-//===- 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/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/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/ADT/DenseMap.h"
-#include "llvm/ADT/PointerIntPair.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include <map>
+#include <stack>
using namespace llvm;
+using namespace PatternMatch;
+
+#define DEBUG_TYPE "lazy-value-info"
char LazyValueInfo::ID = 0;
-INITIALIZE_PASS(LazyValueInfo, "lazy-value-info",
- "Lazy Value Information Analysis", false, true);
+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 {
FunctionPass *createLazyValueInfoPass() { return new LazyValueInfo(); }
namespace {
class LVILatticeVal {
enum LatticeValueTy {
- /// undefined - This LLVM Value has no known value yet.
+ /// undefined - This Value has no known value yet.
undefined,
- /// constant - This LLVM Value has a specific constant value.
- constant,
- /// notconstant - This LLVM value is known to not have the specified value.
+ /// constant - This Value has a specific constant value.
+ constant,
+ /// notconstant - This Value is known to not have the specified value.
notconstant,
-
- /// overdefined - This instruction is not known to be constant, and we know
+
+ /// 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
};
/// Val: This stores the current lattice value along with the Constant* for
/// the constant if this is a 'constant' or 'notconstant' value.
- PointerIntPair<Constant *, 2, LatticeValueTy> Val;
+ LatticeValueTy Tag;
+ Constant *Val;
+ ConstantRange Range;
public:
- LVILatticeVal() : Val(0, undefined) {}
+ LVILatticeVal() : Tag(undefined), Val(nullptr), Range(1, true) {}
static LVILatticeVal get(Constant *C) {
LVILatticeVal Res;
- Res.markConstant(C);
+ if (!isa<UndefValue>(C))
+ Res.markConstant(C);
return Res;
}
static LVILatticeVal getNot(Constant *C) {
LVILatticeVal Res;
- Res.markNotConstant(C);
+ if (!isa<UndefValue>(C))
+ Res.markNotConstant(C);
+ return Res;
+ }
+ static LVILatticeVal getRange(ConstantRange CR) {
+ LVILatticeVal Res;
+ Res.markConstantRange(CR);
return Res;
}
- bool isUndefined() const { return Val.getInt() == undefined; }
- bool isConstant() const { return Val.getInt() == constant; }
- bool isNotConstant() const { return Val.getInt() == notconstant; }
- bool isOverdefined() const { return Val.getInt() == overdefined; }
+ bool isUndefined() const { return Tag == undefined; }
+ bool isConstant() const { return Tag == constant; }
+ bool isNotConstant() const { return Tag == notconstant; }
+ bool isConstantRange() const { return Tag == constantrange; }
+ bool isOverdefined() const { return Tag == overdefined; }
Constant *getConstant() const {
assert(isConstant() && "Cannot get the constant of a non-constant!");
- return Val.getPointer();
+ return Val;
}
Constant *getNotConstant() const {
assert(isNotConstant() && "Cannot get the constant of a non-notconstant!");
- return Val.getPointer();
+ return Val;
+ }
+
+ ConstantRange getConstantRange() const {
+ assert(isConstantRange() &&
+ "Cannot get the constant-range of a non-constant-range!");
+ return Range;
}
/// markOverdefined - Return true if this is a change in status.
bool markOverdefined() {
if (isOverdefined())
return false;
- Val.setInt(overdefined);
+ Tag = overdefined;
return true;
}
/// markConstant - Return true if this is a change in status.
bool markConstant(Constant *V) {
- if (isConstant()) {
- assert(getConstant() == V && "Marking constant with different value");
+ assert(V && "Marking constant with NULL");
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
+ return markConstantRange(ConstantRange(CI->getValue()));
+ if (isa<UndefValue>(V))
return false;
- }
-
+
+ assert((!isConstant() || getConstant() == V) &&
+ "Marking constant with different value");
assert(isUndefined());
- Val.setInt(constant);
- assert(V && "Marking constant with NULL");
- Val.setPointer(V);
+ Tag = constant;
+ Val = V;
return true;
}
/// markNotConstant - Return true if this is a change in status.
bool markNotConstant(Constant *V) {
- if (isNotConstant()) {
- assert(getNotConstant() == V && "Marking !constant with different value");
+ assert(V && "Marking constant with NULL");
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
+ return markConstantRange(ConstantRange(CI->getValue()+1, CI->getValue()));
+ if (isa<UndefValue>(V))
return false;
+
+ assert((!isConstant() || getConstant() != V) &&
+ "Marking constant !constant with same value");
+ assert((!isNotConstant() || getNotConstant() == V) &&
+ "Marking !constant with different value");
+ assert(isUndefined() || isConstant());
+ Tag = notconstant;
+ Val = V;
+ return true;
+ }
+
+ /// markConstantRange - Return true if this is a change in status.
