[03/46] Remove unnecessary update of NUM_SLP_USES

vect_free_slp_tree had:

  gimple *stmt;
  FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt)
    /* After transform some stmts are removed and thus their vinfo is gone.  */
    if (vinfo_for_stmt (stmt))
      {
	gcc_assert (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) > 0);
	STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))--;
      }

But after transform this update is redundant even for statements that do
exist, so it seems better to skip this loop for the final teardown.


2018-07-24  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vectorizer.h (vect_free_slp_instance): Add a final_p parameter.
	* tree-vect-slp.c (vect_free_slp_tree): Likewise.  Don't update
	STMT_VINFO_NUM_SLP_USES when it's true.
	(vect_free_slp_instance): Add a final_p parameter and pass it to
	vect_free_slp_tree.
	(vect_build_slp_tree_2): Update call to vect_free_slp_instance.
	(vect_analyze_slp_instance): Likewise.
	(vect_slp_analyze_operations): Likewise.
	(vect_slp_analyze_bb_1): Likewise.
	* tree-vectorizer.c (vec_info): Likewise.
	* tree-vect-loop.c (vect_transform_loop): Likewise.

On Tue, Jul 24, 2018 at 11:53 AM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> vect_free_slp_tree had:
>
>   gimple *stmt;
>   FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt)
>     /* After transform some stmts are removed and thus their vinfo is gone.  */
>     if (vinfo_for_stmt (stmt))
>       {
>         gcc_assert (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) > 0);
>         STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))--;
>       }
>
> But after transform this update is redundant even for statements that do
> exist, so it seems better to skip this loop for the final teardown.

