//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "twoaddrinstr"
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "twoaddrinstr"
+
STATISTIC(NumTwoAddressInstrs, "Number of two-address instructions");
STATISTIC(NumCommuted , "Number of instructions commuted to coalesce");
STATISTIC(NumAggrCommuted , "Number of instructions aggressively commuted");
STATISTIC(NumReSchedUps, "Number of instructions re-scheduled up");
STATISTIC(NumReSchedDowns, "Number of instructions re-scheduled down");
+// Temporary flag to disable rescheduling.
+static cl::opt<bool>
+EnableRescheduling("twoaddr-reschedule",
+ cl::desc("Coalesce copies by rescheduling (default=true)"),
+ cl::init(true), cl::Hidden);
+
namespace {
class TwoAddressInstructionPass : public MachineFunctionPass {
MachineFunction *MF;
const InstrItineraryData *InstrItins;
MachineRegisterInfo *MRI;
LiveVariables *LV;
- SlotIndexes *Indexes;
LiveIntervals *LIS;
AliasAnalysis *AA;
CodeGenOpt::Level OptLevel;
bool tryInstructionTransform(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
unsigned SrcIdx, unsigned DstIdx,
- unsigned Dist);
+ unsigned Dist, bool shouldOnlyCommute);
void scanUses(unsigned DstReg);
initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
}
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<AliasAnalysis>();
AU.addPreserved<LiveVariables>();
}
/// runOnMachineFunction - Pass entry point.
- bool runOnMachineFunction(MachineFunction&);
+ bool runOnMachineFunction(MachineFunction&) override;
};
} // end anonymous namespace
char &llvm::TwoAddressInstructionPassID = TwoAddressInstructionPass::ID;
+static bool isPlainlyKilled(MachineInstr *MI, unsigned Reg, LiveIntervals *LIS);
+
/// sink3AddrInstruction - A two-address instruction has been converted to a
/// three-address instruction to avoid clobbering a register. Try to sink it
/// past the instruction that would kill the above mentioned register to reduce
}
// Find the instruction that kills SavedReg.
- MachineInstr *KillMI = NULL;
- for (MachineRegisterInfo::use_nodbg_iterator
- UI = MRI->use_nodbg_begin(SavedReg),
- UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
- MachineOperand &UseMO = UI.getOperand();
- if (!UseMO.isKill())
- continue;
- KillMI = UseMO.getParent();
- break;
+ MachineInstr *KillMI = nullptr;
+ if (LIS) {
+ LiveInterval &LI = LIS->getInterval(SavedReg);
+ assert(LI.end() != LI.begin() &&
+ "Reg should not have empty live interval.");
+
+ SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
+ LiveInterval::const_iterator I = LI.find(MBBEndIdx);
+ if (I != LI.end() && I->start < MBBEndIdx)
+ return false;
+
+ --I;
+ KillMI = LIS->getInstructionFromIndex(I->end);
+ }
+ if (!KillMI) {
+ for (MachineRegisterInfo::use_nodbg_iterator
+ UI = MRI->use_nodbg_begin(SavedReg),
+ UE = MRI->use_nodbg_end(); UI != UE; ++UI) {
+ MachineOperand &UseMO = *UI;
+ if (!UseMO.isKill())
+ continue;
+ KillMI = UseMO.getParent();
+ break;
+ }
}
// If we find the instruction that kills SavedReg, and it is in an
// FIXME: This can be sped up if there is an easy way to query whether an
// instruction is before or after another instruction. Then we can use
// MachineRegisterInfo def / use instead.
- MachineOperand *KillMO = NULL;
+ MachineOperand *KillMO = nullptr;
MachineBasicBlock::iterator KillPos = KillMI;
++KillPos;
unsigned NumVisited = 0;
- for (MachineBasicBlock::iterator I = llvm::next(OldPos); I != KillPos; ++I) {
+ for (MachineBasicBlock::iterator I = std::next(OldPos); I != KillPos; ++I) {
MachineInstr *OtherMI = I;
// DBG_VALUE cannot be counted against the limit.
if (OtherMI->isDebugValue())
if (DefReg == MOReg)
return false;
- if (MO.isKill()) {
+ if (MO.isKill() || (LIS && isPlainlyKilled(OtherMI, MOReg, LIS))) {
if (OtherMI == KillMI && MOReg == SavedReg)
// Save the operand that kills the register. We want to unset the kill
// marker if we can sink MI past it.
