//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "post-RA-sched"
+#include "llvm/CodeGen/Passes.h"
#include "AggressiveAntiDepBreaker.h"
+#include "AntiDepBreaker.h"
#include "CriticalAntiDepBreaker.h"
-#include "ExactHazardRecognizer.h"
-#include "SimpleHazardRecognizer.h"
-#include "ScheduleDAGInstrs.h"
-#include "llvm/CodeGen/Passes.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/CodeGen/LatencyPriorityQueue.h"
-#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+#include "llvm/CodeGen/ScheduleDAGInstrs.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
-#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Target/TargetLowering.h"
-#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetSubtarget.h"
+#include "llvm/CodeGen/SchedulerRegistry.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/Statistic.h"
-#include <map>
-#include <set>
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "post-RA-sched"
+
STATISTIC(NumNoops, "Number of noops inserted");
STATISTIC(NumStalls, "Number of pipeline stalls");
STATISTIC(NumFixedAnti, "Number of fixed anti-dependencies");
// Post-RA scheduling is enabled with
-// TargetSubtarget.enablePostRAScheduler(). This flag can be used to
+// TargetSubtargetInfo.enablePostRAScheduler(). This flag can be used to
// override the target.
static cl::opt<bool>
EnablePostRAScheduler("post-RA-scheduler",
cl::desc("Break post-RA scheduling anti-dependencies: "
"\"critical\", \"all\", or \"none\""),
cl::init("none"), cl::Hidden);
-static cl::opt<bool>
-EnablePostRAHazardAvoidance("avoid-hazards",
- cl::desc("Enable exact hazard avoidance"),
- cl::init(true), cl::Hidden);
// If DebugDiv > 0 then only schedule MBB with (ID % DebugDiv) == DebugMod
static cl::opt<int>
cl::desc("Debug control MBBs that are scheduled"),
cl::init(0), cl::Hidden);
+AntiDepBreaker::~AntiDepBreaker() { }
+
namespace {
class PostRAScheduler : public MachineFunctionPass {
- AliasAnalysis *AA;
- CodeGenOpt::Level OptLevel;
+ const TargetInstrInfo *TII;
+ RegisterClassInfo RegClassInfo;
public:
static char ID;
- PostRAScheduler(CodeGenOpt::Level ol) :
- MachineFunctionPass(&ID), OptLevel(ol) {}
+ PostRAScheduler() : MachineFunctionPass(ID) {}
- void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<AliasAnalysis>();
+ AU.addRequired<TargetPassConfig>();
AU.addRequired<MachineDominatorTree>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
- const char *getPassName() const {
- return "Post RA top-down list latency scheduler";
- }
-
- bool runOnMachineFunction(MachineFunction &Fn);
+ bool runOnMachineFunction(MachineFunction &Fn) override;
+
+ bool enablePostRAScheduler(
+ const TargetSubtargetInfo &ST, CodeGenOpt::Level OptLevel,
+ TargetSubtargetInfo::AntiDepBreakMode &Mode,
+ TargetSubtargetInfo::RegClassVector &CriticalPathRCs) const;
};
char PostRAScheduler::ID = 0;
/// AvailableQueue - The priority queue to use for the available SUnits.
///
LatencyPriorityQueue AvailableQueue;
-
+
/// PendingQueue - This contains all of the instructions whose operands have
/// been issued, but their results are not ready yet (due to the latency of
/// the operation). Once the operands becomes available, the instruction is
/// added to the AvailableQueue.
std::vector<SUnit*> PendingQueue;
- /// Topo - A topological ordering for SUnits.
- ScheduleDAGTopologicalSort Topo;
-
/// HazardRec - The hazard recognizer to use.
ScheduleHazardRecognizer *HazardRec;
/// AA - AliasAnalysis for making memory reference queries.
AliasAnalysis *AA;
- /// KillIndices - The index of the most recent kill (proceding bottom-up),
- /// or ~0u if the register is not live.
- unsigned KillIndices[TargetRegisterInfo::FirstVirtualRegister];
+ /// The schedule. Null SUnit*'s represent noop instructions.
+ std::vector<SUnit*> Sequence;
+
+ /// The index in BB of RegionEnd.
+ ///
+ /// This is the instruction number from the top of the current block, not
+ /// the SlotIndex. It is only used by the AntiDepBreaker.
