2 files changed, 13 insertions, 96 deletions

diff --git a/include/llvm/CodeGen/DAGISelHeader.h b/include/llvm/CodeGen/DAGISelHeader.h
index 4a3d70f..86c86e9 100644
--- a/include/llvm/CodeGen/DAGISelHeader.h
+++ b/include/llvm/CodeGen/DAGISelHeader.h
@@ -21,97 +21,6 @@
 #ifndef LLVM_CODEGEN_DAGISEL_HEADER_H
 #define LLVM_CODEGEN_DAGISEL_HEADER_H
 
-/// ISelPosition - Node iterator marking the current position of
-/// instruction selection as it procedes through the topologically-sorted
-/// node list.
-SelectionDAG::allnodes_iterator ISelPosition;
-
-/// ISelUpdater - helper class to handle updates of the 
-/// instruciton selection graph.
-class VISIBILITY_HIDDEN ISelUpdater : public SelectionDAG::DAGUpdateListener {
-  SelectionDAG::allnodes_iterator &ISelPosition;
-public:
-  explicit ISelUpdater(SelectionDAG::allnodes_iterator &isp)
-    : ISelPosition(isp) {}
-  
-  /// NodeDeleted - Handle nodes deleted from the graph. If the
-  /// node being deleted is the current ISelPosition node, update
-  /// ISelPosition.
-  ///
-  virtual void NodeDeleted(SDNode *N, SDNode *E) {
-    if (ISelPosition == SelectionDAG::allnodes_iterator(N))
-      ++ISelPosition;
-  }
-
-  /// NodeUpdated - Ignore updates for now.
-  virtual void NodeUpdated(SDNode *N) {}
-};
-
-/// ReplaceUses - replace all uses of the old node F with the use
-/// of the new node T.
-DISABLE_INLINE void ReplaceUses(SDValue F, SDValue T) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesOfValueWith(F, T, &ISU);
-}
-
-/// ReplaceUses - replace all uses of the old nodes F with the use
-/// of the new nodes T.
-DISABLE_INLINE void ReplaceUses(const SDValue *F, const SDValue *T,
-                                unsigned Num) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesOfValuesWith(F, T, Num, &ISU);
-}
-
-/// ReplaceUses - replace all uses of the old node F with the use
-/// of the new node T.
-DISABLE_INLINE void ReplaceUses(SDNode *F, SDNode *T) {
-  ISelUpdater ISU(ISelPosition);
-  CurDAG->ReplaceAllUsesWith(F, T, &ISU);
-}
-
-/// SelectRoot - Top level entry to DAG instruction selector.
-/// Selects instructions starting at the root of the current DAG.
-void SelectRoot(SelectionDAG &DAG) {
-  SelectRootInit();
-
-  // Create a dummy node (which is not added to allnodes), that adds
-  // a reference to the root node, preventing it from being deleted,
-  // and tracking any changes of the root.
-  HandleSDNode Dummy(CurDAG->getRoot());
-  ISelPosition = SelectionDAG::allnodes_iterator(CurDAG->getRoot().getNode());
-  ++ISelPosition;
-
-  // The AllNodes list is now topological-sorted. Visit the
-  // nodes by starting at the end of the list (the root of the
-  // graph) and preceding back toward the beginning (the entry
-  // node).
-  while (ISelPosition != CurDAG->allnodes_begin()) {
-    SDNode *Node = --ISelPosition;
-    // Skip dead nodes. DAGCombiner is expected to eliminate all dead nodes,
-    // but there are currently some corner cases that it misses. Also, this
-    // makes it theoretically possible to disable the DAGCombiner.
-    if (Node->use_empty())
-      continue;
-
-    SDNode *ResNode = Select(Node);
-    
-    // If node should not be replaced, continue with the next one.
-    if (ResNode == Node)
-      continue;
-    // Replace node.
-    if (ResNode)
-      ReplaceUses(Node, ResNode);
-
-    // If after the replacement this node is not used any more,
-    // remove this dead node.
-    if (Node->use_empty()) { // Don't delete EntryToken, etc.
-      ISelUpdater ISU(ISelPosition);
-      CurDAG->RemoveDeadNode(Node, &ISU);
-    }
-  }
-
-  CurDAG->setRoot(Dummy.getValue());
-}
 
 
 #endif /* LLVM_CODEGEN_DAGISEL_HEADER_H */
diff --git a/include/llvm/CodeGen/SelectionDAGISel.h b/include/llvm/CodeGen/SelectionDAGISel.h
index c43eede..a72fa59 100644
--- a/include/llvm/CodeGen/SelectionDAGISel.h
+++ b/include/llvm/CodeGen/SelectionDAGISel.h
@@ -68,12 +68,18 @@ public:
   unsigned MakeReg(EVT VT);
 
   virtual void EmitFunctionEntryCode(Function &Fn, MachineFunction &MF) {}
-  virtual void InstructionSelect() = 0;
   
-  void SelectRootInit() {
-    DAGSize = CurDAG->AssignTopologicalOrder();
-  }
-
+  /// PreprocessISelDAG - This hook allows targets to hack on the graph before
+  /// instruction selection starts.
+  virtual void PreprocessISelDAG() {}
+  
+  /// PostprocessISelDAG() - This hook allows the target to hack on the graph
+  /// right after selection.
+  virtual void PostprocessISelDAG() {}
+  
+  /// Select - Main hook targets implement to select a node.
+  virtual SDNode *Select(SDNode *N) = 0;
+  
   /// SelectInlineAsmMemoryOperand - Select the specified address as a target
   /// addressing mode, according to the specified constraint code.  If this does
   /// not match or is not implemented, return true.  The resultant operands
@@ -268,6 +274,8 @@ protected:
   void CannotYetSelectIntrinsic(SDNode *N);
 
 private:
+  void DoInstructionSelection();
+  
   void SelectAllBasicBlocks(Function &Fn, MachineFunction &MF,
                             MachineModuleInfo *MMI,
                             DwarfWriter *DW,