diff --git a/Eigen/Core b/Eigen/Core
index 1a9b4700b..1e7e38cb1 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -186,7 +186,6 @@ using std::ptrdiff_t;
 // Generic half float support
 #include "src/Core/arch/Default/Half.h"
 #include "src/Core/arch/Default/BFloat16.h"
-#include "src/Core/arch/Default/TypeCasting.h"
 #include "src/Core/arch/Default/GenericPacketMathFunctionsFwd.h"
 
 #if defined EIGEN_VECTORIZE_AVX512
diff --git a/Eigen/src/Core/CoreEvaluators.h b/Eigen/src/Core/CoreEvaluators.h
index e233efba1..32371c55b 100644
--- a/Eigen/src/Core/CoreEvaluators.h
+++ b/Eigen/src/Core/CoreEvaluators.h
@@ -621,6 +621,207 @@ protected:
   Data m_d;
 };
 
+// ----------------------- Casting ---------------------
+
+template <typename SrcType, typename DstType, typename ArgType>
+struct unary_evaluator<CwiseUnaryOp<core_cast_op<SrcType, DstType>, ArgType>, IndexBased> {
+  using CastOp = core_cast_op<SrcType, DstType>;
+  using XprType = CwiseUnaryOp<CastOp, ArgType>;
+
+  // Use the largest packet type by default
+  using SrcPacketType = typename packet_traits<SrcType>::type;
+  static constexpr int SrcPacketSize = unpacket_traits<SrcPacketType>::size;
+  static constexpr int SrcPacketBytes = SrcPacketSize * sizeof(SrcType);
+
+  enum {
+    CoeffReadCost = int(evaluator<ArgType>::CoeffReadCost) + int(functor_traits<CastOp>::Cost),
+    PacketAccess = functor_traits<CastOp>::PacketAccess,
+    ActualPacketAccessBit = PacketAccess ? PacketAccessBit : 0,
+    Flags = evaluator<ArgType>::Flags & (HereditaryBits | LinearAccessBit | ActualPacketAccessBit),
+    IsRowMajor = (evaluator<ArgType>::Flags & RowMajorBit),
+    Alignment = evaluator<ArgType>::Alignment
+  };
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE explicit unary_evaluator(const XprType& xpr)
+      : m_argImpl(xpr.nestedExpression()), m_rows(xpr.rows()), m_cols(xpr.cols()) {
+    EIGEN_INTERNAL_CHECK_COST_VALUE(functor_traits<CastOp>::Cost);
+    EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
+  }
+
+  template <typename DstPacketType>
+  using AltSrcScalarOp = std::enable_if_t<(unpacket_traits<DstPacketType>::size < SrcPacketSize && !find_packet_by_size<SrcType, unpacket_traits<DstPacketType>::size>::value), bool>;
+  template <typename DstPacketType>
+  using SrcPacketArgs1 = std::enable_if_t<(find_packet_by_size<SrcType, unpacket_traits<DstPacketType>::size>::value), bool>;
+  template <typename DstPacketType>
+  using SrcPacketArgs2 = std::enable_if_t<(unpacket_traits<DstPacketType>::size) == (2 * SrcPacketSize), bool>;
+  template <typename DstPacketType>
+  using SrcPacketArgs4 = std::enable_if_t<(unpacket_traits<DstPacketType>::size) == (4 * SrcPacketSize), bool>;
+  template <typename DstPacketType>
+  using SrcPacketArgs8 = std::enable_if_t<(unpacket_traits<DstPacketType>::size) == (8 * SrcPacketSize), bool>;
+
+  template <bool UseRowMajor = IsRowMajor, std::enable_if_t<UseRowMajor, bool> = true>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool check_array_bounds(Index, Index col, Index packetSize) const {
+    return col + packetSize <= cols();
+  }
+  template <bool UseRowMajor = IsRowMajor, std::enable_if_t<!UseRowMajor, bool> = true>
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool check_array_bounds(Index row, Index, Index packetSize) const {
+    return row + packetSize <= rows();
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool check_array_bounds(Index index, Index packetSize) const {
+    return index + packetSize <= size();
+  }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE SrcType srcCoeff(Index row, Index col, Index offset) const {
+    Index actualRow = IsRowMajor ? row : row + offset;
+    Index actualCol = IsRowMajor ? col + offset : col;
+    return m_argImpl.coeff(actualRow, actualCol);
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE SrcType srcCoeff(Index index, Index offset) const {
+    Index actualIndex = index + offset;
+    return m_argImpl.coeff(actualIndex);
+  }
+
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE DstType coeff(Index row, Index col) const {
+    return cast<SrcType, DstType>(srcCoeff(row, col, 0));
+  }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE DstType coeff(Index index) const { return cast<SrcType, DstType>(srcCoeff(index, 0)); }
+
+  template <int LoadMode, typename PacketType = SrcPacketType>
+  EIGEN_STRONG_INLINE PacketType srcPacket(Index row, Index col, Index offset) const {
+    constexpr int PacketSize = unpacket_traits<PacketType>::size;
+    Index actualRow = IsRowMajor ? row : row + (offset * PacketSize);
+    Index actualCol = IsRowMajor ? col + (offset * PacketSize) : col;
+    eigen_assert(check_array_bounds(actualRow, actualCol, PacketSize) && "Array index out of bounds");
+    return m_argImpl.template packet<LoadMode, PacketType>(actualRow, actualCol);
+  }
+  template <int LoadMode, typename PacketType = SrcPacketType>
+  EIGEN_STRONG_INLINE PacketType srcPacket(Index index, Index offset) const {
+    constexpr int PacketSize = unpacket_traits<PacketType>::size;
+    Index actualIndex = index + (offset * PacketSize);
+    eigen_assert(check_array_bounds(actualIndex, PacketSize) && "Array index out of bounds");
+    return m_argImpl.template packet<LoadMode, PacketType>(actualIndex);
+  }
+
+  // There is no source packet type with equal or fewer elements than DstPacketType.
+  // This is problematic as the evaluation loop may attempt to access data outside the bounds of the array.
+  // For example, consider the cast utilizing pcast<Packet4f,Packet2d> with an array of size 4: {0.0f,1.0f,2.0f,3.0f}. 
+  // The first iteration of the evaulation loop will load 16 bytes: {0.0f,1.0f,2.0f,3.0f} and cast to {0.0,1.0}, which is acceptable.
+  // The second iteration will load 16 bytes: {2.0f,3.0f,?,?}, which is outside the bounds of the array.
+
+  // Instead, perform runtime check to determine if the load would access data outside the bounds of the array.
+  // If not, perform full load. Otherwise, revert to a scalar loop to perform a partial load.
+  // In either case, perform a vectorized cast of the source packet.
+  template <int LoadMode, typename DstPacketType, AltSrcScalarOp<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index row, Index col) const {
+    constexpr int DstPacketSize = unpacket_traits<DstPacketType>::size;
+    constexpr int SrcBytesIncrement = DstPacketSize * sizeof(SrcType);
+    constexpr int SrcLoadMode = plain_enum_min(SrcBytesIncrement, LoadMode);
+    SrcPacketType src;
+    if (EIGEN_PREDICT_TRUE(check_array_bounds(row, col, SrcPacketSize))) {
+      src = srcPacket<SrcLoadMode>(row, col, 0);
+    } else {
+      Array<SrcType, SrcPacketSize, 1> srcArray;
+      for (size_t k = 0; k < DstPacketSize; k++) srcArray[k] = srcCoeff(row, col, k);
+      for (size_t k = DstPacketSize; k < SrcPacketSize; k++) srcArray[k] = SrcType(0);
+      src = pload<SrcPacketType>(srcArray.data());
+    }
+    return pcast<SrcPacketType, DstPacketType>(src);
+  }
+  // Use the source packet type with the same size as DstPacketType, if it exists
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs1<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index row, Index col) const {
+    constexpr int DstPacketSize = unpacket_traits<DstPacketType>::size;
+    using SizedSrcPacketType = typename find_packet_by_size<SrcType, DstPacketSize>::type;
+    constexpr int SrcBytesIncrement = DstPacketSize * sizeof(SrcType);
+    constexpr int SrcLoadMode = plain_enum_min(SrcBytesIncrement, LoadMode);
+    return pcast<SizedSrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode, SizedSrcPacketType>(row, col, 0));
+  }
+  // unpacket_traits<DstPacketType>::size == 2 * SrcPacketSize
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs2<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index row, Index col) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(row, col, 0), srcPacket<SrcLoadMode>(row, col, 1));
+  }
+  // unpacket_traits<DstPacketType>::size == 4 * SrcPacketSize
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs4<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index row, Index col) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(row, col, 0), srcPacket<SrcLoadMode>(row, col, 1),
+        srcPacket<SrcLoadMode>(row, col, 2), srcPacket<SrcLoadMode>(row, col, 3));
+  }
+  // unpacket_traits<DstPacketType>::size == 8 * SrcPacketSize
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs8<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index row, Index col) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(row, col, 0), srcPacket<SrcLoadMode>(row, col, 1), 
+        srcPacket<SrcLoadMode>(row, col, 2), srcPacket<SrcLoadMode>(row, col, 3), 
+        srcPacket<SrcLoadMode>(row, col, 4), srcPacket<SrcLoadMode>(row, col, 5),
+        srcPacket<SrcLoadMode>(row, col, 6), srcPacket<SrcLoadMode>(row, col, 7));
+  }
+
+  // Analagous routines for linear access.
+  template <int LoadMode, typename DstPacketType, AltSrcScalarOp<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index index) const {
+    constexpr int DstPacketSize = unpacket_traits<DstPacketType>::size;
+    constexpr int SrcBytesIncrement = DstPacketSize * sizeof(SrcType);
+    constexpr int SrcLoadMode = plain_enum_min(SrcBytesIncrement, LoadMode);
+    SrcPacketType src;
+    if (EIGEN_PREDICT_TRUE(check_array_bounds(index, SrcPacketSize))) {
+      src = srcPacket<SrcLoadMode>(index, 0);
+    } else {
+      Array<SrcType, SrcPacketSize, 1> srcArray;
+      for (size_t k = 0; k < DstPacketSize; k++) srcArray[k] = srcCoeff(index, k);
+      for (size_t k = DstPacketSize; k < SrcPacketSize; k++) srcArray[k] = SrcType(0);
+      src = pload<SrcPacketType>(srcArray.data());
+    }
+    return pcast<SrcPacketType, DstPacketType>(src);
+  }
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs1<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index index) const {
+    constexpr int DstPacketSize = unpacket_traits<DstPacketType>::size;
+    using SizedSrcPacketType = typename find_packet_by_size<SrcType, DstPacketSize>::type;
+    constexpr int SrcBytesIncrement = DstPacketSize * sizeof(SrcType);
+    constexpr int SrcLoadMode = plain_enum_min(SrcBytesIncrement, LoadMode);
+    return pcast<SizedSrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode, SizedSrcPacketType>(index, 0));
+  }
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs2<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index index) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(index, 0), srcPacket<SrcLoadMode>(index, 1));
+  }
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs4<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index index) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(index, 0), srcPacket<SrcLoadMode>(index, 1),
+        srcPacket<SrcLoadMode>(index, 2), srcPacket<SrcLoadMode>(index, 3));
+  }
+  template <int LoadMode, typename DstPacketType, SrcPacketArgs8<DstPacketType> = true>
+  EIGEN_STRONG_INLINE DstPacketType packet(Index index) const {
+    constexpr int SrcLoadMode = plain_enum_min(SrcPacketBytes, LoadMode);
+    return pcast<SrcPacketType, DstPacketType>(
+        srcPacket<SrcLoadMode>(index, 0), srcPacket<SrcLoadMode>(index, 1),
+        srcPacket<SrcLoadMode>(index, 2), srcPacket<SrcLoadMode>(index, 3),
+        srcPacket<SrcLoadMode>(index, 4), srcPacket<SrcLoadMode>(index, 5),
+        srcPacket<SrcLoadMode>(index, 6), srcPacket<SrcLoadMode>(index, 7));
+  }
+
+  constexpr EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Index rows() const { return m_rows; }
+  constexpr EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Index cols() const { return m_cols; }
+  constexpr EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Index size() const { return m_rows * m_cols; }
+
+ protected:
+  const evaluator<ArgType> m_argImpl;
+  const variable_if_dynamic<Index, XprType::RowsAtCompileTime> m_rows;
+  const variable_if_dynamic<Index, XprType::ColsAtCompileTime> m_cols;
+};
+
 // -------------------- CwiseTernaryOp --------------------
 
 // this is a ternary expression
diff --git a/Eigen/src/Core/GenericPacketMath.h b/Eigen/src/Core/GenericPacketMath.h
index 8cb80bb81..bfc7ae68a 100644
--- a/Eigen/src/Core/GenericPacketMath.h
+++ b/Eigen/src/Core/GenericPacketMath.h
@@ -146,14 +146,67 @@ template<typename T> struct unpacket_traits
 
 template<typename T> struct unpacket_traits<const T> : unpacket_traits<T> { };
 
