DBG_VALUE does not have any side effects; it also makes no sense to mark it cheap as a copy.

llvm-svn: 123031
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index bc2a545..ccb2ffb 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1115,7 +1115,9 @@
     SawStore = true;
     return false;
   }
-  if (TID->isTerminator() || TID->hasUnmodeledSideEffects())
+
+  if (isLabel() || isDebugValue() ||
+      TID->isTerminator() || TID->hasUnmodeledSideEffects())
     return false;
 
   // See if this instruction does a load.  If so, we have to guarantee that the