From: trevor_hansen <trevor_hansen@e59a4935-1847-0410-ae03-e826735625c1>
Date: Mon, 28 Mar 2011 00:34:44 +0000 (+0000)
Subject: Extra simplification rule for BVXOR.
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=b1c8325421c94d6bb539697ffac837b5b80ae350;p=francis%2Fstp.git

Extra simplification rule for BVXOR.

git-svn-id: https://stp-fast-prover.svn.sourceforge.net/svnroot/stp-fast-prover/trunk/stp@1241 e59a4935-1847-0410-ae03-e826735625c1
---

diff --git a/src/AST/NodeFactory/SimplifyingNodeFactory.cpp b/src/AST/NodeFactory/SimplifyingNodeFactory.cpp
index 6f24778..d638808 100644
--- a/src/AST/NodeFactory/SimplifyingNodeFactory.cpp
+++ b/src/AST/NodeFactory/SimplifyingNodeFactory.cpp
@@ -694,6 +694,13 @@ ASTNode SimplifyingNodeFactory::CreateTerm(Kind kind, unsigned int width,
 
                     if (children[0].isConstant() && CONSTANTBV::BitVector_is_empty(children[0].GetBVConst()))
                       result = children[1];
+
+                    if (children[1].isConstant() && CONSTANTBV::BitVector_is_full(children[1].GetBVConst()))
+                      result = NodeFactory::CreateTerm(BEEV::BVNEG, width, children[0]);
+
+                    if (children[0].isConstant() && CONSTANTBV::BitVector_is_full(children[0].GetBVConst()))
+                      result = NodeFactory::CreateTerm(BEEV::BVNEG, width, children[1]);
+
                   }
                 break;