[Openmp-commits] [PATCH] D62393: [OPENMP][NVPTX]Mark parallel level counter as volatile.

Olivier Giroux via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Thu Jun 13 10:29:54 PDT 2019

__simt__ added a comment.

In D62393#1542042 <https://reviews.llvm.org/D62393#1542042>, @tra wrote:

> C++ volatile will give you that. You also rely on atomicity. C++ volatile does not guarantee that, even if NVPTX does happen to. It's a mere coincidence. What if next PTX revision provides a better way to implement C++ volatile without providing atomicity? Then your code will all of a sudden break in new and exciting ways.

I think it's completely healthy and fair to be skeptical that we'll do the right thing by you, but FWIW the changes I want to make to CUDA `volatile` after we ship `std::atomic<T>` go in the other direction. And the legacy requirements are pretty entrenched here, too.

  rOMP OpenMP



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