[llvm] [InstCombine] Simplify with.overflow intrinsics with assumption information (PR #84016)

[Quentin Dian via llvm-commits]

DianQK wrote:

Hmm, this is the first step, and we still need subsequent PRs to complete this simplification.
(In fact, there's a problem here that cannot be solved for now. We cannot do this in std or core library.

https://github.com/llvm/llvm-project/pull/84016