Re: [PATCH 4/4] transport: drop "int cmp = cmp" hack

["Torsten Bögershausen" <tboegi@web.de>]

On 24.03.13 10:32, Jeff King wrote:
> On Sat, Mar 23, 2013 at 09:00:05PM -0700, Junio C Hamano wrote:
> 
>> On Thu, Mar 21, 2013 at 4:13 AM, Jeff King <peff@peff.net> wrote:
>>>
>>> According to 47ec794, this initialization is meant to
>>> squelch an erroneous uninitialized variable warning from gcc
>>> 4.0.1.  That version is quite old at this point, and gcc 4.1
>>> and up handle it fine, with one exception. There seems to be
>>> a regression in gcc 4.6.3, which produces the warning;
>>> however, gcc versions 4.4.7 and 4.7.2 do not.
>>>
>>
>> transport.c: In function 'get_refs_via_rsync':
>> transport.c:127:29: error: 'cmp' may be used uninitialized in this
>> function [-Werror=uninitialized]
>> transport.c:109:7: note: 'cmp' was declared here
>>
>> gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
> 
> Right, that's the same version I noted above. Is 4.6.3 the default
> compiler under a particular release of Ubuntu, or did you use their
> gcc-4.6 package?
> 
> -Peff
Side question:
How much does it hurt to write like this:

diff --git a/transport.c b/transport.c
index 6b2ae94..8020b62 100644
--- a/transport.c
+++ b/transport.c
@@ -106,7 +106,7 @@ static void insert_packed_refs(const char *packed_refs, struct ref **list)
                return;
 
        for (;;) {
-               int cmp, len;
+               int cmp=0, len;
 
==============

Using Ubuntu 10.4, using gcc (Ubuntu 4.4.3-4ubuntu5.1) 4.4.3
the compiler will add a line like this:

  2e83:	31 ff                	xor    %edi,%edi

(Which should not be to slow to execute)

Looking at a later gcc, from upcoming Debian, with gcc (Debian 4.7.2-5) 4.7.2
the assembly code is exactly the same ;-)