RFR: JDK-8318228: RISC-V: C2 ConvF2HF [v2]

[Vladimir Kempik]

On Mon, 22 Jan 2024 10:49:38 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you review the patch to add ConvF2HF intrinsic to JDK for riscv？
>> Thanks!
>> 
>> ## Test
>> ### Functionality
>> #### hotspot tests
>> test/hotspot/jtreg/compiler/intrinsics/ 
>> test/hotspot/jtreg/compiler/c2/irTests
>> 
>> #### jdk tests
>> test/jdk/java/lang/Float/Binary16Conversion*.java
>> 
>> ### Performance
>> tested on licheepi.
>> 
>> #### with UseZfh enabled
>> 
>> Benchmark                                     (size)  Mode  Cnt     Score   Error  Units
>> Fp16ConversionBenchmark.floatToFloat16          2048  avgt    2  4170.549          ns/op
>> Fp16ConversionBenchmark.floatToFloat16Memory    2048  avgt    2    21.492          ns/op
>> 
>> 
>> #### with UseZfh disabled
>> (i.e. disable the intrinsic)
>> 
>> Benchmark                                     (size)  Mode  Cnt      Score   Error  Units
>> Fp16ConversionBenchmark.floatToFloat16          2048  avgt    2  25036.647          ns/op
>> Fp16ConversionBenchmark.floatToFloat16Memory    2048  avgt    2     27.326          ns/op
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   replace fclass with feq as performance optimization.

Marked as reviewed by vkempik (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/17450#pullrequestreview-1838161730