X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLazyValueInfo.cpp;h=6f1137eab74dd94bde4a6c1c5dae818e38b01e56;hb=e8187e02949571e8a610644762b843ef2891f011;hp=121828fdf3de1f0dcdb177803b7b41e5f06fbbe8;hpb=87790abb08eea60a2fa090b6d7b498cc625fa3f2;p=oota-llvm.git diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp index 121828fdf3d..6f1137eab74 100644 --- a/lib/Analysis/LazyValueInfo.cpp +++ b/lib/Analysis/LazyValueInfo.cpp @@ -17,23 +17,28 @@ #include "llvm/Analysis/ValueTracking.h" #include "llvm/Constants.h" #include "llvm/Instructions.h" +#include "llvm/IntrinsicInst.h" #include "llvm/Analysis/ConstantFolding.h" #include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetLibraryInfo.h" #include "llvm/Support/CFG.h" #include "llvm/Support/ConstantRange.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/PatternMatch.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 -#include #include using namespace llvm; +using namespace PatternMatch; 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(TargetLibraryInfo) +INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info", "Lazy Value Information Analysis", false, true) namespace llvm { @@ -61,10 +66,10 @@ 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 @@ -207,7 +212,7 @@ 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 TargetData/TargetLibraryInfo for smarter constant folding. if (ConstantInt *Res = dyn_cast( ConstantFoldCompareInstOperands(CmpInst::ICMP_NE, getConstant(), @@ -233,7 +238,7 @@ 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 TargetData/TargetLibraryInfo for smarter constant folding. if (ConstantInt *Res = dyn_cast( ConstantFoldCompareInstOperands(CmpInst::ICMP_NE, getNotConstant(), @@ -267,6 +272,8 @@ public: } // end anonymous namespace. namespace llvm { +raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) + LLVM_ATTRIBUTE_USED; raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) { if (Val.isUndefined()) return OS << "undefined"; @@ -287,29 +294,51 @@ raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) { //===----------------------------------------------------------------------===// namespace { + /// LVIValueHandle - A callback value handle update the cache when + /// values are erased. + class LazyValueInfoCache; + struct LVIValueHandle : public CallbackVH { + LazyValueInfoCache *Parent; + + LVIValueHandle(Value *V, LazyValueInfoCache *P) + : CallbackVH(V), Parent(P) { } + + void deleted(); + void allUsesReplacedWith(Value *V) { + deleted(); + } + }; +} + +namespace { /// LazyValueInfoCache - This is the cache kept by LazyValueInfo which /// maintains information about queries across the clients' queries. class LazyValueInfoCache { - public: /// ValueCacheEntryTy - This is all of the cached block information for /// exactly one Value*. The entries are sorted by the BasicBlock* of the /// entries, allowing us to do a lookup with a binary search. typedef std::map, LVILatticeVal> ValueCacheEntryTy; - private: - /// LVIValueHandle - A callback value handle update the cache when - /// values are erased. - struct LVIValueHandle : public CallbackVH { - LazyValueInfoCache *Parent; - - LVIValueHandle(Value *V, LazyValueInfoCache *P) - : CallbackVH(V), Parent(P) { } - - void deleted(); - void allUsesReplacedWith(Value *V) { - deleted(); - } - }; + /// ValueCache - This is all of the cached information for all values, + /// mapped from Value* to key information. + 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; + + friend struct LVIValueHandle; /// OverDefinedCacheUpdater - A helper object that ensures that the /// OverDefinedCache is updated whenever solveBlockValue returns. @@ -329,15 +358,8 @@ namespace { return changed; } }; - - /// ValueCache - This is all of the cached information for all values, - /// mapped from Value* to key information. - 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. - std::set, Value*> > OverDefinedCache; + LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB); bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T, @@ -360,8 +382,6 @@ namespace { ValueCacheEntryTy &lookup(Value *V) { return