-//===- LazyValueInfo.cpp - Value constraint analysis ----------------------===//
+//===- LazyValueInfo.cpp - Value constraint analysis ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
-#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/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 <map>
-#include <set>
#include <stack>
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 {
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
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;
if (NewR.isEmptySet())
return markOverdefined();
- bool changed = Range == NewR;
+ bool changed = Range != NewR;
Range = NewR;
return changed;
}
// 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<ConstantInt>(
ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
getConstant(),
// 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<ConstantInt>(
ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
getNotConstant(),
} // 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";
//===----------------------------------------------------------------------===//
namespace {
+ /// LVIValueHandle - A callback value handle updates 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() override;
+ void allUsesReplacedWith(Value *V) override {
+ 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<AssertingVH<BasicBlock>, 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<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
+ /// 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
+ /// 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
+ /// recursive value lookup process.
+ std::stack<std::pair<BasicBlock*, Value*> > 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;
/// OverDefinedCacheUpdater - A helper object that ensures that the
/// OverDefinedCache is updated whenever solveBlockValue returns.
return changed;
}
};
-
- /// ValueCache - 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
- /// for cache updating.
- std::set<std::pair<AssertingVH<BasicBlock>, Value*> > OverDefinedCache;
+
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
PHINode *PN, BasicBlock *BB);
bool solveBlockValueConstantRange(LVILatticeVal &BBLV,
Instruction *BBI, BasicBlock *BB);
+ void mergeAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
+ Instruction *BBI);
void solve();
ValueCacheEntryTy &lookup(Value *V) {
return ValueCache[LVIValueHandle(V, this)];
}
-
- std::stack<std::pair<BasicBlock*, Value*> > block_value_stack;
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
/// 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
-void LazyValueInfoCache::LVIValueHandle::deleted() {
- for (std::set<std::pair<AssertingVH<BasicBlock>, Value*> >::iterator
+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; ) {
- std::set<std::pair<AssertingVH<BasicBlock>, 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 (SmallVectorImpl<OverDefinedPairTy>::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.
}
void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
- for (std::set<std::pair<AssertingVH<BasicBlock>, Value*> >::iterator
- I = OverDefinedCache.begin(), E = OverDefinedCache.end(); I != E; ) {
- std::set<std::pair<AssertingVH<BasicBlock>, Value*> >::iterator tmp = I;
- ++I;
- if (tmp->first == BB)
- OverDefinedCache.erase(tmp);
+ // Shortcut if we have never seen this block.
+ DenseSet<AssertingVH<BasicBlock> >::iterator I = SeenBlocks.find(BB);
+ if (I == SeenBlocks.end())
+ return;
+ 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 (std::map<LVIValueHandle, ValueCacheEntryTy>::iterator
I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I)
I->second.erase(BB);
}
void LazyValueInfoCache::solve() {
- while (!block_value_stack.empty()) {
- std::pair<BasicBlock*, Value*> &e = block_value_stack.top();
- if (solveBlockValue(e.second, e.first))
- block_value_stack.pop();
+ while (!BlockValueStack.empty()) {
+ std::pair<BasicBlock*, Value*> &e = BlockValueStack.top();
+ if (solveBlockValue(e.second, e.first)) {
+ assert(BlockValueStack.top() == e);
+ BlockValueStack.pop();
+ }
}
}
if (isa<Constant>(Val))
return true;
- return lookup(Val).count(BB);
+ LVIValueHandle ValHandle(Val, this);
+ std::map<LVIValueHandle, ValueCacheEntryTy>::iterator I =
+ ValueCache.find(ValHandle);
+ if (I == ValueCache.end()) return false;
+ return I->second.count(BB);
}
LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) {
if (Constant *VC = dyn_cast<Constant>(Val))
return LVILatticeVal::get(VC);
+ SeenBlocks.insert(BB);
return lookup(Val)[BB];
}
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.
+ // call markResult on it as we exit, passing a bool to indicate if the
+ // cache needs updating, i.e. if we have solved 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
+ // OverDefinedCache. The cache will have been properly updated
// whenever the cached value was inserted.
ODCacheUpdater.markResult(false);
return true;
BBLV.markOverdefined();
Instruction *BBI = dyn_cast<Instruction>(Val);
- if (BBI == 0 || BBI->getParent() != BB) {
+ if (!BBI || BBI->getParent() != BB) {
return ODCacheUpdater.markResult(solveBlockValueNonLocal(BBLV, Val, BB));
}
return ODCacheUpdater.markResult(solveBlockValuePHINode(BBLV, PN, BB));
}
+ if (AllocaInst *AI = dyn_cast<AllocaInst>(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;
static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) {
if (LoadInst *L = dyn_cast<LoadInst>(I)) {
return L->getPointerAddressSpace() == 0 &&
- GetUnderlyingObject(L->getPointerOperand()) ==
- GetUnderlyingObject(Ptr);
+ GetUnderlyingObject(L->getPointerOperand()) == Ptr;
}
if (StoreInst *S = dyn_cast<StoreInst>(I)) {
return S->getPointerAddressSpace() == 0 &&
- GetUnderlyingObject(S->getPointerOperand()) ==
- GetUnderlyingObject(Ptr);
+ GetUnderlyingObject(S->getPointerOperand()) == Ptr;
+ }
+ if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) {
+ if (MI->isVolatile()) return false;
+
+ // FIXME: check whether it has a valuerange that excludes zero?
