[llvm] InstructionSelect: Use GISelChangeObserver instead of MachineFunction::Delegate (PR #105725)

[Tobias Stadler via llvm-commits]

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@@ -36,6 +38,8 @@ class InstructionSelector : public GIMatchTableExecutor {
   const TargetPassConfig *TPC = nullptr;
 
   MachineOptimizationRemarkEmitter *MORE = nullptr;
+
+  GISelObserverWrapper *AllObservers = nullptr;
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tobias-stadler wrote:

Add `/// Note: InstructionSelect does not track changed instructions. changingInstr() and changedInstr() will never be called on these observers.`?

https://github.com/llvm/llvm-project/pull/105725