[Openmp-dev] [EXTERNAL] Re: Visual C/C++ OpenMP

[Natalia Glagoleva via Openmp-dev]

> Do you also plan to support OpenMP offloading, as an alternative to C++AMP?
Yes. Given the current state It'll take time though.

Thank you for invitation, we'll start attending - but I am not sure yet how that will work. You are way ahead, discussing 4.5 & 5.1 features - and we are finishing with 2.0 and starting to look at 3.1.

Natalia

-----Original Message-----
From: Michael Kruse <llvm at meinersbur.de> 
Sent: Friday, December 11, 2020 12:02 PM
To: Natalia Glagoleva <natgla at microsoft.com>
Cc: openmp-dev (openmp-dev at lists.llvm.org) <openmp-dev at lists.llvm.org>; Doerfert, Johannes <jdoerfert at anl.gov>; Eric Brumer <ericbr at microsoft.com>; Bran Hagger <brhagger at microsoft.com>; Joshua V. <joshua.viszlai at gmail.com>
Subject: [EXTERNAL] Re: [Openmp-dev] Visual C/C++ OpenMP

This sounds exciting. Do you also plan to support OpenMP offloading, as an alternative to C++AMP?

The OpenMP contributors have a weekly phone call where implementation questions are discussed. You might be interested to join. Details at
https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.google.com%2Fdocument%2Fd%2F1Tz8WFN13n7yJ-SCE0Qjqf9LmjGUw0dWO9Ts1ss4YOdg%2Fedit%3Fusp%3Dsharing&data=04%7C01%7Cnatgla%40microsoft.com%7C2e1a88ad322c44df4ab808d89e0fbff4%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637433138207560080%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=NLYrdtzpzirsLMnUZoHqMzmCQOGwlwl5CyoyK%2B8JCMo%3D&reserved=0

Michael

Am Fr., 11. Dez. 2020 um 12:40 Uhr schrieb Natalia Glagoleva via Openmp-dev <openmp-dev at lists.llvm.org>:
>
> Hello!
>
>
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> Visual C/C++ compiler team in Microsoft (see Cc list) is working on updating our support for OpenMP.
>
> Currently Visual C/C++ compiler supports OpenMP standard 2.0, with some exclusions. We started the work to support the newer standards.
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> As the first step we took LLVM OpenMP runtime library (libomp) and switched the Visual C/C++ compiler to generate code for OpenMP 2.0 for libomp, currently only for x64. The feature is in ‘experimental’ (or ‘beta’) state; should be available in the next release, Visual Studio version 16.9 preview 3, early next year. It’ll be available under a separate switch (-openmp:llvm), so people can try it out.
>
> With this update we’ve fixed a nasty bug for shared variables (was present in Visual C/C++ compiler) and added unsigned induction variables for for loops (was not supported previously). We’ve also added some initial limited support for tasks; that one is under additional -openmp:experimental switch (not ‘beta’ quality yet, and only a minimal set of clauses is supported). There will be a more detailed announcement at the time of the release.
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> As it’s beta, we don’t have yet full quality assessment. Our internal compiler tests passed, libomp runtime tests show that we don’t have a lot of features yet (which is expected), and there are some issues with tasks which we still need to look at. We plan to try https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.epcc.ed.ac.uk%2Fresearch%2Fcomputing%2Fperformance-characterisation-and-benchmarking%2Fepcc-openmp-micro-benchmark-suiterun&data=04%7C01%7Cnatgla%40microsoft.com%7C2e1a88ad322c44df4ab808d89e0fbff4%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637433138207560080%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=FdVVXCaoNTAAgn%2FZwkaHXw7KPJ48Pme1OK6KVR0DtCc%3D&reserved=0 next. I am doing performance measurements now.
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> We’ve done several changes to libomp (additional functions), and if the performance will be good, we’d like to upstream the changes.
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> Natalia Glagoleva, MSVC
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