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fix branch_variable() (#4472)

Browse source 
* fixed branch_variable()

* add docs
This commit is contained in:
trinhmt 2020-05-29 01:21:50 +08:00 committed by GitHub
parent e9eec5349d
commit 4aa1e60daa
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GPG key ID: 4AEE18F83AFDEB23
6 changed files with 284 additions and 305 deletions
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2
src/smt/params/theory_seq_params.h
View file

@ -30,7 +30,7 @@ struct theory_seq_params {
theory_seq_params(params_ref const & p = params_ref()):
m_split_w_len(true),
m_split_w_len(false),
m_seq_validate(false),
m_seq_use_derivatives(false),
m_seq_use_unicode(false)

540
src/smt/seq_eq_solver.cpp
View file

@ -458,11 +458,22 @@ bool theory_seq::len_based_split(eq const& e) {
this performs much better on #1628
*/
bool theory_seq::branch_variable() {
if (branch_variable_mb()) return true;
if (branch_variable_eq()) return true;
if (branch_ternary_variable1()) return true;
if (branch_ternary_variable2()) return true;
if (branch_quat_variable()) return true;
if (branch_ternary_variable()) {
TRACE("seq", tout << "branch_ternary_variable\n";);
return true;
}
if (branch_quat_variable()) {
TRACE("seq", tout << "branch_quat_variable\n";);
return true;
}
if (branch_variable_mb()) {
TRACE("seq", tout << "branch_variable_mb\n";);
return true;
}
if (branch_variable_eq()) {
TRACE("seq", tout << "branch_variable_eq\n";);
return true;
}
return false;
}
@ -737,146 +748,109 @@ void theory_seq::branch_unit_variable(dependency* dep, expr* X, expr_ref_vector
}
}
bool theory_seq::branch_ternary_variable1() {
int start = ctx.get_random_value();
for (unsigned i = 0; i < m_eqs.size(); ++i) {
if (branch_ternary_variable(m_eqs[(i + start) % m_eqs.size()]))
return true;
if (branch_ternary_variable2(m_eqs[(i + start) % m_eqs.size()]))
return true;
}
return false;
}
bool theory_seq::branch_ternary_variable2() {
int start = ctx.get_random_value();
for (unsigned i = 0; i < m_eqs.size(); ++i) {
eq const& e = m_eqs[(i + start) % m_eqs.size()];
if (branch_ternary_variable(e, true)) {
bool theory_seq::branch_ternary_variable() {
for (auto const& e : m_eqs) {
if (branch_ternary_variable_rhs(e) || branch_ternary_variable_lhs(e)) {
return true;
}
}
return false;
}
bool theory_seq::eq_unit(expr* l, expr* r) const {
return l == r || is_unit_nth(l) || is_unit_nth(r);
}
// exists x, y, rs' != empty s.t. (ls = x ++ rs' ++ y & rs = rs') || (ls = rs' ++ x && rs = y ++ rs')
// TBD: spec comment above doesn't seem to match what this function does.
unsigned_vector theory_seq::overlap(expr_ref_vector const& ls, expr_ref_vector const& rs) {
// exists x, y, rs' != empty s.t. (ls = x ++ rs ++ y) || (ls = rs' ++ y && rs = x ++ rs')
bool theory_seq::can_align_from_lhs(expr_ref_vector const& ls, expr_ref_vector const& rs) {
SASSERT(!ls.empty() && !rs.empty());
unsigned_vector result;
expr_ref l = mk_concat(ls);
expr_ref r = mk_concat(rs);
expr_ref pair(m.mk_eq(l,r), m);
if (m_overlap.find(pair, result)) {
bool result;
if (m_overlap_lhs.find(pair, result)) {
return result;
}
result.reset();
for (unsigned i = 0; i < ls.size(); ++i) {
if (eq_unit(ls[i], rs.back())) {
bool same = rs.size() > i;
for (unsigned j = 0; same && j < i; ++j) {
same = eq_unit(ls[j], rs[rs.size() - 1 - i + j]);
bool same = true;
// ls = rs' ++ y && rs = x ++ rs', diff = |x|
if (rs.size() > i) {
unsigned diff = rs.size() - (i + 1);
