On Thu, 2014-01-23 at 19:42 -0500, David Edelsohn wrote:
> On Thu, Jan 23, 2014 at 6:43 PM, Bill Schmidt
> <wschm...@linux.vnet.ibm.com> wrote:
> > Hi,
> >
> > While testing another patch, I hit a regression at -O2 for two of the
> > vector shuffle tests. This patch fixes the problem.
> >
> > The problem was introduced with the little endian fixes for
> > VEC_PERM_EXPR. The original change performed the necessary
> > transformation at expand time, but this is incorrect. This creates a
> > technically incorrect representation in the RTL, and RTL simplification
> > can subsequently fold the expression in an unexpected way. The correct
> > fix is to delay the transformation until final code generation.
> >
> > Bootstrapped and tested on powerpc64{,le}-unknown-linux-gnu with no
> > regressions. Is this ok for trunk? I will also plan to backport this
> > to ibm/gcc-4_8-branch after burn-in.
> >
> > Thanks,
> > Bill
> >
> >
> > 2014-01-23 Bill Schmidt <wschm...@linux.vnet.ibm.com>
> >
> > * config/rs6000/rs6000.c (rs6000_expand_vec_perm_const_1): Remove
> > correction for little endian...
> > * config/rs6000/vsx.md (vsx_xxpermdi2_<mode>_1): ...and move it to
> > here.
>
> Okay. Would you please move the comment also?
Oh, sure. Will do.
Bill
>
> Thanks, David
>
