[Bug middle-end/110639] New: [OpenMP][5.1] Predefined firstprivate for pointers - attachment missing

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110639

            Bug ID: 110639
           Summary: [OpenMP][5.1] Predefined firstprivate for pointers -
                    attachment missing
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: openmp, wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
  Target Milestone: ---

OpenMP 5.1 changed (quoting GCC impl. status):

Pointer predetermined firstprivate getting initialized to address of matching
mapped list item per 5.1, Sect. 2.21.7.2


However, looking at the examples in the OpenMP spec issue #1796 (TRAC864) this
does not handle partially mapped data correctly:

int a[100];
int *p = &a[0];

#pragma omp target teams distribute map(a[start:n])
for (int i = start; i < start+n; i++) {
  p[i] = f(p[i], i);
}

Here, 'p' has an points to 'a' (actually, to the base address of 'a') but this
address is not mapped.  However, it still points to the extended address range
of mapped data.