Index: lib/CodeGen/InlineSpiller.cpp
===================================================================
--- lib/CodeGen/InlineSpiller.cpp
+++ lib/CodeGen/InlineSpiller.cpp
@@ -644,7 +644,10 @@
       continue;
     }
 
-    assert(LIS.hasInterval(Reg) && "Reg with no interval");
+    assert(LIS.hasInterval(Reg) &&
+           (!LIS.getInterval(Reg).empty() || !MRI.reg_nodbg_empty(Reg)) &&
+           "Empty and not used live-range?!");
+
     RegsToSpill[ResultPos++] = Reg;
   }
   RegsToSpill.erase(RegsToSpill.begin() + ResultPos, RegsToSpill.end());
Index: lib/CodeGen/RegAllocBase.cpp
===================================================================
--- lib/CodeGen/RegAllocBase.cpp
+++ lib/CodeGen/RegAllocBase.cpp
@@ -133,11 +133,13 @@
     if (AvailablePhysReg)
       Matrix->assign(*VirtReg, AvailablePhysReg);
 
-    for (VirtRegVec::iterator I = SplitVRegs.begin(), E = SplitVRegs.end();
-         I != E; ++I) {
-      LiveInterval *SplitVirtReg = &LIS->getInterval(*I);
+    for (unsigned Reg : SplitVRegs) {
+      assert(LIS->hasInterval(Reg));
+
+      LiveInterval *SplitVirtReg = &LIS->getInterval(Reg);
       assert(!VRM->hasPhys(SplitVirtReg->reg) && "Register already assigned");
       if (MRI->reg_nodbg_empty(SplitVirtReg->reg)) {
+        assert(SplitVirtReg->empty() && "Non-empty but used interval");
         DEBUG(dbgs() << "not queueing unused  " << *SplitVirtReg << '\n');
         aboutToRemoveInterval(*SplitVirtReg);
         LIS->removeInterval(SplitVirtReg->reg);