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 (const_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 const_tree
const e1
= *((const_tree
const *)p
);
217 const_tree
const e2
= *((const_tree
const *)q
);
218 const unsigned int u1
= get_name_decl (e1
);
219 const unsigned int u2
= get_name_decl (e2
);
221 /* We want to sort in ascending order. They can never be equal. */
222 #ifdef ENABLE_CHECKING
223 gcc_assert (u1
!= u2
);
225 return (u1
> u2
? 1 : -1);
229 /* Sort the virtual operands in LIST from lowest DECL_UID to highest. */
232 operand_build_sort_virtual (VEC(tree
,heap
) *list
)
234 int num
= VEC_length (tree
, list
);
241 if (get_name_decl (VEC_index (tree
, list
, 0))
242 > get_name_decl (VEC_index (tree
, list
, 1)))
244 /* Swap elements if in the wrong order. */
245 tree tmp
= VEC_index (tree
, list
, 0);
246 VEC_replace (tree
, list
, 0, VEC_index (tree
, list
, 1));
247 VEC_replace (tree
, list
, 1, tmp
);
252 /* There are 3 or more elements, call qsort. */
253 qsort (VEC_address (tree
, list
),
254 VEC_length (tree
, list
),
260 /* Return true if the SSA operands cache is active. */
263 ssa_operands_active (void)
265 return cfun
->gimple_df
&& gimple_ssa_operands (cfun
)->ops_active
;
269 /* VOPs are of variable sized, so the free list maps "free buckets" to the
282 Any VOPs larger than this are simply added to the largest bucket when they
286 /* Return the number of operands used in bucket BUCKET. */
289 vop_free_bucket_size (int bucket
)
291 #ifdef ENABLE_CHECKING
292 gcc_assert (bucket
>= 0 && bucket
< NUM_VOP_FREE_BUCKETS
);
296 return (bucket
- 13) * 8;
300 /* For a vop of NUM operands, return the bucket NUM belongs to. If NUM is
301 beyond the end of the bucket table, return -1. */
304 vop_free_bucket_index (int num
)
306 gcc_assert (num
> 0 && NUM_VOP_FREE_BUCKETS
> 16);
308 /* Sizes 1 through 16 use buckets 0-15. */
311 /* Buckets 16 - NUM_VOP_FREE_BUCKETS represent 8 unit chunks. */
312 num
= 14 + (num
- 1) / 8;
313 if (num
>= NUM_VOP_FREE_BUCKETS
)
320 /* Initialize the VOP free buckets. */
323 init_vop_buckets (void)
327 for (x
= 0; x
< NUM_VOP_FREE_BUCKETS
; x
++)
328 gimple_ssa_operands (cfun
)->vop_free_buckets
[x
] = NULL
;
332 /* Add PTR to the appropriate VOP bucket. */
335 add_vop_to_freelist (voptype_p ptr
)
337 int bucket
= vop_free_bucket_index (VUSE_VECT_NUM_ELEM (ptr
->usev
));
339 /* Too large, use the largest bucket so its not a complete throw away. */
341 bucket
= NUM_VOP_FREE_BUCKETS
- 1;
343 ptr
->next
= gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
];
344 gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
] = ptr
;
348 /* These are the sizes of the operand memory buffer which gets allocated each
349 time more operands space is required. The final value is the amount that is
350 allocated every time after that. */
352 #define OP_SIZE_INIT 0
354 #define OP_SIZE_2 110
355 #define OP_SIZE_3 511
357 /* Initialize the operand cache routines. */
360 init_ssa_operands (void)
362 if (!n_initialized
++)
364 build_defs
= VEC_alloc (tree
, heap
, 5);
365 build_uses
= VEC_alloc (tree
, heap
, 10);
366 build_vuses
= VEC_alloc (tree
, heap
, 25);
367 build_vdefs
= VEC_alloc (tree
, heap
, 25);
368 bitmap_obstack_initialize (&operands_bitmap_obstack
);
369 build_loads
= BITMAP_ALLOC (&operands_bitmap_obstack
);
370 build_stores
= BITMAP_ALLOC (&operands_bitmap_obstack
);
371 scb_stack
= VEC_alloc (scb_t
, heap
, 20);
374 gcc_assert (gimple_ssa_operands (cfun
)->operand_memory
== NULL
);
375 gcc_assert (gimple_ssa_operands (cfun
)->mpt_table
== NULL
);
376 gimple_ssa_operands (cfun
)->operand_memory_index
377 = gimple_ssa_operands (cfun
)->ssa_operand_mem_size
;
378 gimple_ssa_operands (cfun
)->ops_active
= true;
379 memset (&clobber_stats
, 0, sizeof (clobber_stats
));
381 gimple_ssa_operands (cfun
)->ssa_operand_mem_size
= OP_SIZE_INIT
;
385 /* Dispose of anything required by the operand routines. */
388 fini_ssa_operands (void)
390 struct ssa_operand_memory_d
*ptr
;
394 if (!--n_initialized
)
396 VEC_free (tree
, heap
, build_defs
);
397 VEC_free (tree
, heap
, build_uses
);
398 VEC_free (tree
, heap
, build_vdefs
);
399 VEC_free (tree
, heap
, build_vuses
);
400 BITMAP_FREE (build_loads
);
401 BITMAP_FREE (build_stores
);
403 /* The change buffer stack had better be empty. */
404 gcc_assert (VEC_length (scb_t
, scb_stack
) == 0);
405 VEC_free (scb_t
, heap
, scb_stack
);
409 gimple_ssa_operands (cfun
)->free_defs
= NULL
;
410 gimple_ssa_operands (cfun
)->free_uses
= NULL
;
412 while ((ptr
= gimple_ssa_operands (cfun
)->operand_memory
) != NULL
)
414 gimple_ssa_operands (cfun
)->operand_memory
415 = gimple_ssa_operands (cfun
)->operand_memory
->next
;
420 VEC_iterate (tree
, gimple_ssa_operands (cfun
)->mpt_table
, ix
, mpt
);
424 BITMAP_FREE (MPT_SYMBOLS (mpt
));
427 VEC_free (tree
, heap
, gimple_ssa_operands (cfun
)->mpt_table
);
429 gimple_ssa_operands (cfun
)->ops_active
= false;
432 bitmap_obstack_release (&operands_bitmap_obstack
);
433 if (dump_file
&& (dump_flags
& TDF_STATS
))
435 fprintf (dump_file
, "Original clobbered vars: %d\n",
436 clobber_stats
.clobbered_vars
);
437 fprintf (dump_file
, "Static write clobbers avoided: %d\n",
438 clobber_stats
.static_write_clobbers_avoided
);
439 fprintf (dump_file
, "Static read clobbers avoided: %d\n",
440 clobber_stats
.static_read_clobbers_avoided
);
441 fprintf (dump_file
, "Unescapable clobbers avoided: %d\n",
442 clobber_stats
.unescapable_clobbers_avoided
);
443 fprintf (dump_file
, "Original read-only clobbers: %d\n",
444 clobber_stats
.readonly_clobbers
);
445 fprintf (dump_file
, "Static read-only clobbers avoided: %d\n",
446 clobber_stats
.static_readonly_clobbers_avoided
);
451 /* Return memory for operands of SIZE chunks. */
454 ssa_operand_alloc (unsigned size
)
458 if (gimple_ssa_operands (cfun
)->operand_memory_index
+ size
459 >= gimple_ssa_operands (cfun
)->ssa_operand_mem_size
)
461 struct ssa_operand_memory_d
*ptr
;
463 if (gimple_ssa_operands (cfun
)->ssa_operand_mem_size
== OP_SIZE_INIT
)
464 gimple_ssa_operands (cfun
)->ssa_operand_mem_size
465 = OP_SIZE_1
* sizeof (struct voptype_d
);
467 if (gimple_ssa_operands (cfun
)->ssa_operand_mem_size
468 == OP_SIZE_1
* sizeof (struct voptype_d
))
469 gimple_ssa_operands (cfun
)->ssa_operand_mem_size
470 = OP_SIZE_2
* sizeof (struct voptype_d
);
472 gimple_ssa_operands (cfun
)->ssa_operand_mem_size
473 = OP_SIZE_3
* sizeof (struct voptype_d
);
475 /* Go right to the maximum size if the request is too large. */
476 if (size
> gimple_ssa_operands (cfun
)->ssa_operand_mem_size
)
477 gimple_ssa_operands (cfun
)->ssa_operand_mem_size
478 = OP_SIZE_3
* sizeof (struct voptype_d
);
480 /* Fail if there is not enough space. If there are this many operands
481 required, first make sure there isn't a different problem causing this
482 many operands. If the decision is that this is OK, then we can
483 specially allocate a buffer just for this request. */
484 gcc_assert (size
<= gimple_ssa_operands (cfun
)->ssa_operand_mem_size
);
486 ptr
= (struct ssa_operand_memory_d
*)
487 ggc_alloc (sizeof (struct ssa_operand_memory_d
)
488 + gimple_ssa_operands (cfun
)->ssa_operand_mem_size
- 1);
489 ptr
->next
= gimple_ssa_operands (cfun
)->operand_memory
;
490 gimple_ssa_operands (cfun
)->operand_memory
= ptr
;
491 gimple_ssa_operands (cfun
)->operand_memory_index
= 0;
493 ptr
= &(gimple_ssa_operands (cfun
)->operand_memory
494 ->mem
[gimple_ssa_operands (cfun
)->operand_memory_index
]);
495 gimple_ssa_operands (cfun
)->operand_memory_index
+= size
;
500 /* Allocate a DEF operand. */
502 static inline struct def_optype_d
*
505 struct def_optype_d
*ret
;
506 if (gimple_ssa_operands (cfun
)->free_defs
)
508 ret
= gimple_ssa_operands (cfun
)->free_defs
;
509 gimple_ssa_operands (cfun
)->free_defs
510 = gimple_ssa_operands (cfun
)->free_defs
->next
;
513 ret
= (struct def_optype_d
*)
514 ssa_operand_alloc (sizeof (struct def_optype_d
));
519 /* Allocate a USE operand. */
521 static inline struct use_optype_d
*
524 struct use_optype_d
*ret
;
525 if (gimple_ssa_operands (cfun
)->free_uses
)
527 ret
= gimple_ssa_operands (cfun
)->free_uses
;
528 gimple_ssa_operands (cfun
)->free_uses
529 = gimple_ssa_operands (cfun
)->free_uses
->next
;
532 ret
= (struct use_optype_d
*)
533 ssa_operand_alloc (sizeof (struct use_optype_d
));