for (unsigned j = 0; same && j < i; ++j) {
same = eq_unit(ls[j], rs[diff + j]);
}
if (same) {
m_overlap_lhs.insert(pair, true);
return true;
}
}
if (same)
result.push_back(i+1);
}
#if 0
if (eq_unit(ls[i], rs[0])) {
bool same = ls.size() - i >= rs.size();
for (unsigned j = 0; same && j < rs.size(); ++j) {
same = eq_unit(ls[i+j], rs[j]);
// ls = x ++ rs ++ y, diff = |x|
else {
unsigned diff = (i + 1) - rs.size();
for (unsigned j = 0; same && j < rs.size()-1; ++j) {
same = eq_unit(ls[diff + j], rs[j]);
}
if (same) {
m_overlap_lhs.insert(pair, true);
return true;
}
}
if (same)
result.push_back(i);
}
#endif
}
m_overlap.insert(pair, result);
return result;
m_overlap_lhs.insert(pair, false);
return false;
}
// exists x, y, rs' != empty s.t. (ls = x ++ rs' ++ y & rs = rs') || (ls = x ++ rs' && rs = rs' ++ y)
unsigned_vector theory_seq::overlap2(expr_ref_vector const& ls, expr_ref_vector const& rs) {
// exists x, y, rs' != empty s.t. (ls = x ++ rs ++ y) || (ls = x ++ rs' && rs = rs' ++ y)
bool theory_seq::can_align_from_rhs(expr_ref_vector const& ls, expr_ref_vector const& rs) {
SASSERT(!ls.empty() && !rs.empty());
unsigned_vector res;
expr_ref l = mk_concat(ls);
expr_ref r = mk_concat(rs);
expr_ref pair(m.mk_eq(l,r), m);
if (m_overlap2.find(pair, res)) {
return res;
bool result;
if (m_overlap_rhs.find(pair, result)) {
return result;
}
unsigned_vector result;
for (unsigned i = 0; i < ls.size(); ++i) {
if (eq_unit(ls[i], rs[0])) {
unsigned diff = ls.size()-1-i;
if (eq_unit(ls[diff], rs[0])) {
bool same = true;
unsigned j = i+1;
while (j < ls.size() && j-i < rs.size()) {
if (!eq_unit(ls[j], rs[j-i])) {
same = false;
break;
// ls = x ++ rs' && rs = rs' ++ y, diff = |x|
if (rs.size() > i) {
for (unsigned j = 1; same && j <= i; ++j) {
same = eq_unit(ls[diff+j], rs[j]);
}
if (same) {
m_overlap_rhs.insert(pair, true);
return true;
}
++j;
}
if (same)
result.push_back(i);
}
}
m_overlap2.insert(pair, result);
return result;
}
bool theory_seq::branch_ternary_variable_base(
dependency* dep, unsigned_vector const& indexes,
expr* x, expr_ref_vector const& xs, expr* y1, expr_ref_vector const& ys, expr* y2) {
bool change = false;
for (auto ind : indexes) {
TRACE("seq", tout << "ind = " << ind << "\n";);
expr_ref xs2E(m);
xs2E = mk_concat(xs.size()-ind, xs.c_ptr()+ind, m.get_sort(x));
literal lit1 = mk_literal(m_autil.mk_le(mk_len(y2), m_autil.mk_int(xs.size()-ind)));
switch (ctx.get_assignment(lit1)) {
case l_undef:
TRACE("seq", tout << "base case init\n";);
ctx.mark_as_relevant(lit1);
ctx.force_phase(lit1);
change = true;
break;
case l_true:
TRACE("seq", tout << "base case: true branch\n";);
propagate_eq(dep, lit1, y2, xs2E, true);
if (ind > ys.size()) {
expr_ref xs1E = mk_concat(ind-ys.size(), xs.c_ptr(), m.get_sort(x));
expr_ref xxs1E = mk_concat(x, xs1E);
propagate_eq(dep, lit1, xxs1E, y1, true);
}
else if (ind == ys.size()) {
propagate_eq(dep, lit1, x, y1, true);
}
// ls = x ++ rs ++ y, diff = |x|
else {
expr_ref ys1E = mk_concat(ys.size()-ind, ys.c_ptr(), m.get_sort(x));
expr_ref y1ys1E = mk_concat(y1, ys1E);
propagate_eq(dep, lit1, x, y1ys1E, true);
for (unsigned j = 1; same && j < rs.size(); ++j) {
same = eq_unit(ls[diff + j], rs[j]);
}
if (same) {
m_overlap_rhs.insert(pair, true);
return true;
}
}
return true;
default:
TRACE("seq", tout << "base case: false branch\n";);
break;
}
}
return change;
m_overlap_rhs.insert(pair, false);
return false;
}
// Equation is of the form x ++ xs = y1 ++ ys ++ y2 where xs, ys are units.
bool theory_seq::branch_ternary_variable(eq const& e, bool flag1) {
// If xs and ys cannot align then
// x ++ xs = y1 ++ ys ++ y2 => x = y1 ++ ys ++ z, z ++ xs = y2
bool theory_seq::branch_ternary_variable_rhs(eq const& e) {
expr_ref_vector xs(m), ys(m);
expr_ref x(m), y1(m), y2(m);
if (!is_ternary_eq(e.ls(), e.rs(), x, xs, y1, ys, y2, flag1) &&
!is_ternary_eq(e.rs(), e.ls(), x, xs, y1, ys, y2, flag1)) {
if (!is_ternary_eq_rhs(e.ls(), e.rs(), x, xs, y1, ys, y2) &&
!is_ternary_eq_rhs(e.rs(), e.ls(), x, xs, y1, ys, y2)) {
return false;
}
@ -892,90 +866,34 @@ bool theory_seq::branch_ternary_variable(eq const& e, bool flag1) {
}
SASSERT(!xs.empty() && !ys.empty());
unsigned_vector indexes = overlap(xs, ys);
if (branch_ternary_variable_base(e.dep(), indexes, x, xs, y1, ys, y2))
if (!can_align_from_lhs(xs, ys)) {
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref y1ys = mk_concat(y1, ysE);
expr_ref Z = m_sk.mk_align_r(xsE, y1, ysE, y2);
expr_ref ZxsE = mk_concat(Z, xsE);
expr_ref y1ysZ = mk_concat(y1ys, Z);
dependency* dep = e.dep();
propagate_lit(dep, 0, nullptr, m_ax.mk_ge(mk_len(y2), xs.size()));
propagate_lit(dep, 0, nullptr, m_ax.mk_ge(mk_sub(mk_len(x), mk_len(y1)), ys.size()));
propagate_eq(dep, x, y1ysZ, true);
propagate_eq(dep, y2, ZxsE, true);
return true;
// x ++ xs = y1 ++ ys ++ y2 => x = y1 ++ ys ++ z, z ++ xs = y2
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref y1ys = mk_concat(y1, ysE);
expr_ref Z = m_sk.mk_align(y2, xsE, x, y1ys);
expr_ref ZxsE = mk_concat(Z, xsE);
expr_ref y1ysZ = mk_concat(y1ys, Z);
if (indexes.empty()) {
return false;
}
literal ge = m_ax.mk_ge(mk_len(y2), xs.size());
dependency* dep = e.dep();
switch (ctx.get_assignment(ge)) {
case l_undef:
TRACE("seq", tout << "rec case init\n";);
ctx.mark_as_relevant(ge);
ctx.force_phase(ge);
break;
case l_true:
TRACE("seq", tout << "true branch\n";);
TRACE("seq", display_equation(tout, e););
propagate_eq(dep, ge, x, y1ysZ, true);
propagate_eq(dep, ge, y2, ZxsE, true);
break;
default:
return branch_ternary_variable_base(dep, indexes, x, xs, y1, ys, y2);
}
return true;
}
bool theory_seq::branch_ternary_variable_base2(
dependency* dep, unsigned_vector const& indexes,
expr_ref_vector const& xs, expr* x, expr* y1, expr_ref_vector const& ys, expr* y2) {
sort* srt = m.get_sort(x);
bool change = false;
for (auto ind : indexes) {
expr_ref xs1E = mk_concat(ind, xs.c_ptr(), m.get_sort(x));
literal le = m_ax.mk_le(mk_len(y1), ind);
switch (ctx.get_assignment(le)) {
case l_undef:
TRACE("seq", tout << "base case init\n";);
ctx.mark_as_relevant(le);
ctx.force_phase(le);
change = true;
break;
case l_true:
TRACE("seq", tout << "base case: true branch\n";);
propagate_eq(dep, le, y1, xs1E, true);
if (xs.size() - ind > ys.size()) {
expr_ref xs2E = mk_concat(xs.size()-ind-ys.size(), xs.c_ptr()+ind+ys.size(), srt);
expr_ref xs2x = mk_concat(xs2E, x);
propagate_eq(dep, le, xs2x, y2, true);
}
else if (xs.size() - ind == ys.size()) {
propagate_eq(dep, le, x, y2, true);
}
else {
expr_ref ys1E = mk_concat(ys.size()-xs.size()+ind, ys.c_ptr()+xs.size()-ind, srt);
expr_ref ys1y2 = mk_concat(ys1E, y2);
propagate_eq(dep, le, x, ys1y2, true);
}
return true;
default:
TRACE("seq", tout << "base case: false branch\n";);
break;
}
}
return change;
return false;
}
// Equation is of the form xs ++ x = y1 ++ ys ++ y2 where xs, ys are units.
