typedef float v4 __attribute__((vector_size(sizeof(float)*4))); typedef struct point { int x; int y; } Point; extern char compile_time_assert[__alignof__(v4) == sizeof(float)*4 ? 1 : -1]; extern char compile_time_assert[__alignof(v4) == sizeof(float)*4 ? 1 : -1]; extern char compile_time_assert[__alignof(v4) == sizeof(float)*4 ? 1 : -1];