RFR: 8320646: RISC-V: C2 VectorCastHF2F [v3]

[Fei Yang]

On Wed, 28 Feb 2024 14:19:06 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you review this patch to add instrinsics for VectorCastHF2F/VectorCastF2HF?
>> Thanks!
>> 
>> ## Test
>> 
>> test/jdk/java/lang/Float/Binary16ConversionNaN.java
>> test/jdk/java/lang/Float/Binary16Conversion.java
>> 
>> hotspot/jtreg/compiler/intrinsics/float16
>> hotspot/jtreg/compiler/vectorization/TestFloatConversionsVectorjava
>> hotspot/jtreg/compiler/vectorization/TestFloatConversionsVectorNaN.java
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   make UseZvfh experimatal; clean code

src/hotspot/cpu/riscv/c2_MacroAssembler_riscv.cpp line 2037:

> 2035:   __ mv(t0, 26);
> 2036:   // preserve the sign bit.
> 2037:   __ vnsra_wx(tmp, src, t0, Assembler::v0_t);

Will this more simpler version do here? `__ vnsra_wi(tmp, src, 26, Assembler::v0_t);`

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PR Review Comment: https://git.openjdk.org/jdk/pull/17698#discussion_r1510930483