+namespace {
+struct FindUndefs {
+ bool Found;
+ FindUndefs() : Found(false) {}
+
+ bool follow(const SCEV *S) {
+ if (const SCEVUnknown *C = dyn_cast<SCEVUnknown>(S)) {
+ if (isa<UndefValue>(C->getValue()))
+ Found = true;
+ } else if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
+ if (isa<UndefValue>(C->getValue()))
+ Found = true;
+ }
+
+ // Keep looking if we haven't found it yet.
+ return !Found;
+ }
+ bool isDone() const {
+ // Stop recursion if we have found an undef.
+ return Found;
+ }
+};
+}
+
+// Return true when S contains at least an undef value.
+static inline bool
+containsUndefs(const SCEV *S) {
+ FindUndefs F;
+ SCEVTraversal<FindUndefs> ST(F);
+ ST.visitAll(S);
+
+ return F.Found;
+}
+
+namespace {
+// Collect all steps of SCEV expressions.
+struct SCEVCollectStrides {
+ ScalarEvolution &SE;
+ SmallVectorImpl<const SCEV *> &Strides;
+
+ SCEVCollectStrides(ScalarEvolution &SE, SmallVectorImpl<const SCEV *> &S)
+ : SE(SE), Strides(S) {}
+
+ bool follow(const SCEV *S) {
+ if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
+ Strides.push_back(AR->getStepRecurrence(SE));
+ return true;
+ }
+ bool isDone() const { return false; }
+};
+
+// Collect all SCEVUnknown and SCEVMulExpr expressions.
+struct SCEVCollectTerms {
+ SmallVectorImpl<const SCEV *> &Terms;
+
+ SCEVCollectTerms(SmallVectorImpl<const SCEV *> &T)
+ : Terms(T) {}
+
+ bool follow(const SCEV *S) {
+ if (isa<SCEVUnknown>(S) || isa<SCEVMulExpr>(S)) {
+ if (!containsUndefs(S))
+ Terms.push_back(S);
+
+ // Stop recursion: once we collected a term, do not walk its operands.
+ return false;
+ }
+
+ // Keep looking.
+ return true;
+ }
+ bool isDone() const { return false; }
+};
+}
+
+/// Find parametric terms in this SCEVAddRecExpr.
+void SCEVAddRecExpr::collectParametricTerms(
+ ScalarEvolution &SE, SmallVectorImpl<const SCEV *> &Terms) const {
+ SmallVector<const SCEV *, 4> Strides;
+ SCEVCollectStrides StrideCollector(SE, Strides);
+ visitAll(this, StrideCollector);
+
+ DEBUG({
+ dbgs() << "Strides:\n";
+ for (const SCEV *S : Strides)
+ dbgs() << *S << "\n";
+ });
+
+ for (const SCEV *S : Strides) {
+ SCEVCollectTerms TermCollector(Terms);
+ visitAll(S, TermCollector);
+ }
+
+ DEBUG({
+ dbgs() << "Terms:\n";
+ for (const SCEV *T : Terms)
+ dbgs() << *T << "\n";
+ });
+}
+