diff --git a/benchmarks/bin/binary_decode_packed.dart b/benchmarks/bin/binary_decode_packed.dart
index 5e4d3e35..f640cca4 100644
--- a/benchmarks/bin/binary_decode_packed.dart
+++ b/benchmarks/bin/binary_decode_packed.dart
@@ -146,13 +146,35 @@ class PackedEnumDecodingBenchmark extends BenchmarkBase {
   PackedEnumDecodingBenchmark() : super('PackedEnumDecoding') {
     final rand = Random(123);
     final message = PackedFields();
-    final numEnums = Enum.values.length;
+    final numEnums = Enum1.values.length;
     for (var i = 0; i < 1000000; i += 1) {
-      message.packedEnum.add(Enum.values[rand.nextInt(numEnums)]);
+      message.packedEnum1.add(Enum1.values[rand.nextInt(numEnums)]);
     }
     encoded = message.writeToBuffer();
   }
 
+  @override
+  void setup() {
+    // Decode different enums to prevent TFA from specializing enum decoding
+    // code to one type.
+    final rand = Random(123);
+    final message = PackedFields();
+    for (var i = 0; i < 100; i += 1) {
+      message.packedEnum1.add(Enum1.values[rand.nextInt(Enum1.values.length)]);
+    }
+    for (var i = 0; i < 100; i += 1) {
+      message.packedEnum2.add(Enum2.values[rand.nextInt(Enum2.values.length)]);
+    }
+    final encoded = message.writeToBuffer();
+    final decoded = PackedFields()..mergeFromBuffer(encoded);
+    if (decoded.packedEnum1.length != 100) {
+      throw AssertionError('BUG');
+    }
+    if (decoded.packedEnum2.length != 100) {
+      throw AssertionError('BUG');
+    }
+  }
+
   @override
   void run() {
     sink = PackedFields()..mergeFromBuffer(encoded);
diff --git a/benchmarks/protos/packed_fields.proto b/benchmarks/protos/packed_fields.proto
index 2e4f9451..09d32d3b 100644
--- a/benchmarks/protos/packed_fields.proto
+++ b/benchmarks/protos/packed_fields.proto
@@ -8,13 +8,22 @@ message PackedFields {
     repeated sint32 packedSint32 = 5 [packed = true];
     repeated sint64 packedSint64 = 6 [packed = true];
     repeated bool packedBool = 7 [packed = true];
-    repeated Enum packedEnum = 8 [packed = true];
+    repeated Enum1 packedEnum1 = 8 [packed = true];
+    repeated Enum2 packedEnum2 = 9 [packed = true];
 }
 
-enum Enum {
-  ENUM_1 = 0;
-  ENUM_2 = 1;
-  ENUM_3 = 2;
-  ENUM_4 = 4;
-  ENUM_5 = 5;
+enum Enum1 {
+  ENUM_1_1 = 0;
+  ENUM_1_2 = 1;
+  ENUM_1_3 = 2;
+  ENUM_1_4 = 4;
+  ENUM_1_5 = 5;
+}
+
+enum Enum2 {
+  ENUM_2_1 = 0;
+  ENUM_2_2 = 1;
+  ENUM_2_3 = 2;
+  ENUM_2_4 = 4;
+  ENUM_2_5 = 5;
 }