RFR: 8334078: RISC-V: TestIntVect.java fails after JDK-8332153 when running without RVV

[Gui Cao]

On Fri, 14 Jun 2024 15:54:07 GMT, Gui Cao <gcao at openjdk.org> wrote:

>> Another fix (avoid any potential naming conflict in the future) could be use `CPUInfo.getFeatures()` instead of WHITE_BOX.getCPUFeatures() at:
>> https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/lib/ir_framework/test/IREncodingPrinter.java#L419
>> 
>> The existing checking with WHITE_BOX.getCPUFeatures() is error-prone, I suppose it would break this or that in the future.
>
>> Could there be any naming conflicting in the future? ie. there will be extension named rvd, etc. I'm not sure if the current riscv extension naming convention will avoid this situation, if answer is postive, then it looks good.
> 
> Hi, Thanks for the review.
> As I see it, new riscv extensions are now officially named with a Z prefix, and it's unlikely that rvd will be used for a future extenstion, as it's too ambiguous. Also, I see software like QEMU[1] also uses names like RVI | RVM | RVA | RVF | RVD | RVC elsewhere, so I guess it's not a big problem for us to use rv as a prefix.
> 
> [1] https://github.com/qemu/qemu/blob/046a64b9801343e2e89eef10c7a48eec8d8c0d4f/target/riscv/cpu.c#L436-L442

> Another fix (avoid any potential naming conflict in the future) could be use `CPUInfo.getFeatures()` instead of WHITE_BOX.getCPUFeatures() at: https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/lib/ir_framework/test/IREncodingPrinter.java#L419
> 
> The existing checking with WHITE_BOX.getCPUFeatures() is error-prone, I suppose it would break this or that in the future.

I prefer to use rvv for matching in the tests as I think the current approach (vm.cpu.features ~= ".*v,.*") is error-prone because it's easy for people to ignore the comma which is needed for single-character riscv extensions.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19686#discussion_r1640025760