At the moment, proveNoWrapViaConstantRanges is only used when creating
SCEV[Zero,Sign]ExtendExprs. We can get significant improvements by
strengthening flags after creating the AddRec.
I'll also share a follow-up patch that removes the code to strengthen
flags when creating SCEV[Zero,Sign]ExtendExprs. Modifying AddRecs while
creating those can lead to surprising changes.
Compile-time looks neutral:
https://llvm-compile-time-tracker.com/compare.php?from=94676cf8a13c511a9acfc24ed53c98964a87bde3&to=aced434e8b103109104882776824c4136c90030d&stat=instructions:u
Should we update Flags here to have more optimistic flags for BEInst?