Test of pow versus multiplication performance

pow_vs_mul.cpp

#include <chrono>
#include <cmath>
#include <iostream>

template<typename F>
auto timeit(F f) {
    int const ITERS = 1'000;
    using namespace std::chrono;
    auto b = system_clock::now();
    volatile int dummy;
    for (int i = 0; i < ITERS; ++i)
        dummy = f();
    (void)dummy;
    auto e = system_clock::now();
    return duration_cast<nanoseconds>(e - b).count();
}

int const TESTS = 1'000'000;

double trivial() {
    return 0;
}

double total_pow() {
    double total = 0;
    for (int i = 0; i < TESTS; ++i)
        total += std::pow(i, 2);
    return total;
}

double total_mul() {
    double total = 0;
    for (int i = 0; i < TESTS; ++i)
        total += i*i;
    return total;
}

int main() {
    std::cout << "trivial: " << timeit(trivial) << '\n';
    std::cout << "pow: " << timeit(total_pow) << '\n';
    std::cout << "mul: " << timeit(total_mul) << '\n';
}