Improve loop dumping

Hi,
we have flow_loop_dump and print_loop. While print_loop was extended to dump
stuff from loop structure we added over years (loop info), flow_loop_dump was not.
-fdump-tree-all files contains flow_loop_dump which makes it hard to see what
metadata we have attached to loop.

This patch unifies dumping of these fields from both functions.  For example for:
int a[100];
main()
{
        for (int i = 0;  i < 10; i++)
                a[i]=i;
}
we now print:
;; Loop 0
;;  header 0, latch 1
;;  depth 0, outer -1
;;  nodes: 0 1 2 3 4 5
;;
;; Loop 1
;;  header 4, latch 3
;;  depth 1, outer 0, finite_p
;;  upper_bound 10
;;  likely_upper_bound 10
;;  estimate 10
;;  iterations by profile: 10.001101 (unreliable)

finite_p, upper_bound, likely_upper_bound estimate and iterations by profile is new.

Bootstrap/regtest on x86_64 in progress. OK if it passes?

Honza

gcc/ChangeLog:

	* cfgloop.cc (flow_loop_dump): Use print_loop_info.
	* cfgloop.h (print_loop_info): Declare.
	* tree-cfg.cc (print_loop_info): Break out from ...; add
	printing of missing fields and profile
	(print_loop): ... here.

On Fri, Jul 21, 2023 at 9:57 AM Jan Hubicka via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
> we have flow_loop_dump and print_loop. While print_loop was extended to dump
> stuff from loop structure we added over years (loop info), flow_loop_dump was not.
> -fdump-tree-all files contains flow_loop_dump which makes it hard to see what
> metadata we have attached to loop.
>
> This patch unifies dumping of these fields from both functions.  For example for:
> int a[100];
> main()
> {
>         for (int i = 0;  i < 10; i++)
>                 a[i]=i;
> }
> we now print:
> ;; Loop 0
> ;;  header 0, latch 1
> ;;  depth 0, outer -1
> ;;  nodes: 0 1 2 3 4 5
> ;;
> ;; Loop 1
> ;;  header 4, latch 3
> ;;  depth 1, outer 0, finite_p
> ;;  upper_bound 10
> ;;  likely_upper_bound 10
> ;;  estimate 10
> ;;  iterations by profile: 10.001101 (unreliable)
>
> finite_p, upper_bound, likely_upper_bound estimate and iterations by profile is new.
>
> Bootstrap/regtest on x86_64 in progress. OK if it passes?

OK.

