--- src/tables.c.orig	2012-01-13 16:04:30.000000000 -0800
+++ src/tables.c	2012-01-13 16:08:40.000000000 -0800
@@ -111,7 +111,9 @@
    computation equals to BASE_MINIMUM, later mapped to BASE_NINF to
    keep parser tables small.  */
 base_number base_ninf = 0;
-static base_number *pos = NULL;
+static char *pos_set = NULL;
+/* Boolean vector representing an integer set in the range
+   -nstates..table_size (as an upper bound) */
 
 static unsigned int *conflrow;
 unsigned int *conflict_table;
@@ -158,12 +160,14 @@
   conflict_table = xnrealloc (conflict_table, table_size,
 			      sizeof *conflict_table);
   check = xnrealloc (check, table_size, sizeof *check);
+  pos_set = xnrealloc (pos_set, nstates+table_size, sizeof *pos_set);
 
   for (/* Nothing. */; old_size < table_size; ++old_size)
     {
       table[old_size] = 0;
       conflict_table[old_size] = 0;
       check[old_size] = -1;
+      pos_set[nstates+old_size] = 0;
     }
 }
 
@@ -703,9 +707,8 @@
 	    ok = false;
 	}
 
-      for (k = 0; ok && k < vector; k++)
-	if (pos[k] == j)
-	  ok = false;
+      if (ok && pos_set[nstates+j])
+	ok = false;
 
       if (ok)
 	{
@@ -764,7 +767,7 @@
   int i;
 
   base = xnmalloc (nvectors, sizeof *base);
-  pos = xnmalloc (nentries, sizeof *pos);
+  pos_set = xcalloc (nstates+table_size, sizeof *pos_set);
   table = xcalloc (table_size, sizeof *table);
   conflict_table = xcalloc (table_size, sizeof *conflict_table);
   check = xnmalloc (table_size, sizeof *check);
@@ -790,7 +793,7 @@
 	/* Action of I were already coded for S.  */
 	place = base[s];
 
-      pos[i] = place;
+      pos_set[nstates+place] = 1; /*place now belongs to pos set*/
       base[order[i]] = place;
     }
 
@@ -798,7 +801,7 @@
   base_ninf = table_ninf_remap (base, nvectors, BASE_MINIMUM);
   table_ninf = table_ninf_remap (table, high + 1, ACTION_NUMBER_MINIMUM);
 
-  free (pos);
+  free (pos_set);
 }