Fix CUDA minimal build requiring CUDNN_HOME

When building with onnxruntime_CUDA_MINIMAL=ON, cuDNN is not needed
since minimal CUDA builds only use basic CUDA runtime (e.g., for
TensorRT-only builds). Skip cuDNN.cmake inclusion and CUDNN_INCLUDE_DIR
references when CUDA_MINIMAL is enabled.

Fixes #24361

Author: ingyukoh

cmake/external/onnxruntime_external_deps.cmake

@@ -851,12 +851,15 @@ set(onnxruntime_LINK_DIRS)
 if (onnxruntime_USE_CUDA)
   find_package(CUDAToolkit REQUIRED)
 
-  if(onnxruntime_CUDNN_HOME)
-    file(TO_CMAKE_PATH ${onnxruntime_CUDNN_HOME} onnxruntime_CUDNN_HOME)
-    set(CUDNN_PATH ${onnxruntime_CUDNN_HOME})
-  endif()
+  # cuDNN is not needed for minimal CUDA builds (e.g., TensorRT-only builds)
+  if(NOT onnxruntime_CUDA_MINIMAL)
+    if(onnxruntime_CUDNN_HOME)
+      file(TO_CMAKE_PATH ${onnxruntime_CUDNN_HOME} onnxruntime_CUDNN_HOME)
+      set(CUDNN_PATH ${onnxruntime_CUDNN_HOME})
+    endif()
 
-  include(cuDNN)
+    include(cuDNN)
+  endif()
 endif()
 
 if(onnxruntime_USE_SNPE)

cmake/onnxruntime_python.cmake

@@ -113,7 +113,10 @@ endif()
 onnxruntime_add_include_to_target(onnxruntime_pybind11_state Python::Module)
 target_include_directories(onnxruntime_pybind11_state PRIVATE ${ONNXRUNTIME_ROOT} ${pybind11_INCLUDE_DIRS})
 if(onnxruntime_USE_CUDA)
-    target_include_directories(onnxruntime_pybind11_state PRIVATE ${CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES} ${CUDNN_INCLUDE_DIR})
+    target_include_directories(onnxruntime_pybind11_state PRIVATE ${CMAKE_CUDA_TOOLKIT_INCLUDE_DIRECTORIES})
+    if(NOT onnxruntime_CUDA_MINIMAL)
+      target_include_directories(onnxruntime_pybind11_state PRIVATE ${CUDNN_INCLUDE_DIR})
+    endif()
 endif()
 if(onnxruntime_USE_CANN)
     target_include_directories(onnxruntime_pybind11_state PRIVATE ${onnxruntime_CANN_HOME}/include)

cmake/onnxruntime_unittests.cmake

@@ -122,7 +122,10 @@ function(AddTest)
   onnxruntime_add_include_to_target(${_UT_TARGET} date::date flatbuffers::flatbuffers)
   target_include_directories(${_UT_TARGET} PRIVATE ${TEST_INC_DIR})
   if (onnxruntime_USE_CUDA)
-    target_include_directories(${_UT_TARGET} PRIVATE ${CUDAToolkit_INCLUDE_DIRS} ${CUDNN_INCLUDE_DIR})
+    target_include_directories(${_UT_TARGET} PRIVATE ${CUDAToolkit_INCLUDE_DIRS})
+    if(NOT onnxruntime_CUDA_MINIMAL)
+      target_include_directories(${_UT_TARGET} PRIVATE ${CUDNN_INCLUDE_DIR})
+    endif()
     if (onnxruntime_USE_NCCL)
       target_include_directories(${_UT_TARGET} PRIVATE ${NCCL_INCLUDE_DIRS})
     endif()
@@ -1824,7 +1827,10 @@ if (NOT CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
     list(APPEND custom_op_src_patterns
         "${ONNXRUNTIME_SHARED_LIB_TEST_SRC_DIR}/cuda_ops.cu"
         "${TEST_SRC_DIR}/testdata/custom_op_library/cuda/cuda_ops.*")
-    list(APPEND custom_op_lib_include ${CUDAToolkit_INCLUDE_DIRS} ${CUDNN_INCLUDE_DIR})
+    list(APPEND custom_op_lib_include ${CUDAToolkit_INCLUDE_DIRS})
+    if(NOT onnxruntime_CUDA_MINIMAL)
+      list(APPEND custom_op_lib_include ${CUDNN_INCLUDE_DIR})
+    endif()
     if (HAS_QSPECTRE)
       list(APPEND custom_op_lib_option "$<$<COMPILE_LANGUAGE:CUDA>:SHELL:--compiler-options /Qspectre>")
     endif()