https://gcc.gnu.org/g:f265e8e467ba0349f070504e342127a55b5898e2
commit r16-6537-gf265e8e467ba0349f070504e342127a55b5898e2 Author: Martin Jambor <[email protected]> Date: Wed Jan 7 11:53:14 2026 +0100 ipa-cp: Move decision to clone for all contexts to decision stage Currently, IPA-CP makes decisions to clone a function for all (known) contexts in the evaluation phase, in a separate sweep over the call graph from the decisions about cloning for values available only in certain contexts. This patch moves it to the decision stage, which requires slightly more computation at the decision stage but the benefit/cost heuristics is also likely to be slightly better because it can be calculated using the call graph edges that remain after any cloning for special contexts. Perhaps more importantly, it also allows us to do multiple decision sweeps over the call graph with different "parameters." gcc/ChangeLog: 2025-07-02 Martin Jambor <[email protected]> * ipa-prop.h (ipa_node_params): Remove member do_clone_for_all_contexts. (ipa_node_params::ipa_node_params): Do not initialize do_clone_for_all_contexts. * ipa-cp.cc (gather_context_independent_values): Remove parameter calculate_aggs, calculate them always. (estimate_local_effects): Move the decision whether to clone for all context... (decide_whether_version_node): ...here. Fix dumps. (decide_about_value): Adjust alignment in dumps. Diff: --- gcc/ipa-cp.cc | 160 ++++++++++++++++++++++++++++----------------------------- gcc/ipa-prop.h | 5 +- 2 files changed, 80 insertions(+), 85 deletions(-) diff --git a/gcc/ipa-cp.cc b/gcc/ipa-cp.cc index 7edf179a7e0f..6c2fdc8c05ba 100644 --- a/gcc/ipa-cp.cc +++ b/gcc/ipa-cp.cc @@ -3455,17 +3455,15 @@ good_cloning_opportunity_p (struct cgraph_node *node, sreal time_benefit, } /* Grow vectors in AVALS and fill them with information about values of - parameters that are known to be independent of the context. Only calculate - m_known_aggs if CALCULATE_AGGS is true. INFO describes the function. If - REMOVABLE_PARAMS_COST is non-NULL, the movement cost of all removable - parameters will be stored in it. + parameters that are known to be independent of the context. INFO describes + the function. If REMOVABLE_PARAMS_COST is non-NULL, the movement cost of + all removable parameters will be stored in it. TODO: Also grow context independent value range vectors. */ static bool gather_context_independent_values (class ipa_node_params *info, ipa_auto_call_arg_values *avals, - bool calculate_aggs, int *removable_params_cost) { int i, count = ipa_get_param_count (info); @@ -3506,8 +3504,7 @@ gather_context_independent_values (class ipa_node_params *info, if (ctxlat->is_single_const ()) avals->m_known_contexts[i] = ctxlat->values->value; - if (calculate_aggs) - ret |= push_agg_values_from_plats (plats, i, 0, &avals->m_known_aggs); + ret |= push_agg_values_from_plats (plats, i, 0, &avals->m_known_aggs); } return ret; @@ -3602,7 +3599,6 @@ estimate_local_effects (struct cgraph_node *node) { ipa_node_params *info = ipa_node_params_sum->get (node); int count = ipa_get_param_count (info); - bool always_const; int removable_params_cost; if (!count || !ipcp_versionable_function_p (node)) @@ -3612,61 +3608,7 @@ estimate_local_effects (struct cgraph_node *node) fprintf (dump_file, "\nEstimating effects for %s.\n", node->dump_name ()); ipa_auto_call_arg_values avals; - always_const = gather_context_independent_values (info, &avals, true, - &removable_params_cost); - sreal devirt_bonus = devirtualization_time_bonus (node, &avals); - if (always_const || devirt_bonus > 0 - || (removable_params_cost && clone_for_param_removal_p (node))) - { - struct caller_statistics stats; - ipa_call_estimates estimates; - - init_caller_stats (&stats); - node->call_for_symbol_thunks_and_aliases (gather_caller_stats, &stats, - false); - estimate_ipcp_clone_size_and_time (node, &avals, &estimates); - sreal time = estimates.nonspecialized_time - estimates.time; - time += devirt_bonus; - time += hint_time_bonus (node, estimates); - time += removable_params_cost; - int size = estimates.size - stats.n_calls * removable_params_cost; - - if (dump_file) - fprintf (dump_file, " - context independent values, size: %i, " - "time_benefit: %f\n", size, (time).to_double ()); - - if (size <= 0 || node->local) - { - info->do_clone_for_all_contexts = true; - - if (dump_file) - fprintf (dump_file, " Decided to specialize for all " - "known contexts, code not going to grow.\n"); - } - else if (good_cloning_opportunity_p (node, time, stats.freq_sum, - stats.count_sum, size, - stats.called_without_ipa_profile)) - { - if (size + overall_size <= get_max_overall_size (node)) - { - info->do_clone_for_all_contexts = true; - overall_size += size; - - if (dump_file) - fprintf (dump_file, " Decided to specialize for all " - "known contexts, growth (to %li) deemed " - "beneficial.\n", overall_size); - } - else if (dump_file && (dump_flags & TDF_DETAILS)) - 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)) - fprintf (dump_file, " Not cloning for all contexts because " - "!good_cloning_opportunity_p.\n"); - - } + gather_context_independent_values (info, &avals, &removable_params_cost); for (int i = 0; i < count; i++) { @@ -5915,7 +5857,7 @@ decide_about_value (struct cgraph_node *node, int index, HOST_WIDE_INT offset, return false; if (dump_file) - fprintf (dump_file, " Creating a specialized node of %s.