X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLazyValueInfo.cpp;h=c712c9f487d1260c01f5f1a62369e5745cd0fce5;hb=0f06462959bcf8224e72b7c739659292dddbdc87;hp=6e275978276d2b4910fda7776f2e037126caa9e6;hpb=69388e5a4a941e7e02c7f4b52d6e743a480e135f;p=oota-llvm.git diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp index 6e275978276..c712c9f487d 100644 --- a/lib/Analysis/LazyValueInfo.cpp +++ b/lib/Analysis/LazyValueInfo.cpp @@ -12,28 +12,37 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "lazy-value-info" #include "llvm/Analysis/LazyValueInfo.h" -#include "llvm/Analysis/ValueTracking.h" -#include "llvm/Constants.h" -#include "llvm/Instructions.h" -#include "llvm/IntrinsicInst.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/Analysis/AssumptionTracker.h" #include "llvm/Analysis/ConstantFolding.h" -#include "llvm/Target/TargetData.h" -#include "llvm/Support/CFG.h" -#include "llvm/Support/ConstantRange.h" +#include "llvm/Analysis/ValueTracking.h" +#include "llvm/IR/CFG.h" +#include "llvm/IR/ConstantRange.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Dominators.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/PatternMatch.h" +#include "llvm/IR/ValueHandle.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/Support/ValueHandle.h" -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/DenseSet.h" -#include "llvm/ADT/STLExtras.h" +#include "llvm/Target/TargetLibraryInfo.h" #include #include using namespace llvm; +using namespace PatternMatch; + +#define DEBUG_TYPE "lazy-value-info" char LazyValueInfo::ID = 0; -INITIALIZE_PASS(LazyValueInfo, "lazy-value-info", +INITIALIZE_PASS_BEGIN(LazyValueInfo, "lazy-value-info", + "Lazy Value Information Analysis", false, true) +INITIALIZE_PASS_DEPENDENCY(AssumptionTracker) +INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo) +INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info", "Lazy Value Information Analysis", false, true) namespace llvm { @@ -61,10 +70,10 @@ class LVILatticeVal { constant, /// notconstant - This Value is known to not have the specified value. notconstant, - + /// constantrange - The Value falls within this range. constantrange, - + /// overdefined - This value is not known to be constant, and we know that /// it has a value. overdefined @@ -77,7 +86,7 @@ class LVILatticeVal { ConstantRange Range; public: - LVILatticeVal() : Tag(undefined), Val(0), Range(1, true) {} + LVILatticeVal() : Tag(undefined), Val(nullptr), Range(1, true) {} static LVILatticeVal get(Constant *C) { LVILatticeVal Res; @@ -167,7 +176,7 @@ public: if (NewR.isEmptySet()) return markOverdefined(); - bool changed = Range == NewR; + bool changed = Range != NewR; Range = NewR; return changed; } @@ -207,7 +216,7 @@ public: // Unless we can prove that the two Constants are different, we must // move to overdefined. - // FIXME: use TargetData for smarter constant folding. + // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding. if (ConstantInt *Res = dyn_cast( ConstantFoldCompareInstOperands(CmpInst::ICMP_NE, getConstant(), @@ -233,7 +242,7 @@ public: // Unless we can prove that the two Constants are different, we must // move to overdefined. - // FIXME: use TargetData for smarter constant folding. + // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding. if (ConstantInt *Res = dyn_cast( ConstantFoldCompareInstOperands(CmpInst::ICMP_NE, getNotConstant(), @@ -289,7 +298,7 @@ raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) { //===----------------------------------------------------------------------===// namespace { - /// LVIValueHandle - A callback value handle update the cache when + /// LVIValueHandle - A callback value handle updates the cache when /// values are erased. class LazyValueInfoCache; struct LVIValueHandle : public CallbackVH { @@ -297,54 +306,10 @@ namespace { LVIValueHandle(Value *V, LazyValueInfoCache *P) : CallbackVH(V), Parent(P) { } - - void deleted(); - void allUsesReplacedWith(Value *V) { - deleted(); - } - }; -} -namespace