From: Andi Kleen <andi@firstfloor.org>
To: Mikael Pettersson <mikpe@it.uu.se>
Cc: Roel Kluin <roel.kluin@gmail.com>,
Andi Kleen <andi@firstfloor.org>,
"David S. Miller" <davem@davemloft.net>,
penberg@cs.helsinki.fi, Brian Gerst <brgerst@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-crypto@vger.kernel.org, Herbert@gondor.apana.org.au
Subject: Re: [PATCH v2] compiler: prevent dead store elimination
Date: Tue, 2 Mar 2010 13:17:02 +0100 [thread overview]
Message-ID: <20100302121701.GA19208@basil.fritz.box> (raw)
In-Reply-To: <19339.35080.637800.292674@pilspetsen.it.uu.se>
> > + do { \
> > + struct __scrub { typeof(*p) c[n]; }; \
>
> The typeof(*p) suggestion doesn't work. It would require p to always be
> a pointer type with an accurate (for memset) sizeof(*p). In general however
> we'll memset some array described by a void*/size_t pair, and typeof in
> that case is useless. The original'struct __scrub { char c[n]; };' was Ok.
I just suggested it because of the original array name of the macro
and without it it would have only worked for char arrays. With the new
naming it's ok I guess.
It could be made to work with macros and builtin_type_match I guess,
but it would be fairly ugly and not worth it.
-Andi
next prev parent reply other threads:[~2010-03-02 12:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-27 20:47 [PATCH v1] compiler: prevent dead store elimination Roel Kluin
2010-02-28 9:55 ` Andi Kleen
2010-02-28 15:34 ` [PATCH v2] " Roel Kluin
2010-03-01 9:29 ` Mikael Pettersson
2010-03-02 12:17 ` Andi Kleen [this message]
2010-03-03 23:16 ` [PATCH v3] " Roel Kluin
2010-03-02 12:24 ` [PATCH v2] " Andi Kleen
2010-03-01 0:36 ` [PATCH v1] " Bill Davidsen
2010-03-01 5:15 ` Arjan van de Ven
2010-03-01 9:32 ` Mikael Pettersson
2010-03-01 9:33 ` Alexey Dobriyan
2010-03-01 22:27 ` Andi Kleen
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