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diff --git a/contrib/llvm/lib/CodeGen/LiveIntervalUnion.h b/contrib/llvm/lib/CodeGen/LiveIntervalUnion.h
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+//===-- LiveIntervalUnion.h - Live interval union data struct --*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// LiveIntervalUnion is a union of live segments across multiple live virtual
+// registers. This may be used during coalescing to represent a congruence
+// class, or during register allocation to model liveness of a physical
+// register.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_LIVEINTERVALUNION
+#define LLVM_CODEGEN_LIVEINTERVALUNION
+
+#include "llvm/ADT/IntervalMap.h"
+#include "llvm/CodeGen/LiveInterval.h"
+
+#include <algorithm>
+
+namespace llvm {
+
+class MachineLoopRange;
+class TargetRegisterInfo;
+
+#ifndef NDEBUG
+// forward declaration
+template <unsigned Element> class SparseBitVector;
+typedef SparseBitVector<128> LiveVirtRegBitSet;
+#endif
+
+/// Compare a live virtual register segment to a LiveIntervalUnion segment.
+inline bool
+overlap(const LiveRange &VRSeg,
+        const IntervalMap<SlotIndex, LiveInterval*>::const_iterator &LUSeg) {
+  return VRSeg.start < LUSeg.stop() && LUSeg.start() < VRSeg.end;
+}
+
+/// Union of live intervals that are strong candidates for coalescing into a
+/// single register (either physical or virtual depending on the context).  We
+/// expect the constituent live intervals to be disjoint, although we may
+/// eventually make exceptions to handle value-based interference.
+class LiveIntervalUnion {
+  // A set of live virtual register segments that supports fast insertion,
+  // intersection, and removal.
+  // Mapping SlotIndex intervals to virtual register numbers.
+  typedef IntervalMap<SlotIndex, LiveInterval*> LiveSegments;
+
+public:
+  // SegmentIter can advance to the next segment ordered by starting position
+  // which may belong to a different live virtual register. We also must be able
+  // to reach the current segment's containing virtual register.
+  typedef LiveSegments::iterator SegmentIter;
+
+  // LiveIntervalUnions share an external allocator.
+  typedef LiveSegments::Allocator Allocator;
+
+  class Query;
+
+private:
+  const unsigned RepReg;  // representative register number
+  unsigned Tag;           // unique tag for current contents.
+  LiveSegments Segments;  // union of virtual reg segments
+
+public:
+  LiveIntervalUnion(unsigned r, Allocator &a) : RepReg(r), Tag(0), Segments(a)
+    {}
+
+  // Iterate over all segments in the union of live virtual registers ordered
+  // by their starting position.
+  SegmentIter begin() { return Segments.begin(); }
+  SegmentIter end() { return Segments.end(); }
+  SegmentIter find(SlotIndex x) { return Segments.find(x); }
+  bool empty() const { return Segments.empty(); }
+  SlotIndex startIndex() const { return Segments.start(); }
+
+  // Provide public access to the underlying map to allow overlap iteration.
+  typedef LiveSegments Map;
+  const Map &getMap() { return Segments; }
+
+  /// getTag - Return an opaque tag representing the current state of the union.
+  unsigned getTag() const { return Tag; }
+
+  /// changedSince - Return true if the union change since getTag returned tag.
+  bool changedSince(unsigned tag) const { return tag != Tag; }
+
+  // Add a live virtual register to this union and merge its segments.
+  void unify(LiveInterval &VirtReg);
+
+  // Remove a live virtual register's segments from this union.
+  void extract(LiveInterval &VirtReg);
+
+  // Remove all inserted virtual registers.
+  void clear() { Segments.clear(); ++Tag; }
+
+  // Print union, using TRI to translate register names
+  void print(raw_ostream &OS, const TargetRegisterInfo *TRI) const;
+
+#ifndef NDEBUG
+  // Verify the live intervals in this union and add them to the visited set.
+  void verify(LiveVirtRegBitSet& VisitedVRegs);
+#endif
+
+  /// Query interferences between a single live virtual register and a live
+  /// interval union.
+  class Query {
+    LiveIntervalUnion *LiveUnion;
+    LiveInterval *VirtReg;
+    LiveInterval::iterator VirtRegI; // current position in VirtReg
+    SegmentIter LiveUnionI;          // current position in LiveUnion
+    SmallVector<LiveInterval*,4> InterferingVRegs;
+    bool CheckedFirstInterference;
+    bool SeenAllInterferences;
+    bool SeenUnspillableVReg;
+    unsigned Tag, UserTag;
+
+  public:
+    Query(): LiveUnion(), VirtReg(), Tag(0), UserTag(0) {}
+
+    Query(LiveInterval *VReg, LiveIntervalUnion *LIU):
+      LiveUnion(LIU), VirtReg(VReg), CheckedFirstInterference(false),
+      SeenAllInterferences(false), SeenUnspillableVReg(false)
+    {}
+
+    void clear() {
+      LiveUnion = NULL;
+      VirtReg = NULL;
+      InterferingVRegs.clear();
+      CheckedFirstInterference = false;
+      SeenAllInterferences = false;
+      SeenUnspillableVReg = false;
+      Tag = 0;
+      UserTag = 0;
+    }
+
+    void init(unsigned UTag, LiveInterval *VReg, LiveIntervalUnion *LIU) {
+      assert(VReg && LIU && "Invalid arguments");
+      if (UserTag == UTag && VirtReg == VReg &&
+          LiveUnion == LIU && !LIU->changedSince(Tag)) {
+        // Retain cached results, e.g. firstInterference.
+        return;
+      }
+      clear();
+      LiveUnion = LIU;
+      VirtReg = VReg;
+      Tag = LIU->getTag();
+      UserTag = UTag;
+    }
+
+    LiveInterval &virtReg() const {
+      assert(VirtReg && "uninitialized");
+      return *VirtReg;
+    }
+
+    // Does this live virtual register interfere with the union?
+    bool checkInterference() { return collectInterferingVRegs(1); }
+
+    // Count the virtual registers in this union that interfere with this
+    // query's live virtual register, up to maxInterferingRegs.
+    unsigned collectInterferingVRegs(unsigned MaxInterferingRegs = UINT_MAX);
+
+    // Was this virtual register visited during collectInterferingVRegs?
+    bool isSeenInterference(LiveInterval *VReg) const;
+
+    // Did collectInterferingVRegs collect all interferences?
+    bool seenAllInterferences() const { return SeenAllInterferences; }
+
+    // Did collectInterferingVRegs encounter an unspillable vreg?
+    bool seenUnspillableVReg() const { return SeenUnspillableVReg; }
+
+    // Vector generated by collectInterferingVRegs.
+    const SmallVectorImpl<LiveInterval*> &interferingVRegs() const {
+      return InterferingVRegs;
+    }
+
+    /// checkLoopInterference - Return true if there is interference overlapping
+    /// Loop.
+    bool checkLoopInterference(MachineLoopRange*);
+
+  private:
+    Query(const Query&);          // DO NOT IMPLEMENT
+    void operator=(const Query&); // DO NOT IMPLEMENT
+  };
+};
+
+} // end namespace llvm
+
+#endif // !defined(LLVM_CODEGEN_LIVEINTERVALUNION)