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1556 lines
66 KiB
C++
1556 lines
66 KiB
C++
/*
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* Copyright (c) 2011, 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "memory/allocation.hpp"
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#include "opto/loopnode.hpp"
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#include "opto/addnode.hpp"
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#include "opto/callnode.hpp"
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#include "opto/castnode.hpp"
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#include "opto/connode.hpp"
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#include "opto/convertnode.hpp"
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#include "opto/loopnode.hpp"
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#include "opto/matcher.hpp"
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#include "opto/mulnode.hpp"
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#include "opto/opaquenode.hpp"
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#include "opto/predicates.hpp"
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#include "opto/rootnode.hpp"
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#include "opto/subnode.hpp"
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#include <fenv.h>
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#include <math.h>
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/*
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* The general idea of Loop Predication is to hoist a check inside a loop body by inserting a Hoisted Check Predicate with
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* an uncommon trap on the entry path to the loop. The old check inside the loop can be eliminated. If the condition of
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* the Hoisted Check Predicate fails at runtime, we'll execute the uncommon trap to avoid entering the loop which misses
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* the check. Loop Predication can currently remove array range checks and loop invariant checks (such as null checks).
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*
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* On top of these predicates added by Loop Predication, there are other kinds of predicates. A detailed description
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* about all predicates can be found in predicates.hpp.
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*/
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//-------------------------------register_control-------------------------
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void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred, bool update_body) {
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assert(n->is_CFG(), "msust be control node");
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_igvn.register_new_node_with_optimizer(n);
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if (update_body) {
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loop->_body.push(n);
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}
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set_loop(n, loop);
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// When called from beautify_loops() idom is not constructed yet.
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if (_idom != nullptr) {
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set_idom(n, pred, dom_depth(pred));
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}
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}
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//------------------------------create_new_if_for_predicate------------------------
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// create a new if above the uct_if_pattern for the predicate to be promoted.
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//
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// before after
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// ---------- ----------
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// ctrl ctrl
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// | |
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// | |
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// v v
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// iff new_iff
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// / \ / \
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// / \ / \
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// v v v v
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// uncommon_proj cont_proj if_uct if_cont
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// \ | | | |
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// \ | | | |
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// v v v | v
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// rgn loop | iff
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// | | / \
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// | | / \
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// v | v v
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// uncommon_trap | uncommon_proj cont_proj
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// \ \ | |
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// \ \ | |
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// v v v v
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// rgn loop
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// |
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// |
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// v
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// uncommon_trap
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//
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//
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// We will create a region to guard the uct call if there is no one there.
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// The continuation projection (if_cont) of the new_iff is returned which
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// is an IfTrue projection. This code is also used to clone predicates to cloned loops.
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IfProjNode* PhaseIdealLoop::create_new_if_for_predicate(ParsePredicateSuccessProj* parse_predicate_proj, Node* new_entry,
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Deoptimization::DeoptReason reason,
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const int opcode, const bool rewire_uncommon_proj_phi_inputs) {
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assert(parse_predicate_proj->is_uncommon_trap_if_pattern(reason), "must be a uct if pattern!");
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ParsePredicateNode* parse_predicate = parse_predicate_proj->in(0)->as_ParsePredicate();
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ProjNode* uncommon_proj = parse_predicate->proj_out(false);
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Node* uct_region = uncommon_proj->unique_ctrl_out();
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assert(uct_region->is_Region() || uct_region->is_Call(), "must be a region or call uct");
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uint proj_index = 1; // region's edge corresponding to uncommon_proj
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if (!uct_region->is_Region()) { // create a region to guard the call
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assert(uct_region->is_Call(), "must be call uct");
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CallNode* call = uct_region->as_Call();
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IdealLoopTree* loop = get_loop(call);
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uct_region = new RegionNode(1);
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Node* uncommon_proj_orig = uncommon_proj;
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uncommon_proj = uncommon_proj->clone()->as_Proj();
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register_control(uncommon_proj, loop, parse_predicate);
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uct_region->add_req(uncommon_proj);
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register_control(uct_region, loop, uncommon_proj);
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_igvn.replace_input_of(call, 0, uct_region);
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// When called from beautify_loops() idom is not constructed yet.
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if (_idom != nullptr) {
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set_idom(call, uct_region, dom_depth(uct_region));
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}
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// Move nodes pinned on the projection or whose control is set to
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// the projection to the region.
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lazy_replace(uncommon_proj_orig, uct_region);
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} else {
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// Find region's edge corresponding to uncommon_proj
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for (; proj_index < uct_region->req(); proj_index++)
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if (uct_region->in(proj_index) == uncommon_proj) break;
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assert(proj_index < uct_region->req(), "sanity");
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}
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Node* entry = parse_predicate->in(0);
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if (new_entry != nullptr) {
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// Cloning the predicate to new location.
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entry = new_entry;
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}
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// Create new_iff
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IdealLoopTree* lp = get_loop(entry);
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IfNode* new_iff = nullptr;
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switch (opcode) {
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case Op_If:
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new_iff = new IfNode(entry, parse_predicate->in(1), parse_predicate->_prob, parse_predicate->_fcnt);
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break;
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case Op_RangeCheck:
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new_iff = new RangeCheckNode(entry, parse_predicate->in(1), parse_predicate->_prob, parse_predicate->_fcnt);
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break;
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case Op_ParsePredicate:
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new_iff = new ParsePredicateNode(entry, reason, &_igvn);
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break;
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default:
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fatal("no other If variant here");
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}
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register_control(new_iff, lp, entry);
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IfProjNode* if_cont = new IfTrueNode(new_iff);
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IfProjNode* if_uct = new IfFalseNode(new_iff);
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register_control(if_cont, lp, new_iff);
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register_control(if_uct, get_loop(uct_region), new_iff);
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_igvn.add_input_to(uct_region, if_uct);
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// If rgn has phis add new edges which has the same
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// value as on original uncommon_proj pass.
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assert(uct_region->in(uct_region->req() - 1) == if_uct, "new edge should be last");
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bool has_phi = false;
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for (DUIterator_Fast imax, i = uct_region->fast_outs(imax); i < imax; i++) {
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Node* use = uct_region->fast_out(i);
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if (use->is_Phi() && use->outcnt() > 0) {
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assert(use->in(0) == uct_region, "");
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_igvn.rehash_node_delayed(use);
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Node* phi_input = use->in(proj_index);
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if (uncommon_proj->outcnt() > 1 && !phi_input->is_CFG() && !phi_input->is_Phi() && get_ctrl(phi_input) == uncommon_proj) {
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// There are some control dependent nodes on the uncommon projection. We cannot simply reuse these data nodes.
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// We either need to rewire them from the old uncommon projection to the newly created uncommon proj (if the old
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// If is dying) or clone them and update their control (if the old If is not dying).
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if (rewire_uncommon_proj_phi_inputs) {
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// Replace phi input for the old uncommon projection with TOP as the If is dying anyways. Reuse the old data
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// nodes by simply updating control inputs and ctrl.
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_igvn.replace_input_of(use, proj_index, C->top());
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set_ctrl_of_nodes_with_same_ctrl(phi_input, uncommon_proj, if_uct);
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} else {
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phi_input = clone_nodes_with_same_ctrl(phi_input, uncommon_proj, if_uct);
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}
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}
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use->add_req(phi_input);
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has_phi = true;
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}
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}
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assert(!has_phi || uct_region->req() > 3, "no phis when region is created");
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if (new_entry == nullptr) {
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// Attach if_cont to iff
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_igvn.replace_input_of(parse_predicate, 0, if_cont);
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if (_idom != nullptr) {
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set_idom(parse_predicate, if_cont, dom_depth(parse_predicate));
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}
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}
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// When called from beautify_loops() idom is not constructed yet.
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if (_idom != nullptr) {
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Node* ridom = idom(uct_region);
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Node* nrdom = dom_lca_internal(ridom, new_iff);
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set_idom(uct_region, nrdom, dom_depth(uct_region));
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}
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return if_cont->as_IfProj();
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}
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// Update ctrl and control inputs of all data nodes starting from 'node' to 'new_ctrl' which have 'old_ctrl' as
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// current ctrl.
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void PhaseIdealLoop::set_ctrl_of_nodes_with_same_ctrl(Node* node, ProjNode* old_ctrl, Node* new_ctrl) {
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Unique_Node_List nodes_with_same_ctrl = find_nodes_with_same_ctrl(node, old_ctrl);
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for (uint j = 0; j < nodes_with_same_ctrl.size(); j++) {
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Node* next = nodes_with_same_ctrl[j];
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if (next->in(0) == old_ctrl) {
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_igvn.replace_input_of(next, 0, new_ctrl);
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}
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set_ctrl(next, new_ctrl);
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}
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}
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// Recursively find all input nodes with the same ctrl.
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Unique_Node_List PhaseIdealLoop::find_nodes_with_same_ctrl(Node* node, const ProjNode* ctrl) {
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Unique_Node_List nodes_with_same_ctrl;
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nodes_with_same_ctrl.push(node);
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for (uint j = 0; j < nodes_with_same_ctrl.size(); j++) {
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Node* next = nodes_with_same_ctrl[j];
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for (uint k = 1; k < next->req(); k++) {
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Node* in = next->in(k);
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if (!in->is_Phi() && get_ctrl(in) == ctrl) {
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nodes_with_same_ctrl.push(in);
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}
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}
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}
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return nodes_with_same_ctrl;
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}
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// Clone all nodes with the same ctrl as 'old_ctrl' starting from 'node' by following its inputs. Rewire the cloned nodes
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// to 'new_ctrl'. Returns the clone of 'node'.
