new rewriter

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

src/ast/rewriter/hoist_rewriter.h

@@ -0,0 +1,80 @@
+/*++
+Copyright (c) 2019 Microsoft Corporation
+
+Module Name:
+
+    hoist_rewriter.h
+
+Abstract:
+
+    Hoist predicates over disjunctions
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2019-2-4
+
+Notes:
+
+--*/
+#ifndef HOIST_REWRITER_H_
+#define HOIST_REWRITER_H_
+
+#include "ast/ast.h"
+#include "ast/rewriter/rewriter.h"
+#include "util/params.h"
+#include "util/union_find.h"
+#include "util/obj_hashtable.h"
+
+class hoist_rewriter {
+    ast_manager &  m_manager;
+    expr_ref_vector                 m_args;
+    obj_hashtable<expr>             m_preds1, m_preds2;
+    basic_union_find                m_uf1, m_uf2, m_uf0;
+    ptr_vector<expr>                m_es;
+    svector<std::pair<expr*,expr*>> m_eqs;
+    u_map<expr*>                    m_roots;
+    obj_map<expr, unsigned> m_expr2var;
+    ptr_vector<expr>        m_var2expr;
+    expr_mark               m_mark;
+
+    br_status mk_or(unsigned num_args, expr * const * args, expr_ref & result);
+
+    bool is_and(expr* e);
+
+    bool is_var(expr* e) { return m_expr2var.contains(e); }
+    expr* mk_expr(unsigned v) { return m_var2expr[v]; }
+    unsigned mk_var(expr* e);
+
+    void reset(basic_union_find& uf);
+
+public:
+    hoist_rewriter(ast_manager & m, params_ref const & p = params_ref());
+    ast_manager& m() const { return m_manager; }
+    family_id get_fid() const { return m().get_basic_family_id(); }
+    bool is_eq(expr * t) const { return m().is_eq(t); }       
+    void updt_params(params_ref const & p) {}
+    static void get_param_descrs(param_descrs & r) {}
+    br_status mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result);    
+};
+
+struct hoist_rewriter_cfg : public default_rewriter_cfg {
+    hoist_rewriter m_r;
+    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) {
+        result_pr = nullptr;
+        if (f->get_family_id() != m_r.get_fid())
+            return BR_FAILED;
+        return m_r.mk_app_core(f, num, args, result);
+    }
+    hoist_rewriter_cfg(ast_manager & m, params_ref const & p):m_r(m, p) {}
+};
+
+class hoist_rewriter_star : public rewriter_tpl<hoist_rewriter_cfg> {
+    hoist_rewriter_cfg m_cfg;
+public:
+    hoist_rewriter_star(ast_manager & m, params_ref const & p = params_ref()):
+        rewriter_tpl<hoist_rewriter_cfg>(m, false, m_cfg),
+        m_cfg(m, p) {}
+};
+
+#endif