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[MachineScheduler]Add support for store clustering

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Perform store clustering just like load clustering. This change add
StoreClusterMutation in machine-scheduler. To control StoreClusterMutation,
added enableClusterStores() in TargetInstrInfo.h. This is enabled only on
AArch64 for now.

This change also add support for unscaled stores which were not handled in
getMemOpBaseRegImmOfs().

llvm-svn: 266437
This commit is contained in:
Jun Bum Lim
2016-04-15 14:58:38 +00:00
parent 061d496c51
commit 4c5bd58ebe
10 changed files with 254 additions and 66 deletions
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95
llvm/lib/CodeGen/MachineScheduler.cpp
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@@ -71,8 +71,9 @@ static cl::opt<bool> EnableRegPressure("misched-regpressure", cl::Hidden,
static cl::opt<bool> EnableCyclicPath("misched-cyclicpath", cl::Hidden,
cl::desc("Enable cyclic critical path analysis."), cl::init(true));
static cl::opt<bool> EnableLoadCluster("misched-cluster", cl::Hidden,
cl::desc("Enable load clustering."), cl::init(true));
static cl::opt<bool> EnableMemOpCluster("misched-cluster", cl::Hidden,
cl::desc("Enable memop clustering."),
cl::init(true));
// Experimental heuristics
static cl::opt<bool> EnableMacroFusion("misched-fusion", cl::Hidden,
@@ -1351,64 +1352,80 @@ void ScheduleDAGMILive::scheduleMI(SUnit *SU, bool IsTopNode) {
}
//===----------------------------------------------------------------------===//
// LoadClusterMutation - DAG post-processing to cluster loads.
// BaseMemOpClusterMutation - DAG post-processing to cluster loads or stores.
//===----------------------------------------------------------------------===//
namespace {
/// \brief Post-process the DAG to create cluster edges between neighboring
/// loads.
class LoadClusterMutation : public ScheduleDAGMutation {
struct LoadInfo {
/// loads or between neighboring stores.
class BaseMemOpClusterMutation : public ScheduleDAGMutation {
struct MemOpInfo {
SUnit *SU;
unsigned BaseReg;
int64_t Offset;
LoadInfo(SUnit *su, unsigned reg, int64_t ofs)
: SU(su), BaseReg(reg), Offset(ofs) {}
MemOpInfo(SUnit *su, unsigned reg, int64_t ofs)
: SU(su), BaseReg(reg), Offset(ofs) {}
bool operator<(const LoadInfo &RHS) const {
bool operator<(const MemOpInfo&RHS) const {
return std::tie(BaseReg, Offset) < std::tie(RHS.BaseReg, RHS.Offset);
}
};
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
bool IsLoad;
public:
LoadClusterMutation(const TargetInstrInfo *tii,
const TargetRegisterInfo *tri)
: TII(tii), TRI(tri) {}
BaseMemOpClusterMutation(const TargetInstrInfo *tii,
const TargetRegisterInfo *tri, bool IsLoad)
: TII(tii), TRI(tri), IsLoad(IsLoad) {}
void apply(ScheduleDAGInstrs *DAGInstrs) override;
protected:
void clusterNeighboringLoads(ArrayRef<SUnit*> Loads, ScheduleDAGMI *DAG);
void clusterNeighboringMemOps(ArrayRef<SUnit *> MemOps, ScheduleDAGMI *DAG);
};
class StoreClusterMutation : public BaseMemOpClusterMutation {
public:
StoreClusterMutation(const TargetInstrInfo *tii,
const TargetRegisterInfo *tri)
: BaseMemOpClusterMutation(tii, tri, false) {}
};
class LoadClusterMutation : public BaseMemOpClusterMutation {
public:
LoadClusterMutation(const TargetInstrInfo *tii, const TargetRegisterInfo *tri)
: BaseMemOpClusterMutation(tii, tri, true) {}
};
} // anonymous
void LoadClusterMutation::clusterNeighboringLoads(ArrayRef<SUnit*> Loads,
ScheduleDAGMI *DAG) {
SmallVector<LoadClusterMutation::LoadInfo,32> LoadRecords;
for (unsigned Idx = 0, End = Loads.size(); Idx != End; ++Idx) {
SUnit *SU = Loads[Idx];
void BaseMemOpClusterMutation::clusterNeighboringMemOps(
ArrayRef<SUnit *> MemOps, ScheduleDAGMI *DAG) {
SmallVector<MemOpInfo, 32> MemOpRecords;
for (unsigned Idx = 0, End = MemOps.size(); Idx != End; ++Idx) {
SUnit *SU = MemOps[Idx];
unsigned BaseReg;
int64_t Offset;