538 /* Allocate a vop with NUM elements. */
540 static inline struct voptype_d
*
543 struct voptype_d
*ret
= NULL
;
546 int bucket
= vop_free_bucket_index (num
);
549 /* If there is a free operand, use it. */
550 if (gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
] != NULL
)
552 ret
= gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
];
553 gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
] =
554 gimple_ssa_operands (cfun
)->vop_free_buckets
[bucket
]->next
;
557 alloc_size
= vop_free_bucket_size(bucket
);
563 ret
= (struct voptype_d
*)ssa_operand_alloc (
564 sizeof (struct voptype_d
) + (alloc_size
- 1) * sizeof (vuse_element_t
));
566 VUSE_VECT_NUM_ELEM (ret
->usev
) = num
;
571 /* This routine makes sure that PTR is in an immediate use list, and makes
572 sure the stmt pointer is set to the current stmt. */
575 set_virtual_use_link (use_operand_p ptr
, tree stmt
)
577 /* fold_stmt may have changed the stmt pointers. */
578 if (ptr
->stmt
!= stmt
)
581 /* If this use isn't in a list, add it to the correct list. */
583 link_imm_use (ptr
, *(ptr
->use
));
587 /* Adds OP to the list of defs after LAST. */
589 static inline def_optype_p
590 add_def_op (tree
*op
, def_optype_p last
)
592 def_optype_p new_def
;
594 new_def
= alloc_def ();
595 DEF_OP_PTR (new_def
) = op
;
596 last
->next
= new_def
;
597 new_def
->next
= NULL
;
602 /* Adds OP to the list of uses of statement STMT after LAST. */
604 static inline use_optype_p
605 add_use_op (tree stmt
, tree
*op
, use_optype_p last
)
607 use_optype_p new_use
;
609 new_use
= alloc_use ();
610 USE_OP_PTR (new_use
)->use
= op
;
611 link_imm_use_stmt (USE_OP_PTR (new_use
), *op
, stmt
);
612 last
->next
= new_use
;
613 new_use
->next
= NULL
;
618 /* Return a virtual op pointer with NUM elements which are all initialized to OP
619 and are linked into the immediate uses for STMT. The new vop is appended
622 static inline voptype_p
623 add_vop (tree stmt
, tree op
, int num
, voptype_p prev
)
628 new_vop
= alloc_vop (num
);
629 for (x
= 0; x
< num
; x
++)
631 VUSE_OP_PTR (new_vop
, x
)->prev
= NULL
;
632 SET_VUSE_OP (new_vop
, x
, op
);
633 VUSE_OP_PTR (new_vop
, x
)->use
= &new_vop
->usev
.uses
[x
].use_var
;
634 link_imm_use_stmt (VUSE_OP_PTR (new_vop
, x
),
635 new_vop
->usev
.uses
[x
].use_var
, stmt
);
639 prev
->next
= new_vop
;
640 new_vop
->next
= NULL
;
645 /* Adds OP to the list of vuses of statement STMT after LAST, and moves
646 LAST to the new element. */
648 static inline voptype_p
649 add_vuse_op (tree stmt
, tree op
, int num
, voptype_p last
)
651 voptype_p new_vop
= add_vop (stmt
, op
, num
, last
);
652 VDEF_RESULT (new_vop
) = NULL_TREE
;
657 /* Adds OP to the list of vdefs of statement STMT after LAST, and moves
658 LAST to the new element. */
660 static inline voptype_p
661 add_vdef_op (tree stmt
, tree op
, int num
, voptype_p last
)
663 voptype_p new_vop
= add_vop (stmt
, op
, num
, last
);
664 VDEF_RESULT (new_vop
) = op
;
669 /* Takes elements from build_defs and turns them into def operands of STMT.
670 TODO -- Make build_defs VEC of tree *. */
673 finalize_ssa_defs (tree stmt
)
676 struct def_optype_d new_list
;
677 def_optype_p old_ops
, last
;
678 unsigned int num
= VEC_length (tree
, build_defs
);
680 /* There should only be a single real definition per assignment. */
681 gcc_assert ((stmt
&& TREE_CODE (stmt
) != GIMPLE_MODIFY_STMT
) || num
<= 1);
683 new_list
.next
= NULL
;
686 old_ops
= DEF_OPS (stmt
);
690 /* Check for the common case of 1 def that hasn't changed. */
691 if (old_ops
&& old_ops
->next
== NULL
&& num
== 1
692 && (tree
*) VEC_index (tree
, build_defs
, 0) == DEF_OP_PTR (old_ops
))
695 /* If there is anything in the old list, free it. */
698 old_ops
->next
= gimple_ssa_operands (cfun
)->free_defs
;
699 gimple_ssa_operands (cfun
)->free_defs
= old_ops
;
702 /* If there is anything remaining in the build_defs list, simply emit it. */
703 for ( ; new_i
< num
; new_i
++)
704 last
= add_def_op ((tree
*) VEC_index (tree
, build_defs
, new_i
), last
);
706 /* Now set the stmt's operands. */
707 DEF_OPS (stmt
) = new_list
.next
;
709 #ifdef ENABLE_CHECKING
713 for (ptr
= DEF_OPS (stmt
); ptr
; ptr
= ptr
->next
)
716 gcc_assert (x
== num
);
722 /* Takes elements from build_uses and turns them into use operands of STMT.
723 TODO -- Make build_uses VEC of tree *. */
726 finalize_ssa_uses (tree stmt
)
729 struct use_optype_d new_list
;
730 use_optype_p old_ops
, ptr
, last
;
732 #ifdef ENABLE_CHECKING
735 unsigned num
= VEC_length (tree
, build_uses
);
737 /* If the pointer to the operand is the statement itself, something is
738 wrong. It means that we are pointing to a local variable (the
739 initial call to update_stmt_operands does not pass a pointer to a
741 for (x
= 0; x
< num
; x
++)
742 gcc_assert (*((tree
*)VEC_index (tree
, build_uses
, x
)) != stmt
);
746 new_list
.next
= NULL
;
749 old_ops
= USE_OPS (stmt
);
751 /* If there is anything in the old list, free it. */
754 for (ptr
= old_ops
; ptr
; ptr
= ptr
->next
)
755 delink_imm_use (USE_OP_PTR (ptr
));
756 old_ops
->next
= gimple_ssa_operands (cfun
)->free_uses
;
757 gimple_ssa_operands (cfun
)->free_uses
= old_ops
;
760 /* Now create nodes for all the new nodes. */
761 for (new_i
= 0; new_i
< VEC_length (tree
, build_uses
); new_i
++)
762 last
= add_use_op (stmt
,
763 (tree
*) VEC_index (tree
, build_uses
, new_i
),
766 /* Now set the stmt's operands. */
767 USE_OPS (stmt
) = new_list
.next
;
769 #ifdef ENABLE_CHECKING
772 for (ptr
= USE_OPS (stmt
); ptr
; ptr
= ptr
->next
)
775 gcc_assert (x
== VEC_length (tree
, build_uses
));
781 /* Takes elements from BUILD_VDEFS and turns them into vdef operands of
782 STMT. FIXME, for now VDEF operators should have a single operand
786 finalize_ssa_vdefs (tree stmt
)
789 struct voptype_d new_list
;
790 voptype_p old_ops
, ptr
, last
;
791 stmt_ann_t ann
= stmt_ann (stmt
);
793 /* Set the symbols referenced by STMT. */
794 if (!bitmap_empty_p (build_stores
))
796 if (ann
->operands
.stores
== NULL
)
797 ann
->operands
.stores
= BITMAP_ALLOC (&operands_bitmap_obstack
);
799 bitmap_copy (ann
->operands
.stores
, build_stores
);
802 BITMAP_FREE (ann
->operands
.stores
);
804 /* If aliases have not been computed, do not instantiate a virtual
805 operator on STMT. Initially, we only compute the SSA form on
806 GIMPLE registers. The virtual SSA form is only computed after
807 alias analysis, so virtual operators will remain unrenamed and
808 the verifier will complain. However, alias analysis needs to
809 access symbol load/store information, so we need to compute
811 if (!gimple_aliases_computed_p (cfun
))
814 new_list
.next
= NULL
;
817 old_ops
= VDEF_OPS (stmt
);
819 while (old_ops
&& new_i
< VEC_length (tree
, build_vdefs
))
821 tree op
= VEC_index (tree
, build_vdefs
, new_i
);
822 unsigned new_uid
= get_name_decl (op
);
823 unsigned old_uid
= get_name_decl (VDEF_RESULT (old_ops
));
825 /* FIXME, for now each VDEF operator should have at most one
826 operand in their RHS. */
827 gcc_assert (VDEF_NUM (old_ops
) == 1);
829 if (old_uid
== new_uid
)
831 /* If the symbols are the same, reuse the existing operand. */
832 last
->next
= old_ops
;
834 old_ops
= old_ops
->next
;
836 set_virtual_use_link (VDEF_OP_PTR (last
, 0), stmt
);
839 else if (old_uid
< new_uid
)
841 /* If old is less than new, old goes to the free list. */
843 delink_imm_use (VDEF_OP_PTR (old_ops
, 0));
844 next
= old_ops
->next
;
845 add_vop_to_freelist (old_ops
);
850 /* This is a new operand. */
851 last
= add_vdef_op (stmt
, op
, 1, last
);
856 /* If there is anything remaining in BUILD_VDEFS, simply emit it. */
857 for ( ; new_i
< VEC_length (tree
, build_vdefs
); new_i
++)
858 last
= add_vdef_op (stmt
, VEC_index (tree
, build_vdefs
, new_i
), 1, last
);
860 /* If there is anything in the old list, free it. */
863 for (ptr
= old_ops
; ptr
; ptr
= last
)
866 delink_imm_use (VDEF_OP_PTR (ptr
, 0));
867 add_vop_to_freelist (ptr
);
871 /* Now set STMT's operands. */
872 VDEF_OPS (stmt
) = new_list
.next
;
874 #ifdef ENABLE_CHECKING
877 for (ptr
= VDEF_OPS (stmt
); ptr
; ptr
= ptr
->next
)
880 gcc_assert (x
== VEC_length (tree
, build_vdefs
));
886 /* Takes elements from BUILD_VUSES and turns them into VUSE operands of
890 finalize_ssa_vuse_ops (tree stmt
)
892 unsigned new_i
, old_i
;
893 voptype_p old_ops
, last
;
