mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-04-13 04:28:17 +00:00
Code Activity
z3/src/ast/rewriter/th_rewriter.cpp
Nikolaj Bjorner 65bfcec146 resurrect rewriting of equality over ite 
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2024-11-22 16:56:08 -08:00

1079 lines
37 KiB
C++
Raw Blame History

/*++
Copyright (c) 2011 Microsoft Corporation
Module Name:
th_rewriter.h
Abstract:
Rewriter for applying all builtin (cheap) theory rewrite rules.
Author:
Leonardo (leonardo) 2011-04-07
Notes:
--*/
#include "params/rewriter_params.hpp"
#include "params/poly_rewriter_params.hpp"
#include "ast/rewriter/th_rewriter.h"
#include "ast/rewriter/bool_rewriter.h"
#include "ast/rewriter/arith_rewriter.h"
#include "ast/rewriter/bv_rewriter.h"
#include "ast/rewriter/char_rewriter.h"
#include "ast/rewriter/datatype_rewriter.h"
#include "ast/rewriter/array_rewriter.h"
#include "ast/rewriter/fpa_rewriter.h"
#include "ast/rewriter/dl_rewriter.h"
#include "ast/rewriter/pb_rewriter.h"
#include "ast/rewriter/recfun_rewriter.h"
#include "ast/rewriter/seq_rewriter.h"
#include "ast/rewriter/rewriter_def.h"
#include "ast/rewriter/var_subst.h"
#include "ast/rewriter/der.h"
#include "ast/rewriter/expr_safe_replace.h"
#include "ast/expr_substitution.h"
#include "ast/ast_smt2_pp.h"
#include "ast/ast_pp.h"
#include "ast/ast_util.h"
#include "ast/well_sorted.h"
#include "ast/for_each_expr.h"
#include "ast/array_peq.h"
namespace {
struct th_rewriter_cfg : public default_rewriter_cfg {
bool_rewriter m_b_rw;
arith_rewriter m_a_rw;
bv_rewriter m_bv_rw;
array_rewriter m_ar_rw;
datatype_rewriter m_dt_rw;
fpa_rewriter m_f_rw;
dl_rewriter m_dl_rw;
pb_rewriter m_pb_rw;
seq_rewriter m_seq_rw;
char_rewriter m_char_rw;
recfun_rewriter m_rec_rw;
arith_util m_a_util;
bv_util m_bv_util;
der m_der;
expr_safe_replace m_rep;
unused_vars_eliminator m_elim_unused_vars;
expr_ref_vector m_pinned;
// substitution support
expr_dependency_ref m_used_dependencies; // set of dependencies of used substitutions
expr_substitution * m_subst = nullptr;
unsigned long long m_max_memory; // in bytes
bool m_new_subst = false;
expr_fast_mark1 m_visited;
expr_mark m_marks;
bool m_new_mark = false;
unsigned m_max_steps = UINT_MAX;
bool m_pull_cheap_ite = true;
bool m_flat = true;
bool m_cache_all = false;
bool m_push_ite_arith = true;
bool m_push_ite_bv = true;
bool m_ignore_patterns_on_ground_qbody = true;
bool m_rewrite_patterns = true;
bool m_enable_der = true;
bool m_nested_der = false;
ast_manager & m() const { return m_b_rw.m(); }
void updt_local_params(params_ref const & _p) {
rewriter_params p(_p);
poly_rewriter_params pp(_p);
m_flat = pp.flat();
m_max_memory = megabytes_to_bytes(p.max_memory());
m_max_steps = p.max_steps();
m_pull_cheap_ite = p.pull_cheap_ite();
m_cache_all = p.cache_all();
m_push_ite_arith = p.push_ite_arith();
m_push_ite_bv = p.push_ite_bv();
m_ignore_patterns_on_ground_qbody = p.ignore_patterns_on_ground_qbody();
m_rewrite_patterns = p.rewrite_patterns();
m_enable_der = p.enable_der();
m_nested_der = _p.get_bool("nested_der", false);
}
void updt_params(params_ref const & p) {
m_b_rw.updt_params(p);
m_a_rw.updt_params(p);
m_bv_rw.updt_params(p);
m_ar_rw.updt_params(p);
m_f_rw.updt_params(p);
m_seq_rw.updt_params(p);
updt_local_params(p);
}
bool flat_assoc(func_decl * f) const {
if (!m_flat) return false;
family_id fid = f->get_family_id();
if (fid == null_family_id)
return false;
decl_kind k = f->get_decl_kind();
if (fid == m_b_rw.get_fid())
return k == OP_AND || k == OP_OR;
if (fid == m_a_rw.get_fid())
return k == OP_ADD;
if (fid == m_bv_rw.get_fid())
return k == OP_BADD || k == OP_BOR || k == OP_BAND || k == OP_BXOR;
return false;
}
