diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index ffa7a86..36a18e4 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2027,7 +2027,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS,	/* tp_flags */
 	dictionary_doc,				/* tp_doc */
 	dict_traverse,				/* tp_traverse */
 	dict_tp_clear,				/* tp_clear */
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 9e298f0..402bcec 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -300,7 +300,8 @@
     PyObject_GenericGetAttr,    /*tp_getattro*/
     PyObject_GenericSetAttr,    /*tp_setattro*/
     0,                          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,  /*tp_flags*/
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC |
+    	Py_TPFLAGS_BASE_EXC_SUBCLASS,  /*tp_flags*/
     PyDoc_STR("Common base class for all exceptions"), /* tp_doc */
     (traverseproc)BaseException_traverse, /* tp_traverse */
     (inquiry)BaseException_clear, /* tp_clear */
diff --git a/Objects/intobject.c b/Objects/intobject.c
index 31d8130..932b616 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -1115,7 +1115,8 @@
 	PyObject_GenericGetAttr,		/* tp_getattro */
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+		Py_TPFLAGS_INT_SUBCLASS,	/* tp_flags */
 	int_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 3108ab4..0cb1a85 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2683,7 +2683,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LIST_SUBCLASS,	/* tp_flags */
  	list_doc,				/* tp_doc */
  	(traverseproc)list_traverse,		/* tp_traverse */
  	(inquiry)list_clear,			/* tp_clear */
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 834e2c2..22d4741 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3643,7 +3643,8 @@
 	PyObject_GenericGetAttr,		/* tp_getattro */
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+		Py_TPFLAGS_LONG_SUBCLASS,	/* tp_flags */
 	long_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 5f6d0a6..d772e74 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -1131,8 +1131,7 @@
 		   much time, since Py_NE is rarely used.  */
 		if (a->ob_size == b->ob_size
 		    && (a->ob_sval[0] == b->ob_sval[0]
-			&& memcmp(a->ob_sval, b->ob_sval,
-				  a->ob_size) == 0)) {
+			&& memcmp(a->ob_sval, b->ob_sval, a->ob_size) == 0)) {
 			result = Py_True;
 		} else {
 			result = Py_False;
@@ -1145,7 +1144,7 @@
 		c = Py_CHARMASK(*a->ob_sval) - Py_CHARMASK(*b->ob_sval);
 		if (c==0)
 			c = memcmp(a->ob_sval, b->ob_sval, min_len);
-	}else
+	} else
 		c = 0;
 	if (c == 0)
 		c = (len_a < len_b) ? -1 : (len_a > len_b) ? 1 : 0;
@@ -4018,7 +4017,8 @@
 	PyObject_GenericGetAttr,		/* tp_getattro */
 	0,					/* tp_setattro */
 	&string_as_buffer,			/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
+		Py_TPFLAGS_STRING_SUBCLASS,	/* tp_flags */
 	string_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
@@ -4981,6 +4981,7 @@
 	PyObject *keys;
 	PyStringObject *s;
 	Py_ssize_t i, n;
+	Py_ssize_t immortal_size = 0, mortal_size = 0;
 
 	if (interned == NULL || !PyDict_Check(interned))
 		return;
@@ -4995,8 +4996,9 @@
 	   give them their stolen references back, and then clear and DECREF
 	   the interned dict. */
 
-	fprintf(stderr, "releasing interned strings\n");
 	n = PyList_GET_SIZE(keys);
+	fprintf(stderr, "releasing %" PY_FORMAT_SIZE_T "d interned strings\n",
+		n);
 	for (i = 0; i < n; i++) {
 		s = (PyStringObject *) PyList_GET_ITEM(keys, i);
 		switch (s->ob_sstate) {
@@ -5005,15 +5007,20 @@
 			break;
 		case SSTATE_INTERNED_IMMORTAL:
 			s->ob_refcnt += 1;
+			immortal_size += s->ob_size;
 			break;
 		case SSTATE_INTERNED_MORTAL:
 			s->ob_refcnt += 2;
+			mortal_size += s->ob_size;
 			break;
 		default:
 			Py_FatalError("Inconsistent interned string state.");
 		}
 		s->ob_sstate = SSTATE_NOT_INTERNED;
 	}
+	fprintf(stderr, "total size of all interned strings: "
+			"%" PY_FORMAT_SIZE_T "d/%" PY_FORMAT_SIZE_T "d "
+			"mortal/immortal\n", mortal_size, immortal_size);
 	Py_DECREF(keys);
 	PyDict_Clear(interned);
 	Py_DECREF(interned);
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index c85b35a..dacc3ee 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -669,7 +669,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS, /* tp_flags */
 	tuple_doc,				/* tp_doc */
  	(traverseproc)tupletraverse,		/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 848203e..e626a17 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2205,7 +2205,7 @@
 	(setattrofunc)type_setattro,		/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TYPE_SUBCLASS,	/* tp_flags */
 	type_doc,				/* tp_doc */
 	(traverseproc)type_traverse,		/* tp_traverse */
 	(inquiry)type_clear,			/* tp_clear */
@@ -2874,6 +2874,24 @@
 	COPYVAL(tp_itemsize);
 	COPYVAL(tp_weaklistoffset);
 	COPYVAL(tp_dictoffset);
+
+	/* Setup fast subclass flags */
+	if (PyType_IsSubtype(base, (PyTypeObject*)PyExc_BaseException))
+		type->tp_flags |= Py_TPFLAGS_BASE_EXC_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyType_Type))
+		type->tp_flags |= Py_TPFLAGS_TYPE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyLong_Type))
+		type->tp_flags |= Py_TPFLAGS_LONG_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyString_Type))
+		type->tp_flags |= Py_TPFLAGS_STRING_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyUnicode_Type))
+		type->tp_flags |= Py_TPFLAGS_UNICODE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyTuple_Type))
+		type->tp_flags |= Py_TPFLAGS_TUPLE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyList_Type))
+		type->tp_flags |= Py_TPFLAGS_LIST_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyDict_Type))
+		type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
 }
 
 /* Map rich comparison operators to their __xx__ namesakes */
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index fbff31b..4fe4d10 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -7971,7 +7971,8 @@
     PyObject_GenericGetAttr, 		/* tp_getattro */
     0,			 		/* tp_setattro */
     &unicode_as_buffer,			/* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | 
+        Py_TPFLAGS_UNICODE_SUBCLASS,	/* tp_flags */
     unicode_doc,			/* tp_doc */
     0,					/* tp_traverse */
     0,					/* tp_clear */