[Bug c++/12668] Strange warnings with -O1 -Wunreachable-code in 3.3.1,3.3.2,3.4

["rmerkert at alphatech dot com" <gcc-bugzilla at gcc dot gnu dot org>]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12668



------- Additional Comments From rmerkert at alphatech dot com  2003-10-18 13:24 -------
I still think that the warning is not very helpful. Consider this program instead:
cat > test.c <<EOF
inline void foo (int x)
{
   if (x!=0)
     x = x + 1;
}

int main ()
{
  foo(-1);
  foo(0);
  foo(1);
  foo(2);

  return 0;
}

EOF

gcc -O1 test.c -Wunreachable-code

This will give exactly the same warning as before:

main.c: In function `main':
main.c:4: warning: will never be executed

The warning is completely useless. The warning is not even pointing me to the
root cause which is the call to foo(0). 
I think that the warning should be something like this:
main.c: In function `main':
main.c:10: warning: call to foo has been optimized away