diff --git a/ompi/mpi/c/alltoall.c b/ompi/mpi/c/alltoall.c
index 7426c01f46..be39433ba1 100644
--- a/ompi/mpi/c/alltoall.c
+++ b/ompi/mpi/c/alltoall.c
@@ -51,11 +51,13 @@ int MPI_Alltoall(const void *sendbuf, int sendcount, MPI_Datatype sendtype,
     int err;
 
     MEMCHECKER(
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-        memchecker_call(&opal_memchecker_base_isdefined, sendbuf, sendcount, sendtype);
-        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
         memchecker_comm(comm);
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            memchecker_call(&opal_memchecker_base_isdefined, (void *)sendbuf, sendcount, sendtype);
+        }
+        memchecker_datatype(recvtype);
+        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
     );
 
     if (MPI_PARAM_CHECK) {
diff --git a/ompi/mpi/c/alltoallv.c b/ompi/mpi/c/alltoallv.c
index 03cea136cf..00b09f5d49 100644
--- a/ompi/mpi/c/alltoallv.c
+++ b/ompi/mpi/c/alltoallv.c
@@ -56,20 +56,23 @@ int MPI_Alltoallv(const void *sendbuf, const int sendcounts[],
         ptrdiff_t recv_ext;
         ptrdiff_t send_ext;
 
-        memchecker_datatype(sendtype);
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            ompi_datatype_type_extent(sendtype, &send_ext);
+        }
         memchecker_datatype(recvtype);
-
         ompi_datatype_type_extent(recvtype, &recv_ext);
-        ompi_datatype_type_extent(sendtype, &send_ext);
 
         memchecker_comm(comm);
 
         size = OMPI_COMM_IS_INTER(comm)?ompi_comm_remote_size(comm):ompi_comm_size(comm);
         for ( i = 0; i < size; i++ ) {
-            /* check if send chunks are defined. */
-            memchecker_call(&opal_memchecker_base_isdefined,
-                            (char *)(sendbuf)+sdispls[i]*send_ext,
-                            sendcounts[i], sendtype);
+            if (MPI_IN_PLACE != sendbuf) {
+                /* check if send chunks are defined. */
+                memchecker_call(&opal_memchecker_base_isdefined,
+                                (char *)(sendbuf)+sdispls[i]*send_ext,
+                                sendcounts[i], sendtype);
+            }
             /* check if receive chunks are addressable. */
             memchecker_call(&opal_memchecker_base_isaddressable,
                             (char *)(recvbuf)+rdispls[i]*recv_ext,
diff --git a/ompi/mpi/c/alltoallw.c b/ompi/mpi/c/alltoallw.c
index 802e9df55c..01d8edcf0a 100644
--- a/ompi/mpi/c/alltoallw.c
+++ b/ompi/mpi/c/alltoallw.c
@@ -60,17 +60,17 @@ int MPI_Alltoallw(const void *sendbuf, const int sendcounts[],
 
         size = OMPI_COMM_IS_INTER(comm)?ompi_comm_remote_size(comm):ompi_comm_size(comm);
         for ( i = 0; i < size; i++ ) {
-            memchecker_datatype(sendtypes[i]);
+            if (MPI_IN_PLACE != sendbuf) {
+                memchecker_datatype(sendtypes[i]);
+                ompi_datatype_type_extent(sendtypes[i], &send_ext);
+                memchecker_call(&opal_memchecker_base_isdefined,
+                                (char *)(sendbuf)+sdispls[i]*send_ext,
+                                sendcounts[i], sendtypes[i]);
+            }
             memchecker_datatype(recvtypes[i]);
-            
-            ompi_datatype_type_extent(sendtypes[i], &send_ext);
             ompi_datatype_type_extent(recvtypes[i], &recv_ext);
-
-            memchecker_call(&opal_memchecker_base_isdefined,
-                            (char *)(sendbuf)+sdispls[i]*send_ext,
-                            sendcounts[i], sendtypes[i]);
             memchecker_call(&opal_memchecker_base_isaddressable,
-                            (char *)(recvbuf)+sdispls[i]*recv_ext,
+                            (char *)(recvbuf)+rdispls[i]*recv_ext,
                             recvcounts[i], recvtypes[i]);
         }
     );
diff --git a/ompi/mpi/c/ialltoall.c b/ompi/mpi/c/ialltoall.c
index 41ea7491fe..9fe00f97be 100644
--- a/ompi/mpi/c/ialltoall.c
+++ b/ompi/mpi/c/ialltoall.c
@@ -52,11 +52,13 @@ int MPI_Ialltoall(const void *sendbuf, int sendcount, MPI_Datatype sendtype,
     int err;
 
