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Adjust live intervals to support a livein set 

llvm-svn: 21182
This commit is contained in:
Chris Lattner 2005-04-09 16:17:50 +00:00
parent b59006c4a1
commit 0b1681bce1
1 changed files with 44 additions and 2 deletions
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46
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -91,6 +91,28 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
allocatableRegs_ = mri_->getAllocatableSet(fn);
r2rMap_.grow(mf_->getSSARegMap()->getLastVirtReg());
// If this function has any live ins, insert a dummy instruction at the
// beginning of the function that we will pretend "defines" the values. This
// is to make the interval analysis simpler by providing a number.
if (fn.livein_begin() != fn.livein_end()) {
unsigned FirstLiveIn = *fn.livein_begin();
// Find a reg class that contains this live in.
const TargetRegisterClass *RC = 0;
for (MRegisterInfo::regclass_iterator RCI = mri_->regclass_begin(),
E = mri_->regclass_end(); RCI != E; ++RCI)
if ((*RCI)->contains(FirstLiveIn)) {
RC = *RCI;
break;
}
MachineInstr *OldFirstMI = fn.begin()->begin();
mri_->copyRegToReg(*fn.begin(), fn.begin()->begin(),
FirstLiveIn, FirstLiveIn, RC);
assert(OldFirstMI != fn.begin()->begin() &&
"copyRetToReg didn't insert anything!");
}
// number MachineInstrs
unsigned miIndex = 0;
for (MachineFunction::iterator mbb = mf_->begin(), mbbEnd = mf_->end();
@ -103,6 +125,19 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
miIndex += InstrSlots::NUM;
}
// Note intervals due to live-in values.
if (fn.livein_begin() != fn.livein_end()) {
MachineBasicBlock *Entry = fn.begin();
for (MachineFunction::liveinout_iterator I = fn.livein_begin(),
E = fn.livein_end(); I != E; ++I) {
handlePhysicalRegisterDef(Entry, Entry->begin(),
getOrCreateInterval(*I), 0, 0);
for (const unsigned* AS = mri_->getAliasSet(*I); *AS; ++AS)
handlePhysicalRegisterDef(Entry, Entry->begin(),
getOrCreateInterval(*AS), 0, 0);
}
}
computeIntervals();
numIntervals += getNumIntervals();
@ -164,6 +199,11 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
}
}
// If we inserted a placeholder instruction at the entry of the block, remove
// it now.
if (fn.livein_begin() != fn.livein_end())
fn.begin()->erase(fn.begin()->begin());
DEBUG(dump());
return true;
}
@ -557,14 +597,16 @@ void LiveIntervals::computeIntervals()
DEBUG(std::cerr << "********** COMPUTING LIVE INTERVALS **********\n");
DEBUG(std::cerr << "********** Function: "
<< ((Value*)mf_->getFunction())->getName() << '\n');
bool IgnoreFirstInstr = mf_->livein_begin() != mf_->livein_end();
for (MachineFunction::iterator I = mf_->begin(), E = mf_->end();
I != E; ++I) {
MachineBasicBlock* mbb = I;
DEBUG(std::cerr << ((Value*)mbb->getBasicBlock())->getName() << ":\n");
for (MachineBasicBlock::iterator mi = mbb->begin(), miEnd = mbb->end();
mi != miEnd; ++mi) {
MachineBasicBlock::iterator mi = mbb->begin(), miEnd = mbb->end();
if (IgnoreFirstInstr) { ++mi; IgnoreFirstInstr = false; }
for (; mi != miEnd; ++mi) {
const TargetInstrDescriptor& tid =
tm_->getInstrInfo()->get(mi->getOpcode());
DEBUG(std::cerr << getInstructionIndex(mi) << "\t" << *mi);