\n", + fprintf (dump_file, " Creating a specialized node of %s.\n", node->dump_name ()); vec<tree> known_csts; @@ -5990,7 +5932,9 @@ decide_whether_version_node (struct cgraph_node *node) auto_vec <cgraph_node *, 9> self_gen_clones; ipa_auto_call_arg_values avals; - gather_context_independent_values (info, &avals, false, NULL); + int removable_params_cost; + bool ctx_independent_const + = gather_context_independent_values (info, &avals, &removable_params_cost); for (i = 0; i < count;i++) { @@ -6065,15 +6009,72 @@ decide_whether_version_node (struct cgraph_node *node) update_counts_for_self_gen_clones (node, self_gen_clones); } - if (info->do_clone_for_all_contexts) + bool do_clone_for_all_contexts = false; + sreal devirt_bonus = devirtualization_time_bonus (node, &avals); + if (ctx_independent_const || devirt_bonus > 0 + || (removable_params_cost && clone_for_param_removal_p (node))) { - if (!dbg_cnt (ipa_cp_values)) + struct caller_statistics stats; + ipa_call_estimates estimates; + + init_caller_stats (&stats); + node->call_for_symbol_thunks_and_aliases (gather_caller_stats, &stats, + false); + estimate_ipcp_clone_size_and_time (node, &avals, &estimates); + sreal time = estimates.nonspecialized_time - estimates.time; + time += devirt_bonus; + time += hint_time_bonus (node, estimates); + time += removable_params_cost; + int size = estimates.size - stats.n_calls * removable_params_cost; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, " - context independent values, size: %i, " + "time_benefit: %f\n", size, (time).to_double ()); + + if (!stats.n_calls) { - info->do_clone_for_all_contexts = false; - return ret; + if (dump_file) + fprintf (dump_file, " Not cloning for all contexts because " + "there are no callers of the original node left.\n"); + } + else if (size <= 0 || node->local) + { + if (!dbg_cnt (ipa_cp_values)) + return ret; + + do_clone_for_all_contexts = true; + if (dump_file) + fprintf (dump_file, " Decided to specialize for all " + "known contexts, code not going to grow.\n"); } + else if (good_cloning_opportunity_p (node, time, stats.freq_sum, + stats.count_sum, size, + stats.called_without_ipa_profile)) + { + if (size + overall_size <= get_max_overall_size (node)) + { + if (!dbg_cnt (ipa_cp_values)) + return ret; + + do_clone_for_all_contexts = true; + overall_size += size; + if (dump_file) + fprintf (dump_file, " Decided to specialize for all " + "known contexts, growth (to %li) deemed " + "beneficial.\n", overall_size); + } + else if (dump_file && (dump_flags & TDF_DETAILS)) + 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)) + fprintf (dump_file, " Not cloning for all contexts because " + "!good_cloning_opportunity_p.\n"); + } - struct cgraph_node *clone; + if (do_clone_for_all_contexts) + { auto_vec<cgraph_edge *> callers = node->collect_callers (); for (int i = callers.length () - 1; i >= 0; i--) @@ -6086,16 +6087,13 @@ decide_whether_version_node (struct cgraph_node *node) } if (!adjust_callers_for_value_intersection (callers, node)) - { - /* If node is not called by anyone, or all its caller edges are - self-recursive, the node is not really in use, no need to do - cloning. */ - info->do_clone_for_all_contexts = false; - return ret; - } + /* If node is not called by anyone, or all its caller edges are + self-recursive, the node is not really in use, no need to do + cloning. */ + return ret; if (dump_file) - fprintf (dump_file, " - Creating a specialized node of %s " + fprintf (dump_file, " Creating a specialized node of %s " "for all known contexts.\n", node->dump_name ()); vec<tree> known_csts = avals.m_known_vals.copy (); @@ -6111,9 +6109,9 @@ decide_whether_version_node (struct cgraph_node *node) known_contexts.release (); known_contexts = vNULL; } - clone = create_specialized_node (node, known_csts, known_contexts, - aggvals, callers); - info->do_clone_for_all_contexts = false; + struct cgraph_node *clone = create_specialized_node (node, known_csts, + known_contexts, + aggvals, callers); ipa_node_params_sum->get (clone)->is_all_contexts_clone = true; ret = true; } diff --git a/gcc/ipa-prop.h b/gcc/ipa-prop.h index 30467c02c840..173f5f466a2a 100644 --- a/gcc/ipa-prop.h +++ b/gcc/ipa-prop.h @@ -658,9 +658,6 @@ public: unsigned analysis_done : 1; /* Whether the function is enqueued in ipa-cp propagation stack. */ unsigned node_enqueued : 1; - /* Whether we should create a specialized version based on values that are - known to be constant in all contexts. */ - unsigned do_clone_for_all_contexts : 1; /* Set if this is an IPA-CP clone for all contexts. */ unsigned is_all_contexts_clone : 1; /* Node has been completely replaced by clones and will be removed after @@ -680,7 +677,7 @@ inline ipa_node_params::ipa_node_params () : descriptors (NULL), lattices (vNULL), ipcp_orig_node (NULL), known_csts (vNULL), known_contexts (vNULL), analysis_done (0), - node_enqueued (0), do_clone_for_all_contexts (0), is_all_contexts_clone (0), + node_enqueued (0), is_all_contexts_clone (0), node_dead (0), node_within_scc (0), node_is_self_scc (0), node_calling_single_call (0), versionable (0) {
