diff --git a/Eigen/src/Core/InnerProduct.h b/Eigen/src/Core/InnerProduct.h
index 686ad1379..ad9844dc9 100644
--- a/Eigen/src/Core/InnerProduct.h
+++ b/Eigen/src/Core/InnerProduct.h
@@ -216,8 +216,8 @@ struct scalar_inner_product_op {
 template <typename Scalar, bool Conj>
 struct scalar_inner_product_op<
     Scalar,
-    typename std::enable_if<internal::is_same<typename ScalarBinaryOpTraits<Scalar, Scalar>::ReturnType, Scalar>::value,
-                            Scalar>::type,
+    std::enable_if_t<internal::is_same<typename ScalarBinaryOpTraits<Scalar, Scalar>::ReturnType, Scalar>::value,
+                     Scalar>,
     Conj> {
   using result_type = Scalar;
   using conj_helper = conditional_conj<Scalar, Conj>;
diff --git a/Eigen/src/Core/NestByValue.h b/Eigen/src/Core/NestByValue.h
index 2ce83a8c5..c2c32c1c7 100644
--- a/Eigen/src/Core/NestByValue.h
+++ b/Eigen/src/Core/NestByValue.h
@@ -52,17 +52,11 @@ class NestByValue : public internal::dense_xpr_base<NestByValue<ExpressionType>
 
   EIGEN_DEVICE_FUNC const ExpressionType& nestedExpression() const { return m_expression; }
 
-  EIGEN_DEVICE_FUNC typename std::enable_if<HasDirectAccess, const Scalar*>::type data() const {
-    return m_expression.data();
-  }
+  EIGEN_DEVICE_FUNC std::enable_if_t<HasDirectAccess, const Scalar*> data() const { return m_expression.data(); }
 
-  EIGEN_DEVICE_FUNC typename std::enable_if<HasDirectAccess, Index>::type innerStride() const {
-    return m_expression.innerStride();
-  }
+  EIGEN_DEVICE_FUNC std::enable_if_t<HasDirectAccess, Index> innerStride() const { return m_expression.innerStride(); }
 
-  EIGEN_DEVICE_FUNC typename std::enable_if<HasDirectAccess, Index>::type outerStride() const {
-    return m_expression.outerStride();
-  }
+  EIGEN_DEVICE_FUNC std::enable_if_t<HasDirectAccess, Index> outerStride() const { return m_expression.outerStride(); }
 
  protected:
   const ExpressionType m_expression;
diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
index febd29542..8a24de330 100644
--- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
+++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
@@ -1072,14 +1072,23 @@ EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
   //    syms x;
   //    cosf = @(x) cos(x);
   //    pade_cosf = pade(cosf(x), x, 0, 'Order', 8)
-  Packet sc1_num = pmadd(ss, pset1<Packet>(80737373), pset1<Packet>(-13853547000));
-  Packet sc2_num = pmadd(sc1_num, ss, pset1<Packet>(727718024880));
-  Packet sc3_num = pmadd(sc2_num, ss, pset1<Packet>(-11275015752000));
-  Packet sc4_num = pmadd(sc3_num, ss, pset1<Packet>(23594700729600));
-  Packet sc1_denum = pmadd(ss, pset1<Packet>(147173), pset1<Packet>(39328920));
-  Packet sc2_denum = pmadd(sc1_denum, ss, pset1<Packet>(5772800880));
-  Packet sc3_denum = pmadd(sc2_denum, ss, pset1<Packet>(522334612800));
-  Packet sc4_denum = pmadd(sc3_denum, ss, pset1<Packet>(23594700729600));
+  const Packet cn4 = pset1<Packet>(80737373);
+  const Packet cn3 = pset1<Packet>(-13853547000);
+  const Packet cn2 = pset1<Packet>(727718024880);
+  const Packet cn1 = pset1<Packet>(-11275015752000);
+  const Packet cn0 = pset1<Packet>(23594700729600);  // shared with cd0
+  const Packet cd3 = pset1<Packet>(147173);
+  const Packet cd2 = pset1<Packet>(39328920);
+  const Packet cd1 = pset1<Packet>(5772800880);
+  const Packet cd0 = pset1<Packet>(522334612800);
+  Packet sc1_num = pmadd(ss, cn4, cn3);
+  Packet sc2_num = pmadd(sc1_num, ss, cn2);
+  Packet sc3_num = pmadd(sc2_num, ss, cn1);
+  Packet sc4_num = pmadd(sc3_num, ss, cn0);
+  Packet sc1_denum = pmadd(ss, cd3, cd2);
+  Packet sc2_denum = pmadd(sc1_denum, ss, cd1);
+  Packet sc3_denum = pmadd(sc2_denum, ss, cd0);
+  Packet sc4_denum = pmadd(sc3_denum, ss, cn0);
   Packet scos = pdiv(sc4_num, sc4_denum);
 
   // Padé approximant of sin(x)
@@ -1090,15 +1099,26 @@ EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
   //    syms x;
   //    sinf = @(x) sin(x);
   //    pade_sinf = pade(sinf(x), x, 0, 'Order', 8, 'OrderMode', 'relative')
-  Packet ss1_num = pmadd(ss, pset1<Packet>(4585922449), pset1<Packet>(-1066023933480));
-  Packet ss2_num = pmadd(ss1_num, ss, pset1<Packet>(83284044283440));
-  Packet ss3_num = pmadd(ss2_num, ss, pset1<Packet>(-2303682236856000));
-  Packet ss4_num = pmadd(ss3_num, ss, pset1<Packet>(15605159573203200));
-  Packet ss1_denum = pmadd(ss, pset1<Packet>(1029037), pset1<Packet>(345207016));
-  Packet ss2_denum = pmadd(ss1_denum, ss, pset1<Packet>(61570292784));
-  Packet ss3_denum = pmadd(ss2_denum, ss, pset1<Packet>(6603948711360));
-  Packet ss4_denum = pmadd(ss3_denum, ss, pset1<Packet>(346781323848960));
-  Packet ssin = pdiv(pmul(s, ss4_num), pmul(pset1<Packet>(45), ss4_denum));
+  const Packet sn4 = pset1<Packet>(4585922449);
+  const Packet sn3 = pset1<Packet>(-1066023933480);
+  const Packet sn2 = pset1<Packet>(83284044283440);
+  const Packet sn1 = pset1<Packet>(-2303682236856000);
+  const Packet sn0 = pset1<Packet>(15605159573203200);
+  const Packet sd3 = pset1<Packet>(1029037);
+  const Packet sd2 = pset1<Packet>(345207016);
+  const Packet sd1 = pset1<Packet>(61570292784);
+  const Packet sd0_inner = pset1<Packet>(6603948711360);
+  const Packet sd0 = pset1<Packet>(346781323848960);
+  const Packet cst_45 = pset1<Packet>(45);
+  Packet ss1_num = pmadd(ss, sn4, sn3);
+  Packet ss2_num = pmadd(ss1_num, ss, sn2);
+  Packet ss3_num = pmadd(ss2_num, ss, sn1);
+  Packet ss4_num = pmadd(ss3_num, ss, sn0);
+  Packet ss1_denum = pmadd(ss, sd3, sd2);
+  Packet ss2_denum = pmadd(ss1_denum, ss, sd1);
+  Packet ss3_denum = pmadd(ss2_denum, ss, sd0_inner);
+  Packet ss4_denum = pmadd(ss3_denum, ss, sd0);
+  Packet ssin = pdiv(pmul(s, ss4_num), pmul(cst_45, ss4_denum));
 
   Packet poly_mask = preinterpret<Packet>(pcmp_eq(pand(q_int, cst_one), pzero(q_int)));
 
diff --git a/Eigen/src/Core/products/GeneralMatrixMatrixTriangular.h b/Eigen/src/Core/products/GeneralMatrixMatrixTriangular.h
index bf2756757..adae3dd6c 100644
--- a/Eigen/src/Core/products/GeneralMatrixMatrixTriangular.h
+++ b/Eigen/src/Core/products/GeneralMatrixMatrixTriangular.h
@@ -87,7 +87,7 @@ struct general_matrix_matrix_triangular_product<Index, LhsScalar, LhsStorageOrde
 
