if expr1 has sideeffects. This can't be done safely even in case of
    short boolean evaluation, because expr1 may return the inverse the
    second time its called (and "0 or 1" is not the same as "0", and
    neither is "1 and 0"), based on comment by Michael Karcher
  * perform a full string compare when comparing stringconstnodes
    before the string constant labels have been generated (patch by
    Michael Karcher, mantis #21255)

git-svn-id: trunk@20485 -