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 "tree-flow.h"
38 #include "tree-inline.h"
42 #include "pointer-set.h"
43 #include "alloc-pool.h"
44 #include "tree-ssa-alias.h"
46 /* Broad overview of how alias analysis on gimple works:
48 Statements clobbering or using memory are linked through the
49 virtual operand factored use-def chain. The virtual operand
50 is unique per function, its symbol is accessible via gimple_vop (cfun).
51 Virtual operands are used for efficiently walking memory statements
52 in the gimple IL and are useful for things like value-numbering as
53 a generation count for memory references.
55 SSA_NAME pointers may have associated points-to information
56 accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive
57 points-to information is (re-)computed by the TODO_rebuild_alias
58 pass manager todo. Points-to information is also used for more
59 precise tracking of call-clobbered and call-used variables and
60 related disambiguations.
62 This file contains functions for disambiguating memory references,
63 the so called alias-oracle and tools for walking of the gimple IL.
65 The main alias-oracle entry-points are
67 bool stmt_may_clobber_ref_p (gimple, tree)
69 This function queries if a statement may invalidate (parts of)
70 the memory designated by the reference tree argument.
72 bool ref_maybe_used_by_stmt_p (gimple, tree)
74 This function queries if a statement may need (parts of) the
75 memory designated by the reference tree argument.
77 There are variants of these functions that only handle the call
78 part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p.
79 Note that these do not disambiguate against a possible call lhs.
81 bool refs_may_alias_p (tree, tree)
83 This function tries to disambiguate two reference trees.
85 bool ptr_deref_may_alias_global_p (tree)
87 This function queries if dereferencing a pointer variable may
90 More low-level disambiguators are available and documented in
91 this file. Low-level disambiguators dealing with points-to
92 information are in tree-ssa-structalias.c. */
95 /* Query statistics for the different low-level disambiguators.
96 A high-level query may trigger multiple of them. */
99 unsigned HOST_WIDE_INT refs_may_alias_p_may_alias
;
100 unsigned HOST_WIDE_INT refs_may_alias_p_no_alias
;
101 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias
;
102 unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias
;
103 unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias
;
104 unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias
;
108 dump_alias_stats (FILE *s
)
110 fprintf (s
, "\nAlias oracle query stats:\n");
111 fprintf (s
, " refs_may_alias_p: "
112 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
113 HOST_WIDE_INT_PRINT_DEC
" queries\n",
114 alias_stats
.refs_may_alias_p_no_alias
,
115 alias_stats
.refs_may_alias_p_no_alias
116 + alias_stats
.refs_may_alias_p_may_alias
);
117 fprintf (s
, " ref_maybe_used_by_call_p: "
118 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
119 HOST_WIDE_INT_PRINT_DEC
" queries\n",
120 alias_stats
.ref_maybe_used_by_call_p_no_alias
,
121 alias_stats
.refs_may_alias_p_no_alias
122 + alias_stats
.ref_maybe_used_by_call_p_may_alias
);
123 fprintf (s
, " call_may_clobber_ref_p: "
124 HOST_WIDE_INT_PRINT_DEC
" disambiguations, "
125 HOST_WIDE_INT_PRINT_DEC
" queries\n",
126 alias_stats
.call_may_clobber_ref_p_no_alias
,
127 alias_stats
.call_may_clobber_ref_p_no_alias
128 + alias_stats
.call_may_clobber_ref_p_may_alias
);
132 /* Return true, if dereferencing PTR may alias with a global variable. */
135 ptr_deref_may_alias_global_p (tree ptr
)
137 struct ptr_info_def
*pi
;
139 /* If we end up with a pointer constant here that may point
141 if (TREE_CODE (ptr
) != SSA_NAME
)
144 pi
= SSA_NAME_PTR_INFO (ptr
);
146 /* If we do not have points-to information for this variable,
151 /* ??? This does not use TBAA to prune globals ptr may not access. */
152 return pt_solution_includes_global (&pi
->pt
);
155 /* Return true if dereferencing PTR may alias DECL.
156 The caller is responsible for applying TBAA to see if PTR
157 may access DECL at all. */
160 ptr_deref_may_alias_decl_p (tree ptr
, tree decl
)
162 struct ptr_info_def
*pi
;
164 /* Conversions are irrelevant for points-to information and
165 data-dependence analysis can feed us those. */
168 /* Anything we do not explicilty handle aliases. */
169 if ((TREE_CODE (ptr
) != SSA_NAME
170 && TREE_CODE (ptr
) != ADDR_EXPR
171 && TREE_CODE (ptr
) != POINTER_PLUS_EXPR
)
172 || !POINTER_TYPE_P (TREE_TYPE (ptr
))
173 || (TREE_CODE (decl
) != VAR_DECL
174 && TREE_CODE (decl
) != PARM_DECL
175 && TREE_CODE (decl
) != RESULT_DECL
))
178 /* Disregard pointer offsetting. */
179 if (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
)
183 ptr
= TREE_OPERAND (ptr
, 0);
185 while (TREE_CODE (ptr
) == POINTER_PLUS_EXPR
);
186 return ptr_deref_may_alias_decl_p (ptr
, decl
);
189 /* ADDR_EXPR pointers either just offset another pointer or directly
190 specify the pointed-to set. */
191 if (TREE_CODE (ptr
) == ADDR_EXPR
)
193 tree base
= get_base_address (TREE_OPERAND (ptr
, 0));
195 && (TREE_CODE (base
) == MEM_REF
196 || TREE_CODE (base
) == TARGET_MEM_REF
))
197 ptr
= TREE_OPERAND (base
, 0);
202 && CONSTANT_CLASS_P (base
))
208 /* Non-aliased variables can not be pointed to. */
209 if (!may_be_aliased (decl
))
212 /* If we do not have useful points-to information for this pointer
213 we cannot disambiguate anything else. */
214 pi
= SSA_NAME_PTR_INFO (ptr
);
218 return pt_solution_includes (&pi
->pt
, decl
);
221 /* Return true if dereferenced PTR1 and PTR2 may alias.
222 The caller is responsible for applying TBAA to see if accesses
223 through PTR1 and PTR2 may conflict at all. */
226 ptr_derefs_may_alias_p (tree ptr1
, tree ptr2
)
228 struct ptr_info_def
*pi1
, *pi2
;
230 /* Conversions are irrelevant for points-to information and
231 data-dependence analysis can feed us those. */
235 /* Disregard pointer offsetting. */
236 if (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
)
240 ptr1
= TREE_OPERAND (ptr1
, 0);
242 while (TREE_CODE (ptr1
) == POINTER_PLUS_EXPR
);
243 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
245 if (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
)
249 ptr2
= TREE_OPERAND (ptr2
, 0);
251 while (TREE_CODE (ptr2
) == POINTER_PLUS_EXPR
);
252 return ptr_derefs_may_alias_p (ptr1
, ptr2
);
255 /* ADDR_EXPR pointers either just offset another pointer or directly
256 specify the pointed-to set. */
257 if (TREE_CODE (ptr1
) == ADDR_EXPR
)
259 tree base
= get_base_address (TREE_OPERAND (ptr1
, 0));
261 && (TREE_CODE (base
) == MEM_REF
262 || TREE_CODE (base
) == TARGET_MEM_REF
))
263 return ptr_derefs_may_alias_p (TREE_OPERAND (base
, 0), ptr2
);
266 return ptr_deref_may_alias_decl_p (ptr2
, base
);
270 if (TREE_CODE (ptr2
) == ADDR_EXPR
)
272 tree base
= get_base_address (TREE_OPERAND (ptr2
, 0));
274 && (TREE_CODE (base
) == MEM_REF
275 || TREE_CODE (base
) == TARGET_MEM_REF
))
276 return ptr_derefs_may_alias_p (ptr1
, TREE_OPERAND (base
, 0));
279 return ptr_deref_may_alias_decl_p (ptr1
, base
);
284 /* From here we require SSA name pointers. Anything else aliases. */
285 if (TREE_CODE (ptr1
) != SSA_NAME
286 || TREE_CODE (ptr2
) != SSA_NAME
287 || !POINTER_TYPE_P (TREE_TYPE (ptr1
))
288 || !POINTER_TYPE_P (TREE_TYPE (ptr2
)))
291 /* We may end up with two empty points-to solutions for two same pointers.
292 In this case we still want to say both pointers alias, so shortcut
297 /* If we do not have useful points-to information for either pointer
298 we cannot disambiguate anything else. */
299 pi1
= SSA_NAME_PTR_INFO (ptr1
);
300 pi2
= SSA_NAME_PTR_INFO (ptr2
);
304 /* ??? This does not use TBAA to prune decls from the intersection
305 that not both pointers may access. */
306 return pt_solutions_intersect (&pi1
->pt
, &pi2
->pt
);
309 /* Return true if dereferencing PTR may alias *REF.
310 The caller is responsible for applying TBAA to see if PTR
311 may access *REF at all. */
314 ptr_deref_may_alias_ref_p_1 (tree ptr
, ao_ref
*ref
)
316 tree base
= ao_ref_base (ref
);
318 if (TREE_CODE (base
) == MEM_REF
319 || TREE_CODE (base
) == TARGET_MEM_REF
)
320 return ptr_derefs_may_alias_p (ptr
, TREE_OPERAND (base
, 0));
321 else if (DECL_P (base
))
322 return ptr_deref_may_alias_decl_p (ptr
, base
);
327 /* Return true whether REF may refer to global memory. */
330 ref_may_alias_global_p (tree ref
)
332 tree base
= get_base_address (ref
);
334 return is_global_var (base
);
335 else if (TREE_CODE (base
) == MEM_REF
336 || TREE_CODE (base
) == TARGET_MEM_REF
)
337 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
341 /* Return true whether STMT may clobber global memory. */
344 stmt_may_clobber_global_p (gimple stmt
)
348 if (!gimple_vdef (stmt
))
351 /* ??? We can ask the oracle whether an artificial pointer
352 dereference with a pointer with points-to information covering
353 all global memory (what about non-address taken memory?) maybe
354 clobbered by this call. As there is at the moment no convenient
355 way of doing that without generating garbage do some manual
357 ??? We could make a NULL ao_ref argument to the various
358 predicates special, meaning any global memory. */
360 switch (gimple_code (stmt
))
363 lhs
= gimple_assign_lhs (stmt
);
364 return (TREE_CODE (lhs
) != SSA_NAME
365 && ref_may_alias_global_p (lhs
));
374 /* Dump alias information on FILE. */
377 dump_alias_info (FILE *file
)
381 = lang_hooks
.decl_printable_name (current_function_decl
, 2);
384 fprintf (file
, "\n\nAlias information for %s\n\n", funcname
);
386 fprintf (file
, "Aliased symbols\n\n");
388 FOR_EACH_LOCAL_DECL (cfun
, i
, var
)
390 if (may_be_aliased (var
))
391 dump_variable (file
, var
);
394 fprintf (file
, "\nCall clobber information\n");
396 fprintf (file
, "\nESCAPED");
397 dump_points_to_solution (file
, &cfun
->gimple_df
->escaped
);
399 fprintf (file
, "\n\nFlow-insensitive points-to information\n\n");
401 for (i
= 1; i
< num_ssa_names
; i
++)
403 tree ptr
= ssa_name (i
);
404 struct ptr_info_def
*pi
;
407 || SSA_NAME_IN_FREE_LIST (ptr
))
410 pi
= SSA_NAME_PTR_INFO (ptr
);
412 dump_points_to_info_for (file
, ptr
);
415 fprintf (file
, "\n");
419 /* Dump alias information on stderr. */
422 debug_alias_info (void)
424 dump_alias_info (stderr
);
428 /* Dump the points-to set *PT into FILE. */
431 dump_points_to_solution (FILE *file
, struct pt_solution
*pt
)
434 fprintf (file
, ", points-to anything");
437 fprintf (file
, ", points-to non-local");
440 fprintf (file
, ", points-to escaped");
443 fprintf (file
, ", points-to unit escaped");
446 fprintf (file
, ", points-to NULL");
450 fprintf (file
, ", points-to vars: ");
451 dump_decl_set (file
, pt
->vars
);
452 if (pt
->vars_contains_global
)
453 fprintf (file
, " (includes global vars)");
458 /* Unified dump function for pt_solution. */
461 debug (pt_solution
&ref
)
463 dump_points_to_solution (stderr
, &ref
);
467 debug (pt_solution
*ptr
)
472 fprintf (stderr
, "<nil>\n");
476 /* Dump points-to information for SSA_NAME PTR into FILE. */
479 dump_points_to_info_for (FILE *file
, tree ptr
)
481 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (ptr
);
483 print_generic_expr (file
, ptr
, dump_flags
);
486 dump_points_to_solution (file
, &pi
->pt
);
488 fprintf (file
, ", points-to anything");
490 fprintf (file
, "\n");
494 /* Dump points-to information for VAR into stderr. */
497 debug_points_to_info_for (tree var
)
499 dump_points_to_info_for (stderr
, var
);
503 /* Initializes the alias-oracle reference representation *R from REF. */
506 ao_ref_init (ao_ref
*r
, tree ref
)
513 r
->ref_alias_set
= -1;
514 r
->base_alias_set
= -1;
515 r
->volatile_p
= ref
? TREE_THIS_VOLATILE (ref
) : false;
518 /* Returns the base object of the memory reference *REF. */
521 ao_ref_base (ao_ref
*ref
)
525 ref
->base
= get_ref_base_and_extent (ref
->ref
, &ref
->offset
, &ref
->size
,
530 /* Returns the base object alias set of the memory reference *REF. */
532 static alias_set_type
533 ao_ref_base_alias_set (ao_ref
*ref
)
536 if (ref
->base_alias_set
!= -1)
537 return ref
->base_alias_set
;
541 while (handled_component_p (base_ref
))
542 base_ref
= TREE_OPERAND (base_ref
, 0);
543 ref
->base_alias_set
= get_alias_set (base_ref
);
544 return ref
->base_alias_set
;
547 /* Returns the reference alias set of the memory reference *REF. */
550 ao_ref_alias_set (ao_ref
*ref
)
552 if (ref
->ref_alias_set
!= -1)
553 return ref
->ref_alias_set
;
554 ref
->ref_alias_set
= get_alias_set (ref
->ref
);
555 return ref
->ref_alias_set
;
558 /* Init an alias-oracle reference representation from a gimple pointer
559 PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE the the
560 size is assumed to be unknown. The access is assumed to be only
561 to or after of the pointer target, not before it. */
564 ao_ref_init_from_ptr_and_size (ao_ref
*ref
, tree ptr
, tree size
)
566 HOST_WIDE_INT t1
, t2
;
567 ref
->ref
= NULL_TREE
;
568 if (TREE_CODE (ptr
) == ADDR_EXPR
)
569 ref
->base
= get_ref_base_and_extent (TREE_OPERAND (ptr
, 0),
570 &ref
->offset
, &t1
, &t2
);
573 ref
->base
= build2 (MEM_REF
, char_type_node
,
574 ptr
, null_pointer_node
);
578 && host_integerp (size
, 0)
579 && TREE_INT_CST_LOW (size
) * 8 / 8 == TREE_INT_CST_LOW (size
))
580 ref
->max_size
= ref
->size
= TREE_INT_CST_LOW (size
) * 8;
582 ref
->max_size
= ref
->size
= -1;
583 ref
->ref_alias_set
= 0;
584 ref
->base_alias_set
= 0;
585 ref
->volatile_p
= false;
588 /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the
589 purpose of TBAA. Return 0 if they are distinct and -1 if we cannot
593 same_type_for_tbaa (tree type1
, tree type2
)
595 type1
= TYPE_MAIN_VARIANT (type1
);
596 type2
= TYPE_MAIN_VARIANT (type2
);
598 /* If we would have to do structural comparison bail out. */
599 if (TYPE_STRUCTURAL_EQUALITY_P (type1
)
600 || TYPE_STRUCTURAL_EQUALITY_P (type2
))
603 /* Compare the canonical types. */
604 if (TYPE_CANONICAL (type1
) == TYPE_CANONICAL (type2
))
607 /* ??? Array types are not properly unified in all cases as we have
608 spurious changes in the index types for example. Removing this
609 causes all sorts of problems with the Fortran frontend. */
610 if (TREE_CODE (type1
) == ARRAY_TYPE
611 && TREE_CODE (type2
) == ARRAY_TYPE
)
614 /* ??? In Ada, an lvalue of an unconstrained type can be used to access an
615 object of one of its constrained subtypes, e.g. when a function with an
616 unconstrained parameter passed by reference is called on an object and
617 inlined. But, even in the case of a fixed size, type and subtypes are
618 not equivalent enough as to share the same TYPE_CANONICAL, since this
619 would mean that conversions between them are useless, whereas they are
620 not (e.g. type and subtypes can have different modes). So, in the end,
621 they are only guaranteed to have the same alias set. */
622 if (get_alias_set (type1
) == get_alias_set (type2
))
625 /* The types are known to be not equal. */
629 /* Determine if the two component references REF1 and REF2 which are
630 based on access types TYPE1 and TYPE2 and of which at least one is based
631 on an indirect reference may alias. REF2 is the only one that can
632 be a decl in which case REF2_IS_DECL is true.
633 REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET
634 are the respective alias sets. */
637 aliasing_component_refs_p (tree ref1
,
638 alias_set_type ref1_alias_set
,
639 alias_set_type base1_alias_set
,
640 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
642 alias_set_type ref2_alias_set
,
643 alias_set_type base2_alias_set
,
644 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
647 /* If one reference is a component references through pointers try to find a
648 common base and apply offset based disambiguation. This handles
650 struct A { int i; int j; } *q;
651 struct B { struct A a; int k; } *p;
652 disambiguating q->i and p->a.j. */
658 /* Choose bases and base types to search for. */
660 while (handled_component_p (base1
))
661 base1
= TREE_OPERAND (base1
, 0);
662 type1
= TREE_TYPE (base1
);
664 while (handled_component_p (base2
))
665 base2
= TREE_OPERAND (base2
, 0);
666 type2
= TREE_TYPE (base2
);
668 /* Now search for the type1 in the access path of ref2. This
669 would be a common base for doing offset based disambiguation on. */
671 while (handled_component_p (*refp
)
672 && same_type_for_tbaa (TREE_TYPE (*refp
), type1
) == 0)
673 refp
= &TREE_OPERAND (*refp
, 0);
674 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type1
);
675 /* If we couldn't compare types we have to bail out. */
678 else if (same_p
== 1)
680 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
681 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
683 get_ref_base_and_extent (base1
, &offadj
, &sztmp
, &msztmp
);
685 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
687 /* If we didn't find a common base, try the other way around. */
689 while (handled_component_p (*refp
)
690 && same_type_for_tbaa (TREE_TYPE (*refp
), type2
) == 0)
691 refp
= &TREE_OPERAND (*refp
, 0);
692 same_p
= same_type_for_tbaa (TREE_TYPE (*refp
), type2
);
693 /* If we couldn't compare types we have to bail out. */
696 else if (same_p
== 1)
698 HOST_WIDE_INT offadj
, sztmp
, msztmp
;
699 get_ref_base_and_extent (*refp
, &offadj
, &sztmp
, &msztmp
);
701 get_ref_base_and_extent (base2
, &offadj
, &sztmp
, &msztmp
);
703 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
706 /* If we have two type access paths B1.path1 and B2.path2 they may
707 only alias if either B1 is in B2.path2 or B2 is in B1.path1.
