StrongPHIElimination.cpp [plain text]
#define DEBUG_TYPE "strongphielim"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterCoalescer.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace {
struct StrongPHIElimination : public MachineFunctionPass {
static char ID; StrongPHIElimination() : MachineFunctionPass(&ID) {}
DenseMap<MachineBasicBlock*,
std::multimap<unsigned, unsigned> > Waiting;
std::map<unsigned, std::vector<unsigned> > Stacks;
std::set<unsigned> UsedByAnother;
std::map<unsigned, std::map<unsigned, MachineBasicBlock*> > RenameSets;
std::map<unsigned, unsigned> PhiValueNumber;
DenseMap<MachineBasicBlock*, unsigned> preorder;
DenseMap<MachineBasicBlock*, unsigned> maxpreorder;
bool runOnMachineFunction(MachineFunction &Fn);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<MachineDominatorTree>();
AU.addRequired<SlotIndexes>();
AU.addPreserved<SlotIndexes>();
AU.addRequired<LiveIntervals>();
AU.addPreserved<LiveIntervals>();
AU.addPreserved<RegisterCoalescer>();
MachineFunctionPass::getAnalysisUsage(AU);
}
virtual void releaseMemory() {
preorder.clear();
maxpreorder.clear();
Waiting.clear();
Stacks.clear();
UsedByAnother.clear();
RenameSets.clear();
}
private:
struct DomForestNode {
private:
std::vector<DomForestNode*> children;
unsigned reg;
void addChild(DomForestNode* DFN) { children.push_back(DFN); }
public:
typedef std::vector<DomForestNode*>::iterator iterator;
DomForestNode(unsigned r, DomForestNode* parent) : reg(r) {
if (parent)
parent->addChild(this);
}
~DomForestNode() {
for (iterator I = begin(), E = end(); I != E; ++I)
delete *I;
}
inline unsigned getReg() { return reg; }
inline DomForestNode::iterator begin() { return children.begin(); }
inline DomForestNode::iterator end() { return children.end(); }
};
void computeDFS(MachineFunction& MF);
void processBlock(MachineBasicBlock* MBB);
std::vector<DomForestNode*> computeDomForest(
std::map<unsigned, MachineBasicBlock*>& instrs,
MachineRegisterInfo& MRI);
void processPHIUnion(MachineInstr* Inst,
std::map<unsigned, MachineBasicBlock*>& PHIUnion,
std::vector<StrongPHIElimination::DomForestNode*>& DF,
std::vector<std::pair<unsigned, unsigned> >& locals);
void ScheduleCopies(MachineBasicBlock* MBB, std::set<unsigned>& pushed);
void InsertCopies(MachineDomTreeNode* MBB,
SmallPtrSet<MachineBasicBlock*, 16>& v);
bool mergeLiveIntervals(unsigned primary, unsigned secondary);
};
}
char StrongPHIElimination::ID = 0;
static RegisterPass<StrongPHIElimination>
X("strong-phi-node-elimination",
"Eliminate PHI nodes for register allocation, intelligently");
const PassInfo *const llvm::StrongPHIEliminationID = &X;
void StrongPHIElimination::computeDFS(MachineFunction& MF) {
SmallPtrSet<MachineDomTreeNode*, 8> frontier;
SmallPtrSet<MachineDomTreeNode*, 8> visited;
unsigned time = 0;
MachineDominatorTree& DT = getAnalysis<MachineDominatorTree>();
MachineDomTreeNode* node = DT.getRootNode();
std::vector<MachineDomTreeNode*> worklist;
worklist.push_back(node);
while (!worklist.empty()) {
MachineDomTreeNode* currNode = worklist.back();
if (!frontier.count(currNode)) {
frontier.insert(currNode);
++time;
