[ReleaseNotes] Mention OpenMP Tools Interface in runtime library

[Hahnfeld]

Summary

The OpenMP runtime has no dedicated Release Notes, so add it to Clang's section about OpenMP.

[hans]

Sounds good to me.

docs/ReleaseNotes.rst

230 ↗

(On Diff #130806)

Is there a missing right-angle bracket, >, here?

[omalyshe]

docs/ReleaseNotes.rst

227 ↗

(On Diff #130806)

I'd suggest not mentioning any percentage. A note about possible performance issue due to enabling OMPT would be enough.

[Hahnfeld]

Address review comments.

docs/ReleaseNotes.rst

230 ↗

(On Diff #130806)

Yes, and an underscore. I though I was smart enough to write reStructuredText without actually "testing" it...

[omalyshe]

docs/ReleaseNotes.rst

226 ↗

(On Diff #130900)

Linux*, Windows* and macOS*

[Hahnfeld]

docs/ReleaseNotes.rst

226 ↗

(On Diff #130900)

That's done nowhere else in Clang's documentation so I'm strongly opposed to doing it here unless you have a very good legal reason that nobody else knows about.

[omalyshe]

docs/ReleaseNotes.rst

226 ↗

(On Diff #130900)

I'm OK with omitting "*" but "macOS" should be definitely fixed ;)

[Hahnfeld]

Fix macOS.

[omalyshe]

LGTM

cfe/branches/release_60/docs/ReleaseNotes.rst

 - Added support for almost all target-based directives except for
   `#pragma omp target teams distribute parallel for [simd]`. Although, please
   note that `depend` clauses on target-based directives are not supported yet.
   Clang supports offloading to X86_64, AArch64 and PPC64[LE] devices.
 
 - Added support for `reduction`-based clauses on `task`-based directives from
   upcoming OpenMP 5.0.
 
+- The LLVM OpenMP runtime `libomp` now supports the OpenMP Tools Interface (OMPT)
+  on x86, x86_64, AArch64, and PPC64 on Linux, Windows, and macOS. If you observe
+  a measurable performance impact on one of your applications without a tool
+  attached, please rebuild the runtime library with `-DLIBOMP_OMPT_SUPPORT=OFF` and
+  file a bug at `LLVM's Bugzilla <https://bugs.llvm.org/>`_ or send a message to the
+  `OpenMP development list <http://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev>`_.
+
 Internal API Changes
 --------------------
 
 These are major API changes that have happened since the 4.0.0 release of
 Clang. If upgrading an external codebase that uses Clang as a library,
 this section should help get you past the largest hurdles of upgrading.
 
 -  ...