void abort(void);
void exit(int);

void f(double *ty) {
    *ty = -1.0;
}

int main(void) {
    double foo[6];
    double tx = 0.0, ty, d;

    f(&ty);

    if (ty < 0)
        ty = -ty;
    d = (tx > ty) ? tx : ty;
    if (ty != d)
        abort();
    exit(0);
}