708 But we can still have a path that goes B1.path1...B2.path2 with
709 a part that we do not see. So we can only disambiguate now
710 if there is no B2 in the tail of path1 and no B1 on the
712 if (base1_alias_set
== ref2_alias_set
713 || alias_set_subset_of (base1_alias_set
, ref2_alias_set
))
715 /* If this is ptr vs. decl then we know there is no ptr ... decl path. */
717 return (base2_alias_set
== ref1_alias_set
718 || alias_set_subset_of (base2_alias_set
, ref1_alias_set
));
722 /* Return true if we can determine that component references REF1 and REF2,
723 that are within a common DECL, cannot overlap. */
726 nonoverlapping_component_refs_of_decl_p (tree ref1
, tree ref2
)
728 vec
<tree
, va_stack
> component_refs1
;
729 vec
<tree
, va_stack
> component_refs2
;
731 vec_stack_alloc (tree
, component_refs1
, 16);
732 vec_stack_alloc (tree
, component_refs2
, 16);
734 /* Create the stack of handled components for REF1. */
735 while (handled_component_p (ref1
))
737 component_refs1
.safe_push (ref1
);
738 ref1
= TREE_OPERAND (ref1
, 0);
740 if (TREE_CODE (ref1
) == MEM_REF
)
742 if (!integer_zerop (TREE_OPERAND (ref1
, 1)))
744 ref1
= TREE_OPERAND (TREE_OPERAND (ref1
, 0), 0);
747 /* Create the stack of handled components for REF2. */
748 while (handled_component_p (ref2
))
750 component_refs2
.safe_push (ref2
);
751 ref2
= TREE_OPERAND (ref2
, 0);
753 if (TREE_CODE (ref2
) == MEM_REF
)
755 if (!integer_zerop (TREE_OPERAND (ref2
, 1)))
757 ref2
= TREE_OPERAND (TREE_OPERAND (ref2
, 0), 0);
760 /* We must have the same base DECL. */
761 gcc_assert (ref1
== ref2
);
763 /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same
764 rank. This is sufficient because we start from the same DECL and you
765 cannot reference several fields at a time with COMPONENT_REFs (unlike
766 with ARRAY_RANGE_REFs for arrays) so you always need the same number
767 of them to access a sub-component, unless you're in a union, in which
768 case the return value will precisely be false. */
773 if (component_refs1
.is_empty ())
775 ref1
= component_refs1
.pop ();
777 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1
, 0))));
781 if (component_refs2
.is_empty ())
783 ref2
= component_refs2
.pop ();
785 while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2
, 0))));
787 /* Beware of BIT_FIELD_REF. */
788 if (TREE_CODE (ref1
) != COMPONENT_REF
789 || TREE_CODE (ref2
) != COMPONENT_REF
)
792 tree field1
= TREE_OPERAND (ref1
, 1);
793 tree field2
= TREE_OPERAND (ref2
, 1);
795 /* ??? We cannot simply use the type of operand #0 of the refs here
796 as the Fortran compiler smuggles type punning into COMPONENT_REFs
797 for common blocks instead of using unions like everyone else. */
798 tree type1
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field1
));
799 tree type2
= TYPE_MAIN_VARIANT (DECL_CONTEXT (field2
));
801 /* We cannot disambiguate fields in a union or qualified union. */
802 if (type1
!= type2
|| TREE_CODE (type1
) != RECORD_TYPE
)
805 /* Different fields of the same record type cannot overlap. */
806 if (field1
!= field2
)
808 component_refs1
.release ();
809 component_refs2
.release ();
815 component_refs1
.release ();
816 component_refs2
.release ();
820 /* Return true if two memory references based on the variables BASE1
821 and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
822 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
823 if non-NULL are the complete memory reference trees. */
826 decl_refs_may_alias_p (tree ref1
, tree base1
,
827 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
828 tree ref2
, tree base2
,
829 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
)
831 gcc_checking_assert (DECL_P (base1
) && DECL_P (base2
));
833 /* If both references are based on different variables, they cannot alias. */
837 /* If both references are based on the same variable, they cannot alias if
838 the accesses do not overlap. */
839 if (!ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
))
842 /* For components with variable position, the above test isn't sufficient,
843 so we disambiguate component references manually. */
845 && handled_component_p (ref1
) && handled_component_p (ref2
)
846 && nonoverlapping_component_refs_of_decl_p (ref1
, ref2
))
852 /* Return true if an indirect reference based on *PTR1 constrained
853 to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2
854 constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have
855 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
856 in which case they are computed on-demand. REF1 and REF2
857 if non-NULL are the complete memory reference trees. */
860 indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
861 HOST_WIDE_INT offset1
,
862 HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED
,
863 alias_set_type ref1_alias_set
,
864 alias_set_type base1_alias_set
,
865 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
866 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
867 alias_set_type ref2_alias_set
,
868 alias_set_type base2_alias_set
, bool tbaa_p
)
871 tree ptrtype1
, dbase2
;
872 HOST_WIDE_INT offset1p
= offset1
, offset2p
= offset2
;
873 HOST_WIDE_INT doffset1
, doffset2
;
876 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
877 || TREE_CODE (base1
) == TARGET_MEM_REF
)
880 ptr1
= TREE_OPERAND (base1
, 0);
882 /* The offset embedded in MEM_REFs can be negative. Bias them
883 so that the resulting offset adjustment is positive. */
884 moff
= mem_ref_offset (base1
);
885 moff
= moff
.alshift (BITS_PER_UNIT
== 8
886 ? 3 : exact_log2 (BITS_PER_UNIT
),
887 HOST_BITS_PER_DOUBLE_INT
);
888 if (moff
.is_negative ())
889 offset2p
+= (-moff
).low
;
891 offset1p
+= moff
.low
;
893 /* If only one reference is based on a variable, they cannot alias if
894 the pointer access is beyond the extent of the variable access.
895 (the pointer base cannot validly point to an offset less than zero
897 ??? IVOPTs creates bases that do not honor this restriction,
898 so do not apply this optimization for TARGET_MEM_REFs. */
899 if (TREE_CODE (base1
) != TARGET_MEM_REF
900 && !ranges_overlap_p (MAX (0, offset1p
), -1, offset2p
, max_size2
))
902 /* They also cannot alias if the pointer may not point to the decl. */
903 if (!ptr_deref_may_alias_decl_p (ptr1
, base2
))
906 /* Disambiguations that rely on strict aliasing rules follow. */
907 if (!flag_strict_aliasing
|| !tbaa_p
)
910 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
912 /* If the alias set for a pointer access is zero all bets are off. */
913 if (base1_alias_set
== -1)
914 base1_alias_set
= get_deref_alias_set (ptrtype1
);
915 if (base1_alias_set
== 0)
917 if (base2_alias_set
== -1)
918 base2_alias_set
= get_alias_set (base2
);
920 /* When we are trying to disambiguate an access with a pointer dereference
921 as base versus one with a decl as base we can use both the size
922 of the decl and its dynamic type for extra disambiguation.
923 ??? We do not know anything about the dynamic type of the decl
924 other than that its alias-set contains base2_alias_set as a subset
925 which does not help us here. */
926 /* As we know nothing useful about the dynamic type of the decl just
927 use the usual conflict check rather than a subset test.
928 ??? We could introduce -fvery-strict-aliasing when the language
929 does not allow decls to have a dynamic type that differs from their
930 static type. Then we can check
931 !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */
932 if (base1_alias_set
!= base2_alias_set
933 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
935 /* If the size of the access relevant for TBAA through the pointer
936 is bigger than the size of the decl we can't possibly access the
937 decl via that pointer. */
938 if (DECL_SIZE (base2
) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1
))
939 && TREE_CODE (DECL_SIZE (base2
)) == INTEGER_CST
940 && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1
))) == INTEGER_CST
941 /* ??? This in turn may run afoul when a decl of type T which is
942 a member of union type U is accessed through a pointer to
943 type U and sizeof T is smaller than sizeof U. */
944 && TREE_CODE (TREE_TYPE (ptrtype1
)) != UNION_TYPE
945 && TREE_CODE (TREE_TYPE (ptrtype1
)) != QUAL_UNION_TYPE
946 && tree_int_cst_lt (DECL_SIZE (base2
), TYPE_SIZE (TREE_TYPE (ptrtype1
))))
952 /* If the decl is accessed via a MEM_REF, reconstruct the base
953 we can use for TBAA and an appropriately adjusted offset. */
955 while (handled_component_p (dbase2
))
956 dbase2
= TREE_OPERAND (dbase2
, 0);
959 if (TREE_CODE (dbase2
) == MEM_REF
960 || TREE_CODE (dbase2
) == TARGET_MEM_REF
)
962 double_int moff
= mem_ref_offset (dbase2
);
963 moff
= moff
.alshift (BITS_PER_UNIT
== 8
964 ? 3 : exact_log2 (BITS_PER_UNIT
),
965 HOST_BITS_PER_DOUBLE_INT
);
966 if (moff
.is_negative ())
967 doffset1
-= (-moff
).low
;
969 doffset2
-= moff
.low
;
972 /* If either reference is view-converted, give up now. */
973 if (same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) != 1
974 || same_type_for_tbaa (TREE_TYPE (dbase2
), TREE_TYPE (base2
)) != 1)
977 /* If both references are through the same type, they do not alias
978 if the accesses do not overlap. This does extra disambiguation
979 for mixed/pointer accesses but requires strict aliasing.
