[llvm-branch-commits] [llvm] [AMDGPU] Add synthetic apertures and use them for barriers (PR #204127)

[Matt Arsenault via llvm-branch-commits]

arsenm wrote:

> What is `@llvm.amdgcn.is.shared` supposed to return given an address in a synthetic aperture?

It should return false. I also think whatever we do here should not induce additional costs for it

https://github.com/llvm/llvm-project/pull/204127