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Nikolaj Bjorner 2021-03-06 12:36:14 -08:00
parent 8de96009cd
commit 7edc99f807
1 changed files with 128 additions and 118 deletions
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246
src/smt/seq_eq_solver.cpp
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@ -126,6 +126,8 @@ expr* theory_seq::expr2rep(expr* e) {
}
#if 0
/**
\brief
@ -158,7 +160,6 @@ expr* theory_seq::expr2rep(expr* e) {
TODO: propagate length offsets for last vars
*/
#if 0
bool theory_seq::find_better_rep(expr_ref_vector const& ls, expr_ref_vector const& rs, unsigned idx,
dependency*& deps, expr_ref_vector & res) {
@ -235,6 +236,32 @@ bool theory_seq::find_better_rep(expr_ref_vector const& ls, expr_ref_vector cons
}
return false;
}
int theory_seq::find_fst_non_empty_idx(expr_ref_vector const& xs) {
for (unsigned i = 0; i < xs.size(); ++i) {
expr* x = xs[i];
if (!is_var(x))
return -1;
expr_ref e = mk_len(x);
if (ctx.e_internalized(e)) {
enode* root = ctx.get_enode(e)->get_root();
rational val;
if (m_autil.is_numeral(root->get_expr(), val) && val.is_zero()) {
continue;
}
}
return i;
}
return -1;
}
expr* theory_seq::find_fst_non_empty_var(expr_ref_vector const& x) {
int i = find_fst_non_empty_idx(x);
if (i >= 0)
return x[i];
return nullptr;
}
#endif
bool theory_seq::has_len_offset(expr_ref_vector const& ls, expr_ref_vector const& rs, int & offset) {
@ -399,20 +426,17 @@ bool theory_seq::branch_variable_mb() {
rational l1, l2;
for (const auto& elem : len1) l1 += elem;
for (const auto& elem : len2) l2 += elem;
if (l1 != l2) {
expr_ref l = mk_concat(e.ls);
expr_ref r = mk_concat(e.rs);
expr_ref lnl = mk_len(l), lnr = mk_len(r);
if (propagate_eq(e.dep(), lnl, lnr, false)) {
change = true;
}
continue;
}
if (split_lengths(e.dep(), e.ls, e.rs, len1, len2)) {
if (l1 == l2 && split_lengths(e.dep(), e.ls, e.rs, len1, len2)) {
TRACE("seq", tout << "split lengths\n";);
change = true;
break;
}
expr_ref l = mk_concat(e.ls);
expr_ref r = mk_concat(e.rs);
expr_ref lnl = mk_len(l), lnr = mk_len(r);
if (propagate_eq(e.dep(), lnl, lnr, false))
change = true;
}
return change;
}
@ -601,6 +625,14 @@ bool theory_seq::branch_binary_variable(depeq const& e) {
bool theory_seq::branch_unit_variable() {
bool result = false;
for (auto const& e : m_eqs) {
#if 0
eqr er(e.ls, e.rs);
m_eq_deps = e.deps;
if (m_eq.branch(0, er)) {
result = true;
break;
}
#else
if (is_unit_eq(e.ls, e.rs) &&
branch_unit_variable(e.dep(), e.ls[0], e.rs)) {
result = true;
@ -611,6 +643,7 @@ bool theory_seq::branch_unit_variable() {
result = true;
break;
}
#endif
}
CTRACE("seq", result, tout << "branch unit variable\n";);
return result;
@ -842,121 +875,98 @@ bool theory_seq::branch_quat_variable(depeq const& e) {
else if (!can_align_from_lhs(xs, ys) && !can_align_from_rhs(xs, ys))
cond = true;
if (cond) {
literal_vector lits;
if (xs == ys) {
literal lit = mk_eq(mk_len(x1), mk_len(y1), false);
if (ctx.get_assignment(lit) == l_undef) {
TRACE("seq", tout << mk_pp(x1, m) << " = " << mk_pp(y1, m) << "?\n";);
