Update dfa.c.

2 files changed, 254 insertions, 129 deletions

diff --git a/support/ChangeLog b/support/ChangeLog
index d426f53e..09369826 100644
--- a/support/ChangeLog
+++ b/support/ChangeLog
@@ -1,3 +1,7 @@
+2018-10-22         Arnold D. Robbins     <arnold@skeeve.com>
+
+	* dfa.c: Update from GNULIB.
+
 2018-09-21         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* dfa.c, intprops.h: Sync from GNULIB.
diff --git a/support/dfa.c b/support/dfa.c
index 86eb677e..71c350e2 100644
--- a/support/dfa.c
+++ b/support/dfa.c
@@ -365,13 +365,6 @@ typedef struct
   ptrdiff_t alloc;              /* Number of elements allocated in ELEMS.  */
 } position_set;
 
-/* Sets of leaves are also stored as arrays.  */
-typedef struct
-{
-  size_t *elems;                /* Elements of this position set.  */
-  size_t nelem;                 /* Number of elements in this set.  */
-} leaf_set;
-
 /* A state of the dfa consists of a set of positions, some flags,
    and the token value of the lowest-numbered position of the state that
    contains an END token.  */
@@ -548,6 +541,12 @@ struct dfa
                                    string matching, but anchored to the
                                    beginning of the buffer.  */
 
+  /* Fields filled by dfaanalyze.  */
+  int *constraints;             /* Array of union of accepting constraints
+                                   in the follow of a position.  */
+  int *separates;               /* Array of contexts on follow of a
+                                   position.  */
+
   /* Fields filled by dfaexec.  */
   state_num tralloc;            /* Number of transition tables that have
                                    slots so far, not counting trans[-1] and
@@ -2083,7 +2082,7 @@ insert (position p, position_set *s)
   while (lo < hi)
     {
       ptrdiff_t mid = (lo + hi) >> 1;
-      if (s->elems[mid].index > p.index)
+      if (s->elems[mid].index < p.index)
         lo = mid + 1;
       else if (s->elems[mid].index == p.index)
         {
@@ -2101,6 +2100,14 @@ insert (position p, position_set *s)
   ++s->nelem;
 }
 
+static void
+append (position p, position_set *s)
+{
+  ptrdiff_t count = s->nelem;
+  s->elems = maybe_realloc (s->elems, count, &s->alloc, -1, sizeof *s->elems);
+  s->elems[s->nelem++] = p;
+}
+
 /* Merge S1 and S2 (with the additional constraint C2) into M.  The
    result is as if the positions of S1, and of S2 with the additional
    constraint C2, were inserted into an initially empty set.  */
@@ -2119,7 +2126,7 @@ merge_constrained (position_set const *s1, position_set const *s2,
   m->nelem = 0;
   while (i < s1->nelem || j < s2->nelem)
     if (! (j < s2->nelem)
-        || (i < s1->nelem && s1->elems[i].index >= s2->elems[j].index))
+        || (i < s1->nelem && s1->elems[i].index <= s2->elems[j].index))
       {
         unsigned int c = ((i < s1->nelem && j < s2->nelem
                            && s1->elems[i].index == s2->elems[j].index)
@@ -2172,7 +2179,7 @@ delete (size_t del, position_set *s)
   while (lo < hi)
     {
       size_t mid = (lo + hi) >> 1;
-      if (s->elems[mid].index > del)
+      if (s->elems[mid].index < del)
         lo = mid + 1;
       else if (s->elems[mid].index == del)
         {
@@ -2256,8 +2263,9 @@ state_index (struct dfa *d, position_set const *s, int context)
 
