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From: "manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/43772] Errant -Wlogical-op warning when testing limits
Date: Sat, 28 Apr 2012 13:08:00 -0000 [thread overview]
Message-ID: <bug-43772-4-Nb5i1J3lbs@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-43772-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43772
--- Comment #16 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-28 13:07:41 UTC ---
(In reply to comment #15)
>
> No, there could be a warning that the first test is always false, another one
> that the second one is always false, but adding a third warning that the
> conjunction of the 2 is always false seems bogus. This warning is meant for:
> x<5&&x>10, where each test independently could be true, just not both at the
> same time.
I understand now, and I think you are right. We don't have a warning for
"((int)x) < INT_MIN" or ((int)x) > INT_MAX but I think it should go to
Wtype-limits.
Do you think we could test this situation just before the Wlogical-op warning?
I can see that some macros may generate x >= INT_MIN but the x < INT_MIN case
seems less likely to be intented and we should warn (and then return and avoid
warning with Wlogical-op).
I am sure there must be a way to test for "x < MIN_OF_TYPE_OF(x))" and "x >
MAX_OF_TYPE_OF(x)" I just haven't investigated how.
next prev parent reply other threads:[~2012-04-28 13:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-43772-4@http.gcc.gnu.org/bugzilla/>
2011-06-15 19:20 ` eggert at gnu dot org
2011-07-15 3:02 ` eggert at gnu dot org
2012-04-28 12:20 ` marc.glisse at normalesup dot org
2012-04-28 12:33 ` manu at gcc dot gnu.org
2012-04-28 12:34 ` marc.glisse at normalesup dot org
2012-04-28 12:38 ` manu at gcc dot gnu.org
2012-04-28 12:40 ` marc.glisse at normalesup dot org
2012-04-28 12:50 ` manu at gcc dot gnu.org
2012-04-28 12:56 ` marc.glisse at normalesup dot org
2012-04-28 13:08 ` manu at gcc dot gnu.org [this message]
2012-04-28 18:50 ` marc.glisse at normalesup dot org
2012-04-28 21:53 ` eggert at gnu dot org
2012-04-28 22:17 ` marc.glisse at normalesup dot org
2012-04-28 22:41 ` eggert at gnu dot org
2012-05-05 11:32 ` manu at gcc dot gnu.org
2012-05-05 12:15 ` manu at gcc dot gnu.org
2014-06-10 23:19 ` P at draigBrady dot com
2010-04-16 21:44 [Bug c/43772] New: " P at draigBrady dot com
2010-04-17 11:03 ` [Bug c/43772] " rguenth at gcc dot gnu dot org
2010-04-17 17:41 ` P at draigBrady dot com
2010-04-22 0:38 ` P at draigBrady dot com
2010-09-23 6:52 ` muntyan at fastmail dot fm
2010-09-23 8:13 ` manu at gcc dot gnu dot org
2010-09-23 8:24 ` manu at gcc dot gnu dot org
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