From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-481051-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 122983 invoked by alias); 21 Mar 2015 05:59:10 -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 122960 invoked by uid 48); 21 Mar 2015 05:59:07 -0000
From: "hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/65502] New: pure-const should play well with clobbers.
Date: Sat, 21 Mar 2015 10:47:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
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: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter
Message-ID: <bug-65502-4@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/msg02195.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65502

            Bug ID: 65502
           Summary: pure-const should play well with clobbers.
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org

I just noticed that C++ destructors are not conisdered const/pure:

 local analysis of Smarts::IterateScheduler<Smarts::Stub>::~IterateScheduler()
   scanning: MEM[(struct  &)this_2(D)] ={v} {CLOBBER};
    Indirect ref write is not const/pure
  scanning: return;
Smarts::IterateScheduler<Smarts::Stub>::~IterateScheduler() (struct
IterateScheduler * const this)
{
  <bb 2>:
  MEM[(struct  &)this_2(D)] ={v} {CLOBBER};
  return;

}

This is of course wrong, empty function is const.  One issue however is that we
want to preserve CLOBBER when inlining, so during early passes we may want to
keep clobbers nonpure.