X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FIfConversion.cpp;h=1502d5f23efedf106a4567243cafe7120afd9d14;hb=82a35bf01a894b0af8871071df9180c6ab6fe639;hp=c6cef9b114b8f0c0bd44d60dd651ee1b1d187c1d;hpb=57c38e3faa02d660ea09e88c8aa34d6fe1cccb88;p=oota-llvm.git diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp index c6cef9b114b..1502d5f23ef 100644 --- a/lib/CodeGen/IfConversion.cpp +++ b/lib/CodeGen/IfConversion.cpp @@ -11,19 +11,18 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "ifcvt" #include "llvm/CodeGen/Passes.h" #include "BranchFolding.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallSet.h" #include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/LivePhysRegs.h" #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" #include "llvm/CodeGen/MachineFunctionPass.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineModuleInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/TargetSchedule.h" -#include "llvm/CodeGen/LivePhysRegs.h" #include "llvm/MC/MCInstrItineraries.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" @@ -37,6 +36,8 @@ using namespace llvm; +#define DEBUG_TYPE "ifcvt" + // Hidden options for help debugging. static cl::opt IfCvtFnStart("ifcvt-fn-start", cl::init(-1), cl::Hidden); static cl::opt IfCvtFnStop("ifcvt-fn-stop", cl::init(-1), cl::Hidden); @@ -127,7 +128,8 @@ namespace { IsAnalyzed(false), IsEnqueued(false), IsBrAnalyzable(false), HasFallThrough(false), IsUnpredicable(false), CannotBeCopied(false), ClobbersPred(false), NonPredSize(0), - ExtraCost(0), ExtraCost2(0), BB(0), TrueBB(0), FalseBB(0) {} + ExtraCost(0), ExtraCost2(0), BB(nullptr), TrueBB(nullptr), + FalseBB(nullptr) {} }; /// IfcvtToken - Record information about pending if-conversions to attempt: @@ -174,12 +176,12 @@ namespace { initializeIfConverterPass(*PassRegistry::getPassRegistry()); } - virtual void getAnalysisUsage(AnalysisUsage &AU) const { + void getAnalysisUsage(AnalysisUsage &AU) const override { AU.addRequired(); MachineFunctionPass::getAnalysisUsage(AU); } - virtual bool runOnMachineFunction(MachineFunction &MF); + bool runOnMachineFunction(MachineFunction &MF) override; private: bool ReverseBranchCondition(BBInfo &BBI); @@ -205,7 +207,7 @@ namespace { void PredicateBlock(BBInfo &BBI, MachineBasicBlock::iterator E, SmallVectorImpl &Cond, - SmallSet *LaterRedefs = 0); + SmallSet *LaterRedefs = nullptr); void CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI, SmallVectorImpl &Cond, bool IgnoreBr = false); @@ -230,7 +232,7 @@ namespace { // blockAlwaysFallThrough - Block ends without a terminator. bool blockAlwaysFallThrough(BBInfo &BBI) const { - return BBI.IsBrAnalyzable && BBI.TrueBB == NULL; + return BBI.IsBrAnalyzable && BBI.TrueBB == nullptr; } // IfcvtTokenCmp - Used to sort if-conversion candidates. @@ -438,7 +440,7 @@ static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB, if (SuccBB != TrueBB) return SuccBB; } - return NULL; + return nullptr; } /// ReverseBranchCondition - Reverse the condition of the end of the block @@ -460,7 +462,7 @@ static inline MachineBasicBlock *getNextBlock(MachineBasicBlock *BB) { MachineFunction::iterator I = BB; MachineFunction::iterator E = BB->getParent()->end(); if (++I == E) - return NULL; + return nullptr; return I; } @@ -551,7 +553,7 @@ bool IfConverter::ValidDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI, FT = getNextBlock(FalseBBI.BB); if (TT != FT) return false; - if (TT == NULL && (TrueBBI.IsBrAnalyzable || FalseBBI.IsBrAnalyzable)) + if (!TT && (TrueBBI.IsBrAnalyzable || FalseBBI.IsBrAnalyzable)) return false; if (TrueBBI.BB->pred_size() > 