[llvm] [AMD] using divergent/uniform information in ISel of zext (PR #174539)

[Jay Foad via llvm-commits]

jayfoad wrote:

There is some history here. See #59869 and the PRs linked from it. In particular, #69703 was supposed to solve this, but got reverted, but the last comment on it suggests that it could be un-reverted.

https://github.com/llvm/llvm-project/pull/174539