From 5496d0da0bb6d11297253d6747034577299143f9 Mon Sep 17 00:00:00 2001
From: Eugene Zhulenev <ezhulenev@google.com>
Date: Tue, 26 Nov 2019 15:02:24 -0800
Subject: [PATCH] Add async evaluation support to TensorReverse

---
 unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
index 1db5d2e5e..c5830da0a 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
@@ -173,6 +173,15 @@ struct TensorEvaluator<const TensorReverseOp<ReverseDimensions, ArgType>, Device
     m_impl.evalSubExprsIfNeeded(NULL);
     return true;
   }
+
+#ifdef EIGEN_USE_THREADS
+  template <typename EvalSubExprsCallback>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalSubExprsIfNeededAsync(
+      EvaluatorPointerType, EvalSubExprsCallback done) {
+    m_impl.evalSubExprsIfNeededAsync(nullptr, [done](bool) { done(true); });
+  }
+#endif  // EIGEN_USE_THREADS
+
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup() {
     m_impl.cleanup();
   }