Merge.

2 files changed, 9 insertions, 10 deletions

diff --git a/Eigen/src/Core/arch/SSE/MathFunctions.h b/Eigen/src/Core/arch/SSE/MathFunctions.h
index 3c0020248..99662eb6d 100644
--- a/Eigen/src/Core/arch/SSE/MathFunctions.h
+++ b/Eigen/src/Core/arch/SSE/MathFunctions.h
@@ -369,10 +369,14 @@ static EIGEN_DONT_INLINE EIGEN_UNUSED Packet4f ei_pcos(Packet4f x)
 // For detail see here: http://www.beyond3d.com/content/articles/8/
 static EIGEN_UNUSED Packet4f ei_psqrt(Packet4f _x)
 {
-  Packet4f half = ei_pmul(_x, ei_pset1(.5f));
-  Packet4f x = _mm_rsqrt_ps(_x);
-  x = ei_pmul(x, ei_psub(ei_pset1(1.5f), ei_pmul(half, ei_pmul(x,x))));
-  return ei_pmul(_x,x);
+	Packet4f half = ei_pmul(_x, ei_pset1(.5f));
+	
+	/* select only the inverse sqrt of non-zero inputs */
+	Packet4f non_zero_mask = _mm_cmpgt_ps(_x, ei_pset1(std::numeric_limits<float>::epsilon()));
+	Packet4f x = _mm_and_ps(non_zero_mask, _mm_rsqrt_ps(_x));
+
+	x = ei_pmul(x, ei_psub(ei_pset1(1.5f), ei_pmul(half, ei_pmul(x,x))));
+	return ei_pmul(_x,x);
 }
 
 #endif // EIGEN_MATH_FUNCTIONS_SSE_H
diff --git a/Eigen/src/Eigenvalues/RealSchur.h b/Eigen/src/Eigenvalues/RealSchur.h
index eb400c815..395b80089 100644
--- a/Eigen/src/Eigenvalues/RealSchur.h
+++ b/Eigen/src/Eigenvalues/RealSchur.h
@@ -131,17 +131,12 @@ void RealSchur<MatrixType>::hqr2()
   Scalar exshift = 0.0;
   Scalar p=0,q=0,r=0,s=0,z=0,w,x,y;
 
-  // Store roots isolated by balanc and compute matrix norm
+  // Compute matrix norm
   // FIXME to be efficient the following would requires a triangular reduxion code
   // Scalar norm = m_matT.upper().cwiseAbs().sum() + m_matT.corner(BottomLeft,n,n).diagonal().cwiseAbs().sum();
   Scalar norm = 0.0;
   for (int j = 0; j < size; ++j)
   {
-    // FIXME what's the purpose of the following since the condition is always false
-    if ((j < low) || (j > high))
-    {
-      m_eivalues.coeffRef(j) = ComplexScalar(m_matT.coeff(j,j), 0.0);
-    }
     norm += m_matT.row(j).segment(std::max(j-1,0), size-std::max(j-1,0)).cwiseAbs().sum();
   }