Change code according to review

Source/Math/CntkBatchNormalization.cuh

@@ -108,12 +108,13 @@ __device__ __forceinline__ void StoreValues<4, float>(const float src[4], float*
 template <typename T>
 __device__ __forceinline__ T Shuffle(T input, int srcLane)
 {
-#if __CUDA_ARCH__ >= 300
+#ifdef __CUDA_ARCH__
     // shfl is supported only on Kepler+
+    static_assert(__CUDA_ARCH__ >= 300, "CNTK only supports only Kepler GPU architecture or newer");
     return cub::ShuffleIndex(input, srcLane);
 #else
     assert(false);
-    return input; // keep compiler happy
+    return input;
 #endif
 }
 

Source/Math/MathCUDA.vcxproj

@@ -52,7 +52,7 @@
   <PropertyGroup Label="UserMacros" />
   <PropertyGroup Condition="$(DebugBuild)">
     <CudaCodeGen>$(CNTK_CUDA_CODEGEN_DEBUG)</CudaCodeGen>
-    <CudaCodeGen Condition="'$(CudaCodeGen)'==''">compute_20,sm_20;compute_30,sm_30</CudaCodeGen>
+    <CudaCodeGen Condition="'$(CudaCodeGen)'==''">compute_30,sm_30</CudaCodeGen>
   </PropertyGroup>
   <PropertyGroup Condition="$(ReleaseBuild)">
     <CudaCodeGen>$(CNTK_CUDA_CODEGEN_RELEASE)</CudaCodeGen>