From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <richard.guenther@gmail.com>
Received: from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com [IPv6:2a00:1450:4864:20::52e])
	by sourceware.org (Postfix) with ESMTPS id 604893858282
	for <gcc-patches@gcc.gnu.org>; Wed, 21 Sep 2022 09:36:46 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 604893858282
Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gmail.com
Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com
Received: by mail-ed1-x52e.google.com with SMTP id x21so680306edd.11
        for <gcc-patches@gcc.gnu.org>; Wed, 21 Sep 2022 02:36:46 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20210112;
        h=cc:to:subject:message-id:date:from:in-reply-to:references
         :mime-version:from:to:cc:subject:date;
        bh=CsNZckpN/79UrmFEAwQ03H9VgI/SX0jFoy6Df97UR8k=;
        b=jSzVPFd3U1sMXQl9wckXSD1UXuAzeTv8b/gY4ykaPPc2Y/DxDBfLYfYRzwgcEQUrzt
         1kakRf9h9qdy5ygSa4QFFhW9+9/lMH0RFhVouPw0UaYW5HHpUAh3kCATAPfoPMqCRCyd
         rqFNIFppLZ1Cpal2G+AFzSg7WWaExXTm1YZj/gCegUZEIYhIidQ7DmvQ5luvzInMMzk6
         s70DSYLnDHjpNY9xKA8YqYO7wwfHSi/N0DR83YCdb9Gl03qlytA7q0yEiT1a1IAMGIoU
         lTpN71AomOC878Y2EXnoLIL78aDfNvo5c5HxLz30MyhYP7L8ULfURgOYp4bMTz4IPOCj
         vArA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20210112;
        h=cc:to:subject:message-id:date:from:in-reply-to:references
         :mime-version:x-gm-message-state:from:to:cc:subject:date;
        bh=CsNZckpN/79UrmFEAwQ03H9VgI/SX0jFoy6Df97UR8k=;
        b=od4FCKhQLkj6KjxTHg3IV8OuR1+GRNXD/c+HL3YJbkhC6STPBk97mQ1GBPe+CPBWLo
         kVXyhRGlus9EcaIyEeIOlhI6zRV8FTRXpSyapR76bsaVMNaBfkjFjYL81UKnd21aQMtB
         P1luFQ/2ypmJCuo7kXMbm/qOjchQ0+amwWbkPBul3L6KsK4AI13LRm4pYeJ4RqSC8mpd
         ApY4mlPmS/fj1yQtKgWIKWSRy/WgrUyX2RPFKfFVb/f6L1UsmGwD8EEk48ua6TkknZgN
         xGUiM28E5+y3HFI7Xr4NLj05RLxNRJWqOEnRmVh+SEgbkRGfdlsPjVe/JdMyNAhFzWKd
         9tJQ==
X-Gm-Message-State: ACrzQf1mKwRpY+g7jHfHFBvSLnlapayC58sdcfyFq1lrc2XPIowkkaVy
	J0C4XL4yakVLtwh+DgBptSxjeDLzM5WDFeS0bsjc+ElB
X-Google-Smtp-Source: AMsMyM6YpPoGemI50P9Orbfd6OZb7lwYpXjBqe+ojMTZBolXxYyfqNfLBuxfR4FYHW2gCsDHbI3b7XtDGN9CjNnlqJ0=
X-Received: by 2002:a05:6402:1849:b0:453:ba03:9e41 with SMTP id
 v9-20020a056402184900b00453ba039e41mr16713224edy.202.1663753004083; Wed, 21
 Sep 2022 02:36:44 -0700 (PDT)
MIME-Version: 1.0
References: <20220920182223.2019637-1-aldyh@redhat.com> <CAFiYyc1DMo3Ge6VHbS0WioXS5owG-=hCwLJegtdUbFHvFsSh9w@mail.gmail.com>
 <CAGm3qMXzDhdPkipeuUHQDSj7xC41Rd0E3gzp9nS0embghv0fkw@mail.gmail.com>
In-Reply-To: <CAGm3qMXzDhdPkipeuUHQDSj7xC41Rd0E3gzp9nS0embghv0fkw@mail.gmail.com>
From: Richard Biener <richard.guenther@gmail.com>
Date: Wed, 21 Sep 2022 11:36:31 +0200
Message-ID: <CAFiYyc3mZwi7TW=F9Tu1ge-EJHFULtLq6M5MwNtY8DoTrFtWnA@mail.gmail.com>
Subject: Re: [COMMITTED] frange::maybe_isnan() should return FALSE for
 undefined ranges.
To: Aldy Hernandez <aldyh@redhat.com>
Cc: GCC patches <gcc-patches@gcc.gnu.org>
Content-Type: text/plain; charset="UTF-8"
X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org
List-Id: <gcc-patches.gcc.gnu.org>

On Wed, Sep 21, 2022 at 9:52 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> 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?

LGTM

>
> 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
> > >
> >