RFR: 8328998: Encoding support for Intel APX extended general-purpose registers [v22]

[Vladimir Kozlov]

On Fri, 17 May 2024 17:48:25 GMT, Steve Dohrmann <duke at openjdk.org> wrote:

>> src/hotspot/cpu/x86/vm_version_x86.cpp line 1005:
>> 
>>> 1003:   }
>>> 1004: 
>>> 1005:   if (UseAPX && (UseAVX < 3)) {
>> 
>> A comment here will be helpful stating the need to disable APX functionality for non AVX512 targets, please note UseAVX is set to level 3 based on existence of CPUID (EAX=07, EBX[16] = AVX512F) bit, and future AVX10 targets may support APX.
>
> Thanks.  I added a comment.

Is it enough to have AVX512F present for APX? What about Knight CPUs which have limited AVX512 features?

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PR Review Comment: https://git.openjdk.org/jdk/pull/18476#discussion_r1608674283