[llvm] [AMDGPU] Constant folding for wave-reduce intrinsics (PR #212755)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw requested changes to this pull request.

A correctness issue was identified by [llvm-hackme](https://github.com/dtcxzyw/llvm-hackme). Please see the [issue comment](https://github.com/llvm/llvm-project/pull/212755#issuecomment-5150993468) for details.

https://github.com/llvm/llvm-project/pull/212755