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7004535: Clone loop predicate during loop unswitch
Clone loop predicate for clonned loops Reviewed-by: never
This commit is contained in:
Vladimir Kozlov
parent
68f1177f59
commit
00eca5e982
14 changed files with 1298 additions and 716 deletions
960
hotspot/src/share/vm/opto/loopPredicate.cpp
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960
hotspot/src/share/vm/opto/loopPredicate.cpp
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/*
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* Copyright (c) 2011, 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 "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/connode.hpp"
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#include "opto/loopnode.hpp"
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#include "opto/mulnode.hpp"
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#include "opto/rootnode.hpp"
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#include "opto/subnode.hpp"
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/*
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* The general idea of Loop Predication is to insert a predicate on the entry
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* path to a loop, and raise a uncommon trap if the check of the condition fails.
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* The condition checks are promoted from inside the loop body, and thus
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* the checks inside the loop could be eliminated. Currently, loop predication
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* optimization has been applied to remove array range check and loop invariant
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* checks (such as null checks).
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*/
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//-------------------------------is_uncommon_trap_proj----------------------------
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// Return true if proj is the form of "proj->[region->..]call_uct"
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bool PhaseIdealLoop::is_uncommon_trap_proj(ProjNode* proj, Deoptimization::DeoptReason reason) {
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int path_limit = 10;
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assert(proj, "invalid argument");
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Node* out = proj;
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for (int ct = 0; ct < path_limit; ct++) {
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out = out->unique_ctrl_out();
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if (out == NULL)
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return false;
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if (out->is_CallStaticJava()) {
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int req = out->as_CallStaticJava()->uncommon_trap_request();
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if (req != 0) {
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Deoptimization::DeoptReason trap_reason = Deoptimization::trap_request_reason(req);
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if (trap_reason == reason || reason == Deoptimization::Reason_none) {
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return true;
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}
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}
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return false; // don't do further after call
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}
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if (out->Opcode() != Op_Region)
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return false;
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}
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return false;
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}
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//-------------------------------is_uncommon_trap_if_pattern-------------------------
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// Return true for "if(test)-> proj -> ...
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// |
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// V
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// other_proj->[region->..]call_uct"
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//
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// "must_reason_predicate" means the uct reason must be Reason_predicate
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bool PhaseIdealLoop::is_uncommon_trap_if_pattern(ProjNode *proj, Deoptimization::DeoptReason reason) {
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Node *in0 = proj->in(0);
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if (!in0->is_If()) return false;
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// Variation of a dead If node.
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if (in0->outcnt() < 2) return false;
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IfNode* iff = in0->as_If();
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// we need "If(Conv2B(Opaque1(...)))" pattern for reason_predicate
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if (reason != Deoptimization::Reason_none) {
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if (iff->in(1)->Opcode() != Op_Conv2B ||
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iff->in(1)->in(1)->Opcode() != Op_Opaque1) {
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return false;
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}
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}
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ProjNode* other_proj = iff->proj_out(1-proj->_con)->as_Proj();
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if (is_uncommon_trap_proj(other_proj, reason)) {
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assert(reason == Deoptimization::Reason_none ||
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Compile::current()->is_predicate_opaq(iff->in(1)->in(1)), "should be on the list");
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return true;
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}
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return false;
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}
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//-------------------------------register_control-------------------------
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void PhaseIdealLoop::register_control(Node* n, IdealLoopTree *loop, Node* pred) {
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assert(n->is_CFG(), "must be control node");
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_igvn.register_new_node_with_optimizer(n);
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loop->_body.push(n);
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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 != NULL) {
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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 true projecttion (if_cont) of the new_iff is returned.
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// This code is also used to clone predicates to clonned loops.
