1 files changed, 24 insertions, 0 deletions
diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index b68345a1dcf..0605e522d7e 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -196,6 +196,30 @@ inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) {
   return mapped_iterator<ItTy, FuncTy>(I, F);
 }
 
+// Returns an iterator_range over the given container which iterates in reverse.
+// Note that the container must have rbegin()/rend() methods for this to work.
+template<typename ContainerTy>
+auto reverse(ContainerTy &C)->decltype(make_range(C.rbegin(), C.rend())) {
+  return make_range(C.rbegin(), C.rend());
+}
+
+// Returns a std::reverse_iterator wrapped around the given iterator.
+template<typename IteratorTy>
+std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
+  return std::reverse_iterator<IteratorTy>(It);
+}
+
+// Returns an iterator_range over the given container which iterates in reverse.
+// Note that the container must have begin()/end() methods which return
+// bidirectional iterators for this to work.
+template<typename ContainerTy>
+auto reverse(ContainerTy &&C)
+  ->decltype(make_range(make_reverse_iterator(std::end(C)),
+                        make_reverse_iterator(std::begin(C)))) {
+  return make_range(make_reverse_iterator(std::end(C)),
+                    make_reverse_iterator(std::begin(C)));
+}
+
 //===----------------------------------------------------------------------===//
 //     Extra additions to <utility>
 //===----------------------------------------------------------------------===//