skip -= e->skip_n_vectors * sizeof (u32x4);
e->rewrite_n_vectors = (skip + len - 1) / sizeof (u32x4) + 1;
vec_alloc_aligned (e->mask, e->rewrite_n_vectors, sizeof (u32x4));
skip -= e->skip_n_vectors * sizeof (u32x4);
e->rewrite_n_vectors = (skip + len - 1) / sizeof (u32x4) + 1;
vec_alloc_aligned (e->mask, e->rewrite_n_vectors, sizeof (u32x4));