Re: [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges.

[Richard Biener <richard.guenther@gmail.com>]

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
>