diff --git a/Eigen/src/Core/AssignEvaluator.h b/Eigen/src/Core/AssignEvaluator.h
index abaa429ed..66efe8f51 100644
--- a/Eigen/src/Core/AssignEvaluator.h
+++ b/Eigen/src/Core/AssignEvaluator.h
@@ -474,8 +474,8 @@ struct dense_assignment_loop_impl<Kernel, LinearVectorizedTraversal, NoUnrolling
   static constexpr int SrcAlignment = Kernel::AssignmentTraits::JointAlignment;
   static constexpr int DstAlignment = plain_enum_max(Kernel::AssignmentTraits::DstAlignment, alignof(Scalar));
   static constexpr int RequestedAlignment = unpacket_traits<PacketType>::alignment;
-  static constexpr bool Alignable =
-      (DstAlignment >= RequestedAlignment) || ((RequestedAlignment - DstAlignment) % sizeof(Scalar) == 0);
+  static constexpr bool Alignable = (DstAlignment >= RequestedAlignment) ||
+                                    (static_cast<std::size_t>(RequestedAlignment - DstAlignment) % sizeof(Scalar) == 0);
   static constexpr int Alignment = Alignable ? RequestedAlignment : DstAlignment;
   static constexpr bool DstIsAligned = DstAlignment >= Alignment;
   static constexpr bool UsePacketSegment = Kernel::AssignmentTraits::UsePacketSegment;
@@ -587,8 +587,8 @@ struct dense_assignment_loop_impl<Kernel, SliceVectorizedTraversal, NoUnrolling>
   static constexpr int SrcAlignment = Kernel::AssignmentTraits::JointAlignment;
   static constexpr int DstAlignment = plain_enum_max(Kernel::AssignmentTraits::DstAlignment, alignof(Scalar));
   static constexpr int RequestedAlignment = unpacket_traits<PacketType>::alignment;
-  static constexpr bool Alignable =
-      (DstAlignment >= RequestedAlignment) || ((RequestedAlignment - DstAlignment) % sizeof(Scalar) == 0);
+  static constexpr bool Alignable = (DstAlignment >= RequestedAlignment) ||
+                                    (static_cast<std::size_t>(RequestedAlignment - DstAlignment) % sizeof(Scalar) == 0);
   static constexpr int Alignment = Alignable ? RequestedAlignment : DstAlignment;
   static constexpr bool DstIsAligned = DstAlignment >= Alignment;
   static constexpr bool UsePacketSegment = Kernel::AssignmentTraits::UsePacketSegment;
diff --git a/Eigen/src/Core/Visitor.h b/Eigen/src/Core/Visitor.h
index fa6293fea..079429cef 100644
--- a/Eigen/src/Core/Visitor.h
+++ b/Eigen/src/Core/Visitor.h
@@ -46,6 +46,7 @@ struct visitor_impl<Visitor, Derived, UnrollCount, Vectorize, false, ShortCircui
 
   static constexpr bool CanVectorize(int K) {
     constexpr int InnerSizeAtCompileTime = RowMajor ? ColsAtCompileTime : RowsAtCompileTime;
+    if (InnerSizeAtCompileTime <= 0) return false;
     if (InnerSizeAtCompileTime < PacketSize) return false;
     return Vectorize && (InnerSizeAtCompileTime - (K % InnerSizeAtCompileTime) >= PacketSize);
   }
diff --git a/Eigen/src/Core/arch/AVX/PacketMath.h b/Eigen/src/Core/arch/AVX/PacketMath.h
index df94f70be..d28a53b49 100644
--- a/Eigen/src/Core/arch/AVX/PacketMath.h
+++ b/Eigen/src/Core/arch/AVX/PacketMath.h
@@ -2127,7 +2127,7 @@ EIGEN_STRONG_INLINE Packet8h ptrue(const Packet8h& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet8h pabs(const Packet8h& a) {
-  const __m128i sign_mask = _mm_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  const __m128i sign_mask = _mm_set1_epi16(static_cast<short>(0x8000u));
   return _mm_andnot_si128(sign_mask, a);
 }
 