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Node* PhaseIdealLoop::clone_nodes_with_same_ctrl(Node* node, ProjNode* old_ctrl, Node* new_ctrl) {
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DEBUG_ONLY(uint last_idx = C->unique();)
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Unique_Node_List nodes_with_same_ctrl = find_nodes_with_same_ctrl(node, old_ctrl);
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Dict old_new_mapping = clone_nodes(nodes_with_same_ctrl); // Cloned but not rewired, yet
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rewire_cloned_nodes_to_ctrl(old_ctrl, new_ctrl, nodes_with_same_ctrl, old_new_mapping);
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Node* clone_phi_input = static_cast<Node*>(old_new_mapping[node]);
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assert(clone_phi_input != nullptr && clone_phi_input->_idx >= last_idx, "must exist and be a proper clone");
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return clone_phi_input;
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}
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// Clone all the nodes on 'list_to_clone' and return an old->new mapping.
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Dict PhaseIdealLoop::clone_nodes(const Node_List& list_to_clone) {
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Dict old_new_mapping(cmpkey, hashkey);
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for (uint i = 0; i < list_to_clone.size(); i++) {
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Node* next = list_to_clone[i];
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Node* clone = next->clone();
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_igvn.register_new_node_with_optimizer(clone);
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old_new_mapping.Insert(next, clone);
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}
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return old_new_mapping;
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}
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// Rewire inputs of the unprocessed cloned nodes (inputs are not updated, yet, and still point to the old nodes) by
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// using the old_new_mapping.
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void PhaseIdealLoop::rewire_cloned_nodes_to_ctrl(const ProjNode* old_ctrl, Node* new_ctrl,
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const Node_List& nodes_with_same_ctrl, const Dict& old_new_mapping) {
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for (uint i = 0; i < nodes_with_same_ctrl.size(); i++) {
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Node* next = nodes_with_same_ctrl[i];
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Node* clone = static_cast<Node*>(old_new_mapping[next]);
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if (next->in(0) == old_ctrl) {
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// All data nodes with a control input to the uncommon projection in the chain need to be rewired to the new uncommon
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// projection (could not only be the last data node in the chain but also, for example, a DivNode within the chain).
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_igvn.replace_input_of(clone, 0, new_ctrl);
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set_ctrl(clone, new_ctrl);
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}
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rewire_inputs_of_clones_to_clones(new_ctrl, clone, old_new_mapping, next);
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}
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}
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// Rewire the inputs of the cloned nodes to the old nodes to the new clones.
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void PhaseIdealLoop::rewire_inputs_of_clones_to_clones(Node* new_ctrl, Node* clone, const Dict& old_new_mapping,
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const Node* next) {
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for (uint i = 1; i < next->req(); i++) {
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Node* in = next->in(i);
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if (!in->is_Phi()) {
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assert(!in->is_CFG(), "must be data node");
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Node* in_clone = static_cast<Node*>(old_new_mapping[in]);
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if (in_clone != nullptr) {
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_igvn.replace_input_of(clone, i, in_clone);
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set_ctrl(clone, new_ctrl);
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}
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}
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}
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}
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IfProjNode* PhaseIdealLoop::clone_parse_predicate_to_unswitched_loop(ParsePredicateSuccessProj* parse_predicate_proj,
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Node* new_entry, Deoptimization::DeoptReason reason,
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const bool slow_loop) {
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IfProjNode* new_predicate_proj = create_new_if_for_predicate(parse_predicate_proj, new_entry, reason, Op_ParsePredicate,
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slow_loop);
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assert(new_predicate_proj->is_IfTrue(), "the success projection of a Parse Predicate is a true projection");
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ParsePredicateNode* parse_predicate = new_predicate_proj->in(0)->as_ParsePredicate();
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return new_predicate_proj;
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}
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// Clones Assertion Predicates to both unswitched loops starting at 'old_predicate_proj' by following its control inputs.
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// It also rewires the control edges of data nodes with dependencies in the loop from the old predicates to the new
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// cloned predicates.
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void PhaseIdealLoop::clone_assertion_predicates_to_unswitched_loop(IdealLoopTree* loop, const Node_List& old_new,
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Deoptimization::DeoptReason reason,
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IfProjNode* old_predicate_proj,
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ParsePredicateSuccessProj* fast_loop_parse_predicate_proj,
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ParsePredicateSuccessProj* slow_loop_parse_predicate_proj) {
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assert(fast_loop_parse_predicate_proj->in(0)->is_ParsePredicate() &&
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slow_loop_parse_predicate_proj->in(0)->is_ParsePredicate(), "sanity check");
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// Only need to clone range check predicates as those can be changed and duplicated by inserting pre/main/post loops
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// and doing loop unrolling. Push the original predicates on a list to later process them in reverse order to keep the
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// original predicate order.
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Unique_Node_List list;
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get_assertion_predicates(old_predicate_proj, list);
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Node_List to_process;
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IfNode* iff = old_predicate_proj->in(0)->as_If();
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IfProjNode* uncommon_proj = iff->proj_out(1 - old_predicate_proj->as_Proj()->_con)->as_IfProj();
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// Process in reverse order such that 'create_new_if_for_predicate' can be used in
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// 'clone_assertion_predicate_for_unswitched_loops' and the original order is maintained.
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for (int i = list.size() - 1; i >= 0; i--) {
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Node* predicate = list.at(i);
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assert(predicate->in(0)->is_If(), "must be If node");
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iff = predicate->in(0)->as_If();
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assert(predicate->is_Proj() && predicate->as_Proj()->is_IfProj(), "predicate must be a projection of an if node");
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IfProjNode* predicate_proj = predicate->as_IfProj();
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IfProjNode* fast_proj = clone_assertion_predicate_for_unswitched_loops(iff, predicate_proj, reason, fast_loop_parse_predicate_proj);
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assert(assertion_predicate_has_loop_opaque_node(fast_proj->in(0)->as_If()), "must find Assertion Predicate for fast loop");
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IfProjNode* slow_proj = clone_assertion_predicate_for_unswitched_loops(iff, predicate_proj, reason, slow_loop_parse_predicate_proj);
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assert(assertion_predicate_has_loop_opaque_node(slow_proj->in(0)->as_If()), "must find Assertion Predicate for slow loop");
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// Update control dependent data nodes.
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for (DUIterator j = predicate->outs(); predicate->has_out(j); j++) {
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Node* fast_node = predicate->out(j);
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if (loop->is_member(get_loop(ctrl_or_self(fast_node)))) {
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assert(fast_node->in(0) == predicate, "only control edge");
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Node* slow_node = old_new[fast_node->_idx];
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assert(slow_node->in(0) == predicate, "only control edge");
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_igvn.replace_input_of(fast_node, 0, fast_proj);
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to_process.push(slow_node);
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--j;
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}
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}
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// Have to delay updates to the slow loop so uses of predicate are not modified while we iterate on them.
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while (to_process.size() > 0) {
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Node* slow_node = to_process.pop();
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_igvn.replace_input_of(slow_node, 0, slow_proj);
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}
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}
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}
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// Put all Assertion Predicate projections on a list, starting at 'predicate' and going up in the tree. If 'get_opaque'
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// is set, then the Opaque4 nodes of the Assertion Predicates are put on the list instead of the projections.
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void PhaseIdealLoop::get_assertion_predicates(Node* predicate, Unique_Node_List& list, bool get_opaque) {
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ParsePredicateNode* parse_predicate = predicate->in(0)->as_ParsePredicate();
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ProjNode* uncommon_proj = parse_predicate->proj_out(1 - predicate->as_Proj()->_con);
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Node* rgn = uncommon_proj->unique_ctrl_out();
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assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct");
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predicate = parse_predicate->in(0);
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while (predicate != nullptr && predicate->is_Proj() && predicate->in(0)->is_If()) {
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IfNode* iff = predicate->in(0)->as_If();
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uncommon_proj = iff->proj_out(1 - predicate->as_Proj()->_con);
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if (uncommon_proj->unique_ctrl_out() != rgn) {
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break;
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}
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if (iff->in(1)->Opcode() == Op_Opaque4 && assertion_predicate_has_loop_opaque_node(iff)) {
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if (get_opaque) {
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// Collect the predicate Opaque4 node.
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list.push(iff->in(1));
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} else {
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// Collect the predicate projection.
