[BUG]Incorrect usage of variable in CMakeLists.txt

[x12301450]

In mlir/lib/Target/LLVM/CMakeLists.txt, the variable CUDAToolkit_LIBRARY_ROOT is used in the following way in Line 66:

set(MLIR_CUDAToolkit_ROOT ${CUDAToolkit_LIBRARY_ROOT})

and like this in Line 135:

find_file(MLIR_NVVM_LIBDEVICE_PATH libdevice.10.bc
                PATHS ${CUDAToolkit_LIBRARY_ROOT}
                PATH_SUFFIXES "nvvm/libdevice" NO_DEFAULT_PATH REQUIRED)

However, when checking whether the variable is defined, it is done in the following way in Line 62:

if(NOT DEFINED ${CUDAToolkit_LIBRARY_ROOT})

This if command doesn't take effect when CUDAToolkit_LIBRARY_ROOT simply represent a path. I think the correct way to write it should be:

if(NOT DEFINED CUDAToolkit_LIBRARY_ROOT)

Looking forward to your feedback!