[Bug tree-optimization/44913] New: [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[Bug tree-optimization/44913] New: [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[zsojka at seznam dot cz]

Command line:
$ gcc -O[123] -ftree-vectorize gcc.dg/pr44838.c && ./a.out

Output:
$ /mnt/svn/gcc-trunk/binary-162056-lto-fortran-checking-yes-rtl-df/bin/gcc -O1
-ftree-vectorize pr44838.i
$ ./a.out 
Aborted

Tested revisions:
r162056 - fail
r161659 - fail
r161170 - OK


-- 
           Summary: [4.6 Regression] -ftree-vectorize causes FAIL:
                    gcc.dg/pr44838.c execution test
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zsojka at seznam dot cz
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
   Target Milestone|---                         |4.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[hjl dot tools at gmail dot com]

------- Comment #1 from hjl dot tools at gmail dot com  2010-07-11 23:11 -------
This is caused by revision 161655:

http://gcc.gnu.org/ml/gcc-cvs/2010-07/msg00006.html


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2010-07-23 12:35 -------
Confirmed.  We end up vectorizing

void
foo (int *a, int n)
{
  int *lasta = a + n;
  for (; a != lasta; a++)
    {
      *a *= 2;
      a[1] = a[-1] + a[-2];
    }
}

not seeing the dependence of *a vs a[-1] because via
initialize_data_dependence_relation we ask the alias-oracle whether
*a may alias a[-1] (which it doesn't).  So we end up not computing
a dependence distance.

May we not use the alias-oracle (on the full ref) here?


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |spop at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-07-23 12:35:43
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[jakub at gcc dot gnu dot org]

-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

Richard Guenther <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 #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-10-14 10:38:45 UTC ---
Mine.

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

--- Comment #4 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-10-14 15:51:22 UTC ---
Author: rguenth
Date: Thu Oct 14 15:51:15 2010
New Revision: 165473

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=165473
Log:
2010-10-14  Richard Guenther  <rguenther@suse.de>

    PR tree-optimization/44913
    * tree-data-ref.c (disjoint_objects_p): Remove.
    (dr_may_alias_p): Simplify.  Only hand the base object to
    the alias-oracle.
    * tree-ssa-alias.c (ptr_deref_may_alias_decl_p): Handle
    some more trees, bail out instead of asserting.
    (ptr_derefs_may_alias_p): Likewise.  Export.
    (refs_may_alias_p_1): Handle STRING_CSTs.
    * tree-ssa-alias.h (ptr_derefs_may_alias_p): Declare.

    * gcc.dg/torture/pr44913.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr44913.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-data-ref.c
    trunk/gcc/tree-ssa-alias.c
    trunk/gcc/tree-ssa-alias.h

[Bug tree-optimization/44913] [4.6 Regression] -ftree-vectorize causes FAIL: gcc.dg/pr44838.c execution test

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44913

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

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

--- Comment #5 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-10-14 15:55:34 UTC ---
Fixed.