#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 {
static char ID; // Pass identification, replacement for typeid
- StrongPHIElimination() : MachineFunctionPass((intptr_t)&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;
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);
};
}
LiveIntervals& LI) {
LiveInterval& I = LI.getOrCreateInterval(r);
unsigned idx = LI.getMBBStartIdx(MBB);
- return I.liveBeforeAndAt(idx);
+ return I.liveAt(idx);
}
/// isLiveOut - help method that determines, from a regno, if a register is
MachineBasicBlock::iterator P = MBB->begin();
while (P != MBB->end() && P->getOpcode() == TargetInstrInfo::PHI) {
unsigned DestReg = P->getOperand(0).getReg();
-
// Don't both doing PHI elimination for dead PHI's.
if (P->registerDefIsDead(DestReg)) {
ProcessedNames.insert(SrcReg);
continue;
}
+
+ // We don't need to insert copies for implicit_defs.
+ MachineInstr* DefMI = MRI.getVRegDef(SrcReg);
+ if (DefMI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF)
+ ProcessedNames.insert(SrcReg);
// Check for trivial interferences via liveness information, allowing us
// to avoid extra work later. Any registers that interfere cannot both
}
// 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";
+ }
+
RenameSets.insert(std::make_pair(P->getOperand(0).getReg(), PHIUnion));
// Remember which registers are already renamed, so that we don't try to
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);
TII->copyRegToReg(*PI->getParent(), PI, t,
curr.second, RC, RC);
+ DOUT << "Inserted copy from " << curr.second << " to " << t << "\n";
+
// Push temporary on Stacks
Stacks[curr.second].push_back(t);
TII->copyRegToReg(*MBB, MBB->getFirstTerminator(), curr.second,
map[curr.first], RC, RC);
map[curr.first] = curr.second;
+ DOUT << "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();
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 &&
- !LI.getOrCreateInterval(I->first).liveAt(
- LI.getMBBEndIdx(I->second->getParent())))
- LI.addLiveRangeToEndOfBlock(I->first, I->second);
+ 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,
+ true);
+
+ LiveRange R = LI.addLiveRangeToEndOfBlock(I->first, I->second);
+ R.valno->copy = I->second;
+ R.valno->def =
+ LiveIntervals::getDefIndex(LI.getInstructionIndex(I->second));
+ }
}
}
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());
LiveIntervals::getUseIndex(LI.getInstructionIndex(I)));
LiveRange LR (LI.getMBBStartIdx(I->getParent()),
- LiveIntervals::getUseIndex(LI.getInstructionIndex(I)),
+ LiveIntervals::getUseIndex(LI.getInstructionIndex(I))+1,
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& RHS = LI.getOrCreateInterval(secondary);
LI.computeNumbering();
-
- SmallVector<VNInfo*, 4> VNSet (RHS.vni_begin(), RHS.vni_end());
+
DenseMap<VNInfo*, VNInfo*> VNMap;
- for (SmallVector<VNInfo*, 4>::iterator VI = VNSet.begin(),
- VE = VNSet.end(); VI != VE; ++VI) {
- VNInfo* NewVN = LHS.getNextValue((*VI)->def,
- (*VI)->copy,
- LI.getVNInfoAllocator());
- LHS.MergeValueInAsValue(RHS, *VI, NewVN);
- RHS.removeValNo(*VI);
+ 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.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;
}
- if (RHS.empty())
- LI.removeInterval(RHS.reg);
+ 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.getNextValue(OldVN->def,
+ OldVN->copy,
+ LI.getVNInfoAllocator());
+ NewVN->kills = OldVN->kills;
+ }
+
+ LiveRange LR (R.start, R.end, NewVN);
+ LHS.addRange(LR);
+ }
+
+ LI.removeInterval(RHS.reg);
+
+ return true;
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
unsigned reg = OI->first;
++OI;
I->second.erase(reg);
+ DOUT << "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";
+
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();
+ const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(I->first);
+ TII->copyRegToReg(*SI->second, SI->second->getFirstTerminator(),
+ I->first, SI->first, RC, RC);
+
+ LI.computeNumbering();
+
+ LiveInterval& Int = LI.getOrCreateInterval(I->first);
+ unsigned instrIdx =
+ LI.getInstructionIndex(--SI->second->getFirstTerminator());
+ if (Int.liveAt(LiveIntervals::getDefIndex(instrIdx)))
+ Int.removeRange(LiveIntervals::getDefIndex(instrIdx),
+ LI.getMBBEndIdx(SI->second)+1, true);
+
+ LiveRange R = LI.addLiveRangeToEndOfBlock(I->first,
+ --SI->second->getFirstTerminator());
+ R.valno->copy = --SI->second->getFirstTerminator();
+ R.valno->def = LiveIntervals::getDefIndex(instrIdx);
+
+ DOUT << "Renaming failed: " << SI->first << " -> "
+ << I->first << "\n";
}
}
+ LiveInterval& Int = LI.getOrCreateInterval(I->first);
+ const LiveRange* LR =
+ Int.getLiveRangeContaining(LI.getMBBEndIdx(SI->second));
+ LR->valno->hasPHIKill = 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) {
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