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fix #4481 (#4484)

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trinhmt 2020-06-02 00:02:50 +08:00 committed by GitHub
parent c967b4aead
commit 48a2d3d5b6
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1 changed files with 15 additions and 5 deletions
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20
src/smt/seq_eq_solver.cpp
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@ -775,6 +775,10 @@ bool theory_seq::can_align_from_lhs(expr_ref_vector const& ls, expr_ref_vector c
for (unsigned i = 0; i < ls.size(); ++i) {
if (eq_unit(ls[i], rs.back())) {
bool same = true;
if (i == 0) {
m_overlap_lhs.insert(pair, true);
return true;
}
// ls = rs' ++ y && rs = x ++ rs', diff = |x|
if (rs.size() > i) {
unsigned diff = rs.size() - (i + 1);
@ -817,6 +821,10 @@ bool theory_seq::can_align_from_rhs(expr_ref_vector const& ls, expr_ref_vector c
unsigned diff = ls.size()-1-i;
if (eq_unit(ls[diff], rs[0])) {
bool same = true;
if (i == 0) {
m_overlap_rhs.insert(pair, true);
return true;
}
// ls = x ++ rs' && rs = rs' ++ y, diff = |x|
if (rs.size() > i) {
for (unsigned j = 1; same && j <= i; ++j) {
@ -973,19 +981,21 @@ bool theory_seq::branch_quat_variable(eq const& e) {
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) {
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))
if (xs1.empty() || xs2.empty())
cond = true;
else if (!can_align_from_lhs(xs2, ys) && !can_align_from_rhs(xs1, ys))
cond = true;
}
// xs and ys cannot align
else if (!can_align_from_lhs(xs, ys) && !can_align_from_rhs(xs, ys))
cond = true;
if (cond) {
literal_vector lits;