diff --git a/src/compiler/backend/instruction-selector.cc b/src/compiler/backend/instruction-selector.cc
index 626065df94..923562dbd9 100644
--- a/src/compiler/backend/instruction-selector.cc
+++ b/src/compiler/backend/instruction-selector.cc
@@ -752,16 +752,14 @@ size_t InstructionSelector::AddInputsToFrameStateDescriptor(
     FrameStateDescriptor* descriptor, FrameState state, OperandGenerator* g,
     StateObjectDeduplicator* deduplicator, InstructionOperandVector* inputs,
     FrameStateInputKind kind, Zone* zone) {
-  DCHECK_EQ(IrOpcode::kFrameState, state->op()->opcode());
-
   size_t entries = 0;
   size_t initial_size = inputs->size();
   USE(initial_size);  // initial_size is only used for debug.
 
   if (descriptor->outer_state()) {
     entries += AddInputsToFrameStateDescriptor(
-        descriptor->outer_state(), state.outer_frame_state(), g, deduplicator,
-        inputs, kind, zone);
+        descriptor->outer_state(), FrameState{state.outer_frame_state()}, g,
+        deduplicator, inputs, kind, zone);
   }
 
   Node* parameters = state.parameters();
@@ -3343,9 +3341,9 @@ FrameStateDescriptor* GetFrameStateDescriptorInternal(Zone* zone,
   int stack = state_info.type() == FrameStateType::kUnoptimizedFunction ? 1 : 0;
 
   FrameStateDescriptor* outer_state = nullptr;
-  if (state.has_outer_frame_state()) {
-    outer_state =
-        GetFrameStateDescriptorInternal(zone, state.outer_frame_state());
+  if (state.outer_frame_state()->opcode() == IrOpcode::kFrameState) {
+    outer_state = GetFrameStateDescriptorInternal(
+        zone, FrameState{state.outer_frame_state()});
   }
 
 #if V8_ENABLE_WEBASSEMBLY
diff --git a/src/compiler/common-operator.h b/src/compiler/common-operator.h
index a0b26a7298..4ec8f38f5e 100644
--- a/src/compiler/common-operator.h
+++ b/src/compiler/common-operator.h
@@ -617,12 +617,7 @@ class CommonNodeWrapperBase : public NodeWrapper {
 class FrameState : public CommonNodeWrapperBase {
  public:
   explicit constexpr FrameState(Node* node) : CommonNodeWrapperBase(node) {
-    // TODO(jgruber): Disallow kStart (needed for PromiseConstructorBasic unit
-    // test, among others). Also, outer_frame_state points at the start node
-    // for non-inlined functions. This could be avoided by checking
-    // has_outer_frame_state() before casting to FrameState.
-    DCHECK(node->opcode() == IrOpcode::kFrameState ||
-           node->opcode() == IrOpcode::kStart);
+    DCHECK_EQ(node->opcode(), IrOpcode::kFrameState);
   }
 
   FrameStateInfo frame_state_info() const {
@@ -657,15 +652,13 @@ class FrameState : public CommonNodeWrapperBase {
   Node* function() const { return node()->InputAt(kFrameStateFunctionInput); }
 
   // An outer frame state exists for inlined functions; otherwise it points at
-  // the start node.
-  bool has_outer_frame_state() const {
-    Node* maybe_outer_frame_state = node()->InputAt(kFrameStateOuterStateInput);
-    DCHECK(maybe_outer_frame_state->opcode() == IrOpcode::kFrameState ||
-           maybe_outer_frame_state->opcode() == IrOpcode::kStart);
-    return maybe_outer_frame_state->opcode() == IrOpcode::kFrameState;
-  }
-  FrameState outer_frame_state() const {
-    return FrameState{node()->InputAt(kFrameStateOuterStateInput)};
+  // the start node. Could also be dead.
+  Node* outer_frame_state() const {
+    Node* result = node()->InputAt(kFrameStateOuterStateInput);
+    DCHECK(result->opcode() == IrOpcode::kFrameState ||
+           result->opcode() == IrOpcode::kStart ||
+           result->opcode() == IrOpcode::kDeadValue);
+    return result;
   }
 };
 
diff --git a/src/compiler/graph-assembler.cc b/src/compiler/graph-assembler.cc
index 7770da9ed6..020f6032c5 100644
--- a/src/compiler/graph-assembler.cc
+++ b/src/compiler/graph-assembler.cc
@@ -861,11 +861,11 @@ Node* GraphAssembler::DynamicCheckMapsWithDeoptUnless(Node* condition,
                                                       Node* value, Node* map,
                                                       Node* feedback_vector,
                                                       FrameState frame_state) {
-  return AddNode(graph()->NewNode(common()->DynamicCheckMapsWithDeoptUnless(
-                                      frame_state.has_outer_frame_state()),
-                                  condition, slot_index, value, map,
-                                  feedback_vector, frame_state, effect(),
-                                  control()));
+  return AddNode(graph()->NewNode(
+      common()->DynamicCheckMapsWithDeoptUnless(
+          frame_state.outer_frame_state()->opcode() == IrOpcode::kFrameState),
+      condition, slot_index, value, map, feedback_vector, frame_state, effect(),
+      control()));
 }
 
 TNode<Object> GraphAssembler::Call(const CallDescriptor* call_descriptor,
diff --git a/src/compiler/js-call-reducer.cc b/src/compiler/js-call-reducer.cc
index 682bd18a61..2acd96acc9 100644
--- a/src/compiler/js-call-reducer.cc
+++ b/src/compiler/js-call-reducer.cc
@@ -4072,7 +4072,7 @@ JSCallReducer::ReduceCallOrConstructWithArrayLikeOrSpreadOfCreateArguments(
       arraylike_or_spread_index - JSCallOrConstructNode::FirstArgumentIndex();
   // Check if are spreading to inlined arguments or to the arguments of
   // the outermost function.
-  if (!frame_state.has_outer_frame_state()) {
+  if (frame_state.outer_frame_state()->opcode() != IrOpcode::kFrameState) {
     Operator const* op;
     if (IsCallWithArrayLikeOrSpread(node)) {
       static constexpr int kTargetAndReceiver = 2;
@@ -4087,10 +4087,10 @@ JSCallReducer::ReduceCallOrConstructWithArrayLikeOrSpreadOfCreateArguments(
     NodeProperties::ChangeOp(node, op);
     return Changed(node);
   }
-  FrameState outer_state = frame_state.outer_frame_state();
   // Get to the actual frame state from which to extract the arguments;
   // we can only optimize this in case the {node} was already inlined into
   // some other function (and same for the {arg_array}).
+  FrameState outer_state{frame_state.outer_frame_state()};
   FrameStateInfo outer_info = outer_state.frame_state_info();
   if (outer_info.type() == FrameStateType::kArgumentsAdaptor) {
     // Need to take the parameters from the arguments adaptor.
diff --git a/src/compiler/js-create-lowering.cc b/src/compiler/js-create-lowering.cc
index 4b23ad59f3..c44de1ac01 100644
--- a/src/compiler/js-create-lowering.cc
+++ b/src/compiler/js-create-lowering.cc
@@ -156,7 +156,7 @@ Reduction JSCreateLowering::ReduceJSCreateArguments(Node* node) {
 
