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Substantial fixes to live range handling, fixing several problems, getting

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strtol to not miscompile, and fixing bug: 2002-12-23-LocalRAProblem.llx


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5132 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2002-12-24 00:04:55 +00:00
parent 5bcd95c57f
commit 0eb172cc4a
1 changed files with 35 additions and 27 deletions
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62
lib/CodeGen/RegAllocLocal.cpp
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@ -61,16 +61,17 @@ namespace {
void MarkPhysRegRecentlyUsed(unsigned Reg) {
assert(!PhysRegsUseOrder.empty() && "No registers used!");
if (PhysRegsUseOrder.back() != Reg) {
for (unsigned i = PhysRegsUseOrder.size(); i != 0; --i)
if (areRegsEqual(Reg, PhysRegsUseOrder[i-1])) { // remove from middle
unsigned RegMatch = PhysRegsUseOrder[i-1];
PhysRegsUseOrder.erase(PhysRegsUseOrder.begin()+i-1);
PhysRegsUseOrder.push_back(RegMatch); // Add it to the end of the list
if (RegMatch == Reg)
return; // Found an exact match, exit early
}
}
if (PhysRegsUseOrder.back() == Reg) return; // Already most recently used
for (unsigned i = PhysRegsUseOrder.size(); i != 0; --i)
if (areRegsEqual(Reg, PhysRegsUseOrder[i-1])) {
unsigned RegMatch = PhysRegsUseOrder[i-1]; // remove from middle
PhysRegsUseOrder.erase(PhysRegsUseOrder.begin()+i-1);
// Add it to the end of the list
PhysRegsUseOrder.push_back(RegMatch);
if (RegMatch == Reg)
return; // Found an exact match, exit early
}
}
public:
@ -160,11 +161,11 @@ namespace {
void spillPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
unsigned PhysReg) {
std::map<unsigned, unsigned>::iterator PI = PhysRegsUsed.find(PhysReg);
if (PI != PhysRegsUsed.end()) { // Only spill it if it's used!
if (PI != PhysRegsUsed.end()) { // Only spill it if it's used!
spillVirtReg(MBB, I, PI->second, PhysReg);
} else if (const unsigned *AliasSet = RegInfo.getAliasSet(PhysReg)) {
// If the selected register aliases any other registers, we must make sure
// that one of the aliases isn't alive...
// If the selected register aliases any other registers, we must make
// sure that one of the aliases isn't alive...
for (unsigned i = 0; AliasSet[i]; ++i) {
PI = PhysRegsUsed.find(AliasSet[i]);
if (PI != PhysRegsUsed.end()) // Spill aliased register...
@ -503,12 +504,15 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
// Loop over all of the operands of the instruction, spilling registers that
// are defined, and marking explicit destinations in the PhysRegsUsed map.
// FIXME: We don't need to spill a register if this is the last use of the
// value!
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).opIsDef() &&
MI->getOperand(i).isPhysicalRegister()) {
unsigned Reg = MI->getOperand(i).getAllocatedRegNum();
spillPhysReg(MBB, I, Reg);
PhysRegsUsed[Reg] = 0; // It's free now, and it's reserved
PhysRegsUsed[Reg] = 0; // It is free and reserved now
PhysRegsUseOrder.push_back(Reg);
}
@ -520,11 +524,14 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
// We don't want to spill implicit definitions if they were explicitly
// chosen. For this reason, check to see now if the register we are
// to spill has a vreg of 0.
if (PhysRegsUsed.count(Reg) && PhysRegsUsed[Reg] != 0) {
if (PhysRegsUsed.count(Reg) && PhysRegsUsed[Reg] != 0)
spillPhysReg(MBB, I, Reg);
PhysRegsUsed[Reg] = 0; // It's free now, and it's reserved
PhysRegsUseOrder.push_back(Reg);
}
else if (PhysRegsUsed.count(Reg)) {
// Remove the entry from PhysRegsUseOrder to avoid having two entries!
removePhysReg(Reg);
}
PhysRegsUseOrder.push_back(Reg);
PhysRegsUsed[Reg] = 0; // It is free and reserved now
}
// Loop over the implicit uses, making sure that they are at the head of the
@ -534,8 +541,8 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
MarkPhysRegRecentlyUsed(ImplicitUses[i]);
// Loop over all of the operands again, getting the used operands into
// registers. This has the potiential to spill incoming values because we
// are out of registers.
// registers. This has the potiential to spill incoming values if we are
// out of registers.
//
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).opIsUse() &&
@ -576,16 +583,17 @@ void RA::AllocateBasicBlock(MachineBasicBlock &MBB) {
}
if (!DisableKill) {
// If this instruction is the last user of anything in registers, kill the
// value, freeing the register being used, so it doesn't need to be spilled
// to memory at the end of the block.
// If this instruction is the last user of anything in registers, kill the
// value, freeing the register being used, so it doesn't need to be
// spilled to memory at the end of the block.
std::multimap<MachineInstr*, unsigned>::iterator LUOI =
LastUserOf.lower_bound(MI);
for (; LUOI != LastUserOf.end() && LUOI->first == MI; ++MI) {// entry found?
unsigned VirtReg = LUOI->second;
for (; LUOI != LastUserOf.end() && LUOI->first == MI; ++MI) {
unsigned VirtReg = LUOI->second; // entry found?
unsigned PhysReg = Virt2PhysRegMap[VirtReg];
if (PhysReg) {
DEBUG(std::cout << "V: " << VirtReg << " P: " << PhysReg << " Last use of: " << *MI);
DEBUG(std::cout << "V: " << VirtReg << " P: " << PhysReg
<< " Last use of: " << *MI);
removePhysReg(PhysReg);
}
Virt2PhysRegMap.erase(VirtReg);
@ -646,7 +654,7 @@ void RA::EmitPrologue() {
///
void RA::EmitEpilogue(MachineBasicBlock &MBB) {
// Insert instructions before the return.
MachineBasicBlock::iterator I = --MBB.end();
MachineBasicBlock::iterator I = MBB.end()-1;
const unsigned *CSRegs = RegInfo.getCalleeSaveRegs();
for (unsigned i = 0; CSRegs[i]; ++i) {