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list.push(predicate);
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}
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}
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predicate = predicate->in(0)->in(0);
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}
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}
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// Clone an Assertion Predicate for an unswitched loop. OpaqueLoopInit and OpaqueLoopStride nodes are cloned and uncommon
|
|
// traps are kept for the predicate (a Halt node is used later when creating pre/main/post loops and copying this cloned
|
|
// predicate again).
|
|
IfProjNode* PhaseIdealLoop::clone_assertion_predicate_for_unswitched_loops(Node* iff, IfProjNode* predicate,
|
|
Deoptimization::DeoptReason reason,
|
|
ParsePredicateSuccessProj* parse_predicate_proj) {
|
|
Node* bol = create_bool_from_template_assertion_predicate(iff, nullptr, nullptr, parse_predicate_proj);
|
|
IfProjNode* if_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr, reason, iff->Opcode(), false);
|
|
_igvn.replace_input_of(if_proj->in(0), 1, bol);
|
|
_igvn.replace_input_of(parse_predicate_proj->in(0), 0, if_proj);
|
|
set_idom(parse_predicate_proj->in(0), if_proj, dom_depth(if_proj));
|
|
return if_proj;
|
|
}
|
|
|
|
// Clone the old Parse Predicates and Assertion Predicates before the unswitch If to the unswitched loops after the
|
|
// unswitch If.
|
|
void PhaseIdealLoop::clone_parse_and_assertion_predicates_to_unswitched_loop(IdealLoopTree* loop, Node_List& old_new,
|
|
IfProjNode*& iffast_pred, IfProjNode*& ifslow_pred) {
|
|
LoopNode* head = loop->_head->as_Loop();
|
|
Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
|
|
|
|
const Predicates predicates(entry);
|
|
clone_loop_predication_predicates_to_unswitched_loop(loop, old_new, predicates.loop_predicate_block(),
|
|
Deoptimization::Reason_predicate, iffast_pred, ifslow_pred);
|
|
clone_loop_predication_predicates_to_unswitched_loop(loop, old_new, predicates.profiled_loop_predicate_block(),
|
|
Deoptimization::Reason_profile_predicate, iffast_pred, ifslow_pred);
|
|
|
|
const PredicateBlock* loop_limit_check_predicate_block = predicates.loop_limit_check_predicate_block();
|
|
if (loop_limit_check_predicate_block->has_parse_predicate() && !head->is_CountedLoop()) {
|
|
// Don't clone the Loop Limit Check Parse Predicate if we already have a counted loop (a Loop Limit Check Predicate
|
|
// is only created when converting a LoopNode to a CountedLoopNode).
|
|
clone_parse_predicate_to_unswitched_loops(loop_limit_check_predicate_block, Deoptimization::Reason_loop_limit_check,
|
|
iffast_pred, ifslow_pred);
|
|
}
|
|
}
|
|
|
|
// Clone the Parse Predicate and Template Assertion Predicates of a Loop Predication related Predicate Block.
|
|
void PhaseIdealLoop::clone_loop_predication_predicates_to_unswitched_loop(IdealLoopTree* loop, const Node_List& old_new,
|
|
const PredicateBlock* predicate_block,
|
|
Deoptimization::DeoptReason reason,
|
|
IfProjNode*& iffast_pred,
|
|
IfProjNode*& ifslow_pred) {
|
|
if (predicate_block->has_parse_predicate()) {
|
|
// We currently only clone Assertion Predicates if there are Parse Predicates. This is not entirely correct and will
|
|
// be changed with the complete fix for Assertion Predicates.
|
|
clone_parse_predicate_to_unswitched_loops(predicate_block, reason, iffast_pred, ifslow_pred);
|
|
assert(iffast_pred->in(0)->is_ParsePredicate() && ifslow_pred->in(0)->is_ParsePredicate(),
|
|
"must be success projections of the cloned Parse Predicates");
|
|
clone_assertion_predicates_to_unswitched_loop(loop, old_new, reason, predicate_block->parse_predicate_success_proj(),
|
|
iffast_pred->as_IfTrue(), ifslow_pred->as_IfTrue());
|
|
}
|
|
}
|
|
|
|
void PhaseIdealLoop::clone_parse_predicate_to_unswitched_loops(const PredicateBlock* predicate_block,
|
|
Deoptimization::DeoptReason reason,
|
|
IfProjNode*& iffast_pred, IfProjNode*& ifslow_pred) {
|
|
assert(predicate_block->has_parse_predicate(), "must have parse predicate");
|
|
ParsePredicateSuccessProj* parse_predicate_proj = predicate_block->parse_predicate_success_proj();
|
|
iffast_pred = clone_parse_predicate_to_unswitched_loop(parse_predicate_proj, iffast_pred, reason, false);
|
|
check_cloned_parse_predicate_for_unswitching(iffast_pred, true);
|
|
|
|
ifslow_pred = clone_parse_predicate_to_unswitched_loop(parse_predicate_proj, ifslow_pred, reason, true);
|
|
check_cloned_parse_predicate_for_unswitching(ifslow_pred, false);
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
void PhaseIdealLoop::check_cloned_parse_predicate_for_unswitching(const Node* new_entry, const bool is_fast_loop) {
|
|
assert(new_entry != nullptr, "IfTrue or IfFalse after clone predicate");
|
|
if (TraceLoopPredicate) {
|
|
tty->print("Parse Predicate cloned to %s loop: ", is_fast_loop ? "fast" : "slow");
|
|
new_entry->in(0)->dump();
|
|
}
|
|
}
|
|
#endif
|
|
|
|
//------------------------------Invariance-----------------------------------
|
|
// Helper class for loop_predication_impl to compute invariance on the fly and
|
|
// clone invariants.
|
|
class Invariance : public StackObj {
|
|
VectorSet _visited, _invariant;
|
|
Node_Stack _stack;
|
|
VectorSet _clone_visited;
|
|
Node_List _old_new; // map of old to new (clone)
|
|
IdealLoopTree* _lpt;
|
|
PhaseIdealLoop* _phase;
|
|
Node* _data_dependency_on; // The projection into the loop on which data nodes are dependent or null otherwise
|
|
|
|
// Helper function to set up the invariance for invariance computation
|
|
// If n is a known invariant, set up directly. Otherwise, look up the
|
|
// the possibility to push n onto the stack for further processing.
|
|
void visit(Node* use, Node* n) {
|
|
if (_lpt->is_invariant(n)) { // known invariant
|
|
_invariant.set(n->_idx);
|
|
} else if (!n->is_CFG()) {
|
|
Node *n_ctrl = _phase->ctrl_or_self(n);
|
|
Node *u_ctrl = _phase->ctrl_or_self(use); // self if use is a CFG
|
|
if (_phase->is_dominator(n_ctrl, u_ctrl)) {
|
|
_stack.push(n, n->in(0) == nullptr ? 1 : 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Compute invariance for "the_node" and (possibly) all its inputs recursively
|
|
// on the fly
|
|
void compute_invariance(Node* n) {
|
|
assert(_visited.test(n->_idx), "must be");
|
|
visit(n, n);
|
|
while (_stack.is_nonempty()) {
|
|
Node* n = _stack.node();
|
|
uint idx = _stack.index();
|
|
if (idx == n->req()) { // all inputs are processed
|
|
_stack.pop();
|
|
// n is invariant if it's inputs are all invariant
|
|
bool all_inputs_invariant = true;
|
|
for (uint i = 0; i < n->req(); i++) {
|
|
Node* in = n->in(i);
|
|
if (in == nullptr) continue;
|
|
assert(_visited.test(in->_idx), "must have visited input");
|
|
if (!_invariant.test(in->_idx)) { // bad guy
|
|
all_inputs_invariant = false;
|
|
break;
|
|
}
|
|
}
|
|
if (all_inputs_invariant) {
|
|
// If n's control is a predicate that was moved out of the
|
|
// loop, it was marked invariant but n is only invariant if
|
|
// it depends only on that test. Otherwise, unless that test
|
|
// is out of the loop, it's not invariant.
|
|
if (n->is_CFG() || n->depends_only_on_test() || n->in(0) == nullptr || !_phase->is_member(_lpt, n->in(0))) {
|
|
_invariant.set(n->_idx); // I am a invariant too
|
|
}
|
|
}
|
|
} else { // process next input
|
|
_stack.set_index(idx + 1);
|
|
Node* m = n->in(idx);
|
|
if (m != nullptr && !_visited.test_set(m->_idx)) {
|
|
visit(n, m);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Helper function to set up _old_new map for clone_nodes.
|
|
// If n is a known invariant, set up directly ("clone" of n == n).
|
|
// Otherwise, push n onto the stack for real cloning.
|
|
void clone_visit(Node* n) {
|
|
assert(_invariant.test(n->_idx), "must be invariant");
|
|
if (_lpt->is_invariant(n)) { // known invariant
|
|
_old_new.map(n->_idx, n);
|
|
} else { // to be cloned
|
|
assert(!n->is_CFG(), "should not see CFG here");
|
|
_stack.push(n, n->in(0) == nullptr ? 1 : 0);
|
|
}
|
|
}
|
|
|
|
// Clone "n" and (possibly) all its inputs recursively
|
|
void clone_nodes(Node* n, Node* ctrl) {
|
|
clone_visit(n);
|
|
while (_stack.is_nonempty()) {
|
|
Node* n = _stack.node();
|
|
uint idx = _stack.index();
|
|
if (idx == n->req()) { // all inputs processed, clone n!
|
|
_stack.pop();
|
|
// clone invariant node
|
|
Node* n_cl = n->clone();
|
|
_old_new.map(n->_idx, n_cl);
|
|
_phase->register_new_node(n_cl, ctrl);
|
|
for (uint i = 0; i < n->req(); i++) {
|
|
Node* in = n_cl->in(i);
|
|
if (in == nullptr) continue;
|
|
n_cl->set_req(i, _old_new[in->_idx]);
|
|
}
|
|
} else { // process next input
|
|
_stack.set_index(idx + 1);
|
|
Node* m = n->in(idx);
|
|
if (m != nullptr && !_clone_visited.test_set(m->_idx)) {
|
|
clone_visit(m); // visit the input
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public:
|
|
Invariance(Arena* area, IdealLoopTree* lpt) :
|
|
_visited(area), _invariant(area),
|
|
_stack(area, 10 /* guess */),
|
|
_clone_visited(area), _old_new(area),
|
|
_lpt(lpt), _phase(lpt->_phase),
|
|
_data_dependency_on(nullptr)
|
|
{
|
|
LoopNode* head = _lpt->_head->as_Loop();
|
|
Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
|
|
if (entry->outcnt() != 1) {
|
|
// If a node is pinned between the predicates and the loop
|
|
// entry, we won't be able to move any node in the loop that
|
|
// depends on it above it in a predicate. Mark all those nodes
|
|
// as non-loop-invariant.
