https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107912
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Keywords|diagnostic |
Last reconfirmed| |2022-11-29
Summary|UBsan at -O0 missed a |shorterning causes a
|signed integer overflow |missing signed integer
| |overflow
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Another example where optimization level does not matter:
```
unsigned short a;
int b;
int main() {
int c = b = -2147483648;
unsigned short t = 0;
a = t - b;
__builtin_printf("%d\n", a);
}
```
I thought we had there was a bug report about this but I can't find it right
now.
Anyways confirmed. The only reason why the original example works at -O1 and
above is because (c && c == 0) is figured out to be false (0) and then 0-b is
translated into -b and the shorterning does not happen.
