[hsa merge 07/10] IPA-HSA pass

[Alexander Monakov]

On Wed, 20 Jan 2016, Ilya Verbin wrote:
> I agree that OpenMP doesn't guarantee that all target regions must be executed
> on the device, but in this case a user can't be sure that some library function
> always will offload (because the library might be replaced by fallback version),
> and he/she will have to write something like:

I think there should be a way to allow the OpenMP runtime deduce what data
needs to be resynced on target region entries/exits in presence of fallback
execution; explicit copying via map(from/to:...) is a too big hammer for that.
I wonder if it was discussed.

It would be nice to be able to apply the idea of "debug counters" to target
region offloading in order to automatically bisect offload miscompilations:
force fallback execution for target region entries for Nth and next
executions; bisect by N to find the first incorrectly executing offload
region.  If the implementation cannot count on source program fully handling
arbitrary fallbacks, this idea doesn't work in general.

Alexander