+ bool markConstantRange(const ConstantRange NewR) {
+ if (isConstantRange()) {
+ if (NewR.isEmptySet())
+ return markOverdefined();
+
+ bool changed = Range != NewR;
+ Range = NewR;
+ return changed;
}
- if (isConstant())
- assert(getConstant() != V && "Marking not constant with different value");
- else
- assert(isUndefined());
-
- Val.setInt(notconstant);
- assert(V && "Marking constant with NULL");
- Val.setPointer(V);
+ assert(isUndefined());
+ if (NewR.isEmptySet())
+ return markOverdefined();
+
+ Tag = constantrange;
+ Range = NewR;
return true;
}
if (RHS.isUndefined() || isOverdefined()) return false;
if (RHS.isOverdefined()) return markOverdefined();
- if (RHS.isNotConstant()) {
- if (isNotConstant()) {
- if (getNotConstant() != RHS.getNotConstant() ||
- isa<ConstantExpr>(getNotConstant()) ||
- isa<ConstantExpr>(RHS.getNotConstant()))
- return markOverdefined();
- return false;
+ if (isUndefined()) {
+ Tag = RHS.Tag;
+ Val = RHS.Val;
+ Range = RHS.Range;
+ return true;
+ }
+
+ if (isConstant()) {
+ if (RHS.isConstant()) {
+ if (Val == RHS.Val)
+ return false;
+ return markOverdefined();
}
- if (isConstant()) {
- if (getConstant() == RHS.getNotConstant() ||
- isa<ConstantExpr>(RHS.getNotConstant()) ||
- isa<ConstantExpr>(getConstant()))
+
+ if (RHS.isNotConstant()) {
+ if (Val == RHS.Val)
return markOverdefined();
- return markNotConstant(RHS.getNotConstant());
+
+ // Unless we can prove that the two Constants are different, we must
+ // move to overdefined.
+ // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding.
+ if (ConstantInt *Res = dyn_cast<ConstantInt>(
+ ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
+ getConstant(),
+ RHS.getNotConstant())))
+ if (Res->isOne())
+ return markNotConstant(RHS.getNotConstant());
+
+ return markOverdefined();
}
-
- assert(isUndefined() && "Unexpected lattice");
- return markNotConstant(RHS.getNotConstant());
+
+ // RHS is a ConstantRange, LHS is a non-integer Constant.
+
+ // FIXME: consider the case where RHS is a range [1, 0) and LHS is
+ // a function. The correct result is to pick up RHS.
+
+ return markOverdefined();
}
-
- // RHS must be a constant, we must be undef, constant, or notconstant.
- if (isUndefined())
- return markConstant(RHS.getConstant());
-
- if (isConstant()) {
- if (getConstant() != RHS.getConstant())
+
+ if (isNotConstant()) {
+ if (RHS.isConstant()) {
+ if (Val == RHS.Val)
+ return markOverdefined();
+
+ // Unless we can prove that the two Constants are different, we must
+ // move to overdefined.
+ // FIXME: use DataLayout/TargetLibraryInfo for smarter constant folding.
+ if (ConstantInt *Res = dyn_cast<ConstantInt>(
+ ConstantFoldCompareInstOperands(CmpInst::ICMP_NE,
+ getNotConstant(),
+ RHS.getConstant())))
+ if (Res->isOne())
+ return false;
+
return markOverdefined();
- return false;
+ }
+
+ if (RHS.isNotConstant()) {
+ if (Val == RHS.Val)
+ return false;
+ return markOverdefined();
+ }
+
+ return markOverdefined();
}
- // If we are known "!=4" and RHS is "==5", stay at "!=4".
- if (getNotConstant() == RHS.getConstant() ||
- isa<ConstantExpr>(getNotConstant()) ||
- isa<ConstantExpr>(RHS.getConstant()))
+ assert(isConstantRange() && "New LVILattice type?");
+ if (!RHS.isConstantRange())
return markOverdefined();
- return false;
+
+ ConstantRange NewR = Range.unionWith(RHS.getConstantRange());
+ if (NewR.isFullSet())
+ return markOverdefined();
+ return markConstantRange(NewR);
}
-
};
} // 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";
if (Val.isNotConstant())
return OS << "notconstant<" << *Val.getNotConstant() << '>';
+ else if (Val.isConstantRange())
+ return OS << "constantrange<" << Val.getConstantRange().getLower() << ", "
+ << Val.getConstantRange().getUpper() << '>';
return OS << "constant<" << *Val.getConstant() << '>';
}
}
//===----------------------------------------------------------------------===//
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:
- /// BlockCacheEntryTy - This is a computed lattice value at the end of the
- /// specified basic block for a Value* that depends on context.
