Make nestByValue works again (broken since 3.3) and add unit tests.

Eigen/src/Core/NestByValue.h

@@ -16,7 +16,11 @@ namespace Eigen {
 namespace internal {
 template<typename ExpressionType>
 struct traits<NestByValue<ExpressionType> > : public traits<ExpressionType>
-{};
+{
+  enum {
+    Flags = traits<ExpressionType>::Flags & ~NestByRefBit
+  };
+};
 }
 
 /** \class NestByValue
@@ -43,55 +47,11 @@ template<typename ExpressionType> class NestByValue
 
     EIGEN_DEVICE_FUNC inline Index rows() const { return m_expression.rows(); }
     EIGEN_DEVICE_FUNC inline Index cols() const { return m_expression.cols(); }
-    EIGEN_DEVICE_FUNC inline Index outerStride() const { return m_expression.outerStride(); }
-    EIGEN_DEVICE_FUNC inline Index innerStride() const { return m_expression.innerStride(); }
-
-    EIGEN_DEVICE_FUNC inline const CoeffReturnType coeff(Index row, Index col) const
-    {
-      return m_expression.coeff(row, col);
-    }
-
-    EIGEN_DEVICE_FUNC inline Scalar& coeffRef(Index row, Index col)
-    {
-      return m_expression.const_cast_derived().coeffRef(row, col);
-    }
-
-    EIGEN_DEVICE_FUNC inline const CoeffReturnType coeff(Index index) const
-    {
-      return m_expression.coeff(index);
-    }
-
-    EIGEN_DEVICE_FUNC inline Scalar& coeffRef(Index index)
-    {
-      return m_expression.const_cast_derived().coeffRef(index);
-    }
-
-    template<int LoadMode>
-    EIGEN_DEVICE_FUNC inline const PacketScalar packet(Index row, Index col) const
-    {
-      return m_expression.template packet<LoadMode>(row, col);
-    }
-
-    template<int LoadMode>
-    EIGEN_DEVICE_FUNC inline void writePacket(Index row, Index col, const PacketScalar& x)
-    {
-      m_expression.const_cast_derived().template writePacket<LoadMode>(row, col, x);
-    }
-
-    template<int LoadMode>
-    EIGEN_DEVICE_FUNC inline const PacketScalar packet(Index index) const
-    {
-      return m_expression.template packet<LoadMode>(index);
-    }
-
-    template<int LoadMode>
-    EIGEN_DEVICE_FUNC inline void writePacket(Index index, const PacketScalar& x)
-    {
-      m_expression.const_cast_derived().template writePacket<LoadMode>(index, x);
-    }
 
     EIGEN_DEVICE_FUNC operator const ExpressionType&() const { return m_expression; }
 
+    EIGEN_DEVICE_FUNC const ExpressionType& nestedExpression() const { return m_expression; }
+
   protected:
     const ExpressionType m_expression;
 };
@@ -105,6 +65,21 @@ DenseBase<Derived>::nestByValue() const
   return NestByValue<Derived>(derived());
 }
 
+namespace internal {
+
+// Evaluator of Solve -> eval into a temporary
+template<typename ArgType>
+struct evaluator<NestByValue<ArgType> >
+  : public evaluator<ArgType>
+{
+  typedef evaluator<ArgType> Base;
+
+  EIGEN_DEVICE_FUNC explicit evaluator(const NestByValue<ArgType>& xpr)
+    : Base(xpr.nestedExpression())
+  {}
+};
+}
+
 } // end namespace Eigen
 
 #endif // EIGEN_NESTBYVALUE_H

test/CMakeLists.txt

@@ -268,6 +268,7 @@ ei_add_test(sparselu)
 ei_add_test(sparseqr)
 ei_add_test(umeyama)
 ei_add_test(nesting_ops "${CMAKE_CXX_FLAGS_DEBUG}")
+ei_add_test(nestbyvalue)
 ei_add_test(zerosized)
 ei_add_test(dontalign)
 ei_add_test(evaluators)

test/nestbyvalue.cpp

@@ -0,0 +1,37 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2019 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#define TEST_ENABLE_TEMPORARY_TRACKING
+
+#include "main.h"
+
+typedef NestByValue<MatrixXd> CpyMatrixXd;
+typedef CwiseBinaryOp<internal::scalar_sum_op<double,double>,const CpyMatrixXd,const CpyMatrixXd> XprType;
+
+XprType get_xpr_with_temps(const MatrixXd& a)
+{
+  MatrixXd t1 = a.rowwise().reverse();
+  MatrixXd t2 = a+a;
+  return t1.nestByValue() + t2.nestByValue();
+}
+
+EIGEN_DECLARE_TEST(nestbyvalue)
+{
+  for(int i = 0; i < g_repeat; i++) {
+    Index rows = internal::random<Index>(1,EIGEN_TEST_MAX_SIZE);
+    Index cols = internal::random<Index>(1,EIGEN_TEST_MAX_SIZE);
+    MatrixXd a = MatrixXd(rows,cols);
+    nb_temporaries = 0;
+    XprType x = get_xpr_with_temps(a);
+    VERIFY_IS_EQUAL(nb_temporaries,6);
+    MatrixXd b = x;
+    VERIFY_IS_EQUAL(nb_temporaries,6+1);
+    VERIFY_IS_APPROX(b, a.rowwise().reverse().eval() + (a+a).eval());
+  }
+}