//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "post-RA-sched"
-#include "AntiDepBreaker.h"
+#include "llvm/CodeGen/Passes.h"
#include "AggressiveAntiDepBreaker.h"
+#include "AntiDepBreaker.h"
#include "CriticalAntiDepBreaker.h"
-#include "RegisterClassInfo.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/TargetSubtargetInfo.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 "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;
STATISTIC(NumNoops, "Number of noops inserted");
namespace {
class PostRAScheduler : public MachineFunctionPass {
- AliasAnalysis *AA;
const TargetInstrInfo *TII;
RegisterClassInfo RegClassInfo;
/// 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;
- /// LiveRegs - true if the register is live.
- BitVector LiveRegs;
-
/// 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, MachineLoopInfo &MLI, MachineDominatorTree &MDT,
///
void startBlock(MachineBasicBlock *BB);
+ // Set the index of RegionEnd within the current BB.
+ void setEndIndex(unsigned EndIdx) { EndIndex = EndIdx; }
+
/// Initialize the scheduler state for the next scheduling region.
virtual void enterRegion(MachineBasicBlock *bb,
MachineBasicBlock::iterator begin,
MachineBasicBlock::iterator end,
- unsigned endcount);
+ unsigned regioninstrs);
/// Notify that the scheduler has finished scheduling the current region.
virtual void exitRegion();
///
void finishBlock();
- /// FixupKills - Fix register kill flags that have been made
- /// invalid due to scheduling
- ///
- void FixupKills(MachineBasicBlock *MBB);
-
private:
void ReleaseSucc(SUnit *SU, SDep *SuccEdge);
void ReleaseSuccessors(SUnit *SU);
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);
};
}
AliasAnalysis *AA, const RegisterClassInfo &RCI,
TargetSubtargetInfo::AntiDepBreakMode AntiDepMode,
SmallVectorImpl<const TargetRegisterClass*> &CriticalPathRCs)
- : ScheduleDAGInstrs(MF, MLI, MDT, /*IsPostRA=*/true), Topo(SUnits), AA(AA),
- LiveRegs(TRI->getNumRegs())
-{
+ : ScheduleDAGInstrs(MF, MLI, MDT, /*IsPostRA=*/true), AA(AA), EndIndex(0) {
+
const TargetMachine &TM = MF.getTarget();
const InstrItineraryData *InstrItins = TM.getInstrItineraryData();
HazardRec =
TM.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) :
void SchedulePostRATDList::enterRegion(MachineBasicBlock *bb,
MachineBasicBlock::iterator begin,
MachineBasicBlock::iterator end,
- unsigned endcount) {
- ScheduleDAGInstrs::enterRegion(bb, begin, end, endcount);
+ unsigned regioninstrs) {
+ ScheduleDAGInstrs::enterRegion(bb, begin, end, regioninstrs);
Sequence.clear();
}
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++) {
dbgs() << "**** NOOP ****\n";
}
}
+#endif
bool PostRAScheduler::runOnMachineFunction(MachineFunction &Fn) {
TII = Fn.getTarget().getInstrInfo();
static int bbcnt = 0;
if (bbcnt++ % DebugDiv != DebugMod)
continue;
- dbgs() << "*** DEBUG scheduling " << Fn.getFunction()->getName()
+ dbgs() << "*** DEBUG scheduling " << Fn.getName()
<< ":BB#" << MBB->getNumber() << " ***\n";
}
#endif
unsigned Count = MBB->size(), CurrentCount = Count;
for (MachineBasicBlock::iterator I = Current; I != MBB->begin(); ) {
MachineInstr *MI = llvm::prior(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);
+ 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((MBB->begin() == Current || CurrentCount != 0) &&
"Instruction count mismatch!");
Scheduler.enterRegion(MBB, MBB->begin(), Current, CurrentCount);
+ Scheduler.setEndIndex(CurrentCount);
Scheduler.schedule();
Scheduler.exitRegion();
Scheduler.EmitSchedule();
Scheduler.finishBlock();
// Update register kills
- Scheduler.FixupKills(MBB);
+ Scheduler.fixupKills(MBB);
}
return true;
ScheduleDAGInstrs::finishBlock();
}
-/// StartBlockForKills - Initialize register live-range state for updating kills
-///
-void SchedulePostRATDList::StartBlockForKills(MachineBasicBlock *BB) {
- // Start with no live registers.
