[pypy-issue] Issue #2770: python 3 code slower with pypy3 (pypy/pypy)

[lesshaste]

New issue 2770: python 3 code slower with pypy3
https://bitbucket.org/pypy/pypy/issues/2770/python-3-code-slower-with-pypy3

lesshaste:

The following code was written by someone called Dennis.

from functools import lru_cache

@lru_cache(maxsize = None)
def haf(matrix):
        n = len(matrix)
        if n == 2: return matrix[0][1]
        h = 0
        for j in range(1, n):
                if matrix[0][j] == 0: continue
                copy = list(matrix)
                del copy[:j+1:j]
                copy = list(zip(*copy))
                del copy[:j+1:j]
                h += matrix[0][j] * haf(tuple(copy))
        return h


If you feed into it the following input (for example):

[[0, -1, 0, 0, -1, 1, 1, -1, 1, -1, -1, 1, 1, 0, 1, 1, 1, 0, 1, -1, -1, 0, 0, -1, -1, 0], [-1, 1, 1, 1, -1, 1, -1, 0, 1, -1, 0, 0, -1, 0, 1, 1, 1, 0, 0, -1, 0, 0, -1, -1, -1, 0], [0, 1, 1, -1, 0, 0, 1, 0, 0, -1, 1, 0, -1, 1, -1, 0, 0, 0, -1, 0, 1, 0, 1, 1, 1, -1], [0, 1, -1, 0, -1, 0, 0, 1, 0, 0, -1, 1, 1, -1, -1, -1, 0, 1, -1, 1, -1, 0, 1, 0, 0, -1], [-1, -1, 0, -1, 1, 0, 1, 0, -1, 1, 1, -1, 0, -1, 0, 1, 1, -1, 0, -1, 1, 0, -1, 1, 1, -1], [1, 1, 0, 0, 0, 0, 0, -1, 1, 0, 0, 1, 0, -1, -1, -1, -1, 0, 0, -1, -1, 1, 1, 0, 1, 0], [1, -1, 1, 0, 1, 0, 0, 1, -1, -1, -1, 1, -1, -1, 0, -1, 1, 0, -1, 0, -1, -1, 0, -1, 0, -1], [-1, 0, 0, 1, 0, -1, 1, 0, 1, 0, 0, -1, -1, -1, 1, 0, 0, 1, -1, 1, 1, 0, -1, 0, -1, 1], [1, 1, 0, 0, -1, 1, -1, 1, 0, 0, -1, -1, -1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1], [-1, -1, -1, 0, 1, 0, -1, 0, 0, 1, -1, 0, 1, 0, 0, 0, -1, -1, 0, -1, 1, 0, -1, -1, -1, 0], [-1, 0, 1, -1, 1, 0, -1, 0, -1, -1, 0, 1, 1, 0, 1, 0, 0, -1, -1, 1, 0, -1, 1, 1, 0, 0], [1, 0, 0, 1, -1, 1, 1, -1, -1, 0, 1, -1, 1, 0, -1, -1, 1, 1, 1, 0, 1, -1, -1, 0, -1, 1], [1, -1, -1, 1, 0, 0, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 0, 0, -1, 0, 0, -1, 1, -1], [0, 0, 1, -1, -1, -1, -1, -1, -1, 0, 0, 0, -1, 1, -1, 0, 1, -1, 0, 0, 1, -1, -1, 1, 1, 1], [1, 1, -1, -1, 0, -1, 0, 1, 1, 0, 1, -1, -1, -1, -1, 1, 1, -1, 0, 1, 1, 0, 0, -1, 0, 1], [1, 1, 0, -1, 1, -1, -1, 0, 1, 0, 0, -1, 1, 0, 1, 1, 0, 1, -1, 1, 1, 1, -1, 1, 1, -1], [1, 1, 0, 0, 1, -1, 1, 0, 1, -1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, -1, 0, 1, 0, 1, 0], [0, 0, 0, 1, -1, 0, 0, 1, 1, -1, -1, 1, -1, -1, -1, 1, 0, 0, -1, -1, 0, 0, 1, 1, 1, 0], [1, 0, -1, -1, 0, 0, -1, -1, -1, 0, -1, 1, 0, 0, 0, -1, 1, -1, -1, 1, 0, 1, -1, 0, -1, -1], [-1, -1, 0, 1, -1, -1, 0, 1, 1, -1, 1, 0, 0, 0, 1, 1, 0, -1, 1, 1, -1, -1, -1, -1, 0, 1], [-1, 0, 1, -1, 1, -1, -1, 1, -1, 1, 0, 1, -1, 1, 1, 1, -1, 0, 0, -1, 1, 1, 1, 1, 0, 0], [0, 0, 0, 0, 0, 1, -1, 0, 1, 0, -1, -1, 0, -1, 0, 1, 0, 0, 1, -1, 1, -1, -1, 1, 1, 1], [0, -1, 1, 1, -1, 1, 0, -1, -1, -1, 1, -1, 0, -1, 0, -1, 1, 1, -1, -1, 1, -1, 0, -1, 0, 0], [-1, -1, 1, 0, 1, 0, -1, 0, 1, -1, 1, 0, -1, 1, -1, 1, 0, 1, 0, -1, 1, 1, -1, 0, 0, -1], [-1, -1, 1, 0, 1, 1, 0, -1, 1, -1, 0, -1, 1, 1, 0, 1, 1, 1, -1, 0, 0, 1, 0, 0, 1, -1], [0, 0, -1, -1, -1, 0, -1, 1, -1, 0, 0, 1, -1, 1, 1, -1, 0, 0, -1, 1, 0, 1, 0, -1, -1, 1]]

it takes about 10 seconds on python3 and about 14 seconds using pypy3.5-5.10.1-linux_x86_64-portable