[vectorIntrinsics+mask] RFR: 8266287: Basic mask IR implementation for the Vector API masking feature support [v5]

[Sandhya Viswanathan]

On Thu, 1 Jul 2021 05:51:38 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> Based on [1], this patch adds the C2 compiler mid-end changes for the masking feature support. It mainly contains:
>>  1) Generation of the mask IRs for vector mask, including:
>>     - Mask generations, e.g. load/compare/maskAll
>>     - Mask operations, e.g. and/or/xor
>>  2) Conversions between vector and mask after loading mask values from memory and before storing mask values into memory
>>  3) Generation of the vector IRs which need the mask value as the control
>>     - The mask value is appended to the original vector node's input list
>> 
>> With this change, the bottom type of the vector mask will be set to `"TypeVectMask"` if the platform supports the masking feature and the backend implementations are added.
>> 
>> Note that this patch only contains the compiler mid-end changes. The backend implementations for SVE/AVX-512 will be in the
>> followed-up patches.
>> 
>> [1] https://github.com/openjdk/panama-vector/pull/57
>
> Xiaohong Gong has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains seven commits:
> 
>  - Merge panama-vector:vectorIntrinsics+mask into JDK-8266287
>  - Merge panama-vector:vectorIntrinsics+mask into JDK-8266287
>  - Try to reuse the same vector mask IRs
>  - Merge branch panama-vector:vectorIntrinsics+mask' into JDK-8266287
>  - Use "Flag_is_predicated_vector" for masked vector nodes
>  - Merge branch 'vectorIntrinsics+mask'
>  - 8266287: Basic mask IR implementation for the Vector API masking feature support

Marked as reviewed by sviswanathan (Committer).

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PR: https://git.openjdk.java.net/panama-vector/pull/78