[Bug c++/103699] Reading or writing a constant unaligned value is wrongly optimized causing an incorrect result (GCC-11 and up)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103699

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |INVALID

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Basically you have an aliasing violation.
You are writing as an uint64_t but then reading as uint32_t.
Use either -fno-strict-aliasing or add may_alias attribute to UnalignedUInt32
and UnalignedUInt64.