Avoid &LOOP_VINFO_MASKS for bb vectorisation (PR 86618)

r262589 introduced another instance of the bug fixed in r258131.

2018-07-23  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR tree-optimization/86618
	* tree-vect-stmts.c (vectorizable_call): Don't take the address
	of LOOP_VINFO_MASKS (loop_vinfo) when loop_vinfo is null.

From-SVN: r262951

gcc/ChangeLog

+2018-07-24  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR tree-optimization/86618
+	* tree-vect-stmts.c (vectorizable_call): Don't take the address
+	of LOOP_VINFO_MASKS (loop_vinfo) when loop_vinfo is null.
+
 2018-07-24  David Malcolm  <dmalcolm@redhat.com>
 
 	PR tree-optimization/86636

gcc/tree-vect-stmts.c

@@ -3337,7 +3337,7 @@ vectorizable_call (gimple *gs, gimple_stmt_iterator *gsi, gimple **vec_stmt,
      needs to be generated.  */
   gcc_assert (ncopies >= 1);
 
-  vec_loop_masks *masks = &LOOP_VINFO_MASKS (loop_vinfo);
+  vec_loop_masks *masks = (loop_vinfo ? &LOOP_VINFO_MASKS (loop_vinfo) : NULL);
   if (!vec_stmt) /* transformation not required.  */
     {
       STMT_VINFO_TYPE (stmt_info) = call_vec_info_type;