preorder.insert(std::make_pair(currNode->getBlock(), time));
}
bool inserted = false;
for (MachineDomTreeNode::iterator I = currNode->begin(), E = currNode->end();
I != E; ++I)
if (!frontier.count(*I) && !visited.count(*I)) {
worklist.push_back(*I);
inserted = true;
break;
}
if (!inserted) {
frontier.erase(currNode);
visited.insert(currNode);
maxpreorder.insert(std::make_pair(currNode->getBlock(), time));
worklist.pop_back();
}
}
}
namespace {
class PreorderSorter {
private:
DenseMap<MachineBasicBlock*, unsigned>& preorder;
MachineRegisterInfo& MRI;
public:
PreorderSorter(DenseMap<MachineBasicBlock*, unsigned>& p,
MachineRegisterInfo& M) : preorder(p), MRI(M) { }
bool operator()(unsigned A, unsigned B) {
if (A == B)
return false;
MachineBasicBlock* ABlock = MRI.getVRegDef(A)->getParent();
MachineBasicBlock* BBlock = MRI.getVRegDef(B)->getParent();
if (preorder[ABlock] < preorder[BBlock])
return true;
else if (preorder[ABlock] > preorder[BBlock])
return false;
return false;
}
};
}
std::vector<StrongPHIElimination::DomForestNode*>
StrongPHIElimination::computeDomForest(
std::map<unsigned, MachineBasicBlock*>& regs,
MachineRegisterInfo& MRI) {
DomForestNode* VirtualRoot = new DomForestNode(0, 0);
maxpreorder.insert(std::make_pair((MachineBasicBlock*)0, ~0UL));
std::vector<unsigned> worklist;
worklist.reserve(regs.size());
for (std::map<unsigned, MachineBasicBlock*>::iterator I = regs.begin(),
E = regs.end(); I != E; ++I)
worklist.push_back(I->first);
PreorderSorter PS(preorder, MRI);
std::sort(worklist.begin(), worklist.end(), PS);
DomForestNode* CurrentParent = VirtualRoot;
std::vector<DomForestNode*> stack;
stack.push_back(VirtualRoot);
for (std::vector<unsigned>::iterator I = worklist.begin(), E = worklist.end();
I != E; ++I) {
unsigned pre = preorder[MRI.getVRegDef(*I)->getParent()];
MachineBasicBlock* parentBlock = CurrentParent->getReg() ?
MRI.getVRegDef(CurrentParent->getReg())->getParent() :
0;
while (pre > maxpreorder[parentBlock]) {
stack.pop_back();
CurrentParent = stack.back();
parentBlock = CurrentParent->getReg() ?
MRI.getVRegDef(CurrentParent->getReg())->getParent() :
0;
}
DomForestNode* child = new DomForestNode(*I, CurrentParent);
stack.push_back(child);
CurrentParent = child;
}
std::vector<DomForestNode*> ret;
ret.insert(ret.end(), VirtualRoot->begin(), VirtualRoot->end());
return ret;
}
static bool isLiveIn(unsigned r, MachineBasicBlock* MBB,
LiveIntervals& LI) {
LiveInterval& I = LI.getOrCreateInterval(r);
SlotIndex idx = LI.getMBBStartIdx(MBB);
return I.liveAt(idx);
}
static bool isLiveOut(unsigned r, MachineBasicBlock* MBB,
LiveIntervals& LI) {
for (MachineBasicBlock::succ_iterator PI = MBB->succ_begin(),
E = MBB->succ_end(); PI != E; ++PI)
if (isLiveIn(r, *PI, LI))
return true;
return false;
}
static bool interferes(unsigned a, unsigned b, MachineBasicBlock* scan,
LiveIntervals& LV, unsigned mode) {
MachineInstr* def = 0;
MachineInstr* kill = 0;
const MachineRegisterInfo* MRI = &scan->getParent()->getRegInfo();
bool interference = false;
for (MachineBasicBlock::iterator MBI = scan->begin(), MBE = scan->end();
MBI != MBE; ++MBI) {
MachineInstr* curr = MBI;
if (mode == 0) {
