[llvm] [clang] [clang-tools-extra] Improve selection of conditional branch on amdgcn.ballot!=0 condition in SelectionDAG. (PR #68714)

[Nicolai Hähnle via llvm-commits]

nhaehnle wrote:

Though, on second thought, shouldn't there be some wave64 tests?

https://github.com/llvm/llvm-project/pull/68714