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add handling for int.to.str

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-04-18 11:14:40 -07:00
parent 5d0db6d256
commit 4761f4f191
3 changed files with 79 additions and 0 deletions
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66
src/smt/theory_seq.cpp
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@ -202,6 +202,7 @@ theory_seq::theory_seq(ast_manager& m):
m_exclude(m),
m_axioms(m),
m_axioms_head(0),
m_int_string(m),
m_mg(0),
m_rewrite(m),
m_seq_rewrite(m),
@ -257,6 +258,11 @@ final_check_status theory_seq::final_check_eh() {
TRACE("seq", tout << ">>fixed_length\n";);
return FC_CONTINUE;
}
if (check_int_string()) {
++m_stats.m_int_string;
TRACE("seq", tout << ">>int_string\n";);
return FC_CONTINUE;
}
if (reduce_length_eq() || branch_unit_variable() || branch_binary_variable() || branch_variable_mb() || branch_variable()) {
++m_stats.m_branch_variable;
TRACE("seq", tout << ">>branch_variable\n";);
@ -2160,6 +2166,7 @@ void theory_seq::add_length(expr* e) {
m_trail_stack.push(insert_obj_trail<theory_seq, expr>(m_length, e));
}
/*
ensure that all elements in equivalence class occur under an applicatin of 'length'
*/
@ -2177,6 +2184,48 @@ void theory_seq::enforce_length(enode* n) {
while (n1 != n);
}
void theory_seq::add_int_string(expr* e) {
m_int_string.push_back(e);
m_trail_stack.push(push_back_vector<theory_seq, expr_ref_vector>(m_int_string));
}
bool theory_seq::check_int_string() {
bool change = false;
for (unsigned i = 0; i < m_int_string.size(); ++i) {
expr* e = m_int_string[i].get(), *n;
if (add_itos_axiom(e)) {
change = true;
}
else if (m_util.str.is_stoi(e, n)) {
// not (yet) handled.
// we would check that in the current proto-model
// the string at 'n', when denoting integer would map to the
// proper integer.
}
}
return change;
}
bool theory_seq::add_itos_axiom(expr* e) {
context& ctx = get_context();
rational val;
expr* n;
if (m_util.str.is_itos(e, n) && get_value(n, val)) {
app_ref e1(m_util.str.mk_string(symbol(val.to_string().c_str())), m);
if (!m_itos_axioms.contains(val)) {
m_itos_axioms.insert(val);
expr_ref n1(arith_util(m).mk_numeral(val, true), m);
add_axiom(mk_eq(m_util.str.mk_itos(n1), e1, false));
m_trail_stack.push(insert_map<theory_seq, rational_set, rational>(m_itos_axioms, val));
m_trail_stack.push(push_replay(alloc(replay_axiom, m, e)));
return true;
}
}
return false;
}
void theory_seq::apply_sort_cnstr(enode* n, sort* s) {
mk_var(n);
}
@ -2317,6 +2366,7 @@ void theory_seq::collect_statistics(::statistics & st) const {
st.update("seq add axiom", m_stats.m_add_axiom);
st.update("seq extensionality", m_stats.m_extensionality);
st.update("seq fixed length", m_stats.m_fixed_length);
st.update("seq int.to.str", m_stats.m_int_string);
}
void theory_seq::init_model(expr_ref_vector const& es) {
@ -2627,6 +2677,9 @@ void theory_seq::deque_axiom(expr* n) {
else if (m_util.str.is_string(n)) {
add_elim_string_axiom(n);
}
else if (m_util.str.is_itos(n)) {
add_itos_axiom(n);
}
}
@ -2890,6 +2943,14 @@ static theory_mi_arith* get_th_arith(context& ctx, theory_id afid, expr* e) {
}
}
bool theory_seq::get_value(expr* e, rational& val) const {
context& ctx = get_context();
theory_mi_arith* tha = get_th_arith(ctx, m_autil.get_family_id(), e);
expr_ref _val(m);
if (!tha || !tha->get_value(ctx.get_enode(e), _val)) return false;
return m_autil.is_numeral(_val, val) && val.is_int();
}
bool theory_seq::lower_bound(expr* _e, rational& lo) const {
context& ctx = get_context();
expr_ref e(m_util.str.mk_length(_e), m);
@ -3525,6 +3586,11 @@ void theory_seq::relevant_eh(app* n) {
enque_axiom(n);
}
if (m_util.str.is_itos(n) ||
m_util.str.is_stoi(n)) {
add_int_string(n);
}
expr* arg;
if (m_util.str.is_length(n, arg) && !has_length(arg)) {
enforce_length(get_context().get_enode(arg));