- typedef std::pair<BasicBlock*, LVILatticeVal> BlockCacheEntryTy;
-
/// 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::vector<BlockCacheEntryTy> ValueCacheEntryTy;
+ typedef std::map<AssertingVH<BasicBlock>, LVILatticeVal> ValueCacheEntryTy;
- private:
/// ValueCache - This is all of the cached information for all values,
/// mapped from Value* to key information.
- DenseMap<Value*, ValueCacheEntryTy> ValueCache;
+ 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.
- DenseMap<BasicBlock*, std::set<Value*> > OverDefinedCache;
- public:
+ 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.
+ 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;
+ }
+ };
+
+
+ LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB);
+ bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T,
+ LVILatticeVal &Result,
+ Instruction *CxtI = nullptr);
+ bool hasBlockValue(Value *Val, BasicBlock *BB);
+
+ // These methods process one work item and may add more. A false value
+ // returned means that the work item was not completely processed and must
+ // be revisited after going through the new items.
+ bool solveBlockValue(Value *Val, BasicBlock *BB);
+ bool solveBlockValueNonLocal(LVILatticeVal &BBLV,
+ Value *Val, BasicBlock *BB);
+ bool solveBlockValuePHINode(LVILatticeVal &BBLV,
+ 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)];
+ }
+
+ 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
/// NewSucc.
void threadEdge(BasicBlock *PredBB,BasicBlock *OldSucc,BasicBlock *NewSucc);
- };
-} // end anonymous namespace
-
-namespace {
- struct BlockCacheEntryComparator {
- static int Compare(const void *LHSv, const void *RHSv) {
- const LazyValueInfoCache::BlockCacheEntryTy *LHS =
- static_cast<const LazyValueInfoCache::BlockCacheEntryTy *>(LHSv);
- const LazyValueInfoCache::BlockCacheEntryTy *RHS =
- static_cast<const LazyValueInfoCache::BlockCacheEntryTy *>(RHSv);
- if (LHS->first < RHS->first)
- return -1;
- if (LHS->first > RHS->first)
- return 1;
- return 0;
- }
- bool operator()(const LazyValueInfoCache::BlockCacheEntryTy &LHS,
- const LazyValueInfoCache::BlockCacheEntryTy &RHS) const {
- return LHS.first < RHS.first;
+ /// eraseBlock - This is part of the update interface to inform the cache
+ /// that a block has been deleted.
+ void eraseBlock(BasicBlock *BB);
+
+ /// 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 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);
+
+ // This erasure deallocates *this, so it MUST happen after we're done
+ // using any and all members of *this.
+ Parent->ValueCache.erase(*this);
}
-//===----------------------------------------------------------------------===//
-// LVIQuery Impl
-//===----------------------------------------------------------------------===//
+void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
+ // Shortcut if we have never seen this block.
+ DenseSet<AssertingVH<BasicBlock> >::iterator I = SeenBlocks.find(BB);
+ if (I == SeenBlocks.end())
+ return;
+ SeenBlocks.erase(I);
-namespace {
- /// LVIQuery - This is a transient object that exists while a query is
- /// being performed.
- ///
- /// TODO: Reuse LVIQuery instead of recreating it for every query, this avoids
- /// reallocation of the densemap on every query.
- class LVIQuery {
- typedef LazyValueInfoCache::BlockCacheEntryTy BlockCacheEntryTy;
- typedef LazyValueInfoCache::ValueCacheEntryTy ValueCacheEntryTy;
-
- /// This is the current value being queried for.
- Value *Val;
-
- /// This is all of the cached information about this value.
- ValueCacheEntryTy &Cache;
-
- /// This tracks, for each block, what values are overdefined.
- DenseMap<BasicBlock*, std::set<Value*> > &OverDefinedCache;
-
- /// NewBlocks - This is a mapping of the new BasicBlocks which have been
- /// added to cache but that are not in sorted order.
