using namespace llvm;
STATISTIC(numJoins , "Number of interval joins performed");
-STATISTIC(numSubJoins , "Number of subclass 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");
cl::init(false), cl::Hidden);
static cl::opt<bool>
-CrossClassJoin("join-subclass-copies",
- cl::desc("Coalesce copies to sub- register class"),
+CrossClassJoin("join-cross-class-copies",
+ cl::desc("Coalesce cross register class copies"),
cl::init(false), cl::Hidden);
static RegisterPass<SimpleRegisterCoalescing>
// 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.
// 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.
// 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.
else
BKills.push_back(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#,
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 ive 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_);
+ 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,
MachineInstr *CopyMI) {
unsigned CopyIdx = li_->getUseIndex(li_->getInstructionIndex(CopyMI));
LiveInterval::iterator SrcLR = SrcInt.FindLiveRangeContaining(CopyIdx);
- if (SrcLR == SrcInt.end()) // Should never happen!
- return false;
+ 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.
}
}
+ // If copy kills the source register, find the last use and propagate
+ // kill.
MachineBasicBlock *MBB = CopyMI->getParent();
+ if (CopyMI->killsRegister(SrcInt.reg))
+ TrimLiveIntervalToLastUse(CopyIdx, MBB, SrcInt, SrcLR);
+
MachineBasicBlock::iterator MII = next(MachineBasicBlock::iterator(CopyMI));
CopyMI->removeFromParent();
tii_->reMaterialize(*MBB, MII, DstReg, DefMI);
if (OldSubIdx)
UseDstReg = tri_->getSubReg(DstReg, OldSubIdx);
- unsigned CopySrcReg, CopyDstReg;
- if (tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg) &&
+ 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
// After updating the operand, check if the machine instruction has
// become a copy. If so, update its val# information.
const TargetInstrDesc &TID = UseMI->getDesc();
- unsigned CopySrcReg, CopyDstReg;
+ unsigned CopySrcReg, CopyDstReg, CopySrcSubIdx, CopyDstSubIdx;
if (TID.getNumDefs() == 1 && TID.getNumOperands() > 2 &&
- tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg) &&
+ tii_->isMoveInstr(*UseMI, CopySrcReg, CopyDstReg,
+ CopySrcSubIdx, CopyDstSubIdx) &&
CopySrcReg != CopyDstReg &&
(TargetRegisterInfo::isVirtualRegister(CopyDstReg) ||
allocatableRegs_[CopyDstReg])) {
}
}
-/// 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.
}
}
-/// 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);
-}
-
/// ShortenDeadCopySrcLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill as
/// ends the live range there. If there isn't another use, then this live range
// More uses past this copy? Nothing to do.
return false;
- MachineBasicBlock *CopyMBB = CopyMI->getParent();
- 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 false;
- }
-
- // 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_);
- 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.
+ if (TrimLiveIntervalToLastUse(CopyIdx, CopyMI->getParent(), li, LR))
return false;
- }
-
- // 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.
- }
if (LR->valno->def == RemoveStart)
// If the def MI defines the val#, propagate the dead marker.
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;
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) {
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
+ if (tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx) &&
+ 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);
return 0;
}
-/// isProfitableToCoalesceToSubRC - Given that register class of DstReg is
-/// a subset of the register class of SrcReg, return true if it's profitable
-/// to coalesce the two registers.
+/// isWinToJoinCrossClass - Return true if it's profitable to coalesce
+/// two virtual registers from different register classes.
bool
-SimpleRegisterCoalescing::isProfitableToCoalesceToSubRC(unsigned SrcReg,
- unsigned DstReg,
- MachineBasicBlock *MBB){
- if (!CrossClassJoin)
- return false;
-
- // First let's make sure all uses are in the same MBB.
- for (MachineRegisterInfo::reg_iterator RI = mri_->reg_begin(SrcReg),
- RE = mri_->reg_end(); RI != RE; ++RI) {
- MachineInstr &MI = *RI;
- if (MI.getParent() != MBB)
- return false;
- }
- for (MachineRegisterInfo::reg_iterator RI = mri_->reg_begin(DstReg),
- RE = mri_->reg_end(); RI != RE; ++RI) {
- MachineInstr &MI = *RI;
- if (MI.getParent() != MBB)
- return false;
- }
-
+SimpleRegisterCoalescing::isWinToJoinCrossClass(unsigned LargeReg,
+ unsigned SmallReg,
+ unsigned Threshold) {
// Then make sure the intervals are *short*.
