https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64537
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to kugan from comment #1) > According to AAPCS64 > (http://infocenter.arm.com/help/topic/com.arm.doc.ihi0055c/ > IHI0055C_beta_aapcs64.pdf), the unused parm register bits have "unspecified > value".So I think it is Needed It is not needed because the next instruction has a sign extend and the other uses of the result of the sign extend only use the lower 32bits of the register.