   for (state_num j = 0; j < s->nelem; j++)
     {
-      int c = s->elems[j].constraint;
-      if (d->tokens[s->elems[j].index] <= END)
+      int c = d->constraints[s->elems[j].index];
+
+      if (c != 0)
         {
           if (succeeds_in_context (c, context, CTX_ANY))
             constraint |= c;
@@ -2293,7 +2301,7 @@ state_index (struct dfa *d, position_set const *s, int context)
    constraint.  Repeat exhaustively until no funny positions are left.
    S->elems must be large enough to hold the result.  */
 static void
-epsclosure (position_set *initial, struct dfa const *d)
+epsclosure (struct dfa const *d)
 {
   position_set tmp;
   alloc_position_set (&tmp, d->nleaves);
@@ -2333,8 +2341,6 @@ epsclosure (position_set *initial, struct dfa const *d)
         for (size_t j = 0; j < d->tindex; j++)
           if (i != j && d->follows[j].nelem > 0)
             replace (&d->follows[j], i, &d->follows[i], constraint, &tmp);
-
-        replace (initial, i, &d->follows[i], constraint, &tmp);
       }
   free (tmp.elems);
 }
@@ -2367,17 +2373,12 @@ charclass_context (struct dfa const *dfa, charclass const *c)
    in the complement set will have the same follow set.  */
 
 static int _GL_ATTRIBUTE_PURE
-state_separate_contexts (position_set const *s)
+state_separate_contexts (struct dfa *d, position_set const *s)
 {
   int separate_contexts = 0;
 
   for (size_t j = 0; j < s->nelem; j++)
-    {
-      if (prev_newline_dependent (s->elems[j].constraint))
-        separate_contexts |= CTX_NEWLINE;
-      if (prev_letter_dependent (s->elems[j].constraint))
-        separate_contexts |= CTX_LETTER;
-    }
+    separate_contexts |= d->separates[s->elems[j].index];
 
   return separate_contexts;
 }
@@ -2402,77 +2403,165 @@ enum
   OPT_QUEUED = (1 << 4)
 };
 
-static ptrdiff_t
-merge_nfa_state (struct dfa *d, size_t *queue, ptrdiff_t nqueue, size_t tindex,
-                 char *flags, position_set *merged)
+static void
+merge_nfa_state (struct dfa *d, size_t tindex, char *flags,
+                 position_set *merged)
 {
   position_set *follows = d->follows;
   ptrdiff_t nelem = 0;
 
+  d->constraints[tindex] = 0;
+
   for (ptrdiff_t i = 0; i < follows[tindex].nelem; i++)
     {
-      size_t dindex = follows[tindex].elems[i].index;
+      size_t sindex = follows[tindex].elems[i].index;
 
       /* Skip the node as pruned in future.  */
       unsigned int iconstraint = follows[tindex].elems[i].constraint;
       if (iconstraint == 0)
         continue;
 
-      follows[tindex].elems[nelem++] = follows[tindex].elems[i];
-
-      if (tindex < dindex && !(flags[dindex] & OPT_QUEUED))
+      if (d->tokens[follows[tindex].elems[i].index] <= END)
         {
-          queue[nqueue++] = dindex;
-          flags[dindex] |= OPT_QUEUED;
+          d->constraints[tindex] |= follows[tindex].elems[i].constraint;
+          continue;
         }
 
-      if (flags[dindex] & (OPT_LPAREN | OPT_RPAREN))
-        continue;
-
-      for (ptrdiff_t j = i + 1; j < follows[tindex].nelem; j++)
+      if (!(flags[sindex] & (OPT_LPAREN | OPT_RPAREN)))
         {
-          size_t sindex = follows[tindex].elems[j].index;
+          ptrdiff_t j;
 
-          if (follows[tindex].elems[j].constraint != iconstraint)
-            continue;
+          for (j = 0; j < nelem; j++)
+            {
+              size_t dindex = follows[tindex].elems[j].index;
 
-          if (flags[sindex] & (OPT_LPAREN | OPT_RPAREN))
-            continue;
+              if (follows[tindex].elems[j].constraint != iconstraint)
+                continue;
 
-          if (d->tokens[sindex] != d->tokens[dindex])
-            continue;
+              if (flags[dindex] & (OPT_LPAREN | OPT_RPAREN))
+                continue;
 
-          if ((flags[sindex] ^ flags[dindex]) & OPT_REPEAT)
-            continue;
+              if (d->tokens[sindex] != d->tokens[dindex])
+                continue;
+
+              if ((flags[sindex] ^ flags[dindex]) & OPT_REPEAT)
+                continue;
 
