[llvm] ValueTracking: simplify udiv/urem recurrences (PR #108973)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

As far as I can tell, there is no possible sdiv/srem recurrence simplification: with negative values, the result alternates between positive and negative values. I've now implemented just udiv/urem simplification, and I think it is simple enough that the patch should be good.

https://github.com/llvm/llvm-project/pull/108973