[Openmp-commits] [PATCH] D111369: [OpenMP][FIX] Data race in the SPMD execution of the new runtime

[Johannes Doerfert via Phabricator via Openmp-commits]

jdoerfert created this revision.
jdoerfert added reviewers: jhuber6, ye-luo, tianshilei1992.
Herald added subscribers: guansong, bollu, yaxunl.
jdoerfert requested review of this revision.
Herald added a subscriber: sstefan1.
Herald added a project: OpenMP.

We need to synchronize the threads *before* we destroy the RAII objects
that hold the old values and not after to avoid threads executing the
parallel region but seeing an inconsistent state.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111369

Files:
  openmp/libomptarget/DeviceRTL/src/Parallelism.cpp


Index: openmp/libomptarget/DeviceRTL/src/Parallelism.cpp
===================================================================
--- openmp/libomptarget/DeviceRTL/src/Parallelism.cpp
+++ openmp/libomptarget/DeviceRTL/src/Parallelism.cpp
@@ -111,9 +111,10 @@
 
       if (TId < NumThreads)
         invokeMicrotask(TId, 0, fn, args, nargs);
+
+      // Synchronize all threads at the end of a parallel region.
+      synchronize::threadsAligned();
     }
-    // Synchronize all threads at the end of a parallel region.
-    synchronize::threadsAligned();
 
     ASSERT(state::ParallelTeamSize == 1u);
     ASSERT(icv::ActiveLevel == 0u);


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