1 || FalseBBI.BB->pred_size() > 1) return false; @@ -641,11 +643,11 @@ void IfConverter::ScanInstructions(BBInfo &BBI) { bool AlreadyPredicated = !BBI.Predicate.empty(); // First analyze the end of BB branches. - BBI.TrueBB = BBI.FalseBB = NULL; + BBI.TrueBB = BBI.FalseBB = nullptr; BBI.BrCond.clear(); BBI.IsBrAnalyzable = !TII->AnalyzeBranch(*BBI.BB, BBI.TrueBB, BBI.FalseBB, BBI.BrCond); - BBI.HasFallThrough = BBI.IsBrAnalyzable && BBI.FalseBB == NULL; + BBI.HasFallThrough = BBI.IsBrAnalyzable && BBI.FalseBB == nullptr; if (BBI.BrCond.size()) { // No false branch. This BB must end with a conditional branch and a @@ -921,7 +923,7 @@ void IfConverter::AnalyzeBlocks(MachineFunction &MF, /// next block). static bool canFallThroughTo(MachineBasicBlock *BB, MachineBasicBlock *ToBB) { MachineFunction::iterator PI = BB; - MachineFunction::iterator I = llvm::next(PI); + MachineFunction::iterator I = std::next(PI); MachineFunction::iterator TI = ToBB; MachineFunction::iterator E = BB->getParent()->end(); while (I != TI) { @@ -954,13 +956,13 @@ static void InsertUncondBranch(MachineBasicBlock *BB, MachineBasicBlock *ToBB, const TargetInstrInfo *TII) { DebugLoc dl; // FIXME: this is nowhere SmallVector NoCond; - TII->InsertBranch(*BB, ToBB, NULL, NoCond, dl); + TII->InsertBranch(*BB, ToBB, nullptr, NoCond, dl); } /// RemoveExtraEdges - Remove true / false edges if either / both are no longer /// successors. void IfConverter::RemoveExtraEdges(BBInfo &BBI) { - MachineBasicBlock *TBB = NULL, *FBB = NULL; + MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; if (!TII->AnalyzeBranch(*BBI.BB, TBB, FBB, Cond)) BBI.BB->CorrectExtraCFGEdges(TBB, FBB, !Cond.empty()); @@ -1102,6 +1104,28 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI, IfcvtKind Kind) { return true; } +/// Scale down weights to fit into uint32_t. NewTrue is the new weight +/// for successor TrueBB, and NewFalse is the new weight for successor +/// FalseBB. +static void ScaleWeights(uint64_t NewTrue, uint64_t NewFalse, + MachineBasicBlock *MBB, + const MachineBasicBlock *TrueBB, + const MachineBasicBlock *FalseBB, + const MachineBranchProbabilityInfo *MBPI) { + uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse; + uint32_t Scale = (NewMax / UINT32_MAX) + 1; + for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(), + SE = MBB->succ_end(); + SI != SE; ++SI) { + if (*SI == TrueBB) + MBB->setSuccWeight(SI, (uint32_t)(NewTrue / Scale)); + else if (*SI == FalseBB) + MBB->setSuccWeight(SI, (uint32_t)(NewFalse / Scale)); + else + MBB->setSuccWeight(SI, MBPI->getEdgeWeight(MBB, SI) / Scale); + } +} + /// IfConvertTriangle - If convert a triangle sub-CFG. /// bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { @@ -1157,7 +1181,17 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { DontKill.clear(); - bool HasEarlyExit = CvtBBI->FalseBB != NULL; + bool HasEarlyExit = CvtBBI->FalseBB != nullptr; + uint64_t CvtNext = 0, CvtFalse = 0, BBNext = 0, BBCvt = 0, SumWeight = 0; + uint32_t WeightScale = 0; + if (HasEarlyExit) { + // Get weights before modifying CvtBBI->BB and BBI.BB. + CvtNext = MBPI->getEdgeWeight(CvtBBI->BB, NextBBI->BB); + CvtFalse = MBPI->getEdgeWeight(CvtBBI->BB, CvtBBI->FalseBB); + BBNext = MBPI->getEdgeWeight(BBI.BB, NextBBI->BB); + BBCvt = MBPI->getEdgeWeight(BBI.BB, CvtBBI->BB); + SumWeight = MBPI->getSumForBlock(CvtBBI->BB, WeightScale); + } if (CvtBBI->BB->pred_size() > 1) { BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB); // Copy instructions in the true block, predicate them, and add them to @@ -1183,8 +1217,22 