GCC 优化选项 -O1 -O2 -O3 -Os 优先级,-fomit-frame-pointer
少优化->多优化:O0-->>O1-->>O2-->>O3-O0表示没有优化,-O1为缺省值,-O3优化级别最高英文解析:`-O'`-O1'Optimize.Optimizingcompilationtakessomewhatmoretime,andalotmorememoryforalargefunction.With`-O',thecompilertriestoreducecodesizean