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add demodulator simplifier

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refactor demodulator-rewriter a bit to separate reusable features.
This commit is contained in:
Nikolaj Bjorner 2022-12-04 09:39:28 -08:00
parent 9acbfa3923
commit 1974c224ab
8 changed files with 624 additions and 155 deletions
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136
src/ast/substitution/demodulator_rewriter.h
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@ -24,6 +24,7 @@ Revision History:
#include "ast/ast.h"
#include "ast/substitution/substitution.h"
#include "ast/rewriter/bool_rewriter.h"
#include "ast/rewriter/th_rewriter.h"
#include "util/obj_hashtable.h"
#include "util/obj_pair_hashtable.h"
#include "util/array_map.h"
@ -92,6 +93,92 @@ The code in spc_rewriter.* does something like that. We cannot reuse this code d
for the superposion engine in Z3, but we can adapt it for our needs in the preprocessor.
*/
class demodulator_util {
ast_manager& m;
int is_subset(expr*, expr*) const;
int is_smaller(expr*, expr*) const;
public:
demodulator_util(ast_manager& m):m(m) {}
bool is_demodulator(expr* e, app_ref& large, expr_ref & small) const;
unsigned max_var_id(expr* e);
unsigned max_var_id(expr_ref_vector const& e);
};
/**
\brief Custom matcher & substitution application
*/
class demodulator_match_subst {
typedef std::pair<expr *, expr *> expr_pair;
typedef obj_pair_hashtable<expr, expr> cache;
void reset();
ast_manager & m;
substitution m_subst;
cache m_cache;
svector<expr_pair> m_todo;
bool m_all_args_eq;
bool match_args(app * t, expr * const * args);
public:
demodulator_match_subst(ast_manager & m);
void reserve(unsigned max_vid) { m_subst.reserve(2, max_vid+1); }
/**
\brief Let f be the top symbol of lhs. If (f args) is an
instance of lhs, that is, there is a substitution s
s.t. s[lhs] = (f args), then return true and store s[rhs]
into new_rhs. Where s[t] represents the application of the
substitution s into t.
Assumptions, the variables in lhs and (f args) are assumed to be distinct.
So, (f x y) matches (f y x).
Moreover, the result should be in terms of the variables in (f args).
*/
bool operator()(app * lhs, expr * rhs, expr * const * args, expr_ref & new_rhs);
/**
\brief Return true if \c i is an instance of \c t.
*/
bool operator()(expr * t, expr * i);
bool can_rewrite(expr* n, expr* lhs);
};
class demodulator_rewriter_util {
ast_manager& m;
std::function<bool(func_decl*, expr_ref_vector const&, expr_ref&)> m_rewrite1;
typedef std::pair<expr *, bool> expr_bool_pair;
class plugin {
ast_manager& m;
public:
plugin(ast_manager& m): m(m) { }
void ins_eh(expr* k, expr_bool_pair v) { m.inc_ref(k); m.inc_ref(v.first); }
void del_eh(expr* k, expr_bool_pair v) { m.dec_ref(k); m.dec_ref(v.first); }
static unsigned to_int(expr const * k) { return k->get_id(); }
};
typedef array_map<expr*, expr_bool_pair, plugin> expr_map;
typedef expr_map rewrite_cache_map;
th_rewriter m_th_rewriter;
expr_ref_buffer m_rewrite_todo;
rewrite_cache_map m_rewrite_cache;
expr_ref_buffer m_new_exprs;
expr_ref_vector m_new_args;
bool rewrite_visit_children(app * a);
void rewrite_cache(expr * e, expr * new_e, bool done);
public:
demodulator_rewriter_util(ast_manager& m);
void set_rewrite1(std::function<bool(func_decl*, expr_ref_vector const&, expr_ref&)>& fn) { m_rewrite1 = fn; }
expr_ref rewrite(expr * n);
};
class demodulator_rewriter final {
class rewrite_proc;
class add_back_idx_proc;
@ -119,47 +206,10 @@ class demodulator_rewriter final {
typedef obj_map<quantifier, app_expr_pair> demodulator2lhs_rhs;
typedef expr_map rewrite_cache_map;
/**
\brief Custom matcher & substitution application
*/
class match_subst {
typedef std::pair<expr *, expr *> expr_pair;
typedef obj_pair_hashtable<expr, expr> cache;
void reset();
ast_manager & m;
substitution m_subst;
cache m_cache;
svector<expr_pair> m_todo;
bool m_all_args_eq;
bool match_args(app * t, expr * const * args);
public:
match_subst(ast_manager & m);
void reserve(unsigned max_vid) { m_subst.reserve(2, max_vid+1); }
/**
\brief Let f be the top symbol of lhs. If (f args) is an
instance of lhs, that is, there is a substitution s
s.t. s[lhs] = (f args), then return true and store s[rhs]
into new_rhs. Where s[t] represents the application of the
substitution s into t.
Assumptions, the variables in lhs and (f args) are assumed to be distinct.
So, (f x y) matches (f y x).
Moreover, the result should be in terms of the variables in (f args).
*/
bool operator()(app * lhs, expr * rhs, expr * const * args, expr_ref & new_rhs);
/**
\brief Return true if \c i is an instance of \c t.
*/
bool operator()(expr * t, expr * i);
};
ast_manager & m;
match_subst m_match_subst;
demodulator_match_subst m_match_subst;
demodulator_util m_util;
bool_rewriter m_bsimp;
fwd_idx_map m_fwd_idx;
back_idx_map m_back_idx;
@ -179,7 +229,6 @@ class demodulator_rewriter final {
void remove_bwd_idx(expr* q);
bool check_fwd_idx_consistency();
void show_fwd_idx(std::ostream & out);
bool is_demodulator(expr * e, app_ref & large, expr_ref & small) const;
bool can_rewrite(expr * n, expr * lhs);
expr * rewrite(expr * n);
@ -188,13 +237,6 @@ class demodulator_rewriter final {
void rewrite_cache(expr * e, expr * new_e, bool done);
void reschedule_processed(func_decl * f);
void reschedule_demodulators(func_decl * f, expr * np);
unsigned max_var_id(expr_ref_vector const& es);
// is_smaller returns -1 for e1<e2, 0 for e1==e2 and +1 for e1>e2.
int is_smaller(expr * e1, expr * e2) const;
// is_subset returns -1 for e1 subset e2, +1 for e2 subset e1, 0 else.
int is_subset(expr * e1, expr * e2) const;
public:
demodulator_rewriter(ast_manager & m);