# HG changeset patch
# User Gilles Duboscq <duboscq@ssw.jku.at>
# Date 1333724733 -7200
# Node ID dfe925845cad2a907d21c62f428e3fd1837ab5ae
# Parent  0a53ed842cb8c317b40925ad7789f97aebbf2c72
Improve exacuation of anchored values, use it to fix if and merge simplifications

diff -r 0a53ed842cb8 -r dfe925845cad graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/BeginNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/BeginNode.java	Fri Apr 06 16:03:51 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/BeginNode.java	Fri Apr 06 17:05:33 2012 +0200
@@ -73,17 +73,27 @@
         }
     }
 
-    public void evacuateGuards() {
+    public void evacuateGuards(FixedNode evacuateFrom) {
         if (!usages().isEmpty()) {
-            Node prevBegin = predecessor();
+            Node prevBegin = evacuateFrom;
             assert prevBegin != null;
             while (!(prevBegin instanceof BeginNode)) {
                 prevBegin = prevBegin.predecessor();
             }
-            replaceAtUsages(prevBegin);
+            for (Node anchored : anchored().snapshot()) {
+                anchored.replaceFirstInput(this, prevBegin);
+            }
         }
     }
 
+    public void prepareDelete() {
+        prepareDelete((FixedNode) predecessor());
+    }
+
+    public void prepareDelete(FixedNode evacuateFrom) {
+        evacuateGuards(evacuateFrom);
+    }
+
     @Override
     public boolean verify() {
         assertTrue(predecessor() != null || this == ((StructuredGraph) graph()).start() || this instanceof MergeNode, "begin nodes must be connected");
@@ -98,4 +108,8 @@
     public NodeIterable<GuardNode> guards() {
         return usages().filter(GuardNode.class);
     }
+
+    public NodeIterable<Node> anchored() {
+        return usages();
+    }
 }
diff -r 0a53ed842cb8 -r dfe925845cad graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Fri Apr 06 16:03:51 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/IfNode.java	Fri Apr 06 17:05:33 2012 +0200
@@ -161,14 +161,16 @@
         EndNode falseEnd = (EndNode) falseSuccessor.next();
         assert trueEnd.merge() == falseEnd.merge();
 
+        FixedWithNextNode pred = (FixedWithNextNode) predecessor();
         MergeNode merge = trueEnd.merge();
+        merge.prepareDelete(pred);
         assert merge.usages().isEmpty();
 
         FixedNode next = merge.next();
         merge.setNext(null);
         setTrueSuccessor(null);
         setFalseSuccessor(null);
-        ((FixedWithNextNode) predecessor()).setNext(next);
+        pred.setNext(next);
         safeDelete();
         trueSuccessor.safeDelete();
         falseSuccessor.safeDelete();
diff -r 0a53ed842cb8 -r dfe925845cad graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java	Fri Apr 06 16:03:51 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/LoopBeginNode.java	Fri Apr 06 17:05:33 2012 +0200
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes;
 
+import static com.oracle.graal.graph.iterators.NodePredicates.*;
+
 import java.util.*;
 
 import com.oracle.graal.graph.*;
@@ -49,8 +51,13 @@
         return usages().filter(LoopEndNode.class);
     }
 
+    @Override
+    public NodeIterable<Node> anchored() {
+        return super.anchored().filter(isNotA(LoopEndNode.class));
+    }
+
     public List<LoopEndNode> orderedLoopEnds() {
-        List<LoopEndNode> snapshot = usages().filter(LoopEndNode.class).snapshot();
+        List<LoopEndNode> snapshot = loopEnds().snapshot();
         Collections.sort(snapshot, new Comparator<LoopEndNode>() {
             @Override
             public int compare(LoopEndNode o1, LoopEndNode o2) {
diff -r 0a53ed842cb8 -r dfe925845cad graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/MergeNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/MergeNode.java	Fri Apr 06 16:03:51 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/MergeNode.java	Fri Apr 06 17:05:33 2012 +0200
@@ -28,6 +28,7 @@
 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.
@@ -115,12 +116,22 @@
     }
 
     public NodeIterable<PhiNode> phis() {
-        return this.usages().filter(new NodePredicate() {
+        return this.usages().filter(PhiNode.class).filter(new NodePredicate() {
             @Override
             public boolean apply(Node n) {
-                return n instanceof PhiNode && ((PhiNode) n).merge() == MergeNode.this;
+                return ((PhiNode) n).merge() == MergeNode.this;
             }
-        }).filter(PhiNode.class);
+        });
+    }
+
+    @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
@@ -136,7 +147,9 @@
                     }
                 }
             }
-            Debug.log("Split %s into loop ends for %s", this, begin);
+            FixedNode evacuateAnchoredTo = new ComputeImmediateDominator(this).compute();
+            Debug.log("Split %s into loop ends for %s. Evacuate to %s", this, begin, evacuateAnchoredTo);
+            this.prepareDelete(evacuateAnchoredTo);
             int numEnds = this.forwardEndCount();
             StructuredGraph graph = (StructuredGraph) graph();
             for (int i = 0; i < numEnds - 1; i++) {
diff -r 0a53ed842cb8 -r dfe925845cad graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StructuredGraph.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StructuredGraph.java	Fri Apr 06 16:03:51 2012 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/StructuredGraph.java	Fri Apr 06 17:05:33 2012 +0200
@@ -168,6 +168,9 @@
 
