On Fri, 17 May 2013, Jakub Jelinek wrote:
> On Thu, May 16, 2013 at 07:59:00PM +0200, Mikael Pettersson wrote:
> > Jakub Jelinek writes:
> > > On Thu, Apr 25, 2013 at 11:47:02PM +0200, Jakub Jelinek wrote:
> > > > This patch adds folding of constant arguments v>> and v<<, which helps
> > to
> > > > optimize the testcase from the PR back into constant store after
> > vectorized
> > > > loop is unrolled.
> > >
> > > As this fixes a regression on the 4.8 branch, I've backported it (and
> > > minimal prerequisite for that) to 4.8 branch too.
> >
> > Unfortunately this patch makes gcc.dg/vect/no-scevccp-outer-{7,13}.c fail
> > on powerpc64-linux:
> >
> > +FAIL: gcc.dg/vect/no-scevccp-outer-13.c execution test
> > +FAIL: gcc.dg/vect/no-scevccp-outer-7.c execution test
> >
> > which is a regression from 4.8-20130502. Reverting r198580 fixes it.
> >
> > The same FAILs also occur on trunk.
>
> Ah right, I was confused by the fact that VEC_RSHIFT_EXPR is used
> not just on little endian targets, but on big endian as well
> (VEC_LSHIFT_EXPR is never emitted), but the important spot is
> when extracting the scalar result from the vector:
>
> if (BYTES_BIG_ENDIAN)
> bitpos = size_binop (MULT_EXPR,
> bitsize_int (TYPE_VECTOR_SUBPARTS (vectype) - 1),
> TYPE_SIZE (scalar_type));
> else
> bitpos = bitsize_zero_node;
>
> Fixed thusly, ok for trunk/4.8?
Ok with a comment in front of (code == VEC_RSHIFT_EXPR) ^
(!BYTES_BIG_ENDIAN)
Thanks,
Richard.
> 2013-05-17 Jakub Jelinek <[email protected]>
>
> PR tree-optimization/57051
> * fold-const.c (const_binop) <case VEC_LSHIFT_EXPR,
> case VEC_RSHIFT_EXPR>: Fix BYTES_BIG_ENDIAN handling.
>
> --- gcc/fold-const.c.jj 2013-05-16 12:36:28.000000000 +0200
> +++ gcc/fold-const.c 2013-05-17 08:38:12.575117676 +0200
> @@ -1393,7 +1393,7 @@ const_binop (enum tree_code code, tree a
> if (shiftc >= outerc || (shiftc % innerc) != 0)
> return NULL_TREE;
> int offset = shiftc / innerc;
> - if (code == VEC_LSHIFT_EXPR)
> + if ((code == VEC_RSHIFT_EXPR) ^ (!BYTES_BIG_ENDIAN))
> offset = -offset;
> tree zero = build_zero_cst (TREE_TYPE (type));
> for (i = 0; i < count; i++)
>
>
> Jakub
>
>
--
Richard Biener <[email protected]>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend
