[llvm] [WIP][Uniformity Analysis][Assume] Generic assume-based uniformity optimization (PR #160670)

[Sameer Sahasrabuddhe via llvm-commits]

ssahasra wrote:

> Isn't the ballot result anded with exec? Such that this assume is only correct for full dispatches at the entry to the kernel?

AMDGPU backend only cares about uniformity within the active lanes of a wave. I didn't really understand the second sentence.

https://github.com/llvm/llvm-project/pull/160670