[llvm] [CodeGen] Add MachineRegisterClassInfo analysis pass (PR #120690)

[Akshat Oke via llvm-commits]

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@@ -0,0 +1,57 @@
+//=- MachineRegisterClassInfo.h - Machine Register Class Info -----*- C++ -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This analysis calculates register class info via RegisterClassInfo.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_MACHINEREGISTERCLASSINFO_H
+#define LLVM_CODEGEN_MACHINEREGISTERCLASSINFO_H
+
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachinePassManager.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+#include "llvm/Pass.h"
+
+namespace llvm {
+
+class MachineRegisterClassAnalysis
+    : public AnalysisInfoMixin<MachineRegisterClassAnalysis> {
+  friend AnalysisInfoMixin<MachineRegisterClassAnalysis>;
+
+  static AnalysisKey Key;
+
+public:
+  using Result = RegisterClassInfo;
+
+  Result run(MachineFunction &, MachineFunctionAnalysisManager &);
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optimisan wrote:

If most passes preserve this result (seems like they do), `RegisterClassInfo` should implement `bool invalidate` with `return !preservedWhenStateless();` (like how `InlineAdvisorAnalysis::Result::invalidate` does)

https://github.com/llvm/llvm-project/pull/120690