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check that a clause was not removed to fix issue #551

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-04-04 20:15:49 +02:00
parent ec5a4ba63d
commit ed1a5797fb
3 changed files with 30 additions and 11 deletions
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2
src/sat/sat_simplifier.cpp
View file

@ -401,7 +401,7 @@ namespace sat {
literal_vector::iterator l_it = m_bs_ls.begin();
for (; it != end; ++it, ++l_it) {
clause & c2 = *(*it);
if (*l_it == null_literal) {
if (!c2.was_removed() && *l_it == null_literal) {
// c2 was subsumed
if (c1.is_learned() && !c2.is_learned())
c1.unset_learned();

37
src/smt/theory_seq.cpp
View file

@ -15,7 +15,6 @@ Author:
Revision History:
// Use instead reference counts for dependencies to GC?
--*/
@ -258,7 +257,7 @@ final_check_status theory_seq::final_check_eh() {
TRACE("seq", tout << ">>fixed_length\n";);
return FC_CONTINUE;
}
if (reduce_length_eq() || /*branch_variable_mb() || */ branch_variable()) {
if (reduce_length_eq() || branch_variable_mb() || branch_variable()) {
++m_stats.m_branch_variable;
TRACE("seq", tout << ">>branch_variable\n";);
return FC_CONTINUE;
@ -315,11 +314,15 @@ bool theory_seq::branch_variable_mb() {
unsigned k = (i + start) % sz;
eq const& e = m_eqs[i];
vector<rational> len1, len2;
if (!is_complex(e)) {
continue;
}
if (!enforce_length(e.ls(), len1) || !enforce_length(e.rs(), len2)) {
change = true;
continue;
}
if (e.ls().empty() || e.rs().empty() || (!is_var(e.ls()[0]) && !is_var(e.rs()[0]))) {
if (e.ls().empty() || e.rs().empty() ||
(!is_var(e.ls()[0]) && !is_var(e.rs()[0]))) {
continue;
}
rational l1, l2;
@ -335,13 +338,25 @@ bool theory_seq::branch_variable_mb() {
continue;
}
if (split_lengths(e.dep(), e.ls(), e.rs(), len1, len2)) {
TRACE("seq", display_equation(tout, e););
return true;
}
}
return change;
}
bool theory_seq::is_complex(eq const& e) {
unsigned num_vars1 = 0, num_vars2 = 0;
for (unsigned i = 0; i < e.ls().size(); ++i) {
if (is_var(e.ls()[i])) ++num_vars1;
}
for (unsigned i = 0; i < e.rs().size(); ++i) {
if (is_var(e.rs()[i])) ++num_vars2;
}
return num_vars1 > 0 && num_vars2 > 0 && num_vars1 + num_vars2 > 2;
}
/*
\brief Decompose ls = rs into Xa = bYc, such that
1.
@ -432,8 +447,8 @@ bool theory_seq::split_lengths(dependency* dep,
SASSERT(is_var(Y));
// split_pred => X = bY1, Y = Y1Y2
SASSERT(is_split == l_true);
expr_ref Y1(mk_skolem(symbol("seq.left"), Y), m);
expr_ref Y2(mk_skolem(symbol("seq.right"), Y), m);
expr_ref Y1(mk_skolem(symbol("seq.left"), X, b, Y), m);
expr_ref Y2(mk_skolem(symbol("seq.right"), X, b, Y), m);
expr_ref bY1(m_util.str.mk_concat(b, Y1), m);
expr_ref Y1Y2(m_util.str.mk_concat(Y1, Y2), m);
literal_vector lits;
@ -657,7 +672,6 @@ lbool theory_seq::assume_equality(expr* l, expr* r) {
return l_false;
}
return ctx.get_assignment(mk_eq(l, r, false));
//return l_undef;
}
@ -2075,12 +2089,15 @@ void theory_seq::display(std::ostream & out) const {
void theory_seq::display_equations(std::ostream& out) const {
for (unsigned i = 0; i < m_eqs.size(); ++i) {
eq const& e = m_eqs[i];
out << e.ls() << " = " << e.rs() << " <- \n";
display_deps(out, e.dep());
display_equation(out, m_eqs[i]);
}
}
void theory_seq::display_equation(std::ostream& out, eq const& e) const {
out << e.ls() << " = " << e.rs() << " <- \n";
display_deps(out, e.dep());
}
void theory_seq::display_disequations(std::ostream& out) const {
bool first = true;
for (unsigned i = 0; i < m_nqs.size(); ++i) {

2
src/smt/theory_seq.h
View file

@ -373,6 +373,7 @@ namespace smt {
expr_ref_vector const& ls, expr_ref_vector const& rs,
vector<rational> const& ll, vector<rational> const& rl);
bool set_empty(expr* x);
bool is_complex(eq const& e);
bool check_extensionality();
bool check_contains();
@ -539,6 +540,7 @@ namespace smt {
// diagnostics
void display_equations(std::ostream& out) const;
void display_equation(std::ostream& out, eq const& e) const;
void display_disequations(std::ostream& out) const;
void display_disequation(std::ostream& out, ne const& e) const;
void display_deps(std::ostream& out, dependency* deps) const;