1 /* Alias analysis for trees.
2 Copyright (C) 2004-2013 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
28 #include "basic-block.h"
29 #include "timevar.h" /* for TV_ALIAS_STMT_WALK */
31 #include "langhooks.h"
34 #include "tree-pretty-print.h"
37 #include "gimple-ssa.h"
38 #include "stringpool.h"
39 #include "tree-ssanames.h"
42 #include "tree-inline.h"
45 #include "pointer-set.h"
46 #include "alloc-pool.h"
47 #include "tree-ssa-alias.h"
48 #include "ipa-reference.h"
50 /* Broad overview of how alias analysis on gimple works:
52 Statements clobbering or using memory are linked through the
53 virtual operand factored use-def chain. The virtual operand
54 is unique per function, its symbol is accessible via gimple_vop (cfun).
55 Virtual operands are used for efficiently walking memory statements
56 in the gimple IL and are useful for things like value-numbering as
57 a generation count for memory references.
59 SSA_NAME pointers may have associated points-to information
60 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
61 points-to information is (re-)computed by the TODO_rebuild_alias
62 pass manager todo. Points-to information is also used for more
63 precise tracking of call-clobbered and call-used variables and
64 related disambiguations.
66 This file contains functions for disambiguating memory references,
67 the so called alias-oracle and tools for walking of the gimple IL.
69 The main alias-oracle entry-points are
71 bool stmt_may_clobber_ref_p (gimple, tree)
73 This function queries if a statement may invalidate (parts of)
74 the memory designated by the reference tree argument.
76 bool ref_maybe_used_by_stmt_p (gimple, tree)
78 This function queries if a statement may need (parts of) the
79 memory designated by the reference tree argument.
81 There are variants of these functions that only handle the call
82 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
83 Note that these do not disambiguate against a possible call lhs.
85 bool refs_may_alias_p (tree, tree)
87 This function tries to disambiguate two reference trees.
89 bool ptr_deref_may_alias_global_p (tree)
91 This function queries if dereferencing a pointer variable may
94 More low-level disambiguators are available and documented in
95 this file. Low-level disambiguators dealing with points-to
96 information are in tree-ssa-structalias.c. */
99 /* Query statistics for the different low-level disambiguators.
100 A high-level query may trigger multiple of them. */
103 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
104 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
105 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
106 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
107 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
108 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
112 dump_alias_stats (FILE *s
)
114 fprintf (s
, "\nAlias oracle query stats:\n");
115 fprintf (s
, " refs_may_alias_p: "
116 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
117 HOST_WIDE_INT_PRINT_DEC
" queries\n",
118 alias_stats
.refs_may_alias_p_no_alias
,
119 alias_stats
.refs_may_alias_p_no_alias
120 + alias_stats
.refs_may_alias_p_may_alias
);
121 fprintf (s
, " ref_maybe_used_by_call_p: "
122 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
123 HOST_WIDE_INT_PRINT_DEC
" queries\n",
124 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
125 alias_stats
.refs_may_alias_p_no_alias
126 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
127 fprintf (s
, " call_may_clobber_ref_p: "
128 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
129 HOST_WIDE_INT_PRINT_DEC
" queries\n",
130 alias_stats
.call_may_clobber_ref_p_no_alias
,
131 alias_stats
.call_may_clobber_ref_p_no_alias
132 + alias_stats
.call_may_clobber_ref_p_may_alias
);
136 /* Return true, if dereferencing PTR may alias with a global variable. */
139 ptr_deref_may_alias_global_p (tree ptr
)
141 struct ptr_info_def
*pi
;
143 /* If we end up with a pointer constant here that may point
145 if (TREE_CODE (ptr
) != SSA_NAME
)
148 pi
= SSA_NAME_PTR_INFO (ptr
);
150 /* If we do not have points-to information for this variable,
155 /* ??? This does not use TBAA to prune globals ptr may not access. */
156 return pt_solution_includes_global (&pi
->pt
);
159 /* Return true if dereferencing PTR may alias DECL.
160 The caller is responsible for applying TBAA to see if PTR
161 may access DECL at all. */
164 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
166 struct ptr_info_def
*pi
;
168 /* Conversions are irrelevant for points-to information and
169 data-dependence analysis can feed us those. */
172 /* Anything we do not explicilty handle aliases. */
173 if ((TREE_CODE (ptr
) != SSA_NAME
174 && TREE_CODE (ptr
) != ADDR_EXPR
175 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
176 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
177 || (TREE_CODE (decl
) != VAR_DECL
178 && TREE_CODE (decl
) != PARM_DECL
179 && TREE_CODE (decl
) != RESULT_DECL
))
182 /* Disregard pointer offsetting. */
183 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
187 ptr
= TREE_OPERAND (ptr
, 0);
189 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
190 return ptr_deref_may_alias_decl_p (ptr
, decl
);
193 /* ADDR_EXPR pointers either just offset another pointer or directly
194 specify the pointed-to set. */
195 if (TREE_CODE (ptr
) == ADDR_EXPR
)
197 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
199 && (TREE_CODE (base
) == MEM_REF
200 || TREE_CODE (base
) == TARGET_MEM_REF
))
201 ptr
= TREE_OPERAND (base
, 0);
206 && CONSTANT_CLASS_P (base
))
212 /* Non-aliased variables can not be pointed to. */
213 if (!may_be_aliased (decl
))
216 /* If we do not have useful points-to information for this pointer
217 we cannot disambiguate anything else. */
218 pi
= SSA_NAME_PTR_INFO (ptr
);
222 return pt_solution_includes (&pi
->pt
, decl
);
225 /* Return true if dereferenced PTR1 and PTR2 may alias.
226 The caller is responsible for applying TBAA to see if accesses
227 through PTR1 and PTR2 may conflict at all. */
230 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
232 struct ptr_info_def
*pi1
, *pi2
;
234 /* Conversions are irrelevant for points-to information and
235 data-dependence analysis can feed us those. */
239 /* Disregard pointer offsetting. */
240 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
244 ptr1
= TREE_OPERAND (ptr1
, 0);
246 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
247 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
249 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
253 ptr2
= TREE_OPERAND (ptr2
, 0);
255 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
256 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
259 /* ADDR_EXPR pointers either just offset another pointer or directly
260 specify the pointed-to set. */
261 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
263 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
265 && (TREE_CODE (base
) == MEM_REF
266 || TREE_CODE (base
) == TARGET_MEM_REF
))
267 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
270 return ptr_deref_may_alias_decl_p (ptr2
, base
);
274 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
276 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
278 && (TREE_CODE (base
) == MEM_REF
279 || TREE_CODE (base
) == TARGET_MEM_REF
))
280 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
283 return ptr_deref_may_alias_decl_p (ptr1
, base
);
288 /* From here we require SSA name pointers. Anything else aliases. */
289 if (TREE_CODE (ptr1
) != SSA_NAME
290 || TREE_CODE (ptr2
) != SSA_NAME
291 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
292 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
295 /* We may end up with two empty points-to solutions for two same pointers.
296 In this case we still want to say both pointers alias, so shortcut
301 /* If we do not have useful points-to information for either pointer
302 we cannot disambiguate anything else. */
303 pi1
= SSA_NAME_PTR_INFO (ptr1
);
304 pi2
= SSA_NAME_PTR_INFO (ptr2
);
308 /* ??? This does not use TBAA to prune decls from the intersection
309 that not both pointers may access. */
310 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
313 /* Return true if dereferencing PTR may alias *REF.
314 The caller is responsible for applying TBAA to see if PTR
315 may access *REF at all. */
318 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
320 tree base
= ao_ref_base (ref
);
322 if (TREE_CODE (base
) == MEM_REF
323 || TREE_CODE (base
) == TARGET_MEM_REF
)
324 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
325 else if (DECL_P (base
))
326 return ptr_deref_may_alias_decl_p (ptr
, base
);
331 /* Return true whether REF may refer to global memory. */
334 ref_may_alias_global_p (tree ref
)
336 tree base
= get_base_address (ref
);
338 return is_global_var (base
);
339 else if (TREE_CODE (base
) == MEM_REF
340 || TREE_CODE (base
) == TARGET_MEM_REF
)
341 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
345 /* Return true whether STMT may clobber global memory. */
348 stmt_may_clobber_global_p (gimple stmt
)
352 if (!gimple_vdef (stmt
))
355 /* ??? We can ask the oracle whether an artificial pointer
356 dereference with a pointer with points-to information covering
357 all global memory (what about non-address taken memory?) maybe
358 clobbered by this call. As there is at the moment no convenient
359 way of doing that without generating garbage do some manual
361 ??? We could make a NULL ao_ref argument to the various
362 predicates special, meaning any global memory. */
364 switch (gimple_code (stmt
))
367 lhs
= gimple_assign_lhs (stmt
);
368 return (TREE_CODE (lhs
) != SSA_NAME
369 && ref_may_alias_global_p (lhs
));
378 /* Dump alias information on FILE. */
381 dump_alias_info (FILE *file
)
385 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
388 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
390 fprintf (file
, "Aliased symbols\n\n");
392 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
394 if (may_be_aliased (var
))
395 dump_variable (file
, var
);
398 fprintf (file
, "\nCall clobber information\n");
400 fprintf (file
, "\nESCAPED");
401 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
403 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
405 for (i
= 1; i
< num_ssa_names
; i
++)
407 tree ptr
= ssa_name (i
);
408 struct ptr_info_def
*pi
;
411 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
412 || SSA_NAME_IN_FREE_LIST (ptr
))
415 pi
= SSA_NAME_PTR_INFO (ptr
);
417 dump_points_to_info_for (file
, ptr
);
420 fprintf (file
, "\n");
424 /* Dump alias information on stderr. */
427 debug_alias_info (void)
429 dump_alias_info (stderr
);
433 /* Dump the points-to set *PT into FILE. */
436 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
439 fprintf (file
, ", points-to anything");
442 fprintf (file
, ", points-to non-local");
445 fprintf (file
, ", points-to escaped");
448 fprintf (file
, ", points-to unit escaped");
451 fprintf (file
, ", points-to NULL");
455 fprintf (file
, ", points-to vars: ");
456 dump_decl_set (file
, pt
->vars
);
457 if (pt
->vars_contains_nonlocal
458 && pt
->vars_contains_escaped_heap
)
459 fprintf (file
, " (nonlocal, escaped heap)");
460 else if (pt
->vars_contains_nonlocal
461 && pt
->vars_contains_escaped
)
462 fprintf (file
, " (nonlocal, escaped)");
463 else if (pt
->vars_contains_nonlocal
)
464 fprintf (file
, " (nonlocal)");
465 else if (pt
->vars_contains_escaped_heap
)
466 fprintf (file
, " (escaped heap)");
467 else if (pt
->vars_contains_escaped
)
468 fprintf (file
, " (escaped)");
473 /* Unified dump function for pt_solution. */
476 debug (pt_solution
&ref
)
478 dump_points_to_solution (stderr
, &ref
);
482 debug (pt_solution
*ptr
)
487 fprintf (stderr
, "<nil>\n");
491 /* Dump points-to information for SSA_NAME PTR into FILE. */
494 dump_points_to_info_for (FILE *file
, tree ptr
)
496 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
498 print_generic_expr (file
, ptr
, dump_flags
);
501 dump_points_to_solution (file
, &pi
->pt
);
503 fprintf (file
, ", points-to anything");
505 fprintf (file
, "\n");
509 /* Dump points-to information for VAR into stderr. */
512 debug_points_to_info_for (tree var
)
514 dump_points_to_info_for (stderr
, var
);
518 /* Initializes the alias-oracle reference representation *R from REF. */
521 ao_ref_init (ao_ref
*r
, tree ref
)
528 r
->ref_alias_set
= -1;
529 r
->base_alias_set
= -1;
530 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
533 /* Returns the base object of the memory reference *REF. */
536 ao_ref_base (ao_ref
*ref
)
540 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
545 /* Returns the base object alias set of the memory reference *REF. */
547 static alias_set_type
548 ao_ref_base_alias_set (ao_ref
*ref
)
551 if (ref
->base_alias_set
!= -1)
552 return ref
->base_alias_set
;
556 while (handled_component_p (base_ref
))
557 base_ref
= TREE_OPERAND (base_ref
, 0);
558 ref
->base_alias_set
= get_alias_set (base_ref
);
559 return ref
->base_alias_set
;
562 /* Returns the reference alias set of the memory reference *REF. */
565 ao_ref_alias_set (ao_ref
*ref
)
567 if (ref
->ref_alias_set
!= -1)
568 return ref
->ref_alias_set
;
569 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
570 return ref
->ref_alias_set
;
573 /* Init an alias-oracle reference representation from a gimple pointer
574 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the
575 size is assumed to be unknown. The access is assumed to be only
576 to or after of the pointer target, not before it. */
579 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
581 HOST_WIDE_INT t
, extra_offset
= 0;
582 ref
->ref
= NULL_TREE
;
583 if (TREE_CODE (ptr
) == SSA_NAME
)
585 gimple stmt
= SSA_NAME_DEF_STMT (ptr
);
586 if (gimple_assign_single_p (stmt
)
587 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
588 ptr
= gimple_assign_rhs1 (stmt
);
589 else if (is_gimple_assign (stmt
)
590 && gimple_assign_rhs_code (stmt
) == POINTER_PLUS_EXPR
591 && TREE_CODE (gimple_assign_rhs2 (stmt
)) == INTEGER_CST
)
593 ptr
= gimple_assign_rhs1 (stmt
);
594 extra_offset
= BITS_PER_UNIT
595 * int_cst_value (gimple_assign_rhs2 (stmt
));
599 if (TREE_CODE (ptr
) == ADDR_EXPR
)
601 ref
->base
= get_addr_base_and_unit_offset (TREE_OPERAND (ptr
, 0), &t
);
603 ref
->offset
= BITS_PER_UNIT
* t
;
608 ref
->base
= get_base_address (TREE_OPERAND (ptr
, 0));
613 ref
->base
= build2 (MEM_REF
, char_type_node
,
614 ptr
, null_pointer_node
);
617 ref
->offset
+= extra_offset
;
619 && tree_fits_shwi_p (size
)
620 && TREE_INT_CST_LOW (size
) * BITS_PER_UNIT
/ BITS_PER_UNIT
621 == TREE_INT_CST_LOW (size
))
622 ref
->max_size
= ref
->size
= TREE_INT_CST_LOW (size
) * BITS_PER_UNIT
;
624 ref
->max_size
= ref
->size
= -1;
625 ref
->ref_alias_set
= 0;
626 ref
->base_alias_set
= 0;
627 ref
->volatile_p
= false;
630 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
631 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
635 same_type_for_tbaa (tree type1
, tree type2
)
637 type1
= TYPE_MAIN_VARIANT (type1
);
638 type2
= TYPE_MAIN_VARIANT (type2
);
640 /* If we would have to do structural comparison bail out. */
641 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
642 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
645 /* Compare the canonical types. */
646 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
649 /* ??? Array types are not properly unified in all cases as we have
650 spurious changes in the index types for example. Removing this
651 causes all sorts of problems with the Fortran frontend. */
652 if (TREE_CODE (type1
) == ARRAY_TYPE
653 && TREE_CODE (type2
) == ARRAY_TYPE
)
656 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
657 object of one of its constrained subtypes, e.g. when a function with an
658 unconstrained parameter passed by reference is called on an object and
659 inlined. But, even in the case of a fixed size, type and subtypes are
660 not equivalent enough as to share the same TYPE_CANONICAL, since this
661 would mean that conversions between them are useless, whereas they are
662 not (e.g. type and subtypes can have different modes). So, in the end,
663 they are only guaranteed to have the same alias set. */
664 if (get_alias_set (type1
) == get_alias_set (type2
))
667 /* The types are known to be not equal. */
671 /* Determine if the two component references REF1 and REF2 which are
672 based on access types TYPE1 and TYPE2 and of which at least one is based
673 on an indirect reference may alias. REF2 is the only one that can
674 be a decl in which case REF2_IS_DECL is true.
