diff --git a/enzyme/tools/enzyme-tblgen/blas-tblgen.cpp b/enzyme/tools/enzyme-tblgen/blas-tblgen.cpp
index 3e903ed98061..63618b15e028 100644
--- a/enzyme/tools/enzyme-tblgen/blas-tblgen.cpp
+++ b/enzyme/tools/enzyme-tblgen/blas-tblgen.cpp
@@ -918,7 +918,13 @@ void rev_call_arg(DagInit *ruleDag, Rule &rule, size_t actArg, size_t pos,
         return;
       }
       if (Def->getName() == "Concat") {
-        os << "concat_values(";
+        os << "concat_values<";
+        for (size_t i = 0; i < Dag->getNumArgs(); i++) {
+          if (i != 0)
+            os << ", ";
+          os << "ArrayRef<Value*>";
+        }
+        os << ">(";
         for (size_t i = 0; i < Dag->getNumArgs(); i++) {
           if (i != 0)
             os << ", ";