|
|
// Loop predication could create new nodes for which the below
|
|
// invariant information is missing. Mark the 'entry' node to
|
|
// later check again if a node needs to be treated as non-loop-
|
|
// invariant as well.
|
|
_data_dependency_on = entry;
|
|
Unique_Node_List wq;
|
|
wq.push(entry);
|
|
for (uint next = 0; next < wq.size(); ++next) {
|
|
Node *n = wq.at(next);
|
|
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
|
|
Node* u = n->fast_out(i);
|
|
if (!u->is_CFG()) {
|
|
Node* c = _phase->get_ctrl(u);
|
|
if (_lpt->is_member(_phase->get_loop(c)) || _phase->is_dominator(c, head)) {
|
|
_visited.set(u->_idx);
|
|
wq.push(u);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Did we explicitly mark some nodes non-loop-invariant? If so, return the entry node on which some data nodes
|
|
// are dependent that prevent loop predication. Otherwise, return null.
|
|
Node* data_dependency_on() {
|
|
return _data_dependency_on;
|
|
}
|
|
|
|
// Map old to n for invariance computation and clone
|
|
void map_ctrl(Node* old, Node* n) {
|
|
assert(old->is_CFG() && n->is_CFG(), "must be");
|
|
_old_new.map(old->_idx, n); // "clone" of old is n
|
|
_invariant.set(old->_idx); // old is invariant
|
|
_clone_visited.set(old->_idx);
|
|
}
|
|
|
|
// Driver function to compute invariance
|
|
bool is_invariant(Node* n) {
|
|
if (!_visited.test_set(n->_idx))
|
|
compute_invariance(n);
|
|
return (_invariant.test(n->_idx) != 0);
|
|
}
|
|
|
|
// Driver function to clone invariant
|
|
Node* clone(Node* n, Node* ctrl) {
|
|
assert(ctrl->is_CFG(), "must be");
|
|
assert(_invariant.test(n->_idx), "must be an invariant");
|
|
if (!_clone_visited.test(n->_idx))
|
|
clone_nodes(n, ctrl);
|
|
return _old_new[n->_idx];
|
|
}
|
|
};
|
|
|
|
//------------------------------is_range_check_if -----------------------------------
|
|
// Returns true if the predicate of iff is in "scale*iv + offset u< load_range(ptr)" format
|
|
// Note: this function is particularly designed for loop predication. We require load_range
|
|
// and offset to be loop invariant computed on the fly by "invar"
|
|
bool IdealLoopTree::is_range_check_if(IfProjNode* if_success_proj, PhaseIdealLoop *phase, BasicType bt, Node *iv, Node *&range,
|
|
Node *&offset, jlong &scale) const {
|
|
IfNode* iff = if_success_proj->in(0)->as_If();
|
|
if (!is_loop_exit(iff)) {
|
|
return false;
|
|
}
|
|
if (!iff->in(1)->is_Bool()) {
|
|
return false;
|
|
}
|
|
const BoolNode *bol = iff->in(1)->as_Bool();
|
|
if (bol->_test._test != BoolTest::lt || if_success_proj->is_IfFalse()) {
|
|
// We don't have the required range check pattern:
|
|
// if (scale*iv + offset <u limit) {
|
|
//
|
|
// } else {
|
|
// trap();
|
|
// }
|
|
//
|
|
// Having the trap on the true projection:
|
|
// if (scale*iv + offset <u limit) {
|
|
// trap();
|
|
// }
|
|
//
|
|
// is not correct. We would need to flip the test to get the expected "trap on false path" pattern:
|
|
// if (scale*iv + offset >=u limit) {
|
|
//
|
|
// } else {
|
|
// trap();
|
|
// }
|
|
//
|
|
// If we create a Range Check Predicate for this wrong pattern, it could succeed at runtime (i.e. true for the
|
|
// value of "scale*iv + offset" in the first loop iteration and true for the value of "scale*iv + offset" in the
|
|
// last loop iteration) while the check to be hoisted could fail in other loop iterations.
|
|
//
|
|
// Example:
|
|
// Loop: "for (int i = -1; i < 1000; i++)"
|
|
// init = "scale*iv + offset" in the first loop iteration = 1*-1 + 0 = -1
|
|
// last = "scale*iv + offset" in the last loop iteration = 1*999 + 0 = 999
|
|
// limit = 100
|
|
//
|
|
// Range Check Predicate is always true:
|
|
// init >=u limit && last >=u limit <=>
|
|
// -1 >=u 100 && 999 >= u 100
|
|
//
|
|
// But for 0 <= x < 100: x >=u 100 is false.
|
|
// We would wrongly skip the branch with the trap() and possibly miss to execute some other statements inside that
|
|
// trap() branch.
|
|
return false;
|
|
}
|
|
if (!bol->in(1)->is_Cmp()) {
|
|
return false;
|
|
}
|
|
const CmpNode *cmp = bol->in(1)->as_Cmp();
|
|
if (cmp->Opcode() != Op_Cmp_unsigned(bt)) {
|
|
return false;
|
|
}
|
|
range = cmp->in(2);
|
|
if (range->Opcode() != Op_LoadRange) {
|
|
const TypeInteger* tinteger = phase->_igvn.type(range)->isa_integer(bt);
|
|
if (tinteger == nullptr || tinteger->empty() || tinteger->lo_as_long() < 0) {
|
|
// Allow predication on positive values that aren't LoadRanges.
|
|
// This allows optimization of loops where the length of the
|
|
// array is a known value and doesn't need to be loaded back
|
|
// from the array.
|
|
return false;
|
|
}
|
|
} else {
|
|
assert(bt == T_INT, "no LoadRange for longs");
|
|
}
|
|
scale = 0;
|
|
offset = nullptr;
|
|
if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, bt, &scale, &offset)) {
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool IdealLoopTree::is_range_check_if(IfProjNode* if_success_proj, PhaseIdealLoop *phase, Invariance& invar DEBUG_ONLY(COMMA ProjNode *predicate_proj)) const {
|
|
Node* range = nullptr;
|
|
Node* offset = nullptr;
|
|
jlong scale = 0;
|
|
Node* iv = _head->as_BaseCountedLoop()->phi();
|
|
Compile* C = Compile::current();
|
|
const uint old_unique_idx = C->unique();
|
|
if (!is_range_check_if(if_success_proj, phase, T_INT, iv, range, offset, scale)) {
|
|
return false;
|
|
}
|
|
if (!invar.is_invariant(range)) {
|
|
return false;
|
|
}
|
|
if (offset != nullptr) {
|
|
if (!invar.is_invariant(offset)) { // offset must be invariant
|
|
return false;
|
|
}
|
|
Node* data_dependency_on = invar.data_dependency_on();
|
|
if (data_dependency_on != nullptr && old_unique_idx < C->unique()) {
|
|
// 'offset' node was newly created in is_range_check_if(). Check that it does not depend on the entry projection
|
|
// into the loop. If it does, we cannot perform loop predication (see Invariant::Invariant()).
|
|
assert(!offset->is_CFG(), "offset must be a data node");
|
|
if (_phase->get_ctrl(offset) == data_dependency_on) {
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
#ifdef ASSERT
|
|
if (offset && phase->has_ctrl(offset)) {
|
|
Node* offset_ctrl = phase->get_ctrl(offset);
|
|
if (phase->get_loop(predicate_proj) == phase->get_loop(offset_ctrl) &&
|
|
phase->is_dominator(predicate_proj, offset_ctrl)) {
|
|
// If the control of offset is loop predication promoted by previous pass,
|
|
// then it will lead to cyclic dependency.
|
|
// Previously promoted loop predication is in the same loop of predication
|
|
// point.
|
|
// This situation can occur when pinning nodes too conservatively - can we do better?
|
|
assert(false, "cyclic dependency prevents range check elimination, idx: offset %d, offset_ctrl %d, predicate_proj %d",
|
|
offset->_idx, offset_ctrl->_idx, predicate_proj->_idx);
|
|
}
|
|
}
|
|
#endif
|
|
return true;
|
|
}
|
|
|
|
//------------------------------rc_predicate-----------------------------------
|
|
// Create a range check predicate
|
|
//
|
|
// for (i = init; i < limit; i += stride) {
|
|
// a[scale*i+offset]
|
|
// }
|
|
//
|
|
// Compute max(scale*i + offset) for init <= i < limit and build the predicate
|
|
// as "max(scale*i + offset) u< a.length".
