[llvm] [InstCombine] Improve coverage of `foldSelectValueEquivalence` for non-constants (PR #94719)

[Nikita Popov via llvm-commits]

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

I don't think this is worth the complication. The only part of this I would consider is the `NewOp == V` case, though I'm having some trouble convincing myself that this really can't lead to a combine loop.

https://github.com/llvm/llvm-project/pull/94719