diff --git a/benchmarks/dvmp/analysis/vm_invar.cxx b/benchmarks/dvmp/analysis/vm_invar.cxx
index 599981f34e7fc95f8745bb6de94f6adfbe89ce99..4325b94838be40bdca0657614d7324e2a005ca4b 100644
--- a/benchmarks/dvmp/analysis/vm_invar.cxx
+++ b/benchmarks/dvmp/analysis/vm_invar.cxx
@@ -145,6 +145,7 @@ int vm_invar(const std::string& config_name)
       RawhistName[i][j] = VarName[i] + "_" + VarCate[j];
       //get histograms
       auto h_tmp = d_im.Histo1D({fmt::format("{}_tmp", histName[i][j]).c_str(), histTitles[i][j].c_str(), 50, range_l[i][j], range_h[i][j]}, RawhistName[i][j].c_str());
+      auto& htmp = *h_tmp;
       //TH1D* hptr_tmp = &(*h_tmp);
       //h_Var1D[i][j] = (TH1D*)hptr_tmp->Clone(histName[i][j].c_str());
       //delete hptr_tmp;