+ unsigned EndIndex;
public:
- SchedulePostRATDList(MachineFunction &MF,
- const MachineLoopInfo &MLI,
- const MachineDominatorTree &MDT,
- ScheduleHazardRecognizer *HR,
- AntiDepBreaker *ADB,
- AliasAnalysis *aa)
- : ScheduleDAGInstrs(MF, MLI, MDT), Topo(SUnits),
- HazardRec(HR), AntiDepBreak(ADB), AA(aa) {}
-
- ~SchedulePostRATDList() {
- }
+ SchedulePostRATDList(
+ MachineFunction &MF, MachineLoopInfo &MLI, AliasAnalysis *AA,
+ const RegisterClassInfo &,
+ TargetSubtargetInfo::AntiDepBreakMode AntiDepMode,
+ SmallVectorImpl<const TargetRegisterClass *> &CriticalPathRCs);
+
+ ~SchedulePostRATDList();
- /// StartBlock - Initialize register live-range state for scheduling in
+ /// startBlock - Initialize register live-range state for scheduling in
/// this block.
///
- void StartBlock(MachineBasicBlock *BB);
+ void startBlock(MachineBasicBlock *BB) override;
+
+ // Set the index of RegionEnd within the current BB.
+ void setEndIndex(unsigned EndIdx) { EndIndex = EndIdx; }
+
+ /// Initialize the scheduler state for the next scheduling region.
+ void enterRegion(MachineBasicBlock *bb,
+ MachineBasicBlock::iterator begin,
+ MachineBasicBlock::iterator end,
+ unsigned regioninstrs) override;
+
+ /// Notify that the scheduler has finished scheduling the current region.
+ void exitRegion() override;
/// Schedule - Schedule the instruction range using list scheduling.
///
- void Schedule();
-
+ void schedule() override;
+
+ void EmitSchedule();
+
/// Observe - Update liveness information to account for the current
/// instruction, which will not be scheduled.
///
void Observe(MachineInstr *MI, unsigned Count);
- /// FinishBlock - Clean up register live-range state.
- ///
- void FinishBlock();
-
- /// FixupKills - Fix register kill flags that have been made
- /// invalid due to scheduling
+ /// finishBlock - Clean up register live-range state.
///
- void FixupKills(MachineBasicBlock *MBB);
+ void finishBlock() override;
private:
void ReleaseSucc(SUnit *SU, SDep *SuccEdge);
void ReleaseSuccessors(SUnit *SU);
void ScheduleNodeTopDown(SUnit *SU, unsigned CurCycle);
void ListScheduleTopDown();
- void StartBlockForKills(MachineBasicBlock *BB);
-
- // ToggleKillFlag - Toggle a register operand kill flag. Other
- // adjustments may be made to the instruction if necessary. Return
- // true if the operand has been deleted, false if not.
- bool ToggleKillFlag(MachineInstr *MI, MachineOperand &MO);
+
+ void dumpSchedule() const;
+ void emitNoop(unsigned CurCycle);
};
}
-/// isSchedulingBoundary - Test if the given instruction should be
-/// considered a scheduling boundary. This primarily includes labels
-/// and terminators.
-///
-static bool isSchedulingBoundary(const MachineInstr *MI,
- const MachineFunction &MF) {
- // Terminators and labels can't be scheduled around.
- if (MI->getDesc().isTerminator() || MI->isLabel())
- return true;
-
- // Don't attempt to schedule around any instruction that modifies
- // a stack-oriented pointer, as it's unlikely to be profitable. This
- // saves compile time, because it doesn't require every single
- // stack slot reference to depend on the instruction that does the
- // modification.
- const TargetLowering &TLI = *MF.getTarget().getTargetLowering();
- if (MI->modifiesRegister(TLI.getStackPointerRegisterToSaveRestore()))
- return true;
-
- return false;
+char &llvm::PostRASchedulerID = PostRAScheduler::ID;
+
+INITIALIZE_PASS(PostRAScheduler, "post-RA-sched",
+ "Post RA top-down list latency scheduler", false, false)
+
+SchedulePostRATDList::SchedulePostRATDList(
+ MachineFunction &MF, MachineLoopInfo &MLI, AliasAnalysis *AA,
+ const RegisterClassInfo &RCI,
+ TargetSubtargetInfo::AntiDepBreakMode AntiDepMode,
+ SmallVectorImpl<const TargetRegisterClass *> &CriticalPathRCs)
+ : ScheduleDAGInstrs(MF, &MLI, /*IsPostRA=*/true), AA(AA), EndIndex(0) {
+
+ const TargetMachine &TM = MF.getTarget();
+ const InstrItineraryData *InstrItins =
+ TM.getSubtargetImpl()->getInstrItineraryData();
+ HazardRec =
+ TM.getSubtargetImpl()->getInstrInfo()->CreateTargetPostRAHazardRecognizer(
+ InstrItins, this);
+
+ assert((AntiDepMode == TargetSubtargetInfo::ANTIDEP_NONE ||
+ MRI.tracksLiveness()) &&
+ "Live-ins must be accurate for anti-dependency breaking");
+ AntiDepBreak =
+ ((AntiDepMode == TargetSubtargetInfo::ANTIDEP_ALL) ?
