* src/reduce.c (inaccessable_symbols): Fix a buglet: because of a

[bison.git] / src / reduce.c

diff --git a/src/reduce.c b/src/reduce.c
index 05d15d23297c198ac3f98ffdb7e1d4b7ba737e2e..58bf43ea41ee5a6a5ed82106483c61d3f6ec42c0 100644 (file)
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -57,15 +57,6 @@ static int nuseless_productions;
 static int nuseful_nonterminals;
 int nuseless_nonterminals;
 \f
-static int
-bits_size (bitset S)
-{
-  int i, count = 0;
-
-  BITSET_EXECUTE (S, 0, i, { ++count; });
-  return count;
-}
-\f
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |
 | then do subset tests against N0, but even for the C grammar the    |
@@ -81,10 +72,9 @@ useful_production (int i, bitset N0)
   /* A production is useful if all of the nonterminals in its appear
      in the set of useful nonterminals.  */
 
-  for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
-    if (ISVAR (n = *r))
-      if (!bitset_test (N0, n - ntokens))
-       return FALSE;
+  for (r = rules[i].rhs; *r >= 0; r++)
+    if (ISVAR (n = *r) && !bitset_test (N0, n - ntokens))
+      return FALSE;
   return TRUE;
 }
 
@@ -103,7 +93,6 @@ useless_nonterminals (void)
      set of all productions which have a RHS all in N.  */
 
   Np = bitset_create (nvars, BITSET_FIXED);
-  bitset_zero (Np);
 
 
   /* The set being computed is a set of nonterminals which can derive
@@ -125,17 +114,13 @@ useless_nonterminals (void)
   while (1)
     {
       bitset_copy (Np, N);
-      for (i = 1; i <= nrules; i++)
-       {
-         if (!bitset_test (P, i))
-           {
-             if (useful_production (i, N))
-               {
-                 bitset_set (Np, rules[i].lhs - ntokens);
-                 bitset_set (P, i);
-               }
-           }
-       }
+      for (i = 1; i < nrules + 1; i++)
+       if (!bitset_test (P, i)
+           && useful_production (i, N))
+         {
+           bitset_set (Np, rules[i].lhs - ntokens);
+           bitset_set (P, i);
+         }
       if (bitset_equal_p (N, Np))
        break;
       Ns = Np;
@@ -179,9 +164,7 @@ inaccessable_symbols (void)
      user can know.  */
 
   Vp = bitset_create (nsyms, BITSET_FIXED);
-  bitset_zero (Vp);
   Pp = bitset_create (nrules + 1, BITSET_FIXED);
-  bitset_zero (Pp);
 
   /* If the start symbol isn't useful, then nothing will be useful. */
   if (bitset_test (N, start_symbol - ntokens))
@@ -191,13 +174,13 @@ inaccessable_symbols (void)
       while (1)
        {
          bitset_copy (Vp, V);
-         for (i = 1; i <= nrules; i++)
+         for (i = 1; i < nrules + 1; i++)
            {
              if (!bitset_test (Pp, i)
                  && bitset_test (P, i)
                  && bitset_test (V, rules[i].lhs))
                {
-                 for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
+                 for (r = rules[i].rhs; *r >= 0; r++)
                    if (ISTOKEN (t = *r) || bitset_test (N, t - ntokens))
                      bitset_set (Vp, t);
                  bitset_set (Pp, i);
@@ -222,7 +205,7 @@ inaccessable_symbols (void)
   bitset_free (P);
   P = Pp;
 
-  nuseful_productions = bits_size (P);
+  nuseful_productions = bitset_count (P);
   nuseless_productions = nrules - nuseful_productions;
 
   nuseful_nonterminals = 0;
@@ -232,7 +215,7 @@ inaccessable_symbols (void)
   nuseless_nonterminals = nvars - nuseful_nonterminals;
 
