[PM/AA] Completely remove the AliasAnalysis::copyValue interface.

No in-tree alias analysis used this facility, and it was not called in
any particularly rigorous way, so it seems unlikely to be correct.

Note that one of the only stateful AA implementations in-tree,
GlobalsModRef is completely broken currently (and any AA passes like it
are equally broken) because Module AA passes are not effectively
invalidated when a function pass that fails to update the AA stack runs.

Ultimately, it doesn't seem like we know how we want to build stateful
AA, and until then trying to support and maintain correctness for an
untested API is essentially impossible. To that end, I'm planning to rip
out all of the update API. It can return if and when we need it and know
how to build it on top of the new pass manager and as part of *tested*
stateful AA implementations in the tree.

Differential Revision: http://reviews.llvm.org/D10889

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241975 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/AliasAnalysis.h

@@ -518,14 +518,6 @@ public:
   ///
   virtual void deleteValue(Value *V);
 
-  /// copyValue - This method should be used whenever a preexisting value in the
-  /// program is copied or cloned, introducing a new value.  Note that analysis
-  /// implementations should tolerate clients that use this method to introduce
-  /// the same value multiple times: if the analysis already knows about a
-  /// value, it should ignore the request.
-  ///
-  virtual void copyValue(Value *From, Value *To);
-
   /// addEscapingUse - This method should be used whenever an escaping use is
   /// added to a pointer value.  Analysis implementations may either return
   /// conservative responses for that value in the future, or may recompute
@@ -541,7 +533,6 @@ public:
   /// above, and it provided as a helper to simplify client code.
   ///
   void replaceWithNewValue(Value *Old, Value *New) {
-    copyValue(Old, New);
     deleteValue(Old);
   }
 };