diff --git a/Eigen/src/Core/arch/CUDA/PacketMathHalf.h b/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
index dcb948c5a..8931f4662 100644
--- a/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
+++ b/Eigen/src/Core/arch/CUDA/PacketMathHalf.h
@@ -262,7 +262,7 @@ template<> EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Eigen::half predux_mul<half2>(c
 #else
   float a1 = __low2float(a);
   float a2 = __high2float(a);
-  return Eigen::half(internal::raw_uint16_to_half(__float2half_rn(a1 * a2)));
+  return Eigen::half(half_impl::raw_uint16_to_half(__float2half_rn(a1 * a2)));
 #endif
 }
 
diff --git a/test/boostmultiprec.cpp b/test/boostmultiprec.cpp
index a83ae4b78..b4d0decff 100644
--- a/test/boostmultiprec.cpp
+++ b/test/boostmultiprec.cpp
@@ -71,6 +71,18 @@ namespace Eigen {
 
   template<>
   Real test_precision<Real>() { return 1e-50; }
+
+  // needed in C++93 mode where number does not support explicit cast.
+  namespace internal {
+    template<typename NewType>
+    struct cast_impl<Real,NewType>
+    {
+      static inline NewType run(const Real& x)
+      {
+        return x.template convert_to<NewType>();
+      }
+    };
+  }
 }
 
 namespace boost {
diff --git a/unsupported/test/cxx11_tensor_of_float16_cuda.cu b/unsupported/test/cxx11_tensor_of_float16_cuda.cu
index 34e9f54a0..b6df5a4d2 100644
--- a/unsupported/test/cxx11_tensor_of_float16_cuda.cu
+++ b/unsupported/test/cxx11_tensor_of_float16_cuda.cu
@@ -21,6 +21,7 @@ using Eigen::Tensor;
 
 #ifdef EIGEN_HAS_CUDA_FP16
 
+template<typename>
 void test_cuda_conversion() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -55,7 +56,7 @@ void test_cuda_conversion() {
   gpu_device.deallocate(d_conv);
 }
 
-
+template<typename>
 void test_cuda_unary() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -92,7 +93,7 @@ void test_cuda_unary() {
   gpu_device.deallocate(d_res_float);
 }
 
-
+template<typename>
 void test_cuda_elementwise() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -134,6 +135,7 @@ void test_cuda_elementwise() {
   gpu_device.deallocate(d_res_float);
 }
 
+template<typename>
 void test_cuda_trancendental() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -186,7 +188,10 @@ void test_cuda_trancendental() {
   }
   for (int i = 0; i < num_elem; ++i) {
     std::cout << "Checking elemwise log " << i << " input = " << input2(i) << " full = " << full_prec2(i) << " half = " << half_prec2(i) << std::endl;
-    VERIFY_IS_APPROX(full_prec2(i), half_prec2(i));
+    if(std::abs(input2(i)-1.f)<0.05f) // log lacks accurary nearby 1
+      VERIFY_IS_APPROX(full_prec2(i)+Eigen::half(0.1f), half_prec2(i)+Eigen::half(0.1f));
+    else
+      VERIFY_IS_APPROX(full_prec2(i), half_prec2(i));
   }
   gpu_device.deallocate(d_float1);
   gpu_device.deallocate(d_float2);
@@ -196,7 +201,7 @@ void test_cuda_trancendental() {
   gpu_device.deallocate(d_res2_float);
 }
 
-
+template<typename>
 void test_cuda_contractions() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -247,7 +252,7 @@ void test_cuda_contractions() {
   gpu_device.deallocate(d_res_float);
 }
 
-
+template<typename>
 void test_cuda_reductions(int size1, int size2, int redux) {
 
    std::cout << "Reducing " << size1 << " by " << size2
@@ -296,17 +301,19 @@ void test_cuda_reductions(int size1, int size2, int redux) {
   gpu_device.deallocate(d_res_float);
 }
 
+template<typename>
 void test_cuda_reductions() {
-  test_cuda_reductions(13, 13, 0);
-  test_cuda_reductions(13, 13, 1);
+  test_cuda_reductions<void>(13, 13, 0);
+  test_cuda_reductions<void>(13, 13, 1);
 
-  test_cuda_reductions(35, 36, 0);
-  test_cuda_reductions(35, 36, 1);
+  test_cuda_reductions<void>(35, 36, 0);
+  test_cuda_reductions<void>(35, 36, 1);
 
-  test_cuda_reductions(36, 35, 0);
-  test_cuda_reductions(36, 35, 1);
+  test_cuda_reductions<void>(36, 35, 0);
+  test_cuda_reductions<void>(36, 35, 1);
 }
 
+template<typename>
 void test_cuda_full_reductions() {
   Eigen::CudaStreamDevice stream;
   Eigen::GpuDevice gpu_device(&stream);
@@ -355,7 +362,7 @@ void test_cuda_full_reductions() {
   gpu_device.deallocate(d_res_float);
 }
 
-
+template<typename>
 void test_cuda_forced_evals() {
 
   Eigen::CudaStreamDevice stream;
@@ -409,14 +416,14 @@ void test_cuda_forced_evals() {
 void test_cxx11_tensor_of_float16_cuda()
 {
 #ifdef EIGEN_HAS_CUDA_FP16
-  CALL_SUBTEST_1(test_cuda_conversion());
-  CALL_SUBTEST_1(test_cuda_unary());
-  CALL_SUBTEST_1(test_cuda_elementwise());
-  CALL_SUBTEST_1(test_cuda_trancendental());
-  CALL_SUBTEST_2(test_cuda_contractions());
-  CALL_SUBTEST_3(test_cuda_reductions());
-  CALL_SUBTEST_4(test_cuda_full_reductions());
-  CALL_SUBTEST_5(test_cuda_forced_evals());
+  CALL_SUBTEST_1(test_cuda_conversion<void>());
+  CALL_SUBTEST_1(test_cuda_unary<void>());
+  CALL_SUBTEST_1(test_cuda_elementwise<void>());
+  CALL_SUBTEST_1(test_cuda_trancendental<void>());
+  CALL_SUBTEST_2(test_cuda_contractions<void>());
+  CALL_SUBTEST_3(test_cuda_reductions<void>());
+  CALL_SUBTEST_4(test_cuda_full_reductions<void>());
+  CALL_SUBTEST_5(test_cuda_forced_evals<void>());
 #else
   std::cout << "Half floats are not supported by this version of cuda: skipping the test" << std::endl;
 #endif