Date: Sat, 15 Jan 2011 00:02:34 -0800 From: Paul Eggert <eggert@cs.ucla.edu> Message-ID: <4D31549A.7060402@cs.ucla.edu> | Well, I'm afraid that's not true these days. With the latest GCC on x86, That's only because gcc is taking advantage of what the C standards people say is OK - it isn't because i386's can't, or doesn't, do "normal" 32 (or 64) bit 2's complement arithmetic (just as easily, or more easily than anything else). And that behaviour can be disabled (and IMO, should be ...) In practice the optimisation is useless - the code it makes go away wouldn't have been written in the first place if it wasn't important, so when it happens it just makes us programmers work harder to prevent the compiler from taking useless advantage. kre