[Bug tree-optimization/59967] [12/13/14/15 Regression] Performance regression from 4.7.x to 4.8.x (loop not unrolled)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59967

--- Comment #26 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 60464
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=60464&action=edit
trimmed down testcase with just the important function