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 D08913858D20; Mon, 26 Jun 2023 07:58:16 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D08913858D20
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1687766296;
	bh=ZKOBbDnFJy7pLYtE4cccm7Y/FWL1vfxzQWoK2AFZdO0=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=nIfRB/02Wq8JsjNrdCclons7SZJ+ydFcTXRcWcoT8wDo97PlUHxombJBNv89KGwPH
	 GKt/+2KxBCJOZ90EFL5ObRkhN7dQqNU9fK4deriYcckEA6K2TI6/8I06I3g3rlgdh6
	 m82houcb9ulrk+7VFixo2JsBGhlcIlsnh4d6uU7w=
From: "amonakov at gcc dot gnu.org" <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: Mon, 26 Jun 2023 07:58:16 +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: amonakov at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-110237-4-GDO58DPZK8@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 #11 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
The trapping angle seems valid, but I have a really hard time understanding=
 the
DSE issue, and the preceding issue about disambiguation based on RTL aliasi=
ng.

How would DSE optimize out 'd[5] =3D 1' in your example when the mask_store=
 reads
it? Isn't that a data dependency?

How is the initial issue different from

int f(__m128i *p, __m128i v, int *q)
{
  *q =3D 0;
  *p =3D v;
  return *q;
}

that we cannot optimize to 'return 0' due to __attribute__((may_alias))
attached to __m128i?=