diff --git a/src/relay/analysis/annotated_region_set.cc b/src/relay/analysis/annotated_region_set.cc
index c70ef8ae242e1..94c7621e60afc 100644
--- a/src/relay/analysis/annotated_region_set.cc
+++ b/src/relay/analysis/annotated_region_set.cc
@@ -79,7 +79,7 @@ void AnnotatedRegionSetNode::AddToRegion(AnnotatedRegion dest, const Expr& expr)
   }
 }
 
-AnnotatedRegion AnnotatedRegionSetNode::MakeRegion(std::string target) {
+AnnotatedRegion AnnotatedRegionSetNode::MakeRegion(const std::string& target) {
   auto ret = regions_.emplace(AnnotatedRegion());
   (*ret.first)->id_ = region_id_++;
   (*ret.first)->target_ = target;
diff --git a/src/relay/analysis/annotated_region_set.h b/src/relay/analysis/annotated_region_set.h
index cfd044e797760..3bd569387d461 100644
--- a/src/relay/analysis/annotated_region_set.h
+++ b/src/relay/analysis/annotated_region_set.h
@@ -197,7 +197,7 @@ class AnnotatedRegionSetNode : public Object {
    *
    * \return The new region.
    */
-  AnnotatedRegion MakeRegion(std::string target);
+  AnnotatedRegion MakeRegion(const std::string& target);
 
   std::unordered_set<AnnotatedRegion, ObjectHash, ObjectEqual> regions_;
   /*! \brief The next region ID to assign. */