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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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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36458 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-04-26 01:40:09 +00:00
parent 37a21457bf
commit 05350288a6
2 changed files with 39 additions and 23 deletions
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36
include/llvm/CodeGen/LiveVariables.h
View File

@ -147,12 +147,18 @@ private: // Intermediate data structures
SmallVector<unsigned, 4> *PHIVarInfo;
/// addRegisterKilled - We have determined MI kills a register. Look for the
/// operand that uses it and mark it as IsKill.
void addRegisterKilled(unsigned IncomingReg, MachineInstr *MI);
/// operand that uses it and mark it as IsKill. If AddIfNotFound is true,
/// add a implicit operand if it's not found. Returns true if the operand
/// exists / is added.
bool addRegisterKilled(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false);
/// addRegisterDead - We have determined MI defined a register without a use.
/// Look for the operand that defines it and mark it as IsDead.
void addRegisterDead(unsigned IncomingReg, MachineInstr *MI);
/// Look for the operand that defines it and mark it as IsDead. If
/// AddIfNotFound is true, add a implicit operand if it's not found. Returns
/// true if the operand exists / is added.
bool addRegisterDead(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false);
void HandlePhysRegUse(unsigned Reg, MachineInstr *MI);
void HandlePhysRegDef(unsigned Reg, MachineInstr *MI);
@ -189,11 +195,12 @@ public:
/// addVirtualRegisterKilled - Add information about the fact that the
/// specified register is killed after being used by the specified
/// instruction.
///
void addVirtualRegisterKilled(unsigned IncomingReg, MachineInstr *MI) {
addRegisterKilled(IncomingReg, MI);
getVarInfo(IncomingReg).Kills.push_back(MI);
/// instruction. If AddIfNotFound is true, add a implicit operand if it's
/// not found.
void addVirtualRegisterKilled(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false) {
if (addRegisterKilled(IncomingReg, MI, AddIfNotFound))
getVarInfo(IncomingReg).Kills.push_back(MI);
}
/// removeVirtualRegisterKilled - Remove the specified virtual
@ -225,11 +232,12 @@ public:
void removeVirtualRegistersKilled(MachineInstr *MI);
/// addVirtualRegisterDead - Add information about the fact that the specified
/// register is dead after being used by the specified instruction.
///
void addVirtualRegisterDead(unsigned IncomingReg, MachineInstr *MI) {
addRegisterDead(IncomingReg, MI);
getVarInfo(IncomingReg).Kills.push_back(MI);
/// register is dead after being used by the specified instruction. If
/// AddIfNotFound is true, add a implicit operand if it's not found.
void addVirtualRegisterDead(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false) {
if (addRegisterDead(IncomingReg, MI, AddIfNotFound))
getVarInfo(IncomingReg).Kills.push_back(MI);
}
/// removeVirtualRegisterDead - Remove the specified virtual

26
lib/CodeGen/LiveVariables.cpp
View File

@ -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;