gcc11 compile error

[yangbai90]

When compiling with gcc11.2.0, the following error occurs:

In file included from /home/by/Projects/GitHub/AsFem/external/eigen/Eigen/Core:330,
                 from /home/by/Projects/GitHub/AsFem/external/eigen/Eigen/Dense:1,
                 from /home/by/Projects/GitHub/AsFem/external/eigen/Eigen/Eigen:1,
                 from /home/by/Projects/GitHub/AsFem/src/Utils/MathUtils/RankTwoTensor.cpp:17:
/home/by/Projects/GitHub/AsFem/external/eigen/Eigen/src/Core/products/TriangularMatrixVector.h: In static member function ‘static void Eigen::internal::trmv_selector<Mode, 1>::run(const Lhs&, const Rhs&, Dest&, const typename Dest::Scalar&) [with Lhs = Eigen::Transpose<const Eigen::Block<const Eigen::Block<Eigen::Matrix<double, 3, 3>, -1, -1, false>, -1, -1, false> >; Rhs = Eigen::Transpose<const Eigen::CwiseBinaryOp<Eigen::internal::scalar_product_op<double, double>, const Eigen::CwiseNullaryOp<Eigen::internal::scalar_constant_op<double>, const Eigen::Matrix<double, 1, -1, 1, 1, 3> >, const Eigen::Transpose<const Eigen::Block<const Eigen::Block<const Eigen::Block<Eigen::Matrix<double, 3, 3>, -1, -1, false>, -1, 1, true>, -1, 1, false> > > >; Dest = Eigen::Transpose<Eigen::Block<Eigen::Block<Eigen::Matrix<double, -1, -1, 1, -1, -1>, 1, -1, true>, 1, -1, false> >; int Mode = 6]’:
/home/by/Projects/GitHub/AsFem/external/eigen/Eigen/src/Core/products/TriangularMatrixVector.h:332:12: error: ‘result’ may be used uninitialized [-Werror=maybe-uninitialized]
  327 |     internal::triangular_matrix_vector_product
      |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  328 |       <Index,Mode,
      |       ~~~~~~~~~~~~
  329 |        LhsScalar, LhsBlasTraits::NeedToConjugate,
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  330 |        RhsScalar, RhsBlasTraits::NeedToConjugate,
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  331 |        RowMajor>
      |        ~~~~~~~~~
  332 |       ::run(actualLhs.rows(),actualLhs.cols(),
      |       ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  333 |             actualLhs.data(),actualLhs.outerStride(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  334 |             actualRhsPtr,1,
      |             ~~~~~~~~~~~~~~~
  335 |             dest.data(),dest.innerStride(),
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  336 |             actualAlpha);
      |             ~~~~~~~~~~~~
/home/by/Projects/GitHub/AsFem/external/eigen/Eigen/src/Core/products/TriangularMatrixVector.h:105:24: note: by argument 5 of type ‘const double*’ to ‘static void Eigen::internal::triangular_matrix_vector_product<Index, Mode, LhsScalar, ConjLhs, RhsScalar, ConjRhs, 1, Version>::run(Index, Index, const LhsScalar*, Index, const RhsScalar*, Index, Eigen::internal::triangular_matrix_vector_product<Index, Mode, LhsScalar, ConjLhs, RhsScalar, ConjRhs, 1, Version>::ResScalar*, Index, const ResScalar&) [with Index = long int; int Mode = 6; LhsScalar = double; bool ConjLhs = false; RhsScalar = double; bool ConjRhs = false; int Version = 0]’ declared here
  105 | EIGEN_DONT_INLINE void triangular_matrix_vector_product<Index,Mode,LhsScalar,ConjLhs,RhsScalar,ConjRhs,RowMajor,Version>
      |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[ 14%] Building CXX object CMakeFiles/asfem.dir/src/InputSystem/PostprocessBlockReader.cpp.o

[yangbai90]

This issue is reported here: https://gitlab.com/libeigen/eigen/-/issues/2304

[yangbai90]

This issue can be resolved by adding *reinterpret_cast<unsigned char*>(actualRhsPtr) = 0 after actualRhsPtr. Otherwise, one should use -DCMAKE_BUILD_TYPE=Release.