- LiveInterval &SrcInt = li_->getInterval(SrcReg);
- LiveInterval &DstInt = li_->getInterval(DstReg);
- unsigned SrcSize = li_->getApproximateInstructionCount(SrcInt);
- unsigned DstSize = li_->getApproximateInstructionCount(DstInt);
- const TargetRegisterClass *RC = mri_->getRegClass(DstReg);
- unsigned Threshold = allocatableRCRegs_[RC].count() * 2;
- return (SrcSize + DstSize) <= Threshold;
+ 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
}
+/// 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 = getMatchingSuperReg(DstReg, SubIdx, RC, tri_);
+ 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 = getMatchingSuperReg(SrcReg, SubIdx, RC, tri_);
+ 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;
+}
+
/// JoinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
/// which are the src/dst of the copy instruction CopyMI. This returns true
/// if the copy was successfully coalesced away. If it is not currently
DOUT << li_->getInstructionIndex(CopyMI) << '\t' << *CopyMI;
- unsigned SrcReg;
- unsigned DstReg;
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
bool isExtSubReg = CopyMI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG;
bool isInsSubReg = CopyMI->getOpcode() == TargetInstrInfo::INSERT_SUBREG;
unsigned SubIdx = 0;
}
DstReg = CopyMI->getOperand(0).getReg();
SrcReg = CopyMI->getOperand(2).getReg();
- } else if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg)) {
+ } else if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)){
assert(0 && "Unrecognized copy instruction!");
return false;
}
}
// Should be non-null only when coalescing to a sub-register class.
- const TargetRegisterClass *SubRC = NULL;
+ bool CrossRC = false;
+ const TargetRegisterClass *NewRC = NULL;
MachineBasicBlock *CopyMBB = CopyMI->getParent();
unsigned RealDstReg = 0;
unsigned RealSrcReg = 0;
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"
+ 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 extract_subreg instruction!");
+ if (!CanJoinExtractSubRegToPhysReg(DstReg, SrcReg, SubIdx, RealDstReg))
+ return false; // Not coalescable
} else {
- RealSrcReg = getMatchingSuperReg(SrcReg, SubIdx, RC, tri_);
- assert(RealSrcReg && "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.
- 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 &&
- !differingRegisterClasses(SrcReg, DstReg, SubRC))
+ 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
if (SubIdx) {
unsigned LargeReg = isExtSubReg ? SrcReg : DstReg;
unsigned SmallReg = isExtSubReg ? DstReg : SrcReg;
- unsigned LargeRegSize =
- li_->getApproximateInstructionCount(li_->getInterval(LargeReg));
- unsigned SmallRegSize =
- li_->getApproximateInstructionCount(li_->getInterval(SmallReg));
- 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) {
- if ((float)std::distance(mri_->use_begin(SmallReg),
- mri_->use_end()) / SmallRegSize <
- (float)std::distance(mri_->use_begin(LargeReg),
- mri_->use_end()) / 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, SubRC)) {
- // FIXME: What if the resul of a EXTRACT_SUBREG is then coalesced
+ } else if (differingRegisterClasses(SrcReg, DstReg)) {
+ 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 (!SubRC || !isProfitableToCoalesceToSubRC(SrcReg, DstReg, CopyMBB)) {
- // If they are not of the same register class, we cannot join them.
+ // Process moves where one of the registers have a sub-register index.
+ MachineOperand *DstMO = CopyMI->findRegisterDefOperand(DstReg);
+ if (DstMO->getSubReg())
+ // FIXME: Can we handle this?
+ return false;
+ MachineOperand *SrcMO = CopyMI->findRegisterUseOperand(SrcReg);
+ SubIdx = SrcMO->getSubReg();
+ if (SubIdx) {
+ // This is not a extract_subreg but it looks like one.
+ // e.g. %cl = MOV16rr %reg1024:2
+ 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 && !SrcIsPhys) {
+ unsigned SrcSize = SrcRC->getSize();
+ unsigned DstSize = DstRC->getSize();
+ if (SrcSize < DstSize)
+ // For example X86::MOVSD2PDrr copies from FR64 to VR128.
