This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH][RFC][x86] Fix PR91154, add SImode smax, allow SImode add in SSE regs


On Mon, 5 Aug 2019, Uros Bizjak wrote:

> On Mon, Aug 5, 2019 at 3:04 PM Richard Biener <rguenther@suse.de> wrote:
> >
> > On Mon, 5 Aug 2019, Uros Bizjak wrote:
> >
> > > On Mon, Aug 5, 2019 at 2:54 PM Jakub Jelinek <jakub@redhat.com> wrote:
> > > >
> > > > On Mon, Aug 05, 2019 at 02:51:01PM +0200, Uros Bizjak wrote:
> > > > > > (define_mode_iterator MAXMIN_IMODE [SI "TARGET_SSE4_1"] [DI "TARGET_AVX512F"])
> > > > > >
> > > > > > and then we need to split DImode for 32bits, too.
> > > > >
> > > > > For now, please add "TARGET_64BIT && TARGET_AVX512F" for DImode
> > > > > condition, I'll provide _doubleword splitter later.
> > > >
> > > > Shouldn't that be TARGET_AVX512VL instead?  Or does the insn use %g0 etc.
> > > > to force use of %zmmN?
> > >
> > > It generates V4SI mode, so - yes, AVX512VL.
> >
> >     case SMAX:
> >     case SMIN:
> >     case UMAX:
> >     case UMIN:
> >       if ((mode == DImode && (!TARGET_64BIT || !TARGET_AVX512VL))
> >           || (mode == SImode && !TARGET_SSE4_1))
> >         return false;
> >
> > so there's no way to use AVX512VL for 32bit?
> 
> There is a way, but on 32bit targets, we need to split DImode
> operation to a sequence of SImode operations for unconverted pattern.
> This is of course doable, but somehow more complex than simply
> emitting a DImode compare + DImode cmove, which is what current
> splitter does. So, a follow-up task.

Ah, OK.  So for the above condition we can elide the !TARGET_64BIT
check we just need to properly split if we enable the scalar minmax
pattern for DImode on 32bits, the STV conversion would go fine.

Richard.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]