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/****************************************************************************** |
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* Top contributors (to current version): |
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* Andrew Reynolds, Liana Hadarean, Aina Niemetz |
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* |
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* This file is part of the cvc5 project. |
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* |
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* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS |
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* in the top-level source directory and their institutional affiliations. |
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* All rights reserved. See the file COPYING in the top-level source |
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* directory for licensing information. |
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* **************************************************************************** |
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* |
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* Algebraic solver. |
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*/ |
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#include "theory/bv/bv_subtheory_core.h" |
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#include "expr/skolem_manager.h" |
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#include "options/bv_options.h" |
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#include "options/smt_options.h" |
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#include "smt/smt_statistics_registry.h" |
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#include "theory/bv/bv_solver_layered.h" |
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#include "theory/bv/theory_bv_utils.h" |
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#include "theory/ext_theory.h" |
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#include "theory/theory_model.h" |
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#include "util/rational.h" |
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using namespace std; |
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using namespace cvc5; |
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using namespace cvc5::context; |
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using namespace cvc5::theory; |
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using namespace cvc5::theory::bv; |
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using namespace cvc5::theory::bv::utils; |
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|
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CoreSolver::CoreSolver(context::Context* c, BVSolverLayered* bv) |
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: SubtheorySolver(c, bv), |
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d_notify(*this), |
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d_isComplete(c, true), |
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d_lemmaThreshold(16), |
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d_preregisterCalled(false), |
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d_checkCalled(false), |
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d_bv(bv), |
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d_reasons(c) |
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{ |
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} |
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CoreSolver::~CoreSolver() {} |
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|
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bool CoreSolver::needsEqualityEngine(EeSetupInfo& esi) |
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{ |
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esi.d_notify = &d_notify; |
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esi.d_name = "theory::bv::ee"; |
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return true; |
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} |
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|
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void CoreSolver::finishInit() |
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{ |
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// use the parent's equality engine, which may be the one we allocated above |
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d_equalityEngine = d_bv->d_bv.getEqualityEngine(); |
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|
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// The kinds we are treating as function application in congruence |
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d_equalityEngine->addFunctionKind(kind::BITVECTOR_CONCAT, true); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_AND); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_OR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_XOR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_NOT); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_NAND); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_NOR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_XNOR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_COMP); |
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d_equalityEngine->addFunctionKind(kind::BITVECTOR_MULT, true); |
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d_equalityEngine->addFunctionKind(kind::BITVECTOR_ADD, true); |
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d_equalityEngine->addFunctionKind(kind::BITVECTOR_EXTRACT, true); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SUB); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_NEG); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_UDIV); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_UREM); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SDIV); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SREM); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SMOD); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SHL); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_LSHR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_ASHR); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_ULT); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_ULE); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_UGT); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_UGE); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SLT); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SLE); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SGT); |
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// d_equalityEngine->addFunctionKind(kind::BITVECTOR_SGE); |
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d_equalityEngine->addFunctionKind(kind::BITVECTOR_TO_NAT); |
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d_equalityEngine->addFunctionKind(kind::INT_TO_BITVECTOR); |
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} |
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void CoreSolver::preRegister(TNode node) { |
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d_preregisterCalled = true; |
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if (node.getKind() == kind::EQUAL) { |
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d_equalityEngine->addTriggerPredicate(node); |
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} else { |
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d_equalityEngine->addTerm(node); |
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} |
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} |
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void CoreSolver::explain(TNode literal, std::vector<TNode>& assumptions) { |
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bool polarity = literal.getKind() != kind::NOT; |
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TNode atom = polarity ? literal : literal[0]; |
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if (atom.getKind() == kind::EQUAL) { |
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d_equalityEngine->explainEquality(atom[0], atom[1], polarity, assumptions); |
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} else { |
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d_equalityEngine->explainPredicate(atom, polarity, assumptions); |
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} |
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} |
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bool CoreSolver::check(Theory::Effort e) { |
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Trace("bitvector::core") << "CoreSolver::check \n"; |
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d_bv->d_im.spendResource(Resource::TheoryCheckStep); |
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d_checkCalled = true; |
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Assert(!d_bv->inConflict()); |
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++(d_statistics.d_numCallstoCheck); |
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bool ok = true; |
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std::vector<Node> core_eqs; |
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TNodeBoolMap seen; |
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while (! done()) { |
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TNode fact = get(); |
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if (d_isComplete && !isCompleteForTerm(fact, seen)) { |
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d_isComplete = false; |
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} |
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// only reason about equalities |
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if (fact.getKind() == kind::EQUAL || (fact.getKind() == kind::NOT && fact[0].getKind() == kind::EQUAL)) { |
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ok = assertFactToEqualityEngine(fact, fact); |
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} else { |
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ok = assertFactToEqualityEngine(fact, fact); |
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} |
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if (!ok) |
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return false; |
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} |
