Re: [PATCH 1/2] vect: Refactor code for index == count in vect_transform_slp_perm_load_1

[Richard Biener <richard.guenther@gmail.com>]

On Wed, May 17, 2023 at 9:19 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>
> Hi Richi,
>
> on 2023/5/17 14:34, Richard Biener wrote:
> > On Wed, May 17, 2023 at 8:09 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
> >>
> >> Hi,
> >>
> >> This patch is to refactor the handlings for the case (index
> >> == count) in a loop of vect_transform_slp_perm_load_1, in
> >> order to prepare a subsequent adjustment on *nperm.  This
> >> patch doesn't have any functional changes.
> >
> > The diff is impossible to be reviewed - can you explain the
> > refactoring you have done or also attach a patch more clearly
> > showing what you change?
>
> Sorry, I should have made it more clear.
> It mainly to combine these two hunks:
>
>   if (index == count && !noop_p)
>     {
>        // A ...
>        // ++*n_perms;
>     }
>
>   if (index == count)
>     {
>        if (!analyze_only)
>          {
>             if (!noop_p)
>                // B1 ...
>
>             // B2 ...
>
>             for ...
>               {
>                  if (!noop_p)
>                     // B3 building VEC_PERM_EXPR
>                  else
>                     // B4 building nothing (no uses for B2 and its seq)
>               }
>          }
>        // B5
>     }
>
> The former can be part of the latter, so it becomes to:
>
>   if (index == count)
>     {
>        if (!noop_p)
>          {
>            // A ...
>            // ++*n_perms;
>
>            if (!analyze_only)
>              {
>                 // B1 ...
>                 // B2 ...
>                 for ...
>                    // B3 building VEC_PERM_EXPR
>              }
>          }
>        else if (!analyze_only)
>          {
>             // no B2 since no any further uses here.
>             for ...
>               // B4 building nothing
>          }
>         // B5 ...
>     }

Ah, thanks - that made reviewing easy.  1/2 is OK for trunk.

Thanks,
Richard.

