diff --git a/llvm/cmake/platforms/WinMsvc.cmake b/llvm/cmake/platforms/WinMsvc.cmake
--- a/llvm/cmake/platforms/WinMsvc.cmake
+++ b/llvm/cmake/platforms/WinMsvc.cmake
@@ -169,6 +169,14 @@
 set(CMAKE_SYSTEM_VERSION 10.0)
 set(CMAKE_SYSTEM_PROCESSOR AMD64)
 
+if (NOT MSVC_VER)
+  get_highest_version("${LLVM_WINSYSROOT}/VC/Tools/MSVC" MSVC_VER)
+endif()
+
+if (NOT WINSDK_VER)
+  get_highest_version("${LLVM_WINSYSROOT}/Windows Kits/10/Include" WINSDK_VER)
+endif()
+
 init_user_prop(HOST_ARCH)
 init_user_prop(LLVM_NATIVE_TOOLCHAIN)
 init_user_prop(LLVM_WINSYSROOT)
@@ -204,14 +212,6 @@
           "binaries")
 endif()
 
-if (NOT MSVC_VER)
-  get_highest_version("${LLVM_WINSYSROOT}/VC/Tools/MSVC" MSVC_VER)
-endif()
-
-if (NOT WINSDK_VER)
-  get_highest_version("${LLVM_WINSYSROOT}/Windows Kits/10/Include" WINSDK_VER)
-endif()
-
 if (NOT LLVM_WINSYSROOT OR NOT MSVC_VER OR NOT WINSDK_VER)
   message(SEND_ERROR
           "Must specify CMake variable LLVM_WINSYSROOT, MSVC_VER and WINSDK_VER")