Question

This is a simple program written to solve CodeJam’s recycled numbers (I know it can be improved).

It works with CPython, but crashes with PyPy v1.8 with the error:

RPython traceback:
  File "jit_metainterp_compile.c", line 19477, in send_loop_to_backend
  File "jit_backend_x86_assembler.c", line 2293, in Assembler386_assemble_loop
  File "jit_backend_x86_regalloc.c", line 462, in RegAlloc_prepare_loop
  File "jit_backend_x86_regalloc.c", line 1027, in RegAlloc__prepare
  File "jit_backend_x86_regalloc.c", line 3657, in RegAlloc__compute_vars_longevity
Fatal RPython error: AssertionError
[1]    8440 abort      pypy cj.py

Code:

#!/usr/bin/env python2

def permutations(a,b,x):

    y = str(x)
    cnt = 0
    for i in range(1,len(y)):
        j = int(y[i:]+y[:i])
        if j == x:
            break
        elif j > x and j >= a and j <= b:
            cnt += 1

    return cnt

nc = int(raw_input())
for c in xrange(nc):
    a, b = map(int,raw_input().split())

    cnt = 0
    for i in range(a,b+1):
        cnt += permutations(a,b,i)

    print "Case #%i: %i" % (c+1, cnt)

Sample Input:

4
1 9
10 40
100 500
1111 2222

Answer 1

That looks like a bug. Indeed, it may be related to this bug report:

https://bitbucket.org/pypy/pypy/issues/1075/

Try the latest nightly.