if (matchPattern(op.getInput(), m_Constant(&attr))) {
      auto qtype = op.getQtypeAttr();
      Attribute quantized_attr;
      if (legacy_float_scale_) {
        quantized_attr = quant::QuantizeLegacy(attr, qtype.getValue());
      } else {
        quantized_attr = quant::Quantize(attr, qtype.getValue());
      }
      if (quantized_attr) {
        rewriter.replaceOpWithNewOp<QConstOp>(op, qtype, quantized_attr);

        /*flags=*/true, storage_type, expressed_type, scales, zero_points,
        /*quantizedDimension=*/std::max(adjusted_quant_dim, 0),
        storage_type_min, storage_type_max);
  }
}

ElementsAttr QuantizeLegacy(const Attribute real_value,
                            const Type tensor_type) {
  if (!isa<DenseFPElementsAttr>(real_value) ||
      !quant::QuantizedType::getQuantizedElementType(tensor_type)) {
    return {};
  }

ElementsAttr Quantize(Attribute real_value, Type tensor_type);

// Quantizes the elements in "legacy mode", where it calls TOCO's methods to
// to quantize values with float scale.
ElementsAttr QuantizeLegacy(Attribute real_value, Type tensor_type);

// Returns the quantized type for an element attribute. The quantization
// parameters in this type is based on the min and max element of the