- DenseMap<BasicBlock*, LVILatticeVal> NewBlockInfo;
- public:
-
- LVIQuery(Value *V, ValueCacheEntryTy &VC,
- DenseMap<BasicBlock*, std::set<Value*> > &ODC)
- : Val(V), Cache(VC), OverDefinedCache(ODC) {
- }
+ 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);
+ }
- ~LVIQuery() {
- // When the query is done, insert the newly discovered facts into the
- // cache in sorted order.
- if (NewBlockInfo.empty()) return;
+ for (SmallVectorImpl<OverDefinedPairTy>::iterator I = ToErase.begin(),
+ E = ToErase.end(); I != E; ++I)
+ OverDefinedCache.erase(*I);
- // Grow the cache to exactly fit the new data.
- Cache.reserve(Cache.size() + NewBlockInfo.size());
-
- // If we only have one new entry, insert it instead of doing a full-on
- // sort.
- if (NewBlockInfo.size() == 1) {
- BlockCacheEntryTy Entry = *NewBlockInfo.begin();
- ValueCacheEntryTy::iterator I =
- std::lower_bound(Cache.begin(), Cache.end(), Entry,
- BlockCacheEntryComparator());
- assert((I == Cache.end() || I->first != Entry.first) &&
- "Entry already in map!");
-
- Cache.insert(I, Entry);
- return;
- }
-
- // TODO: If we only have two new elements, INSERT them both.
-
- Cache.insert(Cache.end(), NewBlockInfo.begin(), NewBlockInfo.end());
- array_pod_sort(Cache.begin(), Cache.end(),
- BlockCacheEntryComparator::Compare);
-
- for (DenseMap<BasicBlock*, LVILatticeVal>::iterator
- I = NewBlockInfo.begin(), E = NewBlockInfo.end(); I != E; ++I) {
- if (I->second.isOverdefined())
- OverDefinedCache[I->first].insert(Val);
- }
+ for (std::map<LVIValueHandle, ValueCacheEntryTy>::iterator
+ I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I)
+ I->second.erase(BB);
+}
+
+void LazyValueInfoCache::solve() {
+ while (!BlockValueStack.empty()) {
+ std::pair<BasicBlock*, Value*> &e = BlockValueStack.top();
+ if (solveBlockValue(e.second, e.first)) {
+ assert(BlockValueStack.top() == e);
+ BlockValueStack.pop();
}
+ }
+}
- LVILatticeVal getBlockValue(BasicBlock *BB);
- LVILatticeVal getEdgeValue(BasicBlock *FromBB, BasicBlock *ToBB);
+bool LazyValueInfoCache::hasBlockValue(Value *Val, BasicBlock *BB) {
+ // If already a constant, there is nothing to compute.
+ if (isa<Constant>(Val))
+ return true;
- private:
- LVILatticeVal &getCachedEntryForBlock(BasicBlock *BB);
- };
-} // end anonymous namespace
+ LVIValueHandle ValHandle(Val, this);
+ std::map<LVIValueHandle, ValueCacheEntryTy>::iterator I =
+ ValueCache.find(ValHandle);
+ if (I == ValueCache.end()) return false;
+ return I->second.count(BB);
+}
-/// getCachedEntryForBlock - See if we already have a value for this block. If
-/// so, return it, otherwise create a new entry in the NewBlockInfo map to use.
-LVILatticeVal &LVIQuery::getCachedEntryForBlock(BasicBlock *BB) {
-
- // Do a binary search to see if we already have an entry for this block in
- // the cache set. If so, find it.
- if (!Cache.empty()) {
- ValueCacheEntryTy::iterator Entry =
- std::lower_bound(Cache.begin(), Cache.end(),
- BlockCacheEntryTy(BB, LVILatticeVal()),
- BlockCacheEntryComparator());
- if (Entry != Cache.end() && Entry->first == BB)
- return Entry->second;
- }
-
- // Otherwise, check to see if it's in NewBlockInfo or create a new entry if
- // not.
- return NewBlockInfo[BB];
+LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) {
+ // If already a constant, there is nothing to compute.
+ if (Constant *VC = dyn_cast<Constant>(Val))
+ return LVILatticeVal::get(VC);
+
+ SeenBlocks.insert(BB);
+ return lookup(Val)[BB];
}
-LVILatticeVal LVIQuery::getBlockValue(BasicBlock *BB) {
- // See if we already have a value for this block.
