Region &region = mhlo_op.getBodyRegion(idx);
      rewriter.inlineRegionBefore(op.getBodyRegion(idx), region, region.end());

      // Update region's entry blocks argument types to handle quantized element
      // types.
      if constexpr (std::is_same<DstOpT, mhlo::WhileOp>::value) {
        TypeConverter::SignatureConversion signature(num_results);
        Block &block = region.front();