Index: include/array
===================================================================
--- include/array
+++ include/array
@@ -152,31 +152,31 @@
         { _VSTD::swap_ranges(__elems_, __elems_ + _Size, __a.__elems_);}
 
     // iterators:
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     iterator begin() _NOEXCEPT {return iterator(__elems_);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_iterator begin() const _NOEXCEPT {return const_iterator(__elems_);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     iterator end() _NOEXCEPT {return iterator(__elems_ + _Size);}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_iterator end() const _NOEXCEPT {return const_iterator(__elems_ + _Size);}
 
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_reverse_iterator rbegin() const _NOEXCEPT {return const_reverse_iterator(end());}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_reverse_iterator rend() const _NOEXCEPT {return const_reverse_iterator(begin());}
 
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_iterator cbegin() const _NOEXCEPT {return begin();}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_iterator cend() const _NOEXCEPT {return end();}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const_reverse_iterator crend() const _NOEXCEPT {return rend();}
 
     // capacity:
@@ -188,23 +188,24 @@
     _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {return _Size == 0;}
 
     // element access:
-    _LIBCPP_INLINE_VISIBILITY reference operator[](size_type __n)             {return __elems_[__n];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 reference operator[](size_type __n)             {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);
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 reference at(size_type __n);
     _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const;
 
-    _LIBCPP_INLINE_VISIBILITY reference front()             {return __elems_[0];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 reference front()             {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 _LIBCPP_CONSTEXPR_AFTER_CXX11 reference back()              {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
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     value_type* data() _NOEXCEPT {return __elems_;}
-    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
     const value_type* data() const _NOEXCEPT {return __elems_;}
 };
 
 template <class _Tp, size_t _Size>
+_LIBCPP_CONSTEXPR_AFTER_CXX11
 typename array<_Tp, _Size>::reference
 array<_Tp, _Size>::at(size_type __n)
 {
Index: test/std/containers/sequences/array/relaxed_constexpr_members.pass.cpp
===================================================================
--- /dev/null
+++ test/std/containers/sequences/array/relaxed_constexpr_members.pass.cpp
@@ -0,0 +1,105 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include <array>
+
+#include "test_macros.h"
+
+#if TEST_STD_VER > 11
+
+using array = std::array<int, 3>;
+
+constexpr int test_constexpr_begin() {
+  array ar = {0, 1, 2};
+  array::iterator it = ar.begin();
+  ++it;
+  return *it;
+}
+
+constexpr int test_constexpr_end() {
+  array ar = {0, 1, 2};
+  array::iterator it = ar.end();
+  --it;
+  return *it;
+}
+
+/* rbegin and rend can't be constexpr for now,
+ * because int the libc++ implementation
+ * the type reverse_iterator is not literal
+constexpr int test_constexpr_rbegin()
+{
+    array ar = {0, 1, 2};
+    array::reverse_iterator it = ar.rbegin();
+    ++it;
+    return *it;
+}
+constexpr int test_constexpr_rend()
+{
+    array ar = {0, 1, 2};
+    array::reverse_iterator it = ar.rend();
+    --it;
+    return *it;
+}
+*/
+
+constexpr int test_constexpr_front() {
+  array ar = {0, 1, 2};
+  ++ar.front();
+  return ar[0];
+}
+
+constexpr int test_constexpr_back() {
+  array ar = {0, 1, 2};
+  ++ar.back();
+  return ar[2];
+}
+
+constexpr int test_constexpr_data() {
+  array ar = {0, 1, 2};
+  int *p = ar.data();
+  *++p = 7;
+  return ar[1];
+}
+
+#endif
+
+int main() {
+#if TEST_STD_VER > 11
+  {
+    constexpr int a = test_constexpr_begin();
+    static_assert(a == 1, "");
+
+    constexpr int b = test_constexpr_end();
+    static_assert(b == 2, "");
+  }
+
+  {
+    constexpr array ar = {0, 1, 2};
+
+    constexpr int i1 = ar[1];
+    static_assert(i1 == 1, "");
+
+    constexpr int i2 = ar.at(2);
+    static_assert(i2 == 2, "");
+  }
+
+  {
+    constexpr int a = test_constexpr_front();
+    static_assert(a == 1, "");
+
+    constexpr int b = test_constexpr_back();
+    static_assert(b == 3, "");
+  }
+
+  {
+    constexpr int a = test_constexpr_data();
+    static_assert(a == 7, "");
+  }
+#endif
+}