assert(N->getParent() != 0 && "machine instruction not in a basic block");
// Remove from the use/def lists.
- N->RemoveRegOperandsFromUseLists();
+ if (MachineFunction *MF = N->getParent()->getParent())
+ N->RemoveRegOperandsFromUseLists(MF->getRegInfo());
N->setParent(0);
return 0;
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void MachineBasicBlock::dump() const {
print(dbgs());
}
+#endif
StringRef MachineBasicBlock::getName() const {
if (const BasicBlock *LBB = getBasicBlock())
return "(null)";
}
+/// Return a hopefully unique identifier for this block.
+std::string MachineBasicBlock::getFullName() const {
+ std::string Name;
+ if (getParent())
+ Name = (getParent()->getName() + ":").str();
+ if (getBasicBlock())
+ Name += getBasicBlock()->getName();
+ else
+ Name += (Twine("BB") + Twine(getNumber())).str();
+ return Name;
+}
+
void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const {
const MachineFunction *MF = getParent();
if (!MF) {
}
if (isLandingPad()) { OS << Comma << "EH LANDING PAD"; Comma = ", "; }
if (hasAddressTaken()) { OS << Comma << "ADDRESS TAKEN"; Comma = ", "; }
- if (Alignment) {
+ if (Alignment)
OS << Comma << "Align " << Alignment << " (" << (1u << Alignment)
<< " bytes)";
- Comma = ", ";
- }
OS << '\n';
if (!succ_empty()) {
if (Indexes) OS << '\t';
OS << " Successors according to CFG:";
- for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI)
+ for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI) {
OS << " BB#" << (*SI)->getNumber();
+ if (!Weights.empty())
+ OS << '(' << *getWeightIterator(SI) << ')';
+ }
OS << '\n';
}
}
void MachineBasicBlock::removeLiveIn(unsigned Reg) {
std::vector<unsigned>::iterator I =
std::find(LiveIns.begin(), LiveIns.end(), Reg);
- assert(I != LiveIns.end() && "Not a live in!");
- LiveIns.erase(I);
+ if (I != LiveIns.end())
+ LiveIns.erase(I);
}
bool MachineBasicBlock::isLiveIn(unsigned Reg) const {
TII->InsertBranch(*this, TBB, 0, Cond, dl);
}
} else {
+ // Walk through the successors and find the successor which is not
+ // a landing pad and is not the conditional branch destination (in TBB)
+ // as the fallthrough successor.
+ MachineBasicBlock *FallthroughBB = 0;
+ for (succ_iterator SI = succ_begin(), SE = succ_end(); SI != SE; ++SI) {
+ if ((*SI)->isLandingPad() || *SI == TBB)
+ continue;
+ assert(!FallthroughBB && "Found more than one fallthrough successor.");
+ FallthroughBB = *SI;
+ }
+ if (!FallthroughBB && canFallThrough()) {
+ // We fallthrough to the same basic block as the conditional jump
+ // targets. Remove the conditional jump, leaving unconditional
+ // fallthrough.
+ // FIXME: This does not seem like a reasonable pattern to support, but it
+ // has been seen in the wild coming out of degenerate ARM test cases.
+ TII->RemoveBranch(*this);
+
+ // Finally update the unconditional successor to be reached via a branch
+ // if it would not be reached by fallthrough.
+ if (!isLayoutSuccessor(TBB))
+ TII->InsertBranch(*this, TBB, 0, Cond, dl);
+ return;
+ }
+
// The block has a fallthrough conditional branch.
- MachineBasicBlock *MBBA = *succ_begin();
- MachineBasicBlock *MBBB = *llvm::next(succ_begin());
- if (MBBA == TBB) std::swap(MBBB, MBBA);
if (isLayoutSuccessor(TBB)) {
if (TII->ReverseBranchCondition(Cond)) {
// We can't reverse the condition, add an unconditional branch.
Cond.clear();
- TII->InsertBranch(*this, MBBA, 0, Cond, dl);
+ TII->InsertBranch(*this, FallthroughBB, 0, Cond, dl);
return;
}
TII->RemoveBranch(*this);
- TII->InsertBranch(*this, MBBA, 0, Cond, dl);
- } else if (!isLayoutSuccessor(MBBA)) {
+ TII->InsertBranch(*this, FallthroughBB, 0, Cond, dl);
+ } else if (!isLayoutSuccessor(FallthroughBB)) {
TII->RemoveBranch(*this);
- TII->InsertBranch(*this, TBB, MBBA, Cond, dl);
+ TII->InsertBranch(*this, TBB, FallthroughBB, Cond, dl);
}
}
}
void MachineBasicBlock::replaceSuccessor(MachineBasicBlock *Old,
MachineBasicBlock *New) {
- uint32_t weight = 0;
- succ_iterator SI = std::find(Successors.begin(), Successors.end(), Old);
+ if (Old == New)
+ return;
- // If Weight list is empty it means we don't use it (disabled optimization).
- if (!Weights.empty()) {
- weight_iterator WI = getWeightIterator(SI);
- weight = *WI;
+ succ_iterator E = succ_end();
+ succ_iterator NewI = E;
+ succ_iterator OldI = E;
+ for (succ_iterator I = succ_begin(); I != E; ++I) {
+ if (*I == Old) {
+ OldI = I;
+ if (NewI != E)
+ break;
+ }
+ if (*I == New) {
+ NewI = I;
+ if (OldI != E)
+ break;
+ }
}
+ assert(OldI != E && "Old is not a successor of this block");
+ Old->removePredecessor(this);
- // Update the successor information.
- removeSuccessor(SI);
- addSuccessor(New, weight);
+ // If New isn't already a successor, let it take Old's place.
