//
//===----------------------------------------------------------------------===//
-#include "RegisterClassInfo.h"
-#include "RegisterPressure.h"
+#include "llvm/CodeGen/RegisterPressure.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/Target/TargetMachine.h"
+#include "llvm/CodeGen/RegisterClassInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
using namespace llvm;
-/// Increase register pressure for each set impacted by this register class.
+/// Increase pressure for each pressure set provided by TargetRegisterInfo.
static void increaseSetPressure(std::vector<unsigned> &CurrSetPressure,
- std::vector<unsigned> &MaxSetPressure,
- const TargetRegisterClass *RC,
- const TargetRegisterInfo *TRI) {
- unsigned Weight = TRI->getRegClassWeight(RC).RegWeight;
- for (const int *PSet = TRI->getRegClassPressureSets(RC);
- *PSet != -1; ++PSet) {
- CurrSetPressure[*PSet] += Weight;
- if (CurrSetPressure[*PSet] > MaxSetPressure[*PSet])
- MaxSetPressure[*PSet] = CurrSetPressure[*PSet];
- }
+ PSetIterator PSetI) {
+ unsigned Weight = PSetI.getWeight();
+ for (; PSetI.isValid(); ++PSetI)
+ CurrSetPressure[*PSetI] += Weight;
}
-/// Decrease register pressure for each set impacted by this register class.
+/// Decrease pressure for each pressure set provided by TargetRegisterInfo.
static void decreaseSetPressure(std::vector<unsigned> &CurrSetPressure,
- const TargetRegisterClass *RC,
- const TargetRegisterInfo *TRI) {
- unsigned Weight = TRI->getRegClassWeight(RC).RegWeight;
- for (const int *PSet = TRI->getRegClassPressureSets(RC);
- *PSet != -1; ++PSet) {
- assert(CurrSetPressure[*PSet] >= Weight && "register pressure underflow");
- CurrSetPressure[*PSet] -= Weight;
+ PSetIterator PSetI) {
+ unsigned Weight = PSetI.getWeight();
+ for (; PSetI.isValid(); ++PSetI) {
+ assert(CurrSetPressure[*PSetI] >= Weight && "register pressure underflow");
+ CurrSetPressure[*PSetI] -= Weight;
}
}
-/// Directly increase pressure only within this RegisterPressure result.
-void RegisterPressure::increase(const TargetRegisterClass *RC,
- const TargetRegisterInfo *TRI) {
- increaseSetPressure(MaxSetPressure, MaxSetPressure, RC, TRI);
+LLVM_DUMP_METHOD
+void llvm::dumpRegSetPressure(ArrayRef<unsigned> SetPressure,
+ const TargetRegisterInfo *TRI) {
+ bool Empty = true;
+ for (unsigned i = 0, e = SetPressure.size(); i < e; ++i) {
+ if (SetPressure[i] != 0) {
+ dbgs() << TRI->getRegPressureSetName(i) << "=" << SetPressure[i] << '\n';
+ Empty = false;
+ }
+ }
+ if (Empty)
+ dbgs() << "\n";
}
-/// Directly decrease pressure only within this RegisterPressure result.
-void RegisterPressure::decrease(const TargetRegisterClass *RC,
- const TargetRegisterInfo *TRI) {
- decreaseSetPressure(MaxSetPressure, RC, TRI);
+LLVM_DUMP_METHOD
+void RegisterPressure::dump(const TargetRegisterInfo *TRI) const {
+ dbgs() << "Max Pressure: ";
+ dumpRegSetPressure(MaxSetPressure, TRI);
+ dbgs() << "Live In: ";
+ for (unsigned i = 0, e = LiveInRegs.size(); i < e; ++i)
+ dbgs() << PrintVRegOrUnit(LiveInRegs[i], TRI) << " ";
+ dbgs() << '\n';
+ dbgs() << "Live Out: ";
+ for (unsigned i = 0, e = LiveOutRegs.size(); i < e; ++i)
+ dbgs() << PrintVRegOrUnit(LiveOutRegs[i], TRI) << " ";
+ dbgs() << '\n';
}
-/// Increase the current pressure as impacted by this physical register and bump
-/// the high water mark if needed.
-void RegPressureTracker::increasePhysRegPressure(unsigned Reg) {
- increaseSetPressure(CurrSetPressure, P.MaxSetPressure,
- TRI->getMinimalPhysRegClass(Reg), TRI);
+LLVM_DUMP_METHOD
+void RegPressureTracker::dump() const {
+ if (!isTopClosed() || !isBottomClosed()) {
+ dbgs() << "Curr Pressure: ";
+ dumpRegSetPressure(CurrSetPressure, TRI);
+ }
+ P.dump(TRI);
}
-/// Simply decrease the current pressure as impacted by this physcial register.
-void RegPressureTracker::decreasePhysRegPressure(unsigned Reg) {
- decreaseSetPressure(CurrSetPressure, TRI->getMinimalPhysRegClass(Reg), TRI);
+void PressureDiff::dump(const TargetRegisterInfo &TRI) const {
+ for (const PressureChange &Change : *this) {
+ if (!Change.isValid() || Change.getUnitInc() == 0)
+ continue;
+ dbgs() << " " << TRI.getRegPressureSetName(Change.getPSet())
+ << " " << Change.getUnitInc();
+ }
+ dbgs() << '\n';
}
-/// Increase the current pressure as impacted by this virtual register and bump
+/// Increase the current pressure as impacted by these registers and bump
/// the high water mark if needed.
-void RegPressureTracker::increaseVirtRegPressure(unsigned Reg) {
- increaseSetPressure(CurrSetPressure, P.MaxSetPressure,
- MRI->getRegClass(Reg), TRI);
+void RegPressureTracker::increaseRegPressure(ArrayRef<unsigned> RegUnits) {
+ for (unsigned i = 0, e = RegUnits.size(); i != e; ++i) {
+ PSetIterator PSetI = MRI->getPressureSets(RegUnits[i]);
+ unsigned Weight = PSetI.getWeight();
+ for (; PSetI.isValid(); ++PSetI) {
+ CurrSetPressure[*PSetI] += Weight;
+ if (CurrSetPressure[*PSetI] > P.MaxSetPressure[*PSetI]) {
+ P.MaxSetPressure[*PSetI] = CurrSetPressure[*PSetI];
+ }
+ }
+ }
}
-/// Simply decrease the current pressure as impacted by this virtual register.
