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add option to rewrite and for arithmetic simplification

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This commit is contained in:
Nikolaj Bjorner 2022-09-18 17:17:47 -07:00
parent 088898834c
commit bd4db4c41f
5 changed files with 47 additions and 10 deletions
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25
src/ast/rewriter/arith_rewriter.cpp
View file

@ -706,6 +706,31 @@ br_status arith_rewriter::mk_eq_core(expr * arg1, expr * arg2, expr_ref & result
return st;
}
br_status arith_rewriter::mk_and_core(unsigned n, expr* const* args, expr_ref& result) {
if (n <= 1)
return BR_FAILED;
expr* x, * y, * z, * u;
rational a, b;
if (m_util.is_le(args[0], x, y) && m_util.is_numeral(x, a)) {
expr* arg0 = args[0];
ptr_buffer<expr> rest;
for (unsigned i = 1; i < n; ++i) {
if (m_util.is_le(args[i], z, u) && u == y && m_util.is_numeral(z, b)) {
if (b > a)
arg0 = args[i];
}
else
rest.push_back(args[i]);
}
if (rest.size() < n - 1) {
rest.push_back(arg0);
result = m().mk_and(rest);
return BR_REWRITE1;
}
}
return BR_FAILED;
}
bool arith_rewriter::mk_eq_mod(expr* arg1, expr* arg2, expr_ref& result) {
expr* x = nullptr, *y = nullptr, *z = nullptr, *u = nullptr;
rational p, k, l;

2
src/ast/rewriter/arith_rewriter.h
View file

@ -149,6 +149,8 @@ public:
br_status mk_abs_core(expr * arg, expr_ref & result);
br_status mk_and_core(unsigned n, expr* const* args, expr_ref& result);
br_status mk_div_core(expr * arg1, expr * arg2, expr_ref & result);
br_status mk_idiv_core(expr * arg1, expr * arg2, expr_ref & result);
br_status mk_idivides(unsigned k, expr * arg, expr_ref & result);

20
src/ast/rewriter/bool_rewriter.cpp
View file

@ -175,7 +175,7 @@ br_status bool_rewriter::mk_flat_and_core(unsigned num_args, expr * const * args
}
if (mk_nflat_and_core(flat_args.size(), flat_args.data(), result) == BR_FAILED)
result = m().mk_and(flat_args);
return BR_DONE;
return BR_REWRITE1;
}
return mk_nflat_and_core(num_args, args, result);
}
@ -874,7 +874,7 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
expr_ref tmp(m());
mk_not(c, tmp);
mk_and(tmp, e, result);
return BR_DONE;
return BR_REWRITE1;
}
}
if (m().is_true(e) && m_elim_ite) {
@ -885,11 +885,11 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
}
if (m().is_false(e) && m_elim_ite) {
mk_and(c, t, result);
return BR_DONE;
return BR_REWRITE1;
}
if (c == e && m_elim_ite) {
mk_and(c, t, result);
return BR_DONE;
return BR_REWRITE1;
}
if (c == t && m_elim_ite) {
mk_or(c, e, result);
@ -912,13 +912,13 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
expr_ref a(m());
mk_and(c, t2, a);
result = m().mk_not(m().mk_eq(t1, a));
return BR_REWRITE2;
return BR_REWRITE3;
}
if (m().is_not(t, t1) && m().is_eq(t1, t2, t1) && e == t1) {
expr_ref a(m());
mk_and(c, t2, a);
result = m().mk_eq(t1, a);
return BR_REWRITE2;
return BR_REWRITE3;
}
#endif
@ -931,14 +931,14 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
expr_ref new_c(m());
mk_and(c, not_c2, new_c);
result = m().mk_ite(new_c, to_app(t)->get_arg(2), e);
return BR_REWRITE1;
return BR_REWRITE2;
}
// (ite c1 (ite c2 t1 t2) t2) ==> (ite (and c1 c2) t1 t2)
if (e == to_app(t)->get_arg(2)) {
expr_ref new_c(m());
mk_and(c, to_app(t)->get_arg(0), new_c);
result = m().mk_ite(new_c, to_app(t)->get_arg(1), e);
return BR_REWRITE1;
return BR_REWRITE2;
}
@ -955,7 +955,7 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
expr_ref new_c(m());
mk_or(and1, and2, new_c);
result = m().mk_ite(new_c, to_app(t)->get_arg(1), to_app(t)->get_arg(2));
return BR_REWRITE1;
return BR_REWRITE3;
}
// (ite c1 (ite c2 t1 t2) (ite c3 t2 t1)) ==> (ite (or (and c1 c2) (and (not c1) (not c3))) t1 t2)
@ -972,7 +972,7 @@ br_status bool_rewriter::mk_ite_core(expr * c, expr * t, expr * e, expr_ref & re
expr_ref new_c(m());
mk_or(and1, and2, new_c);
result = m().mk_ite(new_c, to_app(t)->get_arg(1), to_app(t)->get_arg(2));
return BR_REWRITE1;
return BR_REWRITE3;
}
}
}

5
src/ast/rewriter/th_rewriter.cpp
View file

@ -215,6 +215,11 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
if (st != BR_FAILED)
return st;
}
if (false && k == OP_AND) {
st = m_a_rw.mk_and_core(num, args, result);
if (st != BR_FAILED)
return st;
}
if (k == OP_EQ && m_seq_rw.u().has_seq() && is_app(args[0]) &&
to_app(args[0])->get_family_id() == m_seq_rw.get_fid()) {
st = m_seq_rw.mk_eq_core(args[0], args[1], result);

5
src/model/model_evaluator.cpp
View file

@ -262,6 +262,11 @@ struct evaluator_cfg : public default_rewriter_cfg {
if (st != BR_FAILED)
return st;
}
if (k == OP_AND) {
st = m_a_rw.mk_and_core(num, args, result);
if (st != BR_FAILED)
return st;
}
return m_b_rw.mk_app_core(f, num, args, result);
}
if (fid == m_a_rw.get_fid())