diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
index 88d51e5f0..d01a63ccb 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
@@ -345,8 +345,9 @@ template <typename Self, typename Op, typename Device>
 struct InnerReducer {
   static const bool HasOptimizedImplementation = false;
 
-  EIGEN_DEVICE_FUNC static void run(const Self&, Op&, const Device&, typename Self::CoeffReturnType*, typename Self::Index, typename Self::Index) {
+  EIGEN_DEVICE_FUNC static bool run(const Self&, Op&, const Device&, typename Self::CoeffReturnType*, typename Self::Index, typename Self::Index) {
     eigen_assert(false && "Not implemented");
+    return true;
   }
 };
 
@@ -355,8 +356,9 @@ template <typename Self, typename Op, typename Device>
 struct OuterReducer {
   static const bool HasOptimizedImplementation = false;
 
-  EIGEN_DEVICE_FUNC static void run(const Self&, Op&, const Device&, typename Self::CoeffReturnType*, typename Self::Index, typename Self::Index) {
+  EIGEN_DEVICE_FUNC static bool run(const Self&, Op&, const Device&, typename Self::CoeffReturnType*, typename Self::Index, typename Self::Index) {
     eigen_assert(false && "Not implemented");
+    return true;
   }
 };
 
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
index c3b1b8b7a..bad5c1425 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReductionCuda.h
@@ -226,8 +226,9 @@ struct InnerReducer<Self, Op, GpuDevice> {
                                                  internal::is_same<typename Self::CoeffReturnType, float>::value;
 
   template <typename Device, typename OutputType>
-  static EIGEN_DEVICE_FUNC void run(const Self&, Op&, const Device&, OutputType*, typename Self::Index, typename Self::Index) {
+  static EIGEN_DEVICE_FUNC bool run(const Self&, Op&, const Device&, OutputType*, typename Self::Index, typename Self::Index) {
     assert(false && "Should only be called to reduce floats on a gpu device");
+    return true;
   }
 
   static EIGEN_DEVICE_FUNC bool run(const Self& self, Op& reducer, const GpuDevice& device, float* output, typename Self::Index num_coeffs_to_reduce, typename Self::Index num_preserved_vals) {
@@ -304,8 +305,9 @@ struct OuterReducer<Self, Op, GpuDevice> {
                                                  internal::is_same<typename Self::CoeffReturnType, float>::value;
 
   template <typename Device, typename OutputType>
-  static EIGEN_DEVICE_FUNC void run(const Self&, Op&, const Device&, OutputType*, typename Self::Index, typename Self::Index) {
+  static EIGEN_DEVICE_FUNC bool run(const Self&, Op&, const Device&, OutputType*, typename Self::Index, typename Self::Index) {
     assert(false && "Should only be called to reduce floats on a gpu device");
+    return true;
   }
 
   static EIGEN_DEVICE_FUNC bool run(const Self& self, Op& reducer, const GpuDevice& device, float* output, typename Self::Index num_coeffs_to_reduce, typename Self::Index num_preserved_vals) {