[Bug c/94389] __attribute__((warn_unused_result)) will warn if the result is discarded as an optimisation

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94389

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
We end up during gimplification with:

get_flags ()
{
  int D.1939;

  text_mode ();
  D.1939 = 0;
  return D.1939;
}

which then leads to unused value. While:

int get_flags2(void) {
  return text_mode() ? O_TEXT : foo ();
}

is fine and no warning is reported.