From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 25B34382FC98; Thu, 24 Nov 2022 17:07:51 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 25B34382FC98
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1669309671;
	bh=nupJiuwuqvXu2KMOgv2fzcmh/3j9w7LOO9upyNrnbug=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=i/QFiryhRKMS8Uo1GSG80iauI1QgQVrguGP1+UXKuHki8YQ75UPCRBRZCUvZEZwov
	 ciXJskbu+/CMaIVfT2MrR0+DH9ERkRvgMF0wwgd1dtkK7MvcN++lgut+D1MEeJ3tAp
	 qV7MixMlWpx6zXDz6dJjBwkkEH6p5hMVO1tRMTPM=
From: "anlauf at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/107819] ICE in gfc_check_argument_var_dependency, at
 fortran/dependency.cc:978
Date: Thu, 24 Nov 2022 17:07:50 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: ice-on-invalid-code, ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: anlauf at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-107819-4-XytGZJkuMv@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-107819-4@http.gcc.gnu.org/bugzilla/>
References: <bug-107819-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D107819

--- Comment #5 from anlauf at gcc dot gnu.org ---
(In reply to Mikael Morin from comment #4)
> But is it required to generate a temporary?
> As I understand it, the code is invalid, and (correctly) diagnosed, so th=
ere
> is nothing else to do.
> It's invalid because of 15.5.2.13 Restrictions on entities associated with
> dummy arguments:
> (4) If the value of the entity or any subobject of it is affected through
> the dummy argument, then at any time during the invocation and execution =
of
> the procedure, either before or after the definition, it shall be referen=
ced
> only through that dummy argument unless (...)

Right.

I was confused by two observations.  First, NAG & Cray seem to generate
temporaries, while Intel and NVidia don't and would agree with gfortran
after the patch.

Second, I stumbled over:

! 15.5.2.3 Argument association
! (4) A present dummy argument with the VALUE attribute becomes argument
! associated with a definable anonymous data object whose initial value is
! the value of the actual argument.

So it boils down to what ELEMENTAL actually means in that context.  F2018:

15.8.3 Elemental subroutine actual arguments

! In a reference to an elemental subroutine, if the actual arguments
! corresponding to INTENT(OUT) and INTENT(INOUT) dummy arguments are
! arrays, the values of the elements, if any, of the results are the same
! as would be obtained if the subroutine had been applied separately, in
! array element order, to corresponding elements of each array actual
! argument.

So I read this that

   call s (a(n), a)

is to be interpreted as

  do i =3D 1, size (a)
     call s (a(n(i)), a(i))
  end do

and this would actually be well-defined behavior... ;-)=