return &CouldNotCompute;
}
+namespace {
+ // Helper class working with SCEVTraversal to figure out if a SCEV contains
+ // a SCEVUnknown with null value-pointer. FindInvalidSCEVUnknown::FindOne
+ // is set iff if find such SCEVUnknown.
+ //
+ struct FindInvalidSCEVUnknown {
+ bool FindOne;
+ FindInvalidSCEVUnknown() { FindOne = false; }
+ bool follow(const SCEV *S) {
+ switch (S->getSCEVType()) {
+ case scConstant:
+ return false;
+ case scUnknown:
+ if(!cast<SCEVUnknown>(S)->getValue())
+ FindOne = true;
+ return false;
+ default:
+ return true;
+ }
+ }
+ bool isDone() const { return FindOne; }
+ };
+}
+
+bool ScalarEvolution::checkValidity(const SCEV *S) const {
+ FindInvalidSCEVUnknown F;
+ SCEVTraversal<FindInvalidSCEVUnknown> ST(F);
+ ST.visitAll(S);
+
+ return !F.FindOne;
+}
+
/// getSCEV - Return an existing SCEV if it exists, otherwise analyze the
/// expression and create a new one.
const SCEV *ScalarEvolution::getSCEV(Value *V) {
assert(isSCEVable(V->getType()) && "Value is not SCEVable!");
- ValueExprMapType::const_iterator I = ValueExprMap.find_as(V);
- if (I != ValueExprMap.end()) return I->second;
+ ValueExprMapType::iterator I = ValueExprMap.find_as(V);
+ if (I != ValueExprMap.end()) {
+ const SCEV *S = I->second;
+ if(checkValidity(S))
+ return S;
+ else
+ ValueExprMap.erase(I);
+ }
const SCEV *S = createSCEV(V);
// The process of creating a SCEV for V may have caused other SCEVs