[PATCH] x86: Set Prefer_No_VZEROUPPER if AVX512ER is available

[Florian Weimer]

On 04/17/2017 10:13 PM, H.J. Lu wrote:
> On Mon, Apr 17, 2017 at 1:06 PM, Florian Weimer <fweimer@redhat.com> wrote:
>> On 04/17/2017 09:54 PM, H.J. Lu wrote:
>>>
>>> Since AVX512ER is unique to Xeon Phi, set Prefer_No_VZEROUPPER if
>>> AVX512ER is available.
>>
>>
>> This approach doesn't seem very future-proof to me.
>>
> 
> AVX512ER won't be implemented in any Xeon processors and it will be in
> all Xeon Phi processors.   In this way, we don't need to check CPU model
> numbers when setting Prefer_No_VZEROUPPER.   It will work with current
> and future Xeon Phi and non-Xeon Phi processors.

Well, okay.  I see it's in the Intel-specific block, so the change 
should be okay.

Thanks,
Florian