https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117256
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I thought I've guarded that in main with
if (__builtin_offsetof (A, c) == 0
&& __builtin_offsetof (A, i) != 1
&& __builtin_offsetof (B, a) == 0
&& sizeof (A) == sizeof (B))
so the testing is only done if A.c is at offset 0, A.i is not at offset 1 (I
assume it can't be at offset 0 either) and B.a is at offset 0 and A is the same
size as B.
Perhaps the third check is redundant with the 4th.
