Restore named_sub map entries ordering when reading a goto binary.

Use irept::named_subt::add instead of irept::named_subt::emplace_after
to make sure that entries are sorted by increasing key order.

Author: Remi Delmas

src/util/irep_serialization.cpp

@@ -75,16 +75,12 @@ irept irep_serializationt::read_irep(std::istream &in)
     sub.push_back(reference_convert(in));
   }
 
-#if NAMED_SUB_IS_FORWARD_LIST
-  irept::named_subt::iterator before = named_sub.before_begin();
-#endif
   while(in.peek()=='N')
   {
     in.get();
     irep_idt id = read_string_ref(in);
 #if NAMED_SUB_IS_FORWARD_LIST
-    named_sub.emplace_after(before, id, reference_convert(in));
-    ++before;
+    named_sub.add(id, reference_convert(in));
 #else
     named_sub.emplace(id, reference_convert(in));
 #endif
@@ -95,8 +91,7 @@ irept irep_serializationt::read_irep(std::istream &in)
     in.get();
     irep_idt id = read_string_ref(in);
 #if NAMED_SUB_IS_FORWARD_LIST
-    named_sub.emplace_after(before, id, reference_convert(in));
-    ++before;
+    named_sub.add(id, reference_convert(in));
 #else
     named_sub.emplace(id, reference_convert(in));
 #endif