|
|
//
|
|
// There are two cases for max(scale*i + offset):
|
|
// (1) stride*scale > 0
|
|
// max(scale*i + offset) = scale*(limit-stride) + offset
|
|
// (2) stride*scale < 0
|
|
// max(scale*i + offset) = scale*init + offset
|
|
BoolNode* PhaseIdealLoop::rc_predicate(IdealLoopTree* loop, Node* ctrl, int scale, Node* offset, Node* init,
|
|
Node* limit, jint stride, Node* range, bool upper, bool& overflow) {
|
|
jint con_limit = (limit != nullptr && limit->is_Con()) ? limit->get_int() : 0;
|
|
jint con_init = init->is_Con() ? init->get_int() : 0;
|
|
jint con_offset = offset->is_Con() ? offset->get_int() : 0;
|
|
|
|
stringStream* predString = nullptr;
|
|
if (TraceLoopPredicate) {
|
|
predString = new (mtCompiler) stringStream();
|
|
predString->print("rc_predicate ");
|
|
}
|
|
|
|
overflow = false;
|
|
Node* max_idx_expr = nullptr;
|
|
const TypeInt* idx_type = TypeInt::INT;
|
|
if ((stride > 0) == (scale > 0) == upper) {
|
|
guarantee(limit != nullptr, "sanity");
|
|
if (TraceLoopPredicate) {
|
|
if (limit->is_Con()) {
|
|
predString->print("(%d ", con_limit);
|
|
} else {
|
|
predString->print("(limit ");
|
|
}
|
|
predString->print("- %d) ", stride);
|
|
}
|
|
// Check if (limit - stride) may overflow
|
|
const TypeInt* limit_type = _igvn.type(limit)->isa_int();
|
|
jint limit_lo = limit_type->_lo;
|
|
jint limit_hi = limit_type->_hi;
|
|
if ((stride > 0 && (java_subtract(limit_lo, stride) < limit_lo)) ||
|
|
(stride < 0 && (java_subtract(limit_hi, stride) > limit_hi))) {
|
|
// No overflow possible
|
|
ConINode* con_stride = _igvn.intcon(stride);
|
|
set_ctrl(con_stride, C->root());
|
|
max_idx_expr = new SubINode(limit, con_stride);
|
|
idx_type = TypeInt::make(limit_lo - stride, limit_hi - stride, limit_type->_widen);
|
|
} else {
|
|
// May overflow
|
|
overflow = true;
|
|
limit = new ConvI2LNode(limit);
|
|
register_new_node(limit, ctrl);
|
|
ConLNode* con_stride = _igvn.longcon(stride);
|
|
set_ctrl(con_stride, C->root());
|
|
max_idx_expr = new SubLNode(limit, con_stride);
|
|
}
|
|
register_new_node(max_idx_expr, ctrl);
|
|
} else {
|
|
if (TraceLoopPredicate) {
|
|
if (init->is_Con()) {
|
|
predString->print("%d ", con_init);
|
|
} else {
|
|
predString->print("init ");
|
|
}
|
|
}
|
|
idx_type = _igvn.type(init)->isa_int();
|
|
max_idx_expr = init;
|
|
}
|
|
|
|
if (scale != 1) {
|
|
ConNode* con_scale = _igvn.intcon(scale);
|
|
set_ctrl(con_scale, C->root());
|
|
if (TraceLoopPredicate) {
|
|
predString->print("* %d ", scale);
|
|
}
|
|
// Check if (scale * max_idx_expr) may overflow
|
|
const TypeInt* scale_type = TypeInt::make(scale);
|
|
MulINode* mul = new MulINode(max_idx_expr, con_scale);
|
|
idx_type = (TypeInt*)mul->mul_ring(idx_type, scale_type);
|
|
if (overflow || TypeInt::INT->higher_equal(idx_type)) {
|
|
// May overflow
|
|
mul->destruct(&_igvn);
|
|
if (!overflow) {
|
|
max_idx_expr = new ConvI2LNode(max_idx_expr);
|
|
register_new_node(max_idx_expr, ctrl);
|
|
}
|
|
overflow = true;
|
|
con_scale = _igvn.longcon(scale);
|
|
set_ctrl(con_scale, C->root());
|
|
max_idx_expr = new MulLNode(max_idx_expr, con_scale);
|
|
} else {
|
|
// No overflow possible
|
|
max_idx_expr = mul;
|
|
}
|
|
register_new_node(max_idx_expr, ctrl);
|
|
}
|
|
|
|
if (offset && (!offset->is_Con() || con_offset != 0)){
|
|
if (TraceLoopPredicate) {
|
|
if (offset->is_Con()) {
|
|
predString->print("+ %d ", con_offset);
|
|
} else {
|
|
predString->print("+ offset");
|
|
}
|
|
}
|
|
// Check if (max_idx_expr + offset) may overflow
|
|
const TypeInt* offset_type = _igvn.type(offset)->isa_int();
|
|
jint lo = java_add(idx_type->_lo, offset_type->_lo);
|
|
jint hi = java_add(idx_type->_hi, offset_type->_hi);
|
|
if (overflow || (lo > hi) ||
|
|
((idx_type->_lo & offset_type->_lo) < 0 && lo >= 0) ||
|
|
((~(idx_type->_hi | offset_type->_hi)) < 0 && hi < 0)) {
|
|
// May overflow
|
|
if (!overflow) {
|
|
max_idx_expr = new ConvI2LNode(max_idx_expr);
|
|
register_new_node(max_idx_expr, ctrl);
|
|
}
|
|
overflow = true;
|
|
offset = new ConvI2LNode(offset);
|
|
register_new_node(offset, ctrl);
|
|
max_idx_expr = new AddLNode(max_idx_expr, offset);
|
|
} else {
|
|
// No overflow possible
|
|
max_idx_expr = new AddINode(max_idx_expr, offset);
|
|
}
|
|
register_new_node(max_idx_expr, ctrl);
|
|
}
|
|
|
|
CmpNode* cmp = nullptr;
|
|
if (overflow) {
|
|
// Integer expressions may overflow, do long comparison
|
|
range = new ConvI2LNode(range);
|
|
register_new_node(range, ctrl);
|
|
cmp = new CmpULNode(max_idx_expr, range);
|
|
} else {
|
|
cmp = new CmpUNode(max_idx_expr, range);
|
|
}
|
|
register_new_node(cmp, ctrl);
|
|
BoolNode* bol = new BoolNode(cmp, BoolTest::lt);
|
|
register_new_node(bol, ctrl);
|
|
|
|
if (TraceLoopPredicate) {
|
|
predString->print_cr("<u range");
|
|
tty->print("%s", predString->base());
|
|
delete predString;
|
|
}
|
|
return bol;
|
|
}
|
|
|
|
// Should loop predication look not only in the path from tail to head
|
|
// but also in branches of the loop body?
|
|
bool PhaseIdealLoop::loop_predication_should_follow_branches(IdealLoopTree* loop, float& loop_trip_cnt) {
|
|
if (!UseProfiledLoopPredicate) {
|
|
return false;
|
|
}
|
|
|
|
LoopNode* head = loop->_head->as_Loop();
|
|
bool follow_branches = true;
|
|
IdealLoopTree* l = loop->_child;
|
|
// For leaf loops and loops with a single inner loop
|
|
while (l != nullptr && follow_branches) {
|
|
IdealLoopTree* child = l;
|
|
if (child->_child != nullptr &&
|
|
child->_head->is_OuterStripMinedLoop()) {
|
|
assert(child->_child->_next == nullptr, "only one inner loop for strip mined loop");
|
|
assert(child->_child->_head->is_CountedLoop() && child->_child->_head->as_CountedLoop()->is_strip_mined(), "inner loop should be strip mined");
|
|
child = child->_child;
|
|
}
|
|
if (child->_child != nullptr || child->_irreducible) {
|
|
follow_branches = false;
|
|
}
|
|
l = l->_next;
|
|
}
|
|
if (follow_branches) {
|
|
loop->compute_profile_trip_cnt(this);
|
|
if (head->is_profile_trip_failed()) {
|
|
follow_branches = false;
|
|
} else {
|
|
loop_trip_cnt = head->profile_trip_cnt();
|
|
if (head->is_CountedLoop()) {
|
|
CountedLoopNode* cl = head->as_CountedLoop();
|
|
if (cl->phi() != nullptr) {
|
|
const TypeInt* t = _igvn.type(cl->phi())->is_int();
|
|
float worst_case_trip_cnt = ((float)t->_hi - t->_lo) / ABS(cl->stride_con());
|
|
if (worst_case_trip_cnt < loop_trip_cnt) {
|
|
loop_trip_cnt = worst_case_trip_cnt;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return follow_branches;
|
|
}
|
|
|
|
float PathFrequency::to(Node* n) {
|
|
// post order walk on the CFG graph from n to _dom
