Hi Martin,
This change (r280099) is causing a major performance regression on exchange2 in
SPEC2017 dropping the benchmark by more than 30%.
It seems the parameters no longer do anything. i.e. -flto --param
ipa-cp-eval-threshold=1 --param ipa-cp-unit-growth=80 doesn't have any effect
anymore.
Thanks,
Tamar
> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org <gcc-patches-ow...@gcc.gnu.org>
> On Behalf Of Martin Jambor
> Sent: Wednesday, January 8, 2020 4:14 PM
> To: Martin Liška <mli...@suse.cz>; gcc-patches@gcc.gnu.org
> Cc: hubi...@ucw.cz; Richard Biener <richard.guent...@gmail.com>
> Subject: Re: [PATCH] Add Optimization for various IPA parameters.
>
> Hi,
>
> On Fri, Jan 03 2020, Martin Liška wrote:
> > Hi.
> >
> > This is similar transformation for IPA passes. This time, one needs to
> > use opt_for_fn in order to get the right parameter values.
> >
> > @Martin, Honza:
> > There are last few remaining parameters which should use
> > opt_for_fn:
> >
> > param_ipa_cp_unit_growth
>
> So as we discussed, picking this one from one particular node is not what one
> would expect to happen, but inlining does it too and so anyway:
>
>
> IPA-CP: Always access param_ipcp_unit_growth through opt_for_fn
>
> 2020-01-07 Martin Jambor <mjam...@suse.cz>
>
> * params.opt (param_ipcp_unit_growth): Mark as Optimization.
> * ipa-cp.c (max_new_size): Removed.
> (orig_overall_size): New variable.
> (get_max_overall_size): New function.
> (estimate_local_effects): Use it. Adjust dump.
> (decide_about_value): Likewise.
> (ipcp_propagate_stage): Do not calculate max_new_size, just store
> orig_overall_size. Adjust dump.
> (ipa_cp_c_finalize): Clear orig_overall_size instead of max_new_size.
> ---
> gcc/ipa-cp.c | 39 ++++++++++++++++++++++++++-------------
> gcc/params.opt | 2 +-
> 2 files changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c index 9e20e278eff..c2572e3e0e8
> 100644
> --- a/gcc/ipa-cp.c
> +++ b/gcc/ipa-cp.c
> @@ -375,7 +375,7 @@ static profile_count max_count;
>
> /* Original overall size of the program. */
>
> -static long overall_size, max_new_size;
> +static long overall_size, orig_overall_size;
>
> /* Node name to unique clone suffix number map. */ static
> hash_map<const char *, unsigned> *clone_num_suffixes; @@ -3395,6
> +3395,23 @@ perform_estimation_of_a_value (cgraph_node *node,
> vec<tree> known_csts,
> val->local_size_cost = size;
> }
>
> +/* Get the overall limit oof growth based on parameters extracted from
> growth.
> + it does not really make sense to mix functions with different overall
> growth
> + limits but it is possible and if it happens, we do not want to select one
> + limit at random. */
> +
> +static long
> +get_max_overall_size (cgraph_node *node) {
> + long max_new_size = orig_overall_size;
> + long large_unit = opt_for_fn (node->decl, param_large_unit_insns);
> + if (max_new_size < large_unit)
> + max_new_size = large_unit;
> + int unit_growth = opt_for_fn (node->decl, param_ipcp_unit_growth);
> + max_new_size += max_new_size * unit_growth / 100 + 1;
> + return max_new_size;
> +}
> +
> /* Iterate over known values of parameters of NODE and estimate the local
> effects in terms of time and size they have. */
>
> @@ -3457,7 +3474,7 @@ estimate_local_effects (struct cgraph_node *node)
> stats.freq_sum, stats.count_sum,
> size))
> {
> - if (size + overall_size <= max_new_size)
> + if (size + overall_size <= get_max_overall_size (node))
> {
> info->do_clone_for_all_contexts = true;
> overall_size += size;
> @@ -3467,8 +3484,8 @@ estimate_local_effects (struct cgraph_node *node)
> "known contexts, growth deemed beneficial.\n");
> }
> else if (dump_file && (dump_flags & TDF_DETAILS))
> - fprintf (dump_file, " Not cloning for all contexts because "
> - "max_new_size would be reached with %li.\n",
> + fprintf (dump_file, " Not cloning for all contexts because "
> + "maximum unit size would be reached with %li.\n",
> size + overall_size);
> }
> else if (dump_file && (dump_flags & TDF_DETAILS)) @@ -3860,14
> +3877,10 @@ ipcp_propagate_stage (class ipa_topo_info *topo)
> max_count = max_count.max (node->count.ipa ());
> }
>
> - max_new_size = overall_size;
> - if (max_new_size < param_large_unit_insns)
> - max_new_size = param_large_unit_insns;
> - max_new_size += max_new_size * param_ipcp_unit_growth / 100 + 1;
> + orig_overall_size = overall_size;
>
> if (dump_file)
> - fprintf (dump_file, "\noverall_size: %li, max_new_size: %li\n",
> - overall_size, max_new_size);
> + fprintf (dump_file, "\noverall_size: %li\n", overall_size);
>
> propagate_constants_topo (topo);
> if (flag_checking)
> @@ -5380,11 +5393,11 @@ decide_about_value (struct cgraph_node *node,
> int index, HOST_WIDE_INT offset,
> perhaps_add_new_callers (node, val);
> return false;
> }
> - else if (val->local_size_cost + overall_size > max_new_size)
> + else if (val->local_size_cost + overall_size > get_max_overall_size
> + (node))
> {
> if (dump_file && (dump_flags & TDF_DETAILS))
> fprintf (dump_file, " Ignoring candidate value because "
> - "max_new_size would be reached with %li.\n",
> + "maximum unit size would be reached with %li.\n",
> val->local_size_cost + overall_size);
> return false;
> }
> @@ -5928,6 +5941,6 @@ ipa_cp_c_finalize (void) {
> max_count = profile_count::uninitialized ();
> overall_size = 0;
> - max_new_size = 0;
> + orig_overall_size = 0;
> ipcp_free_transformation_sum ();
> }
> diff --git a/gcc/params.opt b/gcc/params.opt index
> d5f0d9a69ce..3cd6d7d481d 100644
> --- a/gcc/params.opt
> +++ b/gcc/params.opt
> @@ -243,7 +243,7 @@ Common Joined UInteger
> Var(param_ipa_sra_ptr_growth_factor) Init(2) Param Maximum allowed
> growth of number and total size of new parameters that ipa-sra replaces a
> pointer to an aggregate with.
>
> -param=ipcp-unit-growth=
> -Common Joined UInteger Var(param_ipcp_unit_growth) Init(10) Param
> +Common Joined UInteger Var(param_ipcp_unit_growth) Optimization
> +Init(10) Param
> How much can given compilation unit grow because of the interprocedural
> constant propagation (in percent).
>
> -param=ira-loop-reserved-regs=
> --
> 2.24.1
