SmallVectorImpl<MachineOperand> &Cond,
SmallSet<unsigned, 4> &Redefs,
bool IgnoreBr = false);
- void MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI);
+ void MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges = true);
- bool MeetIfcvtSizeLimit(unsigned Size) const {
- return Size > 0 && Size <= TLI->getIfCvtBlockSizeLimit();
+ bool MeetIfcvtSizeLimit(MachineBasicBlock &BB, unsigned Size) const {
+ return Size > 0 && TII->isProfitableToIfCvt(BB, Size);
+ }
+
+ bool MeetIfcvtSizeLimit(MachineBasicBlock &TBB, unsigned TSize,
+ MachineBasicBlock &FBB, unsigned FSize) const {
+ return TSize > 0 && FSize > 0 &&
+ TII->isProfitableToIfCvt(TBB, TSize, FBB, FSize);
}
// blockAlwaysFallThrough - Block ends without a terminator.
TRI = MF.getTarget().getRegisterInfo();
if (!TII) return false;
+ // Tail merge tend to expose more if-conversion opportunities.
+ BranchFolder BF(true);
+ bool BFChange = BF.OptimizeFunction(MF, TII,
+ MF.getTarget().getRegisterInfo(),
+ getAnalysisIfAvailable<MachineModuleInfo>());
+
DEBUG(dbgs() << "\nIfcvt: function (" << ++FnNum << ") \'"
<< MF.getFunction()->getName() << "\'");
RetVal = IfConvertSimple(BBI, Kind);
DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
if (RetVal) {
- if (isFalse) NumSimpleFalse++;
- else NumSimple++;
+ if (isFalse) ++NumSimpleFalse;
+ else ++NumSimple;
}
break;
}
DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
if (RetVal) {
if (isFalse) {
- if (isRev) NumTriangleFRev++;
- else NumTriangleFalse++;
+ if (isRev) ++NumTriangleFRev;
+ else ++NumTriangleFalse;
} else {
- if (isRev) NumTriangleRev++;
- else NumTriangle++;
+ if (isRev) ++NumTriangleRev;
+ else ++NumTriangle;
}
}
break;
<< BBI.FalseBB->getNumber() << ") ");
RetVal = IfConvertDiamond(BBI, Kind, NumDups, NumDups2);
DEBUG(dbgs() << (RetVal ? "succeeded!" : "failed!") << "\n");
- if (RetVal) NumDiamonds++;
+ if (RetVal) ++NumDiamonds;
break;
}
}
Roots.clear();
BBAnalysis.clear();
- if (MadeChange && !IfCvtBranchFold) {
+ if (MadeChange && IfCvtBranchFold) {
BranchFolder BF(false);
BF.OptimizeFunction(MF, TII,
MF.getTarget().getRegisterInfo(),
getAnalysisIfAvailable<MachineModuleInfo>());
}
+ MadeChange |= BFChange;
return MadeChange;
}
/// ReverseBranchCondition - Reverse the condition of the end of the block
/// branch. Swap block's 'true' and 'false' successors.
bool IfConverter::ReverseBranchCondition(BBInfo &BBI) {
+ DebugLoc dl; // FIXME: this is nowhere
if (!TII->ReverseBranchCondition(BBI.BrCond)) {
TII->RemoveBranch(*BBI.BB);
- TII->InsertBranch(*BBI.BB, BBI.FalseBB, BBI.TrueBB, BBI.BrCond);
+ TII->InsertBranch(*BBI.BB, BBI.FalseBB, BBI.TrueBB, BBI.BrCond, dl);
std::swap(BBI.TrueBB, BBI.FalseBB);
return true;
}
if (TrueBBI.BB->pred_size() > 1) {
if (TrueBBI.CannotBeCopied ||
- TrueBBI.NonPredSize > TLI->getIfCvtDupBlockSizeLimit())
+ !TII->isProfitableToDupForIfCvt(*TrueBBI.BB, TrueBBI.NonPredSize))
return false;
Dups = TrueBBI.NonPredSize;
}
++Size;
}
}
- if (Size > TLI->getIfCvtDupBlockSizeLimit())
+ if (!TII->isProfitableToDupForIfCvt(*TrueBBI.BB, Size))
return false;
Dups = Size;
}
while (FI != FIE && FI->isDebugValue())
++FI;
while (TI != TIE && FI != FIE) {
+ // Skip dbg_value instructions. These do not count.
