[DSE][NFC] Clean up DeadStoreElimination from unused variables

[xgupta]

Oh wow, there are some dead code in dead code elimination pass :)

Should be fine to commit if failed premerge checks are not related to this patch.

[yurai007]

Thanks for approval. I think premerge failures are unrelated to this change. Similar libarcher/openmp errors can be seen in many other reviews for couple weeks.

[fhahn]

LGTM, thanks!

llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp

LLVM_DEBUG(
         dbgs()
         << "Trying to eliminate MemoryDefs at the end of the function\n");
     for (int I = MemDefs.size() - 1; I >= 0; I--) {
       MemoryDef *Def = MemDefs[I];
       if (SkipStores.contains(Def) || !isRemovable(Def->getMemoryInst()))
         continue;
 
       Instruction *DefI = Def->getMemoryInst();
-      SmallVector<const Value *, 4> Pointers;
       auto DefLoc = getLocForWriteEx(DefI);
       if (!DefLoc)
         continue;
 
       // NOTE: Currently eliminating writes at the end of a function is limited
       // to MemoryDefs with a single underlying object, to save compile-time. In
       // practice it appears the case with multiple underlying objects is very
       // uncommon. If it turns out to be important, we can use
for (int I = MemDefs.size() - 1; I >= 0; I--) {
         MadeChange = true;
       }
     }
     return MadeChange;
   }
 
   /// \returns true if \p Def is a no-op store, either because it
   /// directly stores back a loaded value or stores zero to a calloced object.
-  bool storeIsNoop(MemoryDef *Def, const MemoryLocation &DefLoc,
-                   const Value *DefUO) {
+  bool storeIsNoop(MemoryDef *Def, const Value *DefUO) {
     StoreInst *Store = dyn_cast<StoreInst>(Def->getMemoryInst());
     MemSetInst *MemSet = dyn_cast<MemSetInst>(Def->getMemoryInst());
     Constant *StoredConstant = nullptr;
     if (Store)
       StoredConstant = dyn_cast<Constant>(Store->getOperand(0));
     if (MemSet)
       StoredConstant = dyn_cast<Constant>(MemSet->getValue());
 
for (unsigned I = 0; I < ToCheck.size(); I++) {
           ++NumFastStores;
           MadeChange = true;
         }
       }
     }
 
     // Check if the store is a no-op.
     if (!Shortend && isRemovable(SI) &&
-        State.storeIsNoop(KillingDef, SILoc, SILocUnd)) {
+        State.storeIsNoop(KillingDef, SILocUnd)) {
       LLVM_DEBUG(dbgs() << "DSE: Remove No-Op Store:\n  DEAD: " << *SI << '\n');
       State.deleteDeadInstruction(SI);
       NumRedundantStores++;
       MadeChange = true;
       continue;
     }
   }