[Bug c/47899] New: ICE in get_loop_body, at cfgloop.c:831

[Bug c/47899] New: ICE in get_loop_body, at cfgloop.c:831

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

           Summary: ICE in get_loop_body, at cfgloop.c:831
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: regehr@cs.utah.edu
                CC: chenyang@cs.utah.edu
              Host: i686-pc-linux-gnu
            Target: i686-pc-linux-gnu
             Build: i686-pc-linux-gnu


regehr@home:~/volatile/bugs/tmp351$ current-gcc -v
Using built-in specs.

COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/mnt/z/z/compiler-install/gcc-r170512-install/libexec/gcc/i686-pc-linux-gnu/4.6.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/mnt/z/z/compiler-install/gcc-r170512-install
--program-prefix=r170512- --enable-languages=c,c++
Thread model: posix
gcc version 4.6.0 20110226 (experimental) (GCC) 

regehr@home:~/volatile/bugs/tmp351$ current-gcc -O -funroll-loops small.c -o
small

small.c: In function ‘main’:
small.c:53:1: internal compiler error: in get_loop_body, at cfgloop.c:831
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

regehr@home:~/volatile/bugs/tmp351$ cat small.c


static unsigned
foo (unsigned ui1, unsigned ui2)
{
  return ui1 - ui2;
}

static unsigned g_5[3][1][9] = {
};

static short g_17;

static short *g_80[4] = {
  &g_17, &g_17, &g_17, &g_17
};

static short **g_79[5] = {
  &g_80[1], &g_80[1], &g_80[1], &g_80[1], &g_80[1]
};

static int g_132;
static short ***volatile g = &g_79[1];
static unsigned g_566;

static void func_1 (void)
{
lbl_777:*g;
  for (; g; g += 0)
    for (; g; g += 1)
      {
    for (;;)
      {
      }
      }
lbl_802:if (g_566)
    goto lbl_777;
  for (g_132 = 0; g_132 >= 0; g_132 = foo (g_132, 1))
    {
      if (g_5[+3][+1][+9] || **g)
    {
      for (; g; g += 1)
        {
        }
    }
      else
    goto lbl_802;
    }
}

int main (int argc, char *argv[])
{
  func_1 ();
}

[Bug rtl-optimization/47899] ICE in get_loop_body, at cfgloop.c:831

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|i686-pc-linux-gnu           |i686-pc-linux-gnu,
                   |                            |x86_64-*-*
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|                            |2011.02.27 15:04:45
          Component|c                           |rtl-optimization
     Ever Confirmed|0                           |1
      Known to fail|                            |4.5.2, 4.6.0

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-02-27 15:04:45 UTC ---
Confirmed.  The ICE happens during RTL complete loop peeling.

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
      Known to work|                            |4.4.5
   Target Milestone|---                         |4.5.3
            Summary|ICE in get_loop_body, at    |[4.5/4.6 Regression] ICE in
                   |cfgloop.c:831               |get_loop_body, at
                   |                            |cfgloop.c:831

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-27 19:44:44 UTC ---
ICE starts with http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=145357

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-02-28 09:39:52 UTC ---
Somewhat simplified testcase (still for -O -funroll-loops):

extern unsigned int a, b, c;
extern int d;

static int
foo (void)
{
lab:
  if (b)
    for (d = 0; d >= 0; d--)
      if (a || c)
    for (; c; c++)
      ;
      else
    goto lab;
}

int
main ()
{
  foo ();
  return 0;
}

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[rakdver at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #4 from Zdenek Dvorak <rakdver at gcc dot gnu.org> 2011-03-01 22:13:15 UTC ---
Created attachment 23508
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23508
proposed fix

When the non-exit path is removed during the complete peeling of the loop, we
may need to move some basic blocks up the loop hierarchy (this happens when
this removal destroys the path from the bb to the latch of the considered
superloop).  We achieve this by iteratively moving blocks to the common
superloop of their successors; when a block is moved up the hierarchy, we add
its predecessors to the queue to process.  However, when the predecessor of bb
already belongs to a loop higher in the hierarchy, we do not put it to the
queue (since the change at bb obviously cannot affect the placement of the
predecessor).  This gets slightly more complicated by the need to handle
subloops; in the described heuristics, we were mistakenly comparing the
position of the predecessor with the subloop, instead of with the loop to that
the subloop was moved.

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-02 17:48:27 UTC ---
Thanks, this patch seems to work (I've bootstrapped/regtested it on
x86_64-linux and i686-linux together with the #c3 testcase with
/* PR rtl-optimization/47899 */
/* { dg-do compile } */
/* { dg-options "-O -funroll-loops" } */
under gcc/testsuite/gcc.dg/pr47899.c, no regressions).

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[rakdver at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #6 from Zdenek Dvorak <rakdver at gcc dot gnu.org> 2011-03-04 22:41:48 UTC ---
(In reply to comment #5)
> Thanks, this patch seems to work (I've bootstrapped/regtested it on
> x86_64-linux and i686-linux together with the #c3 testcase with
> /* PR rtl-optimization/47899 */
> /* { dg-do compile } */
> /* { dg-options "-O -funroll-loops" } */
> under gcc/testsuite/gcc.dg/pr47899.c, no regressions).

Jakub, are you going to commit the patch (you can consider it approved)?  I can
do it, of course, but since you already finished the testing...