+ NewRC = DstRC;
+ else if (DstSize > SrcSize) {
+ NewRC = SrcRC;
+ std::swap(LargeReg, SmallReg);
+ } else {
+ unsigned SrcNumRegs = SrcRC->getNumRegs();
+ unsigned DstNumRegs = DstRC->getNumRegs();
+ if (DstNumRegs < SrcNumRegs)
+ // Sub-register class?
+ NewRC = DstRC;
+ else if (SrcNumRegs < DstNumRegs) {
+ NewRC = SrcRC;
+ std::swap(LargeReg, SmallReg);
+ } else
+ // No idea what's the right register class to use.
+ return false;
+ }
+ }
+
+ // 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.
+ // But later r1024 is assigned EAX then r1025 may be coalesced with EAX.
Again = true; // May be possible to coalesce later.
return false;
}
// 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 (SubRC) {
- mri_->setRegClass(DstReg, SubRC);
- ++numSubJoins;
+ if (CrossRC) {
+ ++numCrossRCs;
+ if (NewRC)
+ mri_->setRegClass(DstReg, NewRC);
}
if (NewHeuristic) {
if (!vni->def || vni->def == ~1U || vni->def == ~0U)
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)) {
+ tii_->isMoveInstr(*CopyMI, NewSrcReg, NewDstReg,
+ NewSrcSubIdx, NewDstSubIdx)) {
unsigned LoopDepth = loopInfo->getLoopDepth(CopyMBB);
JoinQueue->push(CopyRec(CopyMI, LoopDepth,
isBackEdgeCopy(CopyMI, DstReg)));
// 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 (DefMI && 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;
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) {
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);
}
/// Return true if the two specified registers belong to different register
-/// classes. The registers may be either phys or virt regs. In the
-/// case where both registers are virtual registers, it would also returns
-/// true by reference the RegB register class in SubRC if it is a subset of
-/// RegA's register class.
+/// classes. The registers may be either phys or virt regs.
bool
-SimpleRegisterCoalescing::differingRegisterClasses(unsigned RegA, unsigned RegB,
- const TargetRegisterClass *&SubRC) const {
-
+SimpleRegisterCoalescing::differingRegisterClasses(unsigned RegA,
+ unsigned RegB) const {
// Get the register classes for the first reg.
if (TargetRegisterInfo::isPhysicalRegister(RegA)) {
assert(TargetRegisterInfo::isVirtualRegister(RegB) &&
const TargetRegisterClass *RegClassA = mri_->getRegClass(RegA);
if (TargetRegisterInfo::isVirtualRegister(RegB)) {
const TargetRegisterClass *RegClassB = mri_->getRegClass(RegB);
- if (RegClassA == RegClassB)
- return false;
- SubRC = (RegClassA->hasSubClass(RegClassB)) ? RegClassB : NULL;
- return true;
+ return RegClassA != RegClassB;
}
return !RegClassA->contains(RegB);
}
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);
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.isReg() && Use.isUse() && Use.getReg() &&
for (MachineBasicBlock::iterator mii = mbb->begin(), mie = mbb->end();
mii != mie; ) {
MachineInstr *MI = mii;
- unsigned SrcReg, DstReg;
+ unsigned SrcReg, DstReg, SrcSubIdx, DstSubIdx;
if (JoinedCopies.count(MI)) {
// Delete all coalesced copies.
- if (!tii_->isMoveInstr(*MI, SrcReg, DstReg)) {
+ if (!tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)) {
assert((MI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG ||
MI->getOpcode() == TargetInstrInfo::INSERT_SUBREG) &&
"Unrecognized copy instruction");
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
+ if (!Reg)
+ continue;
if (TargetRegisterInfo::isVirtualRegister(Reg))
DeadDefs.push_back(Reg);
if (MO.isDead())
}
// If the move will be an identity move delete it
- bool isMove = tii_->isMoveInstr(*MI, SrcReg, DstReg);
+ bool isMove= tii_->isMoveInstr(*MI, SrcReg, DstReg, SrcSubIdx, DstSubIdx);
if (isMove && SrcReg == DstReg) {
if (li_->hasInterval(SrcReg)) {
LiveInterval &RegInt = li_->getInterval(SrcReg);
projects / oota-llvm.git / blobdiff