OK

>
> 2018-07-24  Richard Sandiford  <richard.sandiford@arm.com>
>
> gcc/
>         * tree-vectorizer.h (vect_free_slp_instance): Add a final_p parameter.
>         * tree-vect-slp.c (vect_free_slp_tree): Likewise.  Don't update
>         STMT_VINFO_NUM_SLP_USES when it's true.
>         (vect_free_slp_instance): Add a final_p parameter and pass it to
>         vect_free_slp_tree.
>         (vect_build_slp_tree_2): Update call to vect_free_slp_instance.
>         (vect_analyze_slp_instance): Likewise.
>         (vect_slp_analyze_operations): Likewise.
>         (vect_slp_analyze_bb_1): Likewise.
>         * tree-vectorizer.c (vec_info): Likewise.
>         * tree-vect-loop.c (vect_transform_loop): Likewise.
>
> Index: gcc/tree-vectorizer.h
> ===================================================================
> --- gcc/tree-vectorizer.h       2018-07-03 10:59:30.480481417 +0100
> +++ gcc/tree-vectorizer.h       2018-07-24 10:22:09.237496975 +0100
> @@ -1634,7 +1634,7 @@ extern int vect_get_known_peeling_cost (
>  extern tree cse_and_gimplify_to_preheader (loop_vec_info, tree);
>
>  /* In tree-vect-slp.c.  */
> -extern void vect_free_slp_instance (slp_instance);
> +extern void vect_free_slp_instance (slp_instance, bool);
>  extern bool vect_transform_slp_perm_load (slp_tree, vec<tree> ,
>                                           gimple_stmt_iterator *, poly_uint64,
>                                           slp_instance, bool, unsigned *);
> Index: gcc/tree-vect-slp.c
> ===================================================================
> --- gcc/tree-vect-slp.c 2018-07-23 16:58:06.000000000 +0100
> +++ gcc/tree-vect-slp.c 2018-07-24 10:22:09.237496975 +0100
> @@ -47,25 +47,32 @@ Software Foundation; either version 3, o
>  #include "internal-fn.h"
>
>
> -/* Recursively free the memory allocated for the SLP tree rooted at NODE.  */
> +/* Recursively free the memory allocated for the SLP tree rooted at NODE.
> +   FINAL_P is true if we have vectorized the instance or if we have
> +   made a final decision not to vectorize the statements in any way.  */
>
>  static void
> -vect_free_slp_tree (slp_tree node)
> +vect_free_slp_tree (slp_tree node, bool final_p)
>  {
>    int i;
>    slp_tree child;
>
>    FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (node), i, child)
> -    vect_free_slp_tree (child);
> +    vect_free_slp_tree (child, final_p);
>
> -  gimple *stmt;
> -  FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt)
> -    /* After transform some stmts are removed and thus their vinfo is gone.  */
> -    if (vinfo_for_stmt (stmt))
> -      {
> -       gcc_assert (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) > 0);
> -       STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))--;
> -      }
> +  /* Don't update STMT_VINFO_NUM_SLP_USES if it isn't relevant.
> +     Some statements might no longer exist, after having been
> +     removed by vect_transform_stmt.  Updating the remaining
> +     statements would be redundant.  */
> +  if (!final_p)
> +    {
> +      gimple *stmt;
> +      FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (node), i, stmt)
> +       {
> +         gcc_assert (STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt)) > 0);
> +         STMT_VINFO_NUM_SLP_USES (vinfo_for_stmt (stmt))--;
> +       }
> +    }
>
>    SLP_TREE_CHILDREN (node).release ();
>    SLP_TREE_SCALAR_STMTS (node).release ();
> @@ -76,12 +83,14 @@ vect_free_slp_tree (slp_tree node)
>  }
>
>
> -/* Free the memory allocated for the SLP instance.  */
> +/* Free the memory allocated for the SLP instance.  FINAL_P is true if we
> +   have vectorized the instance or if we have made a final decision not
> +   to vectorize the statements in any way.  */
>
>  void
> -vect_free_slp_instance (slp_instance instance)
> +vect_free_slp_instance (slp_instance instance, bool final_p)
>  {
> -  vect_free_slp_tree (SLP_INSTANCE_TREE (instance));
> +  vect_free_slp_tree (SLP_INSTANCE_TREE (instance), final_p);
>    SLP_INSTANCE_LOADS (instance).release ();
>    free (instance);
>  }
> @@ -1284,7 +1293,7 @@ vect_build_slp_tree_2 (vec_info *vinfo,
>        if (++this_tree_size > max_tree_size)
>         {
>           FOR_EACH_VEC_ELT (children, j, child)
> -           vect_free_slp_tree (child);
> +           vect_free_slp_tree (child, false);
>           vect_free_oprnd_info (oprnds_info);
>           return NULL;
>         }
> @@ -1315,7 +1324,7 @@ vect_build_slp_tree_2 (vec_info *vinfo,
>                   this_loads.truncate (old_nloads);
>                   this_tree_size = old_tree_size;
>                   FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (child), j, grandchild)
> -                   vect_free_slp_tree (grandchild);
> +                   vect_free_slp_tree (grandchild, false);
>                   SLP_TREE_CHILDREN (child).truncate (0);
>
>                   dump_printf_loc (MSG_NOTE, vect_location,
> @@ -1495,7 +1504,7 @@ vect_build_slp_tree_2 (vec_info *vinfo,