894 VEC(tree
,heap
) *new_ops
;
897 /* Set the symbols referenced by STMT. */
898 ann
= stmt_ann (stmt
);
899 if (!bitmap_empty_p (build_loads
))
901 if (ann
->operands
.loads
== NULL
)
902 ann
->operands
.loads
= BITMAP_ALLOC (&operands_bitmap_obstack
);
904 bitmap_copy (ann
->operands
.loads
, build_loads
);
907 BITMAP_FREE (ann
->operands
.loads
);
909 /* If aliases have not been computed, do not instantiate a virtual
910 operator on STMT. Initially, we only compute the SSA form on
911 GIMPLE registers. The virtual SSA form is only computed after
912 alias analysis, so virtual operators will remain unrenamed and
913 the verifier will complain. However, alias analysis needs to
914 access symbol load/store information, so we need to compute
916 if (!gimple_aliases_computed_p (cfun
))
919 /* STMT should have at most one VUSE operator. */
920 old_ops
= VUSE_OPS (stmt
);
921 gcc_assert (old_ops
== NULL
|| old_ops
->next
== NULL
);
926 && old_i
< VUSE_NUM (old_ops
)
927 && new_i
< VEC_length (tree
, build_vuses
))
929 tree new_op
= VEC_index (tree
, build_vuses
, new_i
);
930 tree old_op
= VUSE_OP (old_ops
, old_i
);
931 unsigned new_uid
= get_name_decl (new_op
);
932 unsigned old_uid
= get_name_decl (old_op
);
934 if (old_uid
== new_uid
)
936 /* If the symbols are the same, reuse the existing operand. */
937 VEC_safe_push (tree
, heap
, new_ops
, old_op
);
941 else if (old_uid
< new_uid
)
943 /* If OLD_UID is less than NEW_UID, the old operand has
944 disappeared, skip to the next old operand. */
949 /* This is a new operand. */
950 VEC_safe_push (tree
, heap
, new_ops
, new_op
);
955 /* If there is anything remaining in the build_vuses list, simply emit it. */
956 for ( ; new_i
< VEC_length (tree
, build_vuses
); new_i
++)
957 VEC_safe_push (tree
, heap
, new_ops
, VEC_index (tree
, build_vuses
, new_i
));
959 /* If there is anything in the old list, free it. */
962 for (old_i
= 0; old_i
< VUSE_NUM (old_ops
); old_i
++)
963 delink_imm_use (VUSE_OP_PTR (old_ops
, old_i
));
964 add_vop_to_freelist (old_ops
);
965 VUSE_OPS (stmt
) = NULL
;
968 /* If there are any operands, instantiate a VUSE operator for STMT. */
974 last
= add_vuse_op (stmt
, NULL
, VEC_length (tree
, new_ops
), NULL
);
976 for (i
= 0; VEC_iterate (tree
, new_ops
, i
, op
); i
++)
977 SET_USE (VUSE_OP_PTR (last
, (int) i
), op
);
979 VUSE_OPS (stmt
) = last
;
980 VEC_free (tree
, heap
, new_ops
);
983 #ifdef ENABLE_CHECKING
989 gcc_assert (VUSE_OPS (stmt
)->next
== NULL
);
990 x
= VUSE_NUM (VUSE_OPS (stmt
));
995 gcc_assert (x
== VEC_length (tree
, build_vuses
));
1000 /* Return a new VUSE operand vector for STMT. */
1003 finalize_ssa_vuses (tree stmt
)
1005 unsigned num
, num_vdefs
;
1006 unsigned vuse_index
;
1008 /* Remove superfluous VUSE operands. If the statement already has a
1009 VDEF operator for a variable 'a', then a VUSE for 'a' is not
1010 needed because VDEFs imply a VUSE of the variable. For instance,
1011 suppose that variable 'a' is pointed-to by p and q:
1017 The VUSE <a_2> is superfluous because it is implied by the
1019 num
= VEC_length (tree
, build_vuses
);
1020 num_vdefs
= VEC_length (tree
, build_vdefs
);
1022 if (num
> 0 && num_vdefs
> 0)
1023 for (vuse_index
= 0; vuse_index
< VEC_length (tree
, build_vuses
); )
1026 vuse
= VEC_index (tree
, build_vuses
, vuse_index
);
1027 if (TREE_CODE (vuse
) != SSA_NAME
)
1029 var_ann_t ann
= var_ann (vuse
);
1030 ann
->in_vuse_list
= 0;
1031 if (ann
->in_vdef_list
)
1033 VEC_ordered_remove (tree
, build_vuses
, vuse_index
);
1040 finalize_ssa_vuse_ops (stmt
);
1044 /* Clear the in_list bits and empty the build array for VDEFs and
1048 cleanup_build_arrays (void)
1053 for (i
= 0; VEC_iterate (tree
, build_vdefs
, i
, t
); i
++)
1054 if (TREE_CODE (t
) != SSA_NAME
)
1055 var_ann (t
)->in_vdef_list
= false;
1057 for (i
= 0; VEC_iterate (tree
, build_vuses
, i
, t
); i
++)
1058 if (TREE_CODE (t
) != SSA_NAME
)
1059 var_ann (t
)->in_vuse_list
= false;
1061 VEC_truncate (tree
, build_vdefs
, 0);
1062 VEC_truncate (tree
, build_vuses
, 0);
1063 VEC_truncate (tree
, build_defs
, 0);
1064 VEC_truncate (tree
, build_uses
, 0);
1065 bitmap_clear (build_loads
);
1066 bitmap_clear (build_stores
);
1070 /* Finalize all the build vectors, fill the new ones into INFO. */
1073 finalize_ssa_stmt_operands (tree stmt
)
1075 finalize_ssa_defs (stmt
);
1076 finalize_ssa_uses (stmt
);
1077 finalize_ssa_vdefs (stmt
);
1078 finalize_ssa_vuses (stmt
);
1079 cleanup_build_arrays ();
1083 /* Start the process of building up operands vectors in INFO. */
1086 start_ssa_stmt_operands (void)
1088 gcc_assert (VEC_length (tree
, build_defs
) == 0);
1089 gcc_assert (VEC_length (tree
, build_uses
) == 0);
1090 gcc_assert (VEC_length (tree
, build_vuses
) == 0);
1091 gcc_assert (VEC_length (tree
, build_vdefs
) == 0);
1092 gcc_assert (bitmap_empty_p (build_loads
));
1093 gcc_assert (bitmap_empty_p (build_stores
));
1097 /* Add DEF_P to the list of pointers to operands. */
1100 append_def (tree
*def_p
)
1102 VEC_safe_push (tree
, heap
, build_defs
, (tree
) def_p
);
1106 /* Add USE_P to the list of pointers to operands. */
1109 append_use (tree
*use_p
)
1111 VEC_safe_push (tree
, heap
, build_uses
, (tree
) use_p
);
1115 /* Add VAR to the set of variables that require a VDEF operator. */
1118 append_vdef (tree var
)
1122 if (TREE_CODE (var
) != SSA_NAME
)
1127 /* If VAR belongs to a memory partition, use it instead of VAR. */
1128 mpt
= memory_partition (var
);
1132 /* Don't allow duplicate entries. */
1133 ann
= get_var_ann (var
);
1134 if (ann
->in_vdef_list
)
1137 ann
->in_vdef_list
= true;
1141 sym
= SSA_NAME_VAR (var
);
1143 VEC_safe_push (tree
, heap
, build_vdefs
, var
);
1144 bitmap_set_bit (build_stores
, DECL_UID (sym
));
1148 /* Add VAR to the set of variables that require a VUSE operator. */
1151 append_vuse (tree var
)
1155 if (TREE_CODE (var
) != SSA_NAME
)
1160 /* If VAR belongs to a memory partition, use it instead of VAR. */
1161 mpt
= memory_partition (var
);
1165 /* Don't allow duplicate entries. */
1166 ann
= get_var_ann (var
);
1167 if (ann
->in_vuse_list
|| ann
->in_vdef_list
)
1170 ann
->in_vuse_list
= true;
1174 sym
= SSA_NAME_VAR (var
);
1176 VEC_safe_push (tree
, heap
, build_vuses
, var
);
1177 bitmap_set_bit (build_loads
, DECL_UID (sym
));
1181 /* REF is a tree that contains the entire pointer dereference
1182 expression, if available, or NULL otherwise. ALIAS is the variable
1183 we are asking if REF can access. OFFSET and SIZE come from the
1184 memory access expression that generated this virtual operand.
1186 XXX: We should handle the NO_ALIAS attributes here. */
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 ref is a TARGET_MEM_REF, just return true, as we can't really
1203 disambiguate them right now. */
1204 if (ref
&& TREE_CODE (ref
) == TARGET_MEM_REF
)
1207 /* If ALIAS is an SFT, it can't be touched if the offset
1208 and size of the access is not overlapping with the SFT offset and
1209 size. This is only true if we are accessing through a pointer
1210 to a type that is the same as SFT_PARENT_VAR. Otherwise, we may
1211 be accessing through a pointer to some substruct of the
1212 structure, and if we try to prune there, we will have the wrong
1213 offset, and get the wrong answer.
1214 i.e., we can't prune without more work if we have something like
1220 const char *byte_op;
1228 foo = &targetm.asm_out.aligned_op;
1231 SFT.1, which represents hi, will have SFT_OFFSET=32 because in
1232 terms of SFT_PARENT_VAR, that is where it is.
1233 However, the access through the foo pointer will be at offset 0. */
1235 && TREE_CODE (alias
) == STRUCT_FIELD_TAG
1237 && TREE_TYPE (base
) == TREE_TYPE (SFT_PARENT_VAR (alias
))
1238 && !overlap_subvar (offset
, size
, alias
, NULL
))
1240 #ifdef ACCESS_DEBUGGING
1241 fprintf (stderr
, "Access to ");
1242 print_generic_expr (stderr
, ref
, 0);
1243 fprintf (stderr
, " may not touch ");
1244 print_generic_expr (stderr
, alias
, 0);
1245 fprintf (stderr
, " in function %s\n", get_name (current_function_decl
));
1250 /* Without strict aliasing, it is impossible for a component access
1251 through a pointer to touch a random variable, unless that
1252 variable *is* a structure or a pointer.
1254 That is, given p->c, and some random global variable b,
1255 there is no legal way that p->c could be an access to b.
