Imported WebKit commit bb52bf3c0119e8a128cd93afe5572413a8617de9 (http://svn.webkit.org/repository/webkit/trunk@108790)

1 files changed, 733 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp b/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp
new file mode 100644
index 000000000..a3c27ebc1
--- /dev/null
+++ b/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp
@@ -0,0 +1,733 @@
+/*
+ * Copyright (C) 2011 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "DFGCSEPhase.h"
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGGraph.h"
+#include "DFGPhase.h"
+
+namespace JSC { namespace DFG {
+
+class CSEPhase : public Phase {
+public:
+    CSEPhase(Graph& graph)
+        : Phase(graph, "common subexpression elimination")
+    {
+        // Replacements are used to implement local common subexpression elimination.
+        m_replacements.resize(m_graph.size());
+        
+        for (unsigned i = 0; i < m_graph.size(); ++i)
+            m_replacements[i] = NoNode;
+        
+        for (unsigned i = 0; i < LastNodeId; ++i)
+            m_lastSeen[i] = NoNode;
+    }
+    
+    void run()
+    {
+        for (unsigned block = 0; block < m_graph.m_blocks.size(); ++block)
+            performBlockCSE(*m_graph.m_blocks[block]);
+    }
+    
+private:
+    
+    NodeIndex canonicalize(NodeIndex nodeIndex)
+    {
+        if (nodeIndex == NoNode)
+            return NoNode;
+        
+        if (m_graph[nodeIndex].op == ValueToInt32)
+            nodeIndex = m_graph[nodeIndex].child1().index();
+        
+        return nodeIndex;
+    }
+    NodeIndex canonicalize(NodeUse nodeUse)
+    {
+        return canonicalize(nodeUse.indexUnchecked());
+    }
+    
+    // Computes where the search for a candidate for CSE should start. Don't call
+    // this directly; call startIndex() instead as it does logging in debug mode.
+    NodeIndex computeStartIndexForChildren(NodeIndex child1 = NoNode, NodeIndex child2 = NoNode, NodeIndex child3 = NoNode)
+    {
+        const unsigned limit = 300;
+        
+        NodeIndex start = m_start;
+        if (m_compileIndex - start > limit)
+            start = m_compileIndex - limit;
+        
+        ASSERT(start >= m_start);
+        
+        NodeIndex child = canonicalize(child1);
+        if (child == NoNode)
+            return start;
+        
+        if (start < child)
+            start = child;
+        
+        child = canonicalize(child2);
+        if (child == NoNode)
+            return start;
+        
+        if (start < child)
+            start = child;
+        
+        child = canonicalize(child3);
+        if (child == NoNode)
+            return start;
+        
+        if (start < child)
+            start = child;
+        
+        return start;
+    }
+    
+    NodeIndex startIndexForChildren(NodeIndex child1 = NoNode, NodeIndex child2 = NoNode, NodeIndex child3 = NoNode)
+    {
+        NodeIndex result = computeStartIndexForChildren(child1, child2, child3);
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("  lookback %u: ", result);
+#endif
+        return result;
+    }
+    
+    NodeIndex startIndex()
+    {
+        Node& node = m_graph[m_compileIndex];
+        return startIndexForChildren(
+            node.child1().indexUnchecked(),
+            node.child2().indexUnchecked(),
+            node.child3().indexUnchecked());
+    }
+    
+    NodeIndex endIndexForPureCSE()
+    {
+        NodeIndex result = m_lastSeen[m_graph[m_compileIndex].op & NodeIdMask];
+        if (result == NoNode)
+            result = 0;
+        else
+            result++;
+        ASSERT(result <= m_compileIndex);
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("  limit %u: ", result);
+#endif
+        return result;
+    }
+    
+    NodeIndex pureCSE(Node& node)
+    {
+        NodeIndex child1 = canonicalize(node.child1());
+        NodeIndex child2 = canonicalize(node.child2());
+        NodeIndex child3 = canonicalize(node.child3());
+        
+        NodeIndex start = startIndex();
+        for (NodeIndex index = endIndexForPureCSE(); index-- > start;) {
+            Node& otherNode = m_graph[index];
+            if (node.op != otherNode.op)
+                continue;
+            
+            if (node.arithNodeFlagsForCompare() != otherNode.arithNodeFlagsForCompare())
+                continue;
+            
+            NodeIndex otherChild = canonicalize(otherNode.child1());
+            if (otherChild == NoNode)
+                return index;
+            if (otherChild != child1)
+                continue;
+            
+            otherChild = canonicalize(otherNode.child2());
+            if (otherChild == NoNode)
+                return index;
+            if (otherChild != child2)
+                continue;
+            
+            otherChild = canonicalize(otherNode.child3());
