[Bug middle-end/110773] [Aarch64] crash (SIGBUS) due to atomic instructions on under-aligned memory

["sainan+gcc.bugzilla at calamity dot gg" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110773

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

           What    |Removed                     |Added
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                 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 like
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 always
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.