diff --git a/unsupported/test/special_packetmath.cpp b/unsupported/test/special_packetmath.cpp
index 1a53a09ff..57f00d5af 100644
--- a/unsupported/test/special_packetmath.cpp
+++ b/unsupported/test/special_packetmath.cpp
@@ -33,9 +33,9 @@ void packetmath_real() {
   const int PacketSize = internal::unpacket_traits<Packet>::size;
 
   const int size = PacketSize * 4;
-  EIGEN_ALIGN_MAX Scalar data1[PacketSize * 4];
-  EIGEN_ALIGN_MAX Scalar data2[PacketSize * 4];
-  EIGEN_ALIGN_MAX Scalar ref[PacketSize * 4];
+  EIGEN_ALIGN_MAX Scalar data1[PacketSize * 4] = {};
+  EIGEN_ALIGN_MAX Scalar data2[PacketSize * 4] = {};
+  EIGEN_ALIGN_MAX Scalar ref[PacketSize * 4] = {};
 
 #if EIGEN_HAS_C99_MATH
   {