llvm { - template<> - struct DenseMapInfo { - typedef DenseMapInfo PointerInfo; - static inline LVIValueHandle getEmptyKey() { - return LVIValueHandle(PointerInfo::getEmptyKey(), - static_cast(0)); - } - static inline LVIValueHandle getTombstoneKey() { - return LVIValueHandle(PointerInfo::getTombstoneKey(), - static_cast(0)); - } - static unsigned getHashValue(const LVIValueHandle &Val) { - return PointerInfo::getHashValue(Val); - } - static bool isEqual(const LVIValueHandle &LHS, const LVIValueHandle &RHS) { - return LHS == RHS; - } - }; - - template<> - struct DenseMapInfo, Value*> > { - typedef std::pair, Value*> PairTy; - typedef DenseMapInfo > APointerInfo; - typedef DenseMapInfo BPointerInfo; - static inline PairTy getEmptyKey() { - return std::make_pair(APointerInfo::getEmptyKey(), - BPointerInfo::getEmptyKey()); - } - static inline PairTy getTombstoneKey() { - return std::make_pair(APointerInfo::getTombstoneKey(), - BPointerInfo::getTombstoneKey()); - } - static unsigned getHashValue( const PairTy &Val) { - return APointerInfo::getHashValue(Val.first) ^ - BPointerInfo::getHashValue(Val.second); - } - static bool isEqual(const PairTy &LHS, const PairTy &RHS) { - return APointerInfo::isEqual(LHS.first, RHS.first) && - BPointerInfo::isEqual(LHS.second, RHS.second); + void deleted() override; + void allUsesReplacedWith(Value *V) override { + deleted(); } }; } @@ -360,18 +325,29 @@ namespace { /// ValueCache - This is all of the cached information for all values, /// mapped from Value* to key information. - DenseMap ValueCache; + std::map ValueCache; /// OverDefinedCache - This tracks, on a per-block basis, the set of /// values that are over-defined at the end of that block. This is required /// for cache updating. typedef std::pair, Value*> OverDefinedPairTy; DenseSet OverDefinedCache; - + + /// SeenBlocks - Keep track of all blocks that we have ever seen, so we + /// don't spend time removing unused blocks from our caches. + DenseSet > SeenBlocks; + /// BlockValueStack - This stack holds the state of the value solver /// during a query. It basically emulates the callstack of the naive /// recursive value lookup process. std::stack > BlockValueStack; + + /// A pointer to the cache of @llvm.assume calls. + AssumptionTracker *AT; + /// An optional DL pointer. + const DataLayout *DL; + /// An optional DT pointer. + DominatorTree *DT; friend struct LVIValueHandle; @@ -398,7 +374,8 @@ namespace { LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB); bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T, - LVILatticeVal &Result); + LVILatticeVal &Result, + Instruction *CxtI = nullptr); bool hasBlockValue(Value *Val, BasicBlock *BB); // These methods process one work item and may add more. A false value @@ -411,6 +388,8 @@ namespace { PHINode *PN, BasicBlock *BB); bool solveBlockValueConstantRange(LVILatticeVal &BBLV, Instruction *BBI, BasicBlock *BB); + void mergeAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV, + Instruction *BBI); void solve(); @@ -421,11 +400,18 @@ namespace { public: /// getValueInBlock - This is the query interface to determine the lattice /// value for the specified Value* at the end of the specified block. - LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB); + LVILatticeVal getValueInBlock(Value *V, BasicBlock *BB, + Instruction *CxtI = nullptr); + + /// getValueAt - This is the query interface to determine the lattice + /// value for the specified Value* at the specified instruction (generally + /// from an assume intrinsic). + LVILatticeVal getValueAt(Value *V, Instruction *CxtI); /// getValueOnEdge - This is the query interface to determine the lattice /// value for the specified Value* that is true on the specified edge. - LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB); + LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB, + Instruction *CxtI = nullptr); /// threadEdge - This is the update interface to inform the cache that an /// edge from PredBB to