bool rewrite_patterns() const { return m_rewrite_patterns; }
bool cache_all_results() const { return m_cache_all; }
bool max_steps_exceeded(unsigned num_steps) const {
if (m_max_memory != SIZE_MAX &&
memory::get_allocation_size() > m_max_memory)
throw rewriter_exception(Z3_MAX_MEMORY_MSG);
return num_steps > m_max_steps;
}
// (iff (= x bit1) A)
// --->
// (= x (ite A bit1 bit0))
br_status apply_tamagotchi(expr * lhs, expr * rhs, expr_ref & result) {
expr * x;
unsigned val;
if (m_bv_rw.is_eq_bit(lhs, x, val)) {
result = m().mk_eq(x, m().mk_ite(rhs, m_bv_rw.mk_numeral(val, 1), m_bv_rw.mk_numeral(1-val, 1)));
return BR_REWRITE2;
}
if (m_bv_rw.is_eq_bit(rhs, x, val)) {
result = m().mk_eq(x, m().mk_ite(lhs, m_bv_rw.mk_numeral(val, 1), m_bv_rw.mk_numeral(1-val, 1)));
return BR_REWRITE2;
}
return BR_FAILED;
}
br_status reduce_app_core(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
family_id fid = f->get_family_id();
if (fid == null_family_id)
return BR_FAILED;
br_status st = BR_FAILED;
if (fid == m_b_rw.get_fid()) {
decl_kind k = f->get_decl_kind();
if (k == OP_EQ) {
// theory dispatch for =
SASSERT(num == 2);
st = reduce_eq(args[0], args[1], result);
if (st != BR_FAILED)
return st;
}
if (k == OP_ITE) {
SASSERT(num == 3);
family_id s_fid = args[1]->get_sort()->get_family_id();
if (s_fid == m_bv_rw.get_fid())
st = m_bv_rw.mk_ite_core(args[0], args[1], args[2], result);
if (st == BR_FAILED && s_fid == m_a_rw.get_fid())
st = m_a_rw.mk_ite_core(args[0], args[1], args[2], result);
CTRACE("th_rewriter_step", st != BR_FAILED, tout << result << "\n");
if (st != BR_FAILED)
return st;
}
if ((k == OP_AND || k == OP_OR) && m_seq_rw.u().has_re()) {
st = m_seq_rw.mk_bool_app(f, num, args, result);
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);
if (st != BR_FAILED)
return st;
}
if (k == OP_DISTINCT && num > 0 && m_bv_rw.is_bv(args[0])) {
st = m_bv_rw.mk_distinct(num, args, result);
if (st != BR_FAILED)
return st;
}
st = m_b_rw.mk_app_core(f, num, args, result);
CTRACE("th_rewriter_step", st != BR_FAILED, tout << result << "\n");
return st;
}
if (fid == m_a_rw.get_fid() && OP_LE == f->get_decl_kind() && m_seq_rw.u().has_seq()) {
st = m_seq_rw.mk_le_core(args[0], args[1], result);
if (st != BR_FAILED)
return st;
}
if (fid == m_a_rw.get_fid() && OP_GE == f->get_decl_kind() && m_seq_rw.u().has_seq()) {
st = m_seq_rw.mk_le_core(args[1], args[0], result);
if (st != BR_FAILED)
return st;
}
if (fid == m_a_rw.get_fid())
return m_a_rw.mk_app_core(f, num, args, result);
if (fid == m_bv_rw.get_fid())
return m_bv_rw.mk_app_core(f, num, args, result);
if (fid == m_ar_rw.get_fid())
return m_ar_rw.mk_app_core(f, num, args, result);
if (fid == m_dt_rw.get_fid())
return m_dt_rw.mk_app_core(f, num, args, result);
if (fid == m_f_rw.get_fid())
return m_f_rw.mk_app_core(f, num, args, result);
if (fid == m_dl_rw.get_fid())
return m_dl_rw.mk_app_core(f, num, args, result);
if (fid == m_pb_rw.get_fid())
return m_pb_rw.mk_app_core(f, num, args, result);
if (fid == m_seq_rw.get_fid())
return m_seq_rw.mk_app_core(f, num, args, result);
if (fid == m_char_rw.get_fid())
return m_char_rw.mk_app_core(f, num, args, result);
if (fid == m_rec_rw.get_fid())
return m_rec_rw.mk_app_core(f, num, args, result);
return BR_FAILED;
}
// auxiliary function for pull_ite_core
expr * mk_eq_value(expr * lhs, expr * value) {
if (m().are_equal(lhs, value)) {
return m().mk_true();
}
else if (m().are_distinct(lhs, value)) {
return m().mk_false();
}
return m().mk_eq(lhs, value);
}
template<bool SWAP>
br_status pull_ite_core(func_decl * p, app * ite, app * value, expr_ref & result) {
if (m().is_eq(p)) {
result = m().mk_ite(ite->get_arg(0),
mk_eq_value(ite->get_arg(1), value),
mk_eq_value(ite->get_arg(2), value));
return BR_REWRITE2;
}
else {
if (SWAP) {
result = m().mk_ite(ite->get_arg(0),
m().mk_app(p, value, ite->get_arg(1)),
m().mk_app(p, value, ite->get_arg(2)));
return BR_REWRITE2;
}
else {
result = m().mk_ite(ite->get_arg(0),
m().mk_app(p, ite->get_arg(1), value),
m().mk_app(p, ite->get_arg(2), value));
return BR_REWRITE2;
}
}
}
// Return true if t is an ite-value-tree form defined as:
// ite-value-tree := (ite c <subtree> <subtree>)
// subtree := value
// | (ite c <subtree> <subtree>)
//
bool is_ite_value_tree(expr * t) {
if (!m().is_ite(t))
return false;
if (t->get_ref_count() != 1)
return false;
ptr_buffer<app> todo;
todo.push_back(to_app(t));
while (!todo.empty()) {
app * ite = todo.back();
todo.pop_back();
expr * arg1 = ite->get_arg(1);
expr * arg2 = ite->get_arg(2);
if (m().is_ite(arg1) && arg1->get_ref_count() == 1) // do not apply on shared terms, since it may blow up
todo.push_back(to_app(arg1));
else if (!m().is_value(arg1))
return false;
if (m().is_ite(arg2) && arg2->get_ref_count() == 1) // do not apply on shared terms, since it may blow up
todo.push_back(to_app(arg2));
else if (!m().is_value(arg2))
return false;
}
return true;
}
br_status pull_ite(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
if (num == 2 && m().is_bool(f->get_range()) && !m().is_bool(args[0])) {
if (m().is_ite(args[0])) {
if (m().is_value(args[1]) && args[0]->get_ref_count() == 1)
return pull_ite_core<false>(f, to_app(args[0]), to_app(args[1]), result);
if (m().is_ite(args[1]) && to_app(args[0])->get_arg(0) == to_app(args[1])->get_arg(0)) {
// (p (ite C A1 B1) (ite C A2 B2)) --> (ite (p A1 A2) (p B1 B2))
result = m().mk_ite(to_app(args[0])->get_arg(0),
m().mk_app(f, to_app(args[0])->get_arg(1), to_app(args[1])->get_arg(1)),
m().mk_app(f, to_app(args[0])->get_arg(2), to_app(args[1])->get_arg(2)));
return BR_REWRITE2;
}
}
if (m().is_ite(args[1]) && m().is_value(args[0]) && args[1]->get_ref_count() == 1)
return pull_ite_core<true>(f, to_app(args[1]), to_app(args[0]), result);
}
family_id fid = f->get_family_id();
if (num == 2 && (fid == m().get_basic_family_id())) {
// (f v3 (ite c v1 v2)) --> (ite v (f v3 v1) (f v3 v2))
if (m().is_value(args[0]) && is_ite_value_tree(args[1]))
return pull_ite_core<true>(f, to_app(args[1]), to_app(args[0]), result);
// (f (ite c v1 v2) v3) --> (ite v (f v1 v3) (f v2 v3))
if (m().is_value(args[1]) && is_ite_value_tree(args[0]))
return pull_ite_core<false>(f, to_app(args[0]), to_app(args[1]), result);
}
return BR_FAILED;
}
br_status pull_ite(expr_ref & result) {
expr * t = result.get();
if (is_app(t)) {
br_status st = pull_ite(to_app(t)->get_decl(), to_app(t)->get_num_args(), to_app(t)->get_args(), result);
if (st != BR_FAILED)
return st;
}
return BR_DONE;
}
bool is_arith_bv_app(expr * t) const {
if (!is_app(t))
return false;
family_id fid = to_app(t)->get_family_id();
return ((fid == m_a_rw.get_fid() && m_push_ite_arith) ||
(fid == m_bv_rw.get_fid() && m_push_ite_bv));
}
bool get_neutral_elem(app * t, expr_ref & n) {
family_id fid = t->get_family_id();
if (fid == m_a_rw.get_fid()) {
switch (t->get_decl_kind()) {
case OP_ADD: n = m_a_util.mk_numeral(rational::zero(), t->get_sort()); return true;
case OP_MUL: n = m_a_util.mk_numeral(rational::one(), t->get_sort()); return true;
default:
return false;
}
}
if (fid == m_bv_rw.get_fid()) {
switch (t->get_decl_kind()) {
case OP_BADD: n = m_bv_util.mk_numeral(rational::zero(), t->get_sort()); return true;
case OP_BMUL: n = m_bv_util.mk_numeral(rational::one(), t->get_sort()); return true;
default:
return false;
}
}
return false;
}
/**
\brief Try to "unify" t1 and t2
Examples
(+ 2 a) (+ 3 a) --> 2, 3, a
(+ 2 a) a --> 2, 0, a
...
