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fix axioms for extract, add extensionality checking for shared variables, convert exceptions to unknown status per #419

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2016-01-18 11:09:41 +05:30
parent 88362a1c3a
commit 85d44c5d66
17 changed files with 110 additions and 13 deletions
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51
src/smt/theory_seq.cpp
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@ -221,6 +221,11 @@ final_check_status theory_seq::final_check_eh() {
TRACE("seq", tout << ">>propagate_automata\n";);
return FC_CONTINUE;
}
if (!check_extensionality()) {
++m_stats.m_extensionality;
TRACE("seq", tout << ">>extensionality\n";);
return FC_CONTINUE;
}
if (is_solved()) {
TRACE("seq", tout << ">>is_solved\n";);
return FC_DONE;
@ -541,6 +546,45 @@ void theory_seq::mk_decompose(expr* e, expr_ref& head, expr_ref& tail) {
}
}
/*
\brief Check extensionality (for sequences).
*/
bool theory_seq::check_extensionality() {
context& ctx = get_context();
unsigned sz = get_num_vars();
unsigned_vector seqs;
bool added_assumption = false;
for (unsigned v = 0; v < sz; ++v) {
enode* n = get_enode(v);
expr* o1 = n->get_owner();
if (n != n->get_root()) {
continue;
}
if (!seqs.empty() && ctx.is_relevant(n) && m_util.is_seq(o1) && ctx.is_shared(n)) {
dependency* dep = 0;
expr_ref e1 = canonize(o1, dep);
for (unsigned i = 0; i < seqs.size(); ++i) {
enode* n2 = get_enode(seqs[i]);
expr* o2 = n2->get_owner();
if (m_exclude.contains(o1, o2)) {
continue;
}
expr_ref e2 = canonize(n2->get_owner(), dep);
m_lhs.reset(); m_rhs.reset();
bool change = false;
if (!m_seq_rewrite.reduce_eq(o1, o2, m_lhs, m_rhs, change)) {
m_exclude.update(o1, o2);
continue;
}
TRACE("seq", tout << mk_pp(o1, m) << " = " << mk_pp(o2, m) << "\n";);
ctx.assume_eq(n, n2);
return false;
}
}
seqs.push_back(v);
}
return true;
}
/*
- Eqs = 0
@ -1248,6 +1292,7 @@ void theory_seq::collect_statistics(::statistics & st) const {
st.update("seq solve !=", m_stats.m_solve_nqs);
st.update("seq solve =", m_stats.m_solve_eqs);
st.update("seq add axiom", m_stats.m_add_axiom);
st.update("seq extensionality", m_stats.m_extensionality);
}
void theory_seq::init_model(expr_ref_vector const& es) {
@ -1917,18 +1962,18 @@ void theory_seq::add_extract_axiom(expr* e) {
expr_ref ls(m_util.str.mk_length(s), m);
expr_ref lx(m_util.str.mk_length(x), m);
expr_ref le(m_util.str.mk_length(e), m);
expr_ref ls_minus_i(mk_sub(ls, i), m);
expr_ref ls_minus_i_l(mk_sub(mk_sub(ls, i),l), m);
expr_ref xe = mk_concat(x, e);
expr_ref zero(m_autil.mk_int(0), m);
literal i_ge_0 = mk_literal(m_autil.mk_ge(i, zero));
literal i_ge_ls = mk_literal(m_autil.mk_ge(mk_sub(i, ls), zero));
literal l_ge_ls = mk_literal(m_autil.mk_ge(mk_sub(l, ls), zero));
literal li_ge_ls = mk_literal(m_autil.mk_ge(ls_minus_i_l, zero));
literal l_ge_zero = mk_literal(m_autil.mk_ge(l, zero));
add_axiom(~i_ge_0, i_ge_ls, mk_literal(m_util.str.mk_prefix(xe, s)));
add_axiom(~i_ge_0, i_ge_ls, mk_eq(lx, i, false));
add_axiom(~i_ge_0, i_ge_ls, ~l_ge_ls, mk_eq(le, ls_minus_i, false));
add_axiom(~i_ge_0, i_ge_ls, ~li_ge_ls, mk_eq(le, l, false));
add_axiom(~i_ge_0, i_ge_ls, l_ge_zero, mk_eq(le, zero, false));
}