-void RegPressureTracker::decreaseVirtRegPressure(unsigned Reg) {
- decreaseSetPressure(CurrSetPressure, MRI->getRegClass(Reg), TRI);
+/// Simply decrease the current pressure as impacted by these registers.
+void RegPressureTracker::decreaseRegPressure(ArrayRef<unsigned> RegUnits) {
+ for (unsigned I = 0, E = RegUnits.size(); I != E; ++I)
+ decreaseSetPressure(CurrSetPressure, MRI->getPressureSets(RegUnits[I]));
}
/// Clear the result so it can be used for another round of pressure tracking.
LiveInRegs.clear();
}
+const LiveRange *RegPressureTracker::getLiveRange(unsigned Reg) const {
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ return &LIS->getInterval(Reg);
+ return LIS->getCachedRegUnit(Reg);
+}
+
+void RegPressureTracker::reset() {
+ MBB = nullptr;
+ LIS = nullptr;
+
+ CurrSetPressure.clear();
+ LiveThruPressure.clear();
+ P.MaxSetPressure.clear();
+
+ if (RequireIntervals)
+ static_cast<IntervalPressure&>(P).reset();
+ else
+ static_cast<RegionPressure&>(P).reset();
+
+ LiveRegs.PhysRegs.clear();
+ LiveRegs.VirtRegs.clear();
+ UntiedDefs.clear();
+}
+
/// Setup the RegPressureTracker.
///
/// TODO: Add support for pressure without LiveIntervals.
const RegisterClassInfo *rci,
const LiveIntervals *lis,
const MachineBasicBlock *mbb,
- MachineBasicBlock::const_iterator pos)
+ MachineBasicBlock::const_iterator pos,
+ bool ShouldTrackUntiedDefs)
{
+ reset();
+
MF = mf;
- TRI = MF->getTarget().getRegisterInfo();
+ TRI = MF->getSubtarget().getRegisterInfo();
RCI = rci;
MRI = &MF->getRegInfo();
MBB = mbb;
+ TrackUntiedDefs = ShouldTrackUntiedDefs;
if (RequireIntervals) {
assert(lis && "IntervalPressure requires LiveIntervals");
}
CurrPos = pos;
- while (CurrPos != MBB->end() && CurrPos->isDebugValue())
- ++CurrPos;
-
CurrSetPressure.assign(TRI->getNumRegPressureSets(), 0);
- if (RequireIntervals)
- static_cast<IntervalPressure&>(P).reset();
- else
- static_cast<RegionPressure&>(P).reset();
P.MaxSetPressure = CurrSetPressure;
- LivePhysRegs.clear();
- LivePhysRegs.setUniverse(TRI->getNumRegs());
- LiveVirtRegs.clear();
- LiveVirtRegs.setUniverse(MRI->getNumVirtRegs());
+ LiveRegs.PhysRegs.setUniverse(TRI->getNumRegs());
+ LiveRegs.VirtRegs.setUniverse(MRI->getNumVirtRegs());
+ if (TrackUntiedDefs)
+ UntiedDefs.setUniverse(MRI->getNumVirtRegs());
}
/// Does this pressure result have a valid top position and live ins.
MachineBasicBlock::const_iterator());
}
+
+SlotIndex RegPressureTracker::getCurrSlot() const {
+ MachineBasicBlock::const_iterator IdxPos = CurrPos;
+ while (IdxPos != MBB->end() && IdxPos->isDebugValue())
+ ++IdxPos;
+ if (IdxPos == MBB->end())
+ return LIS->getMBBEndIdx(MBB);
+ return LIS->getInstructionIndex(IdxPos).getRegSlot();
+}
+
/// Set the boundary for the top of the region and summarize live ins.
void RegPressureTracker::closeTop() {
if (RequireIntervals)
- static_cast<IntervalPressure&>(P).TopIdx =
- LIS->getInstructionIndex(CurrPos).getRegSlot();
+ static_cast<IntervalPressure&>(P).TopIdx = getCurrSlot();
else
static_cast<RegionPressure&>(P).TopPos = CurrPos;
assert(P.LiveInRegs.empty() && "inconsistent max pressure result");
- P.LiveInRegs.reserve(LivePhysRegs.size() + LiveVirtRegs.size());
- P.LiveInRegs.append(LivePhysRegs.begin(), LivePhysRegs.end());
- for (SparseSet<unsigned>::const_iterator I =
- LiveVirtRegs.begin(), E = LiveVirtRegs.end(); I != E; ++I)
- P.LiveInRegs.push_back(*I);
- std::sort(P.LiveInRegs.begin(), P.LiveInRegs.end());
- P.LiveInRegs.erase(std::unique(P.LiveInRegs.begin(), P.LiveInRegs.end()),
- P.LiveInRegs.end());
+ P.LiveInRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size());
+ P.LiveInRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end());
+ P.LiveInRegs.append(LiveRegs.VirtRegs.begin(), LiveRegs.VirtRegs.end());
}
/// Set the boundary for the bottom of the region and summarize live outs.
void RegPressureTracker::closeBottom() {
if (RequireIntervals)
- if (CurrPos == MBB->end())
- static_cast<IntervalPressure&>(P).BottomIdx = LIS->getMBBEndIdx(MBB);
- else
- static_cast<IntervalPressure&>(P).BottomIdx =
- LIS->getInstructionIndex(CurrPos).getRegSlot();
+ static_cast<IntervalPressure&>(P).BottomIdx = getCurrSlot();
else
static_cast<RegionPressure&>(P).BottomPos = CurrPos;
assert(P.LiveOutRegs.empty() && "inconsistent max pressure result");
- P.LiveOutRegs.reserve(LivePhysRegs.size() + LiveVirtRegs.size());
- P.LiveOutRegs.append(LivePhysRegs.begin(), LivePhysRegs.end());
- for (SparseSet<unsigned>::const_iterator I =
- LiveVirtRegs.begin(), E = LiveVirtRegs.end(); I != E; ++I)
- P.LiveOutRegs.push_back(*I);
- std::sort(P.LiveOutRegs.begin(), P.LiveOutRegs.end());
- P.LiveOutRegs.erase(std::unique(P.LiveOutRegs.begin(), P.LiveOutRegs.end()),
- P.LiveOutRegs.end());
+ P.LiveOutRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size());
+ P.LiveOutRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end());
+ P.LiveOutRegs.append(LiveRegs.VirtRegs.begin(), LiveRegs.VirtRegs.end());
}
/// Finalize the region boundaries and record live ins and live outs.
void RegPressureTracker::closeRegion() {
if (!isTopClosed() && !isBottomClosed()) {
- assert(LivePhysRegs.empty() && LiveVirtRegs.empty() &&
+ assert(LiveRegs.PhysRegs.empty() && LiveRegs.VirtRegs.empty() &&
"no region boundary");
return;
}
// If both top and bottom are closed, do nothing.
