Index: include/memory
===================================================================
--- include/memory
+++ include/memory
@@ -3884,13 +3884,25 @@
             }
         }
 
-    _LIBCPP_INLINE_VISIBILITY
-    void __enable_weak_this(const volatile void*, const volatile void*) _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY void __enable_weak_this(...) _NOEXCEPT {}
 
     template <class _Up> friend class _LIBCPP_TEMPLATE_VIS shared_ptr;
     template <class _Up> friend class _LIBCPP_TEMPLATE_VIS weak_ptr;
 };
 
+template <class _Tp, bool = is_function<_Tp>::value>
+struct __shared_ptr_default_allocator;
+
+template <class _Tp> struct __shared_ptr_default_allocator<_Tp, false>
+{
+    typedef allocator<_Tp> type;
+};
+
+template <class _Tp> struct __shared_ptr_default_allocator<_Tp, true>
+{
+    typedef allocator<int> type;
+};
+
 template<class _Tp>
 inline
 _LIBCPP_CONSTEXPR
@@ -3916,8 +3928,9 @@
     : __ptr_(__p)
 {
     unique_ptr<_Yp> __hold(__p);
-    typedef __shared_ptr_pointer<_Yp*, default_delete<_Yp>, allocator<_Yp> > _CntrlBlk;
-    __cntrl_ = new _CntrlBlk(__p, default_delete<_Yp>(), allocator<_Yp>());
+    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);
 }
@@ -3932,8 +3945,9 @@
     try
     {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef __shared_ptr_pointer<_Yp*, _Dp, allocator<_Yp> > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__p, __d, allocator<_Yp>());
+        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);
 #ifndef _LIBCPP_NO_EXCEPTIONS
     }
@@ -3954,8 +3968,9 @@
     try
     {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-        typedef __shared_ptr_pointer<nullptr_t, _Dp, allocator<_Tp> > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__p, __d, allocator<_Tp>());
+        typedef typename __shared_ptr_default_allocator<_Tp>::type _AllocT;
+        typedef __shared_ptr_pointer<nullptr_t, _Dp, _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__p, __d, _AllocT());
 #ifndef _LIBCPP_NO_EXCEPTIONS
     }
     catch (...)
@@ -4094,8 +4109,9 @@
                             typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type)
     : __ptr_(__r.get())
 {
-    typedef __shared_ptr_pointer<_Yp*, default_delete<_Yp>, allocator<_Yp> > _CntrlBlk;
-    __cntrl_ = new _CntrlBlk(__r.get(), default_delete<_Yp>(), allocator<_Yp>());
+    typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+    typedef __shared_ptr_pointer<_Yp*, default_delete<_Yp>, _AllocT > _CntrlBlk;
+    __cntrl_ = new _CntrlBlk(__r.get(), default_delete<_Yp>(), _AllocT());
     __enable_weak_this(__r.get(), __r.get());
     __r.release();
 }
@@ -4123,8 +4139,9 @@
     else
 #endif
     {
-        typedef __shared_ptr_pointer<_Yp*, _Dp, allocator<_Yp> > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__r.get(), __r.get_deleter(), allocator<_Yp>());
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+        typedef __shared_ptr_pointer<_Yp*, _Dp, _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__r.get(), __r.get_deleter(), _AllocT());
         __enable_weak_this(__r.get(), __r.get());
     }
     __r.release();
@@ -4152,10 +4169,11 @@
     else
 #endif
     {
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
         typedef __shared_ptr_pointer<_Yp*,
                                      reference_wrapper<typename remove_reference<_Dp>::type>,
-                                     allocator<_Yp> > _CntrlBlk;
-        __cntrl_ = new _CntrlBlk(__r.get(), ref(__r.get_deleter()), allocator<_Yp>());
+                                     _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__r.get(), ref(__r.get_deleter()), _AllocT());
         __enable_weak_this(__r.get(), __r.get());
     }
     __r.release();
Index: test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
===================================================================
--- test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
+++ test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
@@ -45,6 +45,13 @@
     virtual ~Foo() = default;
 };
 
+struct Result {};
+static Result theFunction() { return Result(); }
+static int resultDeletorCount;
+static void resultDeletor(Result (*pf)()) {
+  assert(pf == theFunction);
+  ++resultDeletorCount;
+}
 
 int main()
 {
@@ -65,7 +72,11 @@
     std::shared_ptr<const Foo> p2 = std::make_shared<const Foo>();
     assert(p2.get());
     }
-
+    { // https://bugs.llvm.org/show_bug.cgi?id=27566
+      std::shared_ptr<Result()> x(&theFunction, &resultDeletor);
+      std::shared_ptr<Result()> y(theFunction, resultDeletor);
+    }
+    assert(resultDeletorCount == 2);
 #if TEST_STD_VER >= 11
     nc = globalMemCounter.outstanding_new;
     {