Re: [PATCH] TRACING: Fix a copmile warning

From: Arnaud Lacombe
Date: Mon Jul 25 2011 - 19:52:35 EST


Hi,

On Mon, Jul 25, 2011 at 7:49 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Mon, 2011-07-25 at 18:38 -0400, Arnaud Lacombe wrote:
>> Hi,
>>
>> On Mon, Jul 25, 2011 at 4:19 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>> > On Mon, 2011-07-25 at 15:43 -0400, Arnaud Lacombe wrote:
>> >
>> >> Actually, we have a special uninitialized_var(x) macro to handle such
>> >> false positive. From include/linux/compiler-gcc.h:
>> >>
>> >> /*
>> >>  * A trick to suppress uninitialized variable warning without generating any
>> >>  * code
>> >>  */
>> >> #define uninitialized_var(x) x = x
>> >
>> > I'm aware of that too, but I think that is inappropriate as well. As I
>> > said, some versions of gcc report it, others don't. Seems that gcc 4.6.0
>> > says this is an error where 4.5.1 does not (I just tried both).
>> >
>> did you ? gcc 4.5.1 from Fedora 14 definitively shows the warning:
>
> Heh, I didn't use Fedora's version. I wonder if they added a patch or
> built it differently. I built my own 4.5.1 as well as my own 4.6.0.
>
I'd assume you're building with -O2, the warning only shows up at -Os,
see my previous mail.

- Arnaud
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