[Dominators] Change getNode parameter type to const NodeT * (NFC).

[fhahn]

Summary

DominatorTreeBase::getNode does not modify its parameter and this change
allows callers that only have access to const pointers to use it without
casting.

[dblaikie]

Feel free to commit changes like this without review - seems sensible/obvious enough. (in theory you could write a unit test, perhaps? but hardly seems worth it for this change - maybe if an existing test covers this code you could change it to have a const parameter)

[kuhar]

include/llvm/Support/GenericDomTree.h

362

How about this place?

[fhahn]

Thanks, I've committed this and added const to the operator[] type as well as tweaked a test to pass in a const pointer.

include/llvm/Support/GenericDomTree.h

public:
   }
 
   void releaseMemory() { reset(); }
 
   /// getNode - return the (Post)DominatorTree node for the specified basic
   /// block.  This is the same as using operator[] on this class.  The result
   /// may (but is not required to) be null for a forward (backwards)
   /// statically unreachable block.
-  DomTreeNodeBase<NodeT> *getNode(NodeT *BB) const {
+  DomTreeNodeBase<NodeT> *getNode(const NodeT *BB) const {
     auto I = DomTreeNodes.find(BB);
     if (I != DomTreeNodes.end())
       return I->second.get();
     return nullptr;
   }
 
   /// See getNode.
   DomTreeNodeBase<NodeT> *operator[](NodeT *BB) const { return getNode(BB); }
 
   /// getRootNode - This returns the entry node for the CFG of the function.  If
   /// this tree represents the post-dominance relations for a function, however,
   /// this root may be a node with the block == NULL.  This is the case when
   /// there are multiple exit nodes from a particular function.  Consumers of
   /// post-dominance information must be capable of dealing with this
   /// possibility.
   ///