X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/ef0175024063536689906e706f83ee9a12af98e3..235892350f6547e5c6a350b85561eda14409a0b5:/lib/lbitset.c

diff --git a/lib/lbitset.c b/lib/lbitset.c
index 39e5b4e5..aa19f45d 100644
--- a/lib/lbitset.c
+++ b/lib/lbitset.c
@@ -1,10 +1,13 @@
 /* Functions to support link list bitsets.
-   Copyright (C) 2002 Free Software Foundation, Inc.
+
+   Copyright (C) 2002-2004, 2006, 2009-2012 Free Software Foundation,
+   Inc.
+
    Contributed by Michael Hayes (m.hayes@elec.canterbury.ac.nz).
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
@@ -13,16 +16,17 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+#include <config.h>
+
+#include "lbitset.h"
 
-#include "bbitset.h"
 #include "obstack.h"
+#include <stddef.h>
 #include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
 
 /* This file implements linked-list bitsets.  These bitsets can be of
    arbitrary length and are more efficient than arrays of bits for
@@ -37,11 +41,12 @@
 /* Number of words to use for each element.  The larger the value the
    greater the size of the cache and the shorter the time to find a given bit
    but the more memory wasted for sparse bitsets and the longer the time
-   to search for set bits.  */
+   to search for set bits.
+
+   The routines that dominate timing profiles are lbitset_elt_find
+   and lbitset_elt_link, especially when accessing the bits randomly.  */
 
-#ifndef LBITSET_ELT_WORDS
 #define LBITSET_ELT_WORDS 2
-#endif
 
 typedef bitset_word lbitset_word;
 
@@ -49,7 +54,7 @@ typedef bitset_word lbitset_word;
 
 /* Number of bits stored in each element.  */
 #define LBITSET_ELT_BITS \
-  ((unsigned) (LBITSET_ELT_WORDS * LBITSET_WORD_BITS))
+  ((unsigned int) (LBITSET_ELT_WORDS * LBITSET_WORD_BITS))
 
 /* Lbitset element.   We use an array of bits for each element.
    These are linked together in a doubly-linked list.  */
@@ -63,62 +68,20 @@ typedef struct lbitset_elt_struct
 lbitset_elt;
 
 
-/* Head of lbitset linked list.  */
-typedef struct lbitset_struct
-{
-  lbitset_elt *head;		/* First element in linked list.  */
-  lbitset_elt *tail;		/* Last element in linked list.  */
-}
-*lbitset;
-
-
-struct bitset_struct
-{
-  struct bbitset_struct b;
-  struct lbitset_struct l;
-};
-
-
 enum lbitset_find_mode
   { LBITSET_FIND, LBITSET_CREATE, LBITSET_SUBST };
 
-static lbitset_elt lbitset_zero_elts[3];	/* Elements of all zero bits.  */
+static lbitset_elt lbitset_zero_elts[3]; /* Elements of all zero bits.  */
 
 /* Obstack to allocate bitset elements from.  */
 static struct obstack lbitset_obstack;
-static int lbitset_obstack_init = 0;
+static bool lbitset_obstack_init = false;
 static lbitset_elt *lbitset_free_list;	/* Free list of bitset elements.  */
 
-static lbitset_elt *lbitset_elt_alloc PARAMS ((void));
-static lbitset_elt *lbitset_elt_calloc PARAMS ((void));
-static void lbitset_elt_link PARAMS ((bitset, lbitset_elt *));
-static void lbitset_elt_unlink PARAMS ((bitset, lbitset_elt *));
-static void lbitset_elt_free PARAMS ((lbitset_elt *));
-static lbitset_elt *lbitset_elt_find PARAMS ((bitset, bitset_windex,
-					      enum lbitset_find_mode));
-static int lbitset_elt_zero_p PARAMS ((lbitset_elt *));
-
-static void lbitset_prune PARAMS ((bitset, lbitset_elt *));
-static void lbitset_weed PARAMS ((bitset));
-static void lbitset_zero PARAMS ((bitset));
-static int lbitset_equal_p PARAMS ((bitset, bitset));
-static void lbitset_copy PARAMS ((bitset, bitset));
-static int lbitset_copy_compare PARAMS ((bitset, bitset));
-static void lbitset_set PARAMS ((bitset, bitset_bindex));
-static void lbitset_reset PARAMS ((bitset, bitset_bindex));
-static int lbitset_test PARAMS ((bitset, bitset_bindex));
-static int lbitset_size PARAMS ((bitset));
-static int lbitset_op1 PARAMS ((bitset, enum bitset_ops));
-static int lbitset_op2 PARAMS ((bitset, bitset, enum bitset_ops));
-static int lbitset_op3 PARAMS ((bitset, bitset, bitset, enum bitset_ops));
-static int lbitset_list PARAMS ((bitset, bitset_bindex *, bitset_bindex,
-				 bitset_bindex *));
-static int lbitset_reverse_list
-PARAMS ((bitset, bitset_bindex *, bitset_bindex, bitset_bindex *));
-static void lbitset_free PARAMS ((bitset));
-
-
-#define LBITSET_CURRENT1(X) (lbitset_elt *)((char *)(X) + ((char *)&(((lbitset_elt *)(X))->next) - (char *)&(((lbitset_elt *)(X))->words)))
+extern void debug_lbitset (bitset);
+
+#define LBITSET_CURRENT1(X) \
+  ((lbitset_elt *) (void *) ((char *) (X) - offsetof (lbitset_elt, words)))
 
 #define LBITSET_CURRENT(X) LBITSET_CURRENT1((X)->b.cdata)
 
@@ -127,7 +90,7 @@ static void lbitset_free PARAMS ((bitset));
 
 /* Allocate a lbitset element.  The bits are not cleared.  */
 static inline lbitset_elt *
-lbitset_elt_alloc ()
+lbitset_elt_alloc (void)
 {
   lbitset_elt *elt;
 
@@ -138,12 +101,9 @@ lbitset_elt_alloc ()
     }
   else
     {
-      /* We can't use gcc_obstack_init to initialize the obstack since
-	 print-rtl.c now calls bitset functions, and bitset is linked
-	 into the gen* functions.  */
       if (!lbitset_obstack_init)
 	{
-	  lbitset_obstack_init = 1;
+	  lbitset_obstack_init = true;
 
