MarsSeed [1] filed a deletion request for isl14 [2]:

This legacy version from 7+ years ago seems not needed anymore. Only cloog-isl14 depends on it, but that is not used by anything. (Submitted deletion request for that.)

So in order to ease maintenance burden, I recommend to delete this as well, if there are no objections.

(Also, the main isl package has been adopted from AUR to Arch [core] under the name 'libisl'. So all isl* packages on AUR should either be renamed in accordance, or deleted if not used.)

[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/isl14/