https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #29 from Chung-Kil Hur <gil.hur at sf dot snu.ac.kr> ---
Dear Richard,
This time, I think I constructed a real bug.
Please have a look and correct me if I am wrong.
=====================
#include <stdio.h>
int main() {
int x = 0;
uintptr_t xp = (uintptr_t) &x;
uintptr_t i;
for (i = 0; i < xp; i++) { }
*(int*)xp = 15;
printf("%d\n", x);
}
=====================
This program prints "15" and I do not think this raises UB.
Now I add an if-statement to the program.
=====================
#include <stdio.h>
int main() {
int x = 0;
uintptr_t xp = (uintptr_t) &x;
uintptr_t i;
for (i = 0; i < xp; i++) { }
/*** begin ***/
if (xp != i) {
printf("hello\n");
xp = i;
}
/*** end ***/
*(int*)xp = 15;
printf("%d\n", x);
}
=====================
This program just prints "0".
Since "hello" is not printed, the if-statement is not executed.
However, it prints a different result than before, which I think is a bug.