+ if (NewI == E) {
+ New->addPredecessor(this);
+ *OldI = New;
+ return;
+ }
+
+ // New is already a successor.
+ // Update its weight instead of adding a duplicate edge.
+ if (!Weights.empty()) {
+ weight_iterator OldWI = getWeightIterator(OldI);
+ *getWeightIterator(NewI) += *OldWI;
+ Weights.erase(OldWI);
+ }
+ Successors.erase(OldI);
}
void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) {
while (!fromMBB->succ_empty()) {
MachineBasicBlock *Succ = *fromMBB->succ_begin();
- uint32_t weight = 0;
-
+ uint32_t Weight = 0;
// If Weight list is empty it means we don't use it (disabled optimization).
if (!fromMBB->Weights.empty())
- weight = *fromMBB->Weights.begin();
+ Weight = *fromMBB->Weights.begin();
- addSuccessor(Succ, weight);
+ addSuccessor(Succ, Weight);
fromMBB->removeSuccessor(Succ);
}
}
while (!fromMBB->succ_empty()) {
MachineBasicBlock *Succ = *fromMBB->succ_begin();
- addSuccessor(Succ);
+ uint32_t Weight = 0;
+ if (!fromMBB->Weights.empty())
+ Weight = *fromMBB->Weights.begin();
+ addSuccessor(Succ, Weight);
fromMBB->removeSuccessor(Succ);
// Fix up any PHI nodes in the successor.
}
}
+bool MachineBasicBlock::isPredecessor(const MachineBasicBlock *MBB) const {
+ return std::find(pred_begin(), pred_end(), MBB) != pred_end();
+}
+
bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const {
- const_succ_iterator I = std::find(Successors.begin(), Successors.end(), MBB);
- return I != Successors.end();
+ return std::find(succ_begin(), succ_end(), MBB) != succ_end();
}
bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
MachineBasicBlock *
MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
+ // Splitting the critical edge to a landing pad block is non-trivial. Don't do
+ // it in this generic function.
+ if (Succ->isLandingPad())
+ return NULL;
+
MachineFunction *MF = getParent();
DebugLoc dl; // FIXME: this is nowhere
// Inherit live-ins from the successor
for (MachineBasicBlock::livein_iterator I = Succ->livein_begin(),
- E = Succ->livein_end(); I != E; ++I)
+ E = Succ->livein_end(); I != E; ++I)
NMBB->addLiveIn(*I);
// Update LiveVariables.
/// getSuccWeight - Return weight of the edge from this block to MBB.
///
-uint32_t MachineBasicBlock::getSuccWeight(const MachineBasicBlock *succ) const {
+uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const {
if (Weights.empty())
return 0;
- const_succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
- return *getWeightIterator(I);
+ return *getWeightIterator(Succ);
}
/// getWeightIterator - Return wight iterator corresonding to the I successor
return Weights.begin() + index;
}
+/// Return whether (physical) register "Reg" has been <def>ined and not <kill>ed
+/// as of just before "MI".
+///
+/// Search is localised to a neighborhood of
+/// Neighborhood instructions before (searching for defs or kills) and N
+/// instructions after (searching just for defs) MI.
+MachineBasicBlock::LivenessQueryResult
+MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI,
+ unsigned Reg, MachineInstr *MI,
+ unsigned Neighborhood) {
+
+ unsigned N = Neighborhood;
+ MachineBasicBlock *MBB = MI->getParent();
+
+ // Start by searching backwards from MI, looking for kills, reads or defs.
+
+ MachineBasicBlock::iterator I(MI);
+ // If this is the first insn in the block, don't search backwards.
+ if (I != MBB->begin()) {
+ do {
+ --I;
+
+ MachineOperandIteratorBase::PhysRegInfo Analysis =
+ MIOperands(I).analyzePhysReg(Reg, TRI);
+
+ if (Analysis.Kills)
+ // Register killed, so isn't live.
+ return LQR_Dead;
+
+ else if (Analysis.DefinesOverlap || Analysis.ReadsOverlap)
+ // Defined or read without a previous kill - live.
+ return (Analysis.Defines || Analysis.Reads) ?
+ LQR_Live : LQR_OverlappingLive;
+
+ } while (I != MBB->begin() && --N > 0);
+ }
+
+ // Did we get to the start of the block?
+ if (I == MBB->begin()) {
+ // If so, the register's state is definitely defined by the live-in state.
+ for (MCRegAliasIterator RAI(Reg, TRI, /*IncludeSelf=*/true);
+ RAI.isValid(); ++RAI) {
+ if (MBB->isLiveIn(*RAI))
+ return (*RAI == Reg) ? LQR_Live : LQR_OverlappingLive;
+ }
+
+ return LQR_Dead;
+ }
+
+ N = Neighborhood;
+
+ // Try searching forwards from MI, looking for reads or defs.
+ I = MachineBasicBlock::iterator(MI);
+ // If this is the last insn in the block, don't search forwards.
+ if (I != MBB->end()) {
+ for (++I; I != MBB->end() && N > 0; ++I, --N) {
+ MachineOperandIteratorBase::PhysRegInfo Analysis =
+ MIOperands(I).analyzePhysReg(Reg, TRI);
+
+ if (Analysis.ReadsOverlap)
+ // Used, therefore must have been live.
+ return (Analysis.Reads) ?
+ LQR_Live : LQR_OverlappingLive;
+
+ else if (Analysis.DefinesOverlap)
+ // Defined (but not read) therefore cannot have been live.
+ return LQR_Dead;
+ }
+ }
+
+ // At this point we have no idea of the liveness of the register.
+ return LQR_Unknown;
+}
+
void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
bool t) {
OS << "BB#" << MBB->getNumber();
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