[Bug target/99041] combine creates invalid address which ICEs in decompose_normal_address

[bergner at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99041

--- Comment #10 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Peter Bergner from comment #9)
> Fixed on trunk.
> 
> I will check whether we need this on the GCC10 branch as well.  I believe we
> probably will.

Confirmed, we need this on GCC10 as well.  Segher approved the backport
offline.  I'll let the trunk commit bake a few days and then will push the
backport.