 	  /* Let particular systems override the size of a chunk.  */
 
@@ -161,15 +121,13 @@ lbitset_elt_alloc ()
 #define OBSTACK_CHUNK_FREE free
 #endif
 
-#if !defined(__GNUC__) || (__GNUC__ < 2)
+#if ! defined __GNUC__ || __GNUC__ < 2
 #define __alignof__(type) 0
 #endif
 
 	  obstack_specify_allocation (&lbitset_obstack, OBSTACK_CHUNK_SIZE,
 				      __alignof__ (lbitset_elt),
-				      (void *(*)PARAMS ((long)))
 				      OBSTACK_CHUNK_ALLOC,
-				      (void (*)PARAMS ((void *)))
 				      OBSTACK_CHUNK_FREE);
 	}
 
@@ -183,9 +141,9 @@ lbitset_elt_alloc ()
 }
 
 
-/* Allocate a lbitset element.  The bits are not cleared.  */
+/* Allocate a lbitset element.  The bits are cleared.  */
 static inline lbitset_elt *
-lbitset_elt_calloc ()
+lbitset_elt_calloc (void)
 {
   lbitset_elt *elt;
 
@@ -196,8 +154,7 @@ lbitset_elt_calloc ()
 
 
 static inline void
-lbitset_elt_free (elt)
-     lbitset_elt *elt;
+lbitset_elt_free (lbitset_elt *elt)
 {
   elt->next = lbitset_free_list;
   lbitset_free_list = elt;
@@ -206,9 +163,7 @@ lbitset_elt_free (elt)
 
 /* Unlink element ELT from bitset BSET.  */
 static inline void
-lbitset_elt_unlink (bset, elt)
-     bitset bset;
-     lbitset_elt *elt;
+lbitset_elt_unlink (bitset bset, lbitset_elt *elt)
 {
   lbitset_elt *next = elt->next;
   lbitset_elt *prev = elt->prev;
@@ -253,9 +208,7 @@ lbitset_elt_unlink (bset, elt)
 /* Cut the chain of bitset BSET before element ELT and free the
    elements.  */
 static inline void
-lbitset_prune (bset, elt)
-     bitset bset;
-     lbitset_elt *elt;
+lbitset_prune (bitset bset, lbitset_elt *elt)
 {
   lbitset_elt *next;
 
@@ -285,28 +238,25 @@ lbitset_prune (bset, elt)
 }
 
 
-/* Return nonzero if all bits in an element are zero.  */
-static inline int
-lbitset_elt_zero_p (elt)
-     lbitset_elt *elt;
+/* Are all bits in an element zero?  */
+static inline bool
+lbitset_elt_zero_p (lbitset_elt *elt)
 {
   int i;
 
   for (i = 0; i < LBITSET_ELT_WORDS; i++)
     if (elt->words[i])
-      return 0;
+      return false;
 
-  return 1;
+  return true;
 }
 
 
 /* Link the bitset element into the current bitset linked list.  */
 static inline void
-lbitset_elt_link (bset, elt)
-     bitset bset;
-     lbitset_elt *elt;
+lbitset_elt_link (bitset bset, lbitset_elt *elt)
 {
-  bitset_windex index = elt->index;
+  bitset_windex windex = elt->index;
   lbitset_elt *ptr;
   lbitset_elt *current;
 
@@ -325,10 +275,10 @@ lbitset_elt_link (bset, elt)
 
   /* If this index is less than that of the current element, it goes
      somewhere before the current element.  */
-  else if (index < bset->b.cindex)
+  else if (windex < bset->b.cindex)
     {
       for (ptr = current;
-	   ptr->prev && ptr->prev->index > index; ptr = ptr->prev)
+	   ptr->prev && ptr->prev->index > windex; ptr = ptr->prev)
 	continue;
 
       if (ptr->prev)
@@ -345,7 +295,7 @@ lbitset_elt_link (bset, elt)
   else
     {
       for (ptr = current;
-	   ptr->next && ptr->next->index < index; ptr = ptr->next)
+	   ptr->next && ptr->next->index < windex; ptr = ptr->next)
 	continue;
 
       if (ptr->next)
@@ -359,17 +309,15 @@ lbitset_elt_link (bset, elt)
     }
 
   /* Set up so this is the first element searched.  */
-  bset->b.cindex = index;
+  bset->b.cindex = windex;
   bset->b.csize = LBITSET_ELT_WORDS;
   bset->b.cdata = elt->words;
 }
 
 
 static lbitset_elt *
-lbitset_elt_find (bset, index, mode)
-     bitset bset;
-     bitset_windex index;
-     enum lbitset_find_mode mode;
+lbitset_elt_find (bitset bset, bitset_windex windex,
+		  enum lbitset_find_mode mode)
 {
   lbitset_elt *elt;
   lbitset_elt *current;
@@ -378,7 +326,7 @@ lbitset_elt_find (bset, index, mode)
     {
       current = LBITSET_CURRENT (bset);
       /* Check if element is the cached element.  */
-      if ((index - bset->b.cindex) < bset->b.csize)
+      if ((windex - bset->b.cindex) < bset->b.csize)
 	return current;
     }
   else
@@ -388,23 +336,23 @@ lbitset_elt_find (bset, index, mode)
 
   if (current)
     {
-      if (index < bset->b.cindex)
+      if (windex < bset->b.cindex)
 	{
 	  for (elt = current;
-	       elt->prev && elt->index > index; elt = elt->prev)
+	       elt->prev && elt->index > windex; elt = elt->prev)
 	    continue;
 	}
       else
 	{
 	  for (elt = current;
-	       elt->next && (elt->index + LBITSET_ELT_WORDS - 1) < index;
+	       elt->next && (elt->index + LBITSET_ELT_WORDS - 1) < windex;
 	       elt = elt->next)
 	    continue;
 	}
 
