diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index b30d002aa205..3e2879bf3bef 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1193,6 +1193,7 @@ function(add_lit_target target comment)
     list(APPEND LIT_ARGS --param build_mode=${CMAKE_CFG_INTDIR})
   endif ()
 
+  set(suffix "")
   if (WIN32 AND NOT CYGWIN)
     # llvm-lit needs suffix.py for multiprocess to find a main module.
     set(suffix .py)