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add another baseline heuristic for string equalities, add cases for array axioms.

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2024-12-09 15:55:11 -08:00
parent e5f8327483
commit 8f5658b77d
6 changed files with 340 additions and 29 deletions
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104
src/ast/sls/sls_array_plugin.cpp
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@ -35,7 +35,7 @@ namespace sls {
m_g = alloc(euf::egraph, m);
m_kv = nullptr;
init_egraph(*m_g);
saturate_store(*m_g);
saturate(*m_g);
return true;
}
@ -43,28 +43,73 @@ namespace sls {
// ensure b[i] ~ v
// ensure b[j] ~ a[j] for j != i
void array_plugin::saturate_store(euf::egraph& g) {
void array_plugin::saturate(euf::egraph& g) {
unsigned sz = 0;
while (sz < g.nodes().size()) {
sz = g.nodes().size();
for (unsigned i = 0; i < sz; ++i) {
auto n = g.nodes()[i];
if (!a.is_store(n->get_expr()))
continue;
force_store_axiom1(g, n);
for (auto p : euf::enode_parents(n->get_root()))
if (a.is_select(p->get_expr()))
force_store_axiom2_down(g, n, p);
if (a.is_store(n->get_expr()))
saturate_store(g, n);
else if (a.is_const(n->get_expr()))
saturate_const(g, n);
else if (a.is_map(n->get_expr()))
saturate_map(g, n);
auto arr = n->get_arg(0);
for (auto p : euf::enode_parents(arr->get_root()))
if (a.is_select(p->get_expr()))
force_store_axiom2_up(g, n, p);
}
}
display(verbose_stream() << "saturated\n");
IF_VERBOSE(2, display(verbose_stream() << "saturated\n"));
}
void array_plugin::saturate_store(euf::egraph& g, euf::enode* n) {
force_store_axiom1(g, n);
for (auto p : euf::enode_parents(n->get_root()))
if (a.is_select(p->get_expr()))
force_store_axiom2_down(g, n, p);
auto arr = n->get_arg(0);
for (auto p : euf::enode_parents(arr->get_root()))
if (a.is_select(p->get_expr()))
force_store_axiom2_up(g, n, p);
}
void array_plugin::saturate_const(euf::egraph& g, euf::enode* n) {
for (auto p : euf::enode_parents(n->get_root()))
if (a.is_select(p->get_expr()))
force_const_axiom(g, n, p);
}
void array_plugin::saturate_map(euf::egraph& g, euf::enode* n) {
for (auto p : euf::enode_parents(n->get_root()))
if (a.is_select(p->get_expr()))
add_map_axiom(g, n, p);
}
void array_plugin::add_map_axiom(euf::egraph& g, euf::enode * n, euf::enode* sel) {
func_decl* f = nullptr;
VERIFY(sel->get_arg(0)->get_root() == n->get_root());
SASSERT(a.is_map(n->get_expr()));
VERIFY(a.is_map(n->get_decl(), f));
expr_ref apply_map(m);
expr_ref_vector args(m);
euf::enode_vector eargs;
for (auto arg : euf::enode_args(n)) {
auto nsel = mk_select(g, arg, sel);
eargs.push_back(nsel);
args.push_back(nsel->get_expr());
}
expr_ref f_map(m.mk_app(f, args), m);
auto nsel = mk_select(g, n, sel);
auto nmap = g.find(f_map);
if (!nmap)
nmap = g.mk(f_map, 0, eargs.size(), eargs.data());
if (are_distinct(nsel, nmap)) {
expr_ref eq(m.mk_eq(nmap->get_expr(), nsel->get_expr()), m);
ctx.add_clause(eq);
}
else {
g.merge(nmap, nsel, nullptr);
VERIFY(g.propagate());
}
}
euf::enode* array_plugin::mk_select(euf::egraph& g, euf::enode* b, euf::enode* sel) {
@ -130,6 +175,24 @@ namespace sls {
}
}
// const(v) ~ b, b[j] occurs -> v = (const v)[j]
void array_plugin::force_const_axiom(euf::egraph& g, euf::enode* cn, euf::enode* sel) {
SASSERT(a.is_const(cn->get_expr()));
SASSERT(a.is_select(sel->get_expr()));
if (sel->get_arg(0)->get_root() != cn->get_root())
return;
auto val = cn->get_arg(0);
auto nsel = mk_select(g, cn, sel);
if (are_distinct(nsel, sel)) {
expr_ref eq(m.mk_eq(val->get_expr(), nsel->get_expr()), m);
ctx.add_clause(eq);
}
else {
g.merge(nsel, sel, nullptr);
VERIFY(g.propagate());
}
}
bool array_plugin::are_distinct(euf::enode* a, euf::enode* b) {
a = a->get_root();
b = b->get_root();
@ -156,7 +219,7 @@ namespace sls {
args.push_back(sto->get_arg(i));
expr_ref sel(a.mk_select(args), m);
expr_ref eq(m.mk_eq(sel, to_app(sto)->get_arg(sto->get_num_args() - 1)), m);
verbose_stream() << "add store axiom 1 " << mk_bounded_pp(sto, m) << "\n";
IF_VERBOSE(3, verbose_stream() << "add store axiom 1 " << mk_bounded_pp(sto, m) << "\n");
ctx.add_clause(eq);
}
@ -177,7 +240,7 @@ namespace sls {
ors.push_back(eq);
for (unsigned i = 1; i < sel->get_num_args() - 1; ++i)
ors.push_back(m.mk_eq(sel->get_arg(i), sto->get_arg(i)));
verbose_stream() << "add store axiom 2 " << mk_bounded_pp(sto, m) << " " << mk_bounded_pp(sel, m) << "\n";
IF_VERBOSE(3, verbose_stream() << "add store axiom 2 " << mk_bounded_pp(sto, m) << " " << mk_bounded_pp(sel, m) << "\n");
ctx.add_clause(m.mk_or(ors));
}
@ -195,7 +258,7 @@ namespace sls {
if (a.is_array(t))
continue;
auto v = ctx.get_value(t);
verbose_stream() << "init " << mk_bounded_pp(t, m) << " := " << mk_bounded_pp(v, m) << "\n";
IF_VERBOSE(3, verbose_stream() << "init " << mk_bounded_pp(t, m) << " := " << mk_bounded_pp(v, m) << "\n");
n2 = g.find(v);
n2 = n2 ? n2: g.mk(v, 0, 0, nullptr);
g.merge(n1, n2, nullptr);
@ -209,7 +272,7 @@ namespace sls {
g.merge(g.find(x), g.find(y), nullptr);
}
display(verbose_stream());
IF_VERBOSE(3, display(verbose_stream()));
}
@ -236,12 +299,13 @@ namespace sls {
m_g = alloc(euf::egraph, m);
init_egraph(*m_g);
flet<bool> _strong(m_add_conflicts, false);
saturate_store(*m_g);
saturate(*m_g);
}
if (!m_kv) {
m_kv = alloc(kv);
init_kv(*m_g, *m_kv);
}
// TODO: adapt to handle "const" arrays and multi-dimensional arrays.
auto& kv = *m_kv;
auto n = m_g->find(e)->get_root();
expr_ref r(n->get_expr(), m);