[llvm] [AArch64]SIMD fpcvt codegen for rounding nodes (PR #165546)

[David Green via llvm-commits]

davemgreen wrote:

> I have removed the GlobaISel work from this patch to aid the review and will submit it as a separate patch.

That does make thinks clearer, thanks. I think the GISel part is the part that worked better, I'm not sure these will do much use in practice as the bitcast will often be optimized away. They don't look incorrect to me though, so long as A and X are the sensible conversions to use.

https://github.com/llvm/llvm-project/pull/165546