https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98366
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- But struct S { int b; int alignment; int c : 7; int d : 8; int e : 17; } const e[] = {{0, 3, '(', 2, 0}}; typedef struct S S; int memcmp (const void *, const void *, __SIZE_TYPE__); int main () { _Bool b = (!memcmp(e, (S[]){{.alignment = 3, '(', 2, 0}}, sizeof (S))); if (!b) __builtin_abort (); } should be valid because there is no padding but it aborts anyway, I think the code mishandles bitfields.