From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Murray <murrayie@yahoo.co.uk>
Subject: Re: [PATCH 1/1] hvm.c: Prevent gcc uninitialised
	var	warning
Date: Thu, 26 Mar 2015 11:15:33 +0000 (UTC)
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To: Jan Beulich <JBeulich@suse.com>, Don Slutz <dslutz@verizon.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Keir Fraser <keir@xen.org>, Ian Campbell <ian.campbell@citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
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----- Original Message -----
> From: Jan Beulich <JBeulich@suse.com>
> To: Don Slutz <dslutz@verizon.com>
> Cc: Ian Murray <murrayie@yahoo.co.uk>; Andrew Cooper <andrew.cooper3@citrix.com>; Keir Fraser <keir@xen.org>; Ian Campbell <ian.campbell@citrix.com>; xen-devel@lists.xen.org
> Sent: Thursday, 26 March 2015, 7:48
> Subject: Re: [Xen-devel] [PATCH 1/1] hvm.c: Prevent gcc uninitialised var	warning
> 
>>>>  On 25.03.15 at 21:03, <dslutz@verizon.com> wrote:
>>  On 03/25/15 11:48, Jan Beulich wrote:
>>>>>>  On 25.03.15 at 16:02, <andrew.cooper3@citrix.com> 
> wrote:
>>>>  As an aside, the compiler is in a very easy position to spot this.  
> The
>>>>  error means that GCC has positively identified a basic block which 
> does
>>>>  use bufioreq_pfn before it has been initialised.
>>>> 
>> 
>>  If the compiler is right, how come the messages says:
>> 
>>  may be used
>> 
>>  which to me says that it's determination is not 100%
> 
> No, that's a wrong interpretation of the wording - it instead means
> that there is at least one path where the variable gets initialized,
> and at least one where that's not provably the case. As opposed
> to a variable being used uninitialized no matter what path leads to
> the use site.

> 


FWIW, I upgraded one of the boxes with the issue to Ubuntu 14.04.2 and gcc no longer complained.


# gcc --version
gcc-4.8.real (Ubuntu 4.8.2-19ubuntu1) 4.8.2



> 
> Jan
> 
> 
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