From: Gabriel Corona <gabriel.corona@loria.fr>
Date: Tue, 2 Sep 2014 11:29:28 +0000 (+0200)
Subject: [smpi] Allow zero-sized custom datatypes with MPI_Type_contiguous()
X-Git-Tag: v3_12~849
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/105c1b117af96a9f150b5c06ed68209a8c66e052

[smpi] Allow zero-sized custom datatypes with MPI_Type_contiguous()

MPI_Type_contiguous(0, oldtype, newtype) is valid in MPI but SMPI does
not accept it as the resulting datatype is considered invalid: SMPI
does not accept datatypes with size of 0. Fix the datatype validation
function in order to accept this.

This type of datatype is used in bcastzerotype.

bcast-NTSL is fixed as well (division by zero).
---

diff --git a/src/smpi/colls/bcast-NTSL.c b/src/smpi/colls/bcast-NTSL.c
index 7b8ede082e..c9df1a7c29 100644
--- a/src/smpi/colls/bcast-NTSL.c
+++ b/src/smpi/colls/bcast-NTSL.c
@@ -34,7 +34,7 @@ int smpi_coll_tuned_bcast_NTSL(void *buf, int count, MPI_Datatype datatype,
   int from = (rank + size - 1) % size;
 
   /* segment is segment size in number of elements (not bytes) */
-  int segment = bcast_NTSL_segment_size_in_byte / extent;
+  int segment = extent == 0 ? 1 : (bcast_NTSL_segment_size_in_byte / extent);
   segment =  segment == 0 ? 1 :segment; 
   /* pipeline length */
   int pipe_length = count / segment;
diff --git a/src/smpi/smpi_mpi_dt.c b/src/smpi/smpi_mpi_dt.c
index bedd20559a..4cd5f6454e 100644
--- a/src/smpi/smpi_mpi_dt.c
+++ b/src/smpi/smpi_mpi_dt.c
@@ -151,7 +151,7 @@ CREATE_MPI_DATATYPE(MPI_PTR, void*);
 int is_datatype_valid(MPI_Datatype datatype) {
     return datatype != MPI_DATATYPE_NULL
         && (datatype->flags & DT_FLAG_COMMITED)
-        && (smpi_datatype_size(datatype)>0);
+        && (smpi_datatype_size(datatype)>=0);
 }
 
 size_t smpi_datatype_size(MPI_Datatype datatype)