+            if (otherChild == NoNode)
+                return index;
+            if (otherChild != child3)
+                continue;
+            
+            return index;
+        }
+        return NoNode;
+    }
+    
+    bool isPredictedNumerical(Node& node)
+    {
+        PredictedType left = m_graph[node.child1()].prediction();
+        PredictedType right = m_graph[node.child2()].prediction();
+        return isNumberPrediction(left) && isNumberPrediction(right);
+    }
+    
+    bool logicalNotIsPure(Node& node)
+    {
+        PredictedType prediction = m_graph[node.child1()].prediction();
+        return isBooleanPrediction(prediction) || !prediction;
+    }
+    
+    bool byValIsPure(Node& node)
+    {
+        return m_graph[node.child2()].shouldSpeculateInteger()
+            && ((node.op == PutByVal || node.op == PutByValAlias)
+                ? isActionableMutableArrayPrediction(m_graph[node.child1()].prediction())
+                : isActionableArrayPrediction(m_graph[node.child1()].prediction()));
+    }
+    
+    bool clobbersWorld(NodeIndex nodeIndex)
+    {
+        Node& node = m_graph[nodeIndex];
+        if (node.op & NodeClobbersWorld)
+            return true;
+        if (!(node.op & NodeMightClobber))
+            return false;
+        switch (node.op) {
+        case ValueAdd:
+        case CompareLess:
+        case CompareLessEq:
+        case CompareGreater:
+        case CompareGreaterEq:
+        case CompareEq:
+            return !isPredictedNumerical(node);
+        case LogicalNot:
+            return !logicalNotIsPure(node);
+        case GetByVal:
+            return !byValIsPure(node);
+        default:
+            ASSERT_NOT_REACHED();
+            return true; // If by some oddity we hit this case in release build it's safer to have CSE assume the worst.
+        }
+    }
+    
+    NodeIndex impureCSE(Node& node)
+    {
+        NodeIndex child1 = canonicalize(node.child1());
+        NodeIndex child2 = canonicalize(node.child2());
+        NodeIndex child3 = canonicalize(node.child3());
+        
+        NodeIndex start = startIndex();
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& otherNode = m_graph[index];
+            if (node.op == otherNode.op
+                && node.arithNodeFlagsForCompare() == otherNode.arithNodeFlagsForCompare()) {
+                NodeIndex otherChild = canonicalize(otherNode.child1());
+                if (otherChild == NoNode)
+                    return index;
+                if (otherChild == child1) {
+                    otherChild = canonicalize(otherNode.child2());
+                    if (otherChild == NoNode)
+                        return index;
+                    if (otherChild == child2) {
+                        otherChild = canonicalize(otherNode.child3());
+                        if (otherChild == NoNode)
+                            return index;
+                        if (otherChild == child3)
+                            return index;
+                    }
+                }
+            }
+            if (clobbersWorld(index))
+                break;
+        }
+        return NoNode;
+    }
+    
+    NodeIndex globalVarLoadElimination(unsigned varNumber, JSGlobalObject* globalObject)
+    {
+        NodeIndex start = startIndexForChildren();
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case GetGlobalVar:
+                if (node.varNumber() == varNumber && codeBlock()->globalObjectFor(node.codeOrigin) == globalObject)
+                    return index;
+                break;
+            case PutGlobalVar:
+                if (node.varNumber() == varNumber && codeBlock()->globalObjectFor(node.codeOrigin) == globalObject)
+                    return node.child1().index();
+                break;
+            default:
+                break;
+            }
+            if (clobbersWorld(index))
+                break;
+        }
+        return NoNode;
+    }
+    
+    NodeIndex getByValLoadElimination(NodeIndex child1, NodeIndex child2)
+    {
+        NodeIndex start = startIndexForChildren(child1, child2);
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case GetByVal:
+                if (!byValIsPure(node))
+                    return NoNode;
+                if (node.child1() == child1 && canonicalize(node.child2()) == canonicalize(child2))
+                    return index;
+                break;
+            case PutByVal:
+            case PutByValAlias:
+                if (!byValIsPure(node))
+                    return NoNode;
+                if (node.child1() == child1 && canonicalize(node.child2()) == canonicalize(child2))
+                    return node.child3().index();
+                // We must assume that the PutByVal will clobber the location we're getting from.
