#include <stdio.h>

int main(int argc, char **argv) {
    int x = atoi(argv[1]);
    int y = atoi(argv[2]);

    for (int i = (x < y) * 2; i < 4 >> (x < y); ++i) {
        int res;

        switch (i) {
            case 0:
                if (__builtin_sadd_overflow(x, y, &res))
                    res = 0;
                break;
            case 1:
                if (__builtin_smul_overflow(x, y, &res))
                    res = 0;
                break;
            case 2:
                if (__builtin_ssub_overflow(x, y, &res))
                    res = 0;
                break;
            case 3:
                res = !(x
#ifdef UNNECESSARY_CODE
                        < y || x
#endif
                        % y) * (x / y);
                break;
        }

        printf("%dn", res);
    }
}

cc -Ofast -DUNNECESSARY_CODE -S -o a1.s a.c
cc -Ofast -S -o a2.s a.c