-template <typename Src, typename Tgt> struct type_casting_traits {
+/** \internal A convenience utility for determining if the type is a scalar.
+ * This is used to enable some generic packet implementations.
+ */
+template <typename Packet>
+struct is_scalar {
+  using Scalar = typename unpacket_traits<Packet>::type;
+  enum { value = internal::is_same<Packet, Scalar>::value };
+};
+
+// automatically and succinctly define combinations of pcast<SrcPacket,TgtPacket> when 
+// 1) the packets are the same type, or
+// 2) the packets differ only in sign. 
+// In both of these cases, preinterpret (bit_cast) is equivalent to pcast (static_cast)
+template <typename SrcPacket, typename TgtPacket,
+          bool Scalar = is_scalar<SrcPacket>::value && is_scalar<TgtPacket>::value>
+struct is_degenerate_helper : is_same<SrcPacket, TgtPacket> {};
+template <>
+struct is_degenerate_helper<int8_t, uint8_t, true> : std::true_type {};
+template <>
+struct is_degenerate_helper<int16_t, uint16_t, true> : std::true_type {};
+template <>
+struct is_degenerate_helper<int32_t, uint32_t, true> : std::true_type {};
+template <>
+struct is_degenerate_helper<int64_t, uint64_t, true> : std::true_type {};
+
+template <typename SrcPacket, typename TgtPacket>
+struct is_degenerate_helper<SrcPacket, TgtPacket, false> {
+  using SrcScalar = typename unpacket_traits<SrcPacket>::type;
+  static constexpr int SrcSize = unpacket_traits<SrcPacket>::size;
+  using TgtScalar = typename unpacket_traits<TgtPacket>::type;
+  static constexpr int TgtSize = unpacket_traits<TgtPacket>::size;
+  static constexpr bool value = is_degenerate_helper<SrcScalar, TgtScalar, true>::value && (SrcSize == TgtSize);
+};
+
+// is_degenerate<T1,T2>::value == is_degenerate<T2,T1>::value
+template <typename SrcPacket, typename TgtPacket>
+struct is_degenerate {
+  static constexpr bool value =
+      is_degenerate_helper<SrcPacket, TgtPacket>::value || is_degenerate_helper<TgtPacket, SrcPacket>::value;
+};
+
+template <typename Packet>
+struct is_half {
+  using Scalar = typename unpacket_traits<Packet>::type;
+  static constexpr int Size = unpacket_traits<Packet>::size;
+  using DefaultPacket = typename packet_traits<Scalar>::type;
+  static constexpr int DefaultSize = unpacket_traits<DefaultPacket>::size;
+  static constexpr bool value = Size < DefaultSize;
+};
+
+template <typename Src, typename Tgt>
+struct type_casting_traits {
   enum {
-    VectorizedCast = 0,
+    VectorizedCast =
+        is_degenerate<Src, Tgt>::value && packet_traits<Src>::Vectorizable && packet_traits<Tgt>::Vectorizable,
     SrcCoeffRatio = 1,
     TgtCoeffRatio = 1
   };
 };
 
+
 /** \internal Wrapper to ensure that multiple packet types can map to the same
     same underlying vector type. */
 template<typename T, int unique_id = 0>
@@ -171,45 +224,84 @@ struct eigen_packet_wrapper
   T m_val;
 };
 
+template <typename Target, typename Packet, bool IsSame = is_same<Target, Packet>::value>
+struct preinterpret_generic;
 
-/** \internal A convenience utility for determining if the type is a scalar.
- * This is used to enable some generic packet implementations.
- */
-template<typename Packet>
-struct is_scalar {
-  using Scalar = typename unpacket_traits<Packet>::type;
-  enum {
-    value = internal::is_same<Packet, Scalar>::value
-  };
+template <typename Target, typename Packet>
+struct preinterpret_generic<Target, Packet, false> {
+  // the packets are not the same, attempt scalar bit_cast
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Target run(const Packet& a) {
+    return numext::bit_cast<Target, Packet>(a);
+  }
 };
 
-/** \internal \returns static_cast<TgtType>(a) (coeff-wise) */
-template <typename SrcPacket, typename TgtPacket>
-EIGEN_DEVICE_FUNC inline TgtPacket
-pcast(const SrcPacket& a) {
-  return static_cast<TgtPacket>(a);
-}
-template <typename SrcPacket, typename TgtPacket>
-EIGEN_DEVICE_FUNC inline TgtPacket
-pcast(const SrcPacket& a, const SrcPacket& /*b*/) {
-  return static_cast<TgtPacket>(a);
-}
-template <typename SrcPacket, typename TgtPacket>
-EIGEN_DEVICE_FUNC inline TgtPacket
-pcast(const SrcPacket& a, const SrcPacket& /*b*/, const SrcPacket& /*c*/, const SrcPacket& /*d*/) {
-  return static_cast<TgtPacket>(a);
-}
-template <typename SrcPacket, typename TgtPacket>
-EIGEN_DEVICE_FUNC inline TgtPacket
-pcast(const SrcPacket& a, const SrcPacket& /*b*/, const SrcPacket& /*c*/, const SrcPacket& /*d*/,
-      const SrcPacket& /*e*/, const SrcPacket& /*f*/, const SrcPacket& /*g*/, const SrcPacket& /*h*/) {
-  return static_cast<TgtPacket>(a);
-}
+template <typename Packet>
+struct preinterpret_generic<Packet, Packet, true> {
+  // the packets are the same type: do nothing
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet run(const Packet& a) { return a; }
+};
 
 /** \internal \returns reinterpret_cast<Target>(a) */
 template <typename Target, typename Packet>
-EIGEN_DEVICE_FUNC inline Target
-preinterpret(const Packet& a); /* { return reinterpret_cast<const Target&>(a); } */
+EIGEN_DEVICE_FUNC inline Target preinterpret(const Packet& a) {
+  return preinterpret_generic<Target, Packet>::run(a);
+}
+
+template <typename SrcPacket, typename TgtPacket, bool Degenerate = is_degenerate<SrcPacket, TgtPacket>::value, bool TgtIsHalf = is_half<TgtPacket>::value>
+struct pcast_generic;
+
+template <typename SrcPacket, typename TgtPacket>
+struct pcast_generic<SrcPacket, TgtPacket, false, false> {
+  // the packets are not degenerate: attempt scalar static_cast
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket run(const SrcPacket& a) {
+    return cast_impl<SrcPacket, TgtPacket>::run(a);
+  }
+};
+
+template <typename Packet>
+struct pcast_generic<Packet, Packet, true, false> {
+  // the packets are the same: do nothing
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Packet run(const Packet& a) { return a; }
+};
+
+template <typename SrcPacket, typename TgtPacket, bool TgtIsHalf>
+struct pcast_generic<SrcPacket, TgtPacket, true, TgtIsHalf> {
+  // the packets are degenerate: preinterpret is equivalent to pcast
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket run(const SrcPacket& a) { return preinterpret<TgtPacket>(a); }
+};
+
+
+
+/** \internal \returns static_cast<TgtType>(a) (coeff-wise) */
+template <typename SrcPacket, typename TgtPacket>
+EIGEN_DEVICE_FUNC inline TgtPacket pcast(const SrcPacket& a) {
+  return pcast_generic<SrcPacket, TgtPacket>::run(a);
+}
+template <typename SrcPacket, typename TgtPacket>
+EIGEN_DEVICE_FUNC inline TgtPacket pcast(const SrcPacket& a, const SrcPacket& b) {
+  return pcast_generic<SrcPacket, TgtPacket>::run(a, b);
+}
+template <typename SrcPacket, typename TgtPacket>
+EIGEN_DEVICE_FUNC inline TgtPacket pcast(const SrcPacket& a, const SrcPacket& b, const SrcPacket& c,
+                                         const SrcPacket& d) {
+  return pcast_generic<SrcPacket, TgtPacket>::run(a, b, c, d);
+}
+template <typename SrcPacket, typename TgtPacket>
+EIGEN_DEVICE_FUNC inline TgtPacket pcast(const SrcPacket& a, const SrcPacket& b, const SrcPacket& c, const SrcPacket& d,
+                                         const SrcPacket& e, const SrcPacket& f, const SrcPacket& g,
+                                         const SrcPacket& h) {
+  return pcast_generic<SrcPacket, TgtPacket>::run(a, b, c, d, e, f, g, h);
+}
+
+template <typename SrcPacket, typename TgtPacket>
+struct pcast_generic<SrcPacket, TgtPacket, false, true> {
+  // TgtPacket is a half packet of some other type
+  // perform cast and truncate result
+  using DefaultTgtPacket = typename is_half<TgtPacket>::DefaultPacket;
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TgtPacket run(const SrcPacket& a) {
+    return preinterpret<TgtPacket>(pcast<SrcPacket, DefaultTgtPacket>(a));
+  }
+};
 
 /** \internal \returns a + b (coeff-wise) */
 template<typename Packet> EIGEN_DEVICE_FUNC inline Packet
diff --git a/Eigen/src/Core/MathFunctions.h b/Eigen/src/Core/MathFunctions.h
index 40ee3f551..d7851e319 100644
--- a/Eigen/src/Core/MathFunctions.h
+++ b/Eigen/src/Core/MathFunctions.h
@@ -430,6 +430,13 @@ struct cast_impl
   }
 };
 
+template <typename OldType>
+struct cast_impl<OldType, bool> {
+  EIGEN_DEVICE_FUNC
+  static inline bool run(const OldType& x) { return x != OldType(0); }
+};
+
+
 // Casting from S -> Complex<T> leads to an implicit conversion from S to T,
 // generating warnings on clang.  Here we explicitly cast the real component.
 template<typename OldType, typename NewType>
diff --git a/Eigen/src/Core/arch/AVX/TypeCasting.h b/Eigen/src/Core/arch/AVX/TypeCasting.h
index 386543e66..461f3a637 100644
--- a/Eigen/src/Core/arch/AVX/TypeCasting.h
+++ b/Eigen/src/Core/arch/AVX/TypeCasting.h
@@ -80,6 +80,14 @@ template<> EIGEN_STRONG_INLINE Packet8i pcast<Packet4d, Packet8i>(const Packet4d
   return _mm256_set_m128i(_mm256_cvttpd_epi32(b), _mm256_cvttpd_epi32(a));
 }
 
+template <> EIGEN_STRONG_INLINE Packet4f pcast<Packet4d, Packet4f>(const Packet4d& a) {
+  return _mm256_cvtpd_ps(a);
+}
+
+template <> EIGEN_STRONG_INLINE Packet4i pcast<Packet4d, Packet4i>(const Packet4d& a) {
+  return _mm256_cvttpd_epi32(a);
+}
+
 template <>
 EIGEN_STRONG_INLINE Packet16b pcast<Packet8f, Packet16b>(const Packet8f& a,
                                                          const Packet8f& b) {
@@ -118,6 +126,44 @@ template<> EIGEN_STRONG_INLINE Packet8f preinterpret<Packet8f,Packet8i>(const Pa
   return _mm256_castsi256_ps(a);
 }
 
+template<> EIGEN_STRONG_INLINE Packet8ui preinterpret<Packet8ui, Packet8i>(const Packet8i& a) {
+  return Packet8ui(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet8i preinterpret<Packet8i, Packet8ui>(const Packet8ui& a) {
+  return Packet8i(a);
+}
+
+// truncation operations
+
+template<> EIGEN_STRONG_INLINE Packet4f preinterpret<Packet4f, Packet8f>(const Packet8f& a) {
+  return _mm256_castps256_ps128(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet2d preinterpret<Packet2d, Packet4d>(const Packet4d& a) {
+  return _mm256_castpd256_pd128(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet4i preinterpret<Packet4i, Packet8i>(const Packet8i& a) {
+  return _mm256_castsi256_si128(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet4ui preinterpret<Packet4ui, Packet8ui>(const Packet8ui& a) {
+  return _mm256_castsi256_si128(a);
+}
+
+
+#ifdef EIGEN_VECTORIZE_AVX2
+template<> EIGEN_STRONG_INLINE Packet4ul preinterpret<Packet4ul, Packet4l>(const Packet4l& a) {
+  return Packet4ul(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet4l preinterpret<Packet4l, Packet4ul>(const Packet4ul& a) {
+  return Packet4l(a);
+}
+
+#endif
+
 template<> EIGEN_STRONG_INLINE Packet8f pcast<Packet8h, Packet8f>(const Packet8h& a) {
   return half2float(a);
 }
diff --git a/Eigen/src/Core/arch/AVX512/TypeCasting.h b/Eigen/src/Core/arch/AVX512/TypeCasting.h
index 02e633552..2f38d7f80 100644
--- a/Eigen/src/Core/arch/AVX512/TypeCasting.h
+++ b/Eigen/src/Core/arch/AVX512/TypeCasting.h
@@ -59,6 +59,13 @@ template<> EIGEN_STRONG_INLINE Packet16i pcast<Packet8d, Packet16i>(const Packet
   return  cat256i(_mm512_cvttpd_epi32(a), _mm512_cvttpd_epi32(b));
 }
 
