[llvm-branch-commits] [llvm] [ValueTracking] Mark mask.beforefirst as propagating poison (PR #234473)

[Nikita Popov via llvm-branch-commits]

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

LG

> If any element in the input vector is poison, the result is poison.

The poison propagation for this intrinsic is not lanewise, but that should be fine, as this is stronger.

https://github.com/llvm/llvm-project/pull/234473