make card2bv a simplifier

src/ast/simplifiers/CMakeLists.txt

@@ -1,6 +1,7 @@
 z3_add_component(simplifiers
   SOURCES
     bv_slice.cpp
+    card2bv.cpp
     elim_unconstrained.cpp
     eliminate_predicates.cpp
     euf_completion.cpp

src/ast/simplifiers/card2bv.cpp

@@ -0,0 +1,61 @@
+/*++
+Copyright (c) 2022 Microsoft Corporation
+
+Module Name:
+
+    card2bv.cpp
+
+Abstract:
+
+    convert cardinality constraints to bit-vectors
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2022-11-24
+
+--*/
+
+
+#include "ast/simplifiers/card2bv.h"
+#include "ast/rewriter/th_rewriter.h"
+#include "ast/rewriter/pb2bv_rewriter.h"
+
+card2bv::card2bv(ast_manager& m, params_ref const& p, dependent_expr_state& fmls) :
+    dependent_expr_simplifier(m, fmls), m_params(p) {}
+
+void card2bv::reduce() {
+    th_rewriter rw1(m, m_params);
+    pb2bv_rewriter rw2(m, m_params);
+                        
+    expr_ref new_f1(m), new_f2(m);
+    proof_ref new_pr(m);
+    for (unsigned idx = 0; !m_fmls.inconsistent() && idx < m_fmls.size(); idx++) {
+        auto [f, d] = m_fmls[idx]();
+        rw1(f, new_f1);        
+        rw2(false, new_f1, new_f2, new_pr);        
+        if (new_f2 != f) {
+            TRACE("card2bv", tout << "Rewriting " << new_f1 << "\n" << new_f2 << "\n");
+            m_fmls.update(idx, dependent_expr(m, new_f2, d));
+            ++m_stats.m_num_rewrites;
+        }
+    }
+    
+    expr_ref_vector fmls(m);
+    rw2.flush_side_constraints(fmls);
+    for (expr* e : fmls)
+        m_fmls.add(dependent_expr(m, e, nullptr));
+
+    func_decl_ref_vector const& fns = rw2.fresh_constants();
+    for (func_decl* f : fns)
+        m_fmls.model_trail().hide(f);    
+}
+
+void card2bv::collect_statistics(statistics& st) const {
+    st.update("card2bv-rewrites", m_stats.m_num_rewrites);
+}
+
+void card2bv::collect_param_descrs(param_descrs& r) {
+    r.insert("keep_cardinality_constraints", CPK_BOOL, "(default: true) retain cardinality constraints for solver");
+    pb2bv_rewriter rw(m, m_params);
+    rw.collect_param_descrs(r);
+}

src/ast/simplifiers/card2bv.h

@@ -0,0 +1,42 @@
+/*++
+Copyright (c) 2022 Microsoft Corporation
+
+Module Name:
+
+    card2bv.h
+
+Abstract:
+
+    convert cardinality constraints to bit-vectors
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2022-11-24
+
+
+--*/
+
+#pragma once
+
+#include "ast/simplifiers/dependent_expr_state.h"
+#include "ast/rewriter/th_rewriter.h"
+
+
+class card2bv : public dependent_expr_simplifier {
+
+    struct stats {
+        unsigned m_num_rewrites = 0;
+        void reset() { memset(this, 0, sizeof(*this)); }
+    };
+
+    stats                  m_stats;
+    params_ref             m_params;
+
+public:
+    card2bv(ast_manager& m, params_ref const& p, dependent_expr_state& fmls);
+    void reduce() override;
+    void collect_statistics(statistics& st) const override;
+    void reset_statistics() override { m_stats.reset(); }
+    void updt_params(params_ref const& p) override { m_params.append(p); }
+    void collect_param_descrs(param_descrs& r) override;
+};

src/ast/simplifiers/elim_unconstrained.cpp

@@ -285,7 +285,7 @@ void elim_unconstrained::update_model_trail(generic_model_converter& mc, vector<
     for (auto const& entry : mc.entries()) {
         switch (entry.m_instruction) {
         case generic_model_converter::instruction::HIDE:
-            trail.push(entry.m_f);
+            trail.hide(entry.m_f);
             break;
         case generic_model_converter::instruction::ADD:
             break;

src/ast/simplifiers/eliminate_predicates.cpp

@@ -327,7 +327,7 @@ void eliminate_predicates::try_find_macro(clause& cl) {
         app_ref def(m), k(m), fml(m);
         func_decl_ref fn(m);
         fn = m.mk_fresh_func_decl(df->get_arity(), df->get_domain(), df->get_range());
-        m_fmls.model_trail().push(fn); // hide definition of fn
+        m_fmls.model_trail().hide(fn); // hide definition of fn
         k = m.mk_app(fn, f->get_num_args(), f->get_args());        
         def = m.mk_ite(cond, t, k);
         insert_macro(f, def, cl.m_dep);

src/ast/simplifiers/model_reconstruction_trail.h

@@ -102,7 +102,7 @@ public:
     /**
     * add declaration to hide
     */
-    void push(func_decl* f) {
+    void hide(func_decl* f) {
         m_trail.push_back(alloc(entry, m, f));
         m_trail_stack.push(push_back_vector(m_trail));
     }