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 3, 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 COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
27 #include "diagnostic.h"
28 #include "tree-flow.h"
29 #include "tree-inline.h"
30 #include "tree-pass.h"
34 #include "langhooks.h"
35 #include "ipa-reference.h"
37 /* This file contains the code required to manage the operands cache of the
38 SSA optimizer. For every stmt, we maintain an operand cache in the stmt
39 annotation. This cache contains operands that will be of interest to
40 optimizers and other passes wishing to manipulate the IL.
42 The operand type are broken up into REAL and VIRTUAL operands. The real
43 operands are represented as pointers into the stmt's operand tree. Thus
44 any manipulation of the real operands will be reflected in the actual tree.
45 Virtual operands are represented solely in the cache, although the base
46 variable for the SSA_NAME may, or may not occur in the stmt's tree.
47 Manipulation of the virtual operands will not be reflected in the stmt tree.
49 The routines in this file are concerned with creating this operand cache
52 The operand tree is the parsed by the various get_* routines which look
53 through the stmt tree for the occurrence of operands which may be of
54 interest, and calls are made to the append_* routines whenever one is
55 found. There are 4 of these routines, each representing one of the
56 4 types of operands. Defs, Uses, Virtual Uses, and Virtual May Defs.
58 The append_* routines check for duplication, and simply keep a list of
59 unique objects for each operand type in the build_* extendable vectors.
61 Once the stmt tree is completely parsed, the finalize_ssa_operands()
62 routine is called, which proceeds to perform the finalization routine
63 on each of the 4 operand vectors which have been built up.
65 If the stmt had a previous operand cache, the finalization routines
66 attempt to match up the new operands with the old ones. If it's a perfect
67 match, the old vector is simply reused. If it isn't a perfect match, then
68 a new vector is created and the new operands are placed there. For
69 virtual operands, if the previous cache had SSA_NAME version of a
70 variable, and that same variable occurs in the same operands cache, then
71 the new cache vector will also get the same SSA_NAME.
73 i.e., if a stmt had a VUSE of 'a_5', and 'a' occurs in the new operand
74 vector for VUSE, then the new vector will also be modified such that
75 it contains 'a_5' rather than 'a'. */
78 /* Structure storing statistics on how many call clobbers we have, and
79 how many where avoided. */
83 /* Number of call-clobbered ops we attempt to add to calls in
84 add_call_clobbered_mem_symbols. */
85 unsigned int clobbered_vars;
87 /* Number of write-clobbers (VDEFs) avoided by using
88 not_written information. */
89 unsigned int static_write_clobbers_avoided;
91 /* Number of reads (VUSEs) avoided by using not_read information. */
92 unsigned int static_read_clobbers_avoided;
94 /* Number of write-clobbers avoided because the variable can't escape to
96 unsigned int unescapable_clobbers_avoided;
98 /* Number of read-only uses we attempt to add to calls in
99 add_call_read_mem_symbols. */
100 unsigned int readonly_clobbers;
102 /* Number of read-only uses we avoid using not_read information. */
103 unsigned int static_readonly_clobbers_avoided;
107 /* Flags to describe operand properties in helpers. */
109 /* By default, operands are loaded. */
112 /* Operand is the target of an assignment expression or a
113 call-clobbered variable. */
114 #define opf_def (1 << 0)
116 /* No virtual operands should be created in the expression. This is used
117 when traversing ADDR_EXPR nodes which have different semantics than
118 other expressions. Inside an ADDR_EXPR node, the only operands that we
119 need to consider are indices into arrays. For instance, &a.b[i] should
120 generate a USE of 'i' but it should not generate a VUSE for 'a' nor a
122 #define opf_no_vops (1 << 1)
124 /* Operand is an implicit reference. This is used to distinguish
125 explicit assignments in the form of GIMPLE_MODIFY_STMT from
126 clobbering sites like function calls or ASM_EXPRs. */
127 #define opf_implicit (1 << 2)
129 /* Array for building all the def operands. */
130 static VEC(tree,heap) *build_defs;
132 /* Array for building all the use operands. */
133 static VEC(tree,heap) *build_uses;
135 /* Set for building all the VDEF operands. */
136 static VEC(tree,heap) *build_vdefs;
138 /* Set for building all the VUSE operands. */
139 static VEC(tree,heap) *build_vuses;
141 /* Bitmap obstack for our datastructures that needs to survive across
142 compilations of multiple functions. */
143 static bitmap_obstack operands_bitmap_obstack;
145 /* Set for building all the loaded symbols. */
146 static bitmap build_loads;
148 /* Set for building all the stored symbols. */
149 static bitmap build_stores;
151 static void get_expr_operands (tree, tree *, int);
153 /* Number of functions with initialized ssa_operands. */
154 static int n_initialized = 0;
156 /* Statement change buffer. Data structure used to record state
157 information for statements. This is used to determine what needs
158 to be done in order to update the SSA web after a statement is
159 modified by a pass. If STMT is a statement that has just been
160 created, or needs to be folded via fold_stmt, or anything that
161 changes its physical structure then the pass should:
163 1- Call push_stmt_changes (&stmt) to record the current state of
164 STMT before any modifications are made.
166 2- Make all appropriate modifications to the statement.
168 3- Call pop_stmt_changes (&stmt) to find new symbols that
169 need to be put in SSA form, SSA name mappings for names that
170 have disappeared, recompute invariantness for address
171 expressions, cleanup EH information, etc.
173 If it is possible to determine that the statement was not modified,
174 instead of calling pop_stmt_changes it is quicker to call
175 discard_stmt_changes to avoid the expensive and unnecessary operand
176 re-scan and change comparison. */
180 /* Pointer to the statement being modified. */
183 /* If the statement references memory these are the sets of symbols
184 loaded and stored by the statement. */
189 typedef struct scb_d *scb_t;
191 DEF_VEC_ALLOC_P(scb_t,heap);
193 /* Stack of statement change buffers (SCB). Every call to
194 push_stmt_changes pushes a new buffer onto the stack. Calls to
195 pop_stmt_changes pop a buffer off of the stack and compute the set
196 of changes for the popped statement. */
197 static VEC(scb_t,heap) *scb_stack;
199 /* Return the DECL_UID of the base variable of T. */
201 static inline unsigned
202 get_name_decl (tree t)
204 if (TREE_CODE (t) != SSA_NAME)
207 return DECL_UID (SSA_NAME_VAR (t));
211 /* Comparison function for qsort used in operand_build_sort_virtual. */
214 operand_build_cmp (const void *p, const void *q)
216 tree e1 = *((const tree *)p);
217 tree e2 = *((const tree *)q);
220 u1 = get_name_decl (e1);
221 u2 = get_name_decl (e2);
223 /* We want to sort in ascending order. They can never be equal. */
224 #ifdef ENABLE_CHECKING
225 gcc_assert (u1 != u2);
227 return (u1 > u2 ? 1 : -1);
231 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
234 operand_build_sort_virtual (VEC(tree,heap) *list)
236 int num = VEC_length (tree, list);
243 if (get_name_decl (VEC_index (tree, list, 0))
244 > get_name_decl (VEC_index (tree, list, 1)))
246 /* Swap elements if in the wrong order. */
247 tree tmp = VEC_index (tree, list, 0);
248 VEC_replace (tree, list, 0, VEC_index (tree, list, 1));
249 VEC_replace (tree, list, 1, tmp);
254 /* There are 3 or more elements, call qsort. */
255 qsort (VEC_address (tree, list),
256 VEC_length (tree, list),
262 /* Return true if the SSA operands cache is active. */
265 ssa_operands_active (void)
267 return cfun->gimple_df && gimple_ssa_operands (cfun)->ops_active;
271 /* VOPs are of variable sized, so the free list maps "free buckets" to the
284 Any VOPs larger than this are simply added to the largest bucket when they
288 /* Return the number of operands used in bucket BUCKET. */
291 vop_free_bucket_size (int bucket)
293 #ifdef ENABLE_CHECKING
294 gcc_assert (bucket >= 0 && bucket < NUM_VOP_FREE_BUCKETS);
298 return (bucket - 13) * 8;
302 /* For a vop of NUM operands, return the bucket NUM belongs to. If NUM is
303 beyond the end of the bucket table, return -1. */
306 vop_free_bucket_index (int num)
308 gcc_assert (num > 0 && NUM_VOP_FREE_BUCKETS > 16);
310 /* Sizes 1 through 16 use buckets 0-15. */
313 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
314 num = 14 + (num - 1) / 8;
315 if (num >= NUM_VOP_FREE_BUCKETS)
322 /* Initialize the VOP free buckets. */
325 init_vop_buckets (void)
329 for (x = 0; x < NUM_VOP_FREE_BUCKETS; x++)
