diff --git a/ompi/mca/coll/base/coll_base_allgatherv.c b/ompi/mca/coll/base/coll_base_allgatherv.c
index e835d20345..460c0b2db8 100644
--- a/ompi/mca/coll/base/coll_base_allgatherv.c
+++ b/ompi/mca/coll/base/coll_base_allgatherv.c
@@ -11,7 +11,7 @@
  * Copyright (c) 2004-2005 The Regents of the University of California.
  *                         All rights reserved.
  * Copyright (c) 2009      University of Houston. All rights reserved.
- * Copyright (c) 2013      Los Alamos National Security, LLC. All Rights
+ * Copyright (c) 2013-2017 Los Alamos National Security, LLC. All Rights
  *                         reserved.
  * Copyright (c) 2015-2016 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
@@ -596,7 +596,7 @@ ompi_coll_base_allgatherv_intra_basic_default(const void *sbuf, int scount,
                                               struct ompi_communicator_t *comm,
                                               mca_coll_base_module_t *module)
 {
-    int i, size, rank, err;
+    int size, rank, err;
     MPI_Aint extent, lb;
     char *send_buf = NULL;
     struct ompi_datatype_t *newtype, *send_type;
diff --git a/ompi/mca/coll/libnbc/nbc_iallreduce.c b/ompi/mca/coll/libnbc/nbc_iallreduce.c
index 0e267d11dc..6b6b9c7fc0 100644
--- a/ompi/mca/coll/libnbc/nbc_iallreduce.c
+++ b/ompi/mca/coll/libnbc/nbc_iallreduce.c
@@ -5,7 +5,7 @@
  *                         Corporation.  All rights reserved.
  * Copyright (c) 2006      The Technical University of Chemnitz. All
  *                         rights reserved.
- * Copyright (c) 2013-2015 Los Alamos National Security, LLC. All rights
+ * Copyright (c) 2013-2017 Los Alamos National Security, LLC. All rights
  *                         reserved.
  * Copyright (c) 2014-2017 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
@@ -61,7 +61,7 @@ int ompi_coll_libnbc_iallreduce(const void* sendbuf, void* recvbuf, int count, M
 #endif
   enum { NBC_ARED_BINOMIAL, NBC_ARED_RING } alg;
   char inplace;
-  NBC_Handle *handle;
+  NBC_Handle *handle = NULL;
   ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module;
   ptrdiff_t span, gap;
 
diff --git a/ompi/mca/coll/libnbc/nbc_ialltoallv.c b/ompi/mca/coll/libnbc/nbc_ialltoallv.c
index d39838124d..d714dea4c5 100644
--- a/ompi/mca/coll/libnbc/nbc_ialltoallv.c
+++ b/ompi/mca/coll/libnbc/nbc_ialltoallv.c
@@ -7,7 +7,7 @@
  *                         rights reserved.
  * Copyright (c) 2014-2016 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
- * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
+ * Copyright (c) 2015-2017 Los Alamos National Security, LLC. All rights
  *                         reserved.
  *
  * Author(s): Torsten Hoefler <htor@cs.indiana.edu>
@@ -214,6 +214,7 @@ int ompi_coll_libnbc_ialltoallv_inter (const void* sendbuf, const int *sendcount
   return OMPI_SUCCESS;
 }
 
+__opal_attribute_unused__
 static inline int a2av_sched_linear(int rank, int p, NBC_Schedule *schedule,
                                     const void *sendbuf, const int *sendcounts, const int *sdispls,
                                     MPI_Aint sndext, MPI_Datatype sendtype,
@@ -248,6 +249,7 @@ static inline int a2av_sched_linear(int rank, int p, NBC_Schedule *schedule,
   return OMPI_SUCCESS;
 }
 
+__opal_attribute_unused__
 static inline int a2av_sched_pairwise(int rank, int p, NBC_Schedule *schedule,
                                       const void *sendbuf, const int *sendcounts, const int *sdispls,
                                       MPI_Aint sndext, MPI_Datatype sendtype,
diff --git a/ompi/mca/coll/libnbc/nbc_ialltoallw.c b/ompi/mca/coll/libnbc/nbc_ialltoallw.c
index ec29a3a355..1dadf98149 100644
--- a/ompi/mca/coll/libnbc/nbc_ialltoallw.c
+++ b/ompi/mca/coll/libnbc/nbc_ialltoallw.c
@@ -7,7 +7,7 @@
  *                         rights reserved.
  * Copyright (c) 2014-2016 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
- * Copyright (c) 2015      Los Alamos National Security, LLC. All rights
+ * Copyright (c) 2015-2017 Los Alamos National Security, LLC. All rights
  *                         reserved.
  *
  * Author(s): Torsten Hoefler <htor@cs.indiana.edu>
@@ -218,6 +218,7 @@ static inline int a2aw_sched_linear(int rank, int p, NBC_Schedule *schedule,
   return OMPI_SUCCESS;
 }
 
+__opal_attribute_unused__
 static inline int a2aw_sched_pairwise(int rank, int p, NBC_Schedule *schedule,
                                       const void *sendbuf, const int *sendcounts, const int *sdispls,
                                       struct ompi_datatype_t * const * sendtypes,