diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -4,14 +4,14 @@
 
 function(get_system_libname libpath libname)
   get_filename_component(libpath ${libpath} NAME)
-  if( CMAKE_FIND_LIBRARY_PREFIXES )
-    string(REPLACE ";" "|" PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
-    string(REGEX REPLACE "^(${PREFIXES})" "" libpath ${libpath})
-  endif()
-  if( CMAKE_FIND_LIBRARY_SUFFIXES )
-    string(REPLACE ";" "|" SUFFIXES "${CMAKE_FIND_LIBRARY_SUFFIXES}")
-    string(REGEX REPLACE "(${SUFFIXES})$" "" libpath ${libpath})
-  endif()
+  set(prefixes ${CMAKE_FIND_LIBRARY_PREFIXES})
+  set(suffixes ${CMAKE_FIND_LIBRARY_SUFFIXES})
+  list(FILTER prefixes EXCLUDE REGEX "^\\s*$")
+  list(FILTER suffixes EXCLUDE REGEX "^\\s*$")
+  string(REPLACE ";" "|" prefixes "${prefixes}")
+  string(REPLACE ";" "|" suffixes "${suffixes}")
+  string(REGEX REPLACE "^(${prefixes})" "" libpath ${libpath})
+  string(REGEX REPLACE "(${suffixes})$" "" libpath ${libpath})
   set(${libname} "${libpath}" PARENT_SCOPE)
 endfunction()