RFR: 8320646: RISC-V: C2 VectorCastHF2F [v7]

[Hamlin Li]

On Thu, 7 Mar 2024 12:19:48 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/vectorization/TestFloatConversionsVector.java line 31:
>> 
>>> 29:  * @requires (os.simpleArch == "x64" & (vm.cpu.features ~= ".*avx512f.*" | vm.cpu.features ~= ".*f16c.*")) |
>>> 30:  *           os.arch == "aarch64" |
>>> 31:  *           (os.arch == "riscv64" & vm.cpu.features ~= ".*zvfh.*")
>> 
>> A small question: I see you used following condition when doing the scalar version:
>>     `(os.arch == "riscv64" & vm.cpu.features ~= ".*zfh,.*")`
>> There is comma there for matching cpu features. Do we really need this comma? It is not there for this vector version.
>
> Seems not necessary currently, unless in the future there is other extension starting with `zfh`, e.g. `zfhX`, but seems that chance is low IMHO.
> And, I think it might not work for the last extension in the CPU feature string if it's with a comma (as the cpu feature string is converted from a list to string, so the last one will not ending with a`,` ? ), so for new and long named extensions, it should be without a comma.

Thanks for testing!

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PR Review Comment: https://git.openjdk.org/jdk/pull/17698#discussion_r1516064255