On Thu, 12 May 2022 22:48:26 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:
>> Jatin Bhateja has updated the pull request incrementally with one additional
>> commit since the last revision:
>>
>> 8284960: Review comments resolution.
>
> src/hotspot/cpu/x86/stubGenerator_x86_64.cpp line 7953:
>
>> 7951: StubRoutines::x86::_vector_iota_indices =
>> generate_iota_indices("iota_indices");
>> 7952:
>> 7953: if (UsePopCountInstruction && VM_Version::supports_avx2() &&
>> !VM_Version::supports_avx512_vpopcntdq()) {
>
> Why is the LUT unconditionally generated? `UsePopCountInstruction` still
> guides the usages.
LUT should be generated only if UsePopCountInsturction is false and iff target
does not support necessary features, AVX512POPCNTDQ (for int/long vectors) and
AVX512_BITALG (for sub-word vectors). Please refer to following discussion
where it was suggested to restrict the scope of flag to only scalar popcount
operation.
https://github.com/openjdk/panama-vector/pull/185#discussion_r847758463
-------------
PR: https://git.openjdk.java.net/jdk/pull/8425