if (curr == MRI->getVRegDef(a)) {
if (!def) {
def = curr;
} else if (!kill) {
interference = true;
break;
} else {
interference = false;
break;
}
} else if (curr == MRI->getVRegDef(b)) {
if (!def) {
def = curr;
} else if (!kill) {
interference = true;
break;
} else {
interference = false;
break;
}
} else if (curr->killsRegister(a)) {
if (def == MRI->getVRegDef(a)) {
kill = curr;
} else if (curr->killsRegister(b)) {
if (def == MRI->getVRegDef(b)) {
kill = curr;
}
}
}
} else if (mode == 1) {
if (curr == MRI->getVRegDef(b)) {
if (!kill) {
interference = true;
break;
} else {
interference = false;
break;
}
} else if (curr->killsRegister(a)) {
kill = curr;
}
} else if (mode == 2) {
if (curr == MRI->getVRegDef(a)) {
if (!kill) {
interference = true;
break;
} else {
interference = false;
break;
}
} else if (curr->killsRegister(b)) {
kill = curr;
}
}
}
return interference;
}
void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
MachineRegisterInfo& MRI = MBB->getParent()->getRegInfo();
std::set<unsigned> ProcessedNames;
MachineBasicBlock::iterator P = MBB->begin();
while (P != MBB->end() && P->isPHI()) {
unsigned DestReg = P->getOperand(0).getReg();
if (P->registerDefIsDead(DestReg)) {
++P;
continue;
}
LiveInterval& PI = LI.getOrCreateInterval(DestReg);
SlotIndex pIdx = LI.getInstructionIndex(P).getDefIndex();
VNInfo* PVN = PI.getLiveRangeContaining(pIdx)->valno;
PhiValueNumber.insert(std::make_pair(DestReg, PVN->id));
std::map<unsigned, MachineBasicBlock*> PHIUnion;
SmallPtrSet<MachineBasicBlock*, 8> UnionedBlocks;
for (int i = P->getNumOperands() - 1; i >= 2; i-=2) {
unsigned SrcReg = P->getOperand(i-1).getReg();
if (SrcReg == DestReg) {
ProcessedNames.insert(SrcReg);
continue;
}
MachineInstr* DefMI = MRI.getVRegDef(SrcReg);
if (DefMI->isImplicitDef())
ProcessedNames.insert(SrcReg);
if (isLiveIn(SrcReg, P->getParent(), LI) ||
isLiveOut(P->getOperand(0).getReg(),
MRI.getVRegDef(SrcReg)->getParent(), LI) ||
( MRI.getVRegDef(SrcReg)->isPHI() &&
isLiveIn(P->getOperand(0).getReg(),
MRI.getVRegDef(SrcReg)->getParent(), LI) ) ||
ProcessedNames.count(SrcReg) ||
UnionedBlocks.count(MRI.getVRegDef(SrcReg)->getParent())) {
MachineBasicBlock* From = P->getOperand(i).getMBB();
Waiting[From].insert(std::make_pair(SrcReg, DestReg));
UsedByAnother.insert(SrcReg);
} else {
PHIUnion.insert(std::make_pair(SrcReg,P->getOperand(i).getMBB()));
UnionedBlocks.insert(MRI.getVRegDef(SrcReg)->getParent());
}
}
std::vector<StrongPHIElimination::DomForestNode*> DF =
computeDomForest(PHIUnion, MRI);
std::vector<std::pair<unsigned, unsigned> > localInterferences;
processPHIUnion(P, PHIUnion, DF, localInterferences);
for (std::map<unsigned, MachineBasicBlock*>::iterator I = PHIUnion.begin(),
E = PHIUnion.end(); I != E; ++I)
if (MRI.getVRegDef(I->first)->getParent() == P->getParent())
localInterferences.push_back(std::make_pair(I->first,
P->getOperand(0).getReg()));
for (std::vector<std::pair<unsigned, unsigned> >::iterator I =
localInterferences.begin(), E = localInterferences.end(); I != E; ++I) {
std::pair<unsigned, unsigned> p = *I;
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
MachineBasicBlock* scan = 0;
unsigned mode = 0;
