Fix some VC++ warnings.

llvm-svn: 35224
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index 262549a..06544bf 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -394,6 +394,7 @@
     if ((*I)->hasType(VT) && (*I)->contains(reg))
       return *I;
   assert(false && "Couldn't find the register class");
+  return 0;
 }
 
 /// EmitNode - Generate machine code for an node and needed dependencies.