void SygusRedundantCons::initialize(QuantifiersEngine* qe, TypeNode tn)
{
Assert(qe != nullptr);
Trace("sygus-red") << "Compute redundant cons for " << tn << std::endl;
d_type = tn;
Assert(tn.isDatatype());
TermDbSygus* tds = qe->getTermDatabaseSygus();
tds->registerSygusType(tn);
const Datatype& dt = static_cast<DatatypeType>(tn.toType()).getDatatype();
Assert(dt.isSygus());
TypeNode btn = TypeNode::fromType(dt.getSygusType());
for (unsigned i = 0, ncons = dt.getNumConstructors(); i < ncons; i++)
{
Trace("sygus-red") << " Is " << dt[i].getName() << " a redundant operator?"
<< std::endl;
std::map<int, Node> pre;
Node g = tds->mkGeneric(dt, i, pre);
Trace("sygus-red-debug") << " ...pre-rewrite : " << g << std::endl;
Assert(g.getNumChildren() == dt[i].getNumArgs());
d_gen_terms[i] = g;
for (unsigned j = 0, nargs = dt[i].getNumArgs(); j < nargs; j++)
{
pre[j] = g[j];
}
std::vector<Node> glist;
getGenericList(tds, dt, i, 0, pre, glist);
// call the extended rewriter
bool red = false;
for (const Node& gr : glist)
{
Trace("sygus-red-debug") << " ...variant : " << gr << std::endl;
std::map<Node, unsigned>::iterator itg = d_gen_cons.find(gr);
if (itg != d_gen_cons.end() && itg->second != i)
{
red = true;
Trace("sygus-red") << " ......redundant, since a variant of " << g
<< " and " << d_gen_terms[itg->second]
<< " both rewrite to " << gr << std::endl;
break;
}
else
{
d_gen_cons[gr] = i;
Trace("sygus-red") << " ......not redundant." << std::endl;
}
}
d_sygus_red_status.push_back(red ? 1 : 0);
}
}
Node DtInstantiator::solve_dt(Node v, Node a, Node b, Node sa, Node sb)
{
Trace("cegqi-arith-debug2") << "Solve dt : " << v << " " << a << " " << b
<< " " << sa << " " << sb << std::endl;
Node ret;
if (!a.isNull() && a == v)
{
ret = sb;
}
else if (!b.isNull() && b == v)
{
ret = sa;
}
else if (!a.isNull() && a.getKind() == APPLY_CONSTRUCTOR)
{
if (!b.isNull() && b.getKind() == APPLY_CONSTRUCTOR)
{
if (a.getOperator() == b.getOperator())
{
for (unsigned i = 0, nchild = a.getNumChildren(); i < nchild; i++)
{
Node s = solve_dt(v, a[i], b[i], sa[i], sb[i]);
if (!s.isNull())
{
return s;
}
}
}
}
else
{
NodeManager* nm = NodeManager::currentNM();
unsigned cindex = Datatype::indexOf(a.getOperator().toExpr());
TypeNode tn = a.getType();
const Datatype& dt = static_cast<DatatypeType>(tn.toType()).getDatatype();
for (unsigned i = 0, nchild = a.getNumChildren(); i < nchild; i++)
{
Node nn = nm->mkNode(
APPLY_SELECTOR_TOTAL,
Node::fromExpr(dt[cindex].getSelectorInternal(tn.toType(), i)),
sb);
Node s = solve_dt(v, a[i], Node::null(), sa[i], nn);
if (!s.isNull())
{
return s;
}
}
}
}
else if (!b.isNull() && b.getKind() == APPLY_CONSTRUCTOR)
{
// flip sides
return solve_dt(v, b, a, sb, sa);
}
if (!ret.isNull())
{
// ensure does not contain v
if (expr::hasSubterm(ret, v))
{
ret = Node::null();
}
}
return ret;
}
void UnconstrainedSimplifier::processUnconstrained()
{
TNodeSet::iterator it = d_unconstrained.begin(), iend = d_unconstrained.end();
vector<TNode> workList;
for ( ; it != iend; ++it) {
workList.push_back(*it);
}
Node currentSub;
TNode parent;
bool swap;
bool isSigned;
bool strict;
vector<TNode> delayQueueLeft;
vector<Node> delayQueueRight;
TNode current = workList.back();
workList.pop_back();
for (;;) {
Assert(d_visitedOnce.find(current) != d_visitedOnce.end());
parent = d_visitedOnce[current];
if (!parent.isNull()) {
swap = isSigned = strict = false;
switch (parent.getKind()) {
// If-then-else operator - any two unconstrained children makes the parent unconstrained
case kind::ITE: {
Assert(parent[0] == current || parent[1] == current || parent[2] == current);
bool uCond = parent[0] == current || d_unconstrained.find(parent[0]) != d_unconstrained.end();
bool uThen = parent[1] == current || d_unconstrained.find(parent[1]) != d_unconstrained.end();
bool uElse = parent[2] == current || d_unconstrained.find(parent[2]) != d_unconstrained.end();
if ((uCond && uThen) || (uCond && uElse) || (uThen && uElse)) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (uThen) {
if (parent[1] != current) {
if (parent[1].isVar()) {
currentSub = parent[1];
}
else {
Assert(d_substitutions.hasSubstitution(parent[1]));
currentSub = d_substitutions.apply(parent[1]);
}
}
else if (currentSub.isNull()) {
currentSub = current;
}
}
else if (parent[2] != current) {
if (parent[2].isVar()) {
currentSub = parent[2];
}
else {