*/
bool unify_core(app * t1, expr * t2, expr_ref & new_t1, expr_ref & new_t2, expr_ref & c, bool & first) {
if (t1->get_num_args() != 2)
return false;
expr * a1 = t1->get_arg(0);
expr * b1 = t1->get_arg(1);
if (t2 == b1) {
if (get_neutral_elem(t1, new_t2)) {
new_t1 = a1;
c = b1;
first = false;
return true;
}
}
else if (t2 == a1) {
if (get_neutral_elem(t1, new_t2)) {
new_t1 = b1;
c = a1;
first = true;
return true;
}
}
else if (is_app_of(t2, t1->get_decl()) && to_app(t2)->get_num_args() == 2) {
expr * a2 = to_app(t2)->get_arg(0);
expr * b2 = to_app(t2)->get_arg(1);
if (b1 == b2) {
new_t1 = a1;
new_t2 = a2;
c = b2;
first = false;
return true;
}
if (a1 == a2) {
new_t1 = b1;
new_t2 = b2;
c = a1;
first = true;
return true;
}
if (t1->get_decl()->is_commutative()) {
if (a1 == b2) {
new_t1 = b1;
new_t2 = a2;
c = a1;
first = true; // doesn't really matter for commutative ops.
return true;
}
if (b1 == a2) {
new_t1 = a1;
new_t2 = b2;
c = b1;
first = false; // doesn't really matter for commutative ops.
return true;
}
}
}
return false;
}
// Return true if t1 and t2 are of the form:
// t + a1*x1 + ... + an*xn
// t' + a1*x1 + ... + an*xn
// Store t in new_t1, t' in new_t2 and (a1*x1 + ... + an*xn) in c.
bool unify_add(app * t1, expr * t2, expr_ref & new_t1, expr_ref & new_t2, expr_ref & c) {
unsigned num1 = t1->get_num_args();
expr * const * ms1 = t1->get_args();
if (num1 < 2)
return false;
unsigned num2;
expr * const * ms2;
if (m_a_util.is_add(t2)) {
num2 = to_app(t2)->get_num_args();
ms2 = to_app(t2)->get_args();
}
else {
num2 = 1;
ms2 = &t2;
}
if (num1 != num2 && num1 != num2 + 1 && num1 != num2 - 1)
return false;
new_t1 = nullptr;
new_t2 = nullptr;
expr_fast_mark1 visited1;
expr_fast_mark2 visited2;
for (unsigned i = 0; i < num1; i++) {
expr * arg = ms1[i];
visited1.mark(arg);
}
for (unsigned i = 0; i < num2; i++) {
expr * arg = ms2[i];
visited2.mark(arg);
if (visited1.is_marked(arg))
continue;
if (new_t2)
return false; // more than one missing term
new_t2 = arg;
}
for (unsigned i = 0; i < num1; i++) {
expr * arg = ms1[i];
if (visited2.is_marked(arg))
continue;
if (new_t1)
return false; // more than one missing term
new_t1 = arg;
}
// terms matched...
