Re: [PATCH 0/8] NVPTX offloading to NVPTX: backend patches

[Alexander Monakov <amonakov at ispras dot ru>]

On Mon, 17 Oct 2016, Bernd Schmidt wrote:
> On 10/14/2016 06:39 PM, Alexander Monakov wrote:
> > I'm resending the patch series with backend prerequisites for OpenMP
> > offloading to the NVIDIA PTX ISA.  The patches are rebased on trunk.
> 
> What's the status of the branch? Is it expected to work? I'm trying to compile
> the OpenMP version of these benchmarks:
>   https://codesign.llnl.gov/lulesh.php
> 
> and the resulting binary fails as follows:
> 
> libgomp: Link error log error   : Size doesn't match for '__nvptx_stacks' in
> 'Input 8', first specified in 'Input 8'
> error   : Multiple definition of '__nvptx_stacks' in 'Input 8', first defined
> in 'Input 8'

I've just pushed two commits to the branch to fix this issue.  Before those, the
last commit left the branch in a state where an incremental build seemed ok
(because libgcc/libgomp weren't rebuilt with the new cc1), but a from-scratch
build was broken like you've shown.  LULESH is known to work.  I also intend to
perform a trunk merge soon.

> I think before merging this work we'll need to have some idea of how well it
> works on real-world code.

This patchset and the branch lay the foundation, there's more work to be
done, in particular on the performance improvements side. There should be
an agreement on these fundamental bits first, before moving on to fine-tuning.

Alexander