Re: [patch] Fortran fix for PR70289

[Cesar Philippidis <cesar@codesourcery.com>]

On 04/01/2016 07:56 AM, Jakub Jelinek wrote:
> On Fri, Apr 01, 2016 at 07:49:16AM -0700, Cesar Philippidis wrote:
>> The bug in PR70289 is an assertion failure triggered by a static
>> variable used inside an offloaded acc region which doesn't have a data
>> clause associated with it. Basically, that static variable ends up in a
>> different lto partition, which was not streamed to the offloaded
>> compiler. I'm not sure if we should try to replicate the static storage
>> in the offloaded regions, but it probably doesn't make sense in a
>> parallel environment anyway.
> 
> Is this really Fortran specific?  I'd expect the diagnostics to be in
> gimplify.c and handle it for all 3 FEs...

By the time the variable reaches the gimplifier, the reduction variable
may no longer match the ones inside the data clause. E.g. consider this
directive inside a fortran subroutine:

  !$acc parallel copyout(temp) reduction(+:temp)

The gimplifier would see something like:

  map(force_from:*temp.2 [len: 4]) map(alloc:temp [pointer assign, bias:
0]) reduction(+:temp)

At this point, unless I'm mistaken, it would be difficult to tell if
temp.2 is a pointer to the same temp in the reduction. Maybe I'm missing
something?

Cesar