http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51391
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-12-03 03:15:48 UTC --- inlineBug.h:16:8: warning: function ‘inlineBug::inlineBug()’ can never be inlined because it is suppressed using -fno-inline Without any -On (or -O or -Os), -fno-inline is the default. The warnings are correct based on what you are asking of the compiler.