[llvm] [X86] LowerSelect - generalize "select icmp(x,0), lhs, rhs" folding patterns. (PR #107272)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

> Drive-by nit: simplifyICmpWithZero from InstructionSimplify.cpp

@tschuett Sorry, but I don't understand what you're pointing me at? simplifyICmpWithZero is about performing value tracking on various ICMP cases in the middle end. This PR is a DAG patch that is trying to recover from the many folds that the likes of TargetLowering::SimplifySetCC can leave us with.

https://github.com/llvm/llvm-project/pull/107272