diff --git a/llvm/lib/CodeGen/RegAllocBase.cpp b/llvm/lib/CodeGen/RegAllocBase.cpp
index 93eeb9c..c204665 100644
--- a/llvm/lib/CodeGen/RegAllocBase.cpp
+++ b/llvm/lib/CodeGen/RegAllocBase.cpp
@@ -143,6 +143,7 @@
         continue;
       }
       DEBUG(dbgs() << "queuing new interval: " << *SplitVirtReg << "\n");
+      assert(!SplitVirtReg->empty() && "expecting non-empty interval");
       assert(TargetRegisterInfo::isVirtualRegister(SplitVirtReg->reg) &&
              "expect split value in virtual register");
       enqueue(SplitVirtReg);