     MEMCHECKER(
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-        memchecker_call(&opal_memchecker_base_isdefined, sendbuf, sendcount, sendtype);
-        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
         memchecker_comm(comm);
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            memchecker_call(&opal_memchecker_base_isdefined, (void *)sendbuf, sendcount, sendtype);
+        }
+        memchecker_datatype(recvtype);
+        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
     );
 
     if (MPI_PARAM_CHECK) {
diff --git a/ompi/mpi/c/ialltoallv.c b/ompi/mpi/c/ialltoallv.c
index 579722567a..19cb022c1d 100644
--- a/ompi/mpi/c/ialltoallv.c
+++ b/ompi/mpi/c/ialltoallv.c
@@ -55,20 +55,24 @@ int MPI_Ialltoallv(const void *sendbuf, const int sendcounts[], const int sdispl
         ptrdiff_t recv_ext;
         ptrdiff_t send_ext;
 
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-
-        ompi_datatype_type_extent(recvtype, &recv_ext);
-        ompi_datatype_type_extent(sendtype, &send_ext);
-
         memchecker_comm(comm);
 
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            ompi_datatype_type_extent(sendtype, &send_ext);
+        }
+
+        memchecker_datatype(recvtype);
+        ompi_datatype_type_extent(recvtype, &recv_ext);
+
         size = OMPI_COMM_IS_INTER(comm)?ompi_comm_remote_size(comm):ompi_comm_size(comm);
         for ( i = 0; i < size; i++ ) {
-            /* check if send chunks are defined. */
-            memchecker_call(&opal_memchecker_base_isdefined,
-                            (char *)(sendbuf)+sdispls[i]*send_ext,
-                            sendcounts[i], sendtype);
+            if (MPI_IN_PLACE != sendbuf) {
+                /* check if send chunks are defined. */
+                memchecker_call(&opal_memchecker_base_isdefined,
+                                (char *)(sendbuf)+sdispls[i]*send_ext,
+                                sendcounts[i], sendtype);
+            }
             /* check if receive chunks are addressable. */
             memchecker_call(&opal_memchecker_base_isaddressable,
                             (char *)(recvbuf)+rdispls[i]*recv_ext,
diff --git a/ompi/mpi/c/ialltoallw.c b/ompi/mpi/c/ialltoallw.c
index 980ee980e8..ececf1271f 100644
--- a/ompi/mpi/c/ialltoallw.c
+++ b/ompi/mpi/c/ialltoallw.c
@@ -60,15 +60,16 @@ int MPI_Ialltoallw(const void *sendbuf, const int sendcounts[], const int sdispl
 
         size = OMPI_COMM_IS_INTER(comm)?ompi_comm_remote_size(comm):ompi_comm_size(comm);
         for ( i = 0; i < size; i++ ) {
-            memchecker_datatype(sendtypes[i]);
+            if (MPI_IN_PLACE != sendbuf) {
+                memchecker_datatype(sendtypes[i]);
+                ompi_datatype_type_extent(sendtypes[i], &send_ext);
+                memchecker_call(&opal_memchecker_base_isdefined,
+                                (char *)(sendbuf)+sdispls[i]*send_ext,
+                                sendcounts[i], sendtypes[i]);
+            }
+
             memchecker_datatype(recvtypes[i]);
-
-            ompi_datatype_type_extent(sendtypes[i], &send_ext);
             ompi_datatype_type_extent(recvtypes[i], &recv_ext);
-
-            memchecker_call(&opal_memchecker_base_isdefined,
-                            (char *)(sendbuf)+sdispls[i]*send_ext,
-                            sendcounts[i], sendtypes[i]);
             memchecker_call(&opal_memchecker_base_isaddressable,
                             (char *)(recvbuf)+sdispls[i]*recv_ext,
                             recvcounts[i], recvtypes[i]);
diff --git a/ompi/mpi/c/ineighbor_alltoall.c b/ompi/mpi/c/ineighbor_alltoall.c
index 746697ebf7..285965f8a5 100644
--- a/ompi/mpi/c/ineighbor_alltoall.c
+++ b/ompi/mpi/c/ineighbor_alltoall.c
@@ -52,11 +52,13 @@ int MPI_Ineighbor_alltoall(const void *sendbuf, int sendcount, MPI_Datatype send
     int err;
 