+                // FIXME: We can do better; if we know that the PutByVal is accessing an array of a
+                // different type than the GetByVal, then we know that they won't clobber each other.
+                return NoNode;
+            case PutStructure:
+            case PutByOffset:
+                // GetByVal currently always speculates that it's accessing an
+                // array with an integer index, which means that it's impossible
+                // for a structure change or a put to property storage to affect
+                // the GetByVal.
+                break;
+            case ArrayPush:
+                // A push cannot affect previously existing elements in the array.
+                break;
+            default:
+                if (clobbersWorld(index))
+                    return NoNode;
+                break;
+            }
+        }
+        return NoNode;
+    }
+
+    bool checkFunctionElimination(JSFunction* function, NodeIndex child1)
+    {
+        NodeIndex start = startIndexForChildren(child1);
+        for (NodeIndex index = endIndexForPureCSE(); index-- > start;) {
+            Node& node = m_graph[index];
+            if (node.op == CheckFunction && node.child1() == child1 && node.function() == function)
+                return true;
+        }
+        return false;
+    }
+
+    bool checkStructureLoadElimination(const StructureSet& structureSet, NodeIndex child1)
+    {
+        NodeIndex start = startIndexForChildren(child1);
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case CheckStructure:
+                if (node.child1() == child1
+                    && structureSet.isSupersetOf(node.structureSet()))
+                    return true;
+                break;
+                
+            case PutStructure:
+                if (node.child1() == child1
+                    && structureSet.contains(node.structureTransitionData().newStructure))
+                    return true;
+                if (structureSet.contains(node.structureTransitionData().previousStructure))
+                    return false;
+                break;
+                
+            case PutByOffset:
+                // Setting a property cannot change the structure.
+                break;
+                
+            case PutByVal:
+            case PutByValAlias:
+                if (byValIsPure(node)) {
+                    // If PutByVal speculates that it's accessing an array with an
+                    // integer index, then it's impossible for it to cause a structure
+                    // change.
+                    break;
+                }
+                return false;
+                
+            default:
+                if (clobbersWorld(index))
+                    return false;
+                break;
+            }
+        }
+        return false;
+    }
+    
+    NodeIndex getByOffsetLoadElimination(unsigned identifierNumber, NodeIndex child1)
+    {
+        NodeIndex start = startIndexForChildren(child1);
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case GetByOffset:
+                if (node.child1() == child1
+                    && m_graph.m_storageAccessData[node.storageAccessDataIndex()].identifierNumber == identifierNumber)
+                    return index;
+                break;
+                
+            case PutByOffset:
+                if (m_graph.m_storageAccessData[node.storageAccessDataIndex()].identifierNumber == identifierNumber) {
+                    if (node.child2() == child1)
+                        return node.child3().index();
+                    return NoNode;
+                }
+                break;
+                
+            case PutStructure:
+                // Changing the structure cannot change the outcome of a property get.
+                break;
+                
+            case PutByVal:
+            case PutByValAlias:
+                if (byValIsPure(node)) {
+                    // If PutByVal speculates that it's accessing an array with an
+                    // integer index, then it's impossible for it to cause a structure
+                    // change.
+                    break;
+                }
+                return NoNode;
+                
+            default:
+                if (clobbersWorld(index))
+                    return NoNode;
+                break;
+            }
+        }
+        return NoNode;
+    }
+    
+    NodeIndex getPropertyStorageLoadElimination(NodeIndex child1)
+    {
+        NodeIndex start = startIndexForChildren(child1);
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case GetPropertyStorage:
+                if (node.child1() == child1)
+                    return index;
+                break;
+                
+            case PutByOffset:
+            case PutStructure:
+                // Changing the structure or putting to the storage cannot
+                // change the property storage pointer.
+                break;
+                
+            case PutByVal:
+            case PutByValAlias:
+                if (byValIsPure(node)) {
+                    // If PutByVal speculates that it's accessing an array with an
+                    // integer index, then it's impossible for it to cause a structure
+                    // change.
