[pypy-issue] Issue #2104: Pypy3 2.4.0 slower than Python 3.4.2 for a function? (pypy/pypy)

[TheLoneWolfling .]

New issue 2104: Pypy3 2.4.0 slower than Python 3.4.2 for a function?
https://bitbucket.org/pypy/pypy/issues/2104/pypy3-240-slower-than-python-342-for-a

TheLoneWolfling .:

With the following code:


```
#!python

import random, itertools, timeit

def atLeast(a,b,num):
    return sum(x==y for x,y in itertools.zip_longest(reversed(bin(a).partition('b')[-1]), reversed(bin(b).partition('b')[-1]), fillvalue='0')) >= num

print(timeit.timeit(stmt='atLeast(a,b,96)', setup='from __main__ import atLeast\nimport random\na=random.getrandbits(128)\nb=random.getrandbits(128)', number=100000))
```

I get the following:


```

C:\>python -V
Python 3.4.2

C:\>pypy -V
Python 3.2.5 (b2091e973da6, Oct 19 2014, 21:25:51)
[PyPy 2.4.0 with MSC v.1500 32 bit]

C:\>python pypyslow.py
3.167215612926586

C:\>pypy.exe pypyslow.py
3.3733670679044403
```
Note that Pypy is actually *slower* at running this function than stock Python is.

(I am aware that this is a really bad way to write this function, however I know PyPy likes to know about performance regressions. Just because this function is bad doesn't necessarily mean that there aren't any other functions that are well-written that exhibit this same problem.)

May be related to #2100.