re PR libfortran/51828 (libgfortran build warnings)

	PR libfortran/51828
	* intrinsics/unpack_generic.c (unpack_internal): Let the compiler
	know that dim > 0 to avoid warnings.

From-SVN: r204940

libgfortran/ChangeLog

+2013-11-18  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
+
+	PR libfortran/51828
+	* intrinsics/unpack_generic.c (unpack_internal): Let the compiler
+	know that dim > 0 to avoid warnings.
+
 2013-11-15  Janne Blomqvist  <jb@gcc.gnu.org>
 	    Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 

libgfortran/intrinsics/unpack_generic.c

@@ -144,6 +144,9 @@ unpack_internal (gfc_array_char *ret, const gfc_array_char *vector,
   if (empty)
     return;
 
+  /* This assert makes sure GCC knows we can access *stride[0] later.  */
+  assert (dim > 0);
+
   vstride0 = GFC_DESCRIPTOR_STRIDE_BYTES(vector,0);
   rstride0 = rstride[0];
   fstride0 = fstride[0];