[vectorIntrinsics+mask] RFR: 8264563: Add masked vector intrinsics for binary/store operations [v5]

[Jatin Bhateja]

On Tue, 13 Apr 2021 08:00:23 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> Hi, this is the basic masking support PR for Vector API mask operations on platforms like SVE/AVX-512. The main codes are from [1], which contains:
>> 
>> - The predicate register allocation for Arm SVE, and vector mask type definition.
>> - The basic optimization for parts of the mask operations with masking feature. It contains:   
>>  
>>   1. Vector API java implementation changes for masked binary/store.
>>   2. C2 compiler mid-end changes, including new vector intrinsics implementation and mask IRs.
>> 
>> Note that for easier discussion, this PR only provides the changes for limited masked operations (e.g. binary/store) and the mask generations (e.g. load/compare/maskAll). We will continue working on the following missing parts:
>> 
>> - Mask support for other operations (unary,ternary,reduction,load,etc.)
>> - More mask IRs implementation (and/or/xor, toVector, allTrue, anyTrue, trueCount, eq, etc)
>> - Vector boxing/unboxing support for mask type (deoptimization support for predicate registers)
>> 
>> Also note that this PR doesn't contain any backend implementations. So the blend pattern will be generated as before. Regarding to the AArch64 SVE backend support, we will create a separate PR based on this one in future.
>>   
>> [1] https://github.com/openjdk/panama-vector/pull/40
>> 
>> See more details from:
>> http://cr.openjdk.java.net/~xgong/rfr/mask/Vector%20API%20masking%20support%20proposal%20for%20Arm%20SVE.pdf
>> http://cr.openjdk.java.net/~xgong/rfr/mask/VectorAPI%20masking%20support.pdf
>> 
>> Any suggestions and discussions are welcome! Thanks a lot!
>
> Xiaohong Gong has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove null checking for the mask argument in API implementation

Would prefer suggested  cleanup to be done along with this patch instead of pending it to next one.
Rest of the changes looks ok.

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Marked as reviewed by jbhateja (Committer).

PR: https://git.openjdk.java.net/panama-vector/pull/57