[PATCH v2] x86: fix handling of 64-bit operand size VPCMPESTR{I,M}

[H.J. Lu]

On Thu, Feb 23, 2017 at 4:40 AM, Jan Beulich <JBeulich@suse.com> wrote:
> Just like REX.W affects operand size of the implicit rAX/rDX inputs to
> PCMPESTR{I,M}, VEX.W does for VPCMPESTR{I,M}. Allow Q or L suffixes on
> the instructions for AT&T mode.
>
> For Intel mode, however, suffixes aren't the preferred choice, so
> build_vex_prefix() needs to not only honor internally specified REX
> flags (converting them to their VEX equivalents), but also such
> resulting from explicit REX* prefix uses. Also adjust
> build_evex_prefix() for consistency.

Please don't use EXISTING REX prefixes for this purpose.  A new
prefix to control encoding is better, but it probably belongs to another
patch.


-- 
H.J.