--- Comment #18 from burnus at gcc dot gnu dot org 2010-06-01 08:03 ---
Just for fun, I have feed it into NAG's f95 - and it prints:
Extension: gjff.f90, line 2: AC-implied-DO limit references control variable I
$ ./a.out
1 2 3 4 5
Where extension = vendor extension. (NAG also uses
--- Comment #19 from mikael at gcc dot gnu dot org 2010-06-01 14:09 ---
Created an attachment (id=20795)
-- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20795action=view)
Draft patch, version 2
Also pre-evaluate the lower bound.
for a case like this :
integer j(4)
I=5
--- Comment #20 from mikael at gcc dot gnu dot org 2010-06-01 14:13 ---
(In reply to comment #19)
for a case like this :
integer j(4)
I=5
j = (/(i,i=I-1,8)/)
You should read here :
j = (/(i,i=I,8)/)
end
--
--- Comment #21 from dfranke at gcc dot gnu dot org 2010-06-01 21:02
---
(In reply to comment #18)
Expected:
a) Allow it as extension (-std=gnu or -std=legacy; especially, for -std=gnu
one
could consider a default-enabled warning)
b) Reject it for -std=f(95,2003,2008)
I'd vote
--- Comment #1 from mikael at gcc dot gnu dot org 2010-05-31 17:43 ---
Note that fortran is case insensitive, ie i and I refer to the same variable.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44354
--- Comment #2 from dominiq at lps dot ens dot fr 2010-05-31 18:01 ---
Note that fortran is case insensitive, ...
Indeed, but I think the implied do loop should still go from 1 to 5. Note that
if I print 'i' after the loop I get 5.
--
--- Comment #3 from mikael at gcc dot gnu dot org 2010-05-31 18:04 ---
OK, it seems gfortran is wrong here.
The 4.8 section (Construction of array values) says :
/If an ac-value is an ac-implied-do, it is expanded
to form a sequence of elements under the control of the
--- Comment #4 from kargl at gcc dot gnu dot org 2010-05-31 18:33 ---
(In reply to comment #2)
Note that fortran is case insensitive, ...
Indeed, but I think the implied do loop should still go from 1 to 5. Note that
if I print 'i' after the loop I get 5.
Of course it prints
--- Comment #5 from dominiq at lps dot ens dot fr 2010-05-31 19:24 ---
The question becomes whether the 'I' in the implied-do-loop is
being used uninitialized.
From comment #3, I think the 'i' in i,i= should not be the same as the 'i' in
=1,i.
Confirmed. However, having this in
--- Comment #6 from kargl at gcc dot gnu dot org 2010-05-31 20:02 ---
(In reply to comment #5)
The question becomes whether the 'I' in the implied-do-loop is
being used uninitialized.
From comment #3, I think the 'i' in i,i= should not be the same as the 'i'
in
=1,i.
Well, it
--- Comment #7 from mikael at gcc dot gnu dot org 2010-05-31 21:31 ---
(In reply to comment #6)
because in the above 'i' and 'I' are in the same scoping unit.
I couldn't find what mandates in the standard that i and I are in a different
scoping unit/are different variables. Are they ?
--- Comment #8 from mikael at gcc dot gnu dot org 2010-05-31 21:33 ---
Created an attachment (id=20787)
-- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20787action=view)
draft patch
This makes loop bounds evaluation before the internal variable substitution.
--
--- Comment #9 from zeccav at gmail dot com 2010-05-31 21:37 ---
Subject: Re: incorrect output at run time
In my example 'i' is local to the array constructor, while 'I' is
global and is initialized with value 5, so that the statement should
display '1 2 3 4 5'. I agree that this is a
--- Comment #10 from mikael at gcc dot gnu dot org 2010-05-31 21:39 ---
(In reply to comment #6)
integer j(5)
I=5
j = 42
do i = 1, I
j(i) = i
end do
print '(A,I0,A,5(I0,1X))', 'I = ', I, ' j = ', j
end
because in the above
--- Comment #11 from kargl at gcc dot gnu dot org 2010-05-31 21:54 ---
(In reply to comment #7)
(In reply to comment #6)
because in the above 'i' and 'I' are in the same scoping unit.
I couldn't find what mandates in the standard that i and I are in a different
scoping unit/are
--- Comment #12 from kargl at gcc dot gnu dot org 2010-05-31 22:47 ---
(In reply to comment #8)
Created an attachment (id=20787)
-- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20787action=view) [edit]
draft patch
This makes loop bounds evaluation before the internal variable
--- Comment #13 from kargl at gcc dot gnu dot org 2010-05-31 23:44 ---
Due to my confusion over the scope of 'i' and 'I',
I posted to c.l.f. As usual Richard Maine pieced
through the standard's language.
--- Comment #14 from jvdelisle at gcc dot gnu dot org 2010-06-01 02:09
---
My take on this as I was reading through this thread before I got to comment
#13 is that the code has to be illegal. I vote for the error. I think it would
be bad practice too introduce this as an extension or
--- Comment #15 from sgk at troutmask dot apl dot washington dot edu
2010-06-01 03:07 ---
Subject: Re: incorrect output at run time
On Tue, Jun 01, 2010 at 02:09:38AM -, jvdelisle at gcc dot gnu dot org
wrote:
My take on this as I was reading through this thread before I got
--- Comment #16 from jvdelisle at verizon dot net 2010-06-01 03:46 ---
Subject: Re: incorrect output at run time
On 05/31/2010 08:07 PM, sgk at troutmask dot apl dot washington dot edu wrote:
--- Comment #15 from sgk at troutmask dot apl dot washington dot edu
2010-06-01 03:07
--- Comment #17 from pault at gcc dot gnu dot org 2010-06-01 04:31 ---
(In reply to comment #13)
Due to my confusion over the scope of 'i' and 'I',
I posted to c.l.f. As usual Richard Maine pieced
through the standard's language.
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