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add v0 of equality solver

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This commit is contained in:
Nikolaj Bjorner 2024-11-30 17:25:49 -08:00
parent 05e053247d
commit 24c3cd38d1
4 changed files with 113 additions and 3 deletions
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11
src/ast/seq_decl_plugin.cpp
View file

@ -945,6 +945,17 @@ void seq_util::str::get_concat(expr* e, expr_ref_vector& es) const {
}
}
void seq_util::str::get_concat(expr* e, ptr_vector<expr>& es) const {
expr* e1, * e2;
while (is_concat(e, e1, e2)) {
get_concat(e1, es);
e = e2;
}
if (!is_empty(e)) {
es.push_back(e);
}
}
/*
Returns true if s is an expression of the form (l = |u|) |u|-k or (-k)+|u| or |u|+(-k).
Also returns true and assigns k=0 and l=s if s is |u|.

1
src/ast/seq_decl_plugin.h
View file

@ -424,6 +424,7 @@ public:
MATCH_UNARY(is_unit);
void get_concat(expr* e, expr_ref_vector& es) const;
void get_concat(expr* e, ptr_vector<expr>& es) const;
void get_concat_units(expr* e, expr_ref_vector& es) const;
expr* get_leftmost_concat(expr* e) const { expr* e1, *e2; while (is_concat(e, e1, e2)) e = e1; return e; }
expr* get_rightmost_concat(expr* e) const { expr* e1, *e2; while (is_concat(e, e1, e2)) e = e2; return e; }

100
src/ast/sls/sls_seq_plugin.cpp
View file

@ -224,6 +224,23 @@ namespace sls {
return m_values.get(id, nullptr);
}
ptr_vector<expr> const& seq_plugin::lhs(expr* eq) {
auto& ev = get_eval(eq);
if (ev.lhs.empty()) {
expr* x, * y;
VERIFY(m.is_eq(eq, x, y));
seq.str.get_concat(x, ev.lhs);
seq.str.get_concat(y, ev.rhs);
}
return ev.lhs;
}
ptr_vector<expr> const& seq_plugin::rhs(expr* eq) {
lhs(eq);
auto& e = get_eval(eq);
return e.rhs;
}
zstring& seq_plugin::strval0(expr* e) {
SASSERT(seq.is_string(e->get_sort()));
return get_eval(e).val0.svalue;
@ -557,8 +574,10 @@ namespace sls {
bool is_true = ctx.is_true(e);
expr* x, * y;
VERIFY(m.is_eq(e, x, y));
verbose_stream() << is_true << ": " << mk_bounded_pp(e, m, 3) << "\n";
IF_VERBOSE(3, verbose_stream() << is_true << ": " << mk_bounded_pp(e, m, 3) << "\n");
if (ctx.is_true(e)) {
if (ctx.rand(10) != 0)
return repair_down_str_eq_unify(e);
if (!is_value(x))
m_str_updates.push_back({ x, strval1(y), 1 });
if (!is_value(y))
@ -579,6 +598,81 @@ namespace sls {
return apply_update();
}
bool seq_plugin::repair_down_str_eq_unify(app* eq) {
auto const& L = lhs(eq);
auto const& R = rhs(eq);
unsigned i = 0, j = 0; // position into current string
unsigned ni = 0, nj = 0; // current string in concatenation
double depth = 1.0; // priority of update. Doubled when depth of equal strings are increased.
while (ni < L.size() && nj < R.size()) {
auto const& xi = L[ni];
auto const& yj = R[nj];
auto const& vi = strval0(xi);
auto const& vj = strval0(yj);
IF_VERBOSE(4,
verbose_stream() << "unify: \"" << vi << "\" = \"" << vj << "\" incides " << i << " " << j << "\n";
verbose_stream() << vi.length() << " " << vj.length() << "\n");
if (vi.length() == i && vj.length() == j) {
depth *= 2;
if (nj + 1 < R.size() && !strval0(R[nj + 1]).empty())
m_str_updates.push_back({ xi, vi + zstring(strval0(R[nj + 1])[0]), depth });
if (ni + 1 < L.size() && !strval0(L[ni + 1]).empty())
m_str_updates.push_back({ yj, vj + zstring(strval0(L[ni + 1])[0]), depth });
i = 0;
j = 0;
++ni;
++nj;
continue;
}
if (vi.length() == i) {
// xi -> vi + vj[j]
SASSERT(j < vj.length());
m_str_updates.push_back({ xi, vi + zstring(vj[j]), depth});
depth *= 2;
i = 0;
++ni;
continue;
}
if (vj.length() == j) {
// yj -> vj + vi[i]
SASSERT(i < vi.length());
m_str_updates.push_back({ yj, vj + zstring(vi[i]), depth });
depth *= 2;
j = 0;
++nj;
continue;
}
SASSERT(i < vi.length());
SASSERT(j < vj.length());
if (is_value(xi) && is_value(yj)) {
++i, ++j;
continue;
}
if (vi[i] == vj[j]) {
++i, ++j;
continue;
}
if (!is_value(xi)) {
m_str_updates.push_back({ xi, vi.extract(0, i), depth });
m_str_updates.push_back({ xi, vi.extract(0, i) + zstring(vj[j]), depth});
}
if (!is_value(yj)) {
m_str_updates.push_back({ yj, vj.extract(0, j), depth });
m_str_updates.push_back({ yj, vj.extract(0, j) + zstring(vi[i]), depth });
}
break;
}
for (; ni < L.size(); ++ni)
if (!is_value(L[ni]))
m_str_updates.push_back({ L[ni], zstring(), depth });
for (; nj < R.size(); ++nj)
if (!is_value(R[nj]))
m_str_updates.push_back({ R[nj], zstring(), depth });
return apply_update();
}
bool seq_plugin::repair_down_seq(app* e) {
switch (e->get_decl_kind()) {
case OP_SEQ_CONTAINS:
@ -1021,7 +1115,7 @@ namespace sls {
auto [e, value, score] = m_str_updates[i];
if (update(e, value)) {
verbose_stream() << "set value " << mk_bounded_pp(e, m) << " := \"" << value << "\"\n";
IF_VERBOSE(3, verbose_stream() << "set value " << mk_bounded_pp(e, m) << " := \"" << value << "\"\n");
m_str_updates.reset();
m_int_updates.reset();
return true;
@ -1034,7 +1128,7 @@ namespace sls {
else {
auto [e, value, score] = m_int_updates[i];
verbose_stream() << "set value " << mk_bounded_pp(e, m) << " := " << value << "\n";
IF_VERBOSE(3, verbose_stream() << "set value " << mk_bounded_pp(e, m) << " := " << value << "\n");
if (update(e, value)) {
m_int_updates.reset();

4
src/ast/sls/sls_seq_plugin.h
View file

@ -38,6 +38,7 @@ namespace sls {
bool is_value = false;
unsigned min_length = 0;
unsigned max_length = UINT_MAX;
ptr_vector<expr> lhs, rhs;
};
seq_util seq;
@ -69,6 +70,7 @@ namespace sls {
bool repair_down_seq(app* e);
bool repair_down_eq(app* e);
bool repair_down_str_eq_unify(app* e);
bool repair_down_str_eq(app* e);
bool repair_down_str_extract(app* e);
bool repair_down_str_contains(expr* e);
@ -107,6 +109,8 @@ namespace sls {
eval& get_eval(expr* e);
eval* get_eval(expr* e) const;
ptr_vector<expr> const& lhs(expr* eq);
ptr_vector<expr> const& rhs(expr* eq);
bool is_value(expr* e);
public: