public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "redbeard0531 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/105534] -Wmaybe-uninitialized cases shouldn't suppress -Wuninitialized warnings
Date: Mon, 09 May 2022 13:51:28 +0000 [thread overview]
Message-ID: <bug-105534-4-9JLW8mvSoS@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-105534-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105534
--- Comment #4 from Mathias Stearn <redbeard0531 at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Note there's
>
> _2 = value_1(D) * x_2;
>
> where _2 might be effectively uninitialized iff x_2 is not zero. When x_2
> is zero then _2 has a well-defined value.
Not according to the C++ standard. http://eel.is/c++draft/basic.indet seems
pretty clear that unless x_2 is std::byte (which doesn't support
multiplication) or an "unsigned ordinary character type", then that is UB.
FWIW I still think I'd expect the warning on "unsigned char x, y; y = x * 0;",
but I would definitiely expect the warning for int.
prev parent reply other threads:[~2022-05-09 13:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 12:22 [Bug c++/105534] New: -Wmaybe-uninitialized " redbeard0531 at gmail dot com
2022-05-09 13:05 ` [Bug c++/105534] -Wmaybe-uninitialized cases " rguenth at gcc dot gnu.org
2022-05-09 13:21 ` rguenth at gcc dot gnu.org
2022-05-09 13:41 ` redbeard0531 at gmail dot com
2022-05-09 13:51 ` redbeard0531 at gmail dot com [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=bug-105534-4-9JLW8mvSoS@http.gcc.gnu.org/bugzilla/ \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@gcc.gnu.org \
/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 read-only IMAP folder(s) and NNTP newsgroup(s).