CUDA: Add CudaOnly.CompileFlags test

Covers passing compile flags explicitly for both NVCC and Clang.

Tests/CudaOnly/CMakeLists.txt

@@ -1,6 +1,7 @@
 
 ADD_TEST_MACRO(CudaOnly.Architecture Architecture)
 ADD_TEST_MACRO(CudaOnly.CircularLinkLine CudaOnlyCircularLinkLine)
+ADD_TEST_MACRO(CudaOnly.CompileFlags CudaOnlyCompileFlags)
 ADD_TEST_MACRO(CudaOnly.EnableStandard CudaOnlyEnableStandard)
 ADD_TEST_MACRO(CudaOnly.ExportPTX CudaOnlyExportPTX)
 ADD_TEST_MACRO(CudaOnly.GPUDebugFlag CudaOnlyGPUDebugFlag)

Tests/CudaOnly/CompileFlags/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.17)
+cmake_policy(SET CMP0104 OLD)
+project(CompileFlags CUDA)
+
+# Clear defaults.
+set(CMAKE_CUDA_ARCHITECTURES)
+
+add_executable(CudaOnlyCompileFlags main.cu)
+
+# Try passing CUDA architecture flags explicitly.
+if(CMAKE_CUDA_COMPILER_ID STREQUAL "NVIDIA")
+  target_compile_options(CudaOnlyCompileFlags PRIVATE
+    -gencode arch=compute_50,code=compute_50
+    --compiler-options=-DHOST_DEFINE
+  )
+endif()

Tests/CudaOnly/CompileFlags/main.cu

@@ -0,0 +1,16 @@
+#ifdef __CUDA_ARCH__
+#  if __CUDA_ARCH__ != 500
+#    error "Passed architecture 50, but got something else."
+#  endif
+#endif
+
+// Check HOST_DEFINE only for nvcc
+#ifndef __CUDA__
+#  ifndef HOST_DEFINE
+#    error "HOST_DEFINE not defined!"
+#  endif
+#endif
+
+int main()
+{
+}