From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-385610-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 3292 invoked by alias); 8 Mar 2012 05:18:20 -0000
Received: (qmail 3282 invoked by uid 22791); 8 Mar 2012 05:18:18 -0000
X-SWARE-Spam-Status: No, hits=-2.8 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00,TW_CR,TW_RX
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 08 Mar 2012 05:18:05 +0000
From: "cltang at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/52528] New: combine bug (powerpc testcase)
Date: Thu, 08 Mar 2012 05:18:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: cltang 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-Changed-Fields:
Message-ID: <bug-52528-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
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: 2012-03/txt/msg00663.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52528

             Bug #: 52528
           Summary: combine bug (powerpc testcase)
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: cltang@gcc.gnu.org
            Target: powerc-linux


The below testcase:
struct S {
  unsigned a : 30;
  unsigned b :  2;
};

int foo (int b)
{
  struct S s = {0};
  s.b = b;
  return bar (0x000b0010, 0x00040100ULL, *(unsigned long *)&s);
}

currently on trunk (target powerpc) compiles to:
foo:
        lis 6,0x4
        li 5,0
        ori 6,6,256
        li 7,0
        crxor 6,6,6
        b bar

Notice the incorrect code generated: no construction of the 1st arg (reg 3),
and
wrong code for the 3rd arg (reg 7)

I have diagnosed this as a problem in combine, and have a patch in testing.
Opening this issue for status tracking.