+template<> EIGEN_STRONG_INLINE Packet8i pcast<Packet8d, Packet8i>(const Packet8d& a) {
+  return _mm512_cvtpd_epi32(a);
+}
+template<> EIGEN_STRONG_INLINE Packet8f pcast<Packet8d, Packet8f>(const Packet8d& a) {
+  return _mm512_cvtpd_ps(a);
+}
+
 template<> EIGEN_STRONG_INLINE Packet16i preinterpret<Packet16i, Packet16f>(const Packet16f& a) {
   return _mm512_castps_si512(a);
 }
@@ -107,12 +114,19 @@ template<> EIGEN_STRONG_INLINE Packet8d preinterpret<Packet8d, Packet2d>(const P
   return _mm512_castpd128_pd512(a);
 }
 
-template<> EIGEN_STRONG_INLINE Packet16f preinterpret<Packet16f, Packet16f>(const Packet16f& a) {
-  return a;
+template<> EIGEN_STRONG_INLINE Packet8i preinterpret<Packet8i, Packet16i>(const Packet16i& a) {
+  return _mm512_castsi512_si256(a);
+}
+template<> EIGEN_STRONG_INLINE Packet4i preinterpret<Packet4i, Packet16i>(const Packet16i& a) {
+  return _mm512_castsi512_si128(a);
 }
 
-template<> EIGEN_STRONG_INLINE Packet8d preinterpret<Packet8d, Packet8d>(const Packet8d& a) {
-  return a;
+template<> EIGEN_STRONG_INLINE Packet8h preinterpret<Packet8h, Packet16h>(const Packet16h& a) {
+  return _mm256_castsi256_si128(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet8bf preinterpret<Packet8bf, Packet16bf>(const Packet16bf& a) {
+  return _mm256_castsi256_si128(a);
 }
 
 #ifndef EIGEN_VECTORIZE_AVX512FP16
@@ -191,6 +205,13 @@ struct type_casting_traits<float, half> {
   };
 };
 
+template<> EIGEN_STRONG_INLINE Packet16h preinterpret<Packet16h, Packet32h>(const Packet32h& a) {
+  return _mm256_castpd_si256(_mm512_extractf64x4_pd(_mm512_castph_pd(a), 0));
+}
+template<> EIGEN_STRONG_INLINE Packet8h preinterpret<Packet8h, Packet32h>(const Packet32h& a) {
+  return _mm256_castsi256_si128(preinterpret<Packet16h>(a));
+}
+
 template <>
 EIGEN_STRONG_INLINE Packet16f pcast<Packet32h, Packet16f>(const Packet32h& a) {
   // Discard second-half of input.
diff --git a/Eigen/src/Core/arch/Default/Half.h b/Eigen/src/Core/arch/Default/Half.h
index c8ca33a5b..17ce13581 100644
--- a/Eigen/src/Core/arch/Default/Half.h
+++ b/Eigen/src/Core/arch/Default/Half.h
@@ -1014,4 +1014,49 @@ struct hash<Eigen::half> {
 } // end namespace std
 #endif
 
+namespace Eigen {
+namespace internal {
+
+template <>
+struct cast_impl<float, half> {
+  EIGEN_DEVICE_FUNC
+  static inline half run(const float& a) {
+#if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
+    (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
+    return __float2half(a);
+#else
+    return half(a);
+#endif
+  }
+};
+
+template <>
+struct cast_impl<int, half> {
+  EIGEN_DEVICE_FUNC
+  static inline half run(const int& a) {
+#if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
+    (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
+    return __float2half(static_cast<float>(a));
+#else
+    return half(static_cast<float>(a));
+#endif
+  }
+};
+
+template <>
+struct cast_impl<half, float> {
+  EIGEN_DEVICE_FUNC
+  static inline float run(const half& a) {
+#if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
+    (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
+    return __half2float(a);
+#else
+    return static_cast<float>(a);
+#endif
+  }
+};
+
+}  // namespace internal
+}  // namespace Eigen
+
 #endif // EIGEN_HALF_H
diff --git a/Eigen/src/Core/arch/Default/TypeCasting.h b/Eigen/src/Core/arch/Default/TypeCasting.h
deleted file mode 100644
index dc779a725..000000000
--- a/Eigen/src/Core/arch/Default/TypeCasting.h
+++ /dev/null
@@ -1,116 +0,0 @@
-// This file is part of Eigen, a lightweight C++ template library
-// for linear algebra.
-//
-// Copyright (C) 2016 Benoit Steiner <benoit.steiner.goog@gmail.com>
-// Copyright (C) 2019 Rasmus Munk Larsen <rmlarsen@google.com>
-//
-// This Source Code Form is subject to the terms of the Mozilla
-// Public License v. 2.0. If a copy of the MPL was not distributed
-// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-#ifndef EIGEN_GENERIC_TYPE_CASTING_H
-#define EIGEN_GENERIC_TYPE_CASTING_H
-
-#include "../../InternalHeaderCheck.h"
-
-namespace Eigen {
-
-namespace internal {
-
-template<>
-struct scalar_cast_op<float, Eigen::half> {
-  typedef Eigen::half result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Eigen::half operator() (const float& a) const {
-    #if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
-      (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
-      return __float2half(a);
-    #else
-      return Eigen::half(a);
-    #endif
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<float, Eigen::half> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-template<>
-struct scalar_cast_op<int, Eigen::half> {
-  typedef Eigen::half result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Eigen::half operator() (const int& a) const {
-    #if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
-      (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
-      return __float2half(static_cast<float>(a));
-    #else
-      return Eigen::half(static_cast<float>(a));
-    #endif
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<int, Eigen::half> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-template<>
-struct scalar_cast_op<Eigen::half, float> {
-  typedef float result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE float operator() (const Eigen::half& a) const {
-    #if (defined(EIGEN_HAS_CUDA_FP16) && defined(EIGEN_CUDA_ARCH) && EIGEN_CUDA_ARCH >= 300) || \
-      (defined(EIGEN_HAS_HIP_FP16) && defined(EIGEN_HIP_DEVICE_COMPILE))
-      return __half2float(a);
-    #else
-      return static_cast<float>(a);
-    #endif
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<Eigen::half, float> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-template<>
-struct scalar_cast_op<float, Eigen::bfloat16> {
-  typedef Eigen::bfloat16 result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Eigen::bfloat16 operator() (const float& a) const {
-    return Eigen::bfloat16(a);
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<float, Eigen::bfloat16> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-template<>
-struct scalar_cast_op<int, Eigen::bfloat16> {
-  typedef Eigen::bfloat16 result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Eigen::bfloat16 operator() (const int& a) const {
-    return Eigen::bfloat16(static_cast<float>(a));
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<int, Eigen::bfloat16> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-template<>
-struct scalar_cast_op<Eigen::bfloat16, float> {
-  typedef float result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE float operator() (const Eigen::bfloat16& a) const {
-    return static_cast<float>(a);
-  }
-};
-
-template<>
-struct functor_traits<scalar_cast_op<Eigen::bfloat16, float> >
-{ enum { Cost = NumTraits<float>::AddCost, PacketAccess = false }; };
-
-
-}
-}
-
-#endif  // EIGEN_GENERIC_TYPE_CASTING_H
diff --git a/Eigen/src/Core/arch/NEON/TypeCasting.h b/Eigen/src/Core/arch/NEON/TypeCasting.h
index add31b917..834fcf53e 100644
--- a/Eigen/src/Core/arch/NEON/TypeCasting.h
+++ b/Eigen/src/Core/arch/NEON/TypeCasting.h
@@ -17,6 +17,61 @@ namespace Eigen {
 
 namespace internal {
 
+
+//==============================================================================
+// preinterpret (truncation operations)
+//==============================================================================
+
+template <>
+EIGEN_STRONG_INLINE Packet8c preinterpret<Packet8c, Packet16c>(const Packet16c& a) {
+  return Packet8c(vget_low_s8(a));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4c preinterpret<Packet4c, Packet8c>(const Packet8c& a) {
+  return Packet4c(vget_lane_s32(vreinterpret_s32_s8(a), 0));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4c preinterpret<Packet4c, Packet16c>(const Packet16c& a) {
+  return preinterpret<Packet4c>(preinterpret<Packet8c>(a));
+}
+
+template <>
+EIGEN_STRONG_INLINE Packet8uc preinterpret<Packet8uc, Packet16uc>(const Packet16uc& a) {
+  return Packet8uc(vget_low_u8(a));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc preinterpret<Packet4uc, Packet8uc>(const Packet8uc& a) {
+  return Packet4uc(vget_lane_u32(vreinterpret_u32_u8(a), 0));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc preinterpret<Packet4uc, Packet16uc>(const Packet16uc& a) {
+  return preinterpret<Packet4uc>(preinterpret<Packet8uc>(a));
+}
+
+template <>
+EIGEN_STRONG_INLINE Packet4s preinterpret<Packet4s, Packet8s>(const Packet8s& a) {
+  return Packet4s(vget_low_s16(a));
+}
+
+template <>
+EIGEN_STRONG_INLINE Packet4us preinterpret<Packet4us, Packet8us>(const Packet8us& a) {
+  return Packet4us(vget_low_u16(a));
+}
+
+template <>
+EIGEN_STRONG_INLINE Packet2i preinterpret<Packet2i, Packet4i>(const Packet4i& a) {
+  return Packet2i(vget_low_s32(a));
+}
+template <>
+EIGEN_STRONG_INLINE Packet2ui preinterpret<Packet2ui, Packet4ui>(const Packet4ui& a) {
+  return Packet2ui(vget_low_u32(a));
+}
+
+template <>
+EIGEN_STRONG_INLINE Packet2f preinterpret<Packet2f, Packet4f>(const Packet4f& a) {
+  return Packet2f(vget_low_f32(a));
+}
+
 //==============================================================================
 // preinterpret
 //==============================================================================
@@ -37,6 +92,7 @@ EIGEN_STRONG_INLINE Packet4f preinterpret<Packet4f, Packet4ui>(const Packet4ui&
   return Packet4f(vreinterpretq_f32_u32(a));
 }
 
+
 template <>
 EIGEN_STRONG_INLINE Packet4c preinterpret<Packet4c, Packet4uc>(const Packet4uc& a) {
   return static_cast<Packet4c>(a);
@@ -50,6 +106,7 @@ EIGEN_STRONG_INLINE Packet16c preinterpret<Packet16c, Packet16uc>(const Packet16
   return Packet16c(vreinterpretq_s8_u8(a));
 }
 
+
 template <>
 EIGEN_STRONG_INLINE Packet4uc preinterpret<Packet4uc, Packet4c>(const Packet4c& a) {
   return static_cast<Packet4uc>(a);
@@ -71,7 +128,6 @@ template <>
 EIGEN_STRONG_INLINE Packet8s preinterpret<Packet8s, Packet8us>(const Packet8us& a) {
   return Packet8s(vreinterpretq_s16_u16(a));
 }
-
 template <>
 EIGEN_STRONG_INLINE Packet4us preinterpret<Packet4us, Packet4s>(const Packet4s& a) {
   return Packet4us(vreinterpret_u16_s16(a));
@@ -127,18 +183,7 @@ EIGEN_STRONG_INLINE Packet2ul preinterpret<Packet2ul, Packet2l>(const Packet2l&
 //==============================================================================
 // pcast, SrcType = float
 //==============================================================================
-template <>
-struct type_casting_traits<float, float> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet4f pcast<Packet4f, Packet4f>(const Packet4f& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet2f pcast<Packet2f, Packet2f>(const Packet2f& a) {
-  return a;
-}
+
 
 template <>
 struct type_casting_traits<float, numext::int64_t> {
@@ -156,10 +201,18 @@ EIGEN_STRONG_INLINE Packet2l pcast<Packet4f, Packet2l>(const Packet4f& a) {
   return vcvtq_s64_f64(vcvt_f64_f32(vget_low_f32(a)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet2l pcast<Packet2f, Packet2l>(const Packet2f& a) {
+  return vcvtq_s64_f64(vcvt_f64_f32(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2ul pcast<Packet4f, Packet2ul>(const Packet4f& a) {
   // Discard second half of input.
   return vcvtq_u64_f64(vcvt_f64_f32(vget_low_f32(a)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ul pcast<Packet2f, Packet2ul>(const Packet2f& a) {
+  return vcvtq_u64_f64(vcvt_f64_f32(a));
+}
 #else
 template <>
 EIGEN_STRONG_INLINE Packet2l pcast<Packet4f, Packet2l>(const Packet4f& a) {
@@ -167,10 +220,19 @@ EIGEN_STRONG_INLINE Packet2l pcast<Packet4f, Packet2l>(const Packet4f& a) {
   return vmovl_s32(vget_low_s32(vcvtq_s32_f32(a)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet2l pcast<Packet2f, Packet2l>(const Packet2f& a) {
+  return vmovl_s32(vcvt_s32_f32(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2ul pcast<Packet4f, Packet2ul>(const Packet4f& a) {
   // Discard second half of input.
   return vmovl_u32(vget_low_u32(vcvtq_u32_f32(a)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ul pcast<Packet2f, Packet2ul>(const Packet2f& a) {
+  // Discard second half of input.
+  return vmovl_u32(vcvt_u32_f32(a));
+}
 #endif  // EIGEN_ARCH_ARM64
 
 template <>
@@ -208,6 +270,10 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet4f, Packet8s>(const Packet4f& a, const
   return vcombine_s16(vmovn_s32(vcvtq_s32_f32(a)), vmovn_s32(vcvtq_s32_f32(b)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet4f, Packet4s>(const Packet4f& a) {
+  return vmovn_s32(vcvtq_s32_f32(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet4s pcast<Packet2f, Packet4s>(const Packet2f& a, const Packet2f& b) {
   return vmovn_s32(vcombine_s32(vcvt_s32_f32(a), vcvt_s32_f32(b)));
 }
@@ -221,6 +287,10 @@ EIGEN_STRONG_INLINE Packet8us pcast<Packet4f, Packet8us>(const Packet4f& a, cons
   return vcombine_u16(vmovn_u32(vcvtq_u32_f32(a)), vmovn_u32(vcvtq_u32_f32(b)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet4f, Packet4us>(const Packet4f& a) {
+  return vmovn_u32(vcvtq_u32_f32(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet4us pcast<Packet2f, Packet4us>(const Packet2f& a, const Packet2f& b) {
   return vmovn_u32(vcombine_u32(vcvt_u32_f32(a), vcvt_u32_f32(b)));
 }
@@ -237,12 +307,25 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet4f, Packet16c>(const Packet4f& a, cons
   return vcombine_s8(vmovn_s16(ab_s16), vmovn_s16(cd_s16));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet4f, Packet8c>(const Packet4f& a, const Packet4f& b) {
+  const int16x8_t ab_s16 = pcast<Packet4f, Packet8s>(a, b);
+  return vmovn_s16(ab_s16);
+}
+template <>
 EIGEN_STRONG_INLINE Packet8c pcast<Packet2f, Packet8c>(const Packet2f& a, const Packet2f& b, const Packet2f& c,
                                                        const Packet2f& d) {
   const int16x4_t ab_s16 = pcast<Packet2f, Packet4s>(a, b);
   const int16x4_t cd_s16 = pcast<Packet2f, Packet4s>(c, d);
   return vmovn_s16(vcombine_s16(ab_s16, cd_s16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet4f, Packet4c>(const Packet4f& a) {
+  const int32x4_t a_s32x4 = vcvtq_s32_f32(a);
+  const int16x4_t a_s16x4 = vmovn_s32(a_s32x4);
+  const int16x8_t aa_s16x8 = vcombine_s16(a_s16x4, a_s16x4);
+  const int8x8_t aa_s8x8 = vmovn_s16(aa_s16x8);
+  return vget_lane_s32(vreinterpret_s32_s8(aa_s8x8), 0);
+}
 
 template <>
 struct type_casting_traits<float, numext::uint8_t> {
@@ -251,16 +334,20 @@ struct type_casting_traits<float, numext::uint8_t> {
 template <>
 EIGEN_STRONG_INLINE Packet16uc pcast<Packet4f, Packet16uc>(const Packet4f& a, const Packet4f& b, const Packet4f& c,
                                                            const Packet4f& d) {
-  const uint16x8_t ab_u16 = pcast<Packet4f, Packet8us>(a, b);
-  const uint16x8_t cd_u16 = pcast<Packet4f, Packet8us>(c, d);
-  return vcombine_u8(vmovn_u16(ab_u16), vmovn_u16(cd_u16));
+  return preinterpret<Packet16uc>(pcast<Packet4f, Packet16c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet4f, Packet8uc>(const Packet4f& a, const Packet4f& b) {
+  return preinterpret<Packet8uc>(pcast<Packet4f, Packet8c>(a, b));
 }
 template <>
 EIGEN_STRONG_INLINE Packet8uc pcast<Packet2f, Packet8uc>(const Packet2f& a, const Packet2f& b, const Packet2f& c,
                                                          const Packet2f& d) {
-  const uint16x4_t ab_u16 = pcast<Packet2f, Packet4us>(a, b);
-  const uint16x4_t cd_u16 = pcast<Packet2f, Packet4us>(c, d);
-  return vmovn_u16(vcombine_u16(ab_u16, cd_u16));
+  return preinterpret<Packet8uc>(pcast<Packet2f, Packet8c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet4f, Packet4uc>(const Packet4f& a) {
+  return static_cast<Packet4uc>(pcast<Packet4f, Packet4c>(a));
 }
 
 //==============================================================================
@@ -276,6 +363,10 @@ EIGEN_STRONG_INLINE Packet4f pcast<Packet16c, Packet4f>(const Packet16c& a) {
   return vcvtq_f32_s32(vmovl_s16(vget_low_s16(vmovl_s8(vget_low_s8(a)))));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4f pcast<Packet4c, Packet4f>(const Packet4c& a) {
+  return vcvtq_f32_s32(vmovl_s16(vget_low_s16(vmovl_s8(vreinterpret_s8_s32(vdup_n_s32(a))))));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet8c, Packet2f>(const Packet8c& a) {
   // Discard all but first 2 bytes.
   return vcvt_f32_s32(vget_low_s32(vmovl_s16(vget_low_s16(vmovl_s8(a)))));
@@ -310,11 +401,20 @@ EIGEN_STRONG_INLINE Packet4i pcast<Packet16c, Packet4i>(const Packet16c& a) {
   return vmovl_s16(vget_low_s16(vmovl_s8(vget_low_s8(a))));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4i pcast<Packet8c, Packet4i>(const Packet8c& a) {
+  return vmovl_s16(vget_low_s16(vmovl_s8(a)));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4i pcast<Packet4c, Packet4i>(const Packet4c& a) {
+  return pcast<Packet8c, Packet4i>(vreinterpret_s8_s32(vdup_n_s32(a)));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2i pcast<Packet8c, Packet2i>(const Packet8c& a) {
   // Discard all but first 2 bytes.
   return vget_low_s32(vmovl_s16(vget_low_s16(vmovl_s8(a))));
 }
 
+
 template <>
 struct type_casting_traits<numext::int8_t, numext::uint32_t> {
   enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 4 };
@@ -327,6 +427,10 @@ template <>
 EIGEN_STRONG_INLINE Packet2ui pcast<Packet8c, Packet2ui>(const Packet8c& a) {
   return preinterpret<Packet2ui>(pcast<Packet8c, Packet2i>(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4ui pcast<Packet4c, Packet4ui>(const Packet4c& a) {
+  return preinterpret<Packet4ui>(pcast<Packet4c, Packet4i>(a));
+}
 
 template <>
 struct type_casting_traits<numext::int8_t, numext::int16_t> {
@@ -338,10 +442,18 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet16c, Packet8s>(const Packet16c& a) {
   return vmovl_s8(vget_low_s8(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8s pcast<Packet8c, Packet8s>(const Packet8c& a) {
+  return vmovl_s8(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet4s pcast<Packet8c, Packet4s>(const Packet8c& a) {
   // Discard second half of input.
   return vget_low_s16(vmovl_s8(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet4c, Packet4s>(const Packet4c& a) {
+  return pcast<Packet8c, Packet4s>(vreinterpret_s8_s32(vdup_n_s32(a)));
+}
 
 template <>
 struct type_casting_traits<numext::int8_t, numext::uint16_t> {
@@ -352,43 +464,18 @@ EIGEN_STRONG_INLINE Packet8us pcast<Packet16c, Packet8us>(const Packet16c& a) {
   return preinterpret<Packet8us>(pcast<Packet16c, Packet8s>(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8us pcast<Packet8c, Packet8us>(const Packet8c& a) {
+  return preinterpret<Packet8us>(pcast<Packet8c, Packet8s>(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet4us pcast<Packet8c, Packet4us>(const Packet8c& a) {
   return preinterpret<Packet4us>(pcast<Packet8c, Packet4s>(a));
 }
-
 template <>
-struct type_casting_traits<numext::int8_t, numext::int8_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet16c pcast<Packet16c, Packet16c>(const Packet16c& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet8c pcast<Packet8c, Packet8c>(const Packet8c& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet4c pcast<Packet4c, Packet4c>(const Packet4c& a) {
-  return a;
+EIGEN_STRONG_INLINE Packet4us pcast<Packet4c, Packet4us>(const Packet4c& a) {
+  return preinterpret<Packet4us>(pcast<Packet4c, Packet4s>(a));
 }
 
-template <>
-struct type_casting_traits<numext::int8_t, numext::uint8_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet16uc pcast<Packet16c, Packet16uc>(const Packet16c& a) {
-  return preinterpret<Packet16uc>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet8uc pcast<Packet8c, Packet8uc>(const Packet8c& a) {
-  return preinterpret<Packet8uc>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet4uc pcast<Packet4c, Packet4uc>(const Packet4c& a) {
-  return static_cast<Packet4uc>(a);
-}
 
 //==============================================================================
 // pcast, SrcType = uint8_t
@@ -403,6 +490,10 @@ EIGEN_STRONG_INLINE Packet4f pcast<Packet16uc, Packet4f>(const Packet16uc& a) {
   return vcvtq_f32_u32(vmovl_u16(vget_low_u16(vmovl_u8(vget_low_u8(a)))));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4f pcast<Packet4uc, Packet4f>(const Packet4uc& a) {
+  return vcvtq_f32_u32(vmovl_u16(vget_low_u16(vmovl_u8(vreinterpret_u8_u32(vdup_n_u32(a))))));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet8uc, Packet2f>(const Packet8uc& a) {
   // Discard all but first 2 bytes.
   return vcvt_f32_u32(vget_low_u32(vmovl_u16(vget_low_u16(vmovl_u8(a)))));
@@ -437,10 +528,18 @@ EIGEN_STRONG_INLINE Packet4ui pcast<Packet16uc, Packet4ui>(const Packet16uc& a)
   return vmovl_u16(vget_low_u16(vmovl_u8(vget_low_u8(a))));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4ui pcast<Packet8uc, Packet4ui>(const Packet8uc& a) {
+  return vmovl_u16(vget_low_u16(vmovl_u8(a)));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2ui pcast<Packet8uc, Packet2ui>(const Packet8uc& a) {
   // Discard all but first 2 bytes.
   return vget_low_u32(vmovl_u16(vget_low_u16(vmovl_u8(a))));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4ui pcast<Packet4uc, Packet4ui>(const Packet4uc& a) {
+  return pcast<Packet8uc, Packet4ui>(vreinterpret_u8_u32(vdup_n_u32(a)));
+}
 
 template <>
 struct type_casting_traits<numext::uint8_t, numext::int32_t> {
@@ -454,6 +553,10 @@ template <>
 EIGEN_STRONG_INLINE Packet2i pcast<Packet8uc, Packet2i>(const Packet8uc& a) {
   return preinterpret<Packet2i>(pcast<Packet8uc, Packet2ui>(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4i pcast<Packet4uc, Packet4i>(const Packet4uc& a) {
+  return preinterpret<Packet4i>(pcast<Packet4uc, Packet4ui>(a));
+}
 
 template <>
 struct type_casting_traits<numext::uint8_t, numext::uint16_t> {
@@ -465,10 +568,14 @@ EIGEN_STRONG_INLINE Packet8us pcast<Packet16uc, Packet8us>(const Packet16uc& a)
   return vmovl_u8(vget_low_u8(a));
 }
 template <>
-EIGEN_STRONG_INLINE Packet4us pcast<Packet8uc, Packet4us>(const Packet8uc& a) {
-  // Discard second half of input.
-  return vget_low_u16(vmovl_u8(a));
+EIGEN_STRONG_INLINE Packet8us pcast<Packet8uc, Packet8us>(const Packet8uc& a) {
+  return vmovl_u8(a);
 }
+template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet4uc, Packet4us>(const Packet4uc& a) {
+  return vget_low_u16(vmovl_u8(vreinterpret_u8_u32(vdup_n_u32(a))));
+}
+
 
 template <>
 struct type_casting_traits<numext::uint8_t, numext::int16_t> {
@@ -479,43 +586,14 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet16uc, Packet8s>(const Packet16uc& a) {
   return preinterpret<Packet8s>(pcast<Packet16uc, Packet8us>(a));
 }
 template <>
-EIGEN_STRONG_INLINE Packet4s pcast<Packet8uc, Packet4s>(const Packet8uc& a) {
-  return preinterpret<Packet4s>(pcast<Packet8uc, Packet4us>(a));
+EIGEN_STRONG_INLINE Packet8s pcast<Packet8uc, Packet8s>(const Packet8uc& a) {
+  return preinterpret<Packet8s>(pcast<Packet8uc, Packet8us>(a));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet4uc, Packet4s>(const Packet4uc& a) {
+  return preinterpret<Packet4s>(pcast<Packet4uc, Packet4us>(a));
 }
 
