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

[Ehsan Amiri via llvm-commits]

================

----------------
amehsan wrote:

> No. We still need to change the code, since the monotonicity check is currently not performed. Saying that the code has become more complex just because it grew by only 12 lines doesn't make sense, because the logic has changed substantially. Can you please look at the actual content? Even if you really want to discuss LoC, you should also take into account that I removed `absSCEVNoSignedOverflow` and `mulSCEVNoSignedOverflow`, which were only called from Strong SIV.

What prevents us from turning on monotonicity check? Shouldn't it be turned on for correctness reasons? I was talking under the assumption that monotonicity will be turned on before strong SIV is turned on by default.

Will reply to your other comments later.

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