[llvm] [AArch64] Add bitcasts for lowering saturating add/sub and shift intrinsics. (PR #161840)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

Thanks, I think this LGTM.

@JoshdRod was looking at some of the GISel intrinsics recently. Hopefully that will lower the amount of fallbacks.

https://github.com/llvm/llvm-project/pull/161840