diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
--- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp
@@ -283,6 +283,11 @@
       LocIdx Idx = Location.Idx;
       ValueIDNum &VNum = MLocs[Idx.asU64()];
       VarLocs.push_back(VNum);
+
+      // Short-circuit unnecessary preferred location update.
+      if (VLocs.empty())
+        continue;
+
       auto it = ValueToLoc.find(VNum);
       // In order of preference, pick:
       //  * Callee saved registers,