Hello Jakub! > On 11 Apr 2018, at 16:27, Jakub Jelinek <ja...@redhat.com> wrote: > > Hi! > > 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 > fine. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? Patch is OK for trunk.
— Thanks, K