- LVILatticeVal &BBLV = getCachedEntryForBlock(BB);
+bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
+ if (isa<Constant>(Val))
+ return true;
+
+ ValueCacheEntryTy &Cache = lookup(Val);
+ SeenBlocks.insert(BB);
+ LVILatticeVal &BBLV = Cache[BB];
- // If we've already computed this block's value, return it.
+ // 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 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 (!BBLV.isUndefined()) {
DEBUG(dbgs() << " reuse BB '" << BB->getName() << "' val=" << BBLV <<'\n');
- return BBLV;
+
+ // Since we're reusing a cached value here, we don't need to update the
+ // OverDefinedCache. The cache will have been properly updated
+ // whenever the cached value was inserted.
+ ODCacheUpdater.markResult(false);
+ return true;
}
// Otherwise, this is the first time we're seeing this block. Reset the
// conservatively correct.
BBLV.markOverdefined();
- // If V is live into BB, see if our predecessors know anything about it.
Instruction *BBI = dyn_cast<Instruction>(Val);
- if (BBI == 0 || BBI->getParent() != BB) {
- LVILatticeVal Result; // Start Undefined.
- unsigned NumPreds = 0;
-
- // Loop over all of our predecessors, merging what we know from them into
- // result.
- for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
- Result.mergeIn(getEdgeValue(*PI, BB));
-
- // If we hit overdefined, exit early. The BlockVals entry is already set
- // to overdefined.
- if (Result.isOverdefined()) {
- DEBUG(dbgs() << " compute BB '" << BB->getName()
- << "' - overdefined because of pred.\n");
- return Result;
+ if (!BBI || BBI->getParent() != BB) {
+ return ODCacheUpdater.markResult(solveBlockValueNonLocal(BBLV, Val, BB));
+ }
+
+ if (PHINode *PN = dyn_cast<PHINode>(BBI)) {
+ 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;
+ if ((!isa<BinaryOperator>(BBI) && !isa<CastInst>(BBI)) ||
+ !BBI->getType()->isIntegerTy()) {
+ DEBUG(dbgs() << " compute BB '" << BB->getName()
+ << "' - overdefined because inst def found.\n");
+ BBLV.markOverdefined();
+ return ODCacheUpdater.markResult(true);
+ }
+
+ // FIXME: We're currently limited to binops with a constant RHS. This should
+ // be improved.
+ BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI);
+ if (BO && !isa<ConstantInt>(BO->getOperand(1))) {
+ DEBUG(dbgs() << " compute BB '" << BB->getName()
+ << "' - overdefined because inst def found.\n");
+
+ BBLV.markOverdefined();
+ return ODCacheUpdater.markResult(true);
+ }
+
+ return ODCacheUpdater.markResult(solveBlockValueConstantRange(BBLV, BBI, BB));
+}
+
+static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) {
+ if (LoadInst *L = dyn_cast<LoadInst>(I)) {
+ return L->getPointerAddressSpace() == 0 &&
+ GetUnderlyingObject(L->getPointerOperand()) == Ptr;
+ }
+ if (StoreInst *S = dyn_cast<StoreInst>(I)) {
+ return S->getPointerAddressSpace() == 0 &&
+ 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;
+ }
+ return false;
+}
+
+bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
+ Value *Val, BasicBlock *BB) {
+ LVILatticeVal Result; // Start Undefined.
+
+ // If this is a pointer, and there's a load from that pointer in this BB,
+ // then we know that the pointer can't be NULL.
+ bool NotNull = false;
+ if (Val->getType()->isPointerTy()) {
+ 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;
+ }
+ }
}
- ++NumPreds;
}
-
- // If this is the entry block, we must be asking about an argument. The
- // value is overdefined.
- if (NumPreds == 0 && BB == &BB->getParent()->front()) {
- assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
+ }
+
+ // If this is the entry block, we must be asking about an argument. The
+ // value is overdefined.
+ if (BB == &BB->getParent()->getEntryBlock()) {
+ assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
+ if (NotNull) {
+ PointerType *PTy = cast<PointerType>(Val->getType());
+ Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
+ } else {
Result.markOverdefined();
- return Result;
}
-
- // Return the merged value, which is more precise than 'overdefined'.
- assert(!Result.isOverdefined());
- return getCachedEntryForBlock(BB) = Result;
+ BBLV = Result;
+ return true;
}
+
+ // Loop over all of our predecessors, merging what we know from them into
+ // result.
+ bool EdgesMissing = false;
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+ LVILatticeVal EdgeResult;
+ EdgesMissing |= !getEdgeValue(Val, *PI, BB, EdgeResult);
+ if (EdgesMissing)
+ continue;
+
+ Result.mergeIn(EdgeResult);
+
+ // If we hit overdefined, exit early. The BlockVals entry is already set
+ // to overdefined.
