https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92398
--- Comment #3 from Xiong Hu XS Luo <luoxhu at cn dot ibm.com> --- Power8 BE generates: L.bar: .LFB1: .cfi_startproc mtvsrd 0,4 mtvsrd 1,5 xxpermdi 12,0,1,0 xxlnor 0,12,12 stxvd2x 0,0,3 blr .long 0 .byte 0,0,0,0,0,0,0,0 .cfi_endproc .LFE1: and source code is below for all: void bar (__int128_t *dst, __int128_t src) { *dst = ~src; }