bool theory_seq::branch_ternary_variable2(eq const& e, bool flag1) {
// If xs and ys cannot align then
// xs ++ x = y1 ++ ys ++ y2 => xs ++ z = y1, x = z ++ ys ++ y2
bool theory_seq::branch_ternary_variable_lhs(eq const& e) {
expr_ref_vector xs(m), ys(m);
expr_ref x(m), y1(m), y2(m);
if (!is_ternary_eq2(e.ls(), e.rs(), xs, x, y1, ys, y2, flag1) &&
!is_ternary_eq2(e.rs(), e.ls(), xs, x, y1, ys, y2, flag1))
if (!is_ternary_eq_lhs(e.ls(), e.rs(), xs, x, y1, ys, y2) &&
!is_ternary_eq_lhs(e.rs(), e.ls(), xs, x, y1, ys, y2))
return false;
dependency* dep = e.dep();
rational lenX, lenY1, lenY2;
if (!get_length(x, lenX)) {
add_length_to_eqc(x);
@ -987,43 +905,23 @@ bool theory_seq::branch_ternary_variable2(eq const& e, bool flag1) {
add_length_to_eqc(y2);
}
SASSERT(!xs.empty() && !ys.empty());
unsigned_vector indexes = overlap2(xs, ys);
if (branch_ternary_variable_base2(dep, indexes, xs, x, y1, ys, y2))
return true;
// xs ++ x = y1 ++ ys ++ y2 => xs ++ z = y1, x = z ++ ys ++ y2
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref ysy2 = mk_concat(ysE, y2);
expr_ref Z = m_sk.mk_align(x, ysy2, y1, xsE);
expr_ref xsZ = mk_concat(xsE, Z);
expr_ref Zysy2 = mk_concat(Z, ysy2);
if (indexes.empty()) {
TRACE("seq", tout << "one case\n";);
TRACE("seq", display_equation(tout, e););
literal_vector lits;
propagate_eq(dep, lits, x, Zysy2, true);
propagate_eq(dep, lits, y1, xsZ, true);
}
else {
literal ge = m_ax.mk_ge(mk_len(y1), xs.size());
switch (ctx.get_assignment(ge)) {
case l_undef:
TRACE("seq", tout << "rec case init\n";);
ctx.mark_as_relevant(ge);
ctx.force_phase(ge);
break;
case l_true:
TRACE("seq", display_equation(tout << "true branch\n", e););
propagate_eq(dep, ge, x, Zysy2, true);
propagate_eq(dep, ge, y1, xsZ, true);
break;
default:
return branch_ternary_variable_base2(dep, indexes, xs, x, y1, ys, y2);
}
}
return true;
if (!can_align_from_rhs(xs, ys)) {
expr_ref xsE = mk_concat(xs);
expr_ref ysE = mk_concat(ys);
expr_ref ysy2 = mk_concat(ysE, y2);
expr_ref Z = m_sk.mk_align_l(xsE, y1, ysE, y2);
expr_ref xsZ = mk_concat(xsE, Z);
expr_ref Zysy2 = mk_concat(Z, ysy2);
dependency* dep = e.dep();
propagate_lit(dep, 0, nullptr, m_ax.mk_ge(mk_len(y1), xs.size()));
propagate_lit(dep, 0, nullptr, m_ax.mk_ge(mk_sub(mk_len(x), mk_len(y2)), ys.size()));
propagate_eq(dep, x, Zysy2, true);
propagate_eq(dep, y1, xsZ, true);
return true;
}
return false;
}
bool theory_seq::branch_quat_variable() {
@ -1035,14 +933,34 @@ bool theory_seq::branch_quat_variable() {
return false;
}
/*
* Two properties of align_m
* align_m(align_m(x1, x, _, _), align_m(y1, x, _, _), z, t) = align_m(x1, y1, z, t)
* align_m(x1, x, _, _) - align_m(y1, x, _, _) = x1 - y1
*/
literal theory_seq::mk_alignment(expr* e1, expr* e2) {
if (m_sk.is_align(e1) && m_sk.is_align(e2)) {
expr* x1 = to_app(e1)->get_arg(0);
expr* x2 = to_app(e1)->get_arg(1);
expr* y1 = to_app(e2)->get_arg(0);
expr* y2 = to_app(e2)->get_arg(1);
if (x2 == y2 && x1 != y1) {
return mk_alignment(x1, y1);
}
}
return mk_simplified_literal(m_autil.mk_le(mk_sub(mk_len(e1), mk_len(e2)), m_autil.mk_int(0)));
}
// Equation is of the form x1 ++ xs ++ x2 = y1 ++ ys ++ y2 where xs, ys are units.
