https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77405
--- Comment #23 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to John Marino from comment #22) > (gdb) p/x $rax > $1 = 0x800af0748 Your __gnat_malloc doesn't return memory aligned to 16 bytes. This violates x86-64 psABI.