1257 Without strict aliasing on, we consider it legal to do something
1260 struct foos { int l; };
1262 static struct foos *getfoo(void);
1265 struct foos *f = getfoo();
1272 static struct foos *getfoo(void)
1273 { return (struct foos *)&foo; }
1275 (taken from 20000623-1.c)
1277 The docs also say/imply that access through union pointers
1278 is legal (but *not* if you take the address of the union member,
1279 i.e. the inverse), such that you can do
1289 U *pretmp = (U*)&rv;
1293 To implement this, we just punt on accesses through union
1296 Another case we have to allow is accessing a variable
1297 through an array access at offset zero. This happens from
1298 code generated by the fortran frontend like
1300 char[1:1] & my_char_ref;
1302 my_char_ref_1 = (char[1:1] &) &my_char;
1303 D.874_2 = (*my_char_ref_1)[1]{lb: 1 sz: 1};
1306 && flag_strict_aliasing
1307 && TREE_CODE (ref
) != INDIRECT_REF
1310 && (TREE_CODE (base
) != INDIRECT_REF
1311 || TREE_CODE (TREE_TYPE (base
)) != UNION_TYPE
)
1312 && (TREE_CODE (base
) != INDIRECT_REF
1313 || TREE_CODE (ref
) != ARRAY_REF
1315 || (DECL_SIZE (alias
)
1316 && TREE_CODE (DECL_SIZE (alias
)) == INTEGER_CST
1318 && (unsigned HOST_WIDE_INT
)size
1319 != TREE_INT_CST_LOW (DECL_SIZE (alias
))))
1320 && !AGGREGATE_TYPE_P (TREE_TYPE (alias
))
1321 && TREE_CODE (TREE_TYPE (alias
)) != COMPLEX_TYPE
1322 && !var_ann (alias
)->is_heapvar
1323 /* When the struct has may_alias attached to it, we need not to
1325 && get_alias_set (base
))
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
));
1337 /* If the offset of the access is greater than the size of one of
1338 the possible aliases, it can't be touching that alias, because it
1339 would be past the end of the structure. */
1341 && flag_strict_aliasing
1342 && TREE_CODE (ref
) != INDIRECT_REF
1344 && !POINTER_TYPE_P (TREE_TYPE (alias
))
1346 && DECL_SIZE (alias
)
1347 && TREE_CODE (DECL_SIZE (alias
)) == INTEGER_CST
1348 && uoffset
> TREE_INT_CST_LOW (DECL_SIZE (alias
)))
1350 #ifdef ACCESS_DEBUGGING
1351 fprintf (stderr
, "Access to ");
1352 print_generic_expr (stderr
, ref
, 0);
1353 fprintf (stderr
, " may not touch ");
1354 print_generic_expr (stderr
, alias
, 0);
1355 fprintf (stderr
, " in function %s\n", get_name (current_function_decl
));
1363 /* Add the actual variables FULL_REF can access, given a member of
1364 full_ref's points-to set VAR, where FULL_REF is an access of SIZE at
1365 OFFSET from var. IS_CALL_SITE is true if this is a call, and IS_DEF
1366 is true if this is supposed to be a vdef, and false if this should
1369 The real purpose of this function is to take a points-to set for a
1370 pointer to a structure, say
1375 } foo, *foop = &foo;
1377 and discover which variables an access, such as foop->b, can alias.
1379 This is necessary because foop only actually points to foo's first
1380 member, so that is all the points-to set contains. However, an access
1381 to foop->a may be touching some single SFT if we have created some
1382 SFT's for a structure. */
1385 add_vars_for_offset (tree full_ref
, tree var
, HOST_WIDE_INT offset
,
1386 HOST_WIDE_INT size
, bool is_call_site
, bool is_def
)
1388 /* Call-clobbered tags may have non-call-clobbered
1389 symbols in their alias sets. Ignore them if we are
1390 adding VOPs for a call site. */
1391 if (is_call_site
&& !is_call_clobbered (var
))
1394 /* For offset 0, we already have the right variable. If there is no
1395 full_ref, this is not a place we care about (All component
1396 related accesses that go through pointers will have full_ref not
1398 Any var for which we didn't create SFT's can't be
1400 if (!full_ref
|| (offset
== 0 && size
!= -1)
1401 || (TREE_CODE (var
) != STRUCT_FIELD_TAG
1402 && (!var_can_have_subvars (var
) || !get_subvars_for_var (var
))))
1404 if (!access_can_touch_variable (full_ref
, var
, offset
, size
))
1413 else if (TREE_CODE (var
) == STRUCT_FIELD_TAG
)
1418 subvar_t sv
= get_subvars_for_var (SFT_PARENT_VAR (var
));
1419 for (; sv
; sv
= sv
->next
)
1421 if (overlap_subvar (SFT_OFFSET (var
) + offset
, size
,
1423 && access_can_touch_variable (full_ref
, sv
->var
,
1428 append_vdef (sv
->var
);
1430 append_vuse (sv
->var
);
1438 subvar_t sv
= get_subvars_for_var (SFT_PARENT_VAR (var
));
1439 for (; sv
; sv
= sv
->next
)
1441 /* Once we hit the end of the parts that could touch,
1443 if (SFT_OFFSET (var
) + offset
+ size
<= SFT_OFFSET (sv
->var
))
1445 if (overlap_subvar (SFT_OFFSET (var
) + offset
, size
,
1447 && access_can_touch_variable (full_ref
, sv
->var
, offset
,
1452 append_vdef (sv
->var
);
1454 append_vuse (sv
->var
);
1464 /* Add VAR to the virtual operands array. FLAGS is as in
1465 get_expr_operands. FULL_REF is a tree that contains the entire
1466 pointer dereference expression, if available, or NULL otherwise.
1467 OFFSET and SIZE come from the memory access expression that
1468 generated this virtual operand. IS_CALL_SITE is true if the
1469 affected statement is a call site. */
1472 add_virtual_operand (tree var
, stmt_ann_t s_ann
, int flags
,
1473 tree full_ref
, HOST_WIDE_INT offset
,
1474 HOST_WIDE_INT size
, bool is_call_site
)
1476 bitmap aliases
= NULL
;
1480 sym
= (TREE_CODE (var
) == SSA_NAME
? SSA_NAME_VAR (var
) : var
);
1481 v_ann
= var_ann (sym
);
1483 /* Mark the statement as having memory operands. */
1484 s_ann
->references_memory
= true;
1486 /* If the variable cannot be modified and this is a VDEF change
1487 it into a VUSE. This happens when read-only variables are marked
1488 call-clobbered and/or aliased to writable variables. So we only
1489 check that this only happens on non-specific stores.
1491 Note that if this is a specific store, i.e. associated with a
1492 GIMPLE_MODIFY_STMT, then we can't suppress the VDEF, lest we run
1493 into validation problems.
1495 This can happen when programs cast away const, leaving us with a
1496 store to read-only memory. If the statement is actually executed
1497 at runtime, then the program is ill formed. If the statement is
1498 not executed then all is well. At the very least, we cannot ICE. */
1499 if ((flags
& opf_implicit
) && unmodifiable_var_p (var
))
1502 /* The variable is not a GIMPLE register. Add it (or its aliases) to
1503 virtual operands, unless the caller has specifically requested
1504 not to add virtual operands (used when adding operands inside an
1505 ADDR_EXPR expression). */
1506 if (flags
& opf_no_vops
)
1510 aliases
= MTAG_ALIASES (var
);
1512 if (aliases
== NULL
)
1514 if (!gimple_aliases_computed_p (cfun
))
1515 s_ann
->has_volatile_ops
= true;
1517 /* The variable is not aliased or it is an alias tag. */
1518 if (flags
& opf_def
)
1529 /* The variable is aliased. Add its aliases to the virtual
1531 gcc_assert (!bitmap_empty_p (aliases
));
1533 if (flags
& opf_def
)
1535 bool none_added
= true;
1536 EXECUTE_IF_SET_IN_BITMAP (aliases
, 0, i
, bi
)
1538 al
= referenced_var (i
);
1539 none_added
&= !add_vars_for_offset (full_ref
, al
, offset
, size
,
1540 is_call_site
, true);
1543 /* If the variable is also an alias tag, add a virtual
1544 operand for it, otherwise we will miss representing
1545 references to the members of the variable's alias set.
1546 This fixes the bug in gcc.c-torture/execute/20020503-1.c.
1548 It is also necessary to add bare defs on clobbers for
1549 SMT's, so that bare SMT uses caused by pruning all the
1550 aliases will link up properly with calls. In order to
1551 keep the number of these bare defs we add down to the
1552 minimum necessary, we keep track of which SMT's were used
1553 alone in statement vdefs or VUSEs. */
1555 || (TREE_CODE (var
) == SYMBOL_MEMORY_TAG
1561 bool none_added
= true;
1562 EXECUTE_IF_SET_IN_BITMAP (aliases
, 0, i
, bi
)
1564 al
= referenced_var (i
);
1565 none_added
&= !add_vars_for_offset (full_ref
, al
, offset
, size
,
1566 is_call_site
, false);
1570 /* Even if no aliases have been added, we still need to
1571 establish def-use and use-def chains, lest
1572 transformations think that this is not a memory
1573 reference. For an example of this scenario, see
1574 testsuite/g++.dg/opt/cleanup1.C. */
1582 /* Add *VAR_P to the appropriate operand array for S_ANN. FLAGS is as in
1583 get_expr_operands. If *VAR_P is a GIMPLE register, it will be added to
1584 the statement's real operands, otherwise it is added to virtual
1588 add_stmt_operand (tree
*var_p
, stmt_ann_t s_ann
, int flags
)
1593 gcc_assert (SSA_VAR_P (*var_p
) && s_ann
);
1596 sym
= (TREE_CODE (var
) == SSA_NAME
? SSA_NAME_VAR (var
) : var
);
1597 v_ann
= var_ann (sym
);
1599 /* Mark statements with volatile operands. */
1600 if (TREE_THIS_VOLATILE (sym
))
1601 s_ann
->has_volatile_ops
= true;
1603 if (is_gimple_reg (sym
))
1605 /* The variable is a GIMPLE register. Add it to real operands. */
1606 if (flags
& opf_def
)
1612 add_virtual_operand (var
, s_ann
, flags
, NULL_TREE
, 0, -1, false);
1616 /* A subroutine of get_expr_operands to handle INDIRECT_REF,
1617 ALIGN_INDIRECT_REF and MISALIGNED_INDIRECT_REF.
1619 STMT is the statement being processed, EXPR is the INDIRECT_REF
1622 FLAGS is as in get_expr_operands.
1624 FULL_REF contains the full pointer dereference expression, if we
1625 have it, or NULL otherwise.
1627 OFFSET and SIZE are the location of the access inside the
1628 dereferenced pointer, if known.
