From: "Torsten Bögershausen" <tboegi@web.de>
To: Jeff King <peff@peff.net>
Cc: "Junio C Hamano" <gitster@pobox.com>,
git@vger.kernel.org, "Torsten Bögershausen" <tboegi@web.de>
Subject: Re: [PATCH 4/4] transport: drop "int cmp = cmp" hack
Date: Sun, 24 Mar 2013 15:54:36 +0100 [thread overview]
Message-ID: <514F13AC.6000100@web.de> (raw)
In-Reply-To: <20130324093212.GA28234@sigill.intra.peff.net>
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 ;-)
next prev parent reply other threads:[~2013-03-24 14:55 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-21 11:03 [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Jeff King
2013-03-21 11:05 ` [PATCH 1/4] wt-status: fix possible use of uninitialized variable Jeff King
2013-03-21 19:49 ` Jonathan Nieder
2013-03-21 19:55 ` Junio C Hamano
2013-03-21 19:58 ` Jonathan Nieder
2013-03-22 16:15 ` Jeff King
2013-03-21 11:08 ` [PATCH 2/4] fast-import: use pointer-to-pointer to keep list tail Jeff King
2013-03-21 20:43 ` Jonathan Nieder
2013-03-21 11:10 ` [PATCH 3/4] drop some obsolete "x = x" compiler warning hacks Jeff King
2013-03-21 15:16 ` Erik Faye-Lund
2013-03-21 20:47 ` Jonathan Nieder
2013-03-24 7:17 ` Torsten Bögershausen
2013-03-21 11:13 ` [PATCH 4/4] transport: drop "int cmp = cmp" hack Jeff King
2013-03-21 20:59 ` Jonathan Nieder
2013-03-24 4:00 ` Junio C Hamano
2013-03-24 9:32 ` Jeff King
2013-03-24 14:54 ` Torsten Bögershausen [this message]
2013-03-25 19:50 ` Junio C Hamano
2013-03-25 21:06 ` Jeff King
2013-03-25 21:55 ` Junio C Hamano
2013-03-21 11:45 ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Johannes Sixt
2013-03-21 11:55 ` Jeff King
2013-03-21 14:58 ` Junio C Hamano
2013-03-21 15:19 ` Junio C Hamano
2013-03-21 15:44 ` Jeff King
2013-03-21 15:44 ` [PATCH 5/4] fast-import: clarify "inline" logic in file_change_m Jeff King
2013-03-21 15:45 ` [PATCH 6/4] run-command: always set failed_errno in start_command Jeff King
2013-03-21 21:02 ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Jonathan Nieder
2013-03-22 16:18 ` Jeff King
2013-03-22 16:19 ` [PATCH 7/4] submodule: clarify logic in show_submodule_summary Jeff King
2013-03-22 21:10 ` Junio C Hamano
2013-03-22 16:21 ` [PATCH 8/4] match-trees: drop "x = x" initializations Jeff King
2013-03-22 21:26 ` Junio C Hamano
2013-03-22 21:33 ` Junio C Hamano
2013-03-22 21:36 ` Jeff King
2013-03-23 18:57 ` René Scharfe
2013-03-24 4:55 ` Junio C Hamano
2013-03-24 10:01 ` Jeff King
2013-03-24 22:46 ` René Scharfe
2013-03-25 16:10 ` Junio C Hamano
2013-03-21 13:44 ` [PATCH 0/4] drop some "int x = x" hacks to silence gcc warnings Joachim Schmitz
2013-03-21 13:56 ` Joachim Schmitz
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