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

[Xiaohong Gong]

On Wed, 14 Apr 2021 20:54:53 GMT, Paul Sandoz <psandoz at openjdk.org> wrote:

> The changes to Java code generally look ok. @iwanowww will know more than I with regards to how this all behaves with C2 e.g. using `null` or some other sentinel, such as a constant mask with all bits set?

Hi @PaulSandoz , thanks for the comments! Yeah, we can also use a `allTrue` constant mask for the non-mask APIs. This seems reasonable, with just a shortage that the compiler needs to generate more codes to check whether the mask is all true or not. Considering the performance, I didn't use this way. Hope @iwanowww can give more advice for this. Thanks!

> There is an awkward set of differences between non-mask and mask for ROR etc. Although most of that would go away if support is in C2. Possibly leaving subtle differences for DIV. I imagine adjustment of other templates will be similar.

Yes, the adjustment of other templates will be similar.

> I am tempted to have a template method for both non-mask and mask. Thus specialized code (that before calling the intrinsic) may be somewhat duplicated before calling `binaryMaskOp`, using a constant for the op -> lambda function, and passing in null or the mask value.

Yeah, that's why I added the `lanewise0` and `lanewise0Template` methods.

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