330 gimple_ssa_operands (cfun)->vop_free_buckets[x] = NULL;
334 /* Add PTR to the appropriate VOP bucket. */
337 add_vop_to_freelist (voptype_p ptr)
339 int bucket = vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr->usev));
341 /* Too large, use the largest bucket so its not a complete throw away. */
343 bucket = NUM_VOP_FREE_BUCKETS - 1;
345 ptr->next = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
346 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] = ptr;
350 /* These are the sizes of the operand memory buffer which gets allocated each
351 time more operands space is required. The final value is the amount that is
352 allocated every time after that. */
354 #define OP_SIZE_INIT 0
356 #define OP_SIZE_2 110
357 #define OP_SIZE_3 511
359 /* Initialize the operand cache routines. */
362 init_ssa_operands (void)
364 if (!n_initialized++)
366 build_defs = VEC_alloc (tree, heap, 5);
367 build_uses = VEC_alloc (tree, heap, 10);
368 build_vuses = VEC_alloc (tree, heap, 25);
369 build_vdefs = VEC_alloc (tree, heap, 25);
370 bitmap_obstack_initialize (&operands_bitmap_obstack);
371 build_loads = BITMAP_ALLOC (&operands_bitmap_obstack);
372 build_stores = BITMAP_ALLOC (&operands_bitmap_obstack);
373 scb_stack = VEC_alloc (scb_t, heap, 20);
376 gcc_assert (gimple_ssa_operands (cfun)->operand_memory == NULL);
377 gcc_assert (gimple_ssa_operands (cfun)->mpt_table == NULL);
378 gimple_ssa_operands (cfun)->operand_memory_index
379 = gimple_ssa_operands (cfun)->ssa_operand_mem_size;
380 gimple_ssa_operands (cfun)->ops_active = true;
381 memset (&clobber_stats, 0, sizeof (clobber_stats));
383 gimple_ssa_operands (cfun)->ssa_operand_mem_size = OP_SIZE_INIT;
387 /* Dispose of anything required by the operand routines. */
390 fini_ssa_operands (void)
392 struct ssa_operand_memory_d *ptr;
396 if (!--n_initialized)
398 VEC_free (tree, heap, build_defs);
399 VEC_free (tree, heap, build_uses);
400 VEC_free (tree, heap, build_vdefs);
401 VEC_free (tree, heap, build_vuses);
402 BITMAP_FREE (build_loads);
403 BITMAP_FREE (build_stores);
405 /* The change buffer stack had better be empty. */
406 gcc_assert (VEC_length (scb_t, scb_stack) == 0);
407 VEC_free (scb_t, heap, scb_stack);
411 gimple_ssa_operands (cfun)->free_defs = NULL;
412 gimple_ssa_operands (cfun)->free_uses = NULL;
414 while ((ptr = gimple_ssa_operands (cfun)->operand_memory) != NULL)
416 gimple_ssa_operands (cfun)->operand_memory
417 = gimple_ssa_operands (cfun)->operand_memory->next;
422 VEC_iterate (tree, gimple_ssa_operands (cfun)->mpt_table, ix, mpt);
426 BITMAP_FREE (MPT_SYMBOLS (mpt));
429 VEC_free (tree, heap, gimple_ssa_operands (cfun)->mpt_table);
431 gimple_ssa_operands (cfun)->ops_active = false;
434 bitmap_obstack_release (&operands_bitmap_obstack);
435 if (dump_file && (dump_flags & TDF_STATS))
437 fprintf (dump_file, "Original clobbered vars: %d\n",
438 clobber_stats.clobbered_vars);
439 fprintf (dump_file, "Static write clobbers avoided: %d\n",
440 clobber_stats.static_write_clobbers_avoided);
441 fprintf (dump_file, "Static read clobbers avoided: %d\n",
442 clobber_stats.static_read_clobbers_avoided);
443 fprintf (dump_file, "Unescapable clobbers avoided: %d\n",
444 clobber_stats.unescapable_clobbers_avoided);
445 fprintf (dump_file, "Original read-only clobbers: %d\n",
446 clobber_stats.readonly_clobbers);
447 fprintf (dump_file, "Static read-only clobbers avoided: %d\n",
448 clobber_stats.static_readonly_clobbers_avoided);
453 /* Return memory for operands of SIZE chunks. */
456 ssa_operand_alloc (unsigned size)
460 if (gimple_ssa_operands (cfun)->operand_memory_index + size
461 >= gimple_ssa_operands (cfun)->ssa_operand_mem_size)
463 struct ssa_operand_memory_d *ptr;
465 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size == OP_SIZE_INIT)
466 gimple_ssa_operands (cfun)->ssa_operand_mem_size
467 = OP_SIZE_1 * sizeof (struct voptype_d);
469 if (gimple_ssa_operands (cfun)->ssa_operand_mem_size
470 == OP_SIZE_1 * sizeof (struct voptype_d))
471 gimple_ssa_operands (cfun)->ssa_operand_mem_size
472 = OP_SIZE_2 * sizeof (struct voptype_d);
474 gimple_ssa_operands (cfun)->ssa_operand_mem_size
475 = OP_SIZE_3 * sizeof (struct voptype_d);
477 /* Go right to the maximum size if the request is too large. */
478 if (size > gimple_ssa_operands (cfun)->ssa_operand_mem_size)
479 gimple_ssa_operands (cfun)->ssa_operand_mem_size
480 = OP_SIZE_3 * sizeof (struct voptype_d);
482 /* Fail if there is not enough space. If there are this many operands
483 required, first make sure there isn't a different problem causing this
484 many operands. If the decision is that this is OK, then we can
485 specially allocate a buffer just for this request. */
486 gcc_assert (size <= gimple_ssa_operands (cfun)->ssa_operand_mem_size);
488 ptr = (struct ssa_operand_memory_d *)
489 ggc_alloc (sizeof (struct ssa_operand_memory_d)
490 + gimple_ssa_operands (cfun)->ssa_operand_mem_size - 1);
491 ptr->next = gimple_ssa_operands (cfun)->operand_memory;
492 gimple_ssa_operands (cfun)->operand_memory = ptr;
493 gimple_ssa_operands (cfun)->operand_memory_index = 0;
495 ptr = &(gimple_ssa_operands (cfun)->operand_memory
496 ->mem[gimple_ssa_operands (cfun)->operand_memory_index]);
497 gimple_ssa_operands (cfun)->operand_memory_index += size;
502 /* Allocate a DEF operand. */
504 static inline struct def_optype_d *
507 struct def_optype_d *ret;
508 if (gimple_ssa_operands (cfun)->free_defs)
510 ret = gimple_ssa_operands (cfun)->free_defs;
511 gimple_ssa_operands (cfun)->free_defs
512 = gimple_ssa_operands (cfun)->free_defs->next;
515 ret = (struct def_optype_d *)
516 ssa_operand_alloc (sizeof (struct def_optype_d));
521 /* Allocate a USE operand. */
523 static inline struct use_optype_d *
526 struct use_optype_d *ret;
527 if (gimple_ssa_operands (cfun)->free_uses)
529 ret = gimple_ssa_operands (cfun)->free_uses;
530 gimple_ssa_operands (cfun)->free_uses
531 = gimple_ssa_operands (cfun)->free_uses->next;
534 ret = (struct use_optype_d *)
535 ssa_operand_alloc (sizeof (struct use_optype_d));
540 /* Allocate a vop with NUM elements. */
542 static inline struct voptype_d *
545 struct voptype_d *ret = NULL;
548 int bucket = vop_free_bucket_index (num);
551 /* If there is a free operand, use it. */
552 if (gimple_ssa_operands (cfun)->vop_free_buckets[bucket] != NULL)
554 ret = gimple_ssa_operands (cfun)->vop_free_buckets[bucket];
555 gimple_ssa_operands (cfun)->vop_free_buckets[bucket] =
556 gimple_ssa_operands (cfun)->vop_free_buckets[bucket]->next;
559 alloc_size = vop_free_bucket_size(bucket);
565 ret = (struct voptype_d *)ssa_operand_alloc (
566 sizeof (struct voptype_d) + (alloc_size - 1) * sizeof (vuse_element_t));
568 VUSE_VECT_NUM_ELEM (ret->usev) = num;
573 /* This routine makes sure that PTR is in an immediate use list, and makes
574 sure the stmt pointer is set to the current stmt. */
577 set_virtual_use_link (use_operand_p ptr, tree stmt)
579 /* fold_stmt may have changed the stmt pointers. */
580 if (ptr->stmt != stmt)
583 /* If this use isn't in a list, add it to the correct list. */
585 link_imm_use (ptr, *(ptr->use));
589 /* Adds OP to the list of defs after LAST. */
591 static inline def_optype_p
592 add_def_op (tree *op, def_optype_p last)
594 def_optype_p new_def;
596 new_def = alloc_def ();
597 DEF_OP_PTR (new_def) = op;
598 last->next = new_def;
599 new_def->next = NULL;
604 /* Adds OP to the list of uses of statement STMT after LAST. */
606 static inline use_optype_p
607 add_use_op (tree stmt, tree *op, use_optype_p last)
609 use_optype_p new_use;
611 new_use = alloc_use ();
612 USE_OP_PTR (new_use)->use = op;
613 link_imm_use_stmt (USE_OP_PTR (new_use), *op, stmt);
614 last->next = new_use;
615 new_use->next = NULL;
620 /* Return a virtual op pointer with NUM elements which are all initialized to OP
621 and are linked into the immediate uses for STMT. The new vop is appended
624 static inline voptype_p
625 add_vop (tree stmt, tree op, int num, voptype_p prev)
630 new_vop = alloc_vop (num);
631 for (x = 0; x < num; x++)
633 VUSE_OP_PTR (new_vop, x)->prev = NULL;
634 SET_VUSE_OP (new_vop, x, op);
635 VUSE_OP_PTR (new_vop, x)->use = &new_vop->usev.uses[x].use_var;
636 link_imm_use_stmt (VUSE_OP_PTR (new_vop, x),
637 new_vop->usev.uses[x].use_var, stmt);
641 prev->next = new_vop;
642 new_vop->next = NULL;
647 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
648 LAST to the new element. */
650 static inline voptype_p
651 add_vuse_op (tree stmt, tree op, int num, voptype_p last)
653 voptype_p new_vop = add_vop (stmt, op, num, last);
654 VDEF_RESULT (new_vop) = NULL_TREE;
659 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
660 LAST to the new element. */
662 static inline voptype_p
663 add_vdef_op (tree stmt, tree op, int num, voptype_p last)
665 voptype_p new_vop = add_vop (stmt, op, num, last);
666 VDEF_RESULT (new_vop) = op;
671 /* Takes elements from build_defs and turns them into def operands of STMT.
