RFR: 8320646: RISC-V: C2 VectorCastHF2F

[Ludovic Henry]

On Tue, 6 Feb 2024 21:40:57 GMT, Ludovic Henry <luhenry 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
>
> src/hotspot/cpu/riscv/assembler_riscv.hpp line 1617:
> 
>> 1615:   INSN(vadd_vi,   0b1010111, 0b011, 0b000000);
>> 1616:   INSN(vrsub_vi,  0b1010111, 0b011, 0b000011);
>> 1617:   INSN(vnsra_wi,  0b1010111, 0b011, 0b101101);
> 
> ~~You can put it up with `vnsra_wx` in the "Vector Narrowing Integer Right Shift Instructions" at https://github.com/openjdk/jdk/pull/17698/files#diff-314214875276cd9a11ecdfd52b68403ded286710ba0820461b0b510506f61a33R1528~~

Let's add a comment to make it more clear what these are
Suggestion:


  // Vector Single-Width Floating-Point Add/Subtract Instructions
  INSN(vnsra_wi,  0b1010111, 0b011, 0b101101);

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PR Review Comment: https://git.openjdk.org/jdk/pull/17698#discussion_r1481592353