C2 is currently not able to optimize checks like the following:

    public static void test1(boolean inc) {
        int i = 42;
        if (inc) {
            i += 100;
        }
        // i: 42..142
        if (i != 42) {
            // i: 43..142
            if (i <= 42) {
               throw new RuntimeException("Should not reach here");
            }
        }
    }

Since i can never be <= 42 in the inner branch, all code could be removed.