https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125717
Harald Anlauf <anlauf at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |tkoenig at gcc dot gnu.org
--- Comment #4 from Harald Anlauf <anlauf at gcc dot gnu.org> ---
(In reply to Dhruv Chawla from comment #3)
> (In reply to Harald Anlauf from comment #2)
> > (In reply to Richard Biener from comment #1)
> > > The auto-parallelizer has not changed, it's unmaintained. IIRC the issue
> > > is
> > > that the dependences idea of the auto-parallelizer and do concurrent are
> > > not
> > > compatible. In principle the frontend could be more selective with
> > > setting
> > > the flag, but DO CONCURRENT does not mean there are no dependences at
> > > all(?)
> >
> > F2023: 11.1.7.4.3 The execution cycle
> >
> > (3) The block of a DO CONCURRENT construct is executed for every active
> > combination of the index-name values. Each execution of the block is an
> > iteration. The executions may occur in any order.
> >
> >
> > There is a couple of restrictions in
> >
> > 11.1.7.5 Additional semantics for DO CONCURRENT constructs
> >
> > and at the end:
> >
> > NOTE 3
> >
> > The restrictions on the statements in a DO CONCURRENT construct are designed
> > to ensure there are no data dependencies between iterations of the loop.
> > This permits code optimizations that might otherwise be difficult or
> > impossible because they would depend on properties of the program not
> > visible to the compiler.
>
> This makes me curious as to why the annotation was changed to be this way in
> the first place. Shouldn't the language construct by-default guarantee it
> working correctly?
>
> It looks like this was supposed to be handled in GCC 9:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83064#c24, so was it? Was this
> just something that was forgotten along the way?
Hmm, I cannot say. But I read Thomas' comment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83064#c31
as that this is still to be done.
Adding Thomas.
@Thomas: do you remember the status of this issue?
