//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "sched-instrs"
-#include "RegisterPressure.h"
#include "llvm/Operator.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
+#include "llvm/CodeGen/RegisterPressure.h"
#include "llvm/CodeGen/ScheduleDAGInstrs.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Target/TargetMachine.h"
: ScheduleDAG(mf), MLI(mli), MDT(mdt), MFI(mf.getFrameInfo()),
InstrItins(mf.getTarget().getInstrItineraryData()), LIS(lis),
IsPostRA(IsPostRAFlag), UnitLatencies(false), CanHandleTerminators(false),
- LoopRegs(MLI, MDT), FirstDbgValue(0) {
+ LoopRegs(MDT), FirstDbgValue(0) {
assert((IsPostRA || LIS) && "PreRA scheduling requires LiveIntervals");
DbgValues.clear();
assert(!(IsPostRA && MRI.getNumVirtRegs()) &&
unsigned SpecialAddressLatency = ST.getSpecialAddressLatency();
unsigned DataLatency = SU->Latency;
- for (const uint16_t *Alias = TRI->getOverlaps(MO.getReg()); *Alias; ++Alias) {
+ for (MCRegAliasIterator Alias(MO.getReg(), TRI, true);
+ Alias.isValid(); ++Alias) {
if (!Uses.contains(*Alias))
continue;
std::vector<SUnit*> &UseList = Uses[*Alias];
// Adjust the dependence latency using operand def/use
// information (if any), and then allow the target to
// perform its own adjustments.
- const SDep& dep = SDep(SU, SDep::Data, LDataLatency, *Alias);
+ SDep dep(SU, SDep::Data, LDataLatency, *Alias);
if (!UnitLatencies) {
- computeOperandLatency(SU, UseSU, const_cast<SDep &>(dep));
- ST.adjustSchedDependency(SU, UseSU, const_cast<SDep &>(dep));
+ unsigned Latency = computeOperandLatency(SU, UseSU, dep);
+ dep.setLatency(Latency);
+
+ ST.adjustSchedDependency(SU, UseSU, dep);
}
UseSU->addPred(dep);
}
// TODO: Using a latency of 1 here for output dependencies assumes
// there's no cost for reusing registers.
SDep::Kind Kind = MO.isUse() ? SDep::Anti : SDep::Output;
- for (const uint16_t *Alias = TRI->getOverlaps(MO.getReg()); *Alias; ++Alias) {
+ for (MCRegAliasIterator Alias(MO.getReg(), TRI, true);
+ Alias.isValid(); ++Alias) {
if (!Defs.contains(*Alias))
continue;
std::vector<SUnit *> &DefList = Defs[*Alias];
const MachineInstr *MI = SU->getInstr();
unsigned Reg = MI->getOperand(OperIdx).getReg();
- // SSA defs do not have output/anti dependencies.
+ // Singly defined vregs do not have output/anti dependencies.
// The current operand is a def, so we have at least one.
- if (llvm::next(MRI.def_begin(Reg)) == MRI.def_end())
+ // Check here if there are any others...
+ if (MRI.hasOneDef(Reg))
return;
// Add output dependence to the next nearest def of this vreg.
// Create a data dependence.
//
// TODO: Handle "special" address latencies cleanly.
- const SDep &dep = SDep(DefSU, SDep::Data, DefSU->Latency, Reg);
+ SDep dep(DefSU, SDep::Data, DefSU->Latency, Reg);
if (!UnitLatencies) {
// Adjust the dependence latency using operand def/use information, then
// allow the target to perform its own adjustments.
- computeOperandLatency(DefSU, SU, const_cast<SDep &>(dep));
+ unsigned Latency = computeOperandLatency(DefSU, SU, const_cast<SDep &>(dep));
+ dep.setLatency(Latency);
+
const TargetSubtargetInfo &ST = TM.getSubtarget<TargetSubtargetInfo>();
ST.adjustSchedDependency(DefSU, SU, const_cast<SDep &>(dep));
}
/// checks whether SU can be aliasing any node dominated
/// by it.
static void adjustChainDeps(AliasAnalysis *AA, const MachineFrameInfo *MFI,
- SUnit *SU, SUnit *ExitSU, std::set<SUnit *> &CheckList) {
+ SUnit *SU, SUnit *ExitSU, std::set<SUnit *> &CheckList,
+ unsigned LatencyToLoad) {
if (!SU)
return;
I != IE; ++I) {
if (SU == *I)
continue;
- if (MIsNeedChainEdge(AA, MFI, SU->getInstr(), (*I)->getInstr()))
- (*I)->addPred(SDep(SU, SDep::Order, /*Latency=*/0, /*Reg=*/0,
+ if (MIsNeedChainEdge(AA, MFI, SU->getInstr(), (*I)->getInstr())) {
+ unsigned Latency = ((*I)->getInstr()->mayLoad()) ? LatencyToLoad : 0;
+ (*I)->addPred(SDep(SU, SDep::Order, Latency, /*Reg=*/0,
/*isNormalMemory=*/true));
+ }
// Now go through all the chain successors and iterate from them.
// Keep track of visited nodes.
for (SUnit::const_succ_iterator J = (*I)->Succs.begin(),
// after stack slots are lowered to actual addresses.
// TODO: Use an AliasAnalysis and do real alias-analysis queries, and
// produce more precise dependence information.
-#define STORE_LOAD_LATENCY 1
- unsigned TrueMemOrderLatency = 0;
+ unsigned TrueMemOrderLatency = MI->mayStore() ? 1 : 0;
if (isGlobalMemoryObject(AA, MI)) {
// Be conservative with these and add dependencies on all memory
// references, even those that are known to not alias.
