Attached patch makes range objects precompute their length on creation.  
This speeds up indexing and len at the expense of a small increase in 
range object size.  The main benefit, however is that unsupported length > 
sys.maxsize is detected early and confusing OverflowError from len(r) or 
r[i] is avoided.

See discussion starting at http://mail.python.org/pipermail/python-
3000/2008-April/013225.html .