if (!Limit)
return MemDepResult::getUnknown();
- Instruction *Inst = --ScanIt;
+ Instruction *Inst = &*--ScanIt;
// If this inst is a memory op, get the pointer it accessed
MemoryLocation Loc;
const MemoryLocation &MemLoc, bool isLoad, BasicBlock::iterator ScanIt,
BasicBlock *BB, Instruction *QueryInst) {
+ if (QueryInst != nullptr) {
+ if (auto *LI = dyn_cast<LoadInst>(QueryInst)) {
+ MemDepResult invariantGroupDependency =
+ getInvariantGroupPointerDependency(LI, BB);
+
+ if (invariantGroupDependency.isDef())
+ return invariantGroupDependency;
+ }
+ }
+ return getSimplePointerDependencyFrom(MemLoc, isLoad, ScanIt, BB, QueryInst);
+}
+
+MemDepResult
+MemoryDependenceAnalysis::getInvariantGroupPointerDependency(LoadInst *LI,
+ BasicBlock *BB) {
+ Value *LoadOperand = LI->getPointerOperand();
+ // It's is not safe to walk the use list of global value, because function
+ // passes aren't allowed to look outside their functions.
+ if (isa<GlobalValue>(LoadOperand))
+ return MemDepResult::getUnknown();
+
+ auto *InvariantGroupMD = LI->getMetadata(LLVMContext::MD_invariant_group);
+ if (!InvariantGroupMD)
+ return MemDepResult::getUnknown();
+
+ MemDepResult Result = MemDepResult::getUnknown();
+ llvm::SmallSet<Value *, 14> Seen;
+ // Queue to process all pointers that are equivalent to load operand.
+ llvm::SmallVector<Value *, 8> LoadOperandsQueue;
+ LoadOperandsQueue.push_back(LoadOperand);
+ while (!LoadOperandsQueue.empty()) {
+ Value *Ptr = LoadOperandsQueue.pop_back_val();
+ if (isa<GlobalValue>(Ptr))
+ continue;
+
+ if (auto *BCI = dyn_cast<BitCastInst>(Ptr)) {
+ if (!Seen.count(BCI->getOperand(0))) {
+ LoadOperandsQueue.push_back(BCI->getOperand(0));
+ Seen.insert(BCI->getOperand(0));
+ }
+ }
+
+ for (Use &Us : Ptr->uses()) {
+ auto *U = dyn_cast<Instruction>(Us.getUser());
+ if (!U || U == LI || !DT->dominates(U, LI))
+ continue;
+
+ if (auto *BCI = dyn_cast<BitCastInst>(U)) {
+ if (!Seen.count(BCI)) {
+ LoadOperandsQueue.push_back(BCI);
+ Seen.insert(BCI);
+ }
+ continue;
+ }
+ // If we hit load/store with the same invariant.group metadata (and the
+ // same pointer operand) we can assume that value pointed by pointer
+ // operand didn't change.
+ if ((isa<LoadInst>(U) || isa<StoreInst>(U)) && U->getParent() == BB &&
+ U->getMetadata(LLVMContext::MD_invariant_group) == InvariantGroupMD)
+ return MemDepResult::getDef(U);
+ }
+ }
+ return Result;
+}
+
+MemDepResult MemoryDependenceAnalysis::getSimplePointerDependencyFrom(
+ const MemoryLocation &MemLoc, bool isLoad, BasicBlock::iterator ScanIt,
+ BasicBlock *BB, Instruction *QueryInst) {
+
const Value *MemLocBase = nullptr;
int64_t MemLocOffset = 0;
unsigned Limit = BlockScanLimit;
// being 42. A key property of this program however is that if either
// 1 or 4 were missing, there would be a race between the store of 42
// either the store of 0 or the load (making the whole progam racy).
- // The paper mentionned above shows that the same property is respected
+ // The paper mentioned above shows that the same property is respected
// by every program that can detect any optimisation of that kind: either
// it is racy (undefined) or there is a release followed by an acquire
// between the pair of accesses under consideration.
