https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77405
--- Comment #25 from John Marino <gnugcc at marino dot st> --- I'm being told (one source) that that 16-byte alignment is not a x86-64 abi requirement. I don't know either way. Do you have an iron-clad reference about this requirement? (Yes I know __gnat_malloc is libc malloc)
