z3-z3-4.13.0.src.ast.rewriter.bv_elim.cpp Maven / Gradle / Ivy
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/*++
Copyright (c) 2015 Microsoft Corporation
--*/
#include "ast/rewriter/bv_elim.h"
#include "ast/bv_decl_plugin.h"
#include "ast/rewriter/var_subst.h"
#include "ast/rewriter/rewriter_def.h"
#include
bool bv_elim_cfg::reduce_quantifier(quantifier * q,
expr * body,
expr * const * new_patterns,
expr * const * new_no_patterns,
expr_ref & result,
proof_ref & result_pr) {
svector names, _names;
sort_ref_buffer sorts(m), _sorts(m);
expr_ref_buffer pats(m);
expr_ref_buffer no_pats(m);
expr_ref_buffer subst_map(m), _subst_map(m);
var_subst subst(m);
bv_util bv(m);
expr_ref new_body(m);
expr* old_body = body;
unsigned num_decls = q->get_num_decls();
family_id bfid = m.mk_family_id("bv");
//
// Traverse sequence of bound variables to eliminate
// bit-vecctor variables and replace them by
// Booleans.
//
unsigned var_idx = 0;
bool found = false;
for (unsigned i = num_decls; i > 0; ) {
--i;
sort* s = q->get_decl_sort(i);
symbol nm = q->get_decl_name(i);
if (bv.is_bv_sort(s)) {
// convert n-bit bit-vector variable into sequence of n-Booleans.
unsigned num_bits = bv.get_bv_size(s);
expr_ref_buffer args(m);
expr_ref bv(m);
found = true;
for (unsigned j = 0; j < num_bits; ++j) {
std::ostringstream new_name;
new_name << nm.str();
new_name << '_';
new_name << j;
var* v = m.mk_var(var_idx++, m.mk_bool_sort());
args.push_back(v);
_sorts.push_back(m.mk_bool_sort());
_names.push_back(symbol(new_name.str()));
}
bv = m.mk_app(bfid, OP_MKBV, 0, nullptr, args.size(), args.data());
_subst_map.push_back(bv.get());
}
else {
_subst_map.push_back(m.mk_var(var_idx++, s));
_sorts.push_back(s);
_names.push_back(nm);
}
}
if (!found) {
return false;
}
//
// reverse the vectors.
//
SASSERT(_names.size() == _sorts.size());
for (unsigned i = _names.size(); i > 0; ) {
--i;
names.push_back(_names[i]);
sorts.push_back(_sorts[i]);
}
for (unsigned i = _subst_map.size(); i > 0; ) {
--i;
subst_map.push_back(_subst_map[i]);
}
expr* const* sub = subst_map.data();
unsigned sub_size = subst_map.size();
new_body = subst(old_body, sub_size, sub);
for (unsigned j = 0; j < q->get_num_patterns(); j++) {
pats.push_back(subst(new_patterns[j], sub_size, sub));
}
for (unsigned j = 0; j < q->get_num_no_patterns(); j++) {
no_pats.push_back(subst(new_no_patterns[j], sub_size, sub));
}
result = m.mk_quantifier(forall_k,
names.size(),
sorts.data(),
names.data(),
new_body.get(),
q->get_weight(),
q->get_qid(),
q->get_skid(),
pats.size(), pats.data(),
no_pats.size(), no_pats.data());
result_pr = m.mk_rewrite(q, result);
return true;
}