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From: "sainan+gcc.bugzilla at calamity dot gg" <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 10:44:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110773

Sainan <sainan+gcc.bugzilla at calamity dot gg> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sainan+gcc.bugzilla@calamit
                   |                            |y.gg

--- Comment #3 from Sainan <sainan+gcc.bugzilla at calamity dot gg> ---
I seem to be having a related issue, although in my case the struct looks l=
ike
this:

template <typename T>
struct Data
{
    T* data;
    std::atomic_uint count;
    bool flag;
};

And it's crashing on `--count;`

Surely this is not a user issue in this case because the pointer should alw=
ays
be 8 bytes, so count should be evenly aligned on a 8-byte boundary. (Unless=
 the
atomic operation needs 16-byte alignment?)

Same code also runs fine when compiled via MSVC and run on Windows, although
it's unclear if this might simply be my Linux test machine running an older=
 ARM
CPU compared to my Windows on ARM test machine.=