Add ArrayRef constructor from None, and do the cleanups that this constructor enables

Patch by Robert Wilhelm.

llvm-svn: 181138
GitOrigin-RevId: 3238fb759563e64b3fc1f28bb3e184de3d7b07a1
diff --git a/lib/IR/PassManager.cpp b/lib/IR/PassManager.cpp
index 3c968aa..387094a 100644
--- a/lib/IR/PassManager.cpp
+++ b/lib/IR/PassManager.cpp
@@ -42,14 +42,14 @@
 
 // Different debug levels that can be enabled...
 enum PassDebugLevel {
-  None, Arguments, Structure, Executions, Details
+  Disabled, Arguments, Structure, Executions, Details
 };
 
 static cl::opt<enum PassDebugLevel>
 PassDebugging("debug-pass", cl::Hidden,
                   cl::desc("Print PassManager debugging information"),
                   cl::values(
-  clEnumVal(None      , "disable debug output"),
+  clEnumVal(Disabled  , "disable debug output"),
   clEnumVal(Arguments , "print pass arguments to pass to 'opt'"),
   clEnumVal(Structure , "print pass structure before run()"),
   clEnumVal(Executions, "print pass name before it is executed"),