+ (AntiDepBreaker *)new AggressiveAntiDepBreaker(MF, RCI, CriticalPathRCs) :
+ ((AntiDepMode == TargetSubtargetInfo::ANTIDEP_CRITICAL) ?
+ (AntiDepBreaker *)new CriticalAntiDepBreaker(MF, RCI) : nullptr));
+}
+
+SchedulePostRATDList::~SchedulePostRATDList() {
+ delete HazardRec;
+ delete AntiDepBreak;
+}
+
+/// Initialize state associated with the next scheduling region.
+void SchedulePostRATDList::enterRegion(MachineBasicBlock *bb,
+ MachineBasicBlock::iterator begin,
+ MachineBasicBlock::iterator end,
+ unsigned regioninstrs) {
+ ScheduleDAGInstrs::enterRegion(bb, begin, end, regioninstrs);
+ Sequence.clear();
+}
+
+/// Print the schedule before exiting the region.
+void SchedulePostRATDList::exitRegion() {
+ DEBUG({
+ dbgs() << "*** Final schedule ***\n";
+ dumpSchedule();
+ dbgs() << '\n';
+ });
+ ScheduleDAGInstrs::exitRegion();
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+/// dumpSchedule - dump the scheduled Sequence.
+void SchedulePostRATDList::dumpSchedule() const {
+ for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+ if (SUnit *SU = Sequence[i])
+ SU->dump(this);
+ else
+ dbgs() << "**** NOOP ****\n";
+ }
+}
+#endif
+
+bool PostRAScheduler::enablePostRAScheduler(
+ const TargetSubtargetInfo &ST,
+ CodeGenOpt::Level OptLevel,
+ TargetSubtargetInfo::AntiDepBreakMode &Mode,
+ TargetSubtargetInfo::RegClassVector &CriticalPathRCs) const {
+ Mode = ST.getAntiDepBreakMode();
+ ST.getCriticalPathRCs(CriticalPathRCs);
+ return ST.enablePostMachineScheduler() &&
+ OptLevel >= ST.getOptLevelToEnablePostRAScheduler();
}
bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
- AA = &getAnalysis<AliasAnalysis>();
+ if (skipOptnoneFunction(*Fn.getFunction()))
+ return false;
+
+ TII = Fn.getSubtarget().getInstrInfo();
+ MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>();
+ AliasAnalysis *AA = &getAnalysis<AliasAnalysis>();
+ TargetPassConfig *PassConfig = &getAnalysis<TargetPassConfig>();
+
+ RegClassInfo.runOnMachineFunction(Fn);
// Check for explicit enable/disable of post-ra scheduling.
- TargetSubtarget::AntiDepBreakMode AntiDepMode = TargetSubtarget::ANTIDEP_NONE;
+ TargetSubtargetInfo::AntiDepBreakMode AntiDepMode =
+ TargetSubtargetInfo::ANTIDEP_NONE;
+ SmallVector<const TargetRegisterClass*, 4> CriticalPathRCs;
if (EnablePostRAScheduler.getPosition() > 0) {
if (!EnablePostRAScheduler)
return false;
} else {
// Check that post-RA scheduling is enabled for this target.
- const TargetSubtarget &ST = Fn.getTarget().getSubtarget<TargetSubtarget>();
- if (!ST.enablePostRAScheduler(OptLevel, AntiDepMode))
+ // This may upgrade the AntiDepMode.
+ const TargetSubtargetInfo &ST =
+ Fn.getTarget().getSubtarget<TargetSubtargetInfo>();
+ if (!enablePostRAScheduler(ST, PassConfig->getOptLevel(),
+ AntiDepMode, CriticalPathRCs))
return false;
}
// Check for antidep breaking override...
if (EnableAntiDepBreaking.getPosition() > 0) {
- AntiDepMode = (EnableAntiDepBreaking == "all") ? TargetSubtarget::ANTIDEP_ALL :
- (EnableAntiDepBreaking == "critical") ? TargetSubtarget::ANTIDEP_CRITICAL :
- TargetSubtarget::ANTIDEP_NONE;
+ AntiDepMode = (EnableAntiDepBreaking == "all")
+ ? TargetSubtargetInfo::ANTIDEP_ALL
+ : ((EnableAntiDepBreaking == "critical")
+ ? TargetSubtargetInfo::ANTIDEP_CRITICAL
+ : TargetSubtargetInfo::ANTIDEP_NONE);
}
- DEBUG(errs() << "PostRAScheduler\n");
+ DEBUG(dbgs() << "PostRAScheduler\n");
- const MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>();
- const MachineDominatorTree &MDT = getAnalysis<MachineDominatorTree>();
- const InstrItineraryData &InstrItins = Fn.getTarget().getInstrItineraryData();
- ScheduleHazardRecognizer *HR = EnablePostRAHazardAvoidance ?
