misched: rename ScheduleDAGILP to ScheduleDFS to prepare for other heuristics.

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

diff --git a/include/llvm/CodeGen/CalcSpillWeights.h b/include/llvm/CodeGen/CalcSpillWeights.h
index 99703a1c10a3323c9f01e0595a131fa071a4f1af..2f76a6cc5583d86713188b447525f8f4dab3f680 100644 (file)
--- a/include/llvm/CodeGen/CalcSpillWeights.h
+++ b/include/llvm/CodeGen/CalcSpillWeights.h
@@ -11,7 +11,7 @@
 #ifndef LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 #define LLVM_CODEGEN_CALCSPILLWEIGHTS_H
 
-#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/ADT/DenseMap.h"
 
 namespace llvm {
@@ -20,22 +20,34 @@ namespace llvm {
   class LiveIntervals;
   class MachineLoopInfo;
 
+  /// normalizeSpillWeight - 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()
+  ///
+  static inline float normalizeSpillWeight(float UseDefFreq, unsigned Size) {
+    // 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);
+  }
+
   /// VirtRegAuxInfo - Calculate auxiliary information for a virtual
   /// register such as its spill weight and allocation hint.
   class VirtRegAuxInfo {
-    MachineFunction &mf_;
-    LiveIntervals &lis_;
-    MachineLoopInfo &loops_;
-    DenseMap<unsigned, float> hint_;
+    MachineFunction &MF;
+    LiveIntervals &LIS;
+    const MachineLoopInfo &Loops;
+    DenseMap<unsigned, float> Hint;
   public:
     VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
-                   MachineLoopInfo &loops) :
-      mf_(mf), lis_(lis), loops_(loops) {}
-
-    /// CalculateRegClass - recompute the register class for li from its uses.
-    /// Since the register class can affect the allocation hint, this function
-    /// should be called before CalculateWeightAndHint if both are called.
-    void CalculateRegClass(LiveInterval &li);
+                   const MachineLoopInfo &loops) :
+      MF(mf), LIS(lis), Loops(loops) {}
 
     /// CalculateWeightAndHint - (re)compute li's spill weight and allocation
     /// hint.
@@ -48,7 +60,9 @@ namespace llvm {
   public:
     static char ID;
 
-    CalculateSpillWeights() : MachineFunctionPass(ID) {}
+    CalculateSpillWeights() : MachineFunctionPass(ID) {
+      initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
+    }
 
     virtual void getAnalysisUsage(AnalysisUsage &au) const;