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From: "vda dot linux at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/28632] VRP should understand bitwise OR and AND
Date: Mon, 04 Aug 2008 11:29:00 -0000	[thread overview]
Message-ID: <20080804112827.20128.qmail@sourceware.org> (raw)
In-Reply-To: <bug-28632-12956@http.gcc.gnu.org/bugzilla/>



------- Comment #8 from vda dot linux at googlemail dot com  2008-08-04 11:28 -------
Created an attachment (id=16010)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16010&action=view)
Example program which is compiled differently with this patch.

The difference is here:

        movl    (%edx), %eax    #,
        call    bb_simple_perror_msg    #
 .L40:
-       orl     $1, 12(%esp)    #, errs
+       movl    $1, 12(%esp)    #, errs
 .L19:
        addl    $4, 24(%esp)    #, argv.78
        movl    24(%esp), %eax  # argv.78,

With improved VRP on (a | b), gcc now can deduce that in this program, errs |=
1 is always equivalent to errs = 1.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28632


  parent reply	other threads:[~2008-08-04 11:29 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-07 11:12 [Bug tree-optimization/28632] New: [PATCH] add VRP for " vda dot linux at googlemail dot com
2006-08-07 11:13 ` [Bug tree-optimization/28632] " vda dot linux at googlemail dot com
2006-08-07 11:14 ` vda dot linux at googlemail dot com
2006-08-07 11:26 ` vda dot linux at googlemail dot com
2006-08-07 14:54 ` pinskia at gcc dot gnu dot org
2006-08-08  0:37 ` [Bug tree-optimization/28632] VRP should understand " pinskia at gcc dot gnu dot org
2006-08-08  0:37 ` pinskia at gcc dot gnu dot org
2006-08-11 14:17 ` vda dot linux at googlemail dot com
2008-08-04 11:27 ` vda dot linux at googlemail dot com
2008-08-04 11:29 ` vda dot linux at googlemail dot com [this message]
2008-08-04 11:36 ` vda dot linux at googlemail dot com
2008-08-04 11:56 ` vda dot linux at googlemail dot com
2008-08-11 12:47 ` vda dot linux at googlemail dot com
2008-08-18 13:04 ` vda dot linux at googlemail dot com
2008-08-20 14:58 ` vda dot linux at googlemail dot com
2008-08-20 14:59 ` vda dot linux at googlemail dot com
2008-08-20 15:08 ` vda dot linux at googlemail dot com
2009-06-05 16:27 ` aldot at gcc dot gnu dot org
2009-06-10 16:48 ` aldot at gcc dot gnu dot org
2009-06-22  8:29 ` aldot at gcc dot gnu dot org
2010-01-02  1:00 ` steven at gcc dot gnu dot org
2010-07-09  7:53 ` aldot at gcc dot gnu dot org
2010-07-09  8:10 ` aldot at gcc dot gnu dot org
2010-07-09 17:12 ` jakub at gcc dot gnu dot org
2010-07-09 19:40 ` jakub at gcc dot gnu dot org
     [not found] <bug-28632-4@http.gcc.gnu.org/bugzilla/>
2010-09-24 11:36 ` jakub at gcc dot gnu.org

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