[Bug libgomp/107227] New: Compiler bug in private allocatable array in OpenACC compute statement

[Bug libgomp/107227] New: Compiler bug in private allocatable array in OpenACC compute statement

[shb at gatech dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107227

            Bug ID: 107227
           Summary: Compiler bug in private allocatable array in OpenACC
                    compute statement
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgomp
          Assignee: unassigned at gcc dot gnu.org
          Reporter: shb at gatech dot edu
                CC: jakub at gcc dot gnu.org
  Target Milestone: ---

The program below does not compile (nor does any variant of it involving
allocatable statements that I can think of). 
```
program main
integer :: i
real, allocatable :: arr(:)
allocate(arr(10))
!$acc parallel loop private(arr)
do i=1,10
    arr=1.0
end do
end
```

The error is 
```
!$acc parallel loop private(arr)
      |                                ^
internal compiler error: in expand_oacc_for, at omp-expand.cc:7660
```

A version of this suggested by Mat Colgrove also does not work:
```
program main
integer :: i
real, allocatable :: arr(:)
allocate(arr(10))
!$acc parallel loop private(arr(1:10)
do i=1,10
    arr=1.0
end do
end
```

with error

```

    5 | !$acc parallel loop private(arr(1:10))
      |                                1
Error: Syntax error in OpenMP variable list at (1)
```

These appear to be ICE compiler bugs as they are permitted by quite old OpenaCC
standards (and are seemingly typical use cases of OpenACC in Fortran). nvhpc
compilers work fine for this. 

The compile statement is 
`gfortran -foffload-options=-march=gfx90a -fopenacc test.f90`
with offloading onto an AMD MI210.

[Bug libgomp/107227] Compiler bug in private allocatable array in OpenACC compute statement

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107227

Thomas Schwinge <tschwinge at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-10-12
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |tschwinge at gcc dot gnu.org

--- Comment #1 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
Thanks for the report!

Probably a duplicate of PR93554: exactly same ICE, backtrace.

[Bug libgomp/107227] Compiler bug in private allocatable array in OpenACC compute statement

[tschwinge at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107227

--- Comment #2 from Thomas Schwinge <tschwinge at gcc dot gnu.org> ---
(In reply to Spencer Bryngelson from comment #0)
>     5 | !$acc parallel loop private(arr(1:10))
>       |                                1
> Error: Syntax error in OpenMP variable list at (1)

That's because, at this time, OpenACC subarray specifications do not apply to
'private' clauses, but only to data clauses.

This is being discussed in <https://github.com/OpenACC/openacc-spec/issues/59>
"private clause with subarrays" (only available to members of the GitHub
OpenACC organization).

[Bug libgomp/107227] Compiler bug in private allocatable array in OpenACC compute statement

[shb at gatech dot edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107227

--- Comment #3 from Spencer Bryngelson <shb at gatech dot edu> ---
Thanks @tschwinge! I found a few other replicate issues now that I look further
back, going at least to gcc10. Is there a plan to fix this? It seems important
(at least to me).