fix two perf issues in product.

fix positive definite test in Cholesky.
remove #include <cstring> in CoreDeclaration.

Eigen/CoreDeclarations

@@ -30,7 +30,6 @@
 
 #include <cstdlib>
 #include <cmath>
-#include <cstring>
 #include <complex>
 #include <cassert>
 #include <functional>

Eigen/src/Cholesky/Cholesky.h

@@ -96,7 +96,7 @@ void Cholesky<MatrixType>::compute(const MatrixType& a)
 
   RealScalar x;
   x = ei_real(a.coeff(0,0));
-  m_isPositiveDefinite = x > precision<Scalar>() && ei_isMuchSmallerThan(ei_imag(m_matrix.coeff(0,0)), RealScalar(1));
+  m_isPositiveDefinite = x > precision<Scalar>() && ei_isMuchSmallerThan(ei_imag(a.coeff(0,0)), RealScalar(1));
   m_matrix.coeffRef(0,0) = ei_sqrt(x);
   m_matrix.col(0).end(size-1) = a.row(0).end(size-1).adjoint() / ei_real(m_matrix.coeff(0,0));
   for (int j = 1; j < size; ++j)
@@ -105,7 +105,7 @@ void Cholesky<MatrixType>::compute(const MatrixType& a)
     x = ei_real(tmp);
     if (x < precision<Scalar>() || (!ei_isMuchSmallerThan(ei_imag(tmp), RealScalar(1))))
     {
-      m_isPositiveDefinite = m_isPositiveDefinite;
+      m_isPositiveDefinite = false;
       return;
     }
     m_matrix.coeffRef(j,j) = x = ei_sqrt(x);
@@ -117,6 +117,7 @@ void Cholesky<MatrixType>::compute(const MatrixType& a)
       m_matrix.col(j).end(endSize) =
         (m_matrix.block(j+1, 0, endSize, j) * m_matrix.row(j).start(j).adjoint()).lazy();
 
+      // FIXME could use a.col instead of a.row
       m_matrix.col(j).end(endSize) = (a.row(j).end(endSize).adjoint()
         - m_matrix.col(j).end(endSize) ) / x;
     }

Eigen/src/Core/CacheFriendlyProduct.h

@@ -402,8 +402,9 @@ EIGEN_DONT_INLINE static void ei_cache_friendly_product_colmajor_times_vector(
   {
     ei_internal_assert(size_t(lhs+lhsAlignmentOffset)%sizeof(Packet)==0 || size<PacketSize);
     
-    for (; skipColumns<PacketSize && alignedStart != lhsAlignmentOffset + alignmentStep*skipColumns; ++skipColumns)
+    while (skipColumns<PacketSize &&
-    {}
+           alignedStart != ((lhsAlignmentOffset + alignmentStep*skipColumns)%PacketSize))
+      ++skipColumns;
     if (skipColumns==PacketSize)
     {
       // nothing can be aligned, no need to skip any column
@@ -568,7 +569,7 @@ EIGEN_DONT_INLINE static void ei_cache_friendly_product_rowmajor_times_vector(
   typedef typename ei_packet_traits<Scalar>::type Packet;
   const int PacketSize = sizeof(Packet)/sizeof(Scalar);
 
-  enum { AllAligned, EvenAligned, FirstAligned, NoneAligned };
+  enum { AllAligned=0, EvenAligned=1, FirstAligned=2, NoneAligned=3 };
   const int rowsAtOnce = 4;
   const int peels = 2;
   const int PacketAlignedMask = PacketSize-1;
@@ -595,8 +596,9 @@ EIGEN_DONT_INLINE static void ei_cache_friendly_product_rowmajor_times_vector(
   {
     ei_internal_assert(size_t(lhs+lhsAlignmentOffset)%sizeof(Packet)==0  || size<PacketSize);
     
