From: Eli Zaretskii <eliz@gnu.org>
To: Paul Eggert <eggert@cs.ucla.edu>
Cc: rcopley@gmail.com, angelo.g0@libero.it, emacs-devel@gnu.org
Subject: Re: Suspicious warning in W64 build
Date: Thu, 07 Sep 2017 23:20:51 +0300 [thread overview]
Message-ID: <83bmmmz2e4.fsf@gnu.org> (raw)
In-Reply-To: <102a4c21-c275-c73e-ec53-0d85975dc968@cs.ucla.edu> (message from Paul Eggert on Thu, 7 Sep 2017 12:26:06 -0700)
> Cc: angelo.g0@libero.it, emacs-devel@gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Thu, 7 Sep 2017 12:26:06 -0700
>
> > Yes, I know. I just don't understand why GCC things that
> >
> > nglyphs * sizeof (WORD) * 2
> >
> > can have a value in this range. The type of nglyphs is 'int', and
> > sizeof(WORD) gives 2. So the range should be between 0 (or 4) and 4
> > times INT_MAX, which is nowhere near the values GCC displays.
> >
>
> If nglyphs is negative the first multiplication is done using unsigned
> arithmetic, which could result in huge results. Presumably GCC does not know
> that nglyphs must be nonnegative. Try putting an 'eassume (0 <= nglyphs);'
> before the line in question. That is, if you're sure that nglyphs is
> nonnegative: if you're not, GCC has found a real bug here.
nglyphs is always positive, it comes from nchars of a glyph_string, or
similar.
Angelo and Richard, can you please try that eassume and see if it
shuts up the warning?
next prev parent reply other threads:[~2017-09-07 20:20 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 13:38 Suspicious warning in W64 build Angelo Graziosi
2017-09-05 14:04 ` Richard Copley
2017-09-07 15:16 ` Eli Zaretskii
2017-09-07 15:42 ` Angelo Graziosi
2017-09-07 17:52 ` Richard Copley
2017-09-07 17:58 ` Richard Copley
2017-09-07 19:00 ` Angelo Graziosi
2017-09-07 19:21 ` Richard Copley
2017-09-09 4:58 ` Herring, Davis
2017-09-09 9:55 ` Richard Copley
2017-09-09 10:20 ` Eli Zaretskii
2017-09-09 11:24 ` Angelo Graziosi
2017-09-09 13:25 ` Eli Zaretskii
2017-09-09 11:16 ` Angelo Graziosi
2017-09-07 18:58 ` Eli Zaretskii
2017-09-07 19:26 ` Paul Eggert
2017-09-07 19:50 ` Richard Copley
2017-09-07 20:02 ` Richard Copley
2017-09-08 6:49 ` Eli Zaretskii
2017-09-08 8:02 ` Eli Zaretskii
2017-09-08 19:31 ` Richard Copley
2017-09-08 20:17 ` Eli Zaretskii
2017-09-08 21:08 ` Richard Copley
2017-09-08 21:37 ` Richard Copley
2017-09-09 7:37 ` Eli Zaretskii
2017-09-08 22:20 ` Richard Copley
2017-09-09 7:33 ` Eli Zaretskii
2017-09-09 9:36 ` Richard Copley
2017-09-09 10:42 ` Eli Zaretskii
2017-09-09 10:52 ` Eli Zaretskii
2017-09-09 11:17 ` Richard Copley
2017-09-09 16:07 ` Eli Zaretskii
2017-09-10 1:01 ` Richard Copley
2017-09-10 14:40 ` Eli Zaretskii
2017-09-10 19:14 ` Richard Copley
2017-09-10 19:38 ` Angelo Graziosi
2017-09-11 16:17 ` Eli Zaretskii
2017-09-11 22:21 ` Angelo Graziosi
2017-09-11 16:39 ` Óscar Fuentes
2017-09-11 17:20 ` Eli Zaretskii
