[Bug tree-optimization/96376] [11 regression] vect/vect-alias-check.c and vect/vect-live-5.c fail on armeb

["linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96376

Kewen Lin <linkw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |linkw at gcc dot gnu.org

--- Comment #5 from Kewen Lin <linkw at gcc dot gnu.org> ---
By checking the case vect-alias-check.c on the sparc machine, although
vectorizer does the versioning for the alignment requirement and is able to set
the misaligned flag off for misaligned DRs, it bypasses the DRs *b_20(D) and
MEM[(int *)b_20(D) + 4B], as they satisfy the condition check
!vect_relevant_for_alignment_p.

   if (aligned_access_p (dr_info)
       || !vect_relevant_for_alignment_p (dr_info))
            continue;

More specific, it's due to these two DR's steps are unchanged in the loop (b[0]
and b[1]).

   /* Scatter-gather and invariant accesses continue to address individual
     scalars, so vector-level alignment is irrelevant.  */
  if (STMT_VINFO_GATHER_SCATTER_P (stmt_info)
      || integer_zerop (DR_STEP (dr_info->dr)))
    return false;

A simple fix seems to be:

  diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
index 2b4421b5fb4..d5f52929f89 100644
--- a/gcc/tree-vect-data-refs.c
+++ b/gcc/tree-vect-data-refs.c
@@ -1186,7 +1186,7 @@ vect_update_misalignment_for_peel (dr_vec_info *dr_info,

 /* Return true if alignment is relevant for DR_INFO.  */

-static bool
+bool
 vect_relevant_for_alignment_p (dr_vec_info *dr_info)
 {
   stmt_vec_info stmt_info = dr_info->stmt;
diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index cec5c601268..8a04f55fdb1 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -2369,7 +2369,8 @@ get_load_store_type (vec_info  *vinfo, stmt_vec_info
stmt_info,
       return false;
     }

-  if (*alignment_support_scheme == dr_unaligned_unsupported)
+  if (*alignment_support_scheme == dr_unaligned_unsupported
+      && vect_relevant_for_alignment_p (STMT_VINFO_DR_INFO (stmt_info)))
     {
       if (dump_enabled_p ())
        dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 7c6de8397b3..067222ffe39 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -1935,6 +1935,7 @@ extern tree vect_get_new_ssa_name (tree, enum
vect_var_kind,
 extern tree vect_create_addr_base_for_vector_ref (vec_info *,
                                                  stmt_vec_info, gimple_seq *,
                                                  tree, tree = NULL_TREE);
+bool vect_relevant_for_alignment_p (dr_vec_info *dr_info);

 /* In tree-vect-loop.c.  */
 extern widest_int vect_iv_limit_for_partial_vectors (loop_vec_info
loop_vinfo);