1630 RECURSE_ON_BASE should be set to true if we want to continue
1631 calling get_expr_operands on the base pointer, and false if
1632 something else will do it for us. */
1635 get_indirect_ref_operands (tree stmt
, tree expr
, int flags
,
1637 HOST_WIDE_INT offset
, HOST_WIDE_INT size
,
1638 bool recurse_on_base
)
1640 tree
*pptr
= &TREE_OPERAND (expr
, 0);
1642 stmt_ann_t s_ann
= stmt_ann (stmt
);
1644 s_ann
->references_memory
= true;
1645 if (TREE_THIS_VOLATILE (expr
))
1646 s_ann
->has_volatile_ops
= true;
1648 if (SSA_VAR_P (ptr
))
1650 struct ptr_info_def
*pi
= NULL
;
1652 /* If PTR has flow-sensitive points-to information, use it. */
1653 if (TREE_CODE (ptr
) == SSA_NAME
1654 && (pi
= SSA_NAME_PTR_INFO (ptr
)) != NULL
1655 && pi
->name_mem_tag
)
1657 /* PTR has its own memory tag. Use it. */
1658 add_virtual_operand (pi
->name_mem_tag
, s_ann
, flags
,
1659 full_ref
, offset
, size
, false);
1663 /* If PTR is not an SSA_NAME or it doesn't have a name
1664 tag, use its symbol memory tag. */
1667 /* If we are emitting debugging dumps, display a warning if
1668 PTR is an SSA_NAME with no flow-sensitive alias
1669 information. That means that we may need to compute
1672 && TREE_CODE (ptr
) == SSA_NAME
1676 "NOTE: no flow-sensitive alias info for ");
1677 print_generic_expr (dump_file
, ptr
, dump_flags
);
1678 fprintf (dump_file
, " in ");
1679 print_generic_stmt (dump_file
, stmt
, dump_flags
);
1682 if (TREE_CODE (ptr
) == SSA_NAME
)
1683 ptr
= SSA_NAME_VAR (ptr
);
1684 v_ann
= var_ann (ptr
);
1686 if (v_ann
->symbol_mem_tag
)
1687 add_virtual_operand (v_ann
->symbol_mem_tag
, s_ann
, flags
,
1688 full_ref
, offset
, size
, false);
1690 /* Aliasing information is missing; mark statement as
1691 volatile so we won't optimize it out too actively. */
1692 else if (!gimple_aliases_computed_p (cfun
)
1693 && (flags
& opf_def
))
1694 s_ann
->has_volatile_ops
= true;
1697 else if (TREE_CODE (ptr
) == INTEGER_CST
)
1699 /* If a constant is used as a pointer, we can't generate a real
1700 operand for it but we mark the statement volatile to prevent
1701 optimizations from messing things up. */
1702 s_ann
->has_volatile_ops
= true;
1707 /* Ok, this isn't even is_gimple_min_invariant. Something's broke. */
1711 /* If requested, add a USE operand for the base pointer. */
1712 if (recurse_on_base
)
1713 get_expr_operands (stmt
, pptr
, opf_use
);
1717 /* A subroutine of get_expr_operands to handle TARGET_MEM_REF. */
1720 get_tmr_operands (tree stmt
, tree expr
, int flags
)
1723 stmt_ann_t s_ann
= stmt_ann (stmt
);
1725 /* This statement references memory. */
1726 s_ann
->references_memory
= 1;
1728 /* First record the real operands. */
1729 get_expr_operands (stmt
, &TMR_BASE (expr
), opf_use
);
1730 get_expr_operands (stmt
, &TMR_INDEX (expr
), opf_use
);
1732 if (TMR_SYMBOL (expr
))
1733 add_to_addressable_set (TMR_SYMBOL (expr
), &s_ann
->addresses_taken
);
1735 tag
= TMR_TAG (expr
);
1738 /* Something weird, so ensure that we will be careful. */
1739 s_ann
->has_volatile_ops
= true;
1744 get_expr_operands (stmt
, &tag
, flags
);
1748 add_virtual_operand (tag
, s_ann
, flags
, expr
, 0, -1, false);
1752 /* Add clobbering definitions for .GLOBAL_VAR or for each of the call
1753 clobbered variables in the function. */
1756 add_call_clobber_ops (tree stmt
, tree callee
)
1760 stmt_ann_t s_ann
= stmt_ann (stmt
);
1761 bitmap not_read_b
, not_written_b
;
1763 /* If we created .GLOBAL_VAR earlier, just use it. */
1764 if (gimple_global_var (cfun
))
1766 tree var
= gimple_global_var (cfun
);
1767 add_virtual_operand (var
, s_ann
, opf_def
, NULL
, 0, -1, true);
1771 /* Get info for local and module level statics. There is a bit
1772 set for each static if the call being processed does not read
1773 or write that variable. */
1774 not_read_b
= callee
? ipa_reference_get_not_read_global (callee
) : NULL
;
1775 not_written_b
= callee
? ipa_reference_get_not_written_global (callee
) : NULL
;
1777 /* Add a VDEF operand for every call clobbered variable. */
1778 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun
), 0, u
, bi
)
1780 tree var
= referenced_var_lookup (u
);
1781 unsigned int escape_mask
= var_ann (var
)->escape_mask
;
1782 tree real_var
= var
;
1786 /* Not read and not written are computed on regular vars, not
1787 subvars, so look at the parent var if this is an SFT. */
1788 if (TREE_CODE (var
) == STRUCT_FIELD_TAG
)
1789 real_var
= SFT_PARENT_VAR (var
);
1791 not_read
= not_read_b
1792 ? bitmap_bit_p (not_read_b
, DECL_UID (real_var
))
1795 not_written
= not_written_b
1796 ? bitmap_bit_p (not_written_b
, DECL_UID (real_var
))
1798 gcc_assert (!unmodifiable_var_p (var
));
1800 clobber_stats
.clobbered_vars
++;
1802 /* See if this variable is really clobbered by this function. */
1804 /* Trivial case: Things escaping only to pure/const are not
1805 clobbered by non-pure-const, and only read by pure/const. */
1806 if ((escape_mask
& ~(ESCAPE_TO_PURE_CONST
)) == 0)
1808 tree call
= get_call_expr_in (stmt
);
1809 if (call_expr_flags (call
) & (ECF_CONST
| ECF_PURE
))
1811 add_virtual_operand (var
, s_ann
, opf_use
, NULL
, 0, -1, true);
1812 clobber_stats
.unescapable_clobbers_avoided
++;
1817 clobber_stats
.unescapable_clobbers_avoided
++;
1824 clobber_stats
.static_write_clobbers_avoided
++;
1826 add_virtual_operand (var
, s_ann
, opf_use
, NULL
, 0, -1, true);
1828 clobber_stats
.static_read_clobbers_avoided
++;
1831 add_virtual_operand (var
, s_ann
, opf_def
, NULL
, 0, -1, true);
1836 /* Add VUSE operands for .GLOBAL_VAR or all call clobbered variables in the
1840 add_call_read_ops (tree stmt
, tree callee
)
1844 stmt_ann_t s_ann
= stmt_ann (stmt
);
1847 /* if the function is not pure, it may reference memory. Add
1848 a VUSE for .GLOBAL_VAR if it has been created. See add_referenced_var
1849 for the heuristic used to decide whether to create .GLOBAL_VAR. */
1850 if (gimple_global_var (cfun
))
1852 tree var
= gimple_global_var (cfun
);
1853 add_virtual_operand (var
, s_ann
, opf_use
, NULL
, 0, -1, true);
1857 not_read_b
= callee
? ipa_reference_get_not_read_global (callee
) : NULL
;
1859 /* Add a VUSE for each call-clobbered variable. */
1860 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun
), 0, u
, bi
)
1862 tree var
= referenced_var (u
);
1863 tree real_var
= var
;
1866 clobber_stats
.readonly_clobbers
++;
1868 /* Not read and not written are computed on regular vars, not
1869 subvars, so look at the parent var if this is an SFT. */
1871 if (TREE_CODE (var
) == STRUCT_FIELD_TAG
)
1872 real_var
= SFT_PARENT_VAR (var
);
1874 not_read
= not_read_b
? bitmap_bit_p (not_read_b
, DECL_UID (real_var
))
1879 clobber_stats
.static_readonly_clobbers_avoided
++;
1883 add_virtual_operand (var
, s_ann
, opf_use
, NULL
, 0, -1, true);
1888 /* A subroutine of get_expr_operands to handle CALL_EXPR. */
1891 get_call_expr_operands (tree stmt
, tree expr
)
1893 int call_flags
= call_expr_flags (expr
);
1895 stmt_ann_t ann
= stmt_ann (stmt
);
1897 ann
->references_memory
= true;
1899 /* If aliases have been computed already, add VDEF or VUSE
1900 operands for all the symbols that have been found to be
1902 if (gimple_aliases_computed_p (cfun
)
1903 && !(call_flags
& ECF_NOVOPS
))
1905 /* A 'pure' or a 'const' function never call-clobbers anything.
1906 A 'noreturn' function might, but since we don't return anyway
1907 there is no point in recording that. */
1908 if (TREE_SIDE_EFFECTS (expr
)
1909 && !(call_flags
& (ECF_PURE
| ECF_CONST
| ECF_NORETURN
)))
1910 add_call_clobber_ops (stmt
, get_callee_fndecl (expr
));
1911 else if (!(call_flags
& ECF_CONST
))
1912 add_call_read_ops (stmt
, get_callee_fndecl (expr
));
1915 /* Find uses in the called function. */
1916 get_expr_operands (stmt
, &CALL_EXPR_FN (expr
), opf_use
);
1917 nargs
= call_expr_nargs (expr
);
1918 for (i
= 0; i
< nargs
; i
++)
1919 get_expr_operands (stmt
, &CALL_EXPR_ARG (expr
, i
), opf_use
);
1921 get_expr_operands (stmt
, &CALL_EXPR_STATIC_CHAIN (expr
), opf_use
);
1925 /* Scan operands in the ASM_EXPR stmt referred to in INFO. */
1928 get_asm_expr_operands (tree stmt
)
1932 const char **oconstraints
;
1933 const char *constraint
;
1934 bool allows_mem
, allows_reg
, is_inout
;
1937 s_ann
= stmt_ann (stmt
);
1938 noutputs
= list_length (ASM_OUTPUTS (stmt
));
1939 oconstraints
= (const char **) alloca ((noutputs
) * sizeof (const char *));
1941 /* Gather all output operands. */
1942 for (i
= 0, link
= ASM_OUTPUTS (stmt
); link
; i
++, link
= TREE_CHAIN (link
))
1944 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
1945 oconstraints
[i
] = constraint
;
1946 parse_output_constraint (&constraint
, i
, 0, 0, &allows_mem
,
1947 &allows_reg
, &is_inout
);
1949 /* This should have been split in gimplify_asm_expr. */
1950 gcc_assert (!allows_reg
|| !is_inout
);
1952 /* Memory operands are addressable. Note that STMT needs the
1953 address of this operand. */
1954 if (!allows_reg
&& allows_mem
)
1956 tree t
= get_base_address (TREE_VALUE (link
));
1957 if (t
&& DECL_P (t
) && s_ann
)
1958 add_to_addressable_set (t
, &s_ann
->addresses_taken
);
1961 get_expr_operands (stmt
, &TREE_VALUE (link
), opf_def
);
1964 /* Gather all input operands. */
1965 for (link
= ASM_INPUTS (stmt
); link
; link
= TREE_CHAIN (link
))
1967 constraint
= TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link
)));
1968 parse_input_constraint (&constraint
, 0, 0, noutputs
, 0, oconstraints
,
1969 &allows_mem
, &allows_reg
);
1971 /* Memory operands are addressable. Note that STMT needs the
1972 address of this operand. */
1973 if (!allows_reg
&& allows_mem
)
1975 tree t
= get_base_address (TREE_VALUE (link
));
1976 if (t
&& DECL_P (t
) && s_ann
)
1977 add_to_addressable_set (t
, &s_ann
->addresses_taken
);
1980 get_expr_operands (stmt
, &TREE_VALUE (link
), 0);
1983 /* Clobber all memory and addressable symbols for asm ("" : : : "memory"); */
1984 for (link
= ASM_CLOBBERS (stmt
); link
; link
= TREE_CHAIN (link
))
1985 if (strcmp (TREE_STRING_POINTER (TREE_VALUE (link
)), "memory") == 0)
1990 s_ann
->references_memory
= true;
1992 EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun
), 0, i
, bi
)
1994 tree var
= referenced_var (i
);
1995 add_stmt_operand (&var
, s_ann
, opf_def
| opf_implicit
);
1998 EXECUTE_IF_SET_IN_BITMAP (gimple_addressable_vars (cfun
), 0, i
, bi
)
2000 tree var
= referenced_var (i
);
2002 /* Subvars are explicitly represented in this list, so we
2003 don't need the original to be added to the clobber ops,
2004 but the original *will* be in this list because we keep
2005 the addressability of the original variable up-to-date
2006 to avoid confusing the back-end. */
2007 if (var_can_have_subvars (var
)
2008 && get_subvars_for_var (var
) != NULL
)
2011 add_stmt_operand (&var
, s_ann
, opf_def
| opf_implicit
);
2018 /* Scan operands for the assignment expression EXPR in statement STMT. */
2021 get_modify_stmt_operands (tree stmt
, tree expr
)
2023 /* First get operands from the RHS. */
2024 get_expr_operands (stmt
, &GIMPLE_STMT_OPERAND (expr
, 1), opf_use
);
2026 /* For the LHS, use a regular definition (opf_def) for GIMPLE
2027 registers. If the LHS is a store to memory, we will need
2028 a preserving definition (VDEF).
