Merge topic 'teach_brigand_about_cray_compiler'

06c5f161

 Teach brigand about more intel compiler limitations introduced in 18.X.
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1020

vtkm/internal/brigand.hpp

@@ -235,6 +235,19 @@ namespace detail
 }
 namespace brigand
 {
+  template<typename T, typename U>
+  struct same
+  {
+    using type = T;
+  };
+  template<typename T>
+  struct same<T, std::true_type>
+  {
+    static_assert(std::is_same<T, std::true_type>::value, "");
+    using type = T;
+  };
+
+
   namespace detail
   {
     template<class T> struct element_at;
@@ -243,21 +256,20 @@ namespace brigand
     {
       template<class T> type_<T> static at(Ts..., type_<T>*, ...);
 
-      //CUDA 9 version that is required
-      template<class R, class... Other> type_<R> static at_with_type(Ts..., R, Other...);
+      //CUDA 9 and Intel 18 version that is required
+      template<class T, class... Other> T static at_with_type(Ts..., T*, Other...);
     };
 
-    template<class T> T extract_type(type_<T>*);
-
     template<std::size_t N, typename Seq> struct at_impl;
-#if defined(BRIGAND_COMP_CUDA_9)
-    //Only needed for CUDA 9 RC1 as it has some compiler bugs
+#if defined(BRIGAND_COMP_CUDA_9) || defined(BRIGAND_COMP_INTEL)
+    //Both CUDA 9 and the Intel 18 compiler series have a problem deducing the
+    //type so we are just going
     template <std::size_t N, template <typename...> class L, class... Ts>
     struct at_impl<N, L<Ts...>>
     {
       using base_with_type = decltype(
         element_at<filled_list<void const*, N>>::at_with_type(static_cast<type_<Ts>*>(nullptr)...));
-      using type = decltype(extract_type(typename base_with_type::type{}));
+      using type = typename base_with_type::type;
     };
 #else
     // This is the original implementation