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From: "irar at il dot ibm dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/37573] [4.4 Regression] gcc-4.4 regression: incorrect code generation with -O1 -ftree-vectorize
Date: Sun, 21 Sep 2008 07:56:00 -0000 [thread overview]
Message-ID: <20080921075440.3579.qmail@sourceware.org> (raw)
In-Reply-To: <bug-37573-15165@http.gcc.gnu.org/bugzilla/>
------- Comment #6 from irar at il dot ibm dot com 2008-09-21 07:54 -------
(In reply to comment #5)
> The data dependence on the previous loop is clearly not considered, the loop is
> vectorized as if c on the rhs and c on the lhs were different non-overlapping
> arrays.
>
The data dependence analysis returns chrec_known for that ddr (probably getting
confused by *&s.c[0] and *&s.c[1] base objects), so the vectorizer thinks they
are independent and vectorizes the loop.
*D.1659_13
base_address: &s.c[0]
offset from base address: 0
constant offset from base address: 0
step: 4
aligned to: 128
base_object: *&s.c[0]
symbol tag: SMT.62
*D.1655_9
base_address: &s.c[1]
offset from base address: 0
constant offset from base address: 0
step: 4
aligned to: 128
base_object: *&s.c[1]
symbol tag: SMT.62
(compute_affine_dependence
(stmt_a =
D.1660_14 = *D.1659_13;
)
(stmt_b =
*D.1655_9 = D.1664_23;
)
)
--
irar at il dot ibm dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rakdver at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37573
next prev parent reply other threads:[~2008-09-21 7:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-18 17:31 [Bug tree-optimization/37573] New: " edwintorok at gmail dot com
2008-09-18 17:31 ` [Bug tree-optimization/37573] " edwintorok at gmail dot com
2008-09-18 17:33 ` edwintorok at gmail dot com
2008-09-18 19:15 ` [Bug tree-optimization/37573] [4.4 Regression] " pinskia at gcc dot gnu dot org
2008-09-19 17:03 ` jakub at gcc dot gnu dot org
2008-09-19 17:53 ` jakub at gcc dot gnu dot org
2008-09-21 7:56 ` irar at il dot ibm dot com [this message]
2008-10-15 21:30 ` spop at gcc dot gnu dot org
2008-10-15 21:46 ` rguenth at gcc dot gnu dot org
2008-10-15 21:49 ` rguenth at gcc dot gnu dot org
2008-10-16 0:03 ` spop at gcc dot gnu dot org
2008-10-16 8:16 ` rguenther at suse dot de
2008-10-22 16:10 ` Sebastian Pop
2008-10-22 3:29 ` mmitchel at gcc dot gnu dot org
2008-10-22 16:11 ` sebpop at gmail dot com
2008-10-29 18:49 ` edwintorok at gmail dot com
2008-11-03 9:56 ` rguenth at gcc dot gnu dot org
2008-11-03 12:34 ` rguenth at gcc dot gnu dot org
2008-11-03 12:35 ` rguenth at gcc dot gnu dot org
2008-11-03 17:52 ` edwintorok at gmail dot com
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