diff -r c1a698edfa1b Include/abstract.h
--- a/Include/abstract.h	Tue Aug 23 16:22:35 2016 +0200
+++ b/Include/abstract.h	Tue Aug 23 16:53:13 2016 +0200
@@ -292,6 +292,10 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 #define _PyObject_CallArg1(func, arg) \
     _PyObject_FastCall((func), &(arg), 1)
 
+    PyAPI_FUNC(PyObject *) _PyObject_Call_Preprend(PyObject *func,
+                                                   PyObject *obj, PyObject *args,
+                                                   PyObject *kwargs);
+
      PyAPI_FUNC(PyObject *) _Py_CheckFunctionResult(PyObject *func,
                                                     PyObject *result,
                                                     const char *where);
diff -r c1a698edfa1b Objects/abstract.c
--- a/Objects/abstract.c	Tue Aug 23 16:22:35 2016 +0200
+++ b/Objects/abstract.c	Tue Aug 23 16:53:13 2016 +0200
@@ -2309,6 +2309,45 @@ exit:
     return result;
 }
 
+/* Positional arguments are obj followed args. */
+PyObject *
+_PyObject_Call_Preprend(PyObject *func,
+                        PyObject *obj, PyObject *args, PyObject *kwargs)
+{
+    PyObject *small_stack[5];
+    PyObject **stack;
+    Py_ssize_t argcount;
+    PyObject *result;
+
+    assert(PyTuple_Check(args));
+
+    argcount = PyTuple_GET_SIZE(args);
+    if (argcount + 1 <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {
+        stack = small_stack;
+    }
+    else {
+        stack = PyMem_Malloc((argcount + 1) * sizeof(PyObject *));
+        if (stack == NULL) {
+            PyErr_NoMemory();
+            return NULL;
+        }
+    }
+
+    /* use borrowed references */
+    stack[0] = obj;
+    Py_MEMCPY(&stack[1],
+              &PyTuple_GET_ITEM(args, 0),
+              argcount * sizeof(PyObject *));
+
+    result = _PyObject_FastCallDict(func,
+                                    stack, argcount + 1,
+                                    kwargs);
+    if (stack != small_stack) {
+        PyMem_Free(stack);
+    }
+    return result;
+}
+
 static PyObject*
 call_function_tail(PyObject *callable, PyObject *args)
 {
diff -r c1a698edfa1b Objects/classobject.c
--- a/Objects/classobject.c	Tue Aug 23 16:22:35 2016 +0200
+++ b/Objects/classobject.c	Tue Aug 23 16:53:13 2016 +0200
@@ -302,34 +302,19 @@ method_traverse(PyMethodObject *im, visi
 }
 
 static PyObject *
-method_call(PyObject *func, PyObject *arg, PyObject *kw)
+method_call(PyObject *method, PyObject *args, PyObject *kwargs)
 {
-    PyObject *self = PyMethod_GET_SELF(func);
-    PyObject *result;
+    PyObject *self, *func;
 
-    func = PyMethod_GET_FUNCTION(func);
+    self = PyMethod_GET_SELF(method);
     if (self == NULL) {
         PyErr_BadInternalCall();
         return NULL;
     }
-    else {
-        Py_ssize_t argcount = PyTuple_Size(arg);
-        PyObject *newarg = PyTuple_New(argcount + 1);
-        int i;
-        if (newarg == NULL)
-            return NULL;
-        Py_INCREF(self);
-        PyTuple_SET_ITEM(newarg, 0, self);
-        for (i = 0; i < argcount; i++) {
-            PyObject *v = PyTuple_GET_ITEM(arg, i);
-            Py_XINCREF(v);
-            PyTuple_SET_ITEM(newarg, i+1, v);
-        }
-        arg = newarg;
-    }
-    result = PyObject_Call((PyObject *)func, arg, kw);
-    Py_DECREF(arg);
-    return result;
+
+    func = PyMethod_GET_FUNCTION(method);
+
+    return _PyObject_Call_Preprend(func, self, args, kwargs);
 }
 
 static PyObject *
diff -r c1a698edfa1b Objects/typeobject.c
--- a/Objects/typeobject.c	Tue Aug 23 16:22:35 2016 +0200
+++ b/Objects/typeobject.c	Tue Aug 23 16:53:13 2016 +0200
@@ -6357,28 +6357,13 @@ static PyObject *
 slot_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
     PyObject *func;
-    PyObject *newargs, *x;
-    Py_ssize_t i, n;
 
     func = _PyObject_GetAttrId((PyObject *)type, &PyId___new__);
-    if (func == NULL)
+    if (func == NULL) {
         return NULL;
-    assert(PyTuple_Check(args));
-    n = PyTuple_GET_SIZE(args);
-    newargs = PyTuple_New(n+1);
-    if (newargs == NULL)
-        return NULL;
-    Py_INCREF(type);
-    PyTuple_SET_ITEM(newargs, 0, (PyObject *)type);
-    for (i = 0; i < n; i++) {
-        x = PyTuple_GET_ITEM(args, i);
-        Py_INCREF(x);
-        PyTuple_SET_ITEM(newargs, i+1, x);
-    }
-    x = PyObject_Call(func, newargs, kwds);
-    Py_DECREF(newargs);
-    Py_DECREF(func);
-    return x;
+    }
+
+    return _PyObject_Call_Preprend(func, (PyObject *)type, args, kwds);
 }
 
 static void