[turbofan] Don't expect framestate input to be a Framestate

It could also be a DeadValue.

A regression test will take a while but the fix is straightforward.

Bug: chromium:1027045
Change-Id: I49a66668b7189b7ea7d6d79d514b9e0de3edc966
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1928853
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65094}

src/compiler/checkpoint-elimination.cc

@@ -19,7 +19,9 @@ namespace {
 FrameStateFunctionInfo const* GetFunctionInfo(Node* checkpoint) {
   DCHECK_EQ(IrOpcode::kCheckpoint, checkpoint->opcode());
   Node* frame_state = NodeProperties::GetFrameStateInput(checkpoint);
-  return FrameStateInfoOf(frame_state->op()).function_info();
+  return frame_state->opcode() == IrOpcode::kFrameState
+             ? FrameStateInfoOf(frame_state->op()).function_info()
+             : nullptr;
 }
 
 // The given checkpoint is redundant if it is effect-wise dominated by another
@@ -35,6 +37,7 @@ FrameStateFunctionInfo const* GetFunctionInfo(Node* checkpoint) {
 // exists. See regress-9945-*.js and v8:9945.
 bool IsRedundantCheckpoint(Node* node) {
   FrameStateFunctionInfo const* function_info = GetFunctionInfo(node);
+  if (function_info == nullptr) return false;
   Node* effect = NodeProperties::GetEffectInput(node);
   while (effect->op()->HasProperty(Operator::kNoWrite) &&
          effect->op()->EffectInputCount() == 1) {

test/unittests/compiler/graph-unittest.cc

@@ -90,9 +90,13 @@ Node* GraphTest::UndefinedConstant() {
 Node* GraphTest::EmptyFrameState() {
   Node* state_values =
       graph()->NewNode(common()->StateValues(0, SparseInputMask::Dense()));
+  FrameStateFunctionInfo const* function_info =
+      common()->CreateFrameStateFunctionInfo(
+          FrameStateType::kInterpretedFunction, 0, 0,
+          Handle<SharedFunctionInfo>());
   return graph()->NewNode(
       common()->FrameState(BailoutId::None(), OutputFrameStateCombine::Ignore(),
-                           nullptr),
+                           function_info),
       state_values, state_values, state_values, NumberConstant(0),
       UndefinedConstant(), graph()->start());
 }