RFR: 8290322: Optimize Vector.rearrange over byte vectors for AVX512BW targets. [v4]

[Jatin Bhateja]

On Fri, 19 Aug 2022 23:53:46 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8290322: Review comments resolution.
>
> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 5710:
> 
>> 5708:   vpsllq(xtmp2, xtmp1, 0x1, vlen_enc);
>> 5709:   evpcmpb(ktmp2, k0, shuffle, xtmp2, Assembler::lt, true, vlen_enc);
>> 5710:   kandql(ktmp2, ktmp1, ktmp2);
> 
> This sequence could be replaced by:
> evpcmpb(ktmp2, ktmp1, shuffle, xtmp2, Assembler::lt, true, vlen_enc);
> 
> It could also be further improved to:
> evpcmpb(ktmp1, ktmp1, shuffle, xtmp2, Assembler::lt, true, vlen_enc);
> 
> Thereby removing the need for ktmp2 altogether.
> 
> There are three instances of this in the algorithm.
> 
> Rest of the changes look good to me.

Thanks @sviswa7 for your comments.

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PR: https://git.openjdk.org/jdk/pull/9498