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

[Jatin Bhateja]

On Thu, 4 Jan 2024 13:33:08 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.
>
> test/micro/org/openjdk/bench/jdk/incubator/vector/ColumnFilterBenchmark.java line 76:
> 
>> 74:         longinCol = new long[size];
>> 75:         longoutCol = new long[size];
>> 76:         lpivot = size / 2;
> 
> I'd be interested to see what happens if you move up or down the "density" of elements that you accept. Would the simple branch prediction be faster if the density is low enough, i.e. we almost take no element.
> 
> Though maybe that is not compiler problem but a user-problem?

Included fuzzy filter micro with varying mask density.
![image](https://github.com/openjdk/jdk/assets/59989778/a6af21cc-36c0-4503-aeb3-e66b862da2e1)

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PR Review Comment: https://git.openjdk.org/jdk/pull/17261#discussion_r1442557565