https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109950
Alexander Monakov <amonakov at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |amonakov at gcc dot gnu.org --- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> --- That's the REX prefix, not an operand size override prefix. It doesn't cause a decoding stall.