     MEMCHECKER(
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-        memchecker_call(&opal_memchecker_base_isdefined, sendbuf, sendcount, sendtype);
-        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
         memchecker_comm(comm);
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            memchecker_call(&opal_memchecker_base_isdefined, (void *)sendbuf, sendcount, sendtype);
+        }
+        memchecker_datatype(recvtype);
+        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
     );
 
     if (MPI_PARAM_CHECK) {
diff --git a/ompi/mpi/c/ineighbor_alltoallv.c b/ompi/mpi/c/ineighbor_alltoallv.c
index e43c7bd244..f2d3a6d1ee 100644
--- a/ompi/mpi/c/ineighbor_alltoallv.c
+++ b/ompi/mpi/c/ineighbor_alltoallv.c
@@ -56,21 +56,25 @@ int MPI_Ineighbor_alltoallv(const void *sendbuf, const int sendcounts[], const i
         ptrdiff_t recv_ext;
         ptrdiff_t send_ext;
 
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-
-        ompi_datatype_type_extent(recvtype, &recv_ext);
-        ompi_datatype_type_extent(sendtype, &send_ext);
-
         memchecker_comm(comm);
 
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            ompi_datatype_type_extent(recvtype, &recv_ext);
+        }
+
+        memchecker_datatype(recvtype);
+        ompi_datatype_type_extent(sendtype, &send_ext);
+
         err = ompi_comm_neighbors_count(comm, &indegree, &outdegree, &weighted);
         if (MPI_SUCCESS == err) {
-            for ( i = 0; i < outdegree; i++ ) {
-                /* check if send chunks are defined. */
-                memchecker_call(&opal_memchecker_base_isdefined,
-                                (char *)(sendbuf)+sdispls[i]*send_ext,
-                                sendcounts[i], sendtype);
+            if (MPI_IN_PLACE != sendbuf) {
+                for ( i = 0; i < outdegree; i++ ) {
+                    /* check if send chunks are defined. */
+                    memchecker_call(&opal_memchecker_base_isdefined,
+                                    (char *)(sendbuf)+sdispls[i]*send_ext,
+                                    sendcounts[i], sendtype);
+                }
             }
             for ( i = 0; i < indegree; i++ ) {
                 /* check if receive chunks are addressable. */
diff --git a/ompi/mpi/c/ineighbor_alltoallw.c b/ompi/mpi/c/ineighbor_alltoallw.c
index 3cf7436387..8f82131151 100644
--- a/ompi/mpi/c/ineighbor_alltoallw.c
+++ b/ompi/mpi/c/ineighbor_alltoallw.c
@@ -60,14 +60,16 @@ int MPI_Ineighbor_alltoallw(const void *sendbuf, const int sendcounts[], const M
 
         err = ompi_comm_neighbors_count(comm, &indegree, &outdegree, &weighted);
         if (MPI_SUCCESS == err) {
-            for ( i = 0; i < outdegree; i++ ) {
-                memchecker_datatype(sendtypes[i]);
+            if (MPI_IN_PLACE != sendbuf) {
+                for ( i = 0; i < outdegree; i++ ) {
+                    memchecker_datatype(sendtypes[i]);
 
-                ompi_datatype_type_extent(sendtypes[i], &send_ext);
+                    ompi_datatype_type_extent(sendtypes[i], &send_ext);
 
-                memchecker_call(&opal_memchecker_base_isdefined,
-                                (char *)(sendbuf)+sdispls[i]*send_ext,
-                                sendcounts[i], sendtypes[i]);
+                    memchecker_call(&opal_memchecker_base_isdefined,
+                                    (char *)(sendbuf)+sdispls[i]*send_ext,
+                                    sendcounts[i], sendtypes[i]);
+                }
             }
             for ( i = 0; i < indegree; i++ ) {
                 memchecker_datatype(recvtypes[i]);
diff --git a/ompi/mpi/c/neighbor_alltoall.c b/ompi/mpi/c/neighbor_alltoall.c
index 6c23fd96a0..be1c913be8 100644
--- a/ompi/mpi/c/neighbor_alltoall.c
+++ b/ompi/mpi/c/neighbor_alltoall.c
@@ -51,11 +51,13 @@ int MPI_Neighbor_alltoall(const void *sendbuf, int sendcount, MPI_Datatype sendt
     int err;
 
