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fix internalization for quot/rem

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This commit is contained in:
Nikolaj Bjorner 2023-12-10 22:21:14 -08:00
parent 2a3cfe0cb9
commit a2d64e8441
5 changed files with 54 additions and 32 deletions
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71
src/sat/smt/polysat_internalize.cpp
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@ -192,32 +192,54 @@ namespace polysat {
void solver::internalize_udiv_i(app* e) {
expr* x, *y;
VERIFY(bv.is_bv_udivi(e, x, y) || bv.is_bv_udiv(e, x, y));
app_ref rm(bv.mk_bv_urem_i(x, y), m);
expr_ref rm(m);
if (bv.is_bv_udivi(e, x, y))
rm = bv.mk_bv_urem_i(x, y);
else if (bv.is_bv_udiv(e, x, y))
rm = bv.mk_bv_urem(x, y);
else
UNREACHABLE();
internalize(rm);
}
void solver::internalize_urem_i(app* e) {
void solver::internalize_urem_i(app* rem) {
expr* x, *y;
if (expr2enode(e))
euf::enode* n = expr2enode(rem);
SASSERT(n && n->is_attached_to(get_id()));
theory_var v = n->get_th_var(get_id());
if (m_var2pdd_valid.get(v, false))
return;
VERIFY(bv.is_bv_uremi(e, x, y) || bv.is_bv_urem(e, x, y));
auto [quot, rem] = quot_rem(x, y);
internalize_set(e, rem);
internalize_set(bv.mk_bv_udiv_i(x, y), quot);
expr_ref quot(m);
if (bv.is_bv_uremi(rem, x, y))
quot = bv.mk_bv_udiv_i(x, y);
else if (bv.is_bv_urem(rem, x, y))
quot = bv.mk_bv_udiv(x, y);
else
UNREACHABLE();
m_var2pdd_valid.setx(v, true, false);
ctx.internalize(quot);
m_var2pdd_valid.setx(v, false, false);
quot_rem(quot, rem, x, y);
}
std::pair<pdd, pdd> solver::quot_rem(expr* x, expr* y) {
void solver::quot_rem(expr* quot, expr* rem, expr* x, expr* y) {
pdd a = expr2pdd(x);
pdd b = expr2pdd(y);
euf::enode* qn = expr2enode(quot);
euf::enode* rn = expr2enode(rem);
auto& m = a.manager();
unsigned sz = m.power_of_2();
if (b.is_zero())
if (b.is_zero()) {
// By SMT-LIB specification, b = 0 ==> q = -1, r = a.
return { m.mk_val(m.max_value()), a };
if (b.is_one())
return { a, m.zero() };
internalize_set(quot, m.mk_val(m.max_value()));
internalize_set(rem, a);
return;
}
if (b.is_one()) {
internalize_set(quot, a);
internalize_set(rem, m.zero());
return;
}
if (a.is_val() && b.is_val()) {
rational const av = a.val();
@ -231,19 +253,13 @@ namespace polysat {
SASSERT(b.val() * q.val() + r.val() <= m.max_value());
SASSERT(r.val() <= (b * q + r).val());
SASSERT(r.val() < b.val());
return { std::move(q), std::move(r) };
}
internalize_set(quot, q);
internalize_set(rem, r);
return;
}
expr* quot = bv.mk_bv_udiv_i(x, y);
expr* rem = bv.mk_bv_urem_i(x, y);
ctx.internalize(quot);
ctx.internalize(rem);
auto quotv = expr2enode(quot)->get_th_var(get_id());
auto remv = expr2enode(rem)->get_th_var(get_id());
pdd q = var2pdd(quotv);
pdd r = var2pdd(remv);
pdd r = var2pdd(rn->get_th_var(get_id()));
pdd q = var2pdd(qn->get_th_var(get_id()));
// Axioms for quotient/remainder
//
@ -267,7 +283,6 @@ namespace polysat {
if (!c_eq.is_always_false())
add_polysat_clause("[axiom] quot_rem 5", { ~c_eq, m_core.eq(q + 1) }, false);
return { std::move(q), std::move(r) };
}
void solver::internalize_div_rem(app* e, bool is_div) {