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Content-Language: en-US From: =?UTF-8?Q?Martin_Li=c5=a1ka?= To: gcc-patches@gcc.gnu.org References: <596c4483-864c-1d03-955c-69906171f037@suse.cz> Cc: Jan Hubicka In-Reply-To: <596c4483-864c-1d03-955c-69906171f037@suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-10.3 required=5.0 tests=BAYES_00, BODY_8BITS, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, NICE_REPLY_A, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Mar 2022 13:47:34 -0000 PING^1 On 1/26/22 12:11, Martin Liška wrote: > Hello. > > Right now, switch lowering does not update basic_block::count values > so that they are uninitiliazed. Moreover, I've updated probability scaling > when a more complex expansion happens. There are still some situations where > the profile is a bit imprecise, but the patch improves rapidly the current situation. > > Patch can bootstrap on x86_64-linux-gnu and survives regression tests. > > Ready to be installed? > Thanks, > Martin > >     PR tree-optimization/101301 >     PR tree-optimization/103680 > > gcc/ChangeLog: > >     * tree-switch-conversion.cc (bit_test_cluster::emit): >     Handle correctly remaining probability. >     (switch_decision_tree::try_switch_expansion): Fix BB's count >     where a cluster expansion happens. >     (switch_decision_tree::emit_cmp_and_jump_insns): Fill up also >     BB count. >     (switch_decision_tree::do_jump_if_equal): Likewise. >     (switch_decision_tree::emit_case_nodes): Handle special case >     for BT expansion which can also fallback to a default BB. >     * tree-switch-conversion.h (cluster::cluster): Add >     m_default_prob probability. > --- >  gcc/tree-switch-conversion.cc | 51 ++++++++++++++++++++++++----------- >  gcc/tree-switch-conversion.h  |  8 +++++- >  2 files changed, 43 insertions(+), 16 deletions(-) > > diff --git a/gcc/tree-switch-conversion.cc b/gcc/tree-switch-conversion.cc > index 670397c87e4..d6679e8dee3 100644 > --- a/gcc/tree-switch-conversion.cc > +++ b/gcc/tree-switch-conversion.cc > @@ -1538,10 +1538,12 @@ bit_test_cluster::emit (tree index_expr, tree index_type, >        test[k].target_bb = n->m_case_bb; >        test[k].label = n->m_case_label_expr; >        test[k].bits = 0; > +      test[k].prob = profile_probability::never (); >        count++; >      } > >        test[k].bits += n->get_range (n->get_low (), n->get_high ()); > +      test[k].prob += n->m_prob; > >        lo = tree_to_uhwi (int_const_binop (MINUS_EXPR, n->get_low (), minval)); >        if (n->get_high () == NULL_TREE) > @@ -1629,6 +1631,11 @@ bit_test_cluster::emit (tree index_expr, tree index_type, >                    /*simple=*/true, NULL_TREE, >                    /*before=*/true, GSI_SAME_STMT); > > +  profile_probability subtree_prob = m_subtree_prob; > +  profile_probability default_prob = m_default_prob; > +  if (!default_prob.initialized_p ()) > +    default_prob = m_subtree_prob.invert (); > + >    if (m_handles_entire_switch && entry_test_needed) >      { >        tree range = int_const_binop (MINUS_EXPR, maxval, minval); > @@ -1639,9 +1646,10 @@ bit_test_cluster::emit (tree index_expr, tree index_type, >                      /*simple=*/true, NULL_TREE, >                      /*before=*/true, GSI_SAME_STMT); >        tmp = fold_build2 (GT_EXPR, boolean_type_node, idx, range); > +      default_prob = default_prob.apply_scale (1, 2); >        basic_block new_bb >      = hoist_edge_and_branch_if_true (&gsi, tmp, default_bb, > -                     profile_probability::unlikely ()); > +                     default_prob); >        gsi = gsi_last_bb (new_bb); >      } > > @@ -1662,14 +1670,12 @@ bit_test_cluster::emit (tree index_expr, tree index_type, >    else >      csui = tmp; > > -  profile_probability prob = profile_probability::always (); > - >    /* for each unique set of cases: >         if (const & csui) goto target  */ >    for (k = 0; k < count; k++) >      { > -      prob = profile_probability::always ().apply_scale (test[k].bits, > -                             bt_range); > +      profile_probability prob = test[k].prob / (subtree_prob + default_prob); > +      subtree_prob -= test[k].prob; >        bt_range -= test[k].bits; >        tmp = wide_int_to_tree (word_type_node, test[k].mask); >        tmp = fold_build2 (BIT_AND_EXPR, word_type_node, csui, tmp); > @@ -1908,9 +1914,13 @@ switch_decision_tree::try_switch_expansion (vec &clusters) >        /* Emit cluster-specific switch handling.  */ >        for (unsigned i = 0; i < clusters.length (); i++) >      if (clusters[i]->get_type () != SIMPLE_CASE) > -      clusters[i]->emit (index_expr, index_type, > -                 gimple_switch_default_label (m_switch), > -                 m_default_bb, gimple_location (m_switch)); > +      { > +        edge e = single_pred_edge (clusters[i]->m_case_bb); > +        e->dest->count = e->src->count.apply_probability (e->probability); > +        clusters[i]->emit (index_expr, index_type, > +                   gimple_switch_default_label (m_switch), > +                   m_default_bb, gimple_location (m_switch)); > +      } >      } > >    fix_phi_operands_for_edges (); > @@ -2162,6 +2172,7 @@ switch_decision_tree::emit_cmp_and_jump_insns (basic_block bb, tree op0, >    edge false_edge = split_block (bb, cond); >    false_edge->flags = EDGE_FALSE_VALUE; >    false_edge->probability = prob.invert (); > +  false_edge->dest->count = bb->count.apply_probability (prob.invert ()); > >    edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); >    true_edge->probability = prob; > @@ -2192,6 +2203,7 @@ switch_decision_tree::do_jump_if_equal (basic_block bb, tree op0, tree op1, >    edge false_edge = split_block (bb, cond); >    false_edge->flags = EDGE_FALSE_VALUE; >    false_edge->probability = prob.invert (); > +  false_edge->dest->count = bb->count.apply_probability (prob.invert ()); > >    edge true_edge = make_edge (bb, label_bb, EDGE_TRUE_VALUE); >    true_edge->probability = prob; > @@ -2227,7 +2239,7 @@ switch_decision_tree::emit_case_nodes (basic_block bb, tree index, >                   node->m_c->m_case_bb, p, loc); >        /* Since this case is taken at this point, reduce its weight from >       subtree_weight.  */ > -      node->m_c->m_subtree_prob -= p; > +      node->m_c->m_subtree_prob -= node->m_c->m_prob; > >        if (node->m_left != NULL && node->m_right != NULL) >      { > @@ -2246,6 +2258,7 @@ switch_decision_tree::emit_case_nodes (basic_block bb, tree index, >             / (node->m_c->m_subtree_prob + default_prob)); >            bb = do_jump_if_equal (bb, index, node->m_right->m_c->get_low (), >                       node->m_right->m_c->m_case_bb, p, loc); > +          node->m_c->m_subtree_prob -= node->m_right->m_c->m_prob; > >            p = (node->m_left->m_c->m_prob >             / (node->m_c->m_subtree_prob + default_prob)); > @@ -2262,6 +2275,7 @@ switch_decision_tree::emit_case_nodes (basic_block bb, tree index, >            p = ((node->m_right->m_c->m_subtree_prob >              + default_prob.apply_scale (1, 2)) >             / (node->m_c->m_subtree_prob + default_prob)); > +          test_bb->count = bb->count.apply_probability (p); >            bb = emit_cmp_and_jump_insns (bb, index, node->m_c->get_high (), >                          GT_EXPR, test_bb, p, loc); >            default_prob = default_prob.apply_scale (1, 2); > @@ -2348,21 +2362,28 @@ switch_decision_tree::emit_case_nodes (basic_block bb, tree index, >       is the one to branch to.  */ >        if (node->has_child () || node->m_c->get_type () != SIMPLE_CASE) >      { > +      bool is_bt = node->m_c->get_type () == BIT_TEST; > +      int parts = is_bt ? 3 : 2; > + >        /* Branch to a label where we will handle it later.  */ >        basic_block test_bb = split_edge (single_succ_edge (bb)); >        redirect_edge_succ (single_pred_edge (test_bb), >                    single_succ_edge (bb)->dest); > > - > -       profile_probability right_prob = profile_probability::never (); > -       if (node->m_right) > -         right_prob = node->m_right->m_c->m_subtree_prob; > -      p = ((right_prob + default_prob.apply_scale (1, 2)) > +      profile_probability right_prob = profile_probability::never (); > +      if (node->m_right) > +        right_prob = node->m_right->m_c->m_subtree_prob; > +      p = ((right_prob + default_prob.apply_scale (1, parts)) >             / (node->m_c->m_subtree_prob + default_prob)); > +      test_bb->count = bb->count.apply_probability (p); > >        bb = emit_cmp_and_jump_insns (bb, index, node->m_c->get_high (), >                      GT_EXPR, test_bb, p, loc); > -      default_prob = default_prob.apply_scale (1, 2); > + > +      default_prob = default_prob.apply_scale (1, parts); > +      node->m_c->m_subtree_prob -= right_prob; > +      if (is_bt) > +        node->m_c->m_default_prob = default_prob; > >        /* Value belongs to this node or to the left-hand subtree.  */ >        p = node->m_c->m_prob / (node->m_c->m_subtree_prob + default_prob); > diff --git a/gcc/tree-switch-conversion.h b/gcc/tree-switch-conversion.h > index e969c051a05..5f3f99353ba 100644 > --- a/gcc/tree-switch-conversion.h > +++ b/gcc/tree-switch-conversion.h > @@ -102,6 +102,10 @@ public: >    /* Probability of reaching subtree rooted at this node.  */ >    profile_probability m_subtree_prob; > > +  /* Probability of default case when reaching the node. > +     It is used by bit-test right now.  */ > +  profile_probability m_default_prob; > + >  protected: >    /* Default constructor.  */ >    cluster () {} > @@ -110,7 +114,8 @@ protected: >  cluster::cluster (tree case_label_expr, basic_block case_bb, >            profile_probability prob, profile_probability subtree_prob): >    m_case_label_expr (case_label_expr), m_case_bb (case_bb), m_prob (prob), > -  m_subtree_prob (subtree_prob) > +  m_subtree_prob (subtree_prob), > +  m_default_prob (profile_probability::uninitialized ()) >  { >  } > > @@ -542,6 +547,7 @@ public: >    basic_block target_bb; >    tree label; >    int bits; > +  profile_probability prob; > >    /* Comparison function for qsort to order bit tests by decreasing >       probability of execution.  */