diff --git a/dune/solvers/iterationsteps/cgstep.cc b/dune/solvers/iterationsteps/cgstep.cc
index f95821e45df9214e3efe0be84000da3fd030feb3..13fa1432b21f1703bba20aacabd873ab78d3ecb6 100644
--- a/dune/solvers/iterationsteps/cgstep.cc
+++ b/dune/solvers/iterationsteps/cgstep.cc
@@ -17,7 +17,7 @@ void CGStep<MatrixType, VectorType>::preprocess()
     } else
         p_ = r_;
 
-    r_squared_old = p_*r_;
+    r_squared_old_ = p_*r_;
 }
 
 template <class MatrixType, class VectorType>
@@ -26,7 +26,7 @@ void CGStep<MatrixType, VectorType>::iterate()
     VectorType q(x_);
 
     matrix_.mv(p_, q);                             // q_0     = Ap_0
-    const double alpha = r_squared_old / (p_ * q); // alpha_0 = r_0*r_0/p_0*Ap_0
+    const double alpha = r_squared_old_ / (p_ * q); // alpha_0 = r_0*r_0/p_0*Ap_0
     x_.axpy(alpha, p_);                            // x_1     = x_0 + alpha_0 p_0
     r_.axpy(-alpha, q);                            // r_1     = r_0 - alpha_0 Ap_0
 
@@ -36,8 +36,8 @@ void CGStep<MatrixType, VectorType>::iterate()
         q = r_;
 
     const double r_squared = q * r_;
-    const double beta = r_squared / r_squared_old; // beta_0 = r_1*r_1/ (r_0*r_0)
+    const double beta = r_squared / r_squared_old_; // beta_0 = r_1*r_1/ (r_0*r_0)
     p_ *= beta;                                    // p_1 = r_1 + beta_0 p_0
     p_ += q;
-    r_squared_old = r_squared;
+    r_squared_old_ = r_squared;
 }
diff --git a/dune/solvers/iterationsteps/cgstep.hh b/dune/solvers/iterationsteps/cgstep.hh
index f782bae6103870dfa476b0d2b721355f5edd12ca..97f9e9be94440be3875cf830369dfbf404fe3b58 100644
--- a/dune/solvers/iterationsteps/cgstep.hh
+++ b/dune/solvers/iterationsteps/cgstep.hh
@@ -38,7 +38,7 @@ namespace Dune {
             VectorType r_; // residual
             VectorType& x_;
             const MatrixType& matrix_;
-            double r_squared_old;
+            double r_squared_old_;
             Preconditioner<MatrixType, VectorType>* preconditioner_;
         };