diff options
Diffstat (limited to 'contrib/llvm/lib/Analysis/LazyValueInfo.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/LazyValueInfo.cpp | 553 |
1 files changed, 342 insertions, 211 deletions
diff --git a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp index 9f919f7..4de56f1 100644 --- a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp +++ b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp @@ -1,4 +1,4 @@ -//===- LazyValueInfo.cpp - Value constraint analysis ----------------------===// +//===- LazyValueInfo.cpp - Value constraint analysis ------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // @@ -15,12 +15,14 @@ #include "llvm/Analysis/LazyValueInfo.h" #include "llvm/ADT/DenseSet.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/Analysis/AssumptionCache.h" #include "llvm/Analysis/ConstantFolding.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" @@ -38,6 +40,7 @@ using namespace PatternMatch; char LazyValueInfo::ID = 0; INITIALIZE_PASS_BEGIN(LazyValueInfo, "lazy-value-info", "Lazy Value Information Analysis", false, true) +INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker) INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo) INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info", "Lazy Value Information Analysis", false, true) @@ -51,8 +54,7 @@ namespace llvm { // LVILatticeVal //===----------------------------------------------------------------------===// -/// LVILatticeVal - This is the information tracked by LazyValueInfo for each -/// value. +/// This is the information tracked by LazyValueInfo for each value. /// /// FIXME: This is basically just for bringup, this can be made a lot more rich /// in the future. @@ -60,19 +62,19 @@ namespace llvm { namespace { class LVILatticeVal { enum LatticeValueTy { - /// undefined - This Value has no known value yet. + /// This Value has no known value yet. undefined, - /// constant - This Value has a specific constant value. + /// This Value has a specific constant value. constant, - /// notconstant - This Value is known to not have the specified value. + + /// This Value is known to not have the specified value. notconstant, - /// constantrange - The Value falls within this range. + /// The Value falls within this range. constantrange, - /// overdefined - This value is not known to be constant, and we know that - /// it has a value. + /// This value is not known to be constant, and we know that it has a value. overdefined }; @@ -125,7 +127,7 @@ public: return Range; } - /// markOverdefined - Return true if this is a change in status. + /// Return true if this is a change in status. bool markOverdefined() { if (isOverdefined()) return false; @@ -133,7 +135,7 @@ public: return true; } - /// markConstant - Return true if this is a change in status. + /// Return true if this is a change in status. bool markConstant(Constant *V) { assert(V && "Marking constant with NULL"); if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) @@ -149,7 +151,7 @@ public: return true; } - /// markNotConstant - Return true if this is a change in status. + /// Return true if this is a change in status. bool markNotConstant(Constant *V) { assert(V && "Marking constant with NULL"); if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) @@ -167,7 +169,7 @@ public: return true; } - /// markConstantRange - Return true if this is a change in status. + /// Return true if this is a change in status. bool markConstantRange(const ConstantRange NewR) { if (isConstantRange()) { if (NewR.isEmptySet()) @@ -187,7 +189,7 @@ public: return true; } - /// mergeIn - Merge the specified lattice value into this one, updating this + /// Merge the specified lattice value into this one, updating this /// one and returning true if anything changed. bool mergeIn(const LVILatticeVal &RHS) { if (RHS.isUndefined() || isOverdefined()) return false; @@ -295,8 +297,7 @@ raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) { //===----------------------------------------------------------------------===// namespace { - /// LVIValueHandle - A callback value handle updates the cache when - /// values are erased. + /// A callback value handle updates the cache when values are erased. class LazyValueInfoCache; struct LVIValueHandle : public CallbackVH { LazyValueInfoCache *Parent; @@ -312,59 +313,67 @@ namespace { } namespace { - /// LazyValueInfoCache - This is the cache kept by LazyValueInfo which + /// This is the cache kept by LazyValueInfo which /// maintains information about queries across the clients' queries. class LazyValueInfoCache { - /// ValueCacheEntryTy - This is all of the cached block information for - /// exactly one Value*. The entries are sorted by the BasicBlock* of the + /// 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<AssertingVH<BasicBlock>, LVILatticeVal> ValueCacheEntryTy; - /// ValueCache - This is all of the cached information for all values, + /// This is all of the cached information for all values, /// mapped from Value* to key information. std::map<LVIValueHandle, ValueCacheEntryTy> 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 + /// 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<AssertingVH<BasicBlock>, Value*> OverDefinedPairTy; DenseSet<OverDefinedPairTy> OverDefinedCache; - /// SeenBlocks - Keep track of all blocks that we have ever seen, so we + /// Keep track of all blocks that we have ever seen, so we /// don't spend time removing unused blocks from our caches. DenseSet<AssertingVH<BasicBlock> > SeenBlocks; - /// BlockValueStack - This stack holds the state of the value solver - /// during a query. It basically emulates the callstack of the naive + /// 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<std::pair<BasicBlock*, Value*> > BlockValueStack; + + /// Keeps track of which block-value pairs are in BlockValueStack. + DenseSet<std::pair<BasicBlock*, Value*> > BlockValueSet; + + /// Push BV onto BlockValueStack unless it's already in there. + /// Returns true on success. + bool pushBlockValue(const std::pair<BasicBlock *, Value *> &BV) { + if (BlockValueSet.count(BV)) + return false; // It's already in the stack. + + BlockValueStack.push(BV); + BlockValueSet.insert(BV); + return true; + } + + /// A pointer to the cache of @llvm.assume calls. + AssumptionCache *AC; + /// An optional DL pointer. + const DataLayout *DL; + /// An optional DT pointer. + DominatorTree *DT; friend struct LVIValueHandle; - - /// OverDefinedCacheUpdater - A helper object that ensures that the - /// OverDefinedCache is updated whenever solveBlockValue returns. - struct OverDefinedCacheUpdater { - LazyValueInfoCache *Parent; - Value *Val; - BasicBlock *BB; - LVILatticeVal &BBLV; - - OverDefinedCacheUpdater(Value *V, BasicBlock *B, LVILatticeVal &LV, - LazyValueInfoCache *P) - : Parent(P), Val(V), BB(B), BBLV(LV) { } - - bool markResult(bool changed) { - if (changed && BBLV.isOverdefined()) - Parent->OverDefinedCache.insert(std::make_pair(BB, Val)); - return changed; - } - }; - + void insertResult(Value *Val, BasicBlock *BB, const LVILatticeVal &Result) { + SeenBlocks.insert(BB); + lookup(Val)[BB] = Result; + if (Result.isOverdefined()) + OverDefinedCache.insert(std::make_pair(BB, Val)); + } 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 @@ -377,6 +386,8 @@ namespace { PHINode *PN, BasicBlock *BB); bool solveBlockValueConstantRange(LVILatticeVal &BBLV, Instruction *BBI, BasicBlock *BB); + void mergeAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV, + Instruction *BBI); void solve(); @@ -385,20 +396,26 @@ namespace { } public: - /// getValueInBlock - This is the query interface to determine the lattice + /// 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); + + /// 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 + /// 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 - /// NewSucc. + /// This is the update interface to inform the cache that an edge from + /// PredBB to OldSucc has been threaded to be from PredBB to NewSucc. void threadEdge(BasicBlock *PredBB,BasicBlock *OldSucc,BasicBlock *NewSucc); - /// eraseBlock - This is part of the update interface to inform the cache + /// This is part of the update interface to inform the cache /// that a block has been deleted. void eraseBlock(BasicBlock *BB); @@ -408,6 +425,10 @@ namespace { ValueCache.clear(); OverDefinedCache.clear(); } + + LazyValueInfoCache(AssumptionCache *AC, const DataLayout *DL = nullptr, + DominatorTree *DT = nullptr) + : AC(AC), DL(DL), DT(DT) {} }; } // end anonymous namespace @@ -415,17 +436,11 @@ void LVIValueHandle::deleted() { typedef std::pair<AssertingVH<BasicBlock>, Value*> OverDefinedPairTy; SmallVector<OverDefinedPairTy, 4> ToErase; - for (DenseSet<OverDefinedPairTy>::iterator - I = Parent->OverDefinedCache.begin(), - E = Parent->OverDefinedCache.end(); - I != E; ++I) { - if (I->second == getValPtr()) - ToErase.push_back(*I); - } - - for (SmallVectorImpl<OverDefinedPairTy>::iterator I = ToErase.begin(), - E = ToErase.end(); I != E; ++I) - Parent->OverDefinedCache.erase(*I); + for (const OverDefinedPairTy &P : Parent->OverDefinedCache) + if (P.second == getValPtr()) + ToErase.push_back(P); + for (const OverDefinedPairTy &P : ToErase) + Parent->OverDefinedCache.erase(P); // This erasure deallocates *this, so it MUST happen after we're done // using any and all members of *this. @@ -440,15 +455,11 @@ void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { SeenBlocks.erase(I); SmallVector<OverDefinedPairTy, 4> ToErase; - for (DenseSet<OverDefinedPairTy>::iterator I = OverDefinedCache.begin(), - E = OverDefinedCache.end(); I != E; ++I) { - if (I->first == BB) - ToErase.push_back(*I); - } - - for (SmallVectorImpl<OverDefinedPairTy>::iterator I = ToErase.begin(), - E = ToErase.end(); I != E; ++I) - OverDefinedCache.erase(*I); + for (const OverDefinedPairTy& P : OverDefinedCache) + if (P.first == BB) + ToErase.push_back(P); + for (const OverDefinedPairTy &P : ToErase) + OverDefinedCache.erase(P); for (std::map<LVIValueHandle, ValueCacheEntryTy>::iterator I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I) @@ -458,9 +469,18 @@ void LazyValueInfoCache::eraseBlock(BasicBlock *BB) { void LazyValueInfoCache::solve() { while (!BlockValueStack.empty()) { std::pair<BasicBlock*, Value*> &e = BlockValueStack.top(); + assert(BlockValueSet.count(e) && "Stack value should be in BlockValueSet!"); + if (solveBlockValue(e.second, e.first)) { - assert(BlockValueStack.top() == e); + // The work item was completely processed. + assert(BlockValueStack.top() == e && "Nothing should have been pushed!"); + assert(lookup(e.second).count(e.first) && "Result should be in cache!"); + BlockValueStack.pop(); + BlockValueSet.erase(e); + } else { + // More work needs to be done before revisiting. + assert(BlockValueStack.top() != e && "Stack should have been pushed!"); } } } @@ -490,44 +510,40 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { if (isa<Constant>(Val)) return true; - ValueCacheEntryTy &Cache = lookup(Val); - SeenBlocks.insert(BB); - LVILatticeVal &BBLV = Cache[BB]; - - // OverDefinedCacheUpdater is a helper object that will update - // the OverDefinedCache for us when this method exits. Make sure to - // call markResult on it as we exist, passing a bool to indicate if the - // 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'); - - // Since we're reusing a cached value here, we don't need to update the - // OverDefinedCahce. The cache will have been properly updated - // whenever the cached value was inserted. - ODCacheUpdater.markResult(false); + if (lookup(Val).count(BB)) { + // If we have a cached value, use that. + DEBUG(dbgs() << " reuse BB '" << BB->getName() + << "' val=" << lookup(Val)[BB] << '\n'); + + // Since we're reusing a cached value, we don't need to update the + // OverDefinedCache. The cache will have been properly updated whenever the + // cached value was inserted. return true; } - // Otherwise, this is the first time we're seeing this block. Reset the - // lattice value to overdefined, so that cycles will terminate and be - // conservatively correct. - BBLV.markOverdefined(); + // Hold off inserting this value into the Cache in case we have to return + // false and come back later. + LVILatticeVal Res; Instruction *BBI = dyn_cast<Instruction>(Val); if (!BBI || BBI->getParent() != BB) { - return ODCacheUpdater.markResult(solveBlockValueNonLocal(BBLV, Val, BB)); + if (!solveBlockValueNonLocal(Res, Val, BB)) + return false; + insertResult(Val, BB, Res); + return true; } if (PHINode *PN = dyn_cast<PHINode>(BBI)) { - return ODCacheUpdater.markResult(solveBlockValuePHINode(BBLV, PN, BB)); + if (!solveBlockValuePHINode(Res, PN, BB)) + return false; + insertResult(Val, BB, Res); + return true; } if (AllocaInst *AI = dyn_cast<AllocaInst>(BBI)) { - BBLV = LVILatticeVal::getNot(ConstantPointerNull::get(AI->getType())); - return ODCacheUpdater.markResult(true); + Res = LVILatticeVal::getNot(ConstantPointerNull::get(AI->getType())); + insertResult(Val, BB, Res); + return true; } // We can only analyze the definitions of certain classes of instructions @@ -537,8 +553,9 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { !BBI->getType()->isIntegerTy()) { DEBUG(dbgs() << " compute BB '" << BB->getName() << "' - overdefined because inst def found.\n"); - BBLV.markOverdefined(); - return ODCacheUpdater.markResult(true); + Res.markOverdefined(); + insertResult(Val, BB, Res); + return true; } // FIXME: We're currently limited to binops with a constant RHS. This should @@ -548,11 +565,15 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) { DEBUG(dbgs() << " compute BB '" << BB->getName() << "' - overdefined because inst def found.\n"); - BBLV.markOverdefined(); - return ODCacheUpdater.markResult(true); + Res.markOverdefined(); + insertResult(Val, BB, Res); + return true; } - return ODCacheUpdater.markResult(solveBlockValueConstantRange(BBLV, BBI, BB)); + if (!solveBlockValueConstantRange(Res, BBI, BB)) + return false; + insertResult(Val, BB, Res); + return true; } static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) { @@ -597,9 +618,8 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, // 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)) { + for (Instruction &I : *BB) { + if (InstructionDereferencesPointer(&I, UnderlyingVal)) { NotNull = true; break; } @@ -669,7 +689,10 @@ 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; @@ -694,16 +717,53 @@ 