RFR: 8364305: Support AVX10 saturating floating point conversion instructions [v2]

[Mohamed Issa]

On Fri, 29 Aug 2025 23:35:37 GMT, Mohamed Issa <missa at openjdk.org> wrote:

>> @missa-prime Looks like an interesting patch! Do you think you could add some sort of IR test here, to verify that the correct code is generated on AVX10 vs lower AVX?
>
>> @missa-prime Looks like an interesting patch! Do you think you could add some sort of IR test here, to verify that the correct code is generated on AVX10 vs lower AVX?
> 
> @eme64 Thanks for the suggestion. This patch doesn't modify any IR though, so I'm not sure what IR test(s) to add. I could modify existing tests (`test/hotspot/jtreg/compiler/vectorapi/VectorFPtoIntCastTest.java`, `test/hotspot/jtreg/compiler/vectorization/TestFloatConversionsVector.java`, `test/hotspot/jtreg/compiler/vectorization/runner/ArrayTypeConvertTest.java`) that use IR nodes as dependencies though. Would that be sufficient? Or did you have something else in mind?

> @missa-prime Could you not match on the mach graph? See example: `test/hotspot/jtreg/compiler/vectorapi/VectorMultiplyOpt.java` with `CompilePhase.FINAL_CODE`.
> 
> Maybe another `CompilePhase` is better. I have never matched on the mach graph myself, but I wonder if it may be useful here.

I modified existing vector conversion tests, and I'll add some matching scalar tests to get full coverage.

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PR Comment: https://git.openjdk.org/jdk/pull/26919#issuecomment-3260121943