[01/11] Schedule SLP earlier

vect_transform_loop used to call vect_schedule_slp lazily when it
came across the first SLP statement, but it seems easier to do it
before the main loop.


2018-07-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vect-loop.c (vect_transform_loop_stmt): Remove slp_scheduled
	argument.
	(vect_transform_loop): Update calls accordingly.  Schedule SLP
	instances before the main loop, if any exist.

On Mon, Jul 30, 2018 at 1:37 PM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> vect_transform_loop used to call vect_schedule_slp lazily when it
> came across the first SLP statement, but it seems easier to do it
> before the main loop.

Indeed.

OK.
Richard.

>
> 2018-07-30  Richard Sandiford  <richard.sandiford@arm.com>
>
> gcc/
>         * tree-vect-loop.c (vect_transform_loop_stmt): Remove slp_scheduled
>         argument.
>         (vect_transform_loop): Update calls accordingly.  Schedule SLP
>         instances before the main loop, if any exist.
>
> Index: gcc/tree-vect-loop.c
> ===================================================================
> --- gcc/tree-vect-loop.c        2018-07-30 12:32:15.000000000 +0100
> +++ gcc/tree-vect-loop.c        2018-07-30 12:32:16.190624704 +0100
> @@ -8199,14 +8199,12 @@ scale_profile_for_vect_loop (struct loop
>  }
>
>  /* Vectorize STMT_INFO if relevant, inserting any new instructions before GSI.
> -   When vectorizing STMT_INFO as a store, set *SEEN_STORE to its stmt_vec_info.
> -   *SLP_SCHEDULE is a running record of whether we have called
> -   vect_schedule_slp.  */
> +   When vectorizing STMT_INFO as a store, set *SEEN_STORE to its
> +   stmt_vec_info.  */
>
>  static void
>  vect_transform_loop_stmt (loop_vec_info loop_vinfo, stmt_vec_info stmt_info,
> -                         gimple_stmt_iterator *gsi,
> -                         stmt_vec_info *seen_store, bool *slp_scheduled)
> +                         gimple_stmt_iterator *gsi, stmt_vec_info *seen_store)
>  {
>    struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo);
>    poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
> @@ -8237,24 +8235,10 @@ vect_transform_loop_stmt (loop_vec_info
>         dump_printf_loc (MSG_NOTE, vect_location, "multiple-types.\n");
>      }
>
> -  /* SLP.  Schedule all the SLP instances when the first SLP stmt is
> -     reached.  */
> -  if (slp_vect_type slptype = STMT_SLP_TYPE (stmt_info))
> -    {
> -
> -      if (!*slp_scheduled)
> -       {
> -         *slp_scheduled = true;
> -
> -         DUMP_VECT_SCOPE ("scheduling SLP instances");
> -
> -         vect_schedule_slp (loop_vinfo);
> -       }
> -
> -      /* Hybrid SLP stmts must be vectorized in addition to SLP.  */
> -      if (slptype == pure_slp)
> -       return;
> -    }
> +  /* Pure SLP statements have already been vectorized.  We still need
> +     to apply loop vectorization to hybrid SLP statements.  */
> +  if (PURE_SLP_STMT (stmt_info))
> +    return;
>
>    if (dump_enabled_p ())
>      dump_printf_loc (MSG_NOTE, vect_location, "transform statement.\n");
> @@ -8284,7 +8268,6 @@ vect_transform_loop (loop_vec_info loop_
>    tree niters_vector_mult_vf = NULL_TREE;
>    poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
>    unsigned int lowest_vf = constant_lower_bound (vf);
> -  bool slp_scheduled = false;
>    gimple *stmt;
>    bool check_profitability = false;
>    unsigned int th;
> @@ -8390,6 +8373,14 @@ vect_transform_loop (loop_vec_info loop_
>      /* This will deal with any possible peeling.  */
>      vect_prepare_for_masked_peels (loop_vinfo);
>
> +  /* Schedule the SLP instances first, then handle loop vectorization
> +     below.  */
> +  if (!loop_vinfo->slp_instances.is_empty ())
> +    {
> +      DUMP_VECT_SCOPE ("scheduling SLP instances");
> +      vect_schedule_slp (loop_vinfo);
> +    }
> +
>    /* FORNOW: the vectorizer supports only loops which body consist
>       of one basic block (header + empty latch). When the vectorizer will
>       support more involved loop forms, the order by which the BBs are
> @@ -8468,16 +8459,15 @@ vect_transform_loop (loop_vec_info loop_
>                           stmt_vec_info pat_stmt_info
>                             = loop_vinfo->lookup_stmt (gsi_stmt (subsi));
>                           vect_transform_loop_stmt (loop_vinfo, pat_stmt_info,
> -                                                   &si, &seen_store,
> -                                                   &slp_scheduled);
> +                                                   &si, &seen_store);
>                         }
>                       stmt_vec_info pat_stmt_info
>                         = STMT_VINFO_RELATED_STMT (stmt_info);
>                       vect_transform_loop_stmt (loop_vinfo, pat_stmt_info, &si,
> -                                               &seen_store, &slp_scheduled);
> +                                               &seen_store);
>                     }
>                   vect_transform_loop_stmt (loop_vinfo, stmt_info, &si,
> -                                           &seen_store, &slp_scheduled);
> +                                           &seen_store);
>                 }
>               gsi_next (&si);
>               if (seen_store)