Mercurial > hg > graal-compiler
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/MergeNode.java @ 5225:a693408f737c
Merge node simplification: Combine merge cascades into a single merge.
author | Andreas Woess <andreas.woess@jku.at> |
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date | Tue, 10 Apr 2012 19:02:04 +0200 |
parents | dfe925845cad |
children | e0f17fb3e7d2 |
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/* * Copyright (c) 2009, 2011, 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 com.oracle.graal.nodes; import static com.oracle.graal.graph.iterators.NodePredicates.*; import com.oracle.graal.debug.*; import com.oracle.graal.graph.*; import com.oracle.graal.graph.iterators.*; import com.oracle.graal.nodes.spi.*; import com.oracle.graal.util.*; /** * Denotes the merging of multiple control-flow paths. */ public class MergeNode extends BeginNode implements Node.IterableNodeType, LIRLowerable { @Input(notDataflow = true) private final NodeInputList<EndNode> ends = new NodeInputList<>(this); @Override public boolean needsStateAfter() { return false; } @Override public void generate(LIRGeneratorTool gen) { gen.visitMerge(this); } public int forwardEndIndex(EndNode end) { return ends.indexOf(end); } public void addForwardEnd(EndNode end) { ends.add(end); } public int forwardEndCount() { return ends.size(); } public EndNode forwardEndAt(int index) { return ends.get(index); } @Override public NodeIterable<EndNode> cfgPredecessors() { return ends; } /** * Determines if a given node is a phi whose {@linkplain PhiNode#merge() merge} is this node. * * @param value the instruction to test * @return {@code true} if {@code value} is a phi and its merge is {@code this} */ public boolean isPhiAtMerge(Node value) { return value instanceof PhiNode && ((PhiNode) value).merge() == this; } /** * Removes the given end from the merge, along with the entries corresponding to this end in the phis connected to the merge. * @param pred the end to remove */ public void removeEnd(EndNode pred) { int predIndex = phiPredecessorIndex(pred); assert predIndex != -1; deleteEnd(pred); for (PhiNode phi : phis()) { phi.removeInput(predIndex); } } protected void deleteEnd(EndNode end) { ends.remove(end); } public void clearEnds() { ends.clear(); } public NodeIterable<EndNode> forwardEnds() { return ends; } public int phiPredecessorCount() { return forwardEndCount(); } public int phiPredecessorIndex(EndNode pred) { return forwardEndIndex(pred); } public EndNode phiPredecessorAt(int index) { return forwardEndAt(index); } public NodeIterable<PhiNode> phis() { return this.usages().filter(PhiNode.class).filter(new NodePredicate() { @Override public boolean apply(Node n) { return ((PhiNode) n).merge() == MergeNode.this; } }); } @Override public NodeIterable<Node> anchored() { return super.anchored().filter(isNotA(PhiNode.class).or(new NodePredicate() { @Override public boolean apply(Node n) { return ((PhiNode) n).merge() != MergeNode.this; } })); } @Override public void simplify(SimplifierTool tool) { FixedNode next = next(); if (next instanceof EndNode) { EndNode origLoopEnd = (EndNode) next; MergeNode merge = origLoopEnd.merge(); if (merge instanceof LoopBeginNode && !(origLoopEnd instanceof LoopEndNode)) { return; } for (PhiNode phi : phis()) { for (Node usage : phi.usages().filter(isNotA(FrameState.class))) { if (!merge.isPhiAtMerge(usage)) { return; } } } FixedNode evacuateAnchoredTo = new ComputeImmediateDominator(this).compute(); Debug.log("Split %s into ends for %s. Evacuate to %s", this, merge, evacuateAnchoredTo); this.prepareDelete(evacuateAnchoredTo); int numEnds = this.forwardEndCount(); StructuredGraph graph = (StructuredGraph) graph(); for (int i = 0; i < numEnds - 1; i++) { EndNode end = forwardEndAt(numEnds - 1 - i); EndNode newEnd; if (merge instanceof LoopBeginNode) { newEnd = graph.add(new LoopEndNode((LoopBeginNode) merge)); } else { newEnd = graph.add(new EndNode()); merge.addForwardEnd(newEnd); } for (PhiNode phi : merge.phis()) { ValueNode v = phi.valueAt(origLoopEnd); ValueNode newInput; if (isPhiAtMerge(v)) { PhiNode endPhi = (PhiNode) v; newInput = endPhi.valueAt(end); } else { newInput = v; } phi.addInput(newInput); } this.removeEnd(end); end.replaceAtPredecessors(newEnd); end.safeDelete(); tool.addToWorkList(newEnd.predecessor()); // ? } graph.reduceTrivialMerge(this); } } }