1 /* 2 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.loop; 24 25 import static org.graalvm.compiler.core.common.GraalOptions.LoopMaxUnswitch; 26 import static org.graalvm.compiler.core.common.GraalOptions.MaximumDesiredSize; 27 import static org.graalvm.compiler.core.common.GraalOptions.MinimumPeelProbability; 28 29 import java.util.List; 30 31 import org.graalvm.compiler.debug.Debug; 32 import org.graalvm.compiler.debug.DebugCounter; 33 import org.graalvm.compiler.graph.Node; 34 import org.graalvm.compiler.graph.NodeBitMap; 35 import org.graalvm.compiler.nodes.AbstractBeginNode; 36 import org.graalvm.compiler.nodes.ControlSplitNode; 37 import org.graalvm.compiler.nodes.DeoptimizeNode; 38 import org.graalvm.compiler.nodes.FixedNode; 39 import org.graalvm.compiler.nodes.FixedWithNextNode; 40 import org.graalvm.compiler.nodes.LoopBeginNode; 41 import org.graalvm.compiler.nodes.MergeNode; 42 import org.graalvm.compiler.nodes.VirtualState; 43 import org.graalvm.compiler.nodes.VirtualState.VirtualClosure; 44 import org.graalvm.compiler.nodes.cfg.Block; 45 import org.graalvm.compiler.nodes.cfg.ControlFlowGraph; 46 import org.graalvm.compiler.nodes.java.TypeSwitchNode; 47 import org.graalvm.compiler.options.Option; 48 import org.graalvm.compiler.options.OptionType; 49 import org.graalvm.compiler.options.OptionValues; 50 import org.graalvm.compiler.options.OptionKey; 51 52 import jdk.vm.ci.meta.MetaAccessProvider; 53 54 public class DefaultLoopPolicies implements LoopPolicies { 55 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Integer> LoopUnswitchMaxIncrease = new OptionKey<>(500); 56 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Integer> LoopUnswitchTrivial = new OptionKey<>(10); 57 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Double> LoopUnswitchFrequencyBoost = new OptionKey<>(10.0); 58 59 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Integer> FullUnrollMaxNodes = new OptionKey<>(300); 60 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Integer> FullUnrollMaxIterations = new OptionKey<>(600); 61 @Option(help = "", type = OptionType.Expert) public static final OptionKey<Integer> ExactFullUnrollMaxNodes = new OptionKey<>(1200); 62 63 @Override 64 public boolean shouldPeel(LoopEx loop, ControlFlowGraph cfg, MetaAccessProvider metaAccess) { 65 LoopBeginNode loopBegin = loop.loopBegin(); 66 double entryProbability = cfg.blockFor(loopBegin.forwardEnd()).probability(); 67 OptionValues options = cfg.graph.getOptions(); 68 if (entryProbability > MinimumPeelProbability.getValue(options) && loop.size() + loopBegin.graph().getNodeCount() < MaximumDesiredSize.getValue(options)) { 69 // check whether we're allowed to peel this loop 70 return loop.canDuplicateLoop(); 71 } else { 72 return false; 73 } 74 } 75 76 @Override 77 public boolean shouldFullUnroll(LoopEx loop) { 78 if (!loop.isCounted() || !loop.counted().isConstantMaxTripCount()) { 79 return false; 80 } 81 OptionValues options = loop.entryPoint().getOptions(); 82 CountedLoopInfo counted = loop.counted(); 83 long maxTrips = counted.constantMaxTripCount(); 84 int maxNodes = (counted.isExactTripCount() && counted.isConstantExactTripCount()) ? ExactFullUnrollMaxNodes.getValue(options) : FullUnrollMaxNodes.getValue(options); 85 maxNodes = Math.min(maxNodes, Math.max(0, MaximumDesiredSize.getValue(options) - loop.loopBegin().graph().getNodeCount())); 86 int size = Math.max(1, loop.size() - 1 - loop.loopBegin().phis().count()); 87 if (maxTrips <= FullUnrollMaxIterations.getValue(options) && size * (maxTrips - 1) <= maxNodes) { 88 // check whether we're allowed to unroll this loop 89 return loop.canDuplicateLoop(); 90 } else { 91 return false; 92 } 93 } 94 95 @Override 96 public boolean shouldTryUnswitch(LoopEx loop) { 97 LoopBeginNode loopBegin = loop.loopBegin(); 98 double loopFrequency = loopBegin.loopFrequency(); 99 if (loopFrequency <= 1.0) { 100 return false; 101 } 102 OptionValues options = loop.entryPoint().getOptions(); 103 return loopBegin.unswitches() <= LoopMaxUnswitch.getValue(options); 104 } 105 106 private static final class CountingClosure implements VirtualClosure { 107 int count; 108 109 @Override 110 public void apply(VirtualState node) { 111 count++; 112 } 113 } 114 115 private static class IsolatedInitialization { 116 static final DebugCounter UNSWITCH_SPLIT_WITH_PHIS = Debug.counter("UnswitchSplitWithPhis"); 117 } 118 119 @Override 120 public boolean shouldUnswitch(LoopEx loop, List<ControlSplitNode> controlSplits) { 121 int phis = 0; 122 NodeBitMap branchNodes = loop.loopBegin().graph().createNodeBitMap(); 123 for (ControlSplitNode controlSplit : controlSplits) { 124 for (Node successor : controlSplit.successors()) { 125 AbstractBeginNode branch = (AbstractBeginNode) successor; 126 // this may count twice because of fall-through in switches 127 loop.nodesInLoopBranch(branchNodes, branch); 128 } 129 Block postDomBlock = loop.loopsData().getCFG().blockFor(controlSplit).getPostdominator(); 130 if (postDomBlock != null) { 131 IsolatedInitialization.UNSWITCH_SPLIT_WITH_PHIS.increment(); 132 phis += ((MergeNode) postDomBlock.getBeginNode()).phis().count(); 133 } 134 } 135 int inBranchTotal = branchNodes.count(); 136 137 CountingClosure stateNodesCount = new CountingClosure(); 138 double loopFrequency = loop.loopBegin().loopFrequency(); 139 OptionValues options = loop.loopBegin().getOptions(); 140 int maxDiff = LoopUnswitchTrivial.getValue(options) + (int) (LoopUnswitchFrequencyBoost.getValue(options) * (loopFrequency - 1.0 + phis)); 141 142 maxDiff = Math.min(maxDiff, LoopUnswitchMaxIncrease.getValue(options)); 143 int remainingGraphSpace = MaximumDesiredSize.getValue(options) - loop.loopBegin().graph().getNodeCount(); 144 maxDiff = Math.min(maxDiff, remainingGraphSpace); 145 146 loop.loopBegin().stateAfter().applyToVirtual(stateNodesCount); 147 int loopTotal = loop.size() - loop.loopBegin().phis().count() - stateNodesCount.count - 1; 148 int actualDiff = (loopTotal - inBranchTotal); 149 ControlSplitNode firstSplit = controlSplits.get(0); 150 if (firstSplit instanceof TypeSwitchNode) { 151 int copies = firstSplit.successors().count() - 1; 152 for (Node succ : firstSplit.successors()) { 153 FixedNode current = (FixedNode) succ; 154 while (current instanceof FixedWithNextNode) { 155 current = ((FixedWithNextNode) current).next(); 156 } 157 if (current instanceof DeoptimizeNode) { 158 copies--; 159 } 160 } 161 actualDiff = actualDiff * copies; 162 } 163 164 Debug.log("shouldUnswitch(%s, %s) : delta=%d (%.2f%% inside of branches), max=%d, f=%.2f, phis=%d -> %b", loop, controlSplits, actualDiff, (double) (inBranchTotal) / loopTotal * 100, maxDiff, 165 loopFrequency, phis, actualDiff <= maxDiff); 166 if (actualDiff <= maxDiff) { 167 // check whether we're allowed to unswitch this loop 168 return loop.canDuplicateLoop(); 169 } else { 170 return false; 171 } 172 } 173 174 }