Re: [PATCH] Prune SCEV

[Richard Biener <richard dot guenther at gmail dot com>]

On Wed, Apr 24, 2013 at 2:18 PM, Marek Polacek <polacek@redhat.com> wrote:
> I noticed that some functions in SCEV aren't used at all.
> They were added in 4.0, but never used since.
>
> Regtested/bootstrapped on x86_64-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2013-04-24  Marek Polacek  <polacek@redhat.com>
>
>         * tree-scalar-evolution.h (analyze_scalar_evolution): Remove.
>         * tree-scalar-evolution.c (get_exit_conditions_rec): Likewise.
>         (select_loops_exit_conditions): Likewise.
>         (number_of_iterations_for_all_loops): Likewise.
>         (analyze_scalar_evolution_for_all_loop_phi_nodes): Likewise.
>         (scev_analysis): Likewise.
>
> --- gcc/tree-scalar-evolution.h.mp      2013-04-24 12:22:18.591373400 +0200
> +++ gcc/tree-scalar-evolution.h 2013-04-24 12:23:46.426701201 +0200
> @@ -34,7 +34,6 @@ extern tree analyze_scalar_evolution (st
>  extern tree instantiate_scev (basic_block, struct loop *, tree);
>  extern tree resolve_mixers (struct loop *, tree);
>  extern void gather_stats_on_scev_database (void);
> -extern void scev_analysis (void);
>  extern unsigned int scev_const_prop (void);
>  extern bool expression_expensive_p (tree);
>  extern bool simple_iv (struct loop *, struct loop *, tree, affine_iv *, bool);
> --- gcc/tree-scalar-evolution.c.mp      2013-04-24 12:22:18.587373384 +0200
> +++ gcc/tree-scalar-evolution.c 2013-04-24 12:32:54.044328690 +0200
> @@ -868,39 +868,6 @@ get_loop_exit_condition (const struct lo
>    return res;
>  }
>
> -/* Recursively determine and enqueue the exit conditions for a loop.  */
> -
> -static void
> -get_exit_conditions_rec (struct loop *loop,
> -                        vec<gimple> *exit_conditions)
> -{
> -  if (!loop)
> -    return;
> -
> -  /* Recurse on the inner loops, then on the next (sibling) loops.  */
> -  get_exit_conditions_rec (loop->inner, exit_conditions);
> -  get_exit_conditions_rec (loop->next, exit_conditions);
> -
> -  if (single_exit (loop))
> -    {
> -      gimple loop_condition = get_loop_exit_condition (loop);
> -
> -      if (loop_condition)
> -       exit_conditions->safe_push (loop_condition);
> -    }
> -}
> -
> -/* Select the candidate loop nests for the analysis.  This function
> -   initializes the EXIT_CONDITIONS array.  */
> -
> -static void
> -select_loops_exit_conditions (vec<gimple> *exit_conditions)
> -{
> -  struct loop *function_body = current_loops->tree_root;
> -
> -  get_exit_conditions_rec (function_body->inner, exit_conditions);
> -}
> -
>
>  /* Depth first search algorithm.  */
>
> @@ -2882,41 +2849,6 @@ number_of_exit_cond_executions (struct l
>    return ret;
>  }
>
> -/* One of the drivers for testing the scalar evolutions analysis.
> -   This function computes the number of iterations for all the loops
> -   from the EXIT_CONDITIONS array.  */
> -
> -static void
> -number_of_iterations_for_all_loops (vec<gimple> *exit_conditions)
> -{
> -  unsigned int i;
> -  unsigned nb_chrec_dont_know_loops = 0;
> -  unsigned nb_static_loops = 0;
> -  gimple cond;
> -
> -  FOR_EACH_VEC_ELT (*exit_conditions, i, cond)
> -    {
> -      tree res = number_of_latch_executions (loop_containing_stmt (cond));
> -      if (chrec_contains_undetermined (res))
> -       nb_chrec_dont_know_loops++;
> -      else
> -       nb_static_loops++;
> -    }
> -
> -  if (dump_file)
> -    {
> -      fprintf (dump_file, "\n(\n");
> -      fprintf (dump_file, "-----------------------------------------\n");
> -      fprintf (dump_file, "%d\tnb_chrec_dont_know_loops\n", nb_chrec_dont_know_loops);
> -      fprintf (dump_file, "%d\tnb_static_loops\n", nb_static_loops);
> -      fprintf (dump_file, "%d\tnb_total_loops\n", number_of_loops ());
> -      fprintf (dump_file, "-----------------------------------------\n");
> -      fprintf (dump_file, ")\n\n");
> -
> -      print_loops (dump_file, 3);
> -    }
> -}
> -
>
>
>  /* Counters for the stats.  */
> @@ -3028,54 +2960,6 @@ gather_chrec_stats (tree chrec, struct c
>      fprintf (dump_file, ")\n");
>  }
>
> -/* One of the drivers for testing the scalar evolutions analysis.
> -   This function analyzes the scalar evolution of all the scalars
> -   defined as loop phi nodes in one of the loops from the
> -   EXIT_CONDITIONS array.
> -
> -   TODO Optimization: A loop is in canonical form if it contains only
> -   a single scalar loop phi node.  All the other scalars that have an
> -   evolution in the loop are rewritten in function of this single
> -   index.  This allows the parallelization of the loop.  */
> -
> -static void
> -analyze_scalar_evolution_for_all_loop_phi_nodes (vec<gimple> *exit_conditions)
> -{
> -  unsigned int i;
> -  struct chrec_stats stats;
> -  gimple cond, phi;
> -  gimple_stmt_iterator psi;
> -
> -  reset_chrecs_counters (&stats);
> -
> -  FOR_EACH_VEC_ELT (*exit_conditions, i, cond)
> -    {
> -      struct loop *loop;
> -      basic_block bb;
> -      tree chrec;
> -
> -      loop = loop_containing_stmt (cond);
> -      bb = loop->header;
> -
> -      for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
> -       {
> -         phi = gsi_stmt (psi);
> -         if (!virtual_operand_p (PHI_RESULT (phi)))
> -           {
> -             chrec = instantiate_parameters
> -                       (loop,
> -                        analyze_scalar_evolution (loop, PHI_RESULT (phi)));
> -
> -             if (dump_file && (dump_flags & TDF_STATS))
> -               gather_chrec_stats (chrec, &stats);
> -           }
> -       }
> -    }
> -
> -  if (dump_file && (dump_flags & TDF_STATS))
> -    dump_chrecs_stats (dump_file, &stats);
> -}
> -
>  /* Callback for htab_traverse, gathers information on chrecs in the
>     hashtable.  */
>
> @@ -3254,23 +3138,6 @@ simple_iv (struct loop *wrto_loop, struc
>    return true;
>  }
>
> -/* Runs the analysis of scalar evolutions.  */
> -
> -void
> -scev_analysis (void)
> -{
> -  vec<gimple> exit_conditions;
> -
> -  exit_conditions.create (37);
> -  select_loops_exit_conditions (&exit_conditions);
> -
> -  if (dump_file && (dump_flags & TDF_STATS))
> -    analyze_scalar_evolution_for_all_loop_phi_nodes (&exit_conditions);
> -
> -  number_of_iterations_for_all_loops (&exit_conditions);
> -  exit_conditions.release ();
> -}
> -
>  /* Finalize the scalar evolution analysis.  */
>
>  void
>
>         Marek