Index: include/algorithm
===================================================================
--- include/algorithm
+++ include/algorithm
@@ -2497,6 +2497,41 @@
 template <class _ForwardIterator>
 inline _LIBCPP_INLINE_VISIBILITY
 _ForwardIterator
+__buffered__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
+         typename iterator_traits<_ForwardIterator>::value_type* __buff, ptrdiff_t __buff_size)
+{
+    if (__first == __middle)
+        return __last;
+    if (__middle == __last)
+        return __first;
+    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
+    typedef typename _VSTD::iterator_traits<_ForwardIterator>::difference_type difference_type;
+    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type* pointer;
+    difference_type __len1, __len2;
+    __len1 = __middle - __first;
+    __len2 = __last - __middle;
+    if ((__len1 <= __buff_size) && __len1 < __len2) 
+    {
+        pointer __buff_end = __move(__first, __middle,  __buff);
+        __move(__middle, __last, __first);
+        return __move_backward(__buff, __buff_end, __last);
+    }
+    else if (__len2 <= __buff_size)
+    {
+        pointer __buffer_end = __move(__middle, __last,  __buff);
+        __move_backward(__first, __middle, __last);
+        return __move(__buff, __buffer_end, __first);
+    }
+    else
+    {
+        return _VSTD::__rotate(__first, __middle, __last,
+                               typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
+    }
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
 rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
 {
     if (__first == __middle)
@@ -4543,7 +4578,8 @@
         difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
         // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
         // swap middle two partitions
-        __middle = _VSTD::rotate(__m1, __middle, __m2);
+        //__middle = _VSTD::rotate(__m1, __middle, __m2);
+        __middle = _VSTD::__buffered_rotate(__m1, __middle, __m2, __buff, __buff_size);
         // __len12 and __len21 now have swapped meanings
         // merge smaller range with recurisve call and larger with tail recursion elimination
         if (__len11 + __len21 < __len12 + __len22)