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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/98641] Feature request: implement pointer alignment builtins
Date: Wed, 13 Jan 2021 12:54:18 +0000	[thread overview]
Message-ID: <bug-98641-4-zFnWtg5uT9@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-98641-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98641

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Alex Richardson from comment #5)
> extern int i;
> _Static_assert(__builtin_is_aligned(__builtin_assume_aligned(&i, 16), 8),
> "");
> generates an "alignment of the base pointee object (4 bytes) is less than
> the asserted 16 byte" error when evaluating __builtin_assume_aligned().

in constant expression contexts perhaps, though I'd certainly not word it that
way, if it was evaluated at runtime, it could have been true if one is lucky
(or ensures it manually, e.g. by
int alignas(16) i;
at the variable definition).

  parent reply	other threads:[~2021-01-13 12:54 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 17:01 [Bug c++/98641] New: " ktkachov at gcc dot gnu.org
2021-01-12 17:02 ` [Bug c++/98641] " ktkachov at gcc dot gnu.org
2021-01-13  8:11 ` rguenth at gcc dot gnu.org
2021-01-13 10:07 ` redi at gcc dot gnu.org
2021-01-13 10:18 ` jakub at gcc dot gnu.org
2021-01-13 10:21 ` redi at gcc dot gnu.org
2021-01-13 12:44 ` Alexander.Richardson at cl dot cam.ac.uk
2021-01-13 12:53 ` Alexander.Richardson at cl dot cam.ac.uk
2021-01-13 12:54 ` jakub at gcc dot gnu.org [this message]
2021-01-13 14:31 ` Alexander.Richardson at cl dot cam.ac.uk

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