#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 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_;
- const MachineLoopInfo &loops_;
- DenseMap<unsigned, float> hint_;
+ MachineFunction &MF;
+ LiveIntervals &LIS;
+ const MachineLoopInfo &Loops;
+ DenseMap<unsigned, float> Hint;
public:
VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
const 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);
+ MF(mf), LIS(lis), Loops(loops) {}
/// CalculateWeightAndHint - (re)compute li's spill weight and allocation
/// hint.
public:
static char ID;
- CalculateSpillWeights() : MachineFunctionPass(ID) {}
+ CalculateSpillWeights() : MachineFunctionPass(ID) {
+ initializeCalculateSpillWeightsPass(*PassRegistry::getPassRegistry());
+ }
virtual void getAnalysisUsage(AnalysisUsage &au) const;