[Openmp-commits] [PATCH] D77609: [OpenMP] Added the support for hidden helper task in RTL

[Joachim Protze via Phabricator via Openmp-commits]

protze.joachim added a comment.

In D77609#2631784 <https://reviews.llvm.org/D77609#2631784>, @ronlieb wrote:

> i tried using 
> export LIBOMP_USE_HIDDEN_HELPER_TASK=0 and rebuilding/rerunning spec cpu2017 fpspeed base.
>
> and still see the performance issues in 619.lbm and all the other fpspeed benchmarks.
> The GeoMean dropped aprox 30%

Wasn't spec cpu meant to measure single-core performance? I can see how -fopenmp or -fopenmp-simd might help to turn on vectorization. But none of these flags should turn on OpenMP directives present in the code and make the code multi-threaded (in spec cpu 2006 there were actually `#if !defined(SPEC_CPU)` arround all OpenMP directives and includes). Are the resulting binaries really linked against libomp? Without any OpenMP symbols in the application, the linker should just drop libomp.


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  https://reviews.llvm.org/D77609/new/

https://reviews.llvm.org/D77609