From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH 2/8] KVM: x86: cleanup kvm_apic_match_*()
Date: Mon, 2 Feb 2015 15:30:54 +0100
Message-ID: <20150202143054.GC19731@potion.redhat.com>
References: <1422568135-28402-1-git-send-email-rkrcmar@redhat.com>
 <1422568135-28402-3-git-send-email-rkrcmar@redhat.com>
 <54CB4668.30909@redhat.com>
 <20150202142633.GA19731@potion.redhat.com>
 <54CF8993.7060901@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Nadav Amit <namit@cs.technion.ac.il>,
	Gleb Natapov <gleb@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <54CF8993.7060901@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

2015-02-02 15:28+0100, Paolo Bonzini:
>=20
>=20
> On 02/02/2015 15:26, Radim Kr=C4=8Dm=C3=A1=C5=99 wrote:
> >>> > > +		return ((logical_id >> 4) =3D=3D (mda >> 4))
> >>> > > +		       && (logical_id & mda & 0xf);
> > was merged as
> >=20
> > +		return ((logical_id >> 4) =3D=3D (mda >> 4))
> > +		       && (logical_id & mda & 0xf) !=3D 0;
> >=20
> > but it has to be parenthesized ('&&' has lower precedence than '!=3D=
').
>=20
> Lower precedence means that the merged version is right (unless my br=
ain
> went bonkers, which I cannot exclude).  "!=3D" has higher precedence =
and
> thus it is implicitly parenthesized.
>=20
> In fact the first comparison could have its parentheses removed as we=
ll.

Yes, it could be,
  logical_id >> 4 =3D=3D mda >> 4 && (logical_id & mda & 0xf) !=3D 0

I missed the point and thought that you wanted to turn the whole
expression into bool, when it already was one.