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 in 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<Instruction>(Val); + if (!BBI) + return; + + for (auto &AssumeVH : AC->assumptions()) { + if (!AssumeVH) + continue; + auto *I = cast<CallInst>(AssumeVH); + if (!isValidAssumeForContext(I, BBI, DL, DT)) + continue; + + Value *C = I->getArgOperand(0); + if (ICmpInst *ICI = dyn_cast<ICmpInst>(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) { // Figure out the range of the LHS. If that fails, bail. if (!hasBlockValue(BBI->getOperand(0), BB)) { - BlockValueStack.push(std::make_pair(BB, BBI->getOperand(0))); - return false; + if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0)))) + return false; + BBLV.markOverdefined(); + return true; } LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB); + mergeAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI); if (!LHSVal.isConstantRange()) { BBLV.markOverdefined(); return true; @@ -775,6 +835,47 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, return true; } +bool getValueFromFromCondition(Value *Val, ICmpInst *ICI, + LVILatticeVal &Result, bool isTrueDest) { + if (ICI && isa<Constant>(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<Constant>(ICI->getOperand(1))); + else + Result = LVILatticeVal::getNot(cast<Constant>(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<ConstantInt>(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, @@ -783,7 +884,7 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom, // know that v != 0. if (BranchInst *BI = dyn_cast<BranchInst>(BBFrom->getTerminator())) { // If this is a conditional branch and only one successor goes to BBTo, then - // we maybe able to infer something from the condition. + // we may be able to infer something from the condition. if (BI->isConditional() && BI->getSuccessor(0) != BI->getSuccessor(1)) { bool isTrueDest = BI->getSuccessor(0) == BBTo; @@ -800,42 +901,9 @@ static bool getEdgeValueLocal(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<ICmpInst>(BI->getCondition()); - if (ICI && isa<Constant>(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<Constant>(ICI->getOperand(1))); - else - Result = LVILatticeVal::getNot(cast<Constant>(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<ConstantInt>(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); + if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition())) + if (getValueFromFromCondition(Val, ICI, Result, isTrueDest)) return true; - } - } } } @@ -849,8 +917,7 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom, unsigned BitWidth = Val->getType()->getIntegerBitWidth(); ConstantRange EdgesVals(BitWidth, DefaultCase/*isFullSet*/); - for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end(); - i != e; ++i) { + for (SwitchInst::CaseIt i : SI->cases()) { ConstantRange EdgeVal(i.getCaseValue()->getValue()); if (DefaultCase) { // It is possible that the default destination is the destination of @@ -866,10 +933,11 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom, return false; } -/// \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. +/// \brief Compute the value of Val on the edge BBFrom -> BBTo or the value at +/// the basic block if the edge does not constrain Val. bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, - BasicBlock *BBTo, LVILatticeVal &Result) { + BasicBlock *BBTo, LVILatticeVal &Result, + Instruction *CxtI) { // If already a constant, there is nothing to compute. if (Constant *VC = dyn_cast<Constant>(Val)) { Result = LVILatticeVal::get(VC); @@ -878,19 +946,25 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, if (getEdgeValueLocal(Val, BBFrom, BBTo, Result)) { if (!Result.isConstantRange() || - Result.getConstantRange().getSingleElement()) + 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; + if (pushBlockValue(std::make_pair(BBFrom, Val))) + return false; + Result.markOverdefined(); + return true; } // 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; @@ -901,36 +975,64 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, } if (!hasBlockValue(Val, BBFrom)) { - BlockValueStack.push(std::make_pair(BBFrom, Val)); - return false; + if (pushBlockValue(std::make_pair(BBFrom, Val))) + return false; + Result.markOverdefined(); + return true; } - // if we couldn't compute the value on the edge, use the value from the BB + // 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) { +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)); + assert(BlockValueStack.empty() && BlockValueSet.empty()); + pushBlockValue(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?"); } @@ -947,7 +1049,7 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, // we clear their entries from the cache, and allow lazy updating to recompute // them when needed. - // The updating process is fairly