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ProjNode* PhaseIdealLoop::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry,
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Deoptimization::DeoptReason reason) {
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assert(is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!");
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IfNode* iff = cont_proj->in(0)->as_If();
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ProjNode *uncommon_proj = iff->proj_out(1 - cont_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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uint proj_index = 1; // region's edge corresponding to uncommon_proj
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if (!rgn->is_Region()) { // create a region to guard the call
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assert(rgn->is_Call(), "must be call uct");
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CallNode* call = rgn->as_Call();
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IdealLoopTree* loop = get_loop(call);
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rgn = new (C, 1) RegionNode(1);
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rgn->add_req(uncommon_proj);
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register_control(rgn, loop, uncommon_proj);
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_igvn.hash_delete(call);
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call->set_req(0, rgn);
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// When called from beautify_loops() idom is not constructed yet.
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if (_idom != NULL) {
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set_idom(call, rgn, dom_depth(rgn));
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}
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} else {
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// Find region's edge corresponding to uncommon_proj
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for (; proj_index < rgn->req(); proj_index++)
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if (rgn->in(proj_index) == uncommon_proj) break;
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assert(proj_index < rgn->req(), "sanity");
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}
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Node* entry = iff->in(0);
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if (new_entry != NULL) {
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// Clonning 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 = iff->clone()->as_If();
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new_iff->set_req(0, entry);
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register_control(new_iff, lp, entry);
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Node *if_cont = new (C, 1) IfTrueNode(new_iff);
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Node *if_uct = new (C, 1) IfFalseNode(new_iff);
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if (cont_proj->is_IfFalse()) {
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// Swap
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Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp;
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}
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register_control(if_cont, lp, new_iff);
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register_control(if_uct, get_loop(rgn), new_iff);
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// if_uct to rgn
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_igvn.hash_delete(rgn);
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rgn->add_req(if_uct);
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// When called from beautify_loops() idom is not constructed yet.
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if (_idom != NULL) {
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Node* ridom = idom(rgn);
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Node* nrdom = dom_lca(ridom, new_iff);
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set_idom(rgn, nrdom, dom_depth(rgn));
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}
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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(rgn->in(rgn->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 = rgn->fast_outs(imax); i < imax; i++) {
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Node* use = rgn->fast_out(i);
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if (use->is_Phi() && use->outcnt() > 0) {
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assert(use->in(0) == rgn, "");
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_igvn.hash_delete(use);
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use->add_req(use->in(proj_index));
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_igvn._worklist.push(use);
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has_phi = true;
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}
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}
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assert(!has_phi || rgn->req() > 3, "no phis when region is created");
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if (new_entry == NULL) {
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// Attach if_cont to iff
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_igvn.hash_delete(iff);
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iff->set_req(0, if_cont);
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if (_idom != NULL) {
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set_idom(iff, if_cont, dom_depth(iff));
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}
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}
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return if_cont->as_Proj();
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}
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//------------------------------create_new_if_for_predicate------------------------
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// Create a new if below new_entry for the predicate to be cloned (IGVN optimization)
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ProjNode* PhaseIterGVN::create_new_if_for_predicate(ProjNode* cont_proj, Node* new_entry,
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Deoptimization::DeoptReason reason) {
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assert(new_entry != 0, "only used for clone predicate");
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assert(PhaseIdealLoop::is_uncommon_trap_if_pattern(cont_proj, reason), "must be a uct if pattern!");
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IfNode* iff = cont_proj->in(0)->as_If();
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ProjNode *uncommon_proj = iff->proj_out(1 - cont_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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uint proj_index = 1; // region's edge corresponding to uncommon_proj
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if (!rgn->is_Region()) { // create a region to guard the call
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assert(rgn->is_Call(), "must be call uct");
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CallNode* call = rgn->as_Call();
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rgn = new (C, 1) RegionNode(1);
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register_new_node_with_optimizer(rgn);
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rgn->add_req(uncommon_proj);
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hash_delete(call);
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call->set_req(0, rgn);
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} else {
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// Find region's edge corresponding to uncommon_proj
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for (; proj_index < rgn->req(); proj_index++)
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if (rgn->in(proj_index) == uncommon_proj) break;
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assert(proj_index < rgn->req(), "sanity");
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}
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// Create new_iff in new location.