@@ -2282,7 +2282,7 @@ EIGEN_STRONG_INLINE Packet8h pconj(const Packet8h& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet8h pnegate(const Packet8h& a) {
-  Packet8h sign_mask = _mm_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  Packet8h sign_mask = _mm_set1_epi16(static_cast<short>(0x8000u));
   return _mm_xor_si128(a, sign_mask);
 }
 
@@ -2561,7 +2561,7 @@ EIGEN_STRONG_INLINE Packet8bf ptrue(const Packet8bf& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet8bf pabs(const Packet8bf& a) {
-  const __m128i sign_mask = _mm_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  const __m128i sign_mask = _mm_set1_epi16(static_cast<short>(0x8000u));
   return _mm_andnot_si128(sign_mask, a);
 }
 
@@ -2654,7 +2654,7 @@ EIGEN_STRONG_INLINE Packet8bf pconj(const Packet8bf& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet8bf pnegate(const Packet8bf& a) {
-  Packet8bf sign_mask = _mm_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  Packet8bf sign_mask = _mm_set1_epi16(static_cast<short>(0x8000u));
   return _mm_xor_si128(a, sign_mask);
 }
 
diff --git a/Eigen/src/Core/arch/AVX512/PacketMath.h b/Eigen/src/Core/arch/AVX512/PacketMath.h
index 22271e1a8..0c271e116 100644
--- a/Eigen/src/Core/arch/AVX512/PacketMath.h
+++ b/Eigen/src/Core/arch/AVX512/PacketMath.h
@@ -2178,7 +2178,7 @@ EIGEN_STRONG_INLINE Packet16h ptrue(const Packet16h& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet16h pabs(const Packet16h& a) {
-  const __m256i sign_mask = _mm256_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  const __m256i sign_mask = _mm256_set1_epi16(static_cast<short>(0x8000u));
   return _mm256_andnot_si256(sign_mask, a);
 }
 
@@ -2275,7 +2275,7 @@ EIGEN_STRONG_INLINE Packet16h pconj(const Packet16h& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet16h pnegate(const Packet16h& a) {
-  Packet16h sign_mask = _mm256_set1_epi16(static_cast<unsigned short>(0x8000));
+  Packet16h sign_mask = _mm256_set1_epi16(static_cast<short>(0x8000u));
   return _mm256_xor_si256(a, sign_mask);
 }
 
@@ -2766,7 +2766,7 @@ EIGEN_STRONG_INLINE Packet16bf pcmp_lt_or_nan(const Packet16bf& a, const Packet1
 
 template <>
 EIGEN_STRONG_INLINE Packet16bf pnegate(const Packet16bf& a) {
-  Packet16bf sign_mask = _mm256_set1_epi16(static_cast<unsigned short>(0x8000));
+  Packet16bf sign_mask = _mm256_set1_epi16(static_cast<short>(0x8000u));
   return _mm256_xor_si256(a, sign_mask);
 }
 
@@ -2777,7 +2777,7 @@ EIGEN_STRONG_INLINE Packet16bf pconj(const Packet16bf& a) {
 
 template <>
 EIGEN_STRONG_INLINE Packet16bf pabs(const Packet16bf& a) {
-  const __m256i sign_mask = _mm256_set1_epi16(static_cast<numext::uint16_t>(0x8000));
+  const __m256i sign_mask = _mm256_set1_epi16(static_cast<short>(0x8000u));
   return _mm256_andnot_si256(sign_mask, a);
 }
 
diff --git a/Eigen/src/Core/arch/AVX512/PacketMathFP16.h b/Eigen/src/Core/arch/AVX512/PacketMathFP16.h
index 370fb8336..551a94a5c 100644
--- a/Eigen/src/Core/arch/AVX512/PacketMathFP16.h
+++ b/Eigen/src/Core/arch/AVX512/PacketMathFP16.h
@@ -878,19 +878,17 @@ EIGEN_STRONG_INLINE Packet8h pnmsub(const Packet8h& a, const Packet8h& b, const
 