bool is_int = m_a_util.is_int(t1);
if (!new_t1)
new_t1 = m_a_util.mk_numeral(rational::zero(), is_int);
if (!new_t2)
new_t2 = m_a_util.mk_numeral(rational::zero(), is_int);
// mk common part
ptr_buffer<expr> args;
for (unsigned i = 0; i < num1; i++) {
expr * arg = ms1[i];
if (arg == new_t1.get())
continue;
args.push_back(arg);
}
SASSERT(!args.empty());
if (args.size() == 1)
c = args[0];
else
c = m_a_util.mk_add(args.size(), args.data());
return true;
}
bool unify(expr * t1, expr * t2, func_decl * & f, expr_ref & new_t1, expr_ref & new_t2, expr_ref & c, bool & first) {
#if 0
// Did not work for ring benchmarks
// Hack for handling more complex cases of + apps
// such as (+ 2 t1 t2 t3) and (+ 3 t3 t2 t1)
if (m_a_util.is_add(t1)) {
first = true; // doesn't matter for AC ops
f = to_app(t1)->get_decl();
if (unify_add(to_app(t1), t2, new_t1, new_t2, c))
return true;
}
if (m_a_util.is_add(t2)) {
first = true; // doesn't matter for AC ops
f = to_app(t2)->get_decl();
if (unify_add(to_app(t2), t1, new_t2, new_t1, c))
return true;
}
#endif
if (is_arith_bv_app(t1)) {
f = to_app(t1)->get_decl();
return unify_core(to_app(t1), t2, new_t1, new_t2, c, first);
}
else if (is_arith_bv_app(t2)) {
f = to_app(t2)->get_decl();
return unify_core(to_app(t2), t1, new_t2, new_t1, c, first);
}
else {
return false;
}
}
// Apply transformations of the form
//
// (ite c (+ k1 a) (+ k2 a)) --> (+ (ite c k1 k2) a)
// (ite c (* k1 a) (* k2 a)) --> (* (ite c k1 k2) a)
//
// These transformations are useful for bit-vector problems, since
// they will minimize the number of adders/multipliers/etc
br_status push_ite(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
if (!m().is_ite(f))
return BR_FAILED;
expr * c = args[0];
expr * t = args[1];
expr * e = args[2];
func_decl * f_prime = nullptr;
expr_ref new_t(m()), new_e(m()), common(m());
bool first;
TRACE("push_ite", tout << "unifying:\n" << mk_ismt2_pp(t, m()) << "\n" << mk_ismt2_pp(e, m()) << "\n";);
if (unify(t, e, f_prime, new_t, new_e, common, first)) {
if (first)
result = m().mk_app(f_prime, common, m().mk_ite(c, new_t, new_e));
else
result = m().mk_app(f_prime, m().mk_ite(c, new_t, new_e), common);
TRACE("push_ite", tout << result << "\n";);
return BR_DONE;
}
TRACE("push_ite", tout << "failed\n";);
return BR_FAILED;
}
br_status push_ite(expr_ref & result) {
expr * t = result.get();
if (m().is_ite(t)) {
br_status st = push_ite(to_app(t)->get_decl(), to_app(t)->get_num_args(), to_app(t)->get_args(), result);
if (st != BR_FAILED)
return st;
}
return BR_DONE;
}
void count_down_subterm_references(expr * e, map<expr *, unsigned, ptr_hash<expr>, ptr_eq<expr>> & reference_map) {
if (is_app(e)) {
app * a = to_app(e);
for (unsigned i = 0; i < a->get_num_args(); ++i) {
expr * child = a->get_arg(i);
unsigned countdown = reference_map.get(child, child->get_ref_count()) - 1;
reference_map.insert(child, countdown);
if (countdown == 0)
count_down_subterm_references(child, reference_map);
}
}
}
void log_rewrite_axiom_instantiation(func_decl * f, unsigned num, expr * const * args, expr_ref & result) {
family_id fid = f->get_family_id();
if (fid == m_b_rw.get_fid()) {
decl_kind k = f->get_decl_kind();
if (k == OP_EQ) {
SASSERT(num == 2);
fid = args[0]->get_sort()->get_family_id();
}
else if (k == OP_ITE) {
SASSERT(num == 3);
fid = args[1]->get_sort()->get_family_id();
}
}
app_ref tmp(m());
tmp = m().mk_app(f, num, args);
m().trace_stream() << "[inst-discovered] theory-solving " << static_cast<void *>(nullptr) << " " << m().get_family_name(fid) << "# ; #" << tmp->get_id() << "\n";
tmp = m().mk_eq(tmp, result);
m().trace_stream() << "[instance] " << static_cast<void *>(nullptr) << " #" << tmp->get_id() << "\n";
// Make sure that both the result term and equality were newly introduced.
if (tmp->get_ref_count() == 1) {
if (result->get_ref_count() == 1) {
map<expr *, unsigned, ptr_hash<expr>, ptr_eq<expr>> reference_map;
count_down_subterm_references(result, reference_map);
// Any term that was newly introduced by the rewrite step is only referenced within / reachable from the result term.
