https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87984
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The old documentation had the following: Stores into local register variables may be deleted when they appear to be dead according to dataflow analysis. References to local register variables may be deleted or moved or simplified. I can't seem to find that in the newer one but it still applies here.
