Tidy up PMStack. Add a bunch of consts, use std::vector instead of

std::deque, since this is a stack and only supports push/pop on
one end, and remove an unimplemented declaration.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110495 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/LoopPass.h

@@ -19,6 +19,7 @@
 #include "llvm/Pass.h"
 #include "llvm/PassManagers.h"
 #include "llvm/Function.h"
+#include <deque>
 
 namespace llvm {