Fix incorrect pointer checking for scatter and gather (#285)

src/misc/argcheck.cc

@@ -73,10 +73,10 @@ ncclResult_t ArgsCheck(struct ncclInfo* info) {
       }
     } else {
       // Check CUDA device pointers
-      if (info->coll != ncclCollBroadcast || info->comm->rank == info->root) {
+      if ((info->coll != ncclCollBroadcast && info->coll != ncclCollScatter) || info->comm->rank == info->root) {
         NCCLCHECK(CudaPtrCheck(info->sendbuff, info->comm, "sendbuff", info->opName));
       }
-      if (info->coll != ncclCollReduce || info->comm->rank == info->root) {
+      if ((info->coll != ncclCollReduce && info->coll != ncclCollGather) || info->comm->rank == info->root) {
         NCCLCHECK(CudaPtrCheck(info->recvbuff, info->comm, "recvbuff", info->opName));
       }
     }