#include "VirtRegMap.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/Value.h"
-#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/RegisterCoalescer.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/SmallSet.h"
using namespace llvm;
STATISTIC(numJoins , "Number of interval joins performed");
+STATISTIC(numCrossRCs , "Number of cross class joins performed");
STATISTIC(numCommutes , "Number of instruction commuting performed");
STATISTIC(numExtends , "Number of copies extended");
+STATISTIC(NumReMats , "Number of instructions re-materialized");
STATISTIC(numPeep , "Number of identity moves eliminated after coalescing");
STATISTIC(numAborts , "Number of times interval joining aborted");
+STATISTIC(numDeadValNo, "Number of valno def marked dead");
char SimpleRegisterCoalescing::ID = 0;
-namespace {
- static cl::opt<bool>
- EnableJoining("join-liveintervals",
- cl::desc("Coalesce copies (default=true)"),
- cl::init(true));
+static cl::opt<bool>
+EnableJoining("join-liveintervals",
+ cl::desc("Coalesce copies (default=true)"),
+ cl::init(true));
- static cl::opt<bool>
- NewHeuristic("new-coalescer-heuristic",
- cl::desc("Use new coalescer heuristic"),
- cl::init(false));
+static cl::opt<bool>
+NewHeuristic("new-coalescer-heuristic",
+ cl::desc("Use new coalescer heuristic"),
+ cl::init(false), cl::Hidden);
- RegisterPass<SimpleRegisterCoalescing>
- X("simple-register-coalescing", "Simple Register Coalescing");
+static cl::opt<bool>
+CrossClassJoin("join-cross-class-copies",
+ cl::desc("Coalesce cross register class copies"),
+ cl::init(false), cl::Hidden);
- // Declare that we implement the RegisterCoalescer interface
- RegisterAnalysisGroup<RegisterCoalescer, true/*The Default*/> V(X);
-}
+static cl::opt<bool>
+PhysJoinTweak("tweak-phys-join-heuristics",
+ cl::desc("Tweak heuristics for joining phys reg with vr"),
+ cl::init(false), cl::Hidden);
+
+static RegisterPass<SimpleRegisterCoalescing>
+X("simple-register-coalescing", "Simple Register Coalescing");
+
+// Declare that we implement the RegisterCoalescer interface
+static RegisterAnalysisGroup<RegisterCoalescer, true/*The Default*/> V(X);
-const PassInfo *llvm::SimpleRegisterCoalescingID = X.getPassInfo();
+const PassInfo *const llvm::SimpleRegisterCoalescingID = &X;
void SimpleRegisterCoalescing::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
+ AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
AU.addPreservedID(MachineDominatorsID);
- AU.addPreservedID(PHIEliminationID);
+ if (StrongPHIElim)
+ AU.addPreservedID(StrongPHIEliminationID);
+ else
+ AU.addPreservedID(PHIEliminationID);
AU.addPreservedID(TwoAddressInstructionPassID);
- AU.addRequired<LiveVariables>();
- AU.addRequired<LiveIntervals>();
- AU.addRequired<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
// BValNo is a value number in B that is defined by a copy from A. 'B3' in
// the example above.
LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx);
- if (BLR == IntB.end()) // Should never happen!
- return false;
+ assert(BLR != IntB.end() && "Live range not found!");
VNInfo *BValNo = BLR->valno;
// Get the location that B is defined at. Two options: either this value has
// AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
- if (ALR == IntA.end()) // Should never happen!
- return false;
+ assert(ALR != IntA.end() && "Live range not found!");
VNInfo *AValNo = ALR->valno;
+ // If it's re-defined by an early clobber somewhere in the live range, then
+ // it's not safe to eliminate the copy. FIXME: This is a temporary workaround.
+ // See PR3149:
+ // 172 %ECX<def> = MOV32rr %reg1039<kill>
+ // 180 INLINEASM <es:subl $5,$1
+ // sbbl $3,$0>, 10, %EAX<def>, 14, %ECX<earlyclobber,def>, 9, %EAX<kill>,
+ // 36, <fi#0>, 1, %reg0, 0, 9, %ECX<kill>, 36, <fi#1>, 1, %reg0, 0
+ // 188 %EAX<def> = MOV32rr %EAX<kill>
+ // 196 %ECX<def> = MOV32rr %ECX<kill>
+ // 204 %ECX<def> = MOV32rr %ECX<kill>
+ // 212 %EAX<def> = MOV32rr %EAX<kill>
+ // 220 %EAX<def> = MOV32rr %EAX
+ // 228 %reg1039<def> = MOV32rr %ECX<kill>
+ // The early clobber operand ties ECX input to the ECX def.
+ //
+ // The live interval of ECX is represented as this:
+ // %reg20,inf = [46,47:1)[174,230:0) 0@174-(230) 1@46-(47)
+ // The coalescer has no idea there was a def in the middle of [174,230].
+ if (AValNo->hasRedefByEC())
+ return false;
// If AValNo is defined as a copy from IntB, we can potentially process this.
// Get the instruction that defines this value number.
// Get the LiveRange in IntB that this value number starts with.
LiveInterval::iterator ValLR = IntB.FindLiveRangeContaining(AValNo->def-1);
- if (ValLR == IntB.end()) // Should never happen!
- return false;
+ assert(ValLR != IntB.end() && "Live range not found!");
// Make sure that the end of the live range is inside the same block as
// CopyMI.
IntB.addRange(LiveRange(FillerStart, FillerEnd, BValNo));
// If the IntB live range is assigned to a physical register, and if that
- // physreg has aliases,
+ // physreg has sub-registers, update their live intervals as well.
if (TargetRegisterInfo::isPhysicalRegister(IntB.reg)) {
- // Update the liveintervals of sub-registers.
- for (const unsigned *AS = tri_->getSubRegisters(IntB.reg); *AS; ++AS) {
- LiveInterval &AliasLI = li_->getInterval(*AS);
- AliasLI.addRange(LiveRange(FillerStart, FillerEnd,
- AliasLI.getNextValue(FillerStart, 0, li_->getVNInfoAllocator())));
+ for (const unsigned *SR = tri_->getSubRegisters(IntB.reg); *SR; ++SR) {
+ LiveInterval &SRLI = li_->getInterval(*SR);
+ SRLI.addRange(LiveRange(FillerStart, FillerEnd,
+ SRLI.getNextValue(FillerStart, 0, true,
+ li_->getVNInfoAllocator())));
}
}
// Okay, merge "B1" into the same value number as "B0".
- if (BValNo != ValLR->valno)
+ if (BValNo != ValLR->valno) {
+ IntB.addKills(ValLR->valno, BValNo->kills);
IntB.MergeValueNumberInto(BValNo, ValLR->valno);
+ }
DOUT << " result = "; IntB.print(DOUT, tri_);
DOUT << "\n";
// If the source instruction was killing the source register before the
// merge, unset the isKill marker given the live range has been extended.
int UIdx = ValLREndInst->findRegisterUseOperandIdx(IntB.reg, true);
- if (UIdx != -1)
+ if (UIdx != -1) {
ValLREndInst->getOperand(UIdx).setIsKill(false);
+ IntB.removeKill(ValLR->valno, FillerStart);
+ }
++numExtends;
return true;
// BValNo is a value number in B that is defined by a copy from A. 'B3' in
// the example above.
LiveInterval::iterator BLR = IntB.FindLiveRangeContaining(CopyIdx);
- if (BLR == IntB.end()) // Should never happen!
- return false;
+ assert(BLR != IntB.end() && "Live range not found!");
VNInfo *BValNo = BLR->valno;
// Get the location that B is defined at. Two options: either this value has
// AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
- if (ALR == IntA.end()) // Should never happen!
- return false;
+ assert(ALR != IntA.end() && "Live range not found!");
VNInfo *AValNo = ALR->valno;
// If other defs can reach uses of this def, then it's not safe to perform
- // the optimization.
- if (AValNo->def == ~0U || AValNo->def == ~1U || AValNo->hasPHIKill)
+ // the optimization. FIXME: Do isPHIDef and isDefAccurate both need to be
+ // tested?
+ if (AValNo->isPHIDef() || !AValNo->isDefAccurate() ||
+ AValNo->isUnused() || AValNo->hasPHIKill())
return false;
MachineInstr *DefMI = li_->getInstructionFromIndex(AValNo->def);
const TargetInstrDesc &TID = DefMI->getDesc();
- unsigned NewDstIdx;
- if (!TID.isCommutable() ||
- !tii_->CommuteChangesDestination(DefMI, NewDstIdx))
+ if (!TID.isCommutable())
+ return false;
+ // If DefMI is a two-address instruction then commuting it will change the
+ // destination register.
+ int DefIdx = DefMI->findRegisterDefOperandIdx(IntA.reg);
+ assert(DefIdx != -1);
+ unsigned UseOpIdx;
+ if (!DefMI->isRegTiedToUseOperand(DefIdx, &UseOpIdx))
+ return false;
+ unsigned Op1, Op2, NewDstIdx;
+ if (!tii_->findCommutedOpIndices(DefMI, Op1, Op2))
+ return false;
+ if (Op1 == UseOpIdx)
+ NewDstIdx = Op2;
+ else if (Op2 == UseOpIdx)
+ NewDstIdx = Op1;
+ else
return false;
MachineOperand &NewDstMO = DefMI->getOperand(NewDstIdx);
unsigned OpIdx = NewMI->findRegisterUseOperandIdx(IntA.reg, false);
NewMI->getOperand(OpIdx).setIsKill();
- bool BHasPHIKill = BValNo->hasPHIKill;
+ bool BHasPHIKill = BValNo->hasPHIKill();
SmallVector<VNInfo*, 4> BDeadValNos;
- SmallVector<unsigned, 4> BKills;
+ VNInfo::KillSet BKills;
std::map<unsigned, unsigned> BExtend;
// If ALR and BLR overlaps and end of BLR extends beyond end of ALR, e.g.
BExtend[ALR->end] = BLR->end;
// Update uses of IntA of the specific Val# with IntB.
+ bool BHasSubRegs = false;
+ if (TargetRegisterInfo::isPhysicalRegister(IntB.reg))
+ BHasSubRegs = *tri_->getSubRegisters(IntB.reg);
for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(IntA.reg),
UE = mri_->use_end(); UI != UE;) {
MachineOperand &UseMO = UI.getOperand();
if (Extended)
UseMO.setIsKill(false);
else
- BKills.push_back(li_->getUseIndex(UseIdx)+1);
+ BKills.push_back(VNInfo::KillInfo(false, li_->getUseIndex(UseIdx)+1));
}
- unsigned SrcReg, DstReg;
- if (!tii_->isMoveInstr(*UseMI, SrcReg, DstReg))
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (!tii_->isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx))
continue;
if (DstReg == IntB.reg) {
// This copy will become a noop. If it's defining a new val#,
// extended to the end of the existing live range defined by the copy.
unsigned DefIdx = li_->getDefIndex(UseIdx);
const LiveRange *DLR = IntB.getLiveRangeContaining(DefIdx);
- BHasPHIKill |= DLR->valno->hasPHIKill;
+ BHasPHIKill |= DLR->valno->hasPHIKill();
assert(DLR->valno->def == DefIdx);
BDeadValNos.push_back(DLR->valno);
BExtend[DLR->start] = DLR->end;
// simply extend BLR if CopyMI doesn't end the range.
DOUT << "\nExtending: "; IntB.print(DOUT, tri_);
- IntB.removeValNo(BValNo);
- for (unsigned i = 0, e = BDeadValNos.size(); i != e; ++i)
+ // Remove val#'s defined by copies that will be coalesced away.
+ for (unsigned i = 0, e = BDeadValNos.size(); i != e; ++i) {
+ VNInfo *DeadVNI = BDeadValNos[i];
+ if (BHasSubRegs) {
+ for (const unsigned *SR = tri_->getSubRegisters(IntB.reg); *SR; ++SR) {
+ LiveInterval &SRLI = li_->getInterval(*SR);
+ const LiveRange *SRLR = SRLI.getLiveRangeContaining(DeadVNI->def);
+ SRLI.removeValNo(SRLR->valno);
+ }
+ }
IntB.removeValNo(BDeadValNos[i]);
- VNInfo *ValNo = IntB.getNextValue(AValNo->def, 0, li_->getVNInfoAllocator());
+ }
+
+ // Extend BValNo by merging in IntA live ranges of AValNo. Val# definition
+ // is updated. Kills are also updated.
