diff --git a/Doc/lib/libetree.tex b/Doc/lib/libetree.tex
index ffa19435c10..f769c632a42 100644
--- a/Doc/lib/libetree.tex
+++ b/Doc/lib/libetree.tex
@@ -38,10 +38,7 @@ element that will be serialized as an XML comment.
 The comment string can be either an 8-bit ASCII string or a Unicode
 string.
 \var{text} is a string containing the comment string.
-
-\begin{datadescni}{Returns:}
-An element instance, representing a comment.
-\end{datadescni}
+Returns an element instance representing a comment.
 \end{funcdesc}
 
 \begin{funcdesc}{dump}{elem}
@@ -65,28 +62,19 @@ either 8-bit ASCII strings or Unicode strings.
 \var{tag} is the element name.
 \var{attrib} is an optional dictionary, containing element attributes.
 \var{extra} contains additional attributes, given as keyword arguments.
-
-\begin{datadescni}{Returns:}
-An element instance.
-\end{datadescni}
+Returns an element instance.
 \end{funcdesc}
 
 \begin{funcdesc}{fromstring}{text}
 Parses an XML section from a string constant.  Same as XML.
 \var{text} is a string containing XML data.
-
-\begin{datadescni}{Returns:}
-An Element instance.
-\end{datadescni}
+Returns an Element instance.
 \end{funcdesc}
 
 \begin{funcdesc}{iselement}{element}
 Checks if an object appears to be a valid element object.
 \var{element} is an element instance.
-
-\begin{datadescni}{Returns:}
-A true value if this is an element object.
-\end{datadescni}
+Returns a true value if this is an element object.
 \end{funcdesc}
 
 \begin{funcdesc}{iterparse}{source\optional{, events}}
@@ -95,10 +83,7 @@ what's going on to the user.
 \var{source} is a filename or file object containing XML data.
 \var{events} is a list of events to report back.  If omitted, only ``end''
 events are reported.
-
-\begin{datadescni}{Returns:}
-A (event, elem) iterator.
-\end{datadescni}
+Returns an iterator providing \code{(\var{event}, \var{elem})} pairs.
 \end{funcdesc}
 
 \begin{funcdesc}{parse}{source\optional{, parser}}
@@ -106,10 +91,7 @@ Parses an XML section into an element tree.
 \var{source} is a filename or file object containing XML data.
 \var{parser} is an optional parser instance.  If not given, the
 standard XMLTreeBuilder parser is used.
-
-\begin{datadescni}{Returns:}
-An ElementTree instance
-\end{datadescni}
+Returns an ElementTree instance.
 \end{funcdesc}
 
 \begin{funcdesc}{ProcessingInstruction}{target\optional{, text}}
@@ -117,13 +99,11 @@ PI element factory.  This factory function creates a special element
 that will be serialized as an XML processing instruction.
 \var{target} is a string containing the PI target.
 \var{text} is a string containing the PI contents, if given.
-
-\begin{datadescni}{Returns:}
-An element instance, representing a PI.
-\end{datadescni}
+Returns an element instance, representing a processing instruction.
 \end{funcdesc}
 
-\begin{funcdesc}{SubElement}{parent, tag\optional{, attrib} \optional{, **extra}}
+\begin{funcdesc}{SubElement}{parent, tag\optional{,
+                             attrib\optional{,  **extra}}}
 Subelement factory.  This function creates an element instance, and
 appends it to an existing element.
 
@@ -133,10 +113,7 @@ either 8-bit ASCII strings or Unicode strings.
 \var{tag} is the subelement name.
 \var{attrib} is an optional dictionary, containing element attributes.
 \var{extra} contains additional attributes, given as keyword arguments.
-
-\begin{datadescni}{Returns:}
-An element instance.
-\end{datadescni}
+Returns an element instance.
 \end{funcdesc}
 
 \begin{funcdesc}{tostring}{element\optional{, encoding}}
@@ -144,33 +121,162 @@ Generates a string representation of an XML element, including all
 subelements.
 \var{element} is an Element instance.
 \var{encoding} is the output encoding (default is US-ASCII).
-
-\begin{datadescni}{Returns:}
-An encoded string containing the XML data.
-\end{datadescni}
+Returns an encoded string containing the XML data.
 \end{funcdesc}
 
 \begin{funcdesc}{XML}{text}
 Parses an XML section from a string constant.  This function can
 be used to embed ``XML literals'' in Python code.
 \var{text} is a string containing XML data.
-
-\begin{datadescni}{Returns:}
-An Element instance.
-\end{datadescni}
+Returns an Element instance.
 \end{funcdesc}
 
 \begin{funcdesc}{XMLID}{text}
 Parses an XML section from a string constant, and also returns
 a dictionary which maps from element id:s to elements.
 \var{text} is a string containing XML data.
-
-\begin{datadescni}{Returns:}
-A tuple containing an Element instance and a dictionary.
-\end{datadescni}
+Returns a tuple containing an Element instance and a dictionary.
 \end{funcdesc}
 
