More dead code removal (using -Wunreachable-code)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 5aee483..6768860 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1318,7 +1318,7 @@
     return AM.Scale == 0 || AM.Scale == -1;
   }
 
-  return false;
+  llvm_unreachable("Invalid LSRUse Kind!");
 }
 
 static bool isLegalUse(TargetLowering::AddrMode AM,