X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FLazyValueInfo.cpp;h=c712c9f487d1260c01f5f1a62369e5745cd0fce5;hb=e2eb8b632dcbd576c340af34407ef0f9f5a5458b;hp=a65480c2e407e8ea96652d1583645ebfec2cd902;hpb=a4697dad1926a8c91c12cd6663f5ddc7c4cd16c7;p=oota-llvm.git diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp index a65480c2e40..c712c9f487d 100644 --- a/lib/Analysis/LazyValueInfo.cpp +++ b/lib/Analysis/LazyValueInfo.cpp @@ -15,12 +15,14 @@ #include "llvm/Analysis/LazyValueInfo.h" #include "llvm/ADT/DenseSet.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/Analysis/AssumptionTracker.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(AssumptionTracker) INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo) INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info", "Lazy Value Information Analysis", false, true) @@ -338,6 +341,13 @@ namespace { /// 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; @@ -364,7 +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 @@ -377,6 +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(); @@ -387,11 +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 @@ -408,6 +428,10 @@ namespace { ValueCache.clear(); OverDefinedCache.clear(); } + + LazyValueInfoCache(AssumptionTracker *AT, + const DataLayout *DL = nullptr, + DominatorTree *DT = nullptr) : AT(AT), DL(DL), DT(DT) {} }; } // end anonymous namespace @@ -500,7 +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'); @@ -625,9 +648,9 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV, // Loop over all of our predecessors, merging what we know from them into // result. bool EdgesMissing = false; - for (BasicBlock *Pred : predecessors(BB)) { + for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { LVILatticeVal EdgeResult; - EdgesMissing |= !getEdgeValue(Val, Pred, BB, EdgeResult); + EdgesMissing |= !getEdgeValue(Val, *PI, BB, EdgeResult); if (EdgesMissing) continue; @@ -669,7 +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; @@ -694,6 +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) { @@ -704,6 +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; @@ -775,6 +832,47 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV, 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, @@ -801,41 +899,8 @@ 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(BI->getCondition()); - 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; - } - } + if (getValueFromFromCondition(Val, ICI, Result, isTrueDest)) + return true; } } @@ -869,7 +934,8 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom, /// \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) { + 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); @@ -891,6 +957,10 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, // 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; @@ -907,30 +977,54 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom, // 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)); 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?"); } @@ -1004,39 +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) { - if (PImpl) - getCache(PImpl).clear(); + AT = &getAnalysis(); + + DominatorTreeWrapperPass *DTWP = + getAnalysisIfAvailable(); + DT = DTWP ? &DTWP->getDomTree() : nullptr; DataLayoutPass *DLP = getAnalysisIfAvailable(); DL = DLP ? &DLP->getDataLayout() : nullptr; TLI = &getAnalysis(); + if (PImpl) + 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); + 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(); @@ -1051,8 +1157,10 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB) { /// 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(); @@ -1064,51 +1172,47 @@ 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(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()) { @@ -1120,26 +1224,48 @@ 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; +} + +/// 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); }