[Bug fortran/31016] Use __buildin_memcpy and __memcpy for array assignment

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=31016

--- Comment #11 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Correction: The rank-1 copying cases are now handled by the middle end,
the two-dimensional case isn't.