fixes to bugs exposed by regressions

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

src/ast/rewriter/pb_rewriter.cpp

@@ -0,0 +1,65 @@
+/*++
+Copyright (c) 2013 Microsoft Corporation
+
+Module Name:
+
+    pb_rewriter.cpp
+
+Abstract:
+
+    Basic rewriting rules for PB constraints.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2013-14-12
+
+Notes:
+
+--*/
+
+#include "pb_rewriter.h"
+
+br_status pb_rewriter::mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result) {
+    ast_manager& m = result.get_manager();
+    rational sum(0), maxsum(0);
+    for (unsigned i = 0; i < num_args; ++i) {
+        if (m.is_true(args[i])) {
+            sum += m_util.get_coeff(f, i);
+            maxsum += m_util.get_coeff(f, i);
+        }
+        else if (!m.is_false(args[i])) {
+            maxsum += m_util.get_coeff(f, i);            
+        }
+    }
+    rational k = m_util.get_k(f);
+    
+    switch(f->get_decl_kind()) {
+    case OP_AT_MOST_K:
+    case OP_PB_LE:
+        if (sum > k) {
+            result = m.mk_false();
+            return BR_DONE;
+        }
+        if (maxsum <= k) {
+            result = m.mk_true();
+            return BR_DONE;
+        }
+        return BR_FAILED;
+    case OP_AT_LEAST_K:
+    case OP_PB_GE:
+        if (sum >= k) {
+            result = m.mk_true();
+            return BR_DONE;
+        }
+        if (maxsum < k) {
+            result = m.mk_false();
+            return BR_DONE;
+        }
+        return BR_FAILED;
+    default:
+        UNREACHABLE();
+        return BR_FAILED;
+    }    
+}
+
+

src/ast/rewriter/pb_rewriter.h

@@ -0,0 +1,45 @@
+/*++
+Copyright (c) 2013 Microsoft Corporation
+
+Module Name:
+
+    pb_rewriter.h
+
+Abstract:
+
+    Basic rewriting rules for PB constraints.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2013-14-12
+
+Notes:
+
+--*/
+#ifndef _PB_REWRITER_H_
+#define _PB_REWRITER_H_
+
+#include"pb_decl_plugin.h"
+#include"rewriter_types.h"
+#include"params.h"
+
+/**
+   \brief Cheap rewrite rules for PB constraints
+*/
+class pb_rewriter {
+    pb_util       m_util;
+public:    
+    pb_rewriter(ast_manager & m, params_ref const & p = params_ref()):
+        m_util(m) {
+    }
+    ast_manager & m() const { return m_util.get_manager(); }
+    family_id get_fid() const { return m_util.get_family_id(); }
+
+    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);
+
+};
+
+#endif

src/ast/rewriter/th_rewriter.cpp

@@ -25,6 +25,7 @@ Notes:
 #include"array_rewriter.h"
 #include"float_rewriter.h"
 #include"dl_rewriter.h"
+#include"pb_rewriter.h"
 #include"rewriter_def.h"
 #include"expr_substitution.h"
 #include"ast_smt2_pp.h"
@@ -41,6 +42,7 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
     datatype_rewriter   m_dt_rw;
     float_rewriter      m_f_rw;
     dl_rewriter         m_dl_rw;
+    pb_rewriter         m_pb_rw;
     arith_util          m_a_util;
     bv_util             m_bv_util;
     unsigned long long  m_max_memory; // in bytes
@@ -195,6 +197,8 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
             return m_f_rw.mk_app_core(f, num, args, result);
         if (fid == m_dl_rw.get_fid())
             return m_dl_rw.mk_app_core(f, num, args, result);
+        if (fid == m_pb_rw.get_fid())
+            return m_pb_rw.mk_app_core(f, num, args, result);
         return BR_FAILED;
     }
 
@@ -644,6 +648,7 @@ struct th_rewriter_cfg : public default_rewriter_cfg {
         m_dt_rw(m),
         m_f_rw(m, p),
         m_dl_rw(m),
+        m_pb_rw(m),
         m_a_util(m),
         m_bv_util(m),
         m_used_dependencies(m),