675 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
676 are the respective alias sets. */
679 aliasing_component_refs_p (tree ref1
,
680 alias_set_type ref1_alias_set
,
681 alias_set_type base1_alias_set
,
682 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
684 alias_set_type ref2_alias_set
,
685 alias_set_type base2_alias_set
,
686 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
689 /* If one reference is a component references through pointers try to find a
690 common base and apply offset based disambiguation. This handles
692 struct A { int i; int j; } *q;
693 struct B { struct A a; int k; } *p;
694 disambiguating q->i and p->a.j. */
700 /* Choose bases and base types to search for. */
702 while (handled_component_p (base1
))
703 base1
= TREE_OPERAND (base1
, 0);
704 type1
= TREE_TYPE (base1
);
706 while (handled_component_p (base2
))
707 base2
= TREE_OPERAND (base2
, 0);
708 type2
= TREE_TYPE (base2
);
710 /* Now search for the type1 in the access path of ref2. This
711 would be a common base for doing offset based disambiguation on. */
713 while (handled_component_p (*refp
)
714 && same_type_for_tbaa (TREE_TYPE (*refp
), type1
) == 0)
715 refp
= &TREE_OPERAND (*refp
, 0);
716 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
717 /* If we couldn't compare types we have to bail out. */
720 else if (same_p
== 1)
722 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
723 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
725 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
);
727 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
729 /* If we didn't find a common base, try the other way around. */
731 while (handled_component_p (*refp
)
732 && same_type_for_tbaa (TREE_TYPE (*refp
), type2
) == 0)
733 refp
= &TREE_OPERAND (*refp
, 0);
734 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
735 /* If we couldn't compare types we have to bail out. */
738 else if (same_p
== 1)
740 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
741 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
743 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
);
745 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
748 /* If we have two type access paths B1.path1 and B2.path2 they may
749 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
750 But we can still have a path that goes B1.path1...B2.path2 with
751 a part that we do not see. So we can only disambiguate now
752 if there is no B2 in the tail of path1 and no B1 on the
754 if (base1_alias_set
== ref2_alias_set
755 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
))
757 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
759 return (base2_alias_set
== ref1_alias_set
760 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
));
764 /* Return true if we can determine that component references REF1 and REF2,
765 that are within a common DECL, cannot overlap. */
768 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
770 stack_vec
<tree
, 16> component_refs1
;
771 stack_vec
<tree
, 16> component_refs2
;
773 /* Create the stack of handled components for REF1. */
774 while (handled_component_p (ref1
))
776 component_refs1
.safe_push (ref1
);
777 ref1
= TREE_OPERAND (ref1
, 0);
779 if (TREE_CODE (ref1
) == MEM_REF
)
781 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
783 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
786 /* Create the stack of handled components for REF2. */
787 while (handled_component_p (ref2
))
789 component_refs2
.safe_push (ref2
);
790 ref2
= TREE_OPERAND (ref2
, 0);
792 if (TREE_CODE (ref2
) == MEM_REF
)
794 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
796 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
799 /* We must have the same base DECL. */
800 gcc_assert (ref1
== ref2
);
802 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
803 rank. This is sufficient because we start from the same DECL and you
804 cannot reference several fields at a time with COMPONENT_REFs (unlike
805 with ARRAY_RANGE_REFs for arrays) so you always need the same number
806 of them to access a sub-component, unless you're in a union, in which
807 case the return value will precisely be false. */
812 if (component_refs1
.is_empty ())
814 ref1
= component_refs1
.pop ();
816 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
820 if (component_refs2
.is_empty ())
822 ref2
= component_refs2
.pop ();
824 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
826 /* Beware of BIT_FIELD_REF. */
827 if (TREE_CODE (ref1
) != COMPONENT_REF
828 || TREE_CODE (ref2
) != COMPONENT_REF
)
831 tree field1
= TREE_OPERAND (ref1
, 1);
832 tree field2
= TREE_OPERAND (ref2
, 1);
834 /* ??? We cannot simply use the type of operand #0 of the refs here
835 as the Fortran compiler smuggles type punning into COMPONENT_REFs
836 for common blocks instead of using unions like everyone else. */
837 tree type1
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field1
));
838 tree type2
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field2
));
840 /* We cannot disambiguate fields in a union or qualified union. */
841 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
844 /* Different fields of the same record type cannot overlap.
845 ??? Bitfields can overlap at RTL level so punt on them. */
846 if (field1
!= field2
)
848 component_refs1
.release ();
849 component_refs2
.release ();
850 return !(DECL_BIT_FIELD (field1
) && DECL_BIT_FIELD (field2
));
855 component_refs1
.release ();
856 component_refs2
.release ();
860 /* Return true if two memory references based on the variables BASE1
861 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
862 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
863 if non-NULL are the complete memory reference trees. */
866 decl_refs_may_alias_p (tree ref1
, tree base1
,
867 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
868 tree ref2
, tree base2
,
869 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
)
871 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
873 /* If both references are based on different variables, they cannot alias. */
877 /* If both references are based on the same variable, they cannot alias if
878 the accesses do not overlap. */
879 if (!ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
882 /* For components with variable position, the above test isn't sufficient,
883 so we disambiguate component references manually. */
885 && handled_component_p (ref1
) && handled_component_p (ref2
)
886 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
892 /* Return true if an indirect reference based on *PTR1 constrained
893 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
894 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
895 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
896 in which case they are computed on-demand. REF1 and REF2
897 if non-NULL are the complete memory reference trees. */
900 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
901 HOST_WIDE_INT offset1
,
902 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED
,
903 alias_set_type ref1_alias_set
,
904 alias_set_type base1_alias_set
,
905 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
906 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
907 alias_set_type ref2_alias_set
,
908 alias_set_type base2_alias_set
, bool tbaa_p
)
911 tree ptrtype1
, dbase2
;
912 HOST_WIDE_INT offset1p
= offset1
, offset2p
= offset2
;
913 HOST_WIDE_INT doffset1
, doffset2
;
916 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
917 || TREE_CODE (base1
) == TARGET_MEM_REF
)
920 ptr1
= TREE_OPERAND (base1
, 0);
922 /* The offset embedded in MEM_REFs can be negative. Bias them
923 so that the resulting offset adjustment is positive. */
924 moff
= mem_ref_offset (base1
);
925 moff
= moff
.lshift (BITS_PER_UNIT
== 8 ? 3 : exact_log2 (BITS_PER_UNIT
));
926 if (moff
.is_negative ())
927 offset2p
+= (-moff
).low
;
929 offset1p
+= moff
.low
;
931 /* If only one reference is based on a variable, they cannot alias if
932 the pointer access is beyond the extent of the variable access.
933 (the pointer base cannot validly point to an offset less than zero
935 ??? IVOPTs creates bases that do not honor this restriction,
936 so do not apply this optimization for TARGET_MEM_REFs. */
937 if (TREE_CODE (base1
) != TARGET_MEM_REF
938 && !ranges_overlap_p (MAX (0, offset1p
), -1, offset2p
, max_size2
))
940 /* They also cannot alias if the pointer may not point to the decl. */
941 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
944 /* Disambiguations that rely on strict aliasing rules follow. */
945 if (!flag_strict_aliasing
|| !tbaa_p
)
948 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
950 /* If the alias set for a pointer access is zero all bets are off. */
951 if (base1_alias_set
== -1)
952 base1_alias_set
= get_deref_alias_set (ptrtype1
);
953 if (base1_alias_set
== 0)
955 if (base2_alias_set
== -1)
956 base2_alias_set
= get_alias_set (base2
);
958 /* When we are trying to disambiguate an access with a pointer dereference
959 as base versus one with a decl as base we can use both the size
960 of the decl and its dynamic type for extra disambiguation.
961 ??? We do not know anything about the dynamic type of the decl
962 other than that its alias-set contains base2_alias_set as a subset
963 which does not help us here. */
964 /* As we know nothing useful about the dynamic type of the decl just
965 use the usual conflict check rather than a subset test.
966 ??? We could introduce -fvery-strict-aliasing when the language
967 does not allow decls to have a dynamic type that differs from their
968 static type. Then we can check
969 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
970 if (base1_alias_set
!= base2_alias_set
971 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
973 /* If the size of the access relevant for TBAA through the pointer
974 is bigger than the size of the decl we can't possibly access the
975 decl via that pointer. */
976 if (DECL_SIZE (base2
) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1
))
977 && TREE_CODE (DECL_SIZE (base2
)) == INTEGER_CST
978 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1
))) == INTEGER_CST
979 /* ??? This in turn may run afoul when a decl of type T which is
980 a member of union type U is accessed through a pointer to
981 type U and sizeof T is smaller than sizeof U. */
982 && TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
983 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
984 && tree_int_cst_lt (DECL_SIZE (base2
), TYPE_SIZE (TREE_TYPE (ptrtype1
))))
990 /* If the decl is accessed via a MEM_REF, reconstruct the base
991 we can use for TBAA and an appropriately adjusted offset. */
993 while (handled_component_p (dbase2
))
994 dbase2
= TREE_OPERAND (dbase2
, 0);
997 if (TREE_CODE (dbase2
) == MEM_REF
998 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
1000 double_int moff
= mem_ref_offset (dbase2
);
1001 moff
= moff
.lshift (BITS_PER_UNIT
== 8 ? 3 : exact_log2 (BITS_PER_UNIT
));
1002 if (moff
.is_negative ())
1003 doffset1
-= (-moff
).low
;
1005 doffset2
-= moff
.low
;
1008 /* If either reference is view-converted, give up now. */
1009 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
1010 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
1013 /* If both references are through the same type, they do not alias
1014 if the accesses do not overlap. This does extra disambiguation
1015 for mixed/pointer accesses but requires strict aliasing.
