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/********************* */
/*! \file ite_simplifier.h
** \verbatim
** Original author: barrett
** Major contributors:
** Minor contributors (to current version):
** 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 Simplifications for ITE expressions
**
** This module implements preprocessing phases designed to simplify ITE
** expressions. Based on:
** Kim, Somenzi, Jin. Efficient Term-ITE Conversion for SMT. FMCAD 2009.
** Burch, Jerry. Techniques for Verifying Superscalar Microprocessors. DAC '96
**/
#include "cvc4_private.h"
#ifndef __CVC4__ITE_SIMPLIFIER_H
#define __CVC4__ITE_SIMPLIFIER_H
#include <deque>
#include <vector>
#include <utility>
#include "expr/node.h"
#include "expr/command.h"
#include "prop/prop_engine.h"
#include "context/cdhashset.h"
#include "theory/theory.h"
#include "theory/substitutions.h"
#include "theory/rewriter.h"
#include "theory/substitutions.h"
#include "theory/shared_terms_database.h"
#include "theory/term_registration_visitor.h"
#include "theory/valuation.h"
#include "util/stats.h"
#include "util/hash.h"
#include "util/cache.h"
#include "util/ite_removal.h"
namespace CVC4 {
class ITESimplifier {
Node d_true;
Node d_false;
std::hash_map<Node, bool, NodeHashFunction> d_containsTermITECache;
bool containsTermITE(TNode e);
std::hash_map<Node, bool, NodeHashFunction> d_leavesConstCache;
bool leavesAreConst(TNode e, theory::TheoryId tid);
bool leavesAreConst(TNode e)
{ return leavesAreConst(e, theory::Theory::theoryOf(e)); }
typedef std::hash_map<Node, Node, NodeHashFunction> NodeMap;
typedef std::hash_map<TNode, Node, TNodeHashFunction> TNodeMap;
typedef std::pair<Node, Node> NodePair;
struct NodePairHashFunction {
size_t operator () (const NodePair& pair) const {
size_t hash = 0;
hash = 0x9e3779b9 + NodeHashFunction().operator()(pair.first);
hash ^= 0x9e3779b9 + NodeHashFunction().operator()(pair.second) + (hash << 6) + (hash >> 2);
return hash;
}
};
typedef std::hash_map<NodePair, Node, NodePairHashFunction> NodePairMap;
NodePairMap d_simpConstCache;
Node simpConstants(TNode simpContext, TNode iteNode, TNode simpVar);
std::hash_map<TypeNode, Node, TypeNode::HashFunction> d_simpVars;
Node getSimpVar(TypeNode t);
NodeMap d_simpContextCache;
Node createSimpContext(TNode c, Node& iteNode, Node& simpVar);
Node simpITEAtom(TNode atom);
NodeMap d_simpITECache;
public:
Node simpITE(TNode assertion);
private:
class CareSetPtr;
class CareSetPtrVal {
friend class ITESimplifier::CareSetPtr;
ITESimplifier& d_iteSimplifier;
unsigned d_refCount;
std::set<Node> d_careSet;
CareSetPtrVal(ITESimplifier& simp) : d_iteSimplifier(simp), d_refCount(1) {}
};
std::vector<CareSetPtrVal*> d_usedSets;
void careSetPtrGC(CareSetPtrVal* val) {
d_usedSets.push_back(val);
}
class CareSetPtr {
CareSetPtrVal* d_val;
CareSetPtr(CareSetPtrVal* val) : d_val(val) {}
public:
CareSetPtr() : d_val(NULL) {}
CareSetPtr(const CareSetPtr& cs) {
d_val = cs.d_val;
if (d_val != NULL) {
++(d_val->d_refCount);
}
}
~CareSetPtr() {
if (d_val != NULL && (--(d_val->d_refCount) == 0)) {
d_val->d_iteSimplifier.careSetPtrGC(d_val);
}
}
CareSetPtr& operator=(const CareSetPtr& cs) {
if (d_val != cs.d_val) {
if (d_val != NULL && (--(d_val->d_refCount) == 0)) {
d_val->d_iteSimplifier.careSetPtrGC(d_val);
}
d_val = cs.d_val;
if (d_val != NULL) {
++(d_val->d_refCount);
}
}
return *this;
}
std::set<Node>& getCareSet() { return d_val->d_careSet; }
static CareSetPtr mkNew(ITESimplifier& simp) {
CareSetPtrVal* val = new CareSetPtrVal(simp);
return CareSetPtr(val);
}
static CareSetPtr recycle(CareSetPtrVal* val) {
Assert(val != NULL && val->d_refCount == 0);
val->d_refCount = 1;
return CareSetPtr(val);
}
};
CareSetPtr getNewSet();
typedef std::map<TNode, CareSetPtr> CareMap;
void updateQueue(CareMap& queue, TNode e, CareSetPtr& careSet);
Node substitute(TNode e, TNodeMap& substTable, TNodeMap& cache);
public:
Node simplifyWithCare(TNode e);
ITESimplifier() {
d_true = NodeManager::currentNM()->mkConst<bool>(true);
d_false = NodeManager::currentNM()->mkConst<bool>(false);
}
~ITESimplifier() {}
};
}
#endif
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