RFR: 8291600: [vectorapi] vector cast op check is not always needed for vector mask cast [v7]

[Xiaohong Gong]

On Thu, 15 Sep 2022 06:28:01 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Xiaohong Gong has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:
>> 
>>  - Merge branch 'jdk:master' into JDK-8291600
>>  - Address review comments
>>  - Add vector cast op check for vector mask for some cases
>>  - Revert the unify changes to vector mask cast
>>  - Merge branch 'jdk:master' into JDK-8291600
>>  - Fix x86 codegen issue
>>  - Unify VectorMaskCast for all platforms
>>  - Merge branch 'master' into JDK-8291600
>>  - 8291600: [vectorapi] vector cast op check is not always needed for vector mask cast
>
> src/hotspot/share/opto/vectorIntrinsics.cpp line 2486:
> 
>> 2484:       ((src_type->isa_vectmask() == NULL && dst_type->isa_vectmask()) ||
>> 2485:        (dst_type->isa_vectmask() == NULL && src_type->isa_vectmask()) ||
>> 2486:        num_elem_from != num_elem_to)) {
> 
> This check is already done on [java side](https://github.com/openjdk/jdk/blob/master/src/jdk.incubator.vector/share/classes/jdk/incubator/vector/Double512Vector.java#L643).

Yes, it is. Just want to double check in the compiler side, or it maybe confusing if someone is not familiar with the vector api java codes.

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PR: https://git.openjdk.org/jdk/pull/9737