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Allow any MachineBasicBlock (not just the entry block) to have live-in physical

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registers. Make sure liveinterval analysis is correctly creating live ranges
for them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34217 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2007-02-13 01:30:55 +00:00
parent 818d42f1e8
commit 0c9f92e1ff
2 changed files with 41 additions and 47 deletions
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72
lib/CodeGen/LiveIntervalAnalysis.cpp
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@@ -88,28 +88,6 @@ 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()->first;
// 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 and MachineBasicBlocks.
// Initialize MBB indexes to a sentinal.
MBB2IdxMap.resize(mf_->getNumBlockIDs(), ~0U);
@@ -119,6 +97,28 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
MBB != E; ++MBB) {
// Set the MBB2IdxMap entry for this MBB.
MBB2IdxMap[MBB->getNumber()] = MIIndex;
// If this BB 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 (MBB->livein_begin() != MBB->livein_end()) {
unsigned FirstLiveIn = *MBB->livein_begin();
// Find a reg class that contains this live in.
const TargetRegisterClass *RC = 0;
for (MRegisterInfo::regclass_iterator RCI = mri_->regclass_begin(),
RCE = mri_->regclass_end(); RCI != RCE; ++RCI)
if ((*RCI)->contains(FirstLiveIn)) {
RC = *RCI;
break;
}
MachineInstr *OldFirstMI = MBB->begin();
mri_->copyRegToReg(*MBB, MBB->begin(),
FirstLiveIn, FirstLiveIn, RC);
assert(OldFirstMI != MBB->begin() &&
"copyRetToReg didn't insert anything!");
}
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
@@ -129,19 +129,6 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
}
}
// Note intervals due to live-in values.
if (fn.livein_begin() != fn.livein_end()) {
MachineBasicBlock *Entry = fn.begin();
for (MachineFunction::livein_iterator I = fn.livein_begin(),
E = fn.livein_end(); I != E; ++I) {
handlePhysicalRegisterDef(Entry, Entry->begin(), 0,
getOrCreateInterval(I->first), 0);
for (const unsigned* AS = mri_->getAliasSet(I->first); *AS; ++AS)
handlePhysicalRegisterDef(Entry, Entry->begin(), 0,
getOrCreateInterval(*AS), 0);
}
}
computeIntervals();
numIntervals += getNumIntervals();
@@ -691,8 +678,6 @@ void LiveIntervals::computeIntervals() {
DOUT << "********** COMPUTING LIVE INTERVALS **********\n"
<< "********** Function: "
<< ((Value*)mf_->getFunction())->getName() << '\n';
bool IgnoreFirstInstr = mf_->livein_begin() != mf_->livein_end();
// Track the index of the current machine instr.
unsigned MIIndex = 0;
for (MachineFunction::iterator MBBI = mf_->begin(), E = mf_->end();
@@ -701,9 +686,18 @@ void LiveIntervals::computeIntervals() {
DOUT << ((Value*)MBB->getBasicBlock())->getName() << ":\n";
MachineBasicBlock::iterator MI = MBB->begin(), miEnd = MBB->end();
if (IgnoreFirstInstr) {
if (MBB->livein_begin() != MBB->livein_end()) {
// Process live-ins to this BB first.
for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(),
LE = MBB->livein_end(); LI != LE; ++LI) {
handlePhysicalRegisterDef(MBB, MBB->begin(), MIIndex,
getOrCreateInterval(*LI), 0);
for (const unsigned* AS = mri_->getAliasSet(*LI); *AS; ++AS)
handlePhysicalRegisterDef(MBB, MBB->begin(), MIIndex,
getOrCreateInterval(*AS), 0);
}
++MI;
IgnoreFirstInstr = false;
MIIndex += InstrSlots::NUM;
}