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Merge pull request #8780 from Z3Prover/copilot/convert-blast-term-ite-to-simplifier

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Convert `blast-term-ite` tactic to a `dependent_expr_simplifier`
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Nikolaj Bjorner 2026-02-26 15:51:30 -08:00 • committed by GitHub
commit c70f902b53
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4 changed files with 152 additions and 200 deletions
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1
src/ast/simplifiers/CMakeLists.txt
View file

@ -33,6 +33,7 @@ z3_add_component(simplifiers
TACTIC_HEADERS
bit_blaster.h
bit2int.h
blast_term_ite_simplifier.h
elim_bounds.h
elim_term_ite.h
pull_nested_quantifiers.h

138
src/ast/simplifiers/blast_term_ite_simplifier.h Normal file
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@ -0,0 +1,138 @@
/*++
Copyright (c) 2013 Microsoft Corporation
Module Name:
blast_term_ite_simplifier.h
Author:
Nikolaj Bjorner (nbjorner) 2013-11-4
--*/
#pragma once
#include "ast/simplifiers/dependent_expr_state.h"
#include "ast/rewriter/rewriter_def.h"
#include "ast/scoped_proof.h"
#include "params/tactic_params.hpp"
class blast_term_ite_simplifier : public dependent_expr_simplifier {
struct rw_cfg : public default_rewriter_cfg {
ast_manager& m;
unsigned m_num_fresh;
unsigned m_max_steps;
unsigned m_max_inflation;
unsigned m_init_term_size;
rw_cfg(ast_manager& _m, params_ref const& p):
m(_m),
m_num_fresh(0),
m_max_steps(UINT_MAX),
m_max_inflation(UINT_MAX),
m_init_term_size(0) {
updt_params(p);
}
void updt_params(params_ref const& p) {
tactic_params tp(p);
m_max_steps = p.get_uint("max_steps", tp.blast_term_ite_max_steps());
m_max_inflation = p.get_uint("max_inflation", tp.blast_term_ite_max_inflation());
}
bool max_steps_exceeded(unsigned num_steps) const {
return num_steps >= m_max_steps;
}
br_status mk_app_core(func_decl* f, unsigned num_args, expr* const* args, expr_ref& result) {
if (m.is_ite(f))
return BR_FAILED;
if (m_max_inflation < UINT_MAX &&
m_init_term_size > 0 &&
m_max_inflation * m_init_term_size < m_num_fresh)
return BR_FAILED;
for (unsigned i = 0; i < num_args; ++i) {
expr* c, *t, *e;
if (!m.is_bool(args[i]) && m.is_ite(args[i], c, t, e)) {
TRACE(blast_term_ite, result = m.mk_app(f, num_args, args); tout << result << "\n";);
expr_ref e1(m), e2(m);
ptr_vector<expr> args1(num_args, args);
args1[i] = t;
e1 = m.mk_app(f, num_args, args1.data());
if (m.are_equal(t, e)) {
result = e1;
return BR_REWRITE1;
}
else {
args1[i] = e;
e2 = m.mk_app(f, num_args, args1.data());
result = m.mk_ite(c, e1, e2);
++m_num_fresh;
return BR_REWRITE3;
}
}
}
return BR_FAILED;
}
bool rewrite_patterns() const { return false; }
br_status reduce_app(func_decl* f, unsigned num, expr* const* args, expr_ref& result, proof_ref& result_pr) {
return mk_app_core(f, num, args, result);
}
};
struct rw : public rewriter_tpl<rw_cfg> {
rw_cfg m_cfg;
rw(ast_manager& m, params_ref const& p):
rewriter_tpl<rw_cfg>(m, m.proofs_enabled(), m_cfg),
m_cfg(m, p) {
}
};
rw m_rw;
public:
blast_term_ite_simplifier(ast_manager& m, params_ref const& p, dependent_expr_state& s):
dependent_expr_simplifier(m, s), m_rw(m, p) {}
char const* name() const override { return "blast-term-ite"; }
void reduce() override {
expr_ref new_fml(m);
proof_ref new_pr(m);
for (unsigned idx : indices()) {
auto const& d = m_fmls[idx];
if (m_rw.m_cfg.m_max_inflation < UINT_MAX) {
m_rw.m_cfg.m_init_term_size = get_num_exprs(d.fml());
m_rw.m_cfg.m_num_fresh = 0;
}
m_rw(d.fml(), new_fml, new_pr);
if (d.fml() != new_fml)
m_fmls.update(idx, dependent_expr(m, new_fml, mp(d.pr(), new_pr), d.dep()));
}
}
static void blast_term_ite(expr_ref& fml, unsigned max_inflation) {
ast_manager& m = fml.get_manager();
scoped_no_proof _sp(m);
params_ref p;
rw ite_rw(m, p);
ite_rw.m_cfg.m_max_inflation = max_inflation;
if (max_inflation < UINT_MAX)
ite_rw.m_cfg.m_init_term_size = get_num_exprs(fml);
try {
expr_ref tmp(m);
ite_rw(fml, tmp);
fml = tmp;
}
catch (z3_exception &) {
// max steps exceeded.
}
}
};

