Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)

[oota-llvm.git] / include / llvm / CodeGen / CalcSpillWeights.h

diff --git a/include/llvm/CodeGen/CalcSpillWeights.h b/include/llvm/CodeGen/CalcSpillWeights.h
index 2fc03bd41de8fd5c24a39cc887e6c4877d4ee478..91fb0a9d7e77bdd39f01f3a9a982bc5ea2e3c818 100644 (file)
--- a/include/llvm/CodeGen/CalcSpillWeights.h
+++ b/include/llvm/CodeGen/CalcSpillWeights.h
@@ -11,29 +11,69 @@
 #ifndef LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 #define LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 
-#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/SlotIndexes.h"
 
 namespace llvm {
 
   class LiveInterval;
+  class LiveIntervals;
+  class MachineBlockFrequencyInfo;
+  class MachineLoopInfo;
 
-  /// CalculateSpillWeights - Compute spill weights for all virtual register
-  /// live intervals.
-  class CalculateSpillWeights : public MachineFunctionPass {
-  public:
-    static char ID;
+  /// \brief Normalize the spill weight of a live interval
+  ///
+  /// The spill weight of a live interval is computed as:
+  ///
+  ///   (sum(use freq) + sum(def freq)) / (K + size)
+  ///
+  /// @param UseDefFreq Expected number of executed use and def instructions
+  ///                   per function call. Derived from block frequencies.
+  /// @param Size       Size of live interval as returnexd by getSize()
+  /// @param NumInstr   Number of instructions using this live interval
+  ///
+  static inline float normalizeSpillWeight(float UseDefFreq, unsigned Size,
+                                           unsigned NumInstr) {
+    // The constant 25 instructions is added to avoid depending too much on
+    // accidental SlotIndex gaps for small intervals. The effect is that small
+    // intervals have a spill weight that is mostly proportional to the number
+    // of uses, while large intervals get a spill weight that is closer to a use
+    // density.
+    return UseDefFreq / (Size + 25*SlotIndex::InstrDist);
+  }
 
-    CalculateSpillWeights() : MachineFunctionPass(&ID) {}
+  /// \brief Calculate auxiliary information for a virtual register such as its
+  /// spill weight and allocation hint.
+  class VirtRegAuxInfo {
+  public:
+    typedef float (*NormalizingFn)(float, unsigned, unsigned);
 
-    virtual void getAnalysisUsage(AnalysisUsage &au) const;
+  private:
+    MachineFunction &MF;
+    LiveIntervals &LIS;
+    const MachineLoopInfo &Loops;
+    const MachineBlockFrequencyInfo &MBFI;
+    DenseMap<unsigned, float> Hint;
+    NormalizingFn normalize;
 
-    virtual bool runOnMachineFunction(MachineFunction &fn);    
+  public:
+    VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
+                   const MachineLoopInfo &loops,
+                   const MachineBlockFrequencyInfo &mbfi,
+                   NormalizingFn norm = normalizeSpillWeight)
+        : MF(mf), LIS(lis), Loops(loops), MBFI(mbfi), normalize(norm) {}
 
-  private:
-    /// Returns true if the given live interval is zero length.
-    bool isZeroLengthInterval(LiveInterval *li) const;
+    /// \brief (re)compute li's spill weight and allocation hint.
+    void calculateSpillWeightAndHint(LiveInterval &li);
   };
 
+  /// \brief Compute spill weights and allocation hints for all virtual register
+  /// live intervals.
+  void calculateSpillWeightsAndHints(LiveIntervals &LIS, MachineFunction &MF,
+                                     const MachineLoopInfo &MLI,
+                                     const MachineBlockFrequencyInfo &MBFI,
+                                     VirtRegAuxInfo::NormalizingFn norm =
+                                         normalizeSpillWeight);
 }
 
 #endif // LLVM_CODEGEN_CALCSPILLWEIGHTS_H