}
assert(KillMO && "Didn't find kill");
- // Update kill and LV information.
- KillMO->setIsKill(false);
- KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI);
- KillMO->setIsKill(true);
+ if (!LIS) {
+ // Update kill and LV information.
+ KillMO->setIsKill(false);
+ KillMO = MI->findRegisterUseOperand(SavedReg, false, TRI);
+ KillMO->setIsKill(true);
- if (LV)
- LV->replaceKillInstruction(SavedReg, KillMI, MI);
+ if (LV)
+ LV->replaceKillInstruction(SavedReg, KillMI, MI);
+ }
// Move instruction to its destination.
MBB->remove(MI);
unsigned &LastDef) {
LastDef = 0;
unsigned LastUse = Dist;
- for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(Reg),
- E = MRI->reg_end(); I != E; ++I) {
- MachineOperand &MO = I.getOperand();
+ for (MachineOperand &MO : MRI->reg_operands(Reg)) {
MachineInstr *MI = MO.getParent();
if (MI->getParent() != MBB || MI->isDebugValue())
continue;
return true;
}
+/// isPLainlyKilled - Test if the given register value, which is used by the
+// given instruction, is killed by the given instruction.
+static bool isPlainlyKilled(MachineInstr *MI, unsigned Reg,
+ LiveIntervals *LIS) {
+ if (LIS && TargetRegisterInfo::isVirtualRegister(Reg) &&
+ !LIS->isNotInMIMap(MI)) {
+ // FIXME: Sometimes tryInstructionTransform() will add instructions and
+ // test whether they can be folded before keeping them. In this case it
+ // sets a kill before recursively calling tryInstructionTransform() again.
+ // If there is no interval available, we assume that this instruction is
+ // one of those. A kill flag is manually inserted on the operand so the
+ // check below will handle it.
+ LiveInterval &LI = LIS->getInterval(Reg);
+ // This is to match the kill flag version where undefs don't have kill
+ // flags.
+ if (!LI.hasAtLeastOneValue())
+ return false;
+
+ SlotIndex useIdx = LIS->getInstructionIndex(MI);
+ LiveInterval::const_iterator I = LI.find(useIdx);
+ assert(I != LI.end() && "Reg must be live-in to use.");
+ return !I->end.isBlock() && SlotIndex::isSameInstr(I->end, useIdx);
+ }
+
+ return MI->killsRegister(Reg);
+}
+
/// isKilled - Test if the given register value, which is used by the given
/// instruction, is killed by the given instruction. This looks through
/// coalescable copies to see if the original value is potentially not killed.
/// normal heuristics commute the (two-address) add, which lets
/// coalescing eliminate the extra copy.
///
+/// If allowFalsePositives is true then likely kills are treated as kills even
+/// if it can't be proven that they are kills.
static bool isKilled(MachineInstr &MI, unsigned Reg,
const MachineRegisterInfo *MRI,
- const TargetInstrInfo *TII) {
+ const TargetInstrInfo *TII,
+ LiveIntervals *LIS,
+ bool allowFalsePositives) {
MachineInstr *DefMI = &MI;
for (;;) {
- if (!DefMI->killsRegister(Reg))
+ // All uses of physical registers are likely to be kills.
+ if (TargetRegisterInfo::isPhysicalRegister(Reg) &&
+ (allowFalsePositives || MRI->hasOneUse(Reg)))
+ return true;
+ if (!isPlainlyKilled(DefMI, Reg, LIS))
return false;
if (TargetRegisterInfo::isPhysicalRegister(Reg))
return true;
MachineRegisterInfo::def_iterator Begin = MRI->def_begin(Reg);
// If there are multiple defs, we can't do a simple analysis, so just
// go with what the kill flag says.