>                       this_loads.truncate (old_nloads);
>                       this_tree_size = old_tree_size;
>                       FOR_EACH_VEC_ELT (SLP_TREE_CHILDREN (child), j, grandchild)
> -                       vect_free_slp_tree (grandchild);
> +                       vect_free_slp_tree (grandchild, false);
>                       SLP_TREE_CHILDREN (child).truncate (0);
>
>                       dump_printf_loc (MSG_NOTE, vect_location,
> @@ -1519,7 +1528,7 @@ vect_build_slp_tree_2 (vec_info *vinfo,
>  fail:
>        gcc_assert (child == NULL);
>        FOR_EACH_VEC_ELT (children, j, child)
> -       vect_free_slp_tree (child);
> +       vect_free_slp_tree (child, false);
>        vect_free_oprnd_info (oprnds_info);
>        return NULL;
>      }
> @@ -2036,13 +2045,13 @@ vect_analyze_slp_instance (vec_info *vin
>                                  "Build SLP failed: store group "
>                                  "size not a multiple of the vector size "
>                                  "in basic block SLP\n");
> -             vect_free_slp_tree (node);
> +             vect_free_slp_tree (node, false);
>               loads.release ();
>               return false;
>             }
>           /* Fatal mismatch.  */
>           matches[group_size / const_max_nunits * const_max_nunits] = false;
> -         vect_free_slp_tree (node);
> +         vect_free_slp_tree (node, false);
>           loads.release ();
>         }
>        else
> @@ -2102,7 +2111,7 @@ vect_analyze_slp_instance (vec_info *vin
>                       dump_gimple_stmt (MSG_MISSED_OPTIMIZATION,
>                                         TDF_SLIM, stmt, 0);
>                  }
> -              vect_free_slp_instance (new_instance);
> +             vect_free_slp_instance (new_instance, false);
>                return false;
>              }
>          }
> @@ -2133,7 +2142,7 @@ vect_analyze_slp_instance (vec_info *vin
>                 dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
>                                  "Built SLP cancelled: can use "
>                                  "load/store-lanes\n");
> -             vect_free_slp_instance (new_instance);
> +             vect_free_slp_instance (new_instance, false);
>               return false;
>             }
>         }
> @@ -2668,7 +2677,7 @@ vect_slp_analyze_operations (vec_info *v
>           dump_gimple_stmt (MSG_NOTE, TDF_SLIM,
>                             SLP_TREE_SCALAR_STMTS
>                               (SLP_INSTANCE_TREE (instance))[0], 0);
> -         vect_free_slp_instance (instance);
> +         vect_free_slp_instance (instance, false);
>            vinfo->slp_instances.ordered_remove (i);
>           cost_vec.release ();
>         }
> @@ -2947,7 +2956,7 @@ vect_slp_analyze_bb_1 (gimple_stmt_itera
>           dump_gimple_stmt (MSG_NOTE, TDF_SLIM,
>                             SLP_TREE_SCALAR_STMTS
>                               (SLP_INSTANCE_TREE (instance))[0], 0);
> -         vect_free_slp_instance (instance);
> +         vect_free_slp_instance (instance, false);
>           BB_VINFO_SLP_INSTANCES (bb_vinfo).ordered_remove (i);
>           continue;
>         }
> Index: gcc/tree-vectorizer.c
> ===================================================================
> --- gcc/tree-vectorizer.c       2018-06-27 10:27:09.894649672 +0100
> +++ gcc/tree-vectorizer.c       2018-07-24 10:22:09.237496975 +0100
> @@ -466,7 +466,7 @@ vec_info::~vec_info ()
>    unsigned int i;
>
>    FOR_EACH_VEC_ELT (slp_instances, i, instance)
> -    vect_free_slp_instance (instance);
> +    vect_free_slp_instance (instance, true);
>
>    destroy_cost_data (target_cost_data);
>    free_stmt_vec_infos (&stmt_vec_infos);
> Index: gcc/tree-vect-loop.c
> ===================================================================
> --- gcc/tree-vect-loop.c        2018-07-24 10:22:06.269523330 +0100
> +++ gcc/tree-vect-loop.c        2018-07-24 10:22:09.237496975 +0100
> @@ -2229,7 +2229,7 @@ vect_analyze_loop_2 (loop_vec_info loop_
>    LOOP_VINFO_VECT_FACTOR (loop_vinfo) = saved_vectorization_factor;
>    /* Free the SLP instances.  */
>    FOR_EACH_VEC_ELT (LOOP_VINFO_SLP_INSTANCES (loop_vinfo), j, instance)
> -    vect_free_slp_instance (instance);
> +    vect_free_slp_instance (instance, false);
>    LOOP_VINFO_SLP_INSTANCES (loop_vinfo).release ();
>    /* Reset SLP type to loop_vect on all stmts.  */
>    for (i = 0; i < LOOP_VINFO_LOOP (loop_vinfo)->num_nodes; ++i)
> @@ -8683,7 +8683,7 @@ vect_transform_loop (loop_vec_info loop_
>       won't work.  */
>    slp_instance instance;
>    FOR_EACH_VEC_ELT (LOOP_VINFO_SLP_INSTANCES (loop_vinfo), i, instance)
> -    vect_free_slp_instance (instance);
> +    vect_free_slp_instance (instance, true);
>    LOOP_VINFO_SLP_INSTANCES (loop_vinfo).release ();
>    /* Clear-up safelen field since its value is invalid after vectorization
>       since vectorized loop can have loop-carried dependencies.  */