[llvm] [DA] Add tests for nsw doesn't hold on entier iteration (PR #162281)

[Ehsan Amiri via llvm-commits]

amehsan wrote:

> If you intend to continue this one, I'd strongly recommend creating a new PR/Issue and moving the discussion there. It seems this is no longer closely related to the original issue I raised. I'd like to go back to the original topic.

Will do, but right now, my very next step is to debug your example very carefully and study the test that gave the wrong result. This is because after posting the previous comment, I thought again and I suspect my proof is correct and it seems extensible to weak-crossing and weak-zero as well. So after debugging your example and possibly posting an update here about my findings I will create a new issue. 

https://github.com/llvm/llvm-project/pull/162281