2030 Preserving definitions are those that modify a part of an
2031 aggregate object for which no subvars have been computed (or the
2032 reference does not correspond exactly to one of them). Stores
2033 through a pointer are also represented with VDEF operators.
2035 We used to distinguish between preserving and killing definitions.
2036 We always emit preserving definitions now. */
2037 get_expr_operands (stmt
, &GIMPLE_STMT_OPERAND (expr
, 0), opf_def
);
2041 /* Recursively scan the expression pointed to by EXPR_P in statement
2042 STMT. FLAGS is one of the OPF_* constants modifying how to
2043 interpret the operands found. */
2046 get_expr_operands (tree stmt
, tree
*expr_p
, int flags
)
2048 enum tree_code code
;
2049 enum tree_code_class codeclass
;
2050 tree expr
= *expr_p
;
2051 stmt_ann_t s_ann
= stmt_ann (stmt
);
2056 code
= TREE_CODE (expr
);
2057 codeclass
= TREE_CODE_CLASS (code
);
2062 /* Taking the address of a variable does not represent a
2063 reference to it, but the fact that the statement takes its
2064 address will be of interest to some passes (e.g. alias
2066 add_to_addressable_set (TREE_OPERAND (expr
, 0), &s_ann
->addresses_taken
);
2068 /* If the address is invariant, there may be no interesting
2069 variable references inside. */
2070 if (is_gimple_min_invariant (expr
))
2073 /* Otherwise, there may be variables referenced inside but there
2074 should be no VUSEs created, since the referenced objects are
2075 not really accessed. The only operands that we should find
2076 here are ARRAY_REF indices which will always be real operands
2077 (GIMPLE does not allow non-registers as array indices). */
2078 flags
|= opf_no_vops
;
2079 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2083 case STRUCT_FIELD_TAG
:
2084 case SYMBOL_MEMORY_TAG
:
2085 case NAME_MEMORY_TAG
:
2086 add_stmt_operand (expr_p
, s_ann
, flags
);
2095 /* Add the subvars for a variable, if it has subvars, to DEFS
2096 or USES. Otherwise, add the variable itself. Whether it
2097 goes to USES or DEFS depends on the operand flags. */
2098 if (var_can_have_subvars (expr
)
2099 && (svars
= get_subvars_for_var (expr
)))
2102 for (sv
= svars
; sv
; sv
= sv
->next
)
2103 add_stmt_operand (&sv
->var
, s_ann
, flags
);
2106 add_stmt_operand (expr_p
, s_ann
, flags
);
2111 case MISALIGNED_INDIRECT_REF
:
2112 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), flags
);
2115 case ALIGN_INDIRECT_REF
:
2117 get_indirect_ref_operands (stmt
, expr
, flags
, expr
, 0, -1, true);
2120 case TARGET_MEM_REF
:
2121 get_tmr_operands (stmt
, expr
, flags
);
2125 case ARRAY_RANGE_REF
:
2131 HOST_WIDE_INT offset
, size
, maxsize
;
2134 if (TREE_THIS_VOLATILE (expr
))
2135 s_ann
->has_volatile_ops
= true;
2137 /* This component reference becomes an access to all of the
2138 subvariables it can touch, if we can determine that, but
2139 *NOT* the real one. If we can't determine which fields we
2140 could touch, the recursion will eventually get to a
2141 variable and add *all* of its subvars, or whatever is the
2142 minimum correct subset. */
2143 ref
= get_ref_base_and_extent (expr
, &offset
, &size
, &maxsize
);
2144 if (SSA_VAR_P (ref
) && get_subvars_for_var (ref
))
2147 subvar_t svars
= get_subvars_for_var (ref
);
2149 for (sv
= svars
; sv
; sv
= sv
->next
)
2153 if (overlap_subvar (offset
, maxsize
, sv
->var
, &exact
))
2155 int subvar_flags
= flags
;
2157 add_stmt_operand (&sv
->var
, s_ann
, subvar_flags
);
2162 flags
|= opf_no_vops
;
2164 if ((DECL_P (ref
) && TREE_THIS_VOLATILE (ref
))
2165 || (TREE_CODE (ref
) == SSA_NAME
2166 && TREE_THIS_VOLATILE (SSA_NAME_VAR (ref
))))
2167 s_ann
->has_volatile_ops
= true;
2169 else if (TREE_CODE (ref
) == INDIRECT_REF
)
2171 get_indirect_ref_operands (stmt
, ref
, flags
, expr
, offset
,
2173 flags
|= opf_no_vops
;
2176 /* Even if we found subvars above we need to ensure to see
2177 immediate uses for d in s.a[d]. In case of s.a having
2178 a subvar or we would miss it otherwise. */
2179 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2181 if (code
== COMPONENT_REF
)
2183 if (TREE_THIS_VOLATILE (TREE_OPERAND (expr
, 1)))
2184 s_ann
->has_volatile_ops
= true;
2185 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 2), opf_use
);
2187 else if (code
== ARRAY_REF
|| code
== ARRAY_RANGE_REF
)
2189 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), opf_use
);
2190 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 2), opf_use
);
2191 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 3), opf_use
);
2197 case WITH_SIZE_EXPR
:
2198 /* WITH_SIZE_EXPR is a pass-through reference to its first argument,
2199 and an rvalue reference to its second argument. */
2200 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), opf_use
);
2201 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2205 get_call_expr_operands (stmt
, expr
);
2210 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), opf_use
);
2211 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), opf_use
);
2212 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 2), opf_use
);
2215 case GIMPLE_MODIFY_STMT
:
2216 get_modify_stmt_operands (stmt
, expr
);
2221 /* General aggregate CONSTRUCTORs have been decomposed, but they
2222 are still in use as the COMPLEX_EXPR equivalent for vectors. */
2223 constructor_elt
*ce
;
2224 unsigned HOST_WIDE_INT idx
;
2227 VEC_iterate (constructor_elt
, CONSTRUCTOR_ELTS (expr
), idx
, ce
);
2229 get_expr_operands (stmt
, &ce
->value
, opf_use
);
2235 case TRUTH_NOT_EXPR
:
2236 case VIEW_CONVERT_EXPR
:
2238 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2241 case TRUTH_AND_EXPR
:
2243 case TRUTH_XOR_EXPR
:
2249 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2250 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), flags
);
2255 case REALIGN_LOAD_EXPR
:
2257 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), flags
);
2258 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), flags
);
2259 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 2), flags
);
2263 case CHANGE_DYNAMIC_TYPE_EXPR
:
2264 get_expr_operands (stmt
, &CHANGE_DYNAMIC_TYPE_LOCATION (expr
), opf_use
);
2269 tree init
= OMP_FOR_INIT (expr
);
2270 tree cond
= OMP_FOR_COND (expr
);
2271 tree incr
= OMP_FOR_INCR (expr
);
2272 tree c
, clauses
= OMP_FOR_CLAUSES (stmt
);
2274 get_expr_operands (stmt
, &GIMPLE_STMT_OPERAND (init
, 0), opf_def
);
2275 get_expr_operands (stmt
, &GIMPLE_STMT_OPERAND (init
, 1), opf_use
);
2276 get_expr_operands (stmt
, &TREE_OPERAND (cond
, 1), opf_use
);
2277 get_expr_operands (stmt
, &TREE_OPERAND (GIMPLE_STMT_OPERAND (incr
, 1), 1),
2280 c
= find_omp_clause (clauses
, OMP_CLAUSE_SCHEDULE
);
2282 get_expr_operands (stmt
, &OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c
),
2289 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 0), opf_def
);
2290 get_expr_operands (stmt
, &TREE_OPERAND (expr
, 1), opf_use
);
2296 tree c
, clauses
= OMP_PARALLEL_CLAUSES (stmt
);
2298 if (OMP_PARALLEL_DATA_ARG (stmt
))
2300 get_expr_operands (stmt
, &OMP_PARALLEL_DATA_ARG (stmt
), opf_use
);
2301 add_to_addressable_set (OMP_PARALLEL_DATA_ARG (stmt
),
2302 &s_ann
->addresses_taken
);
2305 c
= find_omp_clause (clauses
, OMP_CLAUSE_IF
);
2307 get_expr_operands (stmt
, &OMP_CLAUSE_IF_EXPR (c
), opf_use
);
2308 c
= find_omp_clause (clauses
, OMP_CLAUSE_NUM_THREADS
);
2310 get_expr_operands (stmt
, &OMP_CLAUSE_NUM_THREADS_EXPR (c
), opf_use
);
2316 get_expr_operands (stmt
, &OMP_SECTIONS_CONTROL (expr
), opf_def
);
2332 case OMP_SECTIONS_SWITCH
:
2333 /* Expressions that make no memory references. */
2337 if (codeclass
== tcc_unary
)
2339 if (codeclass
== tcc_binary
|| codeclass
== tcc_comparison
)
2341 if (codeclass
== tcc_constant
|| codeclass
== tcc_type
)
2345 /* If we get here, something has gone wrong. */
2346 #ifdef ENABLE_CHECKING
2347 fprintf (stderr
, "unhandled expression in get_expr_operands():\n");
2349 fputs ("\n", stderr
);
2355 /* Parse STMT looking for operands. When finished, the various
2356 build_* operand vectors will have potential operands in them. */
2359 parse_ssa_operands (tree stmt
)
2361 enum tree_code code
;
2363 code
= TREE_CODE (stmt
);
2366 case GIMPLE_MODIFY_STMT
:
2367 get_modify_stmt_operands (stmt
