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From: "burnus at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/41137] inefficient zeroing of an array
Date: Mon, 21 Jun 2010 15:22:00 -0000	[thread overview]
Message-ID: <20100621152219.27770.qmail@sourceware.org> (raw)
In-Reply-To: <bug-41137-6642@http.gcc.gnu.org/bugzilla/>



------- Comment #8 from burnus at gcc dot gnu dot org  2010-06-21 15:22 -------
(In reply to comment #7)
> I get for the example the following values, note especially the newly added
> CONTIGUOUS result:

For the test case, see attachment 20966 at PR 44612; that PR I have filled
because GCC does not optimize away the loops, which only set but never read the
value from the variable. (Ifort does this optimization.) Additionally, if one
prints the variable, ifort is twice as fast. For curiosity: Using NAG, the
timing is 0.6900000 vs. 1.2200000, i.e. the assumed-shape version is actually
faster [though, its overall the performance is poor].


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41137


  parent reply	other threads:[~2010-06-21 15:22 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-21  6:15 [Bug fortran/41137] New: " jv244 at cam dot ac dot uk
2009-08-21  7:02 ` [Bug fortran/41137] " jv244 at cam dot ac dot uk
2009-08-21  7:40 ` dfranke at gcc dot gnu dot org
2009-08-21  8:29 ` jv244 at cam dot ac dot uk
2009-08-24 20:06 ` jv244 at cam dot ac dot uk
2009-11-01 16:21 ` tkoenig at gcc dot gnu dot org
2009-11-01 17:36 ` tkoenig at gcc dot gnu dot org
2010-05-07 21:02 ` dfranke at gcc dot gnu dot org
2010-06-21 15:02 ` burnus at gcc dot gnu dot org
2010-06-21 15:22 ` burnus at gcc dot gnu dot org [this message]
2010-06-21 15:49 ` jv244 at cam dot ac dot uk
2010-06-21 17:00 ` burnus at gcc dot gnu dot org
2010-06-21 17:44 ` jakub at gcc dot gnu dot org
2010-06-22 14:42 ` burnus at gcc dot gnu dot org
2010-06-22 15:25 ` jakub at gcc dot gnu dot org
     [not found] <bug-41137-4@http.gcc.gnu.org/bugzilla/>
2013-03-29  9:47 ` Joost.VandeVondele at mat dot ethz.ch
2013-03-29 22:19 ` tkoenig at gcc dot gnu.org
2013-03-29 22:39 ` burnus at gcc dot gnu.org
2014-05-01 12:16 ` dominiq at lps dot ens.fr
2014-05-01 12:35 ` Joost.VandeVondele at mat dot ethz.ch
2014-05-01 17:00 ` tkoenig at gcc dot gnu.org

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