[llvm] [InstCombine]: Missed Optimization, treat the disjoint Or as an add (PR #86340)

[Shourya Goel via llvm-commits]

Sh0g0-1758 wrote:

@topperc, I was looking at your PR and I realized that most of the work involves running the script on the tests that are not passing and that the work in `InstructionCombining.cpp` is done. If you are still working on your PR, I can shift my work there and we can work on it together?

https://github.com/llvm/llvm-project/pull/86340