[PATCH, rs6000] More efficient vector permute for little endian

[David Edelsohn]

On Thu, Mar 20, 2014 at 9:38 PM, Bill Schmidt
<wschmidt@linux.vnet.ibm.com> wrote:
> Hi,
>
> The original workaround for vector permute on a little endian platform
> includes subtracting each element of the permute control vector from 31.
> Because the upper 3 bits of each element are unimportant, this was
> implemented as subtracting the whole vector from a splat of -1.  On
> reflection this can be done more efficiently with a vector nor
> operation.  This patch makes that change.
>
> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no
> regressions.  Is this ok for trunk?
>
> Thanks,
> Bill
>
>
> 2014-03-20  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
>
>         * config/rs6000/rs6000.c (rs6000_expand_vector_set): Generate a
>         pattern for vector nor instead of subtract from splat(-1).
>         (altivec_expand_vec_perm_const_le): Likewise.

Okay.

Thanks, David