[Bug target/78594] Bug in November 11th, 2016 change to rs6000.md

[meissner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78594

--- Comment #1 from Michael Meissner <meissner at gcc dot gnu.org> ---
Created attachment 40191
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40191&action=edit
Proposed patch that fixes the problem.