Avoid &LOOP_VINFO_MASKS for bb vectorisation (PR 86618)

[Richard Sandiford]

r262589 introduced another instance of the bug fixed in r258131.

Tested on aarch64-linux-gnu and applied as obvious.

Richard


2018-07-24  Richard Sandiford  <richard.sandif...@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.

Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c       2018-07-24 19:03:04.000000000 +0100
+++ gcc/tree-vect-stmts.c       2018-07-24 19:03:23.521825230 +0100
@@ -3337,7 +3337,7 @@ vectorizable_call (gimple *gs, gimple_st
      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;