From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id DA8D83890438; Thu, 13 Jan 2022 12:40:18 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DA8D83890438
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103771] [12 Regression] Missed vectorization under
 -mavx512f -mavx512vl after r12-5489
Date: Thu, 13 Jan 2022 12:40:18 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Version: 12.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: crazylht at gmail dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.0
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-103771-4-x9SPwYqKvh@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-103771-4@http.gcc.gnu.org/bugzilla/>
References: <bug-103771-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Thu, 13 Jan 2022 12:40:19 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103771

--- Comment #15 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to rguenther@suse.de from comment #12)
> On Thu, 13 Jan 2022, crazylht at gmail dot com wrote:
>=20
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103771
> >=20
> > --- Comment #10 from Hongtao.liu <crazylht at gmail dot com> ---
> > with
> > @@ -12120,7 +12120,8 @@ supportable_narrowing_operation (enum tree_code=
 code,
> >        c1 =3D VEC_PACK_TRUNC_EXPR;
> >        if (VECTOR_BOOLEAN_TYPE_P (narrow_vectype)
> >           && VECTOR_BOOLEAN_TYPE_P (vectype)
> > -         && TYPE_MODE (narrow_vectype) =3D=3D TYPE_MODE (vectype)
> > +         && (TYPE_MODE (narrow_vectype) =3D=3D TYPE_MODE (vectype)
> > +             || known_lt (TYPE_VECTOR_SUBPARTS (vectype), BITS_PER_UNI=
T))
> >           && SCALAR_INT_MODE_P (TYPE_MODE (vectype)))
>=20
> I think we instead simply want
>=20
>          if (VECTOR_BOOLEAN_TYPE_P (narrow_vectype)
>              && TYPE_PRECISION (TREE_TYPE (narrow_vectype)) =3D=3D 1
>              && VECTOR_BOOLEAN_TYPE_P (vectype)
>              && TYPE_PRECISION (TREE_TYPE (vectype)) =3D=3D 1)
>=20
> note the docs of vec_pack_sbool_trunc say
>=20
> This instruction pattern is used when all the vector input and output
> operands have the same scalar mode @var{m} and thus using
> @code{vec_pack_trunc_@var{m}} would be ambiguous.
>=20
> It also says "_Narrow_ and merge the elements of two vectors.", I think
> "narrow" is misleading here, _trunc in the optab name as well.  So
> with the above it suggests we could have used vect_pack_trunc_hi here?
>=20
> To avoid breaking things for the VnBImode using targets we probably
> want to retain the SCALAR_INT_MODE_P (prev_mode) check.  And we
> probably want to adjust the documentation a bit.
>=20
> This all is with my pasted pattern patch or is this with the weird
> inserted conversion still?

It's w/o your patch, I'm try to handle the weird conversion with multi
steps(first pack QI:4 -> QI:8 through vec_pack_sbool_trunc_qi, then pack QI=
:8
-> HI:16 through vec_pack_sbool_trunc_hi). But on the othersize the weird
inserted conversion shouldn't be existed.=