https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84226
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2018-02-08 CC| |dje at gcc dot gnu.org, | |jakub at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Seems the rs6000 backend violates BSWAP requirements: @item (bswap:@var{m} @var{x}) Represents the value @var{x} with the order of bytes reversed, carried out in mode @var{m}, which must be a fixed-point machine mode. The mode of @var{x} must be @var{m} or @code{VOIDmode}. V2DFmode or V4SFmode are not integral modes. So, I'd say that instead of using these p9_xxbrd_v2df and p9_xxbrw_v4sf patterns the backend instead should subreg the operand to v2di or v4si, do p9_xxbrd_v2di or p9_xxbrw_v4si and finally subreg the result to v2df/v4sf. Or the documentation needs to be changed and simplify_const_unary_operation extended to handle that case (possibly by handling it using simplifying const subreg to corresponding integral mode, doing bswap on the integral mode and then subreg back.