diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/GVN.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GVN.cpp | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index 1522dbab47d..fe4c03a7518 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -1004,27 +1004,24 @@ bool GVN::processLoad(LoadInst *L, DenseMap<Value*, LoadInst*> &lastLoad, toErase.push_back(L); deletedLoad = true; NumGVNLoad++; - break; } else { dep = MD.getDependencyFrom(L, DepInst, DepInst->getParent()); } } - if (AllocationInst *DepAI = dyn_cast_or_null<AllocationInst>(dep.getInst())) { - // Check that this load is actually from the - // allocation we found - if (L->getOperand(0)->getUnderlyingObject() == DepAI) { - // If this load depends directly on an allocation, there isn't - // anything stored there; therefore, we can optimize this load - // to undef. - MD.removeInstruction(L); - - L->replaceAllUsesWith(UndefValue::get(L->getType())); - toErase.push_back(L); - deletedLoad = true; - NumGVNLoad++; - } + // If this load really doesn't depend on anything, then we must be loading an + // undef value. This can happen when loading for a fresh allocation with no + // intervening stores, for example. + if (dep.isNone()) { + // If this load depends directly on an allocation, there isn't + // anything stored there; therefore, we can optimize this load + // to undef. + MD.removeInstruction(L); + L->replaceAllUsesWith(UndefValue::get(L->getType())); + toErase.push_back(L); + deletedLoad = true; + NumGVNLoad++; } if (!deletedLoad) |
