On Thu, 21 May 2015, Jan Hubicka wrote:
> Hi,
> this patch extends statistics from tree-ssa-alias to also cover TBAA oracle.
> This is useful to keep track of aliasing effectivity. For example the hack
> in alias.c putting globbing all pointers to one costs about 20% of all
> answers on firefox. I.e. from 15500978 disambiguations/23744267 querries
> (with the hack removed) to 12932078 disambiguations/27256455 querries.
>
> Bootstrapped x86_64-linux, OK?
Ok with the spelling fix and the same_type_for_tbaa hunk.
Thanks,
Richard.
> Honza
>
> * alias.c (alias_stats): New static var.
> (alias_sets_conflict_p, alias_sets_must_conflict_p): Update stats.
> (dump_alias_stats_in_alias_c): New function.
> * alias.h (dump_alias_stats_in_alias_c): Declare.
> * tree-ssa-alias.c (dump_alias_stats): Call it.
> Index: alias.c
> ===================================================================
> --- alias.c (revision 223444)
> +++ alias.c (working copy)
> @@ -213,6 +213,19 @@ static int write_dependence_p (const_rtx
>
> static void memory_modified_1 (rtx, const_rtx, void *);
>
> +/* Query statistics for the different low-level disambiguators.
> + A high-level query may trigger multiple of them. */
> +
> +static struct {
> + unsigned long long num_alias_zero;
> + unsigned long long num_same_alias_set;
> + unsigned long long num_same_objects;
> + unsigned long long num_volatile;
> + unsigned long long num_dag;
> + unsigned long long num_disambiguated;
> +} alias_stats;
> +
> +
> /* Set up all info needed to perform alias analysis on memory references. */
>
> /* Returns the size in bytes of the mode of X. */
> @@ -471,13 +484,20 @@ alias_sets_conflict_p (alias_set_type se
> ase = get_alias_set_entry (set1);
> if (ase != 0
> && ase->children->get (set2))
> - return 1;
> + {
> + ++alias_stats.num_dag;
> + return 1;
> + }
>
> /* Now do the same, but with the alias sets reversed. */
> ase = get_alias_set_entry (set2);
> if (ase != 0
> && ase->children->get (set1))
> - return 1;
> + {
> + ++alias_stats.num_dag;
> + return 1;
> + }
> + ++alias_stats.num_disambiguated;
>
> /* The two alias sets are distinct and neither one is the
> child of the other. Therefore, they cannot conflict. */
> @@ -489,8 +509,16 @@ alias_sets_conflict_p (alias_set_type se
> int
> alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
> {
> - if (set1 == 0 || set2 == 0 || set1 == set2)
> - return 1;
> + if (set1 == 0 || set2 == 0)
> + {
> + ++alias_stats.num_alias_zero;
> + return 1;
> + }
> + if (set1 == set2)
> + {
> + ++alias_stats.num_same_alias_set;
> + return 1;
> + }
>
> return 0;
> }
> @@ -512,10 +540,17 @@ objects_must_conflict_p (tree t1, tree t
> return 0;
>
> /* If they are the same type, they must conflict. */
> - if (t1 == t2
> - /* Likewise if both are volatile. */
> - || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
> - return 1;
> + if (t1 == t2)
> + {
> + ++alias_stats.num_same_objects;
> + return 1;
> + }
> + /* Likewise if both are volatile. */
> + if (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))
> + {
> + ++alias_stats.num_volatile;
> + return 1;
> + }
>
> set1 = t1 ? get_alias_set (t1) : 0;
> set2 = t2 ? get_alias_set (t2) : 0;
> @@ -3043,4 +3051,21 @@ end_alias_analysis (void)
> sbitmap_free (reg_known_equiv_p);
> }
>
> +void
> +dump_alias_stats_in_alias_c (FILE *s)
> +{
> + fprintf (s, " TBAA oracle: %llu disambiguations %llu queries\n"
> + " %llu are in alias set 0\n"
> + " %llu queries asked about the same object\n"
> + " %llu quaries asked about the same alias set\n"
> + " %llu access volatile\n"
> + " %llu are dependent in the DAG\n",
> + alias_stats.num_disambiguated,
> + alias_stats.num_alias_zero + alias_stats.num_same_alias_set
> + + alias_stats.num_same_objects + alias_stats.num_volatile
> + + alias_stats.num_dag,
> + alias_stats.num_alias_zero, alias_stats.num_same_alias_set,
> + + alias_stats.num_same_objects, alias_stats.num_volatile,
> + + alias_stats.num_dag);
> +}
> #include "gt-alias.h"
> Index: alias.h
> ===================================================================
> --- alias.h (revision 223444)
> +++ alias.h (working copy)
> @@ -41,6 +41,7 @@ extern int alias_sets_conflict_p (alias_
> extern int alias_sets_must_conflict_p (alias_set_type, alias_set_type);
> extern int objects_must_conflict_p (tree, tree);
> extern int nonoverlapping_memrefs_p (const_rtx, const_rtx, bool);
> +extern void dump_alias_stats_in_alias_c (FILE *s);
> tree reference_alias_ptr_type (tree);
> bool alias_ptr_types_compatible_p (tree, tree);
>
> Index: tree-ssa-alias.c
> ===================================================================
> --- tree-ssa-alias.c (revision 223444)
> +++ tree-ssa-alias.c (working copy)
> @@ -163,6 +163,7 @@ dump_alias_stats (FILE *s)
> alias_stats.call_may_clobber_ref_p_no_alias,
> alias_stats.call_may_clobber_ref_p_no_alias
> + alias_stats.call_may_clobber_ref_p_may_alias);
> + dump_alias_stats_in_alias_c (s);
> }
>
>
> @@ -685,7 +686,12 @@ same_type_for_tbaa (tree type1, tree typ
> /* If we would have to do structural comparison bail out. */
> if (TYPE_STRUCTURAL_EQUALITY_P (type1)
> || TYPE_STRUCTURAL_EQUALITY_P (type2))
> - return -1;
> + {
> + /* The way LTO produces canonical types makes sure that everything
> + that matters has TYPE_CANONICAL set. */
> + gcc_assert (!in_lto_p);
> + return -1;
> + }
>
> /* Compare the canonical types. */
> if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2))
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham
Norton, HRB 21284 (AG Nuernberg)
