| /* |
| * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| |
| package org.graalvm.compiler.nodes; |
| |
| import static org.graalvm.compiler.nodeinfo.InputType.Condition; |
| import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0; |
| import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0; |
| |
| import org.graalvm.compiler.core.common.type.IntegerStamp; |
| import org.graalvm.compiler.graph.IterableNodeType; |
| import org.graalvm.compiler.graph.NodeClass; |
| import org.graalvm.compiler.graph.spi.Canonicalizable; |
| import org.graalvm.compiler.graph.spi.CanonicalizerTool; |
| import org.graalvm.compiler.nodeinfo.NodeInfo; |
| import org.graalvm.compiler.nodes.calc.IntegerBelowNode; |
| import org.graalvm.compiler.nodes.calc.IntegerLessThanNode; |
| |
| import jdk.vm.ci.meta.TriState; |
| |
| @NodeInfo(cycles = CYCLES_0, size = SIZE_0) |
| public final class ShortCircuitOrNode extends LogicNode implements IterableNodeType, Canonicalizable.Binary<LogicNode> { |
| public static final NodeClass<ShortCircuitOrNode> TYPE = NodeClass.create(ShortCircuitOrNode.class); |
| @Input(Condition) LogicNode x; |
| @Input(Condition) LogicNode y; |
| protected boolean xNegated; |
| protected boolean yNegated; |
| protected double shortCircuitProbability; |
| |
| public ShortCircuitOrNode(LogicNode x, boolean xNegated, LogicNode y, boolean yNegated, double shortCircuitProbability) { |
| super(TYPE); |
| this.x = x; |
| this.xNegated = xNegated; |
| this.y = y; |
| this.yNegated = yNegated; |
| this.shortCircuitProbability = shortCircuitProbability; |
| } |
| |
| @Override |
| public LogicNode getX() { |
| return x; |
| } |
| |
| @Override |
| public LogicNode getY() { |
| return y; |
| } |
| |
| public boolean isXNegated() { |
| return xNegated; |
| } |
| |
| public boolean isYNegated() { |
| return yNegated; |
| } |
| |
| /** |
| * Gets the probability that the {@link #getY() y} part of this binary node is <b>not</b> |
| * evaluated. This is the probability that this operator will short-circuit its execution. |
| */ |
| public double getShortCircuitProbability() { |
| return shortCircuitProbability; |
| } |
| |
| protected ShortCircuitOrNode canonicalizeNegation(LogicNode forX, LogicNode forY) { |
| LogicNode xCond = forX; |
| boolean xNeg = xNegated; |
| while (xCond instanceof LogicNegationNode) { |
| xCond = ((LogicNegationNode) xCond).getValue(); |
| xNeg = !xNeg; |
| } |
| |
| LogicNode yCond = forY; |
| boolean yNeg = yNegated; |
| while (yCond instanceof LogicNegationNode) { |
| yCond = ((LogicNegationNode) yCond).getValue(); |
| yNeg = !yNeg; |
| } |
| |
| if (xCond != forX || yCond != forY) { |
| return new ShortCircuitOrNode(xCond, xNeg, yCond, yNeg, shortCircuitProbability); |
| } else { |
| return this; |
| } |
| } |
| |
| @Override |
| public LogicNode canonical(CanonicalizerTool tool, LogicNode forX, LogicNode forY) { |
| ShortCircuitOrNode ret = canonicalizeNegation(forX, forY); |
| if (ret != this) { |
| return ret; |
| } |
| |
| if (forX == forY) { |
| // @formatter:off |
| // a || a = a |
| // a || !a = true |
| // !a || a = true |
| // !a || !a = !a |
| // @formatter:on |
| if (isXNegated()) { |
| if (isYNegated()) { |
| // !a || !a = !a |
| return LogicNegationNode.create(forX); |
| } else { |
| // !a || a = true |