- (ScheduleHazardRecognizer *)new ExactHazardRecognizer(InstrItins) :
- (ScheduleHazardRecognizer *)new SimpleHazardRecognizer();
- AntiDepBreaker *ADB =
- ((AntiDepMode == TargetSubtarget::ANTIDEP_ALL) ?
- (AntiDepBreaker *)new AggressiveAntiDepBreaker(Fn) :
- ((AntiDepMode == TargetSubtarget::ANTIDEP_CRITICAL) ?
- (AntiDepBreaker *)new CriticalAntiDepBreaker(Fn) : NULL));
-
- SchedulePostRATDList Scheduler(Fn, MLI, MDT, HR, ADB, AA);
+ SchedulePostRATDList Scheduler(Fn, MLI, AA, RegClassInfo, AntiDepMode,
+ CriticalPathRCs);
// Loop over all of the basic blocks
for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
static int bbcnt = 0;
if (bbcnt++ % DebugDiv != DebugMod)
continue;
- errs() << "*** DEBUG scheduling " << Fn.getFunction()->getNameStr() <<
- ":MBB ID#" << MBB->getNumber() << " ***\n";
+ dbgs() << "*** DEBUG scheduling " << Fn.getName()
+ << ":BB#" << MBB->getNumber() << " ***\n";
}
#endif
// Initialize register live-range state for scheduling in this block.
- Scheduler.StartBlock(MBB);
+ Scheduler.startBlock(MBB);
// Schedule each sequence of instructions not interrupted by a label
// or anything else that effectively needs to shut down scheduling.
MachineBasicBlock::iterator Current = MBB->end();
unsigned Count = MBB->size(), CurrentCount = Count;
for (MachineBasicBlock::iterator I = Current; I != MBB->begin(); ) {
- MachineInstr *MI = prior(I);
- if (isSchedulingBoundary(MI, Fn)) {
- Scheduler.Run(MBB, I, Current, CurrentCount);
- Scheduler.EmitSchedule(0);
+ MachineInstr *MI = std::prev(I);
+ --Count;
+ // Calls are not scheduling boundaries before register allocation, but
+ // post-ra we don't gain anything by scheduling across calls since we
+ // don't need to worry about register pressure.
+ if (MI->isCall() || TII->isSchedulingBoundary(MI, MBB, Fn)) {
+ Scheduler.enterRegion(MBB, I, Current, CurrentCount - Count);
+ Scheduler.setEndIndex(CurrentCount);
+ Scheduler.schedule();
+ Scheduler.exitRegion();
+ Scheduler.EmitSchedule();
Current = MI;
- CurrentCount = Count - 1;
+ CurrentCount = Count;
Scheduler.Observe(MI, CurrentCount);
}
I = MI;
- --Count;
+ if (MI->isBundle())
+ Count -= MI->getBundleSize();
}
assert(Count == 0 && "Instruction count mismatch!");
assert((MBB->begin() == Current || CurrentCount != 0) &&
"Instruction count mismatch!");
- Scheduler.Run(MBB, MBB->begin(), Current, CurrentCount);
- Scheduler.EmitSchedule(0);
+ Scheduler.enterRegion(MBB, MBB->begin(), Current, CurrentCount);
+ Scheduler.setEndIndex(CurrentCount);
+ Scheduler.schedule();
+ Scheduler.exitRegion();
+ Scheduler.EmitSchedule();
// Clean up register live-range state.
- Scheduler.FinishBlock();
+ Scheduler.finishBlock();
// Update register kills
- Scheduler.FixupKills(MBB);
+ Scheduler.fixupKills(MBB);
}
- delete HR;
- delete ADB;
-
return true;
}
-
+
/// StartBlock - Initialize register live-range state for scheduling in
/// this block.
///
-void SchedulePostRATDList::StartBlock(MachineBasicBlock *BB) {
+void SchedulePostRATDList::startBlock(MachineBasicBlock *BB) {
// Call the superclass.
- ScheduleDAGInstrs::StartBlock(BB);
+ ScheduleDAGInstrs::startBlock(BB);
// Reset the hazard recognizer and anti-dep breaker.
HazardRec->Reset();
- if (AntiDepBreak != NULL)
+ if (AntiDepBreak)
AntiDepBreak->StartBlock(BB);
}
/// Schedule - Schedule the instruction range using list scheduling.
