message: Check the result value has single user before using its user iterator
diff: @@ -143,7 +143,9 @@ struct QuantizationPattern : public RewritePattern {
  }
  Type result_ele_type =
  result->getType().cast<TensorType>().getElementType();
  - if (auto user = dyn_cast_or_null<Q>(*result->user_begin())) {
  + // If the user is the Quantize op, it must be the only user.
  + if (result->hasOneUse() && llvm::isa<Q>(*result->user_begin())) {
  + auto user = llvm::cast<Q>(*result->user_begin());
  outputs_replaced.insert({user.output(), enumerated_result.index()});
  output_types.push_back(user.getType());
  } else if (result_ele_type.template isa<IntegerType>()) {
  