Assert(d_substitutions.hasSubstitution(parent[2]));
currentSub = d_substitutions.apply(parent[2]);
}
}
else if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
}
else if (uCond) {
Cardinality card = parent.getType().getCardinality();
if (card.isFinite() && !card.isLargeFinite() && card.getFiniteCardinality() == 2) {
// Special case: condition is unconstrained, then and else are different, and total cardinality of the type is 2, then the result
// is unconstrained
Node test;
if (parent.getType().isBoolean()) {
test = Rewriter::rewrite(parent[1].iffNode(parent[2]));
}
else {
test = Rewriter::rewrite(parent[1].eqNode(parent[2]));
}
if (test == NodeManager::currentNM()->mkConst<bool>(false)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
}
}
}
break;
}
// Comparisons that return a different type - assuming domains are larger than 1, any
// unconstrained child makes parent unconstrained as well
case kind::EQUAL:
if (parent[0].getType() != parent[1].getType()) {
TNode other = (parent[0] == current) ? parent[1] : parent[0];
if (current.getType().isSubtypeOf(other.getType())) {
break;
}
}
if( parent[0].getType().isDatatype() ){
TypeNode tn = parent[0].getType();
const Datatype& dt = ((DatatypeType)(tn).toType()).getDatatype();
if( dt.isRecursiveSingleton( tn.toType() ) ){
//domain size may be 1
break;
}
}
case kind::BITVECTOR_COMP:
case kind::LT:
case kind::LEQ:
case kind::GT:
case kind::GEQ:
{
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
Assert(parent[0] != parent[1] &&
(parent[0] == current || parent[1] == current));
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
}
else {
currentSub = Node();
}
break;
}
// Unary operators that propagate unconstrainedness
case kind::NOT:
case kind::BITVECTOR_NOT:
case kind::BITVECTOR_NEG:
case kind::UMINUS:
++d_numUnconstrainedElim;
Assert(parent[0] == current);
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
break;
// Unary operators that propagate unconstrainedness and return a different type
case kind::BITVECTOR_EXTRACT:
++d_numUnconstrainedElim;
Assert(parent[0] == current);
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
break;
// Operators returning same type requiring all children to be unconstrained
case kind::AND:
case kind::OR:
case kind::IMPLIES:
case kind::BITVECTOR_AND:
case kind::BITVECTOR_OR:
case kind::BITVECTOR_NAND:
case kind::BITVECTOR_NOR:
{
bool allUnconstrained = true;
for(TNode::iterator child_it = parent.begin(); child_it != parent.end(); ++child_it) {
if (d_unconstrained.find(*child_it) == d_unconstrained.end()) {
allUnconstrained = false;
break;
}
}
if (allUnconstrained) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
}
}
break;
// Require all children to be unconstrained and different
case kind::BITVECTOR_SHL:
case kind::BITVECTOR_LSHR:
case kind::BITVECTOR_ASHR:
case kind::BITVECTOR_UDIV_TOTAL:
case kind::BITVECTOR_UREM_TOTAL:
case kind::BITVECTOR_SDIV:
case kind::BITVECTOR_SREM:
case kind::BITVECTOR_SMOD: {
bool allUnconstrained = true;
bool allDifferent = true;
for(TNode::iterator child_it = parent.begin(); child_it != parent.end(); ++child_it) {
if (d_unconstrained.find(*child_it) == d_unconstrained.end()) {
allUnconstrained = false;
break;
}
for(TNode::iterator child_it2 = child_it + 1; child_it2 != parent.end(); ++child_it2) {
if (*child_it == *child_it2) {
allDifferent = false;
break;
}
}
}
if (allUnconstrained && allDifferent) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
}
break;
}
// Requires all children to be unconstrained and different, and returns a different type
case kind::BITVECTOR_CONCAT:
{
bool allUnconstrained = true;
bool allDifferent = true;
for(TNode::iterator child_it = parent.begin(); child_it != parent.end(); ++child_it) {
if (d_unconstrained.find(*child_it) == d_unconstrained.end()) {
allUnconstrained = false;
break;
}
for(TNode::iterator child_it2 = child_it + 1; child_it2 != parent.end(); ++child_it2) {
if (*child_it == *child_it2) {
allDifferent = false;
break;
}
}
}
if (allUnconstrained && allDifferent) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
}
else {
currentSub = Node();
}
}
}
break;
// N-ary operators returning same type requiring at least one child to be unconstrained
case kind::PLUS:
case kind::MINUS:
if (current.getType().isInteger() &&
!parent.getType().isInteger()) {
break;
}
case kind::IFF:
case kind::XOR:
case kind::BITVECTOR_XOR:
case kind::BITVECTOR_XNOR:
case kind::BITVECTOR_PLUS:
case kind::BITVECTOR_SUB:
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
break;
// Multiplication/division: must be non-integer and other operand must be non-zero
case kind::MULT: {
case kind::DIVISION:
Assert(parent.getNumChildren() == 2);
TNode other;
if (parent[0] == current) {
other = parent[1];
}
else {
Assert(parent[1] == current);
other = parent[0];
}
if (d_unconstrained.find(other) != d_unconstrained.end()) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
if (current.getType().isInteger() && other.getType().isInteger()) {
Assert(parent.getKind() == kind::DIVISION || parent.getType().isInteger());
if (parent.getKind() == kind::DIVISION) {
break;
}
}
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
}
else {
// if only the denominator of a division is unconstrained, can't set it to 0 so the result is not unconstrained
if (parent.getKind() == kind::DIVISION && current == parent[1]) {
break;
}
NodeManager* nm = NodeManager::currentNM();
// if we are an integer, the only way we are unconstrained is if we are a MULT by -1
if (current.getType().isInteger()) {
// div/mult by 1 should have been simplified
Assert(other != nm->mkConst<Rational>(1));
if (other == nm->mkConst<Rational>(-1)) {
// div by -1 should have been simplified
Assert(parent.getKind() == kind::MULT);
Assert(parent.getType().isInteger());
}
else {
break;
}
}
else {
// TODO: could build ITE here
Node test = other.eqNode(nm->mkConst<Rational>(0));
if (Rewriter::rewrite(test) != nm->mkConst<bool>(false)) {
break;
}
}
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
break;
}
// Bitvector MULT - current must only appear once in the children:
// all other children must be unconstrained or odd
case kind::BITVECTOR_MULT:
{
bool found = false;
bool done = false;
for(TNode::iterator child_it = parent.begin(); child_it != parent.end(); ++child_it) {
if ((*child_it) == current) {
if (found) {
done = true;
break;
}
found = true;
continue;
}
else if (d_unconstrained.find(*child_it) != d_unconstrained.end()) {
continue;
}
else {
NodeManager* nm = NodeManager::currentNM();
Node extractOp = nm->mkConst<BitVectorExtract>(BitVectorExtract(0,0));
vector<Node> children;
children.push_back(*child_it);
Node test = nm->mkNode(extractOp, children);
BitVector one(1,unsigned(1));
test = test.eqNode(nm->mkConst<BitVector>(one));
if (Rewriter::rewrite(test) != nm->mkConst<bool>(true)) {
done = true;
break;
}
}
}
if (done) {
break;
}
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
break;
}
// Uninterpreted function - if domain is infinite, no quantifiers are used, and any child is unconstrained, result is unconstrained
case kind::APPLY_UF:
if (d_logicInfo.isQuantified() || !current.getType().getCardinality().isInfinite()) {
break;
}
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
if (parent.getType() != current.getType()) {
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
}
current = parent;
}
else {
currentSub = Node();
}
break;
// Array select - if array is unconstrained, so is result
case kind::SELECT:
if (parent[0] == current) {
++d_numUnconstrainedElim;
Assert(current.getType().isArray());
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(current.getType().getArrayConstituentType(), currentSub);
current = parent;
}
break;
// Array store - if both store and value are unconstrained, so is resulting store
case kind::STORE:
if (((parent[0] == current &&
d_unconstrained.find(parent[2]) != d_unconstrained.end()) ||
(parent[2] == current &&
d_unconstrained.find(parent[0]) != d_unconstrained.end()))) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (parent[0] != current) {
if (parent[0].isVar()) {
currentSub = parent[0];
}
else {
Assert(d_substitutions.hasSubstitution(parent[0]));
currentSub = d_substitutions.apply(parent[0]);
}
}
else if (currentSub.isNull()) {
currentSub = current;
}
current = parent;
}
else {
currentSub = Node();
}
}
break;
// Bit-vector comparisons: replace with new Boolean variable, but have
// to also conjoin with a side condition as there is always one case
// when the comparison is forced to be false
case kind::BITVECTOR_ULT:
case kind::BITVECTOR_UGE:
case kind::BITVECTOR_UGT:
case kind::BITVECTOR_ULE:
case kind::BITVECTOR_SLT:
case kind::BITVECTOR_SGE:
case kind::BITVECTOR_SGT:
case kind::BITVECTOR_SLE: {
// Tuples over (signed, swap, strict).
