https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63638
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Looks good, but please include the testcase for the testsuite (you can use __builtin_memcpy or declare extern #ifdef __cplusplus "C" #endif void *memcpy (void *, const void *, __SIZE_TYPE__); ), the testcase should go to trunk too.