On Wed, 27 May 2015, Kyrill Tkachov wrote:
> Hi Richard,
>
> On 26/05/15 14:54, Richard Biener wrote:
> > The following fixes the testcase in PR66142
> >
> > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
> >
> > Richard.
> >
> > 2015-05-26 Richard Biener <rguent...@suse.de>
> >
> > PR tree-optimization/66142
> > * tree-ssa-sccvn.c (vn_reference_lookup_3): Manually compare
> > MEM_REFs for the same base address.
> >
> > * gcc.dg/tree-ssa/ssa-fre-44.c: New testcase.
> >
> > Index: gcc/tree-ssa-sccvn.c
> > ===================================================================
> > --- gcc/tree-ssa-sccvn.c (revision 223574)
> > +++ gcc/tree-ssa-sccvn.c (working copy)
> > @@ -1894,7 +1894,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree
> > size2 = lhs_ref.size;
> > maxsize2 = lhs_ref.max_size;
> > if (maxsize2 == -1
> > - || (base != base2 && !operand_equal_p (base, base2, 0))
> > + || (base != base2
> > + && (TREE_CODE (base) != MEM_REF
> > + || TREE_CODE (base2) != MEM_REF
> > + || TREE_OPERAND (base, 0) != TREE_OPERAND (base2, 0)
> > + || !tree_int_cst_equal (TREE_OPERAND (base, 1),
> > + TREE_OPERAND (base2, 1))))
> > || offset2 > offset
> > || offset2 + size2 < offset + maxsize)
> > return (void *)-1;
> > Index: gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c
> > ===================================================================
> > --- gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c (revision 0)
> > +++ gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c (working copy)
> > @@ -0,0 +1,62 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O -fdump-tree-fre1" } */
> > +
> > +struct A { float x, y; };
> > +struct B { struct A u; };
> > +void bar (struct A *);
> > +
> > +float
> > +f1 (struct B *x, int y)
> > +{
> > + struct A p;
> > + p.x = 1.0f;
> > + p.y = 2.0f;
> > + struct A *q = &x[y].u;
> > + *q = p;
> > + float f = x[y].u.x + x[y].u.y;
> > + bar (&p);
> > + return f;
> > +}
> > +
> > +float
> > +f2 (struct B *x, int y)
> > +{
> > + struct A p;
> > + p.x = 1.0f;
> > + p.y = 2.0f;
> > + x[y].u = p;
> > + float f = x[y].u.x + x[y].u.y;
> > + bar (&p);
> > + return f;
> > +}
> > +
> > +float
> > +f3 (struct B *x, int y)
> > +{
> > + struct A p;
> > + p.x = 1.0f;
> > + p.y = 2.0f;
> > + struct A *q = &x[y].u;
> > + __builtin_memcpy (&q->x, &p.x, sizeof (float));
> > + __builtin_memcpy (&q->y, &p.y, sizeof (float));
> > + *q = p;
> > + float f = x[y].u.x + x[y].u.y;
> > + bar (&p);
> > + return f;
> > +}
> > +
> > +float
> > +f4 (struct B *x, int y)
> > +{
> > + struct A p;
> > + p.x = 1.0f;
> > + p.y = 2.0f;
> > + __builtin_memcpy (&x[y].u.x, &p.x, sizeof (float));
> > + __builtin_memcpy (&x[y].u.y, &p.y, sizeof (float));
> > + float f = x[y].u.x + x[y].u.y;
> > + bar (&p);
> > + return f;
> > +}
>
> I see this test failing on arm-none-eabi. In particular, the f4 dump is the
> only one
> that doesn't contain "return 3.0". Instead it is:
> f4 (struct B * x, int y)
> {
> float f;
> struct A p;
> unsigned int y.3_5;
> unsigned int _6;
> struct B * _8;
> float * _9;
> float * _14;
> float _19;
> float _23;
>
> <bb 2>:
> p.x = 1.0e+0;
> p.y = 2.0e+0;
> y.3_5 = (unsigned int) y_4(D);
> _6 = y.3_5 * 8;
> _8 = x_7(D) + _6;
> _9 = &_8->u.x;
> __builtin_memcpy (_9, &p.x, 4);
> _14 = &_8->u.y;
> __builtin_memcpy (_14, &p.y, 4);
> _19 = _8->u.x;
> _23 = _8->u.y;
> f_24 = _19 + _23;
> bar (&p);
> p ={v} {CLOBBER};
> return f_24;
>
> }
>
> Thanks,
> Kyrill
Thanks - the following patch fixes this (tested with a cross). It
also removes a spurious aggregate assignment from f3 which makes
it fail without the patch as well (as expected).
