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From: "marc.glisse at normalesup dot 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 22:17:00 -0000 [thread overview] Message-ID: <bug-43772-4-1b6oq1rMYR@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 #19 from Marc Glisse <marc.glisse at normalesup dot org> 2012-04-28 22:16:55 UTC --- (In reply to comment #18) > I'm afraid that false positives would still be likely. > For example, suppose we're on a platform where > INT_MAX = LONG_MAX < INTMAX_MAX. Then: > > intmax_t i = (whatever); > if (INT_MAX < i && i <= LONG_MAX) > print ("i is in 'long' but not 'int' range"); Have you actually seen that? I would imagine the following to be more common: if(i<=INT_MAX) print("i is in 'int'"); else if(i<=LONG_MAX) ... > This sort of thing is fairly common in portable code, > and GCC shouldn't warn about it merely because > we're on a platform where the two tests cannot both > be true when INT_MAX == LONG_MAX. Well, can you define a set of circumstances where gcc could / should warn? a<i&&i<=a seems to be quite precisely what this warning is about. Or maybe a==INT_MAX (adapt depending on the type) should disable the warning, as a special case? Please also remember that we are not talking of having this warning by default, this is an isolated warning not even included in -Wall -Wextra.
next prev parent reply other threads:[~2012-04-28 22:17 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 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 [this message] 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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