200
src/tactic/core/blast_term_ite_tactic.cpp
View file

@ -14,203 +14,9 @@ Author:
Nikolaj Bjorner (nbjorner) 2013-11-4
--*/
#include "ast/normal_forms/defined_names.h"
#include "ast/rewriter/rewriter_def.h"
#include "ast/scoped_proof.h"
#include "tactic/tactical.h"
#include "params/tactic_params.hpp"
//
// (f (if c1 (if c2 e1 e2) e3) b c) ->
// (if c1 (if c2 (f e1 b c)
//
class blast_term_ite_tactic : public tactic {
struct rw_cfg : public default_rewriter_cfg {
ast_manager& m;
unsigned long long m_max_memory; // in bytes
unsigned m_num_fresh; // number of expansions
unsigned m_max_steps;
unsigned m_max_inflation;
unsigned m_init_term_size;
rw_cfg(ast_manager & _m, params_ref const & p):
m(_m),
m_num_fresh(0),
m_max_steps(UINT_MAX),
m_max_inflation(UINT_MAX),
m_init_term_size(0) {
updt_params(p);
}
void updt_params(params_ref const & p) {
tactic_params tp(p);
m_max_memory = megabytes_to_bytes(p.get_uint("max_memory", UINT_MAX));
m_max_steps = p.get_uint("max_steps", tp.blast_term_ite_max_steps());
m_max_inflation = p.get_uint("max_inflation", tp.blast_term_ite_max_inflation()); // multiplicative factor of initial term size.
}
bool max_steps_exceeded(unsigned num_steps) const {
// if (memory::get_allocation_size() > m_max_memory)
// throw tactic_exception(TACTIC_MAX_MEMORY_MSG);
return num_steps >= m_max_steps;
}
br_status mk_app_core(func_decl* f, unsigned num_args, expr* const* args, expr_ref& result) {
if (m.is_ite(f)) {
return BR_FAILED;
}
if (m_max_inflation < UINT_MAX &&
m_init_term_size > 0 &&
m_max_inflation * m_init_term_size < m_num_fresh)
return BR_FAILED;
for (unsigned i = 0; i < num_args; ++i) {
expr* c, *t, *e;
if (!m.is_bool(args[i]) && m.is_ite(args[i], c, t, e)) {
TRACE(blast_term_ite, result = m.mk_app(f, num_args, args); tout << result << "\n";);
expr_ref e1(m), e2(m);
ptr_vector<expr> args1(num_args, args);
args1[i] = t;
e1 = m.mk_app(f, num_args, args1.data());
if (m.are_equal(t, e)) {
result = e1;
return BR_REWRITE1;
}
else {
args1[i] = e;
e2 = m.mk_app(f, num_args, args1.data());
result = m.mk_ite(c, e1, e2);
++m_num_fresh;
return BR_REWRITE3;
}
}
}
return BR_FAILED;
}
bool rewrite_patterns() const { return false; }
br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, proof_ref & result_pr) {
return mk_app_core(f, num, args, result);
}
};
struct rw : public rewriter_tpl<rw_cfg> {
rw_cfg m_cfg;
rw(ast_manager & m, params_ref const & p):
rewriter_tpl<rw_cfg>(m, m.proofs_enabled(), m_cfg),
m_cfg(m, p) {
}
};
struct imp {
ast_manager & m;
rw m_rw;
imp(ast_manager & _m, params_ref const & p):
m(_m),
m_rw(m, p) {
}
void updt_params(params_ref const & p) {
m_rw.m_cfg.updt_params(p);
}
void operator()(goal_ref const & g, goal_ref_buffer & result) {
tactic_report report("blast-term-ite", *g);
expr_ref new_curr(m);
proof_ref new_pr(m);
unsigned num_fresh = 0;
unsigned idx = 0;
for (auto [curr, dep, pr] : *g) {
if (m_rw.m_cfg.m_max_inflation < UINT_MAX) {
m_rw.m_cfg.m_init_term_size = get_num_exprs(curr);
