Index: libcxx/include/algorithm
===================================================================
--- libcxx/include/algorithm
+++ libcxx/include/algorithm
@@ -2305,7 +2305,7 @@
 // rotate
 
 template <class _ForwardIterator>
-_ForwardIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
 __rotate_left(_ForwardIterator __first, _ForwardIterator __last)
 {
     typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
@@ -2316,7 +2316,7 @@
 }
 
 template <class _BidirectionalIterator>
-_BidirectionalIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator
 __rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
 {
     typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
@@ -2328,7 +2328,7 @@
 }
 
 template <class _ForwardIterator>
-_ForwardIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
 __rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
 {
     _ForwardIterator __i = __middle;
@@ -2364,7 +2364,7 @@
 
 template<typename _Integral>
 inline _LIBCPP_INLINE_VISIBILITY
-_Integral
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _Integral
 __algo_gcd(_Integral __x, _Integral __y)
 {
     do
@@ -2377,7 +2377,7 @@
 }
 
 template<typename _RandomAccessIterator>
-_RandomAccessIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
 __rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
 {
     typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
@@ -2413,7 +2413,7 @@
 
 template <class _ForwardIterator>
 inline _LIBCPP_INLINE_VISIBILITY
-_ForwardIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
 __rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
          _VSTD::forward_iterator_tag)
 {
@@ -2428,7 +2428,7 @@
 
 template <class _BidirectionalIterator>
 inline _LIBCPP_INLINE_VISIBILITY
-_BidirectionalIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator
 __rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
          _VSTD::bidirectional_iterator_tag)
 {
@@ -2445,7 +2445,7 @@
 
 template <class _RandomAccessIterator>
 inline _LIBCPP_INLINE_VISIBILITY
-_RandomAccessIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
 __rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
          _VSTD::random_access_iterator_tag)
 {
@@ -2463,7 +2463,7 @@
 
 template <class _ForwardIterator>
 inline _LIBCPP_INLINE_VISIBILITY
-_ForwardIterator
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
 rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
 {
     if (__first == __middle)
Index: libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
===================================================================
--- libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
+++ libcxx/test/std/algorithms/alg.modifying.operations/alg.rotate/rotate.pass.cpp
@@ -419,6 +419,25 @@
 
 #endif  // TEST_STD_VER >= 11
 
+#if TEST_STD_VER > 17
+
+template<class Iter>
+constexpr bool test_constexr()
+{
+    int ia[] = {0, 1, 1, 3, 4};
+    const int expected[] = {1, 3, 4, 0, 1};
+    const size_t n = 2;
+    const Iter b = Iter(std::begin(ia));
+    const Iter m = Iter(std::begin(ia) + n);
+    const Iter e = Iter(std::end(ia));
+
+    std::rotate(b, m, e);
+    return std::equal(std::begin(expected), std::end(expected), std::begin(ia));
+}
+
+#endif  // TEST_STD_VER > 17
+
+
 int main(int, char**)
 {
     test<forward_iterator<int*> >();
@@ -435,5 +454,12 @@
 
 #endif
 
+#if TEST_STD_VER > 17
+    static_assert(test_constexr<forward_iterator<int*> >());
+    static_assert(test_constexr<bidirectional_iterator<int*> >());
+    static_assert(test_constexr<random_access_iterator<int*> >());
+    static_assert(test_constexr<int*>());
+#endif  // TEST_STD_VER > 17
+
   return 0;
 }