https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94082
--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
clang produces:
<source>:8:5: note: cannot constant evaluate 'memcpy' from object of type
'unsigned char' to object of type 'std::uint32_t' (aka 'unsigned int')
__builtin_memcpy(&num, data, sizeof(std::uint32_t));
^
