code: private void enterBinop(String name,
                              Type left, Type right, Type res,
                              int opcode1, int opcode2) {
          enterBinop(
              name, left, right, res, (opcode1 << ByteCodes.preShift) | opcode2);
      }
docs: Enter a binary operation, as above but with two opcodes,
  which get encoded as
  {@code (opcode1 << ByteCodeTags.preShift) + opcode2 }.
  @param opcode1     First opcode.
  @param opcode2     Second opcode.