}
-/// Return true if Reg aliases a register in Regs SparseSet.
-static bool hasRegAlias(unsigned Reg, SparseSet<unsigned> &Regs,
- const TargetRegisterInfo *TRI) {
- assert(!TargetRegisterInfo::isVirtualRegister(Reg) && "only for physregs");
- for (const uint16_t *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) {
- if (Regs.count(*Alias))
- return true;
- }
- return false;
-}
-
-/// Return true if Reg aliases a register in unsorted Regs SmallVector.
-/// This is only valid for physical registers.
-static SmallVectorImpl<unsigned>::iterator
-findRegAlias(unsigned Reg, SmallVectorImpl<unsigned> &Regs,
- const TargetRegisterInfo *TRI) {
- for (const uint16_t *Alias = TRI->getOverlaps(Reg); *Alias; ++Alias) {
- SmallVectorImpl<unsigned>::iterator I =
- std::find(Regs.begin(), Regs.end(), *Alias);
- if (I != Regs.end())
- return I;
+/// The register tracker is unaware of global liveness so ignores normal
+/// live-thru ranges. However, two-address or coalesced chains can also lead
+/// to live ranges with no holes. Count these to inform heuristics that we
+/// can never drop below this pressure.
+void RegPressureTracker::initLiveThru(const RegPressureTracker &RPTracker) {
+ LiveThruPressure.assign(TRI->getNumRegPressureSets(), 0);
+ assert(isBottomClosed() && "need bottom-up tracking to intialize.");
+ for (unsigned i = 0, e = P.LiveOutRegs.size(); i < e; ++i) {
+ unsigned Reg = P.LiveOutRegs[i];
+ if (TargetRegisterInfo::isVirtualRegister(Reg)
+ && !RPTracker.hasUntiedDef(Reg)) {
+ increaseSetPressure(LiveThruPressure, MRI->getPressureSets(Reg));
+ }
}
- return Regs.end();
}
-/// Return true if Reg can be inserted into Regs SmallVector. For virtual
-/// register, do a linear search. For physical registers check for aliases.
-static SmallVectorImpl<unsigned>::iterator
-findReg(unsigned Reg, bool isVReg, SmallVectorImpl<unsigned> &Regs,
- const TargetRegisterInfo *TRI) {
- if(isVReg)
- return std::find(Regs.begin(), Regs.end(), Reg);
- return findRegAlias(Reg, Regs, TRI);
+/// \brief Convenient wrapper for checking membership in RegisterOperands.
+/// (std::count() doesn't have an early exit).
+static bool containsReg(ArrayRef<unsigned> RegUnits, unsigned RegUnit) {
+ return std::find(RegUnits.begin(), RegUnits.end(), RegUnit) != RegUnits.end();
}
+namespace {
/// Collect this instruction's unique uses and defs into SmallVectors for
/// processing defs and uses in order.
-template<bool isVReg>
-struct RegisterOperands {
+///
+/// FIXME: always ignore tied opers
+class RegisterOperands {
+ const TargetRegisterInfo *TRI;
+ const MachineRegisterInfo *MRI;
+ bool IgnoreDead;
+
+public:
SmallVector<unsigned, 8> Uses;
SmallVector<unsigned, 8> Defs;
SmallVector<unsigned, 8> DeadDefs;
+ RegisterOperands(const TargetRegisterInfo *tri,
+ const MachineRegisterInfo *mri, bool ID = false):
+ TRI(tri), MRI(mri), IgnoreDead(ID) {}
+
/// Push this operand's register onto the correct vector.
- void collect(const MachineOperand &MO, const TargetRegisterInfo *TRI) {
- if (MO.readsReg()) {
- if (findReg(MO.getReg(), isVReg, Uses, TRI) == Uses.end())
- Uses.push_back(MO.getReg());
- }
+ void collect(const MachineOperand &MO) {
+ if (!MO.isReg() || !MO.getReg())
+ return;
+ if (MO.readsReg())
+ pushRegUnits(MO.getReg(), Uses);
if (MO.isDef()) {
if (MO.isDead()) {
- if (findReg(MO.getReg(), isVReg, DeadDefs, TRI) == DeadDefs.end())
- DeadDefs.push_back(MO.getReg());
+ if (!IgnoreDead)
+ pushRegUnits(MO.getReg(), DeadDefs);
}
- else {
- if (findReg(MO.getReg(), isVReg, Defs, TRI) == Defs.end())
- Defs.push_back(MO.getReg());
+ else
+ pushRegUnits(MO.getReg(), Defs);
+ }
+ }
+
+protected:
+ void pushRegUnits(unsigned Reg, SmallVectorImpl<unsigned> &RegUnits) {
+ if (TargetRegisterInfo::isVirtualRegister(Reg)) {
+ if (containsReg(RegUnits, Reg))
+ return;
+ RegUnits.push_back(Reg);
+ }
+ else if (MRI->isAllocatable(Reg)) {
+ for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) {
+ if (containsReg(RegUnits, *Units))
+ continue;
+ RegUnits.push_back(*Units);
}
}
}
};
-typedef RegisterOperands<false> PhysRegOperands;
-typedef RegisterOperands<true> VirtRegOperands;
+} // namespace
/// Collect physical and virtual register operands.
static void collectOperands(const MachineInstr *MI,
- PhysRegOperands &PhysRegOpers,
- VirtRegOperands &VirtRegOpers,
- const TargetRegisterInfo *TRI,
- const RegisterClassInfo *RCI) {
- for(ConstMIBundleOperands OperI(MI); OperI.isValid(); ++OperI) {
- const MachineOperand &MO = *OperI;
- if (!MO.isReg() || !MO.getReg())
- continue;
+ RegisterOperands &RegOpers) {
+ for (ConstMIBundleOperands OperI(MI); OperI.isValid(); ++OperI)
+ RegOpers.collect(*OperI);
- if (TargetRegisterInfo::isVirtualRegister(MO.getReg()))
- VirtRegOpers.collect(MO, TRI);
- else if (RCI->isAllocatable(MO.getReg()))
- PhysRegOpers.collect(MO, TRI);
- }
// Remove redundant physreg dead defs.
