From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-return-143031-listarch-gcc=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 28095 invoked by alias); 16 Dec 2007 17:53:37 -0000
Received: (qmail 28086 invoked by uid 22791); 16 Dec 2007 17:53:37 -0000
X-Spam-Check-By: sourceware.org
Received: from province.act-europe.fr (HELO province.act-europe.fr) (212.99.106.214)     by sourceware.org (qpsmtpd/0.31) with ESMTP; Sun, 16 Dec 2007 17:53:30 +0000
Received: from localhost (localhost [127.0.0.1]) 	by filtered-province.act-europe.fr (Postfix) with ESMTP id A29041648EA 	for <gcc@gcc.gnu.org>; Sun, 16 Dec 2007 18:53:17 +0100 (CET)
Received: from province.act-europe.fr ([127.0.0.1]) 	by localhost (province.act-europe.fr [127.0.0.1]) (amavisd-new, port 10024) 	with ESMTP id dyPPx4lBZoEj for <gcc@gcc.gnu.org>; 	Sun, 16 Dec 2007 18:53:17 +0100 (CET)
Received: from [192.168.1.3] (dyn-83-156-59-86.ppp.tiscali.fr [83.156.59.86]) 	(using TLSv1 with cipher RC4-MD5 (128/128 bits)) 	(No client certificate requested) 	by province.act-europe.fr (Postfix) with ESMTP id 5B6B41648E9 	for <gcc@gcc.gnu.org>; Sun, 16 Dec 2007 18:53:17 +0100 (CET)
From: Eric Botcazou <ebotcazou@adacore.com>
To: gcc@gcc.gnu.org
Subject: Problem with SSA inlining and default defs
Date: Sun, 16 Dec 2007 18:01:00 -0000
User-Agent: KMail/1.7.1
MIME-Version: 1.0
Content-Type: Multipart/Mixed;   boundary="Boundary-00=_VZWZHv3j8kVF3v0"
Message-Id: <200712161854.29543.ebotcazou@adacore.com>
Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc/>
List-Post: <mailto:gcc@gcc.gnu.org>
List-Help: <http://gcc.gnu.org/ml/>
Sender: gcc-owner@gcc.gnu.org
X-SW-Source: 2007-12/txt/msg00471.txt.bz2


--Boundary-00=_VZWZHv3j8kVF3v0
Content-Type: text/plain;
  charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Content-length: 679

Hi,

How SSA inlining and default defs for uninitialized variables are supposed to 
interact?  Suppose you have the following situation

    BB0 ...
     |   \
(ab) |    BB1 s_2 = f(s_1(D))
     |   /
    BB2 s_3 = PHI <s_1(D), s2>

in a function that gets inlined into a loop.  The liveness of s_1(D) in BB0 
will propagate to BB2 along the backwards edge and you get overlapping live 
ranges for s_1(D) and s_3.  If s_1(D) is SSA_NAME_OCCURS_IN_ABNORMAL_PHI, the 
compilation will abort during SSA coalescing because they must be coalesced.

This is on the mainline, Ada testcase attached, run 'gnatchop' on it and 
compile at -O -gnatp.

Thanks in advance.

-- 
Eric Botcazou

--Boundary-00=_VZWZHv3j8kVF3v0
Content-Type: text/plain;
  charset="us-ascii";
  name="p.ada"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
	filename="p.ada"
Content-length: 508

package Q is

    procedure Read(S : out Integer);
    procedure Restore(S : in out Integer);

end Q;
package P is

    type Int_Ptr is access all Integer;
    procedure Exec(P : Int_Ptr);

end P;
with Q; use Q;

package body P is

    procedure Lock is
        S : Integer;
    begin
        Read(S);
        Restore(S);
    exception
        when others => Restore(S);
    end;

    procedure Exec(P : Int_Ptr) is
    begin
        while P /= NULL loop
            Lock;
        end loop;
    end;

end P;

--Boundary-00=_VZWZHv3j8kVF3v0--