1832 else if (!(call_flags & ECF_CONST))
1833 add_call_read_ops (stmt, get_callee_fndecl (expr));
1836 /* Find uses in the called function. */
1837 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1838 nargs = call_expr_nargs (expr);
1839 for (i = 0; i < nargs; i++)
1840 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1842 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1846 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1849 get_asm_expr_operands (tree stmt)
1853 const char **oconstraints;
1854 const char *constraint;
1855 bool allows_mem, allows_reg, is_inout;
1858 s_ann = stmt_ann (stmt);
1859 noutputs = list_length (ASM_OUTPUTS (stmt));
1860 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1862 /* Gather all output operands. */
1863 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1865 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1866 oconstraints[i] = constraint;
1867 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1868 &allows_reg, &is_inout);
1870 /* This should have been split in gimplify_asm_expr. */
1871 gcc_assert (!allows_reg || !is_inout);
1873 /* Memory operands are addressable. Note that STMT needs the
1874 address of this operand. */
1875 if (!allows_reg && allows_mem)
1877 tree t = get_base_address (TREE_VALUE (link));
1878 if (t && DECL_P (t) && s_ann)
1879 add_to_addressable_set (t, &s_ann->addresses_taken);
1882 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1885 /* Gather all input operands. */
1886 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1888 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1889 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1890 &allows_mem, &allows_reg);
1892 /* Memory operands are addressable. Note that STMT needs the
1893 address of this operand. */
1894 if (!allows_reg && allows_mem)
1896 tree t = get_base_address (TREE_VALUE (link));
1897 if (t && DECL_P (t) && s_ann)
1898 add_to_addressable_set (t, &s_ann->addresses_taken);
1901 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1904 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1905 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1906 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1911 s_ann->references_memory = true;
1913 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1915 tree var = referenced_var (i);
1916 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1919 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1921 tree var = referenced_var (i);
1923 /* Subvars are explicitly represented in this list, so we
1924 don't need the original to be added to the clobber ops,
1925 but the original *will* be in this list because we keep
1926 the addressability of the original variable up-to-date
1927 to avoid confusing the back-end. */
1928 if (var_can_have_subvars (var)
1929 && get_subvars_for_var (var) != NULL)
1932 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1939 /* Scan operands for the assignment expression EXPR in statement STMT. */
1942 get_modify_stmt_operands (tree stmt, tree expr)
1944 /* First get operands from the RHS. */
1945 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
1947 /* For the LHS, use a regular definition (opf_def) for GIMPLE
1948 registers. If the LHS is a store to memory, we will need
1949 a preserving definition (VDEF).
1951 Preserving definitions are those that modify a part of an
1952 aggregate object for which no subvars have been computed (or the
1953 reference does not correspond exactly to one of them). Stores
1954 through a pointer are also represented with VDEF operators.
1956 We used to distinguish between preserving and killing definitions.
1957 We always emit preserving definitions now. */
1958 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
1962 /* Recursively scan the expression pointed to by EXPR_P in statement
1963 STMT. FLAGS is one of the OPF_* constants modifying how to
1964 interpret the operands found. */
1967 get_expr_operands (tree stmt, tree *expr_p, int flags)
1969 enum tree_code code;
1970 enum tree_code_class codeclass;
1971 tree expr = *expr_p;
1972 stmt_ann_t s_ann = stmt_ann (stmt);
1977 code = TREE_CODE (expr);
1978 codeclass = TREE_CODE_CLASS (code);
1983 /* Taking the address of a variable does not represent a
1984 reference to it, but the fact that the statement takes its
1985 address will be of interest to some passes (e.g. alias
1987 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
1989 /* If the address is invariant, there may be no interesting
1990 variable references inside. */
1991 if (is_gimple_min_invariant (expr))
1994 /* Otherwise, there may be variables referenced inside but there
1995 should be no VUSEs created, since the referenced objects are
1996 not really accessed. The only operands that we should find
1997 here are ARRAY_REF indices which will always be real operands
