[llvm] [NewPM][Instrumentation] Support `MachineOptimizationRemarkEmitter` (PR #90563)

[Arthur Eubanks via llvm-commits]

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@@ -1329,6 +1342,51 @@ struct PreservedModuleHashAnalysis
 
 AnalysisKey PreservedModuleHashAnalysis::Key;
 
+struct MachineInstrCounterAnalysis
+    : public AnalysisInfoMixin<MachineInstrCounterAnalysis> {
+  static AnalysisKey Key;
+
+  struct Result {
+    bool invalidate(MachineFunction &MF, const PreservedAnalyses &,
+                    MachineFunctionAnalysisManager::Invalidator &) {
+      return false;
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aeubanks wrote:

if this is never invalidated, then isn't `CountBefore` going to be wrong after the first pass that changes the instruction count?

https://github.com/llvm/llvm-project/pull/90563