message: Fix 32-bit arch expr::pow by using the correct number of bits
diff: @@ -891,7 +891,7 @@ impl<'a, F: FftField> EvalResult<'a, F> {
  fn pow<'b>(self, d: usize, res_domain: (Domain, D<F>)) -> EvalResult<'b, F> {
  let mut acc = EvalResult::Constant(F::one());
  - for i in (0..64).rev() {
  + for i in (0..std::mem::size_of::<usize>() * 8).rev() {
  acc = acc.square(res_domain);
  if (d >> i) & 1 == 1 {
  @@ -1573,7 +1573,7 @@ impl<F: Neg<Output = F> + Clone + One + Zero + PartialEq> Expr<F> {
  let mut acc_is_one = true;
  let x = x.monomials(ev);
  - for i in (0..64).rev() {
  + for i in (0..std::mem::size_of::<usize>() * 8).rev() {
  if !acc_is_one {
  let acc2 = mul_monomials(&acc, &acc);
  acc = acc2;
  