opt.txt

class Main {
    void main() {
		Int a; 
        Int b;
        Int c;
        Int d;
        Int e;
        Int f;
        Gen g;

        g = new Gen();

        // dead code
        a = 4;
        b = a + c;
        d = 100 + a;

        // copy prop + constant folding
        a = 3; // -> ""
        b = a; // -> ""
        println(b); // -> println(3)
        println("\n");

        g.val = a;
        println(g.val + 4); // -> println(7);
        println("\n");

        g.gen();
        println(g.val); // no change
        println("\n");

        // copy prop + common sub expr
        a = g.gen();
        b = a; // -> ""
        c = b; // -> ""
        d = b + a; // -> a + a
        e = c + b + d; // -> d + d
        println(d + e);
        println("\n"); // print 6

        c = g.val + a;
        println(g.val + a); // -> println(c);
        println("\n");

        // dead code
        a = 4;
        b = 5 + 10; // 15
        c = b + a - 10; // 9
        if (c > a) {
            println("c > a\n"); // print this
        } else {
            println("c <= a\n");
        }
    }
}

class Gen {
    Int val;
    Int gen() { return 1; }
}