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/********************* */
/*! \file theory_bv.cpp
** \verbatim
** Original author: dejan
** Major contributors: none
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010 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 [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#include "theory_bv.h"
#include "theory_bv_utils.h"
#include "theory_bv_rewrite_rules.h"
using namespace CVC4;
using namespace CVC4::theory;
using namespace CVC4::theory::bv;
using namespace CVC4::theory::bv::utils;
void TheoryBV::preRegisterTerm(TNode node) {
Debug("bitvector") << "TheoryBV::preRegister(" << node << ")" << std::endl;
if (node.getKind() == kind::EQUAL) {
d_eqEngine.addTerm(node[0]);
d_eqEngine.addTerm(node[1]);
size_t triggerId = d_eqEngine.addTrigger(node[0], node[1]);
Assert(triggerId == d_triggers.size());
d_triggers.push_back(node);
}
}
RewriteResponse TheoryBV::postRewrite(TNode node, bool topLevel) {
Debug("bitvector") << "TheoryBV::postRewrite(" << node << ", topLevel = " << (topLevel? "true" : "false") << ")" << std::endl;
Node result;
if (node.getKind() == kind::CONST_BITVECTOR /* || isLeaf(n)) */)
result = node;
else {
switch (node.getKind()) {
case kind::BITVECTOR_CONCAT:
result = LinearRewriteStrategy<
// Flatten the top level concatenations
CoreRewriteRules::ConcatFlatten,
// Merge the adjacent extracts on non-constants
CoreRewriteRules::ConcatExtractMerge,
// Merge the adjacent extracts on constants
CoreRewriteRules::ConcatConstantMerge,
// At this point only Extract-Whole could apply, if the result is only one extract
// or at some sub-expression if the result is a concatenation.
ApplyRuleToChildren<kind::BITVECTOR_CONCAT, CoreRewriteRules::ExtractWhole>
>::apply(node);
break;
case kind::BITVECTOR_EXTRACT:
result = LinearRewriteStrategy<
// Extract over a constant gives a constant
CoreRewriteRules::ExtractConstant,
// Extract over an extract is simplified to one extract
CoreRewriteRules::ExtractExtract,
// Extract over a concatenation is distributed to the appropriate concatenations
CoreRewriteRules::ExtractConcat,
// At this point only Extract-Whole could apply
CoreRewriteRules::ExtractWhole
>::apply(node);
break;
case kind::EQUAL:
result = LinearRewriteStrategy<
// Two distinct values rewrite to false
CoreRewriteRules::FailEq,
// If both sides are equal equality is true
CoreRewriteRules::SimplifyEq
>::apply(node);
break;
default:
// TODO: figure out when this is an operator
result = node;
break;
// Unhandled();
}
}
Debug("bitvector") << "TheoryBV::postRewrite(" << node << ", topLevel = " << (topLevel? "true" : "false") << ") => " << result << std::endl;
return RewriteComplete(result);
}
void TheoryBV::check(Effort e) {
Debug("bitvector") << "TheoryBV::check(" << e << ")" << std::endl;
while(!done()) {
// Get the assertion
TNode assertion = get();
d_assertions.insert(assertion);
Debug("bitvector") << "TheoryBV::check(" << e << "): asserting: " << assertion << std::endl;
// Do the right stuff
switch (assertion.getKind()) {
case kind::EQUAL: {
bool ok = d_eqEngine.addEquality(assertion[0], assertion[1]);
if (!ok) return;
break;
}
case kind::NOT: {
// We need to check this as the equality trigger might have been true when we made it
TNode equality = assertion[0];
if (d_eqEngine.areEqual(equality[0], equality[1])) {
vector<TNode> assertions;
d_eqEngine.getExplanation(equality[0], equality[1], assertions);
assertions.push_back(assertion);
d_out->conflict(mkAnd(assertions));
return;
}
break;
}
default:
Unhandled();
}
}
}
bool TheoryBV::triggerEquality(size_t triggerId) {
Debug("bitvector") << "TheoryBV::triggerEquality(" << triggerId << ")" << std::endl;
Assert(triggerId < d_triggers.size());
Debug("bitvector") << "TheoryBV::triggerEquality(" << triggerId << "): " << d_triggers[triggerId] << std::endl;
TNode equality = d_triggers[triggerId];
// If we have just asserted this equality ignore it
if (d_assertions.contains(equality)) return true;
// If we have a negation asserted, we have a confict
if (d_assertions.contains(equality.notNode())) {
vector<TNode> assertions;
d_eqEngine.getExplanation(equality[0], equality[1], assertions);
assertions.push_back(equality.notNode());
d_out->conflict(mkAnd(assertions));
return false;
}
// Otherwise we propagate this equality
d_out->propagate(equality);
return true;
}
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