|
|
IdealLoopTree* loop = _phase->get_loop(_dom);
|
|
Node* c = n;
|
|
for (;;) {
|
|
assert(_phase->get_loop(c) == loop, "have to be in the same loop");
|
|
if (c == _dom || _freqs.at_grow(c->_idx, -1) >= 0) {
|
|
float f = c == _dom ? 1 : _freqs.at(c->_idx);
|
|
Node* prev = c;
|
|
while (_stack.size() > 0 && prev == c) {
|
|
Node* n = _stack.node();
|
|
if (!n->is_Region()) {
|
|
if (_phase->get_loop(n) != _phase->get_loop(n->in(0))) {
|
|
// Found an inner loop: compute frequency of reaching this
|
|
// exit from the loop head by looking at the number of
|
|
// times each loop exit was taken
|
|
IdealLoopTree* inner_loop = _phase->get_loop(n->in(0));
|
|
LoopNode* inner_head = inner_loop->_head->as_Loop();
|
|
assert(_phase->get_loop(n) == loop, "only 1 inner loop");
|
|
if (inner_head->is_OuterStripMinedLoop()) {
|
|
inner_head->verify_strip_mined(1);
|
|
if (n->in(0) == inner_head->in(LoopNode::LoopBackControl)->in(0)) {
|
|
n = n->in(0)->in(0)->in(0);
|
|
}
|
|
inner_loop = inner_loop->_child;
|
|
inner_head = inner_loop->_head->as_Loop();
|
|
inner_head->verify_strip_mined(1);
|
|
}
|
|
float loop_exit_cnt = 0.0f;
|
|
for (uint i = 0; i < inner_loop->_body.size(); i++) {
|
|
Node *n = inner_loop->_body[i];
|
|
float c = inner_loop->compute_profile_trip_cnt_helper(n);
|
|
loop_exit_cnt += c;
|
|
}
|
|
float cnt = -1;
|
|
if (n->in(0)->is_If()) {
|
|
IfNode* iff = n->in(0)->as_If();
|
|
float p = n->in(0)->as_If()->_prob;
|
|
if (n->Opcode() == Op_IfFalse) {
|
|
p = 1 - p;
|
|
}
|
|
if (p > PROB_MIN) {
|
|
cnt = p * iff->_fcnt;
|
|
} else {
|
|
cnt = 0;
|
|
}
|
|
} else {
|
|
assert(n->in(0)->is_Jump(), "unsupported node kind");
|
|
JumpNode* jmp = n->in(0)->as_Jump();
|
|
float p = n->in(0)->as_Jump()->_probs[n->as_JumpProj()->_con];
|
|
cnt = p * jmp->_fcnt;
|
|
}
|
|
float this_exit_f = cnt > 0 ? cnt / loop_exit_cnt : 0;
|
|
this_exit_f = check_and_truncate_frequency(this_exit_f);
|
|
f = f * this_exit_f;
|
|
f = check_and_truncate_frequency(f);
|
|
} else {
|
|
float p = -1;
|
|
if (n->in(0)->is_If()) {
|
|
p = n->in(0)->as_If()->_prob;
|
|
if (n->Opcode() == Op_IfFalse) {
|
|
p = 1 - p;
|
|
}
|
|
} else {
|
|
assert(n->in(0)->is_Jump(), "unsupported node kind");
|
|
p = n->in(0)->as_Jump()->_probs[n->as_JumpProj()->_con];
|
|
}
|
|
f = f * p;
|
|
f = check_and_truncate_frequency(f);
|
|
}
|
|
_freqs.at_put_grow(n->_idx, (float)f, -1);
|
|
_stack.pop();
|
|
} else {
|
|
float prev_f = _freqs_stack.pop();
|
|
float new_f = f;
|
|
f = new_f + prev_f;
|
|
f = check_and_truncate_frequency(f);
|
|
uint i = _stack.index();
|
|
if (i < n->req()) {
|
|
c = n->in(i);
|
|
_stack.set_index(i+1);
|
|
_freqs_stack.push(f);
|
|
} else {
|
|
_freqs.at_put_grow(n->_idx, f, -1);
|
|
_stack.pop();
|
|
}
|
|
}
|
|
}
|
|
if (_stack.size() == 0) {
|
|
return check_and_truncate_frequency(f);
|
|
}
|
|
} else if (c->is_Loop()) {
|
|
ShouldNotReachHere();
|
|
c = c->in(LoopNode::EntryControl);
|
|
} else if (c->is_Region()) {
|
|
_freqs_stack.push(0);
|
|
_stack.push(c, 2);
|
|
c = c->in(1);
|
|
} else {
|
|
if (c->is_IfProj()) {
|
|
IfNode* iff = c->in(0)->as_If();
|
|
if (iff->_prob == PROB_UNKNOWN) {
|
|
// assume never taken
|
|
_freqs.at_put_grow(c->_idx, 0, -1);
|
|
} else if (_phase->get_loop(c) != _phase->get_loop(iff)) {
|
|
if (iff->_fcnt == COUNT_UNKNOWN) {
|
|
// assume never taken
|
|
_freqs.at_put_grow(c->_idx, 0, -1);
|
|
} else {
|
|
// skip over loop
|
|
_stack.push(c, 1);
|
|
c = _phase->get_loop(c->in(0))->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
|
|
}
|
|
} else {
|
|
_stack.push(c, 1);
|
|
c = iff;
|
|
}
|
|
} else if (c->is_JumpProj()) {
|
|
JumpNode* jmp = c->in(0)->as_Jump();
|
|
if (_phase->get_loop(c) != _phase->get_loop(jmp)) {
|
|
if (jmp->_fcnt == COUNT_UNKNOWN) {
|
|
// assume never taken
|
|
_freqs.at_put_grow(c->_idx, 0, -1);
|
|
} else {
|
|
// skip over loop
|
|
_stack.push(c, 1);
|
|
c = _phase->get_loop(c->in(0))->_head->as_Loop()->skip_strip_mined()->in(LoopNode::EntryControl);
|
|
}
|
|
} else {
|
|
_stack.push(c, 1);
|
|
c = jmp;
|
|
}
|
|
} else if (c->Opcode() == Op_CatchProj &&
|
|
c->in(0)->Opcode() == Op_Catch &&
|
|
c->in(0)->in(0)->is_Proj() &&
|
|
c->in(0)->in(0)->in(0)->is_Call()) {
|
|
// assume exceptions are never thrown
|
|
uint con = c->as_Proj()->_con;
|
|
if (con == CatchProjNode::fall_through_index) {
|
|
Node* call = c->in(0)->in(0)->in(0)->in(0);
|
|
if (_phase->get_loop(call) != _phase->get_loop(c)) {
|
|
_freqs.at_put_grow(c->_idx, 0, -1);
|
|
} else {
|
|
c = call;
|
|
}
|
|
} else {
|
|
assert(con >= CatchProjNode::catch_all_index, "what else?");
|
|
_freqs.at_put_grow(c->_idx, 0, -1);
|
|
}
|
|
} else if (c->unique_ctrl_out_or_null() == nullptr && !c->is_If() && !c->is_Jump()) {
|
|
ShouldNotReachHere();
|
|
} else {
|
|
c = c->in(0);
|
|
}
|
|
}
|
|
}
|
|
ShouldNotReachHere();
|
|
return -1;
|
|
}
|
|
|
|
void PhaseIdealLoop::loop_predication_follow_branches(Node *n, IdealLoopTree *loop, float loop_trip_cnt,
|
|
PathFrequency& pf, Node_Stack& stack, VectorSet& seen,
|
|
Node_List& if_proj_list) {
|
|
assert(n->is_Region(), "start from a region");
|
|
Node* tail = loop->tail();
|
|
stack.push(n, 1);
|
|
do {
|
|
Node* c = stack.node();
|
|
assert(c->is_Region() || c->is_IfProj(), "only region here");
|
|
uint i = stack.index();
|
|
|
|
if (i < c->req()) {
|
|
stack.set_index(i+1);
|
|
Node* in = c->in(i);
|
|
while (!is_dominator(in, tail) && !seen.test_set(in->_idx)) {
|
|
IdealLoopTree* in_loop = get_loop(in);
|
|
if (in_loop != loop) {
|
|
in = in_loop->_head->in(LoopNode::EntryControl);
|
|
} else if (in->is_Region()) {
|
|
stack.push(in, 1);
|
|
break;
|
|
} else if (in->is_IfProj() &&
|
|
in->as_Proj()->is_uncommon_trap_if_pattern() &&
|
|
(in->in(0)->Opcode() == Op_If ||
|
|
in->in(0)->Opcode() == Op_RangeCheck)) {
|
|
if (pf.to(in) * loop_trip_cnt >= 1) {
|
|
stack.push(in, 1);
|
|
}
|
|
in = in->in(0);
|
|
} else {
|
|
in = in->in(0);
|
|
}
|
|
}
|
|
} else {
|
|
if (c->is_IfProj()) {
|
|
if_proj_list.push(c);
|
|
}
|
|
stack.pop();
|
|
}
|
|
|
|
} while (stack.size() > 0);
|
|
}
|
|
|
|
bool PhaseIdealLoop::loop_predication_impl_helper(IdealLoopTree* loop, IfProjNode* if_success_proj,
|
|
ParsePredicateSuccessProj* parse_predicate_proj, CountedLoopNode* cl,
|
|
ConNode* zero, Invariance& invar, Deoptimization::DeoptReason reason) {
|
|
// Following are changed to nonnull when a predicate can be hoisted
|
|
IfProjNode* new_predicate_proj = nullptr;
|
|
IfNode* iff = if_success_proj->in(0)->as_If();
|
|
Node* test = iff->in(1);
|
|
if (!test->is_Bool()) { //Conv2B, ...
