diff --git a/dune/solvers/iterationsteps/blockgsstep.cc b/dune/solvers/iterationsteps/blockgsstep.cc
index 926445c24adec0d3a7aefbf22388824f2e276bc9..1cb6959a7d807117af993b2ba03448b519cb4b7e 100644
--- a/dune/solvers/iterationsteps/blockgsstep.cc
+++ b/dune/solvers/iterationsteps/blockgsstep.cc
@@ -45,15 +45,13 @@ template<class MatrixType, class DiscFuncType, class BitVectorType>
 inline
 void BlockGSStep<MatrixType, DiscFuncType, BitVectorType>::iterate_step(int i)
 {
-    const MatrixType& mat = *this->mat_;
-
     auto const &ignore_i = this->ignore()[i];
     if (ignore_i.all())
         return;
 
     VectorBlock r;
     residual(i, r);
-    const auto& mat_ii = mat[i][i];
+    const auto& mat_ii = (*this->mat_)[i][i];
 
     // Compute correction v = A_{i,i}^{-1} r[i]
     VectorBlock v;