1998 (GIMPLE does not allow non-registers as array indices). */
1999 flags |= opf_no_vops;
2000 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2004 case STRUCT_FIELD_TAG:
2005 case SYMBOL_MEMORY_TAG:
2006 case NAME_MEMORY_TAG:
2007 add_stmt_operand (expr_p, s_ann, flags);
2016 /* Add the subvars for a variable, if it has subvars, to DEFS
2017 or USES. Otherwise, add the variable itself. Whether it
2018 goes to USES or DEFS depends on the operand flags. */
2019 if (var_can_have_subvars (expr)
2020 && (svars = get_subvars_for_var (expr)))
2023 for (sv = svars; sv; sv = sv->next)
2024 add_stmt_operand (&sv->var, s_ann, flags);
2027 add_stmt_operand (expr_p, s_ann, flags);
2032 case MISALIGNED_INDIRECT_REF:
2033 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2036 case ALIGN_INDIRECT_REF:
2038 get_indirect_ref_operands (stmt, expr, flags, NULL_TREE, 0, -1, true);
2041 case TARGET_MEM_REF:
2042 get_tmr_operands (stmt, expr, flags);
2046 case ARRAY_RANGE_REF:
2052 HOST_WIDE_INT offset, size, maxsize;
2055 /* This component reference becomes an access to all of the
2056 subvariables it can touch, if we can determine that, but
2057 *NOT* the real one. If we can't determine which fields we
2058 could touch, the recursion will eventually get to a
2059 variable and add *all* of its subvars, or whatever is the
2060 minimum correct subset. */
2061 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2062 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2065 subvar_t svars = get_subvars_for_var (ref);
2067 for (sv = svars; sv; sv = sv->next)
2071 if (overlap_subvar (offset, maxsize, sv->var, &exact))
2073 int subvar_flags = flags;
2075 add_stmt_operand (&sv->var, s_ann, subvar_flags);
2080 flags |= opf_no_vops;
2082 else if (TREE_CODE (ref) == INDIRECT_REF)
2084 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2086 flags |= opf_no_vops;
2089 /* Even if we found subvars above we need to ensure to see
2090 immediate uses for d in s.a[d]. In case of s.a having
2091 a subvar or we would miss it otherwise. */
2092 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2094 if (code == COMPONENT_REF)
2096 if (s_ann && TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2097 s_ann->has_volatile_ops = true;
2098 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2100 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2102 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2103 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2104 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2110 case WITH_SIZE_EXPR:
2111 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2112 and an rvalue reference to its second argument. */
2113 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2114 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2118 get_call_expr_operands (stmt, expr);
2123 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2124 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2125 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2128 case GIMPLE_MODIFY_STMT:
2129 get_modify_stmt_operands (stmt, expr);
2134 /* General aggregate CONSTRUCTORs have been decomposed, but they
2135 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2136 constructor_elt *ce;
2137 unsigned HOST_WIDE_INT idx;
2140 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2142 get_expr_operands (stmt, &ce->value, opf_use);
2148 case TRUTH_NOT_EXPR:
2149 case VIEW_CONVERT_EXPR:
2151 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2154 case TRUTH_AND_EXPR:
2156 case TRUTH_XOR_EXPR:
2162 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2163 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2168 case REALIGN_LOAD_EXPR:
2170 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2171 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2172 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2176 case CHANGE_DYNAMIC_TYPE_EXPR:
2177 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2195 /* Expressions that make no memory references. */
2199 if (codeclass == tcc_unary)
2201 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2203 if (codeclass == tcc_constant || codeclass == tcc_type)
2207 /* If we get here, something has gone wrong. */
2208 #ifdef ENABLE_CHECKING
2209 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2211 fputs ("\n", stderr);
2217 /* Parse STMT looking for operands. When finished, the various
2218 build_* operand vectors will have potential operands in them. */
2221 parse_ssa_operands (tree stmt)
2223 enum tree_code code;
2225 code = TREE_CODE (stmt);
2228 case GIMPLE_MODIFY_STMT:
2229 get_modify_stmt_operands (stmt, stmt);
2233 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2237 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2241 get_asm_expr_operands (stmt);
2245 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2249 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2253 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2257 case CASE_LABEL_EXPR:
