Mercurial > hg > truffle
diff graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/OptimizeGuardAnchorsPhase.java @ 13680:54ee3d025596
Rename OptimizeGuardAnchors to OptimizeGuardAnchorsPhase
author | Gilles Duboscq <duboscq@ssw.jku.at> |
---|---|
date | Fri, 17 Jan 2014 16:23:18 +0100 |
parents | graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/OptimizeGuardAnchors.java@53977508b27d |
children | 01fdabd19cd5 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/OptimizeGuardAnchorsPhase.java Fri Jan 17 16:23:18 2014 +0100 @@ -0,0 +1,143 @@ +/* + * Copyright (c) 2013, 2013, 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.phases.common; + +import java.util.*; + +import com.oracle.graal.debug.*; +import com.oracle.graal.graph.NodeClass.NodeClassIterator; +import com.oracle.graal.graph.iterators.*; +import com.oracle.graal.nodes.*; +import com.oracle.graal.nodes.cfg.*; +import com.oracle.graal.nodes.extended.*; +import com.oracle.graal.phases.*; + +public class OptimizeGuardAnchorsPhase extends Phase { + private static final DebugMetric metricGuardsAnchorOptimized = Debug.metric("GuardsAnchorOptimized"); + private static final DebugMetric metricGuardsOptimizedAtSplit = Debug.metric("GuardsOptimizedAtSplit"); + + public static class LazyCFG { + private ControlFlowGraph cfg; + private StructuredGraph graph; + + public LazyCFG(StructuredGraph graph) { + this.graph = graph; + } + + public ControlFlowGraph get() { + if (cfg == null) { + cfg = ControlFlowGraph.compute(graph, true, false, true, true); + } + return cfg; + } + } + + @Override + protected void run(StructuredGraph graph) { + LazyCFG cfg = new LazyCFG(graph); + for (AbstractBeginNode begin : graph.getNodes(AbstractBeginNode.class)) { + if (!(begin instanceof StartNode || begin.predecessor() instanceof ControlSplitNode)) { + NodeIterable<GuardNode> guards = begin.guards(); + if (guards.isNotEmpty()) { + AbstractBeginNode newAnchor = computeOptimalAnchor(cfg.get(), begin); + // newAnchor == begin is possible because postdominator computation assumes that + // loops never end + if (newAnchor != begin) { + for (GuardNode guard : guards.snapshot()) { + guard.setGuard(newAnchor); + } + metricGuardsAnchorOptimized.increment(); + } + } + } + } + for (ControlSplitNode controlSplit : graph.getNodes(ControlSplitNode.class)) { + optimizeAtControlSplit(controlSplit, cfg); + } + } + + public static AbstractBeginNode getOptimalAnchor(LazyCFG cfg, AbstractBeginNode begin) { + if (begin instanceof StartNode || begin.predecessor() instanceof ControlSplitNode) { + return begin; + } + return computeOptimalAnchor(cfg.get(), begin); + } + + private static AbstractBeginNode computeOptimalAnchor(ControlFlowGraph cfg, AbstractBeginNode begin) { + Block anchor = cfg.blockFor(begin); + while (anchor.getDominator() != null && anchor.getDominator().getPostdominator() == anchor) { + anchor = anchor.getDominator(); + } + return anchor.getBeginNode(); + } + + private static void optimizeAtControlSplit(ControlSplitNode controlSplit, LazyCFG cfg) { + AbstractBeginNode successor = findMinimumUsagesSuccessor(controlSplit); + int successorCount = controlSplit.successors().count(); + List<GuardNode> otherGuards = new ArrayList<>(successorCount - 1); + for (GuardNode guard : successor.guards().snapshot()) { + if (guard.isDeleted() || guard.condition().usages().count() < successorCount) { + continue; + } + for (GuardNode conditonGuard : guard.condition().usages().filter(GuardNode.class)) { + if (conditonGuard != guard) { + GuardingNode conditonGuardAnchor = conditonGuard.getGuard(); + if (conditonGuardAnchor.asNode().predecessor() == controlSplit && compatibleGuards(guard, conditonGuard)) { + otherGuards.add(conditonGuard); + } + } + } + + if (otherGuards.size() == successorCount - 1) { + AbstractBeginNode anchor = computeOptimalAnchor(cfg.get(), AbstractBeginNode.prevBegin(controlSplit)); + GuardNode newGuard = controlSplit.graph().unique(new GuardNode(guard.condition(), anchor, guard.reason(), guard.action(), guard.negated(), guard.getSpeculation())); + for (GuardNode otherGuard : otherGuards) { + otherGuard.replaceAndDelete(newGuard); + } + guard.replaceAndDelete(newGuard); + metricGuardsOptimizedAtSplit.increment(); + } + otherGuards.clear(); + } + } + + private static boolean compatibleGuards(GuardNode guard, GuardNode conditonGuard) { + return conditonGuard.negated() == guard.negated() && conditonGuard.action() == guard.action() && conditonGuard.reason() == guard.reason() && + conditonGuard.getSpeculation().equals(guard.getSpeculation()); + } + + private static AbstractBeginNode findMinimumUsagesSuccessor(ControlSplitNode controlSplit) { + NodeClassIterator successors = controlSplit.successors().iterator(); + AbstractBeginNode min = (AbstractBeginNode) successors.next(); + int minUsages = min.usages().count(); + while (successors.hasNext()) { + AbstractBeginNode successor = (AbstractBeginNode) successors.next(); + int count = successor.usages().count(); + if (count < minUsages) { + minUsages = count; + min = successor; + } + } + return min; + } +}