   // Use the ArgumentsAccessStub for materializing both mapped and unmapped
   // arguments object, but only for non-inlined (i.e. outermost) frames.
-  if (!frame_state.has_outer_frame_state()) {
+  if (frame_state.outer_frame_state()->opcode() != IrOpcode::kFrameState) {
     switch (type) {
       case CreateArgumentsType::kMappedArguments: {
         // TODO(turbofan): Duplicate parameters are not handled yet.
diff --git a/src/compiler/js-generic-lowering.cc b/src/compiler/js-generic-lowering.cc
index 3956d778a4..cc5d6aa69c 100644
--- a/src/compiler/js-generic-lowering.cc
+++ b/src/compiler/js-generic-lowering.cc
@@ -283,7 +283,7 @@ void JSGenericLowering::LowerJSLoadProperty(Node* node) {
   JSLoadPropertyNode n(node);
   const PropertyAccess& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 2);
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -307,7 +307,7 @@ void JSGenericLowering::LowerJSLoadNamed(Node* node) {
   JSLoadNamedNode n(node);
   NamedAccess const& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 1);
   if (!p.feedback().IsValid()) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -365,7 +365,7 @@ void JSGenericLowering::LowerJSLoadGlobal(Node* node) {
   const LoadGlobalParameters& p = n.Parameters();
   CallDescriptor::Flags flags = FrameStateFlagForCall(node);
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 0);
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -412,7 +412,7 @@ void JSGenericLowering::LowerJSStoreProperty(Node* node) {
   JSStorePropertyNode n(node);
   const PropertyAccess& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 3);
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -430,7 +430,7 @@ void JSGenericLowering::LowerJSStoreNamed(Node* node) {
   JSStoreNamedNode n(node);
   NamedAccess const& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 2);
   if (!p.feedback().IsValid()) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -455,7 +455,7 @@ void JSGenericLowering::LowerJSStoreNamedOwn(Node* node) {
   CallDescriptor::Flags flags = FrameStateFlagForCall(node);
   StoreNamedOwnParameters const& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 2);
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     n->RemoveInput(n.FeedbackVectorIndex());
@@ -477,7 +477,7 @@ void JSGenericLowering::LowerJSStoreGlobal(Node* node) {
   JSStoreGlobalNode n(node);
   const StoreGlobalParameters& p = n.Parameters();
   FrameState frame_state = n.frame_state();
-  FrameState outer_state = frame_state.outer_frame_state();
+  Node* outer_state = frame_state.outer_frame_state();
   STATIC_ASSERT(n.FeedbackVectorIndex() == 1);
   if (outer_state->opcode() != IrOpcode::kFrameState) {
     n->RemoveInput(n.FeedbackVectorIndex());
diff --git a/src/compiler/js-inlining.cc b/src/compiler/js-inlining.cc
index 02c8340281..150e409651 100644
--- a/src/compiler/js-inlining.cc
+++ b/src/compiler/js-inlining.cc
@@ -497,9 +497,9 @@ Reduction JSInliner::ReduceJSCall(Node* node) {
   // To ensure inlining always terminates, we have an upper limit on inlining
   // the nested calls.
   int nesting_level = 0;
-  for (FrameState frame_state = FrameState{call.frame_state()};
+  for (Node* frame_state = call.frame_state();
        frame_state->opcode() == IrOpcode::kFrameState;
-       frame_state = frame_state.outer_frame_state()) {
+       frame_state = FrameState{frame_state}.outer_frame_state()) {
     nesting_level++;
     if (nesting_level > kMaxDepthForInlining) {
       TRACE("Not inlining "
diff --git a/test/unittests/compiler/js-call-reducer-unittest.cc b/test/unittests/compiler/js-call-reducer-unittest.cc
index e077638257..9a69dce916 100644
--- a/test/unittests/compiler/js-call-reducer-unittest.cc
+++ b/test/unittests/compiler/js-call-reducer-unittest.cc
@@ -120,6 +120,14 @@ class JSCallReducerTest : public TypedGraphTest {
                               CallFeedbackRelation::kTarget);
   }
 
+  Node* DummyFrameState() {
+    return graph()->NewNode(
+        common()->FrameState(BytecodeOffset{42},
+                             OutputFrameStateCombine::Ignore(), nullptr),
+        graph()->start(), graph()->start(), graph()->start(), graph()->start(),
+        graph()->start(), graph()->start());
+  }
+
  private:
   JSOperatorBuilder javascript_;
   CompilationDependencies deps_;
@@ -131,7 +139,7 @@ TEST_F(JSCallReducerTest, PromiseConstructorNoArgs) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
 
   Node* construct = graph()->NewNode(
@@ -151,7 +159,7 @@ TEST_F(JSCallReducerTest, PromiseConstructorSubclass) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
 
   Node* executor = UndefinedConstant();
@@ -170,7 +178,7 @@ TEST_F(JSCallReducerTest, PromiseConstructorBasic) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
 
   Node* executor = UndefinedConstant();
@@ -190,7 +198,7 @@ TEST_F(JSCallReducerTest, PromiseConstructorWithHook) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
 
