[RS6000] Fix PR66033, nop pattern

[David Edelsohn]

On Wed, May 6, 2015 at 8:22 AM, Alan Modra <amodra@gmail.com> wrote:
> Using a plain [(const_int 0)] for a nop pattern apparently no longer
> survives optimization.  rtl_dce deletes these nops.  This patch uses
> an unspec so that explicitly inserted nops are kept.
> Fixing that revealed a number of patterns and splitters that
> accidentally inserted [(const_int 0)] insns into rtl.
>
> Bootstrapped and regression tested powerpc64-linux and
> powerpc64le-linux.  OK for mainline?
>
>         PR target/66033
>         * config/rs6000/rs6000.md (nop): Use an unspec pattern.
>         (UNSPEC_NOP): Define.
>         (reload_vsx_from_gpr<mode>): Add missing DONE.
>         (reload_gpr_from_vsx<mode>): Likewise.
>         * config/rs6000/vsx.md (vsx_mul_v2di): Likewise.
>         (vsx_div_v2di, vsx_udiv_v2di): Likewise.

Okay.

Thanks, David