980 For MEM_REFs we require that the component-ref offset we computed
981 is relative to the start of the type which we ensure by
982 comparing rvalue and access type and disregarding the constant
984 if ((TREE_CODE (base1
) != TARGET_MEM_REF
985 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
986 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (dbase2
)) == 1)
987 return ranges_overlap_p (doffset1
, max_size1
, doffset2
, max_size2
);
989 /* Do access-path based disambiguation. */
991 && (handled_component_p (ref1
) || handled_component_p (ref2
)))
992 return aliasing_component_refs_p (ref1
,
993 ref1_alias_set
, base1_alias_set
,
996 ref2_alias_set
, base2_alias_set
,
997 offset2
, max_size2
, true);
1002 /* Return true if two indirect references based on *PTR1
1003 and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
1004 [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have
1005 the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1
1006 in which case they are computed on-demand. REF1 and REF2
1007 if non-NULL are the complete memory reference trees. */
1010 indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED
, tree base1
,
1011 HOST_WIDE_INT offset1
, HOST_WIDE_INT max_size1
,
1012 alias_set_type ref1_alias_set
,
1013 alias_set_type base1_alias_set
,
1014 tree ref2 ATTRIBUTE_UNUSED
, tree base2
,
1015 HOST_WIDE_INT offset2
, HOST_WIDE_INT max_size2
,
1016 alias_set_type ref2_alias_set
,
1017 alias_set_type base2_alias_set
, bool tbaa_p
)
1021 tree ptrtype1
, ptrtype2
;
1023 gcc_checking_assert ((TREE_CODE (base1
) == MEM_REF
1024 || TREE_CODE (base1
) == TARGET_MEM_REF
)
1025 && (TREE_CODE (base2
) == MEM_REF
1026 || TREE_CODE (base2
) == TARGET_MEM_REF
));
1028 ptr1
= TREE_OPERAND (base1
, 0);
1029 ptr2
= TREE_OPERAND (base2
, 0);
1031 /* If both bases are based on pointers they cannot alias if they may not
1032 point to the same memory object or if they point to the same object
1033 and the accesses do not overlap. */
1034 if ((!cfun
|| gimple_in_ssa_p (cfun
))
1035 && operand_equal_p (ptr1
, ptr2
, 0)
1036 && (((TREE_CODE (base1
) != TARGET_MEM_REF
1037 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1038 && (TREE_CODE (base2
) != TARGET_MEM_REF
1039 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
))))
1040 || (TREE_CODE (base1
) == TARGET_MEM_REF
1041 && TREE_CODE (base2
) == TARGET_MEM_REF
1042 && (TMR_STEP (base1
) == TMR_STEP (base2
)
1043 || (TMR_STEP (base1
) && TMR_STEP (base2
)
1044 && operand_equal_p (TMR_STEP (base1
),
1045 TMR_STEP (base2
), 0)))
1046 && (TMR_INDEX (base1
) == TMR_INDEX (base2
)
1047 || (TMR_INDEX (base1
) && TMR_INDEX (base2
)
1048 && operand_equal_p (TMR_INDEX (base1
),
1049 TMR_INDEX (base2
), 0)))
1050 && (TMR_INDEX2 (base1
) == TMR_INDEX2 (base2
)
1051 || (TMR_INDEX2 (base1
) && TMR_INDEX2 (base2
)
1052 && operand_equal_p (TMR_INDEX2 (base1
),
1053 TMR_INDEX2 (base2
), 0))))))
1056 /* The offset embedded in MEM_REFs can be negative. Bias them
1057 so that the resulting offset adjustment is positive. */
1058 moff
= mem_ref_offset (base1
);
1059 moff
= moff
.alshift (BITS_PER_UNIT
== 8
1060 ? 3 : exact_log2 (BITS_PER_UNIT
),
1061 HOST_BITS_PER_DOUBLE_INT
);
1062 if (moff
.is_negative ())
1063 offset2
+= (-moff
).low
;
1065 offset1
+= moff
.low
;
1066 moff
= mem_ref_offset (base2
);
1067 moff
= moff
.alshift (BITS_PER_UNIT
== 8
1068 ? 3 : exact_log2 (BITS_PER_UNIT
),
1069 HOST_BITS_PER_DOUBLE_INT
);
1070 if (moff
.is_negative ())
1071 offset1
+= (-moff
).low
;
1073 offset2
+= moff
.low
;
1074 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1076 if (!ptr_derefs_may_alias_p (ptr1
, ptr2
))
1079 /* Disambiguations that rely on strict aliasing rules follow. */
1080 if (!flag_strict_aliasing
|| !tbaa_p
)
1083 ptrtype1
= TREE_TYPE (TREE_OPERAND (base1
, 1));
1084 ptrtype2
= TREE_TYPE (TREE_OPERAND (base2
, 1));
1086 /* If the alias set for a pointer access is zero all bets are off. */
1087 if (base1_alias_set
== -1)
1088 base1_alias_set
= get_deref_alias_set (ptrtype1
);
1089 if (base1_alias_set
== 0)
1091 if (base2_alias_set
== -1)
1092 base2_alias_set
= get_deref_alias_set (ptrtype2
);
1093 if (base2_alias_set
== 0)
1096 /* If both references are through the same type, they do not alias
1097 if the accesses do not overlap. This does extra disambiguation
1098 for mixed/pointer accesses but requires strict aliasing. */
1099 if ((TREE_CODE (base1
) != TARGET_MEM_REF
1100 || (!TMR_INDEX (base1
) && !TMR_INDEX2 (base1
)))
1101 && (TREE_CODE (base2
) != TARGET_MEM_REF
1102 || (!TMR_INDEX (base2
) && !TMR_INDEX2 (base2
)))
1103 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1104 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1
1105 && same_type_for_tbaa (TREE_TYPE (ptrtype1
),
1106 TREE_TYPE (ptrtype2
)) == 1)
1107 return ranges_overlap_p (offset1
, max_size1
, offset2
, max_size2
);
1109 /* Do type-based disambiguation. */
1110 if (base1_alias_set
!= base2_alias_set
1111 && !alias_sets_conflict_p (base1_alias_set
, base2_alias_set
))
1114 /* Do access-path based disambiguation. */
1116 && (handled_component_p (ref1
) || handled_component_p (ref2
))
1117 && same_type_for_tbaa (TREE_TYPE (base1
), TREE_TYPE (ptrtype1
)) == 1
1118 && same_type_for_tbaa (TREE_TYPE (base2
), TREE_TYPE (ptrtype2
)) == 1)
1119 return aliasing_component_refs_p (ref1
,
1120 ref1_alias_set
, base1_alias_set
,
1123 ref2_alias_set
, base2_alias_set
,
1124 offset2
, max_size2
, false);
1129 /* Return true, if the two memory references REF1 and REF2 may alias. */
1132 refs_may_alias_p_1 (ao_ref
*ref1
, ao_ref
*ref2
, bool tbaa_p
)
1135 HOST_WIDE_INT offset1
= 0, offset2
= 0;
1136 HOST_WIDE_INT max_size1
= -1, max_size2
= -1;
1137 bool var1_p
, var2_p
, ind1_p
, ind2_p
;
1139 gcc_checking_assert ((!ref1
->ref
1140 || TREE_CODE (ref1
->ref
) == SSA_NAME
1141 || DECL_P (ref1
->ref
)
1142 || TREE_CODE (ref1
->ref
) == STRING_CST
1143 || handled_component_p (ref1
->ref
)
1144 || TREE_CODE (ref1
->ref
) == MEM_REF
1145 || TREE_CODE (ref1
->ref
) == TARGET_MEM_REF
)
1147 || TREE_CODE (ref2
->ref
) == SSA_NAME
1148 || DECL_P (ref2
->ref
)
1149 || TREE_CODE (ref2
->ref
) == STRING_CST
1150 || handled_component_p (ref2
->ref
)
1151 || TREE_CODE (ref2
->ref
) == MEM_REF
1152 || TREE_CODE (ref2
->ref
) == TARGET_MEM_REF
));
1154 /* Decompose the references into their base objects and the access. */
1155 base1
= ao_ref_base (ref1
);
1156 offset1
= ref1
->offset
;
1157 max_size1
= ref1
->max_size
;
1158 base2
= ao_ref_base (ref2
);
1159 offset2
= ref2
->offset
;
1160 max_size2
= ref2
->max_size
;
1162 /* We can end up with registers or constants as bases for example from
1163 *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
1164 which is seen as a struct copy. */
1165 if (TREE_CODE (base1
) == SSA_NAME
1166 || TREE_CODE (base1
) == CONST_DECL
1167 || TREE_CODE (base1
) == CONSTRUCTOR
1168 || TREE_CODE (base1
) == ADDR_EXPR
1169 || CONSTANT_CLASS_P (base1
)
1170 || TREE_CODE (base2
) == SSA_NAME
1171 || TREE_CODE (base2
) == CONST_DECL
1172 || TREE_CODE (base2
) == CONSTRUCTOR
1173 || TREE_CODE (base2
) == ADDR_EXPR
1174 || CONSTANT_CLASS_P (base2
))
1177 /* We can end up referring to code via function and label decls.
