//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "regalloc"
#include "Spiller.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LiveRangeEdit.h"
#include "llvm/CodeGen/LiveStackAnalysis.h"
#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
+#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
using namespace llvm;
+#define DEBUG_TYPE "regalloc"
+
STATISTIC(NumSpilledRanges, "Number of spilled live ranges");
STATISTIC(NumSnippets, "Number of spilled snippets");
STATISTIC(NumSpills, "Number of spills inserted");
SibValueInfo(unsigned Reg, VNInfo *VNI)
: AllDefsAreReloads(true), DefByOrigPHI(false), KillsSource(false),
- SpillReg(Reg), SpillVNI(VNI), SpillMBB(0), DefMI(0) {}
+ SpillReg(Reg), SpillVNI(VNI), SpillMBB(nullptr), DefMI(nullptr) {}
// Returns true when a def has been found.
bool hasDef() const { return DefByOrigPHI || DefMI; }
~InlineSpiller() {}
public:
- InlineSpiller(MachineFunctionPass &pass,
- MachineFunction &mf,
- VirtRegMap &vrm)
- : MF(mf),
- LIS(pass.getAnalysis<LiveIntervals>()),
- LSS(pass.getAnalysis<LiveStacks>()),
- AA(&pass.getAnalysis<AliasAnalysis>()),
- MDT(pass.getAnalysis<MachineDominatorTree>()),
- Loops(pass.getAnalysis<MachineLoopInfo>()),
- VRM(vrm),
- MFI(*mf.getFrameInfo()),
- MRI(mf.getRegInfo()),
- TII(*mf.getTarget().getInstrInfo()),
- TRI(*mf.getTarget().getRegisterInfo()),
- MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
+ InlineSpiller(MachineFunctionPass &pass, MachineFunction &mf, VirtRegMap &vrm)
+ : MF(mf), LIS(pass.getAnalysis<LiveIntervals>()),
+ LSS(pass.getAnalysis<LiveStacks>()),
+ AA(&pass.getAnalysis<AliasAnalysis>()),
+ MDT(pass.getAnalysis<MachineDominatorTree>()),
+ Loops(pass.getAnalysis<MachineLoopInfo>()), VRM(vrm),
+ MFI(*mf.getFrameInfo()), MRI(mf.getRegInfo()),
+ TII(*mf.getSubtarget().getInstrInfo()),
+ TRI(*mf.getSubtarget().getRegisterInfo()),
+ MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()) {}
void spill(LiveRangeEdit &) override;
bool isSibling(unsigned Reg);
MachineInstr *traceSiblingValue(unsigned, VNInfo*, VNInfo*);
- void propagateSiblingValue(SibValueMap::iterator, VNInfo *VNI = 0);
+ void propagateSiblingValue(SibValueMap::iterator, VNInfo *VNI = nullptr);
void analyzeSiblingValues();
bool hoistSpill(LiveInterval &SpillLI, MachineInstr *CopyMI);
bool coalesceStackAccess(MachineInstr *MI, unsigned Reg);
bool foldMemoryOperand(ArrayRef<std::pair<MachineInstr*, unsigned> >,
- MachineInstr *LoadMI = 0);
+ MachineInstr *LoadMI = nullptr);
void insertReload(unsigned VReg, SlotIndex, MachineBasicBlock::iterator MI);
void insertSpill(unsigned VReg, bool isKill, MachineBasicBlock::iterator MI);
if (SnipLI.getNumValNums() > 2 || !LIS.intervalIsInOneMBB(SnipLI))
return false;
- MachineInstr *UseMI = 0;
+ MachineInstr *UseMI = nullptr;
// Check that all uses satisfy our criteria.
for (MachineRegisterInfo::reg_instr_nodbg_iterator
do {
SVI = WorkList.pop_back_val();
TinyPtrVector<VNInfo*> *Deps = VNI ? &FirstDeps : &SVI->second.Deps;
- VNI = 0;
+ VNI = nullptr;
SibValueInfo &SV = SVI->second;
if (!SV.SpillMBB)
// Also hoist spills to blocks with smaller loop depth, but make sure
// that the new value dominates. Non-phi dependents are always
// dominated, phis need checking.
+
+ const BranchProbability MarginProb(4, 5); // 80%
+ // Hoist a spill to outer loop if there are multiple dependents (it
+ // can be beneficial if more than one dependents are hoisted) or
+ // if DepSV (the hoisting source) is hotter than SV (the hoisting
+ // destination) (we add a 80% margin to bias a little towards
+ // loop depth).
+ bool HoistCondition =
+ (MBFI.getBlockFreq(DepSV.SpillMBB) >=
+ (MBFI.getBlockFreq(SV.SpillMBB) * MarginProb)) ||
+ Deps->size() > 1;
+
if ((Loops.getLoopDepth(DepSV.SpillMBB) > SpillDepth) &&
+ HoistCondition &&
(!DepSVI->first->isPHIDef() ||
MDT.dominates(SV.SpillMBB, DepSV.SpillMBB))) {
Changed = true;
VNInfo *VNI = *VI;
if (VNI->isUnused())
continue;
- MachineInstr *DefMI = 0;
+ MachineInstr *DefMI = nullptr;
if (!VNI->isPHIDef()) {
DefMI = LIS.getInstructionFromIndex(VNI->def);
assert(DefMI && "No defining instruction");
// Share a stack slot among all descendants of Original.
Original = VRM.getOriginal(edit.getReg());
StackSlot = VRM.getStackSlot(Original);
- StackInt = 0;
+ StackInt = nullptr;
DEBUG(dbgs() << "Inline spilling "
<< MRI.getRegClass(edit.getReg())->getName()