// S : tags   sym c  $TAGS
// S : expect --result valid
// S : cc     -o test.bc  $CC_OPT $file
// S : verify --symbolic --solver $solver --sequential $V_OPT test.bc

// N : V              : CC_OPT           : V_OPT : TAGS : RESULT
// V : small.10       : -DNUM=10         :       :      : valid
// V : big.1073741823 : -DNUM=1073741823 :       : big  : valid
// V : small.1000     : -DNUM=1000       :       : big  : valid
// V : small.100      : -DNUM=100        :       : big  : valid

extern void __VERIFIER_error() __attribute__ ((__noreturn__));

/*
 * Recursive implementation integer addition.
 *
 * Author: Matthias Heizmann
 * Date: 2013-07-13
 *
 */

extern int __VERIFIER_nondet_int(void);

int addition(int m, int n) {
    if (n == 0) {
        return m;
    }
    else if (n > 0) {
        return addition(m+1, n-1);
    }
    else {
        return addition(m-1, n+1);
    }
}

int main() {
    int m = __VERIFIER_nondet_int();
    if (m < 0 || m > NUM) {
        // additional branch to avoid undefined behavior
        // (because of signed integer overflow)
        return 0;
    }
    int n = __VERIFIER_nondet_int();
    if (n < 0 || n > NUM) {
        // additional branch to avoid undefined behavior
        // (because of signed integer overflow)
        return 0;
    }
    int result = addition(m,n);
    if (result == m + n) {
        return 0;
    } else {
        ERROR: __VERIFIER_error();
    }
}