diff options
Diffstat (limited to 'lib/Analysis')
| -rw-r--r-- | lib/Analysis/CodeMetrics.cpp | 88 | ||||
| -rw-r--r-- | lib/Analysis/DIBuilder.cpp | 22 | ||||
| -rw-r--r-- | lib/Analysis/DebugInfo.cpp | 18 | ||||
| -rw-r--r-- | lib/Analysis/IPA/GlobalsModRef.cpp | 6 | ||||
| -rw-r--r-- | lib/Analysis/IVUsers.cpp | 27 | ||||
| -rw-r--r-- | lib/Analysis/InlineCost.cpp | 1447 | ||||
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 169 | ||||
| -rw-r--r-- | lib/Analysis/Lint.cpp | 10 | ||||
| -rw-r--r-- | lib/Analysis/LoopInfo.cpp | 11 | ||||
| -rw-r--r-- | lib/Analysis/LoopPass.cpp | 23 | ||||
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 15 | ||||
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 269 |
12 files changed, 1271 insertions, 834 deletions
diff --git a/lib/Analysis/CodeMetrics.cpp b/lib/Analysis/CodeMetrics.cpp index 6c93f78..316e7bc 100644 --- a/lib/Analysis/CodeMetrics.cpp +++ b/lib/Analysis/CodeMetrics.cpp @@ -50,6 +50,52 @@ bool llvm::callIsSmall(const Function *F) { return false; } +bool llvm::isInstructionFree(const Instruction *I, const TargetData *TD) { + if (isa<PHINode>(I)) + return true; + + // If a GEP has all constant indices, it will probably be folded with + // a load/store. + if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) + return GEP->hasAllConstantIndices(); + + if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) { + switch (II->getIntrinsicID()) { + default: + return false; + case Intrinsic::dbg_declare: + case Intrinsic::dbg_value: + case Intrinsic::invariant_start: + case Intrinsic::invariant_end: + case Intrinsic::lifetime_start: + case Intrinsic::lifetime_end: + case Intrinsic::objectsize: + case Intrinsic::ptr_annotation: + case Intrinsic::var_annotation: + // These intrinsics don't count as size. + return true; + } + } + + if (const CastInst *CI = dyn_cast<CastInst>(I)) { + // Noop casts, including ptr <-> int, don't count. + if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || isa<PtrToIntInst>(CI)) + return true; + // trunc to a native type is free (assuming the target has compare and + // shift-right of the same width). + if (TD && isa<TruncInst>(CI) && + TD->isLegalInteger(TD->getTypeSizeInBits(CI->getType()))) + return true; + // Result of a cmp instruction is often extended (to be used by other + // cmp instructions, logical or return instructions). These are usually + // nop on most sane targets. + if (isa<CmpInst>(CI->getOperand(0))) + return true; + } + + return false; +} + /// analyzeBasicBlock - Fill in the current structure with information gleaned /// from the specified block. void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB, @@ -58,27 +104,11 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB, unsigned NumInstsBeforeThisBB = NumInsts; for (BasicBlock::const_iterator II = BB->begin(), E = BB->end(); II != E; ++II) { - if (isa<PHINode>(II)) continue; // PHI nodes don't count. + if (isInstructionFree(II, TD)) + continue; // Special handling for calls. if (isa<CallInst>(II) || isa<InvokeInst>(II)) { - if (const IntrinsicInst *IntrinsicI = dyn_cast<IntrinsicInst>(II)) { - switch (IntrinsicI->getIntrinsicID()) { - default: break; - case Intrinsic::dbg_declare: - case Intrinsic::dbg_value: - case Intrinsic::invariant_start: - case Intrinsic::invariant_end: - case Intrinsic::lifetime_start: - case Intrinsic::lifetime_end: - case Intrinsic::objectsize: - case Intrinsic::ptr_annotation: - case Intrinsic::var_annotation: - // These intrinsics don't count as size. - continue; - } - } - ImmutableCallSite CS(cast<Instruction>(II)); if (const Function *F = CS.getCalledFunction()) { @@ -115,28 +145,6 @@ void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB, if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy()) ++NumVectorInsts; - if (const CastInst *CI = dyn_cast<CastInst>(II)) { - // Noop casts, including ptr <-> int, don't count. - if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) || - isa<PtrToIntInst>(CI)) - continue; - // trunc to a native type is free (assuming the target has compare and - // shift-right of the same width). - if (isa<TruncInst>(CI) && TD && - TD->isLegalInteger(TD->getTypeSizeInBits(CI->getType()))) - continue; - // Result of a cmp instruction is often extended (to be used by other - // cmp instructions, logical or return instructions). These are usually - // nop on most sane targets. - if (isa<CmpInst>(CI->getOperand(0))) - continue; - } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(II)){ - // If a GEP has all constant indices, it will probably be folded with - // a load/store. - if (GEPI->hasAllConstantIndices()) - continue; - } - ++NumInsts; } diff --git a/lib/Analysis/DIBuilder.cpp b/lib/Analysis/DIBuilder.cpp index f0bdc48..85913b1 100644 --- a/lib/Analysis/DIBuilder.cpp +++ b/lib/Analysis/DIBuilder.cpp @@ -17,6 +17,7 @@ #include "llvm/IntrinsicInst.h" #include "llvm/Module.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/Support/Debug.h" #include "llvm/Support/Dwarf.h" using namespace llvm; @@ -385,16 +386,21 @@ DIType DIBuilder::createObjCIVar(StringRef Name, /// createObjCProperty - Create debugging information entry for Objective-C /// property. -DIObjCProperty DIBuilder::createObjCProperty(StringRef Name, +DIObjCProperty DIBuilder::createObjCProperty(StringRef Name, + DIFile File, unsigned LineNumber, StringRef GetterName, StringRef SetterName, - unsigned PropertyAttributes) { + unsigned PropertyAttributes, + DIType Ty) { Value *Elts[] = { - GetTagConstant(VMContext, dwarf::DW_TAG_APPLE_Property), + GetTagConstant(VMContext, dwarf::DW_TAG_APPLE_property), MDString::get(VMContext, Name), + File, + ConstantInt::get(Type::getInt32Ty(VMContext), LineNumber), MDString::get(VMContext, GetterName), MDString::get(VMContext, SetterName), - ConstantInt::get(Type::getInt32Ty(VMContext), PropertyAttributes) + ConstantInt::get(Type::getInt32Ty(VMContext), PropertyAttributes), + Ty }; return DIObjCProperty(MDNode::get(VMContext, Elts)); } @@ -820,6 +826,7 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context, DIFile File, unsigned LineNo, DIType Ty, bool isLocalToUnit, bool isDefinition, + unsigned ScopeLine, unsigned Flags, bool isOptimized, Function *Fn, MDNode *TParams, @@ -849,7 +856,8 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context, Fn, TParams, Decl, - THolder + THolder, + ConstantInt::get(Type::getInt32Ty(VMContext), ScopeLine) }; MDNode *Node = MDNode::get(VMContext, Elts); @@ -897,7 +905,9 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context, Fn, TParam, llvm::Constant::getNullValue(Type::getInt32Ty(VMContext)), - THolder + THolder, + // FIXME: Do we want to use a different scope lines? + ConstantInt::get(Type::getInt32Ty(VMContext), LineNo) }; MDNode *Node = MDNode::get(VMContext, Elts); return DISubprogram(Node); diff --git a/lib/Analysis/DebugInfo.cpp b/lib/Analysis/DebugInfo.cpp index e30c0a9..f61a8f3 100644 --- a/lib/Analysis/DebugInfo.cpp +++ b/lib/Analysis/DebugInfo.cpp @@ -291,7 +291,7 @@ bool DIDescriptor::isEnumerator() const { /// isObjCProperty - Return true if the specified tag is DW_TAG bool DIDescriptor::isObjCProperty() const { - return DbgNode && getTag() == dwarf::DW_TAG_APPLE_Property; + return DbgNode && getTag() == dwarf::DW_TAG_APPLE_property; } //===----------------------------------------------------------------------===// // Simple Descriptor Constructors and other Methods @@ -377,6 +377,19 @@ bool DICompileUnit::Verify() const { return true; } +/// Verify - Verify that an ObjC property is well formed. +bool DIObjCProperty::Verify() const { + if (!DbgNode) + return false; + unsigned Tag = getTag(); + if (Tag != dwarf::DW_TAG_APPLE_property) return false; + DIType Ty = getType(); + if (!Ty.Verify()) return false; + + // Don't worry about the rest of the strings for now. + return true; +} + /// Verify - Verify that a type descriptor is well formed. bool DIType::Verify() const { if (!DbgNode) @@ -774,6 +787,9 @@ void DISubprogram::print(raw_ostream &OS) const { if (isDefinition()) OS << " [def] "; + if (getScopeLineNumber() != getLineNumber()) + OS << " [Scope: " << getScopeLineNumber() << "] "; + OS << "\n"; } diff --git a/lib/Analysis/IPA/GlobalsModRef.cpp b/lib/Analysis/IPA/GlobalsModRef.cpp index b226d66..c1d8e3e 100644 --- a/lib/Analysis/IPA/GlobalsModRef.cpp +++ b/lib/Analysis/IPA/GlobalsModRef.cpp @@ -21,6 +21,7 @@ #include "llvm/Instructions.h" #include "llvm/Constants.h" #include "llvm/DerivedTypes.h" +#include "llvm/IntrinsicInst.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/CallGraph.h" #include "llvm/Analysis/MemoryBuiltins.h" @@ -467,6 +468,11 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) { } else if (isMalloc(&cast<Instruction>(*II)) || isFreeCall(&cast<Instruction>(*II))) { FunctionEffect |= ModRef; + } else if (IntrinsicInst *Intrinsic = dyn_cast<IntrinsicInst>(&*II)) { + // The callgraph doesn't include intrinsic calls. + Function *Callee = Intrinsic->getCalledFunction(); + ModRefBehavior Behaviour = AliasAnalysis::getModRefBehavior(Callee); + FunctionEffect |= (Behaviour & ModRef); } if ((FunctionEffect & Mod) == 0) diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp index 463584d..b80966b 100644 --- a/lib/Analysis/IVUsers.cpp +++ b/lib/Analysis/IVUsers.cpp @@ -107,11 +107,11 @@ static bool isSimplifiedLoopNest(BasicBlock *BB, const DominatorTree *DT, return true; } -/// AddUsersIfInteresting - Inspect the specified instruction. If it is a +/// AddUsersImpl - Inspect the specified instruction. If it is a /// reducible SCEV, recursively add its users to the IVUsesByStride set and /// return true. Otherwise, return false. -bool IVUsers::AddUsersIfInteresting(Instruction *I, - SmallPtrSet<Loop*,16> &SimpleLoopNests) { +bool IVUsers::AddUsersImpl(Instruction *I, + SmallPtrSet<Loop*,16> &SimpleLoopNests) { // Add this IV user to the Processed set before returning false to ensure that // all IV users are members of the set. See IVUsers::isIVUserOrOperand. if (!Processed.insert(I)) @@ -167,13 +167,12 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I, bool AddUserToIVUsers = false; if (LI->getLoopFor(User->getParent()) != L) { if (isa<PHINode>(User) || Processed.count(User) || - !AddUsersIfInteresting(User, SimpleLoopNests)) { + !AddUsersImpl(User, SimpleLoopNests)) { DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n' << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; } - } else if (Processed.count(User) - || !AddUsersIfInteresting(User, SimpleLoopNests)) { + } else if (Processed.count(User) || !AddUsersImpl(User, SimpleLoopNests)) { DEBUG(dbgs() << "FOUND USER: " << *User << '\n' << " OF SCEV: " << *ISE << '\n'); AddUserToIVUsers = true; @@ -197,6 +196,15 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I, return true; } +bool IVUsers::AddUsersIfInteresting(Instruction *I) { + // SCEVExpander can only handle users that are dominated by simplified loop + // entries. Keep track of all loops that are only dominated by other simple + // loops so we don't traverse the domtree for each user. + SmallPtrSet<Loop*,16> SimpleLoopNests; + + return AddUsersImpl(I, SimpleLoopNests); +} + IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) { IVUses.push_back(new IVStrideUse(this, User, Operand)); return IVUses.back(); @@ -222,16 +230,11 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) { SE = &getAnalysis<ScalarEvolution>(); TD = getAnalysisIfAvailable<TargetData>(); - // SCEVExpander can only handle users that are dominated by simplified loop - // entries. Keep track of all loops that are only dominated by other simple - // loops so we don't traverse the domtree for each user. - SmallPtrSet<Loop*,16> SimpleLoopNests; - // Find all uses of induction variables in this loop, and categorize // them by stride. Start by finding all of the PHI nodes in the header for // this loop. If they are induction variables, inspect their uses. for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) - (void)AddUsersIfInteresting(I, SimpleLoopNests); + (void)AddUsersIfInteresting(I); return false; } diff --git a/lib/Analysis/InlineCost.cpp b/lib/Analysis/InlineCost.cpp index dedbfeb..3e3d2ab 100644 --- a/lib/Analysis/InlineCost.cpp +++ b/lib/Analysis/InlineCost.cpp @@ -11,659 +11,1012 @@ // //===----------------------------------------------------------------------===// +#define DEBUG_TYPE "inline-cost" #include "llvm/Analysis/InlineCost.h" +#include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Support/CallSite.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/InstVisitor.h" +#include "llvm/Support/GetElementPtrTypeIterator.h" +#include "llvm/Support/raw_ostream.h" #include "llvm/CallingConv.h" #include "llvm/IntrinsicInst.h" +#include "llvm/Operator.h" +#include "llvm/GlobalAlias.h" #include "llvm/Target/TargetData.