[PATCH v2] x86: Add %ME for instructions do not need {evex} prefix with memory

[Jiang, Haochen]

> From: Jan Beulich <jbeulich@suse.com>
> Sent: Tuesday, December 3, 2024 4:40 PM
> 
> On 03.12.2024 08:59, Haochen Jiang wrote:
> > @@ -14,7 +14,7 @@
> >      { "vprol%DQ",	{ Vex, EXx, Ib }, PREFIX_DATA },
> >      { VEX_W_TABLE (EVEX_W_0F72_R_2) },
> >      { Bad_Opcode },
> > -    { "%XEvpsra%DQ",	{ Vex, EXx, Ib }, PREFIX_DATA },
> > +    { "%MEvpsra%DQ",	{ Vex, EXx, Ib }, PREFIX_DATA },
> >      { Bad_Opcode },
> >      { VEX_W_TABLE (EVEX_W_0F72_R_6) },
> >    },
> 
> If already we're aiming at reducing unnecessary {evex} prefixes, I think we
> should go a step further and also deal with VPSRAQ being EVEX-only. I.e.
> VPSRAD wants to have %ME, but VPSRAQ wants to have no such prefix at all.

You are right here. I did not realize no VEX part for VPSRAQ.

We should eliminate them.

Thx,
Haochen