RFR: 8322768: Optimize non-subword vector compress and expand APIs for AVX2 target. [v2]

[Jatin Bhateja]

On Thu, 4 Jan 2024 13:41:40 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Updating copyright year of modified files.
>
> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 5307:
> 
>> 5305:     assert(bt == T_LONG || bt == T_DOUBLE, "");
>> 5306:     vmovmskpd(rtmp, mask, vec_enc);
>> 5307:     shlq(rtmp, 5);
> 
> Might this need to be 6? If I understand right, then you want to have a 64bit stride, hence 2^6, right?
> If that is correct, then this did not show in your tests, and you need a regression test anyway.

This computes the byte offset from start of the table, both integer and long permute table have same row sizes, 8 int elements vs 4 long elements.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17261#discussion_r1442555037