for (auto const& kv : reference_map) {
if (kv.m_value == 0) {
m().trace_stream() << "[attach-enode] #" << kv.m_key->get_id() << " 0\n";
}
}
m().trace_stream() << "[attach-enode] #" << result->get_id() << " 0\n";
}
m().trace_stream() << "[attach-enode] #" << tmp->get_id() << " 0\n";
}
m().trace_stream() << "[end-of-instance]\n";
m().trace_stream().flush();
}
br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
result_pr = nullptr;
br_status st = reduce_app_core(f, num, args, result);
if (st != BR_FAILED && m().has_trace_stream()) {
log_rewrite_axiom_instantiation(f, num, args, result);
}
if (st != BR_DONE && st != BR_FAILED) {
CTRACE("th_rewriter_step", st != BR_FAILED,
tout << f->get_name() << "\n";
for (unsigned i = 0; i < num; i++) tout << mk_ismt2_pp(args[i], m()) << "\n";
tout << "---------->\n" << mk_ismt2_pp(result, m()) << "\n";);
return st;
}
if (m_push_ite_bv || m_push_ite_arith) {
if (st == BR_FAILED)
st = push_ite(f, num, args, result);
else
st = push_ite(result);
}
if (m_pull_cheap_ite) {
if (st == BR_FAILED)
st = pull_ite(f, num, args, result);
else
st = pull_ite(result);
}
if (st == BR_FAILED && f->get_family_id() == null_family_id && is_partial_eq(f)) {
st = m_ar_rw.mk_app_core(f, num, args, result);
}
CTRACE("th_rewriter_step", st != BR_FAILED,
tout << f->get_name() << "\n";
for (unsigned i = 0; i < num; i++) tout << mk_ismt2_pp(args[i], m()) << "\n";
tout << "---------->\n" << mk_ismt2_pp(result, m()) << "\n";);
return st;
}
expr_ref mk_app(func_decl* f, unsigned num_args, expr* const* args) {
expr_ref result(m());
proof_ref pr(m());
if (BR_FAILED == reduce_app(f, num_args, args, result, pr))
result = m().mk_app(f, num_args, args);
return result;
}
br_status reduce_eq(expr* a, expr* b, expr_ref& result) {
family_id s_fid = a->get_sort()->get_family_id();
br_status st = BR_FAILED;
if (s_fid == m_a_rw.get_fid())
st = m_a_rw.mk_eq_core(a, b, result);
else if (s_fid == m_bv_rw.get_fid())
st = m_bv_rw.mk_eq_core(a, b, result);
else if (s_fid == m_dt_rw.get_fid())
st = m_dt_rw.mk_eq_core(a, b, result);
else if (s_fid == m_f_rw.get_fid())
st = m_f_rw.mk_eq_core(a, b, result);
else if (s_fid == m_ar_rw.get_fid())
st = m_ar_rw.mk_eq_core(a, b, result);
else if (s_fid == m_seq_rw.get_fid())
st = m_seq_rw.mk_eq_core(a, b, result);
if (st != BR_FAILED)
return st;
st = extended_bv_eq(a, b, result);
if (st != BR_FAILED)
return st;
return apply_tamagotchi(a, b, result);
}
br_status extended_bv_eq(expr* a, expr* b, expr_ref& result) {
if (m_bv_util.is_bv2int(a) || m_bv_util.is_bv2int(b))
return m_bv_rw.mk_eq_bv2int(a, b, result);
return BR_FAILED;
}
expr_ref mk_eq(expr* a, expr* b) {
expr_ref result(m());
br_status st = reduce_eq(a, b, result);
if (BR_FAILED == st)
st = m_b_rw.mk_eq_core(a, b, result);
if (BR_FAILED == st)
result = m().mk_eq(a, b);
return result;
}
/**
* Apply substitution on pattern expressions.
* It happens only very rarely that this operation has an effect.
* To avoid expensive calls to expr_safe_replace we check with a pre-filter
* whether the substitution possibly could apply.
