main.cpp

#include <iostream>
#include <functional>
#include <limits>
#include <cstdint>
#include <random>
#include <chrono>

void inc_uint64_1( std::uint64_t &val ) noexcept
{
	if( ++val == 0ull )
	{
		val = std::numeric_limits< std::uint64_t >::max();
	}
}
void inc_uint64_2( std::uint64_t &val ) noexcept
{
	++val;
	val |= -(val == 0ull);
}

int main()
{
	std::random_device rnd;
	std::uint64_t const v = std::uniform_int_distribution< std::uint64_t >( 0xFFFFFFFFF0000000ull, 0xFFFFFFFFFFFFFFFFull )( rnd );
	std::uint64_t const loopnum = std::uniform_int_distribution< std::uint64_t >( 0x10000000ull, 0xFFFFFFFFull )( rnd );
	{
		std::uint64_t val = v;
		std::cout << val << std::endl;
		auto start = std::chrono::high_resolution_clock::now();
		for( std::uint64_t i = 0; i < loopnum; ++i )
		{
			inc_uint64_1( val );
		}
		auto end = std::chrono::high_resolution_clock::now();
		std::cout << val << std::endl;
		std::cout << std::chrono::duration_cast< std::chrono::duration< double > >( end - start ).count() << std::endl;
	}
	{
		std::uint64_t val = v;
		std::cout << val << std::endl;
		auto start = std::chrono::high_resolution_clock::now();
		for( std::uint64_t i = 0; i < loopnum; ++i )
		{
			inc_uint64_2( val );
		}
		auto end = std::chrono::high_resolution_clock::now();
		std::cout << val << std::endl;
		std::cout << std::chrono::duration_cast< std::chrono::duration< double > >( end - start ).count() << std::endl;
	}
}