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separate fixed from bits to allow updates that break tabu

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- range and fixed restrictions on terms are based on constraints and can be violated temporarily.
- bv_eval currently does not allow updating over fixed bits which leads to non-termination. TODO
- lookahead only considers tabu when setting values of variables.
This commit is contained in:
Nikolaj Bjorner 2024-12-30 17:47:18 -08:00
parent 983763213b
commit 3433b14dfa
10 changed files with 224 additions and 193 deletions
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159
src/ast/sls/sls_bv_fixed.cpp
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@ -8,7 +8,7 @@ Module Name:
Author:
Nikolaj Bjorner (nbjorner) 2024-02-07
--*/
#include "ast/ast_pp.h"
@ -19,15 +19,18 @@ Author:
namespace sls {
bv_fixed::bv_fixed(bv_eval& ev, bv_terms& terms, sls::context& ctx):
bv_fixed::bv_fixed(bv_eval& ev, bv_terms& terms, sls::context& ctx) :
ev(ev),
terms(terms),
m(ev.m),
bv(ev.bv),
ctx(ctx)
{}
{
}
void bv_fixed::init() {
void bv_fixed::init() {
return;
for (auto e : ctx.subterms())
set_fixed(e);
@ -40,12 +43,12 @@ namespace sls {
continue;
if (is_app(a))
init_range(to_app(a), lit.sign());
ev.m_fixed.setx(a->get_id(), true, false);
ev.m_is_fixed.setx(a->get_id(), true, false);
}
//ctx.display(verbose_stream());
for (auto e : ctx.subterms())
propagate_range_up(e);
propagate_range_up(e);
//ctx.display(verbose_stream());
}
@ -64,24 +67,24 @@ namespace sls {
auto p = rational::power_of_two(bv.get_bv_size(s));
add_range(e, valt.lo() * p, valt.hi() * p, false);
}
}
}
else if (bv.is_bv_add(e, s, t) && bv.is_numeral(s, v)) {
auto& val = ev.wval(t);
if (val.lo() != val.hi())
add_range(e, v + val.lo(), v + val.hi(), false);
if (val.lo() != val.hi())
add_range(e, v + val.lo(), v + val.hi(), false);
}
else if (bv.is_bv_add(e, t, s) && bv.is_numeral(s, v)) {
auto& val = ev.wval(t);
if (val.lo() != val.hi())
add_range(e, v + val.lo(), v + val.hi(), false);
if (val.lo() != val.hi())
add_range(e, v + val.lo(), v + val.hi(), false);
}
// x in [1, 4[ => -x in [-3, 0[
// x in [lo, hi[ => -x in [-hi + 1, -lo + 1[
else if (bv.is_bv_mul(e, s, t) && bv.is_numeral(s, v) &&
else if (bv.is_bv_mul(e, s, t) && bv.is_numeral(s, v) &&
v + 1 == rational::power_of_two(bv.get_bv_size(e))) {
auto& val = ev.wval(t);
if (val.lo() != val.hi())
add_range(e, -val.hi() + 1, - val.lo() + 1, false);
add_range(e, -val.hi() + 1, -val.lo() + 1, false);
}
}
@ -94,7 +97,7 @@ namespace sls {
auto N = [&](expr* s) {
auto b = bv.get_bv_size(s);
return b > 0 ? rational::power_of_two(b - 1) : rational(0);
};
};
if (bv.is_ule(e, s, t)) {
get_offset(s, x, a);
get_offset(t, y, b);
@ -104,22 +107,22 @@ namespace sls {
