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Do not form ldrd / strd if the two dests / srcs are the same. Code clean up.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73413 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-06-15 20:54:56 +00:00
parent 636768458f
commit d780f35794
1 changed files with 73 additions and 59 deletions
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132
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
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@ -937,7 +937,11 @@ namespace {
}
private:
bool SatisfyLdStDWordlignment(MachineInstr *MI);
bool CanFormLdStDWord(MachineInstr *Op0, MachineInstr *Op1, DebugLoc &dl,
unsigned &NewOpc, unsigned &EvenReg,
unsigned &OddReg, unsigned &BaseReg,
unsigned &OffReg, unsigned &Offset,
unsigned &PredReg, ARMCC::CondCodes &Pred);
bool RescheduleOps(MachineBasicBlock *MBB,
SmallVector<MachineInstr*, 4> &Ops,
unsigned Base, bool isLd,
@ -995,16 +999,55 @@ static bool IsSafeToMove(bool isLd, unsigned Base,
return true;
}
bool ARMPreAllocLoadStoreOpt::SatisfyLdStDWordlignment(MachineInstr *MI) {
if (!MI->hasOneMemOperand() ||
!MI->memoperands_begin()->getValue() ||
MI->memoperands_begin()->isVolatile())
bool
ARMPreAllocLoadStoreOpt::CanFormLdStDWord(MachineInstr *Op0, MachineInstr *Op1,
DebugLoc &dl,
unsigned &NewOpc, unsigned &EvenReg,
unsigned &OddReg, unsigned &BaseReg,
unsigned &OffReg, unsigned &Offset,
unsigned &PredReg,
ARMCC::CondCodes &Pred) {
// FIXME: FLDS / FSTS -> FLDD / FSTD
unsigned Opcode = Op0->getOpcode();
if (Opcode == ARM::LDR)
NewOpc = ARM::LDRD;
else if (Opcode == ARM::STR)
NewOpc = ARM::STRD;
else
return 0;
// Must sure the base address satisfies i64 ld / st alignment requirement.
if (!Op0->hasOneMemOperand() ||
!Op0->memoperands_begin()->getValue() ||
Op0->memoperands_begin()->isVolatile())
return false;
unsigned Align = MI->memoperands_begin()->getAlignment();
unsigned Align = Op0->memoperands_begin()->getAlignment();
unsigned ReqAlign = STI->hasV6Ops()
? TD->getPrefTypeAlignment(Type::Int64Ty) : 8; // Pre-v6 need 8-byte align
return Align >= ReqAlign;
if (Align < ReqAlign)
return false;
// Then make sure the immediate offset fits.
int OffImm = getMemoryOpOffset(Op0);
ARM_AM::AddrOpc AddSub = ARM_AM::add;
if (OffImm < 0) {
AddSub = ARM_AM::sub;
OffImm = - OffImm;
}
if (OffImm >= 256) // 8 bits
return false;
Offset = ARM_AM::getAM3Opc(AddSub, OffImm);
EvenReg = Op0->getOperand(0).getReg();
OddReg = Op0->getOperand(1).getReg();
if (EvenReg == OddReg)
return false;
BaseReg = Op0->getOperand(1).getReg();
OffReg = Op0->getOperand(2).getReg();
Pred = getInstrPredicate(Op0, PredReg);
dl = Op0->getDebugLoc();
return true;
}
bool ARMPreAllocLoadStoreOpt::RescheduleOps(MachineBasicBlock *MBB,
@ -1075,66 +1118,31 @@ bool ARMPreAllocLoadStoreOpt::RescheduleOps(MachineBasicBlock *MBB,
// If we are moving a pair of loads / stores, see if it makes sense
// to try to allocate a pair of registers that can form register pairs.
unsigned PairOpcode = 0;
MachineInstr *Op0 = Ops.back();
MachineInstr *Op1 = Ops[Ops.size()-2];
unsigned EvenReg = 0, OddReg = 0;
unsigned BaseReg = 0, OffReg = 0, PredReg = 0;
ARMCC::CondCodes Pred = ARMCC::AL;
unsigned NewOpc = 0;
unsigned Offset = 0;
DebugLoc dl;
if (NumMove == 2 && CanFormLdStDWord(Op0, Op1, dl, NewOpc,
EvenReg, OddReg, BaseReg, OffReg,
Offset, PredReg, Pred)) {
Ops.pop_back();
Ops.pop_back();
MBB->erase(Op0);
MBB->erase(Op1);
// Make sure the alignment requirement is met.
if (NumMove == 2 && SatisfyLdStDWordlignment(Ops.back())) {
int Opcode = Ops.back()->getOpcode();
// FIXME: FLDS / FSTS -> FLDD / FSTD
if (Opcode == ARM::LDR)
PairOpcode = ARM::LDRD;
else if (Opcode == ARM::STR)
PairOpcode = ARM::STRD;
}
// Then make sure the immediate offset fits.
if (PairOpcode) {
int OffImm = getMemoryOpOffset(Ops.back());
ARM_AM::AddrOpc AddSub = ARM_AM::add;
if (OffImm < 0) {
AddSub = ARM_AM::sub;
OffImm = - OffImm;
}
if (OffImm >= 256) // 8 bits
PairOpcode = 0;
else
Offset = ARM_AM::getAM3Opc(AddSub, OffImm);
}
if (!PairOpcode) {
for (unsigned i = 0; i != NumMove; ++i) {
MachineInstr *Op = Ops.back();
Ops.pop_back();
MBB->splice(InsertPos, MBB, Op);
}
} else {
// Form the pair instruction instead.
unsigned EvenReg = 0, OddReg = 0;
unsigned BaseReg = 0, OffReg = 0, PredReg = 0;
ARMCC::CondCodes Pred = ARMCC::AL;
DebugLoc dl;
for (unsigned i = 0; i != NumMove; ++i) {
MachineInstr *Op = Ops.back();
Ops.pop_back();
unsigned Reg = Op->getOperand(0).getReg();
if (i == 0) {
EvenReg = Reg;
BaseReg = Op->getOperand(1).getReg();
OffReg = Op->getOperand(2).getReg();
Pred = getInstrPredicate(Op, PredReg);
dl = Op->getDebugLoc();
} else
OddReg = Reg;
MBB->erase(Op);
}
// Form the pair instruction.
if (isLd)
BuildMI(*MBB, InsertPos, dl, TII->get(PairOpcode))
BuildMI(*MBB, InsertPos, dl, TII->get(NewOpc))
.addReg(EvenReg, RegState::Define)
.addReg(OddReg, RegState::Define)
.addReg(BaseReg).addReg(0).addImm(Offset)
.addImm(Pred).addReg(PredReg);
else
BuildMI(*MBB, InsertPos, dl, TII->get(PairOpcode))
BuildMI(*MBB, InsertPos, dl, TII->get(NewOpc))
.addReg(EvenReg)
.addReg(OddReg)
.addReg(BaseReg).addReg(0).addImm(Offset)
@ -1143,6 +1151,12 @@ bool ARMPreAllocLoadStoreOpt::RescheduleOps(MachineBasicBlock *MBB,
// Add register allocation hints to form register pairs.
MRI->setRegAllocationHint(EvenReg, ARMRI::RegPairEven, OddReg);
MRI->setRegAllocationHint(OddReg, ARMRI::RegPairOdd, EvenReg);
} else {
for (unsigned i = 0; i != NumMove; ++i) {
MachineInstr *Op = Ops.back();
Ops.pop_back();
MBB->splice(InsertPos, MBB, Op);
}
}
NumLdStMoved += NumMove;