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re PR tree-optimization/69776 (Wrong optimization with aliasing)

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2016-02-16  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/69776
	* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Get alias
	sets from caller.
	(indirect_refs_may_alias_p): Likewise.
	(refs_may_alias_p_1): Pass alias sets as from ao_ref.
	* tree-ssa-sccvn.c (vn_reference_lookup): Also adjust vr alias-set
	according to tbaa_p.
	* tree-ssa-dom.c (lookup_avail_expr): Add tbaa_p flag.
	(optimize_stmt): For redundant store discovery do not allow tbaa.

	* gcc.dg/torture/pr69776-2.c: New testcase.

From-SVN: r233453
This commit is contained in:
Richard Biener 2016-02-16 15:00:45 +00:00 committed by Richard Biener
parent 6d87c306c6
commit 87440c298e
6 changed files with 58 additions and 19 deletions
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12
gcc/ChangeLog
View File

@ -1,3 +1,15 @@
2016-02-16 Richard Biener <rguenther@suse.de>
PR tree-optimization/69776
* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Get alias
sets from caller.
(indirect_refs_may_alias_p): Likewise.
(refs_may_alias_p_1): Pass alias sets as from ao_ref.
* tree-ssa-sccvn.c (vn_reference_lookup): Also adjust vr alias-set
according to tbaa_p.
* tree-ssa-dom.c (lookup_avail_expr): Add tbaa_p flag.
(optimize_stmt): For redundant store discovery do not allow tbaa.
2016-02-16 Bernd Schmidt <bschmidt@redhat.com>
PR tree-optimization/69714

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-02-16 Richard Biener <rguenther@suse.de>
PR tree-optimization/69776
* gcc.dg/torture/pr69776-2.c: New testcase.
2016-02-16 Bernd Schmidt <bschmidt@redhat.com>
PR tree-optimization/69714

25
gcc/testsuite/gcc.dg/torture/pr69776-2.c Normal file
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@ -0,0 +1,25 @@
/* { dg-do run } */
/* { dg-additional-options "-fstrict-aliasing" } */
extern void *malloc (__SIZE_TYPE__);
extern void abort (void);
__attribute__((noinline,noclone))
void f(int *qi, double *qd)
{
int i = *qi;
*qd = 0;
*qi = i;
}
int main()
{
int *p = malloc(sizeof(double));
*p = 1;
f(p, (double *)p);
if (*p != 1)
abort();
return 0;
}

22
gcc/tree-ssa-alias.c
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@ -1067,12 +1067,8 @@ indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1));
/* If the alias set for a pointer access is zero all bets are off. */
if (base1_alias_set == -1)
base1_alias_set = get_deref_alias_set (ptrtype1);
if (base1_alias_set == 0)
return true;
if (base2_alias_set == -1)
base2_alias_set = get_alias_set (base2);
/* When we are trying to disambiguate an access with a pointer dereference
as base versus one with a decl as base we can use both the size
@ -1239,13 +1235,8 @@ indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1));
/* If the alias set for a pointer access is zero all bets are off. */
if (base1_alias_set == -1)
base1_alias_set = get_deref_alias_set (ptrtype1);
if (base1_alias_set == 0)
return true;
if (base2_alias_set == -1)
base2_alias_set = get_deref_alias_set (ptrtype2);
if (base2_alias_set == 0)
if (base1_alias_set == 0
|| base2_alias_set == 0)
return true;
/* If both references are through the same type, they do not alias
@ -1417,7 +1408,8 @@ refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
if (var1_p && ind2_p)
return indirect_ref_may_alias_decl_p (ref2->ref, base2,
offset2, max_size2,
ao_ref_alias_set (ref2), -1,
ao_ref_alias_set (ref2),
ao_ref_base_alias_set (ref2),
ref1->ref, base1,
offset1, max_size1,
ao_ref_alias_set (ref1),
@ -1426,10 +1418,12 @@ refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
else if (ind1_p && ind2_p)
return indirect_refs_may_alias_p (ref1->ref, base1,
offset1, max_size1,
ao_ref_alias_set (ref1), -1,
ao_ref_alias_set (ref1),
ao_ref_base_alias_set (ref1),
ref2->ref, base2,
offset2, max_size2,
ao_ref_alias_set (ref2), -1,
ao_ref_alias_set (ref2),
ao_ref_base_alias_set (ref2),
tbaa_p);
gcc_unreachable ();

11
gcc/tree-ssa-dom.c
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@ -103,7 +103,8 @@ static struct opt_stats_d opt_stats;
static edge optimize_stmt (basic_block, gimple_stmt_iterator,
class const_and_copies *,
class avail_exprs_stack *);
static tree lookup_avail_expr (gimple *, bool, class avail_exprs_stack *);
static tree lookup_avail_expr (gimple *, bool, class avail_exprs_stack *,
bool = true);
static void record_cond (cond_equivalence *, class avail_exprs_stack *);
static void record_equality (tree, tree, class const_and_copies *);
static void record_equivalences_from_phis (basic_block);
@ -1893,7 +1894,8 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
else
new_stmt = gimple_build_assign (rhs, lhs);
gimple_set_vuse (new_stmt, gimple_vuse (stmt));
cached_lhs = lookup_avail_expr (new_stmt, false, avail_exprs_stack);
cached_lhs = lookup_avail_expr (new_stmt, false, avail_exprs_stack,
false);
if (cached_lhs
&& rhs == cached_lhs)
{
@ -1997,7 +1999,7 @@ vuse_eq (ao_ref *, tree vuse1, unsigned int cnt, void *data)
static tree
lookup_avail_expr (gimple *stmt, bool insert,
class avail_exprs_stack *avail_exprs_stack)
class avail_exprs_stack *avail_exprs_stack, bool tbaa_p)
{
expr_hash_elt **slot;
tree lhs;
@ -2054,7 +2056,8 @@ lookup_avail_expr (gimple *stmt, bool insert,
if (!(vuse1 && vuse2
&& gimple_assign_single_p (stmt)
&& TREE_CODE (gimple_assign_lhs (stmt)) == SSA_NAME
&& (ao_ref_init (&ref, gimple_assign_rhs1 (stmt)), true)
&& (ao_ref_init (&ref, gimple_assign_rhs1 (stmt)),
ref.base_alias_set = ref.ref_alias_set = tbaa_p ? -1 : 0, true)
&& walk_non_aliased_vuses (&ref, vuse2,
vuse_eq, NULL, NULL, vuse1) != NULL))
{

2
gcc/tree-ssa-sccvn.c
View File

@ -2249,7 +2249,7 @@ vn_reference_lookup (tree op, tree vuse, vn_lookup_kind kind,
vr1.operands = operands
= valueize_shared_reference_ops_from_ref (op, &valuezied_anything);
vr1.type = TREE_TYPE (op);
vr1.set = get_alias_set (op);
vr1.set = tbaa_p ? get_alias_set (op) : 0;
vr1.hashcode = vn_reference_compute_hash (&vr1);
if ((cst = fully_constant_vn_reference_p (&vr1)))
return cst;