if (MRI.getVRegDef(p.first)->getParent() ==
MRI.getVRegDef(p.second)->getParent()) {
scan = MRI.getVRegDef(p.first)->getParent();
mode = 0; } else if (MDT.dominates(MRI.getVRegDef(p.first)->getParent(),
MRI.getVRegDef(p.second)->getParent())) {
scan = MRI.getVRegDef(p.second)->getParent();
mode = 1; } else {
scan = MRI.getVRegDef(p.first)->getParent();
mode = 2; }
if (interferes(p.first, p.second, scan, LI, mode)) {
for (int i = P->getNumOperands() - 1; i >= 2; i-=2) {
if (P->getOperand(i-1).getReg() == p.first) {
unsigned SrcReg = p.first;
MachineBasicBlock* From = P->getOperand(i).getMBB();
Waiting[From].insert(std::make_pair(SrcReg,
P->getOperand(0).getReg()));
UsedByAnother.insert(SrcReg);
PHIUnion.erase(SrcReg);
}
}
}
}
for (std::map<unsigned, MachineBasicBlock*>::iterator QI = PHIUnion.begin(),
QE = PHIUnion.end(); QI != QE; ++QI) {
DEBUG(dbgs() << "Adding Renaming: " << QI->first << " -> "
<< P->getOperand(0).getReg() << "\n");
}
RenameSets.insert(std::make_pair(P->getOperand(0).getReg(), PHIUnion));
for (std::map<unsigned, MachineBasicBlock*>::iterator I = PHIUnion.begin(),
E = PHIUnion.end(); I != E; ++I)
ProcessedNames.insert(I->first);
++P;
}
}
void StrongPHIElimination::processPHIUnion(MachineInstr* Inst,
std::map<unsigned, MachineBasicBlock*>& PHIUnion,
std::vector<StrongPHIElimination::DomForestNode*>& DF,
std::vector<std::pair<unsigned, unsigned> >& locals) {
std::vector<DomForestNode*> worklist(DF.begin(), DF.end());
SmallPtrSet<DomForestNode*, 4> visited;
MachineRegisterInfo& MRI = Inst->getParent()->getParent()->getRegInfo();
LiveIntervals& LI = getAnalysis<LiveIntervals>();
unsigned DestReg = Inst->getOperand(0).getReg();
while (!worklist.empty()) {
DomForestNode* DFNode = worklist.back();
visited.insert(DFNode);
bool inserted = false;
for (DomForestNode::iterator CI = DFNode->begin(), CE = DFNode->end();
CI != CE; ++CI) {
DomForestNode* child = *CI;
if (isLiveOut(DFNode->getReg(),
MRI.getVRegDef(child->getReg())->getParent(), LI)) {
for (int i = Inst->getNumOperands() - 1; i >= 2; i-=2) {
if (Inst->getOperand(i-1).getReg() == DFNode->getReg()) {
unsigned SrcReg = DFNode->getReg();
MachineBasicBlock* From = Inst->getOperand(i).getMBB();
Waiting[From].insert(std::make_pair(SrcReg, DestReg));
UsedByAnother.insert(SrcReg);
PHIUnion.erase(SrcReg);
}
}
} else if (isLiveIn(DFNode->getReg(),
MRI.getVRegDef(child->getReg())->getParent(), LI) ||
MRI.getVRegDef(DFNode->getReg())->getParent() ==
MRI.getVRegDef(child->getReg())->getParent()) {
locals.push_back(std::make_pair(DFNode->getReg(), child->getReg()));
}
if (!visited.count(child)) {
worklist.push_back(child);
inserted = true;
}
}
if (!inserted) worklist.pop_back();
}
}
void StrongPHIElimination::ScheduleCopies(MachineBasicBlock* MBB,
std::set<unsigned>& pushed) {
std::multimap<unsigned, unsigned>& copy_set= Waiting[MBB];
std::multimap<unsigned, unsigned> worklist;
std::map<unsigned, unsigned> map;
for (std::multimap<unsigned, unsigned>::iterator I = copy_set.begin(),
E = copy_set.end(); I != E; ) {
map.insert(std::make_pair(I->first, I->first));
map.insert(std::make_pair(I->second, I->second));
if (!UsedByAnother.count(I->second)) {
