RFR: 8269404: Base64 Encoding optimization enhancements for x86 using AVX-512 [v4]

[Jatin Bhateja]

On Tue, 13 Jul 2021 22:36:23 GMT, Scott Gibbons <github.com+6704669+asgibbons at openjdk.org> wrote:

>> src/hotspot/cpu/x86/stubGenerator_x86_64.cpp line 5463:
>> 
>>> 5461:     if (VM_Version::supports_avx2()
>>> 5462:         && VM_Version::supports_avx512vlbw()) {
>>> 5463:       /*
>> 
>> Its not clear why are you checking for existence of AVX512VLBW if this block is emitting AVX2 code.
>
> There are VL/BW instructions in the loop.

Only ones are evpbroadcastd

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PR: https://git.openjdk.java.net/jdk/pull/4601