[Bug tree-optimization/98868] [8/9/10/11 Regression] polyhedron rnflow.f90 regression since r8-2555-g344be1fd47d7d64e

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98868

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
First of call I can reproduce no runtime difference on a Zen2 machine.

We do get a lot better ranges after the change (that was the purpose).  For
example

-_490: [-INF, +INF]
-_491: [-INF, 2147483646]
+_490: [-INF, 512]
+_491: [-INF, 511]
...
-_63: [-INF, +INF]
-_64: [-INF, 2147483646]
+_63: [2, +INF]
+_64: [1, 2147483646]

which means we likely get more jump threading done which may result in
code layout changes.  Moving the binaries to a zen1 machine does not
reproduce the issue either.  I can't see the specified jump in the graph
either.