Currently most of flags which control instrinsics generation and usage are product:

  product(bool, UseAESIntrinsics, false, \
          "Use intrinsics for AES versions of crypto") \

and some diagnostic:

  diagnostic(ccstrlist, DisableIntrinsic, "", \
          "do not expand intrinsics whose (internal) names appear here") \

By default runtime enables intrinsics on platforms which support them.
The flags are used on command line only when we need to disable intrinsics (or for testing). It is fine to convert all intrinsics flags to diagnostic.