Index: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/trunk/cmake/modules/HandleLLVMOptions.cmake
@@ -670,11 +670,6 @@
       append_common_sanitizer_flags()
       append("-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all"
               CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
-      set(BLACKLIST_FILE "${CMAKE_SOURCE_DIR}/utils/sanitizers/ubsan_blacklist.txt")
-      if (EXISTS "${BLACKLIST_FILE}")
-        append("-fsanitize-blacklist=${BLACKLIST_FILE}"
-	              CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
-      endif()
     elseif (LLVM_USE_SANITIZER STREQUAL "Thread")
       append_common_sanitizer_flags()
       append("-fsanitize=thread" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
@@ -706,6 +701,13 @@
   if (LLVM_USE_SANITIZE_COVERAGE)
     append("-fsanitize=fuzzer-no-link" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
   endif()
+  if (LLVM_USE_SANITIZER MATCHES ".*Undefined.*")
+    set(BLACKLIST_FILE "${CMAKE_SOURCE_DIR}/utils/sanitizers/ubsan_blacklist.txt")
+    if (EXISTS "${BLACKLIST_FILE}")
+      append("-fsanitize-blacklist=${BLACKLIST_FILE}"
+             CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+    endif()
+  endif()
 endif()
 
 # Turn on -gsplit-dwarf if requested