From what I can see there is no negative impact of the patch on stable macro benchmarks.

There is quite a detectable positive impact on most of integer and float operations from my patch.  13-16% on nbody and spectral_norm benchmarks is still impressive.  And you can see a huge improvement in various timeit micro-benchmarks.

fastint5 is a very compact patch, that only touches the ceval.c file.  It doesn't complicate the code, as the macro is very straightforward.  Since the patch passed the code review, thorough benchmarking and discussion stages, I'd like to commit it.