#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterCoalescer.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace {
- struct VISIBILITY_HIDDEN StrongPHIElimination : public MachineFunctionPass {
+ struct StrongPHIElimination : public MachineFunctionPass {
static char ID; // Pass identification, replacement for typeid
- StrongPHIElimination() : MachineFunctionPass(&ID) {}
+ StrongPHIElimination() : MachineFunctionPass(ID) {}
// Waiting stores, for each MBB, the set of copies that need to
// be inserted into that MBB
DenseMap<MachineBasicBlock*,
- std::map<unsigned, unsigned> > Waiting;
+ std::multimap<unsigned, unsigned> > Waiting;
// Stacks holds the renaming stack for each register
std::map<unsigned, std::vector<unsigned> > Stacks;
// Registers in UsedByAnother are PHI nodes that are themselves
- // used as operands to another another PHI node
+ // used as operands to another PHI node
std::set<unsigned> UsedByAnother;
// RenameSets are the is a map from a PHI-defined register
bool runOnMachineFunction(MachineFunction &Fn);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
AU.addRequired<MachineDominatorTree>();
+ AU.addRequired<SlotIndexes>();
+ AU.addPreserved<SlotIndexes>();
AU.addRequired<LiveIntervals>();
// TODO: Actually make this true.
void ScheduleCopies(MachineBasicBlock* MBB, std::set<unsigned>& pushed);
void InsertCopies(MachineDomTreeNode* MBB,
SmallPtrSet<MachineBasicBlock*, 16>& v);
- void mergeLiveIntervals(unsigned primary, unsigned secondary);
+ bool mergeLiveIntervals(unsigned primary, unsigned secondary);
};
}
X("strong-phi-node-elimination",
"Eliminate PHI nodes for register allocation, intelligently");
-const PassInfo *const llvm::StrongPHIEliminationID = &X;
+char &llvm::StrongPHIEliminationID = StrongPHIElimination::ID;
/// computeDFS - Computes the DFS-in and DFS-out numbers of the dominator tree
/// of the given MachineFunction. These numbers are then used in other parts
static bool isLiveIn(unsigned r, MachineBasicBlock* MBB,
LiveIntervals& LI) {
LiveInterval& I = LI.getOrCreateInterval(r);
- unsigned idx = LI.getMBBStartIdx(MBB);
- return I.liveBeforeAndAt(idx);
+ SlotIndex idx = LI.getMBBStartIdx(MBB);
+ return I.liveAt(idx);
}
/// isLiveOut - help method that determines, from a regno, if a register is
// Iterate over all the PHI nodes in this block
MachineBasicBlock::iterator P = MBB->begin();
- while (P != MBB->end() && P->getOpcode() == TargetInstrInfo::PHI) {
+ while (P != MBB->end() && P->isPHI()) {
unsigned DestReg = P->getOperand(0).getReg();
-
// Don't both doing PHI elimination for dead PHI's.
if (P->registerDefIsDead(DestReg)) {
}
LiveInterval& PI = LI.getOrCreateInterval(DestReg);
- unsigned pIdx = LI.getDefIndex(LI.getInstructionIndex(P));
+ SlotIndex pIdx = LI.getInstructionIndex(P).getDefIndex();
VNInfo* PVN = PI.getLiveRangeContaining(pIdx)->valno;
PhiValueNumber.insert(std::make_pair(DestReg, PVN->id));
ProcessedNames.insert(SrcReg);
continue;
}
+
+ // We don't need to insert copies for implicit_defs.
