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Re: [PATCH] x86: fix handling of 64-bit operand size VPCMPESTR{I,M}
- From: "Jan Beulich" <JBeulich at suse dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: "Binutils" <binutils at sourceware dot org>
- Date: Thu, 23 Feb 2017 02:11:40 -0700
- Subject: Re: [PATCH] x86: fix handling of 64-bit operand size VPCMPESTR{I,M}
- Authentication-results: sourceware.org; auth=none
- References: <58AC2745020000780013C32F@prv-mh.provo.novell.com> <CAMe9rOr7r+zQCgoF0zMSjGtG+J76Fq=3gMxBKif46S1z-HF=uw@mail.gmail.com>
>>> On 22.02.17 at 19:52, <hjl.tools@gmail.com> wrote:
> On Tue, Feb 21, 2017 at 2:40 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}. For that to work,
>> 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.
>
> I prefer to use the "q" suffix instead of using rex64 prefix. It will work with
> both VPCMPESTR{I,M} and PCMPESTR{I,M}.
Hmm, I'll see about doing that, but explicit REX prefixes should be
honored anyway imo. Furthermore using a suffix would add one
more example of bending Intel syntax, which doesn't know of any
suffixes for the vast majority of instructions (including the ones
here).
Jan