| return LogicConstantNode.tautology(); |
| } |
| } else { |
| if (isYNegated()) { |
| // a || !a = true |
| return LogicConstantNode.tautology(); |
| } else { |
| // a || a = a |
| return forX; |
| } |
| } |
| } |
| if (forX instanceof LogicConstantNode) { |
| if (((LogicConstantNode) forX).getValue() ^ isXNegated()) { |
| return LogicConstantNode.tautology(); |
| } else { |
| if (isYNegated()) { |
| return new LogicNegationNode(forY); |
| } else { |
| return forY; |
| } |
| } |
| } |
| if (forY instanceof LogicConstantNode) { |
| if (((LogicConstantNode) forY).getValue() ^ isYNegated()) { |
| return LogicConstantNode.tautology(); |
| } else { |
| if (isXNegated()) { |
| return new LogicNegationNode(forX); |
| } else { |
| return forX; |
| } |
| } |
| } |
| |
| if (forX instanceof ShortCircuitOrNode) { |
| ShortCircuitOrNode inner = (ShortCircuitOrNode) forX; |
| if (forY == inner.getX()) { |
| return optimizeShortCircuit(inner, this.xNegated, this.yNegated, true); |
| } else if (forY == inner.getY()) { |
| return optimizeShortCircuit(inner, this.xNegated, this.yNegated, false); |
| } |
| } else if (forY instanceof ShortCircuitOrNode) { |
| ShortCircuitOrNode inner = (ShortCircuitOrNode) forY; |
| if (inner.getX() == forX) { |
| return optimizeShortCircuit(inner, this.yNegated, this.xNegated, true); |
| } else if (inner.getY() == forX) { |
| return optimizeShortCircuit(inner, this.yNegated, this.xNegated, false); |
| } |
| } |
| |
| // !X => Y constant |
| TriState impliedForY = forX.implies(!isXNegated(), forY); |
| if (impliedForY.isKnown()) { |
| boolean yResult = impliedForY.toBoolean() ^ isYNegated(); |
| return yResult |
| ? LogicConstantNode.tautology() |
| : (isXNegated() |
| ? LogicNegationNode.create(forX) |
| : forX); |
| } |
| |
| // if X >= 0: |
| // u < 0 || X < u ==>> X |<| u |
| if (!isXNegated() && !isYNegated()) { |
| LogicNode sym = simplifyComparison(forX, forY); |
| if (sym != null) { |
| return sym; |
| } |
| } |
| |
| // if X >= 0: |
| // X |<| u || X < u ==>> X |<| u |
| if (forX instanceof IntegerBelowNode && forY instanceof IntegerLessThanNode && !isXNegated() && !isYNegated()) { |
| IntegerBelowNode xNode = (IntegerBelowNode) forX; |
| IntegerLessThanNode yNode = (IntegerLessThanNode) forY; |
| ValueNode xxNode = xNode.getX(); // X >= 0 |
| ValueNode yxNode = yNode.getX(); // X >= 0 |
| if (xxNode == yxNode && ((IntegerStamp) xxNode.stamp(NodeView.DEFAULT)).isPositive()) { |
| ValueNode xyNode = xNode.getY(); // u |
| ValueNode yyNode = yNode.getY(); // u |
| if (xyNode == yyNode) { |
| return forX; |
| } |
| } |
| } |
| |
| // if X >= 0: |
| // u < 0 || (X < u || tail) ==>> X |<| u || tail |
| if (forY instanceof ShortCircuitOrNode && !isXNegated() && !isYNegated()) { |
| ShortCircuitOrNode yNode = (ShortCircuitOrNode) forY; |
| if (!yNode.isXNegated()) { |
| LogicNode sym = simplifyComparison(forX, yNode.getX()); |
| if (sym != null) { |
| double p1 = getShortCircuitProbability(); |
| double p2 = yNode.getShortCircuitProbability(); |
| return new ShortCircuitOrNode(sym, isXNegated(), yNode.getY(), yNode.isYNegated(), p1 + (1 - p1) * p2); |
| } |
| } |
| } |
| |
| return this; |
| } |
| |
| private static LogicNode simplifyComparison(LogicNode forX, LogicNode forY) { |
| LogicNode sym = simplifyComparisonOrdered(forX, forY); |
