我遇到了一个#define，他们在其中使用了__builtin_expect。Thedocumentation说:Built-inFunction:long__builtin_expect(longexp,longc)Youmayuse__builtin_expecttoprovidethecompilerwithbranchpredictioninformation.Ingeneral,youshouldprefertouseactualprofilefeedbackforthis(-fprofile-arcs),asprogrammersarenotoriouslybadatpre