[llvm] [AArch64][SVE] Lower scalar FP converts to SVE when Neon is unavailable (PR #112564)

[Paul Walker via llvm-commits]

https://github.com/paulwalker-arm commented:

To me this looks more like a DAGCombine rather than a lowering problem.  You're essentially saying `fp_op->gpr->fpr` should be rewritten as `new_fp_op` when possible.

https://github.com/llvm/llvm-project/pull/112564