// If xs and ys cannot align then
// x1 ++ xs ++ x2 = y1 ++ ys ++ y2 => |x1| >= |y1 ++ ys| V |x1 ++ xs| <= |y1|
bool theory_seq::branch_quat_variable(eq const& e) {
expr_ref_vector xs(m), ys(m);
expr_ref x1(m), x2(m), y1(m), y2(m);
if (!is_quat_eq(e.ls(), e.rs(), x1, xs, x2, y1, ys, y2))
return false;
dependency* dep = e.dep();
rational lenX1, lenX2, lenY1, lenY2;
if (!get_length(x1, lenX1)) {
add_length_to_eqc(x1);
@ -1057,48 +975,119 @@ bool theory_seq::branch_quat_variable(eq const& e) {
add_length_to_eqc(y2);
}
SASSERT(!xs.empty() && !ys.empty());
xs.push_back(x2);
expr_ref xsx2 = mk_concat(xs);
ys.push_back(y2);
expr_ref ysy2 = mk_concat(ys);
expr_ref sub(mk_sub(mk_len(x1), mk_len(y1)), m);
literal le = m_ax.mk_le(sub, 0);
switch (ctx.get_assignment(le)) {
case l_undef:
TRACE("seq", tout << "init branch\n";);
TRACE("seq", display_equation(tout, e););
ctx.mark_as_relevant(le);
ctx.force_phase(le);
break;
case l_false: {
// |x1| > |y1| => x1 = y1 ++ z1, z1 ++ xs ++ x2 = ys ++ y2
TRACE("seq", tout << "false branch\n";);
TRACE("seq", display_equation(tout, e););
expr_ref Z1 = m_sk.mk_align(ysy2, xsx2, x1, y1);
expr_ref y1Z1 = mk_concat(y1, Z1);
expr_ref Z1xsx2 = mk_concat(Z1, xsx2);
propagate_eq(dep, ~le, x1, y1Z1, true);
propagate_eq(dep, ~le, Z1xsx2, ysy2, true);
break;
bool cond = false;
// xs and ys cannot align
if (!can_align_from_lhs(xs, ys) && !can_align_from_rhs(xs, ys))
cond = true;
// xs = ys and xs and ys cannot align except the case xs = ys
else if (xs == ys) {
expr_ref_vector xs1(m), xs2(m);
xs1.reset();
xs1.append(xs.size()-1, xs.c_ptr()+1);
xs2.reset();
xs2.append(xs.size()-1, xs.c_ptr());
if (!can_align_from_lhs(xs2, ys) && !can_align_from_rhs(xs1, ys))
cond = true;
}
case l_true: {
// |x1| <= |y1| => x1 ++ z2 = y1, xs ++ x2 = z2 ++ ys ++ y2
TRACE("seq", tout << "true branch\n";);
TRACE("seq", display_equation(tout, e););
expr_ref Z2 = m_sk.mk_align(xsx2, ysy2, y1, x1);
expr_ref x1Z2 = mk_concat(x1, Z2);
expr_ref Z2ysy2 = mk_concat(Z2, ysy2);
propagate_eq(dep, le, x1Z2, y1, true);
propagate_eq(dep, le, xsx2, Z2ysy2, true);
break;
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);
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);
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);
propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
return true;
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit3) == l_true) {
lits.push_back(lit1);
lits.push_back(lit3);
propagate_lit(nullptr, lits.size(), lits.c_ptr(), false_literal);
return true;
}
if (ctx.get_assignment(lit1) == l_true && ctx.get_assignment(lit2) == l_false) {
lits.push_back(lit1);
lits.push_back(~lit2);
propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
return true;
}
if (ctx.get_assignment(lit1) == l_false && ctx.get_assignment(lit3) == l_false) {
lits.push_back(~lit1);
lits.push_back(~lit3);
propagate_lit(dep, lits.size(), lits.c_ptr(), false_literal);
return true;
}
UNREACHABLE();
}
}
return true;
