[Bug c/48734] New: ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[Bug c/48734] New: ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[regehr at cs dot utah.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

           Summary: ICE in eliminate_redundant_comparison, at
                    tree-ssa-reassoc.c:1321
           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 tmp013]$ current-gcc -O3 small.c
small.c: In function 'func_69':
small.c:12:1: internal compiler error: in eliminate_redundant_comparison, at
tree-ssa-reassoc.c:1321
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
[regehr@gamow tmp013]$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/uusoc/exports/scratch/regehr/z/compiler-install/gcc-r172870-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-r172870-install
--program-prefix=r172870- --enable-languages=c,c++
Thread model: posix
gcc version 4.7.0 20110422 (experimental) (GCC) 
[regehr@gamow tmp013]$ cat small.c
int
safe_21 (int si)
{
  return si == -2147483647 - 1 ? si : -si;
}

unsigned g_73;
unsigned g_79;
long g_178;
int g_709;
int *
func_69 (p_71)
{
  long l_78 = 1;
  int i;
  for (i = 0; l_78 < 10; l_78 += 1)
    for (g_79 = 0; g_79 < 1; g_79 = 1)
      g_178 &= safe_21 (p_71) > g_73;
  return 0;
}

void
func_60 (unsigned p_61, int *p_62, int *p_64)
{
  func_69 (p_61);
}

int
main (void)
{
  int *l_858 = &g_709;
  int i;
  for (i = 0; i < 1; g_73 = 1)
    for (; i < 1; i++)
      {
      }
  long l_857 = 1;
  func_60 (l_857, l_858, &g_709);
  func_60 (0, 0, 0);
  return 0;
}

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.04.26 06:14:36
          Component|c                           |tree-optimization
                 CC|                            |jakub at gcc dot gnu.org
     Ever Confirmed|0                           |1
            Summary|ICE in                      |[4.6/4.7 Regression] ICE in
                   |eliminate_redundant_compari |eliminate_redundant_compari
                   |son, at                     |son, at
                   |tree-ssa-reassoc.c:1321     |tree-ssa-reassoc.c:1321
   Target Milestone|---                         |4.6.1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-26 06:14:36 UTC ---
Related to PR45059, caused by
http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159189

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-26 06:56:46 UTC ---
Reduced testcase:

unsigned int
foo (int x, unsigned int y, unsigned int z)
{
  z &= (x == -__INT_MAX__ - 1 ? x : -x) > y;
  z &= (x == -__INT_MAX__ - 1 ? x : -x) > y;
  z &= (x == -__INT_MAX__ - 1 ? x : -x) > y;
  return z;
}

The problem is that fold (from maybe_fold_and_comparisons) in this case
canonicalizes the comparison in:
                /* The following case also applies to X < signed_max+1
                   and X >= signed_max+1 because previous transformations.  */
                if (code == LE_EXPR || code == GT_EXPR)
                  {
                    tree st;
                    st = signed_type_for (TREE_TYPE (arg1));   
                    return fold_build2_loc (loc,
                                        code == LE_EXPR ? GE_EXPR : LT_EXPR,
                                        type, fold_convert_loc (loc, st, arg0),
                                        build_int_cst (st, 0));
                  }
to include the extra cast to the signed cast and eliminate_redundant_comparison
is prepared to handle just one operation instead of two.  I think expecting
fold to return some particular form of result is just wrong assumption, it will
break sooner or later, so while the code could perhaps handle on extra cast or
something similar, it needs to give up on elimination if the returned
expression can't be handled.

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

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

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

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-26 07:37:58 UTC ---
Created attachment 24099
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24099
gcc46-pr48734.patch

Untested fix.

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-26 12:15:13 UTC ---
Looks good to me.

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-26 13:33:55 UTC ---
Author: jakub
Date: Tue Apr 26 13:33:49 2011
New Revision: 172967

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=172967
Log:
    PR tree-optimization/48734
    * tree-ssa-reassoc.c (eliminate_redundant_comparison): Give up
    if return value from maybe_fold_*_comparsions isn't something
    the code is prepared to handle.

    * gcc.c-torture/compile/pr48734.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr48734.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-reassoc.c

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-04-26 13:44:54 UTC ---
Author: jakub
Date: Tue Apr 26 13:44:51 2011
New Revision: 172969

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=172969
Log:
    PR tree-optimization/48734
    * tree-ssa-reassoc.c (eliminate_redundant_comparison): Give up
    if return value from maybe_fold_*_comparsions isn't something
    the code is prepared to handle.

    * gcc.c-torture/compile/pr48734.c: New test.

Added:
    branches/gcc-4_6-branch/gcc/testsuite/gcc.c-torture/compile/pr48734.c
Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_6-branch/gcc/tree-ssa-reassoc.c

[Bug tree-optimization/48734] [4.6/4.7 Regression] ICE in eliminate_redundant_comparison, at tree-ssa-reassoc.c:1321

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48734

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> 2011-04-26 13:48:10 UTC ---
Fixed.