As I mentioned in my previous post, in Go 1.9, the new minimum processor requirement for ppc64 Big Endian will be POWER8.
I started cleaning up old code that was required to maintain compatibility with POWER5 to POWER7 in the SSA backend and in the atomics implementation. Commits c644a76 and 189053a remove some checks that were preventing ppc64 from using (and benefiting from) instruction sequences we added for ppc64le, which would break older processors support.
This is another step forward making ppc64 and ppc64le differ only in endianess, and not in functionality or performance. If you spot any other legacy code that needs removal, patches are welcome!