It seems the following fragment in the original ConstantPool::copy_cp_to_impl has typos:
  1161 // first part of dest
  1162 Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(0),
  1163 new_operands->adr_at(fillp),
  1164 (len = old_off) * sizeof(u2));
  1165 fillp += len;
  1166 // first part of src
  1167 Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(0),
  1168 new_operands->adr_at(fillp),
  1169 (len = from_off) * sizeof(u2));
  1170 fillp += len;
  1171 // second part of dest
  1172 Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(old_off),
  1173 new_operands->adr_at(fillp),
  1174 (len = old_len - old_off) * sizeof(u2));
  1175 fillp += len;
  1176 // second part of src
  1177 Copy::conjoint_memory_atomic(to_cp->operands()->adr_at(from_off),
  1178 new_operands->adr_at(fillp),
  1179 (len = from_len - from_off) * sizeof(u2));


The lines #1167 and #1177 should have the from_cp instead of the to_cp like this:
  1167 Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(0),
  1177 Copy::conjoint_memory_atomic(from_cp->operands()->adr_at(from_off),