From 27422b67e25c08bb0d08369baaf676aae742a13f Mon Sep 17 00:00:00 2001
From: trevor_hansen <trevor_hansen@e59a4935-1847-0410-ae03-e826735625c1>
Date: Sun, 11 Sep 2011 12:53:41 +0000
Subject: [PATCH] Improvement. Speedup checking for changes by just comparing
 the number of fixed bits.

git-svn-id: https://stp-fast-prover.svn.sourceforge.net/svnroot/stp-fast-prover/trunk/stp@1395 e59a4935-1847-0410-ae03-e826735625c1
---
 .../constantBitP/ConstantBitPropagation.cpp   | 26 +++++++------------
 .../constantBitP/ConstantBitPropagation.h     |  3 +++
 2 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/src/simplifier/constantBitP/ConstantBitPropagation.cpp b/src/simplifier/constantBitP/ConstantBitPropagation.cpp
index 2b929b8..217cee5 100644
--- a/src/simplifier/constantBitP/ConstantBitPropagation.cpp
+++ b/src/simplifier/constantBitP/ConstantBitPropagation.cpp
@@ -498,20 +498,19 @@ namespace simplifier
             }
 
           // get a copy of the current fixing from the cache.
-          FixedBits current = *getCurrentFixedBits(n);
+          int previousTop = getCurrentFixedBits(n)->countFixed();
 
           // get the current for the children.
-          vector<FixedBits> childrenFixedBits;
-          childrenFixedBits.reserve(n.GetChildren().size());
+          previousChildrenFixedCount.clear();
 
           // get a copy of the current fixing from the cache.
           for (unsigned i = 0; i < n.GetChildren().size(); i++)
             {
-              childrenFixedBits.push_back(*getCurrentFixedBits(n[i]));
+              previousChildrenFixedCount.push_back(getCurrentFixedBits(n[i])->countFixed());
             }
 
           // derive the new ones.
-          FixedBits newBits = *getUpdatedFixedBits(n);
+          int newCount = getUpdatedFixedBits(n)->countFixed();
 
           if (CONFLICT == status)
             return;
@@ -519,26 +518,19 @@ namespace simplifier
           // Not all transfer function update the status. But if they report NO_CHANGE. There really is no change.
           if (status != NO_CHANGE)
             {
-              if (!FixedBits::equals(newBits, current)) // has been a change.
+              if (newCount != previousTop) // has been a change.
                 {
-                  assert(FixedBits::updateOK(current,newBits));
-
-                  scheduleUp(n); // schedule everything that depends on n.
-                  if (debug_cBitProp_messages)
-                    {
-                      cerr << "Changed " << n.GetNodeNum() << "from:" << current << "to:" << newBits << endl;
-                    }
+                      assert(newCount >= previousTop);
+                      scheduleUp(n); // schedule everything that depends on n.
                 }
 
               for (unsigned i = 0; i < n.GetChildren().size(); i++)
                 {
-                  if (!FixedBits::equals(*getCurrentFixedBits(n[i]), childrenFixedBits[i]))
+                  if (getCurrentFixedBits(n[i])->countFixed() != previousChildrenFixedCount[i])
                     {
-                      assert(FixedBits::updateOK(childrenFixedBits[i], *getCurrentFixedBits(n[i])) );
-
                       if (debug_cBitProp_messages)
                         {
-                          cerr << "Changed: " << n[i].GetNodeNum() << " from:" << childrenFixedBits[i] << "to:"
+                          cerr << "Changed: " << n[i].GetNodeNum() << " from:" << previousChildrenFixedCount[i] << "to:"
                               << *getCurrentFixedBits(n[i]) << endl;
                         }
 
diff --git a/src/simplifier/constantBitP/ConstantBitPropagation.h b/src/simplifier/constantBitP/ConstantBitPropagation.h
index 6159c80..f5509d6 100644
--- a/src/simplifier/constantBitP/ConstantBitPropagation.h
+++ b/src/simplifier/constantBitP/ConstantBitPropagation.h
@@ -41,6 +41,9 @@ namespace simplifier
 
       bool topFixed;
 
+      // A vector that's reused.
+      vector< int > previousChildrenFixedCount;
+
       void
       printNodeWithFixings();
 
-- 
2.47.3