1016 For MEM_REFs we require that the component-ref offset we computed
1017 is relative to the start of the type which we ensure by
1018 comparing rvalue and access type and disregarding the constant
1020 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1021 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1022 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
1023 return ranges_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
1025 /* Do access-path based disambiguation. */
1027 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
1028 return aliasing_component_refs_p (ref1
,
1029 ref1_alias_set
, base1_alias_set
,
1032 ref2_alias_set
, base2_alias_set
,
1033 offset2
, max_size2
, true);
1038 /* Return true if two indirect references based on *PTR1
1039 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1040 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1041 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1042 in which case they are computed on-demand. REF1 and REF2
1043 if non-NULL are the complete memory reference trees. */
1046 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1047 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
1048 alias_set_type ref1_alias_set
,
1049 alias_set_type base1_alias_set
,
1050 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1051 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
1052 alias_set_type ref2_alias_set
,
1053 alias_set_type base2_alias_set
, bool tbaa_p
)
1057 tree ptrtype1
, ptrtype2
;
1059 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1060 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1061 && (TREE_CODE (base2
) == MEM_REF
1062 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1064 ptr1
= TREE_OPERAND (base1
, 0);
1065 ptr2
= TREE_OPERAND (base2
, 0);
1067 /* If both bases are based on pointers they cannot alias if they may not
1068 point to the same memory object or if they point to the same object
1069 and the accesses do not overlap. */
1070 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1071 && operand_equal_p (ptr1
, ptr2
, 0)
1072 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1073 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1074 && (TREE_CODE (base2
) != TARGET_MEM_REF
1075 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1076 || (TREE_CODE (base1
) == TARGET_MEM_REF
1077 && TREE_CODE (base2
) == TARGET_MEM_REF
1078 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1079 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1080 && operand_equal_p (TMR_STEP (base1
),
1081 TMR_STEP (base2
), 0)))
1082 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1083 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1084 && operand_equal_p (TMR_INDEX (base1
),
1085 TMR_INDEX (base2
), 0)))
1086 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1087 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1088 && operand_equal_p (TMR_INDEX2 (base1
),
1089 TMR_INDEX2 (base2
), 0))))))
1092 /* The offset embedded in MEM_REFs can be negative. Bias them
1093 so that the resulting offset adjustment is positive. */
1094 moff
= mem_ref_offset (base1
);
1095 moff
= moff
.lshift (BITS_PER_UNIT
== 8 ? 3 : exact_log2 (BITS_PER_UNIT
));
1096 if (moff
.is_negative ())
1097 offset2
+= (-moff
).low
;
1099 offset1
+= moff
.low
;
1100 moff
= mem_ref_offset (base2
);
1101 moff
= moff
.lshift (BITS_PER_UNIT
== 8 ? 3 : exact_log2 (BITS_PER_UNIT
));
1102 if (moff
.is_negative ())
1103 offset1
+= (-moff
).low
;
1105 offset2
+= moff
.low
;
1106 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1108 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1111 /* Disambiguations that rely on strict aliasing rules follow. */
1112 if (!flag_strict_aliasing
|| !tbaa_p
)
1115 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1116 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1118 /* If the alias set for a pointer access is zero all bets are off. */
1119 if (base1_alias_set
== -1)
1120 base1_alias_set
= get_deref_alias_set (ptrtype1
);
1121 if (base1_alias_set
== 0)
1123 if (base2_alias_set
== -1)
1124 base2_alias_set
= get_deref_alias_set (ptrtype2
);
1125 if (base2_alias_set
== 0)
1128 /* If both references are through the same type, they do not alias
1129 if the accesses do not overlap. This does extra disambiguation
1130 for mixed/pointer accesses but requires strict aliasing. */
1131 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1132 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1133 && (TREE_CODE (base2
) != TARGET_MEM_REF
1134 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1135 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1136 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1137 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1138 TREE_TYPE (ptrtype2
)) == 1)
1139 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1141 /* Do type-based disambiguation. */
1142 if (base1_alias_set
!= base2_alias_set
1143 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1146 /* Do access-path based disambiguation. */
1148 && (handled_component_p (ref1
) || handled_component_p (ref2
))
1149 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1150 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1)
1151 return aliasing_component_refs_p (ref1
,
1152 ref1_alias_set
, base1_alias_set
,
1155 ref2_alias_set
, base2_alias_set
,
1156 offset2
, max_size2
, false);
1161 /* Return true, if the two memory references REF1 and REF2 may alias. */
1164 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1167 HOST_WIDE_INT offset1
= 0, offset2
= 0;
1168 HOST_WIDE_INT max_size1
= -1, max_size2
= -1;
1169 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1171 gcc_checking_assert ((!ref1
->ref
1172 || TREE_CODE (ref1
->ref
) == SSA_NAME
1173 || DECL_P (ref1
->ref
)
1174 || TREE_CODE (ref1
->ref
) == STRING_CST
1175 || handled_component_p (ref1
->ref
)
1176 || TREE_CODE (ref1
->ref
) == MEM_REF
1177 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1179 || TREE_CODE (ref2
->ref
) == SSA_NAME
1180 || DECL_P (ref2
->ref
)
1181 || TREE_CODE (ref2
->ref
) == STRING_CST
1182 || handled_component_p (ref2
->ref
)
1183 || TREE_CODE (ref2
->ref
) == MEM_REF
1184 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1186 /* Decompose the references into their base objects and the access. */
1187 base1
= ao_ref_base (ref1
);
1188 offset1
= ref1
->offset
;
1189 max_size1
= ref1
->max_size
;
1190 base2
= ao_ref_base (ref2
);
1191 offset2
= ref2
->offset
;
1192 max_size2
= ref2
->max_size
;
1194 /* We can end up with registers or constants as bases for example from
1195 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1196 which is seen as a struct copy. */
1197 if (TREE_CODE (base1
) == SSA_NAME
1198 || TREE_CODE (base1
) == CONST_DECL
1199 || TREE_CODE (base1
) == CONSTRUCTOR
1200 || TREE_CODE (base1
) == ADDR_EXPR
1201 || CONSTANT_CLASS_P (base1
)
1202 || TREE_CODE (base2
) == SSA_NAME
1203 || TREE_CODE (base2
) == CONST_DECL
1204 || TREE_CODE (base2
) == CONSTRUCTOR
1205 || TREE_CODE (base2
) == ADDR_EXPR
1206 || CONSTANT_CLASS_P (base2
))
1209 /* We can end up referring to code via function and label decls.
1210 As we likely do not properly track code aliases conservatively
1212 if (TREE_CODE (base1
) == FUNCTION_DECL
1213 || TREE_CODE (base1
) == LABEL_DECL
1214 || TREE_CODE (base2
) == FUNCTION_DECL
1215 || TREE_CODE (base2
) == LABEL_DECL
)
1218 /* Two volatile accesses always conflict. */
1219 if (ref1
->volatile_p
1220 && ref2
->volatile_p
)
1223 /* Defer to simple offset based disambiguation if we have
1224 references based on two decls. Do this before defering to
1225 TBAA to handle must-alias cases in conformance with the
