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fix setup of path constraints when the path constraint is False

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This commit is contained in:
Murphy Berzish 2018-01-24 21:25:45 -05:00
parent d9d3ef78d2
commit d648f95f63
1 changed files with 36 additions and 13 deletions
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49
src/smt/theory_str.cpp
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@ -9904,21 +9904,44 @@ namespace smt {
}
lhs_terms.push_back(ctx.mk_eq_atom(mk_strlen(str), m_autil.mk_numeral(exact_length_value, true)));
expr_ref lhs(mk_and(lhs_terms), m);
// If the automaton was built with the same polarity as the constraint,
// assert directly. Otherwise, negate the path constraint
if ( (current_assignment == l_true && assumption.get_polarity())
|| (current_assignment == l_false && !assumption.get_polarity())) {
TRACE("str", tout << "automaton and regex term have same polarity" << std::endl;);
expr_ref rhs(m.mk_and(pathConstraint, characterConstraints), m);
assert_implication(lhs, rhs);
// If the path constraint comes out as "false", this means there are no paths of that length
// in the automaton. If the polarity is the same, we can assert a conflict clause.
// If the polarity is opposite, we ignore the path constraint.
if (m.is_false(pathConstraint)) {
if ( (current_assignment == l_true && assumption.get_polarity())
|| (current_assignment == l_false && !assumption.get_polarity())) {
// automaton and constraint have same polarity -- assert conflict clause
TRACE("str", tout << "path constraint is false with matching polarity; asserting conflict clause" << std::endl;);
expr_ref conflict(m.mk_not(mk_and(lhs_terms)), m);
assert_axiom(conflict);
// don't set up "regex_terms_with_path_constraints" as a conflict clause is not a path constraint
} else {
// automaton and constraint have opposite polarity -- ignore path constraint
TRACE("str", tout << "path constraint is false with opposite polarity; ignoring path constraint" << std::endl;);
assert_implication(lhs, characterConstraints);
regex_terms_with_path_constraints.insert(str_in_re);
m_trail_stack.push(insert_obj_trail<theory_str, expr>(regex_terms_with_path_constraints, str_in_re));
}
regex_axiom_add = true;
} else {
TRACE("str", tout << "automaton and regex term have opposite polarity" << std::endl;);
expr_ref rhs(m.mk_and(m.mk_not(pathConstraint), characterConstraints), m);
assert_implication(lhs, rhs);
// If the automaton was built with the same polarity as the constraint,
// assert directly. Otherwise, negate the path constraint
if ( (current_assignment == l_true && assumption.get_polarity())
|| (current_assignment == l_false && !assumption.get_polarity())) {
TRACE("str", tout << "automaton and regex term have same polarity" << std::endl;);
expr_ref rhs(m.mk_and(pathConstraint, characterConstraints), m);
assert_implication(lhs, rhs);
} else {
TRACE("str", tout << "automaton and regex term have opposite polarity" << std::endl;);
expr_ref rhs(m.mk_and(m.mk_not(pathConstraint), characterConstraints), m);
assert_implication(lhs, rhs);
}
regex_terms_with_path_constraints.insert(str_in_re);
m_trail_stack.push(insert_obj_trail<theory_str, expr>(regex_terms_with_path_constraints, str_in_re));
regex_axiom_add = true;
}
regex_terms_with_path_constraints.insert(str_in_re);
m_trail_stack.push(insert_obj_trail<theory_str, expr>(regex_terms_with_path_constraints, str_in_re));
regex_axiom_add = true;
// increment LengthAttemptCount
regex_inc_counter(regex_length_attempt_count, re);