This changes the lemma vs fact policy for datatype equalities. Previously, datatype equalities were sent as lemmas unless they were over datatypes that were composed of datatypes only. This is now changed so that equalities that do not involve direct subterms with finite non-datatype types are kept internal.
The primary type of equality that this targets are "Instantiate" equalities, e.g. the conclusion of:
(is-cons x) => x = (cons (head x) (tail x))
These equalities have been observed to generate large amounts of new terms for many benchmarks.
With this PR, the the challenging Facebook benchmark goes from 2 min 45 sec -> 29 sec. If the instantiate rule is disabled altogether, it still correctly solves, and is faster (~14 seconds), which however is not correct in general.
This change triggered two other issues:
(1) A relations benchmark involving transitive closure now times out. This has been a common issue for the relations solver and should be revisited.
(2) A potential issue with doPendingLemmas in InferenceManagerBuffer was uncovered. In rare cases, we can be re-entrant into this method since OutputChannel::lemma may trigger further preregistration of terms, which can trigger a recursive call to doPendingLemmas in the case of datatypes, which causes a segfault due to corrupting an iterator. This PR adds a simple guard for this method.
This PR also fixes some existing issues in computing cardinality for parametric datatypes.
bool DTypeConstructor::isFinite(TypeNode t) const
{
- Assert(isResolved());
-
- TNode self = d_constructor;
- // is this already in the cache ?
- if (self.getAttribute(DTypeFiniteComputedAttr()))
- {
- return self.getAttribute(DTypeFiniteAttr());
- }
- std::vector<TypeNode> instTypes;
- std::vector<TypeNode> paramTypes;
- bool isParam = t.isParametricDatatype();
- if (isParam)
- {
- paramTypes = t.getDType().getParameters();
- instTypes = TypeNode(t).getParamTypes();
- }
- for (size_t i = 0, nargs = getNumArgs(); i < nargs; i++)
- {
- TypeNode tc = getArgType(i);
- if (isParam)
- {
- tc = tc.substitute(paramTypes.begin(),
- paramTypes.end(),
- instTypes.begin(),
- instTypes.end());
- }
- if (!tc.isFinite())
- {
- self.setAttribute(DTypeFiniteComputedAttr(), true);
- self.setAttribute(DTypeFiniteAttr(), false);
- return false;
- }
- }
- self.setAttribute(DTypeFiniteComputedAttr(), true);
- self.setAttribute(DTypeFiniteAttr(), true);
- return true;
+ std::pair<CardinalityType, bool> cinfo = computeCardinalityInfo(t);
+ return cinfo.first == CardinalityType::FINITE;
}
bool DTypeConstructor::isInterpretedFinite(TypeNode t) const
{
- Assert(isResolved());
- TNode self = d_constructor;
- // is this already in the cache ?
- if (self.getAttribute(DTypeUFiniteComputedAttr()))
+ std::pair<CardinalityType, bool> cinfo = computeCardinalityInfo(t);
+ return cinfo.first != CardinalityType::INFINITE;
+}
+
+bool DTypeConstructor::hasFiniteExternalArgType(TypeNode t) const
+{
+ std::pair<CardinalityType, bool> cinfo = computeCardinalityInfo(t);
+ return cinfo.second;
+}
+
+std::pair<DTypeConstructor::CardinalityType, bool>
+DTypeConstructor::computeCardinalityInfo(TypeNode t) const
+{
+ std::map<TypeNode, std::pair<CardinalityType, bool> >::iterator it =
+ d_cardInfo.find(t);
+ if (it != d_cardInfo.end())
{
- return self.getAttribute(DTypeUFiniteAttr());
+ return it->second;
}
+ std::pair<CardinalityType, bool> ret(CardinalityType::FINITE, false);
std::vector<TypeNode> instTypes;
std::vector<TypeNode> paramTypes;
bool isParam = t.isParametricDatatype();
if (isParam)
{
paramTypes = t.getDType().getParameters();
- instTypes = TypeNode(t).getParamTypes();
+ instTypes = t.getParamTypes();
}
for (unsigned i = 0, nargs = getNumArgs(); i < nargs; i++)
{
instTypes.begin(),
instTypes.end());
}
- if (!tc.isInterpretedFinite())
+ if (tc.isFinite())
+ {
+ // do nothing
+ }
+ else if (tc.isInterpretedFinite())
+ {
+ if (ret.first == CardinalityType::FINITE)
+ {
+ // not simply finite, it depends on uninterpreted sorts being finite
+ ret.first = CardinalityType::INTERPRETED_FINITE;
+ }
+ }
+ else
{
- self.setAttribute(DTypeUFiniteComputedAttr(), true);
- self.setAttribute(DTypeUFiniteAttr(), false);
- return false;
+ // infinite implies the constructor is infinite cardinality
+ ret.first = CardinalityType::INFINITE;
+ continue;
}
+ // if the argument is (interpreted) finite and external, set the flag
+ // for indicating it has a finite external argument
+ ret.second = ret.second || !tc.isDatatype();
}
- self.setAttribute(DTypeUFiniteComputedAttr(), true);
- self.setAttribute(DTypeUFiniteAttr(), true);
- return true;
+ d_cardInfo[t] = ret;
+ return ret;
}
bool DTypeConstructor::isResolved() const { return !d_tester.isNull(); }
* only be called for resolved constructors.