+ VNInfo *ValNo = BValNo;
+ ValNo->def = AValNo->def;
+ ValNo->copy = NULL;
+ for (unsigned j = 0, ee = ValNo->kills.size(); j != ee; ++j) {
+ unsigned Kill = ValNo->kills[j].killIdx;
+ if (Kill != BLR->end)
+ BKills.push_back(VNInfo::KillInfo(ValNo->kills[j].isPHIKill, Kill));
+ }
+ ValNo->kills.clear();
for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end();
AI != AE; ++AI) {
if (AI->valno != AValNo) continue;
if (EI != BExtend.end())
End = EI->second;
IntB.addRange(LiveRange(AI->start, End, ValNo));
+
+ // If the IntB live range is assigned to a physical register, and if that
+ // physreg has sub-registers, update their live intervals as well.
+ if (BHasSubRegs) {
+ for (const unsigned *SR = tri_->getSubRegisters(IntB.reg); *SR; ++SR) {
+ LiveInterval &SRLI = li_->getInterval(*SR);
+ SRLI.MergeInClobberRange(AI->start, End, li_->getVNInfoAllocator());
+ }
+ }
}
IntB.addKills(ValNo, BKills);
- ValNo->hasPHIKill = BHasPHIKill;
+ ValNo->setHasPHIKill(BHasPHIKill);
DOUT << " result = "; IntB.print(DOUT, tri_);
DOUT << "\n";
return true;
}
+/// isSameOrFallThroughBB - Return true if MBB == SuccMBB or MBB simply
+/// fallthoughs to SuccMBB.
+static bool isSameOrFallThroughBB(MachineBasicBlock *MBB,
+ MachineBasicBlock *SuccMBB,
+ const TargetInstrInfo *tii_) {
+ if (MBB == SuccMBB)
+ return true;
+ MachineBasicBlock *TBB = 0, *FBB = 0;
+ SmallVector<MachineOperand, 4> Cond;
+ return !tii_->AnalyzeBranch(*MBB, TBB, FBB, Cond) && !TBB && !FBB &&
+ MBB->isSuccessor(SuccMBB);
+}
+
+/// removeRange - Wrapper for LiveInterval::removeRange. This removes a range
+/// from a physical register live interval as well as from the live intervals
+/// of its sub-registers.
+static void removeRange(LiveInterval &li, unsigned Start, unsigned End,
+ LiveIntervals *li_, const TargetRegisterInfo *tri_) {
+ li.removeRange(Start, End, true);
+ if (TargetRegisterInfo::isPhysicalRegister(li.reg)) {
+ for (const unsigned* SR = tri_->getSubRegisters(li.reg); *SR; ++SR) {
+ if (!li_->hasInterval(*SR))
+ continue;
+ LiveInterval &sli = li_->getInterval(*SR);
+ unsigned RemoveEnd = Start;
+ while (RemoveEnd != End) {
+ LiveInterval::iterator LR = sli.FindLiveRangeContaining(Start);
+ if (LR == sli.end())
+ break;
+ RemoveEnd = (LR->end < End) ? LR->end : End;
+ sli.removeRange(Start, RemoveEnd, true);
+ Start = RemoveEnd;
+ }
+ }
+ }
+}
+
+/// TrimLiveIntervalToLastUse - If there is a last use in the same basic block
+/// as the copy instruction, trim the live interval to the last use and return
+/// true.
+bool
+SimpleRegisterCoalescing::TrimLiveIntervalToLastUse(unsigned CopyIdx,
+ MachineBasicBlock *CopyMBB,
+ LiveInterval &li,
+ const LiveRange *LR) {
+ unsigned MBBStart = li_->getMBBStartIdx(CopyMBB);
+ unsigned LastUseIdx;
+ MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
+ LastUseIdx);
+ if (LastUse) {
+ MachineInstr *LastUseMI = LastUse->getParent();
+ if (!isSameOrFallThroughBB(LastUseMI->getParent(), CopyMBB, tii_)) {
+ // r1024 = op
+ // ...
+ // BB1:
+ // = r1024
+ //
+ // BB2:
+ // r1025<dead> = r1024<kill>
+ if (MBBStart < LR->end)
+ removeRange(li, MBBStart, LR->end, li_, tri_);
+ return true;
+ }
+
+ // There are uses before the copy, just shorten the live range to the end
+ // of last use.
+ LastUse->setIsKill();
+ removeRange(li, li_->getDefIndex(LastUseIdx), LR->end, li_, tri_);
+ li.addKill(LR->valno, LastUseIdx+1, false);
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (tii_->isMoveInstr(*LastUseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
+ DstReg == li.reg) {
+ // Last use is itself an identity code.
+ int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
+ LastUseMI->getOperand(DeadIdx).setIsDead();
+ }
+ return true;
+ }
+
+ // Is it livein?
+ if (LR->start <= MBBStart && LR->end > MBBStart) {
+ if (LR->start == 0) {
+ assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
+ // Live-in to the function but dead. Remove it from entry live-in set.
+ mf_->begin()->removeLiveIn(li.reg);
+ }
+ // FIXME: Shorten intervals in BBs that reaches this BB.
+ }
+
+ return false;
+}
+
+/// ReMaterializeTrivialDef - If the source of a copy is defined by a trivial
+/// computation, replace the copy by rematerialize the definition.
+bool SimpleRegisterCoalescing::ReMaterializeTrivialDef(LiveInterval &SrcInt,
+ unsigned DstReg,
+ MachineInstr *CopyMI) {
+ unsigned CopyIdx = li_->getUseIndex(li_->getInstructionIndex(CopyMI));
+ LiveInterval::iterator SrcLR = SrcInt.FindLiveRangeContaining(CopyIdx);
+ assert(SrcLR != SrcInt.end() && "Live range not found!");
+ VNInfo *ValNo = SrcLR->valno;
+ // If other defs can reach uses of this def, then it's not safe to perform
+ // the optimization. FIXME: Do isPHIDef and isDefAccurate both need to be
+ // tested?
+ if (ValNo->isPHIDef() || !ValNo->isDefAccurate() ||
+ ValNo->isUnused() || ValNo->hasPHIKill())
+ return false;
+ MachineInstr *DefMI = li_->getInstructionFromIndex(ValNo->def);
+ const TargetInstrDesc &TID = DefMI->getDesc();
+ if (!TID.isAsCheapAsAMove())
+ return false;
+ if (!DefMI->getDesc().isRematerializable() ||
+ !tii_->isTriviallyReMaterializable(DefMI))
+ return false;
+ bool SawStore = false;
+ if (!DefMI->isSafeToMove(tii_, SawStore))
+ return false;
+
+ unsigned DefIdx = li_->getDefIndex(CopyIdx);
+ const LiveRange *DLR= li_->getInterval(DstReg).getLiveRangeContaining(DefIdx);
+ DLR->valno->copy = NULL;
+ // Don't forget to update sub-register intervals.
+ if (TargetRegisterInfo::isPhysicalRegister(DstReg)) {
+ for (const unsigned* SR = tri_->getSubRegisters(DstReg); *SR; ++SR) {
+ if (!li_->hasInterval(*SR))
+ continue;
+ DLR = li_->getInterval(*SR).getLiveRangeContaining(DefIdx);
+ if (DLR && DLR->valno->copy == CopyMI)
+ DLR->valno->copy = NULL;
+ }
+ }
+
+ // If copy kills the source register, find the last use and propagate
+ // kill.
+ bool checkForDeadDef = false;
+ MachineBasicBlock *MBB = CopyMI->getParent();
+ if (CopyMI->killsRegister(SrcInt.reg))
+ if (!TrimLiveIntervalToLastUse(CopyIdx, MBB, SrcInt, SrcLR)) {
+ checkForDeadDef = true;
+ }
+
+ MachineBasicBlock::iterator MII = next(MachineBasicBlock::iterator(CopyMI));
+ tii_->reMaterialize(*MBB, MII, DstReg, DefMI);
+ MachineInstr *NewMI = prior(MII);
+
+ if (checkForDeadDef) {
+ // PR4090 fix: Trim interval failed because there was no use of the
+ // source interval in this MBB. If the def is in this MBB too then we
+ // should mark it dead:
+ if (DefMI->getParent() == MBB) {
+ DefMI->addRegisterDead(SrcInt.reg, tri_);
+ SrcLR->end = SrcLR->start + 1;
+ }
+ }
+
+ // CopyMI may have implicit operands, transfer them over to the newly
+ // rematerialized instruction. And update implicit def interval valnos.
+ for (unsigned i = CopyMI->getDesc().getNumOperands(),
+ e = CopyMI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = CopyMI->getOperand(i);
+ if (MO.isReg() && MO.isImplicit())
+ NewMI->addOperand(MO);
+ if (MO.isDef() && li_->hasInterval(MO.getReg())) {
+ unsigned Reg = MO.getReg();
+ DLR = li_->getInterval(Reg).getLiveRangeContaining(DefIdx);
+ if (DLR && DLR->valno->copy == CopyMI)
+ DLR->valno->copy = NULL;
+ }
+ }
+
+ li_->ReplaceMachineInstrInMaps(CopyMI, NewMI);
+ CopyMI->eraseFromParent();
+ ReMatCopies.insert(CopyMI);
+ ReMatDefs.insert(DefMI);
+ ++NumReMats;
+ return true;
+}
+
/// isBackEdgeCopy - Returns true if CopyMI is a back edge copy.
///
bool SimpleRegisterCoalescing::isBackEdgeCopy(MachineInstr *CopyMI,
LI.FindLiveRangeContaining(li_->getDefIndex(DefIdx));
if (DstLR == LI.end())
return false;
- unsigned KillIdx = li_->getInstructionIndex(&MBB->back()) + InstrSlots::NUM;
- if (DstLR->valno->kills.size() == 1 &&
- DstLR->valno->kills[0] == KillIdx && DstLR->valno->hasPHIKill)
+ if (DstLR->valno->kills.size() == 1 && DstLR->valno->kills[0].isPHIKill)
return true;
return false;
}
unsigned UseDstReg = DstReg;
if (OldSubIdx)
UseDstReg = tri_->getSubReg(DstReg, OldSubIdx);
+
+ unsigned CopySrcReg, CopyDstReg, CopySrcSubIdx, CopyDstSubIdx;
+ if (tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg,
+ CopySrcSubIdx, CopyDstSubIdx) &&
+ CopySrcReg != CopyDstReg &&
+ CopySrcReg == SrcReg && CopyDstReg != UseDstReg) {
+ // If the use is a copy and it won't be coalesced away, and its source
+ // is defined by a trivial computation, try to rematerialize it instead.
+ if (ReMaterializeTrivialDef(li_->getInterval(SrcReg), CopyDstReg,UseMI))
+ continue;
+ }
+
O.setReg(UseDstReg);
O.setSubReg(0);
- } else {
- // Sub-register indexes goes from small to large. e.g.
- // RAX: 0 -> AL, 1 -> AH, 2 -> AX, 3 -> EAX
- // EAX: 0 -> AL, 1 -> AH, 2 -> AX
- // So RAX's sub-register 2 is AX, RAX's sub-regsiter 3 is EAX, whose
- // sub-register 2 is also AX.
- if (SubIdx && OldSubIdx && SubIdx != OldSubIdx)
- assert(OldSubIdx < SubIdx && "Conflicting sub-register index!");
- else if (SubIdx)
- O.setSubReg(SubIdx);
- // Remove would-be duplicated kill marker.
- if (O.isKill() && UseMI->killsRegister(DstReg))
- O.setIsKill(false);
- O.setReg(DstReg);
+ continue;
+ }
+
+ // Sub-register indexes goes from small to large. e.g.
+ // RAX: 1 -> AL, 2 -> AX, 3 -> EAX
+ // EAX: 1 -> AL, 2 -> AX
+ // So RAX's sub-register 2 is AX, RAX's sub-regsiter 3 is EAX, whose
+ // sub-register 2 is also AX.
+ if (SubIdx && OldSubIdx && SubIdx != OldSubIdx)
+ assert(OldSubIdx < SubIdx && "Conflicting sub-register index!");
+ else if (SubIdx)
+ O.setSubReg(SubIdx);
+ // Remove would-be duplicated kill marker.
+ if (O.isKill() && UseMI->killsRegister(DstReg))
+ O.setIsKill(false);
+ O.setReg(DstReg);
+
+ // After updating the operand, check if the machine instruction has
+ // become a copy. If so, update its val# information.
