[Python-Dev] Integer Overflow

[Tim Peters]

Glad you found it!  Note that the result of shifting a 32-bit integer *by*
32 isn't defined in C (gotta love it ...), so "no-op" was lucky.

> -----Original Message-----
> From: Martin v. Loewis [mailto:martin@loewis.home.cs.tu-berlin.de]
> Sent: Thursday, September 14, 2000 3:32 AM
> To: tim_one@email.msn.com
> Cc: python-dev@python.org
> Subject: Re: [Python-Dev] Integer Overflow
>
>
> > Works for me (Windows).  Local corruption?  Compiler optimization error?
> > Config screwup?
>
> Config screwup. I simultaneously try glibc betas, and 2.1.93 manages
> to define LONG_BIT as 64 (due to testing whether INT_MAX is 2147483647
> at a time when INT_MAX is not yet defined). Shifting by LONG_BIT/2 is
> then a no-op, so ah=a, bh=b in int_mul. gcc did warn about this, but I
> ignored/forgot about the warning.
>
> I reported that to the glibc people, and worked-around it locally.
>
> Sorry for the confusion,
>
> Martin