RFR: 8369456: [TESTBUG] Fix the test failure of TestSelectFromTwoVectorOp.java on sve2 platforms [v2]

[erifan]

On Fri, 31 Oct 2025 01:18:00 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

>> Hi @eme64 thanks for your review. As the vector species is fixed `ByteVector.SPECIES_512`, removing `IRNode.VECTOR_SIZE_64` doesn't work. Adding a rule for cases where `MaxVectorSize > 64` makes sense to me. I'll add the rule in the next commit, thanks~
>
> I'm afraid that there is not a machine which really runs with `MaxVectorSize > 64` both on X86 and AArch64.  Can we just check the `MaxVectorSize = 64` case?

Yes, we currently do not have any >128 bits SVE2 machines. According to  https://github.com/openjdk/jdk/blob/4f9f086847f531ab1791727d74955cfd8ec56811/src/hotspot/cpu/aarch64/aarch64_vector.ad#L273 these cases are currently unsupported. This is why the test failed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27723#discussion_r2479973852