Index: include/llvm/CodeGen/CalcSpillWeights.h
===================================================================
--- include/llvm/CodeGen/CalcSpillWeights.h
+++ include/llvm/CodeGen/CalcSpillWeights.h
@@ -20,6 +20,7 @@
   class LiveIntervals;
   class MachineBlockFrequencyInfo;
   class MachineLoopInfo;
+  class VirtRegMap;
 
   /// \brief Normalize the spill weight of a live interval
   ///
@@ -51,6 +52,7 @@
   private:
     MachineFunction &MF;
     LiveIntervals &LIS;
+    VirtRegMap *VRM;
     const MachineLoopInfo &Loops;
     const MachineBlockFrequencyInfo &MBFI;
     DenseMap<unsigned, float> Hint;
@@ -58,10 +60,10 @@
 
   public:
     VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
-                   const MachineLoopInfo &loops,
+                   VirtRegMap *vrm, const MachineLoopInfo &loops,
                    const MachineBlockFrequencyInfo &mbfi,
                    NormalizingFn norm = normalizeSpillWeight)
-        : MF(mf), LIS(lis), Loops(loops), MBFI(mbfi), normalize(norm) {}
+        : MF(mf), LIS(lis), VRM(vrm), Loops(loops), MBFI(mbfi), normalize(norm) {}
 
     /// \brief (re)compute li's spill weight and allocation hint.
     void calculateSpillWeightAndHint(LiveInterval &li);
@@ -70,6 +72,7 @@
   /// \brief Compute spill weights and allocation hints for all virtual register
   /// live intervals.
   void calculateSpillWeightsAndHints(LiveIntervals &LIS, MachineFunction &MF,
+                                     VirtRegMap *VRM,
                                      const MachineLoopInfo &MLI,
                                      const MachineBlockFrequencyInfo &MBFI,
                                      VirtRegAuxInfo::NormalizingFn norm =
Index: lib/CodeGen/CalcSpillWeights.cpp
===================================================================
--- lib/CodeGen/CalcSpillWeights.cpp
+++ lib/CodeGen/CalcSpillWeights.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/CodeGen/VirtRegMap.h"
 #include "llvm/CodeGen/CalcSpillWeights.h"
 #include "llvm/CodeGen/LiveIntervalAnalysis.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
@@ -24,6 +25,7 @@
 
 void llvm::calculateSpillWeightsAndHints(LiveIntervals &LIS,
                            MachineFunction &MF,
+                           VirtRegMap *VRM,
                            const MachineLoopInfo &MLI,
                            const MachineBlockFrequencyInfo &MBFI,
                            VirtRegAuxInfo::NormalizingFn norm) {
@@ -31,7 +33,7 @@
                << "********** Function: " << MF.getName() << '\n');
 
   MachineRegisterInfo &MRI = MF.getRegInfo();
-  VirtRegAuxInfo VRAI(MF, LIS, MLI, MBFI, norm);
+  VirtRegAuxInfo VRAI(MF, LIS, VRM, MLI, MBFI, norm);
   for (unsigned i = 0, e = MRI.getNumVirtRegs(); i != e; ++i) {
     unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
     if (MRI.reg_nodbg_empty(Reg))
@@ -74,7 +76,10 @@
 // Check if all values in LI are rematerializable
 static bool isRematerializable(const LiveInterval &LI,
                                const LiveIntervals &LIS,
+                               VirtRegMap *VRM,
                                const TargetInstrInfo &TII) {
+  unsigned Reg = LI.reg;
+  unsigned Original = VRM ? VRM->getOriginal(Reg) : 0;
   for (LiveInterval::const_vni_iterator I = LI.vni_begin(), E = LI.vni_end();
        I != E; ++I) {
     const VNInfo *VNI = *I;
@@ -86,6 +91,36 @@
     MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
     assert(MI && "Dead valno in interval");
 
