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From: "wilco at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/110773] [Aarch64] crash (SIGBUS) due to atomic
 instructions on under-aligned memory
Date: Thu, 04 Apr 2024 17:54:11 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110773

--- Comment #8 from Wilco <wilco at gcc dot gnu.org> ---
(In reply to Sainan from comment #7)
> (In reply to Wilco from comment #6)
> > That does not make any sense. The only thing I think might happen is th=
at
> > your structure is not correctly aligned (for example by using a custom
> > memory allocator). Can you check the address of count when it fails? (s=
hould
> > be in the crash logs, or you can see it in gdb or just printf it).
>=20
> I feel silly for not thinking of printing the address, but now that I did=
, I
> see the final hexit is '9' and so it just so happens this CPU can't deal
> with that...

So it's unaligned then, and that's not supported. And you're lucky your
specific alignment happens to work on v8.4 cores - it would fail for other
offsets.=