From: Mikael Morin <morin-mikael@orange.fr>
To: Thomas Koenig <tkoenig@netcologne.de>, Harald Anlauf <anlauf@gmx.de>
Cc: Mikael Morin <mikael@gcc.gnu.org>,
gcc-patches@gcc.gnu.org, fortran@gcc.gnu.org
Subject: Re: [PATCH 09/10] fortran: Support clobbering of variable subreferences [PR88364]
Date: Tue, 20 Sep 2022 10:46:41 +0200 [thread overview]
Message-ID: <c18761e2-215a-8149-ff6e-00691536321e@orange.fr> (raw)
In-Reply-To: <10fc2a82-e23e-b488-66e3-9ef7c9e5d4ed@netcologne.de>
Le 20/09/2022 à 08:54, Thomas Koenig a écrit :
>
> On 19.09.22 22:50, Mikael Morin wrote:
>> Le 19/09/2022 à 21:46, Harald Anlauf a écrit :
>>>
>>> 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.
>>>
>> Couldn't you clobber A entirely? If no element of B is initialized in
>> SUB, well, A has undefined values on return from SUB. That's how
>> INTENT(OUT) works.
>
> Yes, I think so - you are passing the starting element of an array
> to an assumed-size array via storage association rules.
>
> It has to be an explicit interface, of course, otherwise it is
> unclear if an array or an array element is passed.
>
I have looked for the relevant excerpts from the standard.
From 15.5.2.11 (sequence association):
> If the dummy argument is not of type character
> with default or C character kind, and the actual argument is an array element designator, the element sequence
> consists of that array element and each element that follows it in array element order.
> If the dummy argument is
> assumed-size, the number of elements in the dummy argument is exactly the number of elements in the element
> sequence.
So the dummy size, even if not known to the programmer, is clearly
defined (to the full array size in your example).
next prev parent reply other threads:[~2022-09-20 8:46 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-16 20:24 [PATCH 00/10] fortran: clobber fixes [PR41453] Mikael Morin
2022-09-16 20:24 ` [PATCH 01/10] fortran: Move the clobber generation code Mikael Morin
2022-09-16 20:24 ` [PATCH 02/10] fortran: Fix invalid function decl clobber ICE [PR105012] Mikael Morin
2022-09-16 20:24 ` [PATCH 03/10] fortran: Move clobbers after evaluation of all arguments [PR106817] Mikael Morin
2022-09-16 20:24 ` [PATCH 04/10] fortran: Support clobbering with implicit interfaces [PR105012] Mikael Morin
2022-09-16 20:24 ` [PATCH 05/10] fortran: Support clobbering of reference variables [PR41453] Mikael Morin
2022-09-16 20:24 ` [PATCH 06/10] fortran: Support clobbering of SAVE variables [PR87395] Mikael Morin
2022-09-16 20:24 ` [PATCH 07/10] fortran: Support clobbering of ASSOCIATE variables [PR87397] Mikael Morin
2022-09-16 20:24 ` [PATCH 08/10] fortran: Support clobbering of allocatables and pointers [PR41453] Mikael Morin
2022-09-16 20:24 ` [PATCH 09/10] fortran: Support clobbering of variable subreferences [PR88364] Mikael Morin
2022-09-17 17:03 ` Thomas Koenig
2022-09-17 19:33 ` Mikael Morin
2022-09-17 19:49 ` Bernhard Reutner-Fischer
2022-09-17 19:50 ` Mikael Morin
2022-09-17 21:24 ` Bernhard Reutner-Fischer
2022-09-18 6:12 ` Richard Biener
2022-09-18 9:10 ` Mikael Morin
2022-09-18 10:23 ` Thomas Koenig
2022-09-18 18:32 ` Harald Anlauf
2022-09-18 20:55 ` Mikael Morin
2022-09-19 7:11 ` Mikael Morin
2022-09-19 19:46 ` Harald Anlauf
2022-09-19 20:50 ` Mikael Morin
2022-09-20 6:54 ` Thomas Koenig
2022-09-20 8:46 ` Mikael Morin [this message]
2022-09-20 21:08 ` Harald Anlauf
2022-09-20 21:08 ` Harald Anlauf
2022-09-21 9:57 ` Thomas Koenig
2022-09-21 18:56 ` Mikael Morin
2022-09-21 19:12 ` Harald Anlauf
2022-09-21 19:12 ` Harald Anlauf
2022-09-18 20:43 ` Mikael Morin
2022-09-18 10:48 ` Richard Biener
2022-09-19 7:31 ` Mikael Morin
2022-09-19 7:58 ` Richard Biener
2022-09-16 20:24 ` [PATCH 10/10] fortran: Support clobbering of derived types [PR41453] Mikael Morin
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