int_py_mod_nonnegargs(): one arg is negative LLAssertFailure
Why am I getting this error ?pidigits.py runs fine outside of the pytest environment. Please see attached files
Hi, On 9 December 2016 at 02:00, Shubha Ramani via pypy-dev <pypy-dev@python.org> wrote:
Why am I getting this error ? pidigits.py runs fine outside of the pytest environment.
I'm getting: from rpython.jit.metainterp.test.support import LLJitMixin,X86JitMixin E ImportError: cannot import name X86JitMixin After hacking at that until the test runs (replacing it with LLJitMixin), then I see the problem. It's likely caused by integer overflow. Your f() function computes the digits of pi, but it's not valid RPython because integers overflow the size of C 'long'. An internal test then fails because although '(n*3 + a) % d' was supposedly proven to occur on known-nonnegative arguments, the value did overflow and is now negative. Copying the same algorithm in C with the type 'long' everywhere would be similarly undefined C code. Armin
Interesting. Thank You !
On Dec 9, 2016, at 12:45 AM, Armin Rigo <armin.rigo@gmail.com> wrote:
Hi,
On 9 December 2016 at 02:00, Shubha Ramani via pypy-dev <pypy-dev@python.org> wrote:
Why am I getting this error ? pidigits.py runs fine outside of the pytest environment.
I'm getting:
from rpython.jit.metainterp.test.support import LLJitMixin,X86JitMixin E ImportError: cannot import name X86JitMixin
After hacking at that until the test runs (replacing it with LLJitMixin), then I see the problem. It's likely caused by integer overflow. Your f() function computes the digits of pi, but it's not valid RPython because integers overflow the size of C 'long'. An internal test then fails because although '(n*3 + a) % d' was supposedly proven to occur on known-nonnegative arguments, the value did overflow and is now negative. Copying the same algorithm in C with the type 'long' everywhere would be similarly undefined C code.
Armin
participants (2)
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Armin Rigo -
Shubha Ramani