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];
@ -1478,8 +1467,8 @@ bool theory_seq::is_binary_eq(expr_ref_vector const& ls, expr_ref_vector const&
match: X abc Y..Y' = Z def T..T', where X,Z are variables or concatenation of variables
*/
bool theory_seq::is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref& x1, expr_ref_vector& xs, expr_ref& x2,
bool theory_seq::is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref& x1, expr_ref_vector& xs, expr_ref& x2,
expr_ref& y1, expr_ref_vector& ys, expr_ref& y2) {
if (ls.size() > 1 && is_var(ls[0]) && is_var(ls.back()) &&
rs.size() > 1 && is_var(rs[0]) && is_var(rs.back())) {
@ -1494,6 +1483,7 @@ bool theory_seq::is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs
if (!m_util.str.is_unit(ls[l_end])) break;
}
--l_end;
if (l_end < l_start) return false;
unsigned r_start = 1;
for (; r_start < rs.size()-1; ++r_start) {
if (m_util.str.is_unit(rs[r_start])) break;
@ -1504,12 +1494,7 @@ bool theory_seq::is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs
if (!m_util.str.is_unit(rs[r_end])) break;
}
--r_end;
for (unsigned i = l_start; i < l_end+1; ++i) {
if (!m_util.str.is_unit(ls[i])) return false;
}
for (unsigned i = r_start; i < r_end+1; ++i) {
if (!m_util.str.is_unit(rs[i])) return false;
}
if (r_end < r_start) return false;
xs.reset();
xs.append(l_end-l_start+1, ls.c_ptr()+l_start);
x1 = mk_concat(l_start, ls.c_ptr(), srt);
@ -1524,16 +1509,13 @@ bool theory_seq::is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs
}
/*
match: X..X' abc = Y..Y' mnp Z // flag1 = false
e..X abc = Y..Y' mnp Z // flag1 = true
match: .. X abc = .. Y def Z
where Z is a variable or concatenation of variables
*/
bool theory_seq::is_ternary_eq(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref& x, expr_ref_vector& xs, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2, bool flag1) {
if (ls.size() > 1 && (is_var(ls[0]) || flag1) &&
rs.size() > 1 && is_var(rs[0]) && is_var(rs.back())) {
bool theory_seq::is_ternary_eq_rhs(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref& x, expr_ref_vector& xs, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2) {
if (ls.size() > 1 && rs.size() > 1 && is_var(rs[0]) && is_var(rs.back())) {
sort* srt = m.get_sort(ls[0]);
unsigned l_start = ls.size()-1;
for (; l_start > 0; --l_start) {
@ -1551,12 +1533,7 @@ bool theory_seq::is_ternary_eq(expr_ref_vector const& ls, expr_ref_vector const&
if (!m_util.str.is_unit(rs[r_start])) break;
}
++r_start;
for (unsigned i = l_start; i < ls.size(); ++i) {
if (!m_util.str.is_unit(ls[i])) return false;
}
for (unsigned i = r_start; i < r_end+1; ++i) {
if (!m_util.str.is_unit(rs[i])) return false;
}
xs.reset();
xs.append(ls.size()-l_start, ls.c_ptr()+l_start);
x = mk_concat(l_start, ls.c_ptr(), srt);
@ -1570,15 +1547,13 @@ bool theory_seq::is_ternary_eq(expr_ref_vector const& ls, expr_ref_vector const&
}
/*
match: abc X..X' = Y def Z..Z' // flag1 is false
abc X..e = Y def Z..Z' // flag1 is true
match: abc X .. = Y def Z ..
