Index: include/llvm/Support/AlignOf.h
===================================================================
--- include/llvm/Support/AlignOf.h
+++ include/llvm/Support/AlignOf.h
@@ -58,6 +58,24 @@
   ~AlignmentCalcImpl() override = 0;
 };
 
+template <typename T> struct AlignOfImplOne {
+  enum {
+    Alignment = static_cast<unsigned>(sizeof(AlignmentCalcImpl<T>) - sizeof(T))
+  };
+};
+
+template <typename T, typename... Ts> struct AlignOfImpl {
+  enum {
+    X = AlignOfImplOne<T>::Alignment,
+    Y = AlignOfImpl<Ts...>::Alignment,
+    Alignment = (X > Y) ? X : Y
+  };
+};
+
+template <typename T> struct AlignOfImpl<T> {
+  enum { Alignment = AlignOfImplOne<T>::Alignment };
+};
+
 } // End detail namespace.
 
 /// AlignOf - A templated class that contains an enum value representing
@@ -67,27 +85,22 @@
 ///  the "desired" alignment returned by GCC's __alignof__ (for example).  Note
 ///  that because the alignment is an enum value, it can be used as a
 ///  compile-time constant (e.g., for template instantiation).
-template <typename T>
-struct AlignOf {
+template <typename... Ts> struct AlignOf {
 #ifndef _MSC_VER
   // Avoid warnings from GCC like:
   //   comparison between 'enum llvm::AlignOf<X>::<anonymous>' and 'enum
   //   llvm::AlignOf<Y>::<anonymous>' [-Wenum-compare]
   // by using constexpr instead of enum.
   // (except on MSVC, since it doesn't support constexpr yet).
-  static constexpr unsigned Alignment = static_cast<unsigned int>(
-      sizeof(detail::AlignmentCalcImpl<T>) - sizeof(T));
+  static constexpr unsigned Alignment = detail::AlignOfImpl<Ts...>::Alignment;
 #else
-  enum {
-    Alignment = static_cast<unsigned int>(
-        sizeof(::llvm::detail::AlignmentCalcImpl<T>) - sizeof(T))
-  };
+  enum { Alignment = detail::AlignOfImpl<Ts...>::Alignment };
 #endif
+
   enum { Alignment_GreaterEqual_2Bytes = Alignment >= 2 ? 1 : 0 };
   enum { Alignment_GreaterEqual_4Bytes = Alignment >= 4 ? 1 : 0 };
   enum { Alignment_GreaterEqual_8Bytes = Alignment >= 8 ? 1 : 0 };
   enum { Alignment_GreaterEqual_16Bytes = Alignment >= 16 ? 1 : 0 };
-
   enum { Alignment_LessEqual_2Bytes = Alignment <= 2 ? 1 : 0 };
   enum { Alignment_LessEqual_4Bytes = Alignment <= 4 ? 1 : 0 };
   enum { Alignment_LessEqual_8Bytes = Alignment <= 8 ? 1 : 0 };
@@ -95,15 +108,16 @@
 };
 
 #ifndef _MSC_VER
-template <typename T> constexpr unsigned AlignOf<T>::Alignment;
+template <typename... Ts> constexpr unsigned AlignOf<Ts...>::Alignment;
 #endif
 
 /// alignOf - A templated function that returns the minimum alignment of
 ///  of a type.  This provides no extra functionality beyond the AlignOf
 ///  class besides some cosmetic cleanliness.  Example usage:
 ///  alignOf<int>() returns the alignment of an int.
-template <typename T>
-inline unsigned alignOf() { return AlignOf<T>::Alignment; }
+template <typename... Ts> inline unsigned alignOf() {
+  return AlignOf<Ts...>::Alignment;
+}
 
 /// \struct AlignedCharArray
 /// \brief Helper for building an aligned character array type.
@@ -216,24 +230,16 @@
 #endif // _MSC_VER
 
 namespace detail {
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-class AlignerImpl {
-  T1 t1; T2 t2; T3 t3; T4 t4; T5 t5; T6 t6; T7 t7; T8 t8; T9 t9; T10 t10;
-
-  AlignerImpl() = delete;
+template <typename T, typename... Ts> struct SizerImpl {
+  enum {
+    X = sizeof(T),
+    Y = SizerImpl<Ts...>::SizeOf,
+    SizeOf = (X > Y) ? X : Y
+  };
 };
 
