diff --git a/llvm/include/llvm/ADT/Any.h b/llvm/include/llvm/ADT/Any.h
--- a/llvm/include/llvm/ADT/Any.h
+++ b/llvm/include/llvm/ADT/Any.h
@@ -114,27 +114,23 @@
 template <typename T> bool any_isa(const Any &Value) {
   if (!Value.Storage)
     return false;
-  return Value.Storage->id() ==
-         &Any::TypeId<std::remove_cv_t<std::remove_reference_t<T>>>::Id;
+  return Value.Storage->id() == &Any::TypeId<remove_cvref_t<T>>::Id;
 }
 
 template <class T> T any_cast(const Any &Value) {
-  return static_cast<T>(
-      *any_cast<std::remove_cv_t<std::remove_reference_t<T>>>(&Value));
+  return static_cast<T>(*any_cast<remove_cvref_t<T>>(&Value));
 }
 
 template <class T> T any_cast(Any &Value) {
-  return static_cast<T>(
-      *any_cast<std::remove_cv_t<std::remove_reference_t<T>>>(&Value));
+  return static_cast<T>(*any_cast<remove_cvref_t<T>>(&Value));
 }
 
 template <class T> T any_cast(Any &&Value) {
-  return static_cast<T>(std::move(
-      *any_cast<std::remove_cv_t<std::remove_reference_t<T>>>(&Value)));
+  return static_cast<T>(std::move(*any_cast<remove_cvref_t<T>>(&Value)));
 }
 
 template <class T> const T *any_cast(const Any *Value) {
-  using U = std::remove_cv_t<std::remove_reference_t<T>>;
+  using U = remove_cvref_t<T>;
   assert(Value && any_isa<T>(*Value) && "Bad any cast!");
   if (!Value || !any_isa<U>(*Value))
     return nullptr;
diff --git a/llvm/include/llvm/ADT/FunctionExtras.h b/llvm/include/llvm/ADT/FunctionExtras.h
--- a/llvm/include/llvm/ADT/FunctionExtras.h
+++ b/llvm/include/llvm/ADT/FunctionExtras.h
@@ -34,6 +34,7 @@
 
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/STLShims.h"
 #include "llvm/Support/MemAlloc.h"
 #include "llvm/Support/type_traits.h"
 #include <memory>
@@ -60,8 +61,8 @@
     std::enable_if_t<llvm::is_trivially_move_constructible<T>::value &&
                      std::is_trivially_destructible<T>::value>;
 template <typename CallableT, typename ThisT>
-using EnableUnlessSameType = std::enable_if_t<!std::is_same<
-    std::remove_cv_t<std::remove_reference_t<CallableT>>, ThisT>::value>;
+using EnableUnlessSameType =
+    std::enable_if_t<!std::is_same<remove_cvref_t<CallableT>, ThisT>::value>;
 template <typename CallableT, typename Ret, typename... Params>
 using EnableIfCallable =
     std::enable_if_t<std::is_void<Ret>::value ||
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
@@ -186,9 +186,8 @@
   function_ref(
       Callable &&callable,
       // This is not the copy-constructor.
-      std::enable_if_t<
-          !std::is_same<std::remove_cv_t<std::remove_reference_t<Callable>>,
-                        function_ref>::value> * = nullptr,
+      std::enable_if_t<!std::is_same<remove_cvref_t<Callable>,
+                                     function_ref>::value> * = nullptr,
       // Functor must be callable and return a suitable type.
       std::enable_if_t<std::is_void<Ret>::value ||
                        std::is_convertible<decltype(std::declval<Callable>()(
diff --git a/llvm/include/llvm/ADT/STLShims.h b/llvm/include/llvm/ADT/STLShims.h
--- a/llvm/include/llvm/ADT/STLShims.h
+++ b/llvm/include/llvm/ADT/STLShims.h
@@ -42,6 +42,17 @@
 struct disjunction<B1, Bn...>
     : std::conditional<bool(B1::value), B1, disjunction<Bn...>>::type {};
 
+//===----------------------------------------------------------------------===//
+//     Shims for C++20
+//===----------------------------------------------------------------------===//
+
+template <typename T> struct SHIM(remove_cvref) {
+  using type = std::remove_cv_t<std::remove_reference_t<T>>;
+};
+
+template <typename T>
+using SHIM(remove_cvref_t) = typename llvm::remove_cvref<T>::type;
+
 } // namespace llvm
 
 #endif // LLVM_ADT_STLSHIMS_H
diff --git a/llvm/unittests/ADT/STLShimsTest.cpp b/llvm/unittests/ADT/STLShimsTest.cpp
--- a/llvm/unittests/ADT/STLShimsTest.cpp
+++ b/llvm/unittests/ADT/STLShimsTest.cpp
@@ -42,4 +42,21 @@
                                  std::true_type>::value));
 }
 
+TEST(STLShims, RemoveCVRef) {
+#define REMOVE_CVREF_CASE(FROM, TO)                                            \
+  EXPECT_TRUE((std::is_same<llvm::remove_cvref<FROM>::type,                    \
+                            llvm::remove_cvref_t<FROM>>::value));              \
+  EXPECT_TRUE((std::is_same<llvm::remove_cvref_t<FROM>, TO>::value));
+  REMOVE_CVREF_CASE(int, int);
+  REMOVE_CVREF_CASE(int &, int);
+  REMOVE_CVREF_CASE(const int, int);
+  REMOVE_CVREF_CASE(volatile int, int);
+  REMOVE_CVREF_CASE(const volatile int &, int);
+  REMOVE_CVREF_CASE(int *, int *);
+  REMOVE_CVREF_CASE(int *const, int *);
+  REMOVE_CVREF_CASE(const int *, const int *);
+  REMOVE_CVREF_CASE(int *&, int *);
+#undef REMOVE_CVREF_CASE
+}
+
 } // namespace