Cython taking more time than regular Python

[Peter Otten]

Stefan Behnel wrote:

> Peter Otten schrieb am 19.09.2016 um 14:55:
>> In [7]: %%cython
>> def omega(int n):
>>     cdef long i
>>     cdef long result = 0
>>     for i in range(n): result += i
>>     return result
>>    ...:
>> 
>> In [8]: %timeit omega(100000)
>> 10000 loops, best of 3: 91.6 µs per loop
> 
> Note that this is the worst benchmark ever. Any non-dump C compiler will
> happily apply Young Gauß and calculate the result in constant time.

Is that optimization useful in an actual program or just a way to cheat in 
benchmarks?