-template <>
-struct type_casting_traits<numext::uint8_t, numext::uint8_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet16uc pcast<Packet16uc, Packet16uc>(const Packet16uc& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet8uc pcast<Packet8uc, Packet8uc>(const Packet8uc& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet4uc pcast<Packet4uc, Packet4uc>(const Packet4uc& a) {
-  return a;
-}
-
-template <>
-struct type_casting_traits<numext::uint8_t, numext::int8_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet16c pcast<Packet16uc, Packet16c>(const Packet16uc& a) {
-  return preinterpret<Packet16c>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet8c pcast<Packet8uc, Packet8c>(const Packet8uc& a) {
-  return preinterpret<Packet8c>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet4c pcast<Packet4uc, Packet4c>(const Packet4uc& a) {
-  return static_cast<Packet4c>(a);
-}
 
 //==============================================================================
 // pcast, SrcType = int16_t
@@ -530,6 +608,10 @@ EIGEN_STRONG_INLINE Packet4f pcast<Packet8s, Packet4f>(const Packet8s& a) {
   return vcvtq_f32_s32(vmovl_s16(vget_low_s16(a)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4f pcast<Packet4s, Packet4f>(const Packet4s& a) {
+  return vcvtq_f32_s32(vmovl_s16(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet4s, Packet2f>(const Packet4s& a) {
   // Discard second half of input.
   return vcvt_f32_s32(vget_low_s32(vmovl_s16(a)));
@@ -564,6 +646,10 @@ EIGEN_STRONG_INLINE Packet4i pcast<Packet8s, Packet4i>(const Packet8s& a) {
   return vmovl_s16(vget_low_s16(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4i pcast<Packet4s, Packet4i>(const Packet4s& a) {
+  return vmovl_s16(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet2i pcast<Packet4s, Packet2i>(const Packet4s& a) {
   // Discard second half of input.
   return vget_low_s32(vmovl_s16(a));
@@ -578,35 +664,14 @@ EIGEN_STRONG_INLINE Packet4ui pcast<Packet8s, Packet4ui>(const Packet8s& a) {
   return preinterpret<Packet4ui>(pcast<Packet8s, Packet4i>(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4ui pcast<Packet4s, Packet4ui>(const Packet4s& a) {
+  return preinterpret<Packet4ui>(pcast<Packet4s, Packet4i>(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2ui pcast<Packet4s, Packet2ui>(const Packet4s& a) {
   return preinterpret<Packet2ui>(pcast<Packet4s, Packet2i>(a));
 }
 
-template <>
-struct type_casting_traits<numext::int16_t, numext::int16_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet8s pcast<Packet8s, Packet8s>(const Packet8s& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet4s pcast<Packet4s, Packet4s>(const Packet4s& a) {
-  return a;
-}
-
-template <>
-struct type_casting_traits<numext::int16_t, numext::uint16_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet8us pcast<Packet8s, Packet8us>(const Packet8s& a) {
-  return preinterpret<Packet8us>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet4us pcast<Packet4s, Packet4us>(const Packet4s& a) {
-  return preinterpret<Packet4us>(a);
-}
 
 template <>
 struct type_casting_traits<numext::int16_t, numext::int8_t> {
@@ -617,9 +682,18 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet8s, Packet16c>(const Packet8s& a, cons
   return vcombine_s8(vmovn_s16(a), vmovn_s16(b));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet8s, Packet8c>(const Packet8s& a) {
+  return vmovn_s16(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet8c pcast<Packet4s, Packet8c>(const Packet4s& a, const Packet4s& b) {
   return vmovn_s16(vcombine_s16(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet4s, Packet4c>(const Packet4s& a) {
+  const int8x8_t aa_s8x8 = pcast<Packet4s, Packet8c>(a, a);
+  return vget_lane_s32(vreinterpret_s32_s8(aa_s8x8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::int16_t, numext::uint8_t> {
@@ -627,11 +701,19 @@ struct type_casting_traits<numext::int16_t, numext::uint8_t> {
 };
 template <>
 EIGEN_STRONG_INLINE Packet16uc pcast<Packet8s, Packet16uc>(const Packet8s& a, const Packet8s& b) {
-  return vcombine_u8(vmovn_u16(vreinterpretq_u16_s16(a)), vmovn_u16(vreinterpretq_u16_s16(b)));
+  return preinterpret<Packet16uc>(pcast<Packet8s, Packet16c>(a, b));
+}
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet8s, Packet8uc>(const Packet8s& a) {
+  return preinterpret<Packet8uc>(pcast<Packet8s, Packet8c>(a));
 }
 template <>
 EIGEN_STRONG_INLINE Packet8uc pcast<Packet4s, Packet8uc>(const Packet4s& a, const Packet4s& b) {
-  return vmovn_u16(vcombine_u16(vreinterpret_u16_s16(a), vreinterpret_u16_s16(b)));
+  return preinterpret<Packet8uc>(pcast<Packet4s, Packet8c>(a, b));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet4s, Packet4uc>(const Packet4s& a) {
+  return static_cast<Packet4uc>(pcast<Packet4s, Packet4c>(a));
 }
 
 //==============================================================================
@@ -647,6 +729,10 @@ EIGEN_STRONG_INLINE Packet4f pcast<Packet8us, Packet4f>(const Packet8us& a) {
   return vcvtq_f32_u32(vmovl_u16(vget_low_u16(a)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4f pcast<Packet4us, Packet4f>(const Packet4us& a) {
+  return vcvtq_f32_u32(vmovl_u16(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet4us, Packet2f>(const Packet4us& a) {
   // Discard second half of input.
   return vcvt_f32_u32(vget_low_u32(vmovl_u16(a)));
@@ -681,6 +767,10 @@ EIGEN_STRONG_INLINE Packet4ui pcast<Packet8us, Packet4ui>(const Packet8us& a) {
   return vmovl_u16(vget_low_u16(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4ui pcast<Packet4us, Packet4ui>(const Packet4us& a) {
+  return vmovl_u16(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet2ui pcast<Packet4us, Packet2ui>(const Packet4us& a) {
   // Discard second half of input.
   return vget_low_u32(vmovl_u16(a));
@@ -695,35 +785,14 @@ EIGEN_STRONG_INLINE Packet4i pcast<Packet8us, Packet4i>(const Packet8us& a) {
   return preinterpret<Packet4i>(pcast<Packet8us, Packet4ui>(a));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4i pcast<Packet4us, Packet4i>(const Packet4us& a) {
+  return preinterpret<Packet4i>(pcast<Packet4us, Packet4ui>(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet2i pcast<Packet4us, Packet2i>(const Packet4us& a) {
   return preinterpret<Packet2i>(pcast<Packet4us, Packet2ui>(a));
 }
 
-template <>
-struct type_casting_traits<numext::uint16_t, numext::uint16_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet8us pcast<Packet8us, Packet8us>(const Packet8us& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet4us pcast<Packet4us, Packet4us>(const Packet4us& a) {
-  return a;
-}
-
-template <>
-struct type_casting_traits<numext::uint16_t, numext::int16_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet8s pcast<Packet8us, Packet8s>(const Packet8us& a) {
-  return preinterpret<Packet8s>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet4s pcast<Packet4us, Packet4s>(const Packet4us& a) {
-  return preinterpret<Packet4s>(a);
-}
 
 template <>
 struct type_casting_traits<numext::uint16_t, numext::uint8_t> {
@@ -734,9 +803,18 @@ EIGEN_STRONG_INLINE Packet16uc pcast<Packet8us, Packet16uc>(const Packet8us& a,
   return vcombine_u8(vmovn_u16(a), vmovn_u16(b));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet8us, Packet8uc>(const Packet8us& a) {
+  return vmovn_u16(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet8uc pcast<Packet4us, Packet8uc>(const Packet4us& a, const Packet4us& b) {
   return vmovn_u16(vcombine_u16(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet4us, Packet4uc>(const Packet4us& a) {
+  uint8x8_t aa_u8x8 = pcast<Packet4us, Packet8uc>(a, a);
+  return vget_lane_u32(vreinterpret_u32_u8(aa_u8x8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::uint16_t, numext::int8_t> {
@@ -747,9 +825,17 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet8us, Packet16c>(const Packet8us& a, co
   return preinterpret<Packet16c>(pcast<Packet8us, Packet16uc>(a, b));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet8us, Packet8c>(const Packet8us& a) {
+  return preinterpret<Packet8c>(pcast<Packet8us, Packet8uc>(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet8c pcast<Packet4us, Packet8c>(const Packet4us& a, const Packet4us& b) {
   return preinterpret<Packet8c>(pcast<Packet4us, Packet8uc>(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet4us, Packet4c>(const Packet4us& a) {
+  return static_cast<Packet4c>(pcast<Packet4us, Packet4uc>(a));
+}
 
 //==============================================================================
 // pcast, SrcType = int32_t
@@ -776,6 +862,10 @@ EIGEN_STRONG_INLINE Packet2l pcast<Packet4i, Packet2l>(const Packet4i& a) {
   // Discard second half of input.
   return vmovl_s32(vget_low_s32(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2l pcast<Packet2i, Packet2l>(const Packet2i& a) {
+  return vmovl_s32(a);
+}
 
 template <>
 struct type_casting_traits<numext::int32_t, numext::uint64_t> {
@@ -785,32 +875,11 @@ template <>
 EIGEN_STRONG_INLINE Packet2ul pcast<Packet4i, Packet2ul>(const Packet4i& a) {
   return preinterpret<Packet2ul>(pcast<Packet4i, Packet2l>(a));
 }
-
 template <>
-struct type_casting_traits<numext::int32_t, numext::int32_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet4i pcast<Packet4i, Packet4i>(const Packet4i& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet2i pcast<Packet2i, Packet2i>(const Packet2i& a) {
-  return a;
+EIGEN_STRONG_INLINE Packet2ul pcast<Packet2i, Packet2ul>(const Packet2i& a) {
+  return preinterpret<Packet2ul>(pcast<Packet2i, Packet2l>(a));
 }
 
-template <>
-struct type_casting_traits<numext::int32_t, numext::uint32_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet4ui pcast<Packet4i, Packet4ui>(const Packet4i& a) {
-  return preinterpret<Packet4ui>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet2ui pcast<Packet2i, Packet2ui>(const Packet2i& a) {
-  return preinterpret<Packet2ui>(a);
-}
 
