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Re: [PATCH, tree-ssa] Avoid -Wuninitialized warning in try_unroll_loop_completely()
- From: Chung-Ju Wu <jasonwucj at gmail dot com>
- To: Jeff Law <law at redhat dot com>
- Cc: gcc patches <gcc-patches at gcc dot gnu dot org>, dnovillo at google dot com, amacleod at redhat dot com
- Date: Thu, 18 Apr 2013 18:16:19 +0800
- Subject: Re: [PATCH, tree-ssa] Avoid -Wuninitialized warning in try_unroll_loop_completely()
- References: <CADj25HPE6ZVONBykpxC2tE0pYOx28=j9H+5cpt8ds2=jma63Wg at mail dot gmail dot com> <516C0943 dot 5080400 at redhat dot com> <CADj25HOHjO54d6+fmdawjz+2j1VOn0aWarW3EAX03VFgCNcgrA at mail dot gmail dot com> <516F04BA dot 3070803 at redhat dot com>
2013/4/18 Jeff Law <firstname.lastname@example.org>:
> On 04/15/2013 08:35 PM, Chung-Ju Wu wrote:
>> I was using gcc-4.6.3, which is provided by Ubuntu 12.04,
>> and the warning is displayed during the compilation process.
>> As I tried to build another native gcc by myself with
>> current main trunk and used it to compile tree-ssa-loop-ivcanon.c again,
>> there is no such warning at all.
>> (See attachment for my console output.)
>> So I am wondering if my patch is still valuable since
>> such false positive warning is already fixed on trunk.
> Thanks for checking on this stuff. My preference would be to not add the
> initialization unless we're currently seeing false positive warnings with
> the trunk.
> Anytime we add a dummy initialization like this to avoid a false positive,
> we run the risk of missing real bugs later if the nearby code is changed in
> such a way as to expose an uninitialized use, which we'd like to catch, but
> can't if we're inserted a dummy initialization.
I see. Leaving it unchanged indeed helps to catch possible bug
when nearby code is modified.
I will not commit this patch.
Thanks for the review and I did learn a lot from it! :)