OldSucc has been threaded to be from PredBB to @@ -438,9 +424,14 @@ namespace { /// clear - Empty the cache. void clear() { + SeenBlocks.clear(); ValueCache.clear(); OverDefinedCache.clear(); } + + LazyValueInfoCache(AssumptionTracker *AT, + const DataLayout *DL = nullptr, + DominatorTree *DT = nullptr) : AT(AT), DL(DL), DT(DT) {} }; } // end anonymous namespace @@ -455,8 +446,8 @@ void LVIValueHandle::deleted() { if (I->second == getValPtr()) ToErase.push_back(*I); } - - for (SmallVector::iterator I = ToErase.begin(), + + for (SmallVectorImpl::iterator I = ToErase.begin(), E = ToErase.end(); I != E; ++I) Parent->OverDefinedCache.erase(*I); @@ -466,18 +457,24 @@ void LVIValueHandle::deleted() { } void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { + // Shortcut if we have never seen this block. + DenseSet >::iterator I = SeenBlocks.find(BB); + if (I == SeenBlocks.end()) + return; + SeenBlocks.erase(I); + SmallVector ToErase; for (DenseSet::iterator I = OverDefinedCache.begin(), E = OverDefinedCache.end(); I != E; ++I) { if (I->first == BB) ToErase.push_back(*I); } - - for (SmallVector::iterator I = ToErase.begin(), + + for (SmallVectorImpl::iterator I = ToErase.begin(), E = ToErase.end(); I != E; ++I) OverDefinedCache.erase(*I); - for (DenseMap::iterator + for (std::map::iterator I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I) I->second.erase(BB); } @@ -485,8 +482,10 @@ void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { void LazyValueInfoCache::solve() { while (!BlockValueStack.empty()) { std::pair &e = BlockValueStack.top(); - if (solveBlockValue(e.second, e.first)) + if (solveBlockValue(e.second, e.first)) { + assert(BlockValueStack.top() == e); BlockValueStack.pop(); + } } } @@ -496,8 +495,10 @@ bool LazyValueInfoCache::hasBlockValue(Value *Val, BasicBlock *BB) { return true; LVIValueHandle ValHandle(Val, this); - if (!ValueCache.count(ValHandle)) return false; - return ValueCache[ValHandle].count(BB); + std::map::iterator I = + ValueCache.find(ValHandle); + if (I == ValueCache.end()) return false; + return I->second.count(BB); } LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) { @@ -505,6 +506,7 @@ LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) { if (Constant *VC = dyn_cast(Val)) return LVILatticeVal::get(VC); + SeenBlocks.insert(BB); return lookup(Val)[BB]; } @@ -513,6 +515,7 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { return true; ValueCacheEntryTy &Cache = lookup(Val); + SeenBlocks.insert(BB); LVILatticeVal &BBLV = Cache[BB]; // OverDefinedCacheUpdater is a helper object that will update @@ -521,7 +524,6 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { // cache needs updating, i.e. if we have solve a new value or not. OverDefinedCacheUpdater ODCacheUpdater(Val, BB, BBLV, this); - // If we've already computed this block's value, return it. if (!BBLV.isUndefined()) { DEBUG(dbgs() << " reuse BB '" << BB->getName() << "' val=" << BBLV <<'\n'); @@ -538,7 +540,7 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { BBLV.markOverdefined(); Instruction *BBI = dyn_cast(Val); - if (BBI == 0 || BBI->getParent() != BB) { + if (!BBI || BBI->getParent() != BB) { return ODCacheUpdater.markResult(solveBlockValueNonLocal(BBLV, Val, BB)); } @@ -579,13 +581,11 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) { if (LoadInst *L = dyn_cast(I)) { return L->getPointerAddressSpace() == 0 && - GetUnderlyingObject(L->getPointerOperand()) == - GetUnderlyingObject(Ptr); + GetUnderlyingObject(L->getPointerOperand()) == Ptr; } if (StoreInst *S = dyn_cast(I)) { return S->getPointerAddressSpace() == 0 && - GetUnderlyingObject(S->getPointerOperand()) == - GetUnderlyingObject(Ptr); + GetUnderlyingObject(S->getPointerOperand()) == Ptr; } if (MemIntrinsic *MI = dyn_cast(I)) { if (MI->isVolatile()) return false; @@ -595,11 +595,11 @@ static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) { if (!Len || Len->isZero()) return false; if (MI->getDestAddressSpace() == 0) - if (MI->getRawDest() == Ptr || MI->getDest() == Ptr) + if (GetUnderlyingObject(MI->getRawDest()) == Ptr) return true; if (MemTransferInst *MTI = dyn_cast(MI)) if (MTI->getSourceAddressSpace() == 0) - if (MTI->getRawSource() == Ptr || MTI->getSource() == Ptr) + if (GetUnderlyingObject(MTI->getRawSource()) == Ptr) return true; } return false; @@ -613,13 +613,19 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, // then we know that the pointer can't be NULL. bool NotNull = false; if (Val->getType()->isPointerTy()) { - if (isa(Val)) { + if (isKnownNonNull(Val)) { NotNull = true; } else { - for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();BI != BE;++BI){ - if (InstructionDereferencesPointer(BI, Val)) { - NotNull = true; - break; + Value *UnderlyingVal = GetUnderlyingObject(Val); + // If 'GetUnderlyingObject' didn't converge, skip it. It won't converge + // inside InstructionDereferencesPointer either. + if (UnderlyingVal == GetUnderlyingObject(UnderlyingVal, nullptr, 1)) { + for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); + BI != BE; ++BI) { + if (InstructionDereferencesPointer(BI, UnderlyingVal)) { + NotNull = true; + break; + } } } } @@ -630,7 +636,7 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, if (BB == &BB->getParent()->getEntryBlock()) { assert(isa(Val) && "Unknown live-in to the entry block"); if (NotNull) { - const PointerType *PTy = cast(Val->getType()); + PointerType *PTy = cast(Val->getType()); Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy)); } else { Result.markOverdefined(); @@ -658,7 +664,7 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, // If we previously determined that this is a pointer that can't be null // then return that rather than giving up entirely. if (NotNull) { - const PointerType *PTy = cast(Val->getType()); + PointerType *PTy = cast(Val->getType()); Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy)); } @@ -686,7 +692,10 @@ bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV, BasicBlock *PhiBB = PN->getIncomingBlock(i); Value *PhiVal = PN->getIncomingValue(i); LVILatticeVal EdgeResult; - EdgesMissing |= !getEdgeValue(PhiVal, PhiBB, BB, EdgeResult); + // Note that we can provide PN as the context value to getEdgeValue, even + // though the results will be cached, because PN is the value being used as + // the cache key in the caller. + EdgesMissing |= !getEdgeValue(PhiVal, PhiBB, BB, EdgeResult, PN); if (EdgesMissing) continue; @@ -711,6 +720,36 @@ bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV, return true; } +static bool getValueFromFromCondition(Value *Val, ICmpInst *ICI, + LVILatticeVal &Result, + bool isTrueDest = true); + +// If we can determine a constant range for the value Val at the context +// provided by the instruction BBI, then merge it into BBLV. If we did find a +// constant range, return true. +void LazyValueInfoCache::mergeAssumeBlockValueConstantRange( + Value *Val, LVILatticeVal &BBLV, Instruction *BBI) { + BBI = BBI ? BBI : dyn_cast(Val); + if (!BBI) + return; + + for (auto &I : AT->assumptions(BBI->getParent()->getParent())) { + if (!isValidAssumeForContext(I, BBI, DL, DT)) + continue; + + Value *C = I->getArgOperand(0); + if (ICmpInst *ICI = dyn_cast(C)) { + LVILatticeVal Result; + if (getValueFromFromCondition(Val, ICI, Result)) { + if (BBLV.isOverdefined()) + BBLV = Result; + else + BBLV.mergeIn(Result); + } + } + } +} + bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, Instruction *BBI, BasicBlock *BB) { @@ -721,6 +760,7 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, } LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB); + mergeAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI); if (!LHSVal.isConstantRange()) { BBLV.markOverdefined(); return true; @@ -728,7 +768,7 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, ConstantRange LHSRange = LHSVal.getConstantRange(); ConstantRange RHSRange(1); - const IntegerType *ResultTy = cast(BBI->getType()); + IntegerType *ResultTy = cast(BBI->getType()); if (isa(BBI)) { if (ConstantInt *RHS = dyn_cast(BBI->getOperand(1))) { RHSRange = ConstantRange(RHS->getValue()); @@ -792,15 +832,51 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, return true; } -/// getEdgeValue - This method attempts to infer more complex -bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, - BasicBlock *BBTo, LVILatticeVal &Result) { - // If already a constant, there is nothing to compute. - if (Constant *VC = dyn_cast(Val)) { - Result = LVILatticeVal::get(VC); - return true; +bool getValueFromFromCondition(Value *Val, ICmpInst *ICI, + LVILatticeVal &Result, bool isTrueDest) { + if (ICI && isa(ICI->getOperand(1))) { + if (ICI->isEquality() && ICI->getOperand(0) == Val) { + // We know that V has the RHS constant if this is a true SETEQ or + // false SETNE. + if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ)) + Result = LVILatticeVal::get(cast(ICI->getOperand(1))); + else + Result = LVILatticeVal::getNot(cast(ICI->getOperand(1))); + return true; + } + + // Recognize the range checking idiom that InstCombine produces. + // (X-C1) u< C2 --> [C1, C1+C2) + ConstantInt *NegOffset = nullptr; + if (ICI->getPredicate() == ICmpInst::ICMP_ULT) + match(ICI->getOperand(0), m_Add(m_Specific(Val), + m_ConstantInt(NegOffset))); + + ConstantInt *CI = dyn_cast(ICI->getOperand(1)); + if (CI && (ICI->getOperand(0) == Val || NegOffset)) { + // Calculate the range of values that would satisfy the comparison. + ConstantRange CmpRange(CI->getValue()); + ConstantRange TrueValues = + ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange); + + if (NegOffset) // Apply the offset from above. + TrueValues = TrueValues.subtract(NegOffset->getValue()); + + // If we're interested in the false dest, invert the condition. + if (!isTrueDest) TrueValues = TrueValues.inverse(); + + Result = LVILatticeVal::getRange(TrueValues); + return true; + } } - + + return false; +} + +/// \brief Compute the value of Val on the edge BBFrom -> BBTo. Returns false if +/// Val is not constrained on the edge. +static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom, + BasicBlock *BBTo, LVILatticeVal &Result) { // TODO: Handle more complex conditionals. If (v == 0 || v2 < 1) is false, we // know that v != 0. if (BranchInst *BI = dyn_cast(BBFrom->getTerminator())) { @@ -823,108 +899,132 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, // If the condition of the branch is an equality comparison, we may be // able to infer the value. ICmpInst *ICI = dyn_cast(BI->getCondition()); - if (ICI && ICI->getOperand(0) == Val && - isa(ICI->getOperand(1))) { - if (ICI->isEquality()) { - // We know that V has the RHS constant if this is a true SETEQ or - // false SETNE. - if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ)) - Result = LVILatticeVal::get(cast(ICI->getOperand(1))); - else - Result = LVILatticeVal::getNot(cast(ICI->getOperand(1))); - return true; - } - - if (ConstantInt *CI = dyn_cast(ICI->getOperand(1))) { - // Calculate the range of values that would satisfy the comparison. - ConstantRange CmpRange(CI->getValue(), CI->getValue()+1); - ConstantRange TrueValues = - ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange); - - // If we're interested in the false dest, invert the condition. - if (!isTrueDest) TrueValues = TrueValues.inverse(); - - // Figure out the possible values of the query BEFORE this branch. - if (!hasBlockValue(Val, BBFrom)) { - BlockValueStack.push(std::make_pair(BBFrom, Val)); - return false; - } - - LVILatticeVal InBlock = getBlockValue(Val, BBFrom); - if (!InBlock.isConstantRange()) { - Result = LVILatticeVal::getRange(TrueValues); - return true; - } - - // Find all potential values that satisfy both the input and output - // conditions. - ConstantRange PossibleValues = - TrueValues.intersectWith(InBlock.getConstantRange()); - - Result = LVILatticeVal::getRange(PossibleValues); - return true; - } - } + if (getValueFromFromCondition(Val, ICI, Result, isTrueDest)) + return true; } } // If the edge was formed by a switch on the value, then we may know exactly // what it is. if (SwitchInst *SI = dyn_cast(BBFrom->getTerminator())) { - if (SI->getCondition() == Val) { - // We don't know anything in the default case. - if (SI->getDefaultDest() == BBTo) { - Result.markOverdefined(); - return true; - } - - // We only know something if there is exactly one value that goes from - // BBFrom to BBTo. - unsigned NumEdges = 0; - ConstantInt *EdgeVal = 0; - for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) { - if (SI->getSuccessor(i) != BBTo) continue; - if (NumEdges++) break; - EdgeVal = SI->getCaseValue(i); - } - assert(EdgeVal && "Missing successor?"); - if (NumEdges == 1) { - Result = LVILatticeVal::get(EdgeVal); - return true; - } + if (SI->getCondition() != Val) + return false; + + bool DefaultCase = SI->getDefaultDest() == BBTo; + unsigned BitWidth = Val->getType()->getIntegerBitWidth(); + ConstantRange EdgesVals(BitWidth, DefaultCase/*isFullSet*/); + + for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); + i != e; ++i) { + ConstantRange EdgeVal(i.getCaseValue()->getValue()); + if (DefaultCase) { + // It is possible that the default destination is the destination of + // some cases. There is no need to perform difference for those cases. + if (i.getCaseSuccessor() != BBTo) + EdgesVals = EdgesVals.difference(EdgeVal); + } else if (i.getCaseSuccessor() == BBTo) + EdgesVals = EdgesVals.unionWith(EdgeVal); } - } - - // Otherwise see if the value is known in the block. - if (hasBlockValue(Val, BBFrom)) { - Result = getBlockValue(Val, BBFrom); + Result = LVILatticeVal::getRange(EdgesVals); return true; } - BlockValueStack.push(std::make_pair(BBFrom, Val)); return false; } -LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB) { +/// \brief Compute the value of Val on the edge BBFrom -> BBTo, or the value at +/// the basic block if the edge does not constraint Val. +bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, + BasicBlock *BBTo, LVILatticeVal &Result, + Instruction *CxtI) { + // If already a constant, there is nothing to compute. + if (Constant *VC = dyn_cast(Val)) { + Result = LVILatticeVal::get(VC); + return true; + } + + if (getEdgeValueLocal(Val, BBFrom, BBTo, Result)) { + if (!Result.isConstantRange() || + Result.getConstantRange().getSingleElement()) + return true; + + // FIXME: this check should be moved to the beginning of the function when + // LVI better supports recursive values. Even for the single value case, we + // can intersect to detect dead code (an empty range). + if (!hasBlockValue(Val, BBFrom)) { + BlockValueStack.push(std::make_pair(BBFrom, Val)); + return false; + } + + // Try to intersect ranges of the BB and the constraint on the edge. + LVILatticeVal InBlock = getBlockValue(Val, BBFrom); + mergeAssumeBlockValueConstantRange(Val, InBlock, BBFrom->getTerminator()); + // See note on the use of the CxtI with mergeAssumeBlockValueConstantRange, + // and caching, below. + mergeAssumeBlockValueConstantRange(Val, InBlock, CxtI); + if (!InBlock.isConstantRange()) + return true; + + ConstantRange Range = + Result.getConstantRange().intersectWith(InBlock.getConstantRange()); + Result = LVILatticeVal::getRange(Range); + return true; + } + + if (!hasBlockValue(Val, BBFrom)) { + BlockValueStack.push(std::make_pair(BBFrom, Val)); + return false; + } + + // if we couldn't compute the value on the edge, use the value from the BB + Result = getBlockValue(Val, BBFrom); + mergeAssumeBlockValueConstantRange(Val, Result, BBFrom->getTerminator()); + // We can use the context instruction (generically the ultimate instruction + // the calling pass is trying to simplify) here, even though the result of + // this function is generally cached when called from the solve* functions + // (and that cached result might be used with queries using a different + // context instruction), because when this function is called from the solve* + // functions, the context instruction is not