BarrierChain = SU;
// This is a barrier event that acts as a pivotal node in the DAG,
// so it is safe to clear list of exposed nodes.
- adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes);
+ adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes,
+ TrueMemOrderLatency);
RejectMemNodes.clear();
NonAliasMemDefs.clear();
NonAliasMemUses.clear();
// fall-through
new_alias_chain:
// Chain all possibly aliasing memory references though SU.
- if (AliasChain)
- addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes);
+ if (AliasChain) {
+ unsigned ChainLatency = 0;
+ if (AliasChain->getInstr()->mayLoad())
+ ChainLatency = TrueMemOrderLatency;
+ addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes,
+ ChainLatency);
+ }
AliasChain = SU;
for (unsigned k = 0, m = PendingLoads.size(); k != m; ++k)
addChainDependency(AA, MFI, SU, PendingLoads[k], RejectMemNodes,
addChainDependency(AA, MFI, SU, I->second[i], RejectMemNodes,
TrueMemOrderLatency);
}
- adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes);
+ adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes,
+ TrueMemOrderLatency);
PendingLoads.clear();
AliasMemDefs.clear();
AliasMemUses.clear();
} else if (MI->mayStore()) {
bool MayAlias = true;
- TrueMemOrderLatency = STORE_LOAD_LATENCY;
if (const Value *V = getUnderlyingObjectForInstr(MI, MFI, MayAlias)) {
// A store to a specific PseudoSourceValue. Add precise dependencies.
// Record the def in MemDefs, first adding a dep if there is
addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes);
// But we also should check dependent instructions for the
// SU in question.
- adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes);
+ adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes,
+ TrueMemOrderLatency);
}
// Add dependence on barrier chain, if needed.
// There is no point to check aliasing on barrier event. Even if
/*isArtificial=*/true));
} else if (MI->mayLoad()) {
bool MayAlias = true;
- TrueMemOrderLatency = 0;
if (MI->isInvariantLoad(AA)) {
// Invariant load, no chain dependencies needed!
} else {
MayAlias = true;
}
if (MayAlias)
- adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes);
+ adjustChainDeps(AA, MFI, SU, &ExitSU, RejectMemNodes, /*Latency=*/0);
// Add dependencies on alias and barrier chains, if needed.
if (MayAlias && AliasChain)
addChainDependency(AA, MFI, SU, AliasChain, RejectMemNodes);
}
void ScheduleDAGInstrs::computeLatency(SUnit *SU) {
- // Compute the latency for the node.
- if (!InstrItins || InstrItins->isEmpty()) {
+ // Compute the latency for the node. We only provide a default for missing
+ // itineraries. Empty itineraries still have latency properties.
+ if (!InstrItins) {
SU->Latency = 1;
// Simplistic target-independent heuristic: assume that loads take
}
}
-void ScheduleDAGInstrs::computeOperandLatency(SUnit *Def, SUnit *Use,
- SDep& dep) const {
- if (!InstrItins || InstrItins->isEmpty())
- return;
-
+unsigned ScheduleDAGInstrs::computeOperandLatency(SUnit *Def, SUnit *Use,
+ const SDep& dep,
+ bool FindMin) const {
// For a data dependency with a known register...
if ((dep.getKind() != SDep::Data) || (dep.getReg() == 0))
- return;
+ return 1;
- const unsigned Reg = dep.getReg();
-
- // ... find the definition of the register in the defining
- // instruction
- MachineInstr *DefMI = Def->getInstr();
- int DefIdx = DefMI->findRegisterDefOperandIdx(Reg);
- if (DefIdx != -1) {
- const MachineOperand &MO = DefMI->getOperand(DefIdx);
- if (MO.isReg() && MO.isImplicit() &&
- DefIdx >= (int)DefMI->getDesc().getNumOperands()) {
- // This is an implicit def, getOperandLatency() won't return the correct
- // latency. e.g.
- // %D6<def>, %D7<def> = VLD1q16 %R2<kill>, 0, ..., %Q3<imp-def>
- // %Q1<def> = VMULv8i16 %Q1<kill>, %Q3<kill>, ...
- // What we want is to compute latency between def of %D6/%D7 and use of
- // %Q3 instead.
- unsigned Op2 = DefMI->findRegisterDefOperandIdx(Reg, false, true, TRI);
- if (DefMI->getOperand(Op2).isReg())
- DefIdx = Op2;
- }
- MachineInstr *UseMI = Use->getInstr();
- // For all uses of the register, calculate the maxmimum latency
- int Latency = -1;
- if (UseMI) {
- for (unsigned i = 0, e = UseMI->getNumOperands(); i != e; ++i) {
- const MachineOperand &MO = UseMI->getOperand(i);
- if (!MO.isReg() || !MO.isUse())
- continue;
- unsigned MOReg = MO.getReg();
- if (MOReg != Reg)
- continue;
-
- int UseCycle = TII->getOperandLatency(InstrItins, DefMI, DefIdx,
- UseMI, i);
- Latency = std::max(Latency, UseCycle);
- }
- } else {
- // UseMI is null, then it must be a scheduling barrier.
- if (!InstrItins || InstrItins->isEmpty())
- return;
- unsigned DefClass = DefMI->getDesc().getSchedClass();
- Latency = InstrItins->getOperandCycle(DefClass, DefIdx);
- }
-
- // If we found a latency, then replace the existing dependence latency.
- if (Latency >= 0)
- dep.setLatency(Latency);
- }
+ return TII->computeOperandLatency(InstrItins, TRI, Def->getInstr(),
+ Use->getInstr(), dep.getReg(), FindMin);
}
void ScheduleDAGInstrs::dumpNode(const SUnit *SU) const {
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