num_fresh += m_rw.m_cfg.m_num_fresh;
m_rw.m_cfg.m_num_fresh = 0;
}
m_rw(curr, new_curr, new_pr);
new_pr = m.mk_modus_ponens(pr, new_pr);
g->update(idx++, new_curr, new_pr, dep);
}
report_tactic_progress(":blast-term-ite-consts", m_rw.m_cfg.m_num_fresh + num_fresh);
g->inc_depth();
result.push_back(g.get());
}
};
imp * m_imp;
params_ref m_params;
public:
blast_term_ite_tactic(ast_manager & m, params_ref const & p):
m_params(p) {
m_imp = alloc(imp, m, p);
}
tactic * translate(ast_manager & m) override {
return alloc(blast_term_ite_tactic, m, m_params);
}
~blast_term_ite_tactic() override {
dealloc(m_imp);
}
char const* name() const override { return "blast_term_ite"; }
void updt_params(params_ref const & p) override {
m_params.append(p);
m_imp->m_rw.m_cfg.updt_params(m_params);
}
void collect_param_descrs(param_descrs & r) override {
insert_max_memory(r);
insert_max_steps(r);
r.insert("max_inflation", CPK_UINT, "(default: infinity) multiplicative factor of initial term size.", "4294967295");
}
void operator()(goal_ref const & in, goal_ref_buffer & result) override {
(*m_imp)(in, result);
}
void cleanup() override {
ast_manager & m = m_imp->m;
dealloc(m_imp);
m_imp = alloc(imp, m, m_params);
}
static void blast_term_ite(expr_ref& fml, unsigned max_inflation) {
ast_manager& m = fml.get_manager();
scoped_no_proof _sp(m);
params_ref p;
rw ite_rw(m, p);
ite_rw.m_cfg.m_max_inflation = max_inflation;
if (max_inflation < UINT_MAX) {
ite_rw.m_cfg.m_init_term_size = get_num_exprs(fml);
}
try {
expr_ref tmp(m);
ite_rw(fml, tmp);
fml = tmp;
}
catch (z3_exception &) {
// max steps exceeded.
}
}
};
tactic * mk_blast_term_ite_tactic(ast_manager & m, params_ref const & p) {
return clean(alloc(blast_term_ite_tactic, m, p));
}
#include "tactic/core/blast_term_ite_tactic.h"
void blast_term_ite(expr_ref& fml, unsigned max_inflation) {
blast_term_ite_tactic::blast_term_ite(fml, max_inflation);
blast_term_ite_simplifier::blast_term_ite(fml, max_inflation);
}

13
src/tactic/core/blast_term_ite_tactic.h
View file

@ -45,13 +45,20 @@ Use `elim-term-ite` elsewhere when possible.
#pragma once
#include "util/params.h"
class ast_manager;
class tactic;
#include "tactic/tactic.h"
#include "tactic/dependent_expr_state_tactic.h"
#include "ast/simplifiers/blast_term_ite_simplifier.h"
tactic * mk_blast_term_ite_tactic(ast_manager & m, params_ref const & p = params_ref());
inline tactic * mk_blast_term_ite_tactic(ast_manager & m, params_ref const & p = params_ref()) {
return alloc(dependent_expr_state_tactic, m, p,
[](auto& m, auto& p, auto& s) -> dependent_expr_simplifier* {
return alloc(blast_term_ite_simplifier, m, p, s);
});
}
/*
ADD_TACTIC("blast-term-ite", "blast term if-then-else by hoisting them.", "mk_blast_term_ite_tactic(m, p)")
ADD_SIMPLIFIER("blast-term-ite", "blast term if-then-else by hoisting them.", "alloc(blast_term_ite_simplifier, m, p, s)")
*/
void blast_term_ite(expr_ref& fml, unsigned max_inflation);