- if (llvm::next(Begin) != MRI->def_end())
+ if (std::next(Begin) != MRI->def_end())
return true;
- DefMI = &*Begin;
+ DefMI = Begin->getParent();
bool IsSrcPhys, IsDstPhys;
unsigned SrcReg, DstReg;
// If the def is something other than a copy, then it isn't going to
/// isTwoAddrUse - Return true if the specified MI uses the specified register
/// as a two-address use. If so, return the destination register by reference.
static bool isTwoAddrUse(MachineInstr &MI, unsigned Reg, unsigned &DstReg) {
- const MCInstrDesc &MCID = MI.getDesc();
- unsigned NumOps = MI.isInlineAsm()
- ? MI.getNumOperands() : MCID.getNumOperands();
- for (unsigned i = 0; i != NumOps; ++i) {
+ for (unsigned i = 0, NumOps = MI.getNumOperands(); i != NumOps; ++i) {
const MachineOperand &MO = MI.getOperand(i);
if (!MO.isReg() || !MO.isUse() || MO.getReg() != Reg)
continue;
unsigned &DstReg, bool &IsDstPhys) {
if (!MRI->hasOneNonDBGUse(Reg))
// None or more than one use.
- return 0;
- MachineInstr &UseMI = *MRI->use_nodbg_begin(Reg);
+ return nullptr;
+ MachineInstr &UseMI = *MRI->use_instr_nodbg_begin(Reg);
if (UseMI.getParent() != MBB)
- return 0;
+ return nullptr;
unsigned SrcReg;
bool IsSrcPhys;
if (isCopyToReg(UseMI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys)) {
IsDstPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
return &UseMI;
}
- return 0;
+ return nullptr;
}
/// getMappedReg - Return the physical register the specified virtual register
// insert => %reg1030<def> = MOV8rr %reg1029
// %reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>
- if (!MI->killsRegister(regC))
+ if (!isPlainlyKilled(MI, regC, LIS))
return false;
// Ok, we have something like:
DEBUG(dbgs() << "2addr: COMMUTING : " << *MI);
MachineInstr *NewMI = TII->commuteInstruction(MI);
- if (NewMI == 0) {
+ if (NewMI == nullptr) {
DEBUG(dbgs() << "2addr: COMMUTING FAILED!\n");
return false;
}
DEBUG(dbgs() << "2addr: COMMUTED TO: " << *NewMI);
- // If the instruction changed to commute it, update livevar.
- if (NewMI != MI) {
- if (LV)
- // Update live variables
- LV->replaceKillInstruction(RegC, MI, NewMI);
- if (Indexes)
- Indexes->replaceMachineInstrInMaps(MI, NewMI);
-
- MBB->insert(mi, NewMI); // Insert the new inst
- MBB->erase(mi); // Nuke the old inst.
- mi = NewMI;
- DistanceMap.insert(std::make_pair(NewMI, Dist));
- }
+ assert(NewMI == MI &&
+ "TargetInstrInfo::commuteInstruction() should not return a new "
+ "instruction unless it was requested.");
// Update source register map.
unsigned FromRegC = getMappedReg(RegC, SrcRegMap);
DEBUG(dbgs() << "2addr: TO 3-ADDR: " << *NewMI);
bool Sunk = false;
- if (Indexes)
- Indexes->replaceMachineInstrInMaps(mi, NewMI);
+ if (LIS)
+ LIS->ReplaceMachineInstrInMaps(mi, NewMI);
if (NewMI->findRegisterUseOperand(RegB, false, TRI))
// FIXME: Temporary workaround. If the new instruction doesn't
if (!Sunk) {
DistanceMap.insert(std::make_pair(NewMI, Dist));
mi = NewMI;
- nmi = llvm::next(mi);
+ nmi = std::next(mi);
}
// Update source and destination register maps.
rescheduleMIBelowKill(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
unsigned Reg) {
- // Bail immediately if we don't have LV available. We use it to find kills
- // efficiently.