+ if (JoinedCopies.count(UseMI))
+ continue;
+
+ const TargetInstrDesc &TID = UseMI->getDesc();
+ unsigned CopySrcReg, CopyDstReg, CopySrcSubIdx, CopyDstSubIdx;
+ if (TID.getNumDefs() == 1 && TID.getNumOperands() > 2 &&
+ tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg,
+ CopySrcSubIdx, CopyDstSubIdx) &&
+ CopySrcReg != CopyDstReg &&
+ (TargetRegisterInfo::isVirtualRegister(CopyDstReg) ||
+ allocatableRegs_[CopyDstReg])) {
+ LiveInterval &LI = li_->getInterval(CopyDstReg);
+ unsigned DefIdx = li_->getDefIndex(li_->getInstructionIndex(UseMI));
+ if (const LiveRange *DLR = LI.getLiveRangeContaining(DefIdx)) {
+ if (DLR->valno->def == DefIdx)
+ DLR->valno->copy = UseMI;
+ }
}
}
}
MachineOperand &UseMO = UI.getOperand();
if (UseMO.isKill()) {
MachineInstr *UseMI = UseMO.getParent();
- unsigned SReg, DReg;
- if (!tii_->isMoveInstr(*UseMI, SReg, DReg))
- continue;
unsigned UseIdx = li_->getUseIndex(li_->getInstructionIndex(UseMI));
- if (JoinedCopies.count(UseMI))
- continue;
const LiveRange *UI = LI.getLiveRangeContaining(UseIdx);
- if (!LI.isKill(UI->valno, UseIdx+1))
+ if (!UI || !LI.isKill(UI->valno, UseIdx+1))
UseMO.setIsKill(false);
}
}
}
-/// removeRange - Wrapper for LiveInterval::removeRange. This removes a range
-/// from a physical register live interval as well as from the live intervals
-/// of its sub-registers.
-static void removeRange(LiveInterval &li, unsigned Start, unsigned End,
- LiveIntervals *li_, const TargetRegisterInfo *tri_) {
- li.removeRange(Start, End, true);
- if (TargetRegisterInfo::isPhysicalRegister(li.reg)) {
- for (const unsigned* SR = tri_->getSubRegisters(li.reg); *SR; ++SR) {
- if (!li_->hasInterval(*SR))
- continue;
- LiveInterval &sli = li_->getInterval(*SR);
- unsigned RemoveEnd = Start;
- while (RemoveEnd != End) {
- LiveInterval::iterator LR = sli.FindLiveRangeContaining(Start);
- if (LR == sli.end())
- break;
- RemoveEnd = (LR->end < End) ? LR->end : End;
- sli.removeRange(Start, RemoveEnd, true);
- Start = RemoveEnd;
- }
- }
- }
-}
-
/// removeIntervalIfEmpty - Check if the live interval of a physical register
/// is empty, if so remove it and also remove the empty intervals of its
/// sub-registers. Return true if live interval is removed.
return false;
}
+/// RemoveDeadDef - If a def of a live interval is now determined dead, remove
+/// the val# it defines. If the live interval becomes empty, remove it as well.
+bool SimpleRegisterCoalescing::RemoveDeadDef(LiveInterval &li,
+ MachineInstr *DefMI) {
+ unsigned DefIdx = li_->getDefIndex(li_->getInstructionIndex(DefMI));
+ LiveInterval::iterator MLR = li.FindLiveRangeContaining(DefIdx);
+ if (DefIdx != MLR->valno->def)
+ return false;
+ li.removeValNo(MLR->valno);
+ return removeIntervalIfEmpty(li, li_, tri_);
+}
+
/// PropagateDeadness - Propagate the dead marker to the instruction which
/// defines the val#.
static void PropagateDeadness(LiveInterval &li, MachineInstr *CopyMI,
// first instruction index starts at > 0 value.
assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
// Live-in to the function but dead. Remove it from entry live-in set.
- mf_->begin()->removeLiveIn(li.reg);
+ if (mf_->begin()->isLiveIn(li.reg))
+ mf_->begin()->removeLiveIn(li.reg);
const LiveRange *LR = li.getLiveRangeContaining(CopyIdx);
removeRange(li, LR->start, LR->end, li_, tri_);
return removeIntervalIfEmpty(li, li_, tri_);
// More uses past this copy? Nothing to do.
return false;
- unsigned LastUseIdx;
- MachineOperand *LastUse = lastRegisterUse(LR->start, CopyIdx-1, li.reg,
- LastUseIdx);
- if (LastUse) {
- // There are uses before the copy, just shorten the live range to the end
- // of last use.
- LastUse->setIsKill();
- MachineInstr *LastUseMI = LastUse->getParent();
- removeRange(li, li_->getDefIndex(LastUseIdx), LR->end, li_, tri_);
- unsigned SrcReg, DstReg;
- if (tii_->isMoveInstr(*LastUseMI, SrcReg, DstReg) &&
- DstReg == li.reg) {
- // Last use is itself an identity code.
- int DeadIdx = LastUseMI->findRegisterDefOperandIdx(li.reg, false, tri_);
- LastUseMI->getOperand(DeadIdx).setIsDead();
- }
+ // If there is a last use in the same bb, we can't remove the live range.
+ // Shorten the live interval and return.
+ MachineBasicBlock *CopyMBB = CopyMI->getParent();
+ if (TrimLiveIntervalToLastUse(CopyIdx, CopyMBB, li, LR))
return false;
- }
- // Is it livein?
- MachineBasicBlock *CopyMBB = CopyMI->getParent();
- unsigned MBBStart = li_->getMBBStartIdx(CopyMBB);
- if (LR->start <= MBBStart && LR->end > MBBStart) {
- if (LR->start == 0) {
- assert(TargetRegisterInfo::isPhysicalRegister(li.reg));
- // Live-in to the function but dead. Remove it from entry live-in set.
- mf_->begin()->removeLiveIn(li.reg);
+ MachineBasicBlock *StartMBB = li_->getMBBFromIndex(RemoveStart);
+ if (!isSameOrFallThroughBB(StartMBB, CopyMBB, tii_))
+ // If the live range starts in another mbb and the copy mbb is not a fall
+ // through mbb, then we can only cut the range from the beginning of the
+ // copy mbb.
+ RemoveStart = li_->getMBBStartIdx(CopyMBB) + 1;
+
+ if (LR->valno->def == RemoveStart) {
+ // If the def MI defines the val# and this copy is the only kill of the
+ // val#, then propagate the dead marker.
+ if (li.isOnlyLROfValNo(LR)) {
+ PropagateDeadness(li, CopyMI, RemoveStart, li_, tri_);
+ ++numDeadValNo;
}
- // FIXME: Shorten intervals in BBs that reaches this BB.
+ if (li.isKill(LR->valno, RemoveEnd))
+ li.removeKill(LR->valno, RemoveEnd);
}
- if (LR->valno->def == RemoveStart)
- // If the def MI defines the val#, propagate the dead marker.
- PropagateDeadness(li, CopyMI, RemoveStart, li_, tri_);
-
- removeRange(li, RemoveStart, LR->end, li_, tri_);
+ removeRange(li, RemoveStart, RemoveEnd, li_, tri_);
return removeIntervalIfEmpty(li, li_, tri_);
}
LiveInterval::iterator LR = li.FindLiveRangeContaining(CopyIdx);
if (LR == li.end())
return false;
- if (LR->valno->hasPHIKill)
+ if (LR->valno->hasPHIKill())
return false;
if (LR->valno->def != CopyIdx)
return false;
if (ULR == li.end() || ULR->valno != LR->valno)
continue;
// If the use is not a use, then it's not safe to coalesce the move.
- unsigned SrcReg, DstReg;
- if (!tii_->isMoveInstr(*UseMI, SrcReg, DstReg)) {
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (!tii_->isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)) {
if (UseMI->getOpcode() == TargetInstrInfo::INSERT_SUBREG &&
UseMI->getOperand(1).getReg() == li.reg)
continue;
}
-/// RemoveCopiesFromValNo - The specified value# is defined by an implicit
-/// def and it is being removed. Turn all copies from this value# into
-/// identity copies so they will be removed.
-void SimpleRegisterCoalescing::RemoveCopiesFromValNo(LiveInterval &li,
- VNInfo *VNI) {
- MachineInstr *ImpDef = NULL;
+/// TurnCopiesFromValNoToImpDefs - The specified value# is defined by an
+/// implicit_def and it is being removed. Turn all copies from this value#
+/// into implicit_defs.
+void SimpleRegisterCoalescing::TurnCopiesFromValNoToImpDefs(LiveInterval &li,
+ VNInfo *VNI) {
+ SmallVector<MachineInstr*, 4> ImpDefs;
MachineOperand *LastUse = NULL;
unsigned LastUseIdx = li_->getUseIndex(VNI->def);
for (MachineRegisterInfo::reg_iterator RI = mri_->reg_begin(li.reg),
MachineInstr *MI = &*RI;
++RI;
if (MO->isDef()) {
- if (MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF) {
- assert(!ImpDef && "Multiple implicit_def defining same register?");
- ImpDef = MI;
- }
+ if (MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF)
+ ImpDefs.push_back(MI);
continue;
}
if (JoinedCopies.count(MI))
if (ULR == li.end() || ULR->valno != VNI)
continue;
// If the use is a copy, turn it into an identity copy.
- unsigned SrcReg, DstReg;
- if (tii_->isMoveInstr(*MI, SrcReg, DstReg) && SrcReg == li.reg) {
- // Each use MI may have multiple uses of this register. Change them all.
- for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
- MachineOperand &MO = MI->getOperand(i);
- if (MO.isReg() && MO.getReg() == li.reg)
- MO.setReg(DstReg);
- }
- JoinedCopies.insert(MI);
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
+ SrcReg == li.reg) {
+ // Change it to an implicit_def.
+ MI->setDesc(tii_->get(TargetInstrInfo::IMPLICIT_DEF));
+ for (int i = MI->getNumOperands() - 1, e = 0; i > e; --i)
+ MI->RemoveOperand(i);
+ // It's no longer a copy, update the valno it defines.
+ unsigned DefIdx = li_->getDefIndex(UseIdx);
+ LiveInterval &DstInt = li_->getInterval(DstReg);
+ LiveInterval::iterator DLR = DstInt.FindLiveRangeContaining(DefIdx);
+ assert(DLR != DstInt.end() && "Live range not found!");
+ assert(DLR->valno->copy == MI);
+ DLR->valno->copy = NULL;
+ ReMatCopies.insert(MI);
} else if (UseIdx > LastUseIdx) {
LastUseIdx = UseIdx;
LastUse = MO;
}
}
- if (LastUse)
+ if (LastUse) {
LastUse->setIsKill();
- else {
- // Remove dead implicit_def.
- li_->RemoveMachineInstrFromMaps(ImpDef);
- ImpDef->eraseFromParent();
+ li.addKill(VNI, LastUseIdx+1, false);
+ } else {
+ // Remove dead implicit_def's.
+ while (!ImpDefs.empty()) {
+ MachineInstr *ImpDef = ImpDefs.back();
+ ImpDefs.pop_back();
+ li_->RemoveMachineInstrFromMaps(ImpDef);
+ ImpDef->eraseFromParent();
+ }
}
}
-static unsigned getMatchingSuperReg(unsigned Reg, unsigned SubIdx,
- const TargetRegisterClass *RC,
- const TargetRegisterInfo* TRI) {
- for (const unsigned *SRs = TRI->getSuperRegisters(Reg);
- unsigned SR = *SRs; ++SRs)
- if (Reg == TRI->getSubReg(SR, SubIdx) && RC->contains(SR))
- return SR;
- return 0;
+/// isWinToJoinVRWithSrcPhysReg - Return true if it's worth while to join a
+/// a virtual destination register with physical source register.
+bool
+SimpleRegisterCoalescing::isWinToJoinVRWithSrcPhysReg(MachineInstr *CopyMI,
+ MachineBasicBlock *CopyMBB,
+ LiveInterval &DstInt,
+ LiveInterval &SrcInt) {
+ // If the virtual register live interval is long but it has low use desity,
+ // do not join them, instead mark the physical register as its allocation
+ // preference.
+ const TargetRegisterClass *RC = mri_->getRegClass(DstInt.reg);
+ unsigned Threshold = allocatableRCRegs_[RC].count() * 2;
+ unsigned Length = li_->getApproximateInstructionCount(DstInt);
+ if (Length > Threshold &&
+ (((float)std::distance(mri_->use_begin(DstInt.reg),
+ mri_->use_end()) / Length) < (1.0 / Threshold)))
+ return false;
+
+ // If the virtual register live interval extends into a loop, turn down
+ // aggressiveness.
