expr * reuse(set & s, func_decl * f, expr * arg1, expr * arg2) {
if (s.contains(expr_pair(arg1, arg2)))
return m().mk_app(f, arg1, arg2);
if (s.contains(expr_pair(arg2, arg1)))
return m().mk_app(f, arg2, arg1);
return 0;
}
bool matcher::operator()(expr * e1, expr * e2, substitution & s) {
reset();
m_subst = &s;
m_todo.push_back(expr_pair(e1, e2));
while (!m_todo.empty()) {
expr_pair const & p = m_todo.back();
// if (m_cache.contains(p)) {
// m_todo.pop_back();
// continue;
// }
if (is_var(p.first)) {
expr_offset r;
if (m_subst->find(to_var(p.first), 0, r)) {
if (r.get_expr() != p.second)
return false;
}
else {
m_subst->insert(to_var(p.first), 0, expr_offset(p.second, 1));
}
m_todo.pop_back();
continue;
}
if (is_var(p.second))
return false;
if (!is_app(p.first))
return false;
if (!is_app(p.second))
return false;
app * n1 = to_app(p.first);
app * n2 = to_app(p.second);
if (n1->get_decl() != n2->get_decl())
return false;
unsigned num_args1 = n1->get_num_args();
if (num_args1 != n2->get_num_args())
return false;
m_todo.pop_back();
if (num_args1 == 0)
continue;
// m_cache.insert(p);
unsigned j = num_args1;
while (j > 0) {
--j;
m_todo.push_back(expr_pair(n1->get_arg(j), n2->get_arg(j)));
}
}
return true;
}
br_status reduce_ac_app(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result) {
set & s = f2set(f);
if (num_args == 2) {
if (!m_util.is_numeral(args[0]) && !m_util.is_numeral(args[1]))
s.insert(expr_pair(args[0], args[1]));
return BR_FAILED;
}
ptr_buffer<expr, 128> _args;
bool first = false;
expr * num = 0;
for (unsigned i = 0; i < num_args; i++) {
expr * arg = args[i];
if (num == 0 && m_util.is_numeral(arg)) {
if (i == 0) first = true;
num = arg;
}
else {
_args.push_back(arg);
}
}
num_args = _args.size();
// std::sort(_args.begin(), _args.end(), ref_count_lt());
// std::sort(_args.begin(), _args.end(), ast_to_lt());
try_to_reuse:
if (num_args > 1 && num_args < m_max_args) {
for (unsigned i = 0; i < num_args - 1; i++) {
for (unsigned j = i + 1; j < num_args; j++) {
expr * r = reuse(s, f, _args[i], _args[j]);
if (r != 0) {
TRACE("bv_sharing_detail", tout << "reusing args: " << i << " " << j << "\n";);
_args[i] = r;
SASSERT(num_args > 1);
for (unsigned w = j; w < num_args - 1; w++) {
_args[w] = _args[w+1];
}
num_args--;
goto try_to_reuse;
}
}
}
