1 /*
2 * Copyright (c) 2013, 2018, 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
24
25 package org.graalvm.compiler.phases.common;
26
27 import org.graalvm.compiler.core.common.type.Stamp;
28 import org.graalvm.compiler.debug.DebugCloseable;
29 import org.graalvm.compiler.debug.GraalError;
30 import org.graalvm.compiler.graph.Graph;
31 import org.graalvm.compiler.graph.Node;
32 import org.graalvm.compiler.nodes.AbstractBeginNode;
33 import org.graalvm.compiler.nodes.AbstractMergeNode;
34 import org.graalvm.compiler.nodes.BeginNode;
35 import org.graalvm.compiler.nodes.ConstantNode;
36 import org.graalvm.compiler.nodes.EndNode;
37 import org.graalvm.compiler.nodes.IfNode;
38 import org.graalvm.compiler.nodes.LogicNode;
39 import org.graalvm.compiler.nodes.MergeNode;
40 import org.graalvm.compiler.nodes.NodeView;
41 import org.graalvm.compiler.nodes.ShortCircuitOrNode;
42 import org.graalvm.compiler.nodes.StructuredGraph;
43 import org.graalvm.compiler.nodes.ValueNode;
44 import org.graalvm.compiler.nodes.calc.AbstractNormalizeCompareNode;
45 import org.graalvm.compiler.nodes.calc.ConditionalNode;
46 import org.graalvm.compiler.phases.Phase;
47
48 public class ExpandLogicPhase extends Phase {
49 private static final double EPSILON = 1E-6;
50
51 @Override
52 @SuppressWarnings("try")
53 protected void run(StructuredGraph graph) {
54 for (ShortCircuitOrNode logic : graph.getNodes(ShortCircuitOrNode.TYPE)) {
55 processBinary(logic);
56 }
57 assert graph.getNodes(ShortCircuitOrNode.TYPE).isEmpty();
58
59 for (AbstractNormalizeCompareNode logic : graph.getNodes(AbstractNormalizeCompareNode.TYPE)) {
60 try (DebugCloseable context = logic.withNodeSourcePosition()) {
61 processNormalizeCompareNode(logic);
62 }
63 }
64 graph.setAfterExpandLogic();
65 }
66
67 private static void processNormalizeCompareNode(AbstractNormalizeCompareNode normalize) {
68 StructuredGraph graph = normalize.graph();
69 LogicNode equalComp = graph.addOrUniqueWithInputs(normalize.createEqualComparison());
70 LogicNode lessComp = graph.addOrUniqueWithInputs(normalize.createLowerComparison());
71 Stamp stamp = normalize.stamp(NodeView.DEFAULT);
72 ConditionalNode equalValue = graph.unique(new ConditionalNode(equalComp, ConstantNode.forIntegerStamp(stamp, 0, graph), ConstantNode.forIntegerStamp(stamp, 1, graph)));
73 ConditionalNode value = graph.unique(new ConditionalNode(lessComp, ConstantNode.forIntegerStamp(stamp, -1, graph), equalValue));
74 normalize.replaceAtUsagesAndDelete(value);
75 }
76
77 @SuppressWarnings("try")
78 private static void processBinary(ShortCircuitOrNode binary) {
79 while (binary.usages().isNotEmpty()) {
80 Node usage = binary.usages().first();
81 try (DebugCloseable nsp = usage.withNodeSourcePosition()) {
82 if (usage instanceof ShortCircuitOrNode) {
83 processBinary((ShortCircuitOrNode) usage);
84 } else if (usage instanceof IfNode) {
85 processIf(binary.getX(), binary.isXNegated(), binary.getY(), binary.isYNegated(), (IfNode) usage, binary.getShortCircuitProbability());
86 } else if (usage instanceof ConditionalNode) {
87 processConditional(binary.getX(), binary.isXNegated(), binary.getY(), binary.isYNegated(), (ConditionalNode) usage);
88 } else {
89 throw GraalError.shouldNotReachHere();
90 }
91 }
92 }
93 binary.safeDelete();
94 }
95
96 private static void processIf(LogicNode x, boolean xNegated, LogicNode y, boolean yNegated, IfNode ifNode, double shortCircuitProbability) {
97 /*
98 * this method splits an IfNode, which has a ShortCircuitOrNode as its condition, into two
99 * separate IfNodes: if(X) and if(Y)
100 *
101 * for computing the probabilities P(X) and P(Y), we use two different approaches. The first
102 * one assumes that the shortCircuitProbability and the probability on the IfNode were
103 * created with each other in mind. If this assumption does not hold, we fall back to
104 * another mechanism for computing the probabilities.