- if (!LV)
+ // Bail immediately if we don't have LV or LIS available. We use them to find
+ // kills efficiently.
+ if (!LV && !LIS)
return false;
MachineInstr *MI = &*mi;
// Must be created from unfolded load. Don't waste time trying this.
return false;
- MachineInstr *KillMI = LV->getVarInfo(Reg).findKill(MBB);
+ MachineInstr *KillMI = nullptr;
+ if (LIS) {
+ LiveInterval &LI = LIS->getInterval(Reg);
+ assert(LI.end() != LI.begin() &&
+ "Reg should not have empty live interval.");
+
+ SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
+ LiveInterval::const_iterator I = LI.find(MBBEndIdx);
+ if (I != LI.end() && I->start < MBBEndIdx)
+ return false;
+
+ --I;
+ KillMI = LIS->getInstructionFromIndex(I->end);
+ } else {
+ KillMI = LV->getVarInfo(Reg).findKill(MBB);
+ }
if (!KillMI || MI == KillMI || KillMI->isCopy() || KillMI->isCopyLike())
// Don't mess with copies, they may be coalesced later.
return false;
Defs.insert(MOReg);
else {
Uses.insert(MOReg);
- if (MO.isKill() && MOReg != Reg)
+ if (MOReg != Reg && (MO.isKill() ||
+ (LIS && isPlainlyKilled(MI, MOReg, LIS))))
Kills.insert(MOReg);
}
}
// Move the copies connected to MI down as well.
- MachineBasicBlock::iterator From = MI;
- MachineBasicBlock::iterator To = llvm::next(From);
- while (To->isCopy() && Defs.count(To->getOperand(1).getReg())) {
- Defs.insert(To->getOperand(0).getReg());
- ++To;
+ MachineBasicBlock::iterator Begin = MI;
+ MachineBasicBlock::iterator AfterMI = std::next(Begin);
+
+ MachineBasicBlock::iterator End = AfterMI;
+ while (End->isCopy() && Defs.count(End->getOperand(1).getReg())) {
+ Defs.insert(End->getOperand(0).getReg());
+ ++End;
}
// Check if the reschedule will not break depedencies.
unsigned NumVisited = 0;
MachineBasicBlock::iterator KillPos = KillMI;
++KillPos;
- for (MachineBasicBlock::iterator I = To; I != KillPos; ++I) {
+ for (MachineBasicBlock::iterator I = End; I != KillPos; ++I) {
MachineInstr *OtherMI = I;
// DBG_VALUE cannot be counted against the limit.
if (OtherMI->isDebugValue())
} else {
if (Defs.count(MOReg))
return false;
+ bool isKill = MO.isKill() ||
+ (LIS && isPlainlyKilled(OtherMI, MOReg, LIS));
if (MOReg != Reg &&
- ((MO.isKill() && Uses.count(MOReg)) || Kills.count(MOReg)))
+ ((isKill && Uses.count(MOReg)) || Kills.count(MOReg)))
// Don't want to extend other live ranges and update kills.
return false;
- if (MOReg == Reg && !MO.isKill())
+ if (MOReg == Reg && !isKill)
// We can't schedule across a use of the register in question.
return false;
// Ensure that if this is register in question, its the kill we expect.
}
// Move debug info as well.
- while (From != MBB->begin() && llvm::prior(From)->isDebugValue())
- --From;
+ while (Begin != MBB->begin() && std::prev(Begin)->isDebugValue())
+ --Begin;
+
+ nmi = End;
+ MachineBasicBlock::iterator InsertPos = KillPos;
+ if (LIS) {
+ // We have to move the copies first so that the MBB is still well-formed
+ // when calling handleMove().
+ for (MachineBasicBlock::iterator MBBI = AfterMI; MBBI != End;) {
+ MachineInstr *CopyMI = MBBI;
+ ++MBBI;
+ MBB->splice(InsertPos, MBB, CopyMI);
+ LIS->handleMove(CopyMI);
+ InsertPos = CopyMI;
+ }
+ End = std::next(MachineBasicBlock::iterator(MI));
+ }
// Copies following MI may have been moved as well.
