[Openmp-dev] Build is terribly slow on Arm

[Jonas Hahnfeld via Openmp-dev]

You should not use Debug build to compare the performance of compilers.
As you're targeting different architectures, you might run into
different checks in the two backends. I believe it's possible this is
triggered by OpenMP code generation which might hit some corner cases.
This could also happen in Release builds, but might be less probable.

Also keep in mind that AArch64 (which you're probably talking about in
the context of HPC) now uses GlobalISel in some configurations. I don't
remember if it's with or without optimizations (or maybe even both
nowadays?), but you can try to deactivate this on the command line to
rule out this area.

Regards
Jonas

Am Dienstag, den 09.06.2020, 08:12 +0900 schrieb Itaru Kitayama via
Openmp-dev:
> They were both Debug build, but it took 20-25 minutes to finish on Arm.
> 
> On Tue, Jun 9, 2020 at 7:50 AM Itaru Kitayama <
> itaru.kitayama at gmail.com
> > wrote:
> > My OpenMP offloading app builds within a minute or so on
> > x86, but the same app takes longer than 5 minutes on Arm.
> > How do I investigate this further, supplying -v and post
> > the log here?
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