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SetVector.h" +#include "llvm/ADT/SmallVector.h" #include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/Statistic.h" using namespace llvm; -unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForConstant( - const CodeMetrics &Metrics, Value *V) { - unsigned Reduction = 0; - SmallVector<Value *, 4> Worklist; - Worklist.push_back(V); - do { - Value *V = Worklist.pop_back_val(); - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){ - User *U = *UI; - if (isa<BranchInst>(U) || isa<SwitchInst>(U)) { - // We will be able to eliminate all but one of the successors. - const TerminatorInst &TI = cast<TerminatorInst>(*U); - const unsigned NumSucc = TI.getNumSuccessors(); - unsigned Instrs = 0; - for (unsigned I = 0; I != NumSucc; ++I) - Instrs += Metrics.NumBBInsts.lookup(TI.getSuccessor(I)); - // We don't know which blocks will be eliminated, so use the average size. - Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc; - continue; - } +STATISTIC(NumCallsAnalyzed, "Number of call sites analyzed"); + +namespace { + +class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> { + typedef InstVisitor<CallAnalyzer, bool> Base; + friend class InstVisitor<CallAnalyzer, bool>; + + // TargetData if available, or null. + const TargetData *const TD; + + // The called function. + Function &F; + + int Threshold; + int Cost; + const bool AlwaysInline; + + bool IsRecursive; + bool ExposesReturnsTwice; + bool HasDynamicAlloca; + unsigned NumInstructions, NumVectorInstructions; + int FiftyPercentVectorBonus, TenPercentVectorBonus; + int VectorBonus; + + // While we walk the potentially-inlined instructions, we build up and + // maintain a mapping of simplified values specific to this callsite. The + // idea is to propagate any special information we have about arguments to + // this call through the inlinable section of the function, and account for + // likely simplifications post-inlining. The most important aspect we track + // is CFG altering simplifications -- when we prove a basic block dead, that + // can cause dramatic shifts in the cost of inlining a function. + DenseMap<Value *, Constant *> SimplifiedValues; + + // Keep track of the values which map back (through function arguments) to + // allocas on the caller stack which could be simplified through SROA. + DenseMap<Value *, Value *> SROAArgValues; + + // The mapping of caller Alloca values to their accumulated cost savings. If + // we have to disable SROA for one of the allocas, this tells us how much + // cost must be added. + DenseMap<Value *, int> SROAArgCosts; + + // Keep track of values which map to a pointer base and constant offset. + DenseMap<Value *, std::pair<Value *, APInt> > ConstantOffsetPtrs; + + // Custom simplification helper routines. + bool isAllocaDerivedArg(Value *V); + bool lookupSROAArgAndCost(Value *V, Value *&Arg, + DenseMap<Value *, int>::iterator &CostIt); + void disableSROA(DenseMap<Value *, int>::iterator CostIt); + void disableSROA(Value *V); + void accumulateSROACost(DenseMap<Value *, int>::iterator CostIt, + int InstructionCost); + bool handleSROACandidate(bool IsSROAValid, + DenseMap<Value *, int>::iterator CostIt, + int InstructionCost); + bool isGEPOffsetConstant(GetElementPtrInst &GEP); + bool accumulateGEPOffset(GEPOperator &GEP, APInt &Offset); + ConstantInt *stripAndComputeInBoundsConstantOffsets(Value *&V); + + // Custom analysis routines. + bool analyzeBlock(BasicBlock *BB); + + // Disable several entry points to the visitor so we don't accidentally use + // them by declaring but not defining them here. + void visit(Module *); void visit(Module &); + void visit(Function *); void visit(Function &); + void visit(BasicBlock *); void visit(BasicBlock &); + + // Provide base case for our instruction visit. + bool visitInstruction(Instruction &I); + + // Our visit overrides. + bool visitAlloca(AllocaInst &I); + bool visitPHI(PHINode &I); + bool visitGetElementPtr(GetElementPtrInst &I); + bool visitBitCast(BitCastInst &I); + bool visitPtrToInt(PtrToIntInst &I); + bool visitIntToPtr(IntToPtrInst &I); + bool visitCastInst(CastInst &I); + bool visitUnaryInstruction(UnaryInstruction &I); + bool visitICmp(ICmpInst &I); + bool visitSub(BinaryOperator &I); + bool visitBinaryOperator(BinaryOperator &I); + bool visitLoad(LoadInst &I); + bool visitStore(StoreInst &I); + bool visitCallSite(CallSite CS); + +public: + CallAnalyzer(const TargetData *TD, Function &Callee, int Threshold) + : TD(TD), F(Callee), Threshold(Threshold), Cost(0), + AlwaysInline(F.hasFnAttr(Attribute::AlwaysInline)), + IsRecursive(false), ExposesReturnsTwice(false), HasDynamicAlloca(false), + NumInstructions(0), NumVectorInstructions(0), + FiftyPercentVectorBonus(0), TenPercentVectorBonus(0), VectorBonus(0), + NumConstantArgs(0), NumConstantOffsetPtrArgs(0), NumAllocaArgs(0), + NumConstantPtrCmps(0), NumConstantPtrDiffs(0), + NumInstructionsSimplified(0), SROACostSavings(0), SROACostSavingsLost(0) { + } - // Figure out if this instruction will be removed due to simple constant - // propagation. - Instruction &Inst = cast<Instruction>(*U); - - // We can't constant propagate instructions which have effects or - // read memory. - // - // FIXME: It would be nice to capture the fact that a load from a - // pointer-to-constant-global is actually a *really* good thing to zap. - // Unfortunately, we don't know the pointer that may get propagated here, - // so we can't make this decision. - if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() || - isa<AllocaInst>(Inst)) - continue; + bool analyzeCall(CallSite CS); - bool AllOperandsConstant = true; - for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) - if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) { - AllOperandsConstant = false; - break; - } - if (!AllOperandsConstant) - continue; + int getThreshold() { return Threshold; } + int getCost() { return Cost; } - // We will get to remove this instruction... - Reduction += InlineConstants::InstrCost; + // Keep a bunch of stats about the cost savings found so we can print them + // out when debugging. + unsigned NumConstantArgs; + unsigned NumConstantOffsetPtrArgs; + unsigned NumAllocaArgs; + unsigned NumConstantPtrCmps; + unsigned NumConstantPtrDiffs; + unsigned NumInstructionsSimplified; + unsigned SROACostSavings; + unsigned SROACostSavingsLost; - // And any other instructions that use it which become constants - // themselves. - Worklist.push_back(&Inst); - } - } while (!Worklist.empty()); - return Reduction; -} + void dump(); +}; -static unsigned countCodeReductionForAllocaICmp(const CodeMetrics &Metrics, - ICmpInst *ICI) { - unsigned Reduction = 0; +} // namespace - // Bail if this is comparing against a non-constant; there is nothing we can - // do there. - if (!isa<Constant>(ICI->getOperand(1))) - return Reduction; +/// \brief Test whether the given value is an Alloca-derived function argument. +bool CallAnalyzer::isAllocaDerivedArg(Value *V) { + return SROAArgValues.count(V); +} - // An icmp pred (alloca, C) becomes true if the predicate is true when - // equal and false otherwise. - bool Result = ICI->isTrueWhenEqual(); +/// \brief Lookup the SROA-candidate argument and cost iterator which V maps to. +/// Returns false if V does not map to a SROA-candidate. +bool CallAnalyzer::lookupSROAArgAndCost( + Value *V, Value *&Arg, DenseMap<Value *, int>::iterator &CostIt) { + if (SROAArgValues.empty() || SROAArgCosts.empty()) + return false; - SmallVector<Instruction *, 4> Worklist; - Worklist.push_back(ICI); - do { - Instruction *U = Worklist.pop_back_val(); - Reduction += InlineConstants::InstrCost; - for (Value::use_iterator UI = U->use_begin(), UE = U->use_end(); - UI != UE; ++UI) { - Instruction *I = dyn_cast<Instruction>(*UI); - if (!I || I->mayHaveSideEffects()) continue; - if (I->getNumOperands() == 1) - Worklist.push_back(I); - if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) { - // If BO produces the same value as U, then the other operand is - // irrelevant and we can put it into the Worklist to continue - // deleting dead instructions. If BO produces the same value as the - // other operand, we can delete BO but that's it. - if (Result == true) { - if (BO->getOpcode() == Instruction::Or) - Worklist.push_back(I); - if (BO->getOpcode() == Instruction::And) - Reduction += InlineConstants::InstrCost; - } else { - if (BO->getOpcode() == Instruction::Or || - BO->getOpcode() == Instruction::Xor) - Reduction += InlineConstants::InstrCost; - if (BO->getOpcode() == Instruction::And) - Worklist.push_back(I); - } - } - if (BranchInst *BI = dyn_cast<BranchInst>(I)) { - BasicBlock *BB = BI->getSuccessor(Result ? 0 : 1); - if (BB->getSinglePredecessor()) - Reduction - += InlineConstants::InstrCost * Metrics.NumBBInsts.lookup(BB); - } - } - } while (!Worklist.empty()); + DenseMap<Value *, Value *>::iterator ArgIt = SROAArgValues.find(V); + if (ArgIt == SROAArgValues.end()) + return false; - return Reduction; + Arg = ArgIt->second; + CostIt = SROAArgCosts.find(Arg); + return CostIt != SROAArgCosts.end(); } -/// \brief Compute the reduction possible for a given instruction if we are able -/// to SROA an alloca. +/// \brief Disable SROA for the candidate marked by this cost iterator. /// -/// The reduction for this instruction is added to the SROAReduction output -/// parameter. Returns false if this instruction is expected to defeat SROA in -/// general. -static bool countCodeReductionForSROAInst(Instruction *I, - SmallVectorImpl<Value *> &Worklist, - unsigned &SROAReduction) { - if (LoadInst *LI = dyn_cast<LoadInst>(I)) { - if (!LI->isSimple()) - return false; - SROAReduction += InlineConstants::InstrCost; +/// This markes the candidate as no longer viable for SROA, and adds the cost +/// savings associated with it back into the inline cost measurement. +void CallAnalyzer::disableSROA(DenseMap<Value *, int>::iterator CostIt) { + // If we're no longer able to perform SROA we need to undo its cost savings + // and prevent subsequent analysis. + Cost += CostIt->second; + SROACostSavings -= CostIt->second; + SROACostSavingsLost += CostIt->second; + SROAArgCosts.erase(CostIt); +} + +/// \brief If 'V' maps to a SROA candidate, disable SROA for it. +void CallAnalyzer::disableSROA(Value *V) { + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(V, SROAArg, CostIt)) + disableSROA(CostIt); +} + +/// \brief Accumulate the given cost for a particular SROA candidate. +void CallAnalyzer::accumulateSROACost(DenseMap<Value *, int>::iterator CostIt, + int InstructionCost) { + CostIt->second += InstructionCost; + SROACostSavings += InstructionCost; +} + +/// \brief Helper for the common pattern of handling a SROA candidate. +/// Either accumulates the cost savings if the SROA remains valid, or disables +/// SROA for the candidate. +bool CallAnalyzer::handleSROACandidate(bool IsSROAValid, + DenseMap<Value *, int>::iterator CostIt, + int InstructionCost) { + if (IsSROAValid) { + accumulateSROACost(CostIt, InstructionCost); return true; } - if (StoreInst *SI = dyn_cast<StoreInst>(I)) { - if (!SI->isSimple()) + disableSROA(CostIt); + return false; +} + +/// \brief Check whether a GEP's indices are all constant. +/// +/// Respects any simplified values known during the analysis of this callsite. +bool CallAnalyzer::isGEPOffsetConstant(GetElementPtrInst &GEP) { + for (User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); I != E; ++I) + if (!isa<Constant>(*I) && !SimplifiedValues.lookup(*I)) return false; - SROAReduction += InlineConstants::InstrCost; - return true; - } - if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) { - // If the GEP has variable indices, we won't be able to do much with it. - if (!GEP->hasAllConstantIndices()) + return true; +} + +/// \brief Accumulate a constant GEP offset into an APInt if possible. +/// +/// Returns false if unable to compute the offset for any reason. Respects any +/// simplified values known during the analysis of this callsite. +bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) { + if (!TD) + return false; + + unsigned IntPtrWidth = TD->getPointerSizeInBits(); + assert(IntPtrWidth == Offset.getBitWidth()); + + for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP); + GTI != GTE; ++GTI) { + ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand()); + if (!OpC) + if (Constant *SimpleOp = SimplifiedValues.lookup(GTI.getOperand())) + OpC = dyn_cast<ConstantInt>(SimpleOp); + if (!OpC) return false; - // A non-zero GEP will likely become a mask operation after SROA. - if (GEP->hasAllZeroIndices()) - SROAReduction += InlineConstants::InstrCost; - Worklist.push_back(GEP); - return true; - } + if (OpC->isZero()) continue; - if (BitCastInst *BCI = dyn_cast<BitCastInst>(I)) { - // Track pointer through bitcasts. - Worklist.push_back(BCI); - SROAReduction += InlineConstants::InstrCost; - return true; + // Handle a struct index, which adds its field offset to the pointer. + if (StructType *STy = dyn_cast<StructType>(*GTI)) { + unsigned ElementIdx = OpC->getZExtValue(); + const StructLayout *SL = TD->getStructLayout(STy); + Offset += APInt(IntPtrWidth, SL->getElementOffset(ElementIdx)); + continue; + } + + APInt TypeSize(IntPtrWidth, TD->getTypeAllocSize(GTI.getIndexedType())); + Offset += OpC->getValue().sextOrTrunc(IntPtrWidth) * TypeSize; } + return true; +} + +bool CallAnalyzer::visitAlloca(AllocaInst &I) { + // FIXME: Check whether inlining will turn a dynamic alloca into a static + // alloca, and handle that case. + + // We will happily inline static alloca instructions or dynamic alloca + // instructions in always-inline situations. + if (AlwaysInline || I.isStaticAlloca()) + return Base::visitAlloca(I); + + // FIXME: This is overly conservative. Dynamic allocas are inefficient for + // a variety of reasons, and so we would like to not inline them into + // functions which don't currently have a dynamic alloca. This simply + // disables inlining altogether in the presence of a dynamic alloca. + HasDynamicAlloca = true; + return false; +} - // We just look for non-constant operands to ICmp instructions as those will - // defeat SROA. The actual reduction for these happens even without SROA. - if (ICmpInst *ICI = dyn_cast<ICmpInst>(I)) - return isa<Constant>(ICI->getOperand(1)); - - if (SelectInst *SI = dyn_cast<SelectInst>(I)) { - // SROA can handle a select of alloca iff all uses of the alloca are - // loads, and dereferenceable. We assume it's dereferenceable since - // we're told the input is an alloca. - for (Value::use_iterator UI = SI->use_begin(), UE = SI->use_end(); - UI != UE; ++UI) { - LoadInst *LI = dyn_cast<LoadInst>(*UI); - if (LI == 0 || !LI->isSimple()) +bool CallAnalyzer::visitPHI(PHINode &I) { + // FIXME: We should potentially be tracking values through phi nodes, + // especially when they collapse to a single value due to deleted CFG edges + // during inlining. + + // FIXME: We need to propagate SROA *disabling* through phi nodes, even + // though we don't want to propagate it's bonuses. The idea is to disable + // SROA if it *might* be used in an inappropriate manner. + + // Phi nodes are always zero-cost. + return true; +} + +bool CallAnalyzer::visitGetElementPtr(GetElementPtrInst &I) { + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + bool SROACandidate = lookupSROAArgAndCost(I.getPointerOperand(), + SROAArg, CostIt); + + // Try to fold GEPs of constant-offset call site argument pointers. This + // requires target data and inbounds GEPs. + if (TD && I.isInBounds()) { + // Check if we have a base + offset for the pointer. + Value *Ptr = I.getPointerOperand(); + std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Ptr); + if (BaseAndOffset.first) { + // Check if the offset of this GEP is constant, and if so accumulate it + // into Offset. + if (!accumulateGEPOffset(cast<GEPOperator>(I), BaseAndOffset.second)) { + // Non-constant GEPs aren't folded, and disable SROA. + if (SROACandidate) + disableSROA(CostIt); return false; + } + + // Add the result as a new mapping to Base + Offset. + ConstantOffsetPtrs[&I] = BaseAndOffset; + + // Also handle SROA candidates here, we already know that the GEP is + // all-constant indexed. + if (SROACandidate) + SROAArgValues[&I] = SROAArg; + + return true; } - // We don't know whether we'll be deleting the rest of the chain of - // instructions from the SelectInst on, because we don't know whether - // the other side of the select is also an alloca or not. + } + + if (isGEPOffsetConstant(I)) { + if (SROACandidate) + SROAArgValues[&I] = SROAArg; + + // Constant GEPs are modeled as free. return true; } - if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) { - switch (II->getIntrinsicID()) { - default: - return false; - case Intrinsic::memset: - case Intrinsic::memcpy: - case Intrinsic::memmove: - case Intrinsic::lifetime_start: - case Intrinsic::lifetime_end: - // SROA can usually chew through these intrinsics. - SROAReduction += InlineConstants::InstrCost; + // Variable GEPs will require math and will disable SROA. + if (SROACandidate) + disableSROA(CostIt); + return false; +} + +bool CallAnalyzer::visitBitCast(BitCastInst &I) { + // Propagate constants through bitcasts. + if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) + if (Constant *C = ConstantExpr::getBitCast(COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } + + // Track base/offsets through casts + std::pair<Value *, APInt> BaseAndOffset + = ConstantOffsetPtrs.lookup(I.getOperand(0)); + // Casts don't change the offset, just wrap it up. + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; + + // Also look for SROA candidates here. + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; + + // Bitcasts are always zero cost. + return true; +} + +bool CallAnalyzer::visitPtrToInt(PtrToIntInst &I) { + // Propagate constants through ptrtoint. + if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) + if (Constant *C = ConstantExpr::getPtrToInt(COp, I.getType())) { + SimplifiedValues[&I] = C; return true; } + + // Track base/offset pairs when converted to a plain integer provided the + // integer is large enough to represent the pointer. + unsigned IntegerSize = I.getType()->getScalarSizeInBits(); + if (TD && IntegerSize >= TD->getPointerSizeInBits()) { + std::pair<Value *, APInt> BaseAndOffset + = ConstantOffsetPtrs.lookup(I.getOperand(0)); + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; } - // If there is some other strange instruction, we're not going to be - // able to do much if we inline this. - return false; + // This is really weird. Technically, ptrtoint will disable SROA. However, + // unless that ptrtoint is *used* somewhere in the live basic blocks after + // inlining, it will be nuked, and SROA should proceed. All of the uses which + // would block SROA would also block SROA if applied directly to a pointer, + // and so we can just add the integer in here. The only places where SROA is + // preserved either cannot fire on an integer, or won't in-and-of themselves + // disable SROA (ext) w/o some later use that we would see and disable. + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; + + // A ptrtoint cast is free so long as the result is large enough to store the + // pointer, and a legal integer type. + return TD && TD->isLegalInteger(IntegerSize) && + IntegerSize >= TD->getPointerSizeInBits(); } -unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForAlloca( - const CodeMetrics &Metrics, Value *V) { - if (!V->getType()->isPointerTy()) return 0; // Not a pointer - unsigned Reduction = 0; - unsigned SROAReduction = 0; - bool CanSROAAlloca = true; +bool CallAnalyzer::visitIntToPtr(IntToPtrInst &I) { + // Propagate constants through ptrtoint. + if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) + if (Constant *C = ConstantExpr::getIntToPtr(COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; + } - SmallVector<Value *, 4> Worklist; - Worklist.push_back(V); - do { - Value *V = Worklist.pop_back_val(); - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); - UI != E; ++UI){ - Instruction *I = cast<Instruction>(*UI); + // Track base/offset pairs when round-tripped through a pointer without + // modifications provided the integer is not too large. + Value *Op = I.getOperand(0); + unsigned IntegerSize = Op->getType()->getScalarSizeInBits(); + if (TD && IntegerSize <= TD->getPointerSizeInBits()) { + std::pair<Value *, APInt> BaseAndOffset = ConstantOffsetPtrs.lookup(Op); + if (BaseAndOffset.first) + ConstantOffsetPtrs[&I] = BaseAndOffset; + } - if (ICmpInst *ICI = dyn_cast<ICmpInst>(I)) - Reduction += countCodeReductionForAllocaICmp(Metrics, ICI); + // "Propagate" SROA here in the same manner as we do for ptrtoint above. + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(Op, SROAArg, CostIt)) + SROAArgValues[&I] = SROAArg; - if (CanSROAAlloca) - CanSROAAlloca = countCodeReductionForSROAInst(I, Worklist, - SROAReduction); + // An inttoptr cast is free so long as the input is a legal integer type + // which doesn't contain values outside the range of a pointer. + return TD && TD->isLegalInteger(IntegerSize) && + IntegerSize <= TD->getPointerSizeInBits(); +} + +bool CallAnalyzer::visitCastInst(CastInst &I) { + // Propagate constants through ptrtoint. + if (Constant *COp = dyn_cast<Constant>(I.getOperand(0))) + if (Constant *C = ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) { + SimplifiedValues[&I] = C; + return true; } - } while (!Worklist.empty()); - return Reduction + (CanSROAAlloca ? SROAReduction : 0); + // Disable SROA in the face of arbitrary casts we don't whitelist elsewhere. + disableSROA(I.getOperand(0)); + + // No-op casts don't have any cost. + if (I.isLosslessCast()) + return true; + + // trunc to a native type is free (assuming the target has compare and + // shift-right of the same width). + if (TD && isa<TruncInst>(I) && + TD->isLegalInteger(TD->getTypeSizeInBits(I.getType()))) + return true; + + // Result of a cmp instruction is often extended (to be used by other + // cmp instructions, logical or return instructions). These are usually + // no-ops on most sane targets. + if (isa<CmpInst>(I.getOperand(0))) + return true; + + // Assume the rest of the casts require work. + return false; } -void InlineCostAnalyzer::FunctionInfo::countCodeReductionForPointerPair( - const CodeMetrics &Metrics, DenseMap<Value *, unsigned> &PointerArgs, - Value *V, unsigned ArgIdx) { - SmallVector<Value *, 4> Worklist; - Worklist.push_back(V); - do { - Value *V = Worklist.pop_back_val(); - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); - UI != E; ++UI){ - Instruction *I = cast<Instruction>(*UI); - - if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) { - // If the GEP has variable indices, we won't be able to do much with it. - if (!GEP->hasAllConstantIndices()) - continue; - // Unless the GEP is in-bounds, some comparisons will be non-constant. - // Fortunately, the real-world cases where this occurs uses in-bounds - // GEPs, and so we restrict the optimization to them here. - if (!GEP->isInBounds()) - continue; +bool CallAnalyzer::visitUnaryInstruction(UnaryInstruction &I) { + Value *Operand = I.getOperand(0); + Constant *Ops[1] = { dyn_cast<Constant>(Operand) }; + if (Ops[0] || (Ops[0] = SimplifiedValues.lookup(Operand))) + if (Constant *C = ConstantFoldInstOperands(I.getOpcode(), I.getType(), + Ops, TD)) { + SimplifiedValues[&I] = C; + return true; + } - // Constant indices just change the constant offset. Add the resulting - // value both to our worklist for this argument, and to the set of - // viable paired values with future arguments. - PointerArgs[GEP] = ArgIdx; - Worklist.push_back(GEP); - continue; + // Disable any SROA on the argument to arbitrary unary operators. + disableSROA(Operand); + + return false; +} + +bool CallAnalyzer::visitICmp(ICmpInst &I) { + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + // First try to handle simplified comparisons. + if (!isa<Constant>(LHS)) + if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) + LHS = SimpleLHS; + if (!isa<Constant>(RHS)) + if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) + RHS = SimpleRHS; + if (Constant *CLHS = dyn_cast<Constant>(LHS)) + if (Constant *CRHS = dyn_cast<Constant>(RHS)) + if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { + SimplifiedValues[&I] = C; + return true; } - // Track pointer through casts. Even when the result is not a pointer, it - // remains a constant relative to constants derived from other constant - // pointers. - if (CastInst *CI = dyn_cast<CastInst>(I)) { - PointerArgs[CI] = ArgIdx; - Worklist.push_back(CI); - continue; + // Otherwise look for a comparison between constant offset pointers with + // a common base. + Value *LHSBase, *RHSBase; + APInt LHSOffset, RHSOffset; + llvm::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); + if (LHSBase) { + llvm::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); + if (RHSBase && LHSBase == RHSBase) { + // We have common bases, fold the icmp to a constant based on the + // offsets. + Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); + Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); + if (Constant *C = ConstantExpr::getICmp(I.getPredicate(), CLHS, CRHS)) { + SimplifiedValues[&I] = C; + ++NumConstantPtrCmps; + return true; } + } + } - // There are two instructions which produce a strict constant value when - // applied to two related pointer values. Ignore everything else. - if (!isa<ICmpInst>(I) && I->getOpcode() != Instruction::Sub) - continue; - assert(I->getNumOperands() == 2); - - // Ensure that the two operands are in our set of potentially paired - // pointers (or are derived from them). - Value *OtherArg = I->getOperand(0); - if (OtherArg == V) - OtherArg = I->getOperand(1); - DenseMap<Value *, unsigned>::const_iterator ArgIt - = PointerArgs.find(OtherArg); - if (ArgIt == PointerArgs.end()) - continue; - std::pair<unsigned, unsigned> ArgPair(ArgIt->second, ArgIdx); - if (ArgPair.first > ArgPair.second) - std::swap(ArgPair.first, ArgPair.second); + // If the comparison is an equality comparison with null, we can simplify it + // for any alloca-derived argument. + if (I.isEquality() && isa<ConstantPointerNull>(I.getOperand(1))) + if (isAllocaDerivedArg(I.getOperand(0))) { + // We can actually predict the result of comparisons between an + // alloca-derived value and null. Note that this fires regardless of + // SROA firing. + bool IsNotEqual = I.getPredicate() == CmpInst::ICMP_NE; + SimplifiedValues[&I] = IsNotEqual ? ConstantInt::getTrue(I.getType()) + : ConstantInt::getFalse(I.getType()); + return true; + } - PointerArgPairWeights[ArgPair] - += countCodeReductionForConstant(Metrics, I); + // Finally check for SROA candidates in comparisons. + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { + if (isa<ConstantPointerNull>(I.getOperand(1))) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; } - } while (!Worklist.empty()); -} -/// analyzeFunction - Fill in the current structure with information gleaned -/// from the specified function. -void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F, - const TargetData *TD) { - Metrics.analyzeFunction(F, TD); - - // A function with exactly one return has it removed during the inlining - // process (see InlineFunction), so don't count it. - // FIXME: This knowledge should really be encoded outside of FunctionInfo. - if (Metrics.NumRets==1) - --Metrics.NumInsts; - - ArgumentWeights.reserve(F->arg_size()); - DenseMap<Value *, unsigned> PointerArgs; - unsigned ArgIdx = 0; - for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; - ++I, ++ArgIdx) { - // Count how much code can be eliminated if one of the arguments is - // a constant or an alloca. - ArgumentWeights.push_back(ArgInfo(countCodeReductionForConstant(Metrics, I), - countCodeReductionForAlloca(Metrics, I))); - - // If the argument is a pointer, also check for pairs of pointers where - // knowing a fixed offset between them allows simplification. This pattern - // arises mostly due to STL algorithm patterns where pointers are used as - // random access iterators. - if (!I->getType()->isPointerTy()) - continue; - PointerArgs[I] = ArgIdx; - countCodeReductionForPointerPair(Metrics, PointerArgs, I, ArgIdx); + disableSROA(CostIt); } -} -/// NeverInline - returns true if the function should never be inlined into -/// any caller -bool InlineCostAnalyzer::FunctionInfo::NeverInline() { - return (Metrics.exposesReturnsTwice || Metrics.isRecursive || - Metrics.containsIndirectBr); + return false; } -// ConstantFunctionBonus - Figure out how much of a bonus we can get for -// possibly devirtualizing a function. We'll subtract the size of the function -// we may wish to inline from the indirect call bonus providing a limit on -// growth. Leave an upper limit of 0 for the bonus - we don't want to penalize -// inlining because we decide we don't want to give a bonus for -// devirtualizing. -int InlineCostAnalyzer::ConstantFunctionBonus(CallSite CS, Constant *C) { +bool CallAnalyzer::visitSub(BinaryOperator &I) { + // Try to handle a special case: we can fold computing the difference of two + // constant-related pointers. + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + Value *LHSBase, *RHSBase; + APInt LHSOffset, RHSOffset; + llvm::tie(LHSBase, LHSOffset) = ConstantOffsetPtrs.lookup(LHS); + if (LHSBase) { + llvm::tie(RHSBase, RHSOffset) = ConstantOffsetPtrs.lookup(RHS); + if (RHSBase && LHSBase == RHSBase) { + // We have common bases, fold the subtract to a constant based on the + // offsets. + Constant *CLHS = ConstantInt::get(LHS->getContext(), LHSOffset); + Constant *CRHS = ConstantInt::get(RHS->getContext(), RHSOffset); + if (Constant *C = ConstantExpr::getSub(CLHS, CRHS)) { + SimplifiedValues[&I] = C; + ++NumConstantPtrDiffs; + return true; + } + } + } + + // Otherwise, fall back to the generic logic for simplifying and handling + // instructions. + return Base::visitSub(I); +} - // This could just be NULL. - if (!C) return 0; +bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) { + Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); + if (!isa<Constant>(LHS)) + if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS)) + LHS = SimpleLHS; + if (!isa<Constant>(RHS)) + if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS)) + RHS = SimpleRHS; + Value *SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, TD); + if (Constant *C = dyn_cast_or_null<Constant>(SimpleV)) { + SimplifiedValues[&I] = C; + return true; + } - Function *F = dyn_cast<Function>(C); - if (!F) return 0; + // Disable any SROA on arguments to arbitrary, unsimplified binary operators. + disableSROA(LHS); + disableSROA(RHS); - int Bonus = InlineConstants::IndirectCallBonus + getInlineSize(CS, F); - return (Bonus > 0) ? 