fix Darwin bootstrap.

gcc/

	* tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Cast
	MAX_OFILE_ALIGNMENT as needed.

From-SVN: r266138

gcc/ChangeLog

+2018-11-14  Iain Sandoe  <iain@sandoe.co.uk>
+
+	* tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Cast
+	MAX_OFILE_ALIGNMENT as needed.
+
 2018-11-14  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/88019

gcc/tree-vect-data-refs.c

@@ -6335,7 +6335,8 @@ vect_can_force_dr_alignment_p (const_tree decl, poly_uint64 alignment)
     return false;
 
   if (TREE_STATIC (decl))
-    return (known_le (alignment, MAX_OFILE_ALIGNMENT));
+    return (known_le (alignment,
+		      (unsigned HOST_WIDE_INT) MAX_OFILE_ALIGNMENT));
   else
     return (known_le (alignment, (unsigned HOST_WIDE_INT) MAX_STACK_ALIGNMENT));
 }