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enable theory propagation of regex accept condition

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-06-17 13:42:40 -07:00
parent be36a8fd80
commit 3b1149330d
4 changed files with 51 additions and 10 deletions
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41
src/smt/seq_regex.cpp
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@ -35,13 +35,30 @@ namespace smt {
arith_util& seq_regex::a() { return th.m_autil; }
void seq_regex::rewrite(expr_ref& e) { th.m_rewrite(e); }
bool seq_regex::can_propagate() const {
for (auto const& p : m_to_propagate) {
literal trigger = p.m_trigger;
if (trigger == null_literal || ctx.get_assignment(trigger) != l_undef)
return true;
}
return false;
}
bool seq_regex::propagate() {
bool change = false;
for (unsigned i = 0; !ctx.inconsistent() && i < m_to_propagate.size(); ++i) {
if (propagate(m_to_propagate[i])) {
propagation_lit const& pl = m_to_propagate[i];
literal trigger = pl.m_trigger;
if (trigger != null_literal && ctx.get_assignment(trigger) == l_undef)
continue;
if (propagate(pl.m_lit, trigger)) {
m_to_propagate.erase_and_swap(i--);
change = true;
}
else if (trigger != pl.m_trigger) {
m_to_propagate.set(i, propagation_lit(pl.m_lit, trigger));
}
}
return change;
}
@ -148,9 +165,11 @@ namespace smt {
}
void seq_regex::propagate_accept(literal lit) {
if (!propagate(lit))
m_to_propagate.push_back(lit);
}
// std::cout << "PA ";
literal t = null_literal;
if (!propagate(lit, t))
m_to_propagate.push_back(propagation_lit(lit, t));
}
/**
* Propagate the atom (accept s i r)
@ -165,7 +184,7 @@ namespace smt {
* (accept s i r) & len(s) > i => (accept s (+ i 1) D(nth(s,i), r))
*/
bool seq_regex::propagate(literal lit) {
bool seq_regex::propagate(literal lit, literal& trigger) {
SASSERT(!lit.sign());
expr* s = nullptr, *i = nullptr, *r = nullptr;
@ -173,6 +192,8 @@ namespace smt {
unsigned idx = 0;
VERIFY(sk().is_accept(e, s, i, idx, r));
// std::cout << "\nP " << idx << " " << r->get_id() << " ";
TRACE("seq", tout << "propagate " << mk_pp(e, m) << "\n";);
if (re().is_empty(r)) {
@ -185,7 +206,7 @@ namespace smt {
propagate_nullable(lit, s, idx, r);
return propagate_derivative(lit, e, s, i, idx, r);
return propagate_derivative(lit, e, s, i, idx, r, trigger);
}
/**
@ -208,6 +229,7 @@ namespace smt {
*/
void seq_regex::propagate_nullable(literal lit, expr* s, unsigned idx, expr* r) {
// std::cout << "PN ";
expr_ref is_nullable = seq_rw().is_nullable(r);
rewrite(is_nullable);
literal len_s_ge_i = th.m_ax.mk_ge(th.mk_len(s), idx);
@ -216,6 +238,8 @@ namespace smt {
}
else if (m.is_false(is_nullable)) {
th.propagate_lit(nullptr, 1, &lit, th.m_ax.mk_ge(th.mk_len(s), idx + 1));
//unsigned len = std::max(1u, re().min_length(r));
//th.propagate_lit(nullptr, 1, &lit, th.m_ax.mk_ge(th.mk_len(s), idx + re().min_length(r)));
}
else {
literal is_nullable_lit = th.mk_literal(is_nullable);
@ -237,8 +261,9 @@ namespace smt {
}
}
bool seq_regex::propagate_derivative(literal lit, expr* e, expr* s, expr* i, unsigned idx, expr* r) {
bool seq_regex::propagate_derivative(literal lit, expr* e, expr* s, expr* i, unsigned idx, expr* r, literal& trigger) {
// (accept s i R) & len(s) > i => (accept s (+ i 1) D(nth(s, i), R)) or conds
// std::cout << "PD ";
expr_ref d(m);
expr_ref head = th.mk_nth(s, i);
@ -271,6 +296,7 @@ namespace smt {
case l_undef:
#if 1
ctx.mark_as_relevant(lcond);
trigger = lcond;
return false;
#else
if (re().is_empty(tt)) {
@ -303,6 +329,7 @@ namespace smt {
conds.push_back(th.mk_literal(sk().mk_accept(s, a().mk_int(idx + 1), d)));
th.add_axiom(conds);
TRACE("seq", tout << "unfold " << head << "\n" << mk_pp(r, m) << "\n";);
// std::cout << "D ";
return true;
}