+ if (TI->isDebugValue()) {
+ while (TI != TIE && TI->isDebugValue())
+ ++TI;
+ if (TI == TIE)
+ break;
+ }
+ if (FI->isDebugValue()) {
+ while (FI != FIE && FI->isDebugValue())
+ ++FI;
+ if (FI == FIE)
+ break;
+ }
if (!TI->isIdenticalTo(FI))
break;
++Dups1;
FI = firstNonBranchInst(FalseBBI.BB, TII);
MachineBasicBlock::iterator TIB = TrueBBI.BB->begin();
MachineBasicBlock::iterator FIB = FalseBBI.BB->begin();
- // Skip dbg_value instructions
+ // Skip dbg_value instructions at end of the bb's.
while (TI != TIB && TI->isDebugValue())
--TI;
while (FI != FIB && FI->isDebugValue())
--FI;
while (TI != TIB && FI != FIB) {
+ // Skip dbg_value instructions. These do not count.
+ if (TI->isDebugValue()) {
+ while (TI != TIB && TI->isDebugValue())
+ --TI;
+ if (TI == TIB)
+ break;
+ }
+ if (FI->isDebugValue()) {
+ while (FI != FIB && FI->isDebugValue())
+ --FI;
+ if (FI == FIB)
+ break;
+ }
if (!TI->isIdenticalTo(FI))
break;
++Dups2;
bool FNeedSub = FalseBBI.Predicate.size() > 0;
bool Enqueued = false;
if (CanRevCond && ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2) &&
- MeetIfcvtSizeLimit(TrueBBI.NonPredSize - (Dups + Dups2)) &&
- MeetIfcvtSizeLimit(FalseBBI.NonPredSize - (Dups + Dups2)) &&
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize - (Dups + Dups2),
+ *FalseBBI.BB, FalseBBI.NonPredSize - (Dups + Dups2)) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
// Diamond:
}
if (ValidTriangle(TrueBBI, FalseBBI, false, Dups) &&
- MeetIfcvtSizeLimit(TrueBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true)) {
// Triangle:
// EBB
}
if (ValidTriangle(TrueBBI, FalseBBI, true, Dups) &&
- MeetIfcvtSizeLimit(TrueBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleRev, TNeedSub, Dups));
Enqueued = true;
}
if (ValidSimple(TrueBBI, Dups) &&
- MeetIfcvtSizeLimit(TrueBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond)) {
// Simple (split, no rejoin):
// EBB
if (CanRevCond) {
// Try the other path...
if (ValidTriangle(FalseBBI, TrueBBI, false, Dups) &&
- MeetIfcvtSizeLimit(FalseBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize) &&
FeasibilityAnalysis(FalseBBI, RevCond, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFalse, FNeedSub, Dups));
Enqueued = true;
}
if (ValidTriangle(FalseBBI, TrueBBI, true, Dups) &&
- MeetIfcvtSizeLimit(FalseBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize) &&
FeasibilityAnalysis(FalseBBI, RevCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFRev, FNeedSub, Dups));
Enqueued = true;
}
if (ValidSimple(FalseBBI, Dups) &&
- MeetIfcvtSizeLimit(FalseBBI.NonPredSize) &&
+ MeetIfcvtSizeLimit(*FalseBBI.BB, FalseBBI.NonPredSize) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
Tokens.push_back(new IfcvtToken(BBI, ICSimpleFalse, FNeedSub, Dups));
Enqueued = true;
///
static void InsertUncondBranch(MachineBasicBlock *BB, MachineBasicBlock *ToBB,
const TargetInstrInfo *TII) {
+ DebugLoc dl; // FIXME: this is nowhere
SmallVector<MachineOperand, 0> NoCond;
- TII->InsertBranch(*BB, ToBB, NULL, NoCond);
+ TII->InsertBranch(*BB, ToBB, NULL, NoCond, dl);
}
/// RemoveExtraEdges - Remove true / false edges if either / both are no longer
if (AddImpUse)
// Treat predicated update as read + write.
MI->addOperand(MachineOperand::CreateReg(Reg, false/*IsDef*/,
- true/*IsImp*/,false/*IsKill*/));
+ true/*IsImp*/,false/*IsKill*/));
} else {
Redefs.insert(Reg);
for (const unsigned *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
if (TII->ReverseBranchCondition(Cond))
assert(false && "Unable to reverse branch condition!");
- // Initialize liveins to the first BB. These are potentiall re-defined by
+ // Initialize liveins to the first BB. These are potentiall redefined by
// predicated instructions.
SmallSet<unsigned, 4> Redefs;
InitPredRedefs(CvtBBI->BB, Redefs, TRI);
BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
BBInfo *CvtBBI = &TrueBBI;
BBInfo *NextBBI = &FalseBBI;
+ DebugLoc dl; // FIXME: this is nowhere
SmallVector<MachineOperand, 4> Cond(BBI.BrCond.begin(), BBI.BrCond.end());
if (Kind == ICTriangleFalse || Kind == ICTriangleFRev)
}
}
- // Initialize liveins to the first BB. These are potentiall re-defined by
+ // Initialize liveins to the first BB. These are potentially redefined by
// predicated instructions.
