[llvm] [LLVM] New NoDivergenceSource function attribute (PR #111832)

[Jay Foad via llvm-commits]

jayfoad wrote:

> How is this any different than how we interpret inreg already?

That interpretation of `inreg` is AMDGPU-specific and it only applies to arguments. This is about whether (the return value of) a call is considered always divergent vs only divergent if some of its arguments are.

https://github.com/llvm/llvm-project/pull/111832