RFR: 8321010: RISC-V: C2 RoundVF

[Vladimir Kempik]

On Wed, 7 Feb 2024 09:58:35 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Hi,
> Can you have a review on this patch to add RoundVF/RoundDF intrinsics?
> Thanks!
> 
> ## Tests
> 
> test/hotspot/jtreg/compiler/vectorization/TestRoundVectRiscv64.java test/hotspot/jtreg/compiler/c2/cr6340864/TestFloatVect.java test/hotspot/jtreg/compiler/c2/cr6340864/TestDoubleVect.java test/hotspot/jtreg/compiler/floatingpoint/TestRound.java
> 
> test/jdk/java/lang/Math/RoundTests.java

Hello Hamlin, I recall you had licheepi board.
I would be nice if you can try to measure rvv performance gain with this https://github.com/syntacore/syntaj21/tree/rvv0.7.1

This PR showed it's not always easy to win perf just by using rvv - https://github.com/openjdk/jdk/pull/17413

I understand it might not be possible, but would be nice to give it a try (I can share hsdis with support for 0.7.1 if needed)

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PR Comment: https://git.openjdk.org/jdk/pull/17745#issuecomment-1932131615