From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-218491-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 19478 invoked by alias); 17 May 2007 22:49:19 -0000
Received: (qmail 19440 invoked by uid 48); 17 May 2007 22:49:06 -0000
Date: Thu, 17 May 2007 22:49:00 -0000
Subject: [Bug tree-optimization/31981]  New: Missed forw prop with indirect ref and addr.
X-Bugzilla-Reason: CC
Message-ID: <bug-31981-6528@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: 2007-05/txt/msg01356.txt.bz2

This testcase should pass:
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-forwprop" }  */

/* We should be able to optimize this to b.t[i] = 1 during
   early optimizations.  */

struct a
{
  int t[10];
};

struct a b;

void f(__SIZE_TYPE__ i)
{
  int *c = b.t;
  c[i] = 1;
}

/* { dg-final { scan-tree-dump "t\\\[i.*\\\] = 1;" "forwprop1" { xfail *-*-* }
} } */
/* { dg-final { scan-tree-dump "t\\\[i.*\\\] = 1;" "forwprop2" } } */
/* { dg-final { cleanup-tree-dump "forwprop?" } } */

---------

I found this while fixing up forwprop for the pointer plus branch.


-- 
           Summary: Missed forw prop with indirect ref and addr.
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31981