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

[Nikita Popov via llvm-commits]

nikic wrote:

Yeah, I can't say I'm particularly fond of the direction.

>From the test diffs, a fold we're missing is this: https://alive2.llvm.org/ce/z/-njJr8 Particularly profitable if the new comparison folds later, but also seems generally beneficial.

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