+ ConstantInt *Len = dyn_cast<ConstantInt>(MI->getLength());
+ if (!Len || Len->isZero()) return false;
+
+ if (MI->getDestAddressSpace() == 0)
+ if (GetUnderlyingObject(MI->getRawDest()) == Ptr)
+ return true;
+ if (MemTransferInst *MTI = dyn_cast<MemTransferInst>(MI))
+ if (MTI->getSourceAddressSpace() == 0)
+ if (GetUnderlyingObject(MTI->getRawSource()) == Ptr)
+ return true;
}
- // FIXME: llvm.memset, etc.
return false;
}
// 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 (isKnownNonNull(Val)) {
+ NotNull = true;
+ } else {
+ 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;
+ }
+ }
}
}
}
if (BB == &BB->getParent()->getEntryBlock()) {
assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
if (NotNull) {
-
const PointerType *PTy = cast<PointerType>(Val->getType());
+ PointerType *PTy = cast<PointerType>(Val->getType());
Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
} else {
Result.markOverdefined();
// 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<PointerType>(Val->getType());
+ PointerType *PTy = cast<PointerType>(Val->getType());
Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
}
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;
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 &I : AT->assumptions(BBI->getParent()->getParent())) {
+ 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)) {
- block_value_stack.push(std::make_pair(BB, BBI->getOperand(0)));
+ BlockValueStack.push(std::make_pair(BB, BBI->getOperand(0)));
return false;
}
LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
+ mergeAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
if (!LHSVal.isConstantRange()) {
BBLV.markOverdefined();
return true;
ConstantRange LHSRange = LHSVal.getConstantRange();
ConstantRange RHSRange(1);
- const IntegerType *ResultTy = cast<IntegerType>(BBI->getType());
+ IntegerType *ResultTy = cast<IntegerType>(BBI->getType());
if (isa<BinaryOperator>(BBI)) {
if (ConstantInt *RHS = dyn_cast<ConstantInt>(BBI->getOperand(1))) {
RHSRange = ConstantRange(RHS->getValue());
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<Constant>(Val)) {
- Result = LVILatticeVal::get(VC);
- 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,
+ 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<BranchInst>(BBFrom->getTerminator())) {
// 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 && ICI->getOperand(0) == Val &&
- isa<Constant>(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<Constant>(ICI->getOperand(1)));
- else
- Result = LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
- return true;
- }
-
- if (ConstantInt *CI = dyn_cast<ConstantInt>(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.
- 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<SwitchInst>(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;
}
- block_value_stack.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<Constant>(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");
- block_value_stack.push(std::make_pair(BB, V));
+ 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?");
}
// 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.
worklist.push_back(OldSucc);
DenseSet<Value*> ClearSet;
- for (std::set<std::pair<AssertingVH<BasicBlock>, Value*> >::iterator
- I = OverDefinedCache.begin(), E = OverDefinedCache.end(); I != E; ++I) {
+ for (DenseSet<OverDefinedPairTy>::iterator I = OverDefinedCache.begin(),
+ E = OverDefinedCache.end(); I != E; ++I) {
if (I->first == OldSucc)
ClearSet.insert(I->second);
}
for (DenseSet<Value*>::iterator I = ClearSet.begin(), E = ClearSet.end();
I != E; ++I) {
// If a value was marked overdefined in OldSucc, and is here too...
- std::set<std::pair<AssertingVH<BasicBlock>, Value*> >::iterator OI =
+ DenseSet<OverDefinedPairTy>::iterator OI =
OverDefinedCache.find(std::make_pair(ToUpdate, *I));
if (OI == OverDefinedCache.end()) continue;
//===----------------------------------------------------------------------===//
/// 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<LazyValueInfoCache*>(PImpl);
}
bool LazyValueInfo::runOnFunction(Function &F) {
+ AT = &getAnalysis<AssumptionTracker>();
+
+ 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).clear();
-
- TD = getAnalysisIfAvailable<TargetData>();
+ getCache(PImpl, AT, DL, DT).clear();
+
// Fully lazy.
return false;
}
+void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<AssumptionTracker>();
+ AU.addRequired<TargetLibraryInfo>();
+}
+
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();
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();
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<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()) {
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);
}
projects / oota-llvm.git / blobdiff