-      /* `element' is the nearest to the one we want.  If it's not the one
+      /* ELT is the nearest to the one we want.  If it's not the one
 	 we want, the one we want does not exist.  */
-      if (elt && (index - elt->index) < LBITSET_ELT_WORDS)
+      if (windex - elt->index < LBITSET_ELT_WORDS)
 	{
 	  bset->b.cindex = elt->index;
 	  bset->b.csize = LBITSET_ELT_WORDS;
@@ -415,30 +363,29 @@ lbitset_elt_find (bset, index, mode)
 
   switch (mode)
     {
+    default:
+      abort ();
+
     case LBITSET_FIND:
       return 0;
 
     case LBITSET_CREATE:
-      index = (index / (unsigned) LBITSET_ELT_WORDS) * LBITSET_ELT_WORDS;
+      windex -= windex % LBITSET_ELT_WORDS;
 
       elt = lbitset_elt_calloc ();
-      elt->index = index;
+      elt->index = windex;
       lbitset_elt_link (bset, elt);
       return elt;
 
     case LBITSET_SUBST:
       return &lbitset_zero_elts[0];
-
-    default:
-      abort ();
     }
 }
 
 
 /* Weed out the zero elements from the list.  */
 static inline void
-lbitset_weed (bset)
-     bitset bset;
+lbitset_weed (bitset bset)
 {
   lbitset_elt *elt;
   lbitset_elt *next;
@@ -453,9 +400,8 @@ lbitset_weed (bset)
 
 
 /* Set all bits in the bitset to zero.  */
-static inline void
-lbitset_zero (bset)
-     bitset bset;
+static void
+lbitset_zero (bitset bset)
 {
   lbitset_elt *head;
 
@@ -468,17 +414,16 @@ lbitset_zero (bset)
 }
 
 
-static inline int
-lbitset_equal_p (dst, src)
-     bitset dst;
-     bitset src;
+/* Is DST == SRC?  */
+static inline bool
+lbitset_equal_p (bitset dst, bitset src)
 {
   lbitset_elt *selt;
   lbitset_elt *delt;
   int j;
 
   if (src == dst)
-    return 1;
+    return true;
 
   lbitset_weed (src);
   lbitset_weed (dst);
@@ -486,11 +431,11 @@ lbitset_equal_p (dst, src)
        selt && delt; selt = selt->next, delt = delt->next)
     {
       if (selt->index != delt->index)
-	return 0;
+	return false;
 
       for (j = 0; j < LBITSET_ELT_WORDS; j++)
 	if (delt->words[j] != selt->words[j])
-	  return 0;
+	  return false;
     }
   return !selt && !delt;
 }
@@ -498,9 +443,7 @@ lbitset_equal_p (dst, src)
 
 /* Copy bits from bitset SRC to bitset DST.  */
 static inline void
-lbitset_copy (dst, src)
-     bitset dst;
-     bitset src;
+lbitset_copy (bitset dst, bitset src)
 {
   lbitset_elt *elt;
   lbitset_elt *head;
@@ -539,15 +482,13 @@ lbitset_copy (dst, src)
 }
 
 
-/* Copy bits from bitset SRC to bitset DST.  Return non-zero if
+/* Copy bits from bitset SRC to bitset DST.  Return true if
    bitsets different.  */
-static inline int
-lbitset_copy_compare (dst, src)
-     bitset dst;
-     bitset src;
+static inline bool
+lbitset_copy_cmp (bitset dst, bitset src)
 {
   if (src == dst)
-    return 0;
+    return false;
 
   if (!LBITSET_HEAD (dst))
     {
@@ -556,79 +497,66 @@ lbitset_copy_compare (dst, src)
     }
 
   if (lbitset_equal_p (dst, src))
-    return 0;
+    return false;
 
   lbitset_copy (dst, src);
-  return 1;
+  return true;
 }
 
 
-/* Return size in bits of bitset SRC.  */
-static int
-lbitset_size (src)
-     bitset src;
+static bitset_bindex
+lbitset_resize (bitset src, bitset_bindex size)
 {
-  lbitset_elt *elt;
-
-  elt = LBITSET_TAIL (src);
-  if (!elt)
-    return 0;
+    BITSET_NBITS_ (src) = size;
 
-  /* Return current size of bitset in bits.  */
-  return (elt->index + LBITSET_ELT_WORDS) * BITSET_WORD_BITS;
+    /* Need to prune any excess bits.  FIXME.  */
+    return size;
 }
 
-
 /* Set bit BITNO in bitset DST.  */
 static void
-lbitset_set (dst, bitno)
-     bitset dst;
-     bitset_bindex bitno;
+lbitset_set (bitset dst, bitset_bindex bitno)
 {
-  bitset_windex index = bitno / BITSET_WORD_BITS;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;
 
-  lbitset_elt_find (dst, index, LBITSET_CREATE);
+  lbitset_elt_find (dst, windex, LBITSET_CREATE);
 
-  dst->b.cdata[index - dst->b.cindex] |= (1 << (bitno % BITSET_WORD_BITS));
+  dst->b.cdata[windex - dst->b.cindex] |=
+    (bitset_word) 1 << (bitno % BITSET_WORD_BITS);
 }
 
 
 /* Reset bit BITNO in bitset DST.  */
 static void
-lbitset_reset (dst, bitno)
-     bitset dst;
-     bitset_bindex bitno;
+lbitset_reset (bitset dst, bitset_bindex bitno)
 {
-  bitset_windex index = bitno / BITSET_WORD_BITS;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;
 
-  if (!lbitset_elt_find (dst, index, LBITSET_FIND))
+  if (!lbitset_elt_find (dst, windex, LBITSET_FIND))
     return;
 
-  dst->b.cdata[index - dst->b.cindex] &= ~(1 << (bitno % BITSET_WORD_BITS));
+  dst->b.cdata[windex - dst->b.cindex] &=
+    ~((bitset_word) 1 << (bitno % BITSET_WORD_BITS));
 
   /* If all the data is zero, perhaps we should unlink it now...  */
 }
 
 
 /* Test bit BITNO in bitset SRC.  */
-static int
-lbitset_test (src, bitno)
-     bitset src;
-     bitset_bindex bitno;
+static bool
+lbitset_test (bitset src, bitset_bindex bitno)
 {
-  bitset_windex index = bitno / BITSET_WORD_BITS;
-
-  if (!lbitset_elt_find (src, index, LBITSET_FIND))
-    return 0;
+  bitset_windex windex = bitno / BITSET_WORD_BITS;
 
