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use common idioms for factor-equivalence code

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2017-08-01 21:07:20 -07:00
parent 0a6759383a
commit ce3fd22f3b
1 changed files with 11 additions and 13 deletions
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24
src/ast/factor_equivs.cpp
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@ -34,25 +34,19 @@ Revision History:
void factor_eqs(expr_ref_vector &v, expr_equiv_class &equiv) {
ast_manager &m = v.get_manager();
arith_util arith(m);
expr *e1, *e2;
expr *e1 = 0, *e2 = 0;
flatten_and(v);
unsigned j = 0;
for (unsigned i = 0; i < v.size(); ++i) {
if (m.is_eq(v.get(i), e1, e2)) {
if (arith.is_zero(e1)) {
expr* t;
t = e1; e1 = e2; e2 = t;
std::swap(e1, e2);
}
// y + -1*x == 0
if (arith.is_zero(e2) && arith.is_add(e1) &&
to_app(e1)->get_num_args() == 2) {
expr *a0, *a1, *x;
a0 = to_app(e1)->get_arg(0);
a1 = to_app(e1)->get_arg(1);
expr* a0 = 0, *a1 = 0, *x = 0;
if (arith.is_zero(e2) && arith.is_add(e1, a0, a1)) {
if (arith.is_times_minus_one(a1, x)) {
e1 = a0;
e2 = x;
@ -65,7 +59,9 @@ void factor_eqs(expr_ref_vector &v, expr_equiv_class &equiv) {
equiv.merge(e1, e2);
}
else {
if (j < i) {v[j] = v.get(i);}
if (j < i) {
v[j] = v.get(i);
}
j++;
}
}
@ -80,14 +76,16 @@ void equiv_to_expr(expr_equiv_class &equiv, expr_ref_vector &out) {
for (auto eq_class : equiv) {
expr *rep = nullptr;
for (expr *elem : eq_class) {
if (!m.is_value (elem)) {
if (!m.is_value(elem)) {
rep = elem;
break;
}
}
SASSERT(rep);
for (expr *elem : eq_class) {
if (rep != elem) {out.push_back (m.mk_eq (rep, elem));}
if (rep != elem) {
out.push_back (m.mk_eq (rep, elem));
}
}
}
}