*/
bool isInterpretedFinite(TypeNode t) const;
+ /**
+ * Has finite external argument type. This returns true if this constructor
+ * has an argument type that is not a datatype and is interpreted as a
+ * finite type. This function can only be called for resolved constructors.
+ *
+ */
+ bool hasFiniteExternalArgType(TypeNode t) const;
/**
* Returns true iff this constructor has already been
void toStream(std::ostream& out) const;
private:
+ /** Constructor cardinality type */
+ enum class CardinalityType
+ {
+ // the constructor is finite
+ FINITE,
+ // the constructor is interpreted-finite (finite under the assumption that
+ // uninterpreted sorts are finite)
+ INTERPRETED_FINITE,
+ // the constructor is infinte
+ INFINITE
+ };
/** resolve
*
* This resolves (initializes) the constructor. For details
std::vector<TypeNode>& processing,
std::map<TypeNode, Node>& gt,
bool isValue) const;
+ /**
+ * Compute cardinality info, returns a pair where its first component is
+ * an identifier indicating the cardinality type of this constructor for
+ * type t, and a Boolean indicating whether the constructor has any arguments
+ * that have finite external type.
+ */
+ std::pair<CardinalityType, bool> computeCardinalityInfo(TypeNode t) const;
/** compute shared selectors
* This computes the maps d_sharedSelectors and d_sharedSelectorIndex.
*/
* its argument index for this constructor.
*/
mutable std::map<TypeNode, std::map<Node, unsigned> > d_sharedSelectorIndex;
+ /** A cache for computeCardinalityInfo. */
+ mutable std::map<TypeNode, std::pair<CardinalityType, bool> > d_cardInfo;
}; /* class DTypeConstructor */
/**
}
else if (n.getKind() == EQUAL)
{
+ // Note that equalities due to instantiate are forced as lemmas if
+ // necessary as they are created. This ensures that terms are shared with
+ // external theories when necessary. We send the lemma here only if
+ // the equality is not for datatype terms, which can happen for collapse
+ // selector / term size or unification.
TypeNode tn = n[0].getType();
- if (!tn.isDatatype())
- {
- addLemma = true;
- }
- else
- {
- const DType& dt = tn.getDType();
- addLemma = dt.involvesExternalType();
- }
+ addLemma = !tn.isDatatype();
}
else if (n.getKind() == LEQ || n.getKind() == OR)
{
bool DatatypesInference::process(TheoryInferenceManager* im, bool asLemma)
{
- // check to see if we have to communicate it to the rest of the system
- if (mustCommunicateFact(d_conc, d_exp))
+ // Check to see if we have to communicate it to the rest of the system.
+ // The flag asLemma is true when the inference was marked that it must be
+ // sent as a lemma in addPendingInference below.
+ if (asLemma || mustCommunicateFact(d_conc, d_exp))
{
// send it as an (explained) lemma
std::vector<Node> exp;
void InferenceManager::addPendingInference(Node conc,
Node exp,
- ProofGenerator* pg)
+ ProofGenerator* pg,
+ bool forceLemma)
{
- d_pendingFact.emplace_back(new DatatypesInference(conc, exp, pg));
+ if (forceLemma)
+ {
+ d_pendingLem.emplace_back(new DatatypesInference(conc, exp, pg));
+ }
+ else
+ {
+ d_pendingFact.emplace_back(new DatatypesInference(conc, exp, pg));
+ }
}
void InferenceManager::process()
/**
* Add pending inference, which may be processed as either a fact or
* a lemma based on mustCommunicateFact in DatatypesInference above.
+ *
+ * @param conc The conclusion of the inference
+ * @param exp The explanation of the inference
+ * @param pg The proof generator who can provide a proof of (conc => exp)
+ * @param forceLemma Whether this inference *must* be processed as a lemma.
+ * Otherwise, it may be processed as a fact or lemma based on
+ * mustCommunicateFact.
*/
- void addPendingInference(Node conc, Node exp, ProofGenerator* pg = nullptr);
+ void addPendingInference(Node conc,
+ Node exp,
+ ProofGenerator* pg = nullptr,
+ bool forceLemma = false);
/**
* Process the current lemmas and facts. This is a custom method that can
* be seen as overriding the behavior of calling both doPendingLemmas and
exp = getLabel(n);
tt = exp[0];
}
- const DType& dt = tt.getType().getDType();
+ TypeNode ttn = tt.getType();
+ const DType& dt = ttn.getDType();
// instantiate this equivalence class
eqc->d_inst = true;
Node tt_cons = getInstantiateCons(tt, dt, index);
return;
}
eq = tt.eqNode(tt_cons);
- Debug("datatypes-inst") << "DtInstantiate : " << eqc << " " << eq
- << std::endl;
- d_im.addPendingInference(eq, exp);
- Trace("datatypes-infer-debug") << "inst : " << eqc << " " << n << std::endl;
+ // Determine if the equality must be sent out as a lemma. Notice that
+ // we can keep new equalities from the instantiate rule internal as long as
+ // they are for datatype constructors that have no arguments that have
+ // finite external type. Such equalities must be sent because they introduce
+ // selector terms that may contribute to conflicts due to cardinality (good
+ // examples of this are regress0/datatypes/dt-param-card4-bool-sat.smt2 and
+ // regress0/datatypes/list-bool.smt2).
