From: Arnd Bergmann <arnd@arndb.de>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] bitops: avoid clang shift-count-overflow warnings
Date: Tue, 5 May 2020 17:44:12 +0200 [thread overview]
Message-ID: <CAK8P3a3khvHTf2qALrGQoh5iunHkWOqPXSt1A1_7sO7m2JxMVg@mail.gmail.com> (raw)
In-Reply-To: <CAKwvOd=6jdRedjhcuQ0Bsr5hJ9djp8xLpLmT-bC9Wd-1GYK1fw@mail.gmail.com>
On Tue, May 5, 2020 at 5:36 PM 'Nick Desaulniers' via Clang Built
Linux <clang-built-linux@googlegroups.com> wrote:
> On Tue, May 5, 2020 at 8:33 AM Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > I'm not sure if there is anything to be done about it in clang, since it
> > always does syntactic analysis before dead-code elimination by design.
>
> That's pretty much it. We had a patch to Clang to use delayed
> diagnostics to delay emitting the warning in case the AST node was
> dropped, but it wasn't accepted in code review.
>
> >
> > It is a bit odd though that it only prints the warning sometimes, but
>
> Sometimes?
Well, the file is included everywhere in the kernel, but we normally
don't get the
warning at all. However, I sometimes make incorrect changes to one file that
cause some other warning, and the result is an stream of warnings about
things like this one that are normally hidden. The shift count warning is the
one that shows up the most. I should try to come up with a better way to
reproduce it.
Arnd
prev parent reply other threads:[~2020-05-05 15:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 13:54 [PATCH] bitops: avoid clang shift-count-overflow warnings Arnd Bergmann
2020-05-05 14:01 ` Christian Brauner
2020-05-05 14:08 ` Andy Shevchenko
2020-05-05 15:32 ` Arnd Bergmann
2020-05-05 15:36 ` Nick Desaulniers
2020-05-05 15:44 ` Arnd Bergmann [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAK8P3a3khvHTf2qALrGQoh5iunHkWOqPXSt1A1_7sO7m2JxMVg@mail.gmail.com \
--to=arnd@arndb.de \
--cc=akpm@linux-foundation.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=andy.shevchenko@gmail.com \
--cc=christian.brauner@ubuntu.com \
--cc=clang-built-linux@googlegroups.com \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=ndesaulniers@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).