0 : Bonus; + return false; } -// CountBonusForConstant - Figure out an approximation for how much per-call -// performance boost we can expect if the specified value is constant. -int InlineCostAnalyzer::CountBonusForConstant(Value *V, Constant *C) { - unsigned Bonus = 0; - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){ - User *U = *UI; - if (CallInst *CI = dyn_cast<CallInst>(U)) { - // Turning an indirect call into a direct call is a BIG win - if (CI->getCalledValue() == V) - Bonus += ConstantFunctionBonus(CallSite(CI), C); - } else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) { - // Turning an indirect call into a direct call is a BIG win - if (II->getCalledValue() == V) - Bonus += ConstantFunctionBonus(CallSite(II), C); +bool CallAnalyzer::visitLoad(LoadInst &I) { + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { + if (I.isSimple()) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; } - // FIXME: Eliminating conditional branches and switches should - // also yield a per-call performance boost. - else { - // Figure out the bonuses that wll accrue due to simple constant - // propagation. - Instruction &Inst = cast<Instruction>(*U); - - // We can't constant propagate instructions which have effects or - // read memory. - // - // FIXME: It would be nice to capture the fact that a load from a - // pointer-to-constant-global is actually a *really* good thing to zap. - // Unfortunately, we don't know the pointer that may get propagated here, - // so we can't make this decision. - if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() || - isa<AllocaInst>(Inst)) - continue; - bool AllOperandsConstant = true; - for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) - if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) { - AllOperandsConstant = false; - break; - } + disableSROA(CostIt); + } - if (AllOperandsConstant) - Bonus += CountBonusForConstant(&Inst); + return false; +} + +bool CallAnalyzer::visitStore(StoreInst &I) { + Value *SROAArg; + DenseMap<Value *, int>::iterator CostIt; + if (lookupSROAArgAndCost(I.getOperand(0), SROAArg, CostIt)) { + if (I.isSimple()) { + accumulateSROACost(CostIt, InlineConstants::InstrCost); + return true; } + + disableSROA(CostIt); } - return Bonus; + return false; } -int InlineCostAnalyzer::getInlineSize(CallSite CS, Function *Callee) { - // Get information about the callee. - FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee]; - - // If we haven't calculated this information yet, do so now. - if (CalleeFI->Metrics.NumBlocks == 0) - CalleeFI->analyzeFunction(Callee, TD); - - // InlineCost - This value measures how good of an inline candidate this call - // site is to inline. A lower inline cost make is more likely for the call to - // be inlined. This value may go negative. - // - int InlineCost = 0; - - // Compute any size reductions we can expect due to arguments being passed into - // the function. - // - unsigned ArgNo = 0; - CallSite::arg_iterator I = CS.arg_begin(); - for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end(); - FI != FE; ++I, ++FI, ++ArgNo) { - - // If an alloca is passed in, inlining this function is likely to allow - // significant future optimization possibilities (like scalar promotion, and - // scalarization), so encourage the inlining of the function. - // - if (isa<AllocaInst>(I)) - InlineCost -= CalleeFI->ArgumentWeights[ArgNo].AllocaWeight; - - // If this is a constant being passed into the function, use the argument - // weights calculated for the callee to determine how much will be folded - // away with this information. - else if (isa<Constant>(I)) - InlineCost -= CalleeFI->ArgumentWeights[ArgNo].ConstantWeight; +bool CallAnalyzer::visitCallSite(CallSite CS) { + if (CS.isCall() && cast<CallInst>(CS.getInstruction())->canReturnTwice() && + !F.hasFnAttr(Attribute::ReturnsTwice)) { + // This aborts the entire analysis. + ExposesReturnsTwice = true; + return false; + } + + if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CS.getInstruction())) { + switch (II->getIntrinsicID()) { + default: + return Base::visitCallSite(CS); + + case Intrinsic::dbg_declare: + case Intrinsic::dbg_value: + case Intrinsic::invariant_start: + case Intrinsic::invariant_end: + case Intrinsic::lifetime_start: + case Intrinsic::lifetime_end: + case Intrinsic::memset: + case Intrinsic::memcpy: + case Intrinsic::memmove: + case Intrinsic::objectsize: + case Intrinsic::ptr_annotation: + case Intrinsic::var_annotation: + // SROA can usually chew through these intrinsics and they have no cost + // so don't pay the price of analyzing them in detail. + return true; + } } - const DenseMap<std::pair<unsigned, unsigned>, unsigned> &ArgPairWeights - = CalleeFI->PointerArgPairWeights; - for (DenseMap<std::pair<unsigned, unsigned>, unsigned>::const_iterator I - = ArgPairWeights.begin(), E = ArgPairWeights.end(); - I != E; ++I) - if (CS.getArgument(I->first.first)->stripInBoundsConstantOffsets() == - CS.getArgument(I->first.second)->stripInBoundsConstantOffsets()) - InlineCost -= I->second; + if (Function *F = CS.getCalledFunction()) { + if (F == CS.getInstruction()->getParent()->getParent()) { + // This flag will fully abort the analysis, so don't bother with anything + // else. + IsRecursive = true; + return false; + } - // Each argument passed in has a cost at both the caller and the callee - // sides. Measurements show that each argument costs about the same as an - // instruction. - InlineCost -= (CS.arg_size() * InlineConstants::InstrCost); + if (!callIsSmall(F)) { + // We account for the average 1 instruction per call argument setup + // here. + Cost += CS.arg_size() * InlineConstants::InstrCost; - // Now that we have considered all of the factors that make the call site more - // likely to be inlined, look at factors that make us not want to inline it. + // Everything other than inline ASM will also have a significant cost + // merely from making the call. + if (!isa<InlineAsm>(CS.getCalledValue())) + Cost += InlineConstants::CallPenalty; + } - // Calls usually take a long time, so they make the inlining gain smaller. - InlineCost += CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty; + return Base::visitCallSite(CS); + } - // Look at the size of the callee. Each instruction counts as 5. - InlineCost += CalleeFI->Metrics.NumInsts * InlineConstants::InstrCost; + // Otherwise we're in a very special case -- an indirect function call. See + // if we can be particularly clever about this. + Value *Callee = CS.getCalledValue(); + + // First, pay the price of the argument setup. We account for the average + // 1 instruction per call argument setup here. + Cost += CS.arg_size() * InlineConstants::InstrCost; + + // Next, check if this happens to be an indirect function call to a known + // function in this inline context. If not, we've done all we can. + Function *F = dyn_cast_or_null<Function>(SimplifiedValues.lookup(Callee)); + if (!F) + return Base::visitCallSite(CS); + + // If we have a constant that we are calling as a function, we can peer + // through it and see the function target. This happens not infrequently + // during devirtualization and so we want to give it a hefty bonus for + // inlining, but cap that bonus in the event that inlining wouldn't pan + // out. Pretend to inline the function, with a custom threshold. + CallAnalyzer CA(TD, *F, InlineConstants::IndirectCallThreshold); + if (CA.analyzeCall(CS)) { + // We were able to inline the indirect call! Subtract the cost from the + // bonus we want to apply, but don't go below zero. + Cost -= std::max(0, InlineConstants::IndirectCallThreshold - CA.getCost()); + } - return InlineCost; + return Base::visitCallSite(CS); } -int InlineCostAnalyzer::getInlineBonuses(CallSite CS, Function *Callee) { - // Get information about the callee. - FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee]; - - // If we haven't calculated this information yet, do so now. - if (CalleeFI->Metrics.NumBlocks == 0) - CalleeFI->analyzeFunction(Callee, TD); - - bool isDirectCall = CS.getCalledFunction() == Callee; - Instruction *TheCall = CS.getInstruction(); - int Bonus = 0; - - // If there is only one call of the function, and it has internal linkage, - // make it almost guaranteed to be inlined. - // - if (Callee->hasLocalLinkage() && Callee->hasOneUse() && isDirectCall) - Bonus += InlineConstants::LastCallToStaticBonus; - - // If the instruction after the call, or if the normal destination of the - // invoke is an unreachable instruction, the function is noreturn. As such, - // there is little point in inlining this. - if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) { - if (isa<UnreachableInst>(II->getNormalDest()->begin())) - Bonus += InlineConstants::NoreturnPenalty; - } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall))) - Bonus += InlineConstants::NoreturnPenalty; - - // If this function uses the coldcc calling convention, prefer not to inline - // it. - if (Callee->getCallingConv() == CallingConv::Cold) - Bonus += InlineConstants::ColdccPenalty; - - // Add to the inline quality for properties that make the call valuable to - // inline. This includes factors that indicate that the result of inlining - // the function will be optimizable. Currently this just looks at arguments - // passed into the function. - // - CallSite::arg_iterator I = CS.arg_begin(); - for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end(); - FI != FE; ++I, ++FI) - // Compute any constant bonus due to inlining we want to give here. - if (isa<Constant>(I)) - Bonus += CountBonusForConstant(FI, cast<Constant>(I)); - - return Bonus; +bool CallAnalyzer::visitInstruction(Instruction &I) { + // We found something we don't understand or can't handle. Mark any SROA-able + // values in the operand list as no longer viable. + for (User::op_iterator OI = I.op_begin(), OE = I.op_end(); OI != OE; ++OI) + disableSROA(*OI); + + return false; } -// getInlineCost - The heuristic used to determine if we should inline the -// function call or not. -// -InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS) { - return getInlineCost(CS, CS.getCalledFunction()); + +/// \brief Analyze a basic block for its contribution to the inline cost. +/// +/// This method walks the analyzer over every instruction in the given basic +/// block and accounts for their cost during inlining at this callsite. It +/// aborts early if the threshold has been exceeded or an impossible to inline +/// construct has been detected. It returns false if inlining is no longer +/// viable, and true if inlining remains viable. +bool CallAnalyzer::analyzeBlock(BasicBlock *BB) { + for (BasicBlock::iterator I = BB->begin(), E = llvm::prior(BB->end()); + I != E; ++I) { + ++NumInstructions; + if (isa<ExtractElementInst>(I) || I->getType()->isVectorTy()) + ++NumVectorInstructions; + + // If the instruction simplified to a constant, there is no cost to this + // instruction. Visit the instructions using our InstVisitor to account for + // all of the per-instruction logic. The visit tree returns true if we + // consumed the instruction in any way, and false if the instruction's base + // cost should count against inlining. + if (Base::visit(I)) + ++NumInstructionsSimplified; + else + Cost += InlineConstants::InstrCost; + + // If the visit this instruction detected an uninlinable pattern, abort. + if (IsRecursive || ExposesReturnsTwice || HasDynamicAlloca) + return false; + + if (NumVectorInstructions > NumInstructions/2) + VectorBonus = FiftyPercentVectorBonus; + else if (NumVectorInstructions > NumInstructions/10) + VectorBonus = TenPercentVectorBonus; + else + VectorBonus = 0; + + // Check if we've past the threshold so we don't spin in huge basic + // blocks that will never inline. + if (!AlwaysInline && Cost > (Threshold + VectorBonus)) + return false; + } + + return true; } -InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee) { - Instruction *TheCall = CS.getInstruction(); - Function *Caller = TheCall->getParent()->getParent(); +/// \brief Compute the base pointer and cumulative constant offsets for V. +/// +/// This strips all constant offsets off of V, leaving it the base pointer, and +/// accumulates the total constant offset applied in the returned constant. It +/// returns 0 if V is not a pointer, and returns the constant '0' if there are +/// no constant offsets applied. +ConstantInt *CallAnalyzer::stripAndComputeInBoundsConstantOffsets(Value *&V) { + if (!TD || !V->getType()->isPointerTy()) + return 0; + + unsigned IntPtrWidth = TD->getPointerSizeInBits(); + APInt