template <typename OpT, int... OperandIdx>
struct CompileTimeConstantOperand {
  static_assert(
      sizeof...(OperandIdx) > 0,
      "CompileTimeConstantOperand should have at least one operand index.");

  using OpType = OpT;

  // Returns the indices of operands that should be compile time constants.
  static constexpr std::array<int, sizeof...(OperandIdx)> OperandIndices() {
    return {OperandIdx...};