2258 case TRY_CATCH_EXPR:
2259 case TRY_FINALLY_EXPR:
2260 case EH_FILTER_EXPR:
2263 /* These nodes contain no variable references. */
2267 /* Notice that if get_expr_operands tries to use &STMT as the
2268 operand pointer (which may only happen for USE operands), we
2269 will fail in add_stmt_operand. This default will handle
2270 statements like empty statements, or CALL_EXPRs that may
2271 appear on the RHS of a statement or as statements themselves. */
2272 get_expr_operands (stmt, &stmt, opf_use);
2278 /* Create an operands cache for STMT. */
2281 build_ssa_operands (tree stmt)
2283 stmt_ann_t ann = get_stmt_ann (stmt);
2285 /* Initially assume that the statement has no volatile operands and
2286 makes no memory references. */
2287 ann->has_volatile_ops = false;
2288 ann->references_memory = false;
2289 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2290 if (ann->addresses_taken)
2291 bitmap_clear (ann->addresses_taken);
2293 start_ssa_stmt_operands ();
2294 parse_ssa_operands (stmt);
2295 operand_build_sort_virtual (build_vuses);
2296 operand_build_sort_virtual (build_vdefs);
2297 finalize_ssa_stmt_operands (stmt);
2299 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2300 ann->addresses_taken = NULL;
2301 /* For added safety, assume that statements with volatile operands
2302 also reference memory. */
2303 if (ann->has_volatile_ops)
2304 ann->references_memory = true;
2308 /* Free any operands vectors in OPS. */
2311 free_ssa_operands (stmt_operands_p ops)
2313 ops->def_ops = NULL;
2314 ops->use_ops = NULL;
2315 ops->vdef_ops = NULL;
2316 ops->vuse_ops = NULL;
2317 BITMAP_FREE (ops->loads);
2318 BITMAP_FREE (ops->stores);
2322 /* Get the operands of statement STMT. */
2325 update_stmt_operands (tree stmt)
2327 stmt_ann_t ann = get_stmt_ann (stmt);
2329 /* If update_stmt_operands is called before SSA is initialized, do
2331 if (!ssa_operands_active ())
2334 /* The optimizers cannot handle statements that are nothing but a
2335 _DECL. This indicates a bug in the gimplifier. */
2336 gcc_assert (!SSA_VAR_P (stmt));
2338 timevar_push (TV_TREE_OPS);
2340 gcc_assert (ann->modified);
2341 build_ssa_operands (stmt);
2344 timevar_pop (TV_TREE_OPS);
2348 /* Copies virtual operands from SRC to DST. */
2351 copy_virtual_operands (tree dest, tree src)
2354 voptype_p src_vuses, dest_vuses;
2355 voptype_p src_vdefs, dest_vdefs;
2356 struct voptype_d vuse;
2357 struct voptype_d vdef;
2358 stmt_ann_t dest_ann;
2360 VDEF_OPS (dest) = NULL;
2361 VUSE_OPS (dest) = NULL;
2363 dest_ann = get_stmt_ann (dest);
2364 BITMAP_FREE (dest_ann->operands.loads);
2365 BITMAP_FREE (dest_ann->operands.stores);
2367 if (LOADED_SYMS (src))
2369 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2370 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2373 if (STORED_SYMS (src))
2375 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2376 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2379 /* Copy all the VUSE operators and corresponding operands. */
2381 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2383 n = VUSE_NUM (src_vuses);
2384 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2385 for (i = 0; i < n; i++)
2386 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2388 if (VUSE_OPS (dest) == NULL)
2389 VUSE_OPS (dest) = vuse.next;
2392 /* Copy all the VDEF operators and corresponding operands. */
2394 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2396 n = VUSE_NUM (src_vdefs);
2397 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2398 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2399 for (i = 0; i < n; i++)
2400 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2402 if (VDEF_OPS (dest) == NULL)
2403 VDEF_OPS (dest) = vdef.next;
2408 /* Specifically for use in DOM's expression analysis. Given a store, we
2409 create an artificial stmt which looks like a load from the store, this can
2410 be used to eliminate redundant loads. OLD_OPS are the operands from the
2411 store stmt, and NEW_STMT is the new load which represents a load of the
2415 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2419 use_operand_p use_p;
2422 get_stmt_ann (new_stmt);
2424 /* Process NEW_STMT looking for operands. */
2425 start_ssa_stmt_operands ();
2426 parse_ssa_operands (new_stmt);
2428 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2429 if (TREE_CODE (op) != SSA_NAME)
2430 var_ann (op)->in_vuse_list = false;
2432 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2433 if (TREE_CODE (op) != SSA_NAME)
2434 var_ann (op)->in_vdef_list = false;
2436 /* Remove any virtual operands that were found. */
2437 VEC_truncate (tree, build_vdefs, 0);
2438 VEC_truncate (tree, build_vuses, 0);
2440 /* For each VDEF on the original statement, we want to create a
2441 VUSE of the VDEF result operand on the new statement. */