672 TODO -- Make build_defs VEC of tree *. */
675 finalize_ssa_defs (tree stmt)
678 struct def_optype_d new_list;
679 def_optype_p old_ops, last;
680 unsigned int num = VEC_length (tree, build_defs);
682 /* There should only be a single real definition per assignment. */
683 gcc_assert ((stmt && TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) || num <= 1);
685 new_list.next = NULL;
688 old_ops = DEF_OPS (stmt);
692 /* Check for the common case of 1 def that hasn't changed. */
693 if (old_ops && old_ops->next == NULL && num == 1
694 && (tree *) VEC_index (tree, build_defs, 0) == DEF_OP_PTR (old_ops))
697 /* If there is anything in the old list, free it. */
700 old_ops->next = gimple_ssa_operands (cfun)->free_defs;
701 gimple_ssa_operands (cfun)->free_defs = old_ops;
704 /* If there is anything remaining in the build_defs list, simply emit it. */
705 for ( ; new_i < num; new_i++)
706 last = add_def_op ((tree *) VEC_index (tree, build_defs, new_i), last);
708 /* Now set the stmt's operands. */
709 DEF_OPS (stmt) = new_list.next;
711 #ifdef ENABLE_CHECKING
715 for (ptr = DEF_OPS (stmt); ptr; ptr = ptr->next)
718 gcc_assert (x == num);
724 /* Takes elements from build_uses and turns them into use operands of STMT.
725 TODO -- Make build_uses VEC of tree *. */
728 finalize_ssa_uses (tree stmt)
731 struct use_optype_d new_list;
732 use_optype_p old_ops, ptr, last;
734 #ifdef ENABLE_CHECKING
737 unsigned num = VEC_length (tree, build_uses);
739 /* If the pointer to the operand is the statement itself, something is
740 wrong. It means that we are pointing to a local variable (the
741 initial call to update_stmt_operands does not pass a pointer to a
743 for (x = 0; x < num; x++)
744 gcc_assert (*((tree *)VEC_index (tree, build_uses, x)) != stmt);
748 new_list.next = NULL;
751 old_ops = USE_OPS (stmt);
753 /* If there is anything in the old list, free it. */
756 for (ptr = old_ops; ptr; ptr = ptr->next)
757 delink_imm_use (USE_OP_PTR (ptr));
758 old_ops->next = gimple_ssa_operands (cfun)->free_uses;
759 gimple_ssa_operands (cfun)->free_uses = old_ops;
762 /* Now create nodes for all the new nodes. */
763 for (new_i = 0; new_i < VEC_length (tree, build_uses); new_i++)
764 last = add_use_op (stmt,
765 (tree *) VEC_index (tree, build_uses, new_i),
768 /* Now set the stmt's operands. */
769 USE_OPS (stmt) = new_list.next;
771 #ifdef ENABLE_CHECKING
774 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
777 gcc_assert (x == VEC_length (tree, build_uses));
783 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
784 STMT. FIXME, for now VDEF operators should have a single operand
788 finalize_ssa_vdefs (tree stmt)
791 struct voptype_d new_list;
792 voptype_p old_ops, ptr, last;
793 stmt_ann_t ann = stmt_ann (stmt);
795 /* Set the symbols referenced by STMT. */
796 if (!bitmap_empty_p (build_stores))
798 if (ann->operands.stores == NULL)
799 ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
801 bitmap_copy (ann->operands.stores, build_stores);
804 BITMAP_FREE (ann->operands.stores);
806 /* If aliases have not been computed, do not instantiate a virtual
807 operator on STMT. Initially, we only compute the SSA form on
808 GIMPLE registers. The virtual SSA form is only computed after
809 alias analysis, so virtual operators will remain unrenamed and
810 the verifier will complain. However, alias analysis needs to
811 access symbol load/store information, so we need to compute
813 if (!gimple_aliases_computed_p (cfun))
816 new_list.next = NULL;
819 old_ops = VDEF_OPS (stmt);
821 while (old_ops && new_i < VEC_length (tree, build_vdefs))
823 tree op = VEC_index (tree, build_vdefs, new_i);
824 unsigned new_uid = get_name_decl (op);
825 unsigned old_uid = get_name_decl (VDEF_RESULT (old_ops));
827 /* FIXME, for now each VDEF operator should have at most one
828 operand in their RHS. */
829 gcc_assert (VDEF_NUM (old_ops) == 1);
831 if (old_uid == new_uid)
833 /* If the symbols are the same, reuse the existing operand. */
834 last->next = old_ops;
836 old_ops = old_ops->next;
838 set_virtual_use_link (VDEF_OP_PTR (last, 0), stmt);
841 else if (old_uid < new_uid)
843 /* If old is less than new, old goes to the free list. */
845 delink_imm_use (VDEF_OP_PTR (old_ops, 0));
846 next = old_ops->next;
847 add_vop_to_freelist (old_ops);
852 /* This is a new operand. */
853 last = add_vdef_op (stmt, op, 1, last);
858 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
859 for ( ; new_i < VEC_length (tree, build_vdefs); new_i++)
860 last = add_vdef_op (stmt, VEC_index (tree, build_vdefs, new_i), 1, last);
862 /* If there is anything in the old list, free it. */
865 for (ptr = old_ops; ptr; ptr = last)
868 delink_imm_use (VDEF_OP_PTR (ptr, 0));
869 add_vop_to_freelist (ptr);
873 /* Now set STMT's operands. */
874 VDEF_OPS (stmt) = new_list.next;
876 #ifdef ENABLE_CHECKING
879 for (ptr = VDEF_OPS (stmt); ptr; ptr = ptr->next)
882 gcc_assert (x == VEC_length (tree, build_vdefs));
888 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
892 finalize_ssa_vuse_ops (tree stmt)
894 unsigned new_i, old_i;
895 voptype_p old_ops, last;
896 VEC(tree,heap) *new_ops;
899 /* Set the symbols referenced by STMT. */
900 ann = stmt_ann (stmt);
901 if (!bitmap_empty_p (build_loads))
903 if (ann->operands.loads == NULL)
904 ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
906 bitmap_copy (ann->operands.loads, build_loads);
909 BITMAP_FREE (ann->operands.loads);
911 /* If aliases have not been computed, do not instantiate a virtual
912 operator on STMT. Initially, we only compute the SSA form on
913 GIMPLE registers. The virtual SSA form is only computed after
914 alias analysis, so virtual operators will remain unrenamed and
915 the verifier will complain. However, alias analysis needs to
916 access symbol load/store information, so we need to compute
918 if (!gimple_aliases_computed_p (cfun))
921 /* STMT should have at most one VUSE operator. */
922 old_ops = VUSE_OPS (stmt);
923 gcc_assert (old_ops == NULL || old_ops->next == NULL);
928 && old_i < VUSE_NUM (old_ops)
929 && new_i < VEC_length (tree, build_vuses))
931 tree new_op = VEC_index (tree, build_vuses, new_i);
932 tree old_op = VUSE_OP (old_ops, old_i);
933 unsigned new_uid = get_name_decl (new_op);
934 unsigned old_uid = get_name_decl (old_op);
936 if (old_uid == new_uid)
938 /* If the symbols are the same, reuse the existing operand. */
939 VEC_safe_push (tree, heap, new_ops, old_op);
943 else if (old_uid < new_uid)
945 /* If OLD_UID is less than NEW_UID, the old operand has
946 disappeared, skip to the next old operand. */
951 /* This is a new operand. */
952 VEC_safe_push (tree, heap, new_ops, new_op);
957 /* If there is anything remaining in the build_vuses list, simply emit it. */
958 for ( ; new_i < VEC_length (tree, build_vuses); new_i++)
959 VEC_safe_push (tree, heap, new_ops, VEC_index (tree, build_vuses, new_i));
961 /* If there is anything in the old list, free it. */
964 for (old_i = 0; old_i < VUSE_NUM (old_ops); old_i++)
965 delink_imm_use (VUSE_OP_PTR (old_ops, old_i));
966 add_vop_to_freelist (old_ops);
967 VUSE_OPS (stmt) = NULL;
970 /* If there are any operands, instantiate a VUSE operator for STMT. */
976 last = add_vuse_op (stmt, NULL, VEC_length (tree, new_ops), NULL);
978 for (i = 0; VEC_iterate (tree, new_ops, i, op); i++)
979 SET_USE (VUSE_OP_PTR (last, (int) i), op);
981 VUSE_OPS (stmt) = last;
982 VEC_free (tree, heap, new_ops);
985 #ifdef ENABLE_CHECKING
991 gcc_assert (VUSE_OPS (stmt)->next == NULL);
992 x = VUSE_NUM (VUSE_OPS (stmt));
997 gcc_assert (x == VEC_length (tree, build_vuses));
1002 /* Return a new VUSE operand vector for STMT. */
1005 finalize_ssa_vuses (tree stmt)
1007 unsigned num, num_vdefs;
1008 unsigned vuse_index;
1010 /* Remove superfluous VUSE operands. If the statement already has a
1011 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1012 needed because VDEFs imply a VUSE of the variable. For instance,
1013 suppose that variable 'a' is pointed-to by p and q:
1019 The VUSE <a_2> is superfluous because it is implied by the
1021 num = VEC_length (tree, build_vuses);
1022 num_vdefs = VEC_length (tree, build_vdefs);
1024 if (num > 0 && num_vdefs > 0)
1025 for (vuse_index = 0; vuse_index < VEC_length (tree, build_vuses); )
1028 vuse = VEC_index (tree, build_vuses, vuse_index);
