re PR tree-optimization/16954 (ICE in get_tmt_for with IMA and incomplete structs)

2004-09-24  Andrew Pinski  <pinskia@physics.uc.edu>

        PR tree-opt/16954
        * tree-ssa-copyrename.c (copy_rename_partition_coalesce):
        Prevent renaming if the aliasing sets of the type which the
        pointer points to are different.

From-SVN: r88064

gcc/ChangeLog

+2004-09-24  Andrew Pinski  <pinskia@physics.uc.edu>
+
+	PR tree-opt/16954
+	* tree-ssa-copyrename.c (copy_rename_partition_coalesce):
+	Prevent renaming if the aliasing sets of the type which the
+	pointer points to are different.
+
 2004-09-24  Joseph S. Myers  <jsm@polyomino.org.uk>
 
 	PR c/17188

gcc/tree-ssa-copyrename.c

@@ -261,6 +261,18 @@ copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
       return;
     }
 
+  /* Don't coalesce if the aliasing sets of the types are different.  */
+  if (POINTER_TYPE_P (TREE_TYPE (root1))
+      && POINTER_TYPE_P (TREE_TYPE (root2))
+      && get_alias_set (TREE_TYPE (TREE_TYPE (root1)))
+          != get_alias_set (TREE_TYPE (TREE_TYPE (root2))))
+    {
+      if (debug)
+	fprintf (debug, " : 2 different alasing sets. No coalesce.\n");
+      return;
+    }
+
+
   /* Merge the two partitions.  */
   p3 = partition_union (map->var_partition, p1, p2);