[vectorIntrinsics] RFR: 8274569: X86 backend related incorrectness issues in legacy store mask patterns [v2]

[Sandhya Viswanathan]

On Mon, 4 Oct 2021 06:37:47 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> - Issue was seen while unit testing changes for masking related optimizations on vectorIntrinsics branch.
>> 
>> - Following patterns result into incorrect store mask computation, even though contextually store-mask is followed by StoreVector which does takes care of various vector sizes. But C2 does emit VectorStoreMask in IR to populate a byte vector. 
>> 
>>   - instruct storeMask2B
>>   - instruct storeMask4B
>>   - instruct storeMask8B
>>   - instruct storeMask8B_avx
>> 
>> - Replicate with immI operand is correctly taking care of shorter vector lengths thus it can be fall back case for following pattern with immediate -1 argument. 
>>   - instruct ReplI_M1
>>   
>> Patch also adds a test case which exhaustively coves load/store vector masks operations for different SPECIES.
>
> Jatin Bhateja has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - 8274569: Fixes for maskquery operations over partial vectors (less than 16 bytes).
>  - Merge branch 'vectorIntrinsics' of http://github.com/openjdk/panama-vector into JDK-8274569
>  - 8274569: X86 backend related incorrectness issues in legacy storemask patterns

Looks good to me.

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Marked as reviewed by sviswanathan (Committer).

PR: https://git.openjdk.java.net/panama-vector/pull/139