[Bug tree-optimization/56349] New: ICE in create_preheader at cfgloopmanip.c:1525

[Bug tree-optimization/56349] New: ICE in create_preheader at cfgloopmanip.c:1525

[antoine.balestrat at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

             Bug #: 56349
           Summary: ICE in create_preheader at cfgloopmanip.c:1525
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: antoine.balestrat@gmail.com


Hello !
Using GCC 4.8.0 as of 20130215 :

$ cat preh.c
int a, b;
short c;

void f(void)
{
    int *k = a = 0;

    for(; a < 2; a++);

    if(!!(b |= a < 3) - 1)
    {
        if(0)
            for (;; a++)
            {
                for (; c; *k = 0);
lbl1:
                ;
            }

        for(; *k; k++)
        {
            c = b ? : a;

            if (c)
lbl2:
                b = 0;
        }
        goto lbl1;
    }

    for(;; b++)
    {
        if(b)
            goto lbl2;

        k = &b;
    }
}

$ xgcc -O2 -ftree-partial-pre -w preh.c
preh.c: In function ‘f’:
preh.c:38:1: internal compiler error: Segmentation fault
 }
 ^
0x8dba2f crash_signal
    ../../srcdir/gcc/toplev.c:332
0x5ffcdb create_preheader(loop*, int)
    ../../srcdir/gcc/cfgloopmanip.c:1525
0x600069 create_preheaders(int)
    ../../srcdir/gcc/cfgloopmanip.c:1577
0x7de31e apply_loop_flags
    ../../srcdir/gcc/loop-init.c:61
0x7de3df loop_optimizer_init(unsigned int)
    ../../srcdir/gcc/loop-init.c:108
0x7de4ba rtl_loop_init
    ../../srcdir/gcc/loop-init.c:329
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

[Bug tree-optimization/56349] ICE in create_preheader at cfgloopmanip.c:1525

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-02-15
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.8.0
     Ever Confirmed|0                           |1
      Known to fail|                            |4.8.0

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> 2013-02-15 19:44:57 UTC ---
Confirmed.  Started with
http://gcc.gnu.org/viewcvs?view=revision&revision=195879.

[Bug tree-optimization/56349] ICE in create_preheader at cfgloopmanip.c:1525

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |rguenth at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-18 09:17:33 UTC ---
Mine.

[Bug tree-optimization/56349] ICE in create_preheader at cfgloopmanip.c:1525

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-18 09:40:39 UTC ---
The issue here is that we have an inner loop that has an exit edge that is
at the same time the latch edge for its outer loop (that is, its latch
does not belong to it - but we do not have LOOPS_HAVE_SIMPLE_LATCHES - yet).
In this case it seems that loop->latch may be not set, even if
we disambiguated loops with multiple latches.  We do not verify that
with disambiguated multiple latch loops we have ->latch set, which reveals
one bug in flow_loops_find.  Which transforms this bug into sth totally
different ;)

[Bug middle-end/56349] [4.8 Regression] ICE in create_preheader at cfgloopmanip.c:1525

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |middle-end
            Summary|ICE in create_preheader at  |[4.8 Regression] ICE in
                   |cfgloopmanip.c:1525         |create_preheader at
                   |                            |cfgloopmanip.c:1525

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-18 13:03:52 UTC ---
Fixed.

[Bug middle-end/56349] [4.8 Regression] ICE in create_preheader at cfgloopmanip.c:1525

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-18 13:05:49 UTC ---
Eh, fixed!

[Bug middle-end/56349] [4.8 Regression] ICE in create_preheader at cfgloopmanip.c:1525

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56349

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> 2013-02-18 13:09:24 UTC ---
Author: rguenth
Date: Mon Feb 18 13:09:17 2013
New Revision: 196119

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196119
Log:
2013-02-18  Richard Biener  <rguenther@suse.de>

        PR middle-end/56349
        * gcc.dg/torture/pr56350.c: Move ...
        * gcc.dg/torture/pr56349.c: ... here.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr56349.c
      - copied unchanged from r196118,
trunk/gcc/testsuite/gcc.dg/torture/pr56350.c
Removed:
    trunk/gcc/testsuite/gcc.dg/torture/pr56350.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog