From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-204442-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 4349 invoked by alias); 7 Dec 2006 18:18:22 -0000
Received: (qmail 4272 invoked by uid 48); 7 Dec 2006 18:18:09 -0000
Date: Thu, 07 Dec 2006 18:18:00 -0000
Message-ID: <20061207181809.4271.qmail@sourceware.org>
X-Bugzilla-Reason: CC
References: <bug-30105-1008@http.gcc.gnu.org/bugzilla/>
Subject: [Bug tree-optimization/30105] missed PRE (add)
In-Reply-To: <bug-30105-1008@http.gcc.gnu.org/bugzilla/>
Reply-To: gcc-bugzilla@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org
From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2006-12/txt/msg00627.txt.bz2



------- Comment #2 from pinskia at gcc dot gnu dot org  2006-12-07 18:18 -------
Actually this is a PRE opertunity.
if we look into .102t.final_cleanup, we notice we did the load PRE:
<L2>:;
  prephitmp.32 = *data;
  prephitmp.38 = *(data + 12B);
  i = 1;
  goto <bb 5> (<L1>);

<L0>:;
  *((int *) ((unsigned int) *(data + 8B) * 4) + data) = 2;
  prephitmp.32 = *data;
  prephitmp.38 = *(data + 12B);
  i = prephitmp.32 + 1 + prephitmp.38;

<L1>:;
  *(data + 16B) = prephitmp.38 + prephitmp.32;

but did not do the other part of the pre for the add.
I think this is a reassiocation issue:
<L0>:
  ...
  j_15 = D.1620_12 + 1;
  i_16 = j_15 + D.1622_14;

  # prephitmp.32_37 = PHI <pretmp.31_36(5), D.1622_14(3)>;
  # prephitmp.32_35 = PHI <pretmp.31_34(5), D.1620_12(3)>;
  # prephitmp.30_33 = PHI <pretmp.29_32(5), D.1621_13(3)>;
  # i_1 = PHI <1(5), i_16(3)>;
<L1>:;
....
  D.1620_18 = prephitmp.32_35;
  D.1621_19 = prephitmp.30_33;
  D.1622_20 = prephitmp.32_37;
  D.1624_21 = D.1622_20 + D.1620_18;


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|missed code hoisting        |missed PRE (add)


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30105