X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FMemoryDependenceAnalysis.cpp;h=8f22b0ed3de3dd6dfd99ee49430ed9ea8d698715;hb=6238162cc518a915aba296ddda24311d4974290f;hp=015ded18d900a0626f567e8b80bb08f5371e8a7a;hpb=f4ccd110750a3f3fe6a107d5c74c649c2a0dc407;p=oota-llvm.git diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index 015ded18d90..8f22b0ed3de 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -14,7 +14,6 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "memdep" #include "llvm/Analysis/MemoryDependenceAnalysis.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/Statistic.h" @@ -33,6 +32,8 @@ #include "llvm/Support/Debug.h" using namespace llvm; +#define DEBUG_TYPE "memdep" + STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses"); STATISTIC(NumCacheDirtyNonLocal, "Number of dirty cached non-local responses"); STATISTIC(NumUncacheNonLocal, "Number of uncached non-local responses"); @@ -88,10 +89,10 @@ void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { bool MemoryDependenceAnalysis::runOnFunction(Function &) { AA = &getAnalysis(); DataLayoutPass *DLP = getAnalysisIfAvailable(); - DL = DLP ? &DLP->getDataLayout() : 0; + DL = DLP ? &DLP->getDataLayout() : nullptr; DominatorTreeWrapperPass *DTWP = getAnalysisIfAvailable(); - DT = DTWP ? &DTWP->getDomTree() : 0; + DT = DTWP ? &DTWP->getDomTree() : nullptr; if (!PredCache) PredCache.reset(new PredIteratorCache()); return false; @@ -157,29 +158,32 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst, return AliasAnalysis::Mod; } - if (const IntrinsicInst *II = dyn_cast(Inst)) + if (const IntrinsicInst *II = dyn_cast(Inst)) { + AAMDNodes AAInfo; + switch (II->getIntrinsicID()) { case Intrinsic::lifetime_start: case Intrinsic::lifetime_end: case Intrinsic::invariant_start: + II->getAAMetadata(AAInfo); Loc = AliasAnalysis::Location(II->getArgOperand(1), cast(II->getArgOperand(0)) - ->getZExtValue(), - II->getMetadata(LLVMContext::MD_tbaa)); + ->getZExtValue(), AAInfo); // These intrinsics don't really modify the memory, but returning Mod // will allow them to be handled conservatively. return AliasAnalysis::Mod; case Intrinsic::invariant_end: + II->getAAMetadata(AAInfo); Loc = AliasAnalysis::Location(II->getArgOperand(2), cast(II->getArgOperand(1)) - ->getZExtValue(), - II->getMetadata(LLVMContext::MD_tbaa)); + ->getZExtValue(), AAInfo); // These intrinsics don't really modify the memory, but returning Mod // will allow them to be handled conservatively. return AliasAnalysis::Mod; default: break; } + } // Otherwise, just do the coarse-grained thing that always works. if (Inst->mayWriteToMemory()) @@ -261,10 +265,10 @@ isLoadLoadClobberIfExtendedToFullWidth(const AliasAnalysis::Location &MemLoc, const LoadInst *LI, const DataLayout *DL) { // If we have no target data, we can't do this. - if (DL == 0) return false; + if (!DL) return false; // If we haven't already computed the base/offset of MemLoc, do so now. - if (MemLocBase == 0) + if (!MemLocBase) MemLocBase = GetPointerBaseWithConstantOffset(MemLoc.Ptr, MemLocOffs, DL); unsigned Size = MemoryDependenceAnalysis:: @@ -362,13 +366,13 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, BasicBlock::iterator ScanIt, BasicBlock *BB, Instruction *QueryInst) { - const Value *MemLocBase = 0; + const Value *MemLocBase = nullptr; int64_t MemLocOffset = 0; unsigned Limit = BlockScanLimit; bool isInvariantLoad = false; if (isLoad && QueryInst) { LoadInst *LI = dyn_cast(QueryInst); - if (LI && LI->getMetadata(LLVMContext::MD_invariant_load) != 0) + if (LI && LI->getMetadata(LLVMContext::MD_invariant_load) != nullptr) isInvariantLoad = true; } @@ -403,10 +407,31 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // Values depend on loads if the pointers are must aliased. This means that // a load depends on another must aliased load from the same value. + // One exception is atomic loads: a value can depend on an atomic load that it + // does not alias with when this atomic load indicates that another thread may + // be accessing the location. if (LoadInst *LI = dyn_cast(Inst)) { // Atomic loads have complications involved. + // A monotonic load is OK if the query inst is itself not atomic. // FIXME: This is overly conservative. - if (!LI->isUnordered()) + if (!LI->isUnordered()) { + if (!QueryInst) + return MemDepResult::getClobber(LI); + if (LI->getOrdering() != Monotonic) + return MemDepResult::getClobber(LI); + if (auto *QueryLI = dyn_cast(QueryInst)) + if (!QueryLI->isSimple()) + return MemDepResult::getClobber(LI); + if (auto *QuerySI = dyn_cast(QueryInst)) + if (!QuerySI->isSimple()) + return MemDepResult::getClobber(LI); + } + + // FIXME: this is overly conservative. + // While volatile access cannot be eliminated, they do not have to clobber + // non-aliasing locations, as normal accesses can for example be reordered + // with volatile accesses. + if (LI->isVolatile()) return MemDepResult::getClobber(LI); AliasAnalysis::Location LoadLoc = AA->getLocation(LI); @@ -465,8 +490,26 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, if (StoreInst *SI = dyn_cast(Inst)) { // Atomic stores have complications involved. + // A monotonic