https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102178
--- Comment #9 from Hongtao.liu <crazylht at gmail dot com> ---
1703 : 401cb1: vmovq %xmm1,%r9 (*)
834 : 401cb6: vmovq %r8,%xmm1
1719 : 401cbb: vmovq %r9,%xmm0 (*)
Look like %r9 is dead after the second (*), and it can be optimized to
1703 : 401cb1: vmovq %xmm1,%xmm0
834 : 401cb6: vmovq %r8,%xmm1
