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Make load / store optimizer use register scavenger.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34986 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-03-06 21:59:20 +00:00
parent caddd590f7
commit a90f3408b3
1 changed files with 58 additions and 21 deletions
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79
lib/Target/ARM/ARMLoadStoreOptimizer.cpp
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@ -59,6 +59,8 @@ namespace {
typedef SmallVector<MemOpQueueEntry,8> MemOpQueue;
typedef MemOpQueue::iterator MemOpQueueIter;
void AdvanceRS(MachineBasicBlock *MBB, MemOpQueue &MemOps);
SmallVector<MachineBasicBlock::iterator, 4>
MergeLDR_STR(MachineBasicBlock &MBB, unsigned SIndex, unsigned Base,
int Opcode, unsigned Size, MemOpQueue &MemOps);
@ -103,8 +105,9 @@ static int getLoadStoreMultipleOpcode(int Opcode) {
/// registers in Regs as the register operands that would be loaded / stored.
/// It returns true if the transformation is done.
static bool mergeOps(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
int Offset, unsigned Base, int Opcode,
SmallVector<unsigned, 8> &Regs,
int Offset, unsigned Base, bool BaseKill, int Opcode,
SmallVector<std::pair<unsigned, bool>, 8> &Regs,
RegScavenger *RS,
const TargetInstrInfo *TII) {
// Only a single register to load / store. Don't bother.
unsigned NumRegs = Regs.size();
@ -130,10 +133,12 @@ static bool mergeOps(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
if (Opcode == ARM::LDR)
// If it is a load, then just use one of the destination register to
// use as the new base.
NewBase = Regs[NumRegs-1];
NewBase = Regs[NumRegs-1].first;
else {
// FIXME: Try scavenging a register to use as a new base.
NewBase = ARM::R12;
// Try to find a free register to use as a new base.
NewBase = RS ? RS->FindUnusedReg(&ARM::GPRRegClass) : (unsigned)ARM::R12;
if (NewBase == 0)
return false;
}
int BaseOpc = ARM::ADDri;
if (Offset < 0) {
@ -143,52 +148,78 @@ static bool mergeOps(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
int ImmedOffset = ARM_AM::getSOImmVal(Offset);
if (ImmedOffset == -1)
return false; // Probably not worth it then.
BuildMI(MBB, MBBI, TII->get(BaseOpc), NewBase).addReg(Base).addImm(ImmedOffset);
BuildMI(MBB, MBBI, TII->get(BaseOpc), NewBase)
.addReg(Base, false, false, BaseKill).addImm(ImmedOffset);
Base = NewBase;
BaseKill = true; // New base is always killed right its use.
}
bool isDPR = Opcode == ARM::FLDD || Opcode == ARM::FSTD;
bool isDef = Opcode == ARM::LDR || Opcode == ARM::FLDS || Opcode == ARM::FLDD;
Opcode = getLoadStoreMultipleOpcode(Opcode);
MachineInstrBuilder MIB = (isAM4)
? BuildMI(MBB, MBBI, TII->get(Opcode)).addReg(Base)
? BuildMI(MBB, MBBI, TII->get(Opcode)).addReg(Base, false, false, BaseKill)
.addImm(ARM_AM::getAM4ModeImm(Mode))
: BuildMI(MBB, MBBI, TII->get(Opcode)).addReg(Base)
: BuildMI(MBB, MBBI, TII->get(Opcode)).addReg(Base, false, false, BaseKill)
.addImm(ARM_AM::getAM5Opc(Mode, false, isDPR ? NumRegs<<1 : NumRegs));
for (unsigned i = 0; i != NumRegs; ++i)
MIB = MIB.addReg(Regs[i], Opcode == isDef);
MIB = MIB.addReg(Regs[i].first, isDef, false, Regs[i].second);
return true;
}
/// AdvanceRS - Advance register scavenger to just before the earliest memory
/// op that is being merged.
void ARMLoadStoreOpt::AdvanceRS(MachineBasicBlock *MBB, MemOpQueue &MemOps) {
MachineBasicBlock::iterator Loc = MemOps[0].MBBI;
unsigned Position = MemOps[0].Position;
for (unsigned i = 1, e = MemOps.size(); i != e; ++i) {
if (MemOps[i].Position < Position) {
Position = MemOps[i].Position;
Loc = MemOps[i].MBBI;
}
}
if (Loc != MBB->begin())
RS->forward(prior(Loc));
}
/// MergeLDR_STR - Merge a number of load / store instructions into one or more
/// load / store multiple instructions.
SmallVector<MachineBasicBlock::iterator, 4>
ARMLoadStoreOpt::MergeLDR_STR(MachineBasicBlock &MBB,
unsigned SIndex, unsigned Base, int Opcode,
unsigned Size, MemOpQueue &MemOps) {
bool isAM4 = Opcode == ARM::LDR || Opcode == ARM::STR;
if (RS && SIndex == 0)
AdvanceRS(&MBB, MemOps);
SmallVector<MachineBasicBlock::iterator, 4> Merges;
SmallVector<std::pair<unsigned,bool>, 8> Regs;
bool isAM4 = Opcode == ARM::LDR || Opcode == ARM::STR;
int Offset = MemOps[SIndex].Offset;
int SOffset = Offset;
unsigned Pos = MemOps[SIndex].Position;
MachineBasicBlock::iterator Loc = MemOps[SIndex].MBBI;
SmallVector<unsigned, 8> Regs;
unsigned PReg = MemOps[SIndex].MBBI->getOperand(0).getReg();
unsigned PRegNum = ARMRegisterInfo::getRegisterNumbering(PReg);
Regs.push_back(PReg);
bool isKill = MemOps[SIndex].MBBI->getOperand(0).isKill();
Regs.push_back(std::make_pair(PReg, isKill));
for (unsigned i = SIndex+1, e = MemOps.size(); i != e; ++i) {
int NewOffset = MemOps[i].Offset;
unsigned Reg = MemOps[i].MBBI->getOperand(0).getReg();
unsigned RegNum = ARMRegisterInfo::getRegisterNumbering(Reg);
isKill = MemOps[i].MBBI->getOperand(0).isKill();
// AM4 - register numbers in ascending order.