store is OK if the query inst is itself not atomic. // FIXME: This is overly conservative. - if (!SI->isUnordered()) + if (!SI->isUnordered()) { + if (!QueryInst) + return MemDepResult::getClobber(SI); + if (SI->getOrdering() != Monotonic) + return MemDepResult::getClobber(SI); + if (auto *QueryLI = dyn_cast(QueryInst)) + if (!QueryLI->isSimple()) + return MemDepResult::getClobber(SI); + if (auto *QuerySI = dyn_cast(QueryInst)) + if (!QuerySI->isSimple()) + return MemDepResult::getClobber(SI); + } + + // FIXME: this is overly conservative. + // While volatile access cannot be eliminated, they do not have to clobber + // non-aliasing locations, as normal accesses can for example be reordered + // with volatile accesses. + if (SI->isVolatile()) return MemDepResult::getClobber(SI); // If alias analysis can tell that this store is guaranteed to not modify @@ -696,7 +739,7 @@ MemoryDependenceAnalysis::getNonLocalCallDependency(CallSite QueryCS) { if (Entry != Cache.begin() && std::prev(Entry)->getBB() == DirtyBB) --Entry; - NonLocalDepEntry *ExistingResult = 0; + NonLocalDepEntry *ExistingResult = nullptr; if (Entry != Cache.begin()+NumSortedEntries && Entry->getBB() == DirtyBB) { // If we already have an entry, and if it isn't already dirty, the block @@ -807,7 +850,7 @@ GetNonLocalInfoForBlock(const AliasAnalysis::Location &Loc, if (Entry != Cache->begin() && (Entry-1)->getBB() == BB) --Entry; - NonLocalDepEntry *ExistingResult = 0; + NonLocalDepEntry *ExistingResult = nullptr; if (Entry != Cache->begin()+NumSortedEntries && Entry->getBB() == BB) ExistingResult = &*Entry; @@ -921,10 +964,10 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // Set up a temporary NLPI value. If the map doesn't yet have an entry for // CacheKey, this value will be inserted as the associated value. Otherwise, // it'll be ignored, and we'll have to check to see if the cached size and - // tbaa tag are consistent with the current query. + // aa tags are consistent with the current query. NonLocalPointerInfo InitialNLPI; InitialNLPI.Size = Loc.Size; - InitialNLPI.TBAATag = Loc.TBAATag; + InitialNLPI.AATags = Loc.AATags; // Get the NLPI for CacheKey, inserting one into the map if it doesn't // already have one. @@ -954,21 +997,21 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, SkipFirstBlock); } - // If the query's TBAATag is inconsistent with the cached one, + // If the query's AATags are inconsistent with the cached one, // conservatively throw out the cached data and restart the query with // no tag if needed. - if (CacheInfo->TBAATag != Loc.TBAATag) { - if (CacheInfo->TBAATag) { + if (CacheInfo->AATags != Loc.AATags) { + if (CacheInfo->AATags) { CacheInfo->Pair = BBSkipFirstBlockPair(); - CacheInfo->TBAATag = 0; + CacheInfo->AATags = AAMDNodes(); for (NonLocalDepInfo::iterator DI = CacheInfo->NonLocalDeps.begin(), DE = CacheInfo->NonLocalDeps.end(); DI != DE; ++DI) if (Instruction *Inst = DI->getResult().getInst()) RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey); CacheInfo->NonLocalDeps.clear(); } - if (Loc.TBAATag) - return getNonLocalPointerDepFromBB(Pointer, Loc.getWithoutTBAATag(), + if (Loc.AATags) + return getNonLocalPointerDepFromBB(Pointer, Loc.getWithoutAATags(), isLoad, StartBB, Result, Visited, SkipFirstBlock); } @@ -1116,7 +1159,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, SortNonLocalDepInfoCache(*Cache, NumSortedEntries); NumSortedEntries = Cache->size(); } - Cache = 0; + Cache = nullptr; PredList.clear(); for (BasicBlock **PI = PredCache->GetPreds(BB); *PI; ++PI) { @@ -1126,7 +1169,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // Get the PHI translated pointer in this predecessor. This can fail if // not translatable, in which case the getAddr() returns null. PHITransAddr &PredPointer = PredList.back().second; - PredPointer.PHITranslateValue(BB, Pred, 0); + PredPointer.PHITranslateValue(BB, Pred, nullptr); Value *PredPtrVal = PredPointer.getAddr(); @@ -1175,7 +1218,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // predecessor, then we have to assume that the pointer is clobbered in // that predecessor. We can still do PRE of the load, which would insert // a computation of the pointer in this predecessor. - if (PredPtrVal == 0) + if (!PredPtrVal) CanTranslate = false; // FIXME: it is entirely possible that PHI translating will end up with @@ -1224,7 +1267,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer, // for the given block. It assumes that we haven't modified any of // our datastructures while processing the current block. - if (Cache == 0) { + if (!Cache) { // Refresh the CacheInfo/Cache pointer if it got invalidated. CacheInfo = &NonLocalPointerDeps[CacheKey]; Cache = &CacheInfo->NonLocalDeps; @@ -1279,7 +1322,7 @@ RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair P) { for (unsigned i = 0, e = PInfo.size(); i != e; ++i) { Instruction *Target = PInfo[i].getResult().getInst(); - if (Target == 0) continue; // Ignore non-local dep results. + if (!Target) continue; // Ignore non-local dep results. assert(Target->getParent() == PInfo[i].getBB()); // Eliminating the dirty entry from 'Cache', so update the reverse info.