- nmi = To;
- MBB->splice(KillPos, MBB, From, To);
+ MBB->splice(InsertPos, MBB, Begin, End);
DistanceMap.erase(DI);
// Update live variables
- LV->removeVirtualRegisterKilled(Reg, KillMI);
- LV->addVirtualRegisterKilled(Reg, MI);
- if (LIS)
+ if (LIS) {
LIS->handleMove(MI);
+ } else {
+ LV->removeVirtualRegisterKilled(Reg, KillMI);
+ LV->addVirtualRegisterKilled(Reg, MI);
+ }
DEBUG(dbgs() << "\trescheduled below kill: " << *KillMI);
return true;
/// instruction too close to the defs of its register dependencies.
bool TwoAddressInstructionPass::isDefTooClose(unsigned Reg, unsigned Dist,
MachineInstr *MI) {
- for (MachineRegisterInfo::def_iterator DI = MRI->def_begin(Reg),
- DE = MRI->def_end(); DI != DE; ++DI) {
- MachineInstr *DefMI = &*DI;
- if (DefMI->getParent() != MBB || DefMI->isCopy() || DefMI->isCopyLike())
+ for (MachineInstr &DefMI : MRI->def_instructions(Reg)) {
+ if (DefMI.getParent() != MBB || DefMI.isCopy() || DefMI.isCopyLike())
continue;
- if (DefMI == MI)
+ if (&DefMI == MI)
return true; // MI is defining something KillMI uses
- DenseMap<MachineInstr*, unsigned>::iterator DDI = DistanceMap.find(DefMI);
+ DenseMap<MachineInstr*, unsigned>::iterator DDI = DistanceMap.find(&DefMI);
if (DDI == DistanceMap.end())
return true; // Below MI
unsigned DefDist = DDI->second;
assert(Dist > DefDist && "Visited def already?");
- if (TII->getInstrLatency(InstrItins, DefMI) > (Dist - DefDist))
+ if (TII->getInstrLatency(InstrItins, &DefMI) > (Dist - DefDist))
return true;
}
return false;
rescheduleKillAboveMI(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
unsigned Reg) {
- // Bail immediately if we don't have LV available. We use it to find kills
- // efficiently.
- if (!LV)
+ // Bail immediately if we don't have LV or LIS available. We use them to find
+ // kills efficiently.
+ if (!LV && !LIS)
return false;
MachineInstr *MI = &*mi;
// Must be created from unfolded load. Don't waste time trying this.
return false;
- MachineInstr *KillMI = LV->getVarInfo(Reg).findKill(MBB);
+ MachineInstr *KillMI = nullptr;
+ if (LIS) {
+ LiveInterval &LI = LIS->getInterval(Reg);
+ assert(LI.end() != LI.begin() &&
+ "Reg should not have empty live interval.");
+
+ SlotIndex MBBEndIdx = LIS->getMBBEndIdx(MBB).getPrevSlot();
+ LiveInterval::const_iterator I = LI.find(MBBEndIdx);
+ if (I != LI.end() && I->start < MBBEndIdx)
+ return false;
+
+ --I;
+ KillMI = LIS->getInstructionFromIndex(I->end);
+ } else {
+ KillMI = LV->getVarInfo(Reg).findKill(MBB);
+ }
if (!KillMI || MI == KillMI || KillMI->isCopy() || KillMI->isCopyLike())
// Don't mess with copies, they may be coalesced later.
return false;
continue;
if (isDefTooClose(MOReg, DI->second, MI))
return false;
- if (MOReg == Reg && !MO.isKill())
+ bool isKill = MO.isKill() || (LIS && isPlainlyKilled(KillMI, MOReg, LIS));
+ if (MOReg == Reg && !isKill)
return false;
Uses.insert(MOReg);
- if (MO.isKill() && MOReg != Reg)
+ if (isKill && MOReg != Reg)
Kills.insert(MOReg);
} else if (TargetRegisterInfo::isPhysicalRegister(MOReg)) {
Defs.insert(MOReg);
if (Kills.count(MOReg))
// Don't want to extend other live ranges and update kills.
return false;
- if (OtherMI != MI && MOReg == Reg && !MO.isKill())
+ if (OtherMI != MI && MOReg == Reg &&
+ !(MO.isKill() || (LIS && isPlainlyKilled(OtherMI, MOReg, LIS))))
// We can't schedule across a use of the register in question.
return false;
} else {
// Move the old kill above MI, don't forget to move debug info as well.