     public void removeFixed(FixedWithNextNode node) {
         assert node != null;
+        if (node instanceof BeginNode) {
+            ((BeginNode) node).prepareDelete();
+        }
         assert node.usages().isEmpty() : node + " " + node.usages();
         FixedNode next = node.next();
         node.setNext(null);
@@ -208,15 +211,11 @@
         assert node.usages().isEmpty();
         assert survivingSuccessor >= 0 && survivingSuccessor < node.blockSuccessorCount() : "invalid surviving successor " + survivingSuccessor + " for " + node;
         BeginNode begin = node.blockSuccessor(survivingSuccessor);
-        begin.evacuateGuards();
-        FixedNode next = begin.next();
-        begin.setNext(null);
         for (int i = 0; i < node.blockSuccessorCount(); i++) {
             node.setBlockSuccessor(i, null);
         }
-        node.replaceAtPredecessors(next);
+        node.replaceAtPredecessors(begin);
         node.safeDelete();
-        begin.safeDelete();
     }
 
     public void removeSplitPropagate(ControlSplitNode node, int survivingSuccessor) {
@@ -224,9 +223,6 @@
         assert node.usages().isEmpty();
         assert survivingSuccessor >= 0 && survivingSuccessor < node.blockSuccessorCount() : "invalid surviving successor " + survivingSuccessor + " for " + node;
         BeginNode begin = node.blockSuccessor(survivingSuccessor);
-        begin.evacuateGuards();
-        FixedNode next = begin.next();
-        begin.setNext(null);
         for (int i = 0; i < node.blockSuccessorCount(); i++) {
             BeginNode successor = node.blockSuccessor(i);
             node.setBlockSuccessor(i, null);
@@ -234,10 +230,9 @@
                 GraphUtil.killCFG(successor);
             }
         }
-        if (next.isAlive()) {
-            node.replaceAtPredecessors(next);
+        if (begin.isAlive()) {
+            node.replaceAtPredecessors(begin);
             node.safeDelete();
-            begin.safeDelete();
         } else {
             assert node.isDeleted();
         }
@@ -257,31 +252,23 @@
         assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
         assert survivingSuccessor >= 0 && survivingSuccessor < node.blockSuccessorCount() : "invalid surviving successor " + survivingSuccessor + " for " + node;
         BeginNode begin = node.blockSuccessor(survivingSuccessor);
-        begin.evacuateGuards();
-        FixedNode next = begin.next();
-        begin.setNext(null);
         for (int i = 0; i < node.blockSuccessorCount(); i++) {
             node.setBlockSuccessor(i, null);
         }
-        replacement.setNext(next);
+        replacement.setNext(begin);
         node.replaceAndDelete(replacement);
-        begin.safeDelete();
     }
 
     public void replaceSplitWithFloating(ControlSplitNode node, FloatingNode replacement, int survivingSuccessor) {
         assert node != null && replacement != null && node.isAlive() && replacement.isAlive() : "cannot replace " + node + " with " + replacement;
         assert survivingSuccessor >= 0 && survivingSuccessor < node.blockSuccessorCount() : "invalid surviving successor " + survivingSuccessor + " for " + node;
         BeginNode begin = node.blockSuccessor(survivingSuccessor);
-        begin.evacuateGuards();
-        FixedNode next = begin.next();
-        begin.setNext(null);
         for (int i = 0; i < node.blockSuccessorCount(); i++) {
             node.setBlockSuccessor(i, null);
         }
-        node.replaceAtPredecessors(next);
+        node.replaceAtPredecessors(begin);
         node.replaceAtUsages(replacement);
         node.safeDelete();
-        begin.safeDelete();
     }
 
     public void addAfterFixed(FixedWithNextNode node, FixedWithNextNode newNode) {
@@ -326,13 +313,7 @@
         FixedNode sux = merge.next();
         FrameState stateAfter = merge.stateAfter();
         // evacuateGuards
-        Node prevBegin = singleEnd.predecessor();
-        assert prevBegin != null;
-        while (!(prevBegin instanceof BeginNode)) {
-            prevBegin = prevBegin.predecessor();
-        }
-        merge.replaceAtUsages(prevBegin);
-
+        merge.prepareDelete((FixedNode) singleEnd.predecessor());
         merge.safeDelete();
         if (stateAfter != null && stateAfter.usages().isEmpty()) {
             stateAfter.safeDelete();