- for (unsigned i = PhysRegOpers.DeadDefs.size(); i > 0; --i) {
- unsigned Reg = PhysRegOpers.DeadDefs[i-1];
- if (findRegAlias(Reg, PhysRegOpers.Defs, TRI) != PhysRegOpers.Defs.end())
- PhysRegOpers.DeadDefs.erase(&PhysRegOpers.DeadDefs[i-1]);
- }
+ SmallVectorImpl<unsigned>::iterator I =
+ std::remove_if(RegOpers.DeadDefs.begin(), RegOpers.DeadDefs.end(),
+ std::bind1st(std::ptr_fun(containsReg), RegOpers.Defs));
+ RegOpers.DeadDefs.erase(I, RegOpers.DeadDefs.end());
}
-/// Add PhysReg to the live in set and increase max pressure.
-void RegPressureTracker::discoverPhysLiveIn(unsigned Reg) {
- assert(!LivePhysRegs.count(Reg) && "avoid bumping max pressure twice");
- if (findRegAlias(Reg, P.LiveInRegs, TRI) == P.LiveInRegs.end())
+/// Initialize an array of N PressureDiffs.
+void PressureDiffs::init(unsigned N) {
+ Size = N;
+ if (N <= Max) {
+ memset(PDiffArray, 0, N * sizeof(PressureDiff));
return;
+ }
+ Max = Size;
+ free(PDiffArray);
+ PDiffArray = reinterpret_cast<PressureDiff*>(calloc(N, sizeof(PressureDiff)));
+}
- // At live in discovery, unconditionally increase the high water mark.
- P.LiveInRegs.push_back(Reg);
- P.increase(TRI->getMinimalPhysRegClass(Reg), TRI);
+/// Add a change in pressure to the pressure diff of a given instruction.
+void PressureDiff::addPressureChange(unsigned RegUnit, bool IsDec,
+ const MachineRegisterInfo *MRI) {
+ PSetIterator PSetI = MRI->getPressureSets(RegUnit);
+ int Weight = IsDec ? -PSetI.getWeight() : PSetI.getWeight();
+ for (; PSetI.isValid(); ++PSetI) {
+ // Find an existing entry in the pressure diff for this PSet.
+ PressureDiff::iterator I = begin(), E = end();
+ for (; I != E && I->isValid(); ++I) {
+ if (I->getPSet() >= *PSetI)
+ break;
+ }
+ // If all pressure sets are more constrained, skip the remaining PSets.
+ if (I == E)
+ break;
+ // Insert this PressureChange.
+ if (!I->isValid() || I->getPSet() != *PSetI) {
+ PressureChange PTmp = PressureChange(*PSetI);
+ for (PressureDiff::iterator J = I; J != E && PTmp.isValid(); ++J)
+ std::swap(*J,PTmp);
+ }
+ // Update the units for this pressure set.
+ I->setUnitInc(I->getUnitInc() + Weight);
+ }
}
-/// Add PhysReg to the live out set and increase max pressure.
-void RegPressureTracker::discoverPhysLiveOut(unsigned Reg) {
- assert(!LivePhysRegs.count(Reg) && "avoid bumping max pressure twice");
- if (findRegAlias(Reg, P.LiveOutRegs, TRI) == P.LiveOutRegs.end())
- return;
+/// Record the pressure difference induced by the given operand list.
+static void collectPDiff(PressureDiff &PDiff, RegisterOperands &RegOpers,
+ const MachineRegisterInfo *MRI) {
+ assert(!PDiff.begin()->isValid() && "stale PDiff");
- // At live out discovery, unconditionally increase the high water mark.
- P.LiveOutRegs.push_back(Reg);
- P.increase(TRI->getMinimalPhysRegClass(Reg), TRI);
+ for (unsigned i = 0, e = RegOpers.Defs.size(); i != e; ++i)
+ PDiff.addPressureChange(RegOpers.Defs[i], true, MRI);
+
+ for (unsigned i = 0, e = RegOpers.Uses.size(); i != e; ++i)
+ PDiff.addPressureChange(RegOpers.Uses[i], false, MRI);
}
-/// Add VirtReg to the live in set and increase max pressure.
-void RegPressureTracker::discoverVirtLiveIn(unsigned Reg) {
- assert(!LiveVirtRegs.count(Reg) && "avoid bumping max pressure twice");
- if (std::find(P.LiveInRegs.begin(), P.LiveInRegs.end(), Reg) !=
- P.LiveInRegs.end())
+/// Force liveness of registers.
+void RegPressureTracker::addLiveRegs(ArrayRef<unsigned> Regs) {
+ for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
+ if (LiveRegs.insert(Regs[i]))
+ increaseRegPressure(Regs[i]);
+ }
+}
+
+/// Add Reg to the live in set and increase max pressure.
+void RegPressureTracker::discoverLiveIn(unsigned Reg) {
+ assert(!LiveRegs.contains(Reg) && "avoid bumping max pressure twice");
+ if (containsReg(P.LiveInRegs, Reg))
return;
// At live in discovery, unconditionally increase the high water mark.
P.LiveInRegs.push_back(Reg);
- P.increase(MRI->getRegClass(Reg), TRI);
+ increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg));
}
-/// Add VirtReg to the live out set and increase max pressure.
-void RegPressureTracker::discoverVirtLiveOut(unsigned Reg) {
- assert(!LiveVirtRegs.count(Reg) && "avoid bumping max pressure twice");
- if (std::find(P.LiveOutRegs.begin(), P.LiveOutRegs.end(), Reg) !=
- P.LiveOutRegs.end())
+/// Add Reg to the live out set and increase max pressure.
+void RegPressureTracker::discoverLiveOut(unsigned Reg) {
+ assert(!LiveRegs.contains(Reg) && "avoid bumping max pressure twice");
+ if (containsReg(P.LiveOutRegs, Reg))
return;
// At live out discovery, unconditionally increase the high water mark.
P.LiveOutRegs.push_back(Reg);
- P.increase(MRI->getRegClass(Reg), TRI);
+ increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg));
}
-/// Recede across the previous instruction.
-bool RegPressureTracker::recede() {
+/// Recede across the previous instruction. If LiveUses is provided, record any
+/// RegUnits that are made live by the current instruction's uses. This includes
+/// registers that are both defined and used by the instruction. If a pressure
+/// difference pointer is provided record the changes is pressure caused by this
+/// instruction independent of liveness.
