[pypy-dev] memory leak in pypy

[Nathan Hurst]

I was playing with this simple function to compute uint/3.  It does
not (afaict) directly allocate any memory, but when run it rapidly
consumes all memory (32GB):

def divu3(n):
    q = (n >> 2) + (n >> 4)  # q = n*0.0101 (approx).
    q = q + (q >> 4)  # q = n*0.01010101.
    q = q + (q >> 8)  # q = n*0.01010101.
    q = q + (q >> 16)  # q = n*0.01010101.
    r = n - q*3  # 0 <= r <= 15.
    return q + (11*r >> 5)  # Returning q + r/3.


for i in range(2**31):
    assert(divu3(i) == i/3)


Python 2.7.3 (daf1b0412bfbd0666c19d567e37b29e4a3be5734, Jul 12 2013, 19:10:57)
[PyPy 2.1.0-beta1 with GCC 4.7.2] on linux2

is it being over eager to specialise?

njh