///
-void SchedulePostRATDList::Schedule() {
- DEBUG(errs() << "********** List Scheduling **********\n");
-
+void SchedulePostRATDList::schedule() {
// Build the scheduling graph.
- BuildSchedGraph(AA);
+ buildSchedGraph(AA);
+
+ if (AntiDepBreak) {
+ unsigned Broken =
+ AntiDepBreak->BreakAntiDependencies(SUnits, RegionBegin, RegionEnd,
+ EndIndex, DbgValues);
- if (AntiDepBreak != NULL) {
- unsigned Broken =
- AntiDepBreak->BreakAntiDependencies(SUnits, Begin, InsertPos,
- InsertPosIndex);
- if (Broken > 0) {
+ if (Broken != 0) {
// We made changes. Update the dependency graph.
// Theoretically we could update the graph in place:
// When a live range is changed to use a different register, remove
// the def's anti-dependence *and* output-dependence edges due to
// that register, and add new anti-dependence and output-dependence
// edges based on the next live range of the register.
- SUnits.clear();
- EntrySU = SUnit();
- ExitSU = SUnit();
- BuildSchedGraph(AA);
+ ScheduleDAG::clearDAG();
+ buildSchedGraph(AA);
NumFixedAnti += Broken;
}
}
+ DEBUG(dbgs() << "********** List Scheduling **********\n");
DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su)
SUnits[su].dumpAll(this));
AvailableQueue.initNodes(SUnits);
-
ListScheduleTopDown();
-
AvailableQueue.releaseState();
}
/// instruction, which will not be scheduled.
///
void SchedulePostRATDList::Observe(MachineInstr *MI, unsigned Count) {
- if (AntiDepBreak != NULL)
- AntiDepBreak->Observe(MI, Count, InsertPosIndex);
+ if (AntiDepBreak)
+ AntiDepBreak->Observe(MI, Count, EndIndex);
}
/// FinishBlock - Clean up register live-range state.
///
-void SchedulePostRATDList::FinishBlock() {
- if (AntiDepBreak != NULL)
+void SchedulePostRATDList::finishBlock() {
+ if (AntiDepBreak)
AntiDepBreak->FinishBlock();
// Call the superclass.
- ScheduleDAGInstrs::FinishBlock();
-}
-
-/// StartBlockForKills - Initialize register live-range state for updating kills
-///
-void SchedulePostRATDList::StartBlockForKills(MachineBasicBlock *BB) {
- // Initialize the indices to indicate that no registers are live.
- std::fill(KillIndices, array_endof(KillIndices), ~0u);
-
- // Determine the live-out physregs for this block.
- if (!BB->empty() && BB->back().getDesc().isReturn()) {
- // In a return block, examine the function live-out regs.
- for (MachineRegisterInfo::liveout_iterator I = MRI.liveout_begin(),
- E = MRI.liveout_end(); I != E; ++I) {
- unsigned Reg = *I;
- KillIndices[Reg] = BB->size();
- // Repeat, for all subregs.
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- KillIndices[*Subreg] = BB->size();
- }
- }
- }
- else {
- // In a non-return block, examine the live-in regs of all successors.
- for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
- SE = BB->succ_end(); SI != SE; ++SI) {
- for (MachineBasicBlock::livein_iterator I = (*SI)->livein_begin(),
- E = (*SI)->livein_end(); I != E; ++I) {
- unsigned Reg = *I;
- KillIndices[Reg] = BB->size();
- // Repeat, for all subregs.
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- KillIndices[*Subreg] = BB->size();
- }
- }
- }
- }
-}
-
-bool SchedulePostRATDList::ToggleKillFlag(MachineInstr *MI,
- MachineOperand &MO) {
- // Setting kill flag...
- if (!MO.isKill()) {
- MO.setIsKill(true);
- return false;
- }
-
- // If MO itself is live, clear the kill flag...
- if (KillIndices[MO.getReg()] != ~0u) {
- MO.setIsKill(false);
- return false;
- }
-
- // If any subreg of MO is live, then create an imp-def for that
- // subreg and keep MO marked as killed.
- MO.setIsKill(false);
- bool AllDead = true;
- const unsigned SuperReg = MO.getReg();
- for (const unsigned *Subreg = TRI->getSubRegisters(SuperReg);
- *Subreg; ++Subreg) {
- if (KillIndices[*Subreg] != ~0u) {
- MI->addOperand(MachineOperand::CreateReg(*Subreg,
- true /*IsDef*/,
- true /*IsImp*/,
- false /*IsKill*/,
- false /*IsDead*/));
- AllDead = false;
- }
- }
-
- if(AllDead)
- MO.setIsKill(true);
- return false;
-}
-
-/// FixupKills - Fix the register kill flags, they may have been made
-/// incorrect by instruction reordering.
