[PATCH] D130155: [DRAFT] [DeadStoreElimination] Handle null accessing

[Chuanqi Xu via Phabricator via llvm-commits]

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After we landed https://reviews.llvm.org/D127383, the compiler may crash due to it tries to access a may-null value. This is because https://github.com/llvm/llvm-project/blob/051738b08cf5e39fd274dd379147d1c19e2b5b20/llvm/lib/Analysis/MemoryLocation.cpp#L121-L122 may return null after we land D127383 <https://reviews.llvm.org/D127383>.


https://reviews.llvm.org/D130155

Files:
  llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp


Index: llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -1925,10 +1925,12 @@
         if (auto *MemSetI = dyn_cast<MemSetInst>(UpperInst)) {
           if (auto *SI = dyn_cast<StoreInst>(DefInst)) {
             // MemSetInst must have a write location.
-            MemoryLocation UpperLoc = *getLocForWrite(UpperInst);
+            Optional<MemoryLocation> UpperLoc = getLocForWrite(UpperInst);
+            if (!UpperLoc)
+              return false;
             int64_t InstWriteOffset = 0;
             int64_t DepWriteOffset = 0;
-            auto OR = isOverwrite(UpperInst, DefInst, UpperLoc, *MaybeDefLoc,
+            auto OR = isOverwrite(UpperInst, DefInst, *UpperLoc, *MaybeDefLoc,
                                   InstWriteOffset, DepWriteOffset);
             Value *StoredByte = isBytewiseValue(SI->getValueOperand(), DL);
             return StoredByte && StoredByte == MemSetI->getOperand(1) &&


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