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