 template <>
 EIGEN_STRONG_INLINE Packet32h pnegate<Packet32h>(const Packet32h& a) {
-  return _mm512_castsi512_ph(
-      _mm512_xor_si512(_mm512_castph_si512(a), _mm512_set1_epi16(static_cast<std::uint16_t>(0x8000u))));
+  return _mm512_castsi512_ph(_mm512_xor_si512(_mm512_castph_si512(a), _mm512_set1_epi16(static_cast<short>(0x8000u))));
 }
 
 template <>
 EIGEN_STRONG_INLINE Packet16h pnegate<Packet16h>(const Packet16h& a) {
-  return _mm256_castsi256_ph(
-      _mm256_xor_si256(_mm256_castph_si256(a), _mm256_set1_epi16(static_cast<std::uint16_t>(0x8000u))));
+  return _mm256_castsi256_ph(_mm256_xor_si256(_mm256_castph_si256(a), _mm256_set1_epi16(static_cast<short>(0x8000u))));
 }
 
 template <>
 EIGEN_STRONG_INLINE Packet8h pnegate<Packet8h>(const Packet8h& a) {
-  return _mm_castsi128_ph(_mm_xor_si128(_mm_castph_si128(a), _mm_set1_epi16(static_cast<std::uint16_t>(0x8000u))));
+  return _mm_castsi128_ph(_mm_xor_si128(_mm_castph_si128(a), _mm_set1_epi16(static_cast<short>(0x8000u))));
 }
 
 // pconj
diff --git a/Eigen/src/Core/util/Memory.h b/Eigen/src/Core/util/Memory.h
index 64bceb3d1..fe34b0b23 100644
--- a/Eigen/src/Core/util/Memory.h
+++ b/Eigen/src/Core/util/Memory.h
@@ -420,7 +420,7 @@ template <typename T>
 EIGEN_DEVICE_FUNC inline T* aligned_new(std::size_t size) {
   check_size_for_overflow<T>(size);
   T* result = static_cast<T*>(aligned_malloc(sizeof(T) * size));
-  EIGEN_TRY { return default_construct_elements_of_array(result, size); }
+  EIGEN_TRY { default_construct_elements_of_array(result, size); }
   EIGEN_CATCH(...) {
     aligned_free(result);
     EIGEN_THROW;
@@ -432,7 +432,7 @@ template <typename T, bool Align>
 EIGEN_DEVICE_FUNC inline T* conditional_aligned_new(std::size_t size) {
   check_size_for_overflow<T>(size);
   T* result = static_cast<T*>(conditional_aligned_malloc<Align>(sizeof(T) * size));
-  EIGEN_TRY { return default_construct_elements_of_array(result, size); }
+  EIGEN_TRY { default_construct_elements_of_array(result, size); }
   EIGEN_CATCH(...) {
     conditional_aligned_free<Align>(result);
     EIGEN_THROW;
diff --git a/test/mixingtypes.cpp b/test/mixingtypes.cpp
index 78032b5fc..1deae95da 100644
--- a/test/mixingtypes.cpp
+++ b/test/mixingtypes.cpp
@@ -293,7 +293,8 @@ void mixingtypes(int size = SizeAtCompileType) {
 }
 
 EIGEN_DECLARE_TEST(mixingtypes) {
-  g_called = false;  // Silence -Wunneeded-internal-declaration.
+  g_called = false;  // Silence -Wunneeded-internal-declaration and set_but_not_used.
+  VERIFY(true || g_called);
   for (int i = 0; i < g_repeat; i++) {
     CALL_SUBTEST_1(mixingtypes<3>());
     CALL_SUBTEST_2(mixingtypes<4>());
diff --git a/test/packetmath.cpp b/test/packetmath.cpp
index 6620096d7..38c27d709 100644
--- a/test/packetmath.cpp
+++ b/test/packetmath.cpp
@@ -298,7 +298,7 @@ struct test_cast_helper<SrcPacket, TgtPacket, SrcCoeffRatio, TgtCoeffRatio, true
     }
 
     for (int i = 0; i < DataSize; ++i) {
-      ref[i] = static_cast<const TgtScalar>(data1[i]);
+      ref[i] = static_cast<TgtScalar>(data1[i]);
     }
 
     pcast_array<SrcPacket, TgtPacket, SrcCoeffRatio, TgtCoeffRatio>::cast(data1, DataSize, data2);