Add test for union

Author: maximdimakov

sycl/source/detail/builtins_relational.cpp

@@ -18,8 +18,6 @@ namespace s = cl::sycl;
 namespace d = s::detail;
 
 __SYCL_INLINE_NAMESPACE(cl) {
-namespace sycl {
-} // namespace sycl
 namespace __host_std {
 namespace {
 

sycl/test/basic_tests/types.cpp

@@ -90,7 +90,7 @@ template <> inline void checkSizeForFloatingPoint<s::half, sizeof(int16_t)>() {
 }
 
 int main() {
-  // Test for half constexpr default constructors
+  // Test for creating constexpr expressions
   constexpr sycl::specialization_id<sycl::vec<sycl::half, 2>> id(1.0);
   constexpr sycl::marray<sycl::half, 2> MH(3);
   // Check the size and alignment of the SYCL vectors.

sycl/test/regression/half_union.cpp

@@ -0,0 +1,14 @@
+// RUN: %clangxx -fsycl %s -o %t.out
+// RUN: %RUN_ON_HOST %t.out
+
+#include <CL/sycl.hpp>
+
+typedef union _u16_to_half {
+  unsigned short u;
+  cl::sycl::half h;
+} u16_to_sycl_half;
+
+int main() {
+  u16_to_sycl_half unh;
+  return 0;
+}