1226 GCC extension of allowing type-punning through unions. */
1227 var1_p
= DECL_P (base1
);
1228 var2_p
= DECL_P (base2
);
1229 if (var1_p
&& var2_p
)
1230 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1231 ref2
->ref
, base2
, offset2
, max_size2
);
1233 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1234 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1235 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1236 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1238 /* Canonicalize the pointer-vs-decl case. */
1239 if (ind1_p
&& var2_p
)
1244 tmp1
= offset1
; offset1
= offset2
; offset2
= tmp1
;
1245 tmp1
= max_size1
; max_size1
= max_size2
; max_size2
= tmp1
;
1246 tmp2
= base1
; base1
= base2
; base2
= tmp2
;
1247 tmp3
= ref1
; ref1
= ref2
; ref2
= tmp3
;
1254 /* First defer to TBAA if possible. */
1256 && flag_strict_aliasing
1257 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1258 ao_ref_alias_set (ref2
)))
1261 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1262 if (var1_p
&& ind2_p
)
1263 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1265 ao_ref_alias_set (ref2
), -1,
1268 ao_ref_alias_set (ref1
),
1269 ao_ref_base_alias_set (ref1
),
1271 else if (ind1_p
&& ind2_p
)
1272 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1274 ao_ref_alias_set (ref1
), -1,
1277 ao_ref_alias_set (ref2
), -1,
1280 /* We really do not want to end up here, but returning true is safe. */
1281 #ifdef ENABLE_CHECKING
1289 refs_may_alias_p (tree ref1
, tree ref2
)
1293 ao_ref_init (&r1
, ref1
);
1294 ao_ref_init (&r2
, ref2
);
1295 res
= refs_may_alias_p_1 (&r1
, &r2
, true);
1297 ++alias_stats
.refs_may_alias_p_may_alias
;
1299 ++alias_stats
.refs_may_alias_p_no_alias
;
1303 /* Returns true if there is a anti-dependence for the STORE that
1304 executes after the LOAD. */
1307 refs_anti_dependent_p (tree load
, tree store
)
1310 ao_ref_init (&r1
, load
);
1311 ao_ref_init (&r2
, store
);
1312 return refs_may_alias_p_1 (&r1
, &r2
, false);
1315 /* Returns true if there is a output dependence for the stores
1316 STORE1 and STORE2. */
1319 refs_output_dependent_p (tree store1
, tree store2
)
1322 ao_ref_init (&r1
, store1
);
1323 ao_ref_init (&r2
, store2
);
1324 return refs_may_alias_p_1 (&r1
, &r2
, false);
1327 /* If the call CALL may use the memory reference REF return true,
1328 otherwise return false. */
1331 ref_maybe_used_by_call_p_1 (gimple call
, ao_ref
*ref
)
1335 int flags
= gimple_call_flags (call
);
1337 /* Const functions without a static chain do not implicitly use memory. */
1338 if (!gimple_call_chain (call
)
1339 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1342 base
= ao_ref_base (ref
);
1346 /* A call that is not without side-effects might involve volatile
1347 accesses and thus conflicts with all other volatile accesses. */
1348 if (ref
->volatile_p
)
1351 /* If the reference is based on a decl that is not aliased the call
1352 cannot possibly use it. */
1354 && !may_be_aliased (base
)
1355 /* But local statics can be used through recursion. */
1356 && !is_global_var (base
))
1359 callee
= gimple_call_fndecl (call
);
1361 /* Handle those builtin functions explicitly that do not act as
1362 escape points. See tree-ssa-structalias.c:find_func_aliases
1363 for the list of builtins we might need to handle here. */
1364 if (callee
!= NULL_TREE
1365 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1366 switch (DECL_FUNCTION_CODE (callee
))
1368 /* All the following functions read memory pointed to by
1369 their second argument. strcat/strncat additionally
1370 reads memory pointed to by the first argument. */
1371 case BUILT_IN_STRCAT
:
1372 case BUILT_IN_STRNCAT
:
1375 ao_ref_init_from_ptr_and_size (&dref
,
1376 gimple_call_arg (call
, 0),
1378 if (refs_may_alias_p_1 (&dref
, ref
, false))
1382 case BUILT_IN_STRCPY
:
1383 case BUILT_IN_STRNCPY
:
1384 case BUILT_IN_MEMCPY
:
1385 case BUILT_IN_MEMMOVE
:
1386 case BUILT_IN_MEMPCPY
:
1387 case BUILT_IN_STPCPY
:
1388 case BUILT_IN_STPNCPY
:
1389 case BUILT_IN_TM_MEMCPY
:
1390 case BUILT_IN_TM_MEMMOVE
:
1393 tree size
= NULL_TREE
;
1394 if (gimple_call_num_args (call
) == 3)
1395 size
= gimple_call_arg (call
, 2);
1396 ao_ref_init_from_ptr_and_size (&dref
,
1397 gimple_call_arg (call
, 1),
1399 return refs_may_alias_p_1 (&dref
, ref
, false);
1401 case BUILT_IN_STRCAT_CHK
:
1402 case BUILT_IN_STRNCAT_CHK
:
1405 ao_ref_init_from_ptr_and_size (&dref
,
1406 gimple_call_arg (call
, 0),
1408 if (refs_may_alias_p_1 (&dref
, ref
, false))
1412 case BUILT_IN_STRCPY_CHK
:
1413 case BUILT_IN_STRNCPY_CHK
:
1414 case BUILT_IN_MEMCPY_CHK
:
1415 case BUILT_IN_MEMMOVE_CHK
:
1416 case BUILT_IN_MEMPCPY_CHK
:
1417 case BUILT_IN_STPCPY_CHK
:
1418 case BUILT_IN_STPNCPY_CHK
:
1421 tree size
= NULL_TREE
;
1422 if (gimple_call_num_args (call
) == 4)
1423 size
= gimple_call_arg (call
, 2);
1424 ao_ref_init_from_ptr_and_size (&dref
,
1425 gimple_call_arg (call
, 1),
1427 return refs_may_alias_p_1 (&dref
, ref
, false);
1429 case BUILT_IN_BCOPY
:
1432 tree size
= gimple_call_arg (call
, 2);
1433 ao_ref_init_from_ptr_and_size (&dref
,
1434 gimple_call_arg (call
, 0),
1436 return refs_may_alias_p_1 (&dref
, ref
, false);
1439 /* The following functions read memory pointed to by their
1441 CASE_BUILT_IN_TM_LOAD (1):
1442 CASE_BUILT_IN_TM_LOAD (2):
1443 CASE_BUILT_IN_TM_LOAD (4):
1444 CASE_BUILT_IN_TM_LOAD (8):
1445 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1446 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1447 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1448 CASE_BUILT_IN_TM_LOAD (M64
):
1449 CASE_BUILT_IN_TM_LOAD (M128
):
1450 CASE_BUILT_IN_TM_LOAD (M256
):
1451 case BUILT_IN_TM_LOG
:
1452 case BUILT_IN_TM_LOG_1
:
1453 case BUILT_IN_TM_LOG_2
:
1454 case BUILT_IN_TM_LOG_4
:
1455 case BUILT_IN_TM_LOG_8
:
1456 case BUILT_IN_TM_LOG_FLOAT
:
1457 case BUILT_IN_TM_LOG_DOUBLE
:
1458 case BUILT_IN_TM_LOG_LDOUBLE
:
1459 case BUILT_IN_TM_LOG_M64
:
1460 case BUILT_IN_TM_LOG_M128
:
1461 case BUILT_IN_TM_LOG_M256
:
1462 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1464 /* These read memory pointed to by the first argument. */
1465 case BUILT_IN_STRDUP
:
1466 case BUILT_IN_STRNDUP
:
1469 tree size
= NULL_TREE
;
1470 if (gimple_call_num_args (call
) == 2)
1471 size
= gimple_call_arg (call
, 1);
1472 ao_ref_init_from_ptr_and_size (&dref
,
1473 gimple_call_arg (call
, 0),
1475 return refs_may_alias_p_1 (&dref
, ref
, false);
1477 /* These read memory pointed to by the first argument. */
1478 case BUILT_IN_INDEX
:
1479 case BUILT_IN_STRCHR
:
1480 case BUILT_IN_STRRCHR
:
1483 ao_ref_init_from_ptr_and_size (&dref
,
1484 gimple_call_arg (call
, 0),
1486 return refs_may_alias_p_1 (&dref
, ref
, false);
1488 /* These read memory pointed to by the first argument with size
1489 in the third argument. */
1490 case BUILT_IN_MEMCHR
:
1493 ao_ref_init_from_ptr_and_size (&dref
,
1494 gimple_call_arg (call
, 0),
1495 gimple_call_arg (call
, 2));
1496 return refs_may_alias_p_1 (&dref
, ref
, false);
1498 /* These read memory pointed to by the first and second arguments. */
1499 case BUILT_IN_STRSTR
:
1500 case BUILT_IN_STRPBRK
:
1503 ao_ref_init_from_ptr_and_size (&dref
,
1504 gimple_call_arg (call
, 0),
1506 if (refs_may_alias_p_1 (&dref
, ref
, false))
1508 ao_ref_init_from_ptr_and_size (&dref
,
1509 gimple_call_arg (call
, 1),
1511 return refs_may_alias_p_1 (&dref
, ref
, false);
1514 /* The following builtins do not read from memory. */
1516 case BUILT_IN_MALLOC
:
1517 case BUILT_IN_CALLOC
:
1518 case BUILT_IN_ALLOCA
:
1519 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1520 case BUILT_IN_STACK_SAVE
:
1521 case BUILT_IN_STACK_RESTORE
