[llvm] [CodeGen] Port selection dag isel to new pass manager (PR #83567)

[Arthur Eubanks via llvm-commits]

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@@ -229,6 +230,7 @@ class SelectionDAG {
   const TargetLibraryInfo *LibInfo = nullptr;
   const FunctionVarLocs *FnVarLocs = nullptr;
   MachineFunction *MF;
+  MachineFunctionAnalysisManager *MFAM = nullptr;
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aeubanks wrote:

`SDAGISelPass` is only used in `SIISelLowering.cpp`, I don't think we need this for now

https://github.com/llvm/llvm-project/pull/83567