*/
void apply_subst(ptr_buffer<expr>& patterns) {
if (!m_subst)
return;
if (patterns.empty())
return;
if (m_subst->sub().empty())
return;
if (m_new_mark) {
m_marks.reset();
for (auto const& [k, v] : m_subst->sub())
m_marks.mark(k);
m_new_mark = false;
}
struct has_mark {
expr_mark& m_marks;
bool found = false;
has_mark(expr_mark& m) : m_marks(m) {}
void operator()(quantifier* q) {
found = true;
}
void operator()(expr* e) {
found |= m_marks.is_marked(e);
}
};
has_mark has_mark(m_marks);
for (expr* p : patterns)
quick_for_each_expr(has_mark, m_visited, p);
m_visited.reset();
if (!has_mark.found)
return;
if (m_new_subst) {
m_rep.reset();
for (auto const& kv : m_subst->sub())
m_rep.insert(kv.m_key, kv.m_value);
m_new_subst = false;
}
expr_ref tmp(m());
for (unsigned i = 0; i < patterns.size(); ++i) {
m_rep(patterns[i], tmp);
m_pinned.push_back(tmp);
patterns[i] = tmp;
}
}
bool reduce_quantifier(quantifier * old_q,
expr * new_body,
expr * const * new_patterns,
expr * const * new_no_patterns,
expr_ref & result,
proof_ref & result_pr) {
quantifier_ref q1(m());
proof_ref p1(m());
if (is_quantifier(new_body) &&
to_quantifier(new_body)->get_kind() == old_q->get_kind() &&
to_quantifier(new_body)->get_kind() != lambda_k &&
!old_q->has_patterns() &&
!to_quantifier(new_body)->has_patterns()) {
quantifier * nested_q = to_quantifier(new_body);
ptr_buffer<sort> sorts;
buffer<symbol> names;
sorts.append(old_q->get_num_decls(), old_q->get_decl_sorts());
names.append(old_q->get_num_decls(), old_q->get_decl_names());
sorts.append(nested_q->get_num_decls(), nested_q->get_decl_sorts());
names.append(nested_q->get_num_decls(), nested_q->get_decl_names());
q1 = m().mk_quantifier(old_q->get_kind(),
sorts.size(),
sorts.data(),
names.data(),
nested_q->get_expr(),
std::min(old_q->get_weight(), nested_q->get_weight()),
old_q->get_qid(),
old_q->get_skid(),
0, nullptr, 0, nullptr);
SASSERT(is_well_sorted(m(), q1));
if (m().proofs_enabled()) {
p1 = m().mk_pull_quant(old_q, q1);
}
}
else if (old_q->get_kind() == lambda_k &&
is_ground(new_body)) {
result = m_ar_rw.util().mk_const_array(old_q->get_sort(), new_body);
if (m().proofs_enabled()) {
result_pr = m().mk_rewrite(old_q, result);
}
return true;
}
else {
ptr_buffer<expr> new_patterns_buf;
ptr_buffer<expr> new_no_patterns_buf;
new_patterns_buf.append(old_q->get_num_patterns(), new_patterns);
new_no_patterns_buf.append(old_q->get_num_no_patterns(), new_no_patterns);
remove_duplicates(new_patterns_buf);
remove_duplicates(new_no_patterns_buf);
apply_subst(new_patterns_buf);
q1 = m().update_quantifier(old_q,
new_patterns_buf.size(), new_patterns_buf.data(), new_no_patterns_buf.size(), new_no_patterns_buf.data(),
new_body);
m_pinned.reset();
TRACE("reduce_quantifier", tout << mk_ismt2_pp(old_q, m()) << "\n----->\n" << mk_ismt2_pp(q1, m()) << "\n";);
SASSERT(is_well_sorted(m(), q1));
if (m().proofs_enabled() && q1 != old_q) {
p1 = m().mk_rewrite(old_q, q1);
}
}
SASSERT(old_q->get_sort() == q1->get_sort());
result = m_elim_unused_vars(q1);
result_pr = nullptr;
if (m().proofs_enabled()) {
proof_ref p2(m());
if (q1.get() != result.get() && q1->get_kind() != lambda_k)
p2 = m().mk_elim_unused_vars(q1, result);
result_pr = m().mk_transitivity(p1, p2);
}
TRACE("reduce_quantifier", tout << "after elim_unused_vars:\n" << result << " " << result_pr << "\n" ;);
proof_ref p2(m());
expr_ref r(m());
bool der_change = false;
if (m_enable_der && is_quantifier(result) && to_quantifier(result)->get_num_patterns() == 0) {
m_der(to_quantifier(result), r, p2);
der_change = result.get() != r.get();
if (m().proofs_enabled() && der_change)
result_pr = m().mk_transitivity(result_pr, p2);
result = r;
}
if (der_change && !m_nested_der) {
th_rewriter rw(m());
params_ref p;
p.set_bool("nested_der", true);
rw.updt_params(p);
rw(result, r, p2);
if (m().proofs_enabled() && result.get() != r.get())
result_pr = m().mk_transitivity(result_pr, p2);
result = r;
}
SASSERT(old_q->get_sort() == result->get_sort());
return true;
}
th_rewriter_cfg(ast_manager & m, params_ref const & p):
