diff --git a/src/objects/js-objects.cc b/src/objects/js-objects.cc
index 58d616ed98..4ba6ee9d83 100644
--- a/src/objects/js-objects.cc
+++ b/src/objects/js-objects.cc
@@ -4985,6 +4985,17 @@ void JSFunction::EnsureFeedbackVector(Handle<JSFunction> function) {
 // static
 void JSFunction::InitializeFeedbackCell(Handle<JSFunction> function) {
   Isolate* const isolate = function->GetIsolate();
+
+  if (function->has_feedback_vector()) {
+    // TODO(984344): Make this a CHECK that feedback vectors are identical to
+    // what we expect once we have removed all bytecode generation differences
+    // between eager and lazy compilation. For now just reset if they aren't
+    // identical
+    FeedbackVector vector = function->feedback_vector();
+    if (vector.length() == vector.metadata().slot_count()) return;
+    function->raw_feedback_cell().reset();
+  }
+
   bool needs_feedback_vector = !FLAG_lazy_feedback_allocation;
   // We need feedback vector for certain log events, collecting type profile
   // and more precise code coverage.
diff --git a/test/mjsunit/regress/regress-crbug-984344.js b/test/mjsunit/regress/regress-crbug-984344.js
new file mode 100644
index 0000000000..fea2c2d642
--- /dev/null
+++ b/test/mjsunit/regress/regress-crbug-984344.js
@@ -0,0 +1,34 @@
+// Copyright 2019 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --allow-natives-syntax
+
+function largeAllocToTriggerGC() {
+  for (let i = 0; i < 16; i++) {
+    let ab = new ArrayBuffer(1024 * 1024 * 10);
+  }
+}
+
+function foo() {
+  eval('function bar(a) {}' +
+       '(function() {' +
+       '  for (let c = 0; c < 505; c++) {' +
+       '    while (Promise >= 0xDEADBEEF) {' +
+       '      Array.prototype.slice.call(bar, bar, bar);' +
+       '    }' +
+       '    for (let i = 0; i < 413; i++) {' +
+       '    }' +
+       '  }' +
+       '})();' +
+       'largeAllocToTriggerGC();');
+}
+
+
+foo();
+foo();
+foo();
+// Don't prepare until here to allow function to be flushed.
+%PrepareFunctionForOptimization(foo);
+%OptimizeFunctionOnNextCall(foo);
+foo();