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { CvtBBI->BrCond.end()); if (TII->ReverseBranchCondition(RevCond)) llvm_unreachable("Unable to reverse branch condition!"); - TII->InsertBranch(*BBI.BB, CvtBBI->FalseBB, NULL, RevCond, dl); + TII->InsertBranch(*BBI.BB, CvtBBI->FalseBB, nullptr, RevCond, dl); BBI.BB->addSuccessor(CvtBBI->FalseBB); + // Update the edge weight for both CvtBBI->FalseBB and NextBBI. + // New_Weight(BBI.BB, NextBBI->BB) = + // Weight(BBI.BB, NextBBI->BB) * getSumForBlock(CvtBBI->BB) + + // Weight(BBI.BB, CvtBBI->BB) * Weight(CvtBBI->BB, NextBBI->BB) + // New_Weight(BBI.BB, CvtBBI->FalseBB) = + // Weight(BBI.BB, CvtBBI->BB) * Weight(CvtBBI->BB, CvtBBI->FalseBB) + + uint64_t NewNext = BBNext * SumWeight + (BBCvt * CvtNext) / WeightScale; + uint64_t NewFalse = (BBCvt * CvtFalse) / WeightScale; + // We need to scale down all weights of BBI.BB to fit uint32_t. + // Here BBI.BB is connected to CvtBBI->FalseBB and will fall through to + // the next block. + ScaleWeights(NewNext, NewFalse, BBI.BB, getNextBlock(BBI.BB), + CvtBBI->FalseBB, MBPI); } // Merge in the 'false' block if the 'false' block has no other @@ -1407,8 +1455,8 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI, IfcvtKind Kind, PredicateBlock(*BBI2, DI2, *Cond2); // Merge the true block into the entry of the diamond. - MergeBlocks(BBI, *BBI1, TailBB == 0); - MergeBlocks(BBI, *BBI2, TailBB == 0); + MergeBlocks(BBI, *BBI1, TailBB == nullptr); + MergeBlocks(BBI, *BBI2, TailBB == nullptr); // If the if-converted block falls through or unconditionally branches into // the tail block, and the tail block does not have other predecessors, then @@ -1457,7 +1505,7 @@ static bool MaySpeculate(const MachineInstr *MI, SmallSet &LaterRedefs, const TargetInstrInfo *TII) { bool SawStore = true; - if (!MI->isSafeToMove(TII, 0, SawStore)) + if (!MI->isSafeToMove(TII, nullptr, SawStore)) return false; for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { @@ -1481,7 +1529,7 @@ void IfConverter::PredicateBlock(BBInfo &BBI, SmallVectorImpl &Cond, SmallSet *LaterRedefs) { bool AnyUnpred = false; - bool MaySpec = LaterRedefs != 0; + bool MaySpec = LaterRedefs != nullptr; for (MachineBasicBlock::iterator I = BBI.BB->begin(); I != E; ++I) { if (I->isDebugValue() || TII->isPredicated(I)) continue; @@ -1499,7 +1547,7 @@ void IfConverter::PredicateBlock(BBInfo &BBI, #ifndef NDEBUG dbgs() << "Unable to predicate " << *I << "!\n"; #endif - llvm_unreachable(0); + llvm_unreachable(nullptr); } // If the predicated instruction now redefines a register as the result of @@ -1544,7 +1592,7 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI, #ifndef NDEBUG dbgs() << "Unable to predicate " << *I << "!\n"; #endif - llvm_unreachable(0); + llvm_unreachable(nullptr); } } @@ -1561,7 +1609,7 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI, std::vector Succs(FromBBI.BB->succ_begin(), FromBBI.BB->succ_end()); MachineBasicBlock *NBB = getNextBlock(FromBBI.BB); - MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : NULL; + MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : nullptr; for (unsigned i = 0, e = Succs.size(); i != e; ++i) { MachineBasicBlock *Succ = Succs[i]; @@ -1597,7 +1645,7 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) { std::vector Succs(FromBBI.BB->succ_begin(), FromBBI.BB->succ_end()); MachineBasicBlock *NBB = getNextBlock(FromBBI.BB); - MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : NULL; + MachineBasicBlock *FallThrough = FromBBI.HasFallThrough ? NBB : nullptr; for (unsigned i = 0, e = Succs.size(); i != e; ++i) { MachineBasicBlock *Succ = Succs[i];