provided. When called from + // LazyValueInfoCache::getValueOnEdge, the context instruction is provided, + // but then the result is not cached. + mergeAssumeBlockValueConstantRange(Val, Result, CxtI); + return true; +} + +LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB, + Instruction *CxtI) { DEBUG(dbgs() << "LVI Getting block end value " << *V << " at '" << BB->getName() << "'\n"); BlockValueStack.push(std::make_pair(BB, V)); solve(); LVILatticeVal Result = getBlockValue(V, BB); + mergeAssumeBlockValueConstantRange(V, Result, CxtI); + + DEBUG(dbgs() << " Result = " << Result << "\n"); + return Result; +} + +LVILatticeVal LazyValueInfoCache::getValueAt(Value *V, Instruction *CxtI) { + DEBUG(dbgs() << "LVI Getting value " << *V << " at '" + << CxtI->getName() << "'\n"); + + LVILatticeVal Result; + mergeAssumeBlockValueConstantRange(V, Result, CxtI); DEBUG(dbgs() << " Result = " << Result << "\n"); return Result; } LVILatticeVal LazyValueInfoCache:: -getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB) { +getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB, + Instruction *CxtI) { DEBUG(dbgs() << "LVI Getting edge value " << *V << " from '" << FromBB->getName() << "' to '" << ToBB->getName() << "'\n"); LVILatticeVal Result; - if (!getEdgeValue(V, FromBB, ToBB, Result)) { + if (!getEdgeValue(V, FromBB, ToBB, Result, CxtI)) { solve(); - bool WasFastQuery = getEdgeValue(V, FromBB, ToBB, Result); + bool WasFastQuery = getEdgeValue(V, FromBB, ToBB, Result, CxtI); (void)WasFastQuery; assert(WasFastQuery && "More work to do after problem solved?"); } @@ -998,31 +1098,51 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, //===----------------------------------------------------------------------===// /// getCache - This lazily constructs the LazyValueInfoCache. -static LazyValueInfoCache &getCache(void *&PImpl) { +static LazyValueInfoCache &getCache(void *&PImpl, + AssumptionTracker *AT, + const DataLayout *DL = nullptr, + DominatorTree *DT = nullptr) { if (!PImpl) - PImpl = new LazyValueInfoCache(); + PImpl = new LazyValueInfoCache(AT, DL, DT); return *static_cast(PImpl); } bool LazyValueInfo::runOnFunction(Function &F) { + AT = &getAnalysis(); + + DominatorTreeWrapperPass *DTWP = + getAnalysisIfAvailable(); + DT = DTWP ? &DTWP->getDomTree() : nullptr; + + DataLayoutPass *DLP = getAnalysisIfAvailable(); + DL = DLP ? &DLP->getDataLayout() : nullptr; + TLI = &getAnalysis(); + if (PImpl) - getCache(PImpl).clear(); - - TD = getAnalysisIfAvailable(); + getCache(PImpl, AT, DL, DT).clear(); + // Fully lazy. return false; } +void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); + AU.addRequired(); +} + void LazyValueInfo::releaseMemory() { // If the cache was allocated, free it. if (PImpl) { - delete &getCache(PImpl); - PImpl = 0; + delete &getCache(PImpl, AT); + PImpl = nullptr; } } -Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) { - LVILatticeVal Result = getCache(PImpl).getValueInBlock(V, BB); +Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB, + Instruction *CxtI) { + LVILatticeVal Result = + getCache(PImpl, AT, DL, DT).getValueInBlock(V, BB, CxtI); if (Result.isConstant()) return Result.getConstant(); @@ -1031,14 +1151,16 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) { if (const APInt *SingleVal = CR.getSingleElement()) return ConstantInt::get(V->getContext(), *SingleVal); } - return 0; + return nullptr; } /// getConstantOnEdge - Determine whether the specified value is known to be a /// constant on the specified edge. Return null if not. Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB, - BasicBlock *ToBB) { - LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB); + BasicBlock *ToBB, + Instruction *CxtI) { + LVILatticeVal Result = + getCache(PImpl, AT, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI); if (Result.isConstant()) return Result.getConstant(); @@ -1047,53 +1169,50 @@ Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB, if (const APInt *SingleVal = CR.getSingleElement()) return ConstantInt::get(V->getContext(), *SingleVal); } - return 0; + return nullptr; } -/// getPredicateOnEdge - Determine whether the specified value comparison -/// with a constant is known to be true or false on the specified CFG edge. -/// Pred is a CmpInst predicate. -LazyValueInfo::Tristate -LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, - BasicBlock *FromBB, BasicBlock *ToBB) { - LVILatticeVal Result = getCache(PImpl).getValueOnEdge(V, FromBB, ToBB); - +static LazyValueInfo::Tristate +getPredicateResult(unsigned Pred, Constant *C, LVILatticeVal &Result, + const DataLayout *DL, TargetLibraryInfo *TLI) { + // If we know the value is a constant, evaluate the conditional. - Constant *Res = 0; + Constant *Res = nullptr; if (Result.isConstant()) { - Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, TD); + Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, DL, + TLI); if (ConstantInt *ResCI = dyn_cast(Res)) - return ResCI->isZero() ? False : True; - return Unknown; + return ResCI->isZero() ? LazyValueInfo::False : LazyValueInfo::True; + return LazyValueInfo::Unknown; } if (Result.isConstantRange()) { ConstantInt *CI = dyn_cast(C); - if (!CI) return Unknown; + if (!CI) return LazyValueInfo::Unknown; ConstantRange CR = Result.getConstantRange(); if (Pred == ICmpInst::ICMP_EQ) { if (!CR.contains(CI->getValue())) - return False; + return LazyValueInfo::False; if (CR.isSingleElement() && CR.contains(CI->getValue())) - return True; + return LazyValueInfo::True; } else if (Pred == ICmpInst::ICMP_NE) { if (!CR.contains(CI->getValue())) - return True; + return LazyValueInfo::True; if (CR.isSingleElement() && CR.contains(CI->getValue())) - return False; + return LazyValueInfo::False; } // Handle more complex predicates. ConstantRange TrueValues = ICmpInst::makeConstantRange((ICmpInst::Predicate)Pred, CI->getValue()); if (TrueValues.contains(CR)) - return True; + return LazyValueInfo::True; if (TrueValues.inverse().contains(CR)) - return False; - return Unknown; + return LazyValueInfo::False; + return LazyValueInfo::Unknown; } if (Result.isNotConstant()) { @@ -1102,27 +1221,51 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, if (Pred == ICmpInst::ICMP_EQ) { // !C1 == C -> false iff C1 == C. Res = ConstantFoldCompareInstOperands(ICmpInst::ICMP_NE, - Result.getNotConstant(), C, TD); + Result.getNotConstant(), C, DL, + TLI); if (Res->isNullValue()) - return False; + return LazyValueInfo::False; } else if (Pred == ICmpInst::ICMP_NE) { // !C1 != C -> true iff C1 == C. Res = ConstantFoldCompareInstOperands(ICmpInst::ICMP_NE, - Result.getNotConstant(), C, TD); + Result.getNotConstant(), C, DL, + TLI); if (Res->isNullValue()) - return True; + return LazyValueInfo::True; } - return Unknown; + return LazyValueInfo::Unknown; } - return Unknown; + return LazyValueInfo::Unknown; +} + +/// getPredicateOnEdge - Determine whether the specified value comparison +/// with a constant is known to be true or false on the specified CFG edge. +/// Pred is a CmpInst predicate. +LazyValueInfo::Tristate +LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, + BasicBlock *FromBB, BasicBlock *ToBB, + Instruction *CxtI) { + LVILatticeVal Result = + getCache(PImpl, AT, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI); + + return getPredicateResult(Pred, C, Result, DL, TLI); +} + +LazyValueInfo::Tristate +LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C, + Instruction *CxtI) { + LVILatticeVal Result = + getCache(PImpl, AT, DL, DT).getValueAt(V, CxtI); + + return getPredicateResult(Pred, C, Result, DL, TLI); } void LazyValueInfo::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, BasicBlock *NewSucc) { - if (PImpl) getCache(PImpl).threadEdge(PredBB, OldSucc, NewSucc); + if (PImpl) getCache(PImpl, AT, DL, DT).threadEdge(PredBB, OldSucc, NewSucc); } void LazyValueInfo::eraseBlock(BasicBlock *BB) { - if (PImpl) getCache(PImpl).eraseBlock(BB); + if (PImpl) getCache(PImpl, AT, DL, DT).eraseBlock(BB); }