> But it's mainly the basic for the subsequent patch for consistent n_perms calculation,
> the patch 2/2 is to make it further become to:
>
>   if (index == count)
>     {
>        if (!noop_p)
>          {
>            // A ...
>
>            if (!analyze_only)
>              // B1 ...
>
>            // B2 ... (trivial computations during analyze_only or not)
>
>            for ...
>              {
>                 // ++*n_perms;  (now n_perms is consistent with building VEC_PERM_EXPR)
>                 if (analyze_only)
>                    continue;
>                 // B3 building VEC_PERM_EXPR
>              }
>          }
>        else if (!analyze_only)
>          {
>             // no B2 since no any further uses here.
>             for ...
>               // B4 building nothing
>          }
>         // B5 ...
>     }
>
> BR,
> Kewen
>
>
> >
> >> Bootstrapped and regtested on x86_64-redhat-linux,
> >> aarch64-linux-gnu and powerpc64{,le}-linux-gnu.
> >>
> >> BR,
> >> Kewen
> >> -----
> >> gcc/ChangeLog:
> >>
> >>         * tree-vect-slp.cc (vect_transform_slp_perm_load_1): Refactor the
> >>         handling on the case index == count.
> >> ---
> >>  gcc/tree-vect-slp.cc | 89 ++++++++++++++++++++++----------------------
> >>  1 file changed, 44 insertions(+), 45 deletions(-)
> >>
> >> diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
> >> index 3b7a21724ec..e5c9d7e766e 100644
> >> --- a/gcc/tree-vect-slp.cc
> >> +++ b/gcc/tree-vect-slp.cc
> >> @@ -8230,59 +8230,50 @@ vect_transform_slp_perm_load_1 (vec_info *vinfo, slp_tree node,
> >>         noop_p = false;
> >>        mask[index++] = mask_element;
> >>
> >> -      if (index == count && !noop_p)
> >> +      if (index == count)
> >>         {
> >> -         indices.new_vector (mask, second_vec_index == -1 ? 1 : 2, nunits);
> >> -         if (!can_vec_perm_const_p (mode, mode, indices))
> >> +         if (!noop_p)
> >>             {
> >> -             if (dump_p)
> >> +             indices.new_vector (mask, second_vec_index == -1 ? 1 : 2, nunits);
> >> +             if (!can_vec_perm_const_p (mode, mode, indices))
> >>                 {
> >> -                 dump_printf_loc (MSG_MISSED_OPTIMIZATION,
> >> -                                  vect_location,
> >> -                                  "unsupported vect permute { ");
> >> -                 for (i = 0; i < count; ++i)
> >> +                 if (dump_p)
> >>                     {
> >> -                     dump_dec (MSG_MISSED_OPTIMIZATION, mask[i]);
> >> -                     dump_printf (MSG_MISSED_OPTIMIZATION, " ");
> >> +                     dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> >> +                                      "unsupported vect permute { ");
> >> +                     for (i = 0; i < count; ++i)
> >> +                       {
> >> +                         dump_dec (MSG_MISSED_OPTIMIZATION, mask[i]);
> >> +                         dump_printf (MSG_MISSED_OPTIMIZATION, " ");
> >> +                       }
> >> +                     dump_printf (MSG_MISSED_OPTIMIZATION, "}\n");
> >>                     }
> >> -                 dump_printf (MSG_MISSED_OPTIMIZATION, "}\n");
> >> +                 gcc_assert (analyze_only);
> >> +                 return false;
> >>                 }
> >> -             gcc_assert (analyze_only);
> >> -             return false;
> >> -           }
> >>
> >> -         ++*n_perms;
> >> -       }
> >> +             ++*n_perms;
> >>
> >> -      if (index == count)
> >> -       {
> >> -         if (!analyze_only)
> >> -           {
> >> -             tree mask_vec = NULL_TREE;
> >> -
> >> -             if (! noop_p)
> >> -               mask_vec = vect_gen_perm_mask_checked (vectype, indices);
> >> +             if (!analyze_only)
> >> +               {
> >> +                 tree mask_vec = vect_gen_perm_mask_checked (vectype, indices);
> >>
> >> -             if (second_vec_index == -1)
> >> -               second_vec_index = first_vec_index;
> >> +                 if (second_vec_index == -1)
> >> +                   second_vec_index = first_vec_index;
> >>
> >> -             for (unsigned int ri = 0; ri < nvectors_per_build; ++ri)
> >> -               {
> >> -                 /* Generate the permute statement if necessary.  */
> >> -                 tree first_vec = dr_chain[first_vec_index + ri];
> >> -                 tree second_vec = dr_chain[second_vec_index + ri];
> >> -                 gimple *perm_stmt;
> >> -                 if (! noop_p)
> >> +                 for (unsigned int ri = 0; ri < nvectors_per_build; ++ri)
> >>                     {
> >> -                     gassign *stmt = as_a <gassign *> (stmt_info->stmt);
> >> +                     /* Generate the permute statement if necessary.  */
> >> +                     tree first_vec = dr_chain[first_vec_index + ri];
> >> +                     tree second_vec = dr_chain[second_vec_index + ri];
> >> +                     gassign *stmt = as_a<gassign *> (stmt_info->stmt);
> >>                       tree perm_dest
> >>                         = vect_create_destination_var (gimple_assign_lhs (stmt),
> >>                                                        vectype);
> >>                       perm_dest = make_ssa_name (perm_dest);
> >> -                     perm_stmt
> >> +                     gimple *perm_stmt
> >>                         = gimple_build_assign (perm_dest, VEC_PERM_EXPR,
> >> -                                              first_vec, second_vec,
> >> -                                              mask_vec);
> >> +                                              first_vec, second_vec, mask_vec);
> >>                       vect_finish_stmt_generation (vinfo, stmt_info, perm_stmt,
> >>                                                    gsi);
> >>                       if (dce_chain)
> >> @@ -8290,15 +8281,23 @@ vect_transform_slp_perm_load_1 (vec_info *vinfo, slp_tree node,
> >>                           bitmap_set_bit (used_defs, first_vec_index + ri);
> >>                           bitmap_set_bit (used_defs, second_vec_index + ri);
> >>                         }
> >> +
> >> +                     /* Store the vector statement in NODE.  */
> >> +                     SLP_TREE_VEC_STMTS (node) [vect_stmts_counter++]
> >> +                       = perm_stmt;
> >>                     }
> >> -                 else
> >> -                   {
> >> -                     /* If mask was NULL_TREE generate the requested
> >> -                        identity transform.  */
> >> -                     perm_stmt = SSA_NAME_DEF_STMT (first_vec);
> >> -                     if (dce_chain)
> >> -                       bitmap_set_bit (used_defs, first_vec_index + ri);
> >> -                   }
> >> +               }
> >> +           }
> >> +         else if (!analyze_only)
> >> +           {
> >> +             for (unsigned int ri = 0; ri < nvectors_per_build; ++ri)
> >> +               {
> >> +                 tree first_vec = dr_chain[first_vec_index + ri];
> >> +                 /* If mask was NULL_TREE generate the requested
> >> +                    identity transform.  */
> >> +                 gimple *perm_stmt = SSA_NAME_DEF_STMT (first_vec);
> >> +                 if (dce_chain)
> >> +                   bitmap_set_bit (used_defs, first_vec_index + ri);
> >>
> >>                   /* Store the vector statement in NODE.  */
> >>                   SLP_TREE_VEC_STMTS (node)[vect_stmts_counter++] = perm_stmt;
> >> --
> >> 2.39.1
>
>