[llvm] [BDCE] Handle multi-use `select` of `and`s on demanded bits (PR #79688)

[Nikita Popov via llvm-commits]

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

...wat? This should not be looking at selects. You should only be looking at the demanded bits of the and.

https://github.com/llvm/llvm-project/pull/79688