-    for (; skipRows<PacketSize && alignedStart != lhsAlignmentOffset + alignmentStep*skipRows; ++skipRows)
+    while (skipRows<PacketSize &&
-    {}
+           alignedStart != ((lhsAlignmentOffset + alignmentStep*skipRows)%PacketSize))
+      ++skipRows;
     if (skipRows==PacketSize)
     {
       // nothing can be aligned, no need to skip any column
@@ -611,7 +613,7 @@ EIGEN_DONT_INLINE static void ei_cache_friendly_product_rowmajor_times_vector(
     ei_internal_assert((alignmentPattern==NoneAligned) || PacketSize==1
       || (size_t(lhs+alignedStart+lhsStride*skipRows)%sizeof(Packet))==0);
   }
-
+  
   int rowBound = ((res.size()-skipRows)/rowsAtOnce)*rowsAtOnce + skipRows;
   for (int i=skipRows; i<rowBound; i+=rowsAtOnce)
   {

Eigen/src/Core/Product.h

@@ -637,7 +637,7 @@ struct ei_cache_friendly_product_selector<ProductType,1,LhsOrder,LhsAccess,RhsCo
   typedef typename ei_traits<ProductType>::_LhsNested Lhs;
   enum {
       UseLhsDirectly = ((ei_packet_traits<Scalar>::size==1) || (Lhs::Flags&ActualPacketAccessBit))
-                     && (!(Lhs::Flags & RowMajorBit)) };
+                     && (Lhs::Flags & RowMajorBit) };
 
   template<typename DestDerived>
   inline static void run(DestDerived& res, const ProductType& product)

Eigen/src/QR/HessenbergDecomposition.h

@@ -49,8 +49,9 @@ template<typename _MatrixType> class HessenbergDecomposition
     enum {
       Size = MatrixType::RowsAtCompileTime,
       SizeMinusOne = MatrixType::RowsAtCompileTime==Dynamic
-                        ? Dynamic
+                   ? Dynamic
-                        : MatrixType::RowsAtCompileTime-1};
+                   : MatrixType::RowsAtCompileTime-1
+    };
 
     typedef Matrix<Scalar, SizeMinusOne, 1> CoeffVectorType;
     typedef Matrix<RealScalar, Size, 1> DiagonalType;
@@ -59,8 +60,7 @@ template<typename _MatrixType> class HessenbergDecomposition
     typedef typename NestByValue<DiagonalCoeffs<MatrixType> >::RealReturnType DiagonalReturnType;
 
     typedef typename NestByValue<DiagonalCoeffs<
-        NestByValue<Block<
+        NestByValue<Block<MatrixType,SizeMinusOne,SizeMinusOne> > > >::RealReturnType SubDiagonalReturnType;
-          MatrixType,SizeMinusOne,SizeMinusOne> > > >::RealReturnType SubDiagonalReturnType;
 
     /** This constructor initializes a HessenbergDecomposition object for
       * further use with HessenbergDecomposition::compute()
@@ -171,11 +171,11 @@ void HessenbergDecomposition<MatrixType>::_compute(MatrixType& matA, CoeffVector
 
       // first let's do A = H A
       matA.corner(BottomRight,n-i-1,n-i-1) -= ((ei_conj(h) * matA.col(i).end(n-i-1)) *
-        (matA.col(i).end(n-i-1).adjoint() * matA.corner(BottomRight,n-i-1,n-i-1)).lazy()).lazy();
+        (matA.col(i).end(n-i-1).adjoint() * matA.corner(BottomRight,n-i-1,n-i-1))).lazy();
 
       // now let's do A = A H
-      matA.corner(BottomRight,n,n-i-1) -= ((matA.corner(BottomRight,n,n-i-1) * matA.col(i).end(n-i-1)).lazy() *
+      matA.corner(BottomRight,n,n-i-1) -= ((matA.corner(BottomRight,n,n-i-1) * matA.col(i).end(n-i-1))
-        (h * matA.col(i).end(n-i-1).adjoint())).lazy();
+                                        * (h * matA.col(i).end(n-i-1).adjoint())).lazy();
 
       matA.col(i).coeffRef(i+1) = beta;
       hCoeffs.coeffRef(i) = h;