+ unsigned CopyIdx = li_->getDefIndex(li_->getInstructionIndex(CopyMI));
+ const MachineLoop *L = loopInfo->getLoopFor(CopyMBB);
+ if (!L) {
+ // Let's see if the virtual register live interval extends into the loop.
+ LiveInterval::iterator DLR = DstInt.FindLiveRangeContaining(CopyIdx);
+ assert(DLR != DstInt.end() && "Live range not found!");
+ DLR = DstInt.FindLiveRangeContaining(DLR->end+1);
+ if (DLR != DstInt.end()) {
+ CopyMBB = li_->getMBBFromIndex(DLR->start);
+ L = loopInfo->getLoopFor(CopyMBB);
+ }
+ }
+
+ if (!L || Length <= Threshold)
+ return true;
+
+ unsigned UseIdx = li_->getUseIndex(CopyIdx);
+ LiveInterval::iterator SLR = SrcInt.FindLiveRangeContaining(UseIdx);
+ MachineBasicBlock *SMBB = li_->getMBBFromIndex(SLR->start);
+ if (loopInfo->getLoopFor(SMBB) != L) {
+ if (!loopInfo->isLoopHeader(CopyMBB))
+ return false;
+ // If vr's live interval extends pass the loop header, do not join.
+ for (MachineBasicBlock::succ_iterator SI = CopyMBB->succ_begin(),
+ SE = CopyMBB->succ_end(); SI != SE; ++SI) {
+ MachineBasicBlock *SuccMBB = *SI;
+ if (SuccMBB == CopyMBB)
+ continue;
+ if (DstInt.overlaps(li_->getMBBStartIdx(SuccMBB),
+ li_->getMBBEndIdx(SuccMBB)+1))
+ return false;
+ }
+ }
+ return true;
+}
+
+/// isWinToJoinVRWithDstPhysReg - Return true if it's worth while to join a
+/// copy from a virtual source register to a physical destination register.
+bool
+SimpleRegisterCoalescing::isWinToJoinVRWithDstPhysReg(MachineInstr *CopyMI,
+ MachineBasicBlock *CopyMBB,
+ LiveInterval &DstInt,
+ LiveInterval &SrcInt) {
+ // If the virtual register live interval is long but it has low use desity,
+ // do not join them, instead mark the physical register as its allocation
+ // preference.
+ const TargetRegisterClass *RC = mri_->getRegClass(SrcInt.reg);
+ unsigned Threshold = allocatableRCRegs_[RC].count() * 2;
+ unsigned Length = li_->getApproximateInstructionCount(SrcInt);
+ if (Length > Threshold &&
+ (((float)std::distance(mri_->use_begin(SrcInt.reg),
+ mri_->use_end()) / Length) < (1.0 / Threshold)))
+ return false;
+
+ if (SrcInt.empty())
+ // Must be implicit_def.
+ return false;
+
+ // If the virtual register live interval is defined or cross a loop, turn
+ // down aggressiveness.
+ unsigned CopyIdx = li_->getDefIndex(li_->getInstructionIndex(CopyMI));
+ unsigned UseIdx = li_->getUseIndex(CopyIdx);
+ LiveInterval::iterator SLR = SrcInt.FindLiveRangeContaining(UseIdx);
+ assert(SLR != SrcInt.end() && "Live range not found!");
+ SLR = SrcInt.FindLiveRangeContaining(SLR->start-1);
+ if (SLR == SrcInt.end())
+ return true;
+ MachineBasicBlock *SMBB = li_->getMBBFromIndex(SLR->start);
+ const MachineLoop *L = loopInfo->getLoopFor(SMBB);
+
+ if (!L || Length <= Threshold)
+ return true;
+
+ if (loopInfo->getLoopFor(CopyMBB) != L) {
+ if (SMBB != L->getLoopLatch())
+ return false;
+ // If vr's live interval is extended from before the loop latch, do not
+ // join.
+ for (MachineBasicBlock::pred_iterator PI = SMBB->pred_begin(),
+ PE = SMBB->pred_end(); PI != PE; ++PI) {
+ MachineBasicBlock *PredMBB = *PI;
+ if (PredMBB == SMBB)
+ continue;
+ if (SrcInt.overlaps(li_->getMBBStartIdx(PredMBB),
+ li_->getMBBEndIdx(PredMBB)+1))
+ return false;
+ }
+ }
+ return true;
+}
+
+/// isWinToJoinCrossClass - Return true if it's profitable to coalesce
+/// two virtual registers from different register classes.
+bool
+SimpleRegisterCoalescing::isWinToJoinCrossClass(unsigned LargeReg,
+ unsigned SmallReg,
+ unsigned Threshold) {
+ // Then make sure the intervals are *short*.
+ LiveInterval &LargeInt = li_->getInterval(LargeReg);
+ LiveInterval &SmallInt = li_->getInterval(SmallReg);
+ unsigned LargeSize = li_->getApproximateInstructionCount(LargeInt);
+ unsigned SmallSize = li_->getApproximateInstructionCount(SmallInt);
+ if (SmallSize > Threshold || LargeSize > Threshold)
+ if ((float)std::distance(mri_->use_begin(SmallReg),
+ mri_->use_end()) / SmallSize <
+ (float)std::distance(mri_->use_begin(LargeReg),
+ mri_->use_end()) / LargeSize)
+ return false;
+ return true;
+}
+
+/// HasIncompatibleSubRegDefUse - If we are trying to coalesce a virtual
+/// register with a physical register, check if any of the virtual register
+/// operand is a sub-register use or def. If so, make sure it won't result
+/// in an illegal extract_subreg or insert_subreg instruction. e.g.
+/// vr1024 = extract_subreg vr1025, 1
+/// ...
+/// vr1024 = mov8rr AH
+/// If vr1024 is coalesced with AH, the extract_subreg is now illegal since
+/// AH does not have a super-reg whose sub-register 1 is AH.
+bool
+SimpleRegisterCoalescing::HasIncompatibleSubRegDefUse(MachineInstr *CopyMI,
+ unsigned VirtReg,
+ unsigned PhysReg) {
+ for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(VirtReg),
+ E = mri_->reg_end(); I != E; ++I) {
+ MachineOperand &O = I.getOperand();
+ MachineInstr *MI = &*I;
+ if (MI == CopyMI || JoinedCopies.count(MI))
+ continue;
+ unsigned SubIdx = O.getSubReg();
+ if (SubIdx && !tri_->getSubReg(PhysReg, SubIdx))
+ return true;
+ if (MI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG) {
+ SubIdx = MI->getOperand(2).getImm();
+ if (O.isUse() && !tri_->getSubReg(PhysReg, SubIdx))
+ return true;
+ if (O.isDef()) {
+ unsigned SrcReg = MI->getOperand(1).getReg();
+ const TargetRegisterClass *RC =
+ TargetRegisterInfo::isPhysicalRegister(SrcReg)
+ ? tri_->getPhysicalRegisterRegClass(SrcReg)
+ : mri_->getRegClass(SrcReg);
+ if (!tri_->getMatchingSuperReg(PhysReg, SubIdx, RC))
+ return true;
+ }
+ }
+ if (MI->getOpcode() == TargetInstrInfo::INSERT_SUBREG ||
+ MI->getOpcode() == TargetInstrInfo::SUBREG_TO_REG) {
+ SubIdx = MI->getOperand(3).getImm();
+ if (VirtReg == MI->getOperand(0).getReg()) {
+ if (!tri_->getSubReg(PhysReg, SubIdx))
+ return true;
+ } else {
+ unsigned DstReg = MI->getOperand(0).getReg();
+ const TargetRegisterClass *RC =
+ TargetRegisterInfo::isPhysicalRegister(DstReg)
+ ? tri_->getPhysicalRegisterRegClass(DstReg)
+ : mri_->getRegClass(DstReg);
+ if (!tri_->getMatchingSuperReg(PhysReg, SubIdx, RC))
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+
+/// CanJoinExtractSubRegToPhysReg - Return true if it's possible to coalesce
+/// an extract_subreg where dst is a physical register, e.g.
+/// cl = EXTRACT_SUBREG reg1024, 1
+bool
+SimpleRegisterCoalescing::CanJoinExtractSubRegToPhysReg(unsigned DstReg,
+ unsigned SrcReg, unsigned SubIdx,
+ unsigned &RealDstReg) {
+ const TargetRegisterClass *RC = mri_->getRegClass(SrcReg);
+ RealDstReg = tri_->getMatchingSuperReg(DstReg, SubIdx, RC);
+ assert(RealDstReg && "Invalid extract_subreg instruction!");
+
+ // For this type of EXTRACT_SUBREG, conservatively
+ // check if the live interval of the source register interfere with the
+ // actual super physical register we are trying to coalesce with.
+ LiveInterval &RHS = li_->getInterval(SrcReg);
+ if (li_->hasInterval(RealDstReg) &&
+ RHS.overlaps(li_->getInterval(RealDstReg))) {
+ DOUT << "Interfere with register ";
+ DEBUG(li_->getInterval(RealDstReg).print(DOUT, tri_));
+ return false; // Not coalescable
+ }
+ for (const unsigned* SR = tri_->getSubRegisters(RealDstReg); *SR; ++SR)
+ if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) {
+ DOUT << "Interfere with sub-register ";
+ DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ return false; // Not coalescable
+ }
+ return true;
+}
+
+/// CanJoinInsertSubRegToPhysReg - Return true if it's possible to coalesce
+/// an insert_subreg where src is a physical register, e.g.
+/// reg1024 = INSERT_SUBREG reg1024, c1, 0
+bool
+SimpleRegisterCoalescing::CanJoinInsertSubRegToPhysReg(unsigned DstReg,
+ unsigned SrcReg, unsigned SubIdx,
+ unsigned &RealSrcReg) {
+ const TargetRegisterClass *RC = mri_->getRegClass(DstReg);
+ RealSrcReg = tri_->getMatchingSuperReg(SrcReg, SubIdx, RC);
+ assert(RealSrcReg && "Invalid extract_subreg instruction!");
+
+ LiveInterval &RHS = li_->getInterval(DstReg);
+ if (li_->hasInterval(RealSrcReg) &&
+ RHS.overlaps(li_->getInterval(RealSrcReg))) {
+ DOUT << "Interfere with register ";
+ DEBUG(li_->getInterval(RealSrcReg).print(DOUT, tri_));
+ return false; // Not coalescable
+ }
+ for (const unsigned* SR = tri_->getSubRegisters(RealSrcReg); *SR; ++SR)
+ if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) {
+ DOUT << "Interfere with sub-register ";
+ DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ return false; // Not coalescable
+ }
+ return true;
+}
+
+/// getRegAllocPreference - Return register allocation preference register.
+///
+static unsigned getRegAllocPreference(unsigned Reg, MachineFunction &MF,
+ MachineRegisterInfo *MRI,
+ const TargetRegisterInfo *TRI) {
+ if (TargetRegisterInfo::isPhysicalRegister(Reg))
+ return 0;
+ std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
+ return TRI->ResolveRegAllocHint(Hint.first, Hint.second, MF);
}
/// JoinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
MachineInstr *CopyMI = TheCopy.MI;
Again = false;
- if (JoinedCopies.count(CopyMI))
+ if (JoinedCopies.count(CopyMI) || ReMatCopies.count(CopyMI))
return false; // Already done.
DOUT << li_->getInstructionIndex(CopyMI) << '\t' << *CopyMI;
- unsigned SrcReg;
- unsigned DstReg;
+ unsigned SrcReg, DstReg, SrcSubIdx = 0, DstSubIdx = 0;
bool isExtSubReg = CopyMI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG;
bool isInsSubReg = CopyMI->getOpcode() == TargetInstrInfo::INSERT_SUBREG;
+ bool isSubRegToReg = CopyMI->getOpcode() == TargetInstrInfo::SUBREG_TO_REG;
unsigned SubIdx = 0;
if (isExtSubReg) {
- DstReg = CopyMI->getOperand(0).getReg();
- SrcReg = CopyMI->getOperand(1).getReg();
- } else if (isInsSubReg) {
+ DstReg = CopyMI->getOperand(0).getReg();
+ DstSubIdx = CopyMI->getOperand(0).getSubReg();
+ SrcReg = CopyMI->getOperand(1).getReg();
+ SrcSubIdx = CopyMI->getOperand(2).getImm();
+ } else if (isInsSubReg || isSubRegToReg) {
if (CopyMI->getOperand(2).getSubReg()) {
DOUT << "\tSource of insert_subreg is already coalesced "
<< "to another register.\n";
return false; // Not coalescable.
