[llvm] [SelectionDAG] Treat CopyFromReg as freezing the value (PR #85932)

[Matt Arsenault via llvm-commits]

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@@ -205,6 +205,7 @@ enum NodeType {
   /// CopyFromReg - This node indicates that the input value is a virtual or
   /// physical register that is defined outside of the scope of this
   /// SelectionDAG.  The register is available from the RegisterSDNode object.
+  /// Not that CopyFromReg is considered as also freezing the value.
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arsenm wrote:

Note?

https://github.com/llvm/llvm-project/pull/85932