-///
-void SchedulePostRATDList::FixupKills(MachineBasicBlock *MBB) {
- DEBUG(errs() << "Fixup kills for BB ID#" << MBB->getNumber() << '\n');
-
- std::set<unsigned> killedRegs;
- BitVector ReservedRegs = TRI->getReservedRegs(MF);
-
- StartBlockForKills(MBB);
-
- // Examine block from end to start...
- unsigned Count = MBB->size();
- for (MachineBasicBlock::iterator I = MBB->end(), E = MBB->begin();
- I != E; --Count) {
- MachineInstr *MI = --I;
-
- // Update liveness. Registers that are defed but not used in this
- // instruction are now dead. Mark register and all subregs as they
- // are completely defined.
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg()) continue;
- unsigned Reg = MO.getReg();
- if (Reg == 0) continue;
- if (!MO.isDef()) continue;
- // Ignore two-addr defs.
- if (MI->isRegTiedToUseOperand(i)) continue;
-
- KillIndices[Reg] = ~0u;
-
- // Repeat for all subregs.
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- KillIndices[*Subreg] = ~0u;
- }
- }
-
- // Examine all used registers and set/clear kill flag. When a
- // register is used multiple times we only set the kill flag on
- // the first use.
- killedRegs.clear();
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isUse()) continue;
- unsigned Reg = MO.getReg();
- if ((Reg == 0) || ReservedRegs.test(Reg)) continue;
-
- bool kill = false;
- if (killedRegs.find(Reg) == killedRegs.end()) {
- kill = true;
- // A register is not killed if any subregs are live...
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- if (KillIndices[*Subreg] != ~0u) {
- kill = false;
- break;
- }
- }
-
- // If subreg is not live, then register is killed if it became
- // live in this instruction
- if (kill)
- kill = (KillIndices[Reg] == ~0u);
- }
-
- if (MO.isKill() != kill) {
- bool removed = ToggleKillFlag(MI, MO);
- if (removed) {
- DEBUG(errs() << "Fixed <removed> in ");
- } else {
- DEBUG(errs() << "Fixed " << MO << " in ");
- }
- DEBUG(MI->dump());
- }
-
- killedRegs.insert(Reg);
- }
-
- // Mark any used register (that is not using undef) and subregs as
- // now live...
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (!MO.isReg() || !MO.isUse() || MO.isUndef()) continue;
- unsigned Reg = MO.getReg();
- if ((Reg == 0) || ReservedRegs.test(Reg)) continue;
-
- KillIndices[Reg] = Count;
-
- for (const unsigned *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- KillIndices[*Subreg] = Count;
- }
- }
- }
+ ScheduleDAGInstrs::finishBlock();
}
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
/// ReleaseSucc - Decrement the NumPredsLeft count of a successor. Add it to
-/// the PendingQueue if the count reaches zero. Also update its cycle bound.
+/// the PendingQueue if the count reaches zero.
void SchedulePostRATDList::ReleaseSucc(SUnit *SU, SDep *SuccEdge) {
SUnit *SuccSU = SuccEdge->getSUnit();
+ if (SuccEdge->isWeak()) {
+ --SuccSU->WeakPredsLeft;
+ return;
+ }
#ifndef NDEBUG
if (SuccSU->NumPredsLeft == 0) {
- errs() << "*** Scheduling failed! ***\n";
+ dbgs() << "*** Scheduling failed! ***\n";
SuccSU->dump(this);
- errs() << " has been released too many times!\n";
- llvm_unreachable(0);
+ dbgs() << " has been released too many times!\n";
+ llvm_unreachable(nullptr);
}
#endif
--SuccSU->NumPredsLeft;
- // Compute how many cycles it will be before this actually becomes
- // available. This is the max of the start time of all predecessors plus
- // their latencies.
- SuccSU->setDepthToAtLeast(SU->getDepth() + SuccEdge->getLatency());
-
+ // Standard scheduler algorithms will recompute the depth of the successor
+ // here as such:
+ // SuccSU->setDepthToAtLeast(SU->getDepth() + SuccEdge->getLatency());
+ //
+ // However, we lazily compute node depth instead. Note that
+ // ScheduleNodeTopDown has already updated the depth of this node which causes
+ // all descendents to be marked dirty. Setting the successor depth explicitly
+ // here would cause depth to be recomputed for all its ancestors. If the
+ // successor is not yet ready (because of a transitively redundant edge) then
+ // this causes depth computation to be quadratic in the size of the DAG.
