https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109025
--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> --- This is a latent issue where we are mis-detecting a double reduction. Since we've loosened constraint on nested cycle detection we failed to beef up constraints we put on double reductions. Testing a minimal patch. Coverage of weird double reductions isn't too great though so thanks for this testcase.
