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fixes to intblast encoding and more arithmetic rewriters

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2023-12-17 18:15:51 -08:00
parent bb99f44214
commit 2f2bf749b9
3 changed files with 46 additions and 17 deletions
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52
src/ast/rewriter/arith_rewriter.cpp
View file

@ -1232,19 +1232,20 @@ static rational symmod(rational const& a, rational const& b) {
br_status arith_rewriter::mk_mod_core(expr * arg1, expr * arg2, expr_ref & result) {
set_curr_sort(arg1->get_sort());
numeral v1, v2;
bool is_int;
if (m_util.is_numeral(arg1, v1, is_int) && m_util.is_numeral(arg2, v2, is_int) && !v2.is_zero()) {
result = m_util.mk_numeral(mod(v1, v2), is_int);
numeral x, y;
bool is_num_x = m_util.is_numeral(arg1, x);
bool is_num_y = m_util.is_numeral(arg2, y);
if (is_num_x && is_num_y && !y.is_zero()) {
result = m_util.mk_int(mod(x, y));
return BR_DONE;
}
if (m_util.is_numeral(arg2, v2, is_int) && is_int && (v2.is_one() || v2.is_minus_one())) {
if (is_num_y && y.is_int() && (y.is_one() || y.is_minus_one())) {
result = m_util.mk_numeral(numeral(0), true);
return BR_DONE;
}
if (arg1 == arg2 && !m_util.is_numeral(arg2)) {
if (arg1 == arg2 && !is_num_y) {
expr_ref zero(m_util.mk_int(0), m);
result = m.mk_ite(m.mk_eq(arg2, zero), m_util.mk_mod(zero, zero), zero);
return BR_DONE;
@ -1252,29 +1253,35 @@ br_status arith_rewriter::mk_mod_core(expr * arg1, expr * arg2, expr_ref & resul
// mod is idempotent on non-zero modulus.
expr* t1, *t2;
if (m_util.is_mod(arg1, t1, t2) && t2 == arg2 && m_util.is_numeral(arg2, v2, is_int) && is_int && !v2.is_zero()) {
if (m_util.is_mod(arg1, t1, t2) && t2 == arg2 && is_num_y && y.is_int() && !y.is_zero()) {
result = arg1;
return BR_DONE;
}
rational lo, hi;
if (is_num_y && get_range(arg1, lo, hi) && 0 <= lo && hi < y) {
result = arg1;
return BR_DONE;
}
// propagate mod inside only if there is something to reduce.
if (m_util.is_numeral(arg2, v2, is_int) && is_int && v2.is_pos() && (is_add(arg1) || is_mul(arg1))) {
if (is_num_y && y.is_int() && y.is_pos() && (is_add(arg1) || is_mul(arg1))) {
TRACE("mod_bug", tout << "mk_mod:\n" << mk_ismt2_pp(arg1, m) << "\n" << mk_ismt2_pp(arg2, m) << "\n";);
expr_ref_buffer args(m);
bool change = false;
for (expr* arg : *to_app(arg1)) {
rational arg_v;
if (m_util.is_numeral(arg, arg_v) && mod(arg_v, v2) != arg_v) {
if (m_util.is_numeral(arg, arg_v) && mod(arg_v, y) != arg_v) {
change = true;
args.push_back(m_util.mk_numeral(mod(arg_v, v2), true));
args.push_back(m_util.mk_numeral(mod(arg_v, y), true));
}
else if (m_util.is_mod(arg, t1, t2) && t2 == arg2) {
change = true;
args.push_back(t1);
}
else if (m_util.is_mul(arg, t1, t2) && m_util.is_numeral(t1, arg_v) && symmod(arg_v, v2) != arg_v) {
else if (m_util.is_mul(arg, t1, t2) && m_util.is_numeral(t1, arg_v) && symmod(arg_v, y) != arg_v) {
change = true;
args.push_back(m_util.mk_mul(m_util.mk_numeral(symmod(arg_v, v2), true), t2));
args.push_back(m_util.mk_mul(m_util.mk_numeral(symmod(arg_v, y), true), t2));
}
else {
args.push_back(arg);
@ -1291,6 +1298,27 @@ br_status arith_rewriter::mk_mod_core(expr * arg1, expr * arg2, expr_ref & resul
return BR_FAILED;
}
bool arith_rewriter::get_range(expr* e, rational& lo, rational& hi) {
expr* x, *y;
rational r;
if (m_util.is_idiv(e, x, y) && m_util.is_numeral(y, r) && get_range(x, lo, hi) && 0 <= lo && r > 0) {
lo = div(lo, r);
hi = div(hi, r);
return true;
}
if (m_util.is_mod(e, x, y) && m_util.is_numeral(y, r) && r > 0) {
lo = 0;
hi = r - 1;
return true;
}
if (m_util.is_numeral(e, r)) {
lo = hi = r;
return true;
}
return false;
}
br_status arith_rewriter::mk_rem_core(expr * arg1, expr * arg2, expr_ref & result) {
set_curr_sort(arg1->get_sort());
numeral v1, v2;

1
src/ast/rewriter/arith_rewriter.h
View file

@ -63,6 +63,7 @@ class arith_rewriter : public poly_rewriter<arith_rewriter_core> {
bool m_eq2ineq;
unsigned m_max_degree;
bool get_range(expr* e, rational& lo, rational& hi);
void get_coeffs_gcd(expr * t, numeral & g, bool & first, unsigned & num_consts);
enum const_treatment { CT_FLOOR, CT_CEIL, CT_FALSE };
bool div_polynomial(expr * t, numeral const & g, const_treatment ct, expr_ref & result);

10
src/sat/smt/intblast_solver.cpp
View file

@ -37,7 +37,6 @@ namespace intblast {
euf::theory_var solver::mk_var(euf::enode* n) {
auto r = euf::th_euf_solver::mk_var(n);
ctx.attach_th_var(n, this, r);
TRACE("bv", tout << "mk-var: v" << r << " " << ctx.bpp(n) << "\n";);
return r;
}
@ -98,7 +97,7 @@ namespace intblast {
ensure_translated(y);
m_args.reset();
m_args.push_back(a.mk_sub(translated(x), translated(y)));
set_translated(e, m.mk_eq(umod(x, 0), a.mk_int(0)));
set_translated(e, m.mk_eq(umod(x, 0), a.mk_int(0)));
}
m_preds.push_back(e);
ctx.push(push_back_vector(m_preds));
@ -148,7 +147,7 @@ namespace intblast {
auto a = expr2literal(e);
auto b = mk_literal(r);
ctx.mark_relevant(b);
// verbose_stream() << "add-predicate-axiom: " << mk_pp(e, m) << " == " << r << "\n";
TRACE("intblast", tout << "add-predicate-axiom: " << mk_bounded_pp(e, m) << " \n" << r << "\n");
add_equiv(a, b);
}
return true;
@ -606,9 +605,10 @@ namespace intblast {
unsigned lo, hi;
expr* old_arg;
VERIFY(bv.is_extract(e, lo, hi, old_arg));
r = arg(0);
if (lo > 0)
r = a.mk_idiv(r, a.mk_int(rational::power_of_two(lo)));
r = a.mk_idiv(umod(old_arg, 0), a.mk_int(rational::power_of_two(lo)));
else
r = arg(0);
break;
}
case OP_BV_NUM: {