-          if (flags[sindex] & OPT_REPEAT)
-            delete (sindex, &follows[sindex]);
+              if (flags[sindex] & OPT_REPEAT)
+                delete (sindex, &follows[sindex]);
 
-          merge2 (&follows[dindex], &follows[sindex], merged);
+              merge2 (&follows[dindex], &follows[sindex], merged);
 
-          /* Mark it as pruned in future.  */
-          follows[tindex].elems[j].constraint = 0;
+              break;
+            }
+
+          if (j < nelem)
+            continue;
         }
+
+      follows[tindex].elems[nelem++] = follows[tindex].elems[i];
+      flags[sindex] |= OPT_QUEUED;
     }
 
   follows[tindex].nelem = nelem;
+}
+
+static int
+compare (const void *a, const void *b)
+{
+  int aindex;
+  int bindex;
+
+  aindex = (int) ((position *) a)->index;
+  bindex = (int) ((position *) b)->index;
+
+  return aindex - bindex;
+}
+
+static void
+reorder_tokens (struct dfa *d)
+{
+  ptrdiff_t nleaves;
+  ptrdiff_t *map;
+  token *tokens;
+  position_set *follows;
+  int *constraints;
+  char *multibyte_prop;
+
+  nleaves = 0;
+
+  map = xnmalloc (d->tindex, sizeof *map);
+
+  map[0] = nleaves++;
+
+  for (ptrdiff_t i = 1; i < d->tindex; i++)
+    map[i] = -1;
+
+  tokens = xnmalloc (d->nleaves, sizeof *tokens);
+  follows = xnmalloc (d->nleaves, sizeof *follows);
+  constraints = xnmalloc (d->nleaves, sizeof *constraints);
+
+  if (d->localeinfo.multibyte)
+    multibyte_prop = xnmalloc (d->nleaves, sizeof *multibyte_prop);
+  else
+    multibyte_prop = NULL;
+
+  for (ptrdiff_t i = 0; i < d->tindex; i++)
+    {
+      if (map[i] == -1)
+        {
+          free (d->follows[i].elems);
+          d->follows[i].elems = NULL;
+          d->follows[i].nelem = 0;
+          continue;
+        }
+
+      tokens[map[i]] = d->tokens[i];
+      follows[map[i]] = d->follows[i];
+      constraints[map[i]] = d->constraints[i];
+
+      if (multibyte_prop != NULL)
+        multibyte_prop[map[i]] = d->multibyte_prop[i];
+
+      for (ptrdiff_t j = 0; j < d->follows[i].nelem; j++)
+        {
+          if (map[d->follows[i].elems[j].index] == -1)
+            map[d->follows[i].elems[j].index] = nleaves++;
+
+          d->follows[i].elems[j].index = map[d->follows[i].elems[j].index];
+        }
+
+      qsort (d->follows[i].elems, d->follows[i].nelem,
+             sizeof *d->follows[i].elems, compare);
+    }
+
+  for (ptrdiff_t i = 0; i < nleaves; i++)
+    {
+      d->tokens[i] = tokens[i];
+      d->follows[i] = follows[i];
+      d->constraints[i] = constraints[i];
+
+      if (multibyte_prop != NULL)
+        d->multibyte_prop[i] = multibyte_prop[i];
+    }
 
-  return nqueue;
+  d->tindex = d->nleaves = nleaves;
+
+  free (tokens);
+  free (follows);
+  free (constraints);
+  free (multibyte_prop);
+  free (map);
 }
 
 static void
 dfaoptimize (struct dfa *d)
 {
   char *flags;
-  size_t *queue;
-  ptrdiff_t nqueue;
   position_set merged0;
   position_set *merged;
-  ptrdiff_t extra_space = d->tindex + sizeof *queue - 1;
-  extra_space -= extra_space % sizeof *queue;
 
-  queue = xmalloc (d->nleaves * sizeof *queue + extra_space);
-  flags = (char *) (queue + d->nleaves);
+  flags = xmalloc (d->tindex * sizeof *flags);
   memset (flags, 0, d->tindex * sizeof *flags);
 
   for (size_t i = 0; i < d->tindex; i++)
@@ -2490,17 +2579,21 @@ dfaoptimize (struct dfa *d)
         }
     }
 