2017-09-12 17:49 ` Eli Zaretskii
2017-09-12 18:01 ` Fabrice Popineau
2017-09-12 18:37 ` Richard Copley
2017-09-12 18:59 ` Eli Zaretskii
2017-09-12 19:14 ` Richard Copley
2017-09-12 18:38 ` Eli Zaretskii
2017-09-14 17:47 ` Eli Zaretskii
2017-09-14 19:34 ` Richard Copley
2017-09-15 8:54 ` Eli Zaretskii
2017-09-15 23:05 ` Richard Copley
2017-09-16 6:40 ` Eli Zaretskii
2017-09-16 8:19 ` Richard Copley
2017-09-16 8:34 ` Richard Copley
2017-09-16 8:54 ` Eli Zaretskii
2017-09-16 9:07 ` Richard Copley
2017-09-16 11:54 ` Fabrice Popineau
2017-09-16 8:52 ` Eli Zaretskii
2017-09-15 8:59 ` Eli Zaretskii
2017-09-15 14:43 ` Eli Zaretskii
2017-09-17 6:42 ` Paul Eggert
2017-09-17 7:14 ` Richard Copley
2017-09-17 14:31 ` Eli Zaretskii
2017-09-17 6:40 ` Paul Eggert
2017-09-17 14:29 ` Eli Zaretskii
2017-09-17 16:39 ` Fabrice Popineau
2017-09-17 16:52 ` Eli Zaretskii
2017-09-18 0:26 ` Paul Eggert
2017-09-18 11:47 ` Fabrice Popineau
2017-09-18 14:46 ` Eli Zaretskii
2017-09-18 0:01 ` Richard Stallman
2017-09-14 19:36 ` Fabrice Popineau
2017-09-14 21:17 ` Andy Moreton
2017-09-15 6:55 ` Fabrice Popineau
2017-09-15 9:12 ` Eli Zaretskii
2017-09-15 15:33 ` Fabrice Popineau
2017-09-15 15:45 ` Eli Zaretskii
2017-09-15 18:15 ` Fabrice Popineau
2017-09-15 19:00 ` Eli Zaretskii
2017-09-15 21:02 ` Fabrice Popineau
2017-09-16 7:45 ` Eli Zaretskii
2017-09-17 7:01 ` Paul Eggert
2017-09-17 14:31 ` Eli Zaretskii
2017-09-17 14:52 ` Philipp Stephani
2017-09-17 22:34 ` Paul Eggert
2017-09-17 17:07 ` Paul Eggert
2017-09-17 17:14 ` Eli Zaretskii
2017-09-17 18:53 ` Paul Eggert
2017-09-17 19:30 ` Eli Zaretskii
2017-09-17 20:34 ` Paul Eggert
2017-09-18 2:30 ` Eli Zaretskii
2017-09-18 4:52 ` Paul Eggert
2017-09-18 14:41 ` Eli Zaretskii
2017-09-18 17:35 ` Paul Eggert
2017-09-18 17:58 ` Andy Moreton
2017-09-19 9:05 ` Paul Eggert
2017-09-18 18:01 ` Eli Zaretskii
2017-09-17 20:45 ` Paul Eggert
2017-09-16 13:17 ` Andy Moreton
2017-09-16 13:46 ` Eli Zaretskii
2017-09-16 18:57 ` Richard Copley
2017-09-16 19:21 ` Eli Zaretskii
2017-09-15 9:03 ` Eli Zaretskii
2017-09-09 8:49 ` Angelo Graziosi
2017-09-09 10:37 ` Eli Zaretskii
2017-09-09 11:32 ` Angelo Graziosi
2017-09-09 13:28 ` Eli Zaretskii
2017-09-09 13:33 ` Fabrice Popineau
2017-09-09 14:55 ` Angelo Graziosi
2017-09-09 16:37 ` Eli Zaretskii
2017-09-09 18:38 ` Angelo Graziosi
2017-09-09 18:59 ` Eli Zaretskii
2017-09-09 21:29 ` Angelo Graziosi
2017-09-10 14:56 ` Eli Zaretskii
2017-09-10 15:45 ` Angelo Graziosi
2017-09-10 16:02 ` Eli Zaretskii
2017-09-10 18:45 ` Angelo Graziosi
2017-09-10 19:43 ` Eli Zaretskii
2017-09-09 15:40 ` Angelo Graziosi
2017-09-09 16:40 ` Eli Zaretskii
2017-09-09 18:33 ` Fabrice Popineau
2017-09-07 20:20 ` Eli Zaretskii [this message]
2017-09-07 21:59 ` Angelo Graziosi
2017-09-08 8:01 ` Eli Zaretskii
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