   Node* executor = UndefinedConstant();
@@ -223,7 +231,7 @@ TEST_F(JSCallReducerTest, MathUnaryWithNumber) {
     Node* effect = graph()->start();
     Node* control = graph()->start();
     Node* context = UndefinedConstant();
-    Node* frame_state = graph()->start();
+    Node* frame_state = DummyFrameState();
     Node* jsfunction = MathFunction(fnc);
     Node* p0 = Parameter(Type::Any(), 0);
     Node* feedback = UndefinedConstant();
@@ -253,7 +261,7 @@ TEST_F(JSCallReducerTest, MathBinaryWithNumber) {
     Node* effect = graph()->start();
     Node* control = graph()->start();
     Node* context = UndefinedConstant();
-    Node* frame_state = graph()->start();
+    Node* frame_state = DummyFrameState();
     Node* p0 = Parameter(Type::Any(), 0);
     Node* p1 = Parameter(Type::Any(), 0);
     Node* feedback = UndefinedConstant();
@@ -276,7 +284,7 @@ TEST_F(JSCallReducerTest, MathClz32WithUnsigned32) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
 
   Node* p0 = Parameter(Type::Unsigned32(), 0);
   Node* feedback = UndefinedConstant();
@@ -295,7 +303,7 @@ TEST_F(JSCallReducerTest, MathClz32WithUnsigned32NoArg) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
 
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -316,7 +324,7 @@ TEST_F(JSCallReducerTest, MathImulWithUnsigned32) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Unsigned32(), 0);
   Node* p1 = Parameter(Type::Unsigned32(), 1);
   Node* feedback = UndefinedConstant();
@@ -338,7 +346,7 @@ TEST_F(JSCallReducerTest, MathMinWithNoArguments) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
   Node* call =
       graph()->NewNode(Call(0), jsfunction, UndefinedConstant(), feedback,
@@ -354,7 +362,7 @@ TEST_F(JSCallReducerTest, MathMinWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -371,7 +379,7 @@ TEST_F(JSCallReducerTest, MathMinWithTwoArguments) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* p1 = Parameter(Type::Any(), 1);
   Node* feedback = UndefinedConstant();
@@ -394,7 +402,7 @@ TEST_F(JSCallReducerTest, MathMaxWithNoArguments) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* feedback = UndefinedConstant();
   Node* call =
       graph()->NewNode(Call(0), jsfunction, UndefinedConstant(), feedback,
@@ -410,7 +418,7 @@ TEST_F(JSCallReducerTest, MathMaxWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -428,7 +436,7 @@ TEST_F(JSCallReducerTest, MathMaxWithTwoArguments) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* p1 = Parameter(Type::Any(), 1);
   Node* feedback = UndefinedConstant();
@@ -451,7 +459,7 @@ TEST_F(JSCallReducerTest, StringFromSingleCharCodeWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -470,7 +478,7 @@ TEST_F(JSCallReducerTest, StringFromSingleCharCodeWithPlainPrimitive) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::PlainPrimitive(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -492,7 +500,7 @@ TEST_F(JSCallReducerTest, NumberIsFinite) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -513,7 +521,7 @@ TEST_F(JSCallReducerTest, NumberIsIntegerWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -534,7 +542,7 @@ TEST_F(JSCallReducerTest, NumberIsNaNWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -555,7 +563,7 @@ TEST_F(JSCallReducerTest, NumberIsSafeIntegerWithIntegral32) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -576,7 +584,7 @@ TEST_F(JSCallReducerTest, GlobalIsFiniteWithNumber) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -597,7 +605,7 @@ TEST_F(JSCallReducerTest, GlobalIsNaN) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* feedback = UndefinedConstant();
   Node* call =
@@ -618,7 +626,7 @@ TEST_F(JSCallReducerTest, NumberParseInt) {
   Node* effect = graph()->start();
   Node* control = graph()->start();
   Node* context = UndefinedConstant();
-  Node* frame_state = graph()->start();
+  Node* frame_state = DummyFrameState();
   Node* p0 = Parameter(Type::Any(), 0);
   Node* p1 = Parameter(Type::Any(), 1);
   Node* feedback = UndefinedConstant();