[llvm] [InstCombine] Replace an integer comparison of a `phi` node with multiple `ucmp`/`scmp` operands and a constant with `phi` of individual comparisons of original intrinsic's arguments (PR #107769)

[Volodymyr Vasylkun via llvm-commits]

Poseydon42 wrote:

> Worth noting that as implemented, the one-use check is also load-bearing for correctness, not just profitability. Otherwise we'd have to make sure we handle multi-edges correctly.

I don't think I quite understand the problem, can you give an example of a test case where removing the one-use check would cause issues?

https://github.com/llvm/llvm-project/pull/107769