[llvm] [AMDGPU] Eliminate likely-spurious execz checks via intrinsic argument (PR #123749)

[Fabian Ritter via llvm-commits]

ritter-x2a wrote:

Closing this PR since it introduces performance regressions. Users can use `__builtin_expect()` or `[[likely]]` where appropriate to avoid execz branches.

https://github.com/llvm/llvm-project/pull/123749