reduce set of mainly verbose warnings raised by -Wmaybe-uninitialized and unused variable warnings from release mode builds

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

src/muz/base/dl_rule_set.cpp

@@ -601,7 +601,7 @@ namespace datalog {
                 return;
             }
             while (!m_stack_P.empty()) {
-                unsigned on_stack_num;
+                unsigned on_stack_num = 0;
                 VERIFY( m_preorder_nums.find(m_stack_P.back(), on_stack_num) );
                 if (on_stack_num <= p_num) {
                     break;
@@ -710,7 +710,7 @@ namespace datalog {
                 item_set::iterator eend=deps.end();
                 for (; eit!=eend; ++eit) {
                     T * tgt = *eit;
-                    unsigned tgt_comp;
+                    unsigned tgt_comp = 0;
                     VERIFY( m_component_nums.find(tgt, tgt_comp) );
 
                     //m_components[tgt_comp]==0 means the edge is intra-component.

src/muz/ddnf/ddnf.cpp

@@ -836,7 +836,7 @@ namespace datalog {
         }
 
         void compile_eq(expr* e, expr_ref& result, var* v, unsigned hi, unsigned lo, expr* c) {
-            tbv* t;
+            tbv* t = 0;
             // TBD: hi, lo are ignored.
             VERIFY(m_expr2tbv.find(e, t));            
             var_ref w(m);

src/muz/pdr/pdr_context.cpp

@@ -274,7 +274,7 @@ namespace pdr {
 
         for (unsigned i = 0; i < src.size(); ) {
             expr * curr = src[i].get();
-            unsigned stored_lvl;
+            unsigned stored_lvl = 0;
             VERIFY(m_prop2level.find(curr, stored_lvl));
             SASSERT(stored_lvl >= src_level);
             bool assumes_level;

src/muz/pdr/pdr_util.cpp

@@ -247,7 +247,7 @@ namespace pdr {
         }
 
         bool test_eq(expr* e) const {
-            expr* lhs, *rhs;
+            expr* lhs = 0, *rhs = 0;
             VERIFY(m.is_eq(e, lhs, rhs));
             if (!a.is_int_real(lhs)) {
                 return true;

src/muz/rel/dl_compiler.cpp

@@ -466,7 +466,7 @@ namespace datalog {
 
         //used to save on filter_identical instructions where the check is already done 
         //by the join operation
-        unsigned second_tail_arg_ofs;
+        unsigned second_tail_arg_ofs = 0;
 
         // whether to dealloc the previous result
         bool dealloc = true;

src/muz/rel/dl_mk_partial_equiv.cpp

@@ -109,7 +109,7 @@ namespace datalog {
             rule_vector const& rv = *(it->m_value);
             bool has_symmetry = false;
             bool has_transitivity = false;
-            unsigned i_symmetry, i_transitivity;
+            unsigned i_symmetry = 0, i_transitivity = 0;
             family_id kind = rm.get_requested_predicate_kind(p);
             for (unsigned i = 0; i < rv.size(); ++i) {
                 

src/muz/rel/dl_relation_manager.cpp

@@ -277,7 +277,7 @@ namespace datalog {
     relation_plugin & relation_manager::get_relation_plugin(family_id kind) {
         SASSERT(kind>=0);
         SASSERT(kind<m_next_relation_fid);
-        relation_plugin * res;
+        relation_plugin * res = 0;
         VERIFY(m_kind2plugin.find(kind, res));
         return *res;
     }

src/muz/rel/dl_sparse_table.cpp

@@ -327,8 +327,7 @@ namespace datalog {
             key_value key;
             key.resize(key_len);
 
-            offset_vector * index_entry;
-            DEBUG_CODE( index_entry = 0; );
+            offset_vector * index_entry = 0;
             bool key_modified = true;
 
             for (; ofs!=after_last; ofs+=t.m_fact_size) {

src/muz/transforms/dl_mk_loop_counter.cpp

@@ -56,7 +56,7 @@ namespace datalog {
 
     app_ref mk_loop_counter::del_arg(app* fn) {        
         expr_ref_vector args(m);
-        func_decl* old_fn, *new_fn = fn->get_decl();
+        func_decl* old_fn = 0, *new_fn = fn->get_decl();
         SASSERT(fn->get_num_args() > 0);
         args.append(fn->get_num_args()-1, fn->get_args());
         VERIFY (m_new2old.find(new_fn, old_fn));

src/muz/transforms/dl_mk_magic_sets.cpp

@@ -264,7 +264,7 @@ namespace datalog {
         }
 
 
-        func_decl * new_head_pred;
+        func_decl * new_head_pred = 0;
         VERIFY( m_adorned_preds.find(adornment_desc(head->get_decl(), head_adornment), new_head_pred) );
         app * new_head = m.mk_app(new_head_pred, head->get_args());
 

src/muz/transforms/dl_mk_unbound_compressor.cpp

@@ -317,7 +317,6 @@ namespace datalog {
         unsigned tail_index = 0;
         while (tail_index < utail_len) {
             app * t = r->get_tail(tail_index);
-            func_decl * t_pred = t->get_decl();
 
             add_in_progress_indices(arg_indices, t);