- LiveRegs.reset();
-
- // Determine the live-out physregs for this block.
- if (!BB->empty() && BB->back().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;
- LiveRegs.set(Reg);
- // Repeat, for all subregs.
- for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg)
- LiveRegs.set(*Subreg);
- }
- }
- 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;
- LiveRegs.set(Reg);
- // Repeat, for all subregs.
- for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg)
- LiveRegs.set(*Subreg);
- }
- }
- }
-}
-
-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 (LiveRegs.test(MO.getReg())) {
- 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 uint16_t *Subreg = TRI->getSubRegisters(SuperReg);
- *Subreg; ++Subreg) {
- if (LiveRegs.test(*Subreg)) {
- 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(dbgs() << "Fixup kills for BB#" << MBB->getNumber() << '\n');
-
- BitVector killedRegs(TRI->getNumRegs());
- 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;
- if (MI->isDebugValue())
- continue;
-
- // 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.isRegMask())
- LiveRegs.clearBitsNotInMask(MO.getRegMask());
- 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;
-
- LiveRegs.reset(Reg);
-
- // Repeat for all subregs.
- for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg)
- LiveRegs.reset(*Subreg);
- }
-
- // 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.reset();
- 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.test(Reg)) {
- kill = true;
- // A register is not killed if any subregs are live...
- for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg) {
- if (LiveRegs.test(*Subreg)) {
- kill = false;
- break;
- }
- }
-
- // If subreg is not live, then register is killed if it became
- // live in this instruction
- if (kill)
- kill = !LiveRegs.test(Reg);
- }
-
- if (MO.isKill() != kill) {
- DEBUG(dbgs() << "Fixing " << MO << " in ");
- // Warning: ToggleKillFlag may invalidate MO.
- ToggleKillFlag(MI, MO);
- DEBUG(MI->dump());
- }
-
- killedRegs.set(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;
-
- LiveRegs.set(Reg);
-
- for (const uint16_t *Subreg = TRI->getSubRegisters(Reg);
- *Subreg; ++Subreg)
- LiveRegs.set(*Subreg);
- }
- }
-}
-
//===----------------------------------------------------------------------===//
// Top-Down Scheduling
//===----------------------------------------------------------------------===//
/// 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) {
dbgs() << "*** Scheduling failed! ***\n";
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(0); // NULL here means noop
+ ++NumNoops;
+}
+
/// ListScheduleTopDown - The main loop of list scheduling for top-down
/// schedulers.
void SchedulePostRATDList::ListScheduleTopDown() {
// Add all leaves to Available queue.
for (unsigned i = 0, e = SUnits.size(); i != e; ++i) {
// It is available if it has no predecessors.
- bool available = SUnits[i].Preds.empty();
- if (available) {
+ if (!SUnits[i].NumPredsLeft && !SUnits[i].isAvailable) {
AvailableQueue.push(&SUnits[i]);
SUnits[i].isAvailable = true;
}
DEBUG(dbgs() << "\n*** Examining Available\n"; AvailableQueue.dump(this));
- SUnit *FoundSUnit = 0;
+ SUnit *FoundSUnit = 0, *NotPreferredSUnit = 0;
bool HasNoopHazards = false;
while (!AvailableQueue.empty()) {
SUnit *CurSUnit = AvailableQueue.pop();
ScheduleHazardRecognizer::HazardType HT =
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 = 0;
+ }
+
// Add the nodes that aren't ready back onto the available list.
if (!NotReady.empty()) {
AvailableQueue.push_all(NotReady);
// 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);
// 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(dbgs() << "*** Emitting noop in cycle " << CurCycle << '\n');
- HazardRec->EmitNoop();
- Sequence.push_back(0); // NULL here means noop
- ++NumNoops;
+ emitNoop(CurCycle);
}
++CurCycle;
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