 
+\subsection{The Element Interface\label{elementtree-element-interface}}
+
+Element objects returned by Element or SubElement have the 
+following methods and attributes.
+
+\begin{memberdesc}{tag}
+A string identifying what kind of data this element represents
+(the element type, in other words).
+\end{memberdesc}
+
+\begin{memberdesc}{text}
+The \var{text} attribute can be used to hold additional data
+associated with the element.
+As the name implies this attribute is usually a string but may be any
+application-specific object.
+If the element is created from an XML file the attribute will contain
+any text found between the element tags.
+\end{memberdesc}
+
+\begin{memberdesc}{tail}
+The \var{tail} attribute can be used to hold additional data
+associated with the element.
+This attribute is usually a string but may be any application-specific object.
+If the element is created from an XML file the attribute will contain
+any text found after the element's end tag and before the next tag.
+\end{memberdesc}
+
+\begin{memberdesc}{attrib}
+A dictionary containing the element's attributes.
+Note that while the \var{attrib} value is always a real mutable Python
+dictionary, an ElementTree implementation may choose to use another
+internal representation, and create the dictionary only if someone
+asks for it. To take advantage of such implementations, use the
+dictionary methods below whenever possible.
+\end{memberdesc}
+
+The following dictionary-like methods work on the element attributes.
+
+\begin{methoddesc}{clear}{}
+Resets an element.  This function removes all subelements, clears
+all attributes, and sets the text and tail attributes to None.
+\end{methoddesc}
+
+\begin{methoddesc}{get}{key\optional{, default=None}}
+Gets the element attribute named \var{key}.
+
+Returns the attribute value, or \var{default} if the
+attribute was not found.
+\end{methoddesc}
+
+\begin{methoddesc}{items}{}
+Returns the element attributes as a sequence of (name, value) pairs.
+The attributes are returned in an arbitrary order.
+\end{methoddesc}
+
+\begin{methoddesc}{keys}{}
+Returns the elements attribute names as a list.
+The names are returned in an arbitrary order.
+\end{methoddesc}
+
+\begin{methoddesc}{set}{key, value}
+Set the attribute \var{key} on the element to \var{value}.  
+\end{methoddesc}
+
+The following methods work on the element's children (subelements).
+
+\begin{methoddesc}{append}{subelement}
+Adds the element \var{subelement} to the end of this elements internal list
+of subelements.
+\end{methoddesc}
+
+\begin{methoddesc}{find}{match}
+Finds the first subelement matching \var{match}. 
+\var{match} may be a tag name or path.
+Returns an element instance or \code{None}.
+\end{methoddesc}
+
+\begin{methoddesc}{findall}{match}
+Finds all subelements matching \var{match}. 
+\var{match} may be a tag name or path.
+Returns an iterable yielding all matching elements in document order.
+\end{methoddesc}
+
+\begin{methoddesc}{findtext}{condition\optional{, default=None}}
+Finds text for the first subelement matching \var{condition}. 
+\var{condition} may be a tag name or path.
+Returns the text content of the first matching element, or
+\var{default} if no element was found.  Note that if the
+matching element has no text content an empty string is returned.
+\end{methoddesc}
+
+\begin{methoddesc}{getchildren}{}
+Returns all subelements.  The elements are returned in document order.
+\end{methoddesc}
+
+\begin{methoddesc}{getiterator}{\optional{tag=None}}
+Creates a tree iterator with the current element as the root.  
+The iterator iterates over this element and all elements below it 
+that match the given tag. If tag
+is \code{None} or \code{'*'} then all elements are iterated over.
+Returns an iterable that provides element objects in document (depth first)
+order.
+\end{methoddesc}
+
+\begin{methoddesc}{insert}{index, element}
+Inserts a subelement at the given position in this element.
+\end{methoddesc}
+
+\begin{methoddesc}{makeelement}{tag, attrib}
+Creates a new element object of the same type as this element.
+Do not call this method, use the SubElement factory function instead.
+\end{methoddesc}
+
+\begin{methoddesc}{remove}{subelement}
+Removes \var{subelement} from the element.  
+Unlike the findXXX methods this method compares elements based on 
+the instance identity, not on tag value or contents.
+\end{methoddesc}
+
+Element objects also support the following sequence type methods for
+working with subelements: \method{__delitem__()},
+\method{__getitem__()}, \method{__setitem__()}, \method{__len__()}.
+
+Caution: Because Element objects do not define a
+\method{__nonzero__()} method, elements with no subelements will test
+as \code{False}.
+
+\begin{verbatim}
+element = root.find('foo')
+
+if not element: # careful!
+    print "element not found, or element has no subelements"
+
+if element is None:
+    print "element not found"
+\end{verbatim}
+
+
 \subsection{ElementTree Objects\label{elementtree-elementtree-objects}}
 
