RFR: 8341781: Improve Min/Max node identities [v2]

[Jasmine Karthikeyan]

On Thu, 31 Oct 2024 14:47:29 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Example:
>> `./test/hotspot/jtreg/compiler/loopopts/superword/TestGeneralizedReductions.java:    @IR(applyIfPlatform = {"riscv64", "true"},`
>
> The usage of these is quite rare - usually we focus more on the CPU features, and not the platform tags ;)

Ah, I was meaning that with `applyIfPlatformOr = {"x64", "true", "aarch64", "true", "riscv64", "true"}` we would still need at least `applyIfCPUFeature = {"avx", true"}` because on x86 we only make Min/MaxF and Min/MaxD with AVX. But that applyIfCPUFeature will check for AVX on aarch64 and riscv64 as well, but will fail because it's not available for those platforms. That's why I suggested the workaround of checking the other CPU features, to make the test at least run on the other platforms. It'd be nice to be able to express platform and CPU feature combinations like with `@requires`, but the use-case here is pretty niche.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21439#discussion_r1824625007