make card2bv a simplifier

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);
+}