Adding in Javascript (NodeJS)

I'm trying to maximize my FLOPS in NodeJS, so I want to add using bitwise operations.

So:

var a = 6, b = 12;
a + b

Instead:

var add = function (a, b) {
    var carry, result, shiftedcarry;

    carry = a & b,
    result = a ^ b;

    while (carry !== 0) {
        shiftedcarry = carry << 1;
        carry = result & shiftedcarry;
        result ^= shiftedcarry;
    }

    return result;
}

add(a, b);

However, I found SO answers that said bitwise operations are slower in Javascript due to casting. Is there anyway to bypass this problem (like with a V8 extension or something)?

The reason I'm so focused on increasing my FLOPS is because I'm thinking of running a NodeJS experiment on a supercomputer.