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dpu: llvm: fix merge of combo when having debug instructions
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fix #19
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Romaric JODIN committed Oct 22, 2019
1 parent 515169b commit f4c6f49
Showing 1 changed file with 55 additions and 13 deletions.
68 changes: 55 additions & 13 deletions llvm/lib/Target/DPU/DPUMergeComboInstrPass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -178,6 +178,20 @@ static const ISD::CondCode sourceConditions[] = {
ISD::SETOEQ, ISD::SETOGE, ISD::SETOLT, ISD::SETONE, ISD::SETUEQ,
ISD::SETEQ, ISD::SETGE, ISD::SETLT, ISD::SETNE};

static MachineInstr *
getLastNonDebugInstrFrom(MachineBasicBlock::reverse_iterator &I,
MachineBasicBlock::reverse_iterator REnd) {
// Skip all the debug instructions.
while (I != REnd &&
(I->isDebugValue() || I->getOpcode() == TargetOpcode::DBG_VALUE)) {
++I;
}
if (I == REnd) {
return NULL;
}
return &*I;
}

static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
const DPUInstrInfo &InstrInfo) {
MachineBasicBlock::reverse_iterator I = MBB->rbegin(), REnd = MBB->rend();
Expand All @@ -201,28 +215,24 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
std::set<ISD::CondCode> sourceConditionsSet = std::set<ISD::CondCode>(
std::begin(sourceConditions), std::end(sourceConditions));

// Skip all the debug instructions.
while (I != REnd && I->isDebugValue()) {
++I;
}

if (I == REnd) {
LastInst = getLastNonDebugInstrFrom(I, REnd);
if (LastInst == NULL) {
LLVM_DEBUG(dbgs() << "KO: I == REnd\n");
return false;
}

LastInst = &*I;

if (++I == REnd) {
I++;
SecondLastInst = getLastNonDebugInstrFrom(I, REnd);
if (SecondLastInst == NULL) {
LLVM_DEBUG(dbgs() << "KO: I++ == REnd\n");
return false;
}

SecondLastInst = &*I;

LastOpc = LastInst->getOpcode();
SecondLastOpc = SecondLastInst->getOpcode();

switch (SecondLastOpc) {
default:
LLVM_DEBUG(dbgs() << "KO: Unknown SecondLastOpc\n");
return false;
case DPU::MOVEri:
OpPrototype = OpriLimited;
Expand Down Expand Up @@ -600,6 +610,8 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
if ((OpPrototype == OprriLimited) || (OpPrototype == OprirLimited)) {
MachineOperand &immOperand = SecondLastInst->getOperand(2);
if (!immOperand.isImm()) {
LLVM_DEBUG(dbgs() << "KO: (OpPrototype == OprriLimited) || (OpPrototype "
"== OprirLimited) && !immOperand.isImm()\n");
return false;
}

Expand All @@ -609,6 +621,9 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
} else if (OpPrototype == OpriLimited) {
MachineOperand &immOperand = SecondLastInst->getOperand(1);
if (!immOperand.isImm()) {
LLVM_DEBUG(
dbgs()
<< "KO: (OpPrototype == OpriLimited) && !immOperand.isImm()\n");
return false;
}

Expand All @@ -619,9 +634,12 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,

switch (LastOpc) {
default:
LLVM_DEBUG(dbgs() << "KO: Unknown LastOpc\n");
return false;
case DPU::JUMPi: {
if (!ImmCanBeEncodedOn8Bits) {
LLVM_DEBUG(
dbgs() << "KO: LastOpc == DPU::JUMPi && !ImmCanBeEncodedOn8Bits\n");
return false;
}

Expand Down Expand Up @@ -653,6 +671,7 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
auto actualConditionOperand = MachineOperand::CreateImm(actualCondition);
ComboInst.add(actualConditionOperand).add(LastInst->getOperand(0));

LLVM_DEBUG(dbgs() << "OK\n"; LastInst->dump(); SecondLastInst->dump(););
LastInst->eraseFromParent();
SecondLastInst->eraseFromParent();

Expand All @@ -673,12 +692,18 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
case Oprr:
if ((SecondLastInst->getOperand(1).getReg() !=
LastInst->getOperand(1).getReg())) {
LLVM_DEBUG(dbgs() << "KO: LastOpc == DPU::Jcci && "
"(SecondLastInst->getOperand(1).getReg() != "
"LastInst->getOperand(1).getReg())\n");
return false;
}
isSourceCondition = true;
usableConditions = sourceConditionsSet;
break;
case OpriLimited:
LLVM_DEBUG(
dbgs()
<< "KO: LastOpc == DPU::Jcci && OpPrototype == OpriLimited\n");
return false;
}
}
Expand All @@ -692,6 +717,11 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
if (!canFindUnaryConditionForCondition(
LastInst->getOperand(0).getImm(), LastInst->getOperand(2).getImm(),
actualCondition, availableConditions)) {
LLVM_DEBUG(
dbgs() << "KO: LastOpc == DPU::Jcci && "
"(!canFindUnaryConditionForCondition(LastInst->getOperand("
"0).getImm(), LastInst->getOperand(2).getImm(), "
"actualCondition, availableConditions))\n");
return false;
}

Expand All @@ -705,14 +735,23 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,

if (LastInst->getOperand(1).isKill() && !isSourceCondition) {
if (!ImmCanBeEncodedOn11Bits) {
LLVM_DEBUG(
dbgs()
<< "KO: LastOpc == DPU::Jcci && (LastInst->getOperand(1).isKill() "
"&& !isSourceCondition) && (!ImmCanBeEncodedOn11Bits)\n");
return false;
}
// todo: this is not optimal. One register has been allocated but not used
// now. This can become an issue (unnecessary spilling)
ComboInst = BuildMI(MBB, SecondLastInst->getDebugLoc(),
InstrInfo.get(OpNullJumpOpc)).addReg(DPU::ZERO);
InstrInfo.get(OpNullJumpOpc))
.addReg(DPU::ZERO);
} else {
if (!ImmCanBeEncodedOn8Bits) {
LLVM_DEBUG(
dbgs()
<< "KO: LastOpc == DPU::Jcci && !(LastInst->getOperand(1).isKill() "
"&& !isSourceCondition) && (!ImmCanBeEncodedOn11Bits)\n");
return false;
}
ComboInst =
Expand Down Expand Up @@ -743,12 +782,14 @@ static bool mergeComboInstructionsInMBB(MachineBasicBlock *MBB,
ComboInst.add(LastInst->getOperand(0))
.add(LastInst->getOperand(LastInst->getNumOperands() - 1));

LLVM_DEBUG(dbgs() << "OK\n"; LastInst->dump(); SecondLastInst->dump(););
LastInst->eraseFromParent();
SecondLastInst->eraseFromParent();

return true;
}
case DPU::Jcc:
LLVM_DEBUG(dbgs() << "KO: LastOpc == DPU::Jcc\n");
return false;
}
}
Expand All @@ -764,6 +805,7 @@ bool DPUMergeComboInstrPass::runOnMachineFunction(MachineFunction &MF) {
for (auto &MFI : MF) {
MachineBasicBlock *MBB = &MFI;

LLVM_DEBUG(MBB->dump());
changeMade |= mergeComboInstructionsInMBB(MBB, InstrInfo);
}

Expand Down

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