where Y is a variable or concatenation of variables
*/
bool theory_seq::is_ternary_eq2(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref_vector& xs, expr_ref& x, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2, bool flag1) {
if (ls.size() > 1 && (is_var(ls.back()) || flag1) &&
rs.size() > 1 && is_var(rs[0]) && is_var(rs.back())) {
bool theory_seq::is_ternary_eq_lhs(expr_ref_vector const& ls, expr_ref_vector const& rs,
expr_ref_vector& xs, expr_ref& x, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2) {
if (ls.size() > 1 && rs.size() > 1 && is_var(rs[0]) && is_var(rs.back())) {
sort* srt = m.get_sort(ls[0]);
unsigned l_start = 0;
for (; l_start < ls.size()-1; ++l_start) {
@ -1595,12 +1570,7 @@ bool theory_seq::is_ternary_eq2(expr_ref_vector const& ls, expr_ref_vector const
if (!m_util.str.is_unit(rs[r_end])) break;
}
--r_end;
for (unsigned i = 0; i < l_start; ++i) {
if (!m_util.str.is_unit(ls[i])) return false;
}
for (unsigned i = r_start; i < r_end+1; ++i) {
if (!m_util.str.is_unit(rs[i])) return false;
}
xs.reset();
xs.append(l_start, ls.c_ptr());
x = mk_concat(ls.size()-l_start, ls.c_ptr()+l_start, srt);

1
src/smt/seq_skolem.cpp
View file

@ -34,7 +34,6 @@ seq_skolem::seq_skolem(ast_manager& m, th_rewriter& rw):
m_pre = "seq.pre"; // (seq.pre s l): prefix of string s of length l
m_post = "seq.post"; // (seq.post s l): suffix of string s of length k, based on extract starting at index i of length l
m_eq = "seq.eq";
m_seq_align = "seq.align";
m_max_unfolding = "seq.max_unfolding";
m_length_limit = "seq.length_limit";
m_is_empty = "re.is_empty";

17
src/smt/seq_skolem.h
View file

@ -39,7 +39,6 @@ namespace smt {
symbol m_is_empty, m_is_non_empty; // regex emptiness check
symbol m_pre, m_post; // inverse of at: (pre s i) + (at s i) + (post s i) = s if 0 <= i < (len s)
symbol m_eq; // equality atom
symbol m_seq_align;
symbol m_max_unfolding, m_length_limit;
public:
@ -58,7 +57,20 @@ namespace smt {
return mk(symbol(s), e1, e2, e3, e4, range);
}
expr_ref mk_align(expr* e1, expr* e2, expr* e3, expr* e4) { return mk(m_seq_align, e1, e2, e3, e4); }
expr_ref mk_align(expr* e1, expr* e2, expr* e3, expr* e4) { return mk("seq.align", e1, e2, e3, e4); }
expr_ref mk_align_l(expr* e1, expr* e2, expr* e3, expr* e4) { return mk("seq.align.l", e1, e2, e3, e4); }
expr_ref mk_align_r(expr* e1, expr* e2, expr* e3, expr* e4) { return mk("seq.align.r", e1, e2, e3, e4); }
expr_ref mk_align_m(expr* e1, expr* e2, expr* e3, expr* e4) {
if (is_align(e1) && is_align(e2)) {
expr* x1 = to_app(e1)->get_arg(0);
expr* x2 = to_app(e1)->get_arg(1);
expr* y1 = to_app(e2)->get_arg(0);
expr* y2 = to_app(e2)->get_arg(1);
if (x2 == y2 && x1 != y1)
return mk_align_m(x1, y1, e3, e4);
}
return mk("seq.align.m", e1, e2, e3, e4);
}
expr_ref mk_accept(expr_ref_vector const& args) { return expr_ref(seq.mk_skolem(m_accept, args.size(), args.c_ptr(), m.mk_bool_sort()), m); }
expr_ref mk_accept(expr* s, expr* i, expr* r) { return mk(m_accept, s, i, r, nullptr, m.mk_bool_sort()); }
expr_ref mk_is_non_empty(expr* r, expr* u) { return mk(m_is_non_empty, r, u, m.mk_bool_sort()); }
@ -112,6 +124,7 @@ namespace smt {
r = to_app(e)->get_arg(2), true) &&
a.is_unsigned(i, idx);
}
bool is_align(expr* e) const { return is_skolem(symbol("seq.align.m"), e); }
bool is_post(expr* e, expr*& s, expr*& start);
bool is_pre(expr* e, expr*& s, expr*& i);
bool is_eq(expr* e, expr*& a, expr*& b) const;

4
src/smt/theory_seq.cpp
View file

@ -281,8 +281,8 @@ theory_seq::theory_seq(context& ctx):
m_eq_id(0),
