https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119474
--- Comment #6 from Andrew Stubbs <ams at gcc dot gnu.org> --- The address space has to be introduced "late" because it's done in the accelerator compiler, so post-IPA. The pass is "oaccdevlow" (currently no.103). The address space is selected via the TARGET_GOACC_ADJUST_PRIVATE_DECL hook.