> On 11 Apr 2018, at 16:27, Jakub Jelinek <ja...@redhat.com> wrote:
> In lots of patterns we assume that we never see xmm16+ hard registers
> with 128-bit and 256-bit vector modes when not -mavx512vl, because
> HARD_REGNO_MODE_OK refuses those.
> Unfortunately, as this testcase and patch shows, the vec_extract_lo*
> splitters work as a loophole around this, we happily create instructions
> like (set (reg:V32QI xmm5) (reg:V32QI xmm16)) and then hard register
> propagation can propagate the V32QI xmm16 into other insns like vpand.
> The following patch fixes it by making sure we never create such registers,
> just emit (set (reg:V64QI xmm5) (reg:V64QI xmm16)) instead, which by copying
> all the 512 bits also copies the low bits, and as the destination is
> originally V32QI which is not HARD_REGNO_MODE_OK in xmm16+, this should be
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Patch is OK for trunk.