+                    break;
+                }
+                return NoNode;
+                
+            default:
+                if (clobbersWorld(index))
+                    return NoNode;
+                break;
+            }
+        }
+        return NoNode;
+    }
+
+    NodeIndex getIndexedPropertyStorageLoadElimination(NodeIndex child1, bool hasIntegerIndexPrediction)
+    {
+        NodeIndex start = startIndexForChildren(child1);
+        for (NodeIndex index = m_compileIndex; index-- > start;) {
+            Node& node = m_graph[index];
+            switch (node.op) {
+            case GetIndexedPropertyStorage: {
+                PredictedType basePrediction = m_graph[node.child2()].prediction();
+                bool nodeHasIntegerIndexPrediction = !(!(basePrediction & PredictInt32) && basePrediction);
+                if (node.child1() == child1 && hasIntegerIndexPrediction == nodeHasIntegerIndexPrediction)
+                    return index;
+                break;
+            }
+
+            case PutByOffset:
+            case PutStructure:
+                // Changing the structure or putting to the storage cannot
+                // change the property storage pointer.
+                break;
+                
+            case PutByValAlias:
+                // PutByValAlias can't change the indexed storage pointer
+                break;
+                
+            case PutByVal:
+                if (isFixedIndexedStorageObjectPrediction(m_graph[node.child1()].prediction()) && byValIsPure(node))
+                    break;
+                return NoNode;
+
+            default:
+                if (clobbersWorld(index))
+                    return NoNode;
+                break;
+            }
+        }
+        return NoNode;
+    }
+    
+    NodeIndex getScopeChainLoadElimination(unsigned depth)
+    {
+        NodeIndex start = startIndexForChildren();
+        for (NodeIndex index = endIndexForPureCSE(); index-- > start;) {
+            Node& node = m_graph[index];
+            if (node.op == GetScopeChain
+                && node.scopeChainDepth() == depth)
+                return index;
+        }
+        return NoNode;
+    }
+    
+    void performSubstitution(NodeUse& child, bool addRef = true)
+    {
+        // Check if this operand is actually unused.
+        if (!child)
+            return;
+        
+        // Check if there is any replacement.
+        NodeIndex replacement = m_replacements[child.index()];
+        if (replacement == NoNode)
+            return;
+        
+        child.setIndex(replacement);
+        
+        // There is definitely a replacement. Assert that the replacement does not
+        // have a replacement.
+        ASSERT(m_replacements[child.index()] == NoNode);
+        
+        if (addRef)
+            m_graph[child].ref();
+    }
+    
+    void setReplacement(NodeIndex replacement)
+    {
+        if (replacement == NoNode)
+            return;
+        
+        // Be safe. Don't try to perform replacements if the predictions don't
+        // agree.
+        if (m_graph[m_compileIndex].prediction() != m_graph[replacement].prediction())
+            return;
+        
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("   Replacing @%u -> @%u", m_compileIndex, replacement);
+#endif
+        
+        Node& node = m_graph[m_compileIndex];
+        node.op = Phantom;
+        node.setRefCount(1);
+        
+        // At this point we will eliminate all references to this node.
+        m_replacements[m_compileIndex] = replacement;
+    }
+    
+    void eliminate()
+    {
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("   Eliminating @%u", m_compileIndex);
+#endif
+        
+        Node& node = m_graph[m_compileIndex];
+        ASSERT(node.refCount() == 1);
+        ASSERT(node.mustGenerate());
+        node.op = Phantom;
+    }
+    
+    void performNodeCSE(Node& node)
+    {
+        bool shouldGenerate = node.shouldGenerate();
+
+        if (node.op & NodeHasVarArgs) {
+            for (unsigned childIdx = node.firstChild(); childIdx < node.firstChild() + node.numChildren(); childIdx++)
+                performSubstitution(m_graph.m_varArgChildren[childIdx], shouldGenerate);
+        } else {
+            performSubstitution(node.children.child1(), shouldGenerate);
+            performSubstitution(node.children.child2(), shouldGenerate);
+            performSubstitution(node.children.child3(), shouldGenerate);
+        }
+        
+        if (!shouldGenerate)
+            return;
+        
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("   %s @%u: ", Graph::opName(m_graph[m_compileIndex].op), m_compileIndex);
+#endif
+        
+        // NOTE: there are some nodes that we deliberately don't CSE even though we
+        // probably could, like StrCat and ToPrimitive. That's because there is no
+        // evidence that doing CSE on these nodes would result in a performance
+        // progression. Hence considering these nodes in CSE would just mean that this
+        // code does more work with no win. Of course, we may want to reconsider this,
+        // since StrCat is trivially CSE-able. It's not trivially doable for
+        // ToPrimitive, but we could change that with some speculations if we really
+        // needed to.
+        
+        switch (node.op) {
+        
+        // Handle the pure nodes. These nodes never have any side-effects.
