only do bitvector analysis when used

Author: Daniel Kroening

src/analyses/goto_check.cpp

@@ -78,7 +78,7 @@ class goto_checkt
 
 protected:
   const namespacet &ns;
-  local_bitvector_analysist *local_bitvector_analysis;
+  std::unique_ptr<local_bitvector_analysist> local_bitvector_analysis;
   goto_programt::const_targett t;
 
   void check_rec(
@@ -1530,8 +1530,9 @@ void goto_checkt::goto_check(
 
   bool did_something = false;
 
-  local_bitvector_analysist local_bitvector_analysis_obj(goto_function);
-  local_bitvector_analysis=&local_bitvector_analysis_obj;
+  if(enable_pointer_check)
+    local_bitvector_analysis = std::unique_ptr<local_bitvector_analysist>(
+      new local_bitvector_analysist(goto_function));
 
   goto_programt &goto_program=goto_function.body;