MachineBasicBlock::iterator InsertPos = mi;
- while (InsertPos != MBB->begin() && llvm::prior(InsertPos)->isDebugValue())
+ while (InsertPos != MBB->begin() && std::prev(InsertPos)->isDebugValue())
--InsertPos;
MachineBasicBlock::iterator From = KillMI;
- MachineBasicBlock::iterator To = llvm::next(From);
- while (llvm::prior(From)->isDebugValue())
+ MachineBasicBlock::iterator To = std::next(From);
+ while (std::prev(From)->isDebugValue())
--From;
MBB->splice(InsertPos, MBB, From, To);
- nmi = llvm::prior(InsertPos); // Backtrack so we process the moved instr.
+ nmi = std::prev(InsertPos); // Backtrack so we process the moved instr.
DistanceMap.erase(DI);
// Update live variables
- LV->removeVirtualRegisterKilled(Reg, KillMI);
- LV->addVirtualRegisterKilled(Reg, MI);
- if (LIS)
+ if (LIS) {
LIS->handleMove(KillMI);
+ } else {
+ LV->removeVirtualRegisterKilled(Reg, KillMI);
+ LV->addVirtualRegisterKilled(Reg, MI);
+ }
DEBUG(dbgs() << "\trescheduled kill: " << *KillMI);
return true;
/// either eliminate the tied operands or improve the opportunities for
/// coalescing away the register copy. Returns true if no copy needs to be
/// inserted to untie mi's operands (either because they were untied, or
-/// because mi was rescheduled, and will be visited again later).
+/// because mi was rescheduled, and will be visited again later). If the
+/// shouldOnlyCommute flag is true, only instruction commutation is attempted.
bool TwoAddressInstructionPass::
tryInstructionTransform(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
- unsigned SrcIdx, unsigned DstIdx, unsigned Dist) {
+ unsigned SrcIdx, unsigned DstIdx,
+ unsigned Dist, bool shouldOnlyCommute) {
if (OptLevel == CodeGenOpt::None)
return false;
assert(TargetRegisterInfo::isVirtualRegister(regB) &&
"cannot make instruction into two-address form");
- bool regBKilled = isKilled(MI, regB, MRI, TII);
+ bool regBKilled = isKilled(MI, regB, MRI, TII, LIS, true);
if (TargetRegisterInfo::isVirtualRegister(regA))
scanUses(regA);
if (regCIdx != ~0U) {
regC = MI.getOperand(regCIdx).getReg();
- if (!regBKilled && isKilled(MI, regC, MRI, TII))
+ if (!regBKilled && isKilled(MI, regC, MRI, TII, LIS, false))
// If C dies but B does not, swap the B and C operands.
// This makes the live ranges of A and C joinable.
TryCommute = true;
return false;
}
+ if (shouldOnlyCommute)
+ return false;
+
// If there is one more use of regB later in the same MBB, consider
// re-schedule this MI below it.
- if (rescheduleMIBelowKill(mi, nmi, regB)) {
+ if (EnableRescheduling && rescheduleMIBelowKill(mi, nmi, regB)) {
++NumReSchedDowns;
return true;
}
// If there is one more use of regB later in the same MBB, consider
// re-schedule it before this MI if it's legal.