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if (Theory::fullEffort(e) && isComplete()) { |
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buildModel(); |
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} |
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return true; |
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} |
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void CoreSolver::buildModel() |
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{ |
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Debug("bv-core") << "CoreSolver::buildModel() \n"; |
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NodeManager* nm = NodeManager::currentNM(); |
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d_modelValues.clear(); |
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TNodeSet constants; |
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TNodeSet constants_in_eq_engine; |
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// collect constants in equality engine |
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eq::EqClassesIterator eqcs_i = eq::EqClassesIterator(d_equalityEngine); |
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while (!eqcs_i.isFinished()) |
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{ |
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TNode repr = *eqcs_i; |
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if (repr.getKind() == kind::CONST_BITVECTOR) |
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{ |
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// must check if it's just the constant |
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eq::EqClassIterator it(repr, d_equalityEngine); |
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if (!(++it).isFinished() || true) |
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{ |
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constants.insert(repr); |
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constants_in_eq_engine.insert(repr); |
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} |
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} |
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++eqcs_i; |
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} |
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// build repr to value map |
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eqcs_i = eq::EqClassesIterator(d_equalityEngine); |
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while (!eqcs_i.isFinished()) |
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{ |
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TNode repr = *eqcs_i; |
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++eqcs_i; |
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if (!repr.isVar() && repr.getKind() != kind::CONST_BITVECTOR |
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&& !d_bv->isSharedTerm(repr)) |
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{ |
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continue; |
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} |
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TypeNode type = repr.getType(); |
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if (type.isBitVector() && repr.getKind() != kind::CONST_BITVECTOR) |
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{ |
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Debug("bv-core-model") << " processing " << repr << "\n"; |
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// we need to assign a value for it |
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TypeEnumerator te(type); |
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Node val; |
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do |
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{ |
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val = *te; |
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++te; |
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// Debug("bv-core-model") << " trying value " << val << "\n"; |
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// Debug("bv-core-model") << " is in set? " << constants.count(val) << |
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// "\n"; Debug("bv-core-model") << " enumerator done? " << |
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// te.isFinished() << "\n"; |
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} while (constants.count(val) != 0 && !(te.isFinished())); |
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if (te.isFinished() && constants.count(val) != 0) |
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{ |
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// if we cannot enumerate anymore values we just return the lemma |
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// stating that at least two of the representatives are equal. |
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std::vector<TNode> representatives; |
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representatives.push_back(repr); |
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for (TNodeSet::const_iterator it = constants_in_eq_engine.begin(); |
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it != constants_in_eq_engine.end(); |
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++it) |
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{ |
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TNode constant = *it; |
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if (utils::getSize(constant) == utils::getSize(repr)) |
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{ |
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representatives.push_back(constant); |
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} |
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} |
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for (ModelValue::const_iterator it = d_modelValues.begin(); |
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it != d_modelValues.end(); |
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++it) |
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{ |
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representatives.push_back(it->first); |
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} |
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std::vector<Node> equalities; |
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for (unsigned i = 0; i < representatives.size(); ++i) |
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{ |
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for (unsigned j = i + 1; j < representatives.size(); ++j) |
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{ |
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TNode a = representatives[i]; |
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TNode b = representatives[j]; |
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if (a.getKind() == kind::CONST_BITVECTOR |
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&& b.getKind() == kind::CONST_BITVECTOR) |
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{ |
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Assert(a != b); |
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continue; |
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} |
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if (utils::getSize(a) == utils::getSize(b)) |
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{ |
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equalities.push_back(nm->mkNode(kind::EQUAL, a, b)); |
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} |
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} |
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} |
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// better off letting the SAT solver split on values |
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if (equalities.size() > d_lemmaThreshold) |
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{ |
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d_isComplete = false; |
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return; |
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} |
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if (equalities.size() == 0) |
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{ |
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Debug("bv-core") << " lemma: true (no equalities)" << std::endl; |
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} |
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else |
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{ |
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Node lemma = utils::mkOr(equalities); |
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d_bv->lemma(lemma); |
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Debug("bv-core") << " lemma: " << lemma << std::endl; |
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} |
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return; |
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} |
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Debug("bv-core-model") << " " << repr << " => " << val << "\n"; |
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constants.insert(val); |
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d_modelValues[repr] = val; |
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} |
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} |
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} |
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bool CoreSolver::assertFactToEqualityEngine(TNode fact, TNode reason) { |
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// Notify the equality engine |
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if (!d_bv->inConflict() |
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&& (!d_bv->wasPropagatedBySubtheory(fact) |
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|| d_bv->getPropagatingSubtheory(fact) != SUB_CORE)) |
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{ |
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Debug("bv-slicer-eq") << "CoreSolver::assertFactToEqualityEngine fact=" << fact << endl; |
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// Debug("bv-slicer-eq") << " reason=" << reason << endl; |
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bool negated = fact.getKind() == kind::NOT; |
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TNode predicate = negated ? fact[0] : fact; |
