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From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/31605] [4.2/4.3 Regression] VRP eliminates a useful test due with conversion from unsigned int to int
Date: Tue, 17 Apr 2007 19:28:00 -0000 [thread overview]
Message-ID: <20070417192745.16603.qmail@sourceware.org> (raw)
In-Reply-To: <bug-31605-3264@http.gcc.gnu.org/bugzilla/>
------- Comment #4 from pinskia at gcc dot gnu dot org 2007-04-17 20:27 -------
And it is a bug on the 4.2 branch.
Before Ian's patch we got the following ranges for the testcase in comment #2:
D.1528_1: VARYING
start_2: VARYING
D.1528_3: VARYING
cur_bitshift_4: ~[0, 0] EQUIVALENCES: { } (0 elements)
start_5: [0, 0fffffff8] EQUIVALENCES: { start_2 } (1 elements)
<retval>_6: VARYING
start_9: [0fffffff9, +INF] EQUIVALENCES: { start_2 } (1 elements)
After we get:
D.1528_1: VARYING
start_2: VARYING
D.1528_3: VARYING
cur_bitshift_4: [-INF(OVF), -2147483648] EQUIVALENCES: { } (0 elements)
start_5: [0, 0fffffff8] EQUIVALENCES: { start_2 } (1 elements)
<retval>_6: VARYING
start_9: [0fffffff9, +INF] EQUIVALENCES: { start_2 } (1 elements)
Before:
Visiting statement:
cur_bitshift_4 = (int) start_9;
Found new range for cur_bitshift_4: ~[0, 0]
After:
Visiting statement:
cur_bitshift_4 = (int) start_9;
Found new range for cur_bitshift_4: [-INF(OVF), -2147483648]
That is just incorrect.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.3 Regression] VRP |[4.2/4.3 Regression] VRP
|eliminates a useful test due|eliminates a useful test due
|with conversion from |with conversion from
|unsigned int to int |unsigned int to int
Target Milestone|4.3.0 |4.2.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31605
next prev parent reply other threads:[~2007-04-17 19:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-17 13:49 [Bug tree-optimization/31605] New: VRP eliminates a useful test due to overflow drow at gcc dot gnu dot org
2007-04-17 14:15 ` [Bug tree-optimization/31605] [4.3 Regression] VRP eliminates a useful test due with conversion from unsigned int to int pinskia at gcc dot gnu dot org
2007-04-17 14:28 ` pinskia at gcc dot gnu dot org
2007-04-17 19:20 ` pinskia at gcc dot gnu dot org
2007-04-17 19:28 ` pinskia at gcc dot gnu dot org [this message]
2007-04-21 1:08 ` [Bug tree-optimization/31605] [4.2/4.3 " ian at airs dot com
2007-04-24 20:38 ` mmitchel at gcc dot gnu dot org
2007-04-24 22:24 ` ian at gcc dot gnu dot org
2007-04-24 22:26 ` ian at gcc dot gnu dot org
2007-04-24 22:28 ` ian at airs dot com
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