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properly handle recursive function definitions #898

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-03-24 10:10:42 -07:00
parent 3bbe5eceeb
commit e05cee757b
5 changed files with 12 additions and 32 deletions
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32
src/smt/smt_context.cpp
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@ -4217,40 +4217,18 @@ namespace smt {
TRACE("context", tout << mk_pp(e, m) << "\n";);
quantifier* q = to_quantifier(e);
if (!m.is_rec_fun_def(q)) continue;
SASSERT(q->get_num_patterns() == 1);
SASSERT(q->get_num_patterns() == 2);
expr* fn = to_app(q->get_pattern(0))->get_arg(0);
expr* body = to_app(q->get_pattern(1))->get_arg(0);
SASSERT(is_app(fn));
func_decl* f = to_app(fn)->get_decl();
expr* eq = q->get_expr();
expr_ref body(m);
if (is_fun_def(fn, q->get_expr(), body)) {
func_interp* fi = alloc(func_interp, m, f->get_arity());
fi->set_else(body);
m_model->register_decl(f, fi);
}
func_interp* fi = alloc(func_interp, m, f->get_arity());
fi->set_else(body);
m_model->register_decl(f, fi);
}
}
}
bool context::is_fun_def(expr* f, expr* body, expr_ref& result) {
expr* t1, *t2, *t3;
if (m_manager.is_eq(body, t1, t2) || m_manager.is_iff(body, t1, t2)) {
if (t1 == f) return result = t2, true;
if (t2 == f) return result = t1, true;
return false;
}
if (m_manager.is_ite(body, t1, t2, t3)) {
expr_ref body1(m_manager), body2(m_manager);
if (is_fun_def(f, t2, body1) && is_fun_def(f, t3, body2)) {
// f is not free in t1
result = m_manager.mk_ite(t1, body1, body2);
return true;
}
}
return false;
}
};