How to make a OpExpr check compatible among different versions

During one of my works for logical rewrite, I want to check if the expr is
a given Expr.

so the simplest way is:
if (expr->opno == 418 && nodeTag(linitial(expr->args)) == T_xxx &&
nodeTag(lsecond(expr->args)) == T_yyyy )
{
..
}

if we write code like above, we may have issues if the oid changed in the
future version.
so what would be your suggestion?

Thanks