+bool RegPressureTracker::recede(SmallVectorImpl<unsigned> *LiveUses,
+ PressureDiff *PDiff) {
// Check for the top of the analyzable region.
if (CurrPos == MBB->begin()) {
closeRegion();
static_cast<RegionPressure&>(P).openTop(CurrPos);
// Find the previous instruction.
- while (--CurrPos != MBB->begin() && CurrPos->isDebugValue());
+ do
+ --CurrPos;
+ while (CurrPos != MBB->begin() && CurrPos->isDebugValue());
if (CurrPos->isDebugValue()) {
closeRegion();
if (RequireIntervals && isTopClosed())
static_cast<IntervalPressure&>(P).openTop(SlotIdx);
- PhysRegOperands PhysRegOpers;
- VirtRegOperands VirtRegOpers;
- collectOperands(CurrPos, PhysRegOpers, VirtRegOpers, TRI, RCI);
+ RegisterOperands RegOpers(TRI, MRI);
+ collectOperands(CurrPos, RegOpers);
+
+ if (PDiff)
+ collectPDiff(*PDiff, RegOpers, MRI);
// Boost pressure for all dead defs together.
- for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
- increasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
- increaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
- decreasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
- decreaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+ increaseRegPressure(RegOpers.DeadDefs);
+ decreaseRegPressure(RegOpers.DeadDefs);
// Kill liveness at live defs.
// TODO: consider earlyclobbers?
- for (unsigned i = 0; i < PhysRegOpers.Defs.size(); ++i) {
- unsigned Reg = PhysRegOpers.Defs[i];
- if (LivePhysRegs.erase(Reg))
- decreasePhysRegPressure(Reg);
- else
- discoverPhysLiveOut(Reg);
- }
- for (unsigned i = 0; i < VirtRegOpers.Defs.size(); ++i) {
- unsigned Reg = VirtRegOpers.Defs[i];
- if (LiveVirtRegs.erase(Reg))
- decreaseVirtRegPressure(Reg);
- else
- discoverVirtLiveOut(Reg);
+ for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Defs[i];
+ bool DeadDef = false;
+ if (RequireIntervals) {
+ const LiveRange *LR = getLiveRange(Reg);
+ if (LR) {
+ LiveQueryResult LRQ = LR->Query(SlotIdx);
+ DeadDef = LRQ.isDeadDef();
+ }
+ }
+ if (DeadDef) {
+ // LiveIntervals knows this is a dead even though it's MachineOperand is
+ // not flagged as such. Since this register will not be recorded as
+ // live-out, increase its PDiff value to avoid underflowing pressure.
+ if (PDiff)
+ PDiff->addPressureChange(Reg, false, MRI);
+ } else {
+ if (LiveRegs.erase(Reg))
+ decreaseRegPressure(Reg);
+ else
+ discoverLiveOut(Reg);
+ }
}
// Generate liveness for uses.
- for (unsigned i = 0; i < PhysRegOpers.Uses.size(); ++i) {
- unsigned Reg = PhysRegOpers.Uses[i];
- if (!hasRegAlias(Reg, LivePhysRegs, TRI)) {
- increasePhysRegPressure(Reg);
- LivePhysRegs.insert(Reg);
- }
- }
- for (unsigned i = 0; i < VirtRegOpers.Uses.size(); ++i) {
- unsigned Reg = VirtRegOpers.Uses[i];
- if (!LiveVirtRegs.count(Reg)) {
+ for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Uses[i];
+ if (!LiveRegs.contains(Reg)) {
// Adjust liveouts if LiveIntervals are available.
if (RequireIntervals) {
- const LiveInterval *LI = &LIS->getInterval(Reg);
- if (!LI->killedAt(SlotIdx))
- discoverVirtLiveOut(Reg);
+ const LiveRange *LR = getLiveRange(Reg);
+ if (LR) {
+ LiveQueryResult LRQ = LR->Query(SlotIdx);
+ if (!LRQ.isKill() && !LRQ.valueDefined())
+ discoverLiveOut(Reg);
+ }
}
- increaseVirtRegPressure(Reg);
- LiveVirtRegs.insert(Reg);
+ increaseRegPressure(Reg);
+ LiveRegs.insert(Reg);
+ if (LiveUses && !containsReg(*LiveUses, Reg))
+ LiveUses->push_back(Reg);
+ }
+ }
+ if (TrackUntiedDefs) {
+ for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Defs[i];
+ if (TargetRegisterInfo::isVirtualRegister(Reg) && !LiveRegs.contains(Reg))
+ UntiedDefs.insert(Reg);
}
}
return true;
/// Advance across the current instruction.
bool RegPressureTracker::advance() {
+ assert(!TrackUntiedDefs && "unsupported mode");
+
// Check for the bottom of the analyzable region.
if (CurrPos == MBB->end()) {
closeRegion();
SlotIndex SlotIdx;
if (RequireIntervals)
- SlotIdx = LIS->getInstructionIndex(CurrPos).getRegSlot();
+ SlotIdx = getCurrSlot();
// Open the bottom of the region using slot indexes.
if (isBottomClosed()) {
static_cast<RegionPressure&>(P).openBottom(CurrPos);
}
- PhysRegOperands PhysRegOpers;
- VirtRegOperands VirtRegOpers;
- collectOperands(CurrPos, PhysRegOpers, VirtRegOpers, TRI, RCI);
-
- // Kill liveness at last uses.
- for (unsigned i = 0; i < PhysRegOpers.Uses.size(); ++i) {
- unsigned Reg = PhysRegOpers.Uses[i];
- if (!hasRegAlias(Reg, LivePhysRegs, TRI))
- discoverPhysLiveIn(Reg);
+ RegisterOperands RegOpers(TRI, MRI);
+ collectOperands(CurrPos, RegOpers);
+
+ for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Uses[i];
+ // Discover live-ins.
+ bool isLive = LiveRegs.contains(Reg);
+ if (!isLive)
+ discoverLiveIn(Reg);
+ // Kill liveness at last uses.
+ bool lastUse = false;
+ if (RequireIntervals) {
+ const LiveRange *LR = getLiveRange(Reg);
+ lastUse = LR && LR->Query(SlotIdx).isKill();
+ }
else {
- // Allocatable physregs are always single-use before regalloc.
- decreasePhysRegPressure(Reg);
- LivePhysRegs.erase(Reg);
+ // Allocatable physregs are always single-use before register rewriting.