+
// If all the node's predecessors are scheduled, this node is ready
// to be scheduled. Ignore the special ExitSU node.
if (SuccSU->NumPredsLeft == 0 && SuccSU != &ExitSU)
/// ReleaseSuccessors - Call ReleaseSucc on each of SU's successors.
void SchedulePostRATDList::ReleaseSuccessors(SUnit *SU) {
for (SUnit::succ_iterator I = SU->Succs.begin(), E = SU->Succs.end();
- I != E; ++I)
+ I != E; ++I) {
ReleaseSucc(SU, &*I);
+ }
}
/// ScheduleNodeTopDown - Add the node to the schedule. Decrement the pending
/// count of its successors. If a successor pending count is zero, add it to
/// the Available queue.
void SchedulePostRATDList::ScheduleNodeTopDown(SUnit *SU, unsigned CurCycle) {
- DEBUG(errs() << "*** Scheduling [" << CurCycle << "]: ");
+ DEBUG(dbgs() << "*** Scheduling [" << CurCycle << "]: ");
DEBUG(SU->dump(this));
-
+
Sequence.push_back(SU);
- assert(CurCycle >= SU->getDepth() && "Node scheduled above its depth!");
+ assert(CurCycle >= SU->getDepth() &&
+ "Node scheduled above its depth!");
SU->setDepthToAtLeast(CurCycle);
ReleaseSuccessors(SU);
SU->isScheduled = true;
- AvailableQueue.ScheduledNode(SU);
+ AvailableQueue.scheduledNode(SU);
+}
+
+/// emitNoop - Add a noop to the current instruction sequence.
+void SchedulePostRATDList::emitNoop(unsigned CurCycle) {
+ DEBUG(dbgs() << "*** Emitting noop in cycle " << CurCycle << '\n');
+ HazardRec->EmitNoop();
+ Sequence.push_back(nullptr); // NULL here means noop
+ ++NumNoops;
}
/// ListScheduleTopDown - The main loop of list scheduling for top-down
void SchedulePostRATDList::ListScheduleTopDown() {
unsigned CurCycle = 0;
+ // We're scheduling top-down but we're visiting the regions in
+ // bottom-up order, so we don't know the hazards at the start of a
+ // region. So assume no hazards (this should usually be ok as most
+ // blocks are a single region).
+ HazardRec->Reset();
+
// Release any successors of the special Entry node.
ReleaseSuccessors(&EntrySU);
- // All leaves to Available queue.
+ // Add all leaves to Available queue.
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
// It is available if it has no predecessors.
- if (SUnits[i].Preds.empty()) {
+ if (!SUnits[i].NumPredsLeft && !SUnits[i].isAvailable) {
AvailableQueue.push(&SUnits[i]);
SUnits[i].isAvailable = true;
}
MinDepth = PendingQueue[i]->getDepth();
}
- DEBUG(errs() << "\n*** Examining Available\n";
- LatencyPriorityQueue q = AvailableQueue;
- while (!q.empty()) {
- SUnit *su = q.pop();
- errs() << "Height " << su->getHeight() << ": ";
- su->dump(this);
- });
-
- SUnit *FoundSUnit = 0;
+ DEBUG(dbgs() << "\n*** Examining Available\n"; AvailableQueue.dump(this));
+ SUnit *FoundSUnit = nullptr, *NotPreferredSUnit = nullptr;
bool HasNoopHazards = false;
while (!AvailableQueue.empty()) {
SUnit *CurSUnit = AvailableQueue.pop();
ScheduleHazardRecognizer::HazardType HT =
- HazardRec->getHazardType(CurSUnit);
+ HazardRec->getHazardType(CurSUnit, 0/*no stalls*/);
if (HT == ScheduleHazardRecognizer::NoHazard) {
- FoundSUnit = CurSUnit;
- break;
+ if (HazardRec->ShouldPreferAnother(CurSUnit)) {
+ if (!NotPreferredSUnit) {
+ // If this is the first non-preferred node for this cycle, then
+ // record it and continue searching for a preferred node. If this
+ // is not the first non-preferred node, then treat it as though
+ // there had been a hazard.
+ NotPreferredSUnit = CurSUnit;
+ continue;
+ }
+ } else {
+ FoundSUnit = CurSUnit;
+ break;
+ }
}
// Remember if this is a noop hazard.
NotReady.push_back(CurSUnit);
}
+ // If we have a non-preferred node, push it back onto the available list.
+ // If we did not find a preferred node, then schedule this first
+ // non-preferred node.
+ if (NotPreferredSUnit) {
+ if (!FoundSUnit) {
+ DEBUG(dbgs() << "*** Will schedule a non-preferred instruction...\n");
+ FoundSUnit = NotPreferredSUnit;
+ } else {
+ AvailableQueue.push(NotPreferredSUnit);
+ }
+
+ NotPreferredSUnit = nullptr;
+ }
+
// Add the nodes that aren't ready back onto the available list.
if (!NotReady.empty()) {
AvailableQueue.push_all(NotReady);
NotReady.clear();
}
- // If we found a node to schedule, do it now.