- if (rescheduleKillAboveMI(mi, nmi, regB)) {
+ if (EnableRescheduling && rescheduleKillAboveMI(mi, nmi, regB)) {
++NumReSchedUps;
return true;
}
unsigned NewDstIdx = NewMIs[1]->findRegisterDefOperandIdx(regA);
unsigned NewSrcIdx = NewMIs[1]->findRegisterUseOperandIdx(regB);
MachineBasicBlock::iterator NewMI = NewMIs[1];
- bool TransformSuccess =
- tryInstructionTransform(NewMI, mi, NewSrcIdx, NewDstIdx, Dist);
- if (TransformSuccess ||
- NewMIs[1]->getOperand(NewSrcIdx).isKill()) {
+ bool TransformResult =
+ tryInstructionTransform(NewMI, mi, NewSrcIdx, NewDstIdx, Dist, true);
+ (void)TransformResult;
+ assert(!TransformResult &&
+ "tryInstructionTransform() should return false.");
+ if (NewMIs[1]->getOperand(NewSrcIdx).isKill()) {
// Success, or at least we made an improvement. Keep the unfolded
// instructions and discard the original.
if (LV) {
}
mi = NewMIs[1];
- if (TransformSuccess)
- return true;
} else {
// Transforming didn't eliminate the tie and didn't lead to an
// improvement. Clean up the unfolded instructions and keep the
assert(SrcReg && SrcMO.isUse() && "two address instruction invalid");
// Deal with <undef> uses immediately - simply rewrite the src operand.
- if (SrcMO.isUndef()) {
+ if (SrcMO.isUndef() && !DstMO.getSubReg()) {
// Constrain the DstReg register class if required.
if (TargetRegisterInfo::isVirtualRegister(DstReg))
if (const TargetRegisterClass *RC = TII->getRegClass(MCID, SrcIdx,
TRI, *MF))
MRI->constrainRegClass(DstReg, RC);
SrcMO.setReg(DstReg);
+ SrcMO.setSubReg(0);
DEBUG(dbgs() << "\t\trewrite undef:\t" << *MI);
continue;
}
unsigned LastCopiedReg = 0;
SlotIndex LastCopyIdx;
unsigned RegB = 0;
+ unsigned SubRegB = 0;
for (unsigned tpi = 0, tpe = TiedPairs.size(); tpi != tpe; ++tpi) {
unsigned SrcIdx = TiedPairs[tpi].first;
unsigned DstIdx = TiedPairs[tpi].second;
// Grab RegB from the instruction because it may have changed if the
// instruction was commuted.
RegB = MI->getOperand(SrcIdx).getReg();
+ SubRegB = MI->getOperand(SrcIdx).getSubReg();
if (RegA == RegB) {
// The register is tied to multiple destinations (or else we would
#endif
// Emit a copy.
- BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
- TII->get(TargetOpcode::COPY), RegA).addReg(RegB);
+ MachineInstrBuilder MIB = BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
+ TII->get(TargetOpcode::COPY), RegA);
+ // If this operand is folding a truncation, the truncation now moves to the
+ // copy so that the register classes remain valid for the operands.
+ MIB.addReg(RegB, 0, SubRegB);
+ const TargetRegisterClass *RC = MRI->getRegClass(RegB);
+ if (SubRegB) {
+ if (TargetRegisterInfo::isVirtualRegister(RegA)) {
+ assert(TRI->getMatchingSuperRegClass(RC, MRI->getRegClass(RegA),
+ SubRegB) &&
+ "tied subregister must be a truncation");
+ // The superreg class will not be used to constrain the subreg class.
+ RC = nullptr;
+ }
+ else {
+ assert(TRI->getMatchingSuperReg(RegA, SubRegB, MRI->getRegClass(RegB))
+ && "tied subregister must be a truncation");
+ }
+ }
// Update DistanceMap.
