Index: /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get.pass.cpp
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get.pass.cpp	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get.pass.cpp	(working copy)
@@ -25,4 +25,14 @@
         assert(c[1] == 5.5);
         assert(c[2] == 3.5);
     }
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        constexpr C c = {1, 2, 3.5};
+        static_assert(std::get<0>(c) == 1, "");
+        static_assert(std::get<1>(c) == 2, "");
+        static_assert(std::get<2>(c) == 3.5, "");
+    }
+#endif
 }
Index: /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get_const.pass.cpp
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get_const.pass.cpp	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/test/containers/sequences/array/array.tuple/get_const.pass.cpp	(working copy)
@@ -24,4 +24,14 @@
         assert(std::get<1>(c) == 2);
         assert(std::get<2>(c) == 3.5);
     }
+#if _LIBCPP_STD_VER > 11
+    {
+        typedef double T;
+        typedef std::array<T, 3> C;
+        constexpr const C c = {1, 2, 3.5};
+        static_assert(std::get<0>(c) == 1, "");
+        static_assert(std::get<1>(c) == 2, "");
+        static_assert(std::get<2>(c) == 3.5, "");
+    }
+#endif
 }
Index: /Users/mclow/Projects/LLVM/libcxx/test/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/test/utilities/utility/pairs/pair.astuple/get_const.pass.cpp	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/test/utilities/utility/pairs/pair.astuple/get_const.pass.cpp	(working copy)
@@ -31,10 +31,8 @@
     {
         typedef std::pair<int, short> P;
         constexpr P p1(3, 4);
-        static_assert(p1.first == 3, "" ); // for now!
-        static_assert(p1.second == 4, "" ); // for now!
-//         static_assert(std::get<0>(p1) == 3, "");
-//         static_assert(std::get<1>(p1) == 4, "");
+        static_assert(std::get<0>(p1) == 3, "");
+        static_assert(std::get<1>(p1) == 4, "");
     }
 #endif
 }
Index: /Users/mclow/Projects/LLVM/libcxx/include/tuple
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/include/tuple	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/include/tuple	(working copy)
@@ -86,13 +86,13 @@
 // 20.4.1.5, element access:
 template <intsize_t I, class... T>
     typename tuple_element<I, tuple<T...>>::type&
-    get(tuple<T...>&) noexcept;
+    get(tuple<T...>&) noexcept; // constexpr in C++14
 template <intsize_t I, class... T>
     typename tuple_element<I, tuple<T...>>::type const&
-    get(const tuple<T...>&) noexcept;
+    get(const tuple<T...>&) noexcept; // constexpr in C++14
 template <intsize_t I, class... T>
     typename tuple_element<I, tuple<T...>>::type&&
-    get(tuple<T...>&&) noexcept;
+    get(tuple<T...>&&) noexcept; // constexpr in C++14
 
 template <class T1, class... T>
     constexpr T1& get(tuple<T...>&) noexcept;  // C++14
@@ -546,11 +546,11 @@
 
     base base_;
 
-    template <size_t _Jp, class ..._Up> friend
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
         typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
-    template <size_t _Jp, class ..._Up> friend
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
         const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
-    template <size_t _Jp, class ..._Up> friend
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
         typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
 public:
 
@@ -763,7 +763,7 @@
 // get
 
 template <size_t _Ip, class ..._Tp>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, tuple<_Tp...> >::type&
 get(tuple<_Tp...>& __t) _NOEXCEPT
 {
@@ -772,7 +772,7 @@
 }
 
 template <size_t _Ip, class ..._Tp>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 const typename tuple_element<_Ip, tuple<_Tp...> >::type&
 get(const tuple<_Tp...>& __t) _NOEXCEPT
 {
@@ -781,7 +781,7 @@
 }
 
 template <size_t _Ip, class ..._Tp>
-inline _LIBCPP_INLINE_VISIBILITY
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, tuple<_Tp...> >::type&&
 get(tuple<_Tp...>&& __t) _NOEXCEPT
 {
Index: /Users/mclow/Projects/LLVM/libcxx/include/utility
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/include/utility	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/include/utility	(working copy)
@@ -546,13 +546,13 @@
 {
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     _T1&
     get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
 
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const _T1&
     get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
 
@@ -560,7 +560,7 @@
 
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     _T1&&
     get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
 
@@ -572,13 +572,13 @@
 {
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     _T2&
     get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
 
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const _T2&
     get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
 
@@ -586,7 +586,7 @@
 
     template <class _T1, class _T2>
     static
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     _T2&&
     get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
 
@@ -594,7 +594,7 @@
 };
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, pair<_T1, _T2> >::type&
 get(pair<_T1, _T2>& __p) _NOEXCEPT
 {
@@ -602,7 +602,7 @@
 }
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
 get(const pair<_T1, _T2>& __p) _NOEXCEPT
 {
@@ -612,7 +612,7 @@
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
 get(pair<_T1, _T2>&& __p) _NOEXCEPT
 {
Index: /Users/mclow/Projects/LLVM/libcxx/include/__tuple
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/include/__tuple	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/include/__tuple	(working copy)
@@ -79,47 +79,47 @@
 template <class _Tp, size_t _Size> struct __tuple_like<array<_Tp, _Size> > : true_type {};
 
 template <size_t _Ip, class ..._Tp>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, tuple<_Tp...> >::type&
 get(tuple<_Tp...>&) _NOEXCEPT;
 
 template <size_t _Ip, class ..._Tp>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 const typename tuple_element<_Ip, tuple<_Tp...> >::type&
 get(const tuple<_Tp...>&) _NOEXCEPT;
 
 template <size_t _Ip, class ..._Tp>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, tuple<_Tp...> >::type&&
 get(tuple<_Tp...>&&) _NOEXCEPT;
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, pair<_T1, _T2> >::type&
 get(pair<_T1, _T2>&) _NOEXCEPT;
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
 get(const pair<_T1, _T2>&) _NOEXCEPT;
 
 template <size_t _Ip, class _T1, class _T2>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
 get(pair<_T1, _T2>&&) _NOEXCEPT;
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 _Tp&
 get(array<_Tp, _Size>&) _NOEXCEPT;
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 const _Tp&
 get(const array<_Tp, _Size>&) _NOEXCEPT;
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
 _Tp&&
 get(array<_Tp, _Size>&&) _NOEXCEPT;
 
Index: /Users/mclow/Projects/LLVM/libcxx/include/array
===================================================================
--- /Users/mclow/Projects/LLVM/libcxx/include/array	(revision 186430)
+++ /Users/mclow/Projects/LLVM/libcxx/include/array	(working copy)
@@ -59,14 +59,14 @@
 
     // element access:
     reference operator[](size_type n);
-    const_reference operator[](size_type n) const;
-    const_reference at(size_type n) const;
+    const_reference operator[](size_type n) const; // constexpr in C++14
+    const_reference at(size_type n) const; // constexpr in C++14
     reference at(size_type n);
 
     reference front();
-    const_reference front() const;
+    const_reference front() const; // constexpr in C++14
     reference back();
-    const_reference back() const;
+    const_reference back() const; // constexpr in C++14
 
     T* data() noexcept;
     const T* data() const noexcept;
@@ -92,9 +92,9 @@
 template <int I, class T> class tuple_element;
 template <class T, size_t N> struct tuple_size<array<T, N>>;
 template <int I, class T, size_t N> struct tuple_element<I, array<T, N>>;
-template <int I, class T, size_t N> T& get(array<T, N>&) noexcept;
-template <int I, class T, size_t N> const T& get(const array<T, N>&) noexcept;
-template <int I, class T, size_t N> T&& get(array<T, N>&&) noexcept;
+template <int I, class T, size_t N> T& get(array<T, N>&) noexcept; // constexpr in C++14
+template <int I, class T, size_t N> const T& get(const array<T, N>&) noexcept; // constexpr in C++14
+template <int I, class T, size_t N> T&& get(array<T, N>&&) noexcept; // constexpr in C++14
 
 }  // std
 
@@ -181,14 +181,14 @@
 
     // element access:
     _LIBCPP_INLINE_VISIBILITY reference operator[](size_type __n)             {return __elems_[__n];}
-    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __n) const {return __elems_[__n];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference operator[](size_type __n) const {return __elems_[__n];}
     reference at(size_type __n);
-    const_reference at(size_type __n) const;
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const;
 
     _LIBCPP_INLINE_VISIBILITY reference front()             {return __elems_[0];}
-    _LIBCPP_INLINE_VISIBILITY const_reference front() const {return __elems_[0];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference front() const {return __elems_[0];}
     _LIBCPP_INLINE_VISIBILITY reference back()              {return __elems_[_Size > 0 ? _Size-1 : 0];}
-    _LIBCPP_INLINE_VISIBILITY const_reference back() const  {return __elems_[_Size > 0 ? _Size-1 : 0];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference back() const  {return __elems_[_Size > 0 ? _Size-1 : 0];}
 
     _LIBCPP_INLINE_VISIBILITY
     value_type* data() _NOEXCEPT {return __elems_;}
@@ -211,6 +211,7 @@
 
 template <class _Tp, size_t _Size>
 typename array<_Tp, _Size>::const_reference
+_LIBCPP_CONSTEXPR_AFTER_CXX11
 array<_Tp, _Size>::at(size_type __n) const
 {
     if (__n >= _Size)
@@ -306,7 +307,7 @@
 };
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 _Tp&
 get(array<_Tp, _Size>& __a) _NOEXCEPT
 {
@@ -315,7 +316,7 @@
 }
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 const _Tp&
 get(const array<_Tp, _Size>& __a) _NOEXCEPT
 {
@@ -326,7 +327,7 @@
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
 
 template <size_t _Ip, class _Tp, size_t _Size>
-_LIBCPP_INLINE_VISIBILITY inline
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR_AFTER_CXX11
 _Tp&&
 get(array<_Tp, _Size>&& __a) _NOEXCEPT
 {