+ // If we found a node to schedule...
if (FoundSUnit) {
+ // If we need to emit noops prior to this instruction, then do so.
+ unsigned NumPreNoops = HazardRec->PreEmitNoops(FoundSUnit);
+ for (unsigned i = 0; i != NumPreNoops; ++i)
+ emitNoop(CurCycle);
+
+ // ... schedule the node...
ScheduleNodeTopDown(FoundSUnit, CurCycle);
HazardRec->EmitInstruction(FoundSUnit);
CycleHasInsts = true;
-
- // If we are using the target-specific hazards, then don't
- // advance the cycle time just because we schedule a node. If
- // the target allows it we can schedule multiple nodes in the
- // same cycle.
- if (!EnablePostRAHazardAvoidance) {
- if (FoundSUnit->Latency) // Don't increment CurCycle for pseudo-ops!
- ++CurCycle;
+ if (HazardRec->atIssueLimit()) {
+ DEBUG(dbgs() << "*** Max instructions per cycle " << CurCycle << '\n');
+ HazardRec->AdvanceCycle();
+ ++CurCycle;
+ CycleHasInsts = false;
}
} else {
if (CycleHasInsts) {
- DEBUG(errs() << "*** Finished cycle " << CurCycle << '\n');
+ DEBUG(dbgs() << "*** Finished cycle " << CurCycle << '\n');
HazardRec->AdvanceCycle();
} else if (!HasNoopHazards) {
// Otherwise, we have a pipeline stall, but no other problem,
// just advance the current cycle and try again.
- DEBUG(errs() << "*** Stall in cycle " << CurCycle << '\n');
+ DEBUG(dbgs() << "*** Stall in cycle " << CurCycle << '\n');
HazardRec->AdvanceCycle();
++NumStalls;
} else {
// Otherwise, we have no instructions to issue and we have instructions
// that will fault if we don't do this right. This is the case for
// processors without pipeline interlocks and other cases.
- DEBUG(errs() << "*** Emitting noop in cycle " << CurCycle << '\n');
- HazardRec->EmitNoop();
- Sequence.push_back(0); // NULL here means noop
- ++NumNoops;
+ emitNoop(CurCycle);
}
++CurCycle;
}
#ifndef NDEBUG
- VerifySchedule(/*isBottomUp=*/false);
-#endif
+ unsigned ScheduledNodes = VerifyScheduledDAG(/*isBottomUp=*/false);
+ unsigned Noops = 0;
+ for (unsigned i = 0, e = Sequence.size(); i != e; ++i)
+ if (!Sequence[i])
+ ++Noops;
+ assert(Sequence.size() - Noops == ScheduledNodes &&
+ "The number of nodes scheduled doesn't match the expected number!");
+#endif // NDEBUG
}
-//===----------------------------------------------------------------------===//
-// Public Constructor Functions
-//===----------------------------------------------------------------------===//
+// EmitSchedule - Emit the machine code in scheduled order.
+void SchedulePostRATDList::EmitSchedule() {
+ RegionBegin = RegionEnd;
+
+ // If first instruction was a DBG_VALUE then put it back.
+ if (FirstDbgValue)
+ BB->splice(RegionEnd, BB, FirstDbgValue);
+
+ // Then re-insert them according to the given schedule.
+ for (unsigned i = 0, e = Sequence.size(); i != e; i++) {
+ if (SUnit *SU = Sequence[i])
+ BB->splice(RegionEnd, BB, SU->getInstr());
+ else
+ // Null SUnit* is a noop.
+ TII->insertNoop(*BB, RegionEnd);
+
+ // Update the Begin iterator, as the first instruction in the block
+ // may have been scheduled later.
+ if (i == 0)
+ RegionBegin = std::prev(RegionEnd);
+ }
-FunctionPass *llvm::createPostRAScheduler(CodeGenOpt::Level OptLevel) {
- return new PostRAScheduler(OptLevel);
+ // Reinsert any remaining debug_values.
+ for (std::vector<std::pair<MachineInstr *, MachineInstr *> >::iterator
+ DI = DbgValues.end(), DE = DbgValues.begin(); DI != DE; --DI) {
+ std::pair<MachineInstr *, MachineInstr *> P = *std::prev(DI);
+ MachineInstr *DbgValue = P.first;
+ MachineBasicBlock::iterator OrigPrivMI = P.second;
+ BB->splice(++OrigPrivMI, BB, DbgValue);
+ }
+ DbgValues.clear();
+ FirstDbgValue = nullptr;
}
projects / oota-llvm.git / blobdiff