vect: Don't update inits for simd_lane_access DRs [PR102789]

As PR102789 shows, when vectorizer does some peelings for alignment
in prologues, function vect_update_inits_of_drs would update the
inits of some drs.  But as the failed case, we shouldn't update the
dr for simd_lane_access, it has the fixed-length storage mainly for
the main loop, the update can make the access out of bound and access
the unexpected element.

gcc/ChangeLog:

	PR tree-optimization/102789
	* tree-vect-loop-manip.c (vect_update_inits_of_drs): Do not
	update inits of simd_lane_access.

(cherry picked from commit f3dbd3f36d55178d0a9e4431043cbc950524969a)

diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index 012f48bd4870125c820049b4fc70db0ef0759bdf..d57108be5787f1685cb0131eef88397ea20d8031 100644 (file)
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -1822,7 +1822,8 @@ vect_update_inits_of_drs (loop_vec_info loop_vinfo, tree niters,
   FOR_EACH_VEC_ELT (datarefs, i, dr)
     {
       dr_vec_info *dr_info = loop_vinfo->lookup_dr (dr);
-      if (!STMT_VINFO_GATHER_SCATTER_P (dr_info->stmt))
+      if (!STMT_VINFO_GATHER_SCATTER_P (dr_info->stmt)
+         && !STMT_VINFO_SIMD_LANE_ACCESS_P (dr_info->stmt))
        vect_update_init_of_dr (dr_info, niters, code);
     }
 }