SmallSet<unsigned, 4> Redefs;
InitPredRedefs(CvtBBI->BB, Redefs, TRI);
InitPredRedefs(NextBBI->BB, Redefs, TRI);
bool HasEarlyExit = CvtBBI->FalseBB != NULL;
- bool DupBB = CvtBBI->BB->pred_size() > 1;
- if (DupBB) {
+ if (CvtBBI->BB->pred_size() > 1) {
BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
// Copy instructions in the true block, predicate them, and add them to
// the entry block.
// Now merge the entry of the triangle with the true block.
BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
- MergeBlocks(BBI, *CvtBBI);
+ MergeBlocks(BBI, *CvtBBI, false);
}
// If 'true' block has a 'false' successor, add an exit branch to it.
CvtBBI->BrCond.end());
if (TII->ReverseBranchCondition(RevCond))
assert(false && "Unable to reverse branch condition!");
- TII->InsertBranch(*BBI.BB, CvtBBI->FalseBB, NULL, RevCond);
+ TII->InsertBranch(*BBI.BB, CvtBBI->FalseBB, NULL, RevCond, dl);
BBI.BB->addSuccessor(CvtBBI->FalseBB);
}
return false;
}
- // Merge the 'true' and 'false' blocks by copying the instructions
- // from the 'false' block to the 'true' block. That is, unless the true
- // block would clobber the predicate, in that case, do the opposite.
+ // Put the predicated instructions from the 'true' block before the
+ // instructions from the 'false' block, unless the true block would clobber
+ // the predicate, in which case, do the opposite.
BBInfo *BBI1 = &TrueBBI;
BBInfo *BBI2 = &FalseBBI;
SmallVector<MachineOperand, 4> RevCond(BBI.BrCond.begin(), BBI.BrCond.end());
// Remove the conditional branch from entry to the blocks.
BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
- // Initialize liveins to the first BB. These are potentiall re-defined by
+ // Initialize liveins to the first BB. These are potentially redefined by
// predicated instructions.
SmallSet<unsigned, 4> Redefs;
InitPredRedefs(BBI1->BB, Redefs, TRI);
++DI2;
BBI1->NonPredSize -= NumDups1;
BBI2->NonPredSize -= NumDups1;
+
+ // Skip past the dups on each side separately since there may be
+ // differing dbg_value entries.
+ for (unsigned i = 0; i < NumDups1; ++DI1) {
+ if (!DI1->isDebugValue())
+ ++i;
+ }
while (NumDups1 != 0) {
- ++DI1;
++DI2;
- --NumDups1;
+ if (!DI2->isDebugValue())
+ --NumDups1;
}
UpdatePredRedefs(BBI1->BB->begin(), DI1, Redefs, TRI);
PredicateBlock(*BBI2, DI2, *Cond2, Redefs);
// Merge the true block into the entry of the diamond.
- MergeBlocks(BBI, *BBI1);
- MergeBlocks(BBI, *BBI2);
+ MergeBlocks(BBI, *BBI1, TailBB == 0);
+ MergeBlocks(BBI, *BBI2, TailBB == 0);
// If the if-converted block falls through or unconditionally branches into
// the tail block, and the tail block does not have other predecessors, then
// tail, add a unconditional branch to it.
if (TailBB) {
BBInfo TailBBI = BBAnalysis[TailBB->getNumber()];
- if (TailBB->pred_size() == 1 && !TailBBI.HasFallThrough) {
- BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
+ bool CanMergeTail = !TailBBI.HasFallThrough;
+ // There may still be a fall-through edge from BBI1 or BBI2 to TailBB;
+ // check if there are any other predecessors besides those.
+ unsigned NumPreds = TailBB->pred_size();
+ if (NumPreds > 1)
+ CanMergeTail = false;
+ else if (NumPreds == 1 && CanMergeTail) {
+ MachineBasicBlock::pred_iterator PI = TailBB->pred_begin();
+ if (*PI != BBI1->BB && *PI != BBI2->BB)
+ CanMergeTail = false;
+ }
+ if (CanMergeTail) {
MergeBlocks(BBI, TailBBI);
TailBBI.IsDone = true;
} else {
+ BBI.BB->addSuccessor(TailBB);
InsertUncondBranch(BBI.BB, TailBB, TII);
BBI.HasFallThrough = false;
}
}
+ // RemoveExtraEdges won't work if the block has an unanalyzable branch,
+ // which can happen here if TailBB is unanalyzable and is merged, so
+ // explicitly remove BBI1 and BBI2 as successors.
+ BBI.BB->removeSuccessor(BBI1->BB);
+ BBI.BB->removeSuccessor(BBI2->BB);
RemoveExtraEdges(BBI);
// Update block info.
llvm_unreachable(0);
}
- // If the predicated instruction now re-defines a register as the result of
+ // If the predicated instruction now redefines a register as the result of
// if-conversion, add an implicit kill.
UpdatePredRedefs(I, Redefs, TRI, true);
}
BBI.IsAnalyzed = false;
BBI.NonPredSize = 0;
- NumIfConvBBs++;
+ ++NumIfConvBBs;
}
/// CopyAndPredicateBlock - Copy and predicate instructions from source BB to
for (MachineBasicBlock::iterator I = FromBBI.BB->begin(),
E = FromBBI.BB->end(); I != E; ++I) {
const TargetInstrDesc &TID = I->getDesc();
- bool isPredicated = TII->isPredicated(I);
// Do not copy the end of the block branches.
- if (IgnoreBr && !isPredicated && TID.isBranch())
+ if (IgnoreBr && TID.isBranch())
break;
MachineInstr *MI = MF.CloneMachineInstr(I);
ToBBI.BB->insert(ToBBI.BB->end(), MI);
ToBBI.NonPredSize++;
- if (!isPredicated && !MI->isDebugValue()) {
+ if (!TII->isPredicated(I) && !MI->isDebugValue()) {
if (!TII->PredicateInstruction(MI, Cond)) {
#ifndef NDEBUG
dbgs() << "Unable to predicate " << *I << "!\n";
}
}
- // If the predicated instruction now re-defines a register as the result of
+ // If the predicated instruction now redefines a register as the result of
// if-conversion, add an implicit kill.
UpdatePredRedefs(MI, Redefs, TRI, true);
}
- std::vector<MachineBasicBlock *> Succs(FromBBI.BB->succ_begin(),
- FromBBI.BB->succ_end());
- MachineBasicBlock *NBB = getNextBlock(FromBBI.BB);
- MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : NULL;
+ if (!IgnoreBr) {
+ std::vector<MachineBasicBlock *> Succs(FromBBI.BB->succ_begin(),
+ FromBBI.BB->succ_end());
+ MachineBasicBlock *NBB = getNextBlock(FromBBI.BB);
+ MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : NULL;
- for (unsigned i = 0, e = Succs.size(); i != e; ++i) {
- MachineBasicBlock *Succ = Succs[i];
- // Fallthrough edge can't be transferred.
- if (Succ == FallThrough)
- continue;
- ToBBI.BB->addSuccessor(Succ);
+ for (unsigned i = 0, e = Succs.size(); i != e; ++i) {
+ MachineBasicBlock *Succ = Succs[i];
+ // Fallthrough edge can't be transferred.
+ if (Succ == FallThrough)
+ continue;
+ ToBBI.BB->addSuccessor(Succ);
+ }
}
std::copy(FromBBI.Predicate.begin(), FromBBI.Predicate.end(),
ToBBI.ClobbersPred |= FromBBI.ClobbersPred;
ToBBI.IsAnalyzed = false;
- NumDupBBs++;
+ ++NumDupBBs;
}
/// MergeBlocks - Move all instructions from FromBB to the end of ToBB.
-///
-void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI) {
+/// This will leave FromBB as an empty block, so remove all of its
+/// successor edges except for the fall-through edge. If AddEdges is true,
+/// i.e., when FromBBI's branch is being moved, add those successor edges to
+/// ToBBI.
+void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) {
ToBBI.BB->splice(ToBBI.BB->end(),
FromBBI.BB, FromBBI.BB->begin(), FromBBI.BB->end());
- // Redirect all branches to FromBB to ToBB.
- std::vector<MachineBasicBlock *> Preds(FromBBI.BB->pred_begin(),
- FromBBI.BB->pred_end());
- for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
- MachineBasicBlock *Pred = Preds[i];
- if (Pred == ToBBI.BB)
- continue;
- Pred->ReplaceUsesOfBlockWith(FromBBI.BB, ToBBI.BB);
- }
-
std::vector<MachineBasicBlock *> Succs(FromBBI.BB->succ_begin(),
FromBBI.BB->succ_end());
MachineBasicBlock *NBB = getNextBlock(FromBBI.BB);
if (Succ == FallThrough)
continue;
FromBBI.BB->removeSuccessor(Succ);
- ToBBI.BB->addSuccessor(Succ);
+ if (AddEdges)
+ ToBBI.BB->addSuccessor(Succ);
}
// Now FromBBI always falls through to the next block!
projects / oota-llvm.git / blobdiff