 \begin{classdesc}{ElementTree}{\optional{element,} \optional{file}}
@@ -193,21 +299,15 @@ element.  Use with care.
 Finds the first toplevel element with given tag.
 Same as getroot().find(path).
 \var{path} is the element to look for.
-
-\begin{datadescni}{Returns:}
-The first matching element, or None if no element was found.
-\end{datadescni}
+Returns the first matching element, or \code{None} if no element was found.
 \end{methoddesc}
 
 \begin{methoddesc}{findall}{path}
 Finds all toplevel elements with the given tag.
 Same as getroot().findall(path).
 \var{path} is the element to look for.
-
-\begin{datadescni}{Returns:}
-A list or iterator containing all matching elements,
-in section order.
-\end{datadescni}
+Returns a list or iterator containing all matching elements,
+in document order.
 \end{methoddesc}
 
 \begin{methoddesc}{findtext}{path\optional{, default}}
@@ -215,31 +315,20 @@ Finds the element text for the first toplevel element with given
 tag.  Same as getroot().findtext(path).
 \var{path} is the toplevel element to look for.
 \var{default} is the value to return if the element was not found.
-
-\begin{datadescni}{Returns:}
-The text content of the first matching element, or the
+Returns the text content of the first matching element, or the
 default value no element was found.  Note that if the element
 has is found, but has no text content, this method returns an
 empty string.
-\end{datadescni}
 \end{methoddesc}
 
 \begin{methoddesc}{getiterator}{\optional{tag}}
-Creates a tree iterator for the root element.  The iterator loops
+Creates and returns a tree iterator for the root element.  The iterator loops
 over all elements in this tree, in section order.
 \var{tag} is the tag to look for (default is to return all elements)
-
-\begin{datadescni}{Returns:}
-An iterator.
-\end{datadescni}
 \end{methoddesc}
 
 \begin{methoddesc}{getroot}{}
-Gets the root element for this tree.
-
-\begin{datadescni}{Returns:}
-An element instance.
-\end{datadescni}
+Returns the root element for this tree.
 \end{methoddesc}
 
 \begin{methoddesc}{parse}{source\optional{, parser}}
@@ -247,10 +336,7 @@ Loads an external XML section into this element tree.
 \var{source} is a file name or file object.
 \var{parser} is an optional parser instance.  If not given, the
 standard XMLTreeBuilder parser is used.
-
-\begin{datadescni}{Returns:}
-The section root element.
-\end{datadescni}
+Returns the section root element.
 \end{methoddesc}
 
 \begin{methoddesc}{write}{file\optional{, encoding}}
@@ -270,10 +356,7 @@ in the form {\{}uri{\}}local, or, if the tag argument is given,
 the URI part of a QName.
 If \var{tag} is given, the first argument is interpreted as
 an URI, and this argument is interpreted as a local name.
-
-\begin{datadescni}{Returns:}
-An opaque object, representing the QName.
-\end{datadescni}
+\class{QName} instances are opaque.
 \end{classdesc}
 
 
@@ -291,10 +374,7 @@ given.
 \begin{methoddesc}{close}{}
 Flushes the parser buffers, and returns the toplevel documen
 element.
-
-\begin{datadescni}{Returns:}
-An Element instance.
-\end{datadescni}
+Returns an Element instance.
 \end{methoddesc}
 
 \begin{methoddesc}{data}{data}
@@ -306,20 +386,14 @@ containing ASCII text, or a Unicode string.
 \begin{methoddesc}{end}{tag}
 Closes the current element.
 \var{tag} is the element name.
-
-\begin{datadescni}{Returns:}
-The closed element.
-\end{datadescni}
+Returns the closed element.
 \end{methoddesc}
 
 \begin{methoddesc}{start}{tag, attrs}
 Opens a new element.
 \var{tag} is the element name.
 \var{attrs} is a dictionary containing element attributes.
-
-\begin{datadescni}{Returns:}
-The opened element.
-\end{datadescni}
+Returns the opened element.
 \end{methoddesc}
 
 
@@ -336,10 +410,7 @@ instance of the standard TreeBuilder class.
 
 \begin{methoddesc}{close}{}
 Finishes feeding data to the parser.
-
-\begin{datadescni}{Returns:}
-An element structure.
-\end{datadescni}
+Returns an element structure.
 \end{methoddesc}
 
 \begin{methoddesc}{doctype}{name, pubid, system}
@@ -351,6 +422,5 @@ Handles a doctype declaration.
 
 \begin{methoddesc}{feed}{data}
 Feeds data to the parser.
-
 \var{data} is encoded data.
 \end{methoddesc}
diff --git a/Include/dictobject.h b/Include/dictobject.h
index 44b0838e042..ec2e0c82149 100644
--- a/Include/dictobject.h
+++ b/Include/dictobject.h
@@ -90,7 +90,8 @@ struct _dictobject {
 
 PyAPI_DATA(PyTypeObject) PyDict_Type;
 
-#define PyDict_Check(op) PyObject_TypeCheck(op, &PyDict_Type)
+#define PyDict_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_DICT_SUBCLASS)
 #define PyDict_CheckExact(op) ((op)->ob_type == &PyDict_Type)
 
 PyAPI_FUNC(PyObject *) PyDict_New(void);
diff --git a/Include/listobject.h b/Include/listobject.h
index d9012ce93ec..db3124ed56d 100644
--- a/Include/listobject.h
+++ b/Include/listobject.h
@@ -40,7 +40,8 @@ typedef struct {
 
 PyAPI_DATA(PyTypeObject) PyList_Type;
 
-#define PyList_Check(op) PyObject_TypeCheck(op, &PyList_Type)
+#define PyList_Check(op) \
+		PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_LIST_SUBCLASS)
 #define PyList_CheckExact(op) ((op)->ob_type == &PyList_Type)
 
 PyAPI_FUNC(PyObject *) PyList_New(Py_ssize_t size);
diff --git a/Include/longobject.h b/Include/longobject.h
index 7f2cda6f9c7..b7a29b589da 100644
--- a/Include/longobject.h
+++ b/Include/longobject.h
@@ -11,7 +11,8 @@ typedef struct _longobject PyLongObject; /* Revealed in longintrepr.h */
 
 PyAPI_DATA(PyTypeObject) PyLong_Type;
 
-#define PyLong_Check(op) PyObject_TypeCheck(op, &PyLong_Type)
+#define PyLong_Check(op) \
+		PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_LONG_SUBCLASS)
 #define PyLong_CheckExact(op) ((op)->ob_type == &PyLong_Type)
 
 PyAPI_FUNC(PyObject *) PyLong_FromLong(long);
diff --git a/Include/object.h b/Include/object.h
index 0c5fa4263ec..40e52e37147 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -357,7 +357,8 @@ PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */
 PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */
 PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */
 
-#define PyType_Check(op) PyObject_TypeCheck(op, &PyType_Type)
+#define PyType_Check(op) \
+	PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_TYPE_SUBCLASS)
 #define PyType_CheckExact(op) ((op)->ob_type == &PyType_Type)
 
 PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
@@ -469,11 +470,23 @@ given type object has a specified feature.
 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0
 #endif
 
+/* These flags are used to determine if a type is a subclass. */
+#define Py_TPFLAGS_INT_SUBCLASS		(1L<<23)
+#define Py_TPFLAGS_LONG_SUBCLASS	(1L<<24)
+#define Py_TPFLAGS_LIST_SUBCLASS	(1L<<25)
+#define Py_TPFLAGS_TUPLE_SUBCLASS	(1L<<26)
+#define Py_TPFLAGS_STRING_SUBCLASS	(1L<<27)
+#define Py_TPFLAGS_UNICODE_SUBCLASS	(1L<<28)
+#define Py_TPFLAGS_DICT_SUBCLASS	(1L<<29)
+#define Py_TPFLAGS_BASE_EXC_SUBCLASS	(1L<<30)
+#define Py_TPFLAGS_TYPE_SUBCLASS	(1L<<31)
+
 #define Py_TPFLAGS_DEFAULT  ( \
                              Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \
                             0)
 
 #define PyType_HasFeature(t,f)  (((t)->tp_flags & (f)) != 0)
+#define PyType_FastSubclass(t,f)  PyType_HasFeature(t,f)
 
 
 /*
diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index 67f1909d9ee..562af10a42d 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -94,13 +94,12 @@ PyAPI_FUNC(void) PyErr_NormalizeException(PyObject**, PyObject**, PyObject**);
 
