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Use a faster algorithm for computing MBB live-in registers after register allocation. 

LiveIntervals::findLiveInMBBs has to do a full binary search for each segment.

llvm-svn: 129292
This commit is contained in:
Jakob Stoklund Olesen 2011-04-11 20:01:41 +00:00
parent 56c5ca2ee1
commit 7d05bce70c
1 changed files with 20 additions and 18 deletions
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38
llvm/lib/CodeGen/RegAllocBasic.cpp
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@ -405,29 +405,31 @@ RegAllocBase::spillInterferences(LiveInterval &VirtReg, unsigned PhysReg,
// Add newly allocated physical registers to the MBB live in sets.
void RegAllocBase::addMBBLiveIns(MachineFunction *MF) {
NamedRegionTimer T("MBB Live Ins", TimerGroupName, TimePassesIsEnabled);
typedef SmallVector<MachineBasicBlock*, 8> MBBVec;
MBBVec liveInMBBs;
MachineBasicBlock &entryMBB = *MF->begin();
SlotIndexes *Indexes = LIS->getSlotIndexes();
if (MF->size() <= 1)
return;
LiveIntervalUnion::SegmentIter SI;
for (unsigned PhysReg = 0; PhysReg < PhysReg2LiveUnion.numRegs(); ++PhysReg) {
LiveIntervalUnion &LiveUnion = PhysReg2LiveUnion[PhysReg];
if (LiveUnion.empty())
continue;
for (LiveIntervalUnion::SegmentIter SI = LiveUnion.begin(); SI.valid();
++SI) {
// Find the set of basic blocks which this range is live into...
liveInMBBs.clear();
if (!LIS->findLiveInMBBs(SI.start(), SI.stop(), liveInMBBs)) continue;
// And add the physreg for this interval to their live-in sets.
for (MBBVec::iterator I = liveInMBBs.begin(), E = liveInMBBs.end();
I != E; ++I) {
MachineBasicBlock *MBB = *I;
if (MBB == &entryMBB) continue;
if (MBB->isLiveIn(PhysReg)) continue;
MBB->addLiveIn(PhysReg);
}
MachineFunction::iterator MBB = llvm::next(MF->begin());
MachineFunction::iterator MFE = MF->end();
SlotIndex Start, Stop;
tie(Start, Stop) = Indexes->getMBBRange(MBB);
SI.setMap(LiveUnion.getMap());
SI.find(Start);
while (SI.valid()) {
if (SI.start() <= Start) {
if (!MBB->isLiveIn(PhysReg))
MBB->addLiveIn(PhysReg);
} else if (SI.start() > Stop)
MBB = Indexes->getMBBFromIndex(SI.start());
if (++MBB == MFE)
break;
tie(Start, Stop) = Indexes->getMBBRange(MBB);
SI.advanceTo(Start);
}
}
}