Darren Reed writes:

>Maybe they need adddi3.s then, which uses carry-bit, etc, to run
>faster if that adddi3.c doesn't compile down fast enough ?

If its doable in assembler, it should be done as a define_expand.
Two extra loads, two extra stores, and an add-with-carry.

If someone really wanted to get keen, we'd only build, on any given
arch, the libgcc backent support code that's acutall needed on that
arch...