     MEMCHECKER(
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-        memchecker_call(&opal_memchecker_base_isdefined, sendbuf, sendcount, sendtype);
-        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
         memchecker_comm(comm);
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            memchecker_call(&opal_memchecker_base_isdefined, (void *)sendbuf, sendcount, sendtype);
+        }
+        memchecker_datatype(recvtype);
+        memchecker_call(&opal_memchecker_base_isaddressable, recvbuf, recvcount, recvtype);
     );
 
     if (MPI_PARAM_CHECK) {
diff --git a/ompi/mpi/c/neighbor_alltoallv.c b/ompi/mpi/c/neighbor_alltoallv.c
index c29c51a5d2..deac2c32b9 100644
--- a/ompi/mpi/c/neighbor_alltoallv.c
+++ b/ompi/mpi/c/neighbor_alltoallv.c
@@ -58,21 +58,25 @@ int MPI_Neighbor_alltoallv(const void *sendbuf, const int sendcounts[], const in
         ptrdiff_t recv_ext;
         ptrdiff_t send_ext;
 
-        memchecker_datatype(sendtype);
-        memchecker_datatype(recvtype);
-
-        ompi_datatype_type_extent(recvtype, &recv_ext);
-        ompi_datatype_type_extent(sendtype, &send_ext);
-
         memchecker_comm(comm);
 
+        if (MPI_IN_PLACE != sendbuf) {
+            memchecker_datatype(sendtype);
+            ompi_datatype_type_extent(recvtype, &recv_ext);
+        }
+
+        memchecker_datatype(recvtype);
+        ompi_datatype_type_extent(sendtype, &send_ext);
+
         err = ompi_comm_neighbors_count(comm, &indegree, &outdegree, &weighted);
         if (MPI_SUCCESS == err) {
-            for ( i = 0; i < outdegree; i++ ) {
-                /* check if send chunks are defined. */
-                memchecker_call(&opal_memchecker_base_isdefined,
-                                (char *)(sendbuf)+sdispls[i]*send_ext,
-                                sendcounts[i], sendtype);
+            if (MPI_IN_PLACE != sendbuf) {
+                for ( i = 0; i < outdegree; i++ ) {
+                    /* check if send chunks are defined. */
+                    memchecker_call(&opal_memchecker_base_isdefined,
+                                    (char *)(sendbuf)+sdispls[i]*send_ext,
+                                    sendcounts[i], sendtype);
+                }
             }
             for ( i = 0; i < indegree; i++ ) {
                 /* check if receive chunks are addressable. */
diff --git a/ompi/mpi/c/neighbor_alltoallw.c b/ompi/mpi/c/neighbor_alltoallw.c
index a78ed868fe..fddd2ddb0d 100644
--- a/ompi/mpi/c/neighbor_alltoallw.c
+++ b/ompi/mpi/c/neighbor_alltoallw.c
@@ -62,14 +62,16 @@ int MPI_Neighbor_alltoallw(const void *sendbuf, const int sendcounts[], const MP
 
         err = ompi_comm_neighbors_count(comm, &indegree, &outdegree, &weighted);
         if (MPI_SUCCESS == err) {
-            for ( i = 0; i < outdegree; i++ ) {
-                memchecker_datatype(sendtypes[i]);
+            if (MPI_IN_PLACE != sendbuf) {
+                for ( i = 0; i < outdegree; i++ ) {
+                    memchecker_datatype(sendtypes[i]);
 
-                ompi_datatype_type_extent(sendtypes[i], &send_ext);
+                    ompi_datatype_type_extent(sendtypes[i], &send_ext);
 
-                memchecker_call(&opal_memchecker_base_isdefined,
-                                (char *)(sendbuf)+sdispls[i]*send_ext,
-                                sendcounts[i], sendtypes[i]);
+                    memchecker_call(&opal_memchecker_base_isdefined,
+                                    (char *)(sendbuf)+sdispls[i]*send_ext,
+                                    sendcounts[i], sendtypes[i]);
+                }
             }
             for ( i = 0; i < indegree; i++ ) {
                 memchecker_datatype(recvtypes[i]);