mising files

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/ast/rewriter/maximize_ac_sharing.h

@@ -0,0 +1,125 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    maximize_ac_sharing.h
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-10-22.
+
+Revision History:
+
+--*/
+#ifndef MAXIMIZE_AC_SHARING_H_
+#define MAXIMIZE_AC_SHARING_H_
+
+#include "util/hashtable.h"
+#include "util/region.h"
+#include "ast/bv_decl_plugin.h"
+#include "ast/rewriter/rewriter.h"
+
+/**
+   \brief Functor used to maximize the amount of shared terms in an expression.
+   The idea is to rewrite AC terms to maximize sharing.
+   Example:
+
+   (f (bvadd a (bvadd b c)) (bvadd a (bvadd b d)))
+
+   is rewritten to:
+
+   (f (bvadd (bvadd a b) c) (bvadd (bvadd a b) d))
+
+   \warning This class uses an opportunistic heuristic to maximize sharing.
+   There is no guarantee that the optimal expression will be produced.
+*/
+class maximize_ac_sharing : public default_rewriter_cfg {
+    
+    struct entry {
+        func_decl * m_decl;
+        expr *      m_arg1;
+        expr *      m_arg2;
+
+        entry(func_decl * d = 0, expr * arg1 = 0, expr * arg2 = 0):m_decl(d), m_arg1(arg1), m_arg2(arg2) {
+            SASSERT((d == 0 && arg1 == 0 && arg2 == 0) || (d != 0 && arg1 != 0 && arg2 != 0));
+            if (arg1->get_id() > arg2->get_id())
+                std::swap(m_arg1, m_arg2);
+        }
+
+        unsigned hash() const {
+            unsigned a = m_decl->get_id();
+            unsigned b = m_arg1->get_id();
+            unsigned c = m_arg2->get_id();
+            mix(a,b,c);
+            return c;
+        }
+
+        bool operator==(entry const & e) const {
+            return m_decl == e.m_decl && m_arg1 == e.m_arg1 && m_arg2 == e.m_arg2;
+        }
+    };
+
+    typedef ptr_hashtable<entry, obj_ptr_hash<entry>, deref_eq<entry> > cache;
+
+protected:
+    void register_kind(decl_kind k);
+
+private:
+    ast_manager &     m;
+    bool              m_init;
+    region            m_region;
+    cache             m_cache;
+    ptr_vector<entry> m_entries;
+    unsigned_vector   m_scopes;
+    svector<decl_kind>    m_kinds; //!< kinds to be processed
+
+    bool contains(func_decl * f, expr * arg1, expr * arg2);
+    void insert(func_decl * f, expr * arg1, expr * arg2);
+    void restore_entries(unsigned old_lim);
+    void init() {
+        if (!m_init) {
+            init_core();
+            m_init = true;
+        }
+    }
+protected:
+    virtual void init_core() = 0; 
+    virtual bool is_numeral(expr * n) const = 0;
+public:
+    maximize_ac_sharing(ast_manager & m);
+    virtual ~maximize_ac_sharing();
+    void push_scope();
+    void pop_scope(unsigned num_scopes);
+    void reset();
+    br_status reduce_app(func_decl* f, unsigned n, expr * const* args, expr_ref& result, proof_ref& result_pr);
+
+};
+
+class maximize_bv_sharing : public maximize_ac_sharing {
+    bv_util m_util;
+protected:
+    virtual void init_core();
+    virtual bool is_numeral(expr * n) const;
+public:
+    maximize_bv_sharing(ast_manager & m);
+};
+
+class maximize_bv_sharing_rw : public rewriter_tpl<maximize_bv_sharing> {
+    maximize_bv_sharing m_cfg;
+public:
+    maximize_bv_sharing_rw(ast_manager& m):
+        rewriter_tpl<maximize_bv_sharing>(m, m.proofs_enabled(), m_cfg),
+        m_cfg(m)
+    {} 
+    void push_scope() { m_cfg.push_scope(); }
+    void pop_scope(unsigned n) { m_cfg.pop_scope(n); }
+    void reset() { m_cfg.reset(); }
+};
+
+#endif /* MAXIMIZE_AC_SHARING_H_ */
+