[llvm] [AArch64] Add scal_to_vec patterns for rounding nodes (PR #173004)

[David Green via llvm-commits]

davemgreen wrote:

It could maybe be a late combine (canonicalization). It might cause a mess like you said but if we only have one way of doing it then it might help simplify how many variants we need to handle.

https://github.com/llvm/llvm-project/pull/173004