Hi FX,

On 11/28/23 18:07, FX Coudert wrote:
> Hi Harald,
> 
> The patch looks OK to me. Probably wait a bit for another opinion, since I’m not that active and I may have missed something.
> 
> Thanks,
> FX

thanks for having a look.

In the meantime I got an automated mail from the Linaro testers.
According to it there is a runtime failure of the testcase on
aarch64.  I couldn't see any useful traceback or else.

I tried the testcase on x86 with different options and found
an unexpected result only with -fsanitize=undefined and only
for the case of a rank-1 dummy when there is no actual argument
and the passed to another subroutine.  (valgrind is happy.)

Reduced reproducer:

! this fails with -fsanitize=undefined
program main
   call test_rank1 ()
contains
   subroutine test_rank1 (msg1)
     character(:), optional, allocatable :: msg1(:)
     if (present (msg1)) stop 77
     call assert_rank1 ()        ! <- no problem here
     call assert_rank1 (msg1)    ! <- problematic code path
   end

   subroutine assert_rank1 (msg2)
     character(:), optional, allocatable :: msg2(:)
     if (present (msg2)) stop 99 ! <- no problem if commented
   end
end


As far as I can tell, this could be a pre-existing (latent)
issue.  By looking at the tree-dump, the only thing that
appears fishy has been there before.  But then I am only
guessing that this is the problem observed on aarch64.

I have disabled the related call in the testcase of the
attached revised version.  As I do not see anything else,
I wonder if one could proceed with the current version
but open a PR for the reduced case above, unless someone
can pinpoint the place that is responsible for the above
failure.  (Is it the caller, or rather the function entry
code in the callee?)

Cheers,
Harald