worklist.insert(*I);
std::multimap<unsigned, unsigned>::iterator OI = I;
++I;
copy_set.erase(OI);
} else {
++I;
}
}
LiveIntervals& LI = getAnalysis<LiveIntervals>();
MachineFunction* MF = MBB->getParent();
MachineRegisterInfo& MRI = MF->getRegInfo();
const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
SmallVector<std::pair<unsigned, MachineInstr*>, 4> InsertedPHIDests;
while (!worklist.empty() || !copy_set.empty()) {
while (!worklist.empty()) {
std::multimap<unsigned, unsigned>::iterator WI = worklist.begin();
std::pair<unsigned, unsigned> curr = *WI;
worklist.erase(WI);
const TargetRegisterClass *RC = MF->getRegInfo().getRegClass(curr.first);
if (isLiveOut(curr.second, MBB, LI)) {
unsigned t = MF->getRegInfo().createVirtualRegister(RC);
MachineBasicBlock::iterator PI = MRI.getVRegDef(curr.second);
TII->copyRegToReg(*PI->getParent(), PI, t,
curr.second, RC, RC);
DEBUG(dbgs() << "Inserted copy from " << curr.second << " to " << t
<< "\n");
Stacks[curr.second].push_back(t);
pushed.insert(curr.second);
InsertedPHIDests.push_back(std::make_pair(t, --PI));
}
TII->copyRegToReg(*MBB, MBB->getFirstTerminator(), curr.second,
map[curr.first], RC, RC);
map[curr.first] = curr.second;
DEBUG(dbgs() << "Inserted copy from " << curr.first << " to "
<< curr.second << "\n");
MachineBasicBlock::iterator MI = MBB->getFirstTerminator();
InsertedPHIDests.push_back(std::make_pair(curr.second, --MI));
for (std::multimap<unsigned, unsigned>::iterator I = copy_set.begin(),
E = copy_set.end(); I != E; )
if (curr.first == I->second) {
std::pair<unsigned, unsigned> temp = *I;
worklist.insert(temp);
std::multimap<unsigned, unsigned>::iterator OI = I;
++I;
copy_set.erase(OI);
break;
} else {
++I;
}
}
if (!copy_set.empty()) {
std::multimap<unsigned, unsigned>::iterator CI = copy_set.begin();
std::pair<unsigned, unsigned> curr = *CI;
worklist.insert(curr);
copy_set.erase(CI);
LiveInterval& I = LI.getInterval(curr.second);
MachineBasicBlock::iterator term = MBB->getFirstTerminator();
SlotIndex endIdx = SlotIndex();
if (term != MBB->end())
endIdx = LI.getInstructionIndex(term);
else
endIdx = LI.getMBBEndIdx(MBB);
if (I.liveAt(endIdx)) {
const TargetRegisterClass *RC =
MF->getRegInfo().getRegClass(curr.first);
unsigned t = MF->getRegInfo().createVirtualRegister(RC);
TII->copyRegToReg(*MBB, MBB->getFirstTerminator(), t,
curr.second, RC, RC);
map[curr.second] = t;
MachineBasicBlock::iterator TI = MBB->getFirstTerminator();
InsertedPHIDests.push_back(std::make_pair(t, --TI));
}
}
}
LI.renumber();
std::set<unsigned> RegHandled;
for (SmallVector<std::pair<unsigned, MachineInstr*>, 4>::iterator I =
InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I) {
if (RegHandled.insert(I->first).second) {
LiveInterval& Int = LI.getOrCreateInterval(I->first);
SlotIndex instrIdx = LI.getInstructionIndex(I->second);
if (Int.liveAt(instrIdx.getDefIndex()))
Int.removeRange(instrIdx.getDefIndex(),
LI.getMBBEndIdx(I->second->getParent()).getNextSlot(),
true);
LiveRange R = LI.addLiveRangeToEndOfBlock(I->first, I->second);
R.valno->setCopy(I->second);
R.valno->def = LI.getInstructionIndex(I->second).getDefIndex();
