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updates to multiplication

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This commit is contained in:
Nikolaj Bjorner 2024-02-26 08:16:12 -08:00
parent 2590d672f4
commit 8f139e862c
1 changed files with 28 additions and 47 deletions
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75
src/ast/sls/bv_sls_eval.cpp
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@ -989,23 +989,30 @@ namespace bv {
}
//
// first try to set a := e - b
// If this fails, set a to a random value
//
bool sls_eval::try_repair_add(bvval const& e, bvval& a, bvval const& b) {
a.set_sub(m_tmp, e.bits(), b.bits());
return a.set_repair(random_bool(), m_tmp);
if (a.try_set(m_tmp))
return true;
a.get_variant(m_tmp, m_rand);
return a.set_repair(random_bool(), m_tmp);
}
bool sls_eval::try_repair_sub(bvval const& e, bvval& a, bvval & b, unsigned i) {
if (i == 0) {
if (i == 0)
// e = a - b -> a := e + b
a.set_add(m_tmp, e.bits(), b.bits());
return a.set_repair(random_bool(), m_tmp);
}
else {
a.set_add(m_tmp, e.bits(), b.bits());
else
// b := a - e
b.set_sub(m_tmp, a.bits(), e.bits());
return b.set_repair(random_bool(), m_tmp);
}
b.set_sub(m_tmp, a.bits(), e.bits());
if (a.try_set(m_tmp))
return true;
// fall back to a random value
a.get_variant(m_tmp, m_rand);
return a.set_repair(random_bool(), m_tmp);
}
/**
@ -1013,19 +1020,15 @@ namespace bv {
* 8*e = a*(2b), then a = 4e*b^-1
*/
bool sls_eval::try_repair_mul(bvval const& e, bvval& a, bvval const& b) {
if (b.is_zero()) {
if (a.is_zero()) {
a.set(m_tmp, 1);
return a.try_set(m_tmp);
}
verbose_stream() << "cannot repair 0\n";
return false;
}
unsigned parity_e = e.parity(e.bits());
unsigned parity_b = b.parity(b.bits());
#if 1
if (e.is_zero()) {
a.get_variant(m_tmp, m_rand);
for (unsigned i = 0; i < e.bw - parity_b; ++i)
m_tmp.set(i, false);
return a.set_repair(random_bool(), m_tmp);
}
auto& x = m_tmp;
auto& y = m_tmp2;
@ -1041,8 +1044,11 @@ namespace bv {
// x*ta + y*tb = x
b.get(y);
if (parity_b > 0)
if (parity_b > 0) {
b.shift_right(y, parity_b);
for (unsigned i = parity_b; i < e.bw; ++i)
y.set(i, m_rand() % 2 == 0);
}
y[a.nw] = 0;
x[a.nw] = 0;
@ -1084,38 +1090,13 @@ namespace bv {
if (parity_b > 0)
b.shift_right(y, parity_b);
a.set_mul(m_tmp, tb, y);
#if 0
for (unsigned i = a.nw; i-- > 0; )
verbose_stream() << tb[i];
verbose_stream() << "\n";
for (unsigned i = a.nw; i-- > 0; )
verbose_stream() << y[i];
verbose_stream() << "\n";
for (unsigned i = a.nw; i-- > 0; )
verbose_stream() << m_tmp[i];
verbose_stream() << "\n";
#endif
SASSERT(a.is_one(m_tmp));
#endif
e.get(m_tmp2);
if (parity_e > 0 && parity_b > 0)
b.shift_right(m_tmp2, std::min(parity_b, parity_e));
a.set_mul(m_tmp, tb, m_tmp2);
return a.set_repair(random_bool(), m_tmp);
#else
rational ne, nb;
e.get_value(e.bits, ne);
b.get_value(b.bits, nb);
if (parity_b > 0)
ne /= rational::power_of_two(std::min(parity_b, parity_e));
auto inv_b = nb.pseudo_inverse(b.bw);
rational na = mod(inv_b * ne, rational::power_of_two(a.bw));
a.set_value(m_tmp, na);
return a.set_repair(random_bool(), m_tmp);
#endif
return a.set_repair(random_bool(), m_tmp);
}
bool sls_eval::try_repair_bnot(bvval const& e, bvval& a) {