1178 As we likely do not properly track code aliases conservatively
1180 if (TREE_CODE (base1
) == FUNCTION_DECL
1181 || TREE_CODE (base1
) == LABEL_DECL
1182 || TREE_CODE (base2
) == FUNCTION_DECL
1183 || TREE_CODE (base2
) == LABEL_DECL
)
1186 /* Two volatile accesses always conflict. */
1187 if (ref1
->volatile_p
1188 && ref2
->volatile_p
)
1191 /* Defer to simple offset based disambiguation if we have
1192 references based on two decls. Do this before defering to
1193 TBAA to handle must-alias cases in conformance with the
1194 GCC extension of allowing type-punning through unions. */
1195 var1_p
= DECL_P (base1
);
1196 var2_p
= DECL_P (base2
);
1197 if (var1_p
&& var2_p
)
1198 return decl_refs_may_alias_p (ref1
->ref
, base1
, offset1
, max_size1
,
1199 ref2
->ref
, base2
, offset2
, max_size2
);
1201 ind1_p
= (TREE_CODE (base1
) == MEM_REF
1202 || TREE_CODE (base1
) == TARGET_MEM_REF
);
1203 ind2_p
= (TREE_CODE (base2
) == MEM_REF
1204 || TREE_CODE (base2
) == TARGET_MEM_REF
);
1206 /* Canonicalize the pointer-vs-decl case. */
1207 if (ind1_p
&& var2_p
)
1212 tmp1
= offset1
; offset1
= offset2
; offset2
= tmp1
;
1213 tmp1
= max_size1
; max_size1
= max_size2
; max_size2
= tmp1
;
1214 tmp2
= base1
; base1
= base2
; base2
= tmp2
;
1215 tmp3
= ref1
; ref1
= ref2
; ref2
= tmp3
;
1222 /* First defer to TBAA if possible. */
1224 && flag_strict_aliasing
1225 && !alias_sets_conflict_p (ao_ref_alias_set (ref1
),
1226 ao_ref_alias_set (ref2
)))
1229 /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */
1230 if (var1_p
&& ind2_p
)
1231 return indirect_ref_may_alias_decl_p (ref2
->ref
, base2
,
1233 ao_ref_alias_set (ref2
), -1,
1236 ao_ref_alias_set (ref1
),
1237 ao_ref_base_alias_set (ref1
),
1239 else if (ind1_p
&& ind2_p
)
1240 return indirect_refs_may_alias_p (ref1
->ref
, base1
,
1242 ao_ref_alias_set (ref1
), -1,
1245 ao_ref_alias_set (ref2
), -1,
1248 /* We really do not want to end up here, but returning true is safe. */
1249 #ifdef ENABLE_CHECKING
1257 refs_may_alias_p (tree ref1
, tree ref2
)
1261 ao_ref_init (&r1
, ref1
);
1262 ao_ref_init (&r2
, ref2
);
1263 res
= refs_may_alias_p_1 (&r1
, &r2
, true);
1265 ++alias_stats
.refs_may_alias_p_may_alias
;
1267 ++alias_stats
.refs_may_alias_p_no_alias
;
1271 /* Returns true if there is a anti-dependence for the STORE that
1272 executes after the LOAD. */
1275 refs_anti_dependent_p (tree load
, tree store
)
1278 ao_ref_init (&r1
, load
);
1279 ao_ref_init (&r2
, store
);
1280 return refs_may_alias_p_1 (&r1
, &r2
, false);
1283 /* Returns true if there is a output dependence for the stores
1284 STORE1 and STORE2. */
1287 refs_output_dependent_p (tree store1
, tree store2
)
1290 ao_ref_init (&r1
, store1
);
1291 ao_ref_init (&r2
, store2
);
1292 return refs_may_alias_p_1 (&r1
, &r2
, false);
1295 /* If the call CALL may use the memory reference REF return true,
1296 otherwise return false. */
1299 ref_maybe_used_by_call_p_1 (gimple call
, ao_ref
*ref
)
1303 int flags
= gimple_call_flags (call
);
1305 /* Const functions without a static chain do not implicitly use memory. */
1306 if (!gimple_call_chain (call
)
1307 && (flags
& (ECF_CONST
|ECF_NOVOPS
)))
1310 base
= ao_ref_base (ref
);
1314 /* A call that is not without side-effects might involve volatile
1315 accesses and thus conflicts with all other volatile accesses. */
1316 if (ref
->volatile_p
)
1319 /* If the reference is based on a decl that is not aliased the call
1320 cannot possibly use it. */
1322 && !may_be_aliased (base
)
1323 /* But local statics can be used through recursion. */
1324 && !is_global_var (base
))
1327 callee
= gimple_call_fndecl (call
);
1329 /* Handle those builtin functions explicitly that do not act as
1330 escape points. See tree-ssa-structalias.c:find_func_aliases
1331 for the list of builtins we might need to handle here. */
1332 if (callee
!= NULL_TREE
1333 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1334 switch (DECL_FUNCTION_CODE (callee
))
1336 /* All the following functions read memory pointed to by
1337 their second argument. strcat/strncat additionally
1338 reads memory pointed to by the first argument. */
1339 case BUILT_IN_STRCAT
:
1340 case BUILT_IN_STRNCAT
:
1343 ao_ref_init_from_ptr_and_size (&dref
,
1344 gimple_call_arg (call
, 0),
1346 if (refs_may_alias_p_1 (&dref
, ref
, false))
1350 case BUILT_IN_STRCPY
:
1351 case BUILT_IN_STRNCPY
:
1352 case BUILT_IN_MEMCPY
:
1353 case BUILT_IN_MEMMOVE
:
1354 case BUILT_IN_MEMPCPY
:
1355 case BUILT_IN_STPCPY
:
1356 case BUILT_IN_STPNCPY
:
1357 case BUILT_IN_TM_MEMCPY
:
1358 case BUILT_IN_TM_MEMMOVE
:
1361 tree size
= NULL_TREE
;
1362 if (gimple_call_num_args (call
) == 3)
1363 size
= gimple_call_arg (call
, 2);
1364 ao_ref_init_from_ptr_and_size (&dref
,
1365 gimple_call_arg (call
, 1),
1367 return refs_may_alias_p_1 (&dref
, ref
, false);
1369 case BUILT_IN_STRCAT_CHK
:
1370 case BUILT_IN_STRNCAT_CHK
:
1373 ao_ref_init_from_ptr_and_size (&dref
,
1374 gimple_call_arg (call
, 0),
1376 if (refs_may_alias_p_1 (&dref
, ref
, false))
1380 case BUILT_IN_STRCPY_CHK
:
1381 case BUILT_IN_STRNCPY_CHK
:
1382 case BUILT_IN_MEMCPY_CHK
:
1383 case BUILT_IN_MEMMOVE_CHK
:
1384 case BUILT_IN_MEMPCPY_CHK
:
1385 case BUILT_IN_STPCPY_CHK
:
1386 case BUILT_IN_STPNCPY_CHK
:
1389 tree size
= NULL_TREE
;
1390 if (gimple_call_num_args (call
) == 4)
1391 size
= gimple_call_arg (call
, 2);
1392 ao_ref_init_from_ptr_and_size (&dref
,
1393 gimple_call_arg (call
, 1),
1395 return refs_may_alias_p_1 (&dref
, ref
, false);
1397 case BUILT_IN_BCOPY
:
1400 tree size
= gimple_call_arg (call
, 2);
1401 ao_ref_init_from_ptr_and_size (&dref
,
1402 gimple_call_arg (call
, 0),
1404 return refs_may_alias_p_1 (&dref
, ref
, false);
1407 /* The following functions read memory pointed to by their
1409 CASE_BUILT_IN_TM_LOAD (1):
1410 CASE_BUILT_IN_TM_LOAD (2):
1411 CASE_BUILT_IN_TM_LOAD (4):
1412 CASE_BUILT_IN_TM_LOAD (8):
1413 CASE_BUILT_IN_TM_LOAD (FLOAT
):
1414 CASE_BUILT_IN_TM_LOAD (DOUBLE
):
1415 CASE_BUILT_IN_TM_LOAD (LDOUBLE
):
1416 CASE_BUILT_IN_TM_LOAD (M64
):
1417 CASE_BUILT_IN_TM_LOAD (M128
):
1418 CASE_BUILT_IN_TM_LOAD (M256
):
1419 case BUILT_IN_TM_LOG
:
1420 case BUILT_IN_TM_LOG_1
:
1421 case BUILT_IN_TM_LOG_2
:
1422 case BUILT_IN_TM_LOG_4
:
1423 case BUILT_IN_TM_LOG_8
:
1424 case BUILT_IN_TM_LOG_FLOAT
:
1425 case BUILT_IN_TM_LOG_DOUBLE
:
1426 case BUILT_IN_TM_LOG_LDOUBLE
:
1427 case BUILT_IN_TM_LOG_M64
:
1428 case BUILT_IN_TM_LOG_M128
:
1429 case BUILT_IN_TM_LOG_M256
:
1430 return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call
, 0), ref
);
1432 /* These read memory pointed to by the first argument. */
1433 case BUILT_IN_STRDUP
:
1434 case BUILT_IN_STRNDUP
:
1437 tree size
= NULL_TREE
;
1438 if (gimple_call_num_args (call
) == 2)
1439 size
= gimple_call_arg (call
, 1);
1440 ao_ref_init_from_ptr_and_size (&dref
,
1441 gimple_call_arg (call
, 0),
1443 return refs_may_alias_p_1 (&dref
, ref
, false);
1445 /* These read memory pointed to by the first argument. */
1446 case BUILT_IN_INDEX
:
1447 case BUILT_IN_STRCHR
:
1448 case BUILT_IN_STRRCHR
:
1451 ao_ref_init_from_ptr_and_size (&dref
,
1452 gimple_call_arg (call
, 0),
1454 return refs_may_alias_p_1 (&dref
, ref
, false);
1456 /* These read memory pointed to by the first argument with size
1457 in the third argument. */
1458 case BUILT_IN_MEMCHR
:
1461 ao_ref_init_from_ptr_and_size (&dref
,
1462 gimple_call_arg (call
, 0),
1463 gimple_call_arg (call
, 2));
1464 return refs_may_alias_p_1 (&dref
, ref
, false);
1466 /* These read memory pointed to by the first and second arguments. */
1467 case BUILT_IN_STRSTR
:
1468 case BUILT_IN_STRPBRK
:
1471 ao_ref_init_from_ptr_and_size (&dref
,
1472 gimple_call_arg (call
, 0),
1474 if (refs_may_alias_p_1 (&dref
, ref
, false))
1476 ao_ref_init_from_ptr_and_size (&dref
,
1477 gimple_call_arg (call
, 1),