+ if (Result.isOverdefined()) {
+ DEBUG(dbgs() << " compute BB '" << BB->getName()
+ << "' - overdefined because of pred.\n");
+ // If we previously determined that this is a pointer that can't be null
+ // then return that rather than giving up entirely.
+ if (NotNull) {
+ PointerType *PTy = cast<PointerType>(Val->getType());
+ Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
+ }
+
+ BBLV = Result;
+ return true;
+ }
+ }
+ if (EdgesMissing)
+ return false;
+
+ // Return the merged value, which is more precise than 'overdefined'.
+ assert(!Result.isOverdefined());
+ BBLV = Result;
+ return true;
+}
- // If this value is defined by an instruction in this block, we have to
- // process it here somehow or return overdefined.
- if (PHINode *PN = dyn_cast<PHINode>(BBI)) {
- (void)PN;
- // TODO: PHI Translation in preds.
- } else {
-
+bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV,
+ PHINode *PN, BasicBlock *BB) {
+ LVILatticeVal Result; // Start Undefined.
+
+ // Loop over all of our predecessors, merging what we know from them into
+ // result.
+ bool EdgesMissing = false;
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+ BasicBlock *PhiBB = PN->getIncomingBlock(i);
+ Value *PhiVal = PN->getIncomingValue(i);
+ LVILatticeVal 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;
+
+ Result.mergeIn(EdgeResult);
+
+ // If we hit overdefined, exit early. The BlockVals entry is already set
+ // to overdefined.
+ if (Result.isOverdefined()) {
+ DEBUG(dbgs() << " compute BB '" << BB->getName()
+ << "' - overdefined because of pred.\n");
+
+ BBLV = Result;
+ return true;
+ }
+ }
+ if (EdgesMissing)
+ return false;
+
+ // Return the merged value, which is more precise than 'overdefined'.
+ assert(!Result.isOverdefined() && "Possible PHI in entry block?");
+ BBLV = Result;
+ 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)) {
+ 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;
}
- DEBUG(dbgs() << " compute BB '" << BB->getName()
- << "' - overdefined because inst def found.\n");
+ ConstantRange LHSRange = LHSVal.getConstantRange();
+ ConstantRange RHSRange(1);
+ IntegerType *ResultTy = cast<IntegerType>(BBI->getType());
+ if (isa<BinaryOperator>(BBI)) {
+ if (ConstantInt *RHS = dyn_cast<ConstantInt>(BBI->getOperand(1))) {
+ RHSRange = ConstantRange(RHS->getValue());
+ } else {
+ BBLV.markOverdefined();
+ return true;
+ }
+ }
+ // NOTE: We're currently limited by the set of operations that ConstantRange
+ // can evaluate symbolically. Enhancing that set will allows us to analyze
+ // more definitions.
LVILatticeVal Result;
- Result.markOverdefined();
- return getCachedEntryForBlock(BB) = Result;
+ switch (BBI->getOpcode()) {
+ case Instruction::Add:
+ Result.markConstantRange(LHSRange.add(RHSRange));
+ break;
+ case Instruction::Sub:
+ Result.markConstantRange(LHSRange.sub(RHSRange));
+ break;
+ case Instruction::Mul:
+ Result.markConstantRange(LHSRange.multiply(RHSRange));
+ break;
+ case Instruction::UDiv:
+ Result.markConstantRange(LHSRange.udiv(RHSRange));
+ break;
+ case Instruction::Shl:
+ Result.markConstantRange(LHSRange.shl(RHSRange));
+ break;
+ case Instruction::LShr:
+ Result.markConstantRange(LHSRange.lshr(RHSRange));
+ break;
+ case Instruction::Trunc:
+ Result.markConstantRange(LHSRange.truncate(ResultTy->getBitWidth()));
+ break;
+ case Instruction::SExt:
+ Result.markConstantRange(LHSRange.signExtend(ResultTy->getBitWidth()));
+ break;
+ case Instruction::ZExt:
+ Result.markConstantRange(LHSRange.zeroExtend(ResultTy->getBitWidth()));
+ break;
+ case Instruction::BitCast:
+ Result.markConstantRange(LHSRange);
+ break;
+ case Instruction::And:
+ Result.markConstantRange(LHSRange.binaryAnd(RHSRange));
+ break;
+ case Instruction::Or:
+ Result.markConstantRange(LHSRange.binaryOr(RHSRange));
+ break;
+
+ // Unhandled instructions are overdefined.
