[Bug c/52092] New: ICE: internal consistency failure

[Bug c/52092] New: ICE: internal consistency failure

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

             Bug #: 52092
           Summary: ICE: internal consistency failure
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: regehr@cs.utah.edu
                CC: chenyang@cs.utah.edu
              Host: x86_64-unknown-linux-gnu
            Target: x86_64-unknown-linux-gnu
             Build: x86_64-unknown-linux-gnu


[regehr@gamow tmp]$ current-gcc -v

Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/uusoc/exports/scratch/regehr/z/compiler-install/gcc-r183824-install/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r183824-install
--program-prefix=r183824- --enable-languages=c,c++
Thread model: posix
gcc version 4.7.0 20120202 (experimental) (GCC) 

[regehr@gamow tmp]$ current-gcc -c -Ofast small.c

small.c: In function 'fn16':
small.c:37:1: error: invalid rtl sharing found in the insn
(insn 125 124 126 25 (parallel [
            (set (reg:QI 75)
                (plus:QI (reg:QI 74)
                    (subreg:QI (reg:SI 67 [ D.1765 ]) 0)))
            (clobber (reg:CC 17 flags))
        ]) -1
     (nil))
small.c:37:1: error: shared rtx
(subreg:QI (reg:SI 67 [ D.1765 ]) 0)
small.c:37:1: internal compiler error: internal consistency failure
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

[regehr@gamow tmp]$ cat small.c

int a,b,c,d,e,f,g;

int fn4 ()
{
  c = d || a;
  return c ? a : b;
}

char fn6 (int p1, int p2)
{
  return p1 * p2;
}

int fn9 ()
{
  return e;
}

void fn16 ()
{
  for (;;)
    {
      int *h = 0;
      int i = 3;
      int **j = &h;
      if (fn9 ())
    {
      g = fn4 ();
      if (fn6 (i, g))
        {
          h = &f;
          *h = 0;
        }
      **j = 0;
    }
    }
}

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
          Component|c                           |rtl-optimization
   Target Milestone|---                         |4.7.0
            Summary|ICE: internal consistency   |[4.7 Regression] ICE:
                   |failure                     |internal consistency
                   |                            |failure

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-02 05:56:30 UTC ---
Here is a slightly more reduced testcase (which only has one function):
int a,b,c,d,e,f,g;

void fn16 ()
{
  for (;;)
    {
      int *h = 0;
      int **j = &h;
      if (e)
    {
      g = d||a?a:b;
      if ((char)(3*g))
        {
          h = &f;
          *h = 0;
        }
      **j = 0;
    }
    }
}

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-02-02
               Host|x86_64-unknown-linux-gnu    |
     Ever Confirmed|0                           |1
              Build|x86_64-unknown-linux-gnu    |

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-02 05:55:29 UTC ---
Confirmed, rtl loop unswitching is causing the ICE.  What is funny is we missed
this unswitch at the tree level but that might be because we only unswitch the
loop once rather than twice.

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-02 08:31:42 UTC ---
Looking at this too.

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-02 09:20:03 UTC ---
Started with http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183296

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-02 13:14:37 UTC ---
Created attachment 26552
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26552
gcc47-pr52092.patch

Untested fix.

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-03 11:55:33 UTC ---
Author: jakub
Date: Fri Feb  3 11:55:29 2012
New Revision: 183869

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183869
Log:
    PR rtl-optimization/52092
    * loop-unswitch.c (unswitch_single_loop): Call copy_rtx_if_shared
    on get_iv_value result.

    * gcc.c-torture/compile/pr52092.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr52092.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/loop-unswitch.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/52092] [4.7 Regression] ICE: internal consistency failure

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52092

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-02-03 12:03:49 UTC ---
Fixed.