Offset = APInt::getNullValue(IntPtrWidth); + + // Even though we don't look through PHI nodes, we could be called on an + // instruction in an unreachable block, which may be on a cycle. + SmallPtrSet<Value *, 4> Visited; + Visited.insert(V); + do { + if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { + if (!GEP->isInBounds() || !accumulateGEPOffset(*GEP, Offset)) + return 0; + V = GEP->getPointerOperand(); + } else if (Operator::getOpcode(V) == Instruction::BitCast) { + V = cast<Operator>(V)->getOperand(0); + } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) { + if (GA->mayBeOverridden()) + break; + V = GA->getAliasee(); + } else { + break; + } + assert(V->getType()->isPointerTy() && "Unexpected operand type!"); + } while (Visited.insert(V)); - // Don't inline functions which can be redefined at link-time to mean - // something else. Don't inline functions marked noinline or call sites - // marked noinline. - if (Callee->mayBeOverridden() || Callee->hasFnAttr(Attribute::NoInline) || - CS.isNoInline()) - return llvm::InlineCost::getNever(); + Type *IntPtrTy = TD->getIntPtrType(V->getContext()); + return cast<ConstantInt>(ConstantInt::get(IntPtrTy, Offset)); +} - // Get information about the callee. - FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee]; +/// \brief Analyze a call site for potential inlining. +/// +/// Returns true if inlining this call is viable, and false if it is not +/// viable. It computes the cost and adjusts the threshold based on numerous +/// factors and heuristics. If this method returns false but the computed cost +/// is below the computed threshold, then inlining was forcibly disabled by +/// some artifact of the rountine. +bool CallAnalyzer::analyzeCall(CallSite CS) { + ++NumCallsAnalyzed; + + // Track whether the post-inlining function would have more than one basic + // block. A single basic block is often intended for inlining. Balloon the + // threshold by 50% until we pass the single-BB phase. + bool SingleBB = true; + int SingleBBBonus = Threshold / 2; + Threshold += SingleBBBonus; + + // Unless we are always-inlining, perform some tweaks to the cost and + // threshold based on the direct callsite information. + if (!AlwaysInline) { + // We want to more aggressively inline vector-dense kernels, so up the + // threshold, and we'll lower it if the % of vector instructions gets too + // low. + assert(NumInstructions == 0); + assert(NumVectorInstructions == 0); + FiftyPercentVectorBonus = Threshold; + TenPercentVectorBonus = Threshold / 2; + + // Subtract off one instruction per call argument as those will be free after + // inlining. + Cost -= CS.arg_size() * InlineConstants::InstrCost; + + // If there is only one call of the function, and it has internal linkage, + // the cost of inlining it drops dramatically. + if (F.hasLocalLinkage() && F.hasOneUse() && &F == CS.getCalledFunction()) + Cost += InlineConstants::LastCallToStaticBonus; + + // If the instruction after the call, or if the normal destination of the + // invoke is an unreachable instruction, the function is noreturn. As such, + // there is little point in inlining this unless there is literally zero cost. + if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) { + if (isa<UnreachableInst>(II->getNormalDest()->begin())) + Threshold = 1; + } else if (isa<UnreachableInst>(++BasicBlock::iterator(CS.getInstruction()))) + Threshold = 1; + + // If this function uses the coldcc calling convention, prefer not to inline + // it. + if (F.getCallingConv() == CallingConv::Cold) + Cost += InlineConstants::ColdccPenalty; + + // Check if we're done. This can happen due to bonuses and penalties. + if (Cost > Threshold) + return false; + } - // If we haven't calculated this information yet, do so now. - if (CalleeFI->Metrics.NumBlocks == 0) - CalleeFI->analyzeFunction(Callee, TD); + if (F.empty()) + return true; - // If we should never inline this, return a huge cost. - if (CalleeFI->NeverInline()) - return InlineCost::getNever(); + // Track whether we've seen a return instruction. The first return + // instruction is free, as at least one will usually disappear in inlining. + bool HasReturn = false; + + // Populate our simplified values by mapping from function arguments to call + // arguments with known important simplifications. + CallSite::arg_iterator CAI = CS.arg_begin(); + for (Function::arg_iterator FAI = F.arg_begin(), FAE = F.arg_end(); + FAI != FAE; ++FAI, ++CAI) { + assert(CAI != CS.arg_end()); + if (Constant *C = dyn_cast<Constant>(CAI)) + SimplifiedValues[FAI] = C; + + Value *PtrArg = *CAI; + if (ConstantInt *C = stripAndComputeInBoundsConstantOffsets(PtrArg)) { + ConstantOffsetPtrs[FAI] = std::make_pair(PtrArg, C->getValue()); + + // We can SROA any pointer arguments derived from alloca instructions. + if (isa<AllocaInst>(PtrArg)) { + SROAArgValues[FAI] = PtrArg; + SROAArgCosts[PtrArg] = 0; + } + } + } + NumConstantArgs = SimplifiedValues.size(); + NumConstantOffsetPtrArgs = ConstantOffsetPtrs.size(); + NumAllocaArgs = SROAArgValues.size(); + + // The worklist of live basic blocks in the callee *after* inlining. We avoid + // adding basic blocks of the callee which can be proven to be dead for this + // particular call site in order to get more accurate cost estimates. This + // requires a somewhat heavyweight iteration pattern: we need to walk the + // basic blocks in a breadth-first order as we insert live successors. To + // accomplish this, prioritizing for small iterations because we exit after + // crossing our threshold, we use a small-size optimized SetVector. + typedef SetVector<BasicBlock *, SmallVector<BasicBlock *, 16>, + SmallPtrSet<BasicBlock *, 16> > BBSetVector; + BBSetVector BBWorklist; + BBWorklist.insert(&F.getEntryBlock()); + // Note that we *must not* cache the size, this loop grows the worklist. + for (unsigned Idx = 0; Idx != BBWorklist.size(); ++Idx) { + // Bail out the moment we cross the threshold. This means we'll under-count + // the cost, but only when undercounting doesn't matter. + if (!AlwaysInline && Cost > (Threshold + VectorBonus)) + break; + + BasicBlock *BB = BBWorklist[Idx]; + if (BB->empty()) + continue; - // FIXME: It would be nice to kill off CalleeFI->NeverInline. Then we - // could move this up and avoid computing the FunctionInfo for - // things we are going to just return always inline for. This - // requires handling setjmp somewhere else, however. - if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline)) - return InlineCost::getAlways(); + // Handle the terminator cost here where we can track returns and other + // function-wide constructs. + TerminatorInst *TI = BB->getTerminator(); + + // We never want to inline functions that contain an indirectbr. This is + // incorrect because all the blockaddress's (in static global initializers + // for example) would be referring to the original function, and this indirect + // jump would jump from the inlined copy of the function into the original + // function which is extremely undefined behavior. + // FIXME: This logic isn't really right; we can safely inline functions + // with indirectbr's as long as no other function or global references the + // blockaddress of a block within the current function. And as a QOI issue, + // if someone is using a blockaddress without an indirectbr, and that + // reference somehow ends up in another function or global, we probably + // don't want to inline this function. + if (isa<IndirectBrInst>(TI)) + return false; - if (CalleeFI->Metrics.usesDynamicAlloca) { - // Get information about the caller. - FunctionInfo &CallerFI = CachedFunctionInfo[Caller]; + if (!HasReturn && isa<ReturnInst>(TI)) + HasReturn = true; + else + Cost += InlineConstants::InstrCost; - // If we haven't calculated this information yet, do so now. - if (CallerFI.Metrics.NumBlocks == 0) { - CallerFI.analyzeFunction(Caller, TD); + // Analyze the cost of this block. If we blow through the threshold, this + // returns false, and we can bail on out. + if (!analyzeBlock(BB)) { + if (IsRecursive || ExposesReturnsTwice || HasDynamicAlloca) + return false; + break; + } - // Recompute the CalleeFI pointer, getting Caller could have invalidated - // it. - CalleeFI = &CachedFunctionInfo[Callee]; + // Add in the live successors by first checking whether we have terminator + // that may be simplified based on the values simplified by this call. + if (BranchInst *BI = dyn_cast<BranchInst>(TI)) { + if (BI->isConditional()) { + Value *Cond = BI->getCondition(); + if (ConstantInt *SimpleCond + = dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) { + BBWorklist.insert(BI->getSuccessor(SimpleCond->isZero() ? 1 : 0)); + continue; + } + } + } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) { + Value *Cond = SI->getCondition(); + if (ConstantInt *SimpleCond + = dyn_cast_or_null<ConstantInt>(SimplifiedValues.lookup(Cond))) { + BBWorklist.insert(SI->findCaseValue(SimpleCond).getCaseSuccessor()); + continue; + } } - // Don't inline a callee with dynamic alloca into a caller without them. - // Functions containing dynamic alloca's are inefficient in various ways; - // don't create more inefficiency. - if (!CallerFI.Metrics.usesDynamicAlloca) - return InlineCost::getNever(); + // If we're unable to select a particular successor, just count all of + // them. + for (unsigned TIdx = 0, TSize = TI->getNumSuccessors(); TIdx != TSize; ++TIdx) + BBWorklist.insert(TI->getSuccessor(TIdx)); + + // If we had any successors at this point, than post-inlining is likely to + // have them as well. Note that we assume any basic blocks which existed + // due to branches or switches which folded above will also fold after + // inlining. + if (SingleBB && TI->getNumSuccessors() > 1) { + // Take off the bonus we applied to the threshold. + Threshold -= SingleBBBonus; + SingleBB = false; + } } - // InlineCost - This value measures how good of an inline candidate this call - // site is to inline. A lower inline cost make is more likely for the call to - // be inlined. This value may go negative due to the fact that bonuses - // are negative numbers. - // - int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee); - return llvm::InlineCost::get(InlineCost); -} + Threshold += VectorBonus; -// getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a -// higher threshold to determine if the function call should be inlined. -float InlineCostAnalyzer::getInlineFudgeFactor(CallSite CS) { - Function *Callee = CS.getCalledFunction(); - - // Get information about the callee. - FunctionInfo &CalleeFI = CachedFunctionInfo[Callee]; - - // If we haven't calculated this information yet, do so now. - if (CalleeFI.Metrics.NumBlocks == 0) - CalleeFI.analyzeFunction(Callee, TD); - - float Factor = 1.0f; - // Single BB functions are often written to be inlined. - if (CalleeFI.Metrics.NumBlocks == 1) - Factor += 0.5f; - - // Be more aggressive if the function contains a good chunk (if it mades up - // at least 10% of the instructions) of vector instructions. - if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/2) - Factor += 2.0f; - else if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/10) - Factor += 1.5f; - return Factor; + return AlwaysInline || Cost < Threshold; } -/// growCachedCostInfo - update the cached cost info for Caller after Callee has -/// been inlined. -void -InlineCostAnalyzer::growCachedCostInfo(Function *Caller, Function *Callee) { - CodeMetrics &CallerMetrics = CachedFunctionInfo[Caller].Metrics; +/// \brief Dump stats about this call's analysis. +void CallAnalyzer::dump() { +#define DEBUG_PRINT_STAT(x) llvm::dbgs() << " " #x ": " << x << "\n" + DEBUG_PRINT_STAT(NumConstantArgs); + DEBUG_PRINT_STAT(NumConstantOffsetPtrArgs); + DEBUG_PRINT_STAT(NumAllocaArgs); + DEBUG_PRINT_STAT(NumConstantPtrCmps); + DEBUG_PRINT_STAT(NumConstantPtrDiffs); + DEBUG_PRINT_STAT(NumInstructionsSimplified); + DEBUG_PRINT_STAT(SROACostSavings); + DEBUG_PRINT_STAT(SROACostSavingsLost); +#undef DEBUG_PRINT_STAT +} - // For small functions we prefer to recalculate the cost for better accuracy. - if (CallerMetrics.NumBlocks < 10 && CallerMetrics.NumInsts < 1000) { - resetCachedCostInfo(Caller); - return; - } +InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, int Threshold) { + return getInlineCost(CS, CS.getCalledFunction(), Threshold); +} - // For large functions, we can save a lot of computation time by skipping - // recalculations. - if (CallerMetrics.NumCalls > 0) - --CallerMetrics.NumCalls; +InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee, + int Threshold) { + // Don't inline functions which can be redefined at link-time to mean + // something else. Don't inline functions marked noinline or call sites + // marked noinline. + if (!Callee || Callee->mayBeOverridden() || + Callee->hasFnAttr(Attribute::NoInline) || CS.isNoInline()) + return llvm::InlineCost::getNever(); - if (Callee == 0) return; + DEBUG(llvm::dbgs() << " Analyzing call of " << Callee->getName() << "...\n"); - CodeMetrics &CalleeMetrics = CachedFunctionInfo[Callee].Metrics; + CallAnalyzer CA(TD, *Callee, Threshold); + bool ShouldInline = CA.analyzeCall(CS); - // If we don't have metrics for the callee, don't recalculate them just to - // update an approximation in the caller. Instead, just recalculate the - // caller info from scratch. - if (CalleeMetrics.NumBlocks == 0) { - resetCachedCostInfo(Caller); - return; - } + DEBUG(CA.dump()); - // Since CalleeMetrics were already calculated, we know that the CallerMetrics - // reference isn't invalidated: both were in the DenseMap. - CallerMetrics.usesDynamicAlloca |= CalleeMetrics.usesDynamicAlloca; - - // FIXME: If any of these three are true for the callee, the callee was - // not inlined into the caller, so I think they're redundant here. - CallerMetrics.exposesReturnsTwice |= CalleeMetrics.exposesReturnsTwice; - CallerMetrics.isRecursive |= CalleeMetrics.isRecursive; - CallerMetrics.containsIndirectBr |= CalleeMetrics.containsIndirectBr; - - CallerMetrics.NumInsts += CalleeMetrics.NumInsts; - CallerMetrics.NumBlocks += CalleeMetrics.NumBlocks; - CallerMetrics.NumCalls += CalleeMetrics.NumCalls; - CallerMetrics.NumVectorInsts += CalleeMetrics.NumVectorInsts; - CallerMetrics.NumRets += CalleeMetrics.NumRets; - - // analyzeBasicBlock counts each function argument as an inst. - if (CallerMetrics.NumInsts >= Callee->arg_size()) - CallerMetrics.NumInsts -= Callee->arg_size(); - else - CallerMetrics.NumInsts = 0; - - // We are not updating the argument weights. We have already determined that - // Caller is a fairly large function, so we accept the loss of precision. -} + // Check if there was a reason to force inlining or no inlining. + if (!ShouldInline && CA.getCost() < CA.getThreshold()) + return InlineCost::getNever(); + if (ShouldInline && CA.getCost() >= CA.getThreshold()) + return InlineCost::getAlways(); -/// clear - empty the cache of inline costs -void InlineCostAnalyzer::clear() { - CachedFunctionInfo.clear(); + return llvm::InlineCost::get(CA.getCost(), CA.getThreshold()); } diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 72e33d1..16e7a72 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -21,6 +21,7 @@ #include "llvm/GlobalAlias.h" #include "llvm/Operator.h" #include "llvm/ADT/Statistic.h" +#include "llvm/ADT/SetVector.h" #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/ConstantFolding.h" @@ -709,7 +710,7 @@ static Constant *stripAndComputeConstantOffsets(const TargetData &TD, Visited.insert(V); do { if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) { - if (!accumulateGEPOffset(TD, GEP, Offset)) + if (!GEP->isInBounds() || !accumulateGEPOffset(TD, GEP, Offset)) break; V = GEP->getPointerOperand(); } else if (Operator::getOpcode(V) == Instruction::BitCast) { @@ -1590,6 +1591,45 @@ static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred, return 0; } +static Constant *computePointerICmp(const TargetData &TD, + CmpInst::Predicate Pred, + Value *LHS, Value *RHS) { + // We can only fold certain predicates on pointer comparisons. + switch (Pred) { + default: + return 0; + + // Equality comaprisons are easy to fold. + case CmpInst::ICMP_EQ: + case CmpInst::ICMP_NE: + break; + + // We can only handle unsigned relational comparisons because 'inbounds' on + // a GEP only protects against unsigned wrapping. + case CmpInst::ICMP_UGT: + case CmpInst::ICMP_UGE: + case CmpInst::ICMP_ULT: + case CmpInst::ICMP_ULE: + // However, we have to switch them to their signed variants to handle + // negative indices from the base pointer. + Pred = ICmpInst::getSignedPredicate(Pred); + break; + } + + Constant *LHSOffset = stripAndComputeConstantOffsets(TD, LHS); + if (!LHSOffset) + return 0; + Constant *RHSOffset = stripAndComputeConstantOffsets(TD, RHS); + if (!RHSOffset) + return 0; + + // If LHS and RHS are not related via constant offsets to the same base + // value, there is nothing we can do here. + if (LHS != RHS) + return 0; + + return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset); +} /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can /// fold the result. If not, this returns null. @@ -2310,7 +2350,12 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, return getFalse(ITy); } - // Simplify comparisons of GEPs. + // Simplify comparisons of related pointers using a powerful, recursive + // GEP-walk when we have target data available.. + if (Q.TD && LHS->getType()->isPointerTy() && RHS->getType()->isPointerTy()) + if (Constant *C = computePointerICmp(*Q.TD, Pred, LHS, RHS)) + return C; + if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) { if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) { if (GLHS->getPointerOperand() == GRHS->getPointerOperand() && @@ -2818,58 +2863,84 @@ Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD, return Result == I ? UndefValue::get(I->getType()) : Result; } -/// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then -/// delete the From instruction. In addition to a basic RAUW, this does a -/// recursive simplification of the newly formed instructions. This catches -/// things where one simplification exposes other opportunities. This only -/// simplifies and deletes scalar operations, it does not change the CFG. +/// \brief Implementation of recursive simplification through an instructions +/// uses. /// -void llvm::ReplaceAndSimplifyAllUses(Instruction *From, Value *To, - const TargetData *TD, - const TargetLibraryInfo *TLI, - const DominatorTree *DT) { - assert(From != To && "ReplaceAndSimplifyAllUses(X,X) is not valid!"); - - // FromHandle/ToHandle - This keeps a WeakVH on the from/to values so that - // we can know if it gets deleted out from under us or replaced in a - // recursive simplification. - WeakVH FromHandle(From); - WeakVH ToHandle(To); - - while (!From->use_empty()) { - // Update the instruction to use the new value. - Use &TheUse = From->use_begin().getUse(); - Instruction *User = cast<Instruction>(TheUse.getUser()); - TheUse = To; - - // Check to see if the instruction can be folded due to the operand - // replacement. For example changing (or X, Y) into (or X, -1) can replace - // the 'or' with -1. - Value *SimplifiedVal; - { - // Sanity check to make sure 'User' doesn't dangle across - // SimplifyInstruction. - AssertingVH<> UserHandle(User); - - SimplifiedVal = SimplifyInstruction(User, TD, TLI, DT); - if (SimplifiedVal == 0) continue; - } +/// This is the common implementation of the recursive simplification routines. +/// If we have a pre-simplified value in 'SimpleV', that is forcibly used to +/// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of +/// instructions to process and attempt to simplify it using +/// InstructionSimplify. +/// +/// This routine returns 'true' only when *it* simplifies something. The passed +/// in simplified value does not count toward this. +static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + bool Simplified = false; + SmallSetVector<Instruction *, 8> Worklist; + + // If we have an explicit value to collapse to, do that round of the + // simplification loop by hand initially. + if (SimpleV) { + for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE; + ++UI) + if (*UI != I) + Worklist.insert(cast<Instruction>(*UI)); + + // Replace the instruction with its simplified value. + I->replaceAllUsesWith(SimpleV); + + // Gracefully handle edge cases where the instruction is not wired into any + // parent block. + if (I->getParent()) + I->eraseFromParent(); + } else { + Worklist.insert(I); + } + + // Note that we must test the size on each iteration, the worklist can grow. + for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) { + I = Worklist[Idx]; + + // See if this instruction simplifies. + SimpleV = SimplifyInstruction(I, TD, TLI, DT); + if (!SimpleV) + continue; + + Simplified = true; - // Recursively simplify this user to the new value. - ReplaceAndSimplifyAllUses(User, SimplifiedVal, TD, TLI, DT); - From = dyn_cast_or_null<Instruction>((Value*)FromHandle); - To = ToHandle; + // Stash away all the uses of the old instruction so we can check them for + // recursive simplifications after a RAUW. This is cheaper than checking all + // uses of To on the recursive step in most cases. + for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE; + ++UI) + Worklist.insert(cast<Instruction>(*UI)); - assert(ToHandle && "To value deleted by recursive simplification?"); + // Replace the instruction with its simplified value. + I->replaceAllUsesWith(SimpleV); - // If the recursive simplification ended up revisiting and deleting - // 'From' then we're done. - if (From == 0) - return; + // Gracefully handle edge cases where the instruction is not wired into any + // parent block. + if (I->getParent()) + I->eraseFromParent(); } + return Simplified; +} - // If 'From' has value handles referring to it, do a real RAUW to update them. - From->replaceAllUsesWith(To); +bool llvm::recursivelySimplifyInstruction(Instruction *I, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + return replaceAndRecursivelySimplifyImpl(I, 0, TD, TLI, DT); +} - From->eraseFromParent(); +bool llvm::replaceAndRecursivelySimplify(Instruction *I, Value *SimpleV, + const TargetData *TD, + const TargetLibraryInfo *TLI, + const DominatorTree *DT) { + assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!"); + assert(SimpleV && "Must provide a simplified value."); + return replaceAndRecursivelySimplifyImpl(I, SimpleV, TD, TLI, DT); } diff --git a/lib/Analysis/Lint.cpp b/lib/Analysis/Lint.cpp index 971065f..83bdf52 100644 --- a/lib/Analysis/Lint.cpp +++ b/lib/Analysis/Lint.cpp @@ -416,9 +416,8 @@ void Lint::visitMemoryReference(Instruction &I, if (Align != 0) { unsigned BitWidth = TD->getTypeSizeInBits(Ptr->getType()); - APInt Mask = APInt::getAllOnesValue(BitWidth), - KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); - ComputeMaskedBits(Ptr, Mask, KnownZero, KnownOne, TD); + APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); + ComputeMaskedBits(Ptr, KnownZero, KnownOne, TD); Assert1(!(KnownOne & APInt::getLowBitsSet(BitWidth, Log2_32(Align))), "Undefined behavior: Memory reference address is misaligned", &I); } @@ -476,9 +475,8 @@ static bool isZero(Value *V, TargetData *TD) { if (isa<UndefValue>(V)) return true; unsigned BitWidth = cast<IntegerType>(V->getType())->getBitWidth(); - APInt Mask = APInt::getAllOnesValue(BitWidth), - KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); - ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD); + APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); + ComputeMaskedBits(V, KnownZero, KnownOne, TD); return KnownZero.isAllOnesValue(); } diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index 858cc64..f7a60a1 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -205,6 +205,17 @@ bool Loop::isLoopSimplifyForm() const { return getLoopPreheader() && getLoopLatch() && hasDedicatedExits(); } +/// isSafeToClone - Return true if the loop body is safe to clone in practice. +/// Routines that reform the loop CFG and split edges often fail on indirectbr. +bool Loop::isSafeToClone() const { + // Return false if any loop blocks contain indirectbrs. + for (Loop::block_iterator I = block_begin(), E = block_end(); I != E; ++I) { + if (isa<IndirectBrInst>((*I)->getTerminator())) + return false; + } + return true; +} + /// hasDedicatedExits - Return true if no exit block for the loop /// has a predecessor that is outside the loop. bool Loop::hasDedicatedExits() const { diff --git a/lib/Analysis/LoopPass.cpp b/lib/Analysis/LoopPass.cpp index 5ba1f40..aba700a 100644 --- a/lib/Analysis/LoopPass.cpp +++ b/lib/Analysis/LoopPass.cpp @@ -14,10 +14,8 @@ //===----------------------------------------------------------------------===// #include "llvm/Analysis/LoopPass.h" -#include "llvm/DebugInfoProbe.h" #include "llvm/Assembly/PrintModulePass.h" #include "llvm/Support/Debug.h" -#include "llvm/Support/ManagedStatic.h" #include "llvm/Support/Timer.h" using namespace llvm; @@ -54,20 +52,6 @@ char PrintLoopPass::ID = 0; } //===----------------------------------------------------------------------===// -// DebugInfoProbe - -static DebugInfoProbeInfo *TheDebugProbe; -static void createDebugInfoProbe() { - if (TheDebugProbe) return; - - // Constructed the first time this is called. This guarantees that the - // object will be constructed, if -enable-debug-info-probe is set, - // before static globals, thus it will be destroyed before them. - static ManagedStatic<DebugInfoProbeInfo> DIP; - TheDebugProbe = &*DIP; -} - -//===----------------------------------------------------------------------===// // LPPassManager // @@ -195,7 +179,6 @@ void LPPassManager::getAnalysisUsage(AnalysisUsage &Info) const { bool LPPassManager::runOnFunction(Function &F) { LI = &getAnalysis<LoopInfo>(); bool Changed = false; - createDebugInfoProbe(); // Collect inherited analysis from Module level pass manager. populateInheritedAnalysis(TPM->activeStack); @@ -227,21 +210,19 @@ bool LPPassManager::runOnFunction(Function &F) { // Run all passes on the current Loop. for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) { LoopPass *P = getContainedPass(Index); + dumpPassInfo(P, EXECUTION_MSG, ON_LOOP_MSG, CurrentLoop->getHeader()->getName()); dumpRequiredSet(P); initializeAnalysisImpl(P); - if (TheDebugProbe) - TheDebugProbe->initialize(P, F); + { PassManagerPrettyStackEntry X(P, *CurrentLoop->getHeader()); TimeRegion PassTimer(getPassTimer(P)); Changed |= P->runOnLoop(CurrentLoop, *this); } - if (TheDebugProbe) - TheDebugProbe->finalize(P, F); if (Changed) dumpPassInfo(P, MODIFICATION_MSG, ON_LOOP_MSG, diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 0c0ceeb..205227c 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -3261,9 +3261,8 @@ ScalarEvolution::GetMinTrailingZeros(const SCEV *S) { if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { // For a SCEVUnknown, ask ValueTracking. unsigned BitWidth = getTypeSizeInBits(U->getType()); - APInt Mask = APInt::getAllOnesValue(BitWidth); APInt Zeros(BitWidth, 0), Ones(BitWidth, 0); - ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones); + ComputeMaskedBits(U->getValue(), Zeros, Ones); return Zeros.countTrailingOnes(); } @@ -3401,9 +3400,8 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) { if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { // For a SCEVUnknown, ask ValueTracking. - APInt Mask = APInt::getAllOnesValue(BitWidth); APInt Zeros(BitWidth, 0), Ones(BitWidth, 0); - ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD); + ComputeMaskedBits(U->getValue(), Zeros, Ones, TD); if (Ones == ~Zeros + 1) return setUnsignedRange(U, ConservativeResult); return setUnsignedRange(U, @@ -3660,9 +3658,8 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) { // knew about to reconstruct a low-bits mask value. unsigned LZ = A.countLeadingZeros(); unsigned BitWidth = A.getBitWidth(); - APInt AllOnes = APInt::getAllOnesValue(BitWidth); APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); - ComputeMaskedBits(U->getOperand(0), AllOnes, KnownZero, KnownOne, TD); + ComputeMaskedBits(U->getOperand(0), KnownZero, KnownOne, TD); APInt EffectiveMask = APInt::getLowBitsSet(BitWidth, BitWidth - LZ); @@ -4619,6 +4616,10 @@ ScalarEvolution::ComputeLoadConstantCompareExitLimit( Indexes.push_back(0); } + // Loop-invariant loads may be a byproduct of loop optimization. Skip them. + if (!VarIdx) + return getCouldNotCompute(); + // Okay, we know we have a (load (gep GV, 0, X)) comparison with a constant. // Check to see if X is a loop variant variable value now. const SCEV *Idx = getSCEV(VarIdx); @@ -6845,7 +6846,7 @@ ScalarEvolution::computeBlockDisposition(const SCEV *S, const BasicBlock *BB) { return ProperlyDominatesBlock; case scCouldNotCompute: llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!"); - default: + default: llvm_unreachable("Unknown SCEV kind!"); } } diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 01e00ca..a430f62 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -20,8 +20,10 @@ #include "llvm/GlobalAlias.h" #include "llvm/IntrinsicInst.h" #include "llvm/LLVMContext.h" +#include "llvm/Metadata.h" #include "llvm/Operator.h" #include "llvm/Target/TargetData.h" +#include "llvm/Support/ConstantRange.