[Bug middle-end/70828] New: broken array-type subarrays inside acc data in openacc

["cesar at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70828

            Bug ID: 70828
           Summary: broken array-type subarrays inside acc data in openacc
           Product: gcc
           Version: 6.1.0
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: cesar at gcc dot gnu.org
          Reporter: cesar at gcc dot gnu.org
                CC: tschwinge at gcc dot gnu.org
  Target Milestone: ---

Created attachment 38351
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38351&action=edit
broken subarray

Given an array-typed subarray with a non-zero base element on an acc data
construct, the gimplifier will implicitly add a pcopy clause for any parallel
and kernels construct which uses that array. The pcopy is correct, but this
pcopy expects the entire array to be present on the accelerator. This
ultimately results in a runtime failure when the base of the subarray is not
element zero.

This problem can be reproduced with the attached test case in trunk and gcc-6.