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Use the newly created helper on LiveIntervals.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52013 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2008-06-05 17:22:53 +00:00
parent c4dc132c8a
commit a9efb264b0
1 changed files with 21 additions and 116 deletions
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137
lib/CodeGen/StrongPHIElimination.cpp
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@ -52,8 +52,9 @@ namespace {
// used as operands to another another PHI node
std::set<unsigned> UsedByAnother;
// RenameSets are the sets of operands (and their VNInfo IDs) to a PHI
// (the defining instruction of the key) that can be renamed without copies.
// RenameSets are the is a map from a PHI-defined register
// to the input registers to be coalesced along with the index
// of the input registers.
std::map<unsigned, std::map<unsigned, unsigned> > RenameSets;
// PhiValueNumber holds the ID numbers of the VNs for each phi that we're
@ -466,15 +467,11 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
UsedByAnother.insert(SrcReg);
} else {
// Otherwise, add it to the renaming set
LiveInterval& I = LI.getOrCreateInterval(SrcReg);
// We need to subtract one from the index because live ranges are open
// at the end.
unsigned idx = LI.getMBBEndIdx(P->getOperand(i).getMBB()) - 1;
VNInfo* VN = I.getLiveRangeContaining(idx)->valno;
assert(VN && "No VNInfo for register?");
PHIUnion.insert(std::make_pair(SrcReg, VN->id));
PHIUnion.insert(std::make_pair(SrcReg, idx));
UnionedBlocks.insert(MRI.getVRegDef(SrcReg)->getParent());
}
}
@ -744,22 +741,9 @@ void StrongPHIElimination::ScheduleCopies(MachineBasicBlock* MBB,
// PHI, we don't create multiple overlapping live intervals.
std::set<unsigned> RegHandled;
for (SmallVector<std::pair<unsigned, MachineInstr*>, 4>::iterator I =
InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I) {
if (!RegHandled.count(I->first)) {
LiveInterval& Interval = LI.getOrCreateInterval(I->first);
VNInfo* VN = Interval.getNextValue(
LI.getInstructionIndex(I->second) + LiveIntervals::InstrSlots::DEF,
I->second, LI.getVNInfoAllocator());
VN->hasPHIKill = true;
VN->kills.push_back(LI.getMBBEndIdx(I->second->getParent()));
LiveRange LR(LI.getInstructionIndex(I->second) +
LiveIntervals::InstrSlots::DEF,
LI.getMBBEndIdx(I->second->getParent()) + 1, VN);
Interval.addRange(LR);
RegHandled.insert(I->first);
}
}
InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I)
if (!RegHandled.count(I->first))
LI.addLiveRangeToEndOfBlock(I->first, I->second);
}
/// InsertCopies - insert copies into MBB and all of its successors
@ -794,111 +778,30 @@ void StrongPHIElimination::InsertCopies(MachineBasicBlock* MBB,
Stacks[*I].pop_back();
}
/// ComputeUltimateVN - Assuming we are going to join two live intervals,
/// compute what the resultant value numbers for each value in the input two
/// ranges will be. This is complicated by copies between the two which can
/// and will commonly cause multiple value numbers to be merged into one.
///
/// VN is the value number that we're trying to resolve. InstDefiningValue
/// keeps track of the new InstDefiningValue assignment for the result
/// LiveInterval. ThisFromOther/OtherFromThis are sets that keep track of
/// whether a value in this or other is a copy from the opposite set.
/// ThisValNoAssignments/OtherValNoAssignments keep track of value #'s that have
/// already been assigned.
///
/// ThisFromOther[x] - If x is defined as a copy from the other interval, this
/// contains the value number the copy is from.
///
static unsigned ComputeUltimateVN(VNInfo *VNI,
SmallVector<VNInfo*, 16> &NewVNInfo,
DenseMap<VNInfo*, VNInfo*> &ThisFromOther,
DenseMap<VNInfo*, VNInfo*> &OtherFromThis,
SmallVector<int, 16> &ThisValNoAssignments,
SmallVector<int, 16> &OtherValNoAssignments) {
unsigned VN = VNI->id;
// If the VN has already been computed, just return it.
if (ThisValNoAssignments[VN] >= 0)
return ThisValNoAssignments[VN];
// assert(ThisValNoAssignments[VN] != -2 && "Cyclic case?");
// If this val is not a copy from the other val, then it must be a new value
// number in the destination.
