message: Avoid triggering undefined behaviour in base_uint<BITS>::bits()
diff: @@ -176,7 +176,7 @@ unsigned int base_uint<BITS>::bits() const
  for (int pos = WIDTH - 1; pos >= 0; pos--) {
  if (pn[pos]) {
  for (int nbits = 31; nbits > 0; nbits--) {
  - if (pn[pos] & 1 << nbits)
  + if (pn[pos] & 1U << nbits)
  return 32 * pos + nbits + 1;
  }
  return 32 * pos + 1;
  