Fix misused of std::move which prevented copy elision of temporaries

Fixed thanks to g++-9.1

src/algebra/TinyMatrix.hpp

@@ -45,14 +45,20 @@ class TinyMatrix
     for (size_t i = 0; i < N * N; ++i) {
       opposed.m_values[i] = -m_values[i];
     }
-    return std::move(opposed);
+    return opposed;
   }
 
   PUGS_INLINE
   constexpr friend TinyMatrix operator*(const T& t, const TinyMatrix& A)
   {
     TinyMatrix B = A;
-    return std::move(B *= t);
+    return B *= t;
+  }
+
+  PUGS_INLINE
+  constexpr friend TinyMatrix operator*(const T& t, TinyMatrix&& A)
+  {
+    return std::move(A *= t);
   }
 
   PUGS_INLINE
@@ -79,7 +85,7 @@ class TinyMatrix
         AB(i, j) = sum;
       }
     }
-    return std::move(AB);
+    return AB;
   }
 
   PUGS_INLINE
@@ -94,7 +100,7 @@ class TinyMatrix
       }
       Ax[i] = sum;
     }
-    return std::move(Ax);
+    return Ax;
   }
 
   PUGS_INLINE
@@ -143,7 +149,7 @@ class TinyMatrix
     for (size_t i = 0; i < N * N; ++i) {
       sum.m_values[i] = m_values[i] + A.m_values[i];
     }
-    return std::move(sum);
+    return sum;
   }
 
   PUGS_INLINE
@@ -164,7 +170,7 @@ class TinyMatrix
     for (size_t i = 0; i < N * N; ++i) {
       difference.m_values[i] = m_values[i] - A.m_values[i];
     }
-    return std::move(difference);
+    return difference;
   }
 
   PUGS_INLINE
@@ -306,7 +312,7 @@ tensorProduct(const TinyVector<N, T>& x, const TinyVector<N, T>& y)
       A(i, j) = x[i] * y[j];
     }
   }
-  return std::move(A);
+  return A;
 }
 
 template <size_t N, typename T>
@@ -404,7 +410,7 @@ getMinor(const TinyMatrix<N, T>& A, const size_t& I, const size_t& J)
       M(i - 1, j - 1) = A(i, j);
     }
   }
-  return std::move(M);
+  return M;
 }
 
 template <size_t N, typename T>
@@ -418,7 +424,7 @@ inverse(const TinyMatrix<1, T>& A)
   static_assert(std::is_floating_point<T>::value, "inverse is defined for floating point types only");
 
   TinyMatrix<1, T> A_1(1. / A(0, 0));
-  return std::move(A_1);
+  return A_1;
 }
 
 template <size_t N, typename T>
@@ -442,7 +448,7 @@ inverse(const TinyMatrix<2, T>& A)
   const T inv_determinent = 1. / determinent;
 
   TinyMatrix<2, T> A_cofactors_T(A(1, 1), -A(0, 1), -A(1, 0), A(0, 0));
-  return std::move(A_cofactors_T *= inv_determinent);
+  return A_cofactors_T *= inv_determinent;
 }
 
 template <typename T>
@@ -458,7 +464,7 @@ inverse(const TinyMatrix<3, T>& A)
                                  cofactor(A, 1, 1), cofactor(A, 2, 1), cofactor(A, 0, 2), cofactor(A, 1, 2),
                                  cofactor(A, 2, 2));
 
-  return std::move(A_cofactors_T *= 1. / determinent);
+  return A_cofactors_T *= 1. / determinent;
 }
 
 #endif   // TINYMATRIX_HPP