[Openmp-dev] Offloading application build with a Trunk Debug Clang is so slow

[Jon Chesterfield via Openmp-dev]

On Wed, 18 Dec 2019, 19:51 Doerfert, Johannes, <jdoerfert at anl.gov> wrote:

> On 12/18, Itaru Kitayama via Openmp-dev wrote:
> > I've been using a Trunk Debug Clang that can print out libomptarget
> > debugging
> > information, but I noticed in the last couples of days the built time
> > increased
> > significantly to an hour or so. While a non Debug clang builds my app in
> a
> > few
> > minutes.
> > Has anyone committed intrusive changed recently to the library?
>
> Jon, do you know if something happened that could explain this?
>

 Hey,

The patches that landed in the last few days are all moving existing
functions behind a single call. The only vaguely interesting one for clang
is D71580 in that it uses templates that dispatch to cuda's min function,
but even that seems unlikely to change compile time.

It's 7k of pretty trivial C++, so taking over an hour to build doesn't
sound right. Have you tried rolling the deviceRTL back by a few days and
building with your current debug toolchain? I'm wondering if trunk clang's
debug build has regressed in performance.

Thanks

Jon
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