diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -290,7 +290,15 @@
     : public iterator_adaptor_base<
              mapped_iterator<ItTy, FuncTy>, ItTy,
              typename std::iterator_traits<ItTy>::iterator_category,
-             typename std::remove_reference<FuncReturnTy>::type> {
+             typename std::remove_reference<FuncReturnTy>::type,
+             typename std::iterator_traits<ItTy>::difference_type,
+             std::conditional_t<
+                 std::is_same<
+                     typename std::remove_reference<FuncReturnTy>::type,
+                     typename std::iterator_traits<ItTy>::value_type>::value,
+                 typename std::iterator_traits<ItTy>::pointer,
+                 typename std::remove_reference<FuncReturnTy>::type *>,
+             FuncReturnTy> {
 public:
   mapped_iterator(ItTy U, FuncTy F)
     : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}