ctx.mark_as_relevant(lit);
return true;
}
else if (ctx.get_assignment(lit) == l_true) {
TRACE("seq", tout << mk_pp(x1, m) << " = " << mk_pp(y1, m) << "\n";);
propagate_eq(dep, lit, x1, y1, true);
propagate_eq(dep, lit, x2, y2, true);
return true;
}
TRACE("seq", tout << mk_pp(x1, m) << " != " << mk_pp(y1, m) << "\n";);
lits.push_back(~lit);
}
literal lit1 = mk_alignment(x1, y1);
literal lit2 = m_ax.mk_ge(mk_sub(mk_len(y1), mk_len(x1)), xs.size());
literal lit3 = m_ax.mk_ge(mk_sub(mk_len(x1), mk_len(y1)), ys.size());
if (ctx.get_assignment(lit1) == l_undef) {
TRACE("seq", tout << mk_pp(x1, m) << " <= " << mk_pp(y1, m) << "?\n";);
ctx.mark_as_relevant(lit1);
if (!cond)
return false;
literal_vector lits;
if (xs == ys) {
literal lit = mk_eq(mk_len(x1), mk_len(y1), false);
if (ctx.get_assignment(lit) == l_undef) {
TRACE("seq", tout << mk_pp(x1, m) << " = " << mk_pp(y1, m) << "?\n";);
ctx.mark_as_relevant(lit);
return true;
}
if (ctx.get_assignment(lit1) == l_true) {
TRACE("seq", tout << mk_pp(x1, m) << " <= " << mk_pp(y1, m) << "\n";);
if (ctx.get_assignment(lit2) == l_undef) {
ctx.mark_as_relevant(lit2);
return true;
}
}
else {
TRACE("seq", tout << mk_pp(x1, m) << " > " << mk_pp(y1, m) << "\n";);
if (ctx.get_assignment(lit3) == l_undef) {
ctx.mark_as_relevant(lit3);
return true;
}
}
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref x1xs = mk_concat(x1, xsE);
expr_ref y1ys = mk_concat(y1, ysE);
expr_ref xsx2 = mk_concat(xsE, x2);
expr_ref ysy2 = mk_concat(ysE, y2);
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit2) == l_true) {
// |x1++xs| <= |y1| => x1 ++ xs ++ z2 = y1, x2 = z2 ++ ys ++ y2
expr_ref Z2 = m_sk.mk_align_m(y1, x1, xsE, x2);
expr_ref x1xsZ2 = mk_concat(x1xs, Z2);
expr_ref Z2ysy2 = mk_concat(Z2, ysy2);
propagate_eq(dep, lit2, x1xsZ2, y1, true);
propagate_eq(dep, lit2, x2, Z2ysy2, true);
else if (ctx.get_assignment(lit) == l_true) {
TRACE("seq", tout << mk_pp(x1, m) << " = " << mk_pp(y1, m) << "\n";);
propagate_eq(dep, lit, x1, y1, true);
propagate_eq(dep, lit, x2, y2, true);
return true;
}
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit3) == l_true) {
// |x1| >= |y1++ys| => x1 = y1 ++ ys ++ z1, z1 ++ xs ++ x2 = y2
expr_ref Z1 = m_sk.mk_align_m(x1, y1, ysE, y2);
expr_ref y1ysZ1 = mk_concat(y1ys, Z1);
expr_ref Z1xsx2 = mk_concat(Z1, xsx2);
propagate_eq(dep, lit3, x1, y1ysZ1, true);
propagate_eq(dep, lit3, Z1xsx2, y2, true);
return true;
}
// Infeasible cases because xs and ys cannot align
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit2) == l_true) {
lits.push_back(~lit1);
lits.push_back(lit2);
return propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit3) == l_true) {
lits.push_back(lit1);
lits.push_back(lit3);
return propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit2) == l_false) {
lits.push_back(lit1);
lits.push_back(~lit2);
return propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit3) == l_false) {
lits.push_back(~lit1);
lits.push_back(~lit3);
return propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
