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 0CDE43858D1E; Tue, 20 Jun 2023 16:05:26 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 0CDE43858D1E
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1687277126;
	bh=j7pT8N+0AvGtikWawqq6Ua3YZH07DmNGzVNhsz2vYE0=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=Limbns0gTZxwqAfzoSTuIXfgHJxLZKWH8Y2ctXOMA5SrT7g+6McGoSdLd5M8Xix1J
	 28ZR8LKlHEAb993NU6WcSpshCtrkfSNhwvSqRLTMflD0LRwKnBa0NIn/VemF5kbtyJ
	 x7gKx8fkCxWGjGYntl3wNCLnS8icuYpe91JdnoL4=
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/110237] gcc.dg/torture/pr58955-2.c is
 miscompiled by RTL scheduling after reload
Date: Tue, 20 Jun 2023 16:05:25 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 14.0
X-Bugzilla-Keywords: wrong-code
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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-110237-4-P5GYrCWfZc@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-110237-4@http.gcc.gnu.org/bugzilla/>
References: <bug-110237-4@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
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110237

--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to rguenther@suse.de from comment #5)
> On Tue, 20 Jun 2023, crazylht at gmail dot com wrote:
>=20
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110237
> >=20
> > --- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
> > (In reply to Richard Biener from comment #3)
> > > This looks like the same issue as PR110309.  We have
> > >=20
> > > (insn 38 35 39 3 (set (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22=
 ] [90])
> > >                 (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x2]=20
> > > <var_decl 0x7ffff6e28d80 b>)
> > >                         (const_int -4 [0xfffffffffffffffc])))) [1 MEM
> > > <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32])
> > >         (vec_merge:V16SI (reg:V16SI 20 xmm0 [118])
> > >             (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22 ] [90])=20
> > >                     (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x=
2]=20
> > > <var_decl 0x7ffff6e28d80 b>)
> > >                             (const_int -4 [0xfffffffffffffffc])))) [1=
 MEM
> > > <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32])
> > >=20
> > > so instead of a masked load we see a vec_merge with a (mem:V16SI ...)
> > > based on the vectp_b.12_28 pointer that has full size but the load of=
 b[1]
> > > we try disambiguate against refers to int b[10] which is too small for
> > > a load of 64 bytes so we disambiguate based on that.
> >=20
> >=20
> >   /* If the pointer based access is bigger than the variable they cannot
> >      alias.  This is similar to the check below where we use TBAA to
> >      increase the size of the pointer based access based on the dynamic
> >      type of a containing object we can infer from it.  */
> >   poly_int64 dsize2;
> >   if (known_size_p (size1) --- should be unknown??
> >       && poly_int_tree_p (DECL_SIZE (base2), &dsize2)
> >       && known_lt (dsize2, size1))
> >     return false;
> >=20
> > Should we set MEM_SIZE_KNOWN_P to false for maskstore/maskload?
> > It seems to me maxsize should be 64bytes, but real size should be unkno=
wn.
>=20
> Yes, you shouldn't have MEM_ATTRs that indicate the size is known.

So it looks like a generic problem and better to be handled in
expand_partial_{load, store}_optab_fn?=