while (1) vs. while(True) — Why is there a difference (in python 2 bytecode)?

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In Python 2.x, True is not a keyword, but just a built-in global constant that is defined to 1 in the bool type. Therefore the interpreter still has to load the contents of True. In other words, True is reassignable:

Python 2.7 (r27:82508, Jul  3 2010, 21:12:11) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> True = 4
>>> True
4

In Python 3.x it truly becomes a keyword and a real constant:

Python 3.1.2 (r312:79147, Jul 19 2010, 21:03:37) 
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> True = 4
  File "<stdin>", line 1
SyntaxError: assignment to keyword

thus the interpreter can replace the while True: loop with an infinite loop.

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