[Bug target/91982] gcc.target/aarch64/sve/clastb_*.c tests failing with segfault

[prathamesh3492 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91982

--- Comment #3 from prathamesh3492 at gcc dot gnu.org ---
Probably started with r276299 ?

We segfault in vect_transform_stmt in call to dominated_by_p:

  if (!slp_node && STMT_VINFO_REDUC_DEF (orig_stmt_info)
      && STMT_VINFO_REDUC_TYPE (orig_stmt_info) != FOLD_LEFT_REDUCTION
      && is_a <gphi *> (STMT_VINFO_REDUC_DEF (orig_stmt_info)->stmt))
    {
      gphi *phi = as_a <gphi *> (STMT_VINFO_REDUC_DEF (orig_stmt_info)->stmt);
      if (dominated_by_p (CDI_DOMINATORS,
                          gimple_bb (orig_stmt_info->stmt), gimple_bb (phi)))
        {

because gimple_bb (orig_stmt_info->stmt) is NULL.

Thanks,
Prathamesh