🚀 go-pugleaf

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2010.12.16 00:45:57
                 CC|                            |spop at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> 2010-12-16 00:45:57 UTC ---
Revision 131435:

http://gcc.gnu.org/ml/gcc-cvs/2008-01/msg00195.html

fixed ICE and generated wrong code.

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> 2010-12-16 00:49:40 UTC ---
It is related to PR 34017.

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at redhat dot com

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> 2010-12-16 00:51:24 UTC ---
Patch was posted at

http://gcc.gnu.org/ml/gcc-patches/2008-01/msg00371.html

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.3.6

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-12-17 16:17:39 UTC ---
I think the bug is in that gcc_loop_to_lambda_loop doesn't record whether the
SSA_NAME compared in the exit condition was the induction var or incremented
induction var.
E.g. on ltrans-3.c testcase we have
<bb 5>:
  # j_25 = PHI <j_15(4), 0(9)>
...
  j_15 = j_25 + 1;
  if (N.2_3 > j_15)
    goto <bb 4>;
  else
    goto <bb 6>;
and thus the exit condition tests the incremented iv (gcc_loop_to_lambda_loop
btw. doesn't bother to check whether the def stmt of the rhs of exit condition
here actually increments by step, and doesn't bother to check that step fits
into int (so I guess step like 0x100000001ULL would cause trouble).
It just records lower bound 0, upper bound N.2_3 - 1 here and step 1.
But with -Os -ftree-loop-linear on this testcase we have before ltrans:
  j_12 = j_2 + 1;

<bb 4>:
  # j_2 = PHI <0(7), j_12(3)>
  if (j_2 < n_5(D))
    goto <bb 3>;
  else
    goto <bb 5>;
Here similarly it records lower bound 0, upper bound n_5 - 1 and step 1.
But there is an important difference in between the two.
In the former case we correctly use
  gimple_cond_set_condition (exitcond, testtype, newupperbound, ivvarinced);
but we use it in the second case too, which is wrong.

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-12-17 17:14:01 UTC ---
Created attachment 22801
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id"801
gcc46-pr46970.patch

Untested patch that fixes this and keeps ltrans-3.c working.

I don't feel very good about the +-1 * stepint extra adjustments the code did
and still does though, I'm afraid there could be problems with that if there is
an overflow, but it would be much more work to adjust lambda-code.c so that it
deals with this properly.

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

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

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

--- Comment #6 from Sebastian Pop <spop at gcc dot gnu.org> 2011-01-18 20:54:55 UTC ---
Author: spop
Date: Tue Jan 18 20:54:52 2011
New Revision: 168967

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev8967
Log:
Add testcase for PR46970.

2011-01-18  Sebastian Pop  <sebastian.pop@amd.com>

    PR tree-optimization/46970
    * gcc.dg/graphite/pr46970.c: New.

Added:
    branches/graphite/gcc/testsuite/gcc.dg/graphite/pr46970.c
Modified:
    branches/graphite/gcc/ChangeLog.graphite

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

Sebastian Pop <spop at gcc dot gnu.org> changed:

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

--- Comment #7 from Sebastian Pop <spop at gcc dot gnu.org> 2011-01-18 20:56:30 UTC ---
Fixed on the graphite branch.

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

--- Comment #8 from Sebastian Pop <spop at gcc dot gnu.org> 2011-01-25 21:25:35 UTC ---
Author: spop
Date: Tue Jan 25 21:25:24 2011
New Revision: 169257

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev9257
Log:
Add testcase for PR46970.

2011-01-18  Sebastian Pop  <sebastian.pop@amd.com>

    PR tree-optimization/46970
    * gcc.dg/graphite/pr46970.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/graphite/pr46970.c
Modified:
    trunk/gcc/testsuite/ChangeLog

http://gcc.gnu.org/bugzilla/show_bug.cgi?idF970

Sebastian Pop <spop at gcc dot gnu.org> changed:

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

--- Comment #9 from Sebastian Pop <spop at gcc dot gnu.org> 2011-01-25 21:28:37 UTC ---
Fixed.