diff --git a/Eigen/src/Core/products/TriangularMatrixMatrix.h b/Eigen/src/Core/products/TriangularMatrixMatrix.h
index 4b6301bde..cca740250 100644
--- a/Eigen/src/Core/products/TriangularMatrixMatrix.h
+++ b/Eigen/src/Core/products/TriangularMatrixMatrix.h
@@ -99,7 +99,7 @@ struct product_triangular_matrix_matrix<Scalar,Index,Mode,true,
   
   typedef gebp_traits<Scalar,Scalar> Traits;
   enum {
-    SmallPanelWidth   = EIGEN_PLAIN_ENUM_MAX(Traits::mr,Traits::nr),
+    SmallPanelWidth   = 2 * EIGEN_PLAIN_ENUM_MAX(Traits::mr,Traits::nr),
     IsLower = (Mode&Lower) == Lower,
     SetDiag = (Mode&(ZeroDiag|UnitDiag)) ? 0 : 1
   };