From 5679e439e0c87e4b93ad7870f463d5168edcd57d Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 23 Apr 2018 14:40:16 +0200
Subject: [PATCH] bug #1543: fix linear indexing in generic block evaluation
 (this completes the fix in commit 12efc7d41b80259b996be5781bf596c249c90d3f )

---
 Eigen/src/Core/CoreEvaluators.h | 11 ++++++-----
 test/diagonalmatrices.cpp       |  6 ++++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/Eigen/src/Core/CoreEvaluators.h b/Eigen/src/Core/CoreEvaluators.h
index 8419798c1..6231f2edd 100644
--- a/Eigen/src/Core/CoreEvaluators.h
+++ b/Eigen/src/Core/CoreEvaluators.h
@@ -1087,7 +1087,8 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
   typedef typename XprType::CoeffReturnType CoeffReturnType;
 
   enum {
-    RowsAtCompileTime = XprType::RowsAtCompileTime
+    RowsAtCompileTime = XprType::RowsAtCompileTime,
+    ForwardLinearAccess = InnerPanel && bool(evaluator<ArgType>::Flags&LinearAccessBit)
   };
  
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
@@ -1099,7 +1100,7 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
   CoeffReturnType coeff(Index index) const
   { 
-    if (InnerPanel)
+    if (ForwardLinearAccess)
       return m_argImpl.coeff(m_linear_offset.value() + index); 
     else
       return coeff(RowsAtCompileTime == 1 ? 0 : index, RowsAtCompileTime == 1 ? index : 0);
@@ -1114,7 +1115,7 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
   Scalar& coeffRef(Index index)
   { 
-    if (InnerPanel)
+    if (ForwardLinearAccess)
       return m_argImpl.coeffRef(m_linear_offset.value() + index); 
     else
       return coeffRef(RowsAtCompileTime == 1 ? 0 : index, RowsAtCompileTime == 1 ? index : 0);
@@ -1131,7 +1132,7 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
   EIGEN_STRONG_INLINE
   PacketType packet(Index index) const 
   { 
-    if (InnerPanel)
+    if (ForwardLinearAccess)
       return m_argImpl.template packet<LoadMode,PacketType>(m_linear_offset.value() + index);
     else
       return packet<LoadMode,PacketType>(RowsAtCompileTime == 1 ? 0 : index,
@@ -1149,7 +1150,7 @@ struct unary_evaluator<Block<ArgType, BlockRows, BlockCols, InnerPanel>, IndexBa
   EIGEN_STRONG_INLINE
   void writePacket(Index index, const PacketType& x) 
   {
-    if (InnerPanel)
+    if (ForwardLinearAccess)
       return m_argImpl.template writePacket<StoreMode,PacketType>(m_linear_offset.value() + index, x);
     else
       return writePacket<StoreMode,PacketType>(RowsAtCompileTime == 1 ? 0 : index,
diff --git a/test/diagonalmatrices.cpp b/test/diagonalmatrices.cpp
index cd6dc8cf0..a2092c43e 100644
--- a/test/diagonalmatrices.cpp
+++ b/test/diagonalmatrices.cpp
@@ -99,6 +99,12 @@ template<typename MatrixType> void diagonalmatrices(const MatrixType& m)
   VERIFY_IS_APPROX( (sq_m1 += (s1*v1).asDiagonal()), sq_m2 += (s1*v1).asDiagonal().toDenseMatrix() );
   VERIFY_IS_APPROX( (sq_m1 -= (s1*v1).asDiagonal()), sq_m2 -= (s1*v1).asDiagonal().toDenseMatrix() );
   VERIFY_IS_APPROX( (sq_m1 = (s1*v1).asDiagonal()), (s1*v1).asDiagonal().toDenseMatrix() );
+
+  sq_m1.setRandom();
+  sq_m2 = v1.asDiagonal();
+  sq_m2 = sq_m1 * sq_m2;
+  VERIFY_IS_APPROX( (sq_m1*v1.asDiagonal()).col(i), sq_m2.col(i) );
+  VERIFY_IS_APPROX( (sq_m1*v1.asDiagonal()).row(i), sq_m2.row(i) );
 }
 
 template<int>