diff --git a/llvm/cmake/modules/AddLLVMDefinitions.cmake b/llvm/cmake/modules/AddLLVMDefinitions.cmake
--- a/llvm/cmake/modules/AddLLVMDefinitions.cmake
+++ b/llvm/cmake/modules/AddLLVMDefinitions.cmake
@@ -6,12 +6,6 @@
 
 macro(add_llvm_definitions)
   # We don't want no semicolons on LLVM_DEFINITIONS:
-  foreach(arg ${ARGN})
-    if(DEFINED LLVM_DEFINITIONS)
-      set(LLVM_DEFINITIONS "${LLVM_DEFINITIONS} ${arg}")
-    else()
-      set(LLVM_DEFINITIONS ${arg})
-    endif()
-  endforeach(arg)
-  add_definitions( ${ARGN} )
+  list(APPEND LLVM_DEFINITIONS ${ARGN})
+  add_definitions(${ARGN})
 endmacro(add_llvm_definitions)