[llvm] [AArch64][GlobalISel] Fast-path simple common calls (NFC) (PR #217615)

[Cullen Rhodes via llvm-commits]

c-rhodes wrote:

I will land this soon unless there's any objections. I know fast-paths haven't been well received elsewhere in the GISel pipeline (legalizer, regbankselect) but they seem appropriate for the IRTranslator at least.

https://github.com/llvm/llvm-project/pull/217615