[Bug target/69868] vec_perm built-in is not handled by swap optimization on powerpc64le

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69868

--- Comment #2 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Created attachment 37759
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37759&action=edit
Tentative patch (needs refactoring)

Attaching a tested patch that solves the problem for this case without
regressing the test suite.  This patch is a bit rough and will need some
refactoring.  I'll upload another version when I get some more time to work on
this.  Patch will be queued up for next stage 1.