https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67433
xuejuncao <xuejuncao at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|?: expresion returns |?: expression returns
|unexpected value when |unexpected value when
|condition is a bool |condition is a bool
|variable and it's value |variable which memory is
|above 1 |not true/false
--- Comment #1 from xuejuncao <xuejuncao at gmail dot com> ---
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
int main()
{
union u {
bool b;
char c;
} u;
memset((void *)&u, -1, sizeof(u));
bool b = (u.b ? 1 : 0);
int i = (u.b ? 1 : 0);
int j = (u.b ? 1 : 2);
printf("b = %d, i = %d, j = %d\n", b, i, j);
return 0;
}
without optimisation, the output is:
b = 1, i = 255, j = 1
with -O2, is:
b = 255, i = 255, j = 1
