Index: cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- cmake/modules/HandleLLVMOptions.cmake
+++ cmake/modules/HandleLLVMOptions.cmake
@@ -584,6 +584,10 @@
   check_cxx_compiler_flag("-Wclass-memaccess" CXX_SUPPORTS_CLASS_MEMACCESS_FLAG)
   append_if(CXX_SUPPORTS_CLASS_MEMACCESS_FLAG "-Wno-class-memaccess" CMAKE_CXX_FLAGS)
 
+  # The LLVM libraries have no stable C++ API, so -Wnoexcept-type is not useful.
+  check_cxx_compiler_flag("-Wnoexcept-type" CXX_SUPPORTS_NOEXCEPT_TYPE_FLAG)
+  append_if(CXX_SUPPORTS_NOEXCEPT_TYPE_FLAG "-Wno-noexcept-type" CMAKE_CXX_FLAGS)
+
   # Check if -Wnon-virtual-dtor warns even though the class is marked final.
   # If it does, don't add it. So it won't be added on clang 3.4 and older.
   # This also catches cases when -Wnon-virtual-dtor isn't supported by