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IfNode *new_iff = iff->clone()->as_If();
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new_iff->set_req(0, new_entry);
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register_new_node_with_optimizer(new_iff);
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Node *if_cont = new (C, 1) IfTrueNode(new_iff);
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Node *if_uct = new (C, 1) IfFalseNode(new_iff);
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if (cont_proj->is_IfFalse()) {
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// Swap
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Node* tmp = if_uct; if_uct = if_cont; if_cont = tmp;
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}
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register_new_node_with_optimizer(if_cont);
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register_new_node_with_optimizer(if_uct);
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// if_uct to rgn
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hash_delete(rgn);
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rgn->add_req(if_uct);
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// If rgn has phis add corresponding new edges which has the same
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// value as on original uncommon_proj pass.
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assert(rgn->in(rgn->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 = rgn->fast_outs(imax); i < imax; i++) {
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Node* use = rgn->fast_out(i);
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if (use->is_Phi() && use->outcnt() > 0) {
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hash_delete(use);
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use->add_req(use->in(proj_index));
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_worklist.push(use);
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has_phi = true;
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}
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}
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assert(!has_phi || rgn->req() > 3, "no phis when region is created");
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return if_cont->as_Proj();
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}
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//--------------------------clone_predicate-----------------------
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ProjNode* PhaseIdealLoop::clone_predicate(ProjNode* predicate_proj, Node* new_entry,
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Deoptimization::DeoptReason reason,
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PhaseIdealLoop* loop_phase,
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PhaseIterGVN* igvn) {
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ProjNode* new_predicate_proj;
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if (loop_phase != NULL) {
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new_predicate_proj = loop_phase->create_new_if_for_predicate(predicate_proj, new_entry, reason);
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} else {
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new_predicate_proj = igvn->create_new_if_for_predicate(predicate_proj, new_entry, reason);
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}
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IfNode* iff = new_predicate_proj->in(0)->as_If();
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Node* ctrl = iff->in(0);
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// Match original condition since predicate's projections could be swapped.
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assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be");
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Node* opq = new (igvn->C, 2) Opaque1Node(igvn->C, predicate_proj->in(0)->in(1)->in(1)->in(1));
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igvn->C->add_predicate_opaq(opq);
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Node* bol = new (igvn->C, 2) Conv2BNode(opq);
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if (loop_phase != NULL) {
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loop_phase->register_new_node(opq, ctrl);
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loop_phase->register_new_node(bol, ctrl);
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} else {
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igvn->register_new_node_with_optimizer(opq);
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igvn->register_new_node_with_optimizer(bol);
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}
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igvn->hash_delete(iff);
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iff->set_req(1, bol);
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return new_predicate_proj;
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}
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//--------------------------move_predicate-----------------------
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// Cut predicate from old place and move it to new.
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ProjNode* PhaseIdealLoop::move_predicate(ProjNode* predicate_proj, Node* new_entry,
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Deoptimization::DeoptReason reason,
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PhaseIdealLoop* loop_phase,
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PhaseIterGVN* igvn) {
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assert(new_entry != NULL, "must be");
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assert(predicate_proj->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be");
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IfNode* iff = predicate_proj->in(0)->as_If();
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Node* old_entry = iff->in(0);
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// Cut predicate from old place.
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Node* old = predicate_proj;
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igvn->_worklist.push(old);
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for (DUIterator_Last imin, i = old->last_outs(imin); i >= imin; ) {
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Node* use = old->last_out(i); // for each use...
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igvn->hash_delete(use);
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igvn->_worklist.push(use);
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// Update use-def info
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uint uses_found = 0;
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for (uint j = 0; j < use->req(); j++) {
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if (use->in(j) == old) {
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use->set_req(j, old_entry);
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uses_found++;
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if (loop_phase != NULL) {
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if (use->is_CFG()) {
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// When called from beautify_loops() idom is not constructed yet.
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if (loop_phase->_idom != NULL)
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loop_phase->set_idom(use, old_entry, loop_phase->dom_depth(use));
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} else {
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loop_phase->set_ctrl(use, old_entry);
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}
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}
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}
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}
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i -= uses_found; // we deleted 1 or more copies of this edge
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}
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// Move predicate.