:
1522 case BUILT_IN_MEMSET
:
1523 case BUILT_IN_TM_MEMSET
:
1524 case BUILT_IN_MEMSET_CHK
:
1525 case BUILT_IN_FREXP
:
1526 case BUILT_IN_FREXPF
:
1527 case BUILT_IN_FREXPL
:
1528 case BUILT_IN_GAMMA_R
:
1529 case BUILT_IN_GAMMAF_R
:
1530 case BUILT_IN_GAMMAL_R
:
1531 case BUILT_IN_LGAMMA_R
:
1532 case BUILT_IN_LGAMMAF_R
:
1533 case BUILT_IN_LGAMMAL_R
:
1535 case BUILT_IN_MODFF
:
1536 case BUILT_IN_MODFL
:
1537 case BUILT_IN_REMQUO
:
1538 case BUILT_IN_REMQUOF
:
1539 case BUILT_IN_REMQUOL
:
1540 case BUILT_IN_SINCOS
:
1541 case BUILT_IN_SINCOSF
:
1542 case BUILT_IN_SINCOSL
:
1543 case BUILT_IN_ASSUME_ALIGNED
:
1544 case BUILT_IN_VA_END
:
1546 /* __sync_* builtins and some OpenMP builtins act as threading
1548 #undef DEF_SYNC_BUILTIN
1549 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1550 #include "sync-builtins.def"
1551 #undef DEF_SYNC_BUILTIN
1552 case BUILT_IN_GOMP_ATOMIC_START
:
1553 case BUILT_IN_GOMP_ATOMIC_END
:
1554 case BUILT_IN_GOMP_BARRIER
:
1555 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1556 case BUILT_IN_GOMP_TASKWAIT
:
1557 case BUILT_IN_GOMP_TASKGROUP_END
:
1558 case BUILT_IN_GOMP_CRITICAL_START
:
1559 case BUILT_IN_GOMP_CRITICAL_END
:
1560 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1561 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1562 case BUILT_IN_GOMP_LOOP_END
:
1563 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1564 case BUILT_IN_GOMP_ORDERED_START
:
1565 case BUILT_IN_GOMP_ORDERED_END
:
1566 case BUILT_IN_GOMP_SECTIONS_END
:
1567 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1568 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1569 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1573 /* Fallthru to general call handling. */;
1576 /* Check if base is a global static variable that is not read
1578 if (callee
!= NULL_TREE
1579 && TREE_CODE (base
) == VAR_DECL
1580 && TREE_STATIC (base
))
1582 struct cgraph_node
*node
= cgraph_get_node (callee
);
1585 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1586 node yet. We should enforce that there are nodes for all decls in the
1587 IL and remove this check instead. */
1589 && (not_read
= ipa_reference_get_not_read_global (node
))
1590 && bitmap_bit_p (not_read
, DECL_UID (base
)))
1594 /* Check if the base variable is call-used. */
1597 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1600 else if ((TREE_CODE (base
) == MEM_REF
1601 || TREE_CODE (base
) == TARGET_MEM_REF
)
1602 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1604 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1608 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1614 /* Inspect call arguments for passed-by-value aliases. */
1616 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1618 tree op
= gimple_call_arg (call
, i
);
1619 int flags
= gimple_call_arg_flags (call
, i
);
1621 if (flags
& EAF_UNUSED
)
1624 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
1625 op
= TREE_OPERAND (op
, 0);
1627 if (TREE_CODE (op
) != SSA_NAME
1628 && !is_gimple_min_invariant (op
))
1631 ao_ref_init (&r
, op
);
1632 if (refs_may_alias_p_1 (&r
, ref
, true))
1641 ref_maybe_used_by_call_p (gimple call
, tree ref
)
1645 ao_ref_init (&r
, ref
);
1646 res
= ref_maybe_used_by_call_p_1 (call
, &r
);
1648 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
1650 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
1655 /* If the statement STMT may use the memory reference REF return
1656 true, otherwise return false. */
1659 ref_maybe_used_by_stmt_p (gimple stmt
, tree ref
)
1661 if (is_gimple_assign (stmt
))
1665 /* All memory assign statements are single. */
1666 if (!gimple_assign_single_p (stmt
))
1669 rhs
= gimple_assign_rhs1 (stmt
);
1670 if (is_gimple_reg (rhs
)
1671 || is_gimple_min_invariant (rhs
)
1672 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
1675 return refs_may_alias_p (rhs
, ref
);
1677 else if (is_gimple_call (stmt
))
1678 return ref_maybe_used_by_call_p (stmt
, ref
);
1679 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
1681 tree retval
= gimple_return_retval (stmt
);
1684 && TREE_CODE (retval
) != SSA_NAME
1685 && !is_gimple_min_invariant (retval
)
1686 && refs_may_alias_p (retval
, ref
))
1688 /* If ref escapes the function then the return acts as a use. */
1689 base
= get_base_address (ref
);
1692 else if (DECL_P (base
))
1693 return is_global_var (base
);
1694 else if (TREE_CODE (base
) == MEM_REF
1695 || TREE_CODE (base
) == TARGET_MEM_REF
)
1696 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
1703 /* If the call in statement CALL may clobber the memory reference REF
1704 return true, otherwise return false. */
1707 call_may_clobber_ref_p_1 (gimple call
, ao_ref
*ref
)
1712 /* If the call is pure or const it cannot clobber anything. */
1713 if (gimple_call_flags (call
)
1714 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
1717 base
= ao_ref_base (ref
);
1721 if (TREE_CODE (base
) == SSA_NAME
1722 || CONSTANT_CLASS_P (base
))
1725 /* A call that is not without side-effects might involve volatile
1726 accesses and thus conflicts with all other volatile accesses. */
1727 if (ref
->volatile_p
)
1730 /* If the reference is based on a decl that is not aliased the call
1731 cannot possibly clobber it. */
1733 && !may_be_aliased (base
)
1734 /* But local non-readonly statics can be modified through recursion
1735 or the call may implement a threading barrier which we must
1736 treat as may-def. */
1737 && (TREE_READONLY (base
)
1738 || !is_global_var (base
)))
1741 callee
= gimple_call_fndecl (call
);
1743 /* Handle those builtin functions explicitly that do not act as
1744 escape points. See tree-ssa-structalias.c:find_func_aliases
1745 for the list of builtins we might need to handle here. */
1746 if (callee
!= NULL_TREE
1747 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1748 switch (DECL_FUNCTION_CODE (callee
))
1750 /* All the following functions clobber memory pointed to by
1751 their first argument. */
1752 case BUILT_IN_STRCPY
:
1753 case BUILT_IN_STRNCPY
:
1754 case BUILT_IN_MEMCPY
:
1755 case BUILT_IN_MEMMOVE
:
1756 case BUILT_IN_MEMPCPY
:
1757 case BUILT_IN_STPCPY
:
1758 case BUILT_IN_STPNCPY
:
1759 case BUILT_IN_STRCAT
:
1760 case BUILT_IN_STRNCAT
:
1761 case BUILT_IN_MEMSET
:
1762 case BUILT_IN_TM_MEMSET
:
1763 CASE_BUILT_IN_TM_STORE (1):
1764 CASE_BUILT_IN_TM_STORE (2):
1765 CASE_BUILT_IN_TM_STORE (4):
1766 CASE_BUILT_IN_TM_STORE (8):
1767 CASE_BUILT_IN_TM_STORE (FLOAT
):
1768 CASE_BUILT_IN_TM_STORE (DOUBLE
):
1769 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
1770 CASE_BUILT_IN_TM_STORE (M64
):
1771 CASE_BUILT_IN_TM_STORE (M128
):
1772 CASE_BUILT_IN_TM_STORE (M256
):
1773 case BUILT_IN_TM_MEMCPY
:
1774 case BUILT_IN_TM_MEMMOVE
:
1777 tree size
= NULL_TREE
;
1778 /* Don't pass in size for strncat, as the maximum size
1779 is strlen (dest) + n + 1 instead of n, resp.
1780 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1782 if (gimple_call_num_args (call
) == 3
1783 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
1784 size
= gimple_call_arg (call
, 2);
1785 ao_ref_init_from_ptr_and_size (&dref
,
1786 gimple_call_arg (call
, 0),
1788 return refs_may_alias_p_1 (&dref
, ref
, false);
1790 case BUILT_IN_STRCPY_CHK
:
1791 case BUILT_IN_STRNCPY_CHK
:
1792 case BUILT_IN_MEMCPY_CHK
:
1793 case BUILT_IN_MEMMOVE_CHK
:
1794 case BUILT_IN_MEMPCPY_CHK
:
1795 case BUILT_IN_STPCPY_CHK
:
1796 case BUILT_IN_STPNCPY_CHK
:
1797 case BUILT_IN_STRCAT_CHK
:
1798 case BUILT_IN_STRNCAT_CHK
:
1799 case BUILT_IN_MEMSET_CHK
:
1802 tree size
= NULL_TREE
;
1803 /* Don't pass in size for __strncat_chk, as the maximum size
1804 is strlen (dest) + n + 1 instead of n, resp.
