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smul no overflow

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-02-16 18:55:07 +02:00
parent 89d6f1c191
commit 8c9835bca6
24 changed files with 376 additions and 63 deletions
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119
src/math/polysat/forbidden_intervals.cpp
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@ -17,6 +17,7 @@ Author:
#include "math/polysat/interval.h"
#include "math/polysat/solver.h"
#include "math/polysat/log.h"
#include "math/polysat/mul_ovfl_constraint.h"
namespace polysat {
@ -28,20 +29,112 @@ namespace polysat {
* \returns True iff a forbidden interval exists and the output parameters were set.
*/
bool forbidden_intervals::get_interval(signed_constraint const& c, pvar v, fi_record& fi) {
if (!c->is_ule())
return false;
struct backtrack {
bool released = false;
vector<signed_constraint>& side_cond;
unsigned sz;
backtrack(vector<signed_constraint>& s):side_cond(s), sz(s.size()) {}
~backtrack() {
if (!released)
side_cond.shrink(sz);
}
};
if (c->is_ule())
return get_interval_ule(c, v, fi);
if (c->is_mul_ovfl())
return get_interval_mul_ovfl(c, v, fi);
return false;
}
bool forbidden_intervals::get_interval_mul_ovfl(signed_constraint const& c, pvar v, fi_record& fi) {
std::cout << "FORBIDDEN v" << v << "\n";
backtrack _backtrack(fi.side_cond);
fi.coeff = 1;
fi.src = c;
// eval(lhs) = a1*v + eval(e1) = a1*v + b1
// eval(rhs) = a2*v + eval(e2) = a2*v + b2
// We keep the e1, e2 around in case we need side conditions such as e1=b1, e2=b2.
auto [ok1, a1, e1, b1] = linear_decompose(v, c->to_mul_ovfl().p(), fi.side_cond);
auto [ok2, a2, e2, b2] = linear_decompose(v, c->to_mul_ovfl().q(), fi.side_cond);
auto& m = e1.manager();
rational bound = m.max_value();
if (ok2 && !ok1) {
std::swap(a1, a2);
std::swap(e1, e2);
std::swap(b1, b2);
std::swap(ok1, ok2);
}
if (ok1 && !ok2 && a1.is_one() && b1.is_zero()) {
if (c.is_positive()) {
_backtrack.released = true;
rational lo_val(0);
rational hi_val(2);
pdd lo = m.mk_val(lo_val);
pdd hi = m.mk_val(hi_val);
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
return true;
}
}
if (!ok1 || !ok2)
return false;
if (a2.is_one() && a1.is_zero()) {
std::swap(a1, a2);
std::swap(e1, e2);
std::swap(b1, b2);
}
if (!a1.is_one() || !a2.is_zero())
return false;
if (!b1.is_zero())
return false;
_backtrack.released = true;
// Ovfl(v, e2)
if (c.is_positive()) {
if (b2.val() <= 1) {
fi.interval = eval_interval::full();
fi.side_cond.push_back(s.ule(e2, 1));
}
else {
// [0, div(bound, b2.val()) + 1[
rational lo_val(0);
rational hi_val(div(bound, b2.val()) + 1);
pdd lo = m.mk_val(lo_val);
pdd hi = m.mk_val(hi_val);
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
fi.side_cond.push_back(s.ule(e2, b2.val()));
}
}
else {
if (b2.val() <= 1) {
_backtrack.released = false;
return false;
}
else {
// [div(bound, b2.val()) + 1, 0[
rational lo_val(div(bound, b2.val()) + 1);
rational hi_val(0);
pdd lo = m.mk_val(lo_val);
pdd hi = m.mk_val(hi_val);
fi.interval = eval_interval::proper(lo, lo_val, hi, hi_val);
fi.side_cond.push_back(s.ule(b2.val(), e2));
}
}
LOG("overflow interval " << fi.interval);
return true;
}
bool forbidden_intervals::get_interval_ule(signed_constraint const& c, pvar v, fi_record& fi) {
backtrack _backtrack(fi.side_cond);
fi.coeff = 1;