work-around for https://gitlab.kitware.com/cmake/cmake/-/issues/24921

cuvec/CMakeLists.txt

@@ -2,9 +2,6 @@ cmake_minimum_required(VERSION 3.24 FATAL_ERROR)
 if("${CUVEC_BUILD_VERSION}" STREQUAL "")
   set(CUVEC_BUILD_VERSION 2 CACHE STRING "version" FORCE)
 endif()
-if("${CMAKE_CUDA_ARCHITECTURES}" STREQUAL "")
-  set(CMAKE_CUDA_ARCHITECTURES native CACHE STRING "CUDA architectures" FORCE)
-endif()
 project(cuvec LANGUAGES C CXX VERSION "${CUVEC_BUILD_VERSION}")
 
 option(CUVEC_CUDA_OPTIONAL "Make CUDA optional rather than forced" ON)
@@ -29,6 +26,39 @@ else()
     endif()
   endif()
 endif()
+if(CUDAToolkit_FOUND)
+  # work-around for https://gitlab.kitware.com/cmake/cmake/-/issues/24921 to
+  # detect local GPU architectures
+  # (inspired by ${CMAKE_ROOT}/Modules/CMakeTestCUDACompiler.cmake)
+  message(WARNING "overriding CMAKE_CUDA_ARCHITECTURES")
+  include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerABI.cmake)
+  CMAKE_DETERMINE_COMPILER_ABI(CUDA ${CMAKE_ROOT}/Modules/CMakeCUDACompilerABI.cu)
+  if(CMAKE_CUDA_ABI_COMPILED)
+    # Run the test binary to detect the native architectures.
+    execute_process(COMMAND "${CMAKE_PLATFORM_INFO_DIR}/CMakeDetermineCompilerABI_CUDA.bin"
+      RESULT_VARIABLE _CUDA_ARCHS_RESULT
+      OUTPUT_VARIABLE _CUDA_ARCHS_OUTPUT
+      ERROR_VARIABLE  _CUDA_ARCHS_OUTPUT
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if(_CUDA_ARCHS_RESULT EQUAL 0)
+      set(_CUDA_ARCHS "")
+      foreach(_CUDA_ARCH IN LISTS _CUDA_ARCHS_OUTPUT)
+        if(${_CUDA_ARCH}-real IN_LIST CMAKE_CUDA_ARCHITECTURES_ALL OR ${_CUDA_ARCH} IN_LIST CMAKE_CUDA_ARCHITECTURES_ALL)
+          list(APPEND _CUDA_ARCHS ${_CUDA_ARCH})
+        endif()
+      endforeach()
+      unset(_CUDA_ARCH)
+      list(REMOVE_DUPLICATES _CUDA_ARCHS)
+      list(TRANSFORM _CUDA_ARCHS APPEND "-real")
+      set(CMAKE_CUDA_ARCHITECTURES "${_CUDA_ARCHS}" CACHE STRING "CUDA architectures" FORCE)
+      unset(_CUDA_ARCHS)
+    endif()
+    unset(_CUDA_ARCHS_RESULT)
+    unset(_CUDA_ARCHS_OUTPUT)
+  else()
+    set(CMAKE_CUDA_ARCHITECTURES native CACHE STRING "CUDA architectures" FORCE)
+  endif()
+endif()
 if(SKBUILD)
   find_package(PythonExtensions REQUIRED)
   set(LIB_TYPE "MODULE")