From: Steve Kargl <sgk@troutmask.apl.washington.edu>
To: "Thomas König" <tk@tkoenig.net>
Cc: fortran@gcc.gnu.org
Subject: Re: Odd bug from Stack Overflow
Date: Sun, 18 Mar 2018 17:19:00 -0000 [thread overview]
Message-ID: <20180318171913.GA61043@troutmask.apl.washington.edu> (raw)
In-Reply-To: <5b6dfedc-425f-6e60-7ef1-4dee23eb2b27@tkoenig.net>
On Sun, Mar 18, 2018 at 06:12:23PM +0100, Thomas König wrote:
> Hi Steve,
>
> This looks like a missing conversion somewhere,
> because this works:
>
> program test
> implicit none
> integer, parameter :: n = 65536
> real, dimension(n) :: y
> integer :: i
> y = (/ (1.0, i=1, n) /)
> print *,y(2)
> if (y(2) /= 1) stop 1
> end program test
>
> Also, n=65536 is a limit... setting n=2**16-1 actually
> works as expected with the orginal test case.
Yes, n=2**16-1 works because gfortran switches over from
expanding the array constructor into a static temporary
variable to scalarizing the implied-do-loop at 2**16. It
is a trade-off we made a long time ago for
integer, parameter :: i(somebignumber) = [(i,i=1,somebignumer)]
See -fmax-array-constructor= option.
> This looks like a resolution problem, not something
> in the scalarizer. Can you open a PR?
Yes.
--
Steve
prev parent reply other threads:[~2018-03-18 17:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-18 15:40 Steve Kargl
2018-03-18 16:03 ` Steve Kargl
2018-03-18 17:12 ` Thomas König
2018-03-18 17:19 ` Steve Kargl [this message]
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