get_offset(s, x, a);
get_offset(t, y, b);
return init_range(y, b, x, a, !sign);
}
}
else if (bv.is_uge(e, s, t)) {
get_offset(s, x, a);
get_offset(t, y, b);
return init_range(y, b, x, a, sign);
}
}
else if (bv.is_ugt(e, s, t)) {
get_offset(s, x, a);
get_offset(t, y, b);
return init_range(x, a, y, b, !sign);
}
}
else if (bv.is_sle(e, s, t)) {
get_offset(s, x, a);
get_offset(t, y, b);
return init_range(x, a + N(s), y, b + N(s), sign);
}
}
else if (bv.is_slt(e, s, t)) {
get_offset(s, x, a);
get_offset(t, y, b);
@ -147,7 +150,7 @@ namespace sls {
else if (bv.is_bit2bool(e, s, idx)) {
auto& val = ev.wval(s);
val.try_set_bit(idx, !sign);
val.fixed.set(idx, true);
val.set_fixed_bit(idx, !sign);
val.tighten_range();
return true;
}
@ -155,10 +158,10 @@ namespace sls {
return false;
}
bool bv_fixed::init_eq(expr* t, rational const& a, bool sign) {
bool bv_fixed::init_eq(expr* t, rational const& a, bool sign) {
unsigned lo, hi;
rational b(0);
expr* s = nullptr;
expr* s = nullptr;
if (sign && true)
// 1 <= t - a
init_range(nullptr, rational(1), t, -a, false);
@ -185,19 +188,19 @@ namespace sls {
if (hi == lo) {
auto sign1 = sign ? a == 1 : a == 0;
auto& val = ev.wval(s);
if (val.try_set_bit(lo, !sign1))
val.fixed.set(lo, true);
val.try_set_bit(lo, !sign1);
val.set_fixed_bit(lo, !sign1);
val.tighten_range();
}
else if (!sign) {
auto& val = ev.wval(s);
for (unsigned i = lo; i <= hi; ++i)
if (val.try_set_bit(i, a.get_bit(i - lo)))
val.fixed.set(i, true);
for (unsigned i = lo; i <= hi; ++i) {
val.try_set_bit(i, a.get_bit(i - lo));
val.set_fixed_bit(i, a.get_bit(i - lo));
}
val.tighten_range();
}
}
if (!sign && hi + 1 == bv.get_bv_size(s)) {
// s < 2^lo * (a + 1)
@ -223,11 +226,11 @@ namespace sls {
bool bv_fixed::init_range(expr* x, rational const& a, expr* y, rational const& b, bool sign) {
if (!x && !y)
return false;
if (!x)
if (!x)
return add_range(y, a - b, -b, sign);
else if (!y)
return add_range(x, -a, b - a + 1, sign);
else if (x == y)
else if (!y)
return add_range(x, -a, b - a + 1, sign);
else if (x == y)
return add_range(x, -a, -b, sign);
return false;
}
@ -240,6 +243,7 @@ namespace sls {
return false;
if (sign)
std::swap(lo, hi);
rational r;
v.add_range(lo, hi);
expr* x, * y;
if (v.lo() == 0 && bv.is_concat(e, x, y)) {
@ -256,6 +260,15 @@ namespace sls {
add_range(x, lo, hi, false);
}
}
else if (bv.is_bv_mul(e, x, y) &&
hi != lo &&
bv.is_numeral(x, r) &&
r + 1 == rational::power_of_two(bv.get_bv_size(e))) {
add_range(y, 1 - hi, 1 - lo, false);
}
else if (bv.is_bv_add(e, x, y) && bv.is_numeral(x, r)) {
add_range(y, lo - r, hi - r, false);
}
return true;
}
@ -287,19 +300,19 @@ namespace sls {
return false;
return all_of(*e, [&](expr* arg) { return ev.is_fixed0(arg); });
}
void bv_fixed::set_fixed(expr* _e) {