, stmt
);
2371 get_expr_operands (stmt
, &COND_EXPR_COND (stmt
), opf_use
);
2375 get_expr_operands (stmt
, &SWITCH_COND (stmt
), opf_use
);
2379 get_asm_expr_operands (stmt
);
2383 get_expr_operands (stmt
, &TREE_OPERAND (stmt
, 0), opf_use
);
2387 get_expr_operands (stmt
, &GOTO_DESTINATION (stmt
), opf_use
);
2391 get_expr_operands (stmt
, &LABEL_EXPR_LABEL (stmt
), opf_use
);
2395 case CASE_LABEL_EXPR
:
2396 case TRY_CATCH_EXPR
:
2397 case TRY_FINALLY_EXPR
:
2398 case EH_FILTER_EXPR
:
2401 /* These nodes contain no variable references. */
2405 /* Notice that if get_expr_operands tries to use &STMT as the
2406 operand pointer (which may only happen for USE operands), we
2407 will fail in add_stmt_operand. This default will handle
2408 statements like empty statements, or CALL_EXPRs that may
2409 appear on the RHS of a statement or as statements themselves. */
2410 get_expr_operands (stmt
, &stmt
, opf_use
);
2416 /* Create an operands cache for STMT. */
2419 build_ssa_operands (tree stmt
)
2421 stmt_ann_t ann
= get_stmt_ann (stmt
);
2423 /* Initially assume that the statement has no volatile operands and
2424 makes no memory references. */
2425 ann
->has_volatile_ops
= false;
2426 ann
->references_memory
= false;
2427 /* Just clear the bitmap so we don't end up reallocating it over and over. */
2428 if (ann
->addresses_taken
)
2429 bitmap_clear (ann
->addresses_taken
);
2431 start_ssa_stmt_operands ();
2432 parse_ssa_operands (stmt
);
2433 operand_build_sort_virtual (build_vuses
);
2434 operand_build_sort_virtual (build_vdefs
);
2435 finalize_ssa_stmt_operands (stmt
);
2437 if (ann
->addresses_taken
&& bitmap_empty_p (ann
->addresses_taken
))
2438 ann
->addresses_taken
= NULL
;
2439 /* For added safety, assume that statements with volatile operands
2440 also reference memory. */
2441 if (ann
->has_volatile_ops
)
2442 ann
->references_memory
= true;
2446 /* Free any operands vectors in OPS. */
2449 free_ssa_operands (stmt_operands_p ops
)
2451 ops
->def_ops
= NULL
;
2452 ops
->use_ops
= NULL
;
2453 ops
->vdef_ops
= NULL
;
2454 ops
->vuse_ops
= NULL
;
2455 BITMAP_FREE (ops
->loads
);
2456 BITMAP_FREE (ops
->stores
);
2460 /* Get the operands of statement STMT. */
2463 update_stmt_operands (tree stmt
)
2465 stmt_ann_t ann
= get_stmt_ann (stmt
);
2467 /* If update_stmt_operands is called before SSA is initialized, do
2469 if (!ssa_operands_active ())
2472 /* The optimizers cannot handle statements that are nothing but a
2473 _DECL. This indicates a bug in the gimplifier. */
2474 gcc_assert (!SSA_VAR_P (stmt
));
2476 timevar_push (TV_TREE_OPS
);
2478 gcc_assert (ann
->modified
);
2479 build_ssa_operands (stmt
);
2482 timevar_pop (TV_TREE_OPS
);
2486 /* Copies virtual operands from SRC to DST. */
2489 copy_virtual_operands (tree dest
, tree src
)
2492 voptype_p src_vuses
, dest_vuses
;
2493 voptype_p src_vdefs
, dest_vdefs
;
2494 struct voptype_d vuse
;
2495 struct voptype_d vdef
;
2496 stmt_ann_t dest_ann
;
2498 VDEF_OPS (dest
) = NULL
;
2499 VUSE_OPS (dest
) = NULL
;
2501 dest_ann
= get_stmt_ann (dest
);
2502 BITMAP_FREE (dest_ann
->operands
.loads
);
2503 BITMAP_FREE (dest_ann
->operands
.stores
);
2505 if (LOADED_SYMS (src
))
2507 dest_ann
->operands
.loads
= BITMAP_ALLOC (&operands_bitmap_obstack
);
2508 bitmap_copy (dest_ann
->operands
.loads
, LOADED_SYMS (src
));
2511 if (STORED_SYMS (src
))
2513 dest_ann
->operands
.stores
= BITMAP_ALLOC (&operands_bitmap_obstack
);
2514 bitmap_copy (dest_ann
->operands
.stores
, STORED_SYMS (src
));
2517 /* Copy all the VUSE operators and corresponding operands. */
2519 for (src_vuses
= VUSE_OPS (src
); src_vuses
; src_vuses
= src_vuses
->next
)
2521 n
= VUSE_NUM (src_vuses
);
2522 dest_vuses
= add_vuse_op (dest
, NULL_TREE
, n
, dest_vuses
);
2523 for (i
= 0; i
< n
; i
++)
2524 SET_USE (VUSE_OP_PTR (dest_vuses
, i
), VUSE_OP (src_vuses
, i
));
2526 if (VUSE_OPS (dest
) == NULL
)
2527 VUSE_OPS (dest
) = vuse
.next
;
2530 /* Copy all the VDEF operators and corresponding operands. */
2532 for (src_vdefs
= VDEF_OPS (src
); src_vdefs
; src_vdefs
= src_vdefs
->next
)
2534 n
= VUSE_NUM (src_vdefs
);
2535 dest_vdefs
= add_vdef_op (dest
, NULL_TREE
, n
, dest_vdefs
);
2536 VDEF_RESULT (dest_vdefs
) = VDEF_RESULT (src_vdefs
);
2537 for (i
= 0; i
< n
; i
++)
2538 SET_USE (VUSE_OP_PTR (dest_vdefs
, i
), VUSE_OP (src_vdefs
, i
));
2540 if (VDEF_OPS (dest
) == NULL
)
2541 VDEF_OPS (dest
) = vdef
.next
;
2546 /* Specifically for use in DOM's expression analysis. Given a store, we
2547 create an artificial stmt which looks like a load from the store, this can
2548 be used to eliminate redundant loads. OLD_OPS are the operands from the
2549 store stmt, and NEW_STMT is the new load which represents a load of the
2553 create_ssa_artificial_load_stmt (tree new_stmt
, tree old_stmt
)
2557 use_operand_p use_p
;
2560 get_stmt_ann (new_stmt
);
2562 /* Process NEW_STMT looking for operands. */
2563 start_ssa_stmt_operands ();
2564 parse_ssa_operands (new_stmt
);
2566 for (i
= 0; VEC_iterate (tree
, build_vuses
, i
, op
); i
++)
2567 if (TREE_CODE (op
) != SSA_NAME
)
2568 var_ann (op
)->in_vuse_list
= false;
2570 for (i
= 0; VEC_iterate (tree
, build_vuses
, i
, op
); i
++)
2571 if (TREE_CODE (op
) != SSA_NAME
)
2572 var_ann (op
)->in_vdef_list
= false;
2574 /* Remove any virtual operands that were found. */
2575 VEC_truncate (tree
, build_vdefs
, 0);
2576 VEC_truncate (tree
, build_vuses
, 0);
2578 /* For each VDEF on the original statement, we want to create a
2579 VUSE of the VDEF result operand on the new statement. */
2580 FOR_EACH_SSA_TREE_OPERAND (op
, old_stmt
, iter
, SSA_OP_VDEF
)
2583 finalize_ssa_stmt_operands (new_stmt
);
2585 /* All uses in this fake stmt must not be in the immediate use lists. */
2586 FOR_EACH_SSA_USE_OPERAND (use_p
, new_stmt
, iter
, SSA_OP_ALL_USES
)
2587 delink_imm_use (use_p
);
2591 /* Swap operands EXP0 and EXP1 in statement STMT. No attempt is done
2592 to test the validity of the swap operation. */
2595 swap_tree_operands (tree stmt
, tree
*exp0
, tree
*exp1
)
2601 /* If the operand cache is active, attempt to preserve the relative
2602 positions of these two operands in their respective immediate use
2604 if (ssa_operands_active () && op0
!= op1
)
2606 use_optype_p use0
, use1
, ptr
;
2609 /* Find the 2 operands in the cache, if they are there. */
2610 for (ptr
= USE_OPS (stmt
); ptr
; ptr
= ptr
->next
)
2611 if (USE_OP_PTR (ptr
)->use
== exp0
)
2617 for (ptr
= USE_OPS (stmt
); ptr
; ptr
= ptr
->next
)
2618 if (USE_OP_PTR (ptr
)->use
== exp1
)
2624 /* If both uses don't have operand entries, there isn't much we can do
2625 at this point. Presumably we don't need to worry about it. */
2628 tree
*tmp
= USE_OP_PTR (use1
)->use
;
2629 USE_OP_PTR (use1
)->use
= USE_OP_PTR (use0
)->use
;
2630 USE_OP_PTR (use0
)->use
= tmp
;
2634 /* Now swap the data. */
2640 /* Add the base address of REF to the set *ADDRESSES_TAKEN. If
2641 *ADDRESSES_TAKEN is NULL, a new set is created. REF may be
2642 a single variable whose address has been taken or any other valid
2643 GIMPLE memory reference (structure reference, array, etc). If the
2644 base address of REF is a decl that has sub-variables, also add all
2645 of its sub-variables. */
2648 add_to_addressable_set (tree ref
, bitmap
*addresses_taken
)
2653 gcc_assert (addresses_taken
);
2655 /* Note that it is *NOT OKAY* to use the target of a COMPONENT_REF
2656 as the only thing we take the address of. If VAR is a structure,
2657 taking the address of a field means that the whole structure may
2658 be referenced using pointer arithmetic. See PR 21407 and the
2659 ensuing mailing list discussion. */
2660 var
= get_base_address (ref
);
2661 if (var
&& SSA_VAR_P (var
))
2663 if (*addresses_taken
== NULL
)
2664 *addresses_taken
= BITMAP_GGC_ALLOC ();
2666 if (var_can_have_subvars (var
)
2667 && (svars
= get_subvars_for_var (var
)))
2670 for (sv
= svars
; sv
; sv
= sv
->next
)
2672 bitmap_set_bit (*addresses_taken
, DECL_UID (sv
->var
));
2673 TREE_ADDRESSABLE (sv
->var
) = 1;
2678 bitmap_set_bit (*addresses_taken
, DECL_UID (var
));
2679 TREE_ADDRESSABLE (var
) = 1;
2685 /* Scan the immediate_use list for VAR making sure its linked properly.