2442 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2445 finalize_ssa_stmt_operands (new_stmt);
2447 /* All uses in this fake stmt must not be in the immediate use lists. */
2448 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2449 delink_imm_use (use_p);
2453 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2454 to test the validity of the swap operation. */
2457 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2463 /* If the operand cache is active, attempt to preserve the relative
2464 positions of these two operands in their respective immediate use
2466 if (ssa_operands_active () && op0 != op1)
2468 use_optype_p use0, use1, ptr;
2471 /* Find the 2 operands in the cache, if they are there. */
2472 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2473 if (USE_OP_PTR (ptr)->use == exp0)
2479 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2480 if (USE_OP_PTR (ptr)->use == exp1)
2486 /* If both uses don't have operand entries, there isn't much we can do
2487 at this point. Presumably we don't need to worry about it. */
2490 tree *tmp = USE_OP_PTR (use1)->use;
2491 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2492 USE_OP_PTR (use0)->use = tmp;
2496 /* Now swap the data. */
2502 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2503 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2504 a single variable whose address has been taken or any other valid
2505 GIMPLE memory reference (structure reference, array, etc). If the
2506 base address of REF is a decl that has sub-variables, also add all
2507 of its sub-variables. */
2510 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2515 gcc_assert (addresses_taken);
2517 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2518 as the only thing we take the address of. If VAR is a structure,
2519 taking the address of a field means that the whole structure may
2520 be referenced using pointer arithmetic. See PR 21407 and the
2521 ensuing mailing list discussion. */
2522 var = get_base_address (ref);
2523 if (var && SSA_VAR_P (var))
2525 if (*addresses_taken == NULL)
2526 *addresses_taken = BITMAP_GGC_ALLOC ();
2528 if (var_can_have_subvars (var)
2529 && (svars = get_subvars_for_var (var)))
2532 for (sv = svars; sv; sv = sv->next)
2534 bitmap_set_bit (*addresses_taken, DECL_UID (sv->var));
2535 TREE_ADDRESSABLE (sv->var) = 1;
2540 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2541 TREE_ADDRESSABLE (var) = 1;
2547 /* Scan the immediate_use list for VAR making sure its linked properly.
2548 Return TRUE if there is a problem and emit an error message to F. */
2551 verify_imm_links (FILE *f, tree var)
2553 use_operand_p ptr, prev, list;
2556 gcc_assert (TREE_CODE (var) == SSA_NAME);
2558 list = &(SSA_NAME_IMM_USE_NODE (var));
2559 gcc_assert (list->use == NULL);
2561 if (list->prev == NULL)
2563 gcc_assert (list->next == NULL);
2569 for (ptr = list->next; ptr != list; )
2571 if (prev != ptr->prev)
2574 if (ptr->use == NULL)
2575 goto error; /* 2 roots, or SAFE guard node. */
2576 else if (*(ptr->use) != var)
2582 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2584 if (count++ > 50000000)
2588 /* Verify list in the other direction. */
2590 for (ptr = list->prev; ptr != list; )
2592 if (prev != ptr->next)
2606 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2608 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2609 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2611 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2613 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2619 /* Dump all the immediate uses to FILE. */
2622 dump_immediate_uses_for (FILE *file, tree var)
2624 imm_use_iterator iter;
2625 use_operand_p use_p;
2627 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2629 print_generic_expr (file, var, TDF_SLIM);
2630 fprintf (file, " : -->");
2631 if (has_zero_uses (var))
2632 fprintf (file, " no uses.\n");
2634 if (has_single_use (var))
2635 fprintf (file, " single use.\n");
2637 fprintf (file, "%d uses.\n", num_imm_uses (var));
2639 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2641 if (use_p->stmt == NULL && use_p->use == NULL)
2642 fprintf (file, "***end of stmt iterator marker***\n");
2644 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2645 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2647 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2649 fprintf(file, "\n");
2653 /* Dump all the immediate uses to FILE. */
2656 dump_immediate_uses (FILE *file)
2661 fprintf (file, "Immediate_uses: \n\n");
2662 for (x = 1; x < num_ssa_names; x++)
2667 dump_immediate_uses_for (file, var);
2672 /* Dump def-use edges on stderr. */
2675 debug_immediate_uses (void)
2677 dump_immediate_uses (stderr);
2681 /* Dump def-use edges on stderr. */
2684 debug_immediate_uses_for (tree var)
2686 dump_immediate_uses_for (stderr, var);
2690 /* Create a new change buffer for the statement pointed by STMT_P and
2691 push the buffer into SCB_STACK. Each change buffer
2692 records state information needed to determine what changed in the
2693 statement. Mainly, this keeps track of symbols that may need to be
2694 put into SSA form, SSA name replacements and other information
2695 needed to keep the SSA form up to date. */
2698 push_stmt_changes (tree *stmt_p)
2705 /* It makes no sense to keep track of PHI nodes. */
2706 if (TREE_CODE (stmt) == PHI_NODE)
2709 buf = XNEW (struct scb_d);
2710 memset (buf, 0, sizeof *buf);
2712 buf->stmt_p = stmt_p;
2714 if (stmt_references_memory_p (stmt))
2719 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2721 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2722 if (buf->loads == NULL)
2723 buf->loads = BITMAP_ALLOC (NULL);
2724 bitmap_set_bit (buf->loads, DECL_UID (sym));
2727 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2729 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2730 if (buf->stores == NULL)
2731 buf->stores = BITMAP_ALLOC (NULL);
2732 bitmap_set_bit (buf->stores, DECL_UID (sym));
2736 VEC_safe_push (scb_t, heap, scb_stack, buf);
2740 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2741 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2744 mark_difference_for_renaming (bitmap s1, bitmap s2)
2746 if (s1 == NULL && s2 == NULL)
2749 if (s1 && s2 == NULL)
2750 mark_set_for_renaming (s1);
2751 else if (s1 == NULL && s2)
2752 mark_set_for_renaming (s2);
2753 else if (!bitmap_equal_p (s1, s2))
2755 bitmap t1 = BITMAP_ALLOC (NULL);
2756 bitmap t2 = BITMAP_ALLOC (NULL);
2758 bitmap_and_compl (t1, s1, s2);
2759 bitmap_and_compl (t2, s2, s1);
2760 bitmap_ior_into (t1, t2);
2761 mark_set_for_renaming (t1);
2769 /* Pop the top SCB from SCB_STACK and act on the differences between
2770 what was recorded by push_stmt_changes and the current state of
2774 pop_stmt_changes (tree *stmt_p)
2778 bitmap loads, stores;
2783 /* It makes no sense to keep track of PHI nodes. */
2784 if (TREE_CODE (stmt) == PHI_NODE)
2787 buf = VEC_pop (scb_t, scb_stack);
2788 gcc_assert (stmt_p == buf->stmt_p);
2790 /* Force an operand re-scan on the statement and mark any newly
2791 exposed variables. */
2794 /* Determine whether any memory symbols need to be renamed. If the
2795 sets of loads and stores are different after the statement is
2796 modified, then the affected symbols need to be renamed.
2798 Note that it may be possible for the statement to not reference
2799 memory anymore, but we still need to act on the differences in
2800 the sets of symbols. */
2801 loads = stores = NULL;
2802 if (stmt_references_memory_p (stmt))
2807 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2809 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2811 loads = BITMAP_ALLOC (NULL);
2812 bitmap_set_bit (loads, DECL_UID (sym));
2815 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2817 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2819 stores = BITMAP_ALLOC (NULL);
2820 bitmap_set_bit (stores, DECL_UID (sym));
2824 /* If LOADS is different from BUF->LOADS, the affected
2825 symbols need to be marked for renaming. */
2826 mark_difference_for_renaming (loads, buf->loads);
2828 /* Similarly for STORES and BUF->STORES. */
2829 mark_difference_for_renaming (stores, buf->stores);
2831 /* Mark all the naked GIMPLE register operands for renaming. */
2832 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2834 mark_sym_for_renaming (op);
2836 /* FIXME, need to add more finalizers here. Cleanup EH info,
2837 recompute invariants for address expressions, add
2838 SSA replacement mappings, etc. For instance, given
2839 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2842 # SMT.4_20 = VDEF <SMT.4_16>
2845 So, the VDEF will disappear, but instead of marking SMT.4 for
2846 renaming it would be far more efficient to establish a
2847 replacement mapping that would replace every reference of
2848 SMT.4_20 with SMT.4_16. */
2850 /* Free memory used by the buffer. */
2851 BITMAP_FREE (buf->loads);
2852 BITMAP_FREE (buf->stores);
2853 BITMAP_FREE (loads);
2854 BITMAP_FREE (stores);
2860 /* Discard the topmost change buffer from SCB_STACK. This is useful
2861 when the caller realized that it did not actually modified the
2862 statement. It avoids the expensive operand re-scan. */
2865 discard_stmt_changes (tree *stmt_p)
2870 /* It makes no sense to keep track of PHI nodes. */
2872 if (TREE_CODE (stmt) == PHI_NODE)
2875 buf = VEC_pop (scb_t, scb_stack);
2876 gcc_assert (stmt_p == buf->stmt_p);
2878 /* Free memory used by the buffer. */
2879 BITMAP_FREE (buf->loads);
2880 BITMAP_FREE (buf->stores);
2886 /* Returns true if statement STMT may access memory. */
2889 stmt_references_memory_p (tree stmt)
2891 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
2894 return stmt_ann (stmt)->references_memory;