-  return (src->b.
-	  cdata[index - src->b.cindex] >> (bitno % BITSET_WORD_BITS)) & 1;
+  return (lbitset_elt_find (src, windex, LBITSET_FIND)
+	  && ((src->b.cdata[windex - src->b.cindex]
+	       >> (bitno % BITSET_WORD_BITS))
+	      & 1));
 }
 
 
 static void
-lbitset_free (bset)
-     bitset bset;
+lbitset_free (bitset bset)
 {
   lbitset_zero (bset);
 }
@@ -637,18 +565,15 @@ lbitset_free (bset)
 /* Find list of up to NUM bits set in BSET starting from and including
  *NEXT and store in array LIST.  Return with actual number of bits
  found and with *NEXT indicating where search stopped.  */
-static int
-lbitset_reverse_list (bset, list, num, next)
-     bitset bset;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+static bitset_bindex
+lbitset_list_reverse (bitset bset, bitset_bindex *list,
+		      bitset_bindex num, bitset_bindex *next)
 {
   bitset_bindex rbitno;
   bitset_bindex bitno;
-  unsigned int bitcnt;
-  bitset_bindex bitoff;
-  bitset_windex index;
+  unsigned int bcount;
+  bitset_bindex boffset;
+  bitset_windex windex;
   bitset_bindex count;
   lbitset_elt *elt;
   bitset_word word;
@@ -666,41 +591,52 @@ lbitset_reverse_list (bset, list, num, next)
 
   bitno = n_bits - (rbitno + 1);
 
-  index = bitno / BITSET_WORD_BITS;
+  windex = bitno / BITSET_WORD_BITS;
 
   /* Skip back to starting element.  */
-  for (; elt && elt->index > index; elt = elt->prev)
+  for (; elt && elt->index > windex; elt = elt->prev)
     continue;
 
   if (!elt)
     return 0;
 
-  /* If num is 1, we could speed things up with a binary search
-     of the word of interest.  */
+  if (windex >= elt->index + LBITSET_ELT_WORDS)
+    {
+      /* We are trying to start in no-mans land so start
+	 at end of current elt.  */
+      bcount = BITSET_WORD_BITS - 1;
+      windex = elt->index + LBITSET_ELT_WORDS - 1;
+    }
+  else
+    {
+      bcount = bitno % BITSET_WORD_BITS;
+    }
 
   count = 0;
-  bitcnt = bitno % BITSET_WORD_BITS;
-  bitoff = index * BITSET_WORD_BITS;
+  boffset = windex * BITSET_WORD_BITS;
+
+  /* If num is 1, we could speed things up with a binary search
+     of the word of interest.  */
 
   while (elt)
     {
       bitset_word *srcp = elt->words;
 
-      for (; (index - elt->index) < LBITSET_ELT_WORDS;
-	   index--, bitoff -= BITSET_WORD_BITS,
-	     bitcnt = BITSET_WORD_BITS - 1)
+      for (; (windex - elt->index) < LBITSET_ELT_WORDS;
+	   windex--, boffset -= BITSET_WORD_BITS,
+	     bcount = BITSET_WORD_BITS - 1)
 	{
 	  word =
-	    srcp[index - elt->index] << (BITSET_WORD_BITS - 1 - bitcnt);
+	    srcp[windex - elt->index] << (BITSET_WORD_BITS - 1 - bcount);
 
-	  for (; word; bitcnt--)
+	  for (; word; bcount--)
 	    {
 	      if (word & BITSET_MSB)
 		{
-		  list[count++] = bitoff + bitcnt;
+		  list[count++] = boffset + bcount;
 		  if (count >= num)
 		    {
-		      *next = n_bits - (bitoff + bitcnt);
+		      *next = n_bits - (boffset + bcount);
 		      return count;
 		    }
 		}
@@ -711,12 +647,12 @@ lbitset_reverse_list (bset, list, num, next)
       elt = elt->prev;
       if (elt)
 	{
-	  index = elt->index + LBITSET_ELT_WORDS - 1;
-	  bitoff = index * BITSET_WORD_BITS;
+	  windex = elt->index + LBITSET_ELT_WORDS - 1;
+	  boffset = windex * BITSET_WORD_BITS;
 	}
     }
 
-  *next = n_bits - (bitoff + 1);
+  *next = n_bits - (boffset + 1);
   return count;
 }
 
@@ -724,15 +660,12 @@ lbitset_reverse_list (bset, list, num, next)
 /* Find list of up to NUM bits set in BSET starting from and including
  *NEXT and store in array LIST.  Return with actual number of bits
  found and with *NEXT indicating where search stopped.  */
-static int
-lbitset_list (bset, list, num, next)
-     bitset bset;
-     bitset_bindex *list;
-     bitset_bindex num;
-     bitset_bindex *next;
+static bitset_bindex
+lbitset_list (bitset bset, bitset_bindex *list,
+	      bitset_bindex num, bitset_bindex *next)
 {
   bitset_bindex bitno;
-  bitset_windex index;
+  bitset_windex windex;
   bitset_bindex count;
   lbitset_elt *elt;
   lbitset_elt *head;
@@ -751,26 +684,26 @@ lbitset_list (bset, list, num, next)
 
       /* Start with the first element.  */
       elt = head;
-      index = elt->index;
-      bitno = index * BITSET_WORD_BITS;
+      windex = elt->index;
+      bitno = windex * BITSET_WORD_BITS;
     }
   else
     {
-      index = bitno / BITSET_WORD_BITS;
+      windex = bitno / BITSET_WORD_BITS;
 
       /* Skip to starting element.  */
       for (elt = head;
-	   elt && (elt->index + LBITSET_ELT_WORDS - 1) < index;
+	   elt && (elt->index + LBITSET_ELT_WORDS - 1) < windex;
 	   elt = elt->next)
 	continue;
 
       if (!elt)
 	return 0;
 
-      if (index < elt->index)
+      if (windex < elt->index)
 	{
-	  index = elt->index;
-	  bitno = index * BITSET_WORD_BITS;
+	  windex = elt->index;
+	  bitno = windex * BITSET_WORD_BITS;
 	}
       else
 	{
@@ -778,9 +711,9 @@ lbitset_list (bset, list, num, next)
 
