From 760b53a84bfc0c79bac266414136936400769e33 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim@epita.fr>
Date: Fri, 30 Nov 2001 10:48:14 +0000
Subject: [PATCH] * src/reduce.c (nonterminals_reduce): Instead of throwing
 away useless nonterminals, move them at the end of the symbol arrays.
 (reduce_output): Adjust. * tests/reduce.at (Useless Nonterminals): Adjust.

---
 ChangeLog       |  7 +++++++
 src/reduce.c    | 45 ++++++++++++++++++++++++++++-----------------
 tests/reduce.at |  6 ++++--
 3 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 1606c8dd..afc46aa4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2001-11-30  Akim Demaille  <akim@epita.fr>
+
+	* src/reduce.c (nonterminals_reduce): Instead of throwing away
+	useless nonterminals, move them at the end of the symbol arrays.
+	(reduce_output): Adjust.
+	* tests/reduce.at (Useless Nonterminals): Adjust.
+
 2001-11-30  Akim Demaille  <akim@epita.fr>
 
 	* src/reduce.c: Various comment/formatting changes.
diff --git a/src/reduce.c b/src/reduce.c
index 911fb929..7e164c50 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -342,26 +342,38 @@ nonterminals_reduce (void)
      in the map means it was useless and is being eliminated.  */
 
   short *nontermmap = XCALLOC (short, nvars) - ntokens;
-  for (i = ntokens; i < nsyms; i++)
-    nontermmap[i] = -1;
-
   n = ntokens;
   for (i = ntokens; i < nsyms; i++)
     if (BITISSET (V, i))
       nontermmap[i] = n++;
+  for (i = ntokens; i < nsyms; i++)
+    if (!BITISSET (V, i))
+      nontermmap[i] = n++;
 
-  /* Shuffle elements of tables indexed by symbol number.  */
 
-  for (i = ntokens; i < nsyms; i++)
-    {
-      n = nontermmap[i];
-      if (n >= 0)
-	{
-	  sassoc[n] = sassoc[i];
-	  sprec[n] = sprec[i];
-	  tags[n] = tags[i];
-	}
-    }
+  /* Shuffle elements of tables indexed by symbol number.  */
+  {
+    short *sassoc_sorted = XMALLOC (short, nvars) - ntokens;
+    short *sprec_sorted  = XMALLOC (short, nvars) - ntokens;
+    char **tags_sorted   = XMALLOC (char *, nvars) - ntokens;
+
+    for (i = ntokens; i < nsyms; i++)
+      {
+	n = nontermmap[i];
+	sassoc_sorted[n] = sassoc[i];
+	sprec_sorted[n]  = sprec[i];
+	tags_sorted[n]   = tags[i];
+      }
+    for (i = ntokens; i < nsyms; i++)
+      {
+	sassoc[i] = sassoc_sorted[i];
+	sprec[i]  = sprec_sorted[i];
+	tags[i]   = tags_sorted[i];
+      }
+    free (sassoc_sorted + ntokens);
+    free (sprec_sorted + ntokens);
+    free (tags_sorted + ntokens);
+  }
 
   /* Replace all symbol numbers in valid data structures.  */
 
@@ -403,9 +415,8 @@ reduce_output (FILE *out)
     {
       fprintf (out, _("Useless nonterminals:"));
       fprintf (out, "\n\n");
-      for (i = ntokens; i < nsyms; i++)
-	if (!BITISSET (V, i))
-	  fprintf (out, "   %s\n", tags[i]);
+      for (i = 0; i < nuseless_nonterminals; ++i)
+	fprintf (out, "   %s\n", tags[nsyms + i]);
     }
   b = FALSE;
   for (i = 0; i < ntokens; i++)
diff --git a/tests/reduce.at b/tests/reduce.at
index ed3a5150..08601d50 100644
--- a/tests/reduce.at
+++ b/tests/reduce.at
@@ -88,10 +88,12 @@ AT_DATA([[input.y]],
 exp: useful;
 ]])
 
-AT_CHECK([[bison input.y]])
+AT_CHECK([[bison input.y]], 0, [],
+[[input.y contains 9 useless nonterminals
+]])
 
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
-[[Terminals which are not used:
+[[Useless nonterminals:
    useless1
    useless2
    useless3
-- 
2.45.2