RFR: 8329031: CPUID feature detection for Advanced Performance Extensions (Intel® APX) [v2]

[Vladimir Kozlov]

On Fri, 7 Jun 2024 02:12:31 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> src/hotspot/cpu/x86/vm_version_x86.cpp line 1052:
>> 
>>> 1050: 
>>> 1051:   // Currently APX support is only enabled for targets supporting AVX512VL feature.
>>> 1052:   if (UseAPX && (!supports_apx_f() || !supports_avx512vl())) {
>> 
>> This code should be after UseAVX checks.
>
> Its purposefully placed after modifications to CPU_* features flags if user explicitly sets UseAVX < 3.

Got it. I missed that we have separate UseAVX checks for <3 and < 2 and < 1.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18562#discussion_r1630542872