incorporate a fix from smtcomp2010 version for handling CNF of (= bool bool); also make theoryOf(= t1 t2) return theoryOf(t1.getType()), rather than theoryOf(t1), as the latter gives different results for (= (geq x1 x2) (leq x2 x1)) and (= a (leq x2 x1)), which is strange and causes problems. should discuss at tuesday meeting. resolves bug 187.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/prop/cnf_stream.cpp b/src/prop/cnf_stream.cpp
index 9136a73c3..e95322348 100644
--- a/src/prop/cnf_stream.cpp
+++ b/src/prop/cnf_stream.cpp
@@ -364,6 +364,13 @@ SatLiteral TseitinCnfStream::toCNF(TNode node, bool negated) {
     case AND:
       nodeLit = handleAnd(node);
       break;
+    case EQUAL:
+      if(node[0].getType().isBoolean() && node[1].getType().isBoolean()) {
+        nodeLit = handleIff(node[0].iffNode(node[1]));
+      } else {
+        nodeLit = convertAtom(node);
+      }
+      break;
     default:
       {
         //TODO make sure this does not contain any boolean substructure