[Bug tree-optimization/41101] [4.4/4.5 Regression] ICE in compute_antic, at tree-ssa-pre.c:2419

[rguenth at gcc dot gnu dot org]

------- Comment #18 from rguenth at gcc dot gnu dot org  2009-09-06 17:41 -------
Do you mean sth like the following?  Simply assuming that the maximal-set is
all ones and obviously translating all ones also results in all ones.

Index: gcc/tree-ssa-pre.c
===================================================================
--- gcc/tree-ssa-pre.c  (revision 151459)
+++ gcc/tree-ssa-pre.c  (working copy)
@@ -2201,49 +2201,45 @@ compute_antic_aux (basic_block block, bo
     {
       VEC(basic_block, heap) * worklist;
       size_t i;
-      basic_block bprime, first;
+      basic_block bprime, first = NULL;

       worklist = VEC_alloc (basic_block, heap, EDGE_COUNT (block->succs));
       FOR_EACH_EDGE (e, ei, block->succs)
-       VEC_quick_push (basic_block, worklist, e->dest);
-      first = VEC_index (basic_block, worklist, 0);
-
-      if (phi_nodes (first))
        {
-         bitmap_set_t from = ANTIC_IN (first);
-
-         if (!BB_VISITED (first))
-           from = maximal_set;
-         phi_translate_set (ANTIC_OUT, from, block, first);
+         if (!first
+             && BB_VISITED (e->dest))
+           first = e->dest;
+         else if (BB_VISITED (e->dest))
+           VEC_quick_push (basic_block, worklist, e->dest);
+       }
+
+      /* Of multiple successors we have to have visited one already.  */
+      if (!first)
+       {
+         SET_BIT (changed_blocks, block->index);
+         BB_VISITED (block) = 0;
+         BB_DEFERRED (block) = 1;
+         changed = true;
+         VEC_free (basic_block, heap, worklist);
+         goto maybe_dump_sets;
        }
+
+      if (phi_nodes (first))
+       phi_translate_set (ANTIC_OUT, ANTIC_IN (first), block, first);
       else
-       {
-         if (!BB_VISITED (first))
-           bitmap_set_copy (ANTIC_OUT, maximal_set);
-         else
-           bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));
-       }
+       bitmap_set_copy (ANTIC_OUT, ANTIC_IN (first));

-      for (i = 1; VEC_iterate (basic_block, worklist, i, bprime); i++)
+      for (i = 0; VEC_iterate (basic_block, worklist, i, bprime); i++)
        {
          if (phi_nodes (bprime))
            {
              bitmap_set_t tmp = bitmap_set_new ();
-             bitmap_set_t from = ANTIC_IN (bprime);
-
-             if (!BB_VISITED (bprime))
-               from = maximal_set;
-             phi_translate_set (tmp, from, block, bprime);
+             phi_translate_set (tmp, ANTIC_IN (bprime), block, bprime);
              bitmap_set_and (ANTIC_OUT, tmp);
              bitmap_set_free (tmp);
            }
          else
-           {
-             if (!BB_VISITED (bprime))
-               bitmap_set_and (ANTIC_OUT, maximal_set);
-             else
-               bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
-           }
+           bitmap_set_and (ANTIC_OUT, ANTIC_IN (bprime));
        }
       VEC_free (basic_block, heap, worklist);
     }


Now obviously I'm not convinced we'll not defer blocks forever because
we can't seed one with the maximal set ...

Minimally tested with this testcase and tree-ssa.exp.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41101