1805 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1807 if (gimple_call_num_args (call
) == 4
1808 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
1809 size
= gimple_call_arg (call
, 2);
1810 ao_ref_init_from_ptr_and_size (&dref
,
1811 gimple_call_arg (call
, 0),
1813 return refs_may_alias_p_1 (&dref
, ref
, false);
1815 case BUILT_IN_BCOPY
:
1818 tree size
= gimple_call_arg (call
, 2);
1819 ao_ref_init_from_ptr_and_size (&dref
,
1820 gimple_call_arg (call
, 1),
1822 return refs_may_alias_p_1 (&dref
, ref
, false);
1824 /* Allocating memory does not have any side-effects apart from
1825 being the definition point for the pointer. */
1826 case BUILT_IN_MALLOC
:
1827 case BUILT_IN_CALLOC
:
1828 case BUILT_IN_STRDUP
:
1829 case BUILT_IN_STRNDUP
:
1830 /* Unix98 specifies that errno is set on allocation failure. */
1832 && targetm
.ref_may_alias_errno (ref
))
1835 case BUILT_IN_STACK_SAVE
:
1836 case BUILT_IN_ALLOCA
:
1837 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1838 case BUILT_IN_ASSUME_ALIGNED
:
1840 /* Freeing memory kills the pointed-to memory. More importantly
1841 the call has to serve as a barrier for moving loads and stores
1844 case BUILT_IN_VA_END
:
1846 tree ptr
= gimple_call_arg (call
, 0);
1847 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
1849 case BUILT_IN_GAMMA_R
:
1850 case BUILT_IN_GAMMAF_R
:
1851 case BUILT_IN_GAMMAL_R
:
1852 case BUILT_IN_LGAMMA_R
:
1853 case BUILT_IN_LGAMMAF_R
:
1854 case BUILT_IN_LGAMMAL_R
:
1856 tree out
= gimple_call_arg (call
, 1);
1857 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1859 if (flag_errno_math
)
1863 case BUILT_IN_FREXP
:
1864 case BUILT_IN_FREXPF
:
1865 case BUILT_IN_FREXPL
:
1867 case BUILT_IN_MODFF
:
1868 case BUILT_IN_MODFL
:
1870 tree out
= gimple_call_arg (call
, 1);
1871 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
1873 case BUILT_IN_REMQUO
:
1874 case BUILT_IN_REMQUOF
:
1875 case BUILT_IN_REMQUOL
:
1877 tree out
= gimple_call_arg (call
, 2);
1878 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1880 if (flag_errno_math
)
1884 case BUILT_IN_SINCOS
:
1885 case BUILT_IN_SINCOSF
:
1886 case BUILT_IN_SINCOSL
:
1888 tree sin
= gimple_call_arg (call
, 1);
1889 tree cos
= gimple_call_arg (call
, 2);
1890 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
1891 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
1893 /* __sync_* builtins and some OpenMP builtins act as threading
1895 #undef DEF_SYNC_BUILTIN
1896 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1897 #include "sync-builtins.def"
1898 #undef DEF_SYNC_BUILTIN
1899 case BUILT_IN_GOMP_ATOMIC_START
:
1900 case BUILT_IN_GOMP_ATOMIC_END
:
1901 case BUILT_IN_GOMP_BARRIER
:
1902 case BUILT_IN_GOMP_BARRIER_CANCEL
:
1903 case BUILT_IN_GOMP_TASKWAIT
:
1904 case BUILT_IN_GOMP_TASKGROUP_END
:
1905 case BUILT_IN_GOMP_CRITICAL_START
:
1906 case BUILT_IN_GOMP_CRITICAL_END
:
1907 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1908 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1909 case BUILT_IN_GOMP_LOOP_END
:
1910 case BUILT_IN_GOMP_LOOP_END_CANCEL
:
1911 case BUILT_IN_GOMP_ORDERED_START
:
1912 case BUILT_IN_GOMP_ORDERED_END
:
1913 case BUILT_IN_GOMP_SECTIONS_END
:
1914 case BUILT_IN_GOMP_SECTIONS_END_CANCEL
:
1915 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1916 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1919 /* Fallthru to general call handling. */;
1922 /* Check if base is a global static variable that is not written
1924 if (callee
!= NULL_TREE
1925 && TREE_CODE (base
) == VAR_DECL
1926 && TREE_STATIC (base
))
1928 struct cgraph_node
*node
= cgraph_get_node (callee
);
1932 && (not_written
= ipa_reference_get_not_written_global (node
))
1933 && bitmap_bit_p (not_written
, DECL_UID (base
)))
1937 /* Check if the base variable is call-clobbered. */
1939 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
1940 else if ((TREE_CODE (base
) == MEM_REF
1941 || TREE_CODE (base
) == TARGET_MEM_REF
)
1942 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1944 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1948 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
1954 /* If the call in statement CALL may clobber the memory reference REF
1955 return true, otherwise return false. */
1958 call_may_clobber_ref_p (gimple call
, tree ref
)
1962 ao_ref_init (&r
, ref
);
1963 res
= call_may_clobber_ref_p_1 (call
, &r
);
1965 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
1967 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
1972 /* If the statement STMT may clobber the memory reference REF return true,
1973 otherwise return false. */
1976 stmt_may_clobber_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1978 if (is_gimple_call (stmt
))
1980 tree lhs
= gimple_call_lhs (stmt
);
1982 && TREE_CODE (lhs
) != SSA_NAME
)
1985 ao_ref_init (&r
, lhs
);
1986 if (refs_may_alias_p_1 (ref
, &r
, true))
1990 return call_may_clobber_ref_p_1 (stmt
, ref
);
1992 else if (gimple_assign_single_p (stmt
))
1994 tree lhs
= gimple_assign_lhs (stmt
);
1995 if (TREE_CODE (lhs
) != SSA_NAME
)
1998 ao_ref_init (&r
, lhs
);
1999 return refs_may_alias_p_1 (ref
, &r
, true);
2002 else if (gimple_code (stmt
) == GIMPLE_ASM
)
2009 stmt_may_clobber_ref_p (gimple stmt
, tree ref
)
2012 ao_ref_init (&r
, ref
);
2013 return stmt_may_clobber_ref_p_1 (stmt
, &r
);
2016 /* If STMT kills the memory reference REF return true, otherwise
2020 stmt_kills_ref_p_1 (gimple stmt
, ao_ref
*ref
)
2022 /* For a must-alias check we need to be able to constrain
2023 the access properly.
2024 FIXME: except for BUILTIN_FREE. */
2025 if (!ao_ref_base (ref
)
2026 || ref
->max_size
== -1)
2029 if (gimple_has_lhs (stmt
)
2030 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
2031 /* The assignment is not necessarily carried out if it can throw
2032 and we can catch it in the current function where we could inspect
2034 ??? We only need to care about the RHS throwing. For aggregate
2035 assignments or similar calls and non-call exceptions the LHS
2036 might throw as well. */
2037 && !stmt_can_throw_internal (stmt
))
2039 tree base
, lhs
= gimple_get_lhs (stmt
);
2040 HOST_WIDE_INT size
, offset
, max_size
, ref_offset
= ref
->offset
;
2041 base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
);
2042 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2043 so base == ref->base does not always hold. */
2044 if (base
!= ref
->base
)
2046 /* If both base and ref->base are MEM_REFs, only compare the
2047 first operand, and if the second operand isn't equal constant,
2048 try to add the offsets into offset and ref_offset. */
2049 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2050 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2052 if (!tree_int_cst_equal (TREE_OPERAND (base
, 1),
2053 TREE_OPERAND (ref
->base
, 1)))
2055 double_int off1
= mem_ref_offset (base
);
2056 off1
= off1
.lshift (BITS_PER_UNIT
== 8
2057 ? 3 : exact_log2 (BITS_PER_UNIT
));
2058 off1
= off1
+ double_int::from_shwi (offset
);
2059 double_int off2
= mem_ref_offset (ref
->base
);
2060 off2
= off2
.lshift (BITS_PER_UNIT
== 8
2061 ? 3 : exact_log2 (BITS_PER_UNIT
));
2062 off2
= off2
+ double_int::from_shwi (ref_offset
);
2063 if (off1
.fits_shwi () && off2
.fits_shwi ())
2065 offset
= off1
.to_shwi ();
2066 ref_offset
= off2
.to_shwi ();
2075 /* For a must-alias check we need to be able to constrain
2076 the access properly. */
2077 if (size
!= -1 && size
== max_size
)
2079 if (offset
<= ref_offset
2080 && offset
+ size
>= ref_offset
+ ref
->max_size
)
2085 if (is_gimple_call (stmt
))
2087 tree callee
= gimple_call_fndecl (stmt
);
2088 if (callee
!= NULL_TREE
2089 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
2090 switch (DECL_FUNCTION_CODE (callee
))
2094 tree ptr
= gimple_call_arg (stmt
, 0);
2095 tree base
= ao_ref_base (ref
);
2096 if (base
&& TREE_CODE (base
) == MEM_REF
2097 && TREE_OPERAND (base
, 0) == ptr
)
2102 case BUILT_IN_MEMCPY
:
2103 case BUILT_IN_MEMPCPY
:
2104 case BUILT_IN_MEMMOVE
:
2105 case BUILT_IN_MEMSET
:
2106 case BUILT_IN_MEMCPY_CHK
:
2107 case BUILT_IN_MEMPCPY_CHK
:
2108 case BUILT_IN_MEMMOVE_CHK
:
2109 case BUILT_IN_MEMSET_CHK
:
2111 tree dest
= gimple_call_arg (stmt
, 0);
2112 tree len
= gimple_call_arg (stmt
, 2);
2113 if (!tree_fits_shwi_p (len
))
2115 tree rbase
= ref
->base
;
2116 double_int roffset
= double_int::from_shwi (ref
->offset
);
2118 ao_ref_init_from_ptr_and_size (&dref
, dest
, len
);
2119 tree base
= ao_ref_base (&dref
);
2120 double_int offset
= double_int::from_shwi (dref
.offset
);
2121 double_int bpu
= double_int::from_uhwi (BITS_PER_UNIT
);
2122 if (!base
|| dref
.size
== -1)
2124 if (TREE_CODE (base
) == MEM_REF
)
2126 if (TREE_CODE (rbase
) != MEM_REF
)
2128 // Compare pointers.
