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changeset 23237:46db8e4d2ee0

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Move loop phi recursive usage optimization from loop begin simplification to loop phi canonicalization.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Fri, 01 Jan 2016 18:32:58 +0100
parents 4b117cc6ae9c
children bc992c49ca71
files graal/com.oracle.graal.loop.phases/src/com/oracle/graal/loop/phases/LoopTransformations.java graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PhiNode.java
diffstat 3 files changed, 19 insertions(+), 35 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.loop.phases/src/com/oracle/graal/loop/phases/LoopTransformations.java	Fri Jan 01 18:14:07 2016 +0100
+++ b/graal/com.oracle.graal.loop.phases/src/com/oracle/graal/loop/phases/LoopTransformations.java	Fri Jan 01 18:32:58 2016 +0100
@@ -65,7 +65,6 @@
             Mark mark = graph.getMark();
             peel(loop);
             canonicalizer.applyIncremental(graph, context, mark);
-            loopBegin.removeDeadPhis();
             loop.invalidateFragments();
             if (graph.getNodeCount() > MaximumDesiredSize.getValue() * 3) {
                 throw new BailoutException("FullUnroll : Graph seems to grow out of proportion");
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java	Fri Jan 01 18:14:07 2016 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java	Fri Jan 01 18:32:58 2016 +0100
@@ -24,14 +24,11 @@
 
 import static com.oracle.graal.graph.iterators.NodePredicates.isNotA;
 
-import java.util.Set;
-
 import com.oracle.graal.compiler.common.type.IntegerStamp;
 import com.oracle.graal.graph.IterableNodeType;
 import com.oracle.graal.graph.Node;
 import com.oracle.graal.graph.NodeClass;
 import com.oracle.graal.graph.iterators.NodeIterable;
-import com.oracle.graal.graph.iterators.NodePredicate;
 import com.oracle.graal.graph.spi.SimplifierTool;
 import com.oracle.graal.nodeinfo.InputType;
 import com.oracle.graal.nodeinfo.NodeInfo;
@@ -220,7 +217,6 @@
 
     @Override
     public void simplify(SimplifierTool tool) {
-        removeDeadPhis();
         canonicalizePhis(tool);
     }
 
@@ -248,30 +244,6 @@
         this.overflowGuard = overflowGuard;
     }
 
-    /**
-     * Removes dead {@linkplain PhiNode phi nodes} hanging from this node.
-     *
-     * This method uses the heuristic that any node which not a phi node of this LoopBeginNode is
-     * alive. This allows the removal of dead phi loops.
-     */
-    public void removeDeadPhis() {
-        if (phis().isNotEmpty()) {
-            Set<PhiNode> alive = Node.newSet();
-            for (PhiNode phi : phis()) {
-                NodePredicate isAlive = u -> !isPhiAtMerge(u) || alive.contains(u);
-                if (phi.usages().filter(isAlive).isNotEmpty()) {
-                    alive.add(phi);
-                    for (PhiNode keptAlive : phi.values().filter(PhiNode.class).filter(isAlive.negate())) {
-                        alive.add(keptAlive);
-                    }
-                }
-            }
-            for (PhiNode phi : phis().filter(((NodePredicate) alive::contains).negate()).snapshot()) {
-                phi.replaceAtUsagesAndDelete(null);
-            }
-        }
-    }
-
     private static final int NO_INCREMENT = Integer.MIN_VALUE;
 
     /**
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PhiNode.java	Fri Jan 01 18:14:07 2016 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PhiNode.java	Fri Jan 01 18:32:58 2016 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2016, 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
@@ -27,6 +27,7 @@
 import jdk.vm.ci.meta.JavaKind;
 
 import com.oracle.graal.compiler.common.type.Stamp;
+import com.oracle.graal.graph.Node;
 import com.oracle.graal.graph.NodeClass;
 import com.oracle.graal.graph.NodeInputList;
 import com.oracle.graal.graph.spi.Canonicalizable;
@@ -199,14 +200,26 @@
 
     @Override
     public ValueNode canonical(CanonicalizerTool tool) {
-        ValueNode singleValue;
+
+        if (isLoopPhi()) {
+            if (singleBackValue() == this) {
+                return firstValue();
+            }
 
-        if (isLoopPhi() && singleBackValue() == this) {
-            singleValue = firstValue();
-        } else {
-            singleValue = singleValue();
+            boolean onlySelfUsage = true;
+            for (Node n : this.usages()) {
+                if (n != this) {
+                    onlySelfUsage = false;
+                    break;
+                }
+            }
+
+            if (onlySelfUsage) {
+                return null;
+            }
         }
 
+        ValueNode singleValue = singleValue();
         if (singleValue != MULTIPLE_VALUES) {
             return singleValue;
         }