[Llvm-bgq-discuss] bgclang r203443-20140309 on vesta/mira

[Hal Finkel]

A quick update:

The r203443-20140309 OpenMP runtime library has been updated. This fixes a bug where calling omp_set_num_threads(int), and several similar functions, would cause the application to segfault.

For those maintaining their own installs, updated RPMs (and SRPMs) are available on the trac page: https://trac.alcf.anl.gov/projects/llvm-bgq

Thanks again,
Hal

----- Original Message -----
> From: "Hal Finkel" <hfinkel at anl.gov>
> To: llvm-bgq-discuss at lists.alcf.anl.gov
> Sent: Monday, March 10, 2014 11:45:45 AM
> Subject: [Llvm-bgq-discuss]  bgclang r203443-20140309 on vesta/mira
> 
> Hello again,
> 
> I've updated our bgclang install on vesta and mira to
> r203443-20140309. A fair amount has changed, here's a summary:
> 
>  - First, we pick up the last month's work of upstream development
>  work. Notably, this includes a feature I developed for the PowerPC
>  backend to track boolean variables in individual CR bits. This is a
>  major addition, and gives some nice performance improvements for
>  control-flow dominated code, but if you want to turn it off, pass
>  -mno-crbits to bgclang.
> 
>  - Second, I've rebased the OpenMP runtime library, and it is now
>  derived from the latest version from LLVM's repository (and this
>  version can be built by clang, not just gcc, and so the runtime
>  library itself is now compiled by bgclang). This new version has
>  some support for the new cancellation API (which I've not tried
>  myself, but if someone is curious, please feel free to try it out
>  and let us know if/how it works).
> 
>  - Third, I've changed the way that libc++, which is used by
>  bgclang++11, is compiled. We need to use a configuration where both
>  libc++ and libstdc++ can be linked together (because of
>  dependencies in the BG/Q messaging implementation). We had been
>  using a mode I had hacked up myself (because there was no upstream
>  support), but now there is upstream support for this configuration,
>  and we've switched to using the upstream method.
> 
>  - Use of LLVM's integrated assembler is now supported (and has full
>  QPX support). You can pass -fintegrated-as to bgclang to try it
>  out. There should be no observable difference in the output, but
>  should be a little faster (in terms of compilation time).
> 
> For those maintaining their own installs, RPMs (and SRPMs) are
> available on the trac page:
> https://trac.alcf.anl.gov/projects/llvm-bgq
> 
> The upstream codebase has now switched to really requiring a
> compliant C++11 compiler and standard library in order to compile
> LLVM. As a result, the bgclang packages can no longer be built with
> the system g++, and so I've packaged a 'stage 1' clang/libcxx
> configuration, based on the 3.4 release, that is now used to build
> bgclang. I've updated the installation instructions on the website,
> but in short, you'll now need to install the 'stage 1' packages as
> well.
> 
> Thanks again,
> Hal
> 
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
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-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory