diff --git a/llvm/include/llvm/ADT/ArrayRef.h b/llvm/include/llvm/ADT/ArrayRef.h
--- a/llvm/include/llvm/ADT/ArrayRef.h
+++ b/llvm/include/llvm/ADT/ArrayRef.h
@@ -562,6 +562,41 @@
     return ArrayRef<T>(Arr);
   }
 
+  /// @name MutableArrayRef Deduction guides
+  /// @{
+  /// Deduction guide to construct a `MutableArrayRef` from a single element
+  template <class T> MutableArrayRef(T &OneElt) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a pointer and
+  /// length.
+  template <class T>
+  MutableArrayRef(T *data, size_t length) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a `SmallVector`.
+  template <class T>
+  MutableArrayRef(SmallVectorImpl<T> &Vec) -> MutableArrayRef<T>;
+
+  template <class T, unsigned N>
+  MutableArrayRef(SmallVector<T, N> &Vec) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a `std::vector`.
+  template <class T> MutableArrayRef(std::vector<T> &Vec) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a `std::array`.
+  template <class T, std::size_t N>
+  MutableArrayRef(std::array<T, N> &Vec) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a `MutableArrayRef`
+  /// (no-op) (const).
+  template <class T>
+  MutableArrayRef(const MutableArrayRef<T> &Vec) -> MutableArrayRef<T>;
+
+  /// Deduction guide to construct a `MutableArrayRef` from a C array.
+  template <typename T, size_t N>
+  MutableArrayRef(T (&Arr)[N]) -> MutableArrayRef<T>;
+
+  /// @}
+
   /// Construct a MutableArrayRef from a single element.
   template<typename T>
   MutableArrayRef<T> makeMutableArrayRef(T &OneElt) {