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From: "tnfchris at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/108583] [13 Regression] wrong code with vector division by uint16 at -O2
Date: Thu, 02 Feb 2023 08:55:00 +0000	[thread overview]
Message-ID: <bug-108583-4-w8GkyKwlZJ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108583-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108583

--- Comment #23 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
(In reply to rguenther@suse.de from comment #22)
> On Thu, 2 Feb 2023, tnfchris at gcc dot gnu.org wrote:
> 
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108583
> > 
> > --- Comment #21 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
> > > 
> > > OK, so that's an ADD_HIGHPART_EXPR then?  Though the highpart of an
> > > add is only a single bit, isn't it?  For scalar you'd use the
> > > carry bit here and instructions like adc to consume it.  Is addhn
> > > to do such thing on vectors?
> > > 
> > 
> > So I think this is the only new IFN we'd need. basically we only need one
> > representing (a + b) >> n, for certain values of n we have a single instruction
> > for others we reject it.
> 
> But the ISA only implements n == width(a), so a true "highpart add".
> So I'd add
> 
> OPTAB_D (sadd_highpart_optab, "sadd$a3_highpart")
> OPTAB_D (uadd_highpart_optab, "uadd$a3_highpart")
> 
> only?  That is it's QImode + QImode -> QImode with the carry bit in
> the result (sign or zero-extended)?

Sure that works I think, I'll do that then.

  parent reply	other threads:[~2023-02-02  8:55 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-28 14:00 [Bug rtl-optimization/108583] New: " zsojka at seznam dot cz
2023-01-30  4:19 ` [Bug target/108583] " pinskia at gcc dot gnu.org
2023-01-30  4:22 ` pinskia at gcc dot gnu.org
2023-01-30  8:31 ` rguenth at gcc dot gnu.org
2023-01-30 14:20 ` tnfchris at gcc dot gnu.org
2023-01-30 14:52 ` rguenther at suse dot de
2023-01-30 15:01 ` tnfchris at gcc dot gnu.org
2023-01-30 16:52 ` rsandifo at gcc dot gnu.org
2023-01-30 17:04 ` tnfchris at gcc dot gnu.org
2023-01-31 10:31 ` rguenth at gcc dot gnu.org
2023-01-31 11:01 ` rsandifo at gcc dot gnu.org
2023-01-31 11:39 ` tnfchris at gcc dot gnu.org
2023-01-31 11:44 ` rguenther at suse dot de
2023-01-31 11:58 ` tnfchris at gcc dot gnu.org
2023-01-31 12:03 ` rsandifo at gcc dot gnu.org
2023-01-31 12:19 ` rguenther at suse dot de
2023-01-31 13:35 ` tnfchris at gcc dot gnu.org
2023-01-31 14:33 ` rguenther at suse dot de
2023-01-31 14:45 ` rguenther at suse dot de
2023-01-31 15:01 ` tnfchris at gcc dot gnu.org
2023-02-01  7:29 ` rguenther at suse dot de
2023-02-01 16:22 ` tnfchris at gcc dot gnu.org
2023-02-02  8:03 ` tnfchris at gcc dot gnu.org
2023-02-02  8:50 ` rguenther at suse dot de
2023-02-02  8:55 ` tnfchris at gcc dot gnu.org [this message]
2023-02-08 13:57 ` tnfchris at gcc dot gnu.org
2023-02-09  7:41 ` rguenther at suse dot de
2023-03-12 18:43 ` cvs-commit at gcc dot gnu.org
2023-03-12 18:43 ` cvs-commit at gcc dot gnu.org
2023-03-12 18:43 ` cvs-commit at gcc dot gnu.org
2023-03-12 18:44 ` cvs-commit at gcc dot gnu.org
2023-03-12 18:44 ` cvs-commit at gcc dot gnu.org
2023-03-12 18:45 ` tnfchris at gcc dot gnu.org

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