make some changes to please clang, fix some warnings too.

Eigen/Core

@@ -55,6 +55,10 @@
   #define EIGEN_DONT_VECTORIZE
 #endif
 
+#ifdef __clang__
+#define EIGEN_DONT_VECTORIZE
+#endif
+
 #ifndef EIGEN_DONT_VECTORIZE
   #if defined (EIGEN_SSE2_BUT_NOT_OLD_GCC) || defined(EIGEN_SSE2_ON_MSVC_2008_OR_LATER)
     #define EIGEN_VECTORIZE

Eigen/src/Array/VectorwiseOp.h

@@ -381,7 +381,7 @@ template<typename ExpressionType, int Direction> class VectorwiseOp
     const Reverse<ExpressionType, Direction> reverse() const
     { return Reverse<ExpressionType, Direction>( _expression() ); }
 
-    const Replicate<ExpressionType,Direction==Vertical?Dynamic:1,Direction==Horizontal?Dynamic:1>
+    const Replicate<ExpressionType,(Direction==Vertical?Dynamic:1),(Direction==Horizontal?Dynamic:1)>
     replicate(int factor) const;
 
     /** \nonstableyet

Eigen/src/Core/MathFunctions.h

@@ -218,7 +218,7 @@ inline float ei_norm1(const std::complex<float> &x) { return(ei_abs(x.real()) +
 inline std::complex<float> ei_exp(std::complex<float> x)  { return std::exp(x); }
 inline std::complex<float> ei_sin(std::complex<float> x)  { return std::sin(x); }
 inline std::complex<float> ei_cos(std::complex<float> x)  { return std::cos(x); }
-inline std::complex<float> ei_atan2(std::complex<float>, std::complex<float> )  { ei_assert(false); return 0; }
+inline std::complex<float> ei_atan2(std::complex<float>, std::complex<float> )  { ei_assert(false); return 0.f; }
 
 template<> inline std::complex<float> ei_random()
 {
@@ -255,7 +255,7 @@ inline double ei_norm1(const std::complex<double> &x) { return(ei_abs(x.real())
 inline std::complex<double> ei_exp(std::complex<double> x)  { return std::exp(x); }
 inline std::complex<double> ei_sin(std::complex<double> x)  { return std::sin(x); }
 inline std::complex<double> ei_cos(std::complex<double> x)  { return std::cos(x); }
-inline std::complex<double> ei_atan2(std::complex<double>, std::complex<double>)  { ei_assert(false); return 0; }
+inline std::complex<double> ei_atan2(std::complex<double>, std::complex<double>)  { ei_assert(false); return 0.; }
 
 template<> inline std::complex<double> ei_random()
 {

Eigen/src/Core/MatrixStorage.h

@@ -98,7 +98,7 @@ template<typename T, int _Rows, int _Cols, int _Options> class ei_matrix_storage
     inline explicit ei_matrix_storage() {}
     inline ei_matrix_storage(ei_constructor_without_unaligned_array_assert) {}
     inline ei_matrix_storage(int,int,int) {}
-    inline void swap(ei_matrix_storage& other) {}
+    inline void swap(ei_matrix_storage& ) {}
     inline static int rows(void) {return _Rows;}
     inline static int cols(void) {return _Cols;}
     inline void resize(int,int,int) {}

Eigen/src/Core/TriangularMatrix.h

@@ -95,12 +95,14 @@ template<typename Derived> class TriangularBase : public AnyMatrixBase<Derived>
                 || ((Mode==StrictlyLowerTriangular || Mode==UnitLowerTriangular) && col<row));
     }
 
+    #ifdef EIGEN_INTERNAL_DEBUGGING
     void check_coordinates_internal(int row, int col)
     {
-      #ifdef EIGEN_INTERNAL_DEBUGGING
       check_coordinates(row, col);
-      #endif
     }
+    #else
+    void check_coordinates_internal(int , int ) {}
+    #endif
 
 };
 

Eigen/src/Core/products/SelfadjointMatrixMatrix.h

@@ -313,7 +313,6 @@ struct ei_product_selfadjoint_matrix<Scalar,LhsStorageOrder,false,ConjugateLhs,
     int size = cols;
 
     ei_const_blas_data_mapper<Scalar, LhsStorageOrder> lhs(_lhs,lhsStride);
-    ei_const_blas_data_mapper<Scalar, RhsStorageOrder> rhs(_rhs,rhsStride);
 
     if (ConjugateRhs)
       alpha = ei_conj(alpha);

Eigen/src/Core/util/Memory.h

@@ -407,10 +407,10 @@ public:
         ei_aligned_free( p );
     }
 
-    bool operator!=(const aligned_allocator<T>& other) const
+    bool operator!=(const aligned_allocator<T>& ) const
     { return false; }
 
-    bool operator==(const aligned_allocator<T>& other) const
+    bool operator==(const aligned_allocator<T>& ) const
     { return true; }
 };
 

Eigen/src/Core/util/XprHelper.h

@@ -109,7 +109,7 @@ template<int _Rows, int _Cols> struct ei_size_at_compile_time
  * in order to avoid a useless copy
  */
 
-template<typename T, int Sparseness = ei_traits<T>::Flags&SparseBit> class ei_eval;
+template<typename T, int Sparseness = ei_traits<T>::Flags&SparseBit> struct ei_eval;
 
 template<typename T> struct ei_eval<T,IsDense>
 {

Eigen/src/Eigenvalues/Tridiagonalization.h

@@ -197,7 +197,6 @@ void Tridiagonalization<MatrixType>::_compute(MatrixType& matA, CoeffVectorType&
 {
   assert(matA.rows()==matA.cols());
   int n = matA.rows();
-  Matrix<Scalar,1,Dynamic> aux(n);
   for (int i = 0; i<n-1; ++i)
   {
     int remainingSize = n-i-1;