[llvm] [InstCombine] Fold uitofp of masked truncations (PR #222592)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw approved this pull request.

LGTM. I don't have a better idea for generalizing this pattern. Perhaps we can use `canEvaluateZExtd + EvaluateInDifferentType`. But it needs a hint for the wider bit width.


https://github.com/llvm/llvm-project/pull/222592