2129 offset
+= bpu
* mem_ref_offset (base
);
2130 roffset
+= bpu
* mem_ref_offset (rbase
);
2131 base
= TREE_OPERAND (base
, 0);
2132 rbase
= TREE_OPERAND (rbase
, 0);
2136 double_int size
= bpu
* tree_to_double_int (len
);
2137 double_int rsize
= double_int::from_uhwi (ref
->max_size
);
2138 if (offset
.sle (roffset
)
2139 && (roffset
+ rsize
).sle (offset
+ size
))
2145 case BUILT_IN_VA_END
:
2147 tree ptr
= gimple_call_arg (stmt
, 0);
2148 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2150 tree base
= ao_ref_base (ref
);
2151 if (TREE_OPERAND (ptr
, 0) == base
)
2164 stmt_kills_ref_p (gimple stmt
, tree ref
)
2167 ao_ref_init (&r
, ref
);
2168 return stmt_kills_ref_p_1 (stmt
, &r
);
2172 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2173 TARGET or a statement clobbering the memory reference REF in which
2174 case false is returned. The walk starts with VUSE, one argument of PHI. */
2177 maybe_skip_until (gimple phi
, tree target
, ao_ref
*ref
,
2178 tree vuse
, unsigned int *cnt
, bitmap
*visited
,
2179 bool abort_on_visited
)
2181 basic_block bb
= gimple_bb (phi
);
2184 *visited
= BITMAP_ALLOC (NULL
);
2186 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2188 /* Walk until we hit the target. */
2189 while (vuse
!= target
)
2191 gimple def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2192 /* Recurse for PHI nodes. */
2193 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2195 /* An already visited PHI node ends the walk successfully. */
2196 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2197 return !abort_on_visited
;
2198 vuse
= get_continuation_for_phi (def_stmt
, ref
, cnt
,
2199 visited
, abort_on_visited
);
2204 else if (gimple_nop_p (def_stmt
))
2208 /* A clobbering statement or the end of the IL ends it failing. */
2210 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2213 /* If we reach a new basic-block see if we already skipped it
2214 in a previous walk that ended successfully. */
2215 if (gimple_bb (def_stmt
) != bb
)
2217 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2218 return !abort_on_visited
;
2219 bb
= gimple_bb (def_stmt
);
2221 vuse
= gimple_vuse (def_stmt
);
2226 /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
2227 until we hit the phi argument definition that dominates the other one.
2228 Return that, or NULL_TREE if there is no such definition. */
2231 get_continuation_for_phi_1 (gimple phi
, tree arg0
, tree arg1
,
2232 ao_ref
*ref
, unsigned int *cnt
,
2233 bitmap
*visited
, bool abort_on_visited
)
2235 gimple def0
= SSA_NAME_DEF_STMT (arg0
);
2236 gimple def1
= SSA_NAME_DEF_STMT (arg1
);
2241 else if (gimple_nop_p (def0
)
2242 || (!gimple_nop_p (def1
)
2243 && dominated_by_p (CDI_DOMINATORS
,
2244 gimple_bb (def1
), gimple_bb (def0
))))
2246 if (maybe_skip_until (phi
, arg0
, ref
, arg1
, cnt
,
2247 visited
, abort_on_visited
))
2250 else if (gimple_nop_p (def1
)
2251 || dominated_by_p (CDI_DOMINATORS
,
2252 gimple_bb (def0
), gimple_bb (def1
)))
2254 if (maybe_skip_until (phi
, arg1
, ref
, arg0
, cnt
,
2255 visited
, abort_on_visited
))
2258 /* Special case of a diamond:
2260 goto (cond) ? L1 : L2
2261 L1: store1 = ... #MEM_2 = vuse(MEM_1)
2263 L2: store2 = ... #MEM_3 = vuse(MEM_1)
2264 L3: MEM_4 = PHI<MEM_2, MEM_3>
2265 We were called with the PHI at L3, MEM_2 and MEM_3 don't
2266 dominate each other, but still we can easily skip this PHI node
2267 if we recognize that the vuse MEM operand is the same for both,
2268 and that we can skip both statements (they don't clobber us).
2269 This is still linear. Don't use maybe_skip_until, that might
2270 potentially be slow. */
2271 else if ((common_vuse
= gimple_vuse (def0
))
2272 && common_vuse
== gimple_vuse (def1
))
2275 if (!stmt_may_clobber_ref_p_1 (def0
, ref
)
2276 && !stmt_may_clobber_ref_p_1 (def1
, ref
))
2284 /* Starting from a PHI node for the virtual operand of the memory reference
2285 REF find a continuation virtual operand that allows to continue walking
2286 statements dominating PHI skipping only statements that cannot possibly
2287 clobber REF. Increments *CNT for each alias disambiguation done.
2288 Returns NULL_TREE if no suitable virtual operand can be found. */
2291 get_continuation_for_phi (gimple phi
, ao_ref
*ref
,
2292 unsigned int *cnt
, bitmap
*visited
,
2293 bool abort_on_visited
)
2295 unsigned nargs
= gimple_phi_num_args (phi
);
2297 /* Through a single-argument PHI we can simply look through. */
2299 return PHI_ARG_DEF (phi
, 0);
2301 /* For two or more arguments try to pairwise skip non-aliasing code
2302 until we hit the phi argument definition that dominates the other one. */
2303 else if (nargs
>= 2)
2308 /* Find a candidate for the virtual operand which definition
2309 dominates those of all others. */
2310 arg0
= PHI_ARG_DEF (phi
, 0);
2311 if (!SSA_NAME_IS_DEFAULT_DEF (arg0
))
2312 for (i
= 1; i
< nargs
; ++i
)
2314 arg1
= PHI_ARG_DEF (phi
, i
);
2315 if (SSA_NAME_IS_DEFAULT_DEF (arg1
))
2320 if (dominated_by_p (CDI_DOMINATORS
,
2321 gimple_bb (SSA_NAME_DEF_STMT (arg0
)),
2322 gimple_bb (SSA_NAME_DEF_STMT (arg1
))))
2326 /* Then pairwise reduce against the found candidate. */
2327 for (i
= 0; i
< nargs
; ++i
)
2329 arg1
= PHI_ARG_DEF (phi
, i
);
2330 arg0
= get_continuation_for_phi_1 (phi
, arg0
, arg1
, ref
,
2331 cnt
, visited
, abort_on_visited
);
2342 /* Based on the memory reference REF and its virtual use VUSE call
2343 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2344 itself. That is, for each virtual use for which its defining statement
2345 does not clobber REF.
2347 WALKER is called with REF, the current virtual use and DATA. If
2348 WALKER returns non-NULL the walk stops and its result is returned.
2349 At the end of a non-successful walk NULL is returned.
2351 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2352 use which definition is a statement that may clobber REF and DATA.
2353 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2354 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2355 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2356 to adjust REF and *DATA to make that valid.
2358 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2361 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2362 void *(*walker
)(ao_ref
*, tree
, unsigned int, void *),
2363 void *(*translate
)(ao_ref
*, tree
, void *), void *data
)
2365 bitmap visited
= NULL
;
2367 unsigned int cnt
= 0;
2368 bool translated
= false;
2370 timevar_push (TV_ALIAS_STMT_WALK
);
2376 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2377 res
= (*walker
) (ref
, vuse
, cnt
, data
);
2379 if (res
== (void *)-1)
2384 /* Lookup succeeded. */
2385 else if (res
!= NULL
)
2388 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2389 if (gimple_nop_p (def_stmt
))
2391 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2392 vuse
= get_continuation_for_phi (def_stmt
, ref
, &cnt
,
2393 &visited
, translated
);
2397 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2401 res
= (*translate
) (ref
, vuse
, data
);
2402 /* Failed lookup and translation. */
2403 if (res
== (void *)-1)
2408 /* Lookup succeeded. */
2409 else if (res
!= NULL
)
2411 /* Translation succeeded, continue walking. */
2414 vuse
= gimple_vuse (def_stmt
);
2420 BITMAP_FREE (visited
);
2422 timevar_pop (TV_ALIAS_STMT_WALK
);
2428 /* Based on the memory reference REF call WALKER for each vdef which
2429 defining statement may clobber REF, starting with VDEF. If REF
2430 is NULL_TREE, each defining statement is visited.
2432 WALKER is called with REF, the current vdef and DATA. If WALKER
2433 returns true the walk is stopped, otherwise it continues.
2435 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2436 PHI argument (but only one walk continues on merge points), the
2437 return value is true if any of the walks was successful.
2439 The function returns the number of statements walked. */
2442 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
2443 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2444 bitmap
*visited
, unsigned int cnt
)
2448 gimple def_stmt
= SSA_NAME_DEF_STMT (vdef
);
2451 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
2454 if (gimple_nop_p (def_stmt
))
2456 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2460 *visited
= BITMAP_ALLOC (NULL
);
2461 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
2462 cnt
+= walk_aliased_vdefs_1 (ref
, gimple_phi_arg_def (def_stmt
, i
),
2463 walker
, data
, visited
, 0);
2467 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2470 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2471 && (*walker
) (ref
, vdef
, data
))
2474 vdef
= gimple_vuse (def_stmt
);
2480 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
2481 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2484 bitmap local_visited
= NULL
;
2487 timevar_push (TV_ALIAS_STMT_WALK
);
2489 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
2490 visited
? visited
: &local_visited
, 0);
2492 BITMAP_FREE (local_visited
);
2494 timevar_pop (TV_ALIAS_STMT_WALK
);