commit ae5733346f0cc86a82c19fcdc50ce8232fa4777a
Author: Arthur Eubanks <aeubanks@google.com>
Date:   Thu Oct 6 10:29:46 2022 -0700

    Revert "[DSE] Eliminate noop store even through has clobbering between LoadI and StoreI"
    
    This reverts commit cd8f3e75813995c1d2da35370ffcf5af3aff9c2f.
    
    Causes miscompiles, see D132657

diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index 0036020dd6ee..93abda04bd8f 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -1874,23 +1874,8 @@ struct DSEState {
           // We are searching for the definition of the store's destination.
           // So, if that is the same definition as the load, then this is a
           // noop. Otherwise, fail.
-          if (LoadAccess != Current) {
-            // This is a potentially clobbering store, but it writes the same
-            // value, so we can safely ignore it if alignment is as expected.
-            if (auto *CurrentDef = cast<MemoryDef>(Current))
-              if (auto *CurrentStoreI =
-                      dyn_cast_or_null<StoreInst>(CurrentDef->getMemoryInst()))
-                // Check alignment to ensure load or store does not access at an
-                // offset.
-                if (CurrentStoreI->getValueOperand() == LoadI) {
-                  TypeSize StoreSize = DL.getTypeStoreSize(LoadI->getType());
-                  if (!StoreSize.isScalable() &&
-                      std::min(CurrentStoreI->getAlign(), LoadI->getAlign()) >=
-                          StoreSize)
-                    continue;
-                }
+          if (LoadAccess != Current)
             return false;
-          }
         }
         return true;
       }