diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 0d17ef773f44c..adf86526ebf14 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -933,8 +933,8 @@ void ObjCARCOpt::OptimizeIndividualCallImpl(Function &F, Instruction *Inst,
     if (IsNullOrUndef(CI->getArgOperand(0))) {
       Changed = true;
       new StoreInst(ConstantInt::getTrue(CI->getContext()),
-                    UndefValue::get(Type::getInt1PtrTy(CI->getContext())), CI);
-      Value *NewValue = UndefValue::get(CI->getType());
+                    PoisonValue::get(Type::getInt1PtrTy(CI->getContext())), CI);
+      Value *NewValue = PoisonValue::get(CI->getType());
       LLVM_DEBUG(
           dbgs() << "A null pointer-to-weak-pointer is undefined behavior."
                     "\nOld = "
@@ -952,9 +952,9 @@ void ObjCARCOpt::OptimizeIndividualCallImpl(Function &F, Instruction *Inst,
         IsNullOrUndef(CI->getArgOperand(1))) {
       Changed = true;
       new StoreInst(ConstantInt::getTrue(CI->getContext()),
-                    UndefValue::get(Type::getInt1PtrTy(CI->getContext())), CI);
+                    PoisonValue::get(Type::getInt1PtrTy(CI->getContext())), CI);
 
-      Value *NewValue = UndefValue::get(CI->getType());
+      Value *NewValue = PoisonValue::get(CI->getType());
       LLVM_DEBUG(
           dbgs() << "A null pointer-to-weak-pointer is undefined behavior."
                     "\nOld = "
diff --git a/llvm/test/Transforms/ObjCARC/weak.ll b/llvm/test/Transforms/ObjCARC/weak.ll
index ad5ac571f06ca..db63847c8f6c9 100644
--- a/llvm/test/Transforms/ObjCARC/weak.ll
+++ b/llvm/test/Transforms/ObjCARC/weak.ll
@@ -14,24 +14,24 @@ declare void @llvm.objc.copyWeak(ptr, ptr)
 define void @test0(ptr %p, ptr %q) {
 ; CHECK-LABEL: @test0(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
-; CHECK-NEXT:    store i1 true, ptr undef, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
+; CHECK-NEXT:    store i1 true, ptr poison, align 1
 ; CHECK-NEXT:    ret void
 ;
 entry: