[LoopCacheAnalysis] Drop incorrect nowrap flags from addrec (llvm#164796)

This patch stops propagating nowrap flags unconditionally. In the
modified part, when we have an addrec `{%a,+,%b}` where `%b` is known to
be negative, we create a new addrec `{%a,+,(-1 * %b)}`. When creating
it, the nowrap flags are transferred from the original addrec to the new
one without any checks, which is generally incorrect. Since the nowrap
property is not essential for this analysis, it would be better to drop
it to avoid potential bugs.

Author: kasuga-fj

llvm/lib/Analysis/LoopCacheAnalysis.cpp

@@ -436,10 +436,9 @@ bool IndexedReference::delinearize(const LoopInfo &LI) {
       const SCEV *StepRec = AccessFnAR ? AccessFnAR->getStepRecurrence(SE) : nullptr;
 
       if (StepRec && SE.isKnownNegative(StepRec))
-        AccessFn = SE.getAddRecExpr(AccessFnAR->getStart(),
-                                    SE.getNegativeSCEV(StepRec),
-                                    AccessFnAR->getLoop(),
-                                    AccessFnAR->getNoWrapFlags());
+        AccessFn = SE.getAddRecExpr(
+            AccessFnAR->getStart(), SE.getNegativeSCEV(StepRec),
+            AccessFnAR->getLoop(), SCEV::NoWrapFlags::FlagAnyWrap);
       const SCEV *Div = SE.getUDivExactExpr(AccessFn, ElemSize);
       Subscripts.push_back(Div);
       Sizes.push_back(ElemSize);