ValueCache[LVIValueHandle(V, this)]; } - - std::stack > block_value_stack; public: /// getValueInBlock - This is the query interface to determine the lattice @@ -383,36 +403,51 @@ namespace { /// clear - Empty the cache. void clear() { + SeenBlocks.clear(); ValueCache.clear(); OverDefinedCache.clear(); } }; } // end anonymous namespace -void LazyValueInfoCache::LVIValueHandle::deleted() { - for (std::set, Value*> >::iterator +void LVIValueHandle::deleted() { + typedef std::pair, Value*> OverDefinedPairTy; + + SmallVector ToErase; + for (DenseSet::iterator I = Parent->OverDefinedCache.begin(), E = Parent->OverDefinedCache.end(); - I != E; ) { - std::set, Value*> >::iterator tmp = I; - ++I; - if (tmp->second == getValPtr()) - Parent->OverDefinedCache.erase(tmp); + I != E; ++I) { + if (I->second == getValPtr()) + ToErase.push_back(*I); } + for (SmallVector::iterator I = ToErase.begin(), + E = ToErase.end(); I != E; ++I) + Parent->OverDefinedCache.erase(*I); + // This erasure deallocates *this, so it MUST happen after we're done // using any and all members of *this. Parent->ValueCache.erase(*this); } void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { - for (std::set, Value*> >::iterator - I = OverDefinedCache.begin(), E = OverDefinedCache.end(); I != E; ) { - std::set, Value*> >::iterator tmp = I; - ++I; - if (tmp->first == BB) - OverDefinedCache.erase(tmp); + // 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(), + E = ToErase.end(); I != E; ++I) + OverDefinedCache.erase(*I); for (std::map::iterator I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I) @@ -420,10 +455,10 @@ void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { } void LazyValueInfoCache::solve() { - while (!block_value_stack.empty()) { - std::pair &e = block_value_stack.top(); + while (!BlockValueStack.empty()) { + std::pair &e = BlockValueStack.top(); if (solveBlockValue(e.second, e.first)) - block_value_stack.pop(); + BlockValueStack.pop(); } } @@ -432,7 +467,9 @@ bool LazyValueInfoCache::hasBlockValue(Value *Val, BasicBlock *BB) { if (isa(Val)) return true; - return lookup(Val).count(BB); + LVIValueHandle ValHandle(Val, this); + if (!ValueCache.count(ValHandle)) return false; + return ValueCache[ValHandle].count(BB); } LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) { @@ -440,6 +477,7 @@ LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) { if (Constant *VC = dyn_cast(Val)) return LVILatticeVal::get(VC); + SeenBlocks.insert(BB); return lookup(Val)[BB]; } @@ -448,6 +486,7 @@ 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 @@ -481,6 +520,11 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { return ODCacheUpdater.markResult(solveBlockValuePHINode(BBLV, PN, BB)); } + if (AllocaInst *AI = dyn_cast(BBI)) { + BBLV = LVILatticeVal::getNot(ConstantPointerNull::get(AI->getType())); + return ODCacheUpdater.markResult(true); + } + // We can only analyze the definitions of certain classes of instructions // (integral binops and casts at the moment), so bail if this isn't one. LVILatticeVal Result; @@ -517,7 +561,21 @@ static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) { GetUnderlyingObject(S->getPointerOperand()) == GetUnderlyingObject(Ptr); } - // FIXME: llvm.memset, etc. + if (MemIntrinsic *MI = dyn_cast(I)) { + if (MI->isVolatile()) return false; + + // FIXME: check whether it has a valuerange that excludes zero? + ConstantInt *Len = dyn_cast(MI->getLength()); + if (!Len || Len->isZero()) return false; + + if (MI->getDestAddressSpace() == 0) + if (MI->getRawDest() == Ptr || MI->getDest() == Ptr) + return true; + if (MemTransferInst *MTI = dyn_cast(MI)) + if (MTI->getSourceAddressSpace() == 0) + if (MTI->getRawSource() == Ptr || MTI->getSource() == Ptr) + return true; + } return false; } @@ -529,10 +587,14 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, // then we know that the pointer can't be NULL. bool NotNull = false; if (Val->getType()->isPointerTy()) { - for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();BI != BE;++BI){ - if (InstructionDereferencesPointer(BI, Val)) { - NotNull = true; - break; + if (isa(Val)) { + NotNull = true; + } else { + for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();BI != BE;++BI){ + if (InstructionDereferencesPointer(BI, Val)) { + NotNull = true; + break; + } } } } @@ -542,7 +604,7 @@ 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(); @@ -570,7 +632,7 @@ 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)); } @@ -628,7 +690,7 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, BasicBlock *BB) { // Figure out the range of the LHS. If that fails, bail. if (!hasBlockValue(BBI->getOperand(0), BB)) { - block_value_stack.push(std::make_pair(BB, BBI->getOperand(0))); + BlockValueStack.push(std::make_pair(BB, BBI->getOperand(0))); return false; } @@ -640,7 +702,7 @@ 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()); @@ -735,9 +797,8 @@ 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()) { + 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)) @@ -747,16 +808,32 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, return true; } - if (ConstantInt *CI = dyn_cast(ICI->getOperand(1))) { + // Recognize the range checking idiom that InstCombine produces. + // (X-C1) u< C2 --> [C1, C1+C2) + ConstantInt *NegOffset = 0; + 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(), CI->getValue()+1); 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(); // 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); @@ -789,10 +866,11 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, // 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; + for (SwitchInst::CaseIt i = SI->caseBegin(), e = SI->caseEnd(); + i != e; ++i) { + if (i.getCaseSuccessor() != BBTo) continue; if (NumEdges++) break; - EdgeVal = SI->getCaseValue(i); + EdgeVal = i.getCaseValue(); } assert(EdgeVal && "Missing successor?"); if (NumEdges == 1) { @@ -807,7 +885,7 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, Result = getBlockValue(Val, BBFrom); return true; } - block_value_stack.push(std::make_pair(BBFrom, Val)); + BlockValueStack.push(std::make_pair(BBFrom, Val)); return false; } @@ -815,7 +893,7 @@ LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB) { DEBUG(dbgs() << "LVI Getting block end value " << *V << " at '" << BB->getName() << "'\n"); - block_value_stack.push(std::make_pair(BB, V)); + BlockValueStack.push(std::make_pair(BB, V)); solve(); LVILatticeVal Result = getBlockValue(V, BB); @@ -856,8 +934,8 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, worklist.push_back(OldSucc); DenseSet ClearSet; - for (std::set, Value*> >::iterator - I = OverDefinedCache.begin(), E = OverDefinedCache.end(); I != E; ++I) { + for (DenseSet::iterator I = OverDefinedCache.begin(), + E = OverDefinedCache.end(); I != E; ++I) { if (I->first == OldSucc) ClearSet.insert(I->second); } @@ -877,7 +955,7 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, for (DenseSet::iterator I = ClearSet.begin(), E = ClearSet.end(); I != E; ++I) { // If a value was marked overdefined in OldSucc, and is here too... - std::set, Value*> >::iterator OI = + DenseSet::iterator OI = OverDefinedCache.find(std::make_pair(ToUpdate, *I)); if (OI == OverDefinedCache.end()) continue; @@ -914,12 +992,19 @@ static LazyValueInfoCache &getCache(void *&PImpl) { bool LazyValueInfo::runOnFunction(Function &F) { if (PImpl) getCache(PImpl).clear(); - + TD = getAnalysisIfAvailable(); + TLI = &getAnalysis(); + // Fully lazy. return false; } +void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesAll(); + AU.addRequired(); +} + void LazyValueInfo::releaseMemory() { // If the cache was allocated, free it. if (PImpl) { @@ -968,7 +1053,8 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, // If we know the value is a constant, evaluate the conditional. Constant *Res = 0; if (Result.isConstant()) { - Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, TD); + Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, TD, + TLI); if (ConstantInt *ResCI = dyn_cast(Res)) return ResCI->isZero() ? False : True; return Unknown; @@ -1009,13 +1095,15 @@ 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, TD, + TLI); if (Res->isNullValue()) return 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, TD, + TLI); if (Res->isNullValue()) return True; }