2686 Return TRUE if there is a problem and emit an error message to F. */
2689 verify_imm_links (FILE *f
, tree var
)
2691 use_operand_p ptr
, prev
, list
;
2694 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
2696 list
= &(SSA_NAME_IMM_USE_NODE (var
));
2697 gcc_assert (list
->use
== NULL
);
2699 if (list
->prev
== NULL
)
2701 gcc_assert (list
->next
== NULL
);
2707 for (ptr
= list
->next
; ptr
!= list
; )
2709 if (prev
!= ptr
->prev
)
2712 if (ptr
->use
== NULL
)
2713 goto error
; /* 2 roots, or SAFE guard node. */
2714 else if (*(ptr
->use
) != var
)
2720 /* Avoid infinite loops. 50,000,000 uses probably indicates a
2722 if (count
++ > 50000000)
2726 /* Verify list in the other direction. */
2728 for (ptr
= list
->prev
; ptr
!= list
; )
2730 if (prev
!= ptr
->next
)
2744 if (ptr
->stmt
&& stmt_modified_p (ptr
->stmt
))
2746 fprintf (f
, " STMT MODIFIED. - <%p> ", (void *)ptr
->stmt
);
2747 print_generic_stmt (f
, ptr
->stmt
, TDF_SLIM
);
2749 fprintf (f
, " IMM ERROR : (use_p : tree - %p:%p)", (void *)ptr
,
2751 print_generic_expr (f
, USE_FROM_PTR (ptr
), TDF_SLIM
);
2757 /* Dump all the immediate uses to FILE. */
2760 dump_immediate_uses_for (FILE *file
, tree var
)
2762 imm_use_iterator iter
;
2763 use_operand_p use_p
;
2765 gcc_assert (var
&& TREE_CODE (var
) == SSA_NAME
);
2767 print_generic_expr (file
, var
, TDF_SLIM
);
2768 fprintf (file
, " : -->");
2769 if (has_zero_uses (var
))
2770 fprintf (file
, " no uses.\n");
2772 if (has_single_use (var
))
2773 fprintf (file
, " single use.\n");
2775 fprintf (file
, "%d uses.\n", num_imm_uses (var
));
2777 FOR_EACH_IMM_USE_FAST (use_p
, iter
, var
)
2779 if (use_p
->stmt
== NULL
&& use_p
->use
== NULL
)
2780 fprintf (file
, "***end of stmt iterator marker***\n");
2782 if (!is_gimple_reg (USE_FROM_PTR (use_p
)))
2783 print_generic_stmt (file
, USE_STMT (use_p
), TDF_VOPS
|TDF_MEMSYMS
);
2785 print_generic_stmt (file
, USE_STMT (use_p
), TDF_SLIM
);
2787 fprintf(file
, "\n");
2791 /* Dump all the immediate uses to FILE. */
2794 dump_immediate_uses (FILE *file
)
2799 fprintf (file
, "Immediate_uses: \n\n");
2800 for (x
= 1; x
< num_ssa_names
; x
++)
2805 dump_immediate_uses_for (file
, var
);
2810 /* Dump def-use edges on stderr. */
2813 debug_immediate_uses (void)
2815 dump_immediate_uses (stderr
);
2819 /* Dump def-use edges on stderr. */
2822 debug_immediate_uses_for (tree var
)
2824 dump_immediate_uses_for (stderr
, var
);
2828 /* Create a new change buffer for the statement pointed by STMT_P and
2829 push the buffer into SCB_STACK. Each change buffer
2830 records state information needed to determine what changed in the
2831 statement. Mainly, this keeps track of symbols that may need to be
2832 put into SSA form, SSA name replacements and other information
2833 needed to keep the SSA form up to date. */
2836 push_stmt_changes (tree
*stmt_p
)
2843 /* It makes no sense to keep track of PHI nodes. */
2844 if (TREE_CODE (stmt
) == PHI_NODE
)
2847 buf
= XNEW (struct scb_d
);
2848 memset (buf
, 0, sizeof *buf
);
2850 buf
->stmt_p
= stmt_p
;
2852 if (stmt_references_memory_p (stmt
))
2857 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_VUSE
)
2859 tree sym
= TREE_CODE (op
) == SSA_NAME
? SSA_NAME_VAR (op
) : op
;
2860 if (buf
->loads
== NULL
)
2861 buf
->loads
= BITMAP_ALLOC (NULL
);
2862 bitmap_set_bit (buf
->loads
, DECL_UID (sym
));
2865 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_VDEF
)
2867 tree sym
= TREE_CODE (op
) == SSA_NAME
? SSA_NAME_VAR (op
) : op
;
2868 if (buf
->stores
== NULL
)
2869 buf
->stores
= BITMAP_ALLOC (NULL
);
2870 bitmap_set_bit (buf
->stores
, DECL_UID (sym
));
2874 VEC_safe_push (scb_t
, heap
, scb_stack
, buf
);
2878 /* Given two sets S1 and S2, mark the symbols that differ in S1 and S2
2879 for renaming. The set to mark for renaming is (S1 & ~S2) | (S2 & ~S1). */
2882 mark_difference_for_renaming (bitmap s1
, bitmap s2
)
2884 if (s1
== NULL
&& s2
== NULL
)
2887 if (s1
&& s2
== NULL
)
2888 mark_set_for_renaming (s1
);
2889 else if (s1
== NULL
&& s2
)
2890 mark_set_for_renaming (s2
);
2891 else if (!bitmap_equal_p (s1
, s2
))
2893 bitmap t1
= BITMAP_ALLOC (NULL
);
2894 bitmap t2
= BITMAP_ALLOC (NULL
);
2896 bitmap_and_compl (t1
, s1
, s2
);
2897 bitmap_and_compl (t2
, s2
, s1
);
2898 bitmap_ior_into (t1
, t2
);
2899 mark_set_for_renaming (t1
);
2907 /* Pop the top SCB from SCB_STACK and act on the differences between
2908 what was recorded by push_stmt_changes and the current state of
2912 pop_stmt_changes (tree
*stmt_p
)
2916 bitmap loads
, stores
;
2921 /* It makes no sense to keep track of PHI nodes. */
2922 if (TREE_CODE (stmt
) == PHI_NODE
)
2925 buf
= VEC_pop (scb_t
, scb_stack
);
2926 gcc_assert (stmt_p
== buf
->stmt_p
);
2928 /* Force an operand re-scan on the statement and mark any newly
2929 exposed variables. */
2932 /* Determine whether any memory symbols need to be renamed. If the
2933 sets of loads and stores are different after the statement is
2934 modified, then the affected symbols need to be renamed.
2936 Note that it may be possible for the statement to not reference
2937 memory anymore, but we still need to act on the differences in
2938 the sets of symbols. */
2939 loads
= stores
= NULL
;
2940 if (stmt_references_memory_p (stmt
))
2945 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_VUSE
)
2947 tree sym
= TREE_CODE (op
) == SSA_NAME
? SSA_NAME_VAR (op
) : op
;
2949 loads
= BITMAP_ALLOC (NULL
);
2950 bitmap_set_bit (loads
, DECL_UID (sym
));
2953 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_VDEF
)
2955 tree sym
= TREE_CODE (op
) == SSA_NAME
? SSA_NAME_VAR (op
) : op
;
2957 stores
= BITMAP_ALLOC (NULL
);
2958 bitmap_set_bit (stores
, DECL_UID (sym
));
2962 /* If LOADS is different from BUF->LOADS, the affected
2963 symbols need to be marked for renaming. */
2964 mark_difference_for_renaming (loads
, buf
->loads
);
2966 /* Similarly for STORES and BUF->STORES. */
2967 mark_difference_for_renaming (stores
, buf
->stores
);
2969 /* Mark all the naked GIMPLE register operands for renaming. */
2970 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, iter
, SSA_OP_DEF
|SSA_OP_USE
)
2972 mark_sym_for_renaming (op
);
2974 /* FIXME, need to add more finalizers here. Cleanup EH info,
2975 recompute invariants for address expressions, add
2976 SSA replacement mappings, etc. For instance, given
2977 testsuite/gcc.c-torture/compile/pr16808.c, we fold a statement of
2980 # SMT.4_20 = VDEF <SMT.4_16>
2983 So, the VDEF will disappear, but instead of marking SMT.4 for
2984 renaming it would be far more efficient to establish a
2985 replacement mapping that would replace every reference of
2986 SMT.4_20 with SMT.4_16. */
2988 /* Free memory used by the buffer. */
2989 BITMAP_FREE (buf
->loads
);
2990 BITMAP_FREE (buf
->stores
);
2991 BITMAP_FREE (loads
);
2992 BITMAP_FREE (stores
);
2998 /* Discard the topmost change buffer from SCB_STACK. This is useful
2999 when the caller realized that it did not actually modified the
3000 statement. It avoids the expensive operand re-scan. */
3003 discard_stmt_changes (tree
*stmt_p
)
3008 /* It makes no sense to keep track of PHI nodes. */
3010 if (TREE_CODE (stmt
) == PHI_NODE
)
3013 buf
= VEC_pop (scb_t
, scb_stack
);
3014 gcc_assert (stmt_p
== buf
->stmt_p
);
3016 /* Free memory used by the buffer. */
3017 BITMAP_FREE (buf
->loads
);
3018 BITMAP_FREE (buf
->stores
);
3024 /* Returns true if statement STMT may access memory. */
3027 stmt_references_memory_p (tree stmt
)
3029 if (!gimple_ssa_operands (cfun
)->ops_active
|| TREE_CODE (stmt
) == PHI_NODE
)
3032 return stmt_ann (stmt
)->references_memory
;