|
|
return false;
|
|
}
|
|
BoolNode* bol = test->as_Bool();
|
|
if (invar.is_invariant(bol)) {
|
|
C->print_method(PHASE_BEFORE_LOOP_PREDICATION_IC, 4, iff);
|
|
// Invariant test
|
|
new_predicate_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr,
|
|
reason,
|
|
iff->Opcode());
|
|
Node* ctrl = new_predicate_proj->in(0)->as_If()->in(0);
|
|
BoolNode* new_predicate_bol = invar.clone(bol, ctrl)->as_Bool();
|
|
|
|
// Negate test if necessary (Parse Predicates always have IfTrue as success projection and IfFalse as uncommon trap)
|
|
bool negated = false;
|
|
if (if_success_proj->is_IfFalse()) {
|
|
new_predicate_bol = new BoolNode(new_predicate_bol->in(1), new_predicate_bol->_test.negate());
|
|
register_new_node(new_predicate_bol, ctrl);
|
|
negated = true;
|
|
}
|
|
IfNode* new_predicate_iff = new_predicate_proj->in(0)->as_If();
|
|
_igvn.hash_delete(new_predicate_iff);
|
|
new_predicate_iff->set_req(1, new_predicate_bol);
|
|
|
|
C->print_method(PHASE_AFTER_LOOP_PREDICATION_IC, 4, new_predicate_proj->in(0));
|
|
|
|
#ifndef PRODUCT
|
|
if (TraceLoopPredicate) {
|
|
tty->print("Predicate invariant if%s: %d ", negated ? " negated" : "", new_predicate_iff->_idx);
|
|
loop->dump_head();
|
|
} else if (TraceLoopOpts) {
|
|
tty->print("Predicate IC ");
|
|
loop->dump_head();
|
|
}
|
|
#endif
|
|
} else if (cl != nullptr && loop->is_range_check_if(if_success_proj, this, invar DEBUG_ONLY(COMMA parse_predicate_proj))) {
|
|
C->print_method(PHASE_BEFORE_LOOP_PREDICATION_RC, 4, iff);
|
|
// Range check for counted loops
|
|
assert(if_success_proj->is_IfTrue(), "trap must be on false projection for a range check");
|
|
const Node* cmp = bol->in(1)->as_Cmp();
|
|
Node* idx = cmp->in(1);
|
|
assert(!invar.is_invariant(idx), "index is variant");
|
|
Node* rng = cmp->in(2);
|
|
assert(rng->Opcode() == Op_LoadRange || iff->is_RangeCheck() || _igvn.type(rng)->is_int()->_lo >= 0, "must be");
|
|
assert(invar.is_invariant(rng), "range must be invariant");
|
|
int scale = 1;
|
|
Node* offset = zero;
|
|
bool ok = is_scaled_iv_plus_offset(idx, cl->phi(), &scale, &offset);
|
|
assert(ok, "must be index expression");
|
|
|
|
Node* init = cl->init_trip();
|
|
// Limit is not exact.
|
|
// Calculate exact limit here.
|
|
// Note, counted loop's test is '<' or '>'.
|
|
loop->compute_trip_count(this);
|
|
Node* limit = exact_limit(loop);
|
|
int stride = cl->stride()->get_int();
|
|
|
|
// Build if's for the upper and lower bound tests. The
|
|
// lower_bound test will dominate the upper bound test and all
|
|
// cloned or created nodes will use the lower bound test as
|
|
// their declared control.
|
|
|
|
// Perform cloning to keep Invariance state correct since the
|
|
// late schedule will place invariant things in the loop.
|
|
Node* ctrl = parse_predicate_proj->in(0)->as_If()->in(0);
|
|
rng = invar.clone(rng, ctrl);
|
|
if (offset && offset != zero) {
|
|
assert(invar.is_invariant(offset), "offset must be loop invariant");
|
|
offset = invar.clone(offset, ctrl);
|
|
}
|
|
// If predicate expressions may overflow in the integer range, longs are used.
|
|
bool overflow = false;
|
|
// Test the lower bound
|
|
BoolNode* lower_bound_bol = rc_predicate(loop, ctrl, scale, offset, init, limit, stride, rng, false, overflow);
|
|
|
|
const int if_opcode = iff->Opcode();
|
|
IfProjNode* lower_bound_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr, reason, overflow ? Op_If : if_opcode);
|
|
IfNode* lower_bound_iff = lower_bound_proj->in(0)->as_If();
|
|
_igvn.hash_delete(lower_bound_iff);
|
|
lower_bound_iff->set_req(1, lower_bound_bol);
|
|
if (TraceLoopPredicate) tty->print_cr("lower bound check if: %d", lower_bound_iff->_idx);
|
|
|
|
// Test the upper bound
|
|
BoolNode* upper_bound_bol = rc_predicate(loop, lower_bound_proj, scale, offset, init, limit, stride, rng, true,
|
|
overflow);
|
|
|
|
IfProjNode* upper_bound_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr, reason, overflow ? Op_If : if_opcode);
|
|
assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate");
|
|
IfNode* upper_bound_iff = upper_bound_proj->in(0)->as_If();
|
|
_igvn.hash_delete(upper_bound_iff);
|
|
upper_bound_iff->set_req(1, upper_bound_bol);
|
|
if (TraceLoopPredicate) tty->print_cr("upper bound check if: %d", lower_bound_iff->_idx);
|
|
|
|
// Fall through into rest of the cleanup code which will move any dependent nodes to the skeleton predicates of the
|
|
// upper bound test. We always need to create skeleton predicates in order to properly remove dead loops when later
|
|
// splitting the predicated loop into (unreachable) sub-loops (i.e. done by unrolling, peeling, pre/main/post etc.).
|
|
new_predicate_proj = add_template_assertion_predicate(iff, loop, if_success_proj, parse_predicate_proj, upper_bound_proj, scale,
|
|
offset, init, limit, stride, rng, overflow, reason);
|
|
|
|
C->print_method(PHASE_AFTER_LOOP_PREDICATION_RC, 4, new_predicate_proj->in(0));
|
|
|
|
#ifndef PRODUCT
|
|
if (TraceLoopOpts && !TraceLoopPredicate) {
|
|
tty->print("Predicate RC ");
|
|
loop->dump_head();
|
|
}
|
|
#endif
|
|
} else {
|
|
// Loop variant check (for example, range check in non-counted loop)
|
|
// with uncommon trap.
|
|
return false;
|
|
}
|
|
assert(new_predicate_proj != nullptr, "sanity");
|
|
// Success - attach condition (new_predicate_bol) to predicate if
|
|
invar.map_ctrl(if_success_proj, new_predicate_proj); // so that invariance test can be appropriate
|
|
|
|
// Eliminate the old If in the loop body
|
|
dominated_by(new_predicate_proj, iff, if_success_proj->_con != new_predicate_proj->_con);
|
|
|
|
C->set_major_progress();
|
|
return true;
|
|
}
|
|
|
|
// Each newly created Hoisted Check Predicate is accompanied by two Template Assertion Predicates. Later, we initialize
|
|
// them by making a copy of them when splitting a loop into sub loops. The Assertion Predicates ensure that dead sub
|
|
// loops are removed properly.
|
|
IfProjNode* PhaseIdealLoop::add_template_assertion_predicate(IfNode* iff, IdealLoopTree* loop, IfProjNode* if_proj,
|
|
ParsePredicateSuccessProj* parse_predicate_proj,
|
|
IfProjNode* upper_bound_proj, const int scale, Node* offset,
|
|
Node* init, Node* limit, const jint stride,
|
|
Node* rng, bool& overflow, Deoptimization::DeoptReason reason) {
|
|
// First predicate for the initial value on first loop iteration
|
|
Node* opaque_init = new OpaqueLoopInitNode(C, init);
|
|
register_new_node(opaque_init, upper_bound_proj);
|
|
bool negate = (if_proj->_con != parse_predicate_proj->_con);
|
|
BoolNode* bol = rc_predicate(loop, upper_bound_proj, scale, offset, opaque_init, limit, stride, rng,
|
|
(stride > 0) != (scale > 0), overflow);
|
|
Node* opaque_bol = new Opaque4Node(C, bol, _igvn.intcon(1)); // This will go away once loop opts are over
|
|
C->add_template_assertion_predicate_opaq(opaque_bol);
|
|
register_new_node(opaque_bol, upper_bound_proj);
|
|
IfProjNode* new_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr, reason, overflow ? Op_If : iff->Opcode());
|
|
_igvn.replace_input_of(new_proj->in(0), 1, opaque_bol);
|
|
assert(opaque_init->outcnt() > 0, "should be used");
|
|
|
|
// Second predicate for init + (current stride - initial stride)
|
|
// This is identical to the previous predicate initially but as
|
|
// unrolling proceeds current stride is updated.
|
|
Node* init_stride = loop->_head->as_CountedLoop()->stride();
|
|
Node* opaque_stride = new OpaqueLoopStrideNode(C, init_stride);
|
|
register_new_node(opaque_stride, new_proj);
|
|
Node* max_value = new SubINode(opaque_stride, init_stride);
|
|
register_new_node(max_value, new_proj);
|
|
max_value = new AddINode(opaque_init, max_value);
|
|
register_new_node(max_value, new_proj);
|
|
// init + (current stride - initial stride) is within the loop so narrow its type by leveraging the type of the iv Phi
|
|
max_value = new CastIINode(max_value, loop->_head->as_CountedLoop()->phi()->bottom_type());
|
|
register_new_node(max_value, parse_predicate_proj);
|
|
|
|
bol = rc_predicate(loop, new_proj, scale, offset, max_value, limit, stride, rng, (stride > 0) != (scale > 0),
|
|
overflow);
|
|
opaque_bol = new Opaque4Node(C, bol, _igvn.intcon(1));
|
|
C->add_template_assertion_predicate_opaq(opaque_bol);
|
|
register_new_node(opaque_bol, new_proj);
|
|
new_proj = create_new_if_for_predicate(parse_predicate_proj, nullptr, reason, overflow ? Op_If : iff->Opcode());
|
|
_igvn.replace_input_of(new_proj->in(0), 1, opaque_bol);
|
|
assert(max_value->outcnt() > 0, "should be used");
|
|
assert(assertion_predicate_has_loop_opaque_node(new_proj->in(0)->as_If()), "unexpected");
|
|
|
|
return new_proj;
|
|
}
|
|
|
|
// Insert Hoisted Check Predicates for null checks and range checks and additional Template Assertion Predicates for
|
|
// range checks.