m_find(*this),
m_offset_eq(*this, m),
m_overlap(m),
m_overlap2(m),
m_overlap_lhs(m),
m_overlap_rhs(m),
m_factory(nullptr),
m_exclude(m),
m_axioms(m),

25
src/smt/theory_seq.h
View file

@ -382,8 +382,8 @@ namespace smt {
th_union_find m_find;
seq_offset_eq m_offset_eq;
obj_ref_map<ast_manager, expr, unsigned_vector> m_overlap;
obj_ref_map<ast_manager, expr, unsigned_vector> m_overlap2;
obj_ref_map<ast_manager, expr, bool> m_overlap_lhs;
obj_ref_map<ast_manager, expr, bool> m_overlap_rhs;
seq_factory* m_factory; // value factory
@ -476,8 +476,7 @@ namespace smt {
bool branch_unit_variable(); // branch on XYZ = abcdef
bool branch_binary_variable(); // branch on abcX = Ydefg
bool branch_variable(); // branch on
bool branch_ternary_variable1(); // branch on XabcY = Zdefg
bool branch_ternary_variable2(); // branch on XabcY = defgZ
bool branch_ternary_variable(); // branch on XabcY = Zdefg
bool branch_quat_variable(); // branch on XabcY = ZdefgT
bool len_based_split(); // split based on len offset
bool branch_variable_mb(); // branch on a variable, model based on length
@ -492,14 +491,11 @@ namespace smt {
bool branch_variable_eq(eq const& e);
bool branch_binary_variable(eq const& e);
bool eq_unit(expr* l, expr* r) const;
unsigned_vector overlap(expr_ref_vector const& ls, expr_ref_vector const& rs);
unsigned_vector overlap2(expr_ref_vector const& ls, expr_ref_vector const& rs);
bool branch_ternary_variable_base(dependency* dep, unsigned_vector const & indexes, expr * x,
expr_ref_vector const& xs, expr * y1, expr_ref_vector const& ys, expr * y2);
bool branch_ternary_variable_base2(dependency* dep, unsigned_vector const& indexes, expr_ref_vector const& xs,
expr * x, expr * y1, expr_ref_vector const& ys, expr * y2);
bool branch_ternary_variable(eq const& e, bool flag1 = false);
bool branch_ternary_variable2(eq const& e, bool flag1 = false);
bool can_align_from_lhs(expr_ref_vector const& ls, expr_ref_vector const& rs);
bool can_align_from_rhs(expr_ref_vector const& ls, expr_ref_vector const& rs);
bool branch_ternary_variable_rhs(eq const& e);
bool branch_ternary_variable_lhs(eq const& e);
literal mk_alignment(expr* e1, expr* e2);
bool branch_quat_variable(eq const& e);
bool len_based_split(eq const& e);
bool is_unit_eq(expr_ref_vector const& ls, expr_ref_vector const& rs);
@ -526,8 +522,9 @@ namespace smt {
bool solve_itos(expr* n, expr_ref_vector const& rs, dependency* dep);
bool is_binary_eq(expr_ref_vector const& l, expr_ref_vector const& r, expr_ref& x, ptr_vector<expr>& xunits, ptr_vector<expr>& yunits, expr_ref& y);
bool is_quat_eq(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref& x1, expr_ref_vector& xs, expr_ref& x2, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2);
bool is_ternary_eq(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref& x, expr_ref_vector& xs, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2, bool flag1);
bool is_ternary_eq2(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref_vector& xs, expr_ref& x, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2, bool flag1);
bool is_ternary_eq_rhs(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref& x, expr_ref_vector& xs, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2);
bool is_ternary_eq_lhs(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref_vector& xs, expr_ref& x, expr_ref& y1, expr_ref_vector& ys, expr_ref& y2);
bool solve_binary_eq(expr_ref_vector const& l, expr_ref_vector const& r, dependency* dep);
bool propagate_max_length(expr* l, expr* r, dependency* dep);