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register unhandled expressions

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-06-12 16:12:24 -07:00
parent 2613f74baa
commit 41430cd128
5 changed files with 63 additions and 25 deletions
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30
src/smt/seq_regex.cpp
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@ -101,7 +101,7 @@ namespace smt {
expr* e = ctx.bool_var2expr(lit.var());
VERIFY(str().is_in_re(e, s, r));
TRACE("seq", tout << "propagate " << mk_pp(e, m) << "\n";);
TRACE("seq", tout << "propagate " << lit.sign() << " " << mk_pp(e, m) << "\n";);
// convert negative negative membership literals to positive
// ~(s in R) => s in C(R)
@ -109,6 +109,10 @@ namespace smt {
expr_ref fml(re().mk_in_re(s, re().mk_complement(r)), m);
rewrite(fml);
literal nlit = th.mk_literal(fml);
if (lit == nlit) {
// is-nullable doesn't simplify for regexes with uninterpreted subterms
th.add_unhandled_expr(fml);
}
th.propagate_lit(nullptr, 1, &lit, nlit);
return;
}
@ -138,6 +142,8 @@ namespace smt {
expr_ref acc = sk().mk_accept(s, zero, r);
literal acc_lit = th.mk_literal(acc);
TRACE("seq", tout << "propagate " << acc << "\n";);
th.propagate_lit(nullptr, 1, &lit, acc_lit);
}
@ -177,7 +183,7 @@ namespace smt {
if (block_unfolding(lit, idx))
return true;
propagate_nullable(lit, e, s, idx, r);
propagate_nullable(lit, s, idx, r);
return propagate_derivative(lit, e, s, i, idx, r);
}
@ -187,9 +193,21 @@ namespace smt {
(accept s i r) => len(s) >= i
(accept s i r) & ~nullable(r) => len(s) >= i + 1
evaluate nullable(r):
nullable(r) := true -> propagate: (accept s i r) => len(s) >= i
nullable(r) := false -> propagate: (accept s i r) => len(s) >= i + 1
Otherwise:
propagate: (accept s i r) => len(s) >= i
evaluate len(s) <= i:
len(s) <= i := undef -> axiom: (accept s i r) & len(s) <= i => nullable(r)
len(s) <= i := true -> propagate: (accept s i r) & len(s) <= i => nullable(r)
len(s) <= i := false -> noop.
*/
void seq_regex::propagate_nullable(literal lit, expr* e, expr* s, unsigned idx, expr* r) {
void seq_regex::propagate_nullable(literal lit, expr* s, unsigned idx, expr* r) {
expr_ref is_nullable = seq_rw().is_nullable(r);
rewrite(is_nullable);
literal len_s_ge_i = th.m_ax.mk_ge(th.mk_len(s), idx);
@ -200,14 +218,16 @@ namespace smt {
th.propagate_lit(nullptr, 1, &lit, th.m_ax.mk_ge(th.mk_len(s), idx + 1));
}
else {
literal is_nullable_lit = th.mk_literal(is_nullable);
ctx.mark_as_relevant(is_nullable_lit);
literal len_s_le_i = th.m_ax.mk_le(th.mk_len(s), idx);
switch (ctx.get_assignment(len_s_le_i)) {
case l_undef:
th.add_axiom(~lit, ~len_s_le_i, th.mk_literal(is_nullable));
th.add_axiom(~lit, ~len_s_le_i, is_nullable_lit);
break;
case l_true: {
literal lits[2] = { lit, len_s_le_i };
th.propagate_lit(nullptr, 2, lits, th.mk_literal(is_nullable));
th.propagate_lit(nullptr, 2, lits, is_nullable_lit);
break;
}
case l_false: