From: Ian Lance Taylor <iant@google.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaud Lacombe <lacombar@gmail.com>,
gcc-help@gcc.gnu.org, stufever@gmail.com,
linux-kernel@vger.kernel.org,
Wang Shaoyan <wangshaoyan.pt@taobao.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] TRACING: Fix a copmile warning
Date: Mon, 25 Jul 2011 17:44:25 -0700 [thread overview]
Message-ID: <mcr7h75oopi.fsf@coign.corp.google.com> (raw)
In-Reply-To: <1311640534.3526.50.camel@gandalf.stny.rr.com> (Steven Rostedt's message of "Mon, 25 Jul 2011 20:35:34 -0400")
Steven Rostedt <rostedt@goodmis.org> writes:
>> It seems gcc transforms the conditional from:
>>
>> if (a != NULL && b != NULL) ...
>>
>> to
>>
>> if (b != NULL && a != NULL) ...
>>
>> In which case the warning is fully valid. I'm not sure what's the C
>> standard guarantee in term of conditional test order. gcc 4.7.0 has
>> the same behavior.
>
> Yes it seems to be doing this :-/
>
> This is a real bug!
To be clear, gcc is not doing that, and this is not a code generation
bug. It is a warning generation bug; the generated code is correct.
Ian
next prev parent reply other threads:[~2011-07-26 0:44 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-18 9:40 [PATCH] TRACING: Fix a copmile warning stufever
2011-07-25 18:32 ` Steven Rostedt
2011-07-25 19:43 ` Arnaud Lacombe
2011-07-25 20:19 ` Steven Rostedt
2011-07-25 20:28 ` Arnaud Lacombe
2011-07-25 22:38 ` Arnaud Lacombe
2011-07-25 23:49 ` Steven Rostedt
2011-07-25 23:52 ` Arnaud Lacombe
2011-07-26 0:14 ` Steven Rostedt
2011-07-25 23:50 ` Arnaud Lacombe
2011-07-25 23:58 ` Arnaud Lacombe
2011-07-26 0:08 ` Steven Rostedt
2011-07-26 0:35 ` Steven Rostedt
2011-07-26 0:44 ` Ian Lance Taylor [this message]
2011-07-26 0:41 ` Ian Lance Taylor
2011-07-26 1:08 ` Arnaud Lacombe
2011-07-26 1:12 ` Steven Rostedt
2011-07-26 1:19 ` Arnaud Lacombe
2011-07-26 20:43 ` Jeff Law
2011-07-26 1:10 ` Steven Rostedt
2011-07-26 5:55 ` Ian Lance Taylor
2011-07-26 12:00 ` Paulo Marques
2011-07-26 13:18 ` Jesper Juhl
2011-07-26 13:32 ` Paulo Marques
2011-07-26 13:55 ` Steven Rostedt
-- strict thread matches above, loose matches on Subject: below --
2011-07-18 9:35 stufever
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