+  flags[0] |= OPT_QUEUED;
+
   merged = &merged0;
   alloc_position_set (merged, d->nleaves);
 
-  nqueue = 0;
-  queue[nqueue++] = 0;
+  d->constraints = xnmalloc (d->tindex, sizeof *d->constraints);
+
+  for (ptrdiff_t i = 0; i < d->tindex; i++)
+    if (flags[i] & OPT_QUEUED)
+      merge_nfa_state (d, i, flags, merged);
 
-  for (ptrdiff_t i = 0; i < nqueue; i++)
-    nqueue = merge_nfa_state (d, queue, nqueue, queue[i], flags, merged);
+  reorder_tokens (d);
 
   free (merged->elems);
-  free (queue);
+  free (flags);
 }
 
 /* Perform bottom-up analysis on the parse tree, computing various functions.
@@ -2561,8 +2654,10 @@ dfaanalyze (struct dfa *d, bool searchflag)
   /* Array allocated to hold position sets.  */
   position *posalloc = xnmalloc (d->nleaves, 2 * sizeof *posalloc);
   /* Firstpos and lastpos elements.  */
-  position *firstpos = posalloc + d->nleaves;
+  position *firstpos = posalloc;
   position *lastpos = firstpos + d->nleaves;
+  position pos;
+  position_set tmp;
 
   /* Stack for element counts and nullable flags.  */
   struct
@@ -2611,10 +2706,9 @@ dfaanalyze (struct dfa *d, bool searchflag)
           /* Every element in the firstpos of the argument is in the follow
              of every element in the lastpos.  */
           {
-            position_set tmp;
+            tmp.elems = firstpos - stk[-1].nfirstpos;
             tmp.nelem = stk[-1].nfirstpos;
-            tmp.elems = firstpos;
-            position *pos = lastpos;
+            position *pos = lastpos - stk[-1].nlastpos;
             for (size_t j = 0; j < stk[-1].nlastpos; j++)
               {
                 merge (&tmp, &d->follows[pos[j].index], &merged);
@@ -2632,10 +2726,9 @@ dfaanalyze (struct dfa *d, bool searchflag)
           /* Every element in the firstpos of the second argument is in the
              follow of every element in the lastpos of the first argument.  */
           {
-            position_set tmp;
             tmp.nelem = stk[-1].nfirstpos;
-            tmp.elems = firstpos;
-            position *pos = lastpos + stk[-1].nlastpos;
+            tmp.elems = firstpos - stk[-1].nfirstpos;
+            position *pos = lastpos - stk[-1].nlastpos - stk[-2].nlastpos;
             for (size_t j = 0; j < stk[-2].nlastpos; j++)
               {
                 merge (&tmp, &d->follows[pos[j].index], &merged);
@@ -2648,7 +2741,7 @@ dfaanalyze (struct dfa *d, bool searchflag)
           if (stk[-2].nullable)
             stk[-2].nfirstpos += stk[-1].nfirstpos;
           else
-            firstpos += stk[-1].nfirstpos;
+            firstpos -= stk[-1].nfirstpos;
 
           /* The lastpos of a CAT node is the lastpos of the second argument,
              union that of the first argument if the second is nullable.  */
@@ -2656,10 +2749,10 @@ dfaanalyze (struct dfa *d, bool searchflag)
             stk[-2].nlastpos += stk[-1].nlastpos;
           else
             {
-              position *pos = lastpos + stk[-2].nlastpos;
-              for (size_t j = stk[-1].nlastpos; j-- > 0;)
-                pos[j] = lastpos[j];
-              lastpos += stk[-2].nlastpos;
+              position *pos = lastpos - stk[-1].nlastpos - stk[-2].nlastpos;
+              for (size_t j = 0; j < stk[-1].nlastpos; j++)
+                pos[j] = pos[j + stk[-2].nlastpos];
+              lastpos -= stk[-2].nlastpos;
               stk[-2].nlastpos = stk[-1].nlastpos;
             }
 
