log

vmware@vmware-virtual-machine:~/test$ gcc inc.cc inc-sub.cc -o inc -O0
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m3.121s
user	0m3.118s
sys	0m0.000s
vmware@vmware-virtual-machine:~/test$ gcc inc.cc inc-sub.cc -o inc -O3
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m2.427s
user	0m2.416s
sys	0m0.008s
vmware@vmware-virtual-machine:~/test$ clang inc.cc inc-sub.cc -o inc -O0
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m3.248s
user	0m3.240s
sys	0m0.004s
vmware@vmware-virtual-machine:~/test$ clang inc.cc inc-sub.cc -o inc -O3
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m2.359s
user	0m2.353s
sys	0m0.004s
vmware@vmware-virtual-machine:~/test$ cat inc.cc 
bool foo(int, int*);

int main() {
  int i = 0;
  while (foo(++i, &i));
  return 0;
}
vmware@vmware-virtual-machine:~/test$ sed -i inc.cc -e 's/++i/i++/'
vmware@vmware-virtual-machine:~/test$ cat inc.cc 
bool foo(int, int*);

int main() {
  int i = 0;
  while (foo(i++, &i));
  return 0;
}
vmware@vmware-virtual-machine:~/test$ gcc inc.cc inc-sub.cc -o inc -O0
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m3.335s
user	0m3.327s
sys	0m0.004s
vmware@vmware-virtual-machine:~/test$ gcc inc.cc inc-sub.cc -o inc -O3
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m2.331s
user	0m2.324s
sys	0m0.004s
vmware@vmware-virtual-machine:~/test$ clang inc.cc inc-sub.cc -o inc -O0
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m3.114s
user	0m3.107s
sys	0m0.004s
vmware@vmware-virtual-machine:~/test$ clang inc.cc inc-sub.cc -o inc -O3
vmware@vmware-virtual-machine:~/test$ time ./inc 

real	0m2.297s
user	0m2.294s
sys	0m0.000s