diff -r 4e23948f2df2 Objects/descrobject.c
--- a/Objects/descrobject.c	Fri Jan 13 13:25:24 2017 +0200
+++ b/Objects/descrobject.c	Sat Jan 14 14:19:01 2017 +0900
@@ -239,10 +237,22 @@ methoddescr_call(PyMethodDescrObject *de
         return NULL;
     }
 
+    if (descr->d_method->ml_flags == METH_FASTCALL) {
+        // fastcall path
+        if (Py_EnterRecursiveCall(" while calling a Python object")) {
+            return NULL;
+        }
+        fastternaryfunc fastcall = (fastternaryfunc)descr->d_method->ml_meth;
+        PyObject *result = fastcall(self, args + 1, nargs - 1, kwnames);
+        result = _Py_CheckFunctionResult((PyObject*)descr, result, NULL);
+        Py_LeaveRecursiveCall();
+        return result;
+    }
+
     func = PyCFunction_NewEx(descr->d_method, self, NULL);
     if (func == NULL)
         return NULL;
     result = _PyCFunction_FastCallKeywords(func, args + 1, nargs - 1, kwnames);
     Py_DECREF(func);
     return result;
 }
diff -r 4e23948f2df2 Objects/object.c
--- a/Objects/object.c	Fri Jan 13 13:25:24 2017 +0200
+++ b/Objects/object.c	Sat Jan 14 14:19:01 2017 +0900
@@ -1060,7 +1060,9 @@ int
     descr = _PyType_Lookup(tp, name);
     if (descr != NULL) {
         Py_INCREF(descr);
-        if (PyFunction_Check(descr)) {
+        if (PyFunction_Check(descr)
+                || (Py_TYPE(descr) == &PyMethodDescr_Type && 
+                    ((PyMethodDescrObject*)descr)->d_method->ml_flags == METH_FASTCALL)) {
             /* A python method. */
             meth_found = 1;
         } else {