From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-399927-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 28286 invoked by alias); 2 Sep 2012 15:15:15 -0000
Received: (qmail 28271 invoked by uid 22791); 2 Sep 2012 15:15:13 -0000
X-SWARE-Spam-Status: No, hits=-4.3 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED
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; Sun, 02 Sep 2012 15:15:00 +0000
From: "steven at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/54455] [4.7/4.8 Regression] ICE: RTL check: expected elt 3 type 'B', have '0' (rtx barrier) in compute_bb_for_insn, at cfgrtl.c:418
Date: Sun, 02 Sep 2012 15:15:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: steven at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 4.7.2
X-Bugzilla-Changed-Fields: CC
Message-ID: <bug-54455-4-XtKBAn4NRq@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-54455-4@http.gcc.gnu.org/bugzilla/>
References: <bug-54455-4@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: 2012-09/txt/msg00093.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54455

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|steven at gcc dot gnu.org   |abel at gcc dot gnu.org

--- Comment #8 from Steven Bosscher <steven at gcc dot gnu.org> 2012-09-02 15:14:58 UTC ---
(In reply to comment #7)
But actually the problem is only visible if you print non-slim rtl. Before
sched1:

(jump_insn 13 12 15 3 (parallel [
            (asm_operands/v ("") ("") 0 [
                    (reg:SI 62)
                    (reg:SI 63)
                ]   
                 [
                    (asm_input:SI ("r") (null):0)
                    (asm_input:SI ("r") (null):0)
                ] 
                 [
                    (label_ref:DI 17)
                ] t.c:11)
            (clobber (reg:QI 18 fpsr))
            (clobber (reg:QI 17 flags))
            (clobber (mem:BLK (scratch) [0 A8]))
        ]) t.c:3 -1
     (nil)      
 -> 17)
(note 15 13 17 ("lab") NOTE_INSN_DELETED_LABEL 3)
(code_label 17 15 18 4 1 "" [1 uses])
(note 18 17 0 4 [bb 4] NOTE_INSN_BASIC_BLOCK)

After sched1:

(jump_insn 13 12 15 3 (parallel [
            (asm_operands/v ("") ("") 0 [
                    (reg:SI 62)
                    (reg:SI 63) 
                ]
                 [   
                    (asm_input:SI ("r") (null):0)
                    (asm_input:SI ("r") (null):0)
                ]
                 [   
                    (label_ref:DI 17)     <--- ref to code_label 17
                ] t.c:11)
            (clobber (reg:QI 18 fpsr))
            (clobber (reg:QI 17 flags))
            (clobber (mem:BLK (scratch) [0 A8]))
        ]) t.c:3 -1
     (expr_list:REG_DEAD (reg:SI 63)
        (expr_list:REG_DEAD (reg:SI 62) 
            (expr_list:REG_UNUSED (reg:QI 18 fpsr)
                (expr_list:REG_UNUSED (reg:QI 17 flags)
                    (nil)))))
 -> 17)
(note 15 13 21 ("lab") NOTE_INSN_DELETED_LABEL 3)
...but code_label 17 has disappeared...
(note 21 15 0 NOTE_INSN_DELETED)

Note that the jump_insn now jumps to a non-existing label.

There are two problems here:

1. verify_flow_info should detect that a jump references a non-existing label,
and abort if that happens

2. The code_label 17 shouldn't be removed by the selective scheduler because
it's still referenced.