+    // Trace copies introduced by live range splitting.  The inline
+    // spiller can rematerialize through these copies, so the spill
+    // weight must reflect this.
+    if (VRM) {
+      while (MI->isFullCopy()) {
+        // The copy destination must match the interval register.
+        if (MI->getOperand(0).getReg() != Reg)
+          return false;
+
+        // Get the source register.
+        Reg = MI->getOperand(1).getReg();
+
+        // If the original (pre-splitting) registers match this
+        // copy came from a split.
+        if (!TargetRegisterInfo::isVirtualRegister(Reg) ||
+            VRM->getOriginal(Reg) != Original)
+          return false;
+
+        // Follow the copy live-in value.
+        const LiveInterval &SrcLI = LIS.getInterval(Reg);
+        LiveQueryResult SrcQ = SrcLI.Query(VNI->def);
+        VNI = SrcQ.valueIn();
+        assert(VNI && "Copy from non-existing value");
+        if (VNI->isPHIDef())
+          return false;
+        MI = LIS.getInstructionFromIndex(VNI->def);
+        assert(MI && "Dead valno in interval");
+      }
+    }
+
     if (!TII.isTriviallyReMaterializable(MI, LIS.getAliasAnalysis()))
       return false;
   }
@@ -188,7 +223,7 @@
   // it is a preferred candidate for spilling.
   // FIXME: this gets much more complicated once we support non-trivial
   // re-materialization.
-  if (isRematerializable(li, LIS, *MF.getSubtarget().getInstrInfo()))
+  if (isRematerializable(li, LIS, VRM, *MF.getSubtarget().getInstrInfo()))
     totalWeight *= 0.5F;
 
   li.weight = normalize(totalWeight, li.getSize(), numInstr);
Index: lib/CodeGen/LiveRangeEdit.cpp
===================================================================
--- lib/CodeGen/LiveRangeEdit.cpp
+++ lib/CodeGen/LiveRangeEdit.cpp
@@ -411,7 +411,7 @@
 LiveRangeEdit::calculateRegClassAndHint(MachineFunction &MF,
                                         const MachineLoopInfo &Loops,
                                         const MachineBlockFrequencyInfo &MBFI) {
-  VirtRegAuxInfo VRAI(MF, LIS, Loops, MBFI);
+  VirtRegAuxInfo VRAI(MF, LIS, VRM, Loops, MBFI);
   for (unsigned I = 0, Size = size(); I < Size; ++I) {
     LiveInterval &LI = LIS.getInterval(get(I));
     if (MRI.recomputeRegClass(LI.reg))
Index: lib/CodeGen/RegAllocBasic.cpp
===================================================================
--- lib/CodeGen/RegAllocBasic.cpp
+++ lib/CodeGen/RegAllocBasic.cpp
@@ -276,7 +276,7 @@
                      getAnalysis<LiveIntervals>(),
                      getAnalysis<LiveRegMatrix>());
 
-  calculateSpillWeightsAndHints(*LIS, *MF,
+  calculateSpillWeightsAndHints(*LIS, *MF, VRM,
                                 getAnalysis<MachineLoopInfo>(),
                                 getAnalysis<MachineBlockFrequencyInfo>());
 
Index: lib/CodeGen/RegAllocGreedy.cpp
===================================================================
--- lib/CodeGen/RegAllocGreedy.cpp
+++ lib/CodeGen/RegAllocGreedy.cpp
@@ -2586,7 +2586,7 @@
 
   initializeCSRCost();
 
-  calculateSpillWeightsAndHints(*LIS, mf, *Loops, *MBFI);
+  calculateSpillWeightsAndHints(*LIS, mf, VRM, *Loops, *MBFI);
 
   DEBUG(LIS->dump());
 
Index: lib/CodeGen/RegAllocPBQP.cpp
===================================================================
--- lib/CodeGen/RegAllocPBQP.cpp
+++ lib/CodeGen/RegAllocPBQP.cpp
@@ -724,11 +724,11 @@
   MachineBlockFrequencyInfo &MBFI =
     getAnalysis<MachineBlockFrequencyInfo>();
 
-  calculateSpillWeightsAndHints(LIS, MF, getAnalysis<MachineLoopInfo>(), MBFI,
-                                normalizePBQPSpillWeight);
-
   VirtRegMap &VRM = getAnalysis<VirtRegMap>();
 
+  calculateSpillWeightsAndHints(LIS, MF, &VRM, getAnalysis<MachineLoopInfo>(),
+                                MBFI, normalizePBQPSpillWeight);
+
   std::unique_ptr<Spiller> VRegSpiller(createInlineSpiller(*this, MF, VRM));
 
   MF.getRegInfo().freezeReservedRegs(MF);