diff options
Diffstat (limited to 'lib/Analysis/LazyValueInfo.cpp')
| -rw-r--r-- | lib/Analysis/LazyValueInfo.cpp | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp index b4923f9a71..e32dbc4447 100644 --- a/lib/Analysis/LazyValueInfo.cpp +++ b/lib/Analysis/LazyValueInfo.cpp @@ -452,14 +452,15 @@ LVILatticeVal LVIQuery::getBlockValue(BasicBlock *BB) { // 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()) { - const PointerType *PTy = cast<PointerType>(Val->getType()); for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();BI != BE;++BI){ LoadInst *L = dyn_cast<LoadInst>(BI); if (L && L->getPointerAddressSpace() == 0 && L->getPointerOperand()->getUnderlyingObject() == Val->getUnderlyingObject()) { - return LVILatticeVal::getNot(ConstantPointerNull::get(PTy)); + NotNull = true; + break; } } } @@ -475,11 +476,19 @@ LVILatticeVal LVIQuery::getBlockValue(BasicBlock *BB) { 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) { + const PointerType *PTy = cast<PointerType>(Val->getType()); + Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy)); + } + return Result; } ++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()) { |