add recfun rewriting, remove quantifier based recfun

src/ast/ast.cpp

@@ -1379,7 +1379,6 @@ ast_manager::ast_manager(proof_gen_mode m, char const * trace_file, bool is_form
     m_proof_mode(m),
     m_trace_stream(nullptr),
     m_trace_stream_owner(false),
-    m_rec_fun(":rec-fun"),
     m_lambda_def(":lambda-def") {
 
     if (trace_file) {
@@ -1403,7 +1402,6 @@ ast_manager::ast_manager(proof_gen_mode m, std::fstream * trace_stream, bool is_
     m_proof_mode(m),
     m_trace_stream(trace_stream),
     m_trace_stream_owner(false),
-    m_rec_fun(":rec-fun"),
     m_lambda_def(":lambda-def") {
 
     if (!is_format_manager)
@@ -1421,7 +1419,6 @@ ast_manager::ast_manager(ast_manager const & src, bool disable_proofs):
     m_proof_mode(disable_proofs ? PGM_DISABLED : src.m_proof_mode),
     m_trace_stream(src.m_trace_stream),
     m_trace_stream_owner(false),
-    m_rec_fun(":rec-fun"),
     m_lambda_def(":lambda-def") {
     SASSERT(!src.is_format_manager());
     m_format_manager = alloc(ast_manager, PGM_DISABLED, m_trace_stream, true);
@@ -1756,13 +1753,6 @@ quantifier* ast_manager::is_lambda_def(func_decl* f) {
     return nullptr;
 }
 
-
-func_decl* ast_manager::get_rec_fun_decl(quantifier* q) const {
-    SASSERT(is_rec_fun_def(q)); 
-    return to_app(to_app(q->get_pattern(0))->get_arg(0))->get_decl(); 
-}
-
-
 void ast_manager::register_plugin(family_id id, decl_plugin * plugin) {
     SASSERT(m_plugins.get(id, 0) == 0);
     m_plugins.setx(id, plugin, 0);

src/ast/ast.h

@@ -1553,7 +1553,6 @@ protected:
     bool slow_not_contains(ast const * n);
 #endif
     ast_manager *             m_format_manager; // hack for isolating format objects in a different manager.
-    symbol                    m_rec_fun;
     symbol                    m_lambda_def;
 
     void init();
@@ -1666,13 +1665,10 @@ public:
 
     bool contains(ast * a) const { return m_ast_table.contains(a); }
     
-    bool is_rec_fun_def(quantifier* q) const { return q->get_qid() == m_rec_fun; }
     bool is_lambda_def(quantifier* q) const { return q->get_qid() == m_lambda_def; }
     void add_lambda_def(func_decl* f, quantifier* q);
     quantifier* is_lambda_def(func_decl* f);
-    func_decl* get_rec_fun_decl(quantifier* q) const;
     
-    symbol const& rec_fun_qid() const { return m_rec_fun; }
 
     symbol const& lambda_def_qid() const { return m_lambda_def; }
 

src/ast/recfun_decl_plugin.h

@@ -220,6 +220,7 @@ namespace recfun {
         ~util();
 
         ast_manager & m() { return m_manager; }
+        family_id get_family_id() const { return m_fid; }
         decl::plugin& get_plugin() { return *m_plugin; }
 
         bool is_case_pred(expr * e) const { return is_app_of(e, m_fid, OP_FUN_CASE_PRED); }

src/ast/rewriter/CMakeLists.txt

@@ -29,6 +29,7 @@ z3_add_component(rewriter
     pb2bv_rewriter.cpp
     push_app_ite.cpp
     quant_hoist.cpp
+    recfun_rewriter.cpp
     rewriter.cpp
     seq_rewriter.cpp
     th_rewriter.cpp

src/ast/rewriter/recfun_rewriter.cpp

@@ -0,0 +1,39 @@
+/*++
+Copyright (c) 2018 Microsoft Corporation
+
+Module Name:
+
+    recfun_rewriter.cpp
+
+Abstract:
+
+    Rewriter recursive function applications to values
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2020-04-26
+
+
+--*/
+
+
+#include "ast/rewriter/recfun_rewriter.h"
+#include "ast/rewriter/var_subst.h"
+    
+br_status recfun_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result) {
+    if (m_rec.is_defined(f)) {
+        for (unsigned i = 0; i < num_args; ++i) {
+            if (!m.is_value(args[i]))
+                return BR_FAILED;
+        }
+        recfun::def const& d = m_rec.get_def(f);
+        var_subst sub(m);
+        result = sub(d.get_rhs(), num_args, args);
+        return BR_REWRITE_FULL;
+    }
+    else {
+        return BR_FAILED;
+    }
+}
+
+

src/ast/rewriter/recfun_rewriter.h

@@ -0,0 +1,36 @@
+/*++
+Copyright (c) 2018 Microsoft Corporation
+
+Module Name:
+
+    recfun_rewriter.h
+
+Abstract:
+
+    Rewriter recursive function applications to values
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2020-04-26
+
+
+--*/
+
+#pragma once
+
+#include "ast/recfun_decl_plugin.h"
+#include "ast/rewriter/rewriter.h"
+
+class recfun_rewriter {
+    ast_manager& m;
+    recfun::util  m_rec;
+public:
+    recfun_rewriter(ast_manager& m): m(m), m_rec(m) {}
+    ~recfun_rewriter() {}
+    
+    br_status mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result);
+
+    family_id get_fid() const { return m_rec.get_family_id(); }
+
+};
+

src/ast/rewriter/th_rewriter.cpp

@@ -26,6 +26,7 @@ Notes:
 #include "ast/rewriter/fpa_rewriter.h"
 #include "ast/rewriter/dl_rewriter.h"
 #include "ast/rewriter/pb_rewriter.h"
+#include "ast/rewriter/recfun_rewriter.h"
 #include "ast/rewriter/seq_rewriter.h"
 #include "ast/rewriter/rewriter_def.h"
 #include "ast/rewriter/var_subst.h"
@@ -46,6 +47,7 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
     dl_rewriter         m_dl_rw;
     pb_rewriter         m_pb_rw;
     seq_rewriter        m_seq_rw;
+    recfun_rewriter     m_rec_rw;
     arith_util          m_a_util;
     bv_util             m_bv_util;
     unsigned long long  m_max_memory; // in bytes
@@ -219,6 +221,8 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
             return m_pb_rw.mk_app_core(f, num, args, result);
         if (fid == m_seq_rw.get_fid())
             return m_seq_rw.mk_app_core(f, num, args, result);
+        if (fid == m_rec_rw.get_fid())
+            return m_rec_rw.mk_app_core(f, num, args, result);
         return BR_FAILED;
     }
 
@@ -747,6 +751,7 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
         m_dl_rw(m),
         m_pb_rw(m),
         m_seq_rw(m),
+        m_rec_rw(m),
         m_a_util(m),
         m_bv_util(m),
         m_used_dependencies(m),