/usr/include/llvm-6.0/llvm/CodeGen/CalcSpillWeights.h is in llvm-6.0-dev 1:6.0-1ubuntu2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 | //===- lib/CodeGen/CalcSpillWeights.h ---------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_CALCSPILLWEIGHTS_H
#define LLVM_CODEGEN_CALCSPILLWEIGHTS_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/SlotIndexes.h"
namespace llvm {
class LiveInterval;
class LiveIntervals;
class MachineBlockFrequencyInfo;
class MachineFunction;
class MachineLoopInfo;
class VirtRegMap;
/// \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);
}
/// \brief Calculate auxiliary information for a virtual register such as its
/// spill weight and allocation hint.
class VirtRegAuxInfo {
public:
using NormalizingFn = float (*)(float, unsigned, unsigned);
private:
MachineFunction &MF;
LiveIntervals &LIS;
VirtRegMap *VRM;
const MachineLoopInfo &Loops;
const MachineBlockFrequencyInfo &MBFI;
DenseMap<unsigned, float> Hint;
NormalizingFn normalize;
public:
VirtRegAuxInfo(MachineFunction &mf, LiveIntervals &lis,
VirtRegMap *vrm, const MachineLoopInfo &loops,
const MachineBlockFrequencyInfo &mbfi,
NormalizingFn norm = normalizeSpillWeight)
: MF(mf), LIS(lis), VRM(vrm), Loops(loops), MBFI(mbfi), normalize(norm) {}
/// \brief (re)compute li's spill weight and allocation hint.
void calculateSpillWeightAndHint(LiveInterval &li);
/// \brief Compute future expected spill weight of a split artifact of li
/// that will span between start and end slot indexes.
/// \param li The live interval to be split.
/// \param start The expected begining of the split artifact. Instructions
/// before start will not affect the weight.
/// \param end The expected end of the split artifact. Instructions
/// after end will not affect the weight.
/// \return The expected spill weight of the split artifact. Returns
/// negative weight for unspillable li.
float futureWeight(LiveInterval &li, SlotIndex start, SlotIndex end);
/// \brief Helper function for weight calculations.
/// (Re)compute li's spill weight and allocation hint, or, for non null
/// start and end - compute future expected spill weight of a split
/// artifact of li that will span between start and end slot indexes.
/// \param li The live interval for which to compute the weight.
/// \param start The expected begining of the split artifact. Instructions
/// before start will not affect the weight. Relevant for
/// weight calculation of future split artifact.
/// \param end The expected end of the split artifact. Instructions
/// after end will not affect the weight. Relevant for
/// weight calculation of future split artifact.
/// \return The spill weight. Returns negative weight for unspillable li.
float weightCalcHelper(LiveInterval &li, SlotIndex *start = nullptr,
SlotIndex *end = nullptr);
};
/// \brief Compute spill weights and allocation hints for all virtual register
/// live intervals.
void calculateSpillWeightsAndHints(LiveIntervals &LIS, MachineFunction &MF,
VirtRegMap *VRM,
const MachineLoopInfo &MLI,
const MachineBlockFrequencyInfo &MBFI,
VirtRegAuxInfo::NormalizingFn norm =
normalizeSpillWeight);
} // end namespace llvm
#endif // LLVM_CODEGEN_CALCSPILLWEIGHTS_H
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