From: Roland Dreier <rdreier@cisco.com>
To: "Satyam Sharma" <satyam.sharma@gmail.com>
Cc: linux-kernel@vger.kernel.org, openib-general@openib.org
Subject: Re: [ofa-general] Re: dealing with gcc 'comparison is always false' warnings
Date: Wed, 30 May 2007 08:56:37 -0700 [thread overview]
Message-ID: <adaveeaqp8q.fsf@cisco.com> (raw)
In-Reply-To: <a781481a0705300841k2a02335eg66985129eaed28f4@mail.gmail.com> (Satyam Sharma's message of "Wed, 30 May 2007 21:11:29 +0530")
> However, gcc is _just as correct_. It is only crying about seeing a condition
> that the programmer could have written with some purpose in mind but which
> is being completely compiled away by it when generating the code because
> of it being a tautology / contradiction ...
Well, OK, but there's lots of things gcc could warn about. How about
while (1) { ...
By your argument gcc should warn that '1' always evaluates to true.
Or how about
#if 0
why shouldn't the preprocessor warn that the conditional is always false?
> No, shutting gcc up wouldn't be the right thing, IMHO. These warnings are
> a good reminder to the programmer to go and see if there is a real bug
> somewhere and if something really needs to be done with the code (could
> be simply to change the type of a variable to signed that was mistakenly
> declared unsigned, f.e.).
OK, but suppose I looked at it and there's no bug. Leaving the
warning has a cost too: it hides useful warnings (that might be
showing real bugs) in all the clutter.
- R.
next prev parent reply other threads:[~2007-05-30 15:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-30 8:05 [PATCH] drivers/infiniband: fix comparsion between unsigned and negative Bill Nottingham
2007-05-30 15:30 ` dealing with gcc 'comparison is always false' warnings (was: [PATCH] drivers/infiniband: fix comparsion between unsigned and negative) Roland Dreier
2007-05-30 15:41 ` Satyam Sharma
2007-05-30 15:56 ` Roland Dreier [this message]
2007-05-30 17:00 ` [ofa-general] Re: dealing with gcc 'comparison is always false' warnings Satyam Sharma
2007-05-30 16:06 ` dealing with gcc 'comparison is always false' warnings (was: [PATCH] drivers/infiniband: fix comparsion between unsigned and negative) Satyam Sharma
2007-05-30 19:00 ` dealing with gcc 'comparison is always false' warnings Tilman Schmidt
2007-05-30 19:14 ` Satyam Sharma
2007-05-30 19:09 ` dealing with gcc 'comparison is always false' warnings (was: [PATCH] drivers/infiniband: fix comparsion between unsigned and negative) Bill Nottingham
2007-05-30 19:23 ` Satyam Sharma
2007-05-30 20:48 ` [ofa-general] [PATCH] drivers/infiniband: fix comparsion between unsigned and negative Roland Dreier
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