[jdk17] RFR: 8269568: JVM crashes when running VectorMask query tests

[Sandhya Viswanathan]

On Thu, 1 Jul 2021 01:30:43 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>>> @DamonFool This is the cleanest solution I could think of.
>>> The problem comes only with newly added intrinsic where firstTrue, lastTrue, trueCount become consumers to VectorStoreMask. All the other consumers of VectorStoreMask consume the right number of bits.
>>> The fix is to make the new intrinsic also consume the right number of bits by doing the 'and' masking.
>> 
>> But we actually do not `and` masking with AVX3.
>> So I'm afraid the root cause is the incorrect code-gen for VectorStoreMask.
>
>> @DamonFool This small patch fixes the problem at hand and at the minimum should go in with JDK 17. You have filed the JDK-8269679 for a more robust fix. Also the masking support is being overhauled as part of JDK 18. Your thoughts?
> 
> Actually, instruct like `storeMask1B` and `storeMask2B` don't need `and masking` for both AVX2 and AVX3.
> But to lower the risk of JDK17, I agree with you.
> Thanks.

Thanks @DamonFool.

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PR: https://git.openjdk.java.net/jdk17/pull/168