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igvn->hash_delete(iff);
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iff->set_req(0, new_entry);
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igvn->_worklist.push(iff);
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if (loop_phase != NULL) {
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// Fix up idom and ctrl.
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loop_phase->set_ctrl(iff->in(1), new_entry);
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loop_phase->set_ctrl(iff->in(1)->in(1), new_entry);
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// When called from beautify_loops() idom is not constructed yet.
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if (loop_phase->_idom != NULL)
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loop_phase->set_idom(iff, new_entry, loop_phase->dom_depth(iff));
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}
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return predicate_proj;
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}
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//--------------------------clone_loop_predicates-----------------------
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// Interface from IGVN
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Node* PhaseIterGVN::clone_loop_predicates(Node* old_entry, Node* new_entry) {
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return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, false, NULL, this);
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}
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Node* PhaseIterGVN::move_loop_predicates(Node* old_entry, Node* new_entry) {
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return PhaseIdealLoop::clone_loop_predicates(old_entry, new_entry, true, NULL, this);
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}
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// Interface from PhaseIdealLoop
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Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry) {
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return clone_loop_predicates(old_entry, new_entry, false, this, &this->_igvn);
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}
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Node* PhaseIdealLoop::move_loop_predicates(Node* old_entry, Node* new_entry) {
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return clone_loop_predicates(old_entry, new_entry, true, this, &this->_igvn);
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}
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// Clone loop predicates to cloned loops (peeled, unswitched, split_if).
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Node* PhaseIdealLoop::clone_loop_predicates(Node* old_entry, Node* new_entry,
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bool move_predicates,
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PhaseIdealLoop* loop_phase,
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PhaseIterGVN* igvn) {
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#ifdef ASSERT
|
||||
if (new_entry == NULL || !(new_entry->is_Proj() || new_entry->is_Region() || new_entry->is_SafePoint())) {
|
||||
if (new_entry != NULL)
|
||||
new_entry->dump();
|
||||
assert(false, "not IfTrue, IfFalse, Region or SafePoint");
|
||||
}
|
||||
#endif
|
||||
// Search original predicates
|
||||
Node* entry = old_entry;
|
||||
if (UseLoopPredicate) {
|
||||
ProjNode* predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
|
||||
if (predicate_proj != NULL) { // right pattern that can be used by loop predication
|
||||
assert(entry->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be");
|
||||
if (move_predicates) {
|
||||
new_entry = move_predicate(predicate_proj, new_entry,
|
||||
Deoptimization::Reason_predicate,
|
||||
loop_phase, igvn);
|
||||
assert(new_entry == predicate_proj, "old predicate fall through projection");
|
||||
} else {
|
||||
// clone predicate
|
||||
new_entry = clone_predicate(predicate_proj, new_entry,
|
||||
Deoptimization::Reason_predicate,
|
||||
loop_phase, igvn);
|
||||
assert(new_entry != NULL && new_entry->is_Proj(), "IfTrue or IfFalse after clone predicate");
|
||||
}
|
||||
if (TraceLoopPredicate) {
|
||||
tty->print_cr("Loop Predicate %s: ", move_predicates ? "moved" : "cloned");
|
||||
debug_only( new_entry->in(0)->dump(); )
|
||||
}
|
||||
}
|
||||
}
|
||||
return new_entry;
|
||||
}
|
||||
|
||||
//--------------------------eliminate_loop_predicates-----------------------
|
||||
void PhaseIdealLoop::eliminate_loop_predicates(Node* entry) {
|
||||
if (UseLoopPredicate) {
|
||||
ProjNode* predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
|
||||
if (predicate_proj != NULL) { // right pattern that can be used by loop predication
|
||||
Node* n = entry->in(0)->in(1)->in(1);
|
||||
assert(n->Opcode()==Op_Opaque1, "must be");
|
||||
// Remove Opaque1 node from predicates list.
|
||||
// IGVN will remove this predicate check.
|
||||
_igvn.replace_node(n, n->in(1));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//--------------------------skip_loop_predicates------------------------------
|
||||
// Skip related predicates.