 	  /* We are starting within an element.  */
 
-	  for (; (index - elt->index) < LBITSET_ELT_WORDS; index++)
+	  for (; (windex - elt->index) < LBITSET_ELT_WORDS; windex++)
 	    {
-	      word = srcp[index - elt->index] >> (bitno % BITSET_WORD_BITS);
+	      word = srcp[windex - elt->index] >> (bitno % BITSET_WORD_BITS);
 
 	      for (; word; bitno++)
 		{
@@ -795,14 +728,14 @@ lbitset_list (bset, list, num, next)
 		    }
 		  word >>= 1;
 		}
-	      bitno = (index + 1) * BITSET_WORD_BITS;
+	      bitno = (windex + 1) * BITSET_WORD_BITS;
 	    }
 
 	  elt = elt->next;
 	  if (elt)
 	    {
-	      index = elt->index;
-	      bitno = index * BITSET_WORD_BITS;
+	      windex = elt->index;
+	      bitno = windex * BITSET_WORD_BITS;
 	    }
 	}
     }
@@ -841,8 +774,8 @@ lbitset_list (bset, list, num, next)
 		  word >>= 1;
 		}
 	    }
-	  index++;
-	  bitno = index * BITSET_WORD_BITS;
+	  windex++;
+	  bitno = windex * BITSET_WORD_BITS;
 
 	  word = srcp[1];
 	  if (word)
@@ -859,8 +792,8 @@ lbitset_list (bset, list, num, next)
 		  word >>= 1;
 		}
 	    }
-	  index++;
-	  bitno = index * BITSET_WORD_BITS;
+	  windex++;
+	  bitno = windex * BITSET_WORD_BITS;
 #else
 	  for (i = 0; i < LBITSET_ELT_WORDS; i++)
 	    {
@@ -884,8 +817,8 @@ lbitset_list (bset, list, num, next)
 		      word >>= 1;
 		    }
 		}
-	      index++;
-	      bitno = index * BITSET_WORD_BITS;
+	      windex++;
+	      bitno = windex * BITSET_WORD_BITS;
 	    }
 #endif
 	}
@@ -909,16 +842,16 @@ lbitset_list (bset, list, num, next)
 		    }
 		  word >>= 1;
 		}
-	      index++;
-	      bitno = index * BITSET_WORD_BITS;
+	      windex++;
+	      bitno = windex * BITSET_WORD_BITS;
 	    }
 	}
 
       elt = elt->next;
       if (elt)
 	{
-	  index = elt->index;
-	  bitno = index * BITSET_WORD_BITS;
+	  windex = elt->index;
+	  bitno = windex * BITSET_WORD_BITS;
 	}
     }
 
@@ -927,260 +860,244 @@ lbitset_list (bset, list, num, next)
 }
 
 
-static int
-lbitset_op1 (dst, op)
-     bitset dst;
-     enum bitset_ops op;
+static bool
+lbitset_empty_p (bitset dst)
 {
-  unsigned int i;
-  bitset_windex index;
   lbitset_elt *elt;
+  lbitset_elt *next;
 
-  switch (op)
+  for (elt = LBITSET_HEAD (dst); elt; elt = next)
     {
-    case BITSET_OP_ZERO:
-      lbitset_zero (dst);
-      break;
+      next = elt->next;
+      if (!lbitset_elt_zero_p (elt))
+	return 0;
+      /* Weed as we go.  */
+      lbitset_elt_unlink (dst, elt);
+    }
+
+  return 1;
+}
+
+
+/* Ensure that any unused bits within the last element are clear.  */
+static inline void
+lbitset_unused_clear (bitset dst)
+{
+  unsigned int last_bit;
+  bitset_bindex n_bits;
+
+  n_bits = BITSET_SIZE_ (dst);
+  last_bit = n_bits % LBITSET_ELT_BITS;
+
+  if (last_bit)
+    {
+      lbitset_elt *elt;
+      bitset_windex windex;
+      bitset_word *srcp;
 
-    case BITSET_OP_ONES:
-      /* This is a decidedly unfriendly operation for a linked list
-	 bitset!   */
       elt = LBITSET_TAIL (dst);
-      /* Ignore empty set.  */
-      if (!elt)
-	return 0;
+      srcp = elt->words;
+      windex = n_bits / BITSET_WORD_BITS;
 
-      index = elt->index;
-      for (i = 0; i < index; i += LBITSET_ELT_WORDS)
-	{
-	  /* Create new elements if they cannot be found.  */
-	  elt = lbitset_elt_find (dst, i, LBITSET_CREATE);
-	  memset (elt->words, ~0, sizeof (elt->words));
-	}
-      break;
+      srcp[windex - elt->index] &= ((bitset_word) 1 << last_bit) - 1;
+      windex++;
 
-    case BITSET_OP_EMPTY_P:
-      lbitset_weed (dst);
-      if (LBITSET_HEAD (dst))
-	return 0;
-      break;
+      for (; (windex - elt->index) < LBITSET_ELT_WORDS; windex++)
+	srcp[windex - elt->index] = 0;
+    }
+}
 
-    default:
-      abort ();
+
+static void
+lbitset_ones (bitset dst)
+{
+  bitset_windex i;
+  bitset_windex windex;
+  lbitset_elt *elt;
+
+  /* This is a decidedly unfriendly operation for a linked list
+      bitset!  It makes a sparse bitset become dense.  An alternative
+      is to have a flag that indicates that the bitset stores the
+      complement of what it indicates.  */
+
+  windex = (BITSET_SIZE_ (dst) + BITSET_WORD_BITS - 1) / BITSET_WORD_BITS;
+
+  for (i = 0; i < windex; i += LBITSET_ELT_WORDS)
+    {
+      /* Create new elements if they cannot be found.  */
+      elt = lbitset_elt_find (dst, i, LBITSET_CREATE);
+      memset (elt->words, -1, sizeof (elt->words));
     }
 
-  return 1;
+  lbitset_unused_clear (dst);
 }
 
 
-static int
-lbitset_op2 (dst, src, op)
-     bitset dst;
-     bitset src;
-     enum bitset_ops op;
+static void
+lbitset_not (bitset dst, bitset src)
 {
-  lbitset_elt *elt;
   lbitset_elt *selt;
   lbitset_elt *delt;
-  unsigned int i;
+  bitset_windex i;
   unsigned int j;
-  bitset_windex index;
+  bitset_windex windex;
 
