https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80716
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Can't reproduce with gcc version 6.3.1 20161221 (Red Hat 6.3.1-1) (GCC) nor current trunk. Perhaps the flags you've listed are incomplete? There is no -Wall nor -Wcomment nor -Wall -Werror nor -Werror=comment, so it certainly doesn't warn with the flags you've mentioned. It might be better if you attach the testcase, so that tabs vs. spaces are preserved.