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 E30D73858C66; Fri, 12 Apr 2024 10:40:15 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E30D73858C66
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1712918416;
	bh=xMCnu4aAMn8gGa3ZOTVn2F/63/MhoH62rEAcw5PPrrY=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=Q2bj+JwecJAFKTd/0wMaNFnUhvvjiVqpQqf2i4qFEn7s+EDQEDc8liTxR82h/udUq
	 CXJ/+bRy+0KgNHYFexUADauEsmht4/LuEbdS3EUJjoTciXbyM9CDYqRamxaHumSne2
	 //9GX6MOk8dGQC+hm3uYPpfM+Ox2Mr2qHDwlQcRc=
From: "rearnsha at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/111231] [12/13/14 regression] armhf: Miscompilation with
 -O2/-fno-exceptions level (-fno-tree-vectorize is working)
Date: Fri, 12 Apr 2024 10:40:14 +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: 13.2.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rearnsha at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 12.4
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-111231-4-LDPMmQnltf@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-111231-4@http.gcc.gnu.org/bugzilla/>
References: <bug-111231-4@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=3D111231

--- Comment #27 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
(In reply to Richard Earnshaw from comment #26)
> (In reply to Richard Biener from comment #25)
> > I think it's more interesting why
> >=20
> > * 119: [r216:SI (2 MEM[(struct Vec128<short int, 8> *)_179]+0 S4 A64)] =
=3D
> > {r0:SI..r3:SI}
> >=20
> > isn't considered as dependence?  Why does the earlier insn even come in=
to
> > play?  What's the breaking transform?  I guess insn 119 and 120 are
> > exchanged?
>=20
> Because 119 was deleted by postreload.  Doh! I should have spotted that.

But that ought to be ok, insn 115 is a store in alias set 0, so is picked u=
p by
later alias analysis.  It's just that the compiler then digs deeper and dec=
ides
that that isn't an addressable object (at the gimple level) so there can't
really be a dependency.=