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/********************* */
/*! \file ite_removal.cpp
** \verbatim
** Original author: dejan
** Major contributors: mdeters
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief Removal of term ITEs
**
** Removal of term ITEs.
**/
#include <vector>
#include "util/ite_removal.h"
#include "theory/rewriter.h"
#include "expr/command.h"
using namespace CVC4;
using namespace std;
namespace CVC4 {
struct IteRewriteAttrTag {};
typedef expr::Attribute<IteRewriteAttrTag, Node> IteRewriteAttr;
void RemoveITE::run(std::vector<Node>& output) {
for (unsigned i = 0, i_end = output.size(); i < i_end; ++ i) {
output[i] = run(output[i], output);
}
}
Node RemoveITE::run(TNode node, std::vector<Node>& output) {
// Current node
Debug("ite") << "removeITEs(" << node << ")" << endl;
// The result may be cached already
Node cachedRewrite;
NodeManager *nodeManager = NodeManager::currentNM();
if(nodeManager->getAttribute(node, IteRewriteAttr(), cachedRewrite)) {
Debug("ite") << "removeITEs: in-cache: " << cachedRewrite << endl;
return cachedRewrite.isNull() ? Node(node) : cachedRewrite;
}
// If an ITE replace it
if(node.getKind() == kind::ITE) {
TypeNode nodeType = node.getType();
if(!nodeType.isBoolean()) {
// Make the skolem to represent the ITE
Node skolem = nodeManager->mkVar(nodeType);
if(Dump.isOn("declarations")) {
stringstream kss;
kss << Expr::setlanguage(Expr::setlanguage::getLanguage(Dump("declarations"))) << skolem;
string ks = kss.str();
Dump("declarations") << CommentCommand(ks + " is a variable introduced due to term-level ITE removal") << endl
<< DeclareFunctionCommand(ks, nodeType.toType()) << endl;
}
// The new assertion
Node newAssertion =
nodeManager->mkNode(kind::ITE, node[0], skolem.eqNode(node[1]),
skolem.eqNode(node[2]));
Debug("ite") << "removeITEs(" << node << ") => " << newAssertion << endl;
// Attach the skolem
nodeManager->setAttribute(node, IteRewriteAttr(), skolem);
// Remove ITEs from the new assertion, rewrite it and push it to the output
output.push_back(run(newAssertion, output));
// The representation is now the skolem
return skolem;
}
}
// If not an ITE, go deep
vector<Node> newChildren;
bool somethingChanged = false;
if(node.getMetaKind() == kind::metakind::PARAMETERIZED) {
newChildren.push_back(node.getOperator());
}
// Remove the ITEs from the children
for(TNode::const_iterator it = node.begin(), end = node.end(); it != end; ++it) {
Node newChild = run(*it, output);
somethingChanged |= (newChild != *it);
newChildren.push_back(newChild);
}
// If changes, we rewrite
if(somethingChanged) {
cachedRewrite = nodeManager->mkNode(node.getKind(), newChildren);
nodeManager->setAttribute(node, IteRewriteAttr(), cachedRewrite);
return cachedRewrite;
} else {
nodeManager->setAttribute(node, IteRewriteAttr(), Node::null());
return node;
}
}
}/* CVC4 namespace */
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