+ default:
+ DEBUG(dbgs() << " compute BB '" << BB->getName()
+ << "' - overdefined because inst def found.\n");
+ Result.markOverdefined();
+ break;
+ }
+
+ BBLV = Result;
+ 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)));
-/// getEdgeValue - This method attempts to infer more complex
-LVILatticeVal LVIQuery::getEdgeValue(BasicBlock *BBFrom, BasicBlock *BBTo) {
+ 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 V is the condition of the branch itself, then we know exactly what
// it is.
- if (BI->getCondition() == Val)
- return LVILatticeVal::get(ConstantInt::get(
- Type::getInt1Ty(Val->getContext()), isTrueDest));
+ if (BI->getCondition() == Val) {
+ Result = LVILatticeVal::get(ConstantInt::get(
+ Type::getInt1Ty(Val->getContext()), isTrueDest));
+ return true;
+ }
// If the condition of the branch is an equality comparison, we may be
// able to infer the value.
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition()))
- if (ICI->isEquality() && ICI->getOperand(0) == Val &&
- isa<Constant>(ICI->getOperand(1))) {
- // We know that V has the RHS constant if this is a true SETEQ or
- // false SETNE.
- if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
- return LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
- return LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
- }
+ ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition());
+ 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 BBTo is the default destination of the switch, we don't know anything.
- // Given a more powerful range analysis we could know stuff.
- if (SI->getCondition() == Val && SI->getDefaultDest() != BBTo) {
- // 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)
- return LVILatticeVal::get(EdgeVal);
+ 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);
}
+ Result = LVILatticeVal::getRange(EdgesVals);
+ return true;
}
-
- // Otherwise see if the value is known in the block.
- return getBlockValue(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.
+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;
-//===----------------------------------------------------------------------===//
-// LazyValueInfoCache Impl
-//===----------------------------------------------------------------------===//
+ // 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;
+ }
-LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB) {
- // If already a constant, there is nothing to compute.
- if (Constant *VC = dyn_cast<Constant>(V))
- return LVILatticeVal::get(VC);
-
+ // 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");
- LVILatticeVal Result = LVIQuery(V, ValueCache[V],
- OverDefinedCache).getBlockValue(BB);
-
+ 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) {
- // If already a constant, there is nothing to compute.
- if (Constant *VC = dyn_cast<Constant>(V))
- return LVILatticeVal::get(VC);
-
+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 =
- LVIQuery(V, ValueCache[V],
- OverDefinedCache).getEdgeValue(FromBB, ToBB);
-
+ LVILatticeVal Result;
+ if (!getEdgeValue(V, FromBB, ToBB, Result, CxtI)) {
+ solve();
+ bool WasFastQuery = getEdgeValue(V, FromBB, ToBB, Result, CxtI);
+ (void)WasFastQuery;
+ assert(WasFastQuery && "More work to do after problem solved?");
+ }
+
DEBUG(dbgs() << " Result = " << Result << "\n");
-
return Result;
}
// 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.
std::vector<BasicBlock*> worklist;
worklist.push_back(OldSucc);
- std::set<Value*> ClearSet = OverDefinedCache[OldSucc];
- LVILatticeVal OverDef;
- OverDef.markOverdefined();
+ DenseSet<Value*> ClearSet;
+ for (DenseSet<OverDefinedPairTy>::iterator I = OverDefinedCache.begin(),
+ E = OverDefinedCache.end(); I != E; ++I) {
+ if (I->first == OldSucc)
+ ClearSet.insert(I->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
if (ToUpdate == NewSucc) continue;
bool changed = false;
- std::set<Value*> &CurrentSet = OverDefinedCache[ToUpdate];
- for (std::set<Value*>::iterator I = ClearSet.begin(),E = ClearSet.end();
+ 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...
- if (CurrentSet.count(*I)) {
- // Remove it from the caches.
- ValueCacheEntryTy &Entry = ValueCache[*I];
- ValueCacheEntryTy::iterator CI =
- std::lower_bound(Entry.begin(), Entry.end(),
- std::make_pair(ToUpdate, OverDef),
- BlockCacheEntryComparator());
- assert(CI != Entry.end() && "Couldn't find entry to update?");
- Entry.erase(CI);
-
- CurrentSet.erase(*I);
-
- // If we removed anything, then we potentially need to update
- // blocks successors too.