|
||||
Node* PhaseIdealLoop::skip_loop_predicates(Node* entry) {
|
||||
Node* predicate = NULL;
|
||||
if (UseLoopPredicate) {
|
||||
predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
|
||||
if (predicate != NULL) { // right pattern that can be used by loop predication
|
||||
assert(entry->is_Proj() && entry->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be");
|
||||
IfNode* iff = entry->in(0)->as_If();
|
||||
ProjNode* uncommon_proj = iff->proj_out(1 - entry->as_Proj()->_con);
|
||||
Node* rgn = uncommon_proj->unique_ctrl_out();
|
||||
assert(rgn->is_Region() || rgn->is_Call(), "must be a region or call uct");
|
||||
entry = entry->in(0)->in(0);
|
||||
while (entry != NULL && entry->is_Proj() && entry->in(0)->is_If()) {
|
||||
uncommon_proj = entry->in(0)->as_If()->proj_out(1 - entry->as_Proj()->_con);
|
||||
if (uncommon_proj->unique_ctrl_out() != rgn)
|
||||
break;
|
||||
entry = entry->in(0)->in(0);
|
||||
}
|
||||
}
|
||||
}
|
||||
return entry;
|
||||
}
|
||||
|
||||
//--------------------------find_predicate_insertion_point-------------------
|
||||
// Find a good location to insert a predicate
|
||||
ProjNode* PhaseIdealLoop::find_predicate_insertion_point(Node* start_c, Deoptimization::DeoptReason reason) {
|
||||
if (start_c == NULL || !start_c->is_Proj())
|
||||
return NULL;
|
||||
if (is_uncommon_trap_if_pattern(start_c->as_Proj(), reason)) {
|
||||
return start_c->as_Proj();
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
//--------------------------find_predicate------------------------------------
|
||||
// Find a predicate
|
||||
Node* PhaseIdealLoop::find_predicate(Node* entry) {
|
||||
Node* predicate = NULL;
|
||||
if (UseLoopPredicate) {
|
||||
predicate = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
|
||||
if (predicate != NULL) { // right pattern that can be used by loop predication
|
||||
assert(entry->in(0)->in(1)->in(1)->Opcode()==Op_Opaque1, "must be");
|
||||
return entry;
|
||||
}
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
//------------------------------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;
|
||||
|
||||
// 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) == NULL ? 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 == NULL) 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) {
|
||||
_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 != NULL && !_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) == NULL ? 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 == NULL) 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 != NULL && !_clone_visited.test_set(m->_idx)) {
|
||||
clone_visit(m); // visit the input
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
public:
|
||||
Invariance(Arena* area, IdealLoopTree* lpt) :
|
||||
_lpt(lpt), _phase(lpt->_phase),
|
||||
_visited(area), _invariant(area), _stack(area, 10 /* guess */),
|
||||
_clone_visited(area), _old_new(area)
|
||||
{}
|
||||
|
||||
// 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(IfNode *iff, PhaseIdealLoop *phase, Invariance& invar) const {
|
||||
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) {
|
||||
return false;
|
||||
}
|
||||
if (!bol->in(1)->is_Cmp()) {
|
||||
return false;
|
||||
}
|
||||
const CmpNode *cmp = bol->in(1)->as_Cmp();
|
||||
if (cmp->Opcode() != Op_CmpU) {
|
||||
return false;
|
||||
}
|
||||
Node* range = cmp->in(2);
|
||||
if (range->Opcode() != Op_LoadRange) {
|
||||
const TypeInt* tint = phase->_igvn.type(range)->isa_int();
|
||||