if (TII->getMemOpBaseRegImmOfs(SU->getInstr(), BaseReg, Offset, TRI))
LoadRecords.push_back(LoadInfo(SU, BaseReg, Offset));
MemOpRecords.push_back(MemOpInfo(SU, BaseReg, Offset));
}
if (LoadRecords.size() < 2)
if (MemOpRecords.size() < 2)
return;
std::sort(LoadRecords.begin(), LoadRecords.end());
std::sort(MemOpRecords.begin(), MemOpRecords.end());
unsigned ClusterLength = 1;
for (unsigned Idx = 0, End = LoadRecords.size(); Idx < (End - 1); ++Idx) {
if (LoadRecords[Idx].BaseReg != LoadRecords[Idx+1].BaseReg) {
for (unsigned Idx = 0, End = MemOpRecords.size(); Idx < (End - 1); ++Idx) {
if (MemOpRecords[Idx].BaseReg != MemOpRecords[Idx+1].BaseReg) {
ClusterLength = 1;
continue;
}
SUnit *SUa = LoadRecords[Idx].SU;
SUnit *SUb = LoadRecords[Idx+1].SU;
if (TII->shouldClusterLoads(SUa->getInstr(), SUb->getInstr(), ClusterLength)
SUnit *SUa = MemOpRecords[Idx].SU;
SUnit *SUb = MemOpRecords[Idx+1].SU;
if (TII->shouldClusterMemOps(SUa->getInstr(), SUb->getInstr(), ClusterLength)
&& DAG->addEdge(SUb, SDep(SUa, SDep::Cluster))) {
DEBUG(dbgs() << "Cluster loads SU(" << SUa->NodeNum << ") - SU("
DEBUG(dbgs() << "Cluster ld/st SU(" << SUa->NodeNum << ") - SU("
<< SUb->NodeNum << ")\n");
// Copy successor edges from SUa to SUb. Interleaving computation
// dependent on SUa can prevent load combining due to register reuse.
@@ -1429,17 +1446,20 @@ void LoadClusterMutation::clusterNeighboringLoads(ArrayRef<SUnit*> Loads,
}
/// \brief Callback from DAG postProcessing to create cluster edges for loads.
void LoadClusterMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
void BaseMemOpClusterMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);
// Map DAG NodeNum to store chain ID.
DenseMap<unsigned, unsigned> StoreChainIDs;
// Map each store chain to a set of dependent loads.
// Map each store chain to a set of dependent MemOps.
SmallVector<SmallVector<SUnit*,4>, 32> StoreChainDependents;
for (unsigned Idx = 0, End = DAG->SUnits.size(); Idx != End; ++Idx) {
SUnit *SU = &DAG->SUnits[Idx];
if (!SU->getInstr()->mayLoad())
if ((IsLoad && !SU->getInstr()->mayLoad()) ||
(!IsLoad && !SU->getInstr()->mayStore()))
continue;
unsigned ChainPredID = DAG->SUnits.size();
for (SUnit::const_pred_iterator
PI = SU->Preds.begin(), PE = SU->Preds.end(); PI != PE; ++PI) {
@@ -1449,7 +1469,7 @@ void LoadClusterMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
}
}
// Check if this chain-like pred has been seen
// before. ChainPredID==MaxNodeID for loads at the top of the schedule.
// before. ChainPredID==MaxNodeID at the top of the schedule.
unsigned NumChains = StoreChainDependents.size();
std::pair<DenseMap<unsigned, unsigned>::iterator, bool> Result =
StoreChainIDs.insert(std::make_pair(ChainPredID, NumChains));
@@ -1457,9 +1477,10 @@ void LoadClusterMutation::apply(ScheduleDAGInstrs *DAGInstrs) {
StoreChainDependents.resize(NumChains + 1);
StoreChainDependents[Result.first->second].push_back(SU);
}
// Iterate over the store chains.
for (unsigned Idx = 0, End = StoreChainDependents.size(); Idx != End; ++Idx)
clusterNeighboringLoads(StoreChainDependents[Idx], DAG);
clusterNeighboringMemOps(StoreChainDependents[Idx], DAG);
}
//===----------------------------------------------------------------------===//
@@ -3054,8 +3075,12 @@ static ScheduleDAGInstrs *createGenericSchedLive(MachineSchedContext *C) {
// data and pass it to later mutations. Have a single mutation that gathers
// the interesting nodes in one pass.
DAG->addMutation(make_unique<CopyConstrain>(DAG->TII, DAG->TRI));
if (EnableLoadCluster && DAG->TII->enableClusterLoads())
DAG->addMutation(make_unique<LoadClusterMutation>(DAG->TII, DAG->TRI));
if (EnableMemOpCluster) {
if (DAG->TII->enableClusterLoads())
DAG->addMutation(make_unique<LoadClusterMutation>(DAG->TII, DAG->TRI));
if (DAG->TII->enableClusterStores())
DAG->addMutation(make_unique<StoreClusterMutation>(DAG->TII, DAG->TRI));
}
if (EnableMacroFusion)
DAG->addMutation(make_unique<MacroFusion>(*DAG->TII, *DAG->TRI));
return DAG;