unlikely
#define unlikely(expr) expect((expr) != 0, 0)
#define unlikely(x) __predict_false(x)
#define unlikely(x) __predict_false(x)
#define unlikely(x) __builtin_expect((long)!!(x), 0L)
#define unlikely(expr) expect((expr) != 0, 0)
#define unlikely(expr) expect((expr) != 0, 0)