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ok, this much doesn't seem to bork anything 

llvm-svn: 37749
This commit is contained in:
Duraid Madina 2007-06-27 08:31:07 +00:00
parent a415dcaa2a
commit 89183dcc14
1 changed files with 48 additions and 25 deletions
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73
llvm/lib/CodeGen/RegAllocBigBlock.cpp
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@ -357,18 +357,7 @@ void RABigBlock::spillPhysReg(MachineBasicBlock &MBB, MachineInstr *I,
*AliasSet; ++AliasSet)
if (PhysRegsUsed[*AliasSet] != -1 && // Spill aliased register.
PhysRegsUsed[*AliasSet] != -2) // If allocatable.
if (PhysRegsUsed[*AliasSet] == 0) {
// This must have been a dead def due to something like this:
// %EAX :=
// := op %AL
// No more use of %EAX, %AH, etc.
// %EAX isn't dead upon definition, but %AH is. However %AH isn't
// an operand of definition MI so it's not marked as such.
DOUT << " Register " << RegInfo->getName(*AliasSet)
<< " [%reg" << *AliasSet
<< "] is never used, removing it frame live list\n";
removePhysReg(*AliasSet);
} else
if (PhysRegsUsed[*AliasSet])
spillVirtReg(MBB, I, PhysRegsUsed[*AliasSet], *AliasSet);
}
}
@ -582,6 +571,30 @@ void RABigBlock::FillVRegReadTable(MachineBasicBlock &MBB) {
}
}
/// isReadModWriteImplicitKill - True if this is an implicit kill for a
/// read/mod/write register, i.e. update partial register.
static bool isReadModWriteImplicitKill(MachineInstr *MI, unsigned Reg) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand& MO = MI->getOperand(i);
if (MO.isRegister() && MO.getReg() == Reg && MO.isImplicit() &&
MO.isDef() && !MO.isDead())
return true;
}
return false;
}
/// isReadModWriteImplicitDef - True if this is an implicit def for a
/// read/mod/write register, i.e. update partial register.
static bool isReadModWriteImplicitDef(MachineInstr *MI, unsigned Reg) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand& MO = MI->getOperand(i);
if (MO.isRegister() && MO.getReg() == Reg && MO.isImplicit() &&
!MO.isDef() && MO.isKill())
return true;
}
return false;
}
void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
// loop over each instruction
@ -599,7 +612,7 @@ void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
unsigned Reg = I->first;
MF->setPhysRegUsed(Reg);
PhysRegsUsed[Reg] = 0; // It is free and reserved now
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
for (const unsigned *AliasSet = RegInfo->getSubRegisters(Reg);
*AliasSet; ++AliasSet) {
if (PhysRegsUsed[*AliasSet] != -2) {
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
@ -626,8 +639,15 @@ void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
SmallVector<unsigned, 8> Kills;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand& MO = MI->getOperand(i);
if (MO.isRegister() && MO.isKill())
Kills.push_back(MO.getReg());
if (MO.isRegister() && MO.isKill()) {
if (!MO.isImplicit())
Kills.push_back(MO.getReg());
else if (!isReadModWriteImplicitKill(MI, MO.getReg()))
// These are extra physical register kills when a sub-register
// is defined (def of a sub-register is a read/mod/write of the
// larger registers). Ignore.
Kills.push_back(MO.getReg());
}
}
// Get the used operands into registers. This has the potential to spill
@ -660,13 +680,16 @@ void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
} else if (PhysRegsUsed[PhysReg] == -2) {
// Unallocatable register dead, ignore.
continue;
} else {
assert(!PhysRegsUsed[PhysReg] || PhysRegsUsed[PhysReg] == -1 &&
"Silently clearing a virtual register?");
}
if (PhysReg) {
DOUT << " Last use of " << RegInfo->getName(PhysReg)
<< "[%reg" << VirtReg <<"], removing it from live set\n";
removePhysReg(PhysReg);
for (const unsigned *AliasSet = RegInfo->getAliasSet(PhysReg);
for (const unsigned *AliasSet = RegInfo->getSubRegisters(PhysReg);
*AliasSet; ++AliasSet) {
if (PhysRegsUsed[*AliasSet] != -2) {
DOUT << " Last use of "
@ -686,11 +709,15 @@ void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
MRegisterInfo::isPhysicalRegister(MO.getReg())) {
unsigned Reg = MO.getReg();
if (PhysRegsUsed[Reg] == -2) continue; // Something like ESP.
// These are extra physical register defs when a sub-register
// is defined (def of a sub-register is a read/mod/write of the
// larger registers). Ignore.
if (isReadModWriteImplicitDef(MI, MO.getReg())) continue;
MF->setPhysRegUsed(Reg);
spillPhysReg(MBB, MI, Reg, true); // Spill any existing value in reg
PhysRegsUsed[Reg] = 0; // It is free and reserved now
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
for (const unsigned *AliasSet = RegInfo->getSubRegisters(Reg);
*AliasSet; ++AliasSet) {
if (PhysRegsUsed[*AliasSet] != -2) {
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
@ -705,19 +732,15 @@ void RABigBlock::AllocateBasicBlock(MachineBasicBlock &MBB) {
for (const unsigned *ImplicitDefs = TID.ImplicitDefs;
*ImplicitDefs; ++ImplicitDefs) {
unsigned Reg = *ImplicitDefs;
bool IsNonAllocatable = PhysRegsUsed[Reg] == -2;
if (!IsNonAllocatable) {
if (PhysRegsUsed[Reg] != -2) {
spillPhysReg(MBB, MI, Reg, true);
PhysRegsUsed[Reg] = 0; // It is free and reserved now
}
MF->setPhysRegUsed(Reg);
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
for (const unsigned *AliasSet = RegInfo->getSubRegisters(Reg);
*AliasSet; ++AliasSet) {
if (PhysRegsUsed[*AliasSet] != -2) {
if (!IsNonAllocatable) {
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
}
PhysRegsUsed[*AliasSet] = 0; // It is free and reserved now
MF->setPhysRegUsed(*AliasSet);
}
}