+ MachineInstr* DefMI = MRI.getVRegDef(SrcReg);
+ if (DefMI->isImplicitDef())
+ ProcessedNames.insert(SrcReg);
// Check for trivial interferences via liveness information, allowing us
// to avoid extra work later. Any registers that interfere cannot both
if (isLiveIn(SrcReg, P->getParent(), LI) ||
isLiveOut(P->getOperand(0).getReg(),
MRI.getVRegDef(SrcReg)->getParent(), LI) ||
- ( MRI.getVRegDef(SrcReg)->getOpcode() == TargetInstrInfo::PHI &&
+ ( MRI.getVRegDef(SrcReg)->isPHI() &&
isLiveIn(P->getOperand(0).getReg(),
MRI.getVRegDef(SrcReg)->getParent(), LI) ) ||
ProcessedNames.count(SrcReg) ||
// Add the renaming set for this PHI node to our overall renaming information
for (std::map<unsigned, MachineBasicBlock*>::iterator QI = PHIUnion.begin(),
QE = PHIUnion.end(); QI != QE; ++QI) {
- DOUT << "Adding Renaming: " << QI->first << " -> "
- << P->getOperand(0).getReg() << "\n";
+ DEBUG(dbgs() << "Adding Renaming: " << QI->first << " -> "
+ << P->getOperand(0).getReg() << "\n");
}
RenameSets.insert(std::make_pair(P->getOperand(0).getReg(), PHIUnion));
void StrongPHIElimination::ScheduleCopies(MachineBasicBlock* MBB,
std::set<unsigned>& pushed) {
// FIXME: This function needs to update LiveIntervals
- std::map<unsigned, unsigned>& copy_set= Waiting[MBB];
+ std::multimap<unsigned, unsigned>& copy_set= Waiting[MBB];
- std::map<unsigned, unsigned> worklist;
+ std::multimap<unsigned, unsigned> worklist;
std::map<unsigned, unsigned> map;
// Setup worklist of initial copies
- for (std::map<unsigned, unsigned>::iterator I = copy_set.begin(),
+ 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));
worklist.insert(*I);
// Avoid iterator invalidation
- unsigned first = I->first;
+ std::multimap<unsigned, unsigned>::iterator OI = I;
++I;
- copy_set.erase(first);
+ copy_set.erase(OI);
} else {
++I;
}
// Iterate over the worklist, inserting copies
while (!worklist.empty() || !copy_set.empty()) {
while (!worklist.empty()) {
- std::pair<unsigned, unsigned> curr = *worklist.begin();
- worklist.erase(curr.first);
+ 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);
// Insert copy from curr.second to a temporary at
// the Phi defining curr.second
MachineBasicBlock::iterator PI = MRI.getVRegDef(curr.second);
- TII->copyRegToReg(*PI->getParent(), PI, t,
- curr.second, RC, RC);
+ BuildMI(*PI->getParent(), PI, DebugLoc(), TII->get(TargetOpcode::COPY),
+ t).addReg(curr.second);
+ DEBUG(dbgs() << "Inserted copy from " << curr.second << " to " << t
+ << "\n");
// Push temporary on Stacks
Stacks[curr.second].push_back(t);
}
// Insert copy from map[curr.first] to curr.second
- TII->copyRegToReg(*MBB, MBB->getFirstTerminator(), curr.second,
- map[curr.first], RC, RC);
+ BuildMI(*MBB, MBB->getFirstTerminator(), DebugLoc(),
+ TII->get(TargetOpcode::COPY), curr.second).addReg(map[curr.first]);
map[curr.first] = curr.second;
+ DEBUG(dbgs() << "Inserted copy from " << curr.first << " to "
+ << curr.second << "\n");
// Push this copy onto InsertedPHICopies so we can
// update LiveIntervals with it.
InsertedPHIDests.push_back(std::make_pair(curr.second, --MI));
// If curr.first is a destination in copy_set...
