We do have an internal compiler flag that can disable adding “const restrict” to read-only data, however it’s not something we’ve exposed publicly. I can’t post this flag on our forums but would be willing to have PGI Customer Support (trs@pgroup.com) send it to you if you drop them a note.
Do you have a use case where disabling textured memory helps? I might be able to convince folks here to expose the flag if we have justification.