}
}
}
void StrongPHIElimination::InsertCopies(MachineDomTreeNode* MDTN,
SmallPtrSet<MachineBasicBlock*, 16>& visited) {
MachineBasicBlock* MBB = MDTN->getBlock();
visited.insert(MBB);
std::set<unsigned> pushed;
LiveIntervals& LI = getAnalysis<LiveIntervals>();
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
if (I->isPHI())
continue;
for (unsigned i = 0; i < I->getNumOperands(); ++i)
if (I->getOperand(i).isReg() &&
Stacks[I->getOperand(i).getReg()].size()) {
LiveInterval& OldInt = LI.getInterval(I->getOperand(i).getReg());
LiveInterval::iterator OldLR =
OldInt.FindLiveRangeContaining(LI.getInstructionIndex(I).getUseIndex());
if (OldLR != OldInt.end())
OldInt.removeRange(*OldLR, true);
I->getOperand(i).setReg(Stacks[I->getOperand(i).getReg()].back());
LiveInterval& Int = LI.getInterval(I->getOperand(i).getReg());
VNInfo* FirstVN = *Int.vni_begin();
FirstVN->setHasPHIKill(false);
if (I->getOperand(i).isKill())
FirstVN->addKill(LI.getInstructionIndex(I).getUseIndex());
LiveRange LR (LI.getMBBStartIdx(I->getParent()),
LI.getInstructionIndex(I).getUseIndex().getNextSlot(),
FirstVN);
Int.addRange(LR);
}
}
ScheduleCopies(MBB, pushed);
for (MachineDomTreeNode::iterator I = MDTN->begin(),
E = MDTN->end(); I != E; ++I)
if (!visited.count((*I)->getBlock()))
InsertCopies(*I, visited);
for (std::set<unsigned>::iterator I = pushed.begin(),
E = pushed.end(); I != E; ++I)
Stacks[*I].pop_back();
}
bool StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned secondary) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
LiveInterval& LHS = LI.getOrCreateInterval(primary);
LiveInterval& RHS = LI.getOrCreateInterval(secondary);
LI.renumber();
DenseMap<VNInfo*, VNInfo*> VNMap;
for (LiveInterval::iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
LiveRange R = *I;
SlotIndex Start = R.start;
SlotIndex End = R.end;
if (LHS.getLiveRangeContaining(Start))
return false;
if (LHS.getLiveRangeContaining(End))
return false;
LiveInterval::iterator RI = std::upper_bound(LHS.begin(), LHS.end(), R);
if (RI != LHS.end() && RI->start < End)
return false;
}
for (LiveInterval::iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
LiveRange R = *I;
VNInfo* OldVN = R.valno;
VNInfo*& NewVN = VNMap[OldVN];
if (!NewVN) {
NewVN = LHS.createValueCopy(OldVN, LI.getVNInfoAllocator());
}
LiveRange LR (R.start, R.end, NewVN);
LHS.addRange(LR);
}
LI.removeInterval(RHS.reg);
return true;
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
computeDFS(Fn);
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
if (!I->empty() && I->begin()->isPHI())
processBlock(I);
std::set<unsigned> seen;
typedef std::map<unsigned, std::map<unsigned, MachineBasicBlock*> >
RenameSetType;
for (RenameSetType::iterator I = RenameSets.begin(), E = RenameSets.end();
I != E; ++I) {
for (std::map<unsigned, MachineBasicBlock*>::iterator
OI = I->second.begin(), OE = I->second.end(); OI != OE; ) {
if (!seen.count(OI->first)) {
seen.insert(OI->first);
++OI;
} else {
Waiting[OI->second].insert(std::make_pair(OI->first, I->first));
unsigned reg = OI->first;
++OI;
I->second.erase(reg);
DEBUG(dbgs() << "Removing Renaming: " << reg << " -> " << I->first
