From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-161371-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 27371 invoked by alias); 9 Oct 2005 09:56:12 -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 27364 invoked by uid 48); 9 Oct 2005 09:56:11 -0000
Date: Sun, 09 Oct 2005 09:56:00 -0000
Message-ID: <20051009095611.27363.qmail@sourceware.org>
X-Bugzilla-Reason: CC
References: <bug-19637-10053@http.gcc.gnu.org/bugzilla/>
Subject: [Bug tree-optimization/19637] Missed VRP and FRE opportunities in the presence of casts
In-Reply-To: <bug-19637-10053@http.gcc.gnu.org/bugzilla/>
Reply-To: gcc-bugzilla@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org
From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
X-SW-Source: 2005-10/txt/msg01069.txt.bz2
List-Id: <gcc-bugs.sourceware.org>



------- Comment #8 from rguenth at gcc dot gnu dot org  2005-10-09 09:56 -------
Another one is the following (without any possible aliasing problems):

int foo_charchar(void)
{
        char i[2*sizeof(int)];
        new (i) Foo();
        return reinterpret_cast<Foo*>(&i[0])->i[0];
}

where we miss the FRE opportunity for the cast:

<bb 0>:
  iftmp.0 = (struct Foo *) &i[0];
  iftmp.0->i[0] = 1;
  D.2097 = (struct Foo *) &i[0];
  return D.2097->i[0];


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Missed constant propagation |Missed VRP and FRE
                   |with placement new          |opportunities in the
                   |                            |presence of casts


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19637