if (!is_app(_e))
return;
auto e = to_app(_e);
if (e->get_family_id() == bv.get_family_id() && all_of(*e, [&](expr* arg) { return ev.is_fixed0(arg); })) {
if (bv.is_bv(e)) {
if (bv.is_bv(e)) {
auto& v = ev.wval(e);
for (unsigned i = 0; i < v.bw; ++i)
v.fixed.set(i, true);
v.set_fixed_bit(i, v.bits().get(i));
}
ev.m_fixed.setx(e->get_id(), true, false);
ev.m_is_fixed.setx(e->get_id(), true, false);
return;
}
@ -310,9 +323,11 @@ namespace sls {
if (m.is_ite(e)) {
auto& val_th = ev.wval(e->get_arg(1));
auto& val_el = ev.wval(e->get_arg(2));
for (unsigned i = 0; i < v.nw; ++i)
v.fixed[i] = val_el.fixed[i] & val_th.fixed[i] & ~(val_el.bits(i) ^ val_th.bits(i));
return;
for (unsigned i = 0; i < v.nw; ++i) {
auto mask = val_el.fixed(i) & val_th.fixed(i) & ~(val_el.bits(i) ^ val_th.bits(i));
v.set_fixed_word(i, mask, v.bits(i));
return;
}
}
if (e->get_family_id() != bv.get_fid())
@ -323,8 +338,10 @@ namespace sls {
auto& a = ev.wval(e->get_arg(0));
auto& b = ev.wval(e->get_arg(1));
// (a.fixed & b.fixed) | (a.fixed & ~a.bits) | (b.fixed & ~b.bits)
for (unsigned i = 0; i < a.nw; ++i)
v.fixed[i] = (a.fixed[i] & b.fixed[i]) | (a.fixed[i] & ~a.bits(i)) | (b.fixed[i] & ~b.bits(i));
for (unsigned i = 0; i < a.nw; ++i) {
auto mask = (a.fixed(i) & b.fixed(i)) | (a.fixed(i) & ~a.bits(i)) | (b.fixed(i) & ~b.bits(i));
v.set_fixed_word(i, mask, v.bits(i));
}
}
break;
}
@ -333,8 +350,10 @@ namespace sls {
auto& a = ev.wval(e->get_arg(0));
auto& b = ev.wval(e->get_arg(1));
// (a.fixed & b.fixed) | (a.fixed & a.bits) | (b.fixed & b.bits)
for (unsigned i = 0; i < a.nw; ++i)
v.fixed[i] = (a.fixed[i] & b.fixed[i]) | (a.fixed[i] & a.bits(i)) | (b.fixed[i] & b.bits(i));
for (unsigned i = 0; i < a.nw; ++i) {
auto mask = (a.fixed(i) & b.fixed(i)) | (a.fixed(i) & a.bits(i)) | (b.fixed(i) & b.bits(i));
v.set_fixed_word(i, mask, v.bits(i));
}
}
break;
}
@ -343,14 +362,14 @@ namespace sls {
auto& a = ev.wval(e->get_arg(0));
auto& b = ev.wval(e->get_arg(1));
for (unsigned i = 0; i < a.nw; ++i)
v.fixed[i] = a.fixed[i] & b.fixed[i];
v.set_fixed_word(i, a.fixed(i) & b.fixed(i), v.bits(i));
}
break;
}
case OP_BNOT: {
auto& a = ev.wval(e->get_arg(0));
for (unsigned i = 0; i < a.nw; ++i)
v.fixed[i] = a.fixed[i];
v.set_fixed_word(i, a.fixed(i), v.bits(i));
break;
}
case OP_BADD: {
@ -358,9 +377,10 @@ namespace sls {
for (unsigned i = 0; i < v.bw; ++i) {
for (unsigned j = 0; pfixed && j < e->get_num_args(); ++j) {
auto& a = ev.wval(e->get_arg(j));
pfixed &= a.fixed.get(i);
pfixed &= a.fixed().get(i);
}
v.fixed.set(i, pfixed);
if (pfixed)
v.set_fixed_bit(i, v.get_bit(i));
}
break;
}
@ -373,36 +393,36 @@ namespace sls {
// i'th bit depends on bits j + k = i
// if the first j, resp k bits are 0, the bits j + k are 0
for (; j < v.bw; ++j)