-  switch (op)
-    {
-    case BITSET_OP_COPY:
-      lbitset_copy (dst, src);
-      break;
+  windex = (BITSET_SIZE_ (dst) + BITSET_WORD_BITS - 1) / BITSET_WORD_BITS;
 
-    case BITSET_OP_NOT:
-      /* This is another unfriendly operation for a linked list
-	 bitset!  */
-      elt = LBITSET_TAIL (dst);
-      /* Ignore empty set.  */
-      if (!elt)
-	return 0;
+  for (i = 0; i < windex; i += LBITSET_ELT_WORDS)
+    {
+      /* Create new elements for dst if they cannot be found
+	 or substitute zero elements if src elements not found.  */
+      selt = lbitset_elt_find (src, i, LBITSET_SUBST);
+      delt = lbitset_elt_find (dst, i, LBITSET_CREATE);
 
-      index = elt->index;
-      for (i = 0; i < index; i += LBITSET_ELT_WORDS)
-	{
-	  /* Create new elements for dst if they cannot be found
-	     or substitute zero elements if src elements not found.  */
-	  selt = lbitset_elt_find (dst, i, LBITSET_SUBST);
-	  delt = lbitset_elt_find (dst, i, LBITSET_CREATE);
+      for (j = 0; j < LBITSET_ELT_WORDS; j++)
+	delt->words[j] = ~selt->words[j];
+    }
+  lbitset_unused_clear (dst);
+  lbitset_weed (dst);
+  return;
+}
 
-	  for (j = 0; j < LBITSET_ELT_WORDS; j++)
-	    delt->words[j] = ~selt->words[j];
-	}
-      lbitset_weed (dst);
-      break;
 
-      /* Return 1 if DST == SRC.  */
-    case BITSET_OP_EQUAL_P:
-      return lbitset_equal_p (dst, src);
-      break;
+/* Is DST == DST | SRC?  */
+static bool
+lbitset_subset_p (bitset dst, bitset src)
+{
+  lbitset_elt *selt;
+  lbitset_elt *delt;
+  unsigned int j;
 
-      /* Return 1 if DST == DST | SRC.  */
-    case BITSET_OP_SUBSET_P:
-      for (selt = LBITSET_HEAD (src), delt = LBITSET_HEAD (dst);
-	   selt || delt; selt = selt->next, delt = delt->next)
+  for (selt = LBITSET_HEAD (src), delt = LBITSET_HEAD (dst);
+       selt || delt; selt = selt->next, delt = delt->next)
+    {
+      if (!selt)
+	selt = &lbitset_zero_elts[0];
+      else if (!delt)
+	delt = &lbitset_zero_elts[0];
+      else if (selt->index != delt->index)
 	{
-	  if (!selt)
-	    selt = &lbitset_zero_elts[0];
-	  else if (!delt)
-	    delt = &lbitset_zero_elts[0];
-	  else if (selt->index != delt->index)
+	  if (selt->index < delt->index)
 	    {
-	      if (selt->index < delt->index)
-		{
-		  lbitset_zero_elts[2].next = delt;
-		  delt = &lbitset_zero_elts[2];
-		}
-	      else
-		{
-		  lbitset_zero_elts[1].next = selt;
-		  selt = &lbitset_zero_elts[1];
-		}
+	      lbitset_zero_elts[2].next = delt;
+	      delt = &lbitset_zero_elts[2];
+	    }
+	  else
+	    {
+	      lbitset_zero_elts[1].next = selt;
+	      selt = &lbitset_zero_elts[1];
 	    }
-
-	  for (j = 0; j < LBITSET_ELT_WORDS; j++)
-	    if (delt->words[j] != (selt->words[j] | delt->words[j]))
-	      return 0;
 	}
-      break;
 
-      /* Return 1 if DST & SRC == 0.  */
-    case BITSET_OP_DISJOINT_P:
-      for (selt = LBITSET_HEAD (src), delt = LBITSET_HEAD (dst);
-	   selt && delt; selt = selt->next, delt = delt->next)
+      for (j = 0; j < LBITSET_ELT_WORDS; j++)
+	if (delt->words[j] != (selt->words[j] | delt->words[j]))
+	  return false;
+    }
+  return true;
+}
+
+
+/* Is DST & SRC == 0?  */
+static bool
+lbitset_disjoint_p (bitset dst, bitset src)
+{
+  lbitset_elt *selt;
+  lbitset_elt *delt;
+  unsigned int j;
+
+  for (selt = LBITSET_HEAD (src), delt = LBITSET_HEAD (dst);
+       selt && delt; selt = selt->next, delt = delt->next)
+    {
+      if (selt->index != delt->index)
 	{
-	  if (selt->index != delt->index)
+	  if (selt->index < delt->index)
 	    {
-	      if (selt->index < delt->index)
-		{
-		  lbitset_zero_elts[2].next = delt;
-		  delt = &lbitset_zero_elts[2];
-		}
-	      else
-		{
-		  lbitset_zero_elts[1].next = selt;
-		  selt = &lbitset_zero_elts[1];
-		}
+	      lbitset_zero_elts[2].next = delt;
+	      delt = &lbitset_zero_elts[2];
 	    }
-
-	  for (j = 0; j < LBITSET_ELT_WORDS; j++)
-	    if (selt->words[j] & delt->words[j])
-	      return 0;
+	  else
+	    {
+	      lbitset_zero_elts[1].next = selt;
+	      selt = &lbitset_zero_elts[1];
+	    }
+	  /* Since the elements are different, there is no
+	     intersection of these elements.  */
+	  continue;
 	}
-      break;
 
-    default:
-      abort ();
+      for (j = 0; j < LBITSET_ELT_WORDS; j++)
+	if (selt->words[j] & delt->words[j])
+	  return false;
     }
-
-  return 1;
+  return true;
 }
 
 
-static int
-lbitset_op3 (dst, src1, src2, op)
-     bitset dst;
-     bitset src1;
-     bitset src2;
-     enum bitset_ops op;
+static bool
+lbitset_op3_cmp (bitset dst, bitset src1, bitset src2, enum bitset_ops op)
 {
   lbitset_elt *selt1 = LBITSET_HEAD (src1);
   lbitset_elt *selt2 = LBITSET_HEAD (src2);
   lbitset_elt *delt = LBITSET_HEAD (dst);
-  bitset_windex index1;
-  bitset_windex index2;
-  bitset_windex index;
+  bitset_windex windex1;
+  bitset_windex windex2;
+  bitset_windex windex;
   lbitset_elt *stmp1;
   lbitset_elt *stmp2;
   lbitset_elt *dtmp;
   bitset_word *srcp1;
   bitset_word *srcp2;
   bitset_word *dstp;
-  int changed = 0;
+  bool changed = false;
   unsigned int i;
 
