[Bug tree-optimization/127070] [14/15/16/17 Regression] wrong code at -O3 on x86_64-linux-gnu (generated code hangs)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127070

--- Comment #2 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 65422
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65422&action=edit
Slightly reduced

Added debug printfs. note the commented out ones seems to break the loop too.

Note also ao, al and ap can't be marked as noipa because IPA modref needs to
know they don't clobber some references it seems.