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diff --git a/clang-r353983/include/llvm/CodeGen/LazyMachineBlockFrequencyInfo.h b/clang-r353983/include/llvm/CodeGen/LazyMachineBlockFrequencyInfo.h
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+++ b/clang-r353983/include/llvm/CodeGen/LazyMachineBlockFrequencyInfo.h
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+///===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- 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
+///
+///===---------------------------------------------------------------------===//
+/// \file
+/// This is an alternative analysis pass to MachineBlockFrequencyInfo.  The
+/// difference is that with this pass the block frequencies are not computed
+/// when the analysis pass is executed but rather when the BFI result is
+/// explicitly requested by the analysis client.
+///
+///===---------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
+#define LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
+
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
+#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+
+namespace llvm {
+/// This is an alternative analysis pass to MachineBlockFrequencyInfo.
+/// The difference is that with this pass, the block frequencies are not
+/// computed when the analysis pass is executed but rather when the BFI result
+/// is explicitly requested by the analysis client.
+///
+/// This works by checking querying if MBFI is available and otherwise
+/// generating MBFI on the fly.  In this case the passes required for (LI, DT)
+/// are also queried before being computed on the fly.
+///
+/// Note that it is expected that we wouldn't need this functionality for the
+/// new PM since with the new PM, analyses are executed on demand.
+
+class LazyMachineBlockFrequencyInfoPass : public MachineFunctionPass {
+private:
+  /// If generated on the fly this own the instance.
+  mutable std::unique_ptr<MachineBlockFrequencyInfo> OwnedMBFI;
+
+  /// If generated on the fly this own the instance.
+  mutable std::unique_ptr<MachineLoopInfo> OwnedMLI;
+
+  /// If generated on the fly this own the instance.
+  mutable std::unique_ptr<MachineDominatorTree> OwnedMDT;
+
+  /// The function.
+  MachineFunction *MF = nullptr;
+
+  /// Calculate MBFI and all other analyses that's not available and
+  /// required by BFI.
+  MachineBlockFrequencyInfo &calculateIfNotAvailable() const;
+
+public:
+  static char ID;
+
+  LazyMachineBlockFrequencyInfoPass();
+
+  /// Compute and return the block frequencies.
+  MachineBlockFrequencyInfo &getBFI() { return calculateIfNotAvailable(); }
+
+  /// Compute and return the block frequencies.
+  const MachineBlockFrequencyInfo &getBFI() const {
+    return calculateIfNotAvailable();
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+  bool runOnMachineFunction(MachineFunction &F) override;
+  void releaseMemory() override;
+  void print(raw_ostream &OS, const Module *M) const override;
+};
+}
+#endif