1029 if (TREE_CODE (vuse) != SSA_NAME)
1031 var_ann_t ann = var_ann (vuse);
1032 ann->in_vuse_list = 0;
1033 if (ann->in_vdef_list)
1035 VEC_ordered_remove (tree, build_vuses, vuse_index);
1042 finalize_ssa_vuse_ops (stmt);
1046 /* Clear the in_list bits and empty the build array for VDEFs and
1050 cleanup_build_arrays (void)
1055 for (i = 0; VEC_iterate (tree, build_vdefs, i, t); i++)
1056 if (TREE_CODE (t) != SSA_NAME)
1057 var_ann (t)->in_vdef_list = false;
1059 for (i = 0; VEC_iterate (tree, build_vuses, i, t); i++)
1060 if (TREE_CODE (t) != SSA_NAME)
1061 var_ann (t)->in_vuse_list = false;
1063 VEC_truncate (tree, build_vdefs, 0);
1064 VEC_truncate (tree, build_vuses, 0);
1065 VEC_truncate (tree, build_defs, 0);
1066 VEC_truncate (tree, build_uses, 0);
1067 bitmap_clear (build_loads);
1068 bitmap_clear (build_stores);
1072 /* Finalize all the build vectors, fill the new ones into INFO. */
1075 finalize_ssa_stmt_operands (tree stmt)
1077 finalize_ssa_defs (stmt);
1078 finalize_ssa_uses (stmt);
1079 finalize_ssa_vdefs (stmt);
1080 finalize_ssa_vuses (stmt);
1081 cleanup_build_arrays ();
1085 /* Start the process of building up operands vectors in INFO. */
1088 start_ssa_stmt_operands (void)
1090 gcc_assert (VEC_length (tree, build_defs) == 0);
1091 gcc_assert (VEC_length (tree, build_uses) == 0);
1092 gcc_assert (VEC_length (tree, build_vuses) == 0);
1093 gcc_assert (VEC_length (tree, build_vdefs) == 0);
1094 gcc_assert (bitmap_empty_p (build_loads));
1095 gcc_assert (bitmap_empty_p (build_stores));
1099 /* Add DEF_P to the list of pointers to operands. */
1102 append_def (tree *def_p)
1104 VEC_safe_push (tree, heap, build_defs, (tree) def_p);
1108 /* Add USE_P to the list of pointers to operands. */
1111 append_use (tree *use_p)
1113 VEC_safe_push (tree, heap, build_uses, (tree) use_p);
1117 /* Add VAR to the set of variables that require a VDEF operator. */
1120 append_vdef (tree var)
1124 if (TREE_CODE (var) != SSA_NAME)
1129 /* If VAR belongs to a memory partition, use it instead of VAR. */
1130 mpt = memory_partition (var);
1134 /* Don't allow duplicate entries. */
1135 ann = get_var_ann (var);
1136 if (ann->in_vdef_list)
1139 ann->in_vdef_list = true;
1143 sym = SSA_NAME_VAR (var);
1145 VEC_safe_push (tree, heap, build_vdefs, var);
1146 bitmap_set_bit (build_stores, DECL_UID (sym));
1150 /* Add VAR to the set of variables that require a VUSE operator. */
1153 append_vuse (tree var)
1157 if (TREE_CODE (var) != SSA_NAME)
1162 /* If VAR belongs to a memory partition, use it instead of VAR. */
1163 mpt = memory_partition (var);
1167 /* Don't allow duplicate entries. */
1168 ann = get_var_ann (var);
1169 if (ann->in_vuse_list || ann->in_vdef_list)
1172 ann->in_vuse_list = true;
1176 sym = SSA_NAME_VAR (var);
1178 VEC_safe_push (tree, heap, build_vuses, var);
1179 bitmap_set_bit (build_loads, DECL_UID (sym));
1183 /* REF is a tree that contains the entire pointer dereference
1184 expression, if available, or NULL otherwise. ALIAS is the variable
1185 we are asking if REF can access. OFFSET and SIZE come from the
1186 memory access expression that generated this virtual operand. */
1189 access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset,
1192 bool offsetgtz = offset > 0;
1193 unsigned HOST_WIDE_INT uoffset = (unsigned HOST_WIDE_INT) offset;
1194 tree base = ref ? get_base_address (ref) : NULL;
1196 /* If ALIAS is .GLOBAL_VAR then the memory reference REF must be
1197 using a call-clobbered memory tag. By definition, call-clobbered
1198 memory tags can always touch .GLOBAL_VAR. */
1199 if (alias == gimple_global_var (cfun))
1202 /* If ALIAS is an SFT, it can't be touched if the offset
1203 and size of the access is not overlapping with the SFT offset and
1204 size. This is only true if we are accessing through a pointer
1205 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1206 be accessing through a pointer to some substruct of the
1207 structure, and if we try to prune there, we will have the wrong
1208 offset, and get the wrong answer.
1209 i.e., we can't prune without more work if we have something like
1215 const char *byte_op;
1223 foo = &targetm.asm_out.aligned_op;
1226 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1227 terms of SFT_PARENT_VAR, that is where it is.
1228 However, the access through the foo pointer will be at offset 0. */
1230 && TREE_CODE (alias) == STRUCT_FIELD_TAG
1232 && TREE_TYPE (base) == TREE_TYPE (SFT_PARENT_VAR (alias))
1233 && !overlap_subvar (offset, size, alias, NULL))
1235 #ifdef ACCESS_DEBUGGING
1236 fprintf (stderr, "Access to ");
1237 print_generic_expr (stderr, ref, 0);
1238 fprintf (stderr, " may not touch ");
1239 print_generic_expr (stderr, alias, 0);
1240 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1245 /* Without strict aliasing, it is impossible for a component access
1246 through a pointer to touch a random variable, unless that
1247 variable *is* a structure or a pointer.
1249 That is, given p->c, and some random global variable b,
1250 there is no legal way that p->c could be an access to b.
1252 Without strict aliasing on, we consider it legal to do something
1255 struct foos { int l; };
1257 static struct foos *getfoo(void);
1260 struct foos *f = getfoo();
1267 static struct foos *getfoo(void)
1268 { return (struct foos *)&foo; }
1270 (taken from 20000623-1.c)
1272 The docs also say/imply that access through union pointers
1273 is legal (but *not* if you take the address of the union member,
1274 i.e. the inverse), such that you can do
1284 U *pretmp = (U*)&rv;
1288 To implement this, we just punt on accesses through union
1292 && flag_strict_aliasing
1293 && TREE_CODE (ref) != INDIRECT_REF
1295 && (TREE_CODE (base) != INDIRECT_REF
1296 || TREE_CODE (TREE_TYPE (base)) != UNION_TYPE)
1297 && !AGGREGATE_TYPE_P (TREE_TYPE (alias))
1298 && TREE_CODE (TREE_TYPE (alias)) != COMPLEX_TYPE
1299 && !var_ann (alias)->is_heapvar
1300 /* When the struct has may_alias attached to it, we need not to
1302 && get_alias_set (base))
1304 #ifdef ACCESS_DEBUGGING
1305 fprintf (stderr, "Access to ");
1306 print_generic_expr (stderr, ref, 0);
1307 fprintf (stderr, " may not touch ");
1308 print_generic_expr (stderr, alias, 0);
1309 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1314 /* If the offset of the access is greater than the size of one of
1315 the possible aliases, it can't be touching that alias, because it
1316 would be past the end of the structure. */
1318 && flag_strict_aliasing
1319 && TREE_CODE (ref) != INDIRECT_REF
1321 && !POINTER_TYPE_P (TREE_TYPE (alias))
1323 && DECL_SIZE (alias)
1324 && TREE_CODE (DECL_SIZE (alias)) == INTEGER_CST
1325 && uoffset > TREE_INT_CST_LOW (DECL_SIZE (alias)))
1327 #ifdef ACCESS_DEBUGGING
1328 fprintf (stderr, "Access to ");
1329 print_generic_expr (stderr, ref, 0);
1330 fprintf (stderr, " may not touch ");
1331 print_generic_expr (stderr, alias, 0);
1332 fprintf (stderr, " in function %s\n", get_name (current_function_decl));
1341 /* Add VAR to the virtual operands array. FLAGS is as in
1342 get_expr_operands. FULL_REF is a tree that contains the entire
1343 pointer dereference expression, if available, or NULL otherwise.
1344 OFFSET and SIZE come from the memory access expression that
1345 generated this virtual operand. IS_CALL_SITE is true if the
1346 affected statement is a call site. */
1349 add_virtual_operand (tree var, stmt_ann_t s_ann, int flags,
1350 tree full_ref, HOST_WIDE_INT offset,
1351 HOST_WIDE_INT size, bool is_call_site)
1353 bitmap aliases = NULL;
1357 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1358 v_ann = var_ann (sym);
1360 /* Mark the statement as having memory operands. */
1361 s_ann->references_memory = true;
1363 /* Mark statements with volatile operands. Optimizers should back
1364 off from statements having volatile operands. */
1365 if (TREE_THIS_VOLATILE (sym) && s_ann)
1366 s_ann->has_volatile_ops = true;
1368 /* If the variable cannot be modified and this is a VDEF change
1369 it into a VUSE. This happens when read-only variables are marked
1370 call-clobbered and/or aliased to writable variables. So we only
1371 check that this only happens on non-specific stores.
1373 Note that if this is a specific store, i.e. associated with a
1374 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1375 into validation problems.