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if (predicate.getKind() == kind::EQUAL) { |
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if (negated) { |
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// dis-equality |
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d_equalityEngine->assertEquality(predicate, false, reason); |
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} else { |
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// equality |
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d_equalityEngine->assertEquality(predicate, true, reason); |
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} |
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} else { |
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// Adding predicate if the congruence over it is turned on |
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if (d_equalityEngine->isFunctionKind(predicate.getKind())) |
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{ |
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d_equalityEngine->assertPredicate(predicate, !negated, reason); |
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} |
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} |
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} |
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|
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// checking for a conflict |
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if (d_bv->inConflict()) |
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{ |
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return false; |
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} |
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return true; |
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} |
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bool CoreSolver::NotifyClass::eqNotifyTriggerPredicate(TNode predicate, bool value) { |
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Debug("bitvector::core") << "NotifyClass::eqNotifyTriggerPredicate(" << predicate << ", " << (value ? "true" : "false" ) << ")" << std::endl; |
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if (value) { |
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return d_solver.storePropagation(predicate); |
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} |
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return d_solver.storePropagation(predicate.notNode()); |
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} |
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bool CoreSolver::NotifyClass::eqNotifyTriggerTermEquality(TheoryId tag, TNode t1, TNode t2, bool value) { |
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Debug("bitvector::core") << "NotifyClass::eqNotifyTriggerTermMerge(" << t1 << ", " << t2 << ")" << std::endl; |
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if (value) { |
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return d_solver.storePropagation(t1.eqNode(t2)); |
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} else { |
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return d_solver.storePropagation(t1.eqNode(t2).notNode()); |
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} |
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} |
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void CoreSolver::NotifyClass::eqNotifyConstantTermMerge(TNode t1, TNode t2) { |
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d_solver.conflict(t1, t2); |
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} |
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bool CoreSolver::storePropagation(TNode literal) { |
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return d_bv->storePropagation(literal, SUB_CORE); |
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} |
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void CoreSolver::conflict(TNode a, TNode b) { |
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std::vector<TNode> assumptions; |
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d_equalityEngine->explainEquality(a, b, true, assumptions); |
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Node conflict = flattenAnd(assumptions); |
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d_bv->setConflict(conflict); |
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} |
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bool CoreSolver::isCompleteForTerm(TNode term, TNodeBoolMap& seen) { |
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return utils::isEqualityTerm(term, seen); |
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} |
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bool CoreSolver::collectModelValues(TheoryModel* m, |
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const std::set<Node>& termSet) |
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{ |
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if (Debug.isOn("bitvector-model")) { |
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context::CDQueue<Node>::const_iterator it = d_assertionQueue.begin(); |
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for (; it!= d_assertionQueue.end(); ++it) { |
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Debug("bitvector-model") |
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<< "CoreSolver::collectModelValues (assert " << *it << ")\n"; |
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} |
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} |
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if (isComplete()) { |
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Debug("bitvector-model") << "CoreSolver::collectModelValues complete."; |
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for (ModelValue::const_iterator it = d_modelValues.begin(); it != d_modelValues.end(); ++it) { |
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Node a = it->first; |
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Node b = it->second; |
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Debug("bitvector-model") << "CoreSolver::collectModelValues modelValues " |
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<< a << " => " << b << ")\n"; |
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if (!m->assertEquality(a, b, true)) |
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{ |
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return false; |
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} |
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} |
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} |
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return true; |
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} |
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Node CoreSolver::getModelValue(TNode var) { |
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Debug("bitvector-model") << "CoreSolver::getModelValue (" << var <<")"; |
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Assert(isComplete()); |
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TNode repr = d_equalityEngine->getRepresentative(var); |
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Node result = Node(); |
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if (repr.getKind() == kind::CONST_BITVECTOR) { |
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result = repr; |
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} else if (d_modelValues.find(repr) == d_modelValues.end()) { |
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// it may be a shared term that never gets asserted |
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// result is just Null |
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Assert(d_bv->isSharedTerm(var)); |
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} else { |
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result = d_modelValues[repr]; |
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} |
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Debug("bitvector-model") << " => " << result <<"\n"; |
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return result; |
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} |
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|
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EqualityStatus CoreSolver::getEqualityStatus(TNode a, TNode b) |
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{ |
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if (d_equalityEngine->areEqual(a, b)) |
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{ |
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// The terms are implied to be equal |
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return EQUALITY_TRUE; |
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} |
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if (d_equalityEngine->areDisequal(a, b, false)) |
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{ |
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// The terms are implied to be dis-equal |
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return EQUALITY_FALSE; |
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} |
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return EQUALITY_UNKNOWN; |
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} |
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|
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bool CoreSolver::hasTerm(TNode node) const |
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{ |
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return d_equalityEngine->hasTerm(node); |
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} |
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void CoreSolver::addTermToEqualityEngine(TNode node) |
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{ |
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d_equalityEngine->addTerm(node); |
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} |
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|
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CoreSolver::Statistics::Statistics() |
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: d_numCallstoCheck(smtStatisticsRegistry().registerInt( |
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"theory::bv::CoreSolver::NumCallsToCheck")) |
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{ |
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29505 |
} |