This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
gcc 3.3 / i386 / -O2 question
- From: Andrew Haley <aph at redhat dot com>
- To: Beschorner Daniel <Daniel dot Beschorner at facton dot com>
- Cc: "'gcc at gcc dot gnu dot org'" <gcc at gcc dot gnu dot org>
- Date: Tue, 16 Nov 2004 12:14:26 +0000
- Subject: gcc 3.3 / i386 / -O2 question
- References: <BB1F4EFD574E9F409035BDA71C961250023915@exchange.i-bn>
Beschorner Daniel writes:
> Sorry, if this is the wrong list, but why differ the results in this simple
> example when compiled with -O and -O2 while GCC 2.95 is working fine?
> -fno-strict-aliasing makes no difference, but -fno-gcse-(sm) helps.
>
> outputs are
> -O: -1343238496
> -O2: -1474736480
>
> Thanks Daniel
>
>
> int A,B,C;
> int i;
> int Q[1];
> int H(int X, int Y)
> {
> return X*Y;
> }
> int main()
> {
> A=B=C=100000;
> A+=H(B,C);
Integer overflow. All bets are off.
Andrew.