+        case BitAnd:
+        case BitOr:
+        case BitXor:
+        case BitRShift:
+        case BitLShift:
+        case BitURShift:
+        case ArithAdd:
+        case ArithSub:
+        case ArithMul:
+        case ArithMod:
+        case ArithDiv:
+        case ArithAbs:
+        case ArithMin:
+        case ArithMax:
+        case ArithSqrt:
+        case GetByteArrayLength:
+        case GetInt8ArrayLength:
+        case GetInt16ArrayLength:
+        case GetInt32ArrayLength:
+        case GetUint8ArrayLength:
+        case GetUint8ClampedArrayLength:
+        case GetUint16ArrayLength:
+        case GetUint32ArrayLength:
+        case GetFloat32ArrayLength:
+        case GetFloat64ArrayLength:
+        case GetCallee:
+        case GetStringLength:
+        case StringCharAt:
+        case StringCharCodeAt:
+            setReplacement(pureCSE(node));
+            break;
+            
+        case GetArrayLength:
+            setReplacement(impureCSE(node));
+            break;
+            
+        case GetScopeChain:
+            setReplacement(getScopeChainLoadElimination(node.scopeChainDepth()));
+            break;
+
+        // Handle nodes that are conditionally pure: these are pure, and can
+        // be CSE'd, so long as the prediction is the one we want.
+        case ValueAdd:
+        case CompareLess:
+        case CompareLessEq:
+        case CompareGreater:
+        case CompareGreaterEq:
+        case CompareEq: {
+            if (isPredictedNumerical(node)) {
+                NodeIndex replacementIndex = pureCSE(node);
+                if (replacementIndex != NoNode && isPredictedNumerical(m_graph[replacementIndex]))
+                    setReplacement(replacementIndex);
+            }
+            break;
+        }
+            
+        case LogicalNot: {
+            if (logicalNotIsPure(node)) {
+                NodeIndex replacementIndex = pureCSE(node);
+                if (replacementIndex != NoNode && logicalNotIsPure(m_graph[replacementIndex]))
+                    setReplacement(replacementIndex);
+            }
+            break;
+        }
+            
+        // Finally handle heap accesses. These are not quite pure, but we can still
+        // optimize them provided that some subtle conditions are met.
+        case GetGlobalVar:
+            setReplacement(globalVarLoadElimination(node.varNumber(), codeBlock()->globalObjectFor(node.codeOrigin)));
+            break;
+            
+        case GetByVal:
+            if (byValIsPure(node))
+                setReplacement(getByValLoadElimination(node.child1().index(), node.child2().index()));
+            break;
+            
+        case PutByVal:
+            if (byValIsPure(node) && getByValLoadElimination(node.child1().index(), node.child2().index()) != NoNode)
+                node.op = PutByValAlias;
+            break;
+            
+        case CheckStructure:
+            if (checkStructureLoadElimination(node.structureSet(), node.child1().index()))
+                eliminate();
+            break;
+
+        case CheckFunction:
+            if (checkFunctionElimination(node.function(), node.child1().index()))
+                eliminate();
+            break;
+                
+        case GetIndexedPropertyStorage: {
+            PredictedType basePrediction = m_graph[node.child2()].prediction();
+            bool nodeHasIntegerIndexPrediction = !(!(basePrediction & PredictInt32) && basePrediction);
+            setReplacement(getIndexedPropertyStorageLoadElimination(node.child1().index(), nodeHasIntegerIndexPrediction));
+            break;
+        }
+
+        case GetPropertyStorage:
+            setReplacement(getPropertyStorageLoadElimination(node.child1().index()));
+            break;
+
+        case GetByOffset:
+            setReplacement(getByOffsetLoadElimination(m_graph.m_storageAccessData[node.storageAccessDataIndex()].identifierNumber, node.child1().index()));
+            break;
+            
+        default:
+            // do nothing.
+            break;
+        }
+        
+        m_lastSeen[node.op & NodeIdMask] = m_compileIndex;
+#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
+        dataLog("\n");
+#endif
+    }
+    
+    void performBlockCSE(BasicBlock& block)
+    {
+        m_start = block.begin;
+        NodeIndex end = block.end;
+        for (m_compileIndex = m_start; m_compileIndex < end; ++m_compileIndex)
+            performNodeCSE(m_graph[m_compileIndex]);
+    }
+    
+    NodeIndex m_start;
+    NodeIndex m_compileIndex;
+    Vector<NodeIndex, 16> m_replacements;
+    FixedArray<NodeIndex, LastNodeId> m_lastSeen;
+};
+
+void performCSE(Graph& graph)
+{
+    runPhase<CSEPhase>(graph);
+}
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)
+
+