The preterition or omission of one, some, or all of the compulsory heirs in the direct line, whether living at the time of the execution of the will or born after the death of the testator, shall annul the institution of heir; but the devises and legacies shall be valid insofar as they are not inofficious.
If the omitted compulsory heirs should die before the testator, the institution shall be effectual, without prejudice to the right of representation. (814a)