Sent from my iPhone
On Apr 23, 2010, at 10:25 AM, Heinz Riener <hrie...@student.tugraz.at>
wrote:
Dear all,
I'm using the native GCC version[1] of my GNU/Linux distribution. I
wonder whether GCC's optimization behavior is in the following case
correct. Consider the following two programs:
(1)
int test(int n) {
if (n > 0)
return 1;
return 0;
}
(2)
int test(int n) {
if (2*n > 0)
return 1;
return 0;
}
After compiling both with the flags '-c -O2 -pedantic -Wall', they
result in the same object file. I expected the object files to be
different. (The second program may overflow, the first program does
not.) Please, point me to the right direction.
Signed interger overflow is undefined. Use -fwrapv or -fno-strict-
overflow if you want gcc to behave as signed interger overflow being
defined.
[1]: gcc (GCC) 4.4.3 20100316 (prerelease)
Thanks,
Heinz