<< "\n");
}
}
}
SmallPtrSet<MachineBasicBlock*, 16> visited;
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
InsertCopies(MDT.getRootNode(), visited);
for (RenameSetType::iterator I = RenameSets.begin(), E = RenameSets.end();
I != E; ++I)
while (I->second.size()) {
std::map<unsigned, MachineBasicBlock*>::iterator SI = I->second.begin();
DEBUG(dbgs() << "Renaming: " << SI->first << " -> " << I->first << "\n");
if (SI->first != I->first) {
if (mergeLiveIntervals(I->first, SI->first)) {
Fn.getRegInfo().replaceRegWith(SI->first, I->first);
if (RenameSets.count(SI->first)) {
I->second.insert(RenameSets[SI->first].begin(),
RenameSets[SI->first].end());
RenameSets.erase(SI->first);
}
} else {
const TargetInstrInfo *TII = Fn.getTarget().getInstrInfo();
const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(I->first);
TII->copyRegToReg(*SI->second, SI->second->getFirstTerminator(),
I->first, SI->first, RC, RC);
LI.renumber();
LiveInterval& Int = LI.getOrCreateInterval(I->first);
SlotIndex instrIdx =
LI.getInstructionIndex(--SI->second->getFirstTerminator());
if (Int.liveAt(instrIdx.getDefIndex()))
Int.removeRange(instrIdx.getDefIndex(),
LI.getMBBEndIdx(SI->second).getNextSlot(), true);
LiveRange R = LI.addLiveRangeToEndOfBlock(I->first,
--SI->second->getFirstTerminator());
R.valno->setCopy(--SI->second->getFirstTerminator());
R.valno->def = instrIdx.getDefIndex();
DEBUG(dbgs() << "Renaming failed: " << SI->first << " -> "
<< I->first << "\n");
}
}
LiveInterval& Int = LI.getOrCreateInterval(I->first);
const LiveRange* LR =
Int.getLiveRangeContaining(LI.getMBBEndIdx(SI->second));
LR->valno->setHasPHIKill(true);
I->second.erase(SI->first);
}
std::vector<MachineInstr*> phis;
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
for (MachineBasicBlock::iterator BI = I->begin(), BE = I->end();
BI != BE; ++BI)
if (BI->isPHI())
phis.push_back(BI);
}
for (std::vector<MachineInstr*>::iterator I = phis.begin(), E = phis.end();
I != E; ) {
MachineInstr* PInstr = *(I++);
unsigned DestReg = PInstr->getOperand(0).getReg();
LiveInterval& PI = LI.getInterval(DestReg);
if (PInstr->registerDefIsDead(DestReg)) {
if (PI.containsOneValue()) {
LI.removeInterval(DestReg);
} else {
SlotIndex idx = LI.getInstructionIndex(PInstr).getDefIndex();
PI.removeRange(*PI.getLiveRangeContaining(idx), true);
}
} else {
for (unsigned i = 1; i < PInstr->getNumOperands(); i += 2) {
unsigned reg = PInstr->getOperand(i).getReg();
MachineBasicBlock* MBB = PInstr->getOperand(i+1).getMBB();
LiveInterval& InputI = LI.getInterval(reg);
if (MBB != PInstr->getParent() &&
InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())) &&
InputI.expiredAt(LI.getInstructionIndex(PInstr).getNextIndex()))
InputI.removeRange(LI.getMBBStartIdx(PInstr->getParent()),
LI.getInstructionIndex(PInstr),
true);
}
SlotIndex idx = LI.getInstructionIndex(PInstr).getDefIndex();
const LiveRange* PLR = PI.getLiveRangeContaining(idx);
PLR->valno->setIsPHIDef(true);
LiveRange R (LI.getMBBStartIdx(PInstr->getParent()),
PLR->start, PLR->valno);
PI.addRange(R);
}
LI.RemoveMachineInstrFromMaps(PInstr);
PInstr->eraseFromParent();
}
LI.renumber();
return true;
}