Bootstrap / regtest in progress on x86_64-unknown-linux-gnu.
Richard.
2015-05-28 Richard Biener <rguent...@suse.de>
PR tree-optimization/66142
* tree-ssa-sccvn.c (vn_reference_lookup_3): Handle non-GIMPLE
values better in memcpy destination handling. Handle non-aliasing
we discover here.
* gcc.dg/tree-ssa/ssa-fre-44.c: Fixup.
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c (revision 223802)
--- gcc/tree-ssa-sccvn.c (working copy)
*************** vn_reference_lookup_3 (ao_ref *ref, tree
*** 2028,2034 ****
lhs = gimple_call_arg (def_stmt, 0);
lhs_offset = 0;
if (TREE_CODE (lhs) == SSA_NAME)
! lhs = SSA_VAL (lhs);
if (TREE_CODE (lhs) == ADDR_EXPR)
{
tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (lhs, 0),
--- 2028,2043 ----
lhs = gimple_call_arg (def_stmt, 0);
lhs_offset = 0;
if (TREE_CODE (lhs) == SSA_NAME)
! {
! lhs = SSA_VAL (lhs);
! if (TREE_CODE (lhs) == SSA_NAME)
! {
! gimple def_stmt = SSA_NAME_DEF_STMT (lhs);
! if (gimple_assign_single_p (def_stmt)
! && gimple_assign_rhs_code (def_stmt) == ADDR_EXPR)
! lhs = gimple_assign_rhs1 (def_stmt);
! }
! }
if (TREE_CODE (lhs) == ADDR_EXPR)
{
tree tem = get_addr_base_and_unit_offset (TREE_OPERAND (lhs, 0),
*************** vn_reference_lookup_3 (ao_ref *ref, tree
*** 2039,2044 ****
--- 2048,2055 ----
&& tree_fits_uhwi_p (TREE_OPERAND (tem, 1)))
{
lhs = TREE_OPERAND (tem, 0);
+ if (TREE_CODE (lhs) == SSA_NAME)
+ lhs = SSA_VAL (lhs);
lhs_offset += tree_to_uhwi (TREE_OPERAND (tem, 1));
}
else if (DECL_P (tem))
*************** vn_reference_lookup_3 (ao_ref *ref, tree
*** 2089,2098 ****
|| TREE_OPERAND (lhs, 0) != base)))
return (void *)-1;
- /* And the access has to be contained within the memcpy destination. */
at = offset / BITS_PER_UNIT;
if (TREE_CODE (base) == MEM_REF)
at += tree_to_uhwi (TREE_OPERAND (base, 1));
if (lhs_offset > at
|| lhs_offset + copy_size < at + maxsize / BITS_PER_UNIT)
return (void *)-1;
--- 2100,2114 ----
|| TREE_OPERAND (lhs, 0) != base)))
return (void *)-1;
at = offset / BITS_PER_UNIT;
if (TREE_CODE (base) == MEM_REF)
at += tree_to_uhwi (TREE_OPERAND (base, 1));
+ /* If the access is completely outside of the memcpy destination
+ area there is no aliasing. */
+ if (lhs_offset >= at + maxsize / BITS_PER_UNIT
+ || lhs_offset + copy_size <= at)
+ return NULL;
+ /* And the access has to be contained within the memcpy destination. */
if (lhs_offset > at
|| lhs_offset + copy_size < at + maxsize / BITS_PER_UNIT)
return (void *)-1;
Index: gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c (revision 223802)
--- gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-44.c (working copy)
*************** f3 (struct B *x, int y)
*** 39,45 ****
struct A *q = &x[y].u;
__builtin_memcpy (&q->x, &p.x, sizeof (float));
__builtin_memcpy (&q->y, &p.y, sizeof (float));
- *q = p;
float f = x[y].u.x + x[y].u.y;
bar (&p);
return f;
--- 39,44 ----
