diff --git a/RecoVertex/GhostTrackFitter/src/GhostTrackPrediction.cc b/RecoVertex/GhostTrackFitter/src/GhostTrackPrediction.cc
index e38139f481ddb..adeaca15389ff 100644
--- a/RecoVertex/GhostTrackFitter/src/GhostTrackPrediction.cc
+++ b/RecoVertex/GhostTrackFitter/src/GhostTrackPrediction.cc
@@ -17,8 +17,9 @@
 using namespace reco;
 
 namespace {
+#ifndef __clang__
   inline double sqr(double arg) { return arg * arg; }
-  
+#endif  
   typedef ROOT::Math::SMatrix<double, 3, 4> Matrix34;
   typedef ROOT::Math::SMatrix<double, 4, 5> Matrix45;
   typedef ROOT::Math::SMatrix<double, 5, 4> Matrix54;
diff --git a/RecoVertex/GhostTrackFitter/src/KalmanGhostTrackUpdater.cc b/RecoVertex/GhostTrackFitter/src/KalmanGhostTrackUpdater.cc
index 159182184bf78..ee89f4a9dd7f4 100644
--- a/RecoVertex/GhostTrackFitter/src/KalmanGhostTrackUpdater.cc
+++ b/RecoVertex/GhostTrackFitter/src/KalmanGhostTrackUpdater.cc
@@ -17,8 +17,9 @@
 using namespace reco;
 
 namespace {
+#ifndef __clang__
 	static inline double sqr(double arg) { return arg * arg; }
-
+#endif
 	using namespace ROOT::Math;
 
 	typedef SVector<double, 4> Vector4;
diff --git a/RecoVertex/GhostTrackFitter/src/VertexGhostTrackState.cc b/RecoVertex/GhostTrackFitter/src/VertexGhostTrackState.cc
index 55df7b4c98ff0..f1a1a88dab005 100644
--- a/RecoVertex/GhostTrackFitter/src/VertexGhostTrackState.cc
+++ b/RecoVertex/GhostTrackFitter/src/VertexGhostTrackState.cc
@@ -13,8 +13,9 @@
 using namespace reco;
 
 namespace {
+#ifndef __clang__
 	static inline double sqr(double arg) { return arg * arg; }
-
+#endif
 	using namespace ROOT::Math;
 
 	typedef SVector<double, 3> Vector3;