diff options
Diffstat (limited to 'llvm/lib/Analysis/MemoryDependenceAnalysis.cpp')
| -rw-r--r-- | llvm/lib/Analysis/MemoryDependenceAnalysis.cpp | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp index 8fdca0b..ab29393 100644 --- a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -407,7 +407,6 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // 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. - bool HasSeenAcquire = false; if (isLoad && QueryInst) { LoadInst *LI = dyn_cast<LoadInst>(QueryInst); @@ -468,12 +467,12 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // Atomic loads have complications involved. // A Monotonic (or higher) load is OK if the query inst is itself not atomic. - // An Acquire (or higher) load sets the HasSeenAcquire flag, so that any - // release store will know to return getClobber. // FIXME: This is overly conservative. if (LI->isAtomic() && LI->getOrdering() > Unordered) { if (!QueryInst) return MemDepResult::getClobber(LI); + if (LI->getOrdering() != Monotonic) + return MemDepResult::getClobber(LI); if (auto *QueryLI = dyn_cast<LoadInst>(QueryInst)) { if (!QueryLI->isSimple()) return MemDepResult::getClobber(LI); @@ -483,9 +482,6 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, } else if (QueryInst->mayReadOrWriteMemory()) { return MemDepResult::getClobber(LI); } - - if (isAtLeastAcquire(LI->getOrdering())) - HasSeenAcquire = true; } AliasAnalysis::Location LoadLoc = AA->getLocation(LI); @@ -545,12 +541,12 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { // Atomic stores have complications involved. // A Monotonic store is OK if the query inst is itself not atomic. - // A Release (or higher) store further requires that no acquire load - // has been seen. // FIXME: This is overly conservative. if (!SI->isUnordered()) { if (!QueryInst) return MemDepResult::getClobber(SI); + if (SI->getOrdering() != Monotonic) + return MemDepResult::getClobber(SI); if (auto *QueryLI = dyn_cast<LoadInst>(QueryInst)) { if (!QueryLI->isSimple()) return MemDepResult::getClobber(SI); @@ -560,9 +556,6 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, } else if (QueryInst->mayReadOrWriteMemory()) { return MemDepResult::getClobber(SI); } - - if (HasSeenAcquire && isAtLeastRelease(SI->getOrdering())) - return MemDepResult::getClobber(SI); } // FIXME: this is overly conservative. |