diff --git a/libcxx/include/memory b/libcxx/include/memory
--- a/libcxx/include/memory
+++ b/libcxx/include/memory
@@ -3921,6 +3921,42 @@
 
     template <class _Up> friend class _LIBCPP_TEMPLATE_VIS shared_ptr;
     template <class _Up> friend class _LIBCPP_TEMPLATE_VIS weak_ptr;
+
+    template<class _Yp, class _Deleter = default_delete<_Yp>,
+                        class _Alloc = typename __shared_ptr_default_allocator<_Yp>::type>
+    static __shared_weak_count*
+    __allocate_shared(_Yp* __p, _Deleter __d = _Deleter(), _Alloc __a = _Alloc())
+    {
+        typedef __shared_ptr_pointer<_Yp*, _Deleter, _Alloc> _CT;
+        typedef typename __allocator_traits_rebind<_Alloc, _CT>::type _A2;
+        typedef __allocator_destructor<_A2> _D2;
+
+        _A2 __a2(__a);
+        unique_ptr<_CT, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
+
+        ::new(static_cast<void*>(_VSTD::addressof(*__hold2.get())))
+            _CT(__p, __d, __a);
+
+        return _VSTD::addressof(*__hold2.release());
+    }
+
+    template<class _Deleter = default_delete<_Tp>,
+             class _Alloc = typename __shared_ptr_default_allocator<_Tp>::type>
+    static __shared_weak_count*
+    __allocate_shared(nullptr_t __p, _Deleter __d = _Deleter(), _Alloc __a = _Alloc())
+    {
+        typedef __shared_ptr_pointer<_Tp*, _Deleter, _Alloc> _CT;
+        typedef typename __allocator_traits_rebind<_Alloc, _CT>::type _A2;
+        typedef __allocator_destructor<_A2> _D2;
+
+        _A2 __a2(__a);
+        unique_ptr<_CT, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
+
+        ::new(static_cast<void*>(_VSTD::addressof(*__hold2.get())))
+            _CT(__p, __d, __a);
+
+        return _VSTD::addressof(*__hold2.release());
+    }
 };
 
 
@@ -3929,18 +3965,14 @@
 _LIBCPP_CONSTEXPR
 shared_ptr<_Tp>::shared_ptr() _NOEXCEPT
     : __ptr_(0),
-      __cntrl_(0)
-{
-}
+      __cntrl_(0) {}
 
 template<class _Tp>
 inline
 _LIBCPP_CONSTEXPR
 shared_ptr<_Tp>::shared_ptr(nullptr_t) _NOEXCEPT
     : __ptr_(0),
-      __cntrl_(0)
-{
-}
+      __cntrl_(0) {}
 
 template<class _Tp>
 template<class _Yp>
@@ -3948,12 +3980,17 @@
                             typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type)
     : __ptr_(__p)
 {
-    unique_ptr<_Yp> __hold(__p);
-    typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
-    typedef __shared_ptr_pointer<_Yp*, default_delete<_Yp>, _AllocT > _CntrlBlk;
-    __cntrl_ = new _CntrlBlk(__p, default_delete<_Yp>(), _AllocT());
-    __hold.release();
-    __enable_weak_this(__p, __p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif  // _LIBCPP_NO_EXCEPTIONS
+      __cntrl_ = __allocate_shared(__p);
+      __enable_weak_this(__p, __p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        default_delete<_Yp>()(__p);
+        throw;
+    }
+#endif  // _LIBCPP_NO_EXCEPTIONS
 }
 
 template<class _Tp>
@@ -3963,17 +4000,12 @@
     : __ptr_(__p)
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    try
-    {
+    try {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
-        typedef __shared_ptr_pointer<_Yp*, _Dp, _AllocT > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__p, __d, _AllocT());
-        __enable_weak_this(__p, __p);
+      __cntrl_ = __allocate_shared(__p, __d);
+      __enable_weak_this(__p, __p);
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    }
-    catch (...)
-    {
+    } catch (...) {
         __d(__p);
         throw;
     }
@@ -3986,16 +4018,11 @@
     : __ptr_(0)
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    try
-    {
+    try {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef typename __shared_ptr_default_allocator<_Tp>::type _AllocT;
-        typedef __shared_ptr_pointer<nullptr_t, _Dp, _AllocT > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__p, __d, _AllocT());
+      __cntrl_ = __allocate_shared(__p, __d);
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    }
-    catch (...)
-    {
+    } catch (...) {
         __d(__p);
         throw;
     }
@@ -4009,22 +4036,12 @@
     : __ptr_(__p)
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    try
-    {
+    try {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef __shared_ptr_pointer<_Yp*, _Dp, _Alloc> _CntrlBlk;
-        typedef typename __allocator_traits_rebind<_Alloc, _CntrlBlk>::type _A2;
-        typedef __allocator_destructor<_A2> _D2;
-        _A2 __a2(__a);
-        unique_ptr<_CntrlBlk, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
-        ::new(static_cast<void*>(_VSTD::addressof(*__hold2.get())))
-            _CntrlBlk(__p, __d, __a);
-        __cntrl_ = _VSTD::addressof(*__hold2.release());
-        __enable_weak_this(__p, __p);
+      __cntrl_ = __allocate_shared(__p, __d, __a);
+      __enable_weak_this(__p, __p);
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    }
-    catch (...)
-    {
+    } catch (...) {
         __d(__p);
         throw;
     }
@@ -4037,21 +4054,11 @@
     : __ptr_(0)
 {
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    try
-    {
+    try {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef __shared_ptr_pointer<nullptr_t, _Dp, _Alloc> _CntrlBlk;
-        typedef typename __allocator_traits_rebind<_Alloc, _CntrlBlk>::type _A2;
-        typedef __allocator_destructor<_A2> _D2;
-        _A2 __a2(__a);
-        unique_ptr<_CntrlBlk, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
-        ::new(static_cast<void*>(_VSTD::addressof(*__hold2.get())))
-            _CntrlBlk(__p, __d, __a);
-        __cntrl_ = _VSTD::addressof(*__hold2.release());
+      __cntrl_ = __allocate_shared(__p, __d, __a);
 #ifndef _LIBCPP_NO_EXCEPTIONS
-    }
-    catch (...)
-    {
+    } catch (...) {
         __d(__p);
         throw;
     }