MachineBasicBlock::iterator PrevMI = MI;
VNInfo *VNI = LI.getNextValue(LastCopyIdx, LIS->getVNInfoAllocator());
SlotIndex endIdx =
LIS->getInstructionIndex(MI).getRegSlot(IsEarlyClobber);
- LI.addRange(LiveRange(LastCopyIdx, endIdx, VNI));
+ LI.addSegment(LiveInterval::Segment(LastCopyIdx, endIdx, VNI));
}
}
- DEBUG(dbgs() << "\t\tprepend:\t" << *PrevMI);
+ DEBUG(dbgs() << "\t\tprepend:\t" << *MIB);
MachineOperand &MO = MI->getOperand(SrcIdx);
assert(MO.isReg() && MO.getReg() == RegB && MO.isUse() &&
// Make sure regA is a legal regclass for the SrcIdx operand.
if (TargetRegisterInfo::isVirtualRegister(RegA) &&
TargetRegisterInfo::isVirtualRegister(RegB))
- MRI->constrainRegClass(RegA, MRI->getRegClass(RegB));
-
+ MRI->constrainRegClass(RegA, RC);
MO.setReg(RegA);
+ // The getMatchingSuper asserts guarantee that the register class projected
+ // by SubRegB is compatible with RegA with no subregister. So regardless of
+ // whether the dest oper writes a subreg, the source oper should not.
+ MO.setSubReg(0);
// Propagate SrcRegMap.
SrcRegMap[RegA] = RegB;
// Replace other (un-tied) uses of regB with LastCopiedReg.
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.getReg() == RegB && MO.isUse()) {
+ if (MO.isReg() && MO.getReg() == RegB && MO.getSubReg() == SubRegB &&
+ MO.isUse()) {
if (MO.isKill()) {
MO.setIsKill(false);
RemovedKillFlag = true;
}
MO.setReg(LastCopiedReg);
+ MO.setSubReg(0);
}
}
}
SlotIndex UseIdx = MIIdx.getRegSlot(IsEarlyClobber);
if (I->end == UseIdx)
- LI.removeRange(LastCopyIdx, UseIdx);
+ LI.removeSegment(LastCopyIdx, UseIdx);
}
} else if (RemovedKillFlag) {
TII = TM.getInstrInfo();
TRI = TM.getRegisterInfo();
InstrItins = TM.getInstrItineraryData();
- Indexes = getAnalysisIfAvailable<SlotIndexes>();
LV = getAnalysisIfAvailable<LiveVariables>();
LIS = getAnalysisIfAvailable<LiveIntervals>();
AA = &getAnalysis<AliasAnalysis>();
Processed.clear();
for (MachineBasicBlock::iterator mi = MBB->begin(), me = MBB->end();
mi != me; ) {
- MachineBasicBlock::iterator nmi = llvm::next(mi);
+ MachineBasicBlock::iterator nmi = std::next(mi);
if (mi->isDebugValue()) {
mi = nmi;
continue;
// transformations that may either eliminate the tied operands or
// improve the opportunities for coalescing away the register copy.
if (TiedOperands.size() == 1) {
- SmallVector<std::pair<unsigned, unsigned>, 4> &TiedPairs
+ SmallVectorImpl<std::pair<unsigned, unsigned> > &TiedPairs
= TiedOperands.begin()->second;
if (TiedPairs.size() == 1) {
unsigned SrcIdx = TiedPairs[0].first;
unsigned SrcReg = mi->getOperand(SrcIdx).getReg();
unsigned DstReg = mi->getOperand(DstIdx).getReg();
if (SrcReg != DstReg &&
- tryInstructionTransform(mi, nmi, SrcIdx, DstIdx, Dist)) {
+ tryInstructionTransform(mi, nmi, SrcIdx, DstIdx, Dist, false)) {
// The tied operands have been eliminated or shifted further down the
// block to ease elimination. Continue processing with 'nmi'.
TiedOperands.clear();
TargetRegisterInfo::isPhysicalRegister(DstReg) ||
!(MI->getNumOperands() & 1)) {
DEBUG(dbgs() << "Illegal REG_SEQUENCE instruction:" << *MI);
- llvm_unreachable(0);
+ llvm_unreachable(nullptr);
}
SmallVector<unsigned, 4> OrigRegs;
}
MachineBasicBlock::iterator EndMBBI =
- llvm::next(MachineBasicBlock::iterator(MI));
+ std::next(MachineBasicBlock::iterator(MI));
if (!DefEmitted) {
DEBUG(dbgs() << "Turned: " << *MI << " into an IMPLICIT_DEF");
projects / oota-llvm.git / blobdiff