Identifying bottlenecks in the program's operation

It is necessary to analyze the presented code fragment and identify potential performance issues present in it.

# include <iostream>
# include <cmath>

int main() {
    int sum{};
    for (;;) {
        int num = rand() % 42;
        if (num % 2 == 0) {
            sum += 2;
        } else {
            sum += 1;
        }
    }
}