105 */
106 AbstractBeginNode trueTarget = ifNode.trueSuccessor();
107 AbstractBeginNode falseTarget = ifNode.falseSuccessor();
108
109 // 1st approach
110 // assumption: P(originalIf.trueSuccessor) == P(X) + ((1 - P(X)) * P(Y))
111 double firstIfTrueProbability = shortCircuitProbability;
112 double secondIfTrueProbability = sanitizeProbability((ifNode.getTrueSuccessorProbability() - shortCircuitProbability) / (1 - shortCircuitProbability));
113 double expectedOriginalIfTrueProbability = firstIfTrueProbability + (1 - firstIfTrueProbability) * secondIfTrueProbability;
114
115 if (!doubleEquals(ifNode.getTrueSuccessorProbability(), expectedOriginalIfTrueProbability)) {
116 /*
117 * 2nd approach
118 *
119 * the assumption above did not hold, so we either used an artificial probability as
120 * shortCircuitProbability or the ShortCircuitOrNode was moved to some other IfNode.
121 *
122 * so, we distribute the if's trueSuccessorProbability between the newly generated if
123 * nodes according to the shortCircuitProbability. the following invariant is always
124 * true in this case: P(originalIf.trueSuccessor) == P(X) + ((1 - P(X)) * P(Y))
125 */
126 firstIfTrueProbability = ifNode.getTrueSuccessorProbability() * shortCircuitProbability;
127 secondIfTrueProbability = sanitizeProbability(1 - (ifNode.probability(falseTarget) / (1 - firstIfTrueProbability)));
128 }
129
130 ifNode.clearSuccessors();
131 Graph graph = ifNode.graph();
132 AbstractMergeNode trueTargetMerge = graph.add(new MergeNode());
133 trueTargetMerge.setNext(trueTarget);
134 EndNode firstTrueEnd = graph.add(new EndNode());
135 EndNode secondTrueEnd = graph.add(new EndNode());
136 trueTargetMerge.addForwardEnd(firstTrueEnd);
137 trueTargetMerge.addForwardEnd(secondTrueEnd);
138 AbstractBeginNode firstTrueTarget = BeginNode.begin(firstTrueEnd);
139 firstTrueTarget.setNodeSourcePosition(trueTarget.getNodeSourcePosition());
140 AbstractBeginNode secondTrueTarget = BeginNode.begin(secondTrueEnd);
141 secondTrueTarget.setNodeSourcePosition(trueTarget.getNodeSourcePosition());
142 if (yNegated) {
143 secondIfTrueProbability = 1.0 - secondIfTrueProbability;
144 }
145 if (xNegated) {
146 firstIfTrueProbability = 1.0 - firstIfTrueProbability;
147 }
148 IfNode secondIf = new IfNode(y, yNegated ? falseTarget : secondTrueTarget, yNegated ? secondTrueTarget : falseTarget, secondIfTrueProbability);
149 secondIf.setNodeSourcePosition(ifNode.getNodeSourcePosition());
150 AbstractBeginNode secondIfBegin = BeginNode.begin(graph.add(secondIf));
151 secondIfBegin.setNodeSourcePosition(falseTarget.getNodeSourcePosition());
152 IfNode firstIf = graph.add(new IfNode(x, xNegated ? secondIfBegin : firstTrueTarget, xNegated ? firstTrueTarget : secondIfBegin, firstIfTrueProbability));
153 firstIf.setNodeSourcePosition(ifNode.getNodeSourcePosition());
154 ifNode.replaceAtPredecessor(firstIf);
155 ifNode.safeDelete();
156 }
157
158 private static boolean doubleEquals(double a, double b) {
159 assert !Double.isNaN(a) && !Double.isNaN(b) && !Double.isInfinite(a) && !Double.isInfinite(b);
160 return a - EPSILON < b && a + EPSILON > b;
161 }
162
163 private static double sanitizeProbability(double value) {
164 double newValue = Math.min(1.0, Math.max(0.0, value));
165 if (Double.isNaN(newValue)) {
166 newValue = 0.5;
167 }
168 return newValue;
169 }
170
171 @SuppressWarnings("try")
172 private static void processConditional(LogicNode x, boolean xNegated, LogicNode y, boolean yNegated, ConditionalNode conditional) {
173 try (DebugCloseable context = conditional.withNodeSourcePosition()) {
174 ValueNode trueTarget = conditional.trueValue();
175 ValueNode falseTarget = conditional.falseValue();
176 Graph graph = conditional.graph();
177 ConditionalNode secondConditional = graph.unique(new ConditionalNode(y, yNegated ? falseTarget : trueTarget, yNegated ? trueTarget : falseTarget));
178 ConditionalNode firstConditional = graph.unique(new ConditionalNode(x, xNegated ? secondConditional : trueTarget, xNegated ? trueTarget : secondConditional));
179 conditional.replaceAndDelete(firstConditional);
180 }
181 }
182
183 @Override
184 public boolean checkContract() {
185 return false;
186 }
187 }