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more on #3858 elim_term_ite

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-04-09 10:31:21 -07:00
parent 21b7dc627e
commit cc794a19bc
2 changed files with 46 additions and 32 deletions
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4
src/ast/rewriter/var_subst.h
View file

@ -49,6 +49,8 @@ public:
Otherwise, (VAR 0) is stored in the first position, (VAR 1) in the second, and so on.
*/
expr_ref operator()(expr * n, unsigned num_args, expr * const * args);
inline expr_ref operator()(expr * n, expr_ref_vector const& args) { return (*this)(n, args.size(), args.c_ptr()); }
inline expr_ref operator()(expr * n, ptr_vector<expr> const& args) { return (*this)(n, args.size(), args.c_ptr()); }
void reset() { m_reducer.reset(); }
};
@ -90,6 +92,8 @@ class expr_free_vars {
ptr_vector<sort> m_sorts;
ptr_vector<expr> m_todo;
public:
expr_free_vars() {}
expr_free_vars(expr* e) { (*this)(e); }
void reset();
void operator()(expr* e);
void accumulate(expr* e);

74
src/muz/transforms/dl_mk_elim_term_ite.cpp
View file

@ -17,27 +17,32 @@ Revision History:
--*/
#include "muz/transforms/dl_mk_elim_term_ite.h"
#include "tactic/core/blast_term_ite_tactic.h"
#include "ast/ast_util.h"
#include "ast/expr_abstract.h"
#include "tactic/core/blast_term_ite_tactic.h"
#include "tactic/tactic.h"
#include "tactic/core/elim_term_ite_tactic.h"
#include "muz/transforms/dl_mk_elim_term_ite.h"
namespace {
/**
* collect uninterpreted constants that are contained in ground
*/
struct uninterp_const_collector {
app_ref_vector &m_consts;
uninterp_const_collector(app_ref_vector &v) : m_consts(v) {}
app_ref_vector& m_consts;
expr_ref_vector const& m_ground;
uninterp_const_collector(app_ref_vector &v, expr_ref_vector const& g) : m_consts(v), m_ground(g) {}
void operator()(var *v) {}
void operator()(quantifier *n) {}
void operator()(expr *a){}
void operator()(app *a){
if (is_uninterp_const(a)) {m_consts.push_back(a);};
if (is_uninterp_const(a) && m_ground.contains(a))
m_consts.push_back(a);
}
};
void collect_uninterp_consts(expr *e, app_ref_vector &v) {
uninterp_const_collector c(v);
void collect_uninterp_consts(expr *e, app_ref_vector &v, expr_ref_vector const& g) {
uninterp_const_collector c(v, g);
quick_for_each_expr(c, e);
}
@ -47,9 +52,9 @@ namespace {
term_ite_proc(ast_manager &m) : m(m) {}
void operator()(var *v) {}
void operator()(quantifier *n) {}
void operator()(expr *a){}
void operator()(app *a){
if (m.is_term_ite(a)) throw found();
void operator()(expr *a) {
if (m.is_term_ite(a))
throw found();
}
};
@ -57,14 +62,16 @@ namespace {
term_ite_proc f(m);
try {
quick_for_each_expr(f, e);
} catch (const term_ite_proc::found &) {
}
catch (const term_ite_proc::found &) {
return true;
}
return false;
}
bool has_term_ite(expr_ref &e) { return has_term_ite(e, e.m());}
bool has_term_ite(expr_ref &e) { return has_term_ite(e, e.m());}
}
namespace datalog {
mk_elim_term_ite::mk_elim_term_ite(context & ctx, unsigned priority) :
rule_transformer::plugin(priority, false),
@ -75,18 +82,23 @@ namespace datalog {
mk_elim_term_ite::~mk_elim_term_ite() {}
/**
\brief map free variables in e to ground, fresh, constants
m_ground is reset on every new rule so it is safe to assume
that the sorts in m_ground are consistent.
*/
expr_ref mk_elim_term_ite::ground(expr* e) {
expr_free_vars fv;
fv(e);
if (m_ground.size() < fv.size())
m_ground.resize(fv.size());
expr_free_vars fv(e);
m_ground.reserve(fv.size());
for (unsigned i = 0, sz = fv.size(); i < sz; ++i) {
if (fv[i] && !m_ground.get(i))
if (!fv[i])
continue;
if (!m_ground.get(i))
m_ground[i] = m.mk_fresh_const("c", fv[i]);
SASSERT(m.get_sort(m_ground.get(i)) == fv[i]);
}
var_subst vsub(m, false);
return vsub(e, m_ground.size(), m_ground.c_ptr());
return vsub(e, m_ground);
}
bool mk_elim_term_ite::elim(rule &r, rule_set &new_rules){
@ -96,13 +108,12 @@ namespace datalog {
unsigned utsz = r.get_uninterpreted_tail_size();
unsigned tsz = r.get_tail_size();
expr_ref_vector new_conjs(m);
expr_ref tmp(m);
for (unsigned i = utsz; i < tsz; ++i)
new_conjs.push_back(r.get_tail(i));
flatten_and(new_conjs);
expr_ref fml1(m), fml2(m), body(m), head(m);
expr_ref fml1(m), fml2(m), body(m);
// blast ite
body = mk_and(new_conjs);
@ -127,12 +138,11 @@ namespace datalog {
rule_ref new_rule(rm.mk(r.get_head(), tail.size(), tail.c_ptr(), nullptr, r.name(), false), rm);
rm.mk_rule_rewrite_proof(r, *new_rule.get());
new_rules.add_rule(new_rule);
TRACE("dl_term_ite", tout << "No term-ite after blast_term_ite\n";);
TRACE("dl", tout << "No term-ite after blast_term_ite\n";);
return true;
}
TRACE("dl_term_ite",
tout << "Rule has term-ite after blasting, starting elimination\n";);
TRACE("dl", tout << "Rule has term-ite after blasting, starting elimination\n";);
body = ground(body);
// elim ite
tactic_ref elim_term_ite = mk_elim_term_ite_tactic(m);
@ -145,6 +155,7 @@ namespace datalog {
unsigned sz = g->num_exprs();
(*elim_term_ite)(g, result);
if (result.size() == 1) {
// NSB code review: fragile test for effect
goal_ref new_goal = result[0];
if (new_goal->num_exprs() != sz) {
new_conjs.reset();
@ -160,20 +171,20 @@ namespace datalog {
body = mk_and(new_conjs);
rw(body);
head = ground(r.get_head());
fml2 = m.mk_implies(body, head);
fml2 = m.mk_implies(body, ground(r.get_head()));
if (has_term_ite(fml2))
return false;
app_ref_vector consts(m);
collect_uninterp_consts(fml2, consts);
collect_uninterp_consts(fml2, consts, m_ground);
fml2 = mk_forall(m, consts.size(), consts.c_ptr(), fml2);
proof_ref p(m);
rm.mk_rule(fml2, p, new_rules, r.name());
// TBD: breaks abstraction barrier: mk_rule could convert a single formula
// NSB code review: breaks abstraction barrier: mk_rule could convert a single formula
// into multiple rules
rm.mk_rule_rewrite_proof(r, *new_rules.last());
TRACE("dl_term_ite", tout << "New rule: " << fml2 << "\n";);
TRACE("dl", tout << "New rule: " << fml2 << "\n";);
return true;
}
@ -188,8 +199,7 @@ namespace datalog {
bool change = false;
for (auto *rule : source) {
if (m_ctx.canceled()) {
change = false;
break;
return nullptr;
}
change |= elim(*rule, *rules);
}