https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78809
--- Comment #6 from Qing Zhao <qing.zhao at oracle dot com> --- (A correction to comment 4: when adding #include <string.h>, the call to strcmp(s, "a") was inlined by glibc in the header with the latest upstream GCC ) with attached testing case, on GCC farm machine gcc116, I got the following run-time performance data: qinzhao@gcc116:~/Bugs/78809/const_cmp$ sh t_p /home/qinzhao/Install/latest/bin/gcc -O2 t_p_1.c t_p.c -DINLINED inlined version 41.67user 0.00system 0:41.67elapsed 99%CPU (0avgtext+0avgdata 360maxresident)k 0inputs+0outputs (0major+135minor)pagefaults 0swaps /home/qinzhao/Install/latest/bin/gcc -O2 t_p_1.c t_p.c non-inlined version 20.84user 0.00system 0:20.83elapsed 100%CPU (0avgtext+0avgdata 360maxresident)k 0inputs+0outputs (0major+135minor)pagefaults 0swaps >From the data, we can see the inlined version of strcmp (by glibc) is much slower than the direct call to strcmp. (this is for size 2) I am using GCC farm machine gcc116: qinzhao@gcc116:~/Bugs/78809/const_cmp$ uname -a Linux gcc116 3.13.0-92-generic #139-Ubuntu SMP Tue Jun 28 20:45:34 UTC 2016 aarch64 aarch64 aarch64 GNU/Linux
