[llvm] [ValueTracking] Extend LHS/RHS with matching operand to work without constants. (PR #85557)

[Nikita Popov via llvm-commits]

nikic wrote:

> Rebased, limited CR analysis to MaxRecursiveDepth - 1. My feeling is this is mostly to capture relationships like `X u> Y` implies `X != 0`. Using CR is IMO the easiest way to avoid implementing bespoke logic here.

Using MaxRecursiveDepth - 1 is not particularly useful in this context, because computeConstantRange() is already essentially non-recursive.

This change would be ok if it were free, but it isn't (https://llvm-compile-time-tracker.com/compare.php?from=7d60232b38b66138dae1b31027d73ee5b9df5c58&to=2f155d6f9baacec48a9f69abffbfbca91ef57b46&stat=instructions:u). I don't think that it justifies the cost.

https://github.com/llvm/llvm-project/pull/85557