From: Arnd Bergmann <arnd@arndb.de>
To: Tomas Winkler <tomasw@gmail.com>
Cc: "Levy, Amir (Jer)" <amir.jer.levy@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
"mm-commits@vger.kernel.org" <mm-commits@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"jpoimboe@redhat.com" <jpoimboe@redhat.com>,
Martin Jambor <mjambor@suse.cz>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Denys Vlasenko <dvlasenk@redhat.com>, Thomas Graf <tgraf@suug.ch>,
Peter Zijlstra <peterz@infradead.org>,
David Rientjes <rientjes@google.com>,
Ingo Molnar <mingo@kernel.org>,
Himanshu Madhani <himanshu.madhani@qlogic.com>,
Dept-Eng QLA2xxx Upstream <qla2xxx-upstream@qlogic.com>,
Jan Hubicka <hubicka@ucw.cz>
Subject: Re: [PATCH v2] byteswap: try to avoid __builtin_constant_p gcc bug
Date: Wed, 22 Jun 2016 14:25:11 +0200 [thread overview]
Message-ID: <7892604.CjmUVh55Wd@wuerfel> (raw)
In-Reply-To: <CA+i0qc4TO=ucHUJduwGTAhU9Uzy0aTk-75N3uQ9piWZWKKUBFA@mail.gmail.com>
On Wednesday, June 22, 2016 2:44:21 PM CEST Tomas Winkler wrote:
> >
> > There are more than 20 files that have the statement: case cpu_to_...
> > Sparse complains about: case __builtin_bswap, not about __builtin_constant_p.
>
> There is even much more in the header files used in initializers,
> which also require constants. I wonder if __builtin_bswap produces
> constant expression correctly under gcc?
In gcc-4.8 or later yes. gcc-4.6/4.7 on powerpc was a special case that we
have worked around now, as the 16-bit byteswap there was not a constant
expression, unlike the 32-bit and 64-bit ones.
Arnd
next prev parent reply other threads:[~2016-06-22 12:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-02 21:48 [PATCH v2] byteswap: try to avoid __builtin_constant_p gcc bug Arnd Bergmann
2016-05-02 23:02 ` Andrew Morton
2016-05-02 23:10 ` Arnd Bergmann
2016-05-02 23:32 ` Andrew Morton
2016-05-02 23:32 ` Andrew Morton
2016-05-03 6:36 ` Arnd Bergmann
2016-06-21 9:02 ` Tomas Winkler
2016-06-21 9:02 ` Tomas Winkler
2016-06-22 8:24 ` Tomas Winkler
2016-06-22 8:24 ` Tomas Winkler
2016-06-22 9:59 ` Arnd Bergmann
2016-06-22 10:25 ` Levy, Amir (Jer)
2016-06-22 11:44 ` Tomas Winkler
2016-06-22 12:25 ` Arnd Bergmann [this message]
2016-06-23 6:27 ` Tomas Winkler
2016-06-23 9:29 ` Arnd Bergmann
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