The reason the flags were uninitialized was because they were unused,
similarly for m_type.  But you're right, it is icky and prone to bugs.
I just thought it was cheap to set_undefined by just flipping
m_kind=VR_UNDEFINED, but it smells like premature optimization.

How about this?

Aldy

On Wed, Sep 21, 2022 at 9:39 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Tue, Sep 20, 2022 at 8:23 PM Aldy Hernandez via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > Undefined ranges have undefined NAN bits.  We can't depend on them,
> > as they may contain garbage.
>
> Ick ;)  Can you add a comment at least?
>
> > This patch returns false from
> > maybe_isnan() for undefined ranges (the empty set).
> >
> > gcc/ChangeLog:
> >
> >         * value-range.h (frange::maybe_isnan): Return false for
> >         undefined ranges.
> > ---
> >  gcc/value-range.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/gcc/value-range.h b/gcc/value-range.h
> > index 7d5584a9294..325ed08f290 100644
> > --- a/gcc/value-range.h
> > +++ b/gcc/value-range.h
> > @@ -1210,6 +1210,8 @@ frange::known_isinf () const
> >  inline bool
> >  frange::maybe_isnan () const
> >  {
> > +  if (undefined_p ())
> > +    return false;
> >    return m_pos_nan || m_neg_nan;
> >  }
> >
> > --
> > 2.37.1
> >
>