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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/53645] Missed optimization for division of vector types
Date: Tue, 12 Jun 2012 13:34:00 -0000	[thread overview]
Message-ID: <bug-53645-4-a9h99IZxmD@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53645-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53645

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-06-12
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-12 13:34:21 UTC ---
The issue is that no packed integer division exists and that we lower the
vector division to scalar code:

<bb 2>:
  D.2165_4 = BIT_FIELD_REF <x_1(D), 32, 0>;
  D.2166_5 = D.2165_4 / 3;
  D.2167_6 = BIT_FIELD_REF <x_1(D), 32, 32>;
  D.2168_7 = D.2167_6 / 3;
  D.2169_8 = BIT_FIELD_REF <x_1(D), 32, 64>;
  D.2170_9 = D.2169_8 / 3;
  D.2171_10 = BIT_FIELD_REF <x_1(D), 32, 96>;
  D.2172_11 = D.2171_10 / 3;
  D.2159_2 = {D.2166_5, D.2168_7, D.2170_9, D.2172_11};

this lowering should instead try to do the multiplication trick.

Compilable testcase:

typedef int v4si __attribute__((vector_size(16)));
v4si ttt(v4si x) 
{
    return x / (v4si) {3,3,3,3};
}


  reply	other threads:[~2012-06-12 13:34 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-12 12:45 [Bug c/53645] New: " andrii.riabushenko at barclays dot com
2012-06-12 13:34 ` rguenth at gcc dot gnu.org [this message]
2012-06-12 13:37 ` [Bug tree-optimization/53645] Missed optimization for vector integer division lowering rguenth at gcc dot gnu.org
2012-06-12 18:34 ` jakub at gcc dot gnu.org
2012-06-12 20:55 ` pinskia at gcc dot gnu.org
2012-06-13  9:46 ` rguenth at gcc dot gnu.org
2012-06-27  8:50 ` jakub at gcc dot gnu.org
2012-06-28 11:38 ` jakub at gcc dot gnu.org
2012-06-28 12:34 ` jakub at gcc dot gnu.org
2012-06-28 17:53 ` jakub at gcc dot gnu.org
2012-07-01 10:24 ` ubizjak at gmail dot com
2012-07-02  6:56 ` jakub at gcc dot gnu.org
2012-07-02  7:00 ` jakub at gcc dot gnu.org

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