[Bug libgomp/92503] New: [OpenACC] Behavior of 'acc_free' if the memory space is still used in a mapping

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92503

            Bug ID: 92503
           Summary: [OpenACC] Behavior of 'acc_free' if the memory space
                    is still used in a mapping
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: libgomp
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: jakub at gcc dot gnu.org, jules at gcc dot gnu.org
  Target Milestone: ---

Currently, we state ('libgomp/oacc-mem.c:acc_free') that: "OpenACC 2.0a
(3.2.16) doesn't specify what to do in the event the device address is mapped.
We choose to check if it mapped, and if it is, to unmap it."

(That is, 'acc_free' looks up 'acc_hostptr', and if found, then does an
implicit 'acc_unmap_data' on that, and only then frees the memory space.)

This, seems counter-intuitive for me.  I'm not aware of "free" functions
generally first cleaning up any usage of the respective memory space, which
isn't even possible in the general case.