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LWN.net Weekly Edition for May 23, 2013
An "enum" for Python 3
An unexpected perf feature
LWN.net Weekly Edition for May 16, 2013
A look at the PyPy 2.0 release
It is kind of amazing how many non-intuitive optimizations can be made on code like that.
For example, it might be rewritten to something like:
undo using a
or rewritten into two function blocks, one for if (foo) and one for if (!foo).
or the initialization of a might be moved down into the other if (foo) block.
So anyway, it is entirely possible that after GCC swizzles the code around it cannot tell anymore. It might have actually used a without even looking at foo, intending to undo it later.
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