From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-127749-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 32607 invoked by alias); 23 Jan 2005 01:43:27 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
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
Received: (qmail 32531 invoked by uid 48); 23 Jan 2005 01:43:23 -0000
Date: Sun, 23 Jan 2005 01:43:00 -0000
From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20050123014322.19581.pinskia@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug tree-optimization/19581] New: Missed store monition on the tree level (on PPC in general)
X-Bugzilla-Reason: CC
X-SW-Source: 2005-01/txt/msg03230.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

This is like PR 19580 but a request to optimize it on the tree level instead of just on the RTL level.  
Mainly because we don't catch it for PPC (with 3.3.3 or with -fno-gcse).
int r[6];

void f (int n)
{
  while (-- n)
    {
      r [0] += r [5];
      r [1] += r [0];
      r [2] += r [1];
      r [3] += r [2];
      r [4] += r [3];
      r [5] += r [4];
    }
}

We should be able to pull out the load and stores for r[0] ... r[5].
If we do it on the tree level, we also just fix the problem for 4.0 also (but I think this might need more 
aliasing analysis or I could be wrong).

-- 
           Summary: Missed store monition on the tree level (on PPC in
                    general)
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, alias, TREE
          Severity: enhancement
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19581