[Bug c/92479] missing warnings for unreachable codes with break (i.e. revive the subset of -Wunreachable-code that fits under clang's -Wunreachable-code-break)

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92479

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Interestingly clang doesn't warn for

int main()
{
  for(int i = 1;; i++){
    if(0)
      {
        ++i;
        break;
      }
  }
}

which looks quite stupid (an empty stmt is OK though).  In fact diagnosing
that specifically a 'break' is not reachable and controlling that with its
own option looks bogus.

I'm going to re-interpret -Wunreachable-code-{return,break} to mean to
diagnose unreachable code _after_ a return stmt or a break stmt.  It really
looks like clang went out with a hammer, assigning a different option to
each diagnostic invocation with a different text ...