[llvm] [InstCombine] Fold `(A < B) ^ ((A - B) < 0)` into `ssub.with.overflow` (PR #216590)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> > @llvm.ssub.with.overflow.i8 = global i8 0
> 
> ???

Temporarily filtered out this case. It is not easy to reject globals with intrinsic function names in VerifierPass, as we still allow intrinsic global variables like `@llvm.used`.


https://github.com/llvm/llvm-project/pull/216590