diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 8ed1351..bd930d8 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3016,6 +3016,7 @@
   case TargetLowering::C_Memory:
     return 3;
   }
+  llvm_unreachable("Invalid constraint type");
 }
 
 /// Examine constraint type and operand type and determine a weight value.