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#6116 bv2int bug fix
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@NikolajBjorner
NikolajBjorner committed Sep 1, 2022
1 parent f72cdda commit 6077c41
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Showing 4 changed files with 76 additions and 29 deletions.
2 changes: 1 addition & 1 deletion src/sat/smt/arith_solver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,7 @@ namespace arith {
vector<std::pair<rational, literal>> m_literals;
svector<std::tuple<euf::enode*,euf::enode*,bool>> m_eqs;
hint_type m_ty;
unsigned m_lit_head = 0, m_lit_tail = 0, m_eq_head = 0, m_eq_tail;
unsigned m_lit_head = 0, m_lit_tail = 0, m_eq_head = 0, m_eq_tail = 0;
void reset() { m_lit_head = m_lit_tail; m_eq_head = m_eq_tail; }
void add(euf::enode* a, euf::enode* b, bool is_eq) {
if (m_eq_tail < m_eqs.size())
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10 changes: 5 additions & 5 deletions src/sat/smt/bv_internalize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -431,7 +431,7 @@ namespace bv {
sat::literal lit = eq_internalize(n, sum);
m_bv2ints.push_back(expr2enode(n));
ctx.push(push_back_vector<euf::enode_vector>(m_bv2ints));
add_unit(lit);
add_unit(lit);
}

void solver::internalize_int2bv(app* n) {
Expand Down Expand Up @@ -460,8 +460,8 @@ namespace bv {
unsigned sz = bv.get_bv_size(n);
numeral mod = power(numeral(2), sz);
rhs = m_autil.mk_mod(e, m_autil.mk_int(mod));
sat::literal eq_lit = eq_internalize(lhs, rhs);
add_unit(eq_lit);
sat::literal eq_lit = eq_internalize(lhs, rhs);
add_unit(eq_lit);

expr_ref_vector n_bits(m);
get_bits(n_enode, n_bits);
Expand All @@ -472,8 +472,8 @@ namespace bv {
rhs = m_autil.mk_mod(rhs, m_autil.mk_int(2));
rhs = mk_eq(rhs, m_autil.mk_int(1));
lhs = n_bits.get(i);
eq_lit = eq_internalize(lhs, rhs);
add_unit(eq_lit);
eq_lit = eq_internalize(lhs, rhs);
add_unit(eq_lit);
}
}

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70 changes: 53 additions & 17 deletions src/sat/smt/bv_solver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -216,10 +216,11 @@ namespace bv {
euf::enode* bv2int_arg = bv2int->get_arg(0);
for (euf::enode* p : euf::enode_parents(n1->get_root())) {
if (bv.is_int2bv(p->get_expr()) && p->get_sort() == bv2int_arg->get_sort() && p->get_root() != bv2int_arg->get_root()) {
euf::enode_pair_vector eqs;
eqs.push_back({ n1, p->get_arg(0) });
eqs.push_back({ n1, bv2int });
ctx.propagate(p, bv2int_arg, euf::th_explain::propagate(*this, eqs, p, bv2int_arg));
theory_var v1 = get_th_var(p);
theory_var v2 = get_th_var(bv2int_arg);
SASSERT(v1 != euf::null_theory_var);
SASSERT(v2 != euf::null_theory_var);
ctx.propagate(p, bv2int_arg, mk_bv2int_justification(v1, v2, n1, p->get_arg(0), bv2int));
break;
}
}
Expand Down Expand Up @@ -379,26 +380,38 @@ namespace bv {
r.push_back(b);
break;
}
case bv_justification::kind_t::bv2int: {
ctx.add_antecedent(c.a, c.b);
ctx.add_antecedent(c.a, c.c);
break;
}
}
if (!probing && ctx.use_drat())
log_drat(c);
}

