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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-04-19 12:00:38 -07:00
parent 19e0285b83
commit 79b776fee5
4 changed files with 48 additions and 35 deletions
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37
src/smt/theory_seq.cpp
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@ -3054,7 +3054,10 @@ void theory_seq::enque_axiom(expr* e) {
void theory_seq::deque_axiom(expr* n) {
TRACE("seq", tout << "deque: " << mk_bounded_pp(n, m, 2) << "\n";);
if (m_util.str.is_length(n)) {
add_length_axiom(n);
m_ax.add_length_axiom(n);
if (!get_context().at_base_level()) {
m_trail_stack.push(push_replay(alloc(replay_axiom, m, n)));
}
}
else if (m_util.str.is_empty(n) && !has_length(n) && !m_has_length.empty()) {
add_length_to_eqc(n);
@ -3116,38 +3119,6 @@ expr_ref theory_seq::add_elim_string_axiom(expr* n) {
return result;
}
/*
let n = len(x)
- len(a ++ b) = len(a) + len(b) if x = a ++ b
- len(unit(u)) = 1 if x = unit(u)
- len(str) = str.length() if x = str
- len(empty) = 0 if x = empty
- len(int.to.str(i)) >= 1 if x = int.to.str(i) and more generally if i = 0 then 1 else 1+floor(log(|i|))
- len(x) >= 0 otherwise
*/
void theory_seq::add_length_axiom(expr* n) {
context& ctx = get_context();
expr* x = nullptr;
VERIFY(m_util.str.is_length(n, x));
if (m_util.str.is_concat(x) ||
m_util.str.is_unit(x) ||
m_util.str.is_empty(x) ||
m_util.str.is_string(x)) {
expr_ref len(n, m);
m_rewrite(len);
SASSERT(n != len);
add_axiom(mk_eq(len, n, false));
}
else {
add_axiom(mk_literal(m_autil.mk_ge(n, m_autil.mk_int(0))));
}
if (!ctx.at_base_level()) {
m_trail_stack.push(push_replay(alloc(replay_axiom, m, n)));
}
}
void theory_seq::propagate_in_re(expr* n, bool is_true) {
TRACE("seq", tout << mk_pp(n, m) << " <- " << (is_true?"true":"false") << "\n";);