https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43798
--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> --- IMHO if we silently lower alignment of UINT192 as array elements we should at least warn for typedef __attribute__((aligned(16))) struct { unsigned long long w[3]; } UINT192; UINT192 bid_Kx192[32]; like UINT192 bid_Kx192[32]; ^^^^^^^ warning: alignment of array element type lowered to 8 note: accesses via UINT192 * might generate wrong code which IMHO is a reason to reject this. Can the bogus situation be reproduced with C _Alignas?