1479 return refs_may_alias_p_1 (&dref
, ref
, false);
1482 /* The following builtins do not read from memory. */
1484 case BUILT_IN_MALLOC
:
1485 case BUILT_IN_CALLOC
:
1486 case BUILT_IN_ALLOCA
:
1487 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1488 case BUILT_IN_STACK_SAVE
:
1489 case BUILT_IN_STACK_RESTORE
:
1490 case BUILT_IN_MEMSET
:
1491 case BUILT_IN_TM_MEMSET
:
1492 case BUILT_IN_MEMSET_CHK
:
1493 case BUILT_IN_FREXP
:
1494 case BUILT_IN_FREXPF
:
1495 case BUILT_IN_FREXPL
:
1496 case BUILT_IN_GAMMA_R
:
1497 case BUILT_IN_GAMMAF_R
:
1498 case BUILT_IN_GAMMAL_R
:
1499 case BUILT_IN_LGAMMA_R
:
1500 case BUILT_IN_LGAMMAF_R
:
1501 case BUILT_IN_LGAMMAL_R
:
1503 case BUILT_IN_MODFF
:
1504 case BUILT_IN_MODFL
:
1505 case BUILT_IN_REMQUO
:
1506 case BUILT_IN_REMQUOF
:
1507 case BUILT_IN_REMQUOL
:
1508 case BUILT_IN_SINCOS
:
1509 case BUILT_IN_SINCOSF
:
1510 case BUILT_IN_SINCOSL
:
1511 case BUILT_IN_ASSUME_ALIGNED
:
1512 case BUILT_IN_VA_END
:
1514 /* __sync_* builtins and some OpenMP builtins act as threading
1516 #undef DEF_SYNC_BUILTIN
1517 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1518 #include "sync-builtins.def"
1519 #undef DEF_SYNC_BUILTIN
1520 case BUILT_IN_GOMP_ATOMIC_START
:
1521 case BUILT_IN_GOMP_ATOMIC_END
:
1522 case BUILT_IN_GOMP_BARRIER
:
1523 case BUILT_IN_GOMP_TASKWAIT
:
1524 case BUILT_IN_GOMP_CRITICAL_START
:
1525 case BUILT_IN_GOMP_CRITICAL_END
:
1526 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1527 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1528 case BUILT_IN_GOMP_LOOP_END
:
1529 case BUILT_IN_GOMP_ORDERED_START
:
1530 case BUILT_IN_GOMP_ORDERED_END
:
1531 case BUILT_IN_GOMP_PARALLEL_END
:
1532 case BUILT_IN_GOMP_SECTIONS_END
:
1533 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1534 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1538 /* Fallthru to general call handling. */;
1541 /* Check if base is a global static variable that is not read
1543 if (callee
!= NULL_TREE
1544 && TREE_CODE (base
) == VAR_DECL
1545 && TREE_STATIC (base
))
1547 struct cgraph_node
*node
= cgraph_get_node (callee
);
1550 /* FIXME: Callee can be an OMP builtin that does not have a call graph
1551 node yet. We should enforce that there are nodes for all decls in the
1552 IL and remove this check instead. */
1554 && (not_read
= ipa_reference_get_not_read_global (node
))
1555 && bitmap_bit_p (not_read
, DECL_UID (base
)))
1559 /* Check if the base variable is call-used. */
1562 if (pt_solution_includes (gimple_call_use_set (call
), base
))
1565 else if ((TREE_CODE (base
) == MEM_REF
1566 || TREE_CODE (base
) == TARGET_MEM_REF
)
1567 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1569 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1573 if (pt_solutions_intersect (gimple_call_use_set (call
), &pi
->pt
))
1579 /* Inspect call arguments for passed-by-value aliases. */
1581 for (i
= 0; i
< gimple_call_num_args (call
); ++i
)
1583 tree op
= gimple_call_arg (call
, i
);
1584 int flags
= gimple_call_arg_flags (call
, i
);
1586 if (flags
& EAF_UNUSED
)
1589 if (TREE_CODE (op
) == WITH_SIZE_EXPR
)
1590 op
= TREE_OPERAND (op
, 0);
1592 if (TREE_CODE (op
) != SSA_NAME
1593 && !is_gimple_min_invariant (op
))
1596 ao_ref_init (&r
, op
);
1597 if (refs_may_alias_p_1 (&r
, ref
, true))
1606 ref_maybe_used_by_call_p (gimple call
, tree ref
)
1610 ao_ref_init (&r
, ref
);
1611 res
= ref_maybe_used_by_call_p_1 (call
, &r
);
1613 ++alias_stats
.ref_maybe_used_by_call_p_may_alias
;
1615 ++alias_stats
.ref_maybe_used_by_call_p_no_alias
;
1620 /* If the statement STMT may use the memory reference REF return
1621 true, otherwise return false. */
1624 ref_maybe_used_by_stmt_p (gimple stmt
, tree ref
)
1626 if (is_gimple_assign (stmt
))
1630 /* All memory assign statements are single. */
1631 if (!gimple_assign_single_p (stmt
))
1634 rhs
= gimple_assign_rhs1 (stmt
);
1635 if (is_gimple_reg (rhs
)
1636 || is_gimple_min_invariant (rhs
)
1637 || gimple_assign_rhs_code (stmt
) == CONSTRUCTOR
)
1640 return refs_may_alias_p (rhs
, ref
);
1642 else if (is_gimple_call (stmt
))
1643 return ref_maybe_used_by_call_p (stmt
, ref
);
1644 else if (gimple_code (stmt
) == GIMPLE_RETURN
)
1646 tree retval
= gimple_return_retval (stmt
);
1649 && TREE_CODE (retval
) != SSA_NAME
1650 && !is_gimple_min_invariant (retval
)
1651 && refs_may_alias_p (retval
, ref
))
1653 /* If ref escapes the function then the return acts as a use. */
1654 base
= get_base_address (ref
);
1657 else if (DECL_P (base
))
1658 return is_global_var (base
);
1659 else if (TREE_CODE (base
) == MEM_REF
1660 || TREE_CODE (base
) == TARGET_MEM_REF
)
1661 return ptr_deref_may_alias_global_p (TREE_OPERAND (base
, 0));
1668 /* If the call in statement CALL may clobber the memory reference REF
1669 return true, otherwise return false. */
1672 call_may_clobber_ref_p_1 (gimple call
, ao_ref
*ref
)
1677 /* If the call is pure or const it cannot clobber anything. */
1678 if (gimple_call_flags (call
)
1679 & (ECF_PURE
|ECF_CONST
|ECF_LOOPING_CONST_OR_PURE
|ECF_NOVOPS
))
1682 base
= ao_ref_base (ref
);
1686 if (TREE_CODE (base
) == SSA_NAME
1687 || CONSTANT_CLASS_P (base
))
1690 /* A call that is not without side-effects might involve volatile
1691 accesses and thus conflicts with all other volatile accesses. */
1692 if (ref
->volatile_p
)
1695 /* If the reference is based on a decl that is not aliased the call
1696 cannot possibly clobber it. */
1698 && !may_be_aliased (base
)
1699 /* But local non-readonly statics can be modified through recursion
1700 or the call may implement a threading barrier which we must
1701 treat as may-def. */
1702 && (TREE_READONLY (base
)
1703 || !is_global_var (base
)))
1706 callee
= gimple_call_fndecl (call
);
1708 /* Handle those builtin functions explicitly that do not act as
1709 escape points. See tree-ssa-structalias.c:find_func_aliases
1710 for the list of builtins we might need to handle here. */
1711 if (callee
!= NULL_TREE
1712 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
1713 switch (DECL_FUNCTION_CODE (callee
))
1715 /* All the following functions clobber memory pointed to by
1716 their first argument. */
1717 case BUILT_IN_STRCPY
:
1718 case BUILT_IN_STRNCPY
:
1719 case BUILT_IN_MEMCPY
:
1720 case BUILT_IN_MEMMOVE
:
1721 case BUILT_IN_MEMPCPY
:
1722 case BUILT_IN_STPCPY
:
1723 case BUILT_IN_STPNCPY
:
1724 case BUILT_IN_STRCAT
:
1725 case BUILT_IN_STRNCAT
:
1726 case BUILT_IN_MEMSET
:
1727 case BUILT_IN_TM_MEMSET
:
1728 CASE_BUILT_IN_TM_STORE (1):
1729 CASE_BUILT_IN_TM_STORE (2):
1730 CASE_BUILT_IN_TM_STORE (4):
1731 CASE_BUILT_IN_TM_STORE (8):
1732 CASE_BUILT_IN_TM_STORE (FLOAT
):
1733 CASE_BUILT_IN_TM_STORE (DOUBLE
):
1734 CASE_BUILT_IN_TM_STORE (LDOUBLE
):
1735 CASE_BUILT_IN_TM_STORE (M64
):
1736 CASE_BUILT_IN_TM_STORE (M128
):
1737 CASE_BUILT_IN_TM_STORE (M256
):
1738 case BUILT_IN_TM_MEMCPY
:
1739 case BUILT_IN_TM_MEMMOVE
:
1742 tree size
= NULL_TREE
;
1743 /* Don't pass in size for strncat, as the maximum size
1744 is strlen (dest) + n + 1 instead of n, resp.
1745 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1747 if (gimple_call_num_args (call
) == 3
1748 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT
)
1749 size
= gimple_call_arg (call
, 2);
1750 ao_ref_init_from_ptr_and_size (&dref
,
1751 gimple_call_arg (call
, 0),
1753 return refs_may_alias_p_1 (&dref
, ref
, false);
1755 case BUILT_IN_STRCPY_CHK
:
1756 case BUILT_IN_STRNCPY_CHK
:
1757 case BUILT_IN_MEMCPY_CHK
:
1758 case BUILT_IN_MEMMOVE_CHK
:
1759 case BUILT_IN_MEMPCPY_CHK
:
1760 case BUILT_IN_STPCPY_CHK
:
1761 case BUILT_IN_STPNCPY_CHK
:
1762 case BUILT_IN_STRCAT_CHK
:
1763 case BUILT_IN_STRNCAT_CHK
:
1764 case BUILT_IN_MEMSET_CHK
:
1767 tree size
= NULL_TREE
;
1768 /* Don't pass in size for __strncat_chk, as the maximum size
1769 is strlen (dest) + n + 1 instead of n, resp.
1770 n + 1 at dest + strlen (dest), but strlen (dest) isn't
1772 if (gimple_call_num_args (call
) == 4
1773 && DECL_FUNCTION_CODE (callee
) != BUILT_IN_STRNCAT_CHK
)
1774 size
= gimple_call_arg (call
, 2);
1775 ao_ref_init_from_ptr_and_size (&dref
,
1776 gimple_call_arg (call
, 0),
1778 return refs_may_alias_p_1 (&dref
, ref
, false);
1780 case BUILT_IN_BCOPY
:
1783 tree size
= gimple_call_arg (call
, 2);
1784 ao_ref_init_from_ptr_and_size (&dref
,
1785 gimple_call_arg (call
, 1),
1787 return refs_may_alias_p_1 (&dref
, ref
, false);
1789 /* Allocating memory does not have any side-effects apart from
1790 being the definition point for the pointer. */
1791 case BUILT_IN_MALLOC
:
1792 case BUILT_IN_CALLOC
:
1793 case BUILT_IN_STRDUP
:
1794 case BUILT_IN_STRNDUP
:
1795 /* Unix98 specifies that errno is set on allocation failure. */
1797 && targetm
.ref_may_alias_errno (ref
))
1800 case BUILT_IN_STACK_SAVE
:
1801 case BUILT_IN_ALLOCA
:
1802 case BUILT_IN_ALLOCA_WITH_ALIGN
:
1803 case BUILT_IN_ASSUME_ALIGNED
:
1805 /* Freeing memory kills the pointed-to memory. More importantly
1806 the call has to serve as a barrier for moving loads and stores
1809 case BUILT_IN_VA_END
:
1811 tree ptr
= gimple_call_arg (call
, 0);
1812 return ptr_deref_may_alias_ref_p_1 (ptr
, ref
);
1814 case BUILT_IN_GAMMA_R
:
1815 case BUILT_IN_GAMMAF_R
:
1816 case BUILT_IN_GAMMAL_R
:
1817 case BUILT_IN_LGAMMA_R
:
1818 case BUILT_IN_LGAMMAF_R
:
1819 case BUILT_IN_LGAMMAL_R
:
1821 tree out
= gimple_call_arg (call
, 1);
1822 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1824 if (flag_errno_math
)
1828 case BUILT_IN_FREXP
:
1829 case BUILT_IN_FREXPF
:
1830 case BUILT_IN_FREXPL
:
1832 case BUILT_IN_MODFF
:
1833 case BUILT_IN_MODFL
:
1835 tree out
= gimple_call_arg (call
, 1);
1836 return ptr_deref_may_alias_ref_p_1 (out
, ref
);
1838 case BUILT_IN_REMQUO
:
1839 case BUILT_IN_REMQUOF
:
1840 case BUILT_IN_REMQUOL
:
1842 tree out
= gimple_call_arg (call
, 2);
1843 if (ptr_deref_may_alias_ref_p_1 (out
, ref
))
1845 if (flag_errno_math
)
1849 case BUILT_IN_SINCOS
:
1850 case BUILT_IN_SINCOSF
:
1851 case BUILT_IN_SINCOSL
:
1853 tree sin
= gimple_call_arg (call
, 1);
1854 tree cos
= gimple_call_arg (call
, 2);
1855 return (ptr_deref_may_alias_ref_p_1 (sin
, ref
)
1856 || ptr_deref_may_alias_ref_p_1 (cos
, ref
));
1858 /* __sync_* builtins and some OpenMP builtins act as threading
1860 #undef DEF_SYNC_BUILTIN
1861 #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM:
1862 #include "sync-builtins.def"
1863 #undef DEF_SYNC_BUILTIN
1864 case BUILT_IN_GOMP_ATOMIC_START
:
1865 case BUILT_IN_GOMP_ATOMIC_END
:
1866 case BUILT_IN_GOMP_BARRIER
:
1867 case BUILT_IN_GOMP_TASKWAIT
:
1868 case BUILT_IN_GOMP_CRITICAL_START
:
1869 case BUILT_IN_GOMP_CRITICAL_END
:
1870 case BUILT_IN_GOMP_CRITICAL_NAME_START
:
1871 case BUILT_IN_GOMP_CRITICAL_NAME_END
:
1872 case BUILT_IN_GOMP_LOOP_END
:
1873 case BUILT_IN_GOMP_ORDERED_START
:
1874 case BUILT_IN_GOMP_ORDERED_END
:
1875 case BUILT_IN_GOMP_PARALLEL_END
:
1876 case BUILT_IN_GOMP_SECTIONS_END
:
1877 case BUILT_IN_GOMP_SINGLE_COPY_START
:
1878 case BUILT_IN_GOMP_SINGLE_COPY_END
:
1881 /* Fallthru to general call handling. */;
1884 /* Check if base is a global static variable that is not written
1886 if (callee
!= NULL_TREE
1887 && TREE_CODE (base
) == VAR_DECL
1888 && TREE_STATIC (base
))
1890 struct cgraph_node
*node
= cgraph_get_node (callee
);
1894 && (not_written
= ipa_reference_get_not_written_global (node
))
1895 && bitmap_bit_p (not_written
, DECL_UID (base
)))
1899 /* Check if the base variable is call-clobbered. */
1901 return pt_solution_includes (gimple_call_clobber_set (call
), base
);
1902 else if ((TREE_CODE (base
) == MEM_REF
1903 || TREE_CODE (base
) == TARGET_MEM_REF
)
1904 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1906 struct ptr_info_def
*pi
= SSA_NAME_PTR_INFO (TREE_OPERAND (base
, 0));
1910 return pt_solutions_intersect (gimple_call_clobber_set (call
), &pi
->pt
);
1916 /* If the call in statement CALL may clobber the memory reference REF
1917 return true, otherwise return false. */
1920 call_may_clobber_ref_p (gimple call
, tree ref
)
1924 ao_ref_init (&r
, ref
);
1925 res
= call_may_clobber_ref_p_1 (call
, &r
);
1927 ++alias_stats
.call_may_clobber_ref_p_may_alias
;
1929 ++alias_stats
.call_may_clobber_ref_p_no_alias
;
1934 /* If the statement STMT may clobber the memory reference REF return true,
1935 otherwise return false. */
1938 stmt_may_clobber_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1940 if (is_gimple_call (stmt
))
1942 tree lhs
= gimple_call_lhs (stmt
);
1944 && TREE_CODE (lhs
) != SSA_NAME
)
1947 ao_ref_init (&r
, lhs
);
1948 if (refs_may_alias_p_1 (ref
, &r
, true))
1952 return call_may_clobber_ref_p_1 (stmt
, ref
);
1954 else if (gimple_assign_single_p (stmt
))
1956 tree lhs
= gimple_assign_lhs (stmt
);
1957 if (TREE_CODE (lhs
) != SSA_NAME
)
1960 ao_ref_init (&r
, lhs
);
1961 return refs_may_alias_p_1 (ref
, &r
, true);
1964 else if (gimple_code (stmt
) == GIMPLE_ASM
)
1971 stmt_may_clobber_ref_p (gimple stmt
, tree ref
)
1974 ao_ref_init (&r
, ref
);
1975 return stmt_may_clobber_ref_p_1 (stmt
, &r
);
1978 /* If STMT kills the memory reference REF return true, otherwise
1982 stmt_kills_ref_p_1 (gimple stmt
, ao_ref
*ref
)
1984 /* For a must-alias check we need to be able to constrain
1985 the access properly. */
1987 if (ref
->max_size
== -1)
1990 if (gimple_has_lhs (stmt
)
1991 && TREE_CODE (gimple_get_lhs (stmt
)) != SSA_NAME
1992 /* The assignment is not necessarily carried out if it can throw
1993 and we can catch it in the current function where we could inspect
1995 ??? We only need to care about the RHS throwing. For aggregate
1996 assignments or similar calls and non-call exceptions the LHS
1997 might throw as well. */
1998 && !stmt_can_throw_internal (stmt
))
2000 tree base
, lhs
= gimple_get_lhs (stmt
);
2001 HOST_WIDE_INT size
, offset
, max_size
, ref_offset
= ref
->offset
;
2002 base
= get_ref_base_and_extent (lhs
, &offset
, &size
, &max_size
);
2003 /* We can get MEM[symbol: sZ, index: D.8862_1] here,
2004 so base == ref->base does not always hold. */
2005 if (base
!= ref
->base
)
2007 /* If both base and ref->base are MEM_REFs, only compare the
2008 first operand, and if the second operand isn't equal constant,
2009 try to add the offsets into offset and ref_offset. */
2010 if (TREE_CODE (base
) == MEM_REF
&& TREE_CODE (ref
->base
) == MEM_REF
2011 && TREE_OPERAND (base
, 0) == TREE_OPERAND (ref
->base
, 0))
2013 if (!tree_int_cst_equal (TREE_OPERAND (base
, 0),
2014 TREE_OPERAND (ref
->base
, 0)))
2016 double_int off1
= mem_ref_offset (base
);
2017 off1
= off1
.alshift (BITS_PER_UNIT
== 8
2018 ? 3 : exact_log2 (BITS_PER_UNIT
),
2019 HOST_BITS_PER_DOUBLE_INT
);
2020 off1
= off1
+ double_int::from_shwi (offset
);
2021 double_int off2
= mem_ref_offset (ref
->base
);
2022 off2
= off2
.alshift (BITS_PER_UNIT
== 8
2023 ? 3 : exact_log2 (BITS_PER_UNIT
),
2024 HOST_BITS_PER_DOUBLE_INT
);
2025 off2
= off2
+ double_int::from_shwi (ref_offset
);
2026 if (off1
.fits_shwi () && off2
.fits_shwi ())
2028 offset
= off1
.to_shwi ();
2029 ref_offset
= off2
.to_shwi ();
2038 /* For a must-alias check we need to be able to constrain
2039 the access properly. */
2040 if (size
!= -1 && size
== max_size
)
2042 if (offset
<= ref_offset
2043 && offset
+ size
>= ref_offset
+ ref
->max_size
)
2048 if (is_gimple_call (stmt
))
2050 tree callee
= gimple_call_fndecl (stmt
);
2051 if (callee
!= NULL_TREE
2052 && DECL_BUILT_IN_CLASS (callee
) == BUILT_IN_NORMAL
)
2053 switch (DECL_FUNCTION_CODE (callee
))
2055 case BUILT_IN_MEMCPY
:
2056 case BUILT_IN_MEMPCPY
:
2057 case BUILT_IN_MEMMOVE
:
2058 case BUILT_IN_MEMSET
:
2059 case BUILT_IN_MEMCPY_CHK
:
2060 case BUILT_IN_MEMPCPY_CHK
:
2061 case BUILT_IN_MEMMOVE_CHK
:
2062 case BUILT_IN_MEMSET_CHK
:
2064 tree dest
= gimple_call_arg (stmt
, 0);
2065 tree len
= gimple_call_arg (stmt
, 2);
2066 tree base
= NULL_TREE
;
2067 HOST_WIDE_INT offset
= 0;
2068 if (!host_integerp (len
, 0))
2070 if (TREE_CODE (dest
) == ADDR_EXPR
)
2071 base
= get_addr_base_and_unit_offset (TREE_OPERAND (dest
, 0),
2073 else if (TREE_CODE (dest
) == SSA_NAME
)
2076 && base
== ao_ref_base (ref
))
2078 HOST_WIDE_INT size
= TREE_INT_CST_LOW (len
);
2079 if (offset
<= ref
->offset
/ BITS_PER_UNIT
2081 >= ((ref
->offset
+ ref
->max_size
+ BITS_PER_UNIT
- 1)
2088 case BUILT_IN_VA_END
:
2090 tree ptr
= gimple_call_arg (stmt
, 0);
2091 if (TREE_CODE (ptr
) == ADDR_EXPR
)
2093 tree base
= ao_ref_base (ref
);
2094 if (TREE_OPERAND (ptr
, 0) == base
)
2107 stmt_kills_ref_p (gimple stmt
, tree ref
)
2110 ao_ref_init (&r
, ref
);
2111 return stmt_kills_ref_p_1 (stmt
, &r
);
2115 /* Walk the virtual use-def chain of VUSE until hitting the virtual operand
2116 TARGET or a statement clobbering the memory reference REF in which
2117 case false is returned. The walk starts with VUSE, one argument of PHI. */
2120 maybe_skip_until (gimple phi
, tree target
, ao_ref
*ref
,
2121 tree vuse
, unsigned int *cnt
, bitmap
*visited
,
2122 bool abort_on_visited
)
2124 basic_block bb
= gimple_bb (phi
);
2127 *visited
= BITMAP_ALLOC (NULL
);
2129 bitmap_set_bit (*visited
, SSA_NAME_VERSION (PHI_RESULT (phi
)));
2131 /* Walk until we hit the target. */
2132 while (vuse
!= target
)
2134 gimple def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2135 /* Recurse for PHI nodes. */
2136 if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2138 /* An already visited PHI node ends the walk successfully. */
2139 if (bitmap_bit_p (*visited
, SSA_NAME_VERSION (PHI_RESULT (def_stmt
))))
2140 return !abort_on_visited
;
2141 vuse
= get_continuation_for_phi (def_stmt
, ref
, cnt
,
2142 visited
, abort_on_visited
);
2147 else if (gimple_nop_p (def_stmt
))
2151 /* A clobbering statement or the end of the IL ends it failing. */
2153 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2156 /* If we reach a new basic-block see if we already skipped it
2157 in a previous walk that ended successfully. */
2158 if (gimple_bb (def_stmt
) != bb
)
2160 if (!bitmap_set_bit (*visited
, SSA_NAME_VERSION (vuse
)))
2161 return !abort_on_visited
;
2162 bb
= gimple_bb (def_stmt
);
2164 vuse
= gimple_vuse (def_stmt
);
2169 /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code
2170 until we hit the phi argument definition that dominates the other one.
2171 Return that, or NULL_TREE if there is no such definition. */
2174 get_continuation_for_phi_1 (gimple phi
, tree arg0
, tree arg1
,
2175 ao_ref
*ref
, unsigned int *cnt
,
2176 bitmap
*visited
, bool abort_on_visited
)
2178 gimple def0
= SSA_NAME_DEF_STMT (arg0
);
2179 gimple def1
= SSA_NAME_DEF_STMT (arg1
);
2184 else if (gimple_nop_p (def0
)
2185 || (!gimple_nop_p (def1
)
2186 && dominated_by_p (CDI_DOMINATORS
,
2187 gimple_bb (def1
), gimple_bb (def0
))))
2189 if (maybe_skip_until (phi
, arg0
, ref
, arg1
, cnt
,
2190 visited
, abort_on_visited
))
2193 else if (gimple_nop_p (def1
)
2194 || dominated_by_p (CDI_DOMINATORS
,
2195 gimple_bb (def0
), gimple_bb (def1
)))
2197 if (maybe_skip_until (phi
, arg1
, ref
, arg0
, cnt
,
2198 visited
, abort_on_visited
))
2201 /* Special case of a diamond:
2203 goto (cond) ? L1 : L2
2204 L1: store1 = ... #MEM_2 = vuse(MEM_1)
2206 L2: store2 = ... #MEM_3 = vuse(MEM_1)
2207 L3: MEM_4 = PHI<MEM_2, MEM_3>
2208 We were called with the PHI at L3, MEM_2 and MEM_3 don't
2209 dominate each other, but still we can easily skip this PHI node
2210 if we recognize that the vuse MEM operand is the same for both,
2211 and that we can skip both statements (they don't clobber us).
2212 This is still linear. Don't use maybe_skip_until, that might
2213 potentially be slow. */
2214 else if ((common_vuse
= gimple_vuse (def0
))
2215 && common_vuse
== gimple_vuse (def1
))
2218 if (!stmt_may_clobber_ref_p_1 (def0
, ref
)
2219 && !stmt_may_clobber_ref_p_1 (def1
, ref
))
2227 /* Starting from a PHI node for the virtual operand of the memory reference
2228 REF find a continuation virtual operand that allows to continue walking
2229 statements dominating PHI skipping only statements that cannot possibly
2230 clobber REF. Increments *CNT for each alias disambiguation done.
2231 Returns NULL_TREE if no suitable virtual operand can be found. */
2234 get_continuation_for_phi (gimple phi
, ao_ref
*ref
,
2235 unsigned int *cnt
, bitmap
*visited
,
2236 bool abort_on_visited
)
2238 unsigned nargs
= gimple_phi_num_args (phi
);
2240 /* Through a single-argument PHI we can simply look through. */
2242 return PHI_ARG_DEF (phi
, 0);
2244 /* For two or more arguments try to pairwise skip non-aliasing code
2245 until we hit the phi argument definition that dominates the other one. */
2246 else if (nargs
>= 2)
2251 /* Find a candidate for the virtual operand which definition
2252 dominates those of all others. */
2253 arg0
= PHI_ARG_DEF (phi
, 0);
2254 if (!SSA_NAME_IS_DEFAULT_DEF (arg0
))
2255 for (i
= 1; i
< nargs
; ++i
)
2257 arg1
= PHI_ARG_DEF (phi
, i
);
2258 if (SSA_NAME_IS_DEFAULT_DEF (arg1
))
2263 if (dominated_by_p (CDI_DOMINATORS
,
2264 gimple_bb (SSA_NAME_DEF_STMT (arg0
)),
2265 gimple_bb (SSA_NAME_DEF_STMT (arg1
))))
2269 /* Then pairwise reduce against the found candidate. */
2270 for (i
= 0; i
< nargs
; ++i
)
2272 arg1
= PHI_ARG_DEF (phi
, i
);
2273 arg0
= get_continuation_for_phi_1 (phi
, arg0
, arg1
, ref
,
2274 cnt
, visited
, abort_on_visited
);
2285 /* Based on the memory reference REF and its virtual use VUSE call
2286 WALKER for each virtual use that is equivalent to VUSE, including VUSE
2287 itself. That is, for each virtual use for which its defining statement
2288 does not clobber REF.
2290 WALKER is called with REF, the current virtual use and DATA. If
2291 WALKER returns non-NULL the walk stops and its result is returned.
2292 At the end of a non-successful walk NULL is returned.
2294 TRANSLATE if non-NULL is called with a pointer to REF, the virtual
2295 use which definition is a statement that may clobber REF and DATA.
2296 If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
2297 If TRANSLATE returns non-NULL the walk stops and its result is returned.
2298 If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
2299 to adjust REF and *DATA to make that valid.
2301 TODO: Cache the vector of equivalent vuses per ref, vuse pair. */
2304 walk_non_aliased_vuses (ao_ref
*ref
, tree vuse
,
2305 void *(*walker
)(ao_ref
*, tree
, unsigned int, void *),
2306 void *(*translate
)(ao_ref
*, tree
, void *), void *data
)
2308 bitmap visited
= NULL
;
2310 unsigned int cnt
= 0;
2311 bool translated
= false;
2313 timevar_push (TV_ALIAS_STMT_WALK
);
2319 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2320 res
= (*walker
) (ref
, vuse
, cnt
, data
);
2322 if (res
== (void *)-1)
2327 /* Lookup succeeded. */
2328 else if (res
!= NULL
)
2331 def_stmt
= SSA_NAME_DEF_STMT (vuse
);
2332 if (gimple_nop_p (def_stmt
))
2334 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2335 vuse
= get_continuation_for_phi (def_stmt
, ref
, &cnt
,
2336 &visited
, translated
);
2340 if (stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2344 res
= (*translate
) (ref
, vuse
, data
);
2345 /* Failed lookup and translation. */
2346 if (res
== (void *)-1)
2351 /* Lookup succeeded. */
2352 else if (res
!= NULL
)
2354 /* Translation succeeded, continue walking. */
2357 vuse
= gimple_vuse (def_stmt
);
2363 BITMAP_FREE (visited
);
2365 timevar_pop (TV_ALIAS_STMT_WALK
);
2371 /* Based on the memory reference REF call WALKER for each vdef which
2372 defining statement may clobber REF, starting with VDEF. If REF
2373 is NULL_TREE, each defining statement is visited.
2375 WALKER is called with REF, the current vdef and DATA. If WALKER
2376 returns true the walk is stopped, otherwise it continues.
2378 At PHI nodes walk_aliased_vdefs forks into one walk for reach
2379 PHI argument (but only one walk continues on merge points), the
2380 return value is true if any of the walks was successful.
2382 The function returns the number of statements walked. */
2385 walk_aliased_vdefs_1 (ao_ref
*ref
, tree vdef
,
2386 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2387 bitmap
*visited
, unsigned int cnt
)
2391 gimple def_stmt
= SSA_NAME_DEF_STMT (vdef
);
2394 && !bitmap_set_bit (*visited
, SSA_NAME_VERSION (vdef
)))
2397 if (gimple_nop_p (def_stmt
))
2399 else if (gimple_code (def_stmt
) == GIMPLE_PHI
)
2403 *visited
= BITMAP_ALLOC (NULL
);
2404 for (i
= 0; i
< gimple_phi_num_args (def_stmt
); ++i
)
2405 cnt
+= walk_aliased_vdefs_1 (ref
, gimple_phi_arg_def (def_stmt
, i
),
2406 walker
, data
, visited
, 0);
2410 /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */
2413 || stmt_may_clobber_ref_p_1 (def_stmt
, ref
))
2414 && (*walker
) (ref
, vdef
, data
))
2417 vdef
= gimple_vuse (def_stmt
);
2423 walk_aliased_vdefs (ao_ref
*ref
, tree vdef
,
2424 bool (*walker
)(ao_ref
*, tree
, void *), void *data
,
2427 bitmap local_visited
= NULL
;
2430 timevar_push (TV_ALIAS_STMT_WALK
);
2432 ret
= walk_aliased_vdefs_1 (ref
, vdef
, walker
, data
,
2433 visited
? visited
: &local_visited
, 0);
2435 BITMAP_FREE (local_visited
);
2437 timevar_pop (TV_ALIAS_STMT_WALK
);