}
- DstReg = CopyMI->getOperand(0).getReg();
- SrcReg = CopyMI->getOperand(2).getReg();
- } else if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg)) {
+ DstReg = CopyMI->getOperand(0).getReg();
+ DstSubIdx = CopyMI->getOperand(3).getImm();
+ SrcReg = CopyMI->getOperand(2).getReg();
+ } else if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)){
assert(0 && "Unrecognized copy instruction!");
return false;
}
return false; // Not coalescable.
}
+ // Check that a physical source register is compatible with dst regclass
+ if (SrcIsPhys) {
+ unsigned SrcSubReg = SrcSubIdx ?
+ tri_->getSubReg(SrcReg, SrcSubIdx) : SrcReg;
+ const TargetRegisterClass *DstRC = mri_->getRegClass(DstReg);
+ const TargetRegisterClass *DstSubRC = DstRC;
+ if (DstSubIdx)
+ DstSubRC = DstRC->getSubRegisterRegClass(DstSubIdx);
+ assert(DstSubRC && "Illegal subregister index");
+ if (!DstSubRC->contains(SrcSubReg)) {
+ DOUT << "\tIncompatible destination regclass: "
+ << tri_->getName(SrcSubReg) << " not in " << DstSubRC->getName()
+ << ".\n";
+ return false; // Not coalescable.
+ }
+ }
+
+ // Check that a physical dst register is compatible with source regclass
+ if (DstIsPhys) {
+ unsigned DstSubReg = DstSubIdx ?
+ tri_->getSubReg(DstReg, DstSubIdx) : DstReg;
+ const TargetRegisterClass *SrcRC = mri_->getRegClass(SrcReg);
+ const TargetRegisterClass *SrcSubRC = SrcRC;
+ if (SrcSubIdx)
+ SrcSubRC = SrcRC->getSubRegisterRegClass(SrcSubIdx);
+ assert(SrcSubRC && "Illegal subregister index");
+ if (!SrcSubRC->contains(DstReg)) {
+ DOUT << "\tIncompatible source regclass: "
+ << tri_->getName(DstSubReg) << " not in " << SrcSubRC->getName()
+ << ".\n";
+ return false; // Not coalescable.
+ }
+ }
+
+ // Should be non-null only when coalescing to a sub-register class.
+ bool CrossRC = false;
+ const TargetRegisterClass *NewRC = NULL;
+ MachineBasicBlock *CopyMBB = CopyMI->getParent();
unsigned RealDstReg = 0;
unsigned RealSrcReg = 0;
- if (isExtSubReg || isInsSubReg) {
+ if (isExtSubReg || isInsSubReg || isSubRegToReg) {
SubIdx = CopyMI->getOperand(isExtSubReg ? 2 : 3).getImm();
if (SrcIsPhys && isExtSubReg) {
// r1024 = EXTRACT_SUBREG EAX, 0 then r1024 is really going to be
} else
SrcReg = tri_->getSubReg(SrcReg, SubIdx);
SubIdx = 0;
- } else if (DstIsPhys && isInsSubReg) {
+ } else if (DstIsPhys && (isInsSubReg || isSubRegToReg)) {
// EAX = INSERT_SUBREG EAX, r1024, 0
unsigned SrcSubIdx = CopyMI->getOperand(2).getSubReg();
if (SrcSubIdx) {
} else
DstReg = tri_->getSubReg(DstReg, SubIdx);
SubIdx = 0;
- } else if ((DstIsPhys && isExtSubReg) || (SrcIsPhys && isInsSubReg)) {
- // If this is a extract_subreg where dst is a physical register, e.g.
- // cl = EXTRACT_SUBREG reg1024, 1
- // then create and update the actual physical register allocated to RHS.
- // Ditto for
- // reg1024 = INSERT_SUBREG r1024, cl, 1
- if (CopyMI->getOperand(1).getSubReg()) {
- DOUT << "\tSrc of extract_ / insert_subreg already coalesced with reg"
+ } else if ((DstIsPhys && isExtSubReg) ||
+ (SrcIsPhys && (isInsSubReg || isSubRegToReg))) {
+ if (!isSubRegToReg && CopyMI->getOperand(1).getSubReg()) {
+ DOUT << "\tSrc of extract_subreg already coalesced with reg"
<< " of a super-class.\n";
return false; // Not coalescable.
}
- const TargetRegisterClass *RC =
- mri_->getRegClass(isExtSubReg ? SrcReg : DstReg);
+
if (isExtSubReg) {
- RealDstReg = getMatchingSuperReg(DstReg, SubIdx, RC, tri_);
- assert(RealDstReg && "Invalid extra_subreg instruction!");
+ if (!CanJoinExtractSubRegToPhysReg(DstReg, SrcReg, SubIdx, RealDstReg))
+ return false; // Not coalescable
} else {
- RealSrcReg = getMatchingSuperReg(SrcReg, SubIdx, RC, tri_);
- assert(RealSrcReg && "Invalid extra_subreg instruction!");
- }
-
- // For this type of EXTRACT_SUBREG, conservatively
- // check if the live interval of the source register interfere with the
- // actual super physical register we are trying to coalesce with.
- unsigned PhysReg = isExtSubReg ? RealDstReg : RealSrcReg;
- LiveInterval &RHS = li_->getInterval(isExtSubReg ? SrcReg : DstReg);
- if (li_->hasInterval(PhysReg) &&
- RHS.overlaps(li_->getInterval(PhysReg))) {
- DOUT << "Interfere with register ";
- DEBUG(li_->getInterval(PhysReg).print(DOUT, tri_));
- return false; // Not coalescable
- }
- for (const unsigned* SR = tri_->getSubRegisters(PhysReg); *SR; ++SR)
- if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) {
- DOUT << "Interfere with sub-register ";
- DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ if (!CanJoinInsertSubRegToPhysReg(DstReg, SrcReg, SubIdx, RealSrcReg))
return false; // Not coalescable
- }
+ }
SubIdx = 0;
} else {
unsigned OldSubIdx = isExtSubReg ? CopyMI->getOperand(0).getSubReg()
: CopyMI->getOperand(2).getSubReg();
if (OldSubIdx) {
- if (OldSubIdx == SubIdx)
+ if (OldSubIdx == SubIdx && !differingRegisterClasses(SrcReg, DstReg))
// r1024<2> = EXTRACT_SUBREG r1025, 2. Then r1024 has already been
// coalesced to a larger register so the subreg indices cancel out.
+ // Also check if the other larger register is of the same register
+ // class as the would be resulting register.
SubIdx = 0;
else {
DOUT << "\t Sub-register indices mismatch.\n";
if (SubIdx) {
unsigned LargeReg = isExtSubReg ? SrcReg : DstReg;
unsigned SmallReg = isExtSubReg ? DstReg : SrcReg;
- unsigned LargeRegSize =
- li_->getInterval(LargeReg).getSize() / InstrSlots::NUM;
- unsigned SmallRegSize =
- li_->getInterval(SmallReg).getSize() / InstrSlots::NUM;
- const TargetRegisterClass *RC = mri_->getRegClass(SmallReg);
- unsigned Threshold = allocatableRCRegs_[RC].count();
- // Be conservative. If both sides are virtual registers, do not coalesce
- // if this will cause a high use density interval to target a smaller
- // set of registers.
- if (SmallRegSize > Threshold || LargeRegSize > Threshold) {
- LiveVariables::VarInfo &svi = lv_->getVarInfo(LargeReg);
- LiveVariables::VarInfo &dvi = lv_->getVarInfo(SmallReg);
- if ((float)dvi.NumUses / SmallRegSize <
- (float)svi.NumUses / LargeRegSize) {
- Again = true; // May be possible to coalesce later.
- return false;
- }
+ unsigned Limit= allocatableRCRegs_[mri_->getRegClass(SmallReg)].count();
+ if (!isWinToJoinCrossClass(LargeReg, SmallReg, Limit)) {
+ Again = true; // May be possible to coalesce later.
+ return false;
}
}
}
} else if (differingRegisterClasses(SrcReg, DstReg)) {
- // FIXME: What if the resul of a EXTRACT_SUBREG is then coalesced
+ if (!CrossClassJoin)
+ return false;
+ CrossRC = true;
+
+ // FIXME: What if the result of a EXTRACT_SUBREG is then coalesced
// with another? If it's the resulting destination register, then
// the subidx must be propagated to uses (but only those defined
// by the EXTRACT_SUBREG). If it's being coalesced into another
// register, it should be safe because register is assumed to have
// the register class of the super-register.
- // If they are not of the same register class, we cannot join them.
- DOUT << "\tSrc/Dest are different register classes.\n";
- // Allow the coalescer to try again in case either side gets coalesced to
- // a physical register that's compatible with the other side. e.g.
- // r1024 = MOV32to32_ r1025
- // but later r1024 is assigned EAX then r1025 may be coalesced with EAX.
- Again = true; // May be possible to coalesce later.
- return false;
+ // Process moves where one of the registers have a sub-register index.
+ MachineOperand *DstMO = CopyMI->findRegisterDefOperand(DstReg);
+ MachineOperand *SrcMO = CopyMI->findRegisterUseOperand(SrcReg);
+ SubIdx = DstMO->getSubReg();
+ if (SubIdx) {
+ if (SrcMO->getSubReg())
+ // FIXME: can we handle this?
+ return false;
+ // This is not an insert_subreg but it looks like one.
+ // e.g. %reg1024:4 = MOV32rr %EAX
+ isInsSubReg = true;
+ if (SrcIsPhys) {
+ if (!CanJoinInsertSubRegToPhysReg(DstReg, SrcReg, SubIdx, RealSrcReg))
+ return false; // Not coalescable
+ SubIdx = 0;
+ }
+ } else {
+ SubIdx = SrcMO->getSubReg();
+ if (SubIdx) {
+ // This is not a extract_subreg but it looks like one.
+ // e.g. %cl = MOV16rr %reg1024:1
+ isExtSubReg = true;
+ if (DstIsPhys) {
+ if (!CanJoinExtractSubRegToPhysReg(DstReg, SrcReg, SubIdx,RealDstReg))
+ return false; // Not coalescable
+ SubIdx = 0;
+ }
+ }
+ }
+
+ const TargetRegisterClass *SrcRC= SrcIsPhys ? 0 : mri_->getRegClass(SrcReg);
+ const TargetRegisterClass *DstRC= DstIsPhys ? 0 : mri_->getRegClass(DstReg);
+ unsigned LargeReg = SrcReg;
+ unsigned SmallReg = DstReg;
+ unsigned Limit = 0;
+
+ // Now determine the register class of the joined register.
+ if (isExtSubReg) {
+ if (SubIdx && DstRC && DstRC->isASubClass()) {
+ // This is a move to a sub-register class. However, the source is a
+ // sub-register of a larger register class. We don't know what should
+ // the register class be. FIXME.
+ Again = true;
+ return false;
+ }
+ Limit = allocatableRCRegs_[DstRC].count();
+ } else if (!SrcIsPhys && !DstIsPhys) {
+ NewRC = getCommonSubClass(SrcRC, DstRC);
+ if (!NewRC) {
+ DOUT << "\tDisjoint regclasses: "
+ << SrcRC->getName() << ", "
+ << DstRC->getName() << ".\n";
+ return false; // Not coalescable.
+ }
+ if (DstRC->getSize() > SrcRC->getSize())
+ std::swap(LargeReg, SmallReg);
+ }
+
+ // If we are joining two virtual registers and the resulting register
+ // class is more restrictive (fewer register, smaller size). Check if it's
+ // worth doing the merge.
+ if (!SrcIsPhys && !DstIsPhys &&
+ (isExtSubReg || DstRC->isASubClass()) &&
+ !isWinToJoinCrossClass(LargeReg, SmallReg,
+ allocatableRCRegs_[NewRC].count())) {
+ DOUT << "\tSrc/Dest are different register classes.\n";
+ // Allow the coalescer to try again in case either side gets coalesced to
+ // a physical register that's compatible with the other side. e.g.
+ // r1024 = MOV32to32_ r1025
+ // But later r1024 is assigned EAX then r1025 may be coalesced with EAX.
+ Again = true; // May be possible to coalesce later.
+ return false;
+ }
}
+
+ // Will it create illegal extract_subreg / insert_subreg?
