test_g++_flags_speedup.cpp

#include <iostream>

using namespace std;

int main(){

	unsigned long long int last_number = 0;
	unsigned long long int current_number = 1;
	unsigned long long int currnum_buff = 0;

	for(int i=0; i<1000000000; i++){
		currnum_buff = current_number;
		current_number += last_number;
		last_number = currnum_buff;
	}

	cout << "The billionth fibonacci number is: " << current_number << endl;

	return 0;

}