[PATCH RFC v2 1/1] x86: default to not accepting Xeon Phi insns

[Jan Beulich]

On 04.08.2025 04:49, Jiang, Haochen wrote:
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: Friday, August 1, 2025 9:34 PM
>>
>> Gcc15 has Xeon Phi support removed. While we don't want to remove
>> support, require these deprecated insns to be enabled explicitly.
>> ---
>> RFC: Likely this wants holding back until gcc15 was actually released,
>>      to avoid negatively affecting in particular gcc14. Question is
>>      whether just the release of gcc15 is enough, or whether we want
>>      people to be able to build/use gcc14 with newer binutils as well,
>>      e.g. until that branch is retired.
>>
> 
> I agree that the time when GCC15 branch retirement is the safest choice.

FTAOD, I meant the gcc14 branch though. Gcc15, with Phi support removed,
doesn't require its default-enabled support in gas.

> While at least for now we did not get complaints about removal in GCC,
> we could also be more aggressive. Timing like one year after GCC15.2
> got released could be ok since most people will use GCC15.2 when
> they start to use GCC15. This will ease rebase effort.

Hmm, this would feel somewhat random / arbitrary to me.

Jan