1377 This can happen when programs cast away const, leaving us with a
1378 store to read-only memory. If the statement is actually executed
1379 at runtime, then the program is ill formed. If the statement is
1380 not executed then all is well. At the very least, we cannot ICE. */
1381 if ((flags & opf_implicit) && unmodifiable_var_p (var))
1384 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1385 virtual operands, unless the caller has specifically requested
1386 not to add virtual operands (used when adding operands inside an
1387 ADDR_EXPR expression). */
1388 if (flags & opf_no_vops)
1392 aliases = MTAG_ALIASES (var);
1394 if (aliases == NULL)
1396 if (s_ann && !gimple_aliases_computed_p (cfun))
1397 s_ann->has_volatile_ops = true;
1399 /* The variable is not aliased or it is an alias tag. */
1400 if (flags & opf_def)
1411 /* The variable is aliased. Add its aliases to the virtual
1413 gcc_assert (!bitmap_empty_p (aliases));
1415 if (flags & opf_def)
1417 bool none_added = true;
1418 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1420 al = referenced_var (i);
1421 if (!access_can_touch_variable (full_ref, al, offset, size))
1424 /* Call-clobbered tags may have non-call-clobbered
1425 symbols in their alias sets. Ignore them if we are
1426 adding VOPs for a call site. */
1427 if (is_call_site && !is_call_clobbered (al))
1434 /* If the variable is also an alias tag, add a virtual
1435 operand for it, otherwise we will miss representing
1436 references to the members of the variable's alias set.
1437 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1439 It is also necessary to add bare defs on clobbers for
1440 SMT's, so that bare SMT uses caused by pruning all the
1441 aliases will link up properly with calls. In order to
1442 keep the number of these bare defs we add down to the
1443 minimum necessary, we keep track of which SMT's were used
1444 alone in statement vdefs or VUSEs. */
1446 || (TREE_CODE (var) == SYMBOL_MEMORY_TAG
1454 bool none_added = true;
1455 EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
1457 al = referenced_var (i);
1458 if (!access_can_touch_variable (full_ref, al, offset, size))
1461 /* Call-clobbered tags may have non-call-clobbered
1462 symbols in their alias sets. Ignore them if we are
1463 adding VOPs for a call site. */
1464 if (is_call_site && !is_call_clobbered (al))
1471 /* Even if no aliases have been added, we still need to
1472 establish def-use and use-def chains, lest
1473 transformations think that this is not a memory
1474 reference. For an example of this scenario, see
1475 testsuite/g++.dg/opt/cleanup1.C. */
1483 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1484 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1485 the statement's real operands, otherwise it is added to virtual
1489 add_stmt_operand (tree *var_p, stmt_ann_t s_ann, int flags)
1494 gcc_assert (SSA_VAR_P (*var_p) && s_ann);
1497 sym = (TREE_CODE (var) == SSA_NAME ? SSA_NAME_VAR (var) : var);
1498 v_ann = var_ann (sym);
1500 /* Mark statements with volatile operands. */
1501 if (TREE_THIS_VOLATILE (sym))
1502 s_ann->has_volatile_ops = true;
1504 if (is_gimple_reg (sym))
1506 /* The variable is a GIMPLE register. Add it to real operands. */
1507 if (flags & opf_def)
1513 add_virtual_operand (var, s_ann, flags, NULL_TREE, 0, -1, false);
1517 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1518 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1520 STMT is the statement being processed, EXPR is the INDIRECT_REF
1523 FLAGS is as in get_expr_operands.
1525 FULL_REF contains the full pointer dereference expression, if we
1526 have it, or NULL otherwise.
1528 OFFSET and SIZE are the location of the access inside the
1529 dereferenced pointer, if known.
1531 RECURSE_ON_BASE should be set to true if we want to continue
1532 calling get_expr_operands on the base pointer, and false if
1533 something else will do it for us. */
1536 get_indirect_ref_operands (tree stmt, tree expr, int flags,
1538 HOST_WIDE_INT offset, HOST_WIDE_INT size,
1539 bool recurse_on_base)
1541 tree *pptr = &TREE_OPERAND (expr, 0);
1543 stmt_ann_t s_ann = stmt_ann (stmt);
1545 s_ann->references_memory = true;
1546 if (s_ann && TREE_THIS_VOLATILE (expr))
1547 s_ann->has_volatile_ops = true;
1549 if (SSA_VAR_P (ptr))
1551 struct ptr_info_def *pi = NULL;
1553 /* If PTR has flow-sensitive points-to information, use it. */
1554 if (TREE_CODE (ptr) == SSA_NAME
1555 && (pi = SSA_NAME_PTR_INFO (ptr)) != NULL
1556 && pi->name_mem_tag)
1558 /* PTR has its own memory tag. Use it. */
1559 add_virtual_operand (pi->name_mem_tag, s_ann, flags,
1560 full_ref, offset, size, false);
1564 /* If PTR is not an SSA_NAME or it doesn't have a name
1565 tag, use its symbol memory tag. */
1568 /* If we are emitting debugging dumps, display a warning if
1569 PTR is an SSA_NAME with no flow-sensitive alias
1570 information. That means that we may need to compute
1573 && TREE_CODE (ptr) == SSA_NAME
1577 "NOTE: no flow-sensitive alias info for ");
1578 print_generic_expr (dump_file, ptr, dump_flags);
1579 fprintf (dump_file, " in ");
1580 print_generic_stmt (dump_file, stmt, dump_flags);
1583 if (TREE_CODE (ptr) == SSA_NAME)
1584 ptr = SSA_NAME_VAR (ptr);
1585 v_ann = var_ann (ptr);
1587 if (v_ann->symbol_mem_tag)
1588 add_virtual_operand (v_ann->symbol_mem_tag, s_ann, flags,
1589 full_ref, offset, size, false);
1591 /* Aliasing information is missing; mark statement as
1592 volatile so we won't optimize it out too actively. */
1594 && !gimple_aliases_computed_p (cfun)
1595 && (flags & opf_def))
1596 s_ann->has_volatile_ops = true;
1599 else if (TREE_CODE (ptr) == INTEGER_CST)
1601 /* If a constant is used as a pointer, we can't generate a real
1602 operand for it but we mark the statement volatile to prevent
1603 optimizations from messing things up. */
1605 s_ann->has_volatile_ops = true;
1610 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1614 /* If requested, add a USE operand for the base pointer. */
1615 if (recurse_on_base)
1616 get_expr_operands (stmt, pptr, opf_use);
1620 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1623 get_tmr_operands (tree stmt, tree expr, int flags)
1626 HOST_WIDE_INT offset, size, maxsize;
1628 stmt_ann_t s_ann = stmt_ann (stmt);
1630 /* This statement references memory. */
1631 s_ann->references_memory = 1;
1633 /* First record the real operands. */
1634 get_expr_operands (stmt, &TMR_BASE (expr), opf_use);
1635 get_expr_operands (stmt, &TMR_INDEX (expr), opf_use);
1637 if (TMR_SYMBOL (expr))
1638 add_to_addressable_set (TMR_SYMBOL (expr), &s_ann->addresses_taken);
1640 tag = TMR_TAG (expr);
1643 /* Something weird, so ensure that we will be careful. */
1644 s_ann->has_volatile_ops = true;
1650 get_expr_operands (stmt, &tag, flags);
1654 ref = get_ref_base_and_extent (tag, &offset, &size, &maxsize);
1655 gcc_assert (ref != NULL_TREE);
1656 svars = get_subvars_for_var (ref);
1657 for (sv = svars; sv; sv = sv->next)
1661 if (overlap_subvar (offset, maxsize, sv->var, &exact))
1662 add_stmt_operand (&sv->var, s_ann, flags);
1667 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1668 clobbered variables in the function. */
1671 add_call_clobber_ops (tree stmt, tree callee)
1675 stmt_ann_t s_ann = stmt_ann (stmt);
1676 bitmap not_read_b, not_written_b;
1678 /* Functions that are not const, pure or never return may clobber
1679 call-clobbered variables. */
1681 s_ann->makes_clobbering_call = true;
1683 /* If we created .GLOBAL_VAR earlier, just use it. */
1684 if (gimple_global_var (cfun))
1686 tree var = gimple_global_var (cfun);
1687 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1691 /* Get info for local and module level statics. There is a bit
1692 set for each static if the call being processed does not read
1693 or write that variable. */
1694 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1695 not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL;
1697 /* Add a VDEF operand for every call clobbered variable. */
1698 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1700 tree var = referenced_var_lookup (u);
1701 unsigned int escape_mask = var_ann (var)->escape_mask;
1702 tree real_var = var;
1706 /* Not read and not written are computed on regular vars, not
1707 subvars, so look at the parent var if this is an SFT. */
1708 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1709 real_var = SFT_PARENT_VAR (var);
1711 not_read = not_read_b
1712 ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1715 not_written = not_written_b
1716 ? bitmap_bit_p (not_written_b, DECL_UID (real_var))
1718 gcc_assert (!unmodifiable_var_p (var));
1720 clobber_stats.clobbered_vars++;
1722 /* See if this variable is really clobbered by this function. */
1724 /* Trivial case: Things escaping only to pure/const are not
1725 clobbered by non-pure-const, and only read by pure/const. */
1726 if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
1728 tree call = get_call_expr_in (stmt);
1729 if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
1731 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1732 clobber_stats.unescapable_clobbers_avoided++;
1737 clobber_stats.unescapable_clobbers_avoided++;
1744 clobber_stats.static_write_clobbers_avoided++;
1746 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1748 clobber_stats.static_read_clobbers_avoided++;
1751 add_virtual_operand (var, s_ann, opf_def, NULL, 0, -1, true);
1756 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1760 add_call_read_ops (tree stmt, tree callee)
1764 stmt_ann_t s_ann = stmt_ann (stmt);
1767 /* if the function is not pure, it may reference memory. Add
1768 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1769 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1770 if (gimple_global_var (cfun))
1772 tree var = gimple_global_var (cfun);
1773 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1777 not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
1779 /* Add a VUSE for each call-clobbered variable. */
1780 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
1782 tree var = referenced_var (u);
1783 tree real_var = var;
1786 clobber_stats.readonly_clobbers++;
1788 /* Not read and not written are computed on regular vars, not
1789 subvars, so look at the parent var if this is an SFT. */
1791 if (TREE_CODE (var) == STRUCT_FIELD_TAG)
1792 real_var = SFT_PARENT_VAR (var);
1794 not_read = not_read_b ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
1799 clobber_stats.static_readonly_clobbers_avoided++;
1803 add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
1808 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1811 get_call_expr_operands (tree stmt, tree expr)
1813 int call_flags = call_expr_flags (expr);
1815 stmt_ann_t ann = stmt_ann (stmt);
1817 ann->references_memory = true;
1819 /* If aliases have been computed already, add VDEF or VUSE
1820 operands for all the symbols that have been found to be
1822 if (gimple_aliases_computed_p (cfun)
1823 && !(call_flags & ECF_NOVOPS))
1825 /* A 'pure' or a 'const' function never call-clobbers anything.