-  /* Fast track common, simple cases.  */
-  if (!selt2)
-    {
-      if (op == BITSET_OP_AND)
-	{
-	  lbitset_weed (dst);
-	  changed = !LBITSET_HEAD (dst);
-	  lbitset_zero (dst);
-	  return changed;
-	}
-      else if (op == BITSET_OP_ANDN || op == BITSET_OP_OR
-	       || op == BITSET_OP_XOR)
-	{
-	  return lbitset_copy_compare (dst, src1);
-	}
-    }
-  else if (!selt1)
-    {
-      if (op == BITSET_OP_AND || op == BITSET_OP_ANDN)
-	{
-	  lbitset_weed (dst);
-	  changed = !LBITSET_HEAD (dst);
-	  lbitset_zero (dst);
-	  return changed;
-	}
-      else if (op == BITSET_OP_OR || op == BITSET_OP_XOR)
-	{
-	  return lbitset_copy_compare (dst, src2);
-	}
-    }
-
   LBITSET_HEAD (dst) = 0;
   dst->b.csize = 0;
 
-  index1 = (selt1) ? selt1->index : BITSET_INDEX_MAX;
-  index2 = (selt2) ? selt2->index : BITSET_INDEX_MAX;
+  windex1 = (selt1) ? selt1->index : BITSET_WINDEX_MAX;
+  windex2 = (selt2) ? selt2->index : BITSET_WINDEX_MAX;
 
   while (selt1 || selt2)
     {
       /* Figure out whether we need to substitute zero elements for
 	 missing links.  */
-      if (index1 == index2)
+      if (windex1 == windex2)
 	{
-	  index = index1;
+	  windex = windex1;
 	  stmp1 = selt1;
 	  stmp2 = selt2;
 	  selt1 = selt1->next;
-	  index1 = (selt1) ? selt1->index : BITSET_INDEX_MAX;
+	  windex1 = (selt1) ? selt1->index : BITSET_WINDEX_MAX;
 	  selt2 = selt2->next;
-	  index2 = (selt2) ? selt2->index : BITSET_INDEX_MAX;
+	  windex2 = (selt2) ? selt2->index : BITSET_WINDEX_MAX;
 	}
-      else if (index1 < index2)
+      else if (windex1 < windex2)
 	{
-	  index = index1;
+	  windex = windex1;
 	  stmp1 = selt1;
 	  stmp2 = &lbitset_zero_elts[0];
 	  selt1 = selt1->next;
-	  index1 = (selt1) ? selt1->index : BITSET_INDEX_MAX;
+	  windex1 = (selt1) ? selt1->index : BITSET_WINDEX_MAX;
 	}
       else
 	{
-	  index = index2;
+	  windex = windex2;
 	  stmp1 = &lbitset_zero_elts[0];
 	  stmp2 = selt2;
 	  selt2 = selt2->next;
-	  index2 = (selt2) ? selt2->index : BITSET_INDEX_MAX;
+	  windex2 = (selt2) ? selt2->index : BITSET_WINDEX_MAX;
 	}
 
       /* Find the appropriate element from DST.  Begin by discarding
 	 elements that we've skipped.  */
-      while (delt && delt->index < index)
+      while (delt && delt->index < windex)
 	{
-	  changed = 1;
+	  changed = true;
 	  dtmp = delt;
 	  delt = delt->next;
 	  lbitset_elt_free (dtmp);
 	}
-      if (delt && delt->index == index)
+      if (delt && delt->index == windex)
 	{
 	  dtmp = delt;
 	  delt = delt->next;
@@ -1195,6 +1112,9 @@ lbitset_op3 (dst, src1, src2, op)
       dstp = dtmp->words;
       switch (op)
 	{
+	default:
+	  abort ();
+
 	case BITSET_OP_OR:
 	  for (i = 0; i < LBITSET_ELT_WORDS; i++, dstp++)
 	    {
@@ -1202,7 +1122,7 @@ lbitset_op3 (dst, src1, src2, op)
 
 	      if (*dstp != tmp)
 		{
-		  changed = 1;
+		  changed = true;
 		  *dstp = tmp;
 		}
 	    }
@@ -1215,7 +1135,7 @@ lbitset_op3 (dst, src1, src2, op)
 
 	      if (*dstp != tmp)
 		{
-		  changed = 1;
+		  changed = true;
 		  *dstp = tmp;
 		}
 	    }
@@ -1228,7 +1148,7 @@ lbitset_op3 (dst, src1, src2, op)
 
 	      if (*dstp != tmp)
 		{
-		  changed = 1;
+		  changed = true;
 		  *dstp = tmp;
 		}
 	    }
@@ -1241,32 +1161,16 @@ lbitset_op3 (dst, src1, src2, op)
 
 	      if (*dstp != tmp)
 		{
-		  changed = 1;
-		  *dstp = tmp;
-		}
-	    }
-	  break;
-
-	case BITSET_OP_ORN:
-	  for (i = 0; i < LBITSET_ELT_WORDS; i++, dstp++)
-	    {
-	      bitset_word tmp = *srcp1++ | ~(*srcp2++);
-
-	      if (*dstp != tmp)
-		{
-		  changed = 1;
+		  changed = true;
 		  *dstp = tmp;
 		}
 	    }
 	  break;
-
-	default:
-	  abort ();
 	}
 
       if (!lbitset_elt_zero_p (dtmp))
 	{
-	  dtmp->index = index;
+	  dtmp->index = windex;
 	  /* Perhaps this could be optimised...  */
 	  lbitset_elt_link (dst, dtmp);
 	}
@@ -1279,7 +1183,7 @@ lbitset_op3 (dst, src1, src2, op)
   /* If we have elements of DST left over, free them all.  */
   if (delt)
     {
-      changed = 1;
+      changed = true;
       lbitset_prune (dst, delt);
     }
 
