The previous checkin to clear __slots__ variables did a little bit of

the work each time it found another base class.  All the work is
contiguous, so we might as well do it all at once at the end.

Objects/typeobject.c

@@ -304,7 +304,7 @@ call_finalizer(PyObject *self)
 static void
 subtype_dealloc(PyObject *self)
 {
-	PyTypeObject *type, *base, *temp;
+	PyTypeObject *type, *base;
 	destructor f;
 
 	/* This exists so we can DECREF self->ob_type */
@@ -314,28 +314,28 @@ subtype_dealloc(PyObject *self)
 
 	/* Find the nearest base with a different tp_dealloc */
 	type = self->ob_type;
-	base = type;
+	base = type->tp_base;
 	while ((f = base->tp_dealloc) == subtype_dealloc) {
-		temp = base;
 		base = base->tp_base;
 		assert(base);
-		/* While we're at it, clear __slots__ variables */
-		if (temp->tp_basicsize != base->tp_basicsize &&
-		    temp->tp_itemsize == 0)
-		{
-			char *addr = ((char *)self);
-			char *p = addr + base->tp_basicsize;
-			char *q = addr + temp->tp_basicsize;
-			for (; p < q; p += sizeof(PyObject *)) {
-				PyObject **pp;
-				if (p == addr + type->tp_dictoffset ||
-				    p == addr + type->tp_weaklistoffset)
-					continue;
-				pp = (PyObject **)p;
-				if (*pp != NULL) {
-					Py_DECREF(*pp);
-					*pp = NULL;
-				}
+	}
+
+	/* Clear __slots__ variables */
+	if (type->tp_basicsize != base->tp_basicsize &&
+	    type->tp_itemsize == 0)
+	{
+		char *addr = ((char *)self);
+		char *p = addr + base->tp_basicsize;
+		char *q = addr + type->tp_basicsize;
+		for (; p < q; p += sizeof(PyObject *)) {
+			PyObject **pp;
+			if (p == addr + type->tp_dictoffset ||
+			    p == addr + type->tp_weaklistoffset)
+				continue;
+			pp = (PyObject **)p;
+			if (*pp != NULL) {
+				Py_DECREF(*pp);
+				*pp = NULL;
 			}
 		}
 	}