}
UNREACHABLE();
TRACE("seq", tout << mk_pp(x1, m) << " != " << mk_pp(y1, m) << "\n";);
lits.push_back(~lit);
}
return false;
}
int theory_seq::find_fst_non_empty_idx(expr_ref_vector const& xs) {
for (unsigned i = 0; i < xs.size(); ++i) {
expr* x = xs[i];
if (!is_var(x)) return -1;
expr_ref e = mk_len(x);
if (ctx.e_internalized(e)) {
enode* root = ctx.get_enode(e)->get_root();
rational val;
if (m_autil.is_numeral(root->get_expr(), val) && val.is_zero()) {
continue;
}
}
return i;
literal lit1 = mk_alignment(x1, y1);
literal lit2 = m_ax.mk_ge(mk_sub(mk_len(y1), mk_len(x1)), xs.size());
literal lit3 = m_ax.mk_ge(mk_sub(mk_len(x1), mk_len(y1)), ys.size());
if (ctx.get_assignment(lit1) == l_undef) {
TRACE("seq", tout << mk_pp(x1, m) << " <= " << mk_pp(y1, m) << "?\n";);
ctx.mark_as_relevant(lit1);
return true;
}
return -1;
if (ctx.get_assignment(lit1) == l_true) {
TRACE("seq", tout << mk_pp(x1, m) << " <= " << mk_pp(y1, m) << "\n";);
if (ctx.get_assignment(lit2) == l_undef) {
ctx.mark_as_relevant(lit2);
return true;
}
}
else {
TRACE("seq", tout << mk_pp(x1, m) << " > " << mk_pp(y1, m) << "\n";);
if (ctx.get_assignment(lit3) == l_undef) {
ctx.mark_as_relevant(lit3);
return true;
}
}
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref x1xs = mk_concat(x1, xsE);
expr_ref y1ys = mk_concat(y1, ysE);
expr_ref xsx2 = mk_concat(xsE, x2);
expr_ref ysy2 = mk_concat(ysE, y2);
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit2) == l_true) {
// |x1++xs| <= |y1| => x1 ++ xs ++ z2 = y1, x2 = z2 ++ ys ++ y2
expr_ref Z2 = m_sk.mk_align_m(y1, x1, xsE, x2);
expr_ref x1xsZ2 = mk_concat(x1xs, Z2);
expr_ref Z2ysy2 = mk_concat(Z2, ysy2);
propagate_eq(dep, lit2, x1xsZ2, y1, true);
propagate_eq(dep, lit2, x2, Z2ysy2, true);
return true;
}
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit3) == l_true) {
// |x1| >= |y1++ys| => x1 = y1 ++ ys ++ z1, z1 ++ xs ++ x2 = y2
expr_ref Z1 = m_sk.mk_align_m(x1, y1, ysE, y2);
expr_ref y1ysZ1 = mk_concat(y1ys, Z1);
expr_ref Z1xsx2 = mk_concat(Z1, xsx2);
propagate_eq(dep, lit3, x1, y1ysZ1, true);
propagate_eq(dep, lit3, Z1xsx2, y2, true);
return true;
}
// Infeasible cases because xs and ys cannot align
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit2) == l_true) {
lits.push_back(~lit1);
lits.push_back(lit2);
return propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit3) == l_true) {
lits.push_back(lit1);
lits.push_back(lit3);
return propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit2) == l_false) {
lits.push_back(lit1);
lits.push_back(~lit2);
return propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
}
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit3) == l_false) {
lits.push_back(~lit1);
lits.push_back(~lit3);
return propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
}
UNREACHABLE();
}
expr* theory_seq::find_fst_non_empty_var(expr_ref_vector const& x) {
int i = find_fst_non_empty_idx(x);
if (i >= 0)
return x[i];
return nullptr;
}
bool theory_seq::branch_variable_eq() {
unsigned sz = m_eqs.size();