[llvm] [AMDGPU] Preserve LDS waits when demoting single-wave workgroup scope to wavefront (PR #207473)

[Justin Rosner via llvm-commits]

justinrosner wrote:

Closing out this PR as the initial problematic commit was reverted here: https://github.com/llvm/llvm-project/pull/208280

https://github.com/llvm/llvm-project/pull/207473