diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
index 26d765f47907f..43c798f6879e5 100644
--- a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
+++ b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift
@@ -256,7 +256,7 @@ private extension Deallocation {
 
 private extension DeallocStackInst {
   func isStackDeallocation(of base: AccessBase) -> Bool {
-    if case .stack(let allocStack) = base, allocstack == allocStack {
+    if case .stack(let allocStack) = base, operand.value == allocStack {
       return true
     }
     return false
diff --git a/SwiftCompilerSources/Sources/SIL/Instruction.swift b/SwiftCompilerSources/Sources/SIL/Instruction.swift
index 9b4ccbd8b0a4d..e0f8749af38db 100644
--- a/SwiftCompilerSources/Sources/SIL/Instruction.swift
+++ b/SwiftCompilerSources/Sources/SIL/Instruction.swift
@@ -647,11 +647,7 @@ extension Deallocation {
 }
 
 
-final public class DeallocStackInst : Instruction, UnaryInstruction, Deallocation {
-  public var allocstack: AllocStackInst {
-    return operand.value as! AllocStackInst
-  }
-}
+final public class DeallocStackInst : Instruction, UnaryInstruction, Deallocation {}
 
 final public class DeallocStackRefInst : Instruction, UnaryInstruction, Deallocation {
   public var allocRef: AllocRefInstBase { operand.value as! AllocRefInstBase }