DenseMap<VNInfo*, VNInfo*>::iterator I = ThisFromOther.find(VNI);
if (I == ThisFromOther.end()) {
NewVNInfo.push_back(VNI);
return ThisValNoAssignments[VN] = NewVNInfo.size()-1;
}
VNInfo *OtherValNo = I->second;
// Otherwise, this *is* a copy from the RHS. If the other side has already
// been computed, return it.
if (OtherValNoAssignments[OtherValNo->id] >= 0)
return ThisValNoAssignments[VN] = OtherValNoAssignments[OtherValNo->id];
// Mark this value number as currently being computed, then ask what the
// ultimate value # of the other value is.
ThisValNoAssignments[VN] = -2;
unsigned UltimateVN =
ComputeUltimateVN(OtherValNo, NewVNInfo, OtherFromThis, ThisFromOther,
OtherValNoAssignments, ThisValNoAssignments);
return ThisValNoAssignments[VN] = UltimateVN;
}
void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned secondary,
unsigned secondaryVN) {
unsigned secondaryIdx) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
LiveInterval& LHS = LI.getOrCreateInterval(primary);
LiveInterval& RHS = LI.getOrCreateInterval(secondary);
// Compute the final value assignment, assuming that the live ranges can be
// coalesced.
SmallVector<int, 16> LHSValNoAssignments;
SmallVector<int, 16> RHSValNoAssignments;
SmallVector<VNInfo*, 16> NewVNInfo;
LI.computeNumbering();
LHSValNoAssignments.resize(LHS.getNumValNums(), -1);
RHSValNoAssignments.resize(RHS.getNumValNums(), -1);
NewVNInfo.reserve(LHS.getNumValNums() + RHS.getNumValNums());
for (LiveInterval::vni_iterator I = LHS.vni_begin(), E = LHS.vni_end();
I != E; ++I) {
VNInfo *VNI = *I;
unsigned VN = VNI->id;
if (LHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
continue;
NewVNInfo.push_back(VNI);
LHSValNoAssignments[VN] = NewVNInfo.size()-1;
}
for (LiveInterval::vni_iterator I = RHS.vni_begin(), E = RHS.vni_end();
I != E; ++I) {
VNInfo *VNI = *I;
unsigned VN = VNI->id;
if (RHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
continue;
NewVNInfo.push_back(VNI);
RHSValNoAssignments[VN] = NewVNInfo.size()-1;
}
// If we get here, we know that we can coalesce the live ranges. Ask the
// intervals to coalesce themselves now.
LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo);
LI.removeInterval(secondary);
// The valno that was previously the input to the PHI node
// now has a PHIKill.
LHS.getValNumInfo(RHSValNoAssignments[secondaryVN])->hasPHIKill = true;
const LiveRange* RangeMergingIn = RHS.getLiveRangeContaining(secondaryIdx);
VNInfo* NewVN = LHS.getNextValue(secondaryIdx, RangeMergingIn->valno->copy,
LI.getVNInfoAllocator());
NewVN->hasPHIKill = true;
LiveRange NewRange(RangeMergingIn->start, RangeMergingIn->end, NewVN);
LHS.addRange(NewRange);
RHS.removeRange(RangeMergingIn->start, RangeMergingIn->end, true);
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
LI.dump();
// Compute DFS numbers of each block
computeDFS(Fn);
@ -909,7 +812,7 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
processBlock(I);
// Insert copies
// FIXME: This process should probably preserve LiveVariables
// FIXME: This process should probably preserve LiveIntervals
SmallPtrSet<MachineBasicBlock*, 16> visited;
InsertCopies(Fn.begin(), visited);
@ -961,5 +864,7 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
LI.computeNumbering();
LI.dump();
return true;
}