likely应用

#include <stdlib.h>
#include <iostream>
using namespace std;
#define likely(x) __builtin_expect(!!(x), 1) 
#define unlikely(x) __builtin_expect(!!(x), 0)

int main() {
    int x;
    cin >> x;
    if (unlikely(x) >= 100000) {
        cout << x << " is too big." << endl;
    }

    return 0;
}

 objdump -S Test