Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/pull_ite_tree.h

@@ -0,0 +1,101 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    pull_ite_tree.h
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-06-22.
+
+Revision History:
+
+--*/
+#ifndef _PULL_ITE_TREE_H_
+#define _PULL_ITE_TREE_H_
+
+#include"ast.h"
+#include"simplifier.h"
+#include"recurse_expr.h"
+#include"obj_hashtable.h"
+#include"expr_map.h"
+
+/**
+   \brief Functor for applying the following transformation
+   F[(p (ite c t1 t2) args)] = F'[(ite c t1 t2), p, args]
+
+   F'[(ite c t1 t2), p, args] = (ite c F'[t1, p, args] F'[t2, p, args])
+   F'[t, p, args] = (p t args)
+*/
+class pull_ite_tree {
+    ast_manager &         m_manager;
+    simplifier &          m_simplifier;
+    func_decl *           m_p;
+    ptr_vector<expr>      m_args;
+    unsigned              m_arg_idx; //!< position of the ite argument
+    expr_map              m_cache;
+    ptr_vector<expr>      m_todo;
+
+    bool is_cached(expr * n) const { return m_cache.contains(n); }
+    void get_cached(expr * n, expr * & r, proof * & p) const { m_cache.get(n, r, p); }
+    void cache_result(expr * n, expr * r, proof * pr);
+    void visit(expr * n, bool & visited);
+    bool visit_children(expr * n);
+    void reduce(expr * n);
+    /**
+       \brief Creante an application (m_p ... n ...) where n is the argument m_arg_idx and the other arguments
+       are in m_args.
+    */
+    expr * mk_p_arg(expr * n) {
+        m_args[m_arg_idx] = n;
+        return m_manager.mk_app(m_p, m_args.size(), m_args.c_ptr());
+    }
+public:
+    pull_ite_tree(ast_manager & m, simplifier & s);
+    /**
+       \brief Apply the transformation above if n contains an ite-expression.
+       Store the result in r. If n does not contain an ite-expression, then
+       store n in r.
+
+       When proof generation is enabled, pr is a proof for n = r.
+    */
+    void operator()(app * n, app_ref & r, proof_ref & pr);
+};
+
+/**
+   \brief Functor for applying the pull_ite_tree on subexpressions n that
+   satisfy the is_target virtual predicate.
+*/
+class pull_ite_tree_star : public simplifier {
+protected:
+    pull_ite_tree m_proc;
+    virtual bool get_subst(expr * n, expr_ref & r, proof_ref & p);
+public:
+    pull_ite_tree_star(ast_manager & m, simplifier & s);
+    virtual ~pull_ite_tree_star() { release_plugins(); }
+    virtual bool is_target(app * n) const = 0;
+};
+
+/**
+   \brief Apply pull_ite_tree on predicates of the form
+   (p ite v) and (p v ite)
+
+   where:
+   - p is an interpreted predicate
+   - ite is an ite-term expression
+   - v is a value
+*/
+class pull_cheap_ite_tree_star : public pull_ite_tree_star {
+public:
+    pull_cheap_ite_tree_star(ast_manager & m, simplifier & s):pull_ite_tree_star(m, s) {}
+    virtual ~pull_cheap_ite_tree_star() {}
+    virtual bool is_target(app * n) const;
+};
+
+#endif /* _PULL_ITE_TREE_H_ */
+