> Honza
>
> gcc/ChangeLog:
>
>         * cfgloop.cc (flow_loop_dump): Use print_loop_info.
>         * cfgloop.h (print_loop_info): Declare.
>         * tree-cfg.cc (print_loop_info): Break out from ...; add
>         printing of missing fields and profile
>         (print_loop): ... here.
>
> diff --git a/gcc/cfgloop.cc b/gcc/cfgloop.cc
> index 020e5734d95..9ca85e648a7 100644
> --- a/gcc/cfgloop.cc
> +++ b/gcc/cfgloop.cc
> @@ -135,17 +135,12 @@ flow_loop_dump (const class loop *loop, FILE *file,
>        fprintf (file, "\n");
>      }
>
> -  fprintf (file, ";;  depth %d, outer %ld\n",
> +  fprintf (file, ";;  depth %d, outer %ld",
>            loop_depth (loop), (long) (loop_outer (loop)
>                                       ? loop_outer (loop)->num : -1));
> +  print_loop_info (file, loop, ";;  ");
>
> -  bool reliable;
> -  sreal iterations;
> -  if (loop->num && expected_loop_iterations_by_profile (loop, &iterations, &reliable))
> -    fprintf (file, ";;  profile-based iteration count: %f %s\n",
> -            iterations.to_double (), reliable ? "(reliable)" : "(unreliable)");
> -
> -  fprintf (file, ";;  nodes:");
> +  fprintf (file, "\n;;  nodes:");
>    bbs = get_loop_body (loop);
>    for (i = 0; i < loop->num_nodes; i++)
>      fprintf (file, " %d", bbs[i]->index);
> diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
> index 4d2fd4b6af5..269694c7962 100644
> --- a/gcc/cfgloop.h
> +++ b/gcc/cfgloop.h
> @@ -411,6 +411,7 @@ extern unsigned expected_loop_iterations (class loop *);
>  extern rtx doloop_condition_get (rtx_insn *);
>
>  void mark_loop_for_removal (loop_p);
> +void print_loop_info (FILE *file, const class loop *loop, const char *);
>
>  /* Induction variable analysis.  */
>
> diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
> index 7ccc2a5a5a7..a6c97a04662 100644
> --- a/gcc/tree-cfg.cc
> +++ b/gcc/tree-cfg.cc
> @@ -8479,6 +8479,55 @@ print_loops_bb (FILE *file, basic_block bb, int indent, int verbosity)
>      }
>  }
>
> +/* Print loop information.  */
> +
> +void
> +print_loop_info (FILE *file, const class loop *loop, const char *prefix)
> +{
> +  if (loop->can_be_parallel)
> +    fprintf (file, ", can_be_parallel");
> +  if (loop->warned_aggressive_loop_optimizations)
> +    fprintf (file, ", warned_aggressive_loop_optimizations");
> +  if (loop->dont_vectorize)
> +    fprintf (file, ", dont_vectorize");
> +  if (loop->force_vectorize)
> +    fprintf (file, ", force_vectorize");
> +  if (loop->in_oacc_kernels_region)
> +    fprintf (file, ", in_oacc_kernels_region");
> +  if (loop->finite_p)
> +    fprintf (file, ", finite_p");
> +  if (loop->unroll)
> +    fprintf (file, "\n%sunroll %d", prefix, loop->unroll);
> +  if (loop->nb_iterations)
> +    {
> +      fprintf (file, "\n%sniter ", prefix);
> +      print_generic_expr (file, loop->nb_iterations);
> +    }
> +
> +  if (loop->any_upper_bound)
> +    {
> +      fprintf (file, "\n%supper_bound ", prefix);
> +      print_decu (loop->nb_iterations_upper_bound, file);
> +    }
> +  if (loop->any_likely_upper_bound)
> +    {
> +      fprintf (file, "\n%slikely_upper_bound ", prefix);
> +      print_decu (loop->nb_iterations_likely_upper_bound, file);
> +    }
> +
> +  if (loop->any_estimate)
> +    {
> +      fprintf (file, "\n%sestimate ", prefix);
> +      print_decu (loop->nb_iterations_estimate, file);
> +    }
> +  bool reliable;
> +  sreal iterations;
> +  if (loop->num && expected_loop_iterations_by_profile (loop, &iterations, &reliable))
> +    fprintf (file, "\n%siterations by profile: %f %s", prefix,
> +            iterations.to_double (), reliable ? "(reliable)" : "(unreliable)");
> +
> +}
> +
>  static void print_loop_and_siblings (FILE *, class loop *, int, int);
>
>  /* Pretty print LOOP on FILE, indented INDENT spaces.  Following
> @@ -8511,27 +8560,7 @@ print_loop (FILE *file, class loop *loop, int indent, int verbosity)
>      fprintf (file, ", latch = %d", loop->latch->index);
>    else
>      fprintf (file, ", multiple latches");
> -  fprintf (file, ", niter = ");
> -  print_generic_expr (file, loop->nb_iterations);
> -
> -  if (loop->any_upper_bound)
> -    {
> -      fprintf (file, ", upper_bound = ");
> -      print_decu (loop->nb_iterations_upper_bound, file);
> -    }
> -  if (loop->any_likely_upper_bound)
> -    {
> -      fprintf (file, ", likely_upper_bound = ");
> -      print_decu (loop->nb_iterations_likely_upper_bound, file);
> -    }
> -
> -  if (loop->any_estimate)
> -    {
> -      fprintf (file, ", estimate = ");
> -      print_decu (loop->nb_iterations_estimate, file);
> -    }
> -  if (loop->unroll)
> -    fprintf (file, ", unroll = %d", loop->unroll);
> +  print_loop_info (file, loop, s_indent);
>    fprintf (file, ")\n");
>
>    /* Print loop's body.  */