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-04 22:44:40 UTC ---
(In reply to comment #6)
> (In reply to comment #5)
> > Thanks, this patch seems to work (I've bootstrapped/regtested it on
> > x86_64-linux and i686-linux together with the #c3 testcase with
> > /* PR rtl-optimization/47899 */
> > /* { dg-do compile } */
> > /* { dg-options "-O -funroll-loops" } */
> > under gcc/testsuite/gcc.dg/pr47899.c, no regressions).
> 
> Jakub, are you going to commit the patch (you can consider it approved)?  I can
> do it, of course, but since you already finished the testing...

I can do so, just not sure how exactly would you prefer to describe your
changes in ChangeLog.

[Bug rtl-optimization/47899] [4.5/4.6 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-05 14:28:19 UTC ---
Author: jakub
Date: Sat Mar  5 14:28:14 2011
New Revision: 170699

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=170699
Log:
    PR rtl-optimization/47899
    * cfgloopmanip.c (fix_bb_placements): Fix first argument
    to flow_loop_nested_p when moving the loop upward.

    * gcc.dg/pr47899.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr47899.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgloopmanip.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.6.0
            Summary|[4.5/4.6 Regression] ICE in |[4.5 Regression] ICE in
                   |get_loop_body, at           |get_loop_body, at
                   |cfgloop.c:831               |cfgloop.c:831
      Known to fail|4.6.0                       |

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-05 14:36:10 UTC ---
Fixed on the trunk so far.

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

Zdenek Sojka <zsojka at seznam dot cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zsojka at seznam dot cz

--- Comment #10 from Zdenek Sojka <zsojka at seznam dot cz> 2011-03-14 18:44:24 UTC ---
The testcase still ICEs the same way with custom flags:
(r170934, x86_64-linux)

$ gcc -O -funroll-loops -fthread-jumps -fno-tree-ch gcc.dg/pr47899.c
gcc.dg/pr47899.c: In function 'main':
gcc.dg/pr47899.c:26:1: internal compiler error: in get_loop_body, at
cfgloop.c:831
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #11 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-03-15 10:09:25 UTC ---
Confirmed, but can you track this in a new bug?

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #12 from Zdenek Sojka <zsojka at seznam dot cz> 2011-03-15 10:50:35 UTC ---
Thank you for reply. I opened PR48133 for the testcase from comment #10.

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #13 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-18 14:02:27 UTC ---
Author: rguenth
Date: Mon Apr 18 14:02:22 2011
New Revision: 172647

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=172647
Log:
2011-04-18  Richard Guenther  <rguenther@suse.de>

    Backported from 4.6 branch 
    2011-03-11  Jakub Jelinek  <jakub@redhat.com>

    PR c++/48035
    * init.c (build_zero_init_1): Extracted from build_zero_init.
    Add FIELD_SIZE argument, if non-NULL and field bit_position
    as not smaller than that, don't add that field's initializer.
    Pass DECL_SIZE as last argument to build_zero_init_1
    for DECL_FIELD_IS_BASE fields.
    (build_zero_init): Use build_zero_init_1.

    * g++.dg/inherit/virtual8.C: New test.

    2011-03-05  Zdenek Dvorak  <ook@ucw.cz>

    PR rtl-optimization/47899
    * cfgloopmanip.c (fix_bb_placements): Fix first argument
    to flow_loop_nested_p when moving the loop upward.

    * gcc.dg/pr47899.c: New test.

    2011-03-15  Richard Guenther  <rguenther@suse.de>

    PR middle-end/48031
    * fold-const.c (fold_indirect_ref_1): Do not create new variable-sized
    or variable-indexed array accesses when in gimple form.

Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/cfgloopmanip.c
    branches/gcc-4_5-branch/gcc/cp/ChangeLog
    branches/gcc-4_5-branch/gcc/cp/init.c
    branches/gcc-4_5-branch/gcc/fold-const.c
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

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

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

--- Comment #14 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-18 14:03:42 UTC ---
Fixed.

[Bug rtl-optimization/47899] [4.5 Regression] ICE in get_loop_body, at cfgloop.c:831

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47899

--- Comment #15 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-18 14:37:18 UTC ---
Author: rguenth
Date: Mon Apr 18 14:37:08 2011
New Revision: 172652

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=172652
Log:
2011-04-18  Richard Guenther  <rguenther@suse.de>

    Backported from 4.6 branch 
    2011-03-11  Jakub Jelinek  <jakub@redhat.com>

    PR c++/48035
    * init.c (build_zero_init_1): Extracted from build_zero_init.
    Add FIELD_SIZE argument, if non-NULL and field bit_position
    as not smaller than that, don't add that field's initializer.
    Pass DECL_SIZE as last argument to build_zero_init_1
    for DECL_FIELD_IS_BASE fields.
    (build_zero_init): Use build_zero_init_1.

    * g++.dg/inherit/virtual8.C: New test.

    2011-03-05  Zdenek Dvorak  <ook@ucw.cz>

    PR rtl-optimization/47899
    * cfgloopmanip.c (fix_bb_placements): Fix first argument
    to flow_loop_nested_p when moving the loop upward.

    * gcc.dg/pr47899.c: New test.

    2011-03-15  Richard Guenther  <rguenther@suse.de>

    PR middle-end/48031
    * fold-const.c (fold_indirect_ref_1): Do not create new variable-sized
    or variable-indexed array accesses when in gimple form.

Added:
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/inherit/virtual8.C
    branches/gcc-4_5-branch/gcc/testsuite/gcc.dg/pr47899.c