RFR: 8354242: VectorAPI: combine vector not operation with compare [v2]

[erifan]

On Fri, 25 Apr 2025 09:48:59 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Since this is a platform independent optimization, I tend to use this `@requires` because it's simpler.  If we use `applyIfCPUFeatureOr`, we need to add the same restriction before each test. In addition, if a new architecture supports the vector node, this test may not cover it. What do you think?
>
> I don't see XorVMask implemented on all non-x86 target, like PPC etc..

This is not specifically required on x86, but because this test fails on x86 when `-XX:UseAVX=0` is specified. When `-XX:UseAVX=0` is specified, the sub-graph is like this:
`(XorV (VectorMaskCmp (LoadVector ...)) (Replicate -1))`
It is not an optimization pattern supported by this patch because we don't know what's the comparison op.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2062583790