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Correctly compute live variable information for physical registers

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when an implicitely defined register is later used by an alias. For example:

         call foo
         %reg1024 = mov %AL

The call implicitely defines EAX but only AL is used. Before this fix
no information was available on AL. Now EAX and all its aliases except
AL get defined and die at the call instruction whereas AL lives to be
killed by the assignment.

llvm-svn: 10813
This commit is contained in:
Alkis Evlogimenos 2004-01-13 06:24:30 +00:00
parent 807e401607
commit 1a7b3c80d7
3 changed files with 30 additions and 33 deletions
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17
lib/CodeGen/LiveIntervals.cpp
View File

@ -261,6 +261,8 @@ void LiveIntervals::handleRegisterDef(MachineBasicBlock* mbb,
if (reg < MRegisterInfo::FirstVirtualRegister) {
if (allocatableRegisters_[reg]) {
handlePhysicalRegisterDef(mbb, mi, reg);
for (const unsigned* as = mri_->getAliasSet(reg); *as; ++as)
handlePhysicalRegisterDef(mbb, mi, *as);
}
}
else {
@ -300,10 +302,8 @@ void LiveIntervals::computeIntervals()
instr->print(std::cerr, *tm_););
// handle implicit defs
for (const unsigned* id = tid.ImplicitDefs; *id; ++id) {
unsigned physReg = *id;
handlePhysicalRegisterDef(mbb, mi, physReg);
}
for (const unsigned* id = tid.ImplicitDefs; *id; ++id)
handleRegisterDef(mbb, mi, *id);
// handle explicit defs
for (int i = instr->getNumOperands() - 1; i >= 0; --i) {
@ -312,14 +312,9 @@ void LiveIntervals::computeIntervals()
if (!mop.isRegister())
continue;
unsigned reg = mop.getAllocatedRegNum();
// handle defs - build intervals
if (mop.isDef()) {
if (reg < MRegisterInfo::FirstVirtualRegister)
handlePhysicalRegisterDef(mbb, mi, reg);
else
handleVirtualRegisterDef(mbb, mi, reg);
}
if (mop.isDef())
handleRegisterDef(mbb, mi, mop.getAllocatedRegNum());
}
}
}

31
lib/CodeGen/LiveVariables.cpp
View File

@ -117,14 +117,6 @@ void LiveVariables::HandlePhysRegUse(unsigned Reg, MachineInstr *MI) {
if (PhysRegInfo[Reg]) {
PhysRegInfo[Reg] = MI;
PhysRegUsed[Reg] = true;
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) {
if (MachineInstr *LastUse = PhysRegInfo[*AliasSet]) {
PhysRegInfo[*AliasSet] = MI;
PhysRegUsed[*AliasSet] = true;
}
}
}
}
@ -135,20 +127,21 @@ void LiveVariables::HandlePhysRegDef(unsigned Reg, MachineInstr *MI) {
RegistersKilled.insert(std::make_pair(LastUse, Reg));
else
RegistersDead.insert(std::make_pair(LastUse, Reg));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) {
if (MachineInstr *LastUse = PhysRegInfo[*AliasSet]) {
if (PhysRegUsed[*AliasSet])
RegistersKilled.insert(std::make_pair(LastUse, *AliasSet));
else
RegistersDead.insert(std::make_pair(LastUse, *AliasSet));
PhysRegInfo[*AliasSet] = 0; // Kill the aliased register
}
}
}
PhysRegInfo[Reg] = MI;
PhysRegUsed[Reg] = false;
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) {
if (MachineInstr *LastUse = PhysRegInfo[*AliasSet]) {
if (PhysRegUsed[*AliasSet])
RegistersKilled.insert(std::make_pair(LastUse, *AliasSet));
else
RegistersDead.insert(std::make_pair(LastUse, *AliasSet));
}
PhysRegInfo[*AliasSet] = MI;
PhysRegUsed[*AliasSet] = false;
}
}
bool LiveVariables::runOnMachineFunction(MachineFunction &MF) {

15
lib/CodeGen/RegAllocLocal.cpp
View File

@ -232,9 +232,8 @@ void RA::removePhysReg(unsigned PhysReg) {
std::vector<unsigned>::iterator It =
std::find(PhysRegsUseOrder.begin(), PhysRegsUseOrder.end(), PhysReg);
assert(It != PhysRegsUseOrder.end() &&
"Spilled a physical register, but it was not in use list!");
PhysRegsUseOrder.erase(It);
if (It != PhysRegsUseOrder.end())
PhysRegsUseOrder.erase(It);
}
@ -550,6 +549,11 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
spillPhysReg(MBB, I, Reg, true); // Spill any existing value in the reg
PhysRegsUsed[Reg] = 0; // It is free and reserved now
PhysRegsUseOrder.push_back(Reg);
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) {
PhysRegsUseOrder.push_back(*AliasSet);
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
}
}
// Loop over the implicit defs, spilling them as well.
@ -559,6 +563,11 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
spillPhysReg(MBB, I, Reg);
PhysRegsUseOrder.push_back(Reg);
PhysRegsUsed[Reg] = 0; // It is free and reserved now
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) {
PhysRegsUseOrder.push_back(*AliasSet);
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
}
}
// Okay, we have allocated all of the source operands and spilled any values