simple: we need to dropped cached info + // The updating process is fairly simple: we need to drop cached info // for all values that were marked overdefined in OldSucc, and for those same // values in any successor of OldSucc (except NewSucc) in which they were // also marked overdefined. @@ -955,11 +1057,9 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, worklist.push_back(OldSucc); DenseSet<Value*> ClearSet; - for (DenseSet<OverDefinedPairTy>::iterator I = OverDefinedCache.begin(), - E = OverDefinedCache.end(); I != E; ++I) { - if (I->first == OldSucc) - ClearSet.insert(I->second); - } + for (OverDefinedPairTy &P : OverDefinedCache) + if (P.first == OldSucc) + ClearSet.insert(P.second); // Use a worklist to perform a depth-first search of OldSucc's successors. // NOTE: We do not need a visited list since any blocks we have already @@ -973,15 +1073,14 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, if (ToUpdate == NewSucc) continue; bool changed = false; - for (DenseSet<Value*>::iterator I = ClearSet.begin(), E = ClearSet.end(); - I != E; ++I) { + for (Value *V : ClearSet) { // If a value was marked overdefined in OldSucc, and is here too... DenseSet<OverDefinedPairTy>::iterator OI = - OverDefinedCache.find(std::make_pair(ToUpdate, *I)); + OverDefinedCache.find(std::make_pair(ToUpdate, V)); if (OI == OverDefinedCache.end()) continue; // Remove it from the caches. - ValueCacheEntryTy &Entry = ValueCache[LVIValueHandle(*I, this)]; + ValueCacheEntryTy &Entry = ValueCache[LVIValueHandle(V, this)]; ValueCacheEntryTy::iterator CI = Entry.find(ToUpdate); assert(CI != Entry.end() && "Couldn't find entry to update?"); @@ -1003,41 +1102,53 @@ void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc, // LazyValueInfo Impl //===----------------------------------------------------------------------===// -/// getCache - This lazily constructs the LazyValueInfoCache. -static LazyValueInfoCache &getCache(void *&PImpl) { +/// This lazily constructs the LazyValueInfoCache. +static LazyValueInfoCache &getCache(void *&PImpl, AssumptionCache *AC, + const DataLayout *DL = nullptr, + DominatorTree *DT = nullptr) { if (!PImpl) - PImpl = new LazyValueInfoCache(); + PImpl = new LazyValueInfoCache(AC, DL, DT); return *static_cast<LazyValueInfoCache*>(PImpl); } bool LazyValueInfo::runOnFunction(Function &F) { - if (PImpl) - getCache(PImpl).clear(); + AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F); + + DominatorTreeWrapperPass *DTWP = + getAnalysisIfAvailable<DominatorTreeWrapperPass>(); + DT = DTWP ? &DTWP->getDomTree() : nullptr; DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>(); DL = DLP ? &DLP->getDataLayout() : nullptr; + TLI = &getAnalysis<TargetLibraryInfo>(); + if (PImpl) + getCache(PImpl, AC, DL, DT).clear(); + // Fully lazy. return false; } void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const { AU.setPreservesAll(); + AU.addRequired<AssumptionCacheTracker>(); AU.addRequired<TargetLibraryInfo>(); } void LazyValueInfo::releaseMemory() { // If the cache was allocated, free it. if (PImpl) { - delete &getCache(PImpl); + delete &getCache(PImpl, AC); 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, AC, DL, DT).getValueInBlock(V, BB, CxtI); + if (Result.isConstant()) return Result.getConstant(); if (Result.isConstantRange()) { @@ -1048,12 +1159,14 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) { return nullptr; } -/// getConstantOnEdge - Determine whether the specified value is known to be a +/// 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, AC, DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI); + if (Result.isConstant()) return Result.getConstant(); if (Result.isConstantRange()) { @@ -1064,51 +1177,47 @@ Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB, 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 = nullptr; if (Result.isConstant()) { Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, DL, TLI); if (ConstantInt *ResCI = dyn_cast<ConstantInt>(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<ConstantInt>(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()) { @@ -1120,26 +1229,48 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, 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, DL, TLI); if (Res->isNullValue()) - return True; + return LazyValueInfo::True; } - return Unknown; + return LazyValueInfo::Unknown; } - return Unknown; + return LazyValueInfo::Unknown; +} + +/// 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, AC, 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, AC, 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, AC, DL, DT).threadEdge(PredBB, OldSucc, NewSucc); } void LazyValueInfo::eraseBlock(BasicBlock *BB) { - if (PImpl) getCache(PImpl).eraseBlock(BB); + if (PImpl) + getCache(PImpl, AC, DL, DT).eraseBlock(BB); } |