+ lastUse = !TargetRegisterInfo::isVirtualRegister(Reg);
}
+ if (lastUse && isLive) {
+ LiveRegs.erase(Reg);
+ decreaseRegPressure(Reg);
+ }
+ else if (!lastUse && !isLive)
+ increaseRegPressure(Reg);
}
- for (unsigned i = 0; i < VirtRegOpers.Uses.size(); ++i) {
- unsigned Reg = VirtRegOpers.Uses[i];
+
+ // Generate liveness for defs.
+ for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Defs[i];
+ if (LiveRegs.insert(Reg))
+ increaseRegPressure(Reg);
+ }
+
+ // Boost pressure for all dead defs together.
+ increaseRegPressure(RegOpers.DeadDefs);
+ decreaseRegPressure(RegOpers.DeadDefs);
+
+ // Find the next instruction.
+ do
+ ++CurrPos;
+ while (CurrPos != MBB->end() && CurrPos->isDebugValue());
+ return true;
+}
+
+/// Find the max change in excess pressure across all sets.
+static void computeExcessPressureDelta(ArrayRef<unsigned> OldPressureVec,
+ ArrayRef<unsigned> NewPressureVec,
+ RegPressureDelta &Delta,
+ const RegisterClassInfo *RCI,
+ ArrayRef<unsigned> LiveThruPressureVec) {
+ Delta.Excess = PressureChange();
+ for (unsigned i = 0, e = OldPressureVec.size(); i < e; ++i) {
+ unsigned POld = OldPressureVec[i];
+ unsigned PNew = NewPressureVec[i];
+ int PDiff = (int)PNew - (int)POld;
+ if (!PDiff) // No change in this set in the common case.
+ continue;
+ // Only consider change beyond the limit.
+ unsigned Limit = RCI->getRegPressureSetLimit(i);
+ if (!LiveThruPressureVec.empty())
+ Limit += LiveThruPressureVec[i];
+
+ if (Limit > POld) {
+ if (Limit > PNew)
+ PDiff = 0; // Under the limit
+ else
+ PDiff = PNew - Limit; // Just exceeded limit.
+ }
+ else if (Limit > PNew)
+ PDiff = Limit - POld; // Just obeyed limit.
+
+ if (PDiff) {
+ Delta.Excess = PressureChange(i);
+ Delta.Excess.setUnitInc(PDiff);
+ break;
+ }
+ }
+}
+
+/// Find the max change in max pressure that either surpasses a critical PSet
+/// limit or exceeds the current MaxPressureLimit.
+///
+/// FIXME: comparing each element of the old and new MaxPressure vectors here is
+/// silly. It's done now to demonstrate the concept but will go away with a
+/// RegPressureTracker API change to work with pressure differences.
+static void computeMaxPressureDelta(ArrayRef<unsigned> OldMaxPressureVec,
+ ArrayRef<unsigned> NewMaxPressureVec,
+ ArrayRef<PressureChange> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit,
+ RegPressureDelta &Delta) {
+ Delta.CriticalMax = PressureChange();
+ Delta.CurrentMax = PressureChange();
+
+ unsigned CritIdx = 0, CritEnd = CriticalPSets.size();
+ for (unsigned i = 0, e = OldMaxPressureVec.size(); i < e; ++i) {
+ unsigned POld = OldMaxPressureVec[i];
+ unsigned PNew = NewMaxPressureVec[i];
+ if (PNew == POld) // No change in this set in the common case.
+ continue;
+
+ if (!Delta.CriticalMax.isValid()) {
+ while (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() < i)
+ ++CritIdx;
+
+ if (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() == i) {
+ int PDiff = (int)PNew - (int)CriticalPSets[CritIdx].getUnitInc();
+ if (PDiff > 0) {
+ Delta.CriticalMax = PressureChange(i);
+ Delta.CriticalMax.setUnitInc(PDiff);
+ }
+ }
+ }
+ // Find the first increase above MaxPressureLimit.
+ // (Ignores negative MDiff).
+ if (!Delta.CurrentMax.isValid() && PNew > MaxPressureLimit[i]) {
+ Delta.CurrentMax = PressureChange(i);
+ Delta.CurrentMax.setUnitInc(PNew - POld);
+ if (CritIdx == CritEnd || Delta.CriticalMax.isValid())
+ break;
+ }
+ }
+}
+
+/// Record the upward impact of a single instruction on current register
+/// pressure. Unlike the advance/recede pressure tracking interface, this does
+/// not discover live in/outs.
+///
+/// This is intended for speculative queries. It leaves pressure inconsistent
+/// with the current position, so must be restored by the caller.
+void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) {
+ assert(!MI->isDebugValue() && "Expect a nondebug instruction.");
+
+ // Account for register pressure similar to RegPressureTracker::recede().
+ RegisterOperands RegOpers(TRI, MRI, /*IgnoreDead=*/true);
+ collectOperands(MI, RegOpers);
+
+ // Boost max pressure for all dead defs together.
+ // Since CurrSetPressure and MaxSetPressure
+ increaseRegPressure(RegOpers.DeadDefs);
+ decreaseRegPressure(RegOpers.DeadDefs);
+
+ // Kill liveness at live defs.
+ for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Defs[i];
+ bool DeadDef = false;
if (RequireIntervals) {
- const LiveInterval *LI = &LIS->getInterval(Reg);
- if (LI->killedAt(SlotIdx)) {
- if (LiveVirtRegs.erase(Reg))
- decreaseVirtRegPressure(Reg);
- else
- discoverVirtLiveIn(Reg);
+ const LiveRange *LR = getLiveRange(Reg);
+ if (LR) {
+ SlotIndex SlotIdx = LIS->getInstructionIndex(MI);
+ LiveQueryResult LRQ = LR->Query(SlotIdx);
+ DeadDef = LRQ.isDeadDef();
}
}
- else if (!LiveVirtRegs.count(Reg)) {
- discoverVirtLiveIn(Reg);
- increaseVirtRegPressure(Reg);
+ if (!DeadDef) {
+ if (!containsReg(RegOpers.Uses, Reg))
+ decreaseRegPressure(Reg);
}
}
+ // Generate liveness for uses.
+ for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Uses[i];
+ if (!LiveRegs.contains(Reg))
+ increaseRegPressure(Reg);
+ }
+}
- // Generate liveness for defs.
