mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-08-10 21:20:52 +00:00
Code Activity

add rewrites for #2575

Browse source 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2019-09-20 08:55:53 -07:00
parent 80636dd35f
commit cd0cd82eb7
4 changed files with 78 additions and 21 deletions
Download patch file Download diff file Expand all files Collapse all files

85
src/ast/rewriter/seq_rewriter.cpp
View file

@ -441,7 +441,7 @@ br_status seq_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * con
st = mk_re_complement(args[0], result);
break;
case OP_RE_LOOP:
st = mk_re_loop(num_args, args, result);
st = mk_re_loop(f, num_args, args, result);
break;
case OP_RE_EMPTY_SET:
return BR_FAILED;
@ -1682,27 +1682,41 @@ br_status seq_rewriter::mk_re_concat(expr* a, expr* b, expr_ref& result) {
result = m_util.re.mk_concat(b, a);
return BR_DONE;
}
{
unsigned lo1, hi1, lo2, hi2;
if (m_util.re.is_loop(a, a1, lo1, hi1) && m_util.re.is_loop(b, b1, lo2, hi2) && a1 == b1) {
result = m_util.re.mk_loop(a1, lo1 + lo2, hi1 + hi2);
return BR_DONE;
}
if (m_util.re.is_loop(a, a1, lo1) && m_util.re.is_loop(b, b1, lo2) && a1 == b1) {
unsigned lo1, hi1, lo2, hi2;
if (m_util.re.is_loop(a, a1, lo1, hi1) && m_util.re.is_loop(b, b1, lo2, hi2) && a1 == b1) {
SASSERT(lo1 <= hi1 && lo2 <= hi2);
result = m_util.re.mk_loop(a1, lo1 + lo2, hi1 + hi2);
return BR_DONE;
}
if (m_util.re.is_loop(a, a1, lo1) && m_util.re.is_loop(b, b1, lo2) && a1 == b1) {
result = m_util.re.mk_loop(a1, lo1 + lo2);
return BR_DONE;
}
for (unsigned i = 0; i < 2; ++i) {
// (loop a lo1) + (loop a lo2 hi2) = (loop a lo1 + lo2)
if (m_util.re.is_loop(a, a1, lo1) && m_util.re.is_loop(b, b1, lo2, hi2) && a1 == b1) {
SASSERT(lo2 <= hi2);
result = m_util.re.mk_loop(a1, lo1 + lo2);
return BR_DONE;
}
}
{
expr* lo1, *hi1, *lo2, *hi2;
if (m_util.re.is_loop(a, a1, lo1, hi1) && m_util.re.is_loop(b, b1, lo2, hi2) && a1 == b1) {
result = m_util.re.mk_loop(a1, m_autil.mk_add(lo1, lo2), m_autil.mk_add(hi1, hi2));
// (loop a lo1 hi1) + a* = (loop a lo1)
if (m_util.re.is_loop(a, a1, lo1, hi1) && m_util.re.is_star(b, b1) && a1 == b1) {
result = m_util.re.mk_loop(a1, lo1);
return BR_DONE;
}
if (m_util.re.is_loop(a, a1, lo1) && m_util.re.is_loop(b, b1, lo2) && a1 == b1) {
result = m_util.re.mk_loop(a1, m_autil.mk_add(lo1, lo2));
// (loop a lo1) + a* = (loop a lo1)
if (m_util.re.is_loop(a, a1, lo1) && m_util.re.is_star(b, b1) && a1 == b1) {
result = a;
return BR_DONE;
}
// (loop a lo1 hi1) + a = (loop a lo1+1 hi1+1)
if (m_util.re.is_loop(a, a1, lo1, hi1) && a1 == b) {
SASSERT(lo1 <= hi1);
result = m_util.re.mk_loop(a1, lo1+1, hi1+1);
return BR_DONE;
}
std::swap(a, b);
}
return BR_FAILED;
}
@ -1804,22 +1818,55 @@ br_status seq_rewriter::mk_re_inter(expr* a, expr* b, expr_ref& result) {
}
br_status seq_rewriter::mk_re_loop(unsigned num_args, expr* const* args, expr_ref& result) {
br_status seq_rewriter::mk_re_loop(func_decl* f, unsigned num_args, expr* const* args, expr_ref& result) {
rational n1, n2;
unsigned lo, hi;
expr* a = nullptr;
switch (num_args) {
case 1:
// (loop (loop a lo hi) lo2 hi2) = (loop lo*lo2 hi*hi2)
if (m_util.re.is_loop(args[0], a, lo, hi) && f->get_num_parameters() == 2) {
result = m_util.re.mk_loop(a, f->get_parameter(0).get_int() * lo, f->get_parameter(1).get_int() * hi);
return BR_REWRITE1;
}
// (loop (loop a lo hi) lo2) = (loop lo*lo2)
if (m_util.re.is_loop(args[0], a, lo, hi) && f->get_num_parameters() == 1) {
result = m_util.re.mk_loop(a, f->get_parameter(0).get_int() * lo);
return BR_REWRITE1;
}
// (loop (loop a lo) lo2 ..) = (loop lo*lo2)
if (m_util.re.is_loop(args[0], a, lo)) {
SASSERT(f->get_num_parameters() >= 1);
result = m_util.re.mk_loop(a, f->get_parameter(0).get_int() * lo);
return BR_REWRITE1;
}
// (loop a 0 0) = ""
if (f->get_num_parameters() == 2 && f->get_parameter(1).get_int() == 0) {
result = m_util.re.mk_to_re(m_util.str.mk_empty(m_util.re.to_seq(m().get_sort(args[0]))));
return BR_DONE;
}
// (loop a 1 1) = a
if (f->get_num_parameters() == 2 && f->get_parameter(0).get_int() == 1 && f->get_parameter(1).get_int() == 1) {
result = args[0];
return BR_DONE;
}
// (loop a 0) = a*
if (f->get_num_parameters() == 1 && f->get_parameter(0).get_int() == 0) {
result = m_util.re.mk_star(args[0]);
return BR_DONE;
}
break;
case 2:
if (m_autil.is_numeral(args[1], n1) && n1.is_unsigned()) {
result = m_util.re.mk_loop(args[0], n1.get_unsigned());
return BR_DONE;
return BR_REWRITE1;
}
break;
case 3:
if (m_autil.is_numeral(args[1], n1) && n1.is_unsigned() &&
m_autil.is_numeral(args[2], n2) && n2.is_unsigned()) {
m_autil.is_numeral(args[2], n2) && n2.is_unsigned() && n1 <= n2) {
result = m_util.re.mk_loop(args[0], n1.get_unsigned(), n2.get_unsigned());
return BR_DONE;
return BR_REWRITE1;
}
break;
default:

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

@ -133,7 +133,7 @@ class seq_rewriter {
br_status mk_re_star(expr* a, expr_ref& result);
br_status mk_re_plus(expr* a, expr_ref& result);
br_status mk_re_opt(expr* a, expr_ref& result);
br_status mk_re_loop(unsigned num_args, expr* const* args, expr_ref& result);
br_status mk_re_loop(func_decl* f, unsigned num_args, expr* const* args, expr_ref& result);
br_status mk_re_range(expr* lo, expr* hi, expr_ref& result);
bool cannot_contain_prefix(expr* a, expr* b);