[llvm] InstCombine: Avoid counting uses of constants (PR #136566)

[Matt Arsenault via llvm-commits]

arsenm wrote:

### Merge activity

* **Apr 23, 4:51 AM EDT**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/136566).


https://github.com/llvm/llvm-project/pull/136566