[LLVMdev] [RFC] Parallelization metadata and intrinsics in LLVM (for OpenMP, etc.)

Hal Finkel
Tue, 02 Oct 2012 23:42:20 -0000

On Mon, 01 Oct 2012 21:26:54 -0700
Chris Lattner <clattner at apple.com> wrote:

>
> On Oct 1, 2012, at 6:16 PM, greened at obbligato.org wrote:
>
> > Sanjoy Das <sanjoy at playingwithpointers.com> writes:
> >
> >> In short, I propose a intrinsic based approach which hinges on the
> >> concept of a "parallel map".  The immediate effect of
using
> >> intrinsics is that we no longer have to worry about missing
> >> metadata.  Moreover, we are still free to lower the intrinsics in
> >> a variety of ways -- including vectorizing them or lowering them
> >> to calls to an actual openmp backend.
> >
> > I'll re-ask here since this is in its own thread.
> >
> > Why can't we just make ordinary function calls to runtime
routines?
>
> I agree.  I can't imagine any practical way that a metadata-based
> approach could be preserved by optimizers.

Do you think it would be better to turn these things into actual syntax
extensions? This would obviously require more infrastructure work, but
it looks like we have a sufficient number of interested parties to
implement the changes.

Then we'd still need to decide what the appropriate level of
abstraction should be at the IR level. Opinions?

Thanks again,
Hal

>
> -Chris
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--
Hal Finkel
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory