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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/109442] Dead local copy of std::vector not removed from function
Date: Tue, 11 Apr 2023 13:38:25 +0000	[thread overview]
Message-ID: <bug-109442-4-lq9EQQK1oI@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109442-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109442

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Ah, maybe the problem is that the library code manually elides destroying the
elements, precisely because it's a no-op. So we don't actually destroy the
elements, which means the compiler might think they're still initialized and so
could be inspected.

If the library explicitly does vec[i].~T() for every i then would that help?
The compiler would know there are no valid elements in the storage, and so
nothing operator delete could inspect.

We could continue to elide destroying the elements when !defined __OPTIMIZE__
so that we don't run a loop that does nothing, but with optimization enabled
rely on the compiler to remove that loop.

  parent reply	other threads:[~2023-04-11 13:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-06 19:00 [Bug tree-optimization/109442] New: " hiraditya at msn dot com
2023-04-11 13:28 ` [Bug tree-optimization/109442] " rguenth at gcc dot gnu.org
2023-04-11 13:33 ` redi at gcc dot gnu.org
2023-04-11 13:38 ` redi at gcc dot gnu.org [this message]
2023-04-12  7:40 ` [Bug libstdc++/109442] " rguenth at gcc dot gnu.org
2023-04-12  9:29 ` redi at gcc dot gnu.org
2023-04-12  9:45 ` rguenth at gcc dot gnu.org
2023-04-12 10:01 ` redi at gcc dot gnu.org
2023-04-12 10:13 ` redi at gcc dot gnu.org
2023-04-12 10:22 ` rguenth at gcc dot gnu.org
2023-04-12 10:29 ` redi at gcc dot gnu.org
2023-04-12 10:35 ` redi at gcc dot gnu.org
2023-04-12 11:52 ` rguenther at suse dot de
2023-04-12 11:55 ` redi at gcc dot gnu.org
2023-04-16 18:38 ` richard-gccbugzilla at metafoo dot co.uk
2023-04-17  6:49 ` rguenth at gcc dot gnu.org
2023-04-18  2:15 ` richard-gccbugzilla at metafoo dot co.uk
2023-06-15 18:38 ` hiraditya at msn dot com
2024-05-11  0:07 ` xry111 at gcc dot gnu.org
2024-05-11 16:05 ` hubicka at gcc dot gnu.org
2024-05-14 13:47   ` Jan Hubicka
2024-05-11 16:44 ` redi at gcc dot gnu.org
2024-05-14 13:47 ` hubicka at ucw dot cz

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