I apologize for stating that you had reported the issue. I copy/pasted from
your comment rather than the original report.
The issue was reported by Teodor Petrov
Kevin
"Manuel López-Ibáñez" wrote:
> > On 03/28/2016 01:56 PM, Florian Weimer wrote:
> >>> In Bugzilla PR # 70275, Manuel López-Ibáñez reports that even though
> >>> he provides the "-Werror=return-type" option, the compiler doesn't
> >>> flag the warning/error about a control reaching the end of a non-void
> >>> function, due to the presence of the "-w" option. He points out that
> >>> clang++ wtill flags the promoted warning even though warnings are
> >>> inhibited.
>
> I did not report the bug and did not mention anything of the above. I only
> commented on why GCC works like it works and how one can change the behaviour
> if so desired. I don't care one way or the other and I can see benefits for
> either behaviour.
>
> >> I think -w is ordered with respect to the other warning obtions, and
> >> -w inhibits previously requested warnings, and future -W flags may
> >> enable other warnings. With this in mind, I agree that the current
> >> GCC behavior is consistent and probably not a bug.
>
> The command-line order does not affect '-w' and there is no way to undo '-w'.
> It is a global boolean switch independent of anything else (including
> pragmas)
> that disables warnings just before they are re-classified (by pragmas or
> -Werror=) into something else. This means that if -Wfoobar is given in the
> command-line (or enabled by a pragma) and it requires an expensive analysis,
> this analysis is done even in the presence of -w, only the warning message is
> not emitted.
>
> One question to answer if the behaviour does change is what would be the
> effect
> of using '-w' on warning options enabled by #pragmas. Some people may still
> want a switch that simply disables all warnings no matter how they are
> enabled.
>
> Cheers,
>
> Manuel.