Find time complexity of a code that runs three loops

I have this piece of code and I would like to find its time complexity. I am preparing for interviews and I think this one is a bit tough.

int foo (int n) 
{
    int sum = 0;
    int k, i, j;
    int t = 2;

    for (i=n/2; i>0; i/=2)
    {
        for(j=0; j<i; j++) 
        { 
            for(k=0; k<log2(t-1); k++) 
            {
                sum += bar(sum);
                // bar time-complexity for all inputs is O(1)
            }
        }
        t = pow(2, i);
    }
}

I don't know why but I am unable to bound this expression and find a complexity.

Any help on how to resolve this ?