https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67002
--- Comment #7 from Kazumoto Kojima <kkojima at gcc dot gnu.org> --- (In reply to John Paul Adrian Glaubitz from comment #6) > And here is the diff from the disassembly: A rare indeterminacy of the register choice. Both codes are valid. It seems very hard to find where has this indeterminacy come from. Please follow Oleg's suggestion #c1.