[llvm] [InstCombine] Simplify phi using KnownBits of condition (PR #134712)

[Andreas Jonson via llvm-commits]

andjo403 wrote:

closing as this implementation is wrong and it also feels like this partly reverts the change from https://github.com/llvm/llvm-project/commit/f1106ef6c9d14d5b516ec352279aeee8f9d12818

https://github.com/llvm/llvm-project/pull/134712