FindCUDAToolkit: Use CUDA compiler path even when CUDA lang not enabled

Fixes: #25567

3 files changed, 31 insertions, 0 deletions

diff --git a/Tests/Cuda/CMakeLists.txt b/Tests/Cuda/CMakeLists.txt
index 04ef86d..c1952c5 100644
--- a/Tests/Cuda/CMakeLists.txt
+++ b/Tests/Cuda/CMakeLists.txt
@@ -27,6 +27,7 @@ add_cuda_test_macro(Cuda.ProperLinkFlags ProperLinkFlags)
 if(CMake_TEST_CUDA AND NOT CMake_TEST_CUDA STREQUAL "Clang")
   # Clang lacks __CUDACC_VER*__ defines.
   add_cuda_test_macro(Cuda.ProperDeviceLibraries ProperDeviceLibraries)
+  add_cuda_test_macro(Cuda.ToolkitBeforeLang ToolkitBeforeLang)
 endif()
 
 add_cuda_test_macro(Cuda.WithC CudaWithC)
diff --git a/Tests/Cuda/ToolkitBeforeLang/CMakeLists.txt b/Tests/Cuda/ToolkitBeforeLang/CMakeLists.txt
new file mode 100644
index 0000000..6b97a21
--- /dev/null
+++ b/Tests/Cuda/ToolkitBeforeLang/CMakeLists.txt
@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.15)
+project(ToolkitBeforeLang CXX)
+
+#Goal for this example:
+# Validate that we use the same CUDA Toolkit as `enable_language(CUDA)` would find
+find_package(CUDAToolkit REQUIRED)
+
+if(NOT DEFINED CUDAToolkit_VERSION)
+  message(FATAL_ERROR "expected CUDAToolkit variable CUDAToolkit_VERSION not found")
+endif()
+
+enable_language(CUDA)
+
+message(STATUS "CUDAToolkit_NVCC_EXECUTABLE ${CUDAToolkit_NVCC_EXECUTABLE}")
+message(STATUS "CMAKE_CUDA_COMPILER ${CMAKE_CUDA_COMPILER}")
+
+if( NOT CUDAToolkit_NVCC_EXECUTABLE STREQUAL CMAKE_CUDA_COMPILER)
+  message(FATAL_ERROR "CUDAToolkit_NVCC_EXECUTABLE ${CUDAToolkit_NVCC_EXECUTABLE} doesn't match CMAKE_CUDA_COMPILER ${CMAKE_CUDA_COMPILER}")
+endif()
+
+add_executable(ToolkitBeforeLang main.cpp)
+target_link_libraries(ToolkitBeforeLang PRIVATE CUDA::toolkit)
diff --git a/Tests/Cuda/ToolkitBeforeLang/main.cpp b/Tests/Cuda/ToolkitBeforeLang/main.cpp
new file mode 100644
index 0000000..c8d5c6b
--- /dev/null
+++ b/Tests/Cuda/ToolkitBeforeLang/main.cpp
@@ -0,0 +1,8 @@
+// Only thing we care about is that these headers are found
+#include <cuda.h>
+#include <cuda_runtime_api.h>
+
+int main()
+{
+  return 0;
+}