#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
/// ClobbersPred - True if BB could modify predicates (e.g. has
/// cmp, call, etc.)
/// NonPredSize - Number of non-predicated instructions.
- /// ExtraCost - Extra cost for microcoded instructions.
+ /// ExtraCost - Extra cost for multi-cycle instructions.
+ /// ExtraCost2 - Some instructions are slower when predicated
/// BB - Corresponding MachineBasicBlock.
/// TrueBB / FalseBB- See AnalyzeBranch().
/// BrCond - Conditions for end of block conditional branches.
bool ClobbersPred : 1;
unsigned NonPredSize;
unsigned ExtraCost;
+ unsigned ExtraCost2;
MachineBasicBlock *BB;
MachineBasicBlock *TrueBB;
MachineBasicBlock *FalseBB;
IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false),
HasFallThrough(false), IsUnpredicable(false),
CannotBeCopied(false), ClobbersPred(false), NonPredSize(0),
- ExtraCost(0), BB(0), TrueBB(0), FalseBB(0) {}
+ ExtraCost(0), ExtraCost2(0), BB(0), TrueBB(0), FalseBB(0) {}
};
/// IfcvtToken - Record information about pending if-conversions to attempt:
: BBI(b), Kind(k), NeedSubsumption(s), NumDups(d), NumDups2(d2) {}
};
- /// Roots - Basic blocks that do not have successors. These are the starting
- /// points of Graph traversal.
- std::vector<MachineBasicBlock*> Roots;
-
/// BBAnalysis - Results of if-conversion feasibility analysis indexed by
/// basic block number.
std::vector<BBInfo> BBAnalysis;
bool IgnoreBr = false);
void MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges = true);
- bool MeetIfcvtSizeLimit(MachineBasicBlock &BB, unsigned Size,
+ bool MeetIfcvtSizeLimit(MachineBasicBlock &BB,
+ unsigned Cycle, unsigned Extra,
float Prediction, float Confidence) const {
- return Size > 0 && TII->isProfitableToIfCvt(BB, Size,
- Prediction, Confidence);
+ return Cycle > 0 && TII->isProfitableToIfCvt(BB, Cycle, Extra,
+ Prediction, Confidence);
}
- bool MeetIfcvtSizeLimit(MachineBasicBlock &TBB, unsigned TSize,
- MachineBasicBlock &FBB, unsigned FSize,
+ bool MeetIfcvtSizeLimit(MachineBasicBlock &TBB,
+ unsigned TCycle, unsigned TExtra,
+ MachineBasicBlock &FBB,
+ unsigned FCycle, unsigned FExtra,
float Prediction, float Confidence) const {
- return TSize > 0 && FSize > 0 &&
- TII->isProfitableToIfCvt(TBB, TSize, FBB, FSize,
+ return TCycle > 0 && FCycle > 0 &&
+ TII->isProfitableToIfCvt(TBB, TCycle, TExtra, FBB, FCycle, FExtra,
Prediction, Confidence);
}
if (!TII) return false;
// Tail merge tend to expose more if-conversion opportunities.
- BranchFolder BF(true);
+ BranchFolder BF(true, false);
bool BFChange = BF.OptimizeFunction(MF, TII,
MF.getTarget().getRegisterInfo(),
getAnalysisIfAvailable<MachineModuleInfo>());
MF.RenumberBlocks();
BBAnalysis.resize(MF.getNumBlockIDs());
- // Look for root nodes, i.e. blocks without successors.
- for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I)
- if (I->succ_empty())
- Roots.push_back(I);
-
std::vector<IfcvtToken*> Tokens;
MadeChange = false;
unsigned NumIfCvts = NumSimple + NumSimpleFalse + NumTriangle +
}
Tokens.clear();
- Roots.clear();
BBAnalysis.clear();
if (MadeChange && IfCvtBranchFold) {
- BranchFolder BF(false);
+ BranchFolder BF(false, false);
BF.OptimizeFunction(MF, TII,
MF.getTarget().getRegisterInfo(),
getAnalysisIfAvailable<MachineModuleInfo>());
return TExit && TExit == FalseBBI.BB;
}
-static
-MachineBasicBlock::iterator firstNonBranchInst(MachineBasicBlock *BB,
- const TargetInstrInfo *TII) {
- MachineBasicBlock::iterator I = BB->end();
- while (I != BB->begin()) {
- --I;
- if (!I->getDesc().isBranch())
- break;
- }
- return I;
-}
-
/// ValidDiamond - Returns true if the 'true' and 'false' blocks (along
/// with their common predecessor) forms a valid diamond shape for ifcvt.
bool IfConverter::ValidDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI,
(TrueBBI.ClobbersPred && FalseBBI.ClobbersPred))
return false;
- MachineBasicBlock::iterator TI = TrueBBI.BB->begin();
- MachineBasicBlock::iterator FI = FalseBBI.BB->begin();
+ // Count duplicate instructions at the beginning of the true and false blocks.
+ MachineBasicBlock::iterator TIB = TrueBBI.BB->begin();
+ MachineBasicBlock::iterator FIB = FalseBBI.BB->begin();
MachineBasicBlock::iterator TIE = TrueBBI.BB->end();
MachineBasicBlock::iterator FIE = FalseBBI.BB->end();
- // Skip dbg_value instructions
- while (TI != TIE && TI->isDebugValue())
- ++TI;
- while (FI != FIE && FI->isDebugValue())
- ++FI;
- while (TI != TIE && FI != FIE) {
+ while (TIB != TIE && FIB != FIE) {
// Skip dbg_value instructions. These do not count.
- if (TI->isDebugValue()) {
- while (TI != TIE && TI->isDebugValue())
- ++TI;
- if (TI == TIE)
+ if (TIB->isDebugValue()) {
+ while (TIB != TIE && TIB->isDebugValue())
+ ++TIB;
+ if (TIB == TIE)
break;
}
- if (FI->isDebugValue()) {
- while (FI != FIE && FI->isDebugValue())
- ++FI;
- if (FI == FIE)
+ if (FIB->isDebugValue()) {
+ while (FIB != FIE && FIB->isDebugValue())
+ ++FIB;
+ if (FIB == FIE)
break;
}
- if (!TI->isIdenticalTo(FI))
+ if (!TIB->isIdenticalTo(FIB))
break;
++Dups1;
- ++TI;
- ++FI;
+ ++TIB;
+ ++FIB;
}
- TI = firstNonBranchInst(TrueBBI.BB, TII);
- FI = firstNonBranchInst(FalseBBI.BB, TII);
- MachineBasicBlock::iterator TIB = TrueBBI.BB->begin();
- MachineBasicBlock::iterator FIB = FalseBBI.BB->begin();
- // 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) {
+ // Now, in preparation for counting duplicate instructions at the ends of the
+ // blocks, move the end iterators up past any branch instructions.
+ while (TIE != TIB) {
+ --TIE;
+ if (!TIE->getDesc().isBranch())
+ break;
+ }
+ while (FIE != FIB) {
+ --FIE;
+ if (!FIE->getDesc().isBranch())
+ break;
+ }
+
+ // If Dups1 includes all of a block, then don't count duplicate
+ // instructions at the end of the blocks.
+ if (TIB == TIE || FIB == FIE)
+ return true;
+
+ // Count duplicate instructions at the ends of the blocks.
+ while (TIE != TIB && FIE != FIB) {
// Skip dbg_value instructions. These do not count.
- if (TI->isDebugValue()) {
- while (TI != TIB && TI->isDebugValue())
- --TI;
- if (TI == TIB)
+ if (TIE->isDebugValue()) {
+ while (TIE != TIB && TIE->isDebugValue())
+ --TIE;
+ if (TIE == TIB)
break;
}
- if (FI->isDebugValue()) {
- while (FI != FIB && FI->isDebugValue())
- --FI;
- if (FI == FIB)
+ if (FIE->isDebugValue()) {
+ while (FIE != FIB && FIE->isDebugValue())
+ --FIE;
+ if (FIE == FIB)
break;
}
- if (!TI->isIdenticalTo(FI))
+ if (!TIE->isIdenticalTo(FIE))
break;
++Dups2;
- --TI;
- --FI;
+ --TIE;
+ --FIE;
}
return true;
// Then scan all the instructions.
BBI.NonPredSize = 0;
BBI.ExtraCost = 0;
+ BBI.ExtraCost2 = 0;
BBI.ClobbersPred = false;
for (MachineBasicBlock::iterator I = BBI.BB->begin(), E = BBI.BB->end();
I != E; ++I) {
if (!isCondBr) {
if (!isPredicated) {
BBI.NonPredSize++;
- unsigned NumOps = TII->getNumMicroOps(&*I, InstrItins);
- if (NumOps > 1)
- BBI.ExtraCost += NumOps-1;
+ unsigned ExtraPredCost = 0;
+ unsigned NumCycles = TII->getInstrLatency(InstrItins, &*I,
+ &ExtraPredCost);
+ if (NumCycles > 1)
+ BBI.ExtraCost += NumCycles-1;
+ BBI.ExtraCost2 += ExtraPredCost;
} else if (!AlreadyPredicated) {
// FIXME: This instruction is already predicated before the
// if-conversion pass. It's probably something like a conditional move.
if (CanRevCond && ValidDiamond(TrueBBI, FalseBBI, Dups, Dups2) &&
MeetIfcvtSizeLimit(*TrueBBI.BB, (TrueBBI.NonPredSize - (Dups + Dups2) +
- TrueBBI.ExtraCost),
+ TrueBBI.ExtraCost), TrueBBI.ExtraCost2,
*FalseBBI.BB, (FalseBBI.NonPredSize - (Dups + Dups2) +
- FalseBBI.ExtraCost),
+ FalseBBI.ExtraCost),FalseBBI.ExtraCost2,
Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
if (ValidTriangle(TrueBBI, FalseBBI, false, Dups, Prediction, Confidence) &&
MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
- Prediction, Confidence) &&
+ TrueBBI.ExtraCost2, Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true)) {
// Triangle:
// EBB
if (ValidTriangle(TrueBBI, FalseBBI, true, Dups, Prediction, Confidence) &&
MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
- Prediction, Confidence) &&
+ TrueBBI.ExtraCost2, Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleRev, TNeedSub, Dups));
Enqueued = true;
if (ValidSimple(TrueBBI, Dups, Prediction, Confidence) &&
MeetIfcvtSizeLimit(*TrueBBI.BB, TrueBBI.NonPredSize + TrueBBI.ExtraCost,
- Prediction, Confidence) &&
+ TrueBBI.ExtraCost2, Prediction, Confidence) &&
FeasibilityAnalysis(TrueBBI, BBI.BrCond)) {
// Simple (split, no rejoin):
// EBB
1.0-Prediction, Confidence) &&
MeetIfcvtSizeLimit(*FalseBBI.BB,
FalseBBI.NonPredSize + FalseBBI.ExtraCost,
- 1.0-Prediction, Confidence) &&
+ FalseBBI.ExtraCost2, 1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFalse, FNeedSub, Dups));
Enqueued = true;
1.0-Prediction, Confidence) &&
MeetIfcvtSizeLimit(*FalseBBI.BB,
FalseBBI.NonPredSize + FalseBBI.ExtraCost,
- 1.0-Prediction, Confidence) &&
+ FalseBBI.ExtraCost2, 1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond, true, true)) {
Tokens.push_back(new IfcvtToken(BBI, ICTriangleFRev, FNeedSub, Dups));
Enqueued = true;
if (ValidSimple(FalseBBI, Dups, 1.0-Prediction, Confidence) &&
MeetIfcvtSizeLimit(*FalseBBI.BB,
FalseBBI.NonPredSize + FalseBBI.ExtraCost,
- 1.0-Prediction, Confidence) &&
+ FalseBBI.ExtraCost2, 1.0-Prediction, Confidence) &&
FeasibilityAnalysis(FalseBBI, RevCond)) {
Tokens.push_back(new IfcvtToken(BBI, ICSimpleFalse, FNeedSub, Dups));
Enqueued = true;
/// candidates.
void IfConverter::AnalyzeBlocks(MachineFunction &MF,
std::vector<IfcvtToken*> &Tokens) {
- std::set<MachineBasicBlock*> Visited;
- for (unsigned i = 0, e = Roots.size(); i != e; ++i) {
- for (idf_ext_iterator<MachineBasicBlock*> I=idf_ext_begin(Roots[i],Visited),
- E = idf_ext_end(Roots[i], Visited); I != E; ++I) {
- MachineBasicBlock *BB = *I;
- AnalyzeBlock(BB, Tokens);
- }
+ for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
+ MachineBasicBlock *BB = I;
+ AnalyzeBlock(BB, Tokens);
}
// Sort to favor more complex ifcvt scheme.
MachineInstr *MI = MF.CloneMachineInstr(I);
ToBBI.BB->insert(ToBBI.BB->end(), MI);
ToBBI.NonPredSize++;
- unsigned NumOps = TII->getNumMicroOps(MI, InstrItins);
- if (NumOps > 1)
- ToBBI.ExtraCost += NumOps-1;
+ unsigned ExtraPredCost = 0;
+ unsigned NumCycles = TII->getInstrLatency(InstrItins, &*I, &ExtraPredCost);
+ if (NumCycles > 1)
+ ToBBI.ExtraCost += NumCycles-1;
+ ToBBI.ExtraCost2 += ExtraPredCost;
if (!TII->isPredicated(I) && !MI->isDebugValue()) {
if (!TII->PredicateInstruction(MI, Cond)) {
ToBBI.NonPredSize += FromBBI.NonPredSize;
ToBBI.ExtraCost += FromBBI.ExtraCost;
+ ToBBI.ExtraCost2 += FromBBI.ExtraCost2;
FromBBI.NonPredSize = 0;
FromBBI.ExtraCost = 0;
+ FromBBI.ExtraCost2 = 0;
ToBBI.ClobbersPred |= FromBBI.ClobbersPred;
ToBBI.HasFallThrough = FromBBI.HasFallThrough;