[Bug c/50459] alignof doesn't work on plain old constant, works with expressions containing it

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50459

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Created attachment 32594
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32594&action=edit
pr50459

Yeah.  This is regtested patch that covers even other attributes.  If this
approach is ok then I can take this bug & post to ML.