     // !!! mc must be a multiple of nr
     if (mc > Traits::nr) {
-      using UnsignedIndex = typename make_unsigned<Index>::type;
+      using UnsignedIndex = std::make_unsigned_t<Index>;
       mc = (UnsignedIndex(mc) / Traits::nr) * Traits::nr;
     }
 
diff --git a/Eigen/src/Core/products/GeneralMatrixVector.h b/Eigen/src/Core/products/GeneralMatrixVector.h
index b974fb6bd..ff2ce23c8 100644
--- a/Eigen/src/Core/products/GeneralMatrixVector.h
+++ b/Eigen/src/Core/products/GeneralMatrixVector.h
@@ -149,10 +149,8 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
     Index jend = numext::mini(j2 + block_cols, cols);
     Index i = 0;
     for (; i < n8; i += ResPacketSize * 8) {
-      ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0)),
-                c2 = pset1<ResPacket>(ResScalar(0)), c3 = pset1<ResPacket>(ResScalar(0)),
-                c4 = pset1<ResPacket>(ResScalar(0)), c5 = pset1<ResPacket>(ResScalar(0)),
-                c6 = pset1<ResPacket>(ResScalar(0)), c7 = pset1<ResPacket>(ResScalar(0));
+      ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{}), c2 = pzero(ResPacket{}), c3 = pzero(ResPacket{}),
+                c4 = pzero(ResPacket{}), c5 = pzero(ResPacket{}), c6 = pzero(ResPacket{}), c7 = pzero(ResPacket{});
 
       for (Index j = j2; j < jend; j += 1) {
         RhsPacket b0 = pset1<RhsPacket>(rhs(j, 0));
@@ -175,8 +173,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       pstoreu(res + i + ResPacketSize * 7, pmadd(c7, palpha, ploadu<ResPacket>(res + i + ResPacketSize * 7)));
     }
     if (i < n4) {
-      ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0)),
-                c2 = pset1<ResPacket>(ResScalar(0)), c3 = pset1<ResPacket>(ResScalar(0));
+      ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{}), c2 = pzero(ResPacket{}), c3 = pzero(ResPacket{});
 
       for (Index j = j2; j < jend; j += 1) {
         RhsPacket b0 = pset1<RhsPacket>(rhs(j, 0));
@@ -193,8 +190,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       i += ResPacketSize * 4;
     }
     if (i < n3) {
-      ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0)),
-                c2 = pset1<ResPacket>(ResScalar(0));
+      ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{}), c2 = pzero(ResPacket{});
 
       for (Index j = j2; j < jend; j += 1) {
         RhsPacket b0 = pset1<RhsPacket>(rhs(j, 0));
@@ -209,7 +205,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       i += ResPacketSize * 3;
     }
     if (i < n2) {
-      ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0));
+      ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{});
 
       for (Index j = j2; j < jend; j += 1) {
         RhsPacket b0 = pset1<RhsPacket>(rhs(j, 0));
@@ -221,7 +217,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       i += ResPacketSize * 2;
     }
     if (i < n1) {
-      ResPacket c0 = pset1<ResPacket>(ResScalar(0));
+      ResPacket c0 = pzero(ResPacket{});
       for (Index j = j2; j < jend; j += 1) {
         RhsPacket b0 = pset1<RhsPacket>(rhs(j, 0));
         c0 = pcj.pmadd(lhs.template load<LhsPacket, LhsAlignment>(i + 0, j), b0, c0);
@@ -230,7 +226,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       i += ResPacketSize;
     }
     if (HasHalf && i < n_half) {
-      ResPacketHalf c0 = pset1<ResPacketHalf>(ResScalar(0));
+      ResPacketHalf c0 = pzero(ResPacketHalf{});
       for (Index j = j2; j < jend; j += 1) {
         RhsPacketHalf b0 = pset1<RhsPacketHalf>(rhs(j, 0));
         c0 = pcj_half.pmadd(lhs.template load<LhsPacketHalf, LhsAlignment>(i + 0, j), b0, c0);
@@ -240,7 +236,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, ColMajor, ConjugateLh
       i += ResPacketSizeHalf;
     }
     if (HasQuarter && i < n_quarter) {
-      ResPacketQuarter c0 = pset1<ResPacketQuarter>(ResScalar(0));
+      ResPacketQuarter c0 = pzero(ResPacketQuarter{});
       for (Index j = j2; j < jend; j += 1) {
         RhsPacketQuarter b0 = pset1<RhsPacketQuarter>(rhs(j, 0));
         c0 = pcj_quarter.pmadd(lhs.template load<LhsPacketQuarter, LhsAlignment>(i + 0, j), b0, c0);
@@ -328,17 +324,15 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, RowMajor, ConjugateLh
     HasQuarter = (int)ResPacketSizeQuarter < (int)ResPacketSizeHalf
   };
 
-  using UnsignedIndex = typename make_unsigned<Index>::type;
+  using UnsignedIndex = std::make_unsigned_t<Index>;
   const Index fullColBlockEnd = LhsPacketSize * (UnsignedIndex(cols) / LhsPacketSize);
   const Index halfColBlockEnd = LhsPacketSizeHalf * (UnsignedIndex(cols) / LhsPacketSizeHalf);
   const Index quarterColBlockEnd = LhsPacketSizeQuarter * (UnsignedIndex(cols) / LhsPacketSizeQuarter);
 
   Index i = 0;
   for (; i < n8; i += 8) {
-    ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0)),
-              c2 = pset1<ResPacket>(ResScalar(0)), c3 = pset1<ResPacket>(ResScalar(0)),
-              c4 = pset1<ResPacket>(ResScalar(0)), c5 = pset1<ResPacket>(ResScalar(0)),
-              c6 = pset1<ResPacket>(ResScalar(0)), c7 = pset1<ResPacket>(ResScalar(0));
+    ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{}), c2 = pzero(ResPacket{}), c3 = pzero(ResPacket{}),
+              c4 = pzero(ResPacket{}), c5 = pzero(ResPacket{}), c6 = pzero(ResPacket{}), c7 = pzero(ResPacket{});
 
     for (Index j = 0; j < fullColBlockEnd; j += LhsPacketSize) {
       RhsPacket b0 = rhs.template load<RhsPacket, Unaligned>(j, 0);
@@ -383,8 +377,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, RowMajor, ConjugateLh
     res[(i + 7) * resIncr] += alpha * cc7;
   }
   for (; i < n4; i += 4) {
-    ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0)),
-              c2 = pset1<ResPacket>(ResScalar(0)), c3 = pset1<ResPacket>(ResScalar(0));
+    ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{}), c2 = pzero(ResPacket{}), c3 = pzero(ResPacket{});
 
     for (Index j = 0; j < fullColBlockEnd; j += LhsPacketSize) {
       RhsPacket b0 = rhs.template load<RhsPacket, Unaligned>(j, 0);
@@ -413,7 +406,7 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, RowMajor, ConjugateLh
     res[(i + 3) * resIncr] += alpha * cc3;
   }
   for (; i < n2; i += 2) {
-    ResPacket c0 = pset1<ResPacket>(ResScalar(0)), c1 = pset1<ResPacket>(ResScalar(0));
+    ResPacket c0 = pzero(ResPacket{}), c1 = pzero(ResPacket{});
 
     for (Index j = 0; j < fullColBlockEnd; j += LhsPacketSize) {
       RhsPacket b0 = rhs.template load<RhsPacket, Unaligned>(j, 0);
@@ -434,9 +427,9 @@ general_matrix_vector_product<Index, LhsScalar, LhsMapper, RowMajor, ConjugateLh
     res[(i + 1) * resIncr] += alpha * cc1;
   }
   for (; i < rows; ++i) {
-    ResPacket c0 = pset1<ResPacket>(ResScalar(0));
-    ResPacketHalf c0_h = pset1<ResPacketHalf>(ResScalar(0));
-    ResPacketQuarter c0_q = pset1<ResPacketQuarter>(ResScalar(0));
+    ResPacket c0 = pzero(ResPacket{});
+    ResPacketHalf c0_h = pzero(ResPacketHalf{});
+    ResPacketQuarter c0_q = pzero(ResPacketQuarter{});
 
     for (Index j = 0; j < fullColBlockEnd; j += LhsPacketSize) {
       RhsPacket b0 = rhs.template load<RhsPacket, Unaligned>(j, 0);
diff --git a/Eigen/src/Core/util/Meta.h b/Eigen/src/Core/util/Meta.h
index ddbc898e1..4c36d4c1c 100644
--- a/Eigen/src/Core/util/Meta.h
+++ b/Eigen/src/Core/util/Meta.h
@@ -94,13 +94,7 @@ using std::false_type;
 using std::true_type;
 
 template <bool Condition>
-struct bool_constant;
-
-template <>
-struct bool_constant<true> : true_type {};
-
-template <>
-struct bool_constant<false> : false_type {};
+using bool_constant = std::integral_constant<bool, Condition>;
 
 // Third-party libraries rely on these.
 using std::conditional;
@@ -136,77 +130,24 @@ struct remove_all<T*> {
 template <typename T>
 using remove_all_t = typename remove_all<T>::type;
 
+// Eigen's is_arithmetic is similar to std::is_arithmetic but can be specialized
+// for SIMD packet types and other Eigen-specific types. The primary template
+// delegates to std::is_arithmetic for fundamental types.
 template <typename T>
 struct is_arithmetic {
-  enum { value = false };
-};
-template <>
-struct is_arithmetic<float> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<double> {
-  enum { value = true };
+  enum { value = std::is_arithmetic<T>::value };
 };
 // GPU devices treat `long double` as `double`.
-#ifndef EIGEN_GPU_COMPILE_PHASE
+#ifdef EIGEN_GPU_COMPILE_PHASE
 template <>
 struct is_arithmetic<long double> {
-  enum { value = true };
+  enum { value = false };
 };
 #endif
-template <>
-struct is_arithmetic<bool> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<char> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<signed char> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<unsigned char> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<signed short> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<unsigned short> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<signed int> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<unsigned int> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<signed long> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<unsigned long> {
-  enum { value = true };
-};
 
-template <typename T, typename U>
-struct is_same {
-  enum { value = 0 };
-};
-template <typename T>
-struct is_same<T, T> {
-  enum { value = 1 };
-};
+using std::is_same;
 
-template <class T>
-struct is_void : is_same<void, std::remove_const_t<T>> {};
+using std::is_void;
 
 /** \internal
  * Implementation of std::void_t for SFINAE.
@@ -223,26 +164,11 @@ template <typename...>
 using void_t = void;
 #endif
 
-template <>
-struct is_arithmetic<signed long long> {
-  enum { value = true };
-};
-template <>
-struct is_arithmetic<unsigned long long> {
-  enum { value = true };
-};
 using std::is_integral;
 
 using std::make_unsigned;
 
-template <typename T>
-struct is_const {
-  enum { value = 0 };
-};
-template <typename T>
-struct is_const<T const> {
-  enum { value = 1 };
-};
+using std::is_const;
 
 template <typename T>
 struct add_const_on_value_type {
diff --git a/Eigen/src/Core/util/Serializer.h b/Eigen/src/Core/util/Serializer.h
index dc3bd1308..72ce6cb59 100644
--- a/Eigen/src/Core/util/Serializer.h
+++ b/Eigen/src/Core/util/Serializer.h
@@ -129,7 +129,7 @@ struct serialize_impl;
 
 template <size_t N, typename T1, typename... Ts>
 struct serialize_impl<N, T1, Ts...> {
-  using Serializer = Eigen::Serializer<typename std::decay<T1>::type>;
+  using Serializer = Eigen::Serializer<std::decay_t<T1>>;
 
   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE size_t serialize_size(const T1& value, const Ts&... args) {
     Serializer serializer;
diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h
index 378c50179..043b006bc 100644
--- a/Eigen/src/Core/util/XprHelper.h
+++ b/Eigen/src/Core/util/XprHelper.h
@@ -20,11 +20,10 @@ namespace internal {
 
 // useful for unsigned / signed integer comparisons when idx is intended to be non-negative
 template <typename IndexType>
-EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE typename make_unsigned<IndexType>::type returnUnsignedIndexValue(
-    const IndexType& idx) {
+EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::make_unsigned_t<IndexType> returnUnsignedIndexValue(const IndexType& idx) {
   EIGEN_STATIC_ASSERT((NumTraits<IndexType>::IsInteger), THIS FUNCTION IS FOR INTEGER TYPES)
   eigen_internal_assert(idx >= 0 && "Index value is negative and target type is unsigned");
-  using UnsignedType = typename make_unsigned<IndexType>::type;
+  using UnsignedType = std::make_unsigned_t<IndexType>;
   return static_cast<UnsignedType>(idx);
 }