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fix #4871

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This commit is contained in:
Nikolaj Bjorner 2020-12-07 22:07:30 -08:00
parent c49d39af81
commit 9b9d906702
1 changed files with 19 additions and 15 deletions
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34
src/tactic/core/solve_eqs_tactic.cpp
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@ -321,23 +321,27 @@ class solve_eqs_tactic : public tactic {
bool solve_mod(expr * lhs, expr * rhs, expr * eq, app_ref & var, expr_ref & def, proof_ref & pr) {
rational r1, r2;
expr* arg1, *arg2, *arg3, *arg4;
if (m_produce_proofs) {
expr* arg1;
if (m_produce_proofs)
return false;
auto fresh = [&]() { return m().mk_fresh_const("mod", m_a_util.mk_int()); };
auto mk_int = [&](rational const& r) { return m_a_util.mk_int(r); };
auto add = [&](expr* a, expr* b) { return m_a_util.mk_add(a, b); };
auto mul = [&](expr* a, expr* b) { return m_a_util.mk_mul(a, b); };
VERIFY(m_a_util.is_mod(lhs, lhs, arg1));
if (!m_a_util.is_numeral(arg1, r1) || !r1.is_pos()) {
return false;
}
VERIFY(m_a_util.is_mod(lhs, arg1, arg2));
if (!m_a_util.is_numeral(arg2, r1) || !r1.is_pos()) {
return false;
}
if (m_a_util.is_mod(rhs, arg3, arg4) && m_a_util.is_numeral(arg4, r2) && r1 == r2) {
rhs = arg3;
}
else if (!m_a_util.is_numeral(rhs, r2) || !r2.is_zero()) {
return false;
}
if (solve_eq(arg1, rhs, eq, var, def, pr)) {
def = m_a_util.mk_add(def, m_a_util.mk_mul(m().mk_fresh_const("mod", m_a_util.mk_int()), m_a_util.mk_int(r1)));
return true;
//
// solve lhs mod r1 = r2
// as lhs = r1*mod!1 + r2
//
if (m_a_util.is_numeral(rhs, r2) && r2 < r1) {
expr_ref def0(m());
def0 = add(mk_int(r2), mul(fresh(), mk_int(r1)));
return solve_eq(lhs, def0, eq, var, def, pr);
}
return false;
}