New issue 2704: Undefined behavior in RPython via the C backend https://bitbucket.org/pypy/pypy/issues/2704/undefined-behavior-in-rpython-via-the-c
Carl Friedrich Bolz-Tereick: We did not completely decide so far whether int-addition (and other ops) in RPython must behave a) by wrapping around or b) by having undefined behavior on overflow. Right now, the C backend and parts of the JIT implements b). However, we definitely have code where we use int operations that overflow and we expect a), most notably a lot of hash computations (eg ``W_TupleObject._descr_hash_*``). This has the potential (maybe unlikely though?) of causing miscompilation of PyPy at any point in the future when GCC (or the JIT) gets smarter about reasoning about ints. _______________________________________________ pypy-issue mailing list pypy-issue@python.org https://mail.python.org/mailman/listinfo/pypy-issue