- for (unsigned i = 0; i < PhysRegOpers.Defs.size(); ++i) {
- unsigned Reg = PhysRegOpers.Defs[i];
- if (!hasRegAlias(Reg, LivePhysRegs, TRI)) {
- increasePhysRegPressure(Reg);
- LivePhysRegs.insert(Reg);
+/// Consider the pressure increase caused by traversing this instruction
+/// bottom-up. Find the pressure set with the most change beyond its pressure
+/// limit based on the tracker's current pressure, and return the change in
+/// number of register units of that pressure set introduced by this
+/// instruction.
+///
+/// This assumes that the current LiveOut set is sufficient.
+///
+/// This is expensive for an on-the-fly query because it calls
+/// bumpUpwardPressure to recompute the pressure sets based on current
+/// liveness. This mainly exists to verify correctness, e.g. with
+/// -verify-misched. getUpwardPressureDelta is the fast version of this query
+/// that uses the per-SUnit cache of the PressureDiff.
+void RegPressureTracker::
+getMaxUpwardPressureDelta(const MachineInstr *MI, PressureDiff *PDiff,
+ RegPressureDelta &Delta,
+ ArrayRef<PressureChange> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit) {
+ // Snapshot Pressure.
+ // FIXME: The snapshot heap space should persist. But I'm planning to
+ // summarize the pressure effect so we don't need to snapshot at all.
+ std::vector<unsigned> SavedPressure = CurrSetPressure;
+ std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
+
+ bumpUpwardPressure(MI);
+
+ computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, RCI,
+ LiveThruPressure);
+ computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
+ MaxPressureLimit, Delta);
+ assert(Delta.CriticalMax.getUnitInc() >= 0 &&
+ Delta.CurrentMax.getUnitInc() >= 0 && "cannot decrease max pressure");
+
+ // Restore the tracker's state.
+ P.MaxSetPressure.swap(SavedMaxPressure);
+ CurrSetPressure.swap(SavedPressure);
+
+#ifndef NDEBUG
+ if (!PDiff)
+ return;
+
+ // Check if the alternate algorithm yields the same result.
+ RegPressureDelta Delta2;
+ getUpwardPressureDelta(MI, *PDiff, Delta2, CriticalPSets, MaxPressureLimit);
+ if (Delta != Delta2) {
+ dbgs() << "PDiff: ";
+ PDiff->dump(*TRI);
+ dbgs() << "DELTA: " << *MI;
+ if (Delta.Excess.isValid())
+ dbgs() << "Excess1 " << TRI->getRegPressureSetName(Delta.Excess.getPSet())
+ << " " << Delta.Excess.getUnitInc() << "\n";
+ if (Delta.CriticalMax.isValid())
+ dbgs() << "Critic1 " << TRI->getRegPressureSetName(Delta.CriticalMax.getPSet())
+ << " " << Delta.CriticalMax.getUnitInc() << "\n";
+ if (Delta.CurrentMax.isValid())
+ dbgs() << "CurrMx1 " << TRI->getRegPressureSetName(Delta.CurrentMax.getPSet())
+ << " " << Delta.CurrentMax.getUnitInc() << "\n";
+ if (Delta2.Excess.isValid())
+ dbgs() << "Excess2 " << TRI->getRegPressureSetName(Delta2.Excess.getPSet())
+ << " " << Delta2.Excess.getUnitInc() << "\n";
+ if (Delta2.CriticalMax.isValid())
+ dbgs() << "Critic2 " << TRI->getRegPressureSetName(Delta2.CriticalMax.getPSet())
+ << " " << Delta2.CriticalMax.getUnitInc() << "\n";
+ if (Delta2.CurrentMax.isValid())
+ dbgs() << "CurrMx2 " << TRI->getRegPressureSetName(Delta2.CurrentMax.getPSet())
+ << " " << Delta2.CurrentMax.getUnitInc() << "\n";
+ llvm_unreachable("RegP Delta Mismatch");
+ }
+#endif
+}
+
+/// This is the fast version of querying register pressure that does not
+/// directly depend on current liveness.
+///
+/// @param Delta captures information needed for heuristics.
+///
+/// @param CriticalPSets Are the pressure sets that are known to exceed some
+/// limit within the region, not necessarily at the current position.
+///
+/// @param MaxPressureLimit Is the max pressure within the region, not
+/// necessarily at the current position.
+void RegPressureTracker::
+getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff,
+ RegPressureDelta &Delta,
+ ArrayRef<PressureChange> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit) const {
+ unsigned CritIdx = 0, CritEnd = CriticalPSets.size();
+ for (PressureDiff::const_iterator
+ PDiffI = PDiff.begin(), PDiffE = PDiff.end();
+ PDiffI != PDiffE && PDiffI->isValid(); ++PDiffI) {
+
+ unsigned PSetID = PDiffI->getPSet();
+ unsigned Limit = RCI->getRegPressureSetLimit(PSetID);
+ if (!LiveThruPressure.empty())
+ Limit += LiveThruPressure[PSetID];
+
+ unsigned POld = CurrSetPressure[PSetID];
+ unsigned MOld = P.MaxSetPressure[PSetID];
+ unsigned MNew = MOld;
+ // Ignore DeadDefs here because they aren't captured by PressureChange.
+ unsigned PNew = POld + PDiffI->getUnitInc();
+ assert((PDiffI->getUnitInc() >= 0) == (PNew >= POld) && "PSet overflow");
+ if (PNew > MOld)
+ MNew = PNew;
+ // Check if current pressure has exceeded the limit.
+ if (!Delta.Excess.isValid()) {
+ unsigned ExcessInc = 0;
+ if (PNew > Limit)
+ ExcessInc = POld > Limit ? PNew - POld : PNew - Limit;
+ else if (POld > Limit)
+ ExcessInc = Limit - POld;
+ if (ExcessInc) {
+ Delta.Excess = PressureChange(PSetID);
+ Delta.Excess.setUnitInc(ExcessInc);
+ }
+ }
+ // Check if max pressure has exceeded a critical pressure set max.
+ if (MNew == MOld)
+ continue;
+ if (!Delta.CriticalMax.isValid()) {
+ while (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() < PSetID)
+ ++CritIdx;
+
+ if (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() == PSetID) {
+ int CritInc = (int)MNew - (int)CriticalPSets[CritIdx].getUnitInc();
+ if (CritInc > 0 && CritInc <= INT16_MAX) {
+ Delta.CriticalMax = PressureChange(PSetID);
+ Delta.CriticalMax.setUnitInc(CritInc);
+ }
+ }
+ }
+ // Check if max pressure has exceeded the current max.