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-union SizerImpl {
-  char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)],
-       arr5[sizeof(T5)], arr6[sizeof(T6)], arr7[sizeof(T7)], arr8[sizeof(T8)],
-       arr9[sizeof(T9)], arr10[sizeof(T10)];
+template <typename T> struct SizerImpl<T> {
+  enum { SizeOf = sizeof(T) };
 };
 } // end namespace detail
 
@@ -242,18 +248,11 @@
 ///
 /// These types may be arrays, structs, or any other types. The goal is to
 /// expose a char array buffer member which can be used as suitable storage for
-/// a placement new of any of these types. Support for more than ten types can
-/// be added at the cost of more boilerplate.
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-struct AlignedCharArrayUnion : llvm::AlignedCharArray<
-    AlignOf<llvm::detail::AlignerImpl<T1, T2, T3, T4, T5,
-                                      T6, T7, T8, T9, T10> >::Alignment,
-    sizeof(::llvm::detail::SizerImpl<T1, T2, T3, T4, T5,
-                                     T6, T7, T8, T9, T10>)> {
-};
+/// a placement new of any of these types.
+template <typename... Ts>
+using AlignedCharArrayUnion =
+    llvm::AlignedCharArray<AlignOf<Ts...>::Alignment,
+                           llvm::detail::SizerImpl<Ts...>::SizeOf>;
 } // end namespace llvm
 
 #endif // LLVM_SUPPORT_ALIGNOF_H
Index: include/llvm/Support/TrailingObjects.h
===================================================================
--- include/llvm/Support/TrailingObjects.h
+++ include/llvm/Support/TrailingObjects.h
@@ -57,26 +57,6 @@
 namespace llvm {
 
 namespace trailing_objects_internal {
-/// Helper template to calculate the max alignment requirement for a set of
-/// objects.
-template <typename First, typename... Rest> class AlignmentCalcHelper {
-private:
-  enum {
-    FirstAlignment = AlignOf<First>::Alignment,
-    RestAlignment = AlignmentCalcHelper<Rest...>::Alignment,
-  };
-
-public:
-  enum {
-    Alignment = FirstAlignment > RestAlignment ? FirstAlignment : RestAlignment
-  };
-};
-
-template <typename First> class AlignmentCalcHelper<First> {
-public:
-  enum { Alignment = AlignOf<First>::Alignment };
-};
-
 /// The base class for TrailingObjects* classes.
 class TrailingObjectsBase {
 protected:
@@ -228,11 +208,10 @@
 /// See the file comment for details on the usage of the
 /// TrailingObjects type.
 template <typename BaseTy, typename... TrailingTys>
-class TrailingObjects : private trailing_objects_internal::TrailingObjectsImpl<
-                            trailing_objects_internal::AlignmentCalcHelper<
-                                TrailingTys...>::Alignment,
-                            BaseTy, TrailingObjects<BaseTy, TrailingTys...>,
-                            BaseTy, TrailingTys...> {
+class TrailingObjects
+    : private trailing_objects_internal::TrailingObjectsImpl<
+          AlignOf<TrailingTys...>::Alignment, BaseTy,
+          TrailingObjects<BaseTy, TrailingTys...>, BaseTy, TrailingTys...> {
 
   template <int A, typename B, typename T, typename P, typename... M>
   friend struct trailing_objects_internal::TrailingObjectsImpl;
@@ -240,8 +219,8 @@
   template <typename... Tys> class Foo {};
 
   typedef trailing_objects_internal::TrailingObjectsImpl<
-      trailing_objects_internal::AlignmentCalcHelper<TrailingTys...>::Alignment,
-      BaseTy, TrailingObjects<BaseTy, TrailingTys...>, BaseTy, TrailingTys...>
+      AlignOf<TrailingTys...>::Alignment, BaseTy,
+      TrailingObjects<BaseTy, TrailingTys...>, BaseTy, TrailingTys...>
       ParentType;
   using TrailingObjectsBase = trailing_objects_internal::TrailingObjectsBase;