void solver::log_drat(bv_justification const& c) {
// introduce dummy literal for equality.
sat::literal leq(s().num_vars() + 1, false);
expr_ref eq(m);
if (c.m_kind != bv_justification::kind_t::bit2ne) {
sat::literal leq1(s().num_vars() + 1, false);
sat::literal leq2(s().num_vars() + 2, false);
expr_ref eq1(m), eq2(m);
if (c.m_kind == bv_justification::kind_t::bv2int) {
eq1 = m.mk_eq(c.a->get_expr(), c.b->get_expr());
eq2 = m.mk_eq(c.a->get_expr(), c.c->get_expr());
ctx.set_tmp_bool_var(leq1.var(), eq1);
ctx.set_tmp_bool_var(leq2.var(), eq1);
}
else if (c.m_kind != bv_justification::kind_t::bit2ne) {
expr* e1 = var2expr(c.m_v1);
expr* e2 = var2expr(c.m_v2);
eq = m.mk_eq(e1, e2);
ctx.set_tmp_bool_var(leq.var(), eq);
eq1 = m.mk_eq(e1, e2);
ctx.set_tmp_bool_var(leq1.var(), eq1);
}

sat::literal_vector lits;
switch (c.m_kind) {
case bv_justification::kind_t::eq2bit:
lits.push_back(~leq);
lits.push_back(~leq1);
lits.push_back(~c.m_antecedent);
lits.push_back(c.m_consequent);
break;
Expand All @@ -407,17 +420,25 @@ namespace bv {
lits.push_back(c.m_consequent);
break;
case bv_justification::kind_t::bit2eq:
get_antecedents(leq, c.to_index(), lits, true);
get_antecedents(leq1, c.to_index(), lits, true);
for (auto& lit : lits)
lit.neg();
lits.push_back(leq);
lits.push_back(leq1);
break;
case bv_justification::kind_t::bit2ne:
get_antecedents(c.m_consequent, c.to_index(), lits, true);
for (auto& lit : lits)
lit.neg();
lits.push_back(c.m_consequent);
break;
case bv_justification::kind_t::bv2int:
get_antecedents(leq1, c.to_index(), lits, true);
get_antecedents(leq2, c.to_index(), lits, true);
for (auto& lit : lits)
lit.neg();
lits.push_back(leq1);
lits.push_back(leq2);
break;
}
ctx.get_drat().add(lits, status());
// TBD, a proper way would be to delete the lemma after use.
Expand Down Expand Up @@ -665,7 +686,9 @@ namespace bv {
return out << "bv <- v" << v1 << "[" << cidx << "] != v" << v2 << "[" << cidx << "] " << m_bits[v1][cidx] << " != " << m_bits[v2][cidx];
}
case bv_justification::kind_t::ne2bit:
return out << "bv <- " << m_bits[v1] << " != " << m_bits[v2] << " @" << cidx;
return out << "bv <- " << m_bits[v1] << " != " << m_bits[v2] << " @" << cidx;
case bv_justification::kind_t::bv2int:
return out << "bv <- v" << v1 << " == v" << v2 << " <== " << ctx.bpp(c.a) << " == " << ctx.bpp(c.b) << " == " << ctx.bpp(c.c);
default:
UNREACHABLE();
break;
Expand Down Expand Up @@ -818,28 +841,41 @@ namespace bv {
void* mem = get_region().allocate(bv_justification::get_obj_size());
sat::constraint_base::initialize(mem, this);
auto* constraint = new (sat::constraint_base::ptr2mem(mem)) bv_justification(v1, v2, c, a);
return sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
auto jst = sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
TRACE("bv", tout << jst << " " << constraint << "\n");
return jst;
}

sat::ext_justification_idx solver::mk_bit2eq_justification(theory_var v1, theory_var v2) {
void* mem = get_region().allocate(bv_justification::get_obj_size());
sat::constraint_base::initialize(mem, this);
auto* constraint = new (sat::constraint_base::ptr2mem(mem)) bv_justification(v1, v2);
return constraint->to_index();
auto jst = constraint->to_index();
return jst;
}

