mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-05-05 23:05:46 +00:00
Code Activity

smul no overflow

Browse source 
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
Download patch file Download diff file Expand all files Collapse all files

79
src/math/polysat/smul_ovfl_constraint.cpp Normal file
View file

@ -0,0 +1,79 @@
/*++
Copyright (c) 2021 Microsoft Corporation
Module Name:
polysat multiplication overflow constraint
Author:
Jakob Rath, Nikolaj Bjorner (nbjorner) 2021-12-09
--*/
#include "math/polysat/smul_ovfl_constraint.h"
#include "math/polysat/solver.h"
namespace polysat {
smul_ovfl_constraint::smul_ovfl_constraint(constraint_manager& m, pdd const& p, pdd const& q):
constraint(m, ckind_t::smul_ovfl_t), m_p(p), m_q(q) {
simplify();
m_vars.append(m_p.free_vars());
for (auto v : m_q.free_vars())
if (!m_vars.contains(v))
m_vars.push_back(v);
}
void smul_ovfl_constraint::simplify() {
if (m_p.is_zero() || m_q.is_zero() ||
m_p.is_one() || m_q.is_one()) {
m_q = 0;
m_p = 0;
return;
}
if (m_p.index() > m_q.index())
std::swap(m_p, m_q);
}
std::ostream& smul_ovfl_constraint::display(std::ostream& out, lbool status) const {
switch (status) {
case l_true: return display(out);
case l_false: return display(out << "~");
case l_undef: return display(out << "?");
}
return out;
}
std::ostream& smul_ovfl_constraint::display(std::ostream& out) const {
return out << "sovfl*(" << m_p << ", " << m_q << ")";
}
void smul_ovfl_constraint::narrow(solver& s, bool is_positive, bool first) {
if (!first)
return;
signed_constraint sc(this, is_positive);
if (is_positive) {
s.add_clause(~sc, s.ule(2, p()), false);
s.add_clause(~sc, s.ule(2, q()), false);
s.add_clause(~sc, ~s.sgt(p(), 0), s.sgt(q(), 0), false);
s.add_clause(~sc, ~s.sgt(q(), 0), s.sgt(p(), 0), false);
s.add_clause(~sc, ~s.sgt(p(), 0), s.slt(p()*q(), 0), s.mul_ovfl(p(), q()), false);
s.add_clause(~sc, s.sgt(p(), 0), s.slt(p()*q(), 0), s.mul_ovfl(-p(), -q()), false);
}
else {
// smul_noovfl(p,q) => sign(p) != sign(q) or p'*q' < 2^{K-1}
s.add_clause(~sc, ~s.sgt(p(), 0), ~s.sgt(q(), 0), ~s.mul_ovfl(p(), q()), false);
s.add_clause(~sc, ~s.sgt(p(), 0), ~s.sgt(q(), 0), ~s.slt(p()*q(), 0), false);
s.add_clause(~sc, ~s.slt(p(), 0), ~s.slt(q(), 0), ~s.mul_ovfl(-p(), -q()), false);
s.add_clause(~sc, ~s.slt(p(), 0), ~s.slt(q(), 0), ~s.slt((-p())*(-q()), 0), false);
}
}
unsigned smul_ovfl_constraint::hash() const {
return mk_mix(p().hash(), q().hash(), kind());
}
bool smul_ovfl_constraint::operator==(constraint const& other) const {
return other.is_smul_ovfl() && p() == other.to_smul_ovfl().p() && q() == other.to_smul_ovfl().q();
}
}