[llvm] [SCEV] Check AR's wrap flags when expanding in non-post increment loops. (PR #77827)

[Florian Hahn via llvm-commits]

fhahn wrote:

> Does this code need to care about post-inc addrecs at all? At this point, we're expanding the (normalized) pre-inc addrec. If we introduce a post-inc use, then we'll explicitly clear the nowrap flags if necessary here (note that it checks S, not Normalized):

Yes I think that should be sufficient. I updated the PR to always check the AddRec flags; to avoid any regressions, I had to do it after the check in the wider type, as the SCEV construction there strengthens flags of some involved AddRecs as unfortunate side effect.

https://github.com/llvm/llvm-project/pull/77827