 /* */
 
-#define PyExceptionClass_Check(x) \
-	    (PyType_Check((x)) && PyType_IsSubtype(			\
-		     (PyTypeObject*)(x), (PyTypeObject*)PyExc_BaseException))
+#define PyExceptionClass_Check(x)					\
+	(PyType_Check((x)) &&						\
+	 PyType_FastSubclass((PyTypeObject*)(x), Py_TPFLAGS_BASE_EXC_SUBCLASS))
 
-
-#define PyExceptionInstance_Check(x) \
-	 (PyType_IsSubtype((x)->ob_type, (PyTypeObject*)PyExc_BaseException))
+#define PyExceptionInstance_Check(x)			\
+	PyType_FastSubclass((x)->ob_type, Py_TPFLAGS_BASE_EXC_SUBCLASS)
 
 #define PyExceptionClass_Name(x) \
 	 ((char *)(((PyTypeObject*)(x))->tp_name))
diff --git a/Include/stringobject.h b/Include/stringobject.h
index ef8f54510cb..815619345e3 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -55,7 +55,8 @@ typedef struct {
 PyAPI_DATA(PyTypeObject) PyBaseString_Type;
 PyAPI_DATA(PyTypeObject) PyString_Type;
 
-#define PyString_Check(op) PyObject_TypeCheck(op, &PyString_Type)
+#define PyString_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_STRING_SUBCLASS)
 #define PyString_CheckExact(op) ((op)->ob_type == &PyString_Type)
 
 PyAPI_FUNC(PyObject *) PyString_FromStringAndSize(const char *, Py_ssize_t);
diff --git a/Include/tupleobject.h b/Include/tupleobject.h
index 8c37cabdca3..738cea1e97c 100644
--- a/Include/tupleobject.h
+++ b/Include/tupleobject.h
@@ -33,7 +33,8 @@ typedef struct {
 
 PyAPI_DATA(PyTypeObject) PyTuple_Type;
 
-#define PyTuple_Check(op) PyObject_TypeCheck(op, &PyTuple_Type)
+#define PyTuple_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_TUPLE_SUBCLASS)
 #define PyTuple_CheckExact(op) ((op)->ob_type == &PyTuple_Type)
 
 PyAPI_FUNC(PyObject *) PyTuple_New(Py_ssize_t size);
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 33aa185814a..0bad8c32a2b 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -392,7 +392,8 @@ typedef struct {
 
 PyAPI_DATA(PyTypeObject) PyUnicode_Type;
 
-#define PyUnicode_Check(op) PyObject_TypeCheck(op, &PyUnicode_Type)
+#define PyUnicode_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_UNICODE_SUBCLASS)
 #define PyUnicode_CheckExact(op) ((op)->ob_type == &PyUnicode_Type)
 
 /* Fast access macros */
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index ffa7a86fb33..36a18e43e03 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2027,7 +2027,7 @@ PyTypeObject PyDict_Type = {
 	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 9e298f080e6..402bcecfde9 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -300,7 +300,8 @@ static PyTypeObject _PyExc_BaseException = {
     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 31d8130e60b..932b616a7bb 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -1115,7 +1115,8 @@ PyTypeObject PyInt_Type = {
 	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 3108ab4f80c..0cb1a85fb6a 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2683,7 +2683,7 @@ PyTypeObject PyList_Type = {
 	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 834e2c20265..22d4741bcdc 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3643,7 +3643,8 @@ PyTypeObject PyLong_Type = {
 	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 5f6d0a6dd36..d772e74c07e 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -1131,8 +1131,7 @@ string_richcompare(PyStringObject *a, PyStringObject *b, int op)
 		   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 @@ string_richcompare(PyStringObject *a, PyStringObject *b, int op)
 		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 @@ PyTypeObject PyString_Type = {
 	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 @@ void _Py_ReleaseInternedStrings(void)
 	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 @@ void _Py_ReleaseInternedStrings(void)
 	   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 @@ void _Py_ReleaseInternedStrings(void)
 			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 c85b35a6037..dacc3ee36f8 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -669,7 +669,7 @@ PyTypeObject PyTuple_Type = {
 	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 848203e4d70..e626a17f76c 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2205,7 +2205,7 @@ PyTypeObject PyType_Type = {
 	(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 @@ inherit_special(PyTypeObject *type, PyTypeObject *base)
 	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 fbff31b7f9c..4fe4d100316 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -7971,7 +7971,8 @@ PyTypeObject PyUnicode_Type = {
     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 */