// a general mlir::Operation.
//
// The signature of the function is:
//
//   std::optional<Flatbuffers::Offset<tflite::Operator>>
//   mlir::CreateFlatBufferOperator(
//       mlir::Operation* op,
//       uint32_t opcode_index,
//       const std::vector<int32_t>& operands,
//       const std::vector<int32_t>& results,
//       const std::vector<int32_t>& intermediates,

// Returns the FlatBuffer offset for the operator on success; emits error and
// returns std::nullopt on failure.
std::optional<flatbuffers::Offset<tflite::Operator>> CreateFlatBufferOperator(
    Operation *mlir_op, uint32_t opcode_index,
    const std::vector<int32_t> &operands, const std::vector<int32_t> &results,
    const std::vector<int32_t> &intermediates,
    flatbuffers::FlatBufferBuilder *fbb);

    if (*builtin_code == tflite::BuiltinOperator_TRANSPOSE_CONV) {
      if (operands.size() == 4 && operands.at(3) == -1) {
        operands.pop_back();
      }
    }

    auto offset = CreateFlatBufferOperator(inst, opcode_index, operands,
                                           results, intermediates, &builder_);
    if (!offset) {
      inst->emitOpError("is not a supported TFLite op");
    }