m_b_rw(m, p),
m_a_rw(m, p),
m_bv_rw(m, p),
m_ar_rw(m, p),
m_dt_rw(m),
m_f_rw(m, p),
m_dl_rw(m),
m_pb_rw(m),
m_seq_rw(m, p),
m_char_rw(m),
m_rec_rw(m),
m_a_util(m),
m_bv_util(m),
m_der(m),
m_rep(m),
m_elim_unused_vars(m, params_ref()),
m_pinned(m),
m_used_dependencies(m) {
updt_local_params(p);
}
void set_substitution(expr_substitution * s) {
reset();
m_subst = s;
m_new_subst = true;
m_new_mark = true;
}
void reset() {
m_subst = nullptr;
}
bool get_subst(expr * s, expr * & t, proof * & pr) {
if (m_subst == nullptr)
return false;
expr_dependency * d = nullptr;
if (m_subst->find(s, t, pr, d)) {
m_used_dependencies = m().mk_join(m_used_dependencies, d);
return true;
}
return false;
}
};
}
struct th_rewriter::imp : public rewriter_tpl<th_rewriter_cfg> {
th_rewriter_cfg m_cfg;
imp(ast_manager & m, params_ref const & p):
rewriter_tpl<th_rewriter_cfg>(m, m.proofs_enabled(), m_cfg),
m_cfg(m, p) {
}
expr_ref mk_app(func_decl* f, unsigned sz, expr* const* args) {
return m_cfg.mk_app(f, sz, args);
}
expr_ref mk_eq(expr* a, expr* b) {
return m_cfg.mk_eq(a, b);
}
void set_solver(expr_solver* solver) {
m_cfg.m_seq_rw.set_solver(solver);
}
};
th_rewriter::th_rewriter(ast_manager & m, params_ref const & p):
m_params(p) {
m_imp = alloc(imp, m, p);
}
ast_manager & th_rewriter::m() const {
return m_imp->m();
}
void th_rewriter::updt_params(params_ref const & p) {
m_params.append(p);
m_imp->cfg().updt_params(m_params);
}
void th_rewriter::get_param_descrs(param_descrs & r) {
bool_rewriter::get_param_descrs(r);
arith_rewriter::get_param_descrs(r);
bv_rewriter::get_param_descrs(r);
array_rewriter::get_param_descrs(r);
rewriter_params::collect_param_descrs(r);
}
void th_rewriter::set_flat_and_or(bool f) {
m_imp->cfg().m_b_rw.set_flat_and_or(f);
}
void th_rewriter::set_order_eq(bool f) {
m_imp->cfg().m_b_rw.set_order_eq(f);
}
th_rewriter::~th_rewriter() {
dealloc(m_imp);
}
unsigned th_rewriter::get_cache_size() const {
return m_imp->get_cache_size();
}
unsigned th_rewriter::get_num_steps() const {
return m_imp->get_num_steps();
}
void th_rewriter::cleanup() {
ast_manager & m = m_imp->m();
m_imp->~imp();
new (m_imp) imp(m, m_params);
}
void th_rewriter::reset() {
m_imp->reset();
m_imp->cfg().reset();
}
void th_rewriter::operator()(expr_ref & term) {
expr_ref result(term.get_manager());
try {
m_imp->operator()(term, result);
term = std::move(result);
}
catch (...) {
if (!term.get_manager().inc())
return;
throw;
}
}
void th_rewriter::operator()(expr * t, expr_ref & result) {
try {
m_imp->operator()(t, result);
}
catch (...) {
result = t;
if (!result.get_manager().inc())
return;
throw;
}
}
void th_rewriter::operator()(expr * t, expr_ref & result, proof_ref & result_pr) {
try {
m_imp->operator()(t, result, result_pr);
}
catch (...) {
result = t;
result_pr = nullptr;
if (!result.get_manager().inc())
return;
throw;
}
}
expr_ref th_rewriter::operator()(expr * n, unsigned num_bindings, expr * const * bindings) {
return m_imp->operator()(n, num_bindings, bindings);
}
void th_rewriter::set_substitution(expr_substitution * s) {
m_imp->reset(); // reset the cache
m_imp->cfg().set_substitution(s);
}
expr_dependency * th_rewriter::get_used_dependencies() {
return m_imp->cfg().m_used_dependencies;
}
void th_rewriter::reset_used_dependencies() {
if (get_used_dependencies() != nullptr) {
set_substitution(m_imp->cfg().m_subst); // reset cache preserving subst
m_imp->cfg().m_used_dependencies = nullptr;
}
}
expr_ref th_rewriter::mk_app(func_decl* f, unsigned num_args, expr* const* args) {
return m_imp->mk_app(f, num_args, args);
}
expr_ref th_rewriter::mk_eq(expr* a, expr* b) {
return m_imp->mk_eq(a, b);
}
void th_rewriter::set_solver(expr_solver* solver) {
m_imp->set_solver(solver);
}
bool th_rewriter::reduce_quantifier(quantifier * old_q,
expr * new_body,
expr * const * new_patterns,
expr * const * new_no_patterns,
expr_ref & result,
proof_ref & result_pr) {
return m_imp->cfg().reduce_quantifier(old_q, new_body, new_patterns, new_no_patterns, result, result_pr);
}
View git blame Copy permalink