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From:   Florian Weimer <fweimer@redhat.com>
To:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc:     Segher Boessenkool <segher@kernel.crashing.org>,
        Will Deacon <will@kernel.org>, paulmck <paulmck@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        Andrea Parri <parri.andrea@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        David Howells <dhowells@redhat.com>,
        j alglave <j.alglave@ucl.ac.uk>,
        luc maranget <luc.maranget@inria.fr>,
        akiyks <akiyks@gmail.com>,
        linux-toolchains <linux-toolchains@vger.kernel.org>,
        linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [RFC PATCH] LKMM: Add ctrl_dep() macro for control dependency
References: <20210928211507.20335-1-mathieu.desnoyers@efficios.com>
        <87lf3f7eh6.fsf@oldenburg.str.redhat.com>
        <20210929174146.GF22689@gate.crashing.org>
        <2088260319.47978.1633104808220.JavaMail.zimbra@efficios.com>
Date:   Fri, 01 Oct 2021 18:26:11 +0200
In-Reply-To: <2088260319.47978.1633104808220.JavaMail.zimbra@efficios.com>
        (Mathieu Desnoyers's message of "Fri, 1 Oct 2021 12:13:28 -0400
        (EDT)")
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* Mathieu Desnoyers:

> One cheap way to achieve said R->W dependency (as well as R->RW on
> architectures which to not reorder R->R) is to ensure that the
> generated assembly contains a conditional branch.

Will any conditional branch do, or is it necessary that it depends in
some way on the data read?

Thanks,
Florian