Simplify initializer to remove byte_update

We introduce byte updates to soundly prepare union initializers, but
such byte updates are not part of the C standard and thus aren't
expected by dump-c. Run simplify to clean them up, when possible.

Author: tautschnig

src/ansi-c/c_typecheck_initializer.cpp

@@ -72,7 +72,10 @@ exprt c_typecheck_baset::do_initializer_rec(
   }
 
   if(value.id()==ID_initializer_list)
-    return do_initializer_list(value, type, force_constant);
+  {
+    return simplify_expr(
+      do_initializer_list(value, type, force_constant), *this);
+  }
 
   if(
     value.id() == ID_array && value.get_bool(ID_C_string_constant) &&

src/ansi-c/expr2c.cpp

@@ -1911,12 +1911,8 @@ std::string expr2ct::convert_constant(
       if(type.subtype().id()!=ID_empty)
         dest="(("+convert(type)+")"+dest+")";
     }
-    else
+    else if(src.operands().size() == 1)
     {
-      // we prefer the annotation
-      if(src.operands().size()!=1)
-        return convert_norep(src, precedence);
-
       const auto &annotation = to_unary_expr(src).op();
 
       if(annotation.id() == ID_constant)
@@ -1933,6 +1929,12 @@ std::string expr2ct::convert_constant(
       else
         return convert_with_precedence(annotation, precedence);
     }
+    else
+    {
+      const auto width = to_pointer_type(type).get_width();
+      mp_integer int_value = bvrep2integer(value, width, false);
+      return "(" + convert(type) + ")" + integer2string(int_value);
+    }
   }
   else if(type.id()==ID_string)
   {