- changed = true;
- }
+ DenseSet<OverDefinedPairTy>::iterator OI =
+ OverDefinedCache.find(std::make_pair(ToUpdate, *I));
+ if (OI == OverDefinedCache.end()) continue;
+
+ // Remove it from the caches.
+ ValueCacheEntryTy &Entry = ValueCache[LVIValueHandle(*I, this)];
+ ValueCacheEntryTy::iterator CI = Entry.find(ToUpdate);
+
+ assert(CI != Entry.end() && "Couldn't find entry to update?");
+ Entry.erase(CI);
+ OverDefinedCache.erase(OI);
+
+ // If we removed anything, then we potentially need to update
+ // blocks successors too.
+ changed = true;
}
-
+
if (!changed) continue;
worklist.insert(worklist.end(), succ_begin(ToUpdate), succ_end(ToUpdate));
// LazyValueInfo Impl
//===----------------------------------------------------------------------===//
+/// getCache - This lazily constructs the LazyValueInfoCache.
+static LazyValueInfoCache &getCache(void *&PImpl,
+ AssumptionTracker *AT,
+ const DataLayout *DL = nullptr,
+ DominatorTree *DT = nullptr) {
+ if (!PImpl)
+ PImpl = new LazyValueInfoCache(AT, DL, DT);
+ return *static_cast<LazyValueInfoCache*>(PImpl);
+}
+
bool LazyValueInfo::runOnFunction(Function &F) {
- TD = getAnalysisIfAvailable<TargetData>();
+ 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, AT, DL, DT).clear();
+
// Fully lazy.
return false;
}
-/// getCache - This lazily constructs the LazyValueInfoCache.
-static LazyValueInfoCache &getCache(void *&PImpl) {
- if (!PImpl)
- PImpl = new LazyValueInfoCache();
- return *static_cast<LazyValueInfoCache*>(PImpl);
+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();
- return 0;
+ if (Result.isConstantRange()) {
+ ConstantRange CR = Result.getConstantRange();
+ if (const APInt *SingleVal = CR.getSingleElement())
+ return ConstantInt::get(V->getContext(), *SingleVal);
+ }
+ 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();
- return 0;
+ if (Result.isConstantRange()) {
+ ConstantRange CR = Result.getConstantRange();
+ if (const APInt *SingleVal = CR.getSingleElement())
+ return ConstantInt::get(V->getContext(), *SingleVal);
+ }
+ 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);
- if (ConstantInt *ResCI = dyn_cast_or_null<ConstantInt>(Res))
- return ResCI->isZero() ? False : True;
- return Unknown;
+ Res = ConstantFoldCompareInstOperands(Pred, Result.getConstant(), C, DL,
+ TLI);
+ if (ConstantInt *ResCI = dyn_cast<ConstantInt>(Res))
+ return ResCI->isZero() ? LazyValueInfo::False : LazyValueInfo::True;
+ return LazyValueInfo::Unknown;
+ }
+
+ if (Result.isConstantRange()) {
+ ConstantInt *CI = dyn_cast<ConstantInt>(C);
+ if (!CI) return LazyValueInfo::Unknown;
+
+ ConstantRange CR = Result.getConstantRange();
+ if (Pred == ICmpInst::ICMP_EQ) {
+ if (!CR.contains(CI->getValue()))
+ return LazyValueInfo::False;
+
+ if (CR.isSingleElement() && CR.contains(CI->getValue()))
+ return LazyValueInfo::True;
+ } else if (Pred == ICmpInst::ICMP_NE) {
+ if (!CR.contains(CI->getValue()))
+ return LazyValueInfo::True;
+
+ if (CR.isSingleElement() && CR.contains(CI->getValue()))
+ return LazyValueInfo::False;
+ }
+
+ // Handle more complex predicates.
+ ConstantRange TrueValues =
+ ICmpInst::makeConstantRange((ICmpInst::Predicate)Pred, CI->getValue());
+ if (TrueValues.contains(CR))
+ return LazyValueInfo::True;
+ if (TrueValues.inverse().contains(CR))
+ 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) {
- getCache(PImpl).threadEdge(PredBB, OldSucc, NewSucc);
+ BasicBlock *NewSucc) {
+ if (PImpl) getCache(PImpl, AT, DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
+}
+
+void LazyValueInfo::eraseBlock(BasicBlock *BB) {
+ if (PImpl) getCache(PImpl, AT, DL, DT).eraseBlock(BB);
}
projects / oota-llvm.git / blobdiff