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Phase saving and some minor changes (#5209)

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* Implement phase saving

* Implement signed comparison on BDD vectors

* Add fdd::non_zero

* Simplify construction of fdds over disjoint variables

* Minor changes to adding constraint
This commit is contained in:
Jakob Rath 2021-04-22 18:47:46 +02:00 • committed by GitHub
parent 09f31ebb0a
commit 12444c7e8b
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 156 additions and 31 deletions
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27
src/math/dd/dd_bdd.cpp
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@ -937,6 +937,26 @@ namespace dd {
bdd bdd_manager::mk_ult(bddv const& a, bddv const& b) { return mk_ule(a, b) && !mk_eq(a, b); }
bdd bdd_manager::mk_ugt(bddv const& a, bddv const& b) { return mk_ult(b, a); }
bdd bdd_manager::mk_sle(bddv const& a, bddv const& b) {
SASSERT(a.size() == b.size());
// Note: sle can be reduced to ule by flipping the sign bits of both arguments
bdd lt = mk_false();
bdd eq = mk_true();
unsigned const sz = a.size();
if (sz > 0) {
lt = a[sz - 1] && !b[sz - 1];
eq = !(a[sz - 1] ^ b[sz - 1]);
for (unsigned i = sz - 1; i-- > 0; ) {
lt |= eq && (!a[i] && b[i]);
eq &= !(a[i] ^ b[i]);
}
}
return lt || eq;
}
bdd bdd_manager::mk_sge(bddv const& a, bddv const& b) { return mk_sle(b, a); }
bdd bdd_manager::mk_slt(bddv const& a, bddv const& b) { return mk_sle(a, b) && !mk_eq(a, b); }
bdd bdd_manager::mk_sgt(bddv const& a, bddv const& b) { return mk_slt(b, a); }
bddv bdd_manager::mk_add(bddv const& a, bddv const& b) {
SASSERT(a.size() == b.size());
bdd carry = mk_false();
@ -1098,13 +1118,6 @@ namespace dd {
return result;
}
#if 0
bdd bdd_manager::mk_sle(bddv const& a, bddv const& b);
bdd bdd_manager::mk_sge(bddv const& a, bddv const& b) { return mk_sle(b, a); }
bdd bdd_manager::mk_slt(bddv const& a, bddv const& b) { return mk_sle(a, b) && !mk_eq(a, b); }
bdd bdd_manager::mk_sgt(bddv const& a, bddv const& b) { return mk_slt(b, a); }
#endif
void bddv::shl() {
for (unsigned j = size(); j-- > 1;)
m_bits[j] = m_bits[j - 1];