- for (std::map<unsigned, unsigned>::iterator I = copy_set.begin(),
+ 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);
// Avoid iterator invalidation
+ std::multimap<unsigned, unsigned>::iterator OI = I;
++I;
- copy_set.erase(temp.first);
- worklist.insert(temp);
+ copy_set.erase(OI);
break;
} else {
}
if (!copy_set.empty()) {
- std::pair<unsigned, unsigned> curr = *copy_set.begin();
- copy_set.erase(curr.first);
+ 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();
- unsigned endIdx = 0;
+ SlotIndex endIdx = SlotIndex();
if (term != MBB->end())
endIdx = LI.getInstructionIndex(term);
else
// Insert a copy from dest to a new temporary t at the end of b
unsigned t = MF->getRegInfo().createVirtualRegister(RC);
- TII->copyRegToReg(*MBB, MBB->getFirstTerminator(), t,
- curr.second, RC, RC);
+ BuildMI(*MBB, MBB->getFirstTerminator(), DebugLoc(),
+ TII->get(TargetOpcode::COPY), t).addReg(curr.second);
map[curr.second] = t;
MachineBasicBlock::iterator TI = MBB->getFirstTerminator();
// Renumber the instructions so that we can perform the index computations
// needed to create new live intervals.
- LI.computeNumbering();
+ LI.renumber();
// For copies that we inserted at the ends of predecessors, we construct
// live intervals. This is pretty easy, since we know that the destination
InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I) {
if (RegHandled.insert(I->first).second) {
LiveInterval& Int = LI.getOrCreateInterval(I->first);
- unsigned instrIdx = LI.getInstructionIndex(I->second);
- if (Int.liveAt(LiveIntervals::getDefIndex(instrIdx)))
- Int.removeRange(LiveIntervals::getDefIndex(instrIdx),
- LI.getMBBEndIdx(I->second->getParent())+1,
+ 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->copy = I->second;
- R.valno->def =
- LiveIntervals::getDefIndex(LI.getInstructionIndex(I->second));
+ R.valno->setCopy(I->second);
+ R.valno->def = LI.getInstructionIndex(I->second).getDefIndex();
}
}
}
// Rewrite register uses from Stacks
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end();
I != E; ++I) {
- if (I->getOpcode() == TargetInstrInfo::PHI)
+ if (I->isPHI())
continue;
for (unsigned i = 0; i < I->getNumOperands(); ++i)
- if (I->getOperand(i).isRegister() &&
+ if (I->getOperand(i).isReg() &&
Stacks[I->getOperand(i).getReg()].size()) {
// Remove the live range for the old vreg.
LiveInterval& OldInt = LI.getInterval(I->getOperand(i).getReg());
- LiveInterval::iterator OldLR = OldInt.FindLiveRangeContaining(
- LiveIntervals::getUseIndex(LI.getInstructionIndex(I)));
+ LiveInterval::iterator OldLR =
+ OldInt.FindLiveRangeContaining(LI.getInstructionIndex(I).getUseIndex());
if (OldLR != OldInt.end())
OldInt.removeRange(*OldLR, true);
// Add a live range for the new vreg
LiveInterval& Int = LI.getInterval(I->getOperand(i).getReg());
VNInfo* FirstVN = *Int.vni_begin();
- FirstVN->hasPHIKill = false;
- if (I->getOperand(i).isKill())
- FirstVN->kills.push_back(
- LiveIntervals::getUseIndex(LI.getInstructionIndex(I)));
-
+ FirstVN->setHasPHIKill(false);
LiveRange LR (LI.getMBBStartIdx(I->getParent()),
- LiveIntervals::getUseIndex(LI.getInstructionIndex(I)),
+ LI.getInstructionIndex(I).getUseIndex().getNextSlot(),
FirstVN);
Int.addRange(LR);
Stacks[*I].pop_back();
}
-void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
+bool StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned secondary) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
LiveInterval& LHS = LI.getOrCreateInterval(primary);
LiveInterval& RHS = LI.getOrCreateInterval(secondary);
- LI.computeNumbering();
+ LI.renumber();
DenseMap<VNInfo*, VNInfo*> VNMap;
