[Openmp-commits] [PATCH] D62393: [OPENMP][NVPTX]Mark parallel level counter as volatile.

[Johannes Doerfert via Phabricator via Openmp-commits]

jdoerfert added a comment.

In D62393#1542513 <https://reviews.llvm.org/D62393#1542513>, @ABataev wrote:

> In D62393#1542471 <https://reviews.llvm.org/D62393#1542471>, @jdoerfert wrote:
>
> > I want to investigate the racy accesses further and make sure it is not a miscompile inside LLVM.
>
>
> This is not a problem inside LLVM. The problem  appears after optimizations performed by the ptxas tool (when it compiles PTX to SASS) at O3 <https://reviews.llvm.org/owners/package/3/> with the inlined runtime.
>
> > I extracted the test case (see below) but I was not seeing the `ERROR`. How did you run the test case to see a different value for `Count`?
>
> You need to compile it with the inlined runtime at O2 <https://reviews.llvm.org/owners/package/2/> or O3 <https://reviews.llvm.org/owners/package/3/>.


When I run 
`./bin/clang -fopenmp-targets=nvptx64-nvida-cuda -O3 -fopenmp --cuda-path=/soft/compilers/cuda/cuda-9.1.85  -Xopenmp-target -march=sm_70  -fopenmp=libomp  test.c -o test.ll -emit-llvm -S`
I get

  https://gist.github.com/jdoerfert/4376a251d98171326d625f2fb67b5259

which shows the inlined and optimized libomptarget.

> And you need the latest version of the libomptarget

My version is from today Jun 13 15:24:11 2019, git: 3bc6e2a7aa3853b06045c42e81af094647c48676 <https://reviews.llvm.org/rG3bc6e2a7aa3853b06045c42e81af094647c48676>


Repository:
  rOMP OpenMP

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D62393/new/

https://reviews.llvm.org/D62393