1826 A 'noreturn' function might, but since we don't return anyway
1827 there is no point in recording that. */
1828 if (TREE_SIDE_EFFECTS (expr)
1829 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1830 add_call_clobber_ops (stmt, get_callee_fndecl (expr));
1831 else if (!(call_flags & ECF_CONST))
1832 add_call_read_ops (stmt, get_callee_fndecl (expr));
1835 /* Find uses in the called function. */
1836 get_expr_operands (stmt, &CALL_EXPR_FN (expr), opf_use);
1837 nargs = call_expr_nargs (expr);
1838 for (i = 0; i < nargs; i++)
1839 get_expr_operands (stmt, &CALL_EXPR_ARG (expr, i), opf_use);
1841 get_expr_operands (stmt, &CALL_EXPR_STATIC_CHAIN (expr), opf_use);
1845 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1848 get_asm_expr_operands (tree stmt)
1852 const char **oconstraints;
1853 const char *constraint;
1854 bool allows_mem, allows_reg, is_inout;
1857 s_ann = stmt_ann (stmt);
1858 noutputs = list_length (ASM_OUTPUTS (stmt));
1859 oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));
1861 /* Gather all output operands. */
1862 for (i = 0, link = ASM_OUTPUTS (stmt); link; i++, link = TREE_CHAIN (link))
1864 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1865 oconstraints[i] = constraint;
1866 parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
1867 &allows_reg, &is_inout);
1869 /* This should have been split in gimplify_asm_expr. */
1870 gcc_assert (!allows_reg || !is_inout);
1872 /* Memory operands are addressable. Note that STMT needs the
1873 address of this operand. */
1874 if (!allows_reg && allows_mem)
1876 tree t = get_base_address (TREE_VALUE (link));
1877 if (t && DECL_P (t) && s_ann)
1878 add_to_addressable_set (t, &s_ann->addresses_taken);
1881 get_expr_operands (stmt, &TREE_VALUE (link), opf_def);
1884 /* Gather all input operands. */
1885 for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
1887 constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
1888 parse_input_constraint (&constraint, 0, 0, noutputs, 0, oconstraints,
1889 &allows_mem, &allows_reg);
1891 /* Memory operands are addressable. Note that STMT needs the
1892 address of this operand. */
1893 if (!allows_reg && allows_mem)
1895 tree t = get_base_address (TREE_VALUE (link));
1896 if (t && DECL_P (t) && s_ann)
1897 add_to_addressable_set (t, &s_ann->addresses_taken);
1900 get_expr_operands (stmt, &TREE_VALUE (link), 0);
1903 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1904 for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
1905 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link)), "memory") == 0)
1910 s_ann->references_memory = true;
1912 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, i, bi)
1914 tree var = referenced_var (i);
1915 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1918 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun), 0, i, bi)
1920 tree var = referenced_var (i);
1922 /* Subvars are explicitly represented in this list, so we
1923 don't need the original to be added to the clobber ops,
1924 but the original *will* be in this list because we keep
1925 the addressability of the original variable up-to-date
1926 to avoid confusing the back-end. */
1927 if (var_can_have_subvars (var)
1928 && get_subvars_for_var (var) != NULL)
1931 add_stmt_operand (&var, s_ann, opf_def | opf_implicit);
1938 /* Scan operands for the assignment expression EXPR in statement STMT. */
1941 get_modify_stmt_operands (tree stmt, tree expr)
1943 /* First get operands from the RHS. */
1944 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 1), opf_use);
1946 /* For the LHS, use a regular definition (opf_def) for GIMPLE
1947 registers. If the LHS is a store to memory, we will need
1948 a preserving definition (VDEF).
1950 Preserving definitions are those that modify a part of an
1951 aggregate object for which no subvars have been computed (or the
1952 reference does not correspond exactly to one of them). Stores
1953 through a pointer are also represented with VDEF operators.
1955 We used to distinguish between preserving and killing definitions.
1956 We always emit preserving definitions now. */
1957 get_expr_operands (stmt, &GIMPLE_STMT_OPERAND (expr, 0), opf_def);
1961 /* Recursively scan the expression pointed to by EXPR_P in statement
1962 STMT. FLAGS is one of the OPF_* constants modifying how to
1963 interpret the operands found. */
1966 get_expr_operands (tree stmt, tree *expr_p, int flags)
1968 enum tree_code code;
1969 enum tree_code_class codeclass;
1970 tree expr = *expr_p;
1971 stmt_ann_t s_ann = stmt_ann (stmt);
1976 code = TREE_CODE (expr);
1977 codeclass = TREE_CODE_CLASS (code);
1982 /* Taking the address of a variable does not represent a
1983 reference to it, but the fact that the statement takes its
1984 address will be of interest to some passes (e.g. alias
1986 add_to_addressable_set (TREE_OPERAND (expr, 0), &s_ann->addresses_taken);
1988 /* If the address is invariant, there may be no interesting
1989 variable references inside. */
1990 if (is_gimple_min_invariant (expr))
1993 /* Otherwise, there may be variables referenced inside but there
1994 should be no VUSEs created, since the referenced objects are
1995 not really accessed. The only operands that we should find
1996 here are ARRAY_REF indices which will always be real operands
1997 (GIMPLE does not allow non-registers as array indices). */
1998 flags |= opf_no_vops;
1999 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2003 case STRUCT_FIELD_TAG:
2004 case SYMBOL_MEMORY_TAG:
2005 case NAME_MEMORY_TAG:
2006 add_stmt_operand (expr_p, s_ann, flags);
2015 /* Add the subvars for a variable, if it has subvars, to DEFS
2016 or USES. Otherwise, add the variable itself. Whether it
2017 goes to USES or DEFS depends on the operand flags. */
2018 if (var_can_have_subvars (expr)
2019 && (svars = get_subvars_for_var (expr)))
2022 for (sv = svars; sv; sv = sv->next)
2023 add_stmt_operand (&sv->var, s_ann, flags);
2026 add_stmt_operand (expr_p, s_ann, flags);
2031 case MISALIGNED_INDIRECT_REF:
2032 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2035 case ALIGN_INDIRECT_REF:
2037 get_indirect_ref_operands (stmt, expr, flags, NULL_TREE, 0, -1, true);
2040 case TARGET_MEM_REF:
2041 get_tmr_operands (stmt, expr, flags);
2045 case ARRAY_RANGE_REF:
2051 HOST_WIDE_INT offset, size, maxsize;
2054 /* This component reference becomes an access to all of the
2055 subvariables it can touch, if we can determine that, but
2056 *NOT* the real one. If we can't determine which fields we
2057 could touch, the recursion will eventually get to a
2058 variable and add *all* of its subvars, or whatever is the
2059 minimum correct subset. */
2060 ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
2061 if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
2064 subvar_t svars = get_subvars_for_var (ref);
2066 for (sv = svars; sv; sv = sv->next)
2070 if (overlap_subvar (offset, maxsize, sv->var, &exact))
2072 int subvar_flags = flags;
2074 add_stmt_operand (&sv->var, s_ann, subvar_flags);
2079 flags |= opf_no_vops;
2081 if (TREE_THIS_VOLATILE (expr))
2082 get_stmt_ann (stmt)->has_volatile_ops = true;
2084 else if (TREE_CODE (ref) == INDIRECT_REF)
2086 get_indirect_ref_operands (stmt, ref, flags, expr, offset,
2088 flags |= opf_no_vops;
2091 /* Even if we found subvars above we need to ensure to see
2092 immediate uses for d in s.a[d]. In case of s.a having
2093 a subvar or we would miss it otherwise. */
2094 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2096 if (code == COMPONENT_REF)
2098 if (s_ann && TREE_THIS_VOLATILE (TREE_OPERAND (expr, 1)))
2099 s_ann->has_volatile_ops = true;
2100 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2102 else if (code == ARRAY_REF || code == ARRAY_RANGE_REF)
2104 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2105 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2106 get_expr_operands (stmt, &TREE_OPERAND (expr, 3), opf_use);
2112 case WITH_SIZE_EXPR:
2113 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2114 and an rvalue reference to its second argument. */
2115 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2116 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2120 get_call_expr_operands (stmt, expr);
2125 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), opf_use);
2126 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), opf_use);
2127 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), opf_use);
2130 case GIMPLE_MODIFY_STMT:
2131 get_modify_stmt_operands (stmt, expr);
2136 /* General aggregate CONSTRUCTORs have been decomposed, but they
2137 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2138 constructor_elt *ce;
2139 unsigned HOST_WIDE_INT idx;
2142 VEC_iterate (constructor_elt, CONSTRUCTOR_ELTS (expr), idx, ce);
2144 get_expr_operands (stmt, &ce->value, opf_use);
2150 case TRUTH_NOT_EXPR:
2151 case VIEW_CONVERT_EXPR:
2153 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2156 case TRUTH_AND_EXPR:
2158 case TRUTH_XOR_EXPR:
2164 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2165 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2170 case REALIGN_LOAD_EXPR:
2172 get_expr_operands (stmt, &TREE_OPERAND (expr, 0), flags);
2173 get_expr_operands (stmt, &TREE_OPERAND (expr, 1), flags);
2174 get_expr_operands (stmt, &TREE_OPERAND (expr, 2), flags);
2178 case CHANGE_DYNAMIC_TYPE_EXPR:
2179 get_expr_operands (stmt, &CHANGE_DYNAMIC_TYPE_LOCATION (expr), opf_use);
2197 /* Expressions that make no memory references. */
2201 if (codeclass == tcc_unary)
2203 if (codeclass == tcc_binary || codeclass == tcc_comparison)
2205 if (codeclass == tcc_constant || codeclass == tcc_type)
2209 /* If we get here, something has gone wrong. */
2210 #ifdef ENABLE_CHECKING
2211 fprintf (stderr, "unhandled expression in get_expr_operands():\n");
2213 fputs ("\n", stderr);
2219 /* Parse STMT looking for operands. When finished, the various
2220 build_* operand vectors will have potential operands in them. */
2223 parse_ssa_operands (tree stmt)
2225 enum tree_code code;
2227 code = TREE_CODE (stmt);
2230 case GIMPLE_MODIFY_STMT:
2231 get_modify_stmt_operands (stmt, stmt);
2235 get_expr_operands (stmt, &COND_EXPR_COND (stmt), opf_use);
2239 get_expr_operands (stmt, &SWITCH_COND (stmt), opf_use);
2243 get_asm_expr_operands (stmt);
2247 get_expr_operands (stmt, &TREE_OPERAND (stmt, 0), opf_use);
2251 get_expr_operands (stmt, &GOTO_DESTINATION (stmt), opf_use);
2255 get_expr_operands (stmt, &LABEL_EXPR_LABEL (stmt), opf_use);
2259 case CASE_LABEL_EXPR:
2260 case TRY_CATCH_EXPR:
2261 case TRY_FINALLY_EXPR:
2262 case EH_FILTER_EXPR:
2265 /* These nodes contain no variable references. */
2269 /* Notice that if get_expr_operands tries to use &STMT as the
2270 operand pointer (which may only happen for USE operands), we
2271 will fail in add_stmt_operand. This default will handle
2272 statements like empty statements, or CALL_EXPRs that may
2273 appear on the RHS of a statement or as statements themselves. */
2274 get_expr_operands (stmt, &stmt, opf_use);
2280 /* Create an operands cache for STMT. */
2283 build_ssa_operands (tree stmt)
2285 stmt_ann_t ann = get_stmt_ann (stmt);
2287 /* Initially assume that the statement has no volatile operands and
2288 makes no memory references. */
2289 ann->has_volatile_ops = false;
2290 ann->references_memory = false;
2291 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2292 if (ann->addresses_taken)
2293 bitmap_clear (ann->addresses_taken);
2295 start_ssa_stmt_operands ();
2296 parse_ssa_operands (stmt);
2297 operand_build_sort_virtual (build_vuses);
2298 operand_build_sort_virtual (build_vdefs);
2299 finalize_ssa_stmt_operands (stmt);
2301 if (ann->addresses_taken && bitmap_empty_p (ann->addresses_taken))
2302 ann->addresses_taken = NULL;
2303 /* For added safety, assume that statements with volatile operands
2304 also reference memory. */
2305 if (ann->has_volatile_ops)
2306 ann->references_memory = true;
2310 /* Free any operands vectors in OPS. */
2313 free_ssa_operands (stmt_operands_p ops)
2315 ops->def_ops = NULL;
2316 ops->use_ops = NULL;
2317 ops->vdef_ops = NULL;
2318 ops->vuse_ops = NULL;
2319 BITMAP_FREE (ops->loads);
2320 BITMAP_FREE (ops->stores);
2324 /* Get the operands of statement STMT. */
2327 update_stmt_operands (tree stmt)
2329 stmt_ann_t ann = get_stmt_ann (stmt);
2331 /* If update_stmt_operands is called before SSA is initialized, do
2333 if (!ssa_operands_active ())
2336 /* The optimizers cannot handle statements that are nothing but a
2337 _DECL. This indicates a bug in the gimplifier. */
2338 gcc_assert (!SSA_VAR_P (stmt));
2340 timevar_push (TV_TREE_OPS);
2342 gcc_assert (ann->modified);
2343 build_ssa_operands (stmt);
2346 timevar_pop (TV_TREE_OPS);
2350 /* Copies virtual operands from SRC to DST. */
2353 copy_virtual_operands (tree dest, tree src)
2356 voptype_p src_vuses, dest_vuses;
2357 voptype_p src_vdefs, dest_vdefs;
2358 struct voptype_d vuse;
2359 struct voptype_d vdef;
2360 stmt_ann_t dest_ann;
2362 VDEF_OPS (dest) = NULL;
2363 VUSE_OPS (dest) = NULL;
2365 dest_ann = get_stmt_ann (dest);
2366 BITMAP_FREE (dest_ann->operands.loads);
2367 BITMAP_FREE (dest_ann->operands.stores);
2369 if (LOADED_SYMS (src))
2371 dest_ann->operands.loads = BITMAP_ALLOC (&operands_bitmap_obstack);
2372 bitmap_copy (dest_ann->operands.loads, LOADED_SYMS (src));
2375 if (STORED_SYMS (src))
2377 dest_ann->operands.stores = BITMAP_ALLOC (&operands_bitmap_obstack);
2378 bitmap_copy (dest_ann->operands.stores, STORED_SYMS (src));
2381 /* Copy all the VUSE operators and corresponding operands. */
2383 for (src_vuses = VUSE_OPS (src); src_vuses; src_vuses = src_vuses->next)
2385 n = VUSE_NUM (src_vuses);
2386 dest_vuses = add_vuse_op (dest, NULL_TREE, n, dest_vuses);
2387 for (i = 0; i < n; i++)
2388 SET_USE (VUSE_OP_PTR (dest_vuses, i), VUSE_OP (src_vuses, i));
2390 if (VUSE_OPS (dest) == NULL)
2391 VUSE_OPS (dest) = vuse.next;
2394 /* Copy all the VDEF operators and corresponding operands. */
2396 for (src_vdefs = VDEF_OPS (src); src_vdefs; src_vdefs = src_vdefs->next)
2398 n = VUSE_NUM (src_vdefs);
2399 dest_vdefs = add_vdef_op (dest, NULL_TREE, n, dest_vdefs);
2400 VDEF_RESULT (dest_vdefs) = VDEF_RESULT (src_vdefs);
2401 for (i = 0; i < n; i++)
2402 SET_USE (VUSE_OP_PTR (dest_vdefs, i), VUSE_OP (src_vdefs, i));
2404 if (VDEF_OPS (dest) == NULL)
2405 VDEF_OPS (dest) = vdef.next;
2410 /* Specifically for use in DOM's expression analysis. Given a store, we
2411 create an artificial stmt which looks like a load from the store, this can
2412 be used to eliminate redundant loads. OLD_OPS are the operands from the
2413 store stmt, and NEW_STMT is the new load which represents a load of the
2417 create_ssa_artificial_load_stmt (tree new_stmt, tree old_stmt)
2421 use_operand_p use_p;
2424 get_stmt_ann (new_stmt);
2426 /* Process NEW_STMT looking for operands. */
2427 start_ssa_stmt_operands ();
2428 parse_ssa_operands (new_stmt);
2430 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2431 if (TREE_CODE (op) != SSA_NAME)
2432 var_ann (op)->in_vuse_list = false;
2434 for (i = 0; VEC_iterate (tree, build_vuses, i, op); i++)
2435 if (TREE_CODE (op) != SSA_NAME)
2436 var_ann (op)->in_vdef_list = false;
2438 /* Remove any virtual operands that were found. */
2439 VEC_truncate (tree, build_vdefs, 0);
2440 VEC_truncate (tree, build_vuses, 0);
2442 /* For each VDEF on the original statement, we want to create a
2443 VUSE of the VDEF result operand on the new statement. */
2444 FOR_EACH_SSA_TREE_OPERAND (op, old_stmt, iter, SSA_OP_VDEF)
2447 finalize_ssa_stmt_operands (new_stmt);
2449 /* All uses in this fake stmt must not be in the immediate use lists. */
2450 FOR_EACH_SSA_USE_OPERAND (use_p, new_stmt, iter, SSA_OP_ALL_USES)
2451 delink_imm_use (use_p);
2455 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2456 to test the validity of the swap operation. */
2459 swap_tree_operands (tree stmt, tree *exp0, tree *exp1)
2465 /* If the operand cache is active, attempt to preserve the relative
2466 positions of these two operands in their respective immediate use
2468 if (ssa_operands_active () && op0 != op1)
2470 use_optype_p use0, use1, ptr;
2473 /* Find the 2 operands in the cache, if they are there. */
2474 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2475 if (USE_OP_PTR (ptr)->use == exp0)
2481 for (ptr = USE_OPS (stmt); ptr; ptr = ptr->next)
2482 if (USE_OP_PTR (ptr)->use == exp1)
2488 /* If both uses don't have operand entries, there isn't much we can do
2489 at this point. Presumably we don't need to worry about it. */
2492 tree *tmp = USE_OP_PTR (use1)->use;
2493 USE_OP_PTR (use1)->use = USE_OP_PTR (use0)->use;
2494 USE_OP_PTR (use0)->use = tmp;
2498 /* Now swap the data. */
2504 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2505 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2506 a single variable whose address has been taken or any other valid
2507 GIMPLE memory reference (structure reference, array, etc). If the
2508 base address of REF is a decl that has sub-variables, also add all
2509 of its sub-variables. */
2512 add_to_addressable_set (tree ref, bitmap *addresses_taken)
2517 gcc_assert (addresses_taken);
2519 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2520 as the only thing we take the address of. If VAR is a structure,
2521 taking the address of a field means that the whole structure may
2522 be referenced using pointer arithmetic. See PR 21407 and the
2523 ensuing mailing list discussion. */
2524 var = get_base_address (ref);
2525 if (var && SSA_VAR_P (var))
2527 if (*addresses_taken == NULL)
2528 *addresses_taken = BITMAP_GGC_ALLOC ();
2530 if (var_can_have_subvars (var)
2531 && (svars = get_subvars_for_var (var)))
2534 for (sv = svars; sv; sv = sv->next)
2536 bitmap_set_bit (*addresses_taken, DECL_UID (sv->var));
2537 TREE_ADDRESSABLE (sv->var) = 1;
2542 bitmap_set_bit (*addresses_taken, DECL_UID (var));
2543 TREE_ADDRESSABLE (var) = 1;
2549 /* Scan the immediate_use list for VAR making sure its linked properly.
