RFR: 8374349: [VectorAPI]: AArch64: Prefer merging mode SVE CPY instruction [v2]

[Andrew Haley]

On Mon, 2 Feb 2026 09:52:31 GMT, Eric Fang <erfang at openjdk.org> wrote:

>> src/hotspot/cpu/aarch64/c2_MacroAssembler_aarch64.cpp line 2846:
>> 
>>> 2844: void C2_MacroAssembler::sve_cpy_optimized(FloatRegister dst, SIMD_RegVariant T,
>>> 2845:                                           PRegister pg, int imm8, bool isMerge) {
>>> 2846:   // When prefer_sve_merging_mode_cpy is enabled, optimize the SVE `cpy
>> 
>> This comment says nothing that is not obvious from the code.
>
> I’d like to briefly document the main idea of this method. How about adding a brief comment before the method like `Provide an optimized implementation for cpy (imm, zeroing) instruction`, or do you think it would be better to remove the comment?

If a comment says nothing that is not obvious from reading the code, the comment should be removed. 

It makes sense to explain why this is better, maybe with reference to documentation elsewhere.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29359#discussion_r2753831979