for (LiveInterval::iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
LiveRange R = *I;
- unsigned Start = R.start;
- unsigned End = R.end;
- if (LHS.liveAt(Start))
- LHS.removeRange(Start, End, true);
+ SlotIndex Start = R.start;
+ SlotIndex End = R.end;
+ if (LHS.getLiveRangeContaining(Start))
+ return false;
- if (const LiveRange* ER = LHS.getLiveRangeContaining(End))
- End = ER->start;
+ if (LHS.getLiveRangeContaining(End))
+ return false;
LiveInterval::iterator RI = std::upper_bound(LHS.begin(), LHS.end(), R);
if (RI != LHS.end() && RI->start < End)
- End = RI->start;
-
- if (Start != End) {
- VNInfo* OldVN = R.valno;
- VNInfo*& NewVN = VNMap[OldVN];
- if (!NewVN) {
- NewVN = LHS.getNextValue(OldVN->def,
- OldVN->copy,
- LI.getVNInfoAllocator());
- NewVN->kills = OldVN->kills;
- }
-
- LiveRange LR (Start, End, NewVN);
- LHS.addRange(LR);
+ 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) {
// Determine which phi node operands need copies
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)
- if (!I->empty() &&
- I->begin()->getOpcode() == TargetInstrInfo::PHI)
+ if (!I->empty() && I->begin()->isPHI())
processBlock(I);
// Break interferences where two different phis want to coalesce
unsigned reg = OI->first;
++OI;
I->second.erase(reg);
- DOUT << "Removing Renaming: " << reg << " -> " << I->first << "\n";
+ DEBUG(dbgs() << "Removing Renaming: " << reg << " -> " << I->first
+ << "\n");
}
}
}
while (I->second.size()) {
std::map<unsigned, MachineBasicBlock*>::iterator SI = I->second.begin();
- DOUT << "Renaming: " << SI->first << " -> " << I->first << "\n";
+ DEBUG(dbgs() << "Renaming: " << SI->first << " -> " << I->first << "\n");
if (SI->first != I->first) {
- mergeLiveIntervals(I->first, SI->first);
- Fn.getRegInfo().replaceRegWith(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);
+ if (RenameSets.count(SI->first)) {
+ I->second.insert(RenameSets[SI->first].begin(),
+ RenameSets[SI->first].end());
+ RenameSets.erase(SI->first);
+ }
+ } else {
+ // Insert a last-minute copy if a conflict was detected.
+ const TargetInstrInfo *TII = Fn.getTarget().getInstrInfo();
+ BuildMI(*SI->second, SI->second->getFirstTerminator(), DebugLoc(),
+ TII->get(TargetOpcode::COPY), I->first).addReg(SI->first);
+
+ 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);
}
- // FIXME: Insert last-minute copies
-
// Remove PHIs
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->getOpcode() == TargetInstrInfo::PHI)
+ if (BI->isPHI())
phis.push_back(BI);
}
if (PI.containsOneValue()) {
LI.removeInterval(DestReg);
} else {
- unsigned idx = LI.getDefIndex(LI.getInstructionIndex(PInstr));
+ SlotIndex idx = LI.getInstructionIndex(PInstr).getDefIndex();
PI.removeRange(*PI.getLiveRangeContaining(idx), true);
}
} else {
LiveInterval& InputI = LI.getInterval(reg);
if (MBB != PInstr->getParent() &&
InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())) &&
- InputI.expiredAt(LI.getInstructionIndex(PInstr) +
- LiveIntervals::InstrSlots::NUM))
+ InputI.expiredAt(LI.getInstructionIndex(PInstr).getNextIndex()))
InputI.removeRange(LI.getMBBStartIdx(PInstr->getParent()),
LI.getInstructionIndex(PInstr),
true);
// If the PHI is not dead, then the valno defined by the PHI
// now has an unknown def.
- unsigned idx = LI.getDefIndex(LI.getInstructionIndex(PInstr));
+ SlotIndex idx = LI.getInstructionIndex(PInstr).getDefIndex();
const LiveRange* PLR = PI.getLiveRangeContaining(idx);
- PLR->valno->def = ~0U;
+ PLR->valno->setIsPHIDef(true);
LiveRange R (LI.getMBBStartIdx(PInstr->getParent()),
PLR->start, PLR->valno);
PI.addRange(R);
PInstr->eraseFromParent();
}
- LI.computeNumbering();
+ LI.renumber();
return true;
}