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re PR middle-end/41317 (folding causes strict aliasing violation)

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2009-09-09  Richard Guenther  <rguenther@suse.de>

	PR middle-end/41317
	* tree-ssa-ccp.c (maybe_fold_offset_to_component_ref): Remove
	code dealing with plain pointer bases.
	(maybe_fold_offset_to_reference): Likewise.
	(maybe_fold_stmt_addition): Adjust.

	* gcc.c-torture/execute/pr41317.c: New testcase.
	* gcc.dg/tree-ssa/forwprop-11.c: XFAIL.
	* gcc.dg/tree-ssa/forwprop-12.c: Likewise.

From-SVN: r151559
This commit is contained in:
Richard Guenther 2009-09-09 14:35:51 +00:00 • committed by Richard Biener
parent ccffb7554e
commit 5a4b005fef
6 changed files with 82 additions and 69 deletions
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8
gcc/ChangeLog
View file

@ -1,3 +1,11 @@
2009-09-09 Richard Guenther <rguenther@suse.de>
PR middle-end/41317
* tree-ssa-ccp.c (maybe_fold_offset_to_component_ref): Remove
code dealing with plain pointer bases.
(maybe_fold_offset_to_reference): Likewise.
(maybe_fold_stmt_addition): Adjust.
2009-09-09 Richard Guenther <rguenther@suse.de>
* tree.c (free_lang_data_in_type): Do not free the type variant

7
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,10 @@
2009-09-09 Richard Guenther <rguenther@suse.de>
PR middle-end/41317
* gcc.c-torture/execute/pr41317.c: New testcase.
* gcc.dg/tree-ssa/forwprop-11.c: XFAIL.
* gcc.dg/tree-ssa/forwprop-12.c: Likewise.
2009-09-08 Dodji Seketeli <dodji@redhat.com>
Fix some test breakages on Darwin

28
gcc/testsuite/gcc.c-torture/execute/pr41317.c Normal file
View file

@ -0,0 +1,28 @@
extern void abort (void);
struct A
{
int i;
};
struct B
{
struct A a;
int j;
};
static void
foo (struct B *p)
{
((struct A *)p)->i = 1;
}
int main()
{
struct A a;
a.i = 0;
foo ((struct B *)&a);
if (a.i != 1)
abort ();
return 0;
}

2
gcc/testsuite/gcc.dg/tree-ssa/forwprop-11.c
View file

@ -15,5 +15,5 @@ int g(int *p, int n)
return q[-1];
}
/* { dg-final { scan-tree-dump-times "= \\\(\\\*a_..\\\)\\\[1\\\];" 2 "forwprop1" } } */
/* { dg-final { scan-tree-dump-times "= \\\(\\\*a_..\\\)\\\[1\\\];" 2 "forwprop1" { xfail *-*-* } } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

2
gcc/testsuite/gcc.dg/tree-ssa/forwprop-12.c
View file

@ -18,5 +18,5 @@ int bar(struct X *p, int i)
/* We should have propagated the base array address through the
address arithmetic into the memory access as an array access. */
/* { dg-final { scan-tree-dump-times "->a\\\[D\\\." 2 "forwprop1" } } */
/* { dg-final { scan-tree-dump-times "->a\\\[D\\\." 2 "forwprop1" { xfail *-*-* } } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

