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Be careful when to add implicit kill / dead operands. Don't add them during / post reg-allocation.

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llvm-svn: 36458
This commit is contained in:
Evan Cheng
2007-04-26 01:40:09 +00:00
parent d3d914b9f8
commit 43a17fe826
2 changed files with 39 additions and 23 deletions
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26
llvm/lib/CodeGen/LiveVariables.cpp
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@@ -170,7 +170,8 @@ void LiveVariables::HandleVirtRegUse(VarInfo &VRInfo, MachineBasicBlock *MBB,
MarkVirtRegAliveInBlock(VRInfo, *PI);
}
void LiveVariables::addRegisterKilled(unsigned IncomingReg, MachineInstr *MI) {
bool LiveVariables::addRegisterKilled(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound) {
bool Found = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
@@ -187,17 +188,21 @@ void LiveVariables::addRegisterKilled(unsigned IncomingReg, MachineInstr *MI) {
RegInfo->isSuperRegister(IncomingReg, Reg) &&
MO.isKill())
// A super-register kill already exists.
return;
return true;
}
}
// If not found, this means an alias of one of the operand is killed. Add a
// new implicit operand.
if (!Found)
// new implicit operand if required.
if (!Found && AddIfNotFound) {
MI->addRegOperand(IncomingReg, false/*IsDef*/,true/*IsImp*/,true/*IsKill*/);
return true;
}
return Found;
}
void LiveVariables::addRegisterDead(unsigned IncomingReg, MachineInstr *MI) {
bool LiveVariables::addRegisterDead(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound) {
bool Found = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
@@ -214,15 +219,18 @@ void LiveVariables::addRegisterDead(unsigned IncomingReg, MachineInstr *MI) {
RegInfo->isSuperRegister(IncomingReg, Reg) &&
MO.isDead())
// There exists a super-register that's marked dead.
return;
return true;
}
}
// If not found, this means an alias of one of the operand is dead. Add a
// new implicit operand.
if (!Found)
if (!Found && AddIfNotFound) {
MI->addRegOperand(IncomingReg, true/*IsDef*/,true/*IsImp*/,false/*IsKill*/,
true/*IsDead*/);
return true;
}
return Found;
}
void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
@@ -271,9 +279,9 @@ void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
addRegisterKilled(Reg, LastRef);
else if (PhysRegPartUse[Reg])
// Add implicit use / kill to last use of a sub-register.
addRegisterKilled(Reg, PhysRegPartUse[Reg]);
addRegisterKilled(Reg, PhysRegPartUse[Reg], true);
else
addRegisterDead(Reg, LastRef);
addRegisterDead(Reg, LastRef, true);
}
PhysRegInfo[Reg] = MI;
PhysRegUsed[Reg] = false;