https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71976
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #4) > this is r15 = 40; r18 = r18 << r16; So r18 << 40 which is undefined as 40 > > 16 so GCC decides why not just provide r18 here. Actually I take that back. I missed r18 was DI mode here and not QI mode :).