// Walk backwards through the basic block, looking for dependencies.
while (ScanIt != BB->begin()) {
- Instruction *Inst = --ScanIt;
+ Instruction *Inst = &*--ScanIt;
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst))
// Debug intrinsics don't (and can't) cause dependencies.
return MemDepResult::getDef(Inst);
if (isInvariantLoad)
continue;
- // Be conservative if the accessed pointer may alias the allocation.
- if (AA->alias(Inst, AccessPtr) != NoAlias)
- return MemDepResult::getClobber(Inst);
- // If the allocation is not aliased and does not read memory (like
- // strdup), it is safe to ignore.
- if (isa<AllocaInst>(Inst) ||
- isMallocLikeFn(Inst, TLI) || isCallocLikeFn(Inst, TLI))
+ // Be conservative if the accessed pointer may alias the allocation -
+ // fallback to the generic handling below.
+ if ((AA->alias(Inst, AccessPtr) == NoAlias) &&
+ // If the allocation is not aliased and does not read memory (like
+ // strdup), it is safe to ignore.
+ (isa<AllocaInst>(Inst) || isMallocLikeFn(Inst, TLI) ||
+ isCallocLikeFn(Inst, TLI)))
continue;
}
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(QueryInst))
isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_start;
- LocalCache = getPointerDependencyFrom(MemLoc, isLoad, ScanPos,
- QueryParent, QueryInst);
+ LocalCache = getPointerDependencyFrom(
+ MemLoc, isLoad, ScanPos->getIterator(), QueryParent, QueryInst);
} else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
CallSite QueryCS(QueryInst);
bool isReadOnly = AA->onlyReadsMemory(QueryCS);
- LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos,
- QueryParent);
+ LocalCache = getCallSiteDependencyFrom(
+ QueryCS, isReadOnly, ScanPos->getIterator(), QueryParent);
} else
// Non-memory instruction.
LocalCache = MemDepResult::getUnknown();
static void AssertSorted(MemoryDependenceAnalysis::NonLocalDepInfo &Cache,
int Count = -1) {
if (Count == -1) Count = Cache.size();
- if (Count == 0) return;
-
- for (unsigned i = 1; i != unsigned(Count); ++i)
- assert(!(Cache[i] < Cache[i-1]) && "Cache isn't sorted!");
+ assert(std::is_sorted(Cache.begin(), Cache.begin() + Count) &&
+ "Cache isn't sorted!");
}
#endif
BasicBlock::iterator ScanPos = DirtyBB->end();
if (ExistingResult) {
if (Instruction *Inst = ExistingResult->getResult().getInst()) {
- ScanPos = Inst;
+ ScanPos = Inst->getIterator();
// We're removing QueryInst's use of Inst.
RemoveFromReverseMap(ReverseNonLocalDeps, Inst,
QueryCS.getInstruction());
assert(ExistingResult->getResult().getInst()->getParent() == BB &&
"Instruction invalidated?");
++NumCacheDirtyNonLocalPtr;
- ScanPos = ExistingResult->getResult().getInst();
+ ScanPos = ExistingResult->getResult().getInst()->getIterator();
// Eliminating the dirty entry from 'Cache', so update the reverse info.
ValueIsLoadPair CacheKey(Loc.Ptr, isLoad);
- RemoveFromReverseMap(ReverseNonLocalPtrDeps, ScanPos, CacheKey);
+ RemoveFromReverseMap(ReverseNonLocalPtrDeps, &*ScanPos, CacheKey);
} else {
++NumUncacheNonLocalPtr;
}
// the entire block to get to this point.
MemDepResult NewDirtyVal;
if (!RemInst->isTerminator())
- NewDirtyVal = MemDepResult::getDirty(++BasicBlock::iterator(RemInst));
+ NewDirtyVal = MemDepResult::getDirty(&*++RemInst->getIterator());
ReverseDepMapType::iterator ReverseDepIt = ReverseLocalDeps.find(RemInst);
if (ReverseDepIt != ReverseLocalDeps.end()) {
projects / oota-llvm.git / blobdiff