 template <>
 struct type_casting_traits<numext::int32_t, numext::int16_t> {
@@ -821,6 +890,10 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet4i, Packet8s>(const Packet4i& a, const
   return vcombine_s16(vmovn_s32(a), vmovn_s32(b));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet4i, Packet4s>(const Packet4i& a) {
+  return vmovn_s32(a);
+}
+template <>
 EIGEN_STRONG_INLINE Packet4s pcast<Packet2i, Packet4s>(const Packet2i& a, const Packet2i& b) {
   return vmovn_s32(vcombine_s32(a, b));
 }
@@ -834,6 +907,10 @@ EIGEN_STRONG_INLINE Packet8us pcast<Packet4i, Packet8us>(const Packet4i& a, cons
   return vcombine_u16(vmovn_u32(vreinterpretq_u32_s32(a)), vmovn_u32(vreinterpretq_u32_s32(b)));
 }
 template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet4i, Packet4us>(const Packet4i& a) {
+  return vmovn_u32(vreinterpretq_u32_s32(a));
+}
+template <>
 EIGEN_STRONG_INLINE Packet4us pcast<Packet2i, Packet4us>(const Packet2i& a, const Packet2i& b) {
   return vmovn_u32(vreinterpretq_u32_s32(vcombine_s32(a, b)));
 }
@@ -850,12 +927,24 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet4i, Packet16c>(const Packet4i& a, cons
   return vcombine_s8(vmovn_s16(ab_s16), vmovn_s16(cd_s16));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet4i, Packet8c>(const Packet4i& a, const Packet4i& b) {
+  const int16x8_t ab_s16 = pcast<Packet4i, Packet8s>(a, b);
+  return vmovn_s16(ab_s16);
+}
+template <>
 EIGEN_STRONG_INLINE Packet8c pcast<Packet2i, Packet8c>(const Packet2i& a, const Packet2i& b, const Packet2i& c,
                                                        const Packet2i& d) {
   const int16x4_t ab_s16 = vmovn_s32(vcombine_s32(a, b));
   const int16x4_t cd_s16 = vmovn_s32(vcombine_s32(c, d));
   return vmovn_s16(vcombine_s16(ab_s16, cd_s16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet4i, Packet4c>(const Packet4i& a) {
+  const int16x4_t a_s16x4 = vmovn_s32(a);
+  const int16x8_t aa_s16x8 = vcombine_s16(a_s16x4, a_s16x4);
+  const int8x8_t aa_s8x8 = vmovn_s16(aa_s16x8);
+  return vget_lane_s32(vreinterpret_s32_s8(aa_s8x8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::int32_t, numext::uint8_t> {
@@ -864,16 +953,20 @@ struct type_casting_traits<numext::int32_t, numext::uint8_t> {
 template <>
 EIGEN_STRONG_INLINE Packet16uc pcast<Packet4i, Packet16uc>(const Packet4i& a, const Packet4i& b, const Packet4i& c,
                                                            const Packet4i& d) {
-  const uint16x8_t ab_u16 = pcast<Packet4i, Packet8us>(a, b);
-  const uint16x8_t cd_u16 = pcast<Packet4i, Packet8us>(c, d);
-  return vcombine_u8(vmovn_u16(ab_u16), vmovn_u16(cd_u16));
+  return preinterpret<Packet16uc>(pcast<Packet4i, Packet16c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet4i, Packet8uc>(const Packet4i& a, const Packet4i& b) {
+  return preinterpret<Packet8uc>(pcast<Packet4i, Packet8c>(a, b));
 }
 template <>
 EIGEN_STRONG_INLINE Packet8uc pcast<Packet2i, Packet8uc>(const Packet2i& a, const Packet2i& b, const Packet2i& c,
                                                          const Packet2i& d) {
-  const uint16x4_t ab_u16 = pcast<Packet2i, Packet4us>(a, b);
-  const uint16x4_t cd_u16 = pcast<Packet2i, Packet4us>(c, d);
-  return vmovn_u16(vcombine_u16(ab_u16, cd_u16));
+  return preinterpret<Packet8uc>(pcast<Packet2i, Packet8c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet4i, Packet4uc>(const Packet4i& a) {
+  return static_cast<Packet4uc>(pcast<Packet4i, Packet4c>(a));
 }
 
 //==============================================================================
@@ -901,6 +994,10 @@ EIGEN_STRONG_INLINE Packet2ul pcast<Packet4ui, Packet2ul>(const Packet4ui& a) {
   // Discard second half of input.
   return vmovl_u32(vget_low_u32(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ul pcast<Packet2ui, Packet2ul>(const Packet2ui& a) {
+  return vmovl_u32(a);
+}
 
 template <>
 struct type_casting_traits<numext::uint32_t, numext::int64_t> {
@@ -910,32 +1007,11 @@ template <>
 EIGEN_STRONG_INLINE Packet2l pcast<Packet4ui, Packet2l>(const Packet4ui& a) {
   return preinterpret<Packet2l>(pcast<Packet4ui, Packet2ul>(a));
 }
-
 template <>
-struct type_casting_traits<numext::uint32_t, numext::uint32_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet4ui pcast<Packet4ui, Packet4ui>(const Packet4ui& a) {
-  return a;
-}
-template <>
-EIGEN_STRONG_INLINE Packet2ui pcast<Packet2ui, Packet2ui>(const Packet2ui& a) {
-  return a;
+EIGEN_STRONG_INLINE Packet2l pcast<Packet2ui, Packet2l>(const Packet2ui& a) {
+  return preinterpret<Packet2l>(pcast<Packet2ui, Packet2ul>(a));
 }
 
-template <>
-struct type_casting_traits<numext::uint32_t, numext::int32_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet4i pcast<Packet4ui, Packet4i>(const Packet4ui& a) {
-  return preinterpret<Packet4i>(a);
-}
-template <>
-EIGEN_STRONG_INLINE Packet2i pcast<Packet2ui, Packet2i>(const Packet2ui& a) {
-  return preinterpret<Packet2i>(a);
-}
 
 template <>
 struct type_casting_traits<numext::uint32_t, numext::uint16_t> {
@@ -949,6 +1025,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4us pcast<Packet2ui, Packet4us>(const Packet2ui& a, const Packet2ui& b) {
   return vmovn_u32(vcombine_u32(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet4ui, Packet4us>(const Packet4ui& a) {
+  return vmovn_u32(a);
+}
 
 template <>
 struct type_casting_traits<numext::uint32_t, numext::int16_t> {
@@ -962,6 +1042,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4s pcast<Packet2ui, Packet4s>(const Packet2ui& a, const Packet2ui& b) {
   return preinterpret<Packet4s>(pcast<Packet2ui, Packet4us>(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet4ui, Packet4s>(const Packet4ui& a) {
+  return preinterpret<Packet4s>(pcast<Packet4ui, Packet4us>(a));
+}
 
 template <>
 struct type_casting_traits<numext::uint32_t, numext::uint8_t> {
@@ -975,12 +1059,24 @@ EIGEN_STRONG_INLINE Packet16uc pcast<Packet4ui, Packet16uc>(const Packet4ui& a,
   return vcombine_u8(vmovn_u16(ab_u16), vmovn_u16(cd_u16));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet4ui, Packet8uc>(const Packet4ui& a, const Packet4ui& b) {
+  const uint16x8_t ab_u16 = vcombine_u16(vmovn_u32(a), vmovn_u32(b));
+  return vmovn_u16(ab_u16);
+}
+template <>
 EIGEN_STRONG_INLINE Packet8uc pcast<Packet2ui, Packet8uc>(const Packet2ui& a, const Packet2ui& b, const Packet2ui& c,
                                                           const Packet2ui& d) {
   const uint16x4_t ab_u16 = vmovn_u32(vcombine_u32(a, b));
   const uint16x4_t cd_u16 = vmovn_u32(vcombine_u32(c, d));
   return vmovn_u16(vcombine_u16(ab_u16, cd_u16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet4ui, Packet4uc>(const Packet4ui& a) {
+  const uint16x4_t a_u16x4 = vmovn_u32(a);
+  const uint16x8_t aa_u16x8 = vcombine_u16(a_u16x4, a_u16x4);
+  const uint8x8_t aa_u8x8 = vmovn_u16(aa_u16x8);
+  return vget_lane_u32(vreinterpret_u32_u8(aa_u8x8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::uint32_t, numext::int8_t> {
@@ -992,10 +1088,18 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet4ui, Packet16c>(const Packet4ui& a, co
   return preinterpret<Packet16c>(pcast<Packet4ui, Packet16uc>(a, b, c, d));
 }
 template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet4ui, Packet8c>(const Packet4ui& a, const Packet4ui& b) {
+  return preinterpret<Packet8c>(pcast<Packet4ui, Packet8uc>(a, b));
+}
+template <>
 EIGEN_STRONG_INLINE Packet8c pcast<Packet2ui, Packet8c>(const Packet2ui& a, const Packet2ui& b, const Packet2ui& c,
                                                         const Packet2ui& d) {
   return preinterpret<Packet8c>(pcast<Packet2ui, Packet8uc>(a, b, c, d));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet4ui, Packet4c>(const Packet4ui& a) {
+  return static_cast<Packet4c>(pcast<Packet4ui, Packet4uc>(a));
+}
 
 //==============================================================================
 // pcast, SrcType = int64_t
@@ -1008,24 +1112,11 @@ template <>
 EIGEN_STRONG_INLINE Packet4f pcast<Packet2l, Packet4f>(const Packet2l& a, const Packet2l& b) {
   return vcvtq_f32_s32(vcombine_s32(vmovn_s64(a), vmovn_s64(b)));
 }
-
 template <>
-struct type_casting_traits<numext::int64_t, numext::int64_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet2l pcast<Packet2l, Packet2l>(const Packet2l& a) {
-  return a;
+EIGEN_STRONG_INLINE Packet2f pcast<Packet2l, Packet2f>(const Packet2l& a) {
+  return vcvt_f32_s32(vmovn_s64(a));
 }
 
-template <>
-struct type_casting_traits<numext::int64_t, numext::uint64_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet2ul pcast<Packet2l, Packet2ul>(const Packet2l& a) {
-  return preinterpret<Packet2ul>(a);
-}
 
 template <>
 struct type_casting_traits<numext::int64_t, numext::int32_t> {
@@ -1035,6 +1126,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4i pcast<Packet2l, Packet4i>(const Packet2l& a, const Packet2l& b) {
   return vcombine_s32(vmovn_s64(a), vmovn_s64(b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2i pcast<Packet2l, Packet2i>(const Packet2l& a) {
+  return vmovn_s64(a);
+}
 
 template <>
 struct type_casting_traits<numext::int64_t, numext::uint32_t> {
@@ -1044,6 +1139,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4ui pcast<Packet2l, Packet4ui>(const Packet2l& a, const Packet2l& b) {
   return vcombine_u32(vmovn_u64(vreinterpretq_u64_s64(a)), vmovn_u64(vreinterpretq_u64_s64(b)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ui pcast<Packet2l, Packet2ui>(const Packet2l& a) {
+  return vmovn_u64(vreinterpretq_u64_s64(a));
+}
 
 template <>
 struct type_casting_traits<numext::int64_t, numext::int16_t> {
@@ -1056,6 +1155,11 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet2l, Packet8s>(const Packet2l& a, const
   const int32x4_t cd_s32 = pcast<Packet2l, Packet4i>(c, d);
   return vcombine_s16(vmovn_s32(ab_s32), vmovn_s32(cd_s32));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet2l, Packet4s>(const Packet2l& a, const Packet2l& b) {
+  const int32x4_t ab_s32 = pcast<Packet2l, Packet4i>(a, b);
+  return vmovn_s32(ab_s32);
+}
 
 template <>
 struct type_casting_traits<numext::int64_t, numext::uint16_t> {
@@ -1064,9 +1168,11 @@ struct type_casting_traits<numext::int64_t, numext::uint16_t> {
 template <>
 EIGEN_STRONG_INLINE Packet8us pcast<Packet2l, Packet8us>(const Packet2l& a, const Packet2l& b, const Packet2l& c,
                                                          const Packet2l& d) {
-  const uint32x4_t ab_u32 = pcast<Packet2l, Packet4ui>(a, b);
-  const uint32x4_t cd_u32 = pcast<Packet2l, Packet4ui>(c, d);
-  return vcombine_u16(vmovn_u32(ab_u32), vmovn_u32(cd_u32));
+  return preinterpret<Packet8us>(pcast<Packet2l, Packet8s>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet2l, Packet4us>(const Packet2l& a, const Packet2l& b) {
+  return preinterpret<Packet4us>(pcast<Packet2l, Packet4s>(a, b));
 }
 
 template <>
@@ -1081,6 +1187,19 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet2l, Packet16c>(const Packet2l& a, cons
   const int16x8_t efgh_s16 = pcast<Packet2l, Packet8s>(e, f, g, h);
   return vcombine_s8(vmovn_s16(abcd_s16), vmovn_s16(efgh_s16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet2l, Packet8c>(const Packet2l& a, const Packet2l& b, const Packet2l& c,
+                                                       const Packet2l& d) {
+  const int16x8_t abcd_s16 = pcast<Packet2l, Packet8s>(a, b, c, d);
+  return vmovn_s16(abcd_s16);
+}
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet2l, Packet4c>(const Packet2l& a, const Packet2l& b) {
+  const int16x4_t ab_s16 = pcast<Packet2l, Packet4s>(a, b);
+  const int16x8_t abab_s16 = vcombine_s16(ab_s16, ab_s16);
+  const int8x8_t abab_s8 = vmovn_s16(abab_s16);
+  return vget_lane_s32(vreinterpret_s32_s8(abab_s8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::int64_t, numext::uint8_t> {
@@ -1094,6 +1213,15 @@ EIGEN_STRONG_INLINE Packet16uc pcast<Packet2l, Packet16uc>(const Packet2l& a, co
   const uint16x8_t efgh_u16 = pcast<Packet2l, Packet8us>(e, f, g, h);
   return vcombine_u8(vmovn_u16(abcd_u16), vmovn_u16(efgh_u16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet2l, Packet8uc>(const Packet2l& a, const Packet2l& b, const Packet2l& c,
+                                                         const Packet2l& d) {
+  return preinterpret<Packet8uc>(pcast<Packet2l, Packet8c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet2l, Packet4uc>(const Packet2l& a, const Packet2l& b) {
+  return static_cast<Packet4uc>(pcast<Packet2l, Packet4c>(a, b));
+}
 
