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Forward propagation for op_constraints + optimization for left/right shift

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This commit is contained in:
Clemens Eisenhofer 2023-01-11 10:29:26 +01:00
parent 1d0ad1ccc0
commit 2581754c3e
4 changed files with 89 additions and 45 deletions
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33
src/math/polysat/constraint_manager.cpp
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@ -453,6 +453,16 @@ namespace polysat {
return -p - 1;
}
static unsigned min_coefficient_power_of_2(const pdd& p) {
if (p.is_zero())
return 0; // TODO: Or something different?
unsigned min_power = UINT32_MAX;
for (auto& m : p)
min_power = std::min(min_power, m.coeff.trailing_zeros());
return min_power;
}
pdd constraint_manager::mk_op_term(op_constraint::code op, pdd const& p, pdd const& q) {
auto& m = p.manager();
unsigned sz = m.power_of_2();
@ -470,23 +480,34 @@ namespace polysat {
}
pdd constraint_manager::lshr(pdd const& p, pdd const& q) {
if (p.is_val() && q.is_val() && q.val().is_unsigned()) {
return p.manager().mk_val(div(p.val(), rational::power_of_two(q.val().get_unsigned())));
if (q.is_val()) {
if (!q.val().is_unsigned())
return p.manager().zero(); // TODO: The number is huge. We will for sure shift out all bits
if (p.is_val())
return p.manager().mk_val(div(p.val(), rational::power_of_two(q.val().get_unsigned())));
unsigned common = min_coefficient_power_of_2(p);
pdd div = p.manager().zero();
for (auto& m : p)
div += machine_div(m.coeff, rational::power_of_two(common));
return div;
}
return mk_op_term(op_constraint::code::lshr_op, p, q);
}
pdd constraint_manager::shl(pdd const& p, pdd const& q) {
if (p.is_val() && q.is_val() && q.val().is_unsigned()) {
return p.manager().mk_val(p.val() * rational::power_of_two(q.val().get_unsigned()));
if (q.is_val()) {
if (!q.val().is_unsigned())
return p.manager().zero();
return p * rational::power_of_two(q.val().get_unsigned());
}
return mk_op_term(op_constraint::code::shl_op, p, q);
}
pdd constraint_manager::band(pdd const& p, pdd const& q) {
if (p.is_val() && q.is_val()) {
if (p.is_val() && q.is_val())
return p.manager().mk_val(bitwise_and(p.val(), q.val()));
}
return mk_op_term(op_constraint::code::and_op, p, q);
}