switch (parent.getKind()) {
case kind::BITVECTOR_UGE:
break;
case kind::BITVECTOR_ULT:
strict = true;
break;
case kind::BITVECTOR_ULE:
swap = true;
break;
case kind::BITVECTOR_UGT:
swap = true;
strict = true;
break;
case kind::BITVECTOR_SGE:
isSigned = true;
break;
case kind::BITVECTOR_SLT:
isSigned = true;
strict = true;
break;
case kind::BITVECTOR_SLE:
isSigned = true;
swap = true;
break;
case kind::BITVECTOR_SGT:
isSigned = true;
swap = true;
strict = true;
break;
default:
Unreachable();
}
TNode other;
bool left = false;
if (parent[0] == current) {
other = parent[1];
left = true;
} else {
Assert(parent[1] == current);
other = parent[0];
}
if (d_unconstrained.find(other) != d_unconstrained.end()) {
if (d_unconstrained.find(parent) == d_unconstrained.end() &&
!d_substitutions.hasSubstitution(parent)) {
++d_numUnconstrainedElim;
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
} else {
currentSub = Node();
}
} else {
unsigned size = current.getType().getBitVectorSize();
BitVector bv =
isSigned ? BitVector(size, Integer(1).multiplyByPow2(size - 1))
: BitVector(size, unsigned(0));
if (swap == left) {
bv = ~bv;
}
if (currentSub.isNull()) {
currentSub = current;
}
currentSub = newUnconstrainedVar(parent.getType(), currentSub);
current = parent;
NodeManager* nm = NodeManager::currentNM();
Node test =
Rewriter::rewrite(other.eqNode(nm->mkConst<BitVector>(bv)));
if (test == nm->mkConst<bool>(false)) {
break;
}
if (strict) {
currentSub = currentSub.andNode(test.notNode());
} else {
currentSub = currentSub.orNode(test);
}
// Delay adding this substitution - see comment at end of function
delayQueueLeft.push_back(current);
delayQueueRight.push_back(currentSub);
currentSub = Node();
parent = TNode();
}
break;
}
// Do nothing
case kind::BITVECTOR_SIGN_EXTEND:
case kind::BITVECTOR_ZERO_EXTEND:
case kind::BITVECTOR_REPEAT:
case kind::BITVECTOR_ROTATE_LEFT:
case kind::BITVECTOR_ROTATE_RIGHT:
default:
break;
}
if (current == parent && d_visited[parent] == 1) {
d_unconstrained.insert(parent);
continue;
}
}
if (!currentSub.isNull()) {
Assert(currentSub.isVar());
d_substitutions.addSubstitution(current, currentSub, false);
}
if (workList.empty()) {
break;
}
current = workList.back();
currentSub = Node();
workList.pop_back();
}
TNode left;
Node right;
// All substitutions except those arising from bitvector comparisons are
// substitutions t -> x where x is a variable. This allows us to build the
// substitution very quickly (never invalidating the substitution cache).
// Bitvector comparisons are more complicated and may require
// back-substitution and cache-invalidation. So we do these last.
while (!delayQueueLeft.empty()) {
left = delayQueueLeft.back();
if (!d_substitutions.hasSubstitution(left)) {
right = d_substitutions.apply(delayQueueRight.back());
d_substitutions.addSubstitution(delayQueueLeft.back(), right);
}
delayQueueLeft.pop_back();
delayQueueRight.pop_back();
}
}