if (!a.fixed.get(j))
if (!a.fixed().get(j))
break;
for (; k < v.bw; ++k)
if (!b.fixed.get(k))
if (!b.fixed().get(k))
break;
for (; zj < v.bw; ++zj)
if (!a.fixed.get(zj) || a.get_bit(zj))
if (!a.fixed().get(zj) || a.get_bit(zj))
break;
for (; zk < v.bw; ++zk)
if (!b.fixed.get(zk) || b.get_bit(zk))
if (!b.fixed().get(zk) || b.get_bit(zk))
break;
for (; hzj < v.bw; ++hzj)
if (!a.fixed.get(v.bw - hzj - 1) || a.get_bit(v.bw - hzj - 1))
if (!a.fixed().get(v.bw - hzj - 1) || a.get_bit(v.bw - hzj - 1))
break;
for (; hzk < v.bw; ++hzk)
if (!b.fixed.get(v.bw - hzk - 1) || b.get_bit(v.bw - hzk - 1))
if (!b.fixed().get(v.bw - hzk - 1) || b.get_bit(v.bw - hzk - 1))
break;
if (j > 0 && k > 0) {
for (unsigned i = 0; i < std::min(k, j); ++i) {
SASSERT(!v.get_bit(i));
v.fixed.set(i, true);
v.set_fixed_bit(i, false);
}
}
// lower zj + jk bits are 0
if (zk > 0 || zj > 0) {
for (unsigned i = 0; i < zk + zj; ++i) {
SASSERT(!v.get_bit(i));
v.fixed.set(i, true);
v.set_fixed_bit(i, false);
}
}
// upper bits are 0, if enough high order bits of a, b are 0.
@ -412,7 +432,7 @@ namespace sls {
hzk = v.bw - hzk;
for (unsigned i = hzj + hzk - 1; i < v.bw; ++i) {
SASSERT(!v.get_bit(i));
v.fixed.set(i, true);
v.set_fixed_bit(i, false);
}
}
}
@ -421,9 +441,10 @@ namespace sls {
for (unsigned i = 0; i < v.bw; ++i) {
for (unsigned j = 0; pfixed && j < e->get_num_args(); ++j) {
auto& a = ev.wval(e->get_arg(j));
pfixed &= a.fixed.get(i);
pfixed &= a.fixed().get(i);
}
v.fixed.set(i, pfixed);
if (pfixed)
v.set_fixed_bit(i, v.get_bit(i));
}
}
break;
@ -433,7 +454,8 @@ namespace sls {
for (unsigned i = e->get_num_args(); i-- > 0; ) {
auto& a = ev.wval(e->get_arg(i));
for (unsigned j = 0; j < a.bw; ++j)
v.fixed.set(bw + j, a.fixed.get(j));
if (a.fixed().get(j))
v.set_fixed_bit(bw + j, v.get_bit(bw + j));
bw += a.bw;
}
break;
@ -444,19 +466,18 @@ namespace sls {
VERIFY(bv.is_extract(e, lo, hi, child));
auto& a = ev.wval(child);
for (unsigned i = lo; i <= hi; ++i)
v.fixed.set(i - lo, a.fixed.get(i));
if (a.fixed().get(i))
v.set_fixed_bit(i - lo, v.get_bit(i));
break;
}
case OP_BNEG: {
auto& a = ev.wval(e->get_arg(0));
bool pfixed = true;
for (unsigned i = 0; i < v.bw; ++i) {
if (pfixed && a.fixed.get(i))
v.fixed.set(i, true);
else {
if (pfixed && a.fixed().get(i))
v.set_fixed_bit(i, v.get_bit(i));
else
pfixed = false;
v.fixed.set(i, false);
}
}
break;
}
@ -488,7 +509,7 @@ namespace sls {
case OP_BUREM0:
case OP_BSMOD:
case OP_BSMOD_I:
case OP_BSMOD0:
case OP_BSMOD0:
case OP_BXNOR:
// NOT_IMPLEMENTED_YET();
break;
@ -505,7 +526,7 @@ namespace sls {
case OP_BSMUL_OVFL:
case OP_BUMUL_NO_OVFL:
case OP_BUMUL_OVFL:
case OP_BIT2BOOL:
case OP_BIT2BOOL:
case OP_ULEQ:
case OP_UGEQ:
case OP_UGT:
@ -516,6 +537,6 @@ namespace sls {
case OP_SLT:
UNREACHABLE();
break;
}
}
}
}