if (!OptimizeFill || tint == NULL || tint->empty() || tint->_lo < 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;
|
||||
}
|
||||
}
|
||||
if (!invar.is_invariant(range)) {
|
||||
return false;
|
||||
}
|
||||
Node *iv = _head->as_CountedLoop()->phi();
|
||||
int scale = 0;
|
||||
Node *offset = NULL;
|
||||
if (!phase->is_scaled_iv_plus_offset(cmp->in(1), iv, &scale, &offset)) {
|
||||
return false;
|
||||
}
|
||||
if (offset && !invar.is_invariant(offset)) { // offset must be invariant
|
||||
return false;
|
||||
}
|
||||
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(Node* ctrl,
|
||||
int scale, Node* offset,
|
||||
Node* init, Node* limit, Node* stride,
|
||||
Node* range, bool upper) {
|
||||
DEBUG_ONLY(ttyLocker ttyl);
|
||||
if (TraceLoopPredicate) tty->print("rc_predicate ");
|
||||
|
||||
Node* max_idx_expr = init;
|
||||
int stride_con = stride->get_int();
|
||||
if ((stride_con > 0) == (scale > 0) == upper) {
|
||||
max_idx_expr = new (C, 3) SubINode(limit, stride);
|
||||
register_new_node(max_idx_expr, ctrl);
|
||||
if (TraceLoopPredicate) tty->print("(limit - stride) ");
|
||||
} else {
|
||||
if (TraceLoopPredicate) tty->print("init ");
|
||||
}
|
||||
|
||||
if (scale != 1) {
|
||||
ConNode* con_scale = _igvn.intcon(scale);
|
||||
max_idx_expr = new (C, 3) MulINode(max_idx_expr, con_scale);
|
||||
register_new_node(max_idx_expr, ctrl);
|
||||
if (TraceLoopPredicate) tty->print("* %d ", scale);
|
||||
}
|
||||
|
||||
if (offset && (!offset->is_Con() || offset->get_int() != 0)){
|
||||
max_idx_expr = new (C, 3) AddINode(max_idx_expr, offset);
|
||||
register_new_node(max_idx_expr, ctrl);
|
||||
if (TraceLoopPredicate)
|
||||
if (offset->is_Con()) tty->print("+ %d ", offset->get_int());
|
||||
else tty->print("+ offset ");
|
||||
}
|
||||
|
||||
CmpUNode* cmp = new (C, 3) CmpUNode(max_idx_expr, range);
|
||||
register_new_node(cmp, ctrl);
|
||||
BoolNode* bol = new (C, 2) BoolNode(cmp, BoolTest::lt);
|
||||
register_new_node(bol, ctrl);
|
||||
|
||||
if (TraceLoopPredicate) tty->print_cr("<u range");
|
||||
return bol;
|
||||
}
|
||||
|
||||
//------------------------------ loop_predication_impl--------------------------
|
||||
// Insert loop predicates for null checks and range checks
|
||||
bool PhaseIdealLoop::loop_predication_impl(IdealLoopTree *loop) {
|
||||
if (!UseLoopPredicate) return false;
|
||||
|
||||
if (!loop->_head->is_Loop()) {
|
||||
// Could be a simple region when irreducible loops are present.
|
||||
return false;
|
||||
}
|
||||
|
||||
if (loop->_head->unique_ctrl_out()->Opcode() == Op_NeverBranch) {
|
||||
// do nothing for infinite loops
|
||||
return false;
|
||||
}
|
||||
|
||||
CountedLoopNode *cl = NULL;
|
||||
if (loop->_head->is_CountedLoop()) {
|
||||
cl = loop->_head->as_CountedLoop();
|
||||
// do nothing for iteration-splitted loops
|
||||
if (!cl->is_normal_loop()) return false;
|
||||
}
|
||||
|
||||
LoopNode *lpn = loop->_head->as_Loop();
|
||||
Node* entry = lpn->in(LoopNode::EntryControl);
|
||||
|
||||
ProjNode *predicate_proj = find_predicate_insertion_point(entry, Deoptimization::Reason_predicate);
|
||||
if (!predicate_proj) {
|
||||
#ifndef PRODUCT
|
||||
if (TraceLoopPredicate) {
|
||||
tty->print("missing predicate:");
|
||||
loop->dump_head();
|
||||
lpn->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(area);
|
||||
LoopNode *head = loop->_head->as_Loop();
|
||||
Node *current_proj = loop->tail(); //start from tail
|
||||
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) { // is a if projection ?
