[llvm] [RemoveDIs][DebugInfo][NFC] Add Instruction and convenience functions to DPValue (PR #77896)

[Jeremy Morse via llvm-commits]

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@@ -91,6 +91,9 @@ class DPValue : public ilist_node<DPValue>, private DebugValueUser {
   void removeFromParent();
   void eraseFromParent();
 
+  DPValue *getNextNode() { return &*(++getIterator()); }
+  DPValue *getPrevNode() { return &*(--getIterator()); }
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jmorse wrote:

I'd strongly suggest std::next or std::prev rather than increment operators -- that avoid there being any idea of mutating state.

https://github.com/llvm/llvm-project/pull/77896