From b02fd0416596d9e507e898fd0377255bbc0e0397 Mon Sep 17 00:00:00 2001
From: Wenkai Du <43822138+wenkaidu@users.noreply.github.com>
Date: Mon, 20 Mar 2023 15:34:09 -0700
Subject: [PATCH] Fix unit test HIP graph error (#712)

---
 src/enqueue.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/enqueue.cc b/src/enqueue.cc
index 33502ef928..d01817a0e9 100644
--- a/src/enqueue.cc
+++ b/src/enqueue.cc
@@ -938,7 +938,7 @@ ncclResult_t ncclLaunchPrepare(struct ncclComm* comm) {
         NCCLCHECKGOTO(ncclStrongStreamWaitStream(tasks->capturingGraph, &comm->deviceStream, l->stream), result, failure);
       }
       NCCLCHECKGOTO(ncclStrongStreamWaitStream(tasks->capturingGraph, launchStream, &comm->deviceStream), result, failure);
-    } else if (tasks->streams->stream != comm->lastStream) {
+    } else if (tasks->streams->stream != comm->lastStream && comm->lastStream != nullptr) {
       // Stream changed from last call, create dependency against last NCCL kernel launch
       CUDACHECK(hipStreamWaitEvent(tasks->streams->stream, comm->doneEvent, 0));
     }