Re: Compiling CVS HEAD with clang under OSX

Martijn van Oosterhout <kleptog@svana.org>

From: Martijn van Oosterhout <kleptog@svana.org>
To: Greg Stark <gsstark@mit.edu>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Neil Conway <neil.conway@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2010-08-03T20:42:04Z
Lists: pgsql-hackers
On Mon, Aug 02, 2010 at 05:34:57PM +0100, Greg Stark wrote:
> Tom: Because that code is much more complex and prone to errors
> especially when you start getting into multiplication and other
> operations and it's also much slower than the code which allows
> overflow to happen and then checks that the result makes sense.

> I'm not entirely sure I agree. At least I haven't actually gone
> through all the arithmetic operations and I'm not sure how much more
> complex they get. If they were all at that level of complexity I think
> I would say we should go ahead and bite the performance bullet and do
> it the ultra-safe way.

FWIW, here's a site with some gcc magic which will allow you to detect
overflows during addition. Ofcourse, the fact that it's gcc specific
makes it a lot less useful.

http://www.fefe.de/intof.html

Have a nice day,
-- 
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patriotism is when love of your own people comes first; nationalism,
> when hate for people other than your own comes first. 
>                                       - Charles de Gaulle