+ if (SrcIsPhys && HasIncompatibleSubRegDefUse(CopyMI, DstReg, SrcReg))
+ return false;
+ if (DstIsPhys && HasIncompatibleSubRegDefUse(CopyMI, SrcReg, DstReg))
+ return false;
LiveInterval &SrcInt = li_->getInterval(SrcReg);
LiveInterval &DstInt = li_->getInterval(DstReg);
DOUT << " and "; DstInt.print(DOUT, tri_);
DOUT << ": ";
+ // Save a copy of the virtual register live interval. We'll manually
+ // merge this into the "real" physical register live interval this is
+ // coalesced with.
+ LiveInterval *SavedLI = 0;
+ if (RealDstReg)
+ SavedLI = li_->dupInterval(&SrcInt);
+ else if (RealSrcReg)
+ SavedLI = li_->dupInterval(&DstInt);
+
// Check if it is necessary to propagate "isDead" property.
- if (!isExtSubReg && !isInsSubReg) {
+ if (!isExtSubReg && !isInsSubReg && !isSubRegToReg) {
MachineOperand *mopd = CopyMI->findRegisterDefOperand(DstReg, false);
bool isDead = mopd->isDead();
// these are not spillable! If the destination interval uses are far away,
// think twice about coalescing them!
if (!isDead && (SrcIsPhys || DstIsPhys)) {
- LiveInterval &JoinVInt = SrcIsPhys ? DstInt : SrcInt;
- unsigned JoinVReg = SrcIsPhys ? DstReg : SrcReg;
- unsigned JoinPReg = SrcIsPhys ? SrcReg : DstReg;
- const TargetRegisterClass *RC = mri_->getRegClass(JoinVReg);
- unsigned Threshold = allocatableRCRegs_[RC].count() * 2;
- if (TheCopy.isBackEdge)
- Threshold *= 2; // Favors back edge copies.
-
- // If the virtual register live interval is long but it has low use desity,
- // do not join them, instead mark the physical register as its allocation
- // preference.
- unsigned Length = JoinVInt.getSize() / InstrSlots::NUM;
- LiveVariables::VarInfo &vi = lv_->getVarInfo(JoinVReg);
- if (Length > Threshold &&
- (((float)vi.NumUses / Length) < (1.0 / Threshold))) {
- JoinVInt.preference = JoinPReg;
- ++numAborts;
- DOUT << "\tMay tie down a physical register, abort!\n";
- Again = true; // May be possible to coalesce later.
- return false;
+ // If the copy is in a loop, take care not to coalesce aggressively if the
+ // src is coming in from outside the loop (or the dst is out of the loop).
+ // If it's not in a loop, then determine whether to join them base purely
+ // by the length of the interval.
+ if (PhysJoinTweak) {
+ if (SrcIsPhys) {
+ if (!isWinToJoinVRWithSrcPhysReg(CopyMI, CopyMBB, DstInt, SrcInt)) {
+ mri_->setRegAllocationHint(DstInt.reg, 0, SrcReg);
+ ++numAborts;
+ DOUT << "\tMay tie down a physical register, abort!\n";
+ Again = true; // May be possible to coalesce later.
+ return false;
+ }
+ } else {
+ if (!isWinToJoinVRWithDstPhysReg(CopyMI, CopyMBB, DstInt, SrcInt)) {
+ mri_->setRegAllocationHint(SrcInt.reg, 0, DstReg);
+ ++numAborts;
+ DOUT << "\tMay tie down a physical register, abort!\n";
+ Again = true; // May be possible to coalesce later.
+ return false;
+ }
+ }
+ } else {
+ // If the virtual register live interval is long but it has low use desity,
+ // do not join them, instead mark the physical register as its allocation
+ // preference.
+ LiveInterval &JoinVInt = SrcIsPhys ? DstInt : SrcInt;
+ unsigned JoinVReg = SrcIsPhys ? DstReg : SrcReg;
+ unsigned JoinPReg = SrcIsPhys ? SrcReg : DstReg;
+ const TargetRegisterClass *RC = mri_->getRegClass(JoinVReg);
+ unsigned Threshold = allocatableRCRegs_[RC].count() * 2;
+ if (TheCopy.isBackEdge)
+ Threshold *= 2; // Favors back edge copies.
+
+ unsigned Length = li_->getApproximateInstructionCount(JoinVInt);
+ float Ratio = 1.0 / Threshold;
+ if (Length > Threshold &&
+ (((float)std::distance(mri_->use_begin(JoinVReg),
+ mri_->use_end()) / Length) < Ratio)) {
+ mri_->setRegAllocationHint(JoinVInt.reg, 0, JoinPReg);
+ ++numAborts;
+ DOUT << "\tMay tie down a physical register, abort!\n";
+ Again = true; // May be possible to coalesce later.
+ return false;
+ }
}
}
}
if (!isEmpty && !JoinIntervals(DstInt, SrcInt, Swapped)) {
// Coalescing failed.
+
+ // If definition of source is defined by trivial computation, try
+ // rematerializing it.
+ if (!isExtSubReg && !isInsSubReg && !isSubRegToReg &&
+ ReMaterializeTrivialDef(SrcInt, DstInt.reg, CopyMI))
+ return true;
// If we can eliminate the copy without merging the live ranges, do so now.
- if (!isExtSubReg && !isInsSubReg &&
+ if (!isExtSubReg && !isInsSubReg && !isSubRegToReg &&
(AdjustCopiesBackFrom(SrcInt, DstInt, CopyMI) ||
RemoveCopyByCommutingDef(SrcInt, DstInt, CopyMI))) {
JoinedCopies.insert(CopyMI);
assert(TargetRegisterInfo::isVirtualRegister(SrcReg) &&
"LiveInterval::join didn't work right!");
- // If we're about to merge live ranges into a physical register live range,
+ // If we're about to merge live ranges into a physical register live interval,
// we have to update any aliased register's live ranges to indicate that they
// have clobbered values for this range.
if (TargetRegisterInfo::isPhysicalRegister(DstReg)) {
if (RealDstReg || RealSrcReg) {
LiveInterval &RealInt =
li_->getOrCreateInterval(RealDstReg ? RealDstReg : RealSrcReg);
- SmallSet<const VNInfo*, 4> CopiedValNos;
- for (LiveInterval::Ranges::const_iterator I = ResSrcInt->ranges.begin(),
- E = ResSrcInt->ranges.end(); I != E; ++I) {
- const LiveRange *DstLR = ResDstInt->getLiveRangeContaining(I->start);
- assert(DstLR && "Invalid joined interval!");
- const VNInfo *DstValNo = DstLR->valno;
- if (CopiedValNos.insert(DstValNo)) {
- VNInfo *ValNo = RealInt.getNextValue(DstValNo->def, DstValNo->copy,
- li_->getVNInfoAllocator());
- ValNo->hasPHIKill = DstValNo->hasPHIKill;
- RealInt.addKills(ValNo, DstValNo->kills);
- RealInt.MergeValueInAsValue(*ResDstInt, DstValNo, ValNo);
- }
+ for (LiveInterval::const_vni_iterator I = SavedLI->vni_begin(),
+ E = SavedLI->vni_end(); I != E; ++I) {
+ const VNInfo *ValNo = *I;
+ VNInfo *NewValNo = RealInt.getNextValue(ValNo->def, ValNo->copy,
+ false, // updated at *
+ li_->getVNInfoAllocator());
+ NewValNo->setFlags(ValNo->getFlags()); // * updated here.
+ RealInt.addKills(NewValNo, ValNo->kills);
+ RealInt.MergeValueInAsValue(*SavedLI, ValNo, NewValNo);
}
-
+ RealInt.weight += SavedLI->weight;
DstReg = RealDstReg ? RealDstReg : RealSrcReg;
}
for (const unsigned *AS = tri_->getSubRegisters(DstReg); *AS; ++AS)
li_->getOrCreateInterval(*AS).MergeInClobberRanges(*ResSrcInt,
li_->getVNInfoAllocator());
- } else {
- // Merge use info if the destination is a virtual register.
- LiveVariables::VarInfo& dVI = lv_->getVarInfo(DstReg);
- LiveVariables::VarInfo& sVI = lv_->getVarInfo(SrcReg);
- dVI.NumUses += sVI.NumUses;
}
// If this is a EXTRACT_SUBREG, make sure the result of coalescing is the
// larger super-register.
- if ((isExtSubReg || isInsSubReg) && !SrcIsPhys && !DstIsPhys) {
- if ((isExtSubReg && !Swapped) || (isInsSubReg && Swapped)) {
- ResSrcInt->Copy(*ResDstInt, li_->getVNInfoAllocator());
+ if ((isExtSubReg || isInsSubReg || isSubRegToReg) &&
+ !SrcIsPhys && !DstIsPhys) {
+ if ((isExtSubReg && !Swapped) ||
+ ((isInsSubReg || isSubRegToReg) && Swapped)) {
+ ResSrcInt->Copy(*ResDstInt, mri_, li_->getVNInfoAllocator());
std::swap(SrcReg, DstReg);
std::swap(ResSrcInt, ResDstInt);
}
}
+ // Coalescing to a virtual register that is of a sub-register class of the
+ // other. Make sure the resulting register is set to the right register class.
+ if (CrossRC) {
+ ++numCrossRCs;
+ if (NewRC)
+ mri_->setRegClass(DstReg, NewRC);
+ }
+
if (NewHeuristic) {
// Add all copies that define val# in the source interval into the queue.
for (LiveInterval::const_vni_iterator i = ResSrcInt->vni_begin(),
e = ResSrcInt->vni_end(); i != e; ++i) {
const VNInfo *vni = *i;
- if (!vni->def || vni->def == ~1U || vni->def == ~0U)
+ // FIXME: Do isPHIDef and isDefAccurate both need to be tested?
+ if (!vni->def || vni->isUnused() || vni->isPHIDef() || !vni->isDefAccurate())
continue;
MachineInstr *CopyMI = li_->getInstructionFromIndex(vni->def);
- unsigned NewSrcReg, NewDstReg;
+ unsigned NewSrcReg, NewDstReg, NewSrcSubIdx, NewDstSubIdx;
if (CopyMI &&
JoinedCopies.count(CopyMI) == 0 &&
- tii_->isMoveInstr(*CopyMI, NewSrcReg, NewDstReg)) {
- unsigned LoopDepth = loopInfo->getLoopDepth(CopyMI->getParent());
+ tii_->isMoveInstr(*CopyMI, NewSrcReg, NewDstReg,
+ NewSrcSubIdx, NewDstSubIdx)) {
+ unsigned LoopDepth = loopInfo->getLoopDepth(CopyMBB);
JoinQueue->push(CopyRec(CopyMI, LoopDepth,
isBackEdgeCopy(CopyMI, DstReg)));
}
if (TargetRegisterInfo::isVirtualRegister(DstReg))
RemoveUnnecessaryKills(DstReg, *ResDstInt);
- // SrcReg is guarateed to be the register whose live interval that is
- // being merged.
- li_->removeInterval(SrcReg);
if (isInsSubReg)
// Avoid:
// r1024 = op
RemoveDeadImpDef(DstReg, *ResDstInt);
UpdateRegDefsUses(SrcReg, DstReg, SubIdx);
+ // SrcReg is guarateed to be the register whose live interval that is
+ // being merged.
+ li_->removeInterval(SrcReg);
+
+ // Update regalloc hint.
+ tri_->UpdateRegAllocHint(SrcReg, DstReg, *mf_);
+
+ // Manually deleted the live interval copy.
+ if (SavedLI) {
+ SavedLI->clear();
+ delete SavedLI;
+ }
+
if (isEmpty) {
// Now the copy is being coalesced away, the val# previously defined
// by the copy is being defined by an IMPLICIT_DEF which defines a zero
VNInfo *ImpVal = LR->valno;
assert(ImpVal->def == CopyIdx);
unsigned NextDef = LR->end;
- RemoveCopiesFromValNo(*ResDstInt, ImpVal);
+ TurnCopiesFromValNoToImpDefs(*ResDstInt, ImpVal);
ResDstInt->removeValNo(ImpVal);
LR = ResDstInt->FindLiveRangeContaining(NextDef);
if (LR != ResDstInt->end() && LR->valno->def == NextDef) {
}
}
+ // If resulting interval has a preference that no longer fits because of subreg
+ // coalescing, just clear the preference.
+ unsigned Preference = getRegAllocPreference(ResDstInt->reg, *mf_, mri_, tri_);
+ if (Preference && (isExtSubReg || isInsSubReg || isSubRegToReg) &&
+ TargetRegisterInfo::isVirtualRegister(ResDstInt->reg)) {
+ const TargetRegisterClass *RC = mri_->getRegClass(ResDstInt->reg);
+ if (!RC->contains(Preference))
+ mri_->setRegAllocationHint(ResDstInt->reg, 0, 0);
+ }
+
DOUT << "\n\t\tJoined. Result = "; ResDstInt->print(DOUT, tri_);
DOUT << "\n";
unsigned SrcReg = li_->getVNInfoSourceReg(LR->valno);
if (SrcReg == Reg)
return true;
- if (LR->valno->def == ~0U &&
+ // FIXME: Do isPHIDef and isDefAccurate both need to be tested?
