vendor/llvm-project/llvmorg-13.0.1-0-g75e33f71c2davendor/llvm-project/release-13.x

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Support/Parallel.cpp b/llvm/lib/Support/Parallel.cpp
index 9a2e1003da5a..71e3a1362f7e 100644
--- a/llvm/lib/Support/Parallel.cpp
+++ b/llvm/lib/Support/Parallel.cpp
@@ -151,7 +151,12 @@ static std::atomic<int> TaskGroupInstances;
 // lock, only allow the first TaskGroup to run tasks parallelly. In the scenario
 // of nested parallel_for_each(), only the outermost one runs parallelly.
 TaskGroup::TaskGroup() : Parallel(TaskGroupInstances++ == 0) {}
-TaskGroup::~TaskGroup() { --TaskGroupInstances; }
+TaskGroup::~TaskGroup() {
+  // We must ensure that all the workloads have finished before decrementing the
+  // instances count.
+  L.sync();
+  --TaskGroupInstances;
+}
 
 void TaskGroup::spawn(std::function<void()> F) {
   if (Parallel) {