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/PatternMatch.h" @@ -42,7 +44,6 @@ static unsigned getBitWidth(Type *Ty, const TargetData *TD) { } static void ComputeMaskedBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW, - const APInt &Mask, APInt &KnownZero, APInt &KnownOne, APInt &KnownZero2, APInt &KnownOne2, const TargetData *TD, unsigned Depth) { @@ -52,11 +53,11 @@ static void ComputeMaskedBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW, // than C (i.e. no wrap-around can happen). For example, 20-X is // positive if we can prove that X is >= 0 and < 16. if (!CLHS->getValue().isNegative()) { - unsigned BitWidth = Mask.getBitWidth(); + unsigned BitWidth = KnownZero.getBitWidth(); unsigned NLZ = (CLHS->getValue()+1).countLeadingZeros(); // NLZ can't be BitWidth with no sign bit APInt MaskV = APInt::getHighBitsSet(BitWidth, NLZ+1); - llvm::ComputeMaskedBits(Op1, MaskV, KnownZero2, KnownOne2, TD, Depth+1); + llvm::ComputeMaskedBits(Op1, KnownZero2, KnownOne2, TD, Depth+1); // If all of the MaskV bits are known to be zero, then we know the // output top bits are zero, because we now know that the output is @@ -64,27 +65,25 @@ static void ComputeMaskedBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW, if ((KnownZero2 & MaskV) == MaskV) { unsigned NLZ2 = CLHS->getValue().countLeadingZeros(); // Top bits known zero. - KnownZero = APInt::getHighBitsSet(BitWidth, NLZ2) & Mask; + KnownZero = APInt::getHighBitsSet(BitWidth, NLZ2); } } } } - unsigned BitWidth = Mask.getBitWidth(); + unsigned BitWidth = KnownZero.getBitWidth(); // If one of the operands has trailing zeros, then the bits that the // other operand has in those bit positions will be preserved in the // result. For an add, this works with either operand. For a subtract, // this only works if the known zeros are in the right operand. APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0); - APInt Mask2 = APInt::getLowBitsSet(BitWidth, - BitWidth - Mask.countLeadingZeros()); - llvm::ComputeMaskedBits(Op0, Mask2, LHSKnownZero, LHSKnownOne, TD, Depth+1); + llvm::ComputeMaskedBits(Op0, LHSKnownZero, LHSKnownOne, TD, Depth+1); assert((LHSKnownZero & LHSKnownOne) == 0 && "Bits known to be one AND zero?"); unsigned LHSKnownZeroOut = LHSKnownZero.countTrailingOnes(); - llvm::ComputeMaskedBits(Op1, Mask2, KnownZero2, KnownOne2, TD, Depth+1); + llvm::ComputeMaskedBits(Op1, KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); unsigned RHSKnownZeroOut = KnownZero2.countTrailingOnes(); @@ -109,7 +108,7 @@ static void ComputeMaskedBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW, } // Are we still trying to solve for the sign bit? - if (Mask.isNegative() && !KnownZero.isNegative() && !KnownOne.isNegative()) { + if (!KnownZero.isNegative() && !KnownOne.isNegative()) { if (NSW) { if (Add) { // Adding two positive numbers can't wrap into negative @@ -131,21 +130,19 @@ static void ComputeMaskedBitsAddSub(bool Add, Value *Op0, Value *Op1, bool NSW, } static void ComputeMaskedBitsMul(Value *Op0, Value *Op1, bool NSW, - const APInt &Mask, APInt &KnownZero, APInt &KnownOne, APInt &KnownZero2, APInt &KnownOne2, const TargetData *TD, unsigned Depth) { - unsigned BitWidth = Mask.getBitWidth(); - APInt Mask2 = APInt::getAllOnesValue(BitWidth); - ComputeMaskedBits(Op1, Mask2, KnownZero, KnownOne, TD, Depth+1); - ComputeMaskedBits(Op0, Mask2, KnownZero2, KnownOne2, TD, Depth+1); + unsigned BitWidth = KnownZero.getBitWidth(); + ComputeMaskedBits(Op1, KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(Op0, KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); bool isKnownNegative = false; bool isKnownNonNegative = false; // If the multiplication is known not to overflow, compute the sign bit. - if (Mask.isNegative() && NSW) { + if (NSW) { if (Op0 == Op1) { // The product of a number with itself is non-negative. isKnownNonNegative = true; @@ -182,7 +179,6 @@ static void ComputeMaskedBitsMul(Value *Op0, Value *Op1, bool NSW, LeadZ = std::min(LeadZ, BitWidth); KnownZero = APInt::getLowBitsSet(BitWidth, TrailZ) | APInt::getHighBitsSet(BitWidth, LeadZ); - KnownZero &= Mask; // Only make use of no-wrap flags if we failed to compute the sign bit // directly. This matters if the multiplication always overflows, in @@ -195,10 +191,28 @@ static void ComputeMaskedBitsMul(Value *Op0, Value *Op1, bool NSW, KnownOne.setBit(BitWidth - 1); } -/// ComputeMaskedBits - Determine which of the bits specified in Mask are -/// known to be either zero or one and return them in the KnownZero/KnownOne -/// bit sets. This code only analyzes bits in Mask, in order to short-circuit -/// processing. +void llvm::computeMaskedBitsLoad(const MDNode &Ranges, APInt &KnownZero) { + unsigned BitWidth = KnownZero.getBitWidth(); + unsigned NumRanges = Ranges.getNumOperands() / 2; + assert(NumRanges >= 1); + + // Use the high end of the ranges to find leading zeros. + unsigned MinLeadingZeros = BitWidth; + for (unsigned i = 0; i < NumRanges; ++i) { + ConstantInt *Lower = cast<ConstantInt>(Ranges.getOperand(2*i + 0)); + ConstantInt *Upper = cast<ConstantInt>(Ranges.getOperand(2*i + 1)); + ConstantRange Range(Lower->getValue(), Upper->getValue()); + if (Range.isWrappedSet()) + MinLeadingZeros = 0; // -1 has no zeros + unsigned LeadingZeros = (Upper->getValue() - 1).countLeadingZeros(); + MinLeadingZeros = std::min(LeadingZeros, MinLeadingZeros); + } + + KnownZero = APInt::getHighBitsSet(BitWidth, MinLeadingZeros); +} +/// ComputeMaskedBits - Determine which of the bits are known to be either zero +/// or one and return them in the KnownZero/KnownOne bit sets. +/// /// NOTE: we cannot consider 'undef' to be "IsZero" here. The problem is that /// we cannot optimize based on the assumption that it is zero without changing /// it to be an explicit zero. If we don't change it to zero, other code could @@ -208,15 +222,15 @@ static void ComputeMaskedBitsMul(Value *Op0, Value *Op1, bool NSW, /// /// This function is defined on values with integer type, values with pointer /// type (but only if TD is non-null), and vectors of integers. In the case -/// where V is a vector, the mask, known zero, and known one values are the +/// where V is a vector, known zero, and known one values are the /// same width as the vector element, and the bit is set only if it is true /// for all of the elements in the vector. -void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, - APInt &KnownZero, APInt &KnownOne, +void llvm::ComputeMaskedBits(Value *V, APInt &KnownZero, APInt &KnownOne, const TargetData *TD, unsigned Depth) { assert(V && "No Value?"); assert(Depth <= MaxDepth && "Limit Search Depth"); - unsigned BitWidth = Mask.getBitWidth(); + unsigned BitWidth = KnownZero.getBitWidth(); + assert((V->getType()->isIntOrIntVectorTy() || V->getType()->getScalarType()->isPointerTy()) && "Not integer or pointer type!"); @@ -230,15 +244,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { // We know all of the bits for a constant! - KnownOne = CI->getValue() & Mask; - KnownZero = ~KnownOne & Mask; + KnownOne = CI->getValue(); + KnownZero = ~KnownOne; return; } // Null and aggregate-zero are all-zeros. if (isa<ConstantPointerNull>(V) || isa<ConstantAggregateZero>(V)) { KnownOne.clearAllBits(); - KnownZero = Mask; + KnownZero = APInt::getAllOnesValue(BitWidth); return; } // Handle a constant vector by taking the intersection of the known bits of @@ -275,8 +289,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, } } if (Align > 0) - KnownZero = Mask & APInt::getLowBitsSet(BitWidth, - CountTrailingZeros_32(Align)); + KnownZero = APInt::getLowBitsSet(BitWidth, + CountTrailingZeros_32(Align)); else KnownZero.clearAllBits(); KnownOne.clearAllBits(); @@ -288,8 +302,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (GA->mayBeOverridden()) { KnownZero.clearAllBits(); KnownOne.clearAllBits(); } else { - ComputeMaskedBits(GA->getAliasee(), Mask, KnownZero, KnownOne, - TD, Depth+1); + ComputeMaskedBits(GA->getAliasee(), KnownZero, KnownOne, TD, Depth+1); } return; } @@ -298,15 +311,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // Get alignment information off byval arguments if specified in the IR. if (A->hasByValAttr()) if (unsigned Align = A->getParamAlignment()) - KnownZero = Mask & APInt::getLowBitsSet(BitWidth, - CountTrailingZeros_32(Align)); + KnownZero = APInt::getLowBitsSet(BitWidth, + CountTrailingZeros_32(Align)); return; } // Start out not knowing anything. KnownZero.clearAllBits(); KnownOne.clearAllBits(); - if (Depth == MaxDepth || Mask == 0) + if (Depth == MaxDepth) return; // Limit search depth. Operator *I = dyn_cast<Operator>(V); @@ -315,12 +328,14 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, APInt KnownZero2(KnownZero), KnownOne2(KnownOne); switch (I->getOpcode()) { default: break; + case Instruction::Load: + if (MDNode *MD = cast<LoadInst>(I)->getMetadata(LLVMContext::MD_range)) + computeMaskedBitsLoad(*MD, KnownZero); + return; case Instruction::And: { // If either the LHS or the RHS are Zero, the result is zero. - ComputeMaskedBits(I->getOperand(1), Mask, KnownZero, KnownOne, TD, Depth+1); - APInt Mask2(Mask & ~KnownZero); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero2, KnownOne2, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); @@ -331,10 +346,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, return; } case Instruction::Or: { - ComputeMaskedBits(I->getOperand(1), Mask, KnownZero, KnownOne, TD, Depth+1); - APInt Mask2(Mask & ~KnownOne); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero2, KnownOne2, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); @@ -345,9 +358,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, return; } case Instruction::Xor: { - ComputeMaskedBits(I->getOperand(1), Mask, KnownZero, KnownOne, TD, Depth+1); - ComputeMaskedBits(I->getOperand(0), Mask, KnownZero2, KnownOne2, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); @@ -361,34 +373,30 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, case Instruction::Mul: { bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); ComputeMaskedBitsMul(I->getOperand(0), I->getOperand(1), NSW, - Mask, KnownZero, KnownOne, KnownZero2, KnownOne2, - TD, Depth); + KnownZero, KnownOne, KnownZero2, KnownOne2, TD, Depth); break; } case Instruction::UDiv: { // For the purposes of computing leading zeros we can conservatively // treat a udiv as a logical right shift by the power of 2 known to // be less than the denominator. - APInt AllOnes = APInt::getAllOnesValue(BitWidth); - ComputeMaskedBits(I->getOperand(0), - AllOnes, KnownZero2, KnownOne2, TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1); unsigned LeadZ = KnownZero2.countLeadingOnes(); KnownOne2.clearAllBits(); KnownZero2.clearAllBits(); - ComputeMaskedBits(I->getOperand(1), - AllOnes, KnownZero2, KnownOne2, TD, Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1); unsigned RHSUnknownLeadingOnes = KnownOne2.countLeadingZeros(); if (RHSUnknownLeadingOnes != BitWidth) LeadZ = std::min(BitWidth, LeadZ + BitWidth - RHSUnknownLeadingOnes - 1); - KnownZero = APInt::getHighBitsSet(BitWidth, LeadZ) & Mask; + KnownZero = APInt::getHighBitsSet(BitWidth, LeadZ); return; } case Instruction::Select: - ComputeMaskedBits(I->getOperand(2), Mask, KnownZero, KnownOne, TD, Depth+1); - ComputeMaskedBits(I->getOperand(1), Mask, KnownZero2, KnownOne2, TD, + ComputeMaskedBits(I->getOperand(2), KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?"); @@ -421,11 +429,9 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, else SrcBitWidth = SrcTy->getScalarSizeInBits(); - APInt MaskIn = Mask.zextOrTrunc(SrcBitWidth); KnownZero = KnownZero.zextOrTrunc(SrcBitWidth); KnownOne = KnownOne.zextOrTrunc(SrcBitWidth); - ComputeMaskedBits(I->getOperand(0), MaskIn, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); KnownZero = KnownZero.zextOrTrunc(BitWidth); KnownOne = KnownOne.zextOrTrunc(BitWidth); // Any top bits are known to be zero. @@ -439,8 +445,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // TODO: For now, not handling conversions like: // (bitcast i64 %x to <2 x i32>) !I->getType()->isVectorTy()) { - ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); return; } break; @@ -449,11 +454,9 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // Compute the bits in the result that are not present in the input. unsigned SrcBitWidth = I->getOperand(0)->getType()->getScalarSizeInBits(); - APInt MaskIn = Mask.trunc(SrcBitWidth); KnownZero = KnownZero.trunc(SrcBitWidth); KnownOne = KnownOne.trunc(SrcBitWidth); - ComputeMaskedBits(I->getOperand(0), MaskIn, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); KnownZero = KnownZero.zext(BitWidth); KnownOne = KnownOne.zext(BitWidth); @@ -470,9 +473,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0 if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) { uint64_t ShiftAmt = SA->getLimitedValue(BitWidth); - APInt Mask2(Mask.lshr(ShiftAmt)); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); KnownZero <<= ShiftAmt; KnownOne <<= ShiftAmt; @@ -487,9 +488,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, uint64_t ShiftAmt = SA->getLimitedValue(BitWidth); // Unsigned shift right. - APInt Mask2(Mask.shl(ShiftAmt)); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero,KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero,KnownOne, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); KnownZero = APIntOps::lshr(KnownZero, ShiftAmt); KnownOne = APIntOps::lshr(KnownOne, ShiftAmt); @@ -505,9 +504,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, uint64_t ShiftAmt = SA->getLimitedValue(BitWidth-1); // Signed shift right. - APInt Mask2(Mask.shl(ShiftAmt)); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); KnownZero = APIntOps::lshr(KnownZero, ShiftAmt); KnownOne = APIntOps::lshr(KnownOne, ShiftAmt); @@ -523,15 +520,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, case Instruction::Sub: { bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); ComputeMaskedBitsAddSub(false, I->getOperand(0), I->getOperand(1), NSW, - Mask, KnownZero, KnownOne, KnownZero2, KnownOne2, - TD, Depth); + KnownZero, KnownOne, KnownZero2, KnownOne2, TD, + Depth); break; } case Instruction::Add: { bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap(); ComputeMaskedBitsAddSub(true, I->getOperand(0), I->getOperand(1), NSW, - Mask, KnownZero, KnownOne, KnownZero2, KnownOne2, - TD, Depth); + KnownZero, KnownOne, KnownZero2, KnownOne2, TD, + Depth); break; } case Instruction::SRem: @@ -539,9 +536,7 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, APInt RA = Rem->getValue().abs(); if (RA.isPowerOf2()) { APInt LowBits = RA - 1; - APInt Mask2 = LowBits | APInt::getSignBit(BitWidth); - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero2, KnownOne2, TD, - Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero2, KnownOne2, TD, Depth+1); // The low bits of the first operand are unchanged by the srem. KnownZero = KnownZero2 & LowBits; @@ -557,19 +552,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (KnownOne2[BitWidth-1] && ((KnownOne2 & LowBits) != 0)) KnownOne |= ~LowBits; - KnownZero &= Mask; - KnownOne &= Mask; - assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); } } // The sign bit is the LHS's sign bit, except when the result of the // remainder is zero. - if (Mask.isNegative() && KnownZero.isNonNegative()) { - APInt Mask2 = APInt::getSignBit(BitWidth); + if (KnownZero.isNonNegative()) { APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0); - ComputeMaskedBits(I->getOperand(0), Mask2, LHSKnownZero, LHSKnownOne, TD, + ComputeMaskedBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, TD, Depth+1); // If it's known zero, our sign bit is also zero. if (LHSKnownZero.isNegative()) @@ -582,27 +573,24 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, APInt RA = Rem->getValue(); if (RA.isPowerOf2()) { APInt LowBits = (RA - 1); - APInt Mask2 = LowBits & Mask; - KnownZero |= ~LowBits & Mask; - ComputeMaskedBits(I->getOperand(0), Mask2, KnownZero, KnownOne, TD, + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero |= ~LowBits; + KnownOne &= LowBits; break; } } // Since the result is less than or equal to either operand, any leading // zero bits in either operand must also exist in the result. - APInt AllOnes = APInt::getAllOnesValue(BitWidth); - ComputeMaskedBits(I->getOperand(0), AllOnes, KnownZero, KnownOne, - TD, Depth+1); - ComputeMaskedBits(I->getOperand(1), AllOnes, KnownZero2, KnownOne2, - TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), KnownZero, KnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(1), KnownZero2, KnownOne2, TD, Depth+1); unsigned Leaders = std::max(KnownZero.countLeadingOnes(), KnownZero2.countLeadingOnes()); KnownOne.clearAllBits(); - KnownZero = APInt::getHighBitsSet(BitWidth, Leaders) & Mask; + KnownZero = APInt::getHighBitsSet(BitWidth, Leaders); break; } @@ -613,17 +601,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, Align = TD->getABITypeAlignment(AI->getType()->getElementType()); if (Align > 0) - KnownZero = Mask & APInt::getLowBitsSet(BitWidth, - CountTrailingZeros_32(Align)); + KnownZero = APInt::getLowBitsSet(BitWidth, CountTrailingZeros_32(Align)); break; } case Instruction::GetElementPtr: { // Analyze all of the subscripts of this getelementptr instruction // to determine if we can prove known low zero bits. - APInt LocalMask = APInt::getAllOnesValue(BitWidth); APInt LocalKnownZero(BitWidth, 0), LocalKnownOne(BitWidth, 0); - ComputeMaskedBits(I->getOperand(0), LocalMask, - LocalKnownZero, LocalKnownOne, TD, Depth+1); + ComputeMaskedBits(I->getOperand(0), LocalKnownZero, LocalKnownOne, TD, + Depth+1); unsigned TrailZ = LocalKnownZero.countTrailingOnes(); gep_type_iterator GTI = gep_type_begin(I); @@ -643,17 +629,15 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (!IndexedTy->isSized()) return; unsigned GEPOpiBits = Index->getType()->getScalarSizeInBits(); uint64_t TypeSize = TD ? TD->getTypeAllocSize(IndexedTy) : 1; - LocalMask = APInt::getAllOnesValue(GEPOpiBits); LocalKnownZero = LocalKnownOne = APInt(GEPOpiBits, 0); - ComputeMaskedBits(Index, LocalMask, - LocalKnownZero, LocalKnownOne, TD, Depth+1); + ComputeMaskedBits(Index, LocalKnownZero, LocalKnownOne, TD, Depth+1); TrailZ = std::min(TrailZ, unsigned(CountTrailingZeros_64(TypeSize) + LocalKnownZero.countTrailingOnes())); } } - KnownZero = APInt::getLowBitsSet(BitWidth, TrailZ) & Mask; + KnownZero = APInt::getLowBitsSet(BitWidth, TrailZ); break; } case Instruction::PHI: { @@ -688,17 +672,13 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, break; // Ok, we have a PHI of the form L op= R. Check for low // zero bits. - APInt Mask2 = APInt::getAllOnesValue(BitWidth); - ComputeMaskedBits(R, Mask2, KnownZero2, KnownOne2, TD, Depth+1); - Mask2 = APInt::getLowBitsSet(BitWidth, - KnownZero2.countTrailingOnes()); + ComputeMaskedBits(R, KnownZero2, KnownOne2, TD, Depth+1); // We need to take the minimum number of known bits APInt KnownZero3(KnownZero), KnownOne3(KnownOne); - ComputeMaskedBits(L, Mask2, KnownZero3, KnownOne3, TD, Depth+1); + ComputeMaskedBits(L, KnownZero3, KnownOne3, TD, Depth+1); - KnownZero = Mask & - APInt::getLowBitsSet(BitWidth, + KnownZero = APInt::getLowBitsSet(BitWidth, std::min(KnownZero2.countTrailingOnes(), KnownZero3.countTrailingOnes())); break; @@ -717,8 +697,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, if (P->hasConstantValue() == P) break; - KnownZero = Mask; - KnownOne = Mask; + KnownZero = APInt::getAllOnesValue(BitWidth); + KnownOne = APInt::getAllOnesValue(BitWidth); for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i) { // Skip direct self references. if (P->getIncomingValue(i) == P) continue; @@ -727,8 +707,8 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, KnownOne2 = APInt(BitWidth, 0); // Recurse, but cap the recursion to one level, because we don't // want to waste time spinning around in loops. - ComputeMaskedBits(P->getIncomingValue(i), KnownZero | KnownOne, - KnownZero2, KnownOne2, TD, MaxDepth-1); + ComputeMaskedBits(P->getIncomingValue(i), KnownZero2, KnownOne2, TD, + MaxDepth-1); KnownZero &= KnownZero2; KnownOne &= KnownOne2; // If all bits have been ruled out, there's no need to check @@ -749,17 +729,17 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, // If this call is undefined for 0, the result will be less than 2^n. if (II->getArgOperand(1) == ConstantInt::getTrue(II->getContext())) LowBits -= 1; - KnownZero = Mask & APInt::getHighBitsSet(BitWidth, BitWidth - LowBits); + KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - LowBits); break; } case Intrinsic::ctpop: { unsigned LowBits = Log2_32(BitWidth)+1; - KnownZero = Mask & APInt::getHighBitsSet(BitWidth, BitWidth - LowBits); + KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - LowBits); break; } case Intrinsic::x86_sse42_crc32_64_8: case Intrinsic::x86_sse42_crc32_64_64: - KnownZero = Mask & APInt::getHighBitsSet(64, 32); + KnownZero = APInt::getHighBitsSet(64, 32); break; } } @@ -774,21 +754,19 @@ void llvm::ComputeMaskedBits(Value *V, const APInt &Mask, case Intrinsic::uadd_with_overflow: case Intrinsic::sadd_with_overflow: ComputeMaskedBitsAddSub(true, II->getArgOperand(0), - II->getArgOperand(1), false, Mask, - KnownZero, KnownOne, KnownZero2, KnownOne2, - TD, Depth); + II->getArgOperand(1), false, KnownZero, + KnownOne, KnownZero2, KnownOne2, TD, Depth); break; case Intrinsic::usub_with_overflow: case Intrinsic::ssub_with_overflow: ComputeMaskedBitsAddSub(false, II->getArgOperand(0), - II->getArgOperand(1), false, Mask, - KnownZero, KnownOne, KnownZero2, KnownOne2, - TD, Depth); + II->getArgOperand(1), false, KnownZero, + KnownOne, KnownZero2, KnownOne2, TD, Depth); break; case Intrinsic::umul_with_overflow: case Intrinsic::smul_with_overflow: ComputeMaskedBitsMul(II->getArgOperand(0), II->getArgOperand(1), - false, Mask, KnownZero, KnownOne, + false, KnownZero, KnownOne, KnownZero2, KnownOne2, TD, Depth); break; } @@ -809,8 +787,7 @@ void llvm::ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne, } APInt ZeroBits(BitWidth, 0); APInt OneBits(BitWidth, 0); - ComputeMaskedBits(V, APInt::getSignBit(BitWidth), ZeroBits, OneBits, TD, - Depth); + ComputeMaskedBits(V, ZeroBits, OneBits, TD, Depth); KnownOne = OneBits[BitWidth - 1]; KnownZero = ZeroBits[BitWidth - 1]; } @@ -918,7 +895,7 @@ bool llvm::isKnownNonZero(Value *V, const TargetData *TD, unsigned Depth) { APInt KnownZero(BitWidth, 0); APInt KnownOne(BitWidth, 0); - ComputeMaskedBits(X, APInt(BitWidth, 1), KnownZero, KnownOne, TD, Depth); + ComputeMaskedBits(X, KnownZero, KnownOne, TD, Depth); if (KnownOne[0]) return true; } @@ -960,12 +937,12 @@ bool llvm::isKnownNonZero(Value *V, const TargetData *TD, unsigned Depth) { APInt Mask = APInt::getSignedMaxValue(BitWidth); // The sign bit of X is set. If some other bit is set then X is not equal // to INT_MIN. - ComputeMaskedBits(X, Mask, KnownZero, KnownOne, TD, Depth); + ComputeMaskedBits(X, KnownZero, KnownOne, TD, Depth); if ((KnownOne & Mask) != 0) return true; // The sign bit of Y is set. If some other bit is set then Y is not equal // to INT_MIN. - ComputeMaskedBits(Y, Mask, KnownZero, KnownOne, TD, Depth); + ComputeMaskedBits(Y, KnownZero, KnownOne, TD, Depth); if ((KnownOne & Mask) != 0) return true; } @@ -995,8 +972,7 @@ bool llvm::isKnownNonZero(Value *V, const TargetData *TD, unsigned Depth) { if (!BitWidth) return false; APInt KnownZero(BitWidth, 0); APInt KnownOne(BitWidth, 0); - ComputeMaskedBits(V, APInt::getAllOnesValue(BitWidth), KnownZero, KnownOne, - TD, Depth); + ComputeMaskedBits(V, KnownZero, KnownOne, TD, Depth); return KnownOne != 0; } @@ -1012,7 +988,7 @@ bool llvm::isKnownNonZero(Value *V, const TargetData *TD, unsigned Depth) { bool llvm::MaskedValueIsZero(Value *V, const APInt &Mask, const TargetData *TD, unsigned Depth) { APInt KnownZero(Mask.getBitWidth(), 0), KnownOne(Mask.getBitWidth(), 0); - ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD, Depth); + ComputeMaskedBits(V, KnownZero, KnownOne, TD, Depth); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); return (KnownZero & Mask) == Mask; } @@ -1103,13 +1079,11 @@ unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD, if (ConstantInt *CRHS = dyn_cast<ConstantInt>(U->getOperand(1))) if (CRHS->isAllOnesValue()) { APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0); - APInt Mask = APInt::getAllOnesValue(TyBits); - ComputeMaskedBits(U->getOperand(0), Mask, KnownZero, KnownOne, TD, - Depth+1); + ComputeMaskedBits(U->getOperand(0), KnownZero, KnownOne, TD, Depth+1); // If the input is known to be 0 or 1, the output is 0/-1, which is all // sign bits set. - if ((KnownZero | APInt(TyBits, 1)) == Mask) + if ((KnownZero | APInt(TyBits, 1)).isAllOnesValue()) return TyBits; // If we are subtracting one from a positive number, there is no carry @@ -1130,12 +1104,10 @@ unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD, if (ConstantInt *CLHS = dyn_cast<ConstantInt>(U->getOperand(0))) if (CLHS->isNullValue()) { APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0); - APInt Mask = APInt::getAllOnesValue(TyBits); - ComputeMaskedBits(U->getOperand(1), Mask, KnownZero, KnownOne, - TD, Depth+1); + ComputeMaskedBits(U->getOperand(1), KnownZero, KnownOne, TD, Depth+1); // If the input is known to be 0 or 1, the output is 0/-1, which is all // sign bits set. - if ((KnownZero | APInt(TyBits, 1)) == Mask) + if ((KnownZero | APInt(TyBits, 1)).isAllOnesValue()) return TyBits; // If the input is known to be positive (the sign bit is known clear), @@ -1177,8 +1149,8 @@ unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD, // Finally, if we can prove that the top bits of the result are 0's or 1's, // use this information. APInt KnownZero(TyBits, 0), KnownOne(TyBits, 0); - APInt Mask = APInt::getAllOnesValue(TyBits); - ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD, Depth); + APInt Mask; + ComputeMaskedBits(V, KnownZero, KnownOne, TD, Depth); if (KnownZero.isNegative()) { // sign bit is 0 Mask = KnownZero; @@ -1870,8 +1842,7 @@ bool llvm::isSafeToSpeculativelyExecute(const Value *V, return false; APInt KnownZero(BitWidth, 0); APInt KnownOne(BitWidth, 0); - ComputeMaskedBits(Op, APInt::getAllOnesValue(BitWidth), - KnownZero, KnownOne, TD); + ComputeMaskedBits(Op, KnownZero, KnownOne, TD); return !!KnownZero; } case Instruction::Load: { @@ -1883,6 +1854,14 @@ bool llvm::isSafeToSpeculativelyExecute(const Value *V, case Instruction::Call: { if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { switch (II->getIntrinsicID()) { + // These synthetic intrinsics have no side-effects, and just mark + // information about their operands. + // FIXME: There are other no-op synthetic instructions that potentially + // should be considered at least *safe* to speculate... + case Intrinsic::dbg_declare: + case Intrinsic::dbg_value: + return true; + case Intrinsic::bswap: case Intrinsic::ctlz: case Intrinsic::ctpop: |