|
||||
if_proj_list.push(current_proj);
|
||||
}
|
||||
current_proj = idom(current_proj);
|
||||
}
|
||||
|
||||
bool hoisted = false; // true if at least one proj is promoted
|
||||
while (if_proj_list.size() > 0) {
|
||||
// Following are changed to nonnull when a predicate can be hoisted
|
||||
ProjNode* new_predicate_proj = NULL;
|
||||
|
||||
ProjNode* proj = if_proj_list.pop()->as_Proj();
|
||||
IfNode* iff = proj->in(0)->as_If();
|
||||
|
||||
if (!is_uncommon_trap_if_pattern(proj, Deoptimization::Reason_none)) {
|
||||
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 remining 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;
|
||||
}
|
||||
}
|
||||
|
||||
Node* test = iff->in(1);
|
||||
if (!test->is_Bool()){ //Conv2B, ...
|
||||
continue;
|
||||
}
|
||||
BoolNode* bol = test->as_Bool();
|
||||
if (invar.is_invariant(bol)) {
|
||||
// Invariant test
|
||||
new_predicate_proj = create_new_if_for_predicate(predicate_proj, NULL,
|
||||
Deoptimization::Reason_predicate);
|
||||
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
|
||||
bool negated = false;
|
||||
if (proj->_con != predicate_proj->_con) {
|
||||
new_predicate_bol = new (C, 2) 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);
|
||||
#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 != NULL && loop->is_range_check_if(iff, this, invar)) {
|
||||
assert(proj->_con == predicate_proj->_con, "must match");
|
||||
|
||||
// Range check for counted loops
|
||||
const Node* cmp = bol->in(1)->as_Cmp();
|
||||
Node* idx = cmp->in(1);
|
||||
assert(!invar.is_invariant(idx), "index is variant");
|
||||
assert(cmp->in(2)->Opcode() == Op_LoadRange || OptimizeFill, "must be");
|
||||
Node* rng = cmp->in(2);
|
||||
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();
|
||||
Node* limit = cl->limit();
|
||||
Node* stride = cl->stride();
|
||||
|
||||
// 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.
|
||||
ProjNode* lower_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate);
|
||||
ProjNode* upper_bound_proj = create_new_if_for_predicate(predicate_proj, NULL, Deoptimization::Reason_predicate);
|
||||
assert(upper_bound_proj->in(0)->as_If()->in(0) == lower_bound_proj, "should dominate");
|
||||
Node *ctrl = lower_bound_proj->in(0)->as_If()->in(0);
|
||||
|
||||
// Perform cloning to keep Invariance state correct since the
|
||||
// late schedule will place invariant things in the loop.
|
||||
rng = invar.clone(rng, ctrl);
|
||||
if (offset && offset != zero) {
|
||||
assert(invar.is_invariant(offset), "offset must be loop invariant");
|
||||
offset = invar.clone(offset, ctrl);
|
||||
}
|
||||
|
||||
// Test the lower bound
|
||||
Node* lower_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, false);
|
||||
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
|
||||
Node* upper_bound_bol = rc_predicate(ctrl, scale, offset, init, limit, stride, rng, true);
|
||||
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 clean up code which will move
|
||||
// any dependent nodes onto the upper bound test.
|
||||
new_predicate_proj = upper_bound_proj;
|
||||
|
||||
#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.
|
||||
continue;
|
||||
}
|
||||
assert(new_predicate_proj != NULL, "sanity");
|
||||
// Success - attach condition (new_predicate_bol) to predicate if
|
||||
invar.map_ctrl(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, proj->_con != new_predicate_proj->_con );
|
||||
|
||||
hoisted = true;
|
||||
C->set_major_progress();
|
||||
} // end while
|
||||
|
||||
#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
|
||||
|
||||
return hoisted;
|
||||
}
|
||||
|
||||
//------------------------------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 (!_irreducible && !tail()->is_top()) {
|
||||
hoisted |= phase->loop_predication_impl(this);
|
||||
}
|
||||
|
||||
if (_next) { //sibling
|
||||
hoisted |= _next->loop_predication( phase);
|
||||
}
|
||||
|
||||
return hoisted;
|
||||
}
|
||||
|
||||
Loading…
Add table
Add a link
Reference in a new issue