[Openmp-commits] [PATCH] D112861: [OpenMP][DeviceRTL] Fixed an issue that causes hang in SU3

[Shilei Tian via Phabricator via Openmp-commits]

tianshilei1992 created this revision.
tianshilei1992 added reviewers: jdoerfert, jhuber6.
Herald added subscribers: guansong, yaxunl.
tianshilei1992 requested review of this revision.
Herald added subscribers: openmp-commits, sstefan1.
Herald added a project: OpenMP.

The synchronization at the end of parallel region cannot make sure all threads
exit the scope. As a result, the assertions right after it might be hit, and
further the `state::assumeInitialState(IsSPMD)` in `__kmpc_target_deinit` may
not hold as well. We either add a synchronization right after the parallel region,
or remove the assertions and assuptions. Here we choose the first one as those
assertions and assumptions can help optimizations.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112861

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
@@ -123,6 +123,11 @@
       synchronize::threadsAligned();
     }
 
+    // Synchronize all threads to make sure every thread exits the scope above;
+    // otherwise the following assertions and the assumption in
+    // __kmpc_target_deinit may not hold.
+    synchronize::threadsAligned();
+
     ASSERT(state::ParallelTeamSize == 1u);
     ASSERT(icv::ActiveLevel == 0u);
     ASSERT(icv::Level == 0u);


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