Fix buffers for GCC 7 with -O3

src/core/mpi/RecvBuffer.h

@@ -38,7 +38,7 @@
 #include <boost/utility/enable_if.hpp>
 
 #include <algorithm>
-
+#include <cstring>
 
 namespace walberla {
 namespace mpi {
@@ -389,7 +389,6 @@ inline bool GenericRecvBuffer<T>::isEmpty() const
 */
 template< typename T >  // Element type
 template< typename V >  // Type of the built-in data value
-ATTRIBUTE_NO_SANITIZE_UNDEFINED
 typename boost::enable_if< boost::mpl::or_< boost::is_arithmetic<V>, boost::is_enum<V> >,
                            GenericRecvBuffer<T> & >::type
 GenericRecvBuffer<T>::get( V& value )
@@ -408,9 +407,8 @@ GenericRecvBuffer<T>::get( V& value )
    WALBERLA_ASSERT_LESS_EQUAL( cur_ + (sizeof(V) / sizeof(T)), end_ );
 
    // Extracting the data value
-   V* tmp = reinterpret_cast<V*>( cur_ );
-   value = *tmp;
-   cur_  = reinterpret_cast<T*>( ++tmp );
+   std::memcpy( &value, cur_, sizeof(V) );
+   cur_ += sizeof(V) / sizeof(T);
 
    // Invariants check
    WALBERLA_ASSERT_LESS_EQUAL( cur_, end_);

src/core/mpi/SendBuffer.h

@@ -42,7 +42,7 @@
 
 #include <algorithm>
 #include <typeinfo>
-
+#include <cstring>
 
 namespace walberla {
 namespace mpi {
@@ -443,7 +443,6 @@ inline bool GenericSendBuffer<T,G>::isEmpty() const
 template< typename T    // Element type
           , typename G >  // Growth policy
 template< typename V >  // Type of the built-in data value
-ATTRIBUTE_NO_SANITIZE_UNDEFINED
 typename boost::enable_if< boost::mpl::or_< boost::is_arithmetic<V>, boost::is_enum<V> >,
 GenericSendBuffer<T,G>& >::type
 GenericSendBuffer<T,G>::put( V value )
@@ -464,8 +463,7 @@ GenericSendBuffer<T,G>::put( V value )
    }
 
    // Adding the data value
-   V* const tmp( reinterpret_cast<V*>( cur_ ) );
-   *tmp  = value;
+   std::memcpy( cur_, &value, sizeof(V) );
    cur_ += count;
 
    // Invariants check