[Bug rtl-optimization/97784] Expressions evaluated as long chain instead of as tree or the like

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97784

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reassociation is done for signed types and places where it could introduce
overflows.

If you -fwrapv, you should get the optimization. Likewise for unsigned types.