[clang][dataflow] Eliminate code duplication in Environment::createValueUnlessSelfReferential().

[mboehme]

Failing premerge check in CodeGen looks unrelated (this patch doesn't affect CodeGen in any way).

clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp

Value *Environment::createValueUnlessSelfReferential(
   if (Type->isIntegerType()) {
     // FIXME: consider instead `return nullptr`, given that we do nothing useful
     // with integers, and so distinguishing them serves no purpose, but could
     // prevent convergence.
     CreatedValuesCount++;
     return &create<IntegerValue>();
   }
 
-  if (Type->isReferenceType()) {
+  if (Type->isReferenceType() || Type->isPointerType()) {
     CreatedValuesCount++;
-    QualType PointeeType = Type->castAs<ReferenceType>()->getPointeeType();
+    QualType PointeeType = Type->getPointeeType();
     auto &PointeeLoc = createStorageLocation(PointeeType);
 
     if (Visited.insert(PointeeType.getCanonicalType()).second) {
       Value *PointeeVal = createValueUnlessSelfReferential(
           PointeeType, Visited, Depth, CreatedValuesCount);
       Visited.erase(PointeeType.getCanonicalType());
 
       if (PointeeVal != nullptr)
         setValue(PointeeLoc, *PointeeVal);
     }
 
+    if (Type->isReferenceType())
       return &create<ReferenceValue>(PointeeLoc);
-  }
-
-  if (Type->isPointerType()) {
-    CreatedValuesCount++;
-    QualType PointeeType = Type->castAs<PointerType>()->getPointeeType();
-    auto &PointeeLoc = createStorageLocation(PointeeType);
-
-    if (Visited.insert(PointeeType.getCanonicalType()).second) {
-      Value *PointeeVal = createValueUnlessSelfReferential(
-          PointeeType, Visited, Depth, CreatedValuesCount);
-      Visited.erase(PointeeType.getCanonicalType());
-
-      if (PointeeVal != nullptr)
-        setValue(PointeeLoc, *PointeeVal);
-    }
-
+    else
       return &create<PointerValue>(PointeeLoc);
   }
 
   if (Type->isStructureOrClassType() || Type->isUnionType()) {
     CreatedValuesCount++;
     llvm::DenseMap<const ValueDecl *, Value *> FieldValues;
     for (const FieldDecl *Field : DACtx->getReferencedFields(Type)) {
       assert(Field != nullptr);