// AM5 - consecutive register numbers in ascending order.
if (NewOffset == Offset + (int)Size &&
((isAM4 && RegNum > PRegNum) || RegNum == PRegNum+1)) {
Offset += Size;
Regs.push_back(Reg);
Regs.push_back(std::make_pair(Reg, isKill));
PRegNum = RegNum;
} else {
// Can't merge this in. Try merge the earlier ones first.
if (mergeOps(MBB, ++Loc, SOffset, Base, Opcode, Regs, TII)) {
if (mergeOps(MBB, ++Loc, SOffset, Base, false, Opcode, Regs, RS, TII)) {
Merges.push_back(prior(Loc));
for (unsigned j = SIndex; j < i; ++j) {
MBB.erase(MemOps[j].MBBI);
@ -207,7 +238,8 @@ ARMLoadStoreOpt::MergeLDR_STR(MachineBasicBlock &MBB,
}
}
if (mergeOps(MBB, ++Loc, SOffset, Base, Opcode, Regs, TII)) {
bool BaseKill = Loc->findRegisterUseOperand(Base, true) != NULL;
if (mergeOps(MBB, ++Loc, SOffset, Base, BaseKill, Opcode, Regs, RS, TII)) {
Merges.push_back(prior(Loc));
for (unsigned i = SIndex, e = MemOps.size(); i != e; ++i) {
MBB.erase(MemOps[i].MBBI);
@ -381,6 +413,7 @@ static bool mergeBaseUpdateLoadStore(MachineBasicBlock &MBB,
const TargetInstrInfo *TII) {
MachineInstr *MI = MBBI;
unsigned Base = MI->getOperand(1).getReg();
bool BaseKill = MI->getOperand(1).isKill();
unsigned Bytes = getLSMultipleTransferSize(MI);
int Opcode = MI->getOpcode();
bool isAM2 = Opcode == ARM::LDR || Opcode == ARM::STR;
@ -434,18 +467,23 @@ static bool mergeBaseUpdateLoadStore(MachineBasicBlock &MBB,
true, isDPR ? 2 : 1);
if (isLd) {
if (isAM2)
// LDR_PRE, LDR_POST;
BuildMI(MBB, MBBI, TII->get(NewOpc), MI->getOperand(0).getReg())
.addReg(Base, true).addReg(Base).addReg(0).addImm(Offset);
.addReg(Base, true)
.addReg(Base).addReg(0).addImm(Offset);
else
BuildMI(MBB, MBBI, TII->get(NewOpc)).addReg(Base)
BuildMI(MBB, MBBI, TII->get(NewOpc)).addReg(Base, false, false, BaseKill)
.addImm(Offset).addReg(MI->getOperand(0).getReg(), true);
} else {
MachineOperand &MO = MI->getOperand(0);
if (isAM2)
BuildMI(MBB, MBBI, TII->get(NewOpc), Base).addReg(MI->getOperand(0).getReg())
// STR_PRE, STR_POST;
BuildMI(MBB, MBBI, TII->get(NewOpc), Base)
.addReg(MO.getReg(), false, false, MO.isKill())
.addReg(Base).addReg(0).addImm(Offset);
else
BuildMI(MBB, MBBI, TII->get(NewOpc)).addReg(Base)
.addImm(Offset).addReg(MI->getOperand(0).getReg(), false);
.addImm(Offset).addReg(MO.getReg(), false, false, MO.isKill());
}
MBB.erase(MBBI);
@ -494,7 +532,6 @@ bool ARMLoadStoreOpt::LoadStoreMultipleOpti(MachineBasicBlock &MBB) {
int Opcode = MBBI->getOpcode();
bool isAM2 = Opcode == ARM::LDR || Opcode == ARM::STR;
unsigned Size = getLSMultipleTransferSize(MBBI);
unsigned Base = MBBI->getOperand(1).getReg();
unsigned OffIdx = MBBI->getNumOperands()-1;
unsigned OffField = MBBI->getOperand(OffIdx).getImm();
@ -564,7 +601,7 @@ bool ARMLoadStoreOpt::LoadStoreMultipleOpti(MachineBasicBlock &MBB) {
if (TryMerge) {
if (NumMemOps > 1) {
SmallVector<MachineBasicBlock::iterator,4> MBBII =
MergeLDR_STR(MBB, 0, CurrBase, CurrOpc, CurrSize,MemOps);
MergeLDR_STR(MBB, 0, CurrBase, CurrOpc, CurrSize, MemOps);
// Try folding preceeding/trailing base inc/dec into the generated
// LDM/STM ops.
for (unsigned i = 0, e = MBBII.size(); i < e; ++i)