sat::justification solver::mk_bit2ne_justification(unsigned idx, sat::literal c) {
void* mem = get_region().allocate(bv_justification::get_obj_size());
sat::constraint_base::initialize(mem, this);
auto* constraint = new (sat::constraint_base::ptr2mem(mem)) bv_justification(idx, c);
return sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
auto jst = sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
return jst;
}

sat::justification solver::mk_ne2bit_justification(unsigned idx, theory_var v1, theory_var v2, sat::literal c, sat::literal a) {
void* mem = get_region().allocate(bv_justification::get_obj_size());
sat::constraint_base::initialize(mem, this);
auto* constraint = new (sat::constraint_base::ptr2mem(mem)) bv_justification(idx, v1, v2, c, a);
return sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
auto jst = sat::justification::mk_ext_justification(s().scope_lvl(), constraint->to_index());
return jst;
}

sat::ext_constraint_idx solver::mk_bv2int_justification(theory_var v1, theory_var v2, euf::enode* a, euf::enode* b, euf::enode* c) {
void* mem = get_region().allocate(bv_justification::get_obj_size());
sat::constraint_base::initialize(mem, this);
auto* constraint = new (sat::constraint_base::ptr2mem(mem)) bv_justification(v1, v2, a, b, c);
auto jst = constraint->to_index();
return jst;
}

bool solver::assign_bit(literal consequent, theory_var v1, theory_var v2, unsigned idx, literal antecedent, bool propagate_eqc) {
Expand Down
23 changes: 17 additions & 6 deletions src/sat/smt/bv_solver.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,13 +51,21 @@ namespace bv {
};

struct bv_justification {
enum kind_t { eq2bit, ne2bit, bit2eq, bit2ne };
enum kind_t { eq2bit, ne2bit, bit2eq, bit2ne, bv2int };
kind_t m_kind;
unsigned m_idx{ UINT_MAX };
theory_var m_v1{ euf::null_theory_var };
theory_var m_v2 { euf::null_theory_var };
sat::literal m_consequent;
sat::literal m_antecedent;
unsigned m_idx = UINT_MAX;
theory_var m_v1 = euf::null_theory_var;
theory_var m_v2 = euf::null_theory_var;
union {
struct {
sat::literal m_consequent;
sat::literal m_antecedent;
};
struct {
euf::enode* a, *b, *c;
};
};

bv_justification(theory_var v1, theory_var v2, sat::literal c, sat::literal a) :
m_kind(bv_justification::kind_t::eq2bit), m_v1(v1), m_v2(v2), m_consequent(c), m_antecedent(a) {}
bv_justification(theory_var v1, theory_var v2):
Expand All @@ -66,6 +74,8 @@ namespace bv {
m_kind(bv_justification::kind_t::bit2ne), m_idx(idx), m_consequent(c) {}
bv_justification(unsigned idx, theory_var v1, theory_var v2, sat::literal c, sat::literal a) :
m_kind(bv_justification::kind_t::ne2bit), m_idx(idx), m_v1(v1), m_v2(v2), m_consequent(c), m_antecedent(a) {}
bv_justification(theory_var v1, theory_var v2, euf::enode* a, euf::enode* b, euf::enode* c):
m_kind(bv_justification::kind_t::bv2int), m_v1(v1), m_v2(v2), a(a), b(b), c(c) {}
sat::ext_constraint_idx to_index() const {
return sat::constraint_base::mem2base(this);
}
Expand All @@ -79,6 +89,7 @@ namespace bv {
sat::ext_justification_idx mk_bit2eq_justification(theory_var v1, theory_var v2);
sat::justification mk_bit2ne_justification(unsigned idx, sat::literal c);
sat::justification mk_ne2bit_justification(unsigned idx, theory_var v1, theory_var v2, sat::literal c, sat::literal a);
sat::ext_constraint_idx mk_bv2int_justification(theory_var v1, theory_var v2, euf::enode* a, euf::enode* b, euf::enode* c);
void log_drat(bv_justification const& c);


Expand Down

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