@@ -2692,9 +2785,9 @@ dfaanalyze (struct dfa *d, bool searchflag)
           stk->nfirstpos = stk->nlastpos = 1;
           stk++;
 
-          --firstpos, --lastpos;
           firstpos->index = lastpos->index = i;
           firstpos->constraint = lastpos->constraint = NO_CONSTRAINT;
+          firstpos++, lastpos++;
 
           break;
         }
@@ -2706,33 +2799,37 @@ dfaanalyze (struct dfa *d, bool searchflag)
       fprintf (stderr,
                stk[-1].nullable ? " nullable: yes\n" : " nullable: no\n");
       fprintf (stderr, " firstpos:");
-      for (size_t j = stk[-1].nfirstpos; j-- > 0;)
+      for (size_t j = 0; j < stk[-1].nfirstpos; j++)
         {
-          fprintf (stderr, " %zu:", firstpos[j].index);
-          prtok (d->tokens[firstpos[j].index]);
+          fprintf (stderr, " %zu:", firstpos[j - stk[-1].nfirstpos].index);
+          prtok (d->tokens[firstpos[j - stk[-1].nfirstpos].index]);
         }
       fprintf (stderr, "\n lastpos:");
-      for (size_t j = stk[-1].nlastpos; j-- > 0;)
+      for (size_t j = 0; j < stk[-1].nlastpos; j++)
         {
-          fprintf (stderr, " %zu:", lastpos[j].index);
-          prtok (d->tokens[lastpos[j].index]);
+          fprintf (stderr, " %zu:", lastpos[j - stk[-1].nlastpos].index);
+          prtok (d->tokens[lastpos[j - stk[-1].nlastpos].index]);
         }
       putc ('\n', stderr);
 #endif
     }
 
+  /* For each follow set that is the follow set of a real position, replace
+     it with its epsilon closure.  */
+  epsclosure (d);
+
   dfaoptimize (d);
 
 #ifdef DEBUG
   for (size_t i = 0; i < d->tindex; ++i)
-    if (d->tokens[i] < NOTCHAR || d->tokens[i] == BACKREF
-        || d->tokens[i] == ANYCHAR || d->tokens[i] == MBCSET
-        || d->tokens[i] >= CSET)
+    if (d->tokens[i] == BEG || d->tokens[i] < NOTCHAR
+        || d->tokens[i] == BACKREF || d->tokens[i] == ANYCHAR
+        || d->tokens[i] == MBCSET || d->tokens[i] >= CSET)
       {
         fprintf (stderr, "follows(%zu:", i);
         prtok (d->tokens[i]);
         fprintf (stderr, "):");
-        for (size_t j = d->follows[i].nelem; j-- > 0;)
+        for (size_t j = 0; j < d->follows[i].nelem; j++)
           {
             fprintf (stderr, " %zu:", d->follows[i].elems[j].index);
             prtok (d->tokens[d->follows[i].elems[j].index]);
@@ -2742,26 +2839,50 @@ dfaanalyze (struct dfa *d, bool searchflag)
 #endif
 
 
-  /* For each follow set that is the follow set of a real position, replace
-     it with its epsilon closure.  */
-  epsclosure (&d->follows[0], d);
+  pos.index = 0;
+  pos.constraint = NO_CONSTRAINT;
+
+  alloc_position_set (&tmp, 1);
+
+  append (pos, &tmp);
+
+  d->separates = xnmalloc (d->tindex, sizeof *d->separates);
+
+  for (ptrdiff_t i = 0; i < d->tindex; i++)
+    {
+      d->separates[i] = 0;
+
+      if (prev_newline_dependent (d->constraints[i]))
+        d->separates[i] |= CTX_NEWLINE;
+      if (prev_letter_dependent (d->constraints[i]))
+        d->separates[i] |= CTX_LETTER;
+
+      for (ptrdiff_t j = 0; j < d->follows[i].nelem; j++)
+        {
+          if (prev_newline_dependent (d->follows[i].elems[j].constraint))
+            d->separates[i] |= CTX_NEWLINE;
+          if (prev_letter_dependent (d->follows[i].elems[j].constraint))
+            d->separates[i] |= CTX_LETTER;
+        }
+    }
 
