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From: Harald Anlauf <anlauf@gmx.de>
Subject: Re: [PATCH 09/10] fortran: Support clobbering of variable
 subreferences [PR88364]
Date: Mon, 19 Sep 2022 21:46:47 +0200
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Am 18.09.22 um 22:55 schrieb Mikael Morin:
> Le 18/09/2022 à 20:32, Harald Anlauf a écrit :
>>
>> Assumed shape will be on the easy side,
>> while assumed size likely needs to be excluded for clobbering.
>>
> Isn’t it the converse that is true?
> Assumed shape can be non-contiguous so have to be excluded, but assumed 
> size are contiguous, so valid candidates for clobbering. No?

I really was referring here to *dummies*, as in the following example:

program p
   integer :: a(4)
   a = 1
   call sub (a(1), 2)
   print *, a
contains
   subroutine sub (b, k)
     integer, intent(in)  :: k
     integer, intent(out) :: b(*)
!   integer, intent(out) :: b(k)
     if (k > 2) b(k) = k
   end subroutine sub
end program p

Assumed size (*) is just a contiguous hunk of memory of possibly
unknown size, which can be zero.  So you couldn't set a clobber
for the a(1) actual argument.

> No way, really, arrays are going to be a maze of complexity.

Agreed.