[llvm] [CodeGen][NewPM] Port SpillPlacement analysis to NPM (PR #116618)

[Matt Arsenault via llvm-commits]

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@@ -154,17 +157,51 @@ class SpillPlacement : public MachineFunctionPass {
     return BlockFrequencies[Number];
   }
 
+  bool invalidate(MachineFunction &MF, const PreservedAnalyses &PA,
+                  MachineFunctionAnalysisManager::Invalidator &Inv);
+
+  // Out of line definitions so unique_ptr<Node[]> doesn't need to be complete.
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arsenm wrote:

Don't really need to comment this 

https://github.com/llvm/llvm-project/pull/116618