   /* Context wanted by some position.  */
-  int separate_contexts = state_separate_contexts (&d->follows[0]);
+  int separate_contexts = state_separate_contexts (d, &tmp);
 
   /* Build the initial state.  */
   if (separate_contexts & CTX_NEWLINE)
-    state_index (d, &d->follows[0], CTX_NEWLINE);
+    state_index (d, &tmp, CTX_NEWLINE);
   d->initstate_notbol = d->min_trcount
-    = state_index (d, &d->follows[0], separate_contexts ^ CTX_ANY);
+    = state_index (d, &tmp, separate_contexts ^ CTX_ANY);
   if (separate_contexts & CTX_LETTER)
-    d->min_trcount = state_index (d, &d->follows[0], CTX_LETTER);
+    d->min_trcount = state_index (d, &tmp, CTX_LETTER);
   d->min_trcount++;
   d->trcount = 0;
 
   free (posalloc);
   free (stkalloc);
   free (merged.elems);
+  free (tmp.elems);
 }
 
 /* Make sure D's state arrays are large enough to hold NEW_STATE.  */
@@ -2835,7 +2956,9 @@ realloc_trans_if_necessary (struct dfa *d)
 static state_num
 build_state (state_num s, struct dfa *d, unsigned char uc)
 {
-  position_set follows;         /* Union of the follows of the group.  */
+  position_set follows;         /* Union of the follows for each
+                                   position of the current state.  */
+  position_set group;           /* Positions that match the input char.  */
   position_set tmp;             /* Temporary space for merging sets.  */
   state_num state;              /* New state.  */
   state_num state_newline;      /* New state on a newline transition.  */
@@ -2884,19 +3007,27 @@ build_state (state_num s, struct dfa *d, unsigned char uc)
   if (accepts_in_context (d->states[s].context, CTX_NONE, s, d))
     d->success[s] |= CTX_NONE;
 
+  alloc_position_set (&follows, d->nleaves);
+
+  /* Find the union of the follows of the positions of the group.
+     This is a hideously inefficient loop.  Fix it someday.  */
+  for (size_t j = 0; j < d->states[s].elems.nelem; ++j)
+    for (size_t k = 0;
+         k < d->follows[d->states[s].elems.elems[j].index].nelem; ++k)
+      insert (d->follows[d->states[s].elems.elems[j].index].elems[k],
+              &follows);
+
   /* Positions that match the input char.  */
-  leaf_set group;
-  group.elems = xnmalloc (d->nleaves, sizeof *group.elems);
-  group.nelem = 0;
+  alloc_position_set (&group, d->nleaves);
 
   /* The group's label.  */
   charclass label;
   fillset (&label);
 
-  for (size_t i = 0; i < d->states[s].elems.nelem; ++i)
+  for (size_t i = 0; i < follows.nelem; ++i)
     {
       charclass matches;            /* Set of matching characters.  */
-      position pos = d->states[s].elems.elems[i];
+      position pos = follows.elems[i];
       bool matched = false;
       if (d->tokens[pos.index] >= 0 && d->tokens[pos.index] < NOTCHAR)
         {
@@ -2927,10 +3058,8 @@ build_state (state_num s, struct dfa *d, unsigned char uc)
                                    CTX_NONE))
             {
               if (d->states[s].mbps.nelem == 0)
-                alloc_position_set (&d->states[s].mbps,
-                                    d->follows[pos.index].nelem);
-              for (size_t j = 0; j < d->follows[pos.index].nelem; j++)
-                insert (d->follows[pos.index].elems[j], &d->states[s].mbps);
+                alloc_position_set (&d->states[s].mbps, 1);
+              insert (pos, &d->states[s].mbps);
             }
         }
       else
@@ -2978,7 +3107,7 @@ build_state (state_num s, struct dfa *d, unsigned char uc)
         {
           for (size_t k = 0; k < CHARCLASS_WORDS; ++k)
             label.w[k] &= matches.w[k];
-          group.elems[group.nelem++] = pos.index;
+          append (pos, &group);
         }
       else
         {
@@ -2987,19 +3116,10 @@ build_state (state_num s, struct dfa *d, unsigned char uc)
         }
     }
 
