http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54848
Bug #: 54848
Summary: -ftrapv doesn't work when assigning to an integer with
smaller size
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: [email protected]
ReportedBy: [email protected]
Host: i686-pc-linux-gnu
Target: i686-pc-linux-gnu
Build: i686-pc-linux-gnu
When adding, subtracting or multiplying two integers and assigning the result
to a variable with smaller size, trap on overflow doesn't happen.
See for example this program:
#include <stdio.h>
int main(void)
{
int a = 0x70000000;
int b = 0x50000000;
short c = a + b;
printf("%x\n", c);
return 0;
}
We compile the program without optimization and with -ftrapv, so that it should
crash because of integer overflow. But the program doesn't crash. If we replace
"short" with "int", an overflow crash happens correctly.
