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LiveIntervalAnalysis: Cleanup computeDeadValues

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- This also fixes a bug introduced in r223880 where values were not
  correctly marked as Dead anymore.
- Cleanup computeDeadValues(): split up SubRange code variant, simplify
  arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224538 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matthias Braun
2014-12-18 19:58:52 +00:00
parent a75626b56b
commit b82636bb80
3 changed files with 48 additions and 35 deletions
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57
lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -193,7 +193,7 @@ void LiveIntervals::computeVirtRegInterval(LiveInterval &LI) {
assert(LI.empty() && "Should only compute empty intervals.");
LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
LRCalc->calculate(LI);
computeDeadValues(LI, LI);
computeDeadValues(LI, nullptr);
}
void LiveIntervals::computeVirtRegs() {
@ -433,49 +433,46 @@ bool LiveIntervals::shrinkToUses(LiveInterval *li,
createSegmentsForValues(NewLR, make_range(li->vni_begin(), li->vni_end()));
extendSegmentsToUses(NewLR, *Indexes, WorkList, *li);
// Handle dead values.
bool CanSeparate;
computeDeadValues(NewLR, *li, &CanSeparate, li->reg, dead);
// Move the trimmed segments back.
li->segments.swap(NewLR.segments);
// Handle dead values.
bool CanSeparate = computeDeadValues(*li, dead);
DEBUG(dbgs() << "Shrunk: " << *li << '\n');
return CanSeparate;
}
void LiveIntervals::computeDeadValues(LiveRange &Segments, LiveRange &LR,
bool *CanSeparateRes, unsigned Reg,
bool LiveIntervals::computeDeadValues(LiveInterval &LI,
SmallVectorImpl<MachineInstr*> *dead) {
bool CanSeparate = false;
for (auto VNI : LR.valnos) {
bool PHIRemoved = false;
for (auto VNI : LI.valnos) {
if (VNI->isUnused())
continue;
LiveRange::iterator LRI = Segments.FindSegmentContaining(VNI->def);
assert(LRI != Segments.end() && "Missing segment for PHI");
if (LRI->end != VNI->def.getDeadSlot())
LiveRange::iterator I = LI.FindSegmentContaining(VNI->def);
assert(I != LI.end() && "Missing segment for VNI");
if (I->end != VNI->def.getDeadSlot())
continue;
if (VNI->isPHIDef()) {
// This is a dead PHI. Remove it.
VNI->markUnused();
Segments.removeSegment(LRI->start, LRI->end);
LI.removeSegment(I);
DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n");
CanSeparate = true;
} else if (dead != nullptr) {
PHIRemoved = true;
} else {
// This is a dead def. Make sure the instruction knows.
MachineInstr *MI = getInstructionFromIndex(VNI->def);
assert(MI && "No instruction defining live value");
MI->addRegisterDead(Reg, TRI);
MI->addRegisterDead(LI.reg, TRI);
if (dead && MI->allDefsAreDead()) {
DEBUG(dbgs() << "All defs dead: " << VNI->def << '\t' << *MI);
dead->push_back(MI);
}
}
}
if (CanSeparateRes != nullptr)
*CanSeparateRes = CanSeparate;
return PHIRemoved;
}
bool LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, unsigned Reg)
void LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, unsigned Reg)
{
DEBUG(dbgs() << "Shrink: " << SR << '\n');
assert(TargetRegisterInfo::isVirtualRegister(Reg)
@ -522,14 +519,26 @@ bool LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, unsigned Reg)
createSegmentsForValues(NewLR, make_range(SR.vni_begin(), SR.vni_end()));
extendSegmentsToUses(NewLR, *Indexes, WorkList, SR);
// Handle dead values.
bool CanSeparate;
computeDeadValues(NewLR, SR, &CanSeparate);
// Move the trimmed ranges back.
SR.segments.swap(NewLR.segments);
// Remove dead PHI value numbers
for (auto VNI : SR.valnos) {
if (VNI->isUnused())
continue;
const LiveRange::Segment *Segment = SR.getSegmentContaining(VNI->def);
assert(Segment != nullptr && "Missing segment for VNI");
if (Segment->end != VNI->def.getDeadSlot())
continue;
if (VNI->isPHIDef()) {
// This is a dead PHI. Remove it.
VNI->markUnused();
SR.removeSegment(*Segment);
DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n");
}
}
DEBUG(dbgs() << "Shrunk: " << SR << '\n');
return CanSeparate;
}
void LiveIntervals::extendToIndices(LiveRange &LR,