| if (sym == null) { |
| return simplifyComparisonOrdered(forY, forX); |
| } |
| return sym; |
| } |
| |
| private static LogicNode simplifyComparisonOrdered(LogicNode forX, LogicNode forY) { |
| // if X is >= 0: |
| // u < 0 || X < u ==>> X |<| u |
| if (forX instanceof IntegerLessThanNode && forY instanceof IntegerLessThanNode) { |
| IntegerLessThanNode xNode = (IntegerLessThanNode) forX; |
| IntegerLessThanNode yNode = (IntegerLessThanNode) forY; |
| ValueNode xyNode = xNode.getY(); // 0 |
| if (xyNode.isConstant() && IntegerStamp.OPS.getAdd().isNeutral(xyNode.asConstant())) { |
| ValueNode yxNode = yNode.getX(); // X >= 0 |
| IntegerStamp stamp = (IntegerStamp) yxNode.stamp(NodeView.DEFAULT); |
| if (stamp.isPositive()) { |
| if (xNode.getX() == yNode.getY()) { |
| ValueNode u = xNode.getX(); |
| return IntegerBelowNode.create(yxNode, u, NodeView.DEFAULT); |
| } |
| } |
| } |
| } |
| |
| return null; |
| } |
| |
| private static LogicNode optimizeShortCircuit(ShortCircuitOrNode inner, boolean innerNegated, boolean matchNegated, boolean matchIsInnerX) { |
| boolean innerMatchNegated; |
| if (matchIsInnerX) { |
| innerMatchNegated = inner.isXNegated(); |
| } else { |
| innerMatchNegated = inner.isYNegated(); |
| } |
| if (!innerNegated) { |
| // The four digit results of the expression used in the 16 subsequent formula comments |
| // correspond to results when using the following truth table for inputs a and b |
| // and testing all 4 possible input combinations: |
| // _ 1234 |
| // a 1100 |
| // b 1010 |
| if (innerMatchNegated == matchNegated) { |
| // ( (!a ||!b) ||!a) => 0111 (!a ||!b) |
| // ( (!a || b) ||!a) => 1011 (!a || b) |
| // ( ( a ||!b) || a) => 1101 ( a ||!b) |
| // ( ( a || b) || a) => 1110 ( a || b) |
| // Only the inner or is relevant, the outer or never adds information. |
| return inner; |
| } else { |
| // ( ( a || b) ||!a) => 1111 (true) |
| // ( (!a ||!b) || a) => 1111 (true) |
| // ( (!a || b) || a) => 1111 (true) |
| // ( ( a ||!b) ||!a) => 1111 (true) |
| // The result of the expression is always true. |
| return LogicConstantNode.tautology(); |
| } |
| } else { |
| if (innerMatchNegated == matchNegated) { |
| // (!(!a ||!b) ||!a) => 1011 (!a || b) |
| // (!(!a || b) ||!a) => 0111 (!a ||!b) |
| // (!( a ||!b) || a) => 1110 ( a || b) |
| // (!( a || b) || a) => 1101 ( a ||!b) |
| boolean newInnerXNegated = inner.isXNegated(); |
| boolean newInnerYNegated = inner.isYNegated(); |
| double newProbability = inner.getShortCircuitProbability(); |
| if (matchIsInnerX) { |
| newInnerYNegated = !newInnerYNegated; |
| } else { |
| newInnerXNegated = !newInnerXNegated; |
| newProbability = 1.0 - newProbability; |
| } |
| // The expression can be transformed into a single or. |
| return new ShortCircuitOrNode(inner.getX(), newInnerXNegated, inner.getY(), newInnerYNegated, newProbability); |
| } else { |
| // (!(!a ||!b) || a) => 1100 (a) |
| // (!(!a || b) || a) => 1100 (a) |
| // (!( a ||!b) ||!a) => 0011 (!a) |
| // (!( a || b) ||!a) => 0011 (!a) |
| LogicNode result = inner.getY(); |
| if (matchIsInnerX) { |
| result = inner.getX(); |
| } |
| // Only the second part of the outer or is relevant. |
| if (matchNegated) { |
| return LogicNegationNode.create(result); |
| } else { |
| return result; |
| } |
| } |
| } |
| } |
| } |