   /* A token that was used in %prec should not be warned about.  */
-  for (i = 1; i < nrules; i++)
+  for (i = 1; i < nrules + 1; i++)
     if (rules[i].precsym != 0)
       bitset_set (V1, rules[i].precsym);
 }
@@ -258,7 +241,7 @@ reduce_grammar_tables (void)
 
        np = 0;
        ni = 0;
-       for (pn = 1; pn <= nrules; pn++)
+       for (pn = 1; pn < nrules + 1; pn++)
          if (bitset_test (P, pn))
            {
              np++;
@@ -269,10 +252,10 @@ reduce_grammar_tables (void)
                  rules[np].prec  = rules[pn].prec;
                  rules[np].assoc = rules[pn].assoc;
                  rules[np].rhs   = rules[pn].rhs;
-                 if (rules[np].rhs != ni)
+                 if (rules[np].rhs - ritem != ni)
                    {
-                     pi = rules[np].rhs;
-                     rules[np].rhs = ni;
+                     pi = rules[np].rhs - ritem;
+                     rules[np].rhs = ritem + ni;
                      while (ritem[pi] >= 0)
                        ritem[ni++] = ritem[pi++];
                      ritem[ni++] = -np;
@@ -298,7 +281,7 @@ reduce_grammar_tables (void)
   if (nuseless_productions > 0)
     {
       int pn;
-      for (pn = 1; pn <= nrules; pn++)
+      for (pn = 1; pn < nrules + 1; pn++)
        rules[pn].useful = bitset_test (P, pn);
     }
 }
@@ -339,7 +322,7 @@ nonterminals_reduce (void)
 
   /* Replace all symbol numbers in valid data structures.  */
 
-  for (i = 1; i <= nrules; i++)
+  for (i = 1; i < nrules + 1; i++)
     {
       rules[i].lhs = nontermmap[rules[i].lhs];
       if (ISVAR (rules[i].precsym))
@@ -395,13 +378,13 @@ reduce_output (FILE *out)
     {
       int i;
       fprintf (out, "%s\n\n", _("Useless rules:"));
-      for (i = 1; i <= nrules; i++)
+      for (i = 1; i < nrules + 1; i++)
        if (!rules[i].useful)
          {
            rule r;
            fprintf (out, "#%-4d  ", i - 1);
            fprintf (out, "%s:", symbols[rules[i].lhs]->tag);
-           for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
+           for (r = rules[i].rhs; *r >= 0; r++)
              fprintf (out, " %s", symbols[*r]->tag);
            fputs (";\n", out);
          }
@@ -428,28 +411,28 @@ dump_grammar (FILE *out)
   fprintf (out, "\n\n");
   fprintf (out, "Rules\n-----\n\n");
   fprintf (out, "Num (Prec, Assoc, Useful, Ritem Range) Lhs -> Rhs (Ritem range) [Num]\n");
-  for (i = 1; i <= nrules; i++)
+  for (i = 1; i < nrules + 1; i++)
     {
       int rhs_count = 0;
       /* Find the last RHS index in ritems. */
-      for (r = &ritem[rules[i].rhs]; *r >= 0; ++r)
+      for (r = rules[i].rhs; *r >= 0; ++r)
        ++rhs_count;
       fprintf (out, "%3d (%2d, %2d, %2d, %2d-%2d)   %2d ->",
               i - 1,
               rules[i].prec, rules[i].assoc, rules[i].useful,
-              rules[i].rhs, rules[i].rhs + rhs_count - 1,
+              rules[i].rhs - ritem, rules[i].rhs - ritem + rhs_count - 1,
               rules[i].lhs);
       /* Dumped the RHS. */
-      for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
+      for (r = rules[i].rhs; *r >= 0; r++)
        fprintf (out, "%3d", *r);
       fprintf (out, "  [%d]\n", -(*r) - 1);
     }
   fprintf (out, "\n\n");
   fprintf (out, "Rules interpreted\n-----------------\n\n");
-  for (i = 1; i <= nrules; i++)
+  for (i = 1; i < nrules + 1; i++)
     {
       fprintf (out, "%-5d  %s :", i, symbols[rules[i].lhs]->tag);
-      for (r = &ritem[rules[i].rhs]; *r >= 0; r++)
+      for (r = rules[i].rhs; *r >= 0; r++)
        fprintf (out, " %s", symbols[*r]->tag);
       fputc ('\n', out);
     }
@@ -499,19 +482,14 @@ reduce_grammar (void)
   /* Allocate the global sets used to compute the reduced grammar */
 
   N = bitset_create (nvars, BITSET_FIXED);
-  bitset_zero (N);
   P =  bitset_create (nrules + 1, BITSET_FIXED);
-  bitset_zero (P);
   V = bitset_create (nsyms, BITSET_FIXED);
-  bitset_zero (V);
   V1 = bitset_create (nsyms, BITSET_FIXED);
-  bitset_zero (V1);
 
   useless_nonterminals ();
   inaccessable_symbols ();
 
   reduced = (bool) (nuseless_nonterminals + nuseless_productions > 0);
-
   if (!reduced)
     return;