Upstreaming changes to OpenMP runtime made for Visual C++ compiler

Hello to everyone,

Earlier Microsoft announced that Visual C++ compiler has new experimental switch -openmp:llvm for OpenMP support based on LLVM runtime. In VS 16.9 we’ve done support for OpenMP 2.0 on x64, in VS 16.10 we’ve also done support for OpenMP 2.0 on x86 and arm64 (we’ll be blogging about it soon).

We’d really like to upstream all of our changes, so that people will be able to build OpenMP runtime to be used with Visual C++ compiler if they want/need to. We have several separate changes. One of the first ones which is more-or-less ready for a review is for building libomp dll for Windows, arm64.

Let us know what do you think and/or what you’d like to see from us. Chris plans to submit a patch late this week / early next week.

Thank you,


Hi Natalia,

great news!

I would suggest "small" changes with tests uploaded to phabricator should be fine.
You should also consider to set up a public buildbot for OpenMP on windows compiled
with your compiler, etc.

Feel free to join our OpenMP in LLVM call Wednesday mornings, you can add items to the
agenda if you want to present/discuss them:

~ Johannes