+ if ((LR->valno->isPHIDef() || !LR->valno->isDefAccurate()) &&
TargetRegisterInfo::isPhysicalRegister(li.reg) &&
*tri_->getSuperRegisters(li.reg)) {
// It's a sub-register live interval, we may not have precise information.
// Re-compute it.
MachineInstr *DefMI = li_->getInstructionFromIndex(LR->start);
- unsigned SrcReg, DstReg;
- if (tii_->isMoveInstr(*DefMI, SrcReg, DstReg) &&
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (DefMI &&
+ tii_->isMoveInstr(*DefMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
DstReg == li.reg && SrcReg == Reg) {
// Cache computed info.
LR->valno->def = LR->start;
// Copy from the RHS?
if (!RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg))
return false; // Nope, bail out.
-
+
+ if (LHSIt->contains(RHSIt->valno->def))
+ // Here is an interesting situation:
+ // BB1:
+ // vr1025 = copy vr1024
+ // ..
+ // BB2:
+ // vr1024 = op
+ // = vr1025
+ // Even though vr1025 is copied from vr1024, it's not safe to
+ // coalesce them since the live range of vr1025 intersects the
+ // def of vr1024. This happens because vr1025 is assigned the
+ // value of the previous iteration of vr1024.
+ return false;
EliminatedLHSVals.push_back(LHSIt->valno);
}
// Otherwise, if this is a copy from the RHS, mark it as being merged
// in.
if (RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg)) {
+ if (LHSIt->contains(RHSIt->valno->def))
+ // Here is an interesting situation:
+ // BB1:
+ // vr1025 = copy vr1024
+ // ..
+ // BB2:
+ // vr1024 = op
+ // = vr1025
+ // Even though vr1025 is copied from vr1024, it's not safe to
+ // coalesced them since live range of vr1025 intersects the
+ // def of vr1024. This happens because vr1025 is assigned the
+ // value of the previous iteration of vr1024.
+ return false;
EliminatedLHSVals.push_back(LHSIt->valno);
// We know this entire LHS live range is okay, so skip it now.
// optimize for it: if there is more than one value, we merge them all into
// the lowest numbered one, then handle the interval as if we were merging
// with one value number.
- VNInfo *LHSValNo;
+ VNInfo *LHSValNo = NULL;
if (EliminatedLHSVals.size() > 1) {
// Loop through all the equal value numbers merging them into the smallest
// one.
// Okay, the final step is to loop over the RHS live intervals, adding them to
// the LHS.
- LHSValNo->hasPHIKill |= VNI->hasPHIKill;
+ if (VNI->hasPHIKill())
+ LHSValNo->setHasPHIKill(true);
LHS.addKills(LHSValNo, VNI->kills);
LHS.MergeRangesInAsValue(RHS, LHSValNo);
LHS.weight += RHS.weight;
- if (RHS.preference && !LHS.preference)
- LHS.preference = RHS.preference;
-
+
+ // Update regalloc hint if both are virtual registers.
+ if (TargetRegisterInfo::isVirtualRegister(LHS.reg) &&
+ TargetRegisterInfo::isVirtualRegister(RHS.reg)) {
+ std::pair<unsigned, unsigned> RHSPref = mri_->getRegAllocationHint(RHS.reg);
+ std::pair<unsigned, unsigned> LHSPref = mri_->getRegAllocationHint(LHS.reg);
+ if (RHSPref != LHSPref)
+ mri_->setRegAllocationHint(LHS.reg, RHSPref.first, RHSPref.second);
+ }
+
+ // Update the liveintervals of sub-registers.
+ if (TargetRegisterInfo::isPhysicalRegister(LHS.reg))
+ for (const unsigned *AS = tri_->getSubRegisters(LHS.reg); *AS; ++AS)
+ li_->getOrCreateInterval(*AS).MergeInClobberRanges(LHS,
+ li_->getVNInfoAllocator());
+
return true;
}
/// physreg, this method always canonicalizes LHS to be it. The output
/// "RHS" will not have been modified, so we can use this information
/// below to update aliases.
-bool SimpleRegisterCoalescing::JoinIntervals(LiveInterval &LHS,
- LiveInterval &RHS, bool &Swapped) {
+bool
+SimpleRegisterCoalescing::JoinIntervals(LiveInterval &LHS, LiveInterval &RHS,
+ bool &Swapped) {
// Compute the final value assignment, assuming that the live ranges can be
// coalesced.
SmallVector<int, 16> LHSValNoAssignments;
DenseMap<VNInfo*, VNInfo*> LHSValsDefinedFromRHS;
DenseMap<VNInfo*, VNInfo*> RHSValsDefinedFromLHS;
SmallVector<VNInfo*, 16> NewVNInfo;
-
+
// If a live interval is a physical register, conservatively check if any
// of its sub-registers is overlapping the live interval of the virtual
// register. If so, do not coalesce.
if (TargetRegisterInfo::isPhysicalRegister(LHS.reg) &&
*tri_->getSubRegisters(LHS.reg)) {
- for (const unsigned* SR = tri_->getSubRegisters(LHS.reg); *SR; ++SR)
- if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) {
- DOUT << "Interfere with sub-register ";
- DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ // If it's coalescing a virtual register to a physical register, estimate
+ // its live interval length. This is the *cost* of scanning an entire live
+ // interval. If the cost is low, we'll do an exhaustive check instead.
+
+ // If this is something like this:
+ // BB1:
+ // v1024 = op
+ // ...
+ // BB2:
+ // ...
+ // RAX = v1024
+ //
+ // That is, the live interval of v1024 crosses a bb. Then we can't rely on
+ // less conservative check. It's possible a sub-register is defined before
+ // v1024 (or live in) and live out of BB1.
+ if (RHS.containsOneValue() &&
+ li_->intervalIsInOneMBB(RHS) &&
+ li_->getApproximateInstructionCount(RHS) <= 10) {
+ // Perform a more exhaustive check for some common cases.
+ if (li_->conflictsWithPhysRegRef(RHS, LHS.reg, true, JoinedCopies))
return false;
- }
+ } else {
+ for (const unsigned* SR = tri_->getSubRegisters(LHS.reg); *SR; ++SR)
+ if (li_->hasInterval(*SR) && RHS.overlaps(li_->getInterval(*SR))) {
+ DOUT << "Interfere with sub-register ";
+ DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ return false;
+ }
+ }
} else if (TargetRegisterInfo::isPhysicalRegister(RHS.reg) &&
*tri_->getSubRegisters(RHS.reg)) {
- for (const unsigned* SR = tri_->getSubRegisters(RHS.reg); *SR; ++SR)
- if (li_->hasInterval(*SR) && LHS.overlaps(li_->getInterval(*SR))) {
- DOUT << "Interfere with sub-register ";
- DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ if (LHS.containsOneValue() &&
+ li_->getApproximateInstructionCount(LHS) <= 10) {
+ // Perform a more exhaustive check for some common cases.
+ if (li_->conflictsWithPhysRegRef(LHS, RHS.reg, false, JoinedCopies))
return false;
- }
+ } else {
+ for (const unsigned* SR = tri_->getSubRegisters(RHS.reg); *SR; ++SR)
+ if (li_->hasInterval(*SR) && LHS.overlaps(li_->getInterval(*SR))) {
+ DOUT << "Interfere with sub-register ";
+ DEBUG(li_->getInterval(*SR).print(DOUT, tri_));
+ return false;
+ }
+ }
}
// Compute ultimate value numbers for the LHS and RHS values.
VNInfo *RHSValNoInfo = NULL;
VNInfo *RHSValNoInfo0 = RHS.getValNumInfo(0);
unsigned RHSSrcReg = li_->getVNInfoSourceReg(RHSValNoInfo0);
- if ((RHSSrcReg == 0 || RHSSrcReg != LHS.reg)) {
+ if (RHSSrcReg == 0 || RHSSrcReg != LHS.reg) {
// If RHS is not defined as a copy from the LHS, we can use simpler and
// faster checks to see if the live ranges are coalescable. This joiner
// can't swap the LHS/RHS intervals though.
for (LiveInterval::vni_iterator i = LHS.vni_begin(), e = LHS.vni_end();
i != e; ++i) {
VNInfo *VNI = *i;
- if (VNI->def == ~1U || VNI->copy == 0) // Src not defined by a copy?
+ if (VNI->isUnused() || VNI->copy == 0) // Src not defined by a copy?
continue;
// DstReg is known to be a register in the LHS interval. If the src is
for (LiveInterval::vni_iterator i = RHS.vni_begin(), e = RHS.vni_end();
i != e; ++i) {
VNInfo *VNI = *i;
- if (VNI->def == ~1U || VNI->copy == 0) // Src not defined by a copy?
+ if (VNI->isUnused() || VNI->copy == 0) // Src not defined by a copy?
continue;
// DstReg is known to be a register in the RHS interval. If the src is
i != e; ++i) {
VNInfo *VNI = *i;
unsigned VN = VNI->id;
- if (LHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
+ if (LHSValNoAssignments[VN] >= 0 || VNI->isUnused())
continue;
ComputeUltimateVN(VNI, NewVNInfo,
LHSValsDefinedFromRHS, RHSValsDefinedFromLHS,
i != e; ++i) {
VNInfo *VNI = *i;
unsigned VN = VNI->id;
- if (RHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
+ if (RHSValNoAssignments[VN] >= 0 || VNI->isUnused())
continue;
// If this value number isn't a copy from the LHS, it's a new number.
if (RHSValsDefinedFromLHS.find(VNI) == RHSValsDefinedFromLHS.end()) {
VNInfo *VNI = I->first;
unsigned LHSValID = LHSValNoAssignments[VNI->id];
LiveInterval::removeKill(NewVNInfo[LHSValID], VNI->def);
- NewVNInfo[LHSValID]->hasPHIKill |= VNI->hasPHIKill;
+ if (VNI->hasPHIKill())
+ NewVNInfo[LHSValID]->setHasPHIKill(true);
RHS.addKills(NewVNInfo[LHSValID], VNI->kills);
}
VNInfo *VNI = I->first;
unsigned RHSValID = RHSValNoAssignments[VNI->id];
LiveInterval::removeKill(NewVNInfo[RHSValID], VNI->def);
- NewVNInfo[RHSValID]->hasPHIKill |= VNI->hasPHIKill;
+ if (VNI->hasPHIKill())
+ NewVNInfo[RHSValID]->setHasPHIKill(true);
LHS.addKills(NewVNInfo[RHSValID], VNI->kills);
}
if ((RHS.ranges.size() > LHS.ranges.size() &&
TargetRegisterInfo::isVirtualRegister(LHS.reg)) ||
TargetRegisterInfo::isPhysicalRegister(RHS.reg)) {
- RHS.join(LHS, &RHSValNoAssignments[0], &LHSValNoAssignments[0], NewVNInfo);
+ RHS.join(LHS, &RHSValNoAssignments[0], &LHSValNoAssignments[0], NewVNInfo,
+ mri_);
Swapped = true;
} else {
- LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo);
+ LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo,
+ mri_);
Swapped = false;
}
return true;
MachineInstr *Inst = MII++;
// If this isn't a copy nor a extract_subreg, we can't join intervals.
- unsigned SrcReg, DstReg;
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
if (Inst->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG) {
DstReg = Inst->getOperand(0).getReg();
SrcReg = Inst->getOperand(1).getReg();
- } else if (Inst->getOpcode() == TargetInstrInfo::INSERT_SUBREG) {
+ } else if (Inst->getOpcode() == TargetInstrInfo::INSERT_SUBREG ||
+ Inst->getOpcode() == TargetInstrInfo::SUBREG_TO_REG) {
DstReg = Inst->getOperand(0).getReg();
SrcReg = Inst->getOperand(2).getReg();
- } else if (!tii_->isMoveInstr(*Inst, SrcReg, DstReg))
+ } else if (!tii_->isMoveInstr(*Inst, SrcReg, DstReg, SrcSubIdx, DstSubIdx))
continue;
bool SrcIsPhys = TargetRegisterInfo::isPhysicalRegister(SrcReg);
JoinQueue = new JoinPriorityQueue<CopyRecSort>(this);
std::vector<CopyRec> TryAgainList;
- if (loopInfo->begin() == loopInfo->end()) {
+ if (loopInfo->empty()) {
// If there are no loops in the function, join intervals in function order.
for (MachineFunction::iterator I = mf_->begin(), E = mf_->end();
I != E; ++I)
/// Return true if the two specified registers belong to different register
/// classes. The registers may be either phys or virt regs.
