public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/108374] [12/13 Regression] unexpected -Wstringop-overflow when using std::atomic and std::shared_ptr
Date: Thu, 12 Jan 2023 10:00:06 +0000 [thread overview]
Message-ID: <bug-108374-4-D9y5xCQfjm@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108374-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108374
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #3)
> (In reply to Romain Geissler from comment #0)
> > std::weak_ptr<A> weakPointer(pointer);
> >
> > [[maybe_unused]] const unsigned int aAttr = weakPointer.lock()->_attr;
>
> If pointer == nullptr then weakPointer.lock() is also null, and so
> dereferencing it to access the attr member is undefined, and does indeed
> perform an atomic load at address 0.
>
> Instead of complaining about it, I would expect GCC to treat that undefined
> condition as unreachable and optimize it away.
Hmm, but then the program is bogus, no? And a diagnostic warranted.
At least if it is well-defined to have a nullptr == pointer.
So I'd be inclined to close as INVALID?
next prev parent reply other threads:[~2023-01-12 10:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-11 18:18 [Bug tree-optimization/108374] New: " romain.geissler at amadeus dot com
2023-01-11 18:19 ` [Bug tree-optimization/108374] " romain.geissler at amadeus dot com
2023-01-12 9:43 ` rguenth at gcc dot gnu.org
2023-01-12 9:57 ` redi at gcc dot gnu.org
2023-01-12 10:00 ` rguenth at gcc dot gnu.org [this message]
2023-01-12 10:10 ` redi at gcc dot gnu.org
2023-01-12 11:34 ` jakub at gcc dot gnu.org
2023-05-08 12:26 ` [Bug tree-optimization/108374] [12/13/14 " rguenth at gcc dot gnu.org
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-108374-4-D9y5xCQfjm@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).