On Sun, Nov 20, 2022 at 10:28:40PM +0100, Harald Anlauf via Fortran wrote:
> Steve,
>
> for unknown reasons I cannot reply to your mail on gmane,
> so trying directly via mailing list.
>
> I tried your patch, and it works on the supplied testcases.
>
> However, there is a scoping issue for the declaration of the
> index variable, as can be seen by the following variation:
>
> program foo
> use iso_fortran_env, only : k => real_kinds
> implicit none
> integer, parameter :: n = size(k)
> integer(8) :: i
> !!$ integer, parameter :: &
> !!$ & p(n) = [(precision(real(1.,k(i))), integer :: i = 1, n)]
> integer, parameter :: &
> & q(n) = [(kind(i), integer(2) :: i = 1, n)]
> integer, parameter :: &
> & r(n) = [(storage_size(i), integer(1) :: i = 1, n)]
> !!$ print *, p
> print *, q
> print *, r
> end program foo
>
> After your patch, gfortran prints:
>
> 8 8 8 8
> 64 64 64 64
>
> This suggests that the integer kind is taken from the host decl,
> which is kind=8, and not the local one (2 or 1).
>
> Crayftn (which chokes on your original testcase):
>
> 3*2
> 3*8
>
> This is what I expect.
>
> Intel doesn't accept storage_size() here, which is a bug.
> Commenting the uses of array r, I then get:
>
> 2 2 2
>
> At least this agrees with Cray.
>
> Can you have another look at this?
>
Unfortunately, gfortran does not define a namespace for an implied-do
index and uses a kludge by adding the attr.implied_index attribute to
the symbol. Unfortunately**2, gfortran uses gfc_match_iterator for
all places that 'i = start, stop [,step]' and there is no way to know
if what is being parsed. With the introduction of an optional typespec,
there is no easy way to deal with it in a clean way. Things get messy
quickly when trying to deal with implicit typing and explicitly typed
symbols. So, if the implied-do index has previously been typed such as
integer(8) i
print *, (i, integer(2) i=1, 3)
the integer(2) is ignored. That's this part of the gfc_match_iterator
diff
+ if (seen_ts && var->ts.type == BT_UNKNOWN)
+ {
+ var->ts.type = ts.type;
+ var->ts.kind = ts.kind;
+ var->symtree->n.sym->ts.type = ts.type;
+ var->symtree->n.sym->ts.kind = ts.kind;
+ }
Perhaps, a better way would be to simply create a shadow symbol
if a typespec appears in an iterator
print *, (i, integer i=1,3)
would become
print *, (_i, integer _i=1,3)
The issue is then that implied-do object list needs to be walked
and all occurrence of i must be replaced with _i.
--
Steve