+ if (!Delta.CurrentMax.isValid() && MNew > MaxPressureLimit[PSetID]) {
+ Delta.CurrentMax = PressureChange(PSetID);
+ Delta.CurrentMax.setUnitInc(MNew - MOld);
}
}
- for (unsigned i = 0; i < VirtRegOpers.Defs.size(); ++i) {
- unsigned Reg = VirtRegOpers.Defs[i];
- if (LiveVirtRegs.insert(Reg).second)
- increaseVirtRegPressure(Reg);
+}
+
+/// Helper to find a vreg use between two indices [PriorUseIdx, NextUseIdx).
+static bool findUseBetween(unsigned Reg,
+ SlotIndex PriorUseIdx, SlotIndex NextUseIdx,
+ const MachineRegisterInfo *MRI,
+ const LiveIntervals *LIS) {
+ for (MachineRegisterInfo::use_instr_nodbg_iterator
+ UI = MRI->use_instr_nodbg_begin(Reg),
+ UE = MRI->use_instr_nodbg_end(); UI != UE; ++UI) {
+ const MachineInstr* MI = &*UI;
+ if (MI->isDebugValue())
+ continue;
+ SlotIndex InstSlot = LIS->getInstructionIndex(MI).getRegSlot();
+ if (InstSlot >= PriorUseIdx && InstSlot < NextUseIdx)
+ return true;
}
+ return false;
+}
+
+/// Record the downward impact of a single instruction on current register
+/// pressure. Unlike the advance/recede pressure tracking interface, this does
+/// not discover live in/outs.
+///
+/// This is intended for speculative queries. It leaves pressure inconsistent
+/// with the current position, so must be restored by the caller.
+void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) {
+ assert(!MI->isDebugValue() && "Expect a nondebug instruction.");
+
+ // Account for register pressure similar to RegPressureTracker::recede().
+ RegisterOperands RegOpers(TRI, MRI);
+ collectOperands(MI, RegOpers);
+
+ // Kill liveness at last uses. Assume allocatable physregs are single-use
+ // rather than checking LiveIntervals.
+ SlotIndex SlotIdx;
+ if (RequireIntervals)
+ SlotIdx = LIS->getInstructionIndex(MI).getRegSlot();
+
+ for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) {
+ unsigned Reg = RegOpers.Uses[i];
+ if (RequireIntervals) {
+ // FIXME: allow the caller to pass in the list of vreg uses that remain
+ // to be bottom-scheduled to avoid searching uses at each query.
+ SlotIndex CurrIdx = getCurrSlot();
+ const LiveRange *LR = getLiveRange(Reg);
+ if (LR) {
+ LiveQueryResult LRQ = LR->Query(SlotIdx);
+ if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS)) {
+ decreaseRegPressure(Reg);
+ }
+ }
+ }
+ else if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
+ // Allocatable physregs are always single-use before register rewriting.
+ decreaseRegPressure(Reg);
+ }
+ }
+
+ // Generate liveness for defs.
+ increaseRegPressure(RegOpers.Defs);
// Boost pressure for all dead defs together.
- for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
- increasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
- increaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < PhysRegOpers.DeadDefs.size(); ++i)
- decreasePhysRegPressure(PhysRegOpers.DeadDefs[i]);
- for (unsigned i = 0; i < VirtRegOpers.DeadDefs.size(); ++i)
- decreaseVirtRegPressure(VirtRegOpers.DeadDefs[i]);
+ increaseRegPressure(RegOpers.DeadDefs);
+ decreaseRegPressure(RegOpers.DeadDefs);
+}
- // Find the next instruction.
- while (++CurrPos != MBB->end() && CurrPos->isDebugValue());
- return true;
+/// Consider the pressure increase caused by traversing this instruction
+/// top-down. Find the register class with the most change in its pressure limit
+/// based on the tracker's current pressure, and return the number of excess
+/// register units of that pressure set introduced by this instruction.
+///
+/// This assumes that the current LiveIn set is sufficient.
+///
+/// This is expensive for an on-the-fly query because it calls
+/// bumpDownwardPressure to recompute the pressure sets based on current
+/// liveness. We don't yet have a fast version of downward pressure tracking
+/// analogous to getUpwardPressureDelta.
+void RegPressureTracker::
+getMaxDownwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta,
+ ArrayRef<PressureChange> CriticalPSets,
+ ArrayRef<unsigned> MaxPressureLimit) {
+ // Snapshot Pressure.
+ std::vector<unsigned> SavedPressure = CurrSetPressure;
+ std::vector<unsigned> SavedMaxPressure = P.MaxSetPressure;
+
+ bumpDownwardPressure(MI);
+
+ computeExcessPressureDelta(SavedPressure, CurrSetPressure, Delta, RCI,
+ LiveThruPressure);
+ computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets,
+ MaxPressureLimit, Delta);
+ assert(Delta.CriticalMax.getUnitInc() >= 0 &&
+ Delta.CurrentMax.getUnitInc() >= 0 && "cannot decrease max pressure");
+
+ // Restore the tracker's state.
+ P.MaxSetPressure.swap(SavedMaxPressure);
+ CurrSetPressure.swap(SavedPressure);
+}
+
+/// Get the pressure of each PSet after traversing this instruction bottom-up.
+void RegPressureTracker::
+getUpwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult,
+ std::vector<unsigned> &MaxPressureResult) {
+ // Snapshot pressure.
+ PressureResult = CurrSetPressure;
+ MaxPressureResult = P.MaxSetPressure;
+
+ bumpUpwardPressure(MI);
+
+ // Current pressure becomes the result. Restore current pressure.
+ P.MaxSetPressure.swap(MaxPressureResult);
+ CurrSetPressure.swap(PressureResult);
+}
+
+/// Get the pressure of each PSet after traversing this instruction top-down.
+void RegPressureTracker::
+getDownwardPressure(const MachineInstr *MI,
+ std::vector<unsigned> &PressureResult,
+ std::vector<unsigned> &MaxPressureResult) {
+ // Snapshot pressure.
+ PressureResult = CurrSetPressure;
+ MaxPressureResult = P.MaxSetPressure;
+
+ bumpDownwardPressure(MI);
+
+ // Current pressure becomes the result. Restore current pressure.
+ P.MaxSetPressure.swap(MaxPressureResult);
+ CurrSetPressure.swap(PressureResult);
}
projects / oota-llvm.git / blobdiff