Problem related to segmented sieve code as given in video

#1

If start is less than m will it not give a error…shouldn’t we check if start is less than m first

#2 
    for (auto x : primes)
        {
            // end point to stop iterating the primes
            if (x * x > n)
                break;
            int start = (m / x) * x;

            // if the number is the prime itself start from next multiple
            if (x >= m and x <= n)
            {
                start = x * 2;
            }
            for (ll i = start; i <= n; i += x)
            {
                segment[i - m] = 1;
            }
        }

start will not be less than m at any point in the code
start = (m/x)*x
will give value give value greater than equal to m