2550 Return TRUE if there is a problem and emit an error message to F. */
2553 verify_imm_links (FILE *f, tree var)
2555 use_operand_p ptr, prev, list;
2558 gcc_assert (TREE_CODE (var) == SSA_NAME);
2560 list = &(SSA_NAME_IMM_USE_NODE (var));
2561 gcc_assert (list->use == NULL);
2563 if (list->prev == NULL)
2565 gcc_assert (list->next == NULL);
2571 for (ptr = list->next; ptr != list; )
2573 if (prev != ptr->prev)
2576 if (ptr->use == NULL)
2577 goto error; /* 2 roots, or SAFE guard node. */
2578 else if (*(ptr->use) != var)
2584 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2586 if (count++ > 50000000)
2590 /* Verify list in the other direction. */
2592 for (ptr = list->prev; ptr != list; )
2594 if (prev != ptr->next)
2608 if (ptr->stmt && stmt_modified_p (ptr->stmt))
2610 fprintf (f, " STMT MODIFIED. - <%p> ", (void *)ptr->stmt);
2611 print_generic_stmt (f, ptr->stmt, TDF_SLIM);
2613 fprintf (f, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr,
2615 print_generic_expr (f, USE_FROM_PTR (ptr), TDF_SLIM);
2621 /* Dump all the immediate uses to FILE. */
2624 dump_immediate_uses_for (FILE *file, tree var)
2626 imm_use_iterator iter;
2627 use_operand_p use_p;
2629 gcc_assert (var && TREE_CODE (var) == SSA_NAME);
2631 print_generic_expr (file, var, TDF_SLIM);
2632 fprintf (file, " : -->");
2633 if (has_zero_uses (var))
2634 fprintf (file, " no uses.\n");
2636 if (has_single_use (var))
2637 fprintf (file, " single use.\n");
2639 fprintf (file, "%d uses.\n", num_imm_uses (var));
2641 FOR_EACH_IMM_USE_FAST (use_p, iter, var)
2643 if (use_p->stmt == NULL && use_p->use == NULL)
2644 fprintf (file, "***end of stmt iterator marker***\n");
2646 if (!is_gimple_reg (USE_FROM_PTR (use_p)))
2647 print_generic_stmt (file, USE_STMT (use_p), TDF_VOPS|TDF_MEMSYMS);
2649 print_generic_stmt (file, USE_STMT (use_p), TDF_SLIM);
2651 fprintf(file, "\n");
2655 /* Dump all the immediate uses to FILE. */
2658 dump_immediate_uses (FILE *file)
2663 fprintf (file, "Immediate_uses: \n\n");
2664 for (x = 1; x < num_ssa_names; x++)
2669 dump_immediate_uses_for (file, var);
2674 /* Dump def-use edges on stderr. */
2677 debug_immediate_uses (void)
2679 dump_immediate_uses (stderr);
2683 /* Dump def-use edges on stderr. */
2686 debug_immediate_uses_for (tree var)
2688 dump_immediate_uses_for (stderr, var);
2692 /* Create a new change buffer for the statement pointed by STMT_P and
2693 push the buffer into SCB_STACK. Each change buffer
2694 records state information needed to determine what changed in the
2695 statement. Mainly, this keeps track of symbols that may need to be
2696 put into SSA form, SSA name replacements and other information
2697 needed to keep the SSA form up to date. */
2700 push_stmt_changes (tree *stmt_p)
2707 /* It makes no sense to keep track of PHI nodes. */
2708 if (TREE_CODE (stmt) == PHI_NODE)
2711 buf = XNEW (struct scb_d);
2712 memset (buf, 0, sizeof *buf);
2714 buf->stmt_p = stmt_p;
2716 if (stmt_references_memory_p (stmt))
2721 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2723 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2724 if (buf->loads == NULL)
2725 buf->loads = BITMAP_ALLOC (NULL);
2726 bitmap_set_bit (buf->loads, DECL_UID (sym));
2729 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2731 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2732 if (buf->stores == NULL)
2733 buf->stores = BITMAP_ALLOC (NULL);
2734 bitmap_set_bit (buf->stores, DECL_UID (sym));
2738 VEC_safe_push (scb_t, heap, scb_stack, buf);
2742 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2743 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2746 mark_difference_for_renaming (bitmap s1, bitmap s2)
2748 if (s1 == NULL && s2 == NULL)
2751 if (s1 && s2 == NULL)
2752 mark_set_for_renaming (s1);
2753 else if (s1 == NULL && s2)
2754 mark_set_for_renaming (s2);
2755 else if (!bitmap_equal_p (s1, s2))
2757 bitmap t1 = BITMAP_ALLOC (NULL);
2758 bitmap t2 = BITMAP_ALLOC (NULL);
2760 bitmap_and_compl (t1, s1, s2);
2761 bitmap_and_compl (t2, s2, s1);
2762 bitmap_ior_into (t1, t2);
2763 mark_set_for_renaming (t1);
2771 /* Pop the top SCB from SCB_STACK and act on the differences between
2772 what was recorded by push_stmt_changes and the current state of
2776 pop_stmt_changes (tree *stmt_p)
2780 bitmap loads, stores;
2785 /* It makes no sense to keep track of PHI nodes. */
2786 if (TREE_CODE (stmt) == PHI_NODE)
2789 buf = VEC_pop (scb_t, scb_stack);
2790 gcc_assert (stmt_p == buf->stmt_p);
2792 /* Force an operand re-scan on the statement and mark any newly
2793 exposed variables. */
2796 /* Determine whether any memory symbols need to be renamed. If the
2797 sets of loads and stores are different after the statement is
2798 modified, then the affected symbols need to be renamed.
2800 Note that it may be possible for the statement to not reference
2801 memory anymore, but we still need to act on the differences in
2802 the sets of symbols. */
2803 loads = stores = NULL;
2804 if (stmt_references_memory_p (stmt))
2809 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VUSE)
2811 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2813 loads = BITMAP_ALLOC (NULL);
2814 bitmap_set_bit (loads, DECL_UID (sym));
2817 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_VDEF)
2819 tree sym = TREE_CODE (op) == SSA_NAME ? SSA_NAME_VAR (op) : op;
2821 stores = BITMAP_ALLOC (NULL);
2822 bitmap_set_bit (stores, DECL_UID (sym));
2826 /* If LOADS is different from BUF->LOADS, the affected
2827 symbols need to be marked for renaming. */
2828 mark_difference_for_renaming (loads, buf->loads);
2830 /* Similarly for STORES and BUF->STORES. */
2831 mark_difference_for_renaming (stores, buf->stores);
2833 /* Mark all the naked GIMPLE register operands for renaming. */
2834 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF|SSA_OP_USE)
2836 mark_sym_for_renaming (op);
2838 /* FIXME, need to add more finalizers here. Cleanup EH info,
2839 recompute invariants for address expressions, add
2840 SSA replacement mappings, etc. For instance, given
2841 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2844 # SMT.4_20 = VDEF <SMT.4_16>
2847 So, the VDEF will disappear, but instead of marking SMT.4 for
2848 renaming it would be far more efficient to establish a
2849 replacement mapping that would replace every reference of
2850 SMT.4_20 with SMT.4_16. */
2852 /* Free memory used by the buffer. */
2853 BITMAP_FREE (buf->loads);
2854 BITMAP_FREE (buf->stores);
2855 BITMAP_FREE (loads);
2856 BITMAP_FREE (stores);
2862 /* Discard the topmost change buffer from SCB_STACK. This is useful
2863 when the caller realized that it did not actually modified the
2864 statement. It avoids the expensive operand re-scan. */
2867 discard_stmt_changes (tree *stmt_p)
2872 /* It makes no sense to keep track of PHI nodes. */
2874 if (TREE_CODE (stmt) == PHI_NODE)
2877 buf = VEC_pop (scb_t, scb_stack);
2878 gcc_assert (stmt_p == buf->stmt_p);
2880 /* Free memory used by the buffer. */
2881 BITMAP_FREE (buf->loads);
2882 BITMAP_FREE (buf->stores);
2888 /* Returns true if statement STMT may access memory. */
2891 stmt_references_memory_p (tree stmt)
2893 if (!gimple_ssa_operands (cfun)->ops_active || TREE_CODE (stmt) == PHI_NODE)
2896 return stmt_ann (stmt)->references_memory;