Revert accidental checkin.

[pf3gnuchains/gcc-fork.git] / gcc / graphite-flattening.c

diff --git a/gcc/graphite-flattening.c b/gcc/graphite-flattening.c
index ccd0f5f..33f25e0 100644 (file)
--- a/gcc/graphite-flattening.c
+++ b/gcc/graphite-flattening.c
@@ -277,12 +277,26 @@ lst_project_loop (lst_p outer, lst_p inner, mpz_t stride)
       ppl_delete_Linear_Expression (expr);
 
       /* Remove inner loop and the static schedule of its body.  */
-      ds = XNEWVEC (ppl_dimension_type, 2);
-      ds[0] = inner_dim;
-      ds[1] = inner_dim + 1;
-      ppl_Polyhedron_remove_space_dimensions (poly, ds, 2);
-      PBB_NB_SCATTERING_TRANSFORM (pbb) -= 2;
-      free (ds);
+      /* FIXME: As long as we use PPL we are not able to remove the old
+        scattering dimensions.  The reason is that these dimensions are not
+        entirely unused.  They are not necessary as part of the scheduling
+        vector, as the earlier dimensions already unambiguously define the
+        execution time, however they may still be needed to carry modulo
+        constraints as introduced e.g. by strip mining.  The correct solution
+        would be to project these dimensions out of the scattering polyhedra.
+        In case they are still required to carry modulo constraints they should be kept
+        internally as existentially quantified dimensions.  PPL does only support
+         projection of rational polyhedra, however in this case we need an integer
+        projection. With isl this will be trivial to implement.  For now we just
+        leave the dimensions. This is a little ugly, but should be correct.  */
+      if (0) {
+       ds = XNEWVEC (ppl_dimension_type, 2);
+       ds[0] = inner_dim;
+       ds[1] = inner_dim + 1;
+       ppl_Polyhedron_remove_space_dimensions (poly, ds, 2);
+       PBB_NB_SCATTERING_TRANSFORM (pbb) -= 2;
+       free (ds);
+      }
     }
 
   mpz_clear (x);
@@ -412,7 +426,21 @@ lst_do_flatten (lst_p lst)
     if (LST_LOOP_P (l))
       {
        res |= lst_flatten_loop (l, zero);
-       remove_unused_scattering_dimensions (l);
+
+       /* FIXME: As long as we use PPL we are not able to remove the old
+          scattering dimensions.  The reason is that these dimensions are not
+          entirely unused.  They are not necessary as part of the scheduling
+          vector, as the earlier dimensions already unambiguously define the
+          execution time, however they may still be needed to carry modulo
+          constraints as introduced e.g. by strip mining.  The correct solution
+          would be to project these dimensions out of the scattering polyhedra.
+          In case they are still required to carry modulo constraints they should be kept
+          internally as existentially quantified dimensions.  PPL does only support
+           projection of rational polyhedra, however in this case we need an integer
+          projection. With isl this will be trivial to implement.  For now we just
+          leave the dimensions. This is a little ugly, but should be correct.  */
+       if (0)
+         remove_unused_scattering_dimensions (l);
       }
 
   lst_update_scattering (lst);