Oren Milman added the comment:
I looked at the assembly, and saw maybe_small_long is not inlined, but I agree
that other compilers (or future compilers) might introduce some optimization
that would elide the check.
Also, as expected (thanks to branch prediction, I guess), a little
microbenchmark shows my patch doesn't improve performance:
without my patch:
python.exe -m perf timeit "122 >> 2"
....................
Median +- std dev: 20.5 ns +- 0.5 ns
python.exe -m perf timeit "215 << 1"
....................
Median +- std dev: 20.6 ns +- 0.5 ns
with my patch:
python.exe -m perf timeit "122 >> 2"
....................
Median +- std dev: 20.6 ns +- 0.3 ns
python.exe -m perf timeit "215 << 1"
....................
Median +- std dev: 20.6 ns +- 0.4 ns
----------
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<http://bugs.python.org/issue28272>
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