-  alloc_position_set (&follows, d->nleaves);
   alloc_position_set (&tmp, d->nleaves);
 
   if (group.nelem > 0)
     {
-      follows.nelem = 0;
-
-      /* Find the union of the follows of the positions of the group.
-         This is a hideously inefficient loop.  Fix it someday.  */
-      for (size_t j = 0; j < group.nelem; ++j)
-        for (size_t k = 0; k < d->follows[group.elems[j]].nelem; ++k)
-          insert (d->follows[group.elems[j]].elems[k], &follows);
-
       /* If we are building a searching matcher, throw in the positions
          of state 0 as well, if possible.  */
       if (d->searchflag)
@@ -3025,35 +3145,31 @@ build_state (state_num s, struct dfa *d, unsigned char uc)
           if (!mergeit)
             {
               mergeit = true;
-              for (size_t j = 0; mergeit && j < follows.nelem; j++)
-                mergeit &= d->multibyte_prop[follows.elems[j].index];
+              for (size_t j = 0; mergeit && j < group.nelem; j++)
+                mergeit &= d->multibyte_prop[group.elems[j].index];
             }
           if (mergeit)
             {
-              merge (&d->states[0].elems, &follows, &tmp);
-              copy (&tmp, &follows);
+              merge (&d->states[0].elems, &group, &tmp);
+              copy (&tmp, &group);
             }
         }
 
       /* Find out if the new state will want any context information,
          by calculating possible contexts that the group can match,
          and separate contexts that the new state wants to know.  */
-      int possible_contexts = charclass_context (d, &label);
-      int separate_contexts = state_separate_contexts (&follows);
+      int separate_contexts = state_separate_contexts (d, &group);
 
       /* Find the state(s) corresponding to the union of the follows.  */
-      if (possible_contexts & ~separate_contexts)
-        state = state_index (d, &follows, separate_contexts ^ CTX_ANY);
-      else
-        state = -1;
-      if (separate_contexts & possible_contexts & CTX_NEWLINE)
-        state_newline = state_index (d, &follows, CTX_NEWLINE);
+      if (d->syntax.sbit[uc] & separate_contexts & CTX_NEWLINE)
+        state = state_index (d, &group, CTX_NEWLINE);
+      else if (d->syntax.sbit[uc] & separate_contexts & CTX_LETTER)
+        state = state_index (d, &group, CTX_LETTER);
       else
-        state_newline = state;
-      if (separate_contexts & possible_contexts & CTX_LETTER)
-        state_letter = state_index (d, &follows, CTX_LETTER);
-      else
-        state_letter = state;
+        state = state_index (d, &group, separate_contexts ^ CTX_ANY);
+
+      state_newline = state;
+      state_letter = state;
 
       /* Reallocate now, to reallocate any newline transition properly.  */
       realloc_trans_if_necessary (d);
@@ -3215,7 +3331,7 @@ transit_state (struct dfa *d, state_num s, unsigned char const **pp,
   else
     merge (&d->states[s1].mbps, &d->states[s].elems, &d->mb_follows);
 
-  int separate_contexts = state_separate_contexts (&d->mb_follows);
+  int separate_contexts = state_separate_contexts (d, &d->mb_follows);
   state_num s2 = state_index (d, &d->mb_follows, separate_contexts ^ CTX_ANY);
   realloc_trans_if_necessary (d);
 
@@ -3596,6 +3712,8 @@ dfassbuild (struct dfa *d)
   sup->superset = NULL;
   sup->states = NULL;
   sup->sindex = 0;
+  sup->constraints = NULL;
+  sup->separates = NULL;
   sup->follows = NULL;
   sup->tralloc = 0;
   sup->trans = NULL;
@@ -3699,6 +3817,9 @@ dfafree (struct dfa *d)
   if (d->localeinfo.multibyte)
     free_mbdata (d);
 
+  free (d->constraints);
+  free (d->separates);
+
   for (size_t i = 0; i < d->sindex; ++i)
     {
       free (d->states[i].elems.elems);