|
|
bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree* loop) {
|
|
LoopNode* head = loop->_head->as_Loop();
|
|
|
|
if (head->unique_ctrl_out()->is_NeverBranch()) {
|
|
// do nothing for infinite loops
|
|
return false;
|
|
}
|
|
|
|
if (head->is_OuterStripMinedLoop()) {
|
|
return false;
|
|
}
|
|
|
|
CountedLoopNode *cl = nullptr;
|
|
if (head->is_valid_counted_loop(T_INT)) {
|
|
cl = head->as_CountedLoop();
|
|
// do nothing for iteration-splitted loops
|
|
if (!cl->is_normal_loop()) return false;
|
|
// Avoid RCE if Counted loop's test is '!='.
|
|
BoolTest::mask bt = cl->loopexit()->test_trip();
|
|
if (bt != BoolTest::lt && bt != BoolTest::gt)
|
|
cl = nullptr;
|
|
}
|
|
|
|
Node* entry = head->skip_strip_mined()->in(LoopNode::EntryControl);
|
|
const Predicates predicates(entry);
|
|
const PredicateBlock* loop_predicate_block = predicates.loop_predicate_block();
|
|
const PredicateBlock* profiled_loop_predicate_block = predicates.profiled_loop_predicate_block();
|
|
float loop_trip_cnt = -1;
|
|
bool follow_branches = profiled_loop_predicate_block->has_parse_predicate() &&
|
|
loop_predication_should_follow_branches(loop, loop_trip_cnt);
|
|
assert(!follow_branches || loop_trip_cnt >= 0, "negative trip count?");
|
|
|
|
if (!loop_predicate_block->has_parse_predicate() && !follow_branches) {
|
|
#ifndef PRODUCT
|
|
if (TraceLoopPredicate) {
|
|
tty->print("Missing Parse Predicates:");
|
|
loop->dump_head();
|
|
head->dump(1);
|
|
}
|
|
#endif
|
|
return false;
|
|
}
|
|
ConNode* zero = _igvn.intcon(0);
|
|
set_ctrl(zero, C->root());
|
|
|
|
ResourceArea* area = Thread::current()->resource_area();
|
|
Invariance invar(area, loop);
|
|
|
|
// Create list of if-projs such that a newer proj dominates all older
|
|
// projs in the list, and they all dominate loop->tail()
|
|
Node_List if_proj_list;
|
|
Node_List regions;
|
|
Node* current_proj = loop->tail(); // start from tail
|
|
|
|
|
|
Node_List controls;
|
|
while (current_proj != head) {
|
|
if (loop == get_loop(current_proj) && // still in the loop ?
|
|
current_proj->is_Proj() && // is a projection ?
|
|
(current_proj->in(0)->Opcode() == Op_If ||
|
|
current_proj->in(0)->Opcode() == Op_RangeCheck)) { // is a if projection ?
|
|
if_proj_list.push(current_proj);
|
|
}
|
|
if (follow_branches &&
|
|
current_proj->Opcode() == Op_Region &&
|
|
loop == get_loop(current_proj)) {
|
|
regions.push(current_proj);
|
|
}
|
|
current_proj = idom(current_proj);
|
|
}
|
|
|
|
bool hoisted = false; // true if at least one proj is promoted
|
|
|
|
if (can_create_loop_predicates(profiled_loop_predicate_block)) {
|
|
while (if_proj_list.size() > 0) {
|
|
Node* n = if_proj_list.pop();
|
|
|
|
IfProjNode* if_proj = n->as_IfProj();
|
|
IfNode* iff = if_proj->in(0)->as_If();
|
|
|
|
CallStaticJavaNode* call = if_proj->is_uncommon_trap_if_pattern();
|
|
if (call == nullptr) {
|
|
if (loop->is_loop_exit(iff)) {
|
|
// stop processing the remaining projs in the list because the execution of them
|
|
// depends on the condition of "iff" (iff->in(1)).
|
|
break;
|
|
} else {
|
|
// Both arms are inside the loop. There are two cases:
|
|
// (1) there is one backward branch. In this case, any remaining proj
|
|
// in the if_proj list post-dominates "iff". So, the condition of "iff"
|
|
// does not determine the execution the remaining projs directly, and we
|
|
// can safely continue.
|
|
// (2) both arms are forwarded, i.e. a diamond shape. In this case, "proj"
|
|
// does not dominate loop->tail(), so it can not be in the if_proj list.
|
|
continue;
|
|
}
|
|
}
|
|
Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(call->uncommon_trap_request());
|
|
if (reason == Deoptimization::Reason_predicate) {
|
|
break;
|
|
}
|
|
|
|
if (loop_predicate_block->has_parse_predicate()) {
|
|
ParsePredicateSuccessProj* loop_parse_predicate_proj = loop_predicate_block->parse_predicate_success_proj();
|
|
hoisted = loop_predication_impl_helper(loop, if_proj, loop_parse_predicate_proj, cl, zero, invar,
|
|
Deoptimization::Reason_predicate) | hoisted;
|
|
}
|
|
} // end while
|
|
}
|
|
|
|
if (follow_branches) {
|
|
assert(profiled_loop_predicate_block->has_parse_predicate(), "sanity check");
|
|
PathFrequency pf(loop->_head, this);
|
|
|
|
// Some projections were skipped due to an early loop exit. Try them with profile data.
|
|
while (if_proj_list.size() > 0) {
|
|
Node* if_proj = if_proj_list.pop();
|
|
float f = pf.to(if_proj);
|
|
if (if_proj->as_Proj()->is_uncommon_trap_if_pattern() &&
|
|
f * loop_trip_cnt >= 1) {
|
|
ParsePredicateSuccessProj* profiled_loop_parse_predicate_proj =
|
|
profiled_loop_predicate_block->parse_predicate_success_proj();
|
|
hoisted = loop_predication_impl_helper(loop, if_proj->as_IfProj(), profiled_loop_parse_predicate_proj,
|
|
cl, zero, invar, Deoptimization::Reason_profile_predicate) | hoisted;
|
|
}
|
|
}
|
|
|
|
// And look into all branches
|
|
Node_Stack stack(0);
|
|
VectorSet seen;
|
|
Node_List if_proj_list_freq(area);
|
|
while (regions.size() > 0) {
|
|
Node* c = regions.pop();
|
|
loop_predication_follow_branches(c, loop, loop_trip_cnt, pf, stack, seen, if_proj_list_freq);
|
|
}
|
|
|
|
for (uint i = 0; i < if_proj_list_freq.size(); i++) {
|
|
IfProjNode* if_proj = if_proj_list_freq.at(i)->as_IfProj();
|
|
ParsePredicateSuccessProj* profiled_loop_parse_predicate_proj =
|
|
profiled_loop_predicate_block->parse_predicate_success_proj();
|
|
hoisted = loop_predication_impl_helper(loop, if_proj, profiled_loop_parse_predicate_proj, cl, zero,
|
|
invar, Deoptimization::Reason_profile_predicate) | hoisted;
|
|
}
|
|
}
|
|
|
|
#ifndef PRODUCT
|
|
// report that the loop predication has been actually performed
|
|
// for this loop
|
|
if (TraceLoopPredicate && hoisted) {
|
|
tty->print("Loop Predication Performed:");
|
|
loop->dump_head();
|
|
}
|
|
#endif
|
|
|
|
head->verify_strip_mined(1);
|
|
|
|
return hoisted;
|
|
}
|
|
|
|
// We cannot add Loop Predicates if:
|
|
// (1) Already added Profiled Loop Predicates (Loop Predicates and Profiled Loop Predicates can be dependent
|
|
// through a data node, and thus we should only add new Profiled Loop Predicates which are below Loop Predicates
|
|
// in the graph).
|
|
// (2) There are currently no Profiled Loop Predicates, but we have a data node with a control dependency on the Loop
|
|
// Parse Predicate (could happen, for example, if we've removed an earlier created Profiled Loop Predicate with
|
|
// dominated_by()). We should not create a Loop Predicate for a check that is dependent on this data node because
|
|
// the Loop Predicate would end up above the data node with its dependency on the Loop Parse Predicate below. This
|
|
// would become unschedulable. However, we can still hoist the check as Profiled Loop Predicate which would end up
|
|
// below the Loop Parse Predicate.
|
|
bool PhaseIdealLoop::can_create_loop_predicates(const PredicateBlock* profiled_loop_predicate_block) const {
|
|
bool has_profiled_loop_predicate_block = profiled_loop_predicate_block != nullptr;
|
|
bool can_create_loop_predicates = true;
|
|
if (has_profiled_loop_predicate_block
|
|
&& (profiled_loop_predicate_block->has_runtime_predicates() // (1)
|
|
|| profiled_loop_predicate_block->entry()->outcnt() != 1)) { // (2)
|
|
can_create_loop_predicates = false;
|
|
}
|
|
return can_create_loop_predicates;
|
|
}
|
|
|
|
//------------------------------loop_predication--------------------------------
|
|
// driver routine for loop predication optimization
|
|
bool IdealLoopTree::loop_predication( PhaseIdealLoop *phase) {
|
|
bool hoisted = false;
|
|
// Recursively promote predicates
|
|
if (_child) {
|
|
hoisted = _child->loop_predication( phase);
|
|
}
|
|
|
|
// self
|
|
if (can_apply_loop_predication()) {
|
|
hoisted |= phase->loop_predication_impl(this);
|
|
}
|
|
|
|
if (_next) { //sibling
|
|
hoisted |= _next->loop_predication( phase);
|
|
}
|
|
|
|
return hoisted;
|
|
}
|
|
|
|
bool IdealLoopTree::can_apply_loop_predication() {
|
|
return _head->is_Loop() && !_irreducible && !tail()->is_top();
|
|
}
|