@@ -1287,51 +1191,211 @@ lbitset_op3 (dst, src1, src2, op)
 }
 
 
+static bool
+lbitset_and_cmp (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_elt *selt1 = LBITSET_HEAD (src1);
+  lbitset_elt *selt2 = LBITSET_HEAD (src2);
+  bool changed;
+
+  if (!selt2)
+    {
+      lbitset_weed (dst);
+      changed = !LBITSET_HEAD (dst);
+      lbitset_zero (dst);
+      return changed;
+    }
+  else if (!selt1)
+    {
+      lbitset_weed (dst);
+      changed = !LBITSET_HEAD (dst);
+      lbitset_zero (dst);
+      return changed;
+    }
+  return lbitset_op3_cmp (dst, src1, src2, BITSET_OP_AND);
+}
+
+
+static void
+lbitset_and (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_and_cmp (dst, src1, src2);
+}
+
+
+static bool
+lbitset_andn_cmp (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_elt *selt1 = LBITSET_HEAD (src1);
+  lbitset_elt *selt2 = LBITSET_HEAD (src2);
+  bool changed;
+
+  if (!selt2)
+    {
+      return lbitset_copy_cmp (dst, src1);
+    }
+  else if (!selt1)
+    {
+      lbitset_weed (dst);
+      changed = !LBITSET_HEAD (dst);
+      lbitset_zero (dst);
+      return changed;
+    }
+  return lbitset_op3_cmp (dst, src1, src2, BITSET_OP_ANDN);
+}
+
+
+static void
+lbitset_andn (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_andn_cmp (dst, src1, src2);
+}
+
+
+static bool
+lbitset_or_cmp (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_elt *selt1 = LBITSET_HEAD (src1);
+  lbitset_elt *selt2 = LBITSET_HEAD (src2);
+
+  if (!selt2)
+    {
+      return lbitset_copy_cmp (dst, src1);
+    }
+  else if (!selt1)
+    {
+      return lbitset_copy_cmp (dst, src2);
+    }
+  return lbitset_op3_cmp (dst, src1, src2, BITSET_OP_OR);
+}
+
+
+static void
+lbitset_or (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_or_cmp (dst, src1, src2);
+}
+
+
+static bool
+lbitset_xor_cmp (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_elt *selt1 = LBITSET_HEAD (src1);
+  lbitset_elt *selt2 = LBITSET_HEAD (src2);
+
+  if (!selt2)
+    {
+      return lbitset_copy_cmp (dst, src1);
+    }
+  else if (!selt1)
+    {
+      return lbitset_copy_cmp (dst, src2);
+    }
+  return lbitset_op3_cmp (dst, src1, src2, BITSET_OP_XOR);
+}
+
+
+static void
+lbitset_xor (bitset dst, bitset src1, bitset src2)
+{
+  lbitset_xor_cmp (dst, src1, src2);
+}
+
+
+
 /* Vector of operations for linked-list bitsets.  */
-struct bitset_ops_struct lbitset_ops = {
+struct bitset_vtable lbitset_vtable = {
   lbitset_set,
   lbitset_reset,
+  bitset_toggle_,
   lbitset_test,
-  lbitset_size,
-  lbitset_op1,
-  lbitset_op2,
-  lbitset_op3,
-  bitset_op4,
+  lbitset_resize,
+  bitset_size_,
+  bitset_count_,
+  lbitset_empty_p,
+  lbitset_ones,
+  lbitset_zero,
+  lbitset_copy,
+  lbitset_disjoint_p,
+  lbitset_equal_p,
+  lbitset_not,
+  lbitset_subset_p,
+  lbitset_and,
+  lbitset_and_cmp,
+  lbitset_andn,
+  lbitset_andn_cmp,
+  lbitset_or,
+  lbitset_or_cmp,
+  lbitset_xor,
+  lbitset_xor_cmp,
+  bitset_and_or_,
+  bitset_and_or_cmp_,
+  bitset_andn_or_,
+  bitset_andn_or_cmp_,
+  bitset_or_and_,
+  bitset_or_and_cmp_,
   lbitset_list,
-  lbitset_reverse_list,
+  lbitset_list_reverse,
   lbitset_free,
   BITSET_LIST
 };
 
 
 /* Return size of initial structure.  */
-int
-lbitset_bytes (n_bits)
-     bitset_bindex n_bits ATTRIBUTE_UNUSED;
+size_t
+lbitset_bytes (bitset_bindex n_bits ATTRIBUTE_UNUSED)
 {
-  return sizeof (struct bitset_struct);
+  return sizeof (struct lbitset_struct);
 }
 
 
 /* Initialize a bitset.  */
-
 bitset
-lbitset_init (bset, n_bits)
-     bitset bset;
-     bitset_bindex n_bits ATTRIBUTE_UNUSED;
+lbitset_init (bitset bset, bitset_bindex n_bits ATTRIBUTE_UNUSED)
 {
-  bset->b.ops = &lbitset_ops;
+  BITSET_NBITS_ (bset) = n_bits;
+  bset->b.vtable = &lbitset_vtable;
   return bset;
 }
 
 
 void
-lbitset_release_memory ()
+lbitset_release_memory (void)
 {
   lbitset_free_list = 0;
   if (lbitset_obstack_init)
     {
-      lbitset_obstack_init = 0;
+      lbitset_obstack_init = false;
       obstack_free (&lbitset_obstack, NULL);
     }
 }
+
+
+/* Function to be called from debugger to debug lbitset.  */
+void
+debug_lbitset (bitset bset)
+{
+  lbitset_elt *elt;
+  unsigned int i;
+
+  if (!bset)
+    return;
+
+  for (elt = LBITSET_HEAD (bset); elt; elt = elt->next)
+    {
+      fprintf (stderr, "Elt %lu\n", (unsigned long int) elt->index);
+      for (i = 0; i < LBITSET_ELT_WORDS; i++)
+	{
+	  unsigned int j;
+	  bitset_word word;
+
+	  word = elt->words[i];
+
+	  fprintf (stderr, "  Word %u:", i);
+	  for (j = 0; j < LBITSET_WORD_BITS; j++)
+	    if ((word & ((bitset_word) 1 << j)))
+	      fprintf (stderr, " %u", j);
+	  fprintf (stderr, "\n");
+	}
+    }
+}