+iterator_range<df_iterator<T>> depth_first(const T& G) {
+ return make_range(df_begin(G), df_end(G));
+}
+
+// Provide global definitions of external depth first iterators...
+template <class T, class SetTy = std::set<typename GraphTraits<T>::NodeType*> >
+struct df_ext_iterator : public df_iterator<T, SetTy, true> {
+ df_ext_iterator(const df_iterator<T, SetTy, true> &V)
+ : df_iterator<T, SetTy, true>(V) {}
+};
+
+template <class T, class SetTy>
+df_ext_iterator<T, SetTy> df_ext_begin(const T& G, SetTy &S) {
+ return df_ext_iterator<T, SetTy>::begin(G, S);
+}
+
+template <class T, class SetTy>
+df_ext_iterator<T, SetTy> df_ext_end(const T& G, SetTy &S) {
+ return df_ext_iterator<T, SetTy>::end(G, S);
+}
+
+template <class T, class SetTy>
+iterator_range<df_ext_iterator<T, SetTy>> depth_first_ext(const T& G,
+ SetTy &S) {
+ return make_range(df_ext_begin(G, S), df_ext_end(G, S));
+}
+
+// Provide global definitions of inverse depth first iterators...
+template <class T,
+ class SetTy = llvm::SmallPtrSet<typename GraphTraits<T>::NodeType*, 8>,
+ bool External = false>
+struct idf_iterator : public df_iterator<Inverse<T>, SetTy, External> {
+ idf_iterator(const df_iterator<Inverse<T>, SetTy, External> &V)
+ : df_iterator<Inverse<T>, SetTy, External>(V) {}