-bool SimpleRegisterCoalescing::differingRegisterClasses(unsigned RegA,
- unsigned RegB) const {
-
+bool
+SimpleRegisterCoalescing::differingRegisterClasses(unsigned RegA,
+ unsigned RegB) const {
// Get the register classes for the first reg.
if (TargetRegisterInfo::isPhysicalRegister(RegA)) {
assert(TargetRegisterInfo::isVirtualRegister(RegB) &&
}
// Compare against the regclass for the second reg.
- const TargetRegisterClass *RegClass = mri_->getRegClass(RegA);
- if (TargetRegisterInfo::isVirtualRegister(RegB))
- return RegClass != mri_->getRegClass(RegB);
- else
- return !RegClass->contains(RegB);
+ const TargetRegisterClass *RegClassA = mri_->getRegClass(RegA);
+ if (TargetRegisterInfo::isVirtualRegister(RegB)) {
+ const TargetRegisterClass *RegClassB = mri_->getRegClass(RegB);
+ return RegClassA != RegClassB;
+ }
+ return !RegClassA->contains(RegB);
}
/// lastRegisterUse - Returns the last use of the specific register between
E = mri_->use_end(); I != E; ++I) {
MachineOperand &Use = I.getOperand();
MachineInstr *UseMI = Use.getParent();
- unsigned SrcReg, DstReg;
- if (tii_->isMoveInstr(*UseMI, SrcReg, DstReg) && SrcReg == DstReg)
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (tii_->isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
+ SrcReg == DstReg)
// Ignore identity copies.
continue;
unsigned Idx = li_->getInstructionIndex(UseMI);
if (Idx >= Start && Idx < End && Idx >= UseIdx) {
LastUse = &Use;
- UseIdx = Idx;
+ UseIdx = li_->getUseIndex(Idx);
}
}
return LastUse;
return NULL;
// Ignore identity copies.
- unsigned SrcReg, DstReg;
- if (!(tii_->isMoveInstr(*MI, SrcReg, DstReg) && SrcReg == DstReg))
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (!(tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
+ SrcReg == DstReg))
for (unsigned i = 0, NumOps = MI->getNumOperands(); i != NumOps; ++i) {
MachineOperand &Use = MI->getOperand(i);
- if (Use.isRegister() && Use.isUse() && Use.getReg() &&
+ if (Use.isReg() && Use.isUse() && Use.getReg() &&
tri_->regsOverlap(Use.getReg(), Reg)) {
- UseIdx = e;
+ UseIdx = li_->getUseIndex(e);
return &Use;
}
}
void SimpleRegisterCoalescing::releaseMemory() {
JoinedCopies.clear();
+ ReMatCopies.clear();
+ ReMatDefs.clear();
}
static bool isZeroLengthInterval(LiveInterval *li) {
for (LiveInterval::Ranges::const_iterator
i = li->ranges.begin(), e = li->ranges.end(); i != e; ++i)
- if (i->end - i->start > LiveIntervals::InstrSlots::NUM)
+ if (i->end - i->start > LiveInterval::InstrSlots::NUM)
return false;
return true;
}
return false;
LiveInterval &DstInt = li_->getInterval(DstReg);
const LiveRange *DstLR = DstInt.getLiveRangeContaining(CopyIdx);
+ // If the valno extends beyond this basic block, then it's not safe to delete
+ // the val# or else livein information won't be correct.
+ MachineBasicBlock *EndMBB = li_->getMBBFromIndex(DstLR->end);
+ if (EndMBB != MBB)
+ return false;
DstInt.removeValNo(DstLR->valno);
CopyMI->setDesc(tii_->get(TargetInstrInfo::IMPLICIT_DEF));
for (int i = CopyMI->getNumOperands() - 1, e = 0; i > e; --i)
CopyMI->RemoveOperand(i);
- bool NoUse = mri_->use_begin(SrcReg) == mri_->use_end();
+ CopyMI->getOperand(0).setIsUndef();
+ bool NoUse = mri_->use_empty(SrcReg);
if (NoUse) {
- for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(SrcReg),
- E = mri_->reg_end(); I != E; ) {
- assert(I.getOperand().isDef());
- MachineInstr *DefMI = &*I;
- ++I;
+ for (MachineRegisterInfo::reg_iterator RI = mri_->reg_begin(SrcReg),
+ RE = mri_->reg_end(); RI != RE; ) {
+ assert(RI.getOperand().isDef());
+ MachineInstr *DefMI = &*RI;
+ ++RI;
// The implicit_def source has no other uses, delete it.
assert(DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF);
li_->RemoveMachineInstrFromMaps(DefMI);
DefMI->eraseFromParent();
}
}
+
+ // Mark uses of implicit_def isUndef.
+ for (MachineRegisterInfo::use_iterator RI = mri_->use_begin(DstReg),
+ RE = mri_->use_end(); RI != RE; ++RI) {
+ assert((*RI).getParent() == MBB);
+ RI.getOperand().setIsUndef();
+ }
+
++I;
return true;
}
tri_ = tm_->getRegisterInfo();
tii_ = tm_->getInstrInfo();
li_ = &getAnalysis<LiveIntervals>();
- lv_ = &getAnalysis<LiveVariables>();
loopInfo = &getAnalysis<MachineLoopInfo>();
DOUT << "********** SIMPLE REGISTER COALESCING **********\n"
// Join (coalesce) intervals if requested.
if (EnableJoining) {
joinIntervals();
- DOUT << "********** INTERVALS POST JOINING **********\n";
- for (LiveIntervals::iterator I = li_->begin(), E = li_->end(); I != E; ++I){
- I->second.print(DOUT, tri_);
- DOUT << "\n";
- }
-
- // Delete all coalesced copies.
- for (SmallPtrSet<MachineInstr*,32>::iterator I = JoinedCopies.begin(),
- E = JoinedCopies.end(); I != E; ++I) {
- MachineInstr *CopyMI = *I;
- unsigned SrcReg, DstReg;
- if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg)) {
- assert((CopyMI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG ||
- CopyMI->getOpcode() == TargetInstrInfo::INSERT_SUBREG) &&
- "Unrecognized copy instruction");
- DstReg = CopyMI->getOperand(0).getReg();
- }
- if (CopyMI->registerDefIsDead(DstReg)) {
- LiveInterval &li = li_->getInterval(DstReg);
- if (!ShortenDeadCopySrcLiveRange(li, CopyMI))
- ShortenDeadCopyLiveRange(li, CopyMI);
- }
- li_->RemoveMachineInstrFromMaps(*I);
- (*I)->eraseFromParent();
- ++numPeep;
- }
+ DEBUG({
+ DOUT << "********** INTERVALS POST JOINING **********\n";
+ for (LiveIntervals::iterator I = li_->begin(), E = li_->end(); I != E; ++I){
+ I->second->print(DOUT, tri_);
+ DOUT << "\n";
+ }
+ });
}
// Perform a final pass over the instructions and compute spill weights
// and remove identity moves.
+ SmallVector<unsigned, 4> DeadDefs;
for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
mbbi != mbbe; ++mbbi) {
MachineBasicBlock* mbb = mbbi;
for (MachineBasicBlock::iterator mii = mbb->begin(), mie = mbb->end();
mii != mie; ) {
- // if the move will be an identity move delete it
- unsigned srcReg, dstReg;
- bool isMove = tii_->isMoveInstr(*mii, srcReg, dstReg);
- if (isMove && srcReg == dstReg) {
- if (li_->hasInterval(srcReg)) {
- LiveInterval &RegInt = li_->getInterval(srcReg);
+ MachineInstr *MI = mii;
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (JoinedCopies.count(MI)) {
+ // Delete all coalesced copies.
+ if (!tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)) {
+ assert((MI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG ||
+ MI->getOpcode() == TargetInstrInfo::INSERT_SUBREG ||
+ MI->getOpcode() == TargetInstrInfo::SUBREG_TO_REG) &&
+ "Unrecognized copy instruction");
+ DstReg = MI->getOperand(0).getReg();
+ }
+ if (MI->registerDefIsDead(DstReg)) {
+ LiveInterval &li = li_->getInterval(DstReg);
+ if (!ShortenDeadCopySrcLiveRange(li, MI))
+ ShortenDeadCopyLiveRange(li, MI);
+ }
+ li_->RemoveMachineInstrFromMaps(MI);
+ mii = mbbi->erase(mii);
+ ++numPeep;
+ continue;
+ }
+
+ // Now check if this is a remat'ed def instruction which is now dead.
+ if (ReMatDefs.count(MI)) {
+ bool isDead = true;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg)
+ continue;
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ DeadDefs.push_back(Reg);
+ if (MO.isDead())
+ continue;
+ if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
+ !mri_->use_empty(Reg)) {
+ isDead = false;
+ break;
+ }
+ }
+ if (isDead) {
+ while (!DeadDefs.empty()) {
+ unsigned DeadDef = DeadDefs.back();
+ DeadDefs.pop_back();
+ RemoveDeadDef(li_->getInterval(DeadDef), MI);
+ }
+ li_->RemoveMachineInstrFromMaps(mii);
+ mii = mbbi->erase(mii);
+ continue;
+ } else
+ DeadDefs.clear();
+ }
+
+ // If the move will be an identity move delete it
+ bool isMove= tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx);
+ if (isMove && SrcReg == DstReg) {
+ if (li_->hasInterval(SrcReg)) {
+ LiveInterval &RegInt = li_->getInterval(SrcReg);
// If def of this move instruction is dead, remove its live range
// from the dstination register's live interval.
- if (mii->registerDefIsDead(dstReg)) {
- if (!ShortenDeadCopySrcLiveRange(RegInt, mii))
- ShortenDeadCopyLiveRange(RegInt, mii);
+ if (MI->registerDefIsDead(DstReg)) {
+ if (!ShortenDeadCopySrcLiveRange(RegInt, MI))
+ ShortenDeadCopyLiveRange(RegInt, MI);
}
}
- li_->RemoveMachineInstrFromMaps(mii);
+ li_->RemoveMachineInstrFromMaps(MI);
mii = mbbi->erase(mii);
++numPeep;
- } else if (!isMove || !TurnCopyIntoImpDef(mii, mbb, dstReg, srcReg)) {
+ } else if (!isMove || !TurnCopyIntoImpDef(mii, mbb, DstReg, SrcReg)) {
SmallSet<unsigned, 4> UniqueUses;
- for (unsigned i = 0, e = mii->getNumOperands(); i != e; ++i) {
- const MachineOperand &mop = mii->getOperand(i);
- if (mop.isRegister() && mop.getReg() &&
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &mop = MI->getOperand(i);
+ if (mop.isReg() && mop.getReg() &&
TargetRegisterInfo::isVirtualRegister(mop.getReg())) {
unsigned reg = mop.getReg();
// Multiple uses of reg by the same instruction. It should not
}
for (LiveIntervals::iterator I = li_->begin(), E = li_->end(); I != E; ++I) {
- LiveInterval &LI = I->second;
+ LiveInterval &LI = *I->second;
if (TargetRegisterInfo::isVirtualRegister(LI.reg)) {
// If the live interval length is essentially zero, i.e. in every live
// range the use follows def immediately, it doesn't make sense to spill
LI.weight = HUGE_VALF;
else {
bool isLoad = false;
- if (li_->isReMaterializable(LI, isLoad)) {
+ SmallVector<LiveInterval*, 4> SpillIs;
+ if (li_->isReMaterializable(LI, SpillIs, isLoad)) {
// If all of the definitions of the interval are re-materializable,
// it is a preferred candidate for spilling. If non of the defs are
// loads, then it's potentially very cheap to re-materialize.
}
// Slightly prefer live interval that has been assigned a preferred reg.
- if (LI.preference)
+ std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(LI.reg);
+ if (Hint.first || Hint.second)
LI.weight *= 1.01F;
// Divide the weight of the interval by its size. This encourages
// spilling of intervals that are large and have few uses, and
// discourages spilling of small intervals with many uses.
- LI.weight /= LI.getSize();
+ LI.weight /= li_->getApproximateInstructionCount(LI) * InstrSlots::NUM;
}
}
projects / oota-llvm.git / blobdiff