Does Python optimize low-power functions?
Nick Cash
nick.cash at npcinternational.com
Fri Dec 6 14:32:00 EST 2013
>My question is, what do Python interpreters do with power operators where the power is a small constant, like 2? Do they know to take the shortcut?
Nope:
Python 3.3.0 (default, Sep 25 2013, 19:28:08)
[GCC 4.7.2] on linux2
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>>> import dis
>>> dis.dis(lambda x: x*x)
1 0 LOAD_FAST 0 (x)
3 LOAD_FAST 0 (x)
6 BINARY_MULTIPLY
7 RETURN_VALUE
>>> dis.dis(lambda x: x**2)
1 0 LOAD_FAST 0 (x)
3 LOAD_CONST 1 (2)
6 BINARY_POWER
7 RETURN_VALUE
The reasons why have already been answered, I just wanted to point out that Python makes it extremely easy to check these sorts of things for yourself.
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