1 files changed, 25 insertions, 1 deletions
diff --git a/include/llvm/Support/BlockFrequency.h b/include/llvm/Support/BlockFrequency.h
index 839cf93712472..21879e7cbe415 100644
--- a/include/llvm/Support/BlockFrequency.h
+++ b/include/llvm/Support/BlockFrequency.h
@@ -25,20 +25,44 @@ class BranchProbability;
 class BlockFrequency {
 
   uint64_t Frequency;
-  static const int64_t ENTRY_FREQ = 1024;
+  static const int64_t ENTRY_FREQ = 1 << 14;
+
+  /// \brief Scale the given BlockFrequency by N/D. Return the remainder from
+  /// the division by D. Upon overflow, the routine will saturate and
+  /// additionally will return the remainder set to D.
+  uint32_t scale(uint32_t N, uint32_t D);
 
 public:
   BlockFrequency(uint64_t Freq = 0) : Frequency(Freq) { }
 
+  /// \brief Returns the frequency of the entry block of the function.
   static uint64_t getEntryFrequency() { return ENTRY_FREQ; }
+
+  /// \brief Returns the maximum possible frequency, the saturation value.
+  static uint64_t getMaxFrequency() { return -1ULL; }
+
+  /// \brief Returns the frequency as a fixpoint number scaled by the entry
+  /// frequency.
   uint64_t getFrequency() const { return Frequency; }
 
+  /// \brief Multiplies with a branch probability. The computation will never
+  /// overflow.
   BlockFrequency &operator*=(const BranchProbability &Prob);
   const BlockFrequency operator*(const BranchProbability &Prob) const;
 
+  /// \brief Divide by a non-zero branch probability using saturating
+  /// arithmetic.
+  BlockFrequency &operator/=(const BranchProbability &Prob);
+  BlockFrequency operator/(const BranchProbability &Prob) const;
+
+  /// \brief Adds another block frequency using saturating arithmetic.
   BlockFrequency &operator+=(const BlockFrequency &Freq);
   const BlockFrequency operator+(const BlockFrequency &Freq) const;
 
+  /// \brief Scale the given BlockFrequency by N/D. Return the remainder from
+  /// the division by D. Upon overflow, the routine will saturate.
+  uint32_t scale(const BranchProbability &Prob);
+
   bool operator<(const BlockFrequency &RHS) const {
     return Frequency < RHS.Frequency;
   }