+ bool forceLemma = dt[index].hasFiniteExternalArgType(ttn);
+ Trace("datatypes-infer-debug") << "DtInstantiate : " << eqc << " " << eq
+ << " forceLemma = " << forceLemma << std::endl;
+ d_im.addPendingInference(eq, exp, nullptr, forceLemma);
Trace("datatypes-infer") << "DtInfer : instantiate : " << eq << " by " << exp
<< std::endl;
}
InferenceManagerBuffered::InferenceManagerBuffered(Theory& t,
TheoryState& state,
ProofNodeManager* pnm)
- : TheoryInferenceManager(t, state, pnm)
+ : TheoryInferenceManager(t, state, pnm), d_processingPendingLemmas(false)
{
}
void InferenceManagerBuffered::doPendingLemmas()
{
+ if (d_processingPendingLemmas)
+ {
+ // already processing
+ return;
+ }
+ d_processingPendingLemmas = true;
for (const std::unique_ptr<TheoryInference>& plem : d_pendingLem)
{
// process this lemma
plem->process(this, true);
}
d_pendingLem.clear();
+ d_processingPendingLemmas = false;
}
void InferenceManagerBuffered::doPendingPhaseRequirements()
std::vector<std::unique_ptr<TheoryInference>> d_pendingFact;
/** A map from literals to their pending phase requirement */
std::map<Node, bool> d_pendingReqPhase;
+ /**
+ * Whether we are currently processing pending lemmas. This flag ensures
+ * that we do not call pending lemmas recursively, which may lead to
+ * segfaults.
+ */
+ bool d_processingPendingLemmas;
};
} // namespace theory
regress0/datatypes/datatype3.cvc
regress0/datatypes/datatype4.cvc
regress0/datatypes/dt-2.6.smt2
+ regress0/datatypes/dt-different-params.smt2
regress0/datatypes/dt-match-pat-param-2.6.smt2
regress0/datatypes/dt-param-2.6.smt2
regress0/datatypes/dt-param-2.6-print.smt2
regress0/datatypes/issue1433.smt2
regress0/datatypes/issue2838.cvc
regress0/datatypes/jsat-2.6.smt2
+ regress0/datatypes/list-bool.smt2
regress0/datatypes/model-subterms-min.smt2
regress0/datatypes/mutually-recursive.cvc
regress0/datatypes/pair-bool-bool.cvc
regress1/rels/rel_pressure_0.cvc
regress1/rels/rel_tc_10_1.cvc
regress1/rels/rel_tc_4.cvc
- regress1/rels/rel_tc_4_1.cvc
regress1/rels/rel_tc_5_1.cvc
regress1/rels/rel_tc_6.cvc
regress1/rels/rel_tc_9_1.cvc
# doing a coverage build with LFSC.
regress1/quantifiers/set3.smt2
regress1/rels/garbage_collect.cvc
+ # times out after dt fact update due to overly eager splitting for tclosure
+ regress1/rels/rel_tc_4_1.cvc
regress1/sets/setofsets-disequal.smt2
regress1/sets/finite-type/sets-card-neg-mem-union-2.smt2
regress1/simple-rdl-definefun.smt2
--- /dev/null
+(set-logic QF_ALL_SUPPORTED)
+(set-info :status unsat)
+(declare-datatypes ((Data 1)) ((par (T) ((data (first T))))))
+
+(declare-fun q1 () (Data Int))
+(declare-fun q2 () (Data Int))
+(declare-fun q3 () (Data Int))
+
+(assert (distinct q1 q2 q3))
+
+(declare-fun p1 () (Data Bool))
+(declare-fun p2 () (Data Bool))
+(declare-fun p3 () (Data Bool))
+
+(assert (distinct p1 p2 p3))
+(check-sat)
--- /dev/null
+(set-logic ALL)
+(set-info :status unsat)
+(declare-datatypes ((list 0)) (
+((cons (head Bool) (tail list)) (nil))
+))
+(declare-fun x1 () list)
+(declare-fun x2 () list)
+(declare-fun x3 () list)
+(assert (= (tail x1) nil))
+(assert (= (tail x2) nil))
+(assert (= (tail x3) nil))
+(assert (distinct x1 x2 x3 nil))
+(check-sat)
projects / cvc5.git / commitdiff