[PATCH RFC v2 0/1] x86: don't enable deprecated ISA extensions by default

[Jiang, Haochen]

> From: Jan Beulich <jbeulich@suse.com>
> Sent: Friday, August 1, 2025 9:32 PM
> 
> Beyond that there are further discontinued extensions, which however gcc
> still supports: HLE, VP2INTERSECT, and KeyLocker on the Intel side, TBM,
> XOP, FMA4, and LWP for AMD. Question is what (if anything) to do there,
> which may depend on what gcc's plans are.
> 
> Main question to be answered is when an appropriate time is to make such
> adjustments (here as well as for the above items, if and when support
> for them gets removed from gcc).
> 

Xeon Phi removal is based on all products EOL and the most important thing is 
that we have motivation to do that in GCC due to AVX10 introduction. They are
causing some issues in corner cases need to be work around in GCC.

For the other ISAs, let's see if anyone has motivation to do that, while for newly
discontinued KeyLocker, it still has a long long long way to go since we need to
at least wait for all products with Key Locker EOL.

Thx,
Haochen