104
gcc/tree-ssa-ccp.c
View file

@ -1818,8 +1818,7 @@ maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset,
static tree
maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
tree base, tree offset,
tree orig_type, bool base_is_ptr)
tree base, tree offset, tree orig_type)
{
tree f, t, field_type, tail_array_field, field_offset;
tree ret;
@ -1871,8 +1870,6 @@ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
if (cmp == 0
&& useless_type_conversion_p (orig_type, field_type))
{
if (base_is_ptr)
base = build1 (INDIRECT_REF, record_type, base);
t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
return t;
}
@ -1897,13 +1894,8 @@ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
/* If we matched, then set offset to the displacement into
this field. */
if (base_is_ptr)
new_base = build1 (INDIRECT_REF, record_type, base);
else
new_base = base;
protected_set_expr_location (new_base, loc);
new_base = build3 (COMPONENT_REF, field_type, new_base, f, NULL_TREE);
protected_set_expr_location (new_base, loc);
new_base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
SET_EXPR_LOCATION (new_base, loc);
/* Recurse to possibly find the match. */
ret = maybe_fold_offset_to_array_ref (loc, new_base, t, orig_type,
@ -1911,7 +1903,7 @@ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
if (ret)
return ret;
ret = maybe_fold_offset_to_component_ref (loc, field_type, new_base, t,
orig_type, false);
orig_type);
if (ret)
return ret;
}
@ -1925,11 +1917,6 @@ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
/* If we get here, we've got an aggregate field, and a possibly
nonzero offset into them. Recurse and hope for a valid match. */
if (base_is_ptr)
{
base = build1 (INDIRECT_REF, record_type, base);
SET_EXPR_LOCATION (base, loc);
}
base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
SET_EXPR_LOCATION (base, loc);
@ -1938,7 +1925,7 @@ maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
if (t)
return t;
return maybe_fold_offset_to_component_ref (loc, field_type, base, offset,
orig_type, false);
orig_type);
}
/* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
@ -1955,61 +1942,44 @@ maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
{
tree ret;
tree type;
bool base_is_ptr = true;
STRIP_NOPS (base);
if (TREE_CODE (base) == ADDR_EXPR)
if (TREE_CODE (base) != ADDR_EXPR)
return NULL_TREE;
base = TREE_OPERAND (base, 0);
/* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
so it needs to be removed and new COMPONENT_REF constructed.
The wrong COMPONENT_REF are often constructed by folding the
(type *)&object within the expression (type *)&object+offset */
if (handled_component_p (base))
{
base_is_ptr = false;
base = TREE_OPERAND (base, 0);
/* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
so it needs to be removed and new COMPONENT_REF constructed.
The wrong COMPONENT_REF are often constructed by folding the
(type *)&object within the expression (type *)&object+offset */
if (handled_component_p (base))
HOST_WIDE_INT sub_offset, size, maxsize;
tree newbase;
newbase = get_ref_base_and_extent (base, &sub_offset,
&size, &maxsize);
gcc_assert (newbase);
if (size == maxsize
&& size != -1
&& !(sub_offset & (BITS_PER_UNIT - 1)))
{
HOST_WIDE_INT sub_offset, size, maxsize;
tree newbase;
newbase = get_ref_base_and_extent (base, &sub_offset,
&size, &maxsize);
gcc_assert (newbase);
if (size == maxsize
&& size != -1
&& !(sub_offset & (BITS_PER_UNIT - 1)))
{
base = newbase;
if (sub_offset)
offset = int_const_binop (PLUS_EXPR, offset,
build_int_cst (TREE_TYPE (offset),
sub_offset / BITS_PER_UNIT), 1);
}
base = newbase;
if (sub_offset)
offset = int_const_binop (PLUS_EXPR, offset,
build_int_cst (TREE_TYPE (offset),
sub_offset / BITS_PER_UNIT), 1);
}
if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
&& integer_zerop (offset))
return base;
type = TREE_TYPE (base);
}
else
{
base_is_ptr = true;
if (!POINTER_TYPE_P (TREE_TYPE (base)))
return NULL_TREE;
type = TREE_TYPE (TREE_TYPE (base));
}
ret = maybe_fold_offset_to_component_ref (loc, type, base, offset,
orig_type, base_is_ptr);
if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
&& integer_zerop (offset))
return base;
type = TREE_TYPE (base);
ret = maybe_fold_offset_to_component_ref (loc, type, base, offset, orig_type);
if (!ret)
{
if (base_is_ptr)
{
base = build1 (INDIRECT_REF, type, base);
SET_EXPR_LOCATION (base, loc);
}
ret = maybe_fold_offset_to_array_ref (loc,
base, offset, orig_type, true);
}
ret = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type, true);
return ret;
}
@ -2286,7 +2256,7 @@ maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
t = maybe_fold_offset_to_array_ref (loc, op0, op1, ptd_type, true);
if (!t)
t = maybe_fold_offset_to_component_ref (loc, TREE_TYPE (op0), op0, op1,
ptd_type, false);
ptd_type);
if (t)
{
t = build1 (ADDR_EXPR, res_type, t);