#include <stdio.h>

struct {
	unsigned char flag;
	unsigned char val;
} l;

int main(int argc, char **argv)
{
	int i;

	for (i = 0; i < 100000000; i++) {
		l.val += 2;
		asm volatile("mfence" : : : "memory");
		if (l.flag)
			break;
		asm volatile("" : : : "memory");
	}

	return 0;
}