Return faster if nothing to do.

Signed-off-by: George Bosilca <[email protected]>

Author: bosilca

opal/datatype/opal_datatype_internal.h

@@ -539,7 +539,7 @@ struct opal_datatype_t;
 #    define OPAL_DATATYPE_SAFEGUARD_POINTER(ACTPTR, LENGTH, INITPTR, PDATA, COUNT)                \
         {                                                                                         \
             unsigned char *__lower_bound = (INITPTR), *__upper_bound;                             \
-            assert(((LENGTH) != 0) && ((COUNT) != 0));                                            \
+            assert( (COUNT) != 0 );                                                               \
             __lower_bound += (PDATA)->true_lb;                                                    \
             __upper_bound = (INITPTR) + (PDATA)->true_ub +                                        \
                             ((PDATA)->ub - (PDATA)->lb) * ((COUNT) -1);                           \

opal/datatype/opal_datatype_position.c

@@ -66,8 +66,8 @@ static inline void position_single_block(opal_convertor_t *CONVERTOR, unsigned c
 }
 
 /**
- * Advance the convertors' position according. Update the pointer and the remaining space
- * accordingly.
+ * Advance the convertors' position according to account for *COUNT elements. Update
+ * the pointer and the remaining space accordingly.
  */
 static inline void position_predefined_data(opal_convertor_t *CONVERTOR, dt_elem_desc_t *ELEM,
                                             size_t *COUNT, unsigned char **POINTER, size_t *SPACE)
@@ -82,7 +82,8 @@ static inline void position_predefined_data(opal_convertor_t *CONVERTOR, dt_elem
 
     if (cando_count > *(COUNT)) {
         cando_count = *(COUNT);
-    }
+    } else if( 0 == cando_count )
+        return;
 
     if (1 == _elem->blocklen) {
         DO_DEBUG(opal_output(0,