[llvm-branch-commits] [llvm] AMDGPU: Replace unused update.dpp inputs with poison instead of undef (PR #131287)

[Matt Arsenault via llvm-branch-commits]

arsenm wrote:

### Merge activity

* **Mar 18, 6:23 AM EDT**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/131287).


https://github.com/llvm/llvm-project/pull/131287