From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-479406-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 120446 invoked by alias); 5 Mar 2015 00:42:57 -0000
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
Received: (qmail 114601 invoked by uid 48); 5 Mar 2015 00:42:52 -0000
From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/65270] [5 regression] ICF needs to match TYPE attributes on memory accesses
Date: Thu, 05 Mar 2015 00:42:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: ipa
X-Bugzilla-Version: 5.0
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: hubicka at gcc dot gnu.org
X-Bugzilla-Status: REOPENED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 5.0
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields:
Message-ID: <bug-65270-4-z30e33Pz6w@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-65270-4@http.gcc.gnu.org/bugzilla/>
References: <bug-65270-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2015-03/txt/msg00550.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65270

--- Comment #19 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
I tried to construct a testcase for __restrict__ case:
int var;
const int *varptr=&var;
const int *__restrict__ varptr2=&var;

 int *__restrict__ varptr3 = &var;
 int *__restrict__ varptr4 = &var;

int *
return_valptr(int i)
{
  return varptr[i];
}
int * __restrict__
return_valptr2(int i)
{
  return varptr2[i];
}
int
testrestrict ()
{
  int *ptr = return_valptr (0);
  *ptr = 0;
  *varptr3 = 1;
  return *ptr;
}
int
testrestrict2 ()
{
  int *ptr = return_valptr2 (0);
  *ptr = 0;
  *varptr3 = 1;
  return *ptr;
}
int
testrestrict4 ()
{
  *varptr4 = 0;
  *varptr3 = 1;
  return *varptr4;
}

Here I would like restrict2 to return uncondtional 0, because ptr is taken from
a restrict pointer in a global var.  For whatever reason this optimization is
not happening (it happens in testrestrict4). So perhaps we are safe to
completely ignore restircts on vars, because we never get the flag in through
folding.