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thirdparty/capstone/suite/synctools/tablegen/include/llvm/CodeGen/MachineBranchProbabilityInfo.h

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+//=- MachineBranchProbabilityInfo.h - Branch Probability Analysis -*- 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 pass is used to evaluate branch probabilities on machine basic blocks.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H
+#define LLVM_CODEGEN_MACHINEBRANCHPROBABILITYINFO_H
+
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/BranchProbability.h"
+#include <climits>
+#include <numeric>
+
+namespace llvm {
+
+class MachineBranchProbabilityInfo : public ImmutablePass {
+  virtual void anchor();
+
+  // Default weight value. Used when we don't have information about the edge.
+  // TODO: DEFAULT_WEIGHT makes sense during static predication, when none of
+  // the successors have a weight yet. But it doesn't make sense when providing
+  // weight to an edge that may have siblings with non-zero weights. This can
+  // be handled various ways, but it's probably fine for an edge with unknown
+  // weight to just "inherit" the non-zero weight of an adjacent successor.
+  static const uint32_t DEFAULT_WEIGHT = 16;
+
+public:
+  static char ID;
+
+  MachineBranchProbabilityInfo();
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesAll();
+  }
+
+  // Return edge probability.
+  BranchProbability getEdgeProbability(const MachineBasicBlock *Src,
+                                       const MachineBasicBlock *Dst) const;
+
+  // Same as above, but using a const_succ_iterator from Src. This is faster
+  // when the iterator is already available.
+  BranchProbability
+  getEdgeProbability(const MachineBasicBlock *Src,
+                     MachineBasicBlock::const_succ_iterator Dst) const;
+
+  // A 'Hot' edge is an edge which probability is >= 80%.
+  bool isEdgeHot(const MachineBasicBlock *Src,
+                 const MachineBasicBlock *Dst) const;
+
+  // Print value between 0 (0% probability) and 1 (100% probability),
+  // however the value is never equal to 0, and can be 1 only iff SRC block
+  // has only one successor.
+  raw_ostream &printEdgeProbability(raw_ostream &OS,
+                                    const MachineBasicBlock *Src,
+                                    const MachineBasicBlock *Dst) const;
+};
+
+}
+
+
+#endif