 //==============================================================================
 // pcast, SrcType = uint64_t
@@ -1106,24 +1234,11 @@ template <>
 EIGEN_STRONG_INLINE Packet4f pcast<Packet2ul, Packet4f>(const Packet2ul& a, const Packet2ul& b) {
   return vcvtq_f32_u32(vcombine_u32(vmovn_u64(a), vmovn_u64(b)));
 }
-
 template <>
-struct type_casting_traits<numext::uint64_t, numext::uint64_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet2ul pcast<Packet2ul, Packet2ul>(const Packet2ul& a) {
-  return a;
+EIGEN_STRONG_INLINE Packet2f pcast<Packet2ul, Packet2f>(const Packet2ul& a) {
+  return vcvt_f32_u32(vmovn_u64(a));
 }
 
-template <>
-struct type_casting_traits<numext::uint64_t, numext::int64_t> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet2l pcast<Packet2ul, Packet2l>(const Packet2ul& a) {
-  return preinterpret<Packet2l>(a);
-}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::uint32_t> {
@@ -1133,6 +1248,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4ui pcast<Packet2ul, Packet4ui>(const Packet2ul& a, const Packet2ul& b) {
   return vcombine_u32(vmovn_u64(a), vmovn_u64(b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ui pcast<Packet2ul, Packet2ui>(const Packet2ul& a) {
+  return vmovn_u64(a);
+}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::int32_t> {
@@ -1142,6 +1261,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4i pcast<Packet2ul, Packet4i>(const Packet2ul& a, const Packet2ul& b) {
   return preinterpret<Packet4i>(pcast<Packet2ul, Packet4ui>(a, b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2i pcast<Packet2ul, Packet2i>(const Packet2ul& a) {
+  return preinterpret<Packet2i>(pcast<Packet2ul, Packet2ui>(a));
+}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::uint16_t> {
@@ -1154,6 +1277,10 @@ EIGEN_STRONG_INLINE Packet8us pcast<Packet2ul, Packet8us>(const Packet2ul& a, co
   const uint16x4_t cd_u16 = vmovn_u32(vcombine_u32(vmovn_u64(c), vmovn_u64(d)));
   return vcombine_u16(ab_u16, cd_u16);
 }
+template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet2ul, Packet4us>(const Packet2ul& a, const Packet2ul& b) {
+  return vmovn_u32(vcombine_u32(vmovn_u64(a), vmovn_u64(b)));
+}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::int16_t> {
@@ -1164,6 +1291,10 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet2ul, Packet8s>(const Packet2ul& a, cons
                                                         const Packet2ul& d) {
   return preinterpret<Packet8s>(pcast<Packet2ul, Packet8us>(a, b, c, d));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet2ul, Packet4s>(const Packet2ul& a, const Packet2ul& b) {
+  return preinterpret<Packet4s>(pcast<Packet2ul, Packet4us>(a, b));
+}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::uint8_t> {
@@ -1177,6 +1308,19 @@ EIGEN_STRONG_INLINE Packet16uc pcast<Packet2ul, Packet16uc>(const Packet2ul& a,
   const uint16x8_t efgh_u16 = pcast<Packet2ul, Packet8us>(e, f, g, h);
   return vcombine_u8(vmovn_u16(abcd_u16), vmovn_u16(efgh_u16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet2ul, Packet8uc>(const Packet2ul& a, const Packet2ul& b, const Packet2ul& c,
+                                                          const Packet2ul& d) {
+  const uint16x8_t abcd_u16 = pcast<Packet2ul, Packet8us>(a, b, c, d);
+  return vmovn_u16(abcd_u16);
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet2ul, Packet4uc>(const Packet2ul& a, const Packet2ul& b) {
+  const uint16x4_t ab_u16 = pcast<Packet2ul, Packet4us>(a, b);
+  const uint16x8_t abab_u16 = vcombine_u16(ab_u16, ab_u16);
+  const uint8x8_t abab_u8 = vmovn_u16(abab_u16);
+  return vget_lane_u32(vreinterpret_u32_u8(abab_u8), 0);
+}
 
 template <>
 struct type_casting_traits<numext::uint64_t, numext::int8_t> {
@@ -1188,6 +1332,15 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet2ul, Packet16c>(const Packet2ul& a, co
                                                           const Packet2ul& g, const Packet2ul& h) {
   return preinterpret<Packet16c>(pcast<Packet2ul, Packet16uc>(a, b, c, d, e, f, g, h));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet2ul, Packet8c>(const Packet2ul& a, const Packet2ul& b, const Packet2ul& c,
+                                                        const Packet2ul& d) {
+  return preinterpret<Packet8c>(pcast<Packet2ul, Packet8uc>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet2ul, Packet4c>(const Packet2ul& a, const Packet2ul& b) {
+  return static_cast<Packet4c>(pcast<Packet2ul, Packet4uc>(a, b));
+}
 
 #if EIGEN_ARCH_ARM64
 
@@ -1220,14 +1373,6 @@ EIGEN_STRONG_INLINE Packet4i preinterpret<Packet4i, Packet2d>(const Packet2d& a)
   return Packet4i(vreinterpretq_s32_f64(a));
 }
 
-template <>
-struct type_casting_traits<double, double> {
-  enum { VectorizedCast = 1, SrcCoeffRatio = 1, TgtCoeffRatio = 1 };
-};
-template <>
-EIGEN_STRONG_INLINE Packet2d pcast<Packet2d, Packet2d>(const Packet2d& a) {
-  return a;
-}
 
 template <>
 struct type_casting_traits<double, float> {
@@ -1237,6 +1382,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4f pcast<Packet2d, Packet4f>(const Packet2d& a, const Packet2d& b) {
   return vcombine_f32(vcvt_f32_f64(a), vcvt_f32_f64(b));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2f pcast<Packet2d, Packet2f>(const Packet2d& a) {
+  return vcvt_f32_f64(a);
+}
 
 template <>
 struct type_casting_traits<double, numext::int64_t> {
@@ -1264,6 +1413,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4i pcast<Packet2d, Packet4i>(const Packet2d& a, const Packet2d& b) {
   return vcombine_s32(vmovn_s64(vcvtq_s64_f64(a)), vmovn_s64(vcvtq_s64_f64(b)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2i pcast<Packet2d, Packet2i>(const Packet2d& a) {
+  return vmovn_s64(vcvtq_s64_f64(a));
+}
 
 template <>
 struct type_casting_traits<double, numext::uint32_t> {
@@ -1273,6 +1426,10 @@ template <>
 EIGEN_STRONG_INLINE Packet4ui pcast<Packet2d, Packet4ui>(const Packet2d& a, const Packet2d& b) {
   return vcombine_u32(vmovn_u64(vcvtq_u64_f64(a)), vmovn_u64(vcvtq_u64_f64(b)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2ui pcast<Packet2d, Packet2ui>(const Packet2d& a) {
+  return vmovn_u64(vcvtq_u64_f64(a));
+}
 
 template <>
 struct type_casting_traits<double, numext::int16_t> {
@@ -1285,6 +1442,11 @@ EIGEN_STRONG_INLINE Packet8s pcast<Packet2d, Packet8s>(const Packet2d& a, const
   const int32x4_t cd_s32 = pcast<Packet2d, Packet4i>(c, d);
   return vcombine_s16(vmovn_s32(ab_s32), vmovn_s32(cd_s32));
 }
+template <>
+EIGEN_STRONG_INLINE Packet4s pcast<Packet2d, Packet4s>(const Packet2d& a, const Packet2d& b) {
+  const int32x4_t ab_s32 = pcast<Packet2d, Packet4i>(a, b);
+  return vmovn_s32(ab_s32);
+}
 
 template <>
 struct type_casting_traits<double, numext::uint16_t> {
@@ -1293,9 +1455,11 @@ struct type_casting_traits<double, numext::uint16_t> {
 template <>
 EIGEN_STRONG_INLINE Packet8us pcast<Packet2d, Packet8us>(const Packet2d& a, const Packet2d& b, const Packet2d& c,
                                                          const Packet2d& d) {
-  const uint32x4_t ab_u32 = pcast<Packet2d, Packet4ui>(a, b);
-  const uint32x4_t cd_u32 = pcast<Packet2d, Packet4ui>(c, d);
-  return vcombine_u16(vmovn_u32(ab_u32), vmovn_u32(cd_u32));
+  return preinterpret<Packet8us>(pcast<Packet2d, Packet8s>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4us pcast<Packet2d, Packet4us>(const Packet2d& a, const Packet2d& b) {
+  return preinterpret<Packet4us>(pcast<Packet2d, Packet4s>(a, b));
 }
 
 template <>
@@ -1310,6 +1474,17 @@ EIGEN_STRONG_INLINE Packet16c pcast<Packet2d, Packet16c>(const Packet2d& a, cons
   const int16x8_t efgh_s16 = pcast<Packet2d, Packet8s>(e, f, g, h);
   return vcombine_s8(vmovn_s16(abcd_s16), vmovn_s16(efgh_s16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8c pcast<Packet2d, Packet8c>(const Packet2d& a, const Packet2d& b, const Packet2d& c,
+                                                       const Packet2d& d) {
+  const int16x8_t abcd_s16 = pcast<Packet2d, Packet8s>(a, b, c, d);
+  return vmovn_s16(abcd_s16);
+}
+template <>
+EIGEN_STRONG_INLINE Packet4c pcast<Packet2d, Packet4c>(const Packet2d& a, const Packet2d& b) {
+  const int32x4_t ab_s32 = pcast<Packet2d, Packet4i>(a, b);
+  return pcast<Packet4i, Packet4c>(ab_s32);
+}
 
 template <>
 struct type_casting_traits<double, numext::uint8_t> {
@@ -1323,6 +1498,15 @@ EIGEN_STRONG_INLINE Packet16uc pcast<Packet2d, Packet16uc>(const Packet2d& a, co
   const uint16x8_t efgh_u16 = pcast<Packet2d, Packet8us>(e, f, g, h);
   return vcombine_u8(vmovn_u16(abcd_u16), vmovn_u16(efgh_u16));
 }
+template <>
+EIGEN_STRONG_INLINE Packet8uc pcast<Packet2d, Packet8uc>(const Packet2d& a, const Packet2d& b, const Packet2d& c,
+                                                           const Packet2d& d) {
+  return preinterpret<Packet8uc>(pcast<Packet2d, Packet8c>(a, b, c, d));
+}
+template <>
+EIGEN_STRONG_INLINE Packet4uc pcast<Packet2d, Packet4uc>(const Packet2d& a, const Packet2d& b) {
+  return static_cast<Packet4uc>(pcast<Packet2d, Packet4c>(a, b));
+}
 
 template <>
 struct type_casting_traits<float, double> {
@@ -1333,6 +1517,10 @@ EIGEN_STRONG_INLINE Packet2d pcast<Packet4f, Packet2d>(const Packet4f& a) {
   // Discard second-half of input.
   return vcvt_f64_f32(vget_low_f32(a));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2d pcast<Packet2f, Packet2d>(const Packet2f& a) {
+  return vcvt_f64_f32(a);
+}
 
 template <>
 struct type_casting_traits<numext::int8_t, double> {
@@ -1388,6 +1576,10 @@ EIGEN_STRONG_INLINE Packet2d pcast<Packet4i, Packet2d>(const Packet4i& a) {
   // Discard second half of input.
   return vcvtq_f64_s64(vmovl_s32(vget_low_s32(a)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2d pcast<Packet2i, Packet2d>(const Packet2i& a) {
+  return vcvtq_f64_s64(vmovl_s32(a));
+}
 
 template <>
 struct type_casting_traits<numext::uint32_t, double> {
@@ -1398,6 +1590,10 @@ EIGEN_STRONG_INLINE Packet2d pcast<Packet4ui, Packet2d>(const Packet4ui& a) {
   // Discard second half of input.
   return vcvtq_f64_u64(vmovl_u32(vget_low_u32(a)));
 }
+template <>
+EIGEN_STRONG_INLINE Packet2d pcast<Packet2ui, Packet2d>(const Packet2ui& a) {
+  return vcvtq_f64_u64(vmovl_u32(a));
+}
 
 template <>
 struct type_casting_traits<numext::int64_t, double> {
diff --git a/Eigen/src/Core/arch/SSE/TypeCasting.h b/Eigen/src/Core/arch/SSE/TypeCasting.h
index df5c72c42..0b5aa1c78 100644
--- a/Eigen/src/Core/arch/SSE/TypeCasting.h
+++ b/Eigen/src/Core/arch/SSE/TypeCasting.h
@@ -135,6 +135,13 @@ template<> EIGEN_STRONG_INLINE Packet4i preinterpret<Packet4i,Packet2d>(const Pa
   return _mm_castpd_si128(a);
 }
 
+template<> EIGEN_STRONG_INLINE Packet4ui preinterpret<Packet4ui, Packet4i>(const Packet4i& a) {
+  return Packet4ui(a);
+}
+
+template<> EIGEN_STRONG_INLINE Packet4i preinterpret<Packet4i, Packet4ui>(const Packet4ui& a) {
+  return Packet4i(a);
+}
 // Disable the following code since it's broken on too many platforms / compilers.
 //#elif defined(EIGEN_VECTORIZE_SSE) && (!EIGEN_ARCH_x86_64) && (!EIGEN_COMP_MSVC)
 #if 0
diff --git a/Eigen/src/Core/functors/UnaryFunctors.h b/Eigen/src/Core/functors/UnaryFunctors.h
index 8354c0a76..4760d9b59 100644
--- a/Eigen/src/Core/functors/UnaryFunctors.h
+++ b/Eigen/src/Core/functors/UnaryFunctors.h
@@ -179,16 +179,28 @@ struct scalar_cast_op {
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const NewType operator() (const Scalar& a) const { return cast<Scalar, NewType>(a); }
 };
 
-template <typename Scalar>
-struct scalar_cast_op<Scalar, bool> {
-  typedef bool result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool operator()(const Scalar& a) const { return a != Scalar(0); }
-};
-
 template<typename Scalar, typename NewType>
 struct functor_traits<scalar_cast_op<Scalar,NewType> >
 { enum { Cost = is_same<Scalar, NewType>::value ? 0 : NumTraits<NewType>::AddCost, PacketAccess = false }; };
 
+/** \internal
+ * `core_cast_op` serves to distinguish the vectorized implementation from that of the legacy `scalar_cast_op` for backwards
+ * compatibility. The manner in which packet ops are handled is defined by the specialized unary_evaluator:
+ * `unary_evaluator<CwiseUnaryOp<core_cast_op<SrcType, DstType>, ArgType>, IndexBased>` in CoreEvaluators.h
+ * Otherwise, the non-vectorized behavior is identical to that of `scalar_cast_op`
+ */
+template <typename SrcType, typename DstType>
+struct core_cast_op : scalar_cast_op<SrcType, DstType> {};
+
+template <typename SrcType, typename DstType>
+struct functor_traits<core_cast_op<SrcType, DstType>> {
+  using CastingTraits = type_casting_traits<SrcType, DstType>;
+  enum {
+    Cost = is_same<SrcType, DstType>::value ? 0 : NumTraits<DstType>::AddCost,
+    PacketAccess = CastingTraits::VectorizedCast && (CastingTraits::SrcCoeffRatio <= 8)
+  };
+};
+
 /** \internal
   * \brief Template functor to arithmetically shift a scalar right by a number of bits
   *
diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h
index b5f91bf75..49fa37c0c 100644
--- a/Eigen/src/Core/util/XprHelper.h
+++ b/Eigen/src/Core/util/XprHelper.h
@@ -190,6 +190,30 @@ struct find_best_packet
   typedef typename find_best_packet_helper<Size,typename packet_traits<T>::type>::type type;
 };
 
+template <int Size, typename PacketType,
+          bool Stop = (Size == unpacket_traits<PacketType>::size) ||
+                      is_same<PacketType, typename unpacket_traits<PacketType>::half>::value>
+struct find_packet_by_size_helper;
+template <int Size, typename PacketType>
+struct find_packet_by_size_helper<Size, PacketType, true> {
+  using type = PacketType;
+};
+template <int Size, typename PacketType>
+struct find_packet_by_size_helper<Size, PacketType, false> {
+  using type = typename find_packet_by_size_helper<Size, typename unpacket_traits<PacketType>::half>::type;
+};
+
+template <typename T, int Size>
+struct find_packet_by_size {
+  using type = typename find_packet_by_size_helper<Size, typename packet_traits<T>::type>::type;
+  static constexpr bool value = (Size == unpacket_traits<type>::size);
+};
+template <typename T>
+struct find_packet_by_size<T, 1> {
+  using type = typename unpacket_traits<T>::type;
+  static constexpr bool value = (unpacket_traits<type>::size == 1);
+};
+
 #if EIGEN_MAX_STATIC_ALIGN_BYTES>0
 constexpr inline int compute_default_alignment_helper(int ArrayBytes, int AlignmentBytes) {
   if((ArrayBytes % AlignmentBytes) == 0) {
diff --git a/Eigen/src/plugins/CommonCwiseUnaryOps.h b/Eigen/src/plugins/CommonCwiseUnaryOps.h
index 390759cd0..1c6b28451 100644
--- a/Eigen/src/plugins/CommonCwiseUnaryOps.h
+++ b/Eigen/src/plugins/CommonCwiseUnaryOps.h
@@ -45,7 +45,7 @@ inline const NegativeReturnType
 operator-() const { return NegativeReturnType(derived()); }
 
 
-template<class NewType> struct CastXpr { typedef typename internal::cast_return_type<Derived,const CwiseUnaryOp<internal::scalar_cast_op<Scalar, NewType>, const Derived> >::type Type; };
+template<class NewType> struct CastXpr { typedef typename internal::cast_return_type<Derived,const CwiseUnaryOp<internal::core_cast_op<Scalar, NewType>, const Derived> >::type Type; };
 
 /// \returns an expression of \c *this with the \a Scalar type casted to
 /// \a NewScalar.
diff --git a/test/array_cwise.cpp b/test/array_cwise.cpp
index 989359fe1..1648c7cb4 100644
--- a/test/array_cwise.cpp
+++ b/test/array_cwise.cpp
@@ -9,6 +9,7 @@
 
 #include <vector>
 #include "main.h"
+#include "random_without_cast_overflow.h"
 
 // suppress annoying unsigned integer warnings
 template <typename Scalar, bool IsSigned = NumTraits<Scalar>::IsSigned>
@@ -1213,6 +1214,109 @@ void typed_logicals_test(const ArrayType& m) {
     typed_logicals_test_impl<ArrayType>::run(m);
 }
 
+template <typename SrcType, typename DstType, int RowsAtCompileTime, int ColsAtCompileTime>
+struct cast_test_impl {
+  using SrcArray = Array<SrcType, RowsAtCompileTime, ColsAtCompileTime>;
+  using DstArray = Array<DstType, RowsAtCompileTime, ColsAtCompileTime>;
+  struct RandomOp {
+    inline SrcType operator()(const SrcType&) const {
+      return internal::random_without_cast_overflow<SrcType, DstType>::value();
+    }
+  };
+
+  static constexpr int SrcPacketSize = internal::packet_traits<SrcType>::size;
+  static constexpr int DstPacketSize = internal::packet_traits<DstType>::size;
+  static constexpr int MaxPacketSize = internal::plain_enum_max(SrcPacketSize, DstPacketSize);
+
+  // print non-mangled typenames
+  template <typename T>
+  static std::string printTypeInfo(const T&) {
+    if (internal::is_same<bool, T>::value)
+      return "bool";
+    else if (internal::is_same<int8_t, T>::value)
+      return "int8_t";
+    else if (internal::is_same<int16_t, T>::value)
+      return "int16_t";
+    else if (internal::is_same<int32_t, T>::value)
+      return "int32_t";
+    else if (internal::is_same<int64_t, T>::value)
+      return "int64_t";
+    else if (internal::is_same<uint8_t, T>::value)
+      return "uint8_t";
+    else if (internal::is_same<uint16_t, T>::value)
+      return "uint16_t";
+    else if (internal::is_same<uint32_t, T>::value)
+      return "uint32_t";
+    else if (internal::is_same<uint64_t, T>::value)
+      return "uint64_t";
+    else if (internal::is_same<float, T>::value)
+      return "float";
+    else if (internal::is_same<double, T>::value)
+      return "double";
+    //else if (internal::is_same<long double, T>::value)
+    //  return "long double";
+    else if (internal::is_same<half, T>::value)
+      return "half";
+    else if (internal::is_same<bfloat16, T>::value)
+      return "bfloat16";
+    else
+      return typeid(T).name();
+  }
+
+  static void run() {
+    const Index testRows = RowsAtCompileTime == Dynamic ? ((10 * MaxPacketSize) + 1) : RowsAtCompileTime;
+    const Index testCols = ColsAtCompileTime == Dynamic ? ((10 * MaxPacketSize) + 1) : ColsAtCompileTime;
+    const Index testSize = testRows * testCols;
+    const Index minTestSize = 100;
+    const Index repeats = numext::div_ceil(minTestSize, testSize);
+    SrcArray src(testRows, testCols);
+    DstArray dst(testRows, testCols);
+    for (Index repeat = 0; repeat < repeats; repeat++) {
+      src = src.unaryExpr(RandomOp());
+      dst = src.template cast<DstType>();
+      for (Index i = 0; i < testRows; i++)
+        for (Index j = 0; j < testCols; j++) {
+          DstType ref = internal::cast_impl<SrcType, DstType>::run(src(i, j));
+          bool all_nan = ((numext::isnan)(src(i, j)) && (numext::isnan)(ref) && (numext::isnan)(dst(i, j)));
+          bool is_equal = ref == dst(i, j);
+          bool pass = all_nan || is_equal;
+          if (!pass) {
+            std::cout << printTypeInfo(SrcType()) << ": [" << +src(i, j) << "] to " << printTypeInfo(DstType()) << ": ["
+                      << +dst(i, j) << "] != [" << +ref << "]\n";
+          }
+          VERIFY(pass);
+        }
+    }
+  }
+};
+
+template <int RowsAtCompileTime, int ColsAtCompileTime, typename... ScalarTypes>
+struct cast_tests_impl {
+  using ScalarTuple = std::tuple<ScalarTypes...>;
+  static constexpr size_t ScalarTupleSize = std::tuple_size<ScalarTuple>::value;
+
+  template <size_t i = 0, size_t j = i + 1, bool Done = (i >= ScalarTupleSize - 1) || (j >= ScalarTupleSize)>
+  static std::enable_if_t<Done> run() {}
+
+  template <size_t i = 0, size_t j = i + 1, bool Done = (i >= ScalarTupleSize - 1) || (j >= ScalarTupleSize)>
+  static std::enable_if_t<!Done> run() {
+    using Type1 = typename std::tuple_element<i, ScalarTuple>::type;
+    using Type2 = typename std::tuple_element<j, ScalarTuple>::type;
+    cast_test_impl<Type1, Type2, RowsAtCompileTime, ColsAtCompileTime>::run();
+    cast_test_impl<Type2, Type1, RowsAtCompileTime, ColsAtCompileTime>::run();
+    static constexpr size_t next_i = (j == ScalarTupleSize - 1) ? (i + 1) : (i + 0);
+    static constexpr size_t next_j = (j == ScalarTupleSize - 1) ? (i + 2) : (j + 1);
+    run<next_i, next_j>();
+  }
+};
+
+// for now, remove all references to 'long double' until test passes on all platforms
+template <int RowsAtCompileTime, int ColsAtCompileTime>
+void cast_test() {
+  cast_tests_impl<RowsAtCompileTime, ColsAtCompileTime, bool, int8_t, int16_t, int32_t, int64_t, uint8_t, uint16_t,
+                  uint32_t, uint64_t, float, double, /*long double, */half, bfloat16>::run();
+}
+
 EIGEN_DECLARE_TEST(array_cwise)
 {
   for(int i = 0; i < g_repeat; i++) {
@@ -1269,6 +1373,20 @@ EIGEN_DECLARE_TEST(array_cwise)
     CALL_SUBTEST_3( typed_logicals_test(ArrayX<std::complex<double>>(internal::random<int>(1, EIGEN_TEST_MAX_SIZE))));
   }
 
+  for (int i = 0; i < g_repeat; i++) {
+    CALL_SUBTEST_1((cast_test<1, 1>()));
+    CALL_SUBTEST_2((cast_test<3, 1>()));
+    CALL_SUBTEST_2((cast_test<3, 3>()));
+    CALL_SUBTEST_3((cast_test<5, 1>()));
+    CALL_SUBTEST_3((cast_test<5, 5>()));
+    CALL_SUBTEST_4((cast_test<9, 1>()));
+    CALL_SUBTEST_4((cast_test<9, 9>()));
+    CALL_SUBTEST_5((cast_test<17, 1>()));
+    CALL_SUBTEST_5((cast_test<17, 17>()));
+    CALL_SUBTEST_6((cast_test<Dynamic, 1>()));
+    CALL_SUBTEST_6((cast_test<Dynamic, Dynamic>()));
+  }
+
   VERIFY((internal::is_same< internal::global_math_functions_filtering_base<int>::type, int >::value));
   VERIFY((internal::is_same< internal::global_math_functions_filtering_base<float>::type, float >::value));
   VERIFY((internal::is_same< internal::global_math_functions_filtering_base<Array2i>::type, ArrayBase<Array2i> >::value));