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re PR middle-end/80222 (may_alias folded away) 

2017-03-28  Richard Biener  <rguenther@suse.de>

	PR middle-end/80222
	* gimple-fold.c (gimple_fold_indirect_ref): Do not touch
	TYPE_REF_CAN_ALIAS_ALL references.
	* fold-const.c (fold_indirect_ref_1): Likewise.

	* g++.dg/pr80222.C: New testcase.

From-SVN: r246527
This commit is contained in:
Richard Biener 2017-03-28 10:10:01 +00:00 committed by Richard Biener
parent 62f96a79f1
commit 737f500a0b
5 changed files with 31 additions and 4 deletions
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7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
2017-03-28 Richard Biener <rguenther@suse.de>
PR middle-end/80222
* gimple-fold.c (gimple_fold_indirect_ref): Do not touch
TYPE_REF_CAN_ALIAS_ALL references.
* fold-const.c (fold_indirect_ref_1): Likewise.
2017-03-28 Martin Liska <mliska@suse.cz>
PR ipa/80104

3
gcc/fold-const.c
View File

@ -14006,7 +14006,8 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0)
STRIP_NOPS (sub);
subtype = TREE_TYPE (sub);
if (!POINTER_TYPE_P (subtype))
if (!POINTER_TYPE_P (subtype)
|| TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (op0)))
return NULL_TREE;
if (TREE_CODE (sub) == ADDR_EXPR)

7
gcc/gimple-fold.c
View File

@ -6539,8 +6539,8 @@ gimple_get_virt_method_for_binfo (HOST_WIDE_INT token, tree known_binfo,
return gimple_get_virt_method_for_vtable (token, v, offset, can_refer);
}
/* Given a pointer value OP0, return a simplified version of an
indirection through OP0, or NULL_TREE if no simplification is
/* Given a pointer value T, return a simplified version of an
indirection through T, or NULL_TREE if no simplification is
possible. Note that the resulting type may be different from
the type pointed to in the sense that it is still compatible
from the langhooks point of view. */
@ -6554,7 +6554,8 @@ gimple_fold_indirect_ref (tree t)
STRIP_NOPS (sub);
subtype = TREE_TYPE (sub);
if (!POINTER_TYPE_P (subtype))
if (!POINTER_TYPE_P (subtype)
|| TYPE_REF_CAN_ALIAS_ALL (ptype))
return NULL_TREE;
if (TREE_CODE (sub) == ADDR_EXPR)

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2017-03-28 Richard Biener <rguenther@suse.de>
PR middle-end/80222
* g++.dg/pr80222.C: New testcase.
2017-03-28 Martin Liska <mliska@suse.cz>
PR ipa/80104

13
gcc/testsuite/g++.dg/pr80222.C Normal file
View File

